JP7547892B2 - Display device components, display devices and electronic devices - Google Patents

Description

This disclosure relates to display device components, display devices, and electronic devices.

Conventionally, display devices have used glass or resin cover members to protect the display device. These cover members protect the display device from impacts and scratches, and are required to have strength, impact resistance, scratch resistance, etc. Glass cover members are characterized by high surface hardness, scratch resistance, and high transparency, while resin cover members are characterized by being lightweight and shatter-resistant. In general, the thicker the cover member, the better its ability to protect the display device from impacts, and the material and thickness of the cover member are appropriately selected based on the weight, cost, size of the display device, etc.

In recent years, flexible displays such as foldable displays, rollable displays, and bendable displays have been actively developed, and in particular, the development of foldable displays, i.e., display devices that can be bent, is progressing.

In bendable display devices, the cover member must also bend in accordance with the movement of the display device, and so a bendable cover member is used. In the case of resin cover members, polyimide or polyamide-imide films that have been made colorless and transparent by devising chemical structures have been developed (see, for example, Patent Document 1). In the case of glass cover members, studies are being conducted on cover members that can be bent by thinning the glass, such as ultra-thin glass (UTG) (see, for example, Patent Document 2). Among glass, chemically strengthened glass has particularly high bending resistance, and by incorporating an expanding stress in the glass surface, minute scratches on the glass surface are prevented from becoming larger when the glass is bent, making the glass less likely to break.

Glass has a higher elastic modulus than resin, so for the same thickness, it is more capable of protecting a display device than resin. Glass is also highly optically transparent, making it possible to manufacture display devices with better visibility. On the other hand, as glass becomes thinner, it becomes more fragile, and its impact resistance decreases dramatically. If the glass of the cover member breaks due to an external impact, not only will its ability to protect the display device decrease, but the resulting fragments and sharp edges may injure the user's fingertips, etc.

Therefore, it has been proposed to laminate a resin layer onto a glass substrate. For example, Patent Document 3 discloses a laminate of glass and a cured resin layer.

JP 2019-137864 A JP 2018-188335 A JP 2010-280092 A

In a display device that includes a laminate having a glass substrate and a resin layer, by arranging the resin layer closer to the viewer than the glass substrate, the resin layer can suppress glass cracking due to impact and improve impact resistance. However, if the resin layer is made thicker to improve impact resistance, bending resistance decreases. On the other hand, if the resin layer is made thin from the perspective of bending resistance, sufficient impact resistance cannot be obtained. Therefore, there is a demand for display device components that can achieve both bending resistance and impact resistance.

This disclosure has been made in consideration of the above-mentioned circumstances, and has as its main objective the provision of a display device component that has good bending resistance and impact resistance, as well as improved safety.

In order to solve the above problems, the inventors of the present disclosure have conducted intensive research and have found that in a display device member in which a resin layer and a functional layer are arranged in this order on one surface side of a thin glass substrate, good bending resistance and impact resistance can be achieved by controlling the film thickness distribution of the resin layer and the functional layer and setting the average value of the total thickness of the resin layer and the functional layer and the maximum value of the total thickness of the resin layer and the functional layer within a predetermined range. In addition, in a display device member in which a resin layer is arranged on one surface side of a thin glass substrate, the inventors have found that good bending resistance and impact resistance can be achieved by controlling the film thickness distribution of the resin layer and setting the average thickness of the resin layer and the maximum thickness of the resin layer within a predetermined range. The present disclosure is based on such findings.

One embodiment of the present disclosure provides a display device member having a glass substrate, a resin layer, and a functional layer in this order, in which the glass substrate has a thickness of 100 μm or less, the average total thickness of the resin layer and the functional layer is 19 μm or more and 60 μm or less, and the maximum total thickness of the resin layer and the functional layer is 60 μm or less.

In the display device member of this embodiment, the functional layer is preferably a hard coat layer.

In the display device component of this embodiment, it is preferable that the average thickness of the functional layer is 5 μm or more and less than 15 μm.

In the display device member of this embodiment, it is preferable that the ratio of the maximum value of the total thickness of the resin layer and the functional layer to the average value of the total thickness of the resin layer and the functional layer is 132% or less.

In the display device member of this embodiment, the resin layer and the functional layer have raised portions at their ends, and when the cross-sectional shape of the raised portions is approximated to a triangle, the height of the triangle is the difference between the maximum value of the total thickness of the resin layer and the functional layer and the average value of the total thickness of the resin layer and the functional layer, and the length of the base of the triangle is the distance from the end of the resin layer and the functional layer to a position where the total thickness of the raised portions of the resin layer and the functional layer becomes the average value of the total thickness of the resin layer and the functional layer, it is preferable that the area of the triangle is ^0.08 mm2 or less.

In the above case, it is preferable that the ratio of the average thickness of the functional layer to the average total thickness of the resin layer and the functional layer is 10% or more and 65% or less.

Another embodiment of the present disclosure provides a display device member having a glass substrate, a resin layer, a first functional layer, and a functional film in this order, the functional film having, from the first functional layer side, an adhesive layer, a substrate layer, and a second functional layer, the thickness of the glass substrate being 100 μm or less, the average total thickness of the resin layer and the first functional layer being 10 μm or more and 60 μm or less, and the maximum total thickness of the resin layer and the first functional layer being 60 μm or less.

In the display device member of this embodiment, it is preferable that the first functional layer and the second functional layer are hard coat layers.

In the display device component of this embodiment, it is preferable that the average thickness of the functional film is 20 μm or more and 150 μm or less.

In the display device member of this embodiment, it is preferable that the average thickness of the first functional layer is 5 μm or more and less than 15 μm, and the average thickness of the second functional layer is 5 μm or more and less than 15 μm.

In the display device member of this embodiment, it is preferable that the ratio of the maximum value of the total thickness of the resin layer and the first functional layer to the average value of the total thickness of the resin layer and the first functional layer is 132% or less.

In the display device member of this embodiment, when the resin layer and the first functional layer have raised portions at their ends and the cross-sectional shape of the raised portions is approximated to a triangle, and the height of the triangle is the difference between the maximum value of the total thickness of the resin layer and the first functional layer and the average value of the total thickness of the resin layer and the first functional layer, and the length of the base of the triangle is the distance from the end of the resin layer and the first functional layer to a position where the total thickness of the raised portions of the resin layer and the first functional layer becomes the average value of the total thickness of the resin layer and the first functional layer, it is preferable that the area of the triangle is 0.08 ^mm2 or less.

In the above case, it is preferable that the ratio of the average thickness of the first functional layer to the average total thickness of the resin layer and the first functional layer is 10% or more and 65% or less.

Another embodiment of the present disclosure provides a display device member having a glass substrate, a resin layer, and a functional film in this order, and the functional film has, from the resin layer side, an adhesive layer, a substrate layer, and a functional layer in this order, in which the glass substrate has a thickness of 100 μm or less, the resin layer has an average thickness of 10 μm or more and 60 μm or less, and the resin layer has a maximum thickness of 60 μm or less.

In the display device member of this embodiment, the functional layer is preferably a hard coat layer.

In the display device component of this embodiment, it is preferable that the average thickness of the functional film is 20 μm or more and 150 μm or less.

In the display device component of this embodiment, it is preferable that the average thickness of the functional layer is 5 μm or more and less than 15 μm.

In the display device member of this embodiment, it is preferable that the ratio of the maximum thickness of the resin layer to the average thickness of the resin layer is 130% or less.

In the display device member of this embodiment, the resin layer has a raised portion at an end portion, and when the cross-sectional shape of the raised portion is approximated to a triangle, and the height of the triangle is the difference between the maximum thickness of the resin layer and the average thickness of the resin layer, and the length of the base of the triangle is the distance from the end of the resin layer to the position where the total thickness of the raised portions of the resin layer becomes the average thickness of the resin layer, it is preferable that the area of the triangle is 0.08 ^mm2 or less.

Another embodiment of the present disclosure provides a display device including a display panel and the above-described display device component disposed on the viewer side of the display panel.

Another embodiment of the present disclosure provides an electronic device including the display device described above.

The present disclosure has the effect of providing display device components that have good bending resistance and impact resistance, and also have improved safety.

1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic perspective view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. FIG. 1 is a schematic diagram for explaining a dynamic bending test. FIG. 1 is a schematic diagram for explaining a static bending test. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device member according to the present disclosure. 1 is a schematic cross-sectional view illustrating a display device according to the present disclosure. 4 is a graph showing the distribution of the total thickness of a resin layer and a hard coat layer in members for a display device of Examples and Comparative Examples.

Below, an embodiment of the present disclosure will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms, and should not be interpreted as being limited to the description of the embodiment exemplified below. In addition, in order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual form, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, elements similar to those described above with respect to the previous figures are given the same reference numerals, and detailed explanations may be omitted as appropriate.

In this specification, when describing a mode in which another component is placed on a certain component, the term "above" or "below" is used, unless otherwise specified, to include both cases in which another component is placed directly above or below a certain component so as to be in contact with the component, and cases in which another component is placed above or below a certain component with another component in between. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the term "on the surface side" or "on the surface" is used, unless otherwise specified, to include both cases in which another component is placed directly above or below a certain component so as to be in contact with the component, and cases in which another component is placed above or below a certain component with another component in between.

The display device components and display devices of this disclosure are described in detail below.

A. Display Device Member The display device member of the present disclosure has three embodiments. Each embodiment will be described below.

I. First embodiment A first embodiment of the display device member of the present disclosure is a display device member having a glass substrate, a resin layer, and a functional layer in this order, wherein the thickness of the glass substrate is 100 μm or less, the average value of the total thickness of the resin layer and the functional layer is 19 μm or more and 60 μm or less, and the maximum value of the total thickness of the resin layer and the functional layer is 60 μm or less.

1 is a schematic cross-sectional view showing an example of a display device member in this embodiment. As shown in FIG. 1, the display device member 1 has a glass substrate 2, a resin layer 3, and a functional layer 4 in this order. The glass substrate 2 has a predetermined thickness. In addition, the average value of the total thickness of the resin layer 3 and the functional layer 4 is within a predetermined range, and the maximum value T1 _max of the total thickness of the resin layer 3 and the functional layer 4 is equal to or less than a predetermined value.

Here, when the resin layer 3 and the functional layer 4 are formed on one surface of the glass substrate 2 by a coating method, the thicknesses of the ends of the resin layer 3 and the functional layer 4 tend to increase due to surface tension, resulting in the formation of raised portions 11 at the ends of the resin layer 3 and the functional layer 4. In the example shown in Fig. 1, the maximum value of the total thickness of such raised portions 11 of the resin layer 3 and the functional layer 4 is the maximum value _T1max of the total thickness of the resin layer 3 and the functional layer 4.

In the display device member of this embodiment, the glass substrate is thin, with a thickness equal to or less than a predetermined value, and so there are concerns that it may be prone to cracking and have low impact resistance. However, since a resin layer and a functional layer are arranged in this order on one side of the glass substrate, and the average total thickness of the resin layer and the functional layer is equal to or greater than a predetermined value, when an impact is applied to the display device member, the resin layer absorbs the impact and can suppress cracking of the glass substrate, thereby improving impact resistance.

Here, as described above, when a resin layer and a functional layer are formed on one side of a glass substrate by a coating method, the thickness of the ends of the resin layer and the functional layer increases due to surface tension, and as shown in FIG. 1, for example, raised portions 11 tend to occur at the ends of the resin layer 3 and the functional layer 4. If raised portions exist at the ends of the resin layer and the functional layer, cracks, whitening, wrinkles, etc. are likely to occur in the resin layer and the functional layer starting from the raised portions when the display device member is bent.

In contrast, in the display device member of this embodiment, the average value of the total thickness of the resin layer and the functional layer is within a predetermined range, and the maximum value of the total thickness of the resin layer and the functional layer is equal to or less than a predetermined value, thereby suppressing the occurrence of cracks, whitening, wrinkles, etc. in the resin layer and the functional layer when the display device member is bent, and improving bending resistance.

Therefore, in this embodiment, the display device component can achieve both good bending resistance and impact resistance.

In addition, in the display device member of this embodiment, a resin layer and a functional layer are arranged in this order on one side of the glass substrate, so that it is possible to increase the hardness of the surface on the functional layer side of the display device member, thereby improving scratch resistance.

Furthermore, in the display device member of this embodiment, the resin layer and the functional layer are arranged in this order on one side of the glass substrate, so that even if the glass substrate is broken, the glass can be prevented from scattering. This reduces the risk of injury to the human body, making it possible to provide a display device member that is highly safe.

The display device member in this embodiment can therefore be folded and used in a wide variety of display devices, for example as a foldable display member.

The following describes each component of the display device in this embodiment.

1. Thickness of the resin layer and the functional layer In this embodiment, the average value of the total thickness of the resin layer and the functional layer can be 19 μm or more and 60 μm or less, preferably 25 μm or more and 55 μm or less, more preferably 30 μm or more and 50 μm or less. By the average value of the total thickness of the resin layer and the functional layer being within the above range, it is possible to suppress the cracking of the glass substrate due to impact, improve the impact resistance, and suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer and the functional layer when the display device member is bent, thereby improving the bending resistance. On the other hand, if the average value of the total thickness of the resin layer and the functional layer is too small, the impact resistance may be reduced. In addition, if the average value of the total thickness of the resin layer and the functional layer is too large, the bending resistance may be reduced.

In addition, in this embodiment, the maximum value of the total thickness of the resin layer and the functional layer is 60 μm or less, and preferably 55 μm or less. By having the maximum value of the total thickness of the resin layer and the functional layer within the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer and the functional layer when the display device member is bent, and to improve bending resistance. In particular, when the functional layer is a hard coat layer, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the hard coat layer when the display device member is bent. On the other hand, if the maximum value of the total thickness of the resin layer and the functional layer is too large, bending resistance may be reduced.

Here, as described above, when the resin layer and the functional layer are formed on one surface of the glass substrate by a coating method, the thickness of the ends of the resin layer and the functional layer increases due to surface tension, and as shown in FIG. 1, for example, raised portions 11 tend to occur at the ends of the resin layer 3 and the functional layer 4. In this case, the maximum value of the total thickness of the resin layer and the functional layer is the maximum value of the total thickness of the raised portions of the resin layer and the functional layer. In such a case, for example, when the planar shape of the resin layer and the functional layer is rectangular or square, it is sufficient that the maximum value of the total thickness of the resin layer and the functional layer at the end of at least one of the four sides of the resin layer and the functional layer satisfies the above range.

In particular, it is preferable that the maximum value of the total thickness of the resin layer and the functional layer is within the above range at the ends of two opposing sides of the resin layer and the functional layer. For example, as shown in Figures 2(a) and (b), when the display device member 1 is bent, cracks, whitening, wrinkles, etc. are likely to occur in the resin layer and the functional layer at the bent portion 13 of the display device member 1. Therefore, if the maximum value of the total thickness of the resin layer and the functional layer is within the above range at the ends of two sides that are approximately parallel to the bending direction 12 of the display device member 1 among the four sides of the resin layer and the functional layer, the occurrence of cracks, whitening, wrinkles, etc. in the bent portions of the resin layer and the functional layer when the display device member is bent can be suppressed, and bending resistance can be improved.

In addition, when the planar shape of the resin layer and the functional layer is rectangular, it is preferable that the maximum value of the total thickness of the resin layer and the functional layer at the ends of two opposing long sides of the four sides of the resin layer and the functional layer is within the above range. For example, as shown in Figures 2(a) and (b), when bending the display device member 1, the bending direction 12 of the display device member 1 is often made approximately parallel to the long side direction of the resin layer and the functional layer because it is easy to bend. Therefore, if the maximum value of the total thickness of the resin layer and the functional layer at the ends of two opposing long sides of the four sides of the resin layer and the functional layer is within the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the bending parts of the resin layer and the functional layer when the display device member is bent, and to improve bending resistance.

Furthermore, for the reasons mentioned above, it is preferable that the maximum value of the total thickness of the resin layer and the functional layer is within the above range at the ends of two of the four sides of the resin layer and the functional layer that are approximately parallel to the bending direction of the display device member.

In particular, it is preferable that the maximum total thickness of the resin layer and the functional layer is within the above range at all four ends of the resin layer and the functional layer. This can further improve bending resistance.

Methods for controlling the maximum value of the total thickness of the resin layer and the functional layer to be within a predetermined range include, for example, a method of incorporating a leveling agent into the resin layer and the functional layer, a method of forming a resin layer and a functional layer on one side of a glass substrate to obtain a laminate and then cutting the laminate, and a method of transferring the resin layer and the functional layer to one side of a glass substrate.

In addition, in this embodiment, the ratio of the maximum value of the total thickness of the resin layer and the functional layer to the average value of the total thickness of the resin layer and the functional layer is, for example, preferably 132% or less, and may be 125% or less. By having the above ratio within the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer and the functional layer when the display device member is bent, and to improve bending resistance. In particular, when the functional layer is a hard coat layer, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the hard coat layer when the display device member is bent. On the other hand, if the above ratio is too large, there is a risk of reduced bending resistance.

Here, the total thickness of the resin layer and the functional layer can be measured by microscopic cross-sectional observation or a stylus method. In microscopic cross-sectional observation, for example, a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM) is used to observe the cross section of the display device member in the thickness direction, and the total thickness of the resin layer and the functional layer can be obtained from the obtained image. In addition, in the stylus method, for example, a stylus film thickness gauge is used to measure the film thickness by tracing the surface of the display device member with a stylus, and the total thickness of the resin layer and the functional layer can be obtained from the obtained film thickness profile data.

The average value of the total thickness of the resin layer and the functional layer is the arithmetic mean value of the total thickness at any 10 points in the area other than the raised portion when the resin layer 3 and the functional layer 4 have the raised portion 11, for example, as shown in FIG. 1. On the other hand, when the resin layer and the functional layer do not have the raised portion, the average value of the total thickness of the resin layer and the functional layer can be the arithmetic mean value of the total thickness at any 10 points.

In addition, the maximum value of the total thickness of the resin layer and the functional layer is the maximum value of the total thickness of the raised portion of the resin layer and the functional layer when the resin layer 3 and the functional layer 4 have a raised portion 11, for example as shown in FIG. 1. On the other hand, when the resin layer and the functional layer do not have a raised portion, the maximum value of the total thickness of the resin layer and the functional layer can be the maximum value of the total thickness of any 10 points.

In this embodiment, the average thickness of the functional layer is, for example, preferably 5 μm or more and less than 15 μm, and more preferably 7 μm or more and 13 μm or less. By having the average thickness of the functional layer in the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the functional layer when the display device member is bent, and to improve the bending resistance. In particular, when the functional layer is a hard coat layer, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the hard coat layer when the display device member is bent. On the other hand, if the average thickness of the functional layer is too large, the bending resistance may be reduced. Also, if the average thickness of the functional layer is too small, the characteristics of the functional layer may be reduced. For example, when the functional layer is a hard coat layer, if the average thickness of the hard coat layer is too small, sufficient scratch resistance may not be obtained.

In addition, the ratio of the average thickness of the functional layer to the average total thickness of the resin layer and the functional layer is, for example, preferably 10% or more and 65% or less, more preferably 15% or more and 60% or less, and even more preferably 20% or more and 55% or less. By having the above ratio within the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the functional layer when the display device member is bent, and to improve bending resistance. In particular, when the functional layer is a hard coat layer, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the hard coat layer when the display device member is bent. On the other hand, if the above ratio is too large, bending resistance may decrease. Also, if the above ratio is too small, the thickness of the functional layer may become thin, and the characteristics of the functional layer may deteriorate. For example, when the functional layer is a hard coat layer, if the above ratio is too small, the thickness of the hard coat layer may become thin, and sufficient scratch resistance may not be obtained.

Here, the method for measuring the thickness of the functional layer can be the same as the method for measuring the combined thickness of the resin layer and the functional layer described above.

The average thickness of the functional layer is, for example, as shown in FIG. 1, the arithmetic mean value of the thicknesses at any 10 points in the area other than the raised portion when the functional layer 4 has a raised portion 11. On the other hand, when the functional layer does not have a raised portion, the average thickness of the functional layer can be the arithmetic mean value of the thicknesses at any 10 points.

The average thickness of the resin layer is not particularly limited as long as it satisfies the average value of the total thickness of the resin layer and the functional layer, and the average thickness of the functional layer, and is, for example, preferably 10 μm or more and 55 μm or less, more preferably 15 μm or more and 45 μm or less, and even more preferably 20 μm or more and 35 μm or less. By making the average thickness of the resin layer relatively thin so as to be within the above range, flexibility can be increased, and when the display device member is bent, the occurrence of cracks, whitening, wrinkles, etc. in the resin layer can be suppressed, and bending resistance can be maintained.

Here, the method for measuring the thickness of the resin layer can be the same as the method for measuring the combined thickness of the resin layer and the functional layer described above.

The average thickness of the resin layer is the arithmetic mean value of the thicknesses at any 10 points in the area other than the raised portion when the resin layer 3 has a raised portion 11, as shown in FIG. 1, for example. On the other hand, when the resin layer does not have a raised portion, the average thickness of the resin layer can be the arithmetic mean value of the thicknesses at any 10 points.

In this embodiment, the resin layer and the functional layer have a raised portion at the end, and the cross-sectional shape of the raised portion is approximated to a triangle, and the height of the triangle is the difference between the maximum value of the total thickness of the resin layer and the functional layer and the average value of the total thickness of the resin layer and the functional layer, and the length of the base of the triangle is the distance from the end of the resin layer and the functional layer to the position where the total thickness of the raised portion of the resin layer and the functional layer becomes the average value of the total thickness of the resin layer and the functional layer. The area of the triangle is, for example, preferably 0.08 mm ² or less, more preferably 0.07 mm ² or less, and even more preferably 0.06 mm ² or less. By having the area of the triangle in the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer and the functional layer when the display device member is bent, and to improve the bending resistance. In particular, when the functional layer is a hard coat layer, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the hard coat layer when the display device member is bent. On the other hand, if the area of the triangle is too large, the bending resistance may be reduced.

Here, the case where the cross-sectional shape of the raised portion of the resin layer and the functional layer is approximated to a triangle will be described with reference to FIG. 3. As shown in FIG. 3, the cross-sectional shape of the raised portion 11 of the resin layer 3 and the functional layer 4 is approximated to a triangle 14 shown by a dashed line. The height H1 of the triangle 14 is the difference between the maximum value T1 _max of the total thickness of the resin layer 3 and the functional layer 4 and the average value T1 _ave of the total thickness of the resin layer 3 and the functional layer 4. The length D1 of the base of the triangle 14 is the distance from the end of the resin layer 3 and the functional layer 4 to the position P1 where the total thickness of the raised portion 11 of the resin layer 3 and the functional layer 4 becomes the average value T1 _ave of the total thickness of the resin layer 3 and the functional layer 4.

The position P1 where the total thickness of the raised portion 11 of the resin layer 3 and the functional layer 4 becomes the average value T1 _ave of the total thickness of the resin layer 3 and the functional layer 4 is the position in the raised portion 11 where the total thickness of the raised portion 11 of the resin layer 3 and the functional layer 4 changes from the maximum value T1 _max of the total thickness of the resin layer 3 and the functional layer 4 as it moves away from the end of the resin layer 3 and the functional layer 4, and becomes the average value T1 _ave of the total thickness of the resin layer 3 and the functional layer 4.

In addition, with regard to the position where the total thickness of the raised portions of the resin layer and the functional layer from the end of the resin layer and the functional layer becomes the average value of the total thickness of the resin layer and the functional layer, if there are multiple peaks of the total thickness of the resin layer 3 and the functional layer 4 in the raised portions 11 of the resin layer 3 and the functional layer 4 as shown in Figure 4, and the total thickness of the raised portions 11 of the resin layer 3 and the functional layer 4 changes from the maximum value T1 _max of the total thickness of the resin layer 3 and the functional layer 4 as it moves away from the end of the resin layer 3 and the functional layer 4, and there are multiple positions P1 and P2 where the total thickness becomes the average value T1 _ave of the total thickness of the resin layer 3 and the functional layer 4, then of these positions P1 and P2, the position P1 furthest from the end of the resin layer 3 and the functional layer 4 is used.

2. Resin layer The resin layer in the present disclosure is a layer disposed on one side of the glass substrate. The resin layer can also function as an impact absorbing layer having impact absorbing properties, or as a shatterproof layer that suppresses glass from scattering when the glass substrate is broken. The resin layer has transparency, and when the member for a display device in the present disclosure is disposed on the viewer side of the display panel of the display device, the resin layer is disposed on the viewer side of the glass substrate.

(1) Characteristics of the resin layer The resin layer preferably has impact absorption properties. Specifically, the composite elastic modulus of the resin layer is preferably 4.7 GPa or more, more preferably 5.7 GPa or more. By having the composite elastic modulus of the resin layer in the above range, it is possible to suppress the cracking of the glass substrate due to impact, and to improve impact resistance and scratch resistance.

In addition, according to the composite elastic modulus measurement method described below, the composite elastic modulus of the glass substrate is approximately 40 GPa, so the composite elastic modulus of the resin layer is preferably, for example, 40 GPa or less, and more preferably 20 GPa or less.

Here, the composite elastic modulus of the resin layer is calculated using the contact projection area A _p obtained when measuring the indentation hardness (H _IT ) of the resin layer. "Indentation hardness" is a value obtained from a load-displacement curve from loading to unloading of the indenter obtained by hardness measurement using a nanoindentation method. The composite elastic modulus of the resin layer is an elastic modulus including the elastic deformation of the resin layer and the elastic deformation of the indenter.

The indentation hardness (H _IT ) is measured using a BRUKER "TI950 TriboIndenter". Specifically, a block is prepared by embedding a display device member cut into 1 mm x 10 mm with an embedding resin, and a uniform slice having a thickness of 50 nm to 100 nm without holes is cut out from this block by a general slice preparation method. An "Ultramicrotome EM UC7" (Leica Microsystems) or the like can be used to prepare the slice. The remaining block from which the uniform slice without holes is cut out is used as the measurement sample. Next, in the cross section obtained by cutting out the slice in such a measurement sample, a Berkovich indenter (triangular pyramid, BRUKER TI-0039) is pressed vertically into the center of the cross section of the resin layer for 10 seconds to a maximum pressing load of 25 μN under the following measurement conditions. Here, in order to avoid the influence of the glass substrate and the side edges of the resin layer, the Berkovich indenter is pushed into a portion of the resin layer that is 500 nm away from the interface between the glass substrate and the resin layer toward the center of the resin layer, and 500 nm away from each of the ends of the resin layer toward the center of the resin layer. Also, the indenter is pushed into a portion of the resin layer that is 500 nm away from the interface between the functional layer and the resin layer toward the center of the resin layer. After that, the residual stress is relaxed by holding it constant, and then the load is removed over 10 seconds to measure the maximum load after relaxation. Using the maximum load P _max (μN) and the contact projected area A _p (nm ² ), the indentation hardness (H _IT ) is calculated by P _max /A _p . The contact projected area is the contact projected area obtained by correcting the indenter tip curvature by the Oliver-Pharr method using a standard sample of fused quartz (5-0098 manufactured by BRUKER). The indentation hardness (H _IT ) is the arithmetic average value of the values obtained by measuring at 10 points. If the measured values include any that deviate from the arithmetic average value by ±20% or more, the measured values are excluded and remeasured. Whether or not any of the measured values deviate from the arithmetic average value by ±20% or more is determined by whether the value (%) calculated by (A-B)/Bx100, where A is the measured value and B is the arithmetic average value, is ±20% or more. The indentation hardness (H _IT ) can be adjusted by the type of resin contained in the resin layer, which will be described later.

(Measurement conditions)
・Loading speed: 2.5μN/sec ・Holding time: 5 seconds ・Unloading speed: 2.5μN/sec ・Measurement temperature: 25℃

The composite elastic modulus E _r of the resin layer is calculated using the contact projected area A _p calculated when measuring the indentation hardness according to the following formula (1). The composite elastic modulus is calculated by measuring the indentation hardness at 10 points, calculating the composite elastic modulus each time, and calculating the arithmetic average value of the composite elastic moduli at the 10 points.

(In the above formula (1), A _p is the contact projected area, E _r is the composite elastic modulus of the resin layer, and S is the contact stiffness.)

(2) Materials for Resin Layer (a) Resin The resin contained in the resin layer is not particularly limited as long as it satisfies the above-mentioned composite elastic modulus and has transparency, and examples thereof include polyimide resins, acrylic resins, epoxy resins, urethane resins, polyesters, triacetyl cellulose (TAC), polycarbonate resins, etc. These resins may be used alone or in combination of two or more.

In this specification, polyimide resin refers to a polymer having imide bonds in the main chain. Examples of polyimide resins include polyimide, polyamideimide, polyesterimide, and polyetherimide.

The following explanation uses polyimide as an example.

(Polyimide)
Polyimide is obtained by reacting a tetracarboxylic acid component with a diamine component. It is preferable to obtain a polyamic acid by polymerization of the tetracarboxylic acid component and the diamine component, and then imidize the polyamic acid. The imidization may be performed by chemical imidization, thermal imidization, or a combination of chemical imidization and thermal imidization.

The polyimide is not particularly limited as long as it satisfies the composite elastic modulus and has transparency, but for example, it is preferable that the polyimide contains 10 mol % to 100 mol % of the structural unit represented by the following general formula (1) and (100-x) mol % (where x is the mol % of the structural unit represented by the above general formula (1)) of the structural unit represented by the following general formula (2), and has a weight average molecular weight of 100,000 or more. This is because the polyimide has a tetracarboxylic acid residue of a specific structure containing a parabiphenylene group with a twisted dihedral angle via an ester bond in the main chain, and a diamine residue having an aromatic ring or an aliphatic ring, and has a specific weight average molecular weight, which makes it easy to achieve a good balance between the composite elastic modulus and bending resistance.

(In general formulas (1) and (2), R ¹ to R ⁴ each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and at least one of R ¹ and R ² , and at least one of R ³ and R ⁴ , represents an alkyl group having 1 to 6 carbon atoms. A represents a tetravalent group which is a tetracarboxylic acid residue having an aromatic ring or an aliphatic ring, and B represents a divalent group which is a diamine residue having an aromatic ring or an aliphatic ring.)

Here, the tetracarboxylic acid residue refers to a residue obtained by removing four carboxyl groups from a tetracarboxylic acid, and has the same structure as the residue obtained by removing the acid dianhydride structure from a tetracarboxylic dianhydride. Also, the diamine residue refers to a residue obtained by removing two amino groups from a diamine.

In the general formula (1), at least one of R ¹ and R ² , and at least one of R ³ and R ⁴ , represents an alkyl group having 1 to 6 carbon atoms. The alkyl group having 1 to 6 carbon atoms may be a linear or branched alkyl group, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, and an n-hexyl group. From the viewpoint of solvent solubility, an alkyl group having 1 to 4 carbon atoms is preferable, an alkyl group having 1 to 2 carbon atoms is more preferable, and a methyl group is more preferable. Among them, from the viewpoint of solvent solubility, it is preferable that R ¹ and R ² , and R ³ and R ⁴ represent a methyl group.

In general formula (1), B represents a divalent group that is a diamine residue having an aromatic ring or an aliphatic ring. The diamine residue having an aromatic ring or an aliphatic ring can be a residue obtained by removing two amino groups from a diamine having an aromatic ring or a diamine having an aliphatic ring.

Specific examples of diamines having an aromatic ring and diamines having an aliphatic ring include those described in, for example, JP-A-2019-132930 and JP-A-2019-1989. These can be used alone or in combination of two or more.

In the above general formula (2), A represents a tetravalent group that is a tetracarboxylic acid residue having an aromatic ring or an aliphatic ring, and B represents a divalent group that is a diamine residue having an aromatic ring or an aliphatic ring. B in the above general formula (2) may be the same as B in the above general formula (1), so the explanation here is omitted. B in the above general formula (1) and B in the above general formula (2) may be the same or different.

The tetracarboxylic acid residue in A of the above general formula (2) can be a residue obtained by removing an acid dianhydride structure from a tetracarboxylic acid dianhydride having an aromatic ring, or a residue obtained by removing an acid dianhydride structure from a tetracarboxylic acid dianhydride having an aliphatic ring.

Specific examples of tetracarboxylic dianhydrides having an aromatic ring and tetracarboxylic dianhydrides having an aliphatic ring include those described in, for example, JP-A-2019-132930 and JP-A-2019-1989. These can be used alone or in combination of two or more.

The polyimide preferably contains 10 mol % or more and 100 mol % or less of the structural unit represented by the above general formula (1). From the viewpoint of solubility in a solvent, the polyimide more preferably contains 15 mol % or more of the structural unit represented by the above general formula (1), even more preferably contains 25 mol % or more, and particularly preferably contains 50 mol % or more.

On the other hand, in order to improve surface hardness and transparency, a copolymer component may be included, and the polyimide may contain 95 mol % or less, 90 mol % or less, or 80 mol % or less of the structural unit represented by the above general formula (1).

The polyimide preferably contains (100-x) mol % (where x is the mol % of the structural unit represented by the general formula (1)) of the structural unit represented by the general formula (2). From the viewpoint of solubility in a solvent, the polyimide more preferably contains 85 mol % or less of the structural unit represented by the general formula (2), even more preferably contains 75 mol % or less, and particularly preferably contains 50 mol % or less.

When the polyimide contains 100 mol% of the structural unit represented by the above general formula (1), the structural unit represented by the above general formula (2) is 0 mol%, i.e., not contained. The structural unit represented by the above general formula (2) may be 0 mol%, but may be contained as a copolymerization component in order to improve surface hardness and transparency. The polyimide may contain 5 mol% or more, 10 mol% or more, or 20 mol% or more of the structural unit represented by the above general formula (2).

From the viewpoint of improving transparency and surface hardness, it is preferable that at least one of the tetravalent group of the tetracarboxylic acid residue of A and the divalent group of the diamine residue of B contains an aromatic ring and at least one selected from the group consisting of (i) a fluorine atom, (ii) an aliphatic ring, and (iii) a structure in which aromatic rings are linked together by an alkylene group that may be substituted with a sulfonyl group or fluorine. When the polyimide contains at least one selected from a tetracarboxylic acid residue having an aromatic ring and a diamine residue having an aromatic ring, the molecular skeleton becomes rigid, the orientation is increased, and the surface hardness is improved, but the rigid aromatic ring skeleton tends to have an absorption wavelength that extends to a long wavelength, and the transmittance in the visible light region tends to decrease. On the other hand, when the polyimide contains (i) a fluorine atom, the transparency is improved because the electronic state in the polyimide skeleton can be made difficult to charge transfer. In addition, when the polyimide contains (ii) an aliphatic ring, the conjugation of the π electrons in the polyimide skeleton can be broken, thereby inhibiting the movement of charges in the skeleton, and thus improving transparency. In addition, when the polyimide contains (iii) a structure in which aromatic rings are linked together by a sulfonyl group or an alkylene group which may be substituted with fluorine, the conjugation of the π electrons in the polyimide skeleton can be broken, thereby inhibiting the movement of charges in the skeleton, and thus improving transparency.

In particular, from the viewpoint of improving transparency and surface hardness, it is preferable that at least one of the tetravalent group which is the tetracarboxylic acid residue of A and the divalent group which is the diamine residue of B contains an aromatic ring and a fluorine atom, and it is preferable that the divalent group which is the diamine residue of B contains an aromatic ring and a fluorine atom.

In terms of transparency, bending resistance and surface hardness, the polyimide is preferably selected from the group consisting of a trans-cyclohexanediamine residue, a trans-1,4-bismethylenecyclohexanediamine residue, a 4,4'-diaminodiphenylsulfone residue, a 3,4'-diaminodiphenylsulfone residue, a 2,2-bis(4-aminophenyl)propane residue, a 3,3'-bis(trifluoromethyl)-4,4'-[ It is preferably at least one divalent group selected from the group consisting of (1,1,1,3,3,3-hexafluoropropane-2,2-diyl)bis(4,1-phenyleneoxy)]dianiline residue, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane residue, 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane residue, and divalent groups represented by the following general formula (3): In particular, from the viewpoint of achieving both transparency and surface hardness, it is preferable that the divalent group is at least one selected from the group consisting of 4,4'-diaminodiphenylsulfone residue, 3,4'-diaminodiphenylsulfone residue, 2,2-bis(4-aminophenyl)propane residue, and divalent groups represented by the following general formula (3), and more preferably the divalent group represented by the following general formula (3). As the divalent group represented by the following general formula (3), R ⁵ and R ⁶ are more preferably perfluoroalkyl groups, and among them, perfluoroalkyl groups having 1 to 3 carbon atoms are preferred, and trifluoromethyl groups or perfluoroethyl groups are more preferred. Furthermore, as the alkyl groups in R ⁵ and R ⁶ in the following general formula (3), alkyl groups having 1 to 3 carbon atoms are preferred, and more preferably methyl groups or ethyl groups.

(In formula (3), ^R5 and ^R6 each independently represent a hydrogen atom, an alkyl group, or a perfluoroalkyl group.)

In particular, from the standpoints of transparency, bending resistance and surface hardness, the polyimide is preferably one in which the tetracarboxylic acid residue having an aromatic ring or an aliphatic ring in A in the above general formula (2) is a cyclohexanetetracarboxylic acid dianhydride residue, a cyclopentanetetracarboxylic acid dianhydride residue, a dicyclohexane-3,4,3',4'-tetracarboxylic acid dianhydride residue, a cyclobutanetetracarboxylic acid dianhydride residue, a pyromellitic acid dianhydride residue, a 3,3',4,4'-biphenyltetracarboxylic acid dianhydride residue, a 2,2',3,3' It is preferable that the tetravalent group is at least one selected from the group consisting of -biphenyltetracarboxylic dianhydride residue, 2,3,3',4'-biphenyltetracarboxylic dianhydride residue, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride residue, 3,4'-(hexafluoroisopropylidene)diphthalic anhydride residue, 3,3'-(hexafluoroisopropylidene)diphthalic anhydride residue, 4,4'-oxydiphthalic anhydride residue, and 3,4'-oxydiphthalic anhydride residue.

In the above general formula (2), A preferably contains 50 mol % or more of these suitable residues in total, more preferably 70 mol % or more, and even more preferably 90 mol % or more.

In terms of improving surface hardness, it is preferable that A in the above general formula (2) contains a tetracarboxylic acid residue group (Group A) suitable for improving rigidity, such as at least one selected from the group consisting of pyromellitic dianhydride residues, 3,3',4,4'-biphenyltetracarboxylic dianhydride residues, and 2,2',3,3'-biphenyltetracarboxylic dianhydride residues. In addition, from the viewpoint of improving transparency, A in the above general formula (2) preferably includes at least one tetracarboxylic acid residue group (Group B) suitable for improving transparency, such as cyclohexane tetracarboxylic dianhydride residue, cyclopentane tetracarboxylic dianhydride residue, dicyclohexane-3,4,3',4'-tetracarboxylic dianhydride residue, cyclobutane tetracarboxylic dianhydride residue, 2,3,3',4'-biphenyl tetracarboxylic dianhydride residue, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride residue, 3,4'-(hexafluoroisopropylidene)diphthalic anhydride residue, 3,3'-(hexafluoroisopropylidene)diphthalic anhydride residue, 4,4'-oxydiphthalic anhydride residue, and 3,4'-oxydiphthalic anhydride residue. Group A and Group B may be used in combination.

When Group A and Group B are mixed, the content ratio of the tetracarboxylic acid residue group suitable for improving the above-mentioned rigidity (Group A) to the tetracarboxylic acid residue group suitable for improving transparency (Group B) is preferably 0.05 mol or more and 9 mol or less of the tetracarboxylic acid residue group suitable for improving the above-mentioned rigidity (Group A) per 1 mol of the tetracarboxylic acid residue group suitable for improving transparency (Group B), more preferably 0.1 mol or more and 5 mol or less, and even more preferably 0.3 mol or more and 4 mol or less.

Among these, from the viewpoint of improving surface hardness and transparency, it is preferable to use at least one of 4,4'-(hexafluoroisopropylidene)diphthalic anhydride residues and 3,4'-(hexafluoroisopropylidene)diphthalic anhydride residues, both of which contain fluorine atoms, as the group B.

The content ratio of each repeating unit in the polyimide and the content ratio (mol %) of each tetracarboxylic acid residue and each diamine residue can be determined from the molecular weight of the feed when the polyimide is produced. The content ratio (mol %) of each tetracarboxylic acid residue and each diamine residue in the polyimide can be determined by using high performance liquid chromatography, gas chromatography mass spectrometry, NMR, elemental analysis, XPS/ESCA and TOF-SIMS for the decomposition products of the polyimide obtained in the same manner as above.

In terms of good flex resistance, the polyimide preferably has a weight average molecular weight of 100,000 or more as calculated using polystyrene standards by gel permeation chromatography. In terms of flex resistance, the weight average molecular weight may be 120,000 or more, 140,000 or more, or 160,000 or more. On the other hand, in terms of preventing bubble defects from occurring, the weight average molecular weight is preferably 270,000 or less. Furthermore, in terms of solubility, the weight average molecular weight may be 250,000 or less, 230,000 or less, or 210,000 or less.

The weight-average molecular weight of polyimide can be measured by gel permeation chromatography (GPC). Specifically, polyimide is dissolved in N-methylpyrrolidone (NMP) at a concentration of 0.1% by mass, and the developing solvent is a 30 mmol% LiBr-NMP solution with a water content of 500 ppm or less. Measurements are performed using a Tosoh GPC device (HLC-8120, column used: SHODEX GPC LF-804) with a sample injection volume of 50 μL, a solvent flow rate of 0.4 mL/min, and 37°C. The weight-average molecular weight is determined based on a polystyrene standard sample of the same concentration as the sample.

(b) Leveling Agent The resin layer preferably contains a leveling agent. By containing the leveling agent in the resin layer, the maximum value of the total thickness of the resin layer and the functional layer can be controlled to be within a predetermined range, and raised portions can be prevented from being generated at the ends of the resin layer and the functional layer.

The leveling agent contained in the resin layer is not particularly limited, and examples thereof include silicone-based leveling agents, fluorine-based leveling agents, acrylic-based leveling agents, vinyl-based leveling agents, etc. These leveling agents may be used alone or in combination of two or more. Among them, silicone-based leveling agents and fluorine-based leveling agents are preferred because of their high ability to reduce surface tension.

The content of the leveling agent in the resin layer is not particularly limited, but is preferably 0.01% by mass to 3% by mass, more preferably 0.05% by mass to 2% by mass, and even more preferably 0.1% by mass to 1% by mass. If the content of the leveling agent is too small, the effect of the leveling agent may not be fully obtained. If the content of the leveling agent is too high, the strength of the resin layer may decrease. If the leveling agent is a silicone-based leveling agent or a fluorine-based leveling agent, if the content of the leveling agent is too high, there is a risk of repelling or peeling when forming a functional layer on the resin layer.

(c) UV absorber The resin layer may contain a UV absorber. The UV absorber can suppress the deterioration of the resin layer due to UV rays. In particular, when the resin layer contains polyimide, the color change over time of the polyimide-containing resin layer can be suppressed. In addition, in a display device including a display device member, the UV absorber can suppress the deterioration of a member arranged on the display panel side of the display device member, such as a polarizer, due to UV rays.

Examples of UV absorbents contained in the resin layer include triazine-based UV absorbents, benzophenone-based UV absorbents such as hydroxybenzophenone-based UV absorbents, and benzotriazole-based UV absorbents.

Specific examples of triazine-based UV absorbers, benzophenone-based UV absorbers such as hydroxybenzophenone-based UV absorbers, and benzotriazole-based UV absorbers include those described in JP 2019-132930 A.

Among the UV absorbents, triazine-based UV absorbents, hydroxybenzophenone-based UV absorbents, and benzotriazole-based UV absorbents are preferably used.

The ultraviolet absorber is preferably a polymer or oligomer, because this can suppress bleeding out of the ultraviolet absorber when the display device member is repeatedly bent. Examples of such ultraviolet absorbers include polymers or oligomers having a triazine skeleton, a benzophenone skeleton, or a benzotriazole skeleton, and specifically, it is preferable that the ultraviolet absorber is a thermal copolymerization of a (meth)acrylate having a benzotriazole skeleton or a benzophenone skeleton and methyl methacrylate (MMA) in any ratio.

The content of the ultraviolet absorber in the resin layer is not particularly limited, but is preferably, for example, 1% by mass to 6% by mass, and more preferably 2% by mass to 5% by mass. If the content of the ultraviolet absorber is too low, the effect of the ultraviolet absorber may not be fully obtained. If the content of the ultraviolet absorber is too high, the resin layer may be significantly discolored or the strength of the resin layer may be reduced.

(d) Other Additives The resin layer may further contain additives as necessary, such as inorganic particles, silica filler for facilitating winding, surfactants for improving film-forming properties and defoaming properties, and adhesion improvers.

(3) Configuration of Resin Layer In this embodiment, the resin layer may have a raised portion at the end. As described above, when a resin layer is formed on one side of a glass substrate by a coating method, the thickness of the end of the functional layer increases due to surface tension, and a raised portion 11 tends to occur at the end of the resin layer 3, as shown in FIG. 1, for example. In this embodiment, by suppressing the raised portion at the end of the resin layer, the maximum value of the total thickness of the raised portion of the resin layer and the functional layer can be set to a predetermined value or less, and bending resistance can be improved.

The resin layer may be a single layer or may have multiple layers. Furthermore, when the resin layer has multiple layers, the materials of the multiple layers may be the same or different from each other. Furthermore, when the resin layer has multiple layers, the average thicknesses of the multiple layers may be the same or different from each other.

(4) Method for forming a resin layer As a method for forming a resin layer, for example, a method of applying a resin composition onto a glass substrate can be mentioned. The application method is not particularly limited as long as it can be applied to a desired thickness, and examples thereof include general application methods such as gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, screen printing, and die coating. In addition, a transfer method for transferring a resin layer onto a glass substrate can also be used as a method for forming a resin layer. Among them, the die coating method and the transfer method are preferred because they are less likely to form raised portions at the ends.

The following describes an example in which the resin layer contains polyimide.

(Method of forming a polyimide-containing resin layer)
Examples of methods for forming a resin layer containing polyimide include a method of applying a polyimide varnish containing polyimide and an organic solvent onto a glass substrate and drying it, and a method of applying a polyimide precursor composition containing a polyimide precursor (polyamic acid) and an organic solvent onto a glass substrate, and then imidizing the polyimide precursor by heat treatment or chemical treatment. The former method can ease the heating conditions of the film formation process. On the other hand, the latter method can increase the options for the chemical structure of polyimide, since there is no restriction on the solubility of polyimide.

Among these, the following manufacturing method is preferred because it is less likely to cause air bubble defects and makes it easier to obtain a resin layer with good thickness uniformity.

The method for forming a resin layer containing polyimide preferably includes a preparation step of preparing a polyimide varnish containing polyimide and an organic solvent, the content of the polyimide being 6% by mass or more and 15% by mass or less in the polyimide varnish, and having a viscosity at 25°C of 1,000 cps or more and 50,000 cps or less, a coating step of coating the polyimide varnish onto a glass substrate, a first drying step of drying the coating at a temperature of 140°C or less, and a second drying step of heating the coating at a temperature of 200°C or more after drying.

When polyimide dissolves well in organic solvents, the heating conditions in the film-forming process can be alleviated, so it is preferable to form the resin layer using a polyimide varnish in which polyimide is dissolved in an organic solvent. When polyimide has a specific amount or more of structural units containing tetracarboxylic acid residues of a specific structure containing a parabiphenylene group with a twisted dihedral angle via an ester bond in the main chain, it is easily soluble in an organic solvent. When polyimide has a solvent solubility such that 6% by mass or more of the polyimide dissolves in an organic solvent at 25°C, the above-mentioned method for forming a resin layer can be suitably used.

The above-mentioned method for forming a resin layer makes it possible to increase the polyimide content in the varnish to a sufficient concentration, and to adjust the varnish to a desired viscosity range, so that a resin layer with good thickness uniformity and with fewer air bubble defects can be obtained.

The organic solvent is not particularly limited as long as it can dissolve polyimide, and for example, aprotic polar solvents or water-soluble alcohol solvents can be used. Among them, it is preferable to use organic solvents containing nitrogen atoms such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, hexamethylphosphoramide, 1,3-dimethyl-2-imidazolidinone, and γ-butyrolactone. The organic solvents can be used alone or as a mixed solvent of two or more kinds.

For methods of forming the resin layer containing the above polyimide, see, for example, the methods described in JP-A-2019-1989 and JP-A-2019-182974.

3. Functional Layer The functional layer in the present disclosure is a layer disposed on the side of the resin layer opposite to the glass substrate. An example of the functional layer is a hard coat layer.

The hard coat layer is a layer for increasing the surface hardness. The presence of the hard coat layer can improve scratch resistance.

(1) Characteristics of the Hard Coat Layer Here, the term "hard coat layer" refers to a layer for increasing the surface hardness, and specifically refers to a layer that exhibits a hardness of "H" or more when a pencil hardness test specified in JIS K 5600-5-4 (1999) is carried out on a member for a display device.

The pencil hardness of the surface of the hard coat layer side of the display device member is, for example, preferably H or more, more preferably 2H or more, and even more preferably 3H or more.

Here, the pencil hardness is measured by the pencil hardness test specified in JIS K5600-5-4 (1999). Specifically, the pencil hardness test specified in JIS K5600-5-4 (1999) is performed on the surface of the hard coat layer side of the display device member using a test pencil specified in JIS-S-6006, and the highest pencil hardness that does not cause scratches is evaluated. The pencil hardness is measured on a display device member having a glass substrate, a resin layer, and a hard coat layer in this order. The measurement conditions can be an angle of 45°, a load of 750 g, a speed of 0.5 mm/sec or more and 1 mm/sec or less, and a temperature of 23±2°C. As a pencil hardness tester, for example, a pencil scratch coating hardness tester manufactured by Toyo Seiki Co., Ltd. can be used.

The hard coat layer is a layer that is harder than the resin layer. Specifically, the composite elastic modulus of the hard coat layer is preferably higher than the composite elastic modulus of the resin layer. The composite elastic modulus of the hard coat layer is preferably, for example, 4.8 GPa or more, and more preferably 5.8 GPa or more.

In addition, according to the above-mentioned method for measuring the composite elastic modulus, since the composite elastic modulus of the glass substrate is approximately 40 GPa, the composite elastic modulus of the hard coat layer is preferably, for example, 40 GPa or less, and more preferably 20 GPa or less.

The method for measuring the composite elastic modulus of the hard coat layer can be the same as the method for measuring the composite elastic modulus of the resin layer.

(2) Configuration of hard coat layer In this embodiment, the hard coat layer may have a raised portion at the end. As described above, when a resin layer is formed on one side of a glass substrate by a coating method, the thickness of the end of the hard coat layer increases due to surface tension, and as shown in FIG. 1, for example, a raised portion 11 tends to occur at the end of the functional layer 4 (hard coat layer). In this embodiment, by suppressing the raised portion at the end of the hard coat layer, the maximum value of the total thickness of the raised portion of the resin layer and the functional layer (hard coat layer) can be set to a predetermined value or less, and bending resistance can be improved.

The hard coat layer may be a single layer or may have multiple layers. When the hard coat layer has multiple layers, it is preferable that the hard coat layer has a layer for satisfying the pencil hardness and a layer for satisfying the dynamic bending test (a layer for satisfying the scratch resistance) in order to improve the surface hardness and to achieve a good balance between the bending resistance and the elastic modulus.

(3) Materials for the hard coat layer (a) Polymerizable compound Examples of materials for the hard coat layer include resin compositions containing polymerizable compounds. Specifically, the hard coat layer preferably contains a cured product of a resin composition containing a polymerizable compound. The cured product of a resin composition containing a polymerizable compound can be obtained by polymerizing the polymerizable compound by a known method using a polymerization initiator as necessary.

A polymerizable compound has at least one polymerizable functional group in the molecule. As the polymerizable compound, for example, at least one of a radical polymerizable compound and a cationic polymerizable compound can be used.

A radically polymerizable compound is a compound having a radically polymerizable group. The radically polymerizable group of a radically polymerizable compound is not particularly limited as long as it is a functional group capable of causing a radical polymerization reaction, but examples thereof include groups containing a carbon-carbon unsaturated double bond, and specific examples thereof include a vinyl group and a (meth)acryloyl group. Note that when a radically polymerizable compound has two or more radically polymerizable groups, these radically polymerizable groups may be the same or different.

The number of radically polymerizable groups that the radically polymerizable compound has in one molecule is preferably 2 or more, and more preferably 3 or more, in order to improve the hardness of the hard coat layer.

As the radical polymerizable compound, from the viewpoint of high reactivity, a compound having a (meth)acryloyl group is preferable. For example, polyfunctional (meth)acrylate monomers and oligomers having several (meth)acryloyl groups in the molecule and a molecular weight of several hundred to several thousand, such as urethane (meth)acrylate, polyester (meth)acrylate, epoxy (meth)acrylate, melamine (meth)acrylate, polyfluoroalkyl (meth)acrylate, silicone (meth)acrylate, etc., can be preferably used. Also, polyfunctional (meth)acrylate polymers having two or more (meth)acryloyl groups in the side chain of the acrylate polymer can be preferably used. Among them, polyfunctional (meth)acrylate monomers having two or more (meth)acryloyl groups in one molecule can be preferably used. By including a cured product of a polyfunctional (meth)acrylate monomer in the hard coat layer, the hardness of the hard coat layer can be improved and the adhesion can be further improved. Also preferably used are polyfunctional (meth)acrylate oligomers or polymers having two or more (meth)acryloyl groups in one molecule. By including a cured product of a polyfunctional (meth)acrylate oligomer or polymer in the hard coat layer, the hardness and flex resistance of the hard coat layer can be improved, and the adhesion can be further improved.

In this specification, (meth)acryloyl refers to both acryloyl and methacryloyl, and (meth)acrylate refers to both acrylate and methacrylate.

Specific examples of polyfunctional (meth)acrylate monomers include those described in JP 2019-132930 A. Among them, from the viewpoints of high reactivity, improved hardness of the hard coat layer, and adhesion, those having 3 to 6 (meth)acryloyl groups in one molecule are preferred. For example, pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), pentaerythritol tetraacrylate (PETTA), dipentaerythritol pentaacrylate (DPPA), trimethylolpropane tri(meth)acrylate, tripentaerythritol octa(meth)acrylate, tetrapentaerythritol deca(meth)acrylate, etc. can be preferably used, and in particular, at least one selected from pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexaacrylate, and those modified with PO, EO, or caprolactone are preferred.

The resin composition may contain a monofunctional (meth)acrylate monomer as a radical polymerizable compound for adjusting hardness and viscosity, improving adhesion, etc. Specific examples of monofunctional (meth)acrylate monomers include those described in JP 2019-132930 A.

A cationic polymerizable compound is a compound having a cationic polymerizable group. The cationic polymerizable group of a cationic polymerizable compound is not particularly limited as long as it is a functional group capable of causing a cationic polymerization reaction, and examples of the cationic polymerizable group include an epoxy group, an oxetanyl group, and a vinyl ether group. When a cationic polymerizable compound has two or more cationic polymerizable groups, these cationic polymerizable groups may be the same or different.

The number of cationically polymerizable groups that the cationically polymerizable compound has in one molecule is preferably 2 or more, and more preferably 3 or more, in order to improve the hardness of the hard coat layer.

Among the cationic polymerizable compounds, compounds having at least one of epoxy and oxetanyl groups as cationic polymerizable groups are preferred, and compounds having at least two or more of epoxy and oxetanyl groups in one molecule are more preferred. Cyclic ether groups such as epoxy and oxetanyl groups are preferred because they cause little shrinkage during polymerization. Among cyclic ether groups, compounds having epoxy groups have the advantages of being readily available in a variety of structures, not adversely affecting the durability of the obtained hard coat layer, and being easy to control compatibility with radically polymerizable compounds. Among cyclic ether groups, oxetanyl groups have the advantages of having a higher degree of polymerization and lower toxicity than epoxy groups, and of accelerating the network formation rate obtained from the cationic polymerizable compound in the coating film when the obtained hard coat layer is combined with a compound having an epoxy group, and forming an independent network without leaving unreacted monomers in the film even in areas where the radically polymerizable compound is mixed.

Examples of cationic polymerizable compounds having an epoxy group include alicyclic epoxy resins obtained by epoxidizing polyglycidyl ethers of polyhydric alcohols having an alicyclic ring or compounds containing a cyclohexene ring or cyclopentene ring with a suitable oxidizing agent such as hydrogen peroxide or peracid; aliphatic epoxy resins such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts, polyglycidyl esters of aliphatic long-chain polybasic acids, and homopolymers and copolymers of glycidyl (meth)acrylate; glycidyl ethers produced by reacting bisphenols such as bisphenol A, bisphenol F, and hydrogenated bisphenol A, or derivatives thereof such as alkylene oxide adducts or caprolactone adducts, with epichlorohydrin, and novolac epoxy resins, etc., which are derived from bisphenols.

Specific examples of alicyclic epoxy resins, glycidyl ether type epoxy resins, and cationic polymerizable compounds having an oxetanyl group include those described in JP 2018-104682 A.

The cured product of the resin composition containing the polymerizable compound contained in the hard coat layer can be analyzed using a Fourier transform infrared spectrophotometer (FTIR) or a pyrolysis gas chromatograph (GC-MS), and the decomposition products of the polymer can be analyzed using a combination of high performance liquid chromatography, a gas chromatograph mass spectrometer, NMR, elemental analysis, XPS/ESCA, and TOF-SIMS.

(b) Polymerization initiator The above-mentioned resin composition may contain a polymerization initiator as necessary. As the polymerization initiator, radical polymerization initiator, cationic polymerization initiator, radical and cationic polymerization initiator, etc. can be appropriately selected and used. These polymerization initiators are decomposed by at least one of light irradiation and heating to generate radicals or cations, and promote radical polymerization and cationic polymerization. In addition, there are cases where the polymerization initiator is completely decomposed and does not remain in the hard coat layer.

Specific examples of radical polymerization initiators and cationic polymerization initiators include those described in JP 2018-104682 A.

(c) Particles The hard coat layer preferably contains inorganic or organic particles, and more preferably inorganic fine particles. When the hard coat layer contains particles, the hardness can be improved.

Examples of inorganic particles include metal oxide particles such as silica (SiO ₂ ), aluminum oxide, zirconia, titania, zinc oxide, germanium oxide, indium oxide, tin oxide, indium tin oxide (ITO), antimony oxide, and cerium oxide, metal fluoride particles such as magnesium fluoride and sodium fluoride, metal particles, metal sulfide particles, and metal nitride particles. Among these, metal oxide particles are preferred, and at least one selected from silica particles and aluminum oxide particles is more preferred, with silica particles being even more preferred, because excellent hardness can be obtained.

The inorganic particles are preferably reactive inorganic particles having photoreactive reactive functional groups on at least a part of the particle surface that undergo a crosslinking reaction between the inorganic particles themselves or between the inorganic particles themselves and at least one type of polymerizable compound to form a covalent bond. The hardness of the hard coat layer can be further improved by crosslinking between the reactive inorganic particles themselves or between the reactive inorganic particles themselves and at least one type of radically polymerizable compound and cationic polymerizable compound.

Reactive inorganic particles have at least a portion of their surface covered with an organic component, and have reactive functional groups on the surface introduced by the organic component. For example, a polymerizable unsaturated group is preferably used as the reactive functional group, and a photocurable unsaturated group is more preferably used. For example, reactive functional groups include ethylenically unsaturated bonds such as (meth)acryloyl groups, vinyl groups, and allyl groups, and epoxy groups.

The reactive silica particles are not particularly limited, and conventionally known ones can be used, such as the reactive silica particles described in JP 2008-165040 A. Commercially available reactive silica particles include, for example, MIBK-SD, MIBK-SDMS, MIBK-SDL, and MIBK-SDZL manufactured by Nissan Chemical Industries, Ltd., and V8802 and V8803 manufactured by JGC Catalysts and Chemicals Co., Ltd.

The silica particles may be spherical silica particles, but are preferably irregular silica particles. Spherical silica particles and irregular silica particles may be mixed. In this specification, irregular silica particles refer to silica particles having random potato-like irregularities on the surface. Since irregular silica particles have a larger surface area than spherical silica particles, the inclusion of such irregular silica particles increases the contact area with the resin components, etc., and the hardness of the hard coat layer can be improved.

Whether or not the particles are amorphous silica particles can be confirmed by observing the cross section of the hard coat layer using an electron microscope.

From the viewpoint of improving hardness, the average particle size of the inorganic particles is preferably 5 nm or more, and more preferably 10 nm or more. If the average particle size of the inorganic particles is too small, it may be difficult to manufacture the particles, and the particles may be prone to agglomeration. From the viewpoint of transparency, the average particle size of the inorganic particles is preferably 200 nm or less, more preferably 100 nm or less, and even more preferably 50 nm or less. If the average particle size of the inorganic particles is too large, there is a risk that large irregularities will be formed in the hard coat layer or that the haze will be high.

Here, the average particle size of the inorganic particles can be measured by observing the cross section of the hard coat layer with an electron microscope, and the average particle size is the average of the particle sizes of 10 arbitrarily selected particles. The average particle size of the irregular silica particles is the average of the maximum (long axis) and minimum (short axis) distances between two points on the periphery of the irregular silica particles that appear when the hard coat layer is observed in cross section with a microscope.

The hardness of the hard coat layer can be controlled by adjusting the size and content of the inorganic particles. For example, the content of the silica particles is preferably 25 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the polymerizable compound.

(d) Leveling Agent The hard coat layer preferably contains a leveling agent. By containing the leveling agent in the hard coat layer, the maximum value of the total thickness of the resin layer and the functional layer can be controlled to be within a predetermined range, and raised portions can be prevented from being generated at the ends of the resin layer and the functional layer.

The leveling agent contained in the hard coat layer is not particularly limited, and examples thereof include silicone-based leveling agents, fluorine-based leveling agents, acrylic-based leveling agents, vinyl-based leveling agents, and the like. These leveling agents may be used alone or in combination of two or more. Among these, silicone-based leveling agents and fluorine-based leveling agents are preferred because of their high ability to reduce surface tension.

The content of the leveling agent in the hard coat layer is not particularly limited, but is preferably 0.01% by mass or more and 3% by mass or less, more preferably 0.05% by mass or more and 2% by mass or less, and even more preferably 0.1% by mass or more and 1% by mass or less. If the content of the leveling agent is too small, the effect of the leveling agent may not be fully obtained. Also, if the content of the leveling agent is too large, the hardness of the hard coat layer may decrease.

(e) UV absorber The hard coat layer may contain a UV absorber. It is possible to suppress the deterioration of the resin layer due to UV rays. In particular, when the resin layer contains polyimide, it is possible to suppress the color change over time of the resin layer containing polyimide. In addition, in a display device including a display device member, it is possible to suppress the deterioration of a member arranged on the display panel side of the display device member, such as a polarizer, due to UV rays.

The ultraviolet absorber contained in the hard coat layer preferably has a peak absorption wavelength in absorbance measurement of 300 nm or more and 390 nm or less, more preferably 320 nm or more and 370 nm or less, and even more preferably 330 nm or more and 370 nm or less. This is because such an ultraviolet absorber can efficiently absorb ultraviolet rays in the UVA region, and at the same time, by shifting the peak wavelength from the absorption wavelength of 250 nm of the initiator for curing the hard coat layer, a hard coat layer having ultraviolet absorbing ability can be formed without causing inhibition of curing of the hard coat layer.

It is preferable that the UV absorber has a peak absorption wavelength of 380 nm or less, since this can prevent coloring caused by the UV absorber.

The absorbance of the UV absorber can be measured, for example, using a UV-visible-near infrared spectrophotometer (e.g., V-7100, manufactured by JASCO Corporation).

The ultraviolet absorbent may be the same as the ultraviolet absorbent used in the resin layer.

Among these, from the viewpoint of suppressing deterioration of the resin layer due to ultraviolet rays, one or more ultraviolet absorbers selected from the group consisting of hydroxybenzophenone-based ultraviolet absorbers and benzotriazole-based ultraviolet absorbers are preferred, and one or more ultraviolet absorbers selected from the group consisting of hydroxybenzophenone-based ultraviolet absorbers are more preferred.

Specific examples of hydroxybenzophenone-based UV absorbers include those described in JP 2019-132930 A.

Among the hydroxybenzophenone-based UV absorbers, 2-hydroxybenzophenone-based UV absorbers are preferred, and one or more selected from the group consisting of benzophenone-based UV absorbers having the following general formula (A) are more preferred. This can suppress deterioration of the resin layer caused by UV rays and improve durability.

(In general formula (A), ^X1 and ^X2 each independently represent a hydroxyl group, -OR ^a , or a hydrocarbon group having 1 to 15 carbon atoms, and R ^a represents a hydrocarbon group having 1 to 15 carbon atoms.)

In the general formula (A), examples of the hydrocarbon group having 1 to 15 carbon atoms in X ¹ , X ² and R ^a include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a dodecyl group, an allyl group, and a benzyl group. The aliphatic hydrocarbon group having 3 or more carbon atoms may each be linear or branched. The hydrocarbon group preferably has 1 to 12 carbon atoms, and more preferably has 1 to 8 carbon atoms. In terms of facilitating improvement in transparency, the hydrocarbon group is preferably an aliphatic hydrocarbon group, and among these, a methyl group and an allyl group are preferable.

From the viewpoint of facilitating improvement in durability, it is preferred that X ¹ and X ² each independently represent a hydroxyl group or -OR ^a .

As the one or more types selected from the group consisting of benzophenone-based ultraviolet absorbers having the general formula (A), it is preferable to select one or more types selected from the group consisting of 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, and 2,2'-dihydroxy-4,4'-diallyloxybenzophenone, and it is more preferable to select one or more types selected from the group consisting of 2,2',4,4'-tetrahydroxybenzophenone and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone.

Specific examples of benzotriazole-based UV absorbers include those described in JP 2019-132930 A.

Among them, 2-(2-hydroxyphenyl)benzotriazoles are preferred as benzotriazole-based UV absorbers, and one or more selected from the group consisting of benzotriazole-based UV absorbers having the following general formula (B) are more preferred. This can suppress deterioration of the resin layer caused by UV rays and improve durability.

(In general formula (B), Y ¹ , Y ² , and Y ³ each independently represent a hydrogen atom, a hydroxyl group, -OR ^b , or a hydrocarbon group having 1 to 15 carbon atoms, R ^b represents a hydrocarbon group having 1 to 15 carbon atoms, and at least one of Y ¹ , Y ² , and Y ³ represents a hydroxyl group, -OR ^b , or a hydrocarbon group having 1 to 15 carbon atoms. ^{Y 4} represents a hydrogen atom or a halogen atom.)

In the general formula (B), examples of the hydrocarbon group having 1 to 15 carbon atoms in Y ¹ , Y ² , and Y ³ and R ^b include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a dodecyl group. The aliphatic hydrocarbon group having 3 or more carbon atoms may each be linear or branched. The hydrocarbon group preferably has 1 to 12 carbon atoms, and more preferably has 1 to 8 carbon atoms. In terms of easiness in improving transparency, the hydrocarbon group is preferably an aliphatic hydrocarbon group, and is preferably a linear or branched alkyl group, and among these, a methyl group, a t-butyl group, a t-pentyl group, a n-octyl group, or a t-octyl group is preferable.

In formula (B), examples of the halogen atom in ^Y4 include a chlorine atom, a fluorine atom, and a bromine atom, and among these, a chlorine atom is preferable.

In general formula (B), it is preferable that Y ¹ and Y ³ are hydrogen atoms and Y ² is a hydroxyl group or -OR ^b , and more preferably one or more selected from the group consisting of 2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole and 2-(2,4-dihydroxyphenyl)-2H-benzotriazole. This can suppress deterioration of the resin layer due to ultraviolet rays and improve durability.

The content of the ultraviolet absorber in the hard coat layer is preferably, for example, 10% by mass or less, and more preferably 7% by mass or less, from the viewpoint of suppressing haze caused by mixing the ultraviolet absorber. Furthermore, from the viewpoint of suppressing deterioration of the resin layer due to ultraviolet rays and improving durability, the content of the ultraviolet absorber in the hard coat layer is preferably 1% by mass or more and 6% by mass or less, and more preferably 2% by mass or more and 5% by mass or less.

(f) Antifouling Agent The hard coat layer may contain an antifouling agent, which can impart antifouling properties to the member for a display device.

The antifouling agent is not particularly limited, and examples thereof include silicone-based antifouling agents, fluorine-based antifouling agents, and silicone-based and fluorine-based antifouling agents. The antifouling agent may also be an acrylic antifouling agent. One type of antifouling agent may be used alone, or two or more types may be used in combination.

Hard coat layers containing silicone-based or fluorine-based antifouling agents are less susceptible to fingerprints (less noticeable) and have good wiping properties. In addition, when silicone-based or fluorine-based antifouling agents are included, the surface tension of the hard coat layer curable resin composition can be reduced during application, resulting in good leveling properties and a good appearance for the resulting hard coat layer.

In addition, the hard coat layer containing the silicone-based antifouling agent has good slipperiness and good scratch resistance. In a display device including a display device component having a hard coat layer containing such a silicone-based antifouling agent, the slipperiness when touched with a finger, pen, etc. is improved, resulting in a good tactile sensation.

The antifouling agent preferably has a reactive functional group in order to increase the durability of the antifouling performance. If the antifouling agent does not have a reactive functional group, regardless of whether the display device member is in the form of a roll or a sheet, when the display device member is stacked, the antifouling agent will be transferred to the surface opposite the hard coat layer side of the display device member, and when another layer is attached or applied to the surface opposite the hard coat layer side of the display device member, the other layer may peel off, and further, the other layer may be easily peeled off when repeatedly bent. In contrast, when the antifouling agent has a reactive functional group, the antifouling performance is more durable.

The number of reactive functional groups in the antifouling agent may be 1 or more, and is preferably 2 or more. By using an antifouling agent having 2 or more reactive functional groups, it is possible to impart excellent scratch resistance to the hard coat layer.

The antifouling agent preferably has a weight average molecular weight of 5,000 or less. The weight average molecular weight of the antifouling agent can be measured by gel permeation chromatography (GPC).

The antifouling agent may be uniformly dispersed in the hard coat layer, but it is preferable that it is unevenly distributed on the surface side of the hard coat layer in order to obtain sufficient antifouling properties with a small amount of addition and to prevent a decrease in the strength of the hard coat layer.

Methods for unevenly distributing the antifouling agent on the surface side of the hard coat layer include, for example, a method in which, when forming the hard coat layer, a coating film of a curable resin composition for the hard coat layer is dried and before curing, the coating film is heated to reduce the viscosity of the resin components contained in the coating film and increase the fluidity, thereby unevenly distributing the antifouling agent on the surface side of the hard coat layer; a method in which an antifouling agent with low surface tension is used, the antifouling agent is floated on the surface of the coating film without applying heat when the coating film is dried, and the coating film is then cured, thereby unevenly distributing the antifouling agent on the surface side of the hard coat layer.

The content of the antifouling agent is preferably, for example, 0.01 parts by mass or more and 3.0 parts by mass or less per 100 parts by mass of the resin component. If the content of the antifouling agent is too low, sufficient antifouling properties may not be imparted to the hard coat layer, and if the content of the antifouling agent is too high, the hardness of the hard coat layer may decrease.

(g) Other Additives The hard coat layer can further contain additives as necessary.Additives are appropriately selected according to the function to be given to the hard coat layer, and are not particularly limited, but for example, inorganic or organic particles for adjusting refractive index, infrared absorbing agent, antiglare agent, antifouling agent, antistatic agent, coloring agent such as blue dye or purple dye, surfactant, easy lubricant, various sensitizers, flame retardant, adhesion promoter, polymerization inhibitor, antioxidant, light stabilizer, surface modifier, etc. can be mentioned.

(4) Method for Forming Hard Coat Layer Examples of a method for forming a hard coat layer include a method of applying a curable resin composition for a hard coat layer containing the above-mentioned polymerizable compound and the like onto the above-mentioned resin layer, followed by curing.

The curable resin composition for the hard coat layer contains a polymerizable compound, and may further contain a polymerization initiator, particles, an ultraviolet absorber, a solvent, additives, etc., as necessary.

The method of applying the hard coat layer curable resin composition onto the resin layer is not particularly limited as long as it is a method that allows application to the desired thickness, and examples of common application methods include gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, screen printing, and die coating. A transfer method can also be used to form a coating film of the hard coat layer resin composition. Among these, the die coating method and transfer method are preferred because they are less likely to form raised portions at the edges.

The coating film of the curable resin composition for the hard coat layer is dried as necessary to remove the solvent. Examples of drying methods include vacuum drying, heat drying, and a combination of these drying methods. For example, the coating film can be dried by heating at a temperature of 30°C or higher and 120°C or lower for 10 seconds or higher and 180 seconds or lower.

The method for curing the coating of the curable resin composition for the hard coat layer is appropriately selected depending on the polymerizable group of the polymerizable compound, and for example, at least one of light irradiation and heating can be used.

For light irradiation, ultraviolet light, visible light, electron beams, ionizing radiation, etc. are mainly used. In the case of ultraviolet curing, for example, ultraviolet light emitted from light rays of an ultra-high pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, a metal halide lamp, etc. can be used. The irradiation amount of the energy ray source can be, for example, about 50 mJ/ ^cm2 or more and 5000 mJ/ ^cm2 or less as an integrated exposure amount at an ultraviolet wavelength of 365 nm.

When heating is performed, the treatment can be performed at a temperature of, for example, 40°C or higher and 120°C or lower. The reaction can also be performed by leaving the mixture at room temperature (25°C) for 24 hours or more.

4. Glass Substrate The glass substrate in this embodiment has a thickness of 100 μm or less, and is a member that supports the resin layer and the functional layer.

The glass constituting the glass substrate is not particularly limited, but chemically strengthened glass is preferable. Chemically strengthened glass is preferable because it has excellent mechanical strength and can be made thinner accordingly. Chemically strengthened glass is typically glass whose mechanical properties have been strengthened by a chemical method, such as by partially exchanging ion species near the surface of the glass, such as by replacing sodium with potassium, and has a compressive stress layer on the surface.

Examples of glasses that can be used to make chemically strengthened glass substrates include aluminosilicate glass, soda-lime glass, borosilicate glass, lead glass, alkali barium glass, and aluminoborosilicate glass.

Commercially available chemically strengthened glass substrates include, for example, Corning's Gorilla Glass, AGC's Dragontrail, and Schott's chemically strengthened glass.

The thickness of the glass substrate is 100 μm or less, preferably 15 μm or more and 100 μm or less, more preferably 20 μm or more and 90 μm or less, and even more preferably 25 μm or more and 80 μm or less. By making the thickness of the glass substrate thin in the above range, it is possible to obtain good flexibility and sufficient hardness. It is also possible to suppress curling of the display device member. Furthermore, it is preferable in terms of reducing the weight of the display device member.

Here, the thickness of the glass substrate can be the average value of the thicknesses of any 10 locations obtained by measuring a cross section in the thickness direction of the display device member observed with a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM). Unless otherwise specified, the same can be said for the thicknesses of other layers in the display device member.

5. Other Configurations In addition to the above-mentioned layers, the display device member in this embodiment may have other layers as necessary. Examples of the other layers include a primer layer and a fingerprint prevention layer.

(1) Primer Layer The display device member in this embodiment may have a primer layer 5 between a glass substrate 2 and a resin layer 3, as shown in Fig. 5, for example. The primer layer can improve the adhesion between the glass substrate and the resin layer.

The material for the primer layer is not particularly limited as long as it is a material that can increase the adhesion between the glass substrate and the resin layer, and examples of the material include resins. Examples of resins include (meth)acrylic resins, urethane resins, (meth)acrylic urethane copolymers, vinyl chloride-vinyl acetate copolymer resins, polyesters, butyral resins, chlorinated polypropylene, chlorinated polyethylene, epoxy resins, silicone resins, and the like. These resins may be used alone or in combination of two or more.

The thickness of the primer layer may be any thickness that can increase the adhesion between the glass substrate and the resin layer or the second resin layer, and may be, for example, 0.1 μm or more and 10 μm or less, and preferably 0.2 μm or more and 5 μm or less.

For example, a method for forming a primer layer includes a method of applying a primer layer composition onto a glass substrate. Examples of application methods include general application methods such as gravure coating, gravure reverse coating, gravure offset coating, spin coating, roll coating, reverse roll coating, blade coating, dip coating, screen printing, and die coating. A transfer method can also be used to form a primer layer.

(2) Fingerprint Prevention Layer The display device member in this embodiment may have a fingerprint prevention layer 6 on the side of the functional layer 4 opposite to the resin layer 3, as shown in Fig. 5 for example. The fingerprint prevention layer makes it difficult for fingerprints to adhere and easy to wipe off.

There are no particular limitations on the material for the fingerprint prevention layer, so long as it is a material that can provide fingerprint resistance, and any common fingerprint prevention layer material can be used.

There are no particular limitations on the thickness of the fingerprint prevention layer, so long as it exhibits fingerprint resistance.

Methods for forming the fingerprint prevention layer include, for example, coating and vapor deposition.

6. Characteristics of the display device member The display device member in the present disclosure preferably has a total light transmittance of, for example, 80% or more, more preferably 85% or more, and even more preferably 88% or more. Such a high total light transmittance allows the display device member to have good transparency.

Here, the total light transmittance of the display device component can be measured in accordance with JIS K7361-1, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

The haze of the display device member in this disclosure is, for example, preferably 2.0% or less, more preferably 1.5% or less, and even more preferably 1.0% or less. Such a low haze allows the display device member to have good transparency.

Here, the haze of the display device member can be measured in accordance with JIS K-7136, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

The display device member in the present disclosure preferably has bending resistance. Specifically, when the display device member is subjected to the dynamic bending test described below, it is preferable that the display device member does not crack or break.

The dynamic bending test is performed as follows. As shown in FIG. 6(a), in the dynamic bending test, first, the short side 1C of the display device member 1 having a size of 20 mm×100 mm and the short side 1D opposite to the short side 1C are fixed by the fixing parts 21 arranged in parallel. Also, as shown in FIG. 6(a), the fixing parts 21 are slidable in the horizontal direction. Next, as shown in FIG. 6(b), the fixing parts 21 are moved so as to approach each other, so that the display device member 1 is deformed so as to be folded, and further, as shown in FIG. 6(c), the fixing parts 21 are moved to a position where the distance d between the two opposing short side parts 1C and 1D fixed by the fixing parts 21 of the display device member 1 becomes a predetermined value, and then the fixing parts 21 are moved in the opposite direction to eliminate the deformation of the display device member 1. By moving the fixing parts 21 as shown in FIG. 6(a) to (c), the display device member 1 can be folded 180°. In addition, by performing a dynamic bending test so that the bent portion 1E of the display device member 1 does not protrude from the lower end of the fixed portion 21 and controlling the distance when the fixed portion 21 is closest, the distance d between the two opposing short sides 1C, 1D of the display device member 1 can be set to a predetermined value. For example, if the distance d between the two opposing short sides 1C, 1D of the display device member 1 is 10 mm, the outer diameter of the bent portion 1E is considered to be 10 mm.

In the display device member, it is preferable that no cracks or breaks occur when a dynamic bending test is repeated 100,000 times so that the distance d between the opposing short sides 1C, 1D of the display device member 1 is 10 mm, and it is even more preferable that no cracks or breaks occur when the test is repeated 200,000 times.

In the dynamic bending test, the display device member may be bent so that the glass substrate is on the outside, or the display device member may be bent so that the glass substrate is on the inside, but in either case, it is preferable that the display device member does not crack or break.

In addition, when the static bending test described below is performed on the member for a display device, the opening angle θ after the static bending test is preferably 100° or more, and more preferably 130° or more.

The static bending test is performed as follows. First, as shown in FIG. 7(a), the short side 1C of the display device member 1 and the short side 1D facing the short side 1C are fixed by the fixing parts 22 arranged in parallel so that the distance d between the short side 1C and the short side 1D is 10 mm. Then, a static bending test is performed in which the display device member 1 is left in a folded state at 23°C for 240 hours. After that, as shown in FIG. 7(b), the fixing parts 22 are removed from the short side 1D after the static bending test to open the folded state, and the opening angle θ, which is the angle at which the display device member 1 naturally opens after 30 minutes at room temperature, is measured. Note that the larger the opening angle θ, the better the restorability, and the maximum opening angle is 180°.

In the static bending test, the display device component may be bent so that the glass substrate faces inward, or the display device component may be bent so that the glass substrate faces outward. In either case, the opening angle θ is preferably 100° or more, and more preferably 130° or more.

7. Use of display device member The display device member in the present disclosure can be used as a member arranged on the observer side of the display panel in a display device. The display device member in the present disclosure can be used in display devices used in electronic devices such as smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PIDs), and in-vehicle displays. In particular, the display device member in the present disclosure can be preferably used in flexible displays such as foldable displays, rollable displays, and bendable displays, and is more preferably used in foldable displays.

When the display device member of the present disclosure is placed on the surface of a display device, the surface on the glass substrate side faces the display panel, and the surface on the functional layer side faces outward.

The method for disposing the display device member of the present disclosure on the surface of the display device is not particularly limited, and examples include a method using an adhesive layer. As the adhesive layer, a known adhesive layer used for adhering display device members can be used.

II. Second embodiment A second embodiment of the display device member in the present disclosure has a glass substrate, a resin layer, a first functional layer, and a functional film in this order, and the functional film has an adhesive layer, a base layer, and a second functional layer in this order from the first functional layer side. The thickness of the glass substrate is 100 μm or less, the average value of the total thickness of the resin layer and the first functional layer is 10 μm or more and 60 μm or less, and the maximum value of the total thickness of the resin layer and the first functional layer is 60 μm or less.

8 is a schematic cross-sectional view showing an example of a display device member in this embodiment. As shown in FIG. 8, the display device member 1 has a glass substrate 2, a resin layer 3, a first functional layer 31, and a functional film 32 in this order, and the functional film 32 has an adhesive layer 33, a substrate layer 34, and a second functional layer 35 in this order from the first functional layer 31 side. The glass substrate 2 has a predetermined thickness. In addition, the average value of the total thickness of the resin layer 3 and the first functional layer 31 is within a predetermined range, and the maximum value T2 _max of the total thickness of the resin layer 3 and the first functional layer 31 is equal to or less than a predetermined value.

Here, when the resin layer 3 and the first functional layer 31 are formed on one surface of the glass substrate 2 by a coating method, the thicknesses of the ends of the resin layer 3 and the first functional layer 31 tend to increase due to surface tension, causing raised portions 11 to form at the ends of the resin layer 3 and the first functional layer 31. In the example shown in Fig. 8, the maximum value of the total thickness of the raised portions 11 of the resin layer 3 and the first functional layer 31 is the maximum value _T2max of the total thickness of the resin layer 3 and the first functional layer 31.

The display device member of this embodiment can achieve the same effects as the display device member of the first embodiment.

The following describes each component of the display device in this embodiment.

1. Thickness of the resin layer, the first functional layer, the functional film, and the second functional layer In this embodiment, the average value of the total thickness of the resin layer and the first functional layer can be 10 μm or more and 60 μm or less, preferably 25 μm or more and 55 μm or less, more preferably 30 μm or more and 50 μm or less. By the average value of the total thickness of the resin layer and the first functional layer being within the above range, it is possible to suppress the cracking of the glass substrate due to impact, improve the impact resistance, and suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer and the first functional layer when the display device member is bent, thereby improving the bending resistance. On the other hand, if the average value of the total thickness of the resin layer and the first functional layer is too small, the impact resistance may be reduced. In addition, if the average value of the total thickness of the resin layer and the first functional layer is too large, the bending resistance may be reduced.

In addition, in this embodiment, the maximum value of the total thickness of the resin layer and the first functional layer can be the same as the maximum value of the total thickness of the resin layer and the functional layer in the first embodiment described above.

Here, as described above, when the resin layer and the first functional layer are formed on one surface of the glass substrate by a coating method, the thickness of the ends of the resin layer and the first functional layer increases due to surface tension, and as shown in FIG. 8, for example, raised portions 11 tend to occur at the ends of the resin layer 3 and the first functional layer 31. In this case, the maximum value of the total thickness of the resin layer and the first functional layer is the maximum value of the total thickness of the raised portions of the resin layer and the first functional layer. In such a case, for example, when the planar shape of the resin layer and the first functional layer is rectangular or square, it is sufficient that the maximum value of the total thickness of the resin layer and the first functional layer satisfies the above range at the end of at least one of the four sides of the resin layer and the first functional layer.

Among these, for the same reasons as for the resin layer and the functional layer in the first embodiment, it is preferable that the maximum value of the total thickness of the resin layer and the first functional layer is in the above range at the ends of two opposing sides of the four sides of the resin layer and the first functional layer. Also, when the planar shape of the resin layer and the first functional layer is rectangular, it is preferable that the maximum value of the total thickness of the resin layer and the first functional layer is in the above range at the ends of two opposing long sides of the four sides of the resin layer and the first functional layer. Furthermore, for the reasons described above, it is preferable that the maximum value of the total thickness of the resin layer and the first functional layer is in the above range at the ends of two sides that are approximately parallel to the bending direction of the display device member of the four sides of the resin layer and the first functional layer.

In particular, it is preferable that the maximum total thickness of the resin layer and the first functional layer is within the above range at all ends of the four sides of the resin layer and the first functional layer. This can further improve bending resistance.

Methods for controlling the maximum value of the total thickness of the resin layer and the first functional layer to be within a predetermined range include, for example, a method of incorporating a leveling agent into the resin layer and the first functional layer, a method of forming the resin layer and the first functional layer on one side of the glass substrate to obtain a laminate and then cutting the laminate, and a method of transferring the resin layer and the first functional layer to one side of the glass substrate.

In addition, in this embodiment, the ratio of the maximum value of the total thickness of the resin layer and the first functional layer to the average value of the total thickness of the resin layer and the first functional layer can be the same as the ratio of the maximum value of the total thickness of the resin layer and the functional layer to the average value of the total thickness of the resin layer and the functional layer in the first embodiment described above.

Here, the total thickness of the resin layer and the first functional layer can be measured by microscopic cross-sectional observation. In microscopic cross-sectional observation, for example, a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM) is used to observe the cross section of the display device member in the thickness direction, and the total thickness of the resin layer and the first functional layer can be determined from the obtained image.

The average value of the total thickness of the resin layer and the first functional layer is the arithmetic mean value of the total thickness at any 10 points in the area other than the raised portion when the resin layer 3 and the first functional layer 31 have a raised portion 11, for example, as shown in FIG. 8. On the other hand, when the resin layer and the first functional layer do not have a raised portion, the average value of the total thickness of the resin layer and the first functional layer can be the arithmetic mean value of the total thickness at any 10 points.

In addition, the maximum value of the total thickness of the resin layer and the first functional layer is the maximum value of the total thickness of the raised portion of the resin layer and the first functional layer when the resin layer 3 and the first functional layer 31 have a raised portion 11, for example as shown in FIG. 8. On the other hand, when the resin layer and the first functional layer do not have a raised portion, the maximum value of the total thickness of the resin layer and the first functional layer can be the maximum value of the total thickness at any 10 points.

In addition, in this embodiment, the average thickness of the first functional layer can be the same as the average thickness of the functional layer in the first embodiment described above.

In addition, the ratio of the average thickness of the first functional layer to the average total thickness of the resin layer and the first functional layer can be the same as the ratio of the average thickness of the functional layer to the average total thickness of the resin layer and the functional layer in the first embodiment described above.

Here, the method for measuring the thickness of the first functional layer can be the same as the method for measuring the total thickness of the resin layer and the first functional layer described above.

When the first functional layer 31 has a raised portion 11, as shown in FIG. 8, the average thickness of the first functional layer is the arithmetic mean value of the thicknesses at any 10 points in the area other than the raised portion. On the other hand, when the first functional layer does not have a raised portion, the average thickness of the first functional layer can be the arithmetic mean value of the thicknesses at any 10 points.

The average thickness of the resin layer is not particularly limited as long as it satisfies the average value of the total thickness of the resin layer and the first functional layer and the average thickness of the first functional layer, and can be the same as the average thickness of the resin layer in the first embodiment.

Here, the method for measuring the thickness of the resin layer can be the same as the method for measuring the total thickness of the resin layer and the first functional layer described above.

The average thickness of the resin layer is the arithmetic mean value of the thicknesses at any 10 points in the area other than the raised portion when the resin layer 3 has a raised portion 11, as shown in FIG. 8, for example. On the other hand, when the resin layer does not have a raised portion, the average thickness of the resin layer can be the arithmetic mean value of the thicknesses at any 10 points.

In this embodiment, the resin layer and the first functional layer have a raised portion at the end, and the cross-sectional shape of the raised portion is approximated to a triangle, and the height of the triangle is the difference between the maximum value of the total thickness of the resin layer and the first functional layer and the average value of the total thickness of the resin layer and the first functional layer, and the length of the base of the triangle is the distance from the end of the resin layer and the first functional layer to the position where the total thickness of the raised portion of the resin layer and the first functional layer is the average value of the total thickness of the resin layer and the first functional layer. The area of the triangle is, for example, preferably 0.08 mm ² or less, more preferably 0.07 mm ² or less, and even more preferably 0.06 mm ² or less. The reason why the area of the triangle is preferably in the above range is the same as the case where the cross-sectional shape of the raised portion of the resin layer and the functional layer in the first embodiment is approximated to a triangle.

The explanation for approximating the cross-sectional shape of the raised portion of the resin layer and the first functional layer to a triangle can be the same as the explanation for approximating the cross-sectional shape of the raised portion of the resin layer and the functional layer to a triangle in the first embodiment above.

In addition, in this embodiment, the average thickness of the second functional layer is, for example, preferably 5 μm or more and less than 15 μm, and more preferably 7 μm or more and 13 μm or less. The reason why the average thickness of the second functional layer is preferably in the above range is the same as the reason why the average thickness of the first functional layer is preferably in a predetermined range.

Here, the method for measuring the thickness of the second functional layer can be the same as the method for measuring the combined thickness of the resin layer and the first functional layer described above. Furthermore, the average thickness of the second functional layer can be the arithmetic mean value of the thicknesses at any 10 points.

In this embodiment, the average thickness of the functional film is, for example, preferably 20 μm or more and 150 μm or less, more preferably 35 μm or more and 135 μm or less, and even more preferably 50 μm or more and 120 μm or less. If the average thickness of the functional film is too large, the bending resistance may decrease. If the average thickness of the functional film is too small, the thickness of the second functional layer may become relatively thin, and the characteristics of the second functional layer may decrease. For example, when the second functional layer is a hard coat layer, if the thickness of the second functional layer is too thin, sufficient scratch resistance may not be obtained.

Here, the method for measuring the thickness of the functional film can be the same as the method for measuring the combined thickness of the resin layer and the first functional layer described above. Furthermore, the average thickness of the functional film can be the arithmetic mean value of the thicknesses at any 10 points.

2. Resin Layer The resin layer in this embodiment can be the same as the resin layer in the first embodiment, and therefore a description thereof will be omitted here.

3. First Functional Layer The first functional layer in this embodiment can be the same as the functional layer in the first embodiment, and therefore a description thereof will be omitted here.

4. Functional Film The functional film in this embodiment has, in this order from the first functional layer side, an adhesive layer, a base layer, and a second functional layer.

(1) Second Functional Layer The second functional layer in this embodiment is a layer disposed on the opposite side of the base layer to the adhesive layer. An example of the second functional layer is a hard coat layer.

The hard coat layer can be the same as the hard coat layer constituting the functional layer in the first embodiment described above, so a description thereof will be omitted here.

Regarding the characteristics of the hard coat layer, pencil hardness is measured on the functional film alone, and pencil hardness is measured on the surface of the functional film on the hard coat layer side.

(2) Substrate Layer The substrate layer in this embodiment is a layer that supports the second functional layer.

The substrate layer has transparency. Specifically, the total light transmittance of the substrate layer is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more.

Here, the total light transmittance of the substrate layer can be measured in accordance with JIS K7361-1, for example, using a haze meter HM150 manufactured by Murakami Color Research Laboratory. The same method can be used to measure the total light transmittance of other layers.

For example, a resin substrate can be used as the substrate layer, and specific examples of the resin substrate include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), aramid, polyimide, polyamideimide, etc.

The thickness of the substrate layer can be, for example, 20 μm or more and 120 μm or less. If the substrate layer is too thick, the bending resistance may be impaired. On the other hand, if the substrate layer is too thin, it may be difficult to handle.

(3) Adhesive Layer The adhesive layer in this embodiment is a layer for bonding the functional film to the first functional layer.

The adhesive layer has transparency. Specifically, the total light transmittance of the adhesive layer is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more.

Examples of adhesives used in the adhesive layer include adhesives such as OCA (Optical Clear Adhesive) and photosensitive adhesives.

The thickness of the adhesive layer is preferably, for example, 1 μm or more and 100 μm or less. If the adhesive layer is too thick, there is a risk that the bending resistance will be impaired. On the other hand, if the adhesive layer is too thin, there is a risk that the adhesiveness will not be guaranteed and the adhesive layer will peel off.

5. Glass Substrate The glass substrate in this embodiment can be the same as the glass substrate in the first embodiment, and therefore a description thereof will be omitted here.

6. Other Configurations In addition to the above-mentioned layers, the display device member in this embodiment may have other layers as necessary. Examples of the other layers include a primer layer.

The display device member in this embodiment may have a primer layer 5 between the glass substrate 2 and the resin layer 3, as shown in FIG. 9, for example. The primer layer can improve the adhesion between the glass substrate and the resin layer.

The primer layer can be the same as the primer layer in the first embodiment above, so a description of it will be omitted here.

7. Member for Display Device The characteristics and uses of the member for a display device in this embodiment can be similar to those of the member for a display device in the first embodiment, and therefore a description thereof will be omitted here.

III. Third embodiment A third embodiment of the display device member of the present disclosure includes a glass substrate, a resin layer, and a functional film in this order, and the functional film includes, from the resin layer side, an adhesive layer, a substrate layer, and a functional layer in this order. The thickness of the glass substrate is 100 μm or less, the average thickness of the resin layer is 10 μm or more and 60 μm or less, and the maximum thickness of the resin layer is 60 μm or less.

Fig. 10 is a schematic cross-sectional view showing an example of a display device member in this embodiment. As shown in Fig. 10, the display device member 1 has a glass substrate 2, a resin layer 3, and a functional film 32 in this order, and the functional film 32 has an adhesive layer 33, a substrate layer 34, and a functional layer 36 in this order from the resin layer 3 side. The glass substrate 2 has a predetermined thickness. In addition, the average thickness of the resin layer 3 is within a predetermined range, and the maximum thickness T3 _max of the resin layer 3 is equal to or less than a predetermined value.

Here, when the resin layer 3 is formed on one surface of the glass substrate 2 by a coating method, the thickness of the end portion of the resin layer 3 increases due to surface tension, and a raised portion 11 tends to be generated at the end portion of the resin layer 3. In the example shown in Fig. 10, the maximum thickness of the raised portion 11 of the resin layer 3 is the maximum thickness _T3max of the resin layer 3.

The display device member of this embodiment can achieve the same effects as the display device member of the first embodiment.

The following describes each component of the display device in this embodiment.

1. Thickness of the resin layer, functional film and functional layer In this embodiment, the average thickness of the resin layer can be 10 μm or more and 60 μm or less, preferably 25 μm or more and 55 μm or less, more preferably 30 μm or more and 50 μm or less. By having the average thickness of the resin layer within the above range, it is possible to suppress the cracking of the glass substrate due to impact, improve the impact resistance, and suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer when the display device member is bent, thereby improving the bending resistance. On the other hand, if the average thickness of the resin layer is too small, the impact resistance may decrease. Also, if the average thickness of the resin layer is too large, the bending resistance may decrease.

In addition, in this embodiment, the maximum thickness of the resin layer is 60 μm or less, and preferably 55 μm or less. By having the maximum thickness of the resin layer within the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer when the display device member is bent, and to improve bending resistance. On the other hand, if the maximum thickness of the resin layer is too large, there is a risk of reduced bending resistance.

As described above, when a resin layer is formed on one surface of a glass substrate by a coating method, the surface tension causes the thickness of the end of the resin layer to increase, and as shown in FIG. 10, for example, a raised portion 11 tends to occur at the end of the resin layer 3. In this case, the maximum thickness of the resin layer is the maximum thickness of the raised portion of the resin layer. In such a case, for example, when the resin layer has a rectangular or square shape in plan view, it is sufficient that the maximum thickness of the resin layer at the end of at least one of the four sides of the resin layer falls within the above range.

Among these, for the same reasons as for the resin layer and functional layer in the first embodiment, it is preferable that the maximum thickness of the resin layer is within the above range at the ends of two opposing sides of the resin layer. Also, when the resin layer has a rectangular shape in plan view, it is preferable that the maximum thickness of the resin layer is within the above range at the ends of two opposing long sides of the resin layer. Furthermore, for the reasons described above, it is preferable that the maximum thickness of the resin layer is within the above range at the ends of two sides of the resin layer that are approximately parallel to the bending direction of the display device member.

In particular, it is preferable that the maximum thickness of the resin layer is within the above range at all four ends of the resin layer. This can further improve bending resistance.

Methods for controlling the maximum thickness of the resin layer to fall within a predetermined range include, for example, a method of incorporating a leveling agent into the resin layer, a method of forming a resin layer on one side of a glass substrate to obtain a laminate and then cutting the laminate, and a method of transferring a resin layer to one side of a glass substrate.

In addition, in this embodiment, the ratio of the maximum thickness of the resin layer to the average thickness of the resin layer is, for example, preferably 130% or less, and more preferably 125% or less. By having the above ratio within the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer when the display device member is bent, and to improve bending resistance. On the other hand, if the above ratio is too large, there is a risk of reduced bending resistance.

Here, the thickness of the resin layer can be measured by microscopic cross-sectional observation. In microscopic cross-sectional observation, for example, a transmission electron microscope (TEM), a scanning electron microscope (SEM), or a scanning transmission electron microscope (STEM) is used to observe the cross section of the display device member in the thickness direction, and the thickness of the resin layer can be determined from the obtained image.

When the resin layer 3 has a raised portion 11 as shown in FIG. 10, the average thickness of the resin layer is the arithmetic mean value of the total thickness at any 10 points in the area other than the raised portion. On the other hand, when the resin layer does not have a raised portion, the average thickness of the resin layer can be the arithmetic mean value of the thickness at any 10 points.

In addition, when the resin layer 3 has a raised portion 11 as shown in FIG. 10, the maximum thickness of the resin layer is the maximum thickness of the raised portion of the resin layer. On the other hand, when the resin layer does not have a raised portion, the maximum thickness of the resin layer can be the maximum value of the thicknesses at any 10 points.

In this embodiment, the resin layer has a raised portion at the end, and the cross-sectional shape of the raised portion is approximated to a triangle, and the height of the triangle is the difference between the maximum thickness of the resin layer and the average thickness of the resin layer, and the length of the base of the triangle is the distance from the end of the resin layer to the position where the thickness of the raised portion of the resin layer becomes the average thickness of the resin layer. The area of the triangle is preferably, for example, 0.08 mm ² or less, more preferably 0.07 mm ² or less, and even more preferably 0.06 mm ² or less. By having the area of the triangle in the above range, it is possible to suppress the occurrence of cracks, whitening, wrinkles, etc. in the resin layer when the display device member is bent, and to improve the bending resistance. On the other hand, if the area of the triangle is too large, the bending resistance may be reduced.

Here, a case where the cross-sectional shape of the raised portion of the resin layer is approximated to a triangle will be described with reference to Fig. 11. As shown in Fig. 11, the cross-sectional shape of the raised portion 11 of the resin layer 3 is approximated to a triangle 15 indicated by a dashed line. The height H3 of the triangle 15 is the difference between the maximum thickness _T3max of the resin layer 3 and the average thickness _T3ave of the resin layer 3. The length D3 of the base of the triangle 15 is the distance from the end of the resin layer 3 to a position P3 where the thickness of the raised portion 11 of the resin layer 3 becomes the average thickness _T3ave of the resin layer 3.

Note that position P3 where the thickness of raised portion 11 of resin layer 3 becomes the average thickness T3 _ave of resin layer 3 is a position in raised portion 11 where the thickness of raised portion 11 of resin layer 3 changes from the maximum thickness T3 _max of resin layer 3 as it becomes farther from the end of resin layer 3 and becomes the average thickness T3 _ave of resin layer 3.

In addition, with regard to the position from the end of the resin layer where the thickness of the raised portion of the resin layer becomes the average thickness of the resin layer, if there are multiple peaks in the thickness of the resin layer 3 in the raised portion 11 of the resin layer 3 as shown in FIG. 11 , and the thickness of the raised portion 11 of the resin layer 3 changes from the maximum thickness T3 _max of the resin layer 3 with increasing distance from the end of the resin layer 3, and there are multiple positions P3, P4 where the thickness becomes the average thickness T3 _ave of the resin layer 3, then of these positions P3, P4, the position P3 farthest from the end of the resin layer 3 is used.

In addition, in this embodiment, the average thickness of the functional layer can be the same as the average thickness of the second functional layer in the second embodiment described above.

In addition, in this embodiment, the average thickness of the functional film can be the same as the average thickness of the functional film in the second embodiment described above.

2. Resin Layer The resin layer in this embodiment can be the same as the resin layer in the first embodiment, and therefore a description thereof will be omitted here.

3. Functional Film The functional film in this embodiment has, in this order from the resin layer side, an adhesive layer, a base layer, and a functional layer.

The functional layer, base layer, and adhesive layer can be similar to the second functional layer, base layer, and adhesive layer that constitute the functional film in the second embodiment described above, and therefore will not be described here.

4. Glass Substrate The glass substrate in this embodiment can be the same as the glass substrate in the first embodiment, and therefore a description thereof will be omitted here.

5. Other Configurations In addition to the above-mentioned layers, the display device member in this embodiment may have other layers as necessary. Examples of the other layers include a primer layer.

The display device member in this embodiment may have a primer layer 5 between the glass substrate 2 and the resin layer 3, as shown in FIG. 13, for example. The primer layer can improve the adhesion between the glass substrate and the resin layer.

The primer layer can be the same as the primer layer in the first embodiment above, so a description of it will be omitted here.

6. Member for Display Device The characteristics and uses of the member for a display device in this embodiment can be similar to those of the member for a display device in the first embodiment, and therefore a description thereof will be omitted here.

B. Display Device A display device according to the present disclosure includes a display panel and the above-described member for a display device, which is disposed on the viewer's side of the display panel.

Fig. 14 is a schematic cross-sectional view showing an example of a display device according to the present disclosure. As shown in Fig. 14, a display device 40 includes a display panel 41 and a member for a display device 1 arranged on the viewer side of the display panel 41. In the display device 40, the member for a display device 1 is used as a member arranged on the surface of the display device 40, and an adhesive layer 42 is arranged between the member for a display device 1 and the display panel 41.

The display device components in this disclosure can be similar to the display device components described above.

Display panels in this disclosure include, for example, display panels used in display devices such as liquid crystal display devices, organic EL display devices, and LED display devices.

The display device of the present disclosure can have a touch panel member between the display panel and the display device member.

The display device in the present disclosure is preferably a flexible display. In particular, the display device in the present disclosure is preferably foldable. In other words, the display device in the present disclosure is more preferably a foldable display. Since the display device in the present disclosure has the above-mentioned display device member, it has excellent impact resistance and bending resistance, and is suitable as a flexible display, and further as a foldable display.

C. Electronic Device An electronic device in the present disclosure includes the display device described above.

The electronic devices in this disclosure are not particularly limited as long as they are equipped with the above-mentioned display device, and examples include smartphones, tablet terminals, wearable terminals, personal computers, televisions, digital signage, public information displays (PIDs), in-vehicle displays, etc.

This disclosure is not limited to the above-mentioned embodiments. The above-mentioned embodiments are merely examples, and anything that has substantially the same configuration as the technical ideas described in the claims of this disclosure and provides similar effects is included within the technical scope of this disclosure.

The present disclosure will be further explained below with reference to examples and comparative examples. In the following, the hard coat layer formed on the resin layer will be referred to as the first hard coat layer, and the hard coat layer constituting the functional film will be referred to as the second hard coat layer.

[Comparative Example 1]
(1) Formation of Primer Layer A primer layer composition was prepared by blending the components shown below.
<Primer layer composition>
Bisphenol A type solid epoxy resin (jER1256B40 manufactured by Mitsubishi Chemical) 28 parts by mass Bisphenol A novolac type solid epoxy resin (jER157S65B80 manufactured by Mitsubishi Chemical) 5 parts by mass 2-ethyl-4-methylimidazole (manufactured by Tokyo Chemical Industry Co., Ltd.) 1 part by mass Solvent (MEK) 11 parts by mass

A chemically strengthened glass substrate with a thickness of 70 μm was prepared, and the primer layer composition was applied to the glass substrate to a predetermined thickness, and dried at 80°C for 3 minutes and at 150°C for 60 minutes to form a primer layer with a thickness of 0.3 μm.

(2) Formation of Resin Layer With reference to Synthesis Example 1 of WO 2014/046180, a tetracarboxylic dianhydride represented by the following chemical formula was synthesized.

A solution of dehydrated N,N-dimethylacetamide (DMAc) (1833.2 g) and 2,2'-bis(trifluoromethyl)benzidine (TFMB) (138.48 g) was placed in a 5 L separable flask, and the liquid temperature was controlled to 30°C. Tetracarboxylic acid dianhydride (TMPBPTME) (176.70 g) represented by the above chemical formula was gradually added so that the temperature rise was 2°C or less, and the mixture was stirred with a mechanical stirrer for 30 minutes. Pyromellitic dianhydride (PMDA) (64.20 g) was gradually added in several portions so that the temperature rise was 2°C or less, synthesizing a polyimide precursor solution (solid content 18% by mass) in which the polyimide precursor was dissolved. The molar ratio of the tetracarboxylic dianhydride TMPBPTME and PMDA (TMPBPTME:PMDA) used in the polyimide precursor was 90:10. The weight average molecular weight of the polyimide precursor was 75,000.

Under a nitrogen atmosphere, the above polyimide precursor solution (2162 g) was added to a 5 L separable flask, cooled to room temperature. Dehydrated N,N-dimethylacetamide (432 g) was added and stirred until homogenous. Next, the catalysts pyridine (6.622 g) and acetic anhydride (213.67 g) were added and stirred at room temperature for 24 hours to synthesize a polyimide solution.

N,N-dimethylacetamide (DMAc) (2000 g) was added to the resulting polyimide solution and stirred until homogenous. Next, the polyimide solution was divided into three equal parts and transferred to 5 L beakers, and isopropyl alcohol (3500 g) was gradually added to each beaker to obtain a white slurry. The above slurry was transferred onto a Buchner funnel and filtered, then washed by pouring over with isopropyl alcohol (total 9000 g), and then filtered. This process was repeated three times, and the mixture was dried at 110°C using a vacuum dryer to obtain polyimide (polyimide powder). The weight average molecular weight of the polyimide measured by GPC was 100,000.

N,N-dimethylacetamide (DMAc) was added to the polyimide so that the solid content of the polyimide was 12% by mass, and a polyimide varnish (resin composition) was prepared with a polyimide content of 12% by mass in the varnish. The viscosity of the polyimide varnish (resin composition) (solid content concentration 12% by mass) at 25°C was 15,000 cps.

The polyimide varnish (resin composition) was applied to a specified thickness on the primer layer and dried at 100°C for 10 minutes, 150°C for 10 minutes, and 230°C for 30 minutes to form a resin layer with a thickness of 10 μm.

(3) Formation of First Hard Coat Layer A curable resin composition for a hard coat layer was prepared by blending the components so as to obtain the composition shown below.
<Curable resin composition for hard coat layer>
Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (M403, manufactured by Toa Gosei Co., Ltd.) 25 parts by mass Dipentaerythritol EO-modified hexaacrylate (A-DPH-6E, manufactured by Shin-Nakamura Chemical Co., Ltd.) 25 parts by mass Non-standard silica fine particles (average particle size 25 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.) 50 parts by mass (solid equivalent)
Photopolymerization initiator (Irg184) 4 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent)
UV absorber 1 (DAINSORB P6, manufactured by Daiwa Kasei) 3 parts by weight Solvent (MIBK) 150 parts by weight

The above-mentioned curable resin composition for the hard coat layer was applied to the above-mentioned resin layer to a predetermined thickness, dried at 80°C for 3 minutes, and then cured by ultraviolet irradiation to form a hard coat layer with a thickness of 5 μm. This resulted in a member for a display device.

[Examples 1 to 8 and Comparative Examples 2 to 5]
A member for a display device was produced in the same manner as in Comparative Example 1, except that the thickness of the resin layer and the thickness of the first hard coat layer were set to the thicknesses shown in Table 1 below.

[Evaluation 1]
(1) Steel wool resistance (scratch resistance)
A steel wool test was carried out on the surface of the first hard coat layer side of the display device member to evaluate the scratch resistance. Specifically, the display device member cut into a size of 10 cm x 5 cm was fixed on a glass plate with cellophane tape manufactured by Nichiban Co., Ltd. so as not to bend or wrinkle, and then rubbed 2500 times back and forth at a speed of 50 mm/sec with a load of 9.8 N using steel wool #0000 (Bonstar #0000 manufactured by Nippon Steel Wool Co., Ltd.). Thereafter, the presence or absence of scratches on the surface of the display device member was visually confirmed. The evaluation criteria were as follows.
A: No scratches were found.
F: Scratches were observed.

(2) Dynamic Bending Test A dynamic bending test was performed on the display member to evaluate its bending resistance. Specifically, a display member having a size of 20 mm x 100 mm was fixed to a durability tester (product name "DLDMLH-FS", manufactured by Yuasa System Devices Co., Ltd.) at the short side (20 mm) of the display member with a fixing part, and the minimum distance d between the two opposing short sides was adjusted to 10 mm as shown in FIG. 6(c), and a dynamic bending test was performed 100,000 times in which the surface of the display member was folded by 180°. At this time, the display member was folded so that the surface on the first hard coat layer side was the outside and the surface on the glass substrate side was the inside. The evaluation criteria were as follows.
A: No cracks or whitening occurred in the resin layer or the hard coat layer.
F: Cracks or whitening occurred in the resin layer or hard coat layer.

(3) Pen drop test (impact test)
An impact test was performed on the display device member. Specifically, first, a 50 μm thick optical adhesive film (OCA) and a 100 μm thick PET film were attached in this order to the surface of the glass substrate of the display device member to prepare a test laminate. The test laminate was placed on a metal plate so that the PET film side of the test laminate was in contact with the metal plate having a thickness of 30 mm. Next, a pen was dropped on the test laminate from the test height with its tip facing down. A Zebra Blen 0.5BAS88-BK (weight 12 g, pen tip 0.5 mmφ) was used as the pen. The evaluation criteria were as follows.
A: The minimum test height at which cracks occurred in the glass substrate was 30 cm or more.
B: The minimum test height at which a crack occurred in the glass substrate was 20 cm or more and less than 30 cm.
C: The minimum test height at which the glass substrate cracked was less than 20 cm.

[Examples 9 to 12 and Comparative Examples 6 to 7]
A member for a display device was produced in the same manner as in Comparative Example 1, except that the thicknesses of the resin layer and the first hard coat layer were set to the thicknesses shown in Table 2 below.

[Evaluation 2]
(1) Total thickness of resin layer and first hard coat layer Using a stylus film thickness gauge (Mitutoyo LGK-0110-542-158), the surface of the display device member was measured with a stylus at equal intervals of 1 mm, and the average and maximum values of the total thickness of the resin layer and the first hard coat layer were obtained from the obtained film thickness profile data. Furthermore, the cross-sectional shapes of the raised parts at the ends of the resin layer and the first hard coat layer were approximated to a triangle, and the area of the triangle was obtained. Figures 15(a) and (b) show the distribution of the total thickness of the resin layer and the first hard coat layer.

(2) Dynamic Bending Test A dynamic bending test was carried out in the same manner as in Evaluation 1 above to evaluate bending resistance.

(3) Pen drop test (impact test)
The impact test was carried out in the same manner as in Evaluation 1 above.

From Tables 1 and 2, it was confirmed that when a display device member has a glass substrate, a resin layer, and a functional layer in this order, it is possible to achieve both good bending resistance and impact resistance by setting the average value of the total thickness of the resin layer and the functional layer and the maximum value of the total thickness of the resin layer and the functional layer within a specified range.

[Comparative Example 8]
(1) Preparation of Hard Coat Film The components were mixed so as to obtain the composition shown below, thereby preparing a curable resin composition for a hard coat layer.
<Curable resin composition for hard coat layer>
Mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate (M403, manufactured by Toa Gosei Co., Ltd.) 25 parts by mass Dipentaerythritol EO-modified hexaacrylate (A-DPH-6E, manufactured by Shin-Nakamura Chemical Co., Ltd.) 25 parts by mass Non-standard silica fine particles (average particle size 25 nm, manufactured by JGC Catalysts and Chemicals Co., Ltd.) 50 parts by mass (solid equivalent)
Photopolymerization initiator (Irg184) 4 parts by mass Fluorine-based leveling agent (F568, manufactured by DIC Corporation) 0.2 parts by mass (solid equivalent)
UV absorber 1 (DAINSORB P6, manufactured by Daiwa Kasei) 3 parts by weight Solvent (MIBK) 150 parts by weight

A 50 μm thick PET film (Toyobo Co., Ltd., product name A4100) was prepared, and the above-mentioned hard coat layer curable resin composition was applied onto the PET film using a bar coater. The coating was then dried at 100°C for 3 minutes and cured by irradiating with 200 mJ of ultraviolet light to form a second hard coat layer with a thickness of 10 μm. This resulted in a hard coat film.

(2) Formation of primer layer, resin layer, and first hard coat layer In Comparative Example 1, except that the thickness of the resin layer and the thickness of the first hard coat layer were set to the thicknesses shown in Table 2 below, a primer layer, a resin layer, and a first hard coat layer were formed on a glass substrate in the same manner as in Comparative Example 1, to obtain a laminate.

(3) Preparation of a member for a display device The surface of the first hard coat layer of the laminate was bonded to the surface of the PET film of the hard coat film using an acrylic adhesive film (manufactured by 3M, product name 8146-2) having a thickness of 50 μm. This resulted in a member for a display device.

[Examples 13 to 14 and Comparative Example 9]
A member for a display device was produced in the same manner as in Comparative Example 8, except that the thickness of the resin layer and the thickness of the first hard coat layer were set to the thicknesses shown in Table 3 below.

[Comparative Example 10]
A hard coat film was prepared in the same manner as in Comparative Example 8. The glass substrate used in Comparative Example 1 was also prepared. Next, the glass substrate and the PET film side surface of the hard coat film were bonded together using an acrylic adhesive film (manufactured by 3M, product name 8146-2) having a thickness of 50 μm. This resulted in a display device member being obtained.

[Evaluation 3]
(1) Total Thickness of Resin Layer and First Hard Coat Layer As in the above Evaluation 2, the average value and maximum value of the total thickness of the resin layer and the first hard coat layer were obtained, and further, the cross-sectional shapes of the raised portions at the ends of the resin layer and the first hard coat layer were approximated to a triangle, and the area of the triangle was obtained.

(2) Dynamic Bending Test A dynamic bending test was carried out in the same manner as in Evaluation 1 above to evaluate bending resistance.

(3) Pen drop test (impact test)
An impact test was carried out in the same manner as in the above Evaluation 1. The evaluation criteria were as follows.
AA: The minimum test height at which a crack occurs in the glass substrate is 40 cm or more.
A: The minimum test height at which a crack occurred in the glass substrate was 30 cm or more and less than 40 cm.
B: The minimum test height at which a crack occurred in the glass substrate was 20 cm or more and less than 30 cm.
C: The minimum test height at which the glass substrate cracked was less than 20 cm.

From Table 3, it was confirmed that when the display device component has a glass substrate, a resin layer, a first functional layer, and a functional film in this order, and the functional film has an adhesive layer, a substrate layer, and a second functional layer in this order from the first functional layer side, by setting the average value of the total thickness of the resin layer and the first functional layer and the maximum value of the total thickness of the resin layer and the first functional layer within a predetermined range, it is possible to achieve both good bending resistance and impact resistance. Note that, since Comparative Example 8 has the same evaluation in the pen drop test as Comparative Example 10, it is believed that the effect of achieving both bending resistance and impact resistance was achieved by controlling the distribution of the total thickness of the resin layer and the first functional layer.

[Comparative Example 12]
(1) Preparation of Hard Coat Film A hard coat film was prepared in the same manner as in Comparative Example 8.

(2) Formation of Resin Layer In Comparative Example 1, except that the first hard coat layer was not formed and the thickness of the resin layer was set to the thickness shown in Table 3 below, a primer layer and a resin layer were formed on a glass substrate in the same manner as in Comparative Example 1, to obtain a laminate.

(3) Preparation of a display member The resin layer side of the laminate and the PET film side of the hard coat film were bonded together using an acrylic adhesive film (manufactured by 3M, product name 8146-2) having a thickness of 50 μm to obtain a display member.

[Evaluation 4]
(1) Total Thickness of Resin Layer and First Hard Coat Layer As in Evaluation 2 above, the average thickness and maximum thickness of the resin layer were determined, and the cross-sectional shape of the raised portion at the end of the resin layer was approximated to a triangle to determine the area of the triangle.

(2) Dynamic Bending Test A dynamic bending test was carried out in the same manner as in Evaluation 1 above to evaluate bending resistance.

(3) Pen drop test (impact test)
An impact test was carried out in the same manner as in the above Evaluation 1. The evaluation criteria were the same as those in the above Evaluation 3.

From Table 4, it was confirmed that when the display device component has a glass substrate, a resin layer, and a functional film in that order, and the functional film has an adhesive layer, a substrate layer, and a second functional layer in that order from the resin layer side, it is possible to achieve both good bending resistance and impact resistance by setting the average thickness and maximum thickness of the resin layer within a specified range. Note that, since Comparative Example 11 had the same evaluation in the pen drop test as Comparative Example 10 above, it is believed that the effect of achieving both bending resistance and impact resistance was achieved by controlling the thickness distribution of the resin layer.

REFERENCE SIGNS LIST 1: Display device member 2: Glass substrate 3: Resin layer 4: Functional layer 5: Primer layer 6: Fingerprint prevention layer 11: Raised portion 31: First functional layer 32: Functional film 33: Adhesive layer 34: Substrate layer 35: Second functional layer 36: Functional layer 40: Display device 41: Display panel

Claims (7)

A display device member having a glass substrate, a resin layer, a first functional layer, and a functional film in this order, the functional film having, from the first functional layer side, an adhesive layer, a substrate layer, and a second functional layer,
The thickness of the glass substrate is 100 μm or less,
The average total thickness of the resin layer and the first functional layer is 10 μm or more and 60 μm or less, and the maximum total thickness of the resin layer and the first functional layer is 60 μm or less ,
The composite elastic modulus of the resin layer is 4.7 GPa or more and 20 GPa or less,
The average thickness of the functional film is 20 μm or more and 150 μm or less,
The member for a display device , wherein the first functional layer and the second functional layer are hard coat layers . 2. The member for a display device according to claim 1 , wherein the first functional layer has an average thickness of 5 μm or more and less than 15 μm, and the second functional layer has an average thickness of 5 μm or more and less than 15 μm. 3. A member for a display device according to claim 1 or 2 , wherein a ratio of a maximum value of a total thickness of the resin layer and the first functional layer to an average value of a total thickness of the resin layer and the first functional layer is 132% or less. the resin layer and the first functional layer have raised portions at their ends,
A member for a display device described in any one of claims 1 to 3, wherein when the cross-sectional shape of the raised portion is approximated to a triangle, the height of the triangle is the difference between the maximum value of the total thickness of the resin layer and the first functional layer and the average value of the total thickness of the resin layer and the first functional layer, and the length of the base of the triangle is the distance from the end of the resin layer and the first functional layer to a position where the total thickness of the raised portion of the resin layer and the first functional layer becomes the average value of the total thickness of the resin layer and the first functional layer , the area of the triangle is 0.08 ^mm2 or less. 5. The member for a display device according to claim 3, wherein a ratio of an average thickness of the first functional layer to an average total thickness of the resin layer and the first functional layer is 10% or more and 65% or less. A display panel;
A member for a display device according to any one of claims 1 to 5 , which is disposed on a viewer side of the display panel;
A display device comprising: An electronic device comprising the display device according to claim 6 .

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