JP7052358B2 - Wire grid polarizing plate and its manufacturing method - Google Patents

Description

The present invention relates to a wire grid polarizing plate used as a member of various optical devices such as a display device, a projector, a measuring device, and a camera, and a method for manufacturing the same.

Conventionally, various configurations using a polarizing plate have been proposed for an image display device. For example, in a liquid crystal display device, a liquid crystal display panel is formed by arranging linear polarizing plates on both sides of a liquid crystal cell in which a liquid crystal material is sandwiched between glass plates on which transparent electrodes are arranged. Further, a linear polarizing plate having a high reflectance of a specific polarizing component is arranged on the backlight side of the liquid crystal display panel to improve the utilization efficiency of the backlight. Further, in an organic EL display device or the like, a circular polarizing plate in which a linear polarizing plate and a 1/4 wave plate are laminated is arranged on the viewing surface side of an image display panel to provide a function of preventing reflection of external light. There is.

As the above-mentioned polarizing plate, an adsorption-oriented polarizing plate formed by impregnating polyvinyl alcohol (PVA) with iodine or the like and then stretching it and stretching it in one direction is usually used. From the viewpoint of thickness and light utilization efficiency, a polarizing plate that replaces the adsorption-oriented polarizing plate has been studied. As a typical example thereof, a display device using a wire grid polarizing plate formed by patterning a metal film such as aluminum in a grid pattern by etching or the like has been proposed (for example, Patent Documents 1 and 2).

The wire grid (WG) polarizing plate has a structure in which a grid pattern of a metal film such as aluminum is formed on a transparent substrate such as glass or film that is transparent to the wavelength range used, and has a grid period. By making it sufficiently smaller than the wavelength, the polarization in which the vibration direction of the electric field passes through the TM wave component (TM polarization) perpendicular to the longitudinal direction (extending direction) of the grid and reflects the parallel TE wave component (TE polarization). It becomes a board. Therefore, the TM light transmittance is high,
A large extinction ratio = TM light transmittance / TE light transmittance is the first optical characteristic required for a wire grid polarizing plate.

FIG. 9 shows an example of a liquid crystal display device 300 including wire grid polarizing plates 37 and 47. The liquid crystal display device 300 includes a liquid crystal layer 50 in which a color filter substrate 30 and a TFT array substrate 40 having a TFT array portion 42 including a TFT array and pixel electrodes on one side of a transparent substrate 41 are enclosed in a liquid crystal composition. It is pasted together via. Further, the wire grid polarizing plates 37 and 47 are bonded to the visible surface side of the color filter substrate 30 and the backlight side of the TFT array substrate 40 via the adhesive layers 36 and 46, respectively (note that the wire grid polarizing plate is polarized). The transparent substrate of the plates 37 and 47 is not shown). The wire grid polarizing plate 47 is obtained by inverting the wire grid polarizing plate 37 in the Z direction and further rotating the wire grid polarizing plate 37 by 90 degrees in the XY plane.

In recent years, in mobile devices such as smartphones and tablets, a configuration in which a touch panel function is added to the visible surface side of a display device is becoming common. The touch panel is used as an input means by touching a pointer such as a finger, and the mainstream method is to detect the pointer of the touch panel by changing the capacitance at the touch portion.

The portable display device as described above is required to be thinner and lighter, and the integration of each member is being promoted. For example, an in-cell method having a touch sensing function in a liquid crystal cell has been actively adopted in recent years.

In order to further reduce the thickness and weight, a display device that integrates a color filter substrate and / or a TFT array substrate and a polarizing plate has been proposed (for example, Patent Document 3). In a display device that integrates a polarizing plate in this way, a wire grid polarizing plate is being used because it has high heat resistance and can withstand the film forming process of a liquid crystal display device.

As described above, in the wire grid polarizing plate, a grid pattern of a metal film is formed in a period shorter than the wavelength of light, but the thickness of the grid pattern has sufficient characteristics as a polarizing plate. In addition, it needs to be formed higher than the period of the pattern. Therefore, when it is touched by hand or exposed to external force of air or water, it is very fragile and easily deformed or collapsed.

Further, in the wire grid polarizing plate, the width of the opening (space portion) of the grid pattern is very narrow, which is equal to or less than the wavelength of light. Is known to diffuse and reduce the optical properties of the wire grid polarizing plate.

Therefore, for example, Patent Documents 4 and 5 include a spacer as a sealing enclosing member and a wire grid polarized light having a protective wall corresponding to the spacer in order to prevent deformation and collapse and to protect the wire grid polarizing plate from liquid stains. The structure of the board is disclosed.

By the way, the wire grid polarizing plate is formed by arranging a plurality of wire grid polarizing plates on a large-area glass substrate, and then a scribing process of scratching the glass substrate, a braking process of mechanically breaking the glass substrate triggered by the scratch, and the like. (For example, Patent Document 6). However, cullet (glass residue) is generated in the scribing process and the braking process, and if the cullet is scattered on the surface of the grid pattern, the optical characteristics are deteriorated.

In the conventional wire grid polarizing plate provided with a spacer as in Patent Documents 4 and 5, measures for prevention of deformation / collapse, liquid stains, and foreign substances such as cullet, including the above-mentioned problem at the time of individualization, are taken. The structure of the wire grid polarizing plate considered and the method for manufacturing the same have not been studied.

Japanese Patent No. 4985059 Japanese Unexamined Patent Publication No. 2007-102174 Japanese Unexamined Patent Publication No. 2009-42319 Japanese Patent Publication No. 2005-513547 Japanese Patent No. 5109520 Japanese Patent No. 6163180

The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent deformation and collapse due to an external force, including at the time of individualization, and to prevent liquid stains, cullet, etc. It is an object of the present invention to provide a wire grid polarizing plate which is protected from foreign matter and maintains good optical characteristics, and a method for manufacturing the same.

In order to solve the above problems, the invention according to claim 1 has a transparent substrate that is transparent to a visible light wavelength of at least 380 to 780 nm, and a period smaller than the wavelength on the transparent substrate. A wire grid polarizing plate having a grid-like pattern having metallic protrusions arranged in the above, wherein a spacer having a height equal to or higher than the grid-like pattern is provided in a region surrounding the grid-like pattern in a plan view. A transparent protective material that is transparent to the wavelength and is fixed to the top of the spacer is provided in the region including the lattice pattern in a plan view, and the transparent substrate and the transparent protective material are the same. The spacer forms a sealing structure of the laminate via a spacer, and the spacer is composed of an intermediate resin layer and a curable adhesive layer sandwiching the intermediate resin layer, and each of the above-mentioned curable adhesive layers is an intermediate resin. On the other side not facing the layer, the transparent base material is connected to the transparent protective material, the outermost periphery of the transparent base material, the intermediate resin layer forming the spacer, and each curing. The difference in position from the outermost periphery of the sex adhesive layer and the difference in position between the outermost periphery of the transparent protective material and the outermost periphery of the intermediate resin layer forming the spacer and each curable adhesive layer are both. It is a wire grid polarizing plate characterized by being smaller than 10 μm.

The invention according to claim 2 is characterized in that the width of contact between the transparent substrate and the spacer and the width of contact between the spacer and the transparent protective material are both 100 μm or more. The wire grid polarizing plate according to claim 1.

The invention according to claim 3 is a method for manufacturing a wire grid polarizing plate, which comprises the following steps 1) to 7) .
1) A grid pattern having metal protrusions is surrounded by a non-formed region of the grid pattern in a plan view on a transparent substrate transparent to a visible light wavelength of at least 380 to 780 nm. A process of arranging and forming a plurality of pieces.
2) A step of applying a curable adhesive having a width of 320 μm or more into the non-formed region so as to surround the grid pattern in a plan view.
3) A step of forming an intermediate resin layer substantially the same as the forming width of the curable adhesive on the applied curable adhesive.
4) A step of applying a curable adhesive having substantially the same width as the formation width of the intermediate resin layer on the intermediate resin layer, separately from the curable adhesive.
5) A step of placing a transparent protective material transparent to a visible light wavelength of at least 380 to 780 nm on the curable adhesive applied in 4).
6) Each of the above-mentioned curable adhesives and the intermediate resin layer is cured to form a spacer having a height equal to or higher than the lattice pattern, and the spacer, the transparent base material and the transparent protective material are attached to each other. The process of forming a fixed laminate.
7) The laminate is diced from either the surface side of the transparent protective material or the surface side of the transparent substrate so as to pass the position accuracy ± 20 μm in the width direction from the center of the spacer forming position. A process of individualizing and producing a wire grid polarizing plate.

According to the present invention, a wire grid polarizing plate that is prevented from being deformed or collapsed by an external force even at the time of individualization, is protected from liquid stains, foreign substances such as cullet, and maintains good optical characteristics, and a wire grid polarizing plate thereof. The manufacturing method is obtained. Handling and transportation will be easy, and the progress of the manufacturing process will be smooth.

It is a schematic cross-sectional view of (a) 1st Embodiment, and (b) (a) a partially enlarged view in the broken line frame A which concerns on the wire grid polarizing plate of this invention. It is a schematic sectional drawing of the 2nd Embodiment which concerns on the wire grid polarizing plate of this invention. It is a schematic bird's-eye view for demonstrating the application process of the curable adhesive for spacers among the manufacturing process examples of the wire grid polarizing plate of this invention. FIG. 3 is a schematic bird's-eye view for explaining the formation of a spacer and the fixing of the spacer to the transparent base material and the transparent protective material in the manufacturing process example of the wire grid polarizing plate of the present invention following FIG. Among the examples of the manufacturing process of the wire grid polarizing plate of the present invention, a schematic (left column) for explaining from the arrangement formation of a plurality of lattice patterns to the fixing of the spacer to the transparent substrate and the transparent protective material. It is a plan view and a schematic cross-sectional view (right column). In the manufacturing process example of the wire grid polarizing plate of the present invention following FIG. 5, it is a schematic plan view (left column) and a schematic cross-sectional view (right column) for explaining individualization. It is a schematic cross-sectional view which shows the process example of forming a grid pattern about the wire grid polarizing plate on the visual side of a display device. It is a schematic cross-sectional view which shows the example of the process of forming a grid pattern about the wire grid polarizing plate on the backlight side of a display device. It is a schematic cross-sectional view which shows the example of the liquid crystal display apparatus provided with the conventional wire grid polarizing plate.

Hereinafter, the wire grid polarizing plate and the method for manufacturing the same according to the embodiment of the present invention will be described with reference to the drawings. The same components are designated by the same reference numerals unless there is a reason for convenience. In each drawing, the thickness and ratio of the components may be exaggerated for the sake of readability, and the number of components may be reduced. Further, the present invention is not limited to the following embodiments without departing from the gist thereof.

[Wire grid polarizing plate of the first embodiment]
FIG. 1A is a schematic cross-sectional view of the first embodiment according to the wire grid polarizing plate of the present invention. The wire grid polarizing plate 100 of the first embodiment has a transparent substrate 1 that is transparent to a visible light wavelength of at least 380 to 780 nm, and a metal arranged on the transparent substrate 1 at a period smaller than the wavelength. A wire grid polarizing plate having a grid-like pattern 2 having a sexual convex portion, the spacer 3 having a height of the grid-like pattern 2 or more is provided in a region surrounding the grid-like pattern 2 in a plan view. Further, in the region including the grid pattern 2 in a plan view, a transparent protective material 4 which is fixed to the top of the spacer 3 and is transparent to the wavelength is provided, and the transparent base material 1 and the transparency protection are provided. The material 4 has a sealing structure of a laminated body via a spacer 3.

1 (b) is a partially enlarged view in the broken line frame A of FIG. 1 (a). As shown in FIG. 1 (b), the wire grid polarizing plate 100 has a difference d1 between the outermost peripheral positions of the transparent base material 1 and the spacer 3, and the outermost peripheral positions of the spacer 3 and the transparent protective material 4. The difference d2 is smaller than 10 μm. In the figure, the outer periphery is the spacer 3, the transparent protective material 4, and the transparent base material 1 in this order from the outside, but the present invention is not limited to this. In either order, d1 and d2 are smaller than 10 μm.

The positions of the outermost periphery of the transparent base material 1, the spacer 3, and the transparent protective material 4 do not match, as described later, the wire grid polarizing plate 100 is diced so as to pass through a part of the spacer by a dicing blade. It is manufactured in pieces, but the hardness and elasticity of the transparent base material 1, the spacer 3, and the transparent protective material 4, which are the objects of dicing, are different in addition to the positional accuracy of the dicing process.

As described above, the difference in position between the outermost periphery of the transparent substrate 1 and the outermost periphery of the spacer 3 and the difference in position between the outermost periphery of the transparent protective material 4 and the outermost periphery of the spacer 3 are both 10 μm. Since the spacer 3 is formed to be sufficiently close to the outer periphery of the transparent base material 1 and the transparent protective material 4, the strength of the transparent base material 1 and the transparent protective material 4 against an external force applied to the vicinity of the outer peripheral portion is small. Is secured and deformation / collapse is prevented.

The wire grid polarizing plate 100 of the present invention has a width w1 in which the transparent base material 1 and the spacer 3 are in contact with each other (see FIG. 1B), and a width w2 in which the spacer 3 and the transparent protective material 4 are in contact with each other. However, it is preferable that all of them are 100 μm or more. When the thickness is 100 μm or more, the sealing structure can be maintained even against an external force applied from a horizontal direction to the surface of the wire grid polarizing plate. On the contrary, if w1 and w2 are smaller than 100 μm, there is a risk that the transparent base material 1 or the transparent protective material 4 is peeled off.

As the material of the spacer 3 in the wire grid polarizing plate 100, it is preferable to use a curable adhesive that is cured by ultraviolet rays (UV) or heat. The mechanical strength of the sealed structure is ensured by curing. As the adhesive, an adhesive generally used for semiconductor packages and the like, for example, an epoxy-based adhesive can be adopted.

[Wire grid polarizing plate of the second embodiment]
FIG. 2 is a schematic cross-sectional view of the wire grid polarizing plate 200 according to the second embodiment of the present invention. The structure of the spacer is a single layer structure in the first embodiment of FIG. 1, but in the second embodiment, it has a multi-layer structure in which the intermediate resin layer 13a is sandwiched between the curable adhesives 13b and 13c. By using the curable adhesives 13b and 13c, good adhesion and sealing properties can be obtained with the transparent base material 1 and the transparent protective material 4 also in the second embodiment.

Even if the wire grid polarizing plate 200 of the second embodiment has a multilayer structure, the difference in the position of the outermost periphery between the spacer 13 and the transparent base material 1 and the transparent protective material 4 is the difference in the position of the outermost periphery in the first embodiment of FIG. Similarly, both are smaller than 10 μm. Further, it is preferable that the width of contact between the transparent base material 1 and the curable adhesive 13b and the width of contact between the curable adhesive 13c and the transparent protective material 4 are both 100 μm or more. The width of the intermediate resin layer 13 is substantially equal to the width of the curable adhesives 13b and 13c, and the material of the intermediate resin layer 13 should be a resin having a large elastic modulus so that sufficient strength against external force can be obtained. Is desirable.

[Method for manufacturing the wire grid polarizing plate of the present invention]
Hereinafter, the method for manufacturing the wire grid polarizing plate of the present invention will be described mainly with respect to the wire grid polarizing plate 100 of the first embodiment including the spacer 3 made of the curable adhesive having a single layer structure of FIG.

(From application of curable adhesive to creation of laminate)
FIG. 3 is a schematic bird's-eye view for explaining a step of applying a curable adhesive for spacers in an example of a manufacturing process of a wire grid polarizing plate of the present invention. FIG. 3A shows a grid-like pattern 2 having metal protrusions on a transparent substrate 1 transparent to a visible light wavelength of at least 380 to 780 nm (for simplicity, a plurality thereof is used here. The individualization of the grid pattern is shown in the form of (which will be described later in FIGS. 5 and 6). The process of forming the grid pattern 2 on the transparent substrate 1 will be described later with reference to FIGS. 7 and 8.

FIG. 3B shows a state in which the curable adhesive 3p is being applied to form a spacer in the region surrounding the grid pattern 2. It is preferable that the curable adhesive is applied by patterning only a specific portion by the inkjet method in this way in order to suppress the influence of the grid pattern 2 on the formed region as much as possible. The inkjet method is a maskless, non-contact, non-contact technique that allows droplets to land at the required location and be directly patterned without removing the material (for example, Literature: Journal of the Institute of Electronics, Information and Communication Engineers, Vol. 90). , No. 7, 2007, pp. 544). FIG. 3C shows a form in which the patterning of the curable adhesive 3p is completed. The patterning of the curable adhesive 3p is performed with a film thickness such that the spacer after curing has a height of the grid pattern 2 or more. In the wire grid polarizing plate of the second embodiment of FIG. 2, the curable adhesives 13b and c are similarly applied on the transparent substrate 1 and the intermediate resin layer 13 formed by the photolitho method or the like by the inkjet method. Perform patterning.

FIG. 4 is for explaining the formation of the spacer 3 and the fixing of the spacer 3 to the transparent base material 1 and the transparent protective material 4 in the manufacturing process example of the wire grid polarizing plate of the present invention following FIG. It is a schematic bird's-eye view. In FIG. 4A, a transparent protective material 4 transparent to a visible light wavelength of at least 380 to 780 nm is placed on the applied curable adhesive 3p. As the transparency protective material 4, it is preferable to use a material having a size that at least covers the formation region of the grid pattern 2, and a material having a size equivalent to that of the transparent substrate 1.

After that, the curable adhesive 3p is cured by ultraviolet (UV) irradiation (FIG. 4 (b)) or heating (FIG. 4 (b')) to form a spacer 3 having a height of a grid pattern 2 or more. A laminated body 5 is formed, and the spacer 3 and the transparent base material 1 and the transparent protective material 4 are fixed to each other. By the steps of FIGS. 3 and 4, the transparent base material 1 and the transparent protective material 4 are fixed to the spacer 3 and sealed without touching the grid pattern 2. For UV curing and thermosetting, either one may be used depending on the properties of the adhesive, or both may be used and one may be temporarily cured and the other may be main cured.

(From the formation of multiple grid patterns to the individualization of wire grid polarizing plates)
FIG. 5 is for explaining from the arrangement formation of a plurality of lattice patterns to the fixing of the spacer to the transparent base material and the transparent protective material in the manufacturing process example of the wire grid polarizing plate of the present invention. It is a schematic cross-sectional view of the broken line part of the (left column) schematic plan view and (right column) plan view. The steps of FIGS. 5A to 5C are basically the same as the steps of FIGS. 3 to 4, except that a plurality of grid patterns 2 are formed.

FIG. 5A shows a lattice-like pattern 2 having metal protrusions on a transparent substrate 1 transparent to a visible light wavelength of at least 380 to 780 nm, and non-formation of the lattice-like pattern in a plan view. A morphology formed by arranging a plurality of (4 × 4 in the figure) so as to be surrounded by the region 2s is shown.

In FIG. 5 (b), the curable adhesive 3p is formed in the non-formed region 2s of the grid pattern so as to surround the grid pattern 2 in a plan view by the same method as in FIGS. 3 (b) and 3 (c). In FIG. 5 (c), a transparent protective material 4 transparent to a visible light wavelength of at least 380 to 780 nm is placed on the applied curable adhesive 3p, and then the curable adhesive 3p is placed. Is cured to form a spacer 3 having a height of a lattice pattern 2 or more, and the form of a laminated body 5 m in which the spacer 3, a transparent base material, and a transparent protective material are fixed and sealed is shown. .. Since this step is performed on the large-area transparent substrate 1, a plurality of sealed structures are formed on the large-area substrate in a plan view.

FIG. 6 is a schematic cross-sectional view of a broken line portion of a (left column) schematic plan view and a (right column) plan view for explaining individualization in the manufacturing process example of the wire grid polarizing plate of the present invention following FIG. It is a figure. The laminated body 5 m prepared as described above is diced by a blade 7 so as to pass through a part of the spacer 3 from the surface side of the transparent protective material 4 along the dicing line DL, and is separated into individual pieces. Wire grid polarizing plates 101 and 102 having the same shape as that of the first embodiment are manufactured. Although the blade 7 is inserted from the surface side of the transparent protective material 4 in the figure, it may be inserted from the surface side of the transparent base material 1.

More specifically, one surface of the transparent protective material 4 or the transparent base material 1 is fixed to the dicer, and dicing is performed with the blade 7 so as to pass through the central portion of the spacer 3 from the other surface. It is desirable that the dicing position accuracy can be processed with an accuracy of at least ± 40 μm, and it is further desirable that the dicing can be processed with an accuracy of ± 20 μm. For example, assuming that the width of the spacer 3 removed in the dicing step is 100 μm, when the dicing position accuracy is ± 20 μm, the width of the spacer 3 when the laminate 5 m is created in FIG. 5 (c) is 320 μm or more. Therefore, the width W (μm) of the spacer of each wire grid polarizing plate after individualization is
(320-100-20) / 2≤W≤ (320-100 + 20) / 2
That is, 100 ≦ W ≦ 120, and W can be set to 100 μm or more. As a result, excellent adhesive strength can be obtained, and the sealing structure can be maintained even against an external force applied from a horizontal direction. Since the grid pattern 2 is protected by the sealing structure, the cooling water and the refrigerant generally used for blade dicing can be used without any problem.

[Formation of grid pattern of wire grid polarizing plate]
Hereinafter, a step of forming a grid pattern on the transparent substrate will be described.
FIG. 7 is a schematic cross-sectional view showing an example of a process of forming a grid pattern in the wire grid polarizing plate on the visual side of the display device. Here, a case where the grid pattern side is the visual recognition side as in the wire grid polarizing plate 37 of FIG. 9 will be described.

In FIGS. 1 to 6, for the sake of simplicity, the grid pattern is a single-layer pattern of a metal film, but in practice, the grid pattern is preferably a multilayer film pattern as shown in FIG. 7. The resin layer pattern that is the original pattern of the lattice pattern 22 (see FIG. 7 (4)) can be formed by an electron beam lithography method, a two-luminous flux interferometry, or the like, but from the viewpoint of productivity, the imprint method is used. (See, for example, "Optical Technology Contact", November 2010 issue, Japan Optomechatronics Association,). Hereinafter, the case where the imprint method is used will be described.

(Multilayer film formation: Fig. 7 (1))
When Al is used as the metal film 22-a, it is preferable to laminate Al after forming the adhesion auxiliary layer 22-b such as a molybdenum / niobium alloy in consideration of the adhesion to the transparent substrate. The film thickness of the Al layer is preferably about 200 nm, and the film thickness of the molybdenum / niobium layer as the adhesion auxiliary layer is preferably about 20 nm. When Ag is used, it is desirable to use APC (aluminum / palladium / copper alloy) manufactured by Furuya Metal Co., Ltd. in consideration of reliability such as heat resistance.

The visual side of the grid pattern 22 is required to suppress the reflectance to external light as much as possible. Therefore, low reflection processing is required on the surface of the metal film. Typical examples of low-reflection processing include oxidative blackening treatment by erosion into a plating solution and lamination of a blackening layer. The blackening layer is composed of a colored resin in which a black coloring material is dispersed, and as the black coloring material, carbon, carbon nanotubes, or a mixture of a plurality of organic pigments can be applied. Alternatively, there is also a method of laminating an inorganic thin film and using light interference or light absorption to reduce the reflection. The case of using the blackened layer will be described below.

When the grid pattern 22 side is the visual recognition side as shown in FIG. 7, it is preferable to laminate the blackening layer 22-c on the metal film 22-a as shown in FIG. 7 (1). The film thickness of the blackened layer 22-c is preferably about 20 nm. A film such as SiO ₂ may be further laminated on the blackened layer 22-c for a hard mask during dry etching. On the contrary, when the transparent base material 21 side is the visual recognition side, the stacking order of the metal film 22-a and the blackening layer 22-c is reversed.

(Resin layer coating: Fig. 7 (2))
Apply a resin layer for imprint shaping. A spin coding method or the like can be adopted for coating the resin layer. As the resin, for example, a general-purpose imprint resin PAC-01 (trade name) manufactured by Toyo Synthetic Co., Ltd. can be used, and the film thickness is preferably about 120 nm after solvent drying.

(Patterning of resin layer by imprint: Fig. 7 (3))
By the imprint method, for example, a grid-like resin layer pattern having a period of 100 nm and a line width of 50 nm is formed. Cross-linking of the resin after imprinting may be performed by heat or UV, but in order to avoid thermal influence, a UV imprint method using an imprint mold transparent to the UV cross-linking type resin is preferable.

(Etching of multilayer film and peeling of resin layer: Fig. 7 (4))
The patterning of the blackened layer 22-c can be performed by wet etching or dry etching using the resin layer pattern as a mask. It is preferable that the metal film 22-b is etched by dry etching in consideration of the thickness of the blackened layer and the fine processability. Since dry etching is excellent in directivity, it is possible to form a metal film pattern 22-a'that is vertical and has good linearity. The optimum gas for the etching gas differs depending on the metal film, but it is appropriately selected from fluorine-based gas, chlorine-based gas, oxygen-based gas, and the like. Etching of the adhesion auxiliary layer 22-b can also be performed by wet etching or dry etching. The resin layer pattern, which is an etching mask, can be peeled off in synchronization with the end of dry etching by adjusting the etching rate. If it remains after the dry etching is completed, it is peeled off by an alkaline solution, an organic solvent, oxygen plasma, or the like.

FIG. 8 is a schematic cross-sectional view showing an example of a step of forming a grid pattern 22'(see FIG. 8 (4)) in the wire grid polarizing plate on the backlight side of the display device. Here, the case where the grid pattern 22'side is the backlight side is shown. For example, the wire grid polarizing plate 47 in FIG. 9 is obtained by turning the wire grid polarizing plate 37 upside down and further rotating it by 90 degrees in the XY plane, so that the grid pattern 22'side is the backlight side.

Since the wire grid polarizing plate formed on the backlight side is required to have an effect of improving the light extraction efficiency by retroreflection, it is desirable that the surface of the metal film has a high reflectance of TE polarization. The retroreflection is a phenomenon in which the incident light is reflected toward the light source again. Therefore, the structure of the multilayer film is as shown in FIG. 8 (1), the blackening layer for low reflection is unnecessary, and only the metal film 22-a and the adhesion auxiliary layer 22-b are required. On the contrary, in the case of the display device in which the transparent base material 21 side is the backlight side, the layer structure of the multilayer film is the same as that in FIG. 8 (1).

As described above, the wire grid polarizing plate installed on the backlight side does not require a blackening layer, and therefore, the process of forming the grid pattern 22'in FIG. 8 requires the formation and etching of the blackening layer. The only difference from FIG. 7 is that it does not, and the other points are the same as those in FIG. 7, so the description thereof will be omitted.

By the method as described above, a plurality of lattice patterns are arranged in an array, a sealed structure of a laminate composed of a transparent substrate, a spacer and a transparent protective material is produced, and the wire grid polarizing plate is individualized. The wire grid polarizing plate of the present invention is manufactured. The wire grid polarizing plate of the present invention has the following advantages.
1) Since it has a transparent protective material, it is unlikely that the grid pattern will be deformed or collapsed by touching it with hands or applying pressure with air or water.
2) By covering the upper part of the grid pattern with a transparent protective material and adopting a sealing structure via a spacer, liquid stains can enter the fine concave portions of the grid pattern and become individualized on the convex parts. It is possible to prevent foreign matter such as cullet from adhering.
3) Since the spacer is formed close enough to the outer periphery of the transparent base material and the transparent protective material, the strength of the transparent base material and the transparent protective material against external force applied to the vicinity of the outer periphery is ensured, including at the time of individualization. It is prevented from being deformed and collapsed.
4) The advantages of 1) to 3) make handling and transportation easier, and the entire process can be carried out in a clean room, and the risk of dirt and foreign matter adhering during subsequent processes and use is eliminated, which is good. A wire grid polarizing plate that maintains optical characteristics can be obtained.

100 ... Wire grid polarizing plate (first embodiment of the present invention)
101, 102 ... Wire grid polarizing plate after individualization (first embodiment of the present invention)
200 ... Wire grid polarizing plate (second embodiment of the present invention)
1 ... Transparent substrate 2 ... Lattice pattern 2s ..... Non-formed regions of the grid pattern 3, 13 ... Spacer 3p ...・ ・ ・ Curing adhesive (before curing)
13a ... Intermediate resin layers 13b, 13c ... Curable adhesive 4 ... Transparent protective material 5, 5m ... Laminated body 6 ... Inkjet head 7 ... Blade DL ... Dicing line 21 ... Transparent substrate 22, 22'... Grid pattern 22-a ...・ Metal film, 22-a'・ ・ ・ ・ Metal film pattern 22-b ・ ・ ・ ・ Adhesion auxiliary layer, 22-b' ・ ・ ・ ・ Adhesion auxiliary layer pattern 22-c ・ ・ ・ ・ Blackening layer, 22 -C'... Blackened layer pattern 300 ... Liquid crystal display device 30 ... Color filter substrate 31 ... Transparent substrate 32 ... Black matrix 33 (R) ・ ・ ・ Color filter layer (red)
33 (G) ・ ・ ・ Color filter layer (green)
33 (B) ... Color filter layer (blue)
34 ... Flattening layer 35, 45 ... Alignment film 36, 46 ... Adhesive layer 37, 47 ... Wire grid polarizing plate 40 ... TFT array substrate 41 ...・ ・ ・ Second transparent substrate 42 ・ ・ ・ ・ ・ ・ TFT array part 50 ・ ・ ・ ・ ・ ・ Liquid crystal layer

Claims (3)

A wire grid having a transparent substrate transparent to a visible light wavelength of at least 380 to 780 nm and a lattice pattern having metallic protrusions arranged on the transparent substrate at a period smaller than the wavelength. It ’s a polarizing plate,
A spacer having a height higher than that of the grid pattern is provided in the area surrounding the grid pattern in a plan view.
A transparent protective material that is transparent to the wavelength and is fixed to the top of the spacer is provided in the region including the grid pattern in a plan view.
The transparent base material and the transparent protective material form a sealing structure of a laminated body via the spacer.
The spacer is composed of an intermediate resin layer and a curable adhesive layer sandwiching the intermediate resin layer, and each of the above-mentioned curable adhesive layers is the other surface that does not face the intermediate resin layer and is transparent. It is connected to the sex substrate and the transparent protective material, and is connected to the transparent protective material.
The difference in position between the outermost periphery of the transparent substrate and the outermost periphery of the intermediate resin layer forming the spacer and the outermost periphery of each curable adhesive layer , and the outermost periphery of the transparent protective material and the intermediate resin forming the spacer. A wire grid polarizing plate characterized in that the difference in position between the layer and the outermost periphery of each curable adhesive layer is smaller than 10 μm. The wire according to claim 1, wherein the width of contact between the transparent substrate and the spacer and the width of contact between the spacer and the transparent protective material are both 100 μm or more. Grid polarizing plate. A method for manufacturing a wire grid polarizing plate, which comprises the following steps 1) to 7) .
1) A grid pattern having metal protrusions is surrounded by a non-formed region of the grid pattern in a plan view on a transparent substrate transparent to a visible light wavelength of at least 380 to 780 nm. A process of arranging and forming a plurality of pieces.
2) A step of applying a curable adhesive having a width of 320 μm or more into the non-formed region so as to surround the grid pattern in a plan view.
3) A step of forming an intermediate resin layer substantially the same as the forming width of the curable adhesive on the applied curable adhesive.
4) A step of applying a curable adhesive having substantially the same width as the formation width of the intermediate resin layer on the intermediate resin layer, separately from the curable adhesive.
5) A step of placing a transparent protective material transparent to a visible light wavelength of at least 380 to 780 nm on the curable adhesive applied in 4).
6) Each of the above-mentioned curable adhesives and the intermediate resin layer is cured to form a spacer having a height equal to or higher than the lattice pattern, and the spacer, the transparent base material and the transparent protective material are attached to each other. The process of forming a fixed laminate.
7) The laminate is diced from either the surface side of the transparent protective material or the surface side of the transparent substrate so as to pass the position accuracy ± 20 μm in the width direction from the center of the spacer forming position. A process of individualizing and producing a wire grid polarizing plate.

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