JP7632170B2 - Manufacturing method of liquid crystal device - Google Patents

Description

The present invention relates to a method for manufacturing a liquid crystal device, and can be applied to the process of creating a liquid crystal device by bonding a light control cell (liquid crystal cell) that controls the amount of transmitted light to a glass plate.

A conventional configuration has been proposed in which a light-adjusting cell (liquid crystal cell) that uses liquid crystal to control the amount of light transmitted is created, and this light-adjusting cell (liquid crystal cell) is placed between two transparent substrates and a liquid crystal device is created using laminated glass (see, for example, Patent Documents 1 and 2).

International Publication No. 2019/198748 JP 2021-64005 A

However, when creating a liquid crystal device by placing a liquid crystal cell between two transparent substrates made of glass or the like, as the size of the transparent substrate increases, the weight of the transparent substrate also increases, which can cause the transparent substrate to fall and break during the manufacturing process.

The objective of the embodiment of the present disclosure is to provide a method for manufacturing a liquid crystal device that can reduce damage to the transparent substrates when a liquid crystal device is created by placing a liquid crystal cell between two transparent substrates.

The embodiments of the present disclosure solve the above problems by the following solutions. Note that, for ease of understanding, the embodiments of the present disclosure are described with reference symbols corresponding to the embodiments, but are not limited to these.

(1) The first disclosed embodiment is a method for manufacturing a liquid crystal device (1) including a first transparent substrate (41), a second transparent substrate (42) having an outer shape smaller than that of the first transparent substrate, and a liquid crystal cell arranged between the first transparent substrate and the second transparent substrate, the method comprising: a placement step of placing the first transparent substrate on a buffer member (50) arranged outside the second transparent substrate so as to face the liquid crystal cell stacked on the second transparent substrate at a distance; and a integration step of contracting the buffer member to bring the first transparent substrate closer to the liquid crystal cell, and integrating the first transparent substrate, the liquid crystal cell, and the second transparent substrate.

(2) The second disclosed embodiment is a manufacturing method for a liquid crystal device (1) in which the integration step is performed by exhausting the atmosphere on the second transparent substrate (42) side of a diaphragm sheet (63) arranged to face the first transparent substrate (41), thereby pressing the diaphragm sheet with atmospheric pressure to contract the buffer member (50).

(3) A method for manufacturing a liquid crystal device (1) according to (1) or (2), comprising a coating step of coating a bonding material (31A) on the upper surface of the liquid crystal cell (10) laminated on the second transparent substrate (42), and a gap is formed between the first transparent substrate (41) placed on the buffer member (50) in the placement step and the bonding material on the liquid crystal cell.

According to an embodiment of the present disclosure, when a liquid crystal device is created by placing a liquid crystal cell between glass plates, damage to the glass plates can be sufficiently reduced.

1 is a diagram illustrating a liquid crystal device according to an embodiment. 1 is a cross-sectional view of a liquid crystal device according to an embodiment. 3A to 3C are diagrams illustrating a manufacturing process of the liquid crystal device according to the embodiment. FIG. 4 is a diagram illustrating the continuation of FIG. 3 . FIG. 5 is a diagram illustrating the continuation of FIG. 4 . 5A to 5C are diagrams illustrating a bonding process of the liquid crystal device according to the embodiment. FIG. 7 is a diagram illustrating the continuation of FIG. 6 .

[Embodiment]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view showing a configuration of a liquid crystal device 1 according to an embodiment of the present disclosure.
Note that the figures shown below, including FIG. 1, are schematic views, and the size and shape of each part are appropriately exaggerated for ease of understanding.
In the following description, specific numerical values, shapes, materials, etc. are given, but these can be changed as appropriate.
In this specification, terms specifying shapes or geometric conditions, such as parallel and orthogonal, are intended to include not only their strict meanings but also states that have a similar optical function and have an error that can be regarded as parallel or orthogonal.

In this specification, the terms plate, sheet, film, etc. are used, and in general usage, they are used in the order of thickness, plate, sheet, film, etc., and this specification follows that order. However, since such distinction in usage has no technical meaning, these terms can be used interchangeably as appropriate.
In this specification, the sheet surface refers to the surface of each sheet that is in the planar direction of the sheet when viewed as a whole. The same applies to plate surfaces and film surfaces. In addition, a plan view refers to a state viewed from the normal direction of the sheet surface (plate surface, film surface).

In the present specification and claims, the term "transparent" refers to a material that transmits at least the light of the wavelength to be used. For example, even if a material does not transmit visible light, if it transmits infrared light, it will be treated as transparent when used for infrared applications.
It should be noted that the specific numerical values specified in this specification and claims should be treated as including a general error range. In other words, a difference of about ±10% means that there is no substantial difference, and values set within a range slightly exceeding the numerical range of this invention should be interpreted as being substantially within the scope of this invention.

The liquid crystal device 1 according to the embodiment of the present disclosure can be applied to various technical fields requiring adjustment of light transmittance, and the scope of application is not particularly limited. The liquid crystal device 1 is disposed in a portion where light control is required, such as the window glass of a building, a showcase, an indoor transparent partition, a vehicle window (e.g., a front, side, rear, roof window, etc.), a partition board inside a vehicle, etc. This makes it possible to control the amount of light incident on the inside of a building, vehicle, etc., or to control the amount of light incident on a specified area inside a building, vehicle, etc.

The liquid crystal device 1 according to the embodiment of the present disclosure may be configured with a three-dimensional shape having a curved surface shape, for example, the liquid crystal device 1 may have a shape that is convex on one side. Note that the liquid crystal device 1 is not limited to this, and may have a planar surface shape (i.e., a flat plate shape), for example. In the following figures including FIG. 1, the surface shape is shown as planar for simplicity.

As shown in FIG. 1, the liquid crystal device 1 according to the embodiment of the present disclosure includes a first glass plate (first transparent substrate) 41, a first bonding layer 31, a liquid crystal cell 10, a second bonding layer 32, and a second glass plate (second transparent substrate) 42, which are stacked in the thickness direction in the above-mentioned order.

FIG. 2 is a cross-sectional view showing the layer structure of the liquid crystal device 1 (laminated glass) according to an embodiment of the present disclosure.
2 , the liquid crystal device 1 includes a first glass plate 41, a second glass plate 42, and a liquid crystal cell 10 disposed between the first glass plate 41 and the second glass plate 42. The liquid crystal cell 10 includes a first substrate 12, a second substrate 13, and a liquid crystal layer 14 disposed between the first substrate 12 and the second substrate 13.

The first glass plate (first transparent substrate) 41 and the second glass plate (second transparent substrate) 42 are disposed on the front and back surfaces of the liquid crystal device 1, respectively, and are plate glasses having high light transmittance.
In the embodiment of the present disclosure, the first glass plate 41 and the second glass plate 42 have a thickness of 0.5 mm or more and 4 mm or less, and as an example, a plate glass having a thickness of 2 mm is used for both. When inorganic glass is used as the first glass plate 41 and the second glass plate 42, the liquid crystal device 1 can have excellent heat resistance and scratch resistance. The first glass plate 41 and the second glass plate 42 may be subjected to a surface treatment such as a hard coat, if necessary.
Instead of inorganic glass, a transparent resin plate, so-called resin glass, may be used for the first glass plate (first transparent substrate) 41 and the second glass plate (second transparent substrate) 42. For example, polycarbonate, acrylic, etc. may be used as the resin glass used for the first transparent substrate and the second transparent substrate. When resin glass is used for the first transparent substrate and the second transparent substrate, the liquid crystal device 1 can be made lighter.

The first bonding layer 31 is disposed between the first glass plate 41 and the liquid crystal cell 10, and is a member that bonds the first glass plate 41 and the liquid crystal cell 10 to each other. The first bonding layer 31 is larger in size than the liquid crystal cell 10 in a plan view.
2, in a cross-sectional view, the first bonding layer 31 is formed not only in the region overlapping the liquid crystal cell 10 but also in a portion corresponding to the periphery of the liquid crystal cell 10, and is connected to the second bonding layer 32 in this portion. Furthermore, in the liquid crystal device 1, a stopper 35 is provided around the first bonding layer 31, and this stopper 35 prevents leakage of the bonding material (OCR material 31A) from the first bonding layer 31 before hardening during the manufacturing process of the liquid crystal device 1. Furthermore, by forming the first bonding layer 31 in this form, it is possible to prevent the side surface or a part thereof of the liquid crystal cell 10 from being exposed to the side surface of the liquid crystal device 1, and also to suppress the intrusion of moisture and the like from the side surface of the liquid crystal device 1, thereby further improving the water-proofing property of the liquid crystal device 1.

In the embodiment of the present disclosure, the first bonding layer 31 is composed of OCR (Optical Clear Resin). The OCR is a cured product obtained by curing a liquid curable adhesive layer composition containing a polymerizable compound. Specifically, the OCR is obtained by applying a liquid resin, which is a mixture of a base resin such as an acrylic resin, a silicone resin, or a urethane resin, and an additive, to an object, and then curing the liquid resin using ultraviolet (UV) rays or the like.
The first bonding layer 31 has optical transparency, and preferably has heat resistance up to at least about 120° C., moist heat resistance, and weather resistance.
The thickness of the first bonding layer 31 may be appropriately selected depending on the material thereof, etc. Specifically, the thickness of the first bonding layer 31 in the region overlapping with the liquid crystal cell 10 in a plan view may be 30 μm or more and 1000 μm or less.
The stopper 35 is made of the same material as the first bonding layer 31, and is formed on the outer edge of the surface of the second bonding layer 32 on the side where the liquid crystal cell 10 is disposed.

The second bonding layer 32 is disposed between the second glass plate 42 and the liquid crystal cell 10, and is a member that bonds the second glass plate 42 and the liquid crystal cell 10 to each other. The second bonding layer 32 is larger in size than the liquid crystal cell 10 in a plan view.
In the embodiment of the present disclosure, the second bonding layer 32 is made of an optical clear adhesive (OCA). The OCA is a layer produced, for example, as follows.
First, a liquid composition for a curable adhesive layer containing a polymerizable compound is applied onto a release film such as polyethylene terephthalate (PET), and then cured using, for example, ultraviolet (UV) rays to obtain an OCA sheet. The composition for a curable adhesive layer may be an optical pressure-sensitive adhesive such as an acrylic resin, a silicone resin, or a urethane resin.
After this OCA sheet is attached to an object, the release film is peeled off and removed to obtain a layer made of the OCA.

The second bonding layer 32 made of OCA has optical transparency, and further preferably has heat resistance up to at least about 120° C., moist heat resistance, and weather resistance.
In the embodiment of the present disclosure, the second bonding layer 32 is described as being made of OCA by way of example, but is not limited thereto, and may be made of OCR like the first bonding layer 31 .
The thickness of the second bonding layer 32 may be appropriately selected depending on the material, etc. Specifically, the thickness of the second bonding layer 32 may be 30 μm or more and 500 μm or less, and is preferably 50 μm or more and 200 μm or less.

In the embodiment of the present disclosure, the first bonding layer 31 directly bonds the first glass plate 41 and the liquid crystal cell 10. Moreover, the second bonding layer 32 directly bonds the second glass plate 42 and the liquid crystal cell 10. Without being limited thereto, for example, a film such as an ultraviolet (UV) cut film may be interposed at least at one location between the first glass plate 41 and the liquid crystal cell 10 and between the second glass plate 42 and the liquid crystal cell 10.
As described above, in the embodiment of the present disclosure, the first bonding layer 31 and the second bonding layer 32 are bonded bodies containing a non-pressure adhesive component. Here, the term "bonded body containing a non-pressure adhesive component" refers to a bonded body that does not require pressure to be properly bonded to an adjacent object and that can be moderately bonded to an adjacent object under normal pressure.

The liquid crystal cell 10 (light control film, liquid crystal film) is a film that can control the amount of transmitted light by changing the applied voltage. The liquid crystal cell 10 is disposed so as to be sandwiched between a first glass plate 41 and a second glass plate 42.
The liquid crystal cell 10 has a guest-host type liquid crystal layer using a dichroic dye, and is a member that changes the amount of transmitted light depending on an electric field applied to the liquid crystal. The liquid crystal cell 10 includes a first substrate 12 in the form of a film, a second substrate 13 in the form of a film, and a liquid crystal layer 14 disposed between the first substrate 12 and the second substrate 13.

The first substrate 12 and the second substrate 13 each include a first transparent electrode 22A, a second transparent electrode 22B, a first alignment layer 23A, and a second alignment layer 23B. More specifically, the first transparent electrode 22A and the first alignment layer 23A are formed in this order on the surface of the first substrate 12 facing the liquid crystal layer 14, and the second transparent electrode 22B and the second alignment layer 23B are formed in this order on the surface of the second substrate 13 facing the liquid crystal layer 14.
Furthermore, a plurality of bead spacers 24 are disposed between the first substrate 12 and the second substrate 13. The liquid crystal layer 14 is filled and disposed between the plurality of bead spacers 24 between the first substrate 12 and the second substrate 13. The plurality of bead spacers 24 may be disposed irregularly or regularly.

The liquid crystal cell 10 changes the orientation of the liquid crystal material made of a guest-host liquid crystal composition provided in the liquid crystal layer 14 by driving the first transparent electrode 22A and the second transparent electrode 22B provided on the first substrate 12 and the second substrate 13, thereby changing the amount of transmitted light.

The first substrate 12 and the second substrate 13 are preferably made of a transparent resin and are flexible films. The first substrate 12 and the second substrate 13 are preferably made of a transparent resin film having small optical anisotropy and a transmittance of 80% or more in the visible wavelength range (380 nm or more and 800 nm or less).
Examples of materials for such transparent resin films include acetylcellulose-based resins such as triacetylcellulose (TAC), polyester-based resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyolefin-based resins such as polyethylene (PE), polypropylene (PP), polystyrene, polymethylpentene, and EVA, vinyl-based resins such as polyvinyl chloride and polyvinylidene chloride, acrylic resins, polyurethane-based resins, polysulfone (PSF), polyethersulfone (PES), polycarbonate (PC), polyether (PE), polyether ketone (PEK), (meth)acrylonitrile, cycloolefin polymer (COP), and cycloolefin copolymer resins. Resins such as polycarbonate, cycloolefin polymer, and polyethylene terephthalate are particularly preferred as materials for transparent resin films.

The thickness of the transparent resin film used as the first substrate 12 and the second substrate 13 may vary depending on the material, but may be appropriately selected within a range in which the transparent resin film has flexibility. The thickness of the first substrate 12 and the second substrate 13 may be 50 μm or more and 200 μm or less.
In the embodiment of the present disclosure, as an example of the first substrate 12 and the second substrate 13, a polyethylene terephthalate film having a thickness of 125 μm is applied.

The first transparent electrode 22A and the second transparent electrode 22B are composed of transparent conductive films laminated on the first substrate 12 and the second substrate 13, respectively. As the transparent conductive film, various transparent electrode materials that are applied to this type of transparent resin film can be applied, and examples of such transparent conductive films include oxide-based transparent metal thin films with a total light transmittance of 50% or more, such as tin oxide-based, indium oxide-based, and zinc oxide-based.

Examples of tin oxide (SnO2) include NESA (tin oxide SnO2), ATO (antimony tin oxide), and fluorine-doped tin oxide. Examples of indium oxide (In2O3) include indium oxide, ITO (indium tin oxide), and IZO (indium zinc oxide). Examples of zinc oxide (ZnO) include zinc oxide, AZO (aluminum doped zinc oxide), and gallium doped zinc oxide.
In the embodiment of the present disclosure, the transparent conductive film constituting the transparent electrode is formed of ITO.

The bead spacer 24 is a member that defines the thickness (cell gap) of the liquid crystal layer 14 except for the outer periphery. In the embodiment of the present disclosure, a spherical bead spacer is used as the bead spacer 24. The diameter of the bead spacer 24 may be 1 μm or more and 20 μm or less, and is preferably 3 μm or more and 15 μm or less.
The bead spacer 24 can be made of a wide variety of materials, including inorganic materials such as silica, organic materials, and core-shell structures that combine these materials.
In addition to the spherical shape, the bead spacer may be configured in a rod shape such as a cylindrical shape, an elliptical cylindrical shape, a polygonal prism shape, etc. Although the bead spacer 24 is manufactured from a transparent material, a colored material may be applied as necessary to adjust the color.

In the embodiment of the present disclosure, the bead spacer 24 is provided on the second substrate 13, but this is not limited thereto, and the bead spacer 24 may be provided on both the first substrate 12 and the second substrate 13, or only on the first substrate 12. Also, the bead spacer 24 does not necessarily have to be provided. Also, instead of the bead spacer 24, or together with the bead spacer 24, a columnar spacer may be used.

The first alignment layer 23A and the second alignment layer 23B are members for aligning the liquid crystal molecules contained in the liquid crystal layer 14 in a desired direction.
The first alignment layer 23A and the second alignment layer 23B are formed of a photo-alignment layer. As a photo-alignment material applicable to the photo-alignment layer, various materials to which a photo-alignment method can be applied can be widely used, and examples thereof include a photodecomposition type, a photodimerization type, a photoisomerization type, and the like.
In the embodiment of the present disclosure, a photodimerization type material is used. Examples of the photodimerization type material include polymers having cinnamate, coumarin, benzylidenephthalimidine, benzylideneacetophenone, diphenylacetylene, stilbazole, uracil, quinolinone, maleimide, or cinnamylideneacetic acid derivatives. As the photodimerization type material, a polymer having one or both of cinnamate and coumarin is preferably used, in particular because of its good alignment control force.

In addition, a rubbing alignment layer may be used instead of the photo-alignment layer. The rubbing alignment layer may not be subjected to a rubbing treatment, or may be subjected to a rubbing treatment and then subjected to a shaping treatment to form fine line-shaped irregularities to prepare the alignment layer.
In the embodiment of the present disclosure, the liquid crystal cell 10 includes an alignment layer on each of the first substrate 12 and the second substrate 13, but is not limited thereto, and may have a configuration that does not include an alignment layer.

A wide variety of guest-host liquid crystal compositions and dichroic dye compositions can be used for the liquid crystal layer 14. The guest-host liquid crystal composition may contain a chiral agent so that the liquid crystal material is aligned in a helical shape in the thickness direction of the liquid crystal layer 14 when the liquid crystal material is aligned horizontally.
In addition, a sealant 25 having a ring or frame shape in a plan view is disposed between the first substrate 12 and the second substrate 13 so as to surround the liquid crystal layer 14. The sealant 25 holds the first substrate 12 and the second substrate 13 together and prevents leakage of the liquid crystal material. The sealant 25 may be a thermosetting resin such as an epoxy resin or an acrylic resin, or an ultraviolet-curable resin.

For the liquid crystal layer 14, a nematic liquid crystal compound, a smectic liquid crystal compound, or a cholesteric liquid crystal compound can be used as a liquid crystal compound having no polymerizable functional group.
Examples of nematic liquid crystal compounds include biphenyl-based compounds, terphenyl-based compounds, phenylcyclohexyl-based compounds, biphenylcyclohexyl-based compounds, phenylbicyclohexyl-based compounds, trifluoro-based compounds, phenyl benzoate-based compounds, phenyl cyclohexylbenzoate-based compounds, phenyl benzoate-based compounds, phenyl bicyclohexylcarboxylate-based compounds, azomethine-based compounds, azo-based compounds, azooxy-based compounds, stilbene-based compounds, tolane-based compounds, ester-based compounds, bicyclohexyl-based compounds, phenylpyrimidine-based compounds, biphenylpyrimidine-based compounds, pyrimidine-based compounds, and biphenylethyne-based compounds.

Examples of the smectic liquid crystal compound include ferroelectric polymer liquid crystal compounds such as polyacrylates, polymethacrylates, polychloroacrylates, polyoxiranes, polysiloxanes, and polyesters.
Examples of the cholesteric liquid crystal compound include cholesteryl linoleate, cholesteryl oleate, cellulose, cellulose derivatives, and polypeptides.

Dichroic dyes used in the guest-host system are dyes that are soluble in liquid crystals and have high dichroic properties, such as azo, anthraquinone, quinophthalone, perylene, indigo, thioindigo, merocyanine, styryl, azomethine, and tetrazine dichroic dyes.

The liquid crystal cell 10 is configured as a normally dark cell by configuring the first alignment layer 23A and the second alignment layer 23B as horizontal alignment layers in which an alignment restraining force related to a pretilt is set in a certain direction so that the alignment of the guest-host liquid crystal composition during light shielding is formed during the absence of an electric field. Note that the liquid crystal cell 10 may be configured as a normally clear cell by configuring the liquid crystal cell 10 during light shielding as a normally clear cell during the application of an electric field.
Normally dark is a structure in which the transmittance is at a minimum when no voltage is applied to the liquid crystal, resulting in a black screen, whereas normally clear is a structure in which the transmittance is at a maximum when no voltage is applied to the liquid crystal, resulting in a transparent screen.

In addition, since it is desirable that the scenery and the like seen through the liquid crystal cell 10 be clearly visible when light is transmitted, it is desirable that the haze value when light is transmitted is low. Specifically, the haze value of the liquid crystal cell 10 when light is transmitted is desirably 30% or less, and more desirably 15% or less. In order to achieve such a low haze value, it is desirable that the liquid crystal mixture does not contain a polymerizable compound.

The liquid crystal cell 10 of the embodiment of the present disclosure is shown as an example having a guest-host type liquid crystal layer 14, but is not limited to this. The liquid crystal cell 10 may be configured to have a liquid crystal layer 14 of a TN (Twisted Nematic) type, a VA (Vertical Alignment) type, an IPS (In-Plane-Switching) type, or the like that does not use a dichroic dye composition. When such a liquid crystal layer 14 is provided, it can function as a light control film by further providing a linear polarization layer on each of the surfaces of the first substrate 12 and the second substrate 13.

As shown in FIG. 1, a flexible printed circuit board 18 is disposed on the liquid crystal cell 10 to electrically connect the transparent electrodes to the outside.

(Manufacturing process)
Next, a method for manufacturing the liquid crystal device 1 according to the embodiment of the present disclosure will be described with reference to FIGS.
3 to 5 are diagrams illustrating a method for manufacturing the liquid crystal device 1 according to the embodiment of the present disclosure. In FIG. 3 to FIG. 5, the manufacturing method is explained with reference to cross-sectional views of the liquid crystal device 1.

First, prepare the second glass plate 42 as shown in FIG. 3(a).

3B, a second bonding layer 32 made of OCA is bonded onto the second glass plate 42. In this case, for example, an OCA sheet having the second bonding layer 32 and a release film 36 is bonded to the second glass plate 42, and then the release film 36 is peeled off and removed, thereby bonding the second bonding layer 32 onto the second glass plate 42. The second bonding layer 32 may be bonded to the entire area of one side of the second glass plate 42, or may be bonded to a partial area.
In the above description, an example in which an OCA sheet is used as the second bonding layer 32 is shown, but the present invention is not limited thereto. For example, the second bonding layer 32 may be formed by applying an OCR material onto the second glass plate 42 and temporarily curing the applied OCR material. Here, the temporarily cured state refers to a state in which the adhesiveness of the OCR material is maintained to a certain degree without completely curing the OCR material. The amount of ultraviolet (UV) radiation applied at this time is less than the amount of radiation applied when completely curing the OCR material 31A (first bonding layer 31), and may be, for example, 50% to 80%.

3C, the liquid crystal cell 10, which has been separately prepared, is bonded onto the second bonding layer 32, and the liquid crystal cell 10 is bonded to the second glass plate 42 by the second bonding layer 32. Note that various known methods can be used for manufacturing the liquid crystal cell 10.
The second bonding layer 32 made of OCA is a bonding body containing a non-pressure-bonding adhesive component as described above. Therefore, the liquid crystal cell 10 and the second glass plate 42 are bonded without pressure (i.e., under environmental pressure (usually atmospheric pressure)). In addition, the second bonding layer 32 is bonded to the liquid crystal cell 10 and the second glass plate 42 at room temperature (e.g., 10° C. or higher and 30° C. or lower).

Next, as shown in FIG. 3(d), a stopper 35 is formed on the outer edge of the second bonding layer 32 on the second glass plate 42, spaced apart from the liquid crystal cell 10 and surrounding the outer periphery of the liquid crystal cell 10. The stopper 35 is formed by applying a liquid OCR material containing OCR using an application nozzle 51, and then curing the OCR material by irradiating it with ultraviolet light.

4A, a liquid OCR material (bonding material) 31A containing the OCR relating to the first bonding layer 31 is applied to the upper surface of the liquid crystal cell 10 (application step). A buffer member 50 is also disposed outside the second glass plate 42. More specifically, the buffer member 50 formed in a frame shape is disposed so as to surround the outer periphery of the second glass plate 42. Here, the OCR material (bonding material) 31A is applied to the entire area or a partial area of one side of the liquid crystal cell 10 and the adjustment member 20 by an application nozzle 51 such as a dispenser or a slit coater.
Then, as shown in FIG. 4B, the first glass plate 41 is placed on the buffer member 50 (placement step).
Each step shown in FIG. 4 is performed on a bonding apparatus 60 which will be described later.

The buffer member 50 is provided to dispose the first glass plate 41 in a spaced-apart state from the liquid crystal cell 10 disposed on the second glass plate 42 for an integration process using a bonding device, which will be described later. Therefore, in the manufacturing process of the liquid crystal device 1, the outer dimensions (length and width) of the first glass plate 41 are formed to be larger than those of the second glass plate 42. In other words, the outer dimensions (length or width, or length and width) of the second glass plate 42 are formed to be smaller than those of the first glass plate 41.
As a result, as shown in FIG. 4B, the first glass plate 41 can be disposed on the laminate made up of the second glass plate 42, the second bonding layer 32, and the liquid crystal cell 10 with the buffer member 50 interposed therebetween.

The thickness of the buffer member 50 is preferably formed so that the first glass plate 41 does not come into contact with the OCR material 31A applied onto the liquid crystal cell 10, and for example, the gap G between the OCR material 31A and the first glass plate 41 is preferably 100 μm or more. By providing a gap between the OCR material 31A and the first glass plate 41 in this way, it is possible to significantly prevent air (air bubbles) from remaining in the first bonding layer 31 that is formed when a vacuum is drawn by a bonding device in the integration process described below.

As described above, the cushioning member 50 of the present embodiment is formed in a frame shape surrounding the outer periphery of the second glass plate 42, but is not limited to this. As long as it is sufficient for practical use, the cushioning member 50 may be formed in various shapes, for example, in a shape that includes a partially interrupted portion, may be provided only at the corner portion of the first glass plate 41, or may be provided only at the straight portion of the first glass plate 41.
Furthermore, when the first glass plate 41 is placed on the cushioning member 50 as shown in FIG. 4(b), it is desirable to arrange it so that the width D of the portion that overlaps with the cushioning member 50 is, for example, 50 mm or more, although this depends on the external dimensions of the liquid crystal device 1.

The cushioning member 50 can be made of polyurethane foam, polyester, or the like, and is formed so that it can be sufficiently contracted by pressure from a diaphragm sheet in the bonding device described below, thereby holding the first glass plate 41 close to the liquid crystal cell 10.

Next, as shown in FIG. 4(c), the cushioning material 50 is contracted by pressing the diaphragm sheet with a bonding device described later, and the first glass plate 41 is brought closer to the liquid crystal cell 10, thereby integrating the first glass plate 41, the liquid crystal cell 10, and the second glass plate 42 (integration process).
As described above, the OCR material 31A is a liquid OCR material containing OCR, and is a bonding body containing a non-pressure-bonding adhesive component. Therefore, the first glass plate 41 is bonded to the liquid crystal cell 10 under environmental pressure (usually atmospheric pressure) without being pressurized. In addition, the first glass plate 41 is bonded to the liquid crystal cell 10 and the second bonding layer 32 of the second glass plate 42 at room temperature (for example, 10° C. or higher and 30° C. or lower).
Here, by pressing the diaphragm sheet, the OCR material 31A flows over the liquid crystal cell 10 and takes the form of the first bonding layer 31. Furthermore, the flowed OCR material 31A is largely prevented from leaking out to the outer periphery of the second bonding layer 32 by the stopper 35 provided on the outer edge of the second bonding layer 32.

Then, as shown in FIG. 5(a), the laminated second glass plate 42, second bonding layer 32, liquid crystal cell 10, layer of OCR material 31A, and first glass plate 41 are removed from the lamination device and irradiated with ultraviolet (UV) light to harden the layer of OCR material 31A. As the layer of OCR material 31A hardens, the first bonding layer 31 made of OCR is formed.

Thereafter, as shown in FIG. 5B, the buffer member 50 is removed, and the first glass plate 41 is cut to the same size as the second glass plate 42 along the cutting line L-L, thereby obtaining the liquid crystal device 1.
In the above explanation, the first glass plate 41 is cut to the size of the second glass plate 42, but it is not necessary to cut it to the size of the second glass plate 42 if necessary, and it is also not necessary to cut it to match the size of the second glass plate 42.

[Laminating device]
In the liquid crystal device 1 , the first glass plate 41 is bonded to a laminate of the second glass plate 42 and the liquid crystal cell 10 by a bonding device 60 .
6 and 7 are cross-sectional views showing this lamination apparatus.
As shown in Fig. 6(a), the laminating device 60 includes a table 61 on which the lamination objects are placed. Furthermore, the laminating device 60 is formed so that an upper case 62 is held so as to be freely opened and closed with respect to the table 61, and the table 61 together with the lamination objects is covered from above by the upper case 62 and sealed. The laminating device 60 is formed so that the internal space of the upper case 62 is divided by a diaphragm sheet 63 into a table side space AR1 close to the table 61 and an anti-table side space AR2 farther from the table 61, and the atmosphere of the table side space AR1 and the anti-table side space AR2 can be exhausted respectively. The diaphragm sheet 63 is a sheet material having sufficient flexibility, and is formed of, for example, silicon.

6A, in the bonding device 60, a laminate made up of the second glass plate 42, the second bonding layer 32, the stopper 35, and the liquid crystal cell 10 is placed on a table 61 together with a buffer member 50. In addition, an OCR material 31A for the first bonding layer 31 is applied to the liquid crystal cell 10 of the laminate (application step: FIG. 4A).
Thereafter, the first glass plate 41 is disposed on the cushioning member 50 (disposing step, FIG. 4(b)).

Next, as shown in FIG. 6(b), the upper case 62 covers the objects to be bonded from above, sealing them inside the bonding device 60. In this state, the bonding device 60 evacuates the atmosphere from the table side space AR1 and the anti-table side space AR2 and is held in a vacuum state, whereby the diaphragm sheet 63 is held close to the upper surface of the first glass plate 41 and facing this upper surface approximately parallel to it.

Here, in the past, in the bonding device, the first glass plate was attached to the table side surface of the diaphragm sheet using double-sided tape or the like without using the above-mentioned buffer member. Then, by closing the upper case, the first glass plate attached to the diaphragm sheet was placed on the liquid crystal cell, and the integration process was performed. However, as the liquid crystal device became larger, the first glass plate also became larger, and the weight of the first glass plate caused the first glass plate attached to the diaphragm sheet to fall, which could cause a problem such as damage to the first glass plate.
Therefore, in this embodiment, as described above, a buffer member 50 is provided and the first glass plate 41 is placed on top of the buffer member 50, thereby preventing the first glass plate from falling from the diaphragm sheet and being damaged, etc., as described above.

Next, as shown in Fig. 7(a), the table side space AR1 is maintained in a vacuum state, and the vacuum state of the counter table side space AR2 is returned to atmospheric pressure. As the counter table side space AR2 returns from a vacuum state to atmospheric pressure, the diaphragm sheet 63 deforms, and as shown in Fig. 7(b), the diaphragm sheet 63 deforms into a shape following the surface shape of the laminate of the first glass plate 41, the liquid crystal cell 10, and the second glass plate 42 arranged on the table 61, and presses the laminate of the first glass plate 41, the liquid crystal cell 10, and the second glass plate 42 with atmospheric pressure. At this time, the buffer member 50 contracts due to the pressure of the diaphragm sheet 63, and the first glass plate 41 is bonded to the liquid crystal cell 10 side via the OCR material 31A. At this time, the side surface of the buffer member 50 also contracts to match the outer shape of the first glass plate 41.
After the first glass plate 41 is bonded to the liquid crystal cell 10 without any gaps by the OCR material 31A using the bonding device 60, the laminate of the first glass plate 41, the liquid crystal cell 10, and the second glass plate 42 is removed from the bonding device 60 and irradiated with ultraviolet light as described above with reference to Fig. 5(a) to form the first bonding layer 31. Finally, as described above with reference to Fig. 5(b), the excess portion of the first glass plate 41 is cut off to complete the liquid crystal device 1. The irradiation of ultraviolet light may be performed while the plate is held on the table 61 of the bonding device 60.

According to the above configuration, by providing a buffer member 50 on the outside of the second glass plate 42 and placing and bonding the first glass plate 41 on this buffer member 50, it is possible to reduce damage to the glass plates when a liquid crystal device is created by placing a liquid crystal cell between the first and second glass plates.

In addition, in the bonding device 60, the atmosphere on the second glass plate 42 side of the diaphragm sheet 63 is exhausted, and the diaphragm sheet 63 is pressed by atmospheric pressure to contract the buffer member 50, thereby effectively avoiding localized pressure concentrations and appropriately contracting the buffer member, thereby reducing damage to the glass plate.

Furthermore, since a gap is formed between the first glass plate 41 placed on the buffer member 50 in the placement process and the OCR material 31A on the liquid crystal cell 10, when a vacuum is drawn by the bonding device in the integration process, it is possible to significantly prevent air (air bubbles) from remaining in the first bonding layer 31 that is formed.

Other Embodiments
The above describes in detail specific configurations suitable for implementing the present invention. However, the present invention allows the configurations of the above-described embodiments to be modified in various ways and even combined in various ways without departing from the spirit of the present invention.

REFERENCE SIGNS LIST 1 Liquid crystal device 10 Liquid crystal cell 14 Liquid crystal layer 24 Bead spacer 25 Sealing material 31 First bonding layer 31A OCR material 32 Second bonding layer 35 Stopper 36 Release film 41 First glass plate 42 Second glass plate 50 Cushioning member 51 Application nozzle 60 Bonding device 61 Table 62 Upper case 63 Diaphragm sheet

Claims (3)

A method for manufacturing a liquid crystal device including a first transparent substrate, a second transparent substrate having an outer shape smaller than that of the first transparent substrate, and a liquid crystal cell disposed between the first transparent substrate and the second transparent substrate, comprising:
a positioning step of positioning the first transparent substrate on a buffer member disposed outside the second transparent substrate so as to face the liquid crystal cell laminated on the second transparent substrate at a distance;
contracting the buffer member to bring the first transparent substrate closer to the liquid crystal cell, and integrating the first transparent substrate, the liquid crystal cell, and the second transparent substrate. The integration step includes:
The method for manufacturing a liquid crystal device according to claim 1 , further comprising the steps of: exhausting the atmosphere on the second transparent substrate side of a diaphragm sheet arranged to face the first transparent substrate, thereby pressing the diaphragm sheet with atmospheric pressure to contract the buffer member. a coating step of coating a bonding material on an upper surface of the liquid crystal cell laminated on the second transparent substrate;
The method for manufacturing a liquid crystal device according to claim 1 , wherein a gap is formed between the first transparent substrate placed on the buffer member in the placing step and the bonding material on the liquid crystal cell.

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