JPH1090667A - Liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an element which is light in weight and excellent in strength compared to a glass substrate having the same dimension and thickness as this element, and which has good optical characteristics such as retardation by interposing a liquid crystal layer between a pair of transparent substrates facing each other composed of a photosetting resin. SOLUTION: This display element is produced by inserting a liquid crystal layer between a pair of transparent substrates facing each other composed of a photosetting resin. This photosetting resin is a resin which is hardened by the irradiation of UV rays. Concretely, a resin compsn. comprising an acrylate compd. having radical reactive unsatd. compds., a resin compsn. comprising the acrylate compd. above described and a mercapto compd. having thiol groups, or a resin compsn. prepared by dissolving oligomers such as epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate in polyfunctional acrylate monomers can be used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device using a transparent substrate made of a photocurable resin. The liquid crystal display element of the present invention can be suitably used for, for example, an electronic organizer, a personal computer, a word processor, a touch panel, and the like.

[0002]

2. Description of the Related Art In a conventional liquid crystal display device, a glass substrate is generally used as a material capable of withstanding the high temperature processing step in the process of manufacturing the liquid crystal display device. However, when a glass substrate having a thickness of 1.0 mm or less is used for a liquid crystal display device, there is a problem that handling in a manufacturing process is difficult and the glass substrate is damaged during the manufacturing. This is more pronounced on the substrate. Therefore, in the case of a large-screen liquid crystal display element,
Although the breakage is prevented by increasing the thickness of the glass substrate, there is a problem that the substrate itself becomes heavier, and as a result, the liquid crystal display element becomes heavier.

In addition, recent technological developments have made it possible to use a liquid crystal display element made of a lightweight plastic sheet substrate because, for example, the temperature of the high-temperature processing step in the liquid crystal display element manufacturing process can be made low. Have been.
As such a plastic sheet substrate, it is excellent in optical characteristics represented by a retardation value and the like,
It is necessary to have excellent surface properties such as surface roughness. For example, JP-A-61-69028 and JP-A-4-208925 disclose resins having no optical anisotropy. A liquid crystal display device using a substrate made of polyether sulfone or the like has been proposed.

[0004] However, such a plastic sheet substrate has a problem that when the film thickness is as thin as about 0.1 mm, the film is not rigid and has poor flatness. For this reason, such a plastic sheet substrate is laminated or a thicker sheet is used in order to provide a firmness, but in this case, the retardation value increases, and the substrate is used as a substrate for a liquid crystal display element. Is inappropriate.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a liquid crystal display device using a good transparent substrate instead of a conventional glass substrate or plastic sheet substrate.

[0006]

The present invention for solving the above-mentioned problems relates to a liquid crystal display device characterized in that a liquid crystal layer is interposed between a pair of opposing transparent substrates made of a photocurable resin. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The photocurable resin constituting the transparent substrate made of the photocurable resin of the present invention is a resin that is cured by irradiation with ultraviolet rays or the like. Specifically, a resin composition comprising an acrylate compound having a radically reactive unsaturated compound, a resin composition comprising this acrylate compound and a mercapto compound having a thiol group, epoxy acrylate, urethane acrylate, polyester acrylate, polyether acrylate, etc. And the like, but are not limited thereto.

Among them, at least one selected from sulfur-containing bis (meth) acrylate represented by the formula (1) and alicyclic skeleton bis (meth) acrylate represented by the formula (2)
A composition comprising a kind of bis (meth) acrylate is preferable in terms of chemical resistance, rigidity and the like. “(Meth) acrylate” is a generic term for acrylate or methacrylate.

[0009]

Embedded image

[In the formula (1), R ¹ and R ² may be different from each other and represent a hydrogen atom or a methyl group. R ³ is a hydrocarbon group having 1 to 6 carbon atoms which may have an oxygen atom and / or a sulfur atom in the carbon chain, preferably 2 to 4 carbon atoms.
Represents an alkylene group. R ⁴ represents a hydrocarbon group having 1 to 6 carbon atoms which may have an oxygen atom and / or a sulfur atom in the carbon chain, preferably an alkylene group having 1 to 3 carbon atoms. X represents a halogen atom, an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms, and a represents an integer of 0 to 4. However, when a is an integer of 2 or more, a plurality of Xs may be different from each other. ]

Some examples of the compound represented by the above formula (1) are as follows. p-bis (β-methacryloyloxyethylthiomethyl) benzene, p-bis (β-acryloyloxyethylthiomethyl) benzene, m-bis (β-methacryloyloxyethylthiomethyl) benzene, m-bis (β-acryloyloxy) Ethylthiomethyl) benzene, p-bis (β-methacryloyloxyethyloxyethylthiomethyl) benzene,
p-bis (β-methacryloyloxyethylthioethylthiomethyl) benzene, p-bis (β-methacryloyloxyethylthiomethyl) tetrabromobenzene, m-
Bis (β-methacryloyloxyethylthiomethyl) tetrachlorobenzene. These compounds can be synthesized, for example, by the method disclosed in JP-A-62-195357.

[0012]

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[In the formula (2), R ⁵ and R ⁶ may be different from each other and represent a hydrogen atom or a methyl group. b represents 1 or 2, and c represents 0 or 1. ]

Some examples of the compound represented by the formula (2) are as follows. Bis (oxymethyl) tricyclo [5.2.1.0 ^2.6 ] decane = diacrylate, bis (oxymethyl) tricyclo [5.2.1.0
^2.6] decane = dimethacrylate, bis (oxymethyl) tricyclo [5.2.1.0 ^2.6] decane = acrylate methacrylate, bis (oxymethyl) pentacyclo [6.5.1.1 ^3.6 0 ^{2.7. 09.13} ] pentadecane diacrylate, bis (oxymethyl) pentacyclo [6.5.1.1. ^3.6 0 ^2.7 . 0 ^9.13 ] pentadecane dimethacrylate, bis (oxymethyl) pentacyclo [6.5.1.1. ^3.6 0 ^2.7 . 0 ^9.13 ] pentadecane acrylate methacrylate. These compounds can be synthesized, for example, by the method disclosed in JP-A-62-225508.

The (meth) acrylates represented by the above formulas (1) and (2) can be used alone or in combination of two or more. When the compound of the formula (1) is used alone, the low birefringence plate obtained according to the present invention has a refractive index of 1.54 to 1.65 at room temperature at a D line (589.3 mm) of sodium, and has a high refractive index. Having. When the compound of the formula (2) is used alone, the refractive index is relatively low, from 1.47 to 1.51. Therefore, a low birefringent plate having a desired refractive index between 1.47 and 1.65 can be obtained by using two or more compounds represented by the formulas (1) and (2) in combination.

For the transparent substrate, the above bis (meth) acrylate can be used by polymerizing it alone, but two or more bis (meth) acrylates can be used in the molecule represented by the following formulas (3), (4) and (5). At least one mercapto compound selected from mercapto compounds having a thiol group of 0.1 to 2 with respect to 80 to 99.1 parts by weight of bis (meth) acrylate.
0 parts by weight, more preferably 1 to 15 parts by weight, more preferably 5 to 10 parts by weight to reduce birefringence,
Appropriate toughness can be provided. When the amount of the mercapto compound exceeds 20 parts by weight, the heat resistance of the cured resin is lowered, which is not preferable.

[0017]

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[In the formula (3), a plurality of R ⁷ may be different from each other and each represents a methylene group or an ethylene group.
R ⁸ is 2 to 15 carbon atoms which may contain an oxygen atom and / or sulfur atom in the carbon chain, preferably a hydrocarbon residue of 2-6. d shows the integer of 2-6. ]

That is, the compound represented by the formula (3)
Diester to hexaester of thioglycolic acid or thiopropionic acid with a polyol. Some examples are pentaerythritol tetrakis (β-thiopropionate), pentaerythritol tetrakis (thioglycolate), trimethylolpropane tris (β-thiopropionate), and trimethylolpropane tris (thioglycolate). , Diethylene glycol bis (β-thiopropionate), diethylene glycol bis (thioglycolate), triethylene glycol bis (β-thiopropionate), triethylene glycol bis (thioglycolate), dipentaerythritol hexakis (β -Thiopropionate), dipentaerythritol hexakis (thioglycolate) and the like.

[0020]

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[In the formula (4), Y may be different from each other, and HS- (CH ₂ ) _e- (CO) (OCH ₂ -C
_{H 2) f - (CH 2} ) g - shows a. Here, e represents an integer of 1 to 4, f represents an integer of 1 to 4, and g represents an integer of 0 to 2, respectively. ]

That is, the compound of the formula (4) is a ω-SH group-containing triisocyanurate. Some examples are tris [2- (β-thiopropionyloxy)
Ethyl] isocyanurate, tris (2-thioglyconyloxyethyl) isocyanurate, tris [2- (β
-Thiopropionyloxyethoxy) ethyl] isocyanurate, tris (2-thioglyconyloxyethoxyethyl) isocyanurate, tris [3- (β-thiopropionyloxy) propyl] isocyanurate, tris (3-thioglyconyloxypropyl) ) Isocyanurate and the like.

[0023]

Embedded image

[In the formula (5), R ⁹ and R ¹⁰ may be different from each other and represent a hydrocarbon group having 1 to 3 carbon atoms. m and n each represent 0 or 1. p represents 1 or 2. ]

That is, the compound of the formula (5) is α, ω-S
It is an H group-containing compound. Some examples are benzene dimercaptan, xylylene dimercaptan,
4,4'-dimercaptodiphenyl sulfide and the like can be mentioned.

Other monomers used in the polymerization of the photocurable resin include, for example, methyl (meth) acrylate, phenyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, methacryloyloxymethyl Tetracyclododecane, methacryloyloxymethyltetracyclododecene, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 2,2-bis [4- (β- (Methacryloyloxyethoxy) phenyl] propane, 2,2′-bis [4- (β-methacryloyloxyethoxy) cyclohexyl] propane, 1,4-bis (methacryloyloxymethyl) cyclohexane, trimethylolpropane tri (meth) acrylate (Meth) acrylate compounds such as styrene, chlorostyrene, divinylbenzene, α
Core and / or side chain substituted and unsubstituted styrenes such as -methylstyrene. Among these other monomers, methacryloyloxymethylcyclododecane, 2,
2-bis [4- (β-methacryloyloxyethoxy)
Phenyl] propane, 2,2-bis [4- (β-methacryloyloxyethoxy) cyclohexyl] propane,
1,4-bis (methacryloyloxymethyl) cyclohexane and mixtures thereof are particularly preferred. Further, these may contain small amounts of antioxidants, ultraviolet absorbers, dyes and pigments, fillers and the like.

The bis (meth) acrylate or a mixture of the bis (meth) acrylate and the mercapto compound as described above is cured by a known radical polymerization in which a photopolymerization initiator which generates a radical by active energy rays such as ultraviolet rays is added. Let it. As the photopolymerization initiator used at that time, for example, benzophenone, benzoin methyl ether, benzoin isopropyl ether, diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethyl Benzoyldiphenylphosphine oxide and the like. Preferred photoinitiators are 2,4,6-trimethylbenzoyldiphenylphosphine oxide and benzophenone. Two or more of these photopolymerization initiators may be used in combination.

The addition amount of the photopolymerization initiator is 100
0.01 to 1 part by weight, preferably 0.02 part by weight based on part by weight
０．３0.3 parts by weight. If the amount of the photopolymerization initiator is too large, the polymerization proceeds rapidly, causing not only an increase in birefringence but also a deterioration in hue. If the amount is too small, the composition cannot be cured sufficiently.

The amount of the active energy ray to be irradiated is arbitrary as long as the photopolymerization initiator generates radicals. However, when the amount is extremely small, the heat resistance and mechanical properties of the cured product are poor due to incomplete polymerization. It is not sufficiently expressed, and conversely, if it is extremely excessive, it will deteriorate due to light such as yellowing of the cured product,
Ultraviolet rays of 200 to 400 nm are preferably used for 0.1 to 20 in accordance with the composition of the monomer and the kind and amount of the photopolymerization initiator.
Irradiate in the range of 0J. Specific examples of the lamp to be used include a metal halide lamp and a high-pressure mercury lamp.

For the purpose of promptly completing the curing, thermal polymerization may be used in combination. That is, the composition and the entire mold are usually heated in the range of 30 to 300 ° C. simultaneously with the light irradiation.
In this case, a radical polymerization initiator may be added in order to complete the polymerization better, but excessive use causes an increase in birefringence and a deterioration in hue. Specific examples of the thermal polymerization initiator include benzoyl peroxide, diisopropyl peroxy carbonate, t-butyl peroxy (2-ethylhexanoate), and the amount used is 1 part by weight or less based on 100 parts by weight of the monomer. Is preferred.

Further, after the radical polymerization by light irradiation is performed, the cured product is heated to reduce the completion of the polymerization reaction and the internal strain generated during the polymerization. The heating temperature is appropriately selected according to the composition of the cured product and the glass transition temperature. However, since excessive heating results in deterioration of the hue of the cured product, a temperature around the glass transition temperature or lower is preferable.

The method for molding a transparent substrate made of a photocurable resin is as follows.
Using two opposing flat plates (hereinafter referred to as “molding dies”),
The photocurable resin is injected into an injection mold in which a cavity is formed by a spacer or the like and the peripheral portion is sealed, and the photocurable resin is cured by irradiating active energy rays. The material of the mold, from the surface of the sheet after curing, preferably, using a polished glass, has sufficient transmittance of active energy rays to cure the photocurable resin, and does not easily deform its shape due to heat or the like Anything should do. Moreover, plastics, such as an acrylic plate, which can obtain surface properties equivalent to a polished glass are mentioned.

If necessary, a release agent or the like may be applied on the mold, or a release layer may be provided on the mold so as to facilitate the removal of the cured photocurable resin sheet from the mold. The release agent to be used, the release layer, and the application thereof are not particularly limited, but a substance having sufficient transmittance of active energy rays to cure the photocurable resin, and further, to cure the photocurable resin. Any substance may be used as long as it is a substance that does not easily change its state of formation due to active energy rays, heat generated at the time of curing, or the like, and can obtain a flatness comparable to that of a glass surface.

The active energy ray is for curing the photocurable resin, and includes, for example, ultraviolet rays. The irradiation amount of the active energy ray may be an amount that cures the photocurable resin to be used. The spacers and the like for forming the cavities are not particularly limited, as long as the desired sheet thickness can be obtained. For example, a plate or bar made of rubber or metal such as silicon rubber, or a plate or bar made of resin such as Teflon may be used. Further, a film may be formed on an opposite surface of a transparent substrate made of a photocurable resin with an acrylic resin or the like, for example, as a hard coat layer for preventing scratches.

The retardation value (R value) of the transparent substrate of the present invention is preferably 20 nm or less, particularly preferably 10 nm or less. If the thickness exceeds 20 nm, display irregularities tend to occur when characters or colors are displayed by being incorporated into a liquid crystal display device.

The thickness of the transparent substrate is preferably 100 to 2000 μm. If it is less than 100 μm, the sheet tends to bend under its own weight and tends to be inferior in flatness, and if it exceeds 2000 μm, it has the same weight as a glass substrate having a thickness of 1.5 to 0.7 mm and tends to be out of the purpose of weight reduction. . Further, the surface roughness Ra of the transparent substrate is preferably 0.05 μm or less. If the thickness exceeds 0.05 μm, when a process such as forming a conductive thin film on a transparent substrate is performed, the surface quality of the processed surface tends to be disturbed and the display quality tends to deteriorate. In particular, in an STN liquid crystal display element that requires fine uniform surface properties, the unevenness of the surface tends to hinder uniform alignment of the liquid crystal and significantly degrade the display quality.

The structure of the liquid crystal display element of the present invention may be the structure of a generally known liquid crystal display element. For example, a gas barrier layer may be formed on the opposing surfaces of a pair of transparent substrates made of a photocurable resin.
A transparent conductive film of indium tin oxide (ITO), an alignment film, an undercoat layer, etc. are sequentially formed, then a liquid crystal material is injected, sealed with a sealing member, and a polarizing plate is laminated on the outer surface. Thus, a liquid crystal display element can be formed.

[0038]

EXAMPLES Hereinafter, the contents and effects of the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the present invention. The transparent substrates obtained in the following Examples and Comparative Examples were measured and evaluated by the following methods.

<Surface Roughness (Ra)> Using a surface roughness measuring device (Surf Comb 575A, manufactured by Tokyo Seimitsu Co., Ltd.)
Diamond needle (1 μmR, 90 ° cone), measurement length 0.5 mm, cutoff value 0.16 mm, measurement speed 0.
The measurement was performed under the conditions of 06 mm / sec and linear correction.

<Retardation value (R value)> Automatic birefringence measuring device (ADR-150, manufactured by Oak Manufacturing Co., Ltd.)
N), the retardation value (R value) was measured by perpendicular incidence at a wavelength of 632.8 nm. <Weight> The weight of the transparent substrate was measured using a precision precision balance. <Sheet thickness> The thickness of the transparent substrate was measured using a thickness gauge.

Example 1 A cavity was formed using an optically polished glass flat plate (length 310 mm × width 410 mm × thickness 5 mm), a silicon plate 5 mm wide and 1 mm thick as a spacer, and the periphery was sealed with tape. To form an injection mold. 99 parts by weight of p-bis (β-methacryloyloxyethylthio) xylene as a photocurable resin, 1 part by weight of pentaerythritol tetrakis (β-thiopropionate), 2,4,6-trimethylbenzoyldiphenylphosphine oxide as a photoinitiator (Lucirin TP manufactured by BASF
O ") 0.05 parts by weight and benzophenone 0.02 parts by weight were uniformly stirred and mixed, followed by defoaming to obtain a composition. This composition was poured into a casting mold, and the distance from the glass surface was 400 mm.
UV light was applied for 30 minutes between the upper and lower metal halide lamps with an output of 80 W / cm for curing. The injection mold was removed to obtain a transparent substrate made of a photocurable resin.

The resulting transparent substrate made of a photocurable resin has a length of 300 mm × width 400 mm × thickness 1.0 mm, a surface roughness (Ra) of 0.004 μm, a retardation value (R value) of 8 nm and a weight of 150 g. there were. The weight of the transparent substrate made of the photocurable resin is the same shape and thickness of a commercially available optical glass substrate for a liquid crystal display element (density: about 2.5 g).
/ Cm ³ ), and the substrate had sufficient stiffness even with a thickness of 1.0 mm, and had good flatness.

Next, on the obtained transparent substrate made of a photocurable resin, SiO was deposited as an undercoat layer to a thickness of about 300 ° using SiO as a deposition material.
A transparent conductive film was formed by sputtering vapor deposition at 2,000 °. On this ITO transparent conductive film, a top coat layer and an alignment film were formed by spin-coating polyimide at about 500 °. Next, a liquid crystal material was injected, sealed with a sealing member, and a polarizing plate was further laminated on the outer surface to obtain a liquid crystal display element. No problem occurred in the manufacturing process. The liquid crystal display device thus obtained had the same performance as a liquid crystal display device using a glass substrate.

Example 2 Using an optically polished glass flat plate (length 310 mm × width 410 mm × thickness 5 mm), a cavity was formed using a Teflon plate having a width of 5 mm and a thickness of 0.5 mm as a spacer, and a peripheral tape was used. Sealed to form injection mold. Bis (oxymethyl) tricyclo [5.
2.1.0 ^2,6 ] decane = dimethacrylate 94 parts by weight, pentaerythritol tetrakis (β-thiopropionate) 6 parts by weight, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (BASF) as a photoinitiator 0.06 parts by weight of "Lucirin TPO" manufactured by
After uniformly stirring and mixing 0.04 parts by weight of benzophenone, the composition was defoamed to obtain a composition.

This composition was poured into a casting mold, and cured by irradiating ultraviolet rays for 30 minutes between metal halide lamps having an output of 80 W / cm above and below at a distance of 400 mm from the glass surface. The injection mold was removed to obtain a transparent substrate made of a photocurable resin. The resulting transparent substrate made of a photocurable resin had a length of 300 mm x a width of 400 mm x a thickness of 0.5 mm, a surface roughness (Ra) of 0.004 µm, a retardation value (R value) of 5 nm, and a weight of 75 g.

The weight of the transparent substrate made of a photocurable resin is
It is about 75 g lighter than a commercially available optical glass substrate for liquid crystal display elements of the same shape and thickness (density: about 2.5 g / cm ³ ), and this board has a sufficient waist even with a thickness of 0.5 mm. The flatness was also good. Next, on the obtained transparent substrate made of photocurable resin, SiO was deposited as an undercoat layer to a thickness of about 300 ° using SiO as a deposition material.
TO was sputter-deposited to a thickness of about 1000 ° to form a transparent conductive film. On this ITO transparent conductive film, a top coat layer and an alignment film were formed by spin-coating polyimide at about 500 °. Next, a liquid crystal material was injected, sealed with a sealing member, and a polarizing plate was further laminated on the outer surface to obtain a plastic sheet liquid crystal display element. No problem occurred in the manufacturing process. The liquid crystal display device thus obtained had the same performance as a liquid crystal display device using a glass substrate.

[0047]

The liquid crystal display element of the present invention uses a transparent substrate using a photocurable resin. Thereby, in the liquid crystal display device of the present invention, in addition to being lightweight and excellent in strength as compared with a glass substrate having the same shape and thickness, optical characteristics such as a retardation value are also good, and the liquid crystal display device or The weight of the liquid crystal display device itself can be reduced. Further, the production of the liquid crystal display element of the present invention is simple, the yield at the time of production is good, and the industrial utility value is extremely large.

Claims (6)

[Claims] 1. A liquid crystal display device comprising a liquid crystal layer interposed between a pair of opposing transparent substrates made of a photocurable resin. 2. A composition comprising a transparent substrate made of a photocurable resin containing at least one bis (meth) acrylate selected from the following formulas (1) and (2), cured by an active energy ray. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is a molded sheet. Embedded image [In the formula (1), R ¹ and R ² may be different from each other and represent a hydrogen atom or a methyl group. R ³ and R ⁴ may be different from each other and represent a hydrocarbon group having 1 to 6 carbon atoms which may have an oxygen atom and / or a sulfur atom in a carbon chain. X represents a substituent selected from a halogen atom, an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, and a represents an integer of 0 to 4. However, when a is an integer of 2 or more, a plurality of Xs may be different from each other. ] [In the formula (2), R ⁵ and R ⁶ may be different from each other and represent a hydrogen atom or a methyl group. b represents 1 or 2, and c represents 0 or 1. ] 3. A transparent substrate made of a photocurable resin comprises 80 to 99.9 parts by weight of at least one bis (meth) acrylate selected from the formulas (1) and (2) and the following formulas (3) and (3). A sheet formed by curing a composition comprising 0.1 to 20 parts by weight of at least one mercapto compound selected from 4) and (5) with an active energy ray. 2. The liquid crystal display device according to 2. Embedded image [In the formula (3), a plurality of R ⁷ may be different from each other, and each represents a methylene group or an ethylene group. R ⁸ represents a hydrocarbon residue having 2 to 15 carbon atoms which may contain an oxygen atom and / or a sulfur atom in the carbon chain. d shows the integer of 2-6. ] [In the formula (4), Y may be different from each other, and HS- (C
_{H 2) e - (CO)} (OCH 2 -CH 2) f - (C
H ₂ ) _g −. Where e is an integer of 1 to 4, f is 1 to 4
And g represents an integer of 0 to 2, respectively. ] [In the formula (5), R ⁹ and R ¹⁰ may be different from each other and represent a hydrocarbon group having 1 to 3 carbon atoms. m and n each represent 0 or 1. p represents 1 or 2. ] 4. The liquid crystal display device according to claim 1, wherein the retardation value of the transparent substrate made of a photocurable resin is 20 nm or less. 5. The liquid crystal display device according to claim 1, wherein the surface roughness Ra of the transparent substrate made of a photocurable resin is 0.05 μm or less. 6. The method according to claim 1, wherein the thickness of the transparent substrate made of a photocurable resin is 100 to 2000 μm.
6. The liquid crystal display device according to any one of items 5 to 5.