JP2003195035A - Substrate for display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for a display device which is excellent in visibility and has low view angle dependence. <P>SOLUTION: This substrate for a display device has a phase difference plate that satisfies Re (450)<Re (550)<Re (650), when the values of retardation (Re) in wavelengths 450 nm, 550 nm and 650 nm are defined as Re (450), Re (550) and Re (650), and an optical anisotropic layer that satisfies nz≥(nx+ny)/2, when the thickness of the optical anisotropic layer is defined as d, a refractive index in an in-plane lagging axial direction as nx, a refractive index in an in-plane phase-advancing axial direction as ny, and a refractive index in a thickness direction as nz. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a display device suitably used for a display device in various fields such as a personal computer, an AV device, a portable information communication device, a game and a simulation device, and an in-vehicle navigation system. Substrate.

[0002]

2. Description of the Related Art In a reflection type liquid crystal display device, particularly in an active matrix type TN (twisted nematic) mode, a retardation (Re) is provided in order to realize black and white, and to improve contrast and color. A wideband 1/4 phase difference plate having a wavelength of 1/4 is used.

However, in the 1/4 retardation plate, since the optical path length changes depending on the incident angle of light, there is a so-called "viewing angle dependency" in which the retardation value (Re) is different, resulting in poor visibility. There was a problem. In recent years, with the development of technology, a technology for applying a ¼ retardation plate to a large screen has been required, and a display device substrate having a high visibility without a viewing angle dependency is required in a wider range.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the various problems in the prior art and achieve the following objects. That is, an object of the present invention is to provide a substrate for a display device which has excellent visibility and has low viewing angle dependency.

[0005]

Means for solving the above-mentioned problems are as follows. That is, <1> wavelengths 450 nm, 550 nm, and 650 nm
Retardation (Re) value in Re (45
0), Re (550), and Re (650), Re (450) <Re (550) <Re (650)
A retardation film satisfying the following conditions and an optically anisotropic layer, the thickness of which is d, the refractive index in the in-plane slow axis direction is nx, the refractive index in the in-plane fast axis direction is ny, and the refractive index in the thickness direction. Is an optical anisotropic layer satisfying nz ≧ (nx + ny) / 2.

<2> A mode in which the retardation plate contains a resin having a positive intrinsic birefringence value and a negative resin, and a laminate of a layer made of a resin having a positive intrinsic birefringence value and a layer made of a negative resin. The substrate for a display device according to <1>, which is at least one of an aspect, an aspect which is a copolymer composition having a positive chain and a negative chain having an intrinsic birefringence value, and an aspect which includes a modified polycarbonate. Is. <3> The <1> or <2>, wherein the optically anisotropic layer contains a liquid crystal compound aligned in the thickness direction of the optically anisotropic layer.
The substrate for a display device described in <>. <4> The optically anisotropic layer according to any one of <1> to <3>, which is at least one of a biaxially stretched film and an unbalanced biaxially stretched film made of a resin having a negative intrinsic birefringence value. It is a substrate for a display device.

<5> The display device substrate according to any one of <1> to <3>, wherein the optically anisotropic layer contains a photoisomerizable compound. <6> Re [0] is the retardation of light incident in the normal direction to the display device substrate, and Re is the retardation of light incident at an angle inclined by θ degrees from the normal direction.
Let [θ] be the Re at wavelength 550 nm.
The display device substrate according to any one of <1> to <5>, wherein the value of [0] / Re [θ] is 0.93 to 1.07. <7> The retardation (Re) / wavelength (λ) value at wavelengths of 450 nm, 550 nm, and 650 nm of the retardation plate is 0.2 to 0.3.
6> The display device substrate according to any one of 6>.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The display device substrate of the present invention has a retardation plate and an optically anisotropic layer, and optionally other layers.

[Phase retarder] The retarder has a wavelength of 450
Re (450) <Re (5), where Re (450), Re (550) and Re (650) are the retardation values at nm, 550 nm and 650 nm, respectively.
50) <Re (650) is satisfied. In other words, it is necessary that the retardation value and the wavelength have a positive correlation. By having such a correlation, it is possible to provide a retardation plate which has a constant retardation characteristic with respect to incident light in the visible light region and which can be easily black-and-white and colored.

The wavelength of the retardation plate is 450 nm, 550
(Re) at nm and 650 nm
The value of / wavelength (λ) may vary somewhat depending on the properties of the liquid crystal used, but is preferably 0.2 to 0.3, more preferably 0.23 to 0.27, and 0.24 to
0.26 is more preferable. The retardation (R
When the value of e) / wavelength (λ) is within the above numerical range, it is possible to provide a quarter retardation plate having more uniform retardation characteristics with respect to incident light in the entire visible light range.

-Aspect of Retardation Plate- The material of the retardation plate is not particularly limited, and well-known materials (various resins and the like) usually used for retardation plates are preferably cited. For example, polyether sulfone (PE
S), polycarbonate (PC), polyarylate (P
Ar), norbornene polymers, polyesters, epoxy-butadiene copolymers, known polymers such as cellulosics, etc. may be mentioned. These may be used alone or in combination of two or more. Further, two or more kinds of these may be used to form a film having a laminated structure, or may be used as a copolymer composed of these monomers. Among these, polycarbonate-based (particularly modified polycarbonate-based) and the like are preferable in terms of transparency, birefringence value, and wavelength dispersion.

As a material for the retardation plate, a mode in which a resin having a positive intrinsic birefringence value and a resin having a negative intrinsic birefringence value are used in combination is preferable in that delicate wavelength dispersion can be adjusted. As such an aspect, "an aspect including a resin having a positive intrinsic birefringence value and a negative resin", "an aspect including a laminate of a layer made of a resin having a positive intrinsic birefringence value and a layer made of a negative resin And “an embodiment including a copolymer composition having a chain having a positive intrinsic birefringence value and a chain having a negative intrinsic birefringence value”.

<Aspect Containing Positive Resin and Negative Resin with Intrinsic Birefringence Value>-Resin with Positive Intrinsic Birefringence Value ---- Aspect Containing Resin with Positive Intrinsic Birefringence Value and Negative Resin In the invention, "in the same layer, a resin having a positive intrinsic birefringence value and a resin having a negative intrinsic birefringence value" is referred to.), The resin having a positive intrinsic birefringence value has a uniaxial orientation rule in the molecule. It is a resin having a characteristic of exhibiting optically positive uniaxiality when given. Examples of the resin include polyolefin-based resins (eg, polyethylene, polypropylene, norbornene-based polymers, etc.), polyester-based resins (eg, polyethylene terephthalate, polybutylene terephthalate, etc.), polyarylene sulfide-based resins (eg, polyphenylene sulfide, etc.). , Polyvinyl alcohol resins, polycarbonate resins, polyarylate resins, cellulose ester resins (some of which have a negative intrinsic birefringence value), polyethersulfone resins, polysulfone resins, polyallylsulfone resins, Examples thereof include polyvinyl chloride resins, and multi-component (binary, ternary, etc.) copolymer resins thereof. These may be used alone or in combination of two or more. In the present invention, of these, polycarbonate resins, norbornene resins, polyether sulfone resins and the like are preferable in terms of heat resistance, transparency and the like.

--Resin having a negative intrinsic birefringence value-- The resin having a negative intrinsic birefringence value has a characteristic of exhibiting optically negative uniaxiality when a uniaxial orientation rule is given to a molecule. Examples of the resin include: polystyrene-based resin, polyacrylonitrile-based resin, polymethylmethacrylate-based resin, and multi-component (binary, ternary, etc.) copolymer resins thereof. These may be used alone or in combination of two or more. In the present invention,
Among these, a styrene-based resin or the like is preferable in terms of birefringence manifestation, and a copolymer of styrene and maleic anhydride is more preferable in terms of heat resistance.

It is preferable that the resin having a positive intrinsic birefringence value and the resin having a negative intrinsic birefringence value have greatly different wavelength dispersions from each other, and it is preferable that both the retardation (Re) are highly developable.

As the resin having a negative intrinsic birefringence value and a large expression of retardation (Re), a styrene-based material is particularly preferable. Since the styrene-based material has a large wavelength dispersion, a resin having a small wavelength dispersion is preferably used as the resin having a positive intrinsic birefringence value to be combined. Examples of the resin having a small wavelength dispersion include polymers such as olefin-based and polyvinyl alcohol-based resins, and cycloolefin-based resins such as norbornene-based resins are particularly preferable in terms of heat resistance, dimensional stability, and the like. .

--Other components-- In the above-mentioned "embodiment containing a resin having a positive intrinsic birefringence value and a resin having a negative intrinsic birefringence value", other components such as a compatibilizer may be included unless the effects of the present invention are impaired. Can be included. The compatibilizer can be preferably used when the intrinsic birefringence value is mixed with a resin having a positive value and a resin having a negative value, and when phase separation occurs, the intrinsic birefringence value is a positive value. It is possible to improve the mixed state of the resin and the negative resin.

--Manufacturing Method-- There is no particular limitation on the method of manufacturing the retardation plate in the embodiment containing the resin having a positive intrinsic birefringence value and the resin having a negative value.
It can be appropriately selected according to the purpose. For example, the intrinsic birefringence value is appropriately selected from positive resin and negative resin,
Determine the blending ratio, add the compatibilizer and the like if necessary,
These are compounded. After that, the composition is formed into a film or sheet according to a solution film forming method in which the composition is applied and dried and then formed, or an extrusion forming method in which the mixture is pelletized, melt-extruded and formed, and the like and stretched to form a letter. The retardation plate is manufactured by controlling the value of the retardation (Re) within the above numerical range. Suitable examples of the stretching include longitudinal uniaxial stretching for stretching in the mechanical flow direction and lateral uniaxial stretching for stretching in the direction orthogonal to the mechanical flow direction (for example, tenter stretching), but if there is some It may be axial stretching.

<Aspect Including Laminated Body> The laminated body is a laminated body of a layer made of a resin having a positive intrinsic birefringence value and a layer made of a negative resin. As the resin having a positive intrinsic birefringence value and the resin having a negative value, the same resins as those described above are preferably mentioned, and the particularly preferable resins are also the same. As long as the effects of the present invention are not impaired, the "embodiment including a laminate" includes an adhesive layer capable of favorably adhering a layer made of a resin having a positive intrinsic birefringence value and a layer made of a negative resin. You can leave.

--Manufacturing Method-- The method for manufacturing the retardation plate in the embodiment including the laminate is not particularly limited, but the intrinsic birefringence value is positive in that the laminate is easily manufactured. A method of forming a resin and a negative resin by coextrusion is preferable. In the co-extrusion, for example, the intrinsic birefringence value is positive resin, negative resin,
And, if desired, the resin for the adhesive layer can be introduced into the extrusion die, and each polymer can be brought into contact with the inside of the die or the opening of the die to integrate them to form a laminate.

The die is not particularly limited, but T
A die can be preferably used, and the internal shape of the T die is not particularly limited and various shapes can be mentioned. If desired, the extruded molten laminate may be stretched over a plurality of rolls and moved by following the rotation of the rolls to adjust the thickness of the laminate to a desired thickness.

FIG. 1 is a schematic block diagram of a coextrusion apparatus preferably used for the coextrusion. The co-extrusion device 20 includes an extrusion die 22, extruders 24 and 26, and a tension roll 2.
It has 8, 30, 32. In the co-extrusion device 20, the resin having a positive intrinsic birefringence value and the resin having a negative intrinsic birefringence value, which are stored in the extruder 24 and the extruder 26, are introduced into the extrusion die 22 and merge at the opening of the extrusion die 22. , The resins are brought into contact with each other to be integrated with each other to form the laminated body 34. When the adhesiveness between the resin having a positive intrinsic birefringence value and the resin having a negative intrinsic birefringence value is poor, an extruder for forming an adhesive layer may be further provided. The formed laminated body 34 is stretched by rotating tensioning rolls 28, 30, 32, moves following the rotation of the tensioning rolls 28, 30, 32, and is adjusted to a desired thickness to form a film or sheet. The retardation film is formed into a shape and appropriately stretched to control the retardation (Re) value within the above numerical range to produce a retardation plate. As the stretching, "stretching" described above
The same stretching as is all mentioned.

<Aspect Containing Copolymerization Composition> --Copolymerization Composition-- The copolymerization composition is a copolymerization composition having a chain having a positive intrinsic birefringence value and a chain having a negative intrinsic birefringence value. A copolymer composition of a monomer that constitutes a resin having a positive birefringence value and a monomer that constitutes a negative resin is particularly preferable. The copolymer composition is not particularly limited, but a graft copolymer having a main chain and a graft chain graft-bonded to the main chain is preferred, and the main chain has a positive intrinsic birefringence value. It is particularly preferable that the graft chain is a chain composed of a monomer constituting the resin, and the graft chain is a chain composed of a monomer constituting the resin having a negative intrinsic birefringence value. As the resin having a positive intrinsic birefringence value and the resin having a negative value, the same resins as those described above are all preferably mentioned, and the particularly preferable resins are also the same.

The method for producing the graft copolymer is not particularly limited, and bulk polymerization, precipitation polymerization, emulsion polymerization,
Well-known polymerization methods such as solution polymerization and suspension polymerization are preferred. Among these, suspension polymerization or solution polymerization is preferable.

Regarding the suspension polymerization method, for example, refer to the method described in "Experimental Method of Polymer Synthesis" (Takayuki Otsu, Masayoshi Kinoshita, Kagaku Dojinsha), pages 130 and 146 to 147. can do.

According to the suspension polymerization, the graft copolymer is obtained by an addition polymerization reaction initiated by an oil-soluble initiator using an aqueous dispersion medium in the presence of inorganic salts and / or a water-soluble resin dispersant. , 50 μm or more.

The above-mentioned inorganic salts are used for the purpose of stabilizing dispersion and preventing water-solubilization of monomers and the like.
For example, sodium chloride, potassium chloride, calcium chloride, magnesium chloride, ammonium chloride, potassium sulfate, calcium sulfate, magnesium sulfate, ammonium sulfate, potassium aluminum sulfate, sodium carbonate, potassium carbonate, calcium hydrogen phosphate and the like can be mentioned.

Examples of the water-soluble resin dispersant include:
Polyvinyl alcohol, sodium polyacrylate, styrene-alkali hydrolyzate of maleic anhydride copolymer (for example, "Isoban" manufactured by Kuraray Co., Ltd.), sodium alginate and water-soluble cellulose derivative ("Meiprogut" manufactured by Sansho Co., Ltd.), "Kelco SCS", "Quargum",
"MH-K" manufactured by Hoechst Japan Co., Ltd.) and the like.

The polymerization initiator used in the suspension polymerization is preferably a water-insoluble and oil-soluble polymerization initiator, and examples thereof include azobis (cyclohexane-1-carbonitrile), azobisisobutyronitrile and 2,2. '-Azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2'-azobisisobutyrate, benzoyl peroxide, lauroyl peroxide. Peroxide-t-butyl,
Peroxide-t-amyl, cumyl peroxide, t-butyl peroxide benzoate, t-butyl peroxide phenylacetate,
Etc. Among these, peroxide-based polymerization initiators are preferable.

The polymerization temperature in the graft polymerization varies depending on the kind of the monomer to be graft-polymerized, the boiling point, the ceiling temperature (the temperature at which the polymerization and the depolymerization reach equilibrium), etc., but cannot be specified unconditionally. , Usually 0 to 100 ° C, preferably 40 to 90 ° C.

--Other Components-- In the above-mentioned "embodiment containing the copolymer composition", other components such as the above-mentioned compatibilizer may be contained unless the effects of the present invention are impaired. .

--Production Method-- The method for producing the retardation plate in the embodiment containing the copolymer composition is not particularly limited and can be appropriately selected depending on the purpose. For example, the intrinsic birefringence value is appropriately selected a monomer that constitutes a positive resin (monomer) and a monomer that constitutes a negative resin, and if desired, a compatibilizer or the like is added,
These are compounded. Then, thereafter, this composition is formed into a film or sheet according to a solution film-forming method of forming a solution by applying and drying, or an extrusion forming method of forming by pelletizing, melt-extruding, and the like, By appropriately stretching, the retardation (Re) value is controlled within the above numerical range, and a retardation plate is manufactured. Preferable examples of the stretching include the same stretching as the above-mentioned "stretching".

-Physical Properties of Retardation Plate- The photoelasticity of the retardation plate is preferably 20 Brewster or less, more preferably 10 Brewster or less.
Blue star or less is more preferable. The photoelasticity is 20
If it exceeds the Brewster's level, birefringence may occur when stress is applied at the time of manufacturing a substrate for a display device, and an unfavorable phenomenon such as reduction in contrast may occur. The thickness of the retardation plate is not particularly limited, but is 30 to 3
00 μm is preferable, and 50 to 200 μm is more preferable.

[Optically Anisotropic Layer] The thickness of the optically anisotropic layer is d, the refractive index in the in-plane slow axis direction is nx, the in-plane fast axis direction is ny, and the thickness direction is When the refractive index is nz, nz ≧ (nx + ny) / 2 is satisfied.

By satisfying the above conditions, the optically anisotropic layer has a constant retardation value (Re) regardless of the incident angle of light, has a low viewing angle dependency, and is excellent in visibility. A substrate for a display device can be provided.

As the above-mentioned optically anisotropic layer, nz is preferably as close as possible to the value of (nx + ny) / 2, and it is particularly preferable that nz = (nx + ny) / 2 is satisfied, since the viewing angle dependence is small.

In the optically anisotropic layer, the retardation (Re) is represented by the product of the birefringence value (Δn) and the layer thickness (d). Here, if the incident angle of light to the layer deviates from the vertical direction, the optical path length increases, and the layer thickness (d) increases. Therefore, in order to keep the value of retardation (Re) constant irrespective of the change in viewing angle, the value of birefringence value (Δn) is decreased, that is, the refractive index nz in the thickness direction of the optically anisotropic layer. By increasing the value of, the viewing angle dependence of the display device substrate can be reduced. As such an optically anisotropic layer, for example, a first embodiment containing a liquid crystalline compound aligned in the thickness direction of the optically anisotropic layer (may be referred to as “vertical alignment” in the present invention). The second aspect, which is at least one of a biaxially stretched film and an unbalanced biaxially stretched film made of a resin having a negative intrinsic birefringence value, a third aspect including a photoisomerizable compound, and the like are preferable.

-First Mode- In the first mode, as the liquid crystal compound,
Examples thereof include rod-like liquid crystal compounds and discotic liquid crystal compounds. As the rod-shaped liquid crystalline compound, a rod-shaped liquid crystalline compound having a nematic orientation is particularly preferable.

As the nematically oriented rod-shaped liquid crystalline compound, all nematically oriented liquid crystalline compounds composed of known liquid crystalline molecules can be preferably cited. Examples thereof include azomethines, azoxys, cyanobiphenyls and cyanophenyl. Preferable examples thereof include esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyridines, phenyldioxanes, tolans, alkenylcyclohexylbenzonitriles, and the like. Exemplary compounds of the liquid crystalline molecule are shown in the following structural formulas (a) to (v). Among these, a liquid crystal compound composed of a polymerizable liquid crystal molecule is particularly preferable because it can be immobilized by a polymerization reaction.

[0040]

[Chemical 1]

[0041]

[Chemical 2]

[0042]

[Chemical 3]

In the structural formulas (s) and (t) in the exemplified compound of the liquid crystal molecule, n represents an integer of 3 or more.

As the discotic liquid crystalline compound, various references (C. Destrade et al.
l. , Mol. Crysr. Liq. Crys
t. , Vol. 71, page 111 (198
1); Chemical Society of Japan, Quarterly Chemistry Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10, Section 2 (1994);
Kohne et al. , Angew. Che
m. Soc. Chem. Comm. , Page
1794 (1985); Zchange a
l. , J. Am. Chem. Soc. , Vo
l. 116, page 2655 (1994)).

The discotic liquid crystalline compound is preferably fixed by polymerization. The polymerization is described in, for example, JP-A-8-27284, and examples thereof include a method in which a polymerizable group as a substituent is bonded to a discotic core of a discotic liquid crystalline molecule to perform polymerization. However, in this method, when the polymerizable group is directly bonded to the disk-shaped core, it becomes difficult to maintain the alignment state in the polymerization reaction. Therefore, it is preferable to introduce a linking group between the discotic core and the polymerizable group. Therefore, as the discotic liquid crystal molecule having a polymerizable group, a compound represented by the following formula (I) is preferable.

Formula (I): D (-LP) _{n In} formula (I), D is a disk-shaped core, L is a divalent linking group, P is a polymerizable group, and n is It is an integer of 4 to 12.

Specific examples of the disk-shaped core (D) of the formula (I) are shown below ((D1) to (D15)). In the following specific examples (D1) to (D15), LP (or PL)
Means a combination of a divalent linking group (L) and a polymerizable group (P).

[0048]

[Chemical 4]

[0049]

[Chemical 5]

[0050]

[Chemical 6]

[0051]

[Chemical 7]

[0052]

[Chemical 8]

[0053]

[Chemical 9]

[0054]

[Chemical 10]

[0055]

[Chemical 11]

[0056]

[Chemical 12] (D15)

In the formula (I), the divalent linking group (L) is an alkylene group, an alkenylene group, an arylene group, -CO-, -NH-, -O-, -S-, or a combination thereof. A divalent linking group selected from the group consisting of is preferred, and a group combining at least two divalent groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, -CO- and -O- is particularly preferred. .

The number of carbon atoms of the alkylene group is
1-12 are preferable. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6-10. The alkylene group, alkenylene group, and arylene group are further an alkyl group,
It may be substituted with a cyano group, an alkoxy group, an acyloxy group, and a substituent such as a halogen atom.

Specific examples (L1 to L25) of the divalent linking group (L) in the formula (I) are shown below. The left side is bound to the discotic core (D), and the right side is bound to the polymerizable group (P). In specific examples (L1 to L25), AL is an alkylene group or an alkenylene group, and AR is an arylene group.

L1: -AL-CO-O-AL- L2: -AL-CO-O-AL-O- L3: -AL-CO-O-AL-O-AL- L4: -AL-CO-O-AL-O-CO- L5: -CO-AR-O-AL- L6: -CO-AR-O-AL-O- L7: -CO-AR-O-AL-O-CO- L8: -CO-NH-AL- L9: -NH-AL-O- L10: -NH-AL-O-CO-

L11: -O-AL- L12: -O-AL-O- L13: -O-AL-O-CO- L14: -O-AL-O-CO-NH-AL- L15: -O- AL-S-AL-L16: -O-CO-AL-AR-O-AL-O-CO
-L17: -O-CO-AR-O-AL-CO- L18: -O-CO-AR-O-AL-O-CO- L19: -O-CO-AR-O-AL-O-AL- O-
CO-L20: -O-CO-AR-O-AL-O-AL-O-
AL-O-CO-L21: -S-AL- L22: -S-AL-O- L23: -S-AL-O-CO- L24: -S-AL-S-AL- L25: -S-AR -AL-

The polymerizable group (P) in formula (I) is determined according to the type of polymerization reaction. Specific examples ((P1) to (P18)) of the polymerizable group (P) are shown below.

[0063]

[Chemical 13]

[0064]

[Chemical 14]

[0065]

[Chemical 15]

[0066]

[Chemical 16]

[0067]

[Chemical 17]

[0068]

[Chemical 18]

In the formula (I), as the polymerizable group (P), an unsaturated polymerizable group (in the above specific examples, (P1),
(P2), (P3), (P7), (P8), (P1
5), (P16), and (P17), and an epoxy group (in the specific example, (P6) and (P1)
8)) is preferable, an unsaturated polymerizable group is more preferable, and an ethylenically unsaturated polymerizable group (in the above specific example, (P
1), (P7), (P8), (P15), (P16),
And (P17)) are the most preferable.

In the formula (I), n is an integer of 4 to 12, and is specifically determined according to the type of discotic core (D). The combination of a plurality of L and P may be different, but is preferably the same.
These discotic liquid crystal molecules may be used alone or in combination of two or more (for example, a molecule having an asymmetric carbon atom in a divalent linking group and a molecule having no asymmetric carbon atom are used in combination).
You may.

In the first aspect, by vertically aligning the liquid crystalline molecules, the value of the refractive index nz in the thickness direction of the optically anisotropic layer is increased, the viewing angle dependency is low, and the visibility is improved. It is possible to provide an excellent display device substrate. As a method of vertically aligning the liquid crystal molecules, for example, a liquid coating composition containing the liquid crystal molecules, a polymerization initiator, and optionally other additives is applied on the vertical alignment film. Is preferred.

As a solvent used for preparing the coating solution, an organic solvent is preferable, and specifically, an amide (eg:
N, N-dimethylformamide etc.), sulfoxide (eg dimethyl sulfoxide etc.), heterocyclic compound (eg pyridine), hydrocarbon (eg benzene, hexane etc.), alkyl halide (eg chloroform, dichloromethane etc.), ester (Example: methyl acetate, butyl acetate, etc.), ketone (Example: acetone, methyl ethyl ketone, etc.), ether (Example: tetrahydrofuran, 1,2-dimethoxyethane, etc.) and the like. Of these, alkyl halides and ketones are preferable. These may be used alone or in combination of two or more. The coating solution is applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method, etc.)
Can be done by.

It is preferable that the liquid crystal molecules aligned vertically are fixed while maintaining the alignment state. Examples of the polymerization reaction include a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, and the photopolymerization reaction is preferable.

Examples of the photopolymerization initiator include α-carbonyl compounds (US Pat. Nos. 2,367,661 and 2,367,767).
No. 0 each compound), an acyloin ether (a compound described in US Pat. No. 2,448,828), an α-hydrocarbon-substituted aromatic acyloin compound (a compound described in US Pat. No. 2,722,512). Compound),
Polynuclear quinone compounds (US Pat. Nos. 3,046,127, 29)
51758), combinations of triarylimidazole dimers and p-aminophenyl ketone (compounds described in U.S. Pat. No. 3,549,367), acridine and phenazine compounds (JP-A-60). -105667, US Patent 423
9850) and oxadiazole compounds (compounds described in U.S. Pat. No. 4,212,970).

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by weight, more preferably 0.5 to 5% by weight, based on the solid content of the coating liquid. In the light irradiation for polymerizing the discotic liquid crystal molecules, it is preferable to use ultraviolet rays. The irradiation energy is 2
0 mJ / cm ^{2 to} 50 J / cm ² is preferable, and 100 to
800 mJ / cm ² is more preferable. Light irradiation may be carried out under heating conditions in order to accelerate the photopolymerization reaction.

In order to vertically align the liquid crystal molecules, it is preferable to prepare an alignment film having a low surface energy as the vertical alignment film. Specifically, it is preferable that the functional group of the polymer lowers the surface energy of the alignment film, so that the discotic liquid crystal molecules and the like are vertically erected. As the functional group, a fluorine atom and a hydrocarbon group having 10 or more carbon atoms are preferable.

From the viewpoint of allowing the fluorine atom or the hydrocarbon group to exist on the surface of the alignment film, it is preferable to introduce the fluorine atom or the hydrocarbon group into the side chain rather than into the main chain of the polymer. The content of fluorine in the polymer is 0.
05-80 wt% is preferable, 0.1-70 wt% is more preferable, 0.5-65 wt% is further preferable, 1-
Most preferred is 60% by weight.

The hydrocarbon group is preferably, for example, an aliphatic group, an aromatic group, or a combination thereof. Examples of the aliphatic group include cyclic, branched, and linear groups, and examples thereof include an alkyl group (which may be a cycloalkyl group) and an alkenyl group (which may be a cycloalkenyl group). To be The hydrocarbon group may have a substituent such as a halogen atom which does not exhibit strong hydrophilicity. The number of carbon atoms in the hydrocarbon group is preferably 10 to 100, more preferably 10 to 60, and even more preferably 10 to 40.

The main chain of the polymer preferably has a polyimide structure or a polyvinyl alcohol structure.

Generally, the polyimide is preferably synthesized by a condensation reaction of tetracarboxylic acid and diamine. A polyimide corresponding to a copolymer may be synthesized by using two or more kinds of tetracarboxylic acids or two or more kinds of diamines. The fluorine atom and the hydrocarbon group are present in the repeating unit originating from tetracarboxylic acid,
It may be present in the repeating unit derived from the diamine or in both repeating units. When a hydrocarbon group is introduced into the polyimide, it is particularly preferable to form a steroid structure on the main chain or side chain of the polyimide. The steroid structure existing in the side chain corresponds to a hydrocarbon group having 10 or more carbon atoms and has a function of vertically aligning liquid crystal molecules. In the present invention, the steroid structure means a cyclopentanohydrophenanthrene ring structure or a part of a bond of the ring is an aliphatic ring (a range not forming an aromatic ring).
Refers to a ring structure that is a double bond.

As the polyvinyl alcohol, fluorine-modified polyvinyl alcohol, modified polyvinyl alcohol having a hydrocarbon group having 10 or more carbon atoms, and the like are preferable.

The fluorine-modified polyvinyl alcohol contains 5 to 80 mol% of repeating units containing a fluorine atom.
It is preferably contained, and more preferably 7 to 70 mol%. A preferable fluorine-modified polyvinyl alcohol is represented by the following formula (PV1).

Formula (PV1)-(VA1) x- (FRU) y- (VAc) z- In the formula (PV1), VAl is a vinyl alcohol repeating unit and FRU is a repeating unit containing a fluorine atom. , VAc is a vinyl acetate repeating unit, x
Is 20 to 95 mol% (preferably 24 to 90 mol%)
And y is 5 to 80 mol% (preferably 7 to 70 mol%) and z is 0 to 30 mol% (preferably 2 to 2).
0 mol%). Repeating units (FRU) containing a preferred fluorine atom are represented by the following formulas (FRU-I) and (FRU).
-II).

[0084]

[Chemical 19]

In formulas (FRU-I) and (FRU-II)
By the way, Rf¹And Rf^TwoAre fluorine-substituted hydrocarbons
And an alkylene group and an arylene group are fluorine radicals.
It may be replaced by a child. L¹  Is -O-,-
CO-, -SO_Two-, -NH-, alkylene group, aryl
A divalent group selected from a len group and a combination thereof.
It is a linking group. L^Two  Is a single bond, -O-, -CO-,
-SO_Two  -, -NH-, alkylene group, arylene
Groups and divalent linkages selected from combinations thereof
It is a base. A divalent string formed by the above combination.
Consolidation (L¹And L ^Two) Specific examples (L26 to L34),
It is shown below.

L26: -O-CO- L27: -O-CO-alkylene group -O- L28: -O-CO-alkylene group -CO-NH- L29: -O-CO-alkylene group -NH-SO ₂ -Arylene group-O-L30: -Arylene group-NH-CO-L31: -Arylene group-CO-O-L32: -Arylene group-CO-NH-L33: -Arylene group-O-L34: -O-CO -NH-arylene group-NH-CO
−

In the fluorine-substituted hydrocarbon group, examples of the hydrocarbon group include aliphatic groups, aromatic groups, and combinations thereof. The aliphatic group is cyclic,
It may be branched or linear, but is preferably an alkyl group (may be a cycloalkyl group), an alkenyl group (may be a cycloalkenyl group), or the like.
The aliphatic group may have a substituent that does not exhibit strong hydrophilicity, such as another halogen atom, in addition to the fluorine atom.
The number of carbon atoms in the hydrocarbon group is 1 to 100
Is preferred, 2-60 is more preferred, and 3-40 is even more preferred. In the hydrocarbon group, the proportion of hydrogen atoms substituted with fluorine atoms is preferably 50 to 100 mol%, more preferably 70 to 100 mol%, and 80 to
100 mol% is more preferable, and 90 to 100 mol% is the most preferable.

In the modified polyvinyl alcohol having a hydrocarbon group having 10 or more carbon atoms, the hydrocarbon group is preferably an aliphatic group, an aromatic group, or a combination thereof. The aliphatic group may be cyclic, branched or linear and is preferably an alkyl group (which may be a cycloalkyl group) or an alkenyl group (which may be a cycloalkenyl group). The hydrocarbon group may have a substituent such as a halogen atom which does not exhibit strong hydrophilicity. The number of carbon atoms in the hydrocarbon group is preferably 10 to 100, more preferably 10 to 60, and even more preferably 10 to 40. The modified polyvinyl alcohol having a hydrocarbon group has 10 carbon atoms.
It is preferable that the repeating unit having the above hydrocarbon group is contained in the range of 2 to 80 mol%, and more preferably 3 to 70 mol%. A modified polyvinyl alcohol having a hydrocarbon group having 10 or more carbon atoms is preferably represented by the following formula (P
It is represented by V2).

(PV2)-(VAl) x- (HyC) y- (VAc) z- In the formula, VAl is a vinyl alcohol repeating unit, and HyC has a hydrocarbon group having 10 or more carbon atoms. It is a repeating unit, VAc is a vinyl acetate repeating unit, and x is 20 to 95 mol% (preferably 25%).
~ 90 mol%), y is 2 to 80 mol% (preferably 3 to 70 mol%), and z is 0 to 30 mol% (preferably 2 to 20 mol%).

A repeating unit (HyC) having a hydrocarbon group having 10 or more carbon atoms is preferably represented by the following formula (HyC
-I) and (HyC-II).

[0091]

[Chemical 20]

Formulas (HyC-I) and (HyC-II)
Medium, R¹  And R^Two  Each has 10 or more carbon atoms
It is a hydrocarbon group. L¹Is -O-, -CO-, -SO
_Two  -, -NH-, alkylene group, arylene group, and
And a divalent linking group selected from a combination thereof.
L^Two  Is a single bond, -O-, -CO-, -SO_Two  
-, -NH-, an alkylene group, an arylene group, and
It is a divalent linking group selected from these combinations. Up
A divalent linking group (L ¹Over
And L^TwoSpecific examples of) are the above formulas (FRU-I) and (FR
It is the same as the specific example shown in U-II).

The degree of polymerization of the polymer used in the vertical alignment film is preferably 200 to 5,000, and 300 to 30.
00 is more preferable. The molecular weight of the polymer is 9
000-200000 is preferable and 13000-130
000 is more preferable. These polymers may be used alone or in combination of two or more.

When forming the vertical alignment film, it is preferable to perform rubbing treatment. The rubbing treatment is preferably performed by rubbing the surface of the above-mentioned polymer-containing film with paper or cloth several times in a certain direction. In addition, by using the above-mentioned vertical alignment film, the liquid crystal molecules are vertically aligned, and then the liquid crystal molecules are fixed in the alignment state to form the optically anisotropic layer, and only the optically anisotropic layer is formed. It may be transferred onto the retardation plate.

—Second Mode— In the second mode, the resin having a negative intrinsic birefringence value is the “resin having a negative intrinsic birefringence value” described in the section of the “retarder”. The same thing can be preferably mentioned.

When the optically anisotropic layer is at least one of a biaxially stretched film and an unbalanced biaxially stretched film made of a resin having a negative intrinsic birefringence value, each refraction in the optically anisotropic layer is In the relationship between the refractive indices (refractive index in the in-plane slow axis direction = nx, refractive index in the in-plane fast axis direction = ny, refractive index in the thickness direction = nz), refractive index nz in the thickness direction
Both values are large (for biaxially stretched film:
nz> nx = ny, in the case of an unbalanced biaxially stretched film: nz>nx> ny), the viewing angle dependence in the display device substrate is reduced, which is preferable.

-Third Aspect- In the third aspect, the photoisomerizable compound is a compound which causes stereoisomerization or structural isomerization by light. Many of these compounds, which are generally accompanied by a structural change and a change in color tone in the visible light range, are known as photochromic compounds. Specifically, specifically, azobenzene compounds, benzaldoxime compounds, and azomethine compounds. Compounds, stilbene compounds, spiropyran compounds, spirooxazine compounds, fulgide compounds, diarylethene compounds, cinnamic acid compounds, retinal compounds, hemithioindigo compounds and the like. These may be a low molecular weight compound or a polymer, and in the case of a polymer, the same function can be exhibited whether the photoisomerizable group is in the main chain or the side chain. The polymer is a homopolymer,
A copolymer may be used, and the copolymerization ratio of the copolymer is appropriately adjusted by appropriately adjusting polymer physical properties such as photoisomerization ability and Tg. Further, these photoisomerizable compounds may be the above-mentioned liquid crystal compounds at the same time. That is, a functional group capable of photoisomerization may be included in the molecule of the liquid crystal compound. For these, polymer, 41, (12), (1
992) p884, "Chromic Materials and Applications" (CMC Edition) p221, "Mechanochemistry" (Maruzen Edition) p21, "Polymer Papers Vol. 147, No. 10" (199)
1 year) p771 and the like.

As described above, the photoisomerizable compound causes stereoisomerization or structural isomerization by light,
An embodiment in which the reverse isomerization is caused by light / heat of another wavelength is preferable. For example, the azobenzene compound frequently repeats cis-trans isomerization by light irradiation and heat. For example, when the irradiation light is linearly polarized light, the azo group in an alignment state having an absorption axis in the vibration direction absorbs the irradiation light and repeats isomerization, but in the process, the vibration direction of the irradiation light happens to occur. On the other hand, an azo group oriented in the vertical direction or a direction close to the vertical direction can absorb light little or no and is immobilized. As a result, it is possible to easily vertically align the photoisomerizable compound by appropriately adjusting the irradiation light, and by increasing the value of the refractive index nz in the thickness direction of the optically anisotropic layer, The viewing angle dependence of the device substrate can be easily reduced.

The photoisomerizable compound is, for example, an alkyl group, an alkenyl group, an alkynyl group, an aryl group,
Heterocyclic group, cyano group, carboxyl group, carbamoyl group, alkoxycarbonyl group, aryloxycarbonyl group, acyl group, halogen atom, amino group, alkylamino group, arylamino group, acylamino group, alkylsulfonylamino group, arylsulfonyl group It has a substituent such as amino group, ureido group, alkoxy group, aryloxy group, acyloxy group, alkylsulfonyloxy group, arylsulfonyloxy group, alkylthio group, arylthio group, alkylsulfonyl group, arylsulfonyl group, sulfo group, and sulfamoyl group. You may have. These substituents are preferably arranged in the major axis direction of the photoisomerizable compound, but are not particularly limited.

Specific examples of the photoisomerizable compound (T
1 to T36), but the invention is not limited thereto.

[0101]

[Chemical 21]

[0102]

[Chemical formula 22]

[0103]

[Chemical formula 23]

[0104]

[Chemical formula 24]

[0105]

[Chemical 25]

[0106]

[Chemical formula 26]

As the light source of the linearly polarized light, the wavelength at which photoisomerization is exhibited varies depending on each photoisomerizable compound.
Suitable examples include a mercury lamp, a halogen lamp, and a xenon lamp, which have a wide wavelength range. Further, the irradiation linearly polarized light intensity (illuminance) has a great influence on the quantization yield by the photoisomerizable compound and the temperature in the optically anisotropic layer at the time of irradiation.
The visible light intensity is preferably 500 lux or more, more preferably 5000 lux or more, though it is preferably selected appropriately according to each characteristic.

The temperature for irradiating the linearly polarized light is set to the glass transition point (T
g) The vicinity, specifically, (Tg−30 ° C.) <(irradiation temperature) <(Tg + 50 ° C.) is preferable. When the temperature is in a temperature range extremely lower than the glass transition point (Tg) of the material forming the optically anisotropic layer, molecular motion is suppressed and photoisomerization is suppressed, so that birefringence is exhibited. On the other hand, in a temperature range considerably higher than the glass transition point (Tg), the contribution of relaxation due to the thermal motion of molecules becomes large, and birefringence may be difficult to develop.

Even if the photoisomerizable compound is already vertically aligned and fixed in the optically anisotropic layer, it undergoes further isomerization under the environment where light is irradiated, Optical properties may change over time. For the purpose of preventing such a phenomenon, a site that absorbs light, that is, a conjugated chain structure portion such as an azo group, an imino group, and a vinyl group is decomposed by oxidation, reduction, cleavage by reaction, or the like, or an optical abnormality is generated. It is possible to improve the durability of the optically anisotropic layer by chemically inactivating it by eluting it out of the anisotropic layer.

[Physical Properties of Display Device Substrate] In the display device substrate, the retardation of light incident on the display device substrate in the normal direction is Re [0] and is inclined by θ degrees from the normal direction. When the retardation of light incident at different angles is Re [θ], R at a wavelength of 550 nm
The value of e [0] / Re [θ] is preferably 0.93 to 1.07, more preferably 0.95 to 1.05, and 0.97 to 1.03. Is more preferable.
In the display device substrate, the value of Re [0] / Re [θ] at a wavelength of 550 nm is 0.93 to 1.0.
In the case of 7, a display device substrate having low viewing angle dependency and high visibility is provided.

[Structure of Display Device Substrate] The structure of the display device substrate is not particularly limited, and the optically anisotropic layer may be provided on one surface of the retardation plate surface. , May have on both surfaces.

[0112]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples.

(Example 1) -Production of retardation plate-Cycloolefin-based norbornene resin (manufactured by Zeon Corporation; "Zeonor 1420R") (resin having a positive intrinsic birefringence value) and styrene-maleic anhydride copolymerization Resin (manufactured by Nova Chemical Co .; "Dailark D332") (resin having a negative intrinsic birefringence value) was used. These resins were used after being dried under a nitrogen purge to reduce the water content. The absolute value of the retardation (Re) at a wavelength of 450 mm and a wavelength of 550 mm is Re
(450), Re (550), the cycloolefin-based norbornene resin (Re (450) / Re
The value of (550)) is 1.005, which is (Re (450) / Re of the styrene-maleic anhydride copolymer resin.
The value of (550)) is 1.069, the two values are not the same, and the difference is 0.064.

A coextrusion device 20 (manufactured by Toyo Seiki Co., Ltd .; "LABO PLASTOMILI", width of extrusion die 22 of 250 mm) having the structure shown in FIG. 1 was used. In this example,
The extruder 26 has two openings. Inside the extrusion die 22 (internal structure is shown in FIG. 4), the resin hopper extruded from the two openings of the extruder 26 is extruded from the extruder 24. It has a structure that joins from both sides of the resin hopper. Stretching roll 2 under the extrusion die 22
With 8, 30, and 32, the thickness of the film (laminate) 34 having a three-layer structure extruded from the extrusion die 22 is adjusted.

The styrene-maleic anhydride copolymer resin hopper is housed in the extruder 24, and the cycloolefin-based norbornene resin hopper is housed in the extruder 26. The norbornene resin / styrene-maleic anhydride copolymer resin / A melt-formed film (laminate) 34 having a three-layer structure made of norbornene resin was obtained. The thickness of the laminated body 34 is tried to be adjusted by controlling the peripheral speed of the tension rolls 28, 30, and 32, and the peripheral speed of the tension rolls 28, 30, and 32 is determined with the final thickness of 150 μm as a target.
A laminated body having a thickness of 8 μm was obtained. The obtained laminate was subjected to a stretching treatment of 58% in an atmosphere of 130 ° C.
A layered stretched film (retarder) was obtained. A schematic cross-sectional view of the obtained stretched film is shown in FIG. The obtained stretched film (retardation film) 50 had a structure in which a layer 54 made of a styrene-maleic anhydride copolymer was sandwiched between two layers 52, 52 'made of a norbornene resin. The thickness was norbornene resin layer 52 / styrene-maleic anhydride copolymer layer 54 / norbornene resin layer 52 ′ = 33 μm / 48 μm / 31 μm. The photoelasticity of the obtained retardation plate was 3.4 Brewster.

With respect to the obtained retardation plate 50, a retardation measuring device (manufactured by Oji Scientific Co., Ltd .; "KOBRA-21A") was used.
DH ") was used to measure the wavelength dispersion of retardation (Re). The results are shown in Table 1 and FIG.

[0117]

[Table 1]

As shown in Table 1 and FIG.
Is the retardation (Re) value at wavelengths of 450 nm, 550 nm and 650 nm, respectively.
0), Re (550) and Re (650),
It was found that Re (450) <Re (550) <Re (650) was satisfied, and that it had excellent characteristics of a 1/4 retardation plate in a wide band.

—Preparation of Substrate for Display Device— Using the photoisomerizable compound (Specific Example T2), the above retardation plate 5 was used.
An optically anisotropic layer was provided on the substrate 0 to prepare a display device substrate.

-Measurement of Refractive Index in Optically Anisotropic Layer- Refractive index in the in-plane slow axis direction (nx) and in-plane fast axis direction in the optically anisotropic layer of the display device substrate ( n
When y) and the refractive index (nz) in the thickness direction were obtained, the formula (nz ≧ (nx + ny) / 2) was satisfied.

-Measurement / Evaluation of Viewing Angle Dependence-The retardation of light (wavelength: 550 nm) incident in the normal direction to the obtained display device substrate and the angle inclined by 20 degrees from the normal direction. Light incident on (wavelength: 55
0 nm) retardation is measured, and Re [0] / R is measured.
The value of e [20] was 0.98, and it was found that the display device substrate of the present invention had low viewing angle dependence.

Comparative Example 1 A display device substrate was prepared in the same manner as in Example 1 except that the optically anisotropic layer was not provided in “Preparation of display device substrate” When the viewing angle dependency was measured and evaluated in the same manner as in Example 1, the value of Re [0] / Re [20] was 0.89.
It was found that the viewing angle dependence was high.

[0123]

According to the present invention, it is possible to provide a substrate for a display device which is excellent in visibility and has low viewing angle dependency.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a co-extrusion device suitably used for co-extrusion.

FIG. 2 is a diagram schematically showing the retardation plates manufactured in Example 1 and Comparative Example 1.

FIG. 3 is a diagram showing the results of measuring the wavelength dispersion of retardation (Re) with respect to the retardation plates manufactured in Example 1 and Comparative Example 1, using a retardation measuring device.

FIG. 4 is a schematic configuration diagram of a co-extrusion device suitably used for co-extrusion.

[Explanation of symbols]

20 Coextrusion equipment 22 Extrusion die 24 extruder 26 Extruder 28 tension roll 30 tension roll 32 tension roll 50 Phase plate 52 Layer composed of norbornene resin 52 'Layer made of norbornene resin 54 Layer consisting of styrene-maleic anhydride copolymer

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H049 BA06 BA07 BA25 BA42 BB03                       BB44 BB46 BB47 BB48 BB50                       BC03 BC05 BC09 BC22                 2H090 HB08X JB03 JB13 JD05                       KA05 LA06                 2H091 FA11X FA11Z FA41Z FC09                       FD06 HA07 KA02 LA16

Claims (7)

[Claims] 1. A wavelength of 450 nm, 550 nm and 65.
Retardation (Re) value at 0 nm is expressed as Re
When (450), Re (550), and Re (650), Re (450) <Re (550) <Re (65
0), and an optically anisotropic layer having a thickness of d, a refractive index in the in-plane slow axis direction of nx, a refractive index in the in-plane fast axis direction of ny, and a thickness direction of When the refractive index is nz, nz ≧ (nx + n
y) / 2, which is an optically anisotropic layer, and a substrate for a display device. 2. A mode in which the retardation plate contains a resin having a positive intrinsic birefringence value and a negative resin, and a mode including a laminate of a layer made of a resin having a positive intrinsic birefringence value and a layer made of a negative resin. The substrate for a display device according to claim 1, wherein the substrate is a copolymer composition having a chain having a positive intrinsic birefringence value and a chain having a negative chain, and a mode including a modified polycarbonate. 3. The display device substrate according to claim 1, wherein the optically anisotropic layer contains a liquid crystal compound aligned in the thickness direction of the optically anisotropic layer. 4. The optically anisotropic layer according to claim 1, which is at least one of a biaxially stretched film and an unbalanced biaxially stretched film made of a resin having a negative intrinsic birefringence value. Substrate for display device. 5. The substrate for a display device according to claim 1, wherein the optically anisotropic layer contains a photoisomerizable compound. 6. The retardation of light incident on the display device substrate in the normal direction is Re [0], and the retardation of light incident at an angle inclined by θ degrees from the normal direction is R.
Let e [θ] be Re at a wavelength of 550 nm.
The display device substrate according to claim 1, wherein the value of [0] / Re [θ] is 0.93 to 1.07. 7. The wavelength of the retardation plate is 450 nm and 550 n.
Retardation (Re) at m and 650 nm
The display device substrate according to claim 1, wherein a value of / wavelength (λ) is 0.2 to 0.3.