JP2002196143A - High molecular polarizing substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarized light separating plate which has high heat resistance and characteristics having no change with the lapse of time, efficiently utilizes incident illumination light and improves display brightness of a liquid crystal display element. SOLUTION: A high molecular polarizing substrate is a planar body, made of a transparent resin constituting a substrate of the liquid crystal display element and is distinguished such that when natural light is made incident perpendicularly on the planar body, respective diffraction efficiency of orthogonally crossed polarized light components of zero-th-order transmitted diffracted light is >=60% for one and <=40% for another.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polymer polarizing substrate. More specifically, the present invention relates to a polymer polarizable substrate having fine irregularities in the form of periodic linear ribs formed on the surface thereof and having a polarization separation function. INDUSTRIAL APPLICABILITY The substrate of the present invention can be used for a liquid crystal display panel, a liquid crystal projector, a liquid crystal rear projector, and the like because the substrate can efficiently use an incident illumination light beam and improve the display luminance of a liquid crystal display element.

[0002]

2. Description of the Related Art A polarizing film using iodine is widely used because of its high polarization separation ability, but has a drawback that iodine is easily sublimated. For this reason, it lacks durability against humidity, high temperature, and light, and cannot be used for various displays and automobile panels that are assumed to be used outdoors or under severe conditions. To compensate for these drawbacks, the entire film is subjected to a heat treatment to improve the water resistance or to highly polymerize (JP-A-6-118231), sandwiched between protective films such as cellulose acetate, polyester, and polycarbonate, Alternatively, there is a proposal to coat an acrylic resin. In addition, although a proposal has been made to use a dichroic dye having high resistance to heat, light, and humidity in place of iodine, in any case, the polarization characteristics are degraded with time due to decomposition, sublimation, and falling off of an adsorbed component. It was inevitable. Furthermore, an adhesive or the above-mentioned protective film for pasting on a glass substrate is indispensable, which means that an increase in the number of parts cannot be avoided. I was invited. Furthermore, in order to make the substrate thinner and lighter, glass of about 0.5 mm or 0.4 m
When the above-mentioned polyvinyl film is pasted on a plastic substrate of m or less, since the polyvinyl alcohol molecules are oriented by high stretching, stretching stress remains and causes the pasted substrate to be warped at high temperature or moisture absorption. .

[0003] In both cases using iodine and a dichroic dye, the principle of polarization separation is to obtain linearly polarized light by absorbing a polarized light component, so that the light transmittance of a single film may exceed 50%. could not. Since the energy of the absorbed light is converted into heat, a large amount of light needs to be transmitted to obtain a bright screen. Therefore,
Unnecessary use of electric energy such as brightening the backlight was inevitable. In particular, since a portable personal computer called a notebook personal computer or a mobile terminal is used with a battery power source, it is important to improve the light transmittance of the polarizing film. In order to improve the light use efficiency, a method has been proposed in which light from a light source is polarized through a circularly polarized light separating layer such as a cholesteric liquid crystal layer to realize a bright display (Japanese Patent Application Laid-Open Nos. 59-127017 and 59-27019). 61-122626,
JP-A-63-121821, JP-A-3-45906, JP-A-6-324333 and JP-A-7-35925. However, light incident perpendicularly to the circularly polarized light separating layer is transmitted as circularly polarized light in one direction to the left and right without color change, but light incident obliquely is transmitted as elliptically polarized light, causing a color change. Further, in order to prevent the above-mentioned color change, a method has been proposed in which elliptically polarized light that has been incident obliquely and has undergone color change has been transmitted through a retardation plate and a compensator to perform color compensation (Japanese Patent Laid-Open No. Hei 1 (1994)).
0-293211).

[0004]

However, in this method, a plurality of films such as a circularly polarizing plate, a retardation plate, and a compensating plate are indispensable, the system becomes complicated, the cost increases, the number of steps increases, the film thickness, There are many problems that must be solved, such as increase in weight and warpage at high temperatures due to differences in the coefficient of thermal expansion between the films. An object of the present invention is to provide a polarization separator having high heat resistance and characteristics that do not change with time, efficiently using an incident illumination light beam, and improving the display luminance of a liquid crystal display device.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above circumstances, and as a result, have prepared a glass substrate for liquid crystal display using a transparent resin, and formed a periodic linear rib type irregularity on the surface thereof. By attaching, without having to adsorb iodine or dichroic dye on the stretched sheet, we found that polarization separation was performed,
The present invention has been completed. This makes it possible to improve the heat resistance, water absorption, and deterioration over time, which were the drawbacks of the polyvinyl alcohol sheet. That is, the gist of the present invention is: A plate-like body made of a transparent resin constituting a substrate of a liquid crystal display element. When natural light is perpendicularly incident on the plate-like body, the respective diffraction efficiencies of polarization components of the zero-order transmitted diffraction light that are orthogonal to each other are different. 1. a polymer polarizing substrate, characterized in that one of them is 60% or more and the other is 40% or less. 2. A method for producing a polymer-polarizable substrate, wherein fine irregularities on the surface of the plate-like body are formed by casting. 4. The polymer polarizing substrate according to item 1, wherein the substrate is a liquid crystal display element. 4. The liquid crystal display device using the substrate according to item 4 or 3.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. (Polymer Polarizable Substrate) The polymer polarizable substrate of the present invention is a plate made of a transparent resin constituting the substrate of the liquid crystal display element, and when natural light is perpendicularly incident on the plate, it is zero. One of the diffraction efficiencies of the orthogonally polarized light components of the next transmitted diffracted light is 60% or more, and the other is 40% or less. Such a polymer polarizable substrate (hereinafter, referred to as
Polymer liquid crystal display substrate (LCD substrate)
Is not particularly limited, but in a preferred embodiment, fine unevenness having a polarization separation function is formed on one surface of the substrate, and the fine unevenness is a set of substantially parallel fine linear ribs. A body, preferably having the same cross-sectional shape, and preferably having ribs arranged at regular intervals. And the linear rib is
The pitch is 0.1-2 μm and the average opening width is 0.05-
Preferably, the thickness is 1.5 μm and the rib height is 0.5 to 10 times the average opening width.

Hereinafter, specific examples of the polymer polarizing substrate of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing a preferred embodiment of the present invention. On one surface of a polymer liquid crystal display substrate (hereinafter, referred to as LCD substrate) 101, fine irregularities 102 having a polarization separation function are formed. Generally, when dimensions such as the width and depth of fine irregularities are sufficiently large compared to the wavelength of incident light, catadioptric phenomena based on geometrical optics are observed, while these dimensions are comparable to the wavelength. In this case, a polarization characteristic due to a so-called structural birefringence phenomenon, which is explained by the vector diffraction theory, appears. In the present invention, an attempt is made to control the polarization separation function by making the structural constants such as the width and depth of the fine unevenness approximately equal to the wavelength of visible light. First, the polarization separation function of the fine unevenness 102 formed on the upper incident surface of the polymer polarizing substrate will be described with reference to FIG.

An ordinary light source is unpolarized natural light. This means that the intensity of the oscillating electric field component in a certain plane of the light and the intensity of the oscillating electric field component orthogonal thereto are statistically equal. When natural light is incident on the minute uneven portion 102 having the polarization separation function, a phenomenon occurs that they are transmitted or reflected according to a certain diffraction efficiency. Under appropriate diffraction conditions, it is possible to cause a certain difference in the diffraction efficiencies of the zero-order transmitted diffracted light of the electric field component (hereinafter P component) oscillating in the plane of incidence and the component orthogonal to it (hereinafter S component). Becomes
As a result, when the intensity of the zero-order transmitted diffracted light is observed, the P component is stronger than the S component, and under certain conditions, the intensity can be reversed. In this way, it becomes possible to express the polarization separation ability.

In FIG. 2, light is separately shown as a P component and an S component, and the P component represents a state when the S component is transmitted strongly and the S component is transmitted weakly. As shown in FIG. 2, the fine unevenness 102 is composed of substantially parallel ribs having a certain height, and when light is vertically incident on the surface having the fine unevenness, the light is perpendicular to the longitudinal direction of the rib. The electric field component (P component) that oscillates at the rib is diffracted by the rib, and the zero-order transmitted light travels inside the medium with large diffraction efficiency, but the electric field component (S component) that vibrates parallel to the longitudinal direction of the rib is As a result of the diffraction with the irregularities, the zero-order transmitted light has only a small diffraction efficiency, and a large difference occurs between the intensities of the oscillating electric fields of the transmitted zero-order light orthogonal to each other.

Therefore, the transmitted light becomes polarized light mainly composed of a component which vibrates in the direction perpendicular to the longitudinal direction of the rib forming the fine unevenness. The fine irregularities will be described in detail with reference to FIG. The form of the fine unevenness 102 is an aggregate of substantially parallel fine linear ribs. From the viewpoint of facilitating design and manufacture, it is preferable that the aggregate of the ribs has the same cross-sectional shape, and the ribs are preferably arranged at a constant period. Since the polarization separation function strongly depends on this spatial arrangement, here we show the preferred rib arrangement of the present invention,
Some vocabularies are defined as follows.

Rib 201: A peak portion of a rib. Groove 202: Space between adjacent ribs. Pitch 203: one cycle distance of the rib arranged on the base material surface. Opening width: The width of the groove in a plane parallel to the substrate surface. In a rectangular cross-sectional shape, the opening width is constant regardless of the depth. Maximum opening width 204: The maximum value of the opening width, usually the opening width at the upper end of the groove. Minimum opening width 205: The minimum value of the opening width, usually the opening width at the lower end of the groove. In a rectangular cross-sectional shape, 204 = 205. Rib height 206: the distance from the substrate surface to the top of the rib. Average opening width: A simple average value of the maximum opening width 204 and the minimum opening width 205. Aspect ratio: A value obtained by dividing the rib height 206 by the average opening width.

Hereinafter, a preferred rib arrangement will be described. The pitch 203 is preferably 0.1 to 2 μm,
１1 μm is more preferable. For convenience of rib production, it is preferable that the opening width is larger as it goes upward and smaller as it goes below.
The average opening width is preferably 0.05 to 1.5 μm, and 0.2
μm to 0.8 μm is more preferred. The aspect ratio is preferably from 0.5 to 10, preferably from 1.5 to 10, and more preferably from 2.5 to 10.

The optimization of these spatial arrangements is described in K. G
This was carried out with reference to the paper of Aylord et al. That is, an electromagnetic wave that passes through a diffraction region composed of fine irregularities is expressed as a superposition of spatial harmonic waves (this is referred to as Coupled).
Substituting into Maxwell equation)
The series of partial differential equations are described in a state variable expression, and the amplitudes of the incident area, the diffraction area, and the transmission area are determined by obtaining the amplitude of the spatial harmonic as a solution of the eigenvalue equation. In this treatment, diffraction efficiency is a function of structural factors such as rib height and width, the refractive index of the material forming the diffraction grating, and the wavelength of the incident light.

Graph 1 shows that the cross-sectional area of the linear ribs is rectangular, the pitch (203) is 0.5 μm, the average aperture width is 0.25 μm, and the refractive index is 1.64. This is a calculation of the diffraction efficiency of zero-order transmitted light when light of 5 μm is vertically incident. Rib depth (206)
Is about 0.91 μm, that is, the aspect ratio is 3.64.
In the case of (1), 90% of the component perpendicular to the longitudinal direction of the rib and 5% of the component parallel to the rib are transmitted, and it can be seen that a large polarization separation ability is exhibited. Graph 1 shows the aspect ratio of the linear rib, the diffraction efficiency of each polarized light, and the degree of polarization separation. Here, the aspect ratio is represented by Expression 1, and the degree of polarization separation is represented by Expression 4. The P component is a polarized light having a vibration plane perpendicular to the direction of the rib, and the S component is a polarized light having a vibration plane perpendicular to the rib.

[0015]

## EQU1 ## Aspect ratio = Rib depth (206) ÷ Average opening width

The polarization transmittance (T) was obtained by irradiating a linearly polarized light to a polymer polarizing substrate, measuring the transmission intensity thereof, and using the following equations (2) and (3). The degree of polarization separation (P) was determined according to the following equation 4 based on the calculated numerical values.

[0017]

## EQU2 ## T】 = (I‖ / I0)

[0018]

## EQU3 ## T⊥ = (I０ / I0)

[0019]

P (%) = ((T⊥−T‖) / (T⊥ + T)
‖)) * 100

I‖: Transmission intensity of a linearly polarized light component (S component) parallel to the direction of the parallel ribs I⊥: Linearly polarized light component (P component) perpendicular to the direction of the parallel ribs
I0: intensity of linearly polarized light without a polarizing substrate T‖: transmittance of polarized light (S component) parallel to the direction of parallel ribs T⊥: transmittance of polarized light (P component) perpendicular to the direction of parallel ribs

(Polymer Polarizing Substrate Resin and Method for Producing the Same) A polymer substrate for liquid crystal has high light transmittance, low birefringence suitable for liquid crystal display, high heat resistance, high mechanical strength.
Low water absorption and production yield are required. Although there is no particular limitation on the transparent resin that satisfies these requirements, preferred specific examples thereof include, for example, a polymer obtained by polymerizing a monomer selected from polyhydric acrylate, polyhydric methacrylate, monoacrylate, and monomethacrylate. An acrylic resin, a polycarbonate resin, an epoxy resin, or a cyclic polyolefin resin is exemplified. Among them, those which polymerize and cure by light irradiation to form a transparent polymer are preferably used because of their low birefringence. Although not particularly limited, a (meth) acrylate compound is generally suitable. Among them, triethylene glycol di (meth) acrylate, hexanediol di (meth) acrylate, 2,2-bis [4- (meth)
Acryloyloxyphenyl] propane, 2,2-bis [4- (2- (meth) acryloyloxyethoxy) phenylpropane, bis (oxymethyl) tricyclo [5.2.1.0 ^2,6 ] decane = dimethacrylate, p
-Bis [β- (meth) acryloyloxyethylthio]
Polyfunctional (meth) acrylates such as xylylene, 4,4'-bis [β- (meth) acryloyloxyethylthio] diphenyl sulfone, trimethylolpropane tri (meth) acrylate, urethane acrylate, epoxy acrylate, and monomers thereof Mixtures with monofunctional monomers copolymerizable with
A mixture of an acrylate compound and an addition-polymerizable polythiol is exemplified. As monofunctional monomers, for example, methyl (meth) acrylate, benzyl (meth) acrylate, and as polythiols, for example, pentaerythritol tetrakis (β-thiopropionate), tris [2- (β-thiopropionyloxy) ethyl] tri And isocyanurate. Although a monofunctional monomer or a polyfunctional monomer having a plurality of functional groups in a single molecule may be used, a polyfunctional monomer is preferably used. Among them, a bifunctional (meth) acrylate is preferably used.

In order to realize the above six properties in a well-balanced manner, a polymerizable composition containing the following components A or B:
Preferably, a resin obtained by polymerizing and curing the photocurable composition is suitably used. Component A: alicyclic skeleton bis (meth) acrylate represented by general formula (I) Component B: sulfur-containing (meth) acrylate represented by general formula (II)

[0023]

Embedded image

[Wherein, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, R ³ and R ⁴ each independently represent an alkylene group, and a represents 1 or 2. And b represents 0 or 1, p and q each independently represent 0 or 1. In formula (I), R ³ and R ⁴ when p = 1 and q = 1 are carbon Represents an alkylene group having the number of 1 to 4, preferably 1 or 2. Specific examples thereof include a methylene group and an ethylene group. And (R ³ ) _p and (R ⁴ ) _q
Are preferably p = 0 and q = 0, and p = 1 and q = 1 and R ³ and R ⁴ are methylene groups, and p = 1 and q = 1 and R ³ and R Those in which ⁴ is a methylene group are more preferred.

The alicyclic ring skeleton bis (meth) of the formula (I)
T) Specific examples of the acrylate compound include, for example, bis
(Hydroxymethyl) tricyclo [5.2.1.
0^2,6] Decane diacrylate, bis (hydroxymeth
Tyl) tricyclo [5.2.1.0^{2, 6}] Decane-Jime
Tacrylate, bis (hydroxymethyl) tricyclo
[5.2.1.0^2,6] Decane = acrylate methacrylate
And mixtures thereof, bis (hydroxymethyl)
Pentacyclo [6.5.1.1^3,6. 0^2,7. 0^9,13]
Nantadecane diacrylate, bis (hydroxymethyl
Le) pentacyclo [6.5.1.1^3,6. 0^2,7.
0^9,13] Pentadecane dimethacrylate, bis (hydr
Roxymethyl) pentacyclo [6.5.1.1^3,6. 0
^2,7. 0^9,13] Pentadecane acrylate methacrylate
And mixtures thereof.

Among these, bis (hydroxymethyl) to
Licyclo [5.2.1.0^2,6] Decane-diak relay
G, bis (hydroxymethyl) tricyclo [5.2.
1.0 ^2,6Decane dimethacrylate is preferred. This
These tricyclodecane compounds and pentacyclodecane
Compounds may be used in combination within a group and / or between groups.
Good.

[0027]

Embedded image

[Wherein, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 1 to 6 carbon atoms, and Ar may be substituted with a halogen atom having 6 to 30 carbon atoms. X represents an arylene group or an aralkylene group, and X represents -O-
Or -S-, and Y is -S- when X is -O-.
Or -SO ₂ - represents, when X is -S- -S-,
—SO ₂ —, —CO— or an alkylene group or an aralkylene group having 1 to 12 carbon atoms, which may have an ether oxygen atom or a thioether sulfur atom, and m and n
Represents an integer of 1 to 5, and p represents an integer of 0 to 10.]

In the formula (II), R ² has 1 to 6 carbon atoms;
It preferably represents 1 to 3 alkylene groups, and specific examples thereof include a methylene group, an ethylene group, and a triethylene group. Ar represents an arylene group or an aralkylene group having 6 to 30 carbon atoms, preferably 6 to 12 carbon atoms, which may be substituted with a halogen atom, and specific examples thereof include a phenylene group. X being an alkylene group or an aralkylene group having an ether type oxygen atom or a thioether type sulfur atom means that it is an alkylene ether group, an aralkylene ether group, an alkylene thioether group or an aralkylene thioether group.

Specific examples of the sulfur-containing (meth) acrylate compound of the formula (II) include, for example, p-bis (β- (meth) acryloyloxyethylthio) xylene and m-bis (β- (meth) acryloyl). Oxyethylthio) xylene, α, α′-bis (β- (meth) acryloyloxyethylthio) -2,3,5,6-tetrachloro-p-xylene, 4,4′-di (β- (meta ) Acryloyloxyethoxy) diphenyl sulfide, 4,
4'-di (β- (meth) acryloyloxyethoxy)
Diphenyl sulfone, 4,4'-di (β- (meth) acryloyloxyethylthio) diphenyl sulfide,
4,4'-di (β- (meth) acryloyloxyethylthio) diphenylsulfone, 4,4'-di (β- (meth) acryloyloxyethylthio) diphenylketone, 2,4'-di (β- ( (Meth) acryloyloxyethylthio) diphenyl ketone, 4,4′-di (β- (meth) acryloyloxyethylthio) -3,3 ′, 5
5′-tetrabromodiphenyl ketone, β, β′-bis (p- (meth) acryloyloxyphenylthio) diethyl ether, β, β′-bis (p- (meth) acryloyloxyphenylthio) diethylthioether and the like. Can be

Among them, 4,4'-bis (β-methacryloyloxyethylthio) diphenyl sulfone has a high refractive index and is preferably used. Various refractive indices can be used for the polymer polarizable substrate obtained by polymerizing these monomers, if necessary. However, the resin having a refractive index of 1.34 to 1.71 is L
It is preferably used in applications of a polymer polarizing substrate for a CD substrate. Above all, those having a refractive index of 1.5 or more can greatly increase the difference in diffraction efficiency between polarization components orthogonal to each other, and are very preferable.

The polymerizable composition containing the component A or B in the present invention is shaped and cured. The curing is performed by a known radical polymerization in which a photopolymerization initiator that generates a radical by an active energy ray such as ultraviolet light is added. 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-
And trimethylbenzoyldiphenylphosphine oxide. Preferred photoinitiators include 2,4,6
-Trimethylbenzoyldiphenylphosphine oxide M, benzophenone.

Two or more photopolymerization initiators may be used in combination. The addition amount of these photopolymerization initiators 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. If necessary, an antioxidant, an ultraviolet absorber, a coloring agent, and the like can be added to the photocurable liquid monomer to cure the monomer.

Various additives may be added without departing from the spirit of the present invention. For example, a release agent such as silicone oil may be used to facilitate release from the mold. Examples of the method for forming the polymer polarizing substrate 101 include injection molding, extrusion molding, solvent casting, and molding and curing molding in which heat or light is applied to a mold and then cured by heat or light. In the injection molding, a transfer method using a precision stamper for producing and transferring fine irregularities inside a mold can be used. Also,
A transfer method using a precision stamper that presses and transfers a mold having fine irregularities after forming into a sheet by extrusion molding can be used. In the case of a solvent cast or a mold-curable mold, a transfer method in which a polymer solution or a monomer is injected into a mold having fine irregularities, cured, and then transferred can be used. Any of these can be used, but in order to satisfy various characteristics of the liquid crystal substrate, shape curing molding by photopolymerization is suitably used. Hereinafter, the shaping and curing molding will be described in detail, but is not limited to this method.

The amount of the active energy rays 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. If it is not sufficiently expressed and conversely, if it is excessively excessive, deterioration of the cured product due to light, such as yellowing, will occur.
Ultraviolet rays of 00 to 400 nm are preferably 0.1 to 200 nm.
Irradiate in the range of J. 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 heated in the range of 30 to 300 ° C. simultaneously or sequentially 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 peroxycarbonate, t-butylperoxy (2-ethylhexanoate), and the amount of the monomer used is 10
It is preferably 1 part by weight or less based on 0 part by weight.

Further, in the present invention, the completion of the polymerization reaction and the internal strain generated during the polymerization can be reduced by heating the cured product after performing the radical polymerization by light irradiation. The heating temperature is appropriately selected according to the composition of the cured product and the glass transition temperature. However, since excessive heating causes deterioration in the hue of the cured product, a temperature near or below the glass transition temperature is desirable.

(Liquid Crystal Cell) A liquid crystal cell using the polymer polarizing substrate will be described. In FIG. 4, the light guide 104
The natural light emitted from the linear light source 105 disposed at the side end of the light guide enters from the side end and travels to the side while being totally reflected in the light guide, but the light reflected at the lower surface of the light guide rises upward and The light reaches the fine uneven surface 102 of the molecular polarizing substrate 101. Part of the light (P component polarized light) that has reached the fine irregularities 102 is transmitted through the upper liquid crystal surface and emitted.
Is reflected downward. Both are partially polarized light having the plane of maximum intensity polarization as described above. The partially polarized light (mainly S component polarized light) reflected downward is reflected by the reflector 103 and travels upward again.

The polarization plane rotation behavior of the reflected light depends on the composition and shape of the reflection plane. For example, a reflection plate 10 having a silver vapor deposition surface
In the case of 3, the polarization plane rotates by a certain angle,
When 03 is made of expanded polyethylene terephthalate, it rotates almost completely at random. Therefore, fine irregularities 1
When the light reflected at 02 is reflected by the reflector 103 and reaches the fine unevenness 102 again, it is natural light or partial polarized light whose maximum intensity polarization plane has changed.

Therefore, since this light has an increased P-polarization plane component transmitted through the fine irregularities 102, it is guided to the liquid crystal element and contributes to an increase in the amount of light for effective illumination. When the reflection at the fine irregularities 102 is repeated infinitely, the light amount utilization rate converges to a certain value. This is due to the loss of incident light on the lower surface of the light guide plate 104, and is about 75%. The polarized light having passed through the polymer polarizing substrate 101 passes through the liquid crystal layer 106 and the substrate 107 and reaches the polarizing plate 108. The material of the substrate 107 may be glass, but a flat substrate made of the same polymer as that used in 101 for light weight and thinness may be used. The polarizing plate 108 does not use the product of the present invention. In the present invention, since the polarized light is separated by reflection, when the reflected light returns to the liquid crystal layer again, bleeding or disturbance of display may occur. Therefore, it is necessary to use a normal absorption type polarizing plate as the polarizing plate 108. Further, an absorption type polarizing plate may be inserted between the polymer polarizing substrate 101 and the backlight 104 for the purpose of improving the polarization separation ability. In this case, a polarizing plate to be inserted has a high transmittance, but a polarizing plate having a low polarization separation ability is sufficient.

[0041]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the present invention. The water absorption was measured by the weight change after immersion in water at 23 ° C. for 24 hours according to JIS K6911. The glass transition temperature was measured according to JIS K7121. The high temperature and high humidity test was conducted by placing the polymer polarizing substrate at 60 ° C and 95% environment.
After leaving for 00 hours, the mixture is allowed to cool to room temperature, then linearly polarized light is incident, transmitted light is detected, and the polarization transmittance is calculated using Equations 2 and 3. Also, the degree of polarization separation is calculated using Equation 4. The maximum polarization transmittance is the highest value among the polarization transmittances. In the heat resistance test, the polymer polarizable substrate was heated in an oven at 120 ° C. for 200 hours, allowed to cool to room temperature, then linearly polarized light was incident, transmitted light was detected, and the polarization transmittance was calculated using Equations 2 and 3. Ask. Also, the degree of polarization separation is calculated using Equation 4.

Example 1 Bis (hydroxymethyl) tricyclo [5.2.1.0
^2,6 ] decane = 100 parts of dimethacrylate, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (“Lucillin TPO” manufactured by BASF) as a photoinitiator
After uniformly stirring and mixing 0.05 parts and 0.05 parts of benzophenone, the composition was defoamed to obtain a composition. The nickel fine irregularity stamper was manufactured by transferring from a glass substrate master made by photolithography by electroforming. Its shape is
A pattern in which grooves having a pitch of 0.5 μm and an average opening width of 0.25 μm were arranged in parallel was formed on the entire surface of the stamper, and the groove depth was set to 0.9 μm.

This composition was used as a set of an optically polished glass and a nickel stamper having fine irregularities formed on the surface, and a 0.4 mm thick gap was formed using a 0.4 mm thick silicon plate as a spacer. The mixture was poured into a mold and irradiated with ultraviolet rays for 5 minutes between metal halide lamps having an output of 80 W / cm, which were above and below the glass surface at a distance of 40 cm.
After the irradiation with ultraviolet rays, the mold was removed and heated at 160 ° C. for 1 hour to obtain a cured product. As a result of the transfer, the polymer polarizable substrate has ribs formed on the surface, and has a pitch of 0.5 μm and an average opening width of 0.1 μm.
25 μm and a groove depth of 0.9 μm were confirmed.

The refractive index of the obtained polymer polarizing substrate was 1.
52. In order to evaluate the polarization separation function, linearly polarized light having a wavelength intensity peak of 0.5 μm was incident parallel or perpendicular to the rib from the side with the unevenness, and the polarization separation characteristics of the straight-ahead emitted light were measured. As a result, the S-polarized light component of the emitted light parallel to the rib was 18%, and the P-polarized light component perpendicular to the rib was 92%. Therefore, the polarization separation degree was 67%. When a high-temperature and high-humidity test was performed on the obtained polymer polarizing substrate, there was no change in the polarizing characteristics. When a heat resistance test was performed, there was no change in polarization characteristics. Table 1 shows the results. That is, the polarizing plate has no change in physical properties at high temperature and high humidity.

Example 2 In Example 1, bis (hydroxymethyl) trisic
B [5.2.1.0^{2, 6}] Of decane dimethacrylate
Instead of 4,4'-bis (β-methacryloyloxy
Except that tylthio) diphenylsulfone was used.
Inject into the mold according to the method described in Example 1
Compound was obtained. The refractive index of the obtained cured product was 1.64.
Was. The degree of polarization separation was measured in the same manner as in Example 1. The result
As a result, when natural light is incident, the S-polarized light component of the emitted light is 5.
2% and the P-polarized component were 90%. Therefore, polarization separation
The degree was 89%. Heat measurement by the method described in Example 1,
And high-temperature characteristics, before heating test and high-humidity test
Later, the degree of polarization separation did not change. The results are shown in Table 1.
As in the case of Example 1, there is no partial change in physical properties at high temperature and high humidity.
It is a light plate.

Comparative Example 1 For comparison, a polarizing film (TEC) prepared by dyeing polyvinyl alcohol partially dehydrated polyvinyl alcohol with iodine ink and sandwiching it with cellulose acetobutyrate was used.
0.4 mm thick polymer prepared in the same manner as in Example 1 except that a mold in which H SPEC (manufactured by Polaroid) is assembled using optically polished glass on both sides instead of a nickel plate having fine irregularities is used. A polymer substrate with a polarizing function was formed by bonding to a substrate. Table 1 shows the polarization separation, the maximum polarization transmittance, and the glass transition temperature. 99% polarization separation
However, when a heat resistance test was performed on the obtained polymer polarizing substrate, light having a wavelength of 0.4 μm to 0.59 μm was not transmitted at all. Therefore, the degree of polarization separation is 0.
Met.

When a high-temperature and high-humidity test was performed on the obtained polymer polarizing substrate, the transmittance was reduced from 68% to 61%, and the degree of polarization separation was reduced from 99% to 89%. This is presumably because the polyvinyl iodide having a high water absorption rate is used for the base material, and the orientation of iodine is reduced by water absorption. Table 1 shows the results. That is, it cannot be used at all at high temperatures, and the transmittance and the degree of polarization separation decrease even at high humidity.

[0048]

[Table 1]

[0049]

As described above, the present invention has high heat resistance and characteristics that do not deteriorate with time, efficiently utilizes incident illumination rays, and is used to improve the polarization separation used for improving the display brightness of a liquid crystal display device. The purpose of the present invention is to provide a means for realizing the plate as a single liquid crystal display substrate. If the polymer polarizing substrate of the present invention is used for a liquid crystal display cell, the weight and thickness of the display element can be reduced.
Further, the yield can be improved by facilitating the assembly process of the liquid crystal display cell.

[Brief description of the drawings]

FIG. 1 is a side view and a partially enlarged perspective view of an example of a polymer polarizing substrate of the present invention.

FIG. 2 is a conceptual diagram illustrating the polarization separation function of the polymer polarizing substrate of the present invention.

FIG. 3 is an explanatory view of a fine concavo-convex pattern of the polymer polarizing substrate of the present invention.

FIG. 4 is an explanatory view of a usage example of the polymer polarizing substrate of the present invention.

FIG. 5 is a graph illustrating zero-order diffraction efficiency of a P component and an S component of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Polymer polarizing substrate 102 Fine unevenness 103 Reflector 104 Backlight 105 Linear light source 106 Liquid crystal layer 107 Substrate 108 Polarizer 201 Rib 202 Groove 203 Pitch 204 Maximum opening width 205 Minimum opening width 206 Rib height

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // B29K 33:04 B29K 33:04 105: 32 105: 32 B29L 11:00 B29L 11:00 (72) Inventor Seiichiro Hayakawa 8-3-1 Chuo, Ami-cho, Inashiki-gun, Ibaraki Pref. F-term in the Tsukuba Research Laboratory, Mitsubishi Chemical Corporation (reference) FB02 FC07 LA04 4F204 AA21 AA44 AG01 AG05 AH73 EA03 EB01 EB29 EF01

Claims (11)

[Claims] 1. A plate-like body made of a transparent resin constituting a substrate of a liquid crystal display element, wherein, when natural light is perpendicularly incident on the plate-like body, with respect to polarization components orthogonal to each other of zero-order transmitted diffraction light, A polymer polarizable substrate, wherein one of the diffraction efficiencies is 60% or more and the other is 40% or less. 2. The polymer polarizable substrate according to claim 1, wherein an aggregate of substantially parallel fine linear ribs having fine irregularities is formed on one surface of the plate-like body. 3. The linear rib has a pitch of 0.1 to 2 μm,
The polymer polarizable substrate according to claim 2, wherein the average opening width is 0.05 to 1.5 m and the rib height is 0.5 to 10 times the average opening width. 4. The transparent resin has a refractive index of 1.34 to 1.71.
The polymer polarizing substrate according to any one of claims 1 to 3, wherein 5. The polymer polarizing substrate according to claim 1, wherein the glass transition temperature of the transparent resin is 100 ° C. or higher. 6. The polymer polarizing substrate according to claim 1, wherein the transparent resin has a water absorption of 1% by weight or less. 7. The polymer polarizable substrate according to claim 1, wherein the transparent resin is obtained by polymerizing and curing a polymerizable composition containing the following components A or B. Component A: alicyclic skeleton bis (meth) acrylate represented by general formula (I) Component B: sulfur-containing (meth) acrylate represented by general formula (II) [Wherein, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and R ³ and R ⁴ each independently represent
Represents an alkylene group, a represents 1 or 2, b represents 0 or 1, p and q each independently represents 0 or 1.] [Wherein, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group having 1 to 6 carbon atoms, and Ar has 6 to 30 carbon atoms.
Represents an arylene group or an aralkylene group optionally substituted with a halogen atom, X represents -O- or -S-, and Y represents -S- or -SO ₂ -when X is -O-.
-S When the stands, X is _{-S- -, - SO 2 -,} -
CO- or an alkylene group or an aralkylene group which may have an ether type oxygen atom or a thioether type sulfur atom having 1 to 12 carbon atoms, m and n each represent an integer of 1 to 5, and p represents 0 to 0. Represents an integer of 10] 8. The polymerizable polarizing substrate according to claim 7, wherein the polymerizable composition is a photocurable composition. 9. A method for producing a polymer-polarizable substrate, wherein fine irregularities on the surface of a plate-like body are formed by casting. 10. The substrate according to claim 1, wherein the substrate is for a liquid crystal display device.
9. The polymer-polarizable substrate according to any one of items 8 to 8. 11. A liquid crystal display device using the substrate according to any one of claims 1 to 8 and 10.