CN1381754A - Optical device and liquid crystal display unit - Google Patents

Optical device and liquid crystal display unit Download PDF

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Publication number
CN1381754A
CN1381754A CN02104625A CN02104625A CN1381754A CN 1381754 A CN1381754 A CN 1381754A CN 02104625 A CN02104625 A CN 02104625A CN 02104625 A CN02104625 A CN 02104625A CN 1381754 A CN1381754 A CN 1381754A
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China
Prior art keywords
optical device
tack coat
liquid crystal
refractive index
polarizer
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CN02104625A
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Chinese (zh)
Inventor
宫武稔
矢野周治
西小路祐一
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Nitto Denko Corp
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Nitto Denko Corp
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Publication of CN1381754A publication Critical patent/CN1381754A/en
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    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
    • B32B2457/202—LCD, i.e. liquid crystal displays
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers
    • G02F1/133541—Circular polarisers
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133638—Waveplates, i.e. plates with a retardation value of lambda/n
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2202/00—Materials and properties
    • G02F2202/28—Adhesive materials or arrangements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F2413/00—Indexing scheme related to G02F1/13363, i.e. to birefringent elements, e.g. for optical compensation, characterised by the number, position, orientation or value of the compensation plates
    • G02F2413/02—Number of plates being 2

Abstract

An optical member has a polarizer, a viewing angle compensating plate, and an adhesive layer which has a refractive index ND20 not lower than 1.485 and through which the polarizer and the viewing angle compensating plate are laminated on each other. A liquid-crystal display device has at least one optical member defined above, a liquid-crystal cell, and an adhesive layer which has a refractive index ND20 not lower than 1.485 and through which the optical member is bonded onto at least one of opposite surfaces of the liquid-crystal cell.

Description

A kind of optical device and liquid crystal indicator
The present invention is based on Japan special permission communique No.2001-116431, this communique is used for referencial use in the present invention.
Technical field
The present invention relates to a kind of optical device that can be used to form liquid crystal indicator, the visuality of this liquid crystal indicator, for example contrast under the broad visual angle and brightness are all very good.
Background technology
Up to now, in large screen television that adopts liquid crystal display or similar device, need 80 contrasts of spending in the angulars field of view on vertical and horizontal direction be 10 or higher.Consider this requirement, in Proceedings of SID2000[31,35.3 (2000) 902] in proposed a kind of based on subregion (split portions) thus be that each pixel is divided into the problem that a plurality of territories obtain rather than the brightness adopting the single domain type to adopt the method for circuit polarizer to solve to reduce to cause owing to numerical aperture reduces in liquid crystal panel.Perpendicular alignmnet (VA) pattern as multiple domain in liquid crystal panel is divided into little territory with liquid crystal aligning, is used for compensating the optical path difference (retardation) of each territory and another territory (pixel) generation, thereby reaches good visuality in the visual angle of broad.Yet, when showing black, the problem that the contrast that can occur being caused by the leakage of light reduces.
Summary of the invention
An object of the present invention is to develop a kind of optical device, it can prevent to divide the problem that the contrast in the display packing reduces based on the pixel of circular polarisation mode by adopting circuit polarizer, thereby can form a kind of liquid crystal indicator, its visuality for example contrast under the broad visual angle and brightness is all very good.
According to the invention provides a kind of optical device, it comprises: circuit polarizer; The viewing angle compensation plate; Refractive index N D 20Be not less than 1.485 tack coat, circuit polarizer and viewing angle compensation plate are stacked together mutually by this tack coat.According to the invention provides a kind of liquid crystal indicator, comprise at least one above-mentioned optical device, a liquid crystal cell, and a refractive index N D 20Be not less than 1.485 tack coat, optical device is bonded at least one facing surfaces of liquid crystal cell by this tack coat.
Can obtain a kind of optical device according to the present invention, when it is applied to pixel division display packing with circuit polarizer, can prevent because the problem that the contrast that circular polarisation mode causes reduces, thereby can form a kind of liquid crystal indicator, its visuality for example contrast under the broad visual angle or brightness is all very good.This is that boundary reflection owing to optical device is suppressed and realizes.In other words, the inventor has overcome in pixel and has divided in the display packing because the problem that the contrast that circular polarisation mode causes reduces by research.Found that the following fact.For this reduction of contrast, be when circularly polarized light reflex time on the interface, the variation of 180 degree takes place in phase place, makes sense of rotation laterally anti-phase.Like this, a part is converted into unexpected circularly polarized light at the circularly polarized light of display panels boundary reflection.As a result, this unexpected circularly polarized light has just become leak light when showing black, makes contrast reduce.
Therefore, a kind of can the inhibition because the anti-phase optical device of circularly polarized light that boundary reflection causes proposed, overcome pixel divide in the display packing by cause based on the circular polarisation mode of multiple domain orientation the problem that reduces of contrast, show thereby in the visual angle of broad, reach good contrast.In addition, in the liquid crystal display at broad visual angle, can come picture with the aid of pictures from the narrower angle that has relatively than the display screen of decline angle of squint, boundary reflection is also more remarkable.Therefore, suppress boundary reflection and have significant role improving visuality.
Description of drawings
From hereinafter and in conjunction with the accompanying drawings, can know feature of the present invention and advantage to the introduction of preferred embodiment.
Fig. 1 is the cut-open view of embodiments of the invention.
Embodiment
Comprise according to the invention provides a kind of optical device: circuit polarizer; The viewing angle compensation plate; Refractive index N D 20Be not less than 1.485 tack coat, circuit polarizer and viewing angle compensation plate stack mutually by this tack coat.Fig. 1 has shown an example of this optical device.In Fig. 1, label 1 expression circuit polarizer; Label 2 expression refractive index N D 20Be not less than 1.485 tack coat; Label 3 expression viewing angle compensation plates.Also have, circuit polarizer 1 shown in Figure 1 passes through refractive index N by linear polarizer 11 and quarter-wave plate 13 D 20Being not less than 1.485 tack coat 12 is stacked together and makes.In Fig. 1, label 4 is also represented refractive index N D 20Be not less than 1.485 tack coat.Tack coat 4 is used for a device and another device bonding, and is temporarily covered by as shown in Figure 1 spacer 5 usually, so tack coat 4 is protected, drops into actual use up to it.
Can select suitable material to come, to its kind and without particular limitation as circuit polarizer.The example of circuit polarizer comprises the circuit polarizer of being made by the lamination of as shown in Figure 1 linear polarizer and quarter-wave plate, and the circuit polarizer of being made by the cholesteric that is orientated on the Grandjean structure.
Can adopt the suitable material that to propagate linearly polarized photon but absorb other light to be used as linear polarizer, to its kind and without particular limitation.Preferably can adopt polaroid, or the polaroid that one or two surface is all protected by protective clear layer is as linear polarizer.An example of polaroid is the water absorbent polymer film that stretches, for example polyvinyl alcohol film, the formalized polyvinyl alcohol film of part, and perhaps partly-hydrolysed ethylene vinyl acetate polymer film wherein contains the iodine and/or the dichroic dye of absorption.
As required, the protective clear layer on of polaroid or each apparent surface can be made by suitable polymkeric substance.Particularly, protective clear layer is preferably made by the polymkeric substance with excellent transparency, physical strength, thermal stability and moisture resistance.Protective clear layer can be formed by suitable method, as the method for coat polymers solution, and the method for bonding or laminated film.
The specific examples of polymkeric substance comprises: cellulosic polymer, for example cellulose diacetate or cellulose triacetate; Polyester polymers, for example polyethylene terephthalate or polyethylene glycol phthalate; Acrylic polymers, for example carbonate polymer or polymethylmethacrylate; Styrene polymer, for example polystyrene or acrylonitrile-styrene polymkeric substance; Olefin polymer, for example tygon, polypropylene, polyolefin, or ethylene-propylene copolymer with ring texture or norborene structure; And amide polymer, for example nylon or aromatic poly amide.
The example of polymkeric substance also comprises: diimide polymkeric substance, sulfone polymer; Polyether sulfone polymer; Polyetheretherketonepolymer polymer; The polyphenylene sulfide polymkeric substance; Vinyl alcohol polymer; The allylation polymkeric substance; Polymethanal polymer; Epoxy polymer; Ethene butyral polymkeric substance; These mixture of polymers; And polymkeric substance polyester polymers for example, acrylic polymers, urethane ester polymer, amide polymer, siloxane polymer, or the epoxy polymer that solidifies by heating or ultraviolet ray irradiation.Especially, polymkeric substance preferably can adopt has good isotropic material, as the mean refractive index N of ordinary grade D 20It is 1.48 cellulose triacetate.
Can make the quarter-wave plate that linearly polarized light is converted to circularly polarized light with suitable material.This examples of material comprises: the birefringent film of being made up of the oriented film of the polymkeric substance of any kind of; The oriented film of liquid crystal polymer, for example discotic type liquid crystal polymer or nematic crystal polymkeric substance; With the transparent substrates that has supported this aligned liquid-crystal layer.Material listed in the introduction of above-mentioned protective clear layer can be suitable for the form dielectric grid film.Oriented film can be the film after handling through proper method, for example uniaxial tension method or biaxial stretch-formed method.Quarter-wave plate can be a birefringent film, and it has by the refractive index on the thickness direction of proper method control, for example applies the method for convergent force, or/and the means of heat-shrinkable film with the birefringent film bonding is applied the method for bulging force.
Quarter-wave plate can be the lamination of two layers or multilayer optical path difference layer, with control optical property such as optical path difference.Also have, can adopt so a kind of method, will be as the optical path difference layer of the quarter-wave plate of the light of monochromatic light such as 550nm wavelength and optical path difference layer with other optical path difference performance, for example the optical path difference layer as 1/2nd wave plates is stacked together mutually.In the case, the gained wave plate can use as quarter-wave plate in the wavelength coverage of broad such as visible-range.
A kind of suitable material has when natural light is incident on the material it can reflect left-hand and an intrafascicular light beam of dextrad circularly polarized light but the performance of propagating another light beam.This material can be as the circuit polarizer of being made up of the cholesteric that is orientated on the Grandjean structure, to its kind and without particular limitation.Cholesteric can have a kind of structural arrangements, the different layer of pitch two-layer, three layers or multilayer Grandjean structural approach that wherein bondd, and promptly the layer that Fan She optical wavelength is different combines, and these layers are stacked mutually.Stack by this that can obtain can be at the circuit polarizer of broad wavelength coverage such as visible-range internal reflection circularly polarized light ability.Therefore, can obtain the circularly polarized light in the broad wavelength coverage, propagated.
The circuit polarizer of being made up of cholesteric can obtain by liquid crystalline polymer film.As a rule, can obtain circuit polarizer by the transparent substrates with liquid crystalline polymer layer, wherein liquid crystalline polymer layer is formed on the transparent substrates, can be orientated on the Grandjean structure by friction by the film of orientation.The cholesteric that stacks can form by the method for coating again.Also have, any suitable polymkeric substance listed in the introduction of protective clear layer can be used as transparent substrates.
The viewing angle compensation plate can be used in the introduction of quarter-wave plate listed any and have a suitable plate that the material of suitable optical path difference is made when using together with liquid crystal cell.From the viewpoint of compensating effect, preferably the front lighting path difference is not more than 100nm to the viewing angle compensation plate for wavelength is the light of 550nm, the thickness optical path difference is not less than 50nm.Also have, the front lighting path difference is (nx-ny) d, the thickness optical path difference be (nx+ny)/2-nz}d, nx wherein, ny is the refractive index in the plane, nz is the refractive index on the thickness, d is the thickness of viewing angle compensation plate.
Circuit polarizer and viewing angle compensation plate are by refractive index N D 20Be not less than 1.485 tack coat and be stacked together mutually, therefore can suppress boundary reflection.Particularly, consider through the protective clear layer of cellulose triacetate commonly used as linear polarizer, the refractive index N of so used tack coat D 20Preferably be not less than 1.485, but be between the refractive index of these two kinds of materials less than the refractive index of refractive index, the especially tack coat of viewing angle compensation plate and quarter-wave plate.
Here, N D 20Being meant under 20 ℃ temperature, is the measured refractive index of D spectral line (598.3nm) in the sodium spectral line to wavelength.
Therefore, when linear polarizer and quarter-wave plate are stacked together when forming circuit polarizer mutually, perhaps when two-layer or multilayer optical path difference layer were stacked together the formation circuit polarizer mutually, lamination preferably formed by the tack coat with above-mentioned refractive index.Also have, be used to form the mean refractive index N of tack coat of the common employing of viewing angle compensation plate or quarter-wave plate D 20, when adopting polycarbonate, be 1.585, when adopting the poly-allylat thing, be 1.603, when adopting polysulfones is 1.633, when adopting norbornene resin is 1.513, is 1.650 when adopting liquid crystal polymer, is 1.570 when adopting the polymerisable liquid crystal of ordinary grade.
From the viewpoint of quality stability, owing to need prevent the skew of optic axis and the efficient that improves the assembling liquid crystal indicator, the material that therefore forms optical device preferably is stacked together by tack coat or forms.Tack coat is preferably made by the suitable adhesive that can satisfy above-mentioned refractive index requirement, and there is no particular restriction to its kind.Also have, the example of bonding agent comprises resinoid, energy beam cure adhesive, hot-melt adhesive, bi-component hybrid reaction type bonding agent, and tacky adhesion.Adopt preferably that light transmission good bonding agent, especially light transmission is not less than 80% bonding agent in visible-range (380nm is to 720nm), more especially light transmission is not less than 90% bonding agent.From preventing the viewpoint of variable color, bonding agent does not preferably have absorbability with respect to the light of a certain specific wavelength.
From the simple viewpoint that bonds, at room temperature also has viscoelastic bonding agent even preferably adopt.Tackifier as forming tack coat can adopt to have the material of suitable polymers as matrix polymer, and these suitable polymers have acrylic polymers, siloxane polymer, polyester polymers, polyurethane polymkeric substance, polyether polymer, or rubber polymer.For the optical property that prevents material descends, preferably adopting neither needs hot setting processing and high temperature drying to handle, and does not also need the long-time material of handling with long-time dried that solidifies.In addition, preferably adopt the heating and wet condition under do not have segregation problem such as material floating or that come off.
From the viewpoint of tack coat, the material of employing preferably its glass transition temperature is not higher than 20 ℃.For example, tack coat can be the acrylic acid tackifier that are prepared as follows.To comprise and have 20 or the alkyl of carbon atom still less, as methyl, ethyl or butyl, (methyl) acrylate, with combine as the acrylic monomers copolymerization that (methyl) acrylic acid or (methyl) acrylic acid-hydroxyethyl acid is formed by altered contents, obtain the tack coat that glass transition temperature is not higher than 20 ℃.Therefore, just form counterpoise molecular weight and be not less than 100000 acrylate copolymer.Acrylate copolymer is prepared the acrylic acid tackifier as matrix polymer.The acrylic acid tackifier also have good transparency, moisture resistance and stable on heating advantage.
Also have, the acrylate copolymer that is formed by monomer has about 1.47 refractive index usually.Therefore, can improve refractive index by suitable method, the method that obtains acrylate copolymer of monomer such as the styrene by the copolymerization phenyl for example perhaps will contain the tackifier resins of aromatic ring, or the ultrafine dust of high index of refraction metal or metal oxide and the bonding agent method of mixing.Therefore, can form the acrylic acid tack coat that satisfies the refractive index requirement.
Can tack coat be connected with circuit polarizer, viewing angle compensation plate, quarter-wave plate or analog with suitable method.These methods comprise: with the tackifier components dissolved or decompose in the suitable single or mixture solution such as toluene or ethyl acetate solution, prepare the tackifier solution of about 10 to 40% weight, directly be coated onto material on by suitable distribution method such as projective method or coating process this solution; To be transferred to method on the material at the tack coat that forms on the spacer in the above described manner.Tack coat can be the lamination of composition or diverse layer.
The thickness of tack coat can suitably determine according to cohesive force.As a rule, select in the scope of the thickness of tack coat from 1 to 500 μ m, especially in the scope of 3 to 100 μ m, preferably in the scope of 5 to 50 μ m.Tack coat can comprise proper additive such as filler, pigment, colorant and antioxidant, and these adjuvants can be made up of natural or synthetic resin, glass fibre, beaded glass, metal powder or other inorganic powder according to application requirements.Tack coat also can contain transparent particulate, makes it can become the tack coat with dispersing property of light.The example of transparent particulate comprises inorganic particles and organic fine particles.Inorganic particles can be made by silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide etc., and has electric conductivity.Organic fine particles can be made by cross-linked polymer or non-cross-linked polymer or analog.Also can from inorganic particles and organic fine particles, suitably select the assembly of a kind of material or two or more materials to come as transparent particulate.
As shown in Figure 1, for an optical device is bonded on another optical device such as the liquid crystal cell, can on one or two opposed outer surface of optical device, tack coat 4 be set as required.From suppressing the viewpoint of boundary reflection, the refractive index N of tack coat D 20Be not less than 1.485 like that with preferably as above introducing.Surface for tack coat is exposed to outer situation, and tie layer surface can temporarily be covered by spacer 5, can prevent that therefore tack coat is not contaminated until the actual use of its input.Be exposed to outer situation for the material surface that forms optical device, exposed surface can bond or cover a surfacecti proteon film, makes material injury-free.
According to correlation technique, optical device can be used for many purposes.Particularly, optical device can be used to form liquid crystal indicator, and each pixel can be divided into a plurality of orientations territory in this device, and shows with circular polarisation mode.For example, liquid crystal indicator can form by the mode that optical device is arranged on of liquid crystal cell or each facing surfaces.In the method, from suppressing the viewpoint of boundary reflection, optical device is preferably by above-mentioned refractive index N D 20Being not less than 1.485 tack coat is bonded on the liquid crystal cell.
In introduction, when optical device was positioned at the viewable side of liquid crystal cell, optical device can be used as anti-dazzle photosphere or the anti-reflection layer that is positioned at the liquid crystal cell surface.But anti-dazzle photosphere scattering is by the exterior light of its surface reflection.Anti-reflection layer can suppress the surface reflection of exterior light.In other words, anti-dazzle photosphere and anti-reflection layer are used to prevent that surface reflection from dazzling the eyes, and the visuality that prevents to disturb the light of propagating by display device.Therefore, anti-dazzle photosphere and anti-reflection layer can both improve the performance that prevents the surface reflection interfere with visualization significantly.
There is no particular restriction to anti-dazzle photosphere or anti-reflection layer, and it can be formed by the suitable material layer with this function.For example, anti-dazzle photosphere can be formed by energy scattering and catoptrical low roughness structure.Anti-reflection layer can pass through method of evaporating or electro-plating method such as vacuum evaporation method, ion electroplating method or ion sputtering method, perhaps forms by suitable coating process such as sol-gel process.That is to say that anti-reflection layer can be formed by adhering film, adhering film is the laminated coating film by the inorganic oxide with different refractivity, and perhaps the coated film of low-index material such as fluoride is formed.
Also have, when forming liquid crystal indicator, the setting of optical device will make circularly polarized light enter into liquid crystal cell by the viewing angle compensation plate.Therefore, in optical device, the viewing angle compensation plate is arranged to apart from liquid crystal cell than near apart from circuit polarizer.When circuit polarizer was made up of the assembly of linear polarizer and quarter-wave plate, optical device had the structure of quarter-wave plate 13 between linear polarizer 11 and viewing angle compensation plate 3, as shown in Figure 1.Example 1
By the apparent surface of the polaroid made of vinyl alcohol of absorption iodine and refractive index (below use N D 20Represent) be that 1.485 cellulose triacetate is bonding and by its protection, thus formed linear polarizer (single transmissivity is 43%, and degree of polarization is 99.5%).The refractive index of being made up of the single axle drawn membrane of norbornene resin is that (the front lighting path difference is 140nm when light wavelength is 550nm for 1.513 quarter-wave plate, down with) be that 1.506 tack coat is bonded and stack on the surface of linear polarizer by refractive index, thereby formed a circuit polarizer.Viewing angle compensation plate (the front lighting path difference of forming as the biaxially oriented film of the norbornene resin of introducing above: 0nm, the thickness optical path difference: 100nm) bonded and stack on the surface of quarter-wave plate by above-mentioned tack coat, thus formed optical device.
Also have, tack coat forms as described below.By the butyl acrylate of 76 parts of weight of copolymerization and the acrylic acid of 4 parts of weight, the preparation counterpoise molecular weight is about 700000 acrylate copolymer.Acrylate copolymer with 100 parts of weight, the isocyanate crosslinking chemical of the dimethylbenzene tackifier of 20 parts of weight (by the PINE CRYSTAL KE-100 of Arakawa Chemical Industries Ltd. production) and 0.06 part of weight is (by Nippon Polyurethane Industries Co., Ltd. the coronate L of Sheng Chaning) be dissolved in the toluene, prepared the masking liquid of 13% weight.Masking liquid is coated onto on the lubricated mylar by applicator, and descends dry 3 minutes at 130 ℃, thereby has formed the thick tack coat of 20 μ m.Tack coat is attached on the predetermined surface again.Example 2
Can obtain four kinds of cholesteric liquid crystal polymer layers respectively by following method, it can direct reflection dextrad circularly polarized light, and its wavelength coverage is respectively (A) 650 to 750nm, and (B) 550 to 650nm, (C) 450 to 550nm, (D) 350 to 450nm.On the thick cellulose triacetate film of the 50 μ m that do not have birefringence (refractive index is 1.485) the thick vinyl alcohol layer of 0.1 μ m is set, the friction by rayon fabrics forms oriented film.On oriented film, apply the tetrahydrofuran solution of 20% weight of propylene thermotropism cholesteric liquid crystal polymer with linear bar, and carry out drying.Then, solution is heated to 150 ± 2 ℃ and keep 5 minutes to be orientated, and places then under the room temperature and cools off.Therefore, can be formed on the thick cholesteric liquid crystal polymer layer of 1.5 μ m that is orientated on the Grandjean structure.
Then, cholesteric liquid crystal polymer layer (A) and (B) 150 ± 2 ℃ down mutual thermo-compression bondings together and kept 2 minutes, this liquid crystal surfactant of two layers closely is in contact with one another simultaneously.Then, the cellulose triacetate film on the stripper crystal layer (B).At the exposed surface of liquid crystalline polymer layer (B), cholesteric liquid crystal polymer layer (C) and this surface 150 ± 2 ℃ down mutual thermo-compression bondings together and kept 2 minutes, this liquid crystal surfactant of two layers closely is in contact with one another.Then, the mutual in the above described manner thermo-compression bonding of layer that has bondd and cholesteric liquid crystal polymer layer (D) is in the same place.So just obtained circuit polarizer, the pitch of its cholesteric changes on thickness direction, and has circular dichroic (circular dichroism) in 400 to 700nm wavelength coverage.The mean refractive index of the liquid crystal polymer that is adopted is 1.575.Then, circuit polarizer and viewing angle compensation plate bond and are stacked together mutually in mode described in the example 1 by tack coat.Also have, tack coat can obtain 1.532 refractive index by the dimethylbenzene tackifier that adopt 40 parts of weight.Comparative example 1
Obtain a kind of optical device in example 1 described mode, difference is that linear polarizer and quarter-wave plate are 1.467 tack coat bonding by the refractive index that does not have tackifier and are stacked together mutually.Comparative example 2
Obtain a kind of optical device in example 1 described mode, difference is that linear polarizer and quarter-wave plate are 1.467 tack coat bonding by the refractive index that does not have tackifier and are stacked together mutually, and quarter-wave plate and viewing angle compensation plate are to be 1.467 tack coat bonding and to be stacked together mutually by the refractive index that does not have tackifier.Comparative example 3
Obtain a kind of optical device in example 2 described modes, difference is that cholesteric crystal circuit polarizer and viewing angle compensation plate are 1.467 tack coat bonding by the refractive index that does not have tackifier and are stacked together mutually.Evaluation test
With example 1 and 2 and comparative example 1 to 3 in the optical device that obtains replace the backlight side of the multiple domain type VA display panels bought on the market and the polarizer on the viewable side.Optical device is bonded on each opposite side of display panel by tack coat used in the example 1, thereby has formed liquid crystal indicator.Brightness and contrast by visually rank liquid crystal indicator liquid crystal.
Assessment result is as follows, and the size of brightness is followed successively by:
Example 2＞comparative example 3＞example 1＞ratio example 1＞comparative example 2,
The size of contrast is followed successively by:
Example 1＞comparative example 1＞ratio example 2＞example 2＞comparative example 3.
In contrast evaluation, the contrast of the panel of employing cholesteric crystal circuit polarizer is lower, and this is because the utilization of circularly polarized light is abundant inadequately in cholesteric.Yet, when the circularly polarized light that is reflected when backlight side re-uses, show just very bright, thereby improved visuality.
From the comparison of example and comparative example, can obviously see, when each lamination bonds by the tack coat with moderate refractive index, can keep higher contrast ratio.In addition, because the optical loss that boundary reflection causes reduces, brightness can improve a little.About contrast, when watching in narrower angle, the trend of raising is fairly obvious.

Claims (7)

1. optical device comprises:
Circuit polarizer;
The viewing angle compensation plate; With
Refractive index N D 20Be not less than 1.485 tack coat, described circuit polarizer and described viewing angle compensation plate are stacked together mutually by described tack coat.
2. according to the described optical device of claim 1, it is characterized in that described circuit polarizer is that the lamination by linear polarizer and quarter-wave plate constitutes, or is made of the cholesteric liquid crystal layers that is orientated on the Grandjean structure.
3. according to the described optical device of claim 2, it is characterized in that described linear polarizer and the described quarter-wave plate of forming described circuit polarizer are by described refractive index N D 20Being not less than 1.485 tack coat is stacked together mutually.
4. according to the described optical device of claim 1, it is characterized in that described viewing angle compensation plate is that its front lighting path difference is not more than 100nm on the basis of light of 550nm at wavelength, the optical path difference on the thickness direction is not less than 50nm.
5. according to the described optical device of claim 1, it is characterized in that described optical device also comprises at least one tack coat that is arranged at least one opposed outer surface, its refractive index N D 20Be not less than 1.485.
6. according to the described optical device of claim 1, it is characterized in that described tack coat is not higher than 20 ℃ tack coat by glass transition temperature and forms.
7. liquid crystal indicator comprises:
At least one optical device as claimed in claim 1;
Liquid crystal cell; With
Refractive index N D 20Be not less than 1.485 tack coat, described optical device is bonded at least one facing surfaces of described liquid crystal cell by described tack coat.
CN02104625A 2001-04-16 2002-02-08 Optical device and liquid crystal display unit Pending CN1381754A (en)

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CN1993647B (en) * 2005-03-15 2010-05-19 索尼株式会社 Retardation compensating plate, retardation compensator, liquid crystal display device, and projection image display apparatus
CN102768380A (en) * 2012-06-29 2012-11-07 天马微电子股份有限公司 Polarizer, liquid crystal display screen and liquid crystal display device
CN104407411B (en) * 2012-06-29 2017-03-15 天马微电子股份有限公司 A kind of polaroid, LCDs and liquid crystal indicator
CN109637384A (en) * 2019-01-22 2019-04-16 深圳市洲明科技股份有限公司 Display screen and its manufacturing method

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CN100410787C (en) * 2003-03-14 2008-08-13 奇美电子股份有限公司 Vertical nematic LCD device with multiple display zones by circular polarized light
KR101654322B1 (en) * 2009-07-24 2016-09-06 엘지디스플레이 주식회사 Liquid crystal display device having mirror function
CN112433286A (en) * 2019-08-26 2021-03-02 陕西坤同半导体科技有限公司 Polaroid and display device

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MY114245A (en) * 1993-07-19 2002-09-30 Teijin Ltd Laminate having improved polarization characteristics and release film used therefor

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1993647B (en) * 2005-03-15 2010-05-19 索尼株式会社 Retardation compensating plate, retardation compensator, liquid crystal display device, and projection image display apparatus
CN102768380A (en) * 2012-06-29 2012-11-07 天马微电子股份有限公司 Polarizer, liquid crystal display screen and liquid crystal display device
CN104407411B (en) * 2012-06-29 2017-03-15 天马微电子股份有限公司 A kind of polaroid, LCDs and liquid crystal indicator
CN109637384A (en) * 2019-01-22 2019-04-16 深圳市洲明科技股份有限公司 Display screen and its manufacturing method

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