CN101529319A - Liquid crystal panel and liquid crystal display apparatus - Google Patents

Abstract

The present invention discloses a liquid crystal panel that equipped a liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell and a second polarizer disposed on the opposite side of the liquid crystal cell, characterized in that at least one of the first polarizer and second polarizer is dyed with a dichromatic substance, and that the dichroic ratio thereof is in the range of 40 to 100. At least one of the first polarizer and second polarizer preferably exhibits polarization characteristics of 99% or higher polarization degree and 35 to 45% unit transmission. At least one of the first polarizer and second polarizer preferably exhibits a birefringence, nxy, of 0.015 to 0.030. This liquid crystal panel, as having these polarizers, realizes a high contrast ratio in the oblique direction, thereby excelling in image display performance.

Description

Liquid crystal panel and liquid crystal indicator

Technical field

The present invention relates to be used to the liquid crystal panel and the liquid crystal indicator of liquid crystal indicator etc.

Background technology

Liquid crystal indicator (below, be sometimes referred to as LCD) is to utilize the photoelectric characteristic of liquid crystal molecule to come the device of display text and image.LCD is equipped with the liquid crystal panel that has disposed polarization plates in the liquid crystal cells both sides usually.Polarization plates has polaroid.As this polaroid, be extensive use of polyvinyl alcohol oriented film with dichroic substance dyeing.Be disposed at each polarization plates of the both sides of holding liquid crystal unit, dispose according to the mode vertical usually with the absorption axes of this polaroid.

Above-mentioned liquid crystal panel can for example show black image under the situation of liquid crystal cells for normal black (Normally Black) pattern under the state that does not apply voltage.

Generally there is the low problem of oblique contrast in LCD.In order to address this problem, liquid crystal panel is wanted configuration phase difference film (for example referring to patent documentation 1).

But, extremely expect the further high performance of LCD on the market.That is, need can see liquid crystal indicator writings and image, that demonstrate higher contrast brightly from oblique.

Patent documentation 1: No. 3648240 communique of Japan's special permission

Summary of the invention

The object of the present invention is to provide high liquid crystal panel of oblique contrast and liquid crystal indicator.

In the design of liquid crystal panel, it is generally acknowledged that the dichromatism of polaroid is high more good more.The inventor etc. further investigate polaroid, find that the known understanding of the polaroid high with using dichroic ratio is opposite, compare the lower polaroid of dichroic ratio by using with polaroid in the past, can achieve the above object.

The invention provides a kind of liquid crystal panel, second polaroid that it possesses liquid crystal cells, is disposed at first polaroid of this liquid crystal cells one side and is disposed at this liquid crystal cells opposite side, wherein, the polaroid of at least one side in first polaroid and second polaroid dyes with dichroic substance, and its dichroic ratio is 40～100.

Liquid crystal panel of the present invention is in the polaroid of above-mentioned scope by using dichroic ratio, compares with liquid crystal panel in the past, and oblique contrast is significantly increased.The liquid crystal indicator of the present invention that possesses this liquid crystal panel can be sought wide visual angleization, the image visual excellence.

In addition, preferred version of the present invention is for providing a kind of above-mentioned liquid crystal panel, and wherein, the polaroid of at least one side in above-mentioned first polaroid and second polaroid shows that degree of polarization is more than 99% and the monolithic transmissivity is 35%～45% polarization characteristic.

In addition, preferred version of the present invention is for also providing a kind of above-mentioned liquid crystal panel, and wherein, the polaroid of at least one side in above-mentioned first polaroid and second polaroid shows Δ n _XyIt is 0.015～0.030 birefringence.

Wherein, Δ n _Xy=nx-ny.Nx represents the refractive index of the X-direction that the face of polaroid is interior.Ny represents the refractive index of the Y direction that the face of polaroid is interior.X-direction is the direction of the interior refractive index maximum of the face of polaroid, and Y direction is the direction vertical with this X-axis.

In addition, preferred version of the present invention is for providing a kind of above-mentioned liquid crystal panel, and wherein, the polaroid of at least one side in above-mentioned first polaroid and second polaroid comprises the stretching polymer film with dichroic substance dyeing.

In addition, preferred version of the present invention is for providing a kind of above-mentioned liquid crystal panel, wherein, above-mentioned stretching polymer film with dichroic substance dyeing can obtain through following operation at least: the operation that the hydrophilic polymer film that do not stretch is expanded, b) operation that the thin polymer film after expanding is dyeed with dichroic substance, c) make the crosslinked operation of thin polymer film after the dyeing, d) operation of the thin polymer film of washing after crosslinked, e) at expansion process to 3 times～5 times the operation that between the washing procedure thin polymer film is stretched to raw footage.

And preferred version of the present invention is for providing a kind of above-mentioned liquid crystal panel, and wherein, above-mentioned stretching polymer film comprises the polyvinyl alcohol film, and dichroic substance comprises iodine.

In addition, another preferred version of the present invention is for providing a kind of above-mentioned liquid crystal panel, and wherein, liquid crystal panel is of a size of more than 70 inches.

And another preferred version of the present invention is for providing a kind of above-mentioned liquid crystal panel, and wherein, above-mentioned liquid crystal cells contains the liquid crystal molecule of homeotropic alignment orientation under the state that does not have electric field.

In addition, another preferred version of the present invention wherein, possesses phase separation layer between the above-mentioned liquid crystal cells and first polaroid or second polaroid for a kind of above-mentioned liquid crystal panel is provided.

The index ellipsoid body of this phase separation layer preferably demonstrates the relation of nx 〉=ny＞nz.In addition, the Nz coefficient of this phase separation layer is preferably 1.1～8.0.And this phase separation layer preferably contains at least a resin that is selected from the group that polyimide based resin, polyester resin, norbornene resin and cellulosic resin form.Preferred especially above-mentioned phase separation layer contains polyimide based resin layer and cellulose resin layer.

And the present invention also provides a kind of liquid crystal indicator, and it has above-mentioned any liquid crystal panel.

Description of drawings

Fig. 1 is the contrast contour map of the liquid crystal panel of embodiment 1.

Fig. 2 is the contrast contour map of the liquid crystal panel of comparative example.

Fig. 3 is the curve map of the contrast of embodiment 1 and comparative example.

(a) shows the reference oblique view that downcuts the state of polaroid from the whole volume of oriented film among Fig. 4, (b) is the reference exploded perspective view that shows the configuration of liquid crystal cells, visual side polaroid and an opposite side polaroid.

Embodiment

Below the present invention will be described.

＜liquid crystal panel 〉

Liquid crystal panel of the present invention, the both sides of liquid crystal cells dispose polaroid (first polaroid and second polaroid) respectively.And, be provided with phase separation layer between preferred first polaroid of this liquid crystal panel and second polaroid.Formation about liquid crystal cells, polaroid and phase separation layer below is elaborated.

Preferred above-mentioned first polaroid is configured in the visual side of liquid crystal cells, and above-mentioned second polaroid is configured in the opposite side of visual side with liquid crystal cells.Preferably the mode according to the absorption axes direction perpendicular of absorption axes direction that makes above-mentioned first polaroid and above-mentioned second polaroid is configured.

Also have, in this manual,, the polaroid that is disposed at the liquid crystal cells both sides respectively is called " first polaroid ", " second polaroid " in order on term, to distinguish.Wherein, should " first ", the term of " second " and do not mean that the order, quality etc. of polaroid.

There is no particular limitation for the size of liquid crystal panel (visual picture dimension of liquid crystal panel), can suitably design according to its purposes.The present invention is applicable to that less picture dimension is to big picture dimension.Wherein, the present invention can be used for the liquid crystal panel of big picture effectively.Specifically, the size of liquid crystal panel (length of visual face diagonal) more preferably more than 80 inches, is preferably more than 100 inches especially for for example more than 70 inches.

The present invention can provide a kind of liquid crystal panel, even it is for the liquid crystal panel of this big picture, oblique contrast is also high.

＜liquid crystal cells 〉

As the liquid crystal cells that uses among the present invention, can adopt liquid crystal cells arbitrarily.As this liquid crystal cells, for example can enumerate the sort of simple matrix type that adopts in the active array type that uses thin film transistor (TFT) or the super-twist nematic liquid crystal indicator etc.

Above-mentioned liquid crystal cells preferably has a pair of substrate and the liquid crystal layer as display medium that is held in this a pair of substrate.Usually, on a substrate (active-matrix substrate), be provided with the control liquid crystal photoelectric characteristic on-off element (representative is TFT) and this on-off element provided the sweep trace of gate signal and the signal wire of source signal is provided.On another substrate (filter substrate), color filter is set.

Also have, above-mentioned color filter also can be arranged on the above-mentioned active matrix type substrate.But, when for example using the RGB3 color light source in the lighting device of liquid crystal indicator (field-sequential mode), above-mentioned color filter can omit.Also have, above-mentioned RGB3 color light source can also comprise polychromatic source.The interval of a pair of substrate can be controlled by spacer.Side that is connected with liquid crystal layer at each substrate can be provided with the oriented film that for example is made of polyimide.But, when utilization was controlled the initial orientation of liquid crystal molecule by the fringe field of the transparency electrode formation of patterning, above-mentioned oriented film can omit.

Above-mentioned liquid crystal cells preferably contains the liquid crystal molecule that carries out the homeotropic alignment orientation.In this manual, " homeotropic alignment " is meant the orientation vector of liquid crystal molecule because of the substrate of process orientation process and the interaction of liquid crystal molecule, and the result carries out the vertically state of (along normal direction) orientation with respect to base plan.

Also have, above-mentioned homeotropic alignment also comprises situation that the orientation vector of liquid crystal molecule tilts a little with respect to the substrate normal direction, is the situation that liquid crystal molecule has pre-dumping.When liquid crystal molecule had pre-dumping, this tilt angle (angle that departs from substrate normal) was preferably below 5 degree.By making tilt angle is below 5 degree, can obtain the high liquid crystal indicator of contrast.

Above-mentioned liquid crystal cells, the preferred index spheroid has the relation of nz＞nx=ny.As using the index ellipsoid body to have the driver module of the liquid crystal cells of nz＞nx=ny relation, for example can enumerate homeotropic alignment (VA) pattern, twisted-nematic (TN) pattern, vertical orientating type electrically conerolled birefringence (ECB) pattern, optical compensation birefringence (OCB) pattern etc.Preferred above-mentioned liquid crystal cells is homeotropic alignment (VA) pattern.

Also have, said n x represents the refractive index of X-direction in the liquid crystal aspect.Ny represents the refractive index of Y direction in the liquid crystal aspect.Nz represents the refractive index of direction vertical with above-mentioned X-direction and Y direction in the liquid crystal aspect.X-direction is the direction that the unilateral invagination of polarization is penetrated the rate maximum, and Y direction is the direction vertical with X-axis in the face.

The liquid crystal cells of above-mentioned VA pattern has utilized electro-optic birefringent effect.As the liquid crystal cells of VA pattern, make not exist the liquid crystal molecule of homeotropic alignment orientation under the electric field status in the electric field that is normal direction with respect to substrate, to respond.Specifically, as the VA mode liquid crystal unit that polarization plates is set in the liquid crystal cells both sides in the vertical mode of absorption axes direction, when normal black formula, do not exist under the state of electric field owing to make liquid crystal molecule, obtain black display along being the normal direction orientation with respect to substrate.On the other hand, as the liquid crystal cells of this VA pattern, exist under the state of electric field, liquid crystal molecule takes place along being that the mode that topple in 45 degree orientation is worked with respect to the polarization plates absorption axes, and is big thereby transmissivity becomes, and obtains white and shows.The liquid crystal cells of this VA pattern for example is recorded in Japan's special permission and disclose clear 62-210423 communique and Japan and speciallys permit and disclose in the flat 4-153621 communique.

The liquid crystal cells of above-mentioned VA pattern also can be to be formed with the electrode of slit or to use the surface to form bossed base material by use, thereby has carried out the liquid crystal cells of multiple domainization (multidomain).This liquid crystal cells for example is recorded in, and Japan's special permission discloses in the flat 11-258605 communique.

As this liquid crystal cells, for example can enumerate ASV (the Advanced Super View that Sharp Corporation makes, the Extra Vision liquid crystal flows) pattern, CPA (the Continuous Pinwheel Alignment that Sharp Corporation makes, the fireworks shape is arranged continuously) pattern, MVA (the Multi-domain VerticalAlignment that Fujitsu's (strain) makes, multi-domain vertical alignment) pattern, PVA (the Patterned Vertical Alignment that Samsung's (strain) makes, image is vertically adjusted) pattern, the EVA that Samsung's (strain) makes (Enhanced Vertical Alignment strengthens homeotropic alignment) pattern, SURVIVAL (the Super RangedViewing by Vertical Alignment) pattern that Sanyo Electric is made etc.

As above-mentioned liquid crystal cells, also can use the liquid crystal cells that is equipped on commercially available liquid-crystal apparatus.As the commercially available liquid crystal indicator that comprises VA mode liquid crystal unit, for example can enumerate LCD TV, trade name " AQUOS series " that Sharp Corporation makes, LCD TV, trade name " BRAVIA series " that Sony Corp makes, LCD TV, trade name " FORISSC26XD1 " that 32V molded breadth screen LCD TV, trade name " LN32R51B ", the NANAO CORPORATION that Samsung makes makes, the LCD TV that AU Optronics company makes, trade name " T460HW01 " etc.

＜polaroid 〉

" polaroid " in this instructions is meant the optics that natural light or polarized light is changed into rectilinearly polarized light.The light that preferred above-mentioned polaroid has incident is separated into two kinds of vertical polarized light components and a kind of polarized light component is seen through, the function of the another kind of polarized light component of absorption, reflection and/or scattering.

As mentioned above, polaroid of the present invention is set at the both sides (a visual side and an opposite side with visual side) of liquid crystal cells respectively.

Preferred first polaroid is configured in the visual side of liquid crystal cells, and second polaroid is configured in a side opposite with the visual side of liquid crystal cells.In addition, first polaroid that preferably is configured in visual side is provided with by its absorption axes mode parallel with the long limit of rectangle liquid crystal panel.

It is 40～100 that the polaroid that uses among the present invention satisfies dichroic ratio, and further preferably satisfying dichroic ratio is 45～95, and more preferably satisfying dichroic ratio is 50～70.This is that then the oblique contrast of liquid crystal indicator can significantly improve because if use the polaroid of the dichroic ratio that presents above-mentioned scope.Above-mentioned cognition is that the inventor waits discovery first.Specifically, this is because during dichroic ratio less than 40, and the polarization characteristic step-down on the other hand, if dichroic ratio surpasses 100, then can not reach the effect that significantly improves the liquid crystal indicator contrast.

Use presents reason that the contrast of LCD degree of polaroid of the dichroic ratio of above-mentioned scope uprises and indeterminate, but the inventor etc. have carried out following supposition.That is, infer that along angular orientation, and this has caused the absorption to oblique light to a part of dichroic substance (being iodo-complexes when using iodine), has improved contrast with respect to draw direction for polaroid of the present invention.The liquid crystal indicator that uses polaroid in the past is when showing black image, and therefore oblique light transmission and light leak takes place is difficult to realize real black display.In this, the liquid crystal indicator that uses polaroid of the present invention can prevent oblique light leak effectively when showing black image, therefore can realize high contrast.

In the present invention, as the polaroid of at least one side in first polaroid and second polaroid, use the polaroid of the dichroic ratio that shows above-mentioned scope.The preferred polaroid of the dichroic ratio that shows above-mentioned scope that uses is as first polaroid that is disposed at visual side.Preferred especially first polaroid and second polaroid all use the polaroid of the dichroic ratio that shows above-mentioned scope.

Also have, " dichroic ratio " is defined as DR=A (⊥)/A (||).Here, DR represents dichroic ratio.A (⊥) is that two identical polaroids are superimposed by the orthogonal mode of absorption axes and the absorbance of the vertical-type laminated polarizing sheet made.A (||) is the superimposed and absorbance of the parallel type laminated polarizing sheet made of mode that two identical polaroids are parallel to each other by absorption axes.

Also have, the concrete assay method of dichroic ratio in the embodiment record.

Above-mentioned dichroic ratio can be adjusted to desired scope by the transmissivity of stretching ratio and polaroid.For example, if in manufacturing process, improve stretching ratio, then can obtain the high polaroid of dichroic ratio.On the other hand, if reduce stretching ratio, then can obtain the low polaroid of dichroic ratio.In addition, if in manufacturing process, improve the transmissivity of polaroid, then can obtain the high polaroid of dichroic ratio by the dichroic substance concentration (for example iodine concentration) that reduces dye bath.On the other hand, if, then can obtain the low polaroid of dichroic ratio by improving the transmissivity that above-mentioned dichroic substance concentration reduces polaroid.Also have, also can pass through control stretching multiplying power and these two aspects of dichroic substance concentration, above-mentioned dichroic ratio is adjusted to desired scope.

The thickness of above-mentioned first polaroid and second polaroid is generally 5 μ m～50 μ m, is preferably 10 μ m～50 μ m.Be in the above-mentioned scope by the thickness that makes polaroid, can obtain the polaroid of physical strength excellence.

The monolithic transmissivity (T) of polaroid of the present invention (first polaroid and/or second polaroid) is preferably 35%～45%, and more preferably 39%～42%.This is because by making the monolithic transmissivity be in above-mentioned scope, can obtain the higher liquid crystal indicator of oblique contrast.

Also have, the monolithic transmissivity is based on the Y value that 2 of JI S Z 8701-1995 spends the tristimulus values in the visuals field.

The parallel transmissivity of above-mentioned polaroid is preferably 27%～36%, and more preferably 28%～34%.In addition, the vertical transmissivity of above-mentioned polaroid is preferably less than 0.0030%, more preferably below 0.0028%, is preferably below 0.0025% especially.By using parallel transmissivity and vertical transmissivity is the polaroid of above-mentioned scope, can obtain obviously high liquid crystal indicator of oblique contrast.

Above-mentioned polaroid is preferably below 0.020% in the vertical transmissivity at wavelength 440nm place, more preferably below 0.010%.In addition, above-mentioned polaroid is preferably less than 0.002% in the vertical transmissivity at wavelength 550nm place, more preferably below 0.0014%.Above-mentioned polaroid is preferably less than 0.003% in the vertical transmissivity at wavelength 650nm place, more preferably below 0.0014%.By the vertical transmissivity of using each wavelength place is the polaroid of above-mentioned scope, can obtain the liquid crystal indicator that the light leak of visible light in Zone Full is inhibited, oblique contrast is higher.Also have, the concrete assay method of parallel transmissivity and vertical transmissivity in the embodiment record.

The degree of polarization of polaroid of the present invention (P) is preferably more than 99%, more preferably more than 99.5%.By using degree of polarization is the polaroid of above-mentioned scope, can obtain the higher liquid crystal indicator of oblique contrast.

Above-mentioned degree of polarization can use spectrophotometer (color technical institute (strain) makes in the village, ProductName " DOT-3 ") to measure.The concrete assay method such as the embodiment of degree of polarization put down in writing.

In addition, polaroid of the present invention is at the Δ n at wavelength 1000nm place _Xy[1000] be preferably 0.015～0.030, more preferably 0.015～0.025.By using Δ n _Xy[1000] be the polaroid of above-mentioned scope, can obtain the higher liquid crystal indicator of oblique contrast.

Wherein, Δ n _XyBe defined as Δ n _Xy=nx-ny.Nx represents the refractive index of the X-direction that the face of polaroid is interior.Ny represents the refractive index of the Y direction that the face of polaroid is interior.X-direction is the direction of the interior refractive index maximum of the face of polaroid, and Y direction is the direction vertical with this X-axis.

Above-mentioned polaroid phase difference value in the face at wavelength 1000nm place is preferably 400nm～850nm, more preferably 500nm～800nm.Also have, above-mentioned interior phase difference value can be by birefraction (Δ n in the face _Xy[1000] and long-pending the obtaining of thickness (d (nm)).Phase difference value=Δ the n of polaroid in the face at wavelength 1000nm place _Xy[1000] * d.By the phase difference value in the use face is the polaroid of above-mentioned scope, can obtain the higher liquid crystal indicator of oblique contrast.

Satisfying the polaroid of the present invention of above-mentioned dichroic ratio scope etc. can make more easily, the therefore preferred stretching polymer film that uses with dichroic substance dyeing.

Specifically, polaroid of the present invention preferably uses the stretching polymer film that obtains through following operation.

That is, polaroid of the present invention can obtain through following operation: the operation that makes operation that the hydrophilic polymer film that do not stretch expands, dyes with the thin polymer film of dichroic substance after to this expansion, make the crosslinked operation of thin polymer film after this dyeing, wash the operation of this thin polymer film after crosslinked and be 3 times～5 times operation at above-mentioned expansion process between the washing procedure thin polymer film being stretched to total stretching ratio.

(hydrophilic polymer film)

As above-mentioned hydrophilic polymer film, have no particular limits the film that generally can use the resin combination film forming that will contain the polymkeric substance that possesses hydrophilic radical to obtain.As this film, for example can enumerate polyvinyl alcohol (PVA) (hereinafter referred to as PVA) class film, part formolation PVA class film, pet film, ethylene vinyl acetate copolymer class film and their partly-hydrolysed film etc.In addition, other material also can use the processed thing of PVA or the polyenoid oriented films such as desalination acid treatment thing of Polyvinylchloride etc.In these materials, preferred PVA class film is because its dichroic substance dyeability excellence.PVA is the polymkeric substance that the polyvinyl acetate (PVA) saponification that the vinyl acetate polyisocyanate polyaddition obtains is obtained.The PVA base polymer also can use above-mentioned PVA; Contain unsaturated carboxylic acid, olefines, vinyl ethers, unsaturated sulfonic acid salt etc. this can with the modified PVA of vinyl acetate copolymerized composition; The modified PVA that contains acetoacetyl, sulfonic group, carboxyl etc.; Modified PVA such as polyvinyl formal and polyvinyl acetal etc.

When using the PVA base polymer, this PVA base polymer can obtain by the vinyl esters base polymer that is obtained by vinyl ester monomer polymerizations such as vinyl acetates is carried out saponification.The PVA base polymer of preferred high saponification degree of this PVA base polymer and high polymerization degree is because its thermotolerance etc. are good.The saponification degree of PVA base polymer has no particular limits, and for example preferred saponification degree is 90 moles of %～100 mole %, and more preferably saponification degree is 95.0 moles of %～99.9 mole %.This saponification degree can be obtained by JIS K6726-1994.The average degree of polymerization of PVA base polymer has no particular limits, and for example is preferably 1000～8000, and more preferably 1200～3600, be preferably 1500～5000 especially.This average degree of polymerization can be obtained by JIS K 6726-1994.

PVA class film can obtain in the following manner: the resin combination that will contain the PVA base polymer is dissolved in water or/and in the suitable organic solvent such as DMSO, obtain by the casting method that makes this resin solution film forming.In addition, PVA class film can become film by the known one-tenth embrane methods such as extrusion molding outside the casting method.

In addition, with the method that above-mentioned PVA base polymer is the film of principal ingredient, for example can adopt method of putting down in writing in [embodiment 1] of the open 2001-315144 communique of Jap.P. as acquisition.

In the above-mentioned resin combination that contains the PVA base polymer, proper additive such as the plastifier that can allocate into, surfactant.As plastifier, for example can enumerate polyvalent alcohols such as ethylene glycol, glycerine etc.As surfactant, for example can enumerate non-ionics etc.By adding these plastifier and surfactant, can obtain the PVA class film of dyeability and stretchability excellence.The addition of plastifier and surfactant surpasses about 1 mass parts to 10 mass parts respectively with respect to PVA base polymer 100 mass parts.

Above-mentioned PVA class film also can directly use commercially available film.As commercially available PVA class film, for example can enumerate Network ラ レ (strain) manufacturing, trade name " Network ラ レ PVC ニ ロ Application Off イ Le system " East セ ロ (strain) manufacturing, trade name " ト one セ ロ PVC ニ ロ Application Off イ Le system ", Japan's synthetic chemical industry (strain) is made, trade name " day is closed PVC ニ ロ Application Off イ Le system " etc.

(expansion process)

Expansion process is the operation that makes the hydrophilic polymer film expansion that does not stretch.Below, describe as core with the manufacture method of using PVA class film, but polaroid of the present invention is not limited to use PVA class film to make, be suitable for too for other hydrophilic polymer film.

PVA class film can use non-stretched film.The whole volume of the PVA class film that this does not stretch batches and is the roller shape.The roller of the whole volume of this film can be arranged on upper reaches one side of expansion bath, imports in the expansion bath by conveying roller.

Expansion process is for not only removing the spot of PVA class film surface and preventing that water from making PVA class film expand, make dichroic substance described later to import uneven operation.

Be full of water in the expansion bath.Can in the solution of expansion bath, in the scope of not damaging effect of the present invention, add other material.

The liquid temperature of expansion bath is about and is heated to about 20～50 ℃ more preferably 30～40 ℃.The dip time of PVA class film in expansion bath was about about 1～7 minute.

Employed water during each is bathed as expansion bath and aftermentioned dye bath etc. preferably uses pure water.

(dyeing process)

Dyeing process is the operation of dipping in the PVA class film after expansion (being also referred to as absorption or contact etc.) dichroic substance.

After the PVA class film of above-mentioned expansion takes out, be imported into dye bath from expansion bath.

Be full of staining solution in the dye bath.Contain water and the dichroic substance that is dissolved in water in the staining solution.Also have, in staining solution, also can add the organic solvent that intermiscibility is arranged with glassware for drinking water slightly.

The addition of dichroic substance has no particular limits, with respect to water 100 mass parts, and the ratio of preferred 0.0001～5 mass parts, the more preferably ratio of 0.001～3 mass parts, the ratio of preferred especially 0.01～2 mass parts.

As above-mentioned dichroic substance, can use known in the past material, for example can enumerate iodine or organic dyestuff etc.As organic dyestuff, for example can enumerate polymethine pigment, anthocyanidin, merocyanine pigment, examine merocyanine pigments, alopolar pigment, half anthocyanidin, styryl pigment, azo class pigment etc. as if red cyanines pigment, three.

This dichroic substance can be a kind of, also can be two or more and usefulness.In addition, preferred dichroic substance is water miscible.As water miscible dichroic substance, for example can illustration make to have imported substituent organic dyestuff of water wettability such as sulfonic group, amino, hydroxyl etc. and make the state of the salt of free acid and alkali metal salt thereof, ammonium salt, amine and use.

Wherein, as dichroic substance, preferably use iodine.By using iodine, can obtain in the almost whole zone of visible light, showing the polaroid of dichromatism receptivity easily.

When using iodine as dichroic substance, the addition of iodine is preferably 0.01～0.15 mass parts with respect to water 100 mass parts, more preferably 0.01～0.05 mass parts.In this scope, if the addition of iodine increases, then the result can obtain the low polaroid of transmissivity.In addition, in above-mentioned scope, if reduce the addition of iodine, then the result can obtain the high polaroid of transmissivity.

In addition, can also add iodide in the staining solution.As iodide, for example can enumerate potassium iodide, lithium iodide, sodium iodide, zinc iodide, silver iodide, lead iodide, cupric iodide, barium iodide, calcium iodide, stannic iodide, titanium iodide etc.Iodide preferably use potassium iodide.The addition of iodide is preferably 0.05～0.5 mass parts with respect to water 100 mass parts, more preferably 0.1～0.3 mass parts.Be in this scope by the addition that makes iodide, can obtain having above-mentioned transmissivity and the high polarization plates of degree of polarization.

In addition, also can staining solution, add reaction promoter from the dyeing efficient that can further improve dichroic substance.When using iodine as dichroic substance, reaction promoter is preferably for example boron compound such as boric acid or borax.In addition, when using organic dyestuff as dichroic substance, reaction promoter for example is preferably boric acid (sodium sulphate) etc.When using these dyeing assistants, its addition is preferably 0.1～10 mass parts with respect to water 100 mass parts of staining solution.

The dip time of PVA class film in dye bath has no particular limits, be preferably 20 seconds～and about 1800 seconds.In addition, the liquid temperature of dye bath is preferably about 20 ℃～60 ℃, about more preferably 30 ℃～50 ℃.If the temperature of dye bath is too high, then film possibility fusion is if cross low then dyeability decline.Also have, dyeing process can carry out in being divided into 2 dye baths more than the groove.

In addition, also can stretch to film in this dye bath, the stretching ratio of this moment is about 1.5～3.0 times.

(crosslinked operation)

Crosslinked operation is the operation for the crosslinking chemicals such as the thin film dipped boric acid of PVA class that flooded dichroic substance.

After the above-mentioned PVA class film that has flooded dichroic substance taken out from dye bath, import in the crosslinked bath.

Be full of crosslinker solution in the crosslinked bath.Crosslinker solution contains water and is dissolved in the crosslinking chemical of water.In above-mentioned crosslinker solution, also can add the organic solvent that intermiscibility is arranged with glassware for drinking water.The addition of crosslinking chemical has no particular limits in the crosslinker solution, is preferably the ratio of 0.5～10 mass parts, the more preferably ratio of 1～7 mass parts with respect to water 100 mass parts.

As above-mentioned crosslinking chemical, can use known in the past material, for example can enumerate boron compounds such as boric acid, borax.These materials can use a kind of, also can use simultaneously more than two kinds.But, crosslinking chemical preferably contains boric acid at least.

In the face of polaroid, obtain the consideration of uniform characteristic aspect, can also add iodide in the cross-linking agent solution.As these iodide, can from above-mentioned dyeing process, suitably select for use in the illustrative material.Wherein, as the iodide of crosslinker solution, preferably contain potassium iodide.As the addition of iodide in the crosslinker solution, preferably with respect to water 100 mass parts, iodide are 0.5～10 mass parts, more preferably 1～7 mass parts.

The liquid temperature of crosslinked bath has no particular limits, and is preferably 20～70 ℃ scope.The dip time of film has no particular limits, be preferably 60 seconds～and about 1200 seconds, about more preferably 200 seconds～400 seconds.Also have, crosslinked operation can be carried out in being divided into 2 crosslinked baths more than the groove.

In addition, also can stretch to film in this crosslinked bath, the stretching ratio of this moment is about 2～4 times.

(stretching process)

Stretching process is the operation of PVA class film being carried out uniaxial tension.

Stretch processing or is selected from 2 above operations of above-mentioned expansion process to the washing procedure and carries out preferably in any operation of above-mentioned expansion process between the crosslinked operation.Wherein, preferably at expansion process to the crosslinked operation, at least dyeing handle and crosslinking Treatment in implement stretch processing.

In addition, also can be at expansion process between the crosslinked operation, being provided with in addition with the stretch processing is the stretching process of fundamental purpose.Perhaps after crosslinked operation, being provided with in addition with the stretch processing is the stretching process of fundamental purpose.

For stretch processing, (also having, when implementing stretch processing in 2 above operations, is total stretching ratio that their add up to preferably to be stretched to respect to the former length of the PVA class film that does not stretch (import expansion process before PVA class film) about 3 times～5 times.Together following), and then about more preferably 4 times～5 times.As polaroid in the past, evenly be orientated on draw direction in order to make dichroic substance, stretch for about 6～7 times by total stretching ratio and make.In the present invention, the stretching by 3 times～5 times can obtain the polaroid that oblique contrast significantly improves.Its effect and indeterminate, but by being stretched to about 3 times～5 times, the orientation of a part of dichroic substance is (that is, a part of dichroic substance is along the draw direction orientation) in a jumble, and the result can obtain having the polaroid of above-mentioned dichroic ratio.Because a part of dichroic substance is along same direction orientation in the above-mentioned polaroid, therefore from oblique when watching the liquid crystal indicator that uses this polaroid, light transmission and improved contrast.

In addition, when carrying out above-mentioned this stretching than low range, compare, can obtain the big film of width, be the polaroid of wide cut with the situation that the sort of high magnification (6～7 times) in the past stretches.Also have, above-mentioned width is meant the width of the direction vertical with draw direction.

Therefore, utilize polaroid of the present invention, also can provide large-sized liquid crystal panel more than 70 inches by a slice polaroid.

If be specifically described, the polaroid of oriented film system can stretch to the hydrophilic polymer film that has adsorbed dichroic substance by mode as mentioned above and make.

During by the machine-building polaroid, with Rack and the very long whole volume of not stretching (MD direction) stretching longitudinally.Whole volume 1 after the stretch processing forms absorption axes A as Fig. 4 (a) draw direction that is shown in (being the MD direction) in reduced width.

The mode of general liquid crystal panel such as Fig. 4 (b) is provided with, that is, the absorption axes A1 of visual side polaroid 11 is parallel with the long limit of liquid crystal cells 2, and the absorption axes A2 of the polaroid 12 of an opposite side is vertical with the long limit of liquid crystal cells 2.

The polaroid 12 of a described visual side polaroid 11 and an opposite side can obtain by like that above-mentioned former oriented film 1 is cut into rectangle shown in Fig. 4 (a).Wherein, fasten consideration from the pass of absorption axes, the polaroid 12 of an opposite side carries in the following manner to be cut, that is, make the Width (TD direction) of above-mentioned former oriented film 1 become the long limit of this polaroid 12.

Therefore, visual long edge lengths of liquid crystal panel is controlled as the long limit of the polaroid 12 of an opposite side, the i.e. width of whole volume 1.Thereby the width of former oriented film 1 can't form bigger restriction to the size of liquid crystal panel.

In this, utilize polarization film of the present invention, can form as mentioned above than the wideer width of polaroid in the past, thereby the maximization that also can realize the liquid crystal panel size compared with the past.

Also have, do not implement stretch processing to any operation between the crosslinked operation and when in addition stretching process being set,, can be any means in wet type pulling method or the dry type stretching method as its drawing process at expansion process.The wet type pulling method is the mode that in stretch bath PVA class film is stretched.The dry type stretching method is the mode that in air the PVA film after moisture is stretched.Under the situation of wet type pulling method, the solution of stretch bath has no particular limits, and for example can use the solution that has added various slaines, boron, zinc compound etc.As the solvent of this solution, make water, ethanol or various organic solvent.The liquid temperature of this stretch bath is preferably for example 40～67 ℃, more preferably 50～62 ℃.On the other hand, under the dry type stretching situation preferred 50～180 ℃.

(washing procedure)

Washing procedure is the operation that rinses out through the unwanted residue (boron etc.) that adheres on the PVA class film of above-mentioned each operation.

Above-mentioned after crosslinked PVA class film takes out from crosslinked bath, be imported in the washing bath.

Usually be full of water in the washing bath.In addition, also can in the solution of washing bath, add proper additive in case of necessity.

The liquid temperature of washing bath is preferably about 10 ℃～60 ℃, about more preferably 15 ℃～40 ℃.In addition, there is no particular limitation for the number of times of carrying out washing treatment, can implement repeatedly.

In addition, when PVA class film was taken out from expansion bath, dye bath, crosslinked bath, washing bath, in order to prevent to take place under the fluid drips, preferred enforcement handled except that liquid.Handle as removing liquid, for example can use in the past known pinch roll etc.In addition, handling as removing liquid, also can be to remove method such as liquid by air knife.Remove the liquid processing by implementing these, the unnecessary liquid that adheres on the film can be removed.

(drying process)

Drying process is that the PVA class film after the washing is carried out dry operation.

After PVA class film after the above-mentioned washing taken out from washing bath, import in the drying device.

Above-mentioned drying can be used suitable methods such as air dry, air-dry, heat drying.Usually the preferred heat drying that adopts.In heat drying, for example heating-up temperature is about 20～80 ℃, is preferably drying time about 1～10 minute.

By above each treatment process, can obtain polaroid of the present invention.

Under the situation of the PVA class film of using iodine staining, its content of iodine is preferably 1.8～5.0 quality %, more preferably 2.0～4.0 quality %.Content of iodine is the transmissivity that the polaroid of above-mentioned scope has preferable range, and by using this polaroid, can obtain the high liquid crystal indicator of oblique contrast.

In addition, when above-mentioned PVA class film contained potassium, its potassium content was preferably 0.2～1.0 quality %, more preferably 0.3 quality %～0.9 quality %.Potassium content is that the polaroid in the above-mentioned scope has the transmissivity of preferable range, and has higher degree of polarization.

And when above-mentioned PVA class film contained boron, its boron content was preferably 0.5～3.0 quality %, more preferably 1.0～2.8 quality %.Boron content is the transmissivity that the polaroid of above-mentioned scope has preferable range, and has higher degree of polarization.

Above-mentioned polaroid also can directly use, but usually in use, is that the optical thin film of known various optical processing uses as having applied in the past.About this optical processing, just have no particular limits so long as satisfy the processing of needed optical characteristics, for example can following a)～d) the sort of processing of illustration.A) stacked purpose is to protect the transparent protective seam of polaroid on the single face of polaroid or two sides.B) on the single face of the surface (face relative) of above-mentioned transparent protective seam or polaroid or two sides, apply surface treatments such as being coated with processing, antireflection processing, release treatment firmly with the face of bonding polaroid.C) stacked is the aligned liquid-crystal layer of purpose with the viewing angle compensation.D) the stacked tack coat that is used for stacked other film.

Usually, polaroid is that form with the polarization plates of its two sides or the stacked protective clear layer of single face provides.As the material of protective clear layer, be preferably the layer of aspect excellences such as the transparency, physical strength, thermal stability, moisture shielding, isotropy.As the material that forms protective clear layer, for example can enumerate polyester polymers such as polyethylene terephthalate or Polyethylene Naphthalate; Cellulosic polymer such as diacetyl cellulose or tri acetyl cellulose; Acrylic polymerss such as polymethylmethacrylate; Polystyrene or acrylonitrile styrene copolymer styrenic polymers such as (AS resins); Polycarbonate polymer etc.In addition, as the material that forms above-mentioned protective clear layer, can also enumerate tygon, polypropylene, have the polyolefin polymers of the polyolefin, ethylene propylene copolymer and so on of lopps or norborene structure; The polyvinyl chloride-base polymkeric substance; Acylamide polymer such as nylon or aromatic polyamide; The acid imide polymkeric substance; The sulfone base polymer; The polyether sulfone polymkeric substance; Polyether-ether-ketone polymer; The polyphenylene sulfide base polymer; Vinyl alcohol polymer; The vinylidene chloride base polymer; The polyvinyl butyral base polymer; The arylide analog copolymer; The polyoxymethylene base polymer; Epoxide polymer; The blend of above-mentioned polymkeric substance etc.In addition, protective clear layer can be the cured layer of thermohardening type or ultraviolet hardening polymkeric substance.As the polymkeric substance of above-mentioned cured layer, can enumerate acrylic compounds, polyurethanes, acroleic acid polyurethane class, epoxies, silicone based etc.In these materials,, preferably the tri acetyl cellulose that saponification is handled has been carried out on the surface with alkali etc. as protective clear layer.

The thickness of protective clear layer has no particular limits, and is generally below the 500 μ m, is preferably 1～300 μ m, more special 5～200 μ m that are preferably.In addition, consider, preferably saponification is carried out on the surface of protective clear layer and handled with alkali etc. from aspects such as polarization characteristic, permanance and adhesion properties raisings.

＜phase separation layer 〉

The phase separation layer that uses among the present invention is configured between above-mentioned first polarization plates and above-mentioned second polarization plates.In this manual, " phase separation layer " is meant in the face and/or thickness direction has the transparent layer of phase differential.

This phase separation layer is configured between the liquid crystal cells and first polaroid, or/and between the liquid crystal cells and second polaroid.Phase separation layer can be an individual layer, also can be sandwich construction.

In the face of above-mentioned phase separation layer under wavelength 590nm and/or the phase difference value of thickness direction be more than the 10nm.The thickness of above-mentioned phase separation layer is preferably 0.5 μ m～200 μ m, and the transmissivity of above-mentioned phase separation layer under wavelength 590nm (T[590]) be preferably more than 90%.

Preferred above-mentioned phase-contrast film is configured between above-mentioned liquid crystal cells and above-mentioned first polarization plates (for example being arranged on the polaroid of the visual side of liquid crystal cells).In addition, preferably dispose above-mentioned phase separation layer according to the mode of the absorption axes direction perpendicular of slow-axis direction that makes above-mentioned phase separation layer and adjacent polaroid.Therefore, when above-mentioned phase separation layer was configured between above-mentioned liquid crystal cells and above-mentioned first polarization plates, preferably the mode according to the absorption axes direction perpendicular of the slow-axis direction of above-mentioned phase separation layer and above-mentioned first polaroid was configured.

The birefraction spheroid of above-mentioned phase separation layer shows the relation of nx 〉=ny＞nz.In this manual, " relation that shows nx 〉=ny＞nz " is meant the relation of demonstration nx=ny＞nz or the relation (being also referred to as negative biaxiality) of nx＞ny＞nz.

Also have, said n x represents the refractive index of the X-direction that the face of phase separation layer is interior.Ny represents the refractive index of the Y direction that the face of phase separation layer is interior.Nz represents the refractive index of the direction vertical with above-mentioned X-direction and Y direction.X-direction is the direction of the interior refractive index maximum of the face of phase separation layer, and Y direction is the direction vertical with X-axis in this face.

The preferred phase separation layer that uses the birefraction spheroid to show nx＞ny＞nz relation.Have the phase separation layer of above-mentioned birefraction spheroid by use, only configuration a slice phase separation layer between first polaroid and second polaroid can compensate liquid crystal cells to heavens.Therefore, can obtain slim and low-cost liquid crystal panel.In addition, because the stacked number of times of phase separation layer is few, the slow axis of phase separation layer is little from the possibility that desired position departs from, and can obtain the higher liquid crystal indicator of oblique contrast.This liquid crystal panel that only uses a slice phase separation layer to compensate mode is called " liquid crystal panel that a slice is compensation ".

When the birefraction spheroid of above-mentioned phase separation layer shows concerning of nx=ny＞nz, the Re[590 of above-mentioned phase separation layer] not enough 10nm, be preferably below the 5nm.When the birefraction spheroid of above-mentioned phase separation layer shows concerning of nx＞ny＞nz, the Re[590 of above-mentioned phase separation layer] be more than the 10nm, to be preferably 20nm～80nm, more preferably 30nm～70nm is preferably 30nm～60nm especially.By using Re[590] be the phase separation layer of above-mentioned scope, can obtain front and oblique contrast height, have the liquid crystal indicator of excellent display characteristic.

The Rth[590 of above-mentioned phase separation layer] can suitably set according to the phase difference value of liquid crystal cell thickness direction.Above-mentioned Rth[590] be preferably 100nm～400nm, more preferably 150nm～350nm is preferably 150nm～300nm especially.By using Rth[590] be the phase separation layer of above-mentioned scope, can obtain oblique contrast height, have the liquid crystal indicator of excellent display characteristic.

When the birefraction spheroid of above-mentioned phase separation layer shows concerning of nx＞ny＞nz, the Rth[590 of phase separation layer] than its Re[590] big.That is, the Nz coefficient of above-mentioned phase separation layer is greater than 1.Above-mentioned Nz coefficient is preferably and surpasses 1.1 and be below 8, and more preferably 2～7, be preferably 3～6 especially.By using the Nz coefficient is the phase separation layer of above-mentioned scope, can obtain the liquid crystal panel of good a slice compensation way.And, be the phase separation layer of above-mentioned scope by using the Nz coefficient, can obtain positive and oblique contrast height, have the liquid crystal indicator of excellent display characteristic.

Also have Re[590] be meant the phase difference value in the face of phase separation layer under 23 ℃ and the wavelength 590nm.Pass through Re[590]=(nx-ny) * d (d is the thickness (nm) of phase separation layer) obtains.Rth[590] be meant the phase difference value of the thickness direction of phase separation layer under 23 ℃ of following wavelength 590nm.Pass through Rth[590]=(nx+ny)/2}-nz) * d (the same) obtains.The Nz coefficient is by Nz=(nx-nz)/(nx-ny) obtain.

As the material that forms above-mentioned phase separation layer,, then can use suitable material arbitrarily so long as the index ellipsoid body shows the material of nx 〉=ny＞nz relation.Above-mentioned phase separation layer preferably contains at least a resin that is selected from the group that polyimide based resin, polyester resin, norbornene resin and cellulosic resin form.By these resin materials are made sheet film, can be met the phase separation layer of above-mentioned index ellipsoid body.

(polyimide based resin)

When above-mentioned polyimide based resin forms sheet by solvent casting method, in the evaporation process of solvent, the easy spontaneous orientation of molecule.Therefore, use the index ellipsoid body of the film that polyimide based resin forms show the relation of nx=ny＞nz and can form extremely thin.Therefore, the film that contains this polyimide based resin can be suitable as phase separation layer.The thickness that contains the phase separation layer of polyimide based resin is preferably 0.5 μ m～10 μ m, more preferably 1 μ m～5 μ m.Birefraction (the Δ n of thickness direction that contains the phase separation layer of above-mentioned polyimide based resin _Xz[590]) be preferably 0.01～0.12, more preferably 0.02～0.08.This polyimide resin can obtain by the method for record in No. 5,344,916, the United States Patent (USP) for example.

In addition, the index ellipsoid body that contains the film of above-mentioned polyimide based resin shows the relation of nx=ny＞nz.Therefore, need not implement complicated pulling method to this film, and, just can obtain the film (phase separation layer) that the index ellipsoid body shows nx＞ny＞nz relation by this film being implemented common vertical uniaxial tension method or horizontal uniaxial tension method.Above-mentioned index ellipsoid body shows the phase separation layer of nx＞ny＞nz relation, even be made into wide cut in large-scale liquid crystal indicator purposes, slow axis also reaches evenly easily at Width, even paste polaroid, the axle deviation is also little.Therefore, by using above-mentioned phase separation layer, can obtain the high liquid crystal indicator of oblique contrast.

Above-mentioned polyimide based resin preferably has hexafluoro isopropylidene and/or trifluoromethyl.Preferred above-mentioned polyimide based resin has the repetitive of following general formula (I) expression or the repetitive of following general formula (II) expression at least.Contain the transparency of the polyimide based resin of these repetitives, to the dissolubility excellence of usual solvents, the birefraction of thickness direction is big.

[Chemical formula 1]

[Chemical formula 2]

During above-mentioned general formula (I) reached (II), G and G ' represented to be selected from covalent bond, CH independently of one another ₂Base, C (CH ₃) ₂Base, C (CF ₃) ₂Base, C (CX ₃) ₂(wherein, X is a halogen to base.), CO base, O atom, S atom, SO ₂Base, Si (CH ₂CH ₃) ₂Base and N (CH ₃) group in the group formed of base.G and G ' can be identical respectively, also can be different.

In the above-mentioned general formula (I), L is a substituting group, and e represents that it replaces number.L is for for example halogen, carbon number are that 1～3 alkyl, carbon number are 1～3 halogenated alkyl, phenyl or substituted-phenyl, has when a plurality of, and is identical or different respectively.E is 0 to 3 integer.

In the above-mentioned general formula (II), Q is a substituting group, and f represents that it replaces number.Q is atom or the group that is selected from the group that for example hydrogen, halogen, alkyl, substituted alkyl, nitro, cyano group, sulfane base, alkoxy, aryl, substituted aryl, alkyl ester group and substituted alkyl ester group formed.When Q is a plurality of, identical or different respectively.F is 0 to 4 integer, and g and h are respectively 1 to 3 integers.

Above-mentioned polyimide based resin can obtain by the reaction of for example tetracarboxylic dianhydride and diamines.The repetitive of above-mentioned general formula (I) can obtain by diamines is reacted with the tetracarboxylic dianhydride with at least 2 aromatic rings.As this diamines, for example can enumerate 2,2 '-two (trifluoromethyl)-4,4 '-benzidine.The repetitive of above-mentioned general formula (II) can obtain by the tetracarboxylic dianhydride is reacted with the diamines with at least 2 aromatic rings.As this tetracarboxylic dianhydride, for example can enumerate 2,2 '-two (3,4-dicarboxyl phenyl) hexafluoro propionic acid dianhydride.Above-mentioned reaction can be the chemical imidizate that is for example undertaken by 2 steps, also can be the hot-imide that is undertaken by 1 step.

Above-mentioned tetracarboxylic dianhydride can select suitable kind arbitrarily.As above-mentioned tetracarboxylic dianhydride, for example can enumerate 2,2-two (3,4-dicarboxyl phenyl) hexafluoro propionic acid dianhydride, 3,3 ', 4,4 '-benzophenone tetracarboxylic dianhydride, 2,3,3 ', the 4-benzophenone tetracarboxylic dianhydride, 2,2 ', 3,3 '-benzophenone tetracarboxylic dianhydride, 2,2 '-two bromo-4,4 ', 5,5 '-biphenyl tetracarboxylic dianhydride, 2,2 '-two (trifluoromethyl)-4,4 ', 5,5 '-biphenyl tetracarboxylic dianhydride, 3,3 ', 4,4 '-biphenyl tetracarboxylic dianhydride, 4,4 '-two (3,4-dicarboxyl phenyl) ether dianhydride, 4,4 '-oxidation, two O-phthalic acid dianhydrides, 4,4 '-two (3,4-dicarboxyl phenyl) sulfonic acid dianhydride, two (2,3-dicarboxyl phenyl) formic acid dianhydride, two (3,4-dicarboxyl phenyl) diethylsilane acid dianhydride etc.

Above-mentioned diamines can be selected suitable kind arbitrarily.As above-mentioned diamines, for example can enumerate 2,2 '-two (trifluoromethyl)-4,4 '-benzidine, 4,4 '-benzidine, 4,4 '-tetramethyl triaminotriphenyl methane NH2,4,4 '-(9-fluorenylidene)-diphenylamine, 3,3 '-two chloro-4,4 '-diaminodiphenyl-methane, 2,2 '-two chloro-4,4 '-benzidine, 4,4 '-diamino-diphenyl ether, 3,4 '-diamino-diphenyl ether, 4,4 '-diamino diphenyl sulfone, 4,4 '-diamino-diphenyl thioether etc.

The weight-average molecular weight of above-mentioned polyimide based resin (Mw) is preferably 20000～180000.The weight-average molecular weight of above-mentioned polyimide based resin (Mw) is launched the weight-average molecular weight of the polyethylene oxide standard of solvent with dimethyl formamide solution (add 10mM lithium bromide and 10mM phosphoric acid and mix formation 1L dimethyl formamide solution) conduct.

The imidizate rate of above-mentioned polyimide based resin is preferably more than 95%.The imidizate rate can be from being derived from as polyimide precursor, being that the proton peak of polyamic acid is obtained with the integrated intensity ratio of the proton peak that is derived from polyimide.

The phase separation layer that contains above-mentioned polyimide based resin can obtain by any suitable forming and machining method.The phase separation layer that preferably contains above-mentioned polyimide based resin is the polyimide film that is configured as sheet by solvent casting method to be stretched make.Pulling method can adopt vertical uniaxial tension method or horizontal uniaxial tension method etc.The temperature (draft temperature) that above-mentioned polyimide film is stretched is preferably 120 ℃～200 ℃.In addition, the multiplying power (stretching ratio) that above-mentioned polyimide film is stretched is preferably above 1 and below 3 times.

＜liquid crystal indicator 〉

Liquid crystal indicator of the present invention possesses above-mentioned liquid crystal panel.

Liquid crystal indicator of the present invention is any kind in infiltration type, reflection-type or the semi-transmission type.

For example, under the situation of transmission type liquid crystal display device, the back light unit that possesses liquid crystal panel at least and be disposed at an opposite side with visual side of this liquid crystal panel.Also have, back light unit can be under formula, also can be side-light type.

Under the situation of formula, back light unit preferably possesses light source, reflective film, diffuser plate, prismatic lens and brightness enhancing films under adopting.When adopting mode backlight, preferred back light unit is except said structure, at least and then possess light guide plate and reflector.

Liquid crystal indicator of the present invention can be used for purposes widely.Its purposes is for for example, OA equipment such as PC monitor, notebook computer, duplicating machine; Portable units such as portable phone, clock and watch, digital camera, portable information terminal (PDA), portable game; Household electrical appliance such as video recorder, televisor, electric furnace; Vehicle mounted equipment such as backsight monitor, auto-navigation system monitor, automobile audio; Commercial shop with information with presentation devices such as monitors; Supervision is with alert devices such as monitors; Nurse, Medical Devices etc. such as nurse monitor, medical monitor.

The purposes of preferred liquid crystal indicator of the present invention is a televisor.The picture dimension of above-mentioned televisor (catercorner length of rectangle picture) is preferably more than 70 inches, more preferably more than 80 inches, is preferably especially more than 100 inches.

Embodiment

The invention will be further described with embodiment and comparative example.Also have, the present invention also not only is confined to following embodiment.

Each analytical approach of using in embodiment and the comparative example is as follows.

(1) assay method of the monolithic transmissivity of polaroid:

Measure with spectrophotometer [color technical institute (strain) makes in the village, ProductName " DOT-3 "].The monolithic transmissivity is based on the Y value that 2 of JIS Z 8701-1995 spends the tristimulus values in the visuals field.

(2) assay method of the vertical transmissivity the when degree of polarization of polaroid and wavelength 440nm, 550nm and 660nm:

Measure the parallel transmissivity (H of polaroid with spectrophotometer [color technical institute (strain) makes in the village, ProductName " DOT-3 "] ₀) and vertical transmissivity (H ₉₀), by formula: degree of polarization (%)={ (H ₀-H ₉₀)/(H ₀+ H ₉₀) ^1/2* 100 obtain.Parallel transmissivity (H ₀) be the value of the transmissivity of the superimposed parallel type laminated polarizing sheet of making of mode that two identical polaroids are parallel to each other by absorption axes.Vertical transmissivity (H ₉₀) be with the value of two identical polaroids by the transmissivity of the superimposed vertical-type laminated polarizing sheet of making of the orthogonal mode of absorption axes.Also have, these transmissivities are the 2 degree visuals field (illuminant-C) of adopting JIS Z 8701-1982, have carried out the Y value that the visual sense degree is proofreaied and correct.

(3) mensuration of the dichroic ratio of polaroid

Measure the T of polaroid with spectrophotometer [color technical institute (strain) makes in the village, ProductName " DOT-3 "] _AveAnd P, obtain by following formula.

Dichroic ratio DR=A (⊥)/A (||)=log{ (T _Ave/ 100) * (1-P/100) }/log{ (T _Ave/ 100) * (1+P/100) }.

Also has T _AveBe the mean value of the monolithic transmissivity of two polaroids of use in measuring, P is above-mentioned degree of polarization.

(4) each element (I, K) Determination on content method

Measure the circular specimen of diameter 10mm under the following conditions by x-ray fluorescence analysis, utilize the typical curve made from the standard test portion in advance to obtain each constituent content from the X ray intensity that determines.

Analytical equipment: the fluorescent x-ray analyzer (XRF) that electric machine industry of science is made, ProductName " ZSX100e "

Anticathode: rhodium

Analyzing crystal: lithium fluoride

Exciting light energy: 40kV-90mA

Iodine is measured line: I-LA

Potassium is measured line: K-KA

Quantivative approach: FP method

2 θ horn: 103.078deg (iodine), 136.847deg (potassium)

Minute: 40 seconds

(5) phase difference value of phase separation layer (Re[λ], Rth[λ]) and Nz coefficient, T[590] assay method:

Use prince's instrumentation machine (strain) manufacturing, the device of commodity " KOBRA21-ADH " by name is measured down at 23 ℃.Also have, mean refractive index adopts the value of being measured by Abbe refractomecer [ア go (strain) is made, ProductName " DR-M4 "].

(6) birefraction of polaroid (Δ n _XyAnd phase difference value (Δ n [1000]) _Xy* d) assay method:

Use prince's instrumentation machine (strain) manufacturing, the device of commodity " KOBRA-31X100/IR " by name at wavelength 1000nm, is measured down for 23 ℃.

(7) Determination of thickness method

During thickness less than 10 μ m, use film to make ProductName " Instantaneous Multiple Light Measuring SystemMCPD-2000 " with spectrophotometer [Da mound electronics (strain)] measure.Thickness is 10 μ m when above, and the Digit Display Micrometer " KC-351C type " of using ア Application リ Star to make is measured.

(8) assay method of polyimide based resin molecular weight:

By gel permeation chromatography (GPC) method polyethylene oxide is calculated as standard sample.Device, utensil and condition determination are as follows.

Sample: test portion is dissolved in the eluant, makes the solution of 0.1 quality %.

Pre-service: after leaving standstill 8 hours, with the membrane filter filtration of 0.45 μ m.

Analytical equipment: " the HL C-8020GPC " of eastern ソ-manufacturing.

Post: the GMH of eastern ソ-manufacturing _XL+ GMH _XL+ G2500H _XL

Column dimension: be respectively

(meter 90cm).

Eluant: dimethyl formamide (add 10mM lithium bromide and 10mM phosphoric acid and mix formation 1L dimethyl formamide solution).

Flow: 0.8ml/min..

Detecting device: RI (differential refractometer).

Column temperature: 40 ℃.

Injection rate IR: 100 μ l.

(9) assay method of contrast of LCD degree

In 23 ℃ darkroom, open backlight and through after 30 minutes, be called the device of " EZ Contrast160D " with the product of ELDIM company manufacturing, the position angle of measuring display frame is 0 °～360 °, when polar angle is 60 °, the Y value of the XYZ coloring system under display white image and the black image situation.Calculate oblique contrast (YW/YB) by the Y value (YW) of white image and the Y value (YB) of black image.Also have, it is 0 ° that the long limit of liquid crystal panel is considered as the position angle, and it is 0 ° that normal direction is considered as polar angle.

[the making example 1 of polaroid]

For thickness be 75 μ m be that [Network ラ レ (strain) makes for the non-stretched film of principal ingredient with the polyvinyl alcohol resin, trade name " VF-PS#7500 "], on one side vertically applying tension force, flood on one side at film respectively in 5 baths of following condition, is that 4.5 times degree stretches according to making final stretching ratio with respect to the former length of film.With this oriented film in 60 ℃ air circulating type drying oven dry 1 minute, make the polaroid A that thickness is 40 μ m.The monolithic transmissivity of resulting polaroid A, birefraction (the Δ n under the wavelength 1000nm _Xy) etc. measurement result be shown in table 1.

＜condition 〉

(1) expansion bath: 30 ℃ pure water, dip time 60 seconds.

(2) dye bath: 30 ℃ the aqueous solution that contains the potassium iodide of the iodine of 0.038 quality % and 0.2 quality %.Dip time 65 seconds.

(3) first crosslinked baths: 40 ℃ the aqueous solution that contains the boric acid of the potassium iodide of 3 quality % and 3 quality %.Dip time 25 seconds.

(4) second crosslinked baths: 60 ℃ the aqueous solution that contains the boric acid of the potassium iodide of 5 quality % and 4 quality %.Dip time 40 seconds.

(5) washing is bathed: 25 ℃ the aqueous solution that contains the potassium iodide of 3 quality %.Dip time 10 seconds.

Utilization is water-soluble binder (Japanese synthetic chemical industry (strain) manufacturing of principal ingredient with the polyvinyl alcohol resin, trade name " go one セ Off ア イ マ one Z2000 "), pasting thickness in the both sides of this polaroid A is the plain resinoid macromolecule membrane of fibre-bearing (Fuji's description Off イ Le system (strain) manufacturing, the trade name " UZ-TAC " of 80 μ m; Re[590]=1nm, Rth[590]=60nm), make polarization plates A.

Table 1

	Polaroid A (stretching 4.5 times)	Polaroid B (stretching 6.0 times)
			Monolithic transmissivity (%)	39.2	42.9
Parallel transmissivity (%)	30.5	36.5
			Vertical transmissivity (%)	0.0020	0.0030
Degree of polarization (%)	99.99	99.99
			Content of iodine (quality %)	4.6	2.6
Potassium content (quality %)	1.1	0.6
			The vertical transmissivity (%) of wavelength 440nm	0.006	0.023
The vertical transmissivity (%) of wavelength 550nm	0.001	0.002
			The vertical transmissivity (%) of wavelength 660nm	0.001	0.003
Birefraction (Δ n xy)	0.019	0.036
			Phase differential (Δ n in the face xy·d)	756	900
Dichroic ratio	62.2	133.6

[the making example 2 of polaroid]

In dye bath, add iodine 0.025 quality %, and be that 6.0 times degree stretches with respect to the former length of film, in addition, make polaroid B by the mode identical with the making example 1 of above-mentioned polaroid according to making final stretching ratio.Birefraction (the Δ n of the monolithic transmissivity of the polaroid B that obtains, wavelength 1000nm _Xy) etc. measurement result be shown in table 1.

By the mode identical with the making example 1 of polaroid, paste the macromolecule membrane that contains cellulosic resin in the both sides of this polaroid B, make polarization plates B.

[the making example 3 of polaroid]

The iodine concentration in improving dye bath, make polaroid C by the mode identical with the making example 1 of above-mentioned polaroid.The dichromatism of measuring resulting polaroid C is the monolithic transmissivity when, and dichroic ratio is 48.5, and the monolithic transmissivity is 36.8%.

By the mode identical with the making example 1 of polaroid, paste the macromolecule membrane that contains cellulosic resin in the both sides of this polaroid C, make polarization plates C.

[the making example 4 of polaroid]

The iodine concentration in reducing dye bath, make polaroid D by the mode identical with the making example 1 of above-mentioned polaroid.The dichromatism of the polaroid D that mensuration obtains is the monolithic transmissivity when, and dichroic ratio is 91.4, and the monolithic transmissivity is 42.9%.

By the mode identical with the making example 1 of polaroid, paste the macromolecule membrane that contains cellulosic resin in the both sides of this polaroid D, make polarization plates D.

[making of phase separation layer]

In that being installed, mechanical type stirring apparatus, DeanStark device, nitrogen ingress pipe, temperature take into account in the reaction vessel (500ml) of cooling tube, add 2,2 '-two (3,4-dicarboxyl phenyl) hexafluoro propionic acid dianhydride [Network ラ リ ア Application ト ジ ヤ パ Application (strain) manufacturing] 17.77g (40mmol) and 2, two (trifluoromethyl)-4 of 2-, 4 '-benzidine base [Wakayama refine industry (strain) manufacturing] 12.81g (40mmol).Then, interpolation is dissolved in the solution that forms among the metacresol 275.21g with isoquinoline 2.58g (20mmol).With oil bath reaction vessel is heated then, making the temperature in the reaction vessel is 180 ± 3 ℃, stirs 5 hours while being incubated, and obtains yellow solution.Stirred 3 hours again, and stopped heating and stirring then, natural cooling recovers room temperature, and then polymkeric substance forms gel and separates out.

Add acetone in the yellow solution in above-mentioned reaction vessel, above-mentioned gel is dissolved fully, make dilute solution (7 quality %).While stirring this dilute solution is little by little added in the 2L isopropyl alcohol, separate out white powder.Leach this powder, render in the isopropyl alcohol of 1.5L and wash.Repeat same operation again and wash, and then leach above-mentioned powder.Drying is after 48 hours in 60 ℃ air circulating type drying oven with it, and drying is 7 hours under 150 ℃, obtains the polyimide powder of following structural formula (III), and yield is 85%.The weight-average molecular weight of above-mentioned polyimide (Mw) is 124000, and the imidizate rate is 99.9%.

[chemical formula 3]

Above-mentioned polyimide powder is dissolved in the methyl isobutyl ketone, is mixed with the polyimide solution of 15 quality %.With the channel mould coating machine the even curtain coating of this polyimide solution is formed sheet on tri acetyl cellulose film (thick 80 μ m) surface.Then, this film is put into the air circulating type drying oven of multichamber type, the limit evaporating solvent is slowly heated up according to 80 ℃ following 2 minutes, 135 ℃ following 5 minutes, 150 ℃ following modes of 10 minutes in the limit from low temperature.Then, use the tentering drawing machine, adopt the horizontal uniaxial tension method of stiff end at 147 ℃ with this film stretching to 1.14 times.Then, peel off the tri acetyl cellulose film, obtain the polyimide layer that thickness is 3.4 μ m (phase separation layer).The birefringence spheroid of this phase separation layer shows the relation of nx＞ny＞nz, T[590]=91%, Re[590]=50nm, Rth[590]=210nm, Nz coefficient=4.2.

[preparation of liquid crystal cells]

From the commercially available liquid crystal indicator [40 inches LCD TV that Sony makes, trade name " BRAVIA KDL-40X1000 "] of the liquid crystal cells that contains the VA pattern, take off liquid crystal panel, the optical thin films such as polarization plates that liquid crystal cells disposes are up and down removed fully.Wash the surface and the back side of the glass plate of this liquid crystal cells, obtain liquid crystal cells.

[embodiment 1]

In the visual side of the liquid crystal cells of above-mentioned preparation, paste the above-mentioned phase separation layer of making by the acrylic adhesive of thick 20 μ m.This phase separation layer is to paste according to the mode of the long side direction perpendicular of slow-axis direction that makes this phase separation layer and liquid crystal cells.Then, on the surface of this phase separation layer (face of the opposition side of the face of pasting with liquid crystal cells), paste the polarization plates A that makes example 1 by the acrylic adhesive of thick 20 μ m.This polarization plates A (hereinafter referred to as first polarization plates) that is layered on this phase separation layer pastes according to the substantially parallel mode of the long side direction that makes its absorption axes direction and liquid crystal cells.Then, on an opposite side (backlight side) of the visual side of above-mentioned liquid crystal cells, paste the polarization plates A that makes example 1 by the acrylic adhesive of thick 20 μ m.The polarization plates A of an opposite side of liquid crystal cells (hereinafter referred to as second polarization plates) pastes according to the mode of the long side direction perpendicular that makes its absorption axes direction and above-mentioned liquid crystal cells.

Therefore, the absorption axes direction perpendicular of first polarization plates and second polarization plates.In addition, the absorption axes direction perpendicular of the slow-axis direction of phase separation layer and first polarization plates.

The liquid crystal panel that obtains is in such a way combined with the back light unit of the above-mentioned former liquid crystal indicator that takes off, make the liquid crystal indicator of embodiment 1.The characteristic of resulting liquid crystal indicator is shown among Fig. 1 and Fig. 3.

The contrast of this liquid crystal indicator under position angle 45 degree, polar angle 60 degree is 58.

[embodiment 2]

With making the polarization plates C that makes in the example 3, in addition, make liquid crystal panel and liquid crystal indicator according to the method identical with the foregoing description 1 as first polarization plates and second polarization plates.The contrast of this liquid crystal indicator under position angle 45 degree, polar angle 60 degree is 47.

[embodiment 3]

With making the polarization plates D that makes in the example 4, in addition, make liquid crystal panel and liquid crystal indicator according to the method identical with the foregoing description 1 as first polarization plates and second polarization plates.The contrast of this liquid crystal indicator under position angle 45 degree, polar angle 60 degree is 45.

[comparative example]

With making the polarization plates B that makes in the example 2, in addition, make liquid crystal panel and liquid crystal indicator according to the method identical with the foregoing description 1 as first polarization plates and second polarization plates.The characteristic of the liquid crystal indicator of comparative example is shown among Fig. 2 and Fig. 3.

The contrast of this liquid crystal indicator under position angle 45 degree, polar angle 60 degree is 32.

[evaluation]

By embodiment 1～3 and comparative example as can be known, the liquid crystal indicator that possesses the liquid crystal panel of each embodiment is compared with the liquid crystal indicator of the liquid crystal panel that uses comparative example, and oblique contrast is significantly increased.

Claims (14)

1. a liquid crystal panel is characterized in that, this liquid crystal panel possesses liquid crystal cells, be disposed at first polaroid of this liquid crystal cells one side and be disposed at second polaroid of this liquid crystal cells opposite side, wherein,

The polaroid of at least one side in first polaroid and second polaroid is dyeed by dichroic substance, and dichroic ratio is 40～100.

2. liquid crystal panel according to claim 1, above-mentioned at least one side's polaroid show that degree of polarization is more than 99% and the monolithic transmissivity is 35%～45% polarization characteristic.

3. according to the liquid crystal panel described in claim 1 or 2, above-mentioned at least one side's polaroid shows Δ n _XyBe 0.015～0.030 birefringence,

Wherein, Δ n _Xy=nx-ny, nx represent the refractive index of the X-direction that the face of polaroid is interior, and ny represents the refractive index of the Y direction that the face of polaroid is interior, and X-direction is the direction of the interior refractive index maximum of the face of polaroid, and Y direction is the direction vertical with this X-axis.

4. according to each described liquid crystal panel in the claim 1～3, above-mentioned at least one side's polaroid comprises the stretching polymer film that is dyeed by dichroic substance.

5. liquid crystal panel according to claim 4, the above-mentioned stretching polymer film that is dyeed by dichroic substance obtain through following operation at least: the operation that makes the hydrophilic polymer film expansion that does not stretch; The operation of the thin polymer film dyeing after will expanding with dichroic substance; Make the crosslinked operation of thin polymer film after this dyeing; Wash the operation of this thin polymer film after crosslinked; At above-mentioned expansion process to 3 times～5 times the operation that between the washing procedure thin polymer film is stretched to raw footage.

6. according to claim 4 or 5 described liquid crystal panels, above-mentioned stretching polymer film comprises the polyvinyl alcohol film, and dichroic substance comprises iodine.

7. according to each described liquid crystal panel in the claim 1～6, liquid crystal panel is of a size of more than 70 inches.

8. according to each described liquid crystal panel in the claim 1～7, above-mentioned liquid crystal cells contains the liquid crystal molecule of homeotropic alignment orientation under the state that does not have electric field.

9. according to each described liquid crystal panel in the claim 1～8, possesses phase separation layer between above-mentioned liquid crystal cells and above-mentioned first polaroid or second polaroid.

10. liquid crystal panel according to claim 9, the index ellipsoid body of above-mentioned phase separation layer demonstrates the relation of nx 〉=ny＞nz.

11. according to claim 9 or 10 described liquid crystal panels, the Nz coefficient of above-mentioned phase separation layer is 1.1～8.0.

12. according to each described liquid crystal panel in the claim 9～11, above-mentioned phase separation layer contains at least a resin that is selected from the group that polyimide based resin, polyester resin, norbornene resin and cellulosic resin form.

13. according to each described liquid crystal panel in the claim 9～12, above-mentioned phase separation layer contains polyimide based resin layer and cellulosic resin layer.

14. a liquid crystal indicator, it possesses each described liquid crystal panel in the claim 1～13.

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