CN100407001C - Lc panel and LCD device - Google Patents

Lc panel and LCD device Download PDF

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Publication number
CN100407001C
CN100407001C CN200510114266XA CN200510114266A CN100407001C CN 100407001 C CN100407001 C CN 100407001C CN 200510114266X A CN200510114266X A CN 200510114266XA CN 200510114266 A CN200510114266 A CN 200510114266A CN 100407001 C CN100407001 C CN 100407001C
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liquid crystal
film
optical element
crystal panel
polaroid
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CN1763608A (en
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小石直树
矢野周治
与田健治
林政毅
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Nitto Denko Corp
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Abstract

The present invention provides a liquid crystal panel having improved contrast ratio in an oblique direction and good display evenness without causing shift or unevenness in retardation values due to shrinkage stress of a polarizer or heat of backlight. A liquid crystal panel according to an embodiment of the present invention includes: a liquid crystal cell; a polarizer arranged on both sides of the liquid crystal cell; a first optical element arranged between one polarizer and the liquid crystal cell; and a second optical element arranged between the other polarizer and the liquid crystal cell, wherein: the first optical element comprises a retardation film containing a styrene-based resin and a polycarbonate-based resin and satisfying the following expressions (1) and (2); and the second optical element has substantially optical isotro. 240nm<=Re(590)<=350nm (1); 0.20<=Rth(590)/Re(590)<=0.80 (2).

Description

Liquid crystal panel and liquid crystal indicator
Technical field
The present invention relates to a kind of liquid crystal panel with liquid crystal cells, polaroid and optical element.In addition, the present invention relates to all use the LCD TV and the liquid crystal indicator of this liquid crystal panel.
Background technology
Be furnished with the liquid crystal indicator that switches (IPS) mode liquid crystal unit in the face and comprise by liquid crystal molecule and apply horizontal component of electric field, thereby transmittance (white shows) and light shield (black display) are controlled so that liquid crystal molecule rotates about 45 ° to substantial horizontal orientation under the situation that does not apply electric field.The problem of traditional liquid crystal indicator of being furnished with IPS mode liquid crystal unit is can variation from the contrast of the screen of watching with oblique (45 °, 135 °, 225 ° or 315 ° at the position angle) at the absorption axes angle at 45 of polaroid.
In order to address this problem, disclose and used index distribution (wherein a kind of comprising as nx＞ny＞nz, nx, ny and nz represent the refractive index of slow-axis direction, quick shaft direction and the thickness direction of film respectively) the technology (for example, JP 11-305217A) of λ/2 plates to improve oblique display performance.But disclosed technology does not provide sufficient improvement for oblique contrast and oblique gamut, therefore requires further improvement display performance.
Up to now, used the aromatic polymer membrane of for example polycarbonate resin, polyaryl thing resinoid or polyester resin as λ/2 plates (for example, JP 04-305602A or JP 05-157911A) of index distribution as nx＞ny＞nz.But the photoelastic coefficient of aromatic polymer membrane is big, and its phase difference value stress and changing easily.Therefore, the problem of aromatic polymer membrane is that show uniformity as described below descends.Under situation about being exposed to attached to the aromatic polymer membrane between liquid crystal cells and the polaroid in the high temperature, phase difference value may deviate from design load because of differential contraction stress.In addition, because the non-homogeneous stress that heat produced backlight may cause the inhomogeneous of phase difference value.
Simultaneously, for example the group aliphatic resin film of norbornene resin film has little photoelastic coefficient.Yet the group aliphatic resin film can cause phase differential hardly, the phase difference value of expectation can not as in the aromatic polymer membrane under low draw ratio, and even under high draw ratio, obtain by stretching.Under high draw ratio, stretch and to produce the problem of film fracture.In recent years, along with the increase of screen size and the raising of backlight illumination, need make further improvement to the show uniformity of liquid crystal panel.Yet aforesaid conventional art can not provide the liquid crystal panel that fully satisfies these demands.
Summary of the invention
The present invention makes for addressing the above problem, and an object of the present invention is to provide a kind of liquid crystal panel with liquid crystal cells of improved oblique contrast.Another object of the present invention provides a kind of liquid crystal panel and a kind of liquid crystal indicator, and it all has show uniformity well and not can cause phase difference value skew or uneven liquid crystal cells because of the differential contraction stress or the heat backlight of polaroid.
In order to address the above problem, the present inventor has carried out deep research, and discovery can achieve the above object by following liquid crystal panel and liquid crystal indicator, thereby has finished the present invention.
Liquid crystal panel according to one embodiment of the present invention comprises liquid crystal cells, be configured in the polaroid of liquid crystal cells both sides, be configured in first optical element between a polaroid and the liquid crystal cells and be configured in second optical element between another polaroid and the liquid crystal cells, wherein first optical element comprises and contains styrene resin and polycarbonate resin and satisfy the phase retardation film of following formula (1) and (2), and second optical element has optical isotropy basically:
240nm≤Re[590]≤350nm …(1)
0.20≤Rth[590]/Re[590]≤0.80 …(2)
In an embodiment of the invention, the absorption axes of the slow axis of first optical element and a polaroid substantially parallel and with the absorption axes perpendicular of another polaroid.
In yet another embodiment of the present invention, liquid crystal cells comprises the liquid crystal layer that contains the nematic crystal of even orientation under the situation that does not have electric field.
In yet another embodiment of the present invention, the index distribution of liquid crystal layer is nx＞ny=nz.
In yet another embodiment of the present invention, liquid crystal cells comprises a kind of in IPS pattern and the FFS pattern.
In yet another embodiment of the present invention, the initial alignment direction of liquid crystal cells is arranged essentially parallel to the absorption axes direction of the polaroid of configuration second optical element one side.
In yet another embodiment of the present invention, the initial alignment direction of liquid crystal cells is arranged essentially parallel to the absorption axes direction of the polaroid that is configured in the liquid crystal cells backlight side.
In yet another embodiment of the present invention, the initial alignment direction of liquid crystal cells is substantially perpendicular to the absorption axes direction of the polaroid that is configured in the liquid crystal cells backlight side.
In yet another embodiment of the present invention, the wavelength dispersion of first optical element is 0.81 to 1.10.
In yet another embodiment of the present invention, first optical element comprises the individual layer phase retardation film that contains styrene resin and polycarbonate resin.
In yet another embodiment of the present invention, first optical element comprises the laminate that comprises the phase retardation film that contains styrene resin and polycarbonate resin.
In yet another embodiment of the present invention, during as 100 weight portions, the content of styrene resin is 10 to 40 weight portions in the phase retardation film with total solids content.
In yet another embodiment of the present invention, the polycarbonate resin in the phase retardation film contains the repetitive by formula (5) and (6) representative.
Figure C20051011426600071
In yet another embodiment of the present invention, down to use wavelength at 23 ℃ be 2.0 * 10 as the photo measure of 590nm to the absolute value of the photoelastic coefficient of phase retardation film -11To 8.0 * 10 -11m 2/ N.
In yet another embodiment of the present invention, second optical element satisfies following formula (3) and (4):
0nm≤Re[590]≤10nm …(3)
0nm≤Rth[590]≤20nm …(4)。
In yet another embodiment of the present invention, second optical element comprises and at least aly is selected from cellulosic resin, norbornene resin and contains isobutylene and the alternating copolymer of N-methyl maleimide and the polymer film of vinyl cyanide/styrol copolymer.
In yet another embodiment of the present invention, second optical element comprises by negative electrode C plate that satisfies following formula (7) and (8) and the positive C plate that satisfies following formula (9) and (10) are carried out the laminated film that lamination prepares:
0nm≤Re[590]≤10nm …(7)
20nm≤Rth[590]≤400nm …(8)
0nm≤Re[590]≤10nm …(9)
-400nm≤Rth[590]≤-20nm?…(10)。
In yet another embodiment of the present invention, liquid crystal panel further comprises diaphragm in the outside of each polaroid.
According to a further aspect in the invention, provide a kind of LCD TV.This LCD TV comprises above-mentioned liquid crystal panel.
According to a further aspect in the invention, provide a kind of liquid crystal indicator.This liquid crystal indicator comprises above-mentioned liquid crystal panel.
Liquid crystal panel provided by the present invention is furnished with and satisfies following expression formula (1) and (2) and be configured in first optical element between a polaroid and the liquid crystal cells and have optical isotropy basically and be configured in second optical element between another polaroid and the liquid crystal cells, thereby has increased the oblique contrast of liquid crystal indicator.The photoelastic coefficient of first optical element of the present invention that comprises the phase retardation film that contains styrene resin and polycarbonate resin is little, thereby has prevented because the polaroid differential contraction stress of liquid crystal panel or the phase difference value that heat caused backlight inhomogeneous.Also do not obtain the phase retardation film that photoelastic coefficient is little and have nx＞nz＞ny relation up to now.But, in the present invention, to have the one or both sides of the shrinkability film of predetermined shrinkage ratio attached to the polymer film that contains styrene resin and polycarbonate resin, then products therefrom is carried out hot-stretch, thereby the phase retardation film that the photoelastic coefficient that satisfies following expression formula (1) and (2) is little and have the relation of nx＞nz＞ny is provided.The good visual performance that therefore can keep liquid crystal indicator for a long time.
240nm≤Re[590]≤350nm …(1)
0.20≤Rth[590]/Re[590]≤0.80 …(2)
(in expression formula (1) and (2), Re[590] and Rth[590] represent respectively 23 ℃ use down wavelength as the face of the film of the photo measure of 590nm in the phase difference value of phase difference value and thickness direction.)
Description of drawings
In the accompanying drawings:
Fig. 1 is the schematic cross-section according to the liquid crystal panel of preferred implementation of the present invention;
Fig. 2 A is the perspective diagram of liquid crystal panel shown in Figure 1, and Fig. 2 B is the perspective diagram of the liquid crystal panel of another preferred implementation according to the present invention;
Each has illustrated the perspective diagram of the typical preferred embodiment of first optical element used in the present invention to Fig. 3 A naturally to 3H, comprises the relation of itself and polaroid absorption axes;
Fig. 4 is the synoptic diagram of notion that has shown the typical preparation method of phase retardation film used in the present invention;
Each has illustrated the perspective diagram of the typical preferred embodiment of second optical element used in the present invention naturally Fig. 5 A and 5B;
Fig. 6 is the schematic cross-section according to the liquid crystal indicator of preferred implementation of the present invention;
Fig. 7 is the photo that has shown according to the demonstration unevenness measurement result of the liquid crystal cells of embodiments of the invention 1; And
Fig. 8 is the photo that has shown according to the demonstration unevenness measurement result of comparative example 5 liquid crystal cells.
Embodiment
A. the profile of whole liquid crystal panel
Fig. 1 is the schematic cross-section according to the liquid crystal panel of preferred implementation of the present invention.Fig. 2 A is the perspective diagram of O-mode liquid crystal panel, and Fig. 2 B is the perspective diagram of the liquid crystal panel of E-pattern.Notice that for clarity sake, the length and width of each member is different with actual components with high ratio among Fig. 1,2A and the 2B.Liquid crystal panel 100 is furnished with liquid crystal cells 10, is configured in the polaroid 20 and 20 of liquid crystal cells 10 both sides ', be configured in first optical element 30 between a polaroid (being polaroid 20 among Fig. 1,2A and the 2B) and the liquid crystal cells 10 and be configured in second optical element 40 between another polaroid (among Fig. 1,2A and the 2B for polaroid 20 ') and the liquid crystal cells 10.In actual applications, can polaroid 20 and 20 ' the diaphragm (not shown) that is fit to arbitrarily of outside configuration.The slow axis (during detection) that Fig. 1,2A and 2B have shown parallel to each other and second optical element 40 of the absorption axes of the slow axis of first optical element 30 and polaroid 20 and polaroid 20 ' absorption axes situation parallel to each other.But the absorption axes of the slow axis of first optical element 30 and polaroid 20 can be orthogonal, and the slow axis of second optical element 40 (during detection) and polaroid 20 ' absorption axes can be orthogonal.First optical element comprises and contains styrene resin and polycarbonate resin and satisfy the phase retardation film of following formula (1) and (2), and second optical element has optical isotropy basically.
240nm≤Re[590]≤350nm …(1)
0.20≤Rth[590]/Re[590]≤0.80 …(2)
(in expression formula (1) and (2), Re[590] and Rth[590] represent respectively 23 ℃ use down wavelength as the face of the film of the photo measure of 590nm in the phase difference value of phase difference value and thickness direction.
Preferably with polaroid 20 ' be configured to make its absorption axes to be arranged essentially parallel to the initial alignment direction of liquid crystal cells 10.Preferably polaroid 20 is configured to make its absorption axes be substantially perpendicular to the initial alignment direction of liquid crystal cells 10.
Liquid crystal panel of the present invention can be an E-pattern so-called O-pattern or so-called.Term " liquid crystal panel of O-pattern " refers to the absorption axes of the polaroid that wherein is configured in the liquid crystal cells backlight side and the initial alignment direction liquid crystal panel parallel to each other of liquid crystal cells.Term " liquid crystal panel of E-pattern " refers to the liquid crystal panel that the absorption axes of the polaroid that wherein is configured in the liquid crystal cells backlight side is perpendicular to one another with the initial alignment direction of liquid crystal cells.Shown in Fig. 2 A, in the liquid crystal panel of O-pattern, polaroid 20 and first optical element, 30 preferred disposition are in the side of watching of liquid crystal cells 10, and second optical element 40 and polaroid 20 ' preferred disposition are in the backlight side of liquid crystal cells 10.Shown in Fig. 2 B, in the liquid crystal panel of E-pattern, polaroid 20 and first optical element, 30 preferred disposition are in the backlight side of liquid crystal panel 10, and second optical element 40 and polaroid 20 ' preferred disposition are in the side of watching of liquid crystal cells 10.In the present invention, the preferred liquid crystal panel of the O-pattern shown in Fig. 2 A is because the configuration of O-pattern can realize better optical compensation.Specifically, in the configuration of O-pattern, first optical element that comprises phase retardation film is configured in away from a side backlight, therefore can be subjected to hardly because hot caused negative effect backlight shows uneven liquid crystal indicator thereby provide to exist hardly.Hereinafter, specifying according to the assembly of liquid crystal panel of the present invention will be provided.
B. liquid crystal cells
With reference to figure 1, the employed liquid crystal cells 10 of liquid crystal panel of the present invention be furnished with a pair of substrate 11 and 11 and be configured in substrate 11 and 11 ' between as the liquid crystal layer 12 of display medium.A substrate (colored filter substrate) 11 is furnished with colored filter and black matrix" (all not showing).The on-off element that another substrate (active-matrix substrate) 11 ' be furnished with is used to control the liquid crystal electrooptical performance (be generally TFT, show), be used to on-off element that the sweep trace (not shown) of gate signal is provided and be used to its signal wire (not shown) that source signal is provided and pixel electrode and electrode (counter electrode) (all showing).Colored filter also can be configured in active-matrix substrate 11 ' in.Substrate 11 and 11 ' between distance (cell gap) controlled by separator (spacer) (not shown).By the formed alignment film (not shown) of for example polyimide be configured in liquid crystal layer 12 contacted each substrate 11 and 11 ' a side.
Preferred liquid crystal layer 12 contains the nematic crystal of even orientation under the situation that does not have electric field.The index distribution of this liquid crystal layer (finally becoming liquid crystal cells) is generally nx＞ny=nz (wherein, nx, ny and nz represent the refractive index of film at slow-axis direction, quick shaft direction and thickness direction respectively).In instructions of the present invention, ny=nz not only comprises the situation that ny and nz equate fully, also comprises the situation that ny and nz equate basically.In addition, phrase " the initial alignment direction of the liquid crystal cells " orientation that refers to the nematic crystal in the liquid crystal layer under the situation that does not have electric field provides the direction of refractive index in the largest face of liquid crystal layer.The exemplary of drive pattern that use demonstrates the liquid crystal layer of such index distribution comprises switches (IPS) pattern in the face and fringing field switches (FFS) pattern.
In the IPS pattern, the nematic crystal that does not have under the situation of electric field evenly orientation for example by use electrically conerolled birefringence (ECB) effect each free metal formation to electrode and pixel electrode between respond in the electric field that is parallel to substrate (being also referred to as horizontal component of electric field) that produces.Specifically, as " Monthly Display July (display monthly magazine July number) " (the 83rd to 88 page, Techno Times company publishes, 1997) or " Ekisho (liquid crystal) vol.2; No.4 " (the 303rd to 316 page, Japanese Liquid Crystal Society (Japanese liquid crystal association) publishes, 1998) described, normal black mode is not having to provide black display completely under the situation of electric field in the following manner: the absorption axes that makes the alignment direction of liquid crystal cells and a polaroid under the situation that does not apply electric field in the same way and make Polarizer in the liquid crystal cells configuration that is perpendicular to one another up and down.Applying under the situation of electric field, it is parallel with substrate that the liquid crystal molecule rotation keeps simultaneously, thereby obtain transmissivity according to rotation angle.The IPS pattern comprises switching in the super face that uses V-shape electrode, Z-shaped electrode etc. switches (AS-IPS) pattern in (S-IPS) pattern and the senior super face.The example of commercially available IPS mode LCD comprises 20 inches wide LCD TV " Wooo " (trade name, Hitachi, Ltd. (Hitachi, Ltd.) manufacturing), 19 inches LCD " ProLite E481S-1 " (trade name, Iiyama Corporation (meal mountain Co., Ltd.) makes) and 17 inches TFT LCD " FlexScan L565 " (trade name, Eizo NanaoCorporation (tall and erect Co., Ltd. plants) makes).
In the FFS pattern, under the situation that does not have electric field evenly the nematic crystal of orientation for example by use electrically conerolled birefringence (ECB) effect each free transparent conductor formation to electrode and pixel electrode between produce be parallel in the electric field (being also referred to as horizontal component of electric field) to electrode base board and respond.Horizontal component of electric field in this FFS pattern is also referred to as fringe field, its can by each free transparent conductor is formed to the distance setting between electrode and the pixel electrode for producing than cell gap is narrow.Specifically, as described in " Society for Information Display (SID) (international information show association) 2001 Digest " (the 484th to 487 page) or JP2002-031812A, normal black mode is providing black display completely in the following manner under the situation that does not have electric field: the absorption axes that makes the alignment direction of liquid crystal cells and a polaroid under the situation that does not apply electric field in the same way and make Polarizer in the liquid crystal cells configuration that is perpendicular to one another up and down.Applying under the situation of electric field, it is parallel with substrate that the liquid crystal molecule rotation keeps simultaneously, thereby obtain transmissivity according to rotation angle.The FFS pattern comprises that the senior fringing field that uses V-arrangement electrode, Z-shaped electrode etc. switches (A-FFS) pattern or super fringing field switches (U-FFS) pattern.The example of commercially available FFS mode LCD comprises Tablet PC " M1400 " (trade name, Motion Computing company makes).
By substrate that has carried out the orientation processing and the nematic crystal molecule that the interaction between the nematic crystal molecule obtains even orientation, wherein the orientation vector of nematic crystal molecule is parallel to base plan and evenly orientation.In instructions of the present invention, evenly orientation comprises the situation of orientation vector with respect to the real estate slight inclination, that is, and and the situation of nematic crystal molecule pre-tilt.In the situation of nematic crystal pre-tilt, preferred pre-tilt angle is 20 ° or littler of to keep big contrast and to obtain good display performance.
Can use the nematic crystal that is fit to arbitrarily as nematic crystal according to purpose.Nematic crystal can have positive dielectric anisotropy or negative dielectric anisotropic.Object lesson with nematic crystal of positive dielectric anisotropy comprises " ZLI-4535 " (trade name, Japanese Merck (Merck) company makes).Object lesson with nematic crystal of negative dielectric anisotropic comprises " ZLI-2806 " (trade name, Japanese Merck (Merck) company makes).Can suitably set difference between ordinary refraction index (no) and the extraordinary ray refractive index (ne) according to the speed of response of liquid crystal, transmissivity etc., that is, and birefraction (Δ n LC).But usually preferred birefraction is 0.05 to 0.30.
Can use the cell gap (distance substrate between) of suitable arbitrarily cell gap according to purpose as liquid crystal cells.But the preferred cell gap is 1.0 to 7.0 μ m.Cell gap can reduce the response time and good display performance is provided in above scope.
C. polaroid
Can use the polaroid that is fit to arbitrarily as polaroid used in the present invention according to purpose.Its example comprises by the dichroic substance of adsorbing iodine for example or dichroic dye on the hydrophilic polymer membrane of polyvinyl alcohol film for example, the formalized polyvinyl alcohol film of part or partly-hydrolysed ethylene/vinyl acetate copolymer class film and this film is carried out the polyenoid based oriented film of the dechlorination product of the dehydration product of film that uniaxial tension prepares and for example polyvinyl alcohol film or polyvinyl chloride film.Wherein, because its high polarization dichromatism, the especially preferred dichroic substance by on the polyvinyl alcohol film, adsorbing iodine for example and this film carried out the film that uniaxial tension prepares.The thickness of polaroid is not particularly limited, but is generally 5 to 80 μ m.The polaroid that is configured in the liquid crystal cells both sides can be same to each other or different to each other.
By absorption iodine on the polyvinyl alcohol film and this film is carried out the polaroid that uniaxial tension prepares to be prepared by for example following method: the polyvinyl alcohol film is immersed in the aqueous solution of iodine to dye, then this film is stretched to 3 to 7 times length of initial length.This aqueous solution can contain boric acid, zinc sulfate, zinc chloride etc. as required, perhaps this polyvinyl alcohol film can be immersed in the aqueous solution of potassium iodide etc.In addition, can before dyeing, will clean in this polyvinyl alcohol film immersion water as required.
Water cleans this polyvinyl alcohol film not only can remove the pollutant or the flush away detackifier on striping surface, and the effect that prevents inhomogeneous (for example uneven dyeing that causes by the expansion of this polyvinyl alcohol film), for example uneven dyeing of expanding and causing are provided by the polyvinyl alcohol film.To the stretching of this film can be before film being dyeed with iodine, carry out afterwards or simultaneously.Stretching can be carried out in the aqueous solution of boric acid or potassium iodide or carry out in water-bath.
D. first optical element
With reference to figure 1,2A and 2B, first optical element 30 is configured between liquid crystal cells 10 and the polaroid 20.First optical element 30 comprises and contains styrene resin and polycarbonate resin and satisfy the phase retardation film of following formula (1) and (2).
240nm≤Re[590]≤350nm …(1)
0.20≤Rth[590]/Re[590]≤0.80?…(2)
D-1. the optical property of first optical element
In instructions of the present invention, Re[590] to refer under 23 ℃ by wavelength be phase difference value in the face of photo measure of 590nm.Re[590] can be from equation Re[590]=(nx-ny) * d determines (wherein, nx and ny represent the refractive index of film slow-axis direction and quick shaft direction under the wavelength of 590nm respectively, and d (nm) represents the thickness of film).Notice that slow axis refers to the direction that refractive index in the largest face is provided.
The Re[590 of first optical element] be 240 to 350nm, preferred 240 to 300nm, more preferably 260 arrive 280nm, preferred especially 265 to 275nm.With Re[590] be adjusted to and measure about 1/2 of wavelength, thus increased the oblique contrast of liquid crystal indicator.
In instructions of the present invention, Rth[590] to refer under 23 ℃ by wavelength be the thickness direction phase difference value of the photo measure of 590nm.Rth[590] can be from equation Rth[590]=(nx-nz) * d determines (wherein, nx and nz represent the refractive index of film slow-axis direction and thickness direction under the wavelength of 590nm respectively, and d (nm) represents the thickness of film).Notice that slow axis refers to the direction that refractive index in the largest face is provided.
The Rth[590 of preferred first optical element] be 35 to 190nm, more preferably 90 to 190nm, preferred especially 100 arrive 165nm, most preferably 120 arrive 155nm.
Re[590] and Rth[590] can use " KOBRA-21ADH " (trade name, OjiScientific Instruments (prince's scientific instrument Co., Ltd.) makes) to measure.Refractive index n x, ny and nz can measure in the following manner: use 23 ℃ uses down wavelength as the face of the measured film of the light of 590nm in phase difference value (Re), by 40 ° of mean refractive indexs (n0) that slow axis is tilted as thickness (d) and the phase retardation film of the measured phase difference value in pitch angle (R40), phase retardation film, the following equation of use (i) is to (vi) to carry out evaluation calculating then.Then, can (iv) calculate Rth by following equation.Here, Φ and ny ' are respectively in order to descend equation (v) with (vi) representative.
Re＝(nx-ny)×d …(i)
R40＝(nx-ny′)×d/cos(Φ) …(ii)
(nx+ny+nz)/3＝n0 …(iii)
Rth＝(nx-nz)×d …(iv)
Φ＝sin -1[sin(40°)/n0] …(v)
ny′＝ny×nz[ny 2×sin 2(Φ)+nz 2×cos 2(Φ)] 1/2?…(vi)
In instructions of the present invention, Rth[590]/Re[590] refer to 23 ℃ use down wavelength as the phase difference value of the thickness direction of the photo measure of 590nm and face in the ratio of phase difference value.
The Rth[590 of preferred first optical element]/Re[590] for being 0.2 to 0.8, more preferably 0.2 to 0.7, further preferred 0.2 to 0.6, preferred especially 0.4 to 0.6, most preferably 0.45 to 0.55.The Rth[590 of phase retardation film]/Re[590] 0.5 phase difference value that can provide with the irrelevant substantial constant of angle is provided, and can increase the oblique contrast of liquid crystal indicator.
The wavelength dispersion of preferred first optical element is 0.81 to 1.10, preferred especially 0.95 to 1.05.Less wavelength dispersion provides the constant phase difference in the wide zone of visible light in the above-mentioned scope.Therefore the oblique contrast of liquid crystal indicator can be increased, and oblique gamut can be reduced.Notice that the wavelength dispersion of phase retardation film is commonly referred to as the wavelength dependency of phase difference value.Wavelength dispersion can by 23 ℃ use down wavelength as the face of the photo measure of 480nm and 590nm in the ratio Re[480 of phase difference value Re]/Re[590] represent.Note Re[480] and Re[590] represent respectively 23 ℃ use down wavelength as the face of the photo measure of 480nm and 590nm in phase difference value.
D-2. dispose the mode of first optical element
Can use the method that is fit to arbitrarily as the method that first optical element 30 is configured between liquid crystal cells 10 and the polaroid 20 according to purpose.Preferably by the both sides at first optical element 30 provide bonding coat or pressure-sensitive adhesive layer (not shown) with first optical element 30 attached on polaroid 20 and the liquid crystal cells 10.Can increase the contrast of LCD degree that adopts first optical element 30 thus.
Can suitably set the thickness of bonding or pressure-sensitive adhesive layer according to the purposes of expecting, bond strength etc.Yet its thickness is generally 1 to 500 μ m, preferred 5 to 200 μ m, preferred especially 10 to 100 μ m.
Can use the bonding agent or the contact adhesive that are fit to arbitrarily to form bonding coat or pressure-sensitive adhesive layer.Its example comprises the polymkeric substance that contains for example acrylate copolymer, polysiloxane base polymer, polyester, polycarbamate, polyamide, polyvinylether, vinyl acetate/vinyl chloride copolymer, improved polyalkene, epoxide polymer, fluorine-based polymer or rubber polymer (for example natural rubber base polymer or synthetic rubber base polymer) separately as those of base polymer, more than listed polymkeric substance can suitably select and use.Especially, from the optical clarity of excellence, the bond property that comprises appropriate wettability, cohesiveness (cohesiveness) and cohesive (adhesiveness) and excellent against weather and stable on heating angle, preferably use acrylic pressure-sensitive adhesive.
Preferred first optical element 30 disposes like this: make its slow axis substantially parallel or perpendicular to the absorption axes of the polaroid 20 of adjacency.More preferably first optical element 30 disposes like this: make its slow axis be arranged essentially parallel to the absorption axes of the polaroid 20 of adjacency, thereby allow the roll-type preparation of film and the adhesion of promotion film.Can significantly improve preparation efficiency thus.In instructions of the present invention, phrase " substantially parallel " comprises that the absorption axes of the slow axis of first optical element 30 and polaroid 20 becomes the situation of 0 ° ± 2.0 ° angle, preferred 0 ° ± 1.0 °, more preferably 0 ° ± 0.5 °.In instructions of the present invention, phrase " perpendicular " comprises that the absorption axes of the slow axis of first optical element 30 and polaroid 20 becomes the situation of 90 ° ± 2.0 ° angle, preferred 90 ° ± 1.0 °, more preferably 90 ° ± 0.5 °.Angle greatly departs from the degree of polarization that above-mentioned scope may cause Polarizer and descends and decrease of contrast when first optical element is used for liquid crystal indicator.
D-3. the structure of first optical element
The structure of first optical element (laminated structure) is not particularly limited, as long as first optical element comprises the phase retardation film that contains styrene resin and polycarbonate resin, and first optical element satisfies the described optical property of above-mentioned D-1 part.Specifically, first optical element can be the individual layer phase retardation film that contains styrene resin and polycarbonate resin, the laminate of two or more phase retardation films or the laminate of phase retardation film and other film (preferred isotropic membrane).Preferred first optical element is the individual layer phase retardation film so that reduce because the skew of the differential contraction stress of polaroid or the phase difference value that heat caused backlight or inhomogeneous and reduce the thickness of liquid crystal panel.First optical element as laminate can comprise bonding coat, pressure-sensitive adhesive layer etc.Comprise under the situation of two or more phase retardation films and/or two or more other films that at first optical element each phase retardation film and/or other film can be same to each other or different to each other as laminate.Below will describe polycarbonate resin, styrene resin and other film in detail.
Can suitably select Re[590 according to the number of the phase retardation film that will use] as the phase retardation film of first optical element.For example, first optical element by the film formed situation of individual layer phase differential under, the Re[590 of preferred phase retardation film] equal the Re[590 of first optical element].Therefore, be preferred for the phase differential of pressure-sensitive adhesive layer, bonding coat or the analog of the first optical element lamination on polaroid or liquid crystal cells as much as possible little.In addition, be to comprise under the situation of laminate of two or more phase retardation films total Re[590 of preferred phase retardation film at first optical element] be designed to equal the Re[590 of first optical element].Specifically, using under the situation of two phase retardation films, preferably use Re[590] 100 to 175nm the phase retardation film of respectively doing for oneself.In addition, the slow axis of preferred two phase retardation films lamination of carrying out parallel to each other.
No matter the quantity of employed phase retardation film, the Rth[590 of preferred phase retardation film]/Re[590] equal the Rth[590 of first optical element]/Re[590].For example, can be by to Rth[590]/Re[590] respectively do for oneself 0.5 and Re[590] thereby obtain Rth[590 for two phase retardation films of 140nm carry out lamination in the mode parallel to each other of slow axis separately]/Re[590] be 0.5 Re[590] be the optical element of 280nm.
The gross thickness of preferred first optical element is 10 to 200 μ m, more preferably 15 to 150 μ m, preferred especially 40 to 100 μ m, most preferably 50 to 80 μ m.First optical element has the thickness in the above-mentioned scope, thereby the liquid crystal indicator with excellent optical homogeneity is provided.
Fig. 3 A is to respectively the do for oneself perspective diagram of typical preferred embodiment of explanation first optical element used in the present invention of 3H, comprises the relation of itself and polaroid absorption axes.Fig. 3 A is to having shown separately that with 3B first optical element 30 is the situation of individual layer phase retardation film.Fig. 3 A has shown that 30 slow axis is parallel to the situation of the absorption axes of polaroid 20 to phase retardation film (first optical element), and Fig. 3 B has shown the situation of the slow axis of phase retardation film (first optical element) 30 perpendicular to the absorption axes of polaroid 20.In this embodiment, phase retardation film also serves as the diaphragm of the polaroid on liquid crystal cells one side, thereby helps to reduce the thickness of liquid crystal cells.In addition, from making because the skew of the differential contraction stress of polaroid or the phase difference value that heat caused backlight or the angle of the inhomogeneous effect that reduces are considered preferred these embodiments.Fig. 3 C and 3D have shown that separately first optical element 30 is situations of the laminate an of phase retardation film 31 and other film (preferred isotropic membrane) 36.Fig. 3 C has shown that the slow axis of phase retardation film 31 is parallel to the situation of the absorption axes of polaroid 20, and Fig. 3 D has shown the situation of the slow axis of phase retardation film 31 perpendicular to the absorption axes of polaroid 20.Preferably another film 36 is configured in a side of polaroid 20.In this embodiment, this other film serves as the diaphragm of the polaroid on liquid crystal cells one side.Can use isotropic membrane as other film, thereby the Rth that eliminates traditional diaphragm is to harmful effect that Polarizer caused.Fig. 3 E and 3F have shown that separately first optical element 30 is situations of the laminate of two phase retardation films 31 and 32, and Fig. 3 G and 3H have shown that separately first optical element 30 is two phase retardation films 31 and 32 and the situation of the laminate of another film 36.As mentioned above, phase retardation film 31 and 32 Re[590] be designed to make total Re[590 separately] equal the Re[590 of first optical element], and its Rth[590]/Re[590] be designed to equal the Rth[590 of first optical element separately]/Re[590].For for simplicity, illustrated that first optical element 30 comprises the situation of maximum two phase retardation films and maximum other films.But the present invention obviously can be applied to have separately the laminate of three or more phase retardation films and/or two or more other films.
D-4. the phase retardation film that contains styrene resin and polycarbonate resin
As mentioned above, first optical element used in the present invention comprises the phase retardation film that contains styrene resin and polycarbonate resin (may be called styrene/polycarbonate admixture hereinafter).This phase retardation film is the stretching polymer film that contains styrene resin and polycarbonate resin.The preferred employed polymer film that contains styrene resin and polycarbonate resin has little photoelastic coefficient and causes phase differential easily.In this phase retardation film, styrene resin is used to reduce photoelastic coefficient.
The photoelastic coefficient of phase retardation film is often referred to when apply external pressure on blooming and causes birefringent easiness when causing internal stress.The absolute value of preferred phase retardation film photoelastic coefficient is little, thereby excellent optical homogeneity is provided and suppresses because distortion waits the inhomogeneous of the phase differential that caused.Can measure photoelastic coefficient in the following manner: use elliptic polarization spectrometer " M-220 " (trade name, JASCO Corporation (Japanese beam split Co., Ltd.) makes), phase difference value in 23 ℃ of faces that use down wavelength measures 2cm * 10cm under stress as the light of 590nm sample is then from the slope calculating photoelastic coefficient of the function of phase difference value and stress.
Preferably use the photoelastic coefficient C[590 of wavelength down as the phase retardation film of the photo measure of 590nm at 23 ℃] (m 2/ N) absolute value is 2.0 * 10 -11To 8.0 * 10 -11, more preferably 2.0 * 10 -11To 6.0 * 10 -11, preferred especially 3.0 * 10 -11To 6.0 * 10 -11, most preferably 4.0 * 10 -11To 6.0 * 10 -11Photoelastic coefficient can provide in above-mentioned scope and can cause hardly because the skew or the phase retardation film inhomogeneous and that have nx＞nz＞ny relation of the differential contraction stress of polaroid or hot caused phase difference value backlight.Under the situation of using the individual layer phase retardation film, with the photoelastic coefficient absolute value of this phase retardation film photoelastic coefficient absolute value as first optical element.Use such phase retardation film, thereby significantly improve the oblique demonstration unevenness of liquid crystal indicator.
Whether the thickness of phase retardation film can change with the quantity of the phase retardation film of institute's lamination and the existence of other film.The gross thickness of preferred first optical element that is obtained can be set at 10 to 200 μ m, more preferably 15 to 150 μ m, preferred especially 40 to 100 μ m, most preferably 50 to 80 μ m.For example, first optical element be by the film formed situation of individual layer phase differential under, the thickness of preferred phase retardation film is 10 to 200 μ m (that is, equaling the gross thickness of first optical element).In addition, for example, be that each phase retardation film can have the thickness that is fit to arbitrarily, as long as the gross thickness of phase retardation film equals the preferred first optical element gross thickness under the situation of laminate of two phase retardation films at first optical element.Therefore, the thickness of phase retardation film can be same to each other or different to each other.Two phase retardation films are being carried out in the embodiment of lamination, and the thickness of a preferred phase retardation film is 5 to 100 μ m, and preferably the thickness of another phase retardation film is 50 to 100 μ m.
During as 100 weight portions, the content of styrene resin is 10 to 40 weight portions in optimization styrene/polycarbonate admixture with total solids content, more preferably 20 to 40 weight portions, preferred especially 22 to 38 weight portions, most preferably 25 to 35 weight portions.The content of styrene resin can fully reduce the photoelastic coefficient of phase retardation film in above-mentioned scope, and can guarantee to conform with the glass transition temperature (being also referred to as Tg) or the rigidity of permanance, self-supporting performance, tensile property etc.Therefore, can obtain even liquid crystal indicator also can cause hardly because the skew of the phase difference value that causes of stress or phase retardation film inhomogeneous and that have nx＞nz＞ny relation when it is used for.
Can be by the phase retardation film that contains styrene resin and polycarbonate resin be carried out the content that gpc measurement is measured styrene resin.Specifically, phase retardation film is dissolved in the tetrahydrofuran, thereby the solution of preparation 0.1wt% leaves standstill them 8 hours.Subsequently, this solution is filtered, use gel permeation chromatograph (GPC) method that filtrate is measured then with the membrane filter of 0.45 μ m.The differential molecular weight distribution curve of gained can be lower-molecular-weight component and high molecular weight component in peak-to-peak trough punishment.Can measure the content of styrene resin by expression formula [total peak area of lower-molecular-weight component/(total peak area of the total peak area+high molecular weight component of lower-molecular-weight component)] * 100.
Styrene resin refers to the styrenic polymer that the styrene monomer polymerization is obtained by the method that is fit to arbitrarily.The object lesson of styrene monomer comprises styrene, α-Jia Jibenyixi and 2,4-dimethyl styrene.In addition, can use commercially available styrene resin etc.Its object lesson comprises styrene resin, vinyl cyanide/styrene resin, acrylonitrile/butadiene/styrene resin, vinyl cyanide/ethylene/styrene resin, styrene/maleimide copolymer and styrene/maleic anhydride copolymers.Such monomer or resin can use or unite use separately.In addition, styrene resin and styrene monomer can be united use.
It is preferred that to use tetrahydrofuran to be converted into polystyrene as the weight-average molecular weight (Mw) of launching the styrene resin that solvent measures by the GPC method be less than 20,000, more preferably 1,000 to 10,000, preferred especially 1,000 to 6,000, most preferably 1,000 to 3,000.The styrene resin of weight-average molecular weight in above-mentioned scope can evenly mix with polycarbonate resin, thereby the film of highly transparent is provided.
The preferred polycarbonate resin that uses the aromatic copolycarbonate conduct of forming by aromatic dicarboxylic phenol component and carbonic acid component to be used to contain the phase retardation film of styrene resin and polycarbonate resin.Usually can obtain aromatic copolycarbonate by the reaction between aromatic dicarboxylic phenolic compounds and the carbonic acid precursor.That is to say, can obtain aromatic copolycarbonate by the following method: phosgenation wherein is blown into phosgene in the aromatic dicarboxylic phenolic compounds in the presence of caustic alkali and solvent; Perhaps ester-interchange method wherein in the presence of catalyzer, makes aromatic dicarboxylic phenolic compounds and diaryl carbonate carry out transesterification.The object lesson of carbonic acid precursor comprises two pairs of toluene salt of bischloroformate, diphenyl carbonate, carbonic acid, carbonic acid phenyltoluene base ester (phenyl-p-tolyl carbonate), two pairs of chlorobenzene esters of carbonic acid and the carbonic acid dinaphthyl ester of phosgene, dihydric phenol.Wherein, preferred phosgene and diphenyl carbonate.
Comprise 2 with the object lesson of the aromatic dicarboxylic phenolic compounds of carbonic acid precursors reaction, two (4-hydroxyphenyl) propane, 2 of 2-, two (the 4-hydroxyls-3 of 2-, the 5-xylyl) propane, two (4-hydroxyphenyl) methane, 1, two (4-hydroxyphenyl) ethane, 2 of 1-, two (4-hydroxyphenyl) butane, 2 of 2-, two (the 4-hydroxyls-3 of 2-, the 5-xylyl) butane, 2, two (4-hydroxyl-3, the 5-two propyl phenyls) propane, 1 of 2-, two (4-hydroxyphenyl) cyclohexanes and 1 of 1-, two (the 4-hydroxyphenyl)-3,3 of 1-, the 5-trimethyl-cyclohexane.The aromatic dicarboxylic phenolic compounds can use or unite use separately.Its preferred example comprises 2, two (4-hydroxyphenyl) propane, 1 of 2-, two (4-hydroxyphenyl) cyclohexanes and 1 of 1-, two (the 4-hydroxyphenyl)-3,3 of 1-, 5-trimethyl-cyclohexane.Preferred especially 2, two (4-hydroxyphenyl) propane and 1 of 2-, two (the 4-hydroxyphenyl)-3,3 of 1-, the 5-trimethyl-cyclohexane is united use, has enough little photoelastic coefficient and the suitable Tg and the phase retardation film of rigidity thereby provide.
Unite and use 2, two (4-hydroxyphenyl) propane and 1 of 2-, two (the 4-hydroxyphenyl)-3,3 of 1-, the 5-trimethyl-cyclohexane contains by the repetitive with following formula (5) and (6) representative as the polycarbonate resin of aromatic dicarboxylic phenolic compounds.
Figure C20051011426600211
In formula (5) and (6), n represents 2 or bigger integer.
Uniting use 2, two (4-hydroxyphenyl) propane and 1 of 2-, two (the 4-hydroxyphenyl)-3 of 1-, 3, under the situation of 5-trimethyl-cyclohexane as aromatic dicarboxylic phenol, can be by changing employed 2, two (4-hydroxyphenyl) propane and 1 of 2-, two (the 4-hydroxyphenyl)-3,3 of 1-, the ratio of 5-trimethyl-cyclohexane is regulated the Tg or the photoelastic coefficient of phase retardation film.For example, in the polycarbonate resin 1, two (the 4-hydroxyphenyl)-3,3 of 1-, the content height of 5-3-methyl cyclohexanol alkanamine can make Tg raise and photoelastic coefficient is reduced.In the optimization polycarbonate resinoid 2, two (4-hydroxyphenyl) propane and 1 of 2-, 1-pair of (4-hydroxyphenyl)-3,3, the weight ratio of 5-trimethyl-cyclohexane is 2: 8 to 8: 2, more preferably 3: 7 to 6: 4, preferred especially 3: 7 to 5: 5, most preferably 4: 6.Unite use and have 2 of above weight ratio, two (4-hydroxyphenyl) propane and 1 of 2-, two (the 4-hydroxyphenyl)-3,3 of 1-, the 5-trimethyl-cyclohexane can provide the Tg of permanance, self-supporting performance and tensile property with the excellence of can realizing and the phase retardation film of rigidity.
Under the situation of the aromatic dicarboxylic phenolic compounds that uses two or more, can be by the phase retardation film that contains styrene resin and polycarbonate resin be carried out 1H-NMR measures the weight ratio of measuring aromatic dicarboxylic phenolic compounds component.
Preferred use tetrahydrofuran to be converted into polystyrene be 25 as launching solvent contains the phase retardation film of styrene resin and polycarbonate resin by GPC method being used to of measuring the weight-average molecular weight (Mw) of polycarbonate resin, 000 to 200,000, more preferably 30,000 to 150,000, preferred especially 40,000 to 100,000, most preferably 50,000 to 80,000.The polycarbonate resin of weight-average molecular weight in above-mentioned scope can provide the phase retardation film with excellent mechanical strength.
Difference between the weight-average molecular weight of optimization polycarbonate resinoid and styrene resin (Mw) (Mw of the Mw-styrene resin of polycarbonate resin) is 24,000 to 92,000, more preferably 29,000 to 87,000, preferred especially 39,000 to 77,000, most preferably 49,000 to 67,000.Difference can provide the phase retardation film of the highly transparent with excellent mechanical strength in above scope.
Phase retardation film used in the present invention can obtain in the following manner: the shrinkability film is attached to the one or both sides of the polymer film that contains polycarbonate resin and styrene resin, uses the roll-type drawing machine by vertical uniaxial tension method products therefrom to be stretched then.This shrinkability film is used for providing convergent force in the hot-stretch process on the direction vertical with draw direction, and is used to improve the refractive index of phase retardation film thickness direction.The method that the shrinkability film is attached to the one or both sides of polymer film is not particularly limited.But, its preferable methods comprises by providing between polymer film and shrinkability film and contains acrylate copolymer and make polymer film and shrinkability film bonding as the acrylic pressure-sensitive layer of base polymer, because this method show excellence on preparation rate and operability.
To prepare the example of the method for phase retardation film of the present invention with reference to figure 4 explanations.Fig. 4 is the synoptic diagram of notion that has shown the typical production of phase retardation film of the present invention.For example, the polymer film 402 that contains styrene resin and polycarbonate resin is transmitted by first transfer member 401.By lamination roller 407 and the 408 shrinkability films 404 of being furnished with pressure-sensitive adhesive layer that will transmit by second transfer member 403 and the both sides that are attached to polymer film 402 by the shrinkability film 406 of being furnished with pressure-sensitive adhesive layer that the 3rd transfer member 405 transmits.By roller 410,411,412 with 413 with different velocity ratios film longitudinally under the tension force (simultaneously under the tension force of shrinkability film thickness direction) laminate that has the shrinkability film that is attached to the polymer film both sides is carried out stretch processing, make this laminate keep constant temperature by firing equipment 409 simultaneously.Shrinkability film 404 and 406 is peeled off from the laminate that has carried out stretch processing with pressure-sensitive adhesive layer around (take-up) parts 414 and second winding unit, 416 places at the first volume, thereby obtained phase retardation film (stretched film 418).Obtaining phase retardation film 418 is wound on the 3rd winding unit 419.
The polymer film that contains styrene resin and polycarbonate resin can obtain or can obtain by melt extrusion method from solution commonly used by the casting method.The method that resin is mixed is not particularly limited.For example, be equipped with by the casting legal system under the situation of film, will be scheduled to polycarbonate resin and the styrene resin and the solvent of ratio and stir, thus the preparation homogeneous solution.Equally, under situation, with polycarbonate resin and the styrene resin fusion and the mixing of predetermined ratio by each film of melt extrusion method system.Preferably pass through the casting method by the formulations prepared from solutions polymer film, have good slickness and the inhomogeneity phase retardation film of good optical thereby provide.
As mentioned above, the shrinkability film is used for providing convergent force in the hot-stretch process in the direction vertical with draw direction, and is used to increase the refractive index of the phase retardation film thickness direction that obtains.Examples of material as the shrinkability film comprises polyester, polystyrene, tygon, polypropylene, Polyvinylchloride and polyvinylidene chloride.From the contraction homogeneity and the stable on heating angle of excellence, preferably use polypropylene screen.
Preferred shrinkability film is a stretched film, for example biaxially-stretched film or monadic stretching membrane.Stretched film can obtain by the following method: form unstretching film by extrusion molding, use synchronous biaxial stretch-formed machine etc. vertically and/or laterally unstretching film being stretched with predetermined draw ratio then.Can suitably select formation condition and stretching condition according to the composition of purpose, used resin or kind etc.From the contraction homogeneity and the thermotolerance ground angle of excellence, especially preferably use biaxial-stretched polypropylene films.
In an embodiment of the invention, under 140 ℃, the shrinkability film is shrinkage factor S longitudinally 140(MD) be 2.7 to 9.4%, and the shrinkage factor S of film Width 140(TD) be 4.6 to 15.8%.In yet another embodiment of the present invention, under 160 ℃, the shrinkability film is shrinkage factor S longitudinally 160(MD) be 13 to 23%, and the shrinkage factor S of film Width 160(TD) be 30 to 48%.Shrinkage factor can provide the phase difference value of expection and have excellent inhomogeneity phase retardation film in above-mentioned scope.
In an embodiment of the invention, under 140 ℃, the shrinkage factor S of film Width 140(TD) and film shrinkage factor S longitudinally 140(MD) the difference DELTA S between 140=S 140(MD)-S 140(TD) drop on 0.1%≤Δ S 140In≤3.9% the scope.In yet another embodiment of the present invention, under 160 ℃, the shrinkage factor S of film Width 160(TD) and film shrinkage factor S longitudinally 160(MD) the difference DELTA S between 160=S 160(MD)-S 160(TD) drop on 8%≤Δ S 160In≤30% the scope.The big shrinkage factor of MD direction may cause the evenly difficulty of stretching at the convergent force except that tensile stress on the draw direction owing to phase retardation film.Difference allows evenly to stretch in above-mentioned scope and need not the equipment of for example drawing machine is applied excessive load.
The preferred differential contraction stress T of every 2mm on 140 ℃ of following shrinkability film Widths A 140(TD) be 0.15 to 0.75N/2mm.The preferred differential contraction stress T of per unit area on 140 ℃ of following shrinkability film Widths B 140(TD) be 2.5 to 12.5N/mm 2Differential contraction stress can provide the phase difference value of expection and allow evenly to stretch in above-mentioned scope.
The preferred differential contraction stress T of every 2mm on 150 ℃ of following shrinkability film Widths A 150(TD) be 0.20 to 0.85N/2mm.The preferred differential contraction stress T of per unit area on 150 ℃ of following shrinkability film Widths B 150(TD) be 3.3 to 14.2N/mm 2Differential contraction stress can provide the phase difference value of expection and allow evenly to stretch in above-mentioned scope.
Can measure shrinkage factor S (MD) and S (TD) according to the percent thermal shrinkage A method of JIS Z1712 (except as mentioned above heating-up temperature being become 140 ℃ or 160 ℃ and sample is applied the 3g load from 120 ℃).Specifically, choosing width respectively on vertical (vertically MD) and Width (laterally TD) is that 20mm and length are five samples of 150mm.Mark in each sample center of about 100mm being separated by.Each sample that will have 3g load is hung vertically in the air circulating type constant temperature oven that keeps 140 ℃ ± 3 ℃ or 160 ℃ ± 3 ℃.With sample heating 15 minutes, from constant temperature oven, take out, (room temperature) left standstill 30 minutes under standard conditions then.Subsequently, use distance between the kind of calliper mark, thereby obtain the mean value of five measured values according to JIS B7507.Shrinkage factor can be by equation S (%)=[calculate (distance (mm) before distance (the mm)/heating between the distance (mm) before the heating between mark-heating back mark between mark) * 100.
As long as can satisfy purpose of the present invention, can select suitably and use that commercially available being used for for example generally packed, the shrinkability film of packaging for foodstuff, pallet packing, shrinkability label, hat seal and electrical isolation purposes is as above-mentioned shrinkability film.Commercially available shrinkability film can directly use, and perhaps can use after the processing of this shrinkability film being carried out for example stretch processing or shrink process.The object lesson of commercially available shrinkability film comprises " ALPHAN " (trade name, Oji paperCo.Ltd. (Oji Paper) produces), " FANCYTOP series " (Ltd. (Junshi Co., Ltd) produces for trade name, Gunze); " TORAYFAN series " (trade name, Toray Industries, Inc. (Dong Li Industrial Co., Ltd) production), " SUNTOX-OP series " (trade name, SUNTOX Co., Ltd. produces) and " TOHCELLO OP series " (trade name, TOHCELLO Co., Ltd. produces).The polymer film that contains polycarbonate resin and styrene resin is being carried out in the process of hot-stretch, temperature (being also referred to as draft temperature) in the preferred stretching furnace is the glass transition temperature of polymer film (Tg) or higher, because the phase difference value of gained phase retardation film is easy to evenly, and this film crystallization hardly (change have cloud decorative pattern).Preferred draft temperature is (Tg+1 of polymer film a ℃) to (Tg+30 ℃).
The glass transition temperature of polymer film is not particularly limited.But preferred glass attitude inversion temperature (Tg) is 110 to 185 ℃, more preferably 120 to 170 ℃, and preferred especially 125 to 150 ℃.110 ℃ or higher Tg make and are easy to prepare the film with good thermal stability.185 ℃ or the lower feasible phase difference value that is easy to by phase difference value and thickness direction in the face of stretching controlling diaphragm of Tg.Glass transition temperature (Tg) can be measured by the DSC method according to JIS K7121.
Draw ratio in the hot-stretch process of polymer film is not particularly limited, and it can suitably be set according to the residual volume of the kind of the composition of polymer film, volatile constituent etc., volatile constituent etc., phase difference value of design or the like.For example, preferred draw ratio is 1.05 to 2.00 times.The transfer rate of laminate in the drawing process (comprising polymer film and shrinkability film) is not particularly limited.But, consider the precision machining, stability of drawing machine etc., preferred transfer rate is 0.5m/min or bigger, more preferably 1m/min or bigger.
D-5. other film that is used for first optical element
In first optical element 30, can preferably have little photoelastic coefficient absolute value by lamination other film on the phase retardation film that contains polycarbonate resin and styrene resin.
The photoelastic coefficient absolute value C[590 of preferred this film] (m 2/ N) be 2.0 * 10 -13To 8.0 * 10 -11, more preferably 5.0 * 10 -13To 2.0 * 10 -11, preferred especially 2.0 * 10 -12To 6.0 * 10 -12, most preferably 2.0 * 10 -12To 5.0 * 10 -12
The material that is preferred for film forming has excellent transparency, physical strength, thermal stability, water resistance etc.Its object lesson comprises polyester resin, for example polyethylene terephthalate and Polyethylene Naphthalate; Cellulosic resin, for example diacetyl cellulose and triacetyl cellulose; Acrylic resin, for example polymethylmethacrylate; Styrene resin, for example polystyrene, vinyl cyanide/styrol copolymer, styrene resin, vinyl cyanide/styrene resin, acrylonitrile/butadiene/styrene resin, vinyl cyanide/ethylene/styrene resin, styrene/maleimide copolymer and styrene/maleic anhydride copolymers; And polycarbonate resin.Its further example comprises cycloolefin resin; Norbornene resin; Polyolefin resin, for example tygon, polypropylene and ethylene/propene copolymer; Vinyl chloride resin; Amide-type resin, for example nylon and aromatic polyamide; Acid imide resin, for example aromatic polyimide and polyimide amide; The sulfone resinoid; The polyether sulfone resin; The polyetheretherketone resinoid; The polyphenylene sulfide resinoid; The vinyl alcohol resin; Vinylidene chloride like resin; Ethene butyral resinoid; The arylide resinoid; Polyoxymethylene resinoid and epikote.Its further example comprise the polymer film of forming by the blending product of above-mentioned resin.
Preferred other film is an isotropic membrane.In instructions of the present invention, isotropic membrane refers to the little and film that can not exert an influence to optical property in actual applications of phase difference value.This isotropic membrane with little birefringence or photoelastic coefficient can be by lamination on the phase retardation film that contains polycarbonate-based film and phenylethylene film.Therefore, can reduce the polaroid differential contraction stress that is delivered on the phase retardation film or heat backlight, thereby further reduce the skew of phase difference value or inhomogeneous.This phase retardation film that contains polycarbonate resin and phenylethylene branch can cause hardly at first because the skew of the differential contraction stress of polaroid or the phase difference value that heat caused backlight or inhomogeneous.Therefore, this isotropic membrane can be united use with phase retardation film, has skew of phase difference value simultaneously of excellent display performance or inhomogeneous very little liquid crystal panel thereby provide.
The Re[590 of preferred isotropic membrane] greater than 0nm and be less than or equal to 5nm, more preferably greater than 0nm and be less than or equal to 3nm, be preferably greater than 0nm especially and be less than or equal to 2nm, most preferably greater than 0nm and be less than or equal to 1nm.
The Rth[590 of preferred isotropic membrane] for greater than 0nm and be less than or equal to 10nm, more preferably greater than 0nm and be less than or equal to 6nm, be preferably greater than 0nm especially and be less than or equal to 4nm, most preferably greater than 0nm and be less than or equal to 2nm.
The thickness of isotropic membrane can change with the quantity of the phase retardation film of isotropic membrane and/or institute's lamination.In the practical application, the thickness of this isotropic membrane can be kept suitable physical strength and can the optical property of winning the first place optical element do not impacted.For example, two phase retardation films and an isotropic membrane are being carried out in the embodiment of lamination, the thickness of preferred isotropic membrane is 20 to 120 μ m.
The object lesson of material that satisfies the isotropic membrane of phase difference value and photoelastic coefficient comprises that open loop (being total to) polymer to Norbornene derivative of passing through as required described in the JP 06-51117A carries out polymer modification (for example maleic acid addition or cyclopentadiene addition) and modified product is carried out the norbornene resin that norbornene resin that norbornene resin that hydrogenation prepares, addition polymerization by Norbornene derivative prepare and the addition copolymerization by Norbornene derivative and olefin monomer (for example ethene or alpha-olefin) prepare. Its other example comprise passing through described in the JP 2002-348324A make a kind of in many ring cycloolefin monomers (for example norborene), monocycle cycloolefin monomers and the acyclic 1-olefinic monomers in the presence of metallocene catalyst with the form of solution, suspending liquid or molten monomer or in gas phase, carry out the cycloolefin resinoid that polymerization prepares.
Its further example comprises on the side chain described in the JP 2001-253960A and has 9, polycarbonate resin of two (4-hydroxyphenyl) fluorenes of 9-and the cellulosic resin described in the JP 07-112446A.Its another example comprises the polymer film described in the JP 2001-343529A, that is, by contain have on the side chain replace and/or the thermoplastic resin (A) of the imide of non-replacement and side chain on have and replace and/or the film of the resin combination acquisition of the thermoplastic resin (B) of the phenyl of non-replacement and itrile group.Its object lesson is the polymer film by the resin combination acquisition of the alternating copolymer that contains isobutylene and N-methyl maleimide and vinyl cyanide/styrol copolymer.Its further example comprises " Development and applied technology of optical polymermaterial (development of optic polymer matter and application technology) " (the 194th to 207 page, NTS company publishes, 2003), form the monomer of the polymkeric substance that shows positive birefringence and form the random copolymers of the polymer monomer that shows negative birefringence and the polymkeric substance that mixes anisotropy low-molecular-weight molecule or birefringece crystal.But, the invention is not restricted to this.
E. second optical element
With reference to figure 1,2A and 2B, second optical element 40 be configured in liquid crystal cells 10 and polaroid 20 ' between.Second optical element 40 has optical isotropy basically.In instructions of the present invention, phrase " has optical isotropy " and refers to little phase difference value that optical element with little phase difference value can not impact the optical property of whole liquid crystal panel basically and the birefringence optics compensation that allows liquid crystal cells basically.For example, have optically isotropic optical element basically and comprise the optical element that satisfies following formula (3) and (4).
0nm≤Re[590]≤10nm …(3)
0nm≤Rth[590]≤20nm …(4)
(in expression formula (3) and (4), Re[590] and Rth[590] represent respectively 23 ℃ use down wavelength as the face of the film of the photo measure of 590nm in the phase difference value of phase difference value and thickness direction.)
For increasing the oblique contrast of liquid crystal indicator, second optical element has as far as possible little Re[590].In actual use, as described in expression formula (3), the Re[590 of second optical element] be 0 to 10nm, preferred 0 to 5nm, preferred especially 0 to 2nm, most preferably 0 arrive 1nm.
For increasing the oblique contrast of liquid crystal indicator, second optical element also preferably has as far as possible little Rth[590].In actual use, as described in expression formula (4), the Rth[590 of second optical element] be 0 to 20nm, preferred 0 to 5nm, preferred especially 0 to 3nm, most preferably 0 arrive 2nm.
With second optical element be configured to liquid crystal cells 10 and polaroid 20 ' between method be not particularly limited.Preferably by configuration bonding coat or pressure-sensitive adhesive layer (not shown) on the second optical element both sides, then a side of second optical element is attached to polaroid 20 ' a side and the opposite side of second optical element is attached to a side of liquid crystal cells 10 and make second optical element 40 be attached to liquid crystal cells 10 and polaroid 20 ' on.Can use the contrast of LCD degree of second optical element 40 to increase like this.Can suitably set the thickness of bonding coat or pressure-sensitive adhesive layer according to desired use, bond strength etc.But its thickness is generally 1 to 500 μ m, preferred 5 to 200 μ m, preferred especially 10 to 100 μ m.
The bonding agent or the contact adhesive that are used to form bonding coat or pressure-sensitive adhesive layer are not particularly limited.Its example comprises and for example contains acrylate copolymer, polysiloxane base polymer, polyester, polyurethane, polyamide, polyvinylether, vinyl acetate/vinyl chloride copolymer, improved polyalkene, epoxide polymer, fluorine-based polymer or rubber polymer (for example natural rubber base polymer or synthetic rubber base polymer) separately as base polymer those that it can suitably be selected and use.Especially, from optical clarity, cohesive (wettability, cohesiveness and the cohesive that comprise appropriateness) and the excellent against weather and the stable on heating angle of excellence, preferably use acrylic pressure-sensitive adhesive.
Second optical element 40 has optical isotropy basically, but slow axis can be detected in actual use.In this case, preferably second optical element 40 is configured so that its slow axis substantially parallel or perpendicular to the polaroid 20 of adjacency ' absorption axes.More preferably, with second optical element 40 be configured so that its slow axis be arranged essentially parallel to the polaroid 20 of adjacency ' absorption axes, thereby allow the roll-type production of film and promote adhering to of film.Therefore, production efficiency can obviously be improved.In instructions of the present invention, phrase " substantially parallel " comprise the slow axis of second optical element 40 and polaroid 20 ' absorption axes form the situation of 0 ° ± 2.0 ° angle, preferred 0 ° ± 1.0 °, more preferably 0 ° ± 0.5 °.In instructions of the present invention, phrase " perpendicular " comprise the slow axis of second optical element 40 and polaroid 20 ' absorption axes form the situation of 90 ° ± 2.0 ° angle, preferred 90 ° ± 1.0 °, more preferably 90 ° ± 0.5 °.When second optical element was used for liquid crystal indicator, angle departs from above-mentioned scope greatly may cause the reduction of Polarizer polarization degree and the reduction of contrast.
Preferred second optical element has as far as possible little thickness in the scope of self-supporting performance that film is provided and physical strength, to reduce because the skew of the differential contraction stress of polaroid or the phase difference value that heat was caused backlight or inhomogeneous.The thickness of second optical element is generally 20 to 500 μ m, more preferably 30 to 300 μ m, preferred especially 40 to 100 μ m, most preferably 50 to 80 μ m.Second optical element has the thickness in above-mentioned scope, thereby the liquid crystal panel with excellent show uniformity is provided.
Second optical element can be the laminate of single layer optical film or two or more bloomings.For blooming is carried out lamination, can contain bonding coat or pressure-sensitive adhesive layer etc. as second optical element of laminate.Blooming can be isotropic membrane or phase retardation film, as long as whole second optical element has optical isotropy basically.For example, two phase retardation films by the situation of lamination under, preferably phase retardation film is configured so that slow axis separately is perpendicular to one another, thus minimizing face in phase difference value.
As long as can satisfy the present invention, blooming is not particularly limited,, but preferred blooming has excellent transparency, physical strength, thermal stability, water shielding etc.The object lesson that forms the material of blooming comprises polyester resin, for example polyethylene terephthalate and Polyethylene Naphthalate; Cellulosic resin, for example diacetyl cellulose and triacetyl cellulose; Acrylic resin, for example polymethylmethacrylate; Styrene resin, for example polystyrene, vinyl cyanide/styrol copolymer, styrene resin, vinyl cyanide/styrene resin, acrylonitrile/butadiene/styrene resin, vinyl cyanide/ethylene/styrene resin, styrene/maleimide copolymer and styrene/maleic anhydride copolymers; And polycarbonate resin.Its further example comprises cycloolefin resin; Norbornene resin; Polyolefin resin, for example tygon, polypropylene and ethylene/propene copolymer; Vinyl chloride resin; Amide-type resin, for example nylon and aromatic polyamide; Acid imide resin, for example aromatic polyimide and polyimide amide; The sulfone resinoid; The polyether sulfone resin; The polyetheretherketone resinoid; The polyphenylene sulfide resinoid; The vinyl alcohol resin; Vinylidene chloride like resin; Ethene butyral resinoid; The arylide resinoid; Polyoxymethylene resinoid and epikote.Its further example comprise the polymer film of forming by the blending product of above-mentioned resin.
The example of blooming comprises those similar to the isotropic membrane that is used for first optical element.Wherein, from excellent transparency, excellent physical strength, excellent thermal stability, excellent water shielding performance, little photoelastic coefficient with to the angle of the excellent adhesion of polaroid, especially preferably use cellulosic resin, norbornene resin and contain isobutylene and the resin of the alternating copolymer of N-methyl maleimide and vinyl cyanide/styrol copolymer at least a polymer film.
At second optical element is by a plurality of phase retardation films being carried out under the formed situation of lamination, second optical element forms by phase retardation film is carried out lamination usually, so that to satisfy the negative electrode single shaft phase retardation film that index distribution is nx ≈ ny＞nz (being also referred to as negative electrode C plate) and satisfy index distribution be the anode single shaft phase retardation film (being also referred to as positive C plate) of nz＞nx ≈ ny thus carry out phase difference value that lamination eliminates phase difference value and thickness direction in each other the face (wherein, nx and ny represent refractive index in the interarea, nz representative thickness refractive index).In instructions of the present invention, expression formula " nx ≈ ny " is not strictly limited to the situation that shows the nx=ny relation, and the single shaft phase retardation film comprises Re[590] be 10nm or littler phase retardation film.
Anticathode C plate and positive C plate are carried out the not restriction especially of method of lamination, but preferably by between negative electrode C plate and positive C plate, providing bonding coat or pressure-sensitive adhesive layer that it is adhered to.In addition, preferably negative electrode C plate and positive C plate are configured to make that slow axis is perpendicular to one another with phase difference value in the elimination face in separately the face.Preferred second optical element uses by negative electrode C plate that satisfies following formula (7) and (8) and the positive C plate that satisfies following formula (9) and (10) are carried out the laminated film that lamination prepares.
0nm≤Re[590]≤10nm …(7)
20nm≤Rth[590]≤400nm …(8)
0nm≤Re[590]≤10nm …(9)
-400nm≤Rth[590]≤-20nm…(10)
(in expression formula (7), (8), (9) and (10), Re[590] and Rth[590] represent respectively 23 ℃ use down wavelength as the face of the film of the photo measure of 590nm in the phase difference value of phase differential and thickness direction).
The Re[590 of preferred negative electrode C plate] greater than 0nm and be less than or equal to 10nm, more preferably greater than 0nm and be less than or equal to 3nm, be preferably greater than 0nm especially and be less than or equal to 2nm, most preferably greater than 0nm and be less than or equal to 1nm.
The Rth[590 of preferred negative electrode C plate] greater than 20nm and be less than or equal to 400nm, more preferably greater than 20nm and be less than or equal to 200nm, most preferably greater than 20nm and be less than or equal to 100nm.
The thickness of preferred negative electrode C plate is 20 to 500 μ m, more preferably 30 to 300 μ m, preferred especially 40 to 100 μ m, most preferably 50 to 80 μ m.
The examples of material that is used to form negative electrode C plate comprise any suitable polymers film, by the liquid crystal material that shows the cholesteric crystal phase is cured the film for preparing, by the smectic crystal compound being cured film and the inorganic layered compounds for preparing.The object lesson that forms the polymer film of negative electrode C plate comprises cellulosic resin, for example diacetyl cellulose and triacetyl cellulose; Acryl resin, for example polymethylmethacrylate; And polycarbonate resin.Its further example comprises: the cycloolefin resinoid; Norbornene resin; Polyolefin resin is such as tygon, polypropylene and ethylene/propene copolymer; Vinyl chloride resin; Amide-type resin, for example nylon and aromatic polyamide; Acid imide resin, for example aromatic polyimide and polyimide amide; The sulfone resinoid; The polyether sulfone resin; The polyetheretherketone resinoid; The polyphenylene sulfide resinoid; The vinyl alcohol resin; Vinylidene chloride like resin; Vinyl butyral resinoid; The arylide resinoid; The polyoxymethylene resinoid; And epikote.Its further example comprise the polymer film of forming by with the admixture of above-mentioned resin.
Polymer film as negative electrode C plate can obtain through the formation of casting method by film, perhaps can obtain by stretching through any suitable drawing process.The object lesson of drawing process comprises vertical uniaxial tension method, horizontal uniaxial tension method, the synchronous biaxial stretch-formed method of vertical transverse and the biaxial stretch-formed method of vertical transverse order.Drawing process can be undertaken by using any suitable drawing machine, such as roll-type drawing machine, stenter or biaxial stretch-formed machine.Stretching can be finished by two steps or multistep.Polymer film can stretch at the Width (laterally TD) of vertical (machine direction MD) or film.
The examples of material that is used to form negative electrode C plate comprises: the polyimide film described in [0100] section of JP 2003-287750A; Passing through described in [0123] section of JP 2003-287623A is cured the film for preparing to containing the nematic crystal monomer with agent of polymerizable chirality and demonstration cholesteric crystal liquid crystal material mutually; The non-both alignment layers of discoid (discotic) liquid crystal described in [0068] section of JP 07-281028A; With described in JP 09-80233A [0034] section, by on substrate, applying the water swelling inorganic layered compounds and resulting product is carried out the film that drying prepares.The Re[590 of preferred anodes C plate] greater than 0nm and be less than or equal to 10nm, more preferably greater than 0nm and be less than or equal to 3nm, be preferably greater than 0nm especially and be less than or equal to 2nm, most preferably greater than 0nm and be less than or equal to 1nm.The Rth[590 of preferred anodes C plate] more than or equal to-400nm and less than-20nm, more preferably greater than or equal-200nm and less than-20nm, most preferably more than or equal to-100nm and less than-20nm.
The thickness of preferred anodes C plate is 0.1 to 50 μ m, more preferably 0.1 to 30 μ m, preferred especially 0.1 to 10 μ m, most preferably 0.1 to 5 μ m.The examples of material that is used to form positive C plate comprises passes through to apply the film that contains (mesogenic) side chain that has liquid crystal liquid crystal property, can form vertical orientation and be prepared by the liquid-crystal composition that shows the liquid crystal polymer that structural formula (11) is expressed down described in the embodiment 1 of JP 2002-174725A on substrate.Its another example comprise described in the embodiment 1 of JP 2003-149441 A pass through with solvent on substrate, apply contain by show liquid crystal polymer that structural formula (11) is expressed and commercially available polymerisable liquid crystal monomer combination and polymerization initiator down, form the polymerisable liquid crystal monomer even vertical orientation (being also referred to as vertical orientation), then resulting product is cured the film that makes.
Figure C20051011426600321
Fig. 5 A and 5B all are perspective diagrams that the typical preferred embodiment of employed in the present invention second optical element is described.Fig. 5 A has shown that second optical element 40 is situations of individual layer isotropic membrane.Fig. 5 B has shown that second optical element 40 is situations of the laminate of negative electrode C plate 41 and positive C plate 42.Be configured to make slow axis separately to be perpendicular to one another negative electrode C plate and positive C plate 42.Second optical element is not limited to have the structure of Fig. 5 A and 5B, and can have any suitable optically isotropic basically structure.
F. polarizing plate protective film
As the hyaline membrane of polarizing plate protective film can be configured in liquid crystal panel polaroid of the present invention do not adhere on the side of first optical element or second optical element (that is to say, the polaroid 20 and 20 of Fig. 1,2A and 2B ' the outside).
The preferably clear film has excellent transparency, physical strength, thermal stability, water shielding etc.The examples of material that is used to form hyaline membrane comprises: polyester resin, such as polyethylene terephthalate and PEN; Cellulosic resin, for example diacetyl cellulose and triacetyl cellulose; Acryl resin, for example polymethylmethacrylate; Styrene resin, for example polystyrene, vinyl cyanide/styrol copolymer, styrene resin, vinyl cyanide/styrene resin, acrylonitrile/butadiene/styrene resin, vinyl cyanide/ethylene/styrene resin, styrene/maleimide copolymer and phenylethylene/maleic anhydride copolymer; And polycarbonate resin.Its further example comprises: cycloolefin resin; Norbornene resin; Polyolefin resin, for example tygon, polypropylene and ethylene/propene copolymer; Vinyl chloride resin; Amide-type resin, for example nylon and aromatic polyamide; Acid imide resin, for example aromatic polyimide and polyimide amide; The sulfone resinoid; The polyether sulfone resin; The polyetheretherketone resinoid; The polyphenylene sulfide resinoid; The vinyl alcohol resin; Vinylidene chloride like resin; Vinyl butyral resinoid; The arylide resinoid; The polyoxymethylene resinoid; And epikote.Its further example comprise the polymer film of forming by the admixture of above-mentioned resin.Dura mater processing, anti-reflex treated, release treatment or DIFFUSION TREATMENT (being also referred to as non-glare treated) can be stood in the hyaline membrane surface that does not have polaroid to adhere on it.It is in order to prevent the infringement to the Polarizer surface that dura mater is handled, and the curable coating film with excellent hardness, smooth property etc. can use any suitable UV cured resin (such as acrylic resin or polyorganosiloxane resin) to form on the surface of transparent protective film.Anti-reflex treated is for the anti-external light reflection on the polaroid surface.Release treatment is in order to prevent the bonding of Polarizer and adjacent layer.Non-glare treated is to disturb the visual identity of the light transmission that passes through Polarizer for the external light reflection that prevents the Polarizer surface; this processing can be by for example by any suitable system (such as by the rough surface disposal system of sandblast or embossment or the system that transparent fine particles is mixed), provides uneven fine structure and finish on the surface of transparent protective film.The antiglare layer that forms by non-glare treated also can be served as and is used for the diffusion layer (for example visual angle expansion effect) that scattered light sees through Polarizer and expands visual angle etc.
G. other optical element
Next, the explanation of other optical element that is used in combination with liquid crystal panel of the present invention will be provided.Any suitable optical element that can be used in liquid crystal panel can be used as other optical element.Its example comprises the blooming through dura mater processing, anti-reflex treated, release treatment or DIFFUSION TREATMENT (being also referred to as non-glare treated).In addition, liquid crystal panel of the present invention can be used in combination with commercially available brightness enhancement film (Sumitomo (Sumitomo) 3M Co., Ltd. makes for the polarization separating film that for example has polarization-selection layer, D-BEF), thereby obtains having the display device of better display performance.
H. liquid crystal indicator
Fig. 6 is the schematic cross-section of liquid crystal indicator according to the preferred embodiment of the present invention.Notice that for clarity sake, the ratio among Fig. 6 between the length of each element, width and the thickness is different with actual components.Liquid crystal indicator 200 is furnished with: liquid crystal panel 100; Be configured in the protective seam 60 and 60 of liquid crystal panel both sides '; Be configured in the brightness enhancement film 80 in surface-treated layer 70 ' outside (backlight side); Prismatic lens 110; Optical plate 120 and backlight 130.Use through the film of dura mater processing, anti-reflex treated, release treatment, DIFFUSION TREATMENT (being also referred to as non-glare treated) etc. as surface-treated layer 70 and 70 '.Use for example has polarisation and selects the polarisation diffusion barrier of layer " D-BEFseries " (trade name is made by Sumitomo (Sumitomo) 3M Co., Ltd.) or analog as brightness enhancement film 80.Use above-mentioned optical element, thereby obtain having the display device of better display performance.As long as obtain effect of the present invention, according to the purposes of drive pattern or liquid crystal cells, the optical element that shows among Fig. 6 can replace to the small part omission or by other element.
Contrast (YW/YB) at the polar angle place of 45 ° of position angles and 60 ° is 20 or bigger, more preferably 30 or bigger, preferred especially 50 or bigger, most preferably 80 or bigger.
The application of liquid crystal panel I. of the present invention and liquid crystal indicator
The purposes of liquid crystal panel of the present invention and liquid crystal indicator is restriction especially not, but liquid crystal panel of the present invention and liquid crystal indicator can be used for various uses, such as: office automation (OA) equipment, for example personal computer display device, laptop PC and duplicating machine; Portable set, for example mobile phone, wrist-watch, digital camera, PDA(Personal Digital Assistant) and portable game machine; Household electrical appliance, for example video camera, LCD TV and micro-wave oven; In-vehicle device, for example back eye monitor, auto-navigation system monitor and automobile audio; Display device is such as the business information monitor; Safety feature, for example monitor; And nurse and medical equipment, for example nurse monitor and medical monitor.
Especially, preferred liquid crystal panel of the present invention and liquid crystal indicator are used for big LCD TV.That the preferred LCD TV screen that uses liquid crystal panel of the present invention and liquid crystal indicator is of a size of is wide 17 inches (373mm * 224mm) or bigger, more preferably wide 23 inches (499mm * 300mm) or bigger, preferred especially wide 26 inches (566mm * 339mm) or bigger, most preferably wide 32 inches (687mm * 412mm) or bigger.To use the following examples and comparing embodiment to illustrate in greater detail the present invention.The invention is not restricted to these embodiment.The following describes the analytical approach of using in an embodiment.
(1) evaluation of polycarbonate resin: use following equipment to carry out 1H-NMR under the following conditions and measure, measure polycarbonate resin from the integration ratio of resulting spectrum peak.Analyser: " JNM-EX400 ", JEOL (NEC) makes
RF device nuclear: 1H
Frequency: 400MHz
Pulse width: 45 °
Pulse-recurrence time: 10 seconds
Measure temperature: room temperature
(2) measure the molecular weight of styrene resin and the method for content: the molecular weight of styrene resin and content, calculate by gel permeation chromatography as standard items with polystyrene.Specifically, the molecular weight of styrene resin and content use with lower device and instrument, measure under following measuring condition.
Measuring samples: sample resins is dissolved in the solution for preparing 0.1wt.% in the tetrahydrofuran, and placement is spent the night.Then, filter this solution, obtain the filtrate that is used to measure with the membrane filter of 0.45 μ m.
Analyser: " HLC-8120GPC ", Tosoh Co., Ltd. makes
Post: TSKgel SuperHM-H/H4000/H3000/H2000
The size of post: 6.0mm I.D. * 150mm
Eluent: tetrahydrofuran
Flow velocity: 0.6ml/min
Detecting device: RI
Column temperature: 40 ℃
Injection volume: 20 μ l
(3) method of measurement glass transition temperature (Tg): glass transition temperature uses following equipment to measure under following measuring condition according to JISK7121.
Analyser: differential scanning calorimeter " DSC500 ", Seiko (Seiko) instrument Electronics Co., Ltd makes
The nitrogen stream of measurement gas: 20ml/min
Heating rate: 10 ℃/min
(4) method of Measurement Phase difference, wavelength dispersion, slow axis angle and transmittance: phase difference value, wavelength dispersion, slow axis angle and transmittance use the light of wavelength as 590nm down at 23 ℃, according to parallel Nicol rotary process, use automatic birefringence analyser (" KOBRA-21ADH ", trade name, Oji (prince) scientific instrument Co., Ltd. makes) measure.
(5) method of measuring light elasticity coefficient: the phase difference value of sample uses elliptical polarized light spectrometer " M-220 " (trade name, JASCO (Japanese beam split) Co., Ltd. makes) under stress, to measure, photoelastic coefficient is calculated by the slope of the function of stress and phase difference value.Specifically, use the light of wavelength down, under the stress of 5N to 15N, measure the interior phase difference value of face of the sample of 2cm * 10cm as 590nm at 23 ℃.
(6) method of measurement thickness: the digital micrometer " K-351C type " that thickness uses Anritsu (peace is upright) Co., Ltd. to make is measured.
(7) method of the shrinkage factor of measurement shrinkability film: shrinkage factor S (MD) and S (TD) measure (except heating-up temperature changes 140 ℃ or 160 ℃ into from 120 ℃ according to the percent thermal shrinkage A method of JIS Z1712; The load of 3g is added on the sample).Specifically, choosing five width by vertically (machine direction (MD)) and Width (horizontal (TD)) respectively is 20mm and length is the sample of 150mm.Each sample center at about 100mm of being separated by makes marks.Each sample that will have 3g load is hung vertically in the air circulation constant temperature oven that remains on 140 ℃ ± 3 ℃ or 160 ± 3 ℃.With sample heating 15 minutes, from constant temperature oven, take out, and kept 30 minutes down in standard conditions (room temperature).According to JIS B7507, use the distance between the kind of calliper mark then, thereby obtain the average of five measured values.Shrinkage factor can be calculated from equation S (%)=[distance (mm) before (distance (mm) between the distance (mm) before the heating between the mark-heating back mark)/heating between the mark] * 100.
(8) measure the method for shrinkability film at the differential contraction stress of Width (TD): the differential contraction stress at Width uses following equipment to measure under 140 ℃ and 150 ℃ by the TMA method.
Equipment: " TMA/SS 6100 ", Seiko (Seiko) instrument Co., Ltd. makes
Data processing: " EXSTAR6000 ", Seiko (Seiko) instrument Co., Ltd. makes
Measurement pattern: (10 ℃/min) measure of constant intensifications
Measurement gas: atmospheric air (room temperature)
Load: 20mN
Sample size: 15mm * 2mm (long side and Width (TD))
Film thickness: 60 μ m
(9) contrast of LCD degree: contrast is calculated by following liquid crystal cells and measuring equipment.Display white image and black image on liquid crystal indicator use " EZContrast 160D " (trade name, ELDIM SA makes) 45 ° at position angle and 60 ° of Y values of locating measured X YZ display system of polar angle at display screen.Oblique contrast " YW/YB " is calculated from the Y value (YW) of white image and the Y value (YB) of black image.45 ° position angle refers to from 0 ° panel grows the direction that the limit rotates 45 ° in the counterclockwise direction.
Liquid crystal cells: be installed in the liquid crystal cells in " KLV-17HR2 ", make by Sony (Sony) Co., Ltd.
Panel size: 375mm * 230mm
(10) evaluation method of the demonstration unevenness of liquid crystal indicator: use following liquid crystal cells and measuring equipment that display screen is taken a picture.In table 4, " good " refers to luminance difference on the whole front panel is 1.5680 or littler liquid crystal cells, and " bad " refers to luminance difference for greater than 1.7920 liquid crystal cells.
Liquid crystal cells: be installed in the liquid crystal cells in " KLV-17HR2 ", make by Sony (Sony) Co., Ltd.
Panel size: 375mm * 230mm
Measuring equipment: two-dimentional COLOR COMPOSITION THROUGH DISTRIBUTION measuring equipment " CA-1500 ", make by Konica Minolta (Konica Minolta) parent corporation
Measurement environment: darkroom (23 ℃).
(preparation embodiment 1)
Use phosgene as carbonate precursor, and (A) 2,2-is two-(4-hydroxyphenyl) propane and (B) 1, two (the 4-hydroxypropyls)-3,3 of 1-, it is 60 that the 5-trimethyl-cyclohexane obtains weight-average molecular weight (Mw) as aromatic dicarboxylic phenol component by conventional method, 000 and contain the polycarbonate resin of repetitive of following formula (5) and (6) representative (number-average molecular weight (Mn) is 33,000, Mw/Mn is 1.78, part by weight (A): (B) be 4: 6).With the polycarbonate resin of 70 weight portions and the weight-average molecular weight (Mw) of 30 weight portions is 1,300 (number-average molecular weight (Mn) is 716, Mw/Mn is 1.78) styrene resin (HIMER SB75, SanyoChemical Industries, Ltd. (Sanyo chemical industry Co., Ltd.) produces) join in the methylene chloride of 300 weight portions.At room temperature integral body mixes 4 hours, thereby prepares limpid solution.This solution was at room temperature left standstill 15 minutes then in the glass plate top casting.Then, this solution is peeled off from glass plate, and in baking oven 80 ℃ dry 10 minutes down, then 120 ℃ dry 20 minutes down, be that 55 μ m and glass transition temperature (Tg) are 140 ℃ polymer film thereby obtain thickness.The transmittance of resulting polymers film is 93% under the wavelength of 590nm.Phase difference value Re[590 in the face of this polymer film] be 5.0nm, the phase difference value Rth[590 of thickness direction] be 12.0nm, mean refractive index is 1.576.
Figure C20051011426600381
The biaxial-stretched polypropylene films that character is as shown in table 1 " TORAYFAN " (trade name, thickness is 60 μ m, Toray Industries, Inc. (Dong Li Industrial Co., Ltd) produces) by the both sides (thickness be 55 μ ms) of acrylic pressure-sensitive layer (thickness is 15 μ m) attached to polymer film.Subsequently, in the air circulation constant temperature oven, (apart from the temperature at 3cm place, the film back side, temperature change is ± 1 ℃) uses the roll-type drawing machine to stretch 1.27 times under 147 ℃ with products therefrom, simultaneously fixedly film vertically, thereby preparation phase retardation film A.Table 2 has shown stretching condition and the character of the phase retardation film A that obtains.
Table 1
Figure C20051011426600391
Figure C20051011426600401
Employed acrylic pressure-sensitive adhesive prepares by the following method among the preparation embodiment 1: (weight-average molecular weight is 550 as base polymer to use the acrylic acid ester in the different ninth of the ten Heavenly Stems that synthesizes by solution polymerization process, 000), with base polymer as 100 weight portions, with 3 parts by weight of cross-linking agent polyisocyanate compounds " CORONATE L " (trade name, Nippon PolyurethaneIndustry Co.Ltd. (Nippon Polyurethane Industry Co., Ltd.) produces) and catalyzer " OL-1 " (trade name, Tokyo Fine Chemical Co.Ltd. (Tokyo fine chemistry industry company) produces) mixing mutually of 10 weight portions.
The phase retardation film A that is obtained among the preparation embodiment 1 is dissolved in the tetrahydrofuran, thereby the solution of preparation 0.1wt% leaves standstill them 8 hours.Subsequently, filter this solution with the membrane filter of 0.45 μ m, and filtrate is carried out gpc measurement.With total solids content during as 100 weight portions, the content of the styrene resin of measuring by gpc measurement is 27 weight portions.
By the phase retardation film A that is obtained among the preparation embodiment 1 is carried out 1The weight ratio of fragrant dihydric phenolic compounds component is measured in the H-NMR measurement.Specifically, polymer film is dissolved in the chloroform, chloroformic solution is added drop-wise in the methyl alcohol of 100 times of weight then, go out white solid thereby precipitate (precipitation again) down at 23 ℃.This solution is filtered and is separated into the insoluble part with methyl alcohol of methyl alcohol soluble fraction.Be partly dissolved among chloroform-D to carry out methyl alcohol is insoluble 1H-NMR measures.As a result, by 11.68ppm in the H-NMR spectrum (6H) locates from 2, the peak and the 2.69ppm (6H) of the methyl of two (4-hydroxyphenyl) propane of 2-locate comfortable 1, two (the 4-hydroxyphenyl)-3 of 1-, 3,3 integrations of going up the peak of the methyl that replaces on the cyclohexyl ring of 5-trimethyl-cyclohexane are 4: 6 than the weight ratio of having determined these components.
(preparation embodiment 2)
Prepare phase retardation film B according to same procedure, except draw ratio becomes 1.30 times from 1.27 times with preparation embodiment 1.Table 2 has shown stretching condition and the character of the phase retardation film B that is obtained.
(preparation embodiment 3)
Prepare phase retardation film C according to same procedure, become 1.25 times from 1.27 times except draft temperature changes to 146 ℃ and draw ratio from 147 ℃ with preparation embodiment 1.Table 2 has shown stretching condition and the character of the phase retardation film C that is obtained.
(preparation embodiment 4)
Prepare phase retardation film D according to same procedure, become 1.20 times from 1.27 times except draft temperature changes to 145 ℃ and draw ratio from 147 ℃ with preparation embodiment 1.Table 2 has shown stretching condition and the character of the phase retardation film D that is obtained.
(preparation embodiment 5)
Prepare phase retardation film E according to same procedure, become 1.10 times from 1.27 times except draft temperature changes to 140 ℃ and draw ratio from 147 ℃ with preparation embodiment 1.Table 2 has shown stretching condition and the character of the phase retardation film E that is obtained.
(preparation embodiment 6)
Use phosgene as carbonate precursor and bisphenol-A obtains polycarbonate resin as aromatic dicarboxylic phenol component by conventional method.Then, by the acrylic pressure-sensitive layer biaxial-stretched polypropylene films is attached to the both sides of the polymer film of forming by polycarbonate resin (thickness is 60 μ m).Subsequently, in the air circulation constant temperature oven, (apart from the temperature at 3cm place, the film back side, temperature change is ± 1 ℃) uses the roll-type drawing machine that this film is stretched 1.10 times under 147 ℃, simultaneously fixedly film vertically, thereby obtain phase retardation film F.Table 2 has shown the character of the phase retardation film F that is obtained.It is employed among employed biaxial-stretched polypropylene films and acrylic pressure-sensitive adhesive and the preparation embodiment 1 among the preparation embodiment 6 that those are identical.Notice that the glass transition temperature (Tg) of the polymer film of being made up of polycarbonate resin is 150 ℃, phase difference value is 7nm stretching the front in, and the phase difference value of the preceding thickness direction of stretching is 15nm.
(preparation embodiment 7)
(content of N-methyl maleimide is 50mol% to use extruder to make the alternating copolymer of being made up of isobutylene and N-methyl maleimide of 65 weight portions, glass transition temperature is 157 ℃), the vinyl cyanide/styrol copolymer (acrylonitrile content is 27mol%) of 35 weight portions and the 2-(4 of 1 weight portion, 6-diphenyl-1,3,5-triazine-2 base)-the own oxygen base-phenol of 5-(ultraviolet light absorber) is configured as bead.Subsequently, bead was descended dry 5 hours at 100 ℃, use the single screw extrusion machine of 40nm Φ and width to extrude down at 270 ℃ then as the 400nmT-mould.The sheet molten resin is cooled off in drum cooler, thereby the preparation width is the polymer film G of about 40 μ m for about 600mm width thickness.Table 3 has shown the character of polymer film G.
Figure C20051011426600431
(preparation embodiment 8)
Use commercially available norbornene resin film " ZEONOR ZF14-040 " (trade name, thickness are 40 μ m, Zeon Corporation (once flourish Co., Ltd.)) as polymer film H.Table 3 has shown the character of polymkeric substance H.
(preparation embodiment 9)
The norbornene resin " ARTON " (JSR Corp.'s production) of 20 weight portions is joined in the cyclopentanone of 80 weight portions, thus preparation solution.With this solution in tri acetyl cellulose membrane " UZ-TAC " (trade name, Re[590] be 2.2nm, Rth[590] be 39.8nm, Fuji Photo Film Co.Ltd. (Fuji Photo Film Co., Ltd.) produces) on to be coated to thickness be 150 μ m, then with products therefrom 140 ℃ dry 3 minutes down.After the drying, the norborene class film that forms on this TAC film surface is stripped down, thereby obtains transparent cellulosic resin film, with it as polymer film I.Table 3 has shown the character of polymer film I.
(preparation embodiment 10)
Use intaglio plate formula spreader with ethyl silicate solution (the 2wt% mixed solution of ethyl acetate and isopropyl alcohol, COLCOAT Co., Ltd. produces) (thickness is 75 μ m to be coated to polyethylene terephthalate film " S-27E ", Toray Industries, Inc. (Dong Li Industrial Co., Ltd) produces) on.Products therefrom was descended dry 30 seconds at 130 ℃, was the glass, polymer film of 0.1 μ m thereby form thickness.
5 weight portions had liquid crystal liquid crystal property (mesogenic) side chain, (weight-average molecular weight (Mw) is 5 to the liquid crystal polymer that can form vertical orientation and be represented by following molecular formula (11), 000), polymerisable liquid crystal monomer " Paliocolor the LC242 " (trade name that 20 weight portions are commercially available, produce from BASFAktiengesellschaft (Bath is group not)) and 1.25 weight portion Photoepolymerizationinitiater initiaters " IRGACURE 907 " (trade name, Ciba Specialty Chemicals (the vapour Bart plants chemical company) produces) be dissolved in the cyclohexanone of 75 weight portions, thus the preparation mixed solution.Use is coated with charge bar this mixed solution is coated on the glass, polymer film laminate (polyethylene terephthalate film/glass, polymer film) as substrate.With products therefrom in the air circulation constant temperature oven 80 ℃ ± 1 ℃ dry 2 minutes down, cool to room temperature then, thus form the liquid crystal layer that is fixed on the polymerisable liquid crystal monomer that has vertical orientation on the substrate.Next, use 400mJ/cm 2Ultraviolet light from a side that has applied mixed solution this liquid crystal layer is shone (use has the irradiation apparatus of metal halide lamp as light source).The polymerisable liquid crystal monomer is cured, thereby produces positive C plate on substrate.The thickness of the positive C plate that is obtained is 0.55 μ m, Re[590] be 0.1nm, Rth[590] be-55.2nm.
Positive C C plate is peeled off from substrate, and be commercially available tri acetyl cellulose membrane " the UZ-TAC " (trade names of 80 μ m at thickness with its lamination, Re[590] be 2.5nm, Rth[590] be 60.2nm, Fuji Photo Film Co.Ltd. (Fuji Photo Film Co., Ltd.) produces) on, slow axis separately is perpendicular to one another, thus preparation polymer film J.Table 3 has shown the character of polymer film J.
(preparation embodiment 11)
" " (trade name, thickness are 100 μ m, and Zeon Corporation (once flourish Co., Ltd.) produces) is as polymer film K for ZEONOR ZF14-100 to use commercially available norbornene resin film.Table 3 has shown the character of polymer film K.
(preparation embodiment 12)
Use commercially available tri acetyl cellulose membrane " UZ-TAC " (trade name, thickness are 40 μ m, Fuji Photo Film Co.Ltd. (Fuji Photo Film Co., Ltd.)) as polymer film L.Table 3 has shown the character of polymer film L.
(preparation embodiment 13)
Use commercially available tri acetyl cellulose membrane " UZ-TAC " (trade name, thickness are 80 μ m, buy from Fuji Photo Film Co.Ltd. (Fuji Photo Film Co., Ltd.)) as polymer film M.Table 3 has shown the character of polymer film M.
(embodiment 1)
Polyvinyl alcohol film is painted in containing the aqueous solution of iodine, subsequently in borated aqueous solution, between the roller of friction speed ratio with 6 times of its uniaxial tensions, thereby obtain two polaroid P1 and P2.The polaroid P1 that obtains and P2 liquid water content separately be 23%, thickness is 28 μ m, the degree of polymerization is 99.9%, the single shaft transmittance is 43.5%.Next, liquid crystal panel is taken out from the liquid crystal indicator " KLV-17HR2 " (Sony Corporation (Sony Corp) manufacturing) that comprises IPS mode liquid crystal unit.Remove and be configured in liquid crystal cells Polarizer up and down, and clean glass surface (front and rear surfaces).
Next, with phase retardation film A as first optical element from watching the side lamination on the surface of liquid crystal cells, make the slow axis of the long side of liquid crystal cells and phase retardation film A parallel to each other.Subsequently, polaroid P1 lamination on the surface of phase retardation film A, is made the slow axis of phase retardation film A and the absorption axes (0 ° ± 0.5 °) parallel to each other of polaroid P1.Subsequently, with commercially available tri acetyl cellulose membrane " UZ-TAC " (trade name, thickness are 40 μ m, Fuji Photo Film Co.Ltd. (Fuji Photo Film Co., Ltd.) produce) lamination on the surface that does not have phase retardation film A lamination polaroid P1 thereon.
Next, on the surface of liquid crystal cells, make the slow axis of the short side of liquid crystal cells and polymer film G parallel to each other as second optical element lamination on the backlight side polymer film G.Subsequently, polaroid P2 lamination on the surface of polymer film G, is made the slow axis of polymer film G and the absorption axes (0 ° ± 0.5 °) parallel to each other of polaroid P2.Subsequently, with commercially available tri acetyl cellulose membrane " UZ-TAC " (trade name, thickness is 40 μ m, Fuji Photo Film Co.Ltd. (Fuji Photo Film Co., Ltd.) produces) lamination is on the surface that does not have polymer film G lamination polaroid P2 thereon, thus preparation structure and O-mode liquid crystal panel I identical shown in Fig. 2 A.The absorption axes of polaroid P1 and P2 be perpendicular to one another (90 ° ± 1.0 °) in Zhi Bei the liquid crystal panel thus.
This liquid crystal panel is incorporated in the original liquid crystal indicator, opens 10 minutes with backlight then, thereby measure oblique contrast.Table 4 has shown the character that is obtained.
Subsequently, opened 8 hours backlight again, in the darkroom, use two-dimentional COLOR COMPOSITION THROUGH DISTRIBUTION measurement mechanism " CA-1500 " (Konica Minolta Holdings, Inc. (Konica Minolta parent corporation) makes) that the display screen of this liquid crystal indicator is taken a picture then.As shown in Figure 7, almost do not have because the demonstration that heat caused backlight is inhomogeneous.
(embodiment 2)
Prepare liquid crystal panel according to the method identical, except first optical element is become phase retardation film B from phase retardation film A with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(embodiment 3)
Prepare liquid crystal panel according to the method identical, except first optical element is become phase retardation film C from phase retardation film A with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(embodiment 4)
Prepare liquid crystal panel according to the method identical, except first optical element is become two phase retardation film E from phase retardation film A with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.Two phase retardation film E laminations make slow axis separately parallel to each other together.
(embodiment 5)
Prepare liquid crystal panel according to the method identical, except second optical element is become polymer film H from polymer film G with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(embodiment 6)
Prepare liquid crystal panel according to the method identical, except second optical element is become polymer film J from polymer film G with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(embodiment 7)
Prepare liquid crystal panel according to the method identical, except second optical element is become polymer film K from polymer film G with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(embodiment 8)
Prepare liquid crystal panel according to the method identical with embodiment 1, except second optical element is become two polymer film K from polymer film G, and two polymer film K laminations together, and slow axis separately is perpendicular to one another.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(comparing embodiment 1)
Prepare liquid crystal panel according to the method identical, except first optical element is become phase retardation film D from phase retardation film A with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(comparative example 2)
According to embodiment 1 in identical method prepare liquid crystal panel, except first optical element is become phase retardation film E from phase retardation film A.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(comparative example 3)
Prepare liquid crystal panel according to the method identical, except second optical element is become polymer film L from polymer film G with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(comparative example 4)
Prepare liquid crystal panel according to the method identical, except second optical element is become polymer film M from polymer film G with embodiment 1.Subsequently, measure the oblique contrast of the liquid-crystal apparatus that combines this liquid crystal panel.Table 4 has shown the character that is obtained.
(comparative example 5)
Prepare liquid crystal panel according to the method identical, except first optical element is become phase retardation film F from phase retardation film A with embodiment 1.This liquid crystal panel is incorporated in the original liquid crystal indicator, and opened 8 hours backlight.Subsequently, in the darkroom, use two-dimentional COLOR COMPOSITION THROUGH DISTRIBUTION measurement mechanism " CA-1500 " (Konica Minolta Holdings, Inc. (Konica Minolta company) makes) that the display screen of this liquid crystal indicator is taken a picture.As shown in Figure 8, exist to a great extent because the big demonstration that causes backlight is inhomogeneous.
(evaluation)
Shown in embodiment 1 to 4, obtained the high liquid crystal indicator of oblique contrast, this liquid crystal indicator comprises second optical element and the Re[590 that phase difference value is little] value is at 240 first optical elements in the 350nm scope.In addition, shown in embodiment 5 to 8, obtained the high liquid crystal indicator of oblique contrast, this liquid crystal indicator comprises Rth[590] value is at 0 second optical element in the 20nm scope.Comprise embodiment 1 liquid crystal panel liquid crystal indicator in addition when backlight exist hardly when opening for a long time since heat backlight cause little demonstration inhomogeneous.Similar to embodiment, each liquid crystal indicator of embodiment 2 to 8 exists demonstration inhomogeneous hardly.But comparative example 1 to 4 provides oblique contrast low liquid crystal indicator separately, has exceeded first optical element and second optical element of above-mentioned scope because this liquid crystal indicator has comprised phase difference value separately.Shown in comparative example 5, liquid crystal indicator has comprised the liquid crystal panel that uses by the phase retardation film with big photoelastic coefficient of conventional art acquisition, thereby has to a great extent because the demonstration that heat caused backlight is inhomogeneous.
As mentioned above, liquid crystal panel of the present invention has the oblique contrast of increase, thereby very useful for the display performance that improves liquid crystal indicator.Therefore, liquid crystal panel of the present invention goes for liquid crystal indicator or LCD TV.
To those skilled in the art, to make many other changes under the situation that does not deviate from scope and spirit of the present invention be apparent and implement easily.Therefore, be to be understood that the scope of claims does not mean that the particular content that is illustrated book limits, explain widely and would rather say so.

Claims (20)

1. liquid crystal panel comprises:
Liquid crystal cells;
Be configured in the polaroid of described liquid crystal cells both sides;
Be configured in first optical element between a polaroid and the described liquid crystal cells; And
Be configured in second optical element between another polaroid and the described liquid crystal cells, wherein:
Described first optical element comprises and contains styrene resin and polycarbonate resin and satisfy the phase retardation film of following formula (1) and (2); And
Described second optical element has optical isotropy basically,
240nm≤Re[590]≤350nm …(1)
0.20≤Rth[590]/Re[590]≤0.80…(2)
In described expression formula (1) and (2), Re[590] and Rth[590] represent respectively under 23 ℃, the use wavelength is the interior phase difference value of face of the measured described film of the light of 590 nm and the phase difference value of thickness direction.
2. liquid crystal panel according to claim 1, the absorption axes of the slow axis of wherein said first optical element and a polaroid substantially parallel and with the absorption axes perpendicular of another polaroid.
3. liquid crystal panel according to claim 1, wherein said liquid crystal cells comprise the liquid crystal layer that contains the nematic crystal of even orientation under the situation that does not have electric field.
4. liquid crystal panel according to claim 3, the index distribution of wherein said liquid crystal layer are nx＞ny=nz, and wherein nx, ny and nz represent the refractive index of film at slow-axis direction, quick shaft direction and thickness direction respectively.
5. liquid crystal panel according to claim 4, wherein said liquid crystal cells comprise a kind of in IPS pattern and the FFS pattern.
6. liquid crystal panel according to claim 1, the initial alignment direction of wherein said liquid crystal cells are arranged essentially parallel to the polaroid absorption axes direction of described second optical element, one side of configuration.
7. liquid crystal panel according to claim 6, the initial alignment direction of wherein said liquid crystal cells is arranged essentially parallel to the absorption axes direction of the polaroid that is configured in described liquid crystal cells backlight side.
8. liquid crystal panel according to claim 6, the initial alignment direction of wherein said liquid crystal cells is substantially perpendicular to the absorption axes direction of the polaroid that is configured in described liquid crystal cells backlight side.
9. liquid crystal panel according to claim 1, the wavelength dispersion of wherein said first optical element is 0.81 to 1.10.
10. liquid crystal panel according to claim 1, wherein said first optical element comprises the individual layer phase retardation film that contains styrene resin and polycarbonate resin.
11. comprising, liquid crystal panel according to claim 1, wherein said first optical element comprise the described laminate that contains the phase retardation film of styrene resin and polycarbonate resin.
12. liquid crystal panel according to claim 1, wherein with total solids content during as 100 weight portions, the content of styrene resin is 10 to 40 weight portions in the described phase retardation film.
13. liquid crystal panel according to claim 1, the polycarbonate resin in the wherein said phase retardation film contain the repetitive by formula (5) and (6) representative.
Figure C2005101142660003C1
14. liquid crystal panel according to claim 1, it is 2.0 * 10 as the photo measure of 590nm that the absolute value of the photoelastic coefficient of wherein said phase retardation film uses wavelength down at 23 ℃ -11To 8.0 * 10 -11m 2/ N.
15. liquid crystal panel according to claim 1, wherein said second optical element satisfies following formula (3) and (4),
0nm≤Re[590]≤10nm …(3)
0nm≤Rth[590]≤20nm …(4)
In expression formula (3) and (4), Re[590] and Rth[590] represent respectively that to use wavelength down at 23 ℃ be the phase difference value of phase difference value and thickness direction in the face of film of photo measure of 590 nm.
At least aly be selected from cellulosic resin, norbornene resin and contain isobutylene and the alternating copolymer of N-methyl maleimide and the polymer film of vinyl cyanide/styrol copolymer 16. liquid crystal panel according to claim 1, wherein said second optical element comprise.
17. liquid crystal panel according to claim 1, wherein said second optical element comprise by the negative electrode C plate that satisfies following formula (7) and (8) and the positive C plate that satisfies following formula (9) and (10) are carried out the prepared laminated film of lamination,
0nm≤Re[590]≤10nm …(7)
20nm≤Rth[590]≤400nm …(8)
0nm≤Re[590]≤10nm …(9)
-400nm≤Rth[590]≤-20nm …(10)
In expression formula (7), (8), (9) and (10), Re[590] and Rth[590] represent respectively 23 ℃ use down wavelength as the face of the film of the photo measure of 590nm in the phase difference value of phase difference value and thickness direction.
18. liquid crystal panel according to claim 1, its outside at each polaroid further comprises diaphragm.
19. LCD TV that contains the described liquid crystal panel of claim 1.
20. liquid crystal indicator that contains the described liquid crystal panel of claim 1.
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