JP4871611B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device having an improved white luminance viewing angle. Further, the present invention includes a pair of polarizing films, a liquid crystal cell disposed between them, and an optical compensation sheet having two types of optically anisotropic layers disposed between the polarizing film and the liquid crystal cell, Further, the present invention relates to a liquid crystal display device having a light diffusion layer on the outermost surface on the viewing side, and more particularly to a bend alignment mode liquid crystal display device.

A liquid crystal display (LCD) has significant advantages of being thin, lightweight, and low power consumption compared to a cathode ray tube (CRT). The liquid crystal display device comprises a liquid crystal cell and two polarizing plates disposed on both sides of the liquid crystal cell. The liquid crystal cell includes a rod-shaped compound, two substrates for encapsulating the rod-shaped compound, and an electrode layer for applying a voltage to the rod-shaped compound. In order to orient the encapsulated rod-shaped compound, an alignment film is provided on the two substrates.
In order to remove the coloring of the image displayed on the liquid crystal cell, an optical compensation sheet (retardation plate or optically anisotropic layer) is often provided between the liquid crystal cell and the polarizing plate. The combination of the polarizing plate and the optical compensation sheet functions as an elliptically polarizing plate. In some cases, the optical compensation sheet has a function of expanding the viewing angle of the liquid crystal cell.
As the optical compensation sheet, a stretched synthetic polymer film (eg, polycarbonate film, polysulfone film) has been conventionally used.

  It has also been proposed to use an optical compensation sheet having an optically anisotropic layer formed from a discotic compound and a transparent support, instead of the synthetic polymer film. The optically anisotropic layer is formed by orienting a discotic compound and fixing the orientation state. Discotic compounds have various orientation forms, and by using discotic compounds, optical compensation sheets having optical properties that cannot be obtained with conventional synthetic polymer films can be produced. Regarding optical compensation sheets using discotic compounds, JP-A-8-50206, US Pat. Nos. 5,583,679, 5,646,703, and German Patent Application Publication No. 3911620 [Patent Documents 1 to 4] There is a description.

As the transparent support of the optical compensation sheet, a cellulose acetate film is generally used when optical isotropy (low retardation value) is required. On the other hand, when optical anisotropy (high retardation value) is required, a stretched synthetic polymer film (eg, polycarbonate film, polysulfone film) is used. In the technical field of optical materials such as optical compensation sheets, when a polymer film requires optical anisotropy (high retardation value), a synthetic polymer film is used and optical isotropy (low retardation) is used. When value) is required, it was a general principle to use a cellulose acetate film.
In European Patent Application No. 0911656 [Patent Document 5], a cellulose acetate film having a high retardation value that can be used for applications requiring optical anisotropy, overcoming the conventional general principle. Is disclosed.

In the specifications of US Pat. Nos. 4,583,825 and 5,410,422 (Patent Documents 6 and 7), a bend alignment in which a rod-shaped compound is aligned in a substantially opposite direction (symmetrically) at the upper and lower portions of a liquid crystal cell A liquid crystal display device using a mode liquid crystal cell is disclosed. Since the rod-shaped compounds are symmetrically aligned at the upper and lower portions of the liquid crystal cell, the bend alignment mode liquid crystal cell has a self-optical compensation function. For this reason, this liquid crystal mode is also called an OCB (Optically Compensatory Bend) liquid crystal mode. The bend alignment mode liquid crystal display device has an advantage of high response speed.
The bend alignment mode is characterized by a wide viewing angle and a high response speed compared to the conventional liquid crystal mode (TN mode, STN mode). However, further improvement is required compared to CRT.
In order to further improve the bend alignment mode liquid crystal display device, it is conceivable to use an optical compensation sheet in the same manner as in a general liquid crystal mode. JP-A-9-197397 [Patent Document 8] (US Pat. No. 5,805,253 [Patent Document 9]), WO96 / 37804 [Patent Document 10] (European Patent Application Publication No. 0783128) [Patent Document 11] and JP-A-11-316378 [Patent Document 12] (US Pat. No. 6,064,457 [Patent Document 13]) describe an optical compensation having an optically anisotropic layer formed from a discotic compound. A sheet and a bend alignment mode liquid crystal display device using the sheet are disclosed.
An optical compensation sheet having an optically anisotropic layer formed from these discotic compounds can be used in a bend alignment mode liquid crystal display device, so that a very wide viewing angle can be obtained. There was a problem that the visibility was lowered and the visibility deteriorated.
In Japanese Patent Application Laid-Open No. 2004-191865 [Patent Document 14], an effort has been made to combine a light diffusion layer to widen the viewing angle. However, this uneven brightness cannot be solved.

JP-A-8-50206 US Pat. No. 5,583,679 US Pat. No. 5,646,703 West German Patent Application No. 3911620 European Patent Application No. 0911656 US Pat. No. 4,583,825 US Pat. No. 5,410,422 JP-A-9-197397 US Pat. No. 5,805,253 International Publication No. 96/37804 Pamphlet European Patent Application No. 0783128 JP 11-316378 A US Pat. No. 6,064,457 JP 2004-191865 A

  An object of the present invention is to appropriately compensate the liquid crystal cell optically, make the luminance of the liquid crystal cell, particularly the bend alignment cell uniform in all directions, and realize display characteristics with a wide viewing angle.

〔４〕
該界面活性剤が下記フルオロ脂肪族基含有ポリマー２である、〔２〕に記載の液晶表示装置。

〔５〕
該光学異方性層１が、ディスコティック化合物からなることを特徴とする〔１〕乃至〔４〕のいずれかに記載の液晶表示装置。
〔６〕
該光学異方性層２が、セルロースアシレートフィルムからなることを特徴とする〔１〕乃至〔５〕のいずれかに記載の液晶表示装置。
〔７〕
該光拡散層が、ゴニオフォトメーターの散乱光プロファイルの出射角０°の光強度に対する３０°の散乱光強度を０．０５乃至０．３％の範囲に有することを特徴とする〔１〕乃至〔６〕のいずれかに記載の液晶表示装置。
〔８〕
該光拡散層上に屈折率が１．２０〜１．５０の低屈折率層が設けられていることを特徴とする〔１〕乃至〔７〕のいずれかに記載の液晶表示装置。
本発明は、上記〔１〕〜〔８〕に係る発明であるが、以下、それ以外の事項（例えば、以下に述べる（１）〜（５）の液晶表示装置など）についても記載している。 As a result of diligent research by the present inventor, by setting the retardation value of the two types of optically anisotropic layers of the optical compensation sheet and the haze value of the light diffusing layer within appropriate ranges, brightness can be improved in all viewing angle ranges of the liquid crystal cell. It was found that the display could be uniform and a good display could be realized.
An object of the present invention has been accomplished by the liquid crystal display device of which we describe below [1] to [8].
[1]
A pair of polarizing films, a bend alignment mode liquid crystal cell disposed between them, and an optical compensation sheet disposed between at least one polarizing film and the liquid crystal cell. A liquid crystal display device having an optically anisotropic layer 1 satisfying I) and (II) and an optically anisotropic layer 2 satisfying the following formulas (III) and (IV):
A liquid crystal display device comprising a light diffusion layer having a haze value of 45% or more and 80% or less on a surface on a viewing side.
(I) 1.0 <Re (40 °) / Re (0 °) <2.0
(II) 0.1 <Re (−40 °) / Re (0 °) <1.0
(III) 10 nm <Re (0 °) <70 nm
(IV) 70 nm <Rth <400 nm
[In the above formula, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction of the optically anisotropic layer measured with light having a wavelength of 632.8 nm. Re (0 °) is the Re retardation value measured by making light incident in the normal direction of the film, and Re (40 °) is the slow axis of the optically anisotropic layer and the tilt angle is 40. Re Retardation value measured with light incident as °, and Re (−40 °) is measured with light incident with the slow axis of the optically anisotropic layer as the tilt axis and tilt angle as −40 °. The positive and negative tilt angles are determined so that Re (40 °)> Re (−40 °). ]
[2]
The liquid crystal display device according to [1], wherein the optically anisotropic layer 1 contains a surfactant.
[3]
The liquid crystal display device according to [2], wherein the surfactant is the following fluoroaliphatic group-containing polymer 1.

[4]
The liquid crystal display device according to [2], wherein the surfactant is the following fluoroaliphatic group-containing polymer 2.

[5]
The liquid crystal display device according to any one of [1] to [4], wherein the optically anisotropic layer 1 is made of a discotic compound.
[6]
The liquid crystal display device according to any one of [1] to [5], wherein the optically anisotropic layer 2 is made of a cellulose acylate film.
[7]
The light diffusion layer has a scattered light intensity of 30 ° in a range of 0.05 to 0.3% with respect to a light intensity at an output angle of 0 ° of a scattered light profile of a goniophotometer [1] to The liquid crystal display device according to any one of [6].
[8]
The liquid crystal display device according to any one of [1] to [7], wherein a low refractive index layer having a refractive index of 1.20 to 1.50 is provided on the light diffusion layer.
The present invention is the invention according to the above [1] to [8], but hereinafter, other matters (for example, the liquid crystal display devices (1) to (5) described below) are also described. .

(1) It has a pair of polarizing films, a liquid crystal cell disposed between them, and an optical compensation sheet disposed between at least one polarizing film and the liquid crystal cell. ), An optically anisotropic layer 1 satisfying (II), and an optically anisotropic layer 2 satisfying the following formulas (III) and (IV):
A liquid crystal display device comprising a light diffusion layer having a haze value of 45% or more and 80% or less on a surface on a viewing side.
(I) 0.1 <Re (40 °) / Re (0 °) <3.0
(II) 0.1 <Re (−40 °) / Re (0 °) <1.0
(III) 10 nm <Re (0 °) <70 nm
(IV) 70 nm <Rth <400 nm
[In the above formula, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction of the optically anisotropic layer measured with light having a wavelength of 632.8 nm. Re (0 °) is the Re retardation value of the optically anisotropic layer measured by making light incident in the normal direction of the film, and Re (40 °) is the slow axis of the optically anisotropic layer. Re retardation value measured when light is incident with an axis and tilt angle of 40 °, and Re (−40 °) is the slow axis of the optically anisotropic layer, and the tilt angle is −40 °. The Re retardation value of the optically anisotropic layer measured by incidence of light, and the positive / negative tilt angle is determined so that Re (40 °)> Re (−40 °). ]

(2) The liquid crystal display device according to (1), wherein the optically anisotropic layer 1 is made of a discotic compound.
(3) The liquid crystal display device according to (1) or (2), wherein the optically anisotropic layer 2 is made of a cellulose acylate film.
(4) The light diffusion layer is characterized by having a scattered light intensity of 30 ° with respect to the light intensity at an output angle of 0 ° of the scattered light profile of the goniophotometer in a range of 0.05 to 0.3% ( The liquid crystal display device according to any one of 1) to (3).
(5) The liquid crystal display device according to any one of (1) to (4), wherein a low refractive index layer having a refractive index of 1.20 to 1.50 is provided on the light diffusion layer. .
(6) The liquid crystal display device according to any one of (1) to (5), wherein the liquid crystal cell is in a bend mode.

  In the liquid crystal display device of the present invention, the retardation value of the two types of optically anisotropic layers of the optical compensation sheet is set to an appropriate range, and the light diffusion layer having an appropriate haze value is provided on the outermost surface on the viewing side. The liquid crystal cell can be optically compensated appropriately, and an image with a wide white luminance viewing angle in the rubbing direction of the liquid crystal cell can be displayed. The present invention is particularly effective in a liquid crystal display device using a bend alignment mode liquid crystal cell.

  Hereinafter, the present invention will be described in detail.

[Re (λ), Rth (λ)]
In this specification, Re (λ) and Rth (λ) represent in-plane retardation and retardation in the thickness direction at a wavelength λ, respectively. Re (λ) is measured in KOBRA 21ADH (manufactured by Oji Scientific Instruments) by making light having a wavelength of λ nm incident in the normal direction of the film. Rth (λ) is 10 ° from −50 ° to + 50 ° with respect to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH) and the tilt axis (rotating axis). In each step, light of wavelength λ nm is incident from each inclined direction and measured at 11 points, and KOBRA 21ADH calculates based on the measured retardation value, the assumed average refractive index, and the input film thickness value. . Here, as the assumed value of the average refractive index, values in the polymer handbook (John Wiley & Sons, Inc.) and catalogs of various optical films can be used. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of the main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). The KOBRA 21ADH calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

[Basic configuration of liquid crystal display]
FIG. 1 is a conceptual diagram showing the relationship of optical compensation in a liquid crystal display device using a bend alignment mode liquid crystal cell according to a preferred embodiment of the present invention. As shown in FIG. 1, a bend-aligned liquid crystal cell (10) is composed of an optically anisotropic layer 1 (31A, 31B) formed from a liquid crystalline compound such as a discotic compound and a polymer film having a high retardation, for example. Optical anisotropy 2 (32A, 32B) cooperates to compensate optically.
The rubbing direction (RD1, RD4) for aligning the discotic compound which is a preferred embodiment of the optically anisotropic layer 1 (31A, 31B) is antiparallel to the rubbing direction (RD2, RD3) of the liquid crystal cell. When set, the liquid crystal molecules of the bend alignment liquid crystal cell (10) and the discotic compound which is the optically anisotropic layer 1 (31A, 31B) correspond to each other and optically compensate. And it is designed so that the optical anisotropy of the optically anisotropic layer 2 (32A, 32B) corresponds to the liquid crystal molecules aligned substantially vertically in the center of the bend alignment liquid crystal cell (10). Yes. The ellipses entered in the optical anisotropic layer 2 (32A, 32B) are refractive index ellipses generated by the optical anisotropy of the optical anisotropic layer 2. Thus, the optical anisotropy of the liquid crystal cell is adjusted by adjusting the optical characteristics of the optical anisotropic layer 1 and the optical anisotropic layer 2 in accordance with the orientation of the liquid crystal in the black display state of the liquid crystal cell. High compensation is possible and a wide viewing angle can be realized.

In order to make the luminance uniform according to the viewing angle of the present invention, it is preferable that the optically anisotropic layer 1 does not have a direction in which the Re (θ) value is 0, and the following formulas (I) and (II) are It is preferable to have satisfactory values of Re (0 °), Re (40 °) and Re (−40 °).
(I) 0.1 <Re (40 °) / Re (0 °) <3.0
More preferably, 0.5 <Re (40 °) / Re (0 °) <2.5
Most preferably, 1.0 <Re (40 °) / Re (0 °) <2.0.
(II) 0.1 <Re (−40 °) / Re (0 °) <1.0
In formulas (I) and (II), Re (0 °) is the Re retardation value in the plane of the optically anisotropic layer measured with light having a wavelength of 632.8 nm, and Re (40 °) is optically anisotropic. This is a Re retardation value measured by incident light having a wavelength of 632.8 nm with the slow axis of the optical layer as the tilt axis and the tilt angle of 40 °, and Re (−40 °) is the retardation of the optically anisotropic layer. It is a Re retardation value measured by making light having a wavelength of 632.8 nm incident with the phase axis being the tilt axis and the tilt angle being −40 °. The tilt angle is determined so that Re (40 °)> Re (−40 °).
More preferably, the Re values measured at other wavelengths of 450 nm and 550 nm satisfy (I) and (II), and the Re values satisfy (I) and (II) at all wavelengths of 380 nm to 780 nm. Most preferred.
In this specification, a range of a polar angle (angle of inclination from the normal line) that is 50% with respect to the front white luminance is defined as a white luminance viewing angle.

  The rubbing direction (RD2, RD3) of the liquid crystal cell may be an arbitrary direction in the screen, but is preferably a horizontal direction, a vertical direction, a 45 ° direction, and a 135 ° in the screen. From the viewpoint of top / bottom / left / right and in-plane uniformity, 45 ° or 135 ° is more preferable.

When two polarizing films are arranged in a crossed Nicol arrangement, the transmittance seen from the normal direction of the polarizing film is very low, but the viewing angle is tilted between the transmission axes of two orthogonal polarizing films from the normal direction. And the transmittance increases. This is because SID98 DIGEST p. This is because, as described in 315, by tilting the viewing angle, the angle formed by the transmission axes of the incident-side polarizing film and the outgoing-side polarizing film deviates from the crossed Nicols arrangement (90 °). Light leakage when the viewing angle is tilted is to use a combination of a positive a-plate and a positive c-plate, a combination of a negative a-plate and a negative c-plate, or a biaxial film. Can be greatly reduced. Here, in the case of a combination of a-plate and c-plate, the optical axis of the a-plate is parallel to the transmission axis of the polarizing film, and in the case of a biaxial film, the slow axis is the transmission axis of the polarizing film. Placed parallel to
By adjusting the Re retardation value and Rth retardation value of the optically anisotropic layer 2 of the present invention, not only the function of compensating the optical anisotropy of the liquid crystal cell but also the function of the above wide viewing angle polarizing plate is realized. can do.

It is preferable for the color at the time of black display that the wavelength dispersion of the optically anisotropic layer 1 and the wavelength dispersion of the liquid crystal used in the cell match. However, even when the optically anisotropic layer 1 and the liquid crystal cell have different wavelength dispersions, it is possible to make the color of black display neutral by the following means (1) or (2).
(1) Adjust the voltage of each R, G, B pixel to minimize the transmittance of each R, G, B pixel.
(2) The cell gap of each R, G, B pixel is adjusted to minimize the transmittance of each R, G, B pixel.

In the liquid crystal display device of the present invention, it is desirable that the optically anisotropic layers 1 and 2 have a certain wavelength dispersion value. Α1 which is the wavelength dispersion value defined by the following formula (V) of the optically anisotropic layer 1 is preferably 1.0 to 2.0, and more preferably 1.1 to 1.9. 1.2 to 1.8 is most preferable.
(V) αn = Re (400 nm) / Re (550 nm)
In the formula (V), Re (400 nm) is a Re retardation value measured with light having a wavelength of 400 nm, and Re (550 nm) is a Re retardation value measured with light having a wavelength of 550 nm.
Α2 which is the wavelength dispersion value defined by the upper basic formula (V) of the optically anisotropic layer 2 preferably satisfies the following formula (VI), and further satisfies the following formula (VI-2). It is preferable that the following formula (VI-3) is satisfied.
(VI) (1.4-0.5α1) <α2 <(2.3-0.5α1)
(VI-2) (1.5-0.5α1) <α2 <(2.2-0.5α1)
(VI-3) (1.6-0.5α1) <α2 <(2.1-0.5α1)

FIG. 2 is a chart showing preferred regions of the wavelength dispersion value (α1) of the optically anisotropic layer 1 and the wavelength dispersion value (α2) of the optically anisotropic layer 2.
The straight line in the chart corresponds to the linear function shown below.
a1: α1 = 1.0, a2: α1 = 1.1, a3: α1 = 1.2
b1: α1 = 2.0, b2: α1 = 1.9, b3: α1 = 1.8
c1: α2 = 1.4−0.5α1
c2: α2 = 1.5−0.5α1
c3: α2 = 1.6−0.5α1
d1: α2 = 2.3-0.5α1
d2: α2 = 2.2−0.5α1
d3: α2 = 2.1−0.5α1
A region surrounded by the straight lines a1, b1, c1, and d1 is a preferable chromatic dispersion value in the present invention. A region surrounded by a2 instead of a1 is more preferable, and a region surrounded by a3 instead of a2 is more preferable. The relationship between b1 to b3, c1 to c3, and d1 to d3 is the same as that for a1 to a3.

  The details of the present invention will be described below.

[Optically anisotropic layer 1]
The optically anisotropic layer 1 is preferably formed from a liquid crystalline compound. The optically anisotropic layer 1 can be directly formed on the surface of the transparent support. An alignment film may be formed on the transparent support, and the optically anisotropic layer 1 may be formed on the alignment film. Alternatively, the optically anisotropic layer 1 can be formed from a liquid crystalline compound on another substrate, and then the optically anisotropic layer 1 can be transferred to a transparent support. An adhesive layer may be provided on the transparent support to which the optically anisotropic layer 1 is transferred. In this case, the transparent support preferably functions as the optically anisotropic layer 2 of the present invention.
The liquid crystal compound is preferably a rod-like liquid crystal compound or a discotic (discotic) liquid crystal compound. The rod-like liquid crystal compound and the discotic liquid crystal compound may be a polymer liquid crystal. In the formation of the optically anisotropic layer 1, the liquid crystalline compound may not exhibit liquid crystallinity due to polymerization or crosslinking.

  The rod-like liquid crystalline compounds include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano substituted phenyl pyrimidines, alkoxy substituted phenyl pyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles. Further, the rod-like liquid crystal compound includes a metal complex. In addition, a liquid crystal polymer containing a molecular structure corresponding to a rod-like liquid crystal compound in a repeating unit can also be used. In other words, the rod-like liquid crystalline compound may be bonded to a polymer to form a liquid crystal polymer. For rod-like liquid crystalline compounds, see Chapter 4, Chapter 7 and Chapter 11 of the Chemistry of the Quarterly Chemical Review Vol. 22 Liquid Crystal Chemistry (1994) edited by the Chemical Society of Japan, and the 142nd Committee of the Japan Society for the Promotion of Science. Described in Chapter 3.

The birefringence of the rod-like liquid crystal compound is preferably 0.001 to 0.7.
The rod-like liquid crystalline compound preferably has a polymerizable group in order to fix its alignment state. The polymerizable group is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.

  Discotic liquid crystalline compounds are C.I. Destrade et al., Mol. Cryst. 71, 111 (1981), benzene derivatives described in C.I. Destrade et al., Mol. Cryst. 122, 141 (1985), Physics lett, A, 78, 82 (1990); Kohne et al., Angew. Chem. 96, page 70 (1984) and the cyclohexane derivatives described in J. Am. M.M. Lehn et al. Chem. Commun. , 1794 (1985), J. Am. Zhang et al., J. Am. Chem. Soc. 116, 2655 (1994), including azacrown and phenylacetylene macrocycles.

The discotic liquid crystalline compound generally has a structure in which side chains (eg, linear alkyl groups, alkoxy groups, substituted benzoyloxy groups) are substituted radially with respect to the mother nucleus at the center of the molecule. The discotic liquid crystalline compound is preferably a compound in which a molecule or an assembly of molecules has rotational symmetry and can impart a certain orientation.
When the optically anisotropic layer 1 is formed from a discotic liquid crystalline compound, the compound finally contained in the optically anisotropic layer 1 no longer needs to exhibit liquid crystallinity. For example, a low molecular weight discotic liquid crystalline compound has a group that reacts with heat or light, and undergoes a polymerization reaction or a crosslinking reaction with heat or light to increase the molecular weight, thereby forming the optically anisotropic layer 1. be able to. If the discotic liquid crystalline compound has a high molecular weight, the liquid crystallinity is usually lost. A preferred discotic liquid crystalline compound is described in JP-A-8-50206. The polymerization of the discotic liquid crystalline compound is described in JP-A-8-27284.

In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Accordingly, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following formula.
D (-LQ) _n
In the formula, D is a discotic core, L is a divalent linking group, Q is a polymerizable group, and n is an integer of 4 to 12.

  An example of the disk-shaped core (D) is shown below. In each of the following examples, LQ (or QL) means a combination of a divalent linking group (L) and a polymerizable group (Q).

  In the above formula, the divalent linking group (L) is a divalent group selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. The linking group is preferably. The divalent linking group (L) is a divalent combination of at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO-, -NH-, -O-, and -S-. More preferably, it is a linking group. The divalent linking group (L) is most preferably a divalent linking group in which at least two divalent groups selected from the group consisting of an alkylene group, an arylene group, -CO- and -O- are combined. . The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The arylene group preferably has 6 to 10 carbon atoms.

Examples of the divalent linking group (L) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (Q). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group. The alkylene group, alkenylene group and arylene group may have a substituent (eg, an alkyl group).
L1: -AL-CO-O-AL-
L2: -AL-CO-O-AL-O-
L3: -AL-CO-O-AL-O-AL-
L4: -AL-CO-O-AL-O-CO-
L5: -CO-AR-O-AL-
L6: -CO-AR-O-AL-O-
L7: -CO-AR-O-AL-O-CO-
L8: -CO-NH-AL-
L9: -NH-AL-O-
L10: -NH-AL-O-CO-

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

The polymerizable group (Q) of the above formula is determined according to the type of polymerization reaction. The polymerizable group (Q) is preferably an unsaturated polymerizable group or an epoxy group, more preferably an unsaturated polymerizable group, and most preferably an ethylenically unsaturated polymerizable group.
In the above formula, n is an integer of 4 to 12. A specific number is determined according to the type of the disk-shaped core (D). In addition, although the combination of several L and Q may differ, it is preferable that it is the same.

As for the orientation of the liquid crystalline compound, the average direction of the molecular symmetry axis of the optically anisotropic layer 1 is preferably 43 ° to 47 ° with respect to the longitudinal direction.
In the hybrid alignment, the angle between the molecular symmetry axis of the liquid crystal compound and the surface of the support increases or decreases in the depth direction of the optically anisotropic layer 1 and with an increase in the distance from the surface of the support. The angle preferably decreases with increasing distance. Further, the change in angle can be a continuous increase, a continuous decrease, an intermittent increase, an intermittent decrease, a change including a continuous increase and a continuous decrease, or an intermittent change including an increase and a decrease. The intermittent change includes a region where the inclination angle does not change in the middle of the thickness direction.
If the angle increases or decreases as a whole, the angle may include a region where the angle does not change. The angle preferably varies continuously.

In general, the average direction of the molecular symmetry axis of the liquid crystal compound can be adjusted by selecting a material of the liquid crystal compound or the alignment film or by selecting a rubbing treatment method. In the case of an optical compensation film in which the slow axis of the transparent support and the slow axis of the optically anisotropic layer 1 are neither perpendicular nor parallel to each other, the rubbing treatment is performed in a direction different from the slow axis of the transparent support. The slow axis direction of the anisotropic layer 1 can be adjusted.
In general, the molecular symmetry axis direction of the liquid crystalline compound on the surface side (air side) of the optically anisotropic layer 1 can be adjusted by selecting the type of the liquid crystalline compound or the additive used in combination with the liquid crystalline compound. . Examples of the additive used in combination with the liquid crystal compound include a plasticizer, a surfactant, a polymerizable monomer, and a polymer. Similarly, the degree of change in the orientation direction of the molecular symmetry axis can be adjusted by selecting the liquid crystal compound and the additive. Regarding the surfactant, it is desirable to adjust the relationship with the surface tension control function of the coating solution.

  The plasticizer, surfactant and polymerizable monomer used together with the liquid crystal compound are compatible with the discotic liquid crystal compound and may change the tilt angle of the liquid crystal compound or do not inhibit the alignment. preferable. A polymerizable monomer (eg, a compound having a vinyl group, a vinyloxy group, an acryloyl group and a methacryloyl group) is preferred. The addition amount of the compound is preferably in the range of 1 to 50% by mass, more preferably in the range of 5 to 30% by mass with respect to the liquid crystalline compound. In addition, when a monomer having 4 or more polymerizable functional groups is mixed and used, the adhesion between the alignment film and the optically anisotropic layer 1 can be improved.

When a discotic liquid crystalline compound is used as the liquid crystalline compound, a polymer that has a certain degree of compatibility with the discotic liquid crystalline compound and can change the tilt angle of the discotic liquid crystalline compound is added to the optically anisotropic layer 1. It is preferable to add.
The polymer is preferably cellulose ester or cellulose ether, and more preferably cellulose ester. Examples of cellulose esters include cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate. Examples of cellulose ethers include hydroxypropyl cellulose. The amount of the polymer added is adjusted so as not to inhibit the alignment of the discotic liquid crystalline compound. The amount of the polymer added is preferably in the range of 0.1 to 10% by mass, more preferably in the range of 0.1 to 8% by mass, and most preferably in the range of 0.1 to 5% by mass with respect to the discotic liquid crystalline compound. preferable.

The discotic nematic liquid crystal phase-solid phase transition temperature in the discotic liquid crystalline compound is preferably 70 to 300 ° C, more preferably 70 to 170 ° C.
The thickness of the optically anisotropic layer 1 is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and still more preferably 1 to 10 μm.

[Alignment film]
An alignment film is preferably provided between the transparent support and the optically anisotropic layer 1.
The alignment film is preferably a layer made of a crosslinked polymer. Crosslinkable polymers can be used. For example, a polymer having a crosslinkable functional group can be crosslinked by reacting between the polymers by light, heat, or PH change. Moreover, you may bridge | crosslink a polymer using a crosslinking agent. By using a crosslinking agent that is a compound having high reaction activity, a bonding group derived from the crosslinking agent is introduced between the polymers to crosslink between the polymers.

The alignment film made of a crosslinked polymer is usually subjected to a treatment such as light, heat or pH adjustment after a coating liquid containing a crosslinkable polymer or a mixture of a polymer and a crosslinking agent is applied on a transparent support. It can be formed by performing.
In the rubbing step, it is preferable to increase the degree of crosslinking in order to suppress dust generation in the alignment film. A value (1- (Ma / Mb) obtained by subtracting 1 from the ratio (Ma / Mb) of the amount (Ma) of the crosslinking agent remaining after crosslinking to the amount (Mb) of the crosslinking agent added to the coating solution. )) Is defined as the degree of crosslinking, the degree of crosslinking is preferably 50% to 100%, more preferably 65% to 100%, and most preferably 75% to 100%.

Examples of the polymer used for the alignment film are polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, polystyrene, polymaleimide, polyvinyl alcohol, modified polyvinyl alcohol, poly (N-methylolacrylamide), polyvinyltoluene, chlorosulfonated polyethylene. , Nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, polyvinyl acetate, polyethylene, carboxymethylcellulose, gelatin, polypropylene, polycarbonate and copolymers thereof (eg acrylic acid / methacrylic acid copolymer, styrene / maleimide) Copolymer, styrene / vinyl toluene copolymer, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer). Silane coupling agents can also be used as the polymer. The polymer is preferably water soluble.
Poly (N-methylolacrylamide), carboxymethylcellulose, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are preferred, gelatin, polyvinyl alcohol and modified polyvinyl alcohol are more preferred, and polyvinyl alcohol and modified polyvinyl alcohol are most preferred.

The saponification degree of polyvinyl alcohol and modified polyvinyl alcohol is preferably 70 to 100%, more preferably 80 to 100%, and still more preferably 85 to 95%. The polymerization degree of polyvinyl alcohol and modified polyvinyl alcohol is preferably 100 to 3000.
The introduction of the modifying group in the modified polyvinyl alcohol may be any of copolymerization modification, chain transfer modification, and block polymerization modification. Examples of the modifying group introduced by copolymerization include -COONa, -Si (OX) ₃ (X is a hydrogen atom or an alkyl group), -N (CH ₃ ) ₃ · Cl, -C ₉ H ₁₉ , -COO, containing _{-SO 3 Na, -C 12 H 25} . Examples of the modifying group to be introduced in the chain transfer include -COONa, -SH, a -C ₁₂ H _25. Examples of the modifying group to be introduced in block _{polymerization, -COOH, -CONH 2, -COOR (} R is an alkyl group), - comprising a C ₆ H _5. An alkylthio group is also a preferred modifying group.
The modified polyvinyl alcohol is described in JP-A-8-338913.

When a hydrophilic polymer such as polyvinyl alcohol is used for the alignment film, it is preferable to control the water content from the viewpoint of the degree of hardening. The moisture content is preferably 0.4 to 2.5%, more preferably 0.6 to 1.6%. The water content can be measured with a commercially available Karl Fischer moisture content measuring device.
The alignment film preferably has a thickness of 10 μm or less.

[Optically anisotropic layer 2]
The optically anisotropic layer 2 is preferably composed of at least one polymer film. In this case, the optically anisotropic layer 2 may function as a transparent support for the optically anisotropic layer 1, that is, as a transparent support for the optical compensation sheet. Even if the optically anisotropic layer 2 is composed of a plurality of polymer films, the effects of the present invention can be achieved. Specifically, the optical anisotropy of the optically anisotropic layer 2 has a Re retardation value measured with light having a wavelength of 632.8 nm in a range of 10 to 70 nm and light having a wavelength of 632.8 nm. The measured Rth retardation value is in the range of 70 to 400 nm. When two optically anisotropic layers 2 are used for the liquid crystal display device, the Rth retardation value is preferably 70 to 200 nm. When only one optically anisotropic layer 2 is used in the liquid crystal display device, the Rth retardation value is preferably 70 to 400 nm.
The Re retardation value and the Rth retardation value are represented by the formula: Re (λ) = (nx−ny) × d and the formula: Rth (λ) = {(nx + ny) / 2−nz} × d, respectively. . [In the formula, Re (λ) is a front retardation value (unit: nm) at a wavelength λnm, and Rth (λ) is a retardation value (unit: nm) in a film thickness direction at a wavelength λnm. Further, nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film, and d is the thickness of the film. That's it. ]

Further, from the viewpoint of reducing the color change due to the viewing angle, the optically anisotropic layer 2 satisfies the range of α3 value defined by the following formula (1) of 0.10 to 0.95, and the following formula (2) It is preferable that the α4 value defined by the formula satisfies the range of 1.01-1.50, the β1 value defined by the following formula (3) satisfies the range of 0.40-0.95, and the following formula ( It is preferable that the β2 value defined by 4) satisfies the range of 1.05 to 1.93, and Rth (550) is 70 to 400 nm.
(1) α3 value = Re (450) / Re (550)
(2) α4 value = Re (650) / Re (550)
(Where Re (450) is the retardation value of the film for light having a wavelength of 450 nm; Re (550) is the retardation value of the film for light having a wavelength of 550 nm; Re (630) is a wavelength of 630 nm. (This is the retardation value of the film with respect to the light.)
(3) β1 value = {Re (450) / Rth (450)} / {Re (550) / Rth (550)}
(4) β2 value = {Re (650) / Rth (650)} / {Re (550) / Rth (550)}
(In the formula, Re (λ) is a retardation value of the film with respect to light having a wavelength of λ nm; Rth (λ) is a retardation value of the film with respect to light having a wavelength of λ nm.)

The optically anisotropic layer 2 preferably has an in-plane Re value, that is, a slow axis, and its angle is preferably 2 ° or less with respect to the longitudinal or width direction of the film. It is more preferably 1 ° or less, and most preferably 0.5 ° or less. The direction of the average value of the slow axis angle is defined as the average direction of the slow axis. The standard deviation of the slow axis angle is preferably 1.5 ° or less, more preferably 0.8 ° or less, and most preferably 0.4 ° or less. The angle of the slow axis in the plane of the optically anisotropic layer 2 is defined by the angle between the slow axis and the reference line, where the longitudinal or width direction of the optically anisotropic layer 2 is the reference line (0 °). To do.
The optically anisotropic layer 2 preferably has a light transmittance of 80% or more, and preferably has a photoelastic coefficient of 60 × 10 ⁻¹² m ² / N or less.

In a transmissive liquid crystal display device using an optical compensation sheet, “frame-shaped display unevenness” may occur in the periphery of the screen when the time after energization elapses. This unevenness is caused by an increase in the transmittance at the periphery of the screen, and is particularly noticeable during black display. In the transmissive liquid crystal display device, heat is generated from the backlight, and a temperature distribution is generated in the liquid crystal cell surface. The change in the optical characteristics (retardation value, slow axis angle) of the optical compensation sheet due to this temperature distribution is the cause of occurrence of “frame-like display unevenness”. The change in the optical characteristics of the optical compensation sheet is caused by elastic deformation of the optical compensation sheet because expansion or contraction of the optical compensation sheet due to temperature rise is suppressed by adhesion to the liquid crystal cell or the polarizing plate.
In order to suppress “frame-like display unevenness” that occurs in the transmissive liquid crystal display device, it is preferable to use a polymer film having high thermal conductivity for the optically anisotropic layer 2. Examples of polymers having high thermal conductivity include cellulose polymers such as cellulose acetate (thermal conductivity (hereinafter the same): 0.22 W / (m · K)), polycarbonate (0.19 W / (m · K)). ) And a cyclic olefin polymer such as a norbornene polymer (0.20 W / (m · K)).
Commercially available polymers, for example, commercially available norbornene polymers (Arton, manufactured by JSR Corporation; Zeonoa, manufactured by Nippon Zeon Co., Ltd., Zeonex; manufactured by Nippon Zeon Corporation) may be used. Polycarbonate copolymers are described in JP-A Nos. 10-176046 and 2001-253960.

From the above viewpoint, the optically anisotropic layer 2 is preferably a cellulose polymer, more preferably a cellulose ester, and further preferably a lower fatty acid ester of cellulose. Lower fatty acid means a fatty acid having 6 or less carbon atoms. The number of carbon atoms is preferably 2 (cellulose acetate), 3 (cellulose propionate) or 4 (cellulose butyrate). Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate may be used.
Cellulose acetate (cellulose diacetate, cellulose triacetate) is particularly preferred. Most preferred is cellulose triacetate having an acetylation degree of 59.0 to 61.5%. The degree of acetylation means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation follows the measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like).
The polymer has a viscosity average degree of polymerization (DP) of preferably 250 or more, and more preferably 290 or more. The polymer preferably has a narrow molecular weight distribution of Mm / Mn (Mm is a mass average molecular weight and Mn is a number average molecular weight) by gel permeation chromatography. The specific value of Mm / Mn is preferably 1.00 to 1.70, more preferably 1.30 to 1.65, and most preferably 1.40 to 1.60. .

In order to adjust the retardation of the polymer film, an aromatic compound having at least two aromatic rings can be used as a retardation increasing agent.
When a cellulose acetate film is used as the polymer film, the aromatic compound is used in the range of 0.01 to 20 parts by mass with respect to 100 parts by mass of cellulose acetate. The aromatic compound is preferably used in the range of 0.05 to 15 parts by mass, more preferably in the range of 0.1 to 10 parts by mass with respect to 100 parts by mass of cellulose acetate. Two or more aromatic compounds may be used in combination.
The aromatic ring of the aromatic compound includes an aromatic hetero ring in addition to the aromatic hydrocarbon ring. The molecular weight of the retardation increasing agent is preferably 300 to 800.
The retardation increasing agent is described in JP-A Nos. 2000-1111914, 2000-275434, 2001-166144 and International Publication No. 00/02619.

It is preferable to produce a polymer film by a solvent cast method. In the solvent cast method, a film is produced using a solution (dope) in which a polymer is dissolved in an organic solvent. The organic solvent is a solvent selected from ethers having 2 to 12 carbon atoms, ketones having 3 to 12 carbon atoms, esters having 2 to 12 carbon atoms, and halogenated hydrocarbons having 1 to 6 carbon atoms. It is preferable to contain.
The ether, ketone and ester may have a cyclic structure. A compound having two or more functional groups of ether, ketone and ester (that is, —O—, —CO— and —COO—) can also be used as the organic solvent. The organic solvent may have other functional groups such as alcoholic hydroxyl groups.

Examples of ethers include diisopropyl ether, dimethoxymethane, dimethoxyethane, 1,4-dioxane, 1,3-dioxolane, tetrahydrofuran, anisole and phenetole. Examples of ketones include acetone, methyl ethyl ketone, diethyl ketone, diisobutyl ketone, cyclohexanone and methylcyclohexanone. Examples of esters include ethyl formate, propyl formate, pentyl formate, methyl acetate, ethyl acetate and pentyl acetate. Examples of the organic solvent having two or more kinds of functional groups include 2-ethoxyethyl acetate, 2-methoxyethanol and 2-butoxyethanol. The number of carbon atoms of the halogenated hydrocarbon is preferably 1 or 2, and most preferably 1. The halogen of the halogenated hydrocarbon is preferably chlorine. The proportion of halogenated hydrocarbon hydrogen atoms substituted with halogen is preferably 25 to 75 mol%, more preferably 30 to 70 mol%, and more preferably 35 to 65 mol%. More preferably, it is 40 to 60 mol%, and most preferably. Methylene chloride is a representative halogenated hydrocarbon.
Two or more organic solvents may be mixed and used.

  A polymer solution can be prepared by a general method. The general method means that the treatment is performed at a temperature of 0 ° C. or higher (room temperature or high temperature). The solution can be prepared using a dope preparation method and apparatus in a normal solvent cast method. In the case of a general method, it is preferable to use a halogenated hydrocarbon (particularly methylene chloride) as the organic solvent. The amount of the polymer is adjusted so that it is contained in an amount of 10 to 40% by mass in the resulting solution. The amount of polymer is more preferably 10 to 30% by mass. Arbitrary additives described later may be added to the organic solvent (main solvent). The solution can be prepared by stirring the polymer and the organic solvent at room temperature (0 to 40 ° C.). High concentration solutions may be stirred under pressure and heating conditions. Specifically, the polymer and the organic solvent are put in a pressure vessel and sealed, and stirred while heating to a temperature not lower than the boiling point of the solvent at normal temperature and in a range where the solvent does not boil. The heating temperature is usually 40 ° C. or higher, preferably 60 to 200 ° C., more preferably 80 to 110 ° C.

Each component may be roughly mixed in advance and then placed in a container. Moreover, you may put into a container sequentially. The container needs to be configured so that it can be stirred. The container can be pressurized by injecting an inert gas such as nitrogen gas. Moreover, you may utilize the raise of the vapor pressure of the solvent by heating. Or after sealing a container, you may add each component under pressure.
When heating, it is preferable to heat from the outside of the container. For example, a jacket type heating device can be used. Further, the entire container can be heated by providing a plate heater outside the container and piping to circulate the liquid.
It is preferable to provide a stirring blade inside the container and stir using this. The stirring blade preferably has a length that reaches the vicinity of the wall of the container. A scraping blade is preferably provided at the end of the stirring blade in order to renew the liquid film on the vessel wall.
Instruments such as a pressure gauge and a thermometer may be installed in the container. Each component is dissolved in a solvent in the container. The prepared dope is taken out of the container after cooling, or taken out and then cooled using a heat exchanger or the like.

The polymer solution (dope) may be prepared according to a cooling dissolution method. First, the polymer is gradually added to the organic solvent with stirring at a temperature around room temperature (-10 to 40 ° C.). When a plurality of solvents are used, the order of addition is not particularly limited. For example, after adding the polymer to the main solvent, another solvent (for example, a gelling solvent such as alcohol) may be added. It may be added and is effective in preventing non-uniform dissolution. The amount of the polymer is preferably adjusted so as to be contained in the mixture at 10 to 40% by mass.
The amount of the polymer is more preferably 10 to 30% by mass. Furthermore, you may add the arbitrary additive mentioned later in a mixture.

The mixture is then cooled to -100 to -10 ° C (preferably -80 to -10 ° C, more preferably -50 to -20 ° C, most preferably -50 to -30 ° C). The cooling can be performed, for example, in a dry ice / methanol bath (−75 ° C.) or a cooled diethylene glycol solution (−30 to −20 ° C.). Upon cooling in this way, the mixture of polymer and organic solvent solidifies. Although the cooling rate is not particularly limited, in the case of batch-type cooling, the viscosity of the polymer solution increases with cooling, and the cooling efficiency is inferior, so it is necessary to make an efficient melting pot to reach the predetermined cooling temperature It is.
In the cooling dissolution method, after the polymer solution is swollen, it may be transported in a short time in a cooling device having a predetermined cooling temperature. The faster the cooling rate, the better. However, 10,000 ° C./second is the theoretical upper limit, 1000 ° C./second is the technical upper limit, and 100 ° C./second is the practical upper limit. The cooling rate is a value obtained by dividing the difference between the temperature at the start of cooling and the final cooling temperature by the time from the start of cooling until the final cooling temperature is reached. Further, when this is heated to 0 to 200 ° C. (preferably 0 to 150 ° C., more preferably 0 to 120 ° C., most preferably 0 to 50 ° C.), a solution in which the polymer flows in the organic solvent is obtained. The temperature can be raised by simply leaving it at room temperature or in a warm bath.

A uniform solution is obtained as described above. If the dissolution is insufficient, the cooling and heating operations may be repeated. Whether or not the dissolution is sufficient can be determined by merely observing the appearance of the solution with the naked eye. In the cooling dissolution method, it is desirable to use a sealed container in order to avoid moisture mixing due to condensation during cooling. In the cooling and heating operation, when the pressure is applied during cooling and the pressure is reduced during heating, the dissolution time can be shortened. In order to perform pressurization and decompression, it is desirable to use a pressure-resistant container.
In addition, according to differential scanning calorimetry (DSC), a 20 mass% solution obtained by dissolving cellulose acetate (acetylation degree: 60.9%, viscosity average polymerization degree: 299) in methyl acetate by a cooling dissolution method was 33. There exists a quasi-phase transition point between a sol state and a gel state in the vicinity of ° C., and a uniform gel state is obtained below this temperature. Therefore, this solution needs to be stored at a temperature equal to or higher than the pseudo phase transition temperature, preferably about the gel phase transition temperature plus about 10 ° C. However, this pseudo phase transition temperature varies depending on the degree of acetylation of cellulose acetate, the degree of viscosity average polymerization, the concentration of the solution, and the organic solvent used.

  A polymer film is produced from the prepared polymer solution (dope) by a solvent cast method. Moreover, it is preferable to add the above-mentioned retardation increasing agent to the dope. The dope is cast on a drum or band and the solvent is evaporated to form a film. The dope before casting is preferably adjusted to have a solid content of 10 to 40%, more preferably 15 to 35%. The surface of the drum or band is preferably finished in a mirror state. Regarding casting and drying methods in the solvent cast method, U.S. Pat. Nos. 2,336,310, 2,367,603, 4,920,78, 2,429,297, 2,429,978, 2,607,704, 2,273,069, No. 2739070, British Patent Nos. 640731 and 736892, JP-B Nos. 45-4554, 49-5614, JP-A-60-176634, No. 60-203430, No. 62-11535 Are described in each publication. The dope is preferably cast on a drum or band having a surface temperature of 40 ° C. or lower. After casting, it is preferable to dry it by applying air for 2 seconds or more. The obtained film can be peeled off from the drum or band, and further dried by high-temperature air whose temperature is successively changed from 100 to 160 ° C. to evaporate the residual solvent. The above method is described in Japanese Patent Publication No. 5-17844. According to this method, it is possible to shorten the time from casting to stripping. In order to carry out this method, it is necessary for the dope to gel at the surface temperature of the drum or band during casting.

A plurality of polymer solutions may be cast, or a single material may be cast (co-cast) simultaneously at a plurality of casting ports. When casting a plurality of polymer solutions, it is possible to produce a film while casting and laminating a solution containing a polymer from a plurality of casting openings provided at intervals in the direction of travel of the support (special features). (Kaisho 61-158414, JP-A-1-122419, and JP-A-11-198285). A film can also be produced by casting a polymer solution from two casting ports (Japanese Patent Publication Nos. 60-27562, 61-94724, 61-947245, 61-104413, 61-158413 and JP-A-6-134933). Furthermore, a polymer film casting method (described in JP-A-56-162617) in which a flow of a high-viscosity polymer solution is wrapped with a low-viscosity polymer solution and the high- and low-viscosity polymer solutions are simultaneously extruded can be employed.
Using two casting ports, the film cast on the support is peeled off by the first casting port, and the second casting is performed on the side that was in contact with the support surface to produce a film. A method (described in Japanese Patent Publication No. 44-20235) can also be carried out. The plurality of polymer solutions may be the same solution. In order to give a plurality of polymer layers different functions, a polymer solution corresponding to the functions may be extruded from each casting port.

The polymer solution can be cast simultaneously with a coating solution for other functional layers (for example, an adhesive layer, a dye layer, an antistatic layer, an antihalation layer, a UV absorbing layer, and a polarizing layer).
In the conventional monolayer liquid, it is necessary to extrude a polymer solution having a high concentration and a high viscosity in order to obtain a necessary film thickness. In that case, the stability of the polymer solution is poor and solid matter is generated, which often causes problems due to defects or flatness. As a solution to this, by casting a plurality of polymer solutions from the casting port, it is possible to simultaneously extrude a highly viscous solution onto the support, and to improve the flatness and produce an excellent planar film. Furthermore, by using a concentrated polymer solution, it is possible to achieve a reduction in drying load and further increase the film production speed.

A plasticizer can be added to the polymer film in order to improve mechanical properties or increase the drying speed. As the plasticizer, phosphoric acid ester or carboxylic acid ester is used. Examples of phosphate esters include triphenyl phosphate (TPP) and tricresyl phosphate (TCP). Representative examples of the carboxylic acid ester include phthalic acid esters and citric acid esters. Examples of phthalic acid esters include dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP), diphenyl phthalate (DPP) and diethyl hexyl phthalate (DEHP). Examples of citrate esters include triethyl O-acetylcitrate (OACTE) and tributyl O-acetylcitrate (OACTB). Examples of other carboxylic acid esters include butyl oleate, methylacetyl ricinoleate, dibutyl sebacate, and various trimellitic acid esters. Phthalate plasticizers (DMP, DEP, DBP, DOP, DPP, DEHP) are preferably used. DEP and DPP are particularly preferred.
The addition amount of the plasticizer is preferably 0.1 to 25% by mass, more preferably 1 to 20% by mass, and most preferably 3 to 15% by mass of the amount of the polymer.

  A degradation inhibitor (eg, antioxidant, peroxide decomposer, radical inhibitor, metal deactivator, acid scavenger, amine) may be added to the polymer film. The deterioration preventing agents are described in JP-A-3-199201, JP-A-51907073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854. The addition amount of the deterioration preventing agent is preferably 0.01 to 1% by mass of the solution (dope) to be prepared, and more preferably 0.01 to 0.2% by mass. When the addition amount is less than 0.01% by mass, the effect of the deterioration preventing agent is hardly recognized. When the addition amount exceeds 1% by mass, bleed-out (bleeding) of the deterioration preventing agent to the film surface may be observed. Particularly preferred degradation inhibitors are butylated hydroxytoluene (BHT) and tribenzylamine (TBA).

The produced polymer film can further adjust the retardation by a stretching treatment. The draw ratio is preferably 3 to 100%. The thickness of the polymer film after stretching is preferably 20 to 200 μm, and more preferably 30 to 100 μm. By adjusting the conditions for the stretching treatment, the standard deviation of the slow axis angle of the optical compensation sheet can be reduced. The stretching process can be performed using a tenter. When the film produced by the solvent cast method is subjected to transverse stretching using a tenter, the standard deviation of the film slow axis angle can be reduced by controlling the state of the film after stretching. Specifically, the film is stretched by adjusting a retardation value using a tenter, and the polymer film immediately after stretching is stretched at a stretch ratio between the maximum stretch ratio and a stretch ratio of 1/2 of the maximum stretch ratio. By maintaining the temperature near the glass transition temperature, the standard deviation of the slow axis angle can be reduced. If the film temperature during this holding is lower than the glass transition temperature, the standard deviation will increase.
In addition, when performing longitudinal stretching between rolls, the standard deviation of the slow axis can be reduced by increasing the distance between the rolls.

When the polymer film functions as a transparent protective film for the polarizing film in addition to the function as a transparent support for the optical compensation sheet, it is preferable to subject the polymer film to a surface treatment.
As the surface treatment, corona discharge treatment, glow discharge treatment, flame treatment, acid treatment, alkali treatment or ultraviolet irradiation treatment is performed. An acid treatment or an alkali treatment is preferably performed, and an alkali treatment is more preferably performed. When the polymer is cellulose acetate, the acid treatment or alkali treatment is performed as a saponification treatment on cellulose acetate.

[Light diffusion layer]
In the present invention, by using a light diffusion layer on the viewing side surface, it is possible to suppress a change in luminance due to a viewing angle and further improve uniformity.
Light diffusion is realized by including translucent fine particles in, for example, a translucent resin, and by functioning in combination with the size, refractive index, and mixing of multiple particle types of translucent fine particles, Strength (haze), angle dependency (profile), and surface scattering / internal scattering ratio are adjusted. In the example of the present invention, it is preferable to use translucent fine particles having two or more kinds of particle diameters and / or materials in addition to using one kind of particles. As an example of a preferred embodiment, as shown in FIG. 1, two kinds of translucent fine particles are included. For example, the first translucent fine particles are made of crosslinked polystyrene beads (average particle size: 3.5 μm, refractive). The second translucent fine particles can be composed of silica fine particles (average particle diameter: 1.0 μm, refractive index: 1.51).
The light diffusion function is the difference in refractive index between the light-transmitting fine particles and the light-transmitting resin that constitutes the entire light diffusion layer (if inorganic fine particles are added to adjust the refractive index of the light diffusion layer, the light It is obtained by the difference between the optical average refractive index of the diffusion layer and the refractive index of the translucent fine particles. The difference in refractive index is preferably 0.03 to 0.30, more preferably 0.06 to 0.25, and most preferably 0.09 to 0.20.
The peak of the particle size distribution of the first light-transmitting fine particles (larger particles) is preferably in the range of 2.5 to 10 μm. The peak of the particle size distribution of the second light transmitting fine particles (smaller particles) is preferably in the range of 0.5 to 3.5 μm. A preferable particle size distribution can be easily realized by mixing two types of fine particle groups having different mode particle sizes.

  With the second light-transmitting fine particles (smaller particles), an optimal angle distribution of light scattering can be obtained. In order to improve display quality (improve visual field characteristics), it is necessary to diffuse incident light to some extent. The greater the diffusion effect, the better the viewing angle characteristics. However, in order to maintain the front brightness in terms of display quality, it is necessary to increase the transmittance as much as possible. By adjusting the peak of the particle size to 0.5 μm or more, the backscattering can be reduced and the decrease in brightness can be suppressed. In addition, by setting the particle size peak to 2.0 μm or less, a large scattering effect is obtained, and the viewing angle characteristics are improved. The peak of the particle size distribution of the second translucent fine particles (smaller particles) is more preferably in the range of 0.6 to 1.8 μm, and more preferably in the range of 0.7 to 1.6 μm. Most preferred.

Optimal surface scattering can be obtained by the first light-transmitting fine particles (larger particles). In order to improve display quality, it is also important to prevent external light from being reflected by appropriate surface scattering. Therefore, the peak of the particle size distribution of the first translucent fine particles (larger particles) is adjusted to a range of 2.5 to 10 μm.
The lower the haze value of the surface, the smaller the decrease in contrast due to external light, and a clear display can be obtained. However, if the haze value is too low, the reflection is increased, so that it is necessary to provide a low refractive index layer on the outermost layer (viewing side) or to reduce the reflectance.
In order to control the surface haze value, it is preferable to provide appropriate irregularities on the surface of the resin layer with the first light-transmitting fine particles (larger particles). The haze value (cloudiness value) can be measured using HR-100 manufactured by Murakami Color Research Laboratory according to JIS-K-7136.
When the particle diameter is 2.5 μm or less, in order to provide a desired surface irregularity, the thickness of the layer has to be reduced, and it is difficult to achieve a balance with the film strength. On the other hand, when the thickness is 10.0 μm or more, the mass of the mixed particles becomes large, and it is easy to settle in the coating solution, which is not preferable. Further, the surface unevenness is increased, and the reflection is suppressed, but it is markedly whitened and the display quality is lowered. The peak of the particle size distribution of the first translucent fine particles (larger particles) is preferably 2.7 μm to 9.0 μm, and most preferably 3.0 μm to 8.0 μm.

As described above, the mode particle size is more important than the average particle size as the particle size of the fine particles. In the present specification, the mode particle size means a particle size in which fine particles are classified by particle size (0.1 μm unit) and the maximum number of fine particles is classified. The particle size of the fine particles described below (including the examples) means the mode particle size.
The surface unevenness is preferably 0.5 μm or less, more preferably 0.3 μm or less, and most preferably 0.2 μm or less as an average surface roughness (Ra).

The haze value of the light diffusion layer, particularly the internal scattering haze that greatly contributes to the diffusion of transmitted light, has a strong correlation with the viewing angle improvement effect.
Viewing angle characteristics are improved by the light emitted from the backlight being diffused by the light diffusion layer provided on the polarizing plate surface on the viewing side. If diffused too much, backscattering will increase and front brightness will decrease. Alternatively, there is a problem that image clarity is deteriorated due to excessive scattering. Therefore, the internal scattering haze of the light diffusion layer is preferably 45% or more and 80% or less, more preferably 45% or more and 70% or less, and particularly preferably 45% or more and 60% or less.
As a method for increasing the internal scattering haze, there are methods such as increasing the concentration of particles having a particle size of 0.5 μm to 3.5 μm, increasing the film thickness, and further increasing the refractive index difference between the particles and the resin. is there.

The translucent fine particles are preferably plastic beads. It is desirable to adjust the difference in refractive index from the translucent resin as described above by using a plastic with high transparency. Plastic beads include acrylic-styrene copolymer beads (refractive index: 1.55), melamine resin beads (refractive index: 1.57), cross-linked acrylic resin beads (refractive index: 1.49), polycarbonate beads (refractive Ratio: 1.57), polystyrene beads (refractive index: 1.60), crosslinked polystyrene beads (refractive index: 1.61) and polyvinyl chloride beads (refractive index: 1.60). Examples of the first light-transmitting fine particles (larger particles) include MX300 (crosslinked PMMA 3 μm), MX500 (crosslinked PMMA 5 μm), MX800 (crosslinked PMMA 8 μm), and SX350H (crosslinked polystyrene). 5 μm), SX500H (cross-linked polystyrene 5.0 μm), Sekisui Chemical SBX-8 (cross-linked polystyrene 8.0 μm), SBX-6 (cross-linked polystyrene 6.0 μm), and the second translucent fine particles (small) Examples of such particles include MX130 (cross-linked PMMA 1.3 μm) and SX130H (cross-linked polystyrene 1.3 μm) manufactured by Soken Chemical Co., Ltd., but are not limited thereto.
Inorganic fine particles may be used as the translucent resin. Examples of the inorganic fine particles include silica beads (refractive index: 1.44) and alumina beads (refractive index: 1.63).
The translucent fine particles are preferably used in an amount of 5 to 30 parts by mass with respect to 100 parts by mass of the translucent resin.

  The translucent fine particles are likely to settle in the resin composition (translucent resin). In order to prevent sedimentation, an inorganic filler (eg, silica) may be added. In addition, an inorganic filler may have a bad influence on the transparency of a coating film. Therefore, in order not to impair the transparency of the coating film, it is desirable that the particle size of the inorganic filler is 0.5 μm or less and the addition amount is less than 0.1 mass% with respect to the translucent resin.

  In order to improve display quality (improve viewing angle characteristics) in the present invention, it is particularly preferable that the scattered light intensity of 30 ° with respect to the light intensity of the output angle 0 ° of the scattered light profile of the goniophotometer is within a specific range. . The scattered light intensity of 30 ° with respect to the light intensity of the output angle 0 ° of the scattered light profile of the goniophotometer is preferably 0.05 to 0.3%, and more preferably 0.07 to 0.2%. More preferably, it is 0.09 to 0.16%. It is more preferable to satisfy the above preferable range of the internal haze.

  The haze due to surface scattering of the polarizing plate of the present invention (surface haze) is 0.1 to 30%, preferably 10% or less, and preferably 5% or less, from the viewpoint of achieving both reduction in reflection and reduction in white-brown feeling. Particularly preferred. If importance is attached to the reduction of white-brown feeling due to external light, it is preferably 4% or less, and more preferably 2% or less. Since reflection increases when surface haze is reduced, a low refractive index layer is provided, and it is preferable that the average value in the wavelength region from 450 nm to 650 nm of the integrated reflectance at 5 ° incidence be 3.0% or less, It is more preferably 2.0% or less, and most preferably 1.0% or less. In order to improve display quality (improve viewing angle characteristics) in the present invention, it is necessary to adjust the internal scattering property as described above. At the same time, by setting the surface haze and / or reflectivity within a suitable range, The contrast is improved and the most preferable effect can be exhibited. The translucent resin used for the light diffusion layer is preferably a resin that is cured by ultraviolet rays or electron beams. A thermosetting resin can also be used. A thermoplastic resin and a solvent may be mixed in the resin.

  As the translucent resin, there are three types of resins that are mainly cured by ultraviolet rays and electron beams, that is, an ionizing radiation curable resin, a mixture of an ionizing radiation curable resin and a thermoplastic resin and a solvent, and a thermosetting resin. Is done. In order to impart hard coat properties, an ionizing radiation curable resin is preferably the main component. The thickness of the light diffusion layer is usually 1.5 μm to 30 μm, preferably 3 μm to 20 μm. In general, the light diffusing layer also functions as a hard coat layer. However, when the thickness of the light diffusing layer becomes thinner than 1.5 μm, the hard coat property is not sufficient, whereas from 30 μm If the thickness is too thick, this is an undesirable direction in terms of curling and brittleness. When providing the low refractive index layer, the refractive index of the translucent resin is preferably 1.46 to 2.00, more preferably 1.48 to 1.90, and further preferably 1.50. 1.80. The refractive index of the translucent resin is an average value of the light diffusion layer measured without including the translucent fine particles. When the refractive index of the light diffusing layer is too small, the antireflection property is lowered. If it is too large, the color of the reflected light becomes strong, which is not preferable. From this point, the above range is preferable. The refractive index of the light diffusion layer is set to a desired value in terms of antireflection properties and reflected light color. The translucent resin preferably contains, as a binder, a polymer having a saturated hydrocarbon or polyether as a main chain. More preferably, the polymer has a saturated hydrocarbon as the main chain. The polymer is preferably crosslinked. The polymer having a saturated hydrocarbon as the main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked polymer, it is preferable to use a monomer having two or more ethylenically unsaturated groups.

Examples of monomers having two or more ethylenically unsaturated groups include esters of polyhydric alcohols and (meth) acrylic acid (eg, ethylene glycol di (meth) acrylate, 1,4-dichlorohexane diacrylate, penta Erythritol tetra (meth) acrylate), pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) Acrylate, dipentaerythritol hexa (meth) acrylate, 1,3,5-cyclohexanetriol trimethacrylate, polyurethane polyacrylate, polyester polyacrylate), derivatization of vinylbenzene (Examples: 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester, 1,4-divinylcyclohexanone), vinylsulfone (eg: divinylsulfone), acrylamide (eg: methylenebisacrylamide) and methacrylamide Is included. A pentafunctional or higher functional acrylate is preferable because it can form a layer having excellent film hardness, that is, scratch resistance. A mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate is commercially available and is particularly preferably used.
The monomer having an ethylenically unsaturated group can be cured by a polymerization reaction by ionizing radiation or heat after being dissolved in a solvent together with various polymerization initiators and other additives, applied and dried.

Instead of or in addition to the use of a monomer having two or more ethylenically unsaturated groups, a crosslinked structure may be introduced into the binder by reaction of the crosslinkable group. Examples of the crosslinkable functional group include isocyanate group, epoxy group, aziridine group, oxazoline group, aldehyde group, carbonyl group, hydrazine group, carboxyl group, methylol group and active methylene group. Vinyl sulfonic acid, acid anhydride, cyanoacrylate derivative, melamine, etherified methylol, ester, urethane, and metal alkoxide (eg, tetramethoxysilane) can also be used as a monomer for introducing a crosslinked structure. A functional group that exhibits crosslinkability as a result of the decomposition reaction, such as a block isocyanate group, may be used. That is, the crosslinkable functional group does not show reactivity as it is, and may show reactivity as a result of decomposition.
A polymer having a crosslinkable functional group can form a crosslinked structure by heating after coating.

In addition to the above polymer, the light-transmitting resin binder can be formed from a polymer obtained by copolymerization of a monomer having a high refractive index or metal oxide ultrafine particles having a high refractive index. Examples of high refractive index monomers include bis (4-methacryloylthiophenyl) sulfide, vinyl naphthalene, vinyl phenyl sulfide and 4-methacryloxyphenyl-4′-methoxyphenyl thioether.
In the example of the metal oxide ultrafine particles having a high refractive index, the particle size is preferably 100 nm or less, and more preferably 50 nm or less. The metal of the metal oxide is preferably zirconium, titanium, aluminum, indium, zinc, tin or antimony. Examples of metal _{oxides, ZrO 2, TiO 2, Al} 2 O 3, In 2 O 3, ZnO, is SnO _2, Sb ₂ O _3, and ITO is contained. ZrO ₂ is particularly preferred. The addition amount of the metal oxide ultrafine particles is preferably 10 to 90% by mass of the translucent resin, and more preferably 20 to 80% by mass.

The light diffusion layer is preferably formed on the cellulose acetate film by coating. Usually, a light diffusion layer can be formed by direct coating on the second transparent protective film made of a cellulose acetate film. You may form a light-diffusion layer on the cellulose acetate film different from a 2nd transparent protective film, and adhere | attach it with a 2nd transparent protective film.
When the light diffusion layer is formed on the cellulose acetate film, it is necessary to mix and use two types of solvents, a solvent that dissolves cellulose acetate and a solvent that does not dissolve cellulose acetate, in the coating solution of the light diffusion layer. Particularly preferred. It is more preferable that the solvent (at least one of them) that dissolves cellulose acetate has a higher boiling point than the solvent (at least one of them) that does not dissolve cellulose acetate. More preferably, the difference between the boiling point of the solvent that does not dissolve the cellulose acetate (the highest when there are several kinds) and the boiling point of the solvent that does not dissolve the cellulose acetate (the highest when there are several kinds) is 30 ° C. or more. Most preferably, it is 40 ° C or higher.

  Examples of solvents for dissolving cellulose acetate include ethers having 2 to 12 carbon atoms (eg, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane). 1,3,5-trioxane, tetrahydrofuran, anisole, phenetole), ketones having 3 to 12 carbon atoms (eg, acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methylcyclohexanone) , Methylcyclohexanone), esters having 1 to 12 carbon atoms (eg, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, n-pentyl acetate, methyl propio) Organic solvents having two or more types of functional groups (eg, methyl 2-methoxyacetate, methyl 2-ethoxyacetate, ethyl 2-ethoxyacetate, ethyl 2-ethoxypropio) Nate, 2-methoxyethanol, 2-propoxyethanol, 2-butoxyethanol, 1,2-diacetoxyacetone, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate). Two or more organic solvents may be used in combination.

Examples of solvents that do not dissolve cellulose acetate include alcohols (eg, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-methyl-2- Butanol, cyclohexanol), ester (eg, isobutyl acetate), ketone (eg, methyl isobutyl ketone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-pentanone, 3-heptanone, 4-heptanone) And toluene. Two or more organic solvents may be used in combination.
The mass ratio (A / B) of the total amount (A) of the solvent that dissolves the cellulose acetate and the total amount (B) of the solvent that does not dissolve the cellulose acetate is preferably 5/95 to 50/50, and 10/90 to 40 / 60 is more preferable, and 15/85 to 30/70 is most preferable.

The light diffusion layer is preferably cured by irradiation with an electron beam or ultraviolet light after application of the coating solution.
In the case of electron beam curing, an electron beam emitted from an electron beam accelerator can be used. The electron beam energy is preferably 50 to 1000 KeV, more preferably 100 to 300 KeV. As the electron beam accelerator, a Cochlowalton type, a bandegraph type, a resonance transformer type, an insulated core transformer type, a linear type, a dynamitron type, or a high frequency type can be used. In the case of ultraviolet curing, an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a carbon arc, a xenon arc, or a metal halide lamp can be used as an ultraviolet light source.

[Low refractive index layer]
In the present invention, the object of the present invention can be achieved by providing at least one light diffusing layer in the range described above, but the refractive index lower than the refractive index of the layer adjacent to the outermost layer. By coating the layer with an appropriate thickness, antireflection performance can be obtained, reflection of external light can be suppressed, and contrast in a bright room environment can be increased. This is preferable.

The material for forming the low refractive index layer is described below.
The low refractive index layer of the present invention is formed by applying and curing a curable composition containing a fluorine-containing compound as a main component or a monomer having a plurality of bonding groups in the molecule and low refractive index particles. Thus, the refractive index is adjusted in the range of 1.20 to 1.50. 1.25 to 1.45 are preferred. More preferably 1.30 to 1.40.
Preferred embodiments of the cured product composition include (1) a composition containing a fluorine-containing polymer having a crosslinkable or polymerizable functional group, and (2) a hydrolysis condensate of a fluorine-containing organosilane material as a main component. Composition, (3) a composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure, thereby comparing with a low refractive index layer using magnesium fluoride or calcium fluoride Even when used as the outermost layer, an optical film excellent in scratch resistance can be obtained. The dynamic friction coefficient of the cured low refractive index layer surface is preferably 0.03 to 0.15, and the contact angle with water is preferably 90 to 120 degrees.

(1) Fluorine-containing compound having a crosslinkable or polymerizable functional group As the fluorine-containing compound having a crosslinkable or polymerizable functional group, co-polymerization of a fluorine-containing monomer and a monomer having a crosslinkable or polymerizable functional group Coalescence can be mentioned. Examples of the fluorine-containing monomer include fluoroolefins (for example, fluoroethylene, vinylidene fluoride, tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoro-2,2-dimethyl-1,3-dioxole, etc.) (meta ) Acrylic acid partial or fully fluorinated alkyl ester derivatives (for example, Biscoat 6FM (manufactured by Osaka Organic Chemicals) and M-2020 (manufactured by Daikin)), fully or partially fluorinated vinyl ethers, and the like.

  As an example of the monomer for imparting a crosslinkable group, a (meth) acrylate monomer having a crosslinkable functional group in the molecule in advance such as glycidyl methacrylate can be exemplified. In another embodiment, after synthesizing a fluorinated copolymer using a monomer having a functional group such as a hydroxyl group, the monomer is further modified to introduce a crosslinkable or polymerizable functional group by modifying the substituent. It is. These monomers include (meth) acrylate monomers having a carboxyl group, hydroxyl group, amino group, sulfonic acid group, etc. (for example, (meth) acrylic acid, methylol (meth) acrylate, hydroxyalkyl (meth) acrylate, allyl acrylate, etc.) Is mentioned. The latter embodiment is disclosed in Japanese Patent Laid-Open Nos. 10-25388 and 10-147739.

From the viewpoints of solubility, dispersibility, coatability, antifouling property, antistatic property and the like, the fluorine-containing copolymer can contain a copolymerizable component as appropriate. In particular, for imparting antifouling properties and slipperiness, it is preferable to introduce silicone, and it can be introduced into both the main chain and the side chain.
The polysiloxane partial structure introduction method to the main chain is, for example, an azo group-containing polysiloxane amide described in JP-A-6-93100 (VPS-0501, 1001 (trade name; Wako Pure Chemical Industries, Ltd. And a method using a polymer-type initiator such as a company)). Moreover, the method of introduce | transducing into a side chain is J. for example. Appl. Polym. Sci. As described in 2000, 78, 1955, JP-A-56-28219, etc., a polysiloxane having a reactive group at one end (for example, Silaplane series (manufactured by Chisso Corporation)) is introduced by a polymer reaction. The method can be synthesized by a method of polymerizing a polysiloxane-containing silicon macromer, and both methods can be preferably used.

As described in JP 2000-17028 A, a curing agent having a polymerizable unsaturated group may be used in combination with the above polymer. Moreover, combined use with the compound which has a fluorine-containing polyfunctional polymerizable unsaturated group as described in Unexamined-Japanese-Patent No. 2002-145952 is also preferable. Examples of the compound having a polyfunctional polymerizable unsaturated group include the above-described monomers having two or more ethylenically unsaturated groups. Moreover, the hydrolysis-condensation product of the organolane described in Unexamined-Japanese-Patent No. 2004-170901 is also preferable, and the hydrolysis-condensation product of the organosilane containing a (meth) acryloyl group is especially preferable.
These compounds are particularly preferred because they have a large combined effect for improving scratch resistance, particularly when a compound having a polymerizable unsaturated group is used in the polymer body.

  When the polymer itself does not have sufficient curability, necessary curability can be imparted by blending a crosslinkable compound. For example, when the polymer body contains a hydroxyl group, various amino compounds are preferably used as the curing agent. The amino compound used as the crosslinkable compound is, for example, a compound containing one or both of a hydroxyalkylamino group and an alkoxyalkylamino group in total, specifically, for example, a melamine compound, Examples include urea compounds, benzoguanamine compounds, glycoluril compounds, and the like. For curing these compounds, an organic acid or a salt thereof is preferably used.

Specific examples of these fluoropolymers are described in JP2003-222702A, JP2003-183322A, and the like.

(2) Hydrolyzed condensate of fluorine-containing organosilane material A composition containing a hydrolyzed condensate of a fluorine-containing organosilane compound as a main component is also preferable because of its low refractive index and high hardness on the coating film surface. A condensate of a tetraalkoxysilane with a hydrolyzable silanol-containing compound at one or both ends with respect to the fluorinated alkyl group is preferred. The specific composition is described in Unexamined-Japanese-Patent No. 2002-265866, 317152.

(3) A composition containing a monomer having two or more ethylenically unsaturated groups and inorganic fine particles having a hollow structure As yet another preferred embodiment, a low refractive index layer comprising low refractive index particles and a binder can be mentioned. . The low refractive index particles may be organic or inorganic, but particles having pores inside are preferable. Specific examples of the hollow particles are described in the silica-based particles described in JP-A-2002-79616. The particle refractive index is preferably 1.15 to 1.40, more preferably 1.20 to 1.30. Examples of the binder include monomers having two or more ethylenically unsaturated groups described in the page of the light diffusion layer.

  It is preferable to add the polymerization initiator described in the page of the light scattering layer to the low refractive index layer of the present invention. When a radically polymerizable compound is contained, 1 to 10 parts by mass, preferably 1 to 5 parts by mass of a polymerization initiator can be used with respect to the compound.

  In the low refractive layer of the present invention, inorganic particles can be used in combination. In order to impart scratch resistance, fine particles having a particle size of 15% to 150%, preferably 30% to 100%, more preferably 45% to 60% of the thickness of the low refractive index layer can be used. .

  In the low refractive index layer of the present invention, for the purpose of imparting properties such as antifouling property, water resistance, chemical resistance, and slipping property, a known polysiloxane-based or fluorine-based antifouling agent, slipping agent, etc. are appropriately used. Can be added.

The film having the light diffusing layer of the present invention has a vertical peeling charge of −200 pC (picocoulomb) / cm ² to +200 pC (measured at normal temperature and humidity) with respect to either triacetyl cellulose (TAC) or polyethylene terephthalate (PET). Picocoulomb) / cm ² is preferable. More preferably, it is −100 pC / cm to +100 pC / cm ² , further preferably −50 pC / cm ² to +50 pC / cm ² , and most preferably 0 pC / cm ² . Here, the unit of pC (picocoulomb) is 10 ⁻¹² coulomb. More preferably, the vertical peel charge measured at room temperature of 10% RH is −200 pC / cm ² to +200 pC / cm ² , more preferably −50 pC / cm ² to +50 pC / cm ² , most preferably 0 pC / cm ^{2. 2} .

  The measurement method of the vertical peeling charge is as follows. The measurement sample is left in advance for 2 hours or more in an environment of measurement temperature and humidity. The measuring device is composed of a table on which a measurement sample is placed and a head that can hold a partner film and repeatedly press and peel the measurement sample from above, and an electrometer for measuring the charge amount is connected to the head. An antiglare antireflection film to be measured is placed on a table, and TAC or PET is attached to the head. After neutralizing the measurement portion, the head is pressure-bonded to the measurement sample and peeled off repeatedly, and the charge values at the first peeling and the fifth peeling are read and averaged. This is repeated for three samples by changing the sample, and the average of all the samples is defined as vertical peeling charge.

Surface resistivity of a film having a diffusion layer of the present invention is preferably 1 × 10 ⁷ Ω / □ or more 1 × 10 ¹⁵ Ω / □ or less, 1 × 10 ⁷ Ω / □ or more 1 × 10 ¹⁴ Ω / □ or less More preferably, it is 1 × 10 ⁷ Ω / □ or more and 1 × 10 ¹³ Ω / □ or less.
The measuring method of the surface resistance value is a circular electrode method described in JIS. That is, the current value one minute after voltage application is read to determine the surface resistance value (SR).

In order to reduce the surface resistance value, it is preferable to provide an antistatic layer. A preferred layer structure is shown below.
• Base film / light diffusion layer / antistatic layer / low refractive index layer • Base film / antistatic layer / light diffusion layer / low refractive index layer • Base film / light diffusion layer (antistatic layer) / low refraction Index layer / base film / light diffusion layer / medium refractive index layer (antistatic layer) / high refractive index layer / low refractive index layer,
Base film / light diffusion layer (antistatic layer) / medium refractive index layer / high refractive index layer / low refractive index layer,
Base film / antistatic layer / light diffusion layer / medium refractive index layer / high refractive index layer / low refractive index layer,
Base film / light scattering layer / medium refractive index layer / high refractive index layer (antistatic layer) / low refractive index layer Note that the low refractive index layer may not be provided, and is not limited to the above configuration. . The antistatic layer is preferably a layer containing conductive polymer particles or metal oxide fine particles (for example, ATO, ITO), and can be provided by coating or atmospheric pressure plasma treatment. When providing an antifouling layer, it can be provided in the uppermost layer of the above-mentioned configuration.

Further, in order to increase the film hardness (for imparting scratch resistance), in addition to thickening the light diffusion layer having hard coat properties described in the present invention, a hard coat layer (invention) It is also preferable to provide at least one layer with or without light diffusibility. The preferred layer structure is as follows.
-Base film / hard coat layer / light diffusion layer / low refractive index layer-Base film / light diffusion layer / hard coat layer / low refractive index layer Note that the low refractive index layer may not be provided, and It is not limited to the configuration. Furthermore, it is also preferable to combine the antistatic layer.

  The average value of the integrated reflectance of the film having the diffusion layer of the present invention in the wavelength region from 450 nm to 650 nm at 5 ° incidence is preferably 3.0% or less, more preferably 2.0% or less, and most preferably 1.0% or less.

[Polarizing film]
Examples of the polarizing film include an iodine polarizing film, a dye polarizing film using a dichroic dye, and a polyene polarizing film. The iodine polarizing film and the dye polarizing film are generally produced using a polyvinyl alcohol film. The slow axis of the polymer film and the transmission axis of the polarizing film are preferably substantially parallel. Specifically, the angle between the slow axis and the transmission axis is preferably 3 ° or less, more preferably 2 ° or less, and more preferably 1 ° or less. Most preferably.

[Liquid Crystal Cell]
The present invention is particularly effective in a liquid crystal display device using a bend alignment liquid crystal cell.
In the bend alignment liquid crystal cell, the liquid crystal molecules at the center of the cell may be twisted.
In the bend alignment liquid crystal cell, the product (Δn × d) of the refractive index anisotropy Δn of the liquid crystal compound and the thickness d of the liquid crystal layer of the liquid crystal cell is 100 to 2000 nm in order to achieve both luminance and viewing angle. The range is preferably 150 to 1700 nm, and more preferably 500 to 1500 nm.
In order to shorten the response time, it is preferable to reduce the cell gap. Specifically, it is preferably 10 μm or less, more preferably 6 μm or less, and most preferably 4 μm or less. In order to reduce the cell gap, it is preferable to increase Δn of the liquid crystal compound. However, if Δn is excessively increased, the wavelength dispersion of Δn becomes excessively large and affects the display color. Therefore, it is preferable to increase Δn within an appropriate range. Specifically, 0.05 to 0.5 is preferable, and 0.1 to 0.3 is more preferable.
The upper limit of the drive voltage (black display voltage in the normally white mode) is preferably lowered in order to suppress the consumed output. From the viewpoint of the cost of the driver IC, it is preferable that the driver IC can be driven in a voltage range that can be handled by a general-purpose driver IC. Specifically, it is preferable that the signal level input to the source wiring can be driven at 15 V or less, and it is more preferable that the signal level can be driven at 10 V or less.
The tilt angle at the alignment film interface of the liquid crystal molecules is preferably in the range of 0 ° to 20 °, more preferably 3 ° to 15 °, and more preferably 5 ° to 15 ° in order to achieve both driving voltage and luminance. Most preferably, it is 10 °.

In order to perform active driving, any of amorphous silicon TFT, high-temperature polysilicon TFT, and low-temperature polysilicon TFT can be used. In order to form an aperture ratio improvement, high definition, driver IC, memory circuit, etc. on a glass substrate, it is preferable to use a low-temperature polysilicon TFT.
In order to suppress blur (tailing) in moving image display, it is preferable to perform driving (described on page 63 of AM-LCD'01) to insert black display during white display. Further, a display method for intermittent display of the backlight (described on page 67 of AM-LCD'01) is also preferable.
The bend alignment liquid crystal cell can be used in a normally white mode (NW mode) or a normally black mode (NB mode).
As the liquid crystal mode, in addition to the bend alignment mode, a liquid crystal mode having a hybrid alignment in a voltage application state such as a TN alignment mode or a homogeneous alignment mode can be used.
A transflective display (described on page 55 of AM-LCD '01) may be performed so that it can be used in either a bright room environment or a dark room environment.

<Formation of light diffusion layer>
(Preparation of translucent fine particle dispersion A)
As translucent fine particles, acrylic (PMMA) cross-linked fine particles MXS300 obtained by dispersion polymerization without using a macromonomer as a dispersion stabilizer (Soken Chemical Co., Ltd., amount of cross-linking agent 5 mass%, 3.11 μm) It was used. 7.5 parts by mass of acrylic cross-linked fine particle MXS300 is added to 17.5 parts by mass of methyl isobutyl ketone, polytron dispersion is performed under the conditions of a rotational speed of 5000 rpm and a dispersion time of 3 hours, and the translucent fine particles of 30% by mass solution Dispersion A was obtained. The average particle size was measured using a master sizer manufactured by MALVERN, and methyl isobutyl ketone was used as a measurement solvent. The average particle size was 3.4 μm.

(Preparation of translucent fine particle dispersion B)
Silica fine particles KEP150 (Nippon Shokubai Co., Ltd., 1.56 μm) were used as the translucent fine particles. 7.5 parts by mass of silica fine particle KEP150 is added to 17.5 parts by mass of methyl ethyl ketone, polytron dispersion is performed under the conditions of a rotational speed of 5000 rpm and a dispersion time of 3 hours, and a 30% by mass translucent fine particle dispersion B is prepared. Obtained. The average particle size was measured using a master sizer manufactured by MALVERN, and methyl isobutyl ketone was used as a measurement solvent. The average particle size was 1.5 μm.

(Preparation of translucent fine particle dispersion C)
As translucent fine particles, acrylic (PMMA) crosslinked fine particles SBX-8 (Sekisui Chemical Co., Ltd., 8 μm) obtained by dispersion polymerization without using a macromonomer as a dispersion stabilizer was used. 7.5 parts by mass of SBX-8 is added to 17.5 parts by mass of cyclohexane, polytron dispersion is performed under the conditions of a rotational speed of 5000 rpm and a dispersion time of 3 hours, and a 30% by mass translucent fine particle dispersion A is obtained. Obtained. The average particle diameter was measured using a master sizer manufactured by MALVERN, and cyclohexane was used as a measurement solvent. The average particle size was 8.0 μm.

(Adjustment of translucent fine particle dispersion D)
As translucent fine particles, acrylic (PMMA) crosslinked fine particles SX-130 (Soken Chemical Co., Ltd., 1.3 μm) obtained by dispersion polymerization without using a macromonomer as a dispersion stabilizer were used. 7.5 parts by mass of acrylic crosslinked fine particles SX-130 are added to 17.5 parts by mass of cyclohexane, and polytron dispersion is performed under the conditions of a rotational speed of 5000 rpm and a dispersion time of 3 hours. Dispersion A was obtained. The average particle diameter was measured using a master sizer manufactured by MALVERN, and cyclohexane was used as a measurement solvent. The average particle size was 1.3 μm.

(Adjustment of coating solution for light diffusion layer)
────────────────────────────────────────
Coating solution A for light diffusion layer
────────────────────────────────────────
DPHA (dipentaerythritol pentaacrylate,
Mixture of dipentaerythritol hexaacrylate: Nippon Kayaku Co., Ltd.) 31.2 parts by mass Z7404 (Zirconia fine particle-containing hard coat composition: JSR Co., Ltd.) 101.3 parts by mass Translucent fine particle dispersion A 12 .3 parts by weight Translucent fine particle dispersion B 28.8 parts by weight KBM-5103 (silane coupling agent: manufactured by Shin-Etsu Chemical Co., Ltd.) 10.4 parts by weight Methyl ethyl ketone 9.4 parts by weight Methyl isobutyl ketone 6.6 Mass part ─────────────────────────────────────────

A coating solution A for light diffusion layer having the above composition was prepared.
The light diffusion layer coating solution A was applied to a commercially available cellulose triacetate film (Fujitac TD80U, manufactured by Fuji Photo Film Co., Ltd.) at 8.6 ml / m ² . After drying the solvent, using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) of 160 W / cm, the coating layer was irradiated by irradiating ultraviolet rays with an illuminance of 140 mW / cm ² and an irradiation amount of 100 mJ / cm ² under a nitrogen purge. Cured. Thus, the light diffusion layer A was formed.

──────────────────────────
Coating liquid B for light diffusion layer
──────────────────────────
DPHA 31.8 parts by weight Z7404 101.3 parts by weight Translucent fine particle dispersion A 12.3 parts by weight Translucent fine particle dispersion B 22.3 parts by weight KBM-5103 10.6 parts by weight Methyl ethyl ketone 13.9 parts by weight Methyl isobutyl ketone 5.9 parts by mass──────────────────────────
Using the light diffusion layer coating liquid B having the above composition, a light diffusion layer B was formed in the same manner as the light diffusion layer A and wound up.

──────────────────────────
Coating liquid C for light diffusion layer
──────────────────────────
DPHA 32.5 parts by weight Z7404 105.6 parts by weight Translucent fine particle dispersion A 12.3 parts by weight Translucent fine particle dispersion B 14.4 parts by weight KBM-5103 10.6 parts by weight Methyl ethyl ketone 19.3 parts by weight Methyl isobutyl ketone 5.1 parts by mass ──────────────────────────
Using the light diffusion layer coating liquid C having the above composition, a light diffusion layer C was formed in the same manner as the light diffusion layer A, and wound.

──────────────────────────
Coating liquid D for light diffusion layer
──────────────────────────
DPHA 33.2 parts by weight Z7404 107.9 parts by weight Translucent fine particle dispersion A 12.3 parts by weight Translucent fine particle dispersion B 6.5 parts by weight KBM-5103 11.1 parts by weight Methyl ethyl ketone 24.8 parts by weight Methyl isobutyl ketone 4.3 parts by mass──────────────────────────
Using the light diffusion layer coating liquid D having the above composition, a light diffusion layer D was formed in the same manner as the light diffusion layer A, and wound.

──────────────────────────
Coating liquid E for light diffusion layer
──────────────────────────
DPHA 33.8 parts by weight Z7404 109.7 parts by weight Translucent fine particle dispersion A 12.3 parts by weight KBM-5103 11.3 parts by weight Methyl ethyl ketone 29.3 parts by weight Methyl isobutyl ketone 3.7 parts by weight ──────────────────────
Using the light diffusion layer coating liquid E having the above composition, the light diffusion layer E was formed in the same manner as the light diffusion layer A and wound up.

──────────────────────────
Coating liquid F for light diffusion layer
──────────────────────────
DPHA 14.8 parts by weight PET-30 133.1 parts by weight Translucent fine particle dispersion C 7.7 parts by weight Translucent fine particle dispersion D 18.0 parts by weight Irgacure 184 6.0 parts by mass Irgacure 907 1 .1 part by weight FZ2191 0.2 part by weight Toluene 133.5 parts by weight Cyclohexane 39.2 parts by weight ──────────────────────────
PET-30; manufactured by Nippon Kayaku Co., Ltd. (a mixture of pentaerythritol triacrylate and pentaerythritol pentaacrylate)
FZ2191; Nihon Unicar Co., Ltd. (silicone leveling agent)
Using the light diffusion layer coating solution F having the above composition, a light diffusion layer E was formed in the same manner as the light diffusion layer A, and wound.

<Formation of low refractive index layer>
(Preparation of sol solution)
A stirrer, a reactor equipped with a reflux condenser, 120 parts by mass of methyl ethyl ketone, 100 parts by mass of acryloyloxypropyltrimethoxysilane (KBM5103 (trade name); manufactured by Shin-Etsu Chemical Co., Ltd.), 3 parts by mass of diisopropoxyaluminum ethyl acetoacetate After adding and mixing, 30 parts by mass of ion-exchanged water was added and reacted at 60 ° C. for 4 hours, and then cooled to room temperature to obtain a sol solution. The mass average molecular weight was 1800, and among the components higher than the oligomer component, the component having a molecular weight of 1000 to 20000 was 100%. Further, from the gas chromatography analysis, the raw material acryloyloxypropyltrimethoxysilane did not remain at all.

(Adjustment of coating solution for low refractive index layer)
───────────────────────────────────────
Coating liquid A for low refractive index layer
───────────────────────────────────────
JTA-113 (thermally crosslinkable, fluorine-containing polymer solution containing a silicone moiety, refractive index 1.44, solid content concentration 6% by mass, solvent methyl ethyl ketone: manufactured by JSR Corporation) 13.0 parts by mass MEK-ST-L (Colloidal silica dispersion, silica MEK-
ST particles with different particle size, average particle size 45 nm, solid content concentration 30
(Mass%: manufactured by Nissan Chemical Co., Ltd.) 1.3 parts by mass The sol solution 0.6 parts by mass Methyl ethyl ketone 5.0 parts by mass Cyclohexanone 0.6 parts by mass ─────────────── ────────────────────────

  After adding the above composition and stirring, it was filtered through a polypropylene filter having a pore size of 1 μm to prepare a coating solution A for low refractive index layer. The refractive index of the layer formed with this coating solution was 1.45.

(Preparation of dispersion A)
Hollow silica fine particle sol (Isopropyl alcohol silica sol, average particle diameter 60 nm, shell thickness 10 nm, silica concentration 20% by mass, silica particle refractive index 1.31, prepared by changing the size according to Preparation Example 4 of JP-A-2002-79616 ) After adding 30 parts by mass of acryloyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) and 1.5 parts by mass of diisopropoxyaluminum ethyl acetate to 500 parts by mass, 9 parts by mass of ion-exchanged water was added. added. After making it react at 60 degreeC for 8 hours, it cooled to room temperature and added 1.8 mass parts of acetylacetone. While adding cyclohexanone to 500 parts by mass of this dispersion so that the silica content was almost constant, solvent substitution was performed by distillation under reduced pressure at a pressure of 20 kPa. There was no generation of foreign matter in the dispersion, and the viscosity when the solid content concentration was adjusted to 20% by mass with cyclohexanone was 5 mPa · s at 25 ° C. When the residual amount of isopropyl alcohol in the obtained dispersion A was analyzed by gas chromatography, it was 1.5%.

───────────────────────────────────────── Coating solution B for low refractive index layer
────────────────────────────────────────
JTA-113 783.3 parts by weight Dispersion A 195 parts by weight (silica + surface treatment agent solid content of 39.0 parts by weight)
MEK-ST-L 30.0 parts by mass The sol solution 17.2 parts by mass ──────────────────────────────── ────────

  The above composition is added, and the coating liquid B for low refractive index is prepared by diluting with cyclohexane and methyl ethyl ketone so that the solid content concentration of the entire coating liquid becomes 6% by mass and the ratio of cyclohexane and methyl ethyl ketone is 10:90. did. The refractive index of the layer formed with this coating solution was 1.39.

────────────────────────
Coating liquid C for low refractive index layer
────────────────────────
JTA-113 56.5 parts by mass MEK-ST-L 5.6 parts by mass The sol solution 1.9 parts by mass PM980 (manufactured by Wako Pure Chemical Industries) 1.7 parts by mass Methyl ethyl ketone 31.5 parts by mass Cyclohexane 2.8 parts by mass ────────────────────────
The refractive index of the layer formed with this coating solution was 1.45.

(Preparation of dispersion B)
Surface modification (surface modification rate 30 wt% vs. hollow silica) of KBM5103 (Shin-Etsu Chemical Silane Coupling Agent) on hollow silica fine particles (CS60, manufactured by Catalytic Chemical Industry, average particle diameter 60 nm, shell thickness 10 nm), solid content concentration 18 A 2 wt% isopropyl alcohol dispersion was obtained.

────────────────────────────────
Coating liquid D for low refractive index layer
────────────────────────────────
1.0 part by mass of the sol P3 7.6 parts by mass described in JP-A No. 2004-45462 Dispersion B 7.8 parts by mass MP-triazine (manufactured by Sanwa Chemical Co., Ltd.) 0.1 part by mass RMS-033 (gelest 2.75 parts by weight Methyl ethyl ketone 73.5 parts by weight Cyclohexane 7.5 parts by weight ─────────────────────────────── ─
The refractive index of the layer formed with this coating solution was 1.38.

According to JIS-K7136, the haze of each film in which the light diffusion layer was formed was measured using a measuring instrument (manufactured by Murakami Color Research Laboratory, HR-100).
In addition, using an automatic goniophotometer GP-5 (manufactured by Murakami Color Research Laboratory Co., Ltd.), these light diffusing films are arranged perpendicular to the incident light, and scattered light is observed in all directions. Profiles were measured. The scattered light intensity of 30 ° with respect to the light intensity at the emission angle of 0 ° was determined.
The results are shown in Table 1.

[Example 1]
<Formation of optically anisotropic layer 2>
(Preparation of cellulose acetate solution)
The following composition was put into a mixing tank and stirred to dissolve each component to prepare a cellulose acetate solution.

────────────────────────────────────
Cellulose acetate solution composition ────────────────────────────────────
Cellulose acetate having an acetylation degree of 60.9% 100.0 parts by weight Triphenyl phosphate (plasticizer) 7.0 parts by weight Biphenyl diphenyl phosphate (plasticizer) 4.0 parts by weight The following dye 0.0006 parts by weight Methylene chloride ( 1st solvent) 402.0 parts by mass Methanol (second solvent) 60.0 parts by mass ────────────────────────────── ──────

(Preparation of matting agent dispersion)
The following composition was charged into a disperser and stirred to disperse each component to prepare a matting agent dispersion.

────────────────────────────────────
Matting agent dispersion ─────────────────────────────────────
Silica particles having an average particle diameter of 16 nm (AEROSIL R972,
: Nippon Aerosil Co., Ltd.) 2.0 parts by weight Methylene chloride (first solvent) 76.3 parts by weight Methanol (second solvent) 11.4 parts by weight Cellulose acetate solution 10.3 parts by weight ────── ──────────────────────────────

(Preparation of retardation increasing agent solution)
The following composition was put into a mixing tank and stirred while warming to 30 ° C. to dissolve each component to prepare a retardation increasing agent solution.

────────────────────────────────────
Retardation raising agent solution composition ─────────────────────────────────────
The following retardation increasing agent 20.0 parts by weight Methylene chloride (first solvent) 58.4 parts by weight Methanol (second solvent) 8.7 parts by weight Cellulose acetate solution 12.8 parts by weight ──────── ────────────────────────────

(Production of cellulose acetate film)
The cellulose acetate solution 94.75 parts by mass, the matting agent dispersion 1.30 parts by mass, and the retardation increasing agent solution 3.95 parts by mass were mixed after filtration and cast using a band casting machine. The mass ratio of the retardation increasing agent to cellulose acetate was 4.8%. A film having a residual solvent amount of 30% by mass was peeled from the band. At a temperature of 140 ° C., the film was transversely stretched at a stretch ratio of 28% using a tenter. After stretching, the stretch ratio was relaxed to 25% and held at 140 ° C. for 20 seconds. At this time, the residual solvent amount at the maximum widening point was 14% by mass. Thereafter, the clip was removed and dried at 130 ° C. for 45 minutes to produce a cellulose acetate film. The produced cellulose acetate film had a residual solvent amount of 0.2% by mass and a film thickness of 88 μm.

(Measurement of optical properties of optically anisotropic layer 2)
About the produced cellulose acetate film, light of wavelength 632.8nm was injected into the film normal direction using the ellipsometer (M-150, JASCO Corporation make), and Re retardation value was measured. Re (0 °) = 38 nm. Retardation values Re (40 °) and Re (−40 °) were measured with the slow axis in the plane being tilted at 40 ° and −40 °. Using the film thickness and the refractive index nx in the slow axis direction as parameters, the refractive index ny in the fast axis direction is fitted to these measured values Re (0 °), Re (40 °), and Re (−40 °). The refractive index nz in the thickness direction was obtained by calculation, and the Rth retardation value was determined. Rth = 175 nm. Furthermore, the Re retardation value was measured with light having a wavelength of 400 nm and 550 nm. Re (400 nm) / Re (550 nm) = 1.06. Therefore, the produced cellulose acetate film was used as the optically anisotropic layer 2 of the present invention below. The results are also shown in Table 2.

(Saponification treatment of cellulose acetate film)
One side of the prepared cellulose acetate film was coated with 25 N / m ^{2 of} 1.5 N potassium hydroxide in isopropyl alcohol, left at 25 ° C. for 5 seconds, washed with running water for 10 seconds, and air at 25 ° C. The surface of the film was dried by spraying. In this way, only one surface of the cellulose acetate film was saponified.

(Formation of alignment film)
On one surface of the saponified cellulose acetate film (transparent support), 24 ml / m ² of a coating solution having the following composition was applied with a # 14 wire bar coater. Drying was performed with warm air of 60 ° C. for 60 seconds, and further with warm air of 90 ° C. for 150 seconds. Next, the formed film was rubbed in the direction of 45 ° with the stretching direction of the cellulose acetate film (almost coincident with the slow axis).

────────────────────────────────────
Alignment film coating solution composition ────────────────────────────────────
The following modified polyvinyl alcohol 20 parts by weight Water 360 parts by weight Methanol 120 parts by weight Glutaraldehyde (crosslinking agent) 1.0 part by weight ───────────────────── ─────────────

<Formation of optically anisotropic layer 1>
A coating solution containing a discotic compound having the following composition was continuously applied to the prepared alignment film with a # 3.2 wire bar. For drying the solvent of the coating solution and orientation ripening of the discotic compound, heating was performed with warm air at 100 ° C. for 30 seconds, and further with warm air at 130 ° C. for 60 seconds. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation and the optically anisotropic layer 1 was formed to produce an optical compensation sheet 1.

────────────────────────────────────
Coating composition for optically anisotropic layer 1 ────────────────────────────────────
The following discotic compound (1) 41.01 parts by mass Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 parts by mass Cellulose acetate butyrate (CAB551-0.2, 0.34 parts by mass Cellulose acetate butyrate (CAB531-1, manufactured by Eastman Chemical Co.) 0.11 parts by mass The following fluoroaliphatic group-containing polymer 1 0.03 parts by mass The following fluoroaliphatic group-containing Polymer 2 20.23 parts by mass Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.35 parts by mass Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.45 parts by mass Methyl ethyl ketone 107 parts by mass ──────────────────────────── ────────

(Measurement of optical properties of optically anisotropic layer 1)
The optically anisotropic layer 1 was formed in the same manner as described above except that the transparent support was changed to a glass plate. Using an ellipsometer (M-150, manufactured by JASCO Corporation), light having a wavelength of 632.8 nm was incident in the normal direction of the film, and the Re retardation value of the optically anisotropic layer 1 was measured. Re (0 °) = 30 nm. Retardation Re (40 °) and Re (−40 °) were measured with the in-plane slow axis as the tilt axis at 40 ° and −40 °. Re (40 °) = 52.8 nm and Re (−40 °) = 13.8 nm.
Therefore, Re (40 °) / Re (0 °) = 1.76 and Re (−40 °) / Re (0 °) = 0.46. The results are also shown in Table 3.

(Preparation of backlight side elliptical polarizing plate)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film.
Next, the transparent support (cellulose acetate film) side of the produced optical compensation sheet 1 was saponified and attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. The slow axis of the transparent support and the transmission axis of the polarizing film were arranged in parallel.
A commercially available cellulose triacetate film (Fujitac TD80U, manufactured by Fuji Photo Film Co., Ltd.) was saponified in the same manner as the transparent support, and the other side of the polarizing film (with an optical compensation sheet attached) using a polyvinyl alcohol adhesive Pasted on the side that did not exist).
In this way, a backlight side elliptical polarizing plate was produced.

(Preparation of viewing side elliptical polarizing plate)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film.
Next, the transparent support side of the produced optical compensation sheet 1 was saponified and attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. The slow axis of the transparent support and the transmission axis of the polarizing film were arranged in parallel.
A coating liquid A for low refractive index layer is applied on the light diffusion layer C of the film on which the light diffusion layer C with the low refractive index layer A (light diffusion layer C (haze: 47.7%) already formed) is formed. The cellulose acetate film side of the 100 nm-thick low refractive index layer A) was saponified in the same manner as the transparent support, and the other side of the polarizing film (optical compensation sheet) using a polyvinyl alcohol-based adhesive Was pasted on the side that was not pasted).
In this way, a viewing-side elliptical polarizing plate was produced.

(Preparation of bend alignment liquid crystal cell)
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The rubbing direction was a 45 ° direction in the screen. The two obtained glass substrates were faced to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 5 μm. A bend-aligned liquid crystal cell was prepared by injecting a liquid crystal compound (ZLI1132, manufactured by Merck & Co., Inc.) having a Δn of 0.1396 into the cell gap.

(Production of liquid crystal display device)
Two pieces of the produced backlight side and viewing side elliptical polarizing plates were attached so as to sandwich the produced bend alignment cell. One polarizing plate transmission axis was arranged in the 90 ° direction in the screen, and the other polarizing plate transmission axis was arranged in the 0 ° direction in the screen.
The optically anisotropic layer of the elliptically polarizing plate was arranged so as to face the cell substrate, and the rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer facing it were antiparallel.
The produced liquid crystal display device is placed on a backlight, a white display voltage of 2 V is applied to the liquid crystal cell, and a white luminance field in the rubbing direction of the liquid crystal cell is measured using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM). The angle (a polar angle (inclination angle from the normal) range of 50% with respect to the front white brightness) was measured. The results are shown in Table 4.

Hereinafter, Examples 2, 3, and 4 shall be read as Reference Examples 2, 3, and 4, respectively.
[Example 2]
The cellulose acetate film produced in Example 1 was immersed in a 1.5 N aqueous sodium hydroxide solution at 55 ° C. for 2 minutes. It wash | cleaned in the room temperature water-washing tub, and neutralized using 0.1 N sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. In this way, the surface of the cellulose acetate film was saponified.

(Formation of alignment film and optically anisotropic layer 1)
An alignment film was formed on the surface of the cellulose acetate film on the saponified side in the same manner as in Example 1, and a rubbing treatment was performed.
A coating solution containing a discotic compound having the following composition was continuously applied to the prepared alignment film with a # 1.6 wire bar. For drying the solvent of the coating solution and orientation ripening of the discotic compound, heating was performed with warm air at 100 ° C. for 30 seconds, and further with warm air at 130 ° C. for 60 seconds. Subsequently, the alignment of the liquid crystal compound was fixed by UV irradiation to form the optically anisotropic layer 1. Subsequently, the surface of the cellulose acetate film opposite to the surface on which the optically anisotropic layer 1 was formed was continuously saponified to produce an optical compensation sheet 2.

────────────────────────────────────
Composition of coating solution for optically anisotropic layer 1 ―――――――――――――――――――――――――――――――――――
91 parts by weight of the above discotic compound (1) Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9 parts by weight Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 3 parts by weight Part Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 1 part by mass The following pyridinium salt 0.5 part by mass The following fluoropolymer 0.4 part by mass Methanol 60 parts by mass Methyl ethyl ketone 330 parts by mass ――――――――――――――――――――――――――――― ───

(Measurement of optical properties of optically anisotropic layer 1)
The optical characteristics of the optically anisotropic layer 1 were measured in the same manner as in Example 1. The results are shown in Table 3.

(Preparation of backlight side elliptical polarizing plate)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film.
The optical compensation sheet 2 was saponified in the same manner as in Example 1, using a polyvinyl alcohol-based adhesive, so that the transparent support (cellulose acetate film) surface was on the polarizing film side, and on one side of the polarizing film. Pasted. The slow axis of the transparent support and the transmission axis of the polarizing film were arranged in parallel.
A commercially available cellulose triacetate film (Fujitac TD80U, manufactured by Fuji Photo Film Co., Ltd.) was saponified in the same manner as in Example 1, and a polyvinyl alcohol adhesive was used as the outer transparent protective film on the opposite side of the polarizing film. Pasted on.
In this way, a backlight side elliptical polarizing plate was produced.

(Preparation of viewing side elliptical polarizing plate)
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film.
Next, the transparent support side of the produced optical compensation sheet 2 was attached to one side of the polarizing film using a polyvinyl alcohol-based adhesive. The slow axis of the transparent support and the transmission axis of the polarizing film were arranged in parallel.
The cellulose acetate film side of the light diffusing layer C with the low refractive index layer A that has already been prepared is saponified in the same manner as the transparent support, and the opposite side of the polarizing film (optical compensation sheet) using a polyvinyl alcohol-based adhesive. Was pasted on the side that was not pasted).
In this way, a viewing-side elliptical polarizing plate was produced.

(Preparation of bend alignment liquid crystal cell)
A polyimide film was provided as an alignment film on a glass substrate with an ITO electrode, and the alignment film was rubbed. The rubbing direction was a 135 ° direction in the screen. The obtained two glass substrates were faced to each other so that the rubbing directions were parallel to each other, and the cell gap was set to 4 μm. A bend-aligned liquid crystal cell was prepared by injecting a liquid crystal compound (ZLI1132, manufactured by Merck & Co., Inc.) having a Δn of 0.1396 into the cell gap.

(Production of liquid crystal display device)
Two produced elliptical polarizing plates were attached so as to sandwich the produced bend alignment cell. Two produced elliptical polarizing plates were attached so as to sandwich the produced bend alignment cell. One polarizing plate transmission axis was arranged in the 90 ° direction in the screen, and the other polarizing plate transmission axis was arranged in the 0 ° direction in the screen.
The optically anisotropic layer of the elliptically polarizing plate was arranged so as to face the cell substrate, and the rubbing direction of the liquid crystal cell and the rubbing direction of the optically anisotropic layer facing it were antiparallel.
The produced liquid crystal display device is placed on a backlight, a white display voltage of 2 V is applied to the liquid crystal cell, and a white luminance field in the rubbing direction of the liquid crystal cell is measured using a measuring instrument (EZ-Contrast 160D, manufactured by ELDIM). The angle (a polar angle (inclination angle from the normal) range of 50% with respect to the front white brightness) was measured. The results are shown in Table 4.

[Example 3]
The cellulose acetate film produced in Example 1 was immersed in a 1.5 N aqueous sodium hydroxide solution at 55 ° C. for 2 minutes. It wash | cleaned in the room temperature water-washing tub, and neutralized using 0.1 N sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. In this way, the surface of the cellulose acetate film was saponified.

(Formation of alignment film and optically anisotropic layer)
An alignment film was formed on the surface of the cellulose acetate film on the saponified side in the same manner as in Example 1, and a rubbing treatment was performed.
90 parts by mass of the above-described discotic compound (1), 6 parts by mass of ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.), bifunctional acrylate on the alignment film subjected to rubbing treatment Monomer (NK ester A400, Shin-Nakamura Chemical Co., Ltd.) 4 parts by mass, fluorine-based oligomer (FSN100, manufactured by DuPont), 0.3 part by mass, the following photopolymerization initiator 3 parts by mass, 179.7 parts by mass A coating solution dissolved in a portion of methyl ethyl ketone was applied with 5.2 ml / m ² with a # 3 wire bar coater. This was affixed to a metal frame and heated in a thermostatic bath at 130 ° C. for 2 minutes to orient the discotic compound. Next, using a 120 W / cm high-pressure mercury lamp at 90 ° C., UV irradiation was performed for 1 minute to polymerize the discotic compound. Then, it stood to cool to room temperature. Thus, the optically anisotropic layer 1 was formed and the optical compensation sheet 3 was produced.

[Example 4]
The cellulose acetate film produced in Example 1 was immersed in a 1.5 N aqueous sodium hydroxide solution at 55 ° C. for 2 minutes. It wash | cleaned in the room temperature water-washing tub, and neutralized using 0.1 N sulfuric acid at 30 degreeC. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. In this way, the surface of the cellulose acetate film was saponified.

(Formation of alignment film and optically anisotropic layer)
An alignment film was formed on the surface of the cellulose acetate film on the saponified side in the same manner as in Example 1, and a rubbing treatment was performed.
To 102 kg of methyl ethyl ketone, the above discotic compound (1) 41.01 kg, ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 4.06 kg, cellulose acetate butyrate (CAB531-1) 0.18 Kg, manufactured by Eastman Chemical Co., Ltd., cellulose acetate butyrate (CAB551-0.2, manufactured by Eastman Chemical Co.) 0.07 Kg, photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy Co.) 1.35 Kg, increased Sensitizer (Kayacure DETX, Nippon Kayaku Co., Ltd.) 0.45 kg was dissolved. To the solution, 0.1 kg of a fluoroaliphatic group-containing copolymer (Megafac F780 manufactured by Dainippon Ink, Inc.) was added to prepare a coating solution. The coating solution was continuously applied to the alignment film surface of the transparent film being conveyed at 20 m / min by rotating the wire bar of # 3.2 by 391 rotations in the same direction as the film conveying direction.
The temperature was continuously heated from room temperature to 100 ° C., the solvent was dried, and then the film surface wind speed of the disc-like optically anisotropic layer was 2.5 m / sec in a drying zone at 130 ° C. The disc-shaped liquid crystalline compound was aligned by heating for 2 seconds. Next, the film is transported to a drying zone at 80 ° C., and an ultraviolet ray with an illuminance of 600 mW is applied by an ultraviolet irradiation device (ultraviolet lamp: output 160 W / cm, emission length 1.6 m) with the surface temperature of the film being about 100 ° C. Irradiation was performed for 4 seconds to advance the crosslinking reaction, and the discotic liquid crystalline compound was fixed to the orientation. Then, it was allowed to cool to room temperature and wound into a cylindrical shape to form a roll. Thus, the optical anisotropic layer 1 was formed and the optical compensation sheet 4 was produced.

[Comparative Example 1]
Only the cellulose acetate film prepared in Example 1 was used as the optical compensation sheet 5.

(Measurement of optical properties of optically anisotropic layer 1)
The optical characteristics of the optically anisotropic layer 1 of Example 3 and Example 4 were measured in the same manner as in Example 1. The results are shown in Table 3.
Further, for the optical compensation sheets of Example 3, Example 4, and Comparative Example 1, as in Example 1, backlight-side and viewing-side elliptical polarizing plates and liquid crystal display devices were prepared, and a white luminance viewing angle was obtained. Was measured. The results are shown in Table 4.

  Hereinafter, for Examples 1 to 4 and Comparative Example 1, the optical properties of the optical anisotropic layer 2 (Table 2), the optical properties of the optical anisotropic layer 1 (Table 3), and the white luminance viewing angle (Table 4). ) Is shown in a table.

As is clear from Tables 2 to 4, in the liquid crystal display device of the present invention in which the retardation values of the two types of optically anisotropic layers 1 and 2 of the optical compensation sheet are in an appropriate range, the liquid crystal cell in the rubbing direction White brightness could be increased.
The same effect was obtained when the light diffusion layer C of Example 1 was replaced with the light diffusion layers B, C, E, and F. However, when the light diffusion layer D was used, the liquid crystal cell was rubbed. The brightness difference between the vertical direction and the rubbing direction was large, resulting in display quality with poor symmetry.

Further, the same effect was confirmed even when the low refractive index layer A of Example 1 was changed to B to D, or even when there was no low refractive index layer.
Further, by using the low refractive index layers A and C and the low refractive index layers B and D containing hollow silica fine particles, the reflectance on the viewing side is reduced and the visibility (contrast) is improved.

It is a conceptual diagram which shows the relationship of the optical compensation in the liquid crystal display device using the liquid crystal cell of a bend alignment mode. 4 is a chart showing preferred regions of a wavelength dispersion value (α1) of the optically anisotropic layer 1 and a wavelength dispersion value (α2) of the optically anisotropic layer 2.

Explanation of symbols

10 Bend alignment liquid crystal cell 31A, B Optically anisotropic layer 1
32A, B Optically anisotropic layer 2
RD1, RD4 Rubbing directions RD2, RD3 for aligning the discotic compound of the optically anisotropic layer

Claims (8)

A pair of polarizing film, a liquid crystal cell thereof bend alignment mode that will be disposed between, and having an optical compensation sheet disposed between at least one of the polarizing film and the liquid crystal cell, the optical compensation sheet is the following formula A liquid crystal display device having an optically anisotropic layer 1 satisfying (I) and (II) and an optically anisotropic layer 2 satisfying the following formulas (III) and (IV):
A liquid crystal display device comprising a light diffusion layer having a haze value of 45% or more and 80% or less on a surface on a viewing side.
(I) 1.0 <Re (40 °) / Re (0 °) <2. 0
(II) 0.1 <Re (−40 °) / Re (0 °) <1.0
(III) 10 nm <Re (0 °) <70 nm
(IV) 70 nm <Rth <400 nm
[In the above formula, Re and Rth respectively represent in-plane retardation and retardation in the thickness direction of the optically anisotropic layer measured with light having a wavelength of 632.8 nm. Re (0 °) is the Re retardation value measured by making light incident in the normal direction of the film, and Re (40 °) is the slow axis of the optically anisotropic layer and the tilt angle is 40. Re Retardation value measured with light incident as °, and Re (−40 °) is measured with light incident with the slow axis of the optically anisotropic layer as the tilt axis and tilt angle as −40 °. The positive and negative tilt angles are determined so that Re (40 °)> Re (−40 °). ]   The liquid crystal display device according to claim 1, wherein the optically anisotropic layer 1 contains a surfactant.   The liquid crystal display device according to claim 2, wherein the surfactant is the following fluoroaliphatic group-containing polymer 1.

  The liquid crystal display device according to claim 2, wherein the surfactant is the following fluoroaliphatic group-containing polymer 2.

The liquid crystal display device according to claim 1, wherein the optically anisotropic layer 1 is made of a discotic compound. The liquid crystal display device according to claim 1, wherein the optically anisotropic layer 2 is made of a cellulose acylate film. 2. The light diffusing layer has a scattered light intensity of 30 ° in a range of 0.05 to 0.3% with respect to a light intensity at an output angle of 0 ° of a scattered light profile of a goniophotometer. 7. A liquid crystal display device according to any one of items 6 to 6 . The liquid crystal display device according to any one of claims 1乃optimum 7 refractive index on the light diffusion layer, characterized in that the low refractive index layer is provided in the 1.20-1.50.

Images