JP4202877B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device, and more particularly to a vertical alignment nematic liquid crystal display device having excellent viewing angle characteristics.

  The liquid crystal display device usually includes a liquid crystal cell and a polarizing plate. The polarizing plate has a protective film and a polarizing film. For example, the polarizing film made of a polyvinyl alcohol film is dyed with iodine, stretched, and both surfaces thereof are laminated with a protective film. In the transmissive liquid crystal display device, the polarizing plate is attached to both sides of the liquid crystal cell, and one or more optical compensation sheets may be disposed. In a reflective liquid crystal display device, a reflector, a liquid crystal cell, one or more optical compensation sheets, and a polarizing plate are arranged in this order. The liquid crystal cell includes a liquid crystal molecule, two substrates for encapsulating the liquid crystal molecule, and an electrode layer for applying a voltage to the liquid crystal molecule. The liquid crystal cell performs ON / OFF display depending on the alignment state of liquid crystal molecules, and can be applied to both transmission type and reflection type, such as TN (Twisted Nematic), IPS (In-Plane Switching), OCB (Optically). Display modes such as Compensatory Bend), VA (Vertically Aligned), and ECB (Electrically Controlled Birefringence) have been proposed.

  Among such liquid crystal display devices (LCDs), for applications that require high display quality, nematic liquid crystal molecules having positive dielectric anisotropy and 90-degree twisted nematic liquid crystal display devices driven by thin film transistors ( Hereinafter, the TN mode) is mainly used. However, although the TN mode has excellent display characteristics when viewed from the front, the contrast is reduced when viewed from an oblique direction, or gradation inversion that reverses the brightness in gradation display occurs. There is a viewing angle characteristic that the display characteristic is deteriorated, and this improvement is strongly demanded.

  In recent years, as an LCD method for improving the viewing angle characteristics, nematic liquid crystal molecules having negative dielectric anisotropy are used, and the major axis of the liquid crystal molecules is set in a direction substantially perpendicular to the substrate in a non-driven state without applying voltage. A vertical alignment nematic liquid crystal display device (hereinafter referred to as VA mode) in which alignment is performed and driven by a thin film transistor has been proposed (see Patent Document 1). This VA mode not only has excellent display characteristics when viewed from the front, but also exhibits a wide viewing angle characteristic by applying a viewing angle compensation phase difference film. In the VA mode, a wide viewing angle characteristic can be obtained by using two negative uniaxial retardation films having an optical axis in a direction perpendicular to the film surface, above and below the liquid crystal cell. It is also known that a wider viewing angle characteristic can be realized by using a uniaxially oriented retardation film having a positive refractive index anisotropy with a retardation value of 50 nm (see Non-Patent Document 1). .

However, the use of three retardation films (see Non-Patent Document 1) not only causes an increase in production cost, but also causes a decrease in yield due to the bonding of a large number of films, and further uses a plurality of films. For this reason, there is a problem that the thickness is increased, which is disadvantageous for thinning the display device. Moreover, since an adhesive layer is used for lamination | stacking of a stretched film, an adhesive layer shrink | contracts by a temperature / humidity change, and defects, such as peeling and a curvature between films, may generate | occur | produce. As a method for improving these, a method for reducing the number of retardation films and a method using a cholesteric liquid crystal layer are disclosed (see Patent Documents 2 and 3). However, even in these methods, it is necessary to bond a plurality of films, which is insufficient in terms of thinning and reduction of production costs. Furthermore, there was a problem that light leakage from the oblique direction of the polarizing plate during black display was recognized, and the viewing angle was not sufficiently expanded (to the extent expected theoretically).
Japanese Patent Laid-Open No. 2-176625 JP-A-11-95208 JP 2003-15134 A SID 97 DIGEST Pages 845-848

  An object of the present invention is to provide a liquid crystal display device, particularly a VA mode liquid crystal display device, in which a liquid crystal cell is accurately optically compensated, the number of sheets to be bonded can be reduced, and the thickness can be reduced. .

The object of the present invention has been achieved by the following liquid crystal display devices [1] to [5].
[1] having two polarizing films whose absorption axes are orthogonal to each other and a liquid crystal layer composed of a pair of substrates and liquid crystalline molecules sandwiched between the two polarizing films. A liquid crystal cell in which the liquid crystalline molecules are aligned in a direction substantially perpendicular to the substrate in a non-driving state in which no external electric field is applied; and a rod-like liquid crystal property having an optically positive refractive index anisotropy It is formed from a composition containing a compound, and the Re defined below for visible light is 40 to 150 nm, and the value obtained by dividing Re at a wavelength of 478 nm by Re at a wavelength of 748 nm is 1.00 or more and 1 0.11 or less of the first optically anisotropic layer, optically negative refractive index anisotropy, Re defined below for visible light is 10 nm or less, and Rth is Second optically anisotropic layer having a thickness of 60 to 250 nm A liquid crystal display device.
Re = (nx−ny) × d (1)
Rth = {(nx + ny) / 2−nz} × d (2)
(Where nx is the refractive index in the slow axis direction in the plane of the layer, ny is the refractive index in the plane perpendicular to nx, nz is the refractive index in the thickness direction of the layer, and d is the thickness of the layer) .)

[2] having two polarizing films whose absorption axes are orthogonal to each other and a liquid crystal layer composed of a pair of substrates and liquid crystalline molecules sandwiched between the two polarizing films. A liquid crystal cell in which the liquid crystalline molecules are aligned in a direction substantially perpendicular to the substrate in an undriven state in which no external electric field is applied, and has an optically positive refractive index anisotropy, At least a first optically anisotropic layer formed from a composition containing a compound represented by (I) or the general formula (II) and having a Re defined below with respect to visible light of 40 to 150 nm. And at least one second optically anisotropic layer having an optically negative refractive index anisotropy, Re defined above for visible light of 10 nm or less, and Rth of 60 to 250 nm. A liquid crystal display device.

（式中、Ａ¹およびＡ²はそれぞれ置換基を表し、ｍおよびｎはそれぞれ０〜４の整数であり、Ｂ¹およびＢ²はそれぞれ置換基であるが、Ｂ¹およびＢ²の少なくとも一方は重合性基を含む。Ｃ¹は一般式（Ｉ）中のベンゼン環と共役せず、且つ芳香族環同士が縮合した縮合芳香環を含まない２価の基である。）

(In the formula, A ¹ and A ² each represent a substituent, m and n are each an integer of 0 to 4, B ¹ and B ² are each a substituent, and at least one of B ¹ and B ² Includes a polymerizable group, and C ¹ is a divalent group that is not conjugated with the benzene ring in the general formula (I) and does not include a condensed aromatic ring in which aromatic rings are condensed.

（式中、Ａ¹は置換基を表し、ｍは０〜４の整数である。Ｂ¹およびＢ²はそれぞれ置換基であり、Ｂ¹およびＢ²の少なくとも一方は重合性基を含む。Ｄ¹は飽和６員環を含むが、ベンゼン環および芳香族環同士が縮合した縮合芳香族環を含まず、且つ式中のベンゼン環と共役していない２価の基である。）

(In the formula, A ¹ represents a substituent, and m is an integer of 0 to 4. B ¹ and B ² are each a substituent, and at least one of B ¹ and B ² contains a polymerizable group. D ¹ is a divalent group that contains a saturated 6-membered ring but does not contain a condensed benzene ring and a condensed aromatic ring obtained by condensing aromatic rings, and is not conjugated to the benzene ring in the formula.

[3] The liquid crystal according to [1], wherein the first optically anisotropic layer is a layer formed from a composition containing a compound represented by the general formula (I) or the general formula (II). Display device.
[4] The first optically anisotropic layer is a layer formed from a composition containing a compound represented by the following general formula (III) or the following general formula (IV) [1] or [2 ] Liquid crystal display device as described in.

（式中Ａ¹およびＡ²はそれぞれ置換基を表し、ｍおよびｎはそれぞれ０〜４の整数であり、Ｂ¹およびＢ²はそれぞれ置換基であり、Ｂ¹およびＢ²の少なくとも一方は重合性基を含む。）

(In the formula, A ¹ and A ² each represent a substituent, m and n are each an integer of 0 to 4, B ¹ and B ² are each a substituent, and at least one of B ¹ and B ² is polymerized. Contains a sex group.)

（式中Ａ¹およびＡ²はそれぞれ置換基を表し、ｍおよびｎはそれぞれ０〜４の整数であり、Ｂ¹およびＢ²はそれぞれ置換基であり、Ｂ¹およびＢ²の少なくとも一方は重合性基を含む。）

(In the formula, A ¹ and A ² each represent a substituent, m and n are each an integer of 0 to 4, B ¹ and B ² are each a substituent, and at least one of B ¹ and B ² is polymerized. Contains a sex group.)

[5] The liquid crystal according to any one of [1] to [4], wherein the second optically anisotropic layer is a layer formed from a composition containing a discotic liquid crystalline compound having a polymerizable group. Display device.

  In the present specification, “substantially” with respect to an angle means that the angle is within a range of an exact angle of less than ± 5 °. The error from the exact angle is preferably less than 4 °, more preferably less than 3 °. Further, the “slow axis” means a direction in which the refractive index is maximized. Further, the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. In this specification, “visible light” means 400 nm to 700 nm, and the measurement wavelength of the refractive index is a value at λ = 550 nm in the visible light region unless otherwise specified. In this specification, “polarizing film” and “polarizing plate” are distinguished from each other, and “polarizing plate” is a laminate having a transparent protective film for protecting the polarizing film on at least one side of the “polarizing film”. Means. In the present specification, the description “(numerical value 1) to (numerical value 2)” means “(numerical value 1) or more and (numerical value 2) or less”.

  In the present invention, it is possible to optically accurately compensate a liquid crystal cell with the same configuration as a conventional liquid crystal display device by using an optically anisotropic layer exhibiting predetermined optical characteristics. In the liquid crystal display device of the present invention, not only the display quality but also the viewing angle is remarkably improved. In addition, in a conventional liquid crystal display device, in order to incorporate an optical compensation sheet, a step of laminating while strictly adjusting the angles of a plurality of retardation films and polarizing plates is necessary. There is no need, and there is a great merit in terms of cost. That is, according to the present invention, it is possible to provide a liquid crystal display device, in particular, a VA mode liquid crystal display device in which the liquid crystal cell is accurately optically compensated and the number of layers to be bonded is small and can be thinned.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be specifically described. First, an embodiment of the liquid crystal display device of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an example of the configuration of a liquid crystal display device of the present invention, and FIG. 2 is a configuration of a polarizing plate usable in the present invention. In FIG. 1, an example in which active driving is performed using a nematic liquid crystal having negative dielectric anisotropy as a field effect liquid crystal will be described.

[Liquid Crystal Display]
In FIG. 1, the liquid crystal display device includes a liquid crystal cell (5 to 8) and a pair of polarizing plates 1 and 12 disposed on both sides of the liquid crystal cell. A first optically anisotropic layer 3 is provided between the polarizing plate 1 and the liquid crystal cells 5 to 8, and a second optically anisotropic layer 10 is provided between the polarizing plate 14 and the liquid crystal cells 5 to 8. Is arranged. The liquid crystal cell includes an upper electrode substrate 5, a lower electrode substrate 8, and liquid crystal molecules 7 sandwiched between them. The liquid crystal molecules 7 are aligned in a direction substantially perpendicular to the substrate in a non-driven state in which no external electric field is applied, by rubbing treatment directions 6 and 9 applied to the opposing surfaces of the electrode substrates 5 and 8. Is controlled to do. The upper polarizing plate 1 and the lower polarizing plate 14 are laminated so that the absorption axis 2 and the absorption axis 13 are substantially orthogonal.

  As shown in FIG. 2, the polarizing plates 1 and 12 include a polarizing film 103 sandwiched between protective films 101 and 105. The polarizing plates 1 and 12 can be produced by, for example, dyeing a polarizing film made of a polyvinyl alcohol film with iodine and performing stretching to obtain the polarizing film 103 and laminating protective films 101 and 105 on both sides thereof. it can. In the case of lamination, it is preferable in terms of productivity to bond a total of three films of a pair of protective film and polarizing film with a roll, a TO, and a roll. In addition, in the lamination of rolls, TOs and rolls, as shown in FIG. 2, the slow axes 102 and 106 of the protective films 101 and 105 and the absorption axis 104 of the polarizing film 103 can be easily laminated. It is preferable because the polarizing plate has a high mechanical stability in which the dimensional change and curling of the polarizing plate hardly occur. The same effect can be obtained if at least two axes of the three films, for example, the slow axis of one protective film and the absorption axis of the polarizing film, or the slow axes of the two protective films are substantially parallel. can get.

Referring again to FIG. 1, the first optically anisotropic layer 3 is formed of a composition having an optically positive refractive index anisotropy and containing a rod-like liquid crystalline compound, and has retardation (with respect to visible light). Re) is 40 to 150 nm. On the other hand, the second optical anisotropic layers 10 and 12 have an optically negative refractive index anisotropy, Re is 10 nm or less and Rth is 60 to 250 nm with respect to visible light. There is no restriction | limiting in particular about the material which comprises the 2nd optically anisotropic layer 10, The layer which consists of a liquid crystalline compound, or a polymer film may be sufficient. These optically anisotropic layers 3 and 10 eliminate the image coloring of the liquid crystal cell and contribute to the expansion of the viewing angle.
In the liquid crystal display device of FIG. 1, an example in which two second optically anisotropic layers are used has been described. However, the second optically anisotropic layer may be a single layer, or three or more layers. There may be. The same applies to the first optical anisotropic layer.

  In FIG. 1, when the upper side is the observer side, in FIG. 1, the first optical anisotropic layer 3 is formed between the observer-side polarizing plate 1 and the observer-side liquid crystal cell substrate 5. 2 shows a configuration in which the optically anisotropic layer 10 is disposed between the back-side polarizing plate 14 and the back-side liquid crystal cell substrate 8, but the first optically anisotropic layer and the second optically anisotropic layer 10 are arranged. The configuration may be such that the isotropic layer is replaced, and both the first and second optical anisotropic layers are provided between the polarizing plate 1 on the viewer side and the substrate 5 for the viewer side liquid crystal cell. Or may be disposed between the back-side polarizing plate 14 and the back-side liquid crystal cell substrate 8. In such an embodiment, the second optical anisotropic layer may also serve as a support for the first optical anisotropic layer. Further, the first optically anisotropic layer 3 may be integrated with the polarizing plate 1 and can be incorporated in the liquid crystal display device in an integrated state with the polarizing plate 1. Since the first optically anisotropic layer is made of a rod-like liquid crystalline compound, it is usually formed on a support. For example, the support of the first optically anisotropic layer may function as a protective film on one side of the polarizing film, and the transparent protective film, the polarizing film, the transparent protective film (also used as the transparent support) and the first It is preferable to form an integrated polarizing plate laminated in the order of one optically anisotropic layer. When the integrated polarizing plate is incorporated in a liquid crystal display device, a transparent protective film, a polarizing film, a transparent protective film (also a transparent support), and the first optical anisotropy are formed from the outside of the device (the side far from the liquid crystal cell). It is preferable to incorporate them in the order of the active layers.

  The same applies to the second optically anisotropic layer 10 and can be incorporated in the liquid crystal display device as an integrated polarizing plate integrated with the polarizing plate 12, and the second optically anisotropic layer 10 is a liquid crystalline compound. In one embodiment, one protective film of the polarizing plate 12 may also serve as the transparent support of the second optically anisotropic layer 10. In such an embodiment, the integrated polarizing plate is laminated in the order of a transparent protective film, a polarizing film, a transparent protective film (also used as a transparent support) and a second optically anisotropic layer, The liquid crystal display device is preferably incorporated into the liquid crystal display device in the order of a transparent protective film, a polarizing film, a transparent protective film (also a transparent support), and a second optically anisotropic layer from the side far from the liquid crystal cell. Further, when the second optical anisotropic layer 10 is a polymer film, the second optical anisotropic layer 10 may be one protective film of the polarizing plate 12. In this embodiment, the integrated polarizing plate is laminated in the order of the transparent protective film, the polarizing film, and the second optically anisotropic layer (also serving as the transparent protective film), and the integrated polarizing plate is disposed outside (distant from the liquid crystal cell). The liquid crystal display device is preferably incorporated in the order of the transparent protective film, the polarizing film, and the second optically anisotropic layer (also known as the transparent protective film) from the side.

  The liquid crystal display device of the present invention is not limited to the above configuration, and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizing film. In the transmissive liquid crystal display device, a backlight using a cold or hot cathode fluorescent tube, a light emitting diode, or an electroluminescent element as a light source can be disposed on the back surface. On the other hand, in the aspect of the reflective liquid crystal display device, only one polarizing plate is required on the observation side, and a reflective film is provided on the back surface of the liquid crystal cell or the inner surface of the lower substrate of the liquid crystal cell. Of course, it is also possible to provide a front light using the light source on the liquid crystal cell observation side. Further, a transflective type in which a transmissive portion and a reflective portion are provided in one pixel of the display device is also possible.

  The type of the liquid crystal display device of the present invention is not particularly limited, and includes any of image direct view type, image projection type, and light modulation type liquid crystal display devices. The present invention is effective for an active matrix liquid crystal display device using three-terminal or two-terminal semiconductor elements such as TFT and MIM. Of course, it is also effective in a passive matrix liquid crystal display device represented by STN type called time-division driving.

[VA mode liquid crystal cell]
In the present invention, the liquid crystal cell is preferably in the VA mode. The VA mode liquid crystal cell is formed by sealing liquid crystal molecules having negative dielectric anisotropy between upper and lower substrates whose opposite surfaces are rubbed. For example, by using liquid crystal molecules having Δn = 0.0813 and Δε = −4.6, a director indicating the alignment direction of the liquid crystal molecules, that is, a liquid crystal cell having a so-called tilt angle of about 89 ° can be manufactured. At this time, the thickness d of the liquid crystal layer can be about 3.5 μm. The brightness at the time of white display changes according to the magnitude of the product Δnd of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn. In order to obtain the maximum brightness, the product Δnd of the thickness d of the liquid crystal layer and the refractive index anisotropy Δn is preferably in the range of 0.2 to 0.5 μm.

  A transparent electrode (not shown) is formed inside each alignment film (not shown) of the substrate 5 and the substrate 8, but the liquid crystal in the liquid crystal layer is in a non-driving state where no driving voltage is applied to the electrodes. The molecules 7 are aligned substantially perpendicular to the substrate surface, and as a result, the polarization state of the light passing through the liquid crystal panel hardly changes. As described above, since the absorption axis 2 of the upper polarizing plate 1 of the liquid crystal cell and the absorption axis 15 of the lower polarizing plate 14 are substantially orthogonal to each other, light does not pass through the polarizing plate, that is, in FIG. In the liquid crystal display device, an ideal black display is realized in a non-driven state. On the other hand, in the driving state, the liquid crystal molecules are inclined in a direction parallel to the substrate surface, and the light passing through the liquid crystal panel changes the polarization state by the inclined liquid crystal molecules and passes through the polarizing plate. In other words, the liquid crystal display device of FIG. 1 can obtain white display in the driving state.

Here, since an electric field is applied between the upper and lower substrates, an example using a liquid crystal material having a negative dielectric anisotropy in which liquid crystal molecules respond perpendicularly to the electric field direction is shown. In the case where an electrode is disposed on one substrate and an electric field is applied in a lateral direction parallel to the substrate surface, a liquid crystal material having a positive dielectric anisotropy can be used.
In a VA mode liquid crystal display device, the addition of a chiral material generally used in a TN mode liquid crystal display device is rarely used to degrade dynamic response characteristics, but to reduce alignment defects. May be added.

  The features of the VA mode are high-speed response and high contrast. However, there is a problem that the contrast is high in the front but decreases in the oblique direction. During black display, the liquid crystal molecules are aligned perpendicular to the substrate surface. When observed from the front, the liquid crystal molecules have almost no birefringence, so the transmittance is low and a high contrast can be obtained. However, when observed obliquely, birefringence occurs in the liquid crystalline molecules. Further, the crossing angle of the upper and lower polarizing plate absorption axes is 90 ° perpendicular to the front, but is larger than 90 ° when viewed from an oblique direction. Because of these two factors, leakage light occurs in the oblique direction, and the contrast is lowered. In the present invention, in order to solve this problem, at least one first and second optically anisotropic layers are arranged.

  In the VA mode, liquid crystal molecules are tilted during white display, but the birefringence of the liquid crystal molecules when viewed from an oblique direction is different between the tilt direction and the opposite direction, resulting in differences in luminance and color tone. . In order to solve this, the liquid crystal cell is preferably multi-domain. Multi-domain refers to a structure in which a plurality of regions having different alignment states are formed in one pixel. For example, in a multi-domain VA mode liquid crystal cell, a plurality of regions in which tilt angles of liquid crystal molecules are different from each other when an electric field is applied exist in one pixel. In a multi-domain VA mode liquid crystal cell, the tilt angle of liquid crystal molecules due to application of an electric field can be averaged for each pixel, whereby the viewing angle characteristics can be averaged. In order to divide the orientation within one pixel, the electrode is provided with slits or protrusions, and the electric field direction is changed or the electric field density is biased. In order to obtain a uniform viewing angle in all directions, the number of divisions may be increased, but a substantially uniform viewing angle can be obtained by dividing into four or eight or more. Further, a CPA (Continuous Pinwheel Alignment) system in which liquid crystal molecules are continuously aligned radially from the center has been proposed, for example, on page 201 of AM-LCD '01 (2001). In this case, since the orientation control direction is uniform over 360 degrees, it is possible to obtain a uniform viewing angle in all directions. The alignment control processing directions 6 and 9 due to the protrusions and the absorption axes 2 and 13 of the polarizing plate are retardations generated when the liquid crystal molecules 7 are inclined in the horizontal direction in the vertical plane including the alignment control processing direction when a voltage is applied. In order to change the polarization state, it is preferable to make an angle of 1 to 89 degrees. Furthermore, although it changes also with the above-mentioned division | segmentation number, if it is 4 divisions, 40-60 degrees is more preferable, and if it is 8 divisions, 20-70 degrees is more preferable. In the CPA method, since the orientation control treatment direction is uniform over 360 degrees, the absorption axis of the polarizing plate can be set to an arbitrary angle.

  Also, the liquid crystal molecules are difficult to respond at the alignment division region boundary. For this reason, in normally black display, since black display is maintained, a reduction in luminance becomes a problem. Adding a chiral agent to the liquid crystal material contributes to reducing the boundary region.

Hereinafter, the first and second optically anisotropic layers used in the liquid crystal display device of the present invention will be described in detail.
In the present invention, the first and second optically anisotropic layers eliminate image coloring of the liquid crystal display device and contribute to the expansion of the viewing angle. In addition, when the support of the optically anisotropic layer also serves as a protective film for the polarizing plate, or the optically anisotropic layer also serves as the protective film for the polarizing plate, the number of constituent members of the liquid crystal display device can be reduced. Therefore, in this aspect, it contributes also to thickness reduction of a liquid crystal display device.

  In the present invention, the first optically anisotropic layer is made of a rod-like liquid crystalline compound. The raw material of the second optically anisotropic layer is not particularly limited, but may be formed from a liquid crystalline compound. An optically anisotropic layer made of a liquid crystalline compound can realize optical properties that cannot be obtained with a conventional stretched birefringent polymer film. In particular, the combination of the first optical anisotropic layer made of a rod-like liquid crystal compound and the second optical anisotropic layer made of a disk-like compound can significantly improve the optical characteristics of the liquid crystal display device.

In the present invention, the in-plane retardation (Re) of the first optical anisotropic layer is 40 to 150 nm, the Re of the second optical anisotropic layer is 10 nm or less, and the Rth is 60 to 250 nm. Since the first and second optically anisotropic layers have an optical compensation function as a whole when combined, it is more preferable to adjust the combined overall retardation. As a whole, the first and second optically anisotropic layers are preferably combined so that Re is 30 to 200 nm and Rth is 60 to 500 nm. Here, Re and Rth are respectively defined by the following equations.
Re = (nx−ny) × d (1)
Rth = {(nx + ny) / 2−nz} × d (2)
In the formula, nx represents the refractive index in the slow axis direction in the plane of the layer, ny represents the refractive index in the plane perpendicular to nx, nz represents the refractive index in the thickness direction of the layer, and d represents the thickness of the layer.

[First optically anisotropic layer]
The 1st optically anisotropic layer used for this invention is formed from the composition containing a rod-shaped liquid crystalline compound, Re is 40-150 nm, Preferably it is 50-120 nm. The rod-like liquid crystalline compound preferably has a polymerizable group. In the case of a rod-like liquid crystal compound having a polymerizable group, it is preferably fixed in a substantially horizontal (homogeneous) orientation. Substantially horizontal means that the average angle (average inclination angle) between the major axis direction of the rod-like liquid crystalline compound and the surface of the optically anisotropic layer is in the range of 0 ° to 10 °. The rod-like liquid crystal compound may be obliquely aligned. Even in the case of oblique alignment, the average inclination angle is preferably 0 ° to 20 °. In addition, when the wavelength dependency of Re of the first optically anisotropic layer is large, the light leakage of black display of the liquid crystal display device is increased and the contrast is lowered, so that the wavelength dependency is small. Is preferred. From the visual evaluation, it is particularly preferable that the value obtained by dividing Re at the wavelength of 478 nm by Re at the wavelength of 748 nm is 1.00 or more and 1.11 or less. Among these, it is preferably 1.00 or more and 1.10 or less, more preferably 1.00 or more and 1.09 or less, and most preferably 1.00 or more and 1.08 or less.
The first optically anisotropic layer is a layer exhibiting optical anisotropy expressed by the orientation of rod-like liquid crystalline molecules, and this layer controls the orientation of not only rod-like liquid crystalline compounds but also liquid crystalline molecules. It may contain a material that contributes to this, a material that is necessary for fixing the liquid crystal molecules in an aligned state, and the like. Further, the rod-like liquid crystalline molecules may lose liquid crystallinity after being fixed in the alignment state.

  Polymerizable rod-like liquid crystalline molecules include those described in Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 5,622,648 and 5,770,107, World Patents (WO) 95/22586, 95/24455. No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, and JP-A-2001-2001. The aromatic ring contained in the rod-like liquid crystal molecule can be selected from the compounds described in Japanese Patent No. 328973 and the like, but in order to reduce the wavelength dependency of Re of the first optical anisotropic layer. Are preferably not conjugated to other aromatic rings, double bonds or triple bonds in the molecule. Particularly preferred are compounds of the following general formula (I) and general formula (II).

In the general formulas (I) and (II), A ¹ and A ² each represent a substituent, m and n are each an integer of 0 to 4, and B ¹ and B ² are each a substituent, At least one of B ¹ and B ² contains a polymerizable group. C ¹ in the formula (I) is a divalent group that is not conjugated with the benzene ring in the general formula (I) and does not contain a condensed aromatic ring (for example, naphthalene ring) in which aromatic rings are condensed with each other. . Also, D ¹ in the formula (II) is, D ¹ is includes a saturated 6-membered ring, fused aromatic ring in which a benzene ring and aromatic rings are fused (e.g., naphthalene ring) containing no, and wherein It is a divalent group that is not conjugated with the benzene ring therein. In this specification, “a divalent group that is not conjugated to a benzene ring” means a divalent group that is not bonded to the benzene ring through multiple bonds.

In the general formulas (I) and (II), A ¹ and A ² each represent a substituent, for example, a halogen atom, an alkyl group (including a cycloalkyl group such as a cycloalkyl group or a bicycloalkyl group), an alkenyl group (Including cycloalkenyl groups such as cycloalkenyl groups and bicycloalkenyl groups), alkynyl groups, aryl groups, heterocyclic groups, cyano groups, hydroxyl groups, nitro groups, carboxyl groups, alkoxy groups, aryloxy groups, silyloxy groups, hetero Ring oxy group, acyloxy group, carbamoyloxy group, alkoxycarbonyloxy group, aryloxycarbonyloxy, amino group (including anilino group), acylamino group, aminocarbonylamino group, alkoxycarbonylamino group, aryloxycarbonylamino group, sulfo Famoylamino Alkyl, arylsulfonylamino group, mercapto group, alkylthio group, arylthio group, heterocyclic thio group, sulfamoyl group, sulfo group, alkyl and arylsulfinyl group, alkyl and arylsulfonyl group, acyl group, aryloxycarbonyl group, alkoxycarbonyl Examples include groups, carbamoyl groups, aryl and heterocyclic azo groups, imide groups, phosphino groups, phosphinyl groups, phosphinyloxy groups, phosphinylamino groups and silyl groups. A halogen atom, an alkyl group, and an alkoxy group are preferable, and a fluorine atom, a chlorine atom, a bromine atom, a methyl group, an ethyl group, and a methoxy group are particularly preferable. These exemplified substituents may be further substituted with the above exemplified substituents.

In the formulas (I) and (II), m and n are each an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1. When m and n are integers of 2 or more, the plurality of A ¹ and A ² may be the same or different.

In the formulas (I) and (II), B ¹ and B ² each represent a substituent, and each preferably represents an alkyl group, an alkoxy group, an alkoxycarbonyl group, or an acyloxy group. The number of carbon atoms contained in these substituents is preferably 1-15, and more preferably 1-10. These substituents may be further substituted, and examples of the substituents in that case are the same as those given as examples of A ¹ and A ² . At least one of B ¹ or B ² has a polymerizable group. It is preferred that both B ¹ and B ² contain a polymerizable group. By orienting the molecules of the compound represented by the general formula (I) or (II) and then polymerizing, an optically anisotropic layer comprising the compound of the general formula (I) or (II) is formed. be able to. As the polymerizable group, a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group is preferable. Examples of the polymerizable ethylenically unsaturated group include the following (M-1) to (M-6).

  In the formula, R represents a hydrogen atom or a substituent. A hydrogen atom or an alkyl group is preferable, and a hydrogen atom or a methyl group is particularly preferable. Among the above examples, (M-1) or (M-2) is preferable, and (M-1) is most preferable. A cyclic ether group is preferable as the ring-opening polymerizable group, and an epoxy group or an oxetane group is more preferable, and an epoxy group is most preferable.

In order to prevent the degree of orientational order of molecules from being lowered during polymerization and to prevent the film surface from being disturbed, it is preferable to have a flexible spacer portion between the polymerizable group and the mesogen. Examples of the flexible spacer include — (CH ₂ ) _m1 —, — (CH ₂ CH ₂ O) _n1 — and the like. In the formula, m1 represents an integer of 1 to 10, and n1 represents an integer of 1 to 4.

In the above formula, preferred as B ¹ and B ² are groups represented by the following general formula (B).
Formula (B) -LM
In the formula (B), M is a polymerizable group, L is —CH ₂ CH ₂ — (M), —O (CH ₂ ) _x — (M), —COO (CH ₂ ) _x — (M), _{-OCO (CH 2) x - (} M), - OCOO (CH 2) x - (M), - CH 2 CH 2 OCO (CH 2) x - (M), - OCH 2 COO (CH 2) x - (M), —OCH ₂ C≡CCH ₂ — (M), —OCOOCH ₂ C≡CCH ₂ — (M), —C≡C— (CH ₂ ) _x — (M), —CH ₂ CH ₂ —O - (M), - O ( CH 2) x -O- (M), - COO (CH 2) x -O- (M), - OCO (CH 2) x -O- (M), - OCOO ( _{CH 2) x -O- (M)} , - CH 2 CH 2 OCO (CH 2) x -O- (M), - OCH 2 COO (CH 2) x -O- (M), - OCH 2 C≡ _{CCH 2 -O- (M), -} OCOOCH 2 C≡ CH ₂ -O- (M) or -C≡C- (CH ₂₎ a divalent group represented by _x -O- (M). In the formula, x is a natural number of 1 to 10. Among these, —O (CH ₂ ) _x — (M) is most preferable.

Preferable examples of C ^{1 in} the general formula (I) include the following (C-1) to (C-14). In the following formulae, Ar represents a benzene ring in formula (I) (including B ¹ , B ² , A ¹ and A ² which are substituents on the benzene ring).

  Among these, (C-2), (C-4), (C-5), (C-7), (C-11) and (C-14) are particularly preferable.

Preferable examples of D ^{1 in} the general formula (II) include (D-1) to (D-7) shown below. In the following formulas, Ar represents a benzene ring in formula (II) (including B ¹ and A ¹ on the benzene ring), B ² represents a B ² in formula (II).

  Of these, (D-3) and (D-6) are particularly preferred.

  As the rod-like liquid crystalline compound forming the first optically anisotropic layer, a compound represented by the following general formula (III) or general formula (IV) is particularly preferable.

In the general formulas (III) and (IV), A ¹ , A ² , m, n, B ¹ and B ² have the same meanings as those in the general formula (I), and preferred ranges thereof are also the same. .

When C ¹ in the general formula (I) or D ¹ in the formula (II) contains a 1,4-cyclohexane-diyl group (for example, a compound represented by the general formula (III)) The two substituents bonded to the 1- and 4-positions of the cyclohexane ring may be bonded to the cis position, the trans position, or a mixture thereof. However, it is preferably bonded to the trans position.

  Moreover, it is preferable that the compounds represented by the general formulas (I) to (IV) independently have liquid crystallinity, but they can be used together with other liquid crystal compounds even if they do not have liquid crystallinity alone. An optically anisotropic layer may be formed by use and orientation. Further, at the time of immobilization, the compounds represented by the general formulas (I) to (IV) may be polymerized singly, or those compounds or those compounds and other polymerizable liquid crystal compounds or A non-liquid crystalline polymerizable compound may be polymerized.

  Specific examples of the compounds represented by the general formulas (I) to (IV) are shown below, but the present invention is not limited thereto.

  The compounds represented by the general formulas (I) to (IV) are trans-1,4-cyclohexanedicarboxylic acid chloride (described later) using commercially available reagents or compounds synthesized using known methods. The compound can be easily synthesized by a method of reacting with the compound (4-d)) and the like, and further modifying as necessary.

In the formula, A ¹ and m are as defined in the general formulas (I) and (II), R is a hydrogen atom or a substituent, and the substituent is, for example, an alkyl group or an aryl group. Specific synthesis examples are shown below.

1) Synthesis of compound (I-4)

In a nitrogen stream, 20 g (110 mmol) of 6-bromo-1-hexanol, 36.48 g (331 mmol) of hydroquinone and 45.75 (331 mmol) of potassium carbonate were dissolved in 200 ml of dimethylformamide and stirred at 80 ° C. for 3 hours. . The reaction mixture was poured into ice-hydrochloric acid and extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. Purification by silica gel column chromatography gave 13 g (61.8 mmol) of compound (4-a).
9.25 g (44 mmol) of compound (4-a) was dissolved in 100 ml of chloroform, and 3.53 g (44 mmol) of sulfuryl chloride was added and stirred for 1 hour. The solution was concentrated under reduced pressure and purified by silica gel column chromatography to obtain 9.7 g (39.6 mmol) of compound (4-b).

  9.7 g (39.6 mmol) of the compound (4-b) was dissolved in 50 ml of tetrahydrofuran, 6.02 ml (47.52 mmol) of dimethylaniline was added with ice cooling, and then 3.38 ml (41.62 ml) of acryloyl chloride. Mmol) was added. The mixture was stirred at room temperature for 2 hours, poured into ice-hydrochloric acid, and extracted with ethyl acetate. The organic layer was washed with water, dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. Purification by silica gel column chromatography gave 10.1 g (33.81 mmol) of compound (4-C). 3.53 g (20.5 mmol) of trans-1,4-cyclohexanedicarboxylic acid was suspended in 15 ml of toluene, 0.2 ml of dimethylformamide was added, and the mixture was heated to 60 ° C. 3.15 ml (43.2 mmol) of thionyl chloride was added, heated at 60 ° C. for 3 hours, then heated at 110 ° C. for 10 minutes, allowed to cool, and trans-1,4-cyclohexanedicarboxylic acid chloride (4-d ) Was obtained.

3.56 g (11.9 mmol) of compound (4-c) was dissolved in 10 ml of chloroform, 571 mg (14.3 mmol) of sodium hydride was added, and the mixture was stirred for 15 minutes. Thereto was added dropwise 4 ml of the above toluene solution of (4-d). The mixture was stirred for 1 hour, washed with aqueous hydrochloric acid, dehydrated with anhydrous magnesium sulfate, and concentrated under reduced pressure. Purification by silica gel column chromatography gave 2.71 g (3.7 mmol) of compound (I-4).
NMR (CDCl ₃ ): δ = 7.05 to 6.85 (br, 4H), 6.80 (d, 2H), 6.40 (d, 2H), 6.14 (dd, 2H), 5. 81 (d, 2H), 4.15 (t, 4H), 3.90 (t, 4H), 2.68 (m, 2H), 2.31 (m, 4H), 2.00 to 1.30 (M, 20H).
C 73 ° C. N 86 ° C. I.

2) Synthesis of Compound (I-27) Compound (I-27) was prepared according to Aust. J. et al. Cmem. 38 (11), 1705-1718 (1985), and was synthesized in the same manner as compound (I-4) using bicyclooctanedicarboxylic acid synthesized as a starting material.
NMR (CDCl ₃ ): δ = 6.96 (s, 2H), 6.97 (d, 2H), 6.80 (d, 2H), 6.40 (d, 2H), 6.14 (dd, 2H), 5.82 (d, 2H), 4.17 (t, 4H), 3.92 (t, 4H), 2.09 (s, 12H), 1.90 to 1.55 (m, 8H) ) 1.53-1.40 (m, 8H)
Cr 69 ° C. N 103 ° C. I.
Other compounds can be synthesized in the same manner.

[Second optically anisotropic layer]
In the present invention, the second optically anisotropic layer has negative refractive index anisotropy, Re is 10 nm or less, and Rth is 60 to 250 nm with respect to visible light. Preferably, Re is 8 nm or less and Rth is 80 to 200 nm. For the production of the second optically anisotropic layer of the present invention, it is preferable to use a discotic liquid crystalline compound or a polymer. The discotic liquid crystalline compound is preferably aligned substantially horizontally (average inclination angle in the range of 0 to 10 degrees) with respect to the polymer film surface. The discotic liquid crystalline compounds are disclosed in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J Am.Chem.Soc., Vol.116, page 2655 (1994)). The polymerization of the discotic liquid crystalline compound is described in JP-A-8-27284.

The discotic liquid crystalline compound preferably has a polymerizable group so that it can be fixed by polymerization. For example, a structure in which a polymerizable group is bonded as a substituent to a disk-shaped core of a disk-shaped liquid crystalline compound can be considered. However, when a polymerizable group is directly bonded to a disk-shaped core, the alignment state can be maintained in the polymerization reaction. It becomes difficult. Therefore, a structure having a linking group between the discotic core and the polymerizable group is preferable. That is, the discotic liquid crystalline compound having a polymerizable group is preferably a compound represented by the following general formula (V).
General formula (V)
D (-LP) _n
In the formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12.

  Preferred specific examples of the discotic core (D), the divalent linking group (L) and the polymerizable group (P) in the formula (V) are (D1) described in JP-A No. 2001-4837, respectively. To (D15), (L1) to (L25), and (P1) to (P18), and the contents described in the publication can be preferably used. As specific examples of the discotic liquid crystalline compound, those described in WO01 / 88574A1 on page 58, line 6 to page 65, line 8 are also preferable.

  Even when a discotic liquid crystalline compound having a polymerizable group is used, it is preferable to substantially horizontally align the molecules. Substantially horizontal means that the average angle (average inclination angle) between the disk surface of the discotic liquid crystalline compound molecule and the surface of the optically anisotropic layer is in the range of 0 ° to 10 °. The molecules of the discotic liquid crystalline compound may be obliquely aligned. Even in the case of oblique alignment, the average inclination angle is preferably 0 ° to 20 °.

  The high molecular polymer preferably used for the second optically anisotropic layer may be any polymer as long as it has an optically negative refractive index anisotropy, but from the viewpoint of Re being 10 nm with respect to visible light. , Polyolefins such as cellulose acylate, ZEONEX, ZEONOR (both manufactured by Nippon Zeon Co., Ltd.), and ARTON (manufactured by JSR Co., Ltd.) are preferably used. Other examples include non-birefringent optical resin materials as described in JP-A-8-110402 or JP-A-11-293116.

[Fixation of alignment state of liquid crystalline compounds]
When the first and second optically anisotropic layers are formed from a liquid crystal compound, it is preferable to fix the aligned liquid crystal compound molecules while maintaining the alignment state. The immobilization is preferably carried out by a polymerization reaction of a polymerizable group introduced into the liquid crystal compound. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator, and a photopolymerization reaction is more preferable. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

It is preferable that the usage-amount of a photoinitiator is 0.01-20 mass% of solid content of a coating liquid, and it is further more preferable that it is 0.5-5 mass%. Light irradiation for the polymerization of the liquid crystalline compound is preferably performed using ultraviolet rays. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

  The optically anisotropic layer is preferably formed by applying a coating liquid containing a liquid crystalline compound and the above polymerization initiator and other additives onto the alignment film. As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

[Alignment film]
When the first and second optically anisotropic layers are formed from a liquid crystal compound, it is preferable to use an alignment film in order to align the molecules of the liquid crystal compound. The alignment film may be an organic compound (preferably polymer) rubbing treatment, oblique deposition of an inorganic compound, formation of a layer having a microgroup, or an organic compound (eg, ω-triconic acid) by the Langmuir-Blodgett method (LB film). , Dioctadecyldimethylammonium chloride, methyl stearylate, etc.). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known. An alignment film formed by a polymer rubbing treatment is particularly preferred. The rubbing process is carried out by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth.

The type of polymer used for the alignment film can be determined according to the alignment (particularly the average tilt angle) of the liquid crystalline molecules. For example, in order to align liquid crystalline molecules horizontally, a polymer that does not decrease the surface energy of the alignment film (ordinary alignment polymer) is used. Specific types of polymers are described in various documents about liquid crystal cells or optical compensation sheets. In particular, in the present invention, when the liquid crystalline molecules are aligned in a direction orthogonal to the rubbing treatment direction, the modified polyvinyl alcohol described in JP-A No. 2002-62427 and JP-A No. 2002-98836 are described. Acrylic acid-based copolymers, polyimides described in JP-A No. 2002-268068, and polyamic acid can be preferably used. Any of the alignment films preferably has a polymerizable group for the purpose of improving the adhesion between the liquid crystal compound and the transparent support. The polymerizable group can be introduced by introducing a repeating unit having a polymerizable group in the side chain or as a substituent of a cyclic group. It is more preferable to use an alignment film that forms a chemical bond with the liquid crystal compound at the interface. Such an alignment film is described in JP-A-9-152509.
The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 2 μm. In addition, after aligning the liquid crystalline molecules using the alignment film, the liquid crystalline molecules are fixed in the aligned state to form an optically anisotropic layer, and only the optically anisotropic layer is polymer film (or transparent support) It may be transferred onto the body).

Next, the polarizing film used in the liquid crystal display device of the present invention will be described in detail.
[Polarizing film]
The polarizing film that can be used in the present invention is not particularly limited, and conventionally known polarizing films can be used. For example, films made of hydrophilic polymers such as polyvinyl alcohol, partially formalized polyvinyl alcohol, partially saponified ethylene / vinyl acetate copolymer, dichroic dyes such as iodine and / or azo, anthraquinone and tetrazine A material obtained by adsorbing a dichroic material composed of the above material and subjecting it to stretching and orientation can be used. In the present invention, it is preferable to use the stretching method described in JP-A No. 2002-131548, and in particular, a width direction uniaxial stretching type tenter stretching machine in which the absorption axis of the polarizing film is substantially perpendicular to the longitudinal direction. It is preferable to use it. By using a uniaxial stretching type tenter stretching machine in the width direction, there is no need to use an alignment film that aligns the liquid crystalline compound in a direction orthogonal to the direction of the rubbing treatment as the alignment film used for the first optical anisotropic layer. Since an ordinary alignment film is used, it is preferable in terms of cost and defects due to alignment.

The polarizing film is usually used as a polarizing plate having at least one surface protected by a transparent protective film (also referred to as a protective film). The kind of transparent protective film is not particularly limited, and cellulose esters such as cellulose acetate, cellulose acetate butyrate, and cellulose propionate, polycarbonate, polyolefin, polystyrene, polyester, and the like can be used.
The transparent protective film is usually supplied in a roll form, and it is preferable that the transparent protective film is continuously bonded to the long polarizing film so that the longitudinal directions thereof coincide with each other. Here, the orientation axis (slow axis) of the transparent protective film may be any direction, but the orientation axis of the transparent protective film is preferably parallel to the longitudinal direction for ease of operation. Further, the angle between the slow axis (orientation axis) of the transparent protective film and the absorption axis (stretching axis) of the polarizing film is not particularly limited, and can be appropriately set according to the purpose of the polarizing plate.
In addition, when producing a polarizing film using the width direction uniaxial stretching type tenter stretching machine preferably used in the present invention, the slow axis (alignment axis) of the transparent protective film and the absorption axis (stretching) of the polarizing film are used. Axis) will be substantially orthogonal.

  The retardation of the transparent protective film is, for example, preferably 10 nm or less at 632.8 nm, and more preferably 5 nm or less. From the viewpoint of low retardation, the polymer used as the transparent protective film is preferably a polyolefin such as cellulose acylate, ZEONEX, ZEONOR (both manufactured by Nippon Zeon Co., Ltd.), or ARTON (manufactured by JSR Co., Ltd.). Used. Other examples include non-birefringent optical resin materials as described in JP-A-8-110402 or JP-A-11-293116. When cellulose acetate is used for the transparent protective film, the retardation is preferably less than 3 nm, and more preferably 2 nm or less, for the purpose of reducing the change in retardation due to environmental temperature and humidity.

  In the present invention, for the purpose of reducing the thickness, one of the protective films of the polarizing film may also serve as the support for the optically anisotropic layer, or the optically anisotropic layer itself. The optically anisotropic layer and the polarizing film are preferably subjected to a fixing treatment from the viewpoint of preventing displacement of the optical axis and preventing entry of foreign matters such as dust. An appropriate method such as an adhesive method through a transparent adhesive layer can be applied to the fixed lamination. There is no particular limitation on the type of the adhesive and the like, and from the viewpoint of preventing changes in the optical properties of the constituent members, those that do not require a high-temperature process during curing or drying are preferable, and a long-time curing process is preferable. And those that do not require drying time. From such a viewpoint, a hydrophilic polymer adhesive or a pressure-sensitive adhesive layer is preferably used.

  For the formation of the pressure-sensitive adhesive layer, for example, a transparent pressure-sensitive adhesive using an appropriate polymer such as an acrylic polymer, a silicone-based polymer, polyester, polyurethane, polyether, or synthetic rubber can be used. Among these, acrylic pressure-sensitive adhesives are preferred from the viewpoints of optical transparency, adhesive properties, weather resistance, and the like. In addition, an adhesion layer can also be provided as needed on one side or both sides of a polarizing plate for the purpose of adhesion to an adherend such as a liquid crystal cell. In that case, when the pressure-sensitive adhesive layer is exposed on the surface, it is preferable to temporarily attach a separator or the like to prevent contamination of the pressure-sensitive adhesive layer surface until it is put to practical use.

Appropriate functions such as a protective film for various purposes such as water resistance in accordance with the above-mentioned transparent protective film, an antireflection layer and / or an antiglare treatment layer for the purpose of preventing surface reflection, etc. on one or both sides of the polarizing film You may use the polarizing plate in which the layer was formed. The antireflection layer can be suitably formed, for example, as a light interference film such as a fluorine polymer coating layer or a multilayer metal vapor deposition film. The antiglare layer is also formed by an appropriate method that diffuses the surface reflected light, for example, by providing a fine uneven structure on the surface by an appropriate method such as a resin coating layer containing fine particles, embossing, sandblasting or etching. can do.
Examples of the fine particles include inorganic materials having an average particle diameter of 0.5 to 20 μm, such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide. One kind or two or more kinds of fine particles, such as crosslinked or uncrosslinked organic fine particles made of a suitable polymer such as polymethyl methacrylate and polyureta can be used. The above-mentioned adhesive layer or pressure-sensitive adhesive layer may contain such fine particles and exhibit light diffusibility.

[Optical performance of polarizing plate]
The optical properties and durability (short-term and long-term storage stability) of a polarizing plate comprising a transparent protective film, a polarizing film and a transparent support related to the present invention are commercially available super high contrast products (for example, Sanritz Corporation). Manufactured by HLC2-5618 and the like) and preferably have equivalent or better performance. Specifically, the visible light transmittance is 42.5% or more, and the degree of polarization ({(Tp−Tc) / (Tp + Tc)} ^1/2 ≧ 0.9995 (where Tp is parallel transmittance and Tc is orthogonal) The change rate of the light transmittance before and after leaving for 500 hours in a 60 ° C., 90% humidity RH atmosphere and 500 ° C. in a dry atmosphere for 500 hours is 3% based on the absolute value. In the following, it is further preferable that the change rate of the polarization degree is 1% or less, further 0.1% or less based on the absolute value.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

[Example 1]
A liquid crystal display device having the configuration shown in FIG. 1 was produced. That is, the upper polarizing plate 1, the liquid crystal cell (upper substrate 5, liquid crystal layer 7, lower substrate 8), and lower polarizing plate 12 were laminated from the observation direction (upper layer), and a backlight light source (not shown) was further arranged. A first optical anisotropic layer 3 and a second optical anisotropic layer 10 for improving the optical performance of the liquid crystal display device were disposed between the upper and lower polarizing plates and the liquid crystal cell. As the upper polarizing plate 1 and the lower polarizing plate 12 used, from the configuration shown in FIG. 2, the protective film 101, the polarizing film 103, and the protective film 105 (assuming that the protective film 105 is disposed closer to the liquid crystal cell). For the upper polarizing plate 1, an integrated upper polarizing plate in which the protective film 105 is also used as a transparent support for the first optical anisotropic layer 3 and the optical anisotropic layer 3 is integrated. After producing the plate, it was incorporated into a liquid crystal display device. For the lower polarizing plate 14, the protective film 105 was also used as the second optical anisotropic layer 10.

Below, the manufacturing method of each used member is demonstrated.
<Production of liquid crystal cell>
A VA mode liquid crystal cell was prepared by the following procedure. After applying an alignment film (for example, JALS204R manufactured by JSR Corporation) to the substrate surface, the tilt angle with respect to the so-called substrate surface, which is a director indicating the alignment direction of liquid crystalline molecules, was set to about 89 ° by rubbing treatment. The cell gap between the upper and lower substrates is 3.5 μm, and a liquid crystal having a negative dielectric anisotropy and Δn = 0.0813 and Δε = −4.6 (for example, MLC-6608 manufactured by Merck) is dropped. And sealed.

<Production of integrated upper polarizing plate>
A polarizing film was prepared by adsorbing iodine to a stretched polyvinyl alcohol film. A commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) subjected to saponification treatment was used for the transparent protective film (101 in FIG. 2) on the side far from the liquid crystal cell. The protective film had an Re value of 3 nm and an Rth value of 50 nm. On the other hand, the transparent support A prepared by the following method and saponified was used for the transparent protective film (105 in FIG. 2) on the side close to the liquid crystal cell.

(Preparation of transparent support A)
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution.
Cellulose acetate solution composition Cellulose acetate having an acetylation degree of 60.7 to 61.1% 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Methylene chloride (first Solvent) 336 parts by mass Methanol (second solvent) 29 parts by mass

  In another mixing tank, 16 parts by mass of the following retardation increasing agent, 92 parts by mass of methylene chloride and 8 parts by mass of methanol were added and stirred while heating to prepare a retardation increasing agent solution. A dope was prepared by mixing 474 parts by mass of the cellulose acetate solution with 25 parts by mass of the retardation increasing agent solution and stirring sufficiently. The addition amount of the retardation increasing agent was 3.5 parts by mass with respect to 100 parts by mass of cellulose acetate.

The obtained dope was cast using a band stretching machine. After the film surface temperature on the band reached 40 ° C., the film was dried with warm air of 70 ° C. for 1 minute, and the film from the band was dried with 140 ° C. drying air for 12 minutes, and the residual solvent amount was 0.3% by mass. A cellulose acetate film (thickness: 80 μm) was prepared. About the produced cellulose acetate film, Re value and Rth value in wavelength 550nm were measured using the ellipsometer (M-150, JASCO Corporation make). Re was 2 nm (variation ± 1 nm), and Rth was 120 nm (variation ± 3 nm). Furthermore, Re of each wavelength of 400 nm to 700 nm was in the range of 2 ± 1 nm, and Rth of each wavelength of 400 nm to 700 nm was in the range of 120 ± 2 nm.
The produced cellulose acetate film was immersed in a 2.0 mol / l potassium hydroxide solution (25 ° C.) for 2 minutes, neutralized with sulfuric acid, washed with pure water, and then dried. The surface energy of the cellulose acetate film was determined by a contact method and found to be 63 mN / m. The cellulose acetate film thus prepared was used as a transparent support A.

(Formation of alignment film)
Next, 26.3 ml / m ² of a coating solution having the following composition was applied to the surface of the produced transparent support A with a # 15 wire bar coater.
Composition film coating liquid composition 4 parts by mass of the following polymer compound P 3 parts by mass Triethylamine 2 parts by mass 5% aqueous solution of DECONAL EX-521 (epoxy compound of Nagase Kasei Kogyo Co., Ltd.) 8.1 parts by mass Water 57 parts by mass Methanol 29 parts by mass

  Drying was performed at 25 ° C. for 30 seconds and 120 ° C. warm air for 120 seconds. The thickness of the alignment film after drying was 1.0 μm. Further, the surface roughness of the alignment film was measured with an atomic force microscope (AFM: Atomic Force Microscope, SPI3800N, manufactured by Seiko Instruments Inc.) and found to be 1.135 nm. Next, the formed film was rubbed in the same direction as the slow axis 106 (longitudinal direction: wavelength 550 nm measurement) of the transparent support A.

(Formation of first optically anisotropic layer)
A first optically anisotropic layer was formed on this alignment film. Specifically, a coating solution having the following composition is continuously coated on the alignment film using a bar coater, dried, and heated (alignment aging), and further irradiated with ultraviolet rays to a thickness of 0.8 μm. The first optically anisotropic layer with horizontal orientation was formed.
First coating composition for optically anisotropic layer Rod-like liquid crystalline compound (Exemplary Compound I-4) in the present specification 32.1% by mass
Sensitizer A 0.32% by mass
The following photopolymerization initiator B 0.96% by mass
Orientation control agent C 0.19 mass%
Glutaraldehyde 0.04% by mass
Chloroform 66.39% by mass

  The formed first optically anisotropic layer 3 had a slow axis 4 in a direction orthogonal to the longitudinal direction (rubbing direction) of the transparent support A, and the Re value at 550 nm was 60 nm. Moreover, optically positive refractive index anisotropy was exhibited. When the wavelength dependency of Re was measured using KOBRA-31PR manufactured by Oji Scientific Instruments, the value obtained by dividing Re at a wavelength of 478 nm by Re at a wavelength of 748 nm was 1.07.

  The laminated body of the produced transparent support A and the first optically anisotropic layer, and the cellulose triacetate film Fujitac TD80UF were attached to both sides of the produced polarizing film using a polyvinyl alcohol-based adhesive, and integrated. An upper polarizing plate was produced. In FIG. 2, the transparent protective film 101 far from the liquid crystal cell side is Fujitac TD80UF, and the transparent protective film 105 near the liquid crystal cell is the transparent support A. When the stacking angle of each film is based on the left and right directions when the display device is viewed from above (0 °), the angle of the upper polarizing plate protective film slow axis 102 and 106 is 0 °, and the polarizing film absorption axis 104 ( In FIG. 1, the angle of 2) was 0 °. The integrated upper polarizing plate of the upper polarizing plate 1 and the first optically anisotropic layer 3 manufactured in this way is arranged so that the first optically anisotropic layer 3 is closer to the upper liquid crystal cell substrate 5. Incorporated into a liquid crystal display device.

<Preparation of lower polarizing plate>
The same polarizing film as the upper polarizing plate produced above was used. As the transparent protective film (101 in FIG. 2) on the side farther from the liquid crystal cell of the polarizing film, a commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd.) was used as in the upper polarizing plate. It was. On the other hand, as the transparent protective film (105 in FIG. 2) on the side close to the liquid crystal cell, the transparent support A produced above was used in the same manner as the upper polarizing plate. Two types of protective films were attached to both surfaces of the polarizing film using the same adhesive as described above. When the stacking angle of each film is based on the left and right directions when the display device is viewed from above (0 °), the axis angle of the polarizing film absorption axis 104 (13 in FIG. 1) is 90 ° in FIG. The angles of the protective film slow axes 102 and 106 were set to 90 °.
Since the transparent support A has an optically negative refractive index anisotropy and exhibits optical characteristics of Re = 2 nm and Rth = 120 nm with respect to visible light, the second optical anisotropic layer Also worked. Therefore, the produced polarizing plate composed of the protective film and the polarizing film was used as a lower polarizing plate in which the lower polarizing plate 12 and the second optically anisotropic layer 10 in FIG. 1 were integrated. This lower polarizing plate was incorporated in a liquid crystal display device so that the second optically anisotropic layer 10 was closer to the lower liquid crystal cell substrate 8.

<Measurement of leakage light of the manufactured liquid crystal display device>
The viewing angle dependence of the transmittance of the liquid crystal display device thus manufactured was measured. The elevation angle was measured from the front in an oblique direction up to 80 ° every 10 °, and the azimuth was measured up to 360 ° every 10 ° on the basis of the horizontal right direction (0 °). It has been found that the luminance at the time of black display increases as the elevation angle increases from the front direction, and the leakage light transmittance also increases and takes a maximum value near the elevation angle of 60 °. It was also found that the contrast, which is the ratio between the white display transmittance and the black display transmittance, deteriorates as the black display transmittance increases. Therefore, it was decided to evaluate the viewing angle characteristics based on the maximum values of the black display transmittance at the front and the leakage light transmittance at an elevation angle of 60 °.
The front transmittance in this example was 0.02%, and the leakage light transmittance at an elevation angle of 60 ° was 0.035% at an azimuth angle of 45 °.

[Example 2]
A liquid crystal display device having the configuration shown in FIG. 1 was produced. That is, the upper polarizing plate 1, the liquid crystal cell (upper substrate 5, liquid crystal layer 7, lower substrate 8), and lower polarizing plate 12 were laminated from the observation direction (upper layer), and a backlight light source (not shown) was further arranged. A first optical anisotropic layer 3 and a second optical anisotropic layer 10 for improving the optical performance of the liquid crystal display device were disposed between the upper and lower polarizing plates and the liquid crystal cell. As the upper polarizing plate 1 and the lower polarizing plate 12 used, from the configuration shown in FIG. 2, the protective film 101, the polarizing film 103, and the protective film 105 (assuming that the protective film 105 is disposed closer to the liquid crystal cell). For the upper polarizing plate 1, an integrated upper polarizing plate in which the protective film 105 is also used as a transparent support for the first optical anisotropic layer 3 and the optical anisotropic layer 3 is integrated. After producing the plate, it was incorporated into a liquid crystal display device. For the lower polarizing plate 12 as well, the protective film 105 is also used as a transparent support for the second optically anisotropic layer 10 to produce an integrated lower polarizing plate in which the optically anisotropic layer 10 is integrated. After that, it was incorporated into a liquid crystal display device.

The same liquid crystal cell and polarizing film as in Example 1 were used.
As the protective film for the upper and lower polarizing films, as in Example 1, a commercially available cellulose triacetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re value is 3 nm, Rth value is 50 nm) was used.

<Production of integrated upper polarizing plate>
An alignment film layer and a first optical anisotropic layer 3 were formed on Fujitac TD80UF (Re = 3 nm, Rth = 50 nm) subjected to the same saponification treatment as that of the transparent support of Example 1. The rod-like liquid crystal compound was aligned (slowed in the same manner as in Example 1 except that the Re value at 550 nm of the first optical anisotropic layer was increased to 85 nm by increasing the thickness of the first optical anisotropic layer 3. The first optical anisotropic layer 3 was formed by setting the phase axis to a direction perpendicular to the slow axis of the support. The first optically anisotropic layer exhibited optically positive refractive index anisotropy. A value obtained by dividing Re at a wavelength of 478 nm by Re at a wavelength of 748 nm was 1.07.
The laminate of the produced Fujitac TD80UF and the first optically anisotropic layer 3 and Fujitac TD80UF were attached to both surfaces of the polarizing film using a polyvinyl alcohol-based adhesive to produce an integrated upper polarizing plate. This integrated upper polarizing plate was incorporated in a liquid crystal display device so that the first optical anisotropic layer 3 was closer to the upper liquid crystal cell substrate 5.

<Preparation of integrated lower polarizing plate>
(Preparation of alignment layer)
On Fujitac TD80UF (Re = 3 nm, Rth = 50 nm) subjected to the same saponification treatment as that of the transparent support of Example 1, a coating solution having the following composition was applied at 28 ml / m ² with a # 16 wire bar coater. .
Alignment film coating solution composition Modified polyvinyl alcohol 20 parts by weight Water 361 parts by weight Methanol 119 parts by weight Glutaraldehyde (crosslinking agent) 0.5 parts by weight

  Drying was performed at 25 ° C. for 60 seconds, 60 ° C. warm air for 60 seconds, and 90 ° C. warm air for 150 seconds. The alignment film thickness after drying was 1.1 μm. Further, the surface roughness of the alignment film was measured with an atomic force microscope (AFM: Atomic Force Microscope, SPI3800N, manufactured by Seiko Instruments Inc.), and found to be 1.147 nm. The alignment film was rubbed in the same direction as the slow axis of Fujitac TD-80UF.

(Formation of second optically anisotropic layer)
A coating liquid containing a discotic liquid crystal having the following composition was applied on the alignment film subjected to the rubbing treatment.
Composition of coating liquid for discotic liquid crystal layer Discotic liquid crystalline compound (1) * 1 32.6% by mass
Cellulose acetate butyrate 0.7% by mass
Ethylene oxide modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 3.2% by mass
Sensitizer (Kayacure DETX, manufactured by Nippon Kayaku Co., Ltd.) 0.4% by mass
Photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) 1.1% by mass
Methyl ethyl ketone 62.0% by mass
* 1: As the discotic liquid crystalline compound (1), 1,2,1 ′, 2 ′, 1 ″, 2 ″ -tris [4,5-di (vinylcarbonyloxybutoxybenzoyloxy) phenylene Exemplified compound TE-8 (8), m = 4) described in JP-A-8-50206, paragraph 0044 was used.

  Then, it dried by heating for 2 minutes in a 130 degreeC drying zone, and the disk shaped compound was orientated. Next, using a 120 W / cm high pressure mercury lamp at 130 ° C., UV irradiation was performed for 4 seconds to polymerize the discotic compound. Thereafter, the film was allowed to cool to room temperature, a thickness of 1.4 μm, an optically negative refractive index anisotropy, and a second optical anisotropic layer with Re = 0 nm and Rth = 140 nm for visible light Formed. The discotic liquid crystalline compound of the second optically anisotropic layer was horizontally aligned within a range of ± 2 °.

The laminated body of Fujitac TD80UF and the second optically anisotropic layer and Fujitac TD80UF thus produced were attached to both surfaces of the polarizing film using a polyvinyl alcohol-based adhesive to produce an integrated polarizing plate.
The produced integrated lower polarizing plate was incorporated into a liquid crystal display device so that the second optical anisotropic layer 10 was in contact with the upper liquid crystal cell substrate 8.
A liquid crystal display device was fabricated in the same manner as in Example 1 for other configurations.

<Measurement of leakage light of the manufactured liquid crystal display device>
The viewing angle characteristics of leaked light at the time of black display of the liquid crystal display device thus manufactured were measured by the same method as in Example 1. The front transmittance in this example was 0.02%, and the leakage light transmittance at an elevation angle of 60 ° was 0.035% at an azimuth angle of 45 °.

[Example 3]
A liquid crystal display device was produced in the same manner as in Example 2 except that the rod-like liquid crystal compound used for production of the first optically anisotropic layer was replaced with Exemplified Compound I-27. The formed first optically anisotropic layer had optically positive refractive index anisotropy, and Re at a wavelength of 550 nm was 61 nm. The value obtained by dividing Re at a wavelength of 478 nm by Re at a wavelength of 748 nm was 1.07. The measured value of leakage light of the manufactured liquid crystal display device was the same as in Example 2.

[Comparative Example 1]
A liquid crystal display device was produced in the same manner as in Example 1 except that the first optically anisotropic layer 3 was not formed in the production of the integrated upper polarizing plate of Example 1.
<Measurement of leakage light of the manufactured liquid crystal display device>
The viewing angle characteristics of leaked light at the time of black display of the liquid crystal display device thus manufactured were measured by the same method as in Example 1. The front transmittance in this comparative example was 0.02%, and the leakage light transmittance at an elevation angle of 60 ° was 0.35% at an azimuth angle of 45 °. In Examples 1, 2 and 3 of the present invention, the leakage light is remarkably smaller than that of the present comparative example, and the effect of the embodiment of the present invention is clear.

[Comparative Example 2]
As the transparent protective film on the side close to the liquid crystal cell of the upper polarizing plate 1, a transparent protective film having an Re value of 36 nm and an Rth value of 173 nm is used, and the angle of the slow axis of the protective film outside the upper polarizing plate 1 is 0 °. The same as Example 1 except that the angle of the film absorption axis 2 was set to 0 °, the angle of the slow axis of the liquid crystal cell side protective film was set to 90 °, and the first optically anisotropic layer 3 was not produced. Thus, an upper polarizing plate was produced. Similarly, as the transparent protective film on the side close to the liquid crystal cell of the lower polarizing plate 12, a film having an Re value of 9 nm and an Rth value of 68 nm is used, and the angle of the protective film slow axis outside the lower polarizing plate is set to 90 °. A lower polarizing plate was produced in the same manner as in Example except that the angle of the polarizing film absorption axis 13 was set to 90 ° and the angle of the liquid crystal cell side protective film slow axis was set to 0 °. A liquid crystal display device was produced in the same manner as in Example 1 except that these upper and lower polarizing plates were used.

<Measurement of leakage light of the manufactured liquid crystal display device>
The viewing angle characteristics of leaked light at the time of black display of the liquid crystal display device thus manufactured were measured by the same method as in Example 1. The front transmittance in this comparative example was 0.02%, and the leakage light transmittance at an elevation angle of 60 ° was 0.17% at an azimuth angle of 45 °. In Examples 1, 2 and 3 of the present invention, the leakage light is remarkably smaller than that of the present comparative example, and the effect of the embodiment of the present invention is clear.

[Comparative Example 3]
A liquid crystal display device having the same configuration as in FIG. 1 was produced. 2 are used as the polarizing plates 1 and 12, and as the protective films 101 and 105, a commercially available cellulose acetate film (Fujitac TD80UF, manufactured by Fuji Photo Film Co., Ltd., Re value is 3 nm, Rth value is 50 nm. ) Was used. Further, between the upper polarizing plate 1 and the upper liquid crystal cell substrate 5, there is one retardation film C (3 in FIG. 1) made of a stretched film, and the lower polarizing plate 12 and the lower liquid crystal cell substrate 8. In the middle, two retardation films D made of stretched films (indicated as 10 in FIG. 1 as one) are arranged. The direction of the slow axis and polarizing plate absorption axis of the polarizing plate protective film was the same as in Example 2. The retardation film C is made of a norbornene-based stretched film, and the average refractive index in the stretching direction of the film surface is Nx (= 1.51), and the average refractive index in the direction perpendicular to the stretching direction of the film surface is Ny (= 1.1. 509), the average refractive index in the thickness direction of the film surface was Nz (= 1.509), and the thickness of the film was 95 μm. The Re value of the film was 95 nm, and the angle of the slow axis 4 was 0 °. On the other hand, the retardation film D (10) is made of a norbornene-based stretched film, the average refractive index in the stretching direction of the film surface is Nx (= 1.51), and the average refractive index in the direction perpendicular to the stretching direction of the film surface. Ny (= 1.51), the average refractive index in the thickness direction of the film surface was Nz (= 1.5084), and the thickness of the film was 70 μm. The film has a Re value of 5 nm and an Rth value of 110 nm, and is laminated so that the slow axes of the two films are substantially perpendicular to each other. The angle of the slow axis of the film in contact with the lower polarizing plate is 90 °. The film was in contact with the cell so that the slow axis angle was 0 °.

<Measurement of leakage light of the manufactured liquid crystal display device>
The viewing angle characteristics of leakage light at the time of black display of the liquid crystal display device thus manufactured were measured by the same method as in Example 1. The front transmittance in this comparative example was 0.02%, and the leakage light transmittance at an elevation angle of 60 ° was 0.17% at an azimuth angle of 45 °. In Examples 1, 2 and 3 of the present invention, the leakage light is remarkably smaller than that of the present comparative example, and the effect of the embodiment of the present invention is clear.

[Comparative Example 4]
A liquid crystal display device was produced in the same manner as in Example 2 except that the rod-like liquid crystal compound of the first optically anisotropic layer was changed to the following rod-like liquid crystal A. The value obtained by dividing Re at the wavelength of 478 nm by Re at the wavelength of 748 nm of the first optically anisotropic layer was 1.20. The measured value of leakage light of the manufactured liquid crystal display device was the same as in Example 2. The maximum value of leakage light transmittance at a front transmittance of 0.02% and an elevation angle of 60 ° was 0.06% at an azimuth angle of 45 °. In Examples 1, 2 and 3 of the present invention, the leakage light is smaller than that of the comparative example, and the effect of the embodiment of the present invention is clear.

It is the schematic which shows an example of the liquid crystal display device of this invention. It is the schematic which shows an example of the polarizing plate which can be used for this invention.

Explanation of symbols

1 Upper polarizing plate 2 Upper polarizing plate absorption axis 3 First optical anisotropic layer 4 First optical anisotropic layer slow axis direction 5 Upper electrode substrate of liquid crystal cell 6 Upper substrate alignment control direction 7 Liquid crystalline molecule 8 Liquid crystal cell lower electrode substrate 9 Lower substrate orientation control direction 10 Second optical anisotropic layer 11 Second optical anisotropic layer slow axis direction 12 Lower polarizing plate 13 Lower polarizing plate absorption axis direction 101 Polarization Plate protective film 102 Polarizing plate protective film direction of slow axis 103 Polarizing plate polarizing film 104 Polarizing film absorption axis direction 105 Polarizing plate protective film 106 Polarizing plate protective film slow axis direction

Claims (3)

Two polarizing films whose absorption axes are orthogonal to each other, and a liquid crystal layer composed of a pair of substrates and liquid crystal molecules sandwiched between the two polarizing films, and an external electric field in non-driving state but not applied, a liquid crystal cell wherein liquid crystal molecules are aligned in a direction substantially perpendicular to the substrate, optically has a positive refractive index anisotropy, the following general formula (III) Or a first optically anisotropic layer formed from a composition containing a compound represented by the following general formula (IV) , wherein Re defined by the following formula (1) is 40 to 150 nm with respect to visible light At least one of the above, optically negative refractive index anisotropy, Re defined below for visible light is 10 nm or less, and Rth defined by the following formula (2) is 60 to 250 nm Liquid crystal display having at least one second optically anisotropic layer apparatus.

(In the formula, A ¹ and A ² each represent a substituent, m and n are each an integer of 0 to 4, B ¹ and B ² are each a substituent, and at least one of B ¹ and B ² is polymerized. Contains a sex group.)

(In the formula, A ¹ and A ² each represent a substituent, m and n are each an integer of 0 to 4, B ¹ and B ² are each a substituent, and at least one of B ¹ and B ² is polymerized. Contains a sex group.)
Re = (nx−ny) × d (1)
Rth = {(nx + ny) / 2−nz} × d (2)
(Where nx is the refractive index in the slow axis direction in the plane of the layer, ny is the refractive index in the plane perpendicular to nx, nz is the refractive index in the thickness direction of the layer, and d is the thickness of the layer) .) 2. The liquid crystal display device according to claim 1, wherein a value obtained by dividing Re at a wavelength of 478 nm of the first optical anisotropic layer by Re at a wavelength of 748 nm is 1.00 or more and 1.11 or less. The second optical anisotropic layer, a liquid crystal display device according to claim 1 or 2 is a layer formed from a composition containing a discotic liquid crystal compound having a polymerizable group.

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