JP2006091626A - Optical compensation film, elliptic polarizing plate and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical compensation film and an elliptic polarizing plate which are used for providing a liquid crystal display device that has improved gradation inversion and the characteristic of a wider viewing angle and is excellent in industrial productivity. <P>SOLUTION: The optical compensation film is characterized in that a liquid crystal composition which develops a biaxial nematic phase is twisted hybrid oriented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical compensation film having an optically anisotropic layer formed from liquid crystalline molecules, an elliptically polarizing plate using the same, and a liquid crystal display device.

The liquid crystal display device includes a liquid crystal cell, a polarizing element, and an optical compensation film (retardation plate).
In the transmissive liquid crystal display device, two polarizing elements are arranged on both sides of the liquid crystal cell, and one or two optical compensation films are arranged between the liquid crystal cell and the polarizing element. In a reflective liquid crystal display device, a reflector, a liquid crystal cell, a single optical compensation film, and a single polarizing element are arranged in this order. The liquid crystal cell is composed of a rod-like liquid crystal molecule, two substrates for enclosing it, and an electrode layer for applying a voltage to the rod-like liquid crystal molecule. The liquid crystal cell is different in the alignment state of rod-like liquid crystal molecules. As for the transmissive type, TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), OCB (Optically Compensatory Bend), STN (STN) Various display modes such as TN, HAN (Hybrid Aligned Nematic), and GH (Guest-Host) have been proposed for Supper Twisted Nematic (VA), VA (Vertically Aligned), ECB (Electrically Controlled Birefringence), and reflective types. .

  Optical compensation films have been used in various liquid crystal display devices in order to eliminate image coloring and expand the viewing angle. As the optical compensation film, an optical compensation film having an optically anisotropic layer formed from a liquid crystalline molecule on a transparent support, such as a stretched birefringent polymer film, is generally used. The optical properties of the optical compensation film are determined according to the optical properties of the liquid crystal cell, specifically, the difference in the display mode as described above.

  When liquid crystalline molecules are used, optical compensation films having various optical properties corresponding to various display modes of the liquid crystal cell can be produced. Optical compensation films using liquid crystal molecules have already been proposed for various display modes.

  A retardation plate using a biaxial liquid crystal, particularly a retardation plate in which biaxial liquid crystals are hybrid-aligned is useful for viewing angle compensation of a liquid crystal display device. (For example, refer to Patent Documents 1 and 2). In order to realize such a state where the biaxial liquid crystal is hybrid-aligned, it is necessary to develop a biaxial nematic phase (Nb phase).

  However, an optical compensation film in which a liquid crystal composition that expresses a biaxial nematic phase is hybrid-aligned can realize a wide viewing angle characteristic, but when viewing the display surface of a display device from below, it can be viewed from the normal direction of the display surface. As the angle increases, the luminance difference between the gradation levels forming the image decreases abruptly, causing a phenomenon that some gradation levels are inverted (gray-scale inversion). It was necessary to suppress this gradation inversion.

JP 2002-174730 A JP 2002-207125 A

An object of the present invention is to provide gradation inversion that occurs when a compensation film in which a liquid crystal composition expressing a biaxial nematic phase having a wide and excellent viewing angle characteristic is hybrid-aligned is used in a liquid crystal display device such as a TN mode. (When viewing the display surface of the display device from below, as the angle from the normal direction of the display surface increases, the brightness difference of each gradation level forming the image decreases sharply and some gradation levels are inverted. It is to provide an optical compensation film with reduced phenomenon.
Another object is to provide an elliptically polarizing plate and a liquid crystal display device using the compensation film.

The object of the present invention described above has been achieved by the following invention.
1. An optical compensation film having an optically anisotropic layer containing a liquid crystal composition exhibiting a biaxial nematic phase in a state of giving a hybrid alignment and a twist alignment.
2. An optical compensation film having an optically anisotropic layer formed from a liquid crystal composition that exhibits a biaxial nematic phase, wherein the optically anisotropic layer has a biaxial nematic phase imparting a twisted orientation to a hybrid orientation. An optical compensation film formed by being fixed.
3. When the refractive index in the triaxial direction of the liquid crystal composition expressing the biaxial nematic phase is nx, ny, and nz in descending order, the angle formed by nx and the plane direction of the film hardly changes in the thickness direction, and 3. The optical compensation film as described in 1 or 2 above, wherein an angle formed between nz and the surface direction of the film changes in the thickness direction.
4). 4. The optical compensation film as described in any one of 1 to 3 above, wherein the twist angle is less than 10 degrees.
5). 5. The optical compensation film according to any one of 1 to 4, wherein the liquid crystal composition expressing a biaxial nematic phase includes a liquid crystal compound expressing a rod-like liquid crystal phase and a liquid crystal compound expressing a discotic liquid crystal phase.
6). The liquid crystal composition containing an optically active compound and a liquid crystal compound that expresses a biaxial nematic phase is laminated on a support coated with an alignment film, and then the biaxial nematic phase is expressed and immobilized. The optical compensation film according to any one of the above.
7). 7. An elliptically polarizing plate, wherein the optical compensation film according to any one of 1 to 6 and a polarizing film are laminated on a transparent support.
8). 7. A liquid crystal display device using the optical compensation film according to any one of 1 to 6 or the elliptically polarizing plate according to 7 above.

  For example, when the optical compensation film disclosed in the present invention is provided between the TN liquid crystal cell and the upper and lower polarizing films, gradation inversion occurring in the lower direction of the TN liquid crystal display device is improved, and a wider viewing angle is obtained. The characteristics can be realized. Provided optical compensation film and elliptically polarizing plate with excellent industrial productivity by twisting hybrid alignment of liquid crystal composition expressing biaxial nematic phase, and improved display quality compared to conventional It became possible to make a display device.

  Hereinafter, the contents of the present invention will be described in detail. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

  When performing phase compensation of the liquid crystal layer, the optical compensation film is used by inserting, laminating, and optically adhering between the polarizing film and the liquid crystal layer. It is useful to form an elliptically polarizing plate in which a layer and a transparent support are bonded and bonded.

  The film of the present invention is realized by twisting the hybrid alignment of the liquid crystal composition expressing a biaxial nematic phase.

The main refractive indexes in the three orthogonal directions of the biaxial nematic phase are nx, ny, and nz in descending order.
Hybrid orientation means that the directions of nx, ny, and nz continuously change in the film thickness direction with respect to the thickness of the layer. FIG. 1A is a schematic diagram showing this. The twisted orientation means that the directions of the main refractive indices nx, ny, and nz continuously rotate and change in the plane with respect to the thickness of the layer. FIG. 1B is a schematic diagram showing this.
The tilt angle of the hybrid orientation and the twist angle of the twist orientation increase or decrease with an increase in the depth direction of the optically anisotropic layer and the distance from the transparent support interface. The tilt angle and twist angle are preferably increased with increasing distance. In addition, changes in tilt angle and twist angle include continuous increase, continuous decrease, intermittent increase, intermittent decrease, change including continuous increase and continuous decrease, or intermittent change including increase and decrease. Is possible. The intermittent change includes a region where the inclination angle and the twist angle do not change in the middle of the thickness direction. In the present invention, even if a region where the tilt angle and the twist angle do not change is included, it may be increased or decreased as a whole. Furthermore, it is preferable that the inclination angle and the twist angle change continuously.

  The optical compensation film of the present invention preferably has an optically anisotropic layer formed from a liquid crystal composition expressing a biaxial nematic phase on a transparent support. More preferably, an alignment film is provided between the transparent support and the optically anisotropic layer. The optically anisotropic layer is formed by adding other additives to the liquid crystal composition expressing a biaxial nematic phase as necessary, and applying the composition on the alignment film, and then fixing the alignment in the liquid crystal state. can get. At this time, the liquid crystal composition expressing the biaxial nematic phase is fixed in a state where the twist alignment is given to the hybrid alignment.

  As the hybrid orientation of the biaxial nematic phase, assuming that the refractive indexes in the three orthogonal directions are nx, ny, and nz in descending order, (i) the hybrid in which the nx and ny directions change in the film thickness direction and the nz direction does not change. (Ii) Hybrid orientation in which the nx and nz directions change in the film thickness direction and the ny direction does not change, (iii) Hybrid orientation in which the ny and nz directions change in the film thickness direction and the nx direction does not change To do. Considering the viewing angle compensation of the liquid crystal display device, since there are preferred and unfavorable orientations among such orientations, not all of the hybrid orientations are generally preferred. In this, the phase plate is made to be TN (Twisted). In the case of using as a viewing angle compensator for a liquid crystal display device in a Nematic mode or an OCB (Optically Compensatory Bend) mode, (iii) the hybrid orientation in which the ny and nz directions change in the film thickness direction and the nx direction does not change is the most. preferable.

Since the biaxial nematic phase is preferably coated on the support (more preferably on the alignment film), the liquid crystal compound is formed on the support surface or the coating film interface (or the alignment film if an alignment film is provided). Orientation is performed at the tilt angle of the interface (in other words, the angle formed with the surface direction of the transparent support), and at the interface with air, the orientation is performed at the tilt angle of the air interface. In the case of a biaxial liquid crystal compound, there are three types of tilt angles: a tilt angle formed between the nx direction and the interface, a tilt angle formed between the ny direction and the interface, and a tilt angle formed between the nz direction and the interface (the tilt angle is based on the interface). And).
In the present invention, the tilt angle in the nx direction of the optically anisotropic layer is such that the tilt angle at the air interface and the support side interface is 0 to 10 degrees, preferably 0 to 5 degrees, and preferably hardly changes in the film thickness direction. .
On the other hand, in the ny direction, the tilt angle between the air interface and the support side interface is greatly different. Therefore, in the film thickness direction, the tilt angle continuously changes from the air interface side toward the support side interface side. The tilt angle in the ny direction is preferably such that the tilt angle at the air interface is 3 degrees or more and 87 degrees or less, and the tilt angle at the support side interface is 3 degrees or more and 87 degrees or less. In particular, the average tilt angle β of the tilt angle is preferably 30 ° or more and 75 ° or less, more preferably 35 ° or more and 72 ° or less, and particularly preferably 40 ° or more and 70 ° or less.
Since the nz direction is orthogonal to the ny direction, the tilt angle in the nz direction is such that the tilt angle at the air interface is not less than 3 degrees and not more than 87 degrees, and the tilt angle at the support side interface is not less than 3 degrees and not more than 87 degrees. preferable. In particular, the average tilt angle β of the tilt angle is preferably 15 degrees or more and 60 degrees or less, more preferably 18 degrees or more and 55 degrees or less, and particularly preferably 20 degrees or more and 50 degrees or less.
That is, since the tilt angle of the air interface and the support side interface is different in the ny direction and the nz direction, hybrid alignment is performed.

The other optical characteristics of the optically anisotropic layer are not particularly limited, and a preferable range is determined depending on the application to be used.
The film thickness is preferably 0.01 μm or more and less than 50 μm, and more preferably 0.1 μm or more and less than 5 μm. In general, the in-plane retardation Re is preferably 10 to 120 nm, and more preferably 30 to 90 nm. The retardation Rth in the thickness direction is preferably 20 to 200 nm.
(Nx−nz) / (nx−ny) of the biaxial nematic phase is preferably 1.01 or more and less than 100, more preferably 1.2 or more and less than 40, and further preferably 2.0 or more and less than 30.
The larger nx-ny and ny-nz of the biaxial nematic phase is preferable because the film thickness can be reduced and the coating property can be improved, preferably 0.001 or more, more preferably 0.01 or more, and more preferably 0.03 or more. Further preferred.

  As a method for obtaining the refractive index in the three directions of the liquid crystal phase, for example, a report by Sakai (“Method of analyzing birefringence of a film using an automatic birefringence meter” Plastics, Vol. 51, No. 3, 57 (2000) ) Can be helpful.

Various forms of twist orientation are possible. The angle of twist is preferably 0.1 degrees or more and less than 10 degrees, more preferably 0.25 degrees or more and less than 5 degrees, and more preferably 0.5 degrees or more and less than 4 degrees with respect to the liquid crystal cell side as a reference point. Further preferred.
The twist orientation in the optically anisotropic layer is preferably less than 1 pitch. The direction of twist orientation may be clockwise or counterclockwise, but the twist orientation is opposite to the twist direction of the liquid crystal in the liquid crystal cell to be optically compensated.

As a method for imparting a twisted alignment, it is possible to develop a biaxial nematic phase having a twisted orientation by mixing an optically active compound with a liquid crystal compound that exhibits a biaxial nematic phase. The twist-aligned biaxial nematic phase can also be expressed by using a liquid crystal compound having an asymmetric center.
As the optically active compound, a known chiral agent (for example, liquid crystal device handbook, Chapter 3-4-3, TN, chiral agent for STN, 199 pages, edited by Japan Society for the Promotion of Science, 142nd Committee, 1989) is used. be able to. The optically active compound generally contains an asymmetric carbon atom, but an axially asymmetric compound or a planar asymmetric compound that does not contain an asymmetric carbon atom can also be used as a chiral agent. Examples of the axial asymmetric compound or the planar asymmetric compound include binaphthyl, helicene, paracyclophane, and derivatives thereof. The optically active compound (chiral agent) may have a polymerizable group.
The amount of the optically active compound used is preferably 0.01 to 200 mol% of the amount of the liquid crystal compound that exhibits a biaxial nematic phase.

  When the direction of the optically anisotropic layer in which the liquid crystal composition expressing the biaxial nematic phase is hybrid-aligned is defined as the direction in which the nx direction is projected into the support surface, the combination with the absorption axis direction of the polarizing film is It can be selected from either substantially parallel or orthogonal. Here, “substantially parallel or orthogonal” means that the deviation is preferably within 20 degrees, more preferably within 10 degrees. It is preferable that they are orthogonal.

Hereinafter, although the example of the optical compensation film of this invention is shown, the order of the layer to laminate | stack etc. is not restrict | limited to this. FIG. 2 is a schematic diagram showing a basic configuration of a transmissive liquid crystal display device. The transmissive liquid crystal display device shown in FIG. 2A has a transparent protective film (1a), a polarizing film (2a), a transparent support (3a), an optically anisotropic layer (in order from the backlight (BL) side). 4a), lower substrate (5a) of liquid crystal cell, rod-like liquid crystalline molecule (6), upper substrate (5b) of liquid crystal cell, optical anisotropic layer (4b), transparent support (3b), polarizing film (2b) And a transparent protective film (1b).
The transparent protective film, the polarizing film, the transparent support, and the optically anisotropic layer (1a to 4a and 4b to 1b) constitute an optical compensation film.

  The transmissive liquid crystal display device shown in FIG. 2B has a transparent protective film (1a), a polarizing film (2a), a transparent support (3a), an optically anisotropic layer (in order) from the backlight (BL) side. 4a), from the lower substrate (5a) of the liquid crystal cell, the rod-like liquid crystal molecule (6), the upper substrate (5b) of the liquid crystal cell, the transparent protective film (3b), the polarizing film (2b), and the transparent protective film (1b) Become. A transparent protective film, a polarizing film, a transparent support, and an optically anisotropic layer (1a-4a) comprise an elliptically polarizing plate.

  The transmissive liquid crystal display device shown in FIG. 2C has a transparent protective film (1a), a polarizing film (2a), a transparent protective film (3a), and a lower substrate of a liquid crystal cell (from the backlight (BL) side). 5a), rod-like liquid crystalline molecules (6), upper substrate (5b) of liquid crystal cell, optical anisotropic layer (4b), transparent support (3b), polarizing film (2b), and transparent protective film (1b) Become. The optically anisotropic layer and the transparent support constitute an optical compensation film. And a transparent protective film, a polarizing film, a transparent support body, and an optically anisotropic layer (1b-4b) comprise an elliptically polarizing plate.

FIG. 3 is a schematic diagram showing a basic configuration of a reflective liquid crystal display device. The reflective liquid crystal display device shown in FIG. 2 includes, in order from the bottom, the lower substrate (5a) of the liquid crystal cell, the reflector (7), the rod-like liquid crystal molecule (6), the upper substrate (5b) of the liquid crystal cell, and the optical anisotropic. It consists of a conductive layer (4b), a transparent support (3b), a polarizing film (2b), and a transparent protective film (1b).
The transparent support and the optically anisotropic layer (4b to 3b) constitute an optical compensation film. And a transparent protective film, a polarizing film, a transparent support body, and an optically anisotropic layer (4b-1b) comprise an elliptically polarizing plate.

  For example, the tilt angle of the hybrid orientation of the film and the magnitude of the twist angle of the twist orientation are determined by measuring ellipsometry from various directions, and the Extended Jones method (for example, P. Yeh et al., Optics of liquid crystal displays, 1999). It can be obtained by comparing with the simulation by year, page 306). The film thickness can also be obtained by calculating in combination with the refractive index of the liquid crystal.

[Liquid crystal composition]
The liquid crystal composition used in the present invention exhibits a biaxial nematic phase. The biaxial nematic phase is a kind of liquid crystal phase that can be taken by the nematic liquid crystal compound. When the space of the liquid crystal phase is defined by the x axis, the y axis, and the z axis, the liquid crystal compound (liquid crystal molecule) is y. This shows a state in which free rotation of the xz plane around the axis and free rotation of the xy plane around the z axis are prohibited. A biaxial nematic phase is preferable because it easily aligns liquid crystal molecules and hardly causes alignment defects.

The liquid crystal composition that expresses a biaxial nematic phase in the present invention contains a compound that expresses liquid crystal (a liquid crystal compound). The liquid crystal compound may be a liquid crystal compound that expresses one type of biaxial nematic phase, or a liquid crystal compound that expresses two or more types of biaxial nematic phases. For example, a polymerizable biaxial liquid crystal compound and a non-polymerizable biaxial liquid crystal compound can be used in combination. It is also possible to use a low-molecular liquid crystal compound and a high-molecular liquid crystal compound in combination. Furthermore, it is also possible to use a biaxial liquid crystal mixture that expresses a biaxial liquid crystal phase by mixing two or more compounds that do not express a biaxial liquid crystal phase alone. The liquid crystal compound may be a low molecular compound or a high molecular compound.
Further, in addition to the liquid crystal compound, an additive (for example, an air interface alignment controller, a repellency inhibitor, a polymerization initiator, a polymerizable monomer, a solvent, etc.) that can be added in forming the optically anisotropic layer described later may be included. Good.

  Specific examples of the low-molecular liquid crystal compound that can be preferably used in the present invention are shown below, but the present invention is not limited thereto.

  It is preferable that the liquid crystal compound exhibiting a biaxial nematic phase can easily control the value of (nx−nz) / (nx−ny) of the biaxial liquid crystal phase. From such a point, a liquid crystal compound that exhibits a biaxial nematic phase is different from a liquid crystal compound that exhibits a rod-like liquid crystal phase in which the value of (nx−nz) / (nx−ny) can be easily controlled as described later. A mixed liquid crystal compound of a liquid crystal compound expressing a tick liquid crystal phase is preferable, and a mixed liquid crystal compound of a liquid crystal compound expressing a nematic phase and a liquid crystal compound expressing a discotic nematic phase is particularly preferable.

[Liquid crystal compound exhibiting rod-like liquid crystal phase]
Examples of the rod-like liquid crystal phase include a nematic phase, a smectic A phase, a smectic C phase, and the like in which a liquid crystal compound having a rod-like or plate-like shape is developed. Since such a liquid crystal phase has a relationship of nx> ny = nz, it is a uniaxial liquid crystal phase having positive birefringence. Details are described in Chapter 2 of the Liquid Crystal Handbook (issued in Maruzen Co., Ltd. 2000), and in the present invention, the nematic phase is particularly preferable as the rod-like liquid crystal phase.

  On the other hand, a liquid crystal phase in which it is difficult to determine whether the liquid crystal is a uniaxial liquid crystal or a biaxial liquid crystal is also known. For example, D.D. Demus, J. et al. Goodby et al. [Handbook of Liquid Crystals Vol. 2B: Low Molecular Weight Liquid Crystals II, pp 933-943: published by WILEY-VCH] can be said to be a difficult liquid crystal phase. Liquid crystal compounds that exhibit rod-like liquid crystals include such compounds that are difficult to determine uniaxial and biaxial.

  The liquid crystal compound that exhibits a rod-like liquid crystal phase may be a low-molecular liquid crystal compound or a high-molecular liquid crystal compound, but the low-molecular liquid crystal compound is more compatible with a liquid crystal compound that exhibits a discotic liquid crystal phase. preferable.

  The liquid crystal compound exhibiting a rod-like liquid crystal phase is preferably a liquid crystal compound exhibiting a uniaxial liquid crystal phase having positive birefringence, and examples of the compound include azomethines, azoxys, cyanobiphenyls, cyano Mention may be made of phenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenyl cyclohexanes, cyano substituted phenyl pyrimidines, alkoxy substituted phenyl pyrimidines, phenyl dioxanes, tolanes and alkenyl cyclohexyl benzonitriles. .

  A liquid crystal compound that exhibits a rod-like liquid crystal phase is a substituent that can form a substituent or a covalent bond that can interact (for example, a hydrogen bond or a dipole interaction) with a liquid crystal compound that exhibits a discotic liquid crystal phase. It is preferable to have (for example, a polymerizable group). By having such a substituent, when a liquid crystal compound that expresses a rod-like liquid crystal phase and a liquid crystal compound that expresses a discotic liquid crystal phase are mixed, the compatibility of the liquid crystal compounds improves, and each composition It is possible to avoid phase separation for each phase composed of objects. For the same reason, the liquid crystal compound that exhibits a discotic liquid crystal phase preferably has a similar group.

  The liquid crystal compound exhibiting a rod-like liquid crystal phase preferably has a polymerizable group, and more preferably has a polymerizable group at the end of the compound molecule. In addition to preventing phase separation from a liquid crystal compound that exhibits a discotic liquid crystal phase as described above, having a polymerizable group can cause a potential difference due to heat or the like when used in a phase difference plate or the like with the liquid crystal composition of the present invention. Since the change of a phase difference can be prevented, it is preferable.

Examples of the uniaxial liquid crystal compound having a positive birefringence having a polymerizable group 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, International Publications 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, JP-A-2001-328773, etc. Can be used.
Below, a preferable example is shown as a polymeric group which the liquid crystal compound which expresses a rod-shaped liquid crystal phase has.

  Among the polymerizable groups, unsaturated polymerizable groups (Q1 to Q7), epoxy groups (Q8) or aziridinyl groups (Q9) are more preferable, unsaturated polymerizable groups (Q1 to Q7) are more preferable, and ethylenic properties are preferred. Unsaturated polymerizable groups (Q1 to Q6) are most preferred.

  The shape of the liquid crystal compound that expresses the rod-like liquid crystal phase is not particularly limited, and may be rod-like, plate-like, or other shapes. Among these, a plate shape is preferable from the viewpoint of compatibility with a liquid crystal compound that exhibits a discotic liquid crystal phase and ease of expression of a biaxial nematic phase.

  The above-mentioned liquid crystal compound is “plate-like” when the compound has at least two core parts exhibiting liquid crystallinity alone and is a planar, positive birefringence in which the core parts are connected by a covalent bond. It means that it is a uniaxial liquid crystal compound having For example, in the exemplary compound (m-1) of the present invention described later, the RO-Ph-OR (Ph: benzene ring) portion corresponds to a core portion exhibiting liquid crystallinity alone. The RO-Ph-OR moiety is linked by a covalent bond to give the exemplified compound (m-1).

  More specifically, that the liquid crystal compound is “plate-like” means the following. That is, when the longest side of the rectangular parallelepiped inscribed in the stabilization structure of the liquid crystal compound and having the smallest volume is L1, the middle side is Lm, and the shortest side is Ls, the liquid crystal compound is “plate-shaped”. , Ll / Lm> 1.1 and Lm / Ls> 1.5. The most stable structure of the liquid crystal compound can be determined by MOPAC (semi-empirical molecular orbital calculation program). Specifically, the MOPAC AM1 method (software used: WinMOPAC, distributor: Fujitsu Limited) can be used. Good.

  In the present invention, it is preferable that the following formulas (I) and (II) are satisfied as the plate-like shape of the liquid crystal compound exhibiting a rod-like liquid crystal phase.

Formula (I): 1.2 <Ll / Lm <10
Formula (II): 2.0 <Lm / Ls <10

As a liquid crystal compound having a plate shape, Mol. Cry. Liq. Cry. , 323, 231 (1998), "Dyes and Drugs" Vol. 42, No. 4, 85 (1997), "Dyes and Drugs" Vol. 42, No. 3, p. 68 (1997) The compounds described in the above, and compounds in which a polymerizable group is introduced into the described compound can be used.
Specific examples of the liquid crystal compound having a plate shape are shown below, but the present invention is not limited thereto.

[Liquid crystal compounds exhibiting a discotic liquid crystal phase]
Examples of the discotic liquid crystal phase include a discotic nematic phase, a columnar phase, and a columnar lamellar phase in which a liquid crystal compound having a disk shape is developed. In the present invention, the discotic liquid crystal phase is particularly preferably a discotic nematic phase.

  On the other hand, a liquid crystal phase in which it is difficult to determine whether the liquid crystal is a uniaxial liquid crystal or a biaxial liquid crystal is also known. For example, D.D. Demus, J. et al. Goodby et al. [Handbook of Liquid Crystals Vol. 2B: Low Molecular Weight Liquid Crystals II, pp 933-943: published by WILEY-VCH] can be said to be a difficult liquid crystal phase. Liquid crystal compounds that exhibit a discotic liquid crystal phase include such compounds that are difficult to determine uniaxial and biaxial.

  The liquid crystal compound that expresses the discotic liquid crystal phase may be a low-molecular liquid crystal compound or a high-molecular liquid crystal compound, but the compatibility between the liquid crystal compound that expresses the discotic liquid crystal phase and the liquid crystal compound that expresses the rod-like liquid crystal phase. In this respect, a low molecular liquid crystal compound is preferable.

  As a liquid crystal compound that exhibits a discotic liquid crystal phase, various documents (C. Destrade et al., Mol. Crys. Liq. Crys., 71, 111 (1981), edited by the Chemical Society of Japan, quarterly chemistry review). No. 22, Chemistry of Liquid Crystal, Chapter 5, Chapter 10, Section 2 (1994), B. Kohne et al., Angew. Chem. Soc. Chem. Comm., 1794 (1985), J Zhanget et al., J. Am.Chem.Soc., 116, 2655 (1994)).

  The liquid crystal compound that exhibits a discotic liquid crystal phase preferably has a polymerizable group, and more preferably has a polymerizable group at the end of the molecule of the compound. Having a polymerizable group not only prevents phase separation from the liquid crystal compound that expresses a rod-like liquid crystal phase, but also changes the phase difference due to heat or the like when used in a phase difference plate or the like with the liquid crystal composition of the present invention. Since it can prevent, it is preferable. A compound represented by the following general formula (D) is particularly preferable.

Formula (D): D (-LQ) n

  In the formula, D is a discotic core, L is a divalent linking group, and Q is a polymerizable group. N is an integer of 3 to 12. The structural formulas of specific examples (D1 to D15) of the general formula (D) are 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). A structure in which LQ (or QL) is deleted from each example is an example of the disk-shaped core (D) of the general formula (D).

  L in the general formula (D) is a divalent group selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —C (═O) —, —NH—, —O—, —S—, and combinations thereof. The linking group is preferably. L is a group obtained by combining at least two divalent groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —C (═O) —, —NH—, —O—, and —S—. More preferably it is. L is most preferably a group obtained by combining at least two divalent groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, -C (= O)-and -O-. The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6 to 10. The alkylene group, alkenylene group and arylene group may have a substituent (eg, alkyl group, halogen atom, cyano group, alkoxy group, acyloxy group).

  Examples of the divalent linking group (L) are shown below. In each formula, 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.

L1: -AL-C (= O) -O-AL-
L2: -AL-C (= O) -O-AL-O-
L3: -AL-C (= O) -O-AL-O-AL-
L4: -AL-C (= O) -O-AL-OC (= O)-
L5: -C (= O) -AR-O-AL-
L6: -C (= O) -AR-O-AL-O-
L7: -C (= O) -AR-O-AL-OC (= O)-
L8: -C (= O) -NH-AL-
L9: -NH-AL-O-
L10: -NH-AL-OC (= O)-
L11: -O-AL-
L12: -O-AL-O-
L13: -O-AL-OC (= O)-

L14: -O-AL-OC (= O) -NH-AL-
L15: -O-AL-S-AL-
L16: -OC (= O) -AL-AR-O-AL-OC (= O)-
L17: -OC (= O) -AR-O-AL-C (= O)-
L18: -OC (= O) -AR-O-AL-OC (= O)-
L19: -OC (= O) -AR-O-AL-O-AL-OC (= O)-
L20: -OC (= O) -AR-O-AL-O-AL-O-AL-OC (= O)-
L21: -S-AL-
L22: -S-AL-O-
L23: -S-AL-OC (= O)-
L24: -S-AL-S-AL-
L25: -S-AR-AL-

The polymerizable group (Q) of the general formula (D) is not particularly limited. When polymerizing the present invention, it can be determined according to the type of polymerization reaction.
Preferred specific examples of the polymerizable group (Q) are the same as those described in the liquid crystal compound that exhibits a rod-like liquid crystal phase, and more preferred polymerizable groups (Q) are the same as those of the liquid crystal compound that exhibits a rod-like liquid crystal phase. is there.

  In the general formula (D), n is an integer of 3 to 12. A specific number is determined according to the type of the disk-shaped core (D). In particular, n is preferably an integer of 3 to 6, and n is most preferably 3. In addition, although the combination of several L and Q may differ, it is preferable that it is the same.

  Two or more kinds of discotic liquid crystal compounds may be used in combination as the compound having a disk shape. For example, a molecule having a polymerizable group (Q) and a molecule not having it may be used in combination.

  The non-polymerizable discotic liquid crystal compound is preferably a compound in which the polymerizable group (Q) of the polymerizable discotic liquid crystal compound described above is changed to a hydrogen atom or an alkyl group. That is, the non-polymerizable discotic liquid crystal compound is preferably a compound represented by the following formula.

  D (-LR) n

  In the formula, D is a discotic core, L is a divalent linking group, and R is a hydrogen atom or an alkyl group. N is an integer of 3 to 12. The example of the discotic core (D) of the above formula is the same as the example of the polymerizable discotic liquid crystal compound except that LQ (or QL) is changed to LR (or RL). Examples of the divalent linking group (L) are the same as the examples of the polymerizable discotic liquid crystal compound. The alkyl group for R preferably has 1 to 40 carbon atoms, and more preferably 1 to 30 carbon atoms. A chain alkyl group is preferred to a cyclic alkyl group, and a linear alkyl group is preferred to a branched chain alkyl group. R is particularly preferably a hydrogen atom or a linear alkyl group having 1 to 30 carbon atoms.

  As the liquid crystal compound exhibiting a discotic liquid crystal phase used in the present invention, a compound represented by the following general formula (I) is most preferable.

In the general formula (I), Y ₁₁ , Y ₁₂ , Y ₁₃ , Y ₂₁ , Y ₂₂ , Y ₂₃ , Y ₂₄ , Y ₂₅ , Y ₂₆ each independently represent a methine or nitrogen atom.

When Y ₁₁ , Y ₁₂ , Y ₁₃ , Y ₂₁ , Y ₂₂ , Y ₂₃ , Y ₂₄ , Y ₂₅ , Y ₂₆ is methine, the methine may have a substituent. Examples of the substituent include an alkyl group (eg, methyl group, ethyl group, isopropyl group, tert-butyl group), alkenyl group (eg, vinyl group, allyl group, 2-butenyl group, 3-pentenyl group). ), Alkynyl group (for example, propargyl group, 3-pentynyl group, etc.), aryl group (for example, phenyl group, p-methylphenyl group, naphthyl group, etc.), substituted or unsubstituted amino group (For example, an unsubstituted amino group, a methylamino group, a dimethylamino group, a diethylamino group, an anilino group, etc.), an alkoxy group (for example, a methoxy group, an ethoxy group, a butoxy group, etc.), an aryloxy group ( For example, a phenyloxy group, 2-naphthyloxy group, etc.), an acyl group (for example, acetyl) , Benzoyl group, formyl group, pivaloyl group, etc.), alkoxycarbonyl group (for example, methoxycarbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (for example, phenyloxycarbonyl group, etc.) An acyloxy group (for example, acetoxy group, benzoyloxy group and the like), an acylamino group (for example, acetylamino group, benzoylamino group and the like), an alkoxycarbonylamino group (for example, methoxycarbonylamino group and the like). ), Aryloxycarbonylamino group (for example, phenyloxycarbonylamino group), alkylsulfonylamino group (for example, methanesulfonylamino group), arylsulfonylamino Group (for example, benzenesulfonylamino group), sulfamoyl group (for example, sulfamoyl group, N-methylsulfamoyl group, N, N-dimethylsulfamoyl group, N-phenylsulfamoyl group) Carbamoyl group (for example, unsubstituted carbamoyl group, N-methylcarbamoyl group, N, N-diethylcarbamoyl group, N-phenylcarbamoyl group, etc.), alkylthio group (for example, methylthio group, ethylthio group) ), Arylthio groups (for example, phenylthio groups and the like), alkylsulfonyl groups (for example, mesyl groups and the like), arylsulfonyl groups (for example, tosyl groups and the like), alkylsulfinyl groups (For example, methanesulfinyl group, etc. Arylsulfinyl group (for example, benzenesulfinyl group), ureido group (for example, unsubstituted ureido group, 3-methylureido group, 3-phenylureido group, etc.), phosphoric acid Amide group (for example, diethyl phosphoric acid amide group, phenylphosphoric acid amide group etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group A carboxyl group, a nitro group, a hydroxamic acid group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group (for example, a heterocyclic group having a heteroatom such as a nitrogen atom, an oxygen atom, a sulfur atom, such as an imidazolyl group) , Pyridyl group, quinolyl group, furyl group, piperidyl group, morpholino group, benzoxa Lil group, benzimidazolyl group, etc. benzthiazolyl group), a silyl group (e.g., trimethylsilyl group, etc. triphenylsilyl group) are included. These substituents may be further substituted with these substituents.

  Among these, methine substituents include alkyl groups, alkoxy groups, aryloxy groups, acyl groups, alkoxycarbonyl groups, acyloxy groups, acylamino groups, alkoxycarbonylamino groups, alkylthio groups, arylthio groups, halogen atoms, and cyano. An alkyl group, an alkoxy group, an alkoxycarbonyl group, an acyloxy group, a halogen atom, and a cyano group, more preferably an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and 2 carbon atoms. Most preferred are an alkoxycarbonyl group having 12 to 12 carbon atoms, an acyloxy group having 2 to 12 carbon atoms, a halogen atom and a cyano group.

In general formula (I), X ₁ , X ₂ and X ₃ each independently represent an oxygen atom, a sulfur atom, methylene or imino. When X ₁ , X ₂ , and X ₃ are methylene and imino, they may have a substituent. As the substituent, those mentioned as the substituent for the methine are preferable. These substituents may be further substituted, and the substituents in that case are the same as those mentioned as the substituents that the methine substituent may have.

In general formula (I), L ₁ , L ₂ and L ₃ are each independently a single bond or a divalent linking group. When L ₁ , L ₂ and L ₃ are divalent linking groups, each independently represents —O—, —S—, —C (═O) —, —NR ₇ —, —CH═CH—, —C. It is preferably a divalent linking group selected from the group consisting of ≡C—, a divalent cyclic group, and combinations thereof. R ₇ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and preferably a methyl group, an ethyl group, or a hydrogen atom. More preferably, it is a hydrogen atom.

The divalent cyclic group represented by L ₁ , L ₂ , and L ₃ is a divalent linking group having at least one kind of cyclic structure. The divalent cyclic group is preferably a 5-membered ring, 6-membered ring, or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and most preferably a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, it is more preferably a monocycle than a condensed ring. The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclohexane ring. Examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring. The cyclic group is preferably an aromatic ring or a heterocyclic ring.

Of the divalent cyclic groups represented by L ₁ , L ₂ and L ₃ , 1,4-phenylene is preferred as the cyclic group having a benzene ring. As the cyclic group having a naphthalene ring, naphthalene-1,5-diyl and naphthalene-2,6-diyl are preferable. The cyclic group having a cyclohexane ring is preferably 1,4-cyclohexylene. As the cyclic group having a pyridine ring, pyridine-2,5-diyl is preferable. The cyclic group having a pyrimidine ring is preferably pyrimidine-2,5-diyl.

The divalent cyclic group represented by L ₁ , L ₂ and L ₃ may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 16 carbon atoms, a halogen-substituted alkyl group having 1 to 16 carbon atoms, and an alkoxy group having 1 to 16 carbon atoms. , An acyl group having 2 to 16 carbon atoms, an alkylthio group having 1 to 16 carbon atoms, an acyloxy group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, carbon An alkyl-substituted carbamoyl group having 2 to 16 atoms and an acylamino group having 2 to 16 carbon atoms are included.

L ₁ , L ₂ , and L ₃ include a single bond, * —O—CO—, * —CO—O—, * —CH═CH—, * —C≡C—, * —divalent cyclic group— * -O-CO-divalent cyclic group-, * -CO-O-divalent cyclic group-, * -CH = CH-divalent cyclic group-, * -C≡C-divalent cyclic group Group-, * -divalent cyclic group-O-CO-, * -divalent cyclic group-CO-O-, * -divalent cyclic group-CH = CH-, * -divalent cyclic group- C≡C— is preferred. In particular, a single bond, * —CH═CH—, * —C≡C—, * —CH═CH—divalent cyclic group—, and * —C≡C—divalent cyclic group— are preferable. * Represents a position bonded to a 6-membered ring including Y ₁₁ , Y ₁₂ and Y ₁₃ in the general formula (I).

In the general formula (I), R ₁ , R ₂ and R ₃ are each independently an alkyl group (for example, methyl group, ethyl group, isopropyl group, tert-butyl group) or alkenyl group (for example, vinyl group, allyl group). , 2-butenyl group, 3-pentenyl group and the like), alkynyl group (for example, propargyl group, 3-pentynyl group and the like), aryl group (for example, phenyl group, p-methylphenyl group, naphthyl group) Substituted, unsubstituted amino group (for example, unsubstituted amino group, methylamino group, dimethylamino group, diethylamino group, anilino group, etc.), alkoxy group (for example, methoxy group, ethoxy group) And butoxy groups), aryloxy groups (for example, phenyloxy groups, 2-naphthyloxy groups, etc.). ), An acyl group (for example, acetyl group, benzoyl group, formyl group, pivaloyl group, etc.), an alkoxycarbonyl group (for example, methoxycarbonyl group, ethoxycarbonyl group, etc.), an aryloxycarbonyl group (for example, , Phenyloxycarbonyl group etc.), acyloxy group (eg acetoxy group, benzoyloxy group etc.), acylamino group (eg acetylamino group, benzoylamino group etc.), alkoxycarbonylamino group ( For example, methoxycarbonylamino group and the like), aryloxycarbonylamino group (for example, phenyloxycarbonylamino group and the like), alkylsulfonylamino group (for example, methanesulfonylamino group) Arylsulfonylamino group (for example, benzenesulfonylamino group), sulfamoyl group (for example, sulfamoyl group, N-methylsulfamoyl group, N, N-dimethylsulfamoyl group, N- Phenylsulfamoyl group and the like), carbamoyl group (for example, unsubstituted carbamoyl group, N-methylcarbamoyl group, N, N-diethylcarbamoyl group, N-phenylcarbamoyl group and the like), alkylthio group ( For example, a methylthio group, an ethylthio group, etc.), an arylthio group (for example, a phenylthio group etc.), an alkylsulfonyl group (for example, a mesyl group etc.), an arylsulfonyl group (for example, a tosyl group, etc.) Alkylsulfinini) Group (for example, methanesulfinyl group), arylsulfinyl group (for example, benzenesulfinyl group), ureido group (for example, unsubstituted ureido group, 3-methylureido group, 3-phenylureido group) Etc.), phosphoric acid amide groups (for example, diethylphosphoric acid amide group, phenylphosphoric acid amide group etc.), hydroxy groups, mercapto groups, halogen atoms (for example, fluorine atom, chlorine atom, bromine atom, iodine) Atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (for example, a heterocyclic ring having a heteroatom such as nitrogen atom, oxygen atom, sulfur atom) Groups such as imidazolyl, pyridyl, quinolyl, furyl, Lysyl group, a morpholino group, benzoxazolyl group, benzimidazolyl group, etc. benzthiazolyl group), a silyl group (e.g., trimethylsilyl group, etc. triphenylsilyl group). These substituents may be further substituted with these substituents.

R ₁ , R ₂ and R ₃ are more preferably each independently represented by the following general formula (III).

Formula (III): * -L ₁₁ -Q

In the general formula (III), * represents a position bonded to the 5-membered ring in the general formula (I).
Q is each independently a polymerizable group or a methyl group. In the case where the compound represented by the general formula (I) including the optical compensation film of the present invention is used for an optical film in which the phase difference does not change due to heat as in the optical compensation film, Q is polymerized. It is preferable that it is a sex group. The polymerization reaction is preferably addition polymerization (including ring-opening polymerization) or condensation polymerization. In other words, the polymerizable group is preferably a functional group capable of addition polymerization reaction or condensation polymerization reaction. Examples of polymerizable groups are shown below.

Furthermore, the polymerizable group is particularly preferably a functional group capable of addition polymerization reaction. Such a polymerizable group is preferably a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group.
Examples of the polymerizable ethylenically unsaturated group include the following formulas (M-1) to (M-6).

In formulas (M-3) and (M-4), R represents a hydrogen atom or an alkyl group. R is preferably a hydrogen atom or a methyl group.
Among the above (M-1) to (M-6), (M-1) or (M-2) is preferable, and (M-1) is most preferable.

  The ring-opening polymerizable group is preferably a cyclic ether group, and more preferably an epoxy group or an oxetanyl group, and most preferably an epoxy group.

In the general formula (III), L ₁₁ is a divalent linking group. L ₁₁ is a divalent group selected from the group consisting of —O—, —S—, —C (═O) —, —NR ₇ —, a divalent chain group, a divalent cyclic group, and combinations thereof. A linking group is preferred. R ₇ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and preferably a methyl group, an ethyl group, or a hydrogen atom. More preferably, it is a hydrogen atom.

The divalent chain group represented by L ₁₁ means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, or a substituted alkynylene group. Of these, an alkylene group, a substituted alkylene group, an alkenylene group, and a substituted alkenylene group are preferable, and an alkylene group and an alkenylene group are more preferable.

The alkylene group as the divalent chain group represented by L ₁₁ may have a branch. The alkylene group preferably has 1 to 16 carbon atoms, more preferably 2 to 14 carbon atoms, and most preferably 2 to 12 carbon atoms. The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent include a halogen atom.

The alkenylene group as the divalent chain group represented by L ₁₁ may have a substituted or unsubstituted alkylene group in the main chain, or may have a branch. The alkenylene group preferably has 2 to 16 carbon atoms, more preferably 2 to 14 carbon atoms, and most preferably 2 to 12 carbon atoms. The alkenylene part of the substituted alkenylene group is the same as the above alkenylene group. Examples of the substituent include a halogen atom.

The alkynylene group as the divalent chain group represented by L ₁₁ may have a substituted or unsubstituted alkylene group in the main chain, and the alkynylene group preferably has 2 to 16 carbon atoms. 2 to 14 is more preferable, and 2 to 12 is most preferable. The alkynylene part of the substituted alkynylene group is the same as the above alkynylene group. Examples of the substituent include a halogen atom.

Specific examples of the divalent chain group represented by L ₁₁ include ethylene, trimethylene, tetramethylene, 1-methyl-1,4-butylene, pentamethylene, hexamethylene, octamethylene, nonamethylene, decamethylene and undeca. Examples include methylene, dodecamethylene, 2-butenylene, and 2-butynylene.

The divalent cyclic group represented by L ₁₁ is a divalent linking group having at least one cyclic structure. The divalent cyclic group is preferably a 5-membered ring, 6-membered ring, or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and most preferably a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, it is more preferably a monocycle than a condensed ring. The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclohexane ring. Examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring.

Among the divalent cyclic groups represented by L ₁₁ , 1,4-phenylene is preferable as the cyclic group having a benzene ring. As the cyclic group having a naphthalene ring, naphthalene-1,5-diyl and naphthalene-2,6-diyl are preferable. The cyclic group having a cyclohexane ring is preferably 1,4-cyclohexylene. As the cyclic group having a pyridine ring, pyridine-2,5-diyl is preferable. The cyclic group having a pyrimidine ring is preferably pyrimidine-2,5-diyl.

The divalent cyclic group represented by L ₁₁ may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 16 carbon atoms, a halogen-substituted alkyl group having 1 to 16 carbon atoms, and an alkoxy group having 1 to 16 carbon atoms. , An acyl group having 2 to 16 carbon atoms, an alkylthio group having 1 to 16 carbon atoms, an acyloxy group having 2 to 16 carbon atoms, an alkoxycarbonyl group having 2 to 16 carbon atoms, a carbamoyl group, carbon An alkyl-substituted carbamoyl group having 2 to 16 atoms and an acylamino group having 2 to 16 carbon atoms are included.

R ₁ , R ₂ and R ₃ are more preferably each independently represented by the following general formula (IV).

Formula _{(IV): * - L 21} - divalent cyclic group _-L 22 -Q ₁

In the general formula (IV), * represents a position bonded to the 5-membered ring in the general formula (I).
Q ₁ is the same as the definition of Q in the general formula (III).
L ₂₁ is a single bond or a divalent linking group. When L ₂₁ is a divalent linking group, it consists of —O—, —S—, —C (═O) —, —NR ₇ —, —CH═CH—, —C≡C—, and combinations thereof. A divalent linking group selected from the group is preferred. R ₇ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and preferably a methyl group, an ethyl group, or a hydrogen atom. More preferably, it is a hydrogen atom.

L ₂₁ represents a single bond, and * —O—CO—, * —CO—O—, * —CH═CH—, * —C≡C— (where, * represents * in formula (IV)) Represents the side).

  The divalent cyclic group in general formula (IV) is the same as the definition of the divalent cyclic group in general formula (III).

In the general formula (IV), L ₂₂ is the same as the definition of L _{11 in} the general formula (III).
Examples of the divalent linking group represented by L ₂₂ are shown below. Here, the right side is bonded to the divalent cyclic group in the general formula (IV), and the left side is bonded to Q ₁ .

L-1: -Divalent chain group -O-Divalent cyclic group-
L-2: -Divalent chain group -O-Divalent cyclic group -CO-O-
L-3: -Divalent chain group -O-Divalent cyclic group -O-CO-
L-4: - divalent chain group -O- divalent cyclic group -CO-NR ₇ -
L-5: -Divalent chain group -O-Divalent cyclic group -Divalent chain group-
L-6: -Divalent chain group-O-Divalent cyclic group-Divalent chain group-CO-O-
L-7: -Divalent chain group-O-Divalent cyclic group-Divalent chain group-O-CO-
L-8: -Divalent chain group -O-CO-Divalent cyclic group-
L-9: -Divalent chain group -O-CO-Divalent cyclic group -CO-O-
L-10: -Divalent chain group -O-CO-Divalent cyclic group -O-CO-
L-11: a divalent chain group —O—CO—a divalent cyclic group —CO—NR ₇ —.
L-12: -Divalent chain group-O-CO-Divalent cyclic group-Divalent chain group-
L-13: -Divalent chain group-O-CO-Divalent cyclic group-Divalent chain group-CO-O-
L-14: -Divalent chain group-O-CO-Divalent cyclic group-Divalent chain group-O-CO-
L-15: -Divalent chain group-CO-O-Divalent cyclic group-
L-16: -Divalent chain group -CO-O-Divalent cyclic group -CO-O-
L-17: -Divalent chain group -CO-O-Divalent cyclic group -O-CO-
L-18: - divalent chain group -CO-O- divalent cyclic group -CO-NR ₇ -
L-19: -Divalent chain group-CO-O-Divalent cyclic group-Divalent chain group-
L-20: -Divalent chain group-CO-O-Divalent cyclic group-Divalent chain group-CO-O-
L-21: -Divalent chain group -CO-O-Divalent cyclic group -Divalent chain group -O-CO-
L-22: -Divalent chain group -O-CO-O-Divalent cyclic group-
L-23: -Divalent chain group -O-CO-O-Divalent cyclic group -CO-O-
L-24: -Divalent chain group -O-CO-O-Divalent cyclic group -O-CO-
L-25: - divalent chain group -O-CO-O-divalent cyclic group -CO-NR ₇ -
L-26: -Divalent chain group-O-CO-O-Divalent cyclic group-Divalent chain group-
L-27: -Divalent chain group -O-CO-O-Divalent cyclic group -Divalent chain group -CO-O-
L-28: -Divalent chain group-O-CO-O-Divalent cyclic group-Divalent chain group-O-CO-
L-29: -Divalent chain group-
L-30: -Divalent chain group -O-
L-31: -Divalent chain group -CO-O-
L-32: -Divalent chain group -O-CO-
L-33: - divalent chain group -CO-NR ₇ -
L-34: -Divalent chain group-O-Divalent chain group-
L-35: -Divalent chain group -O-Divalent chain group -O-
L-36: -Divalent chain group -O-Divalent chain group -CO-O-
L-37: -Divalent chain group -O-Divalent chain group -O-CO-

  Among the above, L-2, L-3, L-9, L-10, L-16, L-17, L-23, L-24, L-30, L-31, L-32, L- 35, L-36, and L-37 are preferred.

R ₁ , R ₂ and R ₃ are most preferably each independently represented by the following general formula (V).

In general formula (V), * represents the position bonded to the 5-membered ring in general formula (I).
R ₄ is independently a halogen atom (preferably a fluorine atom, a chlorine atom, a bromine atom or an iodine atom), an alkyl group having 1 to 8 carbon atoms, an alkyloxy group having 1 to 8 carbon atoms, or 2 to 2 carbon atoms. 8 represents an acyl group, an acyloxy group having 2 to 8 carbon atoms, an alkoxycarbonyl group having 2 to 8 carbon atoms, a nitro group, and a cyano group. Preferably, a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkyloxy group having 1 to 3 carbon atoms, an acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, and the number of carbon atoms 2 to 4 alkoxycarbonyl groups and a cyano group.
l represents an integer of 0 to 4, preferably 0 or 1, and most preferably 0. When l is 2 or more, a plurality of groups represented by R ₄ may be different from each other.
L ₆ represents **-O-, **-CO-O-, **-O-CO-, **-O-CO-O-, or **-CH _2- , and ** is general It represents the position bonded to the benzene ring in formula (V).
R ₅ represents a hydrogen atom, a methyl group, an ethyl group or a propyl group, more preferably a hydrogen atom or a methyl group, and most preferably a hydrogen atom.
m represents an integer of 2 to 16, preferably an integer of 2 to 12.
R ₆ represents a hydrogen atom or a methyl group, preferably a hydrogen atom.

In the present invention, among the compounds represented by the general formula (I), R ₁ , R ₂ and R ₃ are each independently represented by the general formula (I) represented by the general formula (V). Are preferred.
As the liquid crystal phase expressed by the compound represented by formula (I) and the liquid crystal composition containing the compound, a columnar phase or a discotic nematic phase is preferable, and a discotic nematic phase is particularly preferable. The liquid crystal phase is preferably expressed in the range of 30 to 300 ° C, and more preferably expressed in the range of 50 to 250 ° C.

  Even if the compound represented by the general formula (I) does not show a discotic liquid crystal phase, it can be used by mixing a compound showing a discotic liquid crystal phase.

  Specific examples of the compound represented by formula (I) are shown below, but the present invention is not limited to these.

[Liquid crystal composition expressing a biaxial nematic phase containing a liquid crystal compound expressing a rod-like liquid crystal phase and a liquid crystal compound expressing a discotic liquid crystal phase]
The liquid crystal composition of the present invention including a liquid crystal compound that exhibits a rod-like liquid crystal phase and a liquid crystal compound that exhibits a discotic liquid crystal phase preferably exhibits a biaxial nematic phase within a range of 20 ° C to 300 ° C. More preferably, it is 40 degreeC-280 degreeC, Most preferably, it is 60 degreeC-250 degreeC. Here, the expression of the liquid crystal phase within the range of 20 ° C. to 300 ° C. means that the liquid crystal temperature range spans 20 ° C. (specifically, for example, 10 ° C. to 22 ° C.) or 300 ° C. (specifically, For example, 298 degreeC-310 degreeC) is also included. The same applies to 40 ° C to 280 ° C and 60 ° C to 250 ° C.

The liquid crystal composition of the present invention comprising a liquid crystal compound that exhibits a rod-like liquid crystal phase and a liquid crystal compound that exhibits a discotic liquid crystal phase, and a liquid crystal compound that exhibits a rod-like liquid crystal phase and a discotic for producing a biaxial nematic phase The mixing ratio of the liquid crystal compound that expresses the liquid crystal phase varies depending on the molecular structure and molecular weight, and thus cannot be clearly defined, but the mass ratio of (liquid crystal compound that expresses a rod-like liquid crystal phase) / (liquid crystal compound that expresses a discotic liquid crystal phase) ) = 10 to 0.02, preferably 5 to 0.05, and most preferably 2 to 0.1.
The biaxial nematic phase often appears at a lower temperature than the uniaxial liquid crystal phase. For example, a uniaxial nematic phase (nematic phase or discotic nematic phase) is often lowered to a biaxial nematic phase by lowering the temperature. In many cases, when the content ratio of a liquid crystal compound that expresses a rod-like liquid crystal phase increases slightly with a certain mixing ratio ((liquid crystal compound that expresses a rod-like liquid crystal phase) / (liquid crystal compound that expresses a discotic liquid crystal phase)). When the temperature is lowered, a transition from the nematic phase to the biaxial nematic phase occurs. Further, when the content of the liquid crystal compound expressing the discotic liquid crystal phase is slightly increased, a transition from the discotic nematic phase to the biaxial nematic phase occurs.

In the liquid crystal composition of the present invention comprising a liquid crystal compound that exhibits a rod-like liquid crystal phase and a liquid crystal compound that exhibits a discotic liquid crystal phase, when there is a uniaxial nematic phase on the high temperature side of the biaxial nematic phase, It is possible to control the value of (nx−nz) / (nx−ny) of the liquid crystal phase.
For example, when the temperature is lowered from the nematic phase ((nx−nz) / (nx−ny) = 1.0), the value of (nx−nz) / (nx−ny) does not change suddenly, It tends to rise gradually according to the situation. Therefore, the (nx−nz) / (nx−ny) value can be controlled by selecting the temperature at which the orientation is fixed such as polymerization by UV irradiation. When the nematic phase is changed to the biaxial nematic phase, the control range width of the (nx-nz) / (nx-ny) value is a liquid crystal compound that exhibits a rod-like liquid crystal phase and a liquid crystal that exhibits a discotic liquid crystal phase. Since it varies depending on the molecular structure of the compound, etc., it cannot be defined unconditionally, but a range closer to 1.0 is easily controlled. Specifically, 1.0 <(nx−nz) / (nx−ny) <10 is easy to control.
Also, when the transition from the discotic nematic phase to the biaxial nematic phase is possible, the (nx−nz) / (nx−ny) value can be controlled as in the case of the transition from the nematic phase. In this case, since the (nx−nz) / (nx−ny) value of the discotic nematic phase is infinite (nx = ny), the control range width is easily controlled in a range closer to infinity. Specifically, 1.2 <(nx−nz) / (nx−ny) <∞ is easy to control.

  The optically anisotropic layer is composed of a liquid crystalline molecule or the following polymerizable initiator or any additive (eg, plasticizer, monomer, surfactant, cellulose ester, 1,3,5-triazine compound, optically active compound, It is formed by applying a liquid crystal composition (coating liquid) containing an air interface alignment controller and a repellency inhibitor onto the alignment film. As the solvent used for preparing the liquid crystal composition, 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 liquid crystal composition can be applied by a known method (eg, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

The polymerization reaction of liquid crystalline molecules 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 (for example, those described in US Pat. Nos. 2,367,661 and 2,367,670) and acyloin ethers (for example, those described in US Pat. No. 2,448,828). ), Α-hydrocarbon substituted aromatic acyloin compounds (for example, those described in US Pat. No. 2,722,512), polynuclear quinone compounds (for example, those described in US Pat. Nos. 3,046,127 and 2,951,758) , Combinations of triarylimidazole dimers and p-aminophenyl ketone (for example, those described in US Pat. No. 3,549,367), acridine and phenazine compounds (for example, JP-A-60-105667, US Pat. No. 4,239,850) Oxadiazole compounds) (For example, described in US Pat. No. 4,212,970). The amount of the photopolymerization initiator used is preferably 0.01 to 20% by weight, more preferably 0.5 to 5% by weight, based on the solid content of the coating solution. It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules. Irradiation energy is preferably 20~50J / 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 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm. Furthermore, when providing a some optically anisotropic layer, it is preferable that it is the said thickness each independently.

[Air interface alignment control agent]
The liquid crystal composition is aligned at the air interface at the tilt angle of the air interface. The tilt angle varies depending on the type of liquid crystal compound and the type of additives contained in the liquid crystal composition, and therefore, it is necessary to arbitrarily control the tilt angle of the air interface according to the purpose.

  For controlling the tilt angle, for example, an external field such as an electric field or a magnetic field or an additive can be used, and an additive is preferably used. Examples of such an additive include a substituted or unsubstituted aliphatic group having 6 to 40 carbon atoms, or a substituted or unsubstituted aliphatic substituted oligosiloxanoxy group having 6 to 40 carbon atoms in the molecule. A compound having one or more is preferable, and a compound having two or more in the molecule is more preferable. For example, a hydrophobic excluded volume effect compound described in JP-A No. 2002-20363 can be used as the air interface alignment control agent.

  The addition amount of the alignment control additive on the air interface side is preferably 0.001% by mass to 20% by mass, more preferably 0.01% by mass to 10% by mass, with respect to the liquid crystal composition of the present invention. 0.1 mass%-5 mass% are the most preferable.

[Anti-repellent agent]
As a material for adding to the liquid crystal composition of the present invention and preventing repelling at the time of application of the composition, generally, a polymer compound can be suitably used.
The polymer to be used is not particularly limited as long as the tilt angle change and orientation of the liquid crystal composition of the present invention are not significantly inhibited.
Examples of the polymer are described in JP-A-8-95030, and particularly preferred specific polymer examples include cellulose esters. Examples of cellulose esters include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate.
In order not to inhibit the alignment of the liquid crystal composition of the present invention, the amount of the polymer used for the purpose of preventing repellency is generally in the range of 0.1 to 10% by mass with respect to the liquid crystal composition of the present invention. More preferably, it is in the range of 1 to 8% by mass, and more preferably in the range of 0.1 to 5% by mass.

[Transparent support]
As a transparent support for the optical compensation film, a glass plate or a polymer film, preferably a polymer film is used. That the support is transparent means that the light transmittance is 80% or more. When emphasizing the relaxation of gradation inversion, it is more preferable to use an optically isotropic polymer film as the transparent support. The optical isotropy specifically means that the in-plane retardation value (Re value) is less than 10 nm, and preferably less than 5 nm. In the optically isotropic transparent support, the thickness direction retardation (Rth) is preferably less than 10 nm, more preferably less than 5 nm. The in-plane retardation (Re) and the thickness direction retardation (Rth) of the transparent support are respectively defined by the following formulas.
Re = (nx−ny) × d
Rth = [{(nx + ny) / 2} -nz] × d
In the formula, nx and ny are in-plane refractive indexes of the transparent support, nz is the refractive index in the thickness direction of the transparent support, and d is the thickness of the transparent support.

  When emphasizing the expansion of the viewing angle in display, it may be effective to use an optically anisotropic polymer film as the transparent support. That is, the liquid crystal cell is optically compensated by adding the optical anisotropy of the transparent support to the optical anisotropy of the optically anisotropic layer. In such a case, the transparent support preferably has optical uniaxiality or optical biaxiality. In the case of an optically uniaxial support, it is optically positive, that is, optically negative, that is, refractive in the optical axis direction, even if the refractive index in the optical axis direction is larger than the refractive index in the direction perpendicular to the optical axis. The refractive index may be smaller than the refractive index in the direction perpendicular to the optical axis. In the case of an optical biaxial support, the refractive indices nx, ny and nz in the above formula are all different values (nx ≠ ny ≠ nz). The in-plane retardation value (Re value) of the optically anisotropic transparent support is preferably 10 to 100 nm, more preferably 10 to 50 nm, and most preferably 10 to 30 nm. The retardation value (Rth value) in the thickness direction of the optically anisotropic transparent support is preferably 10 to 200 nm, more preferably 10 to 100 nm, and still more preferably 10 to 50 nm.

  The material for forming the transparent support can be determined depending on, for example, whether it is an optical isotropic support or an optical anisotropic support. In the case of an optically isotropic support, glass or cellulose ester is generally used. In the case of an optically anisotropic support, a synthetic polymer (eg, polycarbonate, polysulfone, polyethersulfone, polyacrylate, polymethacrylate, norbornene resin) is generally used. However, optical properties may be reduced by (1) using a retardation increasing agent, (2) reducing the acetylation degree of cellulose acetate, or (3) producing a film by the cooling dissolution method described in the specification of European Patent 0911656A2. An isotropic (high retardation) cellulose ester film can also be produced. The transparent support made of a polymer film is preferably formed by a solvent cast method.

  In order to obtain an optically anisotropic transparent support, the polymer film is preferably subjected to a stretching treatment. When an optical uniaxial support is produced, a normal uniaxial stretching process or biaxial stretching process may be performed. When producing an optical biaxial support, it is preferable to perform an unbalanced biaxial stretching process. In the unbalanced biaxial stretching, the polymer film is stretched in a certain direction at a certain ratio, for example, 3 to 100%, preferably 5 to 30%, and further in the direction perpendicular thereto, for example, 6 to 200%. The film is preferably stretched to 10 to 90%. The bi-directional stretching process may be performed one by one or simultaneously. The stretching direction (in the case of unbalanced biaxial stretching, the direction in which the stretching ratio is high) and the in-plane slow axis of the stretched film are preferably substantially the same direction. Here, the substantially same direction means that the angle between the stretching direction and the slow axis is preferably less than 10 degrees, more preferably less than 5 degrees, and most preferably less than 3 degrees. .

[Alignment film]
The alignment film is an organic compound (eg, ω-tricosanoic acid) formed by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroove, or Langmuir-Blodgett method (LB film). , Dioctadecylmethylammonium chloride, methyl stearylate). 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 preferable. The rubbing treatment 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 is determined according to the alignment (particularly the average tilt angle) of the liquid crystal molecules. In order to align liquid crystal molecules relatively horizontally (average tilt angle: 0 to 50 degrees), a polymer that does not decrease the surface energy of the alignment film (for example, a general alignment film polymer) is used. In order to align liquid crystal molecules relatively perpendicularly (average tilt angle: 50 to 90 degrees), a polymer that reduces the surface energy of the alignment film is used. In order to reduce the surface energy of the alignment film, it is preferable to introduce a hydrocarbon group having 10 to 100 carbon atoms into the side chain of the polymer.

  Specific polymer types are described in literature on optical compensation films using liquid crystalline molecules corresponding to various liquid crystal display modes. The thickness of the alignment film is preferably 0.01 to 5 μm, more preferably 0.05 to 1 μm. In addition, after aligning the liquid crystalline molecules of the optically anisotropic layer using the alignment film, the optically anisotropic layer may be transferred onto the transparent support. The liquid crystalline molecules fixed in the alignment state can maintain the alignment state even without the alignment film. Further, in the case of orientation with an average tilt angle of less than 5 degrees, there is no need for rubbing treatment and no orientation film is required. However, for the purpose of improving the adhesion between the liquid crystalline molecules and the transparent support, an alignment film that forms a chemical bond with the liquid crystalline molecules at the interface (for example, those described in JP-A-9-152509) is used. Also good. When an alignment film is used for the purpose of improving adhesion, rubbing treatment need not be performed. When two types of optically anisotropic layers are provided on the same side of the transparent support, the optically anisotropic layer formed on the transparent support may function as an alignment film for the optically anisotropic layer provided thereon. Is possible.

[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 polarization axis of the polarizing film corresponds to a direction perpendicular to the stretching direction of the film. The polarization axis in the plane of the polarizing film is preferably arranged so as to be substantially orthogonal to the average direction of the lines obtained by projecting the major axis direction of the rod-like liquid crystalline molecules onto the transparent support surface.

[Transparent protective film]
A transparent polymer film is used as the transparent protective film. That the protective film is transparent means that the light transmittance is 80% or more. As the transparent protective film, generally a cellulose ester film, preferably a triacetyl cellulose film is used. The cellulose ester film is preferably formed by a solvent cast method. The thickness of the transparent protective film is preferably 20 to 500 μm, and more preferably 50 to 200 μm.

[Liquid Crystal Display]
The present invention is particularly effective in a TN mode liquid crystal display device. TN mode liquid crystal cells are used in the most widespread color TFT liquid crystal displays, and are described in various literatures, and can be widely used in these.

  In the TN mode liquid crystal display device, in a non-driving state in which no driving voltage is applied to the electrodes, the liquid crystalline molecules in the liquid crystal cell are aligned substantially parallel to the substrate surface, and the alignment direction is twisted 90 degrees between the upper and lower substrates. ing. As the applied voltage is increased, the liquid crystalline molecules gradually stand in the direction perpendicular to the substrate surface while eliminating the twist.

  The product Δn · d of the thickness d (μm) of the liquid crystal layer and the refractive index anisotropy Δn is preferably 0.2 to 0.5 μm. The twist angle (twist angle) of the liquid crystal layer is an optimum value around 90 degrees (85 to 95 degrees). In these ranges, since the white display luminance is high and the black display luminance is low, a bright and high-contrast display device can be obtained. Note that these optimum values are values of the transmission mode, and in the reflection mode, the optical path in the liquid crystal cell is doubled. Therefore, the value of the optimum Δn · d is about the above half value. The optimum twist angle is 30 to 70 degrees.

  The liquid crystal display device of the present invention is not limited to the configuration shown in FIGS. 2 and 3 and may include other members. For example, a color filter may be disposed between the liquid crystal cell and the polarizing film. In the case of use as a transmission type, a cold cathode or a hot cathode fluorescent tube, or a backlight using a light emitting diode, a field emission element, or an electroluminescent element as a light source can be disposed. In addition, the liquid crystal display device of the present invention may be of a reflective type. In such a case, only one polarizing plate may be disposed on the observation side, and reflected on the back surface of the liquid crystal cell or the inner surface of the lower substrate of the liquid crystal cell. Install the membrane. Of course, it is also possible to provide a front light using the light source on the liquid crystal cell observation side. Furthermore, the liquid crystal display device of the present invention may be a transflective type in which a reflective portion and a transmissive portion are provided in one pixel of the display device in order to achieve both transmission and reflection modes.

The liquid crystal display device of the present invention includes, for example, an image direct view type, an image projection type, and a light modulation type.
The present invention is particularly effective when applied to an active matrix liquid crystal display device using three-terminal or two-terminal semiconductor elements such as TFT and MIM. Of course, an embodiment applied to a passive matrix liquid crystal display device represented by the STN type is also effective.

  The operation of the liquid crystal display device shown in FIG. 2 will be described using the TN mode as an example. In this embodiment, an example in which active driving is performed using a nematic liquid crystal having positive dielectric anisotropy will be described. In the TN mode, a liquid crystal having a positive dielectric anisotropy between the upper and lower substrates 5a and 5b, a refractive index anisotropy Δn = 0.0854 (589 nm, 20 degrees C), and a dielectric anisotropy Δε = + 8.5. Is rubbed to produce a liquid crystal cell. The alignment control of the liquid crystal layer is controlled by an alignment film and rubbing. A director indicating the alignment direction of the liquid crystal molecules, that is, a so-called tilt angle is preferably about 3 degrees. The rubbing direction is applied in a direction perpendicular to the upper and lower substrates, and the tilt angle can be controlled by the strength and the number of rubbing times. The alignment film is formed by applying and baking a polyimide film. The magnitude of the twist angle of the liquid crystal layer is determined by the crossing angle of the upper and lower substrates in the rubbing direction and the chiral agent added to the liquid crystal material. Here, a chiral agent having a pitch of about 60 μm is added so that the twist angle is 90 degrees. The thickness d of the liquid crystal layer is set to 5 μm.

  Further, the liquid crystal material LC is not particularly limited as long as it is a nematic liquid crystal. A larger value of the dielectric anisotropy Δε is preferable because the drive voltage can be reduced. When the refractive index anisotropy Δn is reduced, the thickness (gap) of the liquid crystal layer can be increased, and gap variation can be effectively reduced. Further, when Δn is increased, the cell gap can be reduced, and high-speed response can be achieved more effectively.

  The polarizing axis of the upper polarizing film 2b and the polarizing axis of the lower polarizing film 2a are stacked substantially orthogonally, and the polarizing axis of the upper polarizing film 2b of the liquid crystal cell and the rubbing direction of the upper substrate 5b are approximately parallel, and the lower polarizing film 2a. The polarizing axis and the rubbing direction of the lower substrate 5a are laminated so as to be approximately parallel to each other. A transparent electrode (not shown) is formed inside each alignment film of the upper substrate 5b and the lower substrate 5a, but in a non-driving state in which a driving voltage is not applied to the electrodes, the liquid crystalline molecules in the liquid crystal cell are the substrates. As a result, the polarization state of light passing through the liquid crystal panel is propagated along the twisted structure of the liquid crystalline molecules, and the polarization plane is rotated 90 degrees and emitted. That is, the liquid crystal display device realizes white display in the non-driven state. In contrast, in the driving state, the liquid crystalline molecules are aligned in a direction that forms an angle with respect to the substrate surface, and the light that has passed through the lower polarizing film 2a passes through the liquid crystal layer 6 while maintaining the polarization state. Are blocked by the polarizing film 2b. In other words, an ideal black display can be obtained in the driving state in the liquid crystal display device.

  It is also possible to reduce the driving angle of the liquid crystal display and reduce the angle at which the liquid crystal molecules stand in the TN mode liquid crystal cell.

[Synthesis Example 1: Synthesis of Liquid Crystal Compound Example D-8 Expressing Discotic Liquid Crystal Phase and Having Polymerizable Group]
D-8 was synthesized according to the following scheme.

5.0 g of (D-3) synthesized according to the method described in the literature (Kim, Bong Gi et al., Molecular Crystals and Liquid Crystals, 2001, 370, 391) was dissolved in 100 ml of CH ₂ Cl _2. 75 ml of boron bromide (1.0 M CH ₂ Cl ₂ solution) was added. After stirring at 40 ° C. for 12 hours, water was added to the reaction solution, and the precipitated crystals were collected by filtration. By drying this crystal, 3.0 g of a trihydroxy compound was obtained.
After dissolving 5 g of 3-bromo-1-propanol in 20 ml of dimethylacetamide, 3.8 ml of acryloyl chloride was added dropwise at a reaction temperature of 40 ° C. or lower. After stirring for 1 hour, 200 ml of water was added and the mixture was extracted with ethyl acetate / hexane. After liquid separation, the organic layer was distilled off, 0.5 g of the above trihydroxy compound, 2.0 g of potassium carbonate and dimethylformamide were added, and the mixture was stirred at 100 ° C. for 10 hours.
Water was added to the reaction solution, extracted with CH ₂ Cl ₂ , the organic layer was concentrated and purified using column chromatography to obtain 0.8 g of white crystals of D-8.

¹ H-NMR (solvent: CDCl ₃ , standard: tetramethylsilane) δ (ppm):
2.15-2.30 (6H, m)
4.18 (6H, t)
4.43 (6H, t)
5.86 (3H, d)
6.16 (3H, dd)
6.45 (3H, d)
7.08 (6H, d)
8.16 (6H, d)
9.02 (3H, s)

  The phase transition temperature of the obtained D-8 was measured by texture observation with a polarizing microscope. As a result, the temperature was increased and the crystal phase was changed to a discotic nematic phase around 125 ° C. Transition to phase. That is, it was found that D-8 exhibits a discotic nematic phase between 125 ° C. and 149 ° C.

[Synthesis Example 2: Synthesis of plate-like liquid crystal compound example TO-3 that exhibits a rod-like liquid crystal phase]
TO-3 was synthesized according to the following scheme.

(Synthesis of m-4A)
25.0 g of bromohydroquinone was dissolved in 70 ml of pyridine (Py), and 37 ml of acetic anhydride (Ac ₂ O) was added dropwise at a reaction temperature of 50 ° C. or lower. After stirring for 3 hours, water was added to the reaction mixture, and the mixture was extracted with ethyl acetate. The obtained organic layer was washed with saturated aqueous sodium hydrogen carbonate, diluted hydrochloric acid, water and saturated brine, and the solvent was evaporated under reduced pressure. Crystallization with hexane gave 32.2 g of m-4A crystals.

(Synthesis of m-4B)
32.2 g of m-4A, 17.4 g of trimethylsilyl (TMS) acetylene, 0.5 g of triphenylphosphine, 0.25 g of bis (triphenylphosphine) palladium (II) dichloride and 80 mg of copper (I) iodide are dissolved in 200 ml of triethylamine. And refluxed for 10 hours under a nitrogen atmosphere. After cooling, the precipitated triethylamine hydrochloride was filtered off, and the organic layer was distilled off under reduced pressure. The obtained residue was purified by column chromatography to obtain 32.0 g of m-4B crystals.

(Synthesis of m-4C)
32.0 g of m-4B was dissolved in 200 ml of tetrahydrofuran, 120 ml of a tetrahydrofuran solution (1.0 M solution) of tetrabutylammonium fluoride (TBAF) was added, and the mixture was stirred at room temperature for 30 minutes. Water was added to the reaction mixture, and the mixture was extracted with ethyl acetate and washed with saturated brine. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain 20.5 g of m-4C crystals.

(Synthesis of TO-3A)
20.4 g of 2,3-dicyanohydroquinone was dissolved in 150 ml of t-butanol, and 22.6 g of NBS (N-bromosuccinimide) was added, followed by stirring at room temperature for 4 hours. The reaction mixture was added to 1 L of water, and the precipitated crystals were filtered. Concentrated hydrochloric acid was added to the filtrate, and the mixture was extracted with ethyl acetate. The organic layer was concentrated under reduced pressure and purified by column chromatography to obtain 8.5 g of TO-3A.

(Synthesis of TO-3B)
8.0 g of TO-3A was dissolved in 50 ml of tetrahydrofuran, and 25 ml of pyridine (Py) and 20 ml of acetic anhydride (Ac ₂ O) were added dropwise. After stirring for 12 hours, the reaction solution was added to 1 L of water, and the precipitated crystals were separated by filtration and dried. The obtained crystals were purified by column chromatography to obtain 9.7 g of TO-3B.

(Synthesis of TO-3C)
3.0 g of TO-3B, 2.43 g of m-4c obtained according to the above, 60 mg of triphenylphosphine, 30 mg of bis (triphenylphosphine) palladium (II) dichloride and 10 mg of copper (I) iodide were dissolved in 100 ml of triethylamine. The mixture was heated at 60 ° C. for 5 hours in a nitrogen atmosphere. After cooling, methanol was added to the reaction solution, and the precipitated crystals were separated by filtration and dried. The obtained crystals were purified by column chromatography to obtain 1.7 g of TO-3C.

(Synthesis of TO-3D)
1.7 g of TO-3C was dissolved in 40 ml of tetrahydrofuran, and 5 ml of sodium methoxide (28% methanol solution) and 20 ml of methanol were added under nitrogen bubbling. After stirring at room temperature for 30 minutes, dilute hydrochloric acid was added, and the mixture was extracted with ethyl acetate. The obtained organic layer was distilled off under reduced pressure to obtain 1.0 g of TO-3D.

(Synthesis of TO-3)
0.43 g of methanesulfonyl chloride was dissolved in 10 ml of tetrahydrofuran and cooled to 0 ° C. To this solution was added dropwise a solution of 1.0 g of 4- (4-acryloyloxybutyloxy) benzoic acid and 0.51 g of diisopropylethylamine in 10 ml of tetrahydrofuran. After stirring at 0 ° C. for 1 hour, 0.51 g of diisopropylethylamine and 0.02 g of 4-dimethylaminopyridine were added, and then a solution of 0.14 g of TO-3D in 10 ml of tetrahydrofuran was added. After stirring at room temperature for 12 hours, water was added to the reaction mixture, and the mixture was extracted with CH ₂ Cl ₂ . After concentration under reduced pressure, the residue was purified using column chromatography to obtain 0.32 g of TO-3 white crystals. The NMR spectrum of the obtained TO-3 is as follows.

¹ H-NMR (solvent: CDCl ₃ , standard: tetramethylsilane) δ (ppm):
1.70-1.90 (8H, m)
1.90-2.00 (8H, m)
3.90-4.00 (4H, m)
4.08-4.18 (4H, m)
4.19-4.30 (8H, m)
5.80-5.90 (4H, m)
6.07-6.20 (4H, m)
6.36-6.48 (4H, m)
6.90-7.05 (9H, m)
7.25 (1H, dd)
7.32 (1H, d)
7.47 (1H, d)
8.06-8.20 (8H, m)

  When the phase transition temperature of the obtained TO-3 was measured by texture observation with a polarizing microscope, the temperature was raised and the crystal phase was changed to a nematic liquid crystal phase at around 122 ° C, and when it exceeded 195 ° C, it became an isotropic liquid phase. It has changed. That is, TO-3 exhibits a nematic liquid crystal phase between 122 ° C. and 195 ° C.

Example 1
[Confirmation of biaxial nematic phase]
After dissolving 0.225 g of (D-8) and 0.100 g of (TO-3) in CH ₂ Cl ₂ , the solvent was evaporated to obtain (BAmix-1). (BAmix-1) was revealed by observation with a polarizing microscope to develop a nematic phase at 100 ° C. or lower when the temperature dropped from 150 ° C.
Next, this (BAmix-1) is injected into a horizontal alignment cell (manufactured by EHC; KSRP-05 / A107M1NSS (ZZ)) having a cell gap of 5 μm at 110 ° C., and cooled to 100 ° C., the nematic phase is obtained. It shifted to homeotropic orientation and became a dark field. When the temperature was further lowered to 80 ° C., liquid crystal transition occurred and the biaxial nematic phase was transformed. It was maintained at 80 ° C. for 3 minutes, the angle dependency of retardation was measured, and (nx−nz) / (nx−ny) was determined to be 4.0.

Example 2
[Production of optical compensation film]
(Preparation of undercoat layer / transparent support)
A triacetyl cellulose film (thickness: 100 μm) (manufacturer: Fuji Photo Film Co., Ltd., product number: Fujitac TD-80U) was used as a transparent support. The Re of the transparent support was 1 nm and Rth was 48 nm. Gelatin having a thickness of 0.1 μm was coated on both surfaces of the transparent support to form first and second undercoat layers.

(Preparation of the first alignment film)
On the first undercoat layer, an aqueous solution of the following modified polyvinyl alcohol 2% by weight and glutaraldehyde 0.1% by weight was applied, dried with hot air at 80 ° C., and then subjected to a rubbing treatment to give a first orientation. A film was formed.

(Formation of optically anisotropic layer)
On the rubbed alignment film prepared above, an optically anisotropic layer coating solution having the following composition was applied using a spin coater.

(Optically anisotropic layer coating solution)
-69.2 parts by mass of the liquid crystal compound D-8-30.8 parts by mass of the liquid crystal compound TO-3-0.2 parts by mass of the following air interface alignment control agent-1 part by mass of the polymerizable optically active compound・ 700 parts by mass of chloroform

  The support coated with the optically anisotropic layer is placed in a thermostatic bath at 130 ° C., heated to 120 ° C., then cooled to 95 ° C., and held at that temperature for 2 minutes. Next, it is placed in a constant temperature bath of 80 ° C. with an oxygen concentration of 2%, and after 5 minutes, 600 mJ ultraviolet rays are irradiated to fix the orientation state of the optically anisotropic layer. Allow to cool to room temperature to produce an optical compensation film. The thickness of the optically anisotropic layer is 1.2 μm. When the angle dependency of the retardation of the obtained optical compensation film was measured, the ny direction and the nz direction changed in the film thickness direction. As a result of measuring the twist angle, the twist angle was 1 degree.

(Production of liquid crystal display device)
A polyimide alignment film was provided on a glass substrate on which an ITO transparent electrode was provided, and a rubbing treatment was performed. Two substrates were stacked with the alignment film facing each other through a spacer. The two substrates were arranged so that the rubbing directions of the alignment films were orthogonal. A rod-like liquid crystal molecule (ZL4792, manufactured by Merck & Co., Inc.) was injected into the gap between the substrates to form a rod-like liquid crystal layer. The Δnd of the rod-like liquid crystal molecule was 420 nm.

Two optical compensation films prepared in Example 2 are attached to both sides of the TN liquid crystal cell manufactured as described above so that the optically anisotropic layer faces the substrate of the liquid crystal cell. Further, two polarizing plates are attached to the outside of these to produce a liquid crystal display device. The rubbing direction of the alignment film of the optical compensation sheet and the rubbing direction of the alignment film of the liquid crystal cell adjacent thereto are arranged to be antiparallel. In addition, the absorption axis of the polarizing plate and the rubbing direction of the liquid crystal cell are arranged in parallel.
As a result, it can be confirmed that the viewing angle can be widened and coloring is not seen.

Comparative Example 1
A similar liquid crystal display device was prepared except that the polymerizable optically active compound of Example 2 was omitted. As a result of measuring the twist angle, the twist angle was 0.0 degree.

Comparative Example 2
A liquid crystal display device was prepared by removing two optical compensation films from the liquid crystal display device of Example 2.

  As for the optical characteristics of the liquid crystal display device produced as described above, a voltage was applied using a function generator (FG-281: manufactured by Kenwood TMK), and a variable angle goniometer (GSP-3B: Murakami Color Research Laboratory) was used for measurement. As for the voltage, luminance-viewing angle characteristics and contrast-viewing angle characteristics were measured in 8 gradations in which the front black display (L0) and white display (L7) luminances were equally spaced. Table 1 shows the viewing angle range in which the angles L1 and L2 intersect on the lower side in the vertical direction (the angle at which gradation inversion occurs) and the contrast ratio 20: 1 are obtained.

  The present invention is excellent in both a vertical viewing angle, a left and right viewing angle, a downward gradation inversion angle, no retardation film, and a simple biaxial hybrid alignment film.

It is a schematic diagram which shows an inclination angle and a twist angle. It is a schematic diagram which shows the basic composition of a transmissive liquid crystal display device. It is a schematic diagram which shows the basic composition of a reflection type liquid crystal display device.

Explanation of symbols

BL backlight 1a, 1b transparent protective film 2a, 2b polarizing film 3a, 3b optically anisotropic layer 4a, 4b transparent support 5a lower substrate 5b of liquid crystal cell upper substrate 6 of liquid crystal cell rod-like liquid crystal molecule 7 reflector

Claims (8)

  An optical compensation film having an optically anisotropic layer containing a liquid crystal composition exhibiting a biaxial nematic phase in a state of giving a hybrid alignment and a twist alignment.   An optical compensation film having an optically anisotropic layer formed from a liquid crystal composition that exhibits a biaxial nematic phase, wherein the optically anisotropic layer has a biaxial nematic phase imparting a twisted orientation to a hybrid orientation. An optical compensation film formed by being fixed.   When the refractive index in the triaxial direction of the liquid crystal composition expressing the biaxial nematic phase is nx, ny, and nz in descending order, the angle formed by nx and the plane direction of the film hardly changes in the thickness direction, and 3. The optical compensation film according to claim 1, wherein an angle formed by nz and the surface direction of the film changes in the thickness direction.   The optical compensation film according to claim 1, wherein the twist angle is less than 10 degrees.   The optical compensation film according to any one of claims 1 to 4, wherein the liquid crystal composition that exhibits a biaxial nematic phase includes a liquid crystal compound that exhibits a rod-like liquid crystal phase and a liquid crystal compound that exhibits a discotic liquid crystal phase. .   A liquid crystal composition containing an optically active compound and a liquid crystal compound expressing a biaxial nematic phase is laminated on a support coated with an alignment film, and then the biaxial nematic phase is expressed and immobilized. 6. The optical compensation film according to any one of 5 above.   An elliptically polarizing plate, wherein the optical compensation film and polarizing film according to any one of claims 1 to 6 are laminated on a transparent support.   The liquid crystal display device using the optical compensation film of any one of Claims 1-6, or the elliptically polarizing plate of Claim 7.

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