JP5353039B2 - Liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display excellent in (front) contrast and image quality. <P>SOLUTION: This liquid crystal display satisfies Expression (I): nx&ge;ny&gt;nz where nx and ny represent refractive indexes in x- and y-directions orthogonal each other in an in-plane direction in a phase difference layer of a phase difference body, and nz represents a z-directional refractive index in a thickness direction in the phase difference layer, and satisfies Expression (II): Re(Cell)&gt;Re(C) where Re(Cell) is defined as an in-plane phase difference of a liquid crystal cell, and Re(C) is defined as an in-plane phase difference of the phase difference body. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a liquid crystal display device.

  In the liquid crystal display device, in particular, the liquid crystal unit includes an incident-side polarizing plate, an outgoing-side polarizing plate, and a liquid crystal cell. The liquid crystal display device employs various driving methods. For example, in a liquid crystal display device, a VA (Vertical Alignment) method in which a liquid crystal cell is sealed with a nematic liquid crystal having negative dielectric anisotropy can be used. In the VA method, when the linearly polarized light that has passed through the polarizing plate on the incident side passes through the non-driven cell portion of the liquid crystal cell, it is transmitted without being phase-shifted and blocked by the polarizing plate on the outgoing side. . On the other hand, when passing through the portion of the liquid crystal cell in the driven state, the linearly polarized light is phase-shifted, and an amount of light corresponding to the amount of this phase shift is transmitted through the exit-side polarizing plate and emitted. The Accordingly, a desired image can be displayed on the exit side polarizing plate side by appropriately controlling the driving voltage of the liquid crystal cell for each cell. The VA system is attracting attention as being capable of expanding the viewing angle as compared to the TN system.

  Here, considering the case where linearly polarized light is transmitted through the non-driven cell portion of the VA liquid crystal cell, the liquid crystal cell has birefringence, and has a refractive index in the thickness direction and a surface direction. Because the refractive index is different, the linearly polarized light that has passed through the incident-side polarizing plate is transmitted through the normal line of the liquid crystal cell without being phase-shifted, but the linearly polarized light that has passed through the incident-side polarizing plate. Among them, the light incident in the direction inclined from the normal line of the liquid crystal cell has a phase difference when passing through the liquid crystal cell and becomes elliptically polarized light. This phenomenon is caused by the fact that the liquid crystal molecules aligned in the vertical direction in the liquid crystal cell act as a positive C plate. Note that the magnitude of the phase difference generated with respect to the light transmitted through the liquid crystal cell (transmitted light) depends on the birefringence value of the liquid crystal molecules enclosed in the liquid crystal cell, the thickness of the liquid crystal cell, the wavelength of the transmitted light, etc. Is also affected.

  Due to such a phenomenon, even if a certain cell in the liquid crystal cell is in a non-driven state, the linearly polarized light is transmitted as it is and should be blocked by the polarizing plate on the output side. A part of the light emitted in the direction inclined from the line leaks from the polarizing plate on the emission side. For this reason, in the conventional liquid crystal display device, the image display quality observed mainly from the direction inclined from the normal line of the liquid crystal cell, mainly the contrast, may be lower than the image observed from the front.

  Further, the display quality of the liquid crystal display device may be deteriorated due to the refractive index anisotropy exhibited by the liquid crystal cell and the viewing angle caused by the apparent angle change due to the viewing angle with the polarizing plate. This viewing angle dependency is a change in the color and contrast of an image viewed when the liquid crystal display device is viewed from the front and when viewed from an oblique direction. Along with the screen, it has become a serious concern.

As a typical method for improving the viewing angle dependency, a retardation film is used. This retardation film is disposed between the liquid crystal cell and the second polarizing plate between the first polarizing plate and the liquid crystal cell. By using the retardation film, a liquid crystal display device excellent in viewing angle characteristics can be easily obtained. For example, in Patent Document 1 (International Publication No. 2003/032060), in a VA liquid crystal display device, a retardation film having properties as an optically negative C plate and an optically positive A plate are used. What used together the retardation film which has a property is proposed. However, there is still a demand for the development of a liquid crystal display device with improved (front) contrast and improved image quality.
International Publication No. 2003/032060 Pamphlet

  In the liquid crystal display device including the first polarizing plate, the liquid crystal cell, and the second polarizing plate at the time of the invention, the present inventors each of the refractive indexes in the three-dimensional direction in the in-plane direction of the retardation layer of the phase difference body. And having a specific numerical relationship between the in-plane retardation in the retardation layer of the liquid crystal cell and the phase difference body, the (front) contrast can be increased in a high dimension. It has been found that a liquid crystal display device capable of improving and achieving excellent image quality can be obtained. The present invention has been made based on such knowledge.

Therefore, the liquid crystal display device according to the present invention comprises the first polarizing plate, the liquid crystal cell, and the second polarizing plate in this order,
A retardation member disposed between the liquid crystal cell and the first polarizer or between the liquid crystal cell and the second polarizer;
The first polarizing plate comprises a first polarizer and a polarizing plate protective film formed on both surfaces of the first polarizer,
The second polarizing plate comprises a second polarizer and a polarizing plate protective film formed on both surfaces of the second polarizer,
In the in-plane direction of the retardation layer in the retardation layer, the refractive indices in the x and y directions orthogonal to each other are defined as nx and ny, and in the thickness direction of the retardation layer, the refractive index in the z direction is defined as nz. The following general formula (I):
nx ≧ ny> nz (I)
And satisfying
When the in-plane retardation of the liquid crystal cell is defined as Re (Cell) and the in-plane retardation of the phase difference body is defined as Re (C), the following general formula (II):
Re (Cell)> Re (C) (II)
Is satisfied.

  Since the present invention has the technical features described above, it is possible to provide a liquid crystal display device that can achieve contrast, image quality, and image reproducibility at a high level.

Definitions Terms used in the present invention mainly have the following meanings.
1) In the in-plane direction of the retardation layer, the refractive indexes in the x and y directions orthogonal to each other are defined as nx and ny, and in the thickness direction of the retardation layer, the refractive index in the z direction is defined as nz. A phase difference body having a phase difference layer satisfying the following general formula: nx ≧ ny> nz (I) has properties as a so-called optically negative C plate.
2) “In-plane retardation (Re) in the in-plane direction” is the refractive index in the fast axis direction (the direction in which the refractive index is the smallest) in the plane of the retardation layer (retarder) or liquid crystal cell, etc. When the refractive index in the slow axis direction (direction in which the refractive index is the largest) is defined as ny and the thickness of the retardation layer (retarder) or the liquid crystal cell is defined as d (nm), Re = (nx −ny) × d.
Further, the “in-plane retardation (Rth) in the thickness direction” is a value represented by the formula Rth = {(nx + ny) / 2−nz} × d under the above conditions.
Re and Rth can be measured by, for example, a parallel Nicol rotation method using RETS-100 manufactured by Otsuka Electronics Co., Ltd. or KOBRA-WR manufactured by Oji Scientific Instruments. The value may vary depending on the wavelength to be measured and the measurement angle. In the present invention, unless otherwise noted, Re is a light having a wavelength of 589 nm in the thickness direction in an environment of 23 ° C. and 55% RH. The value shall be meant when measured in parallel.
4) “Haze value” is a value measured according to JIS K7105. A product name: NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd. can be used for the measurement of the haze value. Further, the “transmittance” of the “light-transmitting substrate” indicates a value obtained by measurement according to JIS K7361-1 (Testing method for total light transmittance of plastic transparent material).

I. Liquid crystal display
1. Outline The liquid crystal display device according to the present invention includes a first polarizing plate, a liquid crystal cell, and a second polarizing plate in this order. 1 can be used for explanation. In FIG. 1, light is incident from the light source of the backlight unit from the bottom, and the image is recognized from the top. FIG. 1 is a schematic sectional view showing an example of a liquid crystal display device according to the present invention. According to FIG. 1, a liquid crystal display device 100 according to the present invention includes an incident-side polarizing plate 102A (first polarizer or second polarizer), a liquid crystal cell 104, and an outgoing-side polarizing plate 102B (second polarizer or First polarizer). In the present invention, a phase difference body (40A, 40B) is further provided between the liquid crystal cell 104 and the incident-side polarizing plate 102A or between the liquid crystal cell 104 and the output-side polarizing plate 102B. is there. Moreover, a polarizing plate protective film is formed on both surfaces of the polarizer constituting the polarizing plate 102A and the polarizing plate 102B (not shown).

2. Characteristics The liquid crystal display device according to the present invention has the following technical characteristics.
1) Retardation layer In the present invention, in the in-plane direction of the phase difference layer of the phase difference body, the refractive indexes in the x and y directions orthogonal to each other are nx and ny, and in the thickness direction of the phase difference layer. When the refractive index in the z direction is defined as nz, the following general formula (I): nx ≧ ny> nz (I) is satisfied. The phase difference body having a phase difference layer satisfying the general formula (I) has a property as a so-called optically negative C plate.

2) Liquid crystal cell and phase difference body The liquid crystal display device according to the present invention further defines the in-plane retardation of the liquid crystal cell as Re (Cell) and the in-plane retardation of the phase difference body as Re (C). The following general formula (II):
Re (Cell)> Re (C) (II)
Is satisfied.
According to a preferred aspect of the present invention, when the in-plane retardation of the liquid crystal cell is defined as Re (Cell) and the in-plane retardation of the phase difference body is defined as Re (C), the following general formula (III):
0.05 <Re (C) / Re (Cell) <1 (III)
A liquid crystal display device that satisfies the above is proposed.

  When the in-plane retardation of the liquid crystal cell is Re (Cell) and the in-plane retardation of the phase difference body is Re (C), the above formula is satisfied, thereby obtaining a liquid crystal display device having excellent viewing angle characteristics. it can. In addition, according to the present invention, the phase difference film having the property as an optically positive A plate, which has been essential for the conventional VA liquid crystal display device, is not required. Can be simplified. Conventionally, the process of strictly matching the slow axis of the retardation film and the transmission axis of the polarizing plate, which has been a cause of complicating the production process, can be eliminated. For this reason, according to the present invention, it is possible to obtain a liquid crystal display device that can be manufactured at a low cost in a simple process capable of realizing high productivity.

3) Strength ratio (I / I)
According to a preferred aspect of the present invention, the surface of the retardation layer has an angle (2θ) when the angle formed by the extension line of the incident X-ray and the reflected X-ray is (2θ) in the X-ray diffraction chart in the reflection method. the intensity _{I 8.5} 2 [Theta]) is at 8.5 °, angle (2 [Theta]) is the ratio _I 8.5 _{/ I 17.0} of 17.0 ° intensity _{I 17} 0.00 exceeded 1.60, preferably Is preferably 1.20 or more and 1.50 or less. According to another preferred embodiment of the present invention, the ratio I ₁₄ / I _17.0 of the intensity I ₁₄ at an angle (2θ) of 14.0 ° and the intensity I ₁₇ at an angle (2θ) of 17.0 °. Is more than 0 and not more than 1.10, preferably the lower limit is not less than 1.00. By using a light-transmitting substrate whose intensity ratio is the above-mentioned numerical value, it is not necessary to subject the light-transmitting substrate to an alignment treatment or to form an alignment layer, thereby facilitating the manufacturing process. It becomes possible.

3. The liquid crystal display device according to the configuration present invention includes a first polarizer, a liquid crystal cell, a second polarizer, formed by basically formed by a phase Satai.
1) the phase difference member the phase Satai has a light transmitting substrate, formed by basically formed by the phase difference layer.
Re
According to a preferred embodiment of the present invention, the absolute value of the in-plane retardation Re (C) of the phase difference body is 5 nm or less, preferably 3 nm or less, more preferably 1 nm or less. Since the Re (C) value is within the above range, the retardation member of the present invention can be used as a suitable retardation member for improving the viewing angle characteristics of a VA liquid crystal display element. is there. The Re (C) value may have wavelength dependency. For example, a mode in which the Re (C) value is larger on the long wavelength side than that on the short wavelength side may be used, and a mode in which the Re (C) value is larger on the short wavelength side than on the long wavelength side may be used. By having the wavelength dependency of the Re (C) value, for example, when the retardation member of the present invention is used as a retardation member for improving the viewing angle characteristics of a liquid crystal display element, The viewing angle characteristics of the liquid crystal display element can be improved over the entire area.

Rth
The in-plane retardation (Rth) in the thickness direction of the phase difference body is in the range of about 50 nm to about 400 nm, preferably the lower limit is in the range of 100 nm and the upper limit is in the range of about 300 nm. When Rth is within the above range, in combination with the A plate, the phase difference body of the present invention can be obtained, and a phase difference body suitable for improving the viewing angle characteristics of the VA liquid crystal display device can be obtained. it can.

Light transmissive substrate The light transmissive substrate may be a flexible material having flexibility or a rigid material having no flexibility, but a flexible material is preferred. By using the flexible material, the phase difference body can be manufactured by a roll-to-roll process, and productivity can be improved. Flexible materials include cellulose derivatives, norbornene polymers, cycloolefin polymers, polymethyl methacrylate, polyvinyl alcohol, polyimide, polyarylate, polyethylene terephthalate, polysulfone, polyethersulfone, amorphous polyolefin, modified acrylic polymer, polystyrene, epoxy resin , Polycarbonate, polyesters and the like.

  According to a preferred embodiment of the present invention, it is preferable to use a cellulose derivative. Since the cellulose derivative is particularly excellent in optical isotropy, a retardation body excellent in optical characteristics can be obtained. In particular, a cellulose derivative is preferable because it has a characteristic that it has a surface orientation property in which rod-shaped compounds having refractive index anisotropy are randomly arranged on the surface of the cellulose derivative. Since the cellulose derivative itself has the above-described surface orientation, it does not require an orientation layer and is economical. Furthermore, the cellulose derivative is particularly excellent in optical isotropy, and can impart optical isotropy to the phase difference body. That is, the cellulose derivative generally has a function as an optically negative C-plate. The light-transmitting substrate made of the cellulose derivative also has a function as a so-called alignment film so that the rod-shaped compound can easily form a random alignment. From this, the phase difference body by this invention becomes easy for the rod-shaped compound contained in a phase difference layer to form random homogeneous orientation, when a phase difference layer is formed on this transparent base material.

  The cellulose derivative is a flexible material having flexibility, and the production process of the phase difference body can be a roll-to-roll method, which is excellent in productivity. Specific examples of the cellulose derivative include cellulose esters, and among them, cellulose acylates are preferable. Specific examples of cellulose acylates preferably include lower fatty acid esters having 2 to 4 carbon atoms, and among them, those containing only a single lower fatty acid ester, such as cellulose acetate, It may contain a plurality of lower fatty acid esters such as cellulose acetate butyrate and cellulose acetate propionate. In the present invention, cellulose acetate is particularly preferably used among the lower fatty acid esters. Among cellulose acetates, it is most preferable to use triacetyl cellulose having an average acetylation degree of 57.5 to 62.5% (substitution degree: 2.6 to 3.0). Here, “degree of acetylation” means the amount of bound acetic acid per unit mass of cellulose. The degree of acetylation can be determined by measurement and calculation of the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like). Specifically, the degree of acetylation of triacetyl cellulose, which is an example of a cellulose derivative, can be obtained by the above measurement after removing impurities such as a plasticizer contained in the structure.

  Triacetylcellulose has a molecular structure with relatively bulky side chains. From this, when the composition for a retardation layer containing a rod-shaped compound is applied to a light-transmitting substrate made of triacetylcellulose, it penetrates into the light-transmitting substrate, and as a result, the light-transmitting substrate and Adhesion with the retardation layer can be improved. In addition, triacetyl cellulose easily develops the properties of an optically negative C plate, so that it becomes easy to form a random homogeneous orientation of the rod-shaped compound.

  The light transmissive substrate may be composed of a single layer or a plurality of layers made of a cellulose derivative. In the case of a plurality of layers, the light transmissive substrate may be formed of layers of the same or different materials. The transparency of the light-transmitting substrate may be arbitrarily determined according to the transparency required for the phase difference body of the present invention, but it is usually preferable that the transmittance in the visible light region is 80% or more. 90% or more is more preferable. The thickness of the light-transmitting substrate can be appropriately determined according to the use of the phase difference body, but is preferably in the range of 10 μm to 188 μm, particularly preferably in the range of 20 μm to 125 μm, and particularly in the range of 30 μm to 80 μm. It is preferable to be within. When the thickness of the substrate is within the above range, the function as a support in the phase difference body can be exhibited, and the production is facilitated.

  The light-transmitting substrate preferably has a thickness direction retardation (Rth) in the range of 20 nm to 100 nm, particularly preferably in the range of 25 nm to 80 nm, and more preferably in the range of 30 nm to 60 nm. It is preferable to be within the range. When Rth is within the above range, a homogeneous random homogeneous orientation can be formed regardless of the type of the rod-shaped compound. Preferably, the light-transmitting substrate preferably has an in-plane retardation (Re) in the range of 0 nm to 300 nm, particularly in the range of 0 nm to 150 nm, in addition to the Rth being in the above range. It is preferable to be within the range, and it is particularly preferable to be within the range of 0 nm to 125 nm.

Retardation layer
The thickness of the layer thickness retardation layer is not particularly limited as long as it is within the range in which the kind of rod-shaped compound and desired optical characteristics can be imparted. The thickness of the retardation layer is preferably in the range of 0.5 μm to 10 μm, more preferably in the range of 0.5 μm to 5 μm, and particularly preferably in the range of 1 μm to 3 μm. When the thickness of the retardation layer is within the above range, it is possible to exhibit optical anisotropy matched to the type of rod-shaped compound, and one of the characteristics of random homogeneous orientation is “in-plane orientation”. As a result, sufficient optical characteristics can be obtained. Here, the thickness of the retardation layer does not include the thickness of the mixed region in the case where the adhesive layer between the retardation layer and the light transmissive substrate has a mixed region where both are “mixed”.

Re, Rth
The retardation (Re) of the retardation layer in the present invention is preferably in the range of 0 nm to 5 nm as described above from the viewpoints of “irregularity” and “in-plane orientation” possessed by random homogeneous orientation. The range of 0 nm to 3 nm is preferable, and the range of 0 nm to 1 nm is particularly preferable.

  In the present invention, the retardation (Rth) in the thickness direction of the retardation layer is preferably in the range of 50 nm to 400 nm as described above from the viewpoint of “in-plane orientation” possessed by random homogeneous orientation, and in particular, 50 nm to 300 nm. Is preferably within the range of 50 nm to 200 nm. The retardation layer in the present invention has a value (Rth / d) obtained by dividing the retardation value (Rth (nm)) in the thickness direction of the retardation layer by the thickness (d (μm)) of the retardation layer. Is preferably in the range of ˜13, more preferably in the range of 0.5 to 10, and particularly preferably in the range of 0.5 to 7.

Haze value of haze values retardation layer random homogeneous alignment comprises in terms of "dispersible", as described above, it is preferably in the range of 0% to 5%, in the range Of these 0% to 1% is Particularly preferred is a range of 0% to 0.5%.

Composition and Formation The configuration of the retardation layer in the present invention may have a configuration in which a single layer or a plurality of layers are laminated. When it has the structure by which the several layer was laminated | stacked, the same or different composition may be sufficient. When the retardation layer is composed of a plurality of layers, it is sufficient that at least the retardation layer directly laminated on the substrate has a rod-like compound in which random homogeneous orientation is formed. The retardation layer can be formed by using a composition for a retardation layer containing other materials such as a rod-like compound having refractive index anisotropic optics and a resin.
The rod-like compound retardation layer comprises a rod-like compound having refractive index anisotropy. Preferably, this rod-shaped compound is formed by forming a random homogeneous orientation in the retardation layer. By having such an alignment state, the phase difference body of the present invention can be made excellent in optical characteristics.
This random homogeneous orientation has at least the following three characteristics. That is, 1] First, when the phase difference layer is viewed from the direction perpendicular to the surface of the phase difference layer, the arrangement direction of the rod-like compounds is random (hereinafter, simply referred to as “irregularity”). 2) Second, the size of the domain formed by the rod-shaped compound in the retardation layer is smaller than the wavelength in the visible light region (hereinafter, sometimes simply referred to as “dispersibility”), 3) 3 is that the rod-like compound is in-plane oriented in the retardation layer (hereinafter, sometimes simply referred to as “in-plane orientation”).

  Random homogeneous orientation can be described with reference to FIG. FIG. 3A is a schematic view when the phase difference body of the present invention is viewed from the direction perpendicular to the surface of the phase difference layer represented by A in FIG. 3B and 3C are cross-sectional views taken along line B-B 'in FIG.

  1] The first feature, “irregularity”, will be described with reference to FIG. As shown in FIG. 3A, the “irregularity” indicates that the rod-like compound in the retardation layer 2 when the retardation member 10 of the present invention is viewed from the direction perpendicular to the surface of the retardation layer 2. 3 indicates that they are randomly arranged. Here, in the present invention, in order to explain the arrangement direction of the rod-shaped compound 3, the molecular major axis direction (hereinafter referred to as molecular axis) represented by a in FIG. . Therefore, that the arrangement direction of the rod-shaped compounds is random means that the molecular axes a of the rod-shaped compounds 3 included in the retardation layer are randomly oriented.

  In addition to the arrangement state illustrated in FIG. 3 (a), even if the rod-shaped compound has a cholesteric structure, the direction of the molecular axis a is random as a whole. Although it corresponds to “regularity”, the “irregularity” in the present invention does not include a form caused by a cholesteric structure.

  2] The second feature, “dispersibility”, will be described with reference to FIG. As shown in FIG. 3A, “dispersibility” means that when the rod-shaped compound 3 forms the domain b in the retardation layer 2, the size of the domain b is smaller than the wavelength in the visible light region. Is shown. In the present invention, the smaller the size of the domain b is, the more preferable, and the state where the rod-like compound is dispersed in a single molecule is the most preferable.

  3] A third feature, “in-plane orientation”, will be described with reference to FIG. As shown in FIG. 2B, the “in-plane orientation” is such that the rod-shaped compound 3 in the retardation layer 2 has the molecular axis a substantially perpendicular to the normal direction A of the retardation layer 3. Means oriented. As “in-plane orientation” in the present invention, as shown in FIG. 2B, the molecular axes a of all the rod-like compounds 3 in the retardation layer 2 are substantially perpendicular to the normal direction A. For example, as shown in FIG. 3C, even if the rod-like compound 3 whose molecular axis a ′ is not perpendicular to the normal direction A is present in the retardation layer 2, This includes the case where the average direction of the molecular axis a of the rod-shaped compound 3 existing in the retardation layer 2 is substantially perpendicular to the normal direction A.

Example of rod-shaped compound The rod-shaped compound in the present invention is not particularly limited as long as it can form a random homogeneous alignment in the retardation layer. The “rod-like compound” in the present invention refers to a rod having a main skeleton of the molecular structure, and examples of the compound having such a rod-like main skeleton include azomethines, azoxys, cyanobiphenyls, cyano 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 can be mentioned. . Moreover, not only the above low molecular liquid crystalline compound but a high molecular liquid crystalline compound can also be used.

  As the rod-like compound, a compound having a relatively small molecular weight is preferably used. Specifically, a compound having a molecular weight in the range of 200 to 1200, particularly in the range of 400 to 800 is preferably used. When the molecular weight is within the above range, the rod-shaped compound easily penetrates into the substrate described later, and therefore, it becomes easier to form a “mixed” state at the adhesion site between the substrate and the retardation layer. Adhesion with the layer can be improved.

  The rod-shaped compound is preferably a liquid crystalline material exhibiting liquid crystallinity. When the rod-like compound is a liquid crystalline material, the retardation layer can be made excellent in the expression of optical characteristics per unit thickness. Further, the rod-like compound is preferably a liquid crystal material exhibiting a nematic phase. This is because a liquid crystalline material exhibiting a nematic phase is relatively easy to form a random homogeneous alignment. Furthermore, the liquid crystalline material exhibiting a nematic phase is preferably a molecule having spacers at both ends of the mesogen. Since such a liquid crystalline material is excellent in flexibility, it is possible to effectively prevent the retardation layer in the present invention from becoming cloudy.

  As the rod-like compound, those having a polymerizable functional group in the molecule are preferably used, and among them, those having a polymerizable functional group capable of three-dimensional crosslinking are preferable. Since the rod-shaped compound has a polymerizable functional group, it becomes possible to polymerize and fix the rod-shaped compound. Therefore, by fixing the rod-shaped compound in a state of forming a random homogeneous orientation, it is possible to improve the array stability. This is because a phase difference body that is excellent and hardly changes in optical characteristics can be obtained. In the present invention, a rod-shaped compound having a polymerizable functional group and a rod-shaped compound having no polymerizable functional group may be mixed and used. Here, “three-dimensional crosslinking” means that liquid crystalline molecules are polymerized in three dimensions to form a network (network) structure.

  Such a polymerizable functional group is not particularly limited, and various polymerizable functional groups that are polymerized by the action of ionizing radiation such as ultraviolet rays and electron beams, or heat are used. Representative examples of these polymerizable functional groups include radically polymerizable functional groups or cationic polymerizable functional groups. Further, representative examples of radically polymerizable functional groups include functional groups having at least one addition-polymerizable ethylenically unsaturated double bond, and specific examples include vinyl groups having or not having substituents, An acrylate group (generic name including an acryloyl group, a methacryloyl group, an acryloyloxy group, and a methacryloyloxy group) and the like can be given. Specific examples of the cationic polymerizable functional group include an epoxy group. In addition, examples of the polymerizable functional group include an isocyanate group and an unsaturated triple bond. Among these, from the viewpoint of the process, a functional group having an ethylenically unsaturated double bond is preferably used.

  In the present invention, the rod-like compound is a liquid crystalline material exhibiting liquid crystallinity and particularly preferably has a polymerizable functional group at the terminal. For example, if nematic liquid crystalline materials having polymerizable functional groups at both ends are used, they can be polymerized three-dimensionally to form a network structure, have alignment stability, and have optical properties. It is possible to obtain a retardation layer excellent in the expression of. Moreover, even if it has a polymerizable functional group at one end, it can be cross-linked with other molecules to stabilize the sequence. Examples of such rod-shaped compounds include compounds represented by the following formulas (1) to (6).

Liquid crystalline materials represented by the chemical formulas (1), (2), (5) and (6) are disclosed in DJ Broer et al., Makromol. Chem. 190, 3201-3215 (1989), or DJ Broer et al., Makromol. Chem. 190, 2250 (1989), or can be prepared similarly. The preparation of liquid crystalline materials represented by the chemical formulas (3) and (4) is disclosed in DE 195,04,224.
Specific examples of the nematic liquid crystalline material having an acrylate group at the terminal include those represented by the following chemical formulas (7) to (17).

  You may use a rod-shaped compound 1 type or in mixture of 2 or more types. For example, as a rod-shaped compound, when a liquid crystalline material having one or more polymerizable functional groups at both ends and a liquid crystalline material having one or more polymerizable functional groups at one end are mixed and used, It is preferable because the polymerization density (crosslinking density) and optical characteristics can be arbitrarily adjusted by adjusting the above.

Other compounds The retardation layer in the present invention may contain other compounds in addition to the rod-like compound. Such other compounds are not particularly limited as long as they do not disturb the random homogeneous orientation of the rod-shaped compound. Examples of such other compounds include polymerizable materials.

  Examples of the polymerizable material include a polyester (meth) acrylate obtained by reacting a (meth) acrylic acid with a polyester prepolymer obtained by condensing a polyhydric alcohol and a monobasic acid or a polybasic acid; a polyol group. And a compound having two isocyanate groups are reacted with each other, and then a polyurethane (meth) acrylate obtained by reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, Epoxy resins such as novolac type epoxy resin, polycarboxylic acid polyglycidyl ester, polyol polyglycidyl ether, aliphatic or cycloaliphatic epoxy resin, amino group epoxy resin, triphenolmethane type epoxy resin, dihydroxybenzene type epoxy resin, ( Meta) Acry Photopolymerizable compound in epoxy (meth) acrylate obtained by reacting an acid; may be mentioned a photopolymerizable liquid crystal compound, such as having an acrylic group or a methacrylic group.

Other Layers The phase difference body according to the present invention can include, for example, an antireflection layer, an ultraviolet absorption layer, an infrared absorption layer, an antistatic layer, and the like as other layers. The antireflection layer is not particularly limited. For example, the antireflection layer is formed by forming a low refractive index layer made of a substance having a lower refractive index than the base material on the light transmissive base material, or on the light transmissive base material. A high refractive index layer made of a material having a higher refractive index than that of the base material and a low refractive index layer made of a material having a lower refractive index than that of the base material are alternately laminated in this order. And the like. These high-refractive index layers and low-refractive index layers are vacuum-deposited so that the optical thickness represented by the product of the geometric thickness and refractive index of the layer is 1/4 of the wavelength of light to be prevented from being reflected. It is formed by coating or the like.

As the constituent material of the high refractive index layer, titanium oxide, zinc sulfide and the like are used, and as the constituent material of the low refractive index layer, magnesium fluoride, cryolite and the like are used. Examples of the ultraviolet absorbing layer include a film formed by adding an ultraviolet absorber made of a benzotriazole-based compound, a benzophenone-based compound, a salicylate-based compound, or the like into a body such as a polyester resin or an acrylic resin.
As an infrared absorption layer, what formed the infrared absorption layer by coating etc. on body base materials, such as a polyester resin, is mentioned. Further, as the external line absorption layer, for example, a film formed by adding an infrared absorbent made of a diimmonium compound, a phthalocyanine compound or the like into a binder resin made of an acrylic resin, a polyester resin or the like is used.

  Examples of the antistatic layer include various cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium salts, and primary to tertiary amino groups; sulfonate groups, sulfate ester bases, phosphorus Anionic antistatic agents having an anionic group such as acid ester base and phosphonic acid base; Amphoteric antistatic agents such as amino acid type and amino sulfate ester type; Nonionic charge such as amino alcohol type, glycerin type and polyethylene glycol type An antistatic agent; a polymeric antistatic agent obtained by increasing the molecular weight of an antistatic agent; a monomer or an oligomer having a tertiary amino group or a quaternary ammonium group and capable of being polymerized by ionizing radiation, such as N, N- Add antistatic agents such as polymerizable antistatic agents such as dialkylaminoalkyl (meth) acrylate monomers and their quaternary compounds Which was formed Te, and the like.

Basic characteristics of phase difference body
The thickness of the thickness phase difference body is not particularly limited as long as it is within a range in which desired optical characteristics can be expressed, but usually within a range of 10 μm to 200 μm, particularly preferably within a range of 20 μm to 100 μm. .

Mixed region Since the phase difference body according to the present invention is characterized in that the phase difference layer is directly formed on the substrate, the rod-shaped compound contained in the phase difference layer penetrates into the light transmissive substrate, and A mixed region in which both are “mixed” is formed at the bonding portion between the base material and the retardation layer. The thickness of such a mixed region is not particularly limited as long as random homogeneous orientation can be formed and the adhesion between the base material and the retardation layer can be within a desired range. In particular, in the present invention, the thickness of the mixed region is preferably in the range of 0.1 μm to 10 μm, particularly preferably in the range of 0.5 μm to 5 μm, and in particular in the range of 1 μm to 3 μm. Preferably there is.

  The distribution state of the rod-shaped compound in the mixed region is not particularly limited as long as the random homogeneous orientation can be formed and the adhesion between the base material and the retardation layer can be within a desired range. Examples of the distribution state of the rod-shaped compound include an aspect that exists uniformly in the thickness direction of the base material and an aspect that has a concentration gradient with respect to the thickness direction of the base material. It can be used suitably. The existence confirmation of the mixed region and the confirmation of the distribution state of the rod-like compound in the mixed region can be confirmed by the TOF-SIMS method.

The haze value of the haze value phase difference body is preferably in the range of 0% to 5%, particularly preferably in the range of 0% to 1%, and in particular in the range of 0% to 0.5%. It is preferable that

  The phase difference body of this invention can be used for the use as a negative C plate. Thus, when used as an optical compensator which is a negative C plate, it is suitably used for a liquid crystal display device having a liquid crystal layer such as a VA mode or an OCB mode.

Method for producing phase difference body The method for producing a phase difference body according to the present invention comprises a cellulose derivative and a surface orientation in which rod-like compounds having refractive index anisotropy are randomly arranged on the surface of the light-transmitting substrate. The light-transmitting substrate having the property is prepared. And the composition for retardation layers containing the said rod-shaped compound is provided to the surface of this transparent base material, and the said composition for retardation layers is hardened | cured as needed, and a retardation layer is formed. Is included.

Retardation Layer Composition The retardation layer composition comprises a rod-shaped compound, other compounds, optional components, and a solvent. By using a solvent, it becomes possible to permeate the rod-shaped compound into the light-transmitting substrate together with the solvent. As a result, the interaction between the rod-shaped compound and the material constituting the substrate can be strengthened. It becomes easy to form a random homogeneous orientation.

The solvent is not particularly limited as long as it can dissolve the rod-like compound at a desired concentration. Examples of the solvent used in the present invention include hydrocarbon solvents such as benzene and hexane, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, ether solvents such as tetrahydrofuran and 1,2-dimethoxyethane, chloroform, Illustrate alkyl halide solvents such as dichloromethane, ester solvents such as methyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, amide solvents such as N, N-dimethylformamide, and sulfoxide solvents such as dimethyl sulfoxide. 1 type, or 2 or more types of mixed solvents may be sufficient. Among these solvents, it is preferable to use a ketone solvent, and among them, cyclohexane is preferably used.

Content of rod-shaped compound The content of the rod-shaped compound is preferably in the range of 0.1% by mass to 60% by mass, particularly preferably in the range of 1% by mass to 50% by mass, in the total amount of the composition for the retardation layer. Especially, it is preferable that it exists in the range of 10 mass%-40 mass%.

The composition for an optional component retardation layer can comprise the following optional components.
The composition for a photopolymerization initiator retardation layer may contain a photopolymerization initiator as necessary. In particular, when a treatment for curing the retardation layer by ultraviolet irradiation is performed, it is preferable to include a photopolymerization initiator. Examples of the photopolymerization initiator used in the present invention include benzophenone, methyl o-benzoylbenzoate, 4,4-bis (dimethylamine) benzophenone, 4,4-bis (diethylamine) benzophenone, α-amino acetophenone, 4, 4-dichlorobenzophenone, 4-benzoyl-4-methyldiphenyl ketone, dibenzyl ketone, fluorenone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone P-tert-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyldimethyl ketal, benzylmethoxyethyl acetal Benzoin methyl ether, benzoin butyl ether, anthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, anthrone, benzanthrone, dibenzsuberone, methyleneanthrone, 4-azidobenzylacetophenone, 2,6-bis (p- Azidobenzylidene) cyclohexane, 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 2-phenyl-1,2-butadion-2- (o-methoxycarbonyl) oxime, 1-phenyl-propanedione-2 -(O-ethoxycarbonyl) oxime, 1,3-diphenyl-propanetrione-2- (o-ethoxycarbonyl) oxime, 1-phenyl-3-ethoxy-propanetrione-2- (o-benzoy ) Oxime, Michler's ketone, 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone, Naphthalenesulfonyl chloride, quinolinesulfonyl chloride, n-phenylthioacridone, 4,4-azobisisobutyronitrile, diphenyldisulfide, benzthiazole disulfide, triphenylphosphine, camphorquinone, Adeka N1717, carbon tetrabromide, Examples include combinations of photoreducing dyes such as tribromophenylsulfone, benzoin peroxide, eosin, and methylene blue with reducing agents such as ascorbic acid and triethanolamine. In this invention, these photoinitiators can be used 1 type or in combination of 2 or more types.

Photopolymerization initiation assistant When a photopolymerization initiator is used, a photopolymerization initiation assistant can be used in combination. Examples of such photopolymerization initiation assistants include tertiary amines such as triethanolamine and methyldiethanolamine, and benzoic acid derivatives such as ethyl 2-dimethylaminoethylbenzoate and ethyl 4-dimethylamidebenzoate. Yes, but not limited to these.

A compound as shown below can be added to an arbitrary composition for a retardation layer within a range that does not impair the object of the present invention. Examples of compounds that can be added include polyester (meth) acrylate obtained by reacting (meth) acrylic acid with a polyester prepolymer obtained by condensing polyhydric alcohol and monobasic acid or polybasic acid; A polyurethane (meth) acrylate obtained by reacting a compound having two isocyanate groups with each other and then reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak Type epoxy resins, polycarboxylic acid polyglycidyl esters, polyol polyglycidyl ethers, aliphatic or cycloaliphatic epoxy resins, amino group epoxy resins, triphenolmethane type epoxy resins, dihydroxybenzene type epoxy resins and the like (meta Acu Photopolymerizable compounds such as epoxy (meth) acrylate obtained by reacting Le acid; photopolymerizable liquid crystal compound having an acryl group or methacryl group and the like. The addition amount of these compounds with respect to the composition for retardation layers can be determined in the range which does not impair the objective of this invention. By adding an arbitrary compound, the mechanical strength of the retardation layer is improved and the stability is improved.

Forming Method Any method may be used as a method for forming a retardation layer from a composition for a retardation layer as long as the composition for a retardation layer is applied to the surface of a light-transmitting substrate. Examples of the method include a method of applying a coating method. As the coating method, for example, gravure coating method, reverse coating method, knife coating method, dip coating method, spray coating method, air knife coating method, spin coating method, roll coating method, printing method, immersion pulling method, curtain coating method Examples thereof include a die coating method, a casting method, a bar coating method, an extrusion coating method, and an E-type coating method.

  The thickness of the coating film of the phase difference layer composition is not particularly limited as long as the desired flatness can be achieved. Usually, the thickness is preferably in the range of 0.1 μm to 50 μm, and particularly preferably about 0. The range of 5 μm to 30 μm is preferable, and the range of 0.5 μm to 10 μm is particularly preferable. Moreover, the drying method of the coating film of the composition for phase difference layers can use commonly used drying methods, such as a heat drying method, a reduced pressure drying method, and a gap drying method. In addition, the drying method in the present invention is not limited to a single method, and a plurality of drying methods may be employed, for example, by changing the drying method sequentially according to the amount of solvent remaining.

  When a polymerizable material is used as the rod-shaped compound, the method for polymerizing the polymerizable material is not particularly limited, and may be arbitrarily determined according to the type of polymerizable functional group that the polymerizable material has. In particular, in the present invention, a method of curing by irradiation with actinic radiation is preferable. The actinic radiation is not particularly limited as long as it is a radiation capable of polymerizing a polymerizable material, but it is usually preferable to use ultraviolet light or visible light from the viewpoint of the ease of the device, etc. Among them, it is preferable to use irradiation light having a wavelength of 150 to 500 nm, preferably 250 to 450 nm, and more preferably 300 to 400 nm. Low light mercury lamp (sterilization lamp, fluorescent chemical lamp, black light), high pressure discharge lamp (high pressure mercury lamp, metal halide lamp), short arc discharge lamp (super high pressure mercury lamp, xenon lamp, mercury xenon lamp) And the like. Among these, use of a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, etc. is recommended. The irradiation intensity can be appropriately adjusted according to the content of the photopolymerization initiator.

2) In the first polarizer / second polarizer present invention, a first and second polarizing plates. The basic configuration of the first polarizing plate and the second polarizing plate includes a first polarizer (second polarizer) and a polarizing plate protective film formed on both surfaces thereof. By combining the retardation film, the first polarizing plate, and the second polarizing plate, a polarizing material having an optical compensation function that improves the viewing angle characteristics of the liquid crystal display device can be obtained.

Although a polarizer polarizer is not specifically limited, For example, an iodine type polarizing layer, a dye type polarizing layer using a dichroic dye, a polyene type polarizing layer, etc. can be used. The iodine-based polarizing layer and the dye-based polarizing layer are generally produced using polyvinyl alcohol. Examples thereof include a polyvinyl alcohol film, a polyvinyl formal film, a polyvinyl acetal film, an ethylene-vinyl acetate copolymer saponified film, which are dyed with iodine or a dye and stretched.

Polarizing plate protective film Examples of the polarizing plate protective film include films (sheets) of cellulose derivatives, stretched polyester, polycarbonate, polymethyl methacrylate, polyvinyl chloride, saponified ethylene / vinyl acetate copolymer, polymethylpentene, and the like. . Preferably, it is a necessary condition that the optical function is excellent in haze, reflectance, light transmittance, image clarity, and there is no unevenness in the thickness of the sheet, and it is a necessary condition, and is manufactured by a casting method. Preferred are cellulose derivatives, particularly cellulose triacetate films. The polarizing plate can be produced by directly attaching the polarizer to the polarizing protective film or via an adhesive.

4) Liquid crystal cell The liquid crystal cell in the present invention may be a liquid crystal part that has been developed conventionally or will be developed in the future. According to a preferred embodiment of the present invention, the liquid crystal cell is preferably a vertical alignment liquid crystal cell (VA mode). A VA liquid crystal cell is formed by sealing vertically aligned liquid crystal between a pair of substrates. Since the VA liquid crystal cell used in the present invention has a configuration in which a vertical alignment type liquid crystal is enclosed, the VA liquid crystal cell as a whole has properties as an optically positive C plate. As the VA liquid crystal cell used in the present invention, a cell having desired optical characteristics can be selected and used according to the driving method of the liquid crystal display device of the present invention. It will be adjusted to be within the range defined by the invention. The VA liquid crystal cell may be a general one.

II. Manufacturing method and use of liquid crystal display device Manufactured by laminating a first polarizing plate, a liquid crystal cell, a second polarizing plate, and a retardation body (via an adhesive layer as necessary). can do. The liquid crystal display device according to the present invention can be used as an image display device by being joined to a backlight portion.

EXAMPLES The contents of the present invention will be described using the following examples, but the scope of the present invention should not be construed as being limited to these examples.

Example 1
Preparation of the first polarizing plate Pre-iodine-dyed, a polarizing plate protective film having an antireflection function on one side of the stretched PVA film, and a 80 μm thick triacetyl cellulose film (TF80UL manufactured by Fuji Film Co., Ltd.) on the opposite side, One polarizing plate was produced.

Production of the second polarizing plate Instead of the polarizing plate protective film having the antireflection function, the same as the first polarizing plate, except that the following retardation body having the function of an optically negative C plate was used. Two polarizing plates were produced.

Production of retardation body A retardation body having the function of an optically negative C plate was produced as follows.
As the light-transmitting substrate, a triacetylcellulose film (KC8UX2MW manufactured by Konica Minolta Co., Ltd.) having a thickness of 80 μm was used. As a refractive index anisotropic material, a photopolymerizable liquid crystal compound represented by the following chemical formula (I), and Irgacure 907 (manufactured by Ciba Geigy Co., Ltd.) as a polymerization initiator is 5 wt% with respect to the photopolymerizable liquid crystal compound. 20 wt% was dissolved to obtain a composition for a retardation layer. After coating this retardation layer composition on a light-transmitting substrate by a bar coating method and drying it in a 40 ° C. oven for 2 minutes, it was irradiated with 100 mJ / m ² of ultraviolet rays in a nitrogen atmosphere. A retardation member was prepared by forming a retardation layer having a thickness of 5 μm on the light-transmitting substrate.

Production of Liquid Crystal Display Device The first polarizing plate and the second polarizing plate were mounted on AQUAOS LC26GH3 manufactured by Sharp Corporation to produce a liquid crystal display device. The mounting method is such that the absorption axis of the first polarizing plate and the second polarizing plate are substantially perpendicular to each other, the absorption axis of the first polarizing plate is the horizontal direction of the screen, and the absorption axis of the second polarizing plate is the vertical direction with respect to the screen It was pasted together using an adhesive (CS9621 manufactured by Nitto Denko Corporation). A TAC is provided on the cell side of the first polarizing plate, and a negative C plate is provided on the cell side of the second polarizing plate.

Example 2
It produced similarly to Example 1 except having used the 80-micrometer-thick triacetyl-cellulose film (TF80UL by Fuji Film Co., Ltd.) as a light-transmitting base material of the negative C plate of a 2nd polarizing plate.

Comparative Example 1
It was produced in the same manner as in Example 1 except that a 80 μm thick triacetyl cellulose film (TD80ULH manufactured by Fuji Film Co., Ltd.) was used as the light transmissive substrate of the negative C plate of the second polarizing plate.

Comparative Example 2
It produced similarly to Example 1 except having used the 80-micrometer-thick triacetyl-cellulose film (FDY Film company make TDY80UL) as the light-transmissive base material of the negative C plate of a 2nd polarizing plate.

Evaluation test
Evaluation 1: In-plane retardation Re, Rth measurement evaluation Using a KOBRA-WR (manufactured by Oji Scientific Instruments Co., Ltd.), a parallel Nicol rotation method is used to measure light having a wavelength of 589 nm in an environment of 23 ° C. and 55% RH. Measurements were made with incidence parallel to the direction. After the measurement, the following 1) and 2) were performed.
1) In the in-plane direction of the phase difference layer of the phase difference body, the refractive indexes in the x and y directions orthogonal to each other are nx and ny, and in the thickness direction of the phase difference layer, the refractive index in the z direction is nz. I investigated the relationship.
2) The in-plane retardation Re (Cell) of the liquid crystal cell and the in-plane retardation Rth (Cell) in the thickness direction, and the in-plane retardation of the phase difference body are represented by Re (C) and the in-plane retardation Rth (thickness direction). C) and Re (C) / Re (Cell) was calculated. The unit of Re and Rth is “nm”. The obtained values are evaluated for superiority or inferiority in viewing angle characteristics according to the following criteria.
Excellent evaluation criteria : 0 <Re (C) / Re (Cell) ≦ 0.1
Good: 0.1 <Re (C) / Re (Cell) R ₀ ≦ 1
Normal: 1 <Re (C) / Re (Cell) R ₀ ≦ 9
Defect: 9 <Re (C) / Re (Cell) R ₀

Evaluation 2: X-ray diffraction evaluation test X-ray diffraction measurement in the reflection method was performed under the following measurement conditions, and in the X-ray diffraction chart, when the angle formed by the extension line of the incident X-ray and the reflected X-ray was 2θ, 1) Ratio I _8.5 / I _17.0 of intensity I _8.5 of 2θ = _8.5 ° and intensity I _17.0 of 2θ = 17.0 °, and 2) intensity of 2θ = 13.2 °. The ratio I _13.2 / I _14.8 of I _13.2 and the intensity I _14.8 of 2θ = 14.8 ° was determined. The numerical values obtained were evaluated according to the following criteria:
Measurement condition apparatus name: RIGAKU RINP-1500
X-ray source: Cu
Tube current: 150 mA
Tube voltage: 50 kV
Scanning speed: 5 ° / min
Divergent slit (DS: automatic) 1 °
Scattering slit (SS: automatic) 1 °
Receiving slit (RS: automatic) 0.3mm
Monochrome light receiving slit (RSm: Manual) 0.6mm
Evaluation criteria 1) I _8.5 / I _17.0 Evaluation excellence: 1.00 ≦ I _8.5 / I _17.0 ≦ 1.50
Good: 0.00 <I _8.5 / I _17.0 ≦ 1.60
Poor: 1.60 <I _8.5 / I _17.0
2) I _14.0 / I _17.0 evaluation
Excellent: 1.00 ≦ I _13.2 / I _14.8 ≦ 1.10.
Good: 0.00 <I _13.2 / I _14.8 ≦ 1.10.
Poor: 1.10 <I _13.2 / I _14.8

Evaluation 3 Contrast Evaluation Test (Front) As a contrast evaluation, the luminance of the liquid crystal display device was measured. The measurement was performed in a dark room from the normal direction to the display screen of the liquid crystal display device using a color luminance meter BM-5A manufactured by Topcon Corporation. The numerical values obtained were evaluated according to the following criteria:
Evaluation Criteria 1) I _8.5 / I _17.0 Evaluation Excellent: 640 ≦ Contrast Value Good: 610 <Contrast Value
Defect: Contrast value ≦ 610

It is the schematic showing an example of the liquid crystal display device by this invention. It is a schematic sectional drawing which shows an example of the phase difference body used for this invention. It is a schematic sectional drawing which shows the other example of the phase difference body used for this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light transmissive base material 2 ... Phase difference layer 3 ... Rod-shaped compound 100 ... Liquid crystal display device 40A, 40B ... Phase difference body 102A, 102B ... Polarizing plate 104 ... Liquid crystal cell

Claims (6)

A vertical alignment type liquid crystal display device comprising a first polarizing plate, a vertical alignment type liquid crystal cell, and a second polarizing plate in this order,
Further comprising becomes with the said vertical alignment type liquid crystal cell first polarizer between, and one or arranged phase Satai both between the second polarizer and the vertical alignment type liquid crystal cell,
The first polarizing plate comprises a first polarizer and a polarizing plate protective film formed on both surfaces of the first polarizer,
The second polarizing plate comprises a second polarizer and a polarizing plate protective film formed on both surfaces of the second polarizer,
In the in-plane direction of the phase difference layer of the phase difference body arranged on one or both, the refractive indexes in the x and y directions orthogonal to each other are nx and ny, and the thickness direction in the phase difference layer is the z direction. Is defined as nz, the following general formula (I):
nx ≧ ny> nz (I)
And satisfying
When the in- plane retardation in the non-driven state of the vertical alignment type liquid crystal cell is defined as Re (Cell) and the in-plane retardation of the phase difference body disposed on the one or both is defined as Re (C), General formula (II):
Re (Cell)> Re (C) (II)
Vertical alignment type liquid crystal display device satisfying When the in- plane retardation in the non-driven state of the vertical alignment type liquid crystal cell is defined as Re (Cell) and the in-plane retardation of the phase difference body disposed on the one or both is defined as Re (C), General formula (III):
0.01 <Re (C) / Re (Cell) <1 (III)
The liquid crystal display device according to claim 1, wherein: The phase difference body arranged on the one or both comprises a light-transmitting substrate and a phase difference layer,
The vertical according to claim 1 or 2 , wherein the retardation layer comprises a rod-shaped compound having refractive index anisotropy, and the rod-shaped compound forms a random homogeneous orientation in the retardation layer. Alignment type liquid crystal display device. The absolute value of Re (C) is 5nm or less, the vertical alignment type liquid crystal display device according to any one of claims 1-3. In the X-ray diffraction chart in the reflection method, when the surface of the retardation layer has an angle formed by an extension line of incident X-rays and reflected X-rays (2θ),
The ratio I _8.5 / I _17.0 between the intensity I _8.5 at an angle (2θ) of _8.5 ° and the intensity I ₁₇ at an angle (2θ) of 17.0 ° is 1.60 or less. Item 5. The vertical alignment type liquid crystal display device according to any one of items 1 to 4 . The ratio I _13.2 / I _14.8 between the intensity I _13.2 at an angle (2θ) of _13.2 ° and the intensity I ₁₇ at an angle (2θ) of 14.8 ° is 1.10 or less. Item 6. The vertical alignment type liquid crystal display device according to any one of items 1 to 5 .

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