JP2008076706A - Liquid crystal panel and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel, wherein the uniformity of the viewing angle in both vertical and horizontal directions is high and the cost related to the polarizer is low. <P>SOLUTION: The liquid crystal panel 100 has a first polarizer 21, a second polarizer 22 and a liquid crystal cell 10, wherein the liquid crystal cell 10 comprises liquid crystal molecules in a twisted nematic alignment; the first polarizer 21 is disposed on the display surface side of the liquid crystal cell 10, and the second polarizer 22 is disposed on the rear side of the liquid crystal cell 10. Furthermore, the liquid crystal panel 100 is characterized in that it has a first O plate 31, a second O plate 32, a first optical compensation layer 41, and a second optical compensation layer 42; the liquid crystal cell 10 has a rectangular shaped surface, and the first polarizer 21 and the second polarizer 22 are disposed in such a way that their absorption axes are nearly parallel or perpendicular to an edge of the rectangle of the surface shape of the liquid crystal cell 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal panel and a liquid crystal display device.

  Since the liquid crystal panel has features such as thinness, light weight, and low power consumption, it is widely used for flat panel displays such as personal computers, word processors or car navigation systems. In the liquid crystal panel, a gap having a predetermined interval is provided between two flat glass plates having transparent electrodes by a spacer, and a liquid crystal material is injected into the gap, and the edges of the two flat glass plates are sealed. The basic configuration is that a polarizer is arranged on one surface (display surface) of two flat glass plates and a polarizer is also arranged on the other surface (back surface). . There are various modes of the liquid crystal panel, and among them, the TN (Twisted Nematic) mode is a basic mode and is widely used for personal computers, monitors, and the like. The polarizer is generally used in the form of a polarizing plate having a transparent protective film attached thereto.

  In a TN mode liquid crystal panel, when no voltage is applied, the liquid crystal molecules are twisted and aligned at approximately 90 °, and the two polarizers are arranged with their absorption axes being substantially orthogonal to each other. Thus, white display is performed. Here, in the liquid crystal panel, in order to ensure the uniformity of the viewing angle in the vertical and horizontal directions, the absorption axes of the two polarizers are set to approximately 45 ° and 135 ° with respect to the long side of the liquid crystal cell as a reference. It is generally done.

However, affixing the polarizer with the setting as described above has a problem in the manufacturing cost of the polarizer. That is, in the production of a polarizer, it is common to produce a polyvinyl alcohol film by a continuous process in which a polyvinyl alcohol film is dyed with iodine and uniaxially stretched, and then cut into a predetermined size. In this case, the absorption axis of the polarizer is in the stretching direction. For this reason, if the absorption axis of the polarizer is cut in a direction that is approximately 45 ° or 135 °, the yield is significantly reduced, resulting in an increase in manufacturing cost and, as a result, an increase in the cost of the liquid crystal panel. On the other hand, in order to improve the color blur phenomenon of the polarizing plate caused by various inspections of the liquid crystal panel in a high temperature environment, it is manufactured by cutting so that the absorption axis is approximately 0 ° or 90 ° with respect to the long side of the polarizing plate. It has been proposed to use a polarizing plate (for example, see Patent Document 1). In such a polarizing plate, the stretching direction (absorption axis direction) coincides with the cutting direction, so that the yield is improved. However, the use of a polarizing plate that is cut so that the absorption axis is substantially 0 ° or 90 ° with respect to the long side of the polarizing plate does not improve the uniformity of the viewing angle of the liquid crystal panel.
Japanese Patent Laid-Open No. 8-136731

  SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal panel having a high viewing angle uniformity, a low cost for a polarizer, and a liquid crystal display device using the same.

In order to achieve the above object, a liquid crystal panel of the present invention includes a first polarizer, a second polarizer, and a liquid crystal cell, and the liquid crystal cell is a liquid crystal cell in which liquid crystal molecules are twisted nematically aligned. A liquid crystal panel in which the first polarizer is disposed on the display surface side of the liquid crystal cell, and the second polarizer is disposed on the back surface side of the liquid crystal cell; It has an O plate, a second O plate, a first optical compensation layer, and a second optical compensation layer, and the first optical compensation layer and the second optical compensation layer have the relationship of the following formula (1): And the surface shape of the liquid crystal cell is rectangular, and the first polarizer and the second polarizer have a relationship in which the absorption axis is parallel or orthogonal to the rectangular side of the surface shape of the liquid crystal cell. Are arranged.

nx> ny ≧ nz (1)

In the formula (1), nx is the maximum refractive index in the plane direction of the optical compensation layer (refractive index in the slow axis direction), and ny is the direction of the nx in the plane direction of the optical compensation layer. Is the refractive index in the direction orthogonal to the fast axis direction (refractive index in the fast axis direction), and nz is the refractive index in the thickness direction of the optical compensation layer orthogonal to the nx and ny directions.

  The liquid crystal display device of the present invention is a liquid crystal display device including a liquid crystal panel, and the liquid crystal panel is the liquid crystal panel of the present invention.

  As described above, in the liquid crystal panel of the present invention, by using the O plate and the optical compensation layer, high uniformity in the vertical and horizontal directions of the viewing angle is maintained, and both the polarizers have absorption axes. The liquid crystal cell can be arranged in a parallel or orthogonal relationship with respect to the rectangular side of the liquid crystal cell. For this reason, a polarizer with a high yield that is cut so that the absorption axis is parallel or orthogonal to the stretching direction at the time of manufacture can be used as both the polarizers, and the cost of the liquid crystal panel is also advantageous. . Therefore, the liquid crystal display device using the liquid crystal panel of the present invention is excellent in cost and excellent in the uniformity of the viewing angle in the vertical and horizontal directions.

  In the liquid crystal panel of the present invention, the first optical compensation layer and the first O plate are arranged in this order from the liquid crystal cell side between the first polarizer and the liquid crystal cell. It is preferable that the second optical compensation layer and the second O plate are arranged in this order from the liquid crystal cell side between the second polarizer and the liquid crystal cell.

  In the liquid crystal panel of the present invention, the first optical compensation layer and the second optical compensation layer may be biaxial retardation layers. In the liquid crystal panel of the present invention, the first optical compensation layer and the second optical compensation layer may be A plates. The biaxial retardation layer satisfies a refractive index relationship of nx> ny> nz, and the A plate satisfies a refractive index relationship of nx> ny = nz. The nx, ny and nz are the same as defined in the formula (1).

  The liquid crystal panel of the present invention further includes a negative C plate, the first optical compensation layer and the second optical compensation layer are A plates, and the first polarizer and the liquid crystal cell Between the liquid crystal cell side, the first optical compensation layer, the first O plate, and the negative C plate are arranged in this order, and between the second polarizer and the liquid crystal cell. It is also preferable that the second optical compensation layer and the second O plate are arranged in this order from the liquid crystal cell side.

  In the liquid crystal panel of the present invention, it is preferable that the absorption axis of the first polarizer and the slow axis of the first O plate are parallel, and the absorption axis of the first polarizer and the first optical element are the same. The slow axis of the compensation layer is preferably orthogonal, the absorption axis of the second polarizer and the slow axis of the second O plate are preferably parallel, It is preferable that the absorption axis and the slow axis of the second optical compensation layer are orthogonal to each other.

  In the liquid crystal panel of the present invention, it is preferable that the first polarizer and the second polarizer are arranged so that their absorption axes are orthogonal to each other.

  In the present invention, “orthogonal” includes a case of being substantially orthogonal, and the case of being substantially orthogonal is, for example, a range of 90 ° ± 1 °, preferably 90 ° ± The range is 0.5 °. In the present invention, “parallel” includes a substantially parallel case, and the substantially parallel case is, for example, in the range of 0 ° ± 1 °, preferably 0 ° ± 0.5 °. Range. In the present invention, the angle of each constituent member refers to an angle in a counterclockwise direction with the long side direction as a reference (0 °) when the planar shape of the liquid crystal cell is rectangular, for example.

  In the liquid crystal panel of the present invention, the liquid crystal cell is not particularly limited, but a TN mode liquid crystal cell is preferable.

  In the liquid crystal panel of the present invention, the reason is unknown, but the first polarizer is manufactured by cutting so that the absorption axis of the first polarizer is approximately 0 ° or 90 ° with respect to the absorption axis of the second polarizer. Even when the polarizing plate is adopted, it is possible to ensure the uniformity of the viewing angle in the vertical and horizontal directions.

  The present invention will be described in detail below.

[A. Liquid crystal panel of the present invention]
1 and 2 show an example of the liquid crystal panel of the present invention. FIG. 1 is a cross-sectional view showing the configuration of the liquid crystal panel of this example, and FIG. 2 is an exploded perspective view showing the configuration of the liquid crystal panel of this example. In both the drawings, in order to make the configuration of the liquid crystal panel of the present invention easier to understand, the size and ratio of each component are different from the actual ones, and the other configuration diagrams (FIGS. 3, 4, and 9). The same applies to FIG. 10). Moreover, in the said both figures, the same code | symbol is attached | subjected to the same part. As shown in both the drawings, the liquid crystal panel 100 of this example includes a liquid crystal cell 10, a first polarizer 21, a second polarizer 22, a first O plate 31, a second O plate 32, a first The biaxial retardation layer 41 and the second biaxial retardation layer 42 are used as main constituent members. The liquid crystal cell 10 has a configuration in which a liquid crystal layer 13 is disposed in a gap between a first substrate 11 and a second substrate 12. In the liquid crystal panel 100 of the present example, the first biaxial retardation layer 41 and the first O plate are disposed between the liquid crystal cell 10 and the first polarizer 21 from the liquid crystal cell 10 side. 31 are arranged in this order, and the second biaxial retardation layer 42 and the second O are disposed between the liquid crystal cell 10 and the second polarizer 22 from the liquid crystal cell 10 side. Plates 32 are arranged in this order. In the liquid crystal panel 100 of this example, the first polarizer 21 side is the display side, and the second polarizer 22 side is the back side. The first polarizer 21 and the second polarizer 22 are arranged so that their absorption axes are substantially orthogonal to each other. Further, each of the first polarizer 21 and the second polarizer 22 has an absorption axis that is parallel or orthogonal to the rectangular side of the planar shape of the liquid crystal cell 10 (long side in the case of a rectangle). It is arranged to be. Accordingly, in the first polarizer 21 and the second polarizer 22, their absorption axes 3 and 4 are parallel or orthogonal to the sides of the polarizer. In the present example, the first and second optical compensation layers are biaxial retardation layers. However, the present invention is not limited to this, and may be an A plate. In the present invention, the planar shape of the liquid crystal cell is a rectangle, may be a square, or may be a rectangle, but is preferably a rectangle. In the present invention, the shape of each constituent member such as the polarizer, the optical compensation layer, and the O plate is preferably rectangular, may be square, may be rectangular, Preferably, it is a rectangle that matches the planar shape of the liquid crystal cell.

  FIG. 3 shows another example of the liquid crystal panel of the present invention. FIG. 3 is a cross-sectional view showing the configuration of the liquid crystal panel of this example. In FIG. 3, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. As shown in FIG. 3, the liquid crystal panel 101 of this example includes a liquid crystal cell 10, a first polarizer 21, a second polarizer 22, a first A plate 43, a second A plate 44, and a first An O plate 31, a second O plate 32, and a negative C plate 51 are provided as main constituent members. The liquid crystal cell 10 has a configuration in which a liquid crystal layer 13 is disposed in a gap between a first substrate 11 and a second substrate 12. In the liquid crystal panel 101 of this example, the first A plate 43, the first O plate 31, and the negative electrode are arranged between the liquid crystal cell 10 and the first polarizer 21 from the liquid crystal cell 10 side. C plates 51 are arranged in this order, and the second A plate 44 and the second O plate 32 are arranged between the liquid crystal cell 10 and the second polarizer 22 from the liquid crystal cell 10 side. Are arranged in this order. In the liquid crystal panel 101 of this example, the first polarizer 21 side is the display side, and the second polarizer 22 side is the back side. The first polarizer 21 and the second polarizer 22 are arranged so that their absorption axes are orthogonal to each other. In addition, the first polarizer 21 and the second polarizer 22 are arranged such that each absorption axis is parallel or orthogonal to the rectangular side of the planar shape of the liquid crystal cell 10. Therefore, in the first polarizer 21 and the second polarizer 22, their respective absorption axes are parallel or orthogonal to the sides of the polarizer.

  In the liquid crystal panel of the present invention, a protective layer or a surface treatment layer may be provided on the surface (the surface opposite to the liquid crystal cell side) of at least one of the first polarizer and the second polarizer. Good. An adhesive layer may be provided between the constituent members of the liquid crystal panel. The “adhesive layer” refers to a layer that joins surfaces with adjacent members and integrates them with practically sufficient adhesive force and adhesion time. Examples of the material for forming the adhesive layer include an adhesive, a pressure-sensitive adhesive, and an anchor coat agent. The adhesive layer may have a multilayer structure in which an anchor coating agent is formed on the surface of an adherend and an adhesive layer or a pressure-sensitive adhesive layer is formed thereon. The adhesive layer may be a thin layer (also referred to as a hairline) that cannot be recognized with the naked eye.

  In the liquid crystal display device using the liquid crystal panel of the present invention, when a black image is displayed on the display screen, light leakage from the backlight can be prevented in the front and oblique directions. As a result, the contrast ratio in the oblique direction can be increased, and in particular, a display image with high uniformity of the viewing angle in the vertical and horizontal directions can be obtained.

[B. Liquid crystal cell)
As shown in FIGS. 1, 2, and 3, a liquid crystal cell 10 used in the present invention includes a liquid crystal layer 13, a first substrate 11 disposed on the first polarizer 21 side of the liquid crystal layer 13, And the second substrate 12 disposed on the second polarizer 22 side of the liquid crystal layer 13. One of the substrates 11 and 12 (active matrix substrate) is preferably provided with a scanning line for providing electro-optical characteristics of liquid crystal and a signal line for supplying a source signal (not shown). The other substrate (color filter substrate) is provided with a color filter. Note that the color filter may be provided on the active matrix substrate. Or, for example, when a RGB three-color light source (which may include a multicolor light source) is used as the illumination means of the liquid crystal display device as in the field sequential method, the color filter is omitted. Also good. A distance (cell gap) between the two substrates is formed by a spacer (not shown).

  Each of the first substrate and the second substrate preferably has an alignment film subjected to alignment treatment on the liquid crystal layer 13 side. The alignment treatment is not particularly limited as long as it is a treatment for bringing liquid crystal molecules into a certain alignment state on the surface of the substrate, and any method can be adopted. As the alignment treatment, it is preferable to use a rubbing method in which a polymer such as polyimide is applied to form a thin film, and the thin film is rubbed in one direction with a fiber such as nylon or polyester. For example, when the rubbing method is used as the alignment treatment, the alignment treatment direction is the rubbing direction. In FIG. 2, 1 indicates the rubbing direction of the first substrate 11, and 2 indicates the rubbing direction of the second substrate 12.

  The liquid crystal layer 13 is preferably aligned in a twisted arrangement in the absence of an electric field. In general, the twist alignment is such that the liquid crystal molecules in the liquid crystal layer are aligned substantially parallel to both substrate surfaces, and the alignment direction is twisted by 90 ° on both substrate surfaces. A liquid crystal cell having such a liquid crystal layer in an aligned state is typically a twisted nematic (TN) mode liquid crystal cell.

[C. Polarizer]
In the present invention, “polarizer” refers to an element capable of converting natural light or polarized light into arbitrary polarized light. The polarizer used in the present invention is not particularly limited, but is preferably one that converts natural light or polarized light into linearly polarized light. Such a polarizer has a function of transmitting one polarized light component when incident light is divided into two orthogonal polarized light components, and absorbing, reflecting, and scattering the other polarized light component. Etc. are not allowed to pass through.

  As the first and second polarizers used in the present invention, any appropriate one can be selected as long as the object of the present invention can be achieved. For example, a polarizer produced by a continuous process in which a polyvinyl alcohol film is dyed with iodine and uniaxially stretched and then cut into a predetermined size can be used. The first and second polarizers may be the same or different. For example, each of the polarizers may be a single layer or a multilayer polarizing film, or a laminate including a base material and a polarizing film, or two or more base materials for a polarizing film. A sandwich (so-called polarizing plate) may be used via an adhesive layer. The thickness of each polarizer is usually in the range of 5 to 100 μm. As each of the polarizers, a commercially available polarizing plate can be used as it is. Examples of commercially available polarizing plates include the product name “NPF SEG1224DU” manufactured by Nitto Denko Corporation and the product name “NPF SIG1423DU” manufactured by the same company.

  The relationship between the absorption axis of the first polarizer and the absorption axis of the second polarizer is orthogonal depending on whether the liquid crystal display device used is a normally white system or a normally black system. Or parallel can be selected. The absorption axis of the first polarizer is preferably orthogonal to the absorption axis of the second polarizer, that is, a normally white system is preferable. In FIG. 2, 3 indicates an absorption axis of the first polarizer 21, and 4 indicates an absorption axis of the second polarizer 22.

  The first polarizer and the second polarizer are arranged such that each absorption axis is parallel or orthogonal to a rectangular side of the planar shape of the liquid crystal cell. Therefore, in the first polarizer and the second polarizer, their absorption axes are parallel or orthogonal to the rectangular sides of the polarizer.

  The first polarizer and the second polarizer preferably have a transmittance at a wavelength of 590 nm (also referred to as a single transmittance) of 41% or more and a degree of polarization at a wavelength of 590 nm of 99.8% or more. The theoretical upper limit is 50% for the single transmittance and 100% for the degree of polarization. A liquid crystal display device having a high contrast ratio in the front direction can be obtained by setting the single transmittance and the degree of polarization to the above-described conditions.

[D. O plate]
In the present invention, the “O plate” refers to a retardation layer in which molecules are aligned in a tilted arrangement. The first O plate and the second O plate in the present invention are formed from a solidified layer or a hardened layer (that is, a retardation layer) of a rod-like liquid crystal compound aligned in a hybrid arrangement. FIG. 2 shows the alignment state of the rod-like liquid crystal compound 33 in the O plate. In the figure, 7 is an arrow indicating the director direction. The tilt angle (θ _P ) on the polarizer side of the rod-like liquid crystal compound is larger than the tilt angle (θ _B ) on the liquid crystal cell side. Here, the tilt angle (θ) represents an angle formed with the surface of the O plate on the liquid crystal cell side, and is 0 ° when parallel to the surface.

  The first O plate and the second O plate may be the same or different. The thickness of both O plates is, for example, in the range of 0.1 to 10 μm, and preferably in the range of 0.5 to 5 μm.

  In the liquid crystal panel of the example shown in FIG. 1 and FIG. 2, the first O plate 31 is disposed between the first polarizer 21 and the first biaxial retardation layer 41, and The second O plate 32 is disposed between the second polarizer 22 and the second biaxial retardation layer 42. In the liquid crystal panel of the example shown in FIG. 3, the first O plate 31 is disposed between the first A plate 43 and the negative C plate 51, and the second O plate 32 is the first O plate 32. The second A plate 44 and the second polarizer 22 are disposed.

  The optical axis (slow axis) of the first O plate is preferably parallel to the absorption axis of the first polarizer. Similarly, the optical axis (slow axis) of the second O plate is preferably parallel to the absorption axis of the second polarizer. In the present invention, the “slow axis” refers to the direction in which the in-plane refractive index is maximum.

In the present invention, the “hybrid alignment” refers to a state in which the tilt angle (tilt angle) of the rod-like liquid crystal compound is increased or decreased continuously or intermittently in the thickness direction. The tilt angle (θ _P ) on the side and the tilt angle (θ _B ) on the biaxial retardation layer side are different.

As shown in the following formulas (I) and (II), the tilt angle of the rod-like liquid crystal compound at the interface adjacent to the other components of the O plate is Journal of Applied Phisics Vol. 38 (1999) p. The expression of Witte according to 748, premeasured _n e, _{n o,} and the phase difference value (in the slow axis direction parallel to the polar angle -40 ° ~ + 40 ° (the normal direction to 0 °) Each value measured in 5 ° increments) can be substituted. Here, θ _air represents the tilt angle on one side (eg, air interface) of the rod-like liquid crystal compound, and θ _AL represents the tilt angle on the other side (eg, substrate or alignment film) interface. d represents the thickness of the solidified layer or hardened layer of the rod-like liquid crystal compound aligned in a hybrid arrangement. n _e represents an extraordinary refractive index of the rod-like liquid crystal compound, n _o represents an ordinary refractive index of the rod-like liquid crystal compound.

The direction in which the director direction of the rod-like liquid crystal compound is projected onto the liquid crystal cell surface (also referred to as the alignment direction) is preferably substantially the same as the alignment treatment direction of the liquid crystal cell. In the present invention, the “director direction” means the orientation direction of the entire liquid crystal molecules as viewed statistically, and is also referred to as an average tilt angle (θ _ave. = (Θ _P + θ _B ) / 2). Here, the θ _ave. Represents an angle formed with the biaxial retardation layer surface, and 0 ° when parallel to the surface. The orientation direction is substantially parallel to the slow axis of the O plate.

The average inclination angle (θ _ave. ) Is, for example, in the range of 5 ° to 50 °. By setting the average tilt angle within the above range, more appropriate optical compensation of the liquid crystal cell is performed, and a liquid crystal display device having a high contrast ratio in the oblique direction can be obtained. The average inclination angle is preferably in the range of 10 ° to 45 °, and more preferably in the range of 20 ° to 40 °.

  The transmittance (T [590]) at a wavelength of 590 nm of at least one of the first O plate and the second O plate is, for example, 85% or more, and preferably 90% or more.

  The in-plane retardation value (Re [590]) at a wavelength of 590 nm of at least one of the first O plate and the second O plate is obtained when black is displayed when the liquid crystal display device is a normally white system ( An appropriate value is preferably set as appropriate so as to be substantially equal to the phase difference value of the liquid crystal cell at the time of voltage application. Re [590] of at least one of the first O plate and the second O plate is, for example, in the range of 50 nm to 200 nm. By setting the in-plane retardation value within the above range, more appropriate optical compensation of the liquid crystal cell is performed, and a liquid crystal display device having a high contrast ratio in an oblique direction can be obtained. The in-plane retardation value is preferably in the range of 70 nm to 180 nm, more preferably in the range of 90 nm to 160 nm. In the present invention, the in-plane retardation value (Re [λ]) refers to, for example, an in-plane retardation value at a wavelength λ (nm) at 23 ° C. Re [λ] can be obtained by Re [λ] = (nx−ny) × d, where d (nm) is the thickness of the film.

  In the present invention, the “rod-like liquid crystal compound” has a mesogenic group in its molecular structure, and the refractive index in the major axis direction of the mesogenic group is larger than the refractive index in the minor axis direction of the same group. A compound that exhibits a liquid crystal phase by temperature change such as heating and cooling, or by the action of a certain amount of solvent. In the present invention, the “solidified layer” means a softened, melted or solution-state liquid crystalline composition that has been cooled and solidified, and the “cured layer” is a part or all of the liquid crystalline composition, A product that has been cross-linked or polymerized by at least one of heat, catalyst, light, and radiation to be insoluble or insoluble or hardly soluble.

  Any appropriate rod-like liquid crystal compound can be selected. Preferably, the rod-like liquid crystal compound exhibits a crystal or glass state at a low temperature and develops a nematic liquid crystal phase at a high temperature. The rod-shaped liquid crystal compound exhibits a liquid crystal phase before film formation, but after film formation, for example, a network structure may be formed by a crosslinking reaction and no liquid crystal phase may be exhibited. If the rod-like liquid crystal compound having the above properties is used, for example, after forming a hybrid arrangement in a state showing a liquid crystal phase, the arrangement state can be fixed by cooling or crosslinking.

  The mesogenic group is a structural part necessary for forming a liquid crystal phase and usually contains a cyclic unit. Examples of the mesogen group include a biphenyl group, a phenylbenzoate group, a phenylcyclohexane group, an azoxybenzene group, an azomethine group, an azobenzene group, a phenylpyrimidine group, a diphenylacetylene group, a diphenylbenzoate group, a bicyclohexane group, a cyclohexylbenzene group, A terphenyl group etc. are mentioned. In addition, the terminal of these cyclic units may have substituents, such as a cyano group, an alkyl group, an alkoxy group, a halogen group, for example. Especially, as a mesogenic group which consists of a cyclic unit etc., what has a biphenyl group and a phenylbenzoate group is preferable.

  The rod-like liquid crystal compound may be a polymer substance (polymer liquid crystal) having a mesogen group in at least one of a main chain and a side chain, or a low molecular substance (low molecule having a mesogen group in a part of the molecular structure. Liquid crystal). Since the polymer liquid crystal can be cooled from the liquid crystal state and the molecular orientation state can be fixed, it has a feature of high film forming productivity. Since the low-molecular liquid crystal is excellent in orientation, it has a feature that a highly transparent retardation layer is easily obtained.

  The rod-like liquid crystal compound preferably has at least one crosslinkable functional group in a part of the molecular structure. This is because the cross-linking reaction increases the mechanical strength and provides a retardation layer having excellent durability. Examples of the crosslinkable functional group include an acryloyl group, a methacryloyl group, an epoxy group, and a vinyl ether group. As the rod-like liquid crystal compound, a commercially available product can be used as it is, or it can be synthesized in-house and used. Arbitrary additives, such as another liquid crystal compound, a polymerization initiator, and a leveling agent, may be added to a commercially available product or a self-synthesized rod-like liquid crystal compound to be used as a liquid crystalline composition. Examples of commercial products of rod-shaped liquid crystal compounds having a crosslinkable functional group include BASF's trade name “Pariocolor LC242”, HUNTSMAN's trade name “CB483”, and the like.

The manufacturing method of the O plate in which the rod-like liquid crystal compound is aligned in a hybrid arrangement is not particularly limited, and is manufactured by any appropriate alignment processing method. The O plate of the present invention can be produced, for example, by a production method including the following steps A _{1 to} E ₁ .

(A ₁ ) Step of preparing two substrates, applying one alignment treatment to one substrate, and applying a second alignment treatment to the other substrate (however, the first alignment treatment and the second alignment treatment) Are not identical)
(B ₁ ) Step of preparing a coating liquid containing a rod-like liquid crystal compound and a solvent (C ₁ ) Each of the two substrates is subjected to the alignment-treated side, and the coating liquid is injected between them (sandwich) (D ₁ ) Step of heating the laminate to a liquid crystal temperature range (E ₁ ) Step of cooling the laminate to a liquid crystal temperature range or lower In the step (A ₁ ), the first and _first steps The two alignment treatments are independently a vertical alignment treatment, a horizontal alignment treatment, or a tilt alignment treatment.

As another method for producing O-plate, there is a manufacturing method comprising the step A ₂ to E ₂ below.

(A ₂ ) Step of applying an alignment treatment to the substrate (B ₂ ) Step of preparing a coating solution containing a rod-like liquid crystal compound and a solvent (C ₂ ) Applying the coating solution to the alignment-treated surface of the substrate and Engineering, the step of forming a laminate (D ₂₎ wherein the substrate side of the coating liquid in a state in which the interface on the side opposite the contact with the air, the step of heating the laminate to the liquid crystal temperature range (E ₂ ) Step of cooling the laminate to the liquid crystal temperature range or lower In the step (A ₂ ), the alignment treatment is vertical alignment treatment, horizontal alignment treatment, or tilt alignment treatment. Which of these treatments is selected can be appropriately determined according to the type and chemical properties of the rod-shaped liquid crystal compound to be used.

In the present invention, the tilt angle (θ _P ) on the polarizer side of the rod-like liquid crystal compound and the tilt angle (θ _B ) on the biaxial retardation layer side of the first and second O plates are, for example, Depending on the conditions of A _{1 to} E ₁ or steps A _{2 to} E ₂ and the type of the rod-like liquid crystal compound or the composition containing the same, it can be increased or decreased as appropriate.

  As the alignment treatment method, an appropriate method can be adopted as appropriate. The alignment treatment method is, for example, (A) a method in which an alignment agent is adsorbed on the surface of a substrate to form an alignment agent layer (also referred to as alignment film), and (B) the substrate or the substrate is formed. Examples include a method of changing the surface of the alignment film in shape, and (C) a method of irradiating light on the substrate or the surface of the alignment film formed on the substrate (also referred to as a photo-alignment method). Of these, the photo-alignment method is preferable as the alignment treatment method. Since the photo-alignment method is a process that generates very little static electricity, dust, dust, etc., it is possible to produce a phase-difference layer with excellent quality, and the phase-difference layer depends on the direction and direction of light irradiation. It is characterized in that the tilt angle and slow axis direction of the rod-like liquid crystal compound in the inside can be controlled arbitrarily in the plane.

  The alignment agent for the vertical alignment treatment is not particularly limited, and for example, lecithin, versamide 100, octadecylmalonic acid, organic silane, tetrafluoroethylene, polyimide, stearic acid and the like are used. The alignment agent for the horizontal alignment treatment is not particularly limited, and examples thereof include carbon, polyoxyethylene, versamide 125, polyvinyl alcohol, polyimide, dibasic carboxylic acid chromium complex, organic silane, acetylene, and dibasic fatty acid. , Crown ether and the like are used.

  The alignment agent for the photo-alignment method (the formed film is also referred to as a photo-alignment film) preferably contains a compound having at least one photoreactive functional group in the molecular structure. Such alignment agents include, for example, those containing a compound having a photoreactive functional group that generates a photochemical reaction such as a photoisomerization reaction, a photo-opening / closing ring reaction, a photo-dimerization reaction, a photolysis reaction, a photo-fleece transition reaction, etc. It is done. Examples of the photoreactive functional group that causes a photoisomerization reaction include an azobenzene group, a stilbene group, an α-hydrazono-β-ketoester group, a cinnamate group, a benzylidenephthalimidine group, and retinoic acid. Examples of the photoreactive functional group that causes a photodimerization reaction include a cinnamate group, a benzylidenephthalimidine group, a chalcone group, a coumarin group, a styrylpyridine group, and an anthracene group.

As a condition for irradiating the surface of the photo-alignment film with light, an appropriate method is appropriately selected according to the type of photochemical reaction of the compound having a photoreactive functional group used for the photo-alignment film. Examples of the light source used for light irradiation include an ultrahigh pressure mercury lamp, a flash UV lamp, a high pressure mercury lamp, a low pressure mercury lamp, a deep UV lamp, a xenon lamp, and a metal halide lamp. The wavelength of the light source is preferably 210 nm to 380 nm. Further, the irradiation light amount of the light, as measured at a wavelength of 365 nm, preferably in ^the range of ^{5mJ / cm 2 ~500mJ / cm 2} . The wavelength of the light source is preferably used by cutting a region of 100 nm to 200 nm with a filter or the like in order to suppress the photodecomposition reaction of the photo-alignment film. If it is the said conditions, a rod-shaped liquid crystal compound can be uniformly aligned in a hybrid arrangement.

  Any appropriate method can be adopted as a method of preparing the coating liquid containing the rod-like liquid crystal compound and the solvent. Here, the “coating liquid” represents a solution or a dispersion. Examples of the solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 2-hexanone, diethyl ether, tetrahydrofuran, dioxane, anisole, ethyl acetate, butyl acetate, toluene, xylene, chloroform, and dichloromethane. Dichloroethane, dimethylformamide, dimethylacetamide, methyl cellosolve and the like. These solvents can be used alone or in admixture of two or more. The concentration of the rod-like liquid crystal compound in the coating solution is preferably 5% by weight to 40% by weight.

  As the coating method of the coating liquid, a coating method using an appropriate coater can be adopted as appropriate. Examples of the coater include a reverse roll coater, a forward rotation roll coater, a gravure coater, a knife coater, a rod coater, a slot die coater, a slot orifice coater, a curtain coater, a fountain coater, an air doctor coater, a kiss coater, a dip coater, a bead coater, and a blade coater. Cast coater, spray coater, spin coater, extrusion coater, hot melt coater and the like. The coater is preferably a reverse roll coater, a forward rotation roll coater, a gravure coater, a rod coater, a slot die coater, a slot orifice coater, a curtain coater, and a fountain coater. The coater preferably uses a coater head using a closed applicator in order to prevent a change in the concentration of the coating liquid. If it is the coating system using the said coater, a solidified layer or a hardened layer with small thickness variation can be obtained.

Any appropriate method can be adopted as a method of forming the solidified layer (O plate) of the rod-like liquid crystal compound aligned in the hybrid arrangement. Examples of the method for forming the solidified layer (O plate) include a method including the steps A _{1 to} E ₁ and a method including the steps A _{2 to} E ₂ . Prior to the formation of the solidified layer, the coating film formed by applying the coating liquid is preferably heat-dried. The drying temperature is preferably 30 ° C. or higher and a liquid crystal phase-isotropic phase transition temperature (Ti) or lower, and more preferably 30 ° C. to 120 ° C. Examples of the heating and drying means include an air circulation type constant temperature oven in which hot air or cold air circulates, a heater using microwaves or far infrared rays, a roll heated for temperature control, a heat pipe roll, or a metal belt. The heating method and temperature control method used are mentioned. The time for drying by heating (drying time) is usually 1 minute to 20 minutes. The isotropic phase transition temperature (Ti) can be determined by observing a sample of the rod-like liquid crystal compound or a liquid crystalline composition containing the rod-like liquid crystal compound with a polarizing microscope.

  Any appropriate method can be selected as a method for forming the hardened layer (O plate) of the rod-like liquid crystal compound aligned in the hybrid arrangement. Preferably, the cured layer is formed by using a rod-shaped liquid crystal compound (also referred to as a crosslinkable rod-shaped liquid crystal compound) having at least one crosslinkable functional group in a part of the molecular structure, or a crosslinkable compound and a rod-shaped liquid crystal. This is a method in which the solidified layer is formed using a composition containing a compound (also referred to as a crosslinkable composition), and this is irradiated with ultraviolet rays for photocrosslinking. In this case, the time of irradiating the ultraviolet rays may be after the solidified layer is formed, but may be irradiated in the process of solidification.

As the conditions for curing the rod-like liquid crystal compound, any appropriate method is selected according to the type of photochemical reaction of the crosslinkable rod-like liquid crystal compound or the crosslinkable composition. The light source used for the light irradiation can be appropriately selected from those exemplified for the photo-alignment method. The wavelength of the light source is preferably 210 nm to 380 nm. Further, the irradiation light amount of the light, as measured at a wavelength of 365 nm, and ^{preferably, 30mJ / cm 2 ~1000mJ / cm} 2. In order to suppress the photodecomposition reaction of the photo-alignment film or the rod-like liquid crystal compound, it is preferable to use a wavelength of the light source by cutting a region of 100 nm to 200 nm with a filter or the like. Furthermore, it is preferable to replace the atmosphere around the crosslinkable rod-like liquid crystal compound or the crosslinkable composition irradiated with light with an inert gas such as nitrogen. If it is such conditions, the hardened layer excellent in thickness uniformity can be formed.

[E. (Biaxial retardation layer)
In this specification, the “biaxial retardation layer” means that the refractive index ellipsoid satisfies the relationship of nx>ny> nz. Such a biaxial retardation layer satisfies 10 nm <Re [590] <Rth [590].

  The first biaxial retardation layer and the second biaxial retardation layer may be the same or different from each other. The first biaxial retardation layer and the second biaxial retardation layer may be a single layer or a multilayer retardation layer, or a laminate including a base material and a retardation layer. There may be. Both the biaxial retardation layers may also serve as the O-plate base material described above. When the biaxial retardation layer also serves as a base material for the O plate, one surface of the biaxial retardation layer may be subjected to an alignment treatment in order to align the rod-like liquid crystal compound. Alternatively, an alignment film may be included. The thickness of the first biaxial retardation layer and the second biaxial retardation layer is, for example, in the range of 0.5 μm to 100 μm, and preferably in the range of 0.5 μm to 50 μm.

  In the liquid crystal panel 100 of the example shown in FIG. 1 and FIG. 2, the first biaxial retardation layer 41 is disposed between the first O plate 31 and the first substrate 11, and the second biaxial The phase difference layer 42 is disposed between the second O plate 32 and the second substrate 12. As shown in FIG. 2, the slow axis 5 of the first biaxial retardation layer 41 is preferably substantially orthogonal to the absorption axis 3 of the first polarizer 21, and the second biaxial property It is preferable that the slow axis 6 of the retardation layer 42 is substantially orthogonal to the absorption axis 4 of the second polarizer 22. The slow axis 5 of the first biaxial retardation layer 41 is preferably substantially orthogonal to the slow axis 6 of the second biaxial retardation layer 42. The slow axis 5 of the first biaxial retardation layer 41 is preferably substantially orthogonal to the rubbing direction 1 of the first substrate 11, and the slow axis of the second biaxial retardation layer 41 is 6 is preferably substantially orthogonal to the rubbing direction 2 of the second substrate 12. By disposing the constituent members in such an optical axis relationship, more appropriate optical compensation of the liquid crystal cell is performed, and a liquid crystal display device having a high contrast ratio in an oblique direction can be obtained.

  The transmittance (T [590]) at a wavelength of 590 nm of at least one of the first biaxial retardation layer and the second biaxial retardation layer is, for example, 85% or more, and more preferably 90%. % Or more.

  The in-plane retardation value (Re [590]) at a wavelength of 590 nm of at least one of the first biaxial retardation layer and the second biaxial retardation layer is, for example, in the range of 50 nm to 200 nm. Yes, preferably in the range of 80 nm to 180 nm, more preferably in the range of 100 nm to 160 nm.

Wherein the first biaxial retardation layer Re [590] _B1, the difference between the first O-plate of _{Re [590] O1 (Re [} 590] B1 -Re [590] O1) , for example, The difference between Re [590] _B2 of the second biaxial retardation layer and Re [590] _O2 of the second O plate (Re [590] _B2 -Re [ 590] _O2 ) is, for example, in the range of 0 nm to 60 nm. By setting the in-plane retardation value within the above range, more appropriate optical compensation of the liquid crystal cell is performed, and a liquid crystal display device having a high contrast ratio in an oblique direction can be obtained. And the first biaxial retardation layer Re [590] _B1, the difference between the first O-plate of _{Re [590] O1 (Re [} 590] B1 -Re [590] O1) is preferably The difference between Re [590] _B2 of the second biaxial retardation layer and Re [590] _O2 of the second O plate (Re [590] _B2 -Re [ 590] _O2 ) is preferably in the range of 10 nm to 50 nm.

  The retardation value (Rth [590]) in the thickness direction at a wavelength of 590 nm of at least one of the first biaxial retardation layer and the second biaxial retardation layer is such that the refractive index ellipsoid is nx> ny. > Nz satisfying the relationship of nz, for example, in the range of 80 nm to 360 nm, and by setting the retardation value in the thickness direction to the above range, more appropriate optical compensation of the liquid crystal cell is performed, and the oblique direction A liquid crystal display device with a high contrast ratio can be obtained. The thickness direction retardation value (Rth [590]) is preferably in the range of 100 nm to 320 nm, more preferably in the range of 120 nm to 280 nm. In the present invention, the thickness direction retardation value (Rth [λ]) refers to the thickness direction retardation value at a wavelength λ (nm) at 23 ° C., for example. Rth [λ] can be obtained by Rth [λ] = (nx−nz) × d, where d (nm) is the thickness of the film.

  The Nz coefficient of at least one of the first biaxial retardation layer and the second biaxial retardation layer is, for example, in the range of more than 1 and 6.0 or less. By setting the Nz coefficient within the above range, more appropriate optical compensation of the liquid crystal cell is performed, and a liquid crystal display device having a high contrast ratio in the oblique direction can be obtained. The Nz coefficient is preferably in the range of greater than 1 to 4.0 or less, and particularly preferably in the range of greater than 1 to 2.0 or less. The Nz coefficient is obtained by, for example, the formula: Rth [590] / Re [590].

  Any appropriate material can be selected as a material for forming the first biaxial retardation layer and the second biaxial retardation layer as long as the material satisfies the optical characteristics. Preferably, the first biaxial retardation layer and the second biaxial retardation layer include a retardation film containing a thermoplastic resin. The thermoplastic resin is not particularly limited. For example, norbornene resin, cellulose resin, polyamide resin, polycarbonate resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polyarylate Resin, polyamideimide resin, polyimide resin, acrylic resin and the like. These thermoplastic resins can be used alone or in combination of two or more.

  It is preferable that the first biaxial retardation layer and the second biaxial retardation layer include a retardation film containing a norbornene resin. In the present invention, the “norbornene resin” refers to a (co) polymer obtained by using a norbornene monomer having a norbornene ring as a part or all of a starting material (monomer). The “(co) polymer” represents a homopolymer or a copolymer (copolymer). The retardation film is produced, for example, by stretching a polymer film formed into a sheet shape.

As the norbornene-based resin, a norbornene-based monomer having a norbornene ring (having a double bond in the norbornane ring) is used as a starting material. In the (co) polymer state, the norbornene-based resin may or may not have a norbornane ring in the structural unit. The norbornene-based resin having a norbornane ring as a structural unit in the state of a (co) polymer is, for example, tetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] Dec-3-ene, 8-methyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] dec-3-ene, 8-methoxycarbonyltetracyclo [4.4.1 ^2,5 . 1 ^7,10 . 0] Dec-3-ene and the like. A norbornene-based resin having no norbornane ring as a structural unit in the (co) polymer state is, for example, a (co) polymer obtained using a monomer that becomes a 5-membered ring by cleavage. Examples of the monomer that becomes a 5-membered ring by cleavage include norbornene, dicyclopentadiene, 5-phenylnorbornene, and derivatives thereof. When the norbornene-based resin is a copolymer, the arrangement state of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer. It may be.

  Examples of the norbornene resin include (A) a resin obtained by hydrogenating a ring-opening (co) polymer of a norbornene monomer, and (B) a resin obtained by addition (co) polymerization of a norbornene monomer. The ring-opening copolymer of the norbornene monomer is a resin obtained by hydrogenating a ring-opening copolymer of at least one norbornene monomer and an α-olefin, cycloalkene, and / or non-conjugated diene. Include. The resin obtained by addition copolymerization of the norbornene monomer includes a resin obtained by addition copolymerization of one or more norbornene monomers with α-olefins, cycloalkenes and / or non-conjugated dienes.

  A resin obtained by hydrogenating a ring-opening (co) polymer of the norbornene-based monomer is subjected to a metathesis reaction of the norbornene-based monomer or the like to obtain a ring-opening (co) polymer. It can be obtained by hydrogenation. Specifically, for example, the method described in paragraphs [0059] to [0060] of JP-A-11-116780, the method described in paragraphs [0035] to [0037] of JP-A-2001-350017, and the like. Can be mentioned. The resin obtained by addition (co) polymerization of the norbornene monomer can be obtained, for example, by the method described in Example 1 of JP-A No. 61-292601. The descriptions in these publications constitute part of this specification. The same applies to the following.

  The weight average molecular weight (Mw) of the norbornene resin is preferably 20,000 to 500,000 as a value measured by a gel permeation chromatograph (GPC) method using a tetrahydrofuran solvent. The glass transition temperature (Tg) of the norbornene resin is preferably 120 ° C to 170 ° C. If it is resin with such a weight average molecular weight and glass transition temperature, it has the outstanding thermal stability and can obtain the polymer film which can control the in-plane and the thickness direction retardation value easily by extending | stretching. The glass transition temperature (Tg) is a value calculated by, for example, the DSC method according to JIS K7121.

  As a method for obtaining the polymer film containing the norbornene-based resin, any appropriate forming method can be adopted. Preferably, the molding method is a solvent casting method or a melt extrusion method. This is because a polymer film excellent in smoothness and optical uniformity can be obtained.

  The polymer film containing the norbornene-based resin may further contain any appropriate additive. Examples of the additive include a plasticizer, a heat stabilizer, a light stabilizer, a lubricant, an antioxidant, an ultraviolet absorber, a flame retardant, a colorant, an antistatic agent, a compatibilizer, a crosslinking agent, and a thickener. Is mentioned. The content of the additive is, for example, more than 0 and 10 parts by weight or less with respect to 100 parts by weight of the norbornene resin.

  As the polymer film containing the norbornene resin, a commercially available film can be used as it is. Alternatively, a commercially available film that has been subjected to secondary processing such as stretching or shrinking can be used. As a polymer film containing a commercially available norbornene resin, for example, Arton series (trade name; ARTON F, ARTON FX, ARTON D) manufactured by JSR Corporation, or ZEONOR series (trade name; ZEONOR Corporation) manufactured by Optes Co., Ltd. ZF14, ZEONOR ZF16) and the like.

  As a method for stretching the polymer film, any appropriate stretching method can be adopted depending on the purpose. Examples of the stretching method include a longitudinal uniaxial stretching method, a transverse uniaxial stretching method, a longitudinal and transverse simultaneous biaxial stretching method, and a longitudinal and transverse sequential biaxial stretching method. As a means for stretching the polymer film, any suitable stretching machine such as a roll stretching machine, a tenter stretching machine, and a biaxial stretching machine is used. The stretching machine preferably includes temperature control means. When stretching by heating, the internal temperature of the stretching machine may be changed continuously or stepwise. The stretching step may be performed once or may be performed by dividing into two or more times. The stretching direction may be the longitudinal direction (MD direction) of the film or the width direction (TD direction). Moreover, you may extend | stretch in the diagonal direction (diagonal extending | stretching) using the extending | stretching method of FIG. 1 of Unexamined-Japanese-Patent No. 2003-262721.

  The temperature at which the polymer film is stretched (stretching temperature) can be appropriately set according to the purpose. Preferably, the stretching is performed in the range of Tg + 1 ° C. to Tg + 30 ° C. with respect to the glass transition temperature (Tg) of the polymer film. By selecting such conditions, the retardation value is likely to be uniform, and the retardation film is less likely to be crystallized (white turbidity). The stretching temperature is preferably 100 ° C to 180 ° C, more preferably 120 ° C to 160 ° C. As the stretching temperature control means, for example, an air circulation type constant temperature oven in which hot air or cold air circulates, a heater using microwaves or far infrared rays, a roll heated for temperature control, a heat pipe roll, a metal belt, etc. Can be mentioned. The glass transition temperature can be determined by, for example, the DSC method according to JIS K 7121 (1987).

  The magnification (stretch ratio) for stretching the polymer film can be appropriately selected according to the target retardation value. The draw ratio is, for example, in the range of more than 1 and not more than 3 times, preferably in the range of more than 1 and not more than 2.5 times, more preferably in the range of more than 1 and not more than 2 times. Further, the feeding speed at the time of stretching is not particularly limited, but is preferably 0.5 m / min to 30 m / min in view of mechanical accuracy, stability and the like. Under such stretching conditions, a target retardation value can be obtained, and a retardation film excellent in uniformity can be obtained.

[F. A plate]
In the present invention, “A plate” means that the refractive index ellipsoid satisfies the relationship of nx> ny = nz. In the present invention, “ny = nz” includes not only the case where ny and nz are exactly equal, but also the case where they are substantially equal. Here, the case where ny and nz are substantially equal is, for example, a range of 0 ≦ ny−nz ≦ 0.01.

  The first A plate and the second A plate may be the same or different. The first A plate and the second A plate may be a single layer or a multilayer retardation layer, or may be a laminate including a base material and a retardation layer. Alternatively, both the A plates may also serve as the base material of the O plate described above. When the A plate also serves as the base material of the O plate, one surface of the A plate may be subjected to an alignment treatment to align the rod-like liquid crystal compound, or has an alignment film. May be. The thickness of the first A plate and the second A plate is, for example, 0.5 μm to 100 μm, preferably 0.5 μm to 50 μm.

[G. Negative C plate]
In the present invention, the “negative C plate” means that the refractive index ellipsoid satisfies the relationship of nx = ny> nz. In the present invention, “nx = ny” includes not only the case where nx and ny are exactly equal, but also the case where they are substantially equal. Therefore, the negative C plate may have an in-plane phase difference, or may have a slow axis. The in-plane retardation Re practically acceptable for the negative C plate is, for example, in the range of 0 to 20 nm, preferably in the range of 0 to 10 nm, and more preferably in the range of 0 to 5 nm.

  The thickness direction retardation Rth of the negative C plate is, for example, in the range of 30 to 300 nm, preferably in the range of 40 to 180 nm, and more preferably in the range of 50 to 120 nm. The thickness of the negative C plate having such a retardation in the thickness direction can vary depending on the material used. The thickness of the negative C plate is, for example, in the range of 0.5 to 150 μm, preferably in the range of 0.5 to 100 μm, and more preferably in the range of 0.5 to 80 μm. When the negative C plate is composed of a cholesteric alignment solidified layer described later alone, the thickness thereof is, for example, in the range of 0.5 to 10 μm, preferably in the range of 0.5 to 8 μm, more preferably It is in the range of 0.5-5 μm. Such a thickness is thinner than the thickness (for example, 60 μm or more) of the negative C plate by biaxial stretching, and can greatly contribute to the thinning of the image display device. Furthermore, heat unevenness can be remarkably prevented by forming the negative C plate very thin. Further, such a very thin optical compensation layer is preferable from the viewpoints of prevention of disorder of cholesteric alignment and reduction of transmittance, selective reflectivity, coloring prevention, productivity, and the like. The negative C plate in the present invention is formed of any appropriate material as long as the above thickness and optical characteristics can be obtained. Preferably, such a very thin negative C plate can be manufactured by forming a cholesteric alignment using a liquid crystal material and fixing the cholesteric alignment, that is, by forming a cholesteric alignment solidified layer.

[H. Liquid crystal display device)
The liquid crystal display device of the present invention includes the liquid crystal panel of the present invention. FIG. 4 shows an example of the configuration of the liquid crystal display device of the present invention. In the figure, the same parts as those in FIGS. 1 to 3 are denoted by the same reference numerals. Moreover, in the same figure, in order to make it intelligible, the size, ratio, etc. of each structural member differ from actual. As illustrated, the liquid crystal display device 200 of this example includes at least a liquid crystal panel 100 and a direct-type backlight unit 80 disposed on one side of the liquid crystal panel 100. The direct-type backlight unit 80 includes at least a light source 81, a reflection film 82, a diffusion plate 83, a prism sheet 84, and a brightness enhancement film 85. In the liquid crystal display device 200 of this example, the case where the direct type is adopted as the backlight unit 80 is shown, but the present invention is not limited to this, and for example, a sidelight type backlight unit is used. There may be. The sidelight-type backlight unit further includes at least a light guide plate and a light reflector in addition to the direct-type configuration. In addition, as long as the effect of the present invention is obtained, a part of the optical member illustrated in FIG. 4 can be omitted depending on the application, such as the illumination method of the liquid crystal display device and the driving mode of the liquid crystal cell, or Other optical members can be substituted.

  The liquid crystal display device may be a transmissive type in which the screen is viewed by irradiating light from the back of the liquid crystal panel, or a reflective type in which the screen is viewed by irradiating light from the viewing side of the liquid crystal panel. A semi-transmission type having both properties of a transmission type and a reflection type may be used.

  In the liquid crystal display device of the present invention, the average value of the contrast ratio at a polar angle of 40 ° and an azimuth angle of 0 ° to 360 ° is preferably 60 or more, and more preferably 70 to 150. Further, in the liquid crystal display device, the maximum value of the contrast ratio at a polar angle of 40 ° and an azimuth angle of 0 ° to 360 ° is preferably 160 or more, and more preferably 170 to 250. Further, in the liquid crystal display device, the minimum value of the contrast ratio at a polar angle of 40 ° and an azimuth angle of 0 ° to 360 ° is preferably 20 or more, and more preferably 25 to 55. The liquid crystal display device of the present invention exhibits display characteristics that are thus far superior to conventional liquid crystal display devices.

[I. Application of liquid crystal display device)
The liquid crystal display device of the present invention is used for any appropriate application. Applications include, for example, OA devices such as desktop personal computers, notebook personal computers, and copy machines, mobile phones, watches, digital cameras, personal digital assistants (PDAs), portable devices such as portable game machines, video cameras, televisions, microwave ovens, etc. Home appliances, back monitors, car navigation system monitors, car audio and other in-vehicle equipment, exhibition equipment such as commercial store information monitors, security equipment such as surveillance monitors, nursing care monitors, medical monitors, etc. Nursing care / medical equipment.

  The use of the liquid crystal display device of the present invention is preferably a television. The screen size of the television is, for example, a wide 17 type (373 mm × 224 mm) or more, preferably a wide 23 type (499 mm × 300 mm) or more, and more preferably a wide 32 type (687 mm × 412 mm) or more.

  Examples of the present invention will be described together with comparative examples. The present invention is not limited or restricted by the following examples and comparative examples. In addition, various properties and physical properties in each example and each comparative example were measured and evaluated by the following methods.

(1) Tilt angle at the interface of the rod-like liquid crystal compound The tilt angle at the interface of the rod-like liquid crystal compound was measured according to Journal of Applied Phisics Vol. 38 (1999) p. In Witt's equation described in 748, n _e , n _o , and phase difference value (in parallel with the slow axis, polar angle −40 ° to + 40 ° (normal direction is 0 °) in 5 ° increments) Each measured value) was substituted and determined. As the retardation value, a value measured at a wavelength of 590 nm and 23 ° C. using a spectroscopic ellipsometer [manufactured by JASCO Corporation, product name “M-220”] was used. Further, _{n e} and _{n o} was used a value measured using an Abbe refractometer Atago Co., Ltd. product name "DR-M4".

(2) Single transmittance of the polarizer The single transmittance of the polarizer is specified in JlS Z 8701-1982 using a spectrophotometer [product name “DOT-3” manufactured by Murakami Color Research Laboratory Co., Ltd.]. The Y value subjected to visibility correction was measured and obtained with a two-degree field of view (C light source).

(3) Polarization degree of the polarizer The polarization degree of the polarizer is measured using a spectrophotometer [product name “DOT-3” manufactured by Murakami Color Research Laboratory Co., Ltd.], and the parallel transmittance (H ₀ ) of the polarizer. Then, the orthogonal transmittance (H ₉₀ ) was measured and determined from the formula: degree of polarization (%) = {(H ₀ −H ₉₀ ) / (H ₀ + H ₉₀ )} ^1/2 × 100. The parallel transmittance (H ₀ ) is a transmittance value of a parallel laminated polarizer prepared by superposing two polarizers of the same type so that their absorption axes are parallel to each other. The orthogonal transmittance (H ₉₀ ) is a value of the transmittance of an orthogonal laminated polarizer produced by superposing two polarizers of the same type so that their absorption axes are orthogonal to each other. Note that these transmittances are Y values obtained by performing visibility correction with a two-degree field of view (C light source) defined in JlS Z 8701-1982.

(4) Phase difference value (Re [λ], Rth [λ]), Nz coefficient, T [590]
The phase difference values (Re [λ], Rth [λ]), Nz coefficient, and T [590] were measured at 23 ° C. using a trade name “KOBRA21-ADH” manufactured by Oji Scientific Instruments. In addition, the value measured using the Abbe refractometer [Atago Co., Ltd. product name "DR-M4"] was used for the average refractive index.

(5) Thickness When the thickness was less than 10 μm, measurement was performed using a spectrophotometer for thin film [manufactured by Otsuka Electronics Co., Ltd., “instant multi-photometry system MCPD-2000”]. When the thickness was 10 μm or more, measurement was performed using an Anritsu digital micrometer “KC-351C type”.

(6) Molecular weight The molecular weight was measured by a gel permeation chromatograph (GPC) method using polystyrene as a standard sample. Specifically, it measured with the following apparatuses, instruments, and measurement conditions.
Measurement sample: The sample was dissolved in tetrahydrane to give a 0.1 wt% solution, allowed to stand overnight, and then filtrated with a 0.45 μm membrane filter was used as the measurement sample.
Analyzer: Tosoh Corporation, trade name “SC-8020GPC”
Column: manufactured by Tosoh Corporation, trade name “TSKgel SuperHMH / H4000 / H3000 / H2000”
Column size: 6.0 mmI. D. × 150mm
Eluent: Tetrahydrofuran Flow rate: 0.6 ml / min.
Detector: RI
Column temperature: 40 ° C
Injection volume: 20 μl

(7) Glass transition temperature (Tg)
The glass transition temperature (Tg) is measured by a method according to JIS K 7121 (1987) (measurement method of plastic transition temperature) using a differential scanning calorimeter [product name “DSC-6200” manufactured by Seiko Co., Ltd.]. Asked. Specifically, a sample of 3 mg was heated twice (heating rate: 10 ° C./min) in a nitrogen atmosphere (gas flow rate: 80 ml / min), measured twice, and the second data was adopted. The calorimeter corrected the temperature using a standard material (indium).

(8) Contrast ratio After 30 minutes have passed since the backlight was turned on in a dark room at 23 ° C., an ELDIM product name “EZ Contrast 160D” was used to display an XYZ display system when displaying a white image and a black image. The Y value was measured. The contrast ratio “YW / YB” was calculated from the Y value (YW) in the white image and the Y value (YB) in the black image. The long side of the liquid crystal panel was set to an azimuth angle of 0 °, and the normal direction was set to a polar angle of 0 °.

[Liquid crystal cell]
[Reference Example 1]
A rectangular plate-like first substrate and second substrate were prepared. A rubbing process was performed on the surface of the first substrate in parallel with the long side. Further, rubbing treatment was performed on the surface of the second substrate in parallel with the short side direction. The two substrates were bonded together with a spacer in a state where the rubbing surfaces were opposed to each other. A liquid crystal material (manufactured by MERCK, trade name ZL1-4792) was injected into the gap between the substrates, and the edge between the substrates was sealed. In this manner, a TN mode liquid crystal cell having a rectangular surface shape, a cell gap of 4.5 μm, a cell interface pretilt angle of 3 °, a twist angle of 90 °, and Δnd: 440 nm was manufactured.

[Polarizer]
[Reference Example 2]
Commercially available polarizing plates (Nitto Denko Corporation, trade name “SIG1423DU”) were used as they were as the first polarizer and the second polarizer. This polarizing plate includes protective layers mainly composed of triacetyl cellulose on both sides of the polarizing film. The protective layer of the polarizing film is substantially isotropic, Re [590] is 0.5 nm, and Rth [590] is 5.0 nm. The polarizing plate had a single transmittance of 42.6% and a degree of polarization of 99.99%. In the following examples, the polarizing plate having the same characteristics was used as the first polarizer and the second polarizer.

[O-plate]
[Reference Example 3]
An alignment agent for photo-alignment film (trade name “ROF103” manufactured by Rolic Co., Ltd.) is formed on the surface of a hard film-treated polymer film substrate (thickness 80 μm, manufactured by Nitto Denko Corporation). Was applied with a spin coater (conditions: 3000 rpm for 1 minute) and dried in a 100 ° C. air circulation type thermostatic oven for 10 minutes to form a photo-alignment film having a thickness of 70 nm. Next, this photo-alignment film was irradiated with polarized ultraviolet light (irradiation amount: 50 mJ / cm ² ) from an oblique direction of 40 ° with respect to the substrate plane, and subjected to tilt alignment treatment. Next, a liquid crystal composition (a liquid crystal temperature range of 15 ° C. to 60 ° C.) containing a rod-like liquid crystal compound having two crosslinkable functional groups in the molecular structure and a polymerization initiator, and cyclobentanone (concentration: 20% by weight) And a coating solution (trade name “ROP5101” manufactured by Rolic). The coating liquid is applied to the surface of the photo-alignment film to form a coating film, and the interface of the coating film on the side opposite to the substrate side is in contact with air, and the temperature is set to 50 ° C. Heated and held at that temperature for 2 minutes to form a solidified layer in which the rod-like liquid crystal compound was aligned in a hybrid alignment. The solidified layer was irradiated with ultraviolet rays (irradiation amount: 500 mJ / cm ² : at 365 nm) in a nitrogen atmosphere to form a cured layer having a thickness of 1.1 μm on the polymer film (substrate). A plate was made. In the hardened layer (O plate), T [590] = 90%, Re [590] = 110 nm, the tilt angle (θ _air ) = 0 ° of the _air interface, and the tilt angle (θ _AL ) = 70 ° of the substrate interface. there were. In the following examples, the O plate having the same characteristics produced as described above was used as the first O plate and the second O plate. When using the O plate, the substrate was peeled off.

[Biaxial retardation layer]
[Reference Example 4]
A polymer film containing norbornene-based resin (thickness: 100 μm, trade name “Zeonor ZF14” (Tg = 136 ° C.) manufactured by Optes Co., Ltd.) is fixed at 150 ° C. by a fixed-end horizontal uniaxial stretching method using a tenter stretching machine. The film was stretched 2.56 times in the width direction of the film to prepare a biaxial retardation film (biaxial retardation layer). In the obtained retardation film, transmittance was 90%, Re [590] = 140 nm, Rth [590] = 217 nm, and Nz coefficient = 1.55. In the following examples and the like, the biaxial retardation film having the same characteristics was used as the first biaxial retardation layer and the second biaxial retardation layer.

[A plate]
[Reference Example 5]
By uniaxially stretching a long norbornene-based resin film (manufactured by Zeon Corporation: trade name Zeonor: thickness 60 μm: photoelastic coefficient 3.10 × 10 ⁻¹² m ² / N) at 145 ° C. by 2.7 times, A long A plate was prepared. This film had a thickness of 37 μm and an in-plane retardation Re of 140 nm. In the following examples and the like, the A plate having the same characteristics was used as the first A plate and the second A plate.

[Preparation of negative C plate]
[Reference Example 6]
90 parts by weight of a nematic liquid crystalline compound represented by the following formula (1), 10 parts by weight of a chiral agent represented by the following formula (2), a photopolymerization initiator (trade name Irgacure 907, manufactured by Ciba Specialty Chemicals) 5 Part by weight and 300 parts by weight of methyl ethyl ketone were uniformly mixed to prepare a liquid crystal coating liquid. This liquid crystal coating solution was coated on a substrate (biaxially stretched PET film), heat-treated at 80 ° C. for 3 minutes, and then polymerized by irradiation with ultraviolet rays to form a negative C plate. The negative C plate had a thickness of 1 μm, an in-plane retardation Re of 0.5 nm, and a thickness direction retardation Rth of 60 nm.

[Liquid crystal panel and liquid crystal display device]
(Example 1)
The angle formed between the slow axis of the first biaxial retardation layer of Reference Example 4 and the long side direction of the liquid crystal cell is 90 ° on the surface on the viewing side of the liquid crystal cell of Reference Example 1. In this way, lamination was performed via an acrylic pressure-sensitive adhesive (thickness: 20 μm). The first O-plate of Reference Example 3 is formed on the surface of the first biaxial retardation layer so that the angle formed by the alignment direction and the long side direction of the liquid crystal cell is 0 °. The material was transferred through an acrylic pressure-sensitive adhesive (thickness: 20 μm) while removing the material. An acrylic pressure-sensitive adhesive (on the surface of the first O plate) is formed so that the angle between the absorption axis of the first polarizer of Reference Example 2 and the long side direction of the liquid crystal cell is 0 °. (Thickness: 20 μm). At this time, in the rod-shaped liquid crystal compound of the first O plate, the tilt angle (θ _P ) on the polarizer side is 70 °, and the tilt angle (θ _B ) on the biaxial retardation layer side is 0. The alignment direction is substantially the same (parallel) to the alignment treatment (rubbing) direction of the liquid crystal cell. The slow axis of the first O plate is substantially parallel to the absorption axis of the first polarizer. The slow axis of the first biaxial retardation layer is substantially orthogonal to the absorption axis of the first polarizer.

Next, the second biaxial retardation layer of Reference Example 4 is formed on the backlight side surface of the liquid crystal cell, and the angle formed between the slow axis and the long side direction of the liquid crystal cell is 0 °. In this way, lamination was performed via an acrylic pressure-sensitive adhesive (thickness: 20 μm). Next, on the surface of the second biaxial retardation layer, the angle between the orientation direction of the second O plate of Reference Example 3 and the long side direction of the liquid crystal cell is 90 °. Then, the substrate was transferred through an acrylic pressure-sensitive adhesive (thickness: 20 μm) while removing the substrate. Next, on the surface of the second O-plate, the second polarizer of Reference Example 2 is acrylic so that the angle between the absorption axis and the long side direction of the liquid crystal cell is 90 °. It laminated | stacked through the adhesive (thickness: 20 micrometers). At this time, in the rod-like liquid crystal compound of the second O plate, the tilt angle (θ _P ) on the polarizer side is 70 °, and the tilt angle (θ _B ) on the biaxial retardation layer side is 0 °. The alignment direction is substantially the same (parallel) as the alignment treatment (rubbing) direction of the liquid crystal cell. The slow axis of the second O plate is substantially parallel to the absorption axis of the second polarizer. The slow axis of the second biaxial retardation layer is substantially orthogonal to the absorption axis of the second polarizer. The absorption axis of the first polarizer is substantially perpendicular to the absorption axis of the second polarizer. In addition, the sticking angle of each constituent member is a value obtained counterclockwise with the long side direction of the liquid crystal cell being 0 °. In this way, a liquid crystal panel 100 having a configuration as shown in FIGS. 1 and 2 was produced.

  The liquid crystal panel 100 was combined with a backlight unit taken out from a liquid crystal display device [BENQ Co., Ltd. 17-type liquid crystal monitor (model number: FP71 +)] including a TN mode liquid crystal cell to produce a liquid crystal display device. The light source of the backlight unit of the liquid crystal display device was turned on, and after 30 minutes, a driving voltage of 0 V was set for the liquid crystal cell for white display and 5 V for black display, and the contrast ratio was measured. FIG. 5 shows a contrast contour map of the liquid crystal display device. As shown in the figure, the liquid crystal display device of this example was excellent in the uniformity of the viewing angle in the vertical and horizontal directions.

(Example 2)
On the surface on the viewing side of the liquid crystal cell of Reference Example 1, the angle formed between the slow axis of the first A plate of Reference Example 5 and the long side direction of the liquid crystal cell is 90 °. It laminated | stacked through the acrylic adhesive (thickness: 20 micrometers). Next, the first O plate of Reference Example 3 is formed on the surface of the first A plate so that the angle between the alignment direction and the long side direction of the liquid crystal cell is 0 °. The material was transferred through an acrylic pressure-sensitive adhesive (thickness: 20 μm) while removing the material. Next, the negative C plate of Reference Example 6 was laminated on the surface of the first O plate with an acrylic pressure-sensitive adhesive (thickness: 20 μm). Next, on the surface of the negative C plate, an acrylic pressure-sensitive adhesive is used so that the angle between the absorption axis of the first polarizer of Reference Example 2 and the long side direction of the liquid crystal cell is 0 °. (Thickness: 20 μm). In the rod-shaped compound of the first O plate, the alignment direction is substantially the same (parallel) as the alignment treatment (rubbing) direction of the liquid crystal cell. The slow axis of the first O plate is substantially parallel to the absorption axis of the first polarizer. The slow axis of the first A plate is substantially orthogonal to the absorption axis of the first polarizer.

  Next, on the surface of the liquid crystal cell on the backlight side, the second A plate of Reference Example 5 is set so that the angle formed between the slow axis and the long side direction of the liquid crystal cell is 0 °. It laminated | stacked through the acrylic adhesive (thickness: 20 micrometers). Next, the second O plate of Reference Example 3 is formed on the surface of the second A plate so that the angle formed by the alignment direction and the long side direction of the liquid crystal cell is 90 °. Was transferred through an acrylic pressure-sensitive adhesive (thickness: 20 μm). Next, on the surface of the second O-plate, the second polarizer of Reference Example 2 is acrylic so that the angle between the absorption axis and the long side direction of the liquid crystal cell is 90 °. It laminated | stacked through the adhesive (thickness: 20 micrometers). In the rod-shaped compound of the second O plate, the alignment direction is substantially the same (parallel) as the alignment treatment (rubbing) direction of the liquid crystal cell. The slow axis of the second O plate is substantially parallel to the absorption axis of the second polarizer. The slow axis of the second A plate is substantially perpendicular to the absorption axis of the second polarizer. The absorption axis of the first polarizer is substantially perpendicular to the absorption axis of the second polarizer. In addition, the sticking angle of each constituent member is a value obtained counterclockwise with the long side direction of the liquid crystal cell being 0 °. Thus, the liquid crystal panel 101 having the configuration shown in FIG. 3 was produced.

  The liquid crystal panel 101 was combined with a backlight unit taken out from a liquid crystal display device [17 type liquid crystal monitor (model number: FP71 +) manufactured by BENQ Co., Ltd.] including a TN mode liquid crystal cell to produce a liquid crystal display device. The light source of the backlight unit of the liquid crystal display device was turned on, and after 30 minutes, a driving voltage of 0 V was set for the liquid crystal cell for white display and 5 V for black display, and the contrast ratio was measured. FIG. 6 shows a contrast contour map of the liquid crystal display device. As shown in the figure, the liquid crystal display device of this example was excellent in the uniformity of the viewing angle in the vertical and horizontal directions.

(Comparative Example 1)
9 except that the first biaxial retardation layer, the second biaxial retardation layer, the first O plate, and the second O plate were not used. A liquid crystal panel 102 having the structure shown in FIG. 6 was prepared, and a liquid crystal display device was manufactured by using the same method as in Example 1. In FIG. 9, the same parts as those in FIGS. 1 and 2 are denoted by the same reference numerals. FIG. 7 shows a contrast contour map of this liquid crystal display device. As shown in the figure, the liquid crystal display device of this comparative example was remarkably inferior in uniformity in the vertical and horizontal directions of the viewing angle.

(Comparative Example 2)
A liquid crystal panel 103 having the structure shown in FIG. 10 was produced in the same manner as in Example 2 except that the first A plate and the second A plate were not used. A liquid crystal display device was produced by the same method. In FIG. 10, the same parts as those in FIG. FIG. 8 shows a contrast contour map of this liquid crystal display device. As shown in the figure, the liquid crystal display device of this comparative example was remarkably inferior in the uniformity of the viewing angle in the vertical and horizontal directions.

  As described above, in the liquid crystal panel of the present invention, the first polarizer and the second polarizer have a relationship in which each absorption axis thereof is parallel or orthogonal to the rectangular side of the surface shape of the liquid crystal cell. Therefore, it is possible to use a polarizer with a good yield and low cost as the both polarizers, and excellent in the uniformity of the viewing angle in the vertical and horizontal directions. Therefore, the liquid crystal display device using the liquid crystal panel of the present invention is advantageous in terms of cost and excellent in display characteristics. Applications of the liquid crystal panel of the present invention and the liquid crystal display device using the same are, for example, OA devices such as desktop personal computers, notebook personal computers, and copy machines, mobile phones, watches, digital cameras, personal digital assistants (PDAs), and portable game machines. Mobile devices such as video cameras, televisions, microwave ovens and other household electrical equipment, back monitors, car navigation system monitors, car audio and other in-vehicle devices, commercial store information monitors and other display equipment, surveillance monitors Nursing care / medical equipment such as nursing equipment, nursing monitors, medical monitors, etc., among them, television is preferred, more preferably large screen television, but its use is not limited and applicable to a wide field Is possible.

FIG. 1 is a structural cross-sectional view showing the structure of an example of the liquid crystal panel of the present invention. FIG. 2 is an exploded perspective view of the above example. FIG. 3 is a structural sectional view showing the structure of another example of the liquid crystal panel of the present invention. FIG. 4 is a cross-sectional view showing the structure of an example of the liquid crystal display device of the present invention. FIG. 5 is a contrast contour map of one embodiment of the present invention. FIG. 6 is a contrast contour map of another embodiment of the present invention. FIG. 7 is a contrast contour map of Comparative Example 1. FIG. 8 is a contrast contour map of Comparative Example 2. FIG. 9 is a structural cross-sectional view showing the structure of the liquid crystal panel of Comparative Example 1. FIG. 10 is a structural cross-sectional view showing the structure of the liquid crystal panel of Comparative Example 2.

Explanation of symbols

1, 2 Orientation treatment (rubbing) direction 3, 4 Absorption axis 5, 6 Slow axis 7, 8 Director direction (orientation direction)
DESCRIPTION OF SYMBOLS 10 Liquid crystal cell 11 1st board | substrate 12 2nd board | substrate 13 Liquid crystal layer 21 1st polarizer 22 2nd polarizer 31 1st O plate 32 2nd O plate 33 Rod-shaped liquid crystal compound 41 1st biaxial Phase difference layer 42 second biaxial phase difference layer 43 first A plate 44 second A plate 51 negative C plate 80 backlight unit 81 light source 82 reflection film 83 diffuser plate 84 prism sheet 85 brightness enhancement film 100 , 101, 102, 103 Liquid crystal panel 200 Liquid crystal display device

Claims (12)

The liquid crystal cell has a first polarizer, a second polarizer, and a liquid crystal cell, and the liquid crystal cell is a liquid crystal cell in which liquid crystal molecules are twisted nematically aligned, and the first polarizer is a display of the liquid crystal cell. A liquid crystal panel disposed on a surface side, wherein the second polarizer is disposed on a back surface side of the liquid crystal cell, and further includes a first O plate, a second O plate, and a first optical compensation layer And the second optical compensation layer, the first optical compensation layer and the second optical compensation layer satisfy the relationship of the following formula (1), the surface shape of the liquid crystal cell is rectangular, 1. The liquid crystal panel according to claim 1, wherein the first polarizer and the second polarizer are arranged so that absorption axes thereof are parallel or orthogonal to a rectangular side of the surface shape of the liquid crystal cell.

nx> ny ≧ nz (1)

In the formula (1), nx is the maximum refractive index in the surface direction of the optical compensation layer, and ny is the refractive index in the direction orthogonal to the nx direction in the surface direction of the optical compensation layer. , Nz is the refractive index in the thickness direction of the optical compensation layer orthogonal to the nx and ny directions.
Between the first polarizer and the liquid crystal cell, the first optical compensation layer and the first O plate are arranged in this order from the liquid crystal cell side, and the second polarizer and The liquid crystal panel according to claim 1, wherein the second optical compensation layer and the second O plate are arranged in this order from the liquid crystal cell side to the liquid crystal cell. The liquid crystal panel according to claim 1, wherein the first optical compensation layer and the second optical compensation layer are biaxial retardation layers. The liquid crystal panel according to claim 1 or 2, wherein the first optical compensation layer and the second optical compensation layer are A plates. The liquid crystal cell further includes a negative C plate, and the first optical compensation layer and the second optical compensation layer are A plates, and the liquid crystal cell side is disposed between the first polarizer and the liquid crystal cell. From the liquid crystal cell side, the first optical compensation layer, the first O plate and the negative C plate are arranged in this order, and between the second polarizer and the liquid crystal cell, The liquid crystal panel according to claim 1, wherein the second optical compensation layer and the second O plate are arranged in this order. 6. The liquid crystal panel according to claim 1, wherein an absorption axis of the first polarizer and a slow axis of the first O plate are parallel to each other. The liquid crystal panel according to claim 1, wherein an absorption axis of the first polarizer and a slow axis of the first optical compensation layer are orthogonal to each other. The liquid crystal panel according to claim 1, wherein an absorption axis of the second polarizer and a slow axis of the second O plate are parallel to each other. 9. The liquid crystal panel according to claim 1, wherein an absorption axis of the second polarizer and a slow axis of the second optical compensation layer are orthogonal to each other. The liquid crystal panel according to any one of claims 1 to 9, wherein the first polarizer and the second polarizer are arranged so that absorption axes thereof are orthogonal to each other. The liquid crystal panel according to any one of claims 1 to 10, wherein the liquid crystal cell is a twisted nematic (TN) mode liquid crystal cell. A liquid crystal display device comprising a liquid crystal panel, wherein the liquid crystal panel is the liquid crystal panel according to claim 1.

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