JP2007279656A - Liquid crystal panel, liquid crystal display device using the same, and manufacturing method of liquid crystal panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal panel contributing to thinness and having excellent optical characteristics, to provide a liquid crystal display device and to provide a method with which the liquid crystal panel can be manufactured with high manufacturing efficiency. <P>SOLUTION: The liquid crystal panel has a first polarizer, a first optical compensation layer, a first negative C plate, a liquid crystal cell, a second negative C plate, a second optical compensation layer and a second polarizer in this order. The first optical compensation layer and the first negative C plate are disposed without using an adhesive, the second optical compensation layer and the second negative C plate are disposed without using an adhesive, the first and the second optical compensation layers are coating layers functioning as λ/4 plates and having 0.3 to 3 μm thicknesses and the first and the second negative C plates are coating layers having 0.5 to 10 μm thicknesses. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal panel and a liquid crystal display device using the same. More specifically, the present invention is a liquid crystal panel that contributes to thinning, has a wide band and a wide viewing angle, suppresses color shift, achieves good color reproducibility, and can satisfactorily prevent light leakage in black display, and The present invention relates to a liquid crystal display device and a method for manufacturing such a liquid crystal panel with very high manufacturing efficiency.

  As a VA mode liquid crystal display device, a transflective liquid crystal display device has been proposed in addition to a transmissive liquid crystal display device and a reflective liquid crystal display device (see, for example, Patent Documents 1 and 2). The transflective liquid crystal display device uses external light in a bright place in the same manner as the reflective liquid crystal display device, and allows display to be visually recognized by an internal light source such as a backlight in a dark place. In other words, the transflective liquid crystal display device employs a display method having both a reflective type and a transmissive type, and switches to either the reflective mode or the transmissive mode depending on the surrounding brightness. As a result, the transflective liquid crystal display device can be clearly displayed even when the surroundings are dark while reducing power consumption. Therefore, the transflective liquid crystal display device is suitably used for a display portion of a portable device. However, in these VA mode liquid crystal display devices, particularly transflective liquid crystal display devices, there is a problem that light leakage occurs in black display and the contrast is lowered, which has not been solved for a long time.

  In an attempt to solve such a problem, in order to obtain optimal optical compensation (for example, improved viewing angle characteristics, improved color shift, improved contrast), the optical characteristics of the retardation plate are optimized and / or Various attempts have been made for the arrangement in the liquid crystal display device. For example, liquid crystal display devices as shown in Patent Documents 3 and 4 have been proposed. Such a liquid crystal display device includes a first optical compensator disposed on both sides of the liquid crystal cell, a second optical compensator disposed outside the first optical compensator, and a second optical compensator. The polarizing plate is disposed on the outside. However, the first optical compensation plate and the second optical compensation plate used in such a liquid crystal display device each have a thickness of 50 μm or more, and it is very difficult to reduce the thickness of the liquid crystal display device.

  On the other hand, in order to obtain a thin liquid crystal display device and optimal optical compensation, a technology that uses a biaxial optical compensator to compensate for the effects of liquid crystal molecule birefringence and polarizing plate axial displacement on light leakage is proposed. Has been. However, although these techniques all contribute to the thinning of the liquid crystal display device, the improvement in viewing angle characteristics is insufficient.

As described above, there is a strong demand for a liquid crystal display device (liquid crystal panel) that can satisfy the demand for better display quality and thinner thickness.
Japanese Patent Laid-Open No. 11-242226 Japanese Patent Laid-Open No. 2001-209065 JP 2002-303869 A JP 2002-55342 A

  The present invention has been made in order to solve the above-described conventional problems. The object of the present invention is to contribute to a reduction in thickness, to have a wide bandwidth and a wide viewing angle, to suppress color shift, and to achieve good color reproducibility. It is desirable to provide a liquid crystal panel and a liquid crystal display device that can satisfactorily prevent light leakage during black display, and a method for manufacturing such a liquid crystal panel with very high manufacturing efficiency.

  The liquid crystal panel of the present invention includes a liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell, a second polarizer disposed on the other side of the liquid crystal cell, and the first A first optical compensation layer and a first negative C plate disposed between the polarizer and the liquid crystal cell, and a second negative disposed between the liquid crystal cell and the second polarizer. A C plate and a second optical compensation layer, wherein the first optical compensation layer is disposed on the first negative C plate without an adhesive, and the second optical compensation layer comprises a second optical compensation layer. A coating layer that is disposed on a negative C plate without an adhesive, and the first optical compensation layer and the second optical compensation layer function as a λ / 4 plate, each having a thickness of 0.3 to 3 μm. The first negative C plate and the second negative C plate Is a coating layer, and each thickness is 0.5-10 micrometers.

  In a preferred embodiment, the liquid crystal panel of the present invention includes a first polarizer, a first optical compensation layer, a first negative C plate, a liquid crystal cell, and a second negative electrode from the viewer side toward the backlight side. The C plate, the second optical compensation layer, and the second polarizer are arranged in this order.

  According to another aspect of the present invention, a liquid crystal display device is provided. The liquid crystal display device includes the liquid crystal panel.

  In yet another aspect of the present invention, a method for manufacturing a liquid crystal panel is provided. The manufacturing method includes a step of forming a first optical compensation layer on a surface of a first negative C plate; and a step of forming a first optical compensation layer on a surface opposite to the first negative C plate. Laminating one polarizer to obtain a first laminate; bonding the first negative C plate side of the first laminate to one surface of the liquid crystal cell; and second negative Forming a second optical compensation layer on the surface of the C plate; laminating a second polarizer on the surface of the second optical compensation layer opposite to the second negative C plate; A step of obtaining a second laminate; and a step of bonding the second negative C plate side of the second laminate to the other surface of the liquid crystal cell.

  In a preferred embodiment, the first negative C plate includes a step of applying a liquid crystal composition containing a liquid crystal material and a chiral agent to a substrate; and the liquid crystal material is a liquid crystal The substrate is peeled after the first laminated body is obtained.

  In another preferred embodiment, the first negative C plate has at least one non-liquid crystal polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide as a substrate. It is formed by a method including a step of applying a solution to be contained, and after the first laminated body is obtained, the substrate is peeled off.

  In a preferred embodiment, the method further includes a step of forming an alignment film on the surface of the first negative C plate opposite to the base material; and a step of performing an alignment treatment on the surface of the alignment film.

  In a preferred embodiment, the second negative C plate comprises a step of applying a liquid crystal composition containing a liquid crystal material and a chiral agent to a substrate; and the liquid crystal material is a liquid crystal The substrate is peeled after the second laminated body is obtained.

  In another preferred embodiment, the second negative C plate has at least one non-liquid crystal polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide as a base material. It is formed by a method including a step of applying a solution to be contained, and the substrate is peeled after the second laminate is obtained.

  In a preferred embodiment, the method further includes a step of forming an alignment film on a surface opposite to the base of the second negative C plate; and a step of performing an alignment treatment on the surface of the alignment film.

  As described above, according to the present invention, the specific optical compensation layer and the negative C plate arranged on both sides of the liquid crystal cell are all coating layers, and the optical compensation layer is not attached to the negative C plate via an adhesive. By disposing, the liquid crystal panel (liquid crystal display device) can contribute to thinning compared to the prior art. Furthermore, the liquid crystal panel of the present invention has a specific optical compensation layer and a negative C plate, so that a liquid crystal panel having a wide bandwidth and a wide viewing angle can be obtained particularly in a VA mode liquid crystal display device. It is possible to remarkably reduce the decrease in contrast due to leakage. In a preferred embodiment, the optical compensation layers disposed on both sides of the liquid crystal cell have the same characteristics (for example, constituent material, optical characteristics, thickness), and the negative C plate disposed on both sides of the liquid crystal cell is Have the same properties (eg, constituent materials, optical properties, thickness). By performing such a symmetrical arrangement, the color shift can be further reduced.

  In another embodiment of the present invention, a method for manufacturing the liquid crystal panel is provided. According to this manufacturing method, since the slow axis of the optical compensation layer can be set in any direction, a long polarizer (polarizing plate) stretched in the longitudinal direction (that is, having an absorption axis in the longitudinal direction) is used. can do. That is, a long polarizer, a long optical compensation layer that has been aligned to form a predetermined angle with respect to the longitudinal direction, and a negative C plate are aligned in the longitudinal direction (so-called roll to It can be continuously laminated (by roll), and a laminate can be obtained with very good production efficiency. In addition, since the optical compensation layer can be formed on the surface of the negative C plate without using an adhesive, it can contribute to thinning of the liquid crystal panel (liquid crystal display device) as compared with the prior art. As a result, there is no variation in the angle of the optical axis in each layer of the laminate, and as a result, a liquid crystal panel having no quality variation among products can be obtained. In addition, since no waste is generated by clipping, a low-cost liquid crystal panel can be obtained.

(Definition of terms and symbols)
Definitions of terms and symbols used herein are as follows:
(1) “nx” is the refractive index in the direction in which the in-plane refractive index is maximum (ie, the slow axis direction), and “ny” is the direction perpendicular to the slow axis in the plane (ie, fast phase) (Nz direction), and “nz” is the refractive index in the thickness direction. For example, “nx = ny” includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. In this specification, “substantially equal” is intended to include the case where nx and ny are different within a range that does not practically affect the overall polarization characteristics of the polarizing plate with an optical compensation layer.
(2) “In-plane retardation Re” refers to a retardation value in a film (layer) plane measured with light having a wavelength of 590 nm at 23 ° C. Re is the formula: Re = when the refractive index in the slow axis direction and the fast axis direction of the film (layer) at a wavelength of 590 nm is nx and ny, and d (nm) is the thickness of the film (layer). It is calculated by (nx−ny) × d.
(3) Thickness direction retardation Rth refers to a thickness direction retardation value measured at 23 ° C. with light having a wavelength of 590 nm. Rth is the formula: Rth = (nx) where the refractive index in the slow axis direction and the thickness direction of the film (layer) at a wavelength of 590 nm is nx and nz, and d (nm) is the thickness of the film (layer). -Nz) * d.
(4) The subscript “1” attached to the terms and symbols described in this specification represents the first optical compensation layer, and the subscript “2” represents the second optical compensation layer. “C” represents a negative C plate, “1C” represents a first negative C plate, and “2C” represents a second negative C plate.
(5) “λ / 4 plate” means a plate having a function of converting linearly polarized light having a specific wavelength into circularly polarized light (or circularly polarized light into linearly polarized light). The λ / 4 plate has an in-plane retardation value of about ¼ for a predetermined wavelength of light (usually in the visible light region).
(6) “Cholesteric alignment solidified layer” refers to a layer in which the constituent molecules of the layer have a helical structure, the helical axis is aligned substantially perpendicular to the plane direction, and the alignment state is fixed. Therefore, the “cholesteric alignment solidified layer” includes not only the case where the liquid crystal compound exhibits a cholesteric liquid crystal phase but also the case where the non-liquid crystal compound has a pseudo structure such as a cholesteric liquid crystal phase. For example, the “cholesteric alignment solidified layer” is obtained by applying a torsion with a chiral agent in a state where the liquid crystal material exhibits a liquid crystal phase and aligning it in a cholesteric structure (spiral structure), and performing a polymerization treatment or a crosslinking treatment in that state. It can be formed by fixing the alignment (cholesteric structure) of the liquid crystal material.
(7) “The wavelength range of selective reflection is 350 nm or less” means that the center wavelength λ of the wavelength range of selective reflection is 350 nm or less. For example, when the cholesteric alignment solidified layer is formed using a liquid crystal monomer, the center wavelength λ of the selective reflection wavelength region is represented by the following formula:
λ = n × P
Here, n represents the average refractive index of the liquid crystal monomer, and P represents the helical pitch (nm) of the cholesteric alignment fixed layer. The average refractive index n _is represented by _{(n o + n e) /} 2, it is usually in the range of 1.45 to 1.65. n _o denotes the ordinary refractive index of the liquid crystal monomer, n _e represents an extraordinary refractive index of the liquid crystal monomer.
(8) “Chiral agent” refers to a compound having a function of aligning a liquid crystal material (for example, nematic liquid crystal) so as to have a cholesteric structure.
(9) “Twisting force” means the ability of a chiral agent to twist a liquid crystal material and align it in a cholesteric structure (helical structure). In general, the torsional force is represented by the following formula:
Torsional force = 1 / (P × W)
As described above, P represents the helical pitch (nm) of the cholesteric alignment solidified layer. W represents a chiral agent weight ratio. The chiral agent weight ratio W is represented by W = [X / (X + Y)] × 100. Here, X is the weight of the chiral agent, and Y is the weight of the liquid crystal material.
(10) “Substantially orthogonal” means that the specified angle includes 90 ° ± 10 °, preferably 90 ° ± 5 °, and more preferably 90 ° ± 3 °.
(11) “Substantially parallel” means that the specified angle includes 0 ° ± 10 °, preferably 0 ° ± 5 °, and more preferably 0 ° ± 3 °.

A. Overall configuration of the LCD panel
FIG. 1 is a schematic cross-sectional view of a liquid crystal panel according to a preferred embodiment of the present invention. 2 and 3 are schematic exploded perspective views of a liquid crystal panel according to a preferred embodiment of the present invention. 2 and 3, A represents the absorption axis of the first polarizer, B represents the slow axis of the first optical compensation layer, and α represents the absorption axis A of the first polarizer and the first axis. Represents an angle defined by the slow axis B of the optical compensation layer. Similarly, in FIGS. 2 and 3, A ′ represents the absorption axis of the second polarizer, B ′ represents the slow axis of the second optical compensation layer, and α ′ represents the absorption axis of the second polarizer. It represents an angle defined by A ′ and the slow axis B ′ of the second optical compensation layer. In the example of FIG. 1, the liquid crystal panel 100 includes a first polarizer 11, a first optical compensation layer 21, a first negative C plate 31, and a liquid crystal in order from the viewing side to the backlight side. The cell 40, the second negative C plate 32, the second optical compensation layer 22, and the second polarizer 12 are included.

  The first polarizer 11 and the second polarizer 12 are typically arranged such that their absorption axes are substantially orthogonal to each other.

  The direction of the absorption axis of the first polarizer can be appropriately set according to the purpose. For example, the direction of the absorption axis of the first polarizer disposed on the viewing side of the liquid crystal cell may be substantially parallel to the longitudinal direction of the liquid crystal cell (in this case, the second polarizer The direction of the absorption axis is perpendicular to the longitudinal direction of the liquid crystal cell; see FIG. 2), and may be substantially perpendicular (in this case, the direction of the absorption axis of the second polarizer is It is parallel to the longitudinal direction of the liquid crystal cell; see FIG.

  Each of the first optical compensation layer 21 and the second optical compensation layer 22 is a coating layer that functions as a λ / 4 plate, and each has a thickness of 0.3 to 3 μm. Preferably, the slow axis of the first optical compensation layer 21 (B in FIGS. 2 and 3; the same applies hereinafter) is + 40 ° to + 50 ° or −40 ° with respect to the absorption axis A of the first polarizer 11. Define an angle of ~ -50 °. Preferably, the slow axis B ′ of the second optical compensation layer 22 defines an angle of + 40 ° to + 50 ° or −40 ° to −50 ° with respect to the absorption axis A ′ of the second polarizer 12. . The first optical compensation layer 21 and the second optical compensation layer 22 are typically arranged such that their slow axes are substantially perpendicular to each other. The first optical compensation layer 21 is disposed on the first negative C plate 31 without an adhesive, and the second optical compensation layer 22 is disposed on the second negative C plate 32 without an adhesive. . The first optical compensation layer and the second optical compensation layer may be the same coating layer or different coating layers. Preferably, the first optical compensation layer and the second optical compensation layer have the same characteristics (for example, constituent material, optical characteristics, thickness). By performing such a symmetrical arrangement, the color shift can be further reduced.

  Each of the first negative C plate 31 and the second negative C plate 32 is a coating layer and has a thickness of 0.5 to 10 μm. Preferably, the first negative C plate and / or the second negative C plate comprises a cholesteric alignment solidified layer. The first negative C plate and the second negative C plate may be the same coating layer or different coating layers. Preferably, the first negative C plate and the second negative C plate have the same characteristics (eg, constituent material, optical characteristics, thickness). By performing such a symmetrical arrangement, the color shift can be further reduced.

  Preferably, a first protective layer (not shown) is provided between the first polarizer 11 and the first optical compensation layer 21, and the second optical compensation layer 22, the second polarizer 12, A second protective layer (not shown) is provided between the two. Furthermore, practically, another protective layer (not shown) is provided on the opposite side of the first polarizer 11 from the first optical compensation layer 21 (outside of the first polarizer 11, on the viewing side in the illustrated example). And another protective layer (not shown) is provided on the opposite side of the second polarizer 12 from the second optical compensation layer 22 (outside of the second polarizer 12, the backlight side in the illustrated example). It is done.

  The liquid crystal cell 40 has a pair of glass substrates 41 and 42 and a liquid crystal layer 43 as a display medium disposed between the substrates. One substrate (active matrix substrate) 42 includes a switching element (typically a TFT) for controlling the electro-optical characteristics of the liquid crystal, a scanning line for supplying a gate signal to the switching element, and a signal line for supplying a source signal. Provided (none shown). The other glass substrate (color filter substrate) 41 is provided with a color filter (not shown). The color filter may be provided on the active matrix substrate 42. A distance (cell gap) between the substrates 41 and 42 is controlled by a spacer 44. An alignment film (not shown) made of polyimide, for example, is provided on the side of the substrates 41 and 42 in contact with the liquid crystal layer 43. Note that details of the liquid crystal cell are omitted in FIGS. 2 and 3 for simplicity.

As a driving mode of the liquid crystal cell 40, any appropriate driving mode can be adopted as long as the effect of the present invention can be obtained. Specific examples of the drive mode include STN (Super Twisted Nematic) mode, TN (Twisted Nematic) mode, IPS (In-Plane Switching) mode, VA (Vertical Aligned) mode, OCB (Optically Aligned Birefringence) mode, and HAN (Hybrid). Aligned Nematic) mode and ASM (Axially
Symmetric Aligned Microcell) mode. A VA mode is preferred, and a transmissive or transflective VA mode is more preferred.

  FIG. 4 is a schematic cross-sectional view illustrating the alignment state of liquid crystal molecules in the VA mode. As shown in FIG. 4A, the liquid crystal molecules are aligned perpendicular to the surfaces of the substrates 41 and 42 when no voltage is applied. Such vertical alignment can be realized by arranging a nematic liquid crystal having negative dielectric anisotropy between substrates on which a vertical alignment film (not shown) is formed. When light is incident from the surface of one substrate 41 in such a state, the linearly polarized light that has passed through the first polarizer 11 and entered the liquid crystal layer 43 is the major axis of the vertically aligned liquid crystal molecules. Proceed along the direction of Since no birefringence occurs in the major axis direction of the liquid crystal molecules, the incident light travels without changing the polarization direction and is absorbed by the second polarizer 12 having a polarization axis orthogonal to the first polarizer 11. This provides a dark display when no voltage is applied (normally black mode). As shown in FIG. 4B, when a voltage is applied between the electrodes, the long axes of the liquid crystal molecules are aligned parallel to the substrate surface. Liquid crystal molecules exhibit birefringence with respect to linearly polarized light incident on the liquid crystal layer 43 in this state, and the polarization state of incident light changes according to the inclination of the liquid crystal molecules. Light that passes through the liquid crystal layer when a predetermined maximum voltage is applied becomes, for example, linearly polarized light whose polarization direction is rotated by 90 °, and thus is transmitted through the second polarizer 12 to obtain a bright display. When the voltage is not applied again, the display can be returned to the dark state by the orientation regulating force. In addition, gradation display is possible by changing the applied voltage to control the tilt of the liquid crystal molecules to change the transmitted light intensity from the second polarizer 12. Hereinafter, details of each layer constituting the liquid crystal panel in the present invention will be described.

B. First and Second Optical Compensation Layers As described above, the first optical compensation layer and the second optical compensation layer (hereinafter sometimes collectively referred to as “optical compensation layer”) are each λ / It is the coating layer which functions as 4 plates, and each thickness is 0.3-3 micrometers. The thickness of the optical compensation layer is preferably 0.5 to 2.5 μm, more preferably 0.8 to 2 μm. Since the optical compensation layer (λ / 4 plate) is a coating layer, the thickness can be remarkably reduced as compared with the conventional one, which can greatly contribute to the thinning of the liquid crystal panel in the present invention. For example, the thickness of a λ / 4 plate by a conventional stretched film is about 60 μm, whereas the optical compensation layer in the present invention can realize a thickness of about 1/20 to 1/200.

  Preferably, the slow axis B of the first optical compensation layer may define an angle α of + 40 ° to + 50 ° or −40 ° to −50 ° with respect to the absorption axis A of the first polarizer. . The slow axis B of the first optical compensation layer is preferably + 42 ° to + 48 ° or −42 ° to −48 °, more preferably + 44 ° to + 46 ° with respect to the absorption axis of the first polarizer A. Alternatively, an angle α of −44 ° to −46 ° is defined. By disposing the polarizer and the optical compensation layer in such a specific positional relationship, a liquid crystal panel having an excellent balance between contrast and viewing angle characteristics can be obtained.

  Preferably, the slow axis B ′ of the second optical compensation layer has an angle α ′ of + 40 ° to + 50 ° or −40 ° to −50 ° with respect to the absorption axis A ′ of the second polarizer. Can be defined. The slow axis B ′ of the second optical compensation layer is preferably + 42 ° to + 48 ° or −42 ° to −48 °, more preferably + 44 ° to the absorption axis A ′ of the second polarizer. An angle α ′ of + 46 ° or −44 ° to −46 ° is defined. By disposing the polarizer and the optical compensation layer in such a specific positional relationship, a liquid crystal panel having an excellent balance between contrast and viewing angle characteristics can be obtained.

  The first optical compensation layer and the second optical compensation layer are preferably arranged so that their slow axes are substantially perpendicular to each other. By arranging the optical compensation layer in such a specific positional relationship, optimal optical compensation can be realized.

As described above, each of the first and second optical compensation layers can function as a so-called λ / 4 plate. The in-plane retardations Re ₁ and Re ₂ of the first and second optical compensation layers are each preferably 80 to 200 nm, more preferably 100 to 180 nm, and most preferably 120 to 160 nm at a wavelength of 590 nm. is there. Each of the first and second optical compensation layers preferably has a refractive index distribution of nx> ny = nz.

  As a material for forming the first and second optical compensation layers, any appropriate material can be adopted as long as the above characteristics are obtained. The optical compensation layer is preferably formed from a liquid crystal material. By using a liquid crystal material, the difference between nx and ny can be significantly increased compared to conventional polymer stretched films (for example, norbornene resins and polycarbonate resins). The thickness for obtaining can be significantly reduced. As such a liquid crystal material, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal material may exhibit a liquid crystallinity mechanism either lyotropic or thermotropic. The alignment state of the liquid crystal is preferably homogeneous alignment. A liquid crystal material may be used independently and may be used in combination of 2 or more type.

  When the liquid crystal material is a liquid crystal monomer, for example, a polymerizable monomer or a crosslinkable monomer is preferable. This is because the alignment state of the liquid crystal material can be fixed by polymerizing or crosslinking a polymerizable monomer or a crosslinkable monomer, as will be described later. After aligning the liquid crystal monomer, for example, if the liquid crystal monomers (polymerizable monomer or crosslinkable monomer) are polymerized or cross-linked, the alignment state can be fixed thereby. Here, a polymer is formed by polymerization and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystalline. Therefore, in the formed optical compensation layer, for example, transition to a liquid crystal phase, a glass phase, or a crystal phase due to a temperature change specific to the liquid crystal material does not occur. As a result, the optical compensation layer is not affected by temperature change and can be extremely excellent in stability.

  Any appropriate liquid crystal monomer can be adopted as the liquid crystal monomer. For example, polymerizable mesogenic compounds described in JP-T-2002-533742 (WO00 / 37585), EP358208 (US52111877), EP66137 (US4388453), WO93 / 22397, EP02661712, DE195504224, DE44081171, and GB2280445 can be used. Specific examples of such a polymerizable mesogenic compound include, for example, the trade name LC242 from BASF, the trade name E7 from Merck, and the trade name LC-Silicon-CC3767 from Wacker-Chem.

  As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable. Specific examples of the liquid crystal monomer include monomers described in paragraphs (0035) to (0046) of JP-A No. 2003-287623. These liquid crystal monomers can be used alone or in combination of two or more.

  The temperature range in which the liquid crystal monomer exhibits liquid crystal properties varies depending on the type. Specifically, the temperature range is preferably 40 to 120 ° C, more preferably 50 to 100 ° C, and most preferably 60 to 90 ° C.

  The liquid crystal material further includes at least one of a polymerization initiator and a crosslinking agent (curing agent) as necessary. These are particularly preferably used when a liquid crystal monomer is used as the liquid crystal material. As such a polymerization initiator or crosslinking agent, any appropriate substance can be adopted as long as the effects of the present invention can be obtained. Examples of the polymerization initiator include benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN). Examples of the crosslinking agent (curing agent) include an ultraviolet curing agent, a photocuring agent, and a thermosetting agent. More specifically, an isocyanate type crosslinking agent, an epoxy type crosslinking agent, a metal chelate crosslinking agent, etc. are mentioned. These may be used alone or in combination of two or more. The content of the polymerization initiator or crosslinking agent in the liquid crystal material is preferably 0.1 to 10% by weight, more preferably 0.5 to 8% by weight, and most preferably 1 to 5% by weight. .

  The liquid crystal material may further contain any appropriate additive as necessary. Examples of the additive include an anti-aging agent, a modifying agent, a surfactant, a dye, a pigment, a discoloration preventing agent, and an ultraviolet absorber. These additives may be used alone or in combination of two or more. More specifically, examples of the anti-aging agent include phenol compounds, amine compounds, organic sulfur compounds, and phosphine compounds. Examples of the modifier include glycols, silicones, and alcohols. The surfactant is added, for example, to smooth the surface of the optical compensation layer, and examples thereof include silicone-based, acrylic-based, and fluorine-based surfactants.

C. First and second negative C plates The first and second negative C plates (hereinafter sometimes collectively referred to as “negative C plates”) are coating layers, each having a thickness of 0.5. 10 μm. The thickness of the negative C plate is preferably 1.0 to 8 μm, more preferably 1.5 to 5 μm. Thus, the thickness of the negative C plate in the present invention is thin and can greatly contribute to the thinning of the liquid crystal panel. By forming the negative C plate thin, heat unevenness can be prevented. Further, such a thin negative C plate is preferable from the viewpoints of prevention of disorder of liquid crystal alignment and transmittance reduction, selective reflectivity, prevention of coloring, productivity, and the like.

  The negative C plate has a relationship of nx = ny> nz. Since the negative C plate has such a refractive index distribution, the birefringence of the liquid crystal layer of the VA mode liquid crystal cell can be compensated particularly well. More specifically, the negative C plate in a VA mode (vertical alignment mode) liquid crystal display device is deteriorated in viewing angle characteristics due to an isotropic collapse due to the influence of liquid crystal molecules when viewed from an oblique direction. Used to prevent this. As a result, a liquid crystal display device with significantly improved viewing angle characteristics can be obtained.

In the present specification, “nx = ny” includes not only the case where nx and ny are exactly equal, but also the case where nx and ny are substantially equal. Therefore, the first and second negative C plates are in-plane positions. It may have phase differences Re _1C and Re _2C and may have a slow axis. The in-plane retardation Re _1C and Re _2C practically acceptable for the negative C plate is preferably 0 to 20 nm, more preferably 0 to 10 nm, and most preferably 0 to 5 nm. The thickness direction retardations Rth _1C and Rth _2C of the first and second negative C plates are preferably 30 to 300 nm, more preferably 60 to 180 nm, particularly preferably 80 to 150 nm, and most preferably 100 to 140 nm. is there.

  The negative C plate in the present invention is formed from any appropriate coating layer as long as the above thickness and optical properties can be obtained. Preferably, a cholesteric alignment fixed layer is mentioned.

  The cholesteric alignment solidified layer is preferably a cholesteric alignment solidified layer having a selective reflection wavelength region of 350 nm or less. The upper limit of the wavelength range of selective reflection is more preferably 320 nm or less, and most preferably 300 nm or less. On the other hand, the lower limit of the wavelength range of selective reflection is preferably 100 nm or more, and more preferably 150 nm or more. When the wavelength range of selective reflection exceeds 350 nm, the wavelength range of selective reflection enters the visible light region, and thus, for example, a problem of coloring or color loss may occur. If the selective reflection wavelength region is smaller than 100 nm, the amount of chiral agent (to be described later) to be used becomes too large. Therefore, it is necessary to control the temperature at the time of forming the negative C plate very precisely. As a result, it may be difficult to manufacture the liquid crystal panel.

  The helical pitch in the cholesteric alignment solidified layer is preferably 0.01 to 0.25 μm, more preferably 0.03 to 0.20 μm, and most preferably 0.05 to 0.15 μm. If the helical pitch is 0.01 μm or more, for example, sufficient orientation can be obtained. If the helical pitch is 0.25 μm or less, for example, the optical rotation on the short wavelength side of visible light can be sufficiently suppressed, so that light leakage or the like can be sufficiently avoided. The helical pitch can be controlled by adjusting the type (twisting force) and amount of the chiral agent described below. By adjusting the helical pitch, the wavelength range of selective reflection can be controlled within a desired range.

  When the negative C plate is a cholesteric alignment solidified layer, the negative C plate in the present invention is formed from any appropriate material as long as the above thickness and optical characteristics can be obtained. Preferably, it can be formed from a liquid crystal material, and more preferably from a liquid crystal composition containing a liquid crystal material and a chiral agent. Any appropriate liquid crystal material can be adopted as the liquid crystal material. A liquid crystal material (nematic liquid crystal) in which the liquid crystal phase is a nematic phase is preferable. As such a liquid crystal material, for example, a liquid crystal polymer or a liquid crystal monomer can be used. The liquid crystal material may exhibit a liquid crystallinity mechanism either lyotropic or thermotropic. The alignment state of the liquid crystal is preferably homogeneous alignment.

  The content of the liquid crystal material in the liquid crystal composition is preferably 75 to 95% by weight, and more preferably 80 to 90% by weight. When the content of the liquid crystal material is less than 75% by weight, the composition does not sufficiently exhibit a liquid crystal state, and as a result, cholesteric alignment may not be sufficiently formed. When the content of the liquid crystal material exceeds 95% by weight, the content of the chiral agent is reduced and the twist is not sufficiently imparted, so that the cholesteric alignment may not be sufficiently formed.

  The liquid crystal material is preferably a liquid crystal monomer (for example, a polymerizable monomer and a crosslinkable monomer). Any appropriate liquid crystal monomer can be adopted as the liquid crystal monomer. Specific examples of the liquid crystal monomer include the monomers described in paragraphs (0035) to (0046) of JP-A No. 2003-287623 as in the above-mentioned item B. These liquid crystal monomers can be used alone or in combination of two or more.

  Preferably, the liquid crystal composition capable of forming a negative C plate contains a chiral agent. By forming the negative C plate from a liquid crystal composition containing a liquid crystal monomer and a chiral agent, the difference between nx and nz can be made very large (nx >> nz). As a result, the negative C plate can be thinned. For example, while the conventional negative C plate by biaxial stretching has a thickness of 60 μm or more, the negative C plate in the present invention can achieve a thickness of about 1/6 to 1/120. As a result, the liquid crystal panel can be greatly reduced in thickness.

  The content of the chiral agent in the liquid crystal composition is preferably 5 to 23% by weight, more preferably 10 to 20% by weight. When the content is less than 5% by weight, the twist is not sufficiently imparted, so that the cholesteric orientation may not be sufficiently formed. When the content exceeds 23% by weight, the temperature range in which the liquid crystal material exhibits a liquid crystal state becomes very narrow. Therefore, it is necessary to perform temperature control at the time of forming the negative C plate very precisely. As a result, it may be difficult to manufacture the negative C plate. In addition, a chiral agent can be used individually or in combination of 2 or more types.

As the chiral agent, any appropriate material that can align the liquid crystal material into a desired cholesteric structure can be adopted. For example, the twisting force of such a chiral agent is preferably 1 × 10 ⁻⁶ nm ⁻¹ · (wt%) ⁻¹ or more, and more preferably 1 × 10 ⁻⁵ nm ⁻¹ · (wt%) ^{−. 1} to 1 × 10 ⁻² nm ⁻¹ · (wt%) ⁻¹ , most preferably 1 × 10 ⁻⁴ nm ⁻¹ · (wt%) ⁻¹ to 1 × 10 ⁻³ nm ⁻¹ · (wt %) ^-1 . By using a chiral agent having such a twisting force, the helical pitch of the cholesteric alignment solidified layer can be controlled to a desired range, and as a result, the wavelength range of selective reflection can be controlled to a desired range. . For example, when a chiral agent having the same torsional force is used, the wavelength range of selective reflection of the formed negative C plate becomes lower as the content of the chiral agent in the liquid crystal composition is larger. For example, if the content of the chiral agent in the liquid crystal composition is the same, the greater the torsional force of the chiral agent, the lower the wavelength range of selective reflection of the formed negative C plate. A more specific example is as follows: When the wavelength range of selective reflection of the formed negative C plate is set in the range of 200 to 220 nm, for example, the twisting force is 5 × 10 ⁻⁴ nm ^−1. -(Wt%) ^-1 chiral agent may be contained in the liquid crystal composition at a ratio of 11 to 13 wt%. When the wavelength range of selective reflection of the formed negative C plate is set to a range of 290 to 310 nm, for example, a chiral agent having a twisting force of 5 × 10 ⁻⁴ nm ⁻¹ · (wt%) ⁻¹ is used. What is necessary is just to make it contain in the ratio of 7-9 weight% in a liquid-crystal composition.

  The chiral agent is preferably a polymerizable chiral agent. Specific examples of the polymerizable chiral agent include the chiral agents described in paragraphs (0048) to (0055) of JP-A No. 2003-287623.

  In addition to the above-mentioned chiral compounds, for example, chiral compounds described in RE-A 4342280 and German Patent Applications 19520660.6 and 195207041 can be preferably used.

  As the combination of the liquid crystal material and the chiral agent, any appropriate combination can be adopted depending on the purpose. Particularly preferable combinations include a combination of a liquid crystal monomer of the following formula (1) / a chiral agent of the following formula (3), a combination of a liquid crystal monomer of the following formula (1) / a chiral agent of the following formula (4), and the following formula (2 ) Liquid crystal monomer / chiral agent of the following formula (5), and the like.

  Preferably, the liquid crystal composition capable of forming the negative C plate further includes at least one of a polymerization initiator and a crosslinking agent (curing agent). By using a polymerization initiator and / or a crosslinking agent (curing agent), the cholesteric structure (cholesteric alignment) formed in the liquid crystal state by the liquid crystal material can be fixed. As such a polymerization initiator or crosslinking agent, any appropriate substance can be adopted as long as the effects of the present invention can be obtained. The polymerization initiator and the crosslinking agent (curing agent) are as described in the above section B. These may be used alone or in combination of two or more. The content of the polymerization initiator or crosslinking agent in the liquid crystal composition is preferably 0.1 to 10% by weight, more preferably 0.5 to 8% by weight, and most preferably 1 to 5% by weight. is there. When the content is less than 0.1% by weight, the fixation of the cholesteric structure may be insufficient. If the content exceeds 10% by weight, the temperature range in which the liquid crystal material exhibits a liquid crystal state is narrowed, so that temperature control in forming a cholesteric structure may be difficult.

  The liquid crystal composition may further contain any appropriate additive as required. Specific examples of the additive are as described in the above section B. These additives may be used alone or in combination of two or more.

  In the present invention, polyamides, polyimides, polyesters, polyether ketones, polyamideimides, and polyesterimides described in (0018) to (0072) of JP-A No. 2004-46065 are also preferably used as a material for forming the negative C plate. be able to.

D. Polarizer The first polarizer and the second polarizer are typically arranged such that their absorption axes are orthogonal to each other. The direction of the absorption axis of the first polarizer can be appropriately set according to the purpose. For example, the direction of the absorption axis of the first polarizer disposed on the viewing side of the liquid crystal cell may be substantially parallel to the longitudinal direction of the liquid crystal cell (in this case, the second polarizer The direction of the absorption axis is perpendicular to the longitudinal direction of the liquid crystal cell; see FIG. 2), and may be substantially perpendicular (in this case, the direction of the absorption axis of the second polarizer is It is parallel to the longitudinal direction of the liquid crystal cell; see FIG.

  Any appropriate polarizer may be adopted as the polarizer depending on the purpose. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And polyene-based oriented films such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product and a polyvinyl chloride dehydrochlorinated product. Among these, a polarizer obtained by adsorbing a dichroic substance such as iodine on a polyvinyl alcohol film and uniaxially stretching is particularly preferable because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about 1 to 80 μm.

  A polarizer uniaxially stretched by adsorbing iodine to a polyvinyl alcohol film can be produced by, for example, dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. . If necessary, it may contain boric acid, zinc sulfate, zinc chloride, or the like, or may be immersed in an aqueous solution such as potassium iodide. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing.

  By washing the polyvinyl alcohol film with water, not only can the surface of the polyvinyl alcohol film be cleaned and the anti-blocking agent can be washed, but also the effect of preventing unevenness such as uneven dyeing can be obtained by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

E. Protective layer Arbitrary suitable films may be employ | adopted as said protective layer (a 1st protective layer, a 2nd protective layer, and another protective layer). A transparent protective film is preferred. Specific examples of the material that is the main component of such a film include cellulose resins such as triacetylcellulose (TAC), polyester-based, polyvinyl alcohol-based, polycarbonate-based, polyamide-based, polyimide-based, polyethersulfone-based, Examples thereof include transparent resins such as polysulfone, polystyrene, polynorbornene, polyolefin, acrylic, and acetate. In addition, thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone, or ultraviolet curable resins are also included. In addition to this, for example, a glassy polymer such as a siloxane polymer is also included. Moreover, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) can also be used. As a material for this film, for example, a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and nitrile group in the side chain For example, a resin composition having an alternating copolymer composed of isobutene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned. The polymer film may be an extruded product of the resin composition, for example. TAC, polyimide resin, polyvinyl alcohol resin, and glassy polymer are preferable, and TAC is more preferable. Each protective layer may be the same or different. These protective layers may be subjected to an appropriate orientation treatment on the surface as necessary.

  The protective layer is preferably transparent and has no color. Specifically, the thickness direction retardation value is preferably −90 nm to +90 nm, more preferably −80 nm to +80 nm, and most preferably −70 nm to +70 nm.

  As the thickness of the protective layer, any appropriate thickness can be adopted as long as the preferable thickness direction retardation is obtained. Specifically, the thickness of the protective layer is preferably 5 mm or less, more preferably 1 mm or less, particularly preferably 1 to 500 μm, and most preferably 5 to 150 μm.

  The protective layer provided on the outer side of the polarizer (on the side opposite to the optical compensation layer) can be subjected to a hard coat treatment, an antireflection treatment, an antisticking treatment, an antiglare treatment, or the like as necessary.

F. Adhesive Layer For example, the first optical compensation layer is bonded to the first polarizer (or the first protective layer) via any appropriate adhesive layer. The second optical compensation layer is bonded to the second polarizer (or the second protective layer) via any appropriate adhesive layer. By using the adhesive layer, for example, when the liquid crystal panel according to the present invention is incorporated, it is possible to prevent the relationship between the optical axes of the layers from being shifted, and to prevent the layers from being rubbed and damaged. Further, the interface reflection between layers can be reduced, and the contrast can be increased when used in an image display apparatus. Any appropriate adhesive layer is selected as the adhesive layer depending on the purpose. Any suitable adhesive or pressure-sensitive adhesive is preferably used.

  A typical example of the adhesive forming the adhesive layer is a curable adhesive. Typical examples of the curable adhesive include a photocurable adhesive such as an ultraviolet curable adhesive, a moisture curable adhesive, and a thermosetting adhesive. Specific examples of the thermosetting adhesive include thermosetting resin adhesives such as epoxy resins, isocyanate resins, and polyimide resins. Specific examples of the moisture curable adhesive include isocyanate resin-based moisture curable adhesive. A moisture curable adhesive (especially an isocyanate resin-based moisture curable adhesive) is preferred. Moisture curable adhesives cure by reacting with moisture in the air, adsorbed water on the surface of the adherend, active hydrogen groups such as hydroxyl groups and carboxyl groups, and so on. It can be cured and has excellent operability. Furthermore, since it is not necessary to heat at high temperature for curing, the optical compensation layer and the like are not heated at high temperature. As a result, since there is no fear of heat shrinkage, cracks and the like during lamination can be prevented even when the optical compensation layer and the negative C plate are very thin as in the present invention. In addition, the curable adhesive hardly stretches even when heated after curing. Therefore, even when the optical compensation layer and the negative C plate are extremely thin, and the obtained liquid crystal panel is used under high temperature conditions, cracking of the optical compensation layer and the negative C plate can be prevented. . The isocyanate resin adhesive is a general term for polyisocyanate resin adhesives and polyurethane resin adhesives.

  As the curable adhesive, for example, a commercially available adhesive may be used, or the above various curable resins may be dissolved or dispersed in a solvent to prepare a curable resin adhesive solution (or dispersion). Good. When preparing a solution (or dispersion liquid), the content of the curable resin in the solution is preferably 10 to 80% by weight, more preferably 20 to 65% by weight, and particularly preferably the solid content weight. It is 25 to 65% by weight, and most preferably 30 to 50% by weight. As a solvent to be used, any appropriate solvent can be adopted depending on the type of curable resin. Specific examples include ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene and the like. These may be used alone or in combination of two or more.

The coating amount of the adhesive can be appropriately set according to the purpose. For example, the coating amount is preferably 0.3 to 3 ml, more preferably 0.5 to ² ml, most preferably 1 to ² ml per area (cm ² ) of the optical compensation layer.

  After coating, if necessary, the solvent contained in the adhesive is volatilized by natural drying or heat drying. The thickness of the adhesive layer thus obtained is preferably 0.1 μm to 20 μm, more preferably 0.5 μm to 15 μm, and most preferably 1 μm to 10 μm.

  The indentation hardness (microhardness) of the adhesive layer is preferably 0.1 to 0.5 GPa, more preferably 0.2 to 0.5 GPa, and most preferably 0.3 to 0.4 GPa. In addition, since the indentation hardness has a known correlation with Vickers hardness, it can also be converted into Vickers hardness. The indentation hardness can be calculated from the indentation depth and the indentation load using, for example, a thin film hardness meter (for example, trade name MH4000, trade name MHA-400) manufactured by NEC Corporation.

  As the above-mentioned pressure-sensitive adhesive, an acrylic polymer is used as a base polymer because it is particularly excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and is excellent in weather resistance and heat resistance. An acrylic adhesive is preferably used. A suitable thickness of the pressure-sensitive adhesive is generally 1 to 100 μm, preferably 5 to 80 μm, and particularly preferably 10 to 50 μm.

G. Manufacturing method of liquid crystal panel G-1. Method for Manufacturing Liquid Crystal Panel In another aspect of the present invention, a method for manufacturing a liquid crystal panel is provided. In a preferred embodiment, a method for manufacturing a liquid crystal panel includes: forming a first optical compensation layer on a surface of a first negative C plate; and what is the first negative C plate of the first optical compensation layer? A step of laminating a first polarizer on the opposite surface to obtain a first laminate; and bonding the first negative C plate side of the first laminate to one surface of the liquid crystal cell Forming a second optical compensation layer on the surface of the second negative C plate; and forming a second optical compensation layer on the surface of the second optical compensation layer opposite to the second negative C plate, A step of laminating a polarizer to obtain a second laminate; and a step of bonding the second negative C plate side of the second laminate to the other surface of the liquid crystal cell.

  In another embodiment, a method for producing a liquid crystal panel includes a step of performing an alignment treatment on the surface of the first protective layer; and a first optical compensation layer on the surface of the first protective layer subjected to the alignment treatment. Forming a first polarizer on the surface of the first protective layer; and forming a first negative C plate on the opposite side of the first optical compensation layer from the first protective layer. Forming a first laminated body on the surface; bonding the first negative C plate side of the first laminated body to one surface of the liquid crystal cell; and on the surface of the second protective layer A step of performing an alignment treatment; a step of forming a second optical compensation layer on the surface of the second protective layer that has been subjected to the alignment treatment; and a second polarizer laminated on the surface of the second protective layer Forming a second negative C plate on the surface of the second optical compensation layer opposite to the second protective layer; And obtaining a second laminate; a second negative C plate side of the second laminate and a step of bonding the other surface of the liquid crystal cell.

  According to such a manufacturing method, for example, a liquid crystal panel as shown in FIG. 1 is obtained. The order of each of the above steps can be appropriately changed according to the purpose. For example, when a protective layer is provided between the polarizer and the optical compensation layer, the polarizer may be previously laminated on the protective layer, and the protective layer is bonded to the laminate of the negative C plate and the optical compensation layer. After that, a polarizer may be laminated, or after forming an optical compensation layer on the protective layer, a polarizer may be laminated. Details of each step will be described below. In addition, the manufacturing method of a polarizer is as the above-mentioned D term.

G-2. Method for Forming Negative C Plate A typical example of a method for forming a negative C plate is shown below. These methods are not limited to the first negative C plate, and the second negative C plate can be formed in the same manner. The procedure in a typical method for forming a negative C plate is as follows.

G-2-1. First, a method for forming a cholesteric alignment solidified layer will be described as an example. As this formation method, any appropriate method can be adopted as long as a desired cholesteric alignment solidified layer is obtained. A typical method for forming a cholesteric alignment fixed layer is to apply a liquid crystal composition (for example, including a liquid crystal material and a chiral agent) to a base material, and align the liquid crystal material contained in the liquid crystal composition on the base material. Specifically, a coating liquid in which the liquid crystal composition is dissolved or dispersed in an appropriate solvent is prepared, and this coating liquid is applied to the substrate surface that has been subjected to appropriate alignment treatment (described later) as necessary. do it. The alignment of the liquid crystal material includes a step of performing a heat treatment so that the liquid crystal material used has a cholesteric alignment; and a step of fixing at least one of a polymerization treatment and a crosslinking treatment to fix the alignment of the liquid crystal material. Including.

  In another embodiment, the method for forming a cholesteric alignment solidified layer includes applying a liquid crystal composition (for example, a liquid crystal material and a chiral agent) to an optical compensation layer, and optically compensating the liquid crystal material contained in the liquid crystal composition. Orient on the layer. Specifically, a coating solution in which the liquid crystal composition is dissolved or dispersed in an appropriate solvent is prepared, and this coating solution may be applied to the surface of the optical compensation layer formed in advance. The alignment of the liquid crystal material includes a step of performing a heat treatment so that the liquid crystal material used has a cholesteric alignment; and a step of fixing at least one of a polymerization treatment and a crosslinking treatment to fix the alignment of the liquid crystal material. Including.

  Hereinafter, an example of a procedure of a more specific method for forming the cholesteric alignment solidified layer in the case of using the liquid crystal composition will be described. Here, for the sake of simplicity, only a method for forming a cholesteric alignment solidified layer on a substrate will be described.

  As the solvent, any suitable solvent that can dissolve or disperse the liquid crystal composition can be adopted. The type of the solvent used can be appropriately selected according to the type of the liquid crystal composition. Specific examples of the solvent include halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, methylene chloride, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene, phenol, p-chlorophenol, and o-chlorophenol. , M-cresol, o-cresol, p-cresol and other phenols, benzene, toluene, xylene, mesitylene, methoxybenzene, 1,2-dimethoxybenzene and other aromatic hydrocarbons, acetone, methyl ethyl ketone (MEK), methyl Ketone solvents such as isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone and N-methyl-2-pyrrolidone, ester solvents such as ethyl acetate, butyl acetate and propyl acetate Alcohol solvents such as t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, 2-methyl-2,4-pentanediol, dimethylformamide, dimethyl Amide solvents such as acetamide, nitrile solvents such as acetonitrile and butyronitrile, ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran and dioxane, or carbon disulfide, ethyl cellosolve, butyl cellosolve, ethyl cellosolve, etc. It is done. Preferred are toluene, xylene, mesitylene, MEK, methyl isobutyl ketone, cyclohexanone, ethyl cellosolve, butyl cellosolve, ethyl acetate, butyl acetate, propyl acetate, and ethyl cellosolve. These solvents may be used alone or in combination of two or more.

  The viscosity of the coating liquid containing the liquid crystal composition can vary depending on the content and temperature of the liquid crystal material. For example, when the concentration of the liquid crystal material is 5 to 70% by weight at about room temperature (20 to 30 ° C.), the viscosity of the coating liquid is preferably 0.2 to 20 mPa · s, more preferably 0.8. 5 to 15 mPa · s, most preferably 1 to 10 mPa · s. More specifically, when the concentration of the liquid crystal material is 30% by weight, the viscosity of the coating liquid is preferably 2 to 5 mPa · s, and more preferably 3 to 4 mPa · s. If the viscosity of the coating liquid is 0.2 mPa · s or more, generation of liquid flow due to running of the coating liquid can be prevented very well. Moreover, if the viscosity of a coating liquid is 20 mPa * s or less, the negative C plate which does not have thickness nonuniformity and has the very outstanding surface smoothness will be obtained. Furthermore, it is excellent in coatability.

  Next, a coating liquid containing the liquid crystal composition is applied onto the substrate to form a spread layer. Any appropriate method (typically, a method in which a liquid crystal composition-containing coating solution is fluidly developed) may be employed as a method for forming the spreading layer. Specific examples include a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, an extrusion method, a curtain coating method, and a spray coating method. Of these, spin coating and extrusion coating are preferred from the viewpoint of coating efficiency.

The coating amount of the coating liquid containing the liquid crystal composition can be appropriately set according to the concentration of the coating liquid, the target layer thickness, and the like. For example, when the liquid crystal material concentration of the coating liquid is 20% by weight, the coating amount is preferably 0.03 to 0.17 ml, more preferably 0.05 to 0.17 per area (100 cm ² ) of the base material. 0.15 ml, most preferably 0.08 to 0.12 ml.

As the base material, any appropriate base material capable of aligning the liquid crystal material can be adopted. Typically, various plastic films are mentioned. Although it does not restrict | limit especially as a plastic, For example, polyolefin, such as a triacetyl cellulose (TAC), polyethylene, a polypropylene, poly (4-methyl pentene-1) norbornene-type polyolefin, a polyimide, a polyimide amide, polyether imide, polyamide, poly Ether ether ketone, polyether ketone, polyketone sulfide, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulose Plastics, epoxy resin, phenol resin . Moreover, what arrange | positioned the above plastic films and sheet | seats on surfaces, such as metal base materials, such as aluminum, copper, and iron, a ceramic base material, and a glass base material, can also be used. Can also be used that form a SiO ₂ oblique deposition film on the substrate or the plastic film or the surface of the sheet. The thickness of the substrate is preferably 5 to 500 μm, more preferably 10 to 200 μm, and most preferably 15 to 150 μm. If it is such thickness, since it has sufficient intensity | strength as a base material, generation | occurrence | production of problems, such as fracture at the time of manufacture, can be prevented, for example. These substrates may be subjected to an appropriate orientation treatment on the surface as necessary.

  Next, the liquid crystal composition is subjected to a heat treatment so that the liquid crystal material is aligned in a state showing a liquid crystal phase. Since the liquid crystal composition contains a chiral agent together with the liquid crystal material, the liquid crystal material is twisted and aligned while exhibiting a liquid crystal phase. As a result, the liquid crystal material exhibits a cholesteric structure (helical structure).

  The temperature condition of the heat treatment can be appropriately set according to the type of the liquid crystal material (specifically, the temperature at which the liquid crystal material exhibits liquid crystallinity). Specifically, processing temperature becomes like this. Preferably it is 40-120 degreeC, More preferably, it is 50-100 degreeC, Most preferably, it is 60-90 degreeC. The treatment time is preferably 30 seconds or longer, more preferably 1 minute or longer, particularly preferably 2 minutes or longer, and most preferably 4 minutes or longer. When the treatment time is less than 30 seconds, the liquid crystal material may not take a sufficient liquid crystal state. On the other hand, the treatment time is preferably 10 minutes or less, more preferably 8 minutes or less, and most preferably 7 minutes or less. When processing time exceeds 10 minutes, there exists a possibility that an additive may sublime.

  Next, in a state where the liquid crystal composition exhibits a cholesteric structure, the alignment (cholesteric structure) of the liquid crystal material is fixed by performing a polymerization treatment or a crosslinking treatment. More specifically, by performing a polymerization treatment, the liquid crystal material (polymerizable monomer) and / or chiral agent (polymerizable chiral agent) is polymerized, and the polymerizable monomer and / or polymerizable chiral agent is a polymer molecule. Fixed as a repeating unit. Further, by performing the crosslinking treatment, the liquid crystal material (crosslinkable monomer) and / or the chiral agent forms a three-dimensional network structure, and the crosslinking monomer and / or the chiral agent is fixed as a part of the crosslinked structure. The As a result, the alignment state of the liquid crystal material is fixed. The polymer or three-dimensional network structure formed by polymerizing or crosslinking the liquid crystal material is “non-liquid crystalline”. Therefore, in the formed negative C plate (cholesteric alignment solidified layer), for example, liquid crystal molecules There is no transition to the liquid crystal phase, glass phase, or crystal phase due to a specific temperature change. Therefore, no change in orientation due to temperature occurs. As a result, the formed negative C plate can be used as a high performance negative C plate that is not affected by temperature. Furthermore, since the negative C plate is optimized in the selective reflection wavelength range of 100 nm to 350 nm, light leakage and the like can be remarkably suppressed.

  The specific procedure of the above-mentioned polymerization treatment or crosslinking treatment can be appropriately selected depending on the kind of polymerization initiator and crosslinking agent used. For example, when a photopolymerization initiator or a photocrosslinking agent is used, light irradiation may be performed, and when an ultraviolet polymerization initiator or an ultraviolet crosslinking agent is used, ultraviolet irradiation may be performed. When a cross-linking agent is used, heating may be performed. The irradiation time, irradiation intensity, total irradiation amount, and the like of light or ultraviolet light can be appropriately set according to the type of liquid crystal material, the type of substrate, the characteristics desired for the negative C plate, and the like. Similarly, the heating temperature, the heating time, and the like can be appropriately set according to the purpose.

  The first negative C plate formed as described above is preferably subjected to an orientation treatment on the surface opposite to the substrate. By performing the alignment treatment, a first optical compensation layer having desired optical characteristics can be formed on the surface of the first negative C plate by coating. As the alignment treatment applied to the negative C plate, any appropriate alignment treatment is used as long as the appropriate liquid crystal panel and liquid crystal display device of the present invention are obtained. Examples thereof include rubbing treatment, oblique vapor deposition method, stretching treatment, photo-alignment treatment, magnetic field alignment treatment, and electric field alignment treatment. Preferably, a rubbing process is used. This alignment treatment may be performed directly on the surface of the negative C plate, or any suitable alignment film may be formed and applied to the alignment film. Preferably, any appropriate alignment film is subjected to an alignment treatment. As the alignment film, for example, a silane coupling agent layer, a polyvinyl alcohol layer, or a polyimide layer may be used, or a photo-alignment film in which any appropriate polymer layer having a photocrosslinking group is irradiated with polarized ultraviolet rays may be used. Preferably, a polyvinyl alcohol layer or a polyimide layer is used. For example, when a polyvinyl alcohol layer is used for the alignment film, the thickness of the alignment film is about 70 nm. Any appropriate method can be adopted as a method for forming the alignment film as long as the effects of the present invention are not impaired.

  In the rubbing treatment step of rubbing the surface of the long substrate film with a rubbing roll, the rubbing treatment method preferably supports and conveys the long substrate film with a conveying belt having a metal surface, and A plurality of backup rolls are disposed so as to support the lower surface of the conveyance belt that supports the scale substrate film and face the rubbing roll, and the rubbing strength RS defined by the following formula (1) is preferably 800 mm or more, The method is more preferably set to 850 mm or more, further preferably 1000 mm or more, and particularly preferably 2200 mm or more.

  RS = N · M (1 + 2πr · nr / v) (1)

  Here, N is the number of rubbing times (number of rubbing rolls) (dimensionless amount), M is the pushing amount (mm) of the rubbing roll, π is the circumference, r is the radius (mm) of the rubbing roll, nr represents the number of rotations (rpm) of the rubbing roll, and v represents the conveyance speed (mm / sec) of the long base film. As will be described later, when a raised cloth is wound around the rubbing roll, r means the radius (mm) of the rubbing roll including the raised cloth portion.

  According to the above method, (1) when the rubbing treatment is performed, the amount of pushing of the rubbing roll is provided by disposing a plurality of backup rolls that support the lower surface of the conveying belt that supports and conveys the long base film. Can be rubbed in a stable state, even if it is increased (2) Even if the long base film is blocked, it is referred to as “rubbing strength”. It is possible to obtain uniform orientation characteristics (uniform optical characteristics) by setting the parameter value to a predetermined value or more. (3) Continuous rubbing treatment on a long base film by a roll-to-roll method Therefore, low cost can be realized. The “rubbing roll push-in amount” in the above method means that the rubbing roll first contacts the surface of the long base film when the position of the rubbing roll is changed with respect to the surface of the long base film. This position is the origin (0 point), which means the amount (position variation) of pushing the rubbing roll from the origin toward the long base film. As will be described later, when a raised cloth is wound around a rubbing roll, the position where the bristles of the raised cloth wound around the rubbing roll first contact the surface of the long base film is the origin (0 Point).

  In the rubbing treatment method, when the rubbing treatment is performed, a plurality of rod-shaped backup rolls supporting the lower surface of the conveying belt that supports and conveys the long base film is disposed substantially in parallel with each other, thereby The flatness of the conveyor belt supported by the roll is likely to increase. In this case, when the distance between adjacent backup rolls is set to be smaller than 50 mm, the external shape of the backup roll must be reduced. In this case, if the conveying speed of the long base film is constant, the backup roll will rotate at high speed during the rubbing process compared to the case where the outer diameter of the backup roll is large, and the heat generated at this time There is a possibility that problems such as deformation of the long base film supported by the conveyor belt may occur. On the other hand, when the distance between adjacent backup rolls is set to be larger than 90 mm, the flatness of the conveyor belt is lowered, thereby causing a problem of uneven orientation and an appearance defect. Therefore, in order to avoid such a problem, the distance between the axes of the adjacent backup rolls is preferably set to 50 mm or more and 90 mm or less, and more preferably set to 60 mm or more and 80 mm or less. According to this preferred configuration, it is possible to impart even more uniform orientation characteristics to the long base film, and thus, it is possible to form an optical compensation layer having even more uniform optical characteristics. .

  When the outer diameter (diameter) of the backup roll is set to be smaller than 30 mm, when the conveyance speed of the long base film is constant, the rubbing process is performed as compared with the case where the outer diameter of the backup roll is large. The backup roll rotates at a high speed, and the heat generated at this time may cause problems such as deformation of the long base film supported by the conveyor belt. On the other hand, when the outer diameter of the backup roll is set to be larger than 80 mm, there is a problem that orientation unevenness occurs due to a decrease in the flatness of the conveyor belt, and appearance defects tend to occur. Therefore, in order to avoid such a problem, the outer diameter of the backup roll is preferably set to 30 mm or more and 80 mm or less, and more preferably set to 40 mm or more and 70 mm or less.

  In the present invention, a brushed cloth is preferably wound around the rubbing roll. As the raised cloth, for example, any one of rayon, cotton, nylon, and a mixture thereof is preferably used.

  The thickness of the conveyor belt is preferably in the range of 0.5 to 2.0 mm, more preferably in the range of 0.7 to 1.5 mm in order to impart flexibility while preventing it from being easily slackened. is there.

  Hereinafter, an example of the rubbing method will be described with reference to the drawings.

  FIG. 9 is a perspective view showing a schematic configuration of a rubbing processing apparatus for carrying out the rubbing processing method. As shown in FIG. 9, the rubbing treatment apparatus includes a drive roll 1 and 2, a transport belt 3 that is installed between the drive rolls 1 and 2 and supports and transports the long base film F, and A rubbing roll 4 disposed so as to be vertically movable above and below the conveyor belt 3 and a lower surface of the conveyor belt 3 that supports the long base film F are supported and disposed so as to face the rubbing roll 4. A plurality (five in this example) of rod-like backup rolls 5 are provided. In addition, you may install an appropriate static elimination apparatus, a dust removal apparatus, etc. before and behind a rubbing processing apparatus as needed. In the present invention, the rubbing apparatus preferably has 2 to 6 backup rolls.

The conveyor belt 3 is a metal surface (the entire conveyor belt 3 may be made of metal) having a mirror-finished surface that supports the long base film F. As such a metal, various metal materials such as copper and steel can be used, but stainless steel is preferably used from the viewpoint of strength, hardness, and durability. In order to ensure adhesion with the long base film F, it is preferable to set the arithmetic average surface roughness Ra (JIS B 0601 (1994 version)) to 0.02 μm or less as the degree of mirror finish. Preferably it is 0.01 micrometer or less. Moreover, in order to prevent the slack of the long base film F, it is necessary to prevent the transport belt 3 that supports it from being slack. In view of the fact that it is necessary to give a certain degree of flexibility in order to prevent the conveyance belt 3 from slacking and to be installed between the drive rolls 1 and 2, the thickness of the conveyance belt 3 is 0.5-2. It is preferable to be in the range of 0.0 mm, and more preferably in the range of 0.7 to 1.5 mm. In addition, the tension applied to the conveyor belt 3 is preferably in the range of 0.5 to 20 kg weight / mm ² in consideration of the tension strength of the conveyor belt 3 while preventing the slack of the conveyor belt 3. Preferably, the range is ^{2 to} 15 kgf / mm ² .

  As for the rubbing roll 4, it is preferable that the raising cloth is wound by the outer peripheral surface. What is necessary is just to select suitably the material, shape, etc. of a raising cloth according to the material of the elongate base film F which is rubbed. Generally, rayon, cotton, nylon, or a mixture thereof can be applied as a raised cloth. The rotation axis of the rubbing roll 4 according to this example is inclined (for example, an inclination angle of 0 to 50 degrees) from a direction perpendicular to the conveyance direction of the long base film F (the direction indicated by the arrow in FIG. 9). That is, it can be set to an arbitrary axial angle with respect to the long side (longitudinal direction) of the long base film F. Moreover, the rotation direction of the rubbing roll 4 can be appropriately selected according to the conditions of the rubbing treatment.

  As described above, the plurality of backup rolls 5 are disposed so as to support the lower surface of the conveyance belt 3 that supports the long base film F and to face the rubbing roll 4. Since the plurality of backup rolls 5 are disposed, the rubbing roll 4 can be rubbed in a stable state even when the rubbing roll 4 is pushed in an inclined state or when the pushing amount of the rubbing roll 4 is increased. Processing can be performed.

  When the rubbing process is performed on the long base film F using the rubbing apparatus, the long base film F wound around a predetermined roll (not shown) has a plurality of transport rolls (not shown). Then, the toner is supplied onto the conveyor belt 3. And by rotating the drive rolls 1 and 2, the upper part of the conveyance belt 3 moves in the direction shown by the arrow in FIG. 9, and accordingly, the long base film F is also conveyed together with the conveyance belt 3, A rubbing process is performed by the rubbing roll 4.

  In the rubbing treatment step of this example, the rubbing strength RS defined by the following formula (1) is preferably set to 800 nm or more, more preferably 850 nm or more, further preferably 1000 nm or more, and particularly preferably 2200 nm or more. Yes.

  RS = N · M (1 + 2πr · nr / v) (1)

  10 is a front view partially showing the rubbing treatment apparatus shown in FIG. 9, FIG. 10 (a) is a front view of the vicinity of the rubbing roll 4, and FIG. 10 (b) is a rubbing roll 4 and a long base material. It is a front view which expands and shows the contact location vicinity with the film F surface. As described above, in the above formula (1), N is the number of rubbing times (corresponding to the number of rubbing rolls 4, 1 in this example) (dimensionless amount), and M is the pushing amount (mm) of the rubbing roll 4. , Π is the circumference, r is the radius (mm) of the rubbing roll 4 (including the raised cloth 4a), nr is the number of revolutions (rpm) of the rubbing roll, v is the conveyance speed of the long base film F (Mm / sec). Note that the pushing amount M of the rubbing roll is wound around the rubbing roll 4 when the position of the rubbing roll 4 is changed with respect to the surface of the long base film F as shown in FIG. The position where the bristles of the raised cloth 4a first contact the surface of the long base film F (the position indicated by the broken line in FIG. 10B) is the origin (0 point), and the long base film F from the origin. Means the amount of pushing the rubbing roll 4 toward the position (the amount pushed to the position shown by the solid line in FIG. 10B).

  As described above, even when the rubbing strength RS is set to preferably 800 nm or more, more preferably 850 nm or more, further preferably 1000 nm or more, and particularly preferably 2200 nm or more, blocking occurs in the long base film F. Even so, uniform alignment characteristics can be imparted, and as a result, an optical compensation layer having uniform optical characteristics can be produced. The long base film F to which the rubbing treatment according to this example is applied is a liquid crystal compound applied to the surface by rubbing the surface or by rubbing an alignment film formed on the surface. As long as a function capable of orienting is provided, the material is not particularly limited, and the above-described long base film can be applied.

  As long as the rubbing strength RS is set to preferably 800 nm or more, more preferably 850 nm or more, further preferably 1000 nm or more, and particularly preferably 2200 nm or more, other rubbing treatment conditions (each parameter) can be arbitrarily selected. Yes, the conveyance speed v of the long base film F is, for example, preferably in the range of 1-50 m / min, more preferably in the range of 1-10 m / min, and the rotation speed nr of the rubbing roll 4 is, for example, The pushing amount M of the rubbing roll 4 is, for example, preferably in the range of 100 to 2000 μm, and more preferably in the range of 100 to 1000 μm.

  In this example, as a preferable configuration, for the plurality of rod-shaped backup rolls 5 arranged substantially parallel to each other, the distance between the axes of the adjacent backup rolls 5 (L1 to L4 in FIG. 10A) is Preferably it is set to 50 mm or more and 90 mm or less, More preferably, it is set to 60 mm or more and 80 mm or less. With such a configuration, the flatness of the transport belt 3 supported by the backup roll 5 is likely to increase. Further, since the inter-axis distances L1 to L4 are set to 50 mm or more (thus, the outer diameter of the backup roll 5 inevitably increases to some extent), the backup roll 5 does not rotate at high speed during the rubbing process. Due to the heat generated at this time, problems such as deformation of the long base film F supported by the conveyor belt 3 hardly occur. Furthermore, since the inter-axis distances L1 to L4 are set to 90 mm or less, the flatness of the transport belt 3 is not lowered, and uniform orientation characteristics can be imparted to the long base film F. The outer diameter of each backup roll 5 is preferably set to 30 mm to 80 mm, more preferably 40 mm to 70 mm. By setting the outer diameter of the backup roll 5 to 30 mm or more, the backup roll 5 does not rotate at high speed during the rubbing process, and the long base film F supported on the conveyor belt 3 by the heat generated at this time. Are unlikely to occur. In addition, by setting the outer diameter of the backup roll 5 to 80 mm or less, uniform orientation characteristics can be imparted to the long base film F without lowering the flatness of the transport belt 3. In this example, the case where the backup roll 5 is a rod-shaped roll has been described as an example. However, the present invention is not limited to this, and the backup roll 5 includes a plate (bearing plate) having a plurality of spherical bodies. ) Can also be applied.

  The direction of the alignment treatment is a direction that forms a predetermined angle with the absorption axis of the polarizer when the polarizers are stacked. This orientation direction is substantially the same as the direction of the slow axis of the optical compensation layer to be formed. Therefore, the predetermined angle is preferably + 40 ° to + 50 ° or −40 ° to −50 °, more preferably + 42 ° to + 48 ° or −42 ° to −48 °, and particularly preferably + 44 °. ~ + 46 ° or -44 ° to -46 °.

  The substrate can be peeled from the negative C plate after obtaining a laminate having a polarizer / optical compensation layer / negative C plate in this order. At this time, the polarizer may have a protective layer on at least one surface thereof as necessary.

  In the above representative example of the method for forming the negative C plate, a liquid crystal monomer (for example, a polymerizable monomer or a crosslinkable monomer) is used as a liquid crystal material. It is not limited to such a method, The method using a liquid crystal polymer may be used. However, the method using the liquid crystal monomer as described above is preferable. By using a liquid crystal monomer, a thinner optical compensation layer having a better optical compensation function can be formed. Specifically, if a liquid crystal monomer is used, it is easier to control the wavelength range of selective reflection. Furthermore, since it is easy to set the viscosity and the like of the coating liquid, the formation of a thin negative C plate is further facilitated, and the handleability is extremely excellent. In addition, the surface flatness of the obtained negative C plate is further improved.

G-2-2. Method of Forming from Non-Liquid Crystal Polymer Next, the case of forming a negative C plate using a non-liquid crystal polymer will be described. As the formation method, any appropriate method can be adopted as long as a desired negative C plate can be obtained. Again, for simplicity, only the method of forming the negative C plate on the substrate will be described. A typical method for forming a negative C plate is to prepare a coating liquid in which a non-liquid crystal polymer is dissolved or dispersed in an appropriate solvent, and this coating liquid is subjected to an appropriate alignment treatment as necessary. Apply and dry with heat.

  Examples of the non-liquid crystal polymer include polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide described in the above section C. Any one of these polymers may be used alone. For example, a mixture of two or more kinds having different functional groups such as a mixture of polyaryletherketone and polyamide may be used. Among such polymers, polyimide is particularly preferable because of its high transparency, high orientation, and high stretchability.

  The solvent of the coating solution is not particularly limited, and examples thereof include halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene; Phenols; aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, N-methyl-2 -Ketone solvents such as pyrrolidone; ester solvents such as ethyl acetate and butyl acetate; t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ester Alcohol solvents such as ter, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, 2-methyl-2,4-pentanediol; amide solvents such as dimethylformamide and dimethylacetamide; nitrile solvents such as acetonitrile and butyronitrile Ether solvents such as diethyl ether, dibutyl ether and tetrahydrofuran; carbon disulfide, ethyl cellosolve, butyl cellosolve and the like. Of these, methyl isobutyl ketone is preferred. This is because it exhibits high solubility in non-liquid crystal materials and does not erode the substrate. These solvents may be used alone or in combination of two or more.

  As the concentration of the non-liquid crystalline polymer in the coating solution, any appropriate concentration can be adopted as long as the negative C plate as described above is obtained and coating is possible. For example, the coating liquid preferably contains 5 to 50 parts by weight, more preferably 5 to 40 parts by weight of the non-liquid crystalline polymer with respect to 100 parts by weight of the solvent. A solution having such a concentration range has a viscosity that is easy to apply.

  The coating liquid may further contain various additives such as a stabilizer, a plasticizer, and metals as necessary.

  The said coating liquid may further contain other different resin as needed. Examples of such other resins include various general-purpose resins, engineering plastics, thermoplastic resins, and thermosetting resins. By using such a resin together, it is possible to form a negative C plate having appropriate mechanical strength and durability depending on the purpose. The kind and amount of the different resin added to the coating solution can be appropriately set according to the purpose. For example, such a resin can be added in a proportion of preferably 0 to 50% by mass, more preferably 0 to 30% by mass with respect to the non-liquid crystalline polymer.

The coating amount of the coating liquid containing the liquid crystal composition can be appropriately set according to the concentration of the coating liquid, the target layer thickness, and the like. For example, when the liquid crystal material concentration of the coating liquid is 20% by weight, the coating amount is preferably 0.03 to 0.17 ml, more preferably 0.05 to 0.17 per area (100 cm ² ) of the base material. 0.15 ml, most preferably 0.08 to 0.12 ml.

  Any appropriate base material can be adopted as the base material. Typically, the base material described in the above section G-2-1 may be used.

  Examples of the coating method of the coating liquid include spin coating, roll coating, flow coating, printing, dip coating, casting film formation, bar coating, and gravure printing. Further, in the application, a polymer layer superposition method may be employed as necessary.

  After the coating, for example, the solvent in the solution is evaporated and removed by drying such as natural drying, air drying, and heat drying (for example, 60 to 250 ° C.) to form a negative C plate.

  As for the 1st negative C plate formed on the base material as mentioned above, the orientation process may be given to the surface on the opposite side to a base material. Details of the alignment treatment are as described in the section G-2-1.

  The direction of the alignment treatment is a direction that forms a predetermined angle with the absorption axis of the polarizer when the polarizers are stacked. This orientation direction is substantially the same as the direction of the slow axis of the optical compensation layer to be formed. Therefore, the predetermined angle is preferably + 40 ° to + 50 ° or −40 ° to −50 °, more preferably + 42 ° to + 48 ° or −42 ° to −48 °, and particularly preferably + 44 °. ~ + 46 ° or -44 ° to -46 °.

  The substrate can be peeled from the negative C plate after obtaining a laminate having a polarizer / optical compensation layer / negative C plate in this order. At this time, the polarizer may have a protective layer on one surface thereof as necessary.

G-3. Method for Forming Optical Compensation Layer A typical method for forming an optical compensation layer is shown below. This method is not limited to the first optical compensation layer, and the second optical compensation layer can be formed by the same method. The procedure in a typical method for forming the optical compensation layer is as follows. First, a liquid crystal material for forming an optical compensation layer is applied to a negative C plate (described in detail in the above section C), and the liquid crystal material is aligned on the negative C plate. Specifically, a coating liquid in which a liquid crystal material is dissolved or dispersed in an appropriate solvent is prepared, and this coating liquid may be applied to the surface subjected to the alignment treatment of the negative C plate. The alignment of the liquid crystal material is performed by processing at a temperature showing a liquid crystal phase according to the type of the liquid crystal material used. By performing such temperature treatment, the liquid crystal material takes a liquid crystal state, and the liquid crystal material is aligned according to the alignment direction of the negative C plate surface. Thereby, an optical compensation layer is formed. By applying a liquid crystal material to the negative C plate to form an optical compensation layer, it is not necessary to use an adhesive, a pressure sensitive adhesive, or the like between the negative C plate and the optical compensation layer. As a result, the present invention can greatly contribute to the thinning of the liquid crystal panel.

  The content of the liquid crystal material in the coating liquid can be appropriately set according to the type of the liquid crystal material, the target layer thickness, and the like. Specifically, the content of the liquid crystal material is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, and most preferably 15 to 30% by weight.

The coating amount of the coating liquid can be appropriately set according to the concentration of the coating liquid, the thickness of the target layer, and the like. For example, when the concentration of the liquid crystal material in the coating solution is 20% by weight, the coating amount is preferably 0.02 to 0.08 ml, more preferably 0.03 to 0.03 to 0.08 ml per area (100 cm ² ) of the substrate. 0.07 ml, most preferably 0.04 to 0.06 ml.

  Any appropriate method can be adopted as the coating method. Specific examples include a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, an extrusion method, a curtain coating method, and a spray coating method.

  The alignment of the liquid crystal material is performed by processing at a temperature showing a liquid crystal phase according to the type of the liquid crystal material used. By performing such temperature treatment, the liquid crystal material takes a liquid crystal state, and the liquid crystal material is aligned according to the alignment direction of the negative C plate surface. Thereby, an optical compensation layer is formed.

  As described above, the treatment temperature can be appropriately determined according to the type of the liquid crystal material. Preferably, it is carried out in the same manner as described in the above section G-2.

  In addition, when the liquid crystal monomer (polymerizable monomer and crosslinkable monomer) described in the above section B is used as the liquid crystal material, the layer formed by the coating may be further subjected to polymerization treatment or crosslinking treatment. preferable. By performing the polymerization treatment, the liquid crystal monomer is polymerized, and the liquid crystal monomer is fixed as a repeating unit of the polymer molecule. Further, by performing the crosslinking treatment, the liquid crystal monomer forms a three-dimensional network structure, and the liquid crystal monomer is fixed as a part of the crosslinked structure. As a result, the alignment state of the liquid crystal material is fixed.

  The specific procedure of the above-mentioned polymerization treatment or crosslinking treatment can be appropriately selected depending on the kind of polymerization initiator and crosslinking agent used. For example, when a photopolymerization initiator or a photocrosslinking agent is used, light irradiation may be performed, and when an ultraviolet polymerization initiator or an ultraviolet crosslinking agent is used, ultraviolet irradiation may be performed. When a cross-linking agent is used, heating may be performed. Light or ultraviolet irradiation time, irradiation intensity, total irradiation amount, and the like can be appropriately set according to the type of liquid crystal material, the type of base material and the type of alignment treatment, the characteristics desired for the optical compensation layer, and the like. Similarly, the heating temperature, the heating time, and the like can be set as appropriate.

  In practice, the surface of the optical compensation layer opposite to the negative C plate may be covered with any suitable separator until the polarizer or protective layer is attached. Contamination can be prevented by having a separator. The separator can be formed by, for example, a method of providing a release coat with a release agent such as silicone-based, long-chain alkyl-based, fluorine-based, molybdenum sulfide, or the like on any appropriate film as necessary.

G-4. Specific Manufacturing Procedure An example of a specific procedure of the manufacturing method of the present invention will be described with reference to FIGS. 5 to 8 of the liquid crystal panel, reference numerals 111, 112, 112 ′, 113, 114, and 115 are rolls for winding a film and / or a laminated body forming each layer.

  In the following description of the specific procedure of the manufacturing method, an example of the liquid crystal panel of the present invention (the liquid crystal panel as shown in FIGS. 1 and 2) will be described. In this liquid crystal panel, the first polarizer is disposed on the viewing side of the liquid crystal cell, the absorption axis direction of the first polarizer is substantially parallel to the longitudinal direction of the liquid crystal cell, and the second polarizer Is disposed on the opposite side to the viewing side of the liquid crystal cell, and the absorption axis direction of the second polarizer is substantially orthogonal to the absorption axis of the first polarizer. Further, the slow axis of the first optical compensation layer and the slow axis of the second optical compensation layer are substantially orthogonal. Although the case where the negative C plate is formed of a cholesteric alignment solidified layer will be described here, the case where the negative C plate is formed of a non-liquid crystal polymer is performed in substantially the same manner. For simplicity, only the method for forming the negative C plate on the substrate will be described.

  First, a long polymer film as a raw material for a polarizer is prepared, and dyeing, stretching, and the like are performed as described in the above section D. Stretching is continuously performed in the longitudinal direction of a long polymer film. Thereby, as shown in the perspective view of FIG. 5, a long first polarizer 11 having an absorption axis in the longitudinal direction (stretching direction: arrow A direction) is obtained.

  As shown in the schematic diagram of FIG. 6, the long protective layer 51 ′, the first polarizer 11, and the long first protective layer 51 are sent out in the direction of the arrows, and the respective longitudinal directions are aligned. In this state, the first polarizing plate 130 is formed by bonding with an adhesive or the like (not shown). In addition, in the figure, the code | symbol 122 shows the guide roll for bonding films together (same also in FIG. 8).

  Next, a polyvinyl alcohol layer is formed on the surface of the first negative C plate 31 formed as described in the section G-2 on the side opposite to the substrate 16. As shown in the perspective view of FIG. 7, the surface of the first negative C plate 31 on which a polyvinyl alcohol layer (not shown) is formed is rubbed with a rubbing roll. At this time, the rubbing direction is, for example, a direction of 45 ° with respect to the longitudinal direction of the first negative C plate 31. Accordingly, the first negative C plate having a rubbing direction (in the direction of arrow B, finally corresponding to the slow axis B of the first optical compensation layer 21 in FIG. 2) as shown in the perspective view of FIG. Can be obtained.

  Next, the first optical compensation layer 21 is formed on the surface of the first negative C plate 31 on which the rubbing treatment has been performed, as described in the section G-3. In the first optical compensation layer 21, since the liquid crystal material is aligned along the rubbing direction, the slow axis direction is substantially the same as the rubbing direction of the first negative C plate 31 (the arrow in FIG. 2). B direction). Thus, by arranging the first optical compensation layer on the surface of the first negative C plate without using an adhesive, it is possible to contribute to the thinning of the liquid crystal panel (liquid crystal display device) of the present invention. .

  Next, as shown in FIG. 8A, the first polarizing plate 130 (protective layer 51 ′, first polarizer 11, first protective layer 51) and the obtained laminated body 131 (first optical component). The compensation layer 21, the first negative C plate 31, and the base material 16) are sent out in the directions of the arrows, and bonded together via an adhesive layer (not shown) in a state in which the respective longitudinal directions are aligned to form the laminate 132 ′. Form. Further, as shown in FIG. 8B, the base material 16 is peeled from the laminated body 132 ′, and the first laminated body 132 (the protective layer 51 ′, the first polarizer 11, the first protective layer 51). The first optical compensation layer 21 and the first negative C plate 31) can be obtained. As described above, according to the present invention, the very thin first optical compensation layer and the first negative C plate can be bonded together by so-called roll-to-roll, and the manufacturing efficiency can be remarkably improved. The second laminate can be manufactured in the same manner.

  The first negative C plate side of the obtained first laminate is bonded to one surface of the liquid crystal cell. At this time, for example, the adhesive described in the above section F is used for bonding. Next, similarly to the first stacked body, the second negative C plate side of the second stacked body is bonded to the other surface of the liquid crystal cell. At this time, it arrange | positions so that the absorption axis of a 1st polarizer and the absorption axis of a 2nd polarizer may be substantially orthogonal. Further, the slow axis of the first optical compensation layer and the slow axis of the second optical compensation layer are arranged so as to be substantially orthogonal. Through the above manufacturing process, the liquid crystal panel 100 of the present invention as shown in FIG. 1 is obtained.

H. Liquid Crystal Display Device The liquid crystal panel of the present invention can be used in a liquid crystal display device. Liquid crystal display devices include, for example, OA devices such as personal computer monitors, notebook computers, and copy machines; mobile devices such as mobile phones, watches, digital cameras, personal digital assistants (PDAs), and portable game machines; video cameras, liquid crystal televisions, and electronic devices. Electric appliances for household use such as a range; In-vehicle equipment such as a back monitor, a car navigation system monitor and a car audio; Exhibition equipment such as an information monitor for a commercial store; Security equipment such as a monitoring monitor; It is suitably used for nursing and medical equipment such as monitors.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. The measuring method of each characteristic in an Example is as follows.

(1) Retardation measurement Refractive indexes nx, ny and nz of a sample film are measured by an automatic birefringence measuring device (manufactured by Oji Scientific Instruments Co., Ltd., automatic birefringence meter KOBRA31PR), and in-plane retardation Δnd and thickness direction are measured. The phase difference Rth was calculated. The measurement temperature was 23 ° C. and the measurement wavelength was 590 nm.
2) Measurement of contrast A white image and a black image were displayed on the liquid crystal display device, and the contrast at an azimuth angle of 0 to 360 ° and a polar angle of 0 to 80 ° was measured by a trade name “EZ Contrast 160D” manufactured by ELDIM.

[Example 1]
Production of Polarizing Plate After a commercially available polyvinyl alcohol (PVA) film (manufactured by Kuraray Co., Ltd.) is dyed in an aqueous solution containing iodine, it is uniaxially stretched about 6 times between rolls having different speed ratios in an aqueous solution containing boric acid. Thus, a long polarizer was obtained. At this time, the longitudinal direction of the polarizer was set to the direction of the absorption axis. Using the manufacturing method described in the above section G, a protective layer (commercial TAC film; manufactured by Fuji Photo Film Co., Ltd.) is bonded to both sides of this polarizer via a PVA adhesive to obtain a polarizing plate having a total thickness of 100 μm. It was. Two polarizing plates were used as a first polarizing plate and a second polarizing plate.

Formation of negative C plate Formation of first negative C plate Polymerizable liquid crystal material (liquid crystal monomer) exhibiting a nematic liquid crystal phase (manufactured by BASF: trade name Paliocolor LC242: represented by the following formula (1)) 90 parts by weight, chiral agent (manufactured by BASF) : Trade name Paliocolor LC756: 10 parts by weight (represented by the following formula (4)), 5 parts by weight of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals: trade name Irgacure 907), and 300 parts by weight of methyl ethyl ketone are uniformly mixed. A coating liquid containing a liquid crystal composition was prepared. A coating liquid containing this liquid crystal composition is coated on a substrate (biaxially stretched PET film) by a spin coating method, heat-treated at 80 ° C. for 3 minutes, and then irradiated with ultraviolet rays (20 mJ / cm ² , wavelength 365 nm). Then, a long negative C plate (cholesteric alignment solidified layer) having a refractive index distribution of nx = ny> nz was formed on the substrate. The thickness of the first negative C plate was 2.4 μm, the in-plane retardation Re _1C was 0 nm, and the thickness direction retardation Rth _1C was 135 nm.

  Next, a 1% by weight polyvinyl alcohol solution was prepared using polyvinyl alcohol having a saponification degree of 99% and a polymerization degree of 2000 (Nippon Synthetic Chemical Co., Ltd .: N-300). The polyvinyl alcohol solution obtained on the surface opposite to the base of the first negative C plate was applied and dried at 120 ° C. for 2 minutes to form an alignment film having a thickness of 70 nm. Next, using a rubbing cloth, an orientation treatment was performed in a predetermined direction (+ 45 ° or −45 °) with respect to the longitudinal direction of the negative C plate. This orientation direction is substantially the same as the direction of the slow axis of the optical compensation layer to be formed. The conditions for the alignment treatment are as follows: rubbing frequency (number of rubbing rolls) is 1, rubbing roll radius r is 76.89 mm, rubbing roll rotation speed nr is 1500 rpm, film transport speed v is 83 mm / sec, rubbing strength RS and indentation amount M was performed under five conditions (a) to (e) as shown in Table 1.

2. Formation of second negative C plate In the same manner as the first negative C plate, a second negative C plate (cholesteric alignment solidified layer) having a refractive index distribution of nx = ny> nz is formed on the substrate. did. The thickness of the second negative C plate was 2.4 μm, the in-plane retardation Re _2C was 0 nm, and the thickness direction retardation Rth _2C was 135 nm. Next, in the same manner as the first negative C plate, an alignment film (polyvinyl alcohol layer) was formed, and an alignment treatment was performed. This orientation direction is substantially the same as the direction of the slow axis of the optical compensation layer to be formed.

Formation of optical compensation layer Formation of the first optical compensation layer 10.0 g of a polymerizable liquid crystal material (liquid crystal monomer) exhibiting a nematic liquid crystal phase (made by BASF: trade name Paliocolor LC242: represented by the above formula (1)), and the polymerizable liquid crystal material 3 g of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd .: trade name Irgacure 907) was dissolved in 40 g of cyclopentanone to prepare a coating liquid containing a liquid crystal material. And after apply | coating the said coating liquid with the bar coater on the 1st negative C plate which performed the orientation process, the liquid crystal was orientated by heat-drying for 2 minutes at 90 degreeC. Under conditions (a) to (c), the alignment state of the liquid crystal was very good. Under conditions (d) and (e), the liquid crystal alignment was slightly disturbed, but it was at a level causing no problem in practical use. The liquid crystal layer is irradiated with light of 1 mJ / cm ² using a metal halide lamp, the polymerizable liquid crystal material is polymerized and the orientation of the liquid crystal layer is fixed, whereby the first optical plate is placed on the first negative C plate. A compensation layer was formed. This first optical compensation layer had a refractive index distribution of nx> ny = nz, a thickness of 1.2 μm, and an in-plane retardation Re ₁ of 140 nm.

2. Formation of Second Optical Compensation Layer A second optical compensation layer was formed on the second negative C plate subjected to the alignment treatment in the same manner as the first optical compensation layer. This second optical compensation layer had a refractive index distribution of nx> ny = nz, a thickness of 1.2 μm, and an in-plane retardation Re ₂ of 140 nm.

Production of laminate 1. Production of first laminated body A laminated body of the first optical compensation layer and the first negative C plate was bonded to the obtained first polarizing plate via an isocyanate-based adhesive (thickness 4 μm). At this time, the first polarizing plate and the first optical compensation layer were bonded so as to face each other. Finally, the base material on which the first negative C plate was supported was peeled off to obtain a first laminate.

2. Production of Second Laminate A second laminate was produced using the same method as the first laminate. At this time, the slow axis of the second optical compensation layer was laminated so as to define an angle of −45 ° with respect to the absorption axis of the second polarizer when viewed from the second polarizer side ( When viewed from the viewing side in FIG. 2, the layers were laminated so as to define an angle of + 45 ° with respect to the absorption axis of the second polarizer.) As a result, when the liquid crystal panel was manufactured, the second optical compensation layer The slow axis was substantially perpendicular to the slow axis of the first optical compensation layer.

Production of Liquid Crystal Panel A VA mode liquid crystal cell was taken out from a Sony PlayStation Portable, and the first laminate was bonded to the viewing side of the liquid crystal cell using an acrylic adhesive (thickness: 20 μm). At this time, the liquid crystal cell and the first negative C plate were arranged to face each other. Next, the second laminate was bonded to the backlight side of the liquid crystal cell using an acrylic pressure-sensitive adhesive (thickness: 20 μm). At this time, the liquid crystal cell and the second negative C plate were arranged to face each other. The absorption axis of the first polarizer is arranged so as to be substantially parallel to the longitudinal direction of the liquid crystal cell, and the absorption axis of the first polarizer and the absorption axis of the second polarizer are substantially the same. So as to be orthogonal to each other. Further, the slow axis of the first optical compensation layer and the slow axis of the second optical compensation layer were arranged so as to be substantially orthogonal. As a result, a liquid crystal panel 1 as shown in FIG. 1 was obtained.

Production of Liquid Crystal Display Device The liquid crystal panel 1 was incorporated into the original liquid crystal display device, the backlight was turned on, and the contrast was measured 10 minutes later. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

[Example 2]
A liquid crystal panel was produced in the same manner as in Example 1 except that the same negative C plate as in Example 1 was used and the negative C plate was directly subjected to alignment treatment without using an alignment film. In addition, when producing the 1st and 2nd laminated body, the triacetyl cellulose film (base material) which supports a negative C plate was peeled. The obtained liquid crystal panel was incorporated into a liquid crystal display device, the backlight was turned on, and the contrast was measured 10 minutes later. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

Example 3
Synthesis from 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (TFMB) The resulting polyimide was dissolved in methyl isobutyl ketone (MIBK) to prepare a 10% by weight polyimide solution. Next, the obtained polyimide solution was applied to a saponified triacetyl cellulose film (base material) and dried at 12 ° C. for 3 minutes to form a negative C plate. The obtained negative C plate had a refractive index distribution of nx = ny> nz, a thickness of 3 μm, an in-plane retardation Re _C of 0 nm, and a thickness direction retardation Rth _C of 135 nm. Two negative C plates were used as the first and second negative C plates.

  A liquid crystal panel was produced in the same manner as in Example 1 except that the negative C plate was used. In addition, when producing the 1st and 2nd laminated body, the triacetyl cellulose film (base material) which supports a negative C plate was peeled. The obtained liquid crystal panel was incorporated into a liquid crystal display device, the backlight was turned on, and the contrast was measured 10 minutes later. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

Example 4
A liquid crystal panel was produced in the same manner as in Example 3, except that the same negative C plate as in Example 3 was used and the negative C plate was directly subjected to the alignment treatment without using the alignment film. In addition, when producing the 1st and 2nd laminated body, the triacetyl cellulose film (base material) which supports a negative C plate was peeled. The obtained liquid crystal panel was incorporated into a liquid crystal display device, the backlight was turned on, and the contrast was measured 10 minutes later. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

Example 5
Formation of optical compensation layer Alignment treatment of protective layer An alignment treatment was performed on the surface of one protective layer (first protective layer) of the polarizing plate obtained in Example 1 using a rubbing cloth. The alignment treatment was performed in a predetermined direction (+ 45 ° or −45 °) with respect to the longitudinal direction of the polarizer. This orientation direction is substantially the same as the direction of the slow axis of the optical compensation layer to be formed.

2. Formation of First Optical Compensation Layer A coating liquid containing a liquid crystal material was prepared in the same manner as in Example 1. A first optical compensation layer is formed on the first protective layer in the same manner as in Example 1 except that the obtained coating liquid is applied onto the first protective layer subjected to the above-described orientation treatment. did. This first optical compensation layer had a refractive index distribution of nx> ny = nz, a thickness of 1.2 μm, and an in-plane retardation Re ₁ of 140 nm. At this time, the slow axis of the first optical compensation layer defines an angle of + 45 ° with respect to the absorption axis of the first polarizer when viewed from the first polarizer side (viewing side). Been formed.

3. Formation of Second Optical Compensation Layer A second optical compensation layer was formed on the second protective layer in the same manner as the first optical compensation layer. At this time, the slow axis of the second optical compensation layer defines an angle of −45 ° with respect to the absorption axis of the second polarizer when viewed from the second polarizer side (backlight side). Formed as follows. (When viewed from the viewing side in FIG. 2, it was formed so as to define an angle of + 45 ° with respect to the absorption axis of the second polarizer.) As a result, when the liquid crystal panel was produced, the second optical The slow axis of the compensation layer was substantially perpendicular to the slow axis of the first optical compensation layer.

Formation of negative C plate and production of laminated body Formation of First Negative C Plate and Production of First Laminate A coating liquid containing a liquid crystal composition was prepared in the same manner as in Example 1. A negative C plate (cholesteric alignment solidified layer) was formed in the same manner as in Example 1 except that this coating solution was applied to the surface of the first optical compensation layer opposite to the first protective layer. 1 was formed on the optical compensation layer. In this way, a first laminate was obtained.

2. Production of Second Laminate A second laminate was obtained in the same manner as the first laminate.

  A liquid crystal panel was produced in the same manner as in Example 1 except that the first laminate and the second laminate were used. The obtained liquid crystal panel was incorporated into a liquid crystal display device, the backlight was turned on, and the contrast was measured 10 minutes later. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

Example 6
1. Formation of optical compensation layer Formation of First Optical Compensation Layer In the same manner as in Example 5, a first optical compensation layer was formed on the first protective layer subjected to the alignment treatment.

3. Formation of second optical compensation layer In the same manner as in Example 5, a second optical compensation layer was formed on the second protective layer subjected to the alignment treatment.

Formation of negative C plate and production of laminated body Formation of first negative C plate and production of first laminate A 10% by weight polyimide solution was prepared in the same manner as in Example 3. A negative C plate was formed on the first optical compensation layer in the same manner as in Example 3 except that this solution was applied to the surface of the first optical compensation layer opposite to the first protective layer. . In this way, a first laminate was obtained.

2. Production of Second Laminate A second laminate was obtained in the same manner as the first laminate.

  A liquid crystal panel was produced in the same manner as in Example 1 except that the above first laminate and second laminate were used. The obtained liquid crystal panel was incorporated into a liquid crystal display device, the backlight was turned on, and the contrast was measured 10 minutes later. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

[Comparative Example 1]
Preparation of first and second optical compensation layers A norbornene resin film (manufactured by Nippon Zeon Co., Ltd .: trade name ZEONOR: thickness 60 μm) was uniaxially stretched at a free end at a stretching temperature of 140 ° C. and a stretching ratio of 1.32. A stretched film (λ / 4 plate) was obtained. This stretched film had a refractive index distribution of nx> ny = nz, a thickness of 54 μm, and an in-plane retardation Re of 140 nm. Two films were used as the first and second optical compensation layers.

Preparation of first and second negative C plates A norbornene-based resin film (manufactured by JSR: trade name Arton: thickness 100 μm) was longitudinally stretched 1.27 times at 175 ° C., and then 1.37 times at 176 ° C. A long negative C plate (thickness: 65 μm) having a refractive index distribution of nx = ny> nz was produced by transverse stretching. The negative C plate had an in-plane retardation Re _C of 0 nm and a thickness direction retardation Rth _C of 110 nm. Two negative C plates were used.

  The first and second optical compensation layers and the first and second negative C plates are used, and the first optical compensation layer and the first negative C plate are made of acrylic adhesive. A liquid crystal panel was produced in the same manner as in Example 1 except that the two optical compensation layers and the second negative C plate were bonded using an acrylic adhesive. The obtained liquid crystal panel was incorporated into a liquid crystal display device, the backlight was turned on, and the contrast was measured 10 minutes later. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

[Comparative Example 2]
A product name “ZEONOR” (Zeonor) (manufactured by ZEON), which is a norbornene-based film, is uniaxially stretched at a fixed end of 1.5 times in the longitudinal direction at 140 ° C. The thickness was 40 μm). When the retardation of the obtained optical compensation film was measured, the relationship of nx>ny> nz was satisfied, the in-plane retardation Re was 140 nm, the thickness direction retardation Rth was 217 nm, and the Nz coefficient (Nz = (nx−nz) / (Nx-ny)) was 1.6. A liquid crystal panel having the polarizing plate used in Example 1, the optical compensation film, the liquid crystal cell used in Example 1, the optical compensation film, and the polarizing plate used in Example 1 in this order was prepared. At this time, an acrylic pressure-sensitive adhesive was used for laminating each layer. This liquid crystal panel was incorporated into a liquid crystal display device, and the contrast was measured 10 minutes after the backlight was turned on. Table 2 shows the obtained characteristics and the thickness of the entire liquid crystal panel.

[Evaluation]
As is clear from Examples 1 to 6 and Comparative Examples 1 and 2, the first and second optical compensation layers are coating layers, and the first and second negative C plates are coating layers. The overall thickness of the liquid crystal panel can be significantly reduced. When Example 1 and Comparative Example 1 were compared, the region having a contrast of 50 or more had the same result, but Example 1 had a thickness of the film portion other than the liquid crystal cell that was about half that of Comparative Example 1, and was thin. Liquid crystal panel could be obtained. Further, Example 1 has a larger polar angle in a region where the contrast is 50 or more than that of Comparative Example 2. From this, it can be seen that the liquid crystal panel of the present invention has excellent contrast in an oblique direction and can be thinned.

    The liquid crystal panel of the present invention can be suitably used for various image display devices (for example, liquid crystal display devices).

It is a schematic sectional drawing of the liquid crystal panel in preferable embodiment of this invention. 1 is a schematic exploded perspective view of a liquid crystal panel in a preferred embodiment of the present invention. It is a general | schematic disassembled perspective view of the liquid crystal panel in another preferable embodiment of this invention. When the liquid crystal display device of this invention employ | adopts a VA mode liquid crystal cell, it is a schematic sectional drawing explaining the orientation state of the liquid crystal molecule of a liquid crystal layer. It is a perspective view which shows the outline of one process in an example of the manufacturing method of the liquid crystal panel of this invention. It is a schematic diagram which shows the outline of another process in an example of the manufacturing method of the elliptically polarizing plate of this invention. It is a perspective view which shows the outline of another process in an example of the manufacturing method of the liquid crystal panel of this invention. It is a schematic diagram which shows the outline of another process in an example of the manufacturing method of the elliptically polarizing plate of this invention. It is a perspective view which shows schematic structure of a rubbing processing apparatus. FIG. 10A is a front view of the vicinity of the rubbing roll, and FIG. 10B is an enlarged front view of the vicinity of the contact portion between the rubbing roll and the surface of the long base film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Drive roll 3 Conveyance belt 4 Rubbing roll 4a Brushed cloth 5 Backup roll F Long base film 11, 12 Polarizer 21, 22 Optical compensation layer 31, 32 Negative C plate 40 Liquid crystal cell 51, 52 Protective layer 100 Liquid crystal Display device

Claims (10)

A liquid crystal cell, a first polarizer disposed on one side of the liquid crystal cell, a second polarizer disposed on the other side of the liquid crystal cell, the first polarizer and the liquid crystal cell A first optical compensation layer and a first negative C plate disposed between the liquid crystal cell and the second polarizer, and a second negative C plate and a second optical layer disposed between the liquid crystal cell and the second polarizer. A compensation layer,
The first optical compensation layer is disposed on the first negative C plate without an adhesive;
The second optical compensation layer is disposed on the second negative C plate without an adhesive;
The first optical compensation layer and the second optical compensation layer are coating layers that function as λ / 4 plates, each having a thickness of 0.3 to 3 μm,
The liquid crystal panel in which the first negative C plate and the second negative C plate are coating layers, each having a thickness of 0.5 to 10 μm.   From the viewing side to the backlight side, the first polarizer, the first optical compensation layer, the first negative C plate, the liquid crystal cell, the second negative C plate, the second optical compensation layer, the second The liquid crystal panel according to claim 1, wherein the polarizers are arranged in this order.   A liquid crystal display device comprising the liquid crystal panel according to claim 1. Forming a first optical compensation layer on a surface of the first negative C plate;
Laminating a first polarizer on the surface of the first optical compensation layer opposite to the first negative C plate to obtain a first laminate;
Bonding the first negative C plate side of the first laminate to one surface of the liquid crystal cell;
Forming a second optical compensation layer on the surface of the second negative C plate;
Laminating a second polarizer on the surface of the second optical compensation layer opposite to the second negative C plate to obtain a second laminate;
Bonding the second negative C plate side of the second laminate to the other surface of the liquid crystal cell,
A method for manufacturing a liquid crystal panel. A step of applying a liquid crystal composition containing a liquid crystal material and a chiral agent to a substrate; and a step of treating the applied liquid crystal composition at a temperature at which the liquid crystal material exhibits a liquid crystal phase. And the substrate is peeled after the first laminate is obtained.
The manufacturing method according to claim 4. The first negative C plate is a step of applying a solution containing at least one non-liquid crystal polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide to the substrate. Formed by a method comprising:
After the first laminate is obtained, the substrate is peeled off.
The manufacturing method according to claim 4. A step of forming an alignment film on a surface opposite to the base of the first negative C plate; and a step of performing an alignment treatment on the surface of the alignment film;
The manufacturing method of Claim 5 or 6. A process in which the second negative C plate is coated with a liquid crystal composition containing a liquid crystal material and a chiral agent on a substrate; and the coated liquid crystal composition is treated at a temperature at which the liquid crystal material exhibits a liquid crystal phase. And the substrate is peeled after the second laminate is obtained.
The manufacturing method in any one of Claim 4 to 7. The second negative C plate is a step of applying a solution containing at least one non-liquid crystal polymer selected from the group consisting of polyamide, polyimide, polyester, polyetherketone, polyamideimide, and polyesterimide to the substrate. Formed by a method comprising:
The substrate is peeled after the second laminate is obtained.
The manufacturing method in any one of Claim 4 to 7. A step of forming an alignment film on a surface opposite to the base of the second negative C plate; and a step of performing an alignment treatment on the surface of the alignment film;
The manufacturing method of Claim 8 or 9.

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