JP2005275321A - Color filter substrate, base material for liquid crystal display, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color filter substrate which has relatively high display characteristics when being used as a material of a liquid crystal panel for display and with which it is made easy to obtain a liquid crystal display device which can maintain desired display characteristics and has a relatively wide temperature range. <P>SOLUTION: On a base material having light transmissivity, a birefringent layer is formed of three-dimensionally bridged polymerizable crystal and on the birefringent layer, a color filter layer is formed to obtain a color filter substrate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color filter substrate having a color filter layer, a liquid crystal display substrate using the color filter substrate, and a liquid crystal display device including the liquid crystal display substrate.

  The liquid crystal display device is attracting attention as a flat panel display because it is easy to reduce the thickness and weight and consumes little power, and it is easy to suppress the occurrence of flicker, and as a display device of a personal computer or a television receiver. As the market is expanding rapidly. In addition, liquid crystal display devices are becoming larger.

  Liquid crystal display devices of various display modes have been developed. Since the liquid crystal has birefringence, the liquid crystal display device of any display mode basically has a viewing angle dependency. A large-sized liquid crystal display device has a wider practical viewing angle than a small-sized liquid crystal display device. Therefore, as the size of the liquid crystal display device increases, the demand for improved viewing angle dependency increases. For this reason, in parallel with the development of liquid crystal display devices, various optical elements that optically compensate for incident light to the liquid crystal cell or light emitted from the liquid crystal cell have been developed in order to improve the viewing angle characteristics.

  As the optical element, conventionally, an optical compensation liquid crystal cell or an optical compensation film made of an optically uniaxial or biaxial stretched resin film has been used. An optical compensation member having a birefringent layer has also been developed.

  For example, Patent Document 1 describes a viewing angle compensation film made of a nematic liquid crystal polymer having a positive intrinsic birefringence value in which molecular chains are aligned in the normal direction of the film surface. Patent Document 2 discloses a side-chain liquid crystal containing a monomer unit containing a liquid crystalline fragment side chain and a monomer unit containing a non-liquid crystalline fragment side chain on a substrate not provided with a vertical alignment film. A method of producing a homeotropic alignment liquid crystal film that can be used as an optical film by applying a polymer, further homeotropically aligning the liquid crystal polymer in a liquid crystal state, and then fixing the liquid crystal polymer while maintaining the alignment state. Is described.

  In Patent Document 3, a binder layer and an anchor coat layer are formed on a substrate in this order, and a specific side chain type liquid crystal polymer is applied to the anchor coat layer to perform homeotropic alignment, and then the homeotropic alignment state is maintained. A method of producing a homeotropic alignment liquid crystal film that can be used as an optical film after being fixed as it is is described.

  In Patent Document 4, a polymer film having an in-plane retardation of 50 nm or less that has not been subjected to an orientation treatment, specifically, an orientation treatment such as surface rubbing treatment or formation of an orientation film has not been conducted, And applying a solution containing a thermotropic liquid crystal compound and exhibiting a cholesteric liquid crystal phase in a liquid crystal state onto a polymer film that has not been subjected to stretching and orientation treatment, and after aligning and curing, to obtain an optical film An optical film manufacturing method is described.

  In any of the viewing angle compensation film, homeotropic alignment liquid crystal film, and optical film described in Patent Literatures 1 to 4, a layer formed using a polymerizable liquid crystal functions as a birefringent layer.

Further, although not intended for optical compensation, Patent Document 5 discloses that an alignment film is formed on a substrate that has not been subjected to uniaxial alignment treatment, and a polymerizable liquid crystal compound, a chiral agent, and A selective reflection member obtained by polymerizing the liquid crystal composition after applying a liquid crystal composition containing an air interface alignment agent is described.
JP-A-5-142531 JP 2002-174725 A JP 2003-121852 A Japanese Patent Laying-Open No. 2003-29037 (refer to the claims and the 0019th stage) Japanese Patent Laying-Open No. 2003-185827 (refer to claims and stages 0047 to 0065)

  However, each of the optical compensation members described in Patent Documents 1 to 4 is used as a retrofitting member. For example, when these optical compensation members are provided on a display liquid crystal panel, a predetermined layer is formed with an adhesive. Since it is affixed on top, the following problems arise. That is, the pressure-sensitive adhesive usually has a refractive index different from that of the underlying layer, which causes a problem that reflection occurs at the interface and the contrast of the display image by the liquid crystal display device is likely to be lowered.

  Moreover, since the homeotropic alignment liquid crystal film obtained by the method described in Patent Document 2 or Patent Document 3 is composed of a side chain type liquid crystal polymer, its birefringence characteristics are easily affected by heat, and the desired birefringence characteristics are obtained. The temperature range that can be maintained is relatively narrow. For this reason, for example, it is difficult to use for a liquid crystal display device that requires relatively high heat resistance such as an in-vehicle liquid crystal display device. The homeotropic alignment liquid crystal film obtained by the method described in Patent Document 2 or Patent Document 3 has a problem that its application is limited.

  The selective reflection member described in Patent Document 5 includes a substrate for a liquid crystal display by providing a transparent electrode with an inorganic transparent electrode material such as ITO (indium tin oxide) on a layer obtained by polymerizing a liquid crystal composition. However, since the difference between the thermal contraction rate of the inorganic transparent electrode material such as ITO and the thermal contraction rate of the above-mentioned layer obtained by polymerizing the liquid crystal composition is relatively large, this selective reflection is possible. The member has the following problems. That is, there is a problem that a large number of cracks are generated in the transparent electrode after the transparent electrode is formed, and the liquid crystal display substrate having desired optical characteristics is difficult to obtain.

  The present invention has been made to solve the above-described problems, and a first object of the present invention is that when used as a material for a liquid crystal display substrate, the display characteristics are relatively high and a desired display is achieved. An object of the present invention is to provide a color filter substrate that makes it easy to obtain a liquid crystal display device having a relatively wide temperature range in which characteristics can be maintained.

  A second object of the present invention is to provide a liquid crystal display device having a relatively wide temperature range in which display characteristics are relatively high and desired display characteristics can be maintained when used as a material for a display liquid crystal panel. An object of the present invention is to provide a substrate for a liquid crystal display that can be easily obtained.

  A third object of the present invention is to provide a liquid crystal display device that has a relatively high display characteristic and that can easily obtain a relatively wide temperature range that can maintain a desired display characteristic.

  The color filter substrate of the present invention that achieves the first object described above includes a base material having optical transparency, a birefringent layer formed on the base material by a three-dimensionally crosslinked polymerizable liquid crystal, and the birefringence layer. And a color filter layer formed on the layer.

  In the color filter substrate of the present invention, since the birefringent layer is formed directly on the base material, the interface reflection is reduced as compared with the case where the birefringent layer is pasted on the base material using an adhesive. In addition, since the birefringent layer is formed by the three-dimensionally crosslinked polymerizable liquid crystal, the temperature range in which desired birefringence characteristics can be maintained is relatively wide. Further, since a color filter layer is formed on this birefringent layer, even if a transparent electrode is formed on the color filter layer with an inorganic transparent electrode material such as ITO in order to obtain a liquid crystal display substrate, the color filter The layer functions as a buffer layer (protective layer), and cracks are suppressed from occurring in the transparent electrode due to a difference in thermal shrinkage between the inorganic transparent electrode material and the birefringent layer after the transparent electrode is formed.

  Therefore, according to the color filter substrate of the present invention, it is easy to obtain a liquid crystal display device having relatively high display characteristics and a relatively wide temperature range capable of maintaining desired display characteristics.

  In the color filter substrate of the present invention, a transparent electrode may be formed on the color filter layer.

  The substrate for a liquid crystal display of the present invention that achieves the second object described above has the color filter substrate of the present invention in which a transparent electrode is formed on a color filter layer, and an alignment film that covers the transparent electrode. Features.

  According to the present invention, since the alignment film is formed on the color filter substrate of the present invention having a transparent electrode, when used as a material for a liquid crystal panel for display, display characteristics are relatively high and desired. It is easy to obtain a liquid crystal display device having a relatively wide temperature range that can maintain the display characteristics.

  The liquid crystal display device of the present invention that achieves the third object described above has a first liquid crystal display substrate located on the display surface side and a second liquid crystal display substrate located on the back side. A liquid crystal display device comprising a liquid crystal panel, wherein one of the first liquid crystal display substrate and the second liquid crystal display substrate is the above-described liquid crystal display substrate of the present invention. And

  According to this invention, since the liquid crystal display panel is configured using the above-described liquid crystal display substrate of the present invention, the display characteristics are relatively high, and the temperature at which the desired display characteristics can be maintained. It becomes easy to provide a liquid crystal display device having a relatively wide range.

  According to the present invention, (1) when used as a material for a liquid crystal display substrate, a liquid crystal display device having relatively high display characteristics and a relatively wide temperature range capable of maintaining desired display characteristics. (2) When used as a material for a liquid crystal panel for display, a temperature range in which display characteristics are relatively high and desired display characteristics can be maintained is relatively high A substrate for a liquid crystal display that makes it easy to obtain a wide liquid crystal display device, or (3) a substrate that has a relatively high display characteristic and a relatively wide temperature range that can maintain a desired display characteristic. Since an easy liquid crystal display device is provided, it is easy to provide a liquid crystal display device that has relatively high display characteristics and can be used for various applications.

  Hereinafter, the embodiments of the color filter substrate of the present invention, the substrate for liquid crystal display of the present invention, and the liquid crystal display device of the present invention will be described in detail with reference to the drawings as appropriate.

<Color filter substrate (first form)>
FIG. 1 is a schematic view showing an example of a basic cross-sectional structure of a color filter substrate of the present invention. The color filter substrate 30 shown in the figure includes a light-transmitting base material 10, a birefringent layer 15 formed on the base material 10 by three-dimensionally crosslinked polymerized liquid crystal, and a light-shielding layer formed on the birefringent layer 15. (Black matrix) 20 and a color filter layer 25 formed on the birefringent layer 15.

  As the base material 10, a plate-like material, a sheet-like material, or a film-like material formed by an inorganic material having a desired light transmittance, an organic material, or a laminate of an inorganic material layer and an organic material layer is used. Can do. Whether the substrate 10 has a single-layer structure or a laminated structure can be appropriately selected according to the orientation of the polymerizable liquid crystal in the birefringent layer 15, the flexibility required for the color filter substrate 30, and the like. The light transmittance of the substrate 10 can be appropriately selected according to the light transmittance required for the color filter substrate 30.

  The birefringent layer 15 formed on the substrate 10 controls the polarization state of light transmitted through the liquid crystal layer to a desired state when the color filter substrate 30 is used as a material for a display liquid crystal panel. And is formed of a polymerizable liquid crystal as described above. The orientation of the polymerizable liquid crystal in the birefringent layer 15 depends on the birefringence characteristics required for the birefringent layer 15, homeotropic orientation, planar cholesteric orientation (hereinafter, simply referred to as “cholesteric orientation”), and homogeneous. An orientation, a hybrid orientation, a tilted orientation, or the like can be used.

  When the polymerizable liquid crystal is homeotropically aligned, the birefringent layer 15 has a uniaxial property in which the refractive index in the thickness direction is larger than the in-plane refractive index. It functions as a birefringent layer (so-called “+ C plate”). When the polymerizable liquid crystal is cholesterically oriented, the birefringent layer 15 has a uniaxial birefringence having an optical axis in the thickness direction of the layer and a refractive index in the thickness direction smaller than the in-plane refractive index. It functions as a refractive layer (so-called “-C plate”). When the polymerizable liquid crystal is homogeneously aligned, the birefringent layer 15 functions as a uniaxial birefringent layer (so-called “+ A plate”) having an optical axis in the plane. When the polymerizable liquid crystal is hybrid or tilted, the birefringent layer 15 functions as a birefringent layer in which the refractive index ellipsoid is tilted. Details of the birefringent layer 15 will be described later.

  The light-shielding layer (black matrix) 20 formed on the birefringent layer 15 is used for leakage of light from the pixels in the display liquid crystal panel (leakage light), and for active elements in the active matrix drive type display liquid crystal panel. This is to prevent light deterioration and the like, and each pixel is defined in a plan view in the display liquid crystal panel.

  The light shielding layer 20 can be formed by patterning a metal thin film having a light shielding property or light absorbing property, such as a metal chromium thin film or a tungsten thin film, into a predetermined shape. In order to suppress the occurrence of cracks in the light shielding layer 20, it is preferable to use a color resin colored with a black pigment and three types of color resins that become black by additive color mixing or subtractive color mixing. In addition, it is also possible to use a monochromatic color filter layer as the color filter layer 25. In this case, the light shielding layer 20 may be omitted.

  The color filter layer 25 makes it possible to perform color display with the display liquid crystal panel when the color filter substrate 30 is used as a material for the display liquid crystal panel. A primary color system in which a red color filter 25R, a green color filter 25G, and a blue color filter 25B are arranged in a predetermined pattern. Various types of color filter layers called a stripe type, a mosaic type, a triangle type, and the like are known depending on the arrangement of the color filters 25R, 25G, and 25B for each color. Instead of the primary color filter layer 25, a complementary color filter layer may be used.

  The color filter layer 25 is formed, for example, by patterning a color resin coating film as a material for each color filter 25R, 25G, 25B into a predetermined shape by, for example, a photolithography method, or for each color filter Each of 25R, 25G, and 25B can be formed by applying color filter ink, which is a material thereof, in a predetermined shape. The color filters 25R, 25G, and 25B for the respective colors are arranged so as to cover predetermined pixels defined by the light shielding film 20 in plan view.

  In the color filter substrate 30 having the above-described configuration, since the number of interfaces is smaller than when a birefringent layer having a predetermined birefringence characteristic is pasted on the base material 10 using an adhesive, interface reflection is reduced. The In addition, since the birefringent layer 15 is formed by three-dimensionally crosslinked polymerizable liquid crystal, the temperature range in which desired birefringence characteristics can be maintained is relatively wide. Further, since the color filter layer 25 is formed on the birefringent layer 15, even if a transparent electrode is formed on the color filter layer 25 by using an inorganic transparent electrode material such as ITO in order to obtain a liquid crystal display substrate. The color filter layer 25 functions as a buffer layer (protective layer) and suppresses cracks in the transparent electrode due to the difference in thermal shrinkage between the inorganic transparent electrode material and the birefringent layer 15 after the transparent electrode is formed. Is done.

  Therefore, by using this color filter substrate 30 as a material for a liquid crystal display substrate, and further using this liquid crystal display substrate as a material for a display liquid crystal panel, the display characteristics are relatively high and desired display characteristics. It is easy to obtain a liquid crystal display device having a relatively wide temperature range in which the above can be maintained.

  The birefringence characteristics of the birefringent layer 15 can be appropriately selected according to the operation mode of the display liquid crystal panel to be manufactured using the color filter substrate 30. Depending on the birefringence characteristics required for the birefringent layer 15, the type of polymerizable liquid crystal used to form the birefringent layer 15, the orientation of the polymerizable liquid crystal in the birefringent layer 15, and the like are appropriately selected.

  For example, the birefringent layer 15 functioning as a + C plate can be formed by orienting a polymerizable liquid crystal having a rod-like molecular shape perpendicular to the surface of the substrate 10. The birefringent layer 15 functioning as a -C plate, for example, aligns a rod-like polymerizable liquid crystal with cholesteric alignment, or aligns a disc-shaped polymerizable liquid crystal parallel to the surface of the substrate 10. Can be formed. The birefringent layer 15 functioning as a + A plate can be formed, for example, by aligning a polymerizable liquid crystal having a rod-like molecular shape parallel to the surface of the substrate 10 and aligned in the same direction. The birefringent layer 15 that functions as a birefringent layer in which the refractive index ellipsoid is tilted can be formed, for example, by hybrid alignment or tilt alignment of a polymerizable liquid crystal having a rod-like molecular shape.

  Regardless of the birefringence characteristics of the birefringent layer 15, in order to obtain the birefringent layer 15 having relatively high heat resistance, the polymerizable liquid crystal may be three-dimensionally crosslinked as described above. preferable. The birefringent layer 15 in which the polymerizable liquid crystal is three-dimensionally cross-linked uses a polymerizable liquid crystal in which each molecule has two or more polymerizable functional groups (hereinafter referred to as “polyfunctional polymerizable liquid crystal”), or is multifunctional. It can be formed using a mixture of a polymerizable liquid crystal and a polymerizable liquid crystal in which each molecule has only one polymerizable functional group (hereinafter referred to as “monofunctional polymerizable liquid crystal”). By using the polyfunctional polymerizable liquid crystal and the monofunctional polymerizable liquid crystal in combination, the alignment property of the entire polymerizable liquid crystal can be improved or decreased, so that the alignment property of the entire polymerizable liquid crystal can be easily controlled.

  Specific examples of the polyfunctional polymerizable liquid crystal having a rod-like molecular shape include the polymerizable liquid crystals represented by the formulas (I) to (V) shown in FIGS. 2 (a) to 2 (e). Specific examples of the monofunctional polymerizable liquid crystal having a rod shape include the polymerizable liquid crystals represented by the formulas (i) to (iv) shown in FIGS. 2 (f) to 2 (i). Note that n in the formulas (I) to (V) and the formulas (i) to (iv) shown in FIGS. 2 (a) to 2 (e) is a numerical value of 4 to 8.

  In addition, specific examples of the polyfunctional polymerizable liquid crystal having a disk-like molecular shape include those described in, for example, JP-A-8-27284 and those described in JP-A-2001-27706. Specific examples of the monofunctional polymerizable liquid crystal having a disk-like molecular shape include those described in, for example, JP-A-8-27284.

  The birefringent layer 15 is formed, for example, by forming a coating film of the coating composition containing at least the above-described polymerizable liquid crystal and removing the solvent component in the coating film to form a polymerizable liquid crystal layer. It is obtained by aligning the polymerizable liquid crystal in a desired form and three-dimensionally crosslinking the polymerizable liquid crystal in this state. When forming the birefringent layer 15 in which the polymerizable liquid crystal is cholesterically oriented, a chiral agent is used as an essential component in preparing the coating composition. By using a polymerizable chiral agent as the chiral agent, the birefringent layer 15 having relatively high heat resistance can be easily obtained. The above-mentioned coating composition can contain a photopolymerization initiator, a sensitizer, a polyfunctional monomer, and the like as necessary. By containing a polyfunctional monomer, the crosslinkability of the birefringent layer 15 can be improved. It is also possible to form the birefringent layer 15 by a transfer method.

  In aligning the polymerizable liquid crystal in the polymerizable liquid crystal layer, the temperature is equal to or higher than the temperature at which the polymerizable liquid crystal becomes a liquid crystal phase and lower than the temperature at which it becomes an isotropic phase (liquid phase). The polymerizable liquid crystal layer is heated up to “crosslinking temperature”. The method for heating the polymerizable liquid crystal layer to the first crosslinking temperature is not particularly limited, and can be appropriately selected from atmospheric heating, infrared heating, and the like. In order to align the polymerizable liquid crystal, the electric field or magnetic field in a predetermined direction can be applied to the polymerizable liquid crystal layer heated to the first crosslinking temperature.

  The atmosphere when the polymerizable liquid crystal is three-dimensionally cross-linked can be appropriately selected according to the alignment form of the polymerizable liquid crystal. For example, an air atmosphere can be used when the polymerizable liquid crystal is homogeneously aligned, but an inert gas atmosphere is preferable when the polymerizable liquid crystal is homeotropically aligned. The three-dimensional crosslinking of the polymerizable liquid crystal can be performed by, for example, heating the polymerizable liquid crystal layer to the first crosslinking temperature in a desired atmosphere while emitting light having a photosensitive wavelength of the polymerizable liquid crystal, the photopolymerization initiator, or the sensitizer. This can be done by irradiating the polymerizable liquid crystal layer. Regardless of the orientation of the polymerizable liquid crystal, the crosslinking reaction is partially advanced while heating the polymerizable liquid crystal layer to the first crosslinking temperature in an air atmosphere, and then the air atmosphere is lowered to a temperature lower than the first crosslinking temperature. The polymerizable liquid crystal can also be three-dimensionally cross-linked by cooling in, and allowing the cross-linking reaction to proceed again in this state.

  In order to obtain a color filter substrate 30 suitable as a material for a liquid crystal display substrate, it is desirable to reduce the haze in the birefringent layer 15 as much as possible. For example, NDH-2000 (trade name) manufactured by Nippon Denshoku Industries Co., Ltd. Is preferably about 5% or less, more preferably 1% or less.

  In order to obtain the birefringent layer 15 having a small haze, it is desirable to increase the degree of orientation of the polymerizable liquid crystal in the process of forming the birefringent layer 15. Therefore, the coating composition may be polymerized as necessary. It is preferable to contain a compound (hereinafter referred to as “alignment control agent”) capable of controlling the degree of alignment order of the crystalline liquid crystal. In order to align the polymerizable liquid crystal into a desired form, the polymerizable liquid crystal has to be heated once to the liquid crystal phase (nematic phase). Therefore, the alignment control agent has heat resistance not to be decomposed at this time. It is necessary to be. Further, since it is added to the polymerizable liquid crystal, it is preferably soluble in an organic solvent.

  As the alignment control agent, for example, a surfactant or a coupling agent can be used. In the case of forming the birefringent layer 15 in which the polymerizable liquid crystal is homeotropically aligned, a highly water- or oil-repellent surfactant (for example, having a long-chain alkyl group having 3 to 20 carbon atoms). A surfactant, a surfactant having a side chain and containing a fluorine atom in the side chain, or a coupling agent having a strong water or oil repellency (for example, a silane coupling agent having a fluorinated alkyl group) It is preferable to use a silane coupling agent such as When forming the birefringent layer 15 in which the polymerizable liquid crystal is homogeneously aligned, cholesteric aligned, or hybrid aligned, it is preferable to use a surfactant that promotes alignment of the liquid crystal at the free interface.

  When the surfactant is contained in the coating composition, the content varies depending on the type of the surfactant used, but is about 0.001 to 5% by weight with respect to the total amount of the polymerizable liquid crystal. It can select suitably in the range, It is preferable to select suitably in the range of about 0.001-1 weight%.

  Further, when a coupling agent is contained in the coating composition, the content varies depending on the type of coupling agent used, etc., but is 0.001 to 5% by weight based on the total amount of the polymerizable liquid crystal. It can select suitably within the range of about, and it is preferable to select suitably within the range of about 0.01 to 1 weight%.

  The degree of alignment order of the polymerizable liquid crystal in the birefringent layer 15 can be improved by using an alignment film in addition to using the alignment control agent described above. In this case, a substrate having an alignment film is used as the substrate 10 having optical transparency.

  FIG. 3A is a schematic diagram illustrating an example of a basic cross-sectional structure of the color filter substrate 40 using the base material 10 </ b> A having the alignment film 5. The color filter substrate 40 is formed on the light transmissive substrate 1 (however, in addition to the plate-like material, it may be a sheet-like material or a film-like material) and one surface of the light transmissive substrate 1. The alignment film 5 is different from the color filter substrate 30 shown in FIG. 1 in that a base material 10A is formed and a birefringent layer 15 is formed on the alignment film 5. Since the other configuration of the color filter substrate 40 is the same as the configuration of the color filter substrate 30, among the components shown in FIG. 3A, those common to the components shown in FIG. The same reference numerals as those used are assigned, and the description thereof is omitted.

  As said alignment film 5, according to the alignment form of the polymerizable liquid crystal in the birefringent layer 15, for example, a resin horizontal alignment film capable of horizontally aligning the liquid crystal, or vertically aligning the liquid crystal It is possible to use a vertical alignment film made of resin. The vertical alignment film can also be formed using the above-described surfactant or coupling agent.

  In the case of forming a vertical alignment film with the above-described surfactant or coupling agent, this vertical alignment film is obtained by dissolving a coating liquid obtained by dissolving a desired surfactant or coupling agent in an organic solvent such as isopropyl alcohol. It is obtained by using to form a coating film and curing the coating film. At this time, the thickness of the vertical alignment film can be appropriately selected within a range of about 10 to 1000 nm.

  In the case where the birefringent layer 15 in which the polymerizable liquid crystal is homeotropically aligned is formed, the underlying layer may be a silicon oxide film. FIG. 3B is a schematic diagram illustrating an example of a basic cross-sectional structure of the color filter substrate 50 using the base material 10 </ b> B having the silicon oxide film 7. The color filter substrate 50 is formed on one side of the light-transmitting substrate 1 (however, in addition to the plate-like material, it may be a sheet-like material or a film-like material). The substrate 10B is constituted by the silicon oxide film 7, and the birefringent layer 15 is formed on the silicon oxide film 7, which is different from the color filter substrate 30 shown in FIG. Since the other configuration of the color filter substrate 50 is the same as the configuration of the color filter substrate 30, among the components shown in FIG. 3B, those common to the components shown in FIG. The same reference numerals as those used are assigned, and the description thereof is omitted. The silicon oxide film 7 can be formed by, for example, physical vapor deposition (PVD) or chemical vapor deposition (CVD).

  Regardless of whether or not the orientation order of the polymerizable liquid crystal in the birefringent layer 15 is improved, and regardless of the means by which the orientation order of the polymerizable liquid crystal is improved, it is relatively heat resistant. From the viewpoint of obtaining a high birefringent layer 15, the degree of crosslinking is preferably about 80% or more, more preferably about 90% or more.

<Color filter substrate (second form)>
FIG. 4 is a schematic view showing another example of the basic cross-sectional structure of the color filter substrate of the present invention. The color filter substrate 70 shown in the figure has a structure in which a transparent electrode 60 is formed on the color filter layer 25 in the color filter substrate 30 shown in FIG. Since the configuration of the color filter substrate 70 excluding the transparent electrode 60 is the same as the configuration of the color filter substrate 30, the components already shown in FIG. 1 among the components shown in FIG. 4 are used in FIG. The same reference numerals as in the reference numerals are attached, and the description thereof is omitted.

  When the transparent electrode 60 is used to produce a liquid crystal display substrate using the color filter substrate 70 and further to produce a display liquid crystal panel using the liquid crystal display substrate, all of the transparent liquid crystal panels in the display liquid crystal panel are used. It is used as an electrode (common electrode) common to the pixels. This transparent electrode 60 is obtained by forming a film of an inorganic transparent electrode material such as ITO into a desired shape by PVD or CVD.

  In the color filter substrate 70, the interface reflection is reduced for the same reason as the color filter substrate 30 shown in FIG. Moreover, the temperature range which can maintain a desired birefringence characteristic is comparatively wide. Furthermore, cracks in the transparent electrode 60 due to the difference in thermal shrinkage between the inorganic transparent electrode material and the birefringent layer 15 after the film formation of the transparent electrode 60 are suppressed.

  Therefore, by using the color filter substrate 70 as a material for a liquid crystal display substrate and further using the liquid crystal display substrate as a material for a display liquid crystal panel, the display characteristics are relatively high and desired display characteristics are obtained. It is easy to obtain a liquid crystal display device having a relatively wide temperature range in which the above can be maintained.

  The color filter substrate having the same technical effect as the above-described color filter substrate 70 can be obtained by, for example, forming a transparent electrode on the color filter layer 25 in the color filter substrate 40 shown in FIG. Alternatively, it can also be obtained by forming a transparent electrode on the color filter layer 25 in the color filter substrate 50 shown in FIG.

<Liquid crystal substrate>
FIG. 5 is a schematic view showing an example of a basic cross-sectional structure of the liquid crystal display substrate of the present invention. The liquid crystal display substrate 90 shown in the figure has a structure in which an alignment film 80 is provided on the transparent electrode 60 in the color filter substrate 70 of the second embodiment shown in FIG. Among the 90 constituent members, those already shown in FIG. 4 are given the same reference numerals as those used in FIG. 4 and their description is omitted.

  The alignment film 80 is a horizontal alignment film capable of horizontally aligning the liquid crystal in the liquid crystal cell when the liquid crystal display substrate 90 is produced using the liquid crystal display substrate 90, or the liquid crystal is vertically aligned. This is a vertical alignment film that can be used. Which of the horizontal alignment film and the vertical alignment film is used as the alignment film 80 can be appropriately selected according to the operation mode of the display liquid crystal panel to be manufactured using the liquid crystal display substrate 90.

  Since the liquid crystal display substrate 90 of this embodiment is manufactured using the color filter substrate 70 shown in FIG. 4, for the reason already described in the description of the color filter substrate 70, the interface reflection is performed. Is reduced. Moreover, the temperature range which can maintain a desired birefringence characteristic is comparatively wide. Furthermore, cracks in the transparent electrode 60 due to the difference in thermal shrinkage between the inorganic transparent electrode material and the birefringent layer 15 after the film formation of the transparent electrode 60 are suppressed.

  Therefore, by using the liquid crystal display substrate 90 as a material for a display liquid crystal panel, a liquid crystal display device having a relatively high display characteristic and a wide temperature range capable of maintaining a desired display characteristic is obtained. Easy to get.

  The liquid crystal display substrate having the same technical effect as the liquid crystal display substrate 90 described above has a transparent electrode and an alignment film on the color filter layer 25 in the color filter substrate 40 shown in FIG. It can also be obtained by laminating in this order or by laminating a transparent electrode and an alignment film in this order on the color filter layer 25 in the color filter substrate 50 shown in FIG.

<Liquid crystal display device (first form)>
FIG. 6 is a partial sectional view schematically showing an example of the liquid crystal display device of the present invention. The illustrated liquid crystal display device 300 includes a display liquid crystal panel 200, a backlight unit 250 installed behind the display liquid crystal panel 200, and an active matrix drive transmission type that includes an external circuit (not shown). It is a liquid crystal display device.

  The display liquid crystal panel 200 includes the liquid crystal display base material 90 shown in FIG. 5 as a display surface side substrate (first liquid crystal display base material), and a back side substrate (second liquid crystal display base material). ) As a liquid crystal display substrate 150.

  The liquid crystal display substrate 150 includes a transparent electrode 115, a signal line 120, a protection line, a scanning line, an interlayer insulating film 110, and a large number of pixel electrodes 115 a arranged in a matrix on a light-transmitting substrate 105. It has a structure in which a film (passivation film) 125, a switching circuit portion, and an alignment film 130 are provided.

  Although the scanning lines do not appear in FIG. 6, the scanning lines are arranged so as to correspond to one row of a large number of pixel electrodes 115a arranged in a matrix and extend in the longitudinal direction of the row. . Each scanning line can be formed of a metal such as tantalum (Ta) or titanium (Ti). These scanning lines are covered with an interlayer insulating film 110.

  The interlayer insulating film 110 is formed of an electrically insulating material such as silicon oxide, for example, and electrically separates the scanning lines and the signal lines 120 and electrically separates the pixel electrodes 115a and the scanning lines. ing.

  Each pixel electrode 115a is formed of an inorganic transparent electrode material such as indium tin oxide (ITO), for example, so as to correspond to each pixel in the display liquid crystal panel 200. The shape of each pixel electrode 115a in plan view can be, for example, a polygon such as a quadrangle or a hexagon formed by cutting one corner of the quadrangle into a rectangle.

  The signal lines 120 are arranged so as to correspond to one column of a large number of pixel electrodes 115a arranged in a matrix, and extend in the longitudinal direction of the column. Each signal line 120 can be formed of a metal such as tantalum (Ta) or titanium (Ti). These signal lines 120 are covered with a protective film 125.

  The protective film 125 is formed of, for example, silicon nitride and protects the underlying member. Further, the signal line 120 and the pixel electrode 115a are electrically separated.

  Although the switching circuit portion does not appear in FIG. 6, the switching circuit portion is arranged corresponding to one pixel electrode 115 a one by one, and the pixel electrode 115 a corresponding to the switching circuit portion is connected to the scanning line and the signal line 120. Electrically connected. Each switching circuit unit receives a signal from a corresponding scanning line and controls conduction between the signal line 120 and the pixel electrode 115a. Each switching circuit unit can be configured using, for example, one active element. As the active element, for example, a three-terminal element such as a thin film transistor or a two-terminal element such as an MIM (Metal Insulator Metal) diode is used.

  The alignment film 130 is a horizontal alignment film that can horizontally align the liquid crystal in the display liquid crystal panel 200 or a vertical alignment film that can vertically align the liquid crystal.

  Which one of the horizontal alignment film and the vertical alignment film is used as the alignment film 80 in the liquid crystal display substrate 90 and the alignment film 130 in the liquid crystal display substrate 150 depends on the operation mode of the liquid crystal display device 300 or the like. Selected.

  The liquid crystal display substrate 90 and the liquid crystal alignment substrate 150 are spaced apart so that the alignment film 80 in the liquid crystal display substrate 90 and the alignment film 130 in the liquid crystal display substrate 150 face each other. A sealing material (thermosetting resin) 160 is attached. The distance (cell gap) between the liquid crystal display substrates 90 and 150 is kept constant by a spacer (not shown) (for example, a spherical spacer or a columnar spacer), and the gap between the two is filled with a liquid crystal material. Thus, the liquid crystal layer 170 is formed. An analyzer 172 is attached to the outer surface of the liquid crystal display substrate 90, and a polarizer 174 is attached to the outer surface of the liquid crystal display substrate 150. The analyzer 172 and the polarizer 174 can be arranged so as to have a crossed Nicols relationship or can be arranged so as to have a parallel Nicols relationship. The backlight unit 250 is disposed behind the liquid crystal display substrate 150.

  In the liquid crystal display device 300 having such a configuration, the liquid crystal display substrate 90 described above is used as the first liquid crystal alignment substrate in the display liquid crystal panel 200. For the reasons described above, it is easy to make display characteristics relatively high, and it is also easy to obtain a relatively wide temperature range in which desired display characteristics can be maintained.

<Liquid crystal display device (second embodiment)>
FIG. 7 is a cross-sectional view schematically showing another example of the liquid crystal display device of the present invention. The illustrated liquid crystal display device 600 is an active matrix drive type reflective liquid crystal display device including a display liquid crystal panel 500 and an external circuit (not shown).

  The display liquid crystal panel 500 includes the liquid crystal display base material 90 shown in FIG. 5 as a display surface side substrate (first liquid crystal display base material), and a back side substrate (second liquid crystal display base material). ) As a liquid crystal display substrate 450.

  The liquid crystal display substrate 450 includes a scanning line, a first interlayer insulating film 410, a signal line 415, a second interlayer insulating film 420, and a large number of pixel electrodes 425a arranged in a matrix on a substrate 405. The electrode pattern 425, the switching circuit portion, and the alignment film 430 are provided.

  Although not shown in FIG. 7, the scanning lines are arranged so as to correspond to one of the pixel rows in the display liquid crystal panel 500 and extend in the longitudinal direction of the corresponding pixel row. Each scanning line can be formed of a metal such as tantalum (Ta) or titanium (Ti). These scanning lines are covered with a first interlayer insulating film 410.

  The first interlayer insulating film 410 is formed of an electrically insulating material such as silicon oxide, for example, and electrically separates the scanning lines and the signal lines 415.

  The signal lines 415 are arranged so as to correspond to one of the pixel columns in the display liquid crystal panel 500, and extend in the longitudinal direction of the corresponding pixel column. Each signal line 415 can be formed of a metal such as tantalum (Ta) or titanium (Ti). These signal lines 415 are covered with a second interlayer insulating film 420.

  The second interlayer insulating film 420 is formed of, for example, silicon nitride, and electrically isolates the signal line 415 and the pixel electrode 425a.

  Each pixel electrode 425a is an electrode that also serves as a reflector, and is formed of, for example, aluminum or the like so as to correspond to one pixel in the display liquid crystal panel 500 one by one. The shape of each pixel electrode 425a in plan view can be, for example, a polygon, such as a quadrangle or a hexagon formed by cutting one corner of the quadrangle into a rectangle.

  Although the switching circuit portion does not appear in FIG. 7, the switching circuit portion is arranged corresponding to one pixel electrode 425a one by one, and the pixel electrode 425a corresponding to the switching circuit portion is connected to the scanning line and the signal line 415. Electrically connected. Each switching circuit unit receives a signal from a corresponding scanning line and controls conduction between the signal line 415 and the pixel electrode 425a. Each switching circuit unit can be configured using, for example, one active element. As the active element, for example, a three-terminal element such as a thin film transistor or a two-terminal element such as an MIM (Metal Insulator Metal) diode is used.

  The alignment film 430 is a horizontal alignment film that can horizontally align the liquid crystal in the display liquid crystal panel 500 or a vertical alignment film that can vertically align the liquid crystal.

  Whether the horizontal alignment film or the vertical alignment film is used as the alignment film 80 in the liquid crystal display substrate 90 and the alignment film 430 in the liquid crystal display substrate 450, respectively, depends on the operation mode of the liquid crystal display device 600 and the like. Selected.

  The liquid crystal display substrate 90 and the liquid crystal display substrate 450 are spaced apart such that the alignment film 80 in the liquid crystal display substrate 90 and the alignment film 430 in the liquid crystal display substrate 450 face each other. In the state, it is bonded by a sealing material (thermosetting resin) 460. The interval (cell gap) between the liquid crystal display substrates 90 and 450 is kept constant by a spacer (not shown) (for example, a spherical spacer or a columnar spacer), and the gap between the two is filled with a liquid crystal material. Thus, a liquid crystal layer 470 is formed. An analyzer 472 is attached to the outer surface of the liquid crystal display substrate 90.

  In the liquid crystal display device 600 having such a configuration, the liquid crystal display substrate 90 described above is used as the first liquid crystal alignment substrate in the display liquid crystal panel 500. For the reasons described above, it is easy to make display characteristics relatively high, and it is also easy to obtain a relatively wide temperature range in which desired display characteristics can be maintained.

  In the liquid crystal display device of the present invention, one of the two liquid crystal display substrates constituting the display liquid crystal panel may be the liquid crystal display substrate of the present invention, and the other liquid crystal display substrate. These configurations can be appropriately changed according to the operation method, drive method, application, grade, etc. of the liquid crystal display device, and various modifications, improvements, combinations, and the like are possible.

<Example 1; Production of color filter substrate>
First, a 0.7 mm-thick alkali-free glass substrate (NA35 manufactured by NH Techno Glass) is prepared, and a polyimide material (AL1254; trade name) manufactured by JSR is applied to one side by flexographic printing. A film was formed. Subsequently, the surface of this coating film was rubbed to form a horizontal alignment film. Thereby, the base material which has an alkali free glass substrate and the horizontal alignment film formed in the single side | surface was obtained.

  Separately, 75 parts by weight of a polyfunctional polymerizable liquid crystal and 1 part by weight of a photopolymerization initiator were dissolved in 24 parts by weight of toluene to prepare a coating composition for forming a birefringent layer. At this time, what is represented by the formula (IV) shown in FIG. 2D is used as the polyfunctional polymerizable liquid crystal, and Irgacure 184 (Irg184) manufactured by Ciba Specialty Chemicals is used as the photopolymerization initiator. Was used.

  Next, the above coating composition is spin-coated on the above-mentioned horizontal alignment film to form a coating film, and the solvent is removed by drying under reduced pressure to form a polymerizable liquid crystal layer. For 5 minutes at 100 ° C. The polymerizable liquid crystal layer changed from a cloudy state to a transparent state as it was heated. From this, it was confirmed that the polymerizable liquid crystal in the polymerizable liquid crystal layer had undergone a phase transition from the crystal phase to the liquid crystal phase by heating.

While the polymerizable liquid crystal layer in which the polymerizable liquid crystal has undergone phase transition is heated to 100 ° C., the dry coating film is irradiated with ultraviolet rays having a wavelength of 365 nm in an air atmosphere to three-dimensionally crosslink the polymerizable liquid crystal in the polymerizable liquid crystal layer. I let you. The ultraviolet irradiation at this time was performed under the conditions of an irradiation intensity of 10 mW / cm ² and an irradiation time of 3 minutes. In this way, a birefringent layer having a thickness of 3.0 μm was obtained by three-dimensionally crosslinking the polymerizable liquid crystal in the polymerizable liquid crystal layer.

  When the birefringence characteristic of this birefringent layer was measured using KOBRA-21 manufactured by Oji Scientific Instruments under the condition of a measurement wavelength of 589.3 nm, a uniaxial birefringent layer having an in-plane optical axis ( The so-called “+ A plate”) was confirmed. From this, it is determined that the polymerizable liquid crystal is homogeneously aligned in the birefringent layer. Further, if the polymerizable liquid crystal is uncrosslinked, even if the birefringent layer is heated to 180 ° C., which is a temperature at which the polymerizable liquid crystal exhibits an isotropic phase, the retardation amount of the birefringent layer is increased. There was no change. From this, in the birefringent layer, it is determined that the polymerizable liquid crystal molecules are three-dimensionally crosslinked.

  Next, a color resin layer containing a black pigment was formed on the birefringent layer, and this layer was patterned by a photolithography method to obtain a light-shielding layer (black matrix). Also, a color resin layer containing a red pigment was formed on the birefringent layer, and this layer was patterned by a photolithography method to form a red color filter at a predetermined location. Hereinafter, in the same manner as the formation of the red color filter, a green color filter and a blue color filter are provided at predetermined positions on the birefringent layer using a color resin containing a green pigment or a color resin containing a blue pigment. Were sequentially formed. By forming these color filters at predetermined positions on the birefringent layer, a primary color filter layer was formed on the birefringent layer.

  Thereafter, an ITO film having a film thickness of 200 nm was formed by a sputtering method so as to cover the color filter layer and at a film formation temperature of 200 ° C. under reduced pressure. At this time, it is also possible to form an ITO film only in a necessary region using a metal mask or the like. The ITO film corresponds to a transparent electrode.

  In the color filter substrate thus obtained, since the color filter layer functions as a protective layer (buffer layer), the generation of cracks in the ITO film after the formation of the ITO film was suppressed. As a result, white turbidity did not occur in the ITO film.

Example 2 Production of Color Filter Substrate
In preparing a coating composition for forming a birefringent layer, 5 parts by weight of a polymerizable chiral agent represented by the following formula (I) (wherein n represents an integer of 4 to 8) is further used. A color filter substrate was produced under the same conditions as in Example 1 except that the amount of toluene used was changed from 24 parts by weight to 19 parts by weight. The birefringent layer has a thickness of 2.4 μm.

  When the birefringence characteristics of the birefringent layer were measured in the same manner as in Example 1 except that the observation polar angle was appropriately changed during measurement in the process of manufacturing the color filter substrate, the birefringent layer was measured in the thickness direction. It was confirmed that the optical axis was uniaxial (so-called “-C plate”) having a refractive index in the thickness direction smaller than the in-plane refractive index. From this, in the birefringent layer, it is judged that the polymerizable liquid crystal is cholesterically aligned to form a planar structure. Further, even when the birefringent layer was heated to 180 ° C., the amount of retardation of the birefringent layer was not changed. From this, in the birefringent layer, it is determined that the polymerizable liquid crystal molecules are three-dimensionally crosslinked.

  When this color filter substrate was observed with the naked eye, similar to the color filter substrate produced in Example 1, at least in a region overlapping with the color filter layer in plan view, a cloudy portion was not recognized.

Example 3 Production of Color Filter Substrate
First, TSL8233 and TSL8114 (both trade names) made by Toshiba Silicone were mixed at a ratio of 10: 3 (mass ratio), and this mixture was hydrolyzed to obtain a silane coupling agent. .

  Next, 25 parts by weight of a polyfunctional polymerizable liquid crystal and 1 part by weight of a photopolymerization initiator are dissolved in 74 parts by weight of 3-methoxybutyl acetate to obtain a polymerizable liquid crystal solution. This polymerizable liquid crystal solution and the above silane cup A solution obtained by diluting a ring agent with isopropyl alcohol to 10 wt% was mixed at a ratio of 99.25: 0.75 (mass ratio) to prepare a coating composition for forming a birefringent layer. As the polyfunctional polymerizable liquid crystal, the one represented by the formula (IV) shown in FIG. 2D is used, and Irgacure 184 (Irg184) manufactured by Ciba Specialty Chemicals is used as the photopolymerization initiator. It was.

  A color filter substrate was produced under the same conditions as in Example 1 except that the above-described coating composition was used in forming the birefringent layer. The film thickness of the birefringent layer in this color filter substrate is 1.9 μm.

  In the process of manufacturing the color filter substrate, the birefringence characteristics of the birefringent layer were measured in the same manner as in Example 2. As a result, the birefringent layer had an optical axis in the thickness direction, and the refractive index in the thickness direction. Is uniaxial with a refractive index larger than the in-plane refractive index (so-called “+ C plate”). From this, it is determined that the polymerizable liquid crystal is homeotropically aligned in the birefringent layer. If the polymerizable liquid crystal is uncrosslinked, even if the birefringent layer is heated to 180 ° C., which is the temperature at which the polymerizable liquid crystal exhibits an isotropic phase, the retardation of the birefringent layer is reduced. There was no change. From this, in the birefringent layer, it is determined that the polymerizable liquid crystal molecules are three-dimensionally crosslinked.

  When this color filter substrate was observed with the naked eye, similar to the color filter substrate produced in Example 1, at least in a region overlapping with the color filter layer in plan view, a cloudy portion was not recognized.

It is the schematic which shows an example of the basic cross-section of the color filter substrate of this invention. 2 (a) to 2 (e) are formulas each representing a polyfunctional polymerizable liquid crystal having a rod-like molecular shape, and FIGS. 2 (f) to 2 (i) are respectively rod-like molecular shapes. This is a formula representing a monofunctional polymerizable liquid crystal. FIG. 3A is a schematic view showing an example of a basic cross-sectional structure of the color filter substrate of the present invention using a base material having an alignment film, and FIG. 3B has a silicon oxide film. It is the schematic which shows an example of the basic cross-section of the color filter substrate of this invention using a base material. It is the schematic which shows the other example of the basic cross-section of the color filter substrate of this invention. It is the schematic which shows an example of the basic cross-section of the base material for liquid crystal displays of this invention. It is a fragmentary sectional view which shows an example of the liquid crystal display device of this invention roughly. It is sectional drawing which shows schematically the other example of the liquid crystal display device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10A, 10B Light-transmitting substrate 15 Birefringent layer 25 Color filter layer 30, 40, 50, 70 Color filter substrate 60 Transparent electrode 80 Alignment film 90 Liquid crystal display substrate (first liquid crystal display substrate Material)
150, 450 Second liquid crystal display substrate 300, 600 Liquid crystal display device

Claims (4)

  A substrate having light permeability, a birefringent layer formed on the substrate by a three-dimensionally crosslinked polymerizable liquid crystal, and a color filter layer formed on the birefringent layer. Color filter substrate.   The color filter substrate according to claim 1, wherein a transparent electrode is formed on the color filter layer.   A substrate for a liquid crystal display comprising the color filter substrate according to claim 2 and an alignment film covering the transparent electrode. A liquid crystal display device comprising a display liquid crystal panel having a first liquid crystal display substrate positioned on the display surface side and a second liquid crystal display substrate positioned on the back side,
4. The liquid crystal display device according to claim 3, wherein one of the first liquid crystal display substrate and the second liquid crystal display substrate is the liquid crystal display substrate according to claim 3.

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