JP2007071952A - Optical anisotropic body, its manufacturing method, and optical element and display element using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical anisotropic body for contributing improvement of view angle characteristics when being used to be incorporated in a color image display, in particular, a color liquid crystal display having pixels comprising display regions of three colors of red color, green color and blue color. <P>SOLUTION: The optical anisotropic body used to be incorporated in the display element having the pixels comprising the display regions of the three colors of the red color, the green color and the blue color, is patterned in a unit corresponding to each sub-pixel equivalent to the red color, the green color and the blue color. Each patterned unit is composed of a plurality of division regions. Each division region includes discotic liquid crystal molecules. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optically anisotropic body used by being incorporated in a display element such as a liquid crystal display element, a method for producing the same, and a display element using the same.

  Optical films with an optically anisotropic layer in which liquid crystal compounds are highly oriented and fixed have been developed in various applications such as optical compensation films for liquid crystal display devices, brightness enhancement films, and optical compensation films for projection display devices. In particular, the development as an optical compensation film of a liquid crystal display device is remarkable. Usually, the liquid crystal display device includes a polarizing plate and a liquid crystal cell. In the TN type TFT liquid crystal display device which is currently mainstream, an optical compensation film is inserted between the polarizing plate and the liquid crystal cell to realize a liquid crystal display device with high display quality. Further, an invention has been proposed in which the front contrast can be increased without increasing the thickness of the liquid crystal display device by using an elliptically polarizing plate having a retardation film on one side of the polarizing film and a protective film on the other side. (For example, refer to Patent Document 1). However, the retardation film (optical compensation film) having the above-described structure has a problem that a sufficient viewing angle improvement effect cannot be obtained and the display quality of the liquid crystal display device is deteriorated.

  Currently, an optical compensation film in which an optically anisotropic layer formed from a discotic liquid crystal compound is coated on a transparent support is directly used as a protective film for a polarizing plate, thereby thickening the liquid crystal display device. Without the problem, the problem concerning the viewing angle is greatly improved (see, for example, Patent Documents 2 and 3).

  On the other hand, a method of using an optical anisotropy patterned in units corresponding to sub-pixels corresponding to red, green and blue for an optical compensation film has been studied, and a liquid crystal layer made of a rod-like liquid crystal compound is optically anisotropic. In the example used as a sex body, the viewing angle and display characteristics of the liquid crystal display device are improved (for example, Patent Documents 4 and 5).

However, even in such an optical compensation film, the viewing angle characteristics are still not sufficient. Further improvements were sought.
JP-A-2-247602 Japanese Patent Laid-Open No. 7-191217 European Patent No. 0911656A2 JP-A-6-194521 JP 2004-191832 A

  The present invention is an optical anisotropy that contributes to an improvement in viewing angle characteristics when used in a color image display device, particularly a color liquid crystal display device, having pixels composed of display areas of three colors of red, green, and blue. It is an object to provide a body, a display element including the body, and a method for manufacturing an optically anisotropic body.

The object of the present invention has been achieved by the following (1) to (8).
(1) An optically anisotropic body that is used by being incorporated in a display element having a pixel composed of display areas of three colors of red, green, and blue,
It is patterned into units corresponding to each of the sub-pixels corresponding to red, green and blue, and each patterned unit is composed of a plurality of divided regions, and each divided region has a discotic liquid crystal molecule. An optical anisotropy containing.
(2) The optically anisotropic body according to (1), wherein discotic liquid crystal molecules are fixed in a nematic hybrid alignment state in the divided region.
(3) A curve formed in a thickness direction by molecules fixed in a nematic hybrid alignment state of at least one of the divided regions, and a nematic hybrid alignment state of the other one region of the divided regions. (2) Optical anisotropy different from the curve formed by the fixed molecules in the thickness direction.
(4) The curve formed in the thickness direction by the molecule fixed in the nematic hybrid orientation state of at least one of the divided regions is a counterclockwise curve, and the other one of the divided regions The optically anisotropic body of (2) or (3), wherein the curve formed in the thickness direction by the molecules fixed in the nematic hybrid alignment state is a clockwise curve.
(5) The optically anisotropic body according to any one of (2) to (4), wherein nematic hybrid orientations of at least two adjacent divided regions are substantially mirror-symmetric with each other.
(6) The optical anisotropic body according to any one of (1) to (5), wherein the plurality of divided regions are 2 to 8 regions.
(7) The optically anisotropic body according to any one of (1) to (6), wherein the length of each side of the divided region is 0.1 μm to 200 μm.
(8) The optical anisotropy according to any one of (1) to (7), wherein each of the divided regions is a region formed from a composition containing a discotic liquid crystalline compound having a polymerizable group or a crosslinkable group. body.
(9) An optical element having a substrate and any one of the optical anisotropic bodies (1) to (8) disposed on the substrate.
(10) An optical element having a substrate having a fine pattern of each color of red, green, and blue, and the optical anisotropic body of any one of (1) to (8) disposed on the substrate.
(11) A display element including the optically anisotropic material according to any one of (1) to (8) or the optical element according to (9) or (10).

(12) A method for producing an optical anisotropic body used by being incorporated in a display element having a pixel composed of display areas of three colors of red, green and blue,
1) a step of forming a photo-alignment film on a substrate or a color filter;
2) A step of irradiating the photo-alignment film with light to form a pattern corresponding to each sub-pixel corresponding to red, green and blue, and dividing each pattern into a plurality of divided regions;
3) Applying a composition containing a discotic liquid crystalline compound to the surface of the photo-alignment film that has been irradiated with light and divided into a plurality of divided regions, aligns the molecules of the discotic liquid crystalline compound, and A step of forming a liquid crystal layer on each surface of the divided region of the alignment film, and 4) a step of curing the liquid crystal layer by a polymerization reaction,
The manufacturing method of the optically anisotropic body containing this.
(13) In the step 2) of irradiating the photo-alignment film with light, a laser beam obtained by combining a plurality of laser beams respectively emitted from a plurality of semiconductor lasers is irradiated with light through a multimode optical fiber. (12) The method for producing an optically anisotropic material.

  The optically anisotropic body of the present invention contributes to the improvement of viewing angle characteristics by being incorporated in a color image display device having pixels composed of display areas of three colors of red, green and blue, particularly a color liquid crystal display device. The color image display device having the optically anisotropic material of the present invention exhibits excellent viewing angle characteristics.

BEST MODE FOR CARRYING OUT THE INVENTION

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

In this specification, Re represents in-plane retardation at the wavelength λ. Re is measured in KOBRA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) by making light of wavelength λ nm incident on the substrate in the normal direction. Re (40) and Re (−40) are wavelengths λ nm from a direction inclined by +40 degrees with respect to the normal direction of the substrate with an in-plane slow axis (determined by KOBRA 21ADH) as an inclination axis (rotation axis). The retardation value measured by making this light incident and the retardation value measured by making light having a wavelength λ nm incident from a direction inclined by −40 degrees with respect to the normal direction of the substrate are shown.
In the present specification, λ refers to 611 ± 5 nm, 545 ± 5 nm, 435 ± 5 nm for R, G, and B, respectively, and refers to 545 ± 5 nm or 590 ± 5 nm unless otherwise specified.

  In this specification, “substantially” for the angle means that the error from the exact angle is within a range of less than ± 5 degrees. Furthermore, the error from the exact angle is preferably less than 4 degrees, and more preferably less than 3 degrees. With regard to retardation, “substantially” means that the retardation is within ± 5%. In addition, the measurement wavelength of the refractive index indicates an arbitrary wavelength in the visible light region unless otherwise specified. In the present specification, “visible light” refers to light having a wavelength of 400 to 700 nm.

Embodiments of the present invention will be described below with reference to the drawings.
First, an optically anisotropic body according to an embodiment of the present invention will be described.
(Optical anisotropy)
As shown in FIG. 1, the optical anisotropic body 11 according to the present embodiment includes units 14 and 15 corresponding to sub-pixels corresponding to red (R), green (G), and blue (B). Each of the patterned units 14, 15 and 16 is configured by a plurality of divided regions 14a and 14b, 15a and 15b, and 16a and 16b. Further, each of the divided regions 14a, 14b, 15a, 15b, 16a, and 16b includes discotic liquid crystal molecules. The discotic liquid crystal molecules are preferably fixed in a predetermined alignment state, for example, a nematic hybrid alignment state, in each region.

  Although FIG. 1 shows a mode in which each unit is divided into two divided regions, in the present invention, any unit in which each unit includes two or more divided regions may be used. In general, it is preferably divided into 2 to 8 divided regions, and more preferably divided into 2 to 4 divided regions. The divided areas are preferably similar in shape to pixels, and are generally preferably rectangular parallelepipeds or cubes. In the case of such a shape, generally, the length of each side is preferably 0.1 to 200 μm. Of each side, the horizontal or vertical length is preferably 1 to 200 μm, and more preferably 1 to 100 μm. In addition, the height (thickness) of each side is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and further preferably 1 to 10 μm. In addition, when the shape is not a cube or a rectangular parallelepiped, for example, a columnar shape or an elliptical column shape, the minor axis and the major axis of the cross section are preferably 1 to 200 μm, and the height is 0.1 to 20 μm. preferable.

  The optical anisotropic body 11 of the present embodiment is formed on the substrate 12. An alignment layer 13 may be provided between the optical anisotropic body 11 and the substrate 12 as necessary. Further, the substrate may be a color filter, that is, a substrate having a fine pattern of each color of red, green, and blue.

The optically anisotropic body of the present invention is composed of a plurality of divided regions containing discotic liquid crystalline molecules, and in each divided region, the discotic liquid crystalline molecules are preferably fixed in a nematic alignment state. Furthermore, a curve formed in the depth direction by molecules fixed in a nematic hybrid orientation state of at least one of the divided regions (for example, 14a in FIG. 1), and another one of the divided regions It is preferable that the curves formed in the depth direction by molecules fixed in the nematic hybrid alignment state (for example, 14b in FIG. 1) are different from each other.
Here, the “curve formed by molecules fixed in the nematic hybrid alignment state in the depth direction” will be described. As shown in FIG. 2, in the nematic hybrid alignment, the discotic liquid crystal molecules are aligned with a predetermined inclination angle with respect to the layer plane of the discotic liquid crystal molecules, and the inclination angle is one interface (for example, an alignment film). It increases (or decreases) from the interface) toward the other interface (for example, the air interface), that is, in the thickness direction of the layer. A line connecting the center points of the disc surfaces of the discotic liquid crystal molecules in the thickness direction forms a curve as shown in FIG. In this specification, this curve is referred to as “a curve formed by molecules fixed in a nematic hybrid orientation state in the depth direction”.

  The curves formed by the discotic liquid crystalline molecules in the divided regions being different from each other means that the directions of the curves are different. For example, as shown in FIG. 2, a curve formed in the depth direction by molecules fixed in the nematic hybrid orientation state of at least one of the divided regions (for example, 14a, 15a, and 16a in FIG. 1) In the case of a counterclockwise curve, a curve formed in the depth direction by a molecule fixed in the nematic hybrid orientation state of the other one of the divided regions (for example, 14b, 15b, and 16b in FIG. 1) As shown in FIG. 3, it is preferably clockwise. Nematic hybrid orientations in adjacent divided regions are preferably substantially mirror-symmetric with each other, i.e., one forms a clockwise curve and the other forms a counterclockwise curve. .

  The curve formed by the discotic molecules in each divided region is preferably averaged over the entire divided region included in one unit corresponding to the subpixel. For example, as shown in FIG. 1, when two divided regions are included in one unit, as described above, molecules in one divided region form a counterclockwise curve, and molecules in other divided regions are formed. Preferably forms a clockwise curve, is mirror-symmetric and is averaged. Similarly, when the divided areas are arranged in 2 columns × 2 rows (4 pieces), 2 columns × 3 rows (6 pieces), 2 columns × 4 rows (8 pieces), etc., one column is clockwise. A curved divided area may be arranged, and a counterclockwise curved divided area may be arranged for the other columns. When the divided area is 2 × 2, the curve direction may be shifted by 90 ° and averaged for each of the four divided areas. In this way, it is preferable to adjust and average the nematic hybrid orientation curve in each divided region according to the number and arrangement of the divided regions included in one unit.

  In the present invention, the divided region forming the optically anisotropic body is preferably formed from a composition containing a discotic liquid crystalline compound having a polymerizable group or a crosslinkable group. The composition is irradiated with heat, light or the like to cause a discotic liquid crystal molecule to undergo a polymerization reaction or a cross-linking reaction. The divided region may be formed from a crosslinked body. In the divided region, the discotic liquid crystalline molecules are preferably fixed in an aligned state, and most preferably fixed in an aligned state by polymerization or a crosslinking reaction. The polymerization of discotic liquid crystalline compounds is described in JP-A-8-27284.

The optically anisotropic body of the present invention can be easily produced by a method including the following steps using a photo-alignment film.
1) forming a photo-alignment film on the surface of a substrate or the like;
2) A step of irradiating the photo-alignment film with light to form a pattern in units corresponding to each of the sub-pixels corresponding to red, green and blue, and dividing each pattern into a plurality of divided regions;
3) Applying a composition containing a discotic liquid crystalline compound to the surface of the photo-alignment film that has been irradiated with light and divided into a plurality of divided regions, aligns the molecules of the discotic liquid crystalline compound, and A step of forming a liquid crystal layer on the surface of each of the divided regions of the alignment film; and 4) a step of curing the liquid crystal layer by a polymerization reaction.

  The substrate used in the step 1) is preferably a transparent substrate. Examples of the transparent substrate include a glass substrate and a polymer substrate having a light transmittance of 80% or more as particularly preferable examples. In the present invention, the polymer substrate includes a polymer film. Examples of polymer substrates include cellulose esters (eg, cellulose acetate, cellulose propionate, cellulose butyrate), polyolefins (eg, norbornene polymers), poly (meth) acrylic acid esters (eg, polymethyl methacrylate), Polycarbonate, polyester and polysulfone are included. Commercially available polymers (for norbornene polymers, Arton (manufactured by JSR), ZEONOR (manufactured by Nippon Zeon), etc.) may be used.

  The substrate may be colored, and may be a substrate such as a color filter having a fine pattern of each color of red, green, and blue separated by a black matrix or the like, and the optical filter of the present invention may be formed on the surface of the color filter. An anisotropic body may be formed.

  In the step 1), a photo-alignment film is formed on the surface of a substrate or the like. The “photo-alignment film” refers to a film that develops an alignment function by light irradiation. The material used for forming the photo-alignment film is preferably a compound having a photo-alignment group that develops a photo-alignment function. For example, a compound having a photo-alignment group that photoisomerizes such as an azo group, a cinnamoyl group, a coumarin group A compound having a photo-alignment group capable of photodimerization such as a chalcone group is preferable. Also, preferred examples include a compound that exhibits an alignment function by photocrosslinking such as a benzophenone group, and a compound that exhibits an alignment function by photodecomposition such as a polyimide resin.

The photo-alignment film can be formed by applying a material for a photo-alignment film, for example, a composition containing a compound having a photo-alignment group on a substrate or a color filter. It is preferable to prepare the composition as a coating solution, and apply and dry it on the surface of a substrate or the like. Specifically, the compound having the photo-alignment group or the like is dissolved or dispersed in an appropriate solvent to prepare a coating solution, and the coating solution is applied to a substrate or a color filter surface and dried to form. It is preferable to do this. The coating solution can be carried out by a known method (eg, spin coating method, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).
The thickness of the photo-alignment film is preferably 0.01 to 2 μm, more preferably 0.01 to 0.1 μm.

  In the step 2), the photo-alignment film is irradiated with light (patterning process of the photo-alignment film). By light irradiation, the photo-alignment film is patterned into units corresponding to the sub-pixels corresponding to red, green, and blue, and each pattern is divided into a plurality of divided regions. For light irradiation for pattern formation, a method using a mask or a method using direct drawing by a laser can be employed. In the light irradiation, the wavelength of light used varies depending on the photo-alignment film used and is not particularly limited. Preferably, the peak wavelength of light used for light irradiation is 200 nm to 700 nm, and more preferably the peak wavelength of light is 300 nm to 700 nm.

  The light source used for light irradiation is a commonly used light source such as a tungsten lamp, a halogen lamp, a xenon lamp, a xenon flash lamp, a mercury lamp, a mercury xenon lamp, a carbon arc lamp, or various lasers (eg, semiconductor laser, helium). Neon laser, argon ion laser, helium cadmium laser, YAG laser), light emitting diode, cathode ray tube, and the like. The light irradiation may be non-polarized light or polarized light. When using polarized light, it is preferable to use linearly polarized light. Furthermore, you may selectively irradiate only the light of a required wavelength using a filter, a wavelength conversion element, etc.

  As for the method using a mask, it is patterned in units corresponding to the sub-pixels corresponding to red, green and blue on a substrate on which a photo-alignment film is formed, or a color filter, and each pattern further includes a plurality of patterns. A pattern mask corresponding to the divided fine region is arranged, and light irradiation is performed as many times as necessary. In light irradiation, it is preferable to irradiate light from an oblique direction of the substrate. The irradiation angle is not particularly limited, and irradiation is performed from a necessary irradiation angle corresponding to each fine region. Generally, it is preferably 5 to 75 degrees with respect to the normal direction of the substrate, and preferably 10 to 60 degrees. Furthermore, for the formation of a nematic hybrid orientation of a clockwise curve or a counterclockwise curve, irradiation is performed from a necessary direction corresponding to each fine region. For example, if a divided region is formed by irradiating light from mirror-symmetrical directions (perpendicular to the layer plane, + α ° (0 <α <90) direction and −α ° direction), the photo-alignment film The nematic hybrid orientations of the optically anisotropic bodies formed on the divided regions also have a clockwise curve and a counterclockwise curve, respectively, and are substantially mirror-symmetric.

  In addition, after irradiating the entire surface from one direction on the substrate on which the photo-alignment film is formed or the color filter, it is patterned in units corresponding to the sub-pixels corresponding to red, green, and blue, Each pattern may be further provided with a pattern mask corresponding to a plurality of divided fine regions, and light irradiation may be performed as many times as necessary. At this time, for the photo-alignment film, for example, a compound having a photo-alignment group that undergoes photoisomerization such as an azo group is preferably used.

  As for the method using the direct drawing by the laser, for example, it can be drawn directly by using the apparatus shown in FIG. FIG. 4 shows an example of a non-polarized oblique irradiation method using a laser. As shown in the figure, laser beams emitted from a plurality of semiconductor lasers (LD1 to LD7) arranged and fixed on the heat dissipation block (64) are collimated lenses (L1 to L1) provided for the respective semiconductor lasers. L7) is converted into parallel light, combined by one combining lens (66) (B1 to B7), and converged at the incident end face of the core (63a) of the multimode optical fiber (63). Then, the surface of the optical alignment film formed on the surface of the substrate or the like is irradiated from a light emitting end portion of the optical fiber (63) from a predetermined direction. Here, as the semiconductor laser, a single-cavity nitride-based compound semiconductor laser in a chip state is preferable, and a GaN-based semiconductor laser is particularly preferable. The wavelength of the light emitted from the semiconductor laser is preferably 350 nm to 800 nm, and particularly preferably 350 nm to 450 nm.

  In the configuration of the optical system described above, a plurality of semiconductor lasers are arranged so that the light emitting points are arranged in a line in a direction parallel to each active layer, and the multiplexing optical system is arranged in the direction in which the light emitting points are arranged. A plurality of collimator lenses provided for each semiconductor laser, and a plurality of laser beams collimated by these collimator lenses. It is desirable that each of the two is combined with a converging lens that converges at the end face of the multimode optical fiber. The plurality of collimator lenses are preferably integrated with each other to form a lens array. On the other hand, it is desirable that the block on which the plurality of semiconductor lasers are mounted is divided into a plurality of pieces and is bonded together to be integrated. In the case where a plurality of semiconductor lasers are arranged in a line, it is desirable that 3 to 10 semiconductor lasers, more preferably 6 or 7 semiconductor lasers are provided. As this semiconductor laser, it is desirable to use one having a light emission width of 1.5 to 5 μm, more preferably 2 to 3 μm.

  As the multimode optical fiber, one having a core diameter of 50 μm or less and NA (numerical aperture) of 0.3 or less is preferably used.

  The multimode optical fiber may be configured using only one multimode optical fiber. Preferably, a plurality of the multimode optical fibers are used, and each of the multimode optical fibers includes a plurality of semiconductor lasers and a multiplexing optical system. Can be combined to emit a high-power laser beam from each multimode optical fiber.

  As examples of a specific configuration of the light source, laser devices such as Japanese Patent Application Laid-Open Nos. 2004-47650, 2004-47651, and 2004-96088 can be referred to.

The laser beam is emitted from the exit end of the multimode optical fiber in a direction inclined at a predetermined angle from the perpendicular to the support surface on which the photo-alignment film is formed, and is incident on the photo-alignment film. Diagonal irradiation can be performed. The angle formed between the perpendicular and the incident direction is preferably 5 to 75 degrees, more preferably 10 to 60 degrees. Irradiation energy per unit area characteristics of the resin depends largely like illumination ^{wavelength, 5mJ / cm 2 ~30J / cm} 2 or so, more preferably from ^{50mJ / cm 2 ~10J / cm 2} .

  Regarding the irradiation of the laser beam, it is possible to irradiate an arbitrary size by scanning the emission end portion or the like. Also, a plurality of multimode optical fibers can be arranged in a one-dimensional array at the exit end. Furthermore, a cylindrical lens or the like may be disposed at the tip of the emission end of the multimode optical fiber as necessary.

  In the above method, the manufacturing method using the photo-alignment film is taken as an example, but of course, the optical anisotropic body of the present invention may be manufactured using a normal alignment film. The alignment film is formed by, for example, rubbing treatment or photo-alignment treatment of an organic compound (including a polymer), oblique deposition of an inorganic compound, formation of a layer having a micro group, or Langmuir-Blodgett method (LB film). It can be provided by means such as the accumulation of organic compounds (for example, ω-triconic acid, dioctadecyldimethylammonium chloride, methyl stearylate, etc.).

Next, in step 3), the composition containing at least the discotic liquid crystalline compound is applied to the surface of the photo-alignment film divided into the divided regions by light irradiation to align the molecules of the discotic liquid crystalline compound. Then, a liquid crystal layer is formed on each surface of the divided region of the photo-alignment film.
The composition contains at least one discotic liquid crystalline compound. Examples of discotic liquid crystalline compounds that can be used in the present invention include various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by the Chemical Society of Japan). , Quarterly Chemistry Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985). J. Zhang et al., J. Am.Chem.Soc., Vol.116, page 2655 (1994)).

  As the discotic liquid crystalline compound, a triphenylene compound, a tri-substituted benzene compound, a hexa-substituted benzene compound, a truxene compound, and the like are preferable, and a triphenylene-based discotic liquid crystal compound and a tri-substituted benzene-based discotic are particularly preferable.

  Further, as the discotic liquid crystal compound, a discotic liquid crystal compound having a polymerizable group or a crosslinking group is particularly preferred. Regarding the discotic liquid crystal compound having a polymerizable group or a crosslinking group, for example, JP-A-2001-4387 is disclosed. And Japanese Patent Application No. 2005-097613.

  The composition may contain additives other than the discotic liquid crystalline compound as necessary. Examples of the additive include a horizontal alignment agent, a wind unevenness inhibitor, a repellency inhibitor, a polymerization initiator, an additive (plasticizer) that lowers the alignment temperature, and a polymerizable monomer. The amount of the additive to be added is not particularly limited as long as it does not impair the liquid crystallinity of the composition, but the total amount is preferably 30% by mass or less, more preferably 15% by mass or less of the constituent components. Hereinafter, each additive will be described.

  The composition may contain a horizontal alignment agent. The horizontal alignment agent means an additive that makes the disk surface, which is the mesogenic core of the discotic liquid crystal compound, parallel to or substantially parallel to the horizontal surface of the support. In this specification, horizontal orientation means that an angle formed with a horizontal plane is less than 10 degrees, and the angle is preferably 0 degrees to 5 degrees, and more preferably 0 degrees to 3 degrees. Specific preferred examples include discotic compounds having a triazine or triphenylene skeleton.

  The composition may contain a wind unevenness inhibitor. As a material for use in combination with a discotic liquid crystalline compound to prevent wind unevenness during coating, a fluorine-based polymer can generally be suitably used. There is no restriction | limiting in particular as a fluorine-type polymer to be used unless the tilt angle change and orientation of a liquid crystalline compound are not inhibited significantly. Examples of fluoropolymers that can be used as wind unevenness inhibitors include Japanese Patent Application Laid-Open No. 2004-198511 (compounds described in paragraphs [0049] to [0057] {[Chemical Formula 20] to [Chemical Formula 28]}), There are descriptions in Japanese Patent Application No. 2003-129354, Japanese Patent Application No. 2003-394998, and Japanese Patent Application No. 2004-12139. By using a discotic liquid crystalline compound and a fluorine-based polymer in combination, an image with high display quality can be displayed without causing unevenness. Furthermore, applicability such as repelling is improved. In order not to inhibit the alignment of the liquid crystalline compound, the amount of the fluorine-based polymer used for the purpose of preventing wind unevenness is preferably in the range of 0.1 to 2% by mass with respect to the liquid crystalline compound. More preferably, it is in the range of 1 to 1% by mass, and still more preferably in the range of 0.4 to 1% by mass.

  The composition may contain a repellency inhibitor. As a material for use together with a discotic liquid crystalline compound to prevent repellency during coating, a polymer compound can generally be suitably used. The polymer to be used is not particularly limited as long as it is compatible with the liquid crystal compound and does not significantly inhibit the tilt angle change or orientation of the liquid crystal compound. Examples of polymers that can be used as repellency inhibitors are described in JP-A-8-95030, and particularly preferred specific polymer examples include cellulose esters. Examples of cellulose esters include cellulose acetate, cellulose acetate propionate, hydroxypropyl cellulose, and cellulose acetate butyrate. In order not to inhibit the alignment of the liquid crystalline compound, the amount of the polymer used for the purpose of preventing repellency is generally preferably in the range of 0.1 to 10% by mass with respect to the liquid crystalline compound. More preferably, it is in the range of 8% by mass, and even more preferably in the range of 0.1-5% by mass.

  The composition may contain a polymerization initiator. The polymerization initiator includes a thermal polymerization initiator and a photopolymerization initiator, and a photopolymerization initiator is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. No. 2,367,661 and US Pat. No. 2,367,670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbons. A substituted aromatic acyloin compound (described in US Pat. No. 2,722,512), a polynuclear quinone compound (described in US Pat. No. 3,046,127, described in US Pat. No. 2,951,758), a triarylimidazole dimer and p-aminophenyl ketone Combination (described in U.S. Pat. No. 3,549,367), acridine and phenazine compound (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compound (described in U.S. Pat. No. 4,221,970) Is included. The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution.

  The composition may contain a polymerizable monomer. The polymerizable monomer that can be used in the present invention is not particularly limited as long as it is compatible with the liquid crystal compound and does not cause a significant change in tilt angle or inhibition of alignment of the liquid crystal compound. Among these, compounds having a polymerization active ethylenically unsaturated group such as a vinyl group, a vinyloxy group, an acryloyl group, and a methacryloyl group are preferably used. The addition amount of the polymerizable monomer is generally in the range of 1 to 50% by mass and preferably in the range of 5 to 30% by mass with respect to the liquid crystal compound. In addition, it is particularly preferable to use a monomer having two or more reactive functional groups because an effect of improving the adhesion between the alignment film and the optically anisotropic layer can be expected.

  The composition may be prepared as a coating solution. As a solvent used for preparing the coating solution, an organic solvent is preferable. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination.

  Application of the coating liquid to the surface of the photo-alignment film can be performed by a known method (for example, spin coating method, wire bar coating method, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method). Moreover, 1-50 mass% is preferable, as for content of the liquid crystalline compound in a coating liquid, 10-50 mass% is more preferable, and 20-40 mass% is more preferable.

  For example, after the composition is prepared as a coating solution, it is applied in the form of a photo-alignment film patterned by light irradiation. Next, heating is performed as necessary, and the discotic liquid crystal is nematic hybrid aligned in a temperature range in which the discotic liquid crystal layer exhibits liquid crystal. The discotic liquid crystalline molecules are arranged in a predetermined nematic hybrid alignment according to the alignment ability expressed in each region on each divided region of the photo-alignment film divided by irradiating light from different irradiation directions. It becomes a state. As a result, the photo-alignment film is patterned into units corresponding to sub-pixels corresponding to red, green and blue by light irradiation, and each pattern is divided into a plurality of divided regions. In addition, the liquid crystal layer formed on the photo-alignment film is also patterned in units corresponding to red, green, and blue subpixels, and each pattern is divided into a plurality of divided regions. .

In the step 4), the liquid crystal layer is cured by a polymerization reaction to obtain an optically anisotropic material. A stable optical anisotropy can be produced by performing polymerization near the temperature at which the liquid crystal composition exhibits liquid crystal and fixing the alignment of the liquid crystal composition. For the polymerization of liquid crystalline molecules, various known crosslinking methods using heat or electromagnetic waves can be employed, but radical polymerization using a photopolymerization initiator using ultraviolet light is particularly preferred. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions.
The thickness of the optical anisotropic body is preferably 0.1 to 20 μm, more preferably 0.5 to 15 μm, and most preferably 1 to 10 μm.

  4) An optical anisotropic body that is patterned into units corresponding to the respective sub-pixels corresponding to red, green, and blue by the process, and each pattern is further configured by a plurality of divided regions. Thus, an optically anisotropic body including discotic liquid crystal molecules in which the divided regions are fixed in a nematic hybrid alignment state is manufactured.

  The optically anisotropic body of the present invention is used by being incorporated in a display element having pixels composed of display areas of three colors of red, green and blue. The optically anisotropic body of the present invention can be incorporated in a display element in a state of being disposed on a substrate. As the substrate, a fine pattern of each color of red, green and blue, that is, a substrate having a color filter layer may be used. In such a case, the optical anisotropic body of the present invention may be disposed on the color filter layer, or the optical anisotropic body of the present invention may be disposed on the surface opposite to the surface on which the color filter layer is formed. You may arrange.

The display element of the present invention includes the optical anisotropic body of the present invention. Hereinafter, a display element according to an embodiment of the present invention will be described.
(Display element)
FIG. 5 is a schematic cross-sectional view of an example of the liquid crystal display element 20 having the optical anisotropic body 11 of the present invention. The example of FIG. 5 is a display device having the liquid crystal cell 40, the polarizing plate 30 and the backlight unit 50 on both sides of the liquid crystal cell 40.

  The liquid crystal cell 40 includes a pair of counter substrates 41 and a liquid crystal 45 disposed in the counter substrates 41. A TFT drive element 46 is disposed on one of the pair of counter substrates 41. Between the counter substrate 41, a color filter 42, a transparent electrode layer 44, and an alignment layer 43 having sub-pixels corresponding to display areas of three colors of red 42R, green 42G, and blue 42B are arranged.

  The polarizing plate 30 includes two substrates (protective layers) 31 and 33 and a polarizing layer 32 sandwiched between the substrates. The backlight unit 50 includes a light guide plate 52, a diffusion plate 51, and a light source 53.

  In the display element 20 shown in FIG. 5, the optical anisotropic body 11 of the present invention can be used as a member constituting the polarizing plate 30. For example, as the upper and lower polarizing plates, a polarizing plate 30 having a protective layer in which the optically anisotropic body 11 of the present invention is disposed on a substrate made of a polymer film or the like is used so that the protective layer is on the liquid crystal cell side. It may be incorporated. The optically anisotropic body 11 is patterned in units corresponding to the sub-pixels (14, 15, 16) corresponding to red, green, and blue, and each pattern is further divided into a plurality of fine regions. (For example, 14a, 14b, 15a, 15b, 16a, 16b).

FIG. 6 shows another embodiment of the liquid crystal display element of the present invention.
In FIG. 6, the same members as those of FIG. The liquid crystal display element shown in FIG. 6 has the optical anisotropic body 11 of the present invention in the liquid crystal cell. By using the substrate having the color filter layer 42 and the optically anisotropic body 11 of the present invention on the glass substrate as the substrate of the upper liquid crystal cell, the optically anisotropic body 11 can be incorporated into the liquid crystal cell. .

The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.
[Example 1]
A 1% dimethylformamide solution of photoalignable compound A-1 (synthesized by the method described in JP-A-2004-83810) is used to prepare a photoalignment film coating solution, and the coating solution is spin-coated on a glass substrate. (20 seconds at 2000 rpm) to form a photo-alignment film.
Then, the substrate on which the photo-alignment film was formed was irradiated with ultraviolet rays of 150 mW for 100 seconds from an angle of 45 degrees with respect to the normal to the substrate by an ultraviolet irradiation device. Subsequently, a halftone dot pattern of 100 μm square was placed on the substrate coated with the photo-alignment film, and 150 mW ultraviolet rays were irradiated again for 100 seconds from an angle of −45 degrees with respect to the normal to the substrate.

Next, a liquid crystal composition coating liquid having the composition shown below is applied onto the photo-aligned film subjected to light irradiation by spin coating (2000 rpm for 20 seconds) and heated at a film surface temperature of 130 ° C. to form a nematic hybrid. Oriented. Thereafter, a patterned optical anisotropy was produced by irradiating 0.4 J / cm ² ultraviolet rays while maintaining the same temperature to fix the alignment state of the liquid crystal layer. The thickness of the formed optical anisotropic body was 1.5 μm.

────────────────────────────────────
Liquid crystal composition coating solution ─────────────────────────────────────
The following discotic liquid crystalline compound D-1 100 parts by mass Ethylene oxide-modified trimethylolpropane triacrylate (V # 360, manufactured by Osaka Organic Chemical Co., Ltd.) 9.9 parts by mass Photopolymerization initiator 3.3 parts by mass (Irgacure 907, manufactured by Ciba Specialty Chemicals Co., Ltd.)
Sensitizer (Kayacure-DETX, manufactured by Nippon Kayaku Co., Ltd.) 1.1 parts by weight Methyl ethyl ketone 300 parts by weight ───────────────────────── ───────────

The discotic liquid crystalline compound is described in Polym. Adv. Technol. 11 and 398 (2000).
The substrate on which the optical anisotropy is formed is horizontal in the diagonal position (FIG. 7), tilted to the right by 10 degrees (FIG. 8), and tilted to the left by 10 degrees (FIG. 7). In FIG. 9, slice observation was performed with a polarizing microscope (ECLIP E600W POL manufactured by Nikon). As is clear from the observation results shown in FIGS. 7 to 9, it is confirmed that it has a fine structure composed of a nematic hybrid orientation with a clockwise curve and a nematic hybrid orientation with a counterclockwise curve according to the pattern of the photo-alignment film. did. Furthermore, it was confirmed that the tilt angle on the alignment film side was approximately 30 degrees.
As a result of measuring the optical characteristics with KOBRA · 21ADH (manufactured by Oji Scientific Instruments), Re, which is the front retardation at a wavelength of 589 nm, is 64 nm, and Re is a retardation measured from a direction inclined by 40 degrees from the normal direction of the substrate (Re ( 40) was 66 nm, and Re (−40) as a retardation measured from a direction inclined by −40 degrees from the normal direction of the substrate was 63 nm.
From this result, by forming a microstructure consisting of a nematic hybrid orientation with a clockwise curve and a nematic hybrid orientation with a counterclockwise curve, the optical characteristics from the facing direction are averaged, and the viewing angle characteristics based on the hybrid orientation are improved. I was able to confirm that I could do it.

[Example 2]
A photo-alignment film was formed on the glass substrate in the same manner as in Example 1. The obtained sample was placed on the stage with the alignment layer side up. As shown in FIG. 4, laser beams (laser beam wavelength: 406 nm) emitted from seven GaN-based semiconductor lasers (LD1 to LD7) arrayed and fixed on the heat dissipation block (65) are applied to each semiconductor laser. Are collimated by collimator lenses (L1 to L7) provided on the optical fiber, converged to a multimode optical fiber (63) by one combining lens (66), and turned into a cylindrical lens (62) disposed at the exit end. Then, the substrate (12) coated with the photo-alignment film (13) was irradiated from a direction forming an angle of 45 degrees or -45 degrees from the normal direction. At this time, the stage was scanned and irradiated with light so that the irradiation energy per unit area was uniformly 5 J / cm ² and one pattern was 20 μm square.
Next, a liquid crystal composition coating solution was applied by the same method as in Example 1, the nematic hybrid alignment was fixed by polymerization, and an arbitrarily patterned optical anisotropy was produced.

[Example 3]
A photoalignment film was formed on a glass substrate by spin coating (2000 rpm for 20 seconds) using a 1% dimethylformamide solution of photoalignment compound A-2 shown below as a photoalignment film coating solution.

なお、上記光配向性化合物は、Macromol. Symp.、第１３７巻、１２９頁（１９９９）に記載の方法により合成した。

The photo-alignment compound was synthesized by the method described in Macromol. Symp., Vol. 137, p. 129 (1999).

Then, the substrate on which the photo-alignment film was formed was irradiated with 150 mW ultraviolet rays for 150 seconds from an angle of 45 degrees with respect to the normal to the substrate by an ultraviolet irradiation device. Subsequently, a halftone dot pattern of 100 μm square was placed on the substrate coated with the photo-alignment film, and 150 mW ultraviolet rays were irradiated again for 150 seconds from an angle of −45 degrees from the normal to the substrate.
Next, a liquid crystal composition coating solution was applied by the same method as in Example 1, the nematic hybrid alignment was fixed by polymerization, and an arbitrarily patterned optical anisotropy was produced. The thickness of the formed optical anisotropic body was 1.5 μm. As a result of measuring the optical characteristics with KOBRA · 21ADH (manufactured by Oji Scientific Instruments), Re, which is a front retardation at a wavelength of 589 nm, is 27 nm, and Re is a retardation measured from a direction inclined by 40 degrees from the normal direction of the substrate (Re ( 40) was 44 nm, and Re (−40) as a retardation measured from a direction inclined by −40 degrees from the normal direction of the substrate was 47 nm.
Furthermore, the result of the slice observation with a polarizing microscope (Nikon ECLIPE E600W POL) was performed, and it was confirmed that it had a fine structure composed of a nematic hybrid orientation with a clockwise curve and a nematic hybrid orientation with a counterclockwise curve. Further, it was confirmed that the tilt angle on the alignment film side was approximately 7 degrees.
From this result, by forming a microstructure consisting of a nematic hybrid orientation with a clockwise curve and a nematic hybrid orientation with a counterclockwise curve, the optical characteristics from the facing direction are averaged, and the viewing angle characteristics based on the hybrid orientation are improved. I was able to confirm that I could do it.

[Comparative Example 1]
A photo-alignment film was formed on the glass substrate in the same manner as in Example 1. Then, the substrate on which the photo-alignment film was formed was irradiated with ultraviolet rays of 150 mW for 100 seconds from an angle of 45 degrees with respect to the normal to the substrate by an ultraviolet irradiation device.
Next, a liquid crystal composition coating solution was applied by the same method as in Example 1, and the nematic hybrid alignment was fixed by polymerization to produce an optically anisotropic material. The thickness of the formed optical anisotropic body was 1.5 μm.
As a result of measuring the optical characteristics with KOBRA · 21ADH (manufactured by Oji Scientific Instruments), Re is a front retardation at a wavelength of 589 nm, 62 nm, and Re is a retardation measured from a direction inclined by 40 degrees from the normal direction of the substrate (Re ( 40) was 105 nm, Re (−40), which was retardation measured from a direction inclined by −40 degrees from the normal direction of the substrate, was 21 nm, and the optical characteristics from the facing direction were asymmetric.

It is a schematic sectional drawing for demonstrating the optically anisotropic body of this invention. FIG. 2 is a schematic diagram schematically showing the orientation of discotic liquid crystal molecules in one divided region constituting the optically anisotropic body of the present invention, and is a schematic diagram showing the orientation of molecules that are nematic hybrid aligned by a counterclockwise curve. . FIG. 2 is a schematic diagram schematically showing the orientation of discotic liquid crystal molecules in one divided region constituting the optically anisotropic body of the present invention, and is a schematic diagram showing the orientation of molecules that are nematic hybrid aligned with a clockwise curve. . It is a top view which shows the example of the combining laser light source used for diagonal light irradiation which can be used for this invention. It is a schematic sectional drawing of an example of the liquid crystal display device containing the optically anisotropic body of this invention. It is a schematic sectional drawing of the other example of the liquid crystal display device containing the optically anisotropic body of this invention. It is a polarization microscope observation result in the diagonal position of the optically anisotropic body of this invention in Example 1. FIG. It is a polarizing microscope observation result when the optically anisotropic body of this invention in Example 1 is inclined 10 degree | times with respect to the horizontal in diagonal position. It is a polarizing microscope observation result when the optically anisotropic body of this invention in Example 1 inclines -10 degree | times with respect to the horizontal in diagonal position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Optical anisotropic body 12 Substrate 13 Orientation layer 14 Pattern 14a corresponding to the sub-pixel corresponding to red Fine area 14b divided in the red pattern Other fine area 15 divided in red pattern Sub-corresponding to green Pattern 15a corresponding to pixel Fine area 15b divided in green pattern Another fine area 16 divided in green pattern Pattern 16a corresponding to sub-pixel corresponding to blue Fine area 16b divided in blue pattern Green Discrete liquid crystal molecules 20 Liquid crystal display device 30 Polarizing plate 31 Protective layer 32 Polarizer 33 Protective layer 40 Liquid crystal cell 41 Transparent substrate 42 Color filter 43 Transparent electrode layer 44 Alignment layer 45 Liquid crystal 46 TFT
47 Black matrix 50 Backlight part 51 Diffuser plate 52 Light guide plate 53 Light source 61 Stage 62 Cylindrical lens 63 Multimode optical fiber 63a Core of multimode optical fiber 64 Submount 65 Heat block 66 Combined lens LD1-7 GaN semiconductor laser L1 ~ 7 Collimator lens B1 ~ 7 Laser beam A Angle from the vertical direction to the support (incident angle)
B Combined laser beam

Claims (13)

An optically anisotropic body used by being incorporated in a display element having a pixel composed of display areas of three colors of red, green and blue,
It is patterned into units corresponding to each of the sub-pixels corresponding to red, green and blue, and each patterned unit is composed of a plurality of divided regions, and each divided region has a discotic liquid crystal molecule. An optical anisotropy containing. The optically anisotropic body according to claim 1, wherein the discotic liquid crystal molecules are fixed in a nematic hybrid alignment state in the divided region. A molecule formed in the thickness direction of molecules fixed in the nematic hybrid alignment state of at least one of the divided regions and a nematic hybrid alignment state of the other one of the divided regions are fixed. The optical anisotropic body according to claim 2, wherein the curves formed by molecules in the thickness direction are different from each other. The curve formed in the thickness direction by molecules fixed in the nematic hybrid orientation state of at least one of the divided regions is a counterclockwise curve, and the nematic hybrid of the other one of the divided regions The optically anisotropic body according to claim 2 or 3, wherein a curve formed in the thickness direction by molecules fixed in an oriented state is a clockwise curve. The optically anisotropic body according to claim 2, wherein nematic hybrid orientations of at least two adjacent divided regions are substantially mirror-symmetric with each other. The optically anisotropic body according to any one of claims 1 to 5, wherein the plurality of divided regions are 2 to 8 regions. The optically anisotropic body according to any one of claims 1 to 6, wherein each side of the divided region has a length of 0.1 µm to 200 µm. The optically anisotropic body according to any one of claims 1 to 7, wherein each of the divided regions is a region formed from a composition containing a discotic liquid crystalline compound having a polymerizable group or a crosslinkable group. . The optical element which has a board | substrate and the optically anisotropic body of any one of Claims 1-8 arrange | positioned on this board | substrate. The optical element which has a board | substrate which has a fine pattern of each color of red, green, and blue, and the optical anisotropic body of any one of Claims 1-8 arrange | positioned on this board | substrate. A display element comprising the optical anisotropic body according to claim 1, or the optical element according to claim 9 or 10. A method for producing an optically anisotropic material used by being incorporated in a display element having pixels composed of display areas of three colors of red, green and blue,
1) a step of forming a photo-alignment film on a substrate or a color filter;
2) A step of irradiating the photo-alignment film with light to form a pattern corresponding to each sub-pixel corresponding to red, green and blue, and dividing each pattern into a plurality of divided regions;
3) Applying a composition containing a discotic liquid crystalline compound to the surface of the photo-alignment film that has been irradiated with light and divided into a plurality of divided regions, aligns the molecules of the discotic liquid crystalline compound, and A step of forming a liquid crystal layer on each surface of the divided region of the alignment film, and 4) a step of curing the liquid crystal layer by a polymerization reaction,
The manufacturing method of the optically anisotropic body containing this. In the step 2) of irradiating the photo-alignment film with light, a laser beam obtained by combining a plurality of laser beams respectively emitted from a plurality of semiconductor lasers is irradiated with light through a multimode optical fiber. Item 13. A method for producing an optically anisotropic material according to Item 12.

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