JP2005107417A - Substrate for liquid crystal alignment, its manufacturing method, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device of a multi-domain system which has excellent display characteristics and can be manufactured at low costs. <P>SOLUTION: An alignment layer 9 aligning directors of liquid crystal molecules along the normal direction of a substrate 1 is formed on one surface of the substrate 1, oblique alignment regulating regions aligning the directors of the liquid crystal molecules obliquely to the normal direction of the substrate are formed in the individual regions corresponding to pixels in the alignment layer 9, and a flattening film 8 is formed in a position corresponding to a border between the oblique alignment regulating region and the alignment layer 9 where no oblique alignment regulating region is formed between the substrate 1 and the alignment layer 9. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal alignment substrate, a manufacturing method thereof, and a liquid crystal display device, and more particularly to a liquid crystal alignment substrate suitable for a multi-domain liquid crystal display device, a manufacturing method thereof, and a liquid crystal display device.

  The liquid crystal display device is one of flat panel displays that can be easily reduced in thickness and driven at a low voltage. Today, various liquid crystal display devices having different structures and operation modes have been developed.

  As a typical liquid crystal display device, a normally white mode TN (twisted nematic) type liquid crystal display device is widely known. The manufacturing technology of TN type liquid crystal display devices has made remarkable progress, and active matrix drive type TN type liquid crystal display devices surpass CRT (CRT) in terms of contrast and color reproducibility when viewed from the front. Has reached. However, the TN type liquid crystal display device has a major drawback that the viewing angle is narrow (the viewing angle dependency is large).

  In recent years, IPS (In-Plane-Switching) type liquid crystal display devices and multi-domain vertical alignment type liquid crystal display devices have been developed as liquid crystal display devices with small viewing angle dependency characteristics. It has been put to practical use as a TV.

  However, an IPS liquid crystal display device is difficult to improve response speed and high definition, and it is difficult to improve productivity because optical characteristics are highly dependent on cell thickness. On the other hand, the vertical alignment type liquid crystal display device is a normally black mode liquid crystal display device using the birefringence of liquid crystal molecules, and it is easy to increase the display contrast and the black level response speed compared with the TN type liquid crystal display device. Since it has the advantage that it is easy to make it faster, it is attracting more attention than the IPS liquid crystal display device today.

  Here, as is well known, the multi-domain liquid crystal display device is so arranged that a large number of liquid crystal molecules included in each pixel region in a plan view are divided at least during halftone display. A liquid crystal display device configured to be divided into a plurality of regions having different orientation directions in plan view.

  When an alignment film is produced by rubbing the alignment film, a multi-domain liquid crystal is formed by forming a plurality of fine regions having different rubbing directions in each of the regions corresponding to the pixels on the surface of the alignment film. An alignment film applicable to a display device can be obtained. However, in this case, a plurality of masks are required, and further, a cleaning process for removing dust generated by the rubbing process is required.

  As a multi-domain vertical alignment type liquid crystal display device that does not require a rubbing process in forming an alignment film, for example, in Patent Document 1, an opening is provided at a predetermined position of a counter electrode, that is, a position facing a central portion of a pixel electrode. Thus, a liquid crystal display device is described in which liquid crystal molecules are aligned and divided in two or four directions.

  Patent Document 2 discloses a structure having a specific shape, that is, a serrated continuous concave-convex structure surface, and the concave-convex structure surface is higher in the center of the pixel and lower toward the end of the pixel. A vertical alignment type liquid crystal display device is described in which a structure including a unit or a structure unit having a pixel end portion that is high and lower toward the center portion of the pixel is provided as an alignment film. In this vertical alignment type liquid crystal display device, a plurality of inclined surfaces having different inclination directions due to the presence of the structure are formed on the entire alignment film in each pixel region, and the alignment direction of the liquid crystal molecules on the inclined surface is the same as that of the inclined surface. Since it is regulated by the tilt direction, the liquid crystal molecules are aligned and divided in a plurality of directions in each pixel region.

Patent Document 3 discloses a vertical alignment type liquid crystal display device in which a structure (film) in which a plurality of convex portions or concave portions are formed per pixel is provided on an electrode, and a vertical alignment film that does not require rubbing is formed thereon. Is described. In this vertical alignment type liquid crystal display device as well, as in the vertical alignment type liquid crystal display device described in Patent Document 2, a plurality of inclined surfaces having different inclination directions due to the presence of the structure are formed on the entire alignment film in each pixel region. Since the alignment direction of the liquid crystal molecules on the inclined surface is regulated by the inclination direction of the inclined surface, the liquid crystal molecules are aligned and divided in a plurality of directions in each pixel region. Further, in Patent Document 3, in addition to providing the above-described structure, a slit is provided in a predetermined portion of the counter electrode, and the voltage is the same as in the vertical alignment type liquid crystal display device described in Patent Document 1 described above. It is also described that a portion where the electric field is inclined may be generated during application.
JP-A-6-301036 JP 7-199193 A Japanese Patent Laid-Open No. 11-242225

  However, the vertical alignment type liquid crystal display device described in Patent Document 1 has a problem that the response speed is relatively slow. In particular, the alignment of each liquid crystal molecule is applied from a state where no voltage is applied. There is a problem that the response speed when changing is slow.

  In the vertical alignment type liquid crystal display device described in Patent Document 2, the above-described inclined surface formed in each pixel extends over the entire pixel, and when no voltage is applied, all the liquid crystal on the inclined surface is present. Since alignment is performed along the inclined surface, there is a problem that complete black display cannot be obtained and the contrast is lowered.

  In addition, in the vertical alignment type liquid crystal display device described in Patent Document 2, in order to sufficiently regulate the alignment direction of the liquid crystal molecules, it is necessary to make the above-described inclined surface steep, and for that purpose, as described above. Other problems also arise because the structure needs to be thick. That is, in Patent Document 2, a resist is cited as a material of the structure. However, since the resist is a dielectric, if the structure made of a dielectric is thickened, the structure is not affected during the operation of the liquid crystal display device. As a result, a phenomenon in which the orientation direction of liquid crystal molecules does not change even when a voltage is applied between the electrodes due to the charge accumulated in the structure, that is, a so-called burn-in phenomenon is likely to occur.

  Furthermore, in order to form the above-described structure described in Patent Document 2, steps such as resist coating, pre-baking, exposure, development, and post-baking must be added, which increases manufacturing costs. .

  The occurrence of the image sticking phenomenon and the increase in manufacturing cost are also problematic in the vertical alignment type liquid crystal display device described in Patent Document 3 using the structure (film) described above. Patent Document 3 describes that the occurrence of seizure phenomenon can be suppressed by forming a large number of fine holes in the above-mentioned structure, but the formation of such fine holes further increases the manufacturing cost. I will.

  A first object of the present invention is to provide a liquid crystal alignment substrate that makes it possible to manufacture a multi-domain liquid crystal display device excellent in display characteristics at low cost.

  A second object of the present invention is to provide a method for producing a liquid crystal alignment substrate that makes it possible to produce a liquid crystal display device having excellent display characteristics at low cost.

  A third object of the present invention is to provide a multi-domain liquid crystal display device capable of manufacturing a display having excellent display characteristics at low cost.

  Regarding the wettability (surface energy) of the substrate interface and the alignment state of liquid crystal molecules, a relationship represented by the formula Δγ = γS−γL has been found (LT. Creagh and ARKmetz: SID1972, International Symposium. Digest, P.90 (1972)). Here, γS in the formula represents the critical surface energy of the solid, γL represents the surface free energy of the liquid, and the liquid crystal molecules are in the vertical alignment when Δγ> 0, and in the horizontal alignment when Δγ <0. Therefore, for example, the negative liquid crystal is vertically aligned when the alignment film surface is hydrophobic and horizontally aligned when the surface of the alignment film is hydrophilic.

  Based on this knowledge, the present inventors obtained the idea of producing a multi-domain liquid crystal display device by forming a hydrophobic region and a hydrophilic region on the alignment film surface, and completed the present invention. It came.

  The liquid crystal alignment substrate of the present invention that achieves the first object is a liquid crystal alignment substrate used in a display liquid crystal panel of a multi-domain liquid crystal display device, wherein a director of liquid crystal molecules is provided on one side of the substrate. Inclination alignment regulation in which an alignment film is formed to be aligned along the normal direction, and the directors of liquid crystal molecules are inclined with respect to the substrate normal direction in individual regions corresponding to the pixels in the alignment film. And a planarizing film at a position corresponding to a boundary between the substrate and the alignment film and at least the inclined alignment regulating region in which the inclined alignment regulating region is not formed. Is formed.

  According to the present invention, since the tilt alignment regulating region is formed in each of the alignment films corresponding to the pixels, the liquid crystal molecules on the tilt alignment regulating region are turned on when the power is turned on (when voltage is applied). Tilts ahead of the liquid crystal molecules on the alignment film. At this time, the liquid crystal molecules on the tilt alignment regulating region are tilted along the boundary with the alignment film on which the tilt alignment regulating region is not formed, and the liquid crystal molecules on the alignment film are started from the liquid crystal molecules on the tilt alignment regulating region. The molecule tilts. Therefore, the response when the voltage is on can be made faster. However, for example, when the surface of the alignment film becomes uneven due to a color filter array or the like formed on the substrate, the liquid crystal molecules may be inclined and aligned in a direction that is not predicted in advance. In this case, when the power is turned on, the liquid crystal molecules may be inclined in a direction that is not a desired direction. However, in the present invention, since the planarization film is provided, the inclination direction of the liquid crystal molecules can be controlled. . In addition, since the alignment film in which the inclined alignment control region is formed can be obtained by subjecting the surface of the alignment film to a hydrophilic treatment as will be described later, it can be relatively easily manufactured at low cost. . In addition, since it is not necessary to make the alignment film particularly thick, the occurrence of the image sticking phenomenon can be easily suppressed.

  In the liquid crystal alignment substrate of the present invention, the planarization film is formed on an electrode formed on one side of the substrate, the alignment film is a hydrophobic region, and the tilt alignment regulating region is a hydrophilic region. Is preferable.

  The method for manufacturing a liquid crystal alignment substrate of the present invention that achieves the second object is a method for manufacturing a liquid crystal alignment substrate used for a display liquid crystal panel of a multi-domain liquid crystal display device, wherein the electrode is provided on one side. A step of preparing a substrate on which the substrate is formed, a step of forming a planarization film on the electrode, a step of forming an alignment film on the planarization film, and a hydrophilic treatment selectively on the surface of the alignment film And forming an inclined alignment regulating region in which the director of the liquid crystal molecules is inclined with respect to the substrate normal direction in each region corresponding to the pixel in the surface of the alignment film. It is characterized by including.

  According to the present invention, the alignment film is formed on the electrode through the planarization film, and the surface of the alignment film is selectively subjected to a hydrophilic treatment, whereby the liquid crystal alignment of the present invention is performed. A substrate can be obtained. As a result, a liquid crystal alignment substrate can be efficiently produced, yield can be prevented from decreasing, and costs can be reduced.

  In the manufacturing method of the liquid crystal aligning substrate of this invention, it is preferable that the said hydrophilic treatment is performed by the exposure process using the mask which has a photocatalyst layer, and a photocatalyst is included in the said alignment film.

  According to these inventions, it is possible to use ultraviolet light having a relatively long wavelength as the exposure light, so that a relatively inexpensive light source device for exposure light can be used. As a result, it becomes easy to suppress the manufacturing cost of the liquid crystal alignment substrate.

  The liquid crystal display device of the present invention that achieves the third object is a multi-domain liquid crystal display device in which a liquid crystal molecule is formed on one surface of one or both of two substrates constituting a display liquid crystal panel. An alignment film is formed to align the director of the liquid crystal along the normal direction of the substrate, and the director of liquid crystal molecules is inclined with respect to the normal direction of the substrate in each of the alignment films corresponding to the pixels. An inclined alignment regulating region to be formed, and at a position corresponding to a boundary between the substrate and the alignment film and at least the alignment film in which the inclined alignment regulating region is not formed. A flattening film is formed.

  The liquid crystal display device of the present invention is a multi-domain liquid crystal display device using the liquid crystal alignment substrate of the present invention described above as one or both of the two liquid crystal alignment substrates constituting the display liquid crystal panel. . Therefore, the liquid crystal display device of the present invention can manufacture a liquid crystal display device capable of controlling the tilt direction of liquid crystal molecules by an extremely easy process and at a low cost.

  In the liquid crystal display device of the present invention, the planarizing film is formed on an electrode formed on one side of the substrate, the alignment film is a hydrophobic region, and the tilted alignment regulating region is a hydrophilic region. Is preferable.

  As described above, according to the liquid crystal alignment substrate of the present invention, when the power is turned on due to the unevenness of the surface of the alignment film, the liquid crystal molecules may be inclined in a direction that is not a desired direction. In the present invention, since the planarization film is formed and the alignment film is formed thereon, the tilt direction of the liquid crystal molecules can be controlled. In addition, since the alignment film in which the tilted alignment regulating region is formed can be obtained, for example, by subjecting the surface of the alignment film to a hydrophilic treatment, it can be manufactured relatively easily at a low cost. In addition, since it is not necessary to make the alignment film particularly thick, the occurrence of the image sticking phenomenon can be easily suppressed.

  According to the method for producing a liquid crystal alignment substrate of the present invention, the hydrophilic region can be formed by exposure treatment, and thus the production cost can be easily suppressed.

  According to the liquid crystal display device of the present invention, since the liquid crystal panel for display is formed using the liquid crystal alignment substrate of the present invention described above, a liquid crystal display device capable of controlling the tilt direction of liquid crystal molecules is extremely easy. It can be manufactured by a simple process and can be manufactured at low cost.

  First, the features of the present invention will be described in more detail.

  A feature of the present invention is that an alignment layer is formed in the alignment film so as to align the director of liquid crystal molecules with respect to the normal direction of the substrate, and at least the inclined alignment control region between the substrate and the alignment film. The flattening film is formed at a position corresponding to the boundary with the alignment film in which the inclined alignment regulating region is not formed. The reason why the present invention is configured in this way is that an inclined alignment regulating region is formed in the alignment film, so that when the power is turned on (when voltage is applied), the liquid crystal molecules on the inclined alignment regulating region are on the alignment film. The liquid crystal molecules are tilted prior to the liquid crystal molecules, and the liquid crystal molecules on the alignment film (alignment film in which the tilt alignment control region is not formed) tilts starting from the liquid crystal molecules on the tilt alignment control region. However, for example, when the surface of the alignment film is uneven due to a color filter array or the like formed on the substrate, for example, the liquid crystal molecules on the tilt alignment control region are tilted in a direction that is not predicted in advance. In this case, when the power is turned on, the liquid crystal molecules are inclined in a direction other than the desired direction, and an alignment film (an inclined alignment regulating region is formed due to the inclination of the liquid crystal molecules. If the liquid crystal molecules on the alignment layer are not tilted, the tilt direction of the liquid crystal molecules cannot be controlled, and for example, the viewing angle may be deteriorated.

  In the present invention, the planarization film is formed at a position corresponding to the boundary between the substrate and the alignment film and at least the alignment film where the inclined alignment control region is not formed. When the power is turned on, the liquid crystal molecules on the alignment film in which the tilt alignment control region is not formed are caused by the tilt direction of the liquid crystal molecules on the boundary between the tilt alignment control region and the alignment film in which the tilt alignment control region is not formed. Therefore, the tilt direction of the liquid crystal molecules can be controlled, and there is no need to worry about, for example, the viewing angle becoming worse. That is, when the power is turned on, the liquid crystal molecules are tilted from what corresponds to the boundary between the tilted alignment control region and the alignment film where the tilted alignment control region is not formed. First, the liquid crystal molecules on the boundary are tilted, and other liquid crystal molecules are tilted due to the tilted liquid crystal molecules. Therefore, by forming a planarization film at least at the position corresponding to the boundary, the liquid crystal molecules It is possible to control the inclination direction of the image, and there is no need to worry that the viewing angle or the like deteriorates, for example.

  Further, the surface of the alignment film when the planarizing film is formed is preferably 6 ° or less, more preferably 5 ° or less, and particularly preferably the angle θ of the director of the liquid crystal molecules is perpendicular to the substrate normal direction. Is preferably formed to be 3 ° or less. When the angle θ exceeds 6 °, the director of the liquid crystal molecules in that portion tilts by more than 6 ° with respect to the normal direction of the substrate, so that light leakage may occur particularly when the liquid crystal is displayed in black. It is not preferable from the viewpoint of contrast.

  That is, as shown in FIG. 1, a liquid crystal cell 700 in which liquid crystal 703 having a thickness d in which directors of liquid crystal molecules are uniformly arranged between two substrates 701 and 702 is considered, and the inclination of the director of the liquid crystal molecules 704 is considered. (Azimuth angle (also referred to as tilt angle)) The relationship between α and transmittance is calculated. At this time, ψ is an incident angle, and when ψ = 0 is calculated, the front transmittance can be calculated.

  The phase difference δ (ψ) generated in the transmitted light is given by the equation (1), and the relationship between the phase difference δ (ψ) and the transmittance T (ψ) is given by the equation (2). ) And equation (2) (TJ Schehher and J. Nehring J. Appl. Phys., No 5. May 1977 (reference)).

Here, since c ² = a ² cos ² α + b ² sin ² α, a = 1 / ne, b = 1 / no, the thickness d of the liquid crystal, the refractive index no for ordinary light, the refractive index ne for extraordinary light, and If the wavelength λ is known, the transmittance of the liquid crystal can be calculated.

  For example, MLC-6608 (ne = 1.5586, no = 1.4757) manufactured by Merck is used as the vertical alignment liquid crystal, and the pretilt when the liquid crystal thickness (d) is 4 μm and the wavelength (λ) is 550 nm. The relationship between corners and light leakage (%) (transmittance) is as shown in FIG.

  Further, the maximum contrast ratio is obtained from the luminance for black display at this time, and the relationship between the maximum contrast ratio and the pretilt angle is as shown in FIG.

  In particular, the light leakage at the time of black display is less than 0.1% because the display becomes thin when it exceeds 0.1%, and a good display state is obtained when it is particularly 0.05% or less. In addition, the maximum contrast ratio is preferably 500 or more particularly considering image quality.

  Therefore, the pretilt angle satisfying these conditions is 84 ° or more, preferably 85 ° or more, more preferably 87 ° or more, as shown in FIGS.

  In the liquid crystal alignment substrate of the present invention, when an empty cell is prepared using at least one sheet and a negative type liquid crystal is filled in the cell, a vertical electric field type display liquid crystal display panel is manufactured. When no voltage is applied between the substrates, liquid crystal molecules on the hydrophobic region of the alignment film in each pixel region (liquid crystal molecules that completely overlap the hydrophobic region when the display liquid crystal panel is viewed in plan view) Means the liquid crystal molecules on the hydrophilic region that is the tilt alignment regulating region of the alignment film (liquid crystal molecules that completely overlap with the hydrophilic region when the display liquid crystal panel is viewed in plan). Means the same, and so on) is intended to be tilted or horizontally oriented. However, the liquid crystal is an elastic body, and local alignment distortion becomes a factor that increases internal energy. For this reason, when orientation distortion arises locally, it tries to maintain the stability by correcting the distortion. As a result, if either one of the hydrophobic region and the hydrophilic region that is the tilted alignment regulating region is sufficiently smaller than the other, the action of the larger region becomes dominant, and the liquid crystal molecules are substantially omitted. Orient uniformly. That is, in each pixel region, the hydrophobic region is sufficiently larger than the hydrophilic region (an inclined alignment regulating region; the same applies hereinafter), so that the liquid crystal molecules are aligned substantially uniformly when no voltage is applied. In other words, it is possible to obtain a vertical alignment type liquid crystal panel for display with good black display and high display contrast.

  Further, in this display liquid crystal panel, the liquid crystal molecules on the tilt alignment regulating region are in a state of being easily tilted or horizontally aligned. Therefore, when a voltage is applied between the upper and lower substrates, the liquid crystal molecules on the tilt alignment regulating region are First, tilt alignment is performed. And since the deformation of the liquid crystal accompanying the tilted alignment is also propagated to the liquid crystal on the hydrophobic region, in combination with the voltage application, all the liquid crystal molecules can be moved in a relatively short time in the liquid crystal molecules in the hydrophobic region. The director can be tilted along the tilt alignment regulating region.

  Next, the substrate for aligning liquid crystal, the method for manufacturing the substrate for aligning liquid crystal, and the liquid crystal display device of the present invention will be sequentially described with reference to the drawings.

1. Liquid crystal alignment substrate and alignment film (first embodiment)
FIG. 4A schematically shows a planar arrangement of the constituent members in the liquid crystal alignment substrate according to the first embodiment of the present invention, and FIG. 4B shows the II line shown in FIG. A cross section is shown schematically.

  The liquid crystal alignment substrate 10 shown in the figure is used as a substrate on the display surface side of a display liquid crystal panel in an active matrix driving type vertical alignment liquid crystal display device using negative liquid crystal. The liquid crystal alignment substrate 10 includes a translucent substrate 1, a color filter array 3, a light shielding layer (black matrix) 5, a transparent electrode pattern 7, a planarizing film 8 and an alignment film 9.

  The color filter array 3 and the light shielding layer 5 are formed on one side of the translucent substrate 1, and the transparent electrode pattern 7 covers the transparent filter pattern 7 and the planarizing film 8 covers the transparent electrode pattern 7. Further, an alignment film 9 is formed on the planarizing film 8. In FIG. 4A, the transparent electrode pattern 7, the planarizing film 8, and the alignment film 9 are not shown in order to make the arrangement of the color filter array 3 and the light shielding layer 5 easy to understand.

  The translucent substrate 1 is formed of, for example, glass or transparent plastic, and the color filter array 3 is formed by arranging a number of color filters of a desired color under a certain pattern. Each color filter can be formed of, for example, a resin (color resin) containing or dispersing a dye or pigment.

  The substrate 10 for liquid crystal alignment stripes a red color filter 3R formed of a red color resin, a green color filter 3G formed of a green color resin, and a blue color filter 3B formed of a blue color resin. The color filter array 3 is formed by arranging in a shape. Each of the color filters 3R, 3G, and 3B corresponds to one pixel. One red color filter 3R, the adjacent green color filter 3G, and the adjacent blue color filter 3B constitute one picture element.

  The light-shielding layer 5 prevents the color filter array 3 from being leaked from the pixels in the display liquid crystal panel (leakage light) or the optical elements of the active matrix drive type display liquid crystal panel. It arrange | positions around each color filter 3R, 3G, 3B which comprises. The light shielding layer 5 can be formed of a metal thin film having a light shielding property or a light absorbing property, such as a metal chromium thin film or a tungsten thin film. It is also possible to form the light shielding layer 5 with an organic material. The illustrated light shielding layer 5 has a large number of regions 5a for preventing light degradation or the like of the active element.

  The transparent electrode pattern 7 is an electrode for forming a vertical electric field in the display liquid crystal panel, and is formed of a transparent electrode material such as indium tin oxide (ITO), indium oxide, or indium zinc oxide (IZO). The transparent electrode pattern 7 is used as a common electrode (common electrode) in a display liquid crystal panel, and its shape in plan view is a quadrangle.

  The flattening film 8 is for flattening irregularities formed by the surface shape of the color filter array 3, for example, and any material may be used, preferably an epoxy / acrylic type, Examples thereof include acrylic materials, epoxy resins, polyamide resins, organic silanes, cardo resins, organic materials such as organosilicon polymers, and inorganic materials such as polysilazane. Specific examples of the material of the planarizing film 8 (planarizing film material) include, for example, JNP80 manufactured by JSR, which is an acrylic resin, VPA100 manufactured by Nippon Steel Chemical Co., which is a cardo resin, and Sumitomo Chemical, which is an organosilicon polymer. Examples thereof include a spin-on-glass Smica film for interlayer flattening film manufactured by KK and polysilazane manufactured by Clariant.

  Using this planarizing film material, the planarizing film 8 is formed on the transparent electrode pattern 7 by a coating means such as spin coating or various printing means.

  The arrangement position of the planarizing film 8 is not particularly limited as long as the surface of the alignment film 9 can be planarized, and may be between the color filter array 3 and the transparent electrode pattern 7. It is preferably between the pattern 7 and the alignment film 9.

  Further, the planarizing film 8 only needs to be formed at a position corresponding to a boundary between an inclined alignment regulating region described later and the alignment film 9 where the inclined alignment regulating region is not formed. Of course, for example, the transparent electrode pattern 7 may be formed so as to cover the transparent electrode pattern 7 on the front surface.

  The thickness of the planarizing film 8 is not particularly limited, but is preferably approximately 10 nm to 100 nm.

  The alignment film 9 is for controlling the alignment direction of the liquid crystal molecules in the display liquid crystal panel. Examples of the material of the alignment film 9 include a fluorine-based silicone resin for forming a hydrophobic film (for example, a water repellent film manufactured by Toshiba Silicone Co., Ltd.). Hydrophobic silicone resins for commercial use), polyimide resins for vertical alignment film formation (for example, SE-1211 and SE-7511L manufactured by Nissan Chemical Industries, Ltd.) and alkoxysilane compounds, etc. used. As the hydrophobic material, a hydrophobic polymer material having a long side chain is particularly preferable. Further, the thickness of the alignment film 9 can be appropriately selected within a range of approximately 10 nm to 1000 nm, but it is preferable that the alignment film 9 is thin in order to suppress the image sticking phenomenon. The alignment film 9 need not be rubbed.

  If necessary, a photocatalyst such as titanium oxide (anatase type) particles or zinc oxide particles having an average particle diameter of about 5 μm to 20 μm can be contained in the alignment film 9 in a proportion of 20 to 40% by weight.

  In the liquid crystal alignment substrate 10 of this embodiment, an inclined alignment regulating region for aligning the director of liquid crystal molecules with respect to the normal direction of the substrate is provided in each region corresponding to the pixel in the surface of the alignment film 9. Is formed. Hereinafter, this point will be described in detail with reference to FIGS. The director is a unit vector representing the average orientation direction of liquid crystal molecules.

  FIGS. 5 and 11 show the color filters 3R, 3G, and 3B constituting one picture element and the surrounding light shielding layers 5 in the tilted alignment regulation region formed on the surface of the alignment film. In the upper part, inclined orientation regulating regions 52 and 55 having specific shapes are shown.

  In the individual regions corresponding to the pixels in the surface of the alignment film 9, inclined alignment regulating regions 52 and 55 for aligning the directors of the liquid crystal molecules with respect to the normal direction of the substrate are formed. That is, the inclined alignment regulating regions 52 and 55 are formed in a part of the alignment film 9, and the alignment film 9 (remaining alignment film) in which the inclined alignment regulating regions 52 and 55 are not formed is the hydrophobic regions 53 and 56. Formed as.

  The tilt alignment regulating regions 52 and 55 may be configured in any way as long as the director of liquid crystal molecules can be tilted and aligned with respect to the normal direction of the substrate. For example, the hydrophobic alignment film is made hydrophilic. This is a hydrophilic region having a side chain as shown in FIG. 7 obtained by processing. At this time, the critical surface free energy of the hydrophilic regions which are the tilted orientation regulating regions 52 and 55 is approximately 40 mN / m or more.

  By forming the tilt alignment regulating regions 52 and 55 in this way, the liquid crystal molecules on the tilt alignment regulating regions 52 and 55 are aligned with an inclination with respect to the normal direction of the substrate. When the voltage is applied to the liquid crystal molecules on the tilted alignment regulating regions 52 and 55, the liquid crystal molecules on the tilted regions 53 and 56 are further tilted earlier. Further, since the liquid crystal molecules on the tilted alignment regulating regions 52 and 55 are in close contact with the liquid crystal molecules of the hydrophobic regions 53 and 56, they may be aligned in parallel without being tilted with respect to the substrate normal direction. is there. In this case, when the power is turned on (when a voltage is applied between the substrates), the liquid crystal molecules on the tilt alignment regulation regions 52 and 55 are tilted earlier than the liquid crystal molecules on the hydrophobic regions 53 and 56. In particular, when the power is turned on, the liquid crystal molecules on the hydrophilic regions, which are the tilt alignment regulating regions 52 and 55, are quickly tilted and fall down. As a result, other liquid crystal molecules on the hydrophobic regions 53 and 56 are simultaneously tilted starting from the liquid crystal molecules on the tilt alignment regulating regions 52 and 55, so that the response time of the liquid crystal can be shortened.

  The shapes of the inclined orientation regulating regions 52 and 55 are not particularly limited. For example, they may be formed in a zigzag shape as shown in FIG. 5, or they are substantially isosceles triangles in plan view as shown in FIG. You may make it form in a shape etc. The boundaries (boundary lines) between the inclined orientation regulating regions 52 and 55 and the hydrophobic regions 53 and 56 are preferably formed linearly.

  As shown in FIG. 5, when the inclined alignment regulating region 52 is formed in a zigzag shape, the zigzag shape is not particularly limited, and may be a zigzag shape that bends randomly without a constant period or bending angle, but is preferable. Is preferably a zigzag shape with a constant bending angle and substantially the same bending angle.

  The angle θ (see FIG. 8) of the zigzag bent portion of the tilt alignment regulating region 52 is arbitrarily determined according to the type of liquid crystal molecules, the alignment pattern, the polarizing plate, and the like, but is preferably 90 °, for example. .

  The length between the zigzag bent portions (interval between adjacent bent portions) W3 (see FIG. 8) of the inclined orientation regulating region 52 is usually preferably 200 μm to 400 μm, particularly preferably 290 μm to 310 μm. is there. The length W4 (see FIG. 8) of the zigzag-shaped bending unit of the tilt orientation regulating region 52 is usually preferably 50 μm to 150 μm, and particularly preferably 90 μm to 110 μm.

  It is preferable that a plurality of the inclined orientation regulating regions 52 are formed at a predetermined interval. That is, it is preferable that the inclined orientation regulating regions 52 and the hydrophobic regions 53 are alternately arranged.

  The width W1 (see FIG. 8) of the tilt alignment regulating region 52 is usually arbitrarily determined according to the type of liquid crystal molecules, the alignment pattern, the polarizing plate, etc., but for example, 10 μm to 30 μm from the viewpoint of easy alignment. It is preferable that The interval (width of the hydrophobic region 53) W2 (see FIG. 8) of the inclined alignment regulating region 52 is usually arbitrarily determined according to the type of liquid crystal molecules, the alignment pattern, the polarizing plate, and the like. It is preferable that it is 20 micrometers-90 micrometers from a viewpoint of ease. Such a range is preferable because when the inclined alignment regulating region 52 is too narrow, the orientation of the liquid crystal molecules tends to be poor, and when it is too wide, the liquid crystal molecules tend not to be aligned perpendicular to the substrate. Because it becomes.

  In this way, by forming the tilted alignment regulating region 52 in a zigzag shape, the liquid crystal molecules on the tilted orientation regulating region 52 are tilted before the liquid crystal molecules on the hydrophobic region 53 when the power is turned on. At this time, the liquid crystal molecules on the tilted alignment regulating region 52 are tilted along the boundary between the hydrophobic region 53 and the tilted orientation regulating region 52, and the hydrophobic region 53 starts from the liquid crystal molecules on the tilted orientation regulating region 52. Since the liquid crystal molecules in the upper hydrophobic region 53 are inclined, it is considered that the orientation is controlled in at least two directions along the two sides forming the zigzag (see FIG. 9).

  For example, it is preferable that the inclined orientation regulating region 52 is positioned so that one or two or more bent portions are positioned for each pixel. It is particularly preferable that the two inclined regions for controlling the alignment of the liquid crystal molecules on the hydrophobic region 53 by the inclined alignment regulating region 52 are arranged so as to have substantially the same ratio in one pixel region.

  As described above, one or two or more bent portions of the tilt alignment regulating region 52 are positioned corresponding to each pixel region, so that each pixel region aligns directors of liquid crystal molecules in at least two directions when the power is turned on. To control. Further, since the alignment states are continuous with each other, no disclination is formed between the alignment films (boundaries), and display quality does not deteriorate.

  When the inclined orientation regulating region 55 is formed in a substantially isosceles triangle shape in plan view as shown in FIG. 11, the substantially isosceles triangle shape is not particularly limited, but the portion corresponding to the apex angle of the isosceles triangle is , Sharper than the portion corresponding to the base angle. This portion corresponds to the sharp portion in the present invention.

  The inclined alignment regulation region 55 is formed with regularity on the individual color filters 3R, 3G, and 3B. For example, on the color filter 3R, a portion corresponding to the base of an isosceles triangle is hypothesized that a plurality of inclined orientation regulating regions 55 are arranged at both sides of each of the four virtual lines L1, L2, L3, and L4. Each inclined orientation regulation region 55 formed on the line side and corresponding to one imaginary line is arranged substantially symmetrically about the imaginary line as an axis of symmetry. The virtual line L2 is parallel to the virtual line L1, and the virtual line L4 is parallel to the virtual line L3. The virtual line L2 and the virtual line L3 are perpendicular to each other. The virtual lines L1 and L2 and the virtual lines L3 and L4 as a whole have one symmetry axis, that is, a symmetry axis Ax that passes through the center of the color filter 3R and crosses the color filter 3R. This regularity applies not only to the color filter 3R but also to the arrangement of the inclined orientation regulating regions 55 on all the color filters.

  Each tilt alignment regulating region 55 serves as a trigger for determining the tilt direction of liquid crystal molecules when halftone display is performed by the vertical alignment type liquid crystal display device manufactured using the liquid crystal alignment substrate 10 of the present embodiment. Is. If the size of each tilted orientation regulating region 55 is too small, it cannot function as the trigger.

  The size of the tilted orientation regulating region 55 that can serve as a trigger varies depending on the shape of the tilted orientation regulating region 55, the material of the hydrophobic region 56, and the like. When the shape of the inclined orientation regulating region 55 is a substantially isosceles triangle, the portion corresponding to the apex angle of the isosceles triangle is a sharp portion, and the width of the portion corresponding to the base of the isosceles triangle is 20 μm. It has been confirmed that the role as the trigger is sufficiently fulfilled. The width is considered to be selectable within a range of about 5 to 20 μm.

  When no voltage is applied to each pixel of the vertical alignment type liquid crystal display device, the liquid crystal molecules on the tilt alignment regulating region 55 try to align horizontally, and the hydrophobic region 56 (the surface of the alignment film around the hydrophilic region 55 is formed). The same applies to the following. However, the liquid crystal is an elastic body, and when orientation distortion occurs locally, it tries to correct the distortion and maintain stability.

  In consideration of this point, in order to obtain a liquid crystal display device having excellent display quality, the arrangement pitch of the hydrophilic regions 55 in the direction along the imaginary line L1, L2, L3, or L4 is set to approximately 100 of the above width. It is preferable to set it to -300%, and it is still more preferable to set it as about 100-250% in general. Further, it is preferable that the ratio of the total area of the hydrophilic region 55 to the surface (alignment surface) of the hydrophobic region 56 is approximately 50% or less on at least the color filters 3R, 3G, and 3B.

  As described above, each tilt alignment regulating region 55 determines the tilt direction of liquid crystal molecules when halftone display is performed by the vertical alignment type liquid crystal display device manufactured using the liquid crystal alignment substrate 10 of this embodiment. Since it plays the role of a trigger, the vertical alignment type liquid crystal display device is a multi-domain liquid crystal display device. The reason for this will be described with reference to FIGS.

  FIG. 12 schematically shows a state of alignment of liquid crystal molecules when a saturation voltage Vsat is applied to each pixel of the vertical alignment type liquid crystal display device. As shown in the figure, the liquid crystal molecules M1 on the tilted alignment regulating region 55 are roughly arranged from the sharp portion (the portion corresponding to the apex angle of the isosceles triangle) S to the wide portion (the base of the isosceles triangle) of the tilted orientation regulating region 55. Oriented in the direction toward the corresponding part). In addition, since the liquid crystal molecules M1 on the tilt alignment regulating region 55 are originally intended to be horizontally oriented, the liquid crystal molecules M1 start to be tilted before the liquid crystal molecules M2 on the hydrophobic region 56 with the application of voltage, and the tilt alignment regulating region 55 The deformation of the liquid crystal accompanying the tilted alignment of the upper liquid crystal molecules M1 also propagates to the liquid crystal on the hydrophobic region 56. For this reason, the liquid crystal molecules M2 on the hydrophobic region 56 are also aligned in substantially the same direction as the direction of the tilt alignment of the liquid crystal molecules M1 on the tilt alignment regulating region 55.

  Therefore, for example, the liquid crystal molecules M1 on each tilt alignment restriction region 55 corresponding to the virtual line L1 shown in FIG. 11 and the liquid crystal molecules M1 on each tilt alignment restriction region 55 corresponding to the virtual line L2 are displayed in halftone display. In some cases, the orientation is inclined as schematically shown in FIG. In addition, the liquid crystal molecules M1 on each tilt alignment restriction region 55 corresponding to the virtual line L1 shown in FIG. 11 and the liquid crystal molecules M1 on each tilt alignment restriction region 55 corresponding to the virtual line L2 are displayed in halftone display. As shown schematically in FIG. 13B, the tilt orientation is performed.

  As a result, in the pixel including the color filter 3R shown in FIG. 11, for example, the liquid crystal is aligned and divided into four domains during halftone display. Similarly, in the pixel including the color filter 3G and the pixel including the color filter 3B, the liquid crystal is aligned and divided into four domains at the time of halftone display. A vertical alignment type liquid crystal display device manufactured using the liquid crystal alignment substrate 10 of this embodiment is a multi-domain liquid crystal display device, and has a wide viewing angle.

  As described above, the liquid crystal alignment substrate 10 of this embodiment forms the alignment film 9 by a relatively simple method of forming a plurality of inclined alignment regulating regions 52 and 55 on the surface of the alignment film. , Easy to reduce manufacturing costs. Further, by appropriately selecting the shape, size, and arrangement of the tilt alignment regulating regions 52 and 55, the display contrast, response speed, and viewing angle characteristics of the liquid crystal display device manufactured using the liquid crystal alignment substrate 10 are selected. Can be controlled. Accordingly, it is possible to manufacture a multi-domain vertical alignment type liquid crystal display device having excellent display characteristics at low cost.

(Second form)
FIG. 14 schematically shows a cross-sectional structure of a liquid crystal alignment substrate according to the second embodiment of the present invention. In the illustrated liquid crystal alignment substrate 20, a plurality of columnar spacers 12 are formed on the transparent electrode pattern 7 in addition to the planarizing film 8 and the alignment film 9, and the surface of each of these columnar spacers 12 is covered with the control film 15. In that respect, it is structurally different from the liquid crystal alignment substrate 10 of the first embodiment.

  Since the other configuration of the liquid crystal alignment substrate 20 is the same as that of the liquid crystal alignment substrate 10, the members shown in FIG. 14 that are functionally common to the members shown in FIG. The same reference numerals as those used in the above description are attached, and the description thereof is omitted.

  Each of the columnar spacers 12 provided on the liquid crystal alignment substrate 20 is formed of, for example, an organic material such as a photosensitive resin, and is disposed so as to overlap the light shielding layer 5 when viewed in plan. . These spacers 12 serve to keep the cell gap constant when a liquid crystal cell for display is manufactured using the liquid crystal alignment substrate 12 and another liquid crystal alignment substrate. The total number of columnar spacers 12 can be appropriately selected within a range in which the cell gap can be kept constant over the entire liquid crystal cell for display, and is not necessarily provided between adjacent color filters. .

  The control film 15 is a film for aligning liquid crystal molecules along the surface of the spacer 12, and is formed of, for example, a hydrophilic material.

  The liquid crystal alignment substrate 20 having such a configuration is used as a substrate on the display surface side of a display liquid crystal panel in an active matrix drive type vertical alignment liquid crystal display device using negative liquid crystal. Since the liquid crystal alignment substrate 12 includes the planarization film 8 and the alignment film 9 already described, the same technical effects as those of the liquid crystal alignment substrate 10 of the first embodiment are achieved.

(Third form)
FIG. 15A schematically shows the planar arrangement of the constituent members in the liquid crystal alignment substrate of the third embodiment according to the present invention, and FIG. 15B shows the XI-XI line shown in FIG. A cross section is shown schematically.

  The illustrated liquid crystal alignment substrate 50 is used as a back side substrate of a display liquid crystal panel in an active matrix driving type vertical alignment liquid crystal display device using negative liquid crystal, and the liquid crystal alignment substrate 50 is: The light-transmitting substrate 31, the transparent electrode pattern 33, the scanning line 35, the signal line 37, the switching circuit unit 39, the planarization film 42, and the alignment film 43 are included.

  A transparent electrode pattern 33, a scanning line 35, a signal line 37, and a switching circuit unit 39 are formed on one surface of the translucent substrate 31, and a protective film (passivation film) 41 is formed so as to cover them, and the protective film A planarizing film 42 is formed so as to cover 41, and an alignment film 43 is formed so as to further cover the planarizing film 42. The scanning line 35 and the signal line 37 are electrically separated by the interlayer flattening film 32. The transparent electrode pattern 33 is formed on the interlayer planarizing film 32. In FIG. 15A, in order to make the arrangement of the transparent electrode pattern 33, the scanning line 35, the signal line 37, and the switching circuit unit 39 easy to understand, an interlayer planarizing film 32, a protective film 41, and a planarizing film 42 are provided. The orientation film 43 is not shown.

  The translucent substrate 31 is formed of, for example, glass or quartz, and the interlayer planarization film 32 is formed of, for example, an electrically insulating material such as silicon oxide.

  The transparent electrode pattern 33 is composed of a large number of pixel electrodes 33a arranged in a matrix, and the shape of each pixel electrode 33a in plan view is a polygon such as a quadrangle or a pentagon. The illustrated pixel electrodes 33a each have a rectangular shape.

  The scanning lines 35 are arranged so as to correspond to one column of a large number of pixel electrodes 33a arranged in a matrix and extend in the longitudinal direction of the columns, and the signal lines 37 are arranged in a matrix. In addition, the pixel electrodes 33a are arranged so as to correspond to each row, and extend in the longitudinal direction of the row. These scanning lines 35 and signal lines 37 are formed of a metal such as tantalum (Ta) or titanium (Ti). Each scanning line 35 is formed on the surface of the translucent substrate 31 and covered with the interlayer planarizing film 32.

  The switching circuit unit 39 is arranged corresponding to one pixel electrode 33a one by one, the pixel electrode 33a corresponding to the switching circuit unit 39, the scanning line 35 corresponding to the pixel electrode 33a, and The signal line 37 is electrically connected. In response to the supply of a signal from the scanning line 35, the conduction between the signal line 37 and the pixel electrode 33a is controlled. Each switching circuit unit 39 is 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 protective film 41 is formed of, for example, silicon nitride and protects the underlying member.

  The flattening film 42 is formed by, for example, the above-described flattening film material and is used for flattening.

  The alignment film 43 is formed in the same manner as the alignment film 9 in the liquid crystal alignment substrate 10 of the first form.

  Since the liquid crystal alignment substrate 50 having the above-described configuration includes the alignment film 43 and the planarizing film 42, the same technical effect as the liquid crystal alignment substrate 10 of the first embodiment is obtained.

(Other forms)
The liquid crystal alignment substrate of the present invention has the greatest feature of forming an alignment film and a flattening film, and other configurations are used as, for example, a display surface side substrate of a display liquid crystal panel. Depending on whether it is used as a back side substrate, or depending on the driving method and display mode of the liquid crystal display device to be obtained (whether it is monochrome display, monocolor display, multicolor display or full color display), etc. It can be changed as appropriate.

  Further, the arrangement pattern of the hydrophilic regions in the alignment film can be appropriately selected according to the number of domains per pixel in the liquid crystal display device to be obtained, the shape of the pixel in plan view, and the like.

  For example, as shown in FIG. 10, the inclined orientation regulating region 52 may be formed by combining two of a zigzag shape and a triangular shape. That is, the inclined orientation regulating region 52 may be formed in a zigzag shape, and the zigzag bent portions may be formed so as to be connected to each other by triangular tips (sharp portions) 58 and 58. The bent portions (bent portions formed so as to be connected to each other at the sharp portions) may be formed in all the bent portions, or may be formed in every other bent portion. When forming in every other bending part, it is preferable to form in the position different from the bending part of the adjacent inclination orientation control area | region 52. FIG. In this way, by forming the bent portions so as to be connected to each other by the sharp portions 58 and 58, since the sharp portions 58 are inclined as starting points when the voltage is turned on, it responds quickly to the voltage.

  Further, when the shape of each pixel in the liquid crystal display device to be obtained is a square or a shape close to a square, each pixel has the same shape as the inclined alignment regulation region 55 shown in FIG. It is also possible to arrange four or eight inclined orientation regulation regions having a shape radially.

  In this case, it is possible to form more domains by increasing the number of inclined alignment regulating regions arranged radially, but the larger the number of domains, the better. In relation to the polarization direction of the polarizing plate, there arises a problem that the light use efficiency is lowered when the orientation of the tilted orientation of the liquid crystal molecules overlaps the respective orientations of the transmission axis and the absorption axis of the polarizing plate.

  In order to increase the light utilization efficiency, regardless of the arrangement pattern of the tilt alignment regulating region, the tilt alignment of the liquid crystal molecules should be controlled so as not to overlap the transmission axis and absorption axis of the polarizing plate. The main azimuth is preferably 4 or less in one pixel, and in the case of 4 azimuths, it is preferable that these azimuths are different by 90 °.

  The shape of each inclined alignment regulating region formed in the alignment film in a plan view may be a shape having at least one sharp part, for example, a rhombus shape having a pair of sharp parts, It can also be a fan shape having two sharp points. If there are too many sharp portions in one inclined alignment regulating region, it becomes difficult to define the alignment direction of the liquid crystal molecules by the inclined alignment regulating region. Therefore, the number of sharp portions in one inclined alignment regulating region is It is preferable to use one or two.

2. Method for Producing Liquid Crystal Alignment Substrate The method for producing a liquid crystal alignment substrate of the present invention is a liquid crystal alignment substrate used for a display liquid crystal panel of a multi-domain liquid crystal display device, particularly for the liquid crystal alignment of the present invention described above. This method is suitable as a method for manufacturing a substrate, and includes the following four steps.

  The first is a step of preparing a translucent substrate having at least a transparent electrode pattern formed on one side (hereinafter referred to as “preparation step”). The second is a step of forming a flattening film so as to cover the transparent electrode pattern (hereinafter referred to as “flattening film forming step”). The third is a step of forming an alignment film on the planarizing film (hereinafter referred to as “alignment film forming step”). Fourth, the surface of the alignment film is selectively hydrophilized, and the directors of the liquid crystal molecules are placed in the individual regions corresponding to the pixels in the surface of the alignment film with respect to the normal direction of the substrate. This is a step of forming an inclined alignment regulating region that is inclined and oriented (hereinafter referred to as “hydrophilization treatment step”). Hereinafter, these steps will be sequentially described.

(Preparation process)
The translucent substrate prepared in this step has the transparent electrode pattern formed thereon, and has a structure that can be used as it is as one of a pair of translucent substrates in a display liquid crystal panel.

  The structure of the translucent substrate is determined depending on, for example, whether it is used as a display surface side substrate or a back side substrate of a display liquid crystal panel, or a liquid crystal display device to be obtained Can be selected as appropriate according to the driving method and display mode (whether monochrome display, mono-color display, multi-color display or full-color display), and the manufacturing method thereof is not particularly limited.

  The above-mentioned translucent substrate may be produced by itself or may be purchased if there is a commercial product.

(Planarization film formation process)
As a constituent material of the planarizing film, for example, epoxy / acrylic, acrylic, epoxy-based, polyamide-based resins, organic silane, cardo-based resins, organic materials such as organosilicon polymers, inorganic materials such as polysilazane, etc. Can be mentioned. Using this planarizing film material, a planarizing film is formed on the transparent electrode pattern of the substrate by a coating means such as spin coating or various printing means.

(Alignment film formation process)
As a constituent material of the alignment film, for example, a fluorine-based silicone resin for forming a hydrophobic film (for example, a commercial product of a fluorine-based silicone resin for water repellent film manufactured by Toshiba Silicone), a polyimide resin for forming a vertical alignment film (for example, Nissan) Examples include SE-1211, SE-7511L) and alkoxysilane compounds that can be hydrophilized, and the like. Using this alignment film material, an alignment film is formed on the planarization film by a coating means such as spin coating or various printing means so as to cover the planarization film.

  However, the alignment film must be capable of hydrophilizing the surface, and as the alignment film material, the liquid crystal alignment substrate 10 of the first form according to the liquid crystal alignment substrate of the present invention described above ( The same materials as the alignment film material in FIGS. 4A and 4B) are exemplified. The film thickness is selected based on the same standard as the film thickness of the alignment film 9.

(Hydrophilic treatment process)
As a method for selectively applying a hydrophilic treatment to the surface of the alignment film, for example, the following three methods can be mentioned.

<Method I>
When the alignment film does not contain a photocatalyst, as shown in FIG. 16A, a translucent substrate 100 and a mask pattern 102 formed on one surface of the translucent substrate 100, In addition, a photomask (ultraviolet mask) 110 having a photocatalyst layer 104 covering the mask pattern 102 is used, and an ultraviolet light UV1 having a wavelength of 380 nm or less is maintained while keeping the distance between the photocatalyst layer 104 and the alignment film 140 at about 5 to 20 μm. Then, the alignment film 140 is exposed.

<Method II>
When the alignment film contains a photocatalyst, as shown in FIG. 16B, a translucent substrate 120 and a mask pattern 122 formed on one side of the translucent substrate 120, The alignment film 145 is irradiated with ultraviolet light UV1 having a wavelength of 380 nm or less while keeping the distance between the photomask 130 and the alignment film 145 containing the photocatalyst at about 5 to 20 μm. To expose.

<Method III>
As shown in FIG. 16C, a photomask (ultraviolet mask) 135 having the same structure as that of the photomask 130 is used, and the distance between the photomask 135 and the alignment film 140 is maintained at about 5 to 20 μm. The alignment film 140 is exposed with ultraviolet light UV2 having a wavelength of 200 nm or less.

  In any of these methods I to III, as the mask patterns 102 and 122, a plurality of openings are formed corresponding to the shape and arrangement pattern of the hydrophilic regions to be formed on the surfaces of the alignment films 140 and 145. Use what has been done.

  For example, when the alignment film 9 in which the hydrophilic regions 52 and 55 are formed with the arrangement pattern shown in FIG. 5 or FIG. 11 is obtained, the photomasks 150 and 160 shown in FIG. In addition, openings 152 and 162 having the same shape and size (line width W1, pitch L1) as the hydrophilic regions 52 and 55 are formed under the same pattern as the arrangement pattern of the hydrophilic regions 52 and 55. Use the mask pattern. The mask patterns 102 and 122 can be produced, for example, by patterning a chromium thin film into a predetermined shape.

  As the photocatalyst layer 104 used in the method I, for example, a photocatalyst such as titanium oxide (anatase type) particles or zinc oxide particles having an average particle diameter of about 5 to 20 μm is contained in a binder resin (for example, a silicone resin). Those contained in a proportion of ˜40% by weight are used. The film thickness of the photocatalyst layer 104 is preferably approximately in the range of 0.05 to 0.5 μm.

  In any method, the exposed region of the surfaces of the alignment films 140 and 145 is oxidized and reduced, and the region is changed to a hydrophilic region. The above-mentioned oxidation-reduction is considered to occur by the following mechanism. The following description of the mechanism will be given by taking as an example the case where the exposure object is the alignment film 140 and the alignment film 140 is a silicone resin.

When the surface of the alignment film 140 is selectively exposed with ultraviolet light UV1, active oxygen species (active oxygen O ₂ ^- or active hydroxyl group -OH) are generated between the photomask 110 and the alignment film 140, and this activity As shown in FIG. 19A, oxygen species or the like attack a side chain (for example, an alkyl side chain) on the surface of the alignment film 140 to cut the bond of the side chain. Then, as shown in FIG. 19B, the active oxygen species and the like are exchanged and bonded to the portion where the side chain is cut, and this is changed into a hydrophilic region.

  In the method I and the method II, the presence of the photocatalyst can generate active oxygen species and the like even by irradiation with ultraviolet light having a long wavelength.

  The exposure conditions in the hydrophilization treatment step are preferably selected so that a hydrophilic region having a critical surface free energy of approximately 40 mN / m or more can be obtained according to the presence or absence of a photocatalyst or the material of the hydrophobic alignment film. .

  A target liquid crystal alignment substrate can be obtained by the method including the preparation step, the planarization film formation step, the alignment film formation step, and the hydrophilic treatment step described above.

3. Liquid crystal display device (first form)
FIG. 17 is a partial cross-sectional view schematically showing a cross-sectional structure of the liquid crystal display device according to the first embodiment of the present invention. The illustrated liquid crystal display device 300 is a multi-domain vertical alignment liquid crystal display device including a display liquid crystal panel 200 and a backlight unit 250 installed on the back side of the display liquid crystal panel 200.

  The display liquid crystal panel 200 is a liquid crystal panel in which the liquid crystal alignment substrate 10 already described with reference to FIG. 4 or the like is used as a display surface side substrate, and the liquid crystal alignment substrate 50 already described with reference to FIG. . Of the members shown in FIG. 20, those already described are assigned the same reference numerals as those used in FIG. 4B or FIG.

  The liquid crystal alignment substrate 10 and the liquid crystal alignment substrate 50 are bonded to each other with a sealant (thermosetting resin) 205 in a state of being spaced apart from each other. The distance (cell gap) between the liquid crystal alignment substrates 10 and 50 is kept constant by the spherical spacers 210 dispersed in advance on the alignment film 43 of the liquid crystal alignment substrate 50, and there is no gap between them. Is filled with a liquid crystal 215 having negative dielectric anisotropy (negative liquid crystal; for example, MLC-6608, MLC-2037, MLC-2038, etc. manufactured by Merck).

  Further, a plate-shaped or film-shaped first polarizing element 220 is provided on the outer surface of the liquid crystal alignment substrate 10, and a plate-shaped or film-shaped second polarizer 220 is provided on the outer surface of the liquid crystal alignment substrate 50. The polarizing element 225 is provided. These polarizing elements 220 and 225 are in a relationship of orthogonal Nicols with each other.

  Since the liquid crystal display device 300 of the present embodiment having the above-described configuration includes the display liquid crystal panel 200 manufactured using the liquid crystal alignment substrates 10 and 50 of the present invention described above, display characteristics and response characteristics are improved. This is a liquid crystal display device that is easy to manufacture at a low cost.

  The arrangement pattern of the hydrophilic region in the alignment film 9 of the substrate for liquid crystal alignment 10 and the arrangement pattern of the hydrophilic region in the alignment film 43 of the substrate for liquid crystal alignment 50 can be matched in plan view.

(Second form)
FIG. 21 is a partial cross-sectional view schematically showing a cross-sectional structure of the liquid crystal display device according to the second embodiment of the present invention. The illustrated liquid crystal display device 500 is a multi-domain vertical alignment liquid crystal display device including a display liquid crystal panel 400 and a backlight unit 250 installed on the back side of the display liquid crystal panel 200.

  The liquid crystal display panel 400 is different from the liquid crystal display device 300 of the first embodiment in that the liquid crystal alignment substrate 20 already described with reference to FIG. 14 is used as the liquid crystal alignment substrate on the display surface side. Since the other configuration is the same as that of the liquid crystal display device 300, those already described among the members shown in FIG. 21 are denoted by the same reference numerals as those used in FIG. Is omitted.

  Like the liquid crystal display device 300 described above, the liquid crystal display device 500 having such a configuration is a liquid crystal display device that can be easily manufactured at a low cost with excellent display characteristics and response characteristics.

(Other forms)
In the liquid crystal display device of the present invention, at least one of the two liquid crystal alignment substrates constituting the display liquid crystal panel may be the liquid crystal alignment substrate of the present invention described above. Other configurations can be changed as appropriate according to the driving method and display mode of the liquid crystal display device (monochrome display, monocolor display, multicolor display, or full color display).

  Examples of the present invention will be described below.

(Example 1)
<Manufacture of liquid crystal alignment substrate>
First, a transparent substrate having a color filter array, a light shielding layer, and a transparent electrode pattern formed on one side is prepared. The shape of the color filter array, the light shielding layer and the transparent electrode pattern formed on the transparent glass substrate is the same as the color filter array 3 and the light shielding layer in the liquid crystal alignment substrate 10 shown in FIGS. 4 (a) and 4 (b). 5 and the shape of the transparent electrode pattern 7.

  On the transparent electrode pattern, an acrylic resin (manufactured by JSR, JNP80) was spin-coated to form a flattened film having a thickness of about 1 μm.

  On this flattening film, a hydrophobic resin composition (polyimide resin composition for vertical alignment, manufactured by Nissan Chemical Industries, SE-7511L) was spin-coated to form an alignment film.

  The surface of the alignment film at this time was measured using a stylus type surface shape measuring instrument; Dektek 8 (vertical resolution / measurement range: 10 A / 665 kA, measurement length: 200 μm) manufactured by ULVAC, Inc. And the difference in height was about 8 nm or less. The in-plane distance between the convex part and the concave part was about 200 μm. From this measurement result, the inclination angle of the surface of the alignment film with respect to the substrate (the angle with respect to the plane perpendicular to the normal direction of the substrate) is approximately 5 °. It was determined that the degree of tilting of the liquid crystal molecules in each tilted area was not disturbed. For this reason, after application of an electric field, alignment division along the shape of the hydrophilic / hydrophobic pattern was obtained without being affected by the steps and irregularities of the color filter substrate 1, and a viewing angle characteristic equivalent to that of MVA could be obtained.

  Next, the surface of the hydrophobic alignment film is selectively hydrophilized by the method I described above, and the hydrophilic film formed on the alignment film 9 of the liquid crystal alignment substrate 10 of the first form described above is formed on the surface. The hydrophilic region is formed in the same pattern as the arrangement pattern of the hydrophilic region 52. In the plan view, each hydrophilic region has a width W1 for forming the hydrophilic region shown in FIG. 5 of 20 μm, a length L1 to the bent portion of 60 mm, and an angle of the bent portion of 130 °.

In performing the hydrophilization treatment, a photocatalyst layer is formed using a silicone resin in which titanium oxide (anatase type) particles having an average particle diameter of 5 to 20 μm are dispersed at a ratio of 20 to 40% by weight, and the thickness (mask) The thickness at the opening of the pattern is 0.05 to 0.5 μm. Further, ultraviolet light (wavelength: 200 to 370 nm) of 10 mW / cm ² is irradiated for 60 to 180 seconds while keeping the distance between the photomask and the hydrophobic alignment film at about 20 μm.

  In this way, by selectively subjecting the surface of the hydrophobic alignment film to hydrophilic treatment, a liquid crystal alignment substrate (hereinafter referred to as “first liquid crystal alignment substrate”) having the same configuration as the liquid crystal alignment substrate 10 of the first embodiment described above. A liquid crystal alignment substrate ”).

<Manufacture of liquid crystal display devices>
First, separately from the first liquid crystal alignment substrate, a liquid crystal alignment substrate (hereinafter referred to as “a liquid crystal alignment substrate”) that can be used as a back side substrate (substrate on which an active element is formed) in an active matrix drive type display liquid crystal panel. A second liquid crystal alignment substrate ") is prepared.

  The second liquid crystal alignment substrate can constitute a vertical alignment type display liquid crystal panel together with the first liquid crystal alignment substrate, and a planarizing film is formed on the alignment film of the second liquid crystal alignment substrate. Is not formed. Except for the point that the planarizing film is not formed, the second liquid crystal alignment substrate has the same configuration as the liquid crystal alignment substrate 50 shown in FIGS.

Next, on the alignment film of the second liquid crystal alignment substrate, a spherical spacer (SP series) manufactured by Sekisui Fine Chemical Co., Ltd. is used 20 by using a spacer dry spray device (SDI-12 manufactured by ING Corporation). sprayed so that a density of 50 pieces / mm ^2.

  Next, a sealing material (XN-5A) manufactured by Mitsui Chemicals is applied to the edge (on the alignment film) of the second liquid crystal alignment substrate by a seal dispenser device, and the second liquid crystal alignment substrate and the first liquid crystal substrate described above. The liquid crystal alignment substrate is bonded so that the alignment film is on the inside.

  A pressure of about 20 kPa is applied to the two bonded liquid crystal alignment substrates using a press jig to bring the two liquid crystal alignment substrates into close contact with each other. In this state, the temperature is 180 ° C., the time is 60 minutes, and the cooling is performed. Heat treatment is performed under a condition for about 30 minutes to obtain an empty cell having a gap between substrates of about 4.5 μm.

  A negative type liquid crystal (MLC-6608) manufactured by Merck Co., Ltd. is injected into the empty cell using a vacuum injection device, the injection port is sealed, and a display liquid crystal panel is obtained.

  Thereafter, a backlight unit is installed on the back side of the second liquid crystal alignment substrate to obtain a multi-domain vertical alignment liquid crystal display device. This liquid crystal display device has the same configuration as the liquid crystal display device 300 shown in FIG. 20 except that the hydrophilic region is not formed in the alignment film of the second liquid crystal alignment substrate.

  In this liquid crystal display device, a good image display can be performed for any of black display, halftone display, and white display. Further, the viewing angle is sufficiently wide and uniform in all directions.

(Example 2)
<Manufacture of liquid crystal alignment substrate>
First, as a resin composition having the same configuration as that of the first liquid crystal alignment substrate in Example 1 and forming a hydrophobic alignment film, a water-repellent fluorosilicone resin (manufactured by Toshiba Silicone, TSL8233 and TSL8114). The liquid crystal alignment substrate having the same configuration as the liquid crystal alignment substrate 10 of the first embodiment described above (hereinafter referred to as “third liquid crystal alignment substrate”) in the same manner except that the alignment film is formed by using (). Manufactured.

<Manufacture of liquid crystal display devices>
A multi-domain vertical alignment type liquid crystal display device is obtained in the same manner as in Example 1 except that the third liquid crystal alignment substrate is used as the liquid crystal alignment substrate constituting the display liquid crystal panel. This liquid crystal display device has the same configuration as the liquid crystal display device 300 shown in FIG.

  In this liquid crystal display device, a good image display can be performed for any of black display, halftone display, and white display. Further, the viewing angle is sufficiently wide and uniform in all directions.

It is the schematic which showed an example of the liquid crystal cell. It is a figure which shows the relationship between a pretilt angle and light leakage. It is a figure which shows the relationship between a pretilt angle and a maximum contrast ratio. (A) is the schematic of the planar arrangement | positioning of the structural member in the liquid crystal aligning substrate of the 1st form which concerns on this invention, (b) is the schematic of the II cross section shown to (a). It is a top view which shows the 1st shape of the alignment film formed in the liquid crystal aligning substrate of this invention. It is a figure which shows an example of the hydrophobic alignment film surface of this invention. It is a figure which shows an example of the hydrophilic alignment film surface of this invention. It is a figure which shows an example of the inclination orientation control area | region of this invention. It is explanatory drawing which shows the mode of the liquid crystal molecule on the liquid crystal aligning substrate of this invention when a voltage is applied. It is a figure which shows the modification of the 1st shape of the orientation film | membrane formed in the liquid crystal aligning substrate of this invention, Comprising: It is explanatory drawing which shows the mode of the liquid crystal molecule when a voltage is applied. It is a top view which shows the 2nd shape of the alignment film formed in the liquid crystal aligning substrate of this invention. It is principal part explanatory drawing which shows the mode of the liquid crystal molecule on the liquid crystal aligning substrate of this invention shown in FIG. 8 when a voltage is applied. (A) is a figure when the state of the liquid crystal molecules on the liquid crystal alignment substrate of the present invention shown in FIG. 8 is displayed from a certain direction when halftone display is performed, and (b) is the state of the liquid crystal molecules in (a). It is a figure when seeing from the other direction. It is sectional drawing which shows roughly the board | substrate for liquid crystal aligning of the 2nd form which concerns on this invention. (A) is the schematic which shows the planar arrangement | positioning of the structural member in the liquid crystal aligning substrate of the 3rd form which concerns on this invention, (b) is the schematic of the XI-XI line cross section shown to (a). (A) is sectional drawing which shows roughly an example of the exposure process performed when manufacturing the liquid crystal aligning substrate by the manufacturing method of the liquid crystal aligning substrate of this invention, (b) is another thing of the said exposure process. It is sectional drawing which shows an example schematically, (c) is sectional drawing which shows schematically the further another example of the said exposure process. It is a top view of the exposure mask pattern of a board | substrate. It is a top view of the exposure mask pattern of a board | substrate. (A) is a schematic diagram showing how active oxygen species cut the side chains on the alignment film surface during the exposure process performed when the liquid crystal alignment substrate is manufactured by the method for manufacturing a liquid crystal alignment substrate of the present invention; (B) is a schematic diagram which shows a mode that the surface of alignment film selectively changed to the hydrophilic area | region by the said exposure process. 1 is a partial cross-sectional view schematically showing a liquid crystal display device according to a first embodiment of the present invention. It is a fragmentary sectional view which shows schematically the liquid crystal display device of the 2nd form which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 7 Transparent electrode pattern 8 Flattening film 9 Alignment film 10 Substrate for liquid crystal alignment 20 Substrate for liquid crystal alignment 31 Transparent substrate 33 Transparent electrode pattern 42 Flattening film 43 Alignment film 50 Substrate for liquid crystal alignment 52 Inclination alignment regulation area 53 Vertical Alignment regulation region 55 Tilt alignment regulation region 56 Vertical alignment regulation region 104 Photocatalyst layer 110 Photomask 130 Photomask 135 Photomask 140 Alignment film 200 Liquid crystal panel for display 300 Liquid crystal display device 400 Liquid crystal panel for display 500 Liquid crystal display device

Claims (9)

  An alignment film for aligning liquid crystal molecule directors along the substrate normal direction is formed on one surface of the substrate, and the liquid crystal molecule directors are aligned in the substrate normal direction within individual regions corresponding to the pixels in the alignment film. An alignment layer in which an inclined alignment regulating region is formed to be inclined with respect to the substrate, and at least the inclined alignment regulating region of the inclined alignment regulating region is not formed between the substrate and the alignment film; A liquid crystal alignment substrate, wherein a planarizing film is formed at a position corresponding to the boundary of the liquid crystal.   The liquid crystal alignment substrate according to claim 1, wherein the planarizing film is formed on an electrode formed on one surface of the substrate.   The liquid crystal alignment substrate according to claim 1, wherein the alignment film is a hydrophobic region, and the inclined alignment regulating region is a hydrophilic region. A method for producing a liquid crystal alignment substrate used in a display liquid crystal panel of a multi-domain liquid crystal display device,
Preparing a substrate having an electrode formed on one side;
Forming a planarization film on the electrode;
Forming an alignment film on the planarizing film;
The surface of the alignment film is selectively hydrophilized, and the directors of the liquid crystal molecules are inclined with respect to the normal direction of the substrate in individual regions corresponding to the pixels in the surface of the alignment film. Forming an inclined orientation regulating region to be caused;
A method for producing a substrate for aligning liquid crystal, comprising:   The method for producing a liquid crystal alignment substrate according to claim 4, wherein the hydrophilization treatment is performed by an exposure treatment using a mask having a photocatalyst layer.   The method for producing a liquid crystal alignment substrate according to claim 4, wherein the alignment film contains a photocatalyst. In a multi-domain liquid crystal display device,
An alignment film for aligning a director of liquid crystal molecules along the normal direction of the substrate is formed on one surface of one or both of the two substrates constituting the display liquid crystal panel. In each region corresponding to a pixel, an inclined alignment regulating region for aligning a director of liquid crystal molecules with an inclination with respect to a normal direction of the substrate is formed, and at least between the substrate and the alignment film, A liquid crystal display device, wherein a flattening film is formed at a position corresponding to a boundary between the inclined alignment regulating region and an alignment film in which the inclined alignment regulating region is not formed.   The liquid crystal display device according to claim 7, wherein the planarizing film is formed on an electrode formed on one surface of the substrate.   9. The liquid crystal display device according to claim 7, wherein the alignment film is a hydrophobic region, and the inclined alignment regulating region is a hydrophilic region.

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