JP2005107414A - Substrate for liquid crystal alignment, its manufacturing method, and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate for liquid crystal alignment capable of manufacturing a liquid crystal display of a multi-domain system having excellent display characteristics at low costs. <P>SOLUTION: The substrate for liquid crystal alignment used for a liquid crystal panel for display of the liquid crystal display of the multi-domain system is provided with at least a substrate 1, an electrode 7 formed on one surface of the substrate 1, an insulating layer 8 formed on the electrode 7 and an alignment layer 9 of a silane coupling agent formed on the insulating layer 8 and aligning directors of liquid crystal molecules along the normal direction of the substrate. Oblique alignment regulating regions aligning the directors of the liquid crystal molecules obliquely to the normal direction of the substrate are formed in individual regions corresponding to pixels in 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 type vertical alignment type liquid crystal display devices have been developed as liquid crystal display devices with small viewing angle dependence characteristics. It is put into practical use as a liquid crystal television.

  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 utilizing the birefringence of liquid crystal molecules, and it is easy to increase the display contrast and black level response compared to the TN type liquid crystal display device. Since it has an advantage that the speed can be easily increased, it is attracting more attention than an 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, Patent Document 1 discloses an opening at a predetermined position of a counter electrode, that is, a position facing a central portion of a pixel electrode. 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 inclined surface. Therefore, 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 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. An apparatus is described. In this vertical alignment type liquid crystal display device, similarly to the vertical alignment type liquid crystal display device described in Patent Document 2, a plurality of inclined surfaces having different inclination directions are aligned in each pixel region due to the presence of a structure. 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 at a predetermined position of the counter electrode, similarly to 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 when a voltage is applied.
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 to 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 the liquid crystal on the inclined surface is not applied when no voltage is applied. Since all of them are oriented along the inclined surface, there is a problem that a complete black display cannot be obtained and the contrast is lowered.

  Further, 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 aforementioned inclined surface steep, and for that purpose, Other problems also arise because it is necessary to thicken the structure. 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 aligned vertically when Δγ> 0, and are aligned horizontally 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 for a display liquid crystal panel of a multi-domain liquid crystal display device, and is formed on one side of the substrate. And an alignment layer of a silane coupling agent formed on the insulation layer and aligning a director of liquid crystal molecules along the normal direction of the substrate. In the alignment film, an inclined alignment regulating region is formed in each region corresponding to the pixel to align the director of the liquid crystal molecules with an inclination with respect to the normal direction of the substrate.

  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 between the alignment film and the tilt alignment regulating region, and the liquid crystal molecules on the alignment film are tilted starting from the liquid crystal molecules on the tilt alignment regulating region. . Therefore, the response when the voltage is on can be made faster. However, since the alignment film of the silane coupling agent, which has high adhesion and water repellency to the substrate and is easily available, is close to a single layer film, two substrates are present when foreign matter or the like is mixed in the liquid crystal panel. It is conceivable that a short circuit occurs and a voltage is not normally applied to cause a display defect. However, since an insulating film is provided in the present invention, two substrates are short-circuited even if foreign matter is mixed in the liquid crystal cell. There is nothing. In addition, since the alignment film in which the inclined alignment regulating region is formed can be obtained by subjecting the surface of the alignment film of the silane coupling agent to a hydrophilic treatment, it can be manufactured relatively easily at a low cost. it can. 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, (a) the inclined alignment regulating region is formed in a regular zigzag shape having the same period and the same width, and (b) each of the alignment films corresponding to a pixel. (C) at least one zigzag bent portion of the tilt orientation regulating region is disposed in the region, (c) a plurality of the tilt orientation regulating regions are formed at a predetermined interval, d) The inclined alignment regulation region has a shape having at least one sharp portion in plan view, and a plurality of the alignment regions are regularly formed in individual regions corresponding to pixels in the alignment film. (E) the shape of the inclined orientation regulating region in plan view is a substantially isosceles triangle, and the location corresponding to the apex angle of the isosceles triangle is more than the location corresponding to the base angle of the isosceles triangle (F) the alignment film; A hydrophobic region, said tilt regulating region is hydrophilic regions, is preferred. Here, the “pointed portion” in the present specification means a tip portion of a region having a spread angle of less than 60 °.

  The liquid crystal alignment substrate of the present invention that achieves the second object is a method for manufacturing a liquid crystal alignment substrate used in a display liquid crystal panel of a multi-domain liquid crystal display device, wherein an electrode is formed on one side. A step of preparing an insulating substrate, a step of forming an insulating layer on the electrode, a step of forming an alignment film of a silane coupling agent on the insulating layer, 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 this invention, the present invention is achieved by a relatively easy method in which an alignment film of a silane coupling agent is formed on an electrode via an insulating layer, and the surface of the alignment film is selectively subjected to a hydrophilic treatment. A liquid crystal alignment 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 type liquid crystal display device, and an electrode is formed on one surface of one or both of two substrates constituting a display liquid crystal panel. Forming an insulating layer on the electrode, and forming an alignment film of a silane coupling agent for aligning a director of liquid crystal molecules along the substrate normal direction on the insulating layer, Thus, a tilt alignment regulating region is formed in each region corresponding to a pixel, in which the director of liquid crystal molecules is tilted with respect to the normal direction of the substrate.

  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 in which two substrates are not short-circuited by an extremely easy process and at low cost.

  In the liquid crystal display device of the present invention, (i) the inclined alignment regulating region is formed in a regular zigzag shape having the same period and the same width, and (ii) each of the alignment films corresponding to a pixel. At least one zigzag bent portion of the tilt orientation regulating region is disposed in the region, (iii) a plurality of the tilt orientation regulating regions are formed at a predetermined interval, iv) The inclined alignment regulating region has a shape having at least one sharp portion in plan view, and a plurality of the alignment regions are regularly formed in each of the alignment films corresponding to pixels. (V) the shape in plan view of the inclined orientation regulating region is a substantially isosceles triangle, and the location corresponding to the apex angle of the isosceles triangle is more than the location corresponding to the base angle of the isosceles triangle (Vi) the alignment film is sparse A sex region, said tilt regulating region is hydrophilic regions, is preferred.

  As described above, according to the liquid crystal alignment substrate of the present invention, since the alignment film of the silane coupling agent is close to a single layer film, when foreign matter or the like is mixed in the liquid crystal panel, the two substrates are short-circuited. In the present invention, an insulating film is formed on the electrode, and an alignment film of the silane coupling agent is formed on the insulating film. Even if foreign matter is mixed in the two substrates, the two substrates are not short-circuited. In addition, since the alignment film in which the tilted alignment regulating region is formed can be obtained by subjecting the surface of the alignment film formed by the silane coupling agent to a hydrophilic treatment, it is relatively easy to manufacture at a low cost. can do. 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 display liquid crystal panel is formed using the above-described liquid crystal alignment substrate of the present invention, the liquid crystal display device in which the two substrates are not short-circuited is extremely easy. It can be manufactured by a 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 film of a silane coupling agent is formed, and a director of liquid crystal molecules is arranged in a part of each surface of the alignment film corresponding to a pixel with respect to the normal direction of the substrate. An inclined alignment regulating region for inclining orientation is formed. The reason why the present invention is configured in this way is that a vertical alignment polyimide is generally used as a material of an alignment film of a VA liquid crystal display device, but a silane coupling agent, a surfactant, etc. Can also be used. Among them, the silane coupling agent is a material system in which many materials with high adhesion and water repellency can be obtained. That is, the alignment film of the silane coupling agent is arranged so that each liquid crystal molecule is stuck in the vertical groove by arranging an infinite number of side chains of the silane coupling agent in the normal direction of the substrate. Take a vertical alignment.

  Since the alignment film of the silane coupling agent does not have a function as an insulating film and is close to a single layer film, when a foreign substance or the like is mixed in the liquid crystal cell, the two substrates are short-circuited and a voltage is normally applied. However, in the present invention, by providing the insulating film, both the water repellency and the insulating property are compatible, and even if foreign matter or the like is mixed in the liquid crystal cell, the two substrates are short-circuited. Without this, a hydrophilic / hydrophobic pattern can be formed.

  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. 1 (a) schematically shows a planar arrangement of components in the liquid crystal alignment substrate of the first embodiment according to the present invention, and FIG. 1 (b) shows an II line shown in FIG. 1 (a). A cross section is shown schematically.

  The illustrated liquid crystal alignment substrate 10 is used as a substrate on the display surface side of a display liquid crystal panel in an active matrix vertical alignment type 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, an insulating film 8 and an alignment film 9.

  The color filter array 3 and the light shielding layer 5 are formed on one surface of the translucent substrate 1, the transparent electrode pattern 7 covers the transparent filter pattern 7, and the insulating film 8 covers the transparent electrode pattern 7. Further, an alignment film 9 is formed on each insulating film 8. In FIG. 1A, the transparent electrode pattern 7, the insulating film 8, and the alignment film 9 are not shown for easy understanding of the arrangement of the color filter array 3 and the light shielding layer 5.

  The translucent substrate 1 is made of, for example, glass or transparent plastic. 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 light shielding layer 5 has a large number of regions 5a for preventing light degradation and 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 insulating film 8 is for electrically insulating the transparent electrode pattern 7 and the alignment film 9, and any material can be used, and a polymer material is preferable. Examples of the polymer material include a polyimide resin for forming a vertical alignment film, a polyamide resin, polyvinyl alcohol, polyacrylonitrile, nylon 6, 6 and the like, and a polyimide resin for forming a vertical alignment film is preferable. Examples of the polyimide resin for forming the vertical alignment film include commercially available photosensitive resins such as SE-1211 and SE-7511L manufactured by Nissan Chemical, which are polyimide resins for vertical alignment.

The alignment film 9 is for controlling the alignment direction of the liquid crystal molecules in the display liquid crystal panel. As a material for the alignment film 9, a silane coupling agent is used. As shown in FIG. 3, the surface can be subjected to a hydrophilic treatment, and a silane coupling agent having a long side chain is particularly preferable. Examples of the silane coupling agent include CH ₃ (CH ₂ ) ₇ Si (OCH ₃ ) ₃ ), CH ₃ (CH ₂ ) ₉ Si (OCH ₃ ) ₃ ), CH ₃ (CH ₂ ) ₁₁ Si (OCH ₃ ). ₃ ), CH ₃ (CH ₂ ) ₁₇ Si (OCH ₃ ) ₃ ) and the like. Specific examples include commercially available products of Toshiba Silicone's fluorine-based silicone resin for water-repellent films. Using these silane coupling agents, an alignment film 9 is formed on the insulating film 8 by a coating means such as spin coating or various printing means so as to cover the insulating film 8.

  Although the film thickness of the alignment film 9 is not specifically limited, For example, it is preferable that it is 1-5 nm.

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

  A feature of the liquid crystal alignment substrate 10 of this embodiment is that the alignment of the liquid crystal molecules is inclined with respect to the normal direction of the substrate in individual regions corresponding to the pixels on the surface of the alignment film 9. The area 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. 2 and 8 show the color filters 3R, 3G, and 3B constituting one picture element and the surrounding light shielding layer 5 in the tilted alignment regulation region formed on the surface of the alignment film. In the upper part of FIG. 5, 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. These are hydrophilic regions having side chains as shown in FIG. 4 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, as shown in FIG. 2, they may be formed in a zigzag shape. Also, 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.

  When the inclined alignment regulating region 52 is formed in a zigzag shape as shown in FIG. 2, 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. 5) 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. 5) of the inclined orientation regulating region 52 is preferably 200 μm to 400 μm, and particularly preferably 290 μm to 310 μm. is there. The length W4 (see FIG. 5) of the zigzag-shaped bending unit of the inclined 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. 5) 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, and the like. 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. 5) between the inclined alignment regulating regions 52 is usually arbitrarily determined according to the type of liquid crystal molecules, the alignment pattern, the polarizing plate, etc. 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. 6).

  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 FIGS. 8 and 9, the substantially isosceles triangle shape is not particularly limited, but corresponds to the apex angle of the isosceles triangle. The portion to be sharpened 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 a vertical alignment type liquid crystal display device manufactured using the liquid crystal alignment substrate 10 of this embodiment. To fulfill. If the size of each inclined 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 it sufficiently fulfills the role as the trigger. 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 (alignment film surface around the hydrophilic region 55). The same applies hereinafter.) The liquid crystal molecules on the top try to align vertically. 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 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 the 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. Therefore, the vertical alignment liquid crystal display device is a multi-domain liquid crystal display device. The reason for this will be described with reference to FIGS.

  FIG. 9 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 FIG. 9, the liquid crystal molecules M <b> 1 on the tilt alignment regulating region 55 generally have a sharp portion (a portion corresponding to the apex angle of the isosceles triangle) S to a wide portion (isosceles triangle) of the tilt alignment regulating region 55. Oriented in the direction toward the bottom 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. 8 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 alignment 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. 8 and the liquid crystal molecules M1 on each tilt alignment restriction region 55 corresponding to the virtual line L2 are displayed in a halftone display. As shown schematically in FIG. 10B, the tilt orientation is performed.

  As a result, in the pixel including the color filter 3R shown in FIG. 8, 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 the present embodiment is formed using 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 film formed of the silane coupling agent. Therefore, the manufacturing cost can be easily reduced. 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, a multi-domain vertical alignment type liquid crystal display device having excellent display characteristics can be manufactured at low cost.

(Second form)
FIG. 11 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 insulating film 8 and the alignment film 9, and the surface of each of these columnar spacers 12 is covered with the control film 15. This is different in structure 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. 11 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 structure 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 20 includes the insulating film 8 and the alignment film 9 which have already been described, the same technical effect as the liquid crystal alignment substrate 10 of the first embodiment is achieved.

(Third form)
FIG. 12A 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. 12B 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 drive type vertical alignment type liquid crystal display device using negative liquid crystal, and the liquid crystal alignment substrate 50 is A transparent substrate 31, a transparent electrode pattern 33, a scanning line 35, a signal line 37, a switching circuit portion 39, an insulating film 42, and an alignment film 43.

  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 An insulating film 42 is formed so as to cover 41 (and the pixel electrode 33a), and an alignment film 43 is formed so as to further cover the insulating film 42. The scanning line 35 and the signal line 37 are electrically separated by the interlayer insulating film 32. The transparent electrode pattern 33 is formed on the interlayer insulating film 32. In FIG. 12A, 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, the interlayer insulating film 32, the protective film 41, the insulating film 42, and the orientation are arranged. The illustration of the film 43 is omitted.

  The translucent substrate 31 is made of, for example, glass or quartz, and the interlayer insulating film 32 is made 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 insulating 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 insulating film 42 is formed of, for example, a polyimide resin for forming a vertical alignment film, and electrically insulates the alignment film 43.

  The alignment film 43 is formed on the surface of a film formed of a silane coupling agent 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 insulating film 42, the same technical effect as the liquid crystal alignment substrate 10 of the first embodiment is achieved.

(Other forms)
The liquid crystal alignment substrate of the present invention has the greatest feature in the combination of the alignment film of the silane coupling agent and the insulating film, and the other configuration is, for example, as a display surface side substrate of a liquid crystal panel for display. Depending on whether it is used as a backside 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) And 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. 7, the inclined orientation regulation 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.

  In addition, 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, the inclined alignment regulation region 55 shown in FIGS. 8 and 9 is provided for each pixel. It is also possible to radially arrange four or eight inclined orientation regulating regions having the same shape as in FIG.

  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 an insulating film so as to cover the transparent electrode pattern (hereinafter referred to as “insulating film forming step”). The third is a step of forming an alignment film of a silane coupling agent on the insulating 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.

(Insulating film formation process)
Examples of the constituent material of the insulating film include a polyimide resin for forming a vertical alignment film. Using this insulating film material, an insulating film is formed on the transparent electrode pattern of the substrate by coating means such as spin coating and various printing means.

(Alignment film formation process)
Examples of the silane coupling agent include fluoroalkylsilanes C ₈ F ₁₇ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ , C ₈ F ₁₇ (CH ₂ ) ₉ Si (OCH ₃ ) _{3, and the} like. Using this silane coupling agent, an alignment film is formed on the insulating film by a coating means such as spin coating or various printing means so as to cover the insulating film.

  However, the alignment film must be capable of hydrophilizing the surface, and as the silane coupling agent, the liquid crystal alignment substrate 10 according to the first embodiment of the liquid crystal alignment substrate of the present invention described above. Examples are the same as the silane coupling agent in FIG. 1 (a) and FIG. 1 (b). The film thickness is selected based on the same standard as the film thickness of the alignment film 9.

(Hydrophilic treatment process)
Examples of the method for selectively subjecting the surface of the alignment film of the silane coupling agent to the hydrophilization treatment include the following three methods.

<Method I>
When the alignment film does not contain a photocatalyst, as shown in FIG. 13A, a translucent substrate 100 and a mask pattern 102 formed on one side 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 ultraviolet light UV1 having a wavelength of 380 nm or less is maintained while maintaining 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. 13B, 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. 13C, a photomask (ultraviolet mask) 135 having the same structure as that of the photomask 130 is used, and the interval 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. 2 or 8 is to be obtained, the photomasks 150 and 160 shown in FIG. 14 or 15 are used. 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. 16A, 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. 16B, 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 insulating 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. As shown in FIG. 17, the liquid crystal display device 300 includes a multi-domain vertical alignment type liquid crystal including a display liquid crystal panel 200 and a backlight unit 250 installed on the back side of the display liquid crystal panel 200. It is a display device.

  The display liquid crystal panel 200 is, for example, a liquid crystal panel in which the liquid crystal alignment substrate 10 already described with reference to FIG. 1 or the like is used as a display surface side substrate, and the liquid crystal alignment substrate 50 already described with reference to FIG. It is. Of the members shown in FIG. 17, those already described are assigned the same reference numerals as those used in FIG. 1 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. 18 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. As shown in FIG. 18, a liquid crystal display device 500 includes a multi-domain vertical alignment type liquid crystal including a display liquid crystal panel 400 and a backlight unit 250 installed on the back side of the display liquid crystal panel 200. It is a display device.

  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. 11 is used as the liquid crystal alignment substrate on the display surface side. Since the other configurations are the same as those of the liquid crystal display device 300, those already described among the members shown in FIG. 18 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. 1 (a) and 1 (b). 5 and the shape of the transparent electrode pattern 7.

  On the transparent electrode pattern, polyimide for horizontal alignment film (SE-7492 manufactured by Nissan Chemical Industries, Ltd.) is applied by flexographic printing, dried at 180 ° C. for 1 hour using a hot plate, and insulated with a thickness of 60 nm. A membrane (polymer membrane) was formed.

Next, 1.5 g of fluoroalkylsilane (C ₈ F ₁₇ (CH ₂ ) ₂ Si (OCH ₃ ) ₃ ), 5.0 g of tetramethoxysilane (Si (OCH ₃ ) ₄ ), HCl ((0.005 normal)) (26.6 wt%) 2.36 g was reacted by stirring at room temperature for about 20 hours (solution A).

  This solution A was spin-coated with a thickness of 0.01 to 1 μm on the insulating film and dried at 180 ° C. for 1 hour to form an alignment film.

  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. 2 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 an insulating film is provided on the alignment film of the second liquid crystal alignment substrate. Not formed. Except that the insulating film is not formed, the second liquid crystal alignment substrate has the same configuration as the liquid crystal alignment substrate 50 shown in FIGS. 12 (a) and 12 (b).

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.

  After that, a backlight unit is installed on the back side of the second liquid crystal alignment substrate to obtain a multi-domain vertical alignment type liquid crystal display device. This liquid crystal display device has the same configuration as the liquid crystal display device 300 shown in FIG. 17 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, the liquid crystal alignment substrate 10 of the first embodiment described above has the same configuration as that of the first liquid crystal alignment substrate in Example 1 except that an alignment film is formed using the following solution B. A liquid crystal alignment substrate (hereinafter referred to as “third liquid crystal alignment substrate”) having the same configuration as in FIG.

Solution B
Fluoroalkylsilane (C ₈ H ₁₇ (CH ₂ ) ₉ Si (OCH ₃ ) ₃ ) 5.0 g, tetramethoxysilane (Si (OCH ₃ ) ₄ ) 5.0 g, HCl ((0.005 normal) 26.6 wt %) 2.36 g was stirred and reacted at room temperature for about 20 hours to obtain a solution B.

  Further, the liquid crystal alignment substrate 50 of the second embodiment described above has the same configuration as that of the second liquid crystal alignment substrate in Example 1 except that an alignment film is formed using the solution B. A liquid crystal alignment substrate (hereinafter referred to as “fourth liquid crystal alignment substrate”) having the same configuration as in FIG.

<Manufacture of liquid crystal display devices>
A multi-domain vertical alignment type in the same manner as in Example 1 except that the third liquid crystal alignment substrate and the fourth liquid crystal alignment substrate are used as the liquid crystal alignment substrate constituting the liquid crystal panel for display. A liquid crystal display device is obtained. 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.

(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 Insulating film 9 Alignment film 10 Substrate for liquid crystal alignment 20 Substrate for liquid crystal alignment 31 Transparent substrate 33 Transparent electrode pattern 42 Insulating film 43 Alignment film 50 Substrate for liquid crystal alignment 52 Inclination alignment control area 53 Vertical alignment control Region 55 Inclination alignment restriction region 56 Vertical alignment restriction region 104 Photocatalyst layer 110 Photomask 130 Photomask 135 Photomask 140 Alignment film 200 Display liquid crystal panel 300 Liquid crystal display device 400 Display liquid crystal panel 500 Liquid crystal display device

Claims (17)

A liquid crystal alignment substrate used in a display liquid crystal panel of a multi-domain liquid crystal display device,
A substrate, an electrode formed on one side of the substrate, an insulating layer formed on the electrode, and a silane coupling formed on the insulating layer and aligning directors of liquid crystal molecules along the normal direction of the substrate An alignment film of an agent,
A tilt alignment regulating region for tilting a director of liquid crystal molecules with respect to the normal direction of the substrate is formed in each of the alignment films corresponding to the pixels. substrate.   The liquid crystal alignment substrate according to claim 1, wherein the inclined alignment regulating region is formed in a regular zigzag shape having the same period and the same width.   3. The liquid crystal alignment substrate according to claim 2, wherein at least one zigzag bent portion of the inclined alignment regulating region is disposed in each region corresponding to a pixel in the alignment film. .   4. The liquid crystal alignment substrate according to claim 1, wherein a plurality of the tilt alignment regulating regions are formed at a predetermined interval. 5.   The inclined alignment regulation region has a shape having at least one sharp portion in plan view, and a plurality of the inclined alignment restriction regions are regularly formed in each region corresponding to the pixel in the alignment film. The substrate for aligning liquid crystal according to claim 1.   The shape in plan view of the inclined orientation regulating region is a substantially isosceles triangle, and the location corresponding to the apex angle of the isosceles triangle is sharper than the location corresponding to the base angle of the isosceles triangle. The substrate for aligning liquid crystal according to claim 5.   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 an insulating layer on the electrode;
Forming an alignment film of a silane coupling agent on the insulating layer;
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 substrate for aligning liquid crystal according to claim 8, 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 8, wherein the alignment film contains a photocatalyst. A multi-domain liquid crystal display device,
An electrode is formed on one surface of one or both of two substrates constituting a display liquid crystal panel, an insulating layer is formed on the electrode, and a director of liquid crystal molecules is formed on the insulating layer by a substrate method. An alignment film of a silane coupling agent that is aligned along the line direction is formed, and the director of liquid crystal molecules is inclined with respect to the normal direction of the substrate in each region corresponding to the pixel in the alignment film. A liquid crystal display device characterized in that an inclined alignment regulating region is formed.   The liquid crystal display device according to claim 11, wherein the inclined alignment regulating region is formed in a regular zigzag shape having the same period and the same width.   13. The liquid crystal display device according to claim 12, wherein at least one zigzag bent portion of the inclined alignment regulation region is disposed in each region corresponding to a pixel in the alignment film.   14. The liquid crystal display device according to claim 11, wherein a plurality of the tilt alignment regulating regions are formed at a predetermined interval.   The inclined alignment regulation region has a shape having at least one sharp portion in plan view, and a plurality of the inclined alignment restriction regions are regularly formed in each region corresponding to the pixel in the alignment film. The liquid crystal display device according to claim 11.   The shape in plan view of the inclined orientation regulating region is a substantially isosceles triangle, and the location corresponding to the apex angle of the isosceles triangle is sharper than the location corresponding to the base angle of the isosceles triangle. The liquid crystal display device according to claim 15.   17. The liquid crystal display device according to claim 11, wherein the alignment film is a hydrophobic region, and the inclined alignment regulating region is a hydrophilic region.

Images