JP2004286993A - Liquid crystal display and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display having high response speed and a wide visual field angle and to provide a manufacturing method of the liquid crystal display effective in cost reduction. <P>SOLUTION: In the liquid crystal display of a vertical alignment system having first and second substrates and a liquid crystal interposed between the substrates, alignment layers arranging the directors of liquid crystal molecules along the normal direction of the substrates are formed on the first and the second substrates, respectively, at least one alignment layer of the alignment layers consists of a polymer film 5 having long side chains and high hydrophobicity and a slope region 6 having side chains shorter than the side chains of the polymer film 5 and sloping the directors of the liquid crystal molecules with respect to the normal direction of the substrates is formed at a part of the polymer film 5. The side chains of the polymer film 5 are represented by -(CH<SB>2</SB>)n-(CF<SB>2</SB>)m-CF<SB>3</SB>(wherein, n denotes an integer of 2 or more and m denotes an integer of 7 or more) or -(CH<SB>2</SB>)p-CH<SB>3</SB>(wherein, p denotes an integer of 7 or more) and the side chains of the slope region 6 are preferably -OH groups. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal display device and a method of manufacturing the same, and more particularly, to a liquid crystal display device that displays a television image, a computer image, or the like, has a high response speed and a wide viewing angle, and a method of manufacturing the same. is there.
[0002]
[Prior art]
Liquid crystal display devices are widely used as various display devices because they can be thinned and driven at low voltage. In particular, a TN type liquid crystal display device in which an active switch element such as a TFT (thin film transistor) is incorporated in each pixel exhibits a display performance comparable to that of a CRT, and is used for a display of a personal computer, a television, or the like. However, the TN type liquid crystal display device has a drawback that the response speed is slow and the viewing angle is narrow. Various researches and developments have been made to solve the drawbacks of the TN type liquid crystal display device, but on the other hand, a vertical alignment type liquid crystal display device in which directors of liquid crystal molecules are arranged in the normal direction of the substrate. Has also been researched and developed.
[0003]
The vertical alignment type liquid crystal display device has an advantage that the front contrast is excellent and the rubbing treatment is not required in the manufacturing process, and various research and development are being actively conducted. Also in this vertical alignment type liquid crystal display device, similarly to the above-mentioned TN type liquid crystal display device, there is a demand for improvement in viewing angle characteristics and improvement in response speed.
[0004]
In response to such demands, a technique for controlling the tilt direction of liquid crystal molecules to be plural in one pixel, that is, a multi-domain technique has been proposed. As a multi-domain technology, as shown in FIG. 10, it has been proposed to dispose a projecting structure 97 at an arbitrary position under the alignment film 96 (for example, see Non-Patent Document 1). According to this multi-domain technique, when the voltage is turned off, the liquid crystal molecules 94 slightly tilt along the slope of the structure 97, and when the voltage is turned on, the slightly tilted liquid crystal molecules 94 move along the tilt direction. And the liquid crystal molecules 95 other than the structure 97 also sequentially tilt in the same direction under the influence of the liquid crystal molecules 94. That is, the alignment of the liquid crystal molecules 94 and 95 is controlled with the structure 97 as a starting point.
[0005]
As for the alignment control of the liquid crystal molecules using the projection-like structure, the structure is provided two-dimensionally in a linear and rectangular shape to form a four-divided domain structure. There is known an example in which a domain structure in which liquid crystal molecules are tilted in all directions by being provided in a dot-like manner.
[0006]
On the other hand, for controlling the alignment of liquid crystal molecules regardless of the structure, for example, a method of alternately providing horizontal alignment regions and vertical alignment regions on a substrate (for example, see Patent Document 1), a thin film inclined in a certain direction A method of forming constituent molecules in one pixel (for example, see Patent Documents 2 and 3) and the like.
[0007]
[Non-patent document 1]
Fujitsu FIND, Vol. 19, no. 5, 2001 (FIGS. 1 to 3)
[Patent Document 1]
JP-A-10-206834 (FIGS. 1 and 5)
[Patent Document 2]
JP-A-11-167114 (FIGS. 5 and 12)
[Patent Document 3]
JP 2001-281669 A (FIGS. 4 to 7)
[0008]
[Problems to be solved by the invention]
However, in the above-described alignment control using the projection-like structure, a plurality of steps are required to form the structure, and there is a problem that the cost of the liquid crystal display device increases. Furthermore, the liquid crystal material used therein has a twist structure spontaneously in the cell gap, so that it must contain a large amount of chiral agent, and as a result, the response time tends to be prolonged.
[0009]
Further, in the above-described alignment control that does not depend on the structure, there is a problem that a partition is formed in a minute pixel, so that the manufacturing process is complicated and the response time is not sufficient.
[0010]
The present invention has been made in order to solve the above-described problems, and has as its object to provide a liquid crystal display device having a high response speed and a wide viewing angle, and to provide a method of manufacturing a liquid crystal display device which is effective for cost reduction. It is assumed that.
[0011]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a liquid crystal display device of a vertical alignment type including a first substrate, a second substrate, and a liquid crystal interposed between the substrates. On the substrate and the second substrate, alignment films for arranging directors of liquid crystal molecules in a direction normal to the substrate are formed, and at least one of the alignment films has a side chain length of at least one. A long hydrophobic polymer film, part of which has a shorter chain length than the side chain of the polymer film, and the side chain that tilts the director of liquid crystal molecules with respect to the normal direction of the substrate. Characterized in that an inclined region having the following is formed.
[0012]
According to the present invention, since the liquid crystal molecules on the inclined region are inclined with respect to the normal direction of the substrate, the liquid crystal molecules on the inclined region are easily inclined when the power is turned on. , The other liquid crystal molecules are simultaneously inclined. As a result, the response time of the liquid crystal can be shortened.
[0013]
According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, the inclined region is a hydrophilic region.
[0014]
According to the present invention, since the inclined region is a hydrophilic region, the liquid crystal molecules on the hydrophilic region are quickly inclined and fall when the power is turned on.
[0015]
According to a third aspect of the present invention, in the liquid crystal display device according to the first or second aspect, the polymer film is a hydrophobic film formed of a fluorine-based silicone resin or a polyimide resin, and the inclined region is formed of the fluorine-based film. It is a hydrophilic region in which a hydrophilic group is provided to a silicone film or a polyimide film.
[0016]
A fourth aspect of the present invention, in the liquid crystal display device according to any one of claims 1 to 3, the polymer _{membrane, - (CH 2) n- (} CF 2) m-CF 3 (n is 2 or more , And m represents an integer of 7 or more), and the side chain of the inclined region is an —OH group.
[0017]
A fifth aspect of the present invention, in the liquid crystal display device according to any one of claims 1 to 3, the side chain of the polymer _film, - a _{(CH 2) p-CH 3} (p is an integer of seven or more And the side chain of the inclined region is an —OH group.
[0018]
The invention according to claim 6 for solving the above problem has a first substrate, a second substrate, and a liquid crystal interposed between these substrates, and the first substrate and the second substrate include: Alignment films for arranging directors of liquid crystal molecules along the normal direction of the substrate are formed, and at least one of the alignment films is a hydrophobic polymer film having a long side chain. In a part of the polymer film, an inclined region having a shorter side chain than the side chain of the polymer film and having a side chain that inclines the director of the liquid crystal molecule with respect to the normal direction of the substrate is formed. A method for manufacturing a vertical alignment type liquid crystal display device, comprising: a hydrophobic substrate having a side chain whose side chain can be replaced and whose chain length is long on at least one of a first substrate and a second substrate. Forming a polymer film, and substituting a part of side chains of the polymer film Characterized in that it comprises a step of forming an inclined region Te.
[0019]
According to the present invention, by replacing some side chains of the polymer film, it is possible to form an inclined region in which the director of the liquid crystal molecules is inclined with respect to the normal direction of the substrate. Even if a thin film is not formed, it is possible to form an inclined region that enables control of liquid crystal alignment by an extremely easy process. As a result, the liquid crystal display device can be manufactured efficiently, which can contribute to cost reduction.
[0020]
According to a seventh aspect of the present invention, in the method for manufacturing a liquid crystal display device according to the sixth aspect, in the step of forming the inclined region, the substitution of the side chain of the polymer film is a hydrophilic treatment.
[0021]
According to the present invention, a hydrophilic region can be formed by a simple method of substituting a side chain of a polymer film and performing a hydrophilic treatment.
[0022]
According to an eighth aspect of the present invention, in the method for manufacturing a liquid crystal display device according to the seventh aspect, the hydrophilic treatment is performed by an exposure treatment using a mask having a photocatalyst layer.
[0023]
According to this invention, since the exposure is performed by using a mask having a photocatalyst layer, the hydrophobic film can be very easily changed to a hydrophilic film by the action of the photocatalyst at the time of exposure, and the exposure can be performed only by the exposure process. A surface whose orientation can be easily controlled can be formed.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a liquid crystal display device and a method of manufacturing the same according to the present invention will be described with reference to the drawings.
[0025]
(Liquid crystal display)
FIG. 1 is a schematic diagram showing changes in directors of liquid crystal molecules when a voltage is applied between substrates in a vertical alignment type liquid crystal display device. FIG. 1A shows a mode in which directors of the liquid crystal molecules 4 are arranged in the substrate normal direction Y when the power is turned off (V = 0), and FIG. FIG. 1 (c) shows a state when a critical voltage Vc at which the liquid crystal molecules 4 start to tilt is given, and FIG. 1 (c) shows a state when a saturation voltage Vsat at which the liquid crystal molecules 4 sufficiently tilt is applied. The director is a unit vector representing the average orientation direction of the liquid crystal molecules 4.
[0026]
As shown in FIG. 1, the liquid crystal display device of the present invention comprises a first substrate 1, a second substrate 2, and a liquid crystal having a negative dielectric anisotropy injected between the opposing substrates 1 and 2. 3) is a vertical alignment type liquid crystal display device.
[0027]
In this liquid crystal display device, alignment films 5 for aligning directors of liquid crystal molecules 4 in a direction normal to the substrate when power is turned off are provided on the surface of the first substrate 1 on the liquid crystal 3 side and the surface of the second substrate 2 on the liquid crystal 3 side. It is formed.
[0028]
At least one of the alignment films 5 (both in the example shown in FIG. 1) is a hydrophobic polymer film 5 having a long side chain as shown in FIG.
[0029]
The length and structure of the side chain of the polymer film 5 are not particularly limited as long as the side chain is long enough to show hydrophobicity because the chain length is long. . The side chain of the polymer film, specifically, for _{example, - (CH 2) n- (} CF 2) in m-CF _3, what n is representing an integer of 2 or more, m is an integer of seven or more, respectively, - in _{(CH 2) p-CH 3} , p is preferably such that an integer of 7 or more.
[0030]
The polymer film 5 is preferably a polymer film which is originally hydrophobic but can be made hydrophilic by performing a hydrophilic treatment. For example, the side chain for forming the hydrophobic film is-(CH ₂ ). _{n- (CF 2) m-CF} 3 (n is 2, m is 7) a is a fluorine-based silicone resin or side chain _{- (CH 2) n- (CF} 2) m-CF 3 (n is 2, m Is a polyimide resin for forming a vertical alignment film described in 7).
[0031]
As the fluorine-based silicone resin for forming a hydrophobic film, for example, commercially available photosensitive resins such as a fluorine-based silicone resin for forming a water-repellent film such as a product of Toshiba Silicone can be exemplified. Examples of the polyimide resin include JALS-688 manufactured by Nippon Synthetic Rubber, and SE-7511L and SE-1211 manufactured by Nissan Chemical Industries, which are polyimide resin compositions for vertical alignment. The thickness of the polymer film 5 is not particularly limited, but is preferably, for example, 10 nm to 100 nm.
[0032]
In the polymer film 5, an inclined region 6 having a shorter side chain than the side chain of the polymer film 5 and having a side chain for inclining the director of the liquid crystal molecule 4 with respect to the normal direction of the substrate is formed. .
[0033]
The inclined region 6 is preferably a hydrophilic region obtained by hydrophilizing the hydrophobic polymer film 5 from the viewpoint of making it easier to incline the director of the liquid crystal molecules 4 in a certain direction. .
[0034]
If the length of the side chain of the inclined region 6 is short so that the director of the liquid crystal molecule 4 can be inclined in a certain direction as compared with the director of the liquid crystal molecule 4 on the polymer film 5 when the power is turned on, Is not particularly limited. Specifically, the side chain of the inclined region 6 is preferably, for example, a hydrophilic group such as an —OH group (hydroxyl group), a sulfate group, a carboxyl group, or a sulfone group, and particularly preferably an —OH group. .
[0035]
As described above, since the liquid crystal molecules 4 on the inclined region 6 are inclined with respect to the normal direction of the substrate, when the power is turned on (when voltage is applied between the substrates), the liquid crystal molecules on the inclined region 6 It will easily tilt. In particular, when the inclined region 6 is a hydrophilic region, the hydrophilic region makes the liquid crystal molecules 4 substantially parallel to the normal direction of the substrate, so that when the power is turned on, the liquid crystal molecules 4 on the hydrophilic region are quickly inclined. And fall. As a result, the other liquid crystal molecules 4 are simultaneously inclined starting from the liquid crystal molecules 4 on the inclined region 6, so that the response time of the liquid crystal can be shortened.
[0036]
It is preferable that the shape of the inclined region 6 is designed so that the liquid crystal molecules 4 on the inclined region 6 are inclined in a predetermined direction when the power is turned on. Since the liquid crystal molecules 4 are easily inclined in a predetermined direction when the power is turned on by designing the inclined region 6 in such a manner, for example, a voltage at which the inclination starts to occur (also referred to as a critical voltage Vc) is smaller than in the past. This has the effect of shortening the time from when the liquid crystal molecules 4 on the tilted area 6 first tilt to when the entire liquid crystal molecules 4 tilt (also called response time).
[0037]
The shape of the inclined region 6 is not particularly limited as long as the shape produces the above-mentioned effect. For example, as shown in FIG. 3A, the liquid crystal molecules 4 fall toward the opposite side 13 when the power is turned on. It is preferable to use a triangle 11 having an acute angle portion 12 inclined as described above or a composite shape in which two or more triangles 11 are combined. In particular, when the triangular inclined region 6 as shown in FIG. 3A is formed, there is an effect that the response time of the liquid crystal alignment is shortened. The reason is that when the power is turned on, the liquid crystal molecules 4 near the acute angle portion 12 first begin to tilt toward the opposite side 13 of the acute angle portion 12, and then the other liquid crystal molecules 4 on the inclined region 6 It is presumed that, as shown in FIG. 3 (b), the liquid crystal molecules 4 begin to tilt at the same time, and then start to tilt all at once, that is, tilt all at once in a certain direction.
[0038]
The composite shape in which two or more triangles 11 are combined may be configured in any manner. For example, as shown in FIGS. 4A and 4B, two or more triangles 11 are formed in a fixed pattern. They may be arranged, or two or more triangles 11 may be arranged at random. FIG. 4A shows a form in which inclined regions 6 each formed of a triangle 11 having an acute angle portion 12 are radially arranged such that the acute angle portion 12 faces the center of the pixel. FIG. 4B shows an arrangement in which the inclined region 6 composed of a triangle 11 having an acute angle portion 12 is arranged so that the acute angle portion 12 is perpendicular to the center direction of the pixel, and the triangle 11 is arranged so as to draw a circle. It is a form.
[0039]
By thus arranging two or more triangles 11 to form a composite shape, the liquid crystal molecules 4 in the cell gap at the time of power-on can be tilted in multiple directions. As a result, a uniform display performance with a wide viewing angle can be obtained regardless of which direction the liquid crystal display device whose alignment is controlled is viewed from any direction.
[0040]
In particular, in the present invention, since the inclined region 6 shown in FIG. 4 is formed in a single pixel, the liquid crystal molecule alignment can be controlled for each pixel.
[0041]
FIG. 5 is a plan view showing an example in which different inclined regions are formed on both substrates. FIG. 5B shows a first substrate 1 in which inclined regions 6 are formed in the shape shown in FIG. A cell gap is formed with the second substrate 2 in which the inclined region 6 is formed in the shape, the liquid crystal 3 is injected therein, and the orientation of the liquid crystal molecules 4 when the power is turned on is shown. In the center of FIG. 5, a mode A in which triangles 11 formed on the upper and lower substrates 1 and 2 are arranged so as to be orthogonal to each other is described, and on the outside thereof, the liquid crystal molecules 4 are arranged from the vicinity of the first substrate 1. A mode B is shown in which the twisted state gradually turns toward the vicinity of the second substrate 2.
[0042]
As described above, the liquid crystal display device of the present invention can easily tilt the liquid crystal molecules on the tilted region in a certain direction when the power is turned on. It can be tilted, and the response time of the liquid crystal can be shortened. Furthermore, since the liquid crystal molecules in the cell gap can be regulated in a twisted structure, the liquid crystal molecules can be tilted in multiple directions, and as a result, the liquid crystal display device thus controlled in alignment can be viewed from any direction. Also, uniform display performance with a wide viewing angle can be obtained.
[0043]
Next, a substrate on which the above-described alignment layer is formed will be described. The first substrate 1 and the second substrate 2 constitute one of a color filter substrate 101 and a device (TFT) substrate 102, as shown in the liquid crystal display device of FIG.
[0044]
The color filter substrate 101 is a substrate in which a matrix-shaped color filter layer 107 is formed on a substrate 112. More specifically, R (red), G (green), and B (blue) This is a substrate including a color filter layer 107 forming a pixel region and a black matrix layer 108 formed on a peripheral portion of the pixel region to block leaked light. A common transparent electrode 109 is formed on the color filter layer 107, and a hydrophobic alignment film (not shown) for arranging directors of liquid crystal molecules in the normal direction of the substrate is formed on the common transparent electrode 109. . The color filter substrate 101 constituting the present invention is not particularly limited as long as it has a configuration generally used at present, and may have a configuration other than the above.
[0045]
On the other hand, the device substrate 102 is a substrate in which the matrix-shaped TFT elements 105 are formed as individual pixel regions on the substrate 112. More specifically, the pixel electrodes 104 arranged in a matrix on the inner surface of the substrate 112. A thin film field transistor (TFT) element 105 and a line electrode 106 are formed, and a hydrophobic alignment film (not shown) for arranging directors of liquid crystal molecules in a normal direction of the substrate is formed on the pixel electrode 104. ing. Note that the device substrate 102 constituting the present invention is not particularly limited as long as it has a configuration generally used at present, and may have a configuration other than the above.
[0046]
In the liquid crystal display device, a glass substrate or a transparent plastic substrate is used as the substrate 112, and the pixel electrode 104 and the transparent electrode 109 are made of, for example, indium tin oxide (ITO), indium oxide, indium zinc oxide (IZO). And the like. Further, a spacer is formed for setting the distance between the color filter substrate 101 and the device substrate 102 to a predetermined value, and the cell gap is set to a constant value. A polarizing plate 113 is provided outside each substrate (see FIG. 9), and a backlight is provided further outside the device substrate side.
[0047]
(Method of manufacturing liquid crystal display device)
Next, a method for manufacturing a liquid crystal display device will be described. The method for manufacturing a liquid crystal display device according to the present invention is a method for manufacturing a liquid crystal display device having the above-described configuration, and is characterized by (1) a first substrate surface (for example, a surface of a color filter substrate) and a second substrate surface. Forming a hydrophobic polymer film having a side chain whose side chain can be replaced and the chain length is long on at least one of the substrate surfaces (for example, the surface of a device substrate); Forming a tilted region (preferably a hydrophilic region) by substituting some side chains of the polymer film. Other manufacturing steps for manufacturing the liquid crystal display device, for example, steps for forming a color filter layer, a black matrix layer, a transparent electrode layer, a THT element and the like as shown in FIG. .
[0048]
In the step (1), as the resin for forming the hydrophobic polymer film having the side chain whose side chain can be substituted and the chain length is long, the above-mentioned side chain for forming the hydrophobic film is used. _{- (CH 2) n- (CF} 2) m-CF 3 (n is 2, m is 7) a is a fluorine-based silicone resin or side chain _{- (CH 2) n- (CF} 2) m-CF 3 ( n is 2 and m is 7), for example, a polyimide resin for forming a vertical alignment film. These resins are applied to the entire surface of both substrates by application means such as spin coating or various printing means.
[0049]
In the above step (2), the means for converting a part of the polymer film into an inclined region (hydrophilic region) includes, as shown in FIG. 6, (i) applying a hydrophobic film as a polymer film to the photocatalytic layer 34. A method of forming a hydrophilic region 36 by exposing only a side chain of an exposed portion by exposing with a mask 30 having a film. As shown in FIG. 7, (ii) coating a hydrophobic resin containing a photocatalyst After forming the photocatalyst-containing polymer film 37 by exposing the polymer film 37 to light, only the side chain of the exposed portion is replaced to form the hydrophilic region 36, and the like. .
[0050]
In the step (i), the hydrophobic polymer film 31 may be the above-mentioned fluorine-based silicone film or polyimide film. As shown in FIG. 6, a process using a mask having a photocatalyst layer is performed by first forming a mask 30 having a photocatalyst layer 34 formed on a substrate 32 having a mask pattern 33 formed thereon and a hydrophobic polymer film 31 being formed. The prepared first substrate and / or second substrate are prepared (FIG. 6A), and the mask 38 having the photocatalyst layer 34 and the hydrophobic polymer film 31 are arranged at a predetermined distance. This is a treatment method (hydrophilization treatment method) for forming a hydrophilic region 36 by facing the substrate (FIG. 6 (b)) and irradiating it with exposure light 35 (FIG. 6 (c)) (FIG. 6 (d)). )).
[0051]
The photocatalyst layer 34 is a layer in which titanium oxide as a photocatalyst is contained in a binder. The titanium oxide is preferably of an anatase type, and is preferably contained in the binder at a ratio of 20 to 40% by weight. The average particle size of the titanium oxide is preferably about 5 to 20 μm. Instead of titanium oxide, ZnO or the like may be used as a photocatalyst. When the photocatalyst layer 34 is irradiated with, for example, 380 nm or less exposure light 35, a photoelectrochemical reaction occurs in the photocatalyst particles, and the side chains of the exposed hydrophobic polymer film 31 are replaced with -OH groups. be able to. As a result, a part of the hydrophobic polymer film 31 can be changed to the hydrophilic region 36.
[0052]
Further, the interval between the mask 30 and the hydrophobic polymer film 31 is preferably an interval at which active oxygen species or the like generated by the photocatalytic reaction can be easily generated and acted in the gap, and is approximately 5 to 5. It is preferable to arrange them so as to have an interval of 20 μm.
[0053]
In the step (ii), examples of the hydrophobic polymer film 37 include a fluorine-based silicone film and a polyimide film containing the above-described photocatalyst. As shown in FIG. 7, the hydrophilic region is formed by first forming a mask 40 having a mask pattern 33 formed on a substrate 32 and a first substrate having a hydrophobic polymer film 31 containing a photocatalyst formed thereon. Alternatively, a second substrate is prepared (FIG. 7A), and the mask 40 and the hydrophobic polymer film 37 containing a photocatalyst are opposed to each other at a predetermined interval (FIG. 7B). This is a method of forming a hydrophilic region 36 (hydrophilizing treatment method) by irradiating the exposure light 35 (FIG. 7C) (FIG. 7D).
[0054]
The hydrophobic polymer film 37 contains titanium oxide as a photocatalyst in a binder. As described above, the titanium oxide is preferably of an anatase type, and is preferably contained in the binder at a ratio of 20 to 40% by weight. The average particle size of the titanium oxide is preferably about 5 to 20 μm. Instead of titanium oxide, ZnO or the like may be used as a photocatalyst. When the exposure light 35 having a wavelength of, for example, 380 nm or less is applied to the hydrophobic polymer film 37, a photoelectrochemical reaction occurs in the contained photocatalyst particles, and the side chains of the hydrophobic polymer film are converted to -OH groups. Can be replaced. As a result, a part of the hydrophobic polymer film can be changed to a hydrophilic region. Further, the distance between the mask 340 and the hydrophobic polymer film 37 is the same as in the case (i). In addition, comparing the step (i) with the step (ii), the step (i) can be more preferably applied.
[0055]
FIG. 8 is an explanatory diagram illustrating an example of a surface reaction in which a part of a hydrophobic polymer film changes into a hydrophilic region. FIG. 8 shows a state in which active oxygen species and the like attack the side chains on the surface of the hydrophobic polymer film, and break the bond between the side chains.
[0056]
In the treatment for causing the surface reaction shown in FIG. 8, it is preferable that the hydrophobic polymer film and the mask having the photocatalyst layer are arranged at a predetermined interval (for example, 5 to 20 μm). By arranging the hydrophobic polymer film and the mask having the photocatalytic layer at a predetermined interval, active oxygen species and the like generated by the photocatalytic reaction can be easily generated in the gap. The active oxygen species and the like include active oxygen or active hydroxyl groups generated based on the photoelectrochemical reaction in the photocatalyst particles, and the active oxygen species and the like attack the side chains (for example, alkyl side chains) shown in FIG. Then, the bond of the side difference is broken. The active oxygen species and the like are exchanged and bonded to the part where the side chain is cleaved, and the hydrophilicity is changed as shown in FIG.
[0057]
As described above, according to the method for manufacturing a liquid crystal display device of the present invention, an inclined region (hydrophilic region) capable of controlling the alignment of liquid crystal can be formed by an extremely easy process. And can contribute to cost reduction.
[0058]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0059]
(Example 1)
<Process of forming alignment control film on color filter substrate side>
First, a color filter substrate 1 on which ITO is formed as a transparent electrode 9 is prepared, and on the transparent electrode 9, a hydrophobic resin composition having a side chain whose side chain can be replaced and whose chain length is long (vertical resin). polyimide resin composition for orientation, manufactured by Japan Synthetic Rubber, JALS-688) was spin coated, at a thickness of 60 nm, the side chain is _{- (CH 2) n- (CF} 2) m-CF 3 (n is 2, m formed the hydrophobic polymer film of 7).
[0060]
Next, on the hydrophobic polymer film, a mask 30 having a photocatalyst layer 33 was arranged so as to keep an interval of about 20 μm, and then exposed to ultraviolet light having a wavelength of 200 to 370 nm. Exposed portions, as shown in FIG. 2, the side chain is _{- (CH 2) n- (CF} 2) m-CF 3 (n is 2, m is 7) is replaced by -OH groups from hydrophilic Changed to the sexual area.
[0061]
The mask 30 has a predetermined mask pattern 33 made of a chromium thin film formed on a substrate 32, and further has a thickness of 0.05 to 0.5 μm containing anatase type titanium oxide particles as a photocatalyst on the mask pattern 33. A photocatalyst layer 34 is formed. As shown in FIG. 4A, the mask pattern has a form in which hydrophilic regions 6 each formed of a triangle 11 having an acute angle portion 12 are radially arranged so that the acute angle portion 12 faces the center of the pixel. The size of each formed triangle was an isosceles triangle having an acute angle of 10 to 30 ° and a length of a side facing the acute angle 12 of 10 to 50 μm. The photocatalyst layer 34 contains about 10 to 100% by weight of titanium oxide particles in a binder resin (silicone resin). Here, 100% by weight of titanium oxide is the case where the photocatalyst layer 34 is formed only of titanium oxide.
[0062]
Thus, a color filter substrate in which a part of the hydrophobic polymer film on the transparent electrode of the color filter substrate was changed to a hydrophilic region was formed.
[0063]
<Process of forming alignment control film on device substrate side>
First, a device substrate 2 on which ITO is formed as a pixel electrode 4 is prepared, and a hydrophobic resin composition having a side chain whose side chain is replaceable and whose chain length is long (vertical alignment) is provided on the pixel electrode 4. Polyimide resin composition, manufactured by Japan Synthetic Rubber Co., Ltd., JALS-688) is spin-coated, has a thickness of 60 to 100 μm, and has a side chain of-(CH ₂ ) n-(CF ₂ ) m -CF ₃ (n is 2 , M formed a hydrophobic polymer film of 7).
[0064]
Next, a mask 30 having a photocatalyst layer 33 was arranged on the hydrophobic polymer film so as to keep an interval of about 10 to 25 μm, and then exposed to ultraviolet light having a wavelength of 200 to 370 nm. Exposed portions, as shown in FIG. 2, the side chain is _{- (CH 2) n- (CF} 2) m-CF 3 (n is 2, m is 7) is replaced by -OH groups from hydrophilic Changed to the sexual area.
[0065]
The mask 30 has a predetermined mask pattern 33 made of a chromium thin film formed on a substrate 32, and further has a thickness of 0.05 to 0.5 μm containing anatase type titanium oxide particles as a photocatalyst on the mask pattern 33. A photocatalyst layer 34 is formed. In the mask pattern, as shown in FIG. 4B, a hydrophilic region 6 composed of a triangle 11 having an acute angle portion 12 is arranged so that the acute angle portion 12 is orthogonal to the center direction of the pixel. Were arranged in such a manner as to draw. The size of each formed triangle was an isosceles triangle having an acute angle of 10 to 30 ° and a length of a side facing the acute angle 12 of 10 to 50 μm. When the above-described mask for the color filter substrate and the mask for the device substrate are superimposed and viewed in a plan view, the mask patterns are formed on both masks so that the triangle formed on each mask turns at an angle of 90 °. Was formed.
[0066]
The type and the amount of the photocatalyst constituting the photocatalyst layer 34 were the same as those of the above-described mask for the color filter substrate.
[0067]
Thus, a device substrate was formed in which a part of the hydrophobic polymer film on the pixel electrode of the device substrate was changed to a hydrophilic region.
[0068]
<Liquid crystal display device>
The color filter substrate formed by the above method and the device substrate were opposed to each other at a fixed distance, and liquid crystal was injected between them to form liquid crystal. In this liquid crystal display device, a hydrophobic polymer film for arranging directors of liquid crystal molecules in a direction normal to the substrate is formed on a color filter substrate and a device substrate. A hydrophilic region is formed that facilitates the director of the molecule to tilt in one direction.
[0069]
In this liquid crystal display device, since the liquid crystal molecules are shifted at an angle of about 90 °, the chiral agent contained in the liquid crystal could be reduced by about 2% as compared with the conventional liquid crystal display device. When the power of the liquid crystal display device was turned on, the response time of the liquid crystal was about 15 msec, compared to about 20 msec of the conventional liquid crystal display device.
[0070]
(Example 2)
In Example 1, a water-repellent fluorine-based silicone resin (TSL8233, manufactured by Toshiba Silicone Co., Ltd.) was used as a resin composition for forming a hydrophobic polymer film having a side chain whose side chain can be replaced and the chain length is long. TSL8114) with the side chain _{- (CH 2) n- (CF} 2) m-CF 3 (n is 2, m is other forming a hydrophobic polymer film 7), example 1 Similarly, a liquid crystal display device of Example 2 was configured.
[0071]
<Liquid crystal display device>
A liquid crystal display device was manufactured in the same manner as in Example 1. In this liquid crystal display device, since the liquid crystal molecules are shifted at an angle of about 90 °, the chiral agent contained in the liquid crystal could be reduced by about 2% as compared with the conventional liquid crystal display device. When the power of the liquid crystal display device was turned on, the response time of the liquid crystal was about 15 msec, compared to about 20 msec of the conventional liquid crystal display device.
[0072]
【The invention's effect】
As described above, according to the liquid crystal display device of the present invention, at least one of the alignment films is a hydrophobic polymer film having a long side chain, and a part of the polymer film includes Since the length of the chain is shorter than that of the side chain of the polymer film, and an inclined region having a side chain that inclines the director of the liquid crystal molecules with respect to the normal direction of the substrate is formed, when the power is turned on, Liquid crystal molecules begin to tilt easily in a certain direction. Then, the other liquid crystal molecules are simultaneously inclined starting from the liquid crystal molecules, so that the response time of the entire liquid crystal can be shortened. In addition, by arbitrarily forming the shape of the inclined region, the alignment of the liquid crystal molecules can be freely controlled.
[0073]
According to the manufacturing method of the liquid crystal display device of the present invention, since the inclined region can be formed by exposing the formed hydrophobic polymer film, without forming a conventional structure or a special thin film, An inclined region that enables control of the alignment of the liquid crystal can be formed by an extremely easy process. As a result, the liquid crystal display device can be manufactured efficiently, which can contribute to cost reduction.
FIG. 1 is a schematic diagram showing a change in director of liquid crystal molecules when a voltage is applied between substrates in a vertical alignment type liquid crystal display device.
FIG. 2 is an explanatory view showing one example of a polymer film of the present invention.
FIG. 3 is a schematic diagram illustrating the shape of a tilt region and the tilt direction of liquid crystal molecules.
FIG. 4 is a plan view showing an example of a shape (a) of an inclined region formed on a first substrate and a shape (b) of an inclined region formed on a second substrate.
FIG. 5 is a plan view showing an example in which different inclined regions are formed on both substrates, and an alignment form of liquid crystal molecules in the formed cell gap.
FIG. 6 is an explanatory diagram showing an example of a method for forming a tilt region using a photocatalyst.
FIG. 7 is an explanatory view showing another example of a method of forming a tilt region using a photocatalyst.
FIG. 8 is an explanatory diagram showing an example of a surface reaction in which a hydrophobic polymer film changes to hydrophilic.
FIG. 9 is a schematic sectional view showing an example of a general liquid crystal display device.
FIG. 10 is an explanatory diagram showing an example of a conventional multi-domain technology.
[Explanation of symbols]
Reference Signs List 1 first substrate 2 second substrate 3 liquid crystal 4 liquid crystal molecule 5 polymer film 6 inclined region (hydrophilic region)
11 triangle (inclined area)
Reference Signs List 12 acute angle portion 13 opposite sides 30 and 40 of acute angle portion Mask 31 Polymer film 32 Substrate 33 Mask pattern 34 Photocatalytic layer 35 Exposure light 36 Inclined region 37 Inclined film 101 containing photocatalyst Color filter substrate 102 TFT substrate 103 Liquid crystal 104 Pixel electrode 105 TFT element 106 Line electrode 107 Color filter layer 108 Black matrix layer 109 Common transparent electrode 112 Substrate 113 Polarizer Y substrate normal direction

Claims (8)

In a vertical alignment type liquid crystal display device including a first substrate, a second substrate, and a liquid crystal interposed between these substrates,
On the first substrate and the second substrate, alignment films for arranging directors of liquid crystal molecules in a direction normal to the substrate are respectively formed, and at least one of the alignment films is formed of a side chain. A hydrophobic polymer film with a long length.A part of the polymer film has a shorter chain length than a side chain of the polymer film, and the director of liquid crystal molecules is inclined with respect to the normal direction of the substrate. A liquid crystal display device, wherein an inclined region having a side chain to be formed is formed. The liquid crystal display device according to claim 1, wherein the inclined region is a hydrophilic region. The polymer film is a hydrophobic film formed of a fluorine-based silicone resin or a polyimide resin, and the inclined region is a hydrophilic region in which a hydrophilic group is added to the fluorine-based silicone film or the polyimide film. The liquid crystal display device according to claim 1 or 2, wherein: Side chain of the polymer _film, - (CH ₂₎ a _{n- (CF 2) m-CF} 3 (n represents an integer of 2 or more, m is an integer of seven or more, respectively), the side chain of the inclined region The liquid crystal display device according to any one of claims 1 to 3, which is a -OH group. Side chain of the polymer _film, - (CH 2) a _p-CH 3 (p is an integer of 7 or higher), the side chain of the inclined region, claim 1, characterized in that the -OH group 4. The liquid crystal display device according to any one of items 3 to 3. It has a first substrate, a second substrate, and a liquid crystal interposed between the substrates. Directors of liquid crystal molecules are arranged on the first substrate and the second substrate in a direction normal to the substrate. An alignment film is formed, and at least one of the alignment films is a hydrophobic polymer film having a long side chain, and a part of the polymer film is a polymer film. A method of manufacturing a liquid crystal display device of a vertical alignment mode, in which an inclined region having a side chain for inclining a director of liquid crystal molecules with respect to a substrate normal direction is formed, wherein the length of the chain is shorter than the side chain of
Forming a hydrophobic polymer film having a side chain whose side chain is replaceable and whose chain length is long on at least one substrate surface of the first substrate and the second substrate; and A method for manufacturing a liquid crystal display device, comprising a step of forming an inclined region by replacing a part of side chains of a film. 7. The method according to claim 6, wherein in the step of forming the inclined region, the substitution of the side chain of the polymer film is a hydrophilic treatment. The method for manufacturing a liquid crystal display device according to claim 7, wherein the hydrophilic treatment is performed by an exposure treatment using a mask having a photocatalyst layer.

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