JP2005070530A - Liquid crystal display element and method for manufacturing the same, and projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display element with excellent contrast characteristics by adequately forming an alignment layer even on a place where there is a difference in level on the surface and preventing a display performance from lowering due to light leakage and abnormal alignment. <P>SOLUTION: The liquid crystal display element 10 is constructed so as to form an on-chip spacer (OCS) 114 on a counter substrate 102. Because the OCS 114 and its peripheral region form a shade in oblique deposition and no alignment layer is formed thereon, a first alignment layer 118 is separately formed thereon with such methods as offset printing, spin-coating or ink-jet printing. Other alignment layers, a second alignment layer 119 and an alignment layer 116 for a TFT array substrate 101, are formed with the oblique deposition. Thereby the alignment layer is formed on a whole area of the counter surface of the substrate without omission even when the difference in level exists thereon. Consequently a reverse tilt domain is prevented from occurring, a disclination line occurring on a boundary between a normal tilt region and the reverse tilt domain is prevented, so as to prevent the light leakage and contrast lowering. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display element in which alignment abnormality is prevented and display performance is improved, a manufacturing method thereof, and a projection display device using the same.

In recent years, liquid crystal display elements have been used in various fields such as computer display devices, television receivers, and projectors because of their light weight and low power consumption.
In a projection display element such as a liquid crystal projector, light emitted from a light source is separated into red, green, and blue, and each color light is modulated by three light valves composed of liquid crystal display elements, and the color after modulation The light is combined and projected on the projection surface. As a light valve for such a liquid crystal projector, an active matrix type liquid crystal display element driven by a thin film transistor (TFT) is generally used.

In general, an active matrix liquid crystal display element has a TFT array substrate on which switching elements and display electrodes are formed, and a counter substrate provided to face the TFT array substrate. A liquid crystal material is enclosed between them. In order for the liquid crystal material to exhibit desired electro-optical characteristics, it is necessary to make the substrate gap uniform over the entire display region. In order to control the substrate gap, conventionally, balls such as plastic beads have been used as spacers (see, for example, Patent Document 1). However, in the method using a spacer such as a sphere, there are problems that the uniformity and dispersibility of the diameter of the sphere are poor and the light transmittance is lowered by the spacer located in the effective pixel region.
Therefore, in recent years, a method of forming a columnar spacer made of a photoresist material on any substrate has been proposed. Columnar spacers can be selectively formed in non-effective pixel areas, so there is an advantage that light can be used efficiently and the substrate gap can be controlled with very high precision. Has attracted attention and has been adopted as a technology that enables

In the liquid crystal display element, an alignment film for aligning liquid crystal molecules is formed on the surface of the substrate enclosing the liquid crystal material, and alignment processing is performed. In recent years, an inorganic material such as SiO ² has been used as the alignment film in place of an organic material such as polyimide that has been conventionally used. Inorganic materials have the advantages of less reliability and longer life than organic materials due to less degradation and reaction due to external influences. In addition, since the alignment process can be performed without using a conventional rubbing method, the number of steps can be reduced and impurities such as dust can be prevented (see, for example, Patent Document 2).

JP-A-8-536355 JP 2000-227595 A

By the way, the alignment film made of an inorganic material is usually formed by vapor deposition. Therefore, in a liquid crystal display element in which a step is generated on the substrate surface due to TFT wiring or a columnar spacer is formed, a shadow region where an alignment film is not deposited occurs. That is, the step of the TFT wiring part and the columnar spacer are protrusions, and as shown in FIG. 7, for example, depending on the deposition direction, a shadow 320 is generated by the step of the columnar spacer 310, etc. An area occurs. The region where the alignment film is not formed is a region having a pretilt angle opposite to a normal pretilt angle in the liquid crystal layer, and is called a reverse tilt domain.
In general, the reverse tilt domain is often located where the influence of a lateral electric field is likely to occur, and the transmittance is different from that of a normal region. Therefore, display defects such as unevenness and streaks may occur on the display screen. In addition, a disclination line may be generated between the normal region and the reverse tilt domain, causing light leakage and reducing the contrast.

  In order to prevent light leakage due to such a reverse tilt domain, Patent Document 1 proposes a method of changing the columnar spacer position to make the light leakage inconspicuous, but there is an unoriented region. It is not fundamentally improved and light leakage cannot be completely eliminated.

The present invention has been made in view of such problems, and its purpose is to appropriately form an alignment film even in a region where there is a step due to wiring, columnar spacers, etc., and display due to light leakage or alignment abnormality. An object of the present invention is to provide a liquid crystal display element having good characteristics such as contrast and a method for manufacturing the same by preventing a decrease in performance.
Another object of the present invention is to provide a projection display device capable of projecting and displaying a desired image in a state where characteristics such as contrast are good.

In order to solve the above problems, a liquid crystal display element of the present invention includes a first substrate having an alignment film formed on an opposing surface, and a second substrate disposed substantially parallel to the first substrate. A liquid crystal display element having a liquid crystal layer formed between the first substrate and the second substrate,
The alignment film (second alignment film) formed in another region of the facing surface in a portion where a step is generated on the surface of the facing surface of the first substrate and a region around the step. Are characterized in that different types of alignment films (first alignment films) are formed.

  In the liquid crystal display device having such a configuration, for example, a step generated by a spacer or a wiring pattern for maintaining the thickness of the liquid crystal layer and a region around the step are different from other regions. An alignment film that can be appropriately formed even if there is a film is formed. That is, by applying different types of alignment films, such as different alignment films or alignment films formed by different forming methods, to the same substrate, the alignment film is formed without omission over the entire surface of the substrate. More specifically, for example, for an area where an alignment film is not formed by vapor deposition due to a step, an alignment film formed by a method other than vapor deposition is arranged, whereby the alignment film is formed on the entire surface of the substrate. I try to do it. Therefore, it is possible to prevent the occurrence of a reverse tilt domain, to prevent the occurrence of a disclination line that occurs at the boundary between the normal tilt region and the reverse tilt domain, and to prevent light leakage and a decrease in contrast.

Preferably, the different types of alignment films are alignment films formed by applying an alignment film material using any one of offset printing, spin coating, and ink jet.
Preferably, the different types of alignment films are alignment films formed by applying any one of linearly polarized light irradiation, rubbing or ion beam irradiation.

Preferably, the different types of alignment films are alignment films formed of an inorganic material.
There is a possibility that the organic substance has an alignment state that is influenced by the polar interaction with the liquid crystal, and a desired minute inclination cannot be obtained. Further, when a conductor such as metal is used, electrification flows on the surface, and there is a possibility that uniform ON and OFF cannot be obtained on the front surface. Therefore, an inorganic dielectric or a semiconductor is suitable for such an alignment film material.

  Moreover, the alignment film formed in the other area | region of the opposing surface is suitable for the alignment film formed of the material which has a single IV group element, such as a silicon | silicone and germanium, a mixture, or a compound as a main component.

The method of manufacturing a liquid crystal display element according to the present invention includes a first substrate having an alignment film formed on an opposing surface, a second substrate disposed substantially parallel to the first substrate, and the first substrate. A method of manufacturing a liquid crystal display element having a liquid crystal layer formed between one substrate and the second substrate,
Forming the alignment film in a portion where a step is generated on the surface of the facing surface of the first substrate and a region around the step, and forming the alignment film in another region of the facing surface And the alignment film is formed by a different method in the two steps.

The projection display device of the present invention includes a light source, a condensing optical system that guides light emitted from the light source to a liquid crystal display element, and a projection optical system that expands and projects light modulated by the liquid crystal display element. A projection type display device comprising:
The liquid crystal display element includes a first substrate having an alignment film formed on an opposing surface, a second substrate disposed substantially parallel to the first substrate, the first substrate, and the second substrate. A liquid crystal layer formed between the first substrate and a region where a step is generated on the surface of the facing surface of the first substrate, and another region of the facing surface in a region around the step. A different type of alignment film is formed from the alignment film formed in (1).

As described above, according to the present invention, an alignment film is appropriately formed even in a region where there is a step due to wiring, columnar spacers, etc., and the display performance is not deteriorated due to light leakage or alignment abnormality. A liquid crystal display element with favorable characteristics and a method for manufacturing the same can be provided.
In addition, it is possible to provide a projection display device capable of projecting and displaying a desired image with good characteristics such as contrast.

Hereinafter, the present invention will be described with reference to FIGS.
FIG. 1 is a plan view of a liquid crystal display element according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a configuration of a pixel portion of the liquid crystal display element, and FIG. 3 is a schematic view showing a configuration of the pixel portion. FIG. 4 is a flow chart for explaining a method of manufacturing the liquid crystal display device, FIG. 5 is a diagram showing a vapor deposition device used for manufacturing the liquid crystal display element, and FIG. 6 is a liquid crystal display thereof. It is a figure which shows the structure of the optical system of the projector suitable using an element.
Note that the liquid crystal display element described in this embodiment is an active matrix small liquid crystal display element for a projection display device (projector).

First Embodiment First, a first embodiment will be described with reference to FIGS.
First, a schematic configuration of the liquid crystal display element 10 of the first embodiment will be described.
As shown in FIG. 1, the liquid crystal display element 10 has an image display area 11 used for actual image display and a non-image display area 12 at the periphery thereof.
As shown in FIG. 2, the image display area 11 and the non-image display area 12 are configured such that a TFT array substrate 101 and a counter substrate 102 are arranged to face each other at a predetermined interval.

In a region corresponding to the image display region 11 shown in FIG. 1 on the upper surface of the TFT array substrate 101 (the surface facing the counter substrate 102), a large number of pixel electrodes 103 having the same shape shown in FIG. Be placed. As shown in FIGS. 2 and 3, the pixel electrode 103 is connected to the signal line 107 and the scanning line 113 via a TFT 106 made of amorphous silicon, polysilicon, or the like. Further, as shown in FIG. 2, a protective film 117 is formed on the TFT 106 (in the region where the pixel electrode 103 is formed, between the pixel electrode 103). An alignment film 116 is formed on the pixel electrode 103 (on the protective film 117 in a region where the pixel electrode 103 is not formed). The alignment film 116 is formed by oblique vapor deposition in the same manner as a second alignment film 119 of the counter substrate 102 described later.
The TFT array substrate 101 is made of, for example, a quartz substrate, and the pixel electrode 103 is made of, for example, a transparent conductive thin film such as an ITO film (indium tin oxide film).
The operations of the pixel electrode 103 and the TFT 106 will be described in detail later.

As shown in FIG. 2, a transparent counter electrode 104 is formed on the entire surface corresponding to the image display area 11 shown in FIG. 1 on the lower surface of the counter substrate 102 (the surface facing the TFT array substrate 101). .
On the surface of the counter electrode 104 on the TFT array substrate 101 side, an on-chip spacer (OCS) 114 as a gap material is formed in a predetermined arrangement. The OCS 141 has a columnar cross section as shown in the drawing and is formed at a height that defines the distance between the TFT array substrate 101 and the counter substrate 102 by lithography process and development / etching process. As a result, in the image display area 11, the distance between the TFT array substrate 101 and the counter substrate 102 is maintained at a predetermined distance. In the present embodiment, the OCS 114 has a width of 2 μm to 3 μm and a height of 2.7 ± 0.5 μm.

In addition, alignment films 118 and 119 are formed on the surface of the counter electrode 104 on the TFT array substrate 101 side. There are two types of alignment films, a first alignment film 118 and a second alignment film 119.
The first alignment film 118 is an upper surface of the counter electrode 104 and a region where the second alignment film 119 formed by oblique deposition is difficult to be formed, that is, a portion where a step is generated on the upper surface of the counter electrode 104 and It is formed in the surrounding area. In the present embodiment, it is formed on the surface of the OCS 114 shown in FIG. 2 and the vicinity thereof, and the peripheral region of the step due to the wiring (not shown).
The first alignment film 118 is formed in a region slightly wider than the convex portion and the concave portion forming the step. Specifically, for the 10 μm prismatic OCS 14 shown in FIG. 2, the first alignment film 118 is formed in a 14 μm square region that is 2 μm larger in the horizontal and vertical directions. For the wiring, the first alignment film 118 is formed in a region 2 μm larger on the left and right than the width of each wiring. This value is based on an experimental result that there is a possibility that an abnormal alignment region having a maximum of 2 μm may occur in a prism having a side of 10 μm.

  The second alignment film 119 is formed in a region other than the region where the first alignment film 118 is formed on the counter electrode 114. The second alignment film 119 is formed by oblique deposition.

In the counter substrate 102, a light shielding film 105 is provided between the counter substrate 102 and the counter electrode 104 in a region other than the opening region (light passage region) of each pixel portion.
The counter substrate 102 is made of, for example, a glass substrate or a quartz substrate, and the counter electrode 104 is formed of a transparent conductive thin film such as an ITO film like the pixel electrode 103, for example. The OCS 114 is formed of an acrylic resin, a polyimide resin, a novolac resin, or the like.

  Such a TFT array substrate 101 and the counter substrate 102 are joined by a seal portion 13 formed so as to surround the image display region 11 in the non-image display region 12 shown in FIG. Although not shown in the figure, an OCS similar to the OCS 114 formed in the image display area 11 is also arranged in the seal portion 13, so that the interval between the TFT array substrate 101 and the counter substrate 102 is also predetermined in the non-image display area 12. Maintained at an interval of.

In the liquid crystal display element 10, liquid crystal is sealed in a space surrounded by the TFT array substrate 101, the counter substrate 102, and the seal portion 13 formed as described above.
Further, a polarizer or the like (not shown) is provided outside the TFT array substrate 101 and the counter substrate 102 to constitute the liquid crystal display element 10.

Next, the configuration and operation of the pixel portion of the liquid crystal display element 10 will be described.
As shown in FIGS. 2 and 3, a pixel switching TFT 106 that controls switching of the pixel electrode 103 is provided in the vicinity of the pixel electrode 103 that forms the image display region 11 of the liquid crystal display element 10. . A source 108 of the TFT 106 is electrically connected to a signal line 107 to which a pixel signal is supplied. The gate of the TFT 106 is electrically connected to a scanning line 109 to which a scanning signal is applied at a predetermined timing. Further, the pixel electrode 103 is electrically connected to the drain 110 of the TFT 106.

  Accordingly, the pixel signal supplied from the signal line 107 is applied to the pixel electrode 103 at a predetermined timing by opening the TFT 106 serving as a switching element for a certain period (making it conductive). As a result, this pixel signal acts on the liquid crystal 111 between the pixel electrode 103 and the counter electrode 104 of this pixel portion, and information corresponding to this pixel signal is written into the liquid crystal 111.

A pixel signal written to the liquid crystal through the pixel electrode 103 is held for a certain period with the counter electrode 104 formed on the counter substrate 102.
The liquid crystal 111 modulates light and enables gradation display by changing the orientation and order of the molecular assembly according to the applied voltage level. That is, incident light can pass through the liquid crystal portion according to the applied voltage, and as a result, the liquid crystal display element 10 as a whole emits light having a contrast according to the pixel signal.

  Further, in order to prevent a pixel signal held between the pixel electrode 103 and the counter electrode 104 from leaking, a storage capacitor 112 is added in parallel with the capacitor of the liquid crystal 111 as shown in FIG. Thereby, the holding characteristics are improved, and display with a high contrast ratio can be performed. In order to form such a storage capacitor 112, a resistance Cs line 113 is provided on the TFT array substrate 101 as shown in FIG.

Next, a method for manufacturing the liquid crystal display element 10 having such a configuration will be described with reference to FIG. 4, particularly focusing on the alignment film forming step in the counter substrate 102.
In the counter substrate 102, first, the light shielding layer 105 and the counter electrode 104 shown in FIG. 2 are formed, and the columnar OCS 14 is formed on the counter electrode 104 (step S110).
The OCS 14 first applies PWER (manufactured by Tokyo Ohka Kogyo Co., Ltd.) as a transparent photoresist on the counter electrode 104 to a thickness of 3 μm by spin coating. Next, exposure is performed by irradiating ultraviolet rays through a photomask having a pattern formed at the position where the columnar OCS 14 is formed. Then, development and etching are performed to form the columnar OCS 14.

After the columnar OCS 14 is formed, an alignment film is formed next. As described above, two types of alignment films, the first alignment film 118 and the second alignment film 119, are formed on the contact surface of the counter substrate 102 with the liquid crystal 111 (the surface facing the TFT array substrate 101). The
In forming the alignment film, first, the counter substrate 102 is washed with a neutral detergent, and after washing, left in a 120 ° C. atmosphere for 20 minutes to be dried (step S120).
Next, the first alignment film 118 is formed (step S130). The first alignment film 118 is formed in a region in the vicinity of the wiring and the OCS 14 including the wiring and the OCS 14, and a region that shadows the wiring and the OCS 14 when the second alignment film 119 is formed by oblique deposition. In this embodiment, as described above, for the 10 μm prismatic OCS 14 shown in FIG. 2, the first alignment film 118 is formed in a 14 μm square region that is 2 μm larger in the horizontal and vertical directions. . For the wiring, the first alignment film 118 is formed in a range 2 μm larger than the width of each wiring.

  First, using a plate (mask) in which a pattern is formed in the formation region of the first alignment film 118, polyimide (PI), which is a first alignment film material, is printed on the counter substrate 102 by offset printing. It is left to stand in a 100 ° C. atmosphere for 1 minute and dried (step S131). In the present embodiment, soluble polyimide AL1256 manufactured by Nippon Synthetic Rubber Co., Ltd. is used as the first alignment film material.

After the alignment film material is formed by printing, post-baking is performed in an atmosphere at 180 ° C. for 1 hour, and the solvent is dried (step S132).
Next, a quartz photomask in which openings are formed (transmitting light) in the first alignment film forming region, that is, the TFT wiring portion, the OCS 114, and their peripheral upper, lower, left, and right 2 μm regions is overlaid on the counter substrate 102. The surface to which the polyimide is applied is irradiated with polarized ultraviolet rays (step S133). The ultraviolet rays to be irradiated are linearly polarized polarized ultraviolet rays having a central wavelength of 313 nm, which are irradiated on the entire surface of the polyimide coating surface at a density of 1 J / cm ² . From the viewpoint of retention rate, the amount of ultraviolet irradiation light is preferably 1 J / cm ² or less.

Next, polarized ultraviolet rays are irradiated from an oblique direction inclined by, for example, 70 ° with respect to the normal line of the substrate (step S134). Thereby, the first alignment film 118 in which the liquid crystal molecules are aligned in the direction orthogonal to the polarization direction of the polarized ultraviolet light is formed.
Note that the tilt of the irradiation direction of the polarized ultraviolet light is not limited to 70 °, and may basically be tilted with respect to the normal line of the substrate.
As a method for realizing the pretilt angle, a method such as rubbing can be applied in addition to the oblique irradiation of the polarized ultraviolet rays described above.

Next, the second alignment film 119 is formed (step S140). The second alignment film 119 is formed by oblique vapor deposition using the vapor deposition apparatus 200 shown in FIG. 5 in a region where the first alignment film 118 on the counter electrode 104 is not formed.
Vapor deposition sources include silicon oxide containing silicon monoxide and silicon dioxide, oxides such as titanium oxide, zirconium oxide and tantalum oxide, fluorides such as magnesium fluoride, sulfides such as zinc sulfide, silicon, germanium, etc. A raw material mainly composed of a simple substance, a mixture or a compound of group IV elements may be used. In this embodiment, silicon monoxide powder is used.

The vapor deposition apparatus shown in FIG. 5 is a vapor deposition apparatus that can maintain the alignment film forming surface at a desired angle with respect to the scattering direction of the vapor deposition material.
The vapor deposition apparatus 200 includes a vacuum chamber 210 and an exhaust system 220. The vacuum chamber 210 includes a substrate holder 211, a rotation mechanism 212, a vapor deposition source 213, and a film thickness meter 214. The substrate holding unit 211 holds a plurality of substrates with the alignment film forming surfaces aligned on the same surface. The rotation mechanism 212 holds the substrate holding part 211 in a desired direction. The substrate holding unit 211 and the rotation mechanism 212 hold the substrate at a position where the alignment film forming surface is at a predetermined angle with respect to the scattering direction of the vapor deposition material from the vapor deposition source.

Further, the vapor deposition source 213 is a resistance heating boat in which a slit-shaped opening is formed, and the film thickness meter 214 is a crystal resonator film thickness meter.
The exhaust system 220 has a main pump 221. The main pump 221 is a diffusion pump, a turbo molecular pump, a cryopump, or the like, and is an oil diffusion pump in this embodiment.

With such a vapor deposition apparatus 200, the counter substrate 102 is held obliquely with respect to the vapor deposition source 213, and is used for vapor deposition, so that the second alignment film 119 formation region of the counter substrate 102 has a second region. An alignment film material is deposited from an oblique direction.
In the present embodiment, the conditions for forming the alignment film are as follows: the incident angle as viewed from the direction parallel to the substrate is 70 degrees, and the film thickness is measured by a film thickness meter installed at a distance perpendicular to the substrate from the evaporation source during film formation. The thickness d (nm) was 60.

Although not shown, the TFT array substrate 101 is formed on the entire surface using the same film material as that of the second alignment film 119 by the same oblique deposition as that for forming the second alignment film 119. To do.
Then, a seal pattern formed except for the liquid crystal injection port is formed on the counter substrate 102 formed in this way using an adhesive made of a photo-curing resin or a thermosetting resin, and overlapped with the TFT array substrate 101. Matching and joining are performed (step S150).
Next, a liquid crystal material is injected from the liquid crystal injection port, and the injection port is sealed with an ultraviolet curable resin (step S160). Thereby, the liquid crystal display element 10 is manufactured.

Regarding the liquid crystal display device manufactured in this way, when an abnormal alignment region was observed, there was a possibility that an abnormal alignment region would occur with a width of about 2 μm around the OCS. It was improved to a state where it could hardly be observed. Moreover, when the image quality was observed, a good image quality without light leakage could be obtained.
As described above, according to the first embodiment, it is possible to appropriately form an alignment film even in a region where the OCS 114 is present, and to prevent display performance from being deteriorated due to light leakage or alignment abnormality.

Second Embodiment A second embodiment of the present invention will be described.
As a second embodiment, unlike the first embodiment described above, a method of forming the first alignment film 118 by stacking an organic alignment film material on the counter substrate 102 by a spin coating method will be described. Other contents such as the basic configuration of the liquid crystal display element are substantially the same as those of the first embodiment described above, and a description thereof will be omitted.

In the second embodiment, in step S131 of the flowchart shown in FIG. 4, the first alignment film material is applied onto the counter substrate 102 by spin coating. That is, first, a 2.0 wt% solution of the first alignment film material (soluble polyimide AL1256: manufactured by Nippon Synthetic Rubber Co., Ltd.) using γ-butyrolactone is prepared. Next, a metal mask in which an opening is formed only at a position where the first alignment film 118 is formed is created, and thereby the counter substrate 102 is masked. Then, a solution containing the alignment film material is applied onto the counter substrate 102 by spin coating. Thereby, the alignment film material of the first alignment film is stacked in a desired region on the counter substrate 102.
As in the first embodiment, post-baking is performed on this alignment film material in the processes after step S132, and polarized ultraviolet rays are irradiated from the orthogonal direction and the inclination direction, thereby forming the first alignment film 118. The steps after the formation of the second alignment film 119 in step S140 are the same as those in the first embodiment described above.

  The first alignment film 118 may be formed by applying the spin coating method in this way. Also in the liquid crystal display element manufactured by forming the first alignment film 118 by such a method, the alignment abnormality is improved so that it can hardly be observed in the entire region, and a good image quality without light leakage can be obtained. did it. Also, with this method, the amount of alignment film material used can be greatly reduced compared to the method using offset printing of the first embodiment. This method using spin coating is particularly effective when the alignment film material has low viscosity.

Third Embodiment A third embodiment of the present invention will be described.
As a third embodiment, a method for forming the first alignment film 118 by stacking an organic alignment film material on the counter substrate 102 by an inkjet method, which is further different from the first embodiment and the second embodiment described above. . Other contents such as the basic configuration of the liquid crystal display element are substantially the same as those of the first embodiment described above, and a description thereof will be omitted.

In the third embodiment, in step S131 of the flowchart shown in FIG. 4, the first alignment film material is applied onto the counter substrate 102 by the ink jet method. That is, first, a 2.0 wt% solution of the first alignment film material (soluble polyimide AL1256: manufactured by Nippon Synthetic Rubber Co., Ltd.) using γ-butyrolactone is prepared. Next, a solution is discharged to a place where the first alignment film 118 is formed by an ink jet method, that is, by using an ink jet, and an alignment film material is attached to the place. Thereby, the alignment film material of the first alignment film is stacked in a desired region on the counter substrate 102. The ink jet nozzle used in this embodiment is a piezo ink jet nozzle.
As in the first embodiment, post-baking is performed on this alignment film material in the processes after step S132, and polarized ultraviolet rays are irradiated from the orthogonal direction and the inclination direction, thereby forming the first alignment film 118. The steps after the formation of the second alignment film 119 in step S140 are the same as those in the first embodiment described above.

  The first alignment film 118 may be formed by applying the ink jet method in this way. Also in the liquid crystal display element manufactured by forming the first alignment film 118 by such a method, the alignment abnormality is improved so that it can hardly be observed in the entire region, and a good image quality without light leakage can be obtained. did it. In particular, according to this ink jet method, the amount of the alignment film material used can be significantly reduced as compared with the offset printing method of the first embodiment. Further, the processing time can be greatly shortened as compared with the method using the spin coater of the second embodiment.

Fourth Embodiment A fourth embodiment of the present invention will be described.
As a fourth embodiment, a method for forming the first alignment film 118 using an inorganic material will be described. The rest of the content, such as the basic configuration of the liquid crystal display element, is substantially the same as in the first embodiment described above, and a description thereof is omitted.

In the fourth embodiment, as step S130 of the flowchart shown in FIG. 4, an inorganic alignment film material such as ODS-E manufactured by Chisso is discharged to a place where the first alignment film 118 is formed by an inkjet method. . Thereby, the first alignment film 118 made of an inorganic material is formed in a desired region on the counter substrate 102. The ink jet nozzle used in this embodiment is a piezo ink jet nozzle.
The steps after the formation of the second alignment film 118 in step S140 are the same as those in the first embodiment described above.

Thus, the first alignment film 118 may be formed of an inorganic material.
Also in the liquid crystal display element manufactured by forming the first alignment film 118 by such a method, the alignment abnormality is improved so that it can hardly be observed in the entire region, and a good image quality without light leakage can be obtained. it can. In this embodiment, since all alignment films are formed of an inorganic material, a device with particularly high light resistance and high reliability can be manufactured. Further, according to this method, the first alignment film 118 is formed only by the printing process by the ink jet method, so that the manufacturing process can be simplified.
In addition, as a method of forming the first alignment film 118 with an inorganic material, the first alignment film 118 may be formed by offset printing similar to the first embodiment or spin coating same as that of the second embodiment.

Fifth Embodiment A fifth embodiment of the present invention will be described.
As a fifth embodiment, a method for forming the first alignment film 118 by applying an alignment material and then aligning it by irradiation with an ion beam will be described. The basic configuration of the liquid crystal display element is substantially the same as that of the first embodiment described above, and a description thereof is omitted.

  In the fifth embodiment, in step S130 of the flowchart shown in FIG. 4, first, for example, a 2.0 wt% solution using γ-butyrolactone as a solvent of soluble polyimide JAL445 manufactured by Nippon Synthetic Rubber Co., Ltd. is prepared. Next, this solution is discharged to a place where the first alignment film 118 is formed by an inkjet method. In this embodiment, piezo ink jet noise is used. As a result, the alignment film material is attached to a desired region on the counter substrate 102.

Next, this alignment film material is irradiated with an ion beam. The ion beam used was an ion beam irradiation machine manufactured by Nissin Ion Equipment Co., Ltd. The beam irradiation conditions were as follows: beam size: 200 mm × 60 mm, ion species: N2, ion energy: ˜1500 eV, transport speed 20 mm / sec, incident angle: 40 degrees from the normal spring direction, and one-step irradiation.
As a result, a film having good orientation was formed as the first alignment film 118.
The steps after the formation of the second alignment film 119 in step S140 are the same as those in the first embodiment described above.

The first alignment film 118 may be formed by irradiation with an ion beam in this way.
Also in the liquid crystal display element manufactured by forming the first alignment film 118 by such a method, the alignment abnormality is improved so that it can hardly be observed in the entire region, and a good image quality without light leakage can be obtained. it can.
In this case, as the alignment film material, in addition to the polyimide described above, a polyamic acid material such as SE7492 manufactured by Nissan Chemical Co., Ltd. may be used.

As a suitable device to which the liquid crystal display element of each embodiment described above is applied, there is a projection display device (projector). In the optical system of this projector, as shown in FIG. 6, the light emitted from the lamp (light source) is color-separated into three primary colors of red (R), green (G) and blue (B), and is displayed on a liquid crystal display. The light is guided to the element (condensing optical system), and in each liquid crystal display element, the guided light is modulated to control the transmittance. Then, the modulated light of each color is synthesized by a cross prism, emitted from a projection lens, and a desired image is enlarged and displayed on a screen or the like (enlarged projection optical system).
In such a projector, light leakage or a decrease in contrast due to the occurrence of a disclination line significantly affects the display image. Therefore, by applying the liquid crystal display element of this embodiment, it is possible to prevent deterioration of display performance due to an abnormal alignment such as a reverse tilt domain, which is very effective.

The present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the present invention.
For example, in the fifth embodiment described above, the alignment film material is irradiated with an ion beam when the first alignment film 118 is formed. However, when the stacking of the alignment film material of the second alignment film 119 is finished, these materials are used. The entire thin film material may be irradiated with an ion beam. By doing so, the orientation can be improved as a whole, which is effective.

  In the above-described embodiment, the second alignment film is formed after the first alignment film is formed. However, first, the second alignment film is formed by, for example, oblique vapor deposition, and then the shadow of the oblique vapor deposition is formed. The first alignment film may be formed by the various methods described above other than oblique vapor deposition.

The shape of the OCS is not limited to a prism, and may be a cylinder.
The OCS may be formed on the TFT array substrate 101. In that case, the first alignment film 118 may be formed on the TFT array substrate 101.
Further, the liquid crystal display element of the present invention is not limited to a projector, and can be applied as a display element of an arbitrary device such as an EVF (Electric View Finder) or a portable device.

FIG. 1 is a plan view showing a schematic overall configuration of a liquid crystal display element according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a detailed configuration of a pixel portion of the liquid crystal display element shown in FIG. FIG. 3 is a schematic circuit diagram showing an electrical circuit configuration of the pixel portion shown in FIG. FIG. 4 is a flowchart for explaining a method of manufacturing the liquid crystal display element shown in FIG. FIG. 5 is a diagram showing a configuration of a vapor deposition apparatus used in the manufacturing process shown in FIG. FIG. 6 is a diagram showing a configuration of an optical system of a projector using the liquid crystal display element shown in FIG. FIG. 7 is a diagram for explaining a shadow portion during oblique deposition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display element, 101 ... TFT array substrate, 102 ... Counter substrate, 103 ... Pixel electrode, 104 ... Counter electrode, 105 ... Light-shielding layer, 106 ... TFT, 107 ... Signal line, 108 ... Source, 109 ... Scanning line, DESCRIPTION OF SYMBOLS 110 ... Drain, 111 ... Liquid crystal layer, 112 ... Storage capacity, 113 ... Cs line, 114 ... On-chip spacer (OCS), 116 ... TFT array substrate side alignment film, 117 ... Protective film, 118 ... First alignment film, DESCRIPTION OF SYMBOLS 119 ... 2nd alignment film, 200 ... Vapor deposition apparatus, 210 ... Vacuum chamber, 211 ... Substrate holding part, 212 ... Rotation mechanism, 213 ... Vapor deposition source, 214 ... Film thickness meter, 220 ... Exhaust system, 221 ... Main pump

Claims (14)

A first substrate having an alignment film formed on the opposing surface, a second substrate disposed substantially parallel to the first substrate, and between the first substrate and the second substrate A liquid crystal display element having a liquid crystal layer to be formed,
An alignment film of a type different from the alignment film formed in another region of the facing surface is formed in a portion where a step is generated on the surface of the facing surface of the first substrate and a region around the step. A liquid crystal display element characterized by being formed. The regions where the different kinds of alignment films are formed are steps formed by spacers or wiring patterns for maintaining the thickness of the liquid crystal layer constant, and regions around the steps. The liquid crystal display element according to claim 1. The region where the different type of alignment film is formed is a region where the alignment film is not formed due to the step when the alignment film of the other region on the opposite surface is formed by vapor deposition. The liquid crystal display element according to claim 1 or 2. 4. The alignment film according to claim 1, wherein the different type of alignment film is an alignment film formed by applying an alignment film material using any one of offset printing, spin coating, and inkjet. The liquid crystal display element as described. 5. The alignment film according to claim 1, wherein the different types of alignment films are alignment films formed by applying any one of linearly polarized light irradiation, rubbing, and ion beam irradiation. A liquid crystal display element according to 1. The liquid crystal display element according to claim 1, wherein the different types of alignment films are alignment films formed of an inorganic material. The alignment film formed in the other region of the facing surface is an alignment film formed of a material containing a single group IV element, a mixture, or a compound. Liquid crystal display element. A first substrate having an alignment film formed on the opposing surface, a second substrate disposed substantially parallel to the first substrate, and between the first substrate and the second substrate A liquid crystal display device having a liquid crystal layer to be formed,
Forming the alignment film in a portion where a step is generated on the surface of the facing surface of the first substrate and a region around the step, and forming the alignment film in another region of the facing surface And forming the alignment film by a different method in the two steps. In the other area of the facing surface, an alignment film material is laminated by vapor deposition to form the alignment film,
The method for producing a liquid crystal display element according to claim 8, wherein an alignment film material is formed by laminating an alignment film material by a method other than vapor deposition in a place where a step is generated on the surface and a region around the step. . 9. The alignment film is formed by laminating an alignment film material on a portion where a step is generated on the surface and an area around the step using any one of offset printing, spin coating, and ink jet. 10. A method for producing a liquid crystal display element according to 9. In a portion where a step is generated on the surface and a region around the step, alignment is performed by applying any one of linearly polarized light irradiation, rubbing or ion beam irradiation to the stacked alignment film material. The method for producing a liquid crystal display element according to claim 8, wherein a film is formed. The method for manufacturing a liquid crystal display element according to claim 8, wherein the alignment film is formed of an inorganic material in a portion where a step is generated on the surface and a region around the step. The method for manufacturing a liquid crystal display element according to claim 8, wherein the alignment film is formed of a material containing a group IV element alone, a mixture, or a compound in another region of the facing surface. A projection type display device comprising: a light source; a condensing optical system that guides light emitted from the light source to a liquid crystal display element; and a projection optical system that expands and projects light modulated by the liquid crystal display element,
The liquid crystal display element includes a first substrate having an alignment film formed on an opposing surface, a second substrate disposed substantially parallel to the first substrate, the first substrate, and the second substrate. A liquid crystal layer formed between the first substrate and a region where a step is generated on the surface of the facing surface of the first substrate, and another region of the facing surface in a region around the step. A projection type display device comprising a liquid crystal display element in which an alignment film of a type different from the alignment film formed on the substrate is formed.

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