JP3280933B2 - Liquid crystal element and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve contrast, in-screen uniformity and long-term stability with an easy process in a vertical alignment liquid crystal element. SOLUTION: This liquid crystal cell 10 is provided with a first substrate 13, a second substrate 14 and a liquid crystal layer 15 constituted by encapsulating a liquid crystal with negative dielectric anisotropy enclosed between the first and the second substrates. The first substrate 13 has a transparent electrode 17 and is constructed by forming a vertical alignment layer 18 on the transparent electrode 17. The second substrate 14 has a transparent electrode 21 and is constructed by forming a vertical alignment layer 22 on the transparent electrode 21. The alignment layers 18, 22 are subjected to alignment treatment with rubbing and alcohol molecules 25 are absorbed on the surfaces of the alignment layers 18, 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal device and a method for manufacturing the same, and more particularly, to a homeotropic liquid crystal device and a method for manufacturing the same.

[0002]

2. Description of the Related Art FIGS. 8 and 9 show the structure of a general electric field control birefringent liquid crystal display cell. There are two types of electric field control birefringent liquid crystal display cells, a reflection type and a transmission type. Here, a transmission type liquid crystal display cell will be described as an example. FIG.
Shows a state where no voltage is applied, and FIG. 9 shows a state where a voltage is applied.

[0005] The liquid crystal display cell 150 is composed of liquid crystal molecules 15.
This is a so-called homeotropically-aligned liquid crystal cell in which the major axis direction of 7 is almost perpendicular to the electrode surface. As shown in FIG. 8, the liquid crystal display cell 150 includes two transparent glass substrates 151 and 152 that are arranged to face each other at a predetermined interval, and a transparent glass substrate 151 and 152 formed on opposing surfaces of the transparent glass substrates 151 and 152. Electrodes 153 and 154 and transparent electrodes 153 and 154
The alignment films 155 and 156 formed thereon and the alignment film 15
And a liquid crystal layer 158 interposed between the liquid crystal layers 5 and 156. Polarizers 160 and 161 whose polarization directions are orthogonal to each other are arranged above and below the liquid crystal display cell 150.

Next, the operation of the liquid crystal device having the above configuration will be described. When no voltage is applied, the incident light 162 passes through the polarizing plate 161 to become linearly polarized light, and enters the liquid crystal layer 157. Here, in the vicinity of the interface between the two substrates, the liquid crystal molecules are slightly tilted in an appropriate direction by the rubbing treatment on the alignment film (pretilt angle). The incident light linearly polarized by the slight inclination passes through the liquid crystal molecules and becomes slightly elliptically polarized light, and the outgoing light 163 slightly passes through the polarizing plate 160 arranged in a crossed Nicols with respect to the polarizing plate 161.
Becomes This state is a dark display state.

Next, when a voltage exceeding a predetermined threshold voltage is applied between the transparent electrodes 152 and 153, as shown in FIG. 9, the orientation of the liquid crystal molecules 157 is tilted by an electric field to form a predetermined angle. Therefore, the incident light 170 is linearly polarized by the polarizing plate 161, and this linearly polarized light is
When passing through 50, polarized light of a component that is birefringent into two components orthogonal to each other and is parallel to the polarization axis direction of the polarizing plate 160 passes through the polarizing plate 160. This state is a bright display state. At this time, the two polarizing plates 160, 1
High contrast can be obtained by arranging both 61 at about 45 ° with respect to the direction in which the liquid crystal molecules tilt (pretilt direction).

In the above-mentioned liquid crystal device, the following method is used as an alignment treatment for controlling the alignment of liquid crystal.

Generally, an alignment treatment is performed by a rubbing method (hereinafter, referred to as a first conventional example). The rubbing method is a method in which the surface of the alignment film is rubbed with rayon or cotton cloth to give liquid crystal molecules at the interface of the alignment film a pretilt angle.

Another method is disclosed in Japanese Patent Application Laid-Open No. 2-52.
As disclosed in Japanese Patent Publication No.
_{There is} a method of coating a substrate surface by oblique vapor deposition of ₂ , and adsorbing a linear alcohol having 10 or more carbon atoms in the gas phase on the surface (hereinafter, referred to as a second conventional example).

Still another method is disclosed in Japanese Patent Laid-Open No. 60-24447.
As disclosed in Japanese Unexamined Patent Publication (Kokai) No. H10-209, there is a method of treating with a mixture of an alcohol and an amine (hereinafter, referred to as a third conventional example).

[0010]

However, the first to third conventional examples have the following problems.

(1) Problems of the First Conventional Example Since the alignment film surface is physically rubbed to perform the alignment treatment, the inclination angle of the vertical expression group 159 on the surfaces of the alignment films 155 and 156 is reduced as shown in FIGS. It is uneven in the plane. Due to this, unevenness occurs in the outgoing light in the plane when the voltage is applied (for example, as shown in FIG.
70a and 170b are emitted), and display irregularities called rubbing streaks have occurred. Further, since the alignment treatment is performed only by rubbing, the liquid crystal molecules near the substrate interface are slightly inclined from the normal direction of the substrate when no voltage is applied. As a result, slight light leakage occurs, and the black level does not sink sufficiently,
This caused the phenomenon of contrast reduction. This means that, in the case of a reflective element in particular, since light passes through the liquid crystal layer twice, light leakage due to a slight inclination of liquid crystal molecules appears remarkably.

When a material having a large refractive index anisotropy is used (therefore, the cell gap is configured to be small), the cell gap is small, and the cell gap has a tendency to increase the non-uniform orientation over the entire surface. This is larger than a large case (meaning that a material having a small refractive index anisotropy is used), so that light leakage due to slight inclination of liquid crystal molecules becomes remarkable.

(2) Problems of the second conventional example In the second conventional example, the alcohol is adsorbed on the oxide coated on the substrate unless a higher alcohol having a large carbon number is used as the alcohol molecule due to the surface energy. Cannot be used, and inexpensive alcohols having a small number of carbon atoms cannot be used. Further, in order to treat with alcohol vapor, the pressure must be reduced in a vacuum system, and moreover, the alcohol must be heated to vapor, so that a special apparatus is required. Therefore, the manufacturing cost has been high. In addition, oblique deposition of SiO ₂ is difficult to control in practice, and the shape of the oxide or the like on the substrate cannot be changed to a desired shape, and therefore, the orientation of liquid crystal molecules becomes non-uniform. I was (3) Problems of the third conventional example In the third conventional example, a mixture of alcohol and amine (reaction accelerator) is used, so that an amine-based material remains in the device, causing a problem in the reliability of the device. . Further, the heating time requires, for example, about 10 hours, which is not appropriate as an actual manufacturing process.

The present invention solves the above-mentioned problems of the prior art, eliminates light leakage during black display, increases the contrast, improves in-plane uniformity, and has a long-term stability. It is intended to provide a manufacturing method.

Another object of the present invention is to use only an inexpensive and easy-to-use alcohol having 4 or less carbon atoms, do not require a special device such as a vacuum system, and use only an immersion process. It is an object to provide a method for manufacturing a liquid crystal element.

[0016]

In order to achieve the above object, the invention according to claim 1 of the present invention has a pixel electrode.
A vertical alignment film is formed on the pixel electrode;
A first substrate having an alignment film surface subjected to an alignment treatment, and a transparent electrode
A vertical alignment film is formed on the transparent electrode.
A second substrate having the surface of the alignment film subjected to an alignment treatment;
The dielectric anisotropy is negative between the first substrate and the second substrate.
And a liquid crystal layer formed by enclosing a liquid crystal, wherein the vertical alignment film is made of a polyimide resin, and the vertical alignment film of the first substrate.
An alcohol molecule is adsorbed on at least one surface of the vertical alignment film of the second substrate .

As described above, the alcohol molecules adsorb on the surface of the alignment film, so that the alcohol molecules serve to vertically align the liquid crystal molecules. As a result, the present invention has a function of imparting the perpendicularity and directionality to the perpendicular expression group generated by the alignment treatment (rubbing or the like), and further assisting the perpendicularity with the alcohol molecule. Therefore, an ideal homeotropic alignment state in which the pretilt angle is uniform in the plane and substantially 90 degrees and the alignment direction is a fixed direction is obtained. Therefore, a uniform and high-contrast display can be obtained. The term “adsorption” means to include at least one of physical adsorption and chemical adsorption (bonding involving a chemical reaction). Therefore, "alcohol molecules are adsorbed" means that the alcohol molecules are physically adsorbed, chemically adsorbed, or where physical adsorption and chemical adsorption are mixed. It may be in a state. The invention according to claim 2 is the invention according to claim 1.
Liquid crystal element, the vertical expression group generated by the alignment treatment
However, the verticality that attempts to align liquid crystal molecules vertically
Direction in which the liquid crystal molecules are inclined in a predetermined direction and are to be aligned
Alcohol molecules are attached to the liquid crystal molecules,
It is characterized by giving intuition. The invention according to claim 3
Is the liquid crystal element according to claim 1 or 2, wherein
When applied, liquid crystal molecules tilt in the direction of alignment processing
And

The invention according to claim 4 is the invention according to claims 1 to 3.
The liquid crystal device according to any one of the above, wherein a liquid crystal component in the liquid crystal layer is
Having a refractive index anisotropy Δn of 0.07 or more.
And

In the conventional liquid crystal element, when the refractive index anisotropy Δn is increased and the cell gap is reduced, the non-uniformity of the alignment increases throughout the liquid crystal layer.
Cannot be increased. In this regard, in the present invention, since alcohol molecules are adsorbed on the surface of the alignment film, the alignment is uniform. For this reason, it is possible to increase the refractive index anisotropy Δn and reduce the cell gap, thereby achieving a reduction in driving voltage and a reduction in the thickness of the cell.

The invention according to claim 5 is the invention according to claims 1 to 4.
The liquid crystal element according to any one of the above, wherein the electrode has reflectivity.
It is characterized by doing.

In the case of the reflection type liquid crystal element, the light passing through the liquid crystal is modulated by the liquid crystal layer twice, that is, incident and reflection, so that the influence of the non-uniformity of the liquid crystal alignment is larger than that of the transmission type liquid crystal element. . Therefore, the effect of adsorbing alcohol molecules on the surface of the alignment film to achieve an ideal homeotropic alignment state is better than that of the transmission type liquid crystal element according to the second aspect of the present invention. In the reflection type liquid crystal element, it becomes even more remarkable, and a drastic reduction in driving voltage and a thinner cell can be achieved as compared with the conventional reflection type liquid crystal element.

The invention according to claim 6 is the invention according to claims 1 to 5.
The liquid crystal device according to any one of the above, wherein the surface of the alignment film is
Orientation treatment by bing method or photo-alignment method by ultraviolet irradiation
It is characterized by having been done.

The invention according to claim 7 is the invention according to claims 1 to 6.
The liquid crystal device according to any one of the above, further comprising an alcohol molecule
Is an alcohol molecule having 1 to 4 carbon atoms
It is characterized by.

According to the present invention, the electrode is formed on the surface.
Prepare the two insulating substrates thus formed, and attach
And a vertically oriented polyimide resin on the electrode.
Then, this vertical alignment film is formed.
The first substrate and the second substrate
And at least one of the first substrate and the second substrate
Adsorbing alcohol molecules on the surface of the vertical alignment film on one of the substrates;
Are disposed facing each other, and the dielectric constant is anisotropic between the first substrate and the second substrate.
Filling a liquid crystal having a negative property .

With the above configuration, a liquid crystal element having an ideal homeotropic alignment state can be manufactured by a simple method without using a special device or the like.

[0026]

[0027]

The ninth aspect of the present invention provides the liquid according to the eighth aspect.
A method for manufacturing a crystal element, comprising:
Using a rubbing method or a photo-alignment method by ultraviolet irradiation
It is characterized by the following.

The invention according to claim 10 is the invention according to claim 8 or
A method for manufacturing a liquid crystal device according to claim 9,
Alcohols with 1 to 4 carbon atoms as alcohol molecules
Is used.

If the number of carbon atoms of methanol, ethanol, isopropyl alcohol, etc. is 1 to 4, it has a low boiling point, so that unnecessary alcohol can be removed only by drying without a subsequent washing step. Those with more than 1 to 4 carbon atoms
Not very suitable due to high boiling point and high toxicity.

The invention according to claim 11 is the invention according to claims 8 to
10. The method for manufacturing a liquid crystal element according to any one of 10 above,
Alcohol molecules are absorbed on the surface of the alignment film subjected to the alignment treatment.
The step of attaching the surface of the alignment film in an alcohol liquid.
While immersing, the surface of the alignment film is ultrasonically treated in this state.
It is characterized by that.

As described above, by ultrasonic treatment,
The effect of accelerating the reaction between the alignment film and the alcohol molecules and facilitating adsorption is achieved. The invention according to claim 12 is a contract
A method for manufacturing a liquid crystal device according to any one of claims 8 to 11.
Alcohol on the surface of the alignment film after the alignment treatment.
In the step of adsorbing the alcohol molecules, the surface of the alignment film
After immersion in cooling liquid, the alignment film is heated at a temperature of 150 ° C or higher.
It is characterized by heating.

[0033]

1 and 2 are cross-sectional views showing a main structure of a liquid crystal device according to the present invention. FIG. 1 shows a state where no voltage is applied, and FIG. 2 shows a state where a voltage is applied. The liquid crystal element according to the present invention is a transmission type homeotropic liquid crystal element, and basically includes a liquid crystal cell 10 and a polarizer 11 disposed outside one of the liquid crystal cells 10 (the lower side in FIG. 1). And an analyzer 12 arranged outside the other side of the liquid crystal cell 10 (upper side in FIG. 1). The liquid crystal cell 10 includes a first substrate 13, a second substrate 14 arranged to face the first substrate 13, and a liquid crystal layer 15 sealed between the first substrate 13 and the second substrate 14. I have. The first substrate 13 includes a glass substrate 16, a transparent electrode (corresponding to a pixel electrode) 17 made of, for example, ITO formed on the inner surface of the glass substrate 16, and a vertical alignment film 18 formed on the transparent electrode 17. And The second substrate 14 includes a glass substrate 20 and a transparent electrode 21 formed on the inner surface of the glass substrate 20 and made of, for example, ITO.
And a vertical alignment film 22 formed on the transparent electrode 21. The vertical alignment films 18 and 22 are made of, for example, a polyimide resin.

The liquid crystal layer 15 is composed of a liquid crystal having a negative dielectric anisotropy. And the vertical alignment film 1
The alcohol molecules 25 are adsorbed on the surfaces of the liquid crystal layers 8 and 22 in advance, so that the liquid crystal layer 15 has an ideal homeotropic angle in which the pretilt angle is uniform in the plane and substantially 90 degrees, and the alignment direction is constant. It is in a tropic alignment state. As a result, uniform display without display unevenness can be obtained. The reason why an ideal homeotropic alignment state can be obtained by adsorbing alcohol molecules on the alignment film surface will be described later. Note that in this specification, the term “adsorption” means to include at least one of physical adsorption and chemical adsorption (bonding involving a chemical reaction). Therefore, "alcohol molecules are adsorbed" means that the alcohol molecules are physically adsorbed, chemically adsorbed, or where physical adsorption and chemical adsorption are mixed. It may be in a state.

Next, a method of manufacturing the liquid crystal device having the above configuration will be described. First, the transparent electrode 1 is placed on the glass substrate 16.
The first substrate 13 is formed by applying a vertical alignment film 18 on the transparent electrode 17 by spin coating or printing, and performing a heat treatment at an appropriate temperature. Then
An alignment process is performed on the surface of the first substrate 13. Specifically, the alignment film 18 is made of a rubbing cloth such as rayon or cotton.
I rub the surface in a certain direction. Note that, instead of rubbing, alignment treatment may be performed by irradiating ultraviolet rays in an oblique direction.

By such an alignment treatment, the alignment film 18
On the surface, the vertical expression substituent 26 that causes the liquid crystal molecules 24 to be aligned at an angle slightly inclined from the vertical in the alignment direction (for example, 87 degrees from the normal direction) is exposed. These substituents 26
Is oriented in one direction due to rough processing such as rubbing, but various angles are set for the inclination angle. For this reason, in the conventional example, in-plane non-uniformity called rubbing streaks has occurred.

Next, the oriented first substrate 13 is immersed in an alcohol solution such as isopropyl alcohol for several minutes. As a result, the alcohol molecules 25 become
It enters the gap between the substituents 26 on the surface and adsorbs or bonds. Then, since the methyl group and the methylene group of the alcohol molecule 25 have the property of vertically aligning the liquid crystal molecule 24, the surface of the alignment film 18 on the substrate aligns the liquid crystal molecule almost vertically (for example, 89 degrees from the normal direction). (89 degrees of pretilt angle).

Next, the second substrate 14 is replaced with the first substrate 13
It is manufactured by the same method as described above. That is, a transparent electrode 21 is formed on a glass substrate 20, a vertically oriented alignment film 22 is formed on the transparent electrode 21, and the alignment direction of the alignment film 18 is further determined by rubbing or optically aligning the surface of the alignment film 22. An orientation treatment is performed so as to be in the antiparallel direction. Then, the second substrate 14 thus subjected to the alignment treatment is immersed in an alcohol solution, and the alcohol molecules 25 are adsorbed on the surface of the alignment film 22.

Next, the first substrate 13 and the second substrate 14 are arranged to face each other, and a liquid crystal having a negative dielectric anisotropy is filled between the first substrate 13 and the second substrate 14. Thus, the liquid crystal cell 10
Is produced. Then, the polarizer 11 and the analyzer 12 are arranged such that the polarization axis directions of the polarizer 11 and the analyzer 12 are at an angle of 90 °, and at 45 ° with respect to the orientation processing direction. Thus, the transmission type liquid crystal element according to the present invention is manufactured.

In order to adsorb the alcohol molecules on the surface of the alignment film, the substrate may be immersed in a liquid of alcohol and subjected to an ultrasonic treatment or a megasonic treatment. And the reaction of alcohol molecules is accelerated to facilitate adsorption. Furthermore, it may be immersed in a heated alcohol, or may be treated in an alcohol vapor atmosphere. In addition, heating may be performed at a high temperature after the alcohol treatment. In this case, the adsorptive force (coupling force) of the alcohol molecule is increased, and the product can be manufactured more stably. The heating temperature is suitably from 150 ° C to 250 ° C. Incidentally, for reference, in any method of immersion immersion in an alcohol solution, immersion in an alcohol solution + heat treatment after immersion in an alcoholic alcohol solution, the state of adsorption of alcohol molecules on the alignment film surface is as follows. It is considered that physical adsorption and chemical adsorption are mixed. For example,
Even in the above case, there are some that are mainly physically adsorbed but some are chemically adsorbed, and even in the above case, there are also alcohol molecules that are physically adsorbed. It seems that you are doing. However,
The adsorbing force (binding force) of alcohol molecules increases in the order of <<. Therefore, if importance is attached to the adsorption force (coupling force) of alcohol molecules, the above method is preferably used.

Next, the operation of the liquid crystal device having the above configuration will be described. First, the operation when no voltage is applied is shown in FIG.
This will be described with reference to FIG. Incident light 30 from the lower surface of the polarizer 11
When the light is incident, the light passing through the polarizer 11 changes to linearly polarized light and passes through the liquid crystal layer 15. At this time, since the alcohol-treated alignment film surface has been alcohol-treated, the liquid crystal molecules are almost vertically aligned.
The light passing through No. 5 is not modulated at all and proceeds to the analyzer 12 with linearly polarized light, and cannot pass through the analyzer 12 at all, resulting in a very dark black display. Thereby, high contrast can be achieved.

When a voltage is applied, as shown in FIG. 2, since the pretilt angles of the surfaces of the alignment films 18 and 22 are made uniform by the alcohol molecules 25 to approximately 90 degrees, there is no distribution of in-plane tilt angles. The inclination of the liquid crystal molecules 24 is uniform. Thereby, when the incident light 30 is modulated by passing through the liquid crystal layer 15 and passing through the analyzer 12, the
The light 31 emitted from is very uniform in the plane. As a result. A uniform display without any display unevenness can be obtained.

Here, the principle of obtaining an ideal homeotropic alignment state by adsorbing alcohol molecules on the alignment film, which is a main feature of the present invention, will be described in detail below. Conventionally, the alignment treatment was performed by rubbing an alignment film having a vertically expressed substituent, so that the vertically expressed substituent has various tilt angles of several degrees in one direction due to unevenness of the rubbing cloth. Existed.
Therefore, when no voltage is applied, the contrast is lowered due to the slight inclination of the liquid crystal molecules, and when a voltage is applied, display unevenness is caused due to the non-uniformity of the tilt angle. This has caused a problem because the liquid crystal molecules are caused to have both the perpendicularity in which the liquid crystal molecules are vertically oriented and the directionality in which the liquid crystal molecules are oriented in one direction only by the vertical expression substituent.

However, in the present invention, the rubbed vertical expression group 26 has verticality and directionality, and the verticality is assisted by the alcohol molecule 25. In other words, vertical orientation is provided by the alcohol molecule 25, and only the tilting direction is given to the vertical expression group 26 of the rubbed alignment film.

This will be described in more detail with reference to FIG. FIG.
In the above, reference A indicates information on the orientation of the alignment film surface by rubbing (specifically, the inclination angle of the vertically expressed substituent), and reference B indicates the orientation of the liquid crystal layer. The directions of the arrows A and B indicate the orientation directions.
FIG. 3A shows a case of a conventional example in which only rubbing is performed, and each of the regions S1 to S4 of the liquid crystal layer is randomly aligned based on the alignment information A1 to A4.
On the other hand, FIG. 3B shows the case of the present invention,
The randomness of the orientation information A1 to A4 is the alcohol molecule 25
Is considered to be transmitted to the liquid crystal molecules by the above, so that the entire regions S1 to S4 of the liquid crystal layer are uniformly aligned. In addition, a pretilt angle of about 90 degrees can be obtained due to the influence of alcohol molecules.

Therefore, in the present invention, an ideal homeotropic alignment in which the pretilt angle is uniform in the plane, approximately 90 degrees, and the alignment direction is constant is obtained.
Further, since the pretilt angle is very close to 90 degrees, there is also long-term stability against a change in the pretilt angle.

According to the experimental results of the present inventor, the liquid crystal device having the above-mentioned structure can provide a uniform display with a contrast of 2000: 1 or more.

In the above example, both the alignment film 18 of the first substrate and the alignment film 22 of the second substrate adsorb alcohol molecules, but only one of them adsorbs alcohol molecules. Is also good.

In the above example, the transmission type liquid crystal element has been described.
The present invention can be suitably implemented. In particular, when a liquid crystal material having a large refractive index anisotropy Δn of 0.07 to 0.15 is used, the retardation of the tilted liquid crystal on the substrate surface becomes extremely large. The present invention is very effective because the contrast is reduced so much. Hereinafter, a more specific description will be given with reference to FIG.

When the refractive index anisotropy Δn is large, sufficient modulation can be obtained even if the cell gap d is reduced. Therefore, usually, when a material having a large refractive index anisotropy Δn is used for reasons such as a reduction in driving voltage and a reduction in the thickness of the cell, the cell gap d is designed to be small. By the way, when the liquid crystal alignment is non-uniform, generally, when the cell gap d is small, the alignment of the liquid crystal is in an alignment state shown in FIG. 4A, and the non-uniformity of the alignment increases in the plane. Will be. On the other hand, when the cell gap d is large, the orientation state is theoretically as shown in FIG. 4B, and it is considered that the non-uniformity of the orientation increases in the plane as in the case where the cell gap d is small. However, it is known that, in practice, when the cell gap d is large, the influence of the orientation at the interface is reduced at the center of the liquid crystal layer. Therefore, when the cell gap d is large, even if the alignment treatment of the alignment film is not uniform, the effect is relatively small because the entire liquid crystal layer is relaxed. On the other hand, when the cell gap d is small, the effect is large. From such a viewpoint, when the cell gap d is designed to be small using a material having a large refractive index anisotropy Δn, the non-uniformity of the alignment increases in the plane in the conventional alignment processing method. Not suitable for. In this regard, in the present invention, when the cell gap d is designed to be small by using a material having a large refractive index anisotropy Δn, it can be preferably implemented because there is essentially no in-plane non-uniformity. become.

The present invention is also effective for any type of transmissive and reflective direct-view display devices and projection display devices. Although a glass substrate is used for the substrate in the above description, a quartz substrate or a resin substrate may be used for the transmission surface, and a silicon substrate may be used for the substrate on the reflection surface side.

Further, in the case of the transmission type, the electrodes are constituted by using transparent electrodes such as ITO and organic conductive films.
In the reflection type, a reflective pixel electrode such as Al or Ag may be used, or a transparent pixel electrode and a high-reflectance material such as a dielectric mirror may be arranged above the pixel electrode. Good.

[0053]

The present invention will be further described below with reference to specific examples.

(Embodiment 1) Embodiment 1 is an example in which the present invention is applied to an optically addressed spatial light modulator. Hereinafter, FIG.
The manufacturing method will be described with reference to FIG.

(1) As shown in FIG. 5A, an optically polished glass substrate 40 (75 mm × 75 mm × 1.1 m
m), indium tin oxide (hereinafter referred to as ITO) 41 as a transparent conductive film is
Deposit 00Å. Next, 50 Cr was deposited on the surface of ITO41.
0 ° vapor deposition and one side of 18 by photolithography
2783 x 187 with a 24 m pitch
An input light-shielding film 42 made of chromium and formed by an inverted pattern of a pattern in which seven vertical deltas were arranged was formed.

(2) Next, as shown in FIG.
100ppm boron by plasma CVD
The added p-type a-Si: H layer 43 (thickness 500 °), the non-added i-type a-Si: H layer 44 (1.5 μm thickness), and the n-type a-Si: H doped with 1000 ppm of phosphorus. Three layers 45 (thickness 3000 °) were continuously laminated to form a photoconductive layer 46 having a diode structure. Then, Cr was vapor-deposited on the entire surface at 2000 °, and 2783 × 1877 (approximately 52236) squares having a side of 22 μm were formed at a pitch of 24 μm.
(91) Cr pixels 47 arranged in a vertical delta arrangement were produced by photolithography.

(3) Next, as shown in FIG.
The exposed portion of the a-Si: H layer between the pixels is isotropically etched by the chemical dry etching method using a mixed gas of CF ₄ and oxygen, using the square pixels 47 of Cr as a mask at the time of etching. I will do it. And 1.6μ
When the etching is performed for about m times, a groove 48 is dug between the pixels 47 of Cr to form a structure having a Cr eave.

(4) Next, as shown in FIG.
Al is deposited in an amount of 500 to 2,000 by electron beam evaporation.
A film is formed on the entire surface. As a result, a square Al reflective electrode 4 of 500 to 2000
9 are formed, and an output light shielding film 50 of Al is formed at the bottom of the groove 48.

(5) Then, an acrylic resin containing carbon is applied on the Cr pixels 47 by spin coating.
As a result, the resin is buried in the groove 48, and this resin is also deposited on the upper part of the Al reflective electrode 49. Then, the entire surface is etched by a reactive ion etching method using oxygen to remove the resin uniformly over the entire surface.
This etching is finished when the surface of No. 9 appears. As a result, all of the resin on the surface of the Al electrode 49 is removed, but the acrylic resin layer 51 containing carbon remains in the groove (FIG. 6E).

(6) Next, as shown in FIG.
A polyimide film 52 for vertical alignment is formed to a thickness of 200 ° as an alignment film. Similarly, as shown in FIG. 6 (g), a polyimide film 55 for vertical alignment is formed on a glass substrate 54 with an ITO electrode 53, which is a substrate on the opposite side, by 200 [deg.], And both substrates are rubbed using a nylon cloth. Perform processing. The rubbing direction is such that the surface of the polyimide film 52 is 4
Rubbing is performed at an angle of 5 ° so that the opposite side is antiparallel to this direction. Next, the two substrates are immersed in isobutyl alcohol for 5 minutes and dried at 150 ° C. for 1 hour.

(7) Next, a spherical spacer 56 of SiO ₂ having a particle size of 2.0 μm is dispersed on the surface of the polyimide film 55 of the substrate 54 by a wet method, and is bonded to the glass substrate 40 which has been subjected to the above-described processing. The liquid crystal cell thus produced was set in a vacuum injection device, and after reducing the pressure, heated to 120 ° C., and a nematic liquid crystal 57 (manufactured by MERCK JAPAN) having a negative dielectric anisotropy and Δn = 0.08 was injected in vacuum. .

(8) The homeotropic spatial light modulator manufactured as described above is written from the glass substrate 40 side with the writing light 60 and passed through the polarizer 61 arranged parallel or perpendicular to any one side of the pixel. The read light 62 thus obtained was irradiated from the glass substrate 54 side, and the light 63 reflected by the Al electrode 49 was projected as an image through an analyzer 64. When no voltage was applied, there was no leakage light, and the contrast ratio was secured to 2000: 1 or more.

(Embodiment 2) Embodiment 2 is an example in which the present invention is applied to an electric address type spatial light modulation element (normal liquid crystal display element). Hereinafter, the manufacturing method will be described with reference to FIG.

(1) First, as shown in FIG. 7A, an optically polished glass substrate 70 (75 mm × 75 mm × 1.1
1024 × 7 mm by photolithography
68 square Al electrodes 71 are arranged in a square. On the other hand, a glass substrate 72 (75 mm × 75
Indium tin oxide (hereinafter referred to as ITO) 73 is formed as a transparent conductive film to a thickness of 1000 mm by a sputtering method.

(2) Next, alignment films 74 and 75 for vertical alignment are applied to each of the substrates 70 and 72 by spin coating (printing is also possible), and the respective substrates are placed in an anti-parallel direction with a rayon cloth. Rubbed like so. Then, immerse each substrate in isopropyl alcohol for 2 minutes for 1 minute.
Ultrasonic waves of 20 W and 15 kHz were applied. Then, 2.0 μm silica beads 75 are dispersed on the surface of the alignment film 74 of the glass substrate 70 by a wet method, and are adhered with the resin 76 so that the alignment film surfaces of the glass substrate 72 face each other.

Next, the liquid crystal 77 having a negative dielectric anisotropy
Is vacuum-injected into a gap between the glass substrate 70 and the glass substrate 72 to produce a homeotropic liquid crystal cell 78 in which liquid crystal molecules are aligned substantially perpendicular to the substrate.

(3) In a state where the cell 78 is not driven,
Using a polarizing microscope, the polarizer was arranged in parallel with the pixel side and observed under crossed Nicols, and no light leakage was observed.

Next, the polarizing beam splitter 79 was arranged on the glass substrate 72 side, the incident light 80 was input, the reflected light 81 was projected on the screen, and the contrast was measured. As a result, a contrast of 2000: 1 was obtained.

[0069]

As described above, according to the present invention, by causing alcohol molecules to be adsorbed on the surface of the alignment film, vertical alignment of the liquid crystal is provided by the alcohol molecules, and only the direction in which the liquid crystal tilts is rubbed. It can be provided to the vertical development group of the alignment film. Thus, an ideal homeotropic alignment state in which the pretilt angle is uniform in the plane and substantially 90 degrees and the alignment direction is a fixed direction is obtained. Therefore, a uniform and high-contrast display can be obtained.

In order to adsorb alcohol molecules on the surface of the alignment film, it is only necessary to immerse the substrate in an alcohol solution, and a special device is not required, so that the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main configuration of a liquid crystal element according to the present invention when no electric field is applied.

FIG. 2 is a cross-sectional view showing a main configuration of the liquid crystal element according to the present invention when an electric field is applied.

FIG. 3 is a diagram for explaining the principle that the alignment becomes uniform by the adsorption of alcohol molecules on the alignment film surface.

FIG. 4 is a diagram for explaining the relationship between the size of a cell gap and orientation.

FIG. 5 is a sectional view illustrating a manufacturing process of the liquid crystal element according to the first embodiment of the invention.

FIG. 6 is a sectional view illustrating a manufacturing process of the liquid crystal element according to the first embodiment of the invention.

FIG. 7 is a cross-sectional view illustrating a process for manufacturing a liquid crystal element according to Example 2 of the present invention.

FIG. 8 is a cross-sectional view showing a configuration of a main part of a conventional liquid crystal element when no electric field is applied.

FIG. 9 is a cross-sectional view illustrating a configuration of a main part of a conventional liquid crystal element when an electric field is applied.

[Explanation of symbols]

 10: liquid crystal cell 13: first substrate 14: second substrate 15: liquid crystal layer 16, 20, 40, 54, 70, 72: glass substrate 17, 21: transparent electrode 18, 22, 52, 55, 74, 75: Vertical alignment film 24: Liquid crystal molecule 25: Alcohol molecule 26: Vertically expressed substituent

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazunori Komori 1006 Kazuma Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-56-167123 (JP, A) JP-A-62-269117 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1337 520

Claims (12)

(57) [Claims] A pixel electrode having a vertical alignment on the pixel electrode;
Is formed, and the surface of the alignment film is subjected to an alignment treatment.
A first substrate and a transparent electrode, and a vertically oriented alignment film is formed on the transparent electrode.
A second substrate formed and having the alignment film surface subjected to an alignment treatment
And a dielectric anisotropy between the first substrate and the second substrate.
A liquid crystal element comprising a liquid crystal layer in which negative liquid crystal is sealed , wherein the vertical alignment film is made of a polyimide resin, and the vertical alignment film of the first substrate and the second alignment film are made of polyimide resin . Vertical of two substrates
A liquid crystal element, wherein alcohol molecules are adsorbed on at least one surface of the alignment film . 2. The method according to claim 1, wherein the vertical expression group generated by the alignment treatment provides verticality for vertically aligning the liquid crystal molecules and directivity for tilting and orienting the liquid crystal molecules in a predetermined direction. The liquid crystal device according to claim 1, wherein molecules impart the perpendicularity to the liquid crystal molecules. 3. The liquid crystal device according to claim 1, wherein, when an electric field is applied, the liquid crystal molecules are inclined in the direction of the alignment treatment. 4. The liquid crystal element according to claim 1, wherein the refractive index anisotropy Δn of the liquid crystal molecules in the liquid crystal layer is 0.07 or more. 5. The liquid crystal device according to claim 1, wherein the electrode has reflectivity. 6. The liquid crystal device according to claim 1, wherein the surface of the alignment film is subjected to an alignment treatment by a rubbing method or a photo alignment method by irradiation with ultraviolet rays. 7. The liquid crystal device according to claim 1, wherein the alcohol molecule is an alcohol molecule having 1 to 4 carbon atoms. 8. Two insulating substrates having electrodes formed on the surface.
Are prepared, and each insulating substrate is vertically arranged on the electrode.
An orientation film made of a directional polyimide resin is formed , and then
By subjecting the vertical alignment film to an alignment treatment,
Forming a first substrate and a second substrate; and forming at least one of the first substrate and the second substrate.
Adsorbing alcohol molecules on the surface of the vertical alignment film of the plate, and disposing the first substrate and the second substrate to face each other,
Liquid crystal with negative dielectric anisotropy between the substrate and the second substrate
And a method of manufacturing a liquid crystal element. 9. The method for manufacturing a liquid crystal device according to claim 8, wherein a rubbing method or a photo-alignment method by ultraviolet irradiation is used as the alignment treatment of the alignment film. 10. The method for manufacturing a liquid crystal device according to claim 8, wherein the alcohol molecule is
A method for manufacturing a liquid crystal element, wherein an alcohol having 1 to 4 carbon atoms is used. 11. The step of adsorbing alcohol molecules on the surface of the alignment film subjected to the alignment treatment is characterized in that the surface of the alignment film is immersed in an alcohol liquid and the surface of the alignment film is subjected to ultrasonic treatment in that state. Claims 8 to 10
The method for producing a liquid crystal element according to any one of the above. 12. The method of adsorbing alcohol molecules on the surface of the alignment film subjected to the alignment treatment, wherein the alignment film surface is immersed in an alcohol liquid, and then the alignment film is heated at a temperature of 150 ° C. or higher. A method for manufacturing a liquid crystal element according to claim 8.