JP2000180864A - Liquid crystal element and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal element for suppressing an image defect from being generated or an image quality from getting adverse. SOLUTION: A first lock member 10 is supported on the side of one glass substrate 1a, a second lock member 11 is supported on the side of another glass substrate 1b, and these lock members 10 and 11 are adhered mutually at side face vertical to the substrates 1a and 1b. Most of parts of lock members 10 and 11 are arranged in a non-pixel area. Thus, even when an alignment defect is generated by these lock members 10 and 11, since most of alignment defects generate in the non-pixel area, the recognition as the image defect is reduced and as a result, the generation of the image defect can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device for displaying various images by using a liquid crystal, and a method for manufacturing the liquid crystal device.

[0002]

2. Description of the Related Art Conventionally, a CRT has been known as a display device for displaying an image, and has been most widely used for various purposes such as displaying a moving image of a TV image or a VTR image and a monitor of a personal computer.

[0003] However, this CRT has the following disadvantages. * When displaying a still image, scanning fringes and the like are visually recognized due to flicker and lack of resolution, resulting in poor image quality. Deterioration of fluorescent lamps due to burn-in * Electromagnetic waves may have an adverse effect on the human body (eg, harm the health of VDT workers) * Requires a large space behind the screen, office or home There is a problem in that it hinders space savings.

[0004] A liquid crystal panel (liquid crystal element) is known as a display device which solves such a problem of the CRT, and one of them is a twisted nematic (Twisted N).
(TN) A liquid crystal using a liquid crystal (TN) liquid crystal is known (“Applie” by M. Schadt and W. Helfrich).
d Physics Letters Volume 18, Volume 4
No. (issued February 15, 1971) pages 127-128
Page ”).

There are two types of liquid crystal panels using the TN liquid crystal: a simple matrix type and a TFT type (where a transistor is arranged in each pixel as is well known). Has disadvantages. That is, the former can be manufactured at a low cost and has an advantage in terms of cost, but has the disadvantage that crosstalk occurs during time-division driving when the pixel density is increased (in other words, the crosstalk is reduced). The disadvantage is that the pixel density cannot be increased so much to avoid this. In the latter, the problem of crosstalk is solved and the problem of response speed is solved by the transistor. On the other hand, it is difficult to mass-produce a large-area liquid crystal panel because defective pixels are likely to be generated. In this case, there is a disadvantage that the manufacturing cost is increased due to a decrease in the manufacturing yield and the like.

As a TN liquid crystal panel which does not have the above-mentioned drawbacks, a liquid crystal panel of a type which controls transmitted light by combining with a polarizing element utilizing the refractive index anisotropy of liquid crystal molecules exhibiting ferroelectricity ( Hereinafter, a "ferroelectric liquid crystal panel" is proposed by Clark and Lagerwall (JP-A-56-107216, U.S. Pat. No. 436).
No. 7924).

This liquid crystal (hereinafter referred to as “ferroelectric liquid crystal”) generally has a chiral smectic C phase (SmC *) or an H phase (SmH *) in a specific temperature range, and is added in this state. Taking one of a first optically stable state and a second optically stable state in response to an electric field;
And the property of maintaining the state when no electric field is applied,
In other words, it has bistable memory properties, and exhibits a very fast response speed because of inversion switching by spontaneous polarization, and also has excellent viewing angle characteristics,
It is suitable as a high-speed, high-definition, large-screen display device.

Further, the above-described ferroelectric liquid crystal panel has
In the initial alignment stage, the liquid crystal molecules aligned in the first stable state and the liquid crystal molecules aligned in the second stable state are mixed in the domain. That is, in the chiral smectic liquid crystal in the bistable state, the alignment controlling force for aligning the liquid crystal molecules in the first stable state and the alignment controlling force for aligning the liquid crystal molecules in the second stable state have substantially equal energy levels. When the chiral smectic liquid crystal is aligned under the state of the alignment film thickness thin enough to exhibit bistability, the liquid crystal molecules aligned in the first stable state and the second stable state in the domain are initially aligned. It will be mixed at the stage.

As a technique for constructing a liquid crystal panel using similar refractive index anisotropy and spontaneous polarization of liquid crystal molecules, a liquid crystal exhibiting antiferroelectricity (hereinafter referred to as "antiferroelectric liquid crystal"). The use of is known. This antiferroelectric liquid crystal generally has a chiral smectic CA phase (SmCA *) in a specific temperature range. In this state, when no electric field is applied, the average optical stable state is in the normal direction of the smectic layer. Accordingly, an average optical stable state is inclined from the layer normal direction. In addition, the antiferroelectric liquid crystal also performs switching by coupling of spontaneous polarization and electric field, so that it exhibits a very fast response speed and is expected to be used for a high-speed liquid crystal panel.

As shown in FIG. 1, a liquid crystal panel as described above is formed on a pair of glass substrates 1a and 1b arranged in parallel with a predetermined gap therebetween, and formed on these glass substrates 1a and 1b. And a liquid crystal 3 sandwiched between a pair of glass substrates 1a and 1b (hereinafter, referred to as a "substrate gap"), between the transparent electrodes 2a and 2b. It is driven by applying a voltage equal to or higher than a certain threshold. Note that reference numerals 4a,
Reference numeral 4b denotes an alignment film formed so as to cover the transparent electrodes 2a and 2b, and reference numeral 5 denotes a color filter. Also,
Reference numeral 6 indicates a flattening film of the color filter, and reference numeral 7
Indicates a spacer (to be described in detail later) for defining a substrate gap.

[0011] However, in such a liquid crystal panel P _1, the substrate gap is not uniform in all parts screen, the electric field applied to the liquid crystal 3 becomes not uniform, image quality image unevenness occurs and There was a problem of getting worse. In particular, in the case of a liquid crystal panel using a ferroelectric liquid crystal (FLC) or an antiferroelectric liquid crystal (A-FLC), it is necessary to narrow the substrate gap (about 1 to 3 μm). Even a small degree of non-uniformity will greatly affect image quality.

[0012]

By the way, in order to make the gap between the substrates uniform and to avoid the above-mentioned problem, a spacer is arranged in the gap between the substrates so that the gap between the substrates is not narrowed. It is necessary to bond both substrates so that the gap between the substrates is not widened by disposing an adhesive. Such a spacer, an adhesive and a method of disposing them in the gap between the substrates are as follows. B. A method in which both the spacer and the adhesive are in the form of spherical fine particles, a large number of fine-particle spacers and a fine-particle adhesive are sprayed on the substrate, and then the two substrates are bonded to each other; For example, a stripe-shaped spacer denoted by reference numeral 7 in FIGS. 1 and 2 is arranged in the gap between the substrates by using a flexographic printing method and a photolithography method, or by sticking a dry film-shaped spacer. There is a method for both defining the substrate gap and bonding the two substrates 1a and 1b, but both have problems.

That is, in the case of the above A, since the spacers and the adhesives are scattered and arranged, it is impossible to select (control) the arrangement place, and the pixel area (refer to the symbol D in FIGS. 1 and 2). ) / These pixels are arranged regardless of the non-pixel area (see reference numeral C in FIGS. 1 and 2). However, alignment defects occur around the area where these spacers and adhesives are disposed, and the alignment defects generated in the pixel region become image defects, and image defects such as insufficient contrast can be obtained. There was a problem that causes.

On the other hand, in the case of the above B, since the spacer 7 is formed by a photolithography method or by sticking a dry film, the spacer 7 is formed only in the non-pixel region C. It is possible to select (control) the arrangement location, prevent the occurrence of alignment defects in the pixel region D, and suppress the occurrence of image defects. However, such a spacer 7 is used by bonding the upper and lower surfaces (of the spacer 7) to the substrates 1a and 1b, respectively. However, such bonding alone results in a weak adhesive force between the two substrates 1a and 1b, thereby reducing the liquid crystal panel. Adhesion between the substrates 1a and 1b and the spacer 7 when manufacturing (for example, injecting the liquid crystal 3 into the gap between the substrates) or when using the liquid crystal panel (when dropping the liquid crystal panel on the floor, etc.) However, there has been a problem that a uniform gap cannot be maintained.

[0015] The present inventors have actually created a liquid crystal panel P ₁ shown in FIGS. 1 and 2, 5 of the static pressure load test (liquid crystal panel
A test was conducted in which a weight was placed on a circular portion of 0 mmφ to observe the occurrence of image defects) and a drop impact test (a test in which a liquid crystal panel was dropped into a drop impact tester) to confirm the impact resistance. The spacer 7 was formed in a stripe shape having a width of 30 μm, and the repetition pitch was set to 300 μm. Other configurations and manufacturing methods were the same as in Example 1 described later.

In the above-described static pressure load test, it was found that an image defect occurred only by applying a load of 10 kg, and in a drop impact test, an image defect occurred at 80 G or more.

Accordingly, an object of the present invention is to provide a liquid crystal element which suppresses occurrence of image defects and deterioration of image quality.

Another object of the present invention is to provide a liquid crystal element having improved impact resistance.

Still another object of the present invention is to provide a method for manufacturing a liquid crystal element for manufacturing the above-described liquid crystal element.

[0020]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes a pair of substrates arranged in parallel with a predetermined gap therebetween, and a pair of substrates arranged in a gap between the pair of substrates. In the liquid crystal device including the liquid crystal and the electrode supported by the substrate, one of the pair of substrates supports a plurality of first locking members, and the other substrate includes A plurality of second locking members locked by the first locking member are supported, and the first locking member and the second locking member are bonded to each other.

In this case, the first locking member and the second locking member
Preferably, all or most of the locking member is arranged in the non-pixel region.

On the other hand, the present invention provides a liquid crystal device comprising a step of forming electrodes on each of a pair of substrates, a step of bonding the pair of substrates, and a step of injecting a liquid crystal into a gap between the pair of substrates. Forming a plurality of first locking members on one of the pair of substrates before locking the substrates, and locking the first locking members on each of the other substrates. Forming a plurality of second locking members at such positions as described above, and bonding the pair of substrates so that these locking members are fitted together and bonded. To be performed.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An embodiment of the present invention will be described.

First, the structure of the liquid crystal device according to the present invention will be described with reference to FIGS. Here, FIG.
FIG. 4 is a sectional view showing an example of the structure of a liquid crystal element according to the present invention, and FIG. 4 is a plan view thereof. FIG. 5 is a plan view showing another example of the structure of the liquid crystal element according to the present invention, and FIG. 6 is a cross-sectional view showing a manufacturing process of the liquid crystal element shown in FIG.

As shown in FIG. 3, for example, a liquid crystal element according to the present invention has a pair of substrates 1a and 1b which are arranged in parallel with a predetermined gap therebetween, and is disposed in a gap between the pair of substrates 1a and 1b. Liquid crystal 3 and electrodes 2a and 2b supported on the substrates 1a and 1b.

The first locking member 1 is provided on one of the substrates 1a.
Are supported, and a plurality of second locking members 11 that are locked to the first locking member 10 are supported on the other substrate 1b. The two locking members 11 are bonded to each other.

In this case, as shown by reference numerals 10 and 11 in FIG. 4 and by reference numerals 20 and 21 in FIG. 5, all or most of the first locking member and the second locking member are formed in the non-pixel region C. (That is, a region in which the liquid crystal 3 is not switched or does not contribute to image formation even if the liquid crystal 3 is switched. A region D other than the non-pixel region C, that is, the electrodes 2a and 2b are A region where the liquid crystal 3 is switched by applying a voltage to the liquid crystal 3 via the interface and thereby contributes to the formation of an image is referred to as a pixel region D (the same applies in the present specification).

Further, as shown in FIG.
At least two first locking surfaces 10a, 10b are formed on each of the locking members 10, and the first locking surfaces 10a, 1 are formed on each of the plurality of second locking members 11.
0b, at least two second locking surfaces 11a and 11b are formed, and the first locking surface 10a and the second locking surface 11a and the first locking surface 10b and the second locking surface opposing each other are formed. Face 1
1b may be bonded.

In the liquid crystal element according to the present invention, the first locking member 10 and the second locking member 11 define a substrate gap. As a method, as shown in FIG.
The insertion point of the locking member 10 (that is, the second locking surface 11
a, 11b), the substrate 1b is exposed, the projecting height of the first locking member 10 is set to be substantially equal to the substrate gap, and the distal end surface of the first locking member 10 is set to the other substrate. 1b to define the substrate gap by abutting against the side of 1b, the projecting height of the second locking member 11 is set substantially equal to the substrate gap, and the tip end surface of the second locking member 11 is set to the one substrate. A method of defining a substrate gap by abutting against the side of the first locking member 1a; setting both the projecting heights of the first locking member 10 and the second locking member 11 substantially equal to the substrate gap; A method of defining the substrate gap by abutting the distal end surface of the stop member 10 against the other substrate 1b and the distal end surface of the second locking member 11 against the one substrate 1a, etc. be able to.

Note that an insulating film (not shown) and alignment films 4a and 4b may be formed so as to cover the electrodes 2a and 2b.

Here, the liquid crystal 3 may be a chiral smectic liquid crystal such as a ferroelectric liquid crystal or an antiferroelectric liquid crystal driven by utilizing the action of spontaneous polarization. An acrylic photosensitive resin may be used for the second locking member 11.

Next, a method for manufacturing a liquid crystal element according to the present invention will be described.

First, electrodes 2a and 2b are formed on a pair of substrates 1a and 1b, respectively. In this case, the electrodes 2a,
An insulating film or alignment films 4a and 4b may be formed so as to cover 2b. When a liquid crystal element for color display is formed, a color filter 5 may be formed.

Next, the first locking member 1 is attached to one of the substrates 1a.
0 and a plurality of first locking members 10 on the other substrate 1b.
The plurality of second locking members 11 are formed at positions where the second locking members 11 are locked. Such a first locking member 10 and a second locking member 1
As a method for forming the substrate 1, a material which is cured by applying light or heat and which is not cured is used as the substrate 1 a,
A method in which the material is applied to the surface of 1b by a printing method or the like, the material is cured, and then patterned by a photolithography method.

Thereafter, the pair of substrates 1a and 1b are bonded together so that the first locking member 10 and the second locking member 11 are fitted and bonded to each other (see FIG. 6).
As a result, the pair of substrates 1a and 1b are arranged in parallel, and the substrate gap is defined by the first locking member 10
And the second locking member 11.

Further, a liquid crystal 3 is injected into a gap between the pair of substrates 1a and 1b.

Next, the effect of this embodiment will be described.

According to the present embodiment, the first locking member 1
Since all or almost all of the 0 and 20 and the second locking members 11 and 21 are arranged in the non-pixel region C, the occurrence of alignment defects and the generation of image defects in the pixel region D can be suppressed.

Since the first locking members 10 and 20 and the second locking members 11 and 21 are bonded to each other, the bonding strength between the two substrates 1a and 1b is improved as compared with the conventional one. . Therefore, when the liquid crystal 3 is injected into the gap between the substrates,
Even when the liquid crystal element is dropped on the floor, a uniform substrate gap can be maintained, and deterioration of image quality can be prevented.

Further, at least two first locking surfaces 10a and 10b are formed on each first locking member 10, and
At least two second locking surfaces 11a and 11b are formed on each second locking member 11 so as to face the first locking surfaces 10a and 10b, and the first locking surfaces 10a and 10b facing each other are formed.
When the liquid crystal element is dropped, the substrate 1a is bonded to the second locking surface 11a, 11b.
Relative displacement between the substrate and the substrate 1b in the plane direction can be reduced, and the shock resistance of the liquid crystal element can be improved.

[0041]

The present invention will be described below in more detail with reference to examples.

[0042] Example 1 In this Example, was prepared a liquid crystal panel (liquid crystal device) P ₂ shown in FIGS.

A glass substrate having a thickness of 1.1 mm was used for the substrates 1a and 1b.

A transparent electrode made of ITO (indium tin oxide) is used for the electrodes 2a and 2b.
A large number of the transparent electrodes 2a and 2b were formed in stripes on the surfaces of the two glass substrates 1a and 1b.

Further, alignment films 4a and 4b were arranged so as to cover the transparent electrodes 2a and 2b. These alignment films 4a, 4b
Was formed with a polyimide film (trade name: LQ-1800, manufactured by Hitachi Chemical Co., Ltd.).

The first locking member 10 and the second locking member 11 are made of an acrylic photosensitive material (product name: JNPC-43, manufactured by Nippon Synthetic Rubber Co.) on the surface of each of the alignment films 4a and 4b. Formed. Here, as shown in FIG. 4, a large number of the first locking members 10 were arranged in a stripe shape so as to be parallel to each other, the width of the formation was 10 μm, and the pitch was 300 μm. Further, the second locking member 11 has a thickness of 10 μm.
The first locking member 10 is fitted with two stripes (each having a width of 10 μm and a gap of 10 μm) arranged close to each other with a gap of m. I made it. The pitch of the second locking member 11 is the first
Like the locking member 10, the thickness was 300 μm.

Further, the liquid crystal 3 includes a ferroelectric liquid crystal (CS1).
014, manufactured by Chisso Corporation).

[0048] Next, a method for manufacturing the liquid crystal panel P _2.

First, an ITO film is formed to a thickness of 700 ° on each surface of the glass substrates 1a and 1b by sputtering, and the ITO film is patterned into stripes by photolithography to form transparent electrodes 2a and 2b. Was formed.

Next, the above-mentioned polyimide film is formed by flexographic printing so as to cover the transparent electrodes 2a and 2b, and baked at a temperature of 300 ° C. for 1 hour using a clean oven to form the alignment films 4a and 4b. Formed.

Then, the above-mentioned acrylic photosensitive material is spin-coated on the surfaces of the alignment films 4a and 4b, * pre-baked for 180 sec at a temperature of 80 to 90 ° C., * cooled to room temperature, * UV irradiation using an exposure mask (however, irradiation energy is 250 mJ / cm ²
(＠ 365 nm)) * Developing for 30 sec with a dedicated alkaline developer (CD-902 / N-methylpyroperidine 1% aqueous solution), * Rinse using pure water, * Post-bake using a clean oven (200
The first locking member 10 and the second locking member 11 were formed in this order.

Next, using a rubbing cloth made of cotton cloth, the surfaces of the respective alignment films 4a and 4b (exactly, the first locking member 10 and the second locking member 11 are not formed and are exposed. Rubbing treatment was performed on the portions of the alignment films 4a and 4b where they exist.

Then, the transparent electrodes 2a, 2
The two glass substrates 1a and 1b formed with b and the like were bonded so that the rubbing directions became parallel and the first locking member 10 and the second locking member 11 were fitted. At this time, the side surfaces 10a and 10b of the first locking member 10 and the side surfaces 11a and 11b of the second locking member 11 were bonded. Thus, a liquid crystal cell having a substrate gap of 1.0 μm was prepared.

Next, create a liquid crystal panel P ₂ by injecting the ferroelectric liquid crystal 3 to the substrate gap of the liquid crystal cell.

[0055] Thereafter, pasting and polarizing plate (not shown) to the outer surface of the liquid crystal panel P _2, we implemented the Dr-IC (not shown).

Next, the effect of this embodiment will be described.

[0057] Image defects in the liquid crystal panel P ₂ were prepared in this Example was hardly generated.

Also, the impact resistance of the liquid crystal panel is improved,
Even in the static pressure load test, even when a weight of 20 kg or less was placed on the 50 mmφ circular portion, no image defect (the generation of an alignment defect in the pixel region D) was observed. Further, when a drop impact test (that is, a test in which a liquid crystal panel was put into a drop impact tester and dropped) was performed, no image defect was generated (the generation of an alignment defect in the pixel region D) was observed up to 100G.

[0059] In Example 2 This example was prepared a liquid crystal panel (liquid crystal device) P ₃ shown in FIG.

However, the pixel region D was formed into a square shape of 30 μm square, and the non-pixel region C was formed into a lattice shape having a width of 10 μm.

The first locking member 20 is formed in a cross shape between four adjacent pixel regions D, has a width of 10 μm, and has a repetition pitch of 300 μm. In addition, the second locking member 21 has a rectangular column shape of 10 μm square, and is arranged at four corners of each pixel region D. The repetition pitch of the first locking member 20 is 300 μm.
m.

The other structure and manufacturing method were the same as those in the first embodiment.

Next, the effect of this embodiment will be described.

According to this embodiment, substantially the same effects as those of the first embodiment were obtained. The maximum load at which no image defect was generated in the static pressure load test was 18 kg, and no image defect was generated at 100 G or less in the drop impact test.

[0065]

As described above, according to the present invention,
Since the first locking member and the second locking member are bonded to each other, the adhesive strength between the two substrates is improved as compared with the conventional one. Therefore, even when the liquid crystal is injected into the gap between the substrates or when the liquid crystal element is dropped on the floor, the uniform gap between the substrates can be maintained, and the deterioration of the image quality can be prevented.

When all or most of the first locking member and the second locking member are arranged in the non-pixel region, the occurrence of alignment defects and image defects in the pixel region can be suppressed.

Further, at least two first locking surfaces are formed on each first locking member, and a second locking surface facing the first locking surface is formed on each second locking member. When at least two of the substrates are formed and the opposing first locking surfaces are adhered to each other, even when the liquid crystal element is dropped, the relative displacement of the two substrates in the surface direction can be reduced, and the resistance of the liquid crystal element can be reduced. The impact property can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of a conventional liquid crystal panel.

FIG. 2 is a plan view of FIG. 1;

FIG. 3 is a sectional view showing an example of the structure of a liquid crystal panel (liquid crystal element) according to the present invention.

FIG. 4 is a plan view of FIG. 3;

FIG. 5 is a plan view showing another example of the structure of the liquid crystal panel according to the present invention.

FIG. 6 is a sectional view showing a manufacturing process of the liquid crystal panel shown in FIG. 3;

[Explanation of symbols]

1a, 1b Glass substrate (substrate) 2a, 2b Transparent electrode (electrode) 3 Ferroelectric liquid crystal (liquid crystal) 10 First locking member 10a, 10b First locking surface 11 Second locking member 11a, 11b Second member Stop surface C Non-pixel area D Pixel area P ₂ liquid crystal panel (liquid crystal element) P ₃ liquid crystal panel (liquid crystal element)

Claims (10)

[Claims] 1. A liquid crystal device comprising: a pair of substrates disposed in parallel with a predetermined gap therebetween; a liquid crystal disposed in a gap between the pair of substrates; and an electrode supported by the substrate. A plurality of first locking members are supported on one substrate of the pair of substrates, and a plurality of second locking members locked on the first locking member are supported on the other substrate. And the first locking member and the second locking member are bonded to each other. 2. The liquid crystal device according to claim 1, wherein all or most of the first locking member and the second locking member are arranged in a non-pixel region. 3. At least two first locking surfaces are formed on each of the plurality of first locking members, and each of the plurality of second locking members faces the first locking surface. The at least two such second locking surfaces are formed, and the opposing first locking surface and the second locking surface are bonded to each other. Liquid crystal element. 4. The substrate gap according to claim 1, wherein a substrate gap is defined by abutting a tip end surface of the first locking member against the other substrate. Liquid crystal element. 5. The substrate gap according to claim 1, wherein a substrate gap is defined by abutting a distal end surface of the second locking member against the one substrate. Liquid crystal element. 6. A substrate gap is defined by abutting a distal end surface of said first locking member against said other substrate and abutting a distal end surface of said second locking member against said one substrate. The liquid crystal device according to any one of claims 1 to 3, wherein 7. The liquid crystal device according to claim 1, wherein the liquid crystal is a chiral smectic liquid crystal. 8. The liquid crystal according to claim 1, wherein the first locking member and the second locking member are formed using an acrylic photosensitive resin. element. 9. A method for manufacturing a liquid crystal element, comprising: a step of forming electrodes on each of a pair of substrates; a step of bonding the pair of substrates; and a step of injecting liquid crystal into a gap between the pair of substrates. A step of forming a plurality of first locking members on one of the pair of substrates before the step of bonding the substrates, and a step of locking the first locking members on each of the other substrates. Forming a plurality of second locking members at the positions,
And bonding the pair of substrates so that the locking members are fitted together and adhered to each other. 10. The formation of the first locking member and the second locking member by applying a material before curing to the surface of the substrate, curing the material, and further patterning the material. The method for manufacturing a liquid crystal element according to claim 9, wherein: