JP2000111884A - Liquid crystal panel frame and liquid crystal panel body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal panel body which has a uniform and stable alignment as a whole and obtains high contrast by solving problems of generation of crack and unevenness of density. SOLUTION: The liquid crystal panel frame has plural linear partition members 404 provided between both substrates and arranged in parallel with each other with a specified interval and alignment films 403 subjected to uniaxial aligning treatment. The plural linear partition members 404 are extended almost in parallel with respect to a direction of the uniaxial aligning treatment. Further, either ferroelectric or antiferroelectric liquid crystal is enclosed in the liquid crystal panel frame, in which parts, except for opening edge parts for passage of liquid crystal formed on edges of the plural linear partition members 404, form respective linear spaces in the state closed toward liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display as an information display terminal for home business. More specifically, the present invention relates to a technique for controlling the orientation of a liquid crystal display using a smectic layer such as a ferroelectric liquid crystal or an antiferroelectric liquid crystal.

[0002]

2. Description of the Related Art Liquid crystal displays are becoming more and more popular as flat panel displays because of their advantages such as light weight, space saving and low power consumption. It is expected as a replacement.

Above all, ferroelectric and antiferroelectric liquid crystals can be driven by a simple matrix because of their high-speed response, high viewing angle, and memory properties. However, with respect to the orientation, zigzag defects and linear defects characteristic of the smectic layer occur, and it is hard to say that the display quality is sufficient. Furthermore, since a semi-solid smectic phase is used, unlike a liquid nematic liquid crystal, if the layer structure of the liquid crystal is broken once by deformation of the liquid crystal panel body, there is no self-healing property and it cannot be used continuously. There was a fatal drawback.

As means for solving these two problems at the same time, a pair of glass substrates is completely adhered via a linear partition member, these liquid crystals are sealed in a linear space formed, and a temperature gradient cooling method is used. The present inventors have disclosed a technique for improving the alignment state of the liquid crystal by using the method described in Japanese Patent Application Laid-Open No.
-318912, JP-A-7-159792, etc.).

In this method, the liquid crystal panel frame is formed as shown in FIG.
As shown in FIG. 3, an electrode 102 is formed on at least one of a pair of substrates 101 and an alignment film 103 for controlling alignment is formed thereon.
Is formed, and the linear partition member 104 is formed as a spacer by a standard photolithography method. The width of the partition member 104 is selected in the range of about 5 to 30 microns, which is about the width between electrodes, and the thickness is almost the same as the cell gap, and is set to a desired value in the range of 1 to 2 microns. The pitch is 30 to 3 at the electrode pitch or multiple pitches
It is about 00 microns. By bonding the upper and lower substrates by heat and pressure via such a partition member 104, an elongated linear space that is substantially closed except at the opening end is obtained, and the liquid crystal 105 is sealed and held therein. The alignment film 103 is rubbed in a direction substantially parallel to the partition wall.
It has uniaxial orientation such as UV irradiation, and the uniaxial orientation may be imparted by an obliquely deposited silicon dioxide film in addition to the organic orientation film.

A smectic liquid crystal is sealed in a liquid state or a cholesteric phase in a liquid crystal panel frame having this structure, and a temperature gradient cooling is performed to gradually move the liquid crystal panel from a high temperature constant temperature bath to a room temperature constant temperature bath. The moving direction is substantially parallel to the partition walls, whereby a temperature gradient is generated in each linear space as shown in FIG. 2, and the liquid crystal inside is cooled sequentially from one end of the space to the other end. . Due to the temperature gradient cooling, the volume shrinkage of the liquid crystal occurs sequentially from the low temperature side, and the flow of the liquid crystal in a certain direction is thereby induced. By doing so, the orientation of the smectic A phase is improved, and as a result, a chiral smectic phase free of zigzag defects and linear defects is formed.

In order to induce effective liquid crystal flow in the smectic A phase in this temperature gradient cooling method, it is necessary to make the sectional area of the elongated space surrounded by the partition member and the upper and lower substrates smaller than a certain critical value. is there. For this purpose, the pitch of the partition member is optimized, not the cell gap which cannot be largely changed. This value is about 800 microns or less.

[0008] Regarding the temperature gradient, the smectic A phase needs to be at least 2 ° C per mm. In an antiferroelectric liquid crystal having no cholesteric phase, a desirable temperature gradient is 4 ° C. or more per 1 mm. There are two methods for applying a temperature gradient.
The liquid crystal panel is moved between thermostats of different temperature atmospheres, and the thermostat is selected from liquid, solid, and gas. Such a strong temperature gradient can be applied only to the above-mentioned adhesive liquid crystal panel body. If not adhered, the glass substrate shrinks sharply, the liquid crystal is rubbed on the glass surface, and the smectic layer becomes sandy, so that a desirable alignment state cannot be obtained.

As described above, the adhesive type panel having the partition member is used for the temperature gradient cooling method. This can solve not only the problem of controlling the alignment of the smectic liquid crystal but also the problem of impact resistance. Due to the partition member, the liquid crystal panel body becomes robust and can withstand a pressing impact up to about 100 N / cm ² . Yet another advantage is that the cell gap can be controlled with very high precision by the partition walls. Still another advantage is that since the liquid crystal is partitioned by the partition walls, the direction of permeation of the liquid crystal is linearly restricted and does not meander.

The combined use of the above-mentioned adhesive panel with the partition member and the temperature gradient cooling method not only significantly improves the impact resistance of the liquid crystal panel body, but also provides a substantially defect-free alignment layer for the ferroelectric liquid crystal. Can be manufactured stably. An unprecedented orientation can be obtained even with an antiferroelectric liquid crystal.

[0011]

However, when the uniaxial orientation treatment is nearly parallel to the direction in which the partition walls extend (see FIG. 3), the direction parallel to the partition walls, that is, the liquid crystal layer normal direction 301 during panel cooling or temperature gradient cooling. Liquid crystal crack 302
(Cracks) may occur.
This problem occurs when the partition pitch is about 250 μm or less. This is because the in-layer direction 30 with a large shrinkage
It is considered that, by limiting the distance of 3 short, the volume contraction of the liquid crystal cannot be accommodated in the layer. In the liquid crystal having the layer structure used here, the flow of the liquid crystal is less likely to occur between the layers than in the layer, so that the movement between the layers can occur only to a certain extent. The density change that could not be compensated for by the interlayer movement must be covered within the layer, but if the distance in the layer direction is limited to a short distance by the partition, this cannot be achieved, and cracks are considered to occur. That is, it can be said that the cause of the crack generation is insufficient of the filling density of the liquid crystal.

In addition to the problem of cracks, when the filling of liquid crystal is not at a high density, there is a problem that the density is non-uniform in the panel and the display becomes uneven.

The present invention solves the above-mentioned problems of crack generation and non-uniform density, and has a liquid crystal panel frame and a liquid crystal having uniform and stable orientation as a whole and capable of obtaining a high contrast ratio. It is intended to provide a panel body.

[0014]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a first aspect of the present invention, in which at least one of a pair of transparent substrates and a pair of transparent substrates formed on those substrates are provided. A pair of electrodes facing each other, a plurality of linear partition members provided between the two substrates and arranged in parallel at a predetermined interval, and formed on at least one of the pair of substrates. A plurality of linear partition members extending substantially parallel to the direction of the uniaxial alignment process, and further comprising a plurality of linear partition members. The liquid crystal panel frame is characterized in that a part other than the liquid crystal passing opening end formed at one end of the liquid crystal panel forms a linear space sealed with respect to the liquid.

According to a second aspect of the present invention, based on the first aspect of the present invention, the plurality of linear partition members are 20 to 20.
A liquid crystal panel frame characterized by being arranged at an interval of 800 μm.

According to a third aspect of the present invention, based on the premise of the first or second aspect, the angle between the plurality of linear partition members and the vector direction of the uniaxial orientation process is zero.
A liquid crystal panel frame characterized by being at an angle of up to 30 °.

The invention described in claim 4 is the invention according to claims 1 to 3
Assuming the invention described in the above, the pair of substrates has an alignment film subjected to uniaxial alignment processing, and the direction of the uniaxial alignment processing vector is both directed to the open end or the opposite direction. A liquid crystal panel frame.

According to a fifth aspect of the present invention, at least one of a pair of transparent substrates, a pair of electrodes formed on the substrates and facing each other, and a predetermined interval provided between the two substrates. A plurality of linear partition members arranged in parallel with each other, and an alignment film formed on at least one of the pair of substrates and subjected to a uniaxial alignment treatment, The plurality of linear partition members extend substantially in parallel to the direction of the uniaxial alignment treatment, and a portion other than the liquid crystal passing opening formed at one end of the plurality of linear partition members is further provided. A liquid crystal panel body characterized by forming a linear space sealed with respect to a liquid, and further enclosing a ferroelectric liquid crystal or an antiferroelectric liquid crystal inside each of the linear spaces. .

The invention according to claim 6 is based on the invention according to claim 5, wherein the ferroelectric liquid crystal or the antiferroelectric liquid crystal is cooled from a side opposite to an end of the opening through which the liquid crystal passes. A liquid crystal panel, which is oriented by gradient cooling.

The inventor of the present application has solved the problem of the occurrence of cracks and non-uniform density in the liquid crystal panel caused by the difference in the flowability of the liquid crystal in the direction of the liquid crystal layer and the normal direction of the layer due to the insufficient liquid crystal filling density. By adjusting the sealing method, the direction of the uniaxial alignment treatment, and the direction of the liquid crystal permeation, it was found that the liquid crystal could be filled at a high density and the entire liquid crystal panel could be made uniform and crackless.

As described above, in the smectic liquid crystal, the flowability in the in-layer direction and the layer normal direction is generally larger in the in-layer direction than in the layer normal direction. If the direction of the uniaxial alignment treatment is parallel to the direction in which the partition walls extend, it is considered that cracks may occur because the partition walls have a high flowability of the liquid crystal and are blocked short by the partition walls. Can be Further, since the liquid crystal has a certain degree of fluidity, display unevenness may occur due to non-uniform density of the liquid crystal. The key to these two problems is the density of the liquid crystal in the panel.

The present inventor has paid attention to this point, and has found a method for solving the problem by filling the liquid crystal with high density. The problem of crack generation is caused by the change in the density of the liquid crystal when the temperature drops, and the problem of non-uniformity of the liquid crystal is caused by the non-uniform density distribution. By filling the liquid crystal in the linear space to the limit, that is, filling the liquid crystal at a high density, it is possible to mitigate and accommodate the density change during the temperature drop inside the liquid crystal, and prevent the occurrence of cracks It becomes possible.
In addition, by packing the liquid crystal at a high density such that the fluctuation of the density of the liquid crystal in the panel is not seen, a liquid crystal panel body which is uniform as a whole can be obtained.

When the structure of the liquid crystal panel frame according to the first aspect is used as shown in FIG. 4 as an example, all the portions except for the liquid crystal passing opening formed at one end of the plurality of linear partition members are sealed. There is no escape for the liquid crystal.Therefore, when the liquid crystal is sealed, the inside of the panel is once depressurized and then closed at the liquid crystal opening end to return to the atmospheric pressure. Can be filled.
At this time, since the partition wall is present between the pair of substrates of the liquid crystal panel frame, the sealing speed is higher than the case where there is no partition wall due to the surface tension of the liquid crystal and the partition wall, and the flow and filling direction of the liquid crystal can be regulated. The liquid crystal can be more uniformly packed than in the case where there is no partition, and the fluctuation of the density due to the flow of the liquid crystal after the completion of the liquid crystal panel body can be limited.

In order to pack the liquid crystal at a higher density, it is effective to apply a temperature gradient cooling method to the liquid crystal panel body. As described above, the temperature gradient cooling method is a method in which the liquid crystal flows by using the volume contraction caused by the temperature drop of the liquid crystal itself as a driving force, so that the liquid crystal is cooled from the side opposite to the liquid crystal opening end of the liquid crystal panel body. It is possible to obtain a high-density packing and defect-free orientation. At this time, it is desirable that the pair of substrates is bonded. The gap may be unavoidably provided in the partition wall to such an extent that the effect of the temperature gradient cooling is not impaired.

When the temperature gradient cooling is performed, by setting the direction of the uniaxial alignment vector in accordance with the liquid crystal to be used and the uniaxial alignment process, the layer is bent in a desired direction, and zigzag defects and linear defects are eliminated. Without cracks
A panel body without uneven density can be obtained.

As described above, various types of uniaxial alignment treatment can be considered, but in general, a method of rubbing an organic alignment film is often used. When this rubbing method is applied to a pair of substrates, there are types such as antiparallel, parallel, and single-side rubbing depending on the combination of rubbing directions.

In the case of antiparallel rubbing (see FIG. 5B), no matter which direction the layer bends, the same stability is obtained due to the relationship between the pretilt of the smectic liquid crystal and the bending direction of the layer. Since the orientation does not differ depending on the direction of cooling, it is only necessary to cool from the side opposite to the open end in order to obtain a uniform orientation without cracks. However, in the case of parallel rubbing (see FIG. 5A) or one-sided rubbing, the stability differs depending on the bending direction of the layer, and generally C2 is more stable than C1. Either phase can be created by using the temperature gradient cooling method.However, in order to create a liquid crystal panel without cracks and uneven density, the direction of the temperature gradient cooling is opposite to the opening end. Need to be cooled. Therefore, when a panel body considering the direction of the uniaxial orientation treatment is prepared so as to produce a desired C1 or C2 phase when a temperature gradient cooling is applied in this direction, zigzag and linear defects are generated. And a panel body free from cracks and uneven density can be obtained (see FIG. 6).

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention, particularly the structural features, will be described below. An example of a typical liquid crystal panel frame (body) according to the present invention is shown in FIGS. 4A and 4B. This liquid crystal panel body has a structure in which at least one of the liquid crystal driving electrodes 402 is formed on a pair of transparent substrates 401,
For example, a plurality of linear partition members 404 having a layer 403 that has been subjected to a uniaxial orientation treatment such as applying an organic orientation film and performing rubbing, and arranged in parallel with each other at a predetermined interval between the substrates. And the angle [theta] between the direction of the uniaxial orientation treatment and the partition wall is set to be substantially parallel to 0 to 30 [deg.]. By sealing the peripheral portions of the pair of substrates formed as described above with the sealing material 406 except for the opening end portions, the openings for liquid crystal passage formed at one end of the plurality of linear partition members are formed. A liquid crystal panel frame is completed in which a linear space is formed in a state in which portions other than the ends are sealed with respect to the liquid. Then, a liquid crystal 405 having a layer structure is sandwiched in a linear space of the liquid crystal panel body. Preferably, the pair of substrates are bonded by the partition walls, and the liquid crystal is a ferroelectric liquid crystal or an antiferroelectric liquid crystal.

The partition is preferably formed as a linear one at intervals of 20 to 800 μm (pitch). By optimizing the partition pitch in this range, the liquid crystal permeation straightness is improved and the mobility at the time of temperature gradient cooling is increased. In a more desirable form, when the pair of substrates are bonded by the partition walls, the impact resistance is remarkably improved, and the effect of the temperature gradient cooling method is remarkable.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of a liquid crystal panel to be manufactured is the same as that shown in FIG. Polyimide (Hitachi Chemical Co., Ltd. HL1110) is applied to a pair of substrates with electrodes as an alignment film, and a positive resist (Shipley Far East Co., Ltd. MP) is applied to one of the substrates.
1400-25) to form stripe-shaped barrier ribs having a height of 1.5 μm (pitches of 100 μm and 300 μm). The rubbing direction was such that the vector direction of both of the pair of substrates was opposite to the opening end for liquid crystal transmission, and the angle θ ° with the partition wall was θ = 0. In this manner, the peripheral portions of the pair of substrates were sealed with epoxy resin except for the open ends provided at one ends of the plurality of linear partition members.

A ferroelectric liquid crystal (CS1014, Chisso Corporation) was sealed in the liquid crystal panel frame, and the orientation, the rate of occurrence of liquid crystal cracking, and the degree of unevenness in the initial state and in the direction of temperature gradient cooling were examined. The qualitative evaluation (three ranks of ○ △ ×) was performed for the orientation and unevenness, and the ratio of the occurrence of the liquid crystal cracks among a large number of linear spaces partitioned by partition walls was summarized (Table). 1). Regarding the direction of the temperature gradient, the direction of cooling from the side opposite to the opening end, that is, the direction of packing the liquid crystal, is called the forward direction, and the direction of cooling from the side of the opening end, that is, the direction of drawing the liquid crystal, is called the reverse direction. For comparison, a liquid crystal panel body in which liquid crystal was sealed by capillarity by providing an opening end on the opposite side of the opening end of the panel body was also prepared. From the comparison with this liquid crystal panel body, it was found that the structure of the liquid crystal panel frame described in claim 1 was effective in terms of both cracks and unevenness reduction. Further, it has been found that by applying the temperature gradient cooling to the liquid crystal panel body in the forward direction, not only cracks and unevenness but also the orientation of the liquid crystal is improved. The orientation at this time was the C2 orientation, and by setting the rubbing direction toward the opening end, it was possible to obtain the same high-quality C1 orientation.

[0032]

[Table 1]

[0033]

As described above, according to the present invention,
By sealing the peripheral portion of the liquid crystal panel frame with the partition except for the opening end portion for passing the liquid crystal, it is possible to reduce cracks and non-uniform density of the liquid crystal. In addition, when performing temperature gradient cooling, a liquid crystal panel body in which the directions of sealing and uniaxial alignment processing are appropriately set is created, and cooling is performed in a direction in which liquid crystal is packed, so that a desired alignment state such as C1, C2 is obtained. Make it,
The problem of defects, cracks and uneven density can be solved.

[0034]

[Brief description of the drawings]

FIG. 1 is a perspective sectional view of a panel body according to a conventional technique.

FIG. 2 is an explanatory view showing a layer structure change in a panel in a temperature gradient cooling method.

FIG. 3 is an explanatory diagram showing the direction of uniaxial orientation processing and the occurrence of cracks.

FIG. 4 is a perspective sectional view (A) and a bird's-eye view (B) of the panel body according to the present invention.

FIG. 5 is an explanatory diagram showing a difference in orientation depending on a rubbing direction and a bending direction of a layer.

FIG. 6 is an explanatory diagram showing a difference in orientation between a liquid crystal sealing direction, a rubbing direction, and a temperature gradient cooling direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Substrate 102 Liquid crystal drive electrode 103 Alignment film 104 Partition member 105 Liquid crystal 301 Layer normal direction 302 Liquid crystal crack (crack) 303 In-layer direction 401 Substrate 402 Liquid crystal drive electrode 403 Alignment film 404 Partition member 405 Liquid crystal 406 Sealant

Continuation of front page (72) Inventor Shoji Higuchi 1-5-1, Taito, Taito-ku, Tokyo Letterpress Printing Co., Ltd. F-term (reference) 2H089 LA02 LA09 LA18 LA19 LA20 MA04X MA04Y NA05 NA13 NA24 NA25 NA35 NA60 QA11 QA12 QA15 RA13 RA14 TA04 2H090 HB08Y HC05 HD14 JC17 JD14 KA14 KA15 LA02 MA05 MA07 MB02 MB13

Claims (6)

[Claims] 1. A pair of substrates, at least one of which is transparent, a pair of electrodes formed on the substrates and facing each other, and arranged in parallel with each other at a predetermined interval provided between the two substrates. A plurality of linear partition members, and an alignment film formed on at least one of the pair of substrates and subjected to a uniaxial alignment treatment. Extends substantially parallel to the direction of the uniaxial alignment treatment, and a portion other than the liquid crystal passing opening formed at one end of the plurality of linear partition members is sealed with respect to the liquid. A liquid crystal panel frame characterized by forming a linear space in a state. 2. The method according to claim 1, wherein the plurality of linear partition members are 20 to 80.
2. The liquid crystal panel frame according to claim 1, wherein the liquid crystal panel frames are arranged at an interval of 0 [mu] m. 3. The liquid crystal panel frame according to claim 1, wherein the angle between the plurality of linear partition members and the vector direction of the uniaxial orientation processing is 0 to 30 °. 4. A method according to claim 1, wherein said pair of substrates have an alignment film to be subjected to a uniaxial alignment process, and both directions of vectors of the uniaxial alignment process are directed to an open end or a direction opposite thereto. The liquid crystal panel frame according to any one of claims 1 to 3, wherein: 5. A pair of substrates at least one of which is transparent, a pair of electrodes formed on those substrates and facing each other, and arranged in parallel with each other at a predetermined interval provided between the two substrates. A plurality of linear partition members, and an alignment film formed on at least one of the pair of substrates and subjected to a uniaxial alignment treatment. Extends substantially parallel to the direction of the uniaxial alignment treatment, and a portion other than the liquid crystal passing opening formed at one end of the plurality of linear partition members is sealed with respect to the liquid. A liquid crystal panel body, wherein a linear space in a state is formed, and a ferroelectric liquid crystal or an antiferroelectric liquid crystal is sealed in each of the linear spaces. 6. The ferroelectric liquid crystal or the antiferroelectric liquid crystal,
6. The liquid crystal panel body according to claim 5, wherein the liquid crystal panel body is oriented by a temperature gradient cooling for cooling from a side opposite to an end of the liquid crystal passage opening.