JP2000193952A - Liquid crystal element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of air bubbles in a display section of a liquid crystal element and the occurrence of a display defect. SOLUTION: A substrate which curls to recess with respect to the side in contact with a liquid crystal composition 5 at the time of heating up and is >=0.5 mm per 1 cm in the length of the substrate in the curling amt. is used for at least one of a pair of the substrates 2 and 3 of the liquid crystal element 1 constituted by forming a closed space between a pair of substrates 2 and 3 disposed to face each other and packing a liquid crystal composition 5 into the closed space. Namely, if the substrate which curls to recess with respect to the side in contact with the liquid crystal composition 5 at the time of heating up is used for at least one (for example, the upper substrate 2) of a pair of the substrates, pressure is applied to the liquid crystal layer by the force of the substrate tending to resume flatness by packing the liquid crystal composition into the closed spacing in the heated up state and restoring the ordinary temperature after end-sealing. The pressure in the liquid crystal element does no longer turns to excessive negative pressure and the generation of the air bubbles is prevented.

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, and more particularly, to a liquid crystal device in which a display defect caused by generation of bubbles in a liquid crystal layer in a display area is prevented.

[0002]

2. Description of the Related Art Since liquid crystal elements are thin, lightweight, and excellent in power saving, they have been used in various fields. At present, the use of liquid crystal elements as display elements is particularly conspicuous. It is used as a display element of various portable electronic devices, such as a personal computer, a word processor, a small television, a monitor of a video camera and a digital camera, a mobile phone, an electronic organizer, etc., as a device that makes full use of its features. In addition to the use as a display element or a display device, there is a use as a light control unit or a large-aperture light modulation unit.

Here, an example of a liquid crystal element is shown in FIGS. FIG. 5 is a plan view of the liquid crystal element with a part of the upper substrate removed, and FIG. 6 is a sectional view of a main part of the liquid crystal element. 5 and 6
As shown in the figure, the liquid crystal element 41 has wiring patterns 47, 4 made of a transparent conductive film such as ITO (indium tin oxide).
The liquid crystal composition 45 is sealed in a closed space between a pair of upper and lower transparent substrates 42 and 43 on which the substrate 8 and the alignment films 49 and 50 are formed. And the liquid crystal element 41 having such a structure
The wiring patterns 47 and 48 and the alignment films 49 and 50 made of a transparent conductive film are formed on two transparent substrates 42 and 43 made of a glass substrate or a plate-shaped or film-shaped plastic substrate.
After that, the two transparent substrates 42 and 43 are opposed to each other with a predetermined gap (cell gap) therebetween via a spacer 46, and the peripheral portion between the substrates is bonded with a sealant 44 to form a gap between the substrates. A liquid crystal composition 45 is formed by forming a closed space, injecting and filling a liquid crystal composition 45 into the closed space from a sealing hole 51 provided in a part of a seal portion, and sealing the sealing hole 51 with a sealant 52. It is.

A liquid crystal device having a structure as shown in FIGS. 5 and 6 generally has a structure in which a liquid crystal composition is sandwiched between two glass substrates. In this case, since the device is much thinner and lighter and the impact resistance is improved as compared with the case where a glass substrate is used, the device is suitable for portable use. However, when a liquid crystal device is manufactured using a polymer film as a substrate, a gas component may enter from the outside of the device and dissolve into the liquid crystal layer unless a device having characteristics such as gas barrier properties is used as the substrate.
When this gas component reaches a saturated state, if any external stimulus such as impact, pressure, rapid temperature change, etc. is applied to the liquid crystal element, this external stimulus will trigger bubbles in the liquid crystal element. Sometimes. Although this is infrequent, it may be observed even in a liquid crystal element using a glass substrate. Then, since a portion of the liquid crystal element where bubbles are generated is not filled with liquid crystal, an image defect such as lack of display occurs in that portion,
The display quality is significantly impaired, and the liquid crystal element does not function.

In view of the above, various proposals have been made as follows as means for making it difficult for bubbles to be generated in a display area of a liquid crystal element. (1) Japanese Patent Application Laid-Open No. 5-142548 describes that by using a deformable hollow spacer, a decrease in internal pressure due to volume shrinkage of a liquid crystal material at a low temperature is mitigated and bubbles are prevented from being generated. ing. (2) Japanese Patent Application Laid-Open No. 8-313889 discloses a panel structure in which a portion where bubbles easily collect (bubble capturing portion) is provided in a non-screen region so that even if bubbles are generated, they are not made to be visible. (3) Japanese Patent Application Laid-Open No. Hei 9-101528 describes that in a liquid crystal display device having a plastic substrate, the surfaces of a plastic substrate and a sealing material are covered with a gas barrier material to prevent bubbles from being generated. (4) Japanese Patent Application Laid-Open No. 9-22003 discloses that a liquid crystal display device using a plastic film has excellent heat resistance, flexibility, transparency, moisture resistance, solvent resistance, and extremely high humidity dependence of gas barrier properties. It is described that a small gas barrier layer is provided on a plastic substrate to prevent generation of bubbles. (5) JP-A-8-304832 describes that bubbles are prevented from being generated at a low temperature by using the difference in elasticity between a glass fiber spacer having a small diameter and a plastic bead spacer having a large diameter. (6) JP-A-7-230090 discloses a color LC.
D, a film LCD, a plastic LCD and the like using a substrate having an organic film, an alignment film pattern provided on the substrate is formed so as to be in contact with the sealing resin,
It is described that adsorption gas and moisture generated from the substrate are suppressed to prevent generation of bubbles. (7) JP-A-6-11699 discloses that, in order to prevent point defects due to bubbling of dissolved gas in a liquid crystal cell even at a low temperature or a mechanical shock, a polystyrene-based liquid crystal cell is used in addition to a normal spacer. It describes that a gas adsorbent composed of porous particles is sprayed.

[0006]

As described above, various proposals have been made as a countermeasure against bubbles in a liquid crystal element.
In the prior art of (1), the use of a deformable hollow spacer can alleviate the internal pressure decrease due to the volume shrinkage of the liquid crystal material at low temperatures and prevent bubbles from being generated. When an impact is applied, the impact cannot be completely absorbed, and the generation of bubbles cannot be reliably prevented. In addition, it is difficult to form a hollow spacer having a minute and uniform diameter, and the material cost increases and the manufacturing cost increases. In the prior art (2) above, bubbles generated in the effective screen area are moved to the bubble capturing section in the non-screen area and fixed, but this method cannot prevent bubbles from being generated in the effective screen area. However, the occurrence of temporary display defects is inevitable. In the prior arts (3) and (4), a gas barrier layer is provided on a plastic substrate to prevent gas and moisture from penetrating through the substrate and entering the inside to prevent the generation of bubbles. No measures have been taken against gas originally dissolved in the liquid crystal, or when gas barrier has been deteriorated or damaged, and any external stimulus such as shock, pressure, rapid temperature change, etc. has been applied to the liquid crystal element. Will generate bubbles. In the prior art (5), two types of spacers having different diameters are interposed between the two substrates.
In this case, when an external impact is applied to the substrate surface of the liquid crystal element, the impact cannot be completely absorbed and the generation of bubbles cannot be reliably prevented. In addition, it is difficult to uniformly disperse and arrange two types of spacers having different diameters, and the cell gap may become nonuniform, which causes display unevenness. In addition, since two types of spacers are used, the material cost increases and the manufacturing cost increases. In the prior art of the above (6), the alignment film pattern provided on the substrate is formed so as to be in contact with the sealing resin and has the same function as the gas barrier, but is the same as the prior art of the (3) and (4). The problem remains, and bubbles are generated when an external stimulus is applied. In the prior art of the above (7), a gas adsorbent composed of polystyrene-based porous particles is dispersed in the liquid crystal cell in addition to the ordinary spacer, so that the gas in the liquid crystal is adsorbed to prevent bubbles from being generated. However, the adsorbing capacity of the gas adsorbent is limited, and if there is a passage of gas over time from the substrate or the seal part, the generation of air bubbles cannot be suppressed and the fundamental cause of air bubble generation It is not a rejection. In addition, since two types of materials, ie, a spacer and a gas adsorbent, are used, the material cost increases and the manufacturing cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of claims 1 and 2 is to provide a liquid crystal element which has a novel and simple structure and can avoid the defect of bubble generation. It is. The purpose of claims 3, 4, and 5 is
An object of the present invention is to provide a liquid crystal element which can avoid the defect of bubble generation from its root cause with a new and simple configuration. A sixth object of the present invention is to provide a liquid crystal element capable of permanently avoiding the defect of bubble generation. A seventh object of the present invention is to provide a liquid crystal element which is excellent in portability and impact resistance while avoiding a defect such as generation of bubbles.

[0008]

According to a first aspect of the present invention, a closed space is formed between a pair of opposed substrates, and a liquid crystal composition is filled in the closed space. In the liquid crystal element formed by the above method, at least one of the pair of substrates curls concavely with respect to the side in contact with the liquid crystal composition when the temperature is raised, and the curl amount is 0.5 mm or more per 1 cm of the length of the substrate. This is a configuration using a certain substrate. That is, in the liquid crystal device according to claim 1, since at least one of the pair of substrates uses a substrate that curls concavely with respect to the side that comes into contact with the liquid crystal composition when the temperature is raised, the liquid crystal composition is filled at the elevated temperature. After sealing and returning to room temperature, the curling substrate tends to return to a flat state, which acts on the liquid crystal layer to constantly apply pressure to the liquid crystal layer.
The pressure in the liquid crystal element does not become excessively negative, and the generation of bubbles is prevented.

According to a second aspect of the present invention, in a liquid crystal element formed by forming a closed space between a pair of opposed substrates and filling the closed space with a liquid crystal composition, the periphery of the pair of substrates is provided. The sealing member surrounding the liquid crystal composition is not completely closed, and a part of the liquid crystal composition is in contact with the outside air. That is, in the liquid crystal element of claim 2, since a part of the sealing material is not completely closed and a part of the liquid crystal composition is in contact with the outside air, the pressure in the liquid crystal element becomes an excessive negative pressure. And the generation of air bubbles is prevented.

According to a third aspect of the present invention, in a liquid crystal element formed by forming a closed space between a pair of opposed substrates and filling the closed space with a liquid crystal composition, a non-pixel outside a display area is formed. In this configuration, a gas absorbing portion for absorbing gas contained in the liquid crystal composition is provided in the portion. That is, in the liquid crystal device according to the third aspect, gas molecules dissolved in the liquid crystal composition and potentially causing the generation of bubbles move to the non-pixel portion before the bubbles become apparent and are absorbed by the gas absorbing portion. In addition, generation of bubbles is prevented.

According to a fourth aspect of the present invention, there is provided a liquid crystal device comprising a liquid crystal composition and a spacer for keeping a gap between the pair of substrates constant in a closed space between the pair of substrates facing each other. In a non-pixel portion outside the display region, a gas absorbing portion for absorbing gas contained in the liquid crystal composition is provided, and a gas separation film is provided between the liquid crystal composition and the gas absorbing portion provided in the non-pixel portion. It is configured to be provided. That is, in the liquid crystal device according to claim 4, the gas molecules dissolved in the liquid crystal composition and potentially causing the generation of bubbles are moved to the non-pixel portion before the bubbles appear, and the liquid crystal composition is separated by the gas separation film. Since the gas is separated from the gas and absorbed by the gas absorbing section, generation of bubbles is prevented.

According to a fifth aspect of the present invention, there is provided a liquid crystal device comprising a liquid crystal composition and a spacer for keeping a constant gap between the pair of substrates in a closed space between the pair of substrates facing each other. The non-pixel portion outside the display region is provided with a gas absorbing portion for absorbing gas contained in the liquid crystal composition, and the gas absorbing portion is provided with a gas absorber having a higher gas solubility than the liquid crystal composition. Things. That is, in the liquid crystal device according to the fifth aspect, the gas molecules dissolved in the liquid crystal composition and potentially causing the generation of bubbles move to the non-pixel portion before the bubbles become apparent and are absorbed by the gas absorber. Since they are permanently retained, the generation of bubbles is prevented.

[0013] The invention according to claim 6 is the invention according to claim 3 or 4.
Or the liquid crystal device according to 5, wherein gas can move from the liquid crystal composition to the gas absorbing portion provided in the non-pixel portion, but gas cannot move from the gas absorbing portion to the liquid crystal composition. It is what it was. That is, in the liquid crystal device according to the sixth aspect, since the gas dissolved in the liquid crystal composition is moved to the non-pixel portion not related to display and is irreversibly absorbed and stays in the gas absorbing portion, the generation of bubbles is prevented. .

According to a seventh aspect of the present invention, in the liquid crystal device according to any one of the first to sixth aspects, at least one of the pair of substrates is made of a polymer film. That is, in the liquid crystal device according to the seventh aspect, by using a polymer film substrate in addition to the configuration according to any one of the first to sixth aspects, the liquid crystal device is excellent in lightweight portability, impact resistance, safety, and does not generate bubbles. Is realized.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure, operation and operation of the present invention will be described below in detail with reference to the drawings. 5 and 6
As shown in FIG. 1, in a general liquid crystal element 41, a pair of upper and lower substrates 42 and 43 are bonded to each other at a peripheral portion by a sealant 44, and the interval is uniformly maintained by a spacer 46. Then, the liquid crystal composition 45 is injected from a sealing port 51 provided in a part of the sealant 44, introduced into a gap (closed space) formed by the upper and lower substrates 42, 43 and the sealant 44, and filled therein. . Conventionally, after filling the liquid crystal composition 45, in order to prevent outside air from flowing in from the sealing port 51 or to prevent the liquid crystal composition 45 from flowing out,
The sealing port 51 was sealed with a kind of adhesive called a sealant 52.

In the liquid crystal device having the above-mentioned conventional structure, when the environmental temperature is lowered, a minute bubble-like liquid crystal deficient portion (which is also interpreted as a bubble in a broad sense) is generated due to volume contraction of the liquid crystal composition,
Defects display quality. Further, in a liquid crystal element using a flexible substrate such as a plastic substrate, a gas easily permeates from the outside, or a gas emitted from the substrate or a device built-in element easily appears as bubbles. In the case of a flexible substrate, the gas dissolved in the liquid crystal in the liquid crystal element is likely to become bubbles as a result of stimulation of external temperature, atmospheric pressure or mechanical force. Therefore, the present inventors have found the following as causes of bubbles generated in the liquid crystal element through various experiments and considerations. When the gas cannot be present in the liquid crystal element to the extent that the gas is manifested as bubbles, that is, a liquid having a low gas permeability from the outside (a gas barrier having a large gas barrier property) such as a liquid crystal element formed of a glass substrate In the case of ()), bubbles are generated due to rapid volume contraction of the liquid crystal composition due to a decrease in temperature. In other words, by making the inside of the element negative pressure,
The dissolved gas is vaporized and bubbles are generated. In a liquid crystal element using a plastic substrate having relatively high gas permeability, the amount of gas present in the liquid crystal element (dissolved amount) increases with time, and the gas dissolved in the liquid crystal composition exceeds a certain limit (saturated solubility). In the supersaturated state, there is a fact that "bubble nuclei", which become nuclei of bubbles, are generated and grown by external mechanical stimulation.

The present invention is based on the above-mentioned causes of the generation of bubbles and takes measures to prevent them. First, in the liquid crystal device having a sealed structure as shown in FIGS. 5 and 6, when the sealant is partially cut or a minute hole is formed in the substrate, the liquid crystal device is introduced into the device. It has been found that, in a liquid crystal element in which the amount of outside air is small, bubbles are hardly generated even if any external stimulus is applied, and even if they are generated, they disappear within a short time. This is the same even when the pressure inside the liquid crystal element is higher than that outside and the liquid crystal composition naturally flows out when the element is opened.

The present inventors have arrived at the present invention from such observations. As one means for preventing the generation of air bubbles, at least one of a pair of substrates is provided with a liquid crystal composition at the time of heating. A configuration in which a substrate curls concavely with respect to the contacting side is used to prevent the inside of the device from becoming negative pressure. Further, as another means for preventing the generation of bubbles, a part of a conventionally sealed sealant is opened so that a part of the liquid crystal composition is in contact with the outside air, and the inside of the element is formed. Is prevented from becoming negative pressure (claim 2).

Further, in the present invention, as another means for preventing the generation of air bubbles, it is necessary to prevent the generation of air bubbles without being influenced by the gas dissolved amount of the liquid crystal composition inside the liquid crystal element, which is the root cause. The non-pixel portion outside the display region is provided with a gas absorbing portion that absorbs a gas contained in the liquid crystal composition, and the gas contained in the liquid crystal composition is irreversibly moved to the non-pixel portion outside the display region to produce a gas. By absorbing the gas in the absorbing section, the dissolved gas in the liquid crystal composition is reduced, and the generation of bubbles is permanently suppressed (claims 3 to 6). Hereinafter, specific examples of the present invention will be described.

(Embodiment 1: Embodiment of Claim 1) FIG. 1 is an explanatory view showing the structure of a liquid crystal device according to an embodiment of the present invention.
(A) is a schematic sectional view showing a state of the liquid crystal element at the time of temperature rise,
(B) is a schematic sectional view showing a state of the liquid crystal element at normal temperature,
FIG. 3C is a partial cross-sectional view illustrating a configuration of a substrate that curls when the temperature is raised, and FIG. 4D is a plan view illustrating a liquid crystal element excluding a part of an upper substrate. In the liquid crystal element 1 shown in FIG. 1, a pair of upper and lower substrates 2 and 3 are bonded to each other at a peripheral portion by a sealant 4, and the interval is uniformly held by a spacer (not shown). Then, the liquid crystal composition 5 is injected from a sealing port 6 provided in a part of the sealant 4, introduced into a gap (closed space) formed by the upper and lower substrates 2 and 3 and the sealant 4 and filled therein. . After the filling of the liquid crystal composition 5, the sealing port 6 is sealed with a sealing agent 52.

The liquid crystal device shown in FIG.
6 has the same structure as the liquid crystal element shown in FIG. 6, but in this embodiment, at least one of the pair of substrates 2 and 3 (FIG.
In the example of (1), the upper substrate 2) curls concavely with respect to the side in contact with the liquid crystal composition 5 at the time of raising the temperature (the state shown in FIG. 1 (a)). A certain substrate 2 is used. When the liquid crystal composition 5 is injected, the temperature of the substrate 2 is raised to a temperature at which the substrate 2 is likely to curl. After the liquid crystal composition 5 is filled and sealed, the substrate temperature is lowered to room temperature. At this time, as shown in FIG. 1B, the pressure inside the liquid crystal element 1 is increased by the force for returning the substrate 2 to the flat state, so that the pressure is constantly applied to the liquid crystal layer. Even if the temperature is lowered, the pressure in the liquid crystal element does not become excessively negative. Therefore, in the liquid crystal element 1 having such a structure, bubbles are not generated even at a low temperature, and bubbles are hardly generated even when any external stimulus is applied. Disappear in time.

In the example shown in FIG. 1, the upper substrate 2 is curled, but the upper and lower substrates 2 and 3 may be curled. The curl amount of the substrate is preferably 1.0 mm or more per 1 cm of the length of the substrate,
It is 4.0 mm or less. This is because if the amount of curl of the substrate is small, the liquid crystal cannot be sufficiently pressurized when the temperature returns to normal temperature, and if too large, the sealant 4 is broken at the time of heating, and the liquid crystal element cannot be formed.

The substrate having the property of curling by heating as described above can be obtained by forming layers having different elasticities depending on temperature. For example, as shown in FIG. 1C, a layer (for example, polyethylene or the like) 2b made of a material having a higher thermal expansion than the polycarbonate is applied to one surface of a film substrate 2a made of a polycarbonate having a relatively low thermal expansion. And the like.

As a general method for filling the liquid crystal composition 5 into an empty liquid crystal element, the empty element is evacuated while the sealing port 6 shown in FIG. The liquid crystal composition 15 is filled in the device by immersing the sealing port 6 of the device in the liquid crystal composition 5 in a heated state and returning the pressure to the atmospheric pressure. At this time, if the immersion is continued for a sufficient time, the pressure inside the element is not so low, and becomes almost atmospheric pressure. Then, after the filling of the liquid crystal composition 5 is completed, the sealing port 6 is sealed with the sealing agent 7 and the temperature is returned to normal temperature, whereby the liquid crystal element 1 of this embodiment is obtained.

Now, a liquid crystal device 1 having the structure shown in FIG. 1 was actually manufactured, and tests such as pressing the tip of a ballpoint pen against the substrate surface were performed. There was no failure to generate air bubbles.

(Embodiment 2: Embodiment of Claim 2) FIG. 2 is a view showing another embodiment of the present invention, and is a schematic plan view of a liquid crystal element excluding a part of an upper substrate. In the liquid crystal element 11 shown in FIG.
The peripheral portions are bonded together by a spacer 4, and the spacing is uniformly maintained by a spacer (not shown). Then, the liquid crystal composition 15 is injected from a sealing port 16 provided in a part of the sealant 14, introduced into and filled in a gap (closed space) formed by the upper and lower substrates 12 and 13 and the sealant 14. .

The liquid crystal element 11 shown in FIG. 2 has basically the same structure as that of the liquid crystal element shown in FIGS. A partition 17 for a sealant extending into the closed space is provided to form a narrow passage 18 in a non-image portion in the liquid crystal layer, and a sealing port 16 conventionally sealed is opened. .

According to the study of the present inventors, the pressure of the surrounding air,
Since the substrates 12, 13 and the liquid crystal composition 15 expand and contract due to changes in temperature and humidity, etc., when the passage 18 as shown in FIG. 2 is not provided, that is, in the configuration of FIG. In this case, the liquid crystal composition leaks from the sealing opening to the outside, or conversely, outside air enters the liquid crystal layer from the sealing opening to generate air bubbles, which tends to cause problems such as poor display. However, as shown in FIG. 2, in the case of a configuration in which a thin passage 18 communicating with the sealing port 16 is provided in the liquid crystal layer of the liquid crystal element 11, the passage 18 has a pressure adjusting function,
Even if the substrates 12, 13 and the liquid crystal composition 15 expand and contract due to changes in ambient pressure, temperature and humidity, etc., the pressure in the liquid crystal element 11 is substantially reduced due to the movement of the liquid level in the passage 18. It is kept constant, so that the liquid crystal composition 15 does not leak to the outside and the inside of the device does not have an excessive negative pressure. Further, even when an external impact is applied to the substrate surface, the impact is absorbed by the movement of the liquid surface in the passage 18. Therefore, in the liquid crystal element 11 having the configuration shown in FIG. 2, generation of bubbles in the image display area can be prevented.

In order to provide the function of pressure adjustment to the passage 18 of the liquid crystal element 11 shown in FIG. 2, the passage 18 needs to be sufficiently long. The liquid level of the liquid crystal composition 15 at normal temperature and normal pressure
It is preferable that the length of the portion 8 is about halfway.

Further, when manufacturing the liquid crystal element 11 having a structure having the passage 18 as shown in FIG.
As a method of filling the empty liquid crystal element 5 with an empty liquid crystal element, the empty element is evacuated while the sealing port 16 shown in FIG. By returning the pressure to the atmospheric pressure, the liquid crystal composition 15 is filled in the device. At this time, if the immersion is continued for a sufficient time, the pressure inside the element is not so low, and becomes almost atmospheric pressure. Then, by adjusting the liquid level of the liquid crystal composition 5 in the passage 18, the liquid crystal element 1 of the present embodiment can be obtained.

The liquid crystal element 11 having the structure shown in FIG. 2 was actually manufactured, and tests such as pressing the tip of a ballpoint pen against the substrate surface were performed. There was no failure to generate air bubbles.

(Embodiment 3: Embodiments of Claims 3 to 7) FIG.
FIG. 9 is a view showing still another embodiment of the present invention, and is a schematic plan view of a liquid crystal element in which an upper substrate is not shown. The basic structure of the liquid crystal element section 21 of this liquid crystal element is substantially the same as that shown in FIGS. 5 and 6, but in this liquid crystal element,
A gas absorbing portion 30 for absorbing gas contained in the liquid crystal composition 25 is provided in a non-pixel portion other than the pixel portion (a hatched region surrounded by a dashed line in the drawing) 28 which is a display region. . FIG. 4 schematically shows a cross-sectional structure of a portion to which the gas absorbing section is connected. The liquid crystal element shown in FIGS. 3 and 4 is, for example, a liquid crystal element (liquid crystal cell) using a polymer (plastic) substrate as the upper and lower substrates 22 and 23. As the polymer substrate, PC (polycarbonate) or PET (polyethylene terephthalate) is used. ) Is used, a transparent electrode is patterned on the substrate surface, and the cell shape can be arbitrarily designed in advance. There are two manufacturing methods described below, but the method is not limited thereto.

(1): The liquid crystal element shown in FIGS. 3 and 4 is, for example, a liquid crystal having a cell shape as shown in FIG. 3 and comprising a pixel portion 28 and upper and lower substrates 22 and 23 constituting a peripheral portion thereof. It is divided into two blocks: an element part 21 and a gas absorbing part 30 composed of a gas-permeable or gas-impermeable substrate. The gas absorbing portion 30 is a closed system (bag shape) except for the portion of the gas separation membrane 29, and is suitable for the properties of the gas absorbing material such as injection or vacuum injection after the gas absorbing material 31 is previously cleaned by evacuation or the like. Fill with the filling method. The cells of the liquid crystal element section 21 are composed of an upper substrate 22 and a lower substrate 23.
Are opposed to each other via a spacer 32, and the peripheral portion thereof is bonded with a sealant 24 to form a closed space inside. The gas absorbing portion 3 is provided at one end of the liquid crystal element portion 21.
0 is connected by the sealant 24. Thereafter, liquid crystal is injected and filled into the closed space from the sealing port 26 of the liquid crystal element unit 21 by a vacuum injection method or the like, and the sealing port 27 is sealed with a sealant 27, whereby the configuration shown in FIGS. A liquid crystal element is obtained.

(2) Unlike the manufacturing method of the above (1), an upper substrate 22 and a lower substrate 23 in which the liquid crystal element portion 21 and the gas absorbing portion 30 are integrated are formed, and the upper and lower substrates 22, 2
3 are opposed to each other with a spacer 32 therebetween, and the periphery thereof is bonded with a sealant 24 to form a closed space inside, and the gas shown in FIG. A separation film 29 is provided, and sealing is performed so that the gas separation film 29 serves as a partition between the liquid crystal element unit 21 and the gas absorption unit 30.
The gas absorber 30 is filled with a gas absorber by a filling method suitable for the properties of the gas absorber, such as injection or vacuum injection, and the filling port is sealed. Next, liquid crystal is injected and filled into the closed space from the sealing port 26 of the liquid crystal element section 21 by a vacuum injection method or the like, and the sealing port 27 is sealed with a sealant 27, whereby the liquid crystal element having the configuration shown in FIG. Is obtained. In this case, the cross-sectional structure of the gas absorbing portion 30 is different from that in FIG. 4, and the upper and lower substrates 22 and 23 are integrated with the substrate of the gas absorbing portion 30.

In FIG. 3 and FIG. 4, it is appropriate to use a thin tape-like film corresponding to the cell gap as the gas separation film 29, but the gas separation function, that is, the liquid crystal composition 25 is permeated. Anything that can permeate only gas (gas) can be used. For example,
A hollow fiber membrane, a membrane membrane (for example, Gore-Tex membrane), a porous sealant, a porous metal sheet, a porous ceramic sheet (for example, porous aluminum borate), a stretched porous film, an alumite sheet, and the like are employed. However, avoid those that themselves emit gas.
As an example, the present inventors used a filter tape called Microtex using a porous film of tetrafluoroethylene resin (PTFE) manufactured by Nitto Denko.

The gas separation film 29 transmits gas which is dissolved or is going to be dissolved in the liquid crystal composition 25 in the liquid crystal element portion 21 and moves it to the gas absorbing portion 30, but does not transmit the liquid crystal composition 25. Fulfill. Gas absorption unit 30
The gas that has moved to is absorbed or adsorbed by the gas absorber 31 filled in the gas absorbing unit 30 and takes in the gas into the gas absorbing unit 30. When the substrate constituting the gas absorbing section 30 is gas impermeable, gas is stored here as a gas reservoir. In the case where the substrate constituting the gas absorbing section 30 is gas permeable, the gas is stored therein and then held in a state of equilibrium with the outside air.

As shown in FIG. 4, a gas absorber 31 is housed inside a gas absorber 30 in a non-pixel portion.
It is desirable that the gas absorber 31 shown in FIG. 4 be filled in the gas absorbing section 30 without any gap, but the properties may be liquid or solid. Further, the gas absorber 31 preferably has a large gas absorption capacity, such as a porous solid such as silica gel or molecular sieves, or a liquid having a large gas absorption capacity such as NMP.

In FIGS. 3 and 4, gas permeates into the liquid crystal element 21 from the outside via the upper and lower substrates 22 and 23, and after a long time, the dissolution of the gas into the liquid crystal composition 25 becomes saturated. And reaches supersaturation. In order to avoid this, in the liquid crystal element of FIG. 4, gas can be moved to and stored in the gas absorbing portion 30 of the non-pixel portion through the gas separating film 29. The gas stored in the gas absorbing section 30 is adsorbed or dissolved by the gas absorber 31 having a much larger gas absorbing capacity than the liquid crystal composition 25, so that the gas transfer is performed irreversibly.

When the substrate constituting the gas absorbing section 30 is gas-impermeable and the gas absorbing body 31 is liquid, the gas is stored as a gas reservoir. When the substrate constituting the gas absorbing unit 30 is gas-permeable,
The gas absorber 31 is desirably a solid. In this case, the gas that has passed through the gas separation membrane 29 and moved to and stored in the gas absorbing unit 30 is adsorbed by the gas absorbing body 31, and when the pressure inside the gas absorbing unit 30 becomes higher than the outside pressure, the gas is discharged to the outside. discharge. As a result, the internal pressure of the entire liquid crystal element can be constantly maintained near the external pressure.

Therefore, in the liquid crystal device having the structure shown in FIGS. 3 and 4, the gas permeated into the liquid crystal device 21 through the upper and lower substrates 22 and 23 is not affected by the gas absorbing portion 30 as described above. Since the liquid crystal is reversibly radiated to the outside again, the inside of the liquid crystal element 21 is controlled to an internal pressure at which bubbles are hardly generated, and the dissolved amount of gas in the liquid crystal composition is controlled to a gas dissolved amount at which bubbles are not generated. Can be.

[0041]

As described above, in the liquid crystal device according to the first aspect, at least one of the pair of substrates curls concavely with respect to the side in contact with the liquid crystal composition when the temperature rises. 0.5mm per 1cm of substrate length
Since the above-described configuration using the substrate is used, the liquid crystal composition is filled and sealed at an elevated temperature, and if the temperature is returned to room temperature, the force of the curled substrate to return to flatness acts on the liquid crystal layer. As a result, pressure is constantly applied to the liquid crystal layer, so that the pressure in the liquid crystal element does not become excessively negative, and the generation of bubbles can be prevented. Therefore, it is possible to realize a liquid crystal element which has a relatively simple and low-cost configuration and eliminates the problem of display failure due to the generation of bubbles.

In the liquid crystal device according to the present invention, a part of the sealing material surrounding the liquid crystal composition is not completely closed by bonding the peripheral portions of the pair of substrates and a part of the liquid crystal composition is exposed to the outside air. Since it is configured to be in contact, the pressure in the liquid crystal element does not become excessively negative and the generation of bubbles can be prevented. Therefore, it is possible to realize a liquid crystal element which has a relatively simple and low-cost configuration and eliminates the problem of display failure due to the generation of bubbles.

In the liquid crystal device according to the third aspect, a gas absorbing portion for absorbing a gas contained in the liquid crystal composition is provided in the non-pixel portion outside the display region. The gas molecules that potentially cause the generation of bubbles move to the non-pixel portion before the bubbles become apparent and are absorbed by the gas absorbing portion, so that the generation of bubbles can be prevented.
Therefore, it is possible to realize a liquid crystal element that can solve the problem of display failure due to bubbles in the pixel portion from the root cause.

In the liquid crystal device according to the fourth aspect, a gas absorbing portion for absorbing gas contained in the liquid crystal composition is provided in the non-pixel portion outside the display region, and the gas absorbing portion is provided in the liquid crystal composition and the non-pixel portion. The gas molecules that are dissolved in the liquid crystal composition and potentially cause bubbles are generated in the non-pixel section before bubbles become apparent, because the gas Since it is moved and separated from the liquid crystal composition by the gas separation membrane and absorbed by the gas absorbing portion, the generation of bubbles can be fundamentally prevented. Therefore, it is possible to realize a liquid crystal element that can solve the problem of display failure due to bubbles in the pixel portion from the root cause.

In the liquid crystal device according to the fifth aspect, a gas absorbing portion for absorbing a gas contained in the liquid crystal composition is provided in the non-pixel portion outside the display region, and the gas absorbing portion is provided with a gas more than the liquid crystal composition. Since the gas absorber with high solubility is provided, gas molecules that are dissolved in the liquid crystal composition and potentially cause the generation of bubbles are moved to the non-pixel portion before the bubbles become apparent, and the gas molecules are absorbed. Since it is absorbed by the body and is permanently retained, the generation of air bubbles can be fundamentally prevented. Therefore, it is possible to realize a liquid crystal element that can solve the problem of display failure due to bubbles in the pixel portion from the root cause.

In the liquid crystal device of the sixth aspect, in addition to the constitution of the third, fourth or fifth aspect, gas can be transferred from the liquid crystal composition to the gas absorbing portion provided in the non-pixel portion. Since gas transfer from the gas absorbing portion to the liquid crystal composition is not possible, gas molecules dissolved in the liquid crystal composition are moved to a non-pixel portion not related to display and are irreversibly transferred to the gas absorbing portion. Since it is absorbed and retained in the air, the generation of air bubbles can be fundamentally prevented. In addition, by configuring the gas absorbing portion with a gas permeable substrate, the pressure inside the liquid crystal element and the amount of dissolved gas in the liquid crystal composition can be controlled to an optimal state, and the conditions under which bubbles are generated can be controlled. Can be permanently eliminated. Therefore, it is possible to realize a liquid crystal element that can permanently solve the problem of display failure due to bubbles in the pixel portion.

In the liquid crystal device according to the seventh aspect, in addition to the configuration according to any one of the first to sixth aspects, a polymer film is used for at least one of the pair of substrates. It is possible to realize a liquid crystal element which is excellent in performance and safety and in which the problem of display failure due to bubbles is eliminated.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory diagrams of a configuration of a liquid crystal element according to an embodiment of the present invention, in which FIG. 1A is a schematic cross-sectional view of the liquid crystal element when the temperature is raised, and FIG. FIG. 3C is a schematic cross-sectional view of the element, FIG. 3C is a partial cross-sectional view illustrating a configuration of a substrate that curls when the temperature is raised, and FIG.

FIG. 2 is a view showing another embodiment of the present invention, and is a schematic plan view of a liquid crystal element excluding a part of an upper substrate.

FIG. 3 is a view showing still another embodiment of the present invention,
FIG. 3 is a schematic plan view of a liquid crystal element, in which an illustration of an upper substrate is omitted.

4 is a cross-sectional view schematically showing a cross-sectional structure of a portion of the liquid crystal element shown in FIG. 3 to which a gas absorbing section is connected.

FIG. 5 is a view showing an example of a conventional liquid crystal element, and is a schematic plan view of the liquid crystal element excluding a part of an upper substrate.

FIG. 6 is a partial sectional view showing an example of a sectional structure of a conventional liquid crystal element.

[Explanation of symbols]

 1, 11, 21: liquid crystal element 2, 12, 22: upper substrate 3, 13, 23: lower substrate 4, 14, 24: sealant 5, 15, 25: liquid crystal composition 6, 16, 26: sealing port 7 , 27: Sealant 17: Partition 18: Passage 28: Pixel part (display area) 29: Gas separation film 30: Gas absorption part 31: Gas absorber 32: Spacer

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akihiko Kanemoto 1-3-6 Nakamagome, Ota-ku, Tokyo, Ricoh Co., Ltd. (72) Inventor Tomoaki Sugawara 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (72) Inventor Tatsuya Sato 1-3-6 Nakamagome, Ota-ku, Tokyo F-term in Ricoh Co., Ltd. 2H089 LA29 LA30 LA41 NA24 NA31 NA32 NA34 NA48 QA16 TA01 2H090 JB02 JB03 JC04 JC08 LA02 LA03

Claims (7)

[Claims] 1. A liquid crystal element formed by forming a closed space between a pair of opposed substrates and filling the closed space with a liquid crystal composition, wherein at least one of the pair of substrates has A liquid crystal element comprising a substrate which curls concavely with respect to a side in contact with a liquid crystal composition at a temperature and has a curl amount of 0.5 mm or more per 1 cm of the length of the substrate. 2. A liquid crystal device formed by forming a closed space between a pair of opposed substrates and filling the closed space with a liquid crystal composition. A liquid crystal element, wherein a part of a sealing material surrounding an object is not completely closed, and a part of a liquid crystal composition is in contact with outside air. 3. A liquid crystal element formed by forming a closed space between a pair of opposed substrates and filling the closed space with a liquid crystal composition, wherein a liquid crystal composition is formed in a non-pixel portion outside a display area. 1. A liquid crystal device, comprising: a gas absorbing portion for absorbing a gas existing in the liquid crystal device. 4. A closed space between a pair of opposed substrates,
In a liquid crystal element having a spacer for holding a gap between the liquid crystal composition and the pair of substrates constant, a non-pixel portion outside a display region is provided with a gas absorbing portion for absorbing gas contained in the liquid crystal composition. And a liquid crystal element comprising a gas separation film between the liquid crystal composition and a gas absorbing portion provided in a non-pixel portion. 5. A closed space between a pair of opposed substrates,
In a liquid crystal device in which a spacer for holding a gap between the liquid crystal composition and the pair of substrates constant is provided, a non-pixel portion outside a display area is provided with a gas absorbing portion for absorbing gas contained in the liquid crystal composition. And a gas absorber having a gas solubility higher than that of the liquid crystal composition in the gas absorbing portion. 6. The liquid crystal device according to claim 3, wherein gas can be transferred from the liquid crystal composition to a gas absorbing portion provided in a non-pixel portion, but the liquid crystal composition can be transferred from the gas absorbing portion. A liquid crystal element characterized in that gas cannot be transferred to the liquid crystal element. 7. The liquid crystal device according to claim 1, wherein at least one of said pair of substrates is made of a polymer film.