JPH06102494A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which can maintain a specified display grade regardless of a use environmental temp. CONSTITUTION:This liquid crystal display device has a liquid crystal cell constituted by injecting a liquid crystal A from a liquid crystal encapsulating port 5 into the thin liquid crystal encapsulating space defined by a pair of glass plates 2, 3 facing each other via the thin space and a sealing member 4 which adheres the inside surfaces in the peripheral parts of two sheets of these glass plates 2, 3 by remaining the liquid crystal encapsulating port 5, then, sealing the liquid crystal encapsulating port 5. The above-mentioned liquid crystal display device is provided with a compressive fluid B encapsulating region outside a display region 6 in the liquid crystal encapsulating space.

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 device.

[0002]

2. Description of the Related Art A liquid crystal display device of this type includes two glass plates which are opposed to each other with a minute gap therebetween. These two glass plates are arranged opposite to each other by adhering the inner peripheral portions thereof to each other with a sealing member. The sealing member is provided in a strip shape on the inner peripheral portions of both glass plates, leaving a discontinuous portion capable of functioning as a liquid crystal sealing port. In addition, a transparent electrode corresponding to the display pattern is provided on the inner surface of each glass plate. A predetermined liquid crystal is enclosed in a thin liquid crystal enclosure space formed between two glass plates. When an electric potential is applied between the electrodes, the molecular orientation of the liquid crystal existing between the electrodes changes, so that the liquid crystal does not transmit light from the state of transmitting light corresponding to the display pattern of the transparent electrode. The state changes from a state in which light is not transmitted to a state in which light is transmitted. In this way, the display surface of this liquid crystal display device is driven to display positively or negatively according to the display pattern formed by the transparent electrodes.

By the way, the liquid crystal is sealed in the thin liquid crystal sealed space between the two glass plates by the sealing member surrounding the inner surfaces of the two glass plates, leaving the liquid crystal sealing port as described above. The sealing port of the liquid crystal cell adhered in a strip shape is brought into contact with the liquid crystal in a vacuum state, and the external pressure is increased. After the liquid crystal is filled, the liquid crystal filling port is sealed with a sealing material such as an ultraviolet curable resin. Therefore, the liquid crystal once enclosed in the thin liquid crystal enclosure space between the two glasses never leaks to the outside.

In order to achieve an appropriate display state, the distance between both glass plates, that is, the clearance of the liquid crystal filled space must be constant over the entire liquid crystal cell. Therefore, the liquid crystal filled space is filled with the liquid crystal. At the same time, hard resin fibers or beads called spacers are dispersed and mixed. The thickness of the liquid crystal-filled space is generally about 1 to 10 μm. Therefore, the spacer is beads having a particle diameter equivalent to that of the spacer or a hard fiber having a wire diameter. By doing so, even if an external force that brings the two glass plates closer to each other is applied, the thickness of the liquid crystal enclosed space does not shrink irregularly, and the glass plates are elastically elastic by a temporary external force. Even if the flexure occurs, the spacer returns to its original state due to the repulsive action of the spacer.

As described above, the spacer plays a role of preventing the thickness of the thin liquid crystal enclosure space from being reduced.

Conventionally, the liquid crystal display device having the above-mentioned general structure has the following problems. When used in extremely cold places or extremely cold places, the volume of the internal liquid crystal shrinks, but the spacer prevents the reduction of the space between both glass plates as described above. A pressure is generated, which causes the volatile substances contained in the liquid crystal to evaporate and appear as bubbles in the liquid crystal enclosed space. Once the volatile substance dissolved in the liquid crystal becomes bubbles as described above, it does not dissolve in the liquid crystal again even if the temperature rises to room temperature.

As described above, this type of liquid crystal display device is
Proper display is possible only when liquid crystal is present between the transparent electrodes on the inner surfaces of both glass plates.If bubbles are generated between the electrodes of both glass plates, proper display drive is performed at this part. I will not be able to.

On the other hand, when a liquid crystal display device of this type is used in a high temperature atmosphere, the liquid crystal enclosed therein undergoes volume expansion, contrary to the above. The above spacers, which are distributed and purchased in the liquid crystal, are effective in preventing the distance between the two glass plates from shrinking, but do nothing to prevent the distance between the two glass plates from increasing. Absent. Therefore, when the internal liquid crystal expands in volume under a high temperature atmosphere, the gap between the two glass plates expands accordingly. Both glass plates are adhered to each other by a sealing member around the inner surfaces thereof, and the distance between the peripheral parts does not increase, but both glass plates bend in the central part of the display part, As a result, the thin liquid crystal-filled space is deformed to bulge like a drum in the central portion.

As a result, a density difference in display occurs between the central portion where the thickness is increased and the peripheral portion where the thickness is not so increased, which means that the display quality is lowered in a high temperature state. To do.

The present invention has been devised under the above circumstances, and it is an object of the present invention to provide a liquid crystal display device capable of maintaining a constant display quality regardless of changes in ambient temperature. That is the subject.

[0011]

In order to solve the above problems, the present invention takes the following technical means. That is, the invention described in claim 1 of the present application is a sealing method in which two glass plates facing each other through a thin space and the inner peripheral surfaces of the two glass plates are bonded to each other with a liquid crystal sealing port left. A liquid crystal display device comprising a liquid crystal cell, which is formed by injecting liquid crystal from the liquid crystal filling port and then sealing the liquid crystal filling port into a thin liquid crystal filling space defined by a member. Is characterized in that a gas sealed area is provided outside the display area.

According to a second aspect of the present invention, in the liquid crystal display device according to the first aspect, the compressive fluid sealing region communicates with the liquid crystal sealing port and has a long shape extending to the liquid crystal sealing space. The passage is provided by extending a sealing member that adheres the inner surfaces of the peripheral portions of the both glass plates in an inward band shape, and is provided by enclosing gas in a part of the passage. I am trying.

Further, the invention described in claim 3 of the present application is, in the liquid crystal display device according to claim 1 or 2, characterized in that the fluid sealed in the compressive fluid sealing region is an inert gas. .

Further, in the invention described in claim 4 of the present application, in the liquid crystal display device according to claim 1 or 2, the fluid sealed in the compressible fluid sealing region is a compressible liquid made of a polymer material. It is characterized by that.

[0015]

In the liquid crystal display device of the present invention, a compressive fluid is basically enclosed together with the liquid crystal in the liquid crystal enclosure space between the two glass plates. The volume of the compressive fluid changes relatively easily with the change in pressure. For example, when the liquid crystal display device of the present invention is used in an extremely low temperature atmosphere, the volume of liquid crystal in the enclosed space is reduced. However, since the compressive fluid expands in volume by the volume reduction of the liquid crystal, the pressure inside the liquid crystal enclosed space is abnormally lowered and the volatile substances contained in the liquid crystal are vaporized as in the conventional case. It won't happen.

The thickness of the liquid crystal enclosed space is 1 to 10 μm.
It is as thin as m, and the liquid crystal in this space is
Since the spacers are dispersed and mixed, the liquid crystal does not flow in the liquid crystal filled space. In other words, the compressible fluid sealed in the liquid crystal sealed space does not inadvertently move in the space toward the display surface.

Therefore, by placing the compressible fluid arranged in the liquid crystal-filled space as described above outside the display area, the area occupied by the compressible fluid is slightly expanded or contracted even when the temperature changes. Therefore, the display function does not cause any hindrance.

Contrary to the above, when the liquid crystal display device of the present invention is used in a high temperature atmosphere, even if the liquid crystal in the enclosed space expands in volume, the expanded portion is compressed in advance in the enclosed space. The volatile fluid is only compressed to reduce its volume, and the pressure in the liquid crystal filled space does not become abnormally high. Therefore, even when used in a high temperature atmosphere, it is possible to effectively avoid the situation where the space inside the liquid crystal-filled space bulges like a drum in the central portion as in the conventional example. As a result, it is possible to avoid the deterioration in display quality that has conventionally occurred when used in a high temperature atmosphere.

According to the second aspect of the present invention, when the region in which the compressive fluid is to be enclosed is limited by extending the sealing member for adhering the two glasses, the region in which the compressible fluid is enclosed is defined. It is possible to more surely standardize, and it is possible to effectively avoid a situation in which the compressive fluid sealed in the liquid crystal sealed space together with the liquid crystal is located in, for example, the display region.

By adopting an inert gas such as nitrogen or argon as the compressive fluid, it is possible to prevent deterioration of the liquid crystal in the cell and ensure the life of the device.

As described above, according to the liquid crystal display device of the present invention, the excellent effect that the display quality can be made constant regardless of the temperature of the use atmosphere is exhibited. Moreover, the structure is basically very simple in that a certain amount of the compressive fluid is enclosed together with the liquid crystal in the thin liquid crystal enclosure space of the conventional liquid crystal display device. Does not include factors of increase.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be specifically described below with reference to the drawings. 1 and 2 show a first embodiment of a liquid crystal display device 1 of the present invention.

Two glass plates 2 and 3 having a predetermined thickness are adhered to each other with a sealing member 4 interposed therebetween. The sealing member 4
The two inner surfaces of the glass plates are bonded to each other in a band shape to form a liquid crystal sealing port 5 in which a part of the glass plate is a non-existing portion. For this sealing member 4, for example, a resinous adhesive material can be used. By mixing a space holding member similar to a spacer described later into this resinous adhesive material, the sealing member can be formed as described above. When the glass plates are interposed, the two glass plates are pressed against each other with a predetermined force, so that the distance between the two glass plates 2 and 3 can be made constant.

The thickness of each glass plate 2 and 3 is, for example,
It can be 1.1 mm, and both glass plates 2, 3
The gap between them can be, for example, 1 to 10 μm. That is, 1 to 10 are included in the sealing member 4.
This means that a spacing member made of beads or hard resin fibers having a particle diameter or wire diameter of μm is mixed.

On the inner surfaces of both glass plates 2 and 3, the same structure as before is added to achieve the function as a display device. That is, transparent electrodes (not shown) for cooperating to achieve a display pattern are arranged on the inner surfaces of the glass plates 2 and 3. Further, when the display action is performed by a so-called twisted nematic, both glass plates 2,
3, the molecular orientations of the liquid crystal near the inner surface are
° Minute grooves (slits) are formed so that they intersect.

When an electric potential is applied between the transparent electrodes on the inner surfaces of the glass plates 2 and 3, the molecular orientation of the liquid crystal located between the electrodes can be changed.
Although not shown, a deflector or a reflector is appropriately arranged on the outer surface of the glass plates 2 and 3.

In FIG. 1, the area surrounded by a dot-dash line is the display area 6. Therefore, by patterning the transparent electrodes in this display area 6, the pattern to be displayed is formed.

In the present embodiment, a band-shaped passage 7 extending from the liquid crystal filling port 5 to the display area 6 is formed. This passage 7 can be formed by inwardly extending the sealing member 4 for bonding the two glass plates 2 and 3 to each other. In this embodiment, the extending portions 4a and 4b are alternately extended from the sealing member on the upper side and the sealing member on the lower side in a band shape, so that the sealing port 5 communicates with the display area in a zigzag shape. A strip-shaped passage 7 is formed.

Liquid crystal is sealed from the sealing port 5 in the thin liquid crystal sealing space sandwiched between the glass plates 2 and 3 of the liquid crystal display device formed as described above. The liquid crystal is filled in a vacuum container and evacuated, and in that state, the liquid crystal is brought into contact with the filling port, and then the pressure in the vacuum container is returned to atmospheric pressure. Then, the liquid crystal is filled into the liquid crystal filling space from the filling port 5 while being pressed by the external pressure. In the first place, the liquid crystal filled space is in a vacuum state when the vacuum container is evacuated, so that the liquid crystal brought into contact with the sealed port 5 in that state fills the display area sequentially through the passages 7. To be done. As long as this is done, unnecessary bubbles do not enter the display area.

Thus, in the present invention, the liquid crystal is not filled in all the spaces in the liquid crystal cell, but the liquid crystal to be injected is released from the sealing port 5 at the final stage of the liquid crystal filling operation, and Instead, a compressive fluid, eg, an inert gas such as nitrogen or argon, is contacted with the fill port. Then, as shown in FIG. 1, in the passage 7, the liquid crystal A is followed by the inert gas B.
Will be enclosed.

Finally, the liquid crystal filling port 5 is sealed with an ultraviolet curable resin or the like.

In the above structure, the liquid crystal cell is filled with the display region 6 and the liquid crystal A fills about half of the passage 7, and the half of the passage 7 on the sealing side is filled with the inert gas B.
Will be satisfied.

When the liquid crystal is filled in the cell as described above, the space holding members between the two glass plates called spacers are dispersedly arranged in the liquid crystal, as in the conventional case. The spacers can be dispersed and mixed as described above by spraying the spacers on the inner surface of one or both of the glass plates in advance or by mixing them in the liquid crystal.

When the liquid crystal display device having the above structure is used, for example, in an extremely low temperature atmosphere, the liquid crystal contracts in volume, but in this case, in the present invention, a compressible fluid is sealed in the cell. Therefore, it is possible to effectively prevent the compressive fluid from expanding due to the contraction of the liquid crystal, and thus the pressure of the liquid crystal in the cell to be abnormally lowered.

In the embodiment of FIG. 1, the boundary line C between the liquid crystal A and the compressive fluid B in the passage 7 is leftward in FIG. Only by moving inward of the passage 7, it is possible to effectively prevent an abnormal decrease in the cell internal pressure.

Therefore, when the liquid crystal in the liquid crystal cell contracts in volume under use in an extremely low temperature atmosphere as in the prior art, since the volume of the liquid crystal enclosed space is defined by the spacer, the space inside the enclosed space is limited. The pressure drops abnormally,
Therefore, it is possible to effectively solve the problem that the volatile substance mixed in the liquid crystal evaporates to form bubbles, which hinders the display function.

As in this embodiment, if the region in which the compressive fluid B is to be sealed is defined in the elongated passage 7 extending from the sealing port 5, the region occupied by the compressible fluid can be made uniform. It is possible to effectively avoid such a situation that the compressive fluid inadvertently enters the display area 6 and hinders the display function.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the compressive fluid sealing passage 7 is arranged on the opposite side of the liquid crystal sealing port 5. The compressive fluid sealing passage 7 of this example is also formed in a band shape by extending the sealing member 4 for adhering both glasses inward. It is preferable that an inert gas such as nitrogen or argon is sealed in the compressive fluid sealing passage as in the above-described embodiment.

In the case of the present embodiment, the inert gas and the liquid crystal may be sealed in the cell as follows, for example.

First, the vacuum container is filled with an inert gas, and then the container is evacuated. In this case, the vacuum is not evacuated to an absolute vacuum, but a certain amount of diluted inert gas is present in the vacuum container.

At this time, a low-pressure inert gas close to a vacuum also enters the liquid crystal cell. Then, next, the liquid crystal is brought into contact with the liquid crystal sealing port 5, and the pressure in the vacuum container is increased. Then, the liquid crystal sequentially enters the liquid crystal enclosure space from the enclosure port 5 while being pressed by the external pressure. As a result, as shown in FIG. 3, the inert gas B is pushed into the passage 7 and the liquid crystal A fills the rest of the passage or the display area.

Then, finally, the liquid crystal filling port is sealed with an ultraviolet curable resin or the like.

It will be apparent that the liquid crystal display device having this structure also has the same effects as the first embodiment.

Further, FIG. 4 shows a third embodiment of the present invention. This embodiment does not intentionally provide a passage, as found in the first and second embodiments above, to clearly define the compressible fluid containment region. However, the liquid crystal filling port 5 is set at the end portions of the sides of the rectangular glass plates 2 and 3, whereby the liquid crystal filling port 5 is formed.
Will be set at the corner of the liquid crystal enclosed space 8.

The operation of filling the liquid crystal and the inert gas into the cell having such a structure may be the same as that described in the first embodiment.

As a result, an inert gas B is filled in the area near the liquid crystal filling port 5, and liquid crystal A is filled in all other areas.

Even if this is done, the liquid crystal enclosed space 8
In the first place, the liquid crystal A has a thin thickness of about 1 to 10 μm and the spacers are dispersed and mixed in the liquid crystal, so that the liquid crystal A does not flow in the liquid crystal enclosure space 8. That is, the inert gas once sealed near the liquid crystal sealing port as described above rarely moves carelessly in the liquid crystal sealing space.

Therefore, even if the inert gas encapsulation region is expanded most in the cryogenic state, the expanded inert gas encapsulation region is expanded even in anticipation of the expected change in the size of the inert gas encapsulation region due to the temperature change. The amount of the inert gas to be sealed or the position of the display region 6 may be set in advance so that the sealed region does not invade the display region 6.

As described above, in the liquid crystal display device of the present invention, the compressible fluid is enclosed in the liquid crystal enclosure space together with the liquid crystal while the position of the liquid crystal is substantially limited. Also in the, even if the temperature of the liquid crystal sealed space is abnormally lowered, or the thickness of the liquid crystal sealed space is irregularly expanded and the display quality is not deteriorated, even under any temperature environment, A certain display quality can be achieved.

Of course, the scope of the present invention is not limited to the above embodiments. In particular, various methods of setting the compressible gas-filled region other than the above-described embodiment are possible.

Further, as the compressive fluid, a polymer material or the like can be adopted in addition to gas.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line II-II in FIG.

FIG. 3 is a plan view of a second embodiment of the present invention.

FIG. 4 is a plan view of a third embodiment of the present invention.

[Explanation of symbols]

 1 Display Device 2, 3 Glass Plate 4 Sealing Member 5 Liquid Crystal Filling Port 6 Display Area 7 Passage 8 Liquid Crystal Filling Space A Liquid Crystal B Compressible Fluid

Claims (4)

[Claims] 1. A thin shape defined by two glass plates facing each other across a thin space, and a sealing member for bonding inner peripheral surfaces of these two glass plates to each other while leaving a liquid crystal sealing port. A liquid crystal display device comprising a liquid crystal cell in which liquid crystal is injected into the liquid crystal sealed space from the liquid crystal sealed port and then the liquid crystal sealed port is sealed. A liquid crystal display device comprising a fluid-filled region. 2. The compressive fluid sealing region is provided with a sealing member for adhering a long passage communicating with the liquid crystal sealing port and reaching the liquid crystal sealing space to inner surfaces of peripheral portions of the both glass plates. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is provided by extending in an inward band shape, and is provided by enclosing a compressive fluid in a part of the passage. 3. The compressible fluid sealed in the compressible fluid sealing region is an inert gas.
Liquid crystal display device. 4. The liquid crystal display device according to claim 1, wherein the compressive fluid sealed in the compressible fluid sealing region is a compressible liquid made of a polymer material.