JPH0293425A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To prevent the deformation of a liquid crystal cell and to prevent the deterioration of a picture quality by constituting a supporting member of the liquid crystal cell of a rigid body, and inserting and fixing the liquid crystal cell through an elastic member between the supporting members. CONSTITUTION:The upper frame 3 and the lower frame 4 for fixing a ferroelectric liquid crystal cell 1 are constituted of a rigid body which is scarcely deformed against a mechanical external load, for instance, metallic die casting. Also, between the upper and the lower frames 3, 4, the liquid crystal cell 1 is inserted and held through a rubber member 6 and clamped and fixed with plural acrews 5. Subsequently, by executing heating, heat retaining and slow cooling, an orientation processing of the liquid crystal cell is executed. Accordingly, the liquid crystal is protected from a mechanical external load, and no distortion is given to the cell, therefore, the deterioration of the orientation is suppressed to the minimum and the deterioration of the picture quality can be prevented.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a liquid crystal device that displays images.

[Prior Art] Conventionally, a liquid crystal cell in a liquid crystal device has been fixed by a method as shown in FIG. In the figure, 30 is a cell filled with liquid crystal, 31 is a circuit board for electrically driving the liquid crystal cell 30, 32 is an upper polarizing plate, 33 is a lower polarizing plate, and 34
35 is a backlight; 36 is a frame that fixes the liquid crystal cell 30 and the upper polarizing plate 31; 37 is a rubber connector that electrically connects the liquid crystal cell 30 and the circuit board 31 to the backlight 35; This is the bent part of the frame 36 for connecting the two.

[Problems to be Solved by the Invention] However, the above-mentioned conventional liquid crystal cell fixing method relates to a nematic liquid crystal cell, and when a strongly electrolytic liquid crystal (hereinafter referred to as FLC) cell is fixed by the same method. However, there are various problems described below, and currently there is no optimal method for fixing FLC cells. In other words, when an FLC cell is fixed using the method shown in Fig. 13, (1) fixing the liquid crystal cell will cause considerable distortion to the liquid crystal cell, resulting in a change in orientation and deterioration of image quality. wake up

(2) Compared to nematic liquid crystals, if even a much smaller shock or vibration is transmitted to the liquid crystal cell, the orientation will change and image quality will deteriorate.

(3) FLC liquid crystals are highly temperature dependent, and the temperature distribution within the liquid crystal cell surface is disturbed due to heat generation from the liquid crystal cell itself, heat generation from the circuit board, heat generation from the backlight light source, etc., making it impossible to display images partially. .

There was a drawback.

[Means for Solving the Problems] According to the present invention, in order to solve the above-mentioned problems, a rigid body is used as the fixing structure of the liquid crystal cell, which is difficult to apply distortion to the liquid crystal cell due to an external load. There is.

According to a preferred embodiment of the present invention, the fixed structure is made of a rigid body that does not easily deform under mechanical external loads, has a large heat capacity, and is capable of eight lines of resonant frequency, such as a die-cast metal, as the upper part of the liquid crystal cell. The liquid crystal cell is placed at the bottom of the rigid body, and the liquid crystal cell is sandwiched between the elastic rubber members, and the upper and lower parts of the rigid body are tightened with a plurality of screws.Then, the alignment of the liquid crystal cell is controlled using heat.

[Function] Therefore, according to the present invention, it is possible to reliably hold the liquid crystal cell in a stable state, and since no distortion is applied to the fixed liquid crystal, there is no change in orientation due to deformation or deterioration of the image after fixation. do not have. Further, according to the preferred embodiment,
The liquid crystal cell's resistance to 'iLN, stability, and assembly productivity can be improved, and the environmental temperature conditions for use can be relaxed.

Furthermore, by using a rigid body with high thermal conductivity and large heat capacity, such as metal die-casting, it is possible to equalize the temperature distribution within the plane of the liquid crystal cell with regard to temperature dependence, which is expected to improve image quality. .

[Example] Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a sectional view of a liquid crystal display device according to a first embodiment of the present invention. FIG. 2 is a perspective view of the liquid crystal display device of FIG. 1. In the figure, 1 is a liquid crystal cell for displaying images, 2
1 is a circuit board for electrically driving the liquid crystal cell 1; 3 is an upper frame having sufficient heat capacity and rigidity to hold the liquid crystal cell 1; 4 is a sufficient heat capacity for receiving the liquid crystal cell and the circuit board 2; 5 is a screw for connecting the upper frame 3 and lower frame 4, and 6 is an elastic member with a buffering effect between the liquid crystal cell 1 and the upper frame 3 and between the liquid crystal cell 1 and the lower frame 4. The rubber member 7 is an insulating plate for preventing an electrical short between the circuit board 2 and the lower frame 4, and 8 is a backlight for illuminating the liquid crystal cell 1.

FIG. 3 shows the manufacturing process of the liquid crystal display device of FIG. 1. In the figure, 1 is a liquid crystal cell in which liquid crystal has been injected and sealed, 2 is a circuit board for driving the liquid crystal cell, 3 is an upper frame that is a rigid body for fixing the liquid crystal cell 1, and 4 is a liquid crystal cell. A lower frame is a rigid body on which the cell 1 is placed; 5 is a screw for tightening the upper frame 3 to the lower frame 4 by sandwiching the liquid crystal cell 1; and 8 is a backlight for illuminating the liquid crystal cell 1. Further, 10 is an oven for orientation control processing.

In FIG. 3, (a) shows a state in which the liquid crystal cell 1 is completed;
(b) shows a state in which the circuit board 2 is bonded to the liquid crystal cell 1; (
C) is a cell fixing process for fixing the liquid crystal cell 1 to the upper and lower frames 3.4, (d) is an alignment control process for removing disordered alignment of the fixed liquid crystal cell l, and (e) is a cell fixing process for fixing the liquid crystal cell 1 to the upper and lower frames 3.4. The backlight installation is a completion process in which the circuit board 2 is fixed to the upper and lower frames 3.4 and the backlight 8 is attached to the completed liquid crystal cell fixing structure to complete the liquid crystal display device.

Next, the features of this first embodiment will be explained.

FIG. 4 is a sectional view of an electronic device, such as a word processor (hereinafter referred to as word processor), equipped with a liquid crystal display device having the liquid crystal cell fixing structure shown in FIG. In the same figure,
11 is the liquid crystal display device shown in FIG. 1; 12 is the liquid crystal display device 11;
13 is a control and memory section of the word processor, 14 is a power supply section of the word processor, 15 is a manual calculation section of the word processor, 16 is a window for protecting the liquid crystal display device 11, 17 is an operation button of the word processor, 18 is a This is an outer case for a word processor to protect the entire word processor and to fix the liquid crystal display device 11.

Since the outer case 18 is made of an elastic plastic material, it has a buffering effect against static mechanical external forces, but is susceptible to deformation. However, since the lower frame 4 of the liquid crystal display device 11 shown in FIG.
The liquid crystal cell 1 can maintain the flatness of the initial state.

Next, vibration resistance as a dynamic mechanical external load will be explained. Vibration from the outside, for example, vibration during transportation, is generally around 10 Hz to 100 Hz, but resonance occurs between the outer case 18 and the lower frame 4, which are subjected to this imaging acceleration. Similarly, resonance occurs between the lower frame 4 and the liquid crystal cell 1.

In this case, since the lower frame 4 is a rigid die-cast metal body, the resonance point at which the maximum acceleration occurs will well exceed 100 Hz, and as a result, the acceleration applied to the liquid crystal cell 1 will be attenuated.

Next, uniformization of heat will be explained. Figure 5(a)-(
C) shows the temperature distribution when the upper and lower frames 3.4 are made of a material that is difficult to conduct heat. Heat sources can be broadly classified into: (1) self-heating inside the liquid crystal cell during driving, (2) heat generation in the drive circuit section, and (2) heat generation from the lamp light source in the backlight. Of these, (1) self-heating and (2) heat generation in the drive circuit section cannot be evaluated separately, but it is (2) heat generation in the drive circuit section that has a large effect on the temperature distribution within the surface of the liquid crystal cell. In the drive circuit section, the temperature rise is greater than the surface temperature of the liquid crystal cell, and the temperature difference is large. Therefore, within the liquid crystal cell 1, as shown in FIG. Temperature unevenness occurs. The heat generated inside the liquid crystal cell 1 is mainly caused by Joule heat due to the polarization reversal current flowing through the electrodes inside the liquid crystal cell when switching images, but the amount of heat is small and the generated heat is thermally conducted within the surface of the liquid crystal cell. Since it is transmitted almost uniformly, the influence on the temperature distribution within the surface of the liquid crystal cell is negligible. Next, (2) the temperature distribution due to heat generation of the lamp light source 43 in the backlight 8 is shown in FIG. 5(b). The temperature distribution within the plane of the liquid crystal cell changes depending on the position of the lamp 43, but since the amount of heat generated near the electrodes at the end of the lamp occupies most of the heat, the peripheral area within the plane of the liquid crystal cell becomes high temperature. From the above, the temperature distribution of all of these heat generation sources becomes as shown in FIG. 5(C), and the temperature distribution within the surface of the liquid crystal cell becomes large. For this reason, the driving voltage,
In FLCs whose driving conditions such as driving frequency are highly dependent on temperature, it becomes difficult to display a uniform image over the entire surface of the liquid crystal cell, resulting in significant deterioration of image quality.

However, in the liquid crystal display device shown in Fig. 1, the upper and lower frames 3.4, which are metal members with high heat transfer coefficient and heat capacity, are arranged around the liquid crystal cell 1, so the temperature distribution within the liquid crystal cell surface is significantly reduced. As a result, as shown in FIG. 5(d), the image is almost uniform, and good image quality can be obtained.

Next, the manufacturing process shown in FIG. 3 in this first embodiment will be explained.

FIG. 6(a) is an enlarged view of a cross section of a liquid crystal cell. In the figure, 21 is a strongly conductive liquid crystal, and 22 is a liquid crystal 21.
The thickness is 1.4 μm to maintain the gap from both sides at 1.4 μm.
1 mm glass substrate, 23 is ITO (In203-3nO2) with a film thickness of about 1500 to drive the liquid crystal 21.
The electrode film 24 has a thickness of about 1 mm to maintain the orientation of the liquid crystal 21.
This is an alignment film for 00 people.

During the manufacturing process shown in FIG. 3, the liquid crystal cell 1 is completed by injecting the liquid crystal 21 between the glass substrates 22 as shown in FIG. 3(a), and the circuit board 2 is completed as shown in FIG. 3(b). At the time of joining, the liquid crystal 21 of the liquid crystal cell 1 has a regular layer structure as shown in FIG. 6(a). However, after assembling the liquid crystal cell 1 into the structure shown in FIG. 1 transforms and the 6th
As shown in Figure (b), the layer of liquid crystal 21 collapses. If an image is displayed in this state, the regular movement of the liquid crystal 21 will be impaired and good image quality will not be obtained. Therefore, this first
In this embodiment, after assembling the liquid crystal cell fixing structure shown in FIG. 3(c), heat treatment is performed in an oven 10 as shown in FIG. 3(d). As a result, the liquid crystal 21
A regular layered structure is again formed as shown in Figure (c).

When an image is displayed in this state, the liquid crystal 21 is regularly controlled and a good image quality is displayed.

Finally, the arrangement of screws and the elastic rubber member for fixing the liquid crystal cell, which are features of the first embodiment, will be explained. FIG. 7 is a plan view of the liquid crystal display device of this embodiment. In this figure, members common to those in FIG. 1 are given the same reference numerals.

That is, 3 is a rigid upper frame for holding down the liquid crystal cell 1 to the lower frame 4 using a screw 5 via an elastic rubber member 6, and 5 is a rigid upper frame for holding the liquid crystal cell 1 to the upper frame 3 via a rubber member 6. Screws to be tightened from above; 1 is a liquid crystal display panel (liquid crystal cell) that displays an image; 6 is a screw located between the lower frame 4 and liquid crystal cell 1 and between the upper frame 3 and liquid crystal cell 1; It is a flat rubber member that has a cushioning effect against the air.

In the liquid crystal cell fixing process shown in FIG. 3(C), by tightening the screw 5, force is applied to the liquid crystal cell 1 through the rubber member 6, causing distortion in the liquid crystal cell 1. When distortion occurs, the liquid crystal 21 in the liquid crystal cell 1 enters the state shown in FIG. 6(b), and the image quality of the liquid crystal cell 1 tends to deteriorate. In particular, when distortion occurs in a ferroelectric liquid crystal cell, alignment film failure such as sanded texture, which causes switching failure, is likely to occur, and in this case, as described above, an accurate image cannot be displayed on the liquid crystal cell 1. Therefore, here, in order to apply force to the liquid crystal cell 1 as evenly as possible and suppress distortion to a small level, the plurality of screws 5 are positioned approximately symmetrically with respect to the center of the liquid crystal cell 1 and at approximately equal intervals. Even after the liquid crystal cell 1 is installed in a device, there is a possibility that distortion may be applied to the liquid crystal cell 1 due to impact, etc. applied to the device. Since it is made of material, almost no distortion occurs in the casing, and the resonance point shifting effect of the rigid upper and lower frames 3.4 and the buffering effect of the rubber member 6 sufficiently attenuate vibration shocks to the equipment. After that, the distortion is transmitted to the liquid crystal cell 1, so that the distortion of the liquid crystal cell 1 can be suppressed to a small level.

[Other Embodiments] FIG. 8 shows a second embodiment of the present invention. In the figure, members with the same reference numerals as in FIG. 1 are the same members as in FIG. 1.

40 is an adhesive for fixing the liquid crystal cell 1. By removing the upper frame 3, screws 5, etc. in this manner, it is possible to reduce the height and weight of the liquid crystal display device.

FIG. 9 shows a third embodiment of the invention. In the diagram, 1 to 4
The structure up to 0 is the same as that in FIG. 41 is lower frame 4
It is a heat dissipation fin processed on the surface. This results in
It is possible to promote heat dissipation.

FIG. 10 shows a fourth embodiment of the invention. In the figure, 1 to 8 have the same structure as in Figure 1, but the positions of the circuit board 2 and insulating plate 7 are changed, and a part of the rubber member 6
The rubber connector has been changed to 2. According to the configuration shown in FIG. 10, it is possible to simplify the structure and reduce costs.

FIG. 11 shows a fifth embodiment of the invention. In the figure, 43 is a lamp built into the backlight 8, and 44 is a lamp 4.
This is the electrode section of No. 3. When the amount of heat generated from the lamp electrode part 44 is large, a part of the lower frame 4 is cut out to thermally connect the lamp electrode part 44 and the lower frame 4, and the heat is guided to the lower frame 4, thereby reducing the liquid crystal cell. It becomes possible to reduce the temperature unevenness described in No. 1.

FIG. 12 shows a sixth embodiment of the invention. In the figure, 45 is a frame made of a shape memory alloy and stores the state in which the liquid crystal cell 1 is sandwiched therein, and 46 is a portion of the frame 45 where the liquid crystal cell 1 is sandwiched. When the liquid crystal cell 1 and circuit board 2 are assembled in the state shown in FIG. 12(a) and placed in a temperature environment in which the shape is memorized, the frame 45 is deformed to the memorized state shown in FIG. 12(b), and the liquid crystal cell 1 is Pinch firmly. Here, if the temperature at which the shape is memorized and the temperature at which the liquid crystal cell 1 is subjected to the alignment control process are matched, it is possible to sandwich the liquid crystal cell 1 and perform the alignment control process in one step, which is reasonable.

[Effects] As explained above, according to the present invention, (1) the deformation of the liquid crystal cell from mechanical external loads during assembly can be prevented, so the image quality does not deteriorate; therefore, the ferroelectric liquid crystal cell can be reliably assembled; Can be fixed.

■Reliability is improved because alignment deterioration of liquid crystal cells can be minimized due to shocks and vibrations that occur during transportation or use of liquid crystal display devices.

■Liquid crystal display devices can be installed in products that are subject to harsh conditions and are susceptible to shock and vibration, such as portable word processors.

■ Transportation conditions for liquid crystal display devices, such as packaging specifications, can be simplified.

■The operating temperature environment for products equipped with liquid crystal display devices can be relaxed.

■ Internal heat generation can be made uniform on the liquid crystal cell surface, eliminating the need for other heat dissipation parts and making the liquid crystal display device more compact.

■If the image quality of the liquid crystal cell deteriorates due to external impact after the liquid crystal display device is installed in a word processor, television, etc., reorientation processing can be performed while it is assembled in the case, improving serviceability.

Effects such as this can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of a liquid crystal display device according to a first embodiment of the present invention, FIG. 2 is a perspective view showing the structure of the liquid crystal display device of FIG. 1, and FIG. Fig. s1 is a manufacturing process diagram showing the manufacturing process of the liquid crystal display device, Fig. 4 is a cross-sectional view of a word processor equipped with the liquid crystal display device of Fig. 1, and Fig. 5 (a), (b), and (c) are Figure 5 (d) shows the in-plane temperature distribution diagram due to the heat exerted by each heat generation source when the display device is in operation, without taking into account the heat radiation from the liquid crystal cell. Temperature distribution diagram, Figure 6 is an enlarged cross-sectional view showing changes in the layer structure of a strong-voltage liquid crystal cell, Figure 7 is a plan view of the liquid crystal display device in Figure 1, and Figures 8 to 1.
2 is a sectional view showing the structure of a liquid crystal display device according to another embodiment of the present invention, and FIG. 13 is a sectional view showing the structure of a conventional liquid crystal display device. 1: Liquid crystal cell, 2: Circuit board, 3: Upper frame, 4: Lower frame, 5: Screw, 6: Rubber member, 7: Insulating plate, 8: Backlight, 10: Orientation control oven, 11: Liquid crystal display device, 12: controller section, 13: memory section, 14: power supply section, 15: input calculation section, 16: window, 17: operation button, 18 two cases, 21: liquid crystal, 22 glass plate, 23: ITO film , 24: Alignment film, : Liquid crystal cell of conventional example, : Substrate of conventional example, : Upper polarizing plate of conventional example, : Lower polarizing plate of conventional example, : Rubber connector of conventional example, : Backlight of conventional example, : Conventional frame, : Conventional frame bent part, : Adhesive, : Heat dissipation fin, : Rubber connector, : Lamp, Electrode part of two lamps, : Shape memory alloy frame, : Sandwiched part. Diagram

Claims (15)

[Claims] (1) A liquid crystal display device for displaying images, characterized in that the supporting member of the liquid crystal cell has a rigid structure that does not easily distort the liquid crystal cell due to external loads. (2) The liquid crystal display device according to claim 1, wherein the support member uses a metal block or metal die-cast as a rigid body, and is fixed by sandwiching an elastic member in a portion that directly touches the liquid crystal cell. (3) A claim characterized in that after the liquid crystal cell is fixed to a metal block or a metal die-cast support member with an elastic member sandwiched therebetween, orientation control processing of the liquid crystal cell is performed, such as heating, heat retention, and slow cooling. Item 2. The liquid crystal display device according to item 2. (4) The rigid body is divided into an upper part and a lower part of the liquid crystal cell, and after sandwiching the liquid crystal cell and the elastic member, the liquid crystal cell is fixed by tightening the upper part and the lower part of the rigid body with a plurality of screws. The liquid crystal display device according to claim 2. (5) Claim 4, wherein the screws are arranged approximately symmetrically and at equal intervals with respect to the center of the liquid crystal cell.
The liquid crystal display device described. (6) The liquid crystal display device according to claim 4, wherein the lower part of the rigid body is provided with a fixed part for a backlight that illuminates the liquid crystal cell. (7) The liquid crystal display device according to claim 2, wherein the rigid body is a member having sufficient heat capacity. (8) The liquid crystal display device according to claim 2, wherein the rigid body is made of a material that can shift the vibration resonance point of the liquid crystal cell to a frequency sufficiently higher than the frequency of vibrations applied to the liquid crystal display device from the outside. . (9) The liquid crystal display device according to claim 2, wherein a rubber adhesive is used as the elastic member. (10) The liquid crystal display device according to claim 2, wherein a radiation fin is integrally provided on the rigid body. (11) The liquid crystal display device according to claim 2, wherein a rubber connector is used for the elastic member. (12) The liquid crystal display device according to any one of items 1 to 11, wherein the rigid body is a shape memory alloy. (13) The liquid crystal display device according to any one of claims 1 to 11, wherein the liquid crystal is a ferroelectric liquid crystal. (14) The liquid crystal display device according to claim 12, wherein the liquid crystal is a ferroelectric liquid crystal. (15) The liquid crystal display device according to claim 13 or 14, wherein the ferroelectric liquid crystal is a chiral smectic liquid crystal.