JPH04256927A - Electrooptic device - Google Patents

Abstract

PURPOSE:To obtain a highly reliable electrooptic device which is subminiaturized and extremely thinned to make the device compact. CONSTITUTION:In the electrooptic device such as a liquid crystal display device where a display element 1 such as a liquid crystal panel and a circuit board 3 which drives and controls the display element are connected electrically through a flexible wiring connection member 4, the circuit board 3 is coupled and held integrally by a holding member 7 at an end part outside the display area R of the display element 1 and a flexible wiring connection member 4 is curved and arranged between the circuit board 3 and display element 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to electro-optical devices such as liquid crystal display devices. More specifically, the present invention relates to an electro-optical device in which a display element such as a liquid crystal panel and a circuit board for driving and controlling the display element are electrically connected via a flexible wiring connection member.

0002

[Prior Art] Conventionally, for example, in a liquid crystal display device,
Display elements such as liquid crystal panels (LCD panels) and PCBs (Print Circuit Boards) that drive and control them
FPC (Flexible
It is known that conductive connection is made using a flexible wiring connection member such as Print Circuit. Particularly recently, so-called COF (C-F), which has integrated circuits such as LSI chips for driving liquid crystals arranged on flexible wiring connection members as mentioned above, has become popular.
(hip on film) is often used (for example, see Japanese Utility Model Application Publication No. 1-88928, which was previously proposed by the present applicant).

FIG. 6 shows a flexible wiring connection member as described above,
In particular, it is a cross-sectional view of a part of a liquid crystal display device showing an example of a conventional electro-optical device using a COF. In the figure, reference numeral 1 denotes a display element such as a liquid crystal panel, and the display element 1 has a structure in which a liquid crystal layer (not shown in the figure) is interposed between a pair of upper and lower electrode substrates 11 and 12 that are substantially rectangular in plan view. Reference numeral 2 denotes a frame body having a rectangular planar shape provided around the display element 1. The frame body 2 is formed in a U-shape in cross section, and a circuit board 3 for driving and controlling the display element 1 is placed inside the frame body 2. 1 and approximately parallel to display element 1
It is provided so as to protrude outward. The circuit board 3 and the display element 1 are conductively connected by a flexible wiring connection member 4 such as FPC, and the connection member 4 is arranged substantially flat between the display element 1 and the circuit board 3. An integrated circuit 5 such as an LSI chip is mounted on the connection member 4. 6
1 is a backlight that illuminates the display element from the back side, and in the case of the figure, it is composed of a light source 6a and a light guide 6b that guides the light from the light source 6a to the back side of the display element.

FIG. 7 shows another conventional example, in which a circuit board 3 is arranged on the back side of the display element 1, especially in the case of the figure, on the back side of the backlight 6, and the circuit board 3 and the display element 1 are connected to each other. The wires are electrically connected by a flexible wiring connecting member 4 bent into a substantially U-shape. The other configurations are substantially the same as in the previous example.

[0005]

However, as in the conventional example shown in FIG. In the case where the flexible wiring connecting member 4 that conductively connects the circuit board 3 and the flexible wiring connecting member 4 are arranged substantially flat without bending, the circuit board 3 and the flexible wiring connecting member 4 protrude greatly to the sides of the display element 1, and the display element There are problems such as the maximum outer circumferential dimension of the entire device being considerably larger than the display area of No. 1. on the other hand,
If the circuit board 3 is arranged on the back side of the display element 1 as in the conventional example shown in FIG. Since it protrudes into the area, it cannot be applied to an OHP projector or the like that transmits light without using a backlight as shown in the figure. In addition, when using a backlight, the backlight 6 must be placed between the display element 1 and the circuit board 3 as shown in the figure, and the backlight 6 and the circuit board 3 must be connected in the thickness direction of the device. There are problems such as overlapping in the vertical direction (in the figure) and the overall thickness of the device. Furthermore, during maintenance such as replacing the backlight, the circuit board 3 must be attached and detached, which makes the work complicated. Moreover, the flexible wiring connection member 4 is
Since one end of the display element 1 is fixed to the display element 1 and the other end is fixed to the backlight 6 via the circuit board 3, which are different members, the reliability of the connection may deteriorate. Furthermore, if there is a limit to the length of the flexible wiring connection member, the backlight cannot be made thicker, and therefore sufficient brightness may not be ensured.

The present invention has been proposed in view of the above-mentioned problems, and an object of the present invention is to provide an electro-optical device that has a compact structure by making the entire device as small and thin as possible and has high reliability.

[0007]

Means for Solving the Problems In order to achieve the above object, an electro-optical device according to the present invention has the following configuration. That is, in an electro-optical device in which a display element such as a liquid crystal panel and a circuit board for driving and controlling the display element are electrically connected via a flexible wiring connection member, a circuit is installed on the edge of the display element outside the display area. The substrate is integrally connected and held by a holding member, and a flexible wiring connection member is bent and arranged between the circuit board and the display element.

[0008]

[Operation] By integrally connecting and holding the display element and the circuit board, which are conductively connected by the flexible wiring connection member as described above, by the holding member, the display element and the circuit board may be inadvertently shifted. The risk of poor connection or the like is reduced as much as possible, and the reliability of the connection by the flexible wiring connection member can be increased. In addition, by bending and arranging the flexible wiring connecting member between the display element and the circuit board, the maximum external dimensions of the device can be minimized, and in the case of a device using a backlight, there is no overlap with the circuit board. Since the device can be placed without wrapping, the thickness of the entire device can be made as thin as possible.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The electro-optical device according to the present invention will be specifically explained below using an example in which it is applied to a liquid crystal display device. FIG. 1 is a plan view of a liquid crystal display device showing an embodiment of an electro-optical device according to the present invention, FIG. 2 is an enlarged longitudinal cross-sectional side view taken along the line A-A in FIG. 1, and FIG. It is a vertical side view showing the configuration, and members having the same functions as those in FIGS. 6 and 7 are designated by the same reference numerals and will not be described again.

In this embodiment, as shown in FIG. 3, a display element 1 and a circuit board 3 are integrally positioned and held at a predetermined distance in parallel with each other via a holding member 7. The member 7 is formed into a substantially plate shape, and has a fixing means 8 such as an adhesive.
The display element 1 is fixed to the back surface of the lower substrate 12 in the figure, and the display element 1 is fixed to the back surface of the substrate 12 on the lower side in the figure, and by engaging the recess 7c formed in the holding member 7 with the end of the upper substrate 11 in the figure of the display element 1. 1 is integrally combined with 1. Note that if a sufficient distance cannot be maintained between the substrate 12 below the display element 1 and the circuit board 3, the circuit board 3 may be directly fixed to the back surface of the substrate 12 below the display element 1. In addition, the holding member 7
In the illustrated example, the circuit board 3 is integrally joined by dovetailing by press-fitting the end of the circuit board 3 formed in a size and shape that exactly engages into the dovetail groove 7d formed in the holding member 7. This is what I did. However, double-sided adhesive tape or adhesive may also be used.

[0011] Between the display element 1 and the circuit board, which are integrated with each other at a predetermined distance by the holding member as described above,
As shown in FIG. 2, a flexible wiring connection member 4 such as an FPC is bent and arranged in a substantially U-shape, and one end of the flexible wiring connection member 4 is connected to the upper electrode substrate 11 of the display element 1. The other end is connected to the electrode input terminal (not shown), and the other end is connected to the output terminal (not shown) of the circuit board 3.
(not shown) are conductively connected to each other. In addition, in the case of the figure, an integrated circuit 5 for driving a liquid crystal such as an LSI chip is arranged (mounted) on a flexible wiring connection member 4, and the integrated circuit 5 is mounted on the stepped portion of the substrates 11 and 12 of the display element 1. It is contained in S.

As described above, in the present invention, the display element 1 and the circuit board 3 are integrated by the holding member 7, which is advantageous in terms of vibration and shock resistance.
3 is inadvertently shifted and there is no fear that the connection point will peel or break, and reliability can be improved. Furthermore, if the substrates 11 and 12 of the display element 1 are made of a material with a small coefficient of thermal expansion, such as glass, which is commonly used, reliability against temperature changes can also be improved. Furthermore, by bending and arranging the flexible wiring connecting member 4 between the display element 1 and the circuit board 3, the connecting portion by the flexible wiring connecting member 4, and by extension the entire device, can be made small and compact. becomes possible. Furthermore, if the integrated circuit 5 is housed in the stepped portion S of the substrates 11 and 12 of the display element 1 as shown in the illustrated example, it is possible to absorb the thickness of the integrated circuit 5 and make the device thinner. becomes.

Further, the flexible wiring connection member 4 is disposed between the display element 1 and the circuit board 3, which are held at a predetermined distance by the holding member 7, and inside the frame 2, so that the terminal portions etc. are not exposed to the outside. Since it is not exposed, the flexible wiring connection member 4 or the integrated circuit 5 is less likely to be damaged or destroyed due to static electricity, foreign matter, etc., and the reliability of the electric circuit can be improved.

[0014] Also, the circuit board 3 and the flexible wiring connection member 4
By disposing it on the outer circumferential side of the display area R of the display element 1, it is possible to avoid overlapping with the circuit board 3 and the flexible wiring connection member 4 in the case of a device equipped with a backlight 6 as shown in the illustrated example. Since the backlight 6 can be arranged in the same direction, the thickness of the liquid crystal display device can be made as thin as possible, and the backlight 6 can be easily attached and detached during maintenance such as inspection or replacement. Note that the present invention can also be used with the backlight 6 removed, and can be applied to, for example, a reflective type liquid crystal display device that does not use a backlight, a liquid crystal display device for projection by an OHP projector, and the like.

Furthermore, since the display element 1 and the circuit board 3 are integrated by the holding member 7, handling during, for example, an assembly process is facilitated. For example, when assembling the display element 1 and the circuit board 3 into the frame 2, the display element 1 and the circuit board 3 can be assembled together with the holding member 7. in this case,
For example, as shown in FIG. 3, the frame 2 is provided with locking holes 2a and cut-out claws 2b for positioning during assembly, and correspondingly, the holding member 7 is provided with engagement protrusions 7a and cut-out recesses 7b. By providing this, the display element 1 and the circuit board 3 can be easily positioned and held at predetermined positions with respect to the frame 2. Further, if the upper end corner of the engaging projection 7a is formed into a slope as shown in the figure, the locking hole 2a can be easily engaged with the engaging projection 7a and the cutout recess 7b of the raised claw 2b. In this case, since the positioning of the cutout recess 7b with respect to the cut-and-raise claw 2a is performed at the lower part of the recess 7b, the positioning accuracy is not deteriorated due to the above-mentioned slope. In the figure,
Reference numeral 9 denotes a fixing member such as an adhesive for fixing the display element 1 to the frame 2, and is provided as necessary.

Furthermore, during assembly or maintenance such as repair, the display element 1 and circuit board 3 are removed from the holding member 7,
This can be done with the flexible wiring connection member 4 extended. When the flexible wiring connection member 4 is extended, all the terminals can be exposed, and the display element 1 and the circuit board 3 are separated by a distance, so the ease of assembly and repair is not impaired at all. Not yet.

Although the illustrated example uses a flexible wiring connection member 4 on which an integrated circuit 5 for driving a liquid crystal such as an LSI chip is mounted, a flexible wiring connection member 4 such as a heat seal on which an integrated circuit 5 is not mounted is used. The integrated circuit 5 may be placed on the circuit board 3 or the display element 1 using a member, and in that case as well, the integrated circuit is preferably housed in the stepped portion S of the electrode substrates 11 and 12 in the same manner as described above.

4 and 5 show other embodiments of the electro-optical device according to the present invention. FIG. 4 is a longitudinal cross-sectional side view of a part of a liquid crystal display device as an electro-optical device, and FIG. FIG. 3 is a longitudinal side view showing the configuration of a holding member with a circuit board.

In this example, the display element 1 and the circuit board 3 are positioned and held at a predetermined interval by the holding member 7, and they are sandwiched in the frame 2 having a substantially U-shaped cross section, as in the previous example. The other configurations are substantially the same as in the previous embodiment. That is, in this example as well, the holding member 7 is fixed to the display element 1 by the fixing means 8 such as adhesive, and the substrate 1 on the upper side of the display element 1 is inserted into the recess 7c of the holding member 7.
1 end is engaged. Further, the circuit board 3 is held by a holding member 7
The dovetail groove 7d is dovetailed. In the illustrated example, positioning with respect to the frame body 2 is achieved by providing a step 2c or the like on at least the inner surface of the frame body 2, and pushing the holding member 7 into the upper corner until it comes into contact with the step 2c. The end opposite to the display element 1 may be formed into a U-shape that is approximately the same shape as the inner surface of the frame, and the inner surface of the frame may be brought into contact with the circumferential surface of the U-shape for positioning.

With the above configuration, the back surface of the circuit board 3 is covered by the frame 2 and is not exposed to the outside, so that damage due to static electricity, foreign matter, etc., or short circuit of the circuit can be prevented. In addition, the frame 2 can be installed relatively early in the device assembly process and can be used as a means of protecting the flexible wiring connection member 4, etc., making it easier to handle during assembly and reducing costs. Realized. Furthermore, in the previous embodiment, the display element 1 was fixed to the frame body 2 with a fixing member 9 such as an adhesive, but in this embodiment, if the structure is such that the display element 1 is held by the spring force of the frame body 2, the above-mentioned fixation is possible. No parts are needed. Furthermore, the frame 2 may be made of extrusion molded synthetic resin such as ABS resin, or a metal plate such as a cold-rolled steel plate or stainless steel plate with an insulated surface, or any other appropriate material; however, if synthetic resin is used, the weight can be reduced. At the same time, insulation can be easily ensured. The same applies to the previous embodiment.

Although each of the above embodiments has been explained using a liquid crystal display device as an example, it can also be applied to a head portion of a contact type image sensor, or to various other electro-optical devices such as an EL display or a plasma display.

[0022]

As explained above, the present invention provides an electro-optical device in which a display element 1 such as a liquid crystal panel and a circuit board 3 for driving and controlling the display element 1 are electrically connected via a flexible wiring connection member 4. The circuit board 3 is integrally connected and held by a holding member to the edge of the display element 1 outside the display area, and a flexible wiring connection member 4 is provided between the circuit board 3 and the display element 1. Since the electro-optical device is bent and arranged, the entire device can be made smaller and more compact than the conventional electro-optical device, and the device can be easily assembled. Further, the flexible wiring connection member 4 is disposed between the display element 1 and the circuit board 3, and is protected by them, thereby improving durability and reliability. Furthermore, in the case where the backlight 6 is provided on the back side of the display element 1, since the flexible wiring connection member 4, the circuit board 3, etc. do not get in the way, it can be easily placed in a predetermined position, and circuit board 3
A backlight with a desired thickness can be used regardless of the thickness of the backlight. Furthermore, since the circuit board and the like do not get in the way during maintenance of the backlight, it is easy to remove and replace the backlight.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is an enlarged longitudinal sectional front view taken along line A-A in FIG. 1;

FIG. 3 is a longitudinal side view showing the configuration of a holding member for a display element and a circuit board.

FIG. 4 is a vertical sectional side view showing another embodiment of the liquid crystal display device according to the present invention.

FIG. 5 is a vertical cross-sectional side view showing the configuration of a holding member for a display element and a circuit board.

FIG. 6 is a vertical cross-sectional view of a conventional liquid crystal display device.

FIG. 7 is a longitudinal sectional view of another conventional example.

[Explanation of symbols]

1 Display element 2 Frame body 3 Circuit board 4 Flexible wiring connection member 5 Integrated circuit 6 Backlight 7 Holding member

Claims (2)

[Claims] 1. In an electro-optical device in which a display element such as a liquid crystal panel and a circuit board for driving and controlling the display element are electrically connected via a flexible wiring connection member, an edge of the display element outside the display area of the display element is provided. 1. An electro-optical device, characterized in that a circuit board is integrally connected and held by a holding member, and a flexible wiring connection member is bent and arranged between the circuit board and a display element. 2. An LS is provided on the flexible wiring connection member.
Claim 1, wherein an integrated circuit such as an I-chip is mounted, and the integrated circuit is located within a stepped portion of a pair of substrates of a display element.
The electro-optical device described.