JPS61167976A - Liquid crystal display unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid crystal display device that has a wide effective display area and is suitable for a multi-panel structure.

(Prior Art) FIG. 3 is a cross-sectional view of a conventionally commonly used liquid crystal display device, in which 1 is a substrate made of a glass plate forming a liquid crystal cell;
2 is a transparent electrode formed on the glass surface, 3 is a liquid crystal agent, and 4 is a sealing part.

The transparent electrode 2 is connected to a circuit board 6 by an elastic connector 5. Although this structure makes it easy to replace the liquid crystal panel, since it is simply a press-contact, the reliability is low and a press-contact mechanism is required. FIG. 4 shows another example in which a transparent electrode 2 and a circuit board 6 are connected using a film connector 7 made by printing conductive paste on a flexible film.

This case is superior to the connection using the elastic connector 5 in that the positional relationship between the liquid crystal panel and the circuit board can be freely adjusted.

(Problem to be solved by the invention) As another structure, there is one in which a flexible wiring board is thermocompressed using an anisotropic conductive adhesive, which is a method similar to the second example, but this is common to all structures. The problem is that an eave-like part with a width of several millimeters on which external connection electrodes are formed is required on the outer periphery of a liquid crystal cell forming a liquid crystal display panel. the result.

The area of the bottom causes the size of the liquid crystal cell to be too large compared to the actual display area, and especially in the case of a multi-panel system in which multiple liquid crystal display elements are arranged side by side to form a large screen, the space between each display element A problem arises in that there is a non-display area corresponding to the area of the eaves, making it extremely difficult to see.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the liquid crystal display device of the present invention has a flexible wiring on the outer peripheral end surface which is formed smoothly with a space left outside the sealing part of the liquid crystal cell. It has a structure in which the plates are glued together.

(Function) Since the liquid crystal display device configured in this manner does not require an eave-shaped part on which external connection electrodes are formed on the liquid crystal cell/lj, the liquid crystal cell size is reduced by the area of the eave part, and the effective display area is reduced. The size can be reduced to just the area of the seal and a small space outside it, making it possible to significantly reduce the size compared to the 5 to 6 mm wide eaves in general liquid crystal cells. . Further, the small space provided outside the seal portion of the liquid crystal cell is extremely effective for increasing the exposed area of the transparent electrode and obtaining reliable electrical connection.

(Example) An example of the present invention will be described based on FIGS. 1 and 2. FIG. 1 is a sectional view of a liquid crystal display device according to an embodiment of the present invention. The liquid crystal cell has a structure in which two substrates 1 made of glass plates provided with transparent electrodes 2 are attached with a minute cap filled with a liquid crystal agent and bonded together by a sealing part 4, and the outside of the sealing part 4 is approximately 0.2 The end face was cut off and lightly polished using a diamond grindstone. 8
is the base film of the flexible wiring board, which has a thickness of 25
It is a μ polyimide film, and the conductor portion 9 is patterned to match the electrodes of the liquid crystal cell.

Reference numeral 10 denotes a conductive adhesive, which is printed on the conductor portion 9 and is adhered to the end face of the liquid crystal cell. This conductive adhesive may be printed not on the conductor part 9 of the flexible wiring board but on the end face of the liquid crystal cell. When the flexible wiring board is bonded to the liquid crystal cell by applying pressure, the adhesive 10 as shown in the figure
flows slightly toward the seal part side from the end face and becomes completely transparent electrode 2.
A reliable connection can be obtained by making contact with the The space provided between the seal part and the end face of the liquid crystal cell has a remarkable effect on increasing the contact area between the transparent electrode and the conductive adhesive' and improving the reliability of the connection, but due to the accuracy of glass cutting and polishing, It is difficult to reduce the width of the space to 0.1 m or less, and if it exceeds 2 cm, the effect of reducing the external dimensions by removing the eaves will be weakened, so it is desirable to set the space width to a range of 0.1 to 2 cm.

FIG. 2 is a sectional view of another embodiment of the invention.

The liquid crystal cell is cut leaving 0.21 mm on the outside of the seal part 4,
Lightly sanded. Conductive ink 11 is screen-printed on the end face of this liquid crystal cell to form electrodes, and a base film 8 of a flexible wiring board is pressed through an anisotropic conductive adhesive 12 to obtain an electrical connection. 0 In this embodiment, the electrodes were formed by screen printing, but for example, a conductive paste may be printed on a release film and transferred onto the end face of the liquid crystal cell using a thermal transfer method. In such a configuration, the adhesive force of the flexible wiring board to the liquid crystal cell is generated by the anisotropic conductive adhesive;
The conductive ink that forms the electrodes can place more emphasis on printability than on adhesive strength, making it possible to print fine patterns and making it suitable for narrow-pitch electrodes.

(Effects of the Invention) According to the present invention, since the external connection electrodes in the liquid crystal cell are formed with an extremely narrow width, the effective display area is wide. In a panel-type display device, the seam between each panel is almost equal to the seal width of the liquid crystal cell, so the width can be kept to about 21 mm, which is rarely a problem in practice. Since a sufficient contact area with a connecting material such as a flexible wiring board can be obtained, an excellent effect can be obtained in that the reliability of the external lead is extremely high.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of another embodiment, FIG. 3 is a cross-sectional view of an example of a liquid crystal display device according to the prior art, and FIG. The figure is a sectional view of another example. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Transparent electrode, 3...Liquid crystal agent, 4...Seal part, 5...Elastake connector, 6...Circuit board, 7...Film connector, 8 ... base film of flexible wiring board, 9 ... conductor part of flexible wiring board, 10 ... conductive adhesive, 11 ... conductive ink,
12...Anisotropic conductive adhesive. Patent applicant: Matsushita Electric Industrial Co., Ltd., Figure 1, Section 2

Claims (3)

[Claims] (1) In a liquid crystal cell with a structure in which two substrates with transparent electrodes are placed facing each other with a small gap between them, and the periphery is sealed, the outer peripheral end face is formed smoothly with a space left outside the sealing part. A liquid crystal display device characterized in that a flexible wiring board is bonded to form an external lead. (2) An electrode made of conductive paste is formed on the outer peripheral end surface of the liquid crystal cell.
1) The liquid crystal display device described in item 1). (3) The liquid crystal display device according to claim (1) or (2), wherein a flexible wiring board is bonded via an anisotropic conductive adhesive.