JPS5915278A - Multi-layer type liquid crystal display element - 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 [Technical field to which the invention pertains] The present invention relates to the structure of inter-substrate wiring within a multilayer liquid crystal display element, which is constructed by laminating liquid crystal display elements in multiple layers.

[Prior Art and its Problems] Several types of structures have been proposed for conventional multilayer liquid crystal display elements (hereinafter referred to as SU, LCI) depending on the method of installing external signal input terminals. In the following, a two-layer LCD using an intra-element wiring method will be explained as an example. Here, the intra-element wiring method refers to a method in which external signal input terminals are provided on one electrode substrate, and inter-substrate wiring is provided inside the display element as a branch circuit for input signals to each electrode substrate.

FIG. 1(a) is a plan view, FIG. 1(b) is a cross-sectional view, and FIG. 1(C) is an enlarged view of an inter-board wiring section, and further explanation will be added.

Transparent electrodes 14 on glass substrates 11, 12, 13,
In a two-layer LCD in which a liquid crystal is held between the substrates, the input terminal portions 14 and 1.5 are provided at the ends of opposing surfaces of the substrates 11 and 12 that face each other across the intermediate substrate J2. Both input terminals 14 and 15 are provided with an inter-board wiring 16 made of a conductive member, and are electrically connected.

This inter-substrate wiring 16 performs internal wiring within the device, so even when only the transparent electrode 14 on the electrode substrate 11 is used as an input terminal, voltage is also applied to the second liquid crystal layer between the substrates 12 and 13. It becomes possible to do so. However, 1゜In this case,
Similar to the normal one-layer type LCI), the so-called 2. .

The substrate 11 is transferred via a conductive member called a transfer.
It is necessary that a voltage be applied from part of the electrodes on the substrate 2 and 13 to the electrode 17 on the substrate 2.

A method of providing such inter-board wiring 16 is to assemble the 2M cells and then apply conductive paint, conductive adhesive, etc. to the electrode terminals 14 and 15 facing each other between the boards 11 and 13 using a dispenser or syringe. A common method is to discharge the liquid between the two. However, as shown in FIG. 1(C), the distance between the opposing electrode terminals +4 and ]5 is the thickness of the intermediate substrate 12, which is the same as the glass substrate commonly used for L CTJ. The thickness is 085-11. It is necessary to obtain a reliable electrical connection through such a narrow gap, and with conventional dispensing coating methods, it is difficult to set conditions such as the viscosity of the conductive material and the sootropic property, and the dispensing method itself However, they also have deficiencies such as difficulty in mass production. Furthermore, the discharge coating method has the drawback that if the coating pitch, that is, the pitch of the electrode terminals is set to approximately the same level or less as the substrate gap, it will come into contact with the adjacent conductive material, making it impossible to achieve high density. .

In addition, other methods of applying conductive substances, such as screen printing a conductive paste, are also considered, but two-layer T,
It is extremely difficult to form a thick film (0.5 to 1.1 mm), such as the wiring between CD substrates, with a small coating area.
Not a practical method.

Furthermore, in the discharge coating method and the ultra-thick film screen printing method, since a large amount of conductive material is applied, a short circuit phenomenon between terminals may occur due to capillary phenomenon.

This short circuit phenomenon occurs between the intermediate board 12 and both side boards 11 and 13.
A small gap 19 with the same spacing as the liquid crystal layer is generated on the outer circumference of the part 18 between 7 and 18, and conductive fine particles contained in the low-viscosity binder are passed horizontally through this small gap J9 by capillary action. This is a phenomenon in which the electrode terminal spreads in the opposite direction and short-circuits with adjacent electrode terminals. There is also a drawback that the manufacturing yield of the two-layer LCD decreases due to this short-circuit phenomenon.

OBJECT OF THE INVENTION] The present invention improves the drawbacks of the conventional discharge coating method, etc. described above, and provides a multilayer LCD that facilitates the manufacturing process of wiring between substrates within an element and improves the reliability of connections. I am with the purpose of doing something.

[Summary of the Invention] In order to achieve the above-mentioned object, the present invention uses a pressurized conductive rubber that can be changed into high conductivity and insulation properties depending on the presence or absence of pressurizing force as a wiring member between substrates within an element. It is something.

Pressurized conductive rubber uses highly insulating rubber as a base material and contains conductive particles (metal, carbon, metal coated on the surface of the particles).
- 100%, etc.) are dispersed to an appropriate concentration, for example, 0.3 to 1 with a pressure of fi/cr/l lit
It has a low resistance value of 0 Ω/d, and has a resistance of 10 M when no pressure is applied.
There is one (Japan Synthetic Rubber Co., Ltd.) that has high insulation properties of Ω/7 or more.

If such a pressurized conductive rubber is held between the substrates and only the portions between predetermined electrode terminals are pressurized by some method, good inter-substrate wiring can be obtained.

As a method of selectively pressurizing the terminal portion, it can be easily obtained by providing a convex portion made of a conductive substance on the substrate or pressurized conductive rubber by selectively applying a conductive paint or the like.

[Effects of the Invention] As described above, the conductive protrusion provided in advance on the board terminal portion or the pressurized conductive rubber and the pressurized conductive rubber prepared in advance are inserted between the substrates or installed at the time of cell assembly. It is relatively easy to mass-produce, easy to handle, and also provides reliable inter-board wiring with reliable kit electrical connection.

[Embodiment of the Invention] FIG. 2(a) is a cross-sectional view, and FIG. 2(b) is a plan view of an embodiment in which the inter-substrate wiring within an element using the pressurized conductive rubber of the present invention is applied to a two-layer type T and CD. Illustrated in the diagram.

In FIG. 2(a), transparent electrodes 24a, 24 are provided on one side.
1.1 m thick glass substrates 21 and 23 on which transparent electrodes Z7a and 2'7b are formed, and 0.71 m thick 11r glass substrate 4 on which transparent electrodes Z7a and 2'7b are formed on both sides, using a sealing material. Glue and attach the substrate.

A two-layer guest-host type LCD was created by injecting liquid crystal between the layers and providing a transfer layer. A conductive paint is applied in advance to a thickness of approximately 0.14 mm on a portion of the electrode terminal portions facing the substrate 21' by screen printing, respectively, to form conductive convex portions 28a, 28b, and 28c.

28d, and after the cell is assembled, the conductive protrusions are located at substantially opposite positions. Between these opposing conductive convex portions, rod-shaped pressurized conductive rubber 26a, 2
By press-fitting 6b, the conductive convex part 1, the sandwiched part is about 0.1 m from Q, 5 rays to 0.5111.
It was compressed to 1m and showed a low resistance value of about 100Ω. Therefore, the opposing electrodes 24a and '25a, 24
b and 25b could be connected with a sufficiently low resistance value for LCD wiring.

Although FIG. 2(b) shows a plan view, in order to simplify the drawing, the pressurized conductive rubber 26a of the upper terminal portion is in a state before being press-fitted.

[Other Examples of the Invention] In addition to the screen printing method, a discharge method was effective as a method for forming the conductive convex portions. Further, even if the conductive convex portion is formed only on one surface of the opposing terminal portion, it can sufficiently perform its selective pressing function. However, in this case,
The thickness of the convex part was required to be about twice that of the case where it was formed on both substrate surfaces0 It was also equally effective to form the conductive convex part on the pressurized conductive rubber surface. . In this case, a conductive material having some elasticity is preferable, and a rubber-based conductive paint is suitable.

Furthermore, as a type of pressurized conductive rubber, conductive particles made of spherical silicone rubber with a diameter approximately equal to the substrate spacing, with a metal film coated on the surface, are dispersed within an insulating sheet, and conductivity is anisotropic. A similar effect could be obtained by using a pressurized conductive rubber sheet that had been given properties. Furthermore, even when applying a pressurized conductive rubber with conductive anisotropy, by forming the aforementioned conductive convex portions, the entire rubber sheet can be partially pressurized, making it possible to keep the pressurizing force low. This was very effective because it made it possible to reduce the stress applied to the seal part. This stress reduction effect made it possible to improve the reliability of the seal.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of a conventional two-layer LCD and wiring between substrates within the element, and FIG. 2 is a diagram showing an embodiment of the present invention. 11.12, 13, 21, 22.23...Substrate, 1
4, 15, 17.24a, 24b, Z5a, 7-'5
b, 27a; Z7b,..., transparent electrode, 16... conductive paint for inter-board wiring. 26a, 26b... Pressurized conductive rubber, 28a, 28b, 2Ftc, 28d... Conductive convex portion. Agent: Patent attorney Kensuke Chika (and 1 other person)

Claims (3)

[Claims] (1) At least three electrode substrates are arranged facing each other, a liquid crystal is held between the electrode substrates, an external signal input terminal is provided above at least one electrode substrate, and a drive signal from the input terminal is transmitted to each opposing electrode. In a multilayer liquid crystal display element in which an inter-substrate wiring is provided within the element to apply an electric current to, the part pressurized with a predetermined pressure exhibits high conductivity as an intra-element inter-substrate wiring member. A multilayer liquid crystal display element whose parts are made of pressurized conductive rubber that exhibits insulation properties. (2) A multilayer liquid crystal display according to claim 1, characterized in that a conductive convex portion having a predetermined thickness is provided on the electrode terminal portion of the electrode substrate of the intra-device inter-substrate wiring portion. element. (3) Pressurized conductive rubber - wiring part between boards inside the element! 2. The multilayer liquid crystal display element according to claim 1, further comprising a conductive protrusion having a predetermined thickness in a portion corresponding to the pole terminal.