JPH0134364B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a laminated liquid crystal display device using a plastic substrate.

A laminated display element in which two or more liquid crystal layers are formed can produce complex displays. It has advantages such as multi-color or high-contrast display and easy-to-read display, and its use has been increasing in recent years.

A typical example of this multilayer liquid crystal display element is a two-layer type, and two layers with four substrates and two layers with three substrates are known.

FIG. 1 is a cross-sectional explanatory diagram of an example of two layers of four substrates.

Please note that all figures, including those below, are exaggerated in the thickness direction for clarity.
The actual thickness of the electrodes and liquid crystal layer is extremely thin compared to the thickness of the substrate.

This type of two-layer liquid crystal display element is basically formed by bonding two liquid crystal display elements, and the substrates 2A and 2B having electrodes 1A and 1B are sealed with sealants 3A and 3B. A liquid crystal display element formed by sealing substrates 2C and 2D with electrodes 1C and 1D with sealants 3C and 3D are bonded together with an adhesive 4, and the two liquid crystal display elements are simply connected. It's just a combination.

In this example, the electrode extraction portions are normally provided at the upper end 5B of the substrate 2B and the lower end 5C of the substrate 2C, and two connectors are required for connection to an external circuit. In order to do this with one connector and form an electrode extraction part on only one side, a transfer that cross-connects the board in the thickness direction is required, and it is difficult to obtain a reliable transfer. The problem was that it was difficult or required adding many steps.

Further, FIG. 2 shows an example of three substrates, with the center substrate being slightly larger.

In this example, the upper substrate 12A and the lower substrate 12C have electrodes 11A and 11D on their inner surfaces, and only the central substrate 12B has electrodes 11B and 11D on both sides.
It has C. Each board is covered with sealing material 13A,
It is sealed with 13B, 13C, and 13D.

In this structure, the electrode lead-out portions are usually provided on both sides 15B and 15C at the end of the central board, and two connectors are also required.

These conventional laminated liquid crystal display elements all require two electrode extraction parts, and in order to combine them on one surface, it is necessary to make a hole in the substrate or to transfer around the outer wall of the substrate, and the manufacturing process This method has disadvantages such as increased complexity and reduced reliability.

The present invention prevents such drawbacks and concentrates the electrode extraction portions on one surface of one substrate, and in a laminated liquid crystal display element using at least one plastic substrate, the electrodes are arranged on one common plastic substrate. This is a laminated liquid crystal display element that has two or more liquid crystal cells, which are bent and joined to form a laminated structure.

Since the liquid crystal display element of the present invention uses one common substrate as a plastic substrate and is bent, all the electrode extraction parts can be concentrated on one surface, and a transfer that penetrates the substrate can be formed. There's no need to.

Furthermore, since a large number of laminated liquid crystal display elements can be manufactured at the same time, they can be manufactured with high productivity similar to the manufacturing of conventional single-layer liquid crystal display elements.

Next, the laminated liquid crystal display device of the present invention will be explained in detail based on the drawings.

FIG. 3 is an explanatory cross-sectional view of the two-layer liquid crystal display element before bending, and FIG. 4 is an explanatory cross-sectional view after bending.

Electrodes 21A and 21D are provided at corresponding portions on one common substrate 22A. This substrate is a plastic substrate having sufficient flexibility, which is bendable and does not cause the electrode leads to break when bent. Specific examples of the material include polyester, cellulose acetate, acrylic, etc., and the material may be appropriately selected from those that are bendable and have sufficient strength. For this electrode, materials that form transparent electrodes, including ordinary ITO, can be used.If necessary, a reinforcing layer such as a metal lead or metal overcoat may be formed on the bent portion. An insulating overcoat or the like may be provided thereon to prevent deterioration of the leads due to moisture or the like. Particularly when the radius of curvature becomes small, care must be taken not to cause wire breakage, and if necessary, grooves may be provided on the opposite surface of the plastic substrate.

On this substrate, substrates 22B and 22C with other electrodes 21B and 21C are arranged, and sealing materials 23A and 22C are arranged.
Sealed with 23B, 23C, and 23D.

These two substrates 22B and 22C may be made of plastic or glass, and their thicknesses may be appropriately selected.

The product manufactured in this way is bent from approximately the center and adhesive 24 is applied to the outer surface of the substrates 22B and 22C.
The two layers are bonded together to form a two-layer liquid crystal display element as shown in FIG.

On the contrary, it can be bent in the opposite direction, and a common plastic substrate can be joined at its outer surface to form a two-layer liquid crystal display element.

FIG. 5 shows a plan view of an example in which a plurality of two-layer liquid crystal display elements are manufactured at the same time, in which substrates 32B and 32C are connected to each other at two locations on a common substrate 32A. This is 36A, 36B, 3
It is cut at the arrow 6C to form each element. This cutting may be performed before or after bending and joining.

FIG. 6 shows an example of a three-layer structure including a common plastic substrate 43A and substrates 43B, 43C, and 43D. In this three-layer liquid crystal display element, the electrode extraction portion is on one surface of the substrate 43A.
It can only be taken out from 5A.

Note that the transfer between the common plastic substrate and other substrates may be the transfer used in normal single-layer liquid crystal display elements, and may be in-plane, within the seal, or outside the seal. good.

It should be noted that these substrates are transparent substrates except for at least the rearmost substrate, and each has a desired electrode as necessary.

These substrates may have an undercoat layer of SiO ₂ , Al ₂ O _3, etc., and an overcoat layer for various orientations, if necessary, and may also have multilayer electrodes. It may have an alignment layer, a printing layer, etc. for fixed display.

Further, a color filter, a color polarizing plate, a polarizing plate, a 1/4 wavelength plate, etc. may be laminated, and when used as a reflective type, a reflective electrode, a reflective plate, a semi-transparent reflective plate, etc. are provided.

Various known liquid crystals can be used for this multi-layer liquid crystal layer, and any liquid crystal material that changes its optical properties upon application of an equal voltage may be used. , the same or different liquid crystals are used in each layer. Note that this liquid crystal injection may be performed in the state shown in FIG. 3 or may be performed in the state shown in FIG.

A specific example of the liquid crystal injected into this multilayer liquid crystal layer is, for example, one in which TN liquid crystal is injected into the first layer with solid electrodes on the entire surface and the second layer with the desired display pattern, thereby enabling black and white inverted display. , 2 of the same pattern
Two-color display by forming a layer and injecting guest-host liquid crystal containing the same pleochroic dye to improve contrast, and injecting two types of guest-host liquid crystal containing two types of pleochroic dye, respectively. There are things that make it possible.

The electrodes provided on these plurality of liquid crystal layers can be a whole surface, a Japanese character segment, a dot matrix, various shapes, etc., and may be selected and used as necessary. In particular, in the present invention, the electrode leads of the plurality of layers are common. The effect is enhanced by wiring.

For example, in order to drive an 8-digit Japanese character segment, 3+3×8=27 electrode terminals were required for 1/3D, and twice that number, 54, were required for two layers.
In the case of this Japanese segment type, increasing the duty ratio will significantly complicate the wiring, so it is usually 1/3D.
Used below.

On the other hand, in the present invention, the size can be easily reduced to 1/6D, and as a result, all the wiring can be completed with 6+3×8=30 electrode terminals.

If this is a 20 character dot matrix, 1/8
In D, 8 + 5 × 20 = 216 lines, which is twice the number of 108 lines, and 1/ of the present invention.
With 16D, there is a big difference: 16 + 5 x 20 = 116 lines.

Furthermore, in the case of a two-layer guest-host liquid crystal display element with the same pattern and the same liquid crystal for the purpose of improving contrast, by adopting the structure of the present invention, the number of terminals can be exactly the same as in the case of a single layer. becomes.

In the present invention, for example, at least one of the substrates can be a glass substrate to improve the strength, all of the substrates can be made of plastic to give flexibility, and the rearmost substrate can be a reflective substrate or a flat substrate. It can also be used as a light emitting body, a light guide plate, etc., and furthermore, it is possible to use the plastic substrate as a polarizing plastic substrate.

Further, sealing materials, barriers, transfers, spacers, etc. are also selected as appropriate or provided as necessary.

Further, as an adhesive for joining a plurality of liquid crystal cells, a common resin adhesive, a pressure-sensitive adhesive, etc. can be used, or they may be joined so that they do not move by mechanical means.

As described above, the present invention allows the electrode extraction portion to be integrated into one, making it easy to connect with external circuits and improving productivity, and can be applied to various patterns in the future. .

[Brief explanation of drawings]

1 and 2 are explanatory diagrams of a conventional two-layer liquid crystal display element, and FIGS. 3 to 6 are explanatory diagrams of a laminated liquid crystal display element of the present invention. 21A, 21B, 21C, 21D: electrodes; 22
A: plastic substrate, 22B, 22C: substrate,
23A, 23B, 23C, 23D: Seal material.

Claims (1)

[Claims] 1. In a laminated liquid crystal display element using at least one plastic substrate, two or more liquid crystal cells are constructed on one common plastic substrate, and the cells are bent and joined to form a laminated structure. A multilayer liquid crystal display element. 2. One end of the common plastic substrate is not provided with a liquid crystal cell and is used as a lead extraction portion, and the leads of all liquid crystal cells are taken out from the lead extraction portion.
The laminated liquid crystal display element described in 2.