JPH02310532A - Film liquid crystal - Google Patents

Abstract

PURPOSE:To easily and efficiently form leader electrodes which can be soldered and to simplify the mounting and connecting of a film liquid crystal by forming a metallic layer over the entire part of the leader part of transparent electrodes and cutting away the leader parts to a recessed shape down to the position deeper than the width of the metallic layer exclusive of the parts thereof corresponding to the transparent electrodes. CONSTITUTION:The film liquid crystal is constituted by using films for substrates 1, 1' and the leader parts are formed by extending the transparent electrodes 2' consisting of an indium oxide system. Electrolytic copper foil 14 having a dendrite-like rugged surface with a conductive tacky adhesive agent of a prescribed width is press welded onto these parts. The parts where there are no transparent electrodes 2' are then cut away. The value at which shorting does not arise at the time of the later soldering may be selected for the width to be cut away. There is no limitation on the installation method occurring in the dimensional accuracy of the electrodes in this way and the solderable leader electrodes are formed by the simple operation. The easy mounting and connecting of the film liquid crystal are executed in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a film liquid crystal which is intended to further reduce the weight and thickness of liquid crystal display elements.

Conventional technology LCD display A-type uses an indium oxide-based transparent thin film for polarization, which makes it difficult to solder when connecting to a circuit. ), and in cases where the electrode spacing is small or thinning is required, methods such as thermocompression bonding of an anisotropic conductive adhesive sheet are used. If you dare to solder, there are methods such as printing or plating a solderable silver paste only on the transparent thin film electrode, but there are many problems due to limitations in manufacturing and usage of liquid crystal cells. Practical use is limited.

Problems to be Solved by the Invention When commercializing a film liquid crystal that has been made thinner by using a film substrate instead of a conventional glass substrate, the effect of thinning is halved by the contact of the electrode lead-out portions,
Furthermore, when mounting the anisotropic conductive sheet on a set's printed circuit board, etc., the equipment for uniformly thermocompressing the anisotropic conductive sheet is complex and requires space, making it inefficient and inflexible, especially when reading directly onto small products. It wasn't effective.

Therefore, the present invention aims to simplify the installation and connection of the film liquid crystal by easily and efficiently forming one lead-out pole that can be soldered using a method that is made possible because the substrate of the liquid crystal cell is not glass but a film. That is.

In general, a liquid crystal display device is manufactured by forming transparent electrodes 2.2' in a desired pattern on a transparent substrate 1.1' such as glass or film, as shown in Figure 31, and placing the transparent electrodes 2.2' in a desired pattern relative to each other at a constant interval. Then, the peripheral portion is further coated with sealant 3, and the inside is filled with liquid crystal 4. Polarizing plates 6, 6', reflecting plates, etc. are attached to both sides as necessary. In order to connect this to the drive circuit, a transparent electrode 2' for extraction is formed in a stripe shape on the extension part of one substrate 1' as shown in Fig. 3, and on this part as shown in Fig. 4. It is used by being crimped to a terminal portion 12 such as a copper foil of a flexible substrate or a general printed circuit board 11 via a zebra rubber or anisotropic conductive adhesive sheet 13 having conductivity only in the vertical direction. However, these anisotropic conductive rubbers and adhesives are required to have sufficient conductivity in the vertical direction without leaking in the horizontal direction, so it is difficult to satisfy these conditions and still obtain sufficient adhesive strength. This means that there are many restrictions in terms of materials, structure, etc., and it is difficult to obtain a product that is satisfactory in terms of reliability, so in practice, auxiliary measures such as reinforcement are used. In the case of film substrates, there are many problems due to bending.

As a means to solve the problem, the present invention, instead of using an anisotropic conductive material with many such restrictions, forms a metal layer over the entire lead group of the transparent electrode,
The portion of the drawn-out portion other than the portion corresponding to the transparent polarization is cut out in a concave shape to a position deeper than the width of the metal layer. In this case, the metal material may be a conductive paint, a plating layer, a thin film layer formed by vapor deposition or sputtering, or a metal foil coated with a conductive adhesive. You can choose as appropriate.

Since it is sufficient to form the conductor layer/section of the metal layer over the entire length regardless of the interval I between the working extraction electrodes, the operation is simple and sufficient conductivity can be obtained. Further, since special functions such as anisotropic conductivity are not required, sufficient conductivity and adhesive strength can be satisfied at the same time. Furthermore, since it is not necessary to form a metal layer only on the lead-out portion, there is no need for complicated measures or operations regarding dimensional accuracy, inter-terminal seats, etc., and it is only necessary to select the precision and method of cutting. Furthermore, since a semi-fixable conductor layer can be easily formed, there is an advantage that the liquid crystal element can be easily and instantaneously connected using a conventional soldering method, without having to thermocompress the liquid crystal element using a complicated device.

As described above, the present invention provides a terminal connection method unique to film liquid crystals, which is not possible with liquid crystals using glass substrates.

Example (Example 1) A liquid crystal cell having the structure shown in Fig. 3 was prepared using a 200 μm thick PXS (polyether sulfone) film with an integrated polarizing plate as the substrate 1.1'. Configure. At this time, the lead-out portions are formed by extending indium oxide-based transparent electrodes, and are formed at intervals of IMMg and 13r1. On top of this, as shown in Figure 1, an electrolytic copper foil (36 μm) 1 with dendritic unevenness with a conductive adhesive of width 1.6 mm is applied.
Crimp 4. Next, as shown in Figure 2, the transparent electrode 2' is
The width of the portion to be cut out may be the same as or less than the width of the transparent electrode 2', as long as the width is selected so as not to cause short circuit during soldering later. However, the cut length is 140 mm width of the formed electrolytic steel foil (
1, s m ) or more so that adjacent terminals are completely separated. Since the film is 200 .mu.m thick and the copper foil is about 36 .mu.m thick, this cutting can be done by t1 press punching. The film liquid crystal element thus obtained can be easily connected to the copper foil portion of a flexible printed circuit board using a soldering iron, and is particularly effective for attachment to small equipment.

Also, if you bend the end face and form it all the way to the back side, it will become even stronger.

(Example 2) A similar effect was obtained when a solderable low-temperature curing silver paste was printed as a conductor using a metal layer on a film liquid crystal element formed in the same manner as in Example 1.

(Example 3) Similar effects were obtained when a nickel plating layer was formed as a conductor to a thickness of 2 to 3 μm in the same manner as in Example 1.

Effect of the invention The present invention features free cutting, which is a feature of film substrates.

Utilizing the feature of being able to perform cutting such as punching, the drive is 1t! The lead electrode is formed so that connection α with one circuit can be easily made by soldering. This method involves forming a metal layer over the entire extraction electrode part, and cutting off the entire film substrate except for the electrode part.This method provides sufficient conductivity and adhesive strength, and also allows for reliable connection by soldering. This provides higher reliability than connections using anisotropic conductive materials. Further, since a metal layer is formed on the entire surface, there is no IJJ error in the construction method due to the dimensional accuracy of the electrode, and a lead electrode that can be soldered can be formed with a simple operation. the result,
Connection with the drive circuit does not require complicated equipment for thermocompression bonding, and conventional simple soldering methods can be applied, making it particularly effective in forming display parts of small devices, and has practical effects. is remarkable.

[Brief explanation of drawings]

1 and 2 are plan views showing part of the manufacturing process of a film liquid crystal according to an embodiment of the present invention, FIGS. 3a and 3b are a cross-sectional view and a top view of a general liquid crystal display element, and FIG. 4 FIG. 2 is a cross-sectional view showing an example of connection with a drive circuit. 1.1'...Substrate, 2,2'...Transparent electrode, 4...Liquid crystal, 14.Old...Electrolytic copper foil.

Claims (5)

[Claims] (1) A film liquid crystal characterized in that a metal layer is provided on the lead-out portion of the transparent electrode of a liquid crystal cell formed by sandwiching the liquid crystal between film substrates, and the portion of the lead-out portion other than the transparent electrode is removed. (2) The film liquid crystal according to claim 1, wherein a metal thin film layer is provided on the lead-out portion of the transparent electrode. (3) The film liquid crystal according to claim 1, wherein a metal foil is provided on the lead-out portion of the transparent electrode via a conductive adhesive layer. (4) The film liquid crystal according to claim 1, wherein a thin metal plate is crimped along the substrate at the lead-out portion of the transparent electrode. (5) The film liquid crystal according to claim 3, wherein an electrolytic copper foil is pressure-bonded to the lead-out portion of the transparent electrode so that the dendrite surface is in contact with the lead-out portion of the transparent electrode.