JPH04198922A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To substantially prevent the influence of static electricity and noise and to prevent malfunctions by grounding the dummy terminals of an LCD via the dummy patterns of flexible substrates or the earth patterns of a printed wiring board. CONSTITUTION:The terminal parts 1a of the liquid crystal display element (LCD) 1 are provided with the dummy terminals 12 which respectively consist of ITO films, etc., like electrode terminal 5 groups but are independent from the electrode terminal 5 groups in the positions superposing on the flexible substrates 6 disposed adjacent to each other. The dummy patterns 13 independent from the lead pattern 8 groups are provided on both sides of the lead pattern 8 groups respectively on the flexible substrates 6 connected to the terminal parts 1a. The dummy patterns 13 on the flexible substrates 6 are so formed as to exist on the common dummy terminals 12. The dummy patterns 13 are grounded via the printed wiring board 10. The LCD 1 is substantially prevented from receiving the influence of the static electricity and noise in this way and is prevented from malfunctions.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a liquid crystal display device in which a group of electrode terminals of a liquid crystal display element (hereinafter abbreviated as LCD) is connected to a printed wiring board via a flexible substrate. particularly regarding its grounding structure.

[Prior Art] FIG. 2 is a plan view of essential parts of a conventional example of this type of liquid crystal display device.

In the same figure, the LCD generally indicated by reference numeral 1 includes an upper glass substrate 2, a lower glass substrate 3, a liquid crystal (not shown) sealed between both glass substrates 2.3, a polarizing plate 4, etc. Transparent electrodes (not shown) made of ITO or the like and corresponding to display patterns are formed on opposing surfaces of both glass substrates 2 and 3, respectively. Further, on the peripheral edge of the LCD 1, a terminal portion 1a is provided in which a large number of electrode terminals 5 for external connection are arranged side by side.

5 groups of electrode terminals are each formed to extend from the transparent electrode.

The flexible substrate generally indicated by reference numeral 6 includes a base film 7 made of polyimide film or the like, a large number of lead patterns 8 formed by etching copper foil on the base film 7, and a group of 8 lead patterns covered. The lead pattern 8 group is exposed at both ends of the base film 7.

Note that an electronic component 9 such as an LSI is mounted on the flexible board 6.

Then, a plurality of flexible substrates 6, . ... are placed in parallel, and the heater chip (
By pressurizing and heating each flexible substrate 6 using a
Corresponding electrode terminals 5 and lead patterns 8 are connected and fixed.

In addition, the printed wiring board generally indicated by the reference numeral 10 includes L
A circuit pattern and various electronic components for driving the CDI are arranged, and 11 groups of connection terminals of this circuit pattern are made of an anisotropic conductive sheet (not shown) similar to the above connection structure.
It is connected and fixed to the group of lead patterns 8 on the flexible substrate 6 via.

Note that the printed wiring board 10 is caulked and fixed in a casing (not shown), so that the display area of LC:I)1 is exposed in the display window of the casing.

[Problems to be Solved by the Invention] Incidentally, in this type of liquid crystal display device, conventionally, a ground pattern for grounding is provided on the printed wiring board 10, and this ground pattern is connected to a caulking part with the casing. By doing this, static electricity and noise countermeasures are taken for the printed wiring board 1o, but since the internal body of the LCD 1 is not grounded, the LCD 1 may malfunction (erroneous display) due to the influence of static electricity or noise.
There was a risk that this would occur.

Therefore, it is an object of the present invention to provide a liquid crystal display device in which the LCD is less susceptible to the effects of static electricity and noise.

[Means for Solving the Problems] The above-mentioned object of the present invention is to connect a group of electrode terminals formed in a terminal portion of an LCD to a printed wiring board via a group of lead patterns provided on a flexible substrate. In the liquid crystal display device, a dummy terminal independent from the electrode terminal group is provided in the terminal portion of the LCD, and a dummy pattern connected to the dummy terminal and independent from the lead pattern group is provided on the flexible substrate, and the dummy pattern This is achieved by grounding through the printed wiring board.

[Function] If the dummy terminal of the LCD is grounded via the dummy pattern of the flexible board or the ground pattern of the printed wiring board, the LCD becomes less susceptible to the effects of static electricity and noise, improving reliability. In addition, if the dummy terminals are formed from the same material as the electrode terminal group of the LCD, and the dummy patterns are formed from the same material as the lead pattern group of the flexible substrate, the manufacturing process will not be complicated and costs will increase. can.

[Example] Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a plan view of essential parts of a liquid crystal display device according to an embodiment of the present invention, and parts corresponding to those in FIG. 2 are denoted by the same reference numerals, and overlapping explanations will be omitted as appropriate.

In FIG. 1, in the terminal portion 1a of the LCDI, at positions overlapping with the flexible substrates 6, 6 placed next to each other, the same material as the electrode terminal 5 group is made of ITO film, etc., but from the electrode terminal 5 group. An independent dummy terminal 12 is provided. That is, each dummy terminal 12 is not electrically connected to the electrode terminal 5 group or the transparent electrode (not shown) and is electrically independent within the LCD 1. In addition, this terminal portion 1a
Dummy patterns 13 independent from the lead pattern 8 group are provided on each flexible substrate 6 connected to the lead pattern 8 group on both sides of the lead pattern 8 group. These dummy patterns 13 are formed by etching copper foil like the 8 group of lead patterns, but are not electrically connected to the 8 group of lead patterns or the electronic components 9 and are electrically independent within the flexible substrate 6. are doing.

Then, when a plurality of flexible substrates 6, . The anisotropic conductive sheet (
(not shown), one end of each dummy pattern 13 is connected and fixed to the nearest dummy terminal 12. In addition,
Corresponding electrode terminals 5 and lead patterns 8 are connected and fixed via this anisotropic conductive sheet.

On the other hand, connection terminals 11 are provided on the printed wiring board 10 for connecting and fixing eight groups of lead patterns to drive the LCDI.
In addition to the group, the other end of the dummy pattern 13 is connected/
An earth pattern 14 that is fixed and grounded is provided,
The dummy terminal 12 of the LCD 1 is grounded via this ground pattern 14 and the dummy pattern 13.

That is, the dummy terminal 12, the dummy pattern 13, and the ground pattern 14 take measures against static electricity and noise in the LCDI, and are designed to prevent the LCD 1 from malfunctioning (erroneous display) due to the effects of static electricity and noise.

Although not shown in the drawings, the printed wiring board 10 is provided with grounding patterns everywhere, and the grounding patterns are also connected to the caulking parts of the casing, so that not only the LCD 1 but also the printed wiring board It is less susceptible to the effects of static electricity noise by 1°.

Furthermore, in the above embodiment, the dummy terminals 12 of the LCD 1 can be formed together with the electrode terminals 5 and the transparent electrodes, and the dummy patterns 13 of the flexible substrate 6 can be formed together with the lead patterns 8. Even if we take measures against static electricity and noise for LCD1, the manufacturing process will not be complicated.
Cost increases can be avoided.

It goes without saying that the shapes of the dummy terminals 12 and the dummy patterns 13, the stage arrangement 2, etc. can be selected as appropriate.

[Effects of the Invention] As explained above, in the present invention, the dummy terminal of the LCD is grounded via the dummy pattern of the flexible board or the ground pattern of the printed wiring board.
Since the CD is less susceptible to the effects of static electricity and noise, malfunctions (erroneous displays) can be prevented, and a highly reliable liquid crystal display device can be provided.

[Brief explanation of the drawing]

FIG. 1 is a plan view of main parts of a liquid crystal display device according to an embodiment of the present invention, and FIG. 2 is a plan view of main parts of a liquid crystal display device according to a conventional example. 1...LCD (liquid crystal display element), 1a...
Terminal part, 5... Electrode terminal, 6... Flexible board, 8... Lead pattern, 10...
・Printed wiring board. 11... Connection terminal, 12... Dummy terminal, 13... Dummy pattern, 14...
・Earth pattern. Figure 1

Claims (1)

[Claims] The electrode terminal group formed in the terminal part of the liquid crystal display element is
In a liquid crystal display device connected to a printed wiring board via a group of lead patterns provided on a flexible substrate,
A dummy terminal is provided in the terminal portion of the liquid crystal display element, which is independent from the electrode terminal group, and a dummy pattern is provided on the flexible substrate, which is connected to the dummy terminal and is independent from the lead pattern group, and this dummy pattern is printed on the printed circuit board. A liquid crystal display device characterized by being grounded via a wiring board.