JPH06102523A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which enables sure terminal connections without a leak or open circuit even if the data-line side pitch of a liquid crystal display panel becomes small. CONSTITUTION:This liquid crystal display device is equipped with a liquid crystal display panel B, a thin plate type tape carrier package A which sends a signal from a signal transmitter to a liquid crystal display panel B, and an anisotropic conductive film 1 which connects electrode terminals 7 of the liquid crystal display panel B to terminals of the tape carrier package A; and insulating coated conductive particles 4 formed by coating conductive particles 3 with insulating films 11 and conductive particles 3 which are not coated with insulating films 11 are mixed together in the anisotropic conductive film 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device used in, for example, a portable word processor, a personal computer or the like,
In particular, the present invention relates to a liquid crystal display device in which an anisotropic conductive film for connecting an electrode terminal of a liquid crystal display panel and a terminal of a TCP (tape carrier package) is improved.

[0002]

2. Description of the Related Art In recent years, information transmission devices such as word processors and personal computers have been personalized, and in particular, liquid crystal display devices can be driven at a low voltage, so that they can be miniaturized relatively easily and very often. It has been used. In addition, very recently, there is a strong demand for color display of liquid crystal display devices,
Some have begun to commercialize.

However, when performing color display on a liquid crystal display device, one display pixel is R, G, B, unlike black and white display.
Since it is composed of three color parts (red, green, blue), if you try to display with a simple matrix method, for example,
When constructing a display screen of 640 × 480 pixels, the number of terminals on the data line side (segment side) of the liquid crystal display panel is 640 × 3, that is, three times as large as that of a monochrome display panel. It will be 1920. Therefore, the connection pitch between the electrode terminals on the data line side of the liquid crystal display panel and the terminals of the TCP (tape carrier package) is
It is about 1/3 of the black and white display.

This reduction in connection pitch technically makes the terminal connection between the liquid crystal display panel and TCP technically difficult.
Therefore, in order to suppress the reduction of the connection pitch, the electrode terminals on the data line side (segment side) are distributed up and down every other electrode, and the connection pitch of the electrode terminals on the segment side is about 1 It was set to (1/3) × 2.

However, as in the case of black and white display, the scanning line side
480 (common side) electrode terminals are
It becomes impossible to drive by dividing into 0 (1/240 duty) each, and 480 electrode terminals are driven for 4 times in a predetermined period.
There was no choice but to drive 80 lines each (1/480 duty).

Regarding the display quality of the liquid crystal display device, the smaller the number of electrodes on the scanning line side (common side) that must be driven in a predetermined period, the longer the on-time that can be assigned to one scanning line side electrode. Therefore, the contrast is improved, the response speed is increased, the crosstalk is reduced, and the display quality is improved.

That is, the display quality of 1/480 duty driving is inferior to that of 1/240 duty driving.
The conventional simple matrix type color liquid crystal display device, which has been forced to adopt the 480 duty driving system, cannot always satisfy the user sufficiently.

The structure of the anisotropic conductive film used for the connection between terminals of the liquid crystal display device and the reason why the connection between the terminals becomes difficult when the connection pitch between the terminals becomes small will be described in detail below. Explained.

Generally, an anisotropic conductive film used in a liquid crystal display device is formed by blending a conductive particle 38 with a thermoplastic resin or a thermosetting resin or a mixture 37 thereof as shown in FIG. is there.

As shown in FIG. 2, the anisotropic conductive film 31 is formed on the electrode terminal 33 of the liquid crystal display panel 32 and the terminal 36 of the TCP 35.
The anisotropic conductive film 31 is sandwiched between the anisotropic conductive film 31 and the anisotropic conductive film 31 by applying heat and pressure to the anisotropic conductive film 31.
3 and the terminal 36 of the TCP 35 can be fixed and adhered. Then, when heat and pressure are applied to the anisotropic conductive film 31, the conductive particles 38 included in the anisotropic conductive film 31 are sandwiched between the electrode terminals 33 and 36 and pressure-bonded. In this way, the electrode terminal 33 and the terminal 36 can be electrically connected.

However, in the anisotropic conductive film 31 of the liquid crystal display device, the conductive particles 38 are connected between the electrode terminals 33 as the pitch of the electrode terminals 33 of the liquid crystal display panel 32 becomes narrower. There is a problem that a phenomenon (leakage) occurs in which pixels other than the pixel to be displayed are displayed. Further, if the number of the conductive particles 38 is reduced in order to eliminate the leak, there is a problem that a phenomenon (open) in which a pixel to be displayed does not display occurs.

Therefore, in order to solve the above problem, FIG.
As shown in, the conductive particles 38 of the anisotropic conductive film 31.
There is a liquid crystal display device in which the leak is eliminated by replacing the conductive particles 40 with the insulating coated conductive particles 42 in which the insulating coating 41 is coated.

However, in the above-mentioned liquid crystal display device, the insulating film 41 is not sufficiently removed only by applying the temperature and pressure conventionally used conventionally to the anisotropic conductive film 31, so that the terminals which should not be connected are not connected. However, there is a problem in that the conduction resistance between the terminals to be connected becomes relatively large and the display function deteriorates. Further, in order to solve this problem, if a higher temperature and a higher pressure than the conventional one are applied to the anisotropic conductive film 31, the liquid crystal display device may be damaged, such as the panel glass of the liquid crystal display panel 32 breaking. There is a problem of lack of mass productivity.

[0014]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a liquid crystal display device capable of reliable terminal connection without causing leakage or opening even if the pitch of the data line side of the liquid crystal display panel becomes small. To provide.

[0015]

In order to achieve the above object, a liquid crystal display device of the present invention transmits a signal from a liquid crystal display panel and a signal transmitting device for transmitting a signal to the liquid crystal display panel to the liquid crystal display panel. And a anisotropic conductive film for connecting the electrode terminals of the liquid crystal display panel and the terminals of the tape carrier package to each other, and the anisotropic conductive film is provided with an insulating coating on conductive particles. It is characterized in that the coated insulating coated conductive particles and the conductive particles not coated with the insulating coating are mixed.

[0016]

The anisotropic conductive film is subjected to thermocompression bonding under normal thermocompression bonding conditions, so that the conductive particles of the anisotropic conductive film form the electrode terminals of the liquid crystal display panel and the tape carrier package to be connected to the electrode terminals. It is sandwiched between terminals to realize electrical connection between the electrode terminals and the terminals. In addition, the insulating coated conductive particles of the anisotropic conductive film are present between the terminals that should not be electrically connected to each other to sufficiently maintain the electrical insulation between the terminals.

[0017]

The present invention will be described in detail below with reference to the embodiments shown in the drawings.

As shown in FIG. 1, the electrode terminal 7 of the liquid crystal display panel B of the liquid crystal display device of this embodiment has ITO (indium tin oxide) on the liquid crystal display panel glass 8.
Was vapor-deposited and etched. The pitch of the electrode terminals 7 is 85 μm.

On the other hand, as a tape carrier package A for transmitting a signal from a signal transmitting device for transmitting a signal to the liquid crystal display panel B to the liquid crystal display panel B, an upilex film 5 (thickness of 75 μm) and a copper foil are used. It was used after being attached and etched. The etched copper foil has a tin-plated surface and an electrode pitch of 8
It becomes the terminal 6 of 5 μm.

The anisotropic conductive film 1 connecting the electrode terminals 7 of the liquid crystal display panel B and the terminals 6 of the tape carrier package A contains a thermoplastic resin and a thermosetting resin at a ratio of about 1: 1. In the mixed resin 2 prepared by mixing the above, the insulating coated conductive particles 4 in which the conductive particles 3 are coated with the insulating coating 11 and the conductive particles 3 not coated with the insulating coating 3: 1
The mixture is added in the ratio of. The total weight of the insulating coated conductive particles 4 and the conductive particles 3 is set to 15% of the weight of the mixed resin 2.
That is, the particles 4 and 3 have a ratio of 1 to the mixed resin 2.
Blended to be 5 wt% (weight percent).

The anisotropic conductive film 1 has electrode terminals 7 of the liquid crystal display panel B and terminals 6 of the tape carrier package A.
Then, thermocompression bonding was performed from above the terminal 6 with a pulse heat thermocompression bonding machine under the thermocompression bonding conditions of 200 ° C. and 30 kg / cm ² .

By thermocompression-bonding the anisotropic conductive film 1 under the normal thermocompression bonding conditions, the conductive particles 3 of the anisotropic conductive film 1 are transferred to the electrode terminals 7 of the liquid crystal display panel B as shown in FIG. And the terminal 6 of the tape carrier package A to be connected to the electrode terminal 7,
The electrical connection between the terminal 6 and the terminal 6 is surely realized. Also,
The insulating coated conductive particles 4 of the anisotropic conductive film 1 are between terminals that should not be electrically connected (for example, between electrode terminals 7 and 7, terminals 6 and 6, or electrode terminals that do not face each other). 7 and the terminal 6) to sufficiently maintain the electrical insulation between the terminals. Therefore, according to this embodiment, even if the pitch between the electrode terminals 7 and 7 is reduced, it is possible to prevent the occurrence of leakage between the electrode terminals 7 and 7, and to prevent the leakage between the electrode terminals 7 and 6. It is possible to prevent the occurrence of defective conduction.

Therefore, according to this embodiment, for color display, the number of the electrode terminals 7 is increased and the pitch of the liquid crystal display panel B on the data line side is reduced to 10 lines / mm to 12 lines / mm. Even then, it is possible to realize a liquid crystal display device capable of reliable terminal connection without causing leakage or opening.

Further, the above-described embodiment shown in FIG. 1 (the anisotropic conductive film contains the insulating coated conductive particles and the conductive particles) and the conventional example shown in FIG. 2 (the anisotropic conductive film contains only the conductive particles). .) Figure 3
The conventional example shown in (the anisotropic conductive film contains only insulating coated conductive particles) was subjected to an energization test. In the above example, no leakage occurred in one of the 10 tested units, and the connection resistance was It was stable at less than 1 ohm.

On the other hand, in the conventional example of FIG. 2, the connection resistance was stable at 1 ohm or less, but in 10 out of 10 tested, leakage occurred in 1 to 10 places. The cause of the leak was that the conductive particles were connected at a location where the conductive particles were not uniformly dispersed, or the flow of the resin was blocked by a foreign substance to collect the conductive particles.

Further, in the conventional example of FIG. 3, none of the 10 units tested leaked, but the connection resistance was relatively high and was 4 to 6 ohms.

As is apparent from the above experiment, according to this embodiment, the number of the electrode terminals 7 is increased and the pitch of the liquid crystal display panel B on the data line side is 10 lines / mm for color display. Unlike the conventional example, a liquid crystal display device capable of reliable terminal connection without causing leakage or opening can be realized even if it is reduced to ~ 12 lines / mm.

Therefore, 1/240 duty driving color display is possible, and a color liquid crystal display device having excellent display quality can be realized.

In the above embodiment, the insulating coated conductive particles 4 are used.
And the ratio of the conductive particles 3 to 3: 1 and the particles 4,
3 is 15 wt% of resin 2 of anisotropic conductive film 1
However, since the optimum values of these ratios differ depending on the conductive particles, the type of the insulating coat film, the resin 2, and the like, they are not limited to the above values.

[0030]

As is apparent from the above, in the liquid crystal display device of the present invention, the anisotropic conductive film connecting the electrode terminals of the liquid crystal display panel and the terminals of the tape carrier package is coated with conductive particles and an insulating coating. The insulating coated conductive particles and the conductive particles not coated with the insulating coating are mixed.

Therefore, the anisotropic conductive film is thermocompression-bonded under normal thermocompression bonding conditions, whereby the conductive particles of the anisotropic conductive film are connected to the electrode terminals of the liquid crystal display panel and the tape carrier to be connected to the electrode terminals. It is sandwiched between the terminals of the package and realizes reliable electrical connection between the electrode terminals and the terminals. In addition, the insulating coated conductive particles of the anisotropic conductive film are present between the terminals that should not be electrically connected to each other to sufficiently maintain the electrical insulation between the terminals.

Therefore, according to the present invention, even if the number of electrode terminals is increased and the pitch on the data line side of the liquid crystal display panel is reduced for color display, unlike the conventional example, leakage or open is caused. It is possible to realize a liquid crystal display device capable of reliable terminal connection.

Therefore, 1/240 duty driving color display is possible, and a color liquid crystal display device having excellent display quality can be realized.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of an embodiment of a liquid crystal display device of the present invention.

FIG. 2 is a sectional view of a conventional example.

FIG. 3 is a sectional view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Anisotropic conductive film, 2 ... Resin, 3 ... Conductive particle, 4 ... Insulating coating conductive particle, 5 ... Upilex film, 6 ... Terminal,
7 ... Electrode terminals, 8 ... Liquid crystal display panel glass, 11 ... Insulating coating.

Claims (1)

[Claims] 1. A liquid crystal display panel, a thin-plate tape carrier package for inputting a signal from a signal transmitting device for transmitting a signal to the liquid crystal display panel to an electrode terminal of the liquid crystal display panel, and a liquid crystal display panel of the liquid crystal display panel. An anisotropic conductive film for connecting the electrode terminals to the terminals of the tape carrier package, wherein the anisotropic conductive film has conductive particles coated with an insulating coating, and conductive particles not coated with the insulating coating. A liquid crystal display device characterized by being mixed.