JP2001100237A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve display unevenness caused by plural source-driven ICs in a liquid crystal display device using a liquid crystal display circuit board and plural source-driven ICs. SOLUTION: This liquid crystal display device is provided with plural source- driven ICs, and the adjoining source-driven ICs are arranged with the pin numbers alternately inverted.

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 using a circuit board for liquid crystal display and a plurality of source driving ICs, and more particularly to a liquid crystal display device having improved display unevenness caused by a plurality of source driving ICs. is there.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device comprises a liquid crystal panel having a liquid crystal material sandwiched between two opposing glass substrates, a circuit portion for driving the liquid crystal panel, and a liquid crystal panel mounted on a back surface of the liquid crystal panel. It is a structure having a backlight arranged. In the active type liquid crystal display device, for example, a driver IC for driving a TFT (thin film transistor) built in the liquid crystal panel by inputting a signal from a source electrode wiring or a gate electrode wiring around the liquid crystal panel is mounted. Source or gate drive IC
And a bus board for supplying a power supply voltage, a ground voltage, a video signal, and the like to the IC.

In the source driving IC / gate driving IC, the liquid crystal panel is mounted on the long side / short side of the liquid crystal panel, and further connected to a bus substrate to apply an external video signal to the liquid crystal panel.

Until now, in the case of a large screen liquid crystal display device,
In many cases, source drive circuits were mounted on both sides of the liquid crystal panel. This has been determined by restrictions such as the driving method and the operating speed of the source driving IC.

However, recently, while the size of the display screen has been required to be increased, it has been required to reduce the width of a portion called a frame such as a circuit portion mounted on the periphery of the liquid crystal panel. Therefore, it is required to mount the source drive circuit on only one of the long sides of the liquid crystal panel.

In order to achieve higher performance, the gradation resolution has been changed from the conventional 6 bits / color (18 bits / pixel) to 8 bits / color (24 bits / pixel).

[0007]

In the above prior art, when the deviation of the signal output voltage between the output pins inside the source driving IC is large, a difference occurs in the effective voltage applied to the liquid crystal panel, and the difference between the effective voltages applied to the adjacent output pins is large. If it occurs between them, it will be easily visually recognized by human eyes, and it will be defective as linear luminance unevenness on the liquid crystal display device. This problem is likely to occur at the boundary between different source drive ICs. FIG. 4 is a diagram showing an output signal waveform of a conventional source driving IC, and shows a deviation of an output voltage (relative value) at a boundary between different source driving ICs. In the figure, 1 to n indicate the pin numbers of the source drive IC, and the figure shows a small number of pins, but the actual number of pins is much larger, for example, n = 380.
And so on. Although the output deviation between pins is shown in a simple pattern, it is actually a more complicated pattern.

In order to prevent this, IC manufacturers select and ship combinations in which the output deviation between adjacent output pins is small, and use them in LCD manufacturers.

However, since the liquid crystal display uses a large number of source drive ICs, it is very difficult to keep the output deviation between the ICs within a specific deviation, and it is also difficult in terms of cost. Therefore, it was difficult to improve a certain degree of unevenness.

[0010]

A liquid crystal display device according to the present invention is a liquid crystal display device in which adjacent source drive ICs are electrically symmetrically arranged to reduce the output deviation between the ICs.

[0011]

FIG. 1 is a block diagram showing an embodiment of the present invention.
It will be described based on. In the figure, 1 is a source bus substrate, 2 is a source drive IC, 2a is an odd-numbered source TC
P (TapeCarrier Package), 2b
Denotes an even-numbered source TCP, 3 denotes a gate bus substrate, 4 denotes a gate TCP, and 5 denotes a liquid crystal panel.

In the liquid crystal display device, the liquid crystal panel 5 has a TAB
A gate TCP 4 on which a driver IC is mounted is mounted by a (Tape Automated Bonding) method, and the gate TCP 4 is electrically connected to the gate bus substrate 3.

Next, the source TCP 2a and the source TCP 2b
Is mounted on one long side of the liquid crystal panel 5, a function as an active matrix type liquid crystal display device can be realized.

The two types of sources TCP, 2a and 2b have different wiring patterns, respectively, TAB (Tape A).
(automated bonding). FIG. 3 is a sectional view of two types of source driving TCPs 2a and 2b. Source TCP2a is a source drive IC
2 bonding wiring pattern on the front side (upper surface shown)
The source TCP 2b has the same pattern on the back side. In the bonding wiring patterns of the source TCPs 2a and 2b, the pin number wirings are symmetrical in the illustrated state. The source drive IC2 of the source TCP2a is TA
B, and the source drive IC 2 of the source TCP 2b is bonded to the back side of the TAB. Therefore, the source drive IC 2 is wired to the source TCPs 2a and 2b with the front and back alternately reversed.

The means for mounting the source drive IC is as follows. First, the source drive IC 2 is connected to the liquid crystal panel 7.
Temporary crimping is performed with a TAB bonder at odd-numbered mounting positions on the long side. Next, the source drive IC 2 is temporarily crimped to an even-numbered mounting position on the long side of the liquid crystal panel 7. Thereafter, odd-numbered and even-numbered odd-numbered source TCPs 2a and even-numbered source TCPs 2b are formed. The source drive ICs 2 are completely pressure bonded together. FIG. 2 is a diagram showing a signal output waveform of the source drive IC in the source TPC mounted as described above. Here, the source drive IC 2 uses a chip manufactured from the same wafer. The source drive IC 2 manufactured from the same wafer has a small difference between chips,
Although there is an output deviation between pins within the same IC, the output deviation between the same pins of different ICs is small.
Therefore, when the source TPCs 2a and 2b are arranged as described above, the pin numbers are set to 1, 2、１n, and 1 and 1 or n and n are arranged adjacently, and those having small output deviations are arranged adjacently. In addition, the brightness difference at the boundary between ICs can be reduced.

[0016]

According to the liquid crystal display device of the present invention, the output deviation between the adjacent source drive ICs is reduced by mounting the adjacent source drive ICs electrically symmetrically, and the linear The unevenness is almost eliminated. In addition, since a silicon chip manufactured from the same wafer can be used to realize a source driving IC that is electrically symmetric, an increase in cost can be suppressed.

In realizing the present invention, it can be easily mounted using a conventional device.

[Brief description of the drawings]

FIG. 1 is a plan view of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an output signal waveform of a source drive IC that can be realized by the present invention.

FIG. 3 is a sectional view of a source TPC for realizing the present invention.

FIG. 4 is a diagram illustrating an example of an output signal waveform of a conventional source drive IC.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Source bus board 2 Source drive IC 2a Source TCP (odd number) 2b Source TCP (even number) 3 Gate bus board 4 Gate TCP 5 Liquid crystal panel

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA49 GA50 GA51 GA57 GA60 JA24 MA33 MA35 NA05 NA25 NA27 NA29 PA06 5C006 BB16 BC02 BC11 BC23 EB05 FA22 5C080 AA10 BB05 DD05 FF11 JJ05 JJ06

Claims (2)

[Claims] 1. A liquid crystal display device comprising a plurality of source driving ICs, wherein adjacent ones of the source driving ICs are arranged with their pin numbers alternately inverted. 2. A method for mounting the source drive IC, comprising:
TAB having a bonding wiring pattern on the front side,
2. The liquid crystal display device according to claim 1, wherein TAB having a bonding wiring pattern on the back side surface is used.