JPH04333020A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To eliminate a difference of the brightness of a display at the border between adjacent scanning electrode groups which are driven mutually different scanning-side integrated circuits. CONSTITUTION:This device is equipped with 1st scanning-side integrated circuits IC1 and IC3 which drive one of adjacent scanning electrode groups and have output terminals for 1st output positioned nearby internal power terminals as to wiring. Further the device is provided with a 2nd scanning-side integrated circuit IC 2 which drives the other scanning electrode group and has an output terminal for 1st output positioned at a distance from its internal power terminal at to wiring. The scanning directions of those integrated circuits are set to an up-down direction and the bias voltages are equalized.

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 with high display quality.

0002

2. Description of the Related Art Conventionally, a liquid crystal display device using a plurality of integrated circuits is shown in Japanese Unexamined Patent Publication No. 62-55697 as shown in FIG. 51 is a liquid crystal cell. 52, 53 and 54 are respectively from X1 to X80 and from X81 to X16
This is a scan electrode group consisting of scan electrodes from X161 to X240. IC26, IC27, and IC28 are scan-side integrated circuits that drive each scan electrode group 52, 53, and 54, respectively. And both output terminals O1 to O8
0 and a power terminal 55, and used the same integrated circuit. IC29, IC30, IC31, and IC32 are signal-side integrated circuits that drive signal electrodes formed in the liquid crystal cell 51, respectively.

0003

In the above liquid crystal display device, the relationship between the position of the scanning electrode and the liquid crystal drive voltage value will be explained with reference to the graph of FIG. 5(c). It was found that there was a difference of 0.3V in the liquid crystal drive voltage values between X80 and X81 and between X160 and X161. The reason is that as the number of pixels increases in recent large-sized liquid crystal display devices, the number of IC output terminals increases, and the power supply line is formed as a bus line. Therefore, inside the scanning integrated circuits IC26, IC27, and IC28, the circuit resistance due to the bus line increases and the output voltage value gradually decreases from the output terminal O1 to O80. This difference in voltage value creates a difference in display brightness,
Boundary lines on the display were visible between the above-mentioned scanning electrodes X80 and X81 and between X160 and X161, which degraded the display quality. The present invention has been made in view of the above-mentioned drawbacks, and is intended to eliminate the boundary line on display.

0004

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a liquid crystal cell having a plurality of scanning electrode groups and signal electrode groups arranged in a matrix, and one of the adjacent scanning electrode groups. a first scanning-side integrated circuit whose output terminal that outputs the first output is located closer in wiring to the built-in power terminal than the other output terminals; and the other adjacent scanning electrode group. The output terminal that is driven and outputs first is located further away from the built-in power terminal in terms of wiring than other output terminals, and is in the same top-to-bottom scanning direction as the first scanning-side integrated circuit. A second scanning-side integrated circuit having a bias voltage is provided.

[0005]

[Operation] In the first scanning integrated circuit, the present invention positions the first output terminal close to the power terminal in terms of wiring and scans from top to bottom. The lower one of the scanning electrode groups is, the lower the liquid crystal drive voltage value becomes. In the second scanning-side integrated circuit, the first output terminal is located far away from the power terminal in terms of wiring, and scanning is performed from top to bottom. The voltage value decreases. Therefore, the difference in liquid crystal drive voltage values is reduced near the two scanning electrode groups described above, and the difference in display brightness is eliminated.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the block diagram of FIG. Transparent scanning electrodes X1 to X240 are made of ITO or the like, and are formed inside one substrate made of a transparent glass plate or the like. 1, 2, 3 are respectively X1 to X80, X81 to X160, X16
This is a scan electrode group consisting of scan electrodes from 1 to X240. Transparent signal electrodes Y1 to Y320 are made of ITO or the like, and are formed inside the other substrate made of a transparent glass plate or the like so as to be orthogonal to the scanning electrodes X1 to X240. Signal electrode groups 4, 5, 6, and 7 each include 80 signal electrodes. Reference numeral 8 denotes a liquid crystal cell in which liquid crystal is sealed between one of the substrates and the other substrate. In this way, the scanning electrode groups 1, 2, and 3 are arranged in a matrix with the signal electrode groups 4, 5, 6, and 7. IC1 is a first scanning integrated circuit that drives one of the adjacent scanning electrode groups 1 and 2. The first scanning integrated circuit IC1 has a scanning direction set from top to bottom, that is, from scanning electrodes X1 to X80, and has 80 output terminals from the first output terminal O1 to the last output terminal O80. have 9 is a power terminal, which is located inside the IC 1 and is located close to the first output terminal 01 in terms of wiring, and has a bias voltage of 1
0 is supplied. IC2 is a second scanning-side integrated circuit that drives the other of the adjacent scanning electrode groups 1 and 2, that is, the scanning electrode group 2. The second scanning-side integrated circuit IC2 has a scanning direction set from top to bottom, that is, from scanning electrodes X81 to X160, and has 80 output terminals from the first output terminal P80 to the last output terminal P1. have Reference numeral 11 denotes a power terminal, which is provided inside the IC 2 and is located far away in terms of wiring from the output terminal P80 that outputs first, and is supplied with a voltage having the same value as the bias voltage 10 described above. IC3 is a first scanning side integrated circuit, drives the scanning electrode group 3, and has the same structure and function as IC1. I
C4, IC5, IC6 and IC7 are signal electrode group 4, respectively.
, 5, 6, and 7, and for example, Hitachi's HD61104A can be used. 1
Reference numeral 2 denotes a power supply circuit, which applies a plurality of bias voltages and input voltages to each of the integrated circuits IC1 to IC7. That is, the first and second scanning side integrated circuits IC1, IC2, IC3
A bias voltage 10 consisting of four types of voltages is applied to the signal side integrated circuits IC4, IC5, IC6, and IC7, and bias voltages consisting of four different voltages are applied to the signal side integrated circuits IC4, IC5, IC6, and IC7. The control device 13 receives the image signal 14 and sends the signal 15 to the first and second scanning integrated circuits IC1, IC2, and IC3.
and the signal side integrated circuits IC4, IC5, IC6, IC
7 is given a signal 16 different from the signal 15. This signal 15
specifies the scanning timing for the scanning electrodes from X1 to X240, and the signal 16 gives an image signal to the signal electrodes from Y1 to Y320.

Next, the first scanning integrated circuit IC1 used in this embodiment will be explained with reference to the block diagram of FIG. This IC1 is HD61105A manufactured by Hitachi. Reference numeral 17 denotes a first drive circuit, which consists of four sets of MOS and gates, and its output side is connected to the output terminal O1. 18 is an 80th drive circuit connected to the output terminal O80. A bias voltage line 19 supplies a bias voltage 10 consisting of V1, V2, V5, and V6 from the first drive circuit 17 to the eightieth drive circuit 18 via a bus line. 20 is a shift register, which consists of 80 registers from the first register 21 to the 80th register 22. 9 is the output terminal O that outputs first than the other output terminals O2 to O80.
This is a power terminal located close to 1 in terms of wiring. Then, the operation of this IC1 will be explained. A bias voltage 10 and an input voltage 23 consisting of VCC, GND, and VEE are supplied by the power supply circuit 12 of FIG. A signal 15 consisting of a clock signal CL, a data signal D, and a polarity inverted signal M is input to IC1. That is, the clock signal CL is inputted from the first register 21 to the 80th register 22 via logic (1). Since the switching terminal SHL is connected to VCC, the data signal D is sequentially transferred from the first register 21 to the eighth register 21.
The data is shifted to the register 22 of 0. The polarity inversion signal M gives an H or L signal to one terminal of each gate, and the shift register 20 gives an H or L signal to the other terminal of each gate. The combination of these signals each outputs one bias voltage 10 to the output terminal O1.
to O80, respectively. As described above, the output terminals O1 to O80 are scanned in order. Also, this IC1
From the output terminals O1 to O80, the bias voltage line 19 connecting the power terminal 9 and the drive circuit becomes longer and the wiring resistance increases as it goes downward. Therefore, the output voltage decreases as it goes downward from output terminal O1 to O80.

Next, the second scanning side integrated circuit IC2 used in this embodiment will be explained with reference to the block diagram of FIG. 17
1 is a first drive circuit whose output side is connected to the output terminal P80, and 18 is an 80th drive circuit connected to the output terminal P1. 11 than the other output terminals P1 to P79,
This is a power terminal located far away in terms of wiring from the output terminal P80 that outputs first. Then, the operation of this IC2 will be explained. Clock signal CL is input from the first register 21 to the 80th register 22 via logic (1). Since the switching terminal SHL is connected to GND, the data signal D is sequentially transferred from the 80th register 22 to the first register 2.
Data is shifted up to 1. The data signal D and the polarity inversion signal M are input to each gate, and one bias voltage 10 is supplied to the output terminals O80 to O1, respectively, and the signals are sequentially scanned from top to bottom. And this IC
The bias voltage line 19 connecting the power terminal 11 and the drive circuit becomes longer and the wiring resistance increases as it goes upward from the output terminals P1 to P80. Therefore, the output voltage decreases as it goes up from output terminal P1 to P80. Furthermore, since the bias voltage 10 to the first and second scanning integrated circuits IC1 and IC2 is the same, the output terminals O1 and P of each of IC1 and IC2 are the same.
The output voltage from 1 is the same. Furthermore, in the liquid crystal display device according to this embodiment, the relationship between the position of the scanning electrode and the liquid crystal driving voltage value will be explained with reference to the graph of FIG. 5(a). The horizontal axis shows the position of the scanning electrode, and the vertical axis shows the liquid crystal drive voltage value (V)
In other words, it is the difference between the voltage value applied to the scanning electrode and the voltage value applied to the signal electrode. In this figure, it is the first scanning integrated circuit IC1 that drives the scanning electrode group 1, so
As mentioned above, as you go down from scanning electrode X1 to X80,
The liquid crystal drive voltage value decreases, and the difference is 0.3V. Since it is the second scanning-side integrated circuit IC2 that drives the scanning electrode group 2, the liquid crystal driving voltage value decreases as it goes upward from scanning electrodes X160 to X81, and the difference is 0.3V. Furthermore, as described above, the liquid crystal drive voltage values at scan electrodes X1 and X160 are the same. Therefore, scanning electrodes X80 and
The liquid crystal driving voltage values 81 are both 22.7 V, and there is no voltage difference at the boundary between scanning electrode groups 1 and 2. Similarly, since there is no voltage difference at the boundary between scanning electrode groups 2 and 3, the boundary line on the display is no longer visible.

Next, a second embodiment of the present invention will be described with reference to the block diagram of FIG. This embodiment relates to a 400 dot x 640 dot liquid crystal display device having a larger number of pixels than the first embodiment. 24, 25, 26, 27 are respectively X1 to X1
00, X101 to X200, X201 to X
300, a scan electrode group consisting of scan electrodes from X301 to X400. 28 to 35 constitute an upper screen and are a signal electrode group consisting of 80 signal electrodes, and 36 to 43 constitute a lower screen and are a signal electrode group consisting of 80 signal electrodes.
This is a signal electrode group consisting of four signal electrodes. 44 is a liquid crystal cell, which includes a group of scanning electrodes 24 to 27 and a group of scanning electrodes 28 to 4.
Up to three signal electrode groups are arranged in a matrix. IC8 is a first electrode that drives scanning electrode groups 24 and 26 in parallel.
The scanning side integrated circuit IC8 is, for example, Toshiba's T9822.
-TC can be used. The scanning direction of this IC 8 is set from top to bottom, and it has output terminals O1 to O100 that output first. A power terminal 9 is provided inside the IC 8, is located close to the output terminal O1 in terms of wiring, and is supplied with a bias voltage 10. I
C9 is a second scanning-side integrated circuit IC9 that drives the scanning electrode groups 25 and 27 adjacent to the scanning electrode groups 24 and 26 in parallel. The scanning direction of this IC9 is set from top to bottom, and it has output terminals P100 to P1 that output first. And 11 is a power terminal, and the IC
Output terminal P100 provided inside 9 and outputting first
It is located far away in terms of wiring, and is supplied with a voltage having the same value as the bias voltage 10 described above. IC10 to IC17 are signal side integrated circuits that drive signal electrode groups 28 to 35, respectively, and IC18 to IC25 are signal side integrated circuits that drive signal electrode groups 36 to 43, respectively.
104A can be used. Other parts indicated by the same numbers as those in the first embodiment are the same. With this configuration, as described in the first embodiment above,
The output voltage decreases as it goes from output terminal P1 to P100. Further, the scanning direction is from top to bottom, and the bias voltage 10 input to IC8 and IC9 is the same. Furthermore, in this example, the liquid crystal driving voltage value with respect to the position of the scanning electrode is shown in FIG.
This will be explained using the graph b). In this figure, scanning electrodes X1, X200, X201, and X4
The liquid crystal driving voltage at 00 is 24.0V, and the liquid crystal driving voltage at scanning electrodes X100, X101, X300, and X301 is 23.7V. Therefore, the scanning electrode group 24,
The voltage difference at the boundaries of 25, 26, and 27 disappears.

0010

[Effects of the Invention] As described above, in the first scanning integrated circuits IC1, IC3, and IC8, the first output terminal O1 is located close to the power terminal 9 in terms of wiring. Since it scans downward, these integrated circuits IC1, IC3, I
One adjacent scanning electrode group 1, 3 driven by C8
, 24, and 26, the liquid crystal drive voltage value decreases as it goes lower. In the second scanning integrated circuits IC2 and IC9, the first output terminals P80 and P100 are located far away from the power terminal 11 in terms of wiring, and scanning is performed from top to bottom, so the other scanning electrode group 2 , 25, and 27, the liquid crystal drive voltage value decreases as it goes upward. Therefore, if the two scanning electrode groups mentioned above, for example 1
The difference in driving voltage decreases near the vicinity of and 2, and the difference in display brightness disappears. Furthermore, the liquid crystal drive voltage value at the top scan electrode X161 of one adjacent scan electrode group 3 and the liquid crystal drive voltage value at the bottom scan electrode X160 of the other scan electrode group 2 are the same. be. This is because the bias voltages driving the two scan electrodes X160 and X161 are the same. Therefore, the difference in drive voltage values is reduced in the vicinity of the two scanning electrode groups 2 and 3, so there is no difference in brightness on display. Therefore, high display quality can be provided. Furthermore, as mentioned above, in the conventional liquid crystal display device, as shown in FIG. 6 and FIG. 5(c),
and X81, and between X160 and X161 0.3
There is a difference in the driving voltage value of V. This is a difference in the initial position of the scanning electrode, and since recent large liquid crystal display devices have a large number of pixels, the scanning electrode becomes long. Therefore, the voltage drop at the end of the scan electrode becomes even larger due to the load on the scan electrode itself. Therefore, eliminating the difference in drive voltage values between adjacent scanning electrodes as in the present invention has a great effect in eliminating the difference in brightness.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a first scanning integrated circuit IC1 used in the first embodiment of the present invention.

FIG. 3 is a block diagram of a second scanning-side integrated circuit IC2 used in the first embodiment of the present invention.

FIG. 4 is a block diagram of a liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a graph showing the liquid crystal driving voltage value versus the position of the scanning electrode. (a) shows the first embodiment, (b) shows the second embodiment, and (c) shows the characteristics of a conventional liquid crystal display device.

FIG. 6 is a block diagram of a conventional liquid crystal display device.

[Explanation of symbols]

1, 2, 3, 24, 25, 26, 27 Scanning electrode group 4
, 5, 6, 7, 28-43 Signal electrode group 8, 44
Liquid crystal cell O1, P80, P100
First output terminal 9, 1
1
Power terminal IC1, IC3, IC8
First scanning integrated circuit IC2, IC9
Second scanning side integrated circuit

Claims (1)

[Claims] 1. A liquid crystal cell having a plurality of scanning electrode groups and signal electrode groups arranged in a matrix, and an output terminal that drives one of the adjacent scanning electrode groups and outputs the first output. A first scanning integrated circuit located closer to the built-in power terminal in terms of wiring than the terminal, and an output terminal that drives the other adjacent scanning electrode group and outputs first, and a second scanning-side integrated circuit located far away from the built-in power terminal in terms of wiring and having the same top-to-bottom scanning direction and the same bias voltage as the first scanning-side integrated circuit. A liquid crystal display device featuring: