JPH09211475A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent crosstalk level difference from occurring by keeping a cell voltage constant. SOLUTION: This device is provided with a substrate 2 having plural scanning electrodes CL1-CLN, a liquid crystal panel 1 in which a substrate 3 having plural signal electrodes SL1-SLM is placed facing the scanning electrodes CL by interposing a liquid crystal layer so that the scanning electrodes and the signal electrodes cross each other, a scanning circuit 4 to apply a scanning voltage to an end of the scanning electrodes CL, and a signal circuit 6 to apply a signal voltage to the signal electrodes, and a desired voltage is applied to a cell specified according to a cross point of the scanning electrodes CL and the signal electrodes. In this case, a signal voltage correction means 8 to correct the signal voltage is provided so that a voltage applied to the signal electrodes SL is increased stepwise as it goes from an end side of the scanning electrodes CL to the other end side.

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 having a voltage correction function for compensating for a voltage drop along the extension direction of scan electrodes.

[0002]

2. Description of the Related Art A conventional liquid crystal display device will be described with reference to the block diagram shown in FIG. In this figure, 2
Reference numeral 0 denotes a liquid crystal panel, which includes a first substrate 21 having a plurality of scanning electrodes CL and a second substrate 2 having a plurality of signal electrodes SL.
2, the first and second substrates 21 and 22 are arranged to face each other with a liquid crystal layer interposed therebetween so that the scanning electrodes CL and the signal electrodes SL intersect at approximately 90 degrees.
The plurality of scan electrodes CL and the signal electrodes SL are composed of transparent electrodes such as ITO. Reference numeral 23 is a scanning circuit for applying a scanning voltage to one end of the scanning electrodes, and a plurality of scanning drive ICs 2 arranged at one edge of the liquid crystal panel 20 in the left-right direction.
4 is provided. Reference numeral 25 denotes a signal circuit for applying a signal voltage to one end of the signal electrode, and a plurality of signal drive ICs 26 arranged at one edge in the vertical direction of the liquid crystal panel 20 (both ends when the screen is divided into upper and lower parts). Is equipped with. The scanning circuit 23 and the signal circuit 25 operate by being supplied with a drive power supply, a bias voltage, a timing signal, an image signal (only a part of the bias voltage is shown), etc. from a circuit (not shown), and of the plurality of bias voltages supplied. A predetermined bias voltage is selectively applied to the scan electrodes CL from among the signal electrodes SL.
By applying a predetermined bias voltage to
A desired voltage is applied to the cell defined by the intersection of the scan electrode CL and the signal electrode SL. The display state can be controlled for each cell by changing the state of liquid crystal molecules by the effective voltage applied to the cell.

[0003]

With the recent increase in the size of the display screen, the conventional liquid crystal display device described above has the following problems.
A difference in crosstalk level occurs in the left-right direction of the screen (extending direction of the scanning electrodes), which causes a problem in display quality. Generally, the crosstalk tends to increase as the distance from the side of the panel on which the scanning drive IC is arranged increases. When the cause was examined, the resistance value of the scan electrode was considered as one of the factors. That is, the voltage drop increases along the extension direction of the scan electrode, and as a result, the point where a difference appears in the voltage applied to the cell along the extension direction of the scan line (left and right direction of the panel) causes a crosstalk level difference. It was considered to be one of the factors.

In view of the above points, an object of the present invention is to keep the voltage applied to the cell constant and suppress the occurrence of a crosstalk level difference.

[0005]

According to the present invention, a liquid crystal is provided in which a substrate having a plurality of scanning electrodes and a substrate having a plurality of signal electrodes are opposed to each other with a liquid crystal layer interposed so that the scanning electrodes and the signal electrodes intersect each other. A panel, a scanning circuit for applying a scanning voltage to one end of the scanning electrode, and a signal circuit for applying a signal voltage to the signal electrode, and a desired voltage for a cell defined by an intersection of the scanning electrode and the signal electrode. In the liquid crystal display device that applies the voltage, a signal voltage correction unit that corrects the signal voltage so that the voltage applied to the signal electrode gradually increases from one end side to the other end side of the scanning electrode is provided. Characterize.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the block diagram shown in FIG. In this figure, reference numeral 1 denotes a liquid crystal panel, which has a plurality of scanning electrodes CL1 to CLN.
The first substrate 2 having a plurality of signal electrodes SL1 to SL
The second substrate 3 having M is provided, and the first and second substrates 2 and 3 are connected to the scan electrodes CL1 to CLN and the signal electrode SL1.
The SLMs are intersected at about 90 degrees, and the liquid crystal layer is interposed therebetween to face each other. Multiple scan electrodes CL
1 to CLN and the signal electrodes SL1 to SLM are composed of transparent electrodes such as indium oxide thin film (ITO),
It forms a so-called simple matrix. The liquid crystal layer can be formed of, for example, a super twisted nematic liquid crystal layer.

A scanning circuit 4 applies a scanning voltage to one end of the scanning electrodes CL1 to CLN, and includes a plurality of scanning drive ICs 5 arranged at one edge of the liquid crystal panel 1 in the left-right direction. Reference numeral 6 denotes a signal circuit that applies a signal voltage to one end of the signal electrodes SL1 to SLM, and one edge in the vertical direction of the liquid crystal panel 1 (both ends when the screen is divided into upper and lower parts).
Is provided with a plurality of signal drive ICs 7. The scanning circuit 4 and the signal circuit 6 are supplied with a driving power supply, a bias voltage, a timing signal, an image signal and the like (only a part of the bias voltage V1 and V0 is shown in the drawing) from a circuit not shown. And selectively applying a predetermined bias voltage to the scan electrodes CL1 to CLN from among a plurality of bias voltages supplied thereto and applying a predetermined bias voltage to the signal electrodes SL1 to SLM. Applies a desired voltage to the cell defined by the intersection of the scan electrode and the signal electrode. The display state is controlled for each cell by changing the state of liquid crystal molecules by the effective voltage applied to the cell.

In order to compensate the voltage drop due to the resistance value increasing along the extension direction of the scan electrodes CL1 to CLN, the signal circuit 6 has a direction from one end side to the other end side of the scan electrodes CL. A signal voltage correction unit that corrects the signal voltage is provided so that the predetermined voltage applied to the signal electrodes SL1 to SLM increases stepwise. The signal voltage correction means includes a supply line for the bias voltages V1 and V0 and the signal drive IC 7 so that the voltage supplied to the signal drive IC 7, for example, the bias voltages V1 and V0 are sequentially changed depending on the position of the signal drive IC. Voltage correction circuit 8 connected between
Is used. In this example, as the voltage correction circuit 8, resistors R1 to R8 corresponding to each signal drive IC 7 are used. Here, the values of the resistors R1 to R8 are R1>R2> ...
>R7> R8, and is set so that a substantially constant voltage can be obtained in the cell defined by the predetermined scan electrode CL and the signal electrodes SL1 to SLM intersecting with the predetermined scan electrode CL.

In the example of voltage correction by the resistance R, the unit of the signal electrode SL for which the applied voltage is corrected is not one unit, but the number of signal electrodes SL connected to the signal driving IC 7, that is, a unit of a plurality of electrodes. However, since the value of the resistor R may be set for each signal drive IC 7, the configuration can be simplified. Instead of attaching the resistor R externally, the signal driving IC 7 can be used as a configuration including a variable resistance circuit having the same function as the resistors R1 to R8. Further, the signal voltage correction means is the resistor R
The configuration is not limited to 1 to R8, and other configurations can be adopted.

As described above, in consideration of the resistance increase along the extension direction of the scan electrode CL, the predetermined voltage (bias voltage V1, V0, etc.) applied to the signal electrode SL is applied from one end side to the other end of the scan electrode CL. Since the voltage increases stepwise in the direction toward the side, the voltage applied to a cell defined by one scan electrode CL and a plurality of signal electrodes SL1 to SLM intersecting with it, that is, a cell arranged in the same direction as the scan electrode CL. Can be kept substantially the same, and the occurrence of crosstalk level difference can be suppressed.

[0011]

As described above, according to the present invention, since the means for correcting the voltage applied to the signal electrode along the extension direction of the scan electrode is provided, the voltage applied to the cell in the same direction as the scan electrode is almost equal. It can be kept constant, and even if the display screen becomes large, it is possible to suppress the occurrence of a crosstalk level difference in the scanning electrode direction and maintain good display quality.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 1st board 3 2nd board 4 Scanning circuit 5 Scanning drive IC 6 Signal circuit 7 Signal drive IC 8 Voltage correction circuit CL Scan electrode SL Signal electrode

Claims (1)

[Claims] 1. A liquid crystal panel in which a substrate having a plurality of scanning electrodes and a substrate having a plurality of signal electrodes are arranged to face each other with a liquid crystal layer interposed so that the scanning electrodes and the signal electrodes intersect each other.
A scanning circuit for applying a scanning voltage to one end of the scanning electrode;
A liquid crystal display device having a signal circuit for applying a signal voltage to the signal electrode and applying a desired voltage to a cell defined by an intersection of the scanning electrode and the signal electrode, wherein one end of the scanning electrode to the other end thereof. A liquid crystal display device, comprising: a signal voltage correction unit that corrects the signal voltage so that the voltage applied to the signal electrode gradually increases toward the side.