JPS6214625A - Driving method for liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve color reproducibility and contrast by making different effective value voltages for selection and nonselection applied to the liquid crystal layer of each picture element. CONSTITUTION:A row driver 4 selects scanning electrodes 1 in order and a column driver 5 outputs data corresponding to the respective scanning electrodes in synchronism with the row driver 4. At this time, the output signal of the column driver 5 is voltage-divided by a voltage dividing resistance 3. Therefore, the voltage-division ratio of this voltage dividing resistance is set to values which are different among respective signal electrodes of red, green, and blue, thereby making effective value voltages which are applied to picture elements of red, green, and blue different from one another. Then, the effective value voltages applied to the picture elements of red, green, and blue are set so that three curves of relative transmissivity-voltage characteristics coincide with one another. Consequently, the adverse influence of rotary polarization dispersion such as a decrease in contrast and deterioration in color reproducibility is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for driving a liquid crystal display device for video and information equipment, and more particularly to a method for driving a full-color display device using liquid crystal.

2. Description of the Related Art In recent years, there has been an increasing demand for large-screen, thin, full-color display devices in the field of information equipment, mainly computers, and in the field of video equipment, mainly televisions, VTRs, and the like. As a display device of this type, there is a liquid crystal display device that provides a red, green, and blue color filter for each pixel, uses a liquid crystal as a shutter, controls transmitted light, and displays full color by additive color mixing. (For example, Nikkei Electronics, 1
September 10, 984, P211-P240. ``Commercialized LCD pocket color television''. ) Problems to be Solved by the Invention However, in the color liquid crystal display device having the above-mentioned configuration, there is a phenomenon peculiar to the currently widely used twisted nematic type liquid crystal display panel, which is that the color liquid crystal display device has problems due to the wavelengths of red, green, and blue. Optical rotation dispersion becomes a problem. This optical rotation dispersion is
The optical rotation power when a voltage is applied to a liquid crystal varies depending on the wavelength of the light that passes through the liquid crystal.For this reason, when using a polarizing plate as a shutter, the transmittance of light varies depending on the wavelength, resulting in However, there were problems in that color reproducibility and contrast deteriorated.

Therefore, the present invention provides an effective driving method for improving color reproducibility and contrast in such a color liquid crystal display device.

Means for Solving the Problems The technical means of the present invention for solving the above problems is to set the selection and non-selection effective value voltages applied to the liquid crystal layer of each pixel to be different for each color pixel. It is something to tighten.

For production The effect of this technical means is as follows.

That is, in the present invention, the transmittance is compensated for by changing the voltage applied to each color pixel by the difference in transmittance of each color due to optical rotation dispersion.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 2 is a graph showing the relationship between the voltage applied to the liquid crystal layer and the relative transmittance of the liquid crystal layer. In Figure 2, 6, 7
．． 8 indicates the relative transmittance of each color of red, green, and blue, respectively,
Due to optical rotation dispersion, the transmittance of each color differs for the same applied voltage.

Therefore, by changing the effective value voltage applied to each color so that the transmittance of each color is equal, the transmittance can be made almost equal.

FIG. 1 is a configuration diagram of a liquid crystal display device showing one embodiment of the present invention. In FIG. 1, 1 is a scanning electrode, 2a is a red signal electrode, 2b is a green signal electrode, 2C is a blue signal electrode, 3 is a voltage dividing resistor, 4 is a row driver, and 5 is a column driver.

The operation of the liquid crystal display device of the present invention configured as above will be explained. In FIG. 1, the row driver 4 is the scanning electrode 1.
are sequentially selected, and the column driver 6 outputs data corresponding to each scan electrode in synchronization with the row driver 4. At this time, the output signal of the column driver 5 is voltage-divided by the voltage-dividing resistor 3. Therefore, the voltage dividing ratio of this voltage dividing resistor 3 is set to red, green,
By setting different values for each signal electrode on the back,
The effective value voltage applied to each red, green, and blue pixel can be made different. Then, the effective value voltages applied to each red, green, and blue pixel are adjusted so that the three curves 6.7.8 of the 1 vs. transmittance-voltage characteristic shown in Figure 2 match. By setting this, it is possible to reduce adverse effects such as a decrease in contrast and deterioration in color reproducibility due to optical rotation dispersion.

The structure of the liquid crystal panel shown in FIG. 1 is a 10×9 matrix panel for ease of understanding, but the structure is not limited to this. Furthermore, although the voltage applied to the signal electrodes is divided by the resistors, it is not limited to this, and it is sufficient that the effective value voltage of selection and non-selection applied to each pixel of each color is different. Needless to say.

Effects of the Invention The present invention is a liquid crystal color display device composed of a scanning electrode and a signal electrode, in which the selection and non-selection effective value voltages applied to each pixel of each color are driven differently for each pixel of each color. By doing so, it is possible to reduce the adverse effects of a decrease in contrast and deterioration in color reproducibility due to optical rotation dispersion.

[Brief explanation of drawings]

FIG. 2 is a block diagram for realizing a driving method of a liquid crystal display device according to an embodiment of the invention; FIG. 2 is a relative transmittance-applied voltage characteristic diagram due to optical rotational dispersion of the liquid crystal display device; Na≠≠palm. 1...Scanning electrode, 2a...Red signal electrode, 2b...Green signal electrode, 2c...Blue signal electrode, 3...Minute Piezoresistor, 4...Row driver, 5...Column driver.

Claims (2)

[Claims] (1) A method for driving a liquid crystal display device having a scanning electrode group and a signal electrode group, each pixel being constituted by the scanning electrode and the signal electrode, and each pixel including at least two color pixels. 1. A method for driving a liquid crystal display device, characterized in that effective value voltages for selection and non-selection applied to a liquid crystal layer of each pixel of each color are made different for each pixel of at least two colors. (2) A liquid crystal display according to claim (1), characterized in that a higher effective value voltage is applied to color pixels containing short wavelength components than to color pixels containing long wavelength components. How to drive the device.