JPH09101497A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To display a color moving picture by using a TN mode type liquid crystal display element. SOLUTION: This device consists of a TN mode type liquid crystal display 1, a back light 2 consisting of three color tubes of R, G, and B, and a driving circuit which controls the liquid crystal display 1 and back light 2. For every video composite frame the tubes 22, 23, and 24 of R, G, and B of the back light 2 is turned on in order at the same period and a liquid crystal display element 13 at a specific dot position of the liquid crystal display 1 is driven corresponding to the illumination period of the tubes 22, 23, and 24 of R, G, and B so that the quantity of integration for variation of the liquid crystal display element 14 by repetitive voltage application is adjusted.

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, and more particularly to a color display liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, there has been known a liquid crystal display device for color display by a color filter using a TFT and a TN mode liquid crystal display element.

Among them, the color display liquid crystal display device using the TN mode type liquid crystal display element has a simple structure because it is driven by a simple matrix, and is easy to manufacture and can be manufactured at a low cost. .

[0004]

However, the simple matrix driving method is a method in which the liquid crystal of each pixel arranged in the matrix is directly driven from the outside in synchronization with a scanning signal. The drive time (duty) assigned to the display is reduced, and as a result, the display contrast ratio is reduced.

In the color display, this decrease in contrast is reflected in the vividness of the color, so that sufficient color display cannot be performed.

[0006] Therefore, by using an active element including a transistor and a diode, a static characteristic is reproduced regardless of a driving time (duty) assigned to one pixel, and an active matrix driven liquid crystal capable of reproducing a high quality color screen. Although a display device is used, on the other hand, there is a problem that the structure is complicated, the manufacturing is difficult, the yield is low, and the manufacturing cost is high.

The present invention has been made in view of the above problems, and the problem to be solved by the present invention is that a liquid crystal display suitable for a color moving picture image has a fast frame response speed and a good contrast ratio. The device is provided easily and inexpensively.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and includes a TN mode type liquid crystal display, a backlight composed of R, G and B tricolor tubes, and the liquid crystal. A display circuit for controlling the display and the backlight is provided, and the R, G, B tubes of the backlight are sequentially turned on at equal intervals for each video color composition frame, and the R, G, B tubes are It is characterized in that the liquid crystal display element at a predetermined dot position in the liquid crystal display is driven so as to adjust the amount of integration with respect to changes in the liquid crystal display element by applying a high-speed repetitive voltage in correspondence with the lighting cycle.

[0009]

Next, an embodiment of the present invention will be described.

The drawings show a preferred embodiment of the liquid crystal display device according to the present invention. As shown in FIG.
It comprises a mode-type liquid crystal display 1, a backlight 2 composed of R, G, B tricolor tubes, and a drive circuit (not shown) for controlling these liquid crystal display 1 and backlight 2.

Further, as the TN mode type liquid crystal display display 1, it is possible to use the same one as the transmission type TN mode type liquid crystal display display which has been generally manufactured in the past, as it is. , A glass substrate 12, an electronic circuit 13, a liquid crystal display element 14, and a surface cover 15 are sequentially laminated.

The backlight 2 is a light guide plate 2 disposed under the polarizing plate 11 in the liquid crystal display 1.
1 and an R (red) tube 22 arranged on one side of this,
It is composed of a G (green) tube 23 and a B (blue) tube 24.

Then, as shown in FIG. 2, the R, G, and B tubes 22 of the backlight are provided for each video color composition frame (for example, a cycle of about 40 Hz) by a drive circuit (not shown).
23, 24 are sequentially lit at an equal cycle (for example, a cycle of about 120 Hz), and R, G, B tubes 22, 23,
An arbitrary color display is obtained by a visual afterimage phenomenon that occurs when the TN mode type liquid crystal display element 14 at a predetermined dot position is turned on and off in correspondence with the lighting cycle (color frame) of 24.

In particular, in the embodiment of the present invention, the liquid crystal display element 14 is driven so as to adjust the amount of integration with respect to changes in the liquid crystal display element by repeatedly applying a voltage (for example, a cycle of about 40 KHz). .

Next, an actual timing chart in the present embodiment is shown in FIG.

In the timing chart shown in FIG. 3, any gradation can be set between 1 and 256 sheets,
As shown in FIG. 4, the display gradation is integrated by changing the liquid crystal display element by giving a gradation number to the image information and performing a display operation by the number of gradation times times the number of repetitions in the minimum gradation. Can be adjusted in stages to adjust the amount of change.

When the voltage is repeatedly applied, the time interval between the ON signal and the OFF signal cycles with respect to the dot position of the liquid crystal display element 11 is shortened, and the integration / differentiation operation in the ON / OFF operation of the liquid crystal display element is considered. The on-operation (integration operation) excellent in operation response is displayed many times in a short time, and the R, G, and B tubes 22, 2 are integrated.
The operation speed of the liquid crystal display element that can correspond to the display information that changes every lighting cycle (color frame) of 3, 24 is obtained.

Further, in order to prevent the colors from being mixed when the liquid crystal display element 11 is switched from ON to OFF, the R, G and B tubes 22, 23 and 24 are provided between the sub-frames.
It is advisable to provide a time during which neither of these lights up.

[0019]

As described above, according to the present invention, even if an STN type liquid crystal display device by a simple matrix driving method, which has a simple structure, is easy to manufacture and can be manufactured at a low price, is sufficiently colored. It can be displayed.

In particular, compared with a conventional color liquid crystal display device using an additive color mixture using a color filter, it is possible to obtain a high resolution without the need for a color filter, and a small number of drive ICs is required. It is very easy to adjust the color balance by using the light source independent of each color.

Furthermore, since STN type liquid crystal display elements, which have been conventionally produced in large quantities, are used as the liquid crystal display, production is possible without changing the factory line, which is extremely economically advantageous.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the principle of color display in the present invention.

3 is a preferred timing chart in the embodiment shown in FIG.

FIG. 4 is an explanatory diagram showing an adjustment state of display gradation in the timing chart shown in FIG.

[Explanation of symbols]

 1 LCD display 2 Backlight 22 R tube 23 G tube 24 B tube

Claims (1)

[Claims] 1. A TN mode type liquid crystal display, a backlight composed of R, G and B tricolor tubes, and a drive circuit for controlling the liquid crystal display and the backlight. The R, G, and B tubes of the backlight are sequentially turned on at regular intervals, and
A liquid crystal display element at a predetermined dot position in the liquid crystal display in correspondence with the lighting cycle of each of the R, G and B tubes,
A liquid crystal display device characterized in that the liquid crystal display device is driven so as to adjust the amount of integration with respect to changes in the liquid crystal display device by repeatedly applying voltage.