JPH0132995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive circuit for a liquid crystal display device that performs color display.

A drive circuit for a liquid crystal display device using a conventional active matrix substrate is shown in FIGS. 1 and 2.

FIG. 1 is a circuit diagram of an active matrix panel and peripheral drive circuit. 101 in Figure 1
102 is an active matrix panel, 103 is a gate line side driving circuit, 104 is a shift register, 105 is a clock input terminal, 106 is a sample data input terminal,
107 is a video input terminal, 108 is a MOS transistor, 109 is a pixel, 110 is a shift register, 111 is a scan data input terminal, 112 is a clock input terminal, 113 is a MOS transistor,
114 is a capacitor, 115 is a liquid crystal, and 116 is a common electrode.

FIG. 2 is a block diagram of a video signal processing circuit. In Fig. 2, 201 is a video input terminal;
02 is a preamplifier, 203 is a complementary polarity video signal generator, 204 is a frame changeover switch, 205
is a frame input terminal, 206 is a buffer amplifier,
207 is a video output terminal.

Conventional liquid crystal display devices provide monochrome display. Currently, a method of providing a color filter for each pixel has been devised as a color display method. However, in conventional drive circuits for liquid crystal display devices, independent primary color signals cannot be applied to each pixel.
There is only one video signal processing system. Therefore, it is unsuitable as a drive circuit for color display.
There were drawbacks as mentioned above.

The present invention eliminates such drawbacks, and its purpose is to provide a drive circuit most suitable for a liquid crystal display device that performs color display using an active matrix substrate. The present invention will be described in detail below based on Examples.

FIG. 3 is a circuit diagram of the active matrix panel and peripheral drive circuit of the liquid crystal display device of the present invention.
In FIG. 3, 301 is a source line side drive circuit, 302 is an active matrix panel, and 30
3 is a gate line side drive circuit, 304 is a shift register, 305 is a clock input terminal, 306 is a sample data input terminal, 307 is a primary color signal input terminal, 308 is a MOS transistor, 309 is a pixel,
310 is a shift register, 311 is a scan data input terminal, 312 is a clock input terminal, 313
is a MOS transistor, 314 is a capacitor, 3
15 is a liquid crystal, and 316 is a common electrode. As is clear from FIG. 3, the present invention has a plurality of primary color signal input terminals, and each primary color signal is applied separately. This is to improve the degree of separation of each primary color signal, and is because if an attempt was made to add them through a common input line, crosstalk would occur between each primary color signal due to the high sampling frequency.

The present invention will be described based on an example in which each pixel is provided with a mosaic color filter. FIG. 4 shows an example of the color filter arrangement, in which the color filter arrangement is shifted line by line. In FIG. 4, R is a red filter, G is a green filter, and B is a blue filter, which performs full color display using the additive color method.

FIG. 5 is a block diagram of a color signal processing circuit when the color filter arrangement shown in FIG. 4 is used.

Color difference signal R-S goes to terminal 501, color difference signal G-
Y goes to terminal 502, color difference signal BY goes to terminal 503
, the luminance signal Y is input to the terminal 504. These color difference signals are processed by primary color signal regenerators 511, 512,
At step 513, the primary color signals R, G, and B are reproduced. 514 is a luminance signal buffer. Reproduction primary color signal R, G, B signal selection switches 701, 70
2,703, respectively. This R, G,
The switching timing of the B signal selection switch is determined by the frame synchronization signal input to the terminal 704. These selected R, G, B primary color signals are transmitted to complementary primary color signal generators 521, 522, 52.
3. This complementary primary color signal generator 52
1,522,523 is positive polarity and negative polarity R,
Generates G and B primary color signals. Among these complementary polarity primary color signals, the unipolar signal is selected for each frame by frame selection switches 531, 532, and 533. Frame selection switch 531, 53
2,533 is controlled by a frame signal input to a terminal 534. These selected unipolar signals are amplified by buffers 541, 542, 543 and taken out to output terminals 711, 712, 713.

Here, if the output terminal 711 is connected to the primary color signal input terminals connected to the first, fourth, and seventh primary color signal input terminals from the left in FIG. The R, G, B signal changeover switch of 701 is connected to terminal 7 so that the primary color signal is output, the second signal is the blue primary color signal, and the third signal is the green primary color signal.
Controlled by 04. 702,703 R, G, B
The same applies to the signal changeover switch.

FIG. 6 is a circuit block diagram in which the R, G, B signal changeover switches 701, 702, 703 of FIG. 5 are arranged after the frame selection switches 531, 532, 533. Other than this point, there is no difference from the configuration shown in FIG. 5.

The present invention provides an optimal drive circuit for a liquid crystal display device that performs color display using an active matrix substrate, and its features are as follows. Since the primary color signals (red, blue, and green) are applied to separate common lines (source-side drive circuits around the panel), there is no crosstalk or deviation of each color due to sample-hold deviation, and color reproducibility is good. Fourth
In addition to the ones shown in the figure, it is possible to accommodate various color pixel arrays such as color filters. The color signal processing circuit has a simple circuit and drives a capacitive load, and its power is low.
Compatible with the low power of LCD. Easy to interface with conventional color TV demodulation circuits.

The present invention is particularly effective when a color television is constructed using liquid crystal using an active matrix substrate together with a color filter.

As described above, the present invention includes pixel electrodes in which an electro-optic conversion substance is sealed within a pair of substrates, arranged in a matrix on the substrates, and arranged in a mosaic pattern corresponding to each of the pixel electrodes. In a display device having a three primary color filter, a first primary color signal selection means selects one of the three primary color signals, a second primary color signal selects a second primary color signal of the three primary color signals. a selection means, a third primary color signal selection means for selecting three primary color signals from the three primary color signals, a first transmission circuit for transmitting the primary color signal from the first primary color signal selection means, and a primary color from the second signal selection means. a second transmission circuit for transmitting the signal; a third transmission circuit for transmitting the primary color signal from the third signal selection means; sampling the three primary color signals from the first, second, and third transmission circuits using a clock signal; It has a plurality of primary color signal sampling means for supplying to the pixel electrodes, and the primary color signal selection timing of the first primary color signal selection means, the second primary color selection means, and the third primary color selection means is determined based on the timing of the primary color signal selection of the pixel electrodes arranged in a matrix. Since this is done in synchronization with each row switching, even if color filters arranged in a matrix are arranged in a mosaic arrangement, accurate primary color signals can be supplied to the pixel electrodes at positions corresponding to such a mosaic arrangement. . Furthermore, since the selection timing of the primary color signal is synchronized with the switching of each row of pixels, there is no need to select colors using a high frequency, and a signal synchronized with the scanning signal of the television signal can be used.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a conventional active matrix panel and peripheral drive circuit. FIG. 2 is a block diagram of a conventional video signal processing circuit. FIG. 3 is a circuit diagram of the active matrix panel and peripheral drive circuit of the present invention. FIG. 4 is an arrangement diagram of color filters according to an embodiment of the present invention. Fifth
The figure is a block diagram of a first embodiment of the color signal processing circuit of the present invention. FIG. 6 is a block diagram of a second embodiment of the color signal processing circuit of the present invention. 101... Source line side drive circuit, 102... Active matrix panel, 103... Gate line side drive circuit, 104... Shift register, 105
...Clock input terminal, 106...Sample data input terminal, 107...Video input terminal, 511, 51
2,513...Primary color signal regenerator, 521,522,
523... Complementary polarity primary color signal generator, 531, 53
2,533...Frame selection switch, 701,7
02,703...R, G, B signal changeover switch, 7
11, 712, 713...output terminals.

Claims (1)

[Claims] 1. An electro-optical conversion substance is sealed in a pair of substrates, pixel electrodes are arranged in a matrix on the substrates, and three primary color filters are arranged in a mosaic pattern and correspond to each of the pixel electrodes. A display device comprising a first primary color signal selection means for selecting one of the three primary color signals, a second primary color signal selection means for selecting two of the three primary color signals, and the three primary color signals. a third primary color signal selection means for selecting three primary color signals among the three primary color signals; a first transmission circuit for transmitting the primary color signal from the first primary color signal selection means; and a second transmission circuit for transmitting the primary color signal from the second signal selection means. a transmission circuit, a third transmission circuit for transmitting the primary color signal from the third signal selection means, a plurality of sampling circuits for sampling the three primary color signals from the first, second and third transmission circuits using a clock signal and supplying the samples to the pixel electrodes; primary color signal sampling means, and the primary color signal selection timing of the first primary color signal selection means, the second primary color selection means, and the third primary color selection means is synchronized with switching of each row of the pixel electrodes arranged in a matrix. A display device.