JPH02271389A - Full color LCD display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention sequentially supplies red gradation data, green gradation data, and blue gradation data to a driver in accordance with the pixel arrangement of a color liquid crystal panel. The present invention relates to a full-color liquid crystal display device that obtains color images.

"Conventional technology" A conventional full-color liquid crystal display device is shown in FIG.

The color television signal selected by the tuner 11 is supplied as an intermediate frequency signal to an IF amplified video detection circuit 12, where the intermediate frequency is amplified and then video detected. The detected output is demodulated by the chroma demodulation circuit 13 into red gradation data R1, green gradation data G1, and blue gradation data B, and is supplied to the RGB switching circuit 14. IF amplified video detection circuit 1
A synchronization signal is selected by the synchronization control circuit 15 from the detection output of No. 2, and the RGB switching circuit 14 is controlled by the synchronization control circuit 15, and the red gradation data, green gradation data, and blue gradation data are colored. The signals are sequentially taken out in the order of pixel arrangement of the liquid crystal panel 16 and supplied to the X driver 17 of the color liquid crystal panel 16. A Y driver 18 consisting of a shift register is controlled by a horizontal synchronization signal from a synchronization control circuit 15, and the color liquid crystal panel 16 is driven line-sequentially to obtain a color image.

"Problem to be solved by the invention" Color liquid crystal panel 16 composed of red, green, and blue pixels
When performing full-color display, do you need to control the voltage applied to each pixel? However, as shown in Figure 6, the relationship between the applied voltage and the liquid crystal brightness is non-linear, and the characteristic curve changes depending on red (R), green (G), and blue (B). It's different.

Therefore, in the conventional full-color liquid crystal display device, in which the demodulated gradation data of each color is amplified using an analog system to obtain the voltage applied to the liquid crystal, there is no color shift, that is, red, green,
It has been difficult to correct so that the blue luminance ratio is constant and the liquid crystal luminance-gradation data characteristics are linear.

An object of the present invention is to provide a full-color liquid crystal display device that realizes linear liquid crystal brightness-gradation data characteristics without color shift and can display full-color images with excellent display quality.

"One step to solving the problem" According to this invention, digital color gradation data is input, the voltage correction table for red pixels is read out using the red gradation data, and the red pixel voltage correction table is read out using the red gradation data, and The pixel voltage correction table is read out, and the blue pixel voltage correction table is read out using the blue gradation data.The data read out from these voltage correction tables are converted into analog signals by the D/A converter and color Supplied to the LCD panel driver. Each voltage correction table corrects the gradation data so that the liquid crystal brightness-gradation data characteristic of the color liquid crystal panel becomes linear.

Embodiment FIG. 1 shows an embodiment of the present invention. Digital color gradation data is generated by the CPU 21, and the data is stored in the video RAM 22. The video RAM 22 is controlled by the display control circuit 23, and red gradation data, green gradation data, and blue gradation data are sequentially read out in the order of pixel arrangement of the color liquid crystal panel 1G.

The gradation data read from the video RAM 22 is, for example, 4 bits, and is supplied to the voltage correction table 24 as addresses Δ0 to A3. R indicating whether the gradation data supplied to the voltage correction table 24 is red, green, or blue.
The GI3 code is sent from the display control circuit 23 to addresses A4 and A.
5 and is supplied to the voltage correction table 24. The data read out from the voltage correction table 24 is, for example, 8 bits, and the gradation data is corrected so that the liquid crystal brightness-gradation data characteristic becomes linear.
/A converter 25 converts the signal into an analog signal and supplies it to X driver 17.

An example of the configuration of the voltage correction table 24 is shown in FIG.

A table for red pixels, a table for recording water, and a table for blue pixels are provided, and one of these tables has RGB code A.
4, A5 is selected, and the selected table is read out using the gradation data AO-A3 supplied at that time. The correction data in each table is determined so that the liquid crystal luminance-gradation data characteristic becomes linear as shown in FIG.

An example in which the present invention is applied to a device that displays analog color television signals in color is shown in FIG. 4, in which the same reference numerals are given to the parts corresponding to those in FIG. Serial data of green gradation data and blue gradation data are converted into 4 pieces each by the A/D converter 26.
It is converted into bit digital gradation data, and the digital gradation data is supplied to the voltage correction table 24 as an address. The voltage correction table 24 includes a synchronous control circuit 15.
The RGB code is supplied as an address. The corrected data from the voltage correction table 24 is converted into an analog signal by the D/A converter 25 and sent to the X driver 1.
7.

"Effects of the Invention" As described above, according to the present invention, by providing a voltage correction table, linear gradation display without color shift can be realized.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of the contents of the voltage correction table 24, FIG. 3 is a diagram showing liquid crystal brightness-gradation data characteristics of the device of this invention, and FIG. FIG. 5 is a block diagram showing another embodiment of the present invention, FIG. 5 is a block diagram showing a conventional full-color liquid crystal display device, and FIG. 6 is a diagram showing liquid crystal brightness-applied voltage characteristics of a color liquid crystal panel.

Claims (1)

[Claims] (1) In a full-color liquid crystal display device that obtains a color image by sequentially supplying red gradation data, green gradation data, and blue gradation data to a driver in accordance with the pixel arrangement of the color liquid crystal panel, digital Color gradation data is input, and a red pixel voltage correction table is read out using the red gradation data, a green pixel voltage correction table is read out using the green gradation data, and a blue voltage correction table is read out using the blue gradation data. It has pixel voltage correction tables, and a D/A converter that converts data read from these voltage correction tables into analog signals and supplies them to the driver, and each of the voltage correction tables is connected to the liquid crystal of the color liquid crystal panel. A full-color liquid crystal display device that corrects gradation data so that the luminance-gradation data characteristics are linear.