Automatic contrast adjusting circuit

Abstract

An automatic contrast adjusting circuit comprises a grid driver scan driver (SD), a source driver data driver (DD), a direct current power supply converter direct current (DC) / DC, a time schedule controller (TCON) and a contrast voltage generating circuit. Power is supplied in DC / DC mode, a relevant control signal output end of the TCON is respectively connected with driving control signal input ends of the SD and the DD, and the contrast voltage generating circuit outputs contrast voltage to a corresponding input end of the DD and corresponding sources and grids of all pixels in an output driving liquid crystal panel of the SD and the DD. Virtual pixels of a liquid crystal panel to be adjusted feeds back drain voltage of the panel to the input end of the contrast voltage generating circuit, and contrast voltage is generated in the contrast voltage generating circuit and output to a corresponding contrast voltage input end of the DD. The automatic contrast adjusting circuit can be applied to reducing of Flicker and automatic adjustment of Gamma. Problems of contrast curve deflection, brightness separation and Flicker due to offset of manufacture procedure conditions are solved in automatic compensation method.

Description

technical field [0001] The invention relates to a TFT liquid crystal display, in particular to a gradation voltage adjustment circuit of the display, in particular to an automatic gradation adjustment circuit. Background technique [0002] In the TFT liquid crystal display, the traditional step voltage adjustment method needs to be manually adjusted by the designer. Under the traditional circuit structure, the step voltage generation circuit generates V1 ~ Vn through resistor divider and operational amplifier. Dummy pixels on the panel are not used for calculations, and their disadvantages are: [0003] 1. The delta Vp (kickback voltage) value of each step cannot be accurately obtained [0004] 2. The gradation voltage is a fixed value, once determined, it cannot be changed easily. [0005] 3. When the panel process conditions change, the step voltage must be readjusted. [0006] 4. The tone adjustment process is cumbersome, labor-intensive and time-consuming. [0007] W...

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to propose an automatic tone adjustment circuit for the problems of low adjustment accuracy, cumbersome process, laborious and time-consuming, and increased production costs in the traditional method of adjusting voltage adjustment by the designer.

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