System Design And Implementation Of Multi-Point Flicker And γ Curve Correction For Lcd Screen

With the rapid development of smart phones,the liquid crystal display technology has also made great progress.As consumers use more and more display products,they understand more and more deeply,and the demand for display effect is also higher and higher.In the current LCD evaluation standards,the consistency control of LCD Flicker and γ curve are two important evaluation standards.According to current industry standards,the Flicker of LCD should be less than-30 dB in the center point.The γ curve requires that the shape of the curve is as smooth as possible.The γcurve is normally controlled from γ1.9 to γ2.5 according to the current industry standards.This thesis aims to study a correction method for testing and correcting the LCD multi-point Flicker.The correction can make the multi-point Flicker less than-25 dB and the center point Flicker less than-30 dB.The correction can improve the Flicker of the screen.According to design the correction method for γcurve,the γ curve can be improved to further narrow tolerances of γ2.2±0.2,and the tolerance of color coordinates of white picture is reduced to 0.01.The above correction method needs to meet the on-line calibration of mass production,and can correct each product in production.This thesis introduces the main driving principles of LCD and describes the basic reason of Flicker.For these reasons,we put forward the improvement direction of the basic research.In this thesis,the measuring method and calculation method of Flicker are studied,and a correction platform which can measure and correct the multi-point Flicker level of the LCD is designed.This thesis shows that the cause of the γ curve is because the recognition of the human eye is nonlinear.By analyzing and studying the causes of the γ curve,this thesis studied the correction method of controlling the curve in the range ofγ2.2±0.2,which can meet the online automatic correction and ensure the correction and control of the γ curve characteristics in mass production.It's considered that the main reason for the white spot color difference is that the thickness of LCD color filter film is hard to control accurately,and the color difference of LED is difficult to control in a smaller range.The above reasons will lead to the larger color difference between different screens,and the consistency of the white picture coordinates is more difficult to control.Based on the abovesituation,we hope to study a calibration device online measuring and calculating the optical parameters of the screen,and adjust the color coordinates of the white picture by adjusting the three γ curve.Based on the research of white balance,γ curve and Flicker correction method,an on-line testing and correction equipment is designed.According to the final test results,the correction can make the multi-point Flicker less than-25 dB and the center point Flicker less than-30 dB;γ curve can be controlled in the range ofγ2.2±0.2;white screen color coordinate tolerance can be controlled within 0.01 range,realize the batch case showed improvement and consistency control.