Research On LCD Color Demura Method

The liquid crystal display industry is a strategic high-tech industry that is developed by the state.LCD is now the mainstream display device and is widely used in various fields.Under current production technology conditions,LCD products produced by the factory have a display defect(Mura),which affects the display quality.The flat panel display industry called the method of eliminating Mura as Demura.The use of Demura system equipment can improve the display quality of products and thus enhance the competitiveness of products.The existing Demura system equipment in China has problems such as slow running speed and poor display correction effect,which is difficult to meet current production requirements.This article studies the related methods of displaying uniformity correction,and solves the above problems by designing and implementing Demura system.The main work of the thesis is as follows:1)A method for correcting LCD brightness uniformity based on polynomial-gamma segmented electro-optic response model is proposed.The method uses polynomial and gamma functions to respectively represent the electro-optical response model of LCD with low brightness and high brightness.The LCD displays the brightness sample data collected by the CCD camera to estimate the parameters of the electro-optical response model,and the estimated model parameters are used to realize Brightness uniformity correction.The model can accurately estimate the response model of the LCD with a small amount of sample data,reducing the correction time.It is concluded from the experiment that the method solves the problem that the correction effect of the low-brightness display signal area of the LCD is not good,and the correction effect reaches the requirement of the brightness uniformity correction industrial technical index of the display.2)Based on the brightness uniformity correction,a chromaticity uniformity correction method based on Taylor series expansion model is proposed.The Taylor series expansion is used to establish the response model of the local LCD color change,which reduces the difficulty of establishing the color response model.The CCD color camera is used to measure the display sample data to estimate the model parameters,and the estimated model parameters are used to implement the chromaticity uniformity correction.It is concluded from the experiment that the method of this paper can effectively solve the problem of unevenness in chromaticity display,and the correction effect meets the requirements of general industrial indicators.3)Based on the correction method of luminance and chrominance uniformity,the GPU color parallel camera-based Color Demura system is designed and implemented by using GPU general parallel computing method.Install the designed system on the purchased hardware equipment,build a complete set of Color Demura system equipment,and test the performance of the system in the factory.The results show that the design system of this paper runs fast and meets the relevant technical requirements of LCD industrial production.In summary,the brightness chromaticity uniformity correction method developed in this paper can effectively solve the problem of LCD display unevenness,and the system designed and implemented can meet the current LCD production requirements.