Research Of LTPS-LCD Image Display Rapid Correction System Based On Android Platform

LTPS-LCD(Low Temperature Poly-silicon Liquid Crystal Display)has become the mainstream display devices of High-end mobile phones,tablet computers and other small/medium-size terminals because of its high penetration rate,high resolution and low power consumption.In spite of the fast development of LTPS-LCD,the products have low stabilities and obvious differeces between pieces causing by high integration,plenty procedures and complex processes;therefore,yields and shipments of LTPS-LCD products are seriously affected.To assure the high performance of LTPS-LCD,it is necsssary for every LTPS-LCD to be corrected,including flicker correction,gray-scale brightness correction,chromaticity correction(Gamma and color temperature correction)and so on.The existing automatic correction systems are time-consuming,costly,bulky and inconvenient;thus,they cannot meet the requirements of LTPS-LCD products correction.Aiming at these-existing problems and combining with the demands of enterprise,this paper designed an automatic correction system of LTPS-LCD image display and proposed the fast correction algorithms.According to the analysis of the effects of driving circuits on the display performance of LTPS-LCD,correction algorithms of flicker,gray-scale brightness,chromaticity and image sticking are designed.For flicker correction,frequency domain-based JEITA is used for measurement.Dichotomy and symmetric methods are used to achieve fast corrections.For gray-scale brightness and chromaticity correction,Grsassmann color law and cubic spline interpolation with natural boundary condition are used to obtain the transmittances of RGB channels promptly and then realizes the fast corrections.For image sticking correction,fitting of a polynomial is used to get the best Vcom of different gray-scale voltages precisely,and then the corrections are accomplished combining with the asymmetric Gamma.Automatic correction system consists of hardware and software.For hardware,system considers Exynos4412 as its center controller and designs RGB and MIPI interfaces for LTPS-LCDs.Besides,the communication interfaces and power modules are designed and implemented.System selects fast-speed Admesy MSE as LTPS-LCD measurement device and uses four-color matrix correction method to calibrate the MSE accurately.For software,system chooses open-source and interactive Android as operating system and then implements the application software and driver software respectively.Driver software includes the realizations of LTPS-LCD driver and USB mouse driver.Application software includes the design of operation interface and program implementations of correction algorithm.Besides,JNI interface is designed to achieve the communication and operation between application software and bottom devices.Finally,the correction system is tested and results of LTPS-LCDs are analyzed.Test results show that correction system can achieve fast and accurate corrections for LTPS-LCDs' flicker,gray-scale brightness,chromaticity and image sticking.The flicker correction takes within 3s,gray-scale brightness and chromaticity correction takes within 10s and image sticking correction takes within 1min.After correction,problems of flicker and image sticking will be solved,accuracy rate of gray-scale brightness is within 1%,error range of gray-scale chromaticity is within ±0.002(CIE1931-xy).It can be concluded that performances of image display are significcantly improved.