Investigation On Spectral Optimization Of High Color Gamut Liquid Crystal Display

Liquid crystal display(LCD)is widely used because of its lightweight,environmentally friendly and perfect performance.Whether it is small and medium size smartphone,tablet,or large-size notebook computers,televisions,liquid crystal display is the mainstream.But compare with the organic light emitting display(OLED)that rise in recent years,its color performance is not satisfactory.Therefore,we try to enhance the color performance of LCD by using color filters and backlight,and even the optimization match between them.So the investigations of this article are as follows:Firstly,the influence of RGB resist thickness on LCD color gamut has been researched.The RGB resists with different thickness are prepared by roll coating printed method base on glare glass,and then the spectrums of different thickness are collected.To analyze the influence of RGB resist thickness on color gamut,the simulation results of LCD module with different thickness are made by homemade color simulator,and the simulation results are verified by experiment.The results show that the color gamut will be enhanced by increasing the thickness of color filter,and the color gamut can increase 21.2%when the thickness of RGB resist increases from 1.7um to 2.6um,but its efficiency will decrease by 28.2%.Secondly,optimized technology of high color gamut backlight module is been researched.The influences of blue chip LED excite yellow phosphor(1-P LED)backlight on color gamut are analyzed.The simulation and experiment demonstrate that optimized 1-P LED will take 8%improvement on color gamut compare to the unoptimized 1-P LED.Then the simulation and experiment by using blue chip LED excitered red and green phosphors(2-P LED)backlight shows that it will take 19%improvement on color gamut compare to 1-P LED backlight,and the otimized 2-P LED even can take 23%improvement.Then,a quantum dot enhancement film(QDEF)backlight is used to enhence color gamut.The simulation and experiment reveal that QDEF backlight can increase 36%color gamut compare to 1-P LED backlight,and the optimized QDEF backlight even can take 42%improvement.Finally,two problems of high color gamut LCD is been researched.For the reddish problem in white picture during large viewing angle,a method of quick judgment on reddish is put forward to anasys the problem.The array layers are key point to reddish problem by using the method above.An optimum condition of buffer layer which SiNx/SiOx =500A/1500A is got by simulation and verification,and the white picture quality get an obviously improvement under the condition.For the transmittance decrease problem for high color gamut LCD,this paper explores the matching between polarization state of the backlight and the polarizer.The result shows that the transmittance will increase 8.5%when the absorption axis of down polarizer parallel to the brightness enhancement film compare to the absorption axis of down polarizer perpendicular to the brightness enhancement film.In summary,this paper systematically study the program of enhencing color gamut of LCD,and solve the problems that high color gamut LCD bring.The results provide a theoretical and practical basis to high color gamut of LCD research and production engineering.