Theoretical Simulation And Experimental Verification Of Light-color Conversion In Quantum-Dot Backlight

Due to the advantages such as low cost,low power consumption,long service life,liquid crystal display technology(LCD)has gradually occupied the mainstream of flat panel display products.However,its color characteristics are still its short boards.Therefore,the study of LCD technology with wider color gamut performance is an inevitable trend in the near future.The quantum-dot(QD)backlight technology can not only improve the efficiency of LCD device,but also effectively enhance the color reproduction capability,which is considered as the most promising color gamut expansion scheme.At present,QD backlight technology still exists some key issues to be break through.These issues have become the main research goal of this research.In this research using the QD scattering dot as a basic structure,the spectral function model of QD backlight is constructed.A complete theoretical design system is established among the intensity distribution of the source,the QD scattering dots and the illuminance distribution of the emitting surface on light guide plate.The effects of key parameters on the performance of the QD backlight module are analyzed through modeling and simulation.The effective design of the QD backlight module is finally achieved through the prototype preparation and performance characterization.At the same time,this design method has universal significance in other LED lighting applications.The main research content of this topic includes the following parts:Firstly,this thesis researches the light mixing theory of photoluminescence QD backlight under CIE1931 chromaticity system.By using Gaussian curve fitting,the spectral function model of QD backlight is established,and a mutual conversion method between QD spectrum and color coordinates is further proposed.The color characteristic of white-balance QD backlight is evaluated.Accurate and efficient mutual conversion between the spectrum and color coordinate is verified.This method simplifies the basic function form and numerical computation of the spectral curve.It also provides necessary technical basis and theoretical guidance for the realization of the white-balance experiment of QD backlight.Secondly,the illuminance distribution of the bottom surface on a backlight module with edge-lit LED light sources is calculated,the mapping relation between the energy transmission of the light source and the radius distribution of the scattering dots is deduced,and the density distribution model of the scattering dots is designed effectively,which achieves the design target of high efficiency and uniformity.The results lays a theoretical foundation for the follow-up research.At the same time,this method has universal research significance in the research of patterned QD backlight system.Thirdly,by combining the mutual light-color conversion theory of QD backlight with the scattering-dot distribution model,this research establishes a solid simulation model of the QD backlight module and the corresponding scattering-dot array based on the Matlab-Lighttools data exchange channel.The QD fluorescence properties and parameters of the scattering particles are set according to experimental values.The influence of key parameters on the performance of the QD backlight module is analyzed.The orthogonal experimental method is designed and performed to simulate the quality ratio of the red/green QDs and the scattering particles.The results provide theoretical guidance and basis for further experiment.Fourthly,based on the design theory and simulation model proposed above,the prototype of the QD backlight module is prepared and assembled,and the influence of ink-return frequency of the screen printing process on the luminance and the CIE color coordinates is studied.The uniformity of the prototype is tested and analyzed,and the multiple linear regression model is established to discuss the effect of the mass ratio of red/green QDs on the CIE color coordinates.Finally,the proposed design is conducted in a flexible bending light guide plate for further basic application study,which proves its validity,practicability and extensibility.