Study On Packaging And Aging Properties Of Wide Color Gamut White LED

The application of quantum dots in LED can obtain a light source with high saturation and wide color gamut,which has a very attractive prospect in the backlight field of liquid crystal disIplay.However,the short-lived status of quantum dots has seriously affected the popularization and application,and its influencing factors include temperature,water and oxygen.At present,there are many researches on quantum dots in materials preparation and other aspects,but the effects of water and oxygen on their light attenuation properties are less studied.And the research on the spectral fitting of quantum dots is mostly just to study the color rendering by spectral superposition,but it has not been verified by the mass ratio of phosphors in actual production and cannot be applied to production.In this paper,quantum dots are used as research objects.Firstly,the water-oxygen isolation film is covered after film formation of quantum dots,and the green light quantum dot film is excited by blue LED to study its light-fading performance.Then a calculation method for exciting red and green quantum dots with white light by blue LED is proposed.The relationship between red and green quantum dot absorption,conversion rate and quantum dot amount is matched by MATLAB,and the corresponding white light color coordinate points are obtained.The amount of red and green light quantum dots,and the experiment verified its accuracy;Finally,the color gamut of the LED was calculated by using the wide color gamut white LED obtained by red phosphor(KSF)and green quantum dots,and the aging performance was studied.This work has achieved the following research results:Firstly,by covering the surface of the colloidal quantum dots and prolonging their lifetime,the experimental results show that the photo-damage performance of the single-layer SiO₂ film is improved compared with the sample without the separator.The double-layer SiO₂ film and the SiO₂/Al₂O₃ composite film can effectively reduce the pore size and pore density of the film,block the entry of water and oxygen,and further inhibit the light attenuation of the quantum dots;The inorganic film/organic film/inorganic film more effectively blocks water oxygen permeation and greatly prolongs quantum dot lifetime,in the long-term aging experiment,the optical power of the green quantum dots is basically stable.Secondly,in this paper,white light is obtained by exciting blue and green quantum dots of blue light,and the optical power spectrum corresponding to different quantum dots is measured.The relationship between the amount of red and green light quantum dot colloids and the absorption rate and conversion rate is fitted by MATLAB.The green and red spectra are superimposed to obtain the white light power spectrum,obtain the relationship between quantum dot usage and white light color coordinates,and the spectrum measured by the actual ingredients is basically consistent with the theoretical spectrum,which has a guiding role for the actual powder mixing work in the future.Thirdly,considering that the commercial red phosphor(KSF)is more stable than red light quantum dots and has a narrower half-width,it is more suitable for wide-color white LEDs.Therefore,the green light quantum dot,the KSF and the blue LED chip are used to package a white LED of a wide color gamut,and the color gamut calculated to the LED is measured to be a 104%NTSC standard color gamut.And using the thin film process to extend its life,through the room temperature aging experiment,it is found that the luminous flux of the LED is basically stable after lighting for 500h,so that the LED can be applied in practice.