| As an important branch of modern display technology,projection technology has been widely used for its advantages of small size,easy to use and low cost.DLP,LCD and LCOS projection systems require additional lighting sources,resulting in complex system structure and low light energy utilization,which limits the development of projection technology to miniaturization,lightweight and low energy consumption.As an active light-emitting display device,Micro LED array has the advantages of high brightness,long life and fast response.Because of its high density arrangement of micron pixel size,it can meet the needs of high brightness and high resolution display at the same time.Micro LED array has a wide application prospect in micro display,micro projector,augmented reality and other fields.In order to realize the application of Micro LED in projection display system,this thesis carries out research on the micro projection system based on full-color Micro LED.The main contents include:(1)Research was carried out on a full-color Micro LED micro projection system based on the performance advantages of Micro LED in brightness,resolution and contrast.According to the index of the system,a projection lens was designed with a field of view of 60°,focal length of 18 mm,MTF>0.5 and distortion<3%.Aiming at the large divergence angle characteristics of Micro LED,the micro-mirror and micro-lens array structures for Micro LED array were designed.The simulation results show that the micro-lens array can reduce the divergence angle of Micro LED from 120°to18.07°,which improves the light energy utilization rate of the projection system.(2)Research was carried out on the fabrication technology of Gn N-based blue Micro LED arrays for projection display.We fabricated a flip-chip blue Micro LED array with pixel size of 20μm was fabricated by dry etching,groove filling and film deposition.The beam divergence angle of the array is 120°,and the color coordinate is(0.1684,0.0212)when the injection current density is 330 A/cm~2.At the same time,the size effect of Micro LED array is studied.The theoretical and experimental results show that the equivalent resistance increases with the decrease of Micro LED size,and the current density increases.The spectral width of Micro LED increases with the decrease of its size.(3)The simulation analysis of quantum dots excited by blue Micro LED was carried out,and the fabrication method and luminescence performance of quantum dot color conversion layer were studied.Firstly,we established the radiation model of quantum dot pixels excited by blue Micro LED.The concentration of quantum dots and the thickness of pixels are obtained by simulation analysis when the radiation light intensity is the highest,which provides the basis for the structure and size design of quantum dot pixels applied to projection display.Then the red-green two-color perovskite quantum dot color conversion layer that can be bent was prepared with microfluidics.Finally,the luminescence performance of the quantum dot color conversion layer on the double-layer PDMS substrate was tested in the plane and bending state.The CIE area change of full-color Micro LED before and after bending is less than 4%,which meets the needs of full-color display.(4)Research was carried out on the integration and performance test of Micro LED projection display system are studied.The micro projection system integration based on red,green and blue monochrome Micro LED chip is completed.The image color separation caused by the mechanical alignment error of the chips is corrected by the image correction algorithm.The illumination of the projection image is 78.97μW/cm~2,the uniformity of the illumination is 94.3%,and the gamut area is 107%NTSC.Then,a single-chip full-color Micro LED array device based on blue Micro LED chip and red-green quantum dot color conversion layer is fabricated,and a micro projection system based on color conversion technology is integrated to realize projection display. |
PDF Full Text Request