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摘要: 为满足便携式投影仪的市场需求,设计了一种基于LED微型阵列的投影系统。该系统由显示单元和投影物镜构成。采用尺寸为12 mm×9 mm的自发光LED微型阵列作为系统的显示单元,利用光学设计软件设计了投影物镜。投影物镜采用反远距光学结构,全视场角为80°,焦距为8 mm,属于强光、广角镜头。在空间频率20 lp/mm处,该物镜的调制传递函数大于0.85,畸变小于2%,符合投影系统的设计要求。该投影系统具有体积小,结构简单,投影效果好,易加工等诸多优势,可为第三代投影技术的发展提供参考。Abstract: In order to meet market demand for portable projectors, a projection system using an LED micro array and composed of a display light source and an imaging system is designed. The size of the self-luminous micro-LED array is 12 mm×9 mm. This micro-LED array is used as the light source. A projection lens suitable for the light source is designed by using Zemax software. The projection adopts an anti-distance optical structure with a full field-of-view angle of 80 degrees and a focal length of 8 mm. This projection uses a strong-light and wide-angle lens. The modulation transfer function of the objective lens is greater than 0.85 at a spatial frequency of 20 lp/mm and its distortion is less than 2%, which meets the design requirements of the projection system. The projection system has many advantages, such as a small size, a simple structure, good projection, easy production, etc.. It can also provide reference for the development of third-generation projection technology.
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Key words:
- Micro-LED /
- pico-projection /
- display light /
- imaging system /
- wide field
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表 1 Micro-LED阵列参数表
Table 1. Parameters of micro-LED display
Arrays type Panel size/mm Length-width ratio Pixel size/μm Pixel amount Red micro-LEDs 12×9 4:3 25×25 480×360 Green micro-LEDs 12×9 4:3 25×25 480×360 Blue micro-LEDs 12×9 4:3 25×25 480×360 Total pixels (480×360)×3 表 2 投影物镜相关参数及设计指标
Table 2. Optical technology parameters and design specifications
Parameters Specifications Chip size (diagonal)/mm 15 Focus length/mm 8 FOV/(°) 80 Wavelength/nm 400~700 F/# 2.5 Prism thickness/mm 20 Prism material LAF13 MTF MTF≥0.5@20 lp/mm Distortion ≤3% 表 3 光学系统公差范围
Table 3. Tolerance range in this optical system
Parameter Value Radius (fringes) N=2 Thickness/mm 0.02 Decenter X/Y/mm 0.02 Tilt X/Y(degrees) 0.008 3 S+A Irregularity (fringes) ΔN=0.2 Index of refractive 0.000 1 Abbe number/% 1 表 4 20 lp/mm处光学系统的MTF
Table 4. MTF at 20 lp/mm in this optical system
Parameter Value Nominal 0.901 Best 0.899 Worst 0.762 Mean 0.866 Standard deviation 0.029 -
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