自然光型LED平板灯光学设计

发布时间：2018-05-01 21:06

  本文选题：模拟自然光照明 + LED平板灯　； 参考：《华侨大学》2016年硕士论文

【摘要】：近年来随着LED照明技术的迅猛发展,LED照明灯具种类不断增加,其中平板灯因具有出光均匀、光线柔和等特点得到了广泛的应用。但目前LED平板灯普遍存在以下不足:在成本、效率方面,采用导光板的侧入式平板灯耦合效率低、成本高;采用直下式的平板灯需要灯珠数量大,生产效率低。在灯光质量方面,LED平板灯与现有大多数LED灯具一样,普遍存在蓝光溢出、显色性差等对人眼有害的缺陷。针对LED平板灯存在的上述两个主要问题,本论文研究了一种自然光型LED平板灯,采用无导光板侧入式结构,出光效率高、成本低,灯具出射光光谱接近自然光光谱,显色性好。论文首先介绍了自然光型LED平板灯的光源设计。基于线性光谱叠加理论,自然光型LED平板灯采用5种颜色LED灯珠按一定比例组合作为发光光源。通过求解超定方程组的非负最小二乘解,直接得到匹配目标光谱(自然光光谱)的最优LED组合比例,然后进行光谱合成。采用的灯条包含暖白光、冷白光、青色光、绿色光和红色光5种LED灯珠,得到五种LED的最优个数比例为12:3:7:3:11,不同LED灯珠采用周期性交叉排列。实验测得组合光源的色温为4500K、一般显色指数Ra达到92,接近自然光的色温和显色指数。论文接着介绍了特殊结构自由曲面透镜的设计。为了使LED混合光均匀分布在平板灯扩散板上,针对无导光板侧入式LED平板灯结构特点,利用网格划分法设计了一种可以实现侧方大范围照明的双自由曲面透镜。透镜内曲面用于对入射光进行汇聚,以抑制光线的全反射;外自由曲面用于控制出射光的方向,以实现均匀照明。仿真结果显示:单颗LED发出的光经透镜折射后可在扩散板上形成近似半圆形大范围照明光斑,出光效率达到0.93,且当单颗光源照明光斑半径与LED光源的距离比值R/L?4-10时,在300mm?300mm的扩散板上的照度均匀性可达85%以上。论文最后建立了自然光型LED平板灯仿真模型,根据平板灯的尺寸及各色LED的间距,设计了5种不同规格的透镜,并分别对5种LED在扩散板上的照明效果进行了模拟仿真。仿真结果显示:暖白光、冷白光、红色光、青色光和绿色光LED经相应透镜折射后,在360mm?240mm的扩散板上的均匀度分别达到86.2%、88.9%、83.4%、89.3%、85.4%。因此,不同颜色的光能够在扩散板上混色均匀,使平板灯出射光线接近自然光。
[Abstract]:In recent years, with the rapid development of LED lighting technology, the variety of LED lighting lamps has been increasing, among which flat panel lamps have been widely used because of the characteristics of uniform light, soft light and so on. However, at present, the LED flat-panel lamp has the following disadvantages: in cost and efficiency, the side-in flat-panel lamp with light guide plate has low coupling efficiency and high cost, and the use of direct-down flat-panel lamp requires a large number of lamp beads and low production efficiency. In terms of lighting quality, like most existing LED lamps, there are common defects such as blue light overflow, poor color rendering and so on, which are harmful to human eyes. In view of the above two main problems of LED flat panel lamp, this paper studies a kind of natural light type LED flat panel lamp, which adopts the side entry structure of no light guide plate, has high light efficiency, low cost, and the luminaire emission spectrum is close to the natural light spectrum and has good color rendering. Firstly, the light source design of natural light type LED flat lamp is introduced in this paper. Based on the theory of linear spectral superposition, the natural light LED flat-panel lamp uses five kinds of color LED lamp beads to combine as the light source in certain proportion. By solving the nonnegative least square solution of the overdetermined equations, the optimal LED combination ratio of the matching target spectrum (natural light spectrum) is obtained directly, and then the spectral synthesis is carried out. The lamp bars used include five kinds of LED lamp beads: warm white light, cold white light, cyan light, green light and red light. The optimum number ratio of the five LED is 12: 3: 7: 3: 11, and the different LED lamp beads are arranged periodically. The experimental results show that the color temperature of the combined light source is 4500K and the general chromogenic index Ra is 92, which is close to the color temperature and color index of natural light. Then the design of freeform curved lens with special structure is introduced. In order to distribute the mixed light of LED evenly on the diffusion plate of flat panel lamp, according to the structural characteristics of side entry LED flat lamp without light guide, a double free curved lens is designed by using grid division method. The inner surface of the lens is used to converge the incident light to suppress the total reflection of the light, and the outer free surface is used to control the direction of the emitted light to achieve uniform illumination. The simulation results show that the light emitted by a single LED can form a semicircular large range illumination spot on the diffusion plate after refraction of the lens, and the output efficiency is 0.93.The ratio of the radius of the illumination spot to that of the LED light source is R/L?4-10 when the ratio of the radius of the illumination spot to that of the LED light source is R/L?4-10. The illumination uniformity on the diffusion plate of 300mm?300mm can reach more than 85%. Finally, the simulation model of natural light LED flat panel lamp is established. According to the size of flat panel lamp and the spacing of LED, five kinds of lenses with different specifications are designed, and the illumination effects of five kinds of LED on diffusion plate are simulated. The simulation results show that the uniformity of warm white light, cold white light, red light, cyan light and green light LED on the diffusion plate of 360mm?240mm is 86.2% and 83.489.3%, respectively. Therefore, the light of different colors can be mixed evenly on the diffusion plate, so that the light emitted from the flat lamp is close to the natural light.
【学位授予单位】：华侨大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM923.34
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本文编号：1831047