非成像光学系统的LED光源优化设计与分析

发布时间：2018-06-09 11:25

本文选题：非成像光学 + 照度均匀度　；参考：《广东工业大学》2014年博士论文

【摘要】：随着现代电子产品对轻、薄、短、小、高可靠性、低功耗的不断追求,对电子制造装备的执行速度、操作精度及稳定性等提出了更高要求。现代电子制造装备的高速高精度操作基本都涉及到视觉技术,其中的光源设计及照明技术则直接影响到这类装备的性能指标。高速高精度的视觉定位与识别,要求在复杂工况下极短时间内获取高质量目标图像,其光源的设计对于这类高速运动的执行系统的图像获取起着关键性的作用。随着半导体照明技术的发展,发光二极管(LED)正逐渐取代传统光源,成为新一代光源。在非成像光学系统中,接收面的均匀照明以及光能的充分利用一直是光源设计急需解决的问题。本文面向电子制造装备研发中的光源设计需求,重点开展基于LED光源的照明显示系统研究。针对光源设计中接收面照度均匀与光能的充分利用之间难以兼顾的难题,提出同时考虑照明系统接收面的照度均匀度和光能利用率的LED光源光学系统设计新方法,研究可获得理想照明系统的光路设计理论,在综合考虑照度均匀度和光能利用率的基础上,提出光源系统的综合评价函数,并通过编程实现照明系统参数的自动调整,达到设计的最优化,分别实现反光杯式、透镜式光学系统照明接收面均匀光斑的获取,同时对其光路设计模型的光学追迹结果进行分析,进一步验证所提出的光路设计方法的正确性,可有效实现接收面照度均匀的同时提高光能的利用率,为LED光源光学系统的设计提供可行有效的解决方法。主要研究工作概括如下： (1)调研面向电子制造装备研发的视觉技术研究现状,了解这类装备在高速高精度运行条件下对光源设计提出的光能利用率及照度均匀性需求。深入调研非成像光学中光源设计方法的国内外研究现状及发展前景,分析目前非成像光学系统中多种照明光源的特性,确定采用LED光源为非成像光学系统的照明光源,指明目前LED光源设计领域仍然存在的难点问题,即难以在满足照明系统接收面的照度均匀的同时提高光能的充分利用率。 (2)在非成像光学系统设计过程中,首先分析非成像光学的广义光学扩展量、能量收集率等重要参数,建立广义光学扩展量和能量收集率理论最大值之间的关系,分析像差对能量收集率的影响因素以及LED的朗伯型发光特性；同时,研究光学模拟软件Trace pro的矢量法光束追迹理论,分析基于Monte Carlo随机理论的光照度计算方法,并引入非成像光学的参数分析LED发光模型,确定本系统所用LED光源类型；基于光学设计中的一次光学设计和二次光学设计方法,给出透镜设计所需的透镜表面生成公式,为光学系统的设计奠定理论基础。 (3)研究分析LED照明光学系统参数如二次曲面常数K和曲率半径R等对均匀圆形光斑的影响规律。提出综合考虑照度均匀度和光能利用率的最优设计方法,构建光源系统的综合评价函数,并采用TracePro软件的Scheme语言编程实现照明系统参数的自动调整,获取光学系统照明接收面的均匀光斑。基于该优化方法,研究设计反光杯结构的均匀照明系统,建立反光杯结构的综合评价函数,基于Taguchi method的编程方法,实现对反光杯K、R值以及反光杯和光源间距的自动调整,可快速准确获得照明系统的优化设计结果,使接收面(与光源相距100mm的位置)形成的直径为40mm圆形光斑的照度均匀度达1.5,光能利用率为69.0%。相比于理想抛物面反光杯照明系统的综合评价函数,本系统的综合评价函数与理想值的接近度提高了29.9%。 (4)鉴于反光杯在LED光源设计中存在高度限制的缺点,及透镜设计具有的更大自由度特点,本文进一步研究设计基于透镜结构的均匀照明系统。通过建立透镜系统的综合评价函数,对透镜二次曲面常数K及顶点曲率半径R进行程序的自动调节与优化,实现远距离(与光源相距800mm的位置)处直径为120mm的圆形均匀光斑,其光能利用率为51.7%,照度均匀度为1.51,所获取的最优设计系统的综合评价函数与理想值的接近度为50.3%,比单独调整R值时获得的接近度提高了22.5%。 (5)鉴于部分应用场合对光斑形状的不同需求,本文对面向光束准直的照明系统进行研究,通过透镜系统的优化设计获取接收面的方形光斑,实现在距离光源500mm处形成20mm*20mm的方形均匀光斑。通过建立光线经过透镜后的出射角与入射角之间的关系式,确定最小出射角；基于透镜表面生成公式建立透镜的K、R值与出射角之间的关系,揭示不同曲面透镜二次曲面常数K2值对接收面方形均匀光斑的影响规律,获得目标面上的方形均匀照明光斑,结果显示：椭圆型二次曲面可以获得光束出射角为6.049mrad,接近理论计算的最小出射角值,其照度均匀度达到93.02%；研究发现：相比较于双曲型二次曲面和抛物型二次曲面,椭圆面的照度均匀度分别提高了13.81%和13.22%,能更好地在接收面获得方形均匀照明光斑。在本文的最后,对整个课题所做的工作进行总结,并指出需要进一步研究和发展的方向。
[Abstract]:With the development of the semiconductor lighting technology , the light source design and the illumination technology have a key role in the design of the light source .

( 1 ) To investigate the present situation of the research and development of electronic manufacturing equipment , and to understand the light energy utilization and illumination uniformity requirements of the light source design under high - speed and high - precision operating conditions .

( 2 ) In the design process of the non - imaging optical system , firstly , the important parameters such as the generalized optical extension amount and the energy collection rate of the non - imaging optics are analyzed , the relationship between the generalized optical extension quantity and the maximum energy collection rate theoretical maximum value is established , the influence factors of the aberration on the energy collection rate and the Lambert - type light - emitting characteristics of the LED are analyzed ;
At the same time , we study the beam tracking theory of the vector method of Trace pro in optical simulation software , analyze the light illumination calculation method based on Monte Carlo stochastic theory , and introduce the parameters of non - imaging optics to analyze the LED lighting model to determine the type of LED light source used in the system ;
Based on primary optical design and secondary optical design method in optical design , the formula of lens surface generation needed for lens design is given , which lays a theoretical foundation for the design of optical system .

( 3 ) The influence of the parameters such as the quadratic surface constant K and the radius of curvature R on the uniform circular spot is studied and analyzed . A comprehensive evaluation function of the light source system is built . Based on the optimization method , the uniform illumination system of the light reflecting cup structure is constructed . Based on the optimization method , the illumination uniformity of the light reflecting cup K , R value and the distance between the reflecting cup and the light source is obtained . Based on the optimization method , the illumination uniformity of the light reflecting cup K , R value and the reflecting cup and the light source space is obtained .

( 4 ) In view of the disadvantages of high limit in the design of the LED light source and the more degree of freedom in the design of the lens , the uniform illumination system based on the lens structure is further studied in this paper . By establishing the comprehensive evaluation function of the lens system , the circular uniform light spot with a diameter of 120 mm at the distance ( the position of 800 mm from the light source ) is realized , the light energy utilization rate is 51.7 % , the illuminance uniformity is 1 . 51 , the approximate degree of the obtained optimal design system and the ideal value is 50.3 % , and the approximate degree obtained when the R value is adjusted independently is improved by 22.5 % .

( 5 ) In view of the different demands of some applications on the shape of light spot , this paper studies the beam - oriented illumination system , obtains the square spot of the receiving surface through the optimization design of the lens system , realizes the square uniform spot of 20mm * 20mm at 500mm from the light source , and determines the minimum exit angle by establishing the relation between the emergent angle and the incident angle of the light passing through the lens ;
The relation between the K , R value and the exit angle of the lens is established based on the surface generation formula of the lens , and the influence law of the quadratic surface constant K2 on the square uniform spot of the receiving surface is revealed , and the square uniform illumination spot on the target surface is obtained . The result shows that the elliptic secondary curved surface can obtain the minimum exit angle value of the beam exit angle of 6.049mrad and the approximate theory , and the illuminance uniformity reaches 93.02 % ;
The results show that the illuminance uniformity of the ellipsoid is increased by 13.81 % and 13.22 % , and the square uniform illumination spot can be obtained better at the receiving surface .

In the end of this paper , the work of the whole subject is summarized , and the direction of further research and development is pointed out .
【学位授予单位】：广东工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM923.34

【参考文献】