LED光源等效模型建立及均匀照度色度透镜设计
发布时间：2018-08-31 20:42
【摘要】：发光二极管（Light Emitting Diode，简称LED）具有节能环保、体积小、寿命长等优点，广泛应用于各种照明如路灯、阅读灯及室内照明等。LED直接输出光的光强分布近似朗伯分布，如果直接照明在目标面上将形成中心区域照度值比较高而边缘区域照度值较低的照度分布，这种照度分布是不适合用于照明。为了提高LED照明性能，设计照明光学系统改变LED的光分布具有重要的意义。对于设计照明光学系统而言，首要问题是建立一个光源模型。光源模型建立的是否精确，对设计照明光学系统非常重要。本论文中，我们采用了预测算法和全局优化算法的组合方法，可以实现自动寻找LED光源模型的等效参数，从而建立LED等效光源。这种方法不仅可以建立精确的单色光源模型，而且可以建立光色复合的光源模型，这种复合模型可以等效白光LED光源。本文围绕着LED光源等效模型的建立以及基于这种光源模型设计了自由曲面透镜使LED的输出光在照明面上形成了均匀的照度和色度分布，论文主要成果如下： 提出了一种建立单色LED光源等效光学模型的新方法，通过大量的模拟数据，使用BP神经网络算法建立LED光源等效参数与光强分布之间的隐性函数关系，构建等效LED光源模型的光强分布与实际LED光强分布相似度的评价函数，评价函数是以LED等效光源模型的参数为自变量的。评价函数值越小，光源模型的光强分布与实际光强分布越相似，我们通过模拟退火算法来寻找最佳的等效参数，使评价函数值达到最小。通过这种方法建立OSRAM两款LED的光源等效模型，得到模型的光强分布和实际LED的光强分布之间的归一化互相关系数NCC均在99%以上，证实了该方法的可行性。 分析了荧光粉层的浓度、厚度等参数对LED的光强分布和空间色温分布的影响。使用神经网络和模拟退火组合的优化算法，可以精确调控荧光粉参数，使其输出光的空间色温分布与预定的空间色温分布接近。以瑞丰光电的3535芯片为例，通过这种方法对荧光粉参数的调控，得到的荧光粉等效模型与该芯片空间色温分布的相似度非常高，NCC高达99.1%。使用相同的方法，建立光色复合模光源。光色复合光源的评价指标有两项：光强分布和空间色温分布。因此要建立光色复合模型光源必须使这两个指标都与实际LED光源接近。对瑞丰3535芯片的光源进行等效建模，建立的等效光色复合模型与实际芯片的光强NCC为97.5%，空间色温分布NCC=97.5%，可知所建立的光色复合模型可以与实际LED光色分布有很高的相似度，该方法可以较好的模拟白光LED光源。 基于建立的等效白光LED光源，我们设计了一个透镜使白光LED光源产生的光能够在照明目标面上产生均匀的照度和色度分布。该透镜是一个自由曲面透镜，透镜内表面是一个球面，，外表面是一个自由曲面，由于透镜的结构是旋转对称的，所以设计的时候我们可以只考虑自由曲面的一个轮廓进行设计，自由曲面的轮廓曲线采用了3次样条曲线。采取了手动调整初始结构，使其照度和空间色温分布比较接近理想的照度分布和空间色温分布。初始结构确定以后，通过TracePro软件的交互式优化功能作进一步的优化，均匀度分别为93%和91%，与优化之前的透镜产生的照度和空间色温分布相比均匀度分别提高了17%和8%。
[Abstract]:Light Emitting Diode (LED) has the advantages of energy saving, environmental protection, small size and long life. It is widely used in various lighting such as street lamps, reading lamps and indoor lighting. In order to improve the illumination performance of LED, it is important to design illumination optical system to change the light distribution of LED. For the design of illumination optical system, the first problem is to establish a light source model. In this paper, we adopt a combination of predictive algorithm and global optimization algorithm to automatically find the equivalent parameters of the LED light source model and establish the LED equivalent light source. In this paper, a free-form lens is designed based on the equivalent model of the LED light source and the free-form lens to form a uniform illumination and chromaticity distribution on the illumination surface.
A new method to establish the equivalent optical model of monochromatic LED light source is proposed. Based on a large number of simulation data, the implicit function relationship between the equivalent parameters of LED light source and the intensity distribution is established by BP neural network algorithm. The evaluation function of the similarity between the equivalent LED light source model and the actual LED light intensity distribution is constructed. The parameters of the LED equivalent light source model are taken as independent variables.The smaller the evaluation function value is,the more similar the light intensity distribution of the light source model is to the actual light intensity distribution.We use simulated annealing algorithm to find the best equivalent parameters to minimize the evaluation function value.By this method,we establish the light equivalent model of OSRAM two LEDs and get the light intensity distribution of the model. The normalized cross-correlation coefficient NCC between the intensity distribution and the actual LED intensity distribution is above 99%, which confirms the feasibility of this method.
The effects of phosphor layer concentration and thickness on the light intensity distribution and spatial color temperature distribution of LED are analyzed.The parameters of phosphor can be adjusted accurately by using the optimization algorithm of neural network and simulated annealing,so that the spatial color temperature distribution of the output light is close to the predetermined spatial color temperature distribution.Taking Ruifeng photoelectric chip 3535 as an example,the system is on. The equivalent model of phosphor obtained by this method is very similar to the chip's spatial color temperature distribution, and the NCC is as high as 99.1%. Using the same method, a photochromic composite mode light source is established. The light source of Ruifeng 3535 chip is modeled equivalently. The NCC of the equivalent light-color composite model and the actual chip is 97.5% and the space color temperature distribution is 97.5%. It is shown that the light-color composite model can be very similar to the actual LED light-color distribution. The method can simulate white LED light source better.
Based on the equivalent white LED light source, a lens is designed to make the light produced by the white LED light source produce uniform illumination and chromaticity distribution on the illumination target surface. So we can only consider one contour of the free-form surface when we design. The contour curve of the free-form surface adopts cubic spline curve. The initial structure is adjusted manually to make the illumination and spatial color temperature distribution close to the ideal illumination distribution and spatial color temperature distribution. The interactive optimization function was further optimized. The uniformity was 93% and 91% respectively. The uniformity was increased by 17% and 8% respectively compared with the illumination and spatial color temperature distribution produced by the lens before optimization.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM923.34
本文编号：2216102
[Abstract]:Light Emitting Diode (LED) has the advantages of energy saving, environmental protection, small size and long life. It is widely used in various lighting such as street lamps, reading lamps and indoor lighting. In order to improve the illumination performance of LED, it is important to design illumination optical system to change the light distribution of LED. For the design of illumination optical system, the first problem is to establish a light source model. In this paper, we adopt a combination of predictive algorithm and global optimization algorithm to automatically find the equivalent parameters of the LED light source model and establish the LED equivalent light source. In this paper, a free-form lens is designed based on the equivalent model of the LED light source and the free-form lens to form a uniform illumination and chromaticity distribution on the illumination surface.
A new method to establish the equivalent optical model of monochromatic LED light source is proposed. Based on a large number of simulation data, the implicit function relationship between the equivalent parameters of LED light source and the intensity distribution is established by BP neural network algorithm. The evaluation function of the similarity between the equivalent LED light source model and the actual LED light intensity distribution is constructed. The parameters of the LED equivalent light source model are taken as independent variables.The smaller the evaluation function value is,the more similar the light intensity distribution of the light source model is to the actual light intensity distribution.We use simulated annealing algorithm to find the best equivalent parameters to minimize the evaluation function value.By this method,we establish the light equivalent model of OSRAM two LEDs and get the light intensity distribution of the model. The normalized cross-correlation coefficient NCC between the intensity distribution and the actual LED intensity distribution is above 99%, which confirms the feasibility of this method.
The effects of phosphor layer concentration and thickness on the light intensity distribution and spatial color temperature distribution of LED are analyzed.The parameters of phosphor can be adjusted accurately by using the optimization algorithm of neural network and simulated annealing,so that the spatial color temperature distribution of the output light is close to the predetermined spatial color temperature distribution.Taking Ruifeng photoelectric chip 3535 as an example,the system is on. The equivalent model of phosphor obtained by this method is very similar to the chip's spatial color temperature distribution, and the NCC is as high as 99.1%. Using the same method, a photochromic composite mode light source is established. The light source of Ruifeng 3535 chip is modeled equivalently. The NCC of the equivalent light-color composite model and the actual chip is 97.5% and the space color temperature distribution is 97.5%. It is shown that the light-color composite model can be very similar to the actual LED light-color distribution. The method can simulate white LED light source better.
Based on the equivalent white LED light source, a lens is designed to make the light produced by the white LED light source produce uniform illumination and chromaticity distribution on the illumination target surface. So we can only consider one contour of the free-form surface when we design. The contour curve of the free-form surface adopts cubic spline curve. The initial structure is adjusted manually to make the illumination and spatial color temperature distribution close to the ideal illumination distribution and spatial color temperature distribution. The interactive optimization function was further optimized. The uniformity was 93% and 91% respectively. The uniformity was increased by 17% and 8% respectively compared with the illumination and spatial color temperature distribution produced by the lens before optimization.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM923.34
【参考文献】
相关期刊论文 前1条
1 蒋大鹏,赵成久,侯凤勤,刘学彦,范翊,张立功,褚明辉,申德振,范希武;白光发光二极管的制备技术及主要特性[J];发光学报;2003年04期
本文编号：2216102
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