基于漫反射间接照明的自由曲面设计及反馈优化方法研究
发布时间：2018-09-17 19:56
【摘要】：发光二极管(LED,Light Emitting Diode)与传统光源相比,具有节能、环保、寿命长和体积小等诸多优势。由于LED光源辐照分布的特点,有必要对其进行适当的二次光学设计来满足实际的照明要求。因此,本文首先设计符合要求的漫反射自由曲面,并结合LED光源阵列来构建一个基于漫反射的间接照明系统,改善目标平面上的照度均匀性以及提高系统的光能利用率;接着又提出了反馈优化初始面型的概念,初始漫反射半球经过一次反馈优化,形成了满足要求的新面型轮廓,其优化结果不仅使目标面上的均匀度由原来的75%提高至80%,而且光能利用率也有所提高。本文针对近场、远场两种照明情况,分别以改善预期目标面上的高辐照均匀度和光能利用率为目标,提出基于多种LED光源阵列与漫反射自由曲面构成的间接照明方法。首先,考虑到LED点光源的朗伯特性,光线依据辐射分布模型射向漫反射自由曲面的内表面,结合漫反射自由曲面内表面的双向散射分布函数,能够完成内表面的二次反射,光线最终投在预设的目标面上;其次,由能量守恒定律计算得到期望目标面上的光照均匀度。因此,本文构建由LED光源阵列、漫反射自由曲面以及预设目标面组成的漫反射间接照明系统,同时可以计算得到目标面上期望照度值Et。最后,解出自由曲面的面型数据,同时利用TracePro光学软件对目标面上的光照均匀性、光能利用率进行大规模的仿真测试。实验结果表明:相比于传统的直接照明和漫反射半球作为面型的间接照明方法,本文设计的漫反射自由曲面在相同条件下使目标面具有更好的照度均匀性以及更高的光能利用率。在初始模型未能达到目标面上照明要求的情况下,本文又提出了依据初始仿真结果进行反馈优化的方法。通过将实际照度与期望照度之间的照度差△E反馈到设计流程中,可以得出初始漫反射半球经过一次反馈优化的新面型。出于简化模型考虑,本文只选择了半球作为初始面型并且只对目标平面上的圆形光斑进行研究,其目的是分析该反馈优化方法在自由曲面设计上的可行性。对于给定的圆形光斑,经过一次反馈优化设计,该目标面上的光照均匀度由原来的75.7%提升到80.8%,其光能利用率也从原先的12.6%上升至15.7%。结果表明:该反馈优化方法在一定程度上可以改善目标平面上的照度均匀性。
[Abstract]:Compared with traditional light source, LED,Light Emitting Diode) has many advantages, such as energy saving, environmental protection, long life and small size. Due to the characteristics of the radiation distribution of LED light source, it is necessary to carry out a proper secondary optical design to meet the actual lighting requirements. Therefore, in this paper, we first design the diffuse reflection free-form surface, and combine with the LED light source array to construct an indirect illumination system based on diffuse reflection to improve the uniformity of illumination on the target plane and improve the utilization rate of light energy of the system. Then the concept of feedback optimization initial surface shape is put forward. After a feedback optimization, the initial diffuse reflection hemispheres form a new profile that meets the requirements. The optimization results not only improve the uniformity of target surface from 75% to 80%, but also improve the utilization ratio of light energy. Aiming at the near field and far field illumination, this paper presents an indirect illumination method based on multiple LED light source arrays and diffuse reflection free-form surfaces, aiming at improving the high irradiation uniformity and light energy utilization on the expected target surface, respectively. Firstly, considering the Lambert characteristic of the LED point light source, the light can be injected into the inner surface of the diffuse free surface according to the radiation distribution model, and combined with the two-way scattering distribution function of the internal surface of the diffuse free surface, the secondary reflection of the inner surface can be accomplished. Finally, the light is cast on the target plane. Secondly, the illumination uniformity on the desired target surface is calculated by energy conservation law. Therefore, a diffuse reflection indirect illumination system composed of LED light source array, diffuse reflection free-form surface and preset target surface is constructed, and the expected illuminance value Et. on the target surface can be calculated at the same time. Finally, the surface data of the free-form surface is solved, and the illumination uniformity and light energy utilization ratio on the target surface are tested by TracePro software on a large scale. The experimental results show that: compared with the traditional direct illumination and diffuse reflection hemispheres as the surface of indirect lighting, The diffuse reflection free surface designed in this paper can make the target mask have better illumination uniformity and higher light energy utilization ratio under the same conditions. When the initial model fails to meet the lighting requirements on the target surface, a feedback optimization method based on the initial simulation results is proposed in this paper. By feedback the illumination difference E between the actual illumination and the expected illumination into the design process, a new shape of the initial diffuse reflection hemisphere can be obtained by one time feedback optimization. In order to simplify the model, this paper only selects the hemispheres as the initial surface and only studies the circular spot on the target plane. The purpose of this paper is to analyze the feasibility of the feedback optimization method in the design of free surface. For a given circular spot, after a feedback optimization design, the illumination uniformity on the target surface is increased from 75.7% to 80.8.The light energy utilization ratio is increased from 12.6% to 15.7g. The results show that the feedback optimization method can improve the illumination uniformity in the target plane to some extent.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN312.8;O435.1
本文编号：2246929
[Abstract]:Compared with traditional light source, LED,Light Emitting Diode) has many advantages, such as energy saving, environmental protection, long life and small size. Due to the characteristics of the radiation distribution of LED light source, it is necessary to carry out a proper secondary optical design to meet the actual lighting requirements. Therefore, in this paper, we first design the diffuse reflection free-form surface, and combine with the LED light source array to construct an indirect illumination system based on diffuse reflection to improve the uniformity of illumination on the target plane and improve the utilization rate of light energy of the system. Then the concept of feedback optimization initial surface shape is put forward. After a feedback optimization, the initial diffuse reflection hemispheres form a new profile that meets the requirements. The optimization results not only improve the uniformity of target surface from 75% to 80%, but also improve the utilization ratio of light energy. Aiming at the near field and far field illumination, this paper presents an indirect illumination method based on multiple LED light source arrays and diffuse reflection free-form surfaces, aiming at improving the high irradiation uniformity and light energy utilization on the expected target surface, respectively. Firstly, considering the Lambert characteristic of the LED point light source, the light can be injected into the inner surface of the diffuse free surface according to the radiation distribution model, and combined with the two-way scattering distribution function of the internal surface of the diffuse free surface, the secondary reflection of the inner surface can be accomplished. Finally, the light is cast on the target plane. Secondly, the illumination uniformity on the desired target surface is calculated by energy conservation law. Therefore, a diffuse reflection indirect illumination system composed of LED light source array, diffuse reflection free-form surface and preset target surface is constructed, and the expected illuminance value Et. on the target surface can be calculated at the same time. Finally, the surface data of the free-form surface is solved, and the illumination uniformity and light energy utilization ratio on the target surface are tested by TracePro software on a large scale. The experimental results show that: compared with the traditional direct illumination and diffuse reflection hemispheres as the surface of indirect lighting, The diffuse reflection free surface designed in this paper can make the target mask have better illumination uniformity and higher light energy utilization ratio under the same conditions. When the initial model fails to meet the lighting requirements on the target surface, a feedback optimization method based on the initial simulation results is proposed in this paper. By feedback the illumination difference E between the actual illumination and the expected illumination into the design process, a new shape of the initial diffuse reflection hemisphere can be obtained by one time feedback optimization. In order to simplify the model, this paper only selects the hemispheres as the initial surface and only studies the circular spot on the target plane. The purpose of this paper is to analyze the feasibility of the feedback optimization method in the design of free surface. For a given circular spot, after a feedback optimization design, the illumination uniformity on the target surface is increased from 75.7% to 80.8.The light energy utilization ratio is increased from 12.6% to 15.7g. The results show that the feedback optimization method can improve the illumination uniformity in the target plane to some extent.
【学位授予单位】：华东交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TN312.8;O435.1
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