共查询到19条相似文献,搜索用时 531 毫秒
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实现LED照明的自由曲面透镜设计 总被引:14,自引:1,他引:14
为在特定平面上实现所需照明,从而满足各类LED照明系统的要求,通过透镜的第一面球面和第二面自由曲面的两次折射实现LED的配光设计.根据给出的LED辐射特性和所需实现的照明面上的能量分布,并预先定义透镜球面的结构参量,可得到一组一阶偏微分方程,数值差分求解直接求得透镜的自由曲面.光源采用发光面积1×1 mm2朗伯体发光的LED,视角180°,由自由曲面透镜得到的各种形状照明面的模拟均匀性皆接近90%,且能量利用率高于98%,编程解一阶偏微分方程组的计算时间少于20 s. 相似文献
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实现均匀照明的自由曲面反射器 总被引:19,自引:3,他引:19
通过单个自由曲面反射器的反射,令光源发出的能量重新分布,在特定照明面上实现所需照明,从而简化了投影设备中的照明系统,使设备的进一步小型化成为可能。根据给出的光源辐射特性和所需实现的照明面上的能量分布,可得到一组偏微分方程,数值差分求解直接得到自由曲面反射器。光源采用发光面积1 mm×1 mm朗伯体发光的LED,视角为120°,照明面为4:3的均匀矩形光斑。设计了两种自由曲面反射器,并用软件对得到的曲面进行了照明模拟,模拟得到的照明均匀性接近90%。两种反射器在光轴方向上的投影尺寸均小于25 mm,垂直光轴方向上投影长度均小于22 mm,照明系统总长均小于40 mm,结构紧凑,适用于小型LED投影设备。 相似文献
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为满足目标面上均匀照明的需求,设计了一款自由曲面透镜。根据LED光源的发光特点,结合光学成像的特性,非成像光学原理和能量守恒定理,推导出实现光能量在目标面上均匀分布的自由曲面面形的微分方程,采用matlab的ode算法求出面形上的离散坐标点,对离散坐标点拟合后得到透镜模型,通过光学模拟仿真软件对透镜模型进行光线追迹。结果表明,配光角度为80°的透镜,透镜的口径与光源发光面宽度之比大于等于9时,目标面上的照度均匀性大于0.9,光能利用率约为85%。该设计方法可以快速精确地设计出所需的透镜,而且透镜结构紧凑,单颗就能实现均匀照明,有利于LED光源照明系统的小型化。 相似文献
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用于固态照明的自由曲面微透镜设计 总被引:2,自引:0,他引:2
针对LED照明应用中,现有二次光学设计过程对LED初始光强空间角分布的依赖性,讨论了用于LED照明的自由曲面微透镜器件的设计方法.根据斯涅尔定律和边缘光学理论,研究了自由曲面微透镜的面形构造算法,建立了自由曲面微透镜器件的光学模型,并用光学模拟软件对其照明性能进行了模拟实验.结果显示,该微透镜器件能够在目标面上获得满足预期要求的照度分布,照明均匀度在92%以上,且其结构有效解决了LED初始光强空间角分布复杂化的现状和现有二次光学设计对光源初始光强空间角分布依赖性的矛盾. 相似文献
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实现LED矩形均匀照明的透镜设计 总被引:3,自引:1,他引:2
随着大功率LED发射光强的不断提高,采用单粒LED为光源的照明系统已得到普遍应用。设计一种以LED为光源实现矩形均匀照明的透镜,根据微分几何的理论建立透镜面型所满足的微分方程,然后根据能量映射关系和能量守恒定律建立面型与目标面坐标点之间的关系,并通过四阶龙格-库塔法求解微分方程得到面型数据,利用所得的面型数据在三维建模软件Rhinoceros中构建出所求透镜面型,并将透镜导入ASAP进行模拟。模拟结果表明:该光学系统效率达到94.01%,目标面照度均匀性优于92.73%。最后分析了自由曲面的连续性,指出能量映射关系决定着自由曲面的连续性。 相似文献
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一种实现大功率LED均匀照明的投射器设计 总被引:6,自引:3,他引:3
以特定区域的均匀照明为目标,设计一种以单粒LED为光源的均匀投射系统。根据LED的发光特性以及能量守恒定律选择采用折射 全反射(TIR)光学系统,通过建立TIR折射面及全反射面轮廓曲线上的点所满足的常微分方程,利用Runge Kutta求解常微分方程得到轮廓曲线上点的坐标,再在UG中对坐标点进行曲线拟合得到轮廓曲线,进而得到TIR模型及适合数控加工的面形数据。将TIR模型导入Tracepro并对投射系统追迹光线。模拟结果表明:目标平面的光照均匀度达到92.6%,系统的效率达到91.8%。 相似文献
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对于近场大角度的匀光照明系统,透镜的一般设计方法是采用内表面为球形的自由曲面透镜设计,计算的自由曲面透镜只需考虑一次折射。但是当角度达到一定范围时,在透镜的内表面容易发生全反射,导致目标面照度不均匀。为了在近场照明系统中得到更大角度的配光,提出一种以合适的抛物面作为自由曲面透镜的内表面的设计方法,内抛物面先对光源的能量进行一次扩散,再计算自由曲面面型,通过模拟仿真,实现了在距离光源15 mm处形成半径40 mm的光斑,均匀度达到95%,能量利用率达到97.8%,相对于传统的直下式透镜,提高了照明的均匀度,同时减少了箱体的厚度。 相似文献
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Spectral image acquisition as well as color image is affected by several illumination factors such as shading, gloss, and
specular highlight. Spectral invariant representations for these factors were proposed for the standard dichromatic reflection
model of inhomogeneous dielectric materials. However, these representations are inadequate for other characteristic materials
like metal. This paper proposes a more general spectral invariant representation for obtaining reliable spectral reflectance
images. Our invariant representation is derived from the standard dichromatic reflection model for dielectric materials and
the extended dichromatic reflection model for metals. We proof that the invariant formulas for spectral images of natural
objects preserve spectral information and are invariant to highlights, shading, surface geometry, and illumination intensity.
It is proved that the conventional spectral invariant technique can be applied to metals in addition to dielectric objects.
Experimental results show that the proposed spectral invariant representation is effective for image segmentation. 相似文献
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Masaru Tsuchida Yuri Murakami Takashi Obi Masahiro Yamaguchi Nagaaki Ohyama 《Optical Review》2001,8(6):444-450
A method to reproduce images of an object under various observation conditions is presented. In this method, a series of multispectral
images is captured by rotating the object under a point light source of which spectral power distribution and the position
are known. The captured images are decomposed into diffuse and specular reflection component images based on the dichromatic
reflection and the Lambertian models. Next, the incident angle of the illumination light and the angle between viewing direction
and regular reflection are calculated based on observation geometry. Finally, the image under observation geometry is synthesized
using the light-ray rearrangement technique. The experiments are carried out using two-dimensional objects, leather and fabric.
Most of the synthesized images are shown to be the same as the images actually captured under the assumed illumination geometry,
even if the object has complex reflection like fabric for which it is difficult to apply the reflection model used in computer
graphics. 相似文献
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An expression of degree of polarization(DOP) for metallic material is presented based on the three-component polarized bidirectional reflectance distribution function(p BRDF) model with considering specular reflection, directional diffuse reflection and ideal diffuse reflection. The three-component p BRDF model with a detailed reflection assumption is validated by comparing simulations with measurements. The DOP expression presented in this paper is related to surface roughness, which makes it more reasonable in physics. Test results for two metallic samples show that the DOP based on the three-component p BRDF model accords well with the measurement and the error of existing DOP expression is significantly reduced by introducing the diffuse reflection. It indicates that our DOP expression describes the polarized reflection properties of metallic surfaces more accurately. 相似文献
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Based on the three-component assumption that the reflection is divided into specular reflection,directional diffuse reflection,and ideal diffuse reflection,a bidirectional reflectance distribution function(BRDF) model of metallic materials is presented.Compared with the two-component assumption that the reflection is composed of specular reflection and diffuse reflection,the three-component assumption divides the diffuse reflection into directional diffuse and ideal diffuse reflection.This model effectively resolves the problem that constant diffuse reflection leads to considerable error for metallic materials.Simulation and measurement results validate that this three-component BRDF model can improve the modeling accuracy significantly and describe the reflection properties in the hemisphere space precisely for the metallic materials. 相似文献
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A compact ESPI system for displacement measurements of specular reflecting or optical rough surfaces
Ren Skov Hansen 《Optics and Lasers in Engineering》2004,41(1):305
A stable and compact speckle interferometer for doing out-of-plane displacement measurements on reflective as well as diffusely scattering object surfaces is demonstrated. The set-up is based on a nearly path length compensated interferometer of the Fizeau type and uses diffuse illumination of the object combined with a speckled reference wave. This combination eliminates the need for special optical components, and the interferometer can be built of commonly available components. The diffuse illumination wave is obtained by scattering coherent light from a diffusely scattering surface. The speckled reference wave is established by reflecting a part of the diffuse illumination wave from a glass plate placed in front of the object. Besides relaxing the alignment tolerances of the set-up, the diffuse illumination eliminates the need for any preparation of the surface under test, which turns the system into a candidate for testing micro mechanical systems. When using the interferometer for measurements of the eye, the risk of focusing the laser beam on the retina is decreased due to the diffuse object illumination. 相似文献