阵列式微型透镜封装多芯片COB LED的光学仿真设计及应用

为了提高COB LED的取光率,以1919 COB LED为研究对象,建立阵列式圆锥透镜、半椭球透镜、四棱锥透镜和半圆球透镜封装LED模型,并利用光学仿真软件进行研究。仿真实验结果表明:在优化条件下,高0.5 mm、直径0.9 mm的阵列圆锥透镜封装LED的光通量由平面封装的67 lm提高至84.3 lm,即取光率提高25.8%。制作了RGB芯片的多芯片LED样品,并用直径1 mm的阵列半圆球透镜进行封装,其取光率提高18.8%。     

High uniform illumination of light-emitting diodes lighting with applying the multiple-curvature lens

Light-emitting-diode (LED) sources will play a very important role in the future. Nowadays, there are many traditional light sources gradually being replaced by LED sources. From the viewpoint of illumination, different environments have the same requirement uniformity of illumination. The basic reason for this is to insure human comfort. Therefore, the promotion of illumination uniformity is an especially important key issue. In this article, we propose one effective design to improve the uniformity of illumination of LEDs with Lambertian radiation profiles by inserting into the lighting system, multiple-curvature lens. The enhanced illumination uniformity of LEDs, in this system, is due to energy redistribution by controlling the direction of incident light, using geometrical optics theory. Ray tracing was applied for the simulations required. Finally, the uniformity of illumination is 76.17% in LEDs using multiple-curvature lens, which is twice the uniformity of conventional LEDs. Furthermore, the phenomenon of overload in the multiple-curvature lens is reduced by increasing the numbers of rings on the lens. The overload is less than 0.02 lm in the case of lens designed with 23 rings.     

用于CF-LCoS投影偏置LED照明光棒的角度分割原理及其偏振复用系统

研究了LED相对光棒中心位置存在偏置时光棒对LED的角度分割与虚像形成原理,籍此计算了不同偏置以及不同尺寸LED的光棒尺寸,再将计算所得的光棒与前端成像透镜、中间像面偏振复用系统、后端积分透镜及偏振分束器等进行综合优化设计,然后根据所得中间像确定不同情况下的偏振复用系统具体结构,确保LED发散角范围内光能的偏振复用,并实现对滤色片式硅基液晶芯片的均匀照明.最后设计了一款以白光LED为光源的滤色片式硅基液晶芯片微型投影光引擎,在1W LED功耗下实现12.8lm投射亮度(114lm/W),均匀性达93%.对比没有应用偏振光复用的微型投影光引擎,在保证均匀性的前提下,提升了微型投影系统的光效率,丰富了光棒偏振复用的内容.     

TIR透镜优化设计在LED微投影显示系统中的应用

发光二极管（lighting emitting diode,LED）取代传统光源作为投影仪,特别是微投影显示系统的光源是一种趋势。采用由非球面构成的TIR透镜代替锥形光管和CPC集光器,并通过整个系统最终在目标屏上形成的照明效果为依据,对TIR透镜的内部结构尺寸参数进行优化设计,采用经过优化设计的TIR 透镜作为对LED光源所发光束进行收集整形的光学元件,克服了在传统投影显示系统中经常出现的锥形光管或复合抛物面集光器 (compound parabolic concentrator,CPC) 给整个系统所带来的光学体积大的缺点。以单片式LCOS（liquid crystal on silicon）结构为基础,利用RGB LED时序方式进行混色,设计了一套LED微投影显示系统,并通过光线追迹程序对其光学性能进行模拟评估。结果表明：在考虑时序混色方式影响的情况下,整体系统光能效率为2.38%,系统光学体积仅为125cm3,达到了对系统结构简单紧凑的设计要求。     

大角度直下式LED背光透镜的设计

液晶显示领域不断提出缩减成本方案,对于液晶电视LED背光系统,提出了一种大角度背光透镜设计方案,即在目标接收屏面具有较大照度辐射角度的背光透镜设计。采用特定的双自由曲面设计,入光孔设置为类椭圆型结构面将光源出射的光通量进行等角度划分,根据接收屏面的理想照度分布与入光孔每一角度出射光通量对应关系计算出出光面自由曲线。借助底部微结构处理,再根据模具及产品成型要求补全外观结构,得到符合设计指标的方案,有效地解决了因增大角度引起的黄斑问题,并达到目标接受面均匀度的要求。针对32英寸（81 cm）的液晶电视背光模组,采用12颗最大正向电流为350 mA的LED灯珠,在模组高度为30 mm的系统中,设计的背光透镜模组达到了要求的亮度及均匀度。     

通用型数字鱼眼镜头检测系统的设计

设计了一种通用型数字鱼眼镜头检测系统,由照明系统、检测标板、等效平行平板系统和球幕组成。照明系统内部设有平面反光镜、柱体蝇眼透镜阵列、准直物镜,起到了缩小系统体积,提高光能利用率和照明均匀性,以及实现照明光斑大小尺寸可调的作用。其球幕内壁刻有角度分划尺,用于测量被测镜头的视场角。测试系统的照明视场范围为φ8.1 mm~φ36.3 mm,照度均匀度达到91%,光通量大于5 000 lm,且大小可调。检测系统可实现对芯片尺寸为0.55″~1.55″的1DLP、3DLP、3LCD、3LCOS的各种类型的数字投影或放映鱼眼镜头的像方视场角、分辨率、彩色还原性能、色差等性能和放映效果进行测试,降低了检测成本,通用性强。     

双层荧光粉涂覆对COB封装LED出光的影响

为了提高LED出光量,基于传统的荧光粉涂覆设计了一种双层荧光粉涂覆结构。通过对上下涂覆层浓度及上层涂覆量的研究,探究双层涂覆结构对COB封装LED出光的影响。结果表明在通电电流为440 mA时,可在实验中实现15 W的COB封装结构的白光LED:涂覆单一黄色荧光粉,上下层胶粉比为14.2～28且上层涂覆体积为下层的0.8倍时,COB封装LED的光通量为2 179 lm,光效可达145.3 lm/W,显指为63,出光量最大提升为7.82%;荧光粉调整为黄绿粉和红粉的配合使用后,最终实现色温、光效及显指分别为4 854 K、129.7 lm/W和81.2。因此,双层荧光粉涂覆结构可以提高COB封装LED的光学性能,对实际生产有一定的应用价值。     

单颗LED实现远距离均匀照明系统设计

针对现有的LED照明系统体积大、结构复杂、工作距离短的缺点,提出一种轻量化、均匀性好、能够实现远距离照明的单颗LED投影系统的设计方法。从照明设计理论出发,结合非成像设计和成像设计方法,设计了由单颗大功率LED、聚光镜、孔径光阑和投影物镜组成的投影照明系统。聚光镜对LED出射的光线进行匀化并会聚于照明面位置,投影物镜将照明面处的光斑投影到指定距离的接收面上。系统采用全透射式结构,便于加工和装调;单颗大功率LED作为光源能够有效减小系统体积和质量。实验结果表明:系统能在3 m~3 km范围内形成均匀度大于90%的照明,成像质量良好,投影面畸变小于5%,能满足远距离均匀照明投影的要求。     

基于微分方程数值解的自由曲面透镜的设计

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。     

LED路灯的自由曲面二次透镜设计

配光是LED路灯应用的主要技术问题之一。道路照明要求LED路灯在路面为均匀性良好的矩形光斑,在道路外无污染,无眩光。采用Snell定律和光源扩展度守恒原理确定自由曲面的解析方程,借助Matlab工具,采用差分法求解建立的偏微分方程,得到自由曲面的数据组,用作图软件Pro/Engineer为自由曲面透镜建模,通过计算机仿真软件TracePro进行光路仿真检验设计结果,并对所得结果进行分析。设计一款内表面为椭球面,外表面为自由曲面的LED路灯透镜,实现了路面光照总均匀度0.75,纵向均匀度0.85的效果。     

基于LED照明与弱光收集的节能车灯双向二次配光设计

为进一步利用太阳能,提出了“双向”利用光线的LED车灯设计新理念。运用光路可逆原理与边缘光线原理,构造矩形复合抛物面,对LED车灯进行“双向”二次配光设计。计算了远光灯矩形复合抛物面反光杯所需的最大出光半角、理论长度,借助tracepro软件,模拟研究了该矩形复合抛物面结构的最高光通量、平均光通量、光通量利用率随长度的变化关系,进一步截取较理论长度综合光学性能更好的反光器应用长度L=130 mm,并在此长度下,模拟了该LED远光灯照度分布情况与弱光收集情况。该类型车灯的LED照明与弱光收集互为补充,双向提高了LED车灯空间重复利用率。在照明方面,该灯能够满足现行标准GB25991-2010的要求,相同照度下,照明范围更大;相同照明范围内,照度更高;在弱光收集方面,是对当前太阳能汽车非聚光模式收集太阳能的补充。     

Design of double freeform-surface lens for LED uniform illumination with minimum Fresnel losses

In this study, we demonstrated a double freeform-surface lens to realize uniform illumination and minimum Fresnel losses for light-emitting diode (LED). In the present design, the inner surface and outer surface of the freeform lens were designed simultaneously, thus the light path can be controlled more flexibly. The detailed calculation and design process were presented. Monte Carlo ray-tracing simulation and Fresnel losses calculation were conducted to validate the present freeform lens. The simulation and calculation results indicated that the present freeform lens could enhance the illumination uniformity greatly and realize minimum Fresnel losses as low as 7.67%.     

多边形棒状透镜出端辐射均匀性的研究

研究了用多角形棒状透镜产生高均匀性正方形和圆形照明的最佳结构参量.结果表明,对于正方形棒状透镜,输出端的照明均匀性随透镜的长度振荡变化,在某些特定长度达到极小值.对于圆形照明面积,比较了从三角到八角的六种多边形.利用三角形积分透镜可以获得最佳的照明均匀性,但光能利用率相对较低,六角形积分透镜可同时获得较高的照明均匀性和光能利用率.     

具有曲面反射面的高均匀度LED植物光源

目前植物工厂培养架所使用的LED光源模块光学结构简单,照度均匀度和混色均匀度难以保证,导致农作物的品质参差不齐。为了提高种植物品质,需要优化植物光源的照明效果,设计高均匀度的植物光源。本文针对这一问题提出并研究了一种倒置光源的植物培养架设计方案。将LED灯珠安置在种植面同侧,并结合曲面反射顶面对LED发出的光线进行进一步均匀分配,在植物培养架有限的种植空间内增加光线耦合距离和耦合程度,提高了培养架植物光源的均匀度。经过多次结构优化后,最终获得了一个照度均匀度为91.64%、混色均匀度为89.73%的高均匀度植物照明培养架。然后基于优化得出的植物光源,研究植物生长过程对照明效果的影响后表明植物在生长过程中均可获得良好的照明环境。最后研究了不同形状和不同配光曲线的灯珠对培养架均匀度和光能利用率的影响。     

基于照明的LED阵列研究与仿真

LED是21世纪的绿色光源,具有广阔的照明前景。近年来,LED灯具产品开发的种类越来越多,设计合适的LED灯具显得尤为重要。由于单颗LED的功率很小,作为照明来使用,要求在照明区域内具有一定的均匀光通量和照度,所以需要采用LED的阵列形式, 加大其发光亮度和 发光面积,改善光照的均匀性。该文 首先计算LED阵列的照度叠加,进而根据叠加公式对阵列仿真,分析两种LED阵列分布的仿真结果,得出不同阵列的分布特点,并比较两种阵列的特点,最后分析出不同阵列分布的适用灯具,为LED灯具设计提供可靠依据。     

Optical design and analysis of illumination system based on augmented reality北大核心CSCD

照明系统是增强现实光学系统的重要组成部分,其体积、照度均匀性、能量利用率直接影响增强现实照明系统的质量,因此在照明系统中对光源二次配光非常重要。针对增强现实系统的自由曲面透镜形式和照明系统开展研究,重点分析准直系统集光角度与体积的对应关系,在对光源准直系统的面型构建详细分析基础上,对中心透射边缘反射的折反射式准直系统的面型进行求解,结合偏微分方程法和划分网格法,设计了自由曲面透镜,该系统与偏振分光棱镜共同组成硅基液晶（liquid crystal on silicon,LCoS）照明系统。仿真分析结果表明:系统照度均匀性达到91.96%,若不计偏振影响,照明系统光学效率达到66.6%。该系统具有结构简单紧凑、体积小、质量轻、照度均匀性高等特点,满足增强现实眼镜的需求。     

Nonspherical LED packaging lens for uniformity improvement

Light emitting diode (LED) has more advantages compared with a traditional incandescent light bulb and a fluorescent lamp, such as small size, low quantity of heat, long life, low power consumption, fast response, plain packaging and ease of develop ment of a frivolous short product. A methodology is proposed to improve the uniformity of the LED illumination system. As a light source in a backlight unit (BLU), the requirement for optical characteristics of a LED is different from highly directional conventional ones. New diffused-type LEDs need to be developed to fulfill the requirement of the BLU industry. A non-spherical lens is designed to optimize uniformity, and a great improvement in uniformity from 28.4 to 64% is demonstrated. In the future, it may used in an LED display to improve the unevenness of illumination.     

Optical design of adjustable light emitting diode for different lighting requirements

<正>Light emitting diode(LED) sources have been widely used for illumination.Optical design,especially freedom compact lens design is necessary to make LED sources applied in lighting industry,such as large-range interior lighting and small-range condensed lighting.For different lighting requirements,the size of target planes should be variable.In our paper we provide a method to design freedom lens according to the energy conservation law and Snell law through establishing energy mapping between the luminous flux emitted by a Lambertian LED source and a certain area of the target plane.The algorithm of our design can easily change the radius of each circular target plane,which makes the size of the target plane adjustable.Ray-tracing software Tracepro is used to validate the illuminance maps and polar-distribution maps.We design lenses for different sizes of target planes to meet specific lighting requirements.     

A study of extended optimization of U-type rod for LED projectors

The paper proposes a new U-type integral rod for a miniature DLP projector's optical engine with a high-power LED source and L-type optics in order to minimize volumetric size of optical engine. In addition, Taguchi method is applied in this research in order to extendedly optimize the performance of optical engine after initial optimization by damped least square (DLS). A miniature optical engine with LED light source has the advantages of good power consumption, useable projected image, reasonable brightness and uniformity, compactness in volumetric size and decent performance specifically for high spatial frequencies. However, there are still rooms for development with regard to light efficiency and uniformity due to non-uniformity of LED light distribution. Two critical design methods are proposed in this research. Firstly, a “U-type integrator” working with high-power LED which not only causes rays to make a “U-turn” in order to minimize volumetric size of optical engine but also, after optimization, controls output uniformity well after extended optimization by Taguchi method. With regard to gain of optical efficiency, we also consider the factors of a U-type integrator: shape and length with a Taguchi optimizer. It is concluded that the newly developed design achieves good results for the performance and volumetric size of the module. Extended optimized parameter design is able to improve the luminous flux by 4.84%, the illumination uniformity 5.62% and the packing size by 12%.     

实现在不同场合中LED均匀照明的方法研究

 LED自身的发光特点限制了其在照明领域的应用,如何合理分配LED的能量,在目标面上形成理想的照度是一个值得研究的问题。就不同应用场合下如何进行光学设计进行分析,通过采用非成像光学设计中光学扩展度守恒方法得到透镜的方程,分别实现圆形均匀照明和矩形均匀照明,其中圆形照明面照度均匀性达到85%,矩形照明面照度均匀性达到75%,并建立了自由曲面透镜三维模型,结合Tracepro进行光线追迹。仿真结果表明：提出的方法满足相应的照明标准,验证了理论设计的合理性。