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%。     

Geometrical characterization techniques for microlens made by thermal reflow of photoresist cylinder

Microlens characterization is a prerequisite for improving fabrication process, and for satisfying the end user needs. In this paper we explore techniques to characterize geometrical properties of microlens made by thermal reflow: viz. microlens profile; radius of curvature; microlens height; contact angle and focal length. The geometrical characterization is done using techniques such as contact profilometry, scanning electron microscopy (SEM), optical microscopy, white light confocal microscopy and fluorescence confocal microscopy. All the above techniques are studied and compared, keeping in mind the characterization requirements of polymer microlens made by thermal reflow technique.     

紫外衍射微透镜阵列的设计与制备

为了提高紫外焦平面阵列的填充因子,可以通过微透镜阵列与紫外焦平面阵列的集成,以改善紫外焦平面阵列的探测性能。根据标量衍射理论设计了用于日盲型紫外焦平面阵列的128×128衍射微透镜阵列,其工作中心波长为350nm,单元透镜F数为F/3.56。采用组合多层镀膜与剥离的工艺方法制备了128×128衍射微透镜阵列,对具体的工艺流程和制备误差进行了分析,测量了衍射微透镜阵列的光学性能。实验结果表明:衍射微透镜阵列的衍射效率为88%,与理论值95%有偏差,制备误差主要来自对准误差和线宽误差。紫外衍射微透镜阵列具有均匀的焦斑分布,与紫外焦平面阵列单片集成能较好地改善器件的整体性能。     

高质量光刻胶微小透镜阵列的制作

本文对光刻胶熔融法制作微小透镜阵列的机理进行了进一步深入的理论和实验研究,特别是提出和研究了非球面表面的形成问题。对微小透镜,特别是非球面形成过程的参数控制,例如对光刻胶小圆柱的高度、熔融光刻胶和基片的接触角的控制进行了较详细的讨论。我们制出了具有较好性能的微小透镜列阵,并给出了测量结果以及实物和成象照片。最后,给出了一种建议采用的实时控制高质量微小透镜列阵形成的装置方案。     

基于液晶光调制器的夏克-哈特曼波前探测技术

微透镜阵列是夏克-哈特曼波前探测器的关键器件。利用液晶器件的空间相位调制特性,可实现微透镜阵列功能,且具有孔径和焦距可变的优点。论述了基于液晶光调制的夏克-哈特曼波前探测校正技术的特征、技术进展、及应用前景。     

微透镜阵列光学相控阵扫描技术研究进展

光学相控阵光束扫描技术在激光雷达、空间光通信和光开关等领域拥有巨大的应用潜力。微透镜阵列光学相控阵可以通过微透镜阵列间μm量级的相对位移同时对多个出射光束的二维倾斜相位进行调制,从而实现大角度二维光束扫描,具有出射口径大、结构简单、体积小、微惯性、多功能等优点。首先介绍了微透镜阵列光学相控阵的扫描原理,之后对微透镜阵列光学相控阵国内外的发展现状、应用和现阶段存在的问题进行了阐述,最后对微透镜阵列光学相控阵的发展趋势进行了展望。     

Diffractive Microlens Array Monolithic Integration with PtSi Focal Plane array

Diffractive microlens arrays can completely collect the light at the focal plane and concentrate it into a smaller spot size on the detector plane, the photodetector area can be substantially reduced. Increased gamma radiation hardening and noise reduction result from the decrease in photodetector sensitive area. The diffractive microlens arrays have been designed by considering the correlative optical and processing parameters for PtSi focal plane array. They have been fabricated on the backside of PtSi focal plane array chip by successive photolithography and Ar⁺ ion-beam-etching technique. The alignment of microlens array with PtSi focal plane array was completed by a backside aligner with IR light source. The practical processes and fabrication method are discussed. The performance parameters of PtSi FPA with diffractive microlens array are presented.     

Electrically controllable microlens array fabricated by anisotropic phase separation from liquid-crystal and polymer composite materials

Anisotropic phase separation has been used to fabricate an electrically switchable microlens array from nematic liquid crystals. Nematic liquid-crystal-based microlens arrays have been built with diameters of approximately 400 microm and natural focal lengths as small as 1.6 mm. The focal length of each microlens in the array can be changed in milliseconds by an applied electric field. These devices, which have no internal substructures to scatter light, offer higher efficiency and greater light throughput than polymer dispersed devices.     

Microlens array diffuser for a light-emitting diode backlight system

Microlens array (MLA) diffusers for light-emitting diode (LED) backlight systems have been developed. A high fill-factor photoresist mold for the MLA was fabricated using three-dimensional diffuser lithography, and the patterns were transferred to a nickel master mold for UV-curable polymer replication. The fabricated microlens had various paraboloidal profiles, and its aspect ratio was controlled from 1.0 to 2.1. The MLA diffuser showed a batwing radiation pattern with a radiation angle of 150 degrees. The fabricated MLA diffuser may greatly enhance the color-mixing characteristics of LED backlight systems and help reduce the number of LEDs required.     

基于微透镜阵列的LED光学性能

功率型发光二极管(LED)的发展迫切需要提高取光效率,基于微透镜阵列的二次光学设计是改善其取光效率的有效途径。建立了一种大功率LED的封装结构,二次光学设计采用了微透镜阵列技术,运用光线追踪法研究了这种封装结构的光学性能。分析结果表明:利用微透镜阵列技术能显著改善LED的光学性能,提高取光效率,能将LED的亮度衰减降低12%以上,得到了较好的效果。     

基于微透镜阵列匀束的激光二极管面阵抽运耦合系统分析

为了提升高功率固体激光器中激光二极管(LD)面阵抽运场性能,采用几何光学和数理统计分析的方法,建立了基于微透镜阵列匀束的LD面阵抽运耦合系统的数学与物理模型,对微透镜阵列参数与最终耦合输出抽运场参数之间的关系进行分析,明确了微透镜单元F数、微透镜通光单元数以及微透镜阵列空间周期参数的设计原则.经实验测试,优化设计完成的LD面阵抽运耦合系统光场不均匀度为7.9%,耦合效率为90.7%.     

Tuning a nano-pillar array for enhancing the photoluminescence extraction efficiency of GaN-based light-emitting diodes

We demonstrate the fabrication of hexagonal nano-pillar arrays at the surface of GaN-based light-emitting diodes (LEDs) by nanosphere lithography. By varying the oxygen plasma etching time, we could tune the size and shape of the pillar. The nano-pillar has a truncated cone shape. The nano-pillar array serves as a gradual effective refractive index matcher, which reduces the reflection and increases light cone. It is found that the patterned surface absorbs more pumping light. To compare extraction efficiencies of LEDs, it is necessary to normalize the photoluminescence power spectrum with total absorption rate under fixed pumping power, then we could obtain the correct enhancement factor of the photoluminescence extraction efficiency and optimized structure. The highest enhancement factor of the extraction efficiency is 10.6.     

Fabrication of PDMS microlens array by digital maskless grayscale lithography and replica molding technique

This paper presents a facile and effective method to fabricate microlens array in polydimethylsiloxane (PDMS). The microlens array model is fabricated in photoresist via digital maskless grayscale lithography technique and the replica molding technique is used to fabricate PDMS microlens array. A convex PDMS microlens array with rectangular aperture and concave PDMS microlens array with hexagonal aperture are fabricated. The morphological characteristics of the microlens arrays are measured by microscope and 3D profiler. The results indicate that the profiles of the PDMS microlens arrays are clear and distinct. This method provides a simple and low-cost approach to prepare large area, concave or convex with arbitrary shape microlens array, which has potential application in many optoelectronic devices.     

Fabrication of Refractive Microlens Array with no Dead Area

ＦａｂｒｉｃａｔｉｏｎｏｆＲｅｆｒａｃｔｉｖｅＭｉｃｒｏｌｅｎｓＡｒａｙｗｉｔｈｎｏＤｅａｄＡｒｅａＣＨＥＮＢｏＧＵＯＬｕｒｏｎｇＴＡＮＧＪｉｙｕｅＺＨＥＮＨｏｎｇｊｕｎＰＡＮＧＬｉｎｇＴＩＡＮＷｅｉｊｉａｎ（ＩｎｆｏｒｍａｔｉｏｎＯｐｔｉｃｓＲｅ...     

Microlens arrays etched into glass and silicon

Microlens arrays fabricated by melting photoresist were transferred by reactive ion etching (RIE) into glass (SiO₂) and silicon (Si). By controlling the etching rates of the mask and the substrate material, radii of curvature and focal lengths within a wide range can be achieved. For example, glass lenses with diameter 120 μm and focal lengths between 500 μm and 1500 μm were made. The scaling possibilities of microlens arrays, given the use of RIE, are discussed.     

Design and Fabrication of Silcon Microlens with Low SAG for 528(H) × 528(V) Infrared Charge-Coupled Device Application

Microlens array is an important optical element to improve the photosensitivity of charge-coupled device (CCD). In this paper, a monolithic integration technology between microlens and 528 × 528 element PtSi Schottky-barrier infrared charge-coupled device (IRCCD) with a pixel size of 30m × 30m has been developed. The microlens array with low sag and long focal length is designed based on geometrical optics theory. It is directly formed on the back side of the substrate in IRCCD chip using successive photolithography and A⁺ ion beam etching (IBE) technology. The microlens array is characterized by both surface stylus and point spread function (PSF). The experiment results of integration device between IRCCD and microlens array indicate that the optical signal response is improved obviously and a responsivity increase by a factor of 1.8 in the operation band.     

High-resolution beam steering using microlens arrays

Imaging or beam-steering systems employing a periodic array of microlenses or micromirrors suffer from diffraction problems resulting from the destructive interference of the beam segments produced by the array. Simple formulas are derived for beam steering with segmented apertures that do not suffer from diffraction problems because of the introduction of a moving linear phase shifter such as a prescan lens before the periodic structure. The technique substantially increases the resolution of imaging systems that employ microlens arrays or micromirror arrays. Theoretical, numerical, and experimental results demonstrating the high-resolution imaging concept using microlens arrays are presented.     

凹折射微透镜阵列的离子束刻蚀制作

利用光刻热熔成形工艺及离子束刻蚀制作 12 8× 12 8元凹微透镜阵列。所制硅及石英凹微透镜的典型基本图形分别为凹球冠形、凹柱形和矩顶凹面形。分析了在光致抗蚀剂柱凹微透镜图形制作过程中的膜系匹配特性 ,与制作该种微透镜有关的光掩模版的主要结构参数 ,以及光致抗蚀剂掩模工艺参数的控制依据等。探讨了在凹微透镜器件制作基础上利用成膜工艺开展平面折射微透镜器件制作的问题。采用扫描电子显微镜 (SEM)和表面轮廓仪测试了所制石英凹微透镜阵列的表面微结构形貌。给出了所制石英凹微透镜阵列远场光学特性的测试结果。     

扩展微透镜数值孔径范围的阶梯光刻热熔法研究

在微透镜阵列的光刻热熔制作法中，临界角效应严重影响了微透镜的制作范围和面形质量。在对临界角效应定性研究的基础上，提出了用阶梯光刻熔法来扩展热熔型微透镜阵列的数值孔径范围。实验结果表明，采用这一方法制作的微透镜，其单元孔径范围扩展为５０￣９００μｍ，相对口径范围扩大到为Ｆ／１￣Ｆ／１０，并有效地改善了临界角效应对大孔径微透镜面形质量的影响。     

一种大F数微透镜阵列的制备方法

针对大F数(大于10)微透镜阵列难以制备的现状,提出了一种制备大F数微透镜阵列的方法.首先采用传统光刻胶热熔法及刻蚀技术制作出成形的微透镜阵列,再将一层具有较高粘滞系数的光刻胶均匀地涂覆在该微透镜阵列上,在光刻胶的粘滞作用以及烘烤过程中光刻胶自身表面张力的共同作用下,微透镜阵列的F数得到提高.采用该方法制备的二氧化硅微透镜阵列的F数达40,与传统大F数微透镜阵列的加工方法相比,该方法简便易行、制备的微透镜阵列面形良好,且只需调节光刻胶的粘滞系数,即可获得F数不同的微透镜阵列.