Microlens array fabricated by a low-cost grayscale lithography maskless system

被引:35
作者
Aristizabal, Sergio Lopera [1 ]
Cirino, Giuseppe Antonio [2 ]
Montagnoli, Arlindo Neto [2 ]
Sobrinho, Aparecido Arruda
Rubert, Jose Benaque [2 ]
Hospital, Michel
Mansano, Ronaldo Domingues [1 ]
机构
[1] Univ Sao Paulo, Dept Engn Eletr, LSI PSI, Sao Paulo, Brazil
[2] Univ Fed Sao Carlos, Dept Engn Eletr, BR-13560 Sao Carlos, SP, Brazil
基金
巴西圣保罗研究基金会;
关键词
microlens array; maskless lithography; continuous phase profile; digital light projector; digital micromirror device; polydimethylsiloxane elastomer; electrostatic bonding; COUPLING EFFICIENCY; SENSORS; DESIGN; DEVICE;
D O I
10.1117/1.OE.52.12.125101
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
This work presents the fabrication of a contiguous f/# = f/15 Fresnel microlens array (MLA) by employing a low-cost home-built maskless exposure lithographic system based on a digital light projector technology by using Texas Instruments' digital micromirror device chip. A continuous diffractive phase relief structure was generated on a photoresist-coated silicon wafer, replicated in polydimethylsiloxane (PDMS) and electrostatically bonded to a glass substrate. The whole exposure time takes 10.8 min to expose a 2.4 x 2.4 mm MLA, with a resolution of 2.5 mu m. This exposure time is relatively short, enabling high throughput or fast prototyping. Optical characterization was carried out using a He-Ne laser source (lambda = 633 nm), by evaluating the maximum intensity of each spot generated at the MLA focal plane, Imax, as well as its sharpness by measuring their full width at half maximum (FWHM) intensity values. The resulting FWHM and maximum intensity spot average values were FWHMAVG = 20 +/- 8% mu m and Imax(AVG) = 0.71 +/- 7% a.u:, respectively. The quality of replication was evaluated by profile characterization of the resulting mold and replica based on step height measurement along 180 mu m. The maximum obtained difference was 32 nm, corresponding to 2.5% of the total mold height or lambda/20. AFM measurements were also carried out to quantify the roughness quality between mold and replica. The resulting RMS roughness was 4.73 nm (lambda/130) and 6.66 nm (lambda/95) for mold and replica, respectively. A comparison between theoretical and measured intensity profiles at the MLA focal plane was also carried out. A good correspondence between the results was found. Such an MLA can be applied as a Shack-Hartmann wavefront sensor in optical interconnects and to enhance the efficiency of detector arrays. (C) 2013 Society of Photo-Optical Instrumentation Engineers (SPIE)
引用
收藏
页数:8
相关论文
共 25 条
[11]  
Lin CP, 2003, J MICROMECH MICROENG, V13, P748, DOI 10.1088/0960-1317/13/5/330
[12]  
Monteiro D. W. L., 2002, CMOS BASED INTEGRATE, P78
[13]   Design and fabrication of a hybrid diffractive optical device for multiple-line generation over a wide angle [J].
Neto, LG ;
Roberto, LB ;
Verdonck, P ;
Mansano, RD ;
Cirino, GA ;
Stefani, MA .
APPLIED OPTICS, 2001, 40 (02) :211-218
[14]   Design, fabrication and testing of microlens arrays for sensors and microsystems [J].
Nussbaum, P ;
Volke, R ;
Herzig, HP ;
Eisner, M ;
Haselbeck, S .
PURE AND APPLIED OPTICS, 1997, 6 (06) :617-636
[15]   Microlens array produced using hot embossing process [J].
Ong, NS ;
Koh, YH ;
Fu, YQ .
MICROELECTRONIC ENGINEERING, 2002, 60 (3-4) :365-379
[16]   Coupling Efficiency Enhancement in Organic Light-Emitting Devices Using Microlens Array-Theory and Experiment [J].
Peng, Huajun ;
Ho, Yeuk Lung ;
Yu, Xing-Jie ;
Wong, Man ;
Kwok, Hoi-Sing .
JOURNAL OF DISPLAY TECHNOLOGY, 2005, 1 (02) :278-282
[17]   TECHNIQUE FOR MONOLITHIC FABRICATION OF MICROLENS ARRAYS [J].
POPOVIC, ZD ;
SPRAGUE, RA ;
CONNELL, GAN .
APPLIED OPTICS, 1988, 27 (07) :1281-1284
[18]   NON-GAUSSIAN IMAGING PROPERTIES OF GRIN FIBER LENS ARRAYS [J].
REES, JD .
APPLIED OPTICS, 1982, 21 (06) :1009-1012
[19]   Increasing the optical coupling efficiency of planar photodetectors: electron beam writing of an integrated microlens array on top of a MSM device [J].
Seabra, AC ;
Araes, FG ;
Romero, MA ;
Neto, LG ;
Nabet, B .
OPTICS IN COMPUTING 2000, 2000, 4089 :890-894
[20]   GRAY-SCALE MASKS FOR DIFFRACTIVE-OPTICS FABRICATION .1. COMMERCIAL SLIDE IMAGERS [J].
SULESKI, TJ ;
OSHEA, DC .
APPLIED OPTICS, 1995, 34 (32) :7507-7517