Application of 3D glycerol-compensated inclined-exposure technology to an integrated optical pick-up head
Application of 3D glycerol-compensated inclined-exposure technology to an integrated optical pick-up head
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DOI：
10.1088/0960-1317/14/7/019
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发表时间：
2004-07-01
影响因子：
2.3
通讯作者：
Tseng, FG
中科院分区：
文献类型：
--
作者：
Hung, KY;Hu, HT;Tseng, FG
提出了一种在片上菲涅尔透镜光学头中集成具有精确角度和光滑表面的倾斜反射镜的新方法。采用甘油补偿倾斜曝光技术制作了45 °反射镜对。该技术可以在厚度为100 ~ 1000 μ m的SU-8负性光刻胶上制作19- 90 °倾斜的结构。甘油在曝光期间用作折射率匹配材料，以补偿空气和SU 8之间的折射率差异，从而将可能的倾斜角度从54度（在空气中）扩展到19度（在甘油中）。为了消除反射诱导图案，CK-6020 L抗蚀剂被用作光刻胶层。通过AFM测量的表面粗糙度对于各种倾斜角度都小于7 nm。器件制造已成功完成，测试结果表明，功能VCSEL（垂直腔面发射激光器）光束聚焦在5妈妈点。进一步的光束尺寸减小到亚微米范围需要具有高数值孔径的物镜透镜，这不在本文的范围内。所制造的光学部件是鲁棒的且精确对准的。这种新的集成方法为光学拾取头提供了一种简单且低成本的制造方法，消除了手动组装的需要。
This paper proposes a novel method for integrating inclined mirrors with precise angles and smooth surfaces in on-chip Fresnel lens optical pick-up-head applications. A glycerol-compensated inclined-exposure technology was adopted for 45degrees mirror pair fabrication. This technology can fabricate 19-90degrees inclined structures onto SU-8 negative tone resist with thickness from 100 to 1000 mum. Glycerol is employed as an index matching material during exposure to compensate for the refractive index difference between the air and SU8, thus extending the possible inclined angles from 54degrees (in air) down to 19degrees (in glycerol). To eliminate reflected induced patterns, CK-6020L resist is employed as an antireflection layer. The surface roughness, measured by AFM, is below 7 nm for various inclined angles. Device fabrication has been successfully completed and test results demonstrated a functional VCSEL (vertical cavity surface emitting laser) beam focusing on a 5 mum spot. Further beam size reduction into the sub-micrometer range requires an objective lens with high numerical aperture, which is not within the scope of this paper. The fabricated optical components are robust and accurately aligned. This new integrated approach provides an easy and low-cost fabrication method for optical pick-up heads eliminating the need for manual assembly.