%0 Journal Article
%T From Spheric to Aspheric Solid Polymer Lenses: A Review
%A Kuo-Yung Hung
%A Po-Jen Hsiao
%A Fang-Gang Tseng
%A Miao-Chin Wei
%J Advances in OptoElectronics
%D 2011
%I Hindawi Publishing Corporation
%R 10.1155/2011/197549
%X This paper presents a new approach in the use of MEMS technology to fabricate micro-optofluidic polymer solid lenses in order to achieve the desired profile, focal length, numerical aperture, and spot size. The resulting polymer solid lenses can be applied in optical data storage systems, imaging systems, and automated optical inspection systems. In order to meet the various needs of different applications, polymer solid lenses may have a spherical or aspherical shape. The method of fabricating polymer solid lenses is different from methods used to fabricate tunable lenses with variable focal length or needing an external control system to change the lens geometry. The current trend in polymer solid lenses is toward the fabrication of microlenses with a high numerical aperture, small clear aperture (<2£żmm), and high transmittance. In this paper we focus on the use of thermal energy and electrostatic force in shaping the lens profile, including both spherical and aspherical lenses. In addition, the paper discusses how to fabricate a lens with a high numerical aperture of 0.6 using MEMS and also compares the optical characteristics of polymer lens materials, including SU-8, Norland Optical Adhesive (NOA), and cyclic olefin copolymer (COC). Finally, new concepts and applications related to micro-optofluidic lenses and polymer materials are also discussed. 1. Introduction Microlens arrays are currently utilized in a wide array of applications, including projection [1], smart phone cameras [2], data storage [3] and imaging devices [4]. Most of the lenses used in these types of applications have a fixed focal length and require precision positioning and high-resolution imaging. Because of this, the size, profile uniformity, numerical aperture, and focal length of microlens arrays are very important factors in relation to system integration. The focuses of optical systems employing fixed-focus lenses are generally accomplished using a servo control system. Solid fixed-focus lens fabrication concepts and methods are quite different from those of microtunable lenses. As a consequence, this paper only compares the fabrication and design methods for fixed-focus spherical and aspherical lenses. The method of fabricating polymer solid lenses is different from methods used to fabricate tunable lenses with variable focal length or needing an external control system to change the lens geometry. A variety of techniques for the fabrication of microlenses already exist. Recently, a variety of fabrication techniques for microlenses have been proposed and demonstrated, such
%U http://www.hindawi.com/journals/aoe/2011/197549/