虹膜识别镜头的光学设计及生产工艺研究

发布时间：2017-12-31 17:39

本文关键词：虹膜识别镜头的光学设计及生产工艺研究　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着科技飞速发展,智能手机不断更新,传统的身份识别方式已不能满足人们对信息安全的新要求,为此,易用且高可靠的生物识别技术受到人们的高度重视。但在实际应用中发现指纹识别、面部识别等生物识别技术仍存在安全隐患,而虹膜识别技术具有受保护性、高稳定性和高防伪性等独有特点,很好地解决了上述生物识别存在的不足,使其在生物识别界具有很高的研究价值和广泛的应用前景。将虹膜识别技术应用于手机等移动终端是科技迅速发展和人们探索研究的必然。在虹膜识别技术中,虹膜图像的获取是第一步,也是关键一步,它直接影响图像的质量和识别的准确率。本文研究了移动设备上的虹膜图像获取装置,设计了几款虹膜识别镜头,概述了镜头生产工艺,具体内容如下:(1)基于初级像差理论,用PW法求解初始结构,通过分析光学系统参数对虹膜图像质量的影响关系,优化设计了一款大孔径、2P非球面结构虹膜识别镜头。设计结果显示:该系统的F数为1.2,总长为4.1mm,全视场角为32°,工作距离为350 mm-500 mm,经像质评价及公差模拟分析,该镜头像质优良,性价比高,可用于加工生产。(2)采用专利结构缩放法,优化设计一款3P非球面结构虹膜识别镜头,该系统的光学参数如下:F数为2.0,全视场角为32.6°,总长为4.0 mm。当工作距离在300 mm-350 mm之间时,系统的MTF曲线都较好,在1/2奈奎斯特频率处,0-0.8视场的MTF曲线均大于0.4,TV畸变控制在1%以内,相对照度大于87%。与2P结构的虹膜识别镜头相比,该款虹膜识别镜头总长更短,分辨率更高,虹膜识别精准度更高。(3)优化设计一款兼备手机前摄功能的虹膜识别镜头,该镜头F数为2.4,视场角为61.2°,总长为4.45mm。在可见光波段,该系统是手机前摄镜头;而在近红外波段,该系统是虹膜识别镜头。这两种功能由IR切换器实现转换。通过评价不同波段时该系统的像质,既可以满足八百万像素手机镜头的性能要求,又可以满足虹膜识别镜头的性能要求。(4)以3P虹膜识别镜头为实例,介绍了镜片、镜筒及镜头的结构设计要点,完成了3P虹膜识别镜头的初始机械结构设计。用Lighttools软件对结构进行杂光模拟分析,对有效径区域的杂光采用镀膜解决,非有效径区域的杂光通过改变结构解决。(5)简述了镜头的生产工艺。主要包括模具结构设计、注塑成型及镀膜工艺。以设计中所使用的一款塑胶材料为例,完成了基于E48R材料的减反膜系设计,并简要介绍了镀膜生产工艺流程,分析了镀膜参数对镀膜质量的影响。
[Abstract]:With the rapid development of science and technology, intelligent mobile phone constantly updated, traditional identification methods cannot meet the new requirements, the information security for ease of use and high reliable biometric technology has been paid more attention. But the discovery of fingerprint identification in practical application, face recognition and other biometric technology is still unsafe, the iris recognition technology has protected, high stability and high security of such unique characteristics, solves the shortcomings of the biological recognition, which has high research value and broad application prospect in the field of biometric identification. The application of iris recognition technology in mobile phone technology is rapid development and people explore necessity. In iris recognition, iris image acquisition is the first step, but also a key step, it directly affects the quality and accuracy of image recognition. In this paper. The iris image acquisition device on a mobile device, designed several iris recognition camera, the lens production process, the specific contents are as follows: (1) based on the primary aberration theory, the initial structure is solved by PW method, through the analysis of the parameters of the optical system of iris image quality, optimize the design of a large aperture 2P, non spherical lens iris recognition. The results show that the system design of the F number is 1.2, the total length is 4.1mm, the angle is 32 degrees, the working distance is 350 mm-500 mm, the image quality evaluation and tolerance analysis, the lens image quality is good, the price is high, can be used for processing production. (2 using the patent structure) zoom method, optimization design of a 3P structure of the iris recognition of aspheric lens, the optical parameters of the system are as follows: the F number is 2, the full field angle of 32.6 degrees, a total length of 4 mm. when the distance between 300 MM-350 mm, the MTF curve of the system is Well, in the 1/2 Nyquist frequency, the MTF curve of 0-0.8 field are greater than 0.4, TV distortion is controlled within 1%, the relative illumination is more than 87%. and 2P lens iris recognition structure compared to the iris recognition lens length shorter, higher resolution, higher accuracy of iris recognition. (3) the optimization of iris recognition cameras the design of the function of a mobile phone with the lens, the F number is 2.4, the view angle is 61.2 degrees, a total length of 4.45mm. in the visible band, the system is a mobile phone before the shot; and in the near infrared band, the system of iris recognition lens. These two functions by IR. Through the evaluation of different conversion switch the band when the image quality of the system, which can meet the performance requirements of the eight million pixel mobile phone lens, and can meet the performance requirements of iris recognition camera. (4) the 3P iris recognition camera as an example, introduces the structure design of lens, and the lens barrel, end The initial mechanical structure design of 3P lens iris recognition. Using Lighttools software for the structure of stray light analysis, solution to the effective diameter zone of stray light by coating, non effective diameter area of stray light by solving the structural change. (5) the production process of the lens. Mainly includes the structure design of the mould, injection molding and the coating process. In order to design used in a plastic case, complete the antireflection film system design based on E48R material, and briefly introduces the coating production process, analyzes the influence of deposition parameters on the coating quality.

【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP391.41

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