液體充填式透鏡與可撓性感測膜之光學模組之研究

A study of Optical Module which Consists of a Liquid-Filled Lens and a Flexible Sensor Membrane

郭詩坪(Cuo, S. P.)

指導教授 ： 蕭德瑛

國立清華大學/工學院/動力機械工程學系/博士(2011年)

https://doi.org/10.6843/NTHU.2011.00407

摘要

影像感測元件以硬質的平面感測元件為主，而單一透鏡最佳成像面為曲面，以致感測平面與最佳成像面間產生成像位置誤差，造成單鏡片光學系統離軸影像品質不佳，因此需要以多片透鏡組來修正光學像差而使整體光學模組體積無法縮小等問題；為改善上述問題而啟發了有關可撓性透鏡與感測元件研究的動機；先前的研究已依序完成了液體充填式透鏡原型模組，探討重力、流道數量、壓力等條件對液態薄膜形狀及成像品質影響，也對液體充填式透鏡變焦效果進行分析。本研究經由人類視覺系統架構的觸發，針對液體充填式透鏡配合撓性影像感測薄膜做整體分析，研究液態透鏡與感測薄膜相關參數、受液壓力後曲率變化及兩者間於光學特性之相互補償關係。另配合光學透鏡的光學特徵，研究撓性影像感測薄膜最佳參數，使可撓性影像感測薄膜受液體壓力變化後的曲率配合液態透鏡最佳成像面；研究分析重點包括液態薄膜透鏡受液體壓力後光學性質推導，液態透鏡在特定條件下的變形曲線方程及其最佳成像面，分析撓性影像感測薄膜於不同條件下曲率的變化，並控制其直徑、厚度及楊氏系數使撓性影像感測薄膜變形曲線與最佳成像面相符的最佳參數以及液態透鏡與撓性影像感測薄膜之整合設計使光學模組於不同內壓力條件下具有自動光學補償作用，而獲得清晰的影像。可撓性感測膜是在可撓性薄膜基材上設有影像感測晶片，並利用半導體打晶線製程技術將各個晶片相連結而形成可撓性光學感測元件。在單一鏡片條件下比較固態平面感測器與可撓性感測膜所得到的影像品質，可撓性影像感測膜相較於平面感測元件有較佳之 MTF，較小的光學像差及較寬廣的視角，研究技術將可應用於電子數位照相機外接鏡頭系統、可拋棄式醫療檢視器材、監視器光學專業領域及自動補償的光學系統。

關鍵字

液體充填式透鏡 ； 可撓性感測膜 ； 光學模組 ； 場曲 ； 自我補償 ； 聚二甲基矽氧烷

並列摘要

Most image sensors are flat and made by hard material, but the focal surface of a single lens system is a curvy surface. There are gaps between the flat sensor surface and the focal surface. The flat shape image sensor brings the problem of aberration of off-axial image when the image through a lens, because of the error gaps between of focal surface and flat sensor. One needs multiple individual lenses for aberration correction, that cause the lens module cannot be compact. For resolving the above issues, it motives the study of liquid lens and flexible sensor system. The previous researches include mockup sample of liquid-filled lens optical module, studies of image effects of gravity, number of flow channel, liquid pressure and zoom function. This research is guided by human eyes structure, based on a simple structure of a liquid-filled lens and a flexible sensor membrane to process the optical module analysis. The research focused on the deformation of liquid- filled lens and sensor membrane, optical characters and the relation of optical compensation. The optical integrated module has compensation function between lens and sensor membrane, and obtains a clear image under different internal pressure. For matching the optical characters of lens, required shape variations of flexible image sensors were studied. The critical parameters include diameter, thickness, Young’s modulus of membrane, and internal pressure of lens chamber. The flexible sensor membrane installs image sensor chips on flexible membrane substrate, and applied wire bounding technology to group all chips together. For a single lens optical system, the curvy sensor membrane has better performance than flat type sensor in the image quality of MTF, aberration and angle of view. The research can be applied in the fields of the adapter lens system of digital camera, disposal medical optical accessory, security optical devices and self-compensation optical system, etc.

並列關鍵字

liquid-filled lens ； flexible Sensor Membrane ； optical module ； field of curvature ； self-compensation ； Polydimethylsiloxane (PDMS)

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