| 摘要: | 本論文是關於非球面透鏡與流體透鏡的光學特性與像差研究。本論文研究重點在(1)製作低成本可變焦非球面透鏡，此透鏡具有顯微放大功能，可應用於顯微觀察領域。再利用變焦機構將非球面透鏡能夠調焦，結合手持式智慧型裝置(智慧型手機或平板)可做為簡單的醫療設備。(2)結合非球面透鏡與流體透鏡製作雙功能流體透鏡，同時具有大範圍調焦及顯微功能。
(1)機械式變焦PDMS非球面透鏡應用在手持式智慧型裝置
有鑑於過去顯微鏡體積龐大，單價昂貴且攜帶不易，並不是所以人都能夠輕易觀察微觀世界。現今手持式智慧型裝置的發展快速，尤其是相機部分。近年來，畫素、感光元件、影像處理引擎等大幅提升，讓手持式裝置相機成像品質越精細。因此我們提出利用聚二甲基矽氧烷（PDMS），再利用重力效應，製造出低成本且成像品質優良的非球面顯微透鏡，該透鏡的成像品質能夠媲美一般顯微鏡。並且經由PDMS溶液劑量的控制，製做出放大率約10至50倍的顯微鏡頭。我們製作出5種不同焦距及放大率的PDMS非球面透鏡(焦距分別為7.0 m m、 7.8 mm、 9.0 mm、 10.0 mm和 10.2mm)。另外設計了具有兩種變型機制的變形機構，藉由變型機構施力於PDMS非球面透鏡上，改變透鏡形狀已改變焦距。最後再與手持式智慧型裝置(智慧型手機或平板)結合成為簡易的醫療設備。
(2)流體透鏡結合非球面透鏡的特性與應用
流體透鏡不需要機械部件即可調整焦距，僅需通過注入液體體積的控制來調焦，我們在一般流體透鏡中加入PDMS非球面透鏡(aspheric PDMS lens, APL)，製作出雙功能流體透鏡，雙功能流體透鏡同時具有大範圍調焦以及顯微功能。雙功能流體透鏡有四種變型調焦模式：(I)顯微模式(APL only)、(II) APL/凹模式(APL/concave mode)、(III) APL/平面模式(APL/plano)及(IV) APL/凸模式(APL/convex mode)。我們分別注入去離子水/乙醇作為控制體積，其調焦範圍分別為12/8mm至 90/65mm[(II)-(IV)]，而在顯微模式(I)時為焦距7.32mm及50倍放大率，並可媲美商業顯微鏡的圖像品質。另外，在(II)-(IV)時，PDMS非球面透鏡可以有效降低像差，使得成像品質更加優良。
;This paper mainly research the optical properties of aspheric lens and fluidic lens.
(1)Mechanically tunable aspheric lenses via additive manufacture of hanging elastomeric droplets for microscopic application
Mechanically deformable lenses with capability of dynamically tuning of focal lengths are presented. The fabricated 5 types of aspheric polydimethylsiloxane (PDMS) lenses present here have an initial focal length 7.0mm, 7.8mm, 9.0mm, 10.0mm, and 10.2mm, respectively. Incorporating two modes of operation in biconvex and concave-convex configurations, the focal lengths can be tuned dynamically as 5.2mm-10.2mm, 5.5mm-9.9mm, 6.6mm-11.9mm, 6.1mm-13.5mm, and 6.6mm-13.5mm respectively. Additive manufacturing is utilized to fabricate 5 types of APLs via sequential layering of materials. Complex structures with three dimensional features and shorter focal lengths can be successfully produced by repeatedly depositing, inverting and curing of controlled volume onto previously cured PDMS droplets. Through our experiments, we empirically find a direct dependence between that the changed in the focal lengths of the lenses and the amount (volume) of deposited droplets. The moldless low cost and flexible lenses fabrication method are able to transform an ordinary commercial smartphone camera into a low-cost portable microscope. A few microscopic features can be readily visualized such as wrinkles of ladybird pupa and printed circuit board. The fabrication technique by successively applying hanging droplet and facile mechanical tuning setup can be easily adopted and mass produce in the development of high performance optical lenses.
(2)A novel dual-function lens with microscopic and vari-focus capability incorporated with an aberration-suppression aspheric lens
Substantial aberrations are ubiquitous in many conventional adaptive lenses due to the existence of deformable interface and thus inevitably compromises the optical performance. In this paper, we introduce a novel concept of dual-function fluidic lenses (DFFL) with a built-in aspheric polydimethylsiloxane lens (APL) to enable the design of a compact optical systems with tunable imaging and aberration suppression properties. This is achieved by varying both hydrostatic pressures (i.e. adjusting the injected liquid volume change) such that a widely tunable focal length and the simultaneously integrated APL for aberrations correction. DFFL can transform to 4 modes: microscopic mode (APL only), APL/concave mode, APL/plano mode, and APL/convex mode. Focal tunability of DFFL from 12/8 mm to about 90/65 mm (DI water/ethanol) is demonstrated without any mechanical moving components. Aberration characterization is carried out systematically and the low cost, high performance microscopic mode can be easily achieved by actuating the contact between APL and PDMS membrane. In addition, DFFL turning to microscopic mode (focal length 7.32 mm and magnification 50X) can rival the images quality of commercial microscopes. |
