具電控可調式液態透鏡應用在光學同調光斷層掃描術

AN ELECTRICALLY TUNABLE ASYMMETRICAL LIQUID LENS SYSTEM FOR OPTICAL COHERENT TOMOGRAPHY

胡柏偉

液態透鏡 ； 光學同調光斷層掃描術 ； 介電泳 ； Liquid lens ； Optical Coherent Tomography ； Dielectrophoresis

清華大學工程與系統科學系學位論文

2016年

碩士

曾繁根;王本誠

繁體中文

本文探討使用介電泳式（Dielectrophoresis, DEP）驅動液態透鏡的設計與製作，操縱微米等級的液珠在玻璃晶片上作不規則形變，改變曲率半徑使其具有同時變焦及折射光線的能力，透過電控液態透鏡來改變焦距或是偏折光線，進一步取代傳統光學同調光斷層掃描術中的旋轉鏡組合聚焦鏡組，以達到縮小光學同調光斷層掃描術前端設備尺寸的目的。 本研究以耐熱玻璃當做基材，經由微機電製程（MEMS）製作出具有不相連多個不相連電極環繞在液態透鏡的周邊，對稱的電極可以施予驅動電壓，使液態透鏡進行變焦和偏折，達到和傳統固態透鏡系統相同之效果，以此來結合同調光斷層掃描術重建組織三維影像並大大縮小整體前端系統尺寸，微米級液珠利用DEP來驅動液珠產生不規則形變，藉由給予不同的高頻驅動電壓，來觀察液珠表面接觸角變化和光線偏折能力並藉由此晶片去取代光學同調光斷層掃描術之前段設備。本文探討以不同的高頻驅動電壓來觀測微小液珠的接觸角變化，以及光線曲折的能力，實驗結果顯示:(1)液珠的接觸角隨著電壓的增大，會有遞減的趨勢變化，亦即如果未超過其液珠的頻率響應值，電壓增大角度變化亦遞增；(2)經由實驗得知，液珠在其輸入頻率為5K Hz時有著對此液珠的驅動最大效果，可以使接觸角變化約20°；(3)不同波形對液珠的影響亦不相同；(4)液珠在驅動後可以有效的將光線曲折約4.76°，在其驅動最佳條件下。此研究不僅經實驗證實微米級液珠在晶片上可以具備有變焦和曲折光線的能力，更配合實驗的結果印證，找出其驅動的最佳參數，能有效的降低驅動電壓的需求。此一技術進一步可以應用結合同調光斷層掃描術，能夠廣泛應用在生醫成像術和癌症早期檢測上頭。

This paper reports a novel design of an electrically tunable asymmetrical liquid lens that can deflects optical beam by controlling the lens curvature through driving voltages, which can be integrated with axicon prisms for Optical coherent tomography (OCT) application. Conventionally, clinical verification of cancer tumors routinely depends on biopsying a small piece of tissues for microscopy investigation, however, this is not only a invasive process but also confronted with some risks of the taken tissues containing no cancer cells. To improve the accuracy of diagnosis and reduce patient burden on invasive biopsy, low-invasive OCT system has been proposed to replace the traditionally way in cancer diagnosis. Currently most of the OCT systems employing rotational or vibrational solid lens incorporated with prism system for obtaining three dimensional scanning of surrounding tissues for diagnosis, however, the scanning speed and the convenience to use the system in a curved vessel is greatly limited by the solid mechanism design. For this purpose, we propose the application of a morphology tunable liquid lens integrated with an axicon prism to circumvent the aforementioned problems. This abstract reports the preliminary result of the manipulation of the liquid lens for the basic functions of light beam deflecting/scanning under various electrical energy applications on one side of the lens. The property of the lens for light deflection can be accomplished using non-uniform driving voltages on different electrodes to manipulate the surface morphology of a hemi-spherical liquid lens into a ramp-shaped lens (RSL). A spot light shift of 0.9 cm (scanning angle of 4.76°) on a paper screen by actuating a 500 μm liquid lens at 109.7 volts and 5KHz on one electrode of the six was successfully demonstrated, while the lens one-side contact angle varied from 85° to 65° accordingly. As shown before we demonstrating the functionality of the focal length charging and the laser beam deflecting. The scanning speed and focused spot can approach 10k Hz and 150μm, respectively, which are suitable for OCT application.

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