散焦及像散型流體透鏡結合適應性光學系統於驗光儀上之應用

An integrated phoropter combined both defocus and astigmatic lenses with adaptive optics correction

黃介澤(Chieh-Tse Huang)

指導教授 ： 傅尹坤

國立中央大學/工學院/光機電工程研究所/碩士(2014年)

摘要

本論文是關於流體透鏡的光學特性與像差研究，並且結合適應性光學相關應用。本論文研究重點為製作方形流體透鏡並搭配適應性光學系統，此系統的調適特性可有效對於具變焦能力之流體透鏡校正其像差。適應性光學系統的加入可有效地校正像差，雖然會受限於可變形反射鏡的3.5 μm制動範圍，但對於眼科醫學上之應用有很大潛力。另外，散焦及像散型流體透鏡結合適應性光學系統於驗光儀上之應用，我們製作出一流體驗光儀，其包含散焦及像散型流體透鏡。透過流體體積的改變達到校正效果並搭配適應性光學系統，達到改善影像品質之目的。
以流體驅動之流體透鏡補償屈光不正(refractive error) 已被廣泛地應用於眼科醫學上。流體透鏡雖可達到變焦之特性，然而其曲率變化及折射率不均將大幅降低影像品質。實驗中，我們以適應性光學系統補償可調式像散型流體透鏡所產生之波前像差。各個獨立透鏡的光學特性以波前感測器量測。適應性光學系統展示了分別注射三種不同體積下Zernike像差由-0.12, -0.25, -0.32 降低至 0.01, -0.01, -0.20 μm，可調屈光度範圍由0.83至1.84D。此外，結合可調式像散型流體透鏡及搭配適應性光學系統，成功地補償以像散試片產生圓柱軸(cylinder axis) 180°之-1D圓柱屈光度(cylinder power)。
本論文提出一個流體驅動的驗光儀，包含了兩種形式流體透鏡: 一散焦型流體透鏡及兩相交45度之方形流體透鏡，其中的三個透鏡可獨立作動並控制。最後搭配適應性光學系統確認流體驗光儀的光學品質及像差校正能力。我們所展示的流體驗光儀在大小及重量上大幅降低，將更容易應用於眼科醫學上。首先，我們以散焦及像散試片測試流體驗光儀之校正能力，可成功補償 -1.5D圓柱屈光度，圓柱軸30°之試片以及補償形流體透鏡所產生之散焦，最後搭配適應性光學系統，將有效提升影像品質。

關鍵字

流體透鏡 ； 適應性光學 ； 驗光儀

並列摘要

Fluidically controlled lenses which adaptively correct prescribed refractive error without mechanically moving parts are extensively applied in the ophthalmic applications. Capable of variable-focusing properties, however, the associated aberrations due to curvature change and refractive index mismatch can inherently degrade image quality severely. Here we present the experimental study of the aberrations in tunable astigmatic lens and use of adaptive optics to compensate for the wavefront errors. Characterization of the optical properties of the individual lenses is carried out by Shack–Hartmann measurements. Adaptive optics (AO) based scheme is demonstrated for three injected fluidic volumes, resulting in a substantial reduction of the wavefront errors from -0.12, -0.25, -0.32 to 0.01, -0.01, -0.20 μm, respectively, corresponding to the optical power tenability of 0.83 to 1.84D. Furthermore, an integrated optical phoroptor consisting of adjustable astigmatic lenses and AO correction is demonstrated such that an induced refraction error of -1D cylinder at 180° of a trial lens is experimentally corrected.
An integrated phoropter combined both defocus and astigmatic lenses with Adaptive optics correction. A phoropter use to determine refractive error in patients. The phoropter is composed of two lens types: one defocus lens and two astigmatic fluidic lenses that provide sphere power and cylinder power. Each of the lenses is composed of an elastic membrane that is secured with rectangular retaining ring that results in a restraining aperture of 30.0 mm×15.0 mm. Optical power tunability can be achieved via controlled injected fluidic volume, results in a plano-convex or plano-concave lens configuration under uniform pressure. we will focus on aberrations expressed by Zernike polynomials, preferably the term of astigmatism aberration commonly encountered in ophthalmology, to correct wavefront aberrations induced by tunable astigmatic fluidic lens. An integrated optical phoroptor which includes fluidically adjustable astigmatic fluidic lenses and AO correction scheme is constructed. Characterization of the optical properties of the individual lenses as well as AO correction capability is verified by Shack–Hartmann measurements. The trial lens induced refraction error of -1.5D cylinder power at 30°, and the refractive error is corrected by the phoropter. AO based scheme is demonstrated to achieve a substantial reduction of the wavefront errors under 0.2 μm RMS.

並列關鍵字

Fluidic lens ； Adaptive optics ； Deformable mirrors

參考文獻

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