長焦距微透鏡陣列在波前感測器的應用

在適應性光學裡，微透鏡陣列是用來探測和分割入射波前成小部分，將波前集中在Shack-Hartmann 波前感測器上的影像感測器（CMOS）。在這篇論文中，我們呈獻出利用熱回流所製造的各種長焦距（毫米範圍）微透鏡陣列結構的製造方法。為了延長焦距，我們使用聚二甲基矽氧烷覆蓋在我們微透鏡陣列的玻璃基板上。由於聚二甲基矽氧烷和微透鏡陣列界面之間的折射率差異小，因此入射光的折射角度比較小而光線集中在較遠地方。此外，其他特定的焦距可以透過修改折射率的差異。長焦距的微透鏡陣列製造出來後，可以跟影像感測器結合在一起建立成一個 Shack-Hartmann 波前感測器。長焦距的微透鏡陣列在測定每顆透鏡的波前平均坡度可提供更高的靈敏度而波前感測器的空間解析度會因整個探測器之透鏡數目的增加而提高。因此，高的靈敏度和空間解析度使準確性變得更好。實驗結果對系統進行了討論和對長焦距、短焦距以及商業的感測器做比較。

關鍵字

波前感測器；微透鏡陣列；熱回流

並列摘要

In adaptive optics, microlens array (MLA) is used to detect and divide the incidence wavefront into small parts which will be focused on the image sensor (CMOS) of Shack-Hartmann wavefront sensor (SHWS). In this paper, we present the fabrication method of long focal length (millimeter range) MLA with various structure and arrangement based on thermal reflow process. In order to extend the focal length, we used Polydimethysiloxane (PDMS) cover on our glass substrate of MLA. Because of the small refractive index difference between PDMS and MLA interface (UV-resin), the incidence light is less bended and focused in further distance. Besides, other specific focal lengths could be realized by modifying the refractive index difference. After the long-focal-length MLA film was fabricated, it could be integrated with an image sensor to build a SHWS. A longer focal length MLA will provide high sensitivity in determining the average slope across each lenslet under a given wavefront, and the spatial resolution of the wavefront sensor is increased by the number of lenslets across the detector. Thus, the accuracy improves with greater sensitivity and spatial resolution. The experimental result of the system is discussed and compared between the long focal length, the shorter focal length and the commercial SHWS.

並列關鍵字

Shack-Hartmann wavefront sensor ； microlens array ； thermal reflow

參考文獻

[2] J. Liang, B. Grimm, S. Goelz, and J. F. Bille, “Objective Measurement of the Wave Aberrations of the Human Eye with the Use of a Hartmann-Shack Wave-front Sensor,” J. Opt. Soc. Am. A, vol. 11, pp. 1949-1957. (1994)

[3] L. N. Thibos, “Principles of Hartmann-Shack Aberrometry,” Journal of Refractive Surgery, vol. 16, pp. 563-565. (2000)

[4] J. E. Greivenkamp, D. G. Smith, “Graphical Approach to Shack-Hartmann Lenslet Array Design,” Proceedings of SPIE, vol. 47(6), pp. 063601-1 – 063601-4. (2008)

[5] H. Ottevaere, R. Cox, H. P. Herzig, T. Miyashita, K. Naessens, M. Taghizadeh, R. Volkel, H. J. Woo, and H. Thienpont, “Comparing Glass and Plastic Refractive Microlenses Fabricated with Different Technologies,” J. Opt. A: Pure Appl. Opt., vol. 8, pp. 407-429. (2006)

[6] Z. D. Popovic, R. A. Sprague, and G. A. Neville Connell, “Technique for Monolithic Fabrication of Microlens Arrays,” Applied Optics, vol. 27, no. 7, pp. 1281-1284. (1988)

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長焦距微透鏡陣列在波前感測器的應用

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