光斑抑制之雷射光源及其應用

Speckle-suppression of laser source and its applications

塗時雨(Shih-Yu Tu)

指導教授 ： 林晃巖

國立臺灣大學/電機資訊學院/光電工程學研究所/博士(2015年)

https://doi.org/10.6342/NTU.2015.11238

摘要

近年來，由於雷射於顯示器與照明裝置應用愈來愈多，使得雷射光斑已漸漸成為一重要的研究課題。本論文主要在發展光斑抑制的雷射光源與探討其可能的應用，主要包括照明、顯示與影像等應用，亦包括生物與軍事等等領域。本論文希望對雷射光斑之產生與抑制進行探索，並發展光斑量測之系統與方法，同時發展有效率、簡單易用的雷射光斑抑制技術及方法，進而對這些光斑抑制方法做分析與比較。
第一章給予雷射光斑抑制的基本簡介，包括雷射光斑抑制的方法與應用。光斑抑制雷射於照明領域與2D、3D顯示領域中。光斑抑制雷射應用於其他領域，可包括生物科技、醫療、列印、光蝕刻、軍事等諸多應用。
第二章主要探討光斑的產生與抑制理論，並發展微擺動、混光、重疊與多投影單元等光斑抑制技術及其模型的建構。
第三章主要探討本論文所使用的光斑對比量測技術。藉由參考Goodman與其他學者所發展的相關光斑量測技術，我們能夠架構雷射光斑對比量測系統、定義光斑對比值與計算光斑對比值，可量測範圍為SC=3%至~100%之光斑量測系統，並用於光斑抑制技術的量測與開發。
第四章主要探討時間依賴與時間獨立光斑抑制技術應用於靜態雷射光束。藉由音圈馬達的擺動模式，我們將屏幕、螢光粉紙、擴散膜元件裝置於擺動元件上，已達到有效的光斑抑制成果。其中，微擺動技術、混光技術為相當有效、精巧、易於製作之光斑抑制方法。在對人眼一倍的影像尺寸下，可獲得無光斑結果。
第五章主要探討時間依賴與時間獨立光斑抑制技術應用於微機電掃描式雷射光束區塊。藉由微擺動技術、混光技術、重疊法、多投影單元法等光斑抑制技術，我們可以獲得有效的光斑抑制結果。採用一種以上的光斑抑制技術，在對人眼一倍的影像尺寸下，可獲得無光斑結果。
第六章為結論與未來展望。希望能藉由本論文的研究與討論，促進雷射於照明、顯示、影像及其他應用的發展。以期待光斑抑制雷射光源能對科學、教育、生活、醫療、軍事等用途上有所貢獻。

關鍵字

雷射 ； 光斑 ； 擴散膜 ； 微結構 ； 奈米結構 ； 投影機 ； 顯示 ； 照明 ； 微機電 ； 掃描

並列摘要

Since the invention of the laser in 1960, laser coherence has been at the forefront of many research ventures. When a rough surface is illuminated by a coherent laser beam, speckle patterns are generated. In recent years, lasers have been used in an increasing number of display and illumination devices. Speckle has the effect of causing harsh illumination, noisy images, and low contrast, and is an issue that must be solved at the early stage of development. In this dissertation, speckle suppression in laser sources and its applications to the fields such as illumination, display, imaging, biotechnology, and military applications, are explored and researched. The main discussion is on speckle generation and suppression, development of a speckle contrast measurement system, and the development of simple, efficient, and compact speckle reduction techniques. Furthermore, a comparison and analysis will be made for the speckle suppressing methods.
Laser speckle suppression is introduced in Chapter 1, which discusses suppression methods and applications. These methods could be applied for illumination and display applications.
In Chapter 2, speckle generation and suppression is discussed. Micro-vibration, mixing, overlapping, and multi-unit projection techniques are developed and expected to contribute to science, education, and our daily lives.
In Chapter 3, speckle contrast measurement technologies are discussed and referenced from Goodman and other scholars. We could construct our own laser speckle contrast measurement system and define the speckle contrast (SC) and mixing speckle contrast (MSC). SC is calculated and applied in the development and measurement of our speckle suppression technologies. The measured SC can be ranged from 3% to ~100%.
In Chapter 4, time-dependent and time-independent speckle suppression techniques are applied on a static laser beam. By vibrating modes of voice coil motors (VCM), the screen, phosphor and diffuser papers are used on the vibrating VCM device to achieve efficient speckle reduction results. Among them, the micro-vibration and mixing are very efficient, compact, and easy-to-use speckle suppression methods. Under 1x image size for human eyes, the speckle free results can be achieved.
In Chapter 5, the time-dependent and time-independent speckle suppressed techniques are applied on a MEMS scanning laser beam area. By micro-vibration, mixing, overlapping, and multi-projection, efficient speckle suppression results can be achieved. Under 1x image size for human eyes, using more than one technique, the speckle free results can be achieved.
Finally, the conclusion and future works are shown in Chapter 6. We expect that, through the study and discussion in this dissertation, we will be able to promote laser development for future use in illumination, display, imaging, and other applications. In the meanwhile, we expect the developed speckle suppressed light source can make the contribution on science, education, human life, bio-medicine, military and so forth.

並列關鍵字

Laser ； speckle ； diffuser ； microstructure ； nanostructure ； projector ； display ； illumination ； MEMS ； DLP ； LCoS ； scanning

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