複合微光學與繞射相位元件用於平面顯示器,波長解多工光譜讀取系統之研究器與藍紫光雷射讀取系統之研究

Abstract

本論文以微/奈結構之繞射光學元件為主軸，結合先進製造技術，達到整合多種功能於一體之高效能創新目標，以突破若干技術瓶頸。本論文，主要分為三大部分： 第一部分，運用純量繞射理論與共軛梯度法建立計算模型與架構，設計超長焦深、高數值孔徑之三波長繞射物鏡用於藍紫光雷射讀寫系統。為了研究此理論，我們提出了數值孔徑在無繞射光束下的定義方式，以對應到幾何光學上之焦深理論，因此，成功地完成兩類元件的應用研究與驗證，包括晶圓級薄膜型雙波長超長焦深、高數值孔徑之繞射相位元件與應用於三波長Blue_ray Disc/ DVD/ CD系統的三波長超長焦深、高數值孔徑之繞射相位元件，相較於新近文獻上使用複雜系統，我們的結果也優於藍光DVD白皮書上之技術規格。 第二部分，運用向量繞射理論與凹面光柵理論進行研究波長解多工光譜器上之計算與元件製作，包括凹面分色光柵元件之計算理論分析，側壁光柵晶片製作，波長分波品質檢測。本論文克服兩個關鍵性技術，成功地開發設計出凹面型微光柵元件之計算瓶頸與高品質ICP側壁鏡面製程技術包括有應用於光通訊DWDM之81通道，頻寬約為0.181nm，頻道間距優於0.39nm與應用於生醫晶片之可見光波段：380nm∼780nm，解析度約為0.18 nm ~0.40nm，頻道間距約為1nm等關鍵技術並具備側壁垂直度< 90±1°與側壁平均粗糙度< 5nm。 最後，運用非成像光學追跡法與向量繞射理論進行計算複合式微結構與光柵元件之平面顯示器無染料式彩色濾光模組，試圖解決現今的TFT液晶顯示器技術與產業自光阻型彩色濾光片發明近三十年來一直無法有效解決液晶面板之整體光能量使用率不只有約5%的問題。本論文運用複合式微結構與繞射光柵等創新式計算與製程驗證，其中包括分色光柵、分束複合自由曲面微結構柱狀鏡之理論計算分析，膜片製作成形與檢測驗證，色彩NTSC演色性測量。已經成功地將傳統液晶顯示器的能源損耗，有效地提升2.2倍的出光效率，足以證明可以將染料式彩色濾光片完整地取代，並達到下世代綠能顯示技術之目標。

Diffractive optical elements with micro/nano structures have been employed as the main methods for the Blu_ray Disc, wavelength demultiplexers, mocro-spectrometer and dye-less color filters; and combine the advanced manufacturing technologies to reach the innovative goal that is expected to be achieved high efficiency by the integration of many functions, in order to overcome several technological hurdles. This dissertation is divided into three major sections. In the first section, the design of a triple-wavelength diffractive objective lens with an ultralong depth of focus and large numerical aperture is described; the lens can be used in the pickup system of a Blu-ray Disc. In this design, the scalar diffraction theory and the conjugate gradient method are used to design the optimization structure of the lens. In order to study the scalar diffraction theory, we propose a new definition for the numerical aperture that is based on the theory of diffractionless beams; this definition corresponds to the definition of the numerical aperture that is based on the theory of focus depth used in geometric optics. Therefore, two types of diffractive optical elements have been studied and their fabrication processes have been demonstrated successfully; these elements are the wafer-level membrane-based dual-wavelength and polycarbonate-based triple-wavelength diffractive phase elements that have high numerical aperture and ultralong depth of focus. These elements can be applied to the optical pickup system of a Blu-ray Disc/DVD/CD. In the second section, the vector diffraction theory and the theory of concave gratings are used to design the optical elements used in wavelength demultiplexers and microspectrometers, including the theoretical analysis and manufacture process of concave gratings based on color division. A device that can be used for wavelength-division demultiplexing of fiber communication and comprises 81 channels has been fabricated; the device has a channel resolution of approximately 0.181 nm and a channel spacing of less than 0.39 nm. This micro-concave grating for wavelength demultiplexers was fabricated using an advanced silicon etching technique; the grating has a high-quality mirror-like sidewall perpendicularity of 90 ± 1° and an average surface roughness of less than 5 nm. In addition, a micro-concave grating operating in the visible wavelength range of 380–780 nm with a resolution of 0.18–0.40 nm and a channel spacing of approximately 1 nm that can be used for biomedical applications is also presented. In the final section, the non-imaging ray-tracing method and the vector diffraction theory are used to design a hybrid grating module for dye-less color filters used in flat panel displays. The percentage of the entire amount of light energy that is utilized in TFT liquid crystal displays is only approximately 5% because of the use of dye/photoresist-based color filters. We attempt to solve this problem by using dye-less color filters. In this design, an innovative calculation and fabrication process verification of a hybrid microstructure and the diffraction grating are obtained; the design includes the theoretical analysis for the calculation of optical films with RGB color separation grating and optical films of hybrid cylindrical lens with freeform microstructure for TFT sub pixels beam splitting. The energy consumption of traditional liquid crystal displays has already been improved successfully, and the efficiency of light output has been increased by 2.2 times. These results satisfactorily confirm that the use of dye-based color filters can be eliminated completely and that next-generation display panels based on green energy can be fabricated.