投影顯示系統中PBS接著後殘留應力之研究

Abstract

隨著光學工業及光電科技的發展，各式各樣的光學元件與光電系統依不同的需求孕育而生，而光學鏡片即為各種光學系統中不可或缺的零組件之一。一般光學玻璃材料的光學性質要求項目：折射係數、色散率、透光性、Abbe 數、內應力、均質性。除了材質本身的因素，在使用加工過程也會對鏡片品質造成影響，都無可避免的使材料本身產生暫時性應力及殘留應力。這些應力變質層的存在會破壞材料的均質性，進而使鏡片的光學性質發生變化，造成鏡片之雙折射現象而影響到成像的品質，對要求高精度的光學系統而言，應儘可能讓此影響品質之因素降至最低。 本研究首先運用光譜儀量測黏著UV膠的偏振分光器(PBS)，在一溫度梯度場中通過PBS的偏振光，其穿透率變化程度；另外並建立一組內含PBS的LCoS光學系統進行實驗，檢視因溫度分佈不均勻造成之雙折射效應；將投影畫面亮度均勻度分佈對應至PBS偏振光的穿透率變化結果，可求得PBS黏著UV膠在不同的位置與使用不同硬度UV膠的雙折射效應；上述實驗結果顯示，運用本研究建立之模型，可在產品設計初期即可先得知，PBS在黏著製程因殘留應力造成的暗場漏光與顏色不均勻的狀態，加以合理的改善對策，提高光機產能及改善色彩品質。

Coming with the developing electro-optic technology and continuously growing optics industry, ranges of optical devices and electro-optic systems have been built to fulfill varieties of market needs. Optical lens plays a crucially role amongst all of the indispensable components to these applications. Refractive Index, Dispersion, Transmittance, Abbe Number, Internal Stress and Homogeneity are the most well-known key factors that dominated the optical characters of lens. However, besides the factors of material consistence, Temperatory Stresses and Residual Stresses generated through manufacture process would also impact the quality of lens. The existence of the stress would damage the homogeneity of glass and gradually change the optical characters of the lens. These changes would cause the pheromone of Birefringence which impacts the quality of image. For the high precision optical system, the elimination of the birefringence is essential. In this thesis, a spectrometer is used to measure the transmittance spectra when polarized light passes through the PBS covered with UV glue under a designed temperature gradient field. At the same time, a LCoS optical system with PBS is constructed to examine the state of birefringence due to the non-uniformity temperature. Comparing the brightness uniformity of projection and the changes of transmittance of polarized light, the birefringence effect can be found with factors, the location of UV glue on the PBS and hardness of UV glue. Above-mentioned experiment shows, using the model in this study, the defects of light leakage in a dark field and non-uniformity of color caused by residue of stresses from curing process in PBS can be examined at the very beginning of design phase. With proper and effective solutions, production capacity and color quality can be improved.