Design Optimization and Sensitivity Analysis of Manufacturing Errors for LED Edge-lit Integrated Light Guide Plates

[[abstract]]本研究運用新型的薄板模仁製程，以SOI矽基板結合非等向化學濕蝕刻配合電鑄製程製作的非印刷式導光板，並利用SOI矽晶圓在[111]面蝕刻停止的特性，可製作出高精準的截頂角錐，控制微結構另其旋轉45度成菱形結構分佈於側光式導光板的底面，並搭配導光板入光側頂角90度稜鏡結構以達到所需之軸向集光效果。本研究以TracePro光學軟體進行所設計之微特徵分佈的光照度、強度模擬。將導光板作區塊劃分規劃後作為特徵分佈之變數設計，並以正弦波及線性形式控制微特徵在導光板上的位置分佈，並依據照度結果以模糊理論作參數最佳化調整。最後依據實際射出之導光板成品，討論導光板因製程而可能產生如結構尺寸、導光板厚度、特徵高度等誤差對於導光板光學特性的影響。針對所產生的影響提出改善，其改變方式則依據輝度模擬結果，使用模糊理論進行最佳化參數搜尋;亦改變導光板間區塊劃分方式、導光板排列方式等，依循實際產出所發現的缺失部份進行改善，進而得到均勻化之輝度結果。[[abstract]]This study applies a novel fabrication process of molding stamper that combines anisotropic wet etching of silicon-on-insulator (SOI) wafers with electroforming for the molding of non-printed light guides. Because the geometry of the fabricated feature of SOI using anisotropic wet etching is defined by [111] crystal planes and the etch stop, micro truncated pyramids with high dimensional accuracy and surface characteristics can be fabricated. The truncated square pyramidal features are orientated 45 to the light of travel by mask design, which in combination with the 90° prisms on the light inlet surface of the LED edge-lit LGP provides an enhanced axial luminance intensity which is similar to the use of conventional two orthogonal prism sheets. A light tracing program, TracePro is applied to simulate the light intensity, illuminance, and luminance for a distribution of micro features. LGP is divided into smaller regions. The feature spacing of each region is adjusted by a fuzzy optimization scheme. A sinusoidal modulation of feature distribution is also introduced the fuzzy theory for optimal adjustment parameters according to simulated result. We analyze the sensitivities of the optical properties to possible manufacturing errors such as the dimensions of the micro features and the thickness of LGP.A modified distribution pattern is proposed according to the experiment result. The optimum result after fuzzy optimization search provides LGP design with much improved uniformity