本論文所探討的是如何將直下式背光模組薄型化，透過設計一個側射型整光透鏡，使其包覆在燈管上讓光源能均勻的擴散在背光模組之燈箱空腔中，使燈箱頂部發光均勻進而達到背光模組薄型化之目的，然後設計使用頂角為橢圓的微結構取代傳統擴散板，其目的是將光線向上導正用來均勻化燈管間的條紋光影，使背光模組能保有較佳的均勻度。於此薄型化32吋16:10 8支燈管設計之液晶電視面板，厚度由25mm 降為10mm，其最佳均勻度為84.8%。除了均勻度與厚度外，使用頂角為橢圓角的透鏡結構，用於直下式結構背光模組可減少擴散板與擴散膜使用，進而使背光模組成本降低，亦能保有相當的光學效率。側射型整光透鏡可當作光箱中之支撐結構減少擴散板翹曲所產生之條紋，本論文使用 Trace Pro 光學模擬軟體對液晶電視所要求之均齊度等各項條件進行光學模擬。 In this studying, we plan to realize how to flatten the direct-light-type backlight module. Firstly, in order to improve strips from the direct-light-type backlight module, we design a side emitter lens and shield it on CCFL lamp for having the light spreads in the Backlight unit uniformly. Secondly, for keeping the uniformity and efficiency of light optimization, we design optimized elliptical lens shape to replace the traditional diffuser plate to straighten the light upward for uniformity the Mura shadows between CCFL lamps. To simulate 32 16:10 panel, for 8 lamps, both depth of module is 10mm, the optimal uniformity is 85.4%, It approves that using elliptical lens structures on the plate in the direct-light-type backlight module can not only get the cost down from reducing the thickness of BLU and the use of diffuser plate and diffuser thin, but also have the efficiency of light. The side emitter lens can work as a support in BLU for reducing the Mura from diffuser plate. In this study, we use Trace Pro, the light simulation software, to simulate the uniformity and the related light conditions requested by LCD TV.