直下式背光模組最佳化之設計

The Optimization of Design for Direct-Light-type Backlight Module

呂理銘(Lea-Ming Lu)

指導教授 ： 陳奇夆

國立中央大學/工學院/光機電工程研究所/碩士(2006年)

摘要

在直下式背光模組中，因為燈管直接置放於面板後面容易看出明暗條紋，故均齊度是件重要的考量。通常用光線追跡之商用套裝軟體來模擬於何種情況下有最好的均齊度；但是其軟體模擬非常費時，又無優化功能，無法滿足快速模擬設計研發的需求。所以本研究目的為自建一程式，其光線能簡易快速在燈箱追跡模擬，以及統計光強度分佈，優化所有燈箱參數之結果，找出最佳的均齊度，並用光學軟體比對驗證。將可大幅縮短模擬與優化時程；在相同條件下，自建程式模擬的平均時間約為光學軟體的 倍。於此優化20吋4:3面板、8支燈管，厚度各別為4 cm與2.5cm之模組，其最佳均一性分別為90%與89%；32吋與37吋16:9面板，厚度2.5cm，燈管數目分別為10支與12支之模組，其最佳均一性分別為87%與91%。其優化之結果將可以減少擴散板與擴散膜之成本。
除了均齊度之外，光使用效率在背光模組也是很重要的考量，在此將直下式背光模組底部反射板改變構造，在每支燈管之間添加三角形的反射物，使光線經由三角反射物反射後，其角度與法線之夾角變小，進而導正光線的方向。將光線在三角反射物模組之追跡情形與統計強度分佈到優化功能建立於程式中，以縮短模擬時程，同時對均齊度與光使用效率做優化，並與光學軟體做比對驗證，進而減少稜鏡片之成本。在此分別優化20吋4:3與32吋16:9面板，厚度2.5cm，燈管數目分別為8支與10支之三角反射物背光模組，加上擴散板後，其最佳出光角度分佈之半強角都在46 ，均齊度也有控制在85%以上。

關鍵字

最佳化 ； 光使用效率 ； 光跡模擬 ； 均齊度 ； 直下式背光模組

並列摘要

In the direct-light-type backlight module, light sources are placed under LCD panel directly that we could see stripes easily. So uniformity is the important property to pay attention. The common method is using optical ray-tracing of business software to simulate in what condition that we could get best uniformity. But using them costs a lot of time and they have no optimum function. It can not satisfy speedy simulation of requirement to design and research. Therefore, the target is point at using self-establish program to show the rays in backlight module for ray-tracing and to gather statistics about distribution of illumination. Finally find the optimal solution of all results of conditions and using optical software to compare and test. Then it could reduce time substantially for simulation and optimization. In the same condition of case, simulation of self-establish program costs average time is optical software times approximately. To simulate 20 4:3 panel, for 8 lamps, both depth of module is 4 cm and 2.5 cm, the optimal uniformity is 90% and 89% respectively. To simulate both 32 and 37 16:9 panel, depth of module is 2.5 cm , number of lamps is 10 and 12, the optimal uniformity is 87% and 91% respectively. The result of optimization would reduce the cost of diffuser.
Besides uniformity, the efficiency of light is also the important property. We change structure of bottom reflector in the backlight module, to add triangular reflect object between lamps. They can decrease rays’ angle with normal, and collimate direction of rays. Then build up program include ray-tracing, distribution of illumination, and optimization to reduce time for simulation. We optimize both uniformity and efficiency of light, and using optical software to test and verify. The result of optimization would reduce the cost of BEF. To simulate both 20 4:3 and 32 16:9 panel, depth is 2.5 cm , both number of lamps is 8 and 10 with triangular reflect object and to add diffuser on module, the optimal distribution of light for half-intensity angle is 46 ,and uniformity is also over 85% .

並列關鍵字

optimization ； efficiency of light ； uniformity ； simulation of ray-tracing ； direct-light-type backlight module

參考文獻

[1]. 光電工業協進會PIDA雜誌，2004/3

[8]. Adiel Abileah, Charles Sherman, M. Cammarata, "Lighting Assembly For A Backlit Electronic Display Including An Integral Image Splitting And Collimating Means", United States Patent 5161041, 1992

in backlighting a liquid crystal display matrix", United States Patent

5253151, 1993

6913378, 2005