||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% .
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