| 摘要 |
A back light module where one of the top and bottom surfaces of the light guide contain a micro Fresnel lens array which is off-axis so that a portion of the light won't initially escape from the back light module. The light is reflected down the length of the light guide, spreading the light across the back light module. In one embodiment, the Fresnel lens array is designed to have its efficiency vary across the back light. A smaller percentage of the light is directed out of the module near the light source, with most of the light being directed down the light guide. In an LED embodiment, the LED is mounted on the top or bottom edge of the light guide with a diffraction structure on the opposite side to diffract the light down the light guide.
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