Design of a Highly-Efficient Light Guide Plate for the Edge Lighting Backlight Module

Abstract:

This study develops a highly-efficient light-guide plate for edge lighting backlight module that has no optical films. The light guide plate is designed to control the angle of the incident rays to the top surface from light source, to get the highest uniformity of intensity for thin edge lighting backlight system applications. The micro-prisms of pyramidal shape on the top surface can highly-efficient collimate with the light rays. Another micro-prism of v-cut shape on the bottom surface can reflect the incident light into the front direction and mixing the rays in the lightguide plate with the high uniformity. A novel design concept of the v-cut is the regular density varies of the cut in the LGP. The modeling simulation program, employing a Monte Carlo method based on TracePro software, has optimized the shape of the pyramidal micro-prisms on the top surface and the density distribution condition of the v-cut micro-prisms on the bottom surface, also the multiple scattering characteristics. The two types of the micro-prisms at the top and bottom surface can be highly recommended for the uniformity of the brightness via the optimal design process. Future work is warranted on improving the optical efficiency by using light-emitting diodes as a light source. The backlight module will allow us to increase the optical efficiency and to lower the total cost in portable LCD applications. The study confirms that a uniformity of brightness can be achieved without using any optical films, resulting in a high uniformity of 84%.