Fabrication of Light Guide Plate on PDMS-Based Using MEMS Technique for Application of LED-Backlight

Following the development of the thin-LCD, many researchers have improved the traditional backlighting module to make it thinner, lighter, and brighter which has already become the trend. The light guide plate is a very important component in backlighting module. Generally, the traditional light guide plate (LGP) is made of PMMA material. Injection molding technique is applied to fabricate the traditional LGP. In this research, Polydimethylsiloxane (PDMS) material was used to make the LGP, which was fabricated by using MEMS technique. In order to modify the traditional LGP, the micro prisms were constructed on the bottom surface of the PDMS LGP. Silicon mold was used to define the geometry of the micro-prism. Anisotropic etching technique was applied to fabricate the prism silicon mold. A liquid PDMS mixture was cast onto the prism silicon mold and the PDMS LGP was completed. White LED was utilized to be the light source of the PDMS LGP. After going through the illuminative test, PDMS LGP was demonstrated successfully of guide light function and its 77% of illuminative uniformity was achieved requirement of a general v-grooved light guide. The thickness of the PDMS LGP is easy to control and the PDMS is a heat-resistant and cheap material; therefore, the space and fabrication cost are saved. The field of MEMS has experienced rapid growth in the recent decade. In the future, the PDMS LGP can make displays thinner and brighter for thin-LCD applications.