Compound Optical Film Using Gray Scale Mask Embedded with Micro-Voids

Abstract

This study presents a compound optical film to improve luminance and uniformity to apply in side-LED (Light-emitting diode) backlight module. LIGA (Lithographie GalVanoformung Abformung) technology, soft lithography and homemade gray scale mask were combined to fabricate micro-lens array. Optical film with variable size micro-lens array embedded with micro-voids was designed and manufactured. FRED software was used to simulate optical performance. Micro-voids were quantitatively embedded in the PDMS (Polydimethylsiloxane) optical film. Under the quantitative control of air pressure, those micro-voids inside the optical film can cause light diffusion. The compound optical film with embedded micro-voids, multi aspect ratio and variable size micro-lens array can be fabricated quickly without substrate. Luminance Colorimeter BM-7A from TOPCON was used to carry out the optical measurement. According to the measured data, the compound optical film with embedded micro-voids can enhance the luminance up to 5% and the uniformity up to 6.5% ~ 8.4%. The optical efficiency can be improved via the compound optical film.