Laser-marking process for liquid-crystal display light guide panel

Abstract A light guide panel is an element of the liquid-crystal display backlight unit, which is extensively used for display devices. In this study, a laser-marking process is applied to the fabrication of light guide panels, and the new fabrication process may replace existing manufacturing methods such as silk screen printing, stamping, or V-cutting methods. The objective of this research is to evaluate the feasibility of the laser patterning system. A series of light guide patterns were made with a 50 W CO2 laser (continuous wave) to understand the effects of laser power and scanning speed on the geometry of groove patterns. The width and depth of the fabricated grooves increased with increasing laser power and decreasing scanning speed. In order to analyse surface geometry, scanning electron microscopy (SEM) photography was used and, for luminance measurement, a Topcon-BM7 was used. As a result, the marking conditions of the laser patterning, 5W and 0.4m/s, were suggested.