Solution for warpage in the liquid crystal display module process

We propose a module technology that solves the problem of warpage, which cause bending of the substrate in liquid crystal displays (LCDs). The characteristics and behavior of cell-gap and glass warpage under thermal energy were observed, and the effects of glass warpage were investigated. It was found that applied heat in the compression process in the case of the chip-on-glass (CPG) technique decreased the uniformity of the cell-gap. We showed that deterioration of the cell-gap caused glass warpage under the high temperature of the compression process. Thus, a preheating substrate treatment was carried out before compression as a solution to glass warpage. A contact surface illuminometer was employed to measure the bending of the substrate. As a result, the glass warpage was decreased and a uniform cell-gap was obtained.