COLOR FILTERS WITH NEGATIVE BIREFRINGENCE FOR LIQUID-CRYSTAL DISPLAY USE

We have developed a special color film with negative birefringence, wh ich can work as a color filter and a viewing angle extension film for liquid crystal displays (LCDs). A high-performance polyimide (PI), whi ch can be dissolved in the usual organic solvent and shows negative bi refringence after lamination, was synthesized to fabricate the film. B y mixing PI with suitable proportions of green, blue or red pigment in the solvent, then laminating them onto a glass substrate, we obtained color films with good transmission spectra and suitable chromatic coo rdinates. The results of our experiments show that the color filters s till have negative birefringence but a little lower than that of the p ure PI film. and can therefore work as compensation films for normal w hite twist nematic liquid crystal displays (TN-LCD).