Patent ID: 10421157

Abstract:
A method of forming an electrode structure for a capacitive touch sensor in a first transparent conductive layer (19) which is located on a first side of a glass substrate (5) on the second side of which is a color filter layer (11,12,13) over-coated with a transparent non-conductive layer (15) and a second transparent conductive layer (7), by a direct write laser scribing process using a pulsed solid state laser (22), the laser wavelength in the range 257 nm to 266 nm and a pulse length in the range 50 fs to 50 ns so grooves (21) are formed in the first transparent conductive layer (19) to electrically isolate areas of the first transparent conductive layer (19) on opposite sides of each groove (21). This selection of wavelength and pulse length enables the grooves (21) to be formed with substantially no damage to the underlying color filter layer (11, 12, 13), the transparent non-conductive layer (15) or the second transparent conductive layer (7) on the second side of the glass substrate (5).