Recently, with the increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lens are unable to satisfy the required performance. An aspheric glass lens is fabricated by the high temperature and pressure molding using a tungsten carbide molding core, so precision grinding and coating technology for the molding core surface are required.
This study investigates the effect of diamond-like carbon (DLC) and rhenium-iridium (Re-lr) coating for aspheric molding core surface. The grinding conditions of the tungsten carbide molding core were obtained by design of experiments (DOE) for application in the ultra precision grinding process of the tungsten carbide molding core of the aspheric glass lens used in 5 megapixel, 4×zoom camera phone modules. A tungsten carbide molding core was fabricated under this grinding condition and coated with the DLC and Re-lr coating. By measurements, the effect of DLC and Re-lr coating on the form accuracy and surface roughness of molding coer was evaluated.
