Abstract: The injectioncompressing and injection moldings of aspherical plastic lens were analyzed and compared. The injectioncompression molding required smaller injection pressure and clamping force. The stress in the melt was uniform and smaller cavitation and weld line, better appearance, and smaller birefringence were obtained on the products. For the injection molding, the hysteresis and phase shift in Z direction were larger, which caused polarization in the products, resulting in worse quality of optical elements.

Key words: aspheric surface, injection compression molding, refractive index, polarization, phase shift, hysteresis