Analysis on Resolution Enhancement by Optical Pupil Apodization in a Laser Scanning Printing System

Apodization of amplitude and phase at the entrance pupil of an optical system is able to have advantages on optical resolution and focal depth. As an optical system for the electro-photography continuously requires highly resolved dot image and extended focal length to obtain more delicate expression with adequate production stability. Advantages from apodization technique can improve system performance and supply high degree of reliability of the optical system. In this study, theoretical apodization characteristics in a laser scanning optical system for electro-photography is firstly analyzed in the aspects of enhancement of optical resolution and focal depth with the proposed method of apodization. In addition, fundamental experimental result on measurement of beam spot size is reported to support theoretical results.