[OPTICAL REVIEW Vol. 10, No. 4 (2003) 321-324]
© 2003 The Optical Society of Japan

Effect of Interference on Scanning Performance of fθ Lens Fixed by a Shrink Fitter

Isami NITTA, Akihiro KANNO1 and Kimio KOMATA2

Department of Mechanical and Production Engineering, Faculty of Engineering, Niigata University, 8050 Ikarashi 2, Niigata 950-2181, Japan
1Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2, Niigata 950-2181, Japan
2OPCell Co., Ltd., 1-1-21 Daitakubo, Saitama 336-0936, Japan

(Received January 31, 2003; Accepted May 6, 2003)

An ultra-precise method of joining optical lenses in a housing by a shrinkage fit has been developed using a shrink fitter, which is a cylindrically shaped machine element made of a plastic material. In this method, the form error of the shrink fitter increased the interference of shrinkage fit which caused a lens deformation much greater than the limitation of surface irregularity of λ/2. With an fθ lens unit of the laser scanner, this lens deformation may deteriorate the laser beam spots on an image plane. Therefore, the shrink fitter is carefully and precisely turned, however this takes time and costs money. This is a contact problem between the optical lenses and the shrink fitter. In this paper, to determine limit interferences of the shrink fitter, the effect of the interference of the shrinkage fit on the scanning performance was examined through computer simulation.

Key words: laser scanner, beam spot, fixing element, shrink fitter, interference, lens deformation, surface irregularity, optical analysis