Share Email Print
cover

Proceedings Paper

Defocus insensitive projection lens for CF-LCOS pico-projector
Author(s): Peng Liu; Qinxiao Liu; Feihong Yu
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Micro-projector has found wide application in the field of mobile phone, pico-projector et al. However, because of the depth of the field of the projection lens, precise focus mechanical design is needed for the optical engineer to get fine and clear image. Wavefront coding technique is a novel technique which is introduced by Dowski and Cathey in 1995. By adding an aspheric phase mask at the pupil of the optical system, wavefront coding technique can make the imaging performance of the optical system insensitive to the defocus, and can also make the system insensitive to the defocus related aberrations, such as spherical aberration, chromatic aberration, field curvature, astigmatism and so on. In this paper, a projection lens with long depth of field for the CF-LCOS projector is developed to satisfy the new requirement. We first design the projection lens with the traditional optical design software to let it project the image to the average projection distance. For example, if the lens is designed with in the range of 0.65-2.0m, then about 1.0m is selected as the preliminary projection distance. After the lens (with a 3mm plane plate at the stop surface) is optimized with the CODE V in this distance, the plane plate is replaced with cubic phase plate. Then the lens is optimized again (the phase plate parameter varied for optimization) to get the final lens. In the new optimization, the resolution should be 3 times of the real resolution according to the LCOS resolution. This new optimized lens has the same MTF or PSF for different fields between 0.65 and 2m projection distances, this ensures the high resolution with no focus operation. Because of the MTF satisfies the LCOS requirement between the distance of 0.65 to 2m, no resolution is damaged and also no focus operation is need in this effective projection distance , thus no mechanical focus system is needed.

Paper Details

Date Published: 15 October 2012
PDF: 6 pages
Proc. SPIE 8420, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical System Technologies for Manufacturing and Testing, 84200V (15 October 2012); doi: 10.1117/12.973647
Show Author Affiliations
Peng Liu, Zhejiang Univ. (China)
Qinxiao Liu, Zhejiang Univ. (China)
Feihong Yu, Zhejiang Univ. (China)


Published in SPIE Proceedings Vol. 8420:
6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical System Technologies for Manufacturing and Testing
Xiangdi Lin; Yoshiharu Namba; Tingwen Xing, Editor(s)

© SPIE. Terms of Use
Back to Top