Dein SHAW and Chih-Wei LIN^*

Department of Power Mechanical Engineering, National Tsing-Hua University, #101 Kung Fu Rd. Sec. II, PME, NTHU, Hsinchu, Taiwan 300, R.O.C.

(Received July 11, 2008; Accepted December 27, 2008)

The purpose of this study was to analyze the coma compensation of bi-convex o-ring driven liquid-filled lenses. In a previous study, the o-ring driven liquid-filled lens was composed of a base plate, a glass covered liquid container, an elastic membrane, an o-ring, a spring, and three hand-driven screws. The movement of the ring is used to control the focal length or the focus position. However, the o-ring driven liquid lens exhibited a coma effect when trying to use it to tilt the direction of light. To resolve this problem, in this study the bi-convex o-ring driven liquid-filled lens was constructed of two single o-ring driven liquid-filled lenses, and a coma compensation analysis of this new design is carried out. ZEMAX software was used to construct the model, and the Zernike polynomials were used to estimate the compensation result. According to the simulation results, the following two actions could compensate for the initial coma aberration: (1) the same tilt direction of the front and back lenses; (2) increased the curvature of the back lens.

Key words: bi-convex, coma compensation, liquid-filled lens

^*E-mail address: chihwei@webmail.pme.nthu.edu.tw