Ryoichi KUWANO, Tsuyoshi TOKUNAGA¹, Yukitoshi OTANI and Norihiro UMEDA

Department of Mechanical System Engineering Faculty of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho, Koganei, Tokyo 184-8588, Japan
¹Precision Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016, Japan

(Received May 31, 2005; Accepted June 29, 2005; Revised June 27, 2005)

A liquid pressure varifocus lens that consists of a thin polymer film and liquid is described. The lens can be continuously changed from a concave to a convex shape by driving the liquid pressure in the lens. The dynamic range of the focal length of the convex lens is from 50 to 250 mm. A beam spot verifies the variable focal function on a photographic film exposed by a He–Ne laser. In addition, the application of the laser for processing is demonstrated to manufacture Fe compressed powder sheets by normal pulse YAG laser. Its melting marks along a focus change are formed with a minimum width of 0.1 mm.

Key words: varifocus lens, liquid pressure, focal length, polymer film, YAG laser processing