[OPTICAL REVIEW Vol. 4, No. 5 (1997) 584-587]

Automatic Alignment of Optical System Using Shape Memory Alloy*

Minoru SASAKI, Yuji ARAI and Kazuhiro HANE

Department of Mechatronics and Precision Engineering, Tohoku University, Sendai, 980-77 Japan

(Received October 3, 1996; Accepted June 27, 1997)

Properties of the shape memory alloy of 29 μm thick Ni-Ti foil are investigated as an actuator to align optical elements. Since the intrinsic properties of the Ni-Ti foil are not satisfactory in reproducibility and hysteresis, a simple feedback control is used. A pinhole integrated with a surrounding position sensor is proposed to realize a confocal optical system having an automatic alignment function. Large displacement (~mm) and precision at the level of the optical wavelength are found to be possible.

Key words : shape memory alloy, Ni-Ti, two way shape memory effect, alignment, pinhole, photodetector, feedback control