PURPOSE: To provide an ultrasonic actuator with an increased stroke and a small-sized pyroelectric infrared sensor of improved sensitivity.
CONSTITUTION: Piezoelectric elements 12a, 12b are adhered to two perpendicular surfaces of a regular quadrangular prismlike elastic element 11 to constitute a vibrator 10. When alternating electric fields having a phase difference are applied to the elements 12a, 12b, the vibrator 10 is rotatably moved. A moving element 15 is brought into pressure contact with the vibrator 10, and supported movably only in a direction perpendicular to a longitudinal direction of the vibrator 10 by a moving element support 16. An L-shaped displacement increasing member 21 is supported to a rotary node 17 of the element 15, and a base side of the element 15 is engaged with a supporting groove 19 provided at a vibrator holder 13b to constitute a displacement increasing mechanism 20 which utilizes a principle of a lever. A slit 23 is formed on a shielding plate 22 of one side of the member 21, and an infrared ray 25 is repeatedly incident on and shut OFF from an infrared detector 24 by reciprocating movements of the slit 23.
NOMURA KOJI
NISHIKURA TAKAHIRO
KAWASAKI OSAMU
