| 摘要 |
PURPOSE:To simplify the constitution of a mirror driving device, to reduce the cost, and to minimize a bound when a movable mirror is hopped up and down by using an ultrasonic wave motor as a driving source for a movable mirror and driving the movable mirror directly with its output. CONSTITUTION:A stator 11 has a piezoelectric element 11b stuck on the back surface of an elastic ring 11a, a high frequency current is supplied to the piezoelectric element 11b to induce ultrasonic vibrations, by which a surface progressive wave is generated in the elastic ring 11 to rotate a rotor 12. The ultrasonic wave motor 10 is fixed on one side wall 22 of a mirror box 21 and a rotor pin 15 implanted in the rotor 12 penetrates a guide groove 23 formed in the side wall and engages the tip part of the side frame of a mirror support frame 31. The movable mirror is driven directly with the output of the ultrasonic wave motor to eliminate the need for a mechanical member, the constitution may be simple, and the assembling performance is improved, so that the cost is reduced on the whole. |
