| 摘要 |
PROBLEM TO BE SOLVED: To reduce frictional resistance acting between the bush part of a guiding shaft for guiding a moving lens frame and the lens moving frame and a rotation regulating guiding hole part by providing an electromechanical energy conversion means vibrated in parallel with the shaft direction of the guiding shaft at one end of the guiding shaft. SOLUTION: The moving lens frame 123 holds a 2nd lens group L12 movably along an optical axis O. The bush part 123a slidably engaged with the guiding shaft 121 is provided on the upper side of the frame 123 and the rotation regulating guiding hole part 123b slidable with the guiding shaft 122 is provided on the lower side thereof. Ceramic piezoelectric elements 201 and 202 are attached to the ends of the shafts 121 and 122 so that their resonance direction may be aligned with the shaft direction of the shafts 121 and 122. By impressing an alternating current having resonance frequency on the elements 201 and 202, the elements 201 and 202 are elongated and contracted in the resonance direction with the resonance frequency and the shafts 121 and 122 are vibrated in the shaft direction. |
