| 摘要 |
PURPOSE:To regulate undesirable motion while miniaturizing and lightening the whole device, by mounting two plate springs bending in the vertical direction to a lens optical axis at locations where the springs are mutually symmetric to the lens optical axis between a lens holding body and another support body, in an automatic focus adjusting device used for a video-disc regenerative apparatus, etc. CONSTITUTION:A cylindrical holding cylinder 22, to which an objective lens 21 is installed, is made of a magnetic body, and connected to a coil-bobbin 25 by means of two plate springs 23, 24 for tracking, which do not bend in the optical axis direction of the lens and are positioned at locations where the springs are mutually symmetric to an optical axis. Two electromagnets 33, 33' are monted to the inner surfaces of the inner cylinder portions 28 of a magnet in facing shapes, and the holding cylinder 22 moves in the B-B' directions vertical to the optical axis because magnetic force acts on the springs 23, 24 and absorbs the springs when letting currents flow to one electromagnet, and is tracking controlled in response to the magnitude of the currents. Thus, undesirable motion is regulated while the whole device can be miniaturized and lightened because the lens moves only in the tracking direction in a surface vertical to the optical axis. |
