| 摘要 |
PURPOSE:To decrease the number of components and to prevent the device from increasing in size, weight, and cost by providing an optical detecting means which detects the motion of a 1st motion member and a 2nd motion member which is so arranged that its holes can be detected together with holes of the 1st motion member. CONSTITUTION:A distance ring 7 (2nd motion member) is provided at an axially adjacent part on the same optical axis 5 with a driving ring (1st motion member) and this distance ring 7 is rotated around the optical axis 5 to drive a lens part in the axial direction of the optical axis 5. Then when the lens part is put focusing operation, the driving ring 6 and distance ring 7 are driven integrally and the light projected on the photodetection part 21b of a photocoupler 21 (detecting means) from the projection part 21a passes only holes at the part where holes 7f and 6f are superposed one over the other, thereby outputting a detection pulse. Consequently, the number of the components of the detector is decreased and the device is prevented from increasing in size, weight, and cost. |
