| 摘要 |
PURPOSE:To attain rapid focusing by rotating a lens barrel and moving an image pickup device in the reverse direction to a lens moving direction simultaneously with the movement of a focusing lens. CONSTITUTION:Since the leading direction of a screw face 31 engaged with the focusing lens 4 in the lens barrel 3 is reversed from that of a screw face 32 engaged with the image pickup device 6, the focusing lens 4 and the image pickup device 6 are moved respectively in the reverse directions on an optical axis at the time of rotating the lens barrel 3. When the leading angles of the screw faces 31, 32 are the same, the moving speeds of the lens 4 and the device 6 are the same and their directions are reversed to each other, so that the time required for focusing can be reduced to a half of ordinary time. Thus, rapid focusing can be attained. |
