| 摘要 |
PURPOSE:To drive a lens and to open/close a shutter by one motor and to eliminate the need for a magnet and its driving circuit by disengaging a driving member and a lens driving member from each other through the reversing of a driving member in the middle of rotation. CONSTITUTION:A stepping motor 11 drives the driving member 13 forward from a reference position by the number of steps firstly corresponding to a range finding value, and a lens 17 is moved in an optical-axis direction to perform focusing operation. Thus, the focusing operation is completed and then a pulse motor 11 reverses the driving member 13 by a specific angle to disengage the driving member 13 and a distance cam 14 as a lens driving member from each other and then rotate the driving member 13 again forward to a specific angle position, thereby opening the shutter. The pulse motor 11 reverses the driving member 13 to the reference position specific seconds later to close the shutter in the beginning of the reversing and reset the lens in the latter half of the reversing, thereby finishing a series of operations. Consequently, one pulse motor drives the lens and also opens and closed the shutter, and the need for a magnet, etc., is eliminated. |
