| 摘要 |
A diaphragm device for a digital camera having an optical image input system including a photographing element for converting an optical image input by an optical system to electric signals and a signal processor for applying predetermined signal processing to the electric signals obtained by the photographing element. The diaphragm device adjusts an exposure time by controlling incident luminous flux to the photographing element and an electric charge storage time of the photographing element. The diaphragm device includes a diaphragm sheet rotatably arranged around a rotation central shaft which is set in parallel with a photographing optical axis of the optical system. The diaphragm sheet has a plurality of diaphragm apertures having different diameters arranged in a turret shape on a reference circle around the rotation central shaft. The diaphragm device includes a rotary ring arranged rotatably in forward and reverse directions around the photographing optical axis and a click member is retained by the rotary ring rotatably only in one direction so as to rotate the diaphragm sheet in one direction. A rotation driving device drives the rotary ring to rotate, and a positioning mechanism fastens the diaphragm sheet in a position setting a selected diaphragm aperture.
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