Patent ID: 6924946
Filing Date: 2005-08-02
Classification: G02B,G03B

Abstract:
1. A diaphragm device comprising two diaphragm vanes that respectively have notches opposed to each other in a single plane perpendicular to an optical axis, two of the vanes being moved close to and apart from each other in the single plane so as to vary an aperture of the diaphragm, and two optical filters having regular transmissivity attached to the diaphragm vanes to shield deeper recesses of the notches, the two optical filters being movable with the vanes to create a region of overlap of the two optical filters for reducing a quantity of a beam of light passing through the diaphragm, wherein an aperture of the diaphragm defined by edges of the optical filters is shaped to be asymmetrical about a straight line which crosses the optical axis and is perpendicular to directions of the motion of the vanes.