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US 4,390,262 AGranted
Electromagnetically operated diaphragm shutter
AssigneeCanon Kabushiki Kaisha
InventorsMichio Hirohata, Yukio Ogawa, Tetsuya Taguchi
Life of this patent
Estimating the term…
Abstract
An electromagnetic diaphragm shutter mechanism is provided with an electromagnet in the form of a coil or a printed circuit pattern arranged on a sector ring of the shutter mechanism. With a magnetic field applied to the electromagnet, when current is caused to flow therethrough in a prescribed direction, the sector ring is driven to rotate. A light measuring diaphragm mechanism related to the exposure diaphragm of the shutter blades serves to control the shutter and to improve the accuracy of program control of the shutter, the sector ring being always urged to move in a direction to close the shutter.
Claims56
An electromagnetically operated diaphragm shutter including:
- (a) a plurality of shutter blades;
- (b) a sector ring drivingly connected to said shutter blades and operative upon rotation thereof to actuate said shutter blades to block and unblock a photo-taking light path;
- (c) permanent magnet members oriented relative to said sector ring to form a magnetic field having a direction parallel to the optical axis of an objective lens;
- (d) electrically conductive members fixedly mounted on said sector ring and arranged upon supply of a current thereto to effect movement of said ring;
- (e) aperture means provided through the wall of said sector ring to form a light metering optical path, said aperture means being located out of axial alignment with said conductive members on said sector ring;
- and
- (f) diaphragm means positioned in the light metering optical path, with at least one of said shutter blades serving as said diaphragm means, and with the size of an opening defined by said diaphragm means being correlated to the size of an aperture opening defined at any time by said shutter blades.
4 more elements
An electromagnetically operated exposure control device comprising:
- (a) a plurality of blades;
- (b) a rotor drivingly connected to said blades and operative upon rotation thereof to actuate said blades to control the amount of light passing through a photo-taking light path;
- (c) electrically conductive members fixedly mounted on both sides of said rotor;
- (d) a magnetic member oriented relative to said rotor to form a magnetic field having a predetermined direction relative to said electrically conductive members;
- and
- (e) a plurality of holes provided through the wall of said rotor, said holes being located symmetrically at positions other than the positions of said conductive members on said rotor, said conductive members on both sides of said rotor being connected with each other at least at one of said holes.
3 more elements
An electromagnetically operated exposure control device comprising:
- (a) a plurality of blades;
- (b) a rotor drivingly connected to said blades and operative upon rotation thereof to actuate said blades to control the amount of light passing through a photo-taking light path;
- (c) electrically conductive members fixedly mounted on both sides of said rotor;
- (d) a magnetic member oriented relative to said rotor to form a magnetic field having a predetermined direction relative to said electrically conductive members;
- (e) a plurality of holes provided through the wall of said rotor, said holes being located symmetrically at positions other than the positions of said conductive members on said rotor, said conductive members on both sides of said rotor being connected with each other at least at one of said holes;
- and
- (f) a member which is provided with an aperture for an auxiliary stop, said member being secured to the exposure control device, said auxiliary stop aperture being arranged to overlap one of said plurality of holes.
4 more elements
An electromagnetically operated exposure control device comprising:
- (a) a plurality of blades;
- (b) a rotor drivingly connected to said blades and operative upon rotation thereof to actuate said blades to control the amount of light passing through a photo-taking light path;
- (c) electrically conductive members fixedly mounted on said rotor, said conductive members being arranged to encompass the center of rotation of said rotor in a wave-like fashion relative to the center of rotation, one being disposed closer thereto and another further away therefrom;
- (d) a magnetic member oriented relative to said rotor to form a magnetic field having a predetermined direction relative to said electrically conductive members;
- and
- (e) a plurality of cutouts provided in the wall of said rotor located along the pattern of said wave-like arrangement of said conductive members but without being in contact with said conductive members.
3 more elements
An electromagnetically operated diaphragm shutter including:
- (a) a plurality of shutter blades;
- (b) a rotor drivingly connected to said shutter blades and operative upon rotation thereof to actuate said shutter blades to block and unblock a photo-taking light path;
- (c) electrically conductive members fixedly mounted on said rotor;
- (d) a magnetic member oriented relative to said rotor to form a magnetic field having a predetermined direction relative to said electrically conductive members;
- (e) a cutout provided through the wall of said rotor to permit a light metering optical path to extend therethrough, said cutout being located at positions other than the position of said conductive members on said rotor;
- (f) a member provided with an aperture for an auxiliary stop, said member being fixedly attached to said shutter, and said aperture being arranged to overlap said cutout provided in said rotor;
- and
- (g) diaphragm means positioned in the light metering optical path, said diaphragm means being arranged to define an opening of a size correlated to the size of an opening defined by said shutter blades.
5 more elements
Dependencies are inferred from the claim text.