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US 6,719,463 B2Granted
Drive apparatus, light quantity adjusting apparatus, and lens drive apparatus
AssigneeCanon Kabushiki Kaisha
InventorChikara Aoshima
Life of this patent
Estimating the term…
Abstract
A feature of the present invention resides in that when a value of a ratio of a central angle of an outer magnetic pole portion to a central angle of each magnetized pole of a magnet portion is referred to as Y, and a value of a ratio of a thickness of the magnet portion in a diameter direction to a circumferential length of each magnetized pole of the magnet portion is referred to as X, the following condition is satisfied: −0.3X+0.63>Y.
Claims11
A drive apparatus comprising:
- a rotor that has a magnet portion having a cylindrical shape whose outer peripheral surface is circumferentially divided into sections that are magnetized to have different poles, and is capable of rotating about an axis;
- at least one outer magnetic pole portion that is formed so as to protrude and extend parallel to the axis and opposes the outer peripheral surface of the magnet portion;
- an inner magnetic pole portion disposed at a position opposing the outer magnetic pole portion so as to oppose an inner peripheral surface of the magnet portion;
- and
- a coil that is disposed in an axis direction of the rotor and excites the outer magnetic pole portion and the inner magnetic pole portion,
- wherein the rotor is maintained at two stoppage positions, and when a value of a ratio of a central angle of the outer magnetic pole portion to a central angle of each magnetized pole of the magnet portion is referred to as Y, and a value of a ratio of a thickness of the magnet portion in a diameter direction to a circumferential length of each magnetized pole of the magnet portion is referred to as X, the following condition is satisfied:
- −0.3X+0.63>Y.
4 more elements
A light quantity adjusting comprising:
- a rotor that has a magnet portion having a cylindrical shape whose outer peripheral surface is circumferentially divided into sections that are magnetized to have different poles, and is capable of rotating about an axis;
- an output member that operates in accordance with rotation of the rotor;
- at least one outer magnetic pole portion that is formed so as to protrude and extend parallel to the axis and opposes the outer peripheral surface of the magnet portion;
- an inner magnetic pole portion disposed at a position opposing the outer magnetic pole portion so as to oppose an inner peripheral surface of the magnet portion;
- a coil that is disposed in an axis direction of the rotor and excites the outer magnetic pole portion and the inner magnetic pole portion;
- a ground board provided with an opening portion;
- and
- a light quantity adjusting member that is driven by the output member so as to move between a position closing the opening portion of the ground board and a position away from the opening portion, and changes a light quantity passing through the opening portion,
- wherein the light quantity adjusting member is maintained at two stoppage positions, and when a value of a ratio of a central angle of the outer magnetic pole portion to a central angle of each magnetized pole of the magnet portion is referred to as Y, and a value of a ratio of a thickness of the magnet portion in a diameter direction to a circumferential length of each magnetized pole of the magnet portion is referred to as X, the following condition is satisfied:
- −0.3X+0.63>Y.
7 more elements
A lens drive apparatus comprising:
- a rotor that has a magnet portion having a cylindrical shape whose outer peripheral surface is circumferentially divided into sections that are magnetized to have different poles, and is capable of rotating about an axis;
- an output member that operates in accordance with rotation of the rotor;
- at least one outer magnetic pole portion that is formed so as to protrude and extend parallel to the axis and opposes the outer peripheral surface of the magnet portion;
- an inner magnetic pole portion disposed at a position opposing the outer magnetic pole portion so as to oppose an inner peripheral surface of the magnet portion;
- a coil that is disposed in an axis direction of the rotor and excites the outer magnetic pole portion and the inner magnetic pole portion;
- a ground board provided with an opening portion;
- and
- a lens that is driven by the output member so as to move between a position closing the opening portion of the ground board and a position away from the opening portion, and changes a focal length of a luminous flux passing through the opening portion,
- wherein the lens is maintained at two stoppage positions, and when a value of a ratio of a central angle of the outer magnetic pole portion to a central angle of each magnetized pole of the magnet portion is referred to as Y, and a value of a ratio of a thickness of the magnet portion in a diameter direction to a circumferential length of each magnetized pole of the magnet portion is referred to as X, the following condition is satisfied:
- −0.3X+0.63>Y.
7 more elements
Dependencies are inferred from the claim text.