Electromagnetic actuator and lens drive mechanism using the same
First Claim
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1. An electromagnetic actuator comprising:
- a cylindrical casing having a first supporting rail extending in parallel to the central axis of said casing;
a yoke member which is disposed in said casing and made up of a cylindrical inner yoke having a first cut portion opening in the direction parallel to the central axis and a cylindrical outer yoke covering said inner yoke;
a magnet fixed on said yoke member;
a holding member which holds a driven body having a generally circular radial cross section;
a cylindrical coil bobbin which is greater in diameter than said driven body holding member, with a coil being wound thereon coaxially;
a first connecting arm which connects said coil bobbin to said driven body holding member in a generally concentric relation and is located in the first cut portion of said inner yoke; and
a bearing device which is provided on said first connecting arm or said driven body holding member and supported slidably on said first supporting rail.
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Abstract
An electromagnetic actuator for moving a focusing lens along an optical axis includes a lens barrel having two supporting rails, a set of cylindrical inner and outer yokes incorporating a pair of magnets, a lens holder which holds the lens and is supported slidably on the supporting rails by means of a bearing device and rail guide provided on two arms of the lens holder, a coil wound on a bobbin which is fixed on the lens holder and located so that the coil is exposed to the magnetic field of the magnets inside the yokes. The yokes have cut portions, allowing the arms of lens holder to cut into the yokes when the lens is moved.
117 Citations
8 Claims
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1. An electromagnetic actuator comprising:
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a cylindrical casing having a first supporting rail extending in parallel to the central axis of said casing; a yoke member which is disposed in said casing and made up of a cylindrical inner yoke having a first cut portion opening in the direction parallel to the central axis and a cylindrical outer yoke covering said inner yoke; a magnet fixed on said yoke member; a holding member which holds a driven body having a generally circular radial cross section; a cylindrical coil bobbin which is greater in diameter than said driven body holding member, with a coil being wound thereon coaxially; a first connecting arm which connects said coil bobbin to said driven body holding member in a generally concentric relation and is located in the first cut portion of said inner yoke; and a bearing device which is provided on said first connecting arm or said driven body holding member and supported slidably on said first supporting rail. - View Dependent Claims (2, 3, 4)
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5. A lens drive mechanism for moving a lens electromagnetically comprising:
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a lens barrel having a first supporting rail extending in parallel to the optical axis of said lens; a yoke member which is disposed inside said lens barrel and made up of a cylindrical inner yoke having a first cut portion extending in the direction parallel to the optical axis and a cylindrical outer yoke covering said inner yoke; a magnet fixed on said yoke member; a lens holder which holds said lens; a cylindrical coil bobbin which is greater in diameter than said lens holder, with a coil being wound thereon coaxially; a first connecting arm which connects said coil bobbin to said lens holder in a generally concentric relation and is located in the first cut portion of said inner yoke; and a bearing device which is provided on said first connecting arm or said lens holder and supported slidably on said first supporting rail. - View Dependent Claims (6, 7, 8)
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Specification