IP Library › Granted Patent US 7,777,978
Granted Patent B2
US 7,777,978 · App. 11/947,354 · Granted Aug 17, 2010

Lens barrel

Assignee: Canon Kabushiki Kaisha
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Quick Facts
Patent No.
US 7,777,978
App. No.
11/947,354
Granted
Aug 17, 2010
Kind
B2
Abstract

A lens barrel with improved precision is obtained by reducing fitting play of a lens barrel. A coil and a magnetic member are fixed on a lens holding member, and a magnet and a yoke are fixed on an outer barrel. When energizing the coil, the lens holding member moves in the optical axis direction along guide bars by magnetic fluxes from the magnet. The magnetic member receives a magnetic attraction force toward the magnet by leakage fluxes. In the lens holding member, a bearing sleeve is biased by the attraction force perpendicularly to the axis of the guide bar, and the resultant force of the attraction force and a gravitational force exerted on the lens holding member removes play. A resultant force of a force toward the guide bar exerted on the bearing and the gravitational force thereon removes fitting play between the bearing and the guide bar.

Claims (6)

1. A lens barrel comprising:

a lens holding member that holds a lens; and

a voice coil motor that drives the lens holding member along a guide member,

wherein: a coil of the voice coil motor is fixedly attached on the lens holding member; a magnetic circuit element is formed by a yoke of the voice coil motor and by a board-shaped magnet attached to the yoke; and the magnetic circuit element is fixedly attached on a fixed portion that holds the lens holding member,

wherein a stick of magnetic member is fixedly attached on the lens holding member, and the lens holding member is shifted in one direction relative to the guide member by means of a magnetic attraction force acting between the stick of magnetic member and the board-shaped magnet of the voice coil motor, and

wherein a movable range of the stick of magnetic member in the optical axis direction is within a range of an entire length of the board-shaped magnet along the optical axis direction.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Dec 19, 2007
From: SATO, TAKEHIKO
To: CANON KABUSHIKI KAISHA
Reel/Frame 020265/0884 →
Priority Claims (1)
JP 2006-339482 · Dec 18, 2006 · national
Continuity (1)
Related Publication 20080144198A1 · Jun 19, 2008