Position sensor, optical head device, head moving mechanism, information recording and reproduction device and position control system
AssigneePanasonic Corporation
InventorsOsamu Mizuno, Hiroshi Yamamoto, Takuya Wada, Hideki Aikoh, Kanji Wakabayashi, Takatoshi Yukimasa
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Abstract
As imaging devices are miniaturized, and optical devices are miniaturized, lens moving mechanisms are also miniaturized. Thus, position sensors for them are required to be miniaturized and have high accuracy at low cost. A magnet of a pillar shape and a yoke which move in the X axis direction with respect to a magnetic field detection element are provided, and a shape of a cross section of the yoke which is orthogonal to a longitudinal direction of the magnet changes along the longitudinal direction.
Claims16
A position sensor, comprising:
- a magnetic field generation portion having a pillar shape, and which generates a magnetic field, the magnetic field generation portion having a first side and a second side opposite the first side;
- a magnetic field detection portion for detecting a magnetic flux density of a magnetic field generated by the magnetic field generation portion, and facing the first side;
- and
- a yoke fixed to the magnetic field generation portion so as to cover at least a part of the second side along a longitudinal direction of the magnetic field generation portion, the yoke having a first end and a second end,
- wherein one of the magnetic field generation portion and the magnetic field detection portion is movable relative to the other in a predetermined moving direction, so as to define a range of relative movement,
- wherein the yoke has leg portions extending toward a plane parallel to and along the first side of the magnetic field generation portion,
- wherein within a part of the range of relative movement, the yoke is U-shaped in a plane that is normal to an axis parallel to and along the predetermined moving direction, and
- wherein a shape of the leg portions of the yoke adjacent the first end of the yoke is different from a shape of the leg portions of the yoke adjacent the second end of the yoke.
A position sensor, comprising:
- a magnetic field generation portion having a pillar shape, a first side, and a second side opposite the first side, and which generates a magnetic field;
- a magnetic field detection portion for detecting a magnetic flux density of a magnetic field generated by the magnetic field generation portion, the magnetic field detection portion facing the first side of the magnetic field generation portion;
- and
- a yoke fixed to the magnetic field generation portion so as to cover at least a part of the second side along a longitudinal direction of the magnetic field generation portion, wherein
- one of the magnetic field generation portion and the magnetic field detection portion is movable relative to the other in a predetermined moving direction, so as to define a range of relative movement, and
- wherein the yoke has leg portions extending toward a plane parallel to and along the first side of the magnetic field generation portion,
- wherein within a part of the range of relative movement, the yoke is U-shaped in a plane that is normal to an axis parallel to and along the predetermined moving direction,
- wherein the yoke has a shape such that a magnetic flux density detected by the magnetic field detection portion changes as the magnetic field generation portion moves relative to the magnetic field detection portion, and
- wherein a shape of the leg portions of the yoke adjacent a first end of the yoke is different from a shape of the leg portions of the yoke adjacent a second end of the yoke.
Dependencies are inferred from the claim text.