Position detection device, lens module, imaging apparatus, and distance measurement apparatus
A position detection device includes a magnetic sensor and a first magnetic field generator. The first magnetic field generator is disposed to be spaced from and face the magnetic sensor in a first-axis direction, includes a first multipolar magnet, and generates a first magnetic field to be exerted on the magnetic sensor, the first multipolar magnet including N poles and S poles, the N and S poles being adjacent in the first-axis direction. The magnetic sensor and the first magnetic field generator are provided to be relatively movable with respect to each other in a second-axis direction orthogonal to the first-axis direction. A center position of the magnetic sensor in a third-axis direction orthogonal to both the first-axis direction and the second-axis direction is different from a center position of the first multipolar magnet in the third-axis direction.
1 . A position detection device comprising:
a magnetic sensor; and
a first magnetic field generator disposed to be spaced from and face the magnetic sensor in a first-axis direction, including a first multipolar magnet, and generating a first magnetic field to be exerted on the magnetic sensor, the first multipolar magnet including a plurality of N poles and a plurality of S poles, the N and S poles being adjacent to each other in the first-axis direction, wherein
the magnetic sensor and the first magnetic field generator are provided to be relatively movable with respect to each other in a second-axis direction orthogonal to the first-axis direction, and
a center position of the magnetic sensor in a third-axis direction orthogonal to both the first-axis direction and the second-axis direction is different from a center position of the first multipolar magnet in the third-axis direction.
2 . The position detection device according to claim 1 , wherein a dimension of the first multipolar magnet in the first-axis direction is smaller than a dimension of the first multipolar magnet in the third-axis direction.
3 . The position detection device according to claim 1 , wherein at least a portion of the magnetic sensor and at least a portion of the first multipolar magnet overlap each other in the first-axis direction.
4 . The position detection device according to claim 1 , wherein the second-axis direction comprises a direction of rotation around a rotation center axis along the third-axis direction.
5 . The position detection device according to claim 1 , wherein the second-axis direction comprises a direction of rotation around a rotation center axis along the first-axis direction.
6 . The position detection device according to claim 1 , wherein the first multipolar magnet has a curved shape in a first plane orthogonal to the third-axis direction.
7 . The position detection device according to claim 1 , wherein the first multipolar magnet has a substantially rectangular parallelepiped outer shape as a whole.
8 . The position detection device according to claim 1 , wherein the first multipolar magnet has a curved shape in a second plane orthogonal to the first-axis direction.
9 . The position detection device according to claim 1 , wherein
the first magnetic field includes a first magnetic field component, and a second magnetic field component having a phase difference with respect to the first magnetic field component, and
the magnetic sensor generates a detection signal corresponding to a direction of a magnetic field to be detected in which the first magnetic field component and the second magnetic field component are composited in a plane orthogonal to the first-axis direction, and is able to detect a change in position of the first magnetic field generator.
10 . The position detection device according to claim 1 , wherein
the first multipolar magnet includes a first N pole and a second N pole as the plurality of N poles, and includes a first S pole and a second S pole as the plurality of S poles,
the first N pole and the first S pole are disposed adjacent to each other in the first-axis direction,
the second N pole and the second S pole are disposed adjacent to each other in the first-axis direction,
the first N pole and the second S pole are disposed adjacent to each other in the second-axis direction, and
the second N pole and the first S pole are disposed adjacent to each other in the second-axis direction.
11 . The position detection device according to claim 1 , wherein the first multipolar magnet includes
a first region portion magnetized in a first direction along the first-axis direction, and
a second region portion magnetized in a second direction that is along the first-axis direction and opposite to the first direction.
12 . The position detection device according to claim 11 , wherein the first multipolar magnet further includes a neutral zone between the first region portion and the second region portion.
13 . The position detection device according to claim 12 , wherein the neutral zone extends along a third plane orthogonal to the second-axis direction.
14 . The position detection device according to claim 1 , wherein the first multipolar magnet has a longitudinal direction along the second-axis direction.
15 . The position detection device according to claim 1 , wherein an interface between the N and S poles adjacent to each other in the first-axis direction extends along a first plane orthogonal to the first-axis direction.
16 . The position detection device according to claim 1 , wherein the magnetic sensor and the first multipolar magnet are provided to be relatively movable with respect to each other along the second-axis direction while keeping a state of overlapping each other in the first-axis direction.
17 . The position detection device according to claim 1 , further comprising a second magnetic field generator generating a second magnetic field, wherein
the first magnetic field generator is provided to be movable along the second-axis direction with respect to the magnetic sensor and the second magnetic field generator owing to the second magnetic field.
18 . A lens module comprising:
a magnetic sensor;
a first magnetic field generator disposed to be spaced from and face the magnetic sensor in a first-axis direction, including a first multipolar magnet, and generating a first magnetic field to be exerted on the magnetic sensor, the first multipolar magnet including a plurality of N poles and a plurality of S poles, the N and S poles being adjacent to each other in the first-axis direction;
a second magnetic field generator generating a second magnetic field; and
a lens, wherein
the magnetic sensor and the second magnetic field generator are provided to be relatively movable with respect to the first magnetic field generator and the lens in a second-axis direction orthogonal to the first-axis direction, and
a center position of the magnetic sensor in a third-axis direction orthogonal to both the first-axis direction and the second-axis direction is different from a center position of the first multipolar magnet in the third-axis direction.
19 . An imaging apparatus comprising
an imaging element, and
a lens module, wherein
the lens module includes:
a magnetic sensor;
a first magnetic field generator disposed to be spaced from and face the magnetic sensor in a first-axis direction, including a first multipolar magnet, and generating a first magnetic field to be exerted on the magnetic sensor, the first multipolar magnet including a plurality of N poles and a plurality of S poles, the N and S poles being adjacent to each other in the first-axis direction;
a second magnetic field generator generating a second magnetic field; and
a lens,
the magnetic sensor and the second magnetic field generator are provided to be relatively movable with respect to the first magnetic field generator and the lens in a second-axis direction orthogonal to the first-axis direction, and
a center position of the magnetic sensor in a third-axis direction orthogonal to both the first-axis direction and the second-axis direction is different from a center position of the first multipolar magnet in the third-axis direction.
20 . A distance measurement apparatus that measures a distance to a target object by detecting emitted light, the distance measurement apparatus comprising:
an optical element configured to change a direction of travel of the light and to rotate;
a magnetic sensor; and
a magnetic field generator disposed to be spaced from and face the magnetic sensor in a first-axis direction, including a multipolar magnet, and generating a magnetic field to be exerted on the magnetic sensor, the multipolar magnet including a plurality of N poles and a plurality of S poles, the N and S poles being adjacent to each other in the first-axis direction, wherein
the magnetic sensor and the magnetic field generator are provided to be relatively movable with respect to each other in a second-axis direction orthogonal to the first-axis direction,
the magnetic field generator is configured to rotate in the second-axis direction around a rotation axis in conjunction with the optical element, and
a center position of the magnetic sensor in a third-axis direction orthogonal to both the first-axis direction and the second-axis direction is different from a center position of the first multipolar magnet in the third-axis direction.
21 . The position detection device according to claim 2 , wherein at least a portion of the magnetic sensor and at least a portion of the first multipolar magnet overlap each other in the first-axis direction.
22 . The position detection device according to claim 1 , wherein
the plurality of N poles includes a first N pole and a second N pole,
the plurality of S poles includes a first S pole and a second S pole,
the first N pole and the first S pole are adjacent to each other in the first-axis direction, and
the second N pole and the second S pole are adjacent to each other in the first-axis direction.