Driving unit, optical unit, imaging apparatus, and endoscope
The drive unit includes a tubular fixed part, a tubular movable part, and a voice coil motor. The tubular fixed part is with a given axis as center, a tubular movable part 3 is located inside of the fixed part and having the axis as center, and a voice coil motor is capable of moving the movable part relatively with respect to the fixed part in the axial direction by a coil located in the fixed part and a magnet located in the movable part. In a state where the magnet is placed in the movable part, a first distance from the axis to the diametrically outer surface of the magnet is longer than a second distance from the axis to the inner circumference surface of the fixed part.
1. A drive unit comprising:
a tubular fixed part with a central axis as center,
a tubular movable part located inside of the fixed part and having the central axis as center, and
a voice coil motor capable of moving the movable part relatively with respect to the fixed part in an axial direction, the voice coil motor including a coil located on an outer circumferential surface of the fixed part and a magnet located in the movable part,
wherein:
the fixed part is provided with a hole in a position corresponding to a diametrically outer surface of the magnet,
a part of the magnet is located in the hole,
in a state where the magnet is placed in the movable part, a first distance from the central axis to the diametrically outer surface of the magnet is longer than a second distance from the central axis to an inner circumferential surface of the fixed part;
a step portion comprising a plane orthogonal to a diametrical direction is formed on an outer circumference surface of the movable part, and
the magnet is located on the step portion.
2. An optical unit comprising:
the drive unit according to claim 1 ; and
an optical member configured to be movable with the movable part.
3. An imaging apparatus, comprising:
the drive unit according to claim 1 ;
an optical member configured to be movable with the movable part; and
an imaging device on which light passing through the optical member is incident.
4. An endoscope comprising:
an insert part configured to be inserted through an interior of a body;
the drive unit according to claim 1 , the drive unit being disposed in the insert part;
an optical member configured to be movable with the movable part; and
an imaging device on which light passing through the optical member is incident.
5. A drive unit comprising:
a tubular fixed part with a central axis as center,
a tubular movable part located inside of the fixed part and having the central axis as center, and
a voice coil motor capable of moving the movable part relatively with respect to the fixed part in an axial direction, the voice coil motor including a coil located on an outer circumferential surface of the fixed part and a magnet located in the movable part,
wherein:
the fixed part is provided with a hole in a position corresponding to a diametrically outer surface of the magnet,
a part of the magnet is located in the hole,
in a state where the magnet is placed in the movable part, a first distance from the central axis to the diametrically outer surface of the magnet is longer than a second distance from the central axis to an inner circumferential surface of the fixed part; and
the diametrically outer surface of the magnet is a plane.
6. An optical unit comprising:
the drive unit according to claim 5 ; and
an optical member configured to be movable with the movable part.
7. An imaging apparatus, comprising:
the drive unit according to claim 5 ;
an optical member configured to be movable with the movable part; and
an imaging device on which light passing through the optical member is incident.
8. An endoscope comprising:
an insert part configured to be inserted through an interior of a body;
the drive unit according to claim 5 , the drive unit being disposed in the insert part;
an optical member configured to be movable with the movable part; and
an imaging device on which light passing through the optical member is incident.