Lens module, camera module, electronic device, and lens drive method

A camera module, comprising:

• a lens;
• a lens tube, wherein
• a central axis of the lens tube is parallel to an optical axis of the lens, and
• the lens tube is configured to hold the lens inside;
• a casing configured to house the lens tube inside;
• a first coil around an outer circumferential surface of the lens tube;
• a magnet on an inner circumferential surface of the casing, wherein
• the magnet is opposite to the first coil,
• the magnet is divided in plurality in a direction of the optical axis, and
• the lens tube is configured to move in a direction along the optical axis based on a magnetic interaction between the first coil and the magnet when a current is supplied to the first coil;
• a second coil around the inner circumferential surface of the casing, wherein
• the second coil is between the plurality of divided magnets, and
• the second coil is configured to detect a position of the lens along the optical axis based on an induced electromotive force generated on the second coil when the current is supplied to the first coil;
• and
• an imaging element on the optical axis, wherein the imaging element is configured to convert light transmitted through the lens into an electric signal.

An electronic device, comprising:

• a lens;
• a lens tube, wherein
• a central axis of the lens tube is parallel to an optical axis of the lens, and
• the lens tube is configured to hold the lens inside;
• a casing configured to house the lens tube inside;
• a first coil around an outer circumferential surface of the lens tube;
• a magnet on an inner circumferential surface of the casing, wherein
• the magnet is opposite to the first coil,
• the magnet is divided in plurality in a direction of the optical axis, and
• the lens tube is configured to move in a direction along the optical axis based on a magnetic interaction between the first coil and the magnet when a current is supplied to the first coil;
• a second coil around the inner circumferential surface of the casing, wherein
• the second coil is between the plurality of divided magnets, and
• the second coil is configured to detect a position of the lens based on an induced electromotive force generated on the second coil when the current is supplied to the first coil;
• an imaging element on the optical axis, wherein the imaging element is configured to convert light transmitted through the lens into an electric signal;
• and
• a control portion configured to:
• control supply of the current to the first coil;
• and
• control the position of the lens along the optical axis based on the induced electromotive force generated on the second coil.

A lens drive method, comprising:

• moving a lens tube along an optical axis of a lens based on a magnetic interaction between a first coil and a magnet opposite to the first coil when a current is supplied to the first coil, wherein
• the first coil is around an outer circumferential surface of the lens tube,
• the lens tube is configured to hold the lens inside,
• the magnet is on an inner circumferential surface of a casing configured to hold the lens tube inside, and
• the magnet is divided in plurality in a direction of the optical axis;
• detecting an induced electromotive force generated on a second coil around the inner circumferential surface of the casing;
• and
• controlling the current supplied to the first coil based on the detected induced electromotive force.