Camera module including an auto-focusing and shake-correcting lens driving device, camera mounting apparatus and calibration method for camera module
A camera module comprises: an AF driving part, a shake-correcting driving part, a first position detection part, a second position detection part, and a drive control part configured to perform driving control of the AF driving part based on detection results of the first position detection part and the second position detection part. The drive control part includes a correction part configured to correct the position of the AF movable part in the optical axis direction that is calculated based on the detection result of the first position detection part in accordance with preliminarily set correction data. The correction part corrects the detection result of the first position detection part in consideration of displacement of the AF movable part in the optical axis direction due to sway of the shake correction movable part.
1. A camera module, comprising:
an auto-focusing driving part including an auto focus movable part in which a lens part is disposed, and an auto focus fixing part disposed away from the auto focus movable part, the auto-focusing driving part being configured to move the auto focus movable part with respect to the auto focus fixing part in an optical axis direction;
a shake-correcting driving part including a shake correction movable part and a shake correction fixing part disposed away from the shake correction movable part, the shake correction movable part including the auto focus movable part and the auto focus fixing part, the shake-correcting driving part being configured to sway the shake correction movable part with respect to the shake correction fixing part in an optical axis orthogonal plane orthogonal to the optical axis direction;
a first position detection part including a first position detection magnet disposed in the auto focus movable part, and a first Hall device disposed opposite the first position detection magnet in the optical axis direction in the shake correction fixing part, the first position detection part being configured to detect a position of the auto focus movable part in the optical axis direction;
a second position detection part including a second position detection magnet disposed in the shake correction movable part, and a second Hall device disposed opposite the second position detection magnet in the optical axis direction in the shake correction fixing part, the second position detection part being configured to detect a position of the shake correction movable part in the optical axis orthogonal plane; and
a hardware processor configured to perform driving control of the auto-focusing driving part on a basis of a detection result of the first position detection part and a detection result of the second position detection part,
wherein the hardware processor configured to correct, in accordance with preliminarily set correction data, the position of the auto focus movable part in the optical axis direction that is calculated based on the detection result of the first position detection part, and
wherein the hardware processor corrects the detection result of the first position detection part in consideration of a displacement of the auto focus movable part in the optical axis direction due to sway of the shake correction movable part.
2. The camera module according to claim 1 , wherein the hardware processor corrects the detection result of the first position detection part such that an output characteristic of the first Hall device has a linearity.
3. The camera module according to claim 1 , wherein the hardware processor corrects the detection result of the first position detection part in consideration of a control accuracy error thereof.
4. The camera module according to claim 3 , wherein
a position AF TTL of the auto focus movable part in the optical axis direction after correction based on the preliminarily set correction data is expressed as
AF TTL =AF ( Z )+ AF ( X )+ AF ( Y ), where
AF ( Z )= aZ 3 +bZ 2 +cZ+d,
AF ( X )= fX 2 +gX+h,
AF ( Y )= iY 2 +kY+I,
where Z represents the detection result of the first position detection part, X and Y represent the detection result of the second position detection part, and a, b, c, d, f, g, h, i, k and l are all constants.
5. The camera module according to claim 1 , wherein the first position detection magnet is a unipolar magnet, and is disposed such that a magnetization direction is aligned with the optical axis direction.
6. The camera module according to claim 5 , wherein the first position detection magnet has a columnar shape.
7. The camera module according to claim 1 , further comprising a shake correction supporting part configured to couple the shake correction movable part and the shake correction fixing part, and support the shake correction movable part in a swayable manner,
wherein the shake correction supporting part includes a suspension wire.
8. A camera mounting apparatus that is an information apparatus or a transport apparatus, the camera mounting apparatus comprising:
the camera module according to claim 1 .
9. A calibration method for a camera module, the camera module including:
an auto-focusing driving part including an auto focus movable part in which a lens part is disposed, and an auto focus fixing part disposed away from the auto focus movable part, the auto-focusing driving part being configured to move the auto focus movable part with respect to the auto focus fixing part in an optical axis direction;
a shake-correcting driving part including a shake correction movable part and a shake correction fixing part disposed away from the shake correction movable part, the shake correction movable part including the auto focus movable part and the auto focus fixing part, the shake-correcting driving part being configured to sway the shake correction movable part with respect to the shake correction fixing part in an optical axis orthogonal plane orthogonal to the optical axis direction;
a first position detection part including a first position detection magnet disposed in the auto focus movable part, and a first Hall device disposed opposite the position detection magnet in the optical axis direction in the shake correction fixing part, the first position detection part being configured to detect a position of the auto focus movable part in the optical axis direction;
a second position detection part including a second position detection magnet disposed in the shake correction movable part, and a second Hall device disposed opposite the second position detection magnet in the optical axis direction in the shake correction fixing part, the second position detection part being configured to detect a position of the shake correction movable part in the optical axis orthogonal plane; and
a hardware processor configured to perform driving control of the auto-focusing driving part on a basis of a detection result of the first position detection part and a detection result of the second position detection part, the calibration method comprising:
measuring the position of the auto focus movable part in the optical axis direction when the shake correction movable part is swayed in the optical axis orthogonal plane and associating a result of the measuring with a detection result of the first position detection part, and
generating correction data for correcting the detection result of the first position detection part in consideration of a displacement of the auto focus movable part in the optical axis direction due to sway of the shake correction movable part on a basis of a relationship between a result of the measuring and the detection result of the first position detection part.