Position detector, camera-shake compensation mechanism, and image capture apparatus

• US 20050258822A1
• Filed: 11/15/2004
• Published: 11/24/2005
• Est. Priority Date: 05/20/2004
• Status: Active Grant

• Current Assignee: Konica Minolta Photo Imaging Incorporated (Konica Minolta Inc.)
• Original Assignee: Konica Minolta Photo Imaging Incorporated (Konica Minolta Inc.)
• Inventors: Masuda, Satoshi, Kosaka, Akira, Hara, Yoshihiro
• Granted Patent: US 7,248,037 B2
• Time in Patent Office: Days
• US Class Current: 324/207.200
• CPC Class Codes: G01D 5/145 influenced by the relative movement between the Hall device and magnetic fields see G01R33/06
• CPC Class Codes: G02B 27/646 compensating for small deviations, e.g. due to vibration or shake movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68
• CPC Class Codes: G03B 17/02 Bodies
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/687 by shifting the lens or sensor position

Abstract

A position detector includes a pair of magnetic sensors spaced from each other and a magnetic force generator movable relative to the pair of magnetic sensors. The length of the magnetic force generator along the space between the magnetic sensors is equal to or larger than a length of a space between the magnetic sensors. Preferably, the length of the magnetic force generator along the space between the magnetic sensors is equal to or larger than a sum of the length of the space between the magnetic sensors and an allowable moving distance of the magnetic force generator.

Claims

1. A position detector comprising:

a magnetic-sensor pair including magnetic sensors spaced from each other;

a magnetic force generator; and

a controller for detecting relative positions of said magnetic force generator and said magnetic-sensor pair based on respective output values of said magnetic sensors, wherein

a length of said magnetic force generator along a first axis along which a first space between said magnetic sensors extends is equal to or larger than a length of said first space along said first axis.

2. The position detector according to claim 1, wherein

said length of said magnetic force generator along said first axis is equal to or larger than a sum of said length of said first space along said first axis and an allowable moving distance of said magnetic force generator along said first axis.

3. The position detector according to claim 1, wherein

said length of said magnetic force generator along said first axis is equal to or larger than a sum of said length of said first space along said first axis and an allowable moving distance of said magnetic force generator along said first axis, said allowable moving distance being set to be equal to or larger than said length of said first space along said first axis.

4. The position detector according to claim 1, wherein

a permanent magnet serving as said magnetic force generator is attached to a moving part,

said magnetic-sensor pair is attached to a fixed part, and

said controller detects a position of said moving part relative to said fixed part.

5. The position detector according to claim 1, wherein

said controller detects a difference in magnitude between said output values of said magnetic sensors, as a position output, and

said length of said magnetic force generator along said first axis is determined so that an evaluation value for evaluating linearity of a curve representing change in said difference which is responsive to positional change of said magnetic force generator meets a predetermined standard.

6. The position detector according to claim 1, wherein

said controller controls each of input values applied to said magnetic sensors such that a sum of magnitudes of said output values of said magnetic sensors is constant, and then detects a difference in magnitude between said output values of said magnetic sensors, as a position output, and

said length of said magnetic force generator along said first axis is determined so that an evaluation value for evaluating linearity of a curve representing change in said difference which is responsive to positional change of said magnetic force generator meets a predetermined standard.

7. The position detector according to claim 1, further comprising:

another magnetic-sensor pair including magnetic sensors spaced from each other along a second axis different from said first axis, wherein

a length of said magnetic force generator along said second axis is equal to or larger than a length of a second space between said magnetic sensors included in said another magnetic-sensor pair along said second axis.

8. The position detector according to claim 7, wherein

said length of said magnetic force generator along said second axis is equal to or larger than a sum of said length of said second space along said second axis and an allowable moving distance of said magnetic force generator along said second axis.

9. The position detector according to claim 8, wherein

said length of said magnetic force generator along said second axis is equal to or larger than a sum of said length of said second space along said second axis and said allowable moving distance of said magnetic force generator along said second axis, said allowable moving distance being set to be equal to or larger than said length of said second space along said second axis.

10. The position detector according to claim 7, wherein

said first axis and said second axis are perpendicular to each other.

11. The position detector according to claim 10, wherein

said magnetic sensors included in said magnetic-sensor pair and said another magnetic-sensor pair are arranged symmetrically with respect to a given point.

12. The position detector according to claim 11, wherein

said magnetic force generator is cylindrical.

13. The position detector according to claim 1, wherein

said magnetic force generator is prismatic.

14. A camera-shake compensation mechanism comprising:

a position detector for detecting relative positions of two objects which move relative to each other for compensating for camera shake; and

an actuator for actuating said two objects relative to each other based on results of detection carried out by said position detector, to compensate for said camera shake, wherein,

said position detector includes;

a magnetic-sensor pair including magnetic sensors spaced from each other;

a magnetic force generator; and

a controller for detecting relative positions of said magnetic force generator and said magnetic-sensor pair based on respective output values of said magnetic sensors, wherein

a length of said magnetic force generator along an axis along which a space between said magnetic sensors included in said magnetic-sensor pair extends is equal to or larger than a length of said space along said axis.

15. An image capture apparatus comprising:

a position detector for detecting relative positions of two objects which move relative to each other for compensating for camera shake, and

an actuator for actuating said two objects relative to each other based on results of detection carried out by said position detector, to compensate for said camera shake, wherein,

said position detector includes;

a magnetic-sensor pair including magnetic sensors spaced from each other;

a magnetic force generator; and

a controller for detecting relative positions of said magnetic force generator and said magnetic-sensor pair based on respective output values of said magnetic sensors, wherein

a length of said magnetic force generator along an axis along which a space between said magnetic sensors extends is equal to or larger than a length of said space along said axis.

16. An image capture apparatus comprising:

an image-capture optical system including a focusing lens;

a position detector;

a lens-position controller for detecting a position of said focusing lens using said position detector, to control said position of said focusing lens, wherein

said position detector includes;

a magnetic-sensor pair including magnetic sensors spaced from each other;

a magnetic force generator; and

a controller for detecting relative positions of said magnetic force generator and said magnetic-sensor pair based on respective output values of said magnetic sensors, wherein

a length of said magnetic force generator along an axis along which a space between said magnetic sensors extends is equal to or larger than a length of said space along said axis.

17. An image capture apparatus comprising:

an image-capture optical system including a zoom lens;

a position detector;

a lens-position controller for detecting a position of said zoom lens using said position detector, to control said position of said zoom lens, wherein

said position detector includes;

a magnetic-sensor pair including magnetic sensors spaced from each other;

a magnetic force generator; and

a controller for detecting relative positions of said magnetic force generator and said magnetic-sensor pair based on respective output values of said magnetic sensors, wherein

a length of said magnetic force generator along an axis along which a space between said magnetic sensors extends is equal to or larger than a length of said space along said axis.