Anti-shake apparatus having magnetic position detectors positioned on one axis with common input circuitry

• US 7,453,494 B2
• Filed: 03/08/2005
• Issued: 11/18/2008
• Est. Priority Date: 03/09/2004
• Status: Expired due to Fees

• Current Assignee: PENTAX RICOH IMAGING COMPANY, LTD.
• Original Assignee: Hoya Corporation
• Inventors: Uenaka, Yukio
• Primary Examiner(s): Vu, Ngoc-Yen
• Assistant Examiner(s): Saunders, Paul
• Application Number:
  US11/073,604
• Publication Number:
  US 20050200712A1
• Time in Patent Office: 1,351 Days
• Field of Search: 348/208.1, 348/208.2, 348/208.4, 348/208.5, 348/208.7, 348/208.11
• US Class Current: 348/208.7
• CPC Class Codes: G03B 2217/005 Blur detection
• CPC Class Codes: G03B 5/00 Adjustment of optical system relative to image or object surface other than for focusing
• CPC Class Codes: H04N 23/40 Circuit details for pick-up tubes

Abstract

An anti-shake apparatus of a photographing apparatus comprises a movable unit, a fixed unit, and a signal-processing unit. The movable unit has an imaging device and is movable in first and second directions. The fixed unit slidably supports the movable unit in both the first and second directions. The movable unit has a horizontal magnetic-field change-detecting element for detecting a first location, and a vertical magnetic-field change-detecting element for detecting a second location. The signal-processing unit outputs a first detected-position signal, which specifies the first location on the basis of output signals of the horizontal magnetic-field change-detecting element, and outputs a second detected-position signal, which specifies the second location on the basis of output signals of the vertical magnetic-field change-detecting element. Further, the signal-processing unit has a common input circuit which supplies electrical power to the input terminals of the horizontal and vertical magnetic-field change-detecting elements.

Claims

1. An anti-shake apparatus of a photographing apparatus, comprising:

a movable unit that has one of an imaging device and a hand-shake correcting lens, and that can be moved in first and second directions, said first direction being perpendicular to an optical axis of a camera lens of said photographing apparatus, and said second direction being perpendicular to said optical axis and said first direction;

a fixed unit that slidably supports said movable unit in both said first and second directions;

a signal-processing unit; and

a control unit that controls said movable unit, said fixed unit, and said signal-processing unit, and that has an A/D converter;

wherein

one of said movable unit and said fixed unit has a magnetic-field change-detecting unit which has a horizontal magnetic-field change-detecting element for detecting a position of said movable unit in said first direction as a first location, and a vertical magnetic-field change-detecting element for detecting a position of said movable unit in said second direction as a second location;

said signal-processing unit outputs a first detected-position signal, which specifies said first location on the basis of output signals of said horizontal magnetic-field change-detecting element, and outputs a second detected-position signal, which specifies said second location on the basis of output signals of said vertical magnetic-field change-detecting element, and has a common input circuit which supplies electrical power to input terminals of said horizontal and vertical magnetic-field change-detecting elements;

said control unit calculates said first location on the basis of an A/D converting operation by said A/D converter, for said first detected-position signal, and calculates said second location on the basis of an A/D converting operation by said A/D converter, for said second detected-position signal, and performs first and second initial-adjustment operations;

in said first initial-adjustment operation, the width between the minimum and maximum values of said first detected-position signal is maximized, in the movement range of said movable unit, and in the A/D converting range of said A/D converter;

in said second initial-adjustment operation, the width between the minimum and maximum values of said second detected-position signal is maximized, in the movement range of said movable unit, and in the A/D converting range of said A/D converter;

an optimized horizontal current-value for the current, which flows through said input terminals of said horizontal magnetic-field change-detecting element when detecting said first location, is calculated in said first initial-adjustment operation, which adjusts a first detecting-resolution when said first detected-position signal is A/D converted by said A/D converter, by changing the value of the current which flows through the input terminals of said horizontal magnetic-field change-detecting element; and

an optimized vertical current-value for the current, which flows through said input terminals of said vertical magnetic-field change-detecting element when detecting said second location, is calculated in said second initial-adjustment operation, which adjusts a second detecting-resolution when said second detected-position signal is A/D converted by said A/D converter, by changing the value of the current which flows through the input terminals of said vertical magnetic-field change-detecting element.

2. The anti-shake apparatus according to claim 1, wherein the input terminal of said horizontal magnetic-field change-detecting element is connected with the input terminal of said vertical magnetic-field change-detecting element in series.

3. The anti-shake apparatus according to claim 1, wherein the input terminal of said horizontal magnetic-field change-detecting element is connected in parallel with the input terminal of said vertical magnetic-field change-detecting element.

4. The anti-shake apparatus according to claim 1, wherein said movable unit has said magnetic-field change-detecting unit;

said magnetic-field change-detecting unit has one said horizontal magnetic-field change-detecting element and one said vertical magnetic-field change-detecting element; and

said fixed unit has a position-detecting magnet unit which has a first position-detecting magnet which is used for detecting said first location and faces said horizontal magnetic-field change-detecting element, and a second position-detecting magnet which is used for detecting said second location and faces said vertical magnetic-field change-detecting element.

5. The anti-shake apparatus according to claim 4, wherein said movable unit has a first driving coil which is used for moving said movable unit in said first direction, and a second driving coil which is used for moving said movable unit in said second direction;

said first position-detecting magnet is used for moving said movable unit in said first direction; and

said second position-detecting magnet is used for moving said movable unit in said second direction.

6. The anti-shake apparatus according to claim 1, wherein said optimized horizontal current-value is the smaller value of first and second horizontal current-values;

said optimized vertical current-value is the smaller value of first and second vertical current-values;

said first horizontal current-value is the value of the current which flows through said input terminals of said horizontal magnetic-field change-detecting element, when the output value of said first detected-position signal is the same as the maximum value in the A/D converting range of said A/D converter, when said movable unit contacts a first horizontal edge-point which is one of the edge-points in a movement range of said movable unit in said first direction;

said second horizontal current-value is the value of the current which flows through said input terminals of said horizontal magnetic-field change-detecting element, when the output value of said first detected-position signal is the same as the minimum value in the A/D converting range of said A/D converter, when said movable unit contacts a second horizontal edge-point which is another of the edge-points in said movement range of said movable unit, in said first direction;

said first vertical current-value is the value of the current which flows through said input terminals of said vertical magnetic-field change-detecting element, when the output value of said second detected-position signal is the same as the maximum value in the A/D converting range of said A/D converter, when said movable unit contacts a first vertical edge-point which is one of the edge-points in a movement range of said movable unit, in said second direction; and

said second vertical current-value is the value of the current which flows said input terminals of said vertical magnetic-field change-detecting element, when the output value of said second detected-position signal is the same as the minimum value in the A/D converting range of said A/D converter when said movable unit contacts a second vertical edge-point which is another of the edge-points in said movement range of said movable unit in said second direction.

7. The anti-shake apparatus according to claim 1, further comprising a memory unit that is connected with said control unit, and stores said optimized horizontal current-value and said optimized vertical current-value;

a content which is stored in said memory unit is not deleted even if said memory unit is set to the off state.

8. The anti-shake apparatus according to claim 1, wherein current having said optimized horizontal current-value, flows through said input terminals of said horizontal and vertical magnetic-field change-detecting elements, from said control unit, through said common input circuit, when detecting said first location;

and

current having said optimized vertical current-value, flows through said input terminals of said horizontal and vertical magnetic-field change-detecting elements, from said control unit, through said common input circuit, when detecting said second location.

9. The anti-shake apparatus according to claim 1, wherein said control unit has first and second A/D converters;

said A/D converting operation for said first detected-position signal is performed by said first A/D converter; and

said A/D converting operation for said second detected-position signal is performed by said second A/D converter.

10. The anti-shake apparatus according to claim 1, wherein said magnetic-field change-detecting unit is a one-axis hall element;

and

said horizontal magnetic-field change-detecting element and said vertical magnetic-field change-detecting element are hall elements.