Anti-shake apparatus

• US 20050195287A1
• Filed: 03/04/2005
• Published: 09/08/2005
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: PENTAX RICOH IMAGING COMPANY, LTD.
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Uenaka, Yukio
• Granted Patent: US 7,495,693 B2
• Time in Patent Office: Days
• US Class Current: 348/208.99
• CPC Class Codes: G03B 2205/0015 by displacing one or more optical elements normal to the optical axis
• CPC Class Codes: G03B 2205/0069 using electromagnetic actuators, e.g. voice coils
• CPC Class Codes: G03B 5/02 Lateral adjustment of lens
• CPC Class Codes: H04N 23/40 Circuit details for pick-up tubes
• CPC Class Codes: H04N 23/60 Control of cameras or camera modules
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6812 based on additional sensors, e.g. acceleration sensors
• CPC Class Codes: H04N 23/687 by shifting the lens or sensor position

Abstract

An anti-shake-apparatus comprises a movable-unit, a fixed-unit, a signal-processor, and a controller. The movable-unit has an imaging-device and is movable in first- and second-directions. The fixed-unit has a hall-element-unit. The controller controls the movable-unit, the fixed-unit, and the signal-processor, and has first- and second-A/D-converters. The hall-element-unit has first and second horizontal-hall-elements for detecting a first-location, and first and second vertical-hall-elements for detecting a second-location. The movable-unit has a magnetic-field-generating unit having a coil for detecting the first- and second-locations. The signal-processor outputs a first-signal, specifying the first-location from the horizontal-hall-elements, to the first-A/D-converter, and a second-signal, specifying the second-location from the vertical-hall-elements, to the second-A/D-converter. The controller calculates the first-location from an A/D-converting operation of the first-signal, and the second-location from an A/D-converting operation of the second-signal. An current-value is calculated in an initial-adjustment-operation adjusting a detecting-resolution in A/D-converting the first- and second-signals, and flows through the coil.

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, and that has a magnetic-field change-detecting unit;

a signal-processing unit; and

a control unit that controls said movable unit, said fixed unit, and said signal-processing unit, and that has first and second A/D converters;

said magnetic-field change-detecting unit having first and second horizontal magnetic-field change-detecting elements for detecting a position of said movable unit in said first direction as a first location, and first and second vertical magnetic-field change-detecting elements for detecting a position of said movable unit in said second direction as a second location;

said movable unit having a position-detecting magnetic-field generating unit which is used for detecting said first and second locations, and which faces said magnetic-field change-detecting unit, and which has a position-detecting coil;

said position-detecting coil being magnetized by being electrified where an N pole and an S pole are arranged in a third direction which is parallel to said optical axis, and said position-detecting coil being wound, such that its outer circumference shape, viewed from said third direction, is a rectangular shape and faces said magnetic-field change-detecting unit, an external structure of said rectangular shape forming lines which are parallel to one of said first direction and said second direction;

said signal-processing unit outputting a first detected-position signal, which specifies said first location on the basis of output signals of said first and second horizontal magnetic-field change-detecting elements, to said first A/D converter, and outputting a second detected-position signal, which specifies said second location on the basis of output signals of said first and second vertical magnetic-field change-detecting elements, to said second A/D converter;

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

an optimized coil current-value being calculated in an initial-adjustment operation which adjusts a detecting-resolution when said first and second detected-position signals are A/D converted by said first and second A/D converters, by changing the value of the current which flows through said position-detecting coil; and

current having said optimized coil current-value, flowing through said position-detecting coil when detecting the position of said movable unit.

2. The anti-shake apparatus according to claim 1, wherein said optimized coil current-value is the smallest value of first, second, third, and fourth coil current-values;

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

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

said third coil current-value is the value of the current which flows through said position-detecting coil, under the condition where the output value of said second detected-position signal is the same as the maximum value in the A/D converting range of said second A/D converter, when said movable unit contacts a first vertical edge-point which is one of the edge-points of a movement range of said movable unit in said second direction; and

said fourth coil current-value is the value of the current which flows through said position-detecting coil, under the condition where the output value of said second detected-position signal is the same as the minimum value in the A/D converting range of said second A/D converter, when said movable unit contacts a second vertical edge-point which is another of the edge-points of said movement range of said movable unit in said second direction.

3. The anti-shake apparatus according to claim 1, further comprising a memory unit that is connected with said control unit, and stores said optimized coil 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.

4. The anti-shake apparatus according to claim 1, wherein said movable unit is located at the center of its movement range, in both said first and second directions, when the center area of one of said imaging device and said hand-shake correcting lens which is included in said movable unit, is located on said optical axis.

5. The anti-shake apparatus according to claim 4, wherein when the center of one of said imaging device and said hand-shake correcting lens which is included in said movable unit passes through said optical axis, said first horizontal magnetic-field change-detecting element is located at a place which faces midway along a side of said rectangular outer circumference, in said second direction, of said position-detecting coil;

said second horizontal magnetic-field change-detecting element is located at a place which faces midway along another side of said rectangular outer circumference, in said second direction, of said position-detecting coil;

said first vertical magnetic-field change-detecting element is located at a place which faces midway along a side of said rectangular outer circumference, in said first direction, of said position-detecting coil; and

said second vertical magnetic-field change-detecting element is located at a place which faces midway along another side of said rectangular outer circumference, in said first direction, of said position-detecting coil.

6. The anti-shake apparatus according to claim 1, wherein said position-detecting magnetic-field generating unit has a magnetic core;

said position-detecting coil is wound around said magnetic core;

said magnetic core is made of a magnetic material, and has a rectangular prism form; and

said rectangular prism form has a front-surface which faces said magnetic-field change-detecting unit and is a rectangular shape that is the same as said outer circumference of said position-detecting coil.

7. The anti-shake apparatus according to claim 1, wherein said position-detecting coil forms a seat and a spiral shape coil pattern.

8. The anti-shake apparatus according to claim 1, wherein said magnetic-field change-detecting unit is a two-axes hall element;

said first and second horizontal magnetic-field change-detecting elements are hall elements; and

said first and second vertical magnetic-field change-detecting elements are hall elements.

9. The anti-shake apparatus according to claim 1, wherein said outer circumference shape of said position-detecting coil is a square.

10. A method for adjusting a detecting-resolution when AND converting in an anti-shake apparatus of a photographing apparatus according to claim 1, comprising:

calculating a first coil current-value;

calculating a second coil current-value;

calculating a third coil current-value;

calculating a fourth coil current-value; and

calculating said optimized coil current-value on the basis of said first, second, third, and fourth coil current-values;

said optimized coil current-value being the smallest value of said first, second, third, and fourth coil current-values;

said first coil current-value being the value of the current which flows through said position-detecting coil, under the condition where the output value of said first detected-position signal is the same as the maximum value in the A/D converting range of said first A/D converter, when said movable unit contacts a first horizontal edge-point which is one of the edge-points of a movement range of said movable unit in said first direction;

said second coil current-value being the value of the current which flows through said position-detecting coil, under the condition where the output value of said first detected-position signal is the same as the minimum value in the A/D converting range of said first A/D converter, when said movable unit contacts a second horizontal edge-point which is another of the edge-points of said movement range of said movable unit in said first direction;

said third coil current-value being the value of the current which flows through said position-detecting coil, under the condition where the output value of said second detected-position signal is the same as the maximum value in the A/D converting range of said second A/D converter, when said movable unit contacts a first vertical edge-point which is one of the edge-points of a movement range of said movable unit in said second direction; and

said fourth coil current-value being the value of the current which flows through said position-detecting coil, under the condition where the output value of said second detected-position signal is the same as the minimum value in the A/D converting range of said second A/D converter, when said movable unit contacts second vertical edge-point which is another of the edge-points of said movement range of said movable unit in said second direction.

11. The method according to claim 10, further comprising storing said optimized coil current-value in a memory unit of said photographing apparatus;

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

12. 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 on a plane which is perpendicular to an optical axis of a camera lens of said photographing apparatus;

a fixed unit that supports said movable unit so as to be movable on said plane, and that has a magnetic-field change-detecting unit for detecting a position of said movable unit on said plane;

a signal-processing unit; and

a control unit that has an A/D converter;

said movable unit having a position-detecting magnetic-field generating unit which is used for detecting said position, and which faces said magnetic-field change-detecting unit, and which has a position-detecting coil;

said position-detecting coil being magnetized by being electrified where an N pole and an S pole are arranged in a direction which is parallel to said optical axis;

said signal-processing unit outputting a detected-position signal, which specifies said position on the basis of an output signal of said magnetic-field change-detecting unit, to said A/D converter;

said control unit calculating said position on the basis of an A/D converting operation by said A/D converter, for said detected-position signal;

an optimized coil current-value being calculated in an initial-adjustment operation which adjusts a detecting-resolution when said detected-position signal is A/D converted by said A/D converter, by changing the value of the current which flows through said position-detecting coil; and

current having said optimized coil current-value, flowing through said position-detecting coil when detecting said position.

13. A method for adjusting a detecting-resolution when A/D converting in an anti-shake apparatus of a photographing apparatus according to claim 12, comprising:

calculating a first coil current-value;

calculating a second coil current-value; and

calculating said optimized coil current-value on the basis of said first and second coil current-values;

said optimized coil current-value being the smaller value of said first and second coil current-values;

said first coil current-value being the value of the current which flows through said position-detecting coil, under the condition where the output value of said 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 edge-point which is one of the edge-points of a movement range of said movable unit; and

said second coil current-value being the value of the current which flows through said position-detecting coil, under the condition where the output value of said 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 edge-point which is another of the edge-points of said movement range of said movable unit.