Camera shake correction apparatus

Patent metadata

Field	Value
Publication number	US-9742257-B2
Application number	US-201615083175-A
Country	US
Kind code	B2
Filing date	Mar 28, 2016
Priority date	Jun 11, 2015
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

A camera shake correction apparatus includes a target position setting unit, a current setting unit, a driving unit, a magnetic flux detector, and an arithmetic unit. The target position setting unit sets a target position of a movable member. The current setting unit sets a current value to move the movable member to the target position. The driving unit drives the movable member with respect to a fixed member based on the set current set value. The magnetic flux detector detects a magnetic flux value changed with movement of the movable member. The arithmetic unit calculates a third magnetic flux value by subtracting a second magnetic flux value estimated to be generated from the driving unit based on the current set value from a first magnetic flux value actually detected by the magnetic flux detector.

First claim

What is claimed is:

1. A camera shake correction apparatus driving a movable member including an optical member or an imaging member with respect to a fixed member, based on a detected camera shake amount, comprising:
a target position setting unit setting a target position to which the movable member is to be moved based on the camera shake amount;
a current setting unit setting a current value to move the movable member to the target position;
a driving unit formed of a coil disposed in one of the movable member and the fixed member, and a magnet disposed in the other of the movable member and the fixed member and used for detecting a position of the movable member and driving the movable member, the driving unit driving the movable member with respect to the fixed member based on the set current set value;
a magnetic flux detector detecting a magnetic flux value changed with movement of the movable member when the movable member is actually driven by the driving unit; and
an arithmetic unit calculating a third magnetic flux value by subtracting a second magnetic flux value estimated to be generated from the driving unit based on the current set value from a first magnetic flux value actually detected by the magnetic flux detector, when the set current set value belongs to a nonlinear region,
wherein the arithmetic unit updates the current set value to move the movable member to the target position to a second current set value corresponding to the third magnetic flux value, and the driving unit drives the movable member based on the second current set value.

2. The camera shake correction apparatus according to claim 1 , wherein the arithmetic unit includes a storage unit storing in advance the relationship between a current flowing through the coil and the current set value, and estimates the second magnetic flux value based on data stored in advance in the storage unit.

3. The camera shake correction apparatus according to claim 2 , wherein the arithmetic unit includes a determination unit determining whether the set current set value belongs to the nonlinear region, and the determination unit determines that a region in which one of a current set value or a current value is 0 and the other of the current set value or the current value is not 0 is the nonlinear region.

4. The camera shake correction apparatus according to claim 1 , wherein the arithmetic unit calculates a current estimation curve in which the relationship between a current flowing through the coil and the current set value changes linearly in the nonlinear region, and determines the third magnetic flux value based on the current estimation curve.

5. A camera shake correction apparatus driving a movable member including an optical member or an imaging member with respect to a fixed member, based on a detected camera shake amount, comprising:
a target position setting unit setting a target position to which the movable member is to be moved based on the camera shake amount;
a current setting unit setting a current set value to move the movable member to the target position;
a driving unit driving a voice coil motor formed driving coil disposed in one of the movable member and the fixed member and a magnet disposed in the other of the movable member and the fixed member and used for detecting a position of the movable member and driving the movable member, based on the current set value, and thereby moving the movable member with respect to the fixed member;
a magnetic flux detector detecting a magnetic flux value changed with movement of the movable member by the driving unit;
an arithmetic unit calculating a third magnetic flux value by subtracting a second magnetic flux value estimated to be generated based on a current value flowing through the driving coil from a first magnetic flux value actually detected by the magnetic flux detector, when the current set value belongs to a nonlinear region in which the relationship of a magnetic flux value to the current set value is nonlinear; and
a position calculator calculating a present position of the movable member from the third magnetic flux value,
wherein the current setting unit sets the current set value based on the target position and the present position.

6. The camera shake correction apparatus according to claim 5 , wherein the arithmetic unit includes a storage unit storing in advance the relationship between the current set value and the second magnetic flux value, and estimates the second magnetic flux value based on the relationship stored in advance in the storage unit.

7. The camera shake correction apparatus according to claim 6 , wherein the arithmetic unit includes a determination unit determining whether the current set value belongs to the nonlinear region, and the determination unit determines that a region in which a current flowing through the driving coil is 0 for the current set value that is not 0 is the nonlinear region.

8. The camera shake correction apparatus according to claim 6 , wherein the arithmetic unit calculates an estimation curve indicating the relationship between the current set value and the second magnetic flux value, and determines the third magnetic flux value based on the estimation curve, when the current set value belongs to the nonlinear region.

Assignees

• Olympus Corp

Inventors

• Shimoyama Masanori

Classifications

• H04N23/687

  by shifting the lens or sensor position · CPC title

• G03B2205/0038

  by displacing the image plane with respect to the optical axis · CPC title

• H02K41/0354

  Lorentz force motors, e.g. voice coil motors · CPC title

• G03B2205/0069

  using electromagnetic actuators, e.g. voice coils · CPC title

• G03B5/00 Primary

  Adjustment of optical system relative to image or object surface other than for focusing · CPC title