Lens control device and lens control method

Patent metadata

Field	Value
Publication number	US-10564386-B2
Application number	US-201715429786-A
Country	US
Kind code	B2
Filing date	Feb 10, 2017
Priority date	Feb 23, 2016
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

A lens control device that moves a lens in an optical axis direction comprises a stepping motor that drives the lens, a position detection circuit that detects position of the lens in an optical axis direction, a memory that stores data relating to a relationship between rotational position of the stepping motor and detected position of the position detection circuit, and a controller that designates rotational position of the stepping motor based on target information that is input, determines a virtual target rotational position based on a target position corresponding to detected position of the position detection circuit corresponding to the target information that has been input, and, based on the virtual target rotational position, searches for a rotational position that corresponds to the target position, within a range of given rotational positions of the data.

First claim

What is claimed is:

1. A lens control device that moves a lens in an optical axis direction, comprising:
a stepping motor that drives the lens,
a position detection circuit that detects a position signal corresponding to position of the lens in an optical axis direction,
a memory that stores data relating to a relationship between rotational position of the stepping motor and detected position of the position detection circuit, and
a controller that designates rotational position of the stepping motor based on target information that is input, determines a virtual target rotational position based on a target position corresponding to detected position of the position detection circuit corresponding to the target information that has been input, and, based on the virtual target rotational position, retrieves a rotational position that corresponds to the target position, within a given range of rotational position of the data, without driving the stepping motor, wherein:
the controller calculates a detected position for a case in which rotational position is offset by a given offset amount from the virtual target rotational position based on the data, and either (A) retrieves a rotational position at which the detected position calculated coincides with the target position, or (B) retrieves a rotational position at which a difference between the calculated detected position and the target position is minimum, within a given range of rotational position of the data.

2. The lens control device of claim 1 , wherein:
the given range of rotational position corresponds to one cycle of an electric angle of the stepping motor.

3. The lens control device of claim 1 , wherein:
the controller determines virtual target rotational position based on target position corresponding to detection position of the position detection section, based on reference data in a relationship in which a relationship between rotational position of the stepping motor and detected position of the position detection circuit constitutes a reference.

4. A lens control method for a lens control device having a stepping motor that moves the lens in an optical axis direction, a position detection circuit that detects position of the lens in an optical axis direction, and a memory that stores data relating to a relationship between rotational position of the stepping motor and detected position of the position detection circuit, comprising:
determining a virtual target rotational position based on a target position that corresponds to detected position of the position detection circuit corresponding to target information that has been input,
retrieving rotational position corresponding to the target position, based on the virtual target rotational position, within a given range of rotational position of the data without driving the stepping motor, and
instructing rotational position of the stepping motor based in the retrieved rotational position, further comprising:
calculating a detected position for a case where rotational position is offset by a given offset amount from the virtual target rotational position based on the data, and either (A) retrieving a rotational position at which the detected position calculated coincides with the target position, or (B) retrieving a rotational position at which a difference between the calculated detected position and the target position is minimum, within a given range of rotational position of the data.

5. The lens control method of claim 4 , wherein:
the given range of rotational position corresponds to one cycle of an electric angle of the stepping motor.

6. The lens control method of claim 4 , further comprising:
determining virtual target rotational position based on target position corresponding to a detection position, based on reference data using a relationship between rotational position of the stepping motor and detected position as a reference.

7. A non-transitory computer-readable medium storing a processor executable code, which, when executed by at least one processor, performs a lens control method for a lens control device, which includes a stepping motor that moves the lens in an optical axis direction, a position detection circuit that detects position of the lens in an optical axis direction, and a memory that stores data relating to a relationship between rotational position of the stepping motor and detected position of the position detection circuit, the lens control method comprising:
determining a virtual target rotational position based on a target position that corresponds to detected position of the position detection circuit corresponding to target information that has been input,
retrieving rotational position corresponding to the target position, based on the virtual target rotational position, within a given range of rotational position of the data, without driving the stepping motor, and
instructing rotational position of the stepping motor based in the retrieved rotational position, further comprising:
calculating a detected position for a case where rotational position is offset by a given offset amount from the virtual target rotational position based on the data, and either (A) retrieving a rotational position at which the detected position calculated coincides with the target position, or (B) retrieving a rotational position at which a difference between the calculated detected position and the target position is minimum, within a given range of rotational position of the data.

8. The non-transitory computer-readable medium of claim 7 , wherein:
the given range of rotational position corresponds to one cycle of an electric angle of the stepping motor.

9. The non-transitory computer-readable medium of claim 7 , further comprising:
determining virtual target rotational position based on target position corresponding to detection position of the position detection section, based on reference data in a relationship in which a relationship between rotational position of the stepping motor and detected position of the position detection circuit constitutes a reference.

Assignees

• Olympus Corp

Inventors

• Nakamura Makoto

Classifications

• G02B7/09 Primary

  adapted for automatic focusing or varying magnification · CPC title

• G02B7/08

  adapted to co-operate with a remote control mechanism · CPC title

• H02K37/24

  Structural association with auxiliary mechanical devices · CPC title

• H02K7/06

  Means for converting reciprocating motion into rotary motion or vice versa · CPC title

• G02B7/04 Primary

  with mechanism for focusing or varying magnification · CPC title