Lens control device and lens control method

Patent metadata

Field	Value
Publication number	US-11906894-B2
Application number	US-202217579533-A
Country	US
Kind code	B2
Filing date	Jan 19, 2022
Priority date	Jul 26, 2019
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

A lens control device, comprising a first stepping motor that drives a zoom lens contained in the photographing lens, a second stepping motor that drives a focus lens contained in the photographing lens, and a processor that controls the first stepping motor and the second stepping motor, whereby, within a given section in which the zoom lens and the focus lens are driven, there is a period in which at least one of the first stepping motor and the second stepping motor is driven at a constant rate, and the processor makes a time, required to move the specified section with a specified number of pulses, a specified time.

First claim

What is claimed is:

1. A lens control device having a photographing lens that is capable of zoom and focus, comprising:
a first stepping motor that drives a zoom lens contained in the photographing lens;
a second stepping motor that drives a focus lens contained in the photographing lens; and
a processor that is capable of setting drive times in accordance with a specified control unit time for each of respective drive pulses of the first stepping motor and the second stepping motor, and that controls the first stepping motor and the second stepping motor, whereby
within a given section in which the zoom lens and the focus lens are driven, there is a period in which at least one of the first stepping motor and the second stepping motor is driven at a constant rate, and
the processor, in order to make a time, required to drive at least one of the first stepping motor and the second stepping motor by a specified number of drive pulses during the period in which there is drive at the constant rate, match a specified time,
when a drive time per one drive pulse, that has been derived by dividing drive time for all drive pulses of a period in which there is drive at the constant rate by the specified number of drive pulses, is made average drive time,
divides the period in which there is drive at the constant rate into a plurality of per ids, calculates two of the drive times that are different from each other by the control unit time, on either side of the average drive time, and sets one of the two drive times, that are different from each other by the control unit time, as a drive time for every drive pulse of the plurality of periods.

2. The lens control device of claim 1 , further comprising a memory, wherein;
specified reference times corresponding to respective sections, where a range in which zoom position of the zoom lens can be changed has been divided into a plurality of sections, are stored in the memory; and
the processor reads out the specified reference time corresponding to the specified section, among the plurality of sections, and calculates the time required to drive at least one of the first stepping motor and the second stepping motor by a specified number of drive pulses during the period in which there is drive at the constant rate, by subtracting a time required for acceleration and deceleration of the first stepping motor and the second stepping motor from the specified reference time that has ben read out.

3. The lens control device of claim 2 , wherein;
section pulse values corresponding to respective sections, where a range in which zoom position of the zoom lens can be changed has been divided into a plurality of sections, are stored in the memory; and
the processor reads out the section pulse value corresponding to the specified section, among the plurality of sections, and calculates the specified number of drive pulses by subtracting a number of drive pulses required for acceleration and deceleration of the first stepping motor and the second stepping motor from the section pulse value that has been read out.

4. The lens control device of claim 1 , further comprising:
a third stepping motor that drives a second zoom lens contained in the photographing lens; and wherein
there is a period in which at least one of the first stepping motor, second stepping motor, and third stepping motor are driven at a constant rate,
in order to make a time, required to move by a specified number of drive pulses in a period in which the zoom lens, the focus lens and the second zoom lens are driven at a constant rate, match a predetermined time, the period in which there is drive at the constant rate is divided into a plurality of periods, and one of two drive times on either side of the average time, that are different from each other by the control unit time, is set.

5. The lens control device of claim 1 , wherein:
the processor sets one drive time, of the two drive times on either side of the average drive time, to the drive pulses for first period that has continuous drive pulses among the plurality of periods, and sets the other drive time to drive pulses for second period that has continuous drive pulses among the plurality of periods.

6. The lens control device of claim 1 , wherein:
the processor sets one drive time, of the two drive times on either side of the average drive time, to the drive pulses for first periods that are dispersed among the plurality of periods, and sets the other drive time to drive pulses for second periods that are dispersed among the plurality of periods.

7. A lens control method for an imaging device that comprises a photographing lens that is capable of zoom and focus, a first stepping motor that drives a zoom lens contained in the photographing lens, and a second stepping motor that drives a focus lens contained in the photographing lens, comprising:
being able to set drive times in accordance with a specified control unit time tor each of respective drive pulse of the first stepping motor and the second stepping motor, and, when controlling the first stepping motor and the second stepping motor,
within a given section in which the zoom lens and the focus lens are driven, having a period in which at least one of the first stepping motor and the second stepping motor is driven at a constant rate, and,
in order to make a time, required to drive at least one of the first stepping motor and the second stepping motor by a specified number of drive pulses during the period in which there is drive at the constant rate, match a specified time,
when a drive time per one drive pulse, that has been derived by dividing drive time for all drive pulses of a period in which there is drive at the constant rate by the specified number of drive pulses, is made average drive time,
dividing the period in which there is drive at the constant rate into a plurality of periods, calculating two of the drive times that are different from each other by the control unit time, on either side of the average drive time, and setting one of the two drive times, that are different from each other by the control unit time, as a drive time for every drive pulse of the plurality of periods.

8. The lens control method of claim 7 , further comprising:
dividing a range in which zoom position of the zoom lens can be changed into a plurality of sections,
storing specified reference times corresponding to respective sections in a memory,
reading out the specified reference time corresponding to the specified sect ion, among the plurality of sections, and
respectively calculating the time required to drive at least one of the first stepping motor and the second stepping motor by a specified number of drive pulses during the period in which there is drive at the constant rate, by subtracting a time required for acceleration and deceleration of the first stepping motor and the second stepping motor from the specified reference time that has been read out.

9. The lens control method of claim 8 , further comprising:
extending the specified time to a shortest time, that exceeds the specified reference time.

10. The lens control method of claim 7 , wherein the imaging device further comprises a third stepping motor for driving a second zoom lens contained in the photographing lens, wherein:
there is a period in which at least one of the first stepping motor, second stepping motor, and third stepping motor are driven at a constant rate,
and the method further comprises setting a time or the period, in order to make a time, required to move by a specified number of drive pulses in a period in which the zoom lens, the focus lens and the second zoom lens are driven at a constant rate, match a predet

Assignees

• Olympus Corp

Inventors

• Kudo Yasunori

Classifications

• G03B5/04 Primary

  Vertical adjustment of lens; Rising fronts · CPC title

• H02P8/14

  Arrangements for controlling speed or speed and torque (H02P8/12, H02P8/22 take precedence) · CPC title

• G03B2205/0084

  using other types of actuators · CPC title

• H02P8/40 Primary

  Special adaptations for controlling two or more stepping motors · CPC title

• G02B7/08

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