Optical apparatus

• US 20030161049A1
• Filed: 02/21/2003
• Published: 08/28/2003
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Okada, Tadanori, Horiuchi, Akihisa
• Granted Patent: US 6,924,941 B2
• Time in Patent Office: Days
• US Class Current: 359/696
• CPC Class Codes: G02B 7/102 controlled by a microcomputer cameras with interchangeable lenses G03B17/14
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof
• CPC Class Codes: H04N 23/67 Focus control based on electronic image sensor signals
• CPC Class Codes: H04N 23/69 Control of means for changing angle of the field of view, e.g. optical zoom objectives or electronic zooming
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

An optical apparatus is disclosed which comprises an optical system provided with a zoom lens for performing zooming by moving along the optical axis and a focus lens for performing correction and focusing at the time of zooming, an imaging device for imaging an optical image supplied from the optical system, a zoom actuator for driving the zoom lens, a focus actuator for driving the focus lens, a zoom position detecting device for detecting the position of the zoom lens, a focus position detecting device for detecting the position of the focus lens, an aperture stop member whose opening diameter changes so as to adjust the luminous energy passing through the optical system a filter member to be freely inserted into or extracted from the optical path of the optical system, an aperture stop state detecting device for detecting the opening state of the aperture stop member, a filter state detecting device for detecting the insertion state of the filter member, a memory storing the movement information on the relation between the position of the zoom lens for keeping a focused state and the position of the focus lens, and a control device for correcting the movement information in accordance with an output of the aperture stop state detecting device and an output of the filer state detecting device and controlling driving of the focus lens.

Claims

1. An optical apparatus comprising:

an optical system provided with a zoom lens for performing zooming by moving along the optical axis and a focus lens for performing correction and focusing at the time of zooming;

an image taking device for image taking an optical image supplied from the optical system;

a zoom actuator for driving the zoom lens;

a focus actuator for driving the focus lens;

a zoom position detecting device for detecting the position of the zoom lens;

a focus position detecting device for detecting the position of the focus lens;

an aperture stop member for driving a plurality of aperture stop vanes and thereby changing an opening diameter and the luminous energy of the optical system;

a filter member for changing the luminous energy passing through the opening diameter integrally set to at least one of the aperture stop vanes;

an aperture stop state detecting device for detecting the opening state of the aperture stop member;

a memory storing the movement information on the relation between the position of the zoom lens for keeping a focused state and the position of the focus lens at the time of zoom movement of the zoom lens; and

a control device for correcting the movement information in accordance with an output of the aperture stop state detecting device and controlling driving of the focus lens.

2. The optical apparatus according to claim 1, further comprising:

a correction information memory storing a correction value corresponding to each zoom position of the zoom lens and a correction coefficient corresponding to each aperture stop value of the aperture stop member;

wherein

the control device reads a corresponding correction value and correction coefficient from the correction information memory in accordance with an output of the zoom position detecting device and an output of the aperture stop state detecting device to correct the movement information by using the read correction value and correction coefficient.

3. The optical apparatus according to claim 1, wherein

correction of the movement information is correction of the position of the focus lens, and

when assuming the amount of the above correction as X, the correction amount X satisfies the following conditions by assuming the pixel pitch of an imaging device as P, F number of an aperture stop member as F No., position sensitivity of a focus lens corresponding to the zoom position of a zoom lens as fs, thickness of a filter member on the optical axis as d, and refraction index of the filter member as Nd;

0<

X<

10×

P×

F No/fs10<

d×

P/Nd<

400<

P<

3.5 μ

4. An optical apparatus comprising:

an optical system provided with a zoom lens for performing zooming by moving along the optical axis and a focus lens for performing correction and focusing at the time of zooming;

an image taking device for image taking an optical image supplied from the optical system;

a zoom actuator for driving the zoom lens;

a focus actuator for driving the focus lens;

a zoom position detecting device for detecting the position of the zoom lens;

a focus position detecting device for detecting the position of the focus lens;

an aperture stop member whose opening diameter changes so as to adjust the luminous energy passing through the optical system;

a filter member to be freely inserted into or extracted from the optical path of the optical system;

an aperture stop state detecting device for detecting the opening state of the aperture stop member;

a filter state detecting device for detecting the insertion state of the filter member;

a memory storing the movement information on the relation between the position of the zoom lens for keeping a focused state and the position of the focus lens at the time of zoom movement of the zoom lens; and

a control device for correcting the movement information in accordance with an output of the aperture state detecting device and an output of the filter state detecting device and driving the focus lens.

5. The optical apparatus according to claim 4, further comprising:

a correction information memory storing a correction value corresponding to each zoom position of the zoom lens and a correction coefficient corresponding to the insertion amount of a filter member at each aperture stop value of the aperture stop member;

wherein

the control device reads a corresponding correction value and a corresponding correction coefficient from the correction information memory in accordance with an output of the zoom position detecting device and outputs of the aperture stop state detecting device and the filter state detecting device and corrects the movement information by using the read correction value and correction coefficient.

6. The optical apparatus according to claim 4, wherein

the filter member is driven so that the insertion state of the member is continuously changed to the optical path of the optical system and the member can be freely inserted into or extracted from the optical path.

7. The optical apparatus according to claim 4, wherein

the filter member includes a plurality of filters, and

one or more of the filters is or are selectively inserted or extracted.

8. The optical apparatus according to claim 4, wherein

the filter member includes a plurality of filters having refraction indexes different from each other, and

one or more of the filters is or are selectively inserted or extracted.

9. The optical apparatus according to claim 4, wherein

the correction of the movement information is correction of the position of the focus lens, and

when assuming the correction amount of the position ax X, the correction amount X satisfies the following conditions by assuming the pixel pitch of an imaging device as P, F number of an aperture stop member as F No., position sensitivity of a focus lens corresponding to the zoom position of a zoom lens as fs, thickness of a filter member on an optical axis as d, and refraction index of the filter member as Nd;

10<

X<

10×

P×

F No/fs10<

d×

P/Nd<

400<

P<

3.5 μ

10. An optical apparatus comprising:

an optical system provided with a focus lens;

an image taking device for image taking an optical image supplied from the optical system;

a focus actuator for driving the focus lens;

a focus position detecting device for detecting the position of the focus lens;

an aperture stop member for driving a plurality of aperture stop vanes and thereby changing an opening diameter and the luminous energy of the optical system;

a filter member for changing the luminous energy passing through the opening diameter integrally set to at least one of the aperture stop vanes;

an aperture stop state detecting device for detecting the opening state of the aperture stop member; and

a control device for controlling driving of the focus lens so as to correct the position of the focus lens in accordance with an output of the aperture stop state detecting device.

11. The optical apparatus according to claim 10, further comprising:

a correction information memory storing a preset correction value and a correction coefficient corresponding to each aperture stop value of the aperture stop member;

wherein

the control device reads the preset correction value and a corresponding correction coefficient from the correction information memory in accordance with an output of the aperture stop state detecting device and corrects the position of the focus lens by using the read correction value and correction coefficient.

12. The optical apparatus according to claim 10, wherein

the correction of the movement information is correction of the position of the focus lens, and

when assuming the correction amount of the position as X, the correction amount X satisfies the following conditions by assuming the pixel pitch of an imaging device as P, F number of an aperture stop member as F No., position sensitivity of a focus lens as fs, thickness of a filter member on an optical axis as d, and refraction index of the filter member as Nd;

0<

X<

10×

P×

F No/fs10<

d×

P/Nd<

400<

P<

3.5 μ

13. An optical apparatus comprising:

an optical system provided with a focus lens;

an image taking device for image taking an optical image supplied from the optical system;

a focus actuator for driving the focus lens;

a focus position detecting device for detecting the position of the focus lens;

an aperture stop member whose opening diameter changes so as to adjust the luminous energy passing through the optical system;

a filter member to be freely inserted or extracted into or from the optical path of the optical system so that the insertion state of the member is continuously changed to the optical path;

an aperture stop state detecting device for detecting the opening state of the aperture stop member; and

a filter state detecting device for detecting the insertion state of the filter member;

a control device for controlling driving of the focus lens so as to correct the position of the focus lens in accordance with an output of the aperture stop state detecting device and an output of the filter state detecting device.

14. The optical apparatus according to claim 13, further comprising:

a correction information memory storing a preset correction value and a correction coefficient corresponding to the insertion amount of a filter member at each aperture stop value of the aperture stop member;

wherein

the control device reads the preset correction value and a corresponding correction coefficient from the correction information memory in accordance with outputs of the aperture stop state detecting device and the filter state detecting device and corrects the position of the focus lens by using the read correction value and correction coefficient.

15. The optical apparatus according to claim 13, wherein

the filter member is driven so that the insertion state of the member continuously changes to the optical path of the optical system and the member can be freely inserted into or extracted from the optical path.

16. The optical apparatus according to claim 13, wherein

the filter member includes a plurality of filers, and

one or more of the filters is or are selectively inserted or extracted.

17. The optical apparatus according to claim 13, wherein

the filter member includes a plurality of filters having refraction indexes different from each other, and

one or more of the filters is or are selectively inserted or extracted.

18. The optical apparatus according to claim 13, wherein

the correction of the movement information is correction of the position of the focus lens, and

when assuming the correction amount of the position as X, the correction amount X satisfies the following conditions by assuming the pixel pitch of an imaging device as P, F number of an aperture stop member as F No., position sensitivity of a focus lens as fs, thickness of a filter member on an optical axis as d, and refraction index of the filter member as Nd;

0<

X<

10×

P×

F No/fs

10<

d×

P/Nd<

40

0<

P<

3.5 μ