Patent US5140357A successfully refreshed from Google Patents.
US5140357A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic focusing device wherein loop gain is set responsively to variation of magnification
Assignee: Canon Inc
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Filing: 1990-12-12
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Granted: 1992-08-18
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Expires: 2010-12-12
Abstract
Abstract An automatic focus adjusting device comprising extracting circuitry for extracting a focus signal from an image sensor corresponding to the degree of focusing of an image sensing signal output from the sensor, a drive device for adjusting focus so as to bring an optical system into a focuses state on the basis of the focus signal and a control unit operative to detect a magnification varying operation of the optical system for controlling a loop gain of a closed loop encompassing the image sensor, the extracting circuitry and the drive device.
Inventors
- 👤 Hirofumi Suda
- 👤 Hideyuki Arai
- 👤 Kitahiro Kaneda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:09
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/282
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
102 words
An automatic focus adjusting device comprising: (a) extracting means for extracting a focus signal corresponding to the degree of focusing from an image sensing signal output from the image sensing means; (b) drive means for adjusting focus so as to bring an optical system into an in-focus state on the basis of said focus signal; and (c) control means, arranged to detect a magnification varying operation of said optical system, for controlling a loop gain of a closed loop composed of said image sensing means, said extracting means and said drive means in response to the detection of the magnification varying operation.
Claim 2
Dependent Claim
102 words
An automatic focus adjusting device comprising: (a) extracting means for extracting a focus signal corresponding to the degree of focusing from an image sensing signal output from the image sensing means; (b) drive means for adjusting focus so as to bring an optical system into an in-focus state on the basis of said focus signal; and (c) control means, arranged to detect a magnification varying operation of said optical system, for controlling a loop gain of a closed loop composed of said image sensing means, said extracting means and said drive means in response to the detection of the magnification varying operation.
Claim 3
Dependent Claim
19 words
A device according to claim 1, wherein said extracting means extracts a high-frequency component from said image sensing signal.
Claim 4
Dependent Claim
28 words
A device according to claim 1, wherein said control means varies the loop gain to control a driving characteristic of said drive means for driving said optical system.
Claim 5
Dependent Claim
30 words
A device according to claim 3, wherein said control means, when the magnification varying operation is carried out from a wide-angle side to a telephoto side, increases the loop gain.
Claim 6
Dependent Claim
34 words
A device according to claim 3, wherein said control means, when the magnification varying operation is carried out from a wide-angle side to a telephoto side, increases a driving speed of said drive means.
Claim 7
Dependent Claim
17 words
A device according to claim 1, wherein said magnification varying operation is detected by a zoom encoder.
Claim 8
Dependent Claim
21 words
A device according to claim 1, wherein said magnification varying operation is detected by an operation of a zooming operation switch.
Claim 9
Dependent Claim
120 words
An automatic focus adjusting device comprising: (a) modulating means for periodically varying an image forming state of an image sensing plane; (b) extracting means for extracting a signal responding to said modulating means and corresponding to the degree of focusing from an image sensing signal output from image sensing means; (e) drive means for moving an optical system to an in-focus point on the basis of the signal extracted by said extracting means; and (d) control means, arranged to detect a magnification varying operation of said optical system, for controlling a loop gain of a closed loop composed of said image sensing means, said extracting means and said drive means in response to the detection of the magnification varying operation.
Claim 10
Dependent Claim
120 words
An automatic focus adjusting device comprising: (a) modulating means for periodically varying an image forming state of an image sensing plane; (b) extracting means for extracting a signal responding to said modulating means and corresponding to the degree of focusing from an image sensing signal output from image sensing means; (e) drive means for moving an optical system to an in-focus point on the basis of the signal extracted by said extracting means; and (d) control means, arranged to detect a magnification varying operation of said optical system, for controlling a loop gain of a closed loop composed of said image sensing means, said extracting means and said drive means in response to the detection of the magnification varying operation.
Claim 11
Dependent Claim
35 words
A device according to claim 8, wherein said modulating means vibrates said image sensing means or a focusing lens back and forth in axial directions in a predetermined period to modulate said image sensing signal.
Claim 12
Dependent Claim
37 words
A device according to claim 8, wherein said extracting means extracts a high-frequency component which has been modulated from said image sensing signal, and extracts an amount of variation of the high-frequency component which has been modulated.
Claim 13
Dependent Claim
40 words
A device according to claim 10, wherein said extracting means extracts said high-frequency component from a portion of the image sensing signal which is obtained from a focus detecting area formed in a predetermined position on the image sensing plane.
Claim 14
Dependent Claim
26 words
A device according to claim 8, wherein said control means varies an amplitude of vibration of said modulating means in accordance with the magnification varying operation.
Claim 15
Dependent Claim
30 words
A device according to claim 8, wherein said control means, when the magnification varying operation is carried out from a wide-angle side to a telephoto side, increases the loop gain.
Claim 16
Dependent Claim
34 words
A device according to claim 8, wherein said control means, when the magnification varying operation is carried out from a wide-angle side to a telephoto side, increases a driving speed of said drive means.
Claim 17
Dependent Claim
19 words
A device according to claim 12, wherein said control means detects said magnification varying operation from a zoom encoder.
Claim 18
Dependent Claim
23 words
A device according to claim 12, wherein said control means detects said magnification varying operation by an operation of a zooming operation switch.
Claim 19
Dependent Claim
116 words
An automatic focus adjusting device comprising: (a) extracting means for extracting a focus signal corresponding to the degree of focusing from an image sensing signal output from image sensing means; (b) modulating means for modulating said focus signal by a predetermined frequency; (c) drive means for moving a focusing lens to an in-focus point on the basis of a signal obtained by demodulating a modulation component of said focus signal modulated by said modulating means; and (d) control means, arranged to detect a magnification varying operation being carried out from a wide-angle side to a telephoto side, for varying a drive characteristic of said focusing lens in response to the detection of the magnification varying operation.
Claim 20
Dependent Claim
116 words
An automatic focus adjusting device comprising: (a) extracting means for extracting a focus signal corresponding to the degree of focusing from an image sensing signal output from image sensing means; (b) modulating means for modulating said focus signal by a predetermined frequency; (c) drive means for moving a focusing lens to an in-focus point on the basis of a signal obtained by demodulating a modulation component of said focus signal modulated by said modulating means; and (d) control means, arranged to detect a magnification varying operation being carried out from a wide-angle side to a telephoto side, for varying a drive characteristic of said focusing lens in response to the detection of the magnification varying operation.
Claim 21
Dependent Claim
17 words
A device according to claim 17, wherein said control means increases the responsiveness of said focusing lens.
Claim 22
Dependent Claim
39 words
A device according to claim 17, wherein said magnification varying operation is detected by an operation of a zooming operation switch or a zoom encoder, and wherein said control means increases he amount of modulation of said modulating means.
Claim 23
Dependent Claim
38 words
A device according to claim 17, wherein said magnification varying operation is detected by an operation of a zooming operation switch or a zoom encoder, and wherein said control means increases a drive gain of said focusing lens.
References Cited (Backward Citations)
US4920420A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-18 | 1996-02-17 | 1996-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-18 | 2000-02-17 | 2000-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-18 | 2004-02-17 | 2004-08-18 | $7700.00 | Window Closed / Lapsed |