US4908645A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic focus adjusting device
Assignee: Canon Inc
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Filing: 1989-02-02
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Granted: 1990-03-13
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Expires: 2009-02-02
Abstract
Abstract An automatic focusing device for foreseeing or predicting the position of object after a predetermined time, based on plural past focusing operations on the object, utilizing a function of a higher order, and driving a lens for focusing to the predicted object position. According to the present invention there is provided a correcting circuit for correcting the coefficients of the higher-order function to reduce the influence of the measuring errors contained in the past focusing results, thus constantly enabling appropriate focusing.
Inventors
- 👤 Masaki Higashihara
- 👤 Yasuo Suda
- 👤 Ichiro Ohnuki
- 👤 Akira Akashi
- 👤 Terutake Kadohara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 05:36
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/34
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
94 words
An automatic focusing device for driving a lens according to the output of a focus state detecting circuit, comprising: (a) an operation circuit for determining the amount of lens driving for focusing to an object position after a predetermined time, utilizing a plural-order function and based on past plural focusing data in past plural focusing operations conducted by the focusing device; (b) a driving circuit for driving the lens by the amount of lens driving determined by said operation circuit; and (c) a compensation circuit for correcting a high-order coefficient of said plural-order function.
Claim 2
Dependent Claim
94 words
An automatic focusing device for driving a lens according to the output of a focus state detecting circuit, comprising: (a) an operation circuit for determining the amount of lens driving for focusing to an object position after a predetermined time, utilizing a plural-order function and based on past plural focusing data in past plural focusing operations conducted by the focusing device; (b) a driving circuit for driving the lens by the amount of lens driving determined by said operation circuit; and (c) a compensation circuit for correcting a high-order coefficient of said plural-order function.
Claim 3
Dependent Claim
32 words
An automatic focusing device according to claim 1, wherein said operation circuit is adapted to determine the coefficients to said plural-order function according to the focusing data of past plural focusing operations.
Claim 4
Dependent Claim
60 words
An automatic focusing device according to claim 2, wherein said operation circuit is adapted to determine the image plane position to the object after a predetermined time based on said plural-order function, and to determine the amount of lens driving required for causing the image plane position of the lens to coincide with said image plane position of the object.
Claim 5
Dependent Claim
24 words
An automatic focusing device according to claim 1, wherein said focusing data comprise the amount of defocus detected by the focus state detecting circuit.
Claim 6
Dependent Claim
26 words
An automatic focusing device according to claim 1, wherein said compensation circuit is adapted to correct the coefficient of the highest order in said plural-order function.
Claim 7
Dependent Claim
99 words
An automatic focusing device for driving a lens according to the output of a focus state detecting circuit, comprising: (a) an operation circuit for determining the amount of lens driving for focusing to an object position after a predetermined time, utilizing a plural-order function and based on past plural focusing data in past plural focusing operations conducted by the focusing device; (b) a driving circuit for driving the lens by the amount of lens driving determined by said operation circuit; and (c) a compensation circuit for correcting a high-order coefficient of said plural-order function according to said focusing data.
Claim 8
Dependent Claim
99 words
An automatic focusing device for driving a lens according to the output of a focus state detecting circuit, comprising: (a) an operation circuit for determining the amount of lens driving for focusing to an object position after a predetermined time, utilizing a plural-order function and based on past plural focusing data in past plural focusing operations conducted by the focusing device; (b) a driving circuit for driving the lens by the amount of lens driving determined by said operation circuit; and (c) a compensation circuit for correcting a high-order coefficient of said plural-order function according to said focusing data.
Claim 9
Dependent Claim
32 words
An automatic focusing device according to claim 6, wherein said compensation circuit is adapted to correct said high-order coefficient, according to the amount of defocus determined by the focus state detecting circuit.
Claim 10
Dependent Claim
27 words
An automatic focusing device according to claim 6, wherein said compensation circuit is adapted to correct said high-order coefficient according to the amount of past lens driving.
Claim 11
Dependent Claim
20 words
An automatic focusing device according to claim 8, wherein said amount of lens driving is determined by said operation circuit.
Claim 12
Dependent Claim
32 words
An automatic focusing device according to claim 6, wherein said operation circuit is adapted to determine the coefficients of said plural-order function according to the focusing data of past plural focusing operations.
Claim 13
Dependent Claim
60 words
An automatic focusing device according to claim 10, wherein said operation circuit is adapted to determine the image plane position of the object after a predetermined time based on said plural-order function, and to determine the amount of lens driving required for causing the image plane position of the lens to coincide with said image plane position of the object.
Claim 14
Dependent Claim
26 words
An automatic focusing device according to claim 6, wherein said compensation circuit is adapted to correct the coefficient of the highest order in said plural-order function.
Claim 15
Dependent Claim
32 words
An automatic focusing device according to claim 7, wherein said operation circuit is adapted to determine the coefficients of said plural-order function according to the focusing data of past plural focusing operations.
Claim 16
Dependent Claim
60 words
An automatic focusing device according to claim 13, wherein said operation circuit is adapted to determine the image plane position of the object after a predetermined time based on said plural-order function, and to determine the amount of lens driving required for causing the image plane position of the lens to coincide with said image plane position of the object.
Claim 17
Dependent Claim
24 words
An automatic focusing device according to claim 7, wherein said focusing data comprise the amount of defocus detected by the focus state detecting circuit.
Claim 18
Dependent Claim
32 words
An automatic focusing device according to claim 8, wherein said operation circuit is adapted to determine the coefficients of said plural-order function according to the focusing data of past plural focusing operations.
Claim 19
Dependent Claim
60 words
An automatic focusing device according to claim 16, wherein said operation circuit is adapted to determine the image plane position of the object after a predetermined time based on said plural-order function, and to determine the amount of lens driving required for causing the image plane position of the lens to coincide with said image plane position of the object.
Claim 20
Dependent Claim
24 words
An automatic focusing device according to claim 8, wherein said focusing data comprise the amount of defocus detected by the focus state detecting citcuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-03-12 | 1993-09-11 | 1994-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-12 | 1997-09-11 | 1998-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-12 | 2001-09-11 | 2002-03-13 | $7700.00 | Window Closed / Lapsed |