US5157434A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Autofocusing system for camera
Assignee: Pentax Corp
•
Filing: 1991-05-08
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Granted: 1992-10-20
•
Expires: 2011-05-08
Abstract
Abstract An autofocusing system for a camera, wherein a defocus amount is detected with a light-amount-integration type detector for performing a focusing operation. The focusing operation is adjusted in a predetermined fashion if it is determined that a photographic lens has moved and/or the focal length of the photographic lens has varied while the light-amount-integration is being executed.
Inventors
- 👤 Noboru Suzuki
- 👤 Shigeo Toji
- 👤 Masahiro Kawasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 06:32
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
77 words
A focusing detection system for a camera, comprising: means for obtaining a focal length of a photographic lens used with said focusing detection system; means for obtaining a forefront Kval value Kh; means for obtaining a Fval correction value Kc; means for obtaining a forefront number of pulses Ph corresponding to one zoom code zone; means for obtaining an absolute number of pulses Ps; and means for calculating a change of Kval according to an equation: Kval=Kh+Kc·(Ps-Ph).
Claim 2
Dependent Claim
77 words
A focusing detection system for a camera, comprising: means for obtaining a focal length of a photographic lens used with said focusing detection system; means for obtaining a forefront Kval value Kh; means for obtaining a Fval correction value Kc; means for obtaining a forefront number of pulses Ph corresponding to one zoom code zone; means for obtaining an absolute number of pulses Ps; and means for calculating a change of Kval according to an equation: Kval=Kh+Kc·(Ps-Ph).
Claim 3
Dependent Claim
44 words
The focusing detection system of claim 1, wherein said means for obtaining said absolute number of pulses Ps comprises means for counting a number of pulses which are produced when said photographic lens is moved from a wide extremity to a predetermined zoom setting.
Claim 4
Dependent Claim
23 words
The focusing detection system of claim 2, wherein a motor moves said photographic lens between said wide extremity and said predetermined zooming setting.
Claim 5
Dependent Claim
36 words
The focusing detection system of claim 1, wherein a ROM associated with said photographic lens is read to obtain said forefront Kval value Kh, said Kval correction factor Kc and said forefront number of pulses Ph.
Claim 6
Dependent Claim
112 words
A focusing system for a camera, comprising: means for detecting a focal length of a photographic lens associated with said camera; means for outputting a conversion factor for converting a defocus amount into an amount to shift said photographic lens in compliance with an output of said focal length detecting means; means for calculating said conversion factor from an output of said conversion factor outputting means during a predetermined period of time; means for determining whether said photographic lens has shifted while said conversion factor calculating means is calculating said conversion factor; and means for calculating said amount to shift said photographic lens from said output of said conversion factor outputting means.
Claim 7
Dependent Claim
112 words
A focusing system for a camera, comprising: means for detecting a focal length of a photographic lens associated with said camera; means for outputting a conversion factor for converting a defocus amount into an amount to shift said photographic lens in compliance with an output of said focal length detecting means; means for calculating said conversion factor from an output of said conversion factor outputting means during a predetermined period of time; means for determining whether said photographic lens has shifted while said conversion factor calculating means is calculating said conversion factor; and means for calculating said amount to shift said photographic lens from said output of said conversion factor outputting means.
Claim 8
Dependent Claim
13 words
The focusing system of claim 5, wherein said camera comprises an autofocus camera.
Claim 9
Dependent Claim
29 words
The focusing system of claim 5, wherein said predetermined period of time comprises a period of time from when a light-amount-integration starts to a time when said light-amount-integration terminates.
Claim 10
Dependent Claim
40 words
The focusing system of claim 5, wherein said shift amount calculating means calculates said shift amount at a time when a light-amount-integration terminates and said defocus amount if said determining means determines that said photographic lens has not been shifted.
Claim 11
Dependent Claim
45 words
The focusing system of claim 5, wherein said shift amount calculating means calculates said shift amount of said photographic lens from said conversion factor computed by said factor calculation means and said defocus amount if said determining means determines that said photographic lens has shifted.
Claim 12
Dependent Claim
42 words
The focusing system of claim 5, wherein said conversion factor calculating means compensates said conversion factor in accordance with a direction of change of said focal length of said photographic lens if said focal length varies while a light-amount-integration is being executed.
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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) | 1995-10-20 | 1996-04-20 | 1996-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-10-20 | 2000-04-20 | 2000-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-10-20 | 2004-04-20 | 2004-10-20 | $7700.00 | Window Closed / Lapsed |