US5664239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic focusing apparatus
Assignee: Hoya Corp
•
Filing: 1995-06-06
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Granted: 1997-09-02
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Expires: 2015-06-06
Abstract
Abstract A focus detecting apparatus that includes an optical system having a group of focusing lenses. An object distance measuring device measures a defocus amount for a specific object imaged by the optical system. A focus judging device determines a focus state in accordance with a measurement of the object distance measuring device. A lens driver then drives the focusing lens group to a focal position, in accordance with the amount of defocus, wherein the apparatus includes a controller for repeatedly operating the object distance measuring device and the lens driver. A moving object judging device determines that the specific object is a moving object when the focus judging device determines an out-of-focus state more than one time during the repeated operations.
Inventors
- 👤 Masahiro Nakata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 05:29
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
129 words
A focus detecting apparatus that includes an optical system having a group of focusing lenses, and means for measuring a defocus amount for an image of a specific object formed by said focusing lens group, comprising: means for determining a contrast of said image of said specific object; and means for selecting a defocus amount such that, when said contrast determining means determines that said contrast of said specific object image is not low, said measured defocus amount is selected, and when said contrast determining means determines that said contrast of said specific object defocus amount is low, said defocus amount measuring means operates to re-measure said defocus amount, so that said re-measured defocus amount is compared with a previously obtained defocus amount to select a smaller defocus amount.
Claim 2
Dependent Claim
129 words
A focus detecting apparatus that includes an optical system having a group of focusing lenses, and means for measuring a defocus amount for an image of a specific object formed by said focusing lens group, comprising: means for determining a contrast of said image of said specific object; and means for selecting a defocus amount such that, when said contrast determining means determines that said contrast of said specific object image is not low, said measured defocus amount is selected, and when said contrast determining means determines that said contrast of said specific object defocus amount is low, said defocus amount measuring means operates to re-measure said defocus amount, so that said re-measured defocus amount is compared with a previously obtained defocus amount to select a smaller defocus amount.
Claim 3
Dependent Claim
19 words
The focus detecting apparatus of claim 1, wherein said defocus amount measuring means comprises a phase difference detecting sensor.
Claim 4
Dependent Claim
29 words
The focus detecting apparatus of claim 2, further comprising means for driving said focusing lens group in accordance with said defocus amount selected by said defocus amount selecting means.
Claim 5
Dependent Claim
59 words
The focus detecting apparatus of claim 3, further comprising means for determining whether said specific object is in-focus, in accordance with said defocus amount measured by said defocus amount measuring means, so that said defocus amount selecting means selects said measured defocus amount regardless of said contrast when said focus determining means determines that said specific object is in-focus.
Claim 6
Dependent Claim
29 words
The focus detecting apparatus of claim 4, further comprising means for driving said focusing lens group in accordance with said defocus amount selected by said defocus amount selecting means.
Claim 7
Dependent Claim
28 words
The focus detecting apparatus of claim 5, further comprising an indicator that indicates said in-focus state when said focus determining means determines that said specific object is in-focus.
Claim 8
Dependent Claim
119 words
A focus detecting apparatus that includes an optical system having a group of focusing lenses, measuring device that measures a defocus amount for an image of a specific object formed by said focusing lens group, comprising: a contrast device that determines a contrast of said image of said specific object; and a selecting device that: selects said measured defocus amount when said contrast device determines that said contrast of said specific object image is not low; and re-measures said defocus amount so that said re-measured defocus amount is compared with a previously obtained defocus amount in order to select a smaller defocus amount when said contrast device determines that said contrast of said specific object defocus amount is low.
Claim 9
Dependent Claim
119 words
A focus detecting apparatus that includes an optical system having a group of focusing lenses, measuring device that measures a defocus amount for an image of a specific object formed by said focusing lens group, comprising: a contrast device that determines a contrast of said image of said specific object; and a selecting device that: selects said measured defocus amount when said contrast device determines that said contrast of said specific object image is not low; and re-measures said defocus amount so that said re-measured defocus amount is compared with a previously obtained defocus amount in order to select a smaller defocus amount when said contrast device determines that said contrast of said specific object defocus amount is low.
Claim 10
Dependent Claim
17 words
The focus detecting apparatus of claim 7, wherein said measuring device comprise a phase difference detecting sensor.
Claim 11
Dependent Claim
29 words
The focus detecting apparatus of claim 8, further comprising a lens driver that drives said focusing lens group in accordance with said defocus amount selected by said selecting device.
Claim 12
Dependent Claim
28 words
The focus detecting apparatus of claim 9, further comprising an indicator that indicates when said focusing lens group is driven to an in-focus state by said lens driver.
References Cited (Backward Citations)
JPS5859416A
Cited
US4537487A
Cited
US4550995A
Cited
JPS60214325A
Cited
JPS61165716A
Cited
US4860045A
Cited
US4967224A
Cited
US4969006A
Cited
US5040015A
Cited
US4816856A
Cited
US4924250A
Cited
US4783677A
Cited
US4800410A
Cited
US4980715A
Cited
US4952962A
Cited
US4868592A
Cited
US5008605A
Cited
EP0298486A2
Cited
US5012267A
Cited
US4908647A
Cited
EP0349736A2
Cited
EP0347042A1
Cited
US4988856A
Cited
US5005039A
Cited
US5065175A
Cited
US5157434A
Cited
US5036349A
Cited
EP0364137A2
Cited
US5066968A
Cited
GB2224126A
Cited
EP0382143A2
Cited
JPH03289775A
Cited
GB2250828A
Cited
US5276476A
Cited
US5291235A
Cited
US5321459A
Cited
US5359382A
Cited
US5416559A
Cited
US5448329A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-09-01 | 2001-03-03 | 2001-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-09-01 | 2005-03-03 | 2005-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-09-01 | 2009-03-03 | 2009-09-02 | $7700.00 | Window Closed / Lapsed |