US4327284A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Focusing detection device
Assignee: Ricoh Co Ltd
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Filing: 1980-03-12
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Granted: 1982-04-27
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Expires: 2000-03-12
Abstract
Abstract A focusing detection device is disclosed wherein an electric output obtained by sequentially driving a group of photoelectric elements disposed adjacent to one another on an imaging surface is sampled and held for part or the entirety of the output of a photoelectric converter, this held output is nonlinearized to be compared with a preceding held and nonlinearized output of part or the entirety of the output of the photoelectric converter, the compared value is sampled and held, and extreme values of the displacement of the focus of an image rendered to the photoelectric elements from this held output are derived.
Inventors
- 👤 Toshitatsu Suzuki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 11:37
CPC Classifications
G; G02; G02B; G02B7/00; G02B7/28; G02B7/36
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
157 words
A focusing detection device characterized in that it comprises a group of photoelectric elements which share a small light receiveing area in an imaging surface or in a surface optically equivalent thereto and which are disposed adjacent to one another; an electrically driving device for sequentially obtaining an output from one of the terminals of the photoelectric element group; a circuit for sampling and holding an output from said one terminal; a device for obtaining the difference between the output of the photoelectric element group and the output of the photoelectric element before the sampling and holding is effected; a circuit for nonlinearizing the output of the device for obtaining the difference; a device for summing the output of this circuit over part or the entirety of the photoelectric element; and a device for obtaining extreme values within the range of the displacement of an optical image rendered to the photoelectric elements corresponding to the summed value.
Claim 2
Dependent Claim
157 words
A focusing detection device characterized in that it comprises a group of photoelectric elements which share a small light receiveing area in an imaging surface or in a surface optically equivalent thereto and which are disposed adjacent to one another; an electrically driving device for sequentially obtaining an output from one of the terminals of the photoelectric element group; a circuit for sampling and holding an output from said one terminal; a device for obtaining the difference between the output of the photoelectric element group and the output of the photoelectric element before the sampling and holding is effected; a circuit for nonlinearizing the output of the device for obtaining the difference; a device for summing the output of this circuit over part or the entirety of the photoelectric element; and a device for obtaining extreme values within the range of the displacement of an optical image rendered to the photoelectric elements corresponding to the summed value.
Claim 3
Dependent Claim
75 words
A focusing detection device as claimed in claim 1 further characterized in that the summed output derived by the device for summing the output after the nonlinearizing processing over part of the entirety of the photoelectric elements is divided by the nonlinearized output of the sum of the outputs of the photoelectric elements before the sampling and holding, and thereafter, the extreme values within the range of the displacement of the optical image are obtained.
Claim 4
Dependent Claim
34 words
A focusing detection device as claimed in claim 1 or 2 further characterized in that the output of the photoelectric output is analog-to-digital converted before summing and then is added by a digit signal.
References Cited (Backward Citations)
US3945037A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-04-26 | 1985-10-26 | 1986-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-04-26 | 1989-10-26 | 1990-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-04-26 | 1993-10-26 | 1994-04-27 | $7700.00 | Window Closed / Lapsed |