US3605596A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera provided with a depth-of-field controller
Assignee: Canon Inc
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Filing: 1969-11-04
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Granted: 1971-09-20
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Expires: 1989-11-04
Abstract
Abstract A ZOOM LENS HAS A VARYING DEPT OF FIELD FOR EACH FOCAL LENGTH. VALUS ARE SET CORRESPONDING TO THE NEAR POINT AND THE FAR POINT OF A DESIRED OBJECT SPACE. THESE VALUES ARE SET AS RESISTANCES ON EITHER SIDE OF A BRIDGE CIRCUIT CONNECTED ON ONE SIDE OF THE BRIDGE CIRCUIT IS A RESISTANCE VALUE CORRESPONDING TO THE INSTANT DEPT OF FIELD SETTING WHICH IS A COMBINATION OF A FOCAL LENGTH AND F-STOP. NORMALLY THE BRIDGE CIRCUIT IS UNBALANCED IN ONE DIRECTION BUT WHEN THE ACTUAL DEPTH OF FIELD BECOMES SMALLER THAN THE DESIRED SETTING, THE BRIDGE CIRCUIT BECOMES BALANCED IN THE OPPOSITE DIRECTION THEREBY SENDING A CIRCUIT RESPONSE WHICH CAN BE UTILIZD BY THE OPERATOR OR THE CAMERA.
Inventors
- 👤 Karl Vockenhuber
- 👤 Otto Freudenschuss
- 👤 Eduard Keznickl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 01:45
CPC Classifications
G; G03; G03B; G03B17/00; G03B17/02
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-09-19 | 1975-03-21 | 1975-09-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-19 | 1979-03-21 | 1979-09-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-19 | 1983-03-21 | 1983-09-20 | $7700.00 | Window Closed / Lapsed |