Patent US3664631A successfully refreshed from Google Patents.
US3664631A
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Cylindrical lens systems for simultaneous bimeridional measurement in a lens measuring instrument
Assignee: Individual
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Filing: 1970-02-25
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Granted: 1972-05-23
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Expires: 1990-02-25
Abstract
Abstract IN A LENS MEASURING INSTRUMENT OR OPTOMETER OF THE TYPE EMPLOYING A TARGET, SCALE, AND CONVERGING LENS FOR MEASURING THE POWER OF A LENS OR THE POWER ERROR OF AN EYE IN TWO PRINCIPAL MERIDIANS, A PAIR OF INTERPOSED CYLINDRICAL LENS SYSTEMS HAVING ORTHOGONAL AXES ARE DISCLOSED FOR SEPARATING THE TARGET INTO TWO INDIVIDUALLY MOVABLE IMAGE SEGMENTS. THE LENS SYSTEMS ARE DISPOSED SUCH THAT ONE ORTHOGONAL TARGET IMAGE SEGMENT MAY BE MOVED THROUGH THE PLANE OF THE OTHER FACILITATING SIMULTANEOUS POWER MEASUREMENT OF THE TWO MERIDIANS AND ALLOWING THE USE OF A PLURALITY OF TYPES OF TARGETS.
Inventors
- 👤 David Guyton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 06:49
CPC Classifications
G; G01; G01M; G01M11/00; G01M11/02; G01M11/0228; A; A61; A61B; A61B3/00; A61B3/02; A61B3/028; A61B3/036
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) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |