Patent US3236578A successfully refreshed from Google Patents.
US3236578A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Visual concentration observation system
Assignee: Individual
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Filing: 1960-05-13
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Granted: 1966-02-22
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Expires: 1980-05-13
Abstract
No abstract record available.
Inventors
- 👤 Mackworth Norman Humphrey
- 👤 Thomas Edward Roland Llewellyn
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:25
CPC Classifications
A; A61; A61B; A61B3/00; A61B3/10; A61B3/113
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
140 words
APPARATUS FOR DETERMINING THE POINT OF VISUAL CONCENTRATION OF A SUBJECT, COMPRISING A CAMERA, A LENS FOR RECEIVING AND FOCUSING LIGHT FROM A SCENE, A BEAM-SPLITTING UNIT INTERPOSED BETWEEN SAID CAMERA AND LENS, A TELESCOPING VERTICAL TUBE, A LIGHT SOURCE AND A REFLECTOR MOUNTED AT THE LOWER END OF THE TUBE, A PENTAPRISM MOUNTED AT THE UPPER END OF THE TUBE, A TRIANGULAR PRISM NEXT TO THE PENETAPRISM AND SAID BEAM-SPLITTING UNIT TO TRANSMIT LIGHT THEREBETWEEN WHICH HAS BEEN TRANSMITTED FROM SAID LIGHT SOURCE BY THE CORNEA OF AN EYE INTO SAID REFLECTOR AND UP SAID TUBE TO SAID PENTAPRISM, A SURFACE ON WHICH A PART OF SAID TRANSMITTED LIGHT AND AN IMAGE FOCUSED BY THE FIRST-MENTIONED LENS ARE RECEIVED THROUGH SAID BEAMSPLITTING UNIT, AND A ROOF PRISM, TRIANGULAR PRISM AND VIEWING LENS FOR TRANSMITTING SAID IMAGE TO AN OBSERVER.
Claim 2
Dependent Claim
140 words
APPARATUS FOR DETERMINING THE POINT OF VISUAL CONCENTRATION OF A SUBJECT, COMPRISING A CAMERA, A LENS FOR RECEIVING AND FOCUSING LIGHT FROM A SCENE, A BEAM-SPLITTING UNIT INTERPOSED BETWEEN SAID CAMERA AND LENS, A TELESCOPING VERTICAL TUBE, A LIGHT SOURCE AND A REFLECTOR MOUNTED AT THE LOWER END OF THE TUBE, A PENTAPRISM MOUNTED AT THE UPPER END OF THE TUBE, A TRIANGULAR PRISM NEXT TO THE PENETAPRISM AND SAID BEAM-SPLITTING UNIT TO TRANSMIT LIGHT THEREBETWEEN WHICH HAS BEEN TRANSMITTED FROM SAID LIGHT SOURCE BY THE CORNEA OF AN EYE INTO SAID REFLECTOR AND UP SAID TUBE TO SAID PENTAPRISM, A SURFACE ON WHICH A PART OF SAID TRANSMITTED LIGHT AND AN IMAGE FOCUSED BY THE FIRST-MENTIONED LENS ARE RECEIVED THROUGH SAID BEAMSPLITTING UNIT, AND A ROOF PRISM, TRIANGULAR PRISM AND VIEWING LENS FOR TRANSMITTING SAID IMAGE TO AN OBSERVER.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1969-02-21 | 1969-08-23 | 1970-02-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1973-02-21 | 1973-08-23 | 1974-02-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1977-02-21 | 1977-08-23 | 1978-02-22 | $7700.00 | Window Closed / Lapsed |