US3695879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hologram life extension
Assignee: International Business Machines Corp
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Filing: 1970-04-20
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Granted: 1972-10-03
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Expires: 1990-04-20
Abstract
Abstract LASER-INTERROGATED HOLOGRAMS PRODUCED IN SILVER HALIDE EMULSIONS BY AN ETCH-BLEACH DEVELOPMENT PROCESS HAVE DESIRABLE PROPERTIES OF LIGHT DIFFRACTION EFFICIENCY BUT ARE SUBJECT TO RAPID LOSS OF DIFFRACTION EFFECTIVENESS OVER PERIODS OF EXPOSURE TO HIGH ENERGY DENSITY LEVELS OF INTERROGATION LGHT. IT HAS BEEN FOUND THAT POST-DEVELOPMENT HARDENING, ESPECIALLY BY SUCCESSIVE APPLICATION OF A HARDENING SOLUTION AND HEAT CAN PROLONG EFFECTIVENESS HALFLIFE BY A CONSIDERABLE FACTOR. THE HEATING STEP IS MOST EFFECTIVE WHEN CARRIED OUT IN VACUUM OR INERT GASEOUS ATMOSPHERE.
Inventors
- 👤 Frank P Laming
- 👤 Solomon L Levine
- 👤 Glenn T Sincerbox
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:53
CPC Classifications
G; G03; G03C; G03C5/00; G03C5/26; G03C11/00; G03C11/06; Y; Y10; Y10S; Y10S359/00; Y10S359/90; Y10S430/00; Y10S430/146
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |