US3676043A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photoflash lamp having laminated glass envelope
Assignee: GTE Sylvania Inc
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Filing: 1970-10-26
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Granted: 1972-07-11
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Expires: 1990-10-26
Abstract
Abstract A LAMINATED GLASS ENVELOPE OF A PHOTOFLASH LAMP COMPRISES THREE SEPARATE LAYERS OF GLASS FUSED TO ONE ANOTHER TO PROVIDE AN INTEGRAL ENVELOPE. THE CENTER LAYER OF GLASS HAS A HIGHER COEFFICIENT OF THERMAL EXPANSION THAN THE INNER AND OUTER LAYERS WITH THE RESULT THAT THE CENTER LAYER IS IN TENSION AND THE OTHER LAYERS ARE UNDER COMPRESSIVE STRESS. THE ENVELOPE AS A RESULT IS STRONGER THAN CONVENTIONAL SINGLE LAYER GLASS ENVELOPES AND MORE RESISTANT TO INTERNAL PRESSURE WHEN THE LAMP IS FLASHED.
Inventors
- 👤 John Wallace Anderson
- 👤 Frederick Ardel Loughridge
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 23:55
CPC Classifications
F; F21; F21K; F21K5/00; F21K5/02; F21K5/023; F21K5/026
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) | 1975-07-11 | 1976-01-10 | 1976-07-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-07-11 | 1980-01-10 | 1980-07-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-07-11 | 1984-01-10 | 1984-07-11 | $7700.00 | Window Closed / Lapsed |