Treatment of light emitting films to extend their useful life
Abstract
Abstract The method of driving, or of preconditioning, a vacuum-deposited light-emitting film of the type which comprises a binary compound of zinc and sulphur or selenium together with a manganese activator, so as to extend the useful life of the film. The voltage of the driving alternating current is raised so as substantially to maintain the initial luminescence of the film, and preferably is continuously raised, so as to accomplish the same. Also, this treatment may initially be given to the film and then discontinued, the film''s useful life thereby having been extended beyond that life to which, without the treatment and at a constant voltage, its luminescence would have decayed to only one half of its initial value at that voltage.
Inventors
- 👤 E Soxman
Bibliographic Details
Claims Analysis
Total Claims: 4References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-02 | 1976-07-03 | 1977-01-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-02 | 1980-07-03 | 1981-01-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-02 | 1984-07-03 | 1985-01-02 | $7700.00 | Window Closed / Lapsed |