Patent US3579018A successfully refreshed from Google Patents.
US3579018A
Expired / Lapsed
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Luminescent materials
Assignee: British Lighting Industries Ltd
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Filing: 1969-04-18
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Granted: 1971-05-18
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Expires: 1989-04-18
Abstract
Abstract New phosphors, emitting a red fluorescence and suitable for use in high-pressure mercury vapor lamps, consist of zinc aluminate activated by chromium in which some of the alumina is replaced by boron oxide.
Inventors
- 👤 Peter Whitten Ranby
- 👤 David Richard Palowkar
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 10:01
CPC Classifications
C; C09; C09K; C09K11/00; C09K11/08; C09K11/67; C09K11/68; C09K11/687; C09K11/685; H; H01; H01J; H01J61/00; H01J61/02; H01J61/38; H01J61/42; H01J61/44
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
18 words
A composition according to claim 1 wherein between 0.05 and 0.3 mole of A12O3 is replaced by B2O3.
Claim 2
Independent Claim
87 words
A method of preparing a phosphor comprising the steps of: preparing a mixture comprising compounds of zinc, aluminum, chromium an boron, said compounds being selected from oxides of said elements and compounds which decompose on heating to form such oxides and volatile byproducts, said mixture being formulated with proportions corresponding to 1.01-1.25 moles aluminum oxide and 0.002-0.04 mole chromous oxide per mole of zinc oxide, ad boron oxide in an amount replacing up to 0.4 mole aluminum oxide; and heating said mixture to form a luminescent product.
Claim 3
Dependent Claim
75 words
A high-pressure mercury vapor lamp comprising: an arc tube; electrodes in said arc tube; a fill comprising inert gas and mercury vapor in said arc tube; a light-transmitting outer envelope surrounding and spaced from said arc tube; and a coating on a surface of said envelope comprising a boron-containing chromium-activated zinc aluminate phosphor having the molecular composition: 1 ZnO: 1.01-1.25 A12O3: 0.002-0.04 Cr2O3 in which up to 0.4 mole of A12O3 is replaced by B2O3.
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |