US4798768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Luminescent alumino-silicate and/or alumino-borate glass comprising lanthanum and/or gadolinium and luminescent screen provided with such a glass
Assignee: US Philips Corp
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Filing: 1987-10-07
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Granted: 1989-01-17
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Expires: 2007-10-07
Abstract
Abstract Luminescent alumino-silicate and/or alumino-borate glass comprising lanthanum and/or gadolinium and activated by Tb 3+ and/or Ce 3+ and have a composition comprising 35-85 mol % of SiO 2 and/or B 2 O 3 , 1-35 mol % of La 2 O 3 and/or Gd 2 O 3 , 5-45 mol % of Al 2 O 3 and 0.5-30 mol % of Tb 2 O 3 and/or Ce 2 O 3 . The La 2 O 3 and/or Gd 2 O 3 may be replaced up to not more than 50 mol % by Y 2 O 3 , Sc 2 O 3 , Lu 2 O 3 , ZrO 2 , P 2 O 5 and/or alkaline earth metal oxides. The glass can be used in a luminescent screen, for example, of a low-pressure mercury vapour discharge lamp.
Inventors
- 👤 Gerrit Oversluizen
- 👤 Anne-Marie A. Van Dongen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 19:05
CPC Classifications
H; H01; H01J; H01J63/00; H01J63/02; H01J63/04; C; C03; C03C; C03C3/00; C03C3/04; C03C3/076; C03C3/095; C03C3/12; C03C3/14; C03C3/15; C03C4/00; C03C4/12
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
178 words
A luminescent alumino-silicate and/or alumino-borate glass comprising lanthanum and/or gadolinium and activated by a rare earth metal, characterized in that the glass is activated by at least one of the rare earth metals Tb 3+ and Ce 3+ has a composition comprising 35-85 mol% of SiO 2 and/or B 2 O 3 , 1-35 mol% of La 2 O 3 and/or Gd 2 O 3 , 5-45 mol% of Al 2 O 3 and 0.5-30 mol% of Tb 2 O 3 and/or Ce 2 O 3 in which the La 2 O 3 and/or Gd 2 O 3 are replaceable in amounts up to than 50 mol% by one or more of the oxides Y 2 O 3 , Sc 2 O 3 , Lu 2 O 3 , ZrO 2 , P 2 O 5 and the alkaline earth metal oxides, the rare earth metal oxides being at least 99.99% pure and the other oxides being at least 99.999% pure, the luminescent glass having a quantum efficiency of at least 46% when excited by 254 nm radiation.
Claim 2
Dependent Claim
178 words
A luminescent alumino-silicate and/or alumino-borate glass comprising lanthanum and/or gadolinium and activated by a rare earth metal, characterized in that the glass is activated by at least one of the rare earth metals Tb 3+ and Ce 3+ has a composition comprising 35-85 mol% of SiO 2 and/or B 2 O 3 , 1-35 mol% of La 2 O 3 and/or Gd 2 O 3 , 5-45 mol% of Al 2 O 3 and 0.5-30 mol% of Tb 2 O 3 and/or Ce 2 O 3 in which the La 2 O 3 and/or Gd 2 O 3 are replaceable in amounts up to than 50 mol% by one or more of the oxides Y 2 O 3 , Sc 2 O 3 , Lu 2 O 3 , ZrO 2 , P 2 O 5 and the alkaline earth metal oxides, the rare earth metal oxides being at least 99.99% pure and the other oxides being at least 99.999% pure, the luminescent glass having a quantum efficiency of at least 46% when excited by 254 nm radiation.
Claim 3
Dependent Claim
54 words
A luminescent glass as claimed in claim 1, characterized in that the glass comprises 50-80 mol% of SiO 2 and/or B 2 O 3 , 1-20 mol% of La 2 O 3 , 10-30 mol% of Al 2 O 3 and 0.5-15 mol% of Tb 2 O 3 and/or Ce 2 O 3 .
Claim 4
Dependent Claim
19 words
A luminescent screen having a luminescent layer comprising a luminescent alumino-silicate and/or alumino-borate glass as claimed in claim 2.
Claim 5
Dependent Claim
19 words
A luminescent screen having a luminescent layer comprising a luminescent alumino-silicate and/or alumino-borate glass as claimed in claim 1.
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) | 1992-01-17 | 1992-07-18 | 1993-01-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-01-17 | 1996-07-18 | 1997-01-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-01-17 | 2000-07-18 | 2001-01-17 | $7700.00 | Window Closed / Lapsed |