US5236876A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Body of cerium-doped quartz glass
Assignee: US Philips Corp
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Filing: 1991-07-24
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Granted: 1993-08-17
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Expires: 2011-07-24
Abstract
Abstract A body of cerium-doped quartz glass is manufactured by melting together silicon oxide and a cerium (III) silicate compound, preferably Ce 2 Si 2 O 7 , in a reducing atmosphere. The invention provides a method of manufacturing said cerium-silicate compound having a tetragonal crystal structure. The quartz glass manufactured can be suitably used in a lamp envelope of UV-absorbing quartz glass, the water content in the quartz glass being less than 1 ppm.
Inventors
- 👤 Henricus A. M. Van Hal
- 👤 Renatus Aerts
- 👤 Emmanuel Papanikolau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:41
CPC Classifications
C; C03; C03C; C03C1/00; C01; C01B; C01B33/00; C01B33/20; C03C3/00; C03C3/04; C03C3/06; C03C2201/00; C03C2201/06; C03C2201/30; C03C2201/34; C03C2201/3423; C03C2203/00; C03C2203/10; Y; Y10; Y10S; Y10S65/00; Y10S65/01; Y10S65/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
54 words
A method of manufacturing a body of cerium-doped quartz glass having a water content of less than 1 ppm by heating together a mixture of silicon dioxide and a cerium (III) silicate compound in a reducing atmosphere at a temperature exceeding 1100° C. and for a time at least sufficient to melt said mixture.
Claim 2
Independent Claim
54 words
A method of manufacturing a body of cerium-doped quartz glass having a water content of less than 1 ppm by heating together a mixture of silicon dioxide and a cerium (III) silicate compound in a reducing atmosphere at a temperature exceeding 1100° C. and for a time at least sufficient to melt said mixture.
Claim 3
Dependent Claim
26 words
A method as claimed in claim 1, characterized in that the cerium III silicate compound used has the composition Ce 2 Si 2 O 7 .
Claim 4
Dependent Claim
80 words
A method of claim 2 wherein the cerium (III) silicate Ce 2 Si 2 O 7 is manufactured by spray drying a mixture of a silicon dioxide sol and a cerium salt decomposable to cerium dioxide, heating the powder formed in the presence of oxygen at a temperature sufficient to decompose the cerium salt into cerium dioxide and then heating the resultant mixture of a cerium dioxide and silicon dioxide in a reducing atmosphere at a temperature exceeding 1100° C.
Claim 5
Dependent Claim
101 words
A method of claim 2 wherein the cerium (III) silicate Ce 2 Si 2 O 7 is manufactured by adding an excess of an aqueous sol of ammonium hydroxide to a mixture of a silicon dioxide sol and a cerium salt decomposable to cerium dioxide thereby forming a precipitate of silicon dioxide and cerium hydroxide, filtering off the precipitate of silicon dioxide and cerium hydroxide, and heating the precipitate in oxygen at a temperature at least sufficient to decompose the cerium hydroxide to cerium dioxide and then heating the resultant mixture in a reducing atmosphere at a temperature exceeding 1100° C.
Claim 6
Dependent Claim
83 words
A method of claim 2 wherein the cerium (III) silicate compound is manufactured by heating a mixture of a silicon dioxide sol and a cerium salt decomposable to cerium dioxide to convert said mixture to a gel, drying said gel, grinding said gel to form a powder, and heating said powder in the presence of oxygen at a temperature sufficient to decompose said cerium salt to cerium dioxide and then heating said powder in a reducing atmosphere at a temperature exceeding 1100° C.
Claim 7
Dependent Claim
40 words
The method of claim 3 in which the mixture is heated in the reducing atmosphere at a temperature below 1300° C. and the cerium silicate produced has the composition Ce 2 Si 2 O 7 and a tetragonal crystal structure.
Claim 8
Dependent Claim
40 words
The method of claim 4 in which the mixture is heated in the reducing atmosphere at a temperature below 1300° C. and the cerium silicate produced has the composition Ce 2 Si 2 O 7 and a tetragonal crystal structure.
Claim 9
Dependent Claim
40 words
The method of claim 5, in which the mixture is heated in the reducing atmosphere at a temperature below 1300° C. and the cerium silicate produced has the composition Ce 2 Si 2 O 7 and a tetragonal crystal structure.
Claim 10
Dependent Claim
16 words
Cerium silicate having the composition Ce 2 Si 2 O 7 and a tetragonal crystal structure.
Claim 11
Dependent Claim
16 words
Cerium silicate having the composition Ce 2 Si 2 O 7 and a tetragonal crystal structure.
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) | 1996-08-16 | 1997-02-15 | 1997-08-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-08-16 | 2001-02-15 | 2001-08-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-08-16 | 2005-02-15 | 2005-08-17 | $7700.00 | Window Closed / Lapsed |