Patent US4949005A successfully refreshed from Google Patents.
US4949005A
Expired / Lapsed
US
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Tantala-silica interference filters and lamps using same
Assignee: General Electric Co
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Filing: 1988-11-14
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Granted: 1990-08-14
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Expires: 2008-11-14
Abstract
Abstract Thin film interference filters consisting of alternating layers of tantala and silica suitable for high temperature use on electric lamps have been made by heat treating at 550°-675° C. before using the filters at high temperature. Tungsten halogen lamps made with such heat treated filters have been thermally cycled for thousands of cycles at 900° C. with no film loss and with satisfactory optical performance.
Inventors
- 👤 Thomas G. Parham
- 👤 Seshu Desu
- 👤 Charles D. Tschetter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 02:15
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/20; G02B5/28; G02B5/281; G02B5/282; C; C03; C03C; C03C17/00; C03C17/34; C03C17/3411; C03C17/3417; H; H01; H01J; H01J61/00; H01J61/02; H01J61/30; H01J61/35; H01K; H01K1/00; H01K1/28; H01K1/32
Claims Analysis
Total Claims: 43
Claim 1
Independent Claim
66 words
An interference filter thin film optical coating produced by a low pressure chemical vapor deposition process and consisting essentially of alternating layers of tantala and silica having a total of at least 12 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm.
Claim 2
Dependent Claim
66 words
An interference filter thin film optical coating produced by a low pressure chemical vapor deposition process and consisting essentially of alternating layers of tantala and silica having a total of at least 12 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm.
Claim 3
Dependent Claim
18 words
The filter of claim 1 wherein said silica has an SiO 2 content of at least about 95%.
Claim 4
Dependent Claim
16 words
The filter of claim 2 wherein the total number of layers is at least about 16.
Claim 5
Dependent Claim
16 words
The filter of claim 3 wherein the total number of layers is at least about 20.
Claim 6
Dependent Claim
16 words
The filter of claim 4 wherein the total number of layers is at least about 24.
Claim 7
Dependent Claim
19 words
The filter of claim 5 exhibiting less than about 4% diffuse reflection at a wavelength between about 1500-2000 nm.
Claim 8
Dependent Claim
84 words
As a composition of matter, a quartz substrate supporting an interference filter thin film optical coating produce by a low pressure chemical vapor deposition process and exhibiting good adhesion to said quartz substrate, said filter consisting essentially of alternating layers of tantala and silica having a total of at least 12 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm.
Claim 9
Dependent Claim
84 words
As a composition of matter, a quartz substrate supporting an interference filter thin film optical coating produce by a low pressure chemical vapor deposition process and exhibiting good adhesion to said quartz substrate, said filter consisting essentially of alternating layers of tantala and silica having a total of at least 12 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm.
Claim 10
Dependent Claim
18 words
The composition of claim 7 wherein said silica has an SiO 2 content of at least about 95%.
Claim 11
Dependent Claim
16 words
The composition of claim 8 wherein the total number of layers is at least about 16.
Claim 12
Dependent Claim
16 words
The composition of claim 9 wherein the total number of layers is at least about 20.
Claim 13
Dependent Claim
16 words
The composition of claim 10 wherein the total number of layers is at least about 24.
Claim 14
Dependent Claim
19 words
The composition of claim 11 exhibiting less than about 4% diffuse reflection at a wavelength between about 1500-2000 nm.
Claim 15
Dependent Claim
46 words
The composition of claim 9 wherein less than 5% of said coating is removed from said substrate as measured by a Scotch tape adhesion test after said composition has been heated to a temperature of at least about 800° C. for at least about one hour.
Claim 16
Dependent Claim
46 words
The composition of claim 12 wherein less than 5% of said coating is removed from said substrate as measured by a Scotch tape adhesion test after said composition has been heated to a temperature of at least about 800° C. for at least about one hour.
Claim 17
Dependent Claim
46 words
The product of claim 13 wherein less than 5% of said coating is removed from said substrate as measured by a Scotch tape adhesion test after said composition has been heated to a temperature of at least about 800° C. for at least about one hour.
Claim 18
Dependent Claim
16 words
The product of claim 15 wherein said silica is at least about 95% SiO 2 .
Claim 19
Dependent Claim
90 words
An electric lamp comprising a light transmissive vitreous envelope enclosing an electric light source and an interference filter produced by a low pressure chemical vapor deposition process provided on the surface of said envelope and exhibiting good adhesion thereto, said filter consisting essentially of alternating layers of tantala and silica having a total of at least 16 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm.
Claim 20
Dependent Claim
90 words
An electric lamp comprising a light transmissive vitreous envelope enclosing an electric light source and an interference filter produced by a low pressure chemical vapor deposition process provided on the surface of said envelope and exhibiting good adhesion thereto, said filter consisting essentially of alternating layers of tantala and silica having a total of at least 16 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm.
Claim 21
Dependent Claim
18 words
The lamp of claim 17 wherein said silica has an SiO 2 content of at least about 95%.
Claim 22
Dependent Claim
16 words
The lamp of claim 18 wherein the total number of layers is at least about 20.
Claim 23
Dependent Claim
19 words
The lamp of claim 19 exhibiting less than about 4% diffuse reflection at a wavelength between about 1500-2000 nm.
Claim 24
Dependent Claim
15 words
The lamp of claim 20 wherein said light source is a filament or electric arc.
Claim 25
Dependent Claim
11 words
The lamp of claim 21 wherein said envelope is hermetically sealed.
Claim 26
Dependent Claim
10 words
The lamp of claim 22 wherein said envelope is quartz.
Claim 27
Dependent Claim
47 words
The lamp of claim 17 wherein less than 5% of said filter is removed from said lamp envelope as measured by a Scotch tape adhesion test after said composition has been heated to a temperature of at least about 800° C. for at least about one hour.
Claim 28
Dependent Claim
47 words
The lamp of claim 21 wherein less than 5% of said filter is removed from said lamp envelope as measured by a Scotch tape adhesion test after said composition has been heated to a temperature of at least about 800° C. for at least about one hour.
Claim 29
Dependent Claim
47 words
The lamp of claim 23 wherein less than 5% of said filter is removed from said lamp envelope as measured by a Scotch tape adhesion test after said composition has been heated to a temperature of at least about 800° C. for at least about one hour.
Claim 30
Dependent Claim
86 words
A process for making a tantala/silica interference film on a vitreous substrate useful at temperatures in excess of about 600° C. which comprises depositing alternating layers of tantala and silica on said substrate by a low pressure chemical vapor deposition process for a total of at least 16 layers to form a coated substrate, followed by heating the coated substrate at a temperature of from about 550°-675° C. for about 0.5-5 hours before exposing said coated substrate to said elevated temperature in excess of 675° C.
Claim 31
Dependent Claim
86 words
A process for making a tantala/silica interference film on a vitreous substrate useful at temperatures in excess of about 600° C. which comprises depositing alternating layers of tantala and silica on said substrate by a low pressure chemical vapor deposition process for a total of at least 16 layers to form a coated substrate, followed by heating the coated substrate at a temperature of from about 550°-675° C. for about 0.5-5 hours before exposing said coated substrate to said elevated temperature in excess of 675° C.
Claim 32
Dependent Claim
44 words
The process of claim 27 wherein, after being heated to 550°-675° C. for 1-5 hours, said coated substrate is further heated to a temperature about as high as that temperature to which said film will be exposed for a period of about 0.1-5 hours.
Claim 33
Dependent Claim
15 words
The process of claim 27 wherein said filter consists of at least 20 total layers.
Claim 34
Dependent Claim
10 words
The process of claim 29 wherein said substrate comprises quartz.
Claim 35
Dependent Claim
25 words
The process of claim 30 wherein said film on said substrate exhibits less than about 4% diffuse reflection at a wavelength between about 1500-2000 nm.
Claim 36
Dependent Claim
20 words
The process of claim 31 wherein said silica contains at least about 95 wt. % S i O 2 .
Claim 37
Dependent Claim
39 words
The process of claim 32 wherein, after being heated at said 550°-675° C., is further heated to a temperature about as high as the temperature at which said film will be used for a period of about 0.1-5 hours.
Claim 38
Dependent Claim
28 words
The process of claim 27 wherein said coated substrate is heated at a temperature of from about 600°-675° C. before exposing said coated substrate to said elevated temperature.
Claim 39
Dependent Claim
28 words
The process of claim 28 wherein said coated substrate is heated at a temperature of from about 600°-675° C. before exposing said coated substrate to said elevated temperature.
Claim 40
Dependent Claim
28 words
The process of claim 32 wherein said coated substrate is heated at a temperature of from about 600°-675° C. before exposing said coated substrate to said elevated temperature.
Claim 41
Dependent Claim
122 words
As a product-by-process, an interference filter thin film optical coating on a vitreous substrate and exhibiting good adhesion thereto wherein said film consists essentially of alternating layers of tantala and silica having a total of at least 16 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm, said film formed by depositing alternating layers of silica and tantala on said substrate by a chemical vapor deposition process to form a coated substrate, followed by heating the coated substrate to a temperature of about 550°-675° C. and holding same within said 550°-675° C. temperature range for about 1-5 hours.
Claim 42
Dependent Claim
122 words
As a product-by-process, an interference filter thin film optical coating on a vitreous substrate and exhibiting good adhesion thereto wherein said film consists essentially of alternating layers of tantala and silica having a total of at least 16 layers and exhibiting (i) a randomized crack pattern when viewed at 50 times optical magnification and (ii) diffuse reflection of no greater than about 5% at a wavelength of from about 1500-2000 nm, said film formed by depositing alternating layers of silica and tantala on said substrate by a chemical vapor deposition process to form a coated substrate, followed by heating the coated substrate to a temperature of about 550°-675° C. and holding same within said 550°-675° C. temperature range for about 1-5 hours.
Claim 43
Dependent Claim
46 words
The produce of claim 37 wherein less than 5% of said coating is removed from said substrate as measured by a Scotch tape adhesion test after said composition has been heated to a temperature of at least about 800° C. for at least about one hour.
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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) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |