Patent US3899751A successfully refreshed from Google Patents.
US3899751A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Long life molecular gas laser
Assignee: Individual
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Filing: 1973-12-03
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Granted: 1975-08-12
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Expires: 1993-12-03
Abstract
Abstract A cold cathode molecular gas laser in which the molecular dissociation at the cathode surface leading to gas depletion through formation of scaling layers and successive sputtering is counteracted by the choice of a cathode material whose scaling layers can be reduced in an atmosphere that is still compatible with laser action is described. Furthermore, among the cathode materials so selected the ones that form or are doped to form semiconducting scaling layers can support higher cathode current densities at lower sputtering rates than the ones that form insulating layers of scale. The selection of cathode materials from the first groups of the periodic table leads to a minimum of negative ions in the sputtering products. Deposits stay therefore confined near the cathode and do no harm to laser windows and mirrors. As an example, sealed off CO2 lasers that have lifetimes in excess of 10,000 hours with cold cathodes selected according to these principles have been constructed.
Inventors
- 👤 Urs E Hochuli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:41
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/038; H01S3/0388; H01S3/0382
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
106 words
In a CO2 gas laser having means forming an elongated gas filled bore, an anode and a cold cathode for laser excitation of the gas in said bore, the improvements for extending the life of said gas laser comprising a reducing gas mixture compatible with laser action in combination with a cold cathode material whose discharge created scale can be reduced over a substantially short time interval by said gas mixture to minimize layers of scale matter on the cold cathode and in the sputtering products thus maintaining the partial pressures of the gas mixture components over a period of time of at least 10,000 hours.
Claim 2
Dependent Claim
106 words
In a CO2 gas laser having means forming an elongated gas filled bore, an anode and a cold cathode for laser excitation of the gas in said bore, the improvements for extending the life of said gas laser comprising a reducing gas mixture compatible with laser action in combination with a cold cathode material whose discharge created scale can be reduced over a substantially short time interval by said gas mixture to minimize layers of scale matter on the cold cathode and in the sputtering products thus maintaining the partial pressures of the gas mixture components over a period of time of at least 10,000 hours.
Claim 3
Dependent Claim
18 words
The laser defined in claim 1 wherein the cathode material is selected to achieve semiconducting layers of scale.
Claim 4
Dependent Claim
26 words
The laser defined in claim 1 wherein the cathode material is selected to be one that forms a minimum of negative ions in its sputtering products.
Claim 5
Dependent Claim
41 words
The laser defined in claim 1 wherein said cathode includes copper and elements selected from the group I and group II of the periodic table and said bore is filled with a reducing gas mixture comprising He, CO2, CO, and Xe.
Claim 6
Dependent Claim
41 words
The laser defined in claim 1 wherein the cathode includes silver and elements selected from group I and group II of the periodic table and said laser bore is filled with a reducing gas mixture comprising He, CO2, CO, and Xe.
Claim 7
Dependent Claim
28 words
The laser defined in claim 5 wherein said cathode consists of an internally oxidized silver - copper alloy with 70 percent to 97 percent silver content (by weight).
Claim 8
Dependent Claim
55 words
The invention defined in claim 1 wherein said cathode includes platinum-copper alloys varying from about 70 percent Pt-30 percent Cu to about 50 percent Pt - 50 percent CU (by weight) and said reducing gas mixture is selected from the group comprising He, CO2, N2, H2, and Xe and He, CO2, N2, H2O, and Xe.
Claim 9
Dependent Claim
106 words
In a gas laser having means forming an elongated bore and laser end pieces at the ends of said bore, a laser gas mixture in said bore, and an anode and a cold cathode for inducing laser action in said laser gas mixture, said laser gas mixture being selected from the groups comprising He, CO2, N2 and He, CO2, CO, the improvement comprising a cathode material selected from an element of groups I and II of the periodic table and reducible in the laser gas mixture to maintain the composition ratios of said gas mixture stable over a period of time of at least 10,000 hours.
Claim 10
Dependent Claim
106 words
In a gas laser having means forming an elongated bore and laser end pieces at the ends of said bore, a laser gas mixture in said bore, and an anode and a cold cathode for inducing laser action in said laser gas mixture, said laser gas mixture being selected from the groups comprising He, CO2, N2 and He, CO2, CO, the improvement comprising a cathode material selected from an element of groups I and II of the periodic table and reducible in the laser gas mixture to maintain the composition ratios of said gas mixture stable over a period of time of at least 10,000 hours.
Claim 11
Dependent Claim
12 words
The laser defined in claim 8 wherein said cathode material includes copper.
Claim 12
Dependent Claim
22 words
The laser defined in claim 9 wherein said cathode material includes silver alloyed with said copper wherein said copper is internally oxidized.
Claim 13
Dependent Claim
16 words
The laser defined in claim 9 wherein said gas mixture is He, CO2, CO, and Xe.
Claim 14
Dependent Claim
16 words
The laser defined in claim 10 wherein said gas mixture is He, CO2, CO and Xe.
Claim 15
Dependent Claim
124 words
In a gas laser having means forming an elongated bore and laser end pieces at the ends Of said bore, a laser gas mixture in said bore, and an anode and a cold cathode for inducing laser action in said laser gas mixture, said laser gas mixture being selected from the groups comprising He, CO2, N2and He, CO2, CO, the improvement comprising a cathode material selected from elements in groups VII and VIII of the periodic table and reducible in the laser gas mixture to maintain the composition ratios of said gas mixture stable over a period of time of at least 10,000 hours and an electric field component transverse to said elongated bore to deflect ions from travel to the laser end pieces.
Claim 16
Dependent Claim
124 words
In a gas laser having means forming an elongated bore and laser end pieces at the ends Of said bore, a laser gas mixture in said bore, and an anode and a cold cathode for inducing laser action in said laser gas mixture, said laser gas mixture being selected from the groups comprising He, CO2, N2and He, CO2, CO, the improvement comprising a cathode material selected from elements in groups VII and VIII of the periodic table and reducible in the laser gas mixture to maintain the composition ratios of said gas mixture stable over a period of time of at least 10,000 hours and an electric field component transverse to said elongated bore to deflect ions from travel to the laser end pieces.
Claim 17
Dependent Claim
18 words
The laser defined in claim 8 including operative amounts of one or more of Xe, H2, and H2O.
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) | 1978-08-11 | 1979-02-10 | 1979-08-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-11 | 1983-02-10 | 1983-08-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-11 | 1987-02-10 | 1987-08-12 | $7700.00 | Window Closed / Lapsed |