US3683295A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gas laser discharge tube
Assignee: RCA Corp
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Filing: 1970-05-08
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Granted: 1972-08-08
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Expires: 1990-05-08
Abstract
Abstract In a gas laser discharge tube, such as a He-Cd laser discharge tube, where the active lasing gas is cataphoretically transported from the anode region toward the cathode region during the occurrence of a discharge, a diffusion return path is provided between the cathode region and the anode region. The return path has conductive means located therein to prevent a discharge within the return path, but still permit the diffusion of gas therethrough. In the case where the cataphoretically transported gas is a metal vapor, a density control heater may be placed in the vicinity of the cathode to maintain the density of metal vapor molecules in the cathode vicinity at that value which results in a minimum amount of unwanted noise being generated.
Inventors
- 👤 Karl Gerhard Hernqvist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:36
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/031
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
320 words
In a metal-vapor laser discharge tube responsive to a given operating voltage applied thereto for producing a discharge therein, said tube comprising a gas-filled envelope having spaced anode and cathode electrodes situated therein, wherein said gas includes as a portion thereof a given metal vapor which is cataphoretically transported from said anode to said cathode electrodes in response to a discharge in said tube; the improvement therewith of: first means for dividing the interior of said tube between said anode and cathode electrodes into a first region of a first given length and a second region of a second given length which communicate with each other at a plurality of predetermined longitudinally - spaced points including respective first and second points in the vicinity of said respective electrodes, each of said first and second lengths being sufficiently short to permit per se respective discharges to take place in both said respective first and second regions in response to the application of said operating voltage to said anode and cathode electrodes, and second means for preventing any discharge in said second region including therein a plurality of longitudinally-distributed, separate, spaced, conductive grid elements, each of said grid elements dividing an entire cross section of said second region iNto a plurality of gas-diffusing openings separated from each other by conductive material, the maximum size of any of said openings being sufficiently small to prevent a discharge from passing therethrough, and the spacing between any pair of adjacent grid elements being such that the potential difference existing therebetween in response to said operating voltage being applied to said anode and cathode electrodes is below the cold-cathode breakdown voltage between that pair of adjacent grid elements, whereby in response to said operating voltage being applied to said anode and cathode electrodes a discharge takes place only in said first region and said second region acts as a return path for said cataphoretically-transported metal vapor.
Claim 2
Dependent Claim
320 words
In a metal-vapor laser discharge tube responsive to a given operating voltage applied thereto for producing a discharge therein, said tube comprising a gas-filled envelope having spaced anode and cathode electrodes situated therein, wherein said gas includes as a portion thereof a given metal vapor which is cataphoretically transported from said anode to said cathode electrodes in response to a discharge in said tube; the improvement therewith of: first means for dividing the interior of said tube between said anode and cathode electrodes into a first region of a first given length and a second region of a second given length which communicate with each other at a plurality of predetermined longitudinally - spaced points including respective first and second points in the vicinity of said respective electrodes, each of said first and second lengths being sufficiently short to permit per se respective discharges to take place in both said respective first and second regions in response to the application of said operating voltage to said anode and cathode electrodes, and second means for preventing any discharge in said second region including therein a plurality of longitudinally-distributed, separate, spaced, conductive grid elements, each of said grid elements dividing an entire cross section of said second region iNto a plurality of gas-diffusing openings separated from each other by conductive material, the maximum size of any of said openings being sufficiently small to prevent a discharge from passing therethrough, and the spacing between any pair of adjacent grid elements being such that the potential difference existing therebetween in response to said operating voltage being applied to said anode and cathode electrodes is below the cold-cathode breakdown voltage between that pair of adjacent grid elements, whereby in response to said operating voltage being applied to said anode and cathode electrodes a discharge takes place only in said first region and said second region acts as a return path for said cataphoretically-transported metal vapor.
Claim 3
Dependent Claim
72 words
The tube defined in claim 1, wherein the cross-sectional area of said second region is sufficiently greater than the cross-sectional area of said first region to permit the rate of diffusion of molecules of gas therethrough back from said cathode to said anode electrodes to be at all times substantially equal to the rate at which molecules of gas are cataphoretically transported through said first region between said anode and cathode electrodes.
Claim 4
Dependent Claim
31 words
The tube defined in claim 2, wherein, the cross-sectional area of said second region is in the order of one hundred times greater than the cross-sectional area of said first region.
Claim 5
Dependent Claim
44 words
The gas discharge tube defined in claim 1, wherein said gas is a mixture of helium and cadmium vapor, ions of said cadmium vapor occurring in response to a discharge being the active lasing material, said portion of said gas comprising said cadmium vapor.
Claim 6
Dependent Claim
183 words
The tube defined in claim 1, wherein said second means comprises a predetermined number of said grid elements longitudinally spaced from each other along the length of said second region, each of said elements having a significant length dimension and being configured to divide the entire volume defined by the cross-section of said second region and the length of said element into a bundle of separate gas conduits, each conduit of which extends from one end to the other end of that element, the cross-sectional area of any single gas conduit of said bundle being sufficiently smaller than either the cross-section of said second region or the length of that conduit to prevent a discharge from taking place therethrough and the spacing between said respective elements and said elements and said electrodes being close enough to prevent a discharge from taking place therebetween, the predetermined number being larger than Va/Vc, where Va is the normally applied discharge voltage at which the tube operates and Vc is the normal cold cathode drop which depends on the grid element material and gas in said tube.
Claim 7
Dependent Claim
151 words
The tube defined in claim 1, wherein said second means comprises a predetermined number of said grid elements longitudinally spaced from each other along the length of said second region, each of said elements having a significant length dimension, each of said elements comprising a longitudinal conductive cylinder having a conductive mesh tight enough to prevent a discharge from taking place covering at least one end of each cylinder, the cross-section of each cylinder providing a single conduit just smaller than the cross-section of said second region and the spacing between said respective elements and said elements and said electrodes being close enough to prevent a discharge from taking place therebetween, the predetermined number being larger than Va/Vc, where Va is the normally applied discharge voltage at which the tube operates and Vc is the normal cold cathode drop which depends on the grid element material and gas in said tube.
Claim 8
Dependent Claim
54 words
The tube defined in claim 1, wherein said first region comprises a first portion of said envelope which is disposed about a first longitudinal axis and said second region comprises a second portion oF said envelope disposed about a second longitudinal axis oriented in spaced substantially parallel relationship with respect to said first axis.
Claim 9
Dependent Claim
217 words
The tube defined in claim 7, wherein said envelope further includes a third portion in the vicinity of said anode electrode which communicates with the one end of both said first and second portions of said envelope, said third portion of said envelope including an evaporator section located between said one end of said first portion and one end of said second portion and an evaporator heater in cooperative relationship therewith which heats said evaporator section for vaporizing a metal contained therein to maintain a desired density of metal vapor in said evaporator section, said vapor being cataphoretically transported from said evaporator section toward said cathode electrode through said first portion of said envelope, a fourth portion of said envelope in the vicinity of said cathode electrode which communicates with the other end of both said first and second portions of said envelope, said fourth portion including a given section thereof located between said other end of said first portion and said other end of said second portion and a density control heater in cooperative relationship therewith which heats said given section to a temperature which maintains a given density of metal vapor in said given section at which the noise level of the laser light output is substantially less than when said given section is unheated.
Claim 10
Dependent Claim
30 words
The tube defined in claim 8, wherein said temperature and given density are such as to reduce the noise level of the laser light output to less than five percent.
Claim 11
Dependent Claim
18 words
The tube defined in claim 9, wherein said metal vapor is cadmium and said temperature is about 235*.
Claim 12
Dependent Claim
169 words
The tube defined in claim 1, comprising an envelope disposed about a given longitudinal axis which extends from one end of the tube to the other end of the tube, a first anode electrode disposed toward one end of the tube, a second anode electrode disposed toward the other end of the tube, a cathode electrode disposed intermediate said first and second anode electrodes, a bore member defining a bore therethrough which is longitudinally disposed about said given axis, said bore member being disposed within said envelope in spaced relationship therewith, said bore member extending from the vicinity of said first anode to the vicinity of said second anode, said bore member having a hole therein in the vicinity of said cathode electrode to thereby permit said bore to communicate with the space of said envelope exterior to said bore member in the vicinity of said cathode electrode, whereby said bore defines said first region and the spacing between said bore member and said envelope defines said second region.
Claim 13
Dependent Claim
182 words
In a gas laser tube comprising a gas-filled envelope having spaced anode and cathode electrodes situated therein, wherein said gas includes at least a portion thereof which is a metal vapor that is cataphoretically transported from said anode toward said cathode electrodes in response to a discharge in said tube, the improvement therewith comprising an evaporator section of said envelope located between said electrodes in the vicinity of said anode electrode and an evaporator heater in cooperative relationship therewith which heats said evaporator section for vaporizing a metal contained therein to maintain a desired density of metal vapor in said evaporator section, said vapor being cataphoretically transported from said evaporator section toward said cathode electrode, and a given section of said envelope located between said electrodes in the vicinity of said cathode electrode and a density control heater in cooperative relationship therewith which heats said given section to a temperature which maintains a given density of metal vapor in said given section at which the noise level of the laser light output is substantially less than when said given section is unheated.
Claim 14
Dependent Claim
182 words
In a gas laser tube comprising a gas-filled envelope having spaced anode and cathode electrodes situated therein, wherein said gas includes at least a portion thereof which is a metal vapor that is cataphoretically transported from said anode toward said cathode electrodes in response to a discharge in said tube, the improvement therewith comprising an evaporator section of said envelope located between said electrodes in the vicinity of said anode electrode and an evaporator heater in cooperative relationship therewith which heats said evaporator section for vaporizing a metal contained therein to maintain a desired density of metal vapor in said evaporator section, said vapor being cataphoretically transported from said evaporator section toward said cathode electrode, and a given section of said envelope located between said electrodes in the vicinity of said cathode electrode and a density control heater in cooperative relationship therewith which heats said given section to a temperature which maintains a given density of metal vapor in said given section at which the noise level of the laser light output is substantially less than when said given section is unheated.
Claim 15
Dependent Claim
30 words
The tube defined in claim 12, wherein said temperature and given density are such as to reduce the noise level of the laser light output to less than five percent.
Claim 16
Dependent Claim
19 words
The tube defined in claim 13, wherein said metal vapor is cadmium and said temperature is about 235* C.
References Cited (Backward Citations)
US3531734A
Cited
US3464028A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-08 | 1976-02-07 | 1976-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-08 | 1980-02-07 | 1980-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-08 | 1984-02-07 | 1984-08-08 | $7700.00 | Window Closed / Lapsed |