CA1273403A - Control of large volume gaseous electric discharge system - Google Patents
Control of large volume gaseous electric discharge systemInfo
- Publication number
- CA1273403A CA1273403A CA000529788A CA529788A CA1273403A CA 1273403 A CA1273403 A CA 1273403A CA 000529788 A CA000529788 A CA 000529788A CA 529788 A CA529788 A CA 529788A CA 1273403 A CA1273403 A CA 1273403A
- Authority
- CA
- Canada
- Prior art keywords
- laser
- power supply
- voltage
- invention according
- pulse
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/30—Circuit arrangements in which the lamp is fed by pulses, e.g. flash lamp
- H05B41/34—Circuit arrangements in which the lamp is fed by pulses, e.g. flash lamp to provide a sequence of flashes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/09—Processes or apparatus for excitation, e.g. pumping
- H01S3/097—Processes or apparatus for excitation, e.g. pumping by gas discharge of a gas laser
Landscapes
- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Optics & Photonics (AREA)
- Lasers (AREA)
Abstract
ABSTRACT
A control circuit for a laser system having a first and a second power supply connected in parallel. A mode selec-tor is available to the laser operator to change the opera-tional mode of the laser system from continous to pulse mode or vice versa, and any combination of the modes. In the pulse mode, a series of short-time voltage pulses is super-imposed on a low power level laser mode using the circuit control characteristic of the thyratron tube to sharply increase the laser output power for the duration of the individual pulses.
A control circuit for a laser system having a first and a second power supply connected in parallel. A mode selec-tor is available to the laser operator to change the opera-tional mode of the laser system from continous to pulse mode or vice versa, and any combination of the modes. In the pulse mode, a series of short-time voltage pulses is super-imposed on a low power level laser mode using the circuit control characteristic of the thyratron tube to sharply increase the laser output power for the duration of the individual pulses.
Description
~l~73403 BAC~GROUND OF THE INVENTION:
(1) Field of the Invention One of the problems encountered when a laser system is designed and intended for use in an industrial environment is the compactness, size and reliability of the system. Lasing action in a system is obtained by subjecting a gas-filled vessel or channel to an electric discharge - the electrons provided by the discharge collide with active gas molecules thereby exciting them to higher energy levels, from which they descend to lower energy levels and emit excess energy in the form of photons, or light quanta. The population density of particles in the higher energy level must exceed that in the lower energy level to achieve optical gain. This population inversion is the opposite of the natural state.
A discharge, normally, has a very thin diameter because the heat transfer rates in different parts of the discharge are not uniform, and result in lower pressure and density at the inside of the plasma column, thus constricting the column.
(1) Field of the Invention One of the problems encountered when a laser system is designed and intended for use in an industrial environment is the compactness, size and reliability of the system. Lasing action in a system is obtained by subjecting a gas-filled vessel or channel to an electric discharge - the electrons provided by the discharge collide with active gas molecules thereby exciting them to higher energy levels, from which they descend to lower energy levels and emit excess energy in the form of photons, or light quanta. The population density of particles in the higher energy level must exceed that in the lower energy level to achieve optical gain. This population inversion is the opposite of the natural state.
A discharge, normally, has a very thin diameter because the heat transfer rates in different parts of the discharge are not uniform, and result in lower pressure and density at the inside of the plasma column, thus constricting the column.
(2) Description of the Prior Art Lasers are now used to sharply reduce production costs in those industrial applications requiring cutting, welding, drilling, heat treating and the like. However, according to industry publications, laser sales are only about three per-cent of the machine tool industry. The use of my invention with a laser will be most useful in such industrial applications as the rapid removal of paint, scale, rust or
3~73~03 other unwanted coatings whi must be removed from materials or vehicles such as ships.
Applicant is aware of the following prior art United States Patents 3,491,309, 3,581,146, 3,735,284, and 3,795,838, all to Hill.
The first listed patent to ~ill reveals a high power C02 pulse laser wherein the required pulse voltage is in the order of 200 KV to lMV. The invention to be later described herein provides a circuit for use with a high power C02 pulse laser and distinguishes from the above identified patent by providing a low level ioni3ation sustaining voltage to the laser electrodes and to superimpose short-time voltage pulse onto the low level ionization voltage.
In the invention to be described, the pulse voltage required to develop similar pulsed plasma current is much smaller than the above listed voltagQ range. This reduction in magnitude of voltage yields circuit parameters which can easily be used in an industrial environment. The uniformly distributed ionization provided by the co-pending patent application identified above provides a more uniform-pulsed plasma current distribution and is stable over a longer pulse period. This results in greater achievable pulsed output power with a superior optical mode quality over that which could be achieved using the first listed patent.
The second listed patent to Hill relates to a method of ballasting a gaseous dischar~e-tube system wherein a plurality of tubes are excited from a single power source.
.
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~27~
The third listed patent teaches the use of aerodynamic forces to control the spatial distribution of charge in a laser system to obtain a uniform plasma.
The fourth listed patent also shows the use of aero-dynamic forces to obtain uniform plasma in a laser system.
None of the above patents appears to teach or even suggest the invention revealed and claimed herein.
Reference is made to the following works for those relationships and definitions which are used herein.
"An investigation of Ejector Design by Analysis and Experiment"; Xeenan, Neumann, and Lustwerk-Journal of Applied Mechanics, page 299 September 1950.
"Gaseous Conductors - Theory and Engineering Applications"; James D. Cobine PH.D., Dover Publications, Inc. 1958 Edition.
"Basic Data of Plasma Physics"; Sanborn C. Brown, M.I.T.
Press 1959 Edition.
SUMMARY OF THE INVENTION
This invention encompasses a circuit to gate the operation of the laser to change its operation from continuous to intermittent, or pulse or vice versa or any combination thereof. The pulse operation is useful in an industrial environment performing duty as cleaning, paint removal, rust removal and the like.
It is accordingly a broad object of the invention to provide a control circuit for a laser.
It is another object of the invention to provide a .
. .
, ~
~ 34~33 control circuit ~or a laser which will selectively change the operation ~rom continuous mode to pulse mode or vice versa.
It is yet another object of the invention to provide a laser control circuit which will selectively connect parallel power supplies to a laser to switch from one operating mo~e to another or to combine`the operating modes.
It is yet still another object of the invention to pro-vide a laser pulse circuit which superimposes a series o~
short-time voltage pulses onto a low power level ionization producing direct current to provide high power lasers pulses.
~RIEF DESCRIPTION OF TH~ DRAWING
The single Ei~ure shows a scl-ematic circuit Eor tlle control of a laser system including a mode selector, whereby the laser operator can selectively operate the laser in the continuous mode or the pulse mode or any combination. A
second power supply is connected in parallel with a first power supply to superimpose a series of short-time pulses on a relatively low level DC laser voltage which results in a snort-time repetitive peak power laser output pulse many times greater than the normal continuous power output. The first power supply is infinitely variable so tlat pulse power may be superimposed upon continuous power.
~ 73403 DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawing wherein reference character indicates a Eirst power supply for multi-electrode laser 12, as shown schematically. A plurality of laser ano~es 14 are connected tllrough hallast resistors 16, current regulator 18, and pulse blocking diode 20 to the positive terminal 03 variable voltage power supply 10. A plurality o~ cathodes 22 are connected through ballast resistors 24 to the negative terminal of power supply. The positive terminal of auxiliary power supply 26 is connected to the negative terminal of power supply 10 and to ground. The purpose of power supply 26 i6 to insure that the cathodes 22 float negative with respect to ground to avoid backstreaming. This completes the Eirst power supply.
A second power supply is connected in parallel with the above described first power supply and comprises a pulse forming network shown generally as reference character 28 con-nected to the primary of step-up transformer 30. The pulse forming circuit comprises a plurality of parallel connected capacitors 32 and series connected inductance coils 34 con-nected between thyratron switch 36 and resonant charging system 38. The secondary of transformer 30 is connected at one end through blocking diodes 40 to the laser anodes 14 and at its other end through blocking diodes 42 to the laser cathodes 22 to complete the circuit. A laser operation mode ~elector, shown generally as referenced character 50, is con-nected mechanically or electrically to control the infinitely variable voltage first power supply 10 which is symbolically represented by the arrow appearing thereon. The selector is electrically connected through trigger transformer 60 to the grid of thyratron 36 for a purpose that will later be explaine~.
~2734~33 OP~RATION
In the operation of the circuit to cl~ange the laser from continuous phase to pulse phase, the mode selector is actuated by the laser operator to reduce the voltage output of ~irst power supply 10 to a low level sufficient to maintain ioniza-tion in the laser at ahout tl-e volta~e glow state, and a voltage pulse is applied to the grid of thyratron 36 through transformer 60. In the actual reduct;on to practice of the system, the operating characteristics o~ the thyratron tube was found u.seful to control the high energy short-time dura-tion pulse neededO
Gas-filled tubes generate their charge carriers from ionizing electron-molecule collisions which produce an electrically neutral plasma with electrons and positive ions moving in opposite directions. Conduction may be held off by a control grid in the absence o~ current flow, but once switched on, the ions form a space charge around the grid which tries to go negative so that its controlling electric ~ield is cancelled. This results in an out of control arc.
The gas filled tubes provide on-switching capability of almost unlimited currents, but must be externally turned off until recombination dissipates the plasma. Only then may the control grid hold-off function be re-established. Statistical ionizatlon processes can also be important when ~itter requirements are severe, or when trigger-to-breakdown times must be 0.5 nanosecond or less. Recent use of hydrogen and grounded-grid designs have shortened conventional thyratron ionization and deionization times, but hydrogen clean up pre-sents a problem, and heated reservoirs are needed to attempt to maintain a suitable equilibrium operating pressure over the tube's li~etime.
, ' , ,. .
~73403 r.~hen the thyratron 36 is fired by the voltage pulse to its control grid erom mode selec~or 50, the pulse forming net-work 28 having been charged from resonant charging system 38 generates a square wave output pulse which is applied to the primary of transformer 30. The secon~ary of transf~rmer 30 superimposes the short-time high voltage pulse on the be~ore-mentioned low level DC voltage existing acros~ the electrodes of laser 12 thus sharply increasing its output peak beam power. .State~ diferently, when the laser's plasma is controlled or adjusted to operate at a low power level suf-ficient to maintain ionization at the voltage glow state and wherein the ion density is high enough to support conduction, the system can be gated by superimposing a short-time voltage pulse through the thyratron tube circuit onto the low level voltage thus increasing the current and the output power many times for the duration of the pulse. The duration of the high current state is not long enough to develop instabilities in the discharge. For example, a 5 KW maximum continuous wave laser operated in this manner yields from zero to S KW average power; however, the peak power is many times greater than the above-mentioned continuous power. The pulse width, as an example, can be about 30 microseconds at 1000 pulses per second ~1000 PPS) yielding a peak power of perhaps 300 times the continuous power level.
Pulse forming network 28 having discharged itself through transformer 30, the grid of thyratron 36 now regains control and the pulse dies. A~roit design of circuit parameters per-mits a pulse reptition rate as a function of pulse forming circuit charging time and thyratron grid pulse-application rate.
Since voltage supply 10 is infinitely variable, any com-bination of operational modes is available at the selectionof the operation. Thus, pulse power can be superimpvsed upon continuous power to perform any given industrial operation.
An alternative and perhaps preferred switching means is revealed in United States Patent No. 4,4~2,383 to Hill issued April 10, 1984 and entitled "Plasma Switch".
The acoustic shock must be considered in this system because an acoustic wave enters the gas stream. The acoustic wave may be powerful enough to damage parts of the laser assembly by repeated stressles and would degrade the optical quality of the laser beam. Sound absorbing structure can easily be incorporated in the gas return flow cavityO
For examp e, an acoustic trap (not shown) can be effectively utilized.
It will be seen that I have provided a laser control circuit which greatly increases the flexibility and usefulness of a high power laser. It will be apparent to those skilled in the art that many changes may be made in the construction and arrangement of parts without necessarily departing from the scope of the invention as defined in the claims.
- - , ,-:. ,., : , ..
:. ' , ' , - ' :'.- - : , , :
.. : . .
. :
. . , ,: ' ' .. ' ' "
Applicant is aware of the following prior art United States Patents 3,491,309, 3,581,146, 3,735,284, and 3,795,838, all to Hill.
The first listed patent to ~ill reveals a high power C02 pulse laser wherein the required pulse voltage is in the order of 200 KV to lMV. The invention to be later described herein provides a circuit for use with a high power C02 pulse laser and distinguishes from the above identified patent by providing a low level ioni3ation sustaining voltage to the laser electrodes and to superimpose short-time voltage pulse onto the low level ionization voltage.
In the invention to be described, the pulse voltage required to develop similar pulsed plasma current is much smaller than the above listed voltagQ range. This reduction in magnitude of voltage yields circuit parameters which can easily be used in an industrial environment. The uniformly distributed ionization provided by the co-pending patent application identified above provides a more uniform-pulsed plasma current distribution and is stable over a longer pulse period. This results in greater achievable pulsed output power with a superior optical mode quality over that which could be achieved using the first listed patent.
The second listed patent to Hill relates to a method of ballasting a gaseous dischar~e-tube system wherein a plurality of tubes are excited from a single power source.
.
... :, .
..-., .: :~ .
~27~
The third listed patent teaches the use of aerodynamic forces to control the spatial distribution of charge in a laser system to obtain a uniform plasma.
The fourth listed patent also shows the use of aero-dynamic forces to obtain uniform plasma in a laser system.
None of the above patents appears to teach or even suggest the invention revealed and claimed herein.
Reference is made to the following works for those relationships and definitions which are used herein.
"An investigation of Ejector Design by Analysis and Experiment"; Xeenan, Neumann, and Lustwerk-Journal of Applied Mechanics, page 299 September 1950.
"Gaseous Conductors - Theory and Engineering Applications"; James D. Cobine PH.D., Dover Publications, Inc. 1958 Edition.
"Basic Data of Plasma Physics"; Sanborn C. Brown, M.I.T.
Press 1959 Edition.
SUMMARY OF THE INVENTION
This invention encompasses a circuit to gate the operation of the laser to change its operation from continuous to intermittent, or pulse or vice versa or any combination thereof. The pulse operation is useful in an industrial environment performing duty as cleaning, paint removal, rust removal and the like.
It is accordingly a broad object of the invention to provide a control circuit for a laser.
It is another object of the invention to provide a .
. .
, ~
~ 34~33 control circuit ~or a laser which will selectively change the operation ~rom continuous mode to pulse mode or vice versa.
It is yet another object of the invention to provide a laser control circuit which will selectively connect parallel power supplies to a laser to switch from one operating mo~e to another or to combine`the operating modes.
It is yet still another object of the invention to pro-vide a laser pulse circuit which superimposes a series o~
short-time voltage pulses onto a low power level ionization producing direct current to provide high power lasers pulses.
~RIEF DESCRIPTION OF TH~ DRAWING
The single Ei~ure shows a scl-ematic circuit Eor tlle control of a laser system including a mode selector, whereby the laser operator can selectively operate the laser in the continuous mode or the pulse mode or any combination. A
second power supply is connected in parallel with a first power supply to superimpose a series of short-time pulses on a relatively low level DC laser voltage which results in a snort-time repetitive peak power laser output pulse many times greater than the normal continuous power output. The first power supply is infinitely variable so tlat pulse power may be superimposed upon continuous power.
~ 73403 DETAILED DESCRIPTION OF THE INVENTION
Referring now to the drawing wherein reference character indicates a Eirst power supply for multi-electrode laser 12, as shown schematically. A plurality of laser ano~es 14 are connected tllrough hallast resistors 16, current regulator 18, and pulse blocking diode 20 to the positive terminal 03 variable voltage power supply 10. A plurality o~ cathodes 22 are connected through ballast resistors 24 to the negative terminal of power supply. The positive terminal of auxiliary power supply 26 is connected to the negative terminal of power supply 10 and to ground. The purpose of power supply 26 i6 to insure that the cathodes 22 float negative with respect to ground to avoid backstreaming. This completes the Eirst power supply.
A second power supply is connected in parallel with the above described first power supply and comprises a pulse forming network shown generally as reference character 28 con-nected to the primary of step-up transformer 30. The pulse forming circuit comprises a plurality of parallel connected capacitors 32 and series connected inductance coils 34 con-nected between thyratron switch 36 and resonant charging system 38. The secondary of transformer 30 is connected at one end through blocking diodes 40 to the laser anodes 14 and at its other end through blocking diodes 42 to the laser cathodes 22 to complete the circuit. A laser operation mode ~elector, shown generally as referenced character 50, is con-nected mechanically or electrically to control the infinitely variable voltage first power supply 10 which is symbolically represented by the arrow appearing thereon. The selector is electrically connected through trigger transformer 60 to the grid of thyratron 36 for a purpose that will later be explaine~.
~2734~33 OP~RATION
In the operation of the circuit to cl~ange the laser from continuous phase to pulse phase, the mode selector is actuated by the laser operator to reduce the voltage output of ~irst power supply 10 to a low level sufficient to maintain ioniza-tion in the laser at ahout tl-e volta~e glow state, and a voltage pulse is applied to the grid of thyratron 36 through transformer 60. In the actual reduct;on to practice of the system, the operating characteristics o~ the thyratron tube was found u.seful to control the high energy short-time dura-tion pulse neededO
Gas-filled tubes generate their charge carriers from ionizing electron-molecule collisions which produce an electrically neutral plasma with electrons and positive ions moving in opposite directions. Conduction may be held off by a control grid in the absence o~ current flow, but once switched on, the ions form a space charge around the grid which tries to go negative so that its controlling electric ~ield is cancelled. This results in an out of control arc.
The gas filled tubes provide on-switching capability of almost unlimited currents, but must be externally turned off until recombination dissipates the plasma. Only then may the control grid hold-off function be re-established. Statistical ionizatlon processes can also be important when ~itter requirements are severe, or when trigger-to-breakdown times must be 0.5 nanosecond or less. Recent use of hydrogen and grounded-grid designs have shortened conventional thyratron ionization and deionization times, but hydrogen clean up pre-sents a problem, and heated reservoirs are needed to attempt to maintain a suitable equilibrium operating pressure over the tube's li~etime.
, ' , ,. .
~73403 r.~hen the thyratron 36 is fired by the voltage pulse to its control grid erom mode selec~or 50, the pulse forming net-work 28 having been charged from resonant charging system 38 generates a square wave output pulse which is applied to the primary of transformer 30. The secon~ary of transf~rmer 30 superimposes the short-time high voltage pulse on the be~ore-mentioned low level DC voltage existing acros~ the electrodes of laser 12 thus sharply increasing its output peak beam power. .State~ diferently, when the laser's plasma is controlled or adjusted to operate at a low power level suf-ficient to maintain ionization at the voltage glow state and wherein the ion density is high enough to support conduction, the system can be gated by superimposing a short-time voltage pulse through the thyratron tube circuit onto the low level voltage thus increasing the current and the output power many times for the duration of the pulse. The duration of the high current state is not long enough to develop instabilities in the discharge. For example, a 5 KW maximum continuous wave laser operated in this manner yields from zero to S KW average power; however, the peak power is many times greater than the above-mentioned continuous power. The pulse width, as an example, can be about 30 microseconds at 1000 pulses per second ~1000 PPS) yielding a peak power of perhaps 300 times the continuous power level.
Pulse forming network 28 having discharged itself through transformer 30, the grid of thyratron 36 now regains control and the pulse dies. A~roit design of circuit parameters per-mits a pulse reptition rate as a function of pulse forming circuit charging time and thyratron grid pulse-application rate.
Since voltage supply 10 is infinitely variable, any com-bination of operational modes is available at the selectionof the operation. Thus, pulse power can be superimpvsed upon continuous power to perform any given industrial operation.
An alternative and perhaps preferred switching means is revealed in United States Patent No. 4,4~2,383 to Hill issued April 10, 1984 and entitled "Plasma Switch".
The acoustic shock must be considered in this system because an acoustic wave enters the gas stream. The acoustic wave may be powerful enough to damage parts of the laser assembly by repeated stressles and would degrade the optical quality of the laser beam. Sound absorbing structure can easily be incorporated in the gas return flow cavityO
For examp e, an acoustic trap (not shown) can be effectively utilized.
It will be seen that I have provided a laser control circuit which greatly increases the flexibility and usefulness of a high power laser. It will be apparent to those skilled in the art that many changes may be made in the construction and arrangement of parts without necessarily departing from the scope of the invention as defined in the claims.
- - , ,-:. ,., : , ..
:. ' , ' , - ' :'.- - : , , :
.. : . .
. :
. . , ,: ' ' .. ' ' "
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A circuit to control the operation of a laser having at least one pair of electrodes and to selectively convert laser operation from one operational mode to another comprising in combination:
(a) a laser first power supply circuit having means to vary the output voltage connected to the laser electrodes, (b) a laser second power supply circuit connected in parallel with said first power supply circuit and to the laser electrodes, and (c) switching means connected to said first power supply circuit and to the second power supply circuit to simultaneously reduce the first power supply output voltage to a level which barely sustains plasma ionization in the glow state and to apply a short-time high voltage pulse to the laser electrodes to sharply increase the plasma current, resulting in a short burst of output beam power.
(a) a laser first power supply circuit having means to vary the output voltage connected to the laser electrodes, (b) a laser second power supply circuit connected in parallel with said first power supply circuit and to the laser electrodes, and (c) switching means connected to said first power supply circuit and to the second power supply circuit to simultaneously reduce the first power supply output voltage to a level which barely sustains plasma ionization in the glow state and to apply a short-time high voltage pulse to the laser electrodes to sharply increase the plasma current, resulting in a short burst of output beam power.
2. The invention according to claim 1 including a plura-lity of blocking diodes connected between the said first power supply circuit and said second power supply circuit to prevent voltage feedback between the two circuits.
3. The invention according to claim 2 wherein the said laser second power supply circuit includes a pulse forming network connected to a switching means whereby actuation thereof reduces the first power supply output voltage, and yields repeated high voltage laser output pulses.
4. The invention according to claim 3 wherein the laser output pulses are superimposed on laser continuous power output.
5. The invention according to claim 4 wherein said switching means comprises a thyratron tube.
6. The invention according to claim 5 including sound absorbing means in the laser cavity to reduce the effect of high levels accoustic waves generated by the laser pulses.
7. For use with a high power gas laser, a circuit to operate the laser in the pulse mode comprising in combination:
(a) a first power supply having control means to operate the laser at a low voltage level sufficient to main-tain ionization where the ion density is sufficient to support conduction connected to the laser electrodes, (b) a second power supply connected in parallel with said first power supply through blocking diodes to superimpose a series of short-time voltage pulses onto the low level ioni-zation sustaining voltage to yield a series of laser pulses.
(a) a first power supply having control means to operate the laser at a low voltage level sufficient to main-tain ionization where the ion density is sufficient to support conduction connected to the laser electrodes, (b) a second power supply connected in parallel with said first power supply through blocking diodes to superimpose a series of short-time voltage pulses onto the low level ioni-zation sustaining voltage to yield a series of laser pulses.
8. The invention according to claim 7 wherein said second power supply includes a pulse forming network connected to a switching means whereby actuation of said switching means superimposes the series of short-time voltage pulses onto the ionization sustaining voltage.
9. The invention according to claim 8 wherein said switching means comprises a plasma switch.
10. The invention according to claim 9 wherein said switching means is a thyratron.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US83044986A | 1986-02-18 | 1986-02-18 | |
| US830,449 | 1986-02-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1273403A true CA1273403A (en) | 1990-08-28 |
Family
ID=25257029
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000529788A Expired CA1273403A (en) | 1986-02-18 | 1987-02-16 | Control of large volume gaseous electric discharge system |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS63502471A (en) |
| CA (1) | CA1273403A (en) |
| DE (1) | DE3790086T1 (en) |
| FR (1) | FR2594605B1 (en) |
| GB (1) | GB2194672B (en) |
| WO (1) | WO1987005161A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113977040B (en) * | 2021-11-16 | 2023-08-25 | 昆山华恒焊接股份有限公司 | High-frequency pulse current superposition circuit, welding circuit and welding equipment |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3532930A (en) * | 1967-12-22 | 1970-10-06 | Hughes Aircraft Co | Laser control circuit |
| US3646395A (en) * | 1970-05-15 | 1972-02-29 | American Optical Corp | High repetition rate laser optical pumping system |
| US3842365A (en) * | 1973-05-30 | 1974-10-15 | Westinghouse Electric Corp | Pulse glow generation for laser systems |
| US4648093A (en) * | 1984-09-06 | 1987-03-03 | Coherent, Inc. | Power supply for gas discharge lasers |
-
1987
- 1987-02-13 JP JP50155187A patent/JPS63502471A/en active Pending
- 1987-02-13 GB GB8722166A patent/GB2194672B/en not_active Expired
- 1987-02-13 WO PCT/US1987/000301 patent/WO1987005161A1/en active Application Filing
- 1987-02-13 DE DE19873790086 patent/DE3790086T1/de not_active Withdrawn
- 1987-02-16 CA CA000529788A patent/CA1273403A/en not_active Expired
- 1987-02-18 FR FR8702113A patent/FR2594605B1/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS63502471A (en) | 1988-09-14 |
| WO1987005161A1 (en) | 1987-08-27 |
| FR2594605A1 (en) | 1987-08-21 |
| FR2594605B1 (en) | 1989-05-26 |
| GB2194672B (en) | 1990-08-01 |
| GB2194672A (en) | 1988-03-09 |
| DE3790086T1 (en) | 1988-03-10 |
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