Patent EP0425309A2 successfully refreshed from Google Patents.
EP0425309A2
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EP
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Electronically pulsed laser system
Assignee: Coherent Inc
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Filing: 1990-10-26
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Granted: —
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Expires: 2010-10-26
Abstract
Abstract For a laser (2) capable of continuous wave operation, a power supply (4) for supplying pulsed power to the laser includes circuitry (76, 78) for modulating the power supplied to the laser in order to generate a pulsed laser output beam. The pulsed operating mode reduces the amount of heat generated during system operation, so that the system may be cooled by an internal. self-contained coolant flow loop. An independent safety monitoring system (46, 54) is capable of terminating tbe laser output in response to any unsafe failure of the control system. An argon laser tube (2) capable of generating between 6 and 7 kilowatts of heat at full continuous wave power generates only 2.5 kilowatts of average power during the electronically pulsed operating mode. A power supply control board (76) controlled by microprocessor based control electronics (6) and the safety monitor (54) controls a tube pulse starter (82) and a power MOSFET pass bank (78) connected in series with the laser tube (2).
Inventors
- 👤 Robert J. Rorden
- 👤 Peter Keenan
- 👤 Hank Thedick
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 22:18
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/102; H01S3/02; H01S3/04; H01S3/13; H01S3/131
Claims Analysis
Total Claims: 51
Claim 1
Independent Claim
45 words
A pulsed laser system, including: a laser; a power supply for supplying pulsed power to the laser, and including electronic switching means for generating pulses of power in response to control signals; and a control means for supplying said control pulses to the power supply.
Claim 2
Dependent Claim
45 words
A pulsed laser system, including: a laser; a power supply for supplying pulsed power to the laser, and including electronic switching means for generating pulses of power in response to control signals; and a control means for supplying said control pulses to the power supply.
Claim 3
Dependent Claim
94 words
The system of claim 1, wherein the laser produces an output beam, and wherein the power supply is a DC power supply including: converter means for receiving AC power and converting the AC power into high voltage DC power; a laser starter circuit connected to the converter means, and including means for starting the laser in response to the high voltage DC power and a start control signal; and laser current means for adjusting the laser output beam in response to a light control signal, wherein the light control signal determines an exposure period.
Claim 4
Dependent Claim
15 words
The system of claim 2, wherein the AC power is single phase, 208-230 VAC power.
Claim 5
Dependent Claim
58 words
The system of claim 2, wherein the converter means includes: a semiconductor controlled rectifier unit for receiving the AC power and generating rectified power therefrom in response to firing control signals; and a capacitor storage bank connected to the semiconductor controlled rectifier unit, wherein the capacitor storage bank converts the rectified power into filtered high voltage DC power.
Claim 6
Dependent Claim
45 words
The system of claim 4, wherein the converter means includes a firing control circuit and a pair of semiconductor controlled rectifier circuits, wherein the firing control circuit generates the firing control signals, and wherein the firing control signals alternately fire the semiconductor controlled rectifier circuits.
Claim 7
Dependent Claim
36 words
The system of claim 2, wherein the laser current means includes: a MOSFET passbank for causing a selected laser current to flow through the laser for said exposure period in response to the light control signal.
Claim 8
Dependent Claim
43 words
The system of claim 2, also including a safety monitor connected to the DC power supply, and wherein the DC power supply includes a crowbar circuit for shunting laser current around the laser in response to a shutdown signal from the safety monitor.
Claim 9
Dependent Claim
53 words
The system of claim 7 wherein the laser current means includes a MOSFET passbank for causing a selected laser current to flow through the laser during the exposure period in response to the light control signal, and wherein the MOSFET passbank turns off in response to said shutdown signal from the safety monitor.
Claim 10
Dependent Claim
110 words
The system of claim 1, wherein the power supply is a DC power supply includes means for generating high voltage DC power from high voltage AC power, and also including: a contactor circuit connected to the DC power supply, wherein the contactor circuit is switchable in response to a trip signal, from a closed state to an open state preventing the high voltage AC power from reaching the DC power supply; and wherein the control means includes means for generating the trip signal, and supplying the trip signal to the contactor circuit to open the contactor circuit, thereby preventing the high voltage AC power from reaching the DC power supply.
Claim 11
Dependent Claim
23 words
The system of claim 1, also including: a closed coolant flow loop, for circulating coolant fluid past the laser and the power supply.
Claim 12
Dependent Claim
81 words
The system of claim 1, wherein the coolant fluid is water, and also including: a coolant temperature sensor for supplying a coolant temperature signal to the control means; and a coolant flow rate sensor for supplying a coolant flow rate signal to the control means, and wherein the control means generates a signal for deactivating the power supply in the event that at least. one of the coolant temperature signal and the coolant flow rate signal indicates an abnormal operating condition.
Claim 13
Dependent Claim
73 words
The system of claim 1, wherein the laser emits an output beam during an exposure period designated by the control means, and also including: a first photocell for generating a first output voltage; a second photocell for generating a second output voltage; and beam sampling means for diverting a first portion of the output beam to the first photo cell and a second portion of the output beam to the second photo cell.
Claim 14
Dependent Claim
31 words
The system of claim 12, wherein the beam sampling means is a wedge-shaped beamsplitter, and wherein the first portion of the output beam reflects from a front surface of the beamsplitter.
Claim 15
Dependent Claim
55 words
The system of claim 12, also including: a safety monitor for receiving the second output voltage and a request voltage indicative of an operator-requested output beam power, and generating a control signal for shutting down the power supply in the event that the second output voltage and the request voltage indicate an unsafe operating condition.
Claim 16
Dependent Claim
128 words
An electronically pulsed laser system, including: laser means including a gas laser tube; a DC power supply including converter means for receiving AC power and converting the AC power into high voltage DC power, starter means for ionizing the gas laser tube in response to the high voltage DC power and a start control signal, and laser current means for causing a selected laser current to flow through the laser tube for a duration determined by an exposure signal so as to cause the laser means to generate a laser output beam; and control means including a CPU programmed to generate the exposure signal and the start signal, and means for supplying the exposure signal to the laser current means and the start signal to the starter means.
Claim 17
Dependent Claim
128 words
An electronically pulsed laser system, including: laser means including a gas laser tube; a DC power supply including converter means for receiving AC power and converting the AC power into high voltage DC power, starter means for ionizing the gas laser tube in response to the high voltage DC power and a start control signal, and laser current means for causing a selected laser current to flow through the laser tube for a duration determined by an exposure signal so as to cause the laser means to generate a laser output beam; and control means including a CPU programmed to generate the exposure signal and the start signal, and means for supplying the exposure signal to the laser current means and the start signal to the starter means.
Claim 18
Dependent Claim
34 words
The system of claim 15, also including a display unit connected to the control means, and wherein the display unit includes means for commanding the CPU to generate the exposure signal with said duration.
Claim 19
Dependent Claim
50 words
The system of claim 15, also including a delivery system for receiving the laser output beam, wherein the delivery means is connected to the control means, and wherein the delivery means includes a footswitch actuatable by an operator to command the CPU to generate the exposure signal with said duration.
Claim 20
Dependent Claim
81 words
The system of claim 15, also including a first photocell for generating a first output voltage indicative of the output beam power, and wherein the control means includes: means for generating a current control signal specifying the selected laser current in response to both the first output voltage and a request voltage indicative of an operator-requested output beam power; and means for supplying the current control signal to the laser current means so as to achieve the operator-requested output beam power.
Claim 21
Dependent Claim
135 words
The system of claim 15, also including: a first photocell for generating a first output voltage indicative of the output beam power; a second photocell for generating a second output voltage indicative of the output beam power; a safety monitor for receiving the second output voltage and a request voltage indicative of an operator-requested output beam power, and generating a control signal for shutting down the DC power supply in the event that the second output Voltage and the request voltage indicate an unsafe operating condition; and wherein the control means includes means for receiving the first output voltage and generating a current control signal specifying the selected laser current in response to both the first output voltage and said request voltage, and means for supplying the current control signal to the laser current means.
Claim 22
Dependent Claim
37 words
The system of claim 19, also including: beam sampling means for diverting a first portion of the output beam to the first photo cell and a second portion of the output beam to the second photo cell.
Claim 23
Dependent Claim
31 words
The system of claim 20, wherein the beam sampling means is a wedge-shaped beamsplitter, and wherein the first portion of the output beam reflects from a front surface of the beamsplitter.
Claim 24
Dependent Claim
15 words
The system of claim 15, wherein the AC power is single phase, 208-230 VAC power.
Claim 25
Dependent Claim
58 words
The system of claim 15, wherein the converter means includes: a semiconductor controlled rectifier unit for receiving the AC power and generating rectified power therefrom in response to firing control signals; and a capacitor storage bank connected to the semiconductor controlled rectifier unit, wherein the capacitor storage bank converts the rectified power into the high voltage DC power.
Claim 26
Dependent Claim
45 words
The system of claim 23, wherein the converter means includes a firing control circuit and a pair of semiconductor controlled rectifier circuits, wherein the firing control circuit generates the firing control signals, and wherein the firing control signals alternately fire the semiconductor controlled rectifier circuits.
Claim 27
Dependent Claim
41 words
The system of claim 15, wherein the laser current means includes: a MOSFET passbank for causing the selected laser current to flow through the gas laser tube for said exposure period in response to a light control signal having said duration.
Claim 28
Dependent Claim
45 words
The system of claim 15, also including a safety monitor connected to the DC power supply, wherein the DC power supply includes: a crowbar circuit for shunting the laser current around the gas laser tube in response to a shutdown signal from the safety monitor.
Claim 29
Dependent Claim
68 words
The system of claim 26, wherein the laser current means includes a MOSFET passbank for causing the selected laser current to flow through the gas laser tube for said exposure period in response to a light control signal having said duration, wherein the shutdown signal from the safety monitor is supplied to the MOSFET passbank, and wherein the MOSFET passbank turns off in response to the shutdown signal.
Claim 30
Dependent Claim
69 words
The system of claim 15, also including: a contactor circuit connected to the DC power supply, wherein the contactor circuit is operable in response to a trip signal; and wherein the control means includes means for generating the trip signal and supplying said trip signal to the contactor circuit so as to open the contactor circuit and prevent the high voltage AC power from reaching the DC power supply.
Claim 31
Dependent Claim
26 words
The system of claim 15 also including: a closed coolant flow loop, for circulating coolant fluid past the gas laser tube and the DC power supply.
Claim 32
Dependent Claim
82 words
The system of claim 15, wherein the coolant fluid is water, and also including: a coolant temperature sensor for supplying a coolant temperature signal to the control means; and a coolant flow rate sensor for supplying a coolant flow rate signal to the control means, and wherein the control means generates a signal for deactivating the DC power supply in the event that at least one of the coolant temperature signal and the coolant flow rate signal indicates an abnormal operating condition.
Claim 33
Dependent Claim
71 words
A pulsed laser system, including: a laser capable of producing a laser output pulse when supplied with power; a power supply capable of modulating power to the laser to match the laser output pulse amplitude, shape, and duration to pre-selected parameters; and an independent monitoring system for terminating the laser output pulse upon detection of an undesirable laser output pulse parameter, such as may result from failure of the power supply.
Claim 34
Dependent Claim
71 words
A pulsed laser system, including: a laser capable of producing a laser output pulse when supplied with power; a power supply capable of modulating power to the laser to match the laser output pulse amplitude, shape, and duration to pre-selected parameters; and an independent monitoring system for terminating the laser output pulse upon detection of an undesirable laser output pulse parameter, such as may result from failure of the power supply.
Claim 35
Dependent Claim
50 words
The system of claim 31, wherein the independent monitoring system includes: a first photodetector; a second photodetector; and beam sampling means for diverting a first portion of the laser output pulse to the first photo cell and a second portion of the laser output pulse to the second photo cell.
Claim 36
Dependent Claim
31 words
The system of claim 32, wherein the beam sampling means is a wedge-shaped beamsplitter, and wherein the first portion of the output beam reflects from a front surface of the beamsplitter.
Claim 37
Dependent Claim
54 words
The system of claim 31, also including a control unit for supplying a light control signal to the power supply, and wherein the power supply includes a laser current control circuit for causing a selected laser current to flow through the laser for a selected exposure period in response to the light control signal.
Claim 38
Dependent Claim
34 words
The system of claim 34 wherein the laser current control circuit includes a MOSFET passbank, and wherein the MOSFET passbank for turns off in response to a shutdown signal from the independent monitoring system.
Claim 39
Dependent Claim
45 words
The system of claim 31, wherein the independent monitoring system includes a safety monitor for supplying a shutdown signal to the power supply, and wherein the power supply includes a crowbar circuit for shunting laser current around the laser in response to the shutdown signal.
Claim 40
Dependent Claim
78 words
The system of claim 36, wherein the independent monitoring system also includes: a first photodetector for supplying a beam monitoring signal to the safety monitor; a second photodetector; and beam sampling means for diverting a first portion of the laser output pulse to the first photodetector and a second portion of the laser output pulse to the second photodetector, wherein the safety monitor generates said shutdown signal in response to the beam monitoring signal from the first photodetector.
Claim 41
Dependent Claim
19 words
The system of claim 31, also including: a closed coolant flow loop, for circulating coolant fluid past the laser.
Claim 42
Dependent Claim
95 words
The system of claim 38, also including: a coolant temperature sensor for producing a coolant temperature signal indicative of the temperature of the coolant fluid; a coolant flow rate sensor for producing a coolant flow rate signal indicative of the flow rate of the coolant fluid; and a control unit for receiving the coolant temperature signal and the coolant flow rate signal and generating a signal for deactivating the power supply in the event that at least one of the coolant temperature signal and the coolant flow rate signal indicates an abnormal system operating condition.
Claim 43
Dependent Claim
16 words
The system of claim 31, wherein the independent monitoring system is connected to the power supply.
Claim 44
Dependent Claim
63 words
The system of claim 1, wherein the laser includes means for producing an output beam, and also including: means for monitoring the output beam to generate an output beam status signal; and means for supplying the output beam status signal to the control means, wherein the control means includes means for generating the control pulses in response to the output beam status signal.
Claim 45
Dependent Claim
60 words
The system of claim 1, wherein the laser includes means for producing a pulsed output beam in response to the pulses of power, wherein the pulsed output beam includes a pulse, wherein the pulse has a rise time of not more than about one half millisecond, and wherein the pulse has a fall time much shorter than one half millisecond.
Claim 46
Dependent Claim
55 words
The system of claim 1, wherein the laser is capable of producing a first quantity of heat when operated in a full continuous wave power mode, and wherein the laser produces an average output power less than half the first quantity of heat when operating in response to the pulsed power from the power supply.
Claim 47
Dependent Claim
45 words
The system of claim 43, wherein the first quantity of heat is in a range between 6 and 7 kilowatts, and the average output power produced by the laser when operating in response to the pulsed power from the power supply is about 2.5 kilowatts.
Claim 48
Dependent Claim
115 words
An electronically pulsed laser system, including: a laser means including a gas laser tube; a power supply; starter means for ionizing gas within the laser tube in response to a voltage signal from the power supply and a start control signal; laser current means for causing a selected laser current to flow through the laser tube for a duration determined by an exposure signal so as to cause the laser means to generate a laser output beam; and control means including a CPU programmed to generate the exposure signal and the start control signal, and means for supplying the exposure signal to the laser current means and the start control signal to the starter means.
Claim 49
Dependent Claim
115 words
An electronically pulsed laser system, including: a laser means including a gas laser tube; a power supply; starter means for ionizing gas within the laser tube in response to a voltage signal from the power supply and a start control signal; laser current means for causing a selected laser current to flow through the laser tube for a duration determined by an exposure signal so as to cause the laser means to generate a laser output beam; and control means including a CPU programmed to generate the exposure signal and the start control signal, and means for supplying the exposure signal to the laser current means and the start control signal to the starter means.
Claim 50
Dependent Claim
62 words
The system of claim 45, also including: means for monitoring the laser output beam to generate an output beam status signal; and means for supplying the output beam status signal to the control means, wherein the control means includes means for generating at least one of the exposure signal and the start control signal in response to the output beam status signal.
Claim 51
Dependent Claim
42 words
The system of claim 45, wherein the laser output beam includes a pulse, wherein the pulse has a rise time of not more than about one half millisecond, and wherein the pulse has a fall time much shorter than one half millisecond.
References Cited (Backward Citations)
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