Coherent light generators – Particular component circuitry – For driving or controlling laser
Reexamination Certificate
1999-12-21
2001-12-04
Arroyo, Teresa M. (Department: 2881)
Coherent light generators
Particular component circuitry
For driving or controlling laser
C372S025000, C372S034000, C372S038070, C372S038100
Reexamination Certificate
active
06327286
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to pulse power sources, particularly to an apparatus and method for controlling the pulse propagation delay and jitter in a magnetic modulator circuit, more particularly pertaining to excimer lasers and other gas discharge lasers.
BACKGROUND
The use of magnetic pulse compression circuits (magnetic modulators) to create high voltage, high current, short duration electrical pulses has been well described (see for example W. S. Melville, “The use of Saturable Reactors as Discharge Devices for Pulse Generators,”
Radio Section,
Paper No. 1034, pp. 185-207, Sep. 15, 1950). Particularly, magnetic modulators have been applied advantageously to drive pulsed gas discharges for excimer lasers and other pulsed gas discharge lasers (see for example Ball et al. U.S. Pat. No. 5,177,754, Jan. 5, 1993.
Pulse propagation delay in a magnetic modulator depends upon the characteristic volt-second product(s) required to saturate the core(s) of the individual magnetic switch element(s). Since the volt-second product is nearly invariant for any individual core, operation at different voltage levels typically results in different pulse propagation or throughput delays relative to a trigger signal from master trigger (a shorter delay at higher voltages and a longer delay at lower voltages). However, in some applications, it is important to maintain a constant propagation delay, regardless of variable operating voltage levels, such that measurement events can be timed relative to a trigger signal from the master trigger. Jitter or variation in timing of the output pulse relative to th e trigger signal from the master trigger can also be important in these applications. Additionally, temperature fluctuations can lead to variations in propagation delay and/or jitter in timing of pulses.
Although circuit have been used previously to control pulse propagation delay and jitter in magnetic modulators, they have typically been complex, inflexible, and/or relatively crude and inaccurate in the compensation that they allow (see for example Hill et al. AReliable High Repetition Rate Thyratron Grid Driver Used with a Magnetic Modulator,@ 8th IEEE International Pulsed Power Conference, San Diego, Calif., 1991, IEEE Catalog #91CH3052-8).
A voltage timing compensation circuit in the prior art (see for example Cymer ELS5600 Data DOC. ID: ICLACY00.EPS) compensates for the delay variation at different voltages by adding a low level delay to a trigger signal from a master trigger when the magnetic modulator operates at higher voltages.
The prior art voltage timing compensation circuit operates by sampling the voltage of the initial operating stage of a magnetic modulator just prior to master trigger initiation. The sampled voltage is then digitized and used to drive a digital delay generator, which adds to the low level trigger signal a timing delay proportional to the sampled voltage. Thus according to the prior art cited above, delay compensation is linear relative to operating voltage, whereas the actual dependence of pulse propagation delay on voltage is non-linear.
Because the characteristic volt-second product of the magnetic switch element(s) is temperature dependent, some prior art implementations comprise a temperature timing compensation circuit to correct for variations in delay caused by fluctuations in operating temperature relative to a nominal design ambient temperature.
In accordance with certain prior art embodiments, this temperature timing compensation circuit comprises RC components that synthesize the approximate thermal characteristics of the system.
What is needed in the art is a simple, reliable circuit for timing compensation of a magnetic modulator that more accurately compensates for effects of voltage and/or temperature than does the prior art. Further needed in the art is a circuit for pulse timing control of a magnetic modulator in response to other independent variables, that is simple, accurate, and reliable.
SUMMARY
The present invention relates generally to pulse power sources, particularly to an apparatus and method for controlling the pulse propagation delay and jitter in a magnetic modulator circuit, more particularly pertaining to excimer lasers and other gas discharge lasers.
In some embodiments of the invention, improvement over prior art voltage timing compensation circuits is achieved by incorporating a function generator to provide a more accurate non-linear compensation to pulse timing delay, which is typically a non-linear function instead of a linear function of voltage.
In other embodiments of the invention, improvement over prior art temperature timing compensation circuits is achieved by providing for actual temperature, measurements to be made and used to drive the timing compensation circuitry for a more accurate temperature timing compensation than provided by the prior art temperature synthesis, while still using a relatively simple compensating circuit.
In further embodiments a very fast timing compensation circuit combines both voltage and temperature timing compensation without analog to digital conversion.
REFERENCES:
patent: 4549091 (1985-10-01), Fahlen et al.
patent: 5138622 (1992-08-01), Friede et al.
patent: 5142166 (1992-08-01), Birx
patent: 5177754 (1993-01-01), Ball et al.
patent: 5309462 (1994-05-01), Taylor et al.
patent: 5313481 (1994-05-01), Cook et al.
patent: 5319665 (1994-06-01), Birx
patent: 5359279 (1994-10-01), Gidon et al.
patent: 5514918 (1996-05-01), Inatomi et al.
patent: 6016325 (2000-01-01), Ness et al.
J.V. Hill, et al., “Reliable, High Repetition Rate Thyratron Grid Driver Used with a Magnetic Modulator”, 8th IEEE International Pulsed Power Conference, San Diego, CA, 1991, IEEE Catalog # 91CH3052-8.
W.S. Melville, “The use of Saturable Reactors as Discharge Devices for Pulse Generators,”Radio Section, Paper No. 1034, pp. 185-207, Sep. 15, 1950.
Birx, et. al, “Basic Principles Governing the Design of Magnetic Switches,”Lawrence Livermore Laboratory Publication UCID-18831, Nov. 18, 1980.
E.M. Lassiter, P.R. Johannessen, R.H. Spencer, “High-Power Pulse Generation Using Semiconductors and Magnetic Cores,” AIEE Summer General Meeting, pp. 511-517, Nov. 1960.
H. Yanagise, et. al., “Solid-State Power Device for Excimer Laser,”Proceedings of the Joint Conference on Electronic Devices and Semiconductor Power Conversion, Sep. 13, 1995.
Cymer ELS5600 Data, DOC. ID: ICLCACY00.EPS.
Yatsui, “Industrial application of pulse power and particle beams,” Laser and Particle Beams (1989), vol. 7, part 4, pp. 733-741, Printed in Northern Ireland.
Johns David M.
Ness Richard M.
Partlo William N.
Sandstrom Richard L.
Arroyo Teresa M.
Cymer Inc.
Menefee James
Ross, Esq. John R.
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