The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 10, 2002
Filed:
Apr. 12, 2002
Hans-Stephan Albrecht, Goettingen, DE;
Klaus Wolfgang Vogler, Goettingen, DE;
Thomas Schroeder, Goettingen, DE;
Lambda Physik AG, Goettingen, DE;
Abstract
A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge chamber. The driving voltage is determined to be in one of multiple driving voltage ranges that are adjusted based on the aging of the system. Within each range, gas injections and gas replacements are preferably performed based on total applied electrical energy to the discharge and/or alternatively, on time and/or pulse count.