AOM modulation techniques employing plurality of tilt-angled transducers to improve laser system performance
AssigneeElectro Scientific Industries, Inc.
InventorJay Johnson
Life of this patent
Estimating the term…
Abstract
Digital control of frequency and/or amplitude modulation techniques of an intracavity and/or extracavity AOM (60) facilitate substantially full extinction of a laser beam (90) to prevent unwanted laser energy from impinging a workpiece (80); facilitate laser pulse amplitude stability through closed-loop control of pulse-to-pulse laser energy; facilitate beam-positioning control including, but not limited to, closed-loop control for applications such as alignment error correction, beam walk rectification, or tertiary positioning; and facilitate employment of more than one transducer on an AOM (60) to perform any of the above-listed applications.
Claims51
A method for enhancing performance of an AOM suited for positioning along a beam path between a laser and a workpiece, the AOM having a beam entrance surface, a beam exit surface, and a first transducer that is positioned on a first transducer surface of the AOM, the first transducer surface being in a first plane that is transverse to the beam entrance surface, comprising:
- generating a laser beam along a beam path that impinges a workpiece;
- propagating the laser beam through the AOM positioned along the beam path;
- controlling application of a first frequency of a first RF signal applied to the first transducer that modulates within a first transducer modulation zone that traverses the beam path to affect a first deflection angle of the beam path along a first workpiece axis with respect to a surface of the workpiece;
- controlling application of a second frequency of a second RF signal applied to a second transducer positioned on a second transducer surface of the AOM, the second transducer surface being in a second plane that is transverse to the beam entrance surface, and the second transducer modulating within a second transducer modulation zone that traverses the beam path to affect a second deflection angle of the beam path along the first workpiece axis, the second transducer being spaced-apart and oriented at a small angle with respect to the first transducer such that the first and second transducer modulation zones are nonparallel;
- and
- coordinating the application of the first and/or second RF signals to deflect the laser beam to impinge the workpiece at a desired beam position resulting from application of one or both of the first or second frequencies to provide a deflection propagation direction resulting from the application of the first and/or second RF signals.
A method for enhancing performance of an AOM suited for positioning along a beam path between a laser and a workpiece, the AOM having a beam entrance surface, a beam exit surface, and a first transducer that is positioned on a first transducer surface of the AOM, the first transducer surface being in a first plane that is transverse to the beam entrance surface, comprising:
- generating a laser beam along a beam path that impinges a workpiece;
- propagating the laser beam through the AOM positioned along the beam path;
- controlling a first frequency of a first RF signal applied to the first transducer that modulates within a first transducer modulation zone that traverses the beam path to affect a first deflection angle of the beam path along a first workpiece axis with respect to a surface of the workpiece;
- controlling a second frequency of a second RF signal applied to a second transducer positioned on a second transducer surface of the AOM, the second transducer surface being in a second plane that is transverse to the beam entrance surface, and the second transducer modulating within a second transducer modulation zone that traverses the beam path to affect a second deflection angle of the beam path along the first workpiece axis, the second transducer being spaced-apart and oriented at a small angle with respect to the first transducer such that the first and second transducer modulation zones are nonparallel;
- and
- coordinating the frequencies of the first and second RF signals to deflect the laser beam to impinge the workpiece at a desired beam position resulting from a cooperative deflection angle resulting from the first and second deflection angles imparted by the first and second RF signals.
Dependencies are inferred from the claim text.