Patent ID: 8232503
Filing Date: 2012-07-31
Classification: B23K

Abstract:
1. A processing system for thermally processing a workpiece, comprising: a source of laser radiation emitting at a laser wavelength; a beam splitting reflective surface, said source of laser radiation being positioned on a first side of said reflective surface; projection optics disposed between said first side of said reflective surface and said workpiece, at least one of said reflective surface and said projection optics comprising material having a fluorescence wavelength band lying above said laser wavelength; a pyrometer positioned on a second side of said reflective surface opposite first side, said pyrometer being sensitive to a pyrometer wavelength in a band lying between (a) the laser radiation wavelength and (b) the fluorescence wavelength band, wherein said projection optics images a region of said substrate being thermally processed onto said pyrometer; and a razor-edge filter between said pyrometer and said reflective surface, said razor-edge filter having a cut-off wavelength edge transition, said filter tuned to block wavelengths lying below said edge transition and to pass wavelengths above said edge transition, said edge transition being less than 10 nm wide, said edge transition being above said laser wavelength and below said pyrometer wavelength; a pyrometer filter having a passband lying below said fluorescence wavelength.