Abstract: An apparatus for breakthrough detection in laser workpiece processing operations performed by a pulsed laser. The breakthrough detection apparatus comprises a video camera that receives and senses returned radiated light energy from a target area on the workpiece each time the pulsed laser beam strikes the target area and vaporizes some of the material of the workpiece. The camera output signal from the video camera is fed to a breakthrough detection processor that compares the level of the camera output signal, which is proportional to the intensity of the returned radiated light energy received by the video camera, to a predetermined threshold. A breakthrough detection signal is generated by the breakthrough detection processor when the level of the camera output signal falls below the predetermined threshold due to the fact that workpiece breakthrough has occurred and little if any material remains to be vaporized by the pulsed laser beams.

Abstract: Method and apparatus for maintaining the focal point of a laser beam used for laser machining relative to a workpiece, including an optical distance measuring sensor having a measurement beam, a mirror for combining the measurement and laser beams into a predetermined optical path having a common axis for both beams, and a focusing element which may be in the form of a refractive lens or a reflective parabolic mirror located in the optical path, and a control means for controlling the location of the focal point of the laser beam based on the distance sensed by measurement beam. In drilling, once the hole breaks through the workpiece, the application of the laser beam can be stopped by observing a departure from the incremental distance measurement change.

Abstract: Method and apparatus for maintaining the focal point of a laser beam used for laser machining relative to a workpiece, including an optical distance measuring sensor having a measurement beam, a mirror for combining the measurement and laser beams into a predetermined optical path having a common axis for both beams, and a focusing element which may be in the form of a refractive lens or a reflective parabolic mirror located in the optical path, and a control means for controlling the location of the focal point of the laser beam based on the distance sensed by measurement beam. In drilling, once the hole breaks through the workpiece, the application of the laser beam can be stopped by observing a departure from the incremental distance measurement change.

Abstract: A system for forming an image on the outer surface of a plastic card and for correlating image data with corresponding alphanumeric data, comprises a data acquisition subsystem, an embosser/encoder, an exposure station for scanning an electrophotographic medium in accordance with digital image data generated by the data acquisition system, and a toning station for toning the electrophotographic medium to produce a toner image. The embosser/encoder forms identifying information corresponding to the alphanumeric data on the card and provides the embossed/encoded card to an image transfer station. At the image transfer station, the toner image on the electrophotographic medium is transferred to a portion of the card through heat and pressure. A protective layer is placed over the fused toner image.