Patent ID: 7638731

Claim:
A system for laser machining a target specimen having a surface, comprising: a laser source and objective lens cooperating to produce a machining laser beam that has an image column and propagates along a machining beam axis for incidence on the target specimen, the objective lens and the target specimen being separated by an axial distance; a beam positioning system operable to change the axial distance and to move the machining laser beam and target specimen relative to each other in a direction along a machining beam path to process the target specimen at selected locations; a tracking device positioned in non-contacting relationship with the surface of the target specimen and in operative association with the machining laser beam to lead the machining laser beam during the relative movement in the direction along the machining beam path, the tracking device operable to repeatedly measure in real time a distance between the surface of the target specimen and the objective lens during the relative movement and produce a signal corresponding to the distance measured; and a laser controller cooperating with the beam positioning system and responding to the signal to set the axial distance separating the objective lens and the target specimen during the relative movement to control the position of the image column relative to the target specimen at the selected locations, and to deliver controlled amounts of energy of the machining laser beam for incidence on the target specimen at the selected locations in correspondence to the axial distance set.