Patent ID: 7875830

Claim:
A laser processing machine head monitoring system comprising: a light-transmissive focusing optical element having two broad surfaces for transmission of a processing laser beam defining a beam axis, and a peripheral surface featuring a delineated planar, angled, profiled, or shaped surface segment; an optical element holder comprising a clamping body and defining a cavity in which the optical element is retained against rotation by interaction between the clamping body and the delineated surface segment; a light source mounted to the holder and arranged to couple a beam of light into the optical element through the peripheral surface at a first location, through the optical element, and toward the peripheral surface at a second location; a light receiver arranged to receive light from the light source that passes through the optical element and is internally reflected from the second location on the peripheral surface of the optical element; and a controller configured to monitor an intensity of light received from the light receiver to monitor a status of the optical element, wherein a change in intensity is used to determine a change in performance of the optical element; and wherein the delineated surface segment comprises the first location or the second location of the peripheral surface or both.