Machining head for a laser machining apparatus

摘要

A machining head of a laser machining apparatus comprises focusing optics which focus laser radiation. A measuring device measures changes of the focal length of the optics. The measuring device has a light source for generating measuring light different from the laser radiation. A light-exit window for the measuring light is imaged, with assistance of the focusing optics or a part thereof, onto a reflecting reference surface arranged to be stationary relative to the exit window and the focusing optics. A light sensor detects measuring light that has emerged from the exit window, has passed through the focusing optics or the part thereof, was reflected on the reflecting surface, and has again passed through the focusing optics or the part thereof. An evaluating device ascertains the change in the focal length of the focusing optics from measuring signals made provided by the light sensor.

主权项

1. A machining head for a laser machining apparatus that is configured to machining of workpieces with laser radiation, said machining head comprising:
focusing optics configured to focus laser radiation guided to the machining head in a focal spot, a measuring device configured to measure changes in the focal length of the focusing optics, wherein the measuring device comprises
a light source configured to generate measuring light that is different from the laser radiation,a light-exit window from which the measuring light emerges during operation of the measuring device, the light-exit window being imaged, with the assistance of the focusing optics or a part thereof, onto a reflecting surface which is arranged to be stationary relative to the light-exit window and the focusing optics and is not part of the focusing optics,a light sensor which is configured to register measuring light that has emerged from the light-exit window, has passed through the focusing optics or the part thereof, was reflected on the reflecting surface, and has again passed through the focusing optics or the part thereof, wherein the measuring light impinges at least partly onto regions of optical surfaces of the focusing optics onto which the laser radiation also impinges,an evaluating device which is configured to ascertain a change in the focal length of the focusing optics from measuring signals provided by the light sensor.