Detecting and monitoring contamination of optical component e.g. lens in apparatus for laser material processing, comprises projecting measuring beam emitted by light source at incident angle onto outer surface of optical component

摘要

The method comprises projecting a measuring beam (11) emitted by a light source at an incident angle onto an outer surface (5a) of an optical component (5), guiding a beam reflected from the outer surface of a protective glass under an angle of reflection corresponding to an angle of incidence by an aperture plate to a first light-sensitive detector (2) to detect an intensity of the reflected beam, and detecting an intensity of the diffused radiation scattered from the outer surface of the component under a scattering angle by a second light-sensitive detector. The method comprises projecting a measuring beam (11) emitted by a light source at an incident angle onto an outer surface (5a) of an optical component (5), guiding a beam reflected from the outer surface of a protective glass under an angle of reflection corresponding to an angle of incidence by an aperture plate to a first light-sensitive detector (2) to detect an intensity of the reflected beam, detecting an intensity of the diffused radiation scattered from the outer surface of the component under a scattering angle by a second light-sensitive detector, and determining a degree of contamination of the component from the detected intensity of the reflected beam and the scattered radiation. The method further comprises: detecting an intensity of a transmission beam transmitted by the optical component using a third light-sensitive detector (4);recording a performance of the measuring beam emitted by the light source via a monitor diode, where the degree of contamination of the optical component is detected from the detected intensity of the scattered radiation and the performance of the measuring beam; and readjusting the performance of the measuring beam emitted by the light source via a control device such that a signal detected by the first detector of the reflected beam independent of the degree of contamination of the optical component is kept constant. The measuring beam emitted from the light source is collimated, and strikes in a central region on the outer surface of the optical component. The detectors, with respect to the wavelength of the measuring beam, are wavelength-selective light-sensitive. A magnitude of the angle of incidence is equal to a magnitude of the angle of reflection. The angle of reflection and the scattering angle are different. An independent claim is included for an apparatus for detecting and monitoring a contamination of an optical component in an apparatus for laser material processing.