Back to results
US 4,306,813 AGranted
Apparatus for determining faults in strip material
AssigneeErwin Sick GmbH Optik-Elektronik
InventorErwin Sick
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeErwin Sick GmbH Optik-Elektronik
InventorErwin Sick
Estimating the term…
Apparatus for determining faults in strip material is disclosed in this application which enables both color defects and distortions of the surface of the strip material to be recognized. It its general form the apparatus illuminates the material surface at a specific angle with white light and an optical system directs the light leaving the surface to a number of photodetection devices which detect the various angles at which light leaves the surface. The deviations of these angles from the direction of specular reflection, or unimpeded transmission, are characteristic of the nature of the distortion of the surface of the strip material. At least the photodetection device which receives the specularly reflected or normally transmitted light and preferably all the photodetection devices, includes two photodetectors, which detect light in different spectral ranges by means of associated beam splitting and filtering devices. In this way color defects such as stains or spots on the surface can also be recognized.
Apparatus for determining faults on strip material with a light deflecting device illuminated by an incident light beam to form a scanning light bead on the strip, a cylindrical lens extending over the scanning region and having a focal line extending along the scanning track of the scanning light bead on the strip, a strip-like cylindrical mirror arranged behind the cylindrical lens and spaced therefrom with its focal line extending optically at right angles to the direction of scanning movement of the scanning light bead, and a light receiving device with at least two photodetectors arranged in the focal plane of the cylindrical mirror the said photodetectors to receive light from light beams which leave the strip in different angular ranges with a first one of the photodetectors arranged to receive light leaving the strip at the angle of reflection and wherein by means of filtering, only light in a first spectral range is transmitted to the first photodetector and at least a portion of the beam transmitted to the first photodetector is branched off prior to filtering and, after the filtering out of a second spectral range, is passed to a further photodetector.
Apparatus for determining faults on strip material with a light deflecting device illuminated by a light beam to form a scanning light bead on the strip, a cylindrical lens extending over the scanning region and having a focal line extending the scanning track of the scanning light bead on the strip, a strip-like cylindrical mirror arranged behind and spaced from therefrom with its focal line extending optically at right angles to the direction of scanning movement of the scanning light bead and a light detecting device arranged in the focal plane of the cylindrical mirror for receiving light therefrom and having at least two light conducting rods arranged alongside one another parallel to the scanning direction and each having a stepped mirror arrangement on a strip-like surface zone thereof, there being photodetectors provided at end faces of the light conducting rods with one of said light conducting rods being arranged to receive light leaving the strip at the angle of reflection, and wherein the one light conducting rod which is covered at its central region where the light would impinge with an exactly specularly reflecting surface, if necessary taking into account the unavoidable trivial tilting that can occur during transport of the strip, is covered by a stop which is impervious to light.
Dependencies are inferred from the claim text.