Method and device for calibrating an irradiation device

A device for performing a method of calibrating a CO2 laser of an apparatus for generatively manufacturing a three-dimensional object, wherein the apparatus layerwise applies a powdery or liquid building material onto a support of the apparatus or a previously applied layer, the applied layer defining a working plane, and irradiates the building material by the CO2 laser with energetic radiation at locations corresponding to the object so as to solidify the building material at these locations, the device comprising:

• an image converter plate, which is to be arranged in or in parallel to the working plane and outputs detectable light, when the CO2 laser irradiates predetermined positions of the image converter plate with energetic radiation, wherein the image converter plate can convert CO2 laser light into visible light to near-infrared light and the image converter plate consists of (i) a substrate which permits detectable light to pass through, (ii) an aperture mask in which apertures are located corresponding to the predetermined positions of the image converter plate, and (iii) an image converter material, and the aperture mask is arranged at an upper side of the image converter plate and the image converting material is arranged between the substrate and the aperture mask;
• a light detector, which detects the detectable light output from the image converter plate;
• and
• an evaluation device, which determines the coordinates of the CO2 laser, when the detectable light is detected, compares the determined coordinates with predetermined reference coordinates, and calibrates the CO2 laser on the basis of the deviation between the determined coordinates and the reference coordinates.