Problem diagnosis method and problem repair method for laser device

A problem repair method for a laser device that includes a beam generator outputting a laser beam, an optical sensor receiving a scattered laser beam generated by an optical part disposed inside or outside of the beam generator and outputting electrical signals corresponding to an intensity of the scattered laser beam, a prediction control unit predicting a seriousness of a problem which occurs on the optical part based on the electrical signals outputted from the optical sensor, and an automatic repair unit receiving control signals outputted from the prediction control unit and moving the optical part based on the control signals, the problem repair method comprising the steps of:

• predicting a temporal change in the intensity of the scattered laser beam generated by the optical part based on operating conditions of the laser device;
• measuring the intensity of the scattered laser beam generated by the optical part;
• referring to data indicating the temporal change in the intensity of the scattered laser beam predicted under the operating conditions and predicting the seriousness of the problem occurring on the optical part by comparing the intensity of the scattered laser beam that is measured with the data indicating the temporal change in the intensity of the scattered laser beam that is predicted;
• determining what kind of maintenance work is necessary based on the seriousness of the problem that is predicted;
• and
• moving the optical part such that the intensity of the scattered laser beam generated by the optical part decreases, based on the maintenance work that is determined to be necessary.