レーザ拡散法によるアルミナセラミックスクラックの自動検出

抄録

A non-contact technique to detect a narrow crack on a ceramic plate has been developed. When a laser spot with the diameter of about 15 μm is illuminated on a ceramic plate, the laser is diffused within the ceramics and interrupted by the crack. The crack is detected automatically by detecting the difference of irradiants on each side of the crack. A TV-camera is used to detect the distribution of irradiant on the ceramics. Windows set on TV-image integrate output signals, and the difference of signals at two windows is obtained. The optimum position and size are discussed. Some cracks are tested using the experimental apparatus. Experimental results show that this crack detection technique detects the cracks of 0.5 μm at an S/N ratio of 2.