| 摘要 |
PURPOSE:To ensure the detection of the degree of a flaws without the effect of external light, by constituting a light projector so that alternating light is generated, removing a DC component and low frequency component from the light signal, which is extracted by a light receiving device, performing full wave rectification of only the alternating light, and taking out the result. CONSTITUTION:A light projector 3 has a lamp 6, which is conducted and lit, and a reflecting mirror 7. A disk 20, having slits is provided at a light converging part of a lens system comprising lenses 8 and 9. The disk 20 is driven and rotated by a motor 21 at a constant speed. The slits 20A are provided in the circumferential direction at a specified interval. Light is projected from the light projector 3 toward a flaw part to be detected of a glass bottle 2, which is moved in the specified direction. The DC component and the low frequency component are removed from the flaw signal detected by a light receiving device 4 through a DC signal removing circuit 22. The output of the circuit 22 undergoes full-wave rectification and smoothing 23, and the result is inputted to a comparing and judging circuit 15. The comparison is performed with a reference value set in the circuit 15, and the quality of the bottle is judged. Therefore, the degree of the flaw can be positively detected with the effect of the external light being removed. |
