| 摘要 |
PURPOSE:To perform flaw detection with a good S/N ratio, by darkening the surface of a member to be inspected and projecting illumination light to the darkened surface at a large incident angle while receiving reflected light returning to the incident side reflected light returning to the incident side in scattered reflected light. CONSTITUTION:The circumference of a surface 10 coming to a region to be inspected is blocked from liht to darken said surface 10 and illumination light B1 is projected to the surface 10 at a large incident angle near to 90 deg.. Because the surface 10 is a mirror surface one and the incident angle is large, almost all of projected light is regularily reflected from said surface if there is no projecting flaw and flies away to the side opposite to the incident side. Therefore, when the output of the TV camera 14 for observing the surface 10 is applied to a monitor TV receiver, the picture 18 of said receiver is dark and the image of the surface 10 is represented only obscurely. However, if there is a projecting flaw D on the surface 10, irregular reflection is generated and a part B2 thereof is returned to the incident side. This reflected light B2 is received by the TV camera 14 and a bright spot P appears on the picture 18 of the monitor TV receiver. The number of bright spots shows that of flaws and the size of each bright spot shows the size of each flaw. |
