| 摘要 |
PURPOSE:To improve the detection efficiency of a flaw by finishing up the peripheral surface reflected to an object to be inspected to a color so as to make a complementary color relation with a light color of a light source for inspection and illuminating it so as to obtain a color contrast in addition to a brightness contrast. CONSTITUTION:The surface of the object 1 to be inspected has a mirror reflection characteristic and the flaw 2 has a diffused reflection characteristic. The light color of the light source 5 for inspection is, for instance, yellow and the surface of a board 6 is finished up to blue to make the complementary color with the light color of the light source 5. Further, white light sources 7 and 8 illuminate the board 6, and light shielding plates 9 and 10 are made so that light beams of the light sources 7 and 8 are not made incident on the object 1 to be inspected. Since there is the complementary relation between the diffused reflected light L2 from the light source 5 on the flaw 2 and the mirror reflected light L3 from the board 6 on a part which is not flawed, the color contrast which is easily identifiable for the eyes 4 of an inspector can be obtained. Further, when the illumination levels of the light sources 7 and 8 are made stable and properly low, the brightness contrast of the flaw 2 and its periphery is not lost. |
