INSPECTION DEVICE FOR FLAW OF TRANSPARENT SHEET-LIKE OBJECT AND FLAW INSPECTING METHOD OF TRANSPARENT SHEET-LIKE OBJECT USING SAID DEVICE

摘要

PURPOSE:To enable easy identification of a flaw existing in a transparent sheet-like object by combining a spot light source device and a screen in such a way that the transparent sheet-like object is placed inbetween in contact with neigher of them and projecting the flaw existing in the transparent sheet-like object on the screen thereby detecting the flaw. CONSTITUTION:A spot light source 1 of a spot light source device emits exit light 2 in three-dimensional directions and projects an image of an inspecting object through a transparent sheet-like material 3 on a screen 4. The light emitted from the source 1 is scattered in the flaw existing in the object to be inspected by which the light transparency in the flaw part is decreased and the flaw part is projected in the form of a shadow on the screen 4. Since the spot light source device, the screen and the transparent sheet-like object are disposed in the positional relation satisfying the equation I, the light 2 of the light source 1 forms the projecting image on the screen 4 by magnifying the flaw existing in the object to be inspected thereby making the contrast between brightness and darkness sharper. Not only the visual inspection but also the detection by mechanical reading are made possible.