| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a position detector for the surface and the rear, which can be applied to a marking apparatus which hardly damages the rear of an object to be marked. SOLUTION: A bolding base holds the object having a surface and a rear. Using a light source, a light-beam flux is made incident on the object held by the holding base from the side of the surface obliquely with respect to the surface. The light-beam flux emitted from the light source is reflected by the surface of the object, held by the holding base, and it turns into a first reflected light. It is refracted by the surface of the object, reflected by the rear of the object, refracted again by the surface of the object, and turns into a second reflected light. The first reflected light and the second reflected light are incident on the light-receiving face of a photodetector. The photodetector detects the position of a beam spot by the first reflected light and that of a beam spot by the second reflected light on the light-receiving face.</p> |
