| 摘要 |
<p>PURPOSE:To downsize an apparatus by dividing a luminous flux projected to a plate to be inspected in half by a first translucent mirror, and receiving the light through a second translucent mirror. CONSTITUTION:A luminous flux generated from a light source 4 is collected by a projecting lens 5, so that a light spot is projected to a plate 1 to be inspected. At this time, owing to first translucent mirrors 121, 123... 12n provided in an optical path of the projecting light, the light beam is divided in two and projected to measuring points M0, M1, M2... Mn on the plate 1. Accordingly, the projecting means 101-10m can be reduced half the necessary measuring number of times. Similarly, for a photodetecting means 11 consisting of a photodetecting lens 6 and a detecting device 7, second translucent mirrors 122, 124... 12n+1 are provided in a path of the detecting light, thereby to receive a light spot reflected at two points on the plate 1. Therefore, the photodetecting means 111-11m can also be reduced to half the necessary measuring number of times. Assuming that the necessary measuring number of times is N, the number of the photodetecting means (m) becomes m=(N+1)/2 as a whole, making the apparatus compact in size.</p> |
