| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To accurately identify the type of a material to be detected with small restriction of the disposing position of the material. <P>SOLUTION: A first optical coupling unit 31 is disposed on the surface side of the material 33 to be detected. A first photodetector 44 photodetects light from a first photodetector 38 reflected by the material 33. A second optical coupling unit 32 is disposed on the rear surface side of the material 33. A second photodetector 57 photodetects light from a second light emitting element 51 reflected on the material 33. Further, the photodetector 44 photodetects the light from the second light emitting element 51 passed through the material 33. In this case, even when the material 33 moves in parallel, the output of the first photodetector 44 by the transmitted light of the material 33 does not almost change. Accordingly, the type of the material 33 can be accurately identified by comparing the transmittance of the material 33 with the reflectivity of the front side and the reflectivity of the rear side. Further, since the first and the second coupling units 31, 32 are separated from each other, the restriction of the material 33 at the disposing position is small. <P>COPYRIGHT: (C)2004,JPO</p> |
