| 摘要 |
<p>PURPOSE:To obtain a regression-reflecting type photoelectric switch at a low cost without erroneous operations even for reflection with a mirror surface reflecting body, by using a GaAlAs heterojunction red-light emitting diode as a light projecting element. CONSTITUTION:At the outside of a lenses 2 and 7, a light projecting polarization filter 3 and light receiving polarization filter 6 each constituted by PVA are arranged. A lens cover 4 is coupled to a main body case 11 so as to cover the polarization filters 3 and 6. At this time, a GaAlAs heterojunction red-light emitting diode is used as a light projecting element 7 of a light projecting part. Since the GaAlAs heterojunction red-light emitting diode 1 is used in combination with the PVA visible-light polarization filters, infrared rays are not emitted from the light projecting part. Therefore, erroneous operation does not occur at a mirror surface reflecting body even if the low cost PVA visible-light polarization filters are used.</p> |
