| 摘要 |
PURPOSE:To achieve the improvement in mass productivity and the reduction of a cost by specifying the relation between a transmission type photosensor and a rotor thereby obtaining required performance despite the presence of variance in elements. CONSTITUTION:A transmission type photosensor 1 is of a U shape, and a light emitting element 2 and a photodetector 3 are incoporated on the inner side of its respective leading ends. A semiconductor light emitting diode (LED) is used for the element 2 and a phototransistor for the detector 3. Terminals 4, 5, 6 are for an electric power source, output and earth. Vane parts 8 of a rotor 7 are inserted between the light emitting and photodetecting parts of the photosensor 1, and when the rotor 1 revolves, the vanes 8a, 8b- shut off the light of the element 2 entering the detector 3 intermittently. In the sensor 1 and the rotor 7, the width of the photodetecting part of the photosensor is defined as (a), the spacing between the vanes of the rotor as (b), and the width of the vanes of the rotor as (c), and the (a), (b), (c) are so formed as to satisfy the conditions shown by the equations. |
