| 摘要 |
PURPOSE:To remove stray light by switching the spectrum of the light emitted from one multiple light emitting diode in correspondence with the sensitivity distribution of a detector. CONSTITUTION:The multiple light emitting diode 8, which generates level signal, is a single element. When a voltage is applied across terminals A and C1, the spectrum of the light with a wavelength of lambda1 is outputted from the diode 8. When the voltage is applied across terminals A and C2, the spectrum of light with a wavelength lambda2 is outputted. The signal from the diode 8 is detected by a detector 9 and transformed into a gate signal. A control element 11 turns OFF relays Ry1 and Ry2 in the region of a detector 5, and operates the relays Ry1 and Ry2 in the region of a detector 6. In the region of the detector 5, the relay Ry2 is operated, and a mirror M15 is inserted in front of a detector 5. Then the light is irradiated to the detector 6. At this time, since the detector 6 does not have sensitivity for the spectrum having a peak in the wavelength lambda1, the stray light is not produced. |
