| 摘要 |
PURPOSE:To offer the light receiving device which suppresses disturbance light by a simple configuration and realizes wider directivity characteristics at low cost. CONSTITUTION:The light L from a light source 21 is led to a first light receiving part 22 and a second light receiving part 23. A filter 25 in the first light receiving part 22 transmits light having the wavelength of the wavelength region of the light L or longer. A filter 27 in the second light receiving part 23 transmits light having longer wavelength than the wavelength region of the light L. Therefore, in the second light receiving part 23, a disturbance light LR having longer wavelength than that of the light L is received and is converted into an electric signal. Thus, the signal that the components of the disturbance light LR are removed can be obtained by detecting the difference of the output signals from the first and second light receiving part 22 and 23 in a detection part 24. |
