| 摘要 |
PURPOSE:To prevent sound interruption when an optical path is interrupted by detecting the presence of an optical signal from the light emitting element of other optical space transmitter and driving a 2nd light emitting element group fitted to the positions reflected on a wall face, a ceiling face and a floor face when no signal exists. CONSTITUTION:An amplifier circuit 6 amplifies a weak electric signal from a light receiving element 5, the presence of the signal is detected by a driving control circuit 7, and when no signal exists (at the interruption of the optical path by a person 15), a 1st driving circuit 3 is stopped to operate a 2nd driving circuit 8. Then a reflected light 11 on the wall face, ceiling face and floor face from 2nd light emitting element groups 9 being one set or above fitted to the position reflected on the wall face, ceiling face and floor face is transmitted to an optical space transmitter 14. |
