| 摘要 |
PURPOSE:To obtain an infrared-ray space transmitting device capable of transmitting to both of far and near distances with a simple constitution. CONSTITUTION:This transmitting device is provided with a transmitter 2 having plural light emitting elements 3 to be driven by a modulation signal modulated based upon a sound signal and an optical lens 1 for converging infrared rays emitted from the elements 3, converting the converged infrared rays into parallel beams and transmitting the parallel beams to a far distance and a receiver 4 for receiving the infrared rays projected from the elements 3 in the transmitter 2 by means of a light receiving element 5 and demodulating the received signal to obtain a sound signal and the lens 1 can be loaded/unloaded to/from an optical path. Thereby the device can correspond to transmission to both of far and near distances by inserting the lens 1 into the optical path in the case of a far distance and removing the lens 1 from the optical path in the case of a near distance. |
