| 摘要 |
PROBLEM TO BE SOLVED: To increase the transmission range of an infrared beam by providing a means for condensing the beam on an infrared signal generating front position for a transmitter for generating an infrared signal superposed on a video/audio signal in a specified direction. SOLUTION: A condenser 8 has a concave lens in front of an infrared emitting LED of a LED drive 7. The lens of the condenser 8 condenses an infrared ray from the emitting LED of the drive 7 to emit a condensed infrared beam 9 toward an infrared receptor of a monitor 3 from the concave lens. If the distance between the emitting face of the emitting LED and the concave lens is equal to the focal length of this lens, the beam 9 is a collimated light and its cross sectional diameter is equal to the diameter of the lens. Thus the beam 9 is condensed to thereby increase the transmission range. |
