| 摘要 |
PURPOSE:To avoid malfunction due to fluorescent light, by providing a band pass filter having the transmission rate - wavelength characteristics equal to the amount of light emission - wavelength characteristics of a light emitting diode in front of a photodetection diode, in an infrared ray type remote controller for television. CONSTITUTION:An input set with a keyboard 2 of a transmitter 1 is converted into a control signal Vc consisting of 8-bit digital signals at a code generating circuit 3 and modulated at a pulse modulation circuit 4, and a carrier signal Vs is generated and a light beam is emitted from a light emitting diode 5. A receiver 10 is provided with an infrared ray filter 11 comprising a band pass filter in front of a photodiode 12. A transmitting characteristic F1 of the filter 11 has a transmission-wavelength characteristic almost equal to the amount of light - wavelength characteristic of the diode 5, to constitute a band pass filter combining a high-cut filter and a low cut filter. Thus, disabled remote control operation of the photodiode 12 due to masking effect by a fluorescent light can be very less. |
