| 摘要 |
PROBLEM TO BE SOLVED: To allow a user to easily discriminate a luminaire carrying out visible light communication from a normal luminaire by viewing it, and to prevent a sense of incongruity, such as flickers from being generated, in a visible-light communication system. SOLUTION: In the luminaire carrying out visible-light communication, a communication signal is transmitted by varying the amplitude of intensity of light emitted from a discharge lamp, by changing the frequency of a lamp current flowing to the discharge lamp between f1 and f2, and an information reception terminal extracts the communication signal based on the variation of the amplitude. The luminaire is structured, such that a transmission period Ds for transmitting the communication signal and a non-transmission period Dn, without transmitting the communication signal are repeated alternately, and the cycle T of the repeated periods is set not shorter than 1 sec. In the non-transmission period Dn, the light intensity is set to zero. Since the intensity of the light emitted from the luminaire for communication is varied in the transmission period Ds and the non-transmission period Dn to a level, allowing the user to visually recognize it, the luminaire for communication can be discriminated from normal luminaire, and sensation of flickers is not generated, because the cycle T of the variation of the light intensity is long. COPYRIGHT: (C)2009,JPO&INPIT |
