Optical communication system, optical reader, and method of reading information

摘要

An optical communication system includes at least one optical ID tag (2 1 ) and at least one optical reader. Identification information is communicated between the optical ID tag (2 1 ) and the optical reader using light as a communication medium. The optical ID tag (2 1 ) includes storing means (14) for storing the identification information; reflecting means (21) for reflecting incident light in the incident direction; and modulating means (22) for modulating reflected light on the basis of the identification information stored in the storing means (14). The optical reader includes random number generating means for generating a random number; emitting means for emitting light having an oscillation frequency specific to the generated random number; photoelectric conversion means for performing photoelectric conversion to the reflected light incident in the emitting direction; extracting means for extracting a signal component having the oscillation frequency from the signal resulting from the photoelectric conversion; and demodulating means for demodulating the signal component.