Patent ID: 8749168

Claim:
An illumination light communication device comprising: a light source unit including light emitting elements; a power supply unit which controls a load current flowing through the light source unit to be maintained at a constant value; a switch element connected in series to the light source unit; and a control unit configured to control on/off of the switch element to modulate a light intensity of illumination light from the light source unit such that a binary communication signal is superimposed on the illumination light, wherein the control unit has a switching circuit to open and close a path connecting between the light source unit and the power supply unit, controls on/off of the switching circuit based on a dimming signal to perform a dimming control on the illumination light from the light source unit by a PWM control, and allows the communication signal to be superimposed on the illumination light from the light source unit in synchronization with an ON time of the switching circuit.