US Patent 7929867 Emergency lamp and wireless emergency lamp data transmission system

An LED is used as a light source of the emergency light. Data are normally received through a power line, demodulated at a modem section, and stored in a data memory. In an emergency, a change sectio switches the power line to a battery, and LED emits light and functions as the emergency light. At this time, the data stored in the data memory is read and demodulated at a light modulation section, and used to control blinking of the LED and the light intensity. Thereby, the data can be transmitted by the light. In an emergency, information on an emergency exit, an escape route, etc. can be received, if a mobile terminal having a light-receiving section receives the light from the emergency light.