Abstract: A tricolor LED display system (10) is provided having a plurality of multi-color LEDs (22) that operate as concurrent display and data communication elements. These dual-use tricolor LEDs are coupled to a special-purpose computer system (12) and audio signal transmitter (16) for simultaneously controlling the visible display signal from the LEDs, and for modulating audio information onto the visible light signal emitted by the LEDs. A receiver circuit (24) receives the modulated visible light signal from the LEDs and demodulates the received signal to recover the audio information, which is then presented to a user of the system through an audio interface.

Abstract: A dot matrix display system made up of light emitting diodes (LED's), n which one or more LEDs are modulated and encoded with audio information or messages is disclosed. The system has a LED dot matrix display panel with an interface circuit to a computer, an audio signal transmitter, and a receiver. An executive program runs on the computer for the visual display control of characters, decorative pattern or messages on the display panel. The receiver combined with a speaker is located at a distance from the display panel. The receiver is designed to demodulate the optically transmitted audio information and broadcast the messages with the speaker. The modulation of the LEDs includes a voltage-controlled oscillator (VCO) for varying the frequency of on/off periods of said light emitting diodes. The frequency is high enough such that the perceivable light appears to be constantly illuminated to the human eye.

Abstract: A handy information display system is disclosed. The system has three main components: a light emitting diodes (LED) array display board, an information server and a portable unit. The LED array display board includes a plurality of light emitting diodes and photodetectors. It can be used to display alphabets, numbers and simple graphics. While it visually gives an effectively stationary message display, the LED can also be modulated to transmit high frequency signals. The modulating frequency should be high enough to be imperceptible by humans. Both message display and signal transmission are controlled by an information server. The system further comprises at least one portable unit. The portable unit is equipped with an optical transceiver and a visual display unit. The optical transceiver can detect the signals transmitted from the LED array display board. The visual display unit then shows the information corresponding to the received signals.