LED display containing LEDs emitting invisible light

A light emitting diode (LED) display system, comprising:

• an LED display comprising an LED array, wherein the LED array comprises a plurality of infrared (IR) LEDs configured to emit IR light and a plurality of color LEDs configured to emit visible light;
• an LED driver connected to the LED array and configured to drive the LED array;
• and
• an infrared code reader signally connected to the LED array and comprises a photodiode, and a photodiode amplifier or a transimpedance amplifier,
• wherein the photodiode is configured to convert IR light emitted from the plurality of IR LEDs to a current signal, and the photodiode amplifier or transimpedance amplifier is configured to convert the current signals from the photodiode to a voltage signal;
• wherein the infrared code reader is configured to digitize the voltage signal to form a XY location code identifying a coordinate for each of one or more of the plurality of IR LEDs that emits the IR light, and to transmit the identified coordinate to the LED display,
• wherein the LED display is configured to cause one or more color LEDs at the identified coordinates to lit, thereby showing the location of the one or more of the plurality of IR LEDs that emitted IR light.