LED displays are simply arrays of light emitting diodes that are interconnected to create a flat panel display. A light emitting diode (LED) is an optical PN-junction diode. This solid state diode emits light energy through electroluminescence when it is forward biased. Displays made from these optical diodes change depending on the combinations used to create a graphical pattern.

A seven-segment display is made up of seven LEDs (or eight LEDs when a decimal point is required). Only the forward biased diodes of a display emit light. Therefore, graphical patterns are created by lighting selected LEDs. Combining seven-segment displays produces panels whose size depends on the intended application. Seven-segment LED displays are suitable for displaying various alphanumeric characters.

Apart from seven-segment LED displays, we also have nine-segment displays, fourteen-segment displays, and sixteen-segment displays. These displays allow representations of various graphical patterns with less ambiguity. Color variations in LED segmented displays are determined by the PN-junction diodes used. The color emitted by an LED is a factor of the spectral wavelength of the light that it emits. These spectral wavelengths are determined by the impurities used to dope the semiconductor materials that make a diode. LED displays have numerous indoor and outdoor applications. They are widely used in various electronic appliances and commercial street advertisements.