An LED display is a video display made up of light-emitting diodes, or LEDs. LEDs are small electronic devices which produce a very efficient light source. They are widely used in everyday devices from traffic lights to remote controls. Many LED displays are used outdoors in billboards and store signs.
A typical LED display is composed of many LED panels, which are sometimes used as a form of lighting or illumination rather than for display. Two classes of LED panels exist: conventional LED panels, which use discrete LEDs, and surface-mounted device (SMD) panels. Conventional panels are the more common of the two, especially for large outdoor display screens. In this type of LED panel, clusters of red, green, and blue LEDs are grouped together to form numerous square-shaped pixels.
SMD technology is usually used to construct an LED display which for use indoors. LED screens that utilize SMD also use red, green, and blue LEDs to A typical LED display is composed of many LED panels, which are themselves are sometimes used as a form of lighting or illumination rather than for display.form pixels, which are mounted on computer chips or very small circuit boards. These pixels are each very minute, with individual LEDs that are smaller than a pinhead. The main practical differences between the two are the decreased maximum viewing distance with SMD, as well as the slightly decreased brightness. These both make SMD the better LED technology for indoor applications.
The individual diodes which make up an LED display are themselves an important technological advance which offer many advantages over other lighting sources. An LED is made of a transparent plastic case around a semiconductor chip, which has positive and negative terminals leading to it. Electrons flow into the semiconductor chip, which -- because of its chemical nature -- causes the electrons to give off energy in the form of photons. We then perceive these photons as light. Different semiconductors will give off different colors of light, including infrared and ultraviolet light.
An LED has many advantages over traditional incandescent light, the typical light source in many homes. First, there is very little heat produced by an LED, as opposed to the large amount of heat produced by a tungsten light bulb. In a traditional light bulb, nearly half the energy is lost as heat. LED lights also use very little energy to operate. This makes them the light source of choice for devices such as traffic lights, which operate continuously.
The first LED display screens were developed in the late 1970s, and their inventors received awards and recognition at the 29th Engineering Exposition in Anaheim, California. At that time, however, the only LED display available was monochromatic, since an efficient blue LED had yet to be developed. Efficient blue LEDs were needed for color displays, and these finally emerged in the early 1990s.