What is a LED?

A LED (acronym for light-emitting diode) is a light-emitting diode. In its interior there is a semiconductor that, when crossed by continuous voltage, emits light, which is known as electroluminescence. There are different types of LED depending on the technologies used for its manufacture and assembly on electronic circuits.

LED technology

The operation of a LED is based on the activation of a PN combination of an inorganic semiconductor material through an electric current. Depending on the semiconductor compound used, light emissions of different colours can be obtained. Let’s take a look at a table with the semiconductor compounds and the most common colours:

    • Color
    • Wave length(NM)
    • Compound
    • Infrared radiation
    • λ > 760 NM
    • Gallium arsenide (GaAs)

      Gallium-aluminium arsenide (AlGaAs)

    • Red
    • 610 NM < λ < 760 NM
    • Gallium-aluminium arsenide (AlGaAs)

      Gallium arsenide phosphide (GaAsP)

      Gallium-indium-aluminum phosphide (AlGaInP)

      Gallium phosphate (GaP)

    • Orange
    • 590 NM < λ < 610 NM
    • Gallium arsenide phosphide (GaAsP)

      Gallium-indium-aluminum phosphide (AlGaInP)

      Gallium phosphate (GaP)

    • Yellow
    • 570 NM < λ < 590 NM
    • Gallium arsenide phosphide (GaAsP))

      Gallium-indium-aluminum phosphide (AlGaInP)

      Gallium phosphate (GaP)

    • Green
    • 500 NM < λ < 570 NM
    • Gallium phosphate (GaP)

      Gallium-indium-aluminum phosphide (AlGaInP)


    • Blue
    • 450 NM < λ < 500 NM
    • Zinc Selenide (ZnSe)

      Indium gallium nitride (InGaN)

      Silicon carbide (SiC) as a substrate

    • Violet
    • 400 NM < λ < 450 NM
    • Indium gallium nitride (InGaN)

    • Ultraviolet
    • 570 NM < λ < 590 NM
    • Indium gallium nitride (InGaN) (385-400NM)

      Diamond (c) (235NM) 73

      Boron nitride (BN) (215NM)74 75

      Aluminum nitride (ALN)(210NM)76

    • Red
    • Combination of several
    • Blue wit one or two layers of phosphorus

      Yellow with red, orange or pink phosphorus

    • White
    • Wide spectrum
    • Zinc Selenide (ZnSe)

      Indium gallium nitride (InGaN)

      Silicon carbide (SiC) as a substrate


LED technology is very widespread. The first successful commercial use began with the infrared diodes that are used in the remote controls of all types of devices.

More recently, the use of LED-based lighting systems has had great acceptance due to its long life, low consumption and great durability.

Currently, the great advances in LED technology have allowed them to be used to create large dimension LED screens, mostly used for the emission of advertising and information in busy areas.

Its great advantages over other more conventional systems, has become a real attraction, as we can see more and more in our city’s streets and avenues.


There are several types of LED for advertising LED screens:


LED DIP (Dual in-line package)

It is a highly resistant encapsulated LED that emits only one colour. For that reason, we find them in LED panels forming the RGB tricolour set (with this combination all colours are created). These LEDs are a good option for outdoor LED screens, as they resist environmental factors and their great luminosity. The only drawback is their reduced viewing angle.


SMD LED (Surface-Mounted Device)

These LEDs combine the three RGB colours in one package. Thanks to this, we achieve small pixels with good viewing angles. These LEDs are used for both indoor screens and outdoor screens. Outdoor LEDs are less resistant and bright than DIPs.


Vandal resistant / Outdoor resistant LED

It combines the strength and durability of the DIP LED with the versatility and definition of the SMD LED. It has an additional protective encapsulation that protects the LED’s semiconductors. Its price is higher than the SMD or DIP LEDs.


  • Great environmental resistance
  • High levels of brightness
  • Best colour definition and quality than the conventional DIP
  • One encapsulation of 3 colours
  • Better vision in short distances
  • One encapsulation of 3 colours
  • Better image definition

Vandal resistant LED

  • The same advantages as the SMD LED
  • Additional epoxy case against impact or extreme climates