What is an LED and why is it growing in popularity?


In recent years, all of us have become familiar with the light emitting diode, or LED. We find LEDs in decorative lighting, handheld torches, backlighting for flat panel displays, as status indicators on a host of electronic products and even as car brake lamps and indicators. However, it’s only very recently that LED lamps have begun to appear as a general purpose light sources for domestic and commercial use. We’re just at the start of a revolution in such lighting. Traditional light bulbs are under attack from EU Directive 244 and other legislation aimed at reducing energy consumption. They will soon be consigned to history.


An LED is an electronic semiconductor device of a particular material composition which, when current passes through it, gives off light. The first practical LED to produce light with a spectrum visible to the human eye, a red LED, was discovered in 1962. In later developments, orange, yellow, green, blue and violet LED chips were created. The main technology challenge has been to maximize the amount of light produced with respect to the energy supplied to the LED.


The choice of LED lamps will grow over the next couple of years with most major vendors producing products for the retrofit market and are launching products with the most common fittings. Luminous efficacy of LEDs has reached the point where replacements for traditional 40W lamps are now available and replacements for incandescent bulbs rated at up to 100W will be on the market before the September 1st, 2012 deadline when all incandescent lamps will be banned by EU legislation.

Moreover, LED lamps are expected to replace most other forms of domestic and commercial lighting in the next few years. They do not only reduce energy costs, they also cut maintenance requirements and offer new opportunities for creativity in lighting installations.


Parts of an LED:

  • Lens- an optical piece that directs the light from the chip into the beam shape and direction.
  • Led Chip- is the semi conductor device that generates the light.
  • Lead- may be either one or two electrical links where current is applied.
  • Wire Bond- a wire that fixes the lead to the chip.
  • Encapsulant- a part of the LED that connects the chip to the lens.
  • Case- a covering that protects the LED