subject: LED lighting technology [print this page] LED lighting technology LED lighting technology
LED is an acronym for Light Emitting Diode and this is a source of semiconductor light. These LEDS are mainly used for lighting purpose and used as an indicator device in most of the lights. In 1962, it was first introduced as an electronic component which was able to produce only red lights. But later and modern versions produces more colors.
Leds are the replacements of the traditional incandescent lights and it has many advantages and disadvantages compared to the traditional one. Advantages includes,
Robustness
Longer life up to 100000 hours because they doesn't have filaments.
Reduced and lower energy consumption and still delivers the needed output
Durability and Safety
Reliability
Smaller size
Switching is faster
Highly Efficient
Eliminate the need for usual bulbs
Follows 80-20% rule. - 80% of the energy is converted in to light energy and 20% is converted in to heat energy and thus produces a high efficient brightness.
Can be used with any measure of power supply and clapse
More advantageous than the high pressure sodium or metal lamps
High quality and flexibilty
Less light wastage
Steady beam of direct light in different directions
Disadvantages includes,
Heat management
Expensive
Needed more power supply
Directional leds may not be good enough for all settings
Technology behind it
The diode can be used in two modes.
Forward Biased or Switched on
2.Backward Biased. or Switched off
Whenever the diode is in forward biased mode, it produces a effect called electroluminescence in which, the electrons combines with the spaces/holes in the device and releases photons. In this scenario, the light's color is determined by the semiconductor's energy gap.
We are using modern leds in our day to day life like traffic signal lights, indicators and aviation lighting. Leds that are coming in compact size are used in sensors and high switching rates are used in communication technologies like televisions remotes that are highly advanced.
The first led was used as a replacement of neon and incandescent indicator lamps in Seven segment displays. Initially it was tested in larger laboratories and research centers. Later on, it was implemented in electronic medias like televisions, radios, watches, calculators, phones etc., As we very well know, red leds were the first leds introduced. This was first invented by Monsanto company and they used a chemical called gallium arsenide phosphide to produce red led indicators. Later on, they used a semiconductor material like compound semiconductor chips that are fabricated to produce high bright and high efficiency leds.
Parameters
Leds are designed to use maximum of 30-60 milli watts of electric power. In the last century, in 1999, Philips lumileds introduced a high power watt that can electric power of 1 watts.
