LEDs are an inexhaustible subject, when it comes to bulbs. What are LEDs really? First of all, to talk to LED in a shortcut by “Light emitting diode” or very exact “light-emitting diode”. Specifically, it is a cutting-edge source of light without UV – and infrared radiation. With a very high lifetime of the part to more than 50,000 hours, about six years, and a small construction provide a variety of LEDs.
The invention of the LED
The LED laid the foundation stone for the development of Ferdinand Braun, after he gave a lecture about the direction of current through crystals in 1876. In the following, this effect was rediscovered several times, but never ultimately led to the invention of the LED. (Source: Ledbulbbay)
Only with the development of the transistor, there was significant progress in semiconductor physics, which ultimately meant that the process of light emission could be clarified further. Some sources ascribe the invention of the light-emitting diode Nick Holonyak in 1962 as a result.
The enormous improvements in the quality of light of the LEDs in a short time are based especially on the improvement of semiconductor technology. in 1988 and 1992 the first was the production of a suitable for mass production vertreibbaren blue LED. Almost 25 years later was awarded for the Nobel Prize to Japanese developers. But it should take another ten years until beginning of 2000s the LEDs experienced a commercial boom with.
The service life of LEDs
With approximately 50,000 hours of lighting, light-emitting diodes are About six years without a loss can be used. Then, LEDs are usually weaker, but not completely fail. You must value specifying the so-called life on the basis of a 100% brightness. Then expects a reduction to 70-80%. There’s a simple definition to specify of this time period: approximately 50% of the light-emitting diodes must have still a luminosity according to the specified lifetime of at least 70%.
Of course, there are other environmental factors, which are responsible for the life of the LEDs. This includes in particular the temperature in the LED chip. How strong is the light falloff is crucial for this. The higher the temperature, the shorter the life. Special high power LEDs that provide an optimum dissipation of heat from the semiconductor circuit are the solution.
How economic are LEDs?
Light-emitting diodes have particular advantages. As the light output per watt is now much higher than in standard or halogen lamps, are very economical LED dimmable. There are specific terms of currently between 20 lm/W and 100 lm/Watt. Light bulbs are for example, 8lm / WATt. Due to the constant development the luminosity LEDs doubles about every two years.
Also, it is advantageous that the light of light-emitting diodes contains no UV radiation and no heat. The efficiency of the LED is relatively high, so that no heat is generated, but nevertheless heatsink must be used on high performance light-emitting diodes, because heat meets on a very small area. Still, it is interesting that LED are resistant to shock and vibration and DC operation, longer cable lengths are possible.
LED light colors
The impression of colour, created from direct invasion of the human eye, is called light color a light source. Monochromatic light is represented by the dominant wavelength. For LEDs, the monochrome light color is determined by the built-in semiconductor. The whole inner workings of a modern light-emitting diode is quite complex, so that can cause colour variations, even if an older LED unused LED of same production batch will be replaced by one.
In principle, LEDs can lumineszieren in all colors.