LED stands for Light Emitting Diode.
For more information see LED
A new wave of lighting is now being produced that use multiple LEDs instead of traditional bulbs.
Originally these LED fixtures used low powered LEDs to create the light needed, for example a Par Can shell would be used to mount a board that contained 153 LEDs, this would have 51 each of Red, Green and Blue (RGB) and by varying the dimming level of each these colours you could produce lots of different colours.
Newer fixtures are now using 1W and 3W LEDs these are far more powerful than the original LEDs used and give of a more powerful light for less LEDs.
Due to the nature of LEDs in an RGB LED fixture it was very hard to produce a true white colour it always seems to have a slight blue hint to it. This has been overcome by producing units that have white LEDs. I have not seen any LED fixtures that have both the Red, Green, Blue and White LEDs in them together, they have always been seperate fixtures.
LED fixtures started as colour wash lights, but now due to clever lenses can be used as spots.
Another type of LED fixtures are colour bars, these vary in the number of LEDs and the size/power of LEDs used and depending on how they are manufactured will either be used as one light showing any single colour controlled by RGB or they might have many sections that can be individually controlled to produce a different colour controlled by RGB, obviously this type of fixture is far more expensive than the single colour variety. A lot of these Colour Bars can be linked enabling you to create impressive colour chase patterns.
LEDs are also being used in video wall displays. These can be small units from something like 16×16 pixels, each pixel being represented by at least 1 of each red, green and blue LED's, upto something like 256×256 pixels. These are then joined together, seamlessly to create a video wall. Depending on the manufacturer and specification these range from a few hundred pounds to thousands of pounds. LED video walls are used in a lot of televised music events, such as the X-Factor, most bands of fame usually have some sort of video wall on stage.
Advantages of using LEDs are low power consumption, you can get at least 10 LED Par Cans working from a single 13amp power socket. Due to this low power consumption they also give of very little heat so no need for fans to cool them and the life expectance is around 10,000 hours.
The price of LED equipment is falling all the time and I am sure we are going to get some very exciting LED fixtures in the near future that just have not been possible with conventional bulbs.