What is the physical princible behind the LED light
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passive101
Enlightened
- Joined
- Aug 15, 2007
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the lights actually to heat up they have heat sinks to dissipate heat. Heat also comes out the front of them as the light is energy as well.
Joe Talmadge
Flashlight Enthusiast
Incandescent bulbs give off light because they're hot -- if they're not hot enough, no light comes out. LEDs give off light based on a totally different principle, and get hot incidentally, but don't need heat to give off light
B0wz3r
Flashlight Enthusiast
My knowledge of it is superficial at best; I'm sure we have other members here who have a much better grasp and can give a much better explanation. But, AFAIK, there are a couple of layers involved, and one of them has a sort of pitted like surface. As charge is run through the two surfaces, it causes electrons from on surface to go into those pits on the other surface, kicking out a photon as a result. That's about as much as I know about it though.
Moonshadow
Enlightened
Everything you need to know here:
http://en.wikipedia.org/wiki/Light-emitting_diode
LEDs are based on junctions between two semiconductors with differing energy bands - as electrons jump from one side to the other they lose energy and this energy comes out as light of a specific wavelength. One photon per electron, with the wavelength depending on the energy difference.
White LEDs used in torches are based on a blue emitter coated with a phosphor which converts some of the energy into other wavelengths, as described in Section 3.2.2 of the article (Phosphor-based LEDs).
As with any device, the process is not 100% efficient, so not all of the energy is converted into light. Some of the energy used comes out as heat, but much less than with an incandescent bulb.
http://en.wikipedia.org/wiki/Light-emitting_diode
LEDs are based on junctions between two semiconductors with differing energy bands - as electrons jump from one side to the other they lose energy and this energy comes out as light of a specific wavelength. One photon per electron, with the wavelength depending on the energy difference.
White LEDs used in torches are based on a blue emitter coated with a phosphor which converts some of the energy into other wavelengths, as described in Section 3.2.2 of the article (Phosphor-based LEDs).
As with any device, the process is not 100% efficient, so not all of the energy is converted into light. Some of the energy used comes out as heat, but much less than with an incandescent bulb.
SkyPup
Newly Enlightened
Where there is light, there is heat...
Apollo Cree
Enlightened
Electrons flowing through a LED emit light as they travel through a certain part of the diode. It involves quantum mechanics, but the electron jumps from one energy level to another and the lost energy produces a photon. A photon is a "particle" of light.
Incandescent bulbs emit light because the filament is hot. This actually emits light from electrons changing energy levels as well, but it's heat that puts the electrons in the higher energy states so they can drop back and emit light.
Gas discharge tubes work like LEDs in some sense, but they have to heat the gas up to high temperatures before the current will flow, so they have to be hot to start with.
All of these forms of light emitter heat up due to current flow, light that doesn't make it out of the device, and other forms of energy loss.
Incandescent bulbs emit light because the filament is hot. This actually emits light from electrons changing energy levels as well, but it's heat that puts the electrons in the higher energy states so they can drop back and emit light.
Gas discharge tubes work like LEDs in some sense, but they have to heat the gas up to high temperatures before the current will flow, so they have to be hot to start with.
All of these forms of light emitter heat up due to current flow, light that doesn't make it out of the device, and other forms of energy loss.
