Have you ever heard LED Light cold and heat light source up to now or how much do you know about them? Now, let’s talk about the difference between them.
Cold light source is a kind of light source which is stimulated by chemical energy, electric energy or biological energy, such as firefly, neon light, LED Light, etc. It has very excellent specialty of optics and flicker. When an object gives out light and its temperature is not higher than environmental temperature, it is named as cold light source. For example, LED takes advantage of electron hole pair to compound light. Strictly speaking, even though LED (lighting emitting diode) also releases heat during glow, it is far lower than incandescent and other light source. The experimental data shows that the conversion efficiency between LED electricity and light is about 30%, and the efficiency of internal quantum is about 70% while external quantum is about 50%.
On the contrary, heat light source is a kind of light source which is stimulated by heat energy. For example, incandescent gives out light by heat radiation when the temperature is between 3000 and 4000K, and about 80%-90% energy is converted into heat energy, while only 10% energy is converted into light energy. This is the reason why the luminous efficiency is a little low. It’s no doubt that it cannot be defined as cold or heat light source only based on the temperature of the fixture shell, which is only to judge the quality of the heat dissipation of fixture.
Actually, cold light source doesn’t mean glow without heat energy. It means that the glow method is not to covert heat energy into light energy. Incandescent is a typical case that converts electricity energy into heat energy and then converts heat energy into light energy. Therefore, its heat energy losses a lot while the luminous efficiency is low. So far, more and more street light has been updated into LED Street Light . According to this development trend, the times that cold light source has completely replaced heat light source is not so far because LED Light could be regarded as cold light source.