Physics Behind LED Technology


Light emitting diodes, or LEDs, rocked the world of electronics. These tiny light bulbs have already been used for dozens of purposes and applied in practically all devices. Moreover, these days can be recognized through the invention of blue LED, which is the key way to obtain efficient and cheap lighting. The understanding of LED physics will help you realize why this technological innovation is that promising.

To see where the light is taken from, you should know how a diode works. Each diode consists of two crystallite layers: the first one with high-energy electrons, and the second with low-energy electrons. When a current is applied, the electrons flow from one layer to the other. At the junction between the layers, the photon energy is released. The energy difference between the layers is called the band gap. The first LEDs had a small band gap, and consequently, only the longer waves of red light were produced. That was enough to light up watches and calculator displays, show numbers on digital clocks, or to be used in remote controls.

Later, the scientists got to know how to make the LEDs with larger band gaps, and this is when the LED light spectrum broadened: from red, to orange, yellow, green, and finally, blue. Moreover, they learned to grow big crystals that could put out more light. In the late 1990s, three scientists from Japan managed to grow a crystal with a band gap large enough to produce blue light. Undoubtedly, that was a turning point in electronics.

The invention of blue LEDs made it possible to get white light. Phosphors were used to convert blue light into the spectrum of different colors. The combination of these colors can be seen as white light. This light is the same as the sun light, and undoubtedly, it can be used to illuminate houses.

The experiments proved that the modern LED light bulbs are much more efficient in comparison with the traditional incandescent lamps. They don’t have heating filaments that burn out, easily fit the electrical circuit, serve much longer than incandescent bulbs, and what is more, require less energy to produce the same amount of light.

LED technology has been changed and improved much since the days of being invented. Instead of being a scientific oddity, it promises to be the most efficient, comfortable and saving way of getting light into our lives. The LED light bulbs will apparently turn into the primary light sources in every house in a couple of years.