Light emitting diodes or rather LEDs for short is a simple device that we owe a lot to. They have revolutionized modern electronics in quite the way. They can have many different functions and you can even find the in almost every device. Among these devices would be transmit info remote controls, light up watches and digital clocks. They even serve the function to inform you when the appliance in turned on. When many diodes are formed up together, they can become as one whole display screen on a TV or on traffic light signs.
So to put it simply, LEDs are really just little light bulbs that you can place in easily into any electrical circuit. However, compared to incandescent bulbs, LEDs don’t contain a filament that would burn out. They don’t even get that hot. Their illumination comes solely from the electron movement that goes through its semiconductor material and can last equally as long as the normal transistor. The LED’s lifespan is far longer than the life of incandescent bulbs by thousands of hours. As of now, LEDs are already being incorporated into LCD HDTVs in order to come up with even thinner televisions.
So what really is a diode? Well, it is the simplest form of semiconductor device there is today. In addition to that, a semiconductor is a sort of material whose abilities can vary when conducting an electrical current. Usually the semiconductors in use today have a low grade conductor and even have some impurities like other materials being added to it. This process of mixing in the impurities is called doping.
In our LEDs however, the material used in it is aluminum-gallium-arsenide which is entirely pure. All of these atoms easily bond with their companion elements. This means there are no free electrons to conduct any current. In doped semiconductors, the additional atoms will cause a change in balance, either putting in free electrons or making holes where the electrons go through. These alterations in the materials can make the material itself more conductive to electricity.
But how does it produce all this light? Well, light as we know it is a form of energy that atoms can release. It is composed of many small particles that contain momentum and energy but have no mass. We call these particles photons, and they are the most basic unit of light there is.
Photons are emitted due to the movement of electrons. We find that in atoms, the electrons move in orbit around the nucleus. So as the electrons are moving through the diode itself, it is creating photons and released to what we see as light.
Even though every diode emits light, most don’t even do a good job at it. In a plain ordinary diode, the material just sucks up most of the light energy.
LEDs, however, are designed to release a lot of photons away from it. In addition to that, they are kept in a small plastic bulb which can focus the light to one direction.