LED is a tiny light source that twinkles in many applications that surround you. You have probably seen it around your Christmas tree, in digital clocks, the flashlight of your Smartphone or the lights in your luxurious swimming pool. This easy to use and commonly available light source looks usual but has some solid physics behind its radiance LED Display
Knowing the science behind this cool light will surely result in stepping-up your knowledge when you again hold an LED device in your hand. So let’s explore it:
What is LED?
LED is actually an acronym for ‘Light Emitting Diode’, which uses ‘Solid State Lighting’ technology to emit monochromatic light.
For those who are novices to physics, ‘Diode’ is a two terminal electronic component made from semiconductor material. This solid matter inside the diode when energized, starts to emit light and so the technology is called solid state lighting.
History behind LED
The revolution of LED light is originated by the discovery of the phenomenon termed ‘Electroluminescence‘ in 1907. Technically it’s a basic working principle of LED. Infrared is observed as the first light emitted from diode. The first color visible through LED was red and was developed by Nick Holonyak in 1962. Thus, he is also considered the “Father of LED”. From then till today, the discovery of various semiconductor materials and invention of several technologies makes LED emit a spectrum of light through it.
What is LED light technology?
LED technology is completely based upon the semiconductors electronic theory. So to understand it completely, one requires in-depth knowledge of semiconductor physics. In a simpler way it can be explained as-
There are basically two types of semiconductor material in term of energy band I.e., indirect band gap like silicon and direct band gap like gallium. LED is basically made with a combination of direct band gap materials. These material junctions when energized with voltage source releases energy in the form of photon I.e., packet of light. Different color from LED depends upon the band gap energy of the material.
What are led light bulbs made of?
LED is the smallest form of light source available and constructed to a diameter of around 0.25 inch. Various combinations of semiconductor material like gallium-arsenide, gallium-nitride, and indium-gallium-nitride are used to construct its solid state assembly. These materials emit light of different wavelength that makes a variety of color emission possible through LED.
The chips formed by these materials are then encapsulated in transparent or color molded plastic shells that give it the final commercial touch.
Color emitting theory of LED
What makes LED light so popular is its availability in every possible pleasing color. You can have any color of your choice to enlighten your surroundings. Now, what’s the science behind it? As we already know; color emission will be depend upon the wavelength of light emitted by LED’s semiconductor material. So material and technique differ to obtain the color of choice. Some examples for you are:
White light: There are two ways to obtain a white light; either coating ultra violet chip with phosphor or by RGB (Red, Green, and Blue) system in which light from multiple LED is mixed to results in a white light. The color quality produced by white LED makes it the best alternative for traditional bulbs and CFL lights.
Blue light: To obtain a cool blue light from LED wide band gap semiconductor such as GaN and InGaN are used. By varying the fraction of these materials ranges of blue shade from violet to amber can be emitted.
Red, Blue, Green, Amber and Yellow are commonly available colors in LED; however, every color within the visible spectrum range can be obtained by several such manufacturing processes.