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.
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.
Types of LED light
LED is manufactured in a variety of shapes and sizes that are enclosed in plastic casing that indicates the color of its light. Some time transparent casing is used to radiate light efficiently. The different types of LED used are:
Miniature, which is a very small size LED used as an indicator and shaped in a round or rectangular form.
Mid-range, which is a medium power LED which has a higher current and is used in light panels or emergency lighting.
High-power, which is a high power density LED driven by a higher current and which requires a heat sink to operate. It can be used as flashlight or powerful lamp.
Benefits of LED
If you look back towards each lighting technology, you will find LED lighting to be the most energy efficient, eco-friendly and pleasant illuminating technology. Its benefits include:
- Long life and energy efficient: These lights don’t usually burn out and continuously serve for a long period. Also, it converts 90% of input energy into light and that makes it the most efficient option.
- Eco-friendly and durable: LED doesn’t leave any toxic materials and this helps to keep environment green. LED is made up of sturdy component, which is resistant to shock and impact and thus, can withstand the toughest condition.
- Flexible and adaptable: LED can be molded into any interesting shape and radiates the color that suits your mood. These lights behave ideally under any temperature.
- Instant lighting and low voltage: LED is designed to operate in low voltage and brighten up immediately when power is ON.
- Focused and zero UV emission: LED lights are highly focused towards desired application and have near zero ultra-violet emission. This makes them beneficial to illuminate sensitive objects in galleries or museums.
Light emitting diode facts: - LED has a lifetime of more than 25,000 hours. If you use LED fixture continuously 8h/day then it will serve you around 20 years.
- 90% efficient.80% of your electricity bill is just to heat the room and the rest is to light it up. Using LED will reduce your bill from $100 to an amazing $20.
- According to one report, in 2012, about 49 million of LED lights are installed in the US that result in saving about $675 million in one year in energy costs.
- LED is the safest way to illuminate a wet application like underwater lighting, swimming pool lighting and aquarium lighting.
- LED are bright and efficient and save your electricity if you opt to light it by solar panel.
LED lighting technology is continuously advancing in terms of manufacturing techniques. It is designed in several forms to lighten thousands of application. Scientists are developing organic and quantum dot LED’s which will surely result in reduction of cost and improvement in performance of LED technology. So next time when you hold a LED, you are surely familiar with the science behind its illumination.