LED’s, Short for Light Emitting Diodes are semiconductor devices that emit light when an electrical current is passed through it.
Who invented them
James R. Biard and Gary Pittman Discovered the LED in 1961. TI (Texas Instruments) was the first to patent the LED.
How they were invented
LED’s were developed by engineers who were experimenting with p/n junctions. These p/n junctions were being developed as diodes. Diodes allow current to flow in one direction but not the other. It through a race by many different companies to come up with what are called semiconductors for power control and laser technology that LEDs were invented. While trying to make an X-band GaAs varactor diode, they created tunnel diodes. Tunnel diodes are a type of semiconductor that is capable of extremely fast operation made possible by using quantum mechanical effects called tunneling. They placed the tunnel diode on a GaAs substrate which is a semiconductor with a zinc blended crystal structure and discovered that there must be light production going on during forward bias operation, so using an infrared detector, they tested it and found that what are now known as LEDs lit up brightly. The first LEDs sold for $130 each in 1962. So ironically rather than someone trying to invent this technology it was more of something that was kind of stumbled upon, like many other technologies.
Figure 1: Parts of an LED diode. (Taken from Wikipedia.com)
Figure 2: Electrical Schematic and physical repreesntation of a Light Emmiting Diode.
Why they are growing so popular
LED’s are designed so well, that they can be more efficient, longer lasting, and are actually more durable than incandescent and compact florescent lights. Also LEDs produce much more light per their size and do not loose as much energy to heat when compared to a traditional filament lamp. For this reason, LED’s are gaining popularity and are being used in all industries including lights for vehicles, household appliances, small electronics, and even general household and commercial lighting. Often times household incandescent bulbs produce a yellow hue. Modern LEDs used in home lighting often give off a white-like color and sometimes are viewed as looking "sterile". The most common colors of LEDs used in electronics are amber, red, green, and blue. Special types of LEDs are even able to change colors by the press of a remote.
LED colors are utilized in industrial environments on machinery to indicate important objects or notifications such as signal lights and power buttons. LEDs are also used as indicators within machinery to indicate a state of an input or and output of computers. LEDs are commonly referred to as a directional light meaning that the light emitted goes straight out through the lens or in other words has a uniform light dispersion. Meaning that the light that comes from these are more focused in a specific direction where as other bulbs produce an all-encompassing light which makes them not as bright. This means that LEDs can be utilized in flashlights without needing a reflective lens to direct the light beam. Given the LED is a solid-state semiconductor, they typically do not burn out like other bulbs do. As time goes on LEDs become dimmer and the shade of light produced changes. So to figure out the life expectancy of incandescent and CFLs they take a large number of bulbs and run them until 50% of them have burned out and that determines the life expectancy of those bulbs. To Figure out the life expectancy of LEDs they do the same as what is done with other bulbs but run them until they have dimmed by 30%. Since the time that LEDs were invented many improvements have been made to them and they will continue to progress.
Industrial Uses of LEDs
Many commercial and industrial factories are utilizing LED lighting in their facilities given the improved light output and bright white illumination is preferred over conventional incandescent lamps and florescent lamps.
Commercial Uses of LEDs
LEDs have gained popularity in Christmas decorations due to their bright colors and because the current draw from LED light strings is so low that there is less risk of fire and overloading an electrical circuit.
Color Changing LED strip for decoration or multimedia experience.
LED’s, Short for Light Emitting Diodes are semiconductor devices that emit light when an electrical current is passed through it.
Who invented them
James R. Biard and Gary Pittman Discovered the LED in 1961. TI (Texas Instruments) was the first to patent the LED.
How they were invented
LED’s were developed by engineers who were experimenting with p/n junctions. These p/n junctions were being developed as diodes. Diodes allow current to flow in one direction but not the other. It through a race by many different companies to come up with what are called semiconductors for power control and laser technology that LEDs were invented. While trying to make an X-band GaAs varactor diode, they created tunnel diodes. Tunnel diodes are a type of semiconductor that is capable of extremely fast operation made possible by using quantum mechanical effects called tunneling. They placed the tunnel diode on a GaAs substrate which is a semiconductor with a zinc blended crystal structure and discovered that there must be light production going on during forward bias operation, so using an infrared detector, they tested it and found that what are now known as LEDs lit up brightly. The first LEDs sold for $130 each in 1962. So ironically rather than someone trying to invent this technology it was more of something that was kind of stumbled upon, like many other technologies.
Why they are growing so popular
LED’s are designed so well, that they can be more efficient, longer lasting, and are actually more durable than incandescent and compact florescent lights. Also LEDs produce much more light per their size and do not loose as much energy to heat when compared to a traditional filament lamp. For this reason, LED’s are gaining popularity and are being used in all industries including lights for vehicles, household appliances, small electronics, and even general household and commercial lighting. Often times household incandescent bulbs produce a yellow hue. Modern LEDs used in home lighting often give off a white-like color and sometimes are viewed as looking "sterile". The most common colors of LEDs used in electronics are amber, red, green, and blue. Special types of LEDs are even able to change colors by the press of a remote.
LED colors are utilized in industrial environments on machinery to indicate important objects or notifications such as signal lights and power buttons. LEDs are also used as indicators within machinery to indicate a state of an input or and output of computers. LEDs are commonly referred to as a directional light meaning that the light emitted goes straight out through the lens or in other words has a uniform light dispersion. Meaning that the light that comes from these are more focused in a specific direction where as other bulbs produce an all-encompassing light which makes them not as bright. This means that LEDs can be utilized in flashlights without needing a reflective lens to direct the light beam. Given the LED is a solid-state semiconductor, they typically do not burn out like other bulbs do. As time goes on LEDs become dimmer and the shade of light produced changes. So to figure out the life expectancy of incandescent and CFLs they take a large number of bulbs and run them until 50% of them have burned out and that determines the life expectancy of those bulbs. To Figure out the life expectancy of LEDs they do the same as what is done with other bulbs but run them until they have dimmed by 30%. Since the time that LEDs were invented many improvements have been made to them and they will continue to progress.
Industrial Uses of LEDs
Many commercial and industrial factories are utilizing LED lighting in their facilities given the improved light output and bright white illumination is preferred over conventional incandescent lamps and florescent lamps.
Commercial Uses of LEDs
LEDs have gained popularity in Christmas decorations due to their bright colors and because the current draw from LED light strings is so low that there is less risk of fire and overloading an electrical circuit.
Additional Resources
References
How LEDs work (n.d.) Retrieved March 17, 2017, from http://www3.nd.edu/~leds/how/How.htmHow LED Light Bulbs Work. (n.d.). Retrieved March 17,2017, from http://science.howstuffworks.com/environmental/green-tech/sustainable/led-light-bulb.htm?utm_source=Outbrain&utm_medium=Referral&utm_campaign=OutbrainOrganicTraffic=obnetwork
Learn About LED Bulbs. (n.d.). Retrieved February 20, 2017, from https://www.energystar.gov/products/lighting_fans/light_bulbs/learn_about_led_bulbs
Center, C. 2. (n.d.). LED Lights - How it Works - History. Retrieved February 20, 2017, from http://www.edisontechcenter.org/LED.html