A light-emitting diode, also known as LED, is a semiconductor light source. Currently the LED lamp is popular due its efficiency and brightness. Many believe that LED is a “new technology”; however, the LED as we know it has been around for over 50 years. The recent development of white LEDs is what has brought it into the public eyes as a replacement for other white light sources.
1907– H.J. Round reports light emission from a crystal detector.
1927– Oleg Losev notes that silicon carbide crystal diodes used in radios glowed when excited by an electrical current.
1939– Zoltan Bay and Gyorgy Szigeti patent a silicon carbide electroluminescent lighting device, considered to the predecessor to the modern-day LED.
1951– William Shockley, co-inventor of the transistor, files a patent for an infrared LED.
1961-Bob Biard and Gary Pittman developed the infrared LED at Texas Instrument. This was the first modern LED.
1962– Nick Holonyak creates the first practical visible-spectrum LED at Ge’s advanced Semiconductor Laboratory in New York.
1964– IBM uses LEDs on circuit boards in an early mainframe computer.
1968- Hewlett Packard integrates LEDs into early hand-held calculators.
1972– M. George Craford creates the first yellow LED.
1979- Shuji Nakamura develops the world’s first blue LED.
1995– The first LED with light from luminescence conversation is presented and is launched on the market two years later.
1999-Philips Lumileds introduced power LEDs capable of continuous use at one watt.
2002-Lumileds made five-watt LEDs available with a luminous efficacy of 18-22 lumens per watt.
2006- Nakamura wins the Millinnium Technology Prize for development of a white LED.
2007– Italian village, Torraca was the first place to convert its entire illumination system to LEDs.
2008- Audi is the first car to use fully LED headlamps.
2011– LEDs have become more efficient, so that a 6-watt LED can easily achieve the same results as a standard 40-watt incandescent bulb.