Isamu Akasaki of Meijo University and Nagoya University, Hiroshi Amano or Nagoya University and Shuji Nakamura of the University of California, Santa Barbara are the recipients of the 2014 Nobel Prize in Physics for inventing the blue light-emitting diode (LED) in the early 1990s. Blue LEDs combined with green and red LEDs produce white light, thus enabling the production of LED light bulbs. LED bulbs are much longer-lasting, up to one hundred times, and more energy-efficient than traditional incandescent bulbs.

Dr. Nakamura filed his first patent application for a “blue color light-emitting diode” in April 1991 and was granted a patent in 1998 (JP2791448 B2). Akasaki and Amano, who began collaborating in the late 1980s, filed their first joint patent application in 1989 for a method of manufacturing a gallium nitride semiconductor LED. Their patent issued in 1994 (JPH069257 B2). Collectively, Akasaki, Nakamura and Amano are the named inventors on dozens of patent applications and authors of hundreds of journal articles.

LEDs are classified in H01L 33/00. According to Espacenet, more than 96,000 patent documents are classified under this code.

The incandescent bulb was developed in the 1870s and perfected by Thomas Edison in 1879 (US 223 898), launching the electrification of the world. For over a century incandescent lighting was the dominant form of lighting in most countries. Today, incandescent bulbs have been replaced in large part by LED bulbs.