They light up the clock on your DVD player, the channel numbers on your radio and the displays of the myriad electronic devices all around you.
Ditto, more and more these days, your car lights and the traffic lights that tell you to stop, go and use a little caution, buddy, not to mention your laptop screen, Christmas tree and possibly in the near future your living room.
And while it may be overkill when people describe a lot of things as "ubiquitous," light-emitting diodes aren't one of them.
So it's no surprise to find Nick Holonyak, the inventor of the first practical light-emitting diode in the visible spectrum, on a list of inductees to the National Inventors Hall of Fame, whose first inductee when it opened in 1973 was Thomas Edison.
Last year's inductees included the late Paul Lauterbur, the UI professor and Nobel Prize winner who helped lead the development of magnetic resonance imaging, or MRI. Holonyak's mentor at the UI, the late John Bardeen, a two-time Nobel winner and one of the inventors of the transistor, was inducted in 1974.
The 2008 class was announced Thursday in Washington, D.C. The U.S. Patent and Trademark Office and the National Council of Intellectual Property Law Associations created the hall as the "premier not-for-profit organization in America dedicated to recognizing, honoring and encouraging invention and creativity."
Its permanent home is in Akron, Ohio, where this year's induction ceremony will be on May 2-3.
Other inductees include the late Robert Adler, a friend of Holonyak's who invented the television remote control; and inventors of such things as wrinkle-free cotton, Styrofoam, silicon solar power cells and hip replacement surgery.
Holonyak may be one of the most recognized figures, in terms of awards, on campus. The UI electrical and computer engineering and physics professor already has received the Institute of Electrical and Electronics Engineers Medal of Honor, the highest award by the leading professional organization in his field, and numerous other awards, international as well as national, including the Japan Prize. He's a member of the National Academy of Engineering and of the National Academy of Sciences and is a foreign member of the Russian Academy of Sciences, among other things.
But Holonyak on Thursday afternoon acknowledged that the Inventors Hall is "a little bit different," more about "payoff stuff" with broad practical applications and impact than scientific and engineering research.
UI Chancellor Richard Herman even used the U word in announcing the honor.
"Nick Holonyak's inventions, like all great works of scientific inspiration, have changed our world," Herman said in a press release. "Think, for a moment, of the impact of LEDs. Today, they are ubiquitous, in games, household products, medical equipment, automobiles and countless other applications."
For his part, Holonyak said he appreciated the honor – then launched into the topic of the laser-emitting transistor he and UI colleague Milton Feng and their students are developing now. Holonyak thinks that invention could change electronics technology over the next 50 years, and maybe land Feng, grad student Gabriel Walter and some others in the Inventors Hall.
"I'm more excited about that," Holonyak said.