Photo courtesy GE
On October 9, 1962, Dr. Nick Holonyak, Jr., invented the first practical visible-spectrum light-emitting diode (LED). He was 33 at the time. Today, with the technology well-established in signmaking and many other industries, he reflects upon the discovery.
When Holonyak joined General Electric’s (GE’s) team of researchers in 1957, they were working with other scientists and engineers on semiconductor applications and building the forerunners of modern diodes called thyristors and rectifiers.
“I was doing exploratory work with a small group,” he says.
By the summer of 1962, various research labs were racing to invent the first semiconductor laser. At GE, Dr. Robert N. Hall was developing one in the infrared (IR) portion of the light spectrum with gallium arsenide (GaAs), using polishing to form laser mirrors. Holonyak, on the other hand, decided to use gallium arsenide phosphide (GaAsP) to facilitate visible light, with mirrors formed through cleaving.
“If they can make a laser, I can make a better laser than any of them, because I’ve made this alloy that is visible,” he says, remembering the competitive forces that led to his moment of discovery. “I’m going to be able to see what’s going on and they’re stuck in the IR.”
When Holonyak became the first person to operate a visible semiconductor alloy laser on October 9, 1962, his colleagues called the resulting LED “the magic one,” because its red light was indeed visible to the human eye. He knew it was a significant moment.
“I’m just at the front end, but the result is powerful,” he remembers. “There’s no ambiguity; this has a life way beyond what we’re seeing. It became the red LED everybody would see in elevator panels and everywhere else.”
LEDs are illuminated by the movement of electrons through a semiconductor material. Holonyak calls them “the ultimate lamps” because “the current itself is the light,” leading to higher energy efficiency and lower losses of light.
With subsequent developments, LEDs became available in multiple colours and were used in an ever-broader array of applications. They revolutionized lighting in the sign industry, succeeding neon, fluorescent and even high-intensity discharge (HID) lamps in many types of commercial signs. And in the digital signage arena, they enabled the development of immense full-motion video boards.
Today, LEDs are reaching mainstream lighting applications in parking lots, roadways, retail chains and even residences.
“You see lights everywhere and they can all be redone and made better,” Holonyak says, issuing a call to the industry for further research and development (R&D). “This isn’t the end. Learn more, do more, build more, reveal more.”
