I’m not sure I would say these three men “perfected” LEDs, but we certainly wouldn’t be where we are today without Isamu Akasaki, Hiroshi Amano and Shuji Nakamura.
These scientists, who invented blue LEDs back in the early 1990s, were awarded the 2014 Nobel Prize in Physics this week. Their work allowed other brilliant physicists, electrical engineers, chemical engineers and optical designers to take their blue LEDs and transform them into the powerful white LEDs that we use in many commercial products today.
For those that don’t know, almost every LED that currently goes into LED fixtures (except for those sneaky people at Cree) is a blue LED that has some orangish/yellow phosphor placed over the top of it to convert some of those blue light photons into red and green light photons.
I’m not going to claim to know why blue + phosphor works great, but green or red + phosphor doesn’t work. People far smarter than me explain that it was necessary—so I believe them.
So, where are we today because of Akasaki, Amano and Nakamura? When they first invented those blue LEDs in the early 90s they were probably ecstatic to be able to coax just one lumen per watt out of the blue LED. When I first started designing with LEDs, which was (gulp) almost 10 years ago, we were thrilled to be getting 25-30 lumens per watt out of the “white-ish” Lumiled LEDs that we used in jewelry case applications.
Oh, and just a single LED cost around $3. I always thought our shipment of LEDs should arrive on a Brinks armored truck rather than a FedEx truck. That was the best anyone could do back in 2005. So LEDs were primarily used in niche markets and were still just a buzzword in the lighting world. Fluorescent was still king.
What I think precipitated this Nobel Prize 20-some years after the invention was the general thought in the lighting world that fluorescent has lost its crown. Cree just announced that they have a commercially available 2x4 recessed fixture that is at 150lm/W. Late last year Philips publicized their goal to have a 200lm/W T8 LED tube available in 2015 and they displayed the prototype at Lightfair this year.
Once LEDs started naming their products after the fluorescent versions they are aiming to make obsolete, I think the time came to officially crown a new king. So, here’s to Isamu Akasaki, Hiroshi Amano and Shuji Nakamura. The product that you invented before young Tony Johnson ever knew what the heck a lumen was, has turned the lighting world on its head and made my job ever-changing and consistently exciting.
Tony Johnson is Energy Management Collaborative's Technology Manager. In this role he combines his background in lighting & controls design and solid state light fixture design with his expertise in energy savings to evaluate emerging technologies for EMC customers.