LEDs and Beyond: Seeking a Perfect but Efficient White Light
Frank Jones, a lighting distributor for Tri-State Supply, has become something of an expert on light emitting diodes, better known as LEDs. He says that's because each of his customers wants something different.
"I have one individual customer that has an administration building. The hallway wants one color. The conference room, they want nice, warm 2700K, and then Gary the accountant wants nice, white bright 5000," Jones says.
First, let’s clarify those numbers. They describe the LEDs’ color, which is measured in something called Kelvin, or K. A cool blue is 5000, while 2700 indicates a warm yellow. Most people want a classic white, so that their rooms look the same as what they’re used to with incandescent bulbs.
Manufacturers currently make white by covering a blue LED with a yellow chemical compound called a phosphor. But layering color this way steals about 15 percent of the LEDs’ efficiency.