Lighting : Lighting April 2015 - Vol 35 Issue 2
16 LIGHTING MAGAZINE | April/May 2015 April/May 2015 | LIGHTING MAGAZINE 17 FEATURE When the carbon-thread incandescent lamp was patented in 1879  it triggered a technological tidal wave that transformed the way humans slept, worked, and lived. From incandescent to neon and fluorescent, all the way through to LED, lighting technology has continued to evolve in ways that even the inventors, Edison and Swan, may not have been able to imagine. And it’s far from over – here are some of the top trends coming your way. OLEDS OLEDs, or organic LEDs, are a relatively new light source that has only started to take off in the last few years. This flat, cool semiconductor technology has already found a home in a range of applications such as smartphone screens, car headlights and LG’s recently released OLED televisions, revered for their exquisitely high definition pictures and bright saturated colours. OLEDs have also inspired promises of a future that includes OLED wallpaper that’s both a decorative feature and a functional illumination source, and smart phone screens that are so thin they can be bent and rolled. The possibilities of OLEDs seem limitless, but as a full-spectrum light source, their lifespan has long been hampered by a lack of efficiency in blue light, which makes up approximately 25 per cent of the content of white light. It’s a conundrum that researchers have struggled to solve. However, in 2014, a team led by Professor Stephen Forrest at the University of Michigan succeeded in developing a high efficiency phosphorescent LED (PHOLED) that extends the lifetime of blue OLEDs by a factor of 10 – four times as efficient as existing fluorescent OLEDs1. “Using phosphorescent blues, you can get well over 150 lumens per watt. That’s 10 times more than incandescent and it’s as good as any light source out there,” Forrest says. “As a matter of fact, if you put our devices into a white-emitting OLED for lighting, you would get probably operational lifetimes of close to 50,000 hours.” OLEDs have already captured a significant proportion of the display market as a result of their use in numerous Samsung mobile phones and tablets, and in LG’s highly acclaimed OLED TVs. There are also persistent rumours that new The future is here. The future is there. The future of lighting is everywhere. BY CLAIRE THOMPSON Encapsulating a blue PHOLED demonstrates its brightness. Encapsulation is also the critical technology providing OLEDs moisture and oxygen-free operating environment. Photograph by Joseph Xu.
Lighting February 2015 - Vol 35 Issue 1
Lighting June 2015 - Vol 35 Issue 3