This post was written by Keith Dawson for UBM Tech’s community Web site All LED Lighting, sponsored by Philips Lumileds. It is archived here because the All LED Lighting site has gone dark. This material is Copyright 2013-2015 by UBM Americas.


Monday Roundup: Still Bright

This week: the world's largest OLED TFT display, putting tungsten halogen in its place, and a discontinuous improvement in the rate of growth of light output due to GaN-on-GaN.

Soraa graphs its claimed jump in light output
The company's CTO has been writing a series of blog posts lately intended to bust the "Top Ten Myths of LEDs." It is rather difficult to find working links to all of them on Soraa's site -- its naming leaves something to be desired -- so I have collected the links here.

  1. (not published yet)
  2. LEDs will increase consumption of rare materials
  3. LEDs have low light output
  4. LED retrofit lamps don't work
  5. LEDs color-shift with time
  6. LEDs can't run hot
  7. LEDs have high glare
  8. LEDs are best left to China
  9. LEDs are expensive
  10. LEDs are dangerous

They are all worth reading, but I want to highlight one eye-catching graph from the LEDs have low light output post. It represents the discontinuous jump that Soraa has claimed to have achieved in LED light output as a result of their proprietary GaN-on-GaN process. If the big players are not talking to Soraa about licensing GaN-on-GaN, I wonder why not.

Still bright after 25,000 hours
The US Department of Energy's Solid State Lighting Program has updated its lumen maintenance testing report for the L-Prize winner, Philips's 60-Watt incandescent replacement bulb, which took the prize in August 2011. (A Philips subsidiary, Lumileds, sponsors this site.) Based on 200 bulbs operating continuously at 45°C in a PNNL test apparatus, the DOE reports that the bulbs' light output shows no diminution after 25,000 hours. The L-Prize contest rules only required that the winning bulb decline to no less than 70 percent of its initial output after that length of time. Chromaticity shifted by 0.002; the rules allowed 0.004. The Designing With LEDs blog notes the irony that Philips has now discontinued the line in which the L-Prize bulb was sold, opting to consolidate design around that of its popular Hue bulb.

The world's largest OLED TFT display
A year ago, Arizona State University's Flexible Display Center (FDC) set the size record for flexible OLED TFT displays, producing one measuring 7.4 inches (18.8 cm) diagonally. The same group just nearly doubled its own record, announcing a 14.7-inch (37.3 cm) display. The FDC is a partnership among government, industry, and academia, and is funded by the US Army.

Tungsten halogen isn't all that carries an amusing rant, from lighting designer James Bedell, on those who refuse to consider using LEDs in their projects because tungsten halogens are perfect. Bedell explains exactly why they are not -- beyond their energy-inefficiency -- and concludes, "It's time to get away from this false choice that we can only have beautiful light or sustainable light. The real world demands that we create both."

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— Keith Dawson Circle me on Google+ Follow me on Twitter Visit my LinkedIn page, Editor-in-Chief, All LED Lighting