news digest ♦ LEDs
The real magic of quantum dots is in the ability to tune the colour output of the dots, by carefully controlling the size of the crystals as they are synthesised so that their spectral peak output can be controlled within 2nm to nearly any visible wavelength.
A quantum dot, which is 10,000 times narrower than a human hair, can be tuned to emit light at very precise wavelengths. This means display makers can create a highly-optimised backlight that only produces the exact wavelengths of red, green and blue light needed by an LCD for optimal colour and energy performance.
Trillions of these quantum dots protected by barrier film fit inside an LCD backlight unit. The new film replaces one already found inside LCD backlights, which means the manufacturing process requires no new equipment or process changes for the LCD manufacturer.
“Improving colour performance for LCDs with simple, drop-in manufacturing solutions will create a stunning new visual experience for consumers,” comments Jason Hartlove, president and CEO, Nanosys, Inc.
“Working together with 3M and utilising their outstanding design and supply chain capabilities will allow our quantum dot technology to be widely deployed across all product segments, ensuring availability to all customers,” he adds.
Soraa to ENERGY STAR: Light quality vital for LED adoption
The GaN on GaN LED specialist has asked the EPA not to repeat mistakes made on compact fluorescent lamps (CFLs)
To ensure the long-term success and widespread market adoption of LED lamps, Soraa last week urged the U.S. Environmental Protection Agency’s (EPA) ENERGY STAR program to address light quality.
In particular, the firm is concerned about colour rendering, in its new lamp specification.
Support for higher colour rendering has been expressed by the California Lighting Technology Centre; Shuji Nakamura and Steven DenBaars; the International Association of Lighting Designers (IALD); Northeast Utilities Companies (NSTAR); and lighting designer Chip Israel; who all filed formal comments on EPA’s Draft 3 product specification for LED lamps.
“Poor light quality ruined many consumers’ confidence 76
www.compoundsemiconductor.net June 2013
in compact fluorescents,” says Mike Krames, CTO of Soraa. “The ENERGY STAR qualification must be associated with LED lamps that provide a better quality of light; otherwise, the program will start to lack credibility with end-users and the low adoption rate history of CFLs will be repeated by LED lamps.”
In comments filed with the EPA on May 17th, Soraa told EPA that while ENERGY STAR is not a mandatory standard; the agency must recognise that it has become a de facto standard for utility rebate dollars critical to lowering the initial cost of LED products.
In the absence of a second high colour rendering index (CRI) tier, it is likely that, similar to the historical situation with CFLs, the vast majority of lamp products will be engineered to perform close to the lower boundaries of quality requirements as set in the ENERGY STAR lamp specification for cost reasons, as shown in the figure below.
Light output vs. colour rendering index (CRI) for both PAR Lamps (left) and CFL (right) from the ENERGY STARQualified Lighting Product List (QLPL), compared to conventional light sources (red ovals). The current standards drive the industry to predominantly produce modest colour quality lamps, which do not address the colour quality barrier to adoption
Left unaddressed, this lack of high colour quality lighting products will lead to a stalling in consumer adoption of energy efficient lighting technology, similar to what has been observed to date with CFLs.
“To persuade consumers to purchase LEDs instead of incandescent lamps, LED lamps must be seen as high- quality products worth the initial higher price differential. Therefore, LED lamps must closely replicate the colour rendering of the incandescent and halogen lamps that they replace,” explains Ravi Parikh, Energy Services Specialist at Burlington Electric in Vermont.
“The Soraa VIVID is such a product, providing superior colour quality while improving energy efficiency. As a utility, we are always willing to consider higher incentives for projects utilising lamps such as Soraa’s. We want to ensure customer satisfaction by reduced energy bills and
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