EdisonReport sponsored the 15th Annual Phosphor Global Summit earlier this week in San Diego. If you are a phosphor engineer, this conference was a dream come true as the technical information was deep and detailed, meaning some subjects were clearly over my head. But there were a few take aways that your humble editor found fascinating.
William Beers, DFSS Black Belt, Senior Systems Engineer for Current, powered by GE, spoke about TriGain™ phosphor which is revolutionary in that it allows for a 90 CRI, 168 LPW, and R9>90. From what I learned in the presentation, and in talking with others, it appears that GE leads in this technology. GE launched TriGain in a few products at the 2016 LIGHTFAIR and we expect to see more in Philadelphia later this year. Today, 14 luminaires have this technology.
Current has licensed TriGain for the display market to about 17 companies, and has licensed it for general lighting to zero companies. GE is not known for display lighting, so licensing in that channel makes perfect sense. But in general lighting, TriGain is a true spec-lock, so the strategy to not license is smart.
Mr. Beers flashed a slide listing patents and I counted 16 patents either current or pending. In talking to a few members of the audience, we learned that the strength of the patents is really in the application, so others may be able to build the phosphor, but the OEM would be in violation once the phosphor was applied.
Dr. Aleksander Zych, Research Scientist Lighting Lab Manager at EMD Performance (known as Merck in the rest of the world) spoke about turning away from the blue LED to violet, which brings great benefits. EMD Performance is able to build phosphors for both the sleep cycle (encourage relaxation) and the awake cycle (encourages stimulation and productivity.) He discussed one product having 4000K and a CRI of 90, allowing for sun-like spectrum, that could be used for both types of cycles.
Dr. Sadakazu Wakui, Engineer of LED Back-end Material Engineering, Nichia spoke on the World’s first Ultra-High CRI LED, with all R indices >90. Nichia is vertically integrated in that they build the chip, the phosphor and the package. Dr. Wakui explained that today >80 CRI is now mainstream and it is going to 90 and soon 95. He showed a slide featuring 100 CRI. This was the first session where I have heard anyone discuss CRI up to 100.
In 2016, Nichia released a product with a CRI >95.
According to Dr. Wakui, the old approach to improving CRI was to add green and red phosphor, and then enhance the red component. Current technology to improve CRI uses a UV chip and RBG phosphor at 405 nanomenters, which has a chip with four phosphors with 54% efficacy. Then they take a blue chip and add two phosphors and have 100% efficacy.
The new Nichia way is to select a 420 nanometer chip which has no emitting UV radiation and no overlapping spectral distribution of the R12. He spoke of two phosphors as candidates: Apatite and BAM. Apatite phosphor has good excitation and they fire the apatite type blue phosphor under a reduction atmosphere to crystallize the structure.
While I do think we are a long time from 100 CRI, I am excited about seeing 90 CRI becoming mainstream in the next few years.