Intematix enables linear SSL products with remote phosphor optics

Dec. 9, 2013
ChromaLit Linear remote phosphor optics appear white in the off state and enable LED-based linear lighting systems that can produce 2000 lm per foot in CCTs ranging from 3000K to 5000K.

Intematix has introduced the ChromaLit Linear remote phosphor optic to enable LED-based lighting products including retrofit tubes for linear fluorescent replacement, cove lighting, under-cabinet fixtures, integral troffer luminaires, and high-bay lighting. The new optic appears near white in the off state, thereby mitigating the primary negative feature of the yellow-to-orange look of most remote phosphor optics for solid-state lighting (SSL) systems.

Remote phosphor SSL systems have been noted for the ability to offer a slight efficacy advantage compared to phosphor-converted white LEDs, and also for the ability to maintain color consistency over time. The fact that the phosphor is separated from the blue-pump LEDs means that heat from the LED doesn't cause any degradation in the phosphor that can result in color shift over time. The downside to remote phosphor has been the fact that many consumers prefer a white look when products are powered off, as well as the cost of the remote phosphor optics, although Intematix has maintained that cost is not an issue at the system level.

Intematix achieves the white off-state appearance by adding a reflective coating on top of the remote phosphor optic that preferentially reflects blue energy in the electromagnetic spectrum. We had a four-part series of articles on color science that concluded in February, which go into details of how humans perceive color and Intematix leveraged that science to create the new optic that has a slight off-white tint. But the color of the optic would not be noticeable in a fluorescent replacement or troffer application.

As for cost, Julian Carey, senior director of strategic marketing at Intematix, said that the combination of the optic and mid-power LEDs that would typically be used in the linear application could yield a system cost of $6 per linear foot, not including the driver electronics. Carey said that the technology yields a $2.40/klm system cost that is well ahead of projections by the US Department of Energy (DOE) on the cost of SSL systems.

As for efficacy, Intematix said that the optic enables product designs that deliver 163 lm/W at the system level. Carey said that the optic and coating actually optimize light extraction. Maximum flux output ranges from 1900 to 2050 lm/ft depending on CCT.

Moreover, the company said that the optic will deliver color consistency within a three-step MacAdam ellipse initially and over 50,000 hours of rated life. Carey said that Intematix has already tested the optic for 6,000 hours — the equivalent of what would be required for a phosphor-converted LED to achieve LM-80 certification. Carey said that so long as the temperature is kept to 90°C or below, Intematix is confident in the performance of the optics to 50,000 hours.

To showcase the technology, Intematix developed a 1-ft reference design. The unit is incredibly bright but also very uniform. Carey said that the demo delivers in the range of 1500 lm/ft. He added, "The high-bay guys are thrilled to have this kind of performance." In fact, he said they want to drive the LEDs even brighter. The standard product has a CRI of 80 and radiates a beam evenly over a 270° field.

Already there are products on the market from Tech Lighting and Horner Lighting that use the Intematix linear technology. Right now the optics are only available from Intematix directly. But as the company has done with other members of the ChromaLit family, it will offer the linear optics through distributors in the coming months.