greentechZONE Products for the week of February 12, 2007
LED Folio Says....
Solid-State Lighting Solutions Outlast, Outperform and Deliver Lower Cost of Ownership Than Fluorescent Lamps
Many thanks to Greg Hansuld, one of our sharp-eyed readers, who pointed out this interesting solid-state lighting company I'd somehow missed in my recent LED lighting update report. From the descriptions of LED Folio products on their web site and conversations with CTO Donald A Peifer, it looks like they've applied some innovative design techniques to deliver one of the first LED-based lighting systems that can go head-to-head with conventional fluorescent products. For this review I'll be breaking with the standard format which includes a press release with the manufacturer's claims, because LED Folio is just in the process of introducing its second-generation of LED lights (scheduled for production in June) and has not made any formal announcements to which I can yet refer.
 LED Folio offers several products with different form factors but for now we'll concentrate on their TiLux lighting panels which are form factor-compatible with standard drop ceiling panels and are intended as a direct (and much more attractive) replacement for the ubiquitous fluorescent fixtures that are standard equipment in most offices, commercial buildings, and even some homes (see Fig. 1).
One of the interesting things about this design is that it manages to deliver a very cost-effective lighting solution despite the fact that even the best commodity HBLED efficiencies are still somewhat lower than those of fluorescent tubes. This is because all of the LED Folio solid-state lighting products use a clever prismatic light guide that couples the entire output of its edge-mounted white LEDs to a front-end diffuser system (see Fig. 2). Together, they spread the light evenly across the panel's surface and make sure that almost every lumen (around 89%) they produce actually gets to where they're needed. This stands in sharp contrast to traditional fluorescent fixtures which can lose 45% - 55% of the bulb's output to internal reflection and absorption. Thanks to a more efficient optical design this allows a 65 W TiLux panel to deliver around 5 k lumens, or the equivalent of three modern 4 foot T5 fluorescent tubes.
 Their first generation products actually used low-cost blue LEDs and a photoluminescent film to shift their output spectrum to the white range, but the steadily-decreasing cost of white LEDs allowed the second-generation panels to eliminate the conversion film. Running white LEDs also gives you a choice of color temperature. For applications where the yellow-rich spectrum of a traditional incandescent lamp is desired, you can specify LEDs that offer a 3200°K color temperature. Selecting a 4500°K output gives you an indoor/outdoor effect that mimics a HID lamp while the cooler 5500°K output LEDs produce a daylight equivalent spectrum. LED Folio even offer an ultra-cool 6500°K option that's preferred by the Japanese market and a requirement for studio lighting for color television (Illuminant D).
As with all LEDs, TiLux panels run off dc power. This is supplied by a high-efficiency switching power supply that can be either integrated on the back of the panel or remotely located where mounting clearance is critical. The supply's integral PWM dimmer can be controlled either directly or remote control. Panels can be ganged together via a wired Ethernet daisy chain. An option for wireless remote control using a ZigBee RF interface supplied by AMX is expected to be added shortly after the product launch. An IR optical remote interface is also in development. Each unit is addressable via a unit code so that it can be addressed individually, or as part of a centrally-controlled area lighting control scheme. When LED Folio's 2nd-generation units hit the market they will also be equipped to work with occupancy sensors and ambient light sensors to make them even more useful in so-called smart building applications.
 While it will take another generation of solid-state technology to make LED Folio products significantly more power-efficient (in terms of absolute watts per lumen) than some of the better fluorescent products on the market, their current panels still offer significant economic and environmental benefits. The TiLux 70,000 hour life gives it a much lower cost of ownership (see Table 1) and eliminates the toxic waste problems that the mercury and phosphorous found in all fluorescent products raise (e.g., I have a big box of dead CFL bulbs sitting in the basement waiting for a safe place to return them for recycling or disposal).
My only concern about LED Folio products is that they really have to make sure nearly every photon coming out of their LEDs gets put to good use in order to make them as efficient as the extremely mature fluorescent technologies on the market today, and the optics they are using to do it are not yet proven. Everything I have heard from the company (including running their LEDs at a de-rated power level to ensure a longer service life) indicates that they've done their homework carefully, but only evaluating the products under real world conditions will prove that their product is a real contender to usher solid-state lighting into the mainstream for commercial and industrial applications.
If LED Folio can really walk the walk, I'd predict that the higher quality of the LED panel output will also help it gain acceptance in many residential and commercial applications where people still favor watt-hungry incandescent lamps to the harsh glare of a conventional fluorescent tube. In fact these are precisely the kind of products I would love to replace some of the compact fluorescent tubes that now light most of my home. Once they are in production, I'm hoping to coax LED Folio into sending me a couple of panels to road test in my office so I can give you a hands-on report on whether their performance matches the company's optimistic predictions.
The first generation of TiLux LED panels is available now, with the improved version scheduled for volume production in June 2007. Retail pricing for second-generation 2 x 2 foot TiLux panel will be around $300 each including power supply and dimmer circuitry.
More information on the TiLux ceiling-mounted LED panel is available here.
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