OLED is a unique lighting technology - it enables flat, diffused planar lighting panels. These panels are different to the point (or line) sources we're used to - incandescent, fluorescent, CFLs and LEDs. But you can also use LEDs to build planar lighting panels. Several companies are offering such solutions called edge-lit panels.

Israel's OREE developed proprietary technology that enables them to offer panels which are so thin that they are quite similar to OLED panels in form (almost... more on this below), yet are efficient, very bright and a lot cheaper than current OLEDs. They were kind enough to invite me to their offices for a visit and also sent me a couple of samples for a review.

OREE LightCell Duo and electronics photo

So let's understand OREE's technology first. OREE's lighting panels (they brand them as LightCells) are made from red and blue inorganic-LEDs, a light guide which basically spreads the LED point lighting source into a diffused panel, and a planar remote phosphor coating that converts the blue and red light into white.

OREE LED Lightcell structure

OREE is not a LED maker, they are buying the LED chips and components from well known suppliers. The company real IP is the planar remote phosphor and the packaging itself - embedding the light sources and the design of the light guide. This technology allows them to achieve efficient panels that are very thin. Basically they claim their Lightcells look like OLEDs but feature the efficiency, brightness, lifetime and cost of LED panels. The company produces the entire planar-LED module and supplies these modules to luminarie and fixture makers.



OREE's basic LightCell is a square, 7 x 7 cm in size (active-area, the actual panel is a larger as it has a bezel and the base where the LEDs and electronics are housed). They call this the LightCell Solo, and it's bright (350 lumens), efficient (around 100 lm/W at the module level) and long lasting (about 50,000 hours). The CRI is over 90 and it comes in three different color temperatures (2700K, 3000K and 4000K). OREE also offers the LightCell Duo which is double the size (14x7 cm, 700 lumens) and the Quad (28x7 cm, 1400 lumens). All these modules are 4.7 mm thick.

OREE Lightcells image

The first thing I noticed about those LightCells when turned off is that they have a quite ugly bright yellow color. This is the phosphor material that converts the red and blue LED emitted light to white. When you turn them on it emits nice white light of course. The company actually developed another kind of panel which uses a different kind of phosphor which is ivory-white in color when off. This looks much better. The company already launched these Ivory LightCells - they cost the same as the regular LightCells, but are less efficient (by about 10%).

When you turn the LightCells on, they are very bright. I am used to OLED panels which emit very few lumens - the brightest OLEDs I have at home are less than 100 lumens bright, and OREE's LighteCell Solo is 350 lumens. The Duo is extremely bright - 700 lumens and it's too bright to look at up close. The Quad offers 1,400 lumens - nearly equal to a 2-feet fluorescent tube. Of course OLEDs are catching up and Philips' brightest panel, the GL350 currently offers 200 lumens and next year they aim to increase it to around 300 lumens.

Another thing you see when you turn them on is a purple glow - coming from the back where the LighCell is connected to the power. The purple glow results from the red and blue LEDs. OREE says that once you enclose these modules in a fixture or a luminaire this glow will usually not be seen. I'll have to take their word for it.

OREE LED light photoOREE LED and Philips OLED light photo

When you compare OREE's LightCells to OLEDs, the first thing you notice is that they are quite thick. While 4.7 mm is not a lot, OLED panels are a lot thinner. LG Chem's for example currently makes rigid panels that are 1 to 2 mm thick. LG's flexible OLED panels (which will hopefully be in production by the end of the year) will be only 0.33 mm thick and the company is planning bendable OLEDs in 2015 which will be thinner still. Of course these are "bare" OLED panels and not modules but still the thickness difference is considerable. So do not expect OREE's LightCells to be used in radically thin designs.

OREE Duo & Lumiblade OLED photoOREE Duo & Lumiblade OLED closeup photo

OLEDs also do not need the phosphor materials. So while OREE's LightCells are either yellow or ivory in color, turned-off OLEDs can look like a mirror, or even be transparent. I think this is a major plus for OLEDs especially for the premium lighting market.

Of course OREE's major competitive advantage over OLEDs is the price. OLED panels today, while still low in brightness, lifetime and efficiency cost $100 or more for a small panel. OREE, on the other hand, are offering a complete lighting module (the LightCell Solo) that features 100 lm/W, 350 lumens and a long lifetime for less than $10. The larger versions are even cheaper (per lumen). This is competitive with regular LED lighting and the company is ready to mass produce such panels on demand as they are made from readily available components.

I think that the key question is whether there will be a large enough demand for planar lighting? OLED lighting is currently used only in premium luminaries and large, expensive, installations. OREE's offer could mean much cheaper solutions and I guess the company's challenge is now to actually create this new market, and reach lumiaire and fixture makers that will use their panels in real mass market lamps or installations.

Planar LED lamp design

OREE is obviously aware of this and are currently approaching the functional, task decorative and orientation lighting applications where diffuse, high CRI and flat light sources are an advantage. So hopefully we'll begin to see their LightCells in places such as hospitals, retail shops and offices. The company's own conference room (where we had out meeting) is being exclusively lit with their planar lighting sources and even though they did it themselves it looks quite good. Apparently OREE is involved with several projects around the world. The first project we're aware of was Cnlight's desk-lamp that was released back in 2011.

Regarding future developments, the company already released the ivory-colored panels, which are now available. OREE is already working on their next-gen lighting devices. I cannot disclose a lot of information, but the company hopes to double the lumens-per-dollar ratio compared to the current generation panels. They are also planning to release these new devices as a replacement module for fluorescent modules for offices. Those panels will look a lot better than fluorescent lighting, be more efficient, will provide better lighting quality and be cost competitive. Hopefully those next-gen lighting panels will be ready by the end of 2014. Finally, OREE says that their technology allows them to produce flexible (conformable) and transparent panels (where part of the panel is transparent, not all of it). Hopefully they will be able to bring such designs to the market in the future.

I'd like to thank the guys over at OREE for the visit and the samples and the information. It'll be very interesting to see whether lighting makers adopt OREE Lightcells and I hope they will at least provide a technology and design bridge for OLED-based panels in the future. You can find more information about their technology and products here.

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