Partners Cambrios Technologies and Novaled have claimed a breakthrough it creating OLED tiles that have no visible metal grid to evenly spread current through the panel. The duo have used Cambrios' ClearOhm transparent electrodes to produce 10×10-cm tiles with uniform light distribution suitable for mainstream solid-state lighting (SSL) applications.
Novaled is an OLED specialist and Cambrios is focused on nanotechnology that enables transparent and flexible conductors. The two asserted that presently available OLED tiles in the 100-cm2 range use a visible metal grid to evenly distribute current, thereby ensuring uniform light distribution across the panel.
We covered OLED technology in detail, including the current spreading issue, in a feature article in our Illumination in Focus publication last year. And the most widely deployed OLED tiles to date made by LG Chem do in fact use a metal grid, although Acuity Brands is selling luminaires that use the tiles and insists that the grid is not visible if you are more than a few feet from the fixtures. Philips, meanwhile, has its own undisclosed technical approach to building OLED tiles with no visible grid.
Cambrios says that its ClearOhm coatings have as much as 75% lower resistance than the indium tin oxide transparent electrodes used by some manufacturers. The ClearOhm sheet resistance is as low as 5 Ohms per square.
"We chose to partner with Cambrios because of their coating materials excellent performance. Novaled’s materials and technology in combination with Cambrios' ClearOhm coating materials as a transparent electrode led to high performance hybrid OLEDs," said Sven Murano, Novaled’s vice president of product management. "With this approach manufacturers can produce high-performance, long lifetime OLED lighting tiles in high volumes at affordable costs."
Cambrios and Novaled did not say when the OLED technology would be commercially available. Cambrios has said that it has produced 5×5-cm tiles with efficacy greater than 40 lm/W – and that's better than some tiles on the market.