At CEATEC JAPAN 2009, Mitsubishi Electric unveiled a 155” large-scale organic light emitting diode (OLED) display called Diamond Vision. Mitsubishi recently announced it will start selling the Diamond Vision OLED on September 21, 2010. This will be the first large-scale OLED display system available.
The 2009 demo system was built by tiling full-color passive matrix OLED displays, each 96 × 96 mm with 16 × 16 pixels. There were 720 tiles total—20 rows × 36 columns—resulting in a 1920 × 3456 mm display with 320 × 576 pixels. The commercial systems are assembled by connecting larger tiles, called standard modules (384 × 384 mm), with 128 × 128 pixels, weighing eight kilograms. The design allows the systems to be scalable, enabling them to form different sizes and shapes, for example, against rounded surfaces. The system depth is 99 mm, enabling it to be installed in limited spaces such as narrow paths and station concourses.
Figure 1: Mitsubishi PMOLED Display
*Frame and stand are optional
The OLED material used is small molecule, deposited by vacuum evaporation, jointly developed with Tohoku Pioneer Corporation (Mitsubishi Chemical is also working with Pioneer to develop OLED lighting). Mitsubishi Electric indicated that it is possible to manufacture displays with resolutions that are comparable to LED displays, but at a lower cost. Pricing has not yet been announced.
One of the most interesting aspects of this display is the use of passive matrix OLED technology. PMOLED display revenues peaked in 2006, and have been falling since. This is a result of active matrix taking over the OLED market, driven by adoption in smart phones. PMOLED has been limited by its inability to address large numbers of pixels in a single display, which disqualifies it from applications requiring full color and high resolution.
But the very low resolution of this display (the pixel pitch is 3 mm, about 50 times the pixel pitch in smart phone displays), along with the fact that each display tile has only 16,000 pixels (compared to 300,000 in a VGA smart phone display), means that PMOLED is a viable option. Because of the low resolution and small size of each tile, they can likely be produced at high yields using existing equipment.
With PMOLED shipments declining, and mostly being used for very small secondary displays on handsets, there is an excess of manufacturing capacity. It will be interesting to see if this tiling approach is successful in boosting PMOLED display sales in the future.