Screen resolution and pixel density have been some of the primary weapons used on the battleground for mobile device superiority in today’s world market. Apple drew first blood with a 960×640 pixels resolution with the “Retina” 326 ppi pixel density debuted with the iPhone 4, only to later be bested by the Samsung Galaxy Nexus (1280×720 pixels and 316 ppi) and the recently announced HTC One X.
In the high-profile competition between smartphone makers, microdisplay technology (used in the electronic view finders found on some cameras and medical-devices) has largely been ignored, even if it’s millions of pixels ahead anything available on a smartphone at this moment.
And the ante has gone even upper with the announcement of a low-power (0.2 W) OLED-on-silicon microdisplay manufactured by French company MicroOLED that packs 5.4 million dots (a dot is a subpixel) into a 0.61-inch screen. This is the equivalent of a 1400×1044 pixels resolution (for a full-color display), with an incredible pixel density of 2916 ppi. How’s that for a high-res display? And the monochrome versions go even higher in terms of pixel density, achieving 2500×2000 dots over the same area.
So, what is the technology behind MicroOLED’s breakthrough? Similar to the liquid-crystal-on-silicon(LCOS) microdisplays used by Sony in their NEX series, the OLED-on-silicon displays are fabricated on a silicon IC backplane that contains pixel switches made of single crystal silicon. A continuous OLED layer is deposited on the silicon backplane, with the color being provided by a matrix color filter, as opposed to the more conventional RGB patterning on the front plane.
Applications of microdisplays are primarily in the medical field (for high quality video goggles for HD endoscopies), augmented reality glasses for people with low vision, electronic viewfinders for microscopes, and also for military applications.
As the technology improves, we can also expect more consumer friendly applications (Google Glasses, maybe?) and it’s reasonable to believe that this product will eventually replace traditional optical view finders in the near future.
Will this high resolution/high pixel density display end up on our smart phones or tablets? It seems highly unlikely, given the current mobile technologies and issues such as cost of production and manufacture capability. But, with the announcement of MicroOLED’s microdisplay, we certainly get a glimpse of the direction in which mobile device screen technology is headed.