There are 2,073,600 pixels in a 1920x1080 HDTV. That’s two million! A rare few monitors exceed that resolution--the 2560x1440 Apple iMac screen ups the pixel count by a million and a half to 3,686,400 pixels. Yet even the Apple Cinema Display can't hold a candle to a prototype 3DTV Samsung showed off last week, which manages to pack eight million pixels into a 70” screen. Impressive as lofty numbers can be, the technology behind Samsung’s TV is more interesting than a raw pixel count.
To cram eight billion pixels into a 70” screen, Samsung had to shrink each pixel. Shrinking each pixel means shrinking the transistors that control them, and traditional silicon transistors couldn’t cut it at that lowered size. So Samsung turned to an emerging technology called metal oxide semiconductors.
EDIT: While Technology Review claims this is an 8 billion pixel display, a 4Kx2K display would only contain 8-9 million pixels. We've edited for clarification and contacted Samsung to find out more about the display.
You may have heard of metal oxide semiconductors before--they were paired with flexible OLEDs in the army wristband we wrote about last year. OLEDs require too much current for the amorphous silicon used in thin film transistors, so manufacturers use polysilicon instead. Despite being an emerging transistor technology, metal oxide is cheaper, which should make OLEDs more practical.
Samsung turned to metal oxide transistors because they conduct electrons more quickly than amorphous silicon. As the pixels and transistor arrays shrink, amorphous silicon just can’t get the job done fast enough. Metal oxide semiconductors can, and they’re relatively cheap to manufacture. Even better: they’re transparent. So why haven’t we been using them all along? Finding the right mixture of metals hasn’t been easy--the current pack leader is a combination of indium, gallium, and zinc.
Sharp, ever on the cutting edge of display tech, has already announced that it plans to put metal oxide to work in displays by the end of the year. We don’t expect 1440p TVs flooding the market, but Sharp may well use metal oxide transistors to produce sharper tablet and phone displays with denser pixel counts. With this technology at work, a 2048x1536 iPad display doesn’t sound so crazy.