You go to a trade show and look for the things you know you should learn more about, but it’s often what you don’t expect to find that’s the most striking. Last week at FPD International in Yokohama I stumbled upon a very-low-power LCD technology in the Sharp booth: the memory LCD.

Ken Werner
Senior Analyst and Editor

There wasn’t a lot of information — at least not in English — but apparently each pixel contains non-volatile memory that keeps the pixel appropriately switched with little or no power being consumed except when the display is re-addressed. The displays came in various formats and sizes, but particularly impressive was a 6.1-inch (15-cm), reflective (of course) 8-color display with 324×244 pixels, which had "no stand-by power consumption" according to Sharp’s data panel. A bunch of similar but smaller color displays (see photo) had a similar look.

These panels had all of the essential characteristics of ePaper. They were reflective and had a paper-like appearance. Although they are not bi-stable, the memory function gets around that and the displays do not draw power when in stand-by. In addition, the colors are agreeably saturated, which is still something of an issue for electrophoretic color.
Of course, there are still questions, among them, what is the reflectivity (and therefore "brightness") of these panels relative to electrophoretics, and even more important, what is the relative cost?

Also on display in the Sharp booth were 1.4-inch, 96×96-pixel reflective and transmissive pixel-memory LCDs, both 8-color and monochrome. These displays had a claimed power consumption of 10µW (that’s microwatts).

So, are the purveyors of "real" ePaper — that is, electrophoretic, cholesteric-LCD, liquid-drop, optical interference, and other bi-stable (or nearly bi-stable) - displays worried? We’ll let you know in the next chapter.