Wacom builds the touch screen technology used on a number of eBook Readers.
Wacom has two technology offerings. They can even work together on the same product. The newest is a capacitance finger input that shares technology with the resonance electromagnetic pen product.
 EMR® (Electro-Magnetic Resonance) Technology
The technology differs from other devices in that the sensor is below the screen and does not change the contrast or shininess of the screen in any way. However, you must use the supplied stylus and when the touch screen is on it pulls some power from the battery.
Wacom tablets use a patented electromagnetic resonance technology. Since the tablet provides power to the pen through resonant coupling, no batteries or cord is required for the pointing device. As a result, there are no batteries inside the pen (or the accompanying puck). This allows for more slender pens, and gives the pen-and-tablet combination a long and essentially maintenance free lifespan.
Wacom tablets are generally more accurate than touch screen based devices when it comes to writing on them with a pen. Also, since the tablet only reacts to the pen, one can rest one's palm on the device while writing, like one would on real paper, providing a much more natural and comfortable experience.
 RRFCTM Touch Technology
RRFCTM (Reversing Ramped Field Capacitive) Touch technology leverages the EMR technology to allow finger touching. It can be used separately or the two technologies can be used in a single product.
Wacom RRFC touch uses a similar glass sensor (touchscreen) construction to existing capacitive touch solutions but detects and measures the touch using a completely new technique based on mostly digital circuitry and proven Wacom EMR pen ASIC components. Touch location is detected by measuring the very small current changes that result from the close proximity of a finger to four ramped electro-static fields generated over the surface of the sensor (as opposed to a single flat electro-static field used by legacy capacitive solutions). The specification for accuracy in Wacom RRFC touch will be ± 2mm even at the edge of the glass.