# Explanation of touchpoint density in touchscreens

I'm looking at touchscreen supplier specs such as this one.

What does the specification "touchpoint density" expressed as touches/sq.cm sq.in or mean? The value given is "> 100,000 touches/in^2". Does this mean it can differentiate between pinpoint touches at 100,000 points at every square inch?

## 1 Answer

In 1 square inch of touchscreen area, there are more than 100,000 distinguishable points. It doesn't mean it can distinguish between a touch at (0,0) and (1,0), but that the touchscreen controller could return 100,000 different points.

• So, to clarify, since sqrt(100000) is about 316, the controller can return any coordinates from (0,0) to (316,316) in one square inch? – Jay Feb 29 '12 at 15:48
• Be careful in general this resolution is a math exercise. The sensing methodology gives four signals which are used to calculate the center of touch which is reported. The number of points reported is more a function of how many "decimals" I include in the calculation. To borrow an ADC parallel, beware the ENOB of reported position. – naven87 Nov 22 '12 at 7:53