 Touchscreens in general
First off I love seeing support by the manufacturer in this forum, especially with good information.
I repair touchscreen devices for a living. I've probably replaced 2000 digitizers in the last two years. Use a screen protector!
Touchscreens are made with a glass plated covered with a conductive surface, then a very thin gel, then a plastic cover layer (that's conductive under neath). When you press on the screen you push the gel out of the way and make contact between the two conductive surfaces. The "device" reads the location by reading the resistance along the side and top of the digitizer (it has a resistive material along the edges where you can't see). What you are doing by pressing different places is changing the amount of that side/top resistance. If you are familiar with math you are using quadrant A of a cartitian coordinates system. But don't worry about the terms.
The device can see where you tap and the location is calculated.
If something is pressing the two layers together, anything, that is the only "tap" you can have. The first tap must be released before it can see another tap. That's why crud under the gasket on the sides (where you can't see) can cause this problem. It's also why if you get deep scratches the digitizer will either stop working all together (already sees a tap) or be misaligned. The misalignment is easy to explain. If the surface is creased it is closer to the glass in that spot. If you try to tap near it, the depression makes contact first and the device sees that location instead of where you were tapping.
Bottom line, use a screen protector and keep the screen clean. Even dust on the tip of the stylus can scratch up the digitizer surface. |