How Water Affects Touchscreen Functionality

It’s no secret that water and electronics don’t mix. Saturating your smartphone or tablet in water will likely render it unusable. However, exposing these same devices to just a couple drops of moisture shouldn’t cause any major problems. With that said, small amounts of moisture may still affect the function of a touchscreen device, which is why it’s important for users to understand how their respective devices work.

Capacitive Touchscreen

We’ve talked about this before on the En-Touch blog, but it’s worth mentioning again that there are two primary types of touchscreen technology: resistive and capacitive. Resistive touchscreens register touch be squeezing two layers together. These layers are separated by air or some inert gas/substance, so when you press it the two layers touch.

Capacitive technology differs in the sense that it registers touch based on the operator’s electrical current. The human body is an excellent conductor of electricity. When you press your finger against a capacitive touchscreen device, it causes subtle changes to occur within the device’s electrostatic field.

Water and Capacitive Touchscreens

Resistive touchscreens are generally less susceptible to the effects of water and moisture than their capacitive counterpart. This is due to the fact that resistive touchscreens register touch based on pressure (e.g. squeezing the two layers together). But the vast majority of touchscreen smartphones and tablets manufactured today feature capacitive technology, which can result in some inconsistencies when they are exposed to moisture.

The problem with water and capacitive touchscreens lies in its effect on electrical currents. Even small amounts of moisture, such as a drop of sweat or rain, may provide another conduit for the device’s electrodes. Capacitive touchscreens may view excess moisture as the operator’s finger; thus, registering a touch wherever moisture is present. This isn’t a huge issue, but it’s still enough to affect the accuracy and overall performance of a touchscreen device.

Self-Capacitance

There’s a solution to this problem, however: self-capacitance technology. This relatively new form of touchscreen technology registers touch by measuring the electrical charge increase between each individual electrode on the screen and the operator’s ground. Because rain, sweat, and other droplets of moisture aren’t grounded, they won’t be registered as a touch.