An electrostatic field is an essential element of a capacitive touchscreen. You won’t be able to see it, nor will you feel it. Nonetheless, capacitive touchscreens leverage an electrostatic field to detect touch commands. For a better understanding of electrostatic fields and the role they play in capacitive touchscreen technology, keep reading.
What Is an Electrostatic Field?
An electrostatic field is an electrically charged field around a charged object. Also known as a dielectric field, it will exert force upon other charged objects nearby.
There are surface capacitive touchscreens, and there are projected capacitive touchscreens. While they feature different designs, they both use an electrostatic field. It’s a defining characteristic of capacitive touchscreen technology, in fact.
How Capacitive Touchscreens Use an Electrostatic Field
Capacitive touchscreens use an electrostatic field to detect touch commands. Capacitive, of course, is one of several touchscreen technologies. From smartphones and tablets to computer monitors, smart appliances and more, many touchscreens use capacitive technology. These capacitive touchscreens produce an electrostatic field during use.
When you turn on a capacitive touchscreen, it will typically begin to produce an electrostatic field. At the same time, it will measure this field while looking for changes in capacitance. Performing a touch command with a bare finger — or any conductive object, such as a capacitive stylus — will result in a change in capacitance. Your finger will draw some of the electricity from the capacitive touchscreen to your body. The capacitive touchscreen will then register this change in capacitance as a touch event.
Do Other Touchscreens Use an Electrostatic Field?
Capacitive is the only major touchscreen technology that uses an electrostatic field. Resistive touchscreens rely on pressure to detect touch commands, so they don’t require an electrostatic field. Surface acoustic wave (SAW) touchscreens rely on ultrasonic sound waves to detect touch commands, so they don’t require an electrostatic field, either. And infrared grid (IR) touchscreens rely on IR light to detect touch commands, so they don’t require an electrostatic field.
Whether surface capacitive or projected capacitive, all capacitive touchscreens require an electrostatic field. They use it to detect touch commands. Capacitive touchscreens will produce a uniform electrostatic field, which they apply to the top layer via conductors. Touch commands involving a bare finger or conductive object will change the device’s capacitance. The capacitive touchscreen will then record the touch command and, thus, respond with the appropriate action.