Resistive touchscreens remain a popular choice for consumer and commercial applications. Like all touchscreens, they are able to detect and respond to touch commands. You can tap the surface of a resistive touchscreen to control it. While other types of touchscreens may use capacitance or ultrasonic waves, however, resistive touchscreens use a simpler method of operation. They feature several layers in their construction that allow them to detect touch commands.
Top and Bottom Layers
Resistive touchscreens feature a top layer and a bottom layer. Using these two layers, they are able to identify the location of touch commands.
The top and bottom layers contain electrodes. On the underside of the top layer are electrodes. The top side of the bottom layer features similar electrodes. Therefore, the two layers feature electrodes that face each other.
The electrodes on the top and bottom layers typically consist of indium tin oxide (ITO). ITO is highly conductive. Electricity can easily travel through ITO, making it ideal for use in electrodes.
The Layers Are Separated By Default
The top and bottom layers don’t actually touch each other — at least not until a touch command is performed. Rather, they are separated by a thin layer of air or inert gas.
Since the two layers don’t touch, the electrodes don’t touch, either. It’s not until you perform a touch command when the electrodes will make contact.
A Voltage Is Applied to One of the Layers
Resistive touchscreens work by applying a voltage to one of the two layers. When turned on, a resistive touchscreen will apply the voltage to its bottom or top layer. The other layer will then sense this voltage.
By default, the top and bottom layers are separated by a layer of air or inert gas. As a result, the resistive touchscreen “sensing” layer won’t detect the voltage. When you perform a touch command, though, you’ll press the top layer into the bottom layer. The electrodes on both of the layers will make contact, allowing for the “sensing” layer to detect the voltage. The resistive touchscreen will then register a touch event in the location of the voltage.
Resistive vs Capacitive Touchscreens
In addition to resistive, there are capacitive touchscreens. Capacitive touchscreens feature a different construction that allows them to detect touch commands.
While resistive touchscreens feature two layers with patterned electrodes, capacitive touchscreens feature an insulator layer with a transparent conductor. They work by generating a uniform electrostatic field. The electrostatic field will travel across the insulator layer on top of the capacitive touchscreen. The capacitive touchscreen will then measure this electrostatic field. Any change in capacitance indicates a touch command.
