How Does a Projected Capacitive Touchscreen Work?

Sep 30, 2019

Projected capacitive touchscreens have become increasingly popular in recent years. Like other capacitive touchscreens, they are designed to measure a uniform electrostatic field to detect touch commands. When you tap or touch the display interface with a bare finger — or any conductive object for that matter — the voltage will drop. Capacitive touchscreens register this voltage reduction as a touch command. While all capacitive touchscreens use this basic mechanism to detect touch commands, there are several different types of capacitive technology, one of the most popular being projected capacitive.

Projected Capacitive Touchscreens Explained

Also known as PCT or PCAP, projected capacitive is a form of touchscreen technology that’s used in smartphones, tablets, human machine interfaces (HMIs) and dozens of other touchscreen devices. It’s essentially the same as surface capacitive technology but with a few added upgrades.

Projected capacitive touchscreens, for example, are designed with more electrodes than their surface capacitive counterparts. As a result, they support a greater number of touch commands. Some projected capacitive touchscreens, in fact, support touch commands in thousands of different areas on the display interface.

How Projected Capacitive Touchscreens Work

Although there are different ways to design and manufacture a projected capacitive touchscreen, most feature an X-Y grid of intersecting electrodes. The intersecting electrodes are made of a conductive material that, when exposed to a similar conductive material, allows for a reduction of voltage.

Tapping or touching the display interface of a projected capacitive touchscreen will cause the device’s voltage to drop. When a projected capacitive touchscreen is turned on, electricity runs through the X-Y grid of intersecting electrodes. And if you tap or touch the display interface, your finger or stylus will absorb some of the electricity from that area, which the device registers as a touch command.

The Benefits of Projected Capacitive Touchscreens

Projected capacitive touchscreens offer several benefits over other types of touchscreen devices. They are able to support multi-touch commands, for instance. With multi-touch functionality, you can perform touch commands using two or more simultaneously points of contact.

In addition to multi-touch functionality, projected capacitive touchscreens may also support touch commands with a gloved finger. Assuming you are wearing thin gloves, such as surgical gloves, the projected capacitive touchscreen should register your touch command.

Projected capacitive touchscreens also produce images in higher resolution than other types of touchscreen devices. For these reasons and others, projected capacitive touchscreens are often preferred by businesses owners and consumers alike.

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