It’s no secret that cathode-ray tube (CRT) displays and magnets don’t mix. When exposed to a magnetic field, CRTs may become permanently disclosed. In the past, TVs and other displays that used CRT technology would often succumb to magnet-related damage. This leads many people to assume that touchscreens can be damaged by magnets as well. After all, touchscreens feature an integrated display. But the good news is that magnets won’t damage touchscreens.
How Magnets Damage CRTs
Magnets damage CRTs by distorting their electrons. All CRTs use electrons to produce their visible images. They feature a vacuum tube with an electron gun. When turned on, the electron gun will blast the CRT’s phosphorescent pixels with electrons, thus creating visible images. Magnets, though, interfere with this process. They will redirect the electrons produced by the electron gun. The end result is visual distortion that manifests in the form of dark spots or discoloration.
Why Touchscreens Are Safe From Magnets
They may damage CRTs, but you can rest assured knowing that touchscreens are safe from magnets. Touchscreens don’t use CRT technology. Whether it’s a smartphone, tablet, human machine interface (HMI) or any other touchscreen, it will likely feature an liquid-crystal display (LCD). Most touchscreens use LCD technology for their respective display.
Unlike CRTs, LCDs don’t use an electron gun to produce images. Instead, they use a backlighting system — typically a light-emitting diode (LED) backlighting system — along with a layer of liquid pixels and polarizers. The backlighting system selectively illuminates the pixels through the polarizes. Even when exposed to a magnetic field, all of these parts will continue to function as intended.
Magnets won’t interfere with touchscreens’ ability to detect touch commands, either. Touchscreens have an integrated display, and they have a touch-detection system, the latter of which is simply the touchscreen technology that powers a given touchscreen. Common touchscreen technologies include capacitive and resistive.
Capacitive touchscreen technology works by measuring capacitance. Resistive touchscreen technology works by using multiple layers of an electrically resistive material with patterned electrodes or conductive traces facing each other. Whether capacitive or resistive, touchscreens will continue to detect touch commands in the presence of a magnetic field. Magnets won’t prevent them from measuring capacitance, nor will magnets damage the electrically resistive layers of a resistive touchscreen.
You can rest assured knowing that magnets won’t damage touchscreens. Magnets won’t interfere with touchscreens’ integrated LCDs, nor will they interfere with touchscreens’ ability to detect touch commands.