How Does Touchscreen Technology Work?

We all use it, but how does touchscreen technology work? Well, there’s more than one way that a touchscreen operates, with many different types of touch screen available.

Essentially, all of them can detect where your finger is – unless, that is, you suffer from a techie affliction known as ‘Zombie finger’ which means that any form of touchscreen technology just won’t work for you. More on that later…

Meanwhile, here are the various types of touch screens currently to be found amongst the general public:


  • Apple touchscreen and capacitive technology


Most iPhones today work with capacitive touchscreen technology (CCT). This was actually invented way back in the 1960s but wasn’t really developed enough until 2007 – the year of the first iPhone. 

It involves layers of capacitive material with electric charges. Or, in other words, two layers of glass with an insulator in between. 

It’s when the electrical charge is broken that sensors in the phone can tell where the screen has been touched. This type of touchscreen is so advanced it can detect more than one finger at a time. Don’t try touching it with a plastic stylus and expecting a result though: plastic is an insulator.


  • Cashpoints and resistive touch screens


Ever wondered how bank cashpoint machines know exactly how much money to issue? Well, it’s all down to how much resistance it feels when you press that screen. 

This type of touchscreen has three layers with the top a flexible conductive type of plastic. A layer of glass sits underneath with the insulating material between both. Pressing the plastic top layer nudges the glass layer, causing an electrical circuit. A computer chip then identifies where the screen has been touched.


  • Surgeons and projected capacitive touch screens


Hospitals, science and various industries install projected capacitive touch screens because their sensitivity allows use with, for example, surgical gloves. 

This touchscreen consists of a layer of glass containing see-thru electrode films and an IC chip, resulting in a 3D electrostatic field just above the screen. The touchpoint is noted when there is a change in the electrical currents (i.e when a finger or stylus hits the screen).


  • Surface Acoustic Wave (SAW) touchscreen technology


Acoustic (ultrasonic sound) waves form a grid across the screen and when disrupted a microchip identifies the location. This works in a very similar way to that of infrared technology.

Read our blog about SAW technology for more information.


  • Sony reader books and Infra Red (IR) touchscreen technology


Infrared light rays from LEDs are used to form a grid. When a finger hits the screen, the light is blocked, allowing a computer chip to identify where the blockage is. This type of touchscreen is incredibly sensitive – to the extent even a bit of dirt can trigger it.


The cure for ‘Zombie finger’

But what of the ‘Zombie finger’ affliction we mentioned earlier? This does indeed exist for some individuals. It could be that their skin is so callused that the screen doesn’t pick up their finger (musicians may get this). 

Another reason could be that all fingers in the hand are unusually long and brushing the screen along with the index finger. The result is the screen is confused. 

One easy way round this – rather than changing career or surgery – is, of course, to buy a stylus!


How does touchscreen technology work? Get in touch!

For more answers and advice on touchscreen technology do get in touch with the team here at Acante. You can call us on on +44 (0)118 988 5522 or email via