From smartphones & tablets to ATMs, point-of-sale and public information displays; from industrial, medical and agricultural to military, naval & aviation devices and beyond, most of us use capacitive touch screens every day – at home, at work and while out shopping. But exactly what are capacitive touch screens and how do they work?
What are Capacitive Touch Screens & How Do They Work?
In a nutshell, capacitive touch screens are control displays that use the conductivity of human fingers or specialised devices (capacitive gloves or pens) for input. So, how does this work?
Resistive touch panels detect input and subsequently perform the desired function by the pressure exerted upon them via a finger or stylus causing two separate conductive layers to be pressed together.
Capacitive touch panels, on the other hand, consist of a single substrate layer (glass, acrylic or polycarbonate) coated with a highly conductive transparent material (typically indium tin oxide) capable of storing electrical charges.
When a capacitive touch screen device is activated, it generates an electrostatic field across the screen. As the screen is touched by a human finger or a capacitive pen/glove, a small charge is drawn to the specific point of contact.
The change subsequently occurring within the electrostatic field is then measured to pinpoint the location of the touch.
In some devices, this is done by circuits arranged at the screen/panel’s corners. Upon detecting a touch, these circuits pass the relevant information on to the device’s controller to be processed and ‘translated’ into the required action/function.
On devices with multi-touch screens, more complex input is enabled by sensors being arranged not just at the screen’s corners, but across the screen in the shape of a grid.
Capacitive vs. Resistive Touch Screens
Their reliance on pressure makes resistive touch panels prone to ‘accidental’ activation/input in pockets, bags, etc. Over time, wear & tear on the panel’s two conductive layers may also result in lack of response when touched.
Capacitive screens, on the other hand, rely on the touching finger/specialised device’s conductivity to process the input information, which means they cannot be activated/caused to perform any given function by ‘accident’.
Requiring a much lighter touch (i.e. no pressure needed), they also allow for easier operation and are less prone to suffer wear & tear even when used heavily, as well as offering greater accuracy and high clarity.
Diamond Coatings Capacitive Touch Screens
Market-leading capacitive touch screen manufacturer Diamond Coatings produce X-Y resistive, ready-to-use capacitive screens ranging in size up to 1,000 mm x 1,000 mm and:
- On substrates including rigid or flexible plastic and glass
- With 90% visible transmission (equal to that of uncoated plastic/glass and higher than that of resistive touch screens, which is 70%) and
- Complete with all necessary chips, bonding, connections & patterning
We can also supply fully shielded capacitive screens and/or screens with various optional finishes (i.e. special optical, anti-reflective/anti-glare and/or hard coat coatings, etc.)
For more detailed information and/or advice/assistance with the design/development of the ideal capacitive touch panel/screen for your specific application, please get in touch with our technical experts on +44 (0) 121 550 9430 or +44 (0) 8451 360 603 today.