interactive screens
Five types of
touchscreen
Touchscreens come in several varieties, but are all
interactive screens created equal?
By Olea Kiosks - www.olea.com
Although interactive touchscreens have
been around in one form or another
since the late 1970s, over the past 10
years or so they’ve become an integral
part of our lives. In fact, thanks to the
iPhone, tablet computers and similar
devices, we’ve become accustomed to
the idea that we should be able to touch
the screens we see and get a reaction.
Interactive touchscreens are a central
feature of devices ranging from ATMs
to wayfinding kiosks to the photo kiosks
commonly found in a variety of shops
around the world.
Stacking them up
Interactive displays include a variety of
technologies, and not every technology
is suited to every application. According
to the industry trade publication Control
Design, there are five main types of
touchscreens: resistive touch, infrared
touch, surface capacitive, surface
acoustical wave and projected capacitive.
Each has advantages, disadvantages and
applications for which it's best suited.
A resistive touchscreen is made
up of several thin layers, including
two electrically resistive layers facing
each other with a thin gap between.
When the top layer is touched, the two
layers connect and the screen detects
the position of that touch. In addition,
resistive touchscreens are unable to
perform the multi-touch functions that
are becoming increasingly popular.
For very large displays, infrared touch
is the most common application. Instead
of a sandwich of screens, infrared
touchscreens use IR emitters and
receivers to create an invisible grid of
beams across the display surface. When
an object such as a finger interrupts the
grid, sensors on the display are able to
locate the exact point.
Advantages of infrared touch are
excellent image quality and a long life,
and they work great for gesture-based
applications. In addition, scratches on
the screen itself won’t affect functionality.
In many cases, touch capability can be
added to a display through the use of a
third party overlay placed on the existing
screen.
On the downside, infrared
touchscreens are susceptible to
accidental activation and malfunctions
due to dirt or grease build-up. They’re
also not suited to outdoor applications.
In addition, while adding an overlay is
a relatively quick way to convert a large
display into a touchscreen, extra care
must be taken in mounting that overlay
to ensure touches match the image
displayed on the screen.
Surface capacitive screens have a
connective coating applied to the front
surface and a small voltage is applied
to each corner. Touching the screen
creates