Technology has never advanced as fast as it has in the past decade. That includes the technologies used for touch screens; existing technologies have improved, and new technologies have been developed. This makes it just a little difficult to determine the best touch screen technology, or even keep track of how many different ones there are.
With the number of different uses for interactive screens from smart phones, to information screens, ATM’s and interactive whiteboards, we cannot be faulted for comparing the different touch technologies. To arrive at a better decision, however, would require listing the pros and cons of at least the most popular touch technologies in use. Only when we have done that will we be able to decide the best touch screen technology.
The Five Most Common Touch Technologies
One of the most affordable touch screen technologies uses light to determine touch location. Infrared (IR) touch screens have pairs of infrared emitters and sensors installed on vertical and horizontal bezels around the screen. The infrared beams create a grid of light that gets broken when a finger touches the surface of the screen. This allows x and y location of touch to be established. These types of screens are durable and provide very clear images. However, these types of screens are sensitive to bright light, dust, rain, or snow, each of which can cause interferences.
Resistive touch screens are also relatively affordable. This type of touch screen has two sets of conductors; one set horizontal and the other one vertical. An inner layer usually made of glass has one set and the other set is attached to a flexible outer layer which is usually made of plastic, with spacers in between. When the flexible outer layer of the screen is touched, conductors meet, the resistance reading changes and the point of touch is established. These screens are reliable but suffer from poor scratch resistance and low image clarity.
Surface capacitive screens have two rigid panels which enclose a layer of charged transparent electrode. When a finger touches the screen, the capacitance varies just enough to enable the internal software to determine pint of contact. These screens offer clear images and fast touch response. However, they need to be touched by a conductor such as an uncovered finger, and are sensitive to EMI/RFI.
In projected capacitive screens, a chip projects a 3D electrostatic field whose capacitance varies when touched by a charged device which can even be a gloved finger; points of contact are then established. This is more robust than surface capacitive technology, but also suffers from EMI/RFI sensitivity.
Surface Acoustic Wave (SAW) screens work almost the same way as IR screens except they use sound transducers and receivers to produce a grid of ultrasonic waves instead of using infrared. Touch disturbs the sound waves enough to pinpoint location. SAW screens have clear images but are sensitive to solid objects, surface contaminants and water droplets.
It is clear that each type of screen has its strengths and weaknesses. The best touch screen technology for you would be the one which fit your intended use best. If portability is your priority, a recent article says the Japanese have developed foldable touch screens.