There are some aspects of technology that I feel are taken for granted. They were revolutionary when the ideas were conceived, but now, since they are in every device. The technology behind certain features are complex which should lead to a greater appreciation for them. Touch screens are what best fit this description. I feel people believe touch screens to be simple when they are a pretty complex technology. (Warning, things are about to get extremely technical)
The first touchscreen was actually introduced in 1992 but they didn’t become popular in the public until the early 2000s. The technology seems so simple because so many different devices have touchscreens. Our phones, iPods, tablets, and even now laptops and monitors have touchscreen capabilities. Although it may seem simple based on the immense amount of objects that have them, the technology is actually pretty cool. There are three different types of systems: resistive, capacitive, and shock acoustic.
The resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These two layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole setup. An electrical current runs through the two layers while the monitor is operational. When the user touches the screen, the two layers make contact in that exact spot. The change in the electrical field is noted and the coordinates of the point of contact are calculated by the computer. Once the coordinates are known, a special driver translates the touch into something that the operating system (OS) can understand.
In the capacitive system, a layer that stores electrical charge is placed on the glass panel of the monitor. When the user touches the monitor with his or her finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor. The computer calculates, from the relative differences in charge at each corner, exactly where the touch event took place and then relays that information to the touch-screen driver software. One advantage that the capacitive system has over the resistive system is that it transmits almost 90 percent of the light from the monitor, whereas the resistive system only transmits about 75 percent. This gives the capacitive system a much clearer picture than the resistive system.
On the monitor of a surface acoustic wave system, two transducers (one receiving and one sending) are placed along the x and y axes of the monitor’s glass plate. Also placed on the glass are reflectors (they reflect an electrical signal sent from one transducer to the other). The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant, and can locate it accordingly. The wave setup has no metallic layers on the screen, allowing for 100-percent light throughput and perfect image clarity. This makes the surface acoustic wave system best for displaying detailed graphics.
As you can see, the technology behind touch screens is so complex. I hope this blog gives you a little more appreciation for them each time you open up an open using your finger.