In today’s gadget world touchscreens have become very famous from most common touchscreen of your mobile phone to touchscreens of many control devices.
But there might be always a question in your mind how touchscreens works?
Touchscreens take your command via your hand or your stylus touch. It sends command to mobile or other device to which it is connected to act accordingly. You might have seen two type of touchscreens one is where you can operate via stylus or hand. But in other type you can’t give command via stylus. Have you ever thought why this happened?
This happened because characteristic of both the touch screen is different. One was resistive where your hand and stylus worked. But another one is capacitive where only your hand works.
Actually touchscreens are of many types but here only three types of touch screen
·       1. Resistive
·        2.Capacitive
·        3.Surface acoustic wave
Resistive touchscreen: - The resistive type touchscreen system consists of panel made up of glass
and is covered with a conductive and a resistive metallic layer. There is a spacer between these two layers, and a scratch-resistant layer is placed on top of the whole setup so that layer could be scratch free and looks smooth all the time for users. When the monitor is in in operation an electrical current runs through the two layers. When a user touches the screen via his hand or stylus, the two layers make contact in that exact spot. When you touch the screen, change in the electrical field is noted and the coordinates of the touch point of contact are calculated by the computer. Once the coordinates are known to your mobile or computer, a special driver translates the touch into something that the operating system can understand, much as a computer mouse driver translates a mouse's movements into a click or a drag.
In the capacitive touchscreen system, same as of resistive type touchscreen there are two layers that store electrical charge on the panel of monitor. If you touch the monitor screen some of the charges is transferred to the user, so the charge on the capacitive layer decreases. Decrease in charge is measured by the circuits located at every place of the monitor or touch screen of your mobile. Circuit on the touch screen calculates 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. Driver transforms this message to further action. Capacitive touchscreen transmits almost 90% of light while resistive touchscreen transmits only 75%, so capacitive touchscreen’s picture is clearer than resistive touchscreen system.
But the most interesting thing is surface acoustic wave system touch screen, in this type of touch screen two transducers (one receiving and one sending) and are placed along the two axes( x and y) axes of the monitor's glass plate. There also placed a reflectors -- they reflect an electrical signal sent from one transducer to the other. The touching point is told by the receiving transmitter. If anything objects the receiving signal then it tells the same to driver by locating its x-y position on the screen. The wave setup has no metallic layers on the screen, thus this allows for 100-percent light throughput and perfect image clarity. So, from this you can say that Surface acoustic wave system is better than both mentioned above.
Another area in which the systems differ is in which stimuli will register as a touch event. A resistive system registers a touch as long as the two layers make contact, which means that it doesn't matter if you touch it with your finger or a rubber ball. A capacitive system, on the other hand, must have a conductive input, usually your finger, in order to register a touch. The surface acoustic wave system works much like the resistive system, allowing a touch with almost any object -- except hard and small objects like a pen tip.
As far as price, the resistive system is the cheapest; its clarity is the lowest of the three, and its layers can be damaged by sharp objects. The surface acoustic wave setup is usually the most expensive.