Keywords:How Touch Screen Technology Works, Resistive Touch Screen, Capacitive Touch Screen, Surface Acoustic Touch Screen
Touch screen technology is being widely used now a days. You can see it in ATM’s or your smart phones , tabs etc. The world is full of the examples where this technology making user experience more interesting. From a long time I was thinking to write about it as how it exactly works, so here I am.
There are three basic system or you can say types of touch screen, that are used to recognize a person’s touch.
- Resistive Touch Screen
- Capacitive Touch Screen
- Surface acoustic wave Touch Screen
- Resistive Touch Screen : In this type of touch screen, a normal glass panel covered with a conductive and a resistive metallic layer is used. 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 a user touches the screen, the two layers make contact in that exact spot. The change in the electrical field is noted and the coordinates(x-y) of the point of contact are calculated by the controller. Controller then converts these known coordinates into operating system specific instructions by using special driver program.
- Capacitive Touch Screen : In this type of touch screen, a layer is placed over the glass panel of the screen. This layer stores electrical charge. When a person touches the screen with his or her finger, some of the charge from capacitive layer is transferred to the person, so the charge on the capacitive layer decreases. This change in charge on capacitive layer is measured in circuitslocated at each corner of the screen. The controller 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.
- Surface acoustic wave Touch Screen : In this type of touch screen, one receiving transducer and one sending transducer are used. They are placed along x and y axes of the screen’s glass plate. The glass also have reflectors placed over it. These reflectors reflect an electrical signal from one transducer to the other.When a person touch the screen it produces a wave , then it gets transformed into energy and detected by the receiving transducer.
|Resistive Touch||Capacitive Touch||Surface acoustic wave Touch|
|Cheap||Costly than Resistive||Costly|
|A resistive system register the touch as long as the two layers make contact . Can work with if user having gloves on his hand.||It must have a conductive input, usually your finger, in order to register a touch. Can’t register a touch if user has gloves on his hand.||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.|
|It transmit almost 75 percent of light from the screen, hence display quality is poor.||It transmits almost 90 percent of the light from the screen, hence better display.||It transmit 100 percent light from the screen hence gives best display experience to user.|
It was just a brief article about touch screen technology, when time will permit I’ll explain here on Techawarey how other functions work on touch screen like zooming a picture on I-phone or Samsung. Please Like and share.. 🙂 and keep reading…. :):)
Note: Source of images used in this articles are as below:
1.Resistive Touch Screen – www.techobilz.com
2.Capacitive Touch Screen www.edn.com
3. Surface Acoustic Wave Touch Screen – www.venturaautomation.com