January 12, 2010


Posted in touch phone tagged , , , at 1:23 am by grace

Now days “touch screens” are most popular among smart phone and touch phone users . This is one of the main tools to attract several eyes at a time. So many peoples are preferred to go with touch phone. So the providers also acts accordingly.

 Here we can see, what are the technology has been used over touch screen. There are several number of technologies have been used in touch phone’s touch screen.

The first one is capacitive.

It consists an insulator which has been coated with transparent conductor [here ITO indium tin oxide]. Its electrostatic field senses some touches [mostly from human body. Though human body also a conductor, both will be matched perfectly] over it. So they are give some alternative or opposite force over the touch area. That can be measurable in terms of Capacitance. There so many technologies have been used to identify this touch location. A computer software can easily identifies the touch location and further it will act depends upon the touch location.

The next technology is surface capacitance.

In this surface capacitance technology only one side will be coated by conductive layer. So insulators other side will remains coating free. If we apply some small amount of voltage on its field, then a uniform electrostatic field will be created as per the input voltage. Here we can replace the conductor with our finger. In case our human finger will touches that uncoated area, then a capacitor will be created dynamically.

Depends upon the change in the capacitance measurement, sensor’s controller can able o determine the location of the touch area indirectly.

As it is moderately durable but has limited resolution. In further it is prone to false signals from parasitic capacitive coupling and it requires calibration during the production.

Above these two technologies are mostly used to build a common ‘Touch phone’.

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