Types of touch screen in mobile devices

The market for mobile devices, point to touch screens, and a market in constant renewal, we need to know how to buy and how to differentiate the different types of touch screens that can be found in mobile phones.

There are three types of touch screens: the capacitive (iPhone 4), the resistive (Nokia N97) and the infrared (Samsung U600) ones.

How do touch screens work?

There are basic differences in the functioning of these two types of technology. Resistiv escreens are composed of various layers. The commands for finger or stylus are made ​​in the outer layer, which comes into contact with a flexible protective membrane. The third layer is the first screen, that touches the screen and closes the circuit. These type of screens don’t support multi-touch, because the circuits can be in conflict.

Capacitive screens are composed of a layer of protection, one with the transparent electrodes and immediately the glass substrate. They are the electrodes that capture the commands: electrical induction of the fingers makes this layer with action sends the signals to the software running.

The oldest and easy to understand is the infrared system. At the edges of the screen there are some infrared emitters and receivers. On one side of the screen are the transmitters and on the other side are the receivers. We have a matrix of vertical and horizontal infrared. Pressing with your finger or any object on the screen interrupt an infrared beam vertical and horizontal. The system detects what rays have been interrupted, thus knows where we hold and act on consequences.

Advantages and disadvantages of touch screens types

The three technologies have some advantages. The resistive earn points for being cheaper and enable small manufacturers also get touch-sensitive screens offer to their customers.There is also an advantage related to the climate. On very cold days, people are wearing gloves fail to use capacitive screens. That’s because what makes the commands work is the power of the fingers, which are not contacting the device. For this reason, resistive screens are more appropriate local cold.

On the other hand, capacitive screens acquire many points for image quality and speed of response commands. When the software allows capacitive screens can be operated at several different points, without interference from one point over another. It’s multitouch.

Another point that is higher capacitive screens is brightness. The resistive many problems relating to reflection, making it difficult to use in environments with high luminosity. Because they have fewer layers capacitive, the brightness is more intense and better ensures quality visualizations.

Finally infrared touch screens have the advantage of simplicity and not obscure the screen, but have obvious drawbacks: they are expensive and bulky, very sencible to dirt and can easily detect false clicks (an insect that pose, for example).