Types of touch screen in mobile devices
The mobile devices market is a market that’s in constant renewal, so we need to know how to buy and how to differentiate the different types of touchscreens.
There are three types of touch screens: capacitive (iPhone 4), resistive (Nokia N97) and infrared (Samsung U600).
How do touch screens work?
There are some basic differences in the way these two types of technology work. Resistive screens are made out of various layers. The commands for finger or stylus are made in the outer layer, which comes into contact with a flexible and protective membrane. The third layer is the first screen, that touches the screen and closes the circuit. This type of screens doesn’t support multi-touch, because the circuits can come in conflict.
Capacitive screens are made out of a protection layer, one with transparent electrodes and glass substrate. These electrodes are the ones that capture commands. The electrical induction of the fingers enables this layer to send signals to the running software.
The oldest and easiest to understand kind of screen is the infrared one. At the edges of the screen there are several infrared emitters and receivers. The transmitters are placed on one side of the screen and the receivers are placed on the other side. We have a matrix of vertical and horizontal infrared. If you press the screen with your finger, any infrared beam (vertical and horizontal) is interrupted. The system detects what rays have been interrupted, thus it knows what area of the screen we’re pressing and acts accordingly.
Advantages and disadvantages of touch screens types
The three technologies have several advantages. The resistive one earn points for being cheaper and because it enables small manufacturers to also be able to offer touchscreen devices to their customers. There is also an advantage related to weather. On very cold days, people wearing gloves cannot use capacitive screens. This happens because what makes the commands work is the power of the fingers, which is impossible when users wear gloves. This is why resistive screens are more appropriate for cold weather.
On the other hand, capacitive screens earn many points for image quality and speed of response commands. When the software allows capacitive screens to be operated at several different points, without any interference. It’s multitouch.
Another thing that makes capacitive screens better is their brightness. Resistive screens have many problems related to reflection, making it difficult to use them in environments with high luminosity. Resistive screen’s brightness is more intense and it ensures high quality visualizations, because they have fewer capacitive layers.
Finally, infrared touch screens present the following advantage: simplicity and and the fact that they do not obscure the screen. But they also present several drawbacks: they are expensive and bulky, very sensible to dirt. They can easily detect false clicks.
Testing the sensibility and resolution of mobile screens
MOTO Labs tested both factors, sensibility and resolution in order to better understand the main differences between mobile screens such as iPhone, Google Nexus One, Motorola Droid, Palm Pre, and Blackberry Storm 2.