A capacitive screen is a type of capacitive sensor that is made up of an electrical insulation layer and is covered with a transparent conductor. Since the human body is an electrical conductor, when contact is made with the surface of said screen, a distortion of the electromagnetic field thereof is generated. This field is measured thanks to the change in capacitance, also called electrical capacity.
For this you can use different technologies. The position must be sent to the controller for processing. In addition, this type of screens allow to obtain a higher quality image, with an improved response and, in some cases, the use of several fingers at the same time. However, these are more expensive screens and should not be used with a common type pointer, but will require a specific pointer for a capacitive screen.
The first person to develop a touch screen was EA Johnson, in 1965. However, the tablet, with the ability to detect a single touch, was not patented until 1969, and it was the technology that was used until 1995 in the tasks of air traffic control.
At the same time, Bent Stumpe and Fran Beck, scientists working at CERN, were the first to create a capacitive and transparent touch screen. This took place in the early 70’s of the twentieth century. However, this screen was based on offering pressure on an object on the surface, which meant the creation of the stylus.
How does a capacitive screen work?
These types of screens are the ones that currently surround us. In fact, they are the screens of most of the current mobile phones. The operation is based on the fact that a fixed mass, which is the screen itself, is charged with electricity. This load is plan and static. However, when we press on the screen, this electric charge changes, which causes it to stop being flat and, in this way, the area where pressure has been applied is detected.
When you want to use a screen with the ability to detect multiple points of contact, for example when zooming with two fingers, in addition to the screen itself, you will need special software. This software must be adequate and powerful enough to understand what is happening on the screen with respect to the electric field so as not to confuse the points that are being pressed.
A capacitive screen works by capacitance. This implies that it entails a much faster and more intuitive experience when the user uses it. These screens do not require any kind of pressure or force to carry out the action. On the contrary, it is enough to support the finger gently on the screen.
Another advantage is that it is a system that offers the ability to support several screen touches at the same time, which is known as multi-touch. In this way, the speed of interaction can be further extended by allowing different orders to be executed at the same time.
Fin more detailed information in this video: