The touch screen of the car stereo system is a device for input and output of information by means of touch- and gesture-sensitive display. As you know, the screens of modern devices not only display an image but also allow you to interact with the device. That is, in fact, the touch screen is not a touch screen – it is an additional device that is installed on top of the display outside, protecting it and serving to enter the coordinates of the touch screen with a finger or other object. Let’s look at car stereo comparison and the most popular and frequently occurring to us the types of screens in this or that equipment, for example – car stereo.
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Resistive Touch Screen and How They Work
Resistive screens come in several types, four-wire, and five-wire. Let’s look at the principles of each of these types of resistive structure separately.
A four-wire resistive touch screen consists of several components, namely, a flexible plastic membrane and a glass panel. Both the membrane and the panel have a layer of resistive coating, and the space between them is filled with micro insulators evenly distributed across the working (active area, that’s where your finger comes into contact with the glass) area of the screen, isolating the conductive surfaces. At the moment of pressing the screen the membrane and the panel are closed, the signal goes to the controller of the analog-digital converter registering changes of resistance and converts it into a touchpoint in the form of a coordinate (X / Y).
The Reading Algorithm, In General Terms:
- Y-coordinate – +5V voltage is applied to the upper electrode, the lower one is ground. Right and left are connected by a short feed, and at this moment the voltage equal to Y-coordinate is checked on them.
- X-coordinate – in the same order 5V supply + ground is applied to the right electrode, and the coordinate equal to X is read from the upper and lower electrode.
Capacitive Touch Screens and How They Work
A surface capacitive screen is an AC conductor. It is a glass panel coated with a resistive material (tin oxide-indium oxide coating alloy). The electrodes in the capacitive touch screen are arranged at the corners, supplying a small, alternating voltage that is the same for all corners. The principle of operation of a surface capacitive touch screen is following. The moment a finger or other conductive object touches the screen, it leaks power (the stronger the pressure and the closer the finger is to the electrode, the greater the current and the lower the resistance of the monitor). In the corners, there are sensors that register the touchpoint and transmit the information to the computing controller of the touchpoint.
Earlier models of “capacitive screens” used direct current, this greatly simplified the design, but there were failures if the grounding was poor. In terms of reliability, a capacitive touch screen has a capacity of about 200 million presses, that’s about 6.5 years of pressing at an interval of one second, (the capacitive screen is waterproof and perfectly capable of dealing with non-conductive contaminants). The transparency of capacitive screens is 90%, but even with such excellent characteristics, there are still vulnerabilities.
Today, the screen, in addition to its direct function is also a device for entering information at the time of touching it. As with everything that generates interest and demand, there are a huge number of types and kinds of touch screens on the market, with different physical actions and principles in operation. Today we have considered the most popular and common types of screens for example car stereos.