The first touchscreen in a car appeared in 1986 in the seventh generation of the Buick Riviera. From a monochrome display on the center console, the driver controlled the climate, "music" and other secondary systems
The first touchscreen in a car appeared in 1986 in the seventh generation of the Buick Riviera. From a monochrome display on the center console, the driver controlled the climate, "music" and other secondary systems. The first touchscreen in a car appeared in 1986 in the seventh generation of the Buick Riviera. From a monochrome display on the center console, the driver controlled the climate, "music" and other secondary systems.
The technology of the touch screen was described in the second half of the 1960s, and working samples were demonstrated at the beginning of the next decade. Now more than a dozen possible design options are known, but all perform the same function - they react to contact with the screen. They differ in the accuracy of recognition of the point where they were touched, their durability, the degree of protection against dirt and damage, the ability to respond to finger pressure (sometimes even if one is wearing a glove) or the stylus. The choice of design usually depends on the intended application.
The requirements for automotive systems are the mildest. There is no direct aggressive effect, operation at low temperatures is short-lived, and keystrokes are relatively rare. The simplest option for such conditions is a four-wire resistive screen. It consists of a rigid glass surface and a flexible outer layer - a membrane. A resistive material is applied to the glass and membrane, and a dielectric between them. By clicking on the membrane, you push through the insulating layer. Contacts close, resistance changes - hence the name of the technology. The vertical and horizontal coordinates are calculated by the controller, taking alternately the readings of the voltage drop between one and the other pairs of electrodes.
Resistive screen device:
1 - glass
2 - resistive layer
3 - dielectric
4 - flexible membrane
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+ Low cost, responsive to touch with any item
Short-lived, low light transmission
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In a four-wire resistive screen, electrodes are located along the edges of the panels
Over time, the layer on the membrane erases, which reduces performance. Typically, the resource is no more than 3 million clicks - it is enough for car life. If a more durable design is required, five-wire technology is used. Four electrodes are placed in it at the corners of the inner glass layer. The fifth electrode is brought to the membrane itself. Here, the resistive layer is replaced by a conductive one. Touching the surface changes the voltage on the conductive layer, which serves as a signal to the controller to the beginning of the measurement of coordinates. This design lives ten times longer and also works even if the outer layer is damaged.
More advanced technology is capacitive touch screens. They are divided into surface and projection. The former are similar in structure to resistive ones, but there is no external soft layer. A conductive material is applied to the rigid glass, to which alternating current is supplied. Touching the screen causes a leakage of electricity, which captures the controller. Displays respond only to the current conductor - to the finger or stylus designed to work with this type of surface.
four
When the finger touches the surface-capacitive screen, current leakage occurs. The closer the finger is to the electrode, the lower the screen resistance and the higher the current strength. To calculate the coordinates of the controller, it is enough to interrogate the four corner electrodes and compare the received numbers
The next step is projection-capacitive monitors. The reverse side of the panel of these devices is equipped with a grid of electrodes, while the surface-capacitive ones have only four. Thanks to such an abundance, the multitouch function is realized here, that is, recognition of several touches at the same time. Convenient for scrolling pages or changing, for example, with two fingers the scale of the map on the screen. Both types of capacitive touchscreens have a long service life - more than 200 million clicks to one point.
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