The answer to the question of “Does heat affect touch screens?” is yes. The reason that these screens sometimes do not respond to finger pressure is because they are designed with a thin film of plastic or a semi-transparent layer of polycarbonate.
The heat sink portion of the touch screen is actually a very thin sheet of plastic that provides a barrier between the touch and the active surface of the unit. When the temperature gets very hot, the heat sink melts and contracts to reflect back the hot surface temperatures. However, when the surface temperatures start to fall, the heat sink begins to expand again and this is what causes it to respond to finger pressure. The screen does not respond to touch when the hot surface temperatures reach below the critical point, but the response to finger pressure is only seen at those times when the surface temperatures rise above the critical point.
Touch screen displays are based on a very simple and low-tech concept. A light beam of laser or electric energy strikes the screen and creates a pixel on the screen. This pixel then becomes the color of the image that was displayed. Touch screens have been used in electronics for decades. They have found their way into almost every electronic device that uses a display screen.
What most people don’t realize is that a touch-screen display does not have a backlit screen or one that automatically turns off when the temperature goes too high. There are two different types of touch screen displays: resistive and capacitive. Resistive displays work on a physical principle called the PIR (Pulse interrupts-Isoelectric) principle. When the voltage across the cells gets too high, they are forced to generate an Isovolt (me=V/Ira), which is a measure of how much current is produced. Capacitive displays work by passing an electric current through a switch that creates a change in current when the button is pressed.
The next question is how does heat affect the operation of a touch screen display. When you press a button on a resistive screen, it causes the pixel to generate an Isovolt. If the heat is high enough, it can cause the generation of heat bridges, which are like bridges between adjacent pixels. Heat bridges are formed when the temperature difference is large enough.
How does heat sensitive resistive and capacitive touch screen display work in reality? In a resistive screen, the heat is always kept at a constant temperature. As the finger interacts with the screen, the electric current flows through the circuits until it hits a conductive element. This element conducts the current into the next part of the circuit, which in turn, brings the current to a halt. This entire process happens over again until the finger no longer makes any contact with the screen. When the finger does make contact, the circuits are designed in such a way that the current is again flowing smoothly.