Environmental simulation test for climatic temperature fluctuations

Many touch applications are subject to sudden temperature shocks or very strong climatic temperature fluctuations. These include, for example, handhelds that are used in cold stores or out-door devices that are used in climatically extreme climates.

For all these applications, an environmental simulation test is recommended, which simulates the special environmental influences in the real conditions.

Temperature cycling tests can be used to determine the effects of frequent temperature changes in the later area of application. In addition to the difference in the test temperatures, an important factor here is the residence time in the different temperature zones.

However, the thermal shock method (according to DIN EN 60 068-2-14) is also used to achieve accelerated testing by means of thermal shock, which simulates real temperature fluctuations over the life cycle of a touch screen in a short time. The real temperature fluctuations are not as extreme as in the environmental simulation.

With the 2-chamber temperature shock, the touch screen is transferred from a lower test temperature to an upper test temperature. This procedure is repeated for a specified number of cycles. It is possible to change the temperature from -70 °C to up to +200 °C in just a few seconds.

Due to cyclic loads and the resulting accelerated aging, weak points are uncovered and optimization potentials are already visible on the touchscreen in the prototype phase.

The main fault mechanism in thermal shock concerns the functionality of the electronics and the expansion of the different materials of a touch panel.