Liquid-Crystal Display (LCD) Screen Thermal Testing to Simulate Solar Gain

The Boland View Port 20 inch liquid-crystal display LCD monitor was tested in order to determine a solution to failures observed when the monitor was used outdoors. In direct sunlight, screen temperatures went beyond the maximum operational temperature, causing the image to white out. Tests were first performed to determine the monitors baseline operations and maximum screen temperature before failure. A temperature chamber and heat lamp were used to simulate worst-case conditions. The next tests were performed outdoors to determine possible solutions to problem. In separate tests, the metal frame and the screen of the monitor were shaded from the sun, eliminating the solar loading from each area. Results were the most promising when the screen was shaded from the sun. After observing this behavior Hot Mirror glass from Dicrotec Thin Films was tested. This glass uses a coating that passes visible light, but reflects infrared light, reducing the total heat transmitted to the monitor from the sun. Satisfactory results were achieved when a 1 inch air gap was maintained between the monitor and glass. These results lead to several design recommendations to eliminate the failures previously observed with the Boland monitor.