Problem: A major OEM in the defense industry needed to keep an LCD screen of hand-held, battery-operated GPS radio functional down to -40°C.  Most dot matrix LCD screens lose sharpness and response speed below 0°C.  However, the challenge was to design a heater with the tightest resistance tolerance so that it could not only accommodate the wattage needed to warm up the LCD for optimal visibility within a precise time requirement, but to also minimize power consumption in order to extend battery lifetime as much as possible.


Solution: The solution was a design that provided close proximity and even distribution of heat to the LCD combined with the accuracy of an averaging temperature sensor. A Thermal-Clear transparent heater (a micro-thin wire element laid in a pattern between optical grade polyester sheets) sandwiched between the backlight and the LCD provided reliable heat without blocking light. By custom routing and profiling the wire element, only the exact amount of wattage needed to heat the LCD was utilized. Then, by laying a wire-wound averaging sensor  element in between the heating element, the sensor could provide the most accurate temperature reading of the LCD. This was due to not only its close proximity to the LCD but also because of its complete coverage which allowed for more efficient control of the heater. This design was a considerable improvement over the typically used point sensors positioned apart from the LCD that sense only ambient air temperature.

Engineering Tip: An integrated heater / sensor design was not only successful in providing the fastest warm-up time with the lowest possible power required, it also helped to meet weight and space restrictions and allowed for easier final assembly and a smaller parts list.

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"Critical Components for Defense, Aerospace & Global Security Applications" Industry Guide
From extremes of land, air and sea combat environments, to deep space missions, to security check points, learn how flex circuits, heaters and sensors prove themselves in the toughest conditions anywhere.

Minco designs, manufactures and markets critical components for critical applications. We are unsurpassed in our ability to integrate and assemble Thermofoil Heaters, Flex Circuits, Sensors and Instruments into a single component for greater efficiency. We will help you minimize the risk of product failure by providing highly reliable components and expert design services.