Keetronics developed a printed flexible heater for real time applications (Heat Therapy – Healthcare applications).It is fullyprinted resistive heating elements with conductive low resistance traces and unique high resistance arrays for heating surface applications, can create self temperature controlling heaters utilizing positive temperature coefficient (PTC) technology, or printed thermocouples to measure temperature. It works under the principle of electrical coil, where the magnetic flux induces with respect to voltage and current, achieved with the help of printing on flexible substrates. By control of dimensions and ink compositions these products offer precise resistance specifications without the need of resistor trimming. These heaters are safe, flexible, long durable and cost effective.
Figure 1. Pictorial view of printed flexible heater layer architecture with a thickness of 100 µm
The basic idea is to develop a heat from conductive materials. These materials have high conductivity and induce magnetic flux with respect to voltage. The conductive materials are deposited on to the flexible substrate with the help of conventional screen printing techniques. Printed flexible heaters, thin construction and low mass designs allow heat to transfer more efficiently than foil imprinted heaters. Uniform part temperatures are assured by matching power. Flexible Heaters' high temperature capability allows low wattage for faster heat-up and warm-up time with a supply input of 12 Vdc.
Figure 2. (a) Printed Flexible Heater covered with thermal stability fabric (b) Features of Printed Heater and its applications