All-Printed Differential Temperature Sensor for the Compensation of Bending Effects

Abstract

Because printed resistance temperature detectors (RTDs) are affected by tension and compression of metallic patterns on flexible or curved surfaces, a significant temperature-sensing error occurs in general. Hence, we propose a differential temperature sensor (DTS) to compensate the bending effect of the printed RTDs, which is composed of two serially connected similar meander patterns fabricated back-to-back on a polyimide polyethylene terephthalate substrate through a Dimatix DMP-3000 inkjet printer using silver nanoparticles. Under mechanical deformation, the resistance of the proposed DTS is not varied significantly under the same temperature environment because its patterns vary differentially as one side experiences tension while the opposite side experiences compression. A single meander pattern of the proposed DTS has a total length of 75 mm and device dimensions of 7 × 7 mm. The total resistance variation is observed to be 15.5 Ω against the temperature variation from 0 to 100 °C, and the temperature coefficient of resistance is 1.076 × 10 °C. The proposed DTS exhibits no significant resistance change on bendability testing down to 2 mm diameter because of mechanical deformation. In addition, it is also used to detect the curvature of a body shape down to 2 mm diameter because its resistance changes by ±8.22% using a single meander pattern of DTS. The proposed sensor can be applied on a curved or flexible surface to measure relatively accurate temperature when compared to a single meander pattern.

Recent Developments in Printing Flexible and Wearable Sensing Electronics for Healthcare Applications

“…A large variety of thermal sensors were developed in the last couple of years using intrinsic conducting and nanocomposite materials in different geometrical shapes to enable wearability at minimum bending angles [124]. An all-printing approach makes the fabrication of temperature sensors simple and cost-effective, allowing the development of single layers of patterned conducting lines in various shapes (meander, spiral, or circular).…”

Smart Manufacturing Technologies for Printed Electronics

“…The prominent challenges in printed electronics are material compatibility, substrate surface energy, viscosity of the materials' solution, and compatibility of dissimilar materials in multilayer structure, technology limitations in terms of film thickness, width, and height. As compared to conventional electronic manufacturing, printing technologies are revolutionizing the incredible field of flexible/bendable electronics by providing cost-effective routes for processing diverse electronic materials on nonplanar substrates at compatible temperatures [9][10][11][12]. Simplified processing steps, reduced materials' wastage, low-fabrication costs, and simple patterning techniques make printing technologies very attractive when compared to standard microfabrication in clean room processes.…”

Nickel Based RTD Fabricated via Additive Screen Printing Process for Flexible Electronics

“…Common resistive metals used in the fabrication of the RTD are metals such as platinum (Pt) [2], nickel (Ni) [5] and copper (Cu) [6]. In addition, gold (Au) and silver (Ag) have also been reported for temperature sensing applications [7], [8]. Among these, Pt is the commonly used resistive element in the fabrication of RTD due to its high accuracy in measuring temperatures.…”