Stretchability—The Metric for Stretchable Electrical Interconnects

Abstract

Stretchable circuit technology, as the name implies, allows an electronic circuit to adapt to its surroundings by elongating when an external force is applied. Based on this, early authors proposed a straightforward metric: stretchability—the percentage length increase the circuit can survive while remaining functional. However, when comparing technologies, this metric is often unreliable as it is heavily design dependent. This paper aims to demonstrate this shortcoming and proposes a series of alternate methods to evaluate the performance of a stretchable interconnect. These methods consider circuit volume, material usage, and the reliability of the technology. This analysis is then expanded to the direct current (DC) resistance measurement performed on these stretchable interconnects. A simple dead reckoning approach is demonstrated to estimate the magnitude of these measurement errors on the final measurement.

Stretchable Inorganic LED Displays with Double-Layer Modular Design for High Fill Factor

“…Then, we can adjust the device substrate (upper layer) to control the fill factor and design the stretchable interconnect (lower layer) to provide different degrees of stretchability. 45 Design samples are provided in the Supporting Information (see Figure S8).…”

“…To control the fill factor and stretchability of the display using the double-layer design, first, we determine the resolution and vertical connection pad size depending on the device’s purpose. Then, we can adjust the device substrate (upper layer) to control the fill factor and design the stretchable interconnect (lower layer) to provide different degrees of stretchability . Design samples are provided in the Supporting Information (see Figure S8).…”

Universal Testing Apparatus Implementing Various Repetitive Mechanical Deformations to Evaluate the Reliability of Flexible Electronic Devices

“…Moreover, the actual deformations that are experienced by flexible electronics when they are used commercially should be considered. Therefore, in addition to the representative research [ 10 , 11 , 12 ], there has also been a great deal of research related to the stability testing, material development, and design of thin flexible and stretchable devices: Both mechanical and electrical durability tests are usually conducted to ensure the reliability of the electrodes [ 3 , 4 , 13 , 14 ]; the effects of cyclic bending and/or tension on organic solar cells have been examined [ 15 , 16 ]; various materials that are suitable for flexible and stretchable devices have been developed [ 16 , 17 , 18 ]; and basic design methods for flexible device structure that are intended to enhance bending resistance have been proposed [ 19 , 20 , 21 , 22 ]. The final assessment step when determining the possibility of device commercialization is to perform a reliability test under repetitive mechanical loading.…”

Editorial for Special Issue on Flexible Electronics: Fabrication and Ubiquitous Integration

“…There are 10 papers published in this Special Issue, covering new strategies for a paradigm shift in the design [ 1 , 2 , 3 ], fabrication [ 4 , 5 , 6 , 7 ], and encapsulation [ 8 , 9 , 10 ] of next-generation flexible systems. Xiao et al [ 1 ] proposed an “island-bridge” strategy to design high-performance stretchable electronics composed of inorganic rigid components so that that can they can be conformally transferred to non-developable surfaces.…”

“…The design of stretchable electronic devices requires a metric to evaluate their performance. This metric is provided by Plovie et al [ 2 ] to evaluate the performance of stretchable interconnects.…”