Three-dimensional surface printing method for interconnecting electrodes on opposite sides of substrates

Md Khalilur Rahman,Thanh Huy Phung,Seong-Jun Kim,Kye-Si Kwon,Jaeryul Yu,Jin-Sol Lee

doi:10.1038/s41598-020-75556-x

Md Khalilur Rahman, Thanh Huy Phung + Show 4 more

Open Access

https://doi.org/10.1038/s41598-020-75556-x

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Abstract

As the application of the direct printing method becomes diversified, printing on substrates with non-flat surfaces is increasingly required. However, printing on three-dimensional surfaces suffers from a number of difficulties, which include ink flow due to gravity, and the connection of print lines over sharp edges. This study presents an effective way to print a fine pattern (~ 30 μm) on three different faces with sharp edge boundaries. The method uses a deflectable and stretchable jet stream of conductive ink, which is produced by near-field electrospinning (NFES) technique. Due to added polymer in the ink, the jet stream from the nozzle is less likely to be disconnected, even when it is deposited over sharp edges of objects. As a practical industrial application, we demonstrate that the method can be effectively used for recent display applications, which require the connection of electrical signal and power on both sides of the glass. When the total length of printed lines along the ‘Π’ shaped glass surfaces was 1.2 mm, we could achieve the average resistance of 0.84 Ω.

Highlights

As the application of the direct printing method becomes diversified, printing on substrates with non-flat surfaces is increasingly required
Most direct printing methods have been implemented on substrates with flat surface
We propose a printing method for connecting the electrodes on two opposite sides of glass substrates, which could be used in display application

Summary

Introduction

As the application of the direct printing method becomes diversified, printing on substrates with non-flat surfaces is increasingly required. As a practical industrial application, we demonstrate that the method can be effectively used for recent display applications, which require the connection of electrical signal and power on both sides of the glass. Most direct printing methods have been implemented on substrates with flat surface. In the case of using conventional methods for printing on surfaces of high curvature, the control of 3D motion could be difficult, and the process can be very slow, with poor deposition quality. Unlike printed circuit board (PCB) substrates, via holes for the connection of double-sided circuits are difficult to make, due to the brittleness of glass. Vertical faces due to the effect of gravity, unless the ink viscosity is very high. (2) The printing speed could be very slow, in order for the nozzle to follow such irregular surfaces with extremely large curvature. (3) In the case of conventional dispensers, it is difficult to achieve a fine line (< 100 μm), since a nozzle with inner diameter of more than 100 μm should be used for dispensing relatively highly viscous ink (~ 10,000 cP)

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