Highly Flexible Touch Screen Panel Fabricated with Silver Nanowire Crossing Electrodes and Transparent Bridges

Abstract

A capacitive-type touch screen panel (TSP) composed of silver nanowire (AgNW) crossing electrodes and transparent bridge structures was fabricated on a polycarbonate film. The transparent bridge structure was formed with a stack of Al-doped ZnO (AZO) electrodes and SU-8 insulator. The stable and robust continuity of the bridge electrode over the bridge insulator was achieved by making the side-wall slope of the bridge insulator low and depositing the conformal AZO film with atomic layer deposition. With an extended exposure time of photolithography, the lower part of the SU-8 layer around the region uncovered by the photomask can be exposed enough to the UV light scattered from the substrate. This leads to the low side-wall slope of the bridge insulator. The fabricated TSP sample showed a large capacitance change of 22.71% between with and without touching. Our work supplies the technological clue for ensuring long-term reliability to the highly flexible and transparent TSP made by using conventional fabrication processes.

Low‐Cost Fabrication Method for Thin, Flexible, and Transparent Touch Screen Sensors

“…Touch screens can be classified into several types according to their sensing methods, [ 1,3 ] and of these, capacitive sensing has been widely used due to its durability, performance, simultaneous multitouch and highly sensitive sensing capabilities. [ 1,4–7 ] In capacitive sensing, the touch location of the finger or stylus can be determined by scanning for a change in capacitance at each location. Electrode arrays are arranged in two sheets of film with each of the X and Y axes, and these two axes can be used as driving (or transmitter) and sensing (or receiver) electrodes, respectively.…”

“…However, in the case of bridge electrode patterning, a large amount of deposited material should be removed due to the small dimensions of the bridge electrodes, which results in a huge waste of materials. [ 7 ] In addition, a low yield can occur due to process difficulties. To overcome such problems, a proper fabrication method should be developed for bridge electrodes, which has been a critical issue for TSP manufacturers.…”

“…Due to the thickness of the pads and insulating layers, the printing surface may not be considered as a flat surface. The insulating layer did not influence the printing results because it was a considerably thin layer of several hundreds of nanometers, [ 7,12 ] and the printed lines could pass over the insulating area easily (Figure 2b,c). On the other hand, the thickness of the readout pads was about 5 µm, which is significantly thicker than the printed line thickness (≈1 µm).…”

Fabrication and Applications of Flexible Transparent Electrodes Based on Silver Nanowires

“…techniques are compatible with low-energy deposition process and without any vacuum equipment. Direct laser ablation [13,75], shadow mask [11], chemical etching using the photolithography process [76] are all the patterning strategies for flexible transparent electrodes.…”

Fabrication and performance of an ultrafine silver grid film applied to flexible touch sensor

“…As a pivotal component of many photoelectric products described by Chung et al [1] including solar cells studied by Yang et al [2], liquid crystal displays (LCDs) reported by Blake et al [3], organic light-emitting diodes(OLEDs) shown by Wu et al [4] and touch screen panels (TSPs) discussed by Jeon et al [5] and Kim et al [6], conductive electrodes have attracted more and more attention. Indium tin oxide (ITO) is the most widely used transparent conductive electrode material owing to its excellent optoelectronic properties.…”