Lee Sang Hoon, Lee Sangyoon
Department of Mechanical Design and Production Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
Department of Mechanical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea.
ACS Appl Mater Interfaces. 2020 Oct 14;12(41):46797-46803. doi: 10.1021/acsami.0c14889. Epub 2020 Oct 2.
It is common in the field of printed electronics that polydimethylsiloxane (PDMS) be used as a dielectric layer for capacitive sensors because of its high elasticity and restoration force. However, capacitive sensors with the PDMS dielectric layer have a lower sensitivity than those with an air-gap structure that has been fabricated by the conventional micro-electromechanical system (MEMS) process. This paper presents a productive method for fabricating air-gap structures for touch sensors by roll-to-roll slot-die coating. The air-gap is formed by coating and removing a sacrificial layer. Cantilever-structured capacitive touch sensors with an air-gap are fabricated as follows: First, the bottom electrode, the dielectric layer, and the poly(vinyl alcohol) (PVA) sacrificial layer are roll-to-roll slot-die-coated on a flexible substrate. In addition, the spacer layer is spin-coated. On the sacrificial and spacer layers, the top electrode and structural layer are formed by spin-coating. Then, the air-gap and cantilever structure are made by removing the sacrificial layer in water. The cantilever-structured sensor samples are examined in terms of sensitivity, hysteresis, and repeatability. In particular, the electrical performance of the samples is compared to those with the PDMS dielectric layer. Experimental results show that the cantilever-structured sensor samples have significantly higher sensitivity compared to those with the PDMS dielectric layer.
在印刷电子领域，聚二甲基硅氧烷（PDMS）因其高弹性和恢复力而常用于电容式传感器的介电层。然而，具有PDMS介电层的电容式传感器的灵敏度低于通过传统微机电系统（MEMS）工艺制造的具有气隙结构的传感器。本文提出了一种通过卷对卷狭缝模涂覆制造触摸传感器气隙结构的有效方法。气隙通过涂覆和去除牺牲层形成。具有气隙的悬臂结构电容式触摸传感器的制造过程如下：首先，将底部电极、介电层和聚乙烯醇（PVA）牺牲层通过卷对卷狭缝模涂覆在柔性基板上。此外，旋涂间隔层。在牺牲层和间隔层上，通过旋涂形成顶部电极和结构层。然后，通过在水中去除牺牲层来制造气隙和悬臂结构。对悬臂结构的传感器样品进行灵敏度、滞后和重复性方面的测试。特别是，将样品的电学性能与具有PDMS介电层的样品进行比较。实验结果表明，与具有PDMS介电层的传感器样品相比，悬臂结构的传感器样品具有显著更高的灵敏度。
