title: Flexible electronics sensors for tactile multi-touching.
abstract: Flexible electronics sensors for tactile applications in multi-touch sensing and large scale manufacturing were designed and fabricated. The sensors are based on polyimide substrates, with thixotropy materials used to print organic resistances and a bump on the top polyimide layer. The gap between the bottom electrode layer and the resistance layer provides a buffer distance to reduce erroneous contact during large bending. Experimental results show that the top membrane with a bump protrusion and a resistance layer had a large deflection and a quick sensitive response. The bump and resistance layer provided a concentrated von Mises stress force and inertial force on the top membrane center. When the top membrane had no bump, it had a transient response delay time and took longer to reach steady-state. For printing thick structures of flexible electronics sensors, diffusion effects and dimensional shrinkages can be improved by using a paste material with a high viscosity. Linear algorithm matrixes with Gaussian elimination and control system scanning were used for multi-touch detection. Flexible electronics sensors were printed with a resistance thickness of about 32 μm and a bump thickness of about 0.2 mm. Feasibility studies show that printing technology is appropriate for large scale manufacturing, producing sensors at a low cost.
authors.affiliation: Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan; E-mail:  wenyang@itri.org.tw.
authors.forename: Wen-Yang
authors.initials: WY
authors.lastname: Chang
authors.forename: Te-Hua
authors.initials: TH
authors.lastname: Fang
authors.forename: Shao-Hsing
authors.initials: SH
authors.lastname: Yeh
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Lin