P‐200L: Late‐News Poster: Sensing Touch by Sensing Force

Abstract

Directly measuring the force of a touch on a touch screen eliminates the limitations of traditional touch technologies. Force sensing touch devices heretofore have proven impractical. We explore the challenges of force-based touch sensing, how these are overcome, and the capabilities thus offered to the design engineer.

32.5L: Late‐News Paper: Multitouch Pixilated Force Sensing Touch Screen

“…One way to achieve force sensing is to use strain gauges at the corners of a touch panel. The position of touch can be determined by the ratios of force readings from each of the four corners [4]. However, it is designed for larger panels and does not support multitouch.…”

“…Traditional resistive and surface capacitive touch screens, as well as the aforementioned force touch panel [4], calculate the touch position by the ratios of values measured at the peripherals or corners of the touch screen. Since all the available data consists of only one x coordinate and one Y coordinate, it is not possible to detect more than one touch position.…”

Deformable single wall carbon nanotube electrode for transparent tactile touch screen

“…Touch force sensing is more intuitive and less cumbersome, since it enables paper-like hand-writing and drawing input, for example by modifying line width depending on the applied force. Several technologies have been proposed to achieve force-sensitive touch screens by using strain gauges or quantum tunnelling composite materials [1,2]. The position of touch can be determined by the ratios of force read from each of the four corners.…”

“…The fabricated capacitive tactile touch screen consists of a cross-array of rectangular transparent electrode patterns, where cross electrode area A is separated by distance D with silicone gel of relative dielectric constant 1 r . The capacitance between crossed electrodes is described by (1), where 1 0 is the permittivity of free space:…”

“…The gap between the flexible touched upper electrode and the lower electrode can be changed by an applied force, and hence the capacitance change is obtained with compressive-elastic deformation of the silicone gel. The theoretical capacitance was calculated using (1), where A is the crossed area (5 × 5 mm) between the electrodes in Fig. 4a, 1 r is 2.87 in Table 1 and D is the compressed thickness with applied force of 3-4154 silicone gel in Fig.…”