A review of technologies for sensing contact location on the surface of a display

Abstract

Touchscreen interactive devices have become increasingly important in both consumer and commercial applications. This paper provides a broad overview of all touchscreen technologies in use today, organized into 13 categories with 38 variations. The 13 categories are projected capacitive, analog resistive, surface capacitive, surface acoustic wave, infrared, camera‐based optical, liquid crystal display in‐cell, bending wave, force sensing, planar scatter detection, vision‐based, electromagnetic resonance, and combinations of technologies. The information provided on each touchscreen technology includes a little history, some basic theory of operation, the most common applications, the key advantages and disadvantages, a few current issues or trends, and the author's opinion of the future outlook for the technology. Because of its dominance, this paper begins with projected capacitive; more information is provided on this technology than on any of the other touch technologies that are discussed. This paper covers only technologies that operate by contact with a display screen; this excludes technologies such as 3D gesture recognition, touch on opaque devices such as interactive whiteboards, and proximity sensing. This is not a highly technical paper; it sacrifices depth of information on any one technology for breadth of information on multiple technologies.

Multi-touch Tabletop System Using Infrared Image Recognition for User Position Identification

“…These include projected capacitive, analog resistive, infrared, camerabased optical, planer scatter detection, vision-based, and combinations of technologies. Walker [5] presented a broad overview of 13 types of touchscreen technologies describing for each a brief history, basic operating principle, typical applications, main advantages and disadvantages, current issues and trends, and future outlook. He described the projected capacitive method in more detail than the other methods due to its current dominance.…”

“…There have been many research studies to date in relation to tabletop systems including touch screen technology [5], a method for achieving an interactive table [6], research on multi-touch gestures [7], [8], and application to collaborative work support [4], [9]. Among the methods used to achieve an interactive table, the frustrated total internal reflection (FTIR) method can obtain infrared images through a simple and inexpensive mechanism that irradiates the interior of an acrylic panel with infrared light and detects leaked light from the section of the panel touched by the user using an infrared camera [6].…”

Carbon nanotube based transparent conductive films: progress, challenges, and perspectives

“…A resistive touch panel contains several layers, the most important of which are two layers of TCFs separated by a thin space, while a capacitive touch panel contains an insulator and a layer of TCF. [122] Resistive touch panels usually need TCF with higher transmittance (>95%), while capacitive touch panels need TCF with smaller sheet resistance (<300 Ω/square). Touch panels have no special requirements for surface roughness or the work function of TCFs, and the requirement for sheet resistance is not strict.…”

A Wearable Textile 2D Touchpad Sensor Based on Screen-Printing Technology

“…From all of them, analog resistive and capacitive touch technologies dominate the touch landscape today [12]. Others have used optical sensing [13], force sensing [14], or even inductive sensing [15].…”