60.3L: Late‐News Paper: Algorithm for Recognizing Pinch Gestures on Surface‐Capacitive Touch Screens

Abstract

Pinch gestures for scaling an image were recognized successfully on a surface-capacitive touch screen that has only a single-touch function without increasing manufacturing cost. An algorithm for recognizing the gestures was developed, which calculates the distance between two touching points without detecting each position of the two points. Author KeywordsSurface-capacitive touch screen; pinch gesture; touch position; simple structure; low cost J J J J J J J J d d d d d    (2) (a) Single-point touch (b) Two-point touch Figure 2. Touch images and current outputs

Recent Advances in Touch Sensors for Flexible Displays

“…The relationship between the supplementary current and the distances can be expressed as: IA / L1 = ID / L2 and ID / L3 = IC / L4, where L1 and L2 are the distance between the touch point and corners A and D in the horizontal direction, respectively; while L3 and L4 are the distances between the touch point and corners D and C in the vertical direction, respectively. IA, ID, and IC represent the supplementary current from corners A, D, and C. The coordinates of the contact point can be determined by L1 -L4 [17]. Surface capacitive touch sensors have several advantages over conventional resistive touch sensors, including hard surface, high sensitivity, extended lifetime, and high optical transmittance.…”

Review of Capacitive Touchscreen Technologies: Overview, Research Trends, and Machine Learning Approaches

“…The capacitive scheme is divided into surface-capacitive [ 81 , 83 ] and projected-capacitive methods [ 82 , 84 ]. Surface-capacitive touchscreens consist of one conductive layer of which four corners are connected to four perfectly synchronized alternative current (AC) voltage signals as described in Figure 3 .…”

“…Touchscreen technologies can be categorized into finger-touch and stylus-touch methods. While finger-touch methods include resistive, capacitive, acoustic wave, and optical approaches [ 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 , 94 , 95 , 96 , 97 , 98 , 99 , 100 , 101 ], stylus-touch ones cover up to electromagnetic resonance (EMR) schemes including finger-touch methodologies [ 102 , 103 , 104 , 105 , 106 , 107 , 108 ]. Recently, as wearable devices such as smartwatches and smartbands are becoming more popular, small-size displays are becoming further widespread with touch sensing functionality.…”