26.2 Virtual Rotating Gesture Recognizable Touch Readout IC for 1.26” Circular Touch Screen Panel

Abstract

Recently, there have been many advances in user interaction systems in mobile devices. In addition to traditional capacitive touch systems, a stylus is becoming mainstream, which is a very useful feature for large-sized tablet PCs [1]. However, wearable devices, which are composed of inevitably small display panels, need a new interaction system for improved convenience. This paper presents a virtual rotating gesture-recognition IC (VRGR-IC) on a bezel area for a wearable device employing a circular display. For an implementation of the VRGR, the sensors should be placed below the bezel. However, the bracket to assemble the display and main body of a wearable device makes it unable to place any sensors in that position, as shown in the top of Fig. 26.2.1. To alternatively implement that function, two key features of this work include: 1) an integrated capacitive touch and VRGR system, which enables traditional 2-D touch sensing on a display's active area and near-field 3-D hover gesture on the bezel area, and 2) a haptic generating system, which provides continual haptic feedback responsive to a finger rotation. More specifically, the bottom of Fig. 26.2.1 shows the operational principle of the VRGR system, which incorporates a touch-screen panel (TSP), VRGR-IC, AMOLED display, display driver IC (DDl), application processor (AP), and linear resonant actuator (LRA). When the TSP is touched, the VRGR IC extracts both the touch coordinates <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$(\mathsf{x}_{1},\mathsf{y}_{1})\sim (\mathsf{x}_{\mathsf{n}},\mathsf{y}_{\mathsf{n}})$</tex> of multi-finger as well as an angle of rotation on a bezel by a finger. Those are sent to the AP, which sends back the haptic generation requests to the VRGR IC when a rotated angle is reached to a reference <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\theta_{\mathsf{R}}$</tex> . Simultaneously, a newly updated graphic userinterface according to the gesture recognition is displayed in the AMOLED panel by the DDl.