Pen pressure sensitive capacitive touch system and two-dimensional inductive power transfer system using resonance

Abstract

In Chapter 1, a touch system sensing passive stylus with pen pressure is implemented, which replace costly electro magnetic resonance (EMR) system with existing capacitive touch system for finger touch. The proposed system detects the location of stylus based on mutual-cap sensing, with finger, and senses pen pressure using well-defined process and sensor with designed resonant passive stylus pen. For mutual-cap sensing, to measure even small signal-cap for stylus, a multiple driving and sensing scheme is proposed with modified Hadamard matrix, resulting in highly increased dynamic range and SNR. In the proposed process for pen pressure sensing, the resonant frequency of passive resonant stylus is measured by high resolution frequency sensor, to achieve fine pen pressure sensing. The measured SNR for stylus location is 49 dB with $1mm \box$, and 6-bit resolution is achieved for pen pressure sensing.

In Chapter 2, The IPTS for mobile robots which has the single wire layer of easily fabricable power floor structure and the evenly displaced multi pick-up structure for receiving uniform power is proposed. Due to its simple structure, a wide area power floor of $3.52 m^2 (1.6 m \times 2.2 m)$ could be fabricated as a proto type. Three pick-ups with evenly displaced angle and space are adopted considering the limited bottom area of the free moving mobile robot. The size and position of each pick-up are appropriately selected for the given sub winding size of the power floor and magnetic pole arrangement. Experiments for the prototype show that the proposed multi pick-up structure lowers the spatial output power variation and that enough output power of 10 W can be obtained for the mobile robots.