Study On Sensitivity Of The Projected Capacitive Touch Panel

In recent years,the projected capacitive panel has showed its comprehensive advantages in durability,optical clarity,multi-touch and other aspects,for which it has been the main stream technology in the touch panel Market.However,the projected capacitive touch panel needs to detect small to several fF capacitance changes in some cases,these tiny signals are easily covered by various noise interferences in the working environment,which makes it difficult to identify the touch physical signals,and may even cause the capacitance touch panel not work normally.Therefore,it is important to develop touch panel with high sensitivity.This paper introduces the basic structure of the touch panel,stack of various types and the traditional double ITO pattern and single ITO design,which will play a certain guiding role in the design of the touch panel.The touch panel is equated to an circuit that contains a variety of capacitances.The finite element simulation is carried out by using the physical knowledge of the electromagnetic field and the electrode simulation theory of the touch panel sensor,which is used to study the common stack models and typical sensor pattern designs.Simulation produces a capacitance matrix,from which the key parameters of the sensor performance such as sensitivity and signal-to-noise ratio are derived.This paper mainly discusses the following two aspects:1?In order to improve the sensitivity of the touch panel in optimizing the structure of capacitive panel,this paper studies the geometric parameters size on the influence of mutual capacitance change and signal-to-noise ratio by altering three size types of electrodes: Pitch,Deletion and Bridge Width,and then draws a close relationship between the touch panel layout and its performance.The research method is convenient for developers to understand the influence of the structure of capacitive touch panel on the sensitivity.2?In order to improve the sensitivity of the touch panel from the design of the electrode pattern,the finite element analysis theory is used to simulate and analyze some common electrode patterns in this paper.Based on this analysis,several types of touch panel electrodes are designed,and the relationship between the electrode pattern and sensitivity is verified by the simulation of the touch panel with different electrodes.The research result shows that increasing the edge area can improve sensitivity and the high sensitivity area.The research result has important application value for the design of high sensitivity touch panel.