投射式電容式觸控面板電極圖騰之最佳化設計

Abstract

本論文目的為以有限元素分析軟體模擬投射電容式觸控面板，並利用最佳化方法改善其觸控靈敏度，使觸控面板讀取電路的設計更有效率。投射電容式觸控面板的觸控感應訊號主要來自手指靠近面板時造成電極互電容的微小變化。透過改變電極各部位的尺寸可以影響此微小電容變化的比例。本論文首先透過有限元素分析軟體COMSOL建立投射電容式觸控面板的模擬模型。此模型可針對不同電極圖騰設計的投射電容式觸控面板做調整，並提供數值化的電性模擬結果，提供觸控面板讀取電路的設計之重要依據，並幫助了解改變此圖騰各部位尺寸對於觸控感應訊號的影響。透過COMSOL建立的投射電容式觸控面板模擬模型可利用MATLAB改變模擬模型中的設計參數並進行有限元素模擬分析，評估出此面板設計的觸控效果表現。藉由此有限元素模擬模型之分析結果，本論文針對採用菱形做為電極圖騰形狀的投射電容式觸控面板整理出最佳化準則。最後，本論文分別針對不同觸控讀取電路設計成本的投射電容式觸控面板進行最佳化設計，並提供最佳靈敏度與充放電時間的權重關係，供投射電容式觸控面板模組的設計作為依據。另外，本論文中已建立的投射電容式觸控面板模擬模型也可與AMOLED顯示器整合，進行摺疊式觸控顯示面板的模擬分析。

This study proposes the optimal design for a projected capacitive touch panel. The panel consists of two parallel Indium Tin Oxide (ITO) film layers which are separated by a sensor glass layer. Our goal is to optimize the touch sensitivity for the projected capacitive touch panel, where capacitance shifts due to environmental disturbance are commonly presented to make successful touch detections difficult. A simulation model of projected capacitive touch panel is built by COMSOL. Numerical values of touch sensing signal of different touch panel design can be simulated by this model to provide a reference for touch panel controller design. Design guidelines of ITO electrode pattern are distilled herein to improve the detection sensitivity for projected capacitive touch panel. Also, the cost of designing the touch panel is optimized for super sensitivity. Finally, the relationship between the time constant and detection sensitivity has been studied to achieve balance in the design of the projected capacitive touch panel.