利用雙閘極氧化銦鎵鋅薄膜電晶體實現主動式觸控偵測電路之研究

Abstract

利用所提出的雙閘極氧化銦鎵鋅薄膜電晶體(IGZO TFT)於主動式矩陣觸碰感測電路與RC低通濾波器。由於雙閘極氧化銦鎵鋅薄膜電晶體可藉由其上閘極與下閘極所控制，所提出的電路只需要一個薄膜電晶體即可，如此可擴展感測畫素的開口率。藉由觸摸事件所導致RC時間常數的增加，一個明顯的瞬態導通電流出現，可作為感測訊號。這個信號可以很容易地被讀出，從而減少外圍 IC的成本。此外該傳感器消耗較少的待命功率，因為當它沒有被觸及時，沒有信號電流發生。在這樣的設計下，使得以往的觸摸感應技術的缺點有相當大的改進。因此，我們相信所提出的感測電路可能是一個很好的方法來實現主動式矩陣觸摸面板。

The dual gate IGZO TFT is proposed to be used in an active matrix touch sensing circuit with a RC low-pass filter. Since the dual gate IGZO TFT can be controlled by both its top and bottom gates, only one TFT is needed in the proposed circuit, which enlarges the open ratio of sensing pixel. By a touch event which increases the RC time-constant, a significant transient ON current is generated to be the sensing signal. This signal can be easily read out and thus reduce the cost of peripheral ICs. In addition, this sensor consumes less standby power because no signal current occurs if it is not touched. In such design, it makes considerable improvement over the drawbacks of previous touch sensing technology. Thus, we believe the proposed sensing circuit could be an excellent way to implement active matrix touch panels.