光感應式觸控面板系統

Abstract

內嵌式觸控面板 ─ Touch Panel Integration On Glass為目前顯示技術的一種新提案。其製作方法是在薄膜電晶體畫素陣列中新增光感應式元件的構造，將觸控面板機能整合進入15吋非晶矽薄膜電晶體液晶面板中，讓顯示面板具備能使用光筆輸入顯示或利用手指遮斷輸入顯示觸控面板功能的特性。在每四條gate lines與每四條data lines 之影像畫素中埋入光感測元件即可使一解析度為XGA 1024x768的15吋LCD面板其感測器解析度達到256x192。利用手指阻斷環境光或利用光筆打點使強光打在觸控面板上便能使觸控面板產生動作。當用手指阻斷環境光時，會有一類比訊號輸出，由類比數位轉換器將類比訊號轉換為電腦可以接受的數位訊號，再經由FPGA提供時序給類比板，透過SPI介面到C8051，最後由USB傳送到PC由電腦裡的觸控驅動程式整合各元件編譯並作演算法，即可在螢幕上顯示出使用者所觸碰的位置。光感應式觸控面板其最大的優點為降低成本、改善光穿透效率、耐用、厚度減薄，並改善電容式需多點校正的問題。

Touch Panel Integration on Glass is a new proposal for recent display technology. The way to produce is to add photo-sensor structure in TFT Pixel Array, then to integrate touch panel function into 15 inch a-Si TFT-LCD panel, and to enable the display panel with Light-Pen Input Display or Finger Sensing Input Display function. We embedded a-Si photo sensors every 4 lines of gate lines and data lines into 15 inch LCD panel with resolution of XGA 1024x768 to let the sensor line resolution to reach 256x192. Either use fingers to block the light or use the light pen to put the strong light on the touch panel, we allow the touch panel create movements. When use fingers to block the ambient light it will have analog signal output, then through ADC to transfer analog signal to digital signal which is acceptable by computers. FPGA provides timing chart to analog board, through SPI interface to C8051, then through USB convey to PC, and the software touch control drivers in the computer will integrate all the components and edit them to calculate, finally show the position that users been touched on the screen. The biggest advantage of photo-sensor touch panel is to lower the cost, improve the transmittance, long lasting, reduce the thickness, and improve the calibration problems of capacitive touch panel.