兼具觸控驅動與閘極驅動功能整合之顯示電路技術研究

Abstract

就目前的智慧型手機及平板電腦的市場，觸碰面板已經是現有的趨勢，而這樣的使用介面，因為使用上簡單、可節省傳統鍵盤的空間、更符合人們使用上的直觀感受，因此可預期的，未來將會逐步取代全面鍵盤介面，甚至更滲透於所有的中大型顯示器。而觸碰面板介面中，投射式電容因為具有穿透率高且輕碰即可反應的特性，目前也逐漸成為市場上的主流觸碰介面。但傳統的外嵌式(Out-Cell)結構當中，由於多了一塊觸碰面板，使得重量更重、模組更厚、價格更高、透光率也會下降。因此，後續才會有其他不同的結構例如將傳統的外嵌式的觸控部分完全整合成一片玻璃，又或者說把觸控的部分做在像是彩色濾光片的上面，我們則稱之為表嵌式(On-Cell)，若將觸控的部分做在液晶層，我們則稱之為(In-Cell)。而當我們致力於將觸控與顯示面板結合在一起，勢必就會遇到不可避免的銦錫氧化物電極共用問題。我們假設，在原本的銦錫氧化物電極上，當我們做到表嵌式或者內嵌式的狀況之下，位於彩色濾光片下層的銦錫氧化物電極層，需要同時接受由面板IC發出的電壓準位Vcom來維持液晶正反轉以及由觸碰IC所發出的Tx(Transmissive signal)來激發整個觸碰流程。因此，在整個訊號的整合或者取代的研究上都是未來很重要的研究主題。 在本篇論文當中，提出一個整合型的閘極驅動以及觸碰驅動電路，製作於薄膜電晶體陣列端。我們整合了之前取代閘極驅動IC的閘極驅動電路，並且再設計一個觸碰電路來與閘極驅動電路結合，使得我們只需要一個面板IC給訊號，就可以得到由閘極驅動電路的序列式波型，在由此波型來激發我們的觸碰驅動電路，進而得到觸碰激發訊號以及提供液晶正反轉的參考電壓。也就是說，原本需要由兩顆IC來發出的兩個驅動訊號，現在只需要一顆IC就可以達到。藉由此電路設計的可行性，我們希望可逐漸將觸控IC裡面的激發電路給取代至我們的薄膜電晶體陣列端，來達到降低成本、減少IC設計難度，並且逐漸的實現嵌入式觸控的目標。

Touch panel is the main stream interface as for present market in PDA (Personal Digital Assistant) and tablet computer. The interface has many advantages：easy-use、saving space compared to conventional keyboard、fitter with the people’s habit. We can predict that touch panel interface will totally replace keyboard interface, and even permeate into middle and high size display screen. Among all touch panel interfaces, projected capacitive technology gradually becomes the main stream one in the market. However, in the structure of the traditional style out-cell, since it is combined with the LCD so the touch screen is getting heavier, thicker, higher cost and worse optical performances because of extra touch panel glass. Therefore, how to integrate LCD panel and touch panel is that the panel manufacturer devoted to developing all the time. Once we put the touch panel on the color filter, it is called the on-cell structure. Otherwise, while the touch panel placed during the liquid crystal, it is called the in-cell structure. However, when we work for integrating the touch panel and LCD, the ITO shared problem will come out. For example, during the in-cell structure, the ITO electrode beyond the color filter need to accept the signals both from display IC for polarity inversion Vcom and touch IC for stimulation signal Tx (Transmissive signal). In a word, the on-cell or in-cell structure accompanies the IC integrating or replacing issues. In this thesis, we propose the integration circuit with touch driver on array (TOA) and gate driver on array (GOA). Since the driver IC for turning on pixel was replaced by the gate driver, we use the output of the GOA to design a circuit for the touch flow and polarity inversion. That’s the purpose of TOA. The advantage is that we need only one display IC then we can generate two signals which are outputted by two ICs in the traditional way. By the design of TOA, we hope to replace the stimulation circuit from touch IC to LCD array and achieve the purpose of low cost、decrease the difficulty of IC design and implement the objective of in-cell integration step by step.