A 55dB SNR with 240Hz frame scan rate mutual capacitor 30×24 touch-screen panel read-out IC using code-division multiple sensing technique
A 55dB SNR with 240Hz frame scan rate mutual capacitor 30×24 touch-screen panel read-out IC using code-division multiple sensing technique
复制标题
采用码分多重传感技术、55dB SNR、240Hz 帧扫描速率互电容 30×24 触摸屏面板读出 IC
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Kwyro Lee
中科院分区：
文献类型：
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作者：
Hyungcheol Shin;Seunghoon Ko;Hongjae Jang;Ilhyun Yun;Kwyro Lee
电容式触摸屏技术为用户界面引入了新的概念，例如多点触摸、捏放大/缩小手势，从而扩大了智能手机市场。然而，电容式触摸屏技术仍然遭受性能下降，如低帧扫描速率和差的准确性，等等。关键性能因素之一是对随机侵入触摸屏系统的外部噪声的免疫力。HUM、显示器噪声和SMPS是这样的噪声源。主电源产生HUM，这是最重要的噪声源之一，具有50或60 Hz的分量。当LCD或OLED由内部时序控制器驱动时，会发出显示噪声，内部时序控制器会产生数十kHz范围内的驱动信号。On-Cell或In-Cell触摸显示器的触摸性能受到这种噪声的严重影响，因为显示像素层与电容式触摸屏面板之间的距离越来越小。SMPS是另一个噪声源，范围高达300 kHz。智能手机的充电器、计算机中的USB端口、三磷光体荧光灯泡都是SMPS源的示例。已经有许多尝试来消除这种噪音。在文献[1]中提出了跳频调幅。然而，当噪声环境改变时，该方法需要重新校准，导致非恒定的触摸响应时间。另一种方法试图过滤显示器的噪声[2]，但它不能去除其他噪声源，如HUM或SMPS。
Capacitive touch-screen technology introduces new concepts to user interfaces, such as multi-touch, pinch zoom-in/out gestures, thus expanding the smartphone market. However, capacitive touch-screen technology still suffers from performance degradation like a low frame scan rate and poor accuracy, etc. One of the key performance factors is the immunity to external noise, which intrudes randomly into the touch-screen system. HUM, display noise, and SMPS are such noise sources. The main electrical power source produces HUM, one of the most important sources of noise, which has a 50 or 60Hz component. Display noise is emitted when an LCD or OLED is driven by the internal timing controller, which generates the driving signal in the tens of kHz range. The touch performance of On-Cell or In-Cell touch displays is seriously affected by this kind of noise, because the distance between the display pixel layer and the capacitive touchscreen panel is getting smaller. SMPS is another noise source that ranges up to 300kHz. The charger for a smart-phone, the USB port in a computer, a tri-phosphor fluorescent light bulb are all examples of sources of SMPS. There have been many attempts to remove such noise. Amplitude modulation with frequency hopping is proposed in [1]. However, when the noise environment changes, this method needs recalibration, resulting in non-constant touch response time. Another method tries to filter the noise from the display [2], but it does not remove other noise sources like HUM or SMPS.