Noise Reduction and Accuracy Enhancement of Projected Capacitive Touch Panel Technology
Date Issued
2014
Date
2014
Author(s)
Chang, Hung-Hsien
Abstract
When we use the projected capacitive touch panel, the panel suffer from noise effect. The noise effect cause the inaccuracy and instability of the computed position. As the size of touch panel become larger and larger, the problem from noise become worse and worse. Besides, the coupling effect between human body and panel will cause inversion situation. The inversion situation will make the panel compute a wrong position. The accuracy on the border of the panel is another problem on the touch panel. We need to compute an accurate touch position without full information. There are two parts in this thesis: noise reduction and accuracy enhancement. According to the architecture of touch panel, low frequency noise effect cannot be removed completely. We proposed a new method to reduce the low frequency noise by dividing and grouping. The original method to compute a touch position is the center-of-gravity method. However, inversion situation cannot select the main touch sensor correctly. We proposed a voting method to decide the main touch sensor. Besides, because of lacking information of touch sensors, we also proposed some methods such as extension method and comparison method to resolve the problem on the border case. Last but not least, an automatic test environment was established by computer numerical control system. The test environment not only reduced the time of test but enhanced the accuracy during the operation.
Subjects
Projected capacitive touch panel
Noise reduction
Accuracy enhancement
Voting method
Extension method
Computer numerical control system
Type
thesis
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