A touch panel, an input apparatus that allows a finger to move on a smooth panel to control a cursor, is frequently used with laptop computers, mobile phones, personal digital assistants (PDAs) and other electronic apparatus. Since a principle of the touch panel does not involve a mechanistic design that is applied to a mouse or a keyboard, it is rather simple to maintain the touch panel. As current electronic products are being developed to be more compact with better portability, the touch panel serving as an input apparatus is also becoming more popular.
For a touch panel, an electric signal is generated from sensing pressure on the touch panel touched by a finger or a conductivity change caused by a finger touch. Thus, a touch point sensed on the touch panel and a displacement of the touch point are influenced by a touch strength, a touched area, a hand tremor or a sensitivity of the touch panel. In addition, since a surge caused by electromagnetic interferences (EMI) may trigger the touch panel to detect an incorrect touch point, a misjudgment on the displacement of the touch point may also be concluded by the touch panel. For example, a part of certain sensors of the touch panel may be mistakenly determined as being touched since a voltage of those sensors is increased due to mobile phone electromagnetic waves, thus leading to a misjudgment concluded by the touch panel.
Therefore, a method for determining a touch point movement and an associated apparatus capable of reducing noise that interferes with determination of a displacement of a touch point are keys for increasing efficiency of applications of a touch panel.