Ghost cancellation method for multi-touch sensitive device
A ghost cancellation method for the multi-touch sensitive device is disclosed. The multi-touch sensitive device includes a sensing array having multiple lines of a first axis and multiple lines of a second axis intersecting with each other. All the lines of the sensing array are scanned to determine which ones of the lines are touched, so as to determine touch point candidates. For each touch point candidate, a driving signal is applied to the line of the first axis, and the line of the second axis is detected to check if the touch point candidate is actually touched.
1. A ghost cancellation method for the multi-touch sensitive device, the multi-touch sensitive device comprising a sensing array having multiple lines of a first axis and multiple lines of a second axis intersecting with each other, the method comprising the following sequential steps:
applying a driving signal to each line of the first axis;
detecting the driven line of the first axis to determine whether said line is touched or not;
applying a driving signal to each line of the second axis;
detecting the driven line of the second axis to determine whether said line is touched or not;
determining touch point candidates based on the touched lines of the first axis and the touched lines of the second axis;
applying a driving signal to the line of the first axis for each touch point candidate; and
detecting the line of the second axis for the touch point candidate to determine whether said touch point candidate is touched or not.
2. The method of claim 1 , wherein the touch point candidates are at intersections of the touched lines of the first axis and the touched lines of the second axis.
3. The method of claim 1 , wherein the first axis is X-axis and the second axis is Y-axis.
4. The method of claim 1 , wherein the first axis is Y-axis and the second axis is X-axis.
5. The method of claim 1 , wherein a plurality of lines of the first axis are applied with different driving signals at the same time in the step of applying a driving signal to the line of the first axis for each touch point candidate.
6. The method of claim 1 , wherein a plurality of lines of the second axis are detected at the same time in the step of detecting the line of the second axis for the touch point candidate.
7. The method of claim 6 , wherein the lines of the second axis for the touch point candidates on the same line of the first axis are detected at the same time.
8. The method of claim 1 , wherein a sensing signal with amplitude less than the driving signal is detected from the line of the first axis after the line is applied with the driving signal if said line is touched.
9. The method of claim 1 , wherein a sensing signal with amplitude less than the driving signal is detected from the line of the second axis after the line is applied with the driving signal if said line is touched.
10. The method of claim 1 , wherein a sensing signal is detected from the line of the second axis for the touch point candidate after the driving signal is applied to the line of the first axis for said touch point candidate if said touch point candidate is actually touched, while no sensing signal is detected from the line of the second axis for the touch point candidate after the driving signal is applied to the line of the first axis for said touch point candidate if said touch point candidate is not touched.
11. The method of claim 1 , wherein a plurality of lines of the first axis are applied with different driving signals at the same time in the step of applying a driving signal to each line of the first axis.
12. The method of claim 1 , wherein a plurality of lines of the second axis are applied with different driving signals at the same time in the step of applying a driving signal to each line of the second axis.
13. The method of claim 1 , wherein a plurality of lines of the first axis are detected at the same time in the step of detecting the driven line of the first axis to determine whether said line is touched or not.
14. The method of claim 1 , wherein a plurality of lines of the second axis are detected at the same time in the step of detecting the driven line of the second axis to determine whether said line is touched or not.