Anisotropic touchscreen

摘要

A method for detecting a touch spot of the touch panel includes the following steps. The electrode pairs are scanned along the impedance direction to obtain an electrical signal curve for determining a first coordinate. A number of first driving electrodes and a number of second driving electrodes near the first coordinate are selected. The selected first driving electrodes are scanned to obtain a first sensing signal. The selected second driving electrodes are scanned to obtain a second sensing signal. A second coordinate is determined according to the first and second sensing signals. Finally, the touch spot is determined according to the first and second coordinates.

主权项

1. A method for detecting a touch spot of a touch panel, the touch panel comprising a substrate, a plurality of first driving electrodes, a plurality of second driving electrodes, and a conductive film disposed on the substrate, the conductive film comprising a first side and a second side, and defining a first impedance direction and a second impedance direction substantially perpendicular to the first impedance direction, the first side and the second side being substantially parallel to the first impedance direction, the plurality of first driving electrodes being disposed at the first side with a regular interval and electrically connected to the conductive film, the plurality of second driving electrodes being disposed at the second side with a regular interval and electrically connected to the conductive film, the plurality of first driving electrodes are respectively aligned with the plurality of second driving electrodes to form a plurality of electrode pairs, the method comprising:
inputting a pulse signal into each of the plurality of electrode pairs via at least one driving circuit; detecting a plurality of sensing signals from the plurality of electrode pairs via at least one sensing circuit to obtain an electrical signal curve, wherein the electrical signal curve is a resistor-capacitor signal curve comprising a plurality of resistor-capacitor values represented by RnC; determining a first coordinate according to the electrical signal curve by detecting a smallest resistor-capacitor value at the resistor-capacitor signal curve using:
a first formulaXX⁢Δ⁢⁢RX⁢C+Xy⁢Δ⁢⁢Ry⁢CΔ⁢⁢RX⁢C+Δ⁢⁢Ry⁢C, wherein ΔRXC=RkC−RXC and ΔRyc=RkC−RyC, when RxC is equal to RyC;a second formulaXZ⁢Δ⁢⁢RZ⁢C+Xy⁢Δ⁢⁢Ry⁢CΔ⁢⁢RZ⁢C+Δ⁢⁢Ry⁢C, wherein ΔRyC=RkC−RyC and ΔRZC=RkC−RZC, when RxC is different from RyC, and RyC is equal to RZC;a third formulaXX⁢Δ⁢⁢RX⁢C+Xy⁢Δ⁢⁢Ry⁢C+XZ⁢Δ⁢⁢RZ⁢CΔ⁢⁢RX⁢C+Δ⁢⁢Ry⁢C+Δ⁢⁢RZ⁢C, wherein ΔRXC=RkC−RXC, ΔRyC=RkC−RyC, and ΔRZC=RkC−RZC; ora fourth formula∑n=1E⁢Xn⁢Δ⁢⁢Rn⁢C∑n=1E⁢Δ⁢⁢Rn⁢C, wherein ΔRnC=RkC−RnC, E is a total number of the plurality of electrode pairs, RXC is a smallest resistor-capacitor value, RyC is a second small resistor-capacitor value, RZC is a third small resistor-capacitor value, and RkC is a greatest resistor-capacitor value of the resistor-capacitor signal curve; selecting a part of the plurality of first driving electrodes near the first coordinate and inputting a pulse signal into the part of the plurality of first driving electrodes simultaneously via the at least one driving circuit; detecting a first sensing signal from the part of the plurality of first driving electrodes via the at least one sensing circuit; wherein the first sensing signal is a product of a first resistance value multiplied by a first capacitance value, the first resistance value is a total resistance of a plurality of resistances parallel connected to each other, and the plurality resistances are resistances between the touch spot and each of the part of the plurality of first driving electrodes; selecting a part of the plurality of second driving electrodes near the first coordinate and inputting a pulse signal into the part of the plurality of second driving electrodes simultaneously via the at least one driving circuit; detecting a second sensing signal from the part of the plurality of second driving electrodes via the at least one sensing circuit; wherein the second sensing signal is a product of a second resistance value multiplied by a second capacitance value, the second resistance value is a total resistance of a plurality of resistances parallel connected to each other, and the plurality resistances are resistances between the touch spot and each of the part of the plurality of first driving electrodes; determining a second coordinate according to the first sensing signal and the second sensing signal comprising:
computing a ratio of the first sensing signal to the second sensing signal; anddetermining the second coordinate according to the ratio of the first sensing signal to the second sensing signal, wherein the ratio of the first sensing signal to the second sensing signal is proportional to a ratio of a distance between the second coordinate and the first side to a distance between the second coordinate and the second side; and determining the touch spot according to the first coordinate and the second coordinate.