Capacitive position sensor system
First Claim
1. A capacitive position sensor system for determining the position of an object, wherein the object is positioned within a sensitive area of the capacitive position sensor system and changes the capacitance of capacitors being arranged underneath the object, the capacitive position sensor system comprisinga first plurality of sensing elements, each sensing element comprising a first capacitor having a first electrode and a second electrode, wherein each first electrode is coupled via a switch to a voltage supply to form a switched capacitor filter, wherein the switch for each first capacitor is located between the voltage supply and the first electrode of each first capacitor, and wherein the second electrodes are coupled to form a sensing line,a sensing unit, wherein the sensing unit is adapted to sense a voltage level representing the amount of charge being present on the sensing line, anda control unit, wherein the control unit is adapted to apply a drive signal to each of the switches being coupled to the first electrodes,wherein, in one integration cycle, a part of the switches being coupled to the first electrodes is closed so that a part of the first capacitors is driven by a first drive signal, wherein the sensing unit is adapted to sense the voltage level representing the sum of the amount of charge of the part of the first capacitors, wherein the number of the switches being closed is at least two,wherein the control unit is adapted to determine the position of the object by analyzing the results of a plurality of sensed voltage levels of a plurality of integration cycles.
10 Assignments
0 Petitions
Accused Products
Abstract
A capacitive position sensor system is provided for determining the position of an object, wherein the object is positioned within a sensitive area of the capacitive position sensor system and changes the capacitance of capacitors being arranged underneath the object.
-
Citations
18 Claims
-
1. A capacitive position sensor system for determining the position of an object, wherein the object is positioned within a sensitive area of the capacitive position sensor system and changes the capacitance of capacitors being arranged underneath the object, the capacitive position sensor system comprising
a first plurality of sensing elements, each sensing element comprising a first capacitor having a first electrode and a second electrode, wherein each first electrode is coupled via a switch to a voltage supply to form a switched capacitor filter, wherein the switch for each first capacitor is located between the voltage supply and the first electrode of each first capacitor, and wherein the second electrodes are coupled to form a sensing line, a sensing unit, wherein the sensing unit is adapted to sense a voltage level representing the amount of charge being present on the sensing line, and a control unit, wherein the control unit is adapted to apply a drive signal to each of the switches being coupled to the first electrodes, wherein, in one integration cycle, a part of the switches being coupled to the first electrodes is closed so that a part of the first capacitors is driven by a first drive signal, wherein the sensing unit is adapted to sense the voltage level representing the sum of the amount of charge of the part of the first capacitors, wherein the number of the switches being closed is at least two, wherein the control unit is adapted to determine the position of the object by analyzing the results of a plurality of sensed voltage levels of a plurality of integration cycles.
-
15. A method of determining the position of an object, wherein the object is positioned within a sensitive area of the capacitive position sensor system and changes the capacitance of capacitors being arranged underneath the object, wherein the capacitive position sensor system comprises a first plurality of sensing elements, each sensing element comprising a first capacitor having a first electrode and a second electrode, wherein each first electrode is coupled via a switch to a voltage supply to form a switched capacitor filter, wherein the switch for each first capacitor is located between the voltage supply and the first electrode of each first capacitor, and wherein the second electrodes are coupled to form a sensing line,
the method comprising sensing, by a sensing unit, a voltage level representing the amount of charge being present on the sensing line, applying, by a control unit, a drive signal to each of the switches being coupled to the first electrodes, wherein, in one integration cycle, a part of the switches being coupled to the first electrodes is closed so that a part of the first capacitors is driven by a first drive signal, wherein the sensing unit is adapted to sense the voltage level representing the sum of the amount of charge of the part of the first capacitors, wherein the number of the switches being closed is at least two, determining, by the control unit, the position of the object by analyzing the results of a plurality of sensed voltage levels of a plurality of integration cycles.
-
16. A capacitive position sensor system for determining the position of an object, wherein the object is positioned within a sensitive area of the capacitive position sensor system and changes the capacitance of capacitors being arranged underneath the object, the capacitive position sensor system comprising
a first plurality of sensing elements, each sensing element comprising a first capacitor having a first electrode and a second electrode, wherein each first electrode is coupled via a switch to a voltage supply to form a switched capacitor filter, wherein the second electrodes are coupled to form a sensing line, a sensing unit, wherein the sensing unit is adapted to sense a voltage level representing the amount of charge being present on the sensing line, and a control unit, wherein the control unit is adapted to apply a drive signal to each of the switches being coupled to the first electrodes, wherein, in one integration cycle, a part of the switches being coupled to the first electrodes is closed so that a part of the first capacitors is driven by a first drive signal, wherein the sensing unit is adapted to sense the voltage level representing the sum of the amount of charge of the part of the first capacitors, wherein the number of the switches being closed is at least two, wherein the control unit is adapted to determine the position of the object by analyzing the results of a plurality of sensed voltage levels of a plurality of integration cycles, wherein each sensing element of the first plurality of sensing elements comprises a second capacitor having a first electrode and a second electrode, wherein each first electrode is coupled via a switch to the voltage supply to form a switched capacitor filter, wherein the second electrodes are coupled to form a further sensing line, wherein a specific weighting factor is assigned to each capacitor, wherein the capacitances of the first and the second capacitor of one sensing element corresponds to a constant capacitance value, wherein, in one integration cycle, a part of the switches being coupled to the second electrodes is closed so that a part of the second capacitors is driven by a second drive signal, wherein the sensing unit is adapted to sense the voltage level representing the sum of the amount of charge of the part of the first capacitors and the voltage level representing the sum of the amount of charge of the part of the second capacitors, wherein the control unit is adapted to determine the position of the object by analyzing the results of a plurality of sensed voltage levels for the first capacitors and the second capacitors of a plurality of integration cycles.
Specification