Pressure-sensitive touch panel
A device ( 48 ) for combined capacitance and pressure measurements includes a number of first input/output terminals for a projected capacitance touch panel, wherein the projected capacitance touch panel includes a layer of piezoelectric material disposed between a plurality of first electrodes and at least one second electrode. The device also includes a plurality of second input/output terminals for a capacitive touch controller. The device also includes a plurality of separation stages, each separation stage connecting at least one first input/output terminal to a corresponding second input/output terminal, and each separation stage including a first frequency-dependent filter for filtering signals between first and second input/output terminals. The device also includes at least one amplification stage, each amplification stage having at least one input and an output configured to provide an amplified signal, wherein the number of amplification stages is less than or equal to the number of separation stages and each amplification stage input is connected to one or more of the first input/output terminals through the respective separation stage(s). Each amplification stage or each separation stage includes a second frequency-dependent filter for filtering signals between the respective first input/output terminal and an amplification stage input. Each first frequency-dependent filter is configured to pass signals to and/or from the capacitive touch controller and each second frequency-dependent filter is configured to attenuate signals from the capacitive touch controller.
1. An apparatus comprising:
a touchscreen panel comprising:
a plurality of first sensing electrodes disposed on a first face of a layer structure, the layer structure comprising at least a layer of piezoelectric material;
a plurality of second sensing electrodes disposed on a second face of the layer structure, the second face opposed to the first face;
a plurality of separated common electrodes disposed on the second face of the layer structure and interleaved with the second sensing electrodes; and
a device connected to the touchscreen panel and further configured for connection to a capacitive touch controller wherein the capacitive touch controller is configured to measure mutual capacitance between the first sensing electrodes and the second sensing electrodes;
the device comprising:
a plurality of input/output terminals for the capacitive touch controller;
a plurality of separation stages, each separation stage connecting a corresponding input/output terminal to at least one first sensing electrode or at least one second sensing electrode, wherein each separation stage is configured to pass signals to and/or from the capacitive touch controller;
at least one amplification stage, each amplification stage having at least one input and an output configured to provide an amplified signal, wherein the number of amplification stages is less than or equal to the number of separation stages and each amplification stage input is connected to one or more of the first input/output terminals through at least one respective separation stage;
wherein each amplification stage or each separation stage is configured to attenuate signals from the capacitive touch controller;
wherein the apparatus is configured to measure, based on the amplified signals, pressure values between the first sensing electrodes and the separated common electrodes.
2. The apparatus according to claim 1 , wherein each pressure value corresponds to a group of two or more first electrodes, and is indicative of a pressure applied to the touchscreen proximate to that group of first electrodes.
3. The apparatus according to claim 1 , further comprising a pressure signal processing module configured to:
receive one or more amplified signals; and
the pressure values in dependence upon the one or more amplified signals.
4. A touchscreen system comprising:
the apparatus according to claim 1 ; and
a capacitive touch controller connected to the device.
5. The apparatus according to claim 1 , wherein the plurality of separated common electrodes are coupled to each another and addressed collectively;
wherein each measured pressure value corresponds to a pressure value obtained between one of the first sensing electrodes and the separated common electrodes.
6. The apparatus according to claim 1 , wherein the plurality of separated common electrodes are individually addressable;
wherein each measured pressure value corresponds to a pressure value obtained between a pair of first and separated common electrodes.
7. An apparatus comprising:
a touchscreen comprising:
a plurality of first sensing electrodes disposed on a first face of a layer structure, the layer structure comprising at least a layer of piezoelectric material;
a plurality of second sensing electrodes disposed on a second face of the layer structure, the second face opposed to the first face;
a plurality of separated common electrodes disposed on the second face of the layer structure and interleaved with the second sensing electrodes; and
a device connected to the touchscreen panel, the device comprising:
a capacitive touch controller configured to measure mutual capacitances between the first sensing electrodes and the second sensing electrodes:
a plurality of input/output terminals connected to the capacitive touch controller;
a plurality of separation stages, each separation stage connecting a corresponding input/output terminal to at least one first sensing electrode or at least one second sensing electrode, wherein each separation stage is configured to pass signals to and/or from the capacitive touch controller;
at least one amplification stage, each amplification stage having at least one input and an output configured to provide an amplified signal, wherein the number of amplification stages is less than or equal to the number of separation stages and each amplification stage input is connected to one or more of the first input/output terminals through at least one respective separation stage;
wherein each amplification stage or each separation stage is configured to attenuate signals from the capacitive touch controller;
wherein the device is configured to measure, based on the amplified signals, pressure values between the first sensing electrodes and the separated common electrodes.
8. The apparatus according to claim 7 , wherein each pressure value corresponds to a group of two or more first electrodes and is indicative of a pressure applied to the touchscreen proximate to that group of first electrodes.
9. The apparatus according to claim 7 , further comprising a pressure signal processing module configured to:
receive one or more amplified signals;
calculate the pressure values in dependence upon the one or more amplified signals.
10. The apparatus according to claim 7 , wherein the plurality of separated common electrodes are coupled to each another and addressed collectively;
wherein each measured pressure value corresponds to a pressure value obtained between one of the first sensing electrodes and the separated common electrodes.
11. The apparatus according to claim 7 , wherein the plurality of separated common electrodes are individually addressable;
wherein each measured pressure value corresponds to a pressure value obtained between a pair of first and separated common electrodes.
12. A method of using a touchscreen and a capacitive touch controller, wherein the touchscreen comprises a plurality of first sensing electrodes disposed on a first face of a layer structure including at least a layer of piezoelectric material, a plurality of second sensing electrodes disposed on a second face of the layer structure, wherein the second face is opposed to the first face, and a plurality of separated common electrodes disposed on the second face of the layer structure and interleaved with the second sensing electrodes;
the method comprising:
using the capacitive touch controller to measure mutual capacitance values between the first electrodes and the second sensing electrodes, via a plurality of separation stages, each separation stage connecting a corresponding input/output terminal to at least one first sensing electrode or at least one second sensing electrode, wherein each separation stage is configured to pass signals to and/or from the capacitive touch controller;
measuring, based on amplified signals output from at least one amplification stage, pressure values between the first sensing electrodes and the separated common electrodes
wherein each amplification stage has at least one input and an output configured to provide a corresponding amplified signal, wherein the number of amplification stages is less than or equal to the number of separation stages and each amplification stage input is connected to one or more of the first input/output terminals through at least one respective separation stage, and wherein each amplification stage or each separation stare is configured to attenuate signals from the capacitive touch controller.
13. The method according to claim 12 , wherein each pressure value corresponds to a group of two or more first electrodes, and is indicative of a pressure applied to the touchscreen proximate to that group of first electrodes.