Sensor design for NFC-integrated touchpad
View Patent ↗An input device includes a plurality of sensor electrodes, an antenna, and a shield trace disposed between at least some of the sensor electrodes and the antenna. The antenna may be coupled to a transceiver and may transmit and receive radio-frequency (RF) communication signals. The shield trace may reduce, at least in part, coupling of the RF communication signals from the antenna to the sensor electrodes. The plurality of sensor electrodes may determine a presence, and/or a motion associated with an input object.
1. An input device comprising:
an input surface having a sensing region;
a plurality of sensor electrodes disposed beneath the input surface and configured to detect an input object in the sensing region, wherein the plurality of sensor electrodes includes at least a first electrode and a second electrode;
an antenna disposed beneath the input surface and the plurality of sensor electrodes, the antenna being configured to transmit and receive radio-frequency (RF) communication signals; and
a shield trace disposed between the plurality of sensor electrodes and the antenna, wherein the shield trace encompasses a first region in which the first electrode overlaps the antenna and is absent from a second region, different than the first region, in which the second electrode overlaps the antenna.
2. The input device of claim 1 , wherein the shield trace encompasses the first electrode.
3. The input device of claim 1 , wherein the first electrode is a receiver sensor electrode and the second electrode is a transmitter sensor electrode.
4. The input device of claim 1 , wherein the shield trace is wider than the first electrode.
5. The input device of claim 1 , wherein a width of the shield trace is less than or equal to 200 percent of a width of the first electrode.
6. The input device of claim 1 , wherein a width of the shield trace is greater than or equal to 150 percent of a width of the first electrode.
7. The input device of claim 1 , wherein the plurality of sensor electrodes is configured to detect the input object based on a capacitive coupling between the first electrode and the second electrode.
8. The input device of claim 1 , wherein an open area ratio associated with an area occupied by the plurality of sensor electrodes and the shield trace is greater than or equal to 40 percent.
9. The input device of claim 1 , wherein an open area ratio associated with an area occupied by the plurality of sensor electrodes and the shield trace is less than or equal to 50 percent.
10. The input device of claim 1 , wherein the second electrode has a wider trace width than the first electrode.
11. The input device of claim 1 , wherein the shield trace is coupled to a low impedance reference voltage.
12. The input device of claim 1 , wherein the antenna is configured to transmit and receive near field communication (NFC) signals.
13. An electronic system comprising:
a transceiver configured to transmit and receive radio-frequency (RF) communication signals; and
an input device comprising:
an input surface having a sensing region;
a plurality of sensor electrodes disposed beneath the input surface and configured to detect an input object in the sensing region, wherein the plurality of sensor electrodes includes at least a first electrode and a second electrode;
an antenna disposed beneath the input surface and the plurality of sensor electrodes, the antenna being configured to transmit RF communication signals from the transceiver; and
a shield trace disposed between the plurality of sensor electrodes and the antenna, wherein the shield trace encompasses a first region in which the first electrode overlaps the antenna and is absent from a second region different than the first region, in which the second electrode overlaps the antenna.
14. The electronic system of claim 13 , wherein the shield trace encompasses the first electrode.
15. The electronic system of claim 13 , wherein the first electrode is a receiver sensor electrode and the second electrode is a transmitter sensor electrode.
16. The electronic system of claim 13 , wherein the shield trace is wider than the first electrode.
17. The electronic system of claim 13 , wherein the plurality of sensor electrodes is configured to detect the input object based on a capacitive coupling between the first electrode and the second electrode.
18. The electronic system of claim 13 , wherein the second electrode has a wider trace width than the first electrode.
19. The electronic system of claim 13 , wherein the shield trace is coupled to a low impedance reference voltage.
20. The electronic system of claim 13 , wherein the antenna is configured to transmit and receive near field communication (NFC) signals.