Modulated back plate for capacitive sensing
AssigneeSynaptics Incorporated
InventorJeffrey A. SMALL
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Abstract
Embodiments described herein include an input device comprising a display device having an integrated capacitive sensing device, a processing system, and a method for detecting presence of an input object. In each of these embodiments, a modulation source provides modulation signals between a back plate and a system ground of the input device. Other embodiments include a display device having a capacitive sensing device, a processing system and a method for detecting presence of an input object using a capacitive sensing device, wherein the capacitive sensing device includes a matrix of discrete sensor electrodes.
Claims21
An input device comprising a display device having an integrated capacitive sensing device, the input device comprising;
- a system ground;
- a conductive back plate configured to be coupled to an input object;
- a plurality of sensor electrodes;
- and
- a processing system coupled to the conductive back plate and the plurality of sensor electrodes, the processing system configured to:
- drive modulation signals onto the conductive back plate;
- and
- receive resulting signals with at least one of the plurality of sensor electrodes, the resulting signals comprising effects corresponding to the modulation signals;
- wherein the modulation signals cause the conductive back plate and the input object to be modulated with respect to system ground.
A method for capacitive sensing, the method comprising:
- driving modulation signals onto a conductive back plate that is proximate to a display device having an integrated capacitive sensing device;
- and
- receiving resulting signals from at least one of a plurality of sensor electrodes that are included in the display device having the integrated capacitive sensing device, the resulting signals comprising effects corresponding to the modulation signals;
- wherein the modulation signals cause the conductive back plate and an input object proximate to the at least one sensor electrode to be modulated with respect to system ground.
A processing system for an input device, the processing system comprising:
- a modulation source configured to drive modulation signals onto a conductive back plate that is proximate to a display device having an integrated capacitive sensing device;
- and
- a sensor module having sensing circuitry configured to receive resulting signals from at least one of a plurality of sensor electrodes that are included in the display device having the integrated capacitive sensing device, the resulting signals comprising effects corresponding to the modulation signals;
- wherein the modulation signals cause the conductive back plate and an input object proximate to the at least one sensor electrode to be modulated with respect to system ground.
Dependencies are inferred from the claim text.