Detecting applied forces on a display
AssigneeSynaptics Incorporated
InventorsPetr SHEPELEV, Byunghwee PARK
Life of this patent
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Abstract
The input devices described herein include force sensor electrodes that use capacitive sensing to measure the force with which an input object (e.g., a finger or stylus) presses down on the input device. To measure this force, the input device includes a compressible layer disposed between a backlight of a display in the input device and a cover window of the display. In one embodiment, the compressible layer is disposed between the backlight and a transparent thin-film transistor (TFT) layer in the display. In one embodiment, the compressible layer includes an air gap which has a thickness defined by adhesive material disposed on at least two edges of the display.
Claims20
An input device, comprising:
- a transparent thin-film transistor (TFT) layer;
- a backlight;
- a first compressible layer disposed between the TFT layer and the backlight;
- a plurality of force sensor electrodes disposed on a first side of the first compressible layer, wherein the plurality of force sensor electrodes is disposed between the first compressible layer and a cover window;
- a conductive grounding layer disposed on a second side of the first compressible layer opposite the first side;
- and
- a processing system configured to:
- acquire a plurality of capacitive measurements using the plurality of force sensor electrodes when the grounding layer is electrically grounded, wherein the plurality of capacitive measurements is affected by compression of the first compressible layer by an input object pressing on the cover window;
- and
- determine at least one force measurement of the input object based on the plurality of capacitive measurements.
A method of operating an input device, the method comprising:
- acquiring, when grounding a conductive layer, a plurality of capacitive measurements using a plurality of force sensor electrodes of the input device, wherein the plurality of capacitive measurements is affected by compression of a first compressible layer in the input device when an input object presses on a cover window, wherein the first compressible layer is disposed between a transparent thin-film transistor (TFT) layer and a backlight in the input device, wherein the plurality of force sensor electrodes is disposed between the first compressible layer and the cover window, and wherein the plurality of force sensor electrodes is disposed on a first side of the first compressible layer and the conductive layer is disposed on a second side of the first compressible layer opposite the first side;
- and
- determining force measurements corresponding to the input object based on the plurality of capacitive measurements.
A display comprising:
- a liquid crystal material layer;
- a first layer comprising a plurality of force sensor electrodes;
- and
- a transparent thin-film transistor (TFT) layer, wherein the first layer is disposed between the liquid crystal material layer and the TFT layer;
- a backlight;
- a compressible layer disposed between the TFT layer and the backlight, wherein the plurality of force sensor electrodes is disposed on a first side of the compressible layer, and wherein the plurality of force sensor electrodes is disposed between the compressible layer and a cover window;
- and
- a conductive grounding layer disposed on a second side of the compressible layer opposite the first side,
- wherein the plurality of force sensor electrodes is configured to generate capacitive signals affected by compression of the compressible layer in response to force applied by an input object on the cover window while the conductive grounding layer is electrically grounded.
Dependencies are inferred from the claim text.