Force sensing using capacitive touch surfaces
First Claim
1. A touch-sensitive input device comprising:
- a glass-plus-sensor module including;
a cover glass including a top surface and a bottom surface; and
at least two electrodes attached to the bottom surface of the cover glass, the at least two electrodes having an associated self-capacitance;
an adhesive layer attached to the bottom surface of the cover glass, the adhesive layer having a thickness; and
a processor configured to calculate a force applied by a contact with the top surface of the cover glass based on a change in self-capacitance for each electrode and the thickness of the adhesive layer, the change in self-capacitance for each electrode being caused by the force applied by the contact bending the glass-plus-sensor module toward the adhesive layer.
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Accused Products
Abstract
In one general aspect, a method can include identifying contact with a surface of a touch-sensitive input device, identifying a location of the contact on the surface of the touch-sensitive input device, and calculating a change in a mutual capacitance between a first electrode and a second electrode included in a sensor module disposed below the surface of the touch-sensitive input device. The first electrode can be adjacent to the second electrode. The first electrode and the second electrode can be located approximate to the identified location of the contact on the surface of the touch-sensitive input device. The method can include estimating a contact-coupled capacitance based on the calculated change in a mutual capacitance between the first electrode and the second electrode, and calculating a force applied to the surface of the touch-sensitive input device at the identified location.
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Citations
18 Claims
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1. A touch-sensitive input device comprising:
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a glass-plus-sensor module including; a cover glass including a top surface and a bottom surface; and at least two electrodes attached to the bottom surface of the cover glass, the at least two electrodes having an associated self-capacitance; an adhesive layer attached to the bottom surface of the cover glass, the adhesive layer having a thickness; and a processor configured to calculate a force applied by a contact with the top surface of the cover glass based on a change in self-capacitance for each electrode and the thickness of the adhesive layer, the change in self-capacitance for each electrode being caused by the force applied by the contact bending the glass-plus-sensor module toward the adhesive layer. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A computing device comprising:
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at least one controller; and a touch-sensitive input device configured to facilitate interaction by a user with a graphical user interface (GUI), the touch-sensitive input device comprising; a glass-plus-sensor module including; a cover glass including a top surface and a bottom surface; and at least two electrodes attached to the bottom surface of the cover glass, the at least two electrodes having an associated self-capacitance; a display device having a top surface and a bottom surface, the computing device being configured to render the GUI on the display device; an optically clear adhesive (OCA) layer attaching the bottom surface of the cover glass to the top surface of the display device, the OCA layer having a thickness; and a ground plane attached to the bottom surface of the display device, wherein the at least one controller and the touch-sensitive input device are collectively configured to; detect contact of a conductive element with the top surface of the cover glass; and based on the detected contact, determine, for each of the at least two electrodes, a self-capacitance associated with the electrode; and calculate a force applied by the contact of the conductive element with the top surface of the cover glass based on the determined self-capacitance associated with each of the at least two electrodes, the thickness of the OCA layer, and proportionality of the self-capacitance to the thickness of the OCA layer, the change in self-capacitance for each electrode being caused by the force applied by the contact of the conductive element bending the glass-plus-sensor module toward the OCA layer. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A touch-sensitive input device comprising:
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a glass-plus-sensor module including; a cover glass including a top surface and a bottom surface; and at least three electrodes attached to the bottom surface of the cover glass, each of the at least three electrodes having an associated self-capacitance; a display device, the glass-plus-sensor module bending towards the display device at a point of contact of a conductive element with the top surface of the cover glass, the bending changing, for each of the at least three electrodes, the self-capacitance associated with each of the at least three electrodes, and a calculation of a force applied by the contact of the conductive element with the top surface of the cover glass being based on the change in self-capacitance for each of the at least three electrodes, and an optically clear adhesive (OCA) layer attaching the bottom surface of the cover glass to the top surface of the display device, the OCA layer having a thickness, wherein the calculation of the force applied by the contact of the conductive element with the top surface of the cover glass is further based on the thickness of the OCA layer. - View Dependent Claims (15, 16, 17, 18)
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Specification