Abstract: Described are methods and devices including a touch sensor layer configured to receive touch input and a force sensor layer stacked with the touch sensor layer, the force sensor layer includes an array of force sensors configured to receive force input. The force sensor array includes individual force sensors. Specific sensors of the disclosed force sensor array are associated with specific locations of the touch screen to add information that can be used to decipher which key is actually being pressed and may avoid falsing. Both a touch signal and a force signal are utilized to determine the validity of a user touch input. In one embodiment each force sensor may operate independently of the others. Particular embodiments are described that utilize a coarse grid to determine valid touch inputs and that make a determination of a centroid location based on a plurality of force sensors to determine valid touch inputs.

Abstract: A stylus (100) is configured for actively interacting with a touch-sensitive interface (201) by injecting or sinking charge in response to a touch-detection signal emitted from the touch-sensitive interface (201). One stylus (100) includes a stylus body (104) and a compound tip (105) extending axially from the stylus body (104). The compound tip (105) can include a center electrode (101) that is configured to detect electric field variations from the touch-sensitive interface (201) and a shroud electrode (102) that is concentrically disposed about the center electrode (101). An active circuit (103) coupled between the center electrode (101) and the shroud electrode (102) is configured to apply a gain to the detected electric field variations and to change a potential of the shroud electrode (102) synchronously with the electric field variations detected by the center electrode (101).

Abstract: A stylus (100) is configured for actively interacting with a touch-sensitive interface (201) by injecting or sinking charge in response to a touch-detection signal emitted from the touch-sensitive interface (201). One stylus (100) includes a stylus body (104) and a compound tip (105) extending axially from the stylus body (104). The compound tip (105) can include a center electrode (101) that is configured to detect electric field variations from the touch-sensitive interface (201) and a shroud electrode (102) that is concentrically disposed about the center electrode (101). An active circuit (103) coupled between the center electrode (101) and the shroud electrode (102) is configured to apply a gain to the detected electric field variations and to change a potential of the shroud electrode (102) synchronously with the electric field variations detected by the center electrode (101).

Abstract: A capacitive force sensor (100) includes a substrate (101) having at least one electrode pair (102,103) defining a capacitance disposed thereon. The substrate (101) is fixed relative to a first plate (106). A drive circuit (104) is configured to apply a voltage relative to a circuit ground (105) to the electrode pair (102,103). The first plate (106) is separated from a second plate (107) that is coupled to circuit ground (105) by a compliance member (108,109). The compliance member (108,109) is configured to oppose a compression force (110) while allowing the first plate (106) to physically move relative to the second plate (107). A capacitive detection circuit (111) is then configured to detect a change the capacitance when the compliance member (108,109) is compressed. The compression force (110) is then determined from the change in capacitance and the spring constant of the compliance member (108,109).

Abstract: Described are methods and devices including a touch sensor layer configured to receive touch input and a force sensor layer stacked with the touch sensor layer, the force sensor layer includes an array of force sensors configured to receive force input. The force sensor array includes individual force sensors. Specific sensors of the disclosed force sensor array are associated with specific locations of the touch screen to add information that can be used to decipher which key is actually being pressed and may avoid falsing. Both a touch signal and a force signal are utilized to determine the validity of a user touch input. In one embodiment each force sensor may operate independently of the others.

Abstract: A capacitive force sensor (100) includes a substrate (101) having at least one electrode pair (102,103) defining a capacitance disposed thereon. The substrate (101) is fixed relative to a first plate (106). A drive circuit (104) is configured to apply a voltage relative to a circuit ground (105) to the electrode pair (102,103). The first plate (106) is separated from a second plate (107) that is coupled to circuit ground (105) by a compliance member (108,109). The compliance member (108,109) is configured to oppose a compression force (110) while allowing the first plate (106) to physically move relative to the second plate (107). A capacitive detection circuit (111) is then configured to detect a change the capacitance when the compliance member (108,109) is compressed. The compression force (110) is then determined from the change in capacitance and the spring constant of the compliance member (108,109).