Active stylus for use with touch-sensitive interfaces and corresponding method

摘要

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).

主权项

1. A stylus configured for actively interacting with a touch-sensitive interface, the stylus comprising:
a stylus body; and a compound tip extending axially from the stylus body, the compound tip comprising:
a center electrode configured to detect electric field variations;a shroud electrode electrically and mechanically isolated from and disposed concentrically around the center electrode;a suppression shroud, disposed between the center electrode and the shroud electrode, electrically isolated from each of the center electrode and the shroud electrode, wherein the suppression shroud is electrically coupled to a common node of the stylus; andan active circuit coupled between the center electrode and the shroud electrode and configured to apply a gain to the electric field variations and to change a potential of the shroud electrode with the electric field variations.