Electromagnetic 3D stylus

摘要

A stylus system and method for determining the three-dimensional position and orientation of a stylus operating within a volume located above a surface of a display device is described. In some embodiments, the stylus system includes a stylus and a display device. The stylus senses one or more magnetic fields generated from a set of transmitting coils associated with the display device and transmits sensing information over an RF channel to a receiver in the display device. The display device determines the three-dimensional position of the stylus by applying a cell-based position reconstruction technique that compares the received sensing information with predetermined magnetic field values associated with one or more predetermined regions located above the surface of the display device. The cell-based position reconstruction technique accommodates magnetic field distortions due to the presence of conductive elements within or near the display device.

主权项

1. A method for determining a position of a stylus, comprising:
generating one or more drive signals, each of the one or more drive signals is associated with a particular transmission coil of one or more transmission coils, the one or more transmission coils are associated with a display device; generating one or more magnetic fields, each of the one or more magnetic fields is associated with a particular drive signal of the one or more drive signals; sensing one or more voltages, each of the one or more voltages is associated with a particular receiving coil of one or more receiving coils, the one or more voltages are generated by the one or more magnetic fields, the one or more receiving coils are associated with the stylus; transmitting sensing information based on the one or more voltages from the stylus to the display device, the sensing information includes a set of field numbers that represent the sensed magnetic field strength from each of the one or more transmission coils to each of the one or more receiving coils; and determining the position of the stylus within one or more predetermined regions located above a surface of the display device, the determining the position of the stylus includes determining a first region of the one or more predetermined regions based on the received sensing information, the first region is associated with one or more polynomials describing magnetic fields associated with each of the one or more transmission coils, the determining the position of the stylus includes determining one or more neighboring regions adjacent to the first region, the determining the position of the stylus includes determining an interpolated position of the stylus based on magnetic field strength data associated with the one or more neighboring regions and the first region.