Patent ID: 8284029

Claim:
An identification system, for identifying a position of a radio frequency (RF) device on a display, the RF device generating a response signal upon receiving an RF signal, the identification system comprising: a plurality of antenna units disposed on a same side of a plane, each antenna unit having a corresponding identifying area; a switching unit, coupled to the antenna units; an RF module, coupled to the switching unit, for generating the RF signal; a microcontroller, coupled to the switching unit and the RF module, for controlling the switching unit to select, as a selected antenna unit, at least one antenna unit among the plurality of antenna units to transmit the RF signal generated by the RF module, and for determining whether the RF device is positioned in an identifying area corresponding to the selected antenna unit according to whether the selected antenna unit receives the response signal; and a display disposed parallel to the plane, wherein the identification system is configured such that the RF device can be placed on the display, wherein images displayed on the display are responsive to the RF device, wherein each of the antenna units comprises a plurality of concentric ring antennas of different sizes having a same center, and the microcontroller estimates a distance between the RF device and the center according to a smallest ring antenna in the antenna unit having received the response signal, and wherein when it is determined that the RF device is not in a central area of the selected antenna unit, the microcontroller controls the display to display the central area of the selected antenna unit to instruct a user to relocate the RF device to the central area.