Touch interface with person recognition

Patent metadata

Field	Value
Publication number	US-2016364052-A1
Application number	US-201514735202-A
Country	US
Kind code	A1
Filing date	Jun 10, 2015
Priority date	Jun 10, 2015
Publication date	Dec 15, 2016
Grant date	—

Abstract

A system for identifying a tool touching a touchscreen device includes a touch-sensitive surface that generates a signal in response to a touch from a tool touching the surface; a touchscreen controller that receives the signal from the touch-sensitive surface and determines the location of the touch; logic to select, based on the touch location, one of a plurality of electrodes disposed across the touch-sensitive surface; logic to enable an electric circuit that includes a signal generator attached to the tool that transmits a modulated ID signal; a parasitic capacitance path between the signal generator and the electrode; a demodulator connected to the electrode that receives and demodulates the modulated ID signal to recover a bit sequence; a resistive layer, connected to the demodulator, covering the touch-sensitive surface; a resistive path through the tool to the resistive layer; and logic that identifies the tool, based on the recovered bit sequence.

First claim

1 . A system for identifying a tool touching a touchscreen device, the system comprising:
touch detection circuitry, including:
a touch-sensitive surface operated to generate a signal in response to a tool touching the surface; and
a touchscreen controller operated to receive the signal from the touch-sensitive surface and determine a location of the touch; and
tool identification circuitry, including:
a signal generator attached to the tool;
a resistive path through the tool that couples the signal generator to a resistive layer covering the touch-sensitive surface;
a demodulator coupled to the resistive layer;
a plurality of electrodes disposed at locations across the touch-sensitive surface;
an electrode selector switch coupled to the plurality of electrodes and the demodulator; and
a parasitic capacitance path that couples the signal generator to one or more of the plurality of electrodes;
wherein: the electrode selector switch is operated to select one of the plurality of electrodes that is nearest to the touch location determined by the touch detection circuitry, thereby completing a circuit that includes the signal generator, the resistive path through the tool, the resistive layer, the demodulator, the selected electrode, and the parasitic capacitance path; the signal generator is operated to transmit a modulated identification (ID) signal over the circuit: the demodulator is operated to receive the modulated ID signal over the circuit, and to demodulate the modulated ID signal and recover a bit sequence; and logic is operated to identify the tool, based on the recovered bit sequence.

2 . A system in accordance with claim 1 , wherein the selector switch is further operated to:
in response to determining that the recovered bit sequence is not valid, select an electrode at an alternative location to include in completing the electric circuit.

3 . A system in accordance with claim 1 , wherein the tool is a finger, the signal generator is included in a user-wearable device, and the resistive path includes skin of the finger.

4 . A system in accordance with claim 3 , wherein the user-wearable device is one of a ring or a bracelet.

5 . A system in accordance with claim 1 , wherein the electrode selector switch is a mux.

6 . A system in accordance with claim 1 , wherein the plurality of electrodes are disposed at locations across the touch-sensitive surface in parallel rows.

7 . A system in accordance with claim 1 , wherein the ID signal is modulated using frequency-shift keying.

8 . A system in accordance with claim 7 , wherein frequency-shift keying comprises binary frequency-shift keying.

9 . A system in accordance with claim 8 , wherein demodulating the modulated ID signal comprises using a Goertzel algorithm.

Assignees

• IBM

Inventors

• Castellani Marzia E
• Medina Ana Lucia
• Ragusa Roberto
• Rea Aniello Alessandro

Classifications

• G06F3/0486

  Drag-and-drop · CPC title

• G06K7/10396

  the interrogation device being wearable, e.g. as a glove, bracelet, or ring (wearable aerials in general H01Q1/27) · CPC title

• G06F3/0412 Primary

  Digitisers structurally integrated in a display · CPC title

• G06K9/00087

  Physics · mapped topic

• G06F3/0414

  using force sensing means to determine a position · CPC title