Touch interface with person recognition

Patent metadata

Field	Value
Publication number	US-9626058-B2
Application number	US-201514919061-A
Country	US
Kind code	B2
Filing date	Oct 21, 2015
Priority date	Jun 10, 2015
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

Identifying a tool touching a touchscreen device. A touch location of a tool on a touch-sensitive surface is received from a touchscreen controller. Based on the touch location, one of a plurality of electrodes disposed at locations across the touchscreen is selected and an electric circuit is enabled. The electric circuit includes a signal generator attached to the tool that transmits a modulated identification (ID) signal, a parasitic capacitance path between the signal generator and the selected electrode, a demodulator connected to the selected electrode that receives the ID signal, a resistive layer connected to the demodulator, covering the touch-sensitive surface, and a resistive path through the tool to the signal generator. The demodulator demodulates the modulated ID signal to recover a bit sequence. The tool is identified, based on the recovered bit sequence.

First claim

What is claimed is:

1. A method for identifying a tool touching a touchscreen device, the method comprising:
providing 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;

providing 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;

determining, by the touch detection circuitry, a touch location of a tool touching the touch-sensitive surface;
selecting, by the electrode selector switch, one of the plurality of electrodes nearest to the touch location, whereby a tool identification circuit is completed that includes:
the signal generator attached to the tool;
a resistive path through the tool coupling the signal generator to the resistive layer;
the demodulator coupled to the resistive layer;
the selected electrode;
the electrode selector switch coupled to selected electrode and the demodulator; and
a parasitic capacitance path coupling the signal generator to the selected electrode;

transmitting, by the signal generator, over the tool identification circuit, a modulated identification (ID) signal;
receiving, by the demodulator, over the tool identification circuit, the modulated ID signal;
demodulating, by the demodulator, the modulated ID signal to recover a bit sequence; and
identifying, by one or more processors, the tool, based on the recovered bit sequence.

2. A method in accordance with claim 1 , wherein selecting, by the electrode selector switch, one of the plurality of electrodes nearest to the touch location, whereby a tool identification circuit is completed, comprises:
selecting a first electrode nearest to the touch location;
in response to determining that the recovered bit sequence is not valid, selecting an electrode at an alternative location to include in completing the tool identification circuit.

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

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

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

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

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

9. A method 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

• G06K9/62

  Physics · mapped topic

• G06F2203/04104

  Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger · CPC title

• G06F2203/04106

  Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F3/014

  Hand-worn input/output arrangements, e.g. data gloves · CPC title