FAST MULTI-TOUCH SENSOR

• US 20170262135A1
• Filed: 05/26/2017
• Published: 09/14/2017
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Tactual Labs Co.
• Original Assignee: Tactual Labs Co.
• Inventors: Wigdor, Daniel
• Granted Patent: US 10,444,915 B2
• Time in Patent Office: Days
• CPC Class Codes: G06F 2203/0382 Plural input, i.e. interface arrangements in which a plurality of input device of the same type are in communication with a PC
• CPC Class Codes: G06F 2203/04104 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 Class Codes: G06F 2203/04109 FTIR in optical digitiser, i.e. touch detection by frustrating the total internal reflection within an optical waveguide due to changes of optical properties or deformation at the touch location
• CPC Class Codes: G06F 3/03542 Light pens for emitting or receiving light
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

A low-latency touch sensor is disclosed for use in connection with a touch surface having first and second conductors sensitive to changes in coupling therebetween as a result of touch (and/or near-touch). A signal generator generates unique orthogonal signals, a transmitter transmits the orthogonal signals on each of the first conductors. Receivers connected to the second conductors receive signals during a measurement period. The signals measured during the measurement period are processed to determine, for each measurement period, and for each of the second conductors, a signal strength corresponding to each of the unique orthogonal signals. The signal strengths can be used as a basis to determine touch events.

Claims

1. A low-latency touch sensor for use in connection with a touch surface having a first and second plurality of conductors being arranged such that each of the paths of the conductors of the first plurality of conductors cross each of the paths of the conductors of the second plurality of conductors, and wherein when the touch surface is not being touched a first amount of signal is coupled between them, and when the touch surface is being touched a different amount of signal is coupled between them, the low-latency touch sensor comprising:

signal generator adapted to generate a plurality of unique frequency orthogonal signals, each unique frequency orthogonal signal being orthogonal to each of the other unique frequency orthogonal signals;

transmitter operatively connected to each of the first and second plurality of conductors, the transmitter adapted to;

transmit each of a first set of signals from the plurality of unique frequency orthogonal signals on each of the first plurality of conductors simultaneously; and

transmit each of a second set of signals from the plurality of unique frequency orthogonal signals on each of the second plurality of conductors simultaneously;

receiver operatively connected to each of the first and second plurality of conductors the receiver adapted to receive signals from each of the first and second plurality of conductors; and

signal processor adapted to determine a strength for each of the unique frequency orthogonal signals in the signals received by the receiver.

2. The device claimed in claim 1, wherein

the transmitter is adapted to simultaneously transmit on the first plurality of conductors and transmit on the second plurality of conductors, and wherein

the first set of signals and the second set of signals contain no common signals.

3. A low-latency touch sensor for use in connection with a touch surface having a first and second plurality of conductors being arranged such that each of the paths of the conductors of the first plurality of conductors cross each of the paths of the conductors of the second plurality of conductors, and wherein when the touch surface is not being touched a first amount of signal is coupled between them, and when the touch surface is being touched a different amount of signal is coupled between them, the low-latency touch sensor comprising:

signal generator adapted to generate a plurality of unique orthogonal signals, each unique orthogonal signal being orthogonal to each of the other unique orthogonal signals and each unique orthogonal signal being pre-selected so as to have no simple harmonic relationship with the other unique orthogonal signals, the plurality of unique orthogonal signals having a lowest frequency and a highest frequency, the highest frequency being less than twice the lowest frequency;

transmitter operatively connected to the first plurality of conductors, the transmitter adapted to simultaneously transmit each of the plurality of unique orthogonal signals on each of the first plurality of conductors, respectively;

receiver operatively connected to the second plurality of conductors, the receiver adapted to receive signals during a measurement period τ

from each of the second plurality of conductors; and

signal processor adapted to determine a strength for each of the unique orthogonal signals in the signals received by the receiver during the measurement period, such that for each measurement period one signal strength is determined for each of the plurality of unique orthogonal signals for each of the second plurality of conductors.

4. The device claimed in claim 3, wherein changes in signal coupling between crossing conductors is a result of touch in proximity to the cross.

5. The device claimed in claim 3, wherein the plurality of unique orthogonal signals are spaced from one-another by a spacing Δ

f that is at least the reciprocal of the measurement period τ

.

6. The device claimed in claim 3, wherein the plurality of unique orthogonal signals are spaced from one-another by a spacing Δ

f that is the reciprocal of the measurement period τ

.

7. The device claimed in claim 3, further comprising:

modulator for modulating the plurality of unique orthogonal signals prior to transmission;

demodulator for demodulating the plurality of unique orthogonal signals prior to decoding;

wherein modulation and demodulation of the plurality of unique orthogonal signals are opposite functions; and

wherein the transmitter transmits and the receiver receives the modulated unique orthogonal signals.

8. The device claimed in claim 3, wherein the signal processor performs a Fourier transform in connection with the decoding of signals.

9. The device claimed in claim 3, wherein the signal processor utilizes a filter bank in connection with the decoding of signals.

10. The device claimed in claim 3, further comprising a heterodyne for reducing the frequency of the signals from each of the second plurality of conductors prior to being decoded by the signal processor.

11. The device claimed in claim 3, wherein the first and second plurality of conductors each comprises a thin irregular web of conductive material.

12. The device claimed in claim 4, further comprising:

interpolator for determining the location of touch from information including the determined strength of each of the unique orthogonal signals.

13. The device claimed in claim 4, further comprising touch event identifier adapted to analyze the determined strengths, and determine touch based thereon.

14. The device claimed in claim 4, further comprising touch event identifier adapted to analyze the determined strengths over a plurality of measurement periods and identify touch events based thereon.

15. A low-latency touch sensor for use in connection with a touch surface having a first and second plurality of conductors being arranged such that each of the paths of the conductors of the first plurality of conductors cross each of the paths of the conductors of the second plurality of conductors, and wherein when the touch surface is not being touched a first amount of signal is coupled between them, and when the touch surface is being touched a different amount of signal is coupled between them, the low-latency touch sensor comprising:

signal generator adapted to generate a plurality of unique orthogonal signals, each unique orthogonal signal being orthogonal to each of the other unique orthogonal signals and each unique orthogonal signal being spaced apart from one-another by a spacing and being pre-selected so as to have no simple harmonic relationship with the other unique orthogonal signals;

transmitter operatively connected to the first plurality of conductors, the transmitter adapted to simultaneously transmit each of the plurality of unique orthogonal signals on each of the first plurality of conductors, respectively;

receiver operatively connected to the second plurality of conductors, the receiver adapted to receive signals during a measurement period from each of the second plurality of conductors; and

signal processor adapted to determine a strength for each of the plurality of unique orthogonal signals in the signals received by the receiver during the measurement period, such that for each measurement period one signal strength is determined for each of the plurality of unique orthogonal signals for each of the second plurality of conductors.

16. The device claimed in claim 15, wherein the spacing is at least the reciprocal of the measurement period.

17. The device claimed in claim 15, wherein the spacing is the reciprocal of the measurement period.

18. The device claimed in claim 15, further comprising:

interpolator for determining the location of touch from information including the determined strength of each of the unique orthogonal signals.

19. The device claimed in claim 15, wherein changes in signal coupling between crossing conductors is a result of touch in proximity to the cross, the device further comprising touch event identifier adapted to analyze the determined strengths, and determine touch based thereon.

20. The device claimed in claim 15, wherein changes in signal coupling between crossing conductors is a result of touch in proximity to the cross, the device further comprising touch event identifier adapted to analyze the determined strengths over a plurality of measurement periods and identify touch events based thereon.