Display devices and methods for detecting user-intended touch input

• US 9,292,119 B2
• Filed: 08/01/2014
• Issued: 03/22/2016
• Est. Priority Date: 05/21/2012
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Miller, Duane S., Noble, Robert T.
• Primary Examiner(s): Okebato, Sahlu
• Application Number:
  US14/449,256
• Publication Number:
  US 20140340346A1
• Time in Patent Office: 599 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/0421 by interrupting or reflecting a light beam, e.g. optical touch-screen

Abstract

Display devices and methods for detecting user-intended touch input are provided. An example display device includes a touch-sensitive display. Further, the display device includes an impact sensor attached to the touch-sensitive display and configured to generate a signal representative of an impact of the touch-sensitive display. The display device also includes a computing device configured to receive the signal. The computing device is also configured to detect a peak of the signal. Further, the computing device is configured to determine whether a rising edge of a magnitude of the peak detected signal meet predetermined criteria. The computing device is also configured to indicate detection of user-intended touch in response to determining that the predetermined criteria are met.

Claims

1. A display device comprising:

a touch-sensitive display;

an impact sensor attached to the touch-sensitive display and configured to generate a signal representative of impacts to the touch-sensitive display; and

a computing unit configured to;

receive the signal;

determine whether a predetermined fraction of the signal is greater than a low-pass filter output of the signal; and

indicate detection of user-intended touch in response to determining that the predetermined fraction of the signal is greater than a low-pass filter output of the signal,

wherein the computing unit is configured to detect a peak value of the signal, and

wherein the computing unit comprises;

a voltage divider configured to receive the peak detected signal and generate a first output that is a fraction of the peak detected signal;

a low pass filter configured to receive the peak detected signal and to apply low-pass filtering to the peak detected signal to generate a second output; and

a comparator configured to receive the first and second outputs as inputs and to generate a trigger pulse in response to the first output being greater than the second output to indicate detection of user-intended touch.

2. The display device of claim 1, wherein the impact sensor is a piezoelectric sensor.

3. The display device of claim 1, wherein the impact sensor is in vibrational communication with the touch-sensitive display.

4. The display device of claim 1, wherein the computing unit comprises a peak detector configured to filter background noise in the signal.

5. The display device of claim 1, wherein the predetermined fraction is defined by a voltage divider that is configured to receive the signal as input and to output the predetermined fraction of the signal.

6. The display device of claim 1, wherein the low pass filter has a time constant between about 1 and 100 milliseconds.

7. The display device of claim 1, wherein the voltage divider is configured to selectively adjust a magnitude of the first output to adjust a detection threshold level of detection of the user-intended touch.

8. The display device of claim 7, wherein the voltage divider is configured to receive user input for adjusting the detection threshold level.

9. The display device of claim 1, further comprising an amplifier configured to receive and amplify the signal from the impact sensor.

10. The display device of claim 1, further comprising a touch controller configured to:

determine a touch event associated with the touch-sensitive display;

determine a coordinate associated with the touch event;

determine whether the touch event occurs when the predetermined criteria is met;

in response to determining that the touch event occurs when the predetermined criteria is met, communicate the coordinate to a user interface manager.

11. The display device of claim 1, wherein the computing unit is configured to indicate that user-intended touch is not detected in response to determining that the predetermined fraction of the signal is not greater than the low-pass filter output of the signal.

12. A method comprising:

generating a signal representative of an impact to a touch-sensitive display;

determining whether a predetermined fraction of the signal is greater than a low-pass filter output of the signal;

in response to determining that the predetermined fraction of the signal is greater than a low-pass filter output of the signal, indicating detection of user-intended touch;

using a voltage divider to receive a peak detected signal and to generate a first output that is a fraction of the peak detected signal;

using a low pass filter to receive the peak detected signal and to apply low-pass filtering to the peak detected signal to generate a second output; and

generating an indication in response to the first output being greater than the second output to indicate detection of user-intended touch.

13. The method of claim 12, wherein generating the signal comprises using an impact sensor attached to the touch-sensitive display to generate the signal.

14. The method of claim 13, wherein the impact sensor is in vibrational communication with the touch-sensitive display.

15. The method of claim 12, further comprising filtering background noise in the signal.

16. The method of claim 15, wherein filtering background noise comprises using a peak detector with a recovery time constant between about 0.1 and 10 seconds.

17. The method of claim 12, wherein the low pass filter has a time constant between about 1 and 100 milliseconds.

18. The method of claim 12, further comprising selectively adjusting the voltage divider to adjust a magnitude of the first output to adjust a detection threshold level of detection of the user-intended touch.

19. The method of claim 12, receiving user input for adjusting the detection threshold level.

20. The method of claim 12, further comprising:

receiving the signal from an impact sensor attached to the touch-sensitive display; and

amplifying the signal from the impact sensor.

21. The method of claim 12, further comprising:

determining a touch event associated with the touch-sensitive display;

determining a coordinate associated with the touch event;

determining whether the touch event occurs when the predetermined criteria is met;

in response to determining that the touch event occurs when the predetermined criteria is met, communicating the coordinate to a user interface manager.

22. The method of claim 12, further comprising indicating that user-intended touch is not detected in response to determining that the predetermined fraction of the signal is not greater than the low-pass filter output of the signal.