TOUCH SENSITIVE DISPLAYS

• US 20150130750A1
• Filed: 05/30/2013
• Published: 05/14/2015
• Est. Priority Date: 05/31/2012
• Status: Active Grant

• Current Assignee: Zytronic Displays Limited (Zytronic Plc)
• Original Assignee: Zytronic Displays Limited (Zytronic Plc)
• Inventors: Morrison, Andrew
• Granted Patent: US 10,078,402 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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

Disclosed are a touch sensitive display and a method of operation thereof. The display comprises a sensor having an input put array of electrodes and, capacitively coupled thereto, an output array of electrodes and a controller operable to perform a scan operation at every intersection point of said input array. The scan operation comprises measuring a touch value for an intersection point; determining a proportional difference between said touch value and a base touch value for said intersection point as a proportion of said base touch value, wherein said base touch value is indicative of there being no touch event on the sensor; and comparing the proportional difference to a predetermined proportional touch threshold so as to determine whether there is a touch event at that point.

Claims

1. A touch sensitive display comprising a sensor having an input array of electrodes and, capacitively coupled thereto, an output array of electrodes;

wherein said touch sensitive display comprises a controller operable to perform a scan operation at every intersection point of said input array, said scan operation comprising;

measuring a touch value for an intersection point;

determining a proportional difference between said touch value and a base touch value for said intersection point as a proportion of said base touch value, wherein said base touch value is indicative of there being no touch event on the sensor; and

comparing said proportional difference to a predetermined proportional touch threshold so as to determine whether there is a touch event at that point.

2. The touch sensitive display as claimed in claim 1, wherein said controller is further operable to measure said base touch value for each intersection point.

3. The touch sensitive display as claimed in claim 1, wherein said proportional touch threshold is defined as the difference between a touch value and a base touch value, as a proportion of said base touch value, indicative of there being a touch event.

5. The touch sensitive display as claimed in claim 1, wherein said predetermined proportional touch threshold is between 10% and 30%.

6. The touch sensitive display as claimed in claim 1, wherein said sensor is operable such that a change in voltage applied to one of the electrodes of said input array results in a voltage pulse on the output array electrodes, the magnitude of which is indicative of a touch event.

7. The touch sensitive display as claimed in claim 1, wherein each of the electrodes of said input array of electrodes and of said output array of electrodes comprises a conducting wire individually insulated with an insulating coating.

8. The touch sensitive display as claimed in claim 7, wherein the conducting wire is of diameter 8 μ

m to 18 μ

m.

9. The touch sensitive display as claimed in claim 7, wherein the insulating coating comprises a polyurethane coating having a thickness of 1 μ

m to 2 μ

m.

10. The touch sensitive display as claimed in claim 1, wherein the electrodes of said input array of electrodes are arranged substantially orthogonal to the electrodes of said output array of electrodes, each intersection point being where an input electrode crosses an output electrode.

11. The touch sensitive display as claimed in claim 1, wherein said input array of electrodes and said output array of electrodes are laid over each other so as to form a single electrode array layer in the panel.

12. The touch sensitive display as claimed in claim 1, wherein said controller is further operable to detect a touch at an intersection point by transmitting a pulse on an input electrode and monitoring a corresponding pulse energy on one or more output electrodes, said corresponding pulse arising due to capacitive coupling between the input electrode and the one or more output electrodes.

4. (canceled)

13. A method of operating a touch sensitive display, said touch sensitive display comprising a sensor having an input array of electrodes and, capacitively coupled thereto, an output array of electrodes;

said method comprising performing a scan operation at every intersection point of said input array, said scan operation comprising;

measuring a touch value for an intersection point;

determining a proportional difference between said touch value and a base touch value for said intersection point as a proportion of said base touch value, wherein said base touch value is indicative of there being no touch event on the sensor; and

comparing said proportional difference to a predetermined proportional touch threshold so as to determine whether there is a touch event at that point.

14. The method as claimed in claim 13 further comprising the step of measuring said base touch value for each intersection point.

15. The method as claimed in claim 14, wherein said proportional touch threshold is defined as the difference between a touch value and a base touch value, as a proportion of said base touch value, indicative of there being a touch event.

17. The method as claimed in claim 13, wherein said predetermined proportional touch threshold is between 10% and 30%.

18. The method as claimed in claim 13, wherein a change in voltage applied to one of the electrodes of said input array results in a voltage pulse on the output array electrodes, the magnitude of which is indicative of a touch event.

19. The method as claimed in claim 13, wherein the electrodes of said input array of electrodes are arranged substantially orthogonal to the electrodes of said output array of electrodes, each intersection point being where an input electrode crosses an output electrode.

20. The method as claimed in claim 13, wherein said input array of electrodes and said output array of electrodes are laid over each other so as to form a single electrode array layer in the panel.

21. The method as claimed in claim 13, wherein said method further comprises detecting a touch at an intersection point by transmitting a pulse on an input electrode and monitoring a corresponding pulse energy on one or more output electrodes, said corresponding pulse arising due to capacitive coupling between the input electrode and the one or more output electrodes.

22. A program carrier comprising computer readable instructions which, when run on a suitable apparatus, cause the apparatus to perform the method of claim 13.

23. The method as claimed in claim 13, wherein said proportional touch threshold is defined as the difference between a touch value and a base touch value, as a proportion of said base touch value, indicative of there being a touch event.

16. (canceled)