Integrated in-plane switching

• US 9,348,475 B2
• Filed: 07/03/2014
• Issued: 05/24/2016
• Est. Priority Date: 06/13/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven P., Zhong, John Z.
• Primary Examiner(s): Patel, Kumar
• Assistant Examiner(s): WOO, KUO-KONG
• Application Number:
  US14/323,788
• Publication Number:
  US 20140320454A1
• Time in Patent Office: 691 Days
• Field of Search: 345/173, 345/179
• US Class Current: 1/1
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• 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 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

This relates to adding multi-touch functionality to a display without the need of a separate multi-touch panel or layer overlaying the display. Instead, embodiments of the invention can advantageously utilize existing display circuitry to provide multi-touch functionality while adding relatively little circuitry that is specific to the multi-touch functionality. Thus, by sharing circuitry for the display and the multi-touch functionalities, embodiments of the invention can be implemented at a lower cost than the alternative of superimposing additional multi-touch related layers onto an existing display panel. Furthermore, since the display and multi-touch functionality can be implemented on the same circuit, they can be synchronized so that noise resulting from the display functionality does not detrimentally affect the multi-touch functionality and vice versa.

Claims

1. A touch enabled display device configured for operation in a display mode and a touch mode, the device comprising:

a touch stimulus region having at least one display pixel having a data line configured to transmit a display data signal in the display mode and a stimulation signal in the touch mode;

capacitive sensing circuitry configured for detecting changes in capacitance between the touch stimulus region and an adjacent charge sensor region of the touch enabled display device while the stimulation signal is being transmitted to the touch stimulus region during the touch mode; and

a switch configured to switch the data line between the display mode and the touch mode.

2. The touch enabled display device of claim 1, wherein the at least one display pixel comprises a plurality of display pixels, a portion of the plurality of display pixels sharing the same data line, and wherein

each display pixel of the plurality of display pixels has a data line configured to transmit a display data signal in the display mode and a stimulation signal in the touch mode;

and

at least for each display pixel in the portion of the first plurality of display pixels, the touch enabled display device includes a switch configured to switch the data line between the display mode and the touch mode.

3. The touch enabled display device of claim 1, wherein the at least one display pixel comprises a plurality of display pixels and the touch enabled display device further comprising a plurality of counter data lines coupled to the first plurality of display pixels during the touch mode.

4. The touch enabled display device of claim 3, wherein each display pixel of the plurality of display pixels has a first electrode and a second electrode, the first electrode coupled to the corresponding data line and the second electrode coupled to one of the plurality of counter data lines during the touch mode.

5. The touch enabled display device of claim 4, wherein the stimulation signal is coupled to the counter data lines during the touch mode.

6. The touch enabled display device of claim 1, further comprising a first counter data line coupled to the at least one display pixel during the touch mode.

7. The touch enabled display device of claim 6, wherein the at least one display pixel is a touch stimulus pixel having -a first electrode and a second electrode, the first electrode coupled to the data line and the second electrode coupled to the first counter data line.

8. The touch enabled display device of claim 7, further comprising at least one charge sensor pixel disposed in the charge sensor region and wherein the at least one charge sensor pixel has a data line configured to transmit another display data signal in the display mode and is coupled to the capacitive sensing circuitry in the touch mode.

9. The touch enabled display device of claim 8, further comprising a second counter data line and wherein the second counter data line is coupled to the charge sensor pixel during the touch mode.

10. The touch enabled display device of claim 9, wherein charge sensor pixel has a first and second electrode, the first electrode coupled the data line of the charge sensor pixel and the second electrode coupled to the second counter data line during the touch mode.

11. The touch enabled display device of claim 10, wherein the first electrode of the touch stimulus pixel is coupled to the data line of the touch stimulus pixel and the second electrode is coupled to the second counter data line.

12. The touch enabled display device of claim 1, wherein the at least one display pixel comprises a touch stimulus pixel and the device further comprising at least one charge sensor pixel and wherein the at least one charge sensor pixel has a data line configured to transmit another display data signal in the display mode and is coupled to the capacitive sensing circuitry in the touch mode.

13. A display device configured for operation in a display mode and a touch mode, the device comprising:

at least one touch stimulus pixel having a data line configured to transmit a display data signal in the display mode and a stimulation signal in the touch mode. the stimulus signal being distinct from the display data signal;

at least one charge sensor pixel, distinct from and adjacent to the at least one touch stimulus pixel, the charge sensor pixel having a data line configured to transmit another display data signal in the display mode and being coupled to capacitance sensing circuitry in the touch mode;

the capacitance sensing, circuitry configured to detect changes in mutual capacitance between the at least one touch stimulus pixel, while receiving the stimulation signal, and the at least one charge sensor pixel; and

a switch configured to switch the data line between the display mode and the touch mode.

14. The display device of claim 13, wherein the touch stimulus pixel has first electrode and a second electrode, the first electrode coupled to the data line of the touch stimulus pixel and the second electrode coupled to a first counter data line, the first counter data line coupled to transmit the stimulation signal in the touch mode.

15. The display device of claim 14, wherein the charge sensor pixel has first electrode and a second electrode, the first electrode coupled to the data line of the charge sensor pixel and the second electrode coupled to a second counter data line, the second counter data line coupled to the capacitance sensing circuitry in the touch mode.

16. The display device of claim 13, wherein the charge sensor pixel has first electrode and a second electrode, the first electrode coupled to the data line of the charge sensor pixel and the second electrode coupled to a counter data line, the counter data line coupled to the capacitance sensing circuitry in the touch mode.

17. The display device of claim 13, wherein the touch stimulus pixel has first electrode and a second electrode, the first electrode coupled to the data line of the touch stimulus pixel and the second electrode coupled to a first counter data line, the first counter data line coupled to transmit another stimulation signal in the touch mode.

18. The display device of claim 17, wherein the charge sensor pixel has first electrode and a second electrode, the first electrode coupled to the data line of the charge sensor pixel and the second electrode coupled to a second counter data line, the second counter data line coupled to the capacitance sensing circuitry in the touch mode.

19. The display device of claim 13, further comprising:

at least one guard pixel placed between the at least one touch stimulus pixel and the at least one charge sensor pixel, the at least one guard pixel having a data line configured to transmit yet another display data signal in the display mode and being coupled to a predefined voltage during the touch mode.

20. The display device of claim 19, wherein the predefined voltage is a ground voltage.

21. A display device configured for operation in a display mode and a touch mode, the device comprising:

a plurality of touch stimulus pixels having data lines configured to transmit first display data signals in the display mode and stimulation signals in the touch mode;

a plurality of charge sensor pixels having data lines configured to transmit display second data signals in the display mode and being coupled to capacitance sensing circuitry in the touch mode;

the capacitance sensing circuitry configured to detect changes in mutual capacitance between the at least one touch stimulus pixel, while receiving the stimulation signal, and the at least one charge sensor pixel; and

a switch configured to switch the data line between the display mode and the touch mode.

22. The display device of claim 21, wherein the plurality of touch stimulus pixels are disposed in a two dimensional array and the plurality of charge sensor pixels are disposed in a two dimension array adjacent the plurality of touch stimulus pixels.

23. The display device of claim 22, further comprising a plurality of guard pixels, the plurality of guard pixels disposed in a two dimensional array and positioned between the plurality of touch stimulus pixels and the plurality of charge sensor pixels.

24. A display and touch sensing method using a display having at least one touch stimulus pixel and at least one charge sensor pixel, the method comprising:

transmitting a first display data signal on a data line of the at least one touch stimulus pixel in a display mode;

transmitting a first stimulation signal on the data line of the at least one touch stimulus pixel in a touch mode;

transmitting a second display data signal on a data line of the at least one charge sensor pixel in the display mode;

detecting changes in capacitance between the at least one charge sensor pixel and the at least one touch stimulus pixel while the first stimulation signal is being transmitted to the at least one touch stimulus pixel during the touch mode; and

switching the data lines of the at least one touch stimulus pixel and the at least one charge sensor pixel between the display mode and the touch mode.

25. The method of claim 24, wherein the touch stimulus pixel has a first and second electrode and the method further comprises:

coupling the first electrode to the data line of the touch stimulus pixel in the display mode;

coupling the second electrode to a first counter data line; and

coupling the first counter data line to the stimulation signal in the touch mode.

26. The method of claim 24, wherein the charge sensor pixel has a first and second electrode and the method further comprises:

coupling the first electrode to the data line of the charge sensor pixel in the display mode;

coupling the second electrode to a second counter data line; and

coupling the second counter data line to the capacitance measuring circuitry in the touch mode.