Touch-display crosstalk

• US 9,335,870 B2
• Filed: 09/07/2010
• Issued: 05/10/2016
• Est. Priority Date: 06/07/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Yousefpor, Marduke, Hotelling, Steven Porter, White, Kevin J.
• Primary Examiner(s): Chang, Kent
• Assistant Examiner(s): Lu, William
• Application Number:
  US12/877,070
• Publication Number:
  US 20110298727A1
• Time in Patent Office: 2,072 Days
• Field of Search: 345204-215, 345690-699, 345/156, 345173-179
• US Class Current: 1/1
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details

Abstract

Clamping of a circuit element of a touch screen, such as a gate line of the display system of the touch screen, to a fixed voltage is provided. The circuit element can be clamped during a touch phase and unclamped during a display phase of the touch screen. A gate line system of a touch screen can include a first transistor with a source or drain connected to a first gate line, a second transistor with a source or drain connected to a second gate line, and a common conductive pathway connecting gates of the first and second transistors. A synchronization system can switch the first and second transistors to connect the first and second gate lines to a fixed voltage during a touch phase, and can switch the first and second transistors to disconnect the first and second gate lines from the fixed voltage during a display phase.

Claims

1. A method of operating a touch screen having drive regions and sense regions, each drive and sense region having a plurality of pixels with common electrodes connected together along first and second directions, the drive and sense regions arranged for permitting touch sensing by capacitive coupling between the drive and sense regions, the method comprising:

during a touch sensing phase in which a touch is sensed, connecting circuit elements of the pixels in at least the drive regions to a predetermined voltage through at least a first conductive pathway and, at substantially the same time, connecting the same circuit elements of the pixels in at least the drive regions to the same predetermined voltage by a second conductive pathway, the second conductive pathway having at least a portion thereof different from the first conductive pathway;

during a display phase in which an image is displayed on the touch screen, disconnecting the circuit elements from the predetermined voltage; and

wherein connecting the circuit elements to the predetermined voltage includes switching a first switching element to connect the circuit elements to the predetermined voltage through the first conductive pathway, and switching a second switching element to connect the circuit elements to the predetermined voltage through the second conductive pathway.

2. The method of claim 1, wherein the first switching element comprises a first transistor and the second switching element comprises a second transistor, and the drive and sense regions are arranged for permitting touch sensing by capacitive coupling between the common electrodes of the drive and sense regions.

3. The method of claim 2, wherein the circuit elements comprise gates of the pixels.

4. The method of claim 3, further comprising:

a first gate line connecting the gates of pixel elements along a first row of the touch screen;

the first transistor has a source or drain connected to the first gate line, the method including controlling display elements of the touch screen along the first row of the touch screen by utilizing the first gate line;

the second transistor has a source or drain connected to the first gate line,

the first transistor having a gate input and the second transistor having a gate input; and

wherein the method includes connecting the first gate line to the predetermined voltage by turning on the first transistor and the second transistor at substantially the same time utilizing their respective gate inputs.

5. The method of claim 4, further comprising:

during the display phase, connecting the circuit elements to a second predetermined voltage; and

during the touch sensing phase connecting the circuit elements of the pixels in the sense regions to the predetermined voltage.

6. The method of claim 5, wherein connecting the first gate line to the predetermined voltage includes switching a third transistor to connect the first gate line to the predetermined voltage through a third conductive pathway, the third conductive pathway having at least portions thereof different from the first and second pathways, the third transistor having a gate input for turning on the third transistor at substantially the same time as turning on the first and second transistors.

7. The method of claim 6, the gate inputs of the second transistor and the third transistor are connected together by a common conductive pathway.

8. The method of claim 6, wherein connecting the first gate line to the predetermined voltage includes switching a fourth transistor to connect the first gate lines to the predetermined voltage through a fourth conductive pathway, the fourth conductive pathway have at least portions thereof different from the first, second and third conductive pathways.

9. The method of claim 1, further comprising:

during the display phase, connecting the circuit elements to a second predetermined voltage; and

during the touch sensing phase connecting the circuit elements of the pixels in the sense regions to the predetermined voltage.

10. The method of claim 1, wherein the circuit elements comprise gates of the pixels.

11. A touch screen having a display phase and a touch phase, the touch screen comprising:

a plurality of drive regions and a plurality of sense regions, each drive and sense region having a plurality of pixels with common electrodes connected together along first and second directions forming rows and columns, the drive and sense regions arranged for permitting touch sensing by capacitive coupling between the common electrodes of the drive and sense regions;

a first transistor with a source or drain connected to a first gate line, the first gate line controlling display elements of the touch screen along a first row of a first drive region of the touch screen, and the first transistor connecting the first gate line to a predetermined voltage during the touch phase;

a second transistor with a source or drain connected to a second gate line, the second gate line controlling display elements of the touch screen along a second row of the first drive region of the touch screen, and the second transistor connecting the second gate line to the predetermined voltage during the touch phase; and

a synchronization line connecting together gates of the first and second transistors during the touch phase such that the first and second transistors shunt the first and second gate lines to the predetermined voltage at the same time.

12. The touch screen of claim 11, further comprising a third transistor connected to the first gate line and a fourth transistor connected to the second gate line, wherein the gates of the third and fourth transistors are disconnected.

13. The touch screen of claim 12 wherein the other of the drain or source of the first and second transistors are connected to the drain or source of the third and fourth transistors respectively.

14. The touch screen of claim 11, wherein the other of the drain or source of the first and second transistors are connected to the predetermined voltage during the touch phase.

15. The touch screen of claim 14, further comprising:

a synchronization system that switches the first and second transistors to connect the first and second gate lines to the predetermined voltage during the touch phase of the touch screen, and that switches the first and second transistors to disconnect the first and second gate lines from the predetermined voltage during a display phase of the touch screen.

16. A touch screen comprising:

a first drive region segment having a plurality of display elements of the touch screen arranged in rows and columns, display elements in the first drive region segment each having a common electrode, and the common electrodes within the first drive region segment connected to one another ;

a second drive region segment having a plurality of display elements of the touch screen arranged in rows and columns, display elements in the second drive region segment each having a common electrode, and the common electrodes within the second drive region segment connected to one another;

a sense region disposed between the first and second drive region segments, the sense region having a plurality of display elements of the touch screen arranged in rows and columns, display elements in the sense region each having a common electrode, and the common electrodes within the sense region connected to one another;

the touch screen operable in a touch phase for sensing touch from capacitive coupling between the common electrodes of the sense region and at least one of the first and second drive region segments when stimulation signals are transmitted through the common electrodes of the display pixels in the first and second drive region segments;

the touch screen operable in a display phase for displaying data using the display elements of the first drive region segment, the second drive region segment and the sense region;

the display elements of the first drive region segment, the second drive region segment and the sense region having gate lines controlling switching transistors associated with the display elements within each of the first drive region segment, the second drive region segment and the sense region; and

a clamping circuit for clamping the gate lines of the display elements within the first drive region segment, the second drive region segment and the sense region to a predetermined voltage during the touch phase through at least a first conductive pathway and a second conductive pathway, the second conductive pathway having at least a portion thereof different from the first conductive pathway.

17. The touch screen of claim 16 wherein the clamping circuit comprises:

a first transistor with a source or drain connected to a first gate line, the first transistor coupling the first gate line to the predetermined voltage through the first conductive path during the touch phase;

a second transistor having a source or drain connected to the first gate line, the second transistor coupling the first gate line to the predetermined voltage through the second conductive pathway during the touch phase.

18. The touch screen of claim 17, further comprising:

a first gate driver for driving the first gate line for display of the data during the display phase;

the first gate driver having third transistor having a source or drain connected to the first gate line, the third transistor coupling the first gate line to the predetermined voltage through a third conductive pathway during the touch phase, the third conductive pathway having at least a portion thereof different from the first and second conductive pathways.

19. The touch screen of claim 18, further comprising a fourth transistor having a source or drain connected to the first gate line, the fourth transistor coupling the first gate line to the predetermined voltage through a fourth conductive pathway during the touch phase. the fourth conductive pathway having at least a portion thereof different from the first, second and third conductive pathways.

20. The touch screen of claim 19 wherein the first and second transistors have gate inputs connected to at least one synchronization line for turn on the first and second transistors during the touch phase.

21. The touch screen of claim 16, further comprising at least one tunnel line connecting the common electrodes of the first drive region segment to the common electrodes of the second drive region segment;

and

wherein the fourth transistor has a gate input connected to the one or more synchoronizaton lines.

22. A touch screen comprising:

a plurality of drive regions and a plurality of sense regions, each drive and sense region having a plurality of pixels with common electrodes connected together along first and second directions forming rows and columns, the drive and sense regions arranged for permitting touch sensing by capacitive coupling between the drive and sense regions;

a first circuit for connecting circuit elements of at least the drive regions of the touch screen to a predetermined voltage through at least a first and second conductive pathway during a touch sensing phase in which a touch is sensed, the second conductive pathway having at least a portion thereof different from the first conductive pathway, the first and second conductive pathways connecting the circuit elements of at least the drive region to the predetermined voltage at substantially the same time;

a second circuit for disconnecting the circuit elements from the predetermined voltage during a display phase in which an image is displayed on the touch screen; and

wherein the first circuit includes a first switching element o connect the circuit elements to the predetermined voltage through the first conductive pathway. and a second switching element to connect the circuit element to the predetermined voltage through the second conductive pathway.

23. The touch screen of claim 22, wherein the first switching element comprises a first transistor and the second switching element comprises a second transistor.

24. The touch screen of claim 22 wherein the circuit elements comprise gates of the pixels in at least the drive regions of the touch screen.

25. The touch screen of claim 24, wherein:

wherein the first circuit includes a first transistor to connect the circuit elements to the predetermined voltage through the first conductive pathway, and a second transistor to connect the circuit element to the predetermined voltage through the second conductive pathway;

the first transistor has a source or drain connected to a first gate line, the first gate line controlling display elements of the touch screen along a first row of the touch screen; and

the second transistor has a source or drain connected to the first gate line;

the first transistor having a gate input and the second transistor having a gate input; and

wherein the gate inputs of the first transistor and the second transistor turn on the first and second transistors at the same time to connect the first gate line to the predetermined voltage.

26. The touch screen of claim 25, wherein a third transistor is switched to connect the first gate line to the predetermined voltage through a third conductive pathway, the third conductive pathway having at least portions thereof different from the first and second pathways, the third transistor having a gate input for turning on the third transistor.

27. The touch screen of claim 26, wherein the gate inputs of the second transistor and the third transistor are connected together by a common conductive pathway.

28. The touch screen of claim 27, wherein a fourth transistor is switched to connect the circuit elements to the predetermined voltage through a fourth conductive pathway, the fourth conductive pathway have at least portions thereof different from the first, second and third conductive pathways.