TOUCH-DISPLAY CROSSTALK

• US 20110298727A1
• Filed: 09/07/2010
• Published: 12/08/2011
• 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.
• Granted Patent: US 9,335,870 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• 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 clamping a circuit element of a touch screen to a predetermined voltage, the method comprising:

during a touch sensing phase in which a touch is sensed, connecting the circuit element to a first source of the predetermined voltage; and

during a display phase in which an image is displayed on the touch screen, disconnecting the circuit element from the first source of the predetermined voltage.

2. The method of claim 1, further comprising concurrently connecting a plurality of circuit elements to a plurality of first sources of the predetermined voltage.

3. The method of claim 1, wherein the circuit element is a circuit element of a display system that displays the image.

4. The method of claim 3, wherein the circuit element is a gate line of the display system, the gate line being connected to gates of transistors in a plurality of display pixels of the touch screen.

5. The method of claim 1, further comprising:

during the display phase, connecting the circuit element to a second source of the predetermined voltage.

6. The method of claim 5, wherein connecting the circuit element to the first source includes switching a first transistor to connect the circuit element to the first source, and connecting the circuit element to the second source includes switching a second transistor to connect the circuit element to the second source.

7. The method of claim 6, wherein the first and second sources include different conductive pathways connected to a single voltage source at the predetermined voltage.

8. The method of claim 7, wherein the first source includes a first conductive line connecting a source or drain of the first transistor to a first voltage line at the predetermined voltage, and the second source includes a second conductive line connecting a source or drain of the second transistor to the first voltage line.

9. The method of claim 5, further comprising:

during the touch sensing phase, connecting the circuit element to the second source.

10. A gate line system of a touch screen, the gate line system comprising:

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.

11. The gate line system of claim 10, wherein the common conductive pathway consists of a fixed line of conductive material.

12. The gate line system of claim 10, 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 gate line system 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.

14. The gate line system of claim 10, wherein the other of the drain or source of the first and second transistors are connected to a predetermined voltage.

15. The gate line system 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 a 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.