Simultaneous sensing arrangement

• US 8,928,617 B2
• Filed: 09/05/2013
• Issued: 01/06/2015
• Est. Priority Date: 01/03/2007
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven P., Elias, John Greer, Sakariya, Kapil Vinod
• Primary Examiner(s): MARINELLI, PATRICK
• Application Number:
  US14/019,264
• Publication Number:
  US 20140168143A1
• Time in Patent Office: 488 Days
• Field of Search: 345156-184, 178 1801- 2004
• US Class Current: 345/173
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 1/3265 Power saving in display device
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• 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 3/0416 Control or interface arrangements specially adapted for digitisers
• 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 3/041661 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 3/044 by capacitive means
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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
• CPC Class Codes: G06F 3/047 using sets of wires, e.g. crossed wires

Abstract

Multi-touch touch-sensing devices and methods are described herein. The touch sensing devices can include multiple sense points, each located at a crossing of a drive line and a sense line. In some embodiments, multiple drive lines may be simultaneously or nearly simultaneously stimulated with drive signals having unique characteristics, such as phase or frequency. A sense signal can occur on each sense line that can be related to the drive signals by an amount of touch present at sense points corresponding to the stimulated drive lines and the sense line. By using processing techniques based on the unique drive signals, an amount of touch corresponding to each sense point can be extracted from the sense signal. The touch sensing methods and devices can be incorporated into interfaces for a variety of electronic devices such as a desktop, tablet, notebook, and handheld computers, personal digital assistants, media players, and mobile telephones.

Claims

1. A method of driving a touch sensitive surface, the touch sensitive surface comprising a plurality of sensing points, each sensing point being associated with at least one of a plurality of drive lines and at least one of a plurality of sense lines, the method comprising:

simultaneously stimulating two or more drive lines of the plurality of drive lines during a plurality of time periods such that a net DC component of the two or more drive lines being stimulated during any one of the plurality of time periods is zero volts.

2. The method of claim 1, wherein the method further includes simultaneously stimulating two or more drive lines of the plurality of drivelines during the plurality of time periods such that the net DC component of any one of the drive lines of the two or more drive lines being stimulated after all of the plurality of time periods have elapsed is zero volts.

3. The method of claim 1, the method further comprising:

sensing a sense signal on at least one sense line, wherein the sense signal is related to the drive signals by touch or proximity of one or more objects to one or more sensing points associated with at least one of the two drive lines and the at least one sense line; and

deriving touch information from the sense signal, wherein deriving touch information from the sense signal comprises;

deriving a plurality of values from the sense signal; and

deriving touch information from a mathematical combination of the plurality of values.

4. The method of claim 3 wherein deriving a plurality of values from the sense signal comprises integrating the sense signal over time.

5. The method of claim 4 wherein the plurality of values from the sense signal values include a capacitance measurement.

6. The method of claim 1 wherein the plurality of drive lines are simultaneously stimulated during the plurality of time periods with drive signals of the same frequency, wherein a first half of the two or more drive signals are out of phase with a second half of the two or more drive signals during at least one of the plurality of time periods.

7. The method of claim 1 wherein a predetermined phase relationship of the drive signals is selected to eliminate a DC component of the sense signal.

8. A touch sensing device comprising:

a touch sensitive surface having a plurality of sensing points, each sensing point being associated with one of a plurality of drive lines and one of a plurality of sense lines;

drive circuitry that applies drive signals simultaneously to two or more of the plurality of drive lines during a plurality of time periods such that a net DC component of the two or more drive lines being stimulated during any one of the plurality of time periods is zero volts;

sense circuitry that detects a sense signal in at least one sense line, the sense signal being related to the drive signals by touch or proximity of one or more objects to one or more sensing points associated with the sense line, and derives touch information for the one or more sensing points from the sense signal.

9. The touch sensing device of claim 8, wherein applying drive signals simultaneous to two or more of the plurality of drive lines further includes simultaneously stimulating two or more drive lines of the plurality of drivelines during the plurality of time periods such that the net DC component of any one of the drive lines of the two or more drive lines being stimulated after all of the plurality of time periods have elapsed is zero volts.

10. The touch sensing device of claim 8 wherein the sense circuitry comprises at least one microcontroller.

11. The touch sensing device of claim 10 wherein the at least one microcontroller is an application specific integrated circuit (ASIC).

12. The touch sensing device of claim 10 wherein the at least one microcontroller is a digital signal processor (DSP).

13. The touch sensing device of claim 8 wherein the sense circuitry derives touch information from the sense signal by deriving a plurality of values from the sense signal and deriving touch information from a mathematical combination of the plurality of values.

14. The touch sensing device of claim 13 wherein the sense circuitry derives a plurality of values from the sense signal by integrating the sense signal over time.

15. The touch sensing device of claim 8 wherein the touch sensitive surface is based on mutual capacitance.

16. The touch sensing device of claim 15 wherein the touch information comprises an array of touch values at each sensing point.

17. The touch sensing device of claim 16 wherein the touch values correspond to a capacitance measurement at each sensing point.

18. The touch sensing device of claim 8 wherein drive signals are simultaneously applied to four drive lines during the plurality of time periods, wherein, in the predetermined phase relationship, the drive signals have the same frequency and a first pair of the drive signals are out of phase with a second pair of the drive signals during at least one of the plurality of time periods.

19. The touch sensing device of claim 8 wherein the predetermined phase relationship is selected to eliminate a DC component of the sense signal.

20. The touch sensing device of claim 8 wherein the touch sensitive surface is part of a touch screen.