SIMULTANEOUS SENSING ARRANGEMENT

• US 20140375612A1
• Filed: 09/10/2014
• Published: 12/25/2014
• 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
• Granted Patent: US 9,552,115 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• 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 stimulating a touch sensitive surface, the touch sensitive surface comprising a plurality of sensing points, a 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:

stimulating a first drive line of the plurality of drive lines with a first drive signal during a first time period; and

stimulating a second drive line of the plurality of drive lines with a second drive signal during a second time period, the second time period at least partially overlapping the first time period during an overlapping time period;

wherein the first and second drive signals have the same frequency and are in phase during a first portion of the overlapping time period and out of phase during a second portion of the overlapping time period.

2. 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 first and second drive signals by touch or proximity of one or more objects to one or more sensing points associated with at least one of the first and second 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.

3. The method of claim 2, wherein deriving touch information from the sense signal comprises integrating the sense signal over time.

4. The method of claim 2, wherein the plurality of values from the sense signal include a capacitance measurement.

5. The method of claim 1, further comprising:

stimulating a third drive line of the plurality of drive lines with a third drive signal during a third time period; and

stimulating a fourth drive line of the plurality of drive lines with a fourth drive signal during a fourth time period, the first, second, third and fourth time periods at least partially overlapping during the overlapping time period;

wherein the first, second, third and fourth drive signals have the same frequency and two of the first, second, third and fourth drive signals are out of phase with another two of the first, second, third and fourth drive signals during a third portion of the overlapping time period.

6. The method of claim 5, wherein the first, second, third and fourth drive signals are in phase during a fourth portion of the overlapping time period.

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

8. A touch sensing device comprising:

drive circuitry configured to;

apply a first drive signal to a first drive line of a plurality of drive lines during a first time period; and

apply a second drive signal to a second drive line of the plurality of drive lines during a second time period, the second time period at least partially overlapping the first time period during an overlapping time period, wherein the first and second drive signals have the same frequency and are in phase during a first portion of the overlapping time period and out of phase during a second portion of the overlapping time period; and

sense circuitry configured to;

detect a sense signal from at least one sense line, the sense signal being related to the first and second drive signals by touch or proximity of one or more objects to one or more sensing points associated with the at least one sense line, a sensing point being associated with at least one of the plurality of drive lines and at least one of a plurality of sense lines; and

derive touch information for the one or more sensing points from the sense signal.

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

10. The touch sensing device of claim 9, wherein the at least one microcontroller is an application specific integrated circuit (ASIC).

11. The touch sensing device of claim 9, wherein the at least one microcontroller is a digital signal processor (DSP).

12. 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.

13. The touch sensing device of claim 12, wherein the sense circuitry derives a plurality of values from the sense signal by integrating the sense signal over time.

14. The touch sensing device of claim 12, wherein the plurality of values correspond to a capacitance measurement at a plurality of sensing points.

15. The touch sensing device of claim 8, the drive circuitry further configured to:

apply a third drive signal to a third drive line of the plurality of drive lines during a third time period; and

apply a fourth drive signal to a fourth drive line of the plurality of drive lines during a fourth time period, the first, second, third and fourth time periods at least partially overlapping during the overlapping time period;

wherein the first, second, third and fourth drive signals have the same frequency and two of the first, second, third and fourth drive signals are out of phase with another two of the first, second, third and fourth drive signal during a third portion of the overlapping time period.

16. The touch sensing device of claim 8 wherein a phase relationship between the first and second drive lines during the overlapping time period is selected to eliminate a DC component of the sense signal.

17. The touch sensing device of claim 8, wherein the plurality of drive lines and the plurality of sense lines are part of a touch screen.

18. A method of deriving touch information from a touch sensitive surface, the touch sensitive surface comprising a plurality of sensing points, a sensing point being located at a crossing of a drive line and a sense line, the method comprising:

performing a coarse scan of a first region of the touch sensitive surface to determine whether a touch is present within the first region, the first region corresponding to a first plurality of drive lines;

when a touch is present in the first region, performing a fine scan of the first region; and

when a touch is not present in the first region, performing a coarse scan of a second region of the touch sensitive surface, wherein the second region corresponds to a second plurality of drive lines.

19. The method of claim 18, wherein performing a coarse scan of a region comprises:

simultaneously stimulating a plurality of drive lines with one or more first drive signals;

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

determining whether a touch is present with the region.

20. The method of claim 19, wherein the one or more first drive signals have the same frequency and phase.

21. The method of claim 19, wherein determining whether a touch is present within the region comprises examining the DC content of the sense signal.

22. The method of claim 18, wherein performing a fine scan of a region comprises:

further simultaneously stimulating the plurality of drive lines with a plurality of second drive signals;

further sensing a sense signal on at least one sense line, wherein the sense signal is related to the second plurality of drive signals by touch or proximity of one or more objects to one or more sensing points located at a crossing of the plurality of drive lines and the at least one sense line; and

deriving fine touch information from the sense signal.

23. The method of claim 22, wherein the plurality of second drive signals have the same frequency and a first half of the plurality of second drive signals are out of phase with a second half of the plurality of second drive signals.

24. A touch sensing device comprising:

drive circuitry configured to;

perform a coarse scan of a first region of the touch sensitive surface to determine whether a touch is present within the first region, the first region corresponding to a first plurality of drive lines;

perform a fine scan of the first region when a touch is present in the first region during the course scan; and

perform a coarse scan of a second region of the touch sensitive surface when a touch is not present in the first region, wherein the second region corresponds to a second plurality of drive lines.

25. The touch sensing device of claim 24, wherein the first plurality of drive lines is stimulated with first drive signals that are in phase during a coarse scan and stimulated with second drive signals with a first half of the second drive signals out of phase with a second half of the second drive signals during at least a portion of a fine scan.