Touch and hover switching

• US 9,268,431 B2
• Filed: 09/30/2010
• Issued: 02/23/2016
• Est. Priority Date: 08/27/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: King, Brian Michael, Puskarich, Paul G., Bernstein, Jeffrey Traer, Mucignat, Andrea, Cieplinski, Avi E., Choudry, Muhammad U., Subramani, Praveen R., Piche, Marc J., Amm, David T., Kerr, Duncan Robert, Leung, Omar
• Primary Examiner(s): Chang, Kent
• Assistant Examiner(s): Lu, William
• Application Number:
  US12/895,643
• Publication Number:
  US 20120050180A1
• Time in Patent Office: 1,972 Days
• Field of Search: 345156-184
• US Class Current: 1/1
• 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 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04108 Touchless 2D- 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 without distance measurement in the Z direction
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• 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 3/041662 using alternate mutual and self-capacitive scanning
• 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

Abstract

Touch and hover switching is disclosed. A touch and hover sensing device can switch between a touch mode and a hover mode. During a touch mode, the device can be switched to sense one or more objects touching the device. During a hover mode, the device can be switched to sense one or more objects hovering over the device. The device can include a panel having multiple sensors for sensing a touching object and/or a hovering object and a touch and hover control system for switching the device between the touch and hover modes. The device'"'"'s touch and hover control system can include a touch sensing circuit for coupling to the sensors to measure a capacitance indicative of a touching object during the touch mode, a hover sensing circuit for coupling to the sensors to measure a capacitance indicative of a hovering object during the hover mode, and a switching mechanism for switching the sensors to couple to either the touch sensing circuit or the hover sensing circuit. The device can switch modes based on a condition of the device, such as an expiration of a timer or a relative distance of an object from the panel.

Claims

1. A capacitive sensing device comprising:

a control system configured to control switching between a mutual capacitance mode and a self-capacitance mode, wherein;

the control system comprises;

a mutual capacitance sensing circuit configured to measure mutual capacitance at the sensing device,

a self-capacitance sensing circuit configured to measure self-capacitance at the sensing device, and

a switching mechanism configured to couple at least one sensor capable of detecting mutual capacitance or self-capacitance to either the mutual capacitance sensing circuit or the self-capacitance sensing circuit, the switching mechanism coupling the at least one sensor to the mutual capacitance sensing circuit during the mutual capacitance mode and to the self-capacitance sensing circuit during the self-capacitance mode, and

the control system is configured to;

measure a first capacitance at the sensing device using the at least one sensor, the first capacitance indicative of an object proximate to the device,

in accordance with a determination that the first capacitance is greater than a first threshold associated with the mutual capacitance mode, operate the sensing device in the mutual capacitance mode,

in accordance with a determination that the first capacitance is less than a second threshold associated with the self-capacitance mode, operate the sensing device in the self-capacitance mode, and

in accordance with a determination that the first capacitance is less than the first threshold and greater than the second threshold, alternate operation of the sensing device between the mutual capacitance mode and the self-capacitance mode.

2. The device of claim 1, wherein the switching mechanism is a switch.

3. The device of claim 1, wherein the control system further comprises a controller configured to control the switching mechanism, the controller sending a control signal to the switching mechanism to actuate the switching mechanism.

4. The device of claim 1, wherein the self-capacitance sensing circuit comprises a gain amplifier for sensing the self-capacitance at the sensing device, the gain amplifier coupling to the at least one sensor through a first connection to receive the self-capacitance measurement, and to a reference voltage source through a second connection to receive a reference signal, the gain amplifier subtracting the reference signal from the self-capacitance measurement so as to output a signal compensated for parasitic capacitance at the switching mechanism.

5. The device of claim 1, wherein the control system further comprises a capacitor disposed between the at least one sensor and the switching mechanism so as to compensate the self-capacitance measurement at the sensing device for parasitic capacitance at the switching mechanism.

6. The device of claim 1, wherein the switching mechanism is a controller configured to send control signals to the mutual capacitance sensing circuit and the self-capacitance sensing circuit to switch between the sensing circuits.

7. The device of claim 6, wherein, during the mutual capacitance mode, the controller sends an enable signal to the mutual capacitance sensing circuit to enable the mutual capacitance sensing circuit and a disable signal to the self-capacitance sensing circuit to disable the self-capacitance sensing circuit, and, during the self-capacitance mode, the controller sends a disable signal to the mutual capacitance sensing circuit to disable the mutual capacitance sensing circuit and an enable signal to the self-capacitance sensing circuit to enable the self-capacitance sensing circuit.

8. The device of claim 1, wherein the first and second thresholds are indicative of relative distances from the sensing device of the object proximate to the device.

9. The device of claim 1, wherein the control system measures self-capacitance at the at least one sensor during the self-capacitance mode.

10. The device of claim 1, wherein the control system measures mutual capacitance at the at least one sensor during the mutual capacitance mode.

11. The device of claim 1, wherein

the first threshold is indicative of an object touching the sensing device and the second threshold is indicative of an object hovering over the sensing device.

12. A method of switching between a mutual capacitance sensing mode and a self-capacitance sensing mode of a sensing device, the method comprising:

measuring a first capacitance at the sensing device using at least one sensor, the first capacitance indicative of an object proximate to the device, and the at least one sensor configured to be used in both the mutual capacitance and self-capacitance sensing modes;

in accordance with a determination that the first capacitance is greater than a first threshold associated with the mutual capacitance sensing mode, operating the sensing device in the mutual capacitance sensing mode,

in accordance with a determination that the first capacitance is less than a second threshold associated with the self-capacitance sensing mode, operating the sensing device in the self-capacitance sensing mode, and

in accordance with a determination that the first capacitance is less than the first threshold and greater than the second threshold, alternating operation of the sensing device between the mutual capacitance sensing mode and the self-capacitance sensing mode.

13. The method of claim 12,

wherein the first threshold is indicative of an object touching the sensing device and the second threshold is indicative of an object hovering over the sensing device.

14. The method of claim 12, wherein the first threshold is higher than the second threshold.

15. The method of claim 12, wherein the mutual capacitance sensing mode is a touch mode to detect an object touching the device.

16. The method of claim 12, wherein the self-capacitance sensing mode is a hover mode to detect an object hovering over the device.

17. A capacitive sensing device comprising:

a sensing panel having multiple sensors, each capable of detecting mutual capacitance or self-capacitance and configured to detect one or more objects proximate to the panel; and

a control system configured to measure capacitance associated with the proximate objects and to switch the sensors between a mutual capacitance detection mode and a self-capacitance detection mode, wherein the control system is configured to;

measure a first capacitance at the sensing device using the sensors, the first capacitance indicative of the one or more objects proximate to the panel,

in accordance with a determination that the first capacitance is greater than a first threshold associated with the mutual capacitance detection mode, operate the sensing device in the mutual capacitance detection mode,

in accordance with a determination that the first capacitance is less than a second threshold associated with the self-capacitance detection mode, operate the sensing device in the self-capacitance detection mode, and

in accordance with a determination that the first capacitance is less than the first threshold and greater than the second threshold, alternate operation of the sensing device between the mutual capacitance detection mode and the self-capacitance detection mode.

18. The device of claim 17, wherein the control system switches a portion of the sensors to the mutual capacitance detection mode and another portion of the sensors to the self-capacitance detection mode so as to partition the panel to concurrently detect mutual capacitance and self-capacitance at the panel.

19. The device of claim 17, further comprising a display configured to display graphical information to select in response to the one or more objects proximate to the panel.

20. The device of claim 17 incorporated into at least one of a mobile phone, a digital media player, or a computer.

21. The device of claim 17, wherein

the first threshold is indicative of an object touching the sensing device and the second threshold is indicative of an object hovering over the sensing device.