Integrated button activation sensing and proximity sensing

• US 8,860,683 B2
• Filed: 06/26/2007
• Issued: 10/14/2014
• Est. Priority Date: 04/05/2007
• Status: Expired due to Fees

• Current Assignee: Monterey Research, LLC (Vector Capital Corporation)
• Original Assignee: Cypress Semiconductor Corporation (Infineon Technologies AG)
• Inventors: Baumbach, Jason G.
• Primary Examiner(s): OLSON, JASON C
• Application Number:
  US11/823,361
• Publication Number:
  US 20080246723A1
• Time in Patent Office: 2,667 Days
• Field of Search: None
• US Class Current: 345/174
• CPC Class Codes: G06F 3/03547 Touch pads, in which fingers can move on a surface
• CPC Class Codes: G06F 3/0442 using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/94026 Automatic threshold calibration; e.g. threshold automatically adapts to ambient conditions or follows variation of input

Abstract

Apparatuses and methods for coupling a group of sensor elements together in one mode to collectively measure a capacitance on the group of sensor elements, in addition to individually measuring a capacitance on each of the sensor elements in another mode. The touch-sensor buttons may be used individually for button-activation sensing, and the touch-sensor buttons may be used collectively for proximity detection. The touch-sensor buttons and a ground conductor that surrounds the touch-sensor buttons may also be collectively used for proximity detection. The apparatus may include a processing device, and a plurality of sensor elements that are individually coupled in a first mode for button-activation sensing and collectively coupled in a second mode for proximity sensing.

Claims

1. A method, comprising:

detecting a presence of a conductive object on a device by individually measuring a capacitance for each of a plurality of sensor elements of the device;

coupling a group of sensor elements of the plurality of sensor elements together;

conductively coupling a ground conductor to the group of coupled sensor elements; and

measuring a single collective capacitance for the group of coupled sensor elements to detect a presence of the conductive object in proximity to the device by applying a signal to the group of coupled sensor elements while the group of coupled sensor elements is conductively coupled with the ground conductor.

2. The method of claim 1, further comprising:

coupling the group of coupled sensor elements and the ground conductor to a processing device while collectively measuring the capacitance on the group of coupled sensor elements to detect the presence of the conductive object in proximity to the device; and

coupling the ground conductor to a ground of the processing device while individually measuring the capacitance on each of the plurality of sensor elements to detect the presence of the conductive object on the device.

3. The method of claim 2, further comprising determining activation of a first sensor element of the plurality of sensor elements when the presence of the conductive object is detected on the first sensor element of the device.

4. The method of claim 3, further comprising:

determining a button activation when the conductive object is detected on the first sensor element using the individual capacitance measured on the first sensor element;

determining a proximity event when the conductive object is detected in proximity to the device using the collective capacitance on the group of coupled sensor elements and the ground conductor;

performing a first operation upon determining the proximity event; and

performing a second operation upon determining the button activation.

5. The method of claim 4, wherein performing the first operation comprises activating a display, and wherein performing the second operation comprises performing a button operation.

6. The method of claim 4, wherein determining the proximity event comprises:

performing a first baseline measurement on the group of sensor elements while the group of sensor elements are coupled together, wherein the first baseline measurement is representative of the capacitance on the group of coupled sensor elements while a conductive object is not in proximity to the device; and

comparing the capacitance measured on the group of coupled sensor elements with the first baseline measurement on the group of coupled sensor elements while the group of sensor elements are coupled together, wherein the proximity event is determined when the capacitance measured on the group of coupled sensor elements is greater than the first baseline measurement, and wherein determining the button activation comprises;

performing a baseline measurement on each of the plurality of sensor elements while the plurality of sensor elements are not coupled together, wherein the baseline measurements of each of the plurality of sensor elements are representative of the capacitance on each of the plurality of sensor elements while a conductive object is not present on the device; and

comparing the capacitances on each of the plurality of sensor elements with the baseline measurements on each of the plurality of sensor elements while the plurality of sensor elements are not coupled together, wherein the button activation is determined when the capacitance on the first sensor element is greater than the respective baseline measurement of the first sensor element.

7. The method of claim 1, wherein collectively measuring the capacitance on the group of coupled sensor elements is performed in a first mode, and wherein individually measuring the capacitance on each of the plurality of sensor elements is performed in a second mode, and wherein the method further comprises:

transitioning from the first mode to the second mode when the presence of the conductive object is detected in proximity to the device in the first mode; and

transitioning from the second mode to the first mode when the presence of the conductive object is not detected on the device for a period of time.

8. The method of claim 1, wherein coupling the group of sensor elements comprises at least one of coupling all of the plurality of sensor elements together as the group of sensor elements or coupling a fraction of the plurality of sensor elements together as the group of sensor elements.

9. The method of claim 1, wherein coupling the group of sensor elements comprises coupling the group of sensor elements as a first group of coupled sensor elements in a first zone of the device, and wherein the method further comprises:

coupling a second group of sensor elements of the plurality of sensor elements together in a second zone of the device;

collectively measuring a capacitance on each of the first and second groups of coupled sensor elements;

determining a first proximity event when the conductive object is detected in proximity to the first zone of the device using the collective capacitance on the first group of coupled sensor elements;

determining a second proximity event when the conductive object is detected in proximity to the second zone of the device using the collective capacitance on the second group of coupled sensor elements; and

determining a button activation when the conductive object is detected on a first sensor element of the plurality of sensor elements using the individual capacitance measured on the first sensor element.

10. The method of claim 9, further comprising:

performing a first operation upon determining the first proximity event;

performing a second operation upon determining the second proximity event; and

performing a third operation upon determining the button activation.

11. The method of claim 10, wherein performing the first operation comprises activating a first portion of a display, wherein performing the second operation comprises activating a second portion of the display, and wherein performing the third operation comprises performing a button operation.

12. An apparatus, comprising:

a plurality of sensor elements;

a processing device, wherein the plurality of sensor elements are individually coupled to the processing device to detect a presence of a conductive object on the apparatus, and wherein a group of sensor elements of the plurality of sensor elements are collectively coupled to the processing device while the processing device is configured to apply a signal to the collectively coupled group of sensor elements to measure a single collective capacitance for the group of sensor elements and to detect a presence of a conductive object in proximity to the apparatus; and

a ground conductor, wherein the ground conductor is conductively coupled to the group of coupled sensor elements when the processing device is configured to detect the presence of the conductive object in proximity to the apparatus.

13. The apparatus of claim 12, wherein the ground conductor is coupled to a ground of the processing device when the processing device is configured to detect the presence of the conductive object on the apparatus.

14. The apparatus of claim 13, wherein the ground conductor is a ground plane disposed to surround each of the plurality of sensor elements.

15. The apparatus of claim 13, wherein the ground conductor is conductive material of a housing of the apparatus.

16. The apparatus of claim 13, further comprising a selection circuit coupled the processing device, wherein the selection circuit is configured to individually couple the processing device to each of the plurality of sensor elements in a first mode and to collectively couple the processing device to the group of sensor elements and the ground conductor in a second mode.

17. The apparatus of claim 16, wherein the group of sensor elements comprises all of the plurality of sensor elements or a fraction of all of the plurality of sensor elements.

18. The apparatus of claim 16, wherein the processing device is configured to perform a single capacitance measurement on the group of sensor elements during each sensing interval when in the second mode, and wherein the processing device is configured to perform a capacitance measurement on each of the plurality of sensor elements during each sensing interval when in the first mode.

19. The apparatus of claim 12, wherein the processing device is configured to determine a button activation when the conductive object is detected on a first sensor element of the plurality of sensor elements, and wherein the processing device is configured to determine a proximity event when the conductive object is detected in proximity to the apparatus.

20. The apparatus of claim 19, wherein each of the plurality of sensor elements corresponds to a button on a touch panel display, wherein the touch panel display is activated when the proximity event is detected, and wherein the processing device is configured to perform a button operation that corresponds to the button that has been activated.

21. The apparatus of claim 12, wherein the processing device and the plurality of sensor elements reside in a remote control device, and wherein each of the plurality of sensor elements correspond to a button on the remote control device.

22. The apparatus of claim 12, wherein the processing device and the plurality of sensor elements reside in at least one of a touch panel of a plurality of touch-sensor buttons, a touch-sensor slider, or a touch-sensor pad.

23. An apparatus, comprising:

a plurality of sensor elements of a device;

means for detecting a presence of a conductive object both on the device and in proximity to the device based on applying a signal to the group of coupled sensor elements to measure a single collective capacitance for the plurality of sensor elements and without using an additional proximity sensor; and

means for conductively coupling a ground conductor to the group of coupled sensor elements to detect the presence of the conductive object in proximity to the device.

24. The apparatus of claim 23, further comprising means for coupling a group of sensor elements of the plurality of sensor elements together, and wherein the means for detecting comprise:

means for detecting the presence of the conductive object in proximity to the device while the group of sensor elements are coupled together; and

means for detecting the presence of the conductive object on the device while the plurality of sensor elements are not coupled together.

25. The apparatus of claim 23, further comprising means for reducing power consumption of the apparatus.