Power efficient capacitive detection

• US 8,169,419 B2
• Filed: 08/10/2010
• Issued: 05/01/2012
• Est. Priority Date: 08/13/2007
• Status: Active Grant

• Current Assignee: Nuvoton Technology Corporation (Winbond Electronics Corporation)
• Original Assignee: Nuvoton Technology Corporation (Winbond Electronics Corporation)
• Inventors: Tasher, Nir, Abramov, Vladimir, Friedman, Yehezkel, Nosovitsky, Einat, Lukoyanichev, Mark
• Primary Examiner(s): OSORIO, RICARDO
• Application Number:
  US12/853,570
• Publication Number:
  US 20100302198A1
• Time in Patent Office: 630 Days
• Field of Search: 345/156, 345/173, 341/20, 341/22, 341/23
• US Class Current: 345/174
• CPC Class Codes: G01D 5/2405 by varying dielectric
• 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 3/0443 using a single layer of sensing electrodes

Abstract

Capacitive detection systems, modules, and methods. In one embodiment, a power saving mode is implemented when deemed appropriate, based on an analysis of previous detection or non-detection of the presence and/or position of an object near a capacitive sensing area.

Claims

1. A capacitive detection method, comprising:

receiving data corresponding to a plurality of capacitive sensors in a capacitive sensing area;

using said received data or a function thereof to detect a position of an object whose presence has been detected as touching said input device;

determining whether a difference in said detected position or a function thereof from a preceding detected position or a function thereof is below a predetermined amount; and

if said difference is determined to be below said predetermined amount, causing a subsequent attempt for detecting whether an object is present to consume less power, than if said difference had been determined to not be below said predetermined amount.

2. The method of claim 1, wherein said difference equals a vector between said preceding filtered or unfiltered position and said detected filtered or unfiltered position.

3. The method of claim 1, wherein said difference equals a change in filtered or unfiltered position divided by elapsed time between a time of preceding detection of position and a time of said detection of position.

4. The method of claim 1, wherein said causing includes:

causing said subsequent attempt to occur at a later time than if said difference had been determined to not be below said predetermined amount.

5. The method of claim 4, wherein said causing includes:

causing charging and discharging of at least one capacitive sensor in said capacitive sensing area in said subsequent attempt to occur at a later time than if said difference had been determined to not be below said predetermined amount.

6. The method of claim 4, wherein said causing includes:

in said subsequent attempt, receiving data corresponding to at least one capacitive sensor in said capacitive sensing area, or processing said received data, at a later time than if said difference had been determined to not be below said predetermined amount.

7. The method of claim 1, wherein said causing includes:

causing data corresponding to at least one capacitive sensor in said capacitive sensing area which is received in said subsequent attempt to be of a lower value than if said difference had been determined to not be below said predetermined amount.

8. The method of claim 1, wherein said causing includes:

causing less capacitive sensors in said capacitive sensing area to be charged and discharged during said subsequent attempt, than if said difference had been determined to not be below said predetermined amount.

9. The method of claim 1, further comprising:

if said difference is determined to not be below said predetermined amount, causing a subsequent attempt for detecting whether an object is present to consume more power, than if said difference had been determined to be below said predetermined amount.

10. A controller module comprising:

an interaction module configured to receive data corresponding to a plurality of capacitive sensors in a capacitive sensing area;

a position detection module configured to detect position of an object near said capacitive sensing area based on said received data or a function thereof; and

means for determining whether a difference in said detected position or a function thereof from a preceding detected position or a function thereof is below a predetermined amount;

said interaction module being configured, depending on whether or not said difference is below a predetermined amount, to configure, if not already configured, a power saving mode or a normal mode.

11. The module of claim 10, wherein said power saving mode reduces a number of sensors for which data is subsequently received compared to said normal mode.

12. The module of claim 10, wherein for at least one sensor in said capacitive sensing area said power saving mode reduces a value of data subsequently received compared to said normal mode.

13. The module of claim 10, wherein said power saving mode reduces a frequency of subsequent generation, receipt, or processing of data corresponding to at least one sensor in said capacitive sensing area, compared to said normal mode.

14. The module of claim 10, wherein said means includes an offset module configured to provide a filtered detected position.

15. A capacitive detection computer program product comprising a computer useable medium having computer readable program code embodied therein, the computer program product comprising:

computer readable program code for causing the computer to receive data corresponding to a plurality of capacitive sensors in a capacitive sensing area;

computer readable program code for causing the computer to use said received data or a function thereof to detect a position of an object whose presence has been detected as touching said input device;

computer readable program code for causing the computer to determine whether a difference in said detected position or a function thereof from a preceding detected position or a function thereof is below a predetermined amount; and

computer readable program code for causing the computer, if said difference is determined to be below said predetermined amount, to cause a subsequent attempt for detecting whether an object is present to consume less power, than if said difference had been determined to not be below said predetermined amount.