Priority and Combination Suppression Techniques (PST/CST) for a Capacitive Keyboard

• US 20080007434A1
• Filed: 05/18/2007
• Published: 01/10/2008
• Est. Priority Date: 07/10/2006
• Status: Active Grant

• Current Assignee: Neodrón Limited (Atlantic IP Services Limited)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Hristov, Luben
• Granted Patent: US 8,786,554 B2
• Time in Patent Office: Days
• US Class Current: 341/22
• CPC Class Codes: G06F 3/0237 using prediction or retrieval techniques
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04886 by partitioning the display area of the touch-screen or the surface of the digitising tablet into independently controllable areas, e.g. virtual keyboards or menus
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard

Abstract

Apparatus and methods are described for selecting which of a plurality of simultaneously activated keys in a keyboard based on an array of capacitive sensors is a key intended for selection by a user. Combinations of keys which are commonly activated simultaneously when a user intends to select a single key are identified and associated with the single keys most likely to give rise to the identified combinations during normal use of the keyboard. In use, an observed combination of simultaneously activated keys is compared with predefined combinations of keys corresponding to those identified as being commonly activated simultaneously. If the combination of activated keys matches one of the predefined combinations, the most likely intended key associated with the matched one of the predefined combination of keys is taken to be most likely intended key.

Claims

1. A touch-sensitive user interface, comprising:

a plurality of sensing areas;

a measurement circuit coupled to the sensing areas and operable to generate output signals indicative of a coupling between a pointing object and respective ones of the sensing areas; and

a controller operable to receive the output signals from the measurement circuit, to determine from the output signals a combination of the sensing areas which are activated by the presence of the pointing object, to compare the combination of activated sensing areas with at least one predefined combination of the sensing areas, and to determine a selected one of the sensing areas according to a correspondence between the combination of activated sensing areas and a one of the at least one predefined combinations of sensing areas.

2. A touch-sensitive user interface according to claim 1, wherein the coupling is a capacitive coupling.

3. A touch-sensitive user interface according to claim 1, wherein the plurality of sensing areas comprises between three and six sensing areas.

4. A touch-sensitive user interface according to claim 3, wherein the plurality of sensing areas comprises four sensing areas.

5. A touch sensitive user interface according to claim 1, wherein the combination of activated sensing areas comprises three sensing areas arranged along a line, and the selected one of the activated sensing areas is a middle one of the activated sensing areas.

6. A touch sensitive user interface according to claim 5, wherein the line corresponds with a direction of approach and/or extent of a pointing object during normal use.

7. A touch sensitive user interface according to claim 1, wherein the combination of activated sensing areas comprises four sensing areas arranged in a line and the selected one of the activated sensing areas is adjacent to a sensing area at an end of the line of activated sensing areas.

8. A touch sensitive user interface according to claim 7, wherein the line corresponds with a direction of approach and/or extent of a pointing object during normal use, and the selected one of the activated sensing areas is the second most distant activated sensing area along and relative to the direction of approach and/or extent of the pointing object during normal use.

9. A touch sensitive user interface according to claim 1, wherein the at least one predefined combination of activated sensing areas comprises a contiguous series of neighboring sensing areas.

10. A touch sensitive user interface according to claim 1, wherein the at least one predefined combination of sensing areas comprises at least three sensing areas.

11. A touch sensitive user interface according to claim 1, wherein each sensing area has a position within the sensing region, and wherein if the comparison of the combination of activated sensing areas with the at least one predefined combination of sensing areas does not reveal a correspondence, the controller is operable to determine a selected one of the activated sensing areas by taking account of the positions of the activated sensing areas within the sensing region.

12. A touch sensitive user interface according to claim 1, wherein if the comparison of the combination of activated sensing areas with the at least one predefined combination of sensing areas does not reveal a correspondence, the controller is operable to determine a selected one of the activated sensing areas by taking account of the output signals associated with the sensing areas.

13. A touch-sensitive user interface according to claim 1, further comprising a further plurality of sensing areas, wherein the measurement circuit is coupled to the further plurality of sensing areas and is operable to generate further output signals indicative of couplings between the pointing object and respective ones of the further sensing areas;

and the controller is operable to receive the further output signals from the measurement circuit, to determine a combination of the further sensing areas activated by the presence of the pointing object, to compare the combination of activated further sensing areas with at least one predefined combination of the further sensing areas, and to determine a further selected one of the sensing areas according to a correspondence between the combination of activated further sensing areas and the at least one predefined combinations of further sensing areas.

14. A touch-sensitive user interface according to claim 12, wherein the controller is operable to determine a selected one of the first-mentioned selected one of the first-mentioned sensing areas and the further selected one of the further sensing areas.

15. A touch sensitive user interface according to claim 13, wherein each sensing area has a position within the sensing region and the controller is operable to determine a selected one of the first-mentioned selected one of the sensing areas and the further selected one of the further sensing areas by taking account of the positions of the respective selected sensing areas within the sensing region.

16. A touch sensitive user interface according to claim 13, wherein the controller is operable to determine a selected one of the first-mentioned selected one of the sensing areas and the further selected one of the further sensing areas by taking account of output signals associated with these sensing regions.

17. An apparatus comprising a touch-sensitive user interface according to claim 1.

18. A method for determining which of a plurality of sensing areas in a sensing region is selected by a pointing object, the method comprising:

measuring a coupling between the pointing object and respective ones of the sensing areas;

determining from the measured couplings a combination of sensing areas activated by the presence of the pointing object, comparing the combination of activated sensing areas with at least one predefined combinations of sensing areas; and

determining a selected one of the sensing areas according to a correspondence between the combination of activated sensing areas and a one of the at least one predefined combinations of sensing areas.

19. A method according to claim 18, wherein the measured couplings are capacitive couplings.