DETECTION OF INTENDED KEY ACTIVATION ON A MOBILE DEVICE

• US 20110115652A1
• Filed: 11/13/2009
• Published: 05/19/2011
• Est. Priority Date: 11/13/2009
• Status: Active Grant

• Current Assignee: Malikie Innovations Limited (Key Patent Innovations Limited)
• Original Assignee: Blackberry Limited
• Inventors: WU, Ken, Werner, Colin Mark, CHEN, Chao, KUHL, Lawrence Edward, MARUI, Keizo
• Granted Patent: US 8,294,601 B2
• Time in Patent Office: Days
• US Class Current: 341/24
• CPC Class Codes: G06F 1/3231 Monitoring the presence, absence or movement of users
• CPC Class Codes: G06F 3/0202 Constructional details or processes of manufacture of the input device
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method and device are provided for preventing unintended activation of one or more hard keys on a mobile device. A capacitive sensor senses a capacitance level at a location on the keyboard, to detect whether a hard key is being actuated by a human hand or human skin. If the sensed capacitance level exceeds a key activation capacitance threshold, a key circuit connection is identified as being associated with an intended hard key activation. If the measured capacitance level is within an uncertainty tolerance below the key activation capacitance threshold, a secondary capacitance level is measured at a non-keyboard location. The key circuit connection is identified as being associated with an intended hard key activation when the measured secondary capacitance level exceeds a key activation confirmation threshold. Additional secondary indicators can be obtained based on size and shape capacitance pattern, timing information, and an active application or device state.

Claims

1. A mobile device, comprising:

a keyboard including a keypad defining a plurality of hard keys;

a printed circuit board (PCB) including a plurality of key circuits to detect actuation of the plurality of hard keys;

a capacitive sensor provided between the keypad and the printed circuit board and arranged to detect a capacitance level on the keypad; and

a processor arranged to identify an intended hard key activation in response to receiving an indication of connection of one of the plurality of key circuits, and when a detected capacitance level on the keypad exceeds a key activation capacitance threshold.

2. The mobile device of claim 1 further comprising a light shielding capacitive sensing film providing back light shielding and capacitance detection, the capacitive sensor being provided on a surface of the light shielding capacitive sensing film.

3. The mobile device of claim 2 wherein the capacitive sensor provided on the light shielding capacitive sensing film is implemented by way of a conductive coating.

4. The mobile device of claim 3 wherein the conductive coating comprises an x-channel coating provided on one side of the light shielding capacitive sensing film, and a y-channel coating provided on another side of the light shielding capacitive sensing film.

5. The mobile device of claim 4 wherein the x-channel coating is provided on a keyboard-facing side of the light shielding capacitive sensing film, and the y-channel coating is provided on a PCB-facing side of the light shielding capacitive sensing film.

6. The mobile device of claim 1 further comprising:

a housing; and

a secondary capacitive sensor disposed at a non-keyboard location on the mobile device and arranged to detect a secondary capacitance level at the non-keyboard location,

wherein the processor is arranged to compare the measured secondary capacitance level at the non-keyboard location to a key activation confirmation threshold, and to identify the key circuit connection as being associated with an intended hard key activation when the measured secondary capacitance level exceeds the key activation confirmation threshold.

7. The mobile device of claim 1 wherein the key activation capacitance threshold is about 2 pico Farads greater than a base capacitance, the base capacitance being measured in the absence of actuation of one of the plurality of hard keys by human skin.

8. A method of identifying an intended hard key actuation on a mobile device, the mobile device having a keyboard including a keypad defining a plurality of hard keys, and a printed circuit board including a plurality of key circuits to detect actuation of the plurality of hard keys, the method comprising:

receiving an indication of connection of a selected one of the plurality of key circuits associated with a selected one of the plurality of hard keys;

obtaining a measured capacitance level at a keyboard location near the selected hard key;

comparing the measured capacitance level at the keyboard location to a key activation capacitance threshold; and

identifying the key circuit connection as being associated with an intended hard key activation when the measured capacitance level exceeds the key activation capacitance threshold.

9. The method of claim 8 further comprising, intercepting the key circuit connection before an associated input is passed to an active application.

10. The method of claim 8 further comprising, processing an input associated with the actuation of the selected hard key.

11. The method of claim 8 further comprising, if the measured capacitance level is within an uncertainty tolerance below the key activation capacitance threshold:

obtaining a measured secondary capacitance level at a non-keyboard location of the mobile device;

comparing the measured secondary capacitance level at the non-keyboard location to a key activation confirmation threshold; and

identifying the key circuit connection as being associated with an intended hard key activation when the measured secondary capacitance level exceeds the key activation confirmation threshold.

12. A computer-readable medium storing statements and instructions for execution by a processor to perform a method of identifying an intended hard key actuation on a mobile device, the mobile device having a keyboard including a keypad defining a plurality of hard keys, and a printed circuit board including a plurality of key circuits to detect actuation of the plurality of hard keys, the method comprising:

receiving an indication of connection of a selected one of the plurality of key circuits associated with a selected one of the plurality of hard keys;

obtaining a measured capacitance level at a keyboard location near the selected hard key;

comparing the measured capacitance level at the keyboard location to a key activation capacitance threshold; and

identifying the key circuit connection as being associated with an intended hard key activation when the measured capacitance level exceeds the key activation capacitance threshold.

13. The computer-readable medium of claim 12 wherein the method further comprises, intercepting the key circuit connection before an associated input is passed to an active application.

14. The computer-readable medium of claim 12 wherein the method further comprises, processing an input associated with the actuation of the selected hard key.

15. The computer-readable medium of claim 12 wherein the method further comprises, if the measured capacitance level is within an uncertainty tolerance below the key activation capacitance threshold:

obtaining a measured secondary capacitance level at a non-keyboard location of the mobile device;

comparing the measured secondary capacitance level at the non-keyboard location to a key activation confirmation threshold; and

identifying the key circuit connection as being associated with an intended hard key activation when the measured secondary capacitance level exceeds the key activation confirmation threshold.