Magnetic Re-Centering Mechanism for a Capacitive Input Device

• US 20090135136A1
• Filed: 11/23/2007
• Published: 05/28/2009
• Est. Priority Date: 11/23/2007
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Orsley, Timothy James
• Granted Patent: US 7,978,175 B2
• Time in Patent Office: Days
• US Class Current: 345/157
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/0354 with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
• CPC Class Codes: G06F 3/03548 Sliders, in which the moving part moves in a plane
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

Various embodiments provide an enhanced mobile computing experience by providing an input device in a mobile electronic device that is configured to accurately and quickly re-center a button or other user interface while providing a sensation of enhanced tactile feedback to a user. The biasing force of a magnetic re-centering mechanism is employed to overcome frictional forces acting on the button during its travel forwards and backwards and tilting to insure that the button is returned quickly and accurately to a resting position. The magnetic re-centering mechanism has a low profile, and permits the input device and the mobile electronic device within which the input device is disposed to have small form factors.

Claims

1. An input device, comprising:

a moveable upper magnet having an upper surface and a lower surface;

an electrically conductive member disposed below the lower surface of the upper magnet and moveable in conjunction therewith;

an electrode array comprising a plurality of electrically conductive sense electrodes and at least one drive electrode the sense and drive electrodes being spaced apart from the electrically conductive member by a gap;

a stationary lower magnet disposed below the plurality of sense electrodes and the drive electrode, the lower magnet being configured and positioned to attract the upper magnet to a centered rest position thereabove;

a drive signal circuit configured to provide an electrical drive signal to the electrically conductive member through the drive electrode and the gap, and

a capacitance measurement circuit operably coupled to the electrically conductive member and the sense electrodes, the circuit being configured to detect changes in capacitance occurring between the electrically conductive member and the sense electrodes when the upper magnet is moved from the centered rest position;

wherein the upper magnet is moveable by a user in respect of the lower magnet, the plurality of sense electrodes and the drive electrode disposed therebelow, and the lower magnet is further configured to exert a magnetic force on the upper magnet to return the upper magnet to the centered rest position when the upper magnet is moved from the centered rest position and then released by the user.

2. The input device of claim 1, wherein the upper magnet and the electrically conductive member are configured to slide along a principal axis.

3. The input device of claim 1, wherein the upper magnet and the electrically conductive member are further configured to tilt to at least one side of the principal axis.

4. The input device of claim 1, wherein each of the plurality of sense electrodes comprises a plurality of discrete electrode surfaces physically separated from one another in the electrode array, and where the discrete electrode surfaces are electrically connected to one another.

5. The input device of claim 1, wherein the electrically conductive member and the electrode array are configured such that substantially equal portions of surface area of the drive electrode remain disposed beneath the electrically conductive member as the upper magnet is moved over the electrode array.

6. The input device of claim 1, wherein the device is further configured to effect 5-way functionality.

7. The input device of claim 1, wherein the device is further configured to effect at least one of scrolling and clicking functionality.

8. The input device of claim 1, further comprising a button operably connected to the upper magnet.

9. The input device of claim 1, further comprising a button operably connected to the upper magnet, wherein the device is further configured to effect at least one of clicking and scrolling functionality when the button is depressed downwardly by a user.

10. The input device of claim 1, wherein the device is further configured to tilt to either side of the principal axis, and such tilting is employed to effect at least one operational function in the device.

11. The input device of claim 1, wherein a button is disposed over the upper magnet, the upper magnet has a hole disposed therethrough, and a plunger is disposed in the hole and operably connected to the button.

12. The input device of claim 11, wherein a depressable dome is disposed over the upper magnet.

13. The input device of claim 1, wherein the electrically conductive member has a deformable area formed or disposed therein or thereon at locations corresponding approximately to a bottom portion of the plunger configured to engage at least portions of the deformable area.

14. The input device of claim 1, further comprising a flexible membrane configured to impart at least one of leak-tightness, leak resistance, gas-tightness, gas resistance, vapor-tightness and vapor resistance to the device.

15. The input device of claim 1, wherein the capacitance measurement circuit is operably connected to a host processor.

16. The input device of claim 1, wherein the device is incorporated into and forms a portion of a mobile electronic device or a mouse.

17. The input device of claim 1, wherein the mobile electronic device is at least one of a laptop computer, a personal data assistant (PDA), a mobile telephone, a cellular telephone, a radio, an MP3 player, a transceiver, and a portable music player.

18. The input device of claim 1, wherein at least one of the drive signal circuit and the capacitance measurement circuit is incorporated into an integrated circuit.

19. The input device of claim 1, wherein the electrode array is disposed atop a substrate.

20. The input device of claim 19, wherein the substrate is at least one of a printed circuit board and a flexible printed circuit board.

21. The input device of claim 1, further comprising at least one mechanical biasing mechanism configured to exert a resisting force on the upper magnet, or a button, fascia or other intermediary member operably connected thereto, in response to a user moving the upper magnet, the button, the fascia or the intermediary member into contact therewith.

22. A method of using or making an input device, comprising:

providing a moveable upper magnet having an upper surface and a lower surface;

providing an electrically conductive member disposed below the lower surface of the upper magnet and moveable in conjunction therewith;

providing an electrode array comprising a plurality of electrically conductive sense electrodes and at least one drive electrode, the sense and drive electrodes being spaced apart from the electrically conductive member by a gap;

providing a stationary lower magnet disposed below the plurality of sense electrodes and the drive electrode, the lower magnet being configured and positioned to attract the upper magnet to a centered rest position thereabove;

providing a drive signal circuit configured to provide an electrical drive signal to the electrically conductive member through the drive electrode and the gap, and

providing a capacitance measurement circuit operably coupled to the electrically conductive member and the sense electrodes, the circuit being configured to detect changes in capacitance occurring between the electrically conductive member and the sense electrodes when the upper magnet is moved from the centered rest position;

configuring the upper magnet, the electrically conductive member, the electrode array and the lower magnet such that the upper magnet is moveable by a user in respect of the lower magnet and the plurality of sense electrodes and the drive electrode disposed therebelow, and the lower magnet exerts a magnetic force on the upper magnet to return the upper magnet to the centered rest position when the upper magnet is moved from the centered rest position and then released by the user.

23. The method of claim 22, further comprising configuring the upper magnet and the electrically conductive member to slide along a principal axis.

24. The method of claim 23, further comprising configuring the upper magnet and the electrically conductive member to slide along the principal axis and tilt to at least one side of the principal axis.

25. The method of claim 22, wherein each of the plurality of sense electrodes comprises a plurality of discrete electrode surfaces physically separated from one another in the electrode array, and where the discrete electrode surfaces are electrically connected to one another.