Touchpad with Capacitive Force Sensing

• US 20120327025A1
• Filed: 09/06/2012
• Published: 12/27/2012
• Est. Priority Date: 05/24/2010
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Huska, Andrew P., Krumpelman, Douglas M., Peterson, Cody G.
• Granted Patent: US 9,349,552 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: H01H 13/85 characterised by tactile feedback features
• CPC Class Codes: H01H 2003/008 with a haptic or a tactile feedback controlled by electrical means, e.g. a motor or magnetofriction
• CPC Class Codes: H01H 2215/05 electromechanical

Abstract

Described herein are techniques related to a touchpad with capacitive force sensing. The described techniques may determine the point or region of a user-engagement surface contacted by a user. In addition, the described techniques may also determine a force of the user'"'"'s finger press on the user-engagement surface using one or more capacitance force-sensors. Furthermore, the described techniques may offer active tactile feedback (i.e., haptics) to the user'"'"'s finger touching the user-engagement surface. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

1. An input device comprising:

a touchsurface;

a sensor board coupled to the touchsurface, the sensor board including a capacitive touch sensor configured to detect positions of one or more input objects proximate to the touchsurface and one or more capacitive-sensing strips;

a spring plate including an interior space configured to be coupled to the sensor board and a return mechanism configured to be coupled to a housing,

wherein the spring plate forms, at least in part, a first capacitive force sensor with the one or more capacitive-sensing strips such that a force imparted on the touchsurface deflects the interior space relative to the return mechanism and changes a capacitance of the first capacitive force sensor.

2. An input device as recited in claim 1, wherein the spring plate is a conductive plane of sheet metal.

3. An input device as recited in claim 1, the return mechanism comprises a plurality of leaf springs.

4. An input device as recited in claim 1, wherein the spring plate is configured to allow deflection of the interior space relative the housing in response to a force imparted on the touchsurface.

5. An input device as recited in claim 1, wherein the first capacitive force sensors is formed between the one or more capacitive-sensing strips and one or more capacitive-sensing strips leaf springs.

6. An input device as recited in claim 1, wherein the sensor board comprises two or more capacitive-sensing strips and wherein the first capacitive force sensor is formed between the two or more capacitive-sensing strips and the spring plate.

7. An input device as recited in claim 6, wherein the return mechanism comprises a plurality of leaf springs and the sensor board comprises a plurality of capacitive-sensing strips such that the spring plate forms a plurality of force sensing capacitors, each force sensing capacitor comprising a pair of capacitive-sensing strips and a leaf spring.

8. An input device as recited in claim 1, wherein the sensor board comprises a printed circuit board and the capacitive touch sensor comprises a capacitive-sensing pattern disposed on the sensor board.

9. An input device as recited in claim 1, further comprising a sensor module, wherein the sensor module is configured to determine a position of the one or more input objects proximate to the touchsurface and a force imparted on the touchsurface by the one or more input objects.

10. An input device as recited in claim 9, wherein the sensor module is configured to determine the position of the one or more input objects using the capacitive touch sensor and is further configured to determine the force imparted on the touchsurface by the one or more input objects using one or more input objects one capacitive force sensors.

11. An input device as recited in claim 1, wherein the one or more input objects are selected from a group consisting of a human finger, a human body part, a pen, a pencil, and a stylus.

12. A method facilitating an operation of a touchpad, the touchpad comprising a touchsurface coupled to a sensor board, wherein the sensor board includes a capacitive touch sensor configured to detect positions of one or more input objects proximate to the touchsurface and one or more capacitive-sensing strips;

a conductive substrate including a return mechanism and an interior portion, wherein the interior portion is coupled to the sensor board and the return mechanism is coupled to a housing, wherein the conductive substrate forms a first capacitive sensor; and

a first capacitive force sensor including the one or more capacitive-sensing strips and the conductive substrate, the method comprising;

determining, based upon one or more signals from the capacitive touch sensor, positional information of one or more input objects proximate to the touchsurface;

determining, based upon one or more signals the first capacitive force sensor, a force imparted by the one or more input objects onto the touchsurface; and

performing a user-interface feedback action based on one or more of the positional information or the force imparted on the touchsurface.

13. A method as recited in claim 12, wherein the determining of the force includes determining a variable capacitance of the first capacitive force sensor from a deflection of the one or more capacitive-sensing strips relative to the conductive substrate.

14. A method as recited in claim 12, wherein the determining of the force includes determining a variable capacitance of the first capacitive force sensor from a deflection of the one or more capacitive-sensing strips relative to the conductive substrate, the first capacitive force sensor include the one or more capacitive-sensing strips and the return mechanism of the conductive substrate.

15. A method as recited in claim 12, wherein the conductive substrate is configured to respond to a force imparted on the touchsurface by enabling deflection of the interior space relative the housing.

16. A method as recited in claim 12, wherein the sensor board includes two or more capacitive-sensing strips and wherein the first capacitive force sensor is formed between the two or more capacitive-sensing strips and the return mechanism of the conductive substrate.

17. A method as recited in claim 12, wherein:

the return mechanism includes a plurality of leaf springs and the sensor board includes a plurality of capacitive-sensing strips such that the spring plate forms a plurality of capacitive force sensors, each capacitive force sensor including a pair of capacitive-sensing strips and a leaf spring; and

the determining of the force is based upon one or more signals from the plurality of capacitive force sensors.

18. A method as recited in claim 12, wherein the user-interface feedback action is selected from a group consisting of accessing a file, menu pull down, menu selection, icon or button selection, program execution, properties access, cursor positioning, character or image selection, single-click type function, double-click type function, and right-click type function, viewing and/or selecting balloons, viewing and/or selecting check boxes, selecting a command button, selecting a command link, dropping down drop-down lists and/or combo boxes, opening a link, viewing and/or selecting list boxes, viewing and/or selecting list views, viewing and/or selecting notifications, viewing and/or selecting progress bars, viewing and/or selecting progressive disclosure controls, viewing and/or selecting radio buttons, viewing and/or selecting search boxes, viewing and/or selecting sliders, viewing and/or selecting spin control, viewing and/or selecting status bars, viewing and/or selecting tabs, viewing and/or selecting text boxes, viewing and/or selecting tooltips, viewing and/or selecting infotips, viewing and/or selecting tree views, viewing and/or selecting windows, viewing and/or selecting menus, viewing and/or selecting toolbars, viewing and/or selecting ribbons, dragging and/or dropping functions, copying functions, cutting function, pasting function, and cut-and-pasting function.

19. A processing system of a touchpad, the touchpad comprising:

a position-sensing capacitive sensor disposed on a sensor board;

a capacitive-sensing strip disposed on the sensor board,

wherein the capacitive-sensing strip forms a force-sensing capacitive sensor with a conductive substrate coupled to the sensor board, such that a force imported on a touchsurface of the touchpad deflects the capacitive-sensing strip relative to a spring of the conductive substrate;

the processing system comprising a sensor module configured to;

determine a position of one or more input objects on the touchsurface of the touchpad from one or more of the force-sensing capacitive sensor or the position-sensing capacitive sensor;

determine a force imparted on the touchsurface of the touchpad by the one or more input objects from one or more of the force-sensing capacitive sensor or the position-sensing capacitive sensor.

20. A processing system as recited in claim 19, further comprising a communications module configured to report the determined positions and forces to a host.

21. A processing system as recited in claim 19, wherein the determining of the force includes determining a variable capacitance of the force-sensing capacitive sensor from a deflection of the one or more capacitive-sensing strips relative to the spring of the conductive substrate

22. A processing system as recited in claim 19, wherein an interior space of the conductive substrate is coupled to the sensor board and the spring is coupled to a housing, such that deflection of the interior space relative the housing occurs in response to a force imparted on the touchsurface.

23. A processing system as recited in claim 19, wherein the sensor board includes two or more capacitive-sensing strips and wherein the capacitive force sensor is formed between the two or more capacitive-sensing strips and the spring of the conductive substrate.

24. A processing system as recited in claim 19, wherein:

the conductive substrate includes a plurality of leaf springs and the sensor board includes a plurality of capacitive-sensing strips such that the conductive substrate forms a plurality of force-sensing capacitive sensor, each force-sensing capacitive sensor comprising a pair of capacitive-sensing strips and a leaf spring;

the processing system is configured to determine a force imparted on the touchsurface from the plurality of capacitive force sensors.