FORCE SENSING SWITCH

• US 20160358737A1
• Filed: 08/22/2014
• Published: 12/08/2016
• Est. Priority Date: 08/23/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Brooks, Ryan P., Brock, John M., Hoen, Storrs T.
• Granted Patent: US 10,032,592 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01H 13/14 Operating parts, e.g. push-button
• CPC Class Codes: H01H 13/52 the contact returning to its original state immediately upon removal of operating force, e.g. bell-push switch
• CPC Class Codes: H01H 13/64 wherein the switch has more than two electrically distinguishable positions, e.g. multi-position push-button switches
• CPC Class Codes: H01H 2239/052 Strain gauge
• CPC Class Codes: H01H 89/00 Combinations of two or more different basic types of electric switches, relays, selectors and emergency protective devices, not covered by any single one of the other main groups of this subclass
• CPC Class Codes: H03K 17/9625 using a force resistance transducer

Abstract

A force sensing switch for use in an electronic device can include one or more dome switches disposed over a top surface of a deflectable beam. One or more strain gauges can be disposed over at least one surface of the deflectable beam. An electronic device that includes at least one force sensing switch can further include a processing device operatively connected to the one or more strain gauges. Alternatively or additionally, an electrode can be disposed under a bottom surface of the deflectable beam and a capacitance measured between the bottom surface and the electrode.

Claims

1. A force sensing switch for an electronic device, comprising:

a deflectable beam;

a dome switch disposed over a top surface of the deflectable beam; and

a strain gauge disposed over a surface of the deflectable beam.

2. The force sensing switch as in claim 1, wherein the deflectable beam includes support structures that extend out from the deflectable beam and connect to a support surface.

3. The force sensing switch as in claim 1, further comprising at least one additional strain gauge disposed over a surface of the deflectable beam.

4. The force sensing switch as in claim 3, wherein at least one additional strain gauge is disposed over the top surface of the deflectable beam.

5. The force sensing switch as in claim 1, wherein the strain gauge is disposed over the top surface of the deflectable beam.

6. An electronic device, comprising:

a force sensing switch, comprising;

a deflectable beam;

a dome switch disposed over a top surface of the deflectable beam; and

a strain gauge disposed over a surface of the deflectable beam; and

a processing device operatively connected to the strain gauge and adapted to determine an amount of applied force based on a strain measurement received from the strain gauge.

7. The electronic device as in claim 6, wherein the strain gauge is disposed over the top surface of the deflectable beam.

8. The electronic device as in claim 6, further comprising at least one additional strain gauge disposed over a surface of the beam, wherein each additional strain gauge is operatively connected to the processing device.

9. The electronic device as in claim 6, wherein the electronic device comprises one of a remote control device, a mouse, a smart telephone, and a computer.

10. A method for operating a force sensing switch that includes a strain gauge and a dome switch disposed over a surface of a deflectable beam, wherein the force sensing switch is disposed below an input surface in an electronic device, the method comprising:

receiving a strain measurement from the strain gauge that represents an amount of strain of the deflectable beam when a deformable structure of the dome switch deforms based on a force applied to the input surface; and

determining an amount of force applied to the input surface based on the strain measurement.

11. The method as in claim 10, wherein the deformation of the deformable structure of the dome switch actuates the dome switch.

12. The method as in claim 10, further comprising receiving on the input surface the force applied by the user.

13. The method as in claim 10, further comprising not recognizing the actuation of the dome switch such that an action is not taken based on the actuation of the dome switch.

14. A method for determining an operating mode of a force sensing switch that includes a strain gauge disposed over a surface of a deflectable beam and a dome switch disposed over a top surface of the deflectable beam, wherein the force sensing switch is disposed below an input surface in an electronic device, the method comprising:

determining whether the force sensing switch is to operate as a dome switch or as a force sensing switch;

if the force sensing switch is to operate as a dome switch, determining whether the dome switch is actuated; and

if the force sensing switch is to operate as a force sensing switch, determining an amount of force applied to the input surface based on a strain measurement received from the strain gauge.

15. The method as in claim 14, further comprising transmitting an on signal to a processing device when the dome switch is actuated.

16. The method as in claim 14, further comprising transmitting the determined amount of force to a processing device when the force sensing switch operates as a force sensing switch.

17. An electronic device, comprising:

a deflectable beam;

a dome switch disposed over a top surface of the deflectable beam; and

an electrode disposed under a bottom surface of the deflectable beam, wherein the bottom surface of the deflectable beam and the electrode form a capacitive sensing element.

18. The electronic device as in claim 17, further comprising a sense line connected between a sense circuit and the electrode.

19. The electronic device as in claim 18, further comprising a processing device connected to the sense circuit.

20. A method for operating a force sensing switch that includes a dome switch disposed over a top surface of a deflectable beam and an electrode disposed under a bottom surface of the deflectable beam, wherein the force sensing switch is disposed below an input surface in an electronic device, the method comprising:

measuring a capacitance between the bottom surface of the deflectable beam and the electrode when a deformable structure of the dome switch deforms based on a force applied to the input surface; and

determining an amount of force applied to the input surface based on the measured capacitance.