INPUT DEVICE WITH FORCE SENSING AND HAPTIC RESPONSE

• US 20120274599A1
• Filed: 04/26/2011
• Published: 11/01/2012
• Est. Priority Date: 04/26/2011
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Schediwy, Richard R.
• Granted Patent: US 9,557,857 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

Devices and methods are provided that facilitate improved input device performance. The devices and methods utilize a first electrode disposed on a first substrate, a second electrode coupled to a first side of a piezoelectric material and a third electrode coupled to a second side of the piezoelectric material. The second electrode and the third electrode are configured to facilitate actuation of the piezoelectric material, while the first electrode and the second electrode define at least part of a variable capacitance that facilitates force determination. A spacing element is coupled to the first substrate and defines a spacing between the first electrode and the second electrode. A transmission element is coupled to the third electrode and configured such that a force biasing the transmission element causes the second electrode to deflect relative to the first electrode, thus changing the variable capacitance.

Claims

1. An input device comprising:

a first electrode disposed on a first substrate;

a second electrode physically coupled to a first side of a piezoelectric material, the second electrode overlapping the first electrode, wherein the first electrode and the second electrode define at least part of a variable capacitance;

a third electrode physically coupled to a second side of the piezoelectric material;

a spacing element coupled to the first substrate and defining a spacing between the first electrode and the second electrode; and

a transmission element physically coupled to the third electrode and configured such that force biasing the transmission element relative to the first substrate causes the second electrode to deflect relative to the first electrode and changes the variable capacitance.

2. The input device of claim 1 further comprising a processing system communicatively coupled to the second electrode and the third electrode, the processing system configured to actuate the piezoelectric material by selectively applying one or more differential voltages across the second and third electrodes.

3. The input device of claim 2 wherein the processing system is configured to generate physical motion in the input device by selectively actuating the piezoelectric material.

4. The input device of claim 1 further comprising a processing system communicatively coupled to the first electrode and the second electrode, the processing system configured to determine force information based on a capacitance value of the variable capacitance.

5. The input device of claim 4 wherein the processing system is configured to hold the second electrode at a constant voltage to determine the force information.

6. The input device of claim 1 further comprising:

a fourth electrode disposed proximate to the first electrode on the first substrate, wherein the fourth electrode further defines the at least part of the variable capacitance; and

a processing system communicatively coupled to the first electrode and the fourth electrode, the processing system configured to determine force information based on a capacitance value of the variable capacitance.

7. The input device of claim 1 further comprising a vent, the vent facilitating gas flow when the second electrode is deflected relative to the first electrode.

8. The input device of claim 1 further comprising a first plurality of sensor electrodes disposed on at least one of the first substrate and the spacing element, the first plurality of capacitive sensor electrodes configured to capacitively detect objects in a sensing region.

9. The input device of claim 1 wherein the transmission element is configured to overlap at least a portion of the second electrode and wherein the transmission element is further dimensioned to at least partially overlap the spacing.

10. The input device of claim 1 wherein the spacing element is coupled to at least one of the second electrode, the third electrode and the piezoelectric material.

11. An input device comprising:

a touch surface configured to be touched by objects in a sensing region;

a first substrate;

a piezoelectric material;

a spacing element coupled to the first substrate and the piezoelectric material, the spacing element defining a first opening;

a plurality of capacitive sensor electrodes, the plurality of capacitive sensor electrodes configured to detect objects in the sensing region;

a first response electrode disposed on the first substrate, the first response electrode at least partially overlapping the first opening in the spacing element;

a second response electrode disposed on a first side of the piezoelectric material, the second response electrode at least partially overlapping the first opening in the spacing element, the first and second response electrodes defining at least part of a first variable capacitance;

a third response electrode disposed on a second side of the piezoelectric material; and

a transmission element physically coupled to the third response electrode and configured such that force applied to the touch surface deflects the second response electrode relative to the first response electrode, changing the first variable capacitance.

12. The input device of claim 11 wherein the plurality of capacitive sensor electrodes are disposed on at least one of the first substrate and the spacing element.

13. The input device of claim 11 further comprising a display underlying the touch surface.

14. The input device of claim 11 further comprising a processing system coupled to the plurality of capacitive sensor electrodes, the first response electrode, the second response electrode, and third response electrode, the processing system configured to:

determine positional information for objects in the sensing region;

determine a first capacitance value of the first variable capacitance;

determine force information for the force applied to the touch surface using the first capacitance value;

generate a haptic response by providing a differential voltage across the second response electrode and third response electrode.

15. The input device of claim 11 further comprising a vent in at least one of the first substrate, piezoelectric material, and spacing element, the vent facilitating gas flow when the second response electrode is deflected relative to the first response electrode.

16. The input device of claim 11 wherein the spacing element is coupled to at least one of the second electrode, the third electrode and the piezoelectric material.

17. A method comprising:

providing a first electrode disposed on a first substrate;

providing a second electrode physically coupled to a first side of a piezoelectric material, the second electrode overlapping the first electrode, wherein the first electrode and the second electrode define at least part of a variable capacitance;

coupling a third electrode to a second side of the piezoelectric material;

providing a spacing element between the first substrate and the piezoelectric material, the spacing element defining a space between the first electrode and the second electrode; and

coupling a transmission element to the piezoelectric material, the transmission element configured such that force biasing the transmission element causes the second electrode to deflect relative to the first electrode and changes the variable capacitance.

18. The method of claim 17 further comprising:

selectively actuating the piezoelectric material by applying one or more differential voltages across the second and third electrodes; and

determining force information based on the variable capacitance.

19. The method of claim 18 wherein the determining force information based on the variable capacitance further comprises holding the second electrode at a constant voltage while the determining the force information.

20. The method of claim 17 further comprising providing a plurality of capacitive sensor electrodes disposed on at least one of the first substrate and the spacing element configured to sense objects in a sensing region.

21. The method of claim 20 further comprising determining positional information for objects in the sensing region.