Input device with force sensing and haptic response

• US 9,557,857 B2
• Filed: 04/26/2011
• Issued: 01/31/2017
• Est. Priority Date: 04/26/2011
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Schediwy, Richard R.
• Primary Examiner(s): Boddie, William
• Assistant Examiner(s): Earles, Bryan
• Application Number:
  US13/094,658
• Publication Number:
  US 20120274599A1
• Time in Patent Office: 2,107 Days
• Field of Search: 345/173, 345/174, 345/156
• US Class Current: 1/1
• 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 plurality of sensor electrodes disposed on the first substrate that capacitively detect objects in a sensing region;

a piezoelectric assembly (PA) comprising;

a piezoelectric material;

a second electrode physically coupled to a first side of the 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; and

a transmission element physically coupled to the third electrode;

a spacing element coupled to the first substrate and defining an opening between the first electrode and the second electrode,

wherein the spacing element is static, and

wherein the PA is configured to;

deflect into the opening and change the variable capacitance in response to a force applied by a user that biases the transmission element relative to the first substrate, wherein the force is measured based on the change in the variable capacitance; and

deform to generate a haptic response for the user; and

a base substrate located below the transmission element, the first electrode, the second electrode, and the third electrode,

wherein the base substrate pushes, in response to the force applied by the user, the transmission element in the opposite direction of the force applied by the user causing the PA to deflect in the opposite direction of the force applied by the user.

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 deform 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 deforming 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 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 element.

9. 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.

10. A method comprising:

providing a first electrode disposed on a first substrate;

providing a plurality of sensor electrodes disposed on the first substrate that capacitively detect objects in a sensing region;

providing a piezoelectric assembly (PA) comprising;

a piezoelectric material;

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

a transmission element coupled to the third electrode;

providing a spacing element coupled to the first substrate and defining an opening between the first electrode and the second electrode,

wherein the spacing element is static, and

wherein the PA is configured to;

deflect into the opening and change the variable capacitance in response to a force applied by a user that biases the transmission element relative to the first electrode, wherein the force is measured based on the change in the variable capacitance; and

deform to generate a haptic response for the user; and

providing a base substrate located below the transmission element, the first electrode, the second electrode, and the third electrode,

wherein the base substrate pushes, in response to the force applied by the user, the transmission element in the opposite direction of the force applied by the user causing the PA to deflect in the opposite direction of the force applied by the user.

11. The method of claim 10 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.

12. The method of claim 11 further comprising holding the second electrode at a constant voltage while the determining the force information.