Device and method for proximity sensing with force imaging

• US 9,201,468 B2
• Filed: 06/28/2013
• Issued: 12/01/2015
• Est. Priority Date: 06/28/2013
• Status: Active Grant

• Current Assignee: Synaptics Incorporated
• Original Assignee: Synaptics Incorporated
• Inventors: Schediwy, Richard
• Primary Examiner(s): Awad, Amr
• Assistant Examiner(s): Midkiff, Aaron
• Application Number:
  US13/930,749
• Publication Number:
  US 20150002447A1
• Time in Patent Office: 886 Days
• Field of Search: 178 1801- 2004, 345173-178
• US Class Current: 1/1
• CPC Class Codes: G06F 1/1692 the I/O peripheral being a secondary touch screen used as control interface, e.g. virtual buttons or sliders
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• 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

Methods, systems and devices are described for operating an electronic system which includes a first plurality of sensor electrodes disposed in a first layer and configured to detect input objects at an input surface of the input device, the first plurality of sensor electrodes including a first subset of transmitter electrodes; a second plurality of sensor electrodes configured to detect a force imparted to the input surface and configured for capacitive coupling with the first subset of transmitter electrodes; and a compressible dielectric configured to compress in response to force applied to the input surface. The capacitive coupling between the transmitter electrodes and the second plurality of sensor electrodes is configured to vary in response to the applied force.

Claims

1. An input device for an electronic system, comprising:

a pliable component having an input surface and a first plurality of sensor electrodes configured to sense input objects proximate the input surface, wherein the first plurality of sensor electrodes comprises at least a first subset all driven with;

a sensing signal and at least a second subset configured to receive a first type of resulting signal;

a support substrate spaced apart from the pliable component and having a second plurality of sensor electrodes configured to detect a force imparted to the input surface, wherein the second plurality of sensor electrodes comprises at least one electrode configured to receive a second type of resulting signal; and

a spacing layer disposed between the pliable component and the support substrate, the spacing layer including an elastomeric sub-layer and a plurality of rigid dots.

2. The input device of claim 1, wherein the first type of resulting signal comprises effects of input objects proximate the touch surface, and wherein the second type of resulting signal comprises effects of a force applied to the input surface.

3. The input device of claim 1, wherein the plurality of rigid dots extend from a surface of the pliable component.

4. The input device of claim 3, wherein at least the first subset of the first plurality of electrodes is interposed between the rigid dots.

5. The input device of claim 3, wherein at least the first subset of the first plurality of electrodes overlaps at least a portion of the rigid dots.

6. The input device of claim 3, wherein the elastomeric substrate is adjacent to the support substrate and overlays the second plurality of sensor electrodes.

7. The input device of claim 1, wherein the plurality of rigid dots extends from a surface of the support substrate, and at least a first subset of the second plurality of electrodes is interposed between the rigid dots.

8. The input device of claim 7, wherein at least a first subset of the second plurality of electrodes overlaps at least a portion of the rigid dots.

9. The input device of claim 7, wherein the elastomeric substrate is adjacent to the pliable component and overlays at least a portion of the first plurality of sensor electrodes.

10. The input device of claim 1, wherein the spacing layer comprises a gas disposed in a volume surrounding the rigid dots, and further wherein in response to pressure applied to the input surface, the elastomeric substrate is configured to deform into a portion of the volume, locally displacing the gas.

11. The input device of claim 10, wherein in response to applied pressure, the measured capacitance between the at least one electrode configured to transmit a sensing signal and the at least one electrode configured to receive a second type of resulting signal changes substantially at least in part due to an increase in the effective dielectric constant associated with the region between the least one electrode configured to transmit a sensing signal and the at least one electrode configured to receive a second type of resulting signal.

12. The input device of claim 11, wherein the elastomeric substrate is characterized by a dielectric constant in the range of 2 to 7, and the gas is characterized by a dielectric constant of about 1.

13. The input device of claim 1, wherein the height of the rigid dots is in the range of about 50 to 250 microns, and the ratio of the thickness of the elastomeric sub-layer to dot height is in the range of about 1.5:

1 to 3;

1.

14. The input device of claim 1, wherein the pliable component comprises at least one substrate, and wherein the at least one electrode configured to transmit a sensing signal and the at least one electrode configured to receive a second type of resulting signal are arranged on one of:

a single side of the at least one substrate;

opposing sides of the at least one substrate; and

separate substrates.

15. The input device of claim 1, further comprising a processing system communicatively coupled to the first plurality of sensor electrodes and the second plurality of sensor electrodes, the processing system comprising:

a sensor module configured to;

receive the first type of resulting signal from the second subset configured to receive the first type of resulting signal; and

receive a second type of resulting signal from the at least one electrode configured to receive the second type of resulting signal; and

a determination module configured to determine positional information and force information for input objects in a sensing region from the first type of resulting signals and the second type of resulting signals.

16. The input device of claim 15, wherein the first type of resulting signals and the second type of resulting signals correspond to the same driven signal.

17. An input device comprising:

a pliable layer including a first plurality of sensor electrodes configured to detect input objects in a sensing region of the input device, the first plurality of sensor electrodes including a subset of transmitter electrodes;

a support substrate including a second plurality of sensor electrodes configured to detect a force imparted to an input surface and configured for capacitive coupling with the subset of transmitter electrodes;

a spacing layer including an elastomeric dielectric sub-layer and a microstructure sub-layer having a plurality of microstructures surrounded by a gas, the spacing layer disposed between the pliable layer and the support substrate and configured to compress in response to force applied to the input surface; and

a processing system communicatively coupled to the first plurality of sensor electrodes and the second plurality of sensor electrodes and configured to;

drive a sensing signal onto all of the subset of transmitter electrodes; and

receive, using the second plurality of sensing electrodes, a resulting signal, which includes effects of the sensing signal and applied force on the input surface;

wherein the resulting signal represents a change in capacitive coupling between the subset of transmitter electrodes and the second plurality of sensor electrodes.

18. The input device of claim 17, wherein the elastomeric dielectric sub-layer is characterized by a first electrical permittivity and the gas is characterized by a second electrical permittivity less than the first electrical permittivity, and further wherein the change in capacitive coupling between the subset of transmitter electrodes and the second plurality of sensor electrodes is due, at least in part, to a change in an effective electrical permittivity of the spacing layer as a result of the applied force.

19. A processing system for use with an input device of a type including a plurality of transmitter electrodes, a first plurality of sensor electrodes configured to receive a first type of resulting signal to detect input objects at an input surface, a second plurality of sensor electrodes configured to receive a second type of resulting signal to detect a force imparted to the input surface, and a spacing layer including a flat elastomeric sub-layer and a rigid dot sub-layer surrounded by a gas, the spacing layer disposed between a pliable layer and a support substrate and configured to deflect in response to force applied to the input surface, the processing system communicatively coupled to the plurality of transmitter electrodes and the first plurality of sensor electrodes and second plurality of sensor electrodes and configured to:

drive a sensing signal onto the plurality of transmitter electrodes;

receive, using the second plurality of electrodes, a resulting signal; and

measure a change in capacitive coupling between the plurality of transmitter electrodes and the second plurality of sensor electrodes resulting from a change in an effective electrical permittivity of the spacing layer during deflection.