Transparent Strain Sensors in an Electronic Device

• US 20170075465A1
• Filed: 09/11/2015
• Published: 03/16/2017
• Est. Priority Date: 09/11/2015
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Meyer, David J., Pedder, James E., Kang, Sunggu, Zhong, John Z.
• Granted Patent: US 9,874,965 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01L 1/18 using properties of piezo-resistive materials, i.e. materials of which the ohmic resistance varies according to changes in magnitude or direction of force applied to the material
• CPC Class Codes: G01L 1/205 using distributed sensing elements
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

An electronic device includes one or more transparent strain sensors configured to detect strain based on an amount of force applied to the electronic device, a component in the electronic device, and/or an input surface of the electronic device. The one or more transparent strain sensors may be included in or positioned below an input surface that is configured to receive touch inputs from a user. The area below the input surface can be visible to a user when the user is viewing the input surface. The one or more transparent strain sensors are formed with a nanostructure, including a nanomesh or nanowires.

Claims

1. An electronic device, comprising:

an input surface configured to receive touch inputs;

a strain sensitive structure positioned below the input surface, the strain sensitive structure comprising;

a transparent insulating substrate; and

a first transparent strain sensor formed with a nanostructure and positioned on a first surface of the transparent insulating substrate; and

a processing device operably connected to the first transparent strain sensor and configured to determine an amount of force applied to the input surface based on signals received from the first transparent strain sensor.

2. The electronic device of claim 1, further comprising a second transparent strain sensor formed with a nanostructure and positioned on a second surface of the transparent insulating substrate.

3. The electronic device of claim 2, wherein the first and second transparent strain sensors are aligned vertically to produce a strain sensing element.

4. The electronic device of claim 3, wherein the processing device is configured to determine an amount of force applied to the input surface based on signals received from the strain sensing element.

5. The electronic device of claim 4, further comprising sense circuitry operably connected between the strain sensing element and the processing device.

6. The electronic device of claim 1, wherein the first transparent strain sensor is included in a first film layer comprising a first set of transparent strain sensors.

7. The electronic device of claim 1, wherein the nanostructure is formed with nickel.

8. The electronic device of claim 7, wherein the nanostructure comprises a nanomesh.

9. The electronic device of claim 7, wherein the nanostructure comprises a nanowire.

10. The electronic device of claim 1, wherein the input surface comprises a touch sensitive display.

11. An electronic device, comprising:

a display stack for a display, comprising;

a cover glass; and

a strain sensitive structure positioned below the cover glass, the strain sensitive structure comprising;

a first transparent strain sensor positioned on a first surface of a transparent substrate; and

a second transparent strain sensor positioned on a second surface of the transparent substrate, the first and second transparent strain sensors positioned in an area that is visible when viewing the display and the second transparent strain sensor aligning vertically with the first transparent strain sensor to produce a strain sensing element,

wherein each of the first and second transparent strain sensors is formed with a nanostructure.

12. The electronic device of claim 11, wherein the nanostructure comprises a nickel nanostructure.

13. The electronic device of claim 12, wherein the nanostructure comprises a nanomesh.

14. The electronic device of claim 12, wherein the nanostructure comprises a nanowire.

15. The electronic device of claim 11, further comprising sense circuitry operably connected to the strain sensing element.

16. The electronic device of claim 15, further comprising a processing device operably connected to the sense circuitry and configured to determine an amount of force applied to the cover glass based on signals received from the strain sensing element.

17. The electronic device of claim 11, further comprising a display layer positioned between the cover glass and the strain sensitive structure.

18. The electronic device of claim 17, further comprising a back light unit positioned below the strain sensitive structure.

19. A method of producing a transparent strain sensitive structure in an electronic device, the method comprising:

providing a set of transparent strain gauges on at least one surface of a transparent substrate, wherein each transparent strain gauge in the set is formed with a nanostructure; and

positioning the strain sensitive structure below an input surface of the electronic device.

20. The method of claim 19, wherein the nanostructure comprises a nickel nanostructure.

21. The method of claim 19, wherein the input surface comprises a cover glass disposed over a display layer, wherein the transparent strain sensitive structure is positioned below the display layer.