Apparatus and associated methods

• US 9,887,346 B2
• Filed: 10/05/2012
• Issued: 02/06/2018
• Est. Priority Date: 10/05/2012
• Status: Active Grant

• Current Assignee: Nokia Technologies Oy (Nokia Corporation)
• Original Assignee: Nokia Technologies Oy (Nokia Corporation)
• Inventors: White, Richard, Colli, Alan
• Primary Examiner(s): Dougherty, Thomas
• Application Number:
  US14/432,479
• Publication Number:
  US 20150287904A1
• Time in Patent Office: 1,950 Days
• Field of Search: 310319, 310339
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02N 2/18 producing electrical output from mechanical input, e.g. generators for measurement devices G01
• CPC Class Codes: H02N 2/181 Circuits; Control arrangements or methods
• CPC Class Codes: H10N 30/30 with mechanical input and electrical output, e.g. functioning as generators or sensors
• CPC Class Codes: H10N 30/802 Drive or control circuitry or methods for piezoelectric or electrostrictive devices not otherwise provided for
• CPC Class Codes: H10N 30/878 the principal material being non-metallic, e.g. oxide or carbon based

Abstract

An apparatus comprising: —a piezoelectric convertor layer; and —a proximal first piezoresistive layer being in electrical communication with, a first face of the piezoelectric convertor layer, the apparatus being configured such that when the piezoelectric convertor layer is deformed to generate charge, the proximal piezoresistive layer is configured to control the flow of charge from the piezoelectric convertor layer.

Claims

1. An apparatus comprising:

a piezoelectric convertor layer; and

a proximal first piezoresistive layer being in electrical communication with, a first face of the piezoelectric convertor layer,

the apparatus being configured such that when the piezoelectric convertor layer is deformed to generate charge, the proximal piezoresistive layer is configured to control the flow of charge from the piezoelectric convertor layer.

2. An apparatus according to claim 1, wherein the proximity of the piezoelectric convertor layer and the piezoresistive layer is such that the electric field generated by the deformation of the piezoelectric convertor layer causes a change in the resistance of the piezoresistive layer compared to the non-deformed state to thereby control the flow of charge from the piezoelectric convertor layer.

3. An apparatus according to claim 1, wherein the proximity of the piezoelectric convertor layer and the piezoresistive layer is such that they are in physical contact so that the deformation of the piezoelectric convertor layer causes a deformation in the piezoresistive layer to change the resistance of the piezoresistive layer compared to the non-deformed state to thereby control the flow of charge from the piezoelectric convertor layer.

4. The apparatus of claim 1, wherein the apparatus is configured such that the resistance of the first piezoresistive layer decreases in response to compression applied to the piezoelectric convertor layer.

5. The apparatus of claim 1, wherein the first piezoresistive layer comprises a quantum tunneling composite.

6. The apparatus of claim 1, wherein the first piezoresistive layer comprises doped graphene in direct contact with the piezoelectric convertor layer, the resistance of the doped graphene being configured to change in response to an electric field being generated by the piezoelectric convertor layer in response to deformation.

7. The apparatus of claim 1, wherein the piezoelectric convertor layer and the first piezoresistive layer are configured to be transparent.

8. The apparatus of claim 1, wherein the piezoelectric convertor layer comprises:

a piezoelectric layer;

a first conducting layer in direct electrical communication with the first face of a piezoelectric layer; and

a second conducting layer in direct electrical communication with the opposing second face of the piezoelectric layer.

9. The apparatus of claim 1, wherein the apparatus comprises:

a first circuit portion electrically connected to;

the first face of the piezoelectric convertor layer via the first piezoresistive layer; and

the opposing second face of the piezoelectric convertor,

the first circuit portion being configured to store charge generated by the piezoelectric convertor layer; and

a second circuit portion connected to;

the first face of the piezoelectric convertor layer; and

the opposing second face of the piezoelectric convertor layer,

the second circuit portion being configured to enable charge to be equalized between the opposing first and second faces of the piezoelectric convertor layer.

10. The apparatus of claim 9, wherein the first circuit portion comprises a storage capacitor configured to store the charge from the piezoelectric convertor layer.

11. The apparatus of claim 9, wherein the second circuit comprises a resistor, the resistor being configured to resist charge equalization between the opposing first and second faces of the piezoelectric convertor layer.

12. The apparatus of claim 9, wherein the apparatus is configured such that:

the resistance of the first piezoresistive layer is less than the resistance of the resistor when the piezoelectric convertor layer is compressed; and

the resistance of the first piezoresistive layer is greater than the resistance of the resistor when the piezoelectric convertor layer is not compressed.

13. The apparatus of claim 1, wherein the apparatus comprises a second piezoresistive layer overlying, and being in electrical communication with, the opposing second face of the piezoelectric convertor layer.

14. The apparatus of claim 13, wherein the apparatus is configured such that the resistance of the second piezoresistive layer increases in response to compression of the piezoelectric convertor layer.

15. The apparatus of claim 13, wherein the second piezoresistive layer comprises doped graphene in direct contact with the piezoelectric convertor, the resistance of the doped graphene being configured to change in response to an electric field being generated by the piezoelectric convertor in response to deformation.

16. The apparatus of claim 13, wherein the apparatus comprises:

a first circuit portion electrically connected to;

the first face of the piezoelectric convertor layer via the first piezoresistive layer; and

the opposing second face of the piezoelectric convertor,

the first circuit portion being configured to store charge generated by the piezoelectric convertor layer; and

a second circuit portion connected to;

the first face of the piezoelectric convertor layer; and

the opposing second face of the piezoelectric convertor layer via the second piezoresistive layer,

the second circuit portion being configured to enable charge to be equalized between the opposing first and second faces of the piezoelectric convertor layer.

17. The apparatus of claim 1, wherein the extent of the piezoresistive layer is smaller than the extent of the piezoelectric convertor layer.

18. The apparatus of claim 1, wherein the apparatus comprises a plurality of discrete, spaced apart first piezoresistive layers arranged in proximity with a common piezoelectric convertor layer.

19. The apparatus of claim 1, wherein the apparatus is or forms part of a touch screen, a touch screen pixel, a shoe, a watch, an item of clothing, a portable electronic device, or a mechanical energy collecting device.

20. A method of manufacturing an apparatus, the method comprising:

providing a piezoelectric convertor layer; and

providing a proximal first piezoresistive layer being in electrical communication with, a first face of the piezoelectric convertor layer,

the apparatus being configured such that when the piezoelectric convertor layer is deformed to generate charge, the proximal piezoresistive layer is configured to control the flow of charge from the piezoelectric convertor layer.

21. A method comprising:

generating charge, by a piezoelectric convertor layer being deformed,

wherein a first face of the piezoelectric convertor layer is in electrical communication with a proximal first piezoresistive layer; and

wherein in response to a deformation of the piezoelectric convertor layer the proximal piezo resistive layer is deformed and thereby controls the flow of charge from the piezoelectric convertor layer.