Conductive element

• US 9,425,790 B2
• Filed: 01/27/2012
• Issued: 08/23/2016
• Est. Priority Date: 01/28/2011
• Status: Active Grant

• Current Assignee: Novalia Ltd
• Original Assignee: Novalia Ltd
• Inventors: Stone, Kate
• Primary Examiner(s): Leon, Edwin A.
• Assistant Examiner(s): Malakooti, Iman
• Application Number:
  US13/982,078
• Publication Number:
  US 20140021027A1
• Time in Patent Office: 1,670 Days
• Field of Search: 200/600, 200/46, 200/5.R
• US Class Current: 1/1
• CPC Class Codes: H03K 17/955 using a capacitive detector
• CPC Class Codes: H03K 17/962 Capacitive touch switches
• CPC Class Codes: H03K 17/9622 using a plurality of detectors, e.g. keyboard
• CPC Class Codes: H03K 2017/9602 characterised by the type or shape of the sensing electrodes
• CPC Class Codes: H03K 2217/96019 using conductive paint
• CPC Class Codes: H03K 2217/96058 Fail-safe touch switches, where switching takes place only after repeated touch
• CPC Class Codes: H03K 2217/960755 Constructional details of capacitive touch and proximity switches

Abstract

A conductive element which can serve as capacitive sensing element comprises a conductive pad comprising relatively low conductivity material, such as carbon-based ink, and a conductive mesh comprising relatively high conductivity material, such as silver-based ink, underlying or overlying the pad to form a composite conductive element.

Claims

1. A printed article comprising:

a substrate; and

at least one capacitive touch switch supported on the substrate;

wherein each capacitive touch switch comprises;

a conductive pad comprising relatively low conductivity material; and

a conductive mesh comprising relatively high conductivity material underlying or overlying the pad and being in contact with the pad so as to form a composite conductive element,

wherein the conductive mesh includes open areas without the relatively high conductivity material, each open area being a least 20 mm².

2. A printed article according to claim 1, wherein the conductive pad has a sheet resistance of at least 1 kΩ

sq<sup>−

1</sup>, at least 2 kΩ

sq<sup>−

1</sup> or at least 5 kΩ

sq<sup>−

1</sup>.

3. A printed article according to claim 1, wherein the conductive pad has a sheet resistance of at least at least 10 k Ω

sq<sup>−

1</sup>, at least 20 kΩ

sq<sup>−

1</sup> or at least 50 kΩ

sq<sup>−

1</sup>.

4. A printed article according to claim 1, wherein the conductive mesh has a sheet resistance of no more than 50 Ω

sq<sup>−

1</sup>, no more than 20 Ω

sq<sup>−

1</sup> or no more than 10 Ω

sq<sup>−

1</sup>.

5. A printed article according to claim 1, wherein the conductive mesh has a sheet resistance of no more than 5 Ω

sq<sup>−

1</sup>, no more than 2 Ω

sq<sup>−

1</sup> or no more than 1 Ω

sq<sup>−

1</sup>.

6. A printed article according to claim 1, wherein the conductive pad comprises conductive ink.

7. A printed article according to claim 1, wherein the conductive pad comprises a carbon-based conductive ink.

8. A printed article according to claim 1, wherein the conductive mesh comprises a conductive ink.

9. A printed article according to claim 1, wherein the conductive mesh comprises a metal-based conductive ink.

10. A printed article according to claim 9, wherein the conductive mesh comprises a silver-based conductive ink.

11. A printed article according to claim 1, wherein the conductive mesh comprises a conductive foil.

12. A printed article according to claim 1, wherein the capacitive touch switch has a surface area of at least 100 mm², at least 200 mm² or at least 500 mm².

13. A printed article according to claim 1, wherein the capacitive touch switch has a surface area of at least 1,000 mm², at least 2,000 mm² or at least 5,000 mm².

14. A printed article according to claim 1, wherein the capacitive touch switch has a surface area of no more than 5,000 mm², no more than 10,000 mm² or no more than 20,000 mm².

15. A printed article according to claim 1, wherein the conductive pad comprises a layer which is a solid block.

16. A printed article according to claim 1, wherein the conductive pad has a thickness of at least 1 μ

m, at least 2 μ

m, at least 5 μ

m or at least 10 μ

m.

17. A printed article according to claim 1, wherein the conductive pad has a thickness no more than 5 μ

m or no more than 10 μ

m.

18. A printed article according to claim 1, wherein the conductive mesh has a thickness of at least 1 μ

m, at least 2 μ

m, at least 5 μ

m or at least 10 μ

m.

19. A printed article according to claim 1, wherein the conductive mesh has a thickness of no more than 5 μ

m or no more than 10 μ

m.

20. A printed article according to claim 1, wherein the conductive mesh comprises tracks having a width of at least 100 μ

m, at least 200 μ

m or at least 500 μ

m.

21. A printed article according to claim 1, wherein the conductive mesh comprises tracks having a width no more than 1 mm, no more than 2 mm or no more than 5 mm.

22. A printed article according to claim 1, wherein the conductive mesh comprises tracks having a width of at least 1 mm, at least 2 mm or at least 5 mm.

23. A printed article according to claim 1, wherein the mesh comprises an array of tracks.

24. A printed article according to claim 1, wherein the mesh comprises a circular array of tracks.

25. A printed article according to claim 24, wherein the circular array comprises at least one annular track.

26. A printed article according to claim 25, wherein there are at least three annular tracks, at least four annular tracks, at least five annular tracks, at least six annular tracks, at least seven annular track, at least eight annular tracks, at least nine annular tracks or at least ten annular tracks.

27. A printed article according to claim 25, wherein the circular array comprises at least one radial track.

28. A printed article according to claim 27, wherein at least two pairs of radial tracks are equally spaced apart angularly.

29. A printed article according to claim 1, wherein the substrate comprises paper.

30. A printed article according to claim 1, wherein the substrate comprises card.

31. A printed article according to claim 1, wherein the substrate comprises a polymer.

32. A printed article according to claim 1, further comprising:

a microcontroller; and

a set of at least one conductive elements operationally connected to the microcontroller.