Mesh patterns for touch sensor electrodes

• US 9,459,751 B2
• Filed: 11/24/2015
• Issued: 10/04/2016
• Est. Priority Date: 11/30/2012
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Weaver, Billy L., Barton, Roger W., Herdtle, Thomas, Hable, Brock A.
• Primary Examiner(s): Bibbins, Latanya
• Application Number:
  US14/950,826
• Publication Number:
  US 20160077637A1
• Time in Patent Office: 315 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04108 Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• 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 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0448 Details of the electrode shape, e.g. for enhancing the detection of touches, for generating specific electric field shapes, for enhancing display quality

Abstract

An electrode for a touch sensitive device includes micro-wire conductors arranged to define an electrically continuous electrode trunk area, and including branching elements which extend outward from the electrode trunk area. The electrically continuous trunk area is patterned coincident an underlying reference mesh pattern, as are the branching elements.

Claims

1. An electrode for a touch sensor, comprising

an array of discontinuous metallic micro-wire conductors establishing a reference mesh having a characteristic average cell spacing;

a first conductive pattern of continuous metallic micro-wires disposed along a first direction,

wherein the conductive pattern is coincident with the reference mesh; and

,

a plurality of electrically continuous branching elements electrically connected to the first conductive pattern and extending outward therefrom,

wherein the branching elements are coincident with the reference mesh and are comprised of metallic micro-wires, and

wherein the branching elements include a plurality of different lengths.

2. The electrode of claim 1, wherein the first conductive pattern defines an electrode trunk, and the branching elements extend outward from the electrode trunk.

3. The electrode of claim 2, wherein the first conductive pattern defines further electrode trunks, and the branching elements extend outward from these further electrode trunks.

4. The electrode of claim 2, wherein the branching elements substantially conform to a diamond shape centered on the electrode trunk.

5. The electrode of claim 2, wherein branching elements are electrically coupled to the electrode trunk at no more than one terminal area.

6. The electrode of claim 1, wherein the branching elements are arranged along directions substantially transverse to the first direction.

7. The electrode of claim 1, wherein a distance between branching elements is equal to or greater than at least one characteristic average cell spacing.

8. The electrode of claim 1, wherein a length of each of the branching elements is equal to or greater than at least one characteristic average cell spacing.

9. The electrode of claim 1, wherein at least some of the branching elements are interleaved with branching elements of other electrodes of the touch sensor.

10. The electrode of claim 1, wherein the reference mesh is comprised of microwires having trace widths of about X+0.5 in units of micrometers;

and an open area fraction between about [95−

X]% and 99.5%, wherein 0≦

X≦

4.5.

11. A touch sensor comprising the electrode of claim 1.

12. A touch sensor comprising first and second electrode layers separated by a dielectric layer, the first and second electrode layers each comprising a plurality of electrodes, at least some electrodes of the first electrode layer comprising:

a first array of discontinuous metallic micro-wire conductors establishing a first reference mesh;

a first conductive pattern of continuous metallic micro-wires disposed along a first direction,

wherein the first conductive pattern is coincident with the first reference mesh; and

a first plurality of electrically continuous branching elements electrically connected to the first conductive pattern and extending outward therefrom, wherein the first plurality of branching elements are coincident with the first reference mesh and are comprised of metallic micro-wires,

wherein at least some of the branching elements the first plurality of branching elements are interleaved with branching elements of other electrodes of the first electrode layer.

13. The touch sensor of claim 12, wherein the branching elements include a plurality of different lengths.

14. The touch sensor of claim 12, wherein a distance between branching elements is equal to or greater than at least one characteristic average cell spacing.

15. The touch sensor of claim 12, wherein a length of each of the branching elements is equal to or greater than at least one characteristic average cell spacing.

16. The touch sensor of claim 12, wherein at least some electrodes of the second electrode layer comprises:

a second array of discontinuous metallic micro-wire conductors establishing a second reference mesh;

a second conductive pattern of continuous metallic micro-wires disposed along a second direction, wherein the second conductive pattern is coincident with the second reference mesh; and

a second plurality of electrically continuous branching elements electrically connected to the second conductive pattern and extending outward therefrom, wherein the second plurality of branching elements are coincident with the second reference mesh and are comprised of metallic micro-wires.

17. The touch sensor of claim 16, wherein at least some of the branching elements in the second plurality of branching elements are interleaved with branching elements of other electrodes of the second electrode layer.

18. The touch sensor of claim 16, wherein the second direction is substantially transverse to the first direction.

19. The touch sensor of claim 16, wherein the branching elements in the second plurality of branching elements include a plurality of different lengths.

20. The touch sensor of claim 12, wherein the first reference mesh is comprised of microwires having trace widths of about X+0.5 in units of micrometers;

and an open area fraction between about [95−

X]% and 99.5%, wherein 0≦

X≦

4.5.

21. A display comprising the touch sensor of claim 12 overlaying a viewable portion of the display.