Electrodes having surface exclusions
Electrodes having an active region formed of a plurality of layers in which one or more conductive layers is formed of a pattern having a plurality of branches and/or holes (e.g. a grid pattern, a snowflake pattern, etc.) to provide a greater density of edges, so that the ratio of edges in the patterned conductive layer to the perimeter of the active region is greater than a minimum value (e.g., 1.5, 2, 3, 4, 5, 6, etc.). The multiple layers may include the patterned conductive layer and a second conductive layer, which may also be patterned, with a less conductive layer sandwiched between them to achieve a more even charge distribution across the face of the active region than in addition to the greater current density provided by the large number of edges.
1. An electrode for transdermal electrical stimulation, the electrode comprising:
a substrate; and
a multi-layered active region comprising:
a first layer on the substrate that is electrically contiguous and conductive and is arranged in a pattern forming a plurality of one or more combinations of branches and voids, wherein the pattern extends through a width of the first layer,
a second layer on the first layer,
a third layer that is electrically contiguous and conductive on the second layer,
wherein the second layer is sandwiched between the first and third layers and has a resistivity that is greater than 5× the resistivity of the first or third layers;
wherein a ratio of edges formed by the pattern of the first layer to a perimeter of the multi-layered active region is greater than 4.
2. The electrode of claim 1 , wherein the substrate is planar.
3. The electrode of claim 1 , wherein the substrate is Polyethylene Terephthalate (PET).
4. The electrode of claim 1 , further comprising a conductive via between the first layer and an electrical connector configured to connect the electrode to an electrical stimulator.
5. The electrode of claim 4 , wherein the electrical connector comprises a snap connector.
6. The electrode of claim 1 , further comprising a second multi-layered active region on the substrate.
7. The electrode of claim 1 , wherein the first layer is arranged in a grid pattern.
8. The electrode of claim 1 , wherein the first layer is arranged in a snowflake pattern.
9. The electrode of claim 1 , wherein the first layer comprises a layer of silver (Ag).
10. The electrode of claim 1 , wherein the second layer comprises a conductive carbon layer.
11. The electrode of claim 1 , wherein the second layer has a resistance that is greater than 10× a resistance of the first layer or the third layer.
12. The electrode of claim 1 , wherein the third layer comprises Ag/AgCl.
13. The electrode of claim 1 , wherein the third layer overlaps the second layer and wherein the second layer overlaps the third layer.
14. The electrode of claim 1 , wherein the ratio of edges formed by the pattern of the first layer to the perimeter of the multi-layered active region is greater than 10.
15. The electrode of claim 1 , wherein the ratio of edges formed by the pattern of the first layer to the perimeter of the multi-layered active region is greater than 15.
16. The electrode of claim 1 , further comprising a hydrogel covering the third layer.
17. The electrode of claim 1 , wherein the third layer is arranged in a pattern forming a plurality of one or more combinations of branches and voids, wherein the pattern extends through a width of the third layer.
18. An electrode for transdermal electrical stimulation, the electrode comprising:
a planar substrate; and
a multi-layered active region comprising:
a first layer on the substrate that is electrically contiguous and conductive and is arranged in a contiguous pattern forming a plurality of one or more combinations of branches and voids, wherein the pattern extends through a width of the first layer,
a second layer on the first layer,
a third layer that is electrically contiguous and conductive on the second layer, and
a hydrogel covering the third layer,
wherein the second layer is sandwiched between the first and third layers and has a resistivity that is greater than 10× the resistivity of the first or third layers;
wherein a ratio of edges formed by the first layer to a perimeter of the multi-layered active region is greater than 4.
19. An electrode for transdermal electrical stimulation, the electrode comprising:
a planar substrate; and
a multi-layered active region comprising:
a first layer on the substrate comprising an electrically contiguous and conductive Ag layer that is arranged in a contiguous pattern forming a plurality of one or more combination of branches and voids, wherein the pattern extends through a width of the first layer,
a second layer comprising a conductive carbon layer on the first layer,
a third layer comprising a contiguous Ag/AgCl conductive layer on the second layer, and
a hydrogel covering the third layer,
wherein the second layer is sandwiched between the first and third layers and has a resistivity that is greater than 10× the resistivity of the first or third layers;
wherein a ratio of edges formed by the first layer to a perimeter of the multi-layered active region is greater than 4.