Force sensing device
A force sensing device comprises a sensing array comprising a first conductive layer having a plurality of conductive rows and a second conductive layer having a plurality of conductive columns. The plurality of conductive rows and plurality of conductive columns are arranged to define a plurality of intersections. The force sensing device also comprises an electro-active layer overlaying the first conductive layer and comprising a pressure sensitive element at each intersection. A force concentrating structure is positioned at each intersection on the second conductive layer.
1. A force sensing device comprising:
a sensing array comprising a first conductive layer and a second conductive layer;
said first conductive layer comprising a plurality of conductive rows and said second conductive layer comprising a plurality of conductive columns, said plurality of conductive rows and said plurality of conductive columns being arranged to define a plurality of intersections;
an electro-active layer overlaying said first conductive layer, said electro-active layer comprising a pressure sensitive element at each intersection of said plurality of intersections;
a force concentrating structure positioned at each intersection of said plurality of intersections on said second conductive layer, wherein said force concentrating structure provides a protrusion of said second conductive layer into an air gap between said first conductive layer and said second conductive layer; and
a cover layer laminated to said force sensing device by means of an adhesive layer, said adhesive layer comprising an adhesive and a plurality of openings in said adhesive.
2. The force sensing device of claim 1 , wherein said force concentrating structure comprises a dielectric material.
3. The force sensing device of claim 1 , wherein said force concentrating structure comprises a dielectric ink.
4. The force sensing device of claim 1 , wherein said force concentrating structure comprises a plurality of layers.
5. The force sensing device of claim 1 , wherein said force concentrating structure comprises an embossed substrate.
6. The force sensing device of claim 1 , wherein said pressure sensitive element comprises a quantum tunnelling material.
7. The force sensing device of claim 1 , further comprising a spacer layer comprising a plurality of spacer elements, wherein said plurality of openings are aligned with said plurality of spacer elements to create an air gap between said cover layer and a supporting substrate of said force sensing device.
8. The force sensing device of claim 1 , further comprising a spacer layer comprising a plurality of spacer elements.
9. The force sensing device of claim 1 , wherein a height of said force concentrating structure is at least six microns.
10. The force sensing device of claim 1 , further comprising a first array of force concentrating structures having a first height, and a second array of force concentrating structures having a second height, wherein said first height and said second height are substantially different.
11. An electronic device comprising the force sensing device of claim 1 .
12. A method of producing a force sensing device, comprising steps of:
printing a sensing array in the form of a first conductive layer comprising a plurality of conductive rows and a second conductive layer comprising a plurality of conductive columns, arranged to define a plurality of intersections;
printing an electro-active layer over said first conductive layer such that said electro-active layer comprises a pressure sensitive element at each intersection of said plurality of intersections;
providing a force concentrating structure at each intersection of said plurality of intersections on said second conductive layer to provide a protrusion of said second conductive layer into an air gap between said first conductive layer and said second conductive layer; and
laminating a cover layer to said force sensing device by means of an adhesive layer, said adhesive layer comprising an adhesive and a plurality of openings in said adhesive.
13. The method of claim 12 , wherein said step of providing a force concentrating structure comprises a step of:
depositing a dielectric material onto a substrate.
14. The method of claim 13 , wherein said step of depositing comprises printing a plurality of layers of dielectric material.
15. The method of claim 13 , wherein said step of depositing comprises providing a bead of dielectric material at each intersection of said plurality of intersections.
16. The method of claim 13 , wherein said step of depositing comprises providing a plurality of beads of dielectric material at each intersection of said plurality of intersections.
17. A method of producing a force sensing device, comprising steps of:
printing a sensing array in the form of a first conductive layer comprising a plurality of conductive rows and a second conductive layer comprising a plurality of conductive columns, arranged to define a plurality of intersections;
printing an electro-active layer over said first conductive layer such that said electro-active layer comprises a pressure sensitive element at each intersection of said plurality of intersections; and
providing a force concentrating structure at each intersection of said plurality of intersections on said second conductive layer to provide a protrusion of said second conductive layer into an air gap between said first conductive layer and said second conductive layer,
wherein said step of providing a force concentrating structure comprises a step of:
depositing a dielectric material onto a substrate, wherein said step of depositing comprises providing a bead of dielectric material at each intersection of said plurality of intersections.