Detecting mechanical interactions

• US 6,504,531 B1
• Filed: 01/18/2001
• Issued: 01/07/2003
• Est. Priority Date: 05/20/1999
• Status: Expired due to Term

• Current Assignee: Wearable Technologies Ltd. (Blackline Safety Corp.)
• Original Assignee: Eleksen Limited (Peratech Limited)
• Inventors: Sandbach, David L.
• Primary Examiner(s): Liang, Regina
• Application Number:
  US09/743,964
• Time in Patent Office: 719 Days
• Field of Search: 345/173, 345/174, 345/178, 178/18.01, 178/18.03, 178/18-5-, 338/99, 338/208
• US Class Current: 345/173
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: H01H 2203/0085 Layered switches integrated into garment, clothes or textile
• CPC Class Codes: H01H 2203/01 Woven wire screen
• CPC Class Codes: H01H 9/0235 specially adapted for remote control, e.g. of audio or video apparatus

Abstract

A fabric-made position detector has a first fabric electrically conducting layer and a second fabric electrically conducting layer. The first electrically conducting layer has a first electrical contact and a second electrical contact and a second electrically conducting layer has a third electrically conducting contact and a fourth electrically conducting contact. Potential is applied across the first contact and the third contact to produce a first current and a potential is then applied across the second contact and the fourth contact to produce a second current. The first current is measured to produce a first current value and the second current is measured to produce a second current value. The first value and the second value are processed in combination to produce a property value indicating a property of the mechanical interaction.

Claims

1. A fabric-made position detector comprising:

a first fabric electrically conducting layer;

wherein said first electrically conducting layer has a first electrical contact and a second electrical contact and said second electrically conducting layer has a third electrically conducting contact and a fourth electrically conducting contact;

potential applying means (a) for applying potential across said first contact and said third contact while said second and fourth contacts are disconnected to produce a first current and (b) for applying a potential across said second contact and said fourth contact while said first and third contacts are disconnected to produce a second current;

current measuring means for measuring said first current to produce a first current value and for measuring said second current to produce a second current value; and

processing means configured to produce a property value indicating a property of a mechanical interaction by processing said first current value in combination with said second current value.

2. A fabric-made position detector according to claim 1, wherein said first fabric electrically conducting layer and/or said second fabric electrically conducting layer have different conductivities in different directions.

3. A fabric-made position detector according to claim 2, wherein layer conductivity of said first layer in a first direction connecting said first contact with said second contact is lower than the conductivity in a second direction perpendicular to said first direction.

4. A fabric-made position detector according to claim 2, wherein said different conductivities are achieved by using different yarns having different conductivities.

5. A fabric-made position detector according to claim 2, wherein said different conductivities are achieved by using different mixtures of conducting and non-conducting yarn.

6. A fabric-made position detector according to claim 1, wherein said property value is determined as an average of said first current value and said second current value.

7. A fabric-made position detector according to claim 1, wherein said property value is determined by combining a reciprocal of said first current value with a reciprocal of said second current value.

8. A fabric-made position detector according to claim 1, wherein

a central layer is disposed between said first fabric electrically conducting layer and said second fabric electrically conducting layer, said central layer including conducting means;

a first insulating separating means disposed between said first conductive layer and said conducting means; and

a second insulating separating means disposed between said second conductive layer and said conducting means;

wherein

said conducting means provides a conductive path between said first conducting layer and said second conducting layer at the position of a mechanical interaction.

9. A fabric-made position detector according to claim 8, wherein said first insulating means comprises a first separate insulating layer and said second insulating means comprises a second separate insulating layer.

10. A fabric-made position detector according to claim 1, further including

a compressible inner layer disposed between said first fabric conducting layer and said second fabric conducting layer having a plurality of conductive fibres or particles such that a conductive path is provided through said fibres or particles when said insulating material is placed in compression.

11. A method of detecting a mechanical interaction with respect to a position detecting device, wherein said position detecting device is configured to detect the position of a mechanical interaction by measuring electrical potentials applied across electrically conducting layers, characterised by the steps of

measuring a first current when an electrical potential is applied between a first contact of a first conducting layer and a third contact of a second conducting layer while disconnecting connections to a second contact of the first conducting layer and a fourth contact of said second conducting layer;

measuring a second current when an electrical potential is applied between said second and said fourth contacts while disconnecting connections to said first and said third contacts; and

processing said first current measurement in combination with said second current measurement to derive an output indicative of a characteristic of said mechanical interaction.

12. A method of detecting mechanical interaction according to claim 11, wherein said first fabric electrically conducting layer and/or said second fabric electrically conducting layer have different conductivities in different directions.

13. A method according to claim 12, wherein layer conductivity of said first layer in a first direction connecting said first contact with said second contact is lower than conductivity in the second direction perpendicular to said first direction.

14. A method according to claim 12, wherein said different conductivities are achieved by using different yarns having different conductivities.

15. A method according to claim 12, wherein said different conductivities are achieved by using different mixtures of conducting and non-conducting yarn.

16. A method according to claim 11, wherein said property value is determined as an average of said first current value and said second current value.

17. A method according to claim 11, wherein said property value is determined by combining reciprocals of measured values.

18. A method of detecting a mechanical interaction according to claim 11, wherein

a central layer is disposed between said first fabric electrically conducting layer and said second fabric electrically conducting layer, said central layer including conducting means;

a first insulating separating means disposed between said first conductive layer and said conducting means; and

a second insulating separating means disposed between said second conductive layer and said conducting means;

wherein

said conducting means provides a conductive path between said first conducting layer and said second conducting layer at the position of a mechanical interaction.

19. A method according to claim 18, wherein said first insulating means comprises a first separate insulating layer and said second insulating means comprises a second separate insulating layer.

20. A method according to claim 11, further including a compressible inner layer disposed between said first fabric conducting layer and said second fabric conducting layer having a plurality of conductive fibres or particles such that a conductive path is provided through said fibres or particles when said insulating material is placed in compression.