Magnetic shield for use in a location sensing system
An energy transfer apparatus with a magnetic shield is configured to magnetically couple energy from a fixed location to a mobile or moveable device within a field-activated space of the energy transfer apparatus. Apparatuses include a location sensing surface and a drive coil arranged in relation to a periphery of the location sensing surface. A magnetic shield plate is disposed below the location sensing surface and the drive coil. The shield plate includes a number of radially oriented slots originating at, and distributed about, a periphery of the shield plate.
1. An apparatus, comprising:
a location sensing surface;
a drive coil arranged in relation to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate comprising a plurality of radially oriented slots originating at, and distributed about, a periphery of the shield plate,
wherein the shield plate has relatively low reluctance along a first direction, and the shield plate has relatively high reluctance along a second direction, wherein the first direction is approximately orthogonal to the second direction.
2. An apparatus, comprising:
a location sensing surface;
a drive coil arranged in relation to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate comprising a plurality of radially oriented slots originating at, and distributed about, a periphery of the shield plate,
wherein the shield plate has relatively low reluctance along a radial direction, and the shield plate has relatively high reluctance along a circumferential direction.
3. An apparatus, comprising:
a location sensing surface;
a drive coil arranged in relation to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate comprising a plurality of radially oriented slots originating at, and distributed about, a periphery of the shield plate,
wherein the shield plate has relatively low electrical resistance along a first direction, and the shield plate has relatively high electrical resistance along a second direction, wherein the first direction is approximately orthogonal to the second direction.
4. An apparatus, comprising:
a location sensing surface;
a drive coil arranged in relation to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate comprising a plurality of radially oriented slots originating at, and distributed about, a periphery of the shield plate,
wherein the shield plate has relatively low electrical resistance along a radial direction, and the shield plate has relatively high electrical resistance along a circumferential direction.
5. An apparatus, comprising:
a location sensing surface;
a drive coil arranged in relation to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate comprising a plurality of radially oriented slots originating at, and distributed about, a periphery of the shield plate,
wherein the shield plate has relatively low reluctance along a first direction, and the shield plate has relatively high electrical resistance along a second direction, wherein the first direction is approximately orthogonal to the second direction.
6. The apparatus of claim 5 , wherein first and second directions vary relative to one another across a surface of the shield plate.
7. The apparatus of claim 5 , wherein first direction is oriented in alignment with a direction of a magnetic field generated by the drive coil.
8. An apparatus, comprising:
a location sensing surface;
a drive coil arranged in relation to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate comprising a plurality of radially oriented slots originating at, and distributed about, a periphery of the shield plate,
wherein the shield plate has relatively low reluctance along a radial direction, and the shield plate has relatively high electrical resistance along a circumferential direction.
9. An apparatus, comprising:
a location sensing surface;
a drive coil arranged in relation to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate comprising a plurality of radially oriented slots originating at, and distributed about, a periphery of the shield plate,
wherein at least some of the slots have a curved portion situated near or at the drive coil, the curved portion oriented substantially perpendicular to the drive coil.
10. An apparatus, comprising:
a location sensing surface;
a drive coil disposed relative to a periphery of the location sensing surface; and
a magnetic shield plate disposed below the location sensing surface and the drive coil, the shield plate formed to provide a relatively low reluctance and electrical resistance in a first direction, and a relatively high reluctance and electrical resistance in a second direction, the second direction differing from the first direction.
11. The apparatus of claim 10 , wherein the first direction is a substantially radially inward direction relative to a periphery of the shield plate, and the second direction is a substantially circumferential direction relative to the periphery of the shield plate.
12. The apparatus of claim 10 , wherein the first direction is substantially orthogonal to the second direction.
13. The apparatus of claim 10 , wherein the first and second directions change relative to one another as a function of position across a surface of the shield plate.
14. The apparatus of claim 10 , wherein the first direction is oriented generally in alignment with a direction of a magnetic field generated by the drive coil.
15. The apparatus of claim 10 , wherein the drive coil is arranged in a substantially circular or rectangular shape.
16. The apparatus of claim 10 , wherein the shield plate comprises a bent portion extending along the periphery of the shield plate.
17. The apparatus of claim 10 , wherein the reluctance associated with the first and second directions differ by a factor of 5:1 or greater.
18. The apparatus of claim 10 , wherein the electrical resistance associated with the first and second directions differ by a factor of 5:1 or greater.