Shielding materials for electromagnetic digitizers
First Claim
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1. An electromagnetic digitizer, comprising:
- a sensor grid, anda shield plate disposed under said sensor grid, wherein said shield plate comprises a material with sufficiently high magnetic permeability to increase the magnetic signal in said sensor grid.
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Abstract
Shielding materials used in electromagnetic digitizers which are packaged in a notebook computer environment. Shielding materials with sufficiently high magnetic permeability to increase the magnetic signal detected by the digitizer sensor grid can be used in such an environment, and can be placed in direct contact with the sensor grid. Aluminum or copper shields can also be placed in direct contact with the sensor grid to provide the requisite shielding. A combination of conductive and ferrite material can also be used as the conductive base material provides for shielding and a layer of ferrite material increases the magnetic signal and prevents signal attenuation by the conductor.
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Citations
21 Claims
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1. An electromagnetic digitizer, comprising:
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a sensor grid, and a shield plate disposed under said sensor grid, wherein said shield plate comprises a material with sufficiently high magnetic permeability to increase the magnetic signal in said sensor grid. - View Dependent Claims (3, 4, 5, 6, 7, 8)
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2. An electromagnetic digitizer according to claim wherein
said sensor grid comprises a multiplicity of wires such that said wires form loops, and wherein said shield plate comprises a conductive material and the product of the magnetic permeability and skin depth of said conductive material is greater than the width of said loops in said sensor grid.
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9. An electromagnetic digitizer, comprising:
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a sensor grid comprising a multiplicity of wires, a pen comprising a pen coil, and a shield plate disposed under said sensor grid, wherein said shield plate comprises conductive material such that said conductive material is of sufficient thickness and conductivity to prevent penetration of the magnetic field of said pen coil, said shield plate being in contact with said sensor grid substrate. - View Dependent Claims (10, 11, 12, 13, 14)
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15. An electromagnetic digitizer, comprising:
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a shield plate disposed under a sensor grid, wherein said shield plate comprises a base material of conductive material with a layer of magnetic material disposed on one side of said base material. - View Dependent Claims (16, 17, 18)
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19. An electromagnetic digitizer, comprising:
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a shield plate disposed under a sensor grid, wherein said shield plate comprises a material that increases the magnetic signal in said sensor grid and which prevents penetration of magnetic fields. - View Dependent Claims (20, 21)
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Specification