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US5218173A
Expired / Lapsed
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Shielding materials for electromagnetic digitizers
Assignee: International Business Machines Corp
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Filing: 1991-10-17
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Granted: 1993-06-08
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Expires: 2011-10-17
Abstract
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.
Inventors
- 👤 Richard L. Garwin
- 👤 Gregory F. Russell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:55
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/046
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
37 words
An electromagnetic digitizer, comprising: 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.
Claim 2
Dependent Claim
37 words
An electromagnetic digitizer, comprising: 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.
Claim 3
Dependent Claim
56 words
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.
Claim 4
Dependent Claim
57 words
An electromagnetic digitizer according to claim 1, wherein said sensor grid comprises a multiplicity of wires such that said wires form loops, and wherein said shield plate comprises a non-conductive material and the product of the magnetic permeability and the thickness of said non-conductive material is greater than the width of said loops in said sensor grid.
Claim 5
Dependent Claim
13 words
An electromagnetic digitizer according to claim 1, wherein said shield plate comprises Mumetal.
Claim 6
Dependent Claim
13 words
An electromagnetic digitizer according to claim 1, wherein said shield plate comprises ferrites.
Claim 7
Dependent Claim
29 words
An electromagnetic digitizer according to claim 1, wherein said sensor grid includes a sensor grid substrate; and said shield plate is in direct contact with said sensor grid substrate.
Claim 8
Dependent Claim
13 words
An electromagnetic digitizer according to claim 6, wherein said shield plate comprises Mumetal.
Claim 9
Dependent Claim
13 words
An electromagnetic digitizer according to claim 6, wherein said shield plate comprises ferrites.
Claim 10
Dependent Claim
67 words
An electromagnetic digitizer, comprising: 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.
Claim 11
Dependent Claim
67 words
An electromagnetic digitizer, comprising: 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.
Claim 12
Dependent Claim
13 words
An electromagnetic digitizer according to claim 9, wherein: said shield plate comprises copper.
Claim 13
Dependent Claim
13 words
An electromagnetic digitizer according to claim 9, wherein said shield plate comprises aluminum.
Claim 14
Dependent Claim
26 words
An electromagnetic digitizer according to claim 9, wherein the separation between said shield plate and said wires of said sensor grid is one millimeter or less.
Claim 15
Dependent Claim
13 words
An electromagnetic digitizer according to claim 12, wherein said shield plate comprises copper.
Claim 16
Dependent Claim
13 words
An electromagnetic digitizer according to claim 12, wherein said shield plate comprises aluminum.
Claim 17
Dependent Claim
37 words
An electromagnetic digitizer, comprising: 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.
Claim 18
Dependent Claim
37 words
An electromagnetic digitizer, comprising: 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.
Claim 19
Dependent Claim
13 words
An electromagnetic digitizer according to claim 15, wherein said magnetic material comprises ferrites.
Claim 20
Dependent Claim
13 words
An electromagnetic digitizer according to claim 16, wherein said conductive material comprises copper.
Claim 21
Dependent Claim
13 words
An electromagnetic digitizer according to claim 16, wherein said conductive material comprises aluminum.
Claim 22
Dependent Claim
35 words
An electromagnetic digitizer, comprising: 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.
Claim 23
Dependent Claim
35 words
An electromagnetic digitizer, comprising: 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.
Claim 24
Dependent Claim
15 words
An electromagnetic digitizer according to claim 19, wherein said shield material comprises a Nickel alloy.
Claim 25
Dependent Claim
13 words
An electromagnetic digitizer according to claim 19, wherein said shield plate comprises Mumetal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-07 | 1996-12-07 | 1997-06-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-07 | 2000-12-07 | 2001-06-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-07 | 2004-12-07 | 2005-06-08 | $7700.00 | Window Closed / Lapsed |