Digitizer tablet having high permeability grid shield
First Claim
1. In a digitizer tablet having conductive grids on a substrate, the improvement to reduce weight and thickness while improving signal strength and shielding characteristics comprising:
- a) a shield member disposed one of (i) in contact with, and (ii) spaced from the substrate, and parallel thereto, said shield member being of a metal having a high magnetic permeability; and
wherein,b) the substrate comprises a pair of rigid substrates disposed in spaced parallel planes, one rigid substrate having the conductive grids thereon and one rigid substrate having interconnects thereon; and
,c) said shield member is disposed between said pair of rigid substrates.
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Accused Products
Abstract
A combined shield member and grid shield for a digitizer tablet having conductive grids on a flexible substrate comprising a sheet of a metal having a high magnetic permeability substantially the size of a square X-Y axis coordinate system of the digitizer tablet shielding the flexible substrate. Preferably, the metal has an initial permeability of at least 5,000. The metal can be a NiFe alloy having an initial permeability sufficiently high to qualify it as a μ-metal. Typically, the sheet of metal is a square sheet of substantially the size of a square X-Y axis coordinate system of the digitizer tablet and the flexible substrate has edge portions which extend beyond side edges of the sheet of metal and are wrapped around the side edges. An alternate embodiment employs the high permeability shield positioned between two rigid substrates carrying the grids and interconnects respectively. A conductive metal foil over the surface of the substrate corrects any signal errors introduced by the shield. The foil can also be grounded for electostatic shielding.
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Citations
33 Claims
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1. In a digitizer tablet having conductive grids on a substrate, the improvement to reduce weight and thickness while improving signal strength and shielding characteristics comprising:
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a) a shield member disposed one of (i) in contact with, and (ii) spaced from the substrate, and parallel thereto, said shield member being of a metal having a high magnetic permeability; and
wherein,b) the substrate comprises a pair of rigid substrates disposed in spaced parallel planes, one rigid substrate having the conductive grids thereon and one rigid substrate having interconnects thereon; and
,c) said shield member is disposed between said pair of rigid substrates. - View Dependent Claims (3, 4)
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2. In a digitizer tablet having conductive grids on a substrate, the improvement to reduce weight and thickness while improving signal strength and shielding characteristics comprising:
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a) a shield member disposed one of (i) in contact with, and (ii) spaced from the substrate, and parallel thereto, said shield member being of a metal having a high magnetic permeability; and
,b) a low resistance, eddy current-developing conductive material disposed over an outer surface of the substrate whereby signal errors caused by said shield member are reduced. - View Dependent Claims (5, 6, 7)
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8. A high efficiency digitizer tablet for use with a cordless electro-magnetic transmitting cursor to reduce required signal strength from the cursor and extend battery life thereof comprising:
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a) a flexible substrate having a pattern of conductive grids thereon; b) a support member of metal having a high magnetic permeability supporting said flexible substrate; and
,c) a low resistance, eddy current-developing conductive material disposed over an outer surface of the substrate whereby signal errors caused by said support member are reduced. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A combined support member and grid shield for a digitizer tablet having conductive grids on a flexible substrate comprising:
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a) a sheet of a metal having a high magnetic permeability substantially the size of a square X-Y axis coordinate system of the digitizer tablet supporting the flexible substrate; and
,b) a low resistance, eddy current-developing conductive material disposed over an outer surface of the substrate whereby signal errors caused by said sheet of metal are reduced. - View Dependent Claims (15, 16, 17, 32, 33)
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18. In a digitizer tablet having conductive grids on a substrate for use with a powered cursor emitting a magnetic signal detected in the conductive grids, the improvement for increasing useful signal strength and decreasing power requirements in the cursor comprising:
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a) a shield member disposed one of (i) in contact with, and (ii) spaced from the substrate, and parallel thereto, said shield member being of a metal having a high magnetic permeability; and
wherein,b) the substrate comprises a pair of rigid substrates disposed in spaced parallel planes, one rigid substrate having the conductive grids thereon and one rigid substrate having interconnects thereon; and
,c) said shield member is disposed between said pair of rigid substrates.
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19. In a digitizer tablet having conductive grids on a substrate for use with a powered cursor emitting a magnetic signal detected in the conductive grids, the improvement for increasing useful signal strength and decreasing power requirements in the cursor comprising:
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a) a shield member disposed one of (i) in contact with, and (ii) spaced from the substrate, and parallel thereto, said shield member being of a metal having a high magnetic permeability; and
,b) a low resistance, eddy current-developing conductive material disposed over an outer surface of the substrate whereby signal errors caused by said shield member are reduced. - View Dependent Claims (20, 21, 22, 23, 24, 25)
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26. A high efficiency digitizer tablet for use with a cordless electro-magnetic transmitting cursor to reduce required signal strength from the cursor and extend battery life thereof comprising:
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a) a first rigid planar substrate having a pattern of conductive grids thereon; and
,b) a second rigid planar substrate having interconnects thereon disposed parallel to and spaced from said first rigid planar substrate; and
,c) a shield member of a metal having a high magnetic permeability disposed between said first rigid planar substrate and said second rigid planar substrate. - View Dependent Claims (27, 28, 29, 30, 31)
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Specification