FORCE SENSING SHEET
First Claim
1. A support apparatus comprising:
- a cushion having a plurality of air bladder cells;
an elastically stretchable sheet positioned on top of the air bladder cells;
a plurality of first conductive paths supported on the elastically stretchable sheet;
a layer of sensing material positioned in contact with the first conductive paths, the layer of sensing material having an electrical characteristic that varies in response to physical forces exerted thereon;
a layer of semiconductive material positioned in contact with the layer of sensing material on a side of the layer of sensing material opposite the plurality of first conductive paths; and
a plurality of second conductive paths positioned in contact with the layer of semiconductive material on a side of the layer of semiconductive material opposite the layer of sensing material.
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Accused Products
Abstract
A support apparatus includes a force sensing array positioned thereon that includes multiple layers of material that are arranged to define an elastically stretchable sensing sheet. The sensing sheet may be placed underneath a patient to detect interface forces or pressures between the patient and the support structure that the patient is positioned on. The force sensing array includes a plurality of force sensors. The force sensors are defined where a row conductor and a column conductor approach each other on opposite sides of a force sensing material, such as a piezoresistive material. In order to reduce electrical cross talk between the plurality of sensors, a semiconductive material is included adjacent the force sensing material to create a PN junction with the force sensing material. This PN junction acts as a diode, limiting current flow to essentially one direction, which, in turn, reduces cross talk between the multiple sensors.
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Citations
13 Claims
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1. A support apparatus comprising:
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a cushion having a plurality of air bladder cells; an elastically stretchable sheet positioned on top of the air bladder cells; a plurality of first conductive paths supported on the elastically stretchable sheet; a layer of sensing material positioned in contact with the first conductive paths, the layer of sensing material having an electrical characteristic that varies in response to physical forces exerted thereon; a layer of semiconductive material positioned in contact with the layer of sensing material on a side of the layer of sensing material opposite the plurality of first conductive paths; and a plurality of second conductive paths positioned in contact with the layer of semiconductive material on a side of the layer of semiconductive material opposite the layer of sensing material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification