Steering capaciflector sensor
First Claim
1. A capacitive type proximity sensor having substantial range and sensitivity between a machine and an intruding object in the immediate vicinity of the machine and a steerable sensing field, comprising:
- an outer electrical conductor on said machine forming one electrode of a sensor capacitor, the other electrode comprising said object, said outer conductor comprising a first thin sheet of conductive material;
a plurality of intermediate electrical conductors located between said outer conductor and said machine, said plurality of intermediate electrical conductors in close proximity to each other, said plurality of intermediate electrical conductors together comprising a surface having a size substantially larger than said outer conductor acting as a shield for reducing the parasitic capacitance between said outer conductor and said machine, said plurality of intermediate conductors comprising a plurality of thin sheets of conductive material together substantially wider than said first conductor;
said outer and plurality of intermediate conductors attached to a surface on said machine with no gap between said conductors and no gap between said surface and said plurality of intermediate conductors, the surfaces of said outer and plurality of intermediate conductors conjoining with each other and said surface of said machine, said conductors being electrically isolated from one another and said surface of said machine acting as a ground plane;
first circuit means for coupling, in phase and with variable gain, the instantaneous voltage at said outer electrical conductor to said plurality of intermediate electrical conductors;
second circuit means coupled to said outer conductor and being responsive to the capacitance of said sensor capacitor for generating a control signal to said machine.
1 Assignment
0 Petitions
Accused Products
Abstract
A capacitive type proximity sensor having substantial range and sensitivity between a machine and an intruding object in the immediate vicinity of the machine and having a steerable sensing field has an outer electrical conductor on the machine forming one electrode of a sensor capacitor, the other electrode is the object. The outer conductor is a thin sheet of conductive material with a pair (or more) of intermediate electrical conductors located between the outer conductor and the machine. The pair of intermediate electrical conductors are in close proximity to each other and together form a surface having a size substantially larger than the outer conductor to act as a shield for reducing the parasitic capacitance between the outer conductor and the machine and to steer the sensor field. The pair of intermediate conductors are thin sheets of conductive material substantially wider than the first conductor. The outer and pair of intermediate conductors are attached to a surface on the machine in electrical isolation and with no gaps between the conductors and no gap between the surface and the pair of intermediate conductors. The outer and pair of intermediate conductors are also in conformance with each other and the surface of the machine, and the surface of the machine acts as a ground plane. Variable gain voltage follower circuits are used for coupling, in phase, the instantaneous voltage at the outer electrical conductor to the pair of intermediate electrical conductors and a signal generator is coupled to the outer conductor and is responsive to the capacitance of the sensor capacitor for generating a control signal to the machine.
95 Citations
10 Claims
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1. A capacitive type proximity sensor having substantial range and sensitivity between a machine and an intruding object in the immediate vicinity of the machine and a steerable sensing field, comprising:
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an outer electrical conductor on said machine forming one electrode of a sensor capacitor, the other electrode comprising said object, said outer conductor comprising a first thin sheet of conductive material; a plurality of intermediate electrical conductors located between said outer conductor and said machine, said plurality of intermediate electrical conductors in close proximity to each other, said plurality of intermediate electrical conductors together comprising a surface having a size substantially larger than said outer conductor acting as a shield for reducing the parasitic capacitance between said outer conductor and said machine, said plurality of intermediate conductors comprising a plurality of thin sheets of conductive material together substantially wider than said first conductor; said outer and plurality of intermediate conductors attached to a surface on said machine with no gap between said conductors and no gap between said surface and said plurality of intermediate conductors, the surfaces of said outer and plurality of intermediate conductors conjoining with each other and said surface of said machine, said conductors being electrically isolated from one another and said surface of said machine acting as a ground plane; first circuit means for coupling, in phase and with variable gain, the instantaneous voltage at said outer electrical conductor to said plurality of intermediate electrical conductors; second circuit means coupled to said outer conductor and being responsive to the capacitance of said sensor capacitor for generating a control signal to said machine. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification