Capacitive proximity detector for radiation imager position control
First Claim
1. A capacitive proximity detection system for positioning a movable imaging element support structure with respect to a subject, the proximity detection system comprising:
- a plurality of sensor plate elements disposed in a sensing pattern in a known spatial relationship with said movable imaging element support structure and further comprising a capacitive sensing processing unit;
a multiplexer coupled to said plurality of capacitive plate elements and adapted to selectively electrically couple said sensor element plates in one of a plurality of range sensing modality switching units, each of said range modality switching units comprising at least one of said sensor plate elements; and
said capacitive sensing processing unit being coupled to said sensor plate elements via said multiplexer so as to generate an electric field around said sensor plates and detect proximity of objects to said sensor plates as a function of capacitance between said sensor plates and said subject so as to generate a range-to-subject signal for use in positioning said imaging element support structure.
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Accused Products
Abstract
A capacitive proximity detection system for positioning a movable radiation imaging element support structure with respect to a subject includes a plurality of sensor plates disposed in a collar assembly around a portion of an imaging component disposed towards a subject; a multiplexer coupled to the plurality of capacitive plate elements and adapted to selectively electrically couple the sensor plate elements in one of a plurality of sensing range modalities; and a capacitive sensing processor coupled to the sensor plate elements via the multiplexer so as to detect proximity of object to the sensor plate as a function of the capacitance between the sensor plates and the subject. The imaging system typically further includes a shield system coupled to the multiplexer and disposed so as to focus the capacitive sensing of the sensor plate elements towards the subject. The shield system includes a plurality of shielding plate elements disposed in a shielding pattern that corresponds with the pattern of sensor plate elements in the collar assembly. The shield plate elements are coupled to the capacitive sensing processor to receive a shield plate feedback signal therefrom.
94 Citations
18 Claims
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1. A capacitive proximity detection system for positioning a movable imaging element support structure with respect to a subject, the proximity detection system comprising:
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a plurality of sensor plate elements disposed in a sensing pattern in a known spatial relationship with said movable imaging element support structure and further comprising a capacitive sensing processing unit; a multiplexer coupled to said plurality of capacitive plate elements and adapted to selectively electrically couple said sensor element plates in one of a plurality of range sensing modality switching units, each of said range modality switching units comprising at least one of said sensor plate elements; and said capacitive sensing processing unit being coupled to said sensor plate elements via said multiplexer so as to generate an electric field around said sensor plates and detect proximity of objects to said sensor plates as a function of capacitance between said sensor plates and said subject so as to generate a range-to-subject signal for use in positioning said imaging element support structure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A radiation imaging system comprising:
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a gantry arm having a radiation imaging system component mounted thereon, said gantry being movably coupled to a positioning device so as to dispose said radiation imaging system component in a selectable spaced relationship with respect to a subject; a collar assembly disposed around said radiation imaging system component on said gantry arm; a capacitive proximity detection system coupled to said positioning device so as to control the position thereof, the proximity detection system comprising; a plurality of sensor plate elements disposed in said collar assembly in a sensing pattern in a known spatial relationship with said movable imaging element support structure; a plurality of guard plate elements disposed in said collar assembly in a shielding pattern that corresponds to said sensing pattern so as to form a plurality of guard-sensor plate pairs; a multiplexer coupled to said plurality of capacitive plate elements and adapted to selectively electrically couple said plates in one of a plurality of sensing range modalities; a capacitive sensing processing unit coupled to said sensor plate elements via said multiplexer so as to generate an electric field around said sensor plates and detect proximity of objects to said sensor plates as a function of capacitance between said sensor plates and said subject; and a shielding signal generation circuit coupled to said capacitive sensing system and to said multiplexer, said shielding generation circuit comprising a respective attenuating feedback circuit for each guard-sensor plate pair. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification