Object detection device with variable sensitivity electric field measurement circuit
First Claim
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1. An object detection device that detects whether an object is located between a frame and a movable object, which moves relative to the frame, the object detection device comprising:
- three or more first electrodes arranged on at least one of the frame and the movable object;
an electric field measurement unit connected to the first electrodes to measure the capacitance detected by any of the first electrodes and by any combination of the first electrodes;
a control circuit connected to the electric field measurement circuit to specify which of the first electrodes and which combinations of the first electrodes are to be used by the electric field measurement unit for measuring capacitance based on movement of the movable object, wherein changing the specified first electrodes used for measuring capacitance varies the sensitivity of the electric field measurement circuit; and
a position detecting circuit connected to the control circuit to detect the position of the movable object, wherein the control circuit specifies which of the first electrodes to use for measuring capacitance based on the position of the movable object.
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Abstract
Three or more electrodes are arranged on either a window frame or window glass of an automobile. An electric field measurement unit measures the capacitance between various combinations of the electrodes to detect whether an object is located between the window frame and window glass. A control circuit varies the sensitivity of the electric field measurement unit by switching amongst the electrodes used for capacitance measurement based on the movement and position of the window glass.
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Citations
14 Claims
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1. An object detection device that detects whether an object is located between a frame and a movable object, which moves relative to the frame, the object detection device comprising:
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three or more first electrodes arranged on at least one of the frame and the movable object; an electric field measurement unit connected to the first electrodes to measure the capacitance detected by any of the first electrodes and by any combination of the first electrodes; a control circuit connected to the electric field measurement circuit to specify which of the first electrodes and which combinations of the first electrodes are to be used by the electric field measurement unit for measuring capacitance based on movement of the movable object, wherein changing the specified first electrodes used for measuring capacitance varies the sensitivity of the electric field measurement circuit; and a position detecting circuit connected to the control circuit to detect the position of the movable object, wherein the control circuit specifies which of the first electrodes to use for measuring capacitance based on the position of the movable object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. An entrapment prevention device that prevents entrapment of an object between a frame and a movable object, which moves relative to the frame, the device comprising:
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a drive unit that moves the movable object relative to the frame; three or more electrodes arranged on at least one of the frame and the movable object; an electric field measurement unit connected to the three or more electrodes for determining capacitance measured by various combinations of the three or more electrodes; and a control circuit connected to the electric field measurement unit and the drive unit to control the drive unit based on the measured capacitances, and for selecting which ones of the three or more electrodes are used by the electric field measurement unit circuit based on a position of the movable object in order to vary the sensitivity of the electric field measurement unit, wherein the control circuit determines whether the object is a raindrop based on the capacitance measured by the electric field measurement unit and continues moving the movable object towards the frame when the detected object is a raindrop.
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14. An entrapment prevention device that prevents entrapment of an object between a frame and a movable object that moves relative to the frame, the device comprising:
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a drive unit that moves the movable object relative to the frame; a plurality of first electrodes located on the frame in spaced relation to one another; a plurality of second electrodes located on the movable object in spaced relation to one another; an electric field measurement unit connected to the pluralities of first and second electrodes for measuring capacitance detected by various combinations of the first and second electrodes; and a control circuit connected to the electric field measurement unit for specifying the various combinations of the first and second electrodes used for measuring capacitance, and connected to the drive unit for controlling movement of the movable object within the frame, wherein when the movable object is in a first detection zone the control circuit specifies measuring the capacitance using two electrodes of the first plurality of electrodes, when the movable object is in a second detection zone the control circuit specifies measuring the capacitance using two electrodes of the second plurality of electrodes, and when the movable object is in a third detection zone the control circuit specifies measuring the capacitance using at least one pair of electrodes wherein one electrode of the pair is from the plurality of first electrodes and the other electrode of the pair is from the plurality of second electrodes.
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Specification