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US 5,961,574 AGranted
Device for obtaining positional information
OwnerDavid Alan Woodfieldinventor
Life of this patent
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OwnerDavid Alan Woodfieldinventor
Estimating the term…
A device (10) for obtaining information relating to the relative positions of first and second members (11, 12), the first member (11) comprising at least three isolated electrically conducting parts (13-16), and the second member (12) being electrically conducting and adjacent to and capacitively coupled to the first member (11), the first and second members (11, 12) being relatively movable such that the proportions of each of the respective parts (13-16) of the first member (11) in overlapping relationship with the second member (12) may be varied, oscillator means (25) to provide a first waveform signal (26) to one of the parts (13-16) of the first member (11) and a second waveform signal (27) to another of the parts (13-16) of the first member (11), means (40) to analyze a signal arising in the capacitively coupled second member (12) to provide a device output signal (50) containing positional information and characterized in that a switch means (31) is provided whereby when the switch means (31) is in a first condition the first waveform signal (26) is selectively applied to a first part (16) of the first member (11) while the second waveform signal (27) is applied to a second part (15) of the first member (11) so that the device output signal (50) contains information relating to the relative positions of the first and second members (11, 12) in a first direction (33), and when the switch means (31) is in a second condition the first waveform signal (26) is applied to another part (14) of the first member (11) while the second waveform signal is applied to another one of the parts (15) of the first member so that the device output signal (50) contains information relating to the relative positions of the first (11) and second (12) members in a second direction (34).
A device for obtaining information relating to the relative positions of first and second members, the first member comprising at least three isolated electrically conducting parts, and the second member being electrically conducting and adjacent to and capacitively coupled to the first member, the first and second members being relatively movable such that the proportions of each of the respective parts of the first member in overlapping relationship with the second member may be varied, oscillator means to provide a first waveform signal to one of the parts of the first member and a second waveform signal to another of the parts of the first member, means to analyse a signal arising in the capacitively coupled second member to provide a device output signal containing positional information and characterised in that a switch means is provided whereby when the switch means is in a first condition the first waveform signal is selectively applied to a first part of the first member while the second waveform signal is applied to a second part of the first member so that the device output signal contains information relating to the relative positions of the first and second members in a first direction, and when the switch means is in a second condition the first waveform signal is applied to another part of the first member while the second waveform signal is applied to a different part of the first member so that the device output signal contains information relating to the relative positions of the first and second members in a second direction.
A method of obtaining information relating to the relative positions of first and second members utilising a device comprising a first member comprising at least three isolated electrically conducting parts, and a second member being electrically conducting and adjacent to and capacitively coupled to the first member, oscillator means to provide a first waveform signal to one of the parts of the first member and a second waveform signal to another of the parts of the first member, means to analyse a signal arising in the capacitively coupled second member to provide a device output signal characterised in that the method comprises relatively moving the first and second members such that the proportions of each of the respective parts of the first member in overlapping relationship with the second member are varied, operating a switch means in a first condition so that the first waveform signal is selectively applied to a first part of the first member while the second waveform signal is applied to a second part of the first member, analysing the signal arising in the capacitively coupled second member to provide a device output signal which contains information relating to the relative positions of the first and second members in a first direction, and operating the switch means in a second condition so that the first waveform signal is applied to another part of the first member while the second waveform signal is applied to a different one of the parts of the first member, analysing the signal arising in the capacitively coupled second member to provide a device output signal which contains information relating to the relative positions of the first and second members in a second direction.
Dependencies are inferred from the claim text.