US3732369A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coordinate digitizer system
Assignee: Welland Investment Trust
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Filing: 1971-04-05
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Granted: 1973-05-08
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Expires: 1991-04-05
Abstract
Abstract A coordinate digitizer employs a stylus whose position on a platen is converted into digitized coordinates by utilizing the signals capacitively coupled to the stylus. The platen has a coarse grid formed by two crossed sets of parallel wires regularly spaced along the coordinate axes. The platen also has a fine grid of crossed sets of parallel wires spaced more closely along the coordinate axes than the coarse grid wires. The wires in a fine grid set are constituted by four groups of wires. To digitize the stylus position along one coordinate axis, all the wires of a group are electrically pulsed together, each group being pulsed in turn. The wires of the coarse grid are then pulsed, one at a time, in sequence. The signals detected by the stylus from the pulsing of the fine wires are used to establish a ''''fine'''' digitized position that periodically recurs along the coordinate axis. The signals detected by the stylus from the pulsing of the coarse wires are used to establish a ''''coarse'''' digitized position that uniquely fixes the fine position on the coordinate axis. The system then scans the wire of the other coordinate axis in the same manner to digitize the position of the stylus on that axis. The system alternately scans the coordinate axes to repetitively digitize the position of the stylus with sufficient rapidity to track the movements of the stylus.
Inventors
- 👤 W Cotter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 22:19
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/044; G06F3/0441
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
182 words
A system for digitizing the position of a stylus on a coordinate axis, the system comprising a platen having a coarse set of parallel wires spaced along the coordinate axis, the stylus having an electrical conductor providinG capacitive coupling to the coarse set of wires, means associated with the stylus for causing differentiation of the stylus output signals, scan pulse means for electrically pulsing in sequence wires of the coarse set, the pulses being contiguous whereby the trailing edge of one pulse is concurrent with the leading edge of the next succeeding pulse in the sequence, a counter coacting with the scan pulse means to cause the count in the counter to identify the wire being pulsed, a crossover detector, the differentiated output signals of the stylus being coupled to the input of the crossover detector, the crossover detector emitting an output signal upon detecting a change in polarity of the differentiated output signals from the stylus, and means coupled to the output of the detector for indicating the count in the counter upon emission of an output signal from the detector.
Claim 2
Independent Claim
182 words
A system for digitizing the position of a stylus on a coordinate axis, the system comprising a platen having a coarse set of parallel wires spaced along the coordinate axis, the stylus having an electrical conductor providinG capacitive coupling to the coarse set of wires, means associated with the stylus for causing differentiation of the stylus output signals, scan pulse means for electrically pulsing in sequence wires of the coarse set, the pulses being contiguous whereby the trailing edge of one pulse is concurrent with the leading edge of the next succeeding pulse in the sequence, a counter coacting with the scan pulse means to cause the count in the counter to identify the wire being pulsed, a crossover detector, the differentiated output signals of the stylus being coupled to the input of the crossover detector, the crossover detector emitting an output signal upon detecting a change in polarity of the differentiated output signals from the stylus, and means coupled to the output of the detector for indicating the count in the counter upon emission of an output signal from the detector.
Claim 3
Dependent Claim
150 words
A system, according to claim 1, for digitizing the position of a stylus on a second coordinate axis, wherein the platen has a second coarse set of parallel wires spaced along the second coordinate axis, and the system further includes additional scan pulse means for electrically pulsing in sequence wires of the second coarse set, a second counter coacting with the additional scan pulse means to cause the count in the second counter to identify the wire being pulsed in the second coarse set, means for alternately scanning the first and second coarse sets of wires, and means operative during the scanning of the sets of wires along the first coordinate axis for causing the counter for the second coordinate axis to alter its count by a predetermined amount whereby the succeeding scan along the second coordinate axis commences at the location corresponding to the altered count of the counter.
Claim 4
Dependent Claim
167 words
A system according to claim 1 for digitizing the position of a stylus on a coordinate axis, the system further comprising a fine set of parallel wires on the platen, the fine set being more closely spaced along the coordinate axis than the wires of the coarse set, the wires of the fine set constituting groups, the wires of each group being interleaved with the wires of the other groups whereby the wires of the groups occur repetitively in the same successive order along the coordinate axis, pulse means for electrically pulsing all the wires of a group together, the pulse means causing each group to be separately pulsed in its turn, and signal processing means coupled to the output of the stylus, the signal processing means being responsive to the amplitude characteristics of the signals capacitively coupled to the stylus from the groups of wires in the fine set, and the signal processing means providing digital signals representing divisions of the internal between coarse grid lines.
Claim 5
Dependent Claim
115 words
A system according to claim 3 for digitizing the position of a stylus on a coordinate axis, wherein the signal processing means comprises sample and hold means responsive to signal amplitude for sampling the output of the stylus concurrently with the pulsing of each group of wires in the fine set and storing the sampled signals, and combining means responsive to the amplitude of the stored sampled signals for providing first and second basic signals, each basic signal varying periodically as the stylus is moved along the coordinate axis, the basic signals being out of phase whereby the ratio of one basic signal to the other is unvarying for any stationary position of the stylus.
Claim 6
Dependent Claim
47 words
A system, according to claim 4, for digitizing the position of a stylus on a coordinate axis, wherein the signal processing means further comprises means responsive to the first and second basic signals for providing digital output signals representing divisions of the interval between coarse grid wires.
Claim 7
Dependent Claim
61 words
A system according to claim 5, for digitizing the position of a stylus on a coordinate axis, wherein the system further comprises carry circuIt means for causing the count in the counter to change concurrently with a change in the digital output signal of the signal processing means which represents the next finer bit to the coarse bit in the counter.
Claim 8
Dependent Claim
169 words
A system according to claim 6, for digitizing the position of a stylus, wherein the platen has second coarse and fine sets of parallel wires spaced along a second coordinate axis, and the system further includes additional scan pulse means for electrically pulsing in sequence wires of the second coarse set, additional pulse means for electrically pulsing the second fine set of wires in groups, a second counter coacting with the additional scan pulse means to cause the count in the second counter to identify the wire being pulsed in the second coarse set, means for alternately scanning the first and second sets of parallel wires to alternately obtain a digitized coordinate for each axis, and means operative during the scanning of the sets of wires along the first coordinate axis for causing the counter for the second coordinate axis to alter its count by a predetermined amount whereby the succeeding scan along the second coordinate axis commences at the location corresponding to the altered count of the counter.
Claim 9
Independent Claim
191 words
A system for digitizing the position of a stylus on a coordinate axis, the system comprising a platen having a coarse set of parallel wires spaced along the coordinate axis, the stylus having an electrical conductor providing capacitive coupling to the coarse set of wires, scan pulse means for electrically pulsing in sequence wires of the coarse set, a counter coacting with the scan pulse means to cause the count in the counter to identify the wire being pulsed, sample and hold means coupled to the output of the stylus, the sample and hold means causing the output of the stylus to be sampled concurrently with the pulsing of the wires of the coarse set, a differentiator, the input of the differentiator being coupled to the output of the sample and hold means, a crossover detector having its input fed by the output of the differentiator, the crossover detector emitting an output signal upon detecting a change in polarity of the signals emitted by the differentiator, and means coupled to the output of the detector for indicating the count in the counter upon emission of an output signal from the detector.
Claim 10
Independent Claim
191 words
A system for digitizing the position of a stylus on a coordinate axis, the system comprising a platen having a coarse set of parallel wires spaced along the coordinate axis, the stylus having an electrical conductor providing capacitive coupling to the coarse set of wires, scan pulse means for electrically pulsing in sequence wires of the coarse set, a counter coacting with the scan pulse means to cause the count in the counter to identify the wire being pulsed, sample and hold means coupled to the output of the stylus, the sample and hold means causing the output of the stylus to be sampled concurrently with the pulsing of the wires of the coarse set, a differentiator, the input of the differentiator being coupled to the output of the sample and hold means, a crossover detector having its input fed by the output of the differentiator, the crossover detector emitting an output signal upon detecting a change in polarity of the signals emitted by the differentiator, and means coupled to the output of the detector for indicating the count in the counter upon emission of an output signal from the detector.
Claim 11
Dependent Claim
153 words
The system according to claim 8 wherein the platen has a second coarse set of parallel wires spaced along a second coordinate axis, the system being arranged to digitize the position of the stylus on the second coordinate axis, the system further including additional scan pulse means for electrically pulsing in sequence wires of the second coarse set, a second counter coacting with the additional scan pulse means to cause the count in the second counter to identify the wire being pulsed in the second coarse set, means for alternately scanning the first and second coarse sets of wires, and means operative during the scanning of the sets of wires along the first coordinate axis for causing the counter for the second coordinate axis to alter its count by a predetermined amount whereby the succeeding scan along the second coordinate axis commences at the location corresponding to the altered count of the counter.
Claim 12
Dependent Claim
167 words
The system according to claim 9 for digitizing the position of a stylus on a coordinate axis, the system further comprising a fine set of parallel wires on the platen, the fine set being more closely spaced along the coordinate axis than the wires of the coarse set, the wires of the fine set constituting groups, the wires of each group being interleaved with the wires of the other groups whereby the wires of the groups occur repetitively in the same successive order along the coordinate axis, pulse means for electrically pulsing all the wires of a group together, the pulse means causing each group to be separately pulsEd in its turn, and signal processing means coupled to the output of the stylus, the signal processing means being responsive to the amplitude characteristics of the signals capacitively coupled to the stylus from the groups of wires in the fine set, and the signal processing means providing digital signals representing divisions of the interval between coarse grid lines.
Claim 13
Dependent Claim
105 words
The system according to claim 10 wherein the signal processing means comprises sample and hold means responsive to signal amplitude for sampling the output of the stylus concurrently with the pulsing of each group of wires in the fine set and storing the sampled signals, and combining means responsive to the amplitude of the stored sampled signals for providing first and second basic signals, each basic signal varying periodically as the stylus is moved along the coordinate axis, and the basic signals being out of phase whereby the ratio of one basic signal to the other is unvarying for any stationary position of the stylus.
Claim 14
Dependent Claim
37 words
The system according to claim 11 wherein the signal processing means further comprises means responsive to the first and second basic signals for providing digital output signals representing the divisions of the interval between coarse grid wires.
Claim 15
Dependent Claim
162 words
The system according to claim 12 wherein the platen has second coarse and fine sets of parallel wires spaced along a second coordinate axis, and the system further includes additional scan pulse means for electrically pulsing in sequence wires of the second coarse set, additional pulse means for electrically pulsing the second fine set of wires in groups, a second counter coacting with the additional scan pulse means to cause the count in the second counter to identify the wire being pulsed in the second coarse set, means for alternately scanning the first and second sets of parallel wires to alternately obtain a digitized coordinate for each axis, and means operative during the scanning of the sets of wires along the first coordinate axis for causing the counter for the second coordinate axis to alter its count by a predetermined amount whereby the succeeding scan along the second coordinate axis commences at the location corresponding to the altered count of the counter.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-05-07 | 1976-11-06 | 1977-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-07 | 1980-11-06 | 1981-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-07 | 1984-11-06 | 1985-05-08 | $7700.00 | Window Closed / Lapsed |