Patent US3670103A successfully refreshed from Google Patents.
US3670103A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Graphical input tablet
Assignee: SHINTRON CO Inc
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Filing: 1971-04-28
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Granted: 1972-06-13
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Expires: 1991-04-28
Abstract
Abstract An a-c potential field is established on an electrographic tablet. A stylus that may be used to write upon the tablet comprises a capacitive pickup to provide a potential representative of the stylus position. The potential field is alternately switched at a rapid rate between vertical equipotentials and horizontal equipotentials in synchronism with output analog switches coupled to the stylus to provide an X analog signal output and a Y analog signal output representative of the horizontal and vertical coordinates, respectively, of the stylus tip above the tablet.
Inventors
- 👤 Larry K Baxter
- 👤 Shintaro Asano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 14:12
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/045; G06F3/044; G06F3/0441
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
109 words
In an electrographic apparatus having a conductive tablet, means for selectively establishing first and second orthogonal electric fields in said conductive sheet during mutually exclusive time intervals, and probe means for coupling a signal on a point of said tablet to first and second terminals, phase controlled detection electronics comprising, a difference amplifier means having a pair of input terminals coupled to said probe means, a multiplier having one input coupled from said difference amplifier, an output amplifier coupled from the output of said multiplier, and a phase controlled square wave generator coupled from said output amplifier and having an output that couples to another input of said multiplier.
Claim 2
Dependent Claim
109 words
In an electrographic apparatus having a conductive tablet, means for selectively establishing first and second orthogonal electric fields in said conductive sheet during mutually exclusive time intervals, and probe means for coupling a signal on a point of said tablet to first and second terminals, phase controlled detection electronics comprising, a difference amplifier means having a pair of input terminals coupled to said probe means, a multiplier having one input coupled from said difference amplifier, an output amplifier coupled from the output of said multiplier, and a phase controlled square wave generator coupled from said output amplifier and having an output that couples to another input of said multiplier.
References Cited (Backward Citations)
US3530241A
Cited
US3591718A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-06-13 | 1975-12-13 | 1976-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-13 | 1979-12-13 | 1980-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-13 | 1983-12-13 | 1984-06-13 | $7700.00 | Window Closed / Lapsed |