US4929934A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pressure-sensitive input apparatus
Assignee: Oki Electric Industry Co Ltd
•
Filing: 1988-09-22
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Granted: 1990-05-29
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Expires: 2008-09-22
Abstract
Abstract In a pressure-sensitive input apparatus comprising an X-coordinate detection resistive member connected to mutually parallel vertical electrodes and a Y-coordinate detection resistive member connected to mutually parallel horizontal electrodes, for detecting the position of a point depressed by a stylus or the like, by detecting changes in the resistance values of these resistive members, switches are provided for on-off control of the current flowing into or out of both ends of the X-coordinate detection resistive member and the Y-coordinate detection resistive member, and a voltage detection circuit detects the voltage between the X-coordinate detection resistive member and the Y-coordinate detection resistive member. Multiple inputs can be detected according to the results obtained from the voltage detection circuit when the currents are switched by the switches.
Inventors
- 👤 Kenichi Ueda
- 👤 Kouji Hattori
- 👤 Akihiko Terada
- 👤 Kazuyoshi Inohara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:06
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/03; G06F3/041; G06F3/045
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
202 words
A pressure-sensitive input apparatus comprising: vertical electrodes which are parallel with each other; horizontal electrodes which are parallel with each other, intersect said vertical electrodes and are separated from the vertical electrodes; the electrical resistance between said vertical electrodes and said horizontal electrodes being reduced at a location where a pressure is applied; an X-coordinate detection resistive member connected to the vertical electrodes; a Y-coordinate detection resistive member connected to the horizontal electrodes; current supply means for supplying an electric current through said vertical electrodes, said horizontal electrodes, said X-coordinate detection resistive member and said Y-coordinate detection resistive member; coordinate calculating means for detecting currents through said X-coordinate detection resistive member and said Y-coordinate detection resistive member and calculating the positional coordinate at which a pressure is applied; switching means for on-off control of the current flowing through both ends of the X-coordinate detection resistive member and the Y-coordinate detection resistive member; voltage detection means for detecting the voltage between the X-coordinate detection resistive member and the Y-coordinate detection resistive member; judgment means responsive to the voltage detection means for detecting multiple input according to the results obtained from the voltage detection means when the currents are switched by the switching means.
Claim 2
Dependent Claim
202 words
A pressure-sensitive input apparatus comprising: vertical electrodes which are parallel with each other; horizontal electrodes which are parallel with each other, intersect said vertical electrodes and are separated from the vertical electrodes; the electrical resistance between said vertical electrodes and said horizontal electrodes being reduced at a location where a pressure is applied; an X-coordinate detection resistive member connected to the vertical electrodes; a Y-coordinate detection resistive member connected to the horizontal electrodes; current supply means for supplying an electric current through said vertical electrodes, said horizontal electrodes, said X-coordinate detection resistive member and said Y-coordinate detection resistive member; coordinate calculating means for detecting currents through said X-coordinate detection resistive member and said Y-coordinate detection resistive member and calculating the positional coordinate at which a pressure is applied; switching means for on-off control of the current flowing through both ends of the X-coordinate detection resistive member and the Y-coordinate detection resistive member; voltage detection means for detecting the voltage between the X-coordinate detection resistive member and the Y-coordinate detection resistive member; judgment means responsive to the voltage detection means for detecting multiple input according to the results obtained from the voltage detection means when the currents are switched by the switching means.
Claim 3
Dependent Claim
32 words
An apparatus according to claim 1, wherein said judgment means detects the multiple input according to the results obtained from the voltage detection means when the switching means are in respective states.
Claim 4
Dependent Claim
33 words
An apparatus according to claim 2, further comprising control means for controlling said switching means, wherein said judgment means is responsive to the control means to determine the states of the switching means.
Claim 5
Dependent Claim
45 words
An apparatus according to claim 1, wherein said current supply means has a first output terminal connected to first and second ends of said X-coordinate detection resistive member, and a second output terminal connected to first and second ends of said Y-coordinate detection resistive member.
Claim 6
Dependent Claim
23 words
An apparatus according to claim 4, wherein said X-coordinate detection resistive member and said Y-coordinate detection resistive member have a uniform lengthwise resistivity.
Claim 7
Dependent Claim
108 words
An apparatus according to claim 5, wherein said switching means comprises: a first switch interposed between said first output terminal of said current supply means and said first end of said X-coordinate detection resistive member, a second switch interposed between said first output terminal of said current supply means and said second end of said X-coordinate detection resistive member, a third switch interposed between said second output terminal of said current supply means and said first end of said Y-coordinate detection resistive member, and a fourth switch interposed between said second output terminal of said current supply means and said second end of said Y-coordinate detection resistive member.
Claim 8
Dependent Claim
191 words
An apparatus according to claim 6, wherein said voltage detection means is connected to detect the voltage across said first output terminal and said second output terminal of said current supply means, and said judgment means makes said judgment in accordance with whether or not the following relationship holds: |(v.sub.1 +v.sub.2)-(v.sub.3 +v.sub.4)|<e where v 1 is the voltage detected by said voltage detection means when said first switch is on, said second switch is off, said third switch is on and said fourth switch is off, v 2 is the voltage detected by said voltage detection means when said first switch is off, said second switch is on, said third switch is off and said fourth switch is on, v 3 is the voltage detected by said voltage detection means when said first switch is on, said second switch is off, said third switch is off and said fourth switch is on, v 4 is the voltage detected by said voltage detection means when said first switch is off, said second switch is on, said third switch is on and said fourth switch is off, and e is a predetermined value.
Claim 9
Dependent Claim
37 words
An apparatus according to claim 7, wherein the pitch of the electrode is so small that the probability of erroneous input at multiple locations where either the X-coordinate values or the Y-coordinate values are identical is negligible.
Claim 10
Dependent Claim
137 words
An apparatus according to claim 7, wherein said coordinate calculating means determines the X-coordinate x and the Y-coordinate by performing the following calculation: x=L.sub.x ·i.sub.2 /I.sub.0 y=L.sub.y ·i.sub.4 /I.sub.0 where L x is the length of the effective input area in the direction of the horizontal electrodes, L y is the length of the effective input area in the direction of the vertical electrodes, I o is the current value of the current supply means when said first, second, third and fourth switches are all on, i 2 is the current through one end of the X-coordinate detection resistive member when said first, second, third and fourth switches are all on, and i 4 is the current through one end of the Y-coordinate detection resistive member when said first, second, third and fourth switches are all on.
Claim 11
Dependent Claim
16 words
An apparatus according to claim 9, wherein said current supply means is a constant-current supply means.
Claim 12
Dependent Claim
26 words
An apparatus according to claim 1, wherein said vertical electrodes and said horizontal electrodes are separated from each other by a pressure-sensitive sheet or air gap.
References Cited (Backward Citations)
JPS5734543A
Cited
US4819194A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-05-28 | 1993-11-27 | 1994-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-05-28 | 1997-11-27 | 1998-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-05-28 | 2001-11-27 | 2002-05-29 | $7700.00 | Window Closed / Lapsed |