Patent US5914701A successfully refreshed from Google Patents.
US5914701A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Non-contact system for sensing and signalling by externally induced intra-body currents
Assignee: Massachusetts Institute of Technology
•
Filing: 1997-08-06
•
Granted: 1999-06-22
•
Expires: 2017-08-06
Abstract
Abstract A wireless system includes one or more transmitters and one or more remote receivers that are respectively coupled through one or more users and room ground. The transmitters each produce low-frequency, low power signals that, through capacitive coupling, pass as displacement currents into and from the body of the user, which acts as a conductive node. A receiver that couples capacitively to the user responds to the displacement currents and reproduces the signals. The transmitter includes a signal generator and a pair of electrodes. The signal generator produces modulated signals that vary the voltage between the electrodes, a first one of which is closely coupled capacitively to the user's body such that the "quasi-electrostatic" field resulting from the electrode potential causes a displacement current to pass to the user's body. The second electrode is oriented so that its coupling to the room ground is stronger than that of the first electrode, such that room ground acts as a return path for the current from the receiver. The signal generator may modulate the information to be transmitted using, for example, a pseudorandom code, to produce spread spectrum signals. This increases noise immunity and allows multiple transmitters, each using a different modulation code, to operate at the same time. The receivers each include a detector/demodulator that acquires and tracks the signals from the one or more transmitters.
Inventors
- 👤 Neil Gersheneld
- 👤 Thomas Zimmerman
- 👤 David Allport
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:45
CPC Classifications
G; G06; G06F; G06F3/00; G06F3/01; G06F3/017; H; H04; H04B; H04B5/00; H04B5/20; H04B5/22; G06F3/03; G06F3/033; G06F3/0346; G06F3/041; G06F3/0416; G06F3/04162; G06F3/044; G06K; G06K19/00; G06K19/04; G06K19/041; G06K19/06; G06K19/067; G06K19/07; G06K19/077; G06K19/07749; G06K19/07758; G06K19/07773; G06K19/07788; G06K7/00; G06K7/10; G06K7/10009; G06K7/10316; G06K7/10326; H04B13/00; H04B13/005; H04B5/40; H04B5/48; G06F3/046; Y; Y02; Y02D; Y02D30/00; Y02D30/70
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
88 words
A wireless communication system including: A. a transmitter for producing low frequency signals that include data, the transmitter being capacitively coupled to a user and to ground, the transmitter passing to the user a current that is associated with the low frequency signals; and B. a receiver that is displaced from the user and is coupled to ground for receiving when capacitively coupled to the user a current that is associated with the signals produced by the transmitter, the receiver reproducing the transmitted signals and recovering the data.
Claim 2
Dependent Claim
88 words
A wireless communication system including: A. a transmitter for producing low frequency signals that include data, the transmitter being capacitively coupled to a user and to ground, the transmitter passing to the user a current that is associated with the low frequency signals; and B. a receiver that is displaced from the user and is coupled to ground for receiving when capacitively coupled to the user a current that is associated with the signals produced by the transmitter, the receiver reproducing the transmitted signals and recovering the data.
Claim 3
Dependent Claim
46 words
The wireless communication system of claim 1, wherein the transmitter includes: i. a pair of electrodes; and ii. a signal generator connected between the electrodes, the signal generator generating the low frequency signals that result in an associated displacement current between the electrodes and the user.
Claim 4
Dependent Claim
44 words
The wireless communication system of claim 2, wherein the receiver includes: i. a pair of electrodes; and ii. a signal detector connected between the electrodes, the signal detector reproducing the low frequency signals from a displacement current developed between the electrodes and the user.
Claim 5
Dependent Claim
43 words
The wireless communication system of claim 1 wherein the system further includes a. a plurality of receivers; and b. a processor for determining from the signals reproduced by the receivers the position of the user relative to one or more of the receivers.
Claim 6
Dependent Claim
48 words
The wireless communication system of claim 4 wherein: the receivers are mounted on the periphery of a computer screen; and the processor moves a cursor to a position on the screen that is associated with the position of the user relative to one or more of the receivers.
Claim 7
Dependent Claim
26 words
The wireless communication system of claim 2 wherein the transmitter further includes a signal modulator for spread spectrum modulating the signals with a predetermined pseudorandom code.
Claim 8
Dependent Claim
60 words
The wireless communication system of claim 6 wherein the system further includes a plurality of transmitters, each of the transmitters being associated with a predetermined code that differs from the codes associated with the other transmitters in the system, the receiver using the codes to distinguish between the signals passed from each of the transmitters in the plurality of transmitters.
Claim 9
Dependent Claim
44 words
The wireless communication system of claim 7 wherein each of the transmitters in the plurality of transmitters is capacitively coupled to a different user, and the receiver receives signals respectively from the individual transmitters when the receiver is capacitively coupled to the individual transmitters.
Claim 10
Dependent Claim
36 words
The wireless communication system of claim 8 wherein the system further includes: a. a plurality of receivers; and b. a processor for determining from the signals reproduced by the receivers the relative positions of the users.
Claim 11
Dependent Claim
53 words
The wireless communication system of claim 9 wherein: the receivers are mounted on the periphery of a computer screen; and the processor moves one or more objects to positions on the screen that are associated with the positions of one or more of the users relative to one or more of the receivers.
Claim 12
Dependent Claim
147 words
A computer system including: A. a screen for displaying on-screen objects; B. a keyboard for data entry to the system; C. a transmitter for producing low frequency signals, the transmitter being capacitively coupled to a user to pass to the user a current that is associated with the low frequency signals; D. a plurality of receivers mounted on the periphery of the screen, each of the receivers in the plurality receiving from the user, through capacitive coupling to the user, a current that is associated with the signals produced by the transmitter, the receivers determining the position of the closest extremity of the user's body relative to one or more of the receivers; and E. a processor for controlling the screen display, the processor directing the screen to display the objects in positions that correspond to the position of the user's extremity as determined by the receivers.
Claim 13
Dependent Claim
147 words
A computer system including: A. a screen for displaying on-screen objects; B. a keyboard for data entry to the system; C. a transmitter for producing low frequency signals, the transmitter being capacitively coupled to a user to pass to the user a current that is associated with the low frequency signals; D. a plurality of receivers mounted on the periphery of the screen, each of the receivers in the plurality receiving from the user, through capacitive coupling to the user, a current that is associated with the signals produced by the transmitter, the receivers determining the position of the closest extremity of the user's body relative to one or more of the receivers; and E. a processor for controlling the screen display, the processor directing the screen to display the objects in positions that correspond to the position of the user's extremity as determined by the receivers.
Claim 14
Dependent Claim
14 words
The computer system of claim 11 wherein the transmitter is incorporated into the keyboard.
Claim 15
Dependent Claim
69 words
The computer system of claim 11 further including a receiver that is mounted on the keyboard, the receiver determining, based on the strength of the received signals if the user is selecting the information that is displayed below the cursor, the system determining that the user is selecting the information if the strength of the signals received by the receiver mounted on the keyboard is above a predetermined threshold.
Claim 16
Dependent Claim
133 words
A wireless communication system including: A. a plurality of transmitters for producing low frequency signals, the transmitters being capacitively coupled to one or more users and to ground and, respectively, including a pair of electrodes and connected between the electrodes a signal generator that generates low frequency signals, each transmitter passing to the associated user a current that is associated with the low frequency signals; and B. a plurality of receivers coupled to ground for receiving, respectively, from the one or more users to which they capacitively couple one or more currents associated with the signals produced by the transmitters, the receivers reproducing the transmitted signals; and C. a processor for determining from the signals reproduced by the receivers the respective positions of the users relative to one or more of the receivers.
Claim 17
Dependent Claim
133 words
A wireless communication system including: A. a plurality of transmitters for producing low frequency signals, the transmitters being capacitively coupled to one or more users and to ground and, respectively, including a pair of electrodes and connected between the electrodes a signal generator that generates low frequency signals, each transmitter passing to the associated user a current that is associated with the low frequency signals; and B. a plurality of receivers coupled to ground for receiving, respectively, from the one or more users to which they capacitively couple one or more currents associated with the signals produced by the transmitters, the receivers reproducing the transmitted signals; and C. a processor for determining from the signals reproduced by the receivers the respective positions of the users relative to one or more of the receivers.
Claim 18
Dependent Claim
38 words
The wireless communication system of claim 14 wherein: i. the transmitters each, respectively, transmit signals associated with a different predetermined code; and ii. the receivers distinguish between the signals produced by the individual transmitters based on the codes.
Claim 19
Dependent Claim
27 words
The wireless communication system of claim 14 wherein the receivers distinguish between the signals produced by the individual transmitters based on the times the signals are transmitted.
Claim 20
Dependent Claim
36 words
The wireless communication system of claim 14 wherein: i. the transmitters each, respectively, transmit signals at different predetermined frequencies; and ii. the receivers distinguish between the signals produced by the individual transmitters based on the frequencies.
Claim 21
Independent Claim
220 words
A system including: A. a screen for displaying one or more on-screen objects including a cursor; B. a keyboard for data entry to the system; C. a transmitter for producing low frequency signals, the transmitter being capacitively coupled to a user to pass to the user a current that is associated with the low frequency signals; D. a plurality of receivers mounted on the periphery of the screen, each of the receivers in the plurality receiving from the user, through capacitive coupling to the user, a current that is associated with the signals produced by the transmitter, the receivers determining the position of the closest extremity of the user's body relative to one or more of the receivers; E. a selection receiver mounted on the system for determining, based on the strength of the received signals, if the user is selecting the information that is displayed below the cursor, the system determining that the user is selecting the information if the strength of the signals received by the selection receiver is above a predetermined threshold; and F. a processor for controlling the screen display, the processor directing the screen to display one or more of the objects in positions that correspond to the position of the user's extremity as determined by one or more of the plurality of the receivers.
Claim 22
Independent Claim
220 words
A system including: A. a screen for displaying one or more on-screen objects including a cursor; B. a keyboard for data entry to the system; C. a transmitter for producing low frequency signals, the transmitter being capacitively coupled to a user to pass to the user a current that is associated with the low frequency signals; D. a plurality of receivers mounted on the periphery of the screen, each of the receivers in the plurality receiving from the user, through capacitive coupling to the user, a current that is associated with the signals produced by the transmitter, the receivers determining the position of the closest extremity of the user's body relative to one or more of the receivers; E. a selection receiver mounted on the system for determining, based on the strength of the received signals, if the user is selecting the information that is displayed below the cursor, the system determining that the user is selecting the information if the strength of the signals received by the selection receiver is above a predetermined threshold; and F. a processor for controlling the screen display, the processor directing the screen to display one or more of the objects in positions that correspond to the position of the user's extremity as determined by one or more of the plurality of the receivers.
Claim 23
Dependent Claim
14 words
The system of claim 18 wherein the selection receiver is mounted on the keyboard.
Claim 24
Dependent Claim
15 words
The system of claim 19 wherein the system further includes a plurality of selection receivers.
Claim 25
Dependent Claim
15 words
The wireless communication system of claim 1 wherein the receiver is mounted on an object.
Claim 26
Dependent Claim
15 words
The wireless communication system of claim 1 wherein the receiver is coupled to another user.
Claim 27
Dependent Claim
66 words
The wireless communication system of claim 1 wherein the system further includes: a. a plurality of transmitters that are capacitively coupled to one or more users; b. a plurality of receivers that are displaced from the users; and c. a processor for determining from the signals reproduced by the receivers the positions of the one or more users relative to one or more of the receivers.
Claim 28
Dependent Claim
21 words
The wireless communication system of claim 23 wherein: i. the transmitters also receive signals; and ii. the receivers also transmit signals.
Claim 29
Dependent Claim
21 words
The wireless communication system of claim 1 wherein: i. the transmitter also receives signals; and ii. the receiver also transmits signals.
References Cited (Backward Citations)
US4688037A
Cited
GB2129176A
Cited
JPS60250731A
Cited
JPS6146639A
Cited
US4903012A
Cited
US4988981A
Cited
US4988981B1
Cited
US4918737A
Cited
US5204672A
Cited
US5367315A
Cited
US5488204A
Cited
US5380983A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-06-21 | 2002-12-21 | 2003-06-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-06-21 | 2006-12-21 | 2007-06-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-06-21 | 2010-12-21 | 2011-06-22 | $7700.00 | Window Closed / Lapsed |