US4488556A
Expired / Lapsed
US
⏱️ 0.0 years remaining
AC Mode operation of chemfet devices
Assignee: Ethicon Inc
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Filing: 1982-06-03
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Granted: 1984-12-18
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Expires: 2002-06-03
Abstract
Abstract A chemically sensitive field effect device has its chemically selective system exposed to the material being investigated. The device is driven by a time varying, typically sinusoidal, current source. A protected reference electrode is also in contact with the body under investigation, and is biased at a predetermined DC level relative to the chemically sensitive field effect device.
Inventors
- 👤 Nelson Ho
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:40
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/414; G01N27/4148
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
50 words
In combination, a chemically sensitive field effect transducer apparatus, means for coupling a sinusoidal drain-source potential to said transducer, and means for maintaining the gate of said transducer at a DC potential equal to the combination of a bias potential plus an electrochemically generated potential by a substance being sensed.
Claim 2
Dependent Claim
50 words
In combination, a chemically sensitive field effect transducer apparatus, means for coupling a sinusoidal drain-source potential to said transducer, and means for maintaining the gate of said transducer at a DC potential equal to the combination of a bias potential plus an electrochemically generated potential by a substance being sensed.
Claim 3
Dependent Claim
23 words
Apparatus as described in claim 1 and further comprising a reference electrode maintained at a predetermined DC bias relatve to the source electrode.
Claim 4
Dependent Claim
26 words
Apparatus as described in claim 2 wherein said means for generating generates a waveform having a frequency in the range between 10 Hz. and 1 MHz.
Claim 5
Dependent Claim
26 words
Apparatus as described in claim 3 wherein said means for generating generates a waveform having a frequency in the range between 100 kHz. and 200 kHz.
Claim 6
Dependent Claim
108 words
Apparatus for sensing the presence of a specified substance in a subject comprising: (a) a chemically sensitive field effect device having respective drain and source connections, a drain to source conduction path, and a chemically selective system overlying said path and modulating current therein in response to presence of said substance in said subject; (b) a reference electrode coupled to said subject; (c) means for generating and for coupling to said conduction path a sinusoidal time variant signal; and (d) means, coupled between said source and said reference electrode, for establishing a gate potential consisting of a bias potential plus the potential generated electrochemically by said specified substance.
Claim 7
Dependent Claim
108 words
Apparatus for sensing the presence of a specified substance in a subject comprising: (a) a chemically sensitive field effect device having respective drain and source connections, a drain to source conduction path, and a chemically selective system overlying said path and modulating current therein in response to presence of said substance in said subject; (b) a reference electrode coupled to said subject; (c) means for generating and for coupling to said conduction path a sinusoidal time variant signal; and (d) means, coupled between said source and said reference electrode, for establishing a gate potential consisting of a bias potential plus the potential generated electrochemically by said specified substance.
Claim 8
Dependent Claim
28 words
Apparatus as described in claim 5 wherein said means for generating comprises means for generating a substantially sinusoidal current waveform having a mean value of approximately zero volts.
Claim 9
Dependent Claim
26 words
Apparatus as described in claim 6 wherein said means for generating generates a waveform having a frequency in the range between 10 Hz. and 1 MHz.
Claim 10
Dependent Claim
26 words
Apparatus as described in claim 6 wherein said means for generating generates a waveform having a frequency in the range between 100 kHz. and 200 kHz.
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) | 1987-12-18 | 1988-06-18 | 1988-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-18 | 1992-06-18 | 1992-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-18 | 1996-06-18 | 1996-12-18 | $7700.00 | Window Closed / Lapsed |