US4844076A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ingestible size continuously transmitting temperature monitoring pill
Assignee: Johns Hopkins University
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Filing: 1988-08-26
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Granted: 1989-07-04
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Expires: 2008-08-26
Abstract
Abstract A temperature responsive transmitter is disclosed. The transmitter utilizes a unique circuit design that allows encapsulation in an ingestible size capsule. The inventive circuit design uses a one transistor inverting amplifier with a tank circuit forming the link between the transistor's collector and the battery. The tank circuit is tuned to provide a lagging capacitive load which causes the inverting amplifier to oscillate. The tank circuit contains a coil inductor that emits a near field magnetic communications field containing temperature information. The ingestible size temperature pill can be configured in a rechargeable embodiment. In this embodiment the pill uses the inductive coil in the tank circuit as the magnetic pickup to charge a rechargeable nickel cadmium battery.
Inventors
- 👤 Jeffery C. Lesho
- 👤 Arthur F. Hogrefe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:04
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/68; A61B5/6846; A61B5/6847; A61B5/6861; A01; A01K; A01K11/00; A01K11/006; A01K11/007; A61B5/0002; A61B5/0004; A61B5/0008; A61B5/07; A61B5/073; G; G01; G01K; G01K1/00; G01K1/02; G01K1/024; G01K7/00; G01K7/32; A61B18/00; A61B18/04; A61B18/12; A61B18/14; A61B2018/1405; A61B2018/1435; A61B2560/00; A61B2560/02; A61B2560/0204; A61B2560/0214; A61B2560/0219; Y; Y10; Y10S; Y10S128/00; Y10S128/903
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
182 words
A miniaturized temperature responsive transmitter comprising: a battery providing a voltage V b ; reed-switch means adapted to be controlled by a magnet to disconnect the battery during storage; a one-transistor inverting amplifier having an input and output and operably biased to said battery; a temperature-sensitive crystal operably coupled between said input and output of said inverting amplifier and having a natural frequency dependent on local temperature; a tank circuit having an inductor and a capacitor, operably coupled between said output of said inverting amplifier and said battery and tuned to a frequency lower than the natural frequency of said temperature-sensitive crystal for both providing a lagging phase shift at the output of said inverting amplifier and for emitting a near field magnetic signal from said inductor, wherein the frequency of said near field magnetic signal is dependent upon the frequency of the temperature sensitive crystal which is temperature dependent, and wherein said inverting amplifier acts as a switch causing said capacitor to charge and discharge through said inductor, thereby allowing the tank circuit to operate at 2 V b peak-to-peak volts.
Claim 2
Dependent Claim
182 words
A miniaturized temperature responsive transmitter comprising: a battery providing a voltage V b ; reed-switch means adapted to be controlled by a magnet to disconnect the battery during storage; a one-transistor inverting amplifier having an input and output and operably biased to said battery; a temperature-sensitive crystal operably coupled between said input and output of said inverting amplifier and having a natural frequency dependent on local temperature; a tank circuit having an inductor and a capacitor, operably coupled between said output of said inverting amplifier and said battery and tuned to a frequency lower than the natural frequency of said temperature-sensitive crystal for both providing a lagging phase shift at the output of said inverting amplifier and for emitting a near field magnetic signal from said inductor, wherein the frequency of said near field magnetic signal is dependent upon the frequency of the temperature sensitive crystal which is temperature dependent, and wherein said inverting amplifier acts as a switch causing said capacitor to charge and discharge through said inductor, thereby allowing the tank circuit to operate at 2 V b peak-to-peak volts.
Claim 3
Dependent Claim
36 words
The apparatus of claim 1, wherein said tank circuit is connected between the collector of said transistor amplifier and said battery, and said temperature sensitive crystal is connected in the collector/base circuit of the one-transistor amplifier.
Claim 4
Dependent Claim
12 words
The apparatus of claim 2, wherein said battery is a one-cell battery.
Claim 5
Dependent Claim
17 words
The apparatus of claim 2, wherein said temperature sensitive crystal is operating in a Pierce oscillator configuration.
Claim 6
Dependent Claim
28 words
The apparatus of claim 2, wherein a separate RC network is connected to the collector/base circuit of the one transistor amplifier to provide an additional lagging phase shift.
Claim 7
Dependent Claim
13 words
The apparatus of claim 3, wherein said battery is a nickel cadmium battery.
Claim 8
Dependent Claim
231 words
A rechargeable, miniaturized temperature responsive transmitter comprising: a rechargeable battery; an inverting amplifier having an input and output and operably biased to said battery; a temperature sensitive crystal operably coupled between said input and output of said inverting amplifier and having a natural frequency dependent on local temperature; a tank circuit having a first and second terminal with an inductive coil connected therebetween, the first terminal of said tank circuit being connected to said inverting amplifier; a current limiting device connecting said second terminal of said tank circuit to said battery, for limiting the current that can flow into said rechargeable battery; a charging capacitor connected between said second terminal of said tank circuit and ground for storing electrical energy picked up by said inductor; a diode connected between said first terminal of said tank circuit and said ground for rectifying full wave oscillation picked up on the inductor and for charging said charging capacitor; and, wherein said tank circuit is tuned to a frequency lower than the natural frequency of said temperature sensitive crystal, and wherein said tank circuit performs the following functions: i. providing a lagging phase shift at the output of said inverting amplifier; ii. emitting a near field magnetic signal from said inductor at a frequency dependent on the temperature sensitive crystal which is temperature dependent; and, iii. a power pickup used to recharge the rechargeable battery.
Claim 9
Dependent Claim
231 words
A rechargeable, miniaturized temperature responsive transmitter comprising: a rechargeable battery; an inverting amplifier having an input and output and operably biased to said battery; a temperature sensitive crystal operably coupled between said input and output of said inverting amplifier and having a natural frequency dependent on local temperature; a tank circuit having a first and second terminal with an inductive coil connected therebetween, the first terminal of said tank circuit being connected to said inverting amplifier; a current limiting device connecting said second terminal of said tank circuit to said battery, for limiting the current that can flow into said rechargeable battery; a charging capacitor connected between said second terminal of said tank circuit and ground for storing electrical energy picked up by said inductor; a diode connected between said first terminal of said tank circuit and said ground for rectifying full wave oscillation picked up on the inductor and for charging said charging capacitor; and, wherein said tank circuit is tuned to a frequency lower than the natural frequency of said temperature sensitive crystal, and wherein said tank circuit performs the following functions: i. providing a lagging phase shift at the output of said inverting amplifier; ii. emitting a near field magnetic signal from said inductor at a frequency dependent on the temperature sensitive crystal which is temperature dependent; and, iii. a power pickup used to recharge the rechargeable battery.
Claim 10
Dependent Claim
45 words
The apparatus of claim 7, wherein said inverting amplifier is a one transistor amplifier with said tank circuit connected between the collector of said transistor amplifier and said rechargeable battery and said temperature sensitive crystal is connected in the collector/base circuit of said one-transistor amplifier.
Claim 11
Dependent Claim
12 words
The apparatus of claim 8, wherein said battery is a onecell battery.
Claim 12
Dependent Claim
14 words
The apparatus of claim 8, wherein said battery is a rechargeable nickel cadmium battery.
Claim 13
Dependent Claim
17 words
The apparatus of claim 8, wherein said temperature sensitive crystal is operating in a Pierce oscillator configuration.
Claim 14
Dependent Claim
28 words
The apparatus of claim 8, wherein a separate RC network is connected in the collector/base circuit of the one transistor amplifier to provide an additional lagging phase shift.
Claim 15
Dependent Claim
32 words
The apparatus of claim 8, wherein said current limiting device is a JFET that causes current limiting only when the voltage of the inductive coil is more positive than the rechargeable battery.
Claim 16
Dependent Claim
184 words
An ingestible temperature sensing pill comprising: a first cylinder of epoxy encompassing a battery and a transmitter/sensitive circuit, said transmitting/sensing circuit including: an inverting amplifier having an input and output and powered by said battery; a temperature sensitive crystal operably coupled between said input and output of said inverting amplifier and having a natural frequency dependent on local temperature, a tank circuit having a coil inductor, operably coupled between said output of said inverting amplifier and said battery and tuned to a frequency lower than the natural frequency of said temperature sensitive crystal for both providing a lagging phase shift at the output of said inverting amplifier and for emitting a near field magnetic signal from said coil inductor, wherein the frequency of said near field magnetic signal is dependent upon the frequency of the temperature sensitive crystal which is frequency dependent, wherein said coil inductor being wrapped around said first epoxy cylinder but not encompassing said battery; a second epoxy shell encompassing said first cylinder of epoxy and said coil inductor, and, an outer coating of biocompatible material covering said second epoxy shell.
Claim 17
Dependent Claim
184 words
An ingestible temperature sensing pill comprising: a first cylinder of epoxy encompassing a battery and a transmitter/sensitive circuit, said transmitting/sensing circuit including: an inverting amplifier having an input and output and powered by said battery; a temperature sensitive crystal operably coupled between said input and output of said inverting amplifier and having a natural frequency dependent on local temperature, a tank circuit having a coil inductor, operably coupled between said output of said inverting amplifier and said battery and tuned to a frequency lower than the natural frequency of said temperature sensitive crystal for both providing a lagging phase shift at the output of said inverting amplifier and for emitting a near field magnetic signal from said coil inductor, wherein the frequency of said near field magnetic signal is dependent upon the frequency of the temperature sensitive crystal which is frequency dependent, wherein said coil inductor being wrapped around said first epoxy cylinder but not encompassing said battery; a second epoxy shell encompassing said first cylinder of epoxy and said coil inductor, and, an outer coating of biocompatible material covering said second epoxy shell.
Claim 18
Dependent Claim
45 words
The apparatus of claim 14, wherein said inverting amplifier is a one transistor amplifier with the tank circuit connected between the collector of said transistor amplifier and said battery and said temperature sensitive crystal is connected in the collector/base circuit of said one transistor amplifier.
Claim 19
Dependent Claim
16 words
The apparatus of claim 14, wherein said sensing pill is shaped to form an ingestible capsule.
Claim 20
Dependent Claim
19 words
The apparatus of claim 14, wherein said outer coating of biocompatible material is an outer coating of silicone rubber.
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) | 1992-07-03 | 1993-01-02 | 1993-07-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-07-03 | 1997-01-02 | 1997-07-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-07-03 | 2001-01-02 | 2001-07-04 | $7700.00 | Window Closed / Lapsed |