EP0420177B1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Device for wireless measurement of a local physical value
Assignee: Institut fur Mobil-Und Satellitenfunktechnik GmbH
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Filing: 1990-09-26
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Granted: 1995-01-18
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Expires: 2010-09-26
Abstract
Abstract The invention relates to a device for accurately measuring the distribution of local, physical values at a site which is normally inaccessible (for example in living tissue) and for wireless transmission of the measurements and of an identification sign for the transponder transmitting the measurements to an evaluation unit positioned outside the measurement site. By coordinating the measurement to the site of the transponder, the distribution of the physical values to be measured can be determined. Thus, it is possible, for example, to determine the temperature distribution in a tissue fragment, the bending load at different positions of bones, or the body temperature of various laboratory animals in a cage. Since the energy supply is wireless and is effected by means of an electromagnetic field, the service life of the transponders is not limited by exhaustable energy sources. <IMAGE>
Inventors
- 👤 Norbert H.L. Dr.-Ing. Koster
- 👤 Ingo Prof. Dr.-Ing. Wolff
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 11:58
CPC Classifications
A; A61; A61B; A61B5/00; A61B5/0002; A61B5/0004; A61B5/0008; A61B5/01; A61B5/015; A61B2560/00; A61B2560/02; A61B2560/0204; A61B2560/0214; A61B2560/0219
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
319 words
Device for the non-wired measurement of a local physical quantity at a location which exhibits difficult access - having a radio frequency generator (VFO) in the emitted radio frequency electromagnetic field of which a transponder device (Fig. 1) is disposed at the location exhibiting difficult access, which device, in conjunction with a signal generator, generates an audio frequency signal having a fre-quency dependent upon the local physical quantity, - in which the transponder device extracts its operating energy from the electromagnetic field via a reception element with a downstream rectifier and modulates the electromagnetic field with the audio frequency signal generated by the signal generator, - and having a reception device for the modulated electromagnetic field as well as an evaluating device (CPU) which determines from the frequency of the signal generator, its local environmental quantity, - in which the transponder device is a miniaturized transponder, - and an oscillator circuit (LC) is disposed in the transponder as reception element for the electromagnetic field, - and the signal generator (G,R) possesses a working point which is to be identified in non-wired fashion by the evaluating unit (CPU), - and a control circuit connected to the evaluating device (CPU) and the radio frequency generator (VFO) tunes the frequency of the radio frequency generator (VFO) to the frequency of the oscillator circuit (LC) of the transponder. characterized in that the signal generator (G,R) is of such a nature that the generated oscillation frequency increases, at constant local environmental quantity, as the operating voltage increases and, after reaching a maximum value, falls again, in that this control circuit subsequently varies the emitted radio frequency power, so that the transponder is operated at a working point with maximum frequency, in that the evaluating device (CPU) determines the local environmental quantity from a displacement of this maximum frequency and in that the transponder generates an additional identification symbol superposed on the audio frequency signal.
Claim 2
Dependent Claim
25 words
Device according to Claim 1, characterized in that the location exhibiting difficult access is living tissue and the miniaturized transponder is implantable into the tissue.
Claim 3
Dependent Claim
22 words
Device according to Claim 1 or 2, characterized in that, before operation, differing identification symbols were programmed into a plurality of transponders.
Claim 4
Dependent Claim
23 words
Device according to Claim 3, characterized in that the evaluating device (CPU) determines the location of the transponder from the superposed identification symbol.
Claim 5
Dependent Claim
28 words
Device according to one of the preceding claims, characterized in that the superposed identification symbol is digital, i.e. is a digital modulation of the audio frequency measurement signal.
Claim 6
Dependent Claim
51 words
Device according to one of the preceding claims, characterized in that in the radio frequency electromagnetic field a plurality of individually programmed transponders are disposed at various locations exhibiting difficult access, with in each case a reception element (LC), a signal generator with a temperature-dependent element (R) and an identification symbol.
Claim 7
Dependent Claim
18 words
Device according to one of the preceding claims, characterized in that the local physical quantity is the temperature.
Claim 8
Dependent Claim
22 words
Device according to Claim 4, characterized in that a spatial distribution of a local physical quantity, especially a temperature distribution, is determined.
Claim 9
Dependent Claim
26 words
Device according to Claim 4, characterized in that the transponders pick up physical parameters of differing types e.g. pressure and temperature, at the identifiable measurement points.
References Cited (Backward Citations)
No citation records indexed.
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