US4296318A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Opto-electronic instrument for remote temperature measurement
Assignee: CISE Centro Informazioni Studi e Esperienze SpA
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Filing: 1979-09-24
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Granted: 1981-10-20
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Expires: 1999-09-24
Abstract
Abstract An opto-electronic instrument for remote temperature measurement having a measuring probe and a remote supply processing unit connected together by at least one optical fibre. The measuring probe includes at least one polarizer and a temperature sensitive element for receiving, modifying and retransmitting a luminous signal through the fibre which signal has been received from the luminous signal generator of the remote supply processing unit, which unit also includes a variable frequency filter controlled by a ramp generator for transforming the retransmitted luminous signal into a luminous signal, the intensity of which varies sinusoidally with time, and an opto-electrical transducer able to convert this latter luminous signal into a corresponding electrical signal of sinusoidal oscillation for which signal the period of oscillation is then calculated.
Inventors
- 👤 Sergio Mezzetti
- 👤 Pierluigi Pizzolati
- 👤 Francesco Svelto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:36
CPC Classifications
G; G01; G01K; G01K1/00; G01K1/02; G01K1/024; E; E21; E21B; E21B47/00; E21B47/06; E21B47/07; E21B47/12; E21B47/13; E21B47/135; G01K11/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
193 words
An opto-electronic instrument for remote temperature measurement, comprising a measuring probe and a remote supply and processing unit connected together by at least one optical fibre, said supply and processing unit includng a luminous signal generator for said optical fibre, said measuring probe including at least one polariser, and a temperature-sensitive element constituted by a square cross-section parallelepiped crystal of uniaxial double refraction material disposed with its optical axis at 45° to the plane of polarisation of said polariser, to receive the luminous signal transmitted through said optical fibre and to retransmit it to the same optical fibre in the form of a luminous signal the intensity of which varies sinusoidally with the wavelength, and in which the peaks are spaced apart by a distance dependent on the sensed temperature, said supply and processing unit including a variable frequency filter controlled by a ramp generator for transforming said retransmitted luminous signal into a luminous signal the intensity of which varies sinusoidally with time, an opto-electrical transducer able to convert this latter luminous signal into a corresponding electrical signal of sinusoidal oscillation, and means for calculating the period of oscillation of said electrical signal.
Claim 2
Dependent Claim
193 words
An opto-electronic instrument for remote temperature measurement, comprising a measuring probe and a remote supply and processing unit connected together by at least one optical fibre, said supply and processing unit includng a luminous signal generator for said optical fibre, said measuring probe including at least one polariser, and a temperature-sensitive element constituted by a square cross-section parallelepiped crystal of uniaxial double refraction material disposed with its optical axis at 45° to the plane of polarisation of said polariser, to receive the luminous signal transmitted through said optical fibre and to retransmit it to the same optical fibre in the form of a luminous signal the intensity of which varies sinusoidally with the wavelength, and in which the peaks are spaced apart by a distance dependent on the sensed temperature, said supply and processing unit including a variable frequency filter controlled by a ramp generator for transforming said retransmitted luminous signal into a luminous signal the intensity of which varies sinusoidally with time, an opto-electrical transducer able to convert this latter luminous signal into a corresponding electrical signal of sinusoidal oscillation, and means for calculating the period of oscillation of said electrical signal.
Claim 3
Dependent Claim
20 words
An instrument as claimed in claim 1, wherein said crystal of uniaxial double refraction material is a lithium niobate crystal.
Claim 4
Dependent Claim
19 words
An instrument as claimed in claim 2, wherein said lithium niobate crystal is provided with a reflecting end face.
Claim 5
Dependent Claim
14 words
An instrument as claimed in claim 2, wherein said polariser is a Nicol prism.
Claim 6
Dependent Claim
30 words
An instrument as claimed in claim 1, wherein said measuring probe comprises an optical connector provided with a quartz collimating lens and disposed between said optical fibre and said polariser.
Claim 7
Dependent Claim
50 words
An instrument as claimed in claim 1, wherein said variable filter comprises a collimation lens, a band pass filter and a tunable cavity controlled by said ramp generator in such a manner that for each voltage generated by this latter there is a corresponding different tuning wavelength of said cavity.
Claim 8
Dependent Claim
63 words
An instrument as claimed in claim 1, wherein said calculation means comprise a first counter activated by said ramp generator so that it counts a predetermined number of periods of oscillation of said electrical signal, and a second counter activated by the first counter so that it counts the pulses emitted by a fixed frequency oscillator until counting by said first counter terminates.
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) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |