Claims
- 1. A temperature measuring device, comprising: a semiconductor crystal having, an optical high pass characteristic in wavelength terms, the band-edge wavelength between frequencies of maximum and minimum light transmission through said crystal being temperature dependent; a source of light energy of controllable wavelength; first light conducting means for conveying the light energy output of said source to said crystal; a light-to-electric transducer; second light conducting means for conveying light passing from said first light conveying means, through said crystal and to said transducer; scanning means for causing the wavelength of said light energy from said source to vary according to a predetermined function starting from an initial predetermined reference wavelength at least passing through said band-edge wavelength corresponding to all temperatures to be measured; and temperature analog means responsive to said source and said transducer and producing an output signal analagous to the temperature of said crystal as a function of the difference between said predetermined reference wavelength at said band edge.
- 2. The device according to claim 1 in which said temperature analog means measures the scan time between said reference wavelength and the wavelength of said band-edge to produce said output signal analagous to said crystal temperature.
- 3. The device according to claim 1 in which said first and second light conducting means are optical fibers.
- 4. The device according to claim 2 in which said first and second light conducting means are optical fibers.
- 5. The device according to claim 4 in which said source of light energy is a laser diode and said scanning occurs due to the cyclical self-heating of said laser diode when cyclically energized.
- 6. The device according to claim 4 in which said source of light energy is a light emitting diode and said scanning occurs due to the cyclical self-heating of said light emitting diode when cyclically energized.
- 7. Apparatus according to claim 5 in which said temperature analog means is responsive to the junction temperature of said laser diode, said junction temperature being accurately representative of the emitted wavelength of said laser diode.
- 8. Apparatus according to claim 2 in which said source is a broad spectral source and in which said scanning means comprises variable filtering means in the light path between said source and said first light conducting means.
- 9. Apparatus according to claim 8 in which said variable filtering means comprises a second semiconductor crystal and means for cyclically heating said second crystal to produce said variable filtering.
- 10. Apparatus according to claim 8 in which said variable filtering means comprises a monochrometer and mechanical drive means therefor whereby said light energy wavelength is varied.
- 11. Apparatus according to claim 1 in which said semiconductor crystal is an indium phosphite crystal.
- 12. Apparatus according to claim 2 in which said semiconductor crystal is an indium phosphite crystal.
- 13. Apparatus according to claim 9 in which said second crystal is an indium phosphite crystal.
DESCRIPTION
The invention described herein was made in the performance of work under a NASA contract and is subject to the provisions of Section 305 of the National Aeronautics and Space Act of 1958, Public Law 85-568 (72 Stat. 435; U.S.C. 2457).
US Referenced Citations (3)
Number |
Name |
Date |
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4119845 |
Jaskolski et al. |
Oct 1978 |
|
4136566 |
Christensen |
Jan 1979 |
|
4260883 |
Onoda et al. |
Apr 1981 |
|