US4437761A
Expired / Lapsed
US
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Refractive index temperature sensor
Assignee: Unisys Corp
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Filing: 1981-03-27
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Granted: 1984-03-20
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Expires: 2001-03-27
Abstract
Abstract An optical temperature sensor and method of manufacture therefor in which the intensity of light reflected from a first dielectric interface or from first and second dielectric interfaces, wherein one of the dielectrics has a temperature dependent index of refraction is measured. The intensity of light refleted from such dielectric interfaces will vary depending on the index of refraction which in turn is temperature dependent, thus providing a temperature dependent light signal.
Inventors
- 👤 Harry Kroger
- 👤 Richard A. Soref
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:14
CPC Classifications
G; G01; G01K; G01K11/00; G01K11/12; G01K11/14
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
80 words
An apparatus for measuring temperature comprising: means for guiding light having a first index of refraction n 1 ; and sensor material having first and second surfaces, a temperature dependent index of refraction n 2 , and a smoothly varying absorption characteristic to reduce reflections from said second surface, said first surface aligned with said light guiding means to form a dielectric interface therebetween whereby light incident to said interface is reflected therefrom with an intensity that varies with temperature.
Claim 2
Independent Claim
80 words
An apparatus for measuring temperature comprising: means for guiding light having a first index of refraction n 1 ; and sensor material having first and second surfaces, a temperature dependent index of refraction n 2 , and a smoothly varying absorption characteristic to reduce reflections from said second surface, said first surface aligned with said light guiding means to form a dielectric interface therebetween whereby light incident to said interface is reflected therefrom with an intensity that varies with temperature.
Claim 3
Dependent Claim
15 words
The apparatus according to claim 1 wherein said light guiding means comprises an optical fiber.
Claim 4
Dependent Claim
13 words
The apparatus according to claim 2 wherein said sensor material comprises semiconductor material.
Claim 5
Dependent Claim
14 words
The apparatus according to claim 3 wherein said semiconductor material comprises amorphous hydrogenated silicon.
Claim 6
Dependent Claim
16 words
The apparatus according to claim 4 wherein said amorphous hydrogenated silicon comprises at least 80% silicon.
Claim 7
Dependent Claim
43 words
The apparatus according to claim 4 wherein said amorphous hydrogenated silicon comprises a hydrogenated amorphous silicon material having a varying ratio of silicon to hydrogen graded substantially smoothly from said first surface to said second surface to establish said smoothly varying absorption characteristics.
Claim 8
Dependent Claim
37 words
The apparatus according to claim 6 wherein said graded amorphous hydrogenated silicon varies from a high ratio of hydrogen to silicon at said first surface to a lower ratio of hydrogen to silicon at said second surface.
Claim 9
Dependent Claim
29 words
The temperature sensor according to claim 3 wherein said semiconductor material has a band gap energy that is greater than energy levels of said light received at said interface.
Claim 10
Dependent Claim
103 words
In a temperature sensor, the combination comprising: optical fiber means having a first index of refraction n 1 for guiding light; semiconductor sensor material having a temperature dependent index of refraction n 2 , first and second surfaces, and a smoothly varying absorption characteristic between said first and second surfaces, said first surface aligned with said optical fiber means, to form a dielectric interface; to provide reflectance power that raises with said index of refraction n 2 means for detecting intensity of light reflected from said interface to determine said reflectance power; and means coupled to receive said reflectance power for determing temperature.
Claim 11
Dependent Claim
103 words
In a temperature sensor, the combination comprising: optical fiber means having a first index of refraction n 1 for guiding light; semiconductor sensor material having a temperature dependent index of refraction n 2 , first and second surfaces, and a smoothly varying absorption characteristic between said first and second surfaces, said first surface aligned with said optical fiber means, to form a dielectric interface; to provide reflectance power that raises with said index of refraction n 2 means for detecting intensity of light reflected from said interface to determine said reflectance power; and means coupled to receive said reflectance power for determing temperature.
Claim 12
Dependent Claim
41 words
The apparatus according to claim 9 further comprising optical coupling means adapted to receive light from an external optical source for guiding said light to said sensor material and reflected light from said dielectric interface to said reflected light determining means.
Claim 13
Dependent Claim
126 words
The apparatus according to claim 9 further comprising: optical coupling means having means for receiving light from an external optical source, for guiding said light received from said external optical source to first terminal means and light reflected from said dielectric interface to second terminal means; and wherein said reflected light detecting means comprises: first detector means coupled to said first terminal means for detecting intensity of light incident thereto and providing a first signal representative thereof; second detector means coupled to said second terminal means for detecting intensity of light incident thereto and for providing a second signal indicative thereof; and difference means adapted to receive said first and second signals for providing a third signal representative of differences between said first and second signals.
Claim 14
Independent Claim
158 words
An apparatus for measuring temperature comprising: means having a first index of refraction n 1 for guiding light; sensor material means having a temperature dependent index of refraction n 2 , n 2 having a value n 2 ' at a predetermined reference temperature, and first and second surfaces in substantially parallel alignment, said first surface being aligned with said light guiding means and forming a first interface therebetween for reflecting light incident thereon; and means for reflection having third and fourth surfaces, said third surface aligned with said second surface, thereby forming a second interface for reflecting light incident thereon, said light reflected from said first and second interfaces interfering in constructive an destructive relation to provide reflectance power that varies with tremperature: said first and second surfaces of said sensor material means having spacing therebetween to cause and reflectance power to vary with said refractive index n 2 substantially linearly about said value n 2 .
Claim 15
Independent Claim
158 words
An apparatus for measuring temperature comprising: means having a first index of refraction n 1 for guiding light; sensor material means having a temperature dependent index of refraction n 2 , n 2 having a value n 2 ' at a predetermined reference temperature, and first and second surfaces in substantially parallel alignment, said first surface being aligned with said light guiding means and forming a first interface therebetween for reflecting light incident thereon; and means for reflection having third and fourth surfaces, said third surface aligned with said second surface, thereby forming a second interface for reflecting light incident thereon, said light reflected from said first and second interfaces interfering in constructive an destructive relation to provide reflectance power that varies with tremperature: said first and second surfaces of said sensor material means having spacing therebetween to cause and reflectance power to vary with said refractive index n 2 substantially linearly about said value n 2 .
Claim 16
Dependent Claim
14 words
The temperature sensor according to claim 12 wherein said sensor material comprises a semiconductor.
Claim 17
Dependent Claim
15 words
The temperature sensor according to claim 13 wherein said sensor material comprises amorphous hydrogenated silicon.
Claim 18
Dependent Claim
34 words
The temperature sensor according to claim 13 wherein said means for reflection includes a dielectric material having index of refractions n 3 for reflecting said light incident upon said second interface by dielectric reflection.
Claim 19
Dependent Claim
27 words
The temperature sensor according to claim 13 wherein said reflection means further comprises: absorbing means aligned with said fourth surface for absorbing substantially all light incident thereon.
Claim 20
Dependent Claim
25 words
The apparatus according to claim 12 wherein said reflection means comprises metallic material aligned with said sensor material second surface for reflecting light incident thereupon.
Claim 21
Dependent Claim
158 words
In a temperature sensor, the combination comprising: optical fiber means for guiding light having a first index of refraction n 1 ; semiconductor sensor material means having a temperature dependent index of refraction n 2 , n 2 having a value n 2 ' at a predetermined temperature, and having first and second surfaces in substantially parallel alignment, said first surface being aligned with said optical fiber means and forming a first interface therebetween for reflecting light incident thereto; means having third and fourth surfaces, said third surface being aligned with said second surface to form a second interface for reflecting light incident thereon to provide reflectance power that varies with temperature; said first and second surfaces of said sensor material means having spacing therebetween such that said reflectance power varies with said refractive index substantially liearly about said value n 2 '; and means for detecting intensity of said light reflected from said first and second interfaces.
Claim 22
Dependent Claim
158 words
In a temperature sensor, the combination comprising: optical fiber means for guiding light having a first index of refraction n 1 ; semiconductor sensor material means having a temperature dependent index of refraction n 2 , n 2 having a value n 2 ' at a predetermined temperature, and having first and second surfaces in substantially parallel alignment, said first surface being aligned with said optical fiber means and forming a first interface therebetween for reflecting light incident thereto; means having third and fourth surfaces, said third surface being aligned with said second surface to form a second interface for reflecting light incident thereon to provide reflectance power that varies with temperature; said first and second surfaces of said sensor material means having spacing therebetween such that said reflectance power varies with said refractive index substantially liearly about said value n 2 '; and means for detecting intensity of said light reflected from said first and second interfaces.
Claim 23
Dependent Claim
65 words
The temperature sensor according to claim 18 further comprising: optical coupling means having first terminal means for receiving light, second terminal means coupled to said sensor material and third terminal means, coupled to said detector means, for guiding light received at said first terminal means to said sensor material and for coupling light reflected from said first and second dielectric interfaces to said detector means.
Claim 24
Dependent Claim
143 words
The temperature sensor according to claim 18 further comprising: optical coupling means having first terminal means adapted to receive light from an external source second terminal means coupled to said sensor material means, and third and fourth terminal means, for guiding light received at said first terminal means to said sensor means and said third terminal means and for guiding light reflected from said sensor means to said fourth terminal means; first detector means coupled to said third terminal means for detecting intensity of light coupled from said first terminal means and for providing a first signal representative thereof; second detector means coupled to said fourth terminal means for detecting intensity of light received therefrom and for providing a second signal representative thereof; and difference means for determining differences between said first and second signals and for providing a third signal representative thereof.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-03-20 | 1987-09-19 | 1988-03-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-03-20 | 1991-09-19 | 1992-03-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-03-20 | 1995-09-19 | 1996-03-20 | $7700.00 | Window Closed / Lapsed |