Semiconductor temperature sensor

• US 4,136,566 A
• Filed: 06/24/1977
• Issued: 01/30/1979
• Est. Priority Date: 06/24/1977
• Status: Expired due to Term

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: University of Utah (State of Utah)
• Inventors: Christensen, Douglas A.
• Primary Examiner(s): Gorenstein, Charles
• Application Number:
  US05/809,593
• Time in Patent Office: 585 Days
• Field of Search: 73/356, 73/362 R, 73/DIG. 11, 356/43, 356/44, 250/226, 250/227, 250/474
• US Class Current: 374/161
• CPC Class Codes: G01K 11/18 of materials which change translucency

Abstract

A temperature sensor utilizing a semiconductor sensing element which absorbs monochromatic radiant energy as a function of temperature. The apparatus includes a monochromatic radiant energy source, radiant energy guide means, a semiconductor sensing element interposed in the radiant energy guide means and a detector for detecting the intensity of the monochromatic radiant energy transmitted by the semiconductor sensing element. Advantageously, optical fibers may be used as the radiant energy guide means for directing the monochromatic radiant energy to the semiconductor and returning the transmitted radiant energy to the detector. The semiconductor sensing element is fabricated from a suitable semiconductor material such as galium arsenide. Additionally, the semiconductor material can be fabricated as a mirror or reflecting prism so that it serves both as the sensing element and as part of the optical components for the radiant energy guide means.

Claims

1. A temperature sensor comprising in combination:

a radiant energy path means comprising a first optical fiber waveguide means and a second optical fiber waveguide means;

sensing means prismatically configurated so as to provide a direct reflective path from said first waveguide means, through said sensing means, to said second waveguide means, said sensing means being fabricated from material which absorbs a portion of a monochromatic radiant energy transmitted along said direct reflective path through said sensing means as a function of temperature;

a monochromatic radiant energy source means optically coupled to said first optical fiber waveguide means, thereby introducing said monochromatic radiant energy into said first optical fiber waveguide means; and

detecting means optically coupled to said second optical fiber waveguide means for detecting the intensity of the monochromatic radiant energy transmitted along said direct reflective path through said sensing means, the detecting means correlating the intensity of the transmitted monochromatic radiant energy with the temperature of the sensing means.

2. The temperature sensor defined in claim 1 wherein the radiation source is operable to emit radiant energy in the near infrared and infrared region of the electromagnetic spectrum.

3. The temperature sensor defined in claim 1 wherein the detecting means further comprises comparing means for comparing intensity of radiant energy emitted by the radiant energy source with the intensity of the energy reflected through said sensing means.

4. The temperature sensor defined in claim 1 wherein the sensing means comprises a bulk semiconductor sample having the characteristic of absorbing radiant energy at a preselected wavelength near the band edge of the semiconductor as a function of temperature.

5. The temperature sensor defined in claim 1 wherein the sensing means comprises a semiconductor having a temperature coefficient of gap energy.

6. The temperature sensor defined in claim 5 wherein the semiconductor is fabricated from galium arsenide.

7. The temperature sensor defined in claim 1 wherein the sensing means is fabricated as a mirror to further improve reflection of the unabsorbed portion of monochromatic radiant energy.

8. A method for sensing temperature in the presence of an electromagnetic field without disturbing said electromagnetic field, the method comprising:

fabricating a temperature sensor from a semiconductor material having an optical transmission characteristic for a preselected wavelength as a function of the temperature of the sensor, said sensor being prismatically configurated so as to provide a direct reflective path through said temperature sensor;

providing a radiation source for said preselected wavelength;

optically coupling the sensor to the radiation source with a first optical fiber waveguide;

providing a detector capable of detecting intensity changes in the radiation transmitted along said direct reflective path through the sensor as a function of temperature;

optically coupling the sensor to the detector with a second optical fiber waveguide; and

sensing temperature by directing the radiation along a direct reflective path from said first optical fiber waveguide through said temperature sensor to said second optical fiber waveguide, and detecting the intensity of the radiation transmitted by the sensor through said second optical fiber waveguide as a function of temperature.