Optical temperature probe

• US 4,016,761 A
• Filed: 04/18/1974
• Issued: 04/12/1977
• Est. Priority Date: 04/18/1974
• Status: Expired due to Term

• Current Assignee: University of Utah Research Foundation (State of Utah)
• Original Assignee: the united states of america as represented by the secretary of the navy
• Inventors: Johnson, Curtis, Durney, Carl, Lords, James, Rozzell, Thomas C.
• Primary Examiner(s): Queisser, Richard C.
• Assistant Examiner(s): Appleman, John S.
• Application Number:
  US05/461,834
• Time in Patent Office: 1,090 Days
• Field of Search: 73/339 R, 73/356, 73/355 R, 73/355 EM, 356/44, 356/45
• US Class Current: 374/161
• CPC Class Codes: G01K 11/12 using changes in colour, translucency or reflectance

Abstract

A temperature probe measures temperature changes of biological tissue whilehe tissue is being irradiated with microwaves. The temperature probe is completely nonmetallic to minimize perturbation of the microwave field, and the structure of the probe includes a plurality of optic fibers which carry light to and from a reflective liquid crystal film. The liquid crystal is enclosed in a housing at the tip of the probe which is in contact with the biological tissue, and the liquid crystal undergoes changes in absolute reflectance proportional to the temperature changes of the tissue. The optic fibers are gathered in a bundle with a first portion of the bundle transmitting light from a light generation device to the liquid crystal and the remainder of the bundle transmitting reflected light from the crystal back to a photo transistor. The reflected light received by the photo transistor is converted into an electrical signal and displayed as a representation of temperature.

Claims

1. A temperature probe which is adapted to be implanted in a material whose temperature is to be measured comprising:

an optic fiber bundle having first and second groups of optic fibers which are physically separated at one end of said bundle;

a temperature sensitive element adapted to be implanted in said material to be measured and in close proximity to the other end of said bundle;

means for maintaining said element in an airtight relationship to said other end of said bundle, said element having light reflective properties which are responsive to temperature changes; and

light source adjacent to said first group of optic fibers at said one end of said bundle, and a light responsive element adjacent the second group of optic fibers at said one end of said bundle.

2. A temperature probe as defined in claim 1 wherein said temperature sensitive element is a liquid crystal film.

3. A temperature probe as defined in claim 2 wherein said liquid crystal film is a mixture of cholesteryl pelangonate, cholesteryl oleyl carbonate, and cholesteryl chloride.

4. A temperature probe as defined in claim 1 wherein said light source is a red gallium arsenide phosphide light emitting diode.

5. A temperature probe as defined in claim 1 wherein said light source is a green light emitting diode.

6. A temperature probe as defined in claim 1 wherein said temperature sensitive element is a film of liquid crystal mixture sealed in an opaque capsule.

7. A temperature probe for use with light-generating means comprising:

an optic fiber bundle having first and second groups of optical fibers, said first group of optic fibers conducting light from light-generating means to a specimen;

temperature-sensitive means, having specific internal light-reflectance characteristics, in contact with the end of the fiber optic bundle near said specimen, said temperature-sensitive means being responsive to temperature changes of said specimen whereby said internal light-reflectance characteristics are varied in proportion to said temperature changes; and

light-responsive means responsive to the intensity of light impinging thereon, said second group of optic fibers receiving light internally reflected by scattering from the material comprising said temperature-sensitive means and conducting it to said light-responsive means, said light-responsive means converting said light into an electrical signal proportional to the intensity of the light reflected thereon from said temperature-sensitive means;

wherein said temperature sensitive means is a liquid crystal material.

8. A temperature probe capable of being implanted in a specimen whose temperature is to be measured comprising:

an optic fiber bundle having first and second groups of optic fibers which are physically separated at one end of said bundle and intermingled at the other end of said bundle;

a temperature sensitive element in contact with said specimen and in close proximity to said other end of said bundle, said element having light reflective properties responsive to temperature changes;

means for maintaining said element in an air-tight relationship to said other end of said bundle; and

light source adjacent to said first group of optic fibers at said one end of said bundle, and a light responsive means adjacent said second group of optic fibers at said one end of said bundle.

9. The temperature of claim 8 wherein said probe further includes a housing, said housing having a first section for supporting said light source and said light responsive means, and a second section detachable from said first section for supporting said first and second groups of optic fibers adjacent said light source and said light responsive means respectively.

10. The temperature probe of claim 9 wherein said housing further includes a means for securing said first section to said second section.

11. A temperature probe for directly engaging a material whose temperature is to be measured comprising:

a slender optic fiber bundle having first and second groups of optic fibers physically separated at one end of said bundle;

a temperature sensitive element adapted to directly engage the material to be measured in close proximity to the other end of said bundle, said element having light reflective properties which are responsive to temperature changes;

means for maintaining said element in an air-tight relation to said other end of said bundle;

a light source contacting said first group of optic fibers at said one end of said bundle; and

light responsive means contacting the second group of optic fibers at said one end of said bundle.