Method of measuring temperature

• US 6,283,632 B1
• Filed: 12/06/1999
• Issued: 09/04/2001
• Est. Priority Date: 11/25/1992
• Status: Expired due to Term

• Current Assignee: Terumo Cardiovascular Systems Corporation (Terumo Corporation)
• Original Assignee: Terumo Cardiovascular Systems Corporation (Terumo Corporation)
• Inventors: Takaki, Shunsuke
• Primary Examiner(s): Gutierrez, Diego
• Assistant Examiner(s): Guadalupe, Yaritza
• Application Number:
  US09/455,165
• Time in Patent Office: 638 Days
• Field of Search: 374/161, 374/1
• US Class Current: 374/161
• CPC Class Codes: G01K 11/18 of materials which change translucency
• CPC Class Codes: G01K 11/3206 at discrete locations in the fibre, e.g. using Bragg scattering

Abstract

A method of measuring temperature including the steps of calibrating a sensor disposed near one end of an optical fiber, the sensor having a source of light which irradiates light, the optical fiber being positioned at one end to receive light from the source of light; a transducer positioned near the other end of the optical fiber, the transducer being made up of at least two polymers that have refractive indices with different temperature dependencies and form a microphase separation structure; a reflection element for reflecting the irradiated light; and an arithmetic processing unit which receives the reflected light by exposing the sensor to two or more sources of heat whose values are known; and exposing the sensor to the portion whose temperature is to be measured.

Claims

1. A method of measuring temperature comprising the steps of:

calibrating a temperature sensor comprising;

a source of light which irradiates light;

an optical fiber positioned to receive light from the source of light;

a transducer positioned near an end of the optical fiber opposite the source of light, the transducer being made up of at least two polymers that have refractive indices with different temperature dependencies and form a microphase separation structure, wherein the polymers are cured products made from a cationically polymerizable compound having epoxy groups and a radically polymerizable compound having radically unsaturated groups;

a reflection means positioned near the transducer end of the optical fiber for reflecting the irradiated light;

a light sensor for receiving the reflected light; and

an arithmetic processing unit which calculates a temperature based upon the reflected light received by said light sensor and by exposing the sensor to two or more sources of heat whose values are known

exposing the sensor to a portion whose temperature is to be measured; and

determining the temperature of the portion by providing light from said source of light to said transducer, receiving reflected light from said transducer and reflection means using said light sensor and calculating the temperature of said portion using said arithmetic processing unit and based on said reflected light received by said light sensor.

2. The method of claim 1, wherein the temperature sensor further comprises a light sensor for receiving the reflected light.

3. The method of claim 2, wherein the light sensor is selected from the group consisting of photodiodes and photomultipliers.

4. The method of claim 1, wherein the arithmetic processing unit receives the reflected light and calculates the temperature of the portion being measured.

5. The method of claim 1, wherein the microphase separation structure comprises a domain phase structure having a length greater than the wavelength of light emitted by the light source and a base phase surrounding the domain phase structure.

6. The method of claim 5, wherein the domain phase structure is in the form of dispersed particles having an average diameter between 1 and 10 microns.

7. The method of claim 1, wherein the sensor further comprises a transparent blood flow cell, the polymers of the transducer being mounted on an inside wall of the blood flow cell.

8. The method of claim 1, wherein the reflection means comprises a reflector plate integrally fitted to the transducer.

9. The method of claim 8, wherein the reflector plate is a metal film selected from the group consisting of silver, gold and aluminum.

10. The method of claim 1, wherein the cationically polymerizable compound is an epoxy resin.

11. The method of claim 1, wherein the radically polymerizable compound is selected from the group consisting of acrylic and methacrylic resins.

12. The method of claim 1, wherein the optical fiber comprises a bundle of individual filaments.

13. The method of claim 12, wherein the bundle is branched into two portions at one end such that one portion is positioned to receive light from the light source and is positioned to transmit reflected light to the light sensor.

14. The method of claim 1, wherein the temperature sensor has a diameter smaller than 1 mm.

15. The method of claim 1, wherein the polymers have a difference in refractive index greater than 0.001 over a temperature range of between 25 and 45°

C.

16. The method of claim 1, wherein the temperature to be measured is between about 25°

C. and about 45°

C.

17. A method of measuring temperature comprising the steps of:

calibrating a temperature sensor comprising;

a source of light which irradiates light;

an optical fiber positioned to receive light from the source of light;

a transducer positioned near an end of the optical fiber opposite the source of light, the transducer being made up of at least two polymers that have refractive indices with different temperature dependencies and form a microphase separation structure;

a reflection means positioned near the transducer end of the optical fiber for reflecting the irradiated light;

a light sensor for receiving the reflected light; and

an an arithmetic processing unit which calculates a temperature based upon the reflected light received by said light sensor and by exposing the sensor to two or more sources of heat whose values are known;

exposing the sensor to a portion of a living body whose temperature is to be measured; and

determining the temperature of the portion by providing light from said source of light to said tranducer, receiving light from said tranducer and reflection means using said light sensor and calculating the temperature of said portion using said arithmetic processing unit and based on said reflected light received by said light sensor.

18. The method of claim 17, wherein the polymers are cured products made from a cationically polymerizable compound having epoxy groups and a radically polymerizable compound having radically unsaturated groups.

19. The method of claim 17, wherein the temperature to be measured is between about 25°

C. and about 45°

C.

20. A method of measuring temperature comprising the steps of:

calibrating a temperature sensor comprising;

a source of light which irradiates light;

an optical fiber positioned to receive light from the source of light;

a transducer positioned near an end of the optical fiber opposite the source of light, the transducer being made up of at least two polymers that have refractive indices with different temperature dependencies and form a microphase separation structure;

a reflection means positioned near the transducer end of the optical fiber for reflecting the irradiated light;

a light sensor for receiving the reflected light; and

an arithmetic processing unit which calculates a temperature based upon the reflected light received by said light sensor and by exposing the sensor to two or more sources of heat whose values are known;

exposing the sensor to a portion whose temperature is to be measured; and

determining the temperature of the portion by providing light from said source of light to said transducer, receiving reflected light from said transducer and reflection means using said light sensor and calculating the temperature of said portion using said arithmetic processing unit and based on said reflected light received by said light sensor wherein the temperature being measured is in an extracorporeal blood circuit.

21. The method of claim 20 wherein the polymers are cured products made from a cationically polymerizable compound having epoxy groups and a radically polymerizable compound having radically unsaturated groups.

22. The method of claim 20, wherein the temperature to be measured is between about 25°

C. and about 45°

C.