Radiation clinical thermometer

• US 6,572,264 B1
• Filed: 08/11/2000
• Issued: 06/03/2003
• Est. Priority Date: 12/15/1998
• Status: Expired due to Fees

• Current Assignee: Citizen Holdings Co., Ltd. (Citizen Electronics Company Limited)
• Original Assignee: Citizen Watch Co Limited (Citizen Electronics Company Limited)
• Inventors: Egawa, Shunji
• Primary Examiner(s): Gutierrez, Diego
• Assistant Examiner(s): Verbitsky, Gail
• Application Number:
  US09/622,149
• Time in Patent Office: 1,026 Days
• Field of Search: 374/126, 374/128, 374/129, 374/132, 702/130, 702/131, 702/135-136, 702/FOR.142, 600/474
• US Class Current: 374/133
• CPC Class Codes: G01J 5/0003 for sensing the radiant heat transfer of samples, e.g. emittance meter
• CPC Class Codes: G01J 5/0011 Ear thermometers G01J5/021 and G01J5/049 take precedence
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/025 Interfacing a pyrometer to an external device or network; User interface
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/04 Casings
• CPC Class Codes: G01J 5/049 Casings for tympanic thermometers
• CPC Class Codes: G01J 5/05 Means for preventing contamination of the components of the optical system; Means for preventing obstruction of the radiation path
• CPC Class Codes: G01J 5/064 Ambient temperature sensor; Housing temperature sensor; Constructional details thereof
• CPC Class Codes: G01J 5/08 Optical arrangements
• CPC Class Codes: G01J 5/0818 Waveguides
• CPC Class Codes: G01J 5/0875 Windows; Arrangements for fastening thereof
• CPC Class Codes: G01J 5/16 Arrangements with respect to the cold junction; Compensating influence of ambient temperature or other variables
• CPC Class Codes: G01J 5/70 Passive compensation of pyrometer measurements, e.g. using ambient temperature sensing or sensing of temperature within housing
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52

Abstract

To provide a radiation thermometer capable of measuring a body temperature more accurately than it has been conventionally possible, by taking into account an infrared ray that is emitted from a front end of the probe portion and reflected from an eardrum or an external acoustic opening. The radiation thermometer has body temperature calculating means for calculating a body temperature according to a predetermined arithmetic expression based on an emissivity when the emissivity of the eardrum or the external acoustic opening is less than 1, an output of infrared-ray detecting means and an output of temperature-measuring means.

Claims

1. A radiation thermometer comprising:

infrared-ray detecting means;

a probe portion having a front end to be inserted into a hole portion of a living being and an introduction opening provided at the front end for guiding an infrared ray emitted from the hole portion of the living being to the infrared-ray detecting means;

temperature-measuring means for measuring a temperature of the probe portion; and

calculating means for calculating a body temperature of the living being based on output of the infrared-ray detecting means and output of the temperature-measuring means,

wherein said probe portion has such a shape as to fill almost the hole portion of the living being while the probe portion is being inserted into the hole portion of the living being; and

wherein said calculating means calculates the body temperature of said living being by correcting an error caused by the infrared ray radiated from the probe portion inserted into the hole portion of the living being, reflected inside the hole portion and emitted into the introduction opening.

2. A radiation thermometer according to claim 1, wherein said calculating means calculates the body temperature of the living being according to a predetermined arithmetic expression based on the output of said temperature-measuring means and an emissivity of the hole portion of the living being and said correction is made by setting the emissivity to be less than 1.

3. A radiation thermometer according to claim 2, wherein the calculating means includes a processing for dividing an output of the infrared-ray detecting means by the emissivity.

4. A radiation thermometer according to claim 1, wherein the temperature-measuring means serves as temperature-measuring means for measuring a temperature of the infrared-ray detecting means.

5. A radiation thermometer according to claim 1, wherein the temperature-measuring means comprises a first temperature-measuring means for measuring a temperature of the probe portion and a second temperature-measuring means for measuring a temperature of the infrared-ray detecting means.

6. A radiation thermometer according to claim 2, wherein the predetermined arithmetic expression is

7. A radiation thermometer according to claim 2, wherein the predetermined arithmetic expression is a linear expression that approximates a temperature (T_b) of the hole portion of the living being by a temperature (T₀) of the infrared-ray detecting means, an output (V_b) of the infrared-ray detecting means, and an emissivity (e) of the hole portion of the living being.

8. A radiation thermometer according to claim 7, wherein the predetermined arithmetic expression is

9. A radiation thermometer according to claim 2, wherein the predetermined arithmetic expression is

10. A radiation thermometer according to claim 5, wherein the probe portion has a light-guiding pipe for guiding an infrared ray emitted from the introduction opening to the infrared ray sensor and case means for covering the light-guiding pipe, with a space formed between the light-guiding pipe and the case means, and the second temperature-measuring means is provided between the case means and the light-guiding pipe such that the second temperature-measuring means is in contact with the case means but is not in contact with the light-guiding pipe.

11. A radiation thermometer according to claim 1, wherein a member of the front end of the probe portion has a thermal capacity to such extent that a temperature does not change suddenly during a period of time required for calculating a body temperature of the living being.

12. A radiation thermometer according to claim 11, wherein a material of the front end of the probe portion is a window member provided at the introduction opening.

13. A radiation thermometer according to claim 12, wherein the window member is made of calcium fluoride, silicon or barium fluoride having a thickness of 0.3 mm or more.

14. A radiation thermometer according to claim 1, wherein the hole portion of the living being is an external acoustic opening of a human being, and the emissivity is set to 0.90 to 0.98.

15. A radiation thermometer according claim 1, wherein the radiation thermometer has emissivity setting means for setting the emissivity.

16. A radiation thermometer according to claim 1, wherein the radiation thermometer has a peak value detecting means for detecting a peak value of the infrared-ray detecting means, and an output of the infrared-ray detecting means that is used by the calculating means for the calculation is the peak value.

17. A radiation thermometer according to claim 2 further comprising emissivity selecting means for setting the emissivity of said hole portion of the living being to be either less than 1 or 1.

18. A radiation thermometer according to claim 17, wherein the radiation thermometer has a measuring switch for starting a measuring operation, and the emissivity selecting means selects an emissivity according to the operation of the measuring switch.