Concentration measuring method

• US 10,241,034 B2
• Filed: 08/24/2015
• Issued: 03/26/2019
• Est. Priority Date: 08/29/2014
• Status: Active Grant

• Current Assignee: Fujikin Incorporated, Tohoku University National Universities Corporation
• Original Assignee: Tohoku University National Universities Corporation
• Inventors: Sugawa, Shigetoshi, Kuroda, Rihito
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US15/506,440
• Publication Number:
  US 20170254746A1
• Time in Patent Office: 1,310 Days
• CPC Class Codes: A61B 2505/07 Home care
• CPC Class Codes: A61B 5/1112 Global tracking of patients, e.g. by using GPS
• CPC Class Codes: A61B 5/1122 of movement trajectories
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14535 for measuring haematocrit
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/1477 non-invasive
• CPC Class Codes: A61B 5/4227 endocrine glands, i.e. thyroid, adrenals, hypothalamic, pituitary
• CPC Class Codes: A61B 5/6898 Portable consumer electronic devices, e.g. music players, telephones, tablet computers
• CPC Class Codes: G01N 2021/158 Eliminating condensation
• CPC Class Codes: G01N 2021/3159 Special features of multiplexing circuits
• CPC Class Codes: G01N 2021/3181 using LEDs
• CPC Class Codes: G01N 21/031 Multipass arrangements
• CPC Class Codes: G01N 21/0332 with temperature control control of temperature G05D23/00; cryostats F17C3/08
• CPC Class Codes: G01N 21/31 Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry G01N21/72 takes precedence
• CPC Class Codes: G01N 21/3151 using two sources of radiation of different wavelengths G01N21/33 - G01N21/39 take precedence
• CPC Class Codes: G01N 21/35 using infrared light G01N21/39 takes precedence
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 2201/08 Optical fibres; light guides

Abstract

A concentration measurement method accurately, quickly, and non-destructively measures the concentration of a predetermined chemical component within an object to a nano-order trace concentration level in real time. A time sharing method irradiates the object light of a first wavelength and light of a second wavelength having different light absorption rates with respect to the object to be measured. Light of both wavelengths that arrives optically through the object is received by a shared light reception sensor, and signals respectively relating to light of the first and second wavelengths are output from the light reception sensor in accordance with the received light. A differential signal of these signals is formed, and the concentration of a chemical component in the object to be measured is derived on the basis of the differential signal.

Claims

1. A concentration measuring method for optically measuring a concentration of a predetermined chemical component in an object to be measured, the method comprising the steps of:

irradiating at least light (1) having a first wavelength (λ

1) that has an absorbability with respect to the chemical component, and light (2) having a second wavelength (λ

2) that has no or substantially no absorbability with respect to the chemical component, or an absorbability that is relatively lower than that of the light (1), from light-emitting unit toward the object to be measured using a time-sharing method;

sequentially receiving the light that is produced by the irradiation and passes through the object to be measured by light-receiving unit;

inputting a first light-receiving signal (1) based on the light (1) and a second light-receiving signal (2) based on the light (2), each produced by the received light into differential signal forming unit;

deriving the concentration of the predetermined chemical component from a measured value based on a differential signal output from the differential signal forming unit in accordance with the input, and data stored in storage unit in advance; and

feeding back a feedback signal corresponding to the differential signal to light emission amount control unit for controlling a light emission amount of the light-emitting unit and/or the differential signal forming unit.

2. The concentration measuring method according to claim 1, wherein the object to be measured is in a gas state.

3. The concentration measuring method according claim 1, wherein the object to be measured is in a liquid state.

4. The concentration measuring method according to claim 1, wherein the object to be measured is a fruit or a vegetable.

5. The concentration measuring method according to claim 1, wherein the light-emitting unit comprises a light source that emits the light having the first wavelength and a light source that emits the light having the second wavelength.

6. The concentration measuring method according to claim 1, wherein the light-emitting unit comprises a light source that emits the light having the first wavelength and the light having the second wavelength.

7. The concentration measuring method according to claim 6, wherein irradiation using the time-sharing method is performed by propagating the light through irradiation optical paths in which the optical axes of the emitted light and received light are the same or substantially the same.

8. A concentration measuring method for optically measuring a concentration of a predetermined chemical component in an object to be measured, the method comprising the steps of:

irradiating at least light having a first wavelength that has an absorbability with respect to the chemical component, and light having a second wavelength that has no or substantially no absorbability with respect to the chemical component, or an absorbability that is relatively lower than that of the light having the first wavelength, from a single light-emitting unit toward the object to be measured using a time-sharing method;

sequentially receiving the light that is produced by the irradiation and passes through the object to be measured in a time-sharing manner by a single light-receiving unit;

inputting a first light-receiving signal based on the light having the first wavelength and a second light-receiving signal based on the light having the second wavelength, each produced by the received light, into differential signal forming unit;

deriving the concentration of the predetermined chemical component from a measured value based on an output signal output from the differential signal forming unit in accordance with the input, and data stored in storage unit in advance; and

controlling a light emission amount of the light-emitting unit on the basis of a feedback signal corresponding to the differential signal.

9. The concentration measuring method according to claim 8, wherein the object to be measured is in a gas state.

10. The concentration measuring method according claim 8, wherein the object to be measured is in a liquid state.

11. The concentration measuring method according to claim 8, wherein the object to be measured is a fruit or a vegetable.

12. The concentration measuring method according to claim 8, wherein the light-emitting unit comprises a light source that emits the light having the first wavelength and a light source that emits the light having the second wavelength.

13. The concentration measuring method according to claim 8, wherein the light-emitting unit comprises a light source that emits the light having the first wavelength and the light having the second wavelength.

14. A concentration measuring method, comprising the steps of:

irradiating at least light having a first wavelength and light having a second wavelength, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;

sequentially receiving the light of each wavelength that optically passes through the object to be measured as a result of the irradiation of the light of each wavelength, using a common light-receiving sensor;

forming a differential signal between a signal related to the light having the first wavelength and a signal related to the light having the second wavelength output from the light-receiving sensor in accordance with the received light;

deriving a concentration of a chemical component in the object to be measured on the basis of the differential signal; and

controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.

15. The concentration measuring method according to claim 14, wherein the object to be measured is in a gas state.

16. The concentration measuring method according claim 14, wherein the object to be measured is in a liquid state.

17. The concentration measuring method according to claim 14, wherein the object to be measured is a fruit or a vegetable.

18. A concentration measuring method, comprising the steps of:

irradiating at least a first light and a second light, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;

receiving each light that optically passes through the object to be measured by irradiation of each light onto the object to be measured, using a common light-receiving sensor;

forming a differential signal on the basis of a signal related to the first light and a signal related to the second light output from the light-receiving sensor in accordance with the received light;

deriving a concentration of a predetermined chemical component in the object to be measured on the basis of the differential signal; and

controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.

19. A concentration measuring method, comprising the steps of:

irradiating at least light having a first wavelength and light having a second wavelength, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;

receiving the light of each wavelength that optically passes through the object to be measured as a result of the irradiation of the light of each wavelength, using a common light-receiving sensor;

forming a differential signal between a signal related to the light having the first wavelength and a signal related to the light having the second wavelength output from the light-receiving sensor in accordance with the received light;

deriving a concentration of a chemical component in the object to be measured on the basis of the differential signal; and

controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.

20. A concentration measuring method, comprising the steps of:

irradiating at least a first light and a second light, each having a different light absorptivity with respect to an object to be measured, onto the object to be measured using a time-sharing method;

receiving each light that optically passes through the object to be measured by irradiation of each light onto the object to be measured, using a common light-receiving sensor;

forming a differential signal on the basis of a signal related to the first light and a signal related to the second light output from the light-receiving sensor in accordance with the received light;

deriving a concentration of a predetermined chemical component in the object to be measured on the basis of the differential signal; and

controlling the amount of light during the emission of at least one of the light having the first wavelength and the light having the second wavelength on the basis of a feedback signal corresponding to the differential signal.