GAS CONCENTRATION CALCULATION DEVICE AND GAS CONCENTRATION MEASUREMENT MODULE

• US 20130003046A1
• Filed: 02/14/2011
• Published: 01/03/2013
• Est. Priority Date: 02/16/2010
• Status: Active Grant

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Izawa, Toshiyuki, Murakami, Tadayoshi
• Granted Patent: US 9,274,048 B2
• Time in Patent Office: Days
• US Class Current: 356/51
• CPC Class Codes: G01N 21/0303 Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment G01N21/031 - G01N21/15 take precedence
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G02B 26/0816 by means of one or more reflecting elements

Abstract

A device includes a gas cell (10X) configured to form an introduction space (11X) into which a target gas is introduced, an infrared light source (20X) disposed at one end of the gas cell (10X), a modulation mirror (70X) disposed at one end of the gas cell (10X) and configured to reflect or transmit light emitted from the infrared light source (20X), a reflecting mirror (60X) configured to reflect light transmitted through the modulation mirror (70X), a saturated gas chamber (40X), in which a predetermined comparison gas is hermetically enclosed, disposed on an optical path of light transmitted through the modulation mirror (70X), a light receiving unit (30X) disposed at the other end of the gas cell (10X) and configured to receive light reflected by the modulation mirror (70X) and light transmitted through the modulation mirror (70X) and reflected by the reflecting mirror (60X) through the saturated gas chamber (40X), and a calculation circuit (3X) configured to calculate the concentration of the target gas based on received light energy values of the light receiving unit (30X) in each case in which light is reflected or transmitted by the modulation mirror (70X).

Claims

1. A gas concentration calculating device including a gas concentration measuring module and a gas concentration calculating module and configured to calculate a concentration of a target gas,

wherein the gas concentration measuring module comprises:

a gas cell configured to form an introduction space into which the target gas is introduced;

a light source disposed at one end of the gas cell;

a reflection switching unit disposed at the one end or the other end of the gas cell to reflect or transmit light emitted from the light source;

a reflecting unit configured to reflect light transmitted through the reflection switching unit;

a comparison gas cell, in which a predetermined comparison gas is hermetically enclosed, disposed on an optical path of light transmitted through the reflection switching unit; and

a light receiving unit disposed at the other end of the gas cell and configured to receive light emitted from the light source and reflected by the reflection switching unit and light emitted from the light source, transmitted through the reflection switching unit, passing through the comparison gas cell and reflected by the reflecting unit, and

wherein the gas concentration calculating module calculates the concentration of the target gas based on received light energy values of the light receiving unit in each case in which light is reflected or transmitted by the reflection switching unit.

2. The gas concentration calculating device according to claim 1, wherein the reflection switching unit is a reflectance modulation unit for electrically modulating a reflectance with respect to light emitted from the light source to switch reflection and transmission of light.

3. The gas concentration calculating device according to claim 2, wherein the reflectance modulation unit is a spatial light modulator.

4. The gas concentration calculating device according to claim 2, wherein the reflectance modulation unit is a liquid crystal optical element.

5. The gas concentration calculating device according to claim 1, wherein the reflection switching unit is a rotary mechanism configured to switch reflection and transmission by rotation with respect to light emitted from the light source.

6. The gas concentration calculating device according to claim 5, wherein the rotary mechanism is a rotating mirror constituted by a reflecting plate and a hole.

7. The gas concentration calculating device according to claim 1, wherein the reflecting unit comprises a plurality of reflecting surfaces having different angles, and sequentially reflects light transmitted through the reflection switching unit at the plurality of reflecting surfaces to allow transmission of the light through the comparison gas cell upon each reflection of the reflecting surfaces.

8. The gas concentration calculating device according to claim 1, wherein the predetermined comparison gas is the same kind of saturated gas as the target gas.

9. The gas concentration calculating device according to claim 1, further comprising a band pass filter disposed on an optical path between the light source and the light receiving unit and configured to transmit light having a predetermined wavelength only.

10. The gas concentration calculating device according to claim 1, wherein the light source emits infrared rays.

11. The gas concentration calculating device according to claim 1, wherein the target gas is carbon dioxide.

12. The gas concentration calculating device according to claim 1, comprising the gas concentration measuring module having a plurality of light receiving unit corresponding to different target gases, and the plurality of gas concentration calculating modules corresponding to the plurality of light receiving unit.

13. A gas concentration measuring module of a gas concentration calculating device configured to calculate a concentration of a target gas, the gas concentration measuring module comprising:

a gas cell configured to form an introduction space into which the target gas is introduced;

a light source disposed at one end of the gas cell;

a reflection switching unit disposed at the one end or the other end of the gas cell to reflect or transmit light emitted from the light source;

a reflecting unit for reflecting light transmitted through the reflection switching unit;

a comparison gas cell, in which a predetermined comparison gas is hermetically enclosed, disposed on an optical path of light transmitted through the reflection switching unit; and

a light receiving unit disposed at the other end of the gas cell, and configured to receive light emitted from the light source and reflected by the reflection switching unit and light emitted from the light source, transmitted through the reflection switching unit, passing through the comparison gas cell and reflected by the reflecting unit.

14. A gas concentration calculating device including a gas concentration measuring module and a gas concentration calculating module and configured to calculate a concentration of a target gas,

wherein the gas concentration measuring module comprises:

a gas cell configured to form an introduction space into which the target gas is introduced;

a light source disposed in the gas cell;

a reflectance modulation unit disposed at one end of the gas cell and configured to electrically modulate a reflectance with respect to light emitted from the light source; and

a light receiving unit disposed at the other end of the gas cell and configured to receive a direct light directly emitted from the light source and a reflection light emitted from the light source and reflected by the reflectance modulation unit, and

wherein the gas concentration calculating module calculates the concentration of the target gas based on a ratio of received light energy values of the light receiving unit in each case in which the reflectance is electrically modulated by the reflectance modulation unit.

15. The gas concentration calculating device according to claim 14, wherein the reflectance modulation unit is an electro-optic device.

16. The gas concentration calculating device according to claim 14, wherein the reflectance modulation unit is a liquid crystal optical element.

17. The gas concentration calculating device according to claim 14, further comprising a band pass filter disposed on an optical path between the light source and the light receiving unit and configured to transmit light having a predetermined wavelength only.

18. The gas concentration calculating device according to claim 14, wherein the light source emits infrared rays.

19. The gas concentration calculating device according to claim 14, wherein the target gas is carbon dioxide.

20. The gas concentration calculating device according to claim 14, further comprising a storage unit for previously storing a database or an approximate equation showing a correlation between the concentration of the target gas and the ratio,

wherein the gas concentration calculating module calculates the concentration corresponding to the ratio based on the database or the approximate equation.

21. The gas concentration calculating device according to claim 14, comprising the gas concentration measuring module having a plurality of light receiving unit corresponding to different target gases, and the plurality of gas concentration calculating modules corresponding to the plurality of light receiving unit.

22. A gas concentration measuring module of a gas concentration calculating device configured to calculate a concentration of a target gas, the gas concentration measuring module comprising:

a gas cell configured to form an introduction space into which the target gas is introduced;

a light source disposed in the gas cell;

a reflectance modulation unit disposed at one end of the gas cell and configured to electrically modulate a reflectance with respect to light emitted from the light source; and

a light receiving unit disposed at the other end of the gas cell and configured to receive a direct light directly emitted from the light source and a reflection light emitted from the light source and reflected by the reflectance modulation unit.

23. A gas concentration calculating device including a gas concentration measuring module and a gas concentration calculating module and configured to calculate a concentration of a target gas,

wherein the gas concentration measuring module comprises:

a gas cell configured to form an introduction space into which the target gas is introduced;

a light source disposed in the gas cell;

a rotary mechanism disposed at one end of the gas cell and configured to reflect or transmit light emitted from the light source by rotation thereof; and

a light receiving unit disposed at the other end of the gas cell and configured to receive a direct light directly emitted from the light source and a reflection light emitted from the light source and reflected by the rotary mechanism, and

wherein the gas concentration calculating module calculates the concentration of the target gas based on a ratio of received light energy values of the light receiving unit in each case in which the light is reflected or transmitted by the rotary mechanism, and

the rotary mechanism performs the rotation in a direction different from a direction of an optical path from the light source to the light receiving unit.

24. The gas concentration calculating device according to claim 23, wherein the rotary mechanism is a rotating mirror constituted by a reflecting plate and a hole.

25. The gas concentration calculating device according to claim 24, wherein the rotating mirror performs the rotation in a direction substantially perpendicular to the direction of the optical path from the light source to the light receiving unit.

26. The gas concentration calculating device according to claim 23, wherein the rotary mechanism is a micro-electro-mechanical system (MEMS) actuator.

27. The gas concentration calculating device according to claim 23, further comprising a band pass filter disposed on an optical path between the light source and the light receiving unit and configured to transmit light having a predetermined wavelength only.

28. The gas concentration calculating device according to claim 23, wherein the light source emits infrared rays.

29. The gas concentration calculating device according to claim 23, wherein the target gas is carbon dioxide.

30. The gas concentration calculating device according to claim 23, further comprising a storage unit for previously storing a database or an approximate equation showing a correlation between the concentration of the target gas and the ratio,

wherein the gas concentration calculating module calculates the concentration corresponding to the ratio based on the database or the approximate equation.

31. The gas concentration calculating device according to claim 23, comprising the gas concentration measuring module having a plurality of light receiving unit corresponding to different target gases, and the plurality of gas concentration calculating modules corresponding to the plurality of light receiving unit.

32. A gas concentration measuring module of a gas concentration calculating device configured to calculate a concentration of a target gas, the gas concentration measuring module comprising:

a gas cell configured to form an introduction space into which the target gas is introduced;

a light source disposed in the gas cell;

a rotary mechanism disposed at one end of the gas cell and configured to reflect or transmit light emitted from the light source by rotation thereof; and

a light receiving unit disposed at the other end of the gas cell and configured to receive a direct light directly emitted from the light source and a reflection light emitted from the light source and reflected by the rotary mechanism,

wherein the rotary mechanism performs the rotation in a direction different from a direction of an optical path from the light source to the light receiving unit.