Gas detection device and control method for gas detection device

Abstract

To provide a gas detection device that can be downsized, and a control method for the gas detection device.SOLUTION: A gas detection device comprises a driver section, an element section, a sensor, and a detector. The driver section includes a first driver and a second driver. The element section includes a first laser and a second laser. The first laser is configured to be driven by the first driver to emit a first beam. A first wavelength of the first beam changes at a first frequency. The second laser is configured to be driven by the second driver to emit a second beam. A second wavelength of the second beam changes at a second frequency. The second frequency is different from the first frequency. The second wavelength is different from the first wavelength. The sensor is configured to detect a received beam based on the first beam and the second beam. The detector is configured to extract a target frequency component from an output signal from the sensor.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a gas detection device and a method for controlling a gas detection device. [Background technology]

[0002] For example, there is a gas detection device that detects a target based on absorption of a laser by the target. Miniaturization of gas detection devices is desirable. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-106521 Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments provide a gas detection device that can be miniaturized and a method for controlling the gas detection device. [Means for solving the problem]

[0005] According to an embodiment, the gas detection device includes a driver section, an element section, a sensor, and a detector. The driver section includes a first driver and a second driver. The element section includes a first laser and a second laser. The first laser is configured to be driven by the first driver to emit a first beam. A first wavelength of the first beam varies at a first frequency. The second laser is configured to be driven by the second driver to emit a second beam. A second wavelength of the second beam varies at a second frequency. The second frequency is different from the first frequency. The second wavelength is different from the first wavelength. The sensor is configured to detect a received beam based on the first beam and the second beam. The detector is configured to extract a target frequency component from an output signal from the sensor. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic view illustrating the gas detection device according to the first embodiment. [Figure 2] FIG. 2 is a schematic view illustrating the gas detection device according to the first embodiment. [Figure 3] FIG. 3 is a flowchart illustrating a control method for the gas detection device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In this specification and in each drawing, elements similar to those previously described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted where appropriate.

[0008] (First embodiment) FIG. 1 is a schematic view illustrating the gas detection device according to the first embodiment. As shown in FIG. 1, a gas detection device 110 according to the embodiment includes a driver section 50, an element section 10, a sensor 41, and a detector 61.

[0009] The driver section 50 includes a first driver 51 and a second driver 52. As will be described later, the driver section 50 may further include other drivers (for example, a third driver 53 and a fourth driver 54).

[0010] The element section 10 includes a first laser 11 and a second laser 12. As will be described later, the element section 10 may further include other lasers (for example, a third laser 13 and a fourth laser 14).

[0011] The first laser 11 is configured to be driven by a first driver 51 to emit a first beam B1. The wavelength (first wavelength) of the first beam B1 changes at a first frequency f1. For example, a first drive signal Sd1 is supplied from the first driver 51 to the first laser 11. The first wavelength is modulated by the first drive signal Sd1.

[0012] The second laser 12 is configured to be driven by a second driver 52 to emit a second beam B2. The wavelength (second wavelength) of the second beam B2 changes at a second frequency f2. For example, a second drive signal Sd2 is supplied from the second driver 52 to the second laser 12. The second wavelength is modulated by the second drive signal Sd2. The second frequency f2 is different from the first frequency f1. The second wavelength (wavelength band) is different from the first wavelength (wavelength band).

[0013] The sensor 41 detects a receiving beam R1 based on the first beam B1 and the second beam B2. The sensor 41 outputs an output signal So1 corresponding to the receiving beam R1. The detector 61 is configured to extract a target frequency component from the output signal So1 from the sensor 41.

[0014] In the example shown in FIG. 1 , the first beam B1 and the second beam B2 pass through a space SP1 along their paths. In this example, these beams are reflected by the reflecting portion 45 and reach the sensor 41 as a received beam R1. A detection target 80 is present in the space SP1. The detection target 80 may be, for example, a gas. The detection target 80 may include molecules such as methane, nitrous oxide, and carbon dioxide, or elements. The detection target 80 has a unique absorption wavelength. By evaluating the intensity of the received beam R1 detected by the sensor 41, the presence or absence of the detection target 80 and / or the concentration of the detection target 80 can be detected. The detection target 80 may include multiple different types of substances (such as a first detection target 81 and a second detection target 82).

[0015] In the embodiment, a beam emitted from a laser is modulated at a specific frequency. A frequency component corresponding to the modulation frequency is extracted by a detector 61, and the intensity of the extracted signal is detected. In the embodiment, a plurality of laser beams (such as a first beam B1 and a second beam B2) having mutually different wavelengths are detected by a single sensor 41. A received beam R1 received by the sensor 41 contains different wavelength components. An output signal So1 corresponding to such a received beam R1 is extracted by the detector 61 as the target frequency component. This allows a single sensor 41 to detect a plurality of types of detection targets 80 with high accuracy.

[0016] For example, a reference example may be considered in which a first sensor is provided corresponding to the first laser 11 and a second sensor is provided corresponding to the second laser 12. In this reference example, the number of sensors increases, which places a limit on how compact the device can be.

[0017] In contrast, in the embodiment, one sensor 41 is provided for a plurality of lasers that emit beams of different wavelengths. The number of sensors 41 can be one. According to the embodiment, a gas detection device that can be made smaller can be provided. According to the embodiment, costs can be reduced. According to the embodiment, a gas detection device that can reduce power consumption can be provided.

[0018] The first wavelength of the first beam B1 is modulated at a first frequency f1 centered on a first intermediate wavelength. For example, the first wavelength varies between a first short wavelength and a first long wavelength at the first frequency f1. The first long wavelength is longer than the first short wavelength. A first intermediate wavelength exists between the first long wavelength and the first short wavelength. For example, the first intermediate wavelength corresponds to the absorption wavelength of the first target substance 81 (first substance). The intensity of the first intermediate wavelength varies depending on whether the first target substance 81 is present or absent. The modulated wavelength of the first beam B1 becomes the first intermediate wavelength twice during one period. Information regarding the presence or absence (and concentration) of the first target substance 81 can be obtained by detecting changes in the component with a frequency twice the first frequency f1. Based on this information, the first target substance 81 can be detected.

[0019] For example, a first intensity of the output signal So1 in the first state is lower than a second intensity of the output signal So1 in the second state. The concentration of the first analyte 81 (such as a first gas) present in the path of the first beam B1 in the first state is higher than a second concentration of the first analyte 81 present in that path in the second state. The first state is a high-concentration state. The second state is a low-concentration state (or a non-existent state). In such a case, due to absorption of the beam, the signal intensity in the first state becomes lower than the signal intensity in the second state.

[0020] For example, the detector 61 may be configured to extract a component (first component) of the output signal So1 that has a frequency twice the first frequency f1. The first component changes depending on the state of the first detection target 81 present in the path (first path) of the first beam B1. The frequency component twice the first frequency f1 in the first state, which is a high-concentration state, is higher than the frequency component twice the first frequency f1 in the second state, which is a low-concentration state.

[0021] For example, the detector 61 may be configured to extract a component (second component) of the output signal So1 having a frequency twice the second frequency f2. The second component changes depending on the state of the second target 82 present in the path (second path) of the second beam B2. The component having a frequency twice the second frequency f2 in the third state, which is a high-concentration state, is higher than the component having a frequency twice the second frequency f2 in the fourth state, which is a low-concentration state. The concentration of the second target 82 (such as the second gas) present in the path of the second beam B2 in the third state is higher than a fourth concentration of the second target 82 present in that path in the fourth state.

[0022] FIG. 2 is a schematic view illustrating the gas detection device according to the first embodiment. 2 illustrates a first beam B1 and a second beam B2. The horizontal axis of FIG. 2 represents time tm. The vertical axis represents the wavelength λ of the beam.

[0023] 2, the first wavelength λ1 of the first beam B1 varies at a first frequency f1 between a first short wavelength λa1 and a first long wavelength λb1. The first long wavelength λb1 is longer than the first short wavelength λa1. A first intermediate wavelength λc1 exists between the first short wavelength λa1 and the first long wavelength λb1.

[0024] As shown in Figure 2, the second wavelength λ2 of the second beam B2 varies at a second frequency f2 between a second short wavelength λa2 and a second long wavelength λb2. The second long wavelength λb2 is longer than the second short wavelength λa2. A second intermediate wavelength λc2 exists between the second short wavelength λa2 and the second long wavelength λb2.

[0025] In one example, the second short wavelength λa2 is longer than the first long wavelength λb1. Or, in an embodiment, the second long wavelength λb2 is shorter than the first short wavelength λa1. In one example, there is substantially no overlap in wavelength between the first beam B1 and the second beam B2. This allows the first detection target 81 to be detected with higher accuracy by the first beam B1. The second detection target 82 can be detected with higher accuracy by the second beam B2.

[0026] In the embodiment, the first beam B1 and the second beam B2 include near infrared rays, mid infrared rays, or far infrared rays, which allows the detection target 80 to be detected with high accuracy.

[0027] For example, the first wavelength λ1 may be 4.4 μm or more and 4.7 μm or less, and the second wavelength λ2 may be 7.6 μm or more and 7.9 μm or less.

[0028] 1, in an embodiment, the driver unit 50 may include a signal generator 58. The signal generator 58 is configured to output a base signal Sb1 having a base frequency f0. The drive signal may be controlled based on the base signal Sb1. The operation of the detector 61 may be controlled based on the base signal Sb1.

[0029] 1, in the embodiment, the driver unit 50 may include a first multiplier 55a and a second multiplier 55b. The first multiplier 55a is configured to supply a first signal S1 having a frequency that is a first integer multiple of the base frequency f0 based on a base signal Sb1 to the first driver 51. The first driver 51 supplies a first drive signal Sd1 based on the first signal S1 to the first laser 11.

[0030] The second multiplier 55b is configured to supply a second signal S2, having a frequency that is a second integer multiple of the base frequency f0, to the second driver 52 based on the base signal Sb1. The second driver 52 supplies a second drive signal Sd2, based on the second signal S2, to the second laser 12. The second integer is different from the first integer. In this example, the first integer is 3. The second integer is 4. By using the reference base frequency f0, the first laser 11 and the second laser 12 can be controlled with high precision.

[0031] In an embodiment, the second frequency f2 may be different from the first frequency f1 by an integer multiple of 2. The first frequency f1 may be different from the second frequency f2 by an integer multiple of 2. Since the harmonics do not overlap, the output signal So1 can be effectively separated.

[0032] In an embodiment, at least a portion of the second period during which the second beam B2 is emitted may overlap with the first period during which the first beam B1 is emitted. These beams may be emitted so as to overlap in time, enabling highly accurate detection in a short period of time.

[0033] For example, a reference example can be considered in which beams of different wavelengths are emitted at different times. In this reference example, the emission time of one beam per unit time becomes short. This reduces the intensity detection of the beam, making it difficult to achieve high accuracy. Alternatively, if sufficient intensity is to be obtained, the detection time becomes long.

[0034] In contrast to this, in the embodiment, a plurality of beams of different wavelengths are emitted so that at least a portion of them overlap in time, enabling highly accurate detection in a short time.

[0035] At least a portion of the second beam B2 may spatially overlap with the first beam B1. For example, even if the size of the sensor 41 is small, the receiving beam R1 can be efficiently incident on the sensor 41. For example, high spatial resolution can be obtained.

[0036] 1, the gas detection device 110 may further include a first optical element 21a. The first optical element 21a overlaps the second beam B2 with the first beam B1. In one example, the first optical element 21a may be a low-pass filter.

[0037] The received beam R1 may include reflected beams of the first beam B1 and the second beam B2. As shown in FIG. 1, the first beam B1 and the second beam B2 may be reflected by a reflecting portion 45 to become the received beam R1. The reflecting portion 45 is, for example, a retroreflector. This enables easier detection. The gas detection device 110 may include the reflecting portion 45. The reflecting portion 45 may be provided separately from the gas detection device 110. In an embodiment, the sensor 41 may detect the first beam B1 and the second beam B2 that have passed through the space SP1 as the received beam R1.

[0038] 1, the gas detection apparatus 110 may include a focusing element 42. The focusing element 42 collects beams (such as the first beam B1 and the second beam B2) that have traveled through the space SP1, enabling efficient detection.

[0039] 1, the gas detection device 110 may include a bandpass filter 43. The bandpass filter 43 transmits a portion of the beam that has passed through the focusing element 42 and attenuates another portion. Unwanted signals are removed, making highly accurate detection easier. The beam that has passed through the bandpass filter 43 is incident on the sensor 41.

[0040] 1, the gas detection device 110 may include a preamplifier 65. The preamplifier 65 amplifies the output signal So1 from the sensor 41. The amplified output signal So1 is provided to the detector 61.

[0041] In one example, the detector 61 may include a lock-in amplifier. For example, as shown in FIG. 1 , a base signal Sb1 having a base frequency f0 (or a signal corresponding to the base signal Sb1) is supplied from the signal generator 58 to the detector 61 as a reference signal. The detector 61 extracts a target signal component using the base frequency f0 or a frequency corresponding to the base frequency f0. The extracted signal component serves as a detection result of the detection target 80.

[0042] 1, the gas detection device 110 may include a control unit 70. The control unit 70 may include, for example, a processing unit 72. The processing unit 72 is configured to process a signal (a signal corresponding to a detection result) obtained from the detector 61. For example, the processing unit 72 may compare the signal obtained from the detector 61 with a reference value to determine the presence or absence of a detection target 80 (gas). The determination result may be output.

[0043] The control unit 70 may include a driver control unit 71. The driver control unit 71 is configured to control a plurality of drivers (such as a first driver 51 and a second driver 52). For example, based on the output of the first multiplier 55a and the control of the driver control unit 71, the first driver 51 supplies a first drive signal Sd1 to the first laser 11. For example, based on the output of the second multiplier 55b and the control of the driver control unit 71, the second driver 52 supplies a second drive signal Sd2 to the second laser 12.

[0044] 1, the gas detection device 110 may further include a visible light laser 18. The visible light laser 18 emits a visible light beam B8. The visible light beam B8 is emitted toward the space SP1, for example, together with the first beam B1 and the second beam B2. The visible light beam B8 is used, for example, as a target laser.

[0045] As shown in FIG. 1 , the driver section 50 may further include a third driver 53. The element section 10 may further include a third laser 13. The third laser 13 is configured to be driven by the third driver 53 to emit a third beam B3. The third wavelength of the third beam B3 varies at a third frequency f3. The third wavelength is different from the first wavelength λ1 and different from the second wavelength λ2. The third frequency f3 is different from the first frequency f1 and different from the second frequency f2. The receiving beam R1 is further based on the third beam B3. The detector 61 is configured to further extract a third component of the output signal So1, for example, at a frequency twice the third frequency f3.

[0046] 1, the gas detection device 110 may further include a second optical element 21b. The second optical element 21b overlaps the third beam B3 with the first beam B1. In one example, the second optical element 21b may be a low-pass filter.

[0047] As already described, the first multiplier 55a is configured to supply the first driver 51 with a first signal S1 having a frequency that is a first integer multiple of the base frequency f0 based on the base signal Sb1. The second multiplier 55b is configured to supply the second driver 52 with a second signal S2 having a frequency that is a second integer multiple of the base frequency f0 based on the base signal Sb1.

[0048] As shown in FIG. 1 , the driver section 50 may further include a third multiplier 55c. The third multiplier 55c is configured to supply a third signal S3 having a frequency that is a third integer multiple of the base frequency f0 to the third driver 53 based on the base signal Sb1. The second integer is different from the first integer. The third integer is different from the first integer and different from the second integer. In this example, the first integer is 3. The second integer is 4. The third integer is a prime number greater than or equal to 5. The third integer may be 5.

[0049] The first driver 51 supplies a first drive signal Sd1 based on the first signal S1 to the first laser 11. The second driver 52 supplies a second drive signal Sd2 based on the second signal S2 to the second laser 12. The third driver 53 supplies a third drive signal Sd3 based on the third signal S3 to the third laser 13. A third detection object 83 is detected by a third beam B3 of the third laser 13.

[0050] As shown in FIG. 1, the driver unit 50 may further include a fourth driver 54. The element unit 10 may further include a fourth laser 14. The fourth laser 14 is configured to be driven by the fourth driver 54 to emit a fourth beam B4. The fourth wavelength of the fourth beam B4 varies at a fourth frequency f4. The fourth wavelength is different from the first wavelength λ1, different from the second wavelength λ2, and different from the third wavelength. The fourth frequency f4 is different from the first frequency f1, different from the second frequency f2, and different from the third frequency f3. The receiving beam R1 is further based on the fourth beam B4. The detector 61 is configured to further extract a fourth component of the output signal So1, for example, at a frequency twice the fourth frequency f4. A fourth detection target 84 can be detected by the fourth beam B4.

[0051] 1, the gas detection device 110 may further include a third optical element 21c. The third optical element 21c overlaps the fourth beam B4 with the first beam B1. In one example, the third optical element 21c may be a low-pass filter.

[0052] 1, the driver section 50 may further include a fourth multiplier 55d. The fourth multiplier 55d is configured to supply a fourth signal S4, having a frequency that is a fourth integer multiple of the base frequency f0, to the fourth driver 54 based on the base signal Sb1. The fourth driver 54 supplies a fourth drive signal Sd4 based on the fourth signal S4 to the fourth laser 14. The fourth integer is different from the first integer, different from the second integer, and different from the third integer. For example, the first integer may be 3, the second integer may be 4, the third integer may be 5, and the fourth integer may be 7.

[0053] In the embodiment, the laser included in the element portion 10 may be, for example, a quantum cascade laser (QCL). For example, at least one of the first laser 11, the second laser 12, the third laser 13, and the fourth laser 14 may be a QCL. The laser included in the element portion 10 may include, for example, a photonic crystal layer. The laser included in the element portion 10 may be, for example, a surface-emitting type. The laser included in the element portion 10 may be, for example, an edge-emitting type.

[0054] (Second embodiment) The second embodiment relates to a method for controlling the gas detection device 110. FIG. 3 is a flowchart illustrating a control method for the gas detection device according to the second embodiment. 3, for example, the element unit 10 is caused to emit laser beams (for example, a first beam B1 and a second beam B2) (step S101). For example, the received beam R1 is detected (step S105). Step S105 is performed by, for example, the sensor 41.

[0055] 3, a first intensity A1 of the component of the first frequency f1 and a second intensity A2 of the component of the frequency twice the first frequency f1 are derived from the detection result of the received beam R1 (step S110). Step S110 is performed by, for example, the detector 61 and the processing unit 72.

[0056] 3, the first intensity A1 is compared with a first reference value v1 (step S120). When the first intensity A1 is higher than the first reference value v1, the process proceeds to step S130. In step S130, the ratio of the second intensity A2 to the first intensity A1 is compared with a second reference value v2. When the ratio is higher than the second reference value v2, a first output is output (step S141).

[0057] The first output may be, for example, information corresponding to the ratio of the second intensity A2 to the first intensity A1. The first output may be, for example, information indicating that the ratio is higher than a second reference value v2. The first output may be, for example, information indicating the presence of the first detection target 81.

[0058] If the ratio is equal to or less than the second reference value v2 in step S130, the first output is not output. For example, if the ratio is equal to or less than the second reference value v2, the second output is output (step S142). The second output may be, for example, information indicating that the ratio is equal to or less than the second reference value v2. The second output may be, for example, information indicating that the first detection target 81 is not present.

[0059] In step S120, if the first intensity A1 is equal to or less than the first reference value v1, the process may return to step S110, step S105, or step S101. In this case, for example, in step S101, at least one of the multiple lasers may be stopped and the other lasers may be operated. In this state, measurements (steps S105 and onward) may be performed.

[0060] In the above step S120, if the first intensity A1 is equal to or less than the first reference value v1, the operation of the visible light laser 18 may be stopped and another laser may be operated. In this state, measurements (steps S105 and onward) may be performed.

[0061] In this way, when the first intensity A1 of the component of the first frequency f1 of the output signal So1 is higher than the first reference value v1, the gas detection device 110 is caused to perform a first operation. The first operation includes outputting a value corresponding to the ratio of the second intensity A2 of the component of the output signal So1 having a frequency twice the first frequency f1 to the first intensity A1. This value may be, for example, the ratio of the second intensity A2 to the first intensity A1. The first operation includes, for example, outputting a first output. High-precision measurements can be performed.

[0062] In the control method according to the embodiment, when the first intensity A1 is equal to or less than the first reference value v1, the gas detection device 110 is not caused to perform the first operation. For example, as described above, the measurement (step S105 and subsequent steps) may be performed again with at least one of the multiple lasers stopped. For example, as described above, the operation of the visible light laser 18 may be stopped and the measurement (step S105 and subsequent steps) may be performed again. This allows for highly accurate measurements.

[0063] The embodiments may include the following technical solutions. (Technical proposal 1) a driver unit including a first driver and a second driver; An element portion including a first laser and a second laser, the first laser is configured to be driven by the first driver to emit a first beam, a first wavelength of the first beam varying at a first frequency; the second laser is configured to be driven by the second driver to emit a second beam, a second wavelength of the second beam varying at a second frequency, the second frequency being different from the first frequency, and the second wavelength being different from the first wavelength; the element portion; a sensor configured to detect a receive beam based on the first beam and the second beam; a detector configured to extract a frequency component of interest from the output signal from the sensor; A gas detection device comprising:

[0064] (Technical proposal 2) the first wavelength varies between a first short wavelength and a first long wavelength at the first frequency; the first long wavelength is longer than the first short wavelength; the second wavelength varies between a second shorter wavelength and a second longer wavelength at the second frequency; the second long wavelength is longer than the second short wavelength; The gas detection device according to Technical Solution 1, wherein the second short wavelength is longer than the first long wavelength, or the second long wavelength is shorter than the first short wavelength.

[0065] (Technical proposal 3) The driver unit a signal generator configured to output a base signal having a base frequency; a first multiplier configured to provide the first driver with a first signal having a frequency that is a first integer multiple of the base frequency based on the base signal; a second multiplier configured to provide the second driver with a second signal having a frequency that is a second integer multiple of the base frequency based on the base signal; Including, The gas detection device according to Technical Solution 1, wherein the second integer is different from the first integer.

[0066] (Technical proposal 4) the first integer is 3; The gas detection device according to Technical Solution 3, wherein the second integer is 4.

[0067] (Technical proposal 5) the second frequency is different from an integer multiple of twice the first frequency, The gas detection device according to any one of Technical Schemes 1 to 4, wherein the first frequency is different from an integral multiple of twice the second frequency.

[0068] (Technical proposal 6) The gas detection device according to any one of Technical Schemes 1 to 5, wherein the first beam and the second beam include near infrared rays, mid infrared rays, or far infrared rays.

[0069] (Technical proposal 7) the first wavelength is equal to or greater than 4.4 μm and equal to or less than 4.7 μm, The gas detection device according to any one of Technical Schemes 1 to 6, wherein the second wavelength is not less than 7.6 μm and not more than 7.9 μm.

[0070] (Technical proposal 8) a first magnitude of the output signal in the first state being lower than a second magnitude of the output signal in the second state; A gas detection device described in any one of Technical Solutions 1 to 7, wherein the concentration of a first detection target present in the path of the first beam in the first state is higher than a second concentration of the first detection target present in the path in the second state.

[0071] (Technical proposal 9) the detector is configured to extract a first component of the output signal at twice the first frequency; The gas detection device according to Technical Solution 1, wherein the detector is configured to extract a second component of the output signal at a frequency twice the second frequency.

[0072] (Technical proposal 10) the first component changes depending on a state of a first detection target present on a first path of the first beam; A gas detection device as described in Technical Solution 9, wherein the second component changes depending on the state of a second detection target present in the second path of the second beam.

[0073] (Technical proposal 11) 11. The gas detection device according to any one of Technical Solutions 1 to 10, wherein at least a portion of the second period during which the second beam is emitted overlaps with the first period during which the first beam is emitted.

[0074] (Technical proposal 12) 12. The gas detection device according to any one of Technical Schemes 1 to 11, wherein at least a portion of the second beam spatially overlaps with the first beam.

[0075] (Technical proposal 13) The gas detection device according to any one of Technical Schemes 1 to 12, further comprising a first optical element that causes the second beam to overlap the first beam.

[0076] (Technical proposal 14) The gas detection device according to any one of Technical Schemes 1 to 13, wherein the received beam includes reflected beams of the first beam and the second beam.

[0077] (Technical proposal 15) the driver section further includes a third driver; the element portion further includes a third laser, the third laser is configured to be driven by the third driver to emit a third beam; a third wavelength of the third beam varying at a third frequency; the third wavelength is different from the first wavelength and different from the second wavelength; the third frequency is different from the first frequency and different from the second frequency; the receive beam is further based on the third beam; The gas detection device according to Technical Solution 9, wherein the detector is configured to further extract a third component of the output signal at a frequency twice the third frequency.

[0078] (Technical proposal 16) The driver unit a signal generator configured to output a base signal having a base frequency; a first multiplier configured to provide the first driver with a first signal having a frequency that is a first integer multiple of the base frequency based on the base signal; a second multiplier configured to provide the second driver with a second signal having a frequency that is a second integer multiple of the base frequency based on the base signal; a third multiplier configured to provide the third driver with a third signal having a frequency that is a third integer multiple of the base frequency based on the base signal; Including, the second integer is different from the first integer; the third integer is different from the first integer and different from the second integer; the first driver supplies a first drive signal based on the first signal to the first laser; the second driver supplies a second drive signal based on the second signal to the second laser; The gas detection device according to Technical Proposal 15, wherein the third driver supplies a third drive signal based on the third signal to the third laser.

[0079] (Technical proposal 17) the first integer is 3; the second integer is 4; The gas detection device according to Technical Solution 16, wherein the third integer is a prime number greater than or equal to 5.

[0080] (Technical proposal 18) the driver section further includes a fourth driver; the element portion further includes a fourth laser, the fourth laser is configured to be driven by the fourth driver to emit a fourth beam; a fourth wavelength of the fourth beam varying at a fourth frequency; the fourth wavelength is different from the first wavelength, different from the second wavelength, and different from the third wavelength; the fourth frequency is different from the first frequency, different from the second frequency, and different from the third frequency; the receive beam is further based on the fourth beam; The gas detection device according to Technical Solution 16, wherein the detector is configured to further extract a fourth component of the output signal having a frequency twice the fourth frequency.

[0081] (Technical proposal 19) the driver section further includes a fourth multiplier; the fourth multiplier is configured to supply a fourth signal having a frequency that is a fourth integer multiple of the base frequency to the fourth driver based on the base signal; Including, The gas detection device according to Technical Solution 18, wherein the fourth integer is different from the first integer, different from the second integer, and different from the third integer.

[0082] (Technical proposal 20) In the gas detection device described in Technical Proposal 9, causing the gas detection device to execute a first operation of outputting a value according to a ratio of a second intensity of a component of the output signal having a frequency twice the first frequency to the first intensity when a first intensity of the component of the output signal having the first frequency is higher than a first reference value; A control method for a gas detection device, the method including causing the gas detection device not to perform the first operation when the first intensity is equal to or less than the first reference value.

[0083] According to the embodiments, it is possible to provide a gas detection device that can be miniaturized and a method for controlling a gas detection device.

[0084] The above describes embodiments of the present invention with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configurations of each element included in the gas detection device, such as the driver section, element section, laser, driver, multiplier, sensor, and detector, are within the scope of the present invention as long as a person skilled in the art can implement the present invention in a similar manner and obtain similar effects by appropriately selecting them from within the known range.

[0085] Furthermore, any combination of two or more elements of each specific example within the scope of technical feasibility is also included within the scope of the present invention as long as it includes the gist of the present invention.

[0086] In addition, all gas detection devices and gas detection device control methods that can be implemented by a person skilled in the art by making appropriate design modifications based on the gas detection device and gas detection device control method described above as embodiments of the present invention also fall within the scope of the present invention, as long as they include the gist of the present invention.

[0087] In addition, within the scope of the concept of the present invention, a person skilled in the art may come up with various modifications and alterations, and it will be understood that these modifications and alterations also fall within the scope of the present invention.

[0088] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0089] 10: element section, 11-14: first to fourth lasers, 18: visible light laser, 21a-21c: first to third optical elements, 41: sensor, 42: focusing element, 43: bandpass filter, 45: reflecting section, 50: driver section, 51-54: first to fourth drivers, 55a-55d: first to fourth multipliers, 58: signal generator, 61: detector, 65: preamplifier, 70: control section, 71: driver control section, 72: processing section, 80: detection object, 81-84: first to fourth detection objects, 110: gas detection device, B1-B4: first to fourth beams, B8: visible light beam, R1: received beam, S1-S4: first to fourth signals, SP1: space, Sb1: base signal, Sd1 to Sd4: 1st to 4th drive signals, So1: output signal, f1, f2: 1st and 2nd frequencies, v1, v2: 1st and 2nd reference values, λ: wavelength, λ1, λ2: 1st and 2nd wavelengths, λa1, λa2: 1st and 2nd short wavelengths, λb1, λb2: 1st and 2nd long wavelengths, λc1, λc2: 1st and 2nd intermediate wavelengths

Claims

1. a driver unit including a first driver and a second driver; An element portion including a first laser and a second laser, the first laser is configured to be driven by the first driver to emit a first beam, a first wavelength of the first beam varying at a first frequency; the second laser is configured to be driven by the second driver to emit a second beam, a second wavelength of the second beam varying at a second frequency, the second frequency being different from the first frequency, and the second wavelength being different from the first wavelength; the element portion; a sensor configured to detect a receive beam based on the first beam and the second beam; a detector configured to extract a frequency component of interest from the output signal from the sensor; A gas detection device comprising:

2. the first wavelength varies at the first frequency between a first short wavelength and a first long wavelength; the first long wavelength is longer than the first short wavelength; the second wavelength varies between a second shorter wavelength and a second longer wavelength at the second frequency; the second long wavelength is longer than the second short wavelength; 2. The gas detection device according to claim 1, wherein the second short wavelength is longer than the first long wavelength, or the second long wavelength is shorter than the first short wavelength.

3. The driver unit a signal generator configured to output a base signal having a base frequency; a first multiplier configured to provide the first driver with a first signal having a frequency that is a first integer multiple of the base frequency based on the base signal; a second multiplier configured to provide the second driver with a second signal having a frequency that is a second integer multiple of the base frequency based on the base signal; Including, The gas detection apparatus of claim 1 , wherein the second integer is different from the first integer.

4. the detector is configured to extract a first component of the output signal at twice the first frequency; 2. The gas detection apparatus of claim 1, wherein the detector is configured to extract a second component of the output signal at twice the second frequency.

5. the first component changes depending on a state of a first detection target present on a first path of the first beam; 5. The gas detection device according to claim 4, wherein the second component changes depending on the state of a second detection target present in the second path of the second beam.

6. the driver section further includes a third driver; the element portion further includes a third laser, the third laser is configured to be driven by the third driver to emit a third beam; a third wavelength of the third beam varying at a third frequency; the third wavelength is different from the first wavelength and different from the second wavelength; the third frequency is different from the first frequency and different from the second frequency; the receive beam is further based on the third beam; 5. The gas detection apparatus of claim 4, wherein the detector is further configured to extract a third component of the output signal at a frequency twice the third frequency.

7. The driver unit a signal generator configured to output a base signal having a base frequency; a first multiplier configured to provide the first driver with a first signal having a frequency that is a first integer multiple of the base frequency based on the base signal; a second multiplier configured to provide the second driver with a second signal having a frequency that is a second integer multiple of the base frequency based on the base signal; a third multiplier configured to provide the third driver with a third signal having a frequency that is a third integer multiple of the base frequency based on the base signal; Including, the second integer is different from the first integer; the third integer is different from the first integer and different from the second integer; the first driver supplies a first drive signal based on the first signal to the first laser; the second driver supplies a second drive signal based on the second signal to the second laser; 7. The gas detection device according to claim 6, wherein the third driver supplies the third laser with a third drive signal based on the third signal.

8. the first integer is 3; the second integer is 4; 8. The gas detection device according to claim 7, wherein the third integer is a prime number greater than or equal to five.

9. 5. The gas detection device according to claim 4, causing the gas detection device to execute a first operation of outputting a value according to a ratio of a second intensity of a component of the output signal having a frequency twice the first frequency to the first intensity when a first intensity of the component of the output signal having the first frequency is higher than a first reference value; A control method for a gas detection device, the method including causing the gas detection device not to perform the first operation when the first intensity is equal to or less than the first reference value.

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