Gas analysis device and gas analysis method

Abstract

A gas analysis device (10) includes a laser light source (11) that irradiates laser light to a measurement target gas, a laser controller (14) that controls the laser light source (11) in such a manner that wavelengths of the laser light each vary within a prescribed wavelength band, a light detector (19) that photoelectrically converts laser light transmitted through the measurement target gas and outputs an electric signal, and an analysis section (23) that analyzes an absorption wavelength of the measurement target gas based on the electric signal. In the gas analysis device (10), the laser controller (14) controls the laser light source (11) so that an intensity of the laser light varies in a shape having at least a substantially constant flat portion (for example, a rectangular shape or a trapezoidal shape) within a prescribed time period, and the wavelength of the laser light varies within the time period.

Description

TECHNICAL FIELD

[0001] The present application relates to a gas analysis device and a gas analysis method for analyzing a target gas using a laser. BACKGROUND

[0002] In recent years, from the viewpoint of preventing global warming, depletion of fossil fuels, environmental pollution, and the like, earth environmental protection and efficient use of energy are attracting attention in various fields, and various environmental technologies are being researched.

[0003] In such environmental technologies, it is important to elucidate the combustion structure of combustion phenomena in engines or combustors and the like in detail, and their transient behavior. In recent years, as a device for measuring the distribution of temperature or concentration in a combustion gas with high response and in time series, a measurement technique using a semiconductor laser absorption method has been developed.

[0004] Generally, the absorption method is a measurement method that utilizes the property of a gas molecule to absorb infrared rays of a wavelength specific to a chemical species, and the temperature dependence and concentration dependence of the amount of absorption. By finding the ratio (I λ0 / I λ ) of the intensity (I λ ) of incident light to the intensity (I λ0 ) of transmitted light when the incident light passes through an absorption medium (target gas) having the same optical path length, the concentration or temperature of the target gas can be measured (for example, refer to Non-Patent Documents 1 and 2). In particular, a method for analyzing a target gas using a phenomenon in which a laser of a prescribed wavelength is absorbed using a variable wavelength semiconductor laser is called wavelength variable semiconductor laser absorption spectroscopy (TDLAS: TUNABLE DIODE LASER ABSORPTION SPECTROSCOPY).

[0005] Technologies for detecting the properties (concentration or temperature) of a measurement target gas using an absorption method using a semiconductor laser are disclosed in Patent Documents 1 to 3 and the like.

[0006] For example, in Patent Document 1, a method is disclosed in which a laser is split into a measurement laser and a reference laser with a splitter, the measurement laser is transmitted through a gas and received with a photodetector, and the absorption spectrum absorbed by a gas component in the gas is grasped from the light intensity of the received measurement laser and the light intensity of the reference laser.

[0007] In addition, in Patent Literature 2, there is disclosed a method in which, when an oscillation wavelength of laser light is modulated with a modulation signal of a prescribed frequency, there are a first period in which an absorption wavelength inherent to a gas-like substance to be measured is modulated with the prescribed frequency and a second period in which a wavelength deviating from the inherent absorption wavelength is modulated with the prescribed frequency, and an accurate gas concentration is obtained by subtracting a bias signal measured in the second period from a gas concentration signal including a bias signal measured in the first period.

[0008] Further, in Patent Literature 3, a gas analysis device includes first and second laser light sources that output first and second laser lights, a laser control section that controls the first and second laser light sources so that the wavelengths of the first and second laser lights each vary within a prescribed wavelength band, a combining section that mixes the first and second laser lights and irradiates a measurement target gas, a light receiving section that receives laser light transmitted through the measurement target gas, and an analysis section that analyzes a temperature and / or a concentration of the measurement target gas based on an electric signal from the light receiving section. Here, the laser control section makes the magnitude of the amplitude of the first laser light different from the magnitude of the amplitude of the second laser light and makes the intensity of the first laser light and the intensity of the second laser light vary in opposite directions when causing the wavelengths of the laser lights to vary.

[0009] Prior Art Documents

[0010] Patent Literature

[0011] Patent Literature 1: Japanese Patent Application Publication No. 2008-051598

[0012] Patent Literature 2: Japanese Patent Application Publication No. 2011-158426

[0013] Patent Literature 3: Japanese Patent Application Publication No. 2015-040747

[0014] Non-Patent Literature

[0015] Non-Patent Literature 1: Maximilian Lackner, "TUNABLE DIODE LASER ABSORPTION SPECTROSCOPY (TDLAS) IN THE PROCESS INDUSTRIES - A REVIEW," Reviews in Chemical Engineering, Vol. 23, Issue 2, April 2007.

[0016] Non-Patent Literature 2: Akiteru Murata, "Introduction of Process Laser Gas Analyzer," Environment, Japan Environmental Technology Association, pp. 18-19, January 2010 SUMMARY

[0017] PROBLEMS TO BE SOLVED BY THE INVENTION

[0018] In the technologies disclosed in Patent Documents 1 to 3, the influence of the reduction in laser intensity caused by contamination of a window provided in the optical path, etc. cannot be eliminated. Specifically, when a measurement target gas is measured based on an absorption spectrum, it is important to detect the position (wavelength) and size of a portion in which the signal intensity appearing in the absorption spectrum is reduced (hereinafter also referred to as "absorption line"). There is a case where the laser irradiated on the measurement target gas is varied due to a factor other than the original absorption of the window provided in the optical path of the laser, etc. In such a case, there is a problem that the size of the portion in which the signal intensity appearing in the absorption spectrum is reduced (absorption line) is different from that in the case of the original absorption, and the analysis accuracy of the gas is reduced.

[0019] In particular, in Patent Document 3, there is a problem that high sensitivity and high accuracy become difficult due to a slight variation in the mixed signal.

[0020] An object of the present application is to provide a gas analysis device and a gas analysis method capable of analyzing a gas with high accuracy compared to the related art.

[0021] Solution to the problem

[0022] The gas analysis device in the present application includes:

[0023] a laser light source that irradiates a laser light on a measurement target gas;

[0024] a laser controller that controls the laser light source so that the wavelengths of the laser lights each vary within a prescribed wavelength band;

[0025] a light detector that photoelectrically converts the laser light transmitted through the measurement target gas and outputs an electric signal; and

[0026] an analysis section that analyzes an absorption wavelength of the measurement target gas based on the electric signal,

[0027] wherein the laser controller controls the laser light source so that the intensity of the laser light varies within a prescribed time period in a shape having at least a substantially constant flat portion, and the wavelength of the laser light varies within the time period.

[0028] Effects of the Invention

[0029] Therefore, according to the present application, the laser controller controls the laser light source so that the intensity of the laser light varies within a prescribed time period in a shape having at least a substantially constant flat portion, and the wavelength of the laser light varies within the time period. Thus, the detection accuracy of gas analysis can be improved compared to the related art. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1A is a block diagram showing a structure example of the gas analyzing apparatus 10 in Embodiment 1.

[0031] Figure 1B is a block diagram showing details of the laser controller 14 and the laser 11 of Figure 1A .

[0032] Figure 2 is a block diagram showing details of the gas analyzing apparatus 10 of Figure 1A .

[0033] Figure 3 is a block diagram showing a structure example of the gas analyzing apparatus 10A in Embodiment 2.

[0034] Figure 4 is a block diagram showing details of the gas analyzing apparatus 10A of Figure 3 .

[0035] Figure 5 is a block diagram showing a structure example of the gas analyzing apparatus 10B in Embodiment 3.

[0036] Figure 6 is a waveform chart showing the intensity of the laser 1 in the modified example of Embodiments 1 to 3.

[0037] Figure 7 is an absorption spectrum chart showing the wavelength characteristics of the absorbance when the target gas in the gas analyzing apparatuses 10, 10A, 10B in Embodiments 1 to 3 is H2O.

[0038] Figure 8 is a waveform chart of the output voltage of the photodetector 19 when the target gas is H2O and the chamber pressure is 100 Torr, which is an experimental result of the embodiment of the gas analyzing apparatus 10 in Embodiment 1.

[0039] Figure 9 is a waveform chart of the output voltage of the photodetector 19 when the target gas is H2O and the chamber pressure is 50 Torr, which is an experimental result of the embodiment of the gas analyzing apparatus 10 in Embodiment 1.

[0040] Figure 10 is a waveform chart of the output voltage of the photodetector 19 when the target gas is H2O and the chamber pressure is 10 Torr, which is an experimental result of the embodiment of the gas analyzing apparatus 10 in Embodiment 1.

[0041] Figure 11 This is a block diagram showing a structural example of the two-dimensional gas analysis device 10C in Embodiment 4.

[0042] Figure 12 It is shown Figure 11 A schematic diagram of the application example 1 of the two-dimensional gas analyzer 10C in the burner 100.

[0043] Figure 13 It is shown Figure 11 A schematic diagram of the application example 2 of the two-dimensional gas analysis device 10C in engine 200.

[0044] Figure 14 It is shown Figure 11 A schematic diagram of the application of the two-dimensional gas analyzer 10C in a jet engine 300, Example 3.

[0045] Figure 15 It is shown Figure 11 Example 4 shows a schematic diagram of the application of the two-dimensional gas analyzer 10C in semiconductor processing.

[0046] Figure 16 It is shown Figure 15 The flowchart of application example 4.

[0047] Figure 17 It is shown Figure 11 Example 5: Schematic diagram of the application of the two-dimensional gas analyzer 10C in the denitrification unit 400.

[0048] Figure 18 It is shown Figure 11 The flowchart of Example 6 shows the application of the two-dimensional gas analyzer 10C in the exhaust gas denitrification system 500.

[0049] Figure 19 This is the experimental result of Example 1 of the gas analysis device 10 in Embodiment 1, showing the waveform of the output voltage of the photodetector 19 when the target gas is H2O and the chamber pressure is 10 Torr (1.3 kPa).

[0050] Figure 20 This is the experimental result of Example 2 of the gas analysis device 10A in Embodiment 2, showing the waveform of the output voltage of the photodetector 19 when the target gas is H2O and the chamber pressure is 10 Torr (1.3 kPa).

[0051] Figure 21 The experimental results of Embodiment 2 of the gas analysis device 10A in Embodiment 2 are shown in the waveform diagram of the output voltage of the photodetector 19, which can improve the amplification of the AC signal. Detailed Implementation

[0052] Embodiments of the present application will be described below with reference to the accompanying drawings. Note that the same or similar structures are denoted by the same reference numerals throughout the drawings.

[0053] Features of Embodiments

[0054] In the embodiments and modified examples of the present application, a measurement target gas is analyzed and measured by using a variable wavelength distribution active distribution feedback (TDFB) type semiconductor laser, and the concentration and temperature are detected by a TDLAS method. Here, in the present embodiment, particularly as described later, for example, it is characterized in that a laser light source is controlled so that the intensity of laser light is varied in a shape having at least a substantially constant flat portion (for example, a rectangular shape or a trapezoidal shape) during a prescribed time period, and the wavelength of the laser light is varied during the time period.

[0055] Embodiment 1

[0056] Structure of gas analysis device

[0057] Figure 1A is a block diagram showing a structure example of the gas analysis device 10 in Embodiment 1, Figure 1B is a block diagram showing details of the laser controller 14 and the laser 11 of Figure 1A . In addition, Figure 2 is a graph showing the operation of the gas analysis device 10 of Figure 1A is a graph showing the operation of the gas analysis device 10 of

[0058] In the gas analysis device 10 in Figure 1A , the gas analysis device 10 includes a semiconductor laser (hereinafter referred to as a laser) 11 as a laser light source, a laser controller 14, a collimator 17, a photodetector 19, an AC amplifier 21 that amplifies an electric signal Sd from the photodetector 19, and an analysis device 23. Note that, as described later in detail, the AC amplifier 21 is not limited to an AC amplifier, but is an amplifier that can amplify based on a portion where the intensity of laser light is constant.

[0059] In the gas analysis device 10 in Figure 1BIn this configuration, the laser control device 14 includes a controller 60, a waveform generator 61, and a current power supply 62. The controller 60 controls the waveform generator 61 to set the period, duty cycle, voltage, etc., of the voltage signal generated by the waveform generator 61. In response, the waveform generator 61 generates a predetermined voltage signal having a shape such as a rectangular wave or a trapezoidal wave and outputs it to the current power supply 62. The current power supply 62 includes a voltage-to-current conversion circuit that converts the input voltage signal into a predetermined drive current having a shape such as a rectangular wave or a trapezoidal wave and flowing between a pair of electrodes 41, 42 of the laser 11.

[0060] In addition, Figure 1B In this configuration, the laser 11 is formed by sandwiching a p-type cladding layer 43, an active layer 44, an n-type cladding layer 45, and an n-type substrate 46 between a pair of electrodes 41 and 42, and a reflective surface 51 is formed on one side. In response to a current flowing through the pair of electrodes 41 and 42, the active layer 44 generates laser light, and the laser light reflected by the reflective surface 51 travels along... Figure 1B It is emitted laterally.

[0061] That is, laser 11 is a laser source capable of outputting laser light 1 in a specified wavelength band. In this embodiment, laser 11 is a known variable wavelength distribution active distributed feedback (TDFB) semiconductor laser, and lasers 12 and 13 described later are the same. Generally, a TDFB laser can output laser light of a specified intensity by being input with an excitation current exceeding a threshold current. Here, under the action of the driving current, the current value flowing through laser 11 changes in shape, for example, a rectangular wave or a trapezoidal wave, causing a change in the laser output, and at this time, a change in the temperature of laser 11. As a result, due to the change in the diffraction grating spacing inside laser 11, the wavelength of the laser light changes.

[0062] In this embodiment, the laser control device 14 changes the excitation current value for the laser 11 synchronously with a clock signal of a predetermined frequency, such as... Figure 2 As shown, the intensity of laser 1 is varied in a rectangular pulse shape with a duty cycle of, for example, 50% (time period T1 = T2). By controlling laser 11 in this way, the intensity of laser 1 is approximately constant within time period T1 at the maximum intensity E1 of the rectangular pulse, having a flat portion Lf1. Here, preferably, for example, to achieve high accuracy for moisture detection in the semiconductor process apparatus described later, the intensity variation of the flat portion Lf1 is set relative to the maximum intensity E1, for example, at a threshold value of 10. -6 the following.

[0063] At this time, the wavelength of the laser light 1 is slightly delayed from the rise of the light intensity, and changes monotonously in proportion to time within a wavelength scan range Lwl from a wavelength λl to a wavelength λ2 as the temperature of the laser 11 rises. That is, the laser control device 14 can control the laser 11 to output the laser light 1 from the laser 11 while changing (scanning) the wavelength of the laser light 1 with time.

[0064] Note that, in the illustration of the wavelength of the laser light 1, the broken line indicates that the wavelength of the laser light 1 is not determined and is uncertain, which is also applicable to the wavelength of the laser light 1 described later. Figure 2 In the illustration of the wavelength of the laser light 1, the broken line indicates that the wavelength of the laser light 1 is not determined and is uncertain, which is also applicable to the wavelength of the laser light 1 described later. Figure 4 Here, by setting the absorption wavelength of the measurement target gas between the wavelengths λl and λ2, a falling portion Ldl of the output voltage of the electric signal Sd from the photodetector 19 is generated in a prescribed wavelength λa.

[0065] The laser light 1 from the laser 11 is input to the photodetector 19 after being irradiated to the measurement target gas via the collimator 17 that makes the laser light 1 parallel and focuses it. The photodetector 19 receives the laser light transmitted through the measurement target gas and photoelectrically converts it into an analog electric signal Sd that includes an alternating current component according to the intensity of the received laser light. The AC amplifier 21 has an amplification band that can sufficiently amplify the alternating current component of the electric signal Sd (particularly, since the intensity of the laser light 1 sharply rises or falls, it has a high harmonic component), and is an amplifier that can amplify with a portion of the flat portion where the intensity of the laser light is constant as a reference. Particularly, the AC amplifier 21 is configured to, for example, apply a prescribed bias to the electric signal Sd so as to be located at Figure 2 the falling portion Ldl of the output voltage of the electric signal Sd. The AC amplifier 21 amplifies the analog electric signal Sd from the photodetector 19 as described above, and outputs the amplified electric signal Sda to the analysis device 23. Next, the analysis device 23 inputs the analog electric signal Sda from the AC amplifier 21 and AD-converts it by a built-in AD converter, and analyzes the waveform (absorption spectrum) of the electric signal Sda as known, and analyzes the concentration and temperature of the measurement target gas (for example, refer to Non-Patent Documents 1 and 2). The analysis device 23 can be realized by, for example, a computer (information processing device).

[0066] In the gas analysis apparatus 10 configured as described above, for example, the target gas is irradiated with laser 1 while scanning the wavelength of laser 1 output by laser 11 within a predetermined wavelength band of λ1 to λ2, which includes the estimated absorption wavelength λa. At this time, the concentration or temperature of the target gas is measured by analyzing the absorption spectrum of the laser, which contains the absorption information of the target gas, using an electrical signal Sda. Here, by repeatedly transmitting rectangular pulses of laser 1, multiple cumulative analyses are performed corresponding to multiple rectangular pulses, thereby improving the analytical accuracy by calculating their average value.

[0067] The analysis device 23 analyzes the concentration or temperature of the gas to be measured based on the signal waveform of the input electrical signal Sda. The analysis is performed, for example, by the following method: The analysis device 23 pre-includes information on the theoretical values ​​of the signal waveforms of the measured light intensity signals (electrical signals) for various concentrations or temperatures of the gas to be measured. The analysis device 23 compares the actual signal waveform obtained from the measurement with the theoretical values ​​of the signal waveforms, and determines the theoretical value of the signal waveform when their error is minimized. Then, by calculating the concentration and temperature associated with this determined theoretical value, the measured value of the concentration or temperature of the gas to be measured can be obtained.

[0068] It should be noted that the analysis of gas concentration and temperature is preferably synchronized based on the clock signal within the laser control device 14. Alternatively, instead of the clock signal within the laser control device 14, the clock signal can be regenerated from the received electrical signal Sda, and the analysis of gas concentration and temperature can be performed synchronously with the regenerated clock signal.

[0069] Figure 7 This is an absorption spectrum showing the wavelength characteristics of the absorbance when the target gas in the gas analyzer 10 is H2O. Additionally, Table 1 shows an example of the relationship between the target gas and the absorption wavelength λ. This is to make the corresponding... Figure 2 The wavelength λa of the falling portion Ld1 becomes within the wavelength scanning range Lw1. Figure 7 Alternatively, the amplitude E1 of the intensity of laser 1 can be set using the absorption wavelength method shown in Table 1.

[0070] [Table 1]

[0071] Determination object Absorption wavelength (nm) Water 1390 Carbon dioxide 1960 Carbon monoxide 1570 Carbon monoxide 2330 Nitric oxide 1800 Nitric oxide 2650 Dinitrogen dioxide 680 Dinitrogen monoxide 2260 Sulfur dioxide 240 Methane 1650 Acetylene 1520 Hydrogen fluoride 1310 Hydrogen chloride 1790 Hydrogen bromide 1960 Hydrogen iodide 1540 Hydrogen cyanide 1540 Hydrogen sulfide 1570 Ozone 280 Ammonia 1500 Formaldehyde 1930 Phosphine 2150 Oxygen 760

[0072] As described above, according to this embodiment, the laser control device 14 changes the excitation current value for the laser 11 synchronously with a clock signal of a predetermined frequency, such as... Figure 2As shown, the intensity of the laser light 1 is changed in a rectangular pulse shape, and at this time, the intensity of the laser light 1 is substantially constant as the maximum intensity El of the rectangular pulse for the time period Tl, with a flat portion Lfl. At this time, the wavelength of the laser light 1 is slightly delayed from the rise of the light intensity, and changes substantially in proportion to time within the wavelength scan range Lwl, from the wavelength λl to the wavelength λ2, with the rise of the temperature of the laser 11. That is, the laser control device 14 is able to control the laser 11 to output the laser light 1 while changing (scanning) the wavelength of the laser light 1 with time. Here, by setting the absorption wavelength λa of the measurement target gas between the wavelengths λl and λ2, a falling portion Ldl of the output voltage of the electric signal Sd from the photodetector 19 is generated in the prescribed absorption wavelength λa. By analyzing the electric signal Sda in the falling portion Ldl as described above, the concentration and the temperature of the measurement target gas can be measured.

[0073] That is, the laser control device 14 controls the laser 11 in such a manner that the intensity of the laser light 1 is changed in a rectangular shape having at least a substantially flat flat portion Lfl of the amplitude El for the prescribed time period Tl, and the wavelength of the laser light 1 is changed for the time period Tl. Thereby, the detection accuracy and the detection sensitivity of the gas analysis can be greatly improved compared to the prior art. In addition, Figure 1A The gas analysis device 10 of the embodiment 1 is configured using one laser, and can simplify the structure compared to the gas analysis device of the patent document 3 using two lasers.

[0074] (Modified example of the embodiment 1)

[0075] In the above embodiment 1, Tl = T2 is provided, but by providing Tl > T2, the wavelength scan range Lwl of the laser light 1 can be made larger than the case of Tl = T2. However, as shown in Figure 2 In the rise and the fall of the intensity of the laser light 1, the wavelength of the laser light 1 is slightly delayed and reaches the wavelength scan range Lwl, and then exceeds the range via the wavelength scan range Lwl, and thus it is desirable to set the duty ratio of the intensity of the laser light 1 to be, for example, 80% or less. However, when the duty ratio is excessively reduced, the wavelength scan range Lwl becomes narrow, and thus a trade-off is required for those cases, and for example, the duty ratio is preferably 30% or more.

[0076] In addition, by setting the absorption wavelength λa at a position of substantially half of the wavelength scan range Lwl, the falling portion Ldl of the output voltage can be set at a position of substantially half of the wavelength scan range Lwl. Thereby, the analysis of the measurement target gas can be performed with high accuracy without involving the portion where the wavelength is uncertain.

[0077] Embodiment

[0078] (Embodiment 1)

[0079] Figure 8 to Figure 10 are experimental results of the embodiment of the gas analysis device 10 of Embodiment 1, and are waveform charts of the output voltage of the photodetector 19 when the target gas is H2O and the chamber pressure is 100 Torr, 50 Torr, and 10 Torr. Here, the specification conditions in the applicable test of the embodiment are shown below.

[0080]

[0081] From Figure 8 to Figure 10 It is clear that the falling portion Ldl is generated within the wavelength scan range Lwl, showing that the analysis of the measurement target gas can be performed by the analyzing device 23.

[0082] In the gas analysis device 10 of the present embodiment, the following measures are taken in order to improve the sensitivity and the detection accuracy.

[0083] (1) The accumulation time is set to 1 second, which is about 10 times that of the related art. In addition, the number of accumulations is increased.

[0084] (2) A cooled photodetector is used as the photodetector 19, and a cooled photodetector having a detection sensitivity about 10 times that of the related art is used.

[0085] (3) The amplification degree of the AC amplifier 21 is made about 10 times that of the related art.

[0086] (4) The intensity of the laser light 1 from the laser 11 is made about 10 times that of the related art.

[0087] (5) The noise in other circuits is reduced compared to the related art.

[0088] <Embodiment 2>

[0089] Figure 3 is a block diagram showing a structure example of the gas analysis device 10A of Embodiment 2. In addition, Figure 4 is a graph showing the action of the gas analysis device 10A of Figure 3 is a graph showing the action of the gas analysis device 10A of Figure 1A The gas analysis device 10A of Embodiment 2 has the following points different from the gas analysis device 10 of Embodiment 1.

[0090] (1) The laser 12 that emits the laser light 2 is further included.

[0091] (2) Instead of the laser control device 14, a laser control device 14A that controls the two lasers 11, 12 is included. Here, the laser control device 14A is configured to include: Figure 1B a controller 60, two signal generators 61 Figure 1B , and two current power supplies 62 Figure 1B .

[0092] (3) A combiner 15 is provided between the lasers 11, 12 and the collimator 17.

[0093] (4) Instead of the analysis device 23, an analysis device 23A that analyzes each portion of the electrical signals corresponding to the two lasers 1, 2 in a time-division manner is included.

[0094] Hereinafter, the differences will be described.

[0095] The laser control device 14A changes the excitation current value to the laser 11 in synchronization with a clock signal of a prescribed frequency, as shown in FIG. 6, and changes the intensity of the laser 1 in a rectangular pulse shape with, for example, a duty ratio of 50% (time period T1=T2). By thus controlling the laser 11, the intensity of the laser 1 is substantially constant at the maximum intensity E1 of the rectangular pulse during the time period T1, and has a flat portion Lf1. Figure 4

[0096] In addition, the laser control device 14A changes the excitation current value to the laser 12 in synchronization with an inverted clock signal that is generated by inverting the clock signal, as shown in FIG. 7, and changes the intensity of the laser 2 in a rectangular pulse shape with, for example, a duty ratio of 50% (time period T1=T2). By thus controlling the laser 12, the intensity of the laser 2 is substantially constant at the maximum intensity E2 of the rectangular pulse during the time period T2, and has a flat portion Lf2. Figure 4

[0097] That is, as shown in FIG. 8, the laser control device 14A controls the lasers 11, 12 so that the laser 1 and the laser 2 are alternately repeated and changed in a rectangular pulse shape at substantially the same maximum intensities E1, E2 (E1«E2). Here, the intensities E1, E2 can be determined from the difference between the maximum intensities E1, E2, and controlled as follows. Figure 4

[0098] (1) For example, in order to increase the accuracy of moisture detection in a semiconductor processing device, as described later, it is preferable that the intensity of the flat portions Lf1, Lf2 each vary relative to the maximum intensities E1, E2, for example, be set to a threshold value of 10 -6 % or less of the maximum intensities E1, E2.

[0099] (2) It is preferable that the difference between E1, E2 relative to the maximum intensities E1, E2, for example, be set to a threshold value of 10​​​-6 The following.

[0100] At this time, as in Embodiment 1, the wavelength of the laser light 1 changes monotonously in proportion to time with the rise in the temperature of the laser 11, from the rise in the light intensity, within a wavelength scan range Lwl, for example, from the wavelength λl to the wavelength λ2. That is, the laser controller 14 is able to control the laser 11 to output the laser light 1 from the laser 11 while changing (scanning) the wavelength of the laser light 1 over time.

[0101] In addition, the wavelength of the laser light 2 changes monotonously in proportion to time with the rise in the temperature of the laser 12, from the rise in the light intensity, within a wavelength scan range Lw2 (Lwl « Lw2, but there are also cases where there is a slight difference), for example, from the wavelength λ3 to the wavelength λ4. That is, the laser controller 14A is able to control the laser 12 to output the laser light 2 from the laser 12 while changing (scanning) the wavelength of the laser light 2 over time.

[0102] Here, by setting the absorption wavelength of the first measurement target gas between the wavelengths λl to λ2 of the laser light 1, a falling portion Ldl of the output voltage of the electric signal Sd from the photodetector 19 is generated in a prescribed wavelength λal. In addition, by setting the absorption wavelength of the second measurement target gas between the wavelengths λ3 to λ4 of the laser light 2, a falling portion Ld2 of the output voltage of the electric signal Sd from the photodetector 19 is generated in a prescribed wavelength λa2 (λal « λa2, but there are also cases where there is a slight difference).

[0103] The two laser lights 1, 2 from the lasers 11, 12 are combined by the combiner 15, and the combined light 4 is input to the photodetector 19 after being irradiated to the measurement target gas via the collimator 17 that makes the combined light 4 parallel and focuses it. The photodetector 19 receives the laser light that has transmitted through the measurement target gas, and photoelectrically converts it into an analog electric signal Sd that includes an AC component according to the intensity of the received laser light. The AC amplifier 21 has an amplification band that is able to sufficiently amplify the AC component of the electric signal Sd (particularly, since the intensity of the laser light 1 sharply rises or falls, there are high harmonic components), amplifies the analog electric signal Sd from the photodetector 19, and outputs the amplified electric signal Sda to the analysis device 23. Then, the analysis device 23 inputs the analog electric signal Sda from the AC amplifier 21 and AD-converts it by the built-in AD converter, and as is well known, analyzes the waveform (absorption spectrum) of the electric signal Sda, and analyzes the concentration and temperature of the measurement target gas (for example, refer to Non-Patent Documents 1 and 2). The analysis device 23 is able to be realized by, for example, a computer (information processing device).

[0104] Here, the analysis device 23A of Embodiment 2 is synchronized based on a clock signal within the laser control device 14 or a clock signal reproduced by the analysis device 23A, and performs analysis processing of the gas concentration and the temperature by time-division processing of the electric signal Sda. That is, during the time period T1, analysis processing (including signal accumulation) of the measurement target gas having the absorption wavelength λal is performed, and during the time period T2, analysis processing (including signal accumulation) of the measurement target gas having the absorption wavelength λa2 is performed. Thus, analysis of the two measurement target gases can be performed substantially simultaneously.

[0105] In the gas analysis device 10A configured as above, for example, in a prescribed wavelength band of λ1 to λ2 including the estimated absorption wavelength λa, the laser 1 output from the laser 11 is scanned in wavelength while irradiating the measurement target gas with the laser 1, and, for example, in a prescribed wavelength band of λ3 to λ4 including the estimated absorption wavelength λa2, the laser 2 output from the laser 12 is scanned in wavelength while irradiating the measurement target gas with the laser 2. At this time, by analyzing the absorption spectrum of the laser of the electric signal Sda including the absorption information of the measurement target gas obtained, measurement of the concentration or the temperature of the measurement target gas is performed. Here, by repeating the rectangular pulse waves of the lasers 1, 2, analysis of each rectangular pulse wave of each laser 1, 2 is accumulated multiple times, and the analysis accuracy can be improved by calculating the average value thereof.

[0106] Further, as in Embodiment 2, by irradiating the target gas with the combined wave of the two lasers 1, 2 having mutually different maximum intensities El, E2 and obtaining the absorption spectrum, compared with the related art, the change in the absorption amount can be detected with high accuracy with a simple structure. Further, the number of accumulations per prescribed time can be doubled, and the analysis accuracy can be improved compared with the related art.

[0107] (Modified Example of Embodiment 2)

[0108] In the above embodiment 2, it is assumed that E1≈E2 and analysis is performed on the same measurement target gas in substantially the same absorption wavelength band, but the present application is not limited to this, and it is also possible to assume E1≠E2 and perform analysis on different measurement target gases in mutually different absorption wavelength bands. In this case, in addition to laser light including a wavelength band in which a wavelength is absorbed by a measurement target gas component, laser light including a wavelength band in which a wavelength is absorbed by a gas component different from the measurement target gas component is used, whereby simultaneous measurement of a plurality of gas components can be performed. Here, it is preferable that the wavelength scanning ranges Lw1, Lw2 be set in such a manner that, in the analysis of different measurement target gases in the time periods T1, T2, there is one measurement target gas absorption wavelength λa1 in the wavelength scanning range Lw1, and there is a measurement target gas absorption wavelength λa2 in the wavelength scanning range Lw2.

[0109] In the above embodiment 2, it is assumed that T1=T2, but it is also possible to assume T1≠T2. Thereby, it is also possible to make the wavelength scanning range Lw1 of the laser light 1 and the wavelength scanning range Lw2 of the laser light 2 mutually different. However, as explained in the modified example of embodiment 1, it is preferable that the setting of the wavelength scanning ranges Lw1, Lw2 be performed taking into account the duty ratio of the rectangular pulse wave.

[0110] In addition, by setting the absorption wavelength λa1 at a position of substantially half of the wavelength scanning range Lw1, it is possible to set the drop portion Ld1 of the output voltage at a position of substantially half of the wavelength scanning range Lw1. By setting the absorption wavelength λa2 at a position of substantially half of the wavelength scanning range Lw2, it is possible to set the drop portion Ld2 of the output voltage at a position of substantially half of the wavelength scanning range Lw2. Thereby, it is possible to perform analysis of the measurement target gas with high accuracy without involving a portion in which the wavelength is indefinite.

[0111] <Embodiment 3>

[0112] Figure 5 is a block diagram showing a configuration example of the gas analysis device 10B of embodiment 3. The gas analysis device 10B of embodiment 3 differs from the gas analysis device 10A of embodiment 2 of Figure 3 in the following points.

[0113] (1) A laser 13 that emits laser light 3 is further included.

[0114] (2) Instead of the laser controller 14A, a laser controller 14B that controls the three lasers 11, 12, 13 is included.

[0115] (3) The substitution analysis device 23A includes an analysis device 23B that analyzes each portion of the electric signal corresponding to the three lasers 1, 2, 3 in a time-division manner.

[0116] By the above configuration, by repeatedly sequentially emitting the rectangular pulse waves of the lasers 1, 2, 3 without overlapping, performing analysis of the multiple accumulations corresponding to each of the multiple rectangular pulse waves of each of the lasers 1, 2, 3, and calculating the average value, the analysis accuracy can be improved.

[0117] Here, the maximum intensities E1, E2, E3 of the lasers 1, 2, 3 can be set to be the same as each other, or can be set to be different from each other or at least two of them are the same. Thereby, the wavelength range corresponding to the wavelength setting range and containing the absorption wavelength can be set to be the same as each other or different from each other, or at least two of them are the same.

[0118] In addition, the time-in-period E1, E2, E3 of each of the lasers 1, 2, 3 can be set to be the same as each other, or can be set to be different from each other or at least two of them are the same. However, the length of the time-in-period E1, E2, E3, the wavelength scanning range varies as in Embodiment 2, and the matters to be noted in the setting in Embodiment 2 are the same.

[0119] Note that, in Embodiment 3, three lasers 11, 12, 13 are used and the three lasers 1, 2, 3 are combined, but the present application is not limited to this, and four or more lasers can be used and four lasers can be combined, for example, to analyze four or more different measurement target gases.

[0120] <Embodiment 4>

[0121] Figure 6 is a waveform chart showing the intensity of the laser 1 of the modification example of Embodiments 1 to 3. As shown in Figure 6 , the laser 11 can be controlled so that the shape of the intensity of the laser 1 and the like is a trapezoidal shape, not a rectangular shape. This can be widely applied to Embodiments 1 to 3 and the modification examples thereof.

[0122] However, in order to make the wavelength scanning range Lw1 as long as possible, the rising portion Lfa and the falling portion Lfb of the trapezoid are preferably increased in inclination so as to be sharply raised or sharply lowered. In addition, one of the rising portion Lfa and the falling portion Lfb of the trapezoid can be configured to be an angle of substantially 90° or -90°.

[0123] <Embodiment 4>

[0124] Figure 11is a block diagram showing a configuration example of the two-dimensional gas analysis device 10C of Embodiment 4. In Embodiments 1 to 3, the structure of the gas analysis device 10, 10A, 10B having one path (optical path) to one-dimensionally measure the state of the measurement target gas was described. In Embodiment 4, in order to be able to two-dimensionally measure the concentration or temperature of the measurement target gas, the structure of a two-dimensional gas analysis device capable of measurement by a plurality of paths will be described.

[0125] Generally known X-ray computed tomography (CT: Computed Tomography) is a technique of scanning an object with X-rays and subdividing the cross section thereof, measuring the X-ray absorption amount of each of the divided elements, and constructing the cross section of the object by collecting information of the same amount of X-ray absorption as the unknown. When a measurement target gas contains a large amount of water vapor, carbon dioxide, or the like, the irradiated light is partially absorbed and attenuated at a certain wavelength when passing through those chemical species having an inherent absorption spectrum. In the absorption method, the integral value of the light transmitted through the light path of the measurement field is measured as the absorption amount. By irradiating a plurality of lasers to the measurement field and reconstructing a two-dimensional image by using the CT technique, it is possible to measure a two-dimensional temperature distribution.

[0126] (Structure of Two-Dimensional Gas Analysis Device)

[0127] Figure 11 The two-dimensional gas analysis device 10C is a two-dimensional gas analysis device capable of two-dimensionally measuring the concentration or temperature of a measurement target gas, and is configured to include two lasers 11, 12, a laser control device 14A, a beam combiner 15, an optical fiber splitter 31, a measurement unit 30, and an analysis device 23C. Here, the AC amplifier 21 is built into the analysis device 23C.

[0128] The measurement unit 30 has a frame 33 having an opening and a substantially circular shape. For the frame 33, in order to measure the transmitted light intensity of 16 light paths (paths), 16 collimators 17 and 16 light detectors 19 disposed opposite to each collimator 17 are installed. Therefore, at the opening of the measurement unit 30, a pair of collimator 17 and light detector 19 forms a path (light path). That is, the measurement unit 30 has 16 paths (light paths). Each path (light path) is configured to be included in the same plane in which two-dimensional measurement is possible. Note that hereinafter, the normal direction of the plane including each path (light path) will be referred to as the "normal direction of the measurement unit 30".

[0129] The measurement unit 30 having such a structure is disposed in a measurement field including a measurement target gas, and the two-dimensional gas analysis device 10C performs measurement of the gas components in the opening region of the measurement unit 30.

[0130] The laser 11 outputs laser light 1 including a wavelength band of an absorption wavelength λal absorbed by a component of a first measurement target gas, and the laser 12 outputs laser light 2 including a specific wavelength λa2 not absorbed by the component of the first measurement target gas or a component of a second measurement target gas different from the component of the first measurement target gas. In addition, the laser 11 and the laser 12 output laser lights 1 and 2 having different directions of intensity variation or different maximum intensities El and E2.

[0131] The laser lights 1 and 2 emitted from the laser 11 and the laser 12, respectively, are input to the combiner 15, and the combined light after combination is input to the fiber splitter 31. The fiber splitter 31 branches the combined light into 16 branched lights and inputs the branched lights to the 16 collimators 17, respectively. Each branched light is irradiated to the measurement field via the collimator 17. The laser light transmitted through the measurement field is received by each light detector 19, photoelectrically converted into an electric signal, and input to the analysis device 23.

[0132] The analysis device 23 analyzes the signal waveform of the electric signal from each light detector 19 and reconstructs a two-dimensional image showing the concentration and / or temperature distribution of the gas component. The reconstruction of the two-dimensional image can be performed using the existing CT technology.

[0133] In the above embodiment 4, an example in which the number of paths (optical paths) is 16 is described, but the number of paths (optical paths) is not limited to 16, and can be 8, 12, or the like.

[0134] According to the two-dimensional gas analysis device 10C of the above embodiment 4, it is possible to two-dimensionally measure the distribution of the temperature or the concentration of the measurement target gas. In particular, by making the amplitudes of the two laser lights different, it is possible to eliminate the effect of the attenuation of the laser intensity due to the effect other than the original absorption of the gas component as the object of the contamination of the window, and thus it is possible to prevent the reduction in the analysis accuracy of the gas.

[0135] <APPLICATION EXAMPLE>

[0136] Hereinafter, an application example of the two-dimensional gas analysis device 10C of the embodiment 4 will be described. Note that in the following application example, the gas analysis devices 10 to 10B of the embodiments 1 to 4 can also be used.

[0137] (Application Example 1)

[0138] Figure 12 is a schematic view of an application example 1 of the two-dimensional gas analysis device 10C of Figure 11 in the combustor 100.

[0139] As described above, in the two-dimensional gas analysis device 10C of the embodiment 4, the laser 11 and the laser 12 output laser lights 1 and 2 having different directions of intensity variation or different maximum intensities El and E2. Therefore, it is possible to prevent the reduction in the analysis accuracy of the gas. Figure 12As shown, the two-dimensional gas analysis device 10C can be applied to detection of the combustion state (temperature and concentration of the target gas) in the combustion chamber of the burner 100 used in a thermal power plant or the like. For example, by arranging the measurement unit 30 of the two-dimensional gas analysis device 10C in the combustion chamber 110 of the boiler, the combustion state in the combustion chamber 110 of the burner 100 can be grasped two-dimensionally. Further, for the combustion chamber 110, by arranging a plurality of measurement units 30 in the normal direction thereof, the combustion state can also be measured three-dimensionally. Figure 11

[0140] (Application Example 2)

[0141] Figure 13 is a schematic view showing an application example 2 of the two-dimensional gas analysis device 10C in an engine 200. Figure 11 As shown, the two-dimensional gas analysis device 10C can be applied to detection of the combustion state (temperature and concentration of the target gas) in the combustion chamber of the burner 100 used in a thermal power plant or the like. For example, by arranging the measurement unit 30 of the two-dimensional gas analysis device 10C in the combustion chamber 110 of the boiler, the combustion state in the combustion chamber 110 of the burner 100 can be grasped two-dimensionally. Further, for the combustion chamber 110, by arranging a plurality of measurement units 30 in the normal direction thereof, the combustion state can also be measured three-dimensionally.

[0142] Figure 13 As shown, the two-dimensional gas analysis device 10C can be applied to detection of the combustion state (temperature and concentration of the target gas) in the combustion chamber of the burner 100 used in a thermal power plant or the like. For example, by arranging the measurement unit 30 of the two-dimensional gas analysis device 10C in the combustion chamber 110 of the boiler, the combustion state in the combustion chamber 110 of the burner 100 can be grasped two-dimensionally. Further, for the combustion chamber 110, by arranging a plurality of measurement units 30 in the normal direction thereof, the combustion state can also be measured three-dimensionally. Figure 13 Figure 11 As shown, the two-dimensional gas analysis device 10C can be applied to detection of the combustion state (temperature and concentration of the target gas) in the combustion chamber of the burner 100 used in a thermal power plant or the like. For example, by arranging the measurement unit 30 of the two-dimensional gas analysis device 10C in the combustion chamber 110 of the boiler, the combustion state in the combustion chamber 110 of the burner 100 can be grasped two-dimensionally. Further, for the combustion chamber 110, by arranging a plurality of measurement units 30 in the normal direction thereof, the combustion state can also be measured three-dimensionally. Figure 11 Figure 11 As shown, the two-dimensional gas analysis device 10C can be applied to detection of the combustion state (temperature and concentration of the target gas) in the combustion chamber of the burner 100 used in a thermal power plant or the like. For example, by arranging the measurement unit 30 of the two-dimensional gas analysis device 10C in the combustion chamber 110 of the boiler, the combustion state in the combustion chamber 110 of the burner 100 can be grasped two-dimensionally. Further, for the combustion chamber 110, by arranging a plurality of measurement units 30 in the normal direction thereof, the combustion state can also be measured three-dimensionally.

[0143] According to the application example 2 configured as above, detection of the temperature and concentration of various gases in the working cylinder 210 of the engine 200 or in the exhaust system can be performed, which is useful for elucidating the transient state of combustion or the behavior of unburned fuel discharge.

[0144] (Application Example 3)

[0145] Figure 14 is a schematic view showing an application example 3 of the two-dimensional gas analysis device 10C in a jet engine 300. Figure 11 As shown, the two-dimensional gas analysis device 10C can be applied to detection of the combustion state (temperature and concentration of the target gas) in the combustion chamber of the burner 100 used in a thermal power plant or the like. For example, by arranging the measurement unit 30 of the two-dimensional gas analysis device 10C in the combustion chamber 110 of the boiler, the combustion state in the combustion chamber 110 of the burner 100 can be grasped two-dimensionally. Further, for the combustion chamber 110, by arranging a plurality of measurement units 30 in the normal direction thereof, the combustion state can also be measured three-dimensionally.

[0146] Figure 14 ​​​​​As shown, the two-dimensional gas analysis device 10C can be applied to detection of the combustion state (temperature and concentration of the object gas) of a jet engine or an industrial gas turbine. In the jet engine 300 (or gas turbine), the intake air is compressed by a compressor driven by the rotational force of a turbine 303, mixed with fuel in a combustor 301, and combusted. The combustion gas generated by the combustion rotates the turbine 303, and is discharged to the outside from a jet port. For example, as shown, the measurement unit 30 can be disposed near the jet port 305 of the jet engine 300. Thereby, the combustion state inside the combustor 301 of the jet engine 300 can be detected. Such a technique is useful for investigating vibration phenomena due to flow field and fuel non-uniformity. In addition, a plurality of measurement units 30 can be arranged in the direction of discharge of the combustion gas near the jet port 305. Thereby, the combustion state can be detected three-dimensionally. Figure 13 Figure 11

[0147] According to Application Example 3 configured as above, by applying the structure of the gas analysis device combining the CT technique and the laser to a method of measuring the temperature distribution and the concentration distribution two-dimensionally or three-dimensionally, it is possible to expand application to combustion equipment such as a boiler, an engine, and a gas turbine, while achieving simplification and quantification of the device, and high sensitivity.

[0148] (Application Example 4)

[0149] Figure 15 is a schematic view of Application Example 4 of the two-dimensional gas analysis device 10C shown in Figure 11 in a semiconductor process, Figure 16 is a flowchart showing this Application Example 4.

[0150] In Figure 15 and Figure 16 , the semiconductor process includes, for example, a wafer manufacturing step (S1), a pre-step (S2), and a post-step (S3). In the wafer manufacturing step (S1), a semiconductor wafer is manufactured, in the pre-step (S2), in a chamber, a wafer is placed on a placement table, and a prescribed semiconductor film is formed on the wafer using a film formation device. Also, in the post-step (S3), the wafer is cut and each semiconductor chip is assembled.

[0151] In the above semiconductor process, particularly in the pre-step (S2), a semiconductor with high purity cannot be formed when there is moisture in the chamber, and thus in order to ensure this, moisture detection measurement is required. By removing moisture while measuring the moisture using the gas analysis devices 10 to 10C of Embodiments 1 to 4, it is possible to achieve a chamber internal environment that is substantially moisture-free.

[0152] (Application Example 5)

[0153] ​​Figure 17 is a schematic view showing application example 5 of the two-dimensional gas analyzer 10C of Figure 11

[0154] In Figure 17 , the denitration device 400 is a device that performs denitration of, for example, NO x gas, and is configured to have the gas analyzer 10 provided in an exhaust pipe 410, and to control the amount of injection of NH3 in the injection valve 430 in the NH3 injection pipe 420 based on the measured value of NH3.

[0155] In the NH3 measuring meter of the indirect NO x x method represented by the chemiluminescence method or the two-ion electrode method in the related art, there is a problem that the maintenance burden is large due to the use of a sample line provided with a heating conduit, a complex measurement system, and slow responsiveness in order to prevent adsorption of NH3.

[0156] In this regard, in the NH3 measurement in Figure 17 , since the measurement is performed directly on the exhaust pipe 410 as a production line, the responsiveness and the maintenance can be greatly improved compared to the related art. Furthermore, the measurement signal of the NH3 concentration with good responsiveness is actively used for the control of the amount of injection of NH3, and optimization of the injection of NH3 can also be achieved.

[0157] (Application Example 6)

[0158] Figure 18 is a flowchart showing application example 6 of the two-dimensional gas analyzer 10C of Figure 11 in the waste gas denitration system 500.

[0159] In Figure 18 , the waste gas denitration system 500 includes a boiler 501, an economizer 502, a denitration device 503, an air heater 504, a dust collecting device 505, and an exhaust stack 506. The denitration device 503 is provided for the purpose of improving the dust collection rate of the dust collecting device and preventing corrosion. In Figure 17 , the injection point of NH3 is basically the denitration device 503, but when the denitration device 503 is not present, it is provided between the air heater 504 and the dust collecting device 505 as shown in Figure 18 . Here, the two-dimensional gas analyzer 10C is provided, for example, at 511, 512, and 513.

[0160] In application example 6 configured as above, it is possible to measure NH3 with high accuracy and perform waste gas denitration. In particular, by using the two-dimensional gas analyzer 10C, it is possible to obtain improvements in high component selectivity, high-speed responsiveness, and maintenance compared to the related art.

[0161] (Application Example 7) ​

[0162] For example, in thermal power plants, the gas analysis apparatus 10 to 10C of the embodiments can be configured as follows.

[0163] (1) In a boiler, by using the gas analysis apparatus 10 to 10C to perform analysis control of the gas, the amount of No x , CO, and excess O2 can be reduced, and thus the combustion efficiency can be greatly improved compared to the related art.

[0164] (2) In a gas treatment apparatus that discharges from a boiler, the denitration efficiency can be improved, the ammonia leakage can be reduced, and the life of the denitration catalyst can be extended compared to the related art.

[0165] (Summary of application examples)

[0166] As described above, according to the application examples of the gas analysis apparatus 10 to 10C of the embodiments, improvements in high component selectivity, high-speed responsiveness, and maintenance can be obtained compared to the related art. Here, not only NH3 measurement, but also CO, O2 measurement under optimal combustion control, measurement of trace amounts of moisture in electrolytic equipment or semiconductor processes, and the like are widespread in various industrial process applications, and not only simple monitoring, but also process control can be combined, and thus great contributions to environmental protection and reduction of operating costs can be made.

[0167] (Additional embodiments)

[0168] Embodiment 1

[0169] Figure 19 is a waveform chart of the output voltage of the photodetector 19 when the object gas is H2O and the chamber pressure is 10 Torr (1.3 kPa) in Embodiment 1 of the gas analysis apparatus 10 in Embodiment 1. Here, the specification conditions in the applicability test of Embodiment 1 are shown below.

[0170]

[0171]

[0172] According to the test results of Embodiment 1 of Figure 19 , the signal-to-noise ratio (S / N) is 129 dB, and the atmospheric pressure conversion concentration can be 1 ppb. From Figure 19 , it can be confirmed that the laser light can be generated in a manner in which each flat portion has a falling portion Ldl.

[0173] Embodiment 2

[0174] Figure 20is an experimental result of Embodiment 2 of the gas analysis device 10A in Embodiment 2, and is a waveform chart of the output voltage of the photodetector 19 when the target gas is H2O and the chamber pressure is 10 Torr (1.3 kPa). Here, the specification conditions in the application test of Embodiment 2 are as shown below.

[0175]

[0176] According to Figure 20 the experimental result of Embodiment 2, it is clear from Figure 20 that the laser light can be generated in a manner that each of the flat portions has a drop portion Ldl, Ld2.

[0177] Embodiment 3

[0178] Figure 21 is an experimental result of Embodiment 2 of the gas analysis device 10A in Embodiment 2, and is a waveform chart of the output voltage of the photodetector 19 showing that the amplification as an AC signal can be improved.

[0179] In the prior art example, when measurement is performed using laser light having a sawtooth wave of laser light intensity, when the amplification as an AC signal is increased, a saturated state is generated in the upper and lower portions of the AC signal and the generation of the laser light becomes unstable, and there is a problem that there is an upper limit to the amplification in order to stabilize the operation. In this regard, in the experimental result of Embodiment 2, by generating laser light in a manner that each flat portion has a drop portion, the amplification as an AC signal can be greatly improved, and in particular, the amplification degree of the voltage signal can be greatly improved in the flat portion. Thereby, as a gas analysis capability, a high sensitivity of about 100 times can be achieved.

[0180] Industrial applicability

[0181] As described in detail above, according to the present application, the laser light control means controls the laser light source so that the intensity of the laser light varies in a rectangular shape or a trapezoidal shape having at least a substantially flat amplitude in a prescribed time period, and the wavelength of the laser light varies in the time period. Thereby, the detection precision of gas analysis can be improved compared to the prior art.

[0182] In addition, according to the application example of the gas analysis device using the present application, high component selectivity, high speed responsiveness, and maintenance can be improved compared to the prior art. In particular, in semiconductor processes, by using the gas analysis device of the present application, moisture in a chamber in which a prescribed film is formed on a semiconductor wafer can be detected with high precision compared to the prior art, and the moisture can be removed, which is extremely effective in industry.

[0183] Furthermore, the gas analysis device using the present application is considered to be used in the following industries.

[0184] (1) In the automobile industry, exhaust gas management and combustion control can be performed. In particular, as an exhaust gas measuring device, it can be used in a new engine development tool for automobile manufacturers.

[0185] (2) In various industrial equipment, engineering process management and control can be performed.

[0186] (3) Process monitoring and control in various equipment can be performed. For example, it can be used for quality management or control in production processes such as synthetic chemical equipment, steel equipment, etc., and can monitor specific components contained in raw materials or products, etc.

[0187] Explanation of Reference Numerals

[0188] 1, 2, 3 Laser light

[0189] 4 Combined light

[0190] 10, 10C, 10B Gas analysis device

[0191] 10C Two-dimensional gas analysis device

[0192] 11, 12, 13 Laser

[0193] 14, 14A, 14B Laser control device

[0194] 14b Measurement control device

[0195] 15 Combiner

[0196] 17 Collimator

[0197] 19 Light detector

[0198] 21 AC amplifier

[0199] 23, 35 Analysis device

[0200] 30 Measurement unit of two-dimensional gas analysis device

[0201] 31 Fiber splitter

[0202] 33 Frame

[0203] 41, 42 Electrode

[0204] 43 p-cladding

[0205] 44 Active layer

[0206] 45 n-cladding

[0207] 46 n-substrate

[0208] 51 reflecting surface

[0209] 60 controller

[0210] 61 waveform generator

[0211] 62 current power supply

[0212] 100 combustor

[0213] 110 combustion chamber

[0214] 200 vehicle engine

[0215] 210 working cylinder

[0216] 220 exhaust pipe

[0217] 300 jet engine

[0218] 301 combustor

[0219] 303 turbine

[0220] 305 injection port

[0221] 400 denitration device

[0222] 410 exhaust pipe

[0223] 420 injection pipe

[0224] 430 injection valve

[0225] 500 exhaust gas denitration system

[0226] 501 boiler

[0227] 502 economizer

[0228] 503 denitration device

[0229] 504 air heater

[0230] 505 dust collecting device

[0231] 506 exhaust stack

[0232] 511 gas analyzing device

[0233] 512 gas analyzing device

[0234] 513 gas analyzing device

Claims

1. A gas analyzing apparatus comprising: a laser light source irradiating laser light to a measurement target gas; a laser controller controlling the laser light source in such a manner that the wavelengths of the laser light each vary within a prescribed wavelength band; a light detecting section photoelectrically converting the laser light transmitted through the measurement target gas and outputting an electric signal; and a resolution section analyzing an absorption wavelength of the measurement target gas based on the electric signal, wherein the laser controller includes: a signal generator generating a voltage signal of a rectangular wave or a trapezoidal wave; and a current power source converting the voltage signal into a driving current of a rectangular wave or a trapezoidal wave and flowing the driving current into the laser light source, the laser controller controls the laser light source only with current control using the signal generator and the current power source so that the intensity of the laser light varies within a prescribed time period in a shape having at least a substantially constant flat portion, whereby the output of the laser light, the temperature of the laser light source, the diffraction grating interval of the laser light source, the wavelength of the laser light vary in the time period in proportion to time as the intensity of the laser light rises, the wavelength of the laser light lags behind the rise in the intensity of the laser light, and the wavelength of the laser light varies in the time period in proportion to time as the temperature of the laser light source rises.

2. The gas analyzing apparatus according to claim 1, wherein the shape is a rectangular shape or a trapezoidal shape.

3. A gas analyzing apparatus comprising: a plurality of laser light sources each outputting a laser light; a laser controller controlling the plurality of laser light sources each in such a manner that the wavelength of the laser light varies within a prescribed wavelength band; a combining section combining the plurality of laser lights and irradiating a measurement target gas with the combined light; a light detecting section photoelectrically converting the laser light transmitted through the measurement target gas and outputting an electric signal; and a resolution section analyzing an absorption wavelength of the measurement target gas based on the electric signal, wherein the laser controller includes: a signal generator generating a voltage signal of a rectangular wave or a trapezoidal wave; and a current power source converting the voltage signal into a driving current of a rectangular wave or a trapezoidal wave and flowing the driving current into the plurality of laser light sources, the laser controller controls the plurality of laser light sources only with current control using the signal generator and the current power source so that the plurality of laser lights are outputted in turn repeatedly without overlapping each other, the intensity of each of the laser lights varies within a prescribed time period in a shape having at least a substantially constant flat portion, whereby the output of each of the laser lights, the temperature of each of the laser light sources, the diffraction grating interval of each of the laser light sources, the wavelength of each of the laser lights vary in the time period in proportion to time as the intensity of each of the laser lights rises, the wavelength of each of the laser lights lags behind the rise in the intensity of each of the laser lights, and the wavelength of each of the laser lights varies in the time period in proportion to time as the temperature of each of the laser light sources rises.

4. The gas analyzing apparatus according to claim 3, wherein ​ ​ The shape is a rectangular shape or a trapezoidal shape.

5. The gas analysis device according to claim 3 or 4, wherein Each of the plurality of laser lights is substantially the same in intensity, and has a difference below a prescribed threshold value.

6. The gas analysis device according to claim 3 or 4, wherein The plurality of laser light sources include a first laser light source and a second laser light source, The first laser light source outputs a first laser light, The second laser light source outputs a second laser light, The laser light controller controls the first laser light source and the second laser light source so as to output the first laser light and the second laser light alternately and repeatedly.

7. The gas analysis device according to claim 6, wherein The gas analysis device further includes a branching member that branches the combined light into a plurality of light paths and irradiates the measurement target gas, The light detection member includes a plurality of light detectors that are provided corresponding to each of the plurality of light paths and output an electric signal by photoelectric conversion of the laser light transmitted through the measurement target gas, The analysis member analyzes the measurement target gas based on the plurality of electric signals output from each of the light detectors, The laser light controller controls the first laser light source and the second laser light source so that the amplitude of the first laser light and the amplitude of the second laser light are different from each other, The analysis member eliminates the influence of a variation in each electric signal from each of the light detectors due to factors other than absorption based on the difference between the amplitude of the first laser light and the amplitude of the second laser light.

8. The gas analysis device according to any one of claims 1 to 4, wherein The laser light controller controls each of the laser light sources so that the variation of the flat portion is below a prescribed threshold value.

9. The gas analysis device according to any one of claims 1 to 4, wherein The gas analysis device further includes an amplification member that is provided between the light detection member and the analysis member and amplifies the electric signal.

10. The gas analysis device according to claim 3 or 4, wherein The laser light controller controls the plurality of laser lights so that the amplitudes of the plurality of laser lights are substantially the same as each other during the time period and the plurality of laser lights vary in a wavelength band in which they are substantially the same as each other during the time period.

11. The gas analysis device according to claim 3 or 4, wherein The laser light controller controls the plurality of laser lights so that the amplitudes of the plurality of laser lights are different from each other during the time period and the plurality of laser lights vary in a wavelength band in which they are substantially different from each other during the time period.

12. A gas analysis method including the steps of: A laser light source irradiates a measurement target gas with laser light; The laser light source is controlled so that the wavelengths of the laser light each vary within a prescribed wavelength band; The laser light transmitted through the measurement target gas is photoelectrically converted and an electric signal is output; and An absorption wavelength of the measurement target gas is analyzed based on the electric signal, wherein The gas analysis method further includes the steps of: A signal generator generates a voltage signal of a rectangular wave or a trapezoidal wave; and A laser light source irradiates a measurement target gas with laser light; a current source converts the voltage signal into a driving current of a rectangular wave or a trapezoidal wave and causes the driving current to flow into the laser light source, the step of controlling the laser light source includes: controlling the laser light source only with current control using the signal generator and the current source, so that the intensity of the laser light changes in a shape having at least a substantially constant flat portion during a prescribed time period, whereby the output of the laser light, the temperature of the laser light source, the diffraction grating interval of the laser light source, the wavelength of the laser light change, the wavelength of the laser light lags behind the rise in the intensity of the laser light, and the wavelength of the laser light changes in proportion to the rise in the temperature of the laser light source substantially in proportion to time during the time period.

13. The gas analysis method according to claim 12, wherein the shape is a rectangular shape or a trapezoidal shape.

14. A gas analysis method, comprising the steps of: a plurality of laser light sources respectively outputting a plurality of laser lights; controlling the plurality of laser light sources respectively in such a manner that the wavelengths of the plurality of laser lights each change within a prescribed wavelength band; combining the plurality of laser lights and irradiating a measurement target gas with the combined light; photoelectrically converting laser light transmitted through the measurement target gas and outputting an electric signal; and analyzing an absorption wavelength of the measurement target gas on the basis of the electric signal, wherein the gas analysis method further comprises the steps of: a signal generator generating a voltage signal of a rectangular wave or a trapezoidal wave; and a current source converting the voltage signal into a driving current of a rectangular wave or a trapezoidal wave and causing the driving current to flow into the plurality of laser light sources, the step of controlling the plurality of laser light sources includes: controlling the plurality of laser light sources only with current control using the signal generator and the current source, so that the plurality of laser lights are output repeatedly in turn without overlapping each other, the intensity of each of the laser lights changes in a shape having at least a substantially constant flat portion during a prescribed time period, whereby the output of each of the laser lights, the temperature of each of the laser light sources, the diffraction grating interval of each of the laser light sources, the wavelength of each of the laser lights change, the wavelength of each of the laser lights lags behind the rise in the intensity of each of the laser lights, and the wavelength of each of the laser lights changes in proportion to the rise in the temperature of each of the laser light sources substantially in proportion to time during the time period.

15. The gas analysis method according to claim 14, wherein the shape is a rectangular shape or a trapezoidal shape.

16. The gas analysis method according to claim 14 or 15, wherein the intensity of each of the plurality of laser lights is substantially the same, and has a difference below a prescribed threshold value.

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