WO2017164033A1 - Gas measuring device - Google Patents

Gas measuring device Download PDF

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Publication number
WO2017164033A1
WO2017164033A1 PCT/JP2017/010390 JP2017010390W WO2017164033A1 WO 2017164033 A1 WO2017164033 A1 WO 2017164033A1 JP 2017010390 W JP2017010390 W JP 2017010390W WO 2017164033 A1 WO2017164033 A1 WO 2017164033A1
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Prior art keywords
light
absorption wavelength
gas
unit
measuring device
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PCT/JP2017/010390
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French (fr)
Japanese (ja)
Inventor
久一郎 今出
亮太 石川
義憲 井手
久典 川島
達雄 椎名
Original Assignee
コニカミノルタ株式会社
国立大学法人 千葉大学
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Application filed by コニカミノルタ株式会社, 国立大学法人 千葉大学 filed Critical コニカミノルタ株式会社
Priority to JP2018507260A priority Critical patent/JP6756999B2/en
Publication of WO2017164033A1 publication Critical patent/WO2017164033A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
    • G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
    • G01N21/39—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry using tunable lasers

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  • the present invention relates to a gas measuring device.
  • the conventional gas thickness measurement device for calculating the concentration / thickness product is based on the difference absorption method (DIAL, DOAS) for calculating the concentration / thickness product by taking the difference between the two received light signal intensity of absorption wavelength and non-absorption wavelength. It is possible to use a 2f detection method that modulates with a fundamental wave f centering on a line and obtains a concentration thickness product based on a received light signal ratio with the second harmonic wave 2f. The former is a calculation based on direct difference, and the calculation process itself for calculating the concentration-thickness product is simple and the distance can be measured. However, in order to emit two wavelengths, two laser diodes are used that slow the light emission period. Such complicated processing and device configuration are required.
  • the latter is a technique that can measure a very small signal change by taking out an output of a specific frequency and calculating it with high sensitivity and enabling a very compact design.
  • the calculation for calculating the concentration-thickness product is complicated, distance measurement is difficult, and it is difficult to speed up the light emission cycle.
  • Patent Document 1 irradiates laser light of two wavelengths, gas absorption wavelength and non-absorption wavelength, using a single laser light source, OPO (Optical Parametric Oscillation), and etalon plate, and the reflected light is dichroic.
  • OPO Optical Parametric Oscillation
  • etalon plate etalon plate
  • the present invention has been made in view of the above-described problems in the prior art, and is capable of detecting light emission and light reception and calculating the concentration-thickness product with a relatively simple configuration, while keeping the light emission output constant. It is an object of the present invention to provide a gas measuring device that can output by changing the wavelength over an absorption wavelength and a non-absorption wavelength.
  • the invention according to claim 1 for solving the above-described problems includes a light emitting unit that emits light for detecting a measurement target gas; A control unit for controlling light emission of the light emitting unit; A light receiving portion for receiving light emitted from the light emitting portion and passing through the space; A gas measurement device that calculates a concentration / thickness product of a measurement target gas in the space, and a calculation unit that processes a signal received by the light receiving unit,
  • the control unit gives a change over the absorption wavelength and non-absorption wavelength of the measurement target gas to the wavelength of light emitted by the light emitting unit by inputting a current that changes sharply to the light emitting unit
  • the calculation unit is a gas measurement device that calculates a concentration thickness product of the measurement target gas based on a light reception signal of the light having the absorption wavelength and a light reception signal of the light having the non-absorption wavelength received by the light reception unit.
  • the calculation unit is configured to calculate a concentration thickness product of a measurement target gas based on a difference between a light reception signal of the absorption wavelength light received by the light reception unit and a light reception signal of the non-absorption wavelength light. It is a gas measuring device of Claim 1 which computes.
  • the calculation unit obtains light reception signal time series data over the absorption wavelength and the non-absorption wavelength received by the light reception unit, and based on the light reception signal time series data, the measurement target The gas measuring device according to claim 1, wherein a gas concentration / thickness product is calculated.
  • the calculation unit integrates the light reception signal time-series data in an absorption line light reception period for receiving light of the absorption wavelength, and calculates the concentration thickness product of the measurement target gas based on the integration value.
  • the gas measuring device according to claim 3 to be calculated.
  • the calculation unit integrates in a non-absorption line light receiving period for receiving the light of the non-absorption wavelength, and based on the integration value and the integration value of the absorption line light reception period, the measurement object It is a gas measuring device of Claim 4 which calculates the concentration thickness product of gas.
  • a sixth aspect of the present invention is the gas measuring device according to any one of the first to fourth aspects, wherein the calculation unit determines a measurement error based on a light reception signal of the light having the non-absorbing wavelength. .
  • the invention according to claim 7 includes a reference indicating a light absorption wavelength of the measurement target gas, and a reference light receiving unit that receives the light emitted from the light emitting unit and passed through the reference,
  • the control unit obtains feedback of the light receiving signal of the reference light receiving unit and inputs a rectangular wave current to the light emitting unit, so that the absorption wavelength of the measurement target gas and the non-wavelength of light emitted from the light emitting unit are increased.
  • the calculation unit is configured to measure a measurement target gas based on a light reception signal of the light having the absorption wavelength received by the light reception unit and a light reception signal of the light having the absorption wavelength received by the reference light reception unit.
  • the gas measuring device according to claim 7, wherein the concentration-thickness product is calculated.
  • the calculation unit includes: the absorption wavelength received by the light receiving unit and the light reception signal time-series data over the non-absorption wavelength; and the absorption wavelength and the non-absorption received by the reference light receiving unit.
  • the invention according to claim 10 is the gas measuring device according to any one of claims 1 to 9, wherein the control unit controls the temperature of the light emitting unit to be constant.
  • the calculation unit synchronizes with the input timing signal of the rectangular wave current by the control unit, and changes with time of the wavelength of light emitted by the light emitting unit in accordance with the input of the rectangular wave current.
  • the invention according to claim 12 is the gas measuring device according to any one of claims 1 to 11, comprising a distributed feedback laser diode (DFB-LD) as a light emitting element of the light emitting section.
  • DFB-LD distributed feedback laser diode
  • the calculation unit measures an optical path distance from the light emitting unit to the light receiving unit based on a time difference between the light emission timing of the light emitting unit and the light reception timing of the light receiving unit.
  • Item 13 The gas measurement device according to any one of Items 12 above.
  • the invention according to claim 14 is the gas measuring device according to any one of claims 1 to 13, further comprising a scanning mechanism that scans the space with light emitted from the light emitting unit.
  • the invention according to claim 15 is the gas measuring device according to any one of claims 1 to 13, wherein the light emitting unit and the light receiving unit are arranged to face each other with the space interposed therebetween.
  • the present invention by inputting a current that changes sharply between two values having a drop, such as a rectangular wave current, to the light emitting unit, light emission can be performed using the response characteristics of a light emitting element such as DFB-LD.
  • the wavelength of the light emitted from the unit is changed over the absorption wavelength and non-absorption wavelength of the gas to be measured, so it is possible to detect light emission and light reception and calculate the concentration thickness product with a relatively simple configuration, and to keep the input current constant.
  • the light emission output can be kept constant, whereby the light output can be changed over the absorption wavelength and the non-absorption wavelength while the light emission output is kept constant.
  • FIG. 6 is a waveform diagram of a rectangular wave current input to a DFB-LD in an embodiment of the present invention. It is an example of the graph which shows the time change of the wavelength with respect to the input of the square wave current of DFB-LD.
  • the graph showing the light reception signal time series data shows the example at the time of non-detection.
  • the graph showing the light reception signal time series data in an embodiment of the present invention shows an example at the time of detection.
  • 3B is a graph showing received light signal time-series data in the embodiment of the present invention, and is a partially enlarged view of FIG. 3B.
  • 1 is a configuration block diagram of a gas measuring device according to an embodiment of the present invention. It is an example of a graph showing reference received light signal time series data in one embodiment of the present invention. It is a graph of an example showing the light reception signal time series data in one embodiment of the present invention. It is a block diagram of the configuration of the apparatus divided into a light projecting unit and a light receiving unit according to another embodiment of the present invention. In one Embodiment of this invention, the graph showing the light reception signal time series data shows the example at the time of non-detection.
  • the graph showing the light reception signal time series data in an embodiment of the present invention shows an example at the time of detection.
  • the graph showing the light reception signal time-series data in an embodiment of the present invention shows an example at the time of measurement error. It is a schematic diagram explaining the outline of the distance measurement principle utilized in one Embodiment of this invention.
  • the absorption wavelength of the measurement target gas is set within this wavelength change range.
  • received light signal time-series data as shown in FIG. 3A or FIG. 3B is obtained.
  • FIG. 3A shows a case where there is no measurement target gas in the measurement target space, and a substantially rectangular waveform is obtained.
  • light having an absorption wavelength is absorbed according to its concentration thickness product. Therefore, as shown in FIG. 3B, a negative peak a1 occurs on each top surface of one rectangular portion a.
  • the concentration thickness product of the measurement target gas is determined by the relativity between the negative peak a1 and the positive peak a2 or a3. It can be calculated. For example, as shown in FIG. 3C, the concentration thickness product of the measurement target gas is calculated based on the difference between the light reception signal of the negative peak a1 and the light reception signal of the positive peak a2.
  • the response characteristic of the wavelength change when a steep current change is added to the input current of the light emitting element as described above also depends on the temperature as shown in FIG. As shown in FIG. 4, since the timing of crossing the absorption wavelength ⁇ 1 varies depending on the temperature, it is preferable to keep the temperature of the light emitting element constant.
  • FIG. 5 shows a configuration diagram of an example of a gas measuring apparatus according to the present invention.
  • the gas measurement device 100 includes a light emitting unit 102 that emits light (measurement light 101) for detecting the measurement target gas G1, a control unit 103 that controls light emission of the light emitting unit 102, and a light emitting unit.
  • a light receiving unit 104 that receives light (reflected by the reflector R1) that has emitted light 102 and passed through the measurement target space S1 and a calculation unit 105 that processes the signal V1 received by the light receiving unit 104 are provided.
  • the gas measuring apparatus 100 includes a reference 106 indicating the light absorption wavelength of the measurement target gas, and a reference light receiving unit 107 that receives light emitted from the light emitting unit 102 and passed through the reference 106. Further, the gas measuring apparatus 100 includes a beam splitter 109 that distributes the light emitted from the light emitting unit 102 to the measuring light 101 and the light 108 for reference 106, an amplifier 110 that amplifies the detection value of the light receiving unit 104, and a reference light receiving unit. An amplifier 111 that amplifies the detection value 107, an amplifier 110, an AD converter 112 that AD converts each output signal of the amplifier 111, and the like are provided.
  • the light emitting unit 102 includes a distributed feedback laser diode (DFB-LD) as a light emitting element.
  • the calculation unit 105 obtains light reception signal time-series data from the AD converter 112 over the absorption wavelength and non-absorption wavelength of the gas G1 received by the light receiving unit 104.
  • the computing unit 105 obtains, from the AD converter 112, reference received light signal time-series data over the absorption wavelength and non-absorption wavelength of the gas G1 received by the reference light receiving unit 107.
  • the reference 106 is another substance or structure that responds at the same wavelength as the wavelength to which the measurement object itself or the measurement object reacts.
  • a gas cell containing a substance to be measured can be used as the reference 106.
  • the control unit 103 obtains feedback of the light receiving signal of the reference light receiving unit 107 and controls the current control unit 113 so that the reference light receiving signal time-series data has a negative peak a1. By inputting the current, a change over the absorption wavelength and the non-absorption wavelength of the measurement target gas G1 is given to the wavelength of the light emitted from the light emitting unit 102. Meanwhile, the control unit 103 controls the temperature control unit 114 to keep the temperature of the light emitting unit 102 constant.
  • the temperature control unit 114 includes a temperature control element such as a Peltier element.
  • the calculation unit 105 is based on the light reception signal of the absorption wavelength light received by the light reception unit 104 and the light reception signal of the light of the non-absorption wavelength (light reception signal time-series data). ) Is calculated.
  • Each functional block (arithmetic unit 105, control unit 103, temperature control unit 114, and current control unit 113) is, for example, a CPU (Central Processing Unit) ROM (Read Only Memory), RAM (Random Access Memory), external storage This is realized by referring to a control program and various data stored in a device (for example, a flash memory or a hard disk). However, some or all of the functional blocks may be realized by processing by a DSP (Digital Signal Processor) instead of or by processing by the CPU. Similarly, a part or all of each functional block may be realized by processing by a dedicated hardware circuit instead of or together with processing by software. An example of the calculation method of the calculation unit 105 is given below.
  • the concentration of the measurement target gas based on the difference V ( ⁇ 2) / V ( ⁇ 1) between the light reception signal V ( ⁇ 2) of the negative peak a1 and the light reception signal V ( ⁇ 1) of the positive peak a2.
  • the thickness product is calculated.
  • the light reception signal V ( ⁇ 1) corresponds to the light reception signal of the light having the absorption wavelength ⁇ 1 received by the light reception unit 104
  • the light reception signal V ( ⁇ 2) corresponds to the light reception signal of the light of the non-absorption wavelength ⁇ 2 received by the light reception unit 104. From this, the concentration-thickness product is calculated in the same manner as the conventional differential absorption method (DIAL, DOAS).
  • the method of calculating the concentration thickness product from the signal obtained from the difference between the signal of the absorption band to be measured and the signal of the non-absorption band based on Lambert Beer's law as follows.
  • the measurement target gas G1 exists on the optical path of the measurement light 101.
  • the intensity of the laser beam having the absorption wavelength ⁇ 1 is expressed by the following equation 1 of Lambert-Beer as follows:
  • the laser light with the non-absorption wavelength ⁇ 2 has a lower absorption rate and transmits better than the laser light with the absorption wavelength ⁇ 1, even if the measurement target gas G1 is generated during the passage of the laser light. Therefore, it can be assumed that the intensity of the laser beam is hardly affected even if the measurement target gas G1 is present during the passage of the laser beam. Therefore, it is considered that the difference in the intensity of the laser beam between the transmitting side and the receiving side with respect to each laser beam is generated according to the concentration thickness product of the measurement target gas G1.
  • the above processing is basic, but the simplest processing system can be configured as follows.
  • the laser light having the absorption wavelength ⁇ 1 is absorbed by the measurement target gas G1, and the intensity It1 of the weakened laser light is detected.
  • the laser light having the non-absorption wavelength ⁇ 2 is slightly absorbed by the measurement target gas G1 and weakened.
  • the intensity It2 of the laser beam is detected.
  • Ii2 ⁇ It2 holds when there is no significant difference between the intensity on the transmission side and the intensity on the reception side (when the scattering coefficient is approximately 1).
  • the arithmetic unit 105 synchronizes with the input timing signal of the rectangular wave current by the control unit 103 and the light emitted from the light emitting unit 102 in accordance with the input of the rectangular wave current as shown in FIG. It is preferable that it is possible to refer to the time change characteristic data of the wavelengths.
  • the input of the rectangular wave current and the acquisition of the received light signal are executed a plurality of times during a predetermined time, and the average value is calculated based on the received light signals for a plurality of times corresponding to all or a part thereof, for example. For example, the concentration-thickness product may be calculated.
  • the calculation unit 105 integrates the reference light reception signal time-series data in an absorption line light reception period t1 for receiving light having an absorption wavelength. For example, as shown in FIG. 6A, an area corresponding to the drop of the graph is set as a calculation target, and an integral value is obtained. This is referred to as “reference absorption band integral value Ar”. Further, as shown in FIG. 6A, the arithmetic unit 105 integrates the reference light reception signal time-series data in a non-absorption line light reception period t2 for receiving light of a non-absorption wavelength, and obtains an integral value. This is referred to as “reference non-absorption band integral value Nr”.
  • the calculation unit 105 integrates the light reception signal time-series data in an absorption line light reception period t3 in which light having an absorption wavelength is received.
  • the area corresponding to the drop of the graph is set as a calculation target, and an integral value is obtained. This is defined as “measurement target absorption band integral value As”.
  • the arithmetic unit 105 integrates the received light signal time-series data in a non-absorbing line light receiving period t4 for receiving light having a non-absorbing wavelength to obtain an integrated value. This is defined as “measurement target non-absorption band integral value Ns”.
  • the computing unit 105 calculates the concentration / thickness product of the measurement target gas G ⁇ b> 1 based on the values Ar, Nr, As, Ns and the concentration / thickness product of the reference 106.
  • the input of the rectangular wave current and the acquisition of the light reception signal are executed a plurality of times during a predetermined time, and based on the light reception signals for a plurality of times corresponding to all or a part thereof, for example, the average
  • the concentration / thickness product may be calculated by calculating a value.
  • the light emitting unit 102 is not limited to the device form that receives the reflected light from the reflector R1 as shown in FIG. It may be an apparatus in which the light receiving unit 104 is disposed so as to face the measurement target space S1.
  • a scanning mechanism 115 that scans the measurement target space S ⁇ b> 1 with light emitted from the light emitting unit 102 (measurement light 101) may be provided.
  • the scanning mechanism 115 includes a mirror 115a that reflects the measurement light 101 that is emitted and received, and a drive unit 115b that rotationally drives the mirror 115a.
  • the drive unit 115 b includes an actuator (motor) that rotates the mirror 115 a and a drive circuit thereof, and rotates the mirror 115 a based on a control signal from the control unit 103.
  • the scanning mechanism 115 can measure a one-dimensional and two-dimensional distribution of density thickness products.
  • FIG. 8A shows a normal case without light absorption by gas
  • FIG. 8B shows a normal case with light absorption by gas.
  • the received light intensity at the negative peak a1 due to light absorption of the gas can vary depending on the gas concentration thickness product.
  • the amount of change at a position other than the absorption line position a1 on the time axis does not change greatly depending on the presence or absence of gas and the concentration thickness product. If there is a significant waveform disturbance at a position on the time axis (for example, a4 in FIG. 8C) that does not vary greatly depending on the presence / absence of the gas and the concentration / thickness product, the environment other than the measurement target gas G1 at the measurement light emission destination Since there is a high possibility of wavelength disturbance due to factors or the like, the measurement result of the measurement target gas G1 is also unreliable.
  • the calculation unit 105 determines that the measurement error has occurred when the amount of change exceeds a specified value.
  • the principle of distance measurement is based on the TOF method (Time Of Flight). As schematically shown in FIG. 9, the distance L between the gas measuring device 100 and the reflector R1 (received from the light emitting unit 102) is received based on the time ⁇ until the emitted light is reflected by the reflector R1 and returns. 2L) for the optical path distance to the unit 104 is measured by the following equation.
  • the calculation unit 105 measures the optical path distance from the light emitting unit 102 to the light receiving unit 104 based on the time difference ⁇ between the light emission timing of the light emitting unit 102 and the light reception timing of the light receiving unit 104.
  • 2L corresponds to the distance across the space S1 in the above formula.
  • the “concentration thickness product” per unit length of the measurement target gas G1 that is, the concentration (average concentration) can be calculated based on the distance measured each time or the known distance.
  • the “concentration thickness product” is converted into the “concentration thickness product” per unit length, that is, the concentration (average concentration). You may calculate by a value. Although it is theoretically possible even with the 2f method, the wavelength needs to be modulated in the vicinity of the absorption line, so that the amplitude is very small and distance measurement becomes difficult. On the other hand, since pulse emission is possible according to the present invention, unlike the 2f detection method, if the circuit has a clock function, the distance can be measured by one emission, and the circuit configuration can be easily measured. realizable.
  • the light emitting unit by inputting the current that changes sharply between two values having a drop to the light emitting unit 102, the light emitting unit can be used by utilizing the response characteristics of the DFB-LD. Since the change over the absorption wavelength and non-absorption wavelength of the measurement target gas G1 is given to the wavelength of the light emitted by the light 102, it is possible to detect light emission and light reception and to calculate the concentration thickness product with a relatively simple configuration.
  • the light emission output can be kept constant by keeping the light emission constant, and the light output can be changed over the absorption wavelength and the non-absorption wavelength while the light emission output is kept constant.
  • the apparatus configuration is as simple as or better than the 2f detection method, and the optical path distance can be measured.
  • the absorption wavelength and non-absorption wavelength can be oscillated only by driving control of the laser light source, and the measurement can be performed with one detector. Therefore, the calculation of the gas concentration / thickness product can be realized with a very simple configuration.
  • pulsed light emission is advantageous in improving measurable distance and SN because it can output with high power while maintaining eye safety state compared to CW light emission.
  • S / N can be improved by calculating not only for one rectangular part a but also for a plurality of continuous rectangular parts a and calculating a measurement result based on the calculation result. . At this time, the S / N can be further improved by excluding the rectangular portion a determined as an error from the calculation target.
  • the present invention can be used for gas measurement and gas measurement devices.

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Abstract

Provided is a gas measuring device capable of emitting light and receiving and detecting light, and capable of calculating a density-thickness product, using a relatively simple configuration, and with which a wavelength can be varied and output across absorption wavelengths and non-absorption wavelengths, with the emitted light output kept constant. A gas measuring device 100 is provided with a light emitting unit 102 which emits light for detecting a gas to be measured, a control unit 103, a light receiving unit 104, and an arithmetic logic unit 105 which processes a signal received by the light receiving unit. The gas measuring device 100 calculates a density-thickness product of a gas to be measured G1 in a space S1. The control unit inputs a steeply varying electric current into the light emitting unit in order to cause the wavelength of the light emitted by the light emitting unit to vary across absorption wavelengths and non-absorption wavelengths of the gas to be measured. The arithmetic logic unit calculates the density-thickness product of the gas to be measured, on the basis of a light-reception signal of light having an absorption wavelength, and a light-reception signal of light having a non-absorption wavelength, received by the light receiving unit.

Description

ガス測定装置Gas measuring device
　本発明は、ガス測定装置に関する。 The present invention relates to a gas measuring device.
　従来の濃度厚み積を算出するガス測定装置としては、吸収波長と非吸収波長の２波長の受光信号強度の差分を取り濃度厚み積を求める差分吸収法（DIAL,DOAS)によるものと、ガス吸収線を中心に基本波fで変調し、２倍波２ｆとの受光信号比により濃度厚み積を求める２ｆ検波方式によるものとが挙げられる。
　前者は、直接差分による演算で、濃度厚み積を算出する演算処理自体は簡易であり、距離の測定も可能だが、２波長を出射するために、発光周期を遅くする、レーザーダイオードを２個用いるなど複雑な処理、装置構成が必要である。
　後者は、微小な信号変化を特定周波数の出力を取り出し演算することにより、高感度に測定が可能で、非常にコンパクトな設計が可能な技術である。しかし濃度厚み積を算出する演算が複雑になり、距離測定も困難となり、発光周期の高速化も難しい。
　また、両者とも波長を測定対象の吸収波長位置に一定に保つことが非常に難しいほか、レーザーダイオードの出力に依存し、波長が変わるため、測定中のレーザーパワーを一定にすることも難しい。波長は温度と入力電流により決まるため、ハイパワーで所望の波長を出力することにも制限が生じる。 The conventional gas thickness measurement device for calculating the concentration / thickness product is based on the difference absorption method (DIAL, DOAS) for calculating the concentration / thickness product by taking the difference between the two received light signal intensity of absorption wavelength and non-absorption wavelength. It is possible to use a 2f detection method that modulates with a fundamental wave f centering on a line and obtains a concentration thickness product based on a received light signal ratio with the second harmonic wave 2f.
The former is a calculation based on direct difference, and the calculation process itself for calculating the concentration-thickness product is simple and the distance can be measured. However, in order to emit two wavelengths, two laser diodes are used that slow the light emission period. Such complicated processing and device configuration are required.
The latter is a technique that can measure a very small signal change by taking out an output of a specific frequency and calculating it with high sensitivity and enabling a very compact design. However, the calculation for calculating the concentration-thickness product is complicated, distance measurement is difficult, and it is difficult to speed up the light emission cycle.
In both cases, it is very difficult to keep the wavelength constant at the absorption wavelength position of the measurement object, and the wavelength changes depending on the output of the laser diode, so it is difficult to keep the laser power during measurement constant. Since the wavelength is determined by the temperature and the input current, there is a limit to outputting a desired wavelength with high power.
　特許文献１には、一つのレーザー光源と、ＯＰＯ(光パラメトリック発振）と、エタロン板とを用いてガスの吸収波長、非吸収波長の２波長のレーザー光を外部へ照射し、反射光をダイクロイックミラーで分光し、それぞれの波長に対応した検出器の出力より測定対象の濃度厚み積を算出する発明が記載さている。 Patent Document 1 irradiates laser light of two wavelengths, gas absorption wavelength and non-absorption wavelength, using a single laser light source, OPO (Optical Parametric Oscillation), and etalon plate, and the reflected light is dichroic. An invention is described in which the concentration-thickness product of the measurement object is calculated from the output of the detector corresponding to each wavelength by performing spectroscopy with a mirror.
特開２００１－１５９６０４号公報JP 2001-159604 A
　しかし、特許文献１に記載の発明にあっては、レーザー光源が一つで済むものの、ＯＰＯ、さらにはダイクロイックミラー、エタロンフィルタ、２種類の検出器を用いるなど、全体としては必要な構成部品も多く複雑化する。 However, in the invention described in Patent Document 1, although only one laser light source is required, OPO, further dichroic mirror, etalon filter, and two types of detectors are used as a whole. A lot of complexity.
　本発明は以上の従来技術における問題に鑑みてなされたものであって、比較的簡単な構成で発光及び受光検出、濃度厚み積の算出が可能であり、発光の出力を一定に保った状態で吸収波長及び非吸収波長に亘り波長を変えて出力することができるガス測定装置を提供することを課題とする。 The present invention has been made in view of the above-described problems in the prior art, and is capable of detecting light emission and light reception and calculating the concentration-thickness product with a relatively simple configuration, while keeping the light emission output constant. It is an object of the present invention to provide a gas measuring device that can output by changing the wavelength over an absorption wavelength and a non-absorption wavelength.
　以上の課題を解決するための請求項１記載の発明は、測定対象ガスを検出するための光を発光する発光部と、
前記発光部の発光を制御する制御部と、
前記発光部が発光し空間を経た光を受光する受光部と、
前記受光部が受光した信号を処理する演算部と、を備えて前記空間における測定対象ガスの濃度厚み積を算出するガス測定装置であって、
前記制御部は、前記発光部に急峻に変化する電流を入力することで、前記発光部が発光する光の波長に前記測定対象ガスの吸収波長及び非吸収波長に亘る変化を与え、
前記演算部は、前記受光部が受光した前記吸収波長の光の受光信号及び前記非吸収波長の光の受光信号に基づき、前記測定対象ガスの濃度厚み積を算出するガス測定装置である。 The invention according to claim 1 for solving the above-described problems includes a light emitting unit that emits light for detecting a measurement target gas;
A control unit for controlling light emission of the light emitting unit;
A light receiving portion for receiving light emitted from the light emitting portion and passing through the space;
A gas measurement device that calculates a concentration / thickness product of a measurement target gas in the space, and a calculation unit that processes a signal received by the light receiving unit,
The control unit gives a change over the absorption wavelength and non-absorption wavelength of the measurement target gas to the wavelength of light emitted by the light emitting unit by inputting a current that changes sharply to the light emitting unit,
The calculation unit is a gas measurement device that calculates a concentration thickness product of the measurement target gas based on a light reception signal of the light having the absorption wavelength and a light reception signal of the light having the non-absorption wavelength received by the light reception unit.
　請求項２記載の発明は、前記演算部は、前記受光部が受光した前記吸収波長の光の受光信号と、前記非吸収波長の光の受光信号との差分に基づき測定対象ガスの濃度厚み積を算出する請求項１に記載のガス測定装置である。 According to a second aspect of the present invention, the calculation unit is configured to calculate a concentration thickness product of a measurement target gas based on a difference between a light reception signal of the absorption wavelength light received by the light reception unit and a light reception signal of the non-absorption wavelength light. It is a gas measuring device of Claim 1 which computes.
　請求項３記載の発明は、前記演算部は、前記受光部が受光した前記吸収波長及び前記非吸収波長に亘る受光信号時系列データを得て、当該受光信号時系列データに基づき、前記測定対象ガスの濃度厚み積を算出する請求項１に記載のガス測定装置である。 According to a third aspect of the present invention, the calculation unit obtains light reception signal time series data over the absorption wavelength and the non-absorption wavelength received by the light reception unit, and based on the light reception signal time series data, the measurement target The gas measuring device according to claim 1, wherein a gas concentration / thickness product is calculated.
　請求項４記載の発明は、前記演算部は、受光信号時系列データを、前記吸収波長の光を受光する吸収線受光期間で積分し当該積分値に基づき、前記測定対象ガスの濃度厚み積を算出する請求項３に記載のガス測定装置である。 According to a fourth aspect of the present invention, the calculation unit integrates the light reception signal time-series data in an absorption line light reception period for receiving light of the absorption wavelength, and calculates the concentration thickness product of the measurement target gas based on the integration value. The gas measuring device according to claim 3 to be calculated.
　請求項５記載の発明は、前記演算部は、前記非吸収波長の光を受光する非吸収線受光期間で積分し当該積分値と、前記吸収線受光期間の積分値とに基づき、前記測定対象ガスの濃度厚み積を算出する請求項４に記載のガス測定装置である。 According to a fifth aspect of the present invention, the calculation unit integrates in a non-absorption line light receiving period for receiving the light of the non-absorption wavelength, and based on the integration value and the integration value of the absorption line light reception period, the measurement object It is a gas measuring device of Claim 4 which calculates the concentration thickness product of gas.
　請求項６記載の発明は、前記演算部は、前記非吸収波長の光の受光信号に基づき、測定エラーを判定する請求項１から請求項４のうちいずれか一に記載のガス測定装置である。 A sixth aspect of the present invention is the gas measuring device according to any one of the first to fourth aspects, wherein the calculation unit determines a measurement error based on a light reception signal of the light having the non-absorbing wavelength. .
　請求項７記載の発明は、前記測定対象ガスの光吸収波長を示すリファレンスと、前記発光部が発光し前記リファレンスを経た光を受光するリファレンス受光部と、を備え、
前記制御部は、前記リファレンス受光部の受光信号のフィードバックを得て、前記発光部に矩形波電流を入力することで、前記発光部が発光する光の波長に前記測定対象ガスの吸収波長及び非吸収波長に亘る変化を与える請求項１に記載のガス測定装置である。 The invention according to claim 7 includes a reference indicating a light absorption wavelength of the measurement target gas, and a reference light receiving unit that receives the light emitted from the light emitting unit and passed through the reference,
The control unit obtains feedback of the light receiving signal of the reference light receiving unit and inputs a rectangular wave current to the light emitting unit, so that the absorption wavelength of the measurement target gas and the non-wavelength of light emitted from the light emitting unit are increased. The gas measuring device according to claim 1, wherein the gas measuring device gives a change over an absorption wavelength.
　請求項８記載の発明は、前記演算部は、前記受光部が受光した前記吸収波長の光の受光信号と、前記リファレンス受光部が受光した前記吸収波長の光の受光信号とに基づき測定対象ガスの濃度厚み積を算出する請求項７に記載のガス測定装置である。 According to an eighth aspect of the present invention, the calculation unit is configured to measure a measurement target gas based on a light reception signal of the light having the absorption wavelength received by the light reception unit and a light reception signal of the light having the absorption wavelength received by the reference light reception unit. The gas measuring device according to claim 7, wherein the concentration-thickness product is calculated.
　請求項９記載の発明は、前記演算部は、前記受光部が受光した前記吸収波長及び前記非吸収波長に亘る受光信号時系列データ、及び前記リファレンス受光部が受光した前記吸収波長及び前記非吸収波長に亘るリファレンス受光信号時系列データを得て、当該受光信号時系列データと当該リファレンス受光信号時系列データとに基づき、前記測定対象ガスの濃度厚み積を算出する請求項７に記載のガス測定装置である。 According to a ninth aspect of the present invention, the calculation unit includes: the absorption wavelength received by the light receiving unit and the light reception signal time-series data over the non-absorption wavelength; and the absorption wavelength and the non-absorption received by the reference light receiving unit. 8. The gas measurement according to claim 7, wherein reference light reception signal time-series data over a wavelength is obtained, and a concentration thickness product of the measurement target gas is calculated based on the light reception signal time-series data and the reference light reception signal time-series data. Device.
　請求項１０記載の発明は、前記制御部は、前記発光部の温度を一定に制御する請求項１から請求項９のうちいずれか一に記載のガス測定装置である。 The invention according to claim 10 is the gas measuring device according to any one of claims 1 to 9, wherein the control unit controls the temperature of the light emitting unit to be constant.
　請求項１１記載の発明は、前記演算部は、前記制御部による前記矩形波電流の入力タイミング信号との同期と、前記矩形波電流の入力に伴う前記発光部が発光する光の波長の時間変化特性データの参照とが可能にされた請求項１から請求項１０のうちいずれか一に記載のガス測定装置である。 According to an eleventh aspect of the present invention, the calculation unit synchronizes with the input timing signal of the rectangular wave current by the control unit, and changes with time of the wavelength of light emitted by the light emitting unit in accordance with the input of the rectangular wave current. The gas measurement device according to any one of claims 1 to 10, wherein reference to characteristic data is enabled.
　請求項１２記載の発明は、前記発光部の発光素子として分布帰還型レーザダイオード（ＤＦＢ－ＬＤ）を備える請求項１から請求項１１のうちいずれか一に記載のガス測定装置である。　 The invention according to claim 12 is the gas measuring device according to any one of claims 1 to 11, comprising a distributed feedback laser diode (DFB-LD) as a light emitting element of the light emitting section. *
　請求項１３記載の発明は、前記演算部は、前記発光部の発光タイミングと前記受光部の受光タイミングの時差に基づき、前記発光部から前記受光部までの光路距離を測定する請求項１から請求項１２のうちいずれか一に記載のガス測定装置である。 According to a thirteenth aspect of the present invention, the calculation unit measures an optical path distance from the light emitting unit to the light receiving unit based on a time difference between the light emission timing of the light emitting unit and the light reception timing of the light receiving unit. Item 13. The gas measurement device according to any one of Items 12 above.
　請求項１４記載の発明は、前記発光部が発光する光で前記空間を走査する走査機構を備える請求項１から請求項１３のうちいずれか一に記載のガス測定装置である。 The invention according to claim 14 is the gas measuring device according to any one of claims 1 to 13, further comprising a scanning mechanism that scans the space with light emitted from the light emitting unit.
　請求項１５記載の発明は、前記発光部と、前記受光部とが前記空間を挟んで対向配置される請求項１から請求項１３のうちいずれか一に記載のガス測定装置である。 The invention according to claim 15 is the gas measuring device according to any one of claims 1 to 13, wherein the light emitting unit and the light receiving unit are arranged to face each other with the space interposed therebetween.
　本発明によれば、発光部に、矩形波電流等の落差のある２つの値の間で急峻に変化する電流を入力することで、ＤＦＢ－ＬＤなど発光素子の応答特性を利用して、発光部が発光する光の波長に測定対象ガスの吸収波長及び非吸収波長に亘る変化を与えるので、比較的簡単な構成で発光及び受光検出、濃度厚み積の算出が可能であり、入力電流を一定にすることで発光の出力を一定に保つことができ、これにより発光の出力を一定に保った状態で吸収波長及び非吸収波長に亘り波長を変えて出力することができる。 According to the present invention, by inputting a current that changes sharply between two values having a drop, such as a rectangular wave current, to the light emitting unit, light emission can be performed using the response characteristics of a light emitting element such as DFB-LD. The wavelength of the light emitted from the unit is changed over the absorption wavelength and non-absorption wavelength of the gas to be measured, so it is possible to detect light emission and light reception and calculate the concentration thickness product with a relatively simple configuration, and to keep the input current constant. Thus, the light emission output can be kept constant, whereby the light output can be changed over the absorption wavelength and the non-absorption wavelength while the light emission output is kept constant.
本発明の一実施形態においてＤＦＢ－ＬＤに入力する矩形波電流の波形図である。FIG. 6 is a waveform diagram of a rectangular wave current input to a DFB-LD in an embodiment of the present invention. ＤＦＢ－ＬＤの矩形波電流の入力に対する波長の時間変化を示す一例のグラフである。It is an example of the graph which shows the time change of the wavelength with respect to the input of the square wave current of DFB-LD. 本発明の一実施形態において受光信号時系列データを表すグラフで、非検出時の例を示す。In one Embodiment of this invention, the graph showing the light reception signal time series data shows the example at the time of non-detection. 本発明の一実施形態において受光信号時系列データを表すグラフで、検出時の例を示す。The graph showing the light reception signal time series data in an embodiment of the present invention shows an example at the time of detection. 本発明の一実施形態において受光信号時系列データを表すグラフで、図３Ｂの部分拡大図である。3B is a graph showing received light signal time-series data in the embodiment of the present invention, and is a partially enlarged view of FIG. 3B. FIG. 発光素子の入力電流の変化に対する波長の変化の温度特性を示すグラフである。It is a graph which shows the temperature characteristic of the change of the wavelength with respect to the change of the input current of a light emitting element. 本発明の一実施形態に係るガス測定装置の構成ブロック図である。1 is a configuration block diagram of a gas measuring device according to an embodiment of the present invention. 本発明の一実施形態においてリファレンス受光信号時系列データを表す一例のグラフである。It is an example of a graph showing reference received light signal time series data in one embodiment of the present invention. 本発明の一実施形態において受光信号時系列データを表す一例のグラフである。It is a graph of an example showing the light reception signal time series data in one embodiment of the present invention. 本発明の他の一実施形態に係る投光ユニットと受光ユニットに分かれた装置形態の構成ブロック図である。It is a block diagram of the configuration of the apparatus divided into a light projecting unit and a light receiving unit according to another embodiment of the present invention. 本発明の一実施形態において受光信号時系列データを表すグラフで、非検出時の例を示す。In one Embodiment of this invention, the graph showing the light reception signal time series data shows the example at the time of non-detection. 本発明の一実施形態において受光信号時系列データを表すグラフで、検出時の例を示す。The graph showing the light reception signal time series data in an embodiment of the present invention shows an example at the time of detection. 本発明の一実施形態において受光信号時系列データを表すグラフで、測定エラー時の例を示す。The graph showing the light reception signal time-series data in an embodiment of the present invention shows an example at the time of measurement error. 本発明の一実施形態において利用する距離測定原理の概略を説明する模式図である。It is a schematic diagram explaining the outline of the distance measurement principle utilized in one Embodiment of this invention.
　以下に本発明の一実施形態につき図面を参照して説明する。以下は本発明の一実施形態であって本発明を限定するものではない。 Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.
　ＤＦＢ－ＬＤに急峻な電流変化を加えた際に、発熱量の増加に伴い活性層の屈折率が上昇し、波長が長波長側にμsからｍｓオーダーで非線形的に変化することが知られている。本発明はその波長変化により、測定対象ガスの吸収波長及び非吸収波長に亘る変化を与える。ＤＦＢ－ＬＤに急峻な電流変化を加えるため、図１に示すような矩形波電流を入力する。なお、この矩形波電流を一定にすることで、発光の出力を一定に保つことができる。
　ＤＦＢ－ＬＤに図１の矩形波電流を入力すると、図２に示すようにＤＦＢ－ＬＤの出射光の波長が変化する。この波長変化範囲に測定対象ガスの吸収波長があるようにする。
　このように波長変化するＤＦＢ－ＬＤの出射光を、測定対象空間を経て受光すると、図３Ａ又は図３Ｂに示すような受光信号時系列データが得られる。図３Ａは、測定対象空間に測定対象ガスが無かった場合であり略矩形状の波形となるが、測定対象空間に測定対象ガスがあるとその濃度厚み積に応じて吸収波長の光が吸収されるので図３Ｂに示すように１つの矩形部ａの天面のそれぞれに負のピークａ１が生じる。
　負のピークａ１に隣接する正のピークａ２，ａ３は、非吸収波長の受光信号であるので、負のピークａ１と、正のピークａ２又はａ３との相対性により測定対象ガスの濃度厚み積を算出可能である。例えば、図３Ｃに示すように、負のピークａ１の受光信号と、正のピークａ２の受光信号との差分に基づき測定対象ガスの濃度厚み積を算出する。 It is known that when a steep current change is applied to the DFB-LD, the refractive index of the active layer increases as the amount of heat generation increases, and the wavelength changes nonlinearly from μs to ms order on the long wavelength side. Yes. In the present invention, the change over the absorption wavelength and the non-absorption wavelength of the measurement target gas is given by the wavelength change. In order to apply a steep current change to the DFB-LD, a rectangular wave current as shown in FIG. 1 is input. Note that the output of light emission can be kept constant by making the rectangular wave current constant.
When the rectangular wave current of FIG. 1 is input to the DFB-LD, the wavelength of the emitted light of the DFB-LD changes as shown in FIG. The absorption wavelength of the measurement target gas is set within this wavelength change range.
When the emitted light of the DFB-LD whose wavelength changes in this way is received through the measurement target space, received light signal time-series data as shown in FIG. 3A or FIG. 3B is obtained. FIG. 3A shows a case where there is no measurement target gas in the measurement target space, and a substantially rectangular waveform is obtained. However, when the measurement target gas exists in the measurement target space, light having an absorption wavelength is absorbed according to its concentration thickness product. Therefore, as shown in FIG. 3B, a negative peak a1 occurs on each top surface of one rectangular portion a.
Since the positive peaks a2 and a3 adjacent to the negative peak a1 are light-receiving signals having non-absorption wavelengths, the concentration thickness product of the measurement target gas is determined by the relativity between the negative peak a1 and the positive peak a2 or a3. It can be calculated. For example, as shown in FIG. 3C, the concentration thickness product of the measurement target gas is calculated based on the difference between the light reception signal of the negative peak a1 and the light reception signal of the positive peak a2.
　以上のような発光素子の入力電流に急峻な電流変化を加えたときの波長変化の応答特性は、図４に示すように温度にも依存する。図４に示すように吸収波長λ１を横切るタイミングが温度によって異なってしまうため、発光素子の温度を一定に保つことが好ましい。 The response characteristic of the wavelength change when a steep current change is added to the input current of the light emitting element as described above also depends on the temperature as shown in FIG. As shown in FIG. 4, since the timing of crossing the absorption wavelength λ1 varies depending on the temperature, it is preferable to keep the temperature of the light emitting element constant.
　図５に本発明によるガス測定装置の一例の構成図を示す。
　図５に示すようにガス測定装置１００は、測定対象ガスＧ１を検出するための光（測定光１０１）を発光する発光部１０２と、発光部１０２の発光を制御する制御部１０３と、発光部１０２が発光し測定対象空間Ｓ１を経た光（反射物Ｒ１で反射）を受光する受光部１０４と、受光部１０４が受光した信号Ｖ１を処理する演算部１０５と、を備える。
　また、ガス測定装置１００は、測定対象ガスの光吸収波長を示すリファレンス１０６と、発光部１０２が発光しリファレンス１０６を経た光を受光するリファレンス受光部１０７とを備える。
　さらにガス測定装置１００は、発光部１０２が発光した光を測定光１０１と、リファレンス１０６参照用の光１０８とに分配するビームスプリッター１０９、受光部１０４の検出値を増幅する増幅器１１０、リファレンス受光部１０７の検出値を増幅する増幅器１１１、増幅器１１０及び増幅器１１１の各出力信号をＡＤ変換するＡＤ変換器１１２等を備える。
　発光部１０２は、発光素子として分布帰還型レーザダイオード（ＤＦＢ－ＬＤ）を備える。
　演算部１０５は、ＡＤ変換器１１２から、受光部１０４が受光したガスＧ１の吸収波長及び非吸収波長に亘る受光信号時系列データを得る。
　演算部１０５は、ＡＤ変換器１１２から、リファレンス受光部１０７が受光したガスＧ１の吸収波長及び非吸収波長に亘るリファレンス受光信号時系列データを得る。 FIG. 5 shows a configuration diagram of an example of a gas measuring apparatus according to the present invention.
As shown in FIG. 5, the gas measurement device 100 includes a light emitting unit 102 that emits light (measurement light 101) for detecting the measurement target gas G1, a control unit 103 that controls light emission of the light emitting unit 102, and a light emitting unit. A light receiving unit 104 that receives light (reflected by the reflector R1) that has emitted light 102 and passed through the measurement target space S1 and a calculation unit 105 that processes the signal V1 received by the light receiving unit 104 are provided.
The gas measuring apparatus 100 includes a reference 106 indicating the light absorption wavelength of the measurement target gas, and a reference light receiving unit 107 that receives light emitted from the light emitting unit 102 and passed through the reference 106.
Further, the gas measuring apparatus 100 includes a beam splitter 109 that distributes the light emitted from the light emitting unit 102 to the measuring light 101 and the light 108 for reference 106, an amplifier 110 that amplifies the detection value of the light receiving unit 104, and a reference light receiving unit. An amplifier 111 that amplifies the detection value 107, an amplifier 110, an AD converter 112 that AD converts each output signal of the amplifier 111, and the like are provided.
The light emitting unit 102 includes a distributed feedback laser diode (DFB-LD) as a light emitting element.
The calculation unit 105 obtains light reception signal time-series data from the AD converter 112 over the absorption wavelength and non-absorption wavelength of the gas G1 received by the light receiving unit 104.
The computing unit 105 obtains, from the AD converter 112, reference received light signal time-series data over the absorption wavelength and non-absorption wavelength of the gas G1 received by the reference light receiving unit 107.
　リファレンス１０６は、測定対象そのものや測定対象が反応する波長とおなじ波長で応答する別の物質や構造物とされる。例えばリファレンス１０６としては、測定対象の物質を封じ込めたガスセルを使用できる。
　リファレンス受光信号時系列データに確実に負のピークａ１があるように、制御部１０３は、リファレンス受光部１０７の受光信号のフィードバックを得て、電流制御部１１３を制御して発光部１０２に矩形波電流を入力することで、発光部１０２が発光する光の波長に測定対象ガスＧ１の吸収波長及び非吸収波長に亘る変化を与える。
　その間、制御部１０３は温度制御部１１４を制御して発光部１０２の温度を一定に保つ。温度制御部１１４にペルチェ素子などの温調素子が含まれる。 The reference 106 is another substance or structure that responds at the same wavelength as the wavelength to which the measurement object itself or the measurement object reacts. For example, as the reference 106, a gas cell containing a substance to be measured can be used.
The control unit 103 obtains feedback of the light receiving signal of the reference light receiving unit 107 and controls the current control unit 113 so that the reference light receiving signal time-series data has a negative peak a1. By inputting the current, a change over the absorption wavelength and the non-absorption wavelength of the measurement target gas G1 is given to the wavelength of the light emitted from the light emitting unit 102.
Meanwhile, the control unit 103 controls the temperature control unit 114 to keep the temperature of the light emitting unit 102 constant. The temperature control unit 114 includes a temperature control element such as a Peltier element.
　演算部１０５は、受光部１０４が受光した吸収波長の光の受光信号及び非吸収波長の光の受光信号（受光信号時系列データ）に基づき、測定対象ガスＧ１の濃度厚み積（下記ｄ・ｃ）を算出する。
　各機能ブロック（演算部１０５、制御部１０３、温度制御部１１４、及び電流制御部１１３）は、例えば、ＣＰＵ（Central Processing Unit）がＲＯＭ（Read Only Memory）、ＲＡＭ(Random Access Memory）、外部記憶装置（例えば、フラッシュメモリやハードディスク）に記憶された制御プログラムや各種データを参照することによって実現される。但し、各機能ブロックの一部又は全部は、ＣＰＵによる処理に代えて、又は、これと共に、ＤＳＰ（Digital Signal Processor）による処理によって実現されてもよい。又、同様に、各機能ブロックの一部又は全部は、ソフトウェアによる処理に代えて、又は、これと共に、専用のハードウェア回路による処理によって実現されてもよい。
　演算部１０５の算出方式の例を以下に挙げる。 The calculation unit 105 is based on the light reception signal of the absorption wavelength light received by the light reception unit 104 and the light reception signal of the light of the non-absorption wavelength (light reception signal time-series data). ) Is calculated.
Each functional block (arithmetic unit 105, control unit 103, temperature control unit 114, and current control unit 113) is, for example, a CPU (Central Processing Unit) ROM (Read Only Memory), RAM (Random Access Memory), external storage This is realized by referring to a control program and various data stored in a device (for example, a flash memory or a hard disk). However, some or all of the functional blocks may be realized by processing by a DSP (Digital Signal Processor) instead of or by processing by the CPU. Similarly, a part or all of each functional block may be realized by processing by a dedicated hardware circuit instead of or together with processing by software.
An example of the calculation method of the calculation unit 105 is given below.
（２値差分方式）
　図３Ｃに示すように、負のピークａ１の受光信号Ｖ（λ２）と、正のピークａ２の受光信号Ｖ（λ１）との差分Ｖ（λ２）／Ｖ（λ１）に基づき測定対象ガスの濃度厚み積を算出する。受光信号Ｖ（λ１）は受光部１０４が受光した吸収波長λ１の光の受光信号に相当し、受光信号Ｖ（λ２）は受光部１０４が受光した非吸収波長λ２の光の受光信号に相当するから、従来の差分吸収法（DIAL,DOAS)と同様に濃度厚み積を算出する。
　すなわち、次のようにランベルトベールの法則に基づいて測定対象の吸収帯の信号と非吸収帯の信号の差分でえられる信号から濃度厚み積を算出する方法を実施する。今、測定光１０１の光路上に測定対象ガスＧ１が存在しているものと仮定する。吸収波長λ１のレーザー光は、測定対象ガスＧ１によく吸収され、測定対象ガスＧ１中を透過した場合吸収波長λ１のレーザー光の強度は、Ｌａｍｂｅｒｔ－Ｂｅｅｒの次式１で以下のように表される。 (Binary difference method)
As shown in FIG. 3C, the concentration of the measurement target gas based on the difference V (λ2) / V (λ1) between the light reception signal V (λ2) of the negative peak a1 and the light reception signal V (λ1) of the positive peak a2. The thickness product is calculated. The light reception signal V (λ1) corresponds to the light reception signal of the light having the absorption wavelength λ1 received by the light reception unit 104, and the light reception signal V (λ2) corresponds to the light reception signal of the light of the non-absorption wavelength λ2 received by the light reception unit 104. From this, the concentration-thickness product is calculated in the same manner as the conventional differential absorption method (DIAL, DOAS).
That is, the method of calculating the concentration thickness product from the signal obtained from the difference between the signal of the absorption band to be measured and the signal of the non-absorption band based on Lambert Beer's law as follows. Now, it is assumed that the measurement target gas G1 exists on the optical path of the measurement light 101. When the laser beam having the absorption wavelength λ1 is well absorbed by the measurement target gas G1 and passes through the measurement target gas G1, the intensity of the laser beam having the absorption wavelength λ1 is expressed by the following equation 1 of Lambert-Beer as follows: The
Ｉｔ＝Ｉｉ×ｅｘｐ（－ａ・ｐ・ｄ・ｃ）×α・・・式１
ここで、 Ｉｔ：レーザー光の受信強度
Ｉｉ：レーザー光の発信強度
ａ：吸収係数（ａｔｍ-1・ｍ-1）
ｐ：気体圧力（ａｔｍ）
ｄ：レーザー光が被検出ガス中を透過する長さ（ｍ）
ｃ：測定対象ガスの濃度（ｐｐｍ）
α：背景におけるレーザー光の散乱係数
従って、測定対象ガスＧ１の濃度厚み積ｄ・ｃは吸収波長λ１のレーザー光に付いては、次式２で表される。 It = Ii × exp (−a · p · d · c) × α Equation 1
Here, It: laser beam reception intensity Ii: laser beam transmission intensity a: absorption coefficient (atm −1 · m −1 )
p: Gas pressure (atm)
d: Length of laser beam passing through the detection gas (m)
c: Measurement target gas concentration (ppm)
α: Scattering coefficient of laser light in the background Accordingly, the concentration thickness product d · c of the measurement target gas G1 is expressed by the following equation 2 for the laser light having the absorption wavelength λ1.
Figure JPOXMLDOC01-appb-M000001
ここで、各レーザー光に関する数値については、最後尾に添字の１または２を付けて表示する。
Figure JPOXMLDOC01-appb-M000001
Here, numerical values relating to each laser beam are displayed with a suffix of 1 or 2 at the end.
　一方、非吸収波長λ２のレーザー光は、測定対象ガスＧ１がレーザー光の通過の途中に発生していたとしても、吸収波長λ１のレーザー光に比較して吸収率が小さく、よく透過する。従って、レーザー光の通過途中に測定対象ガスＧ１があってもレーザー光の強度は殆ど影響を受けない場合を想定できる。そこで、各レーザー光に対する送信側と受信側のおけるレーザー光の強度の差が、測定対象ガスＧ１の濃度厚み積に応じて生じると考えるのである。以上の処理が基本であるが、最も簡単な処理系は以下の様に構成できる。ここで、吸収波長λ１のレーザー光が測定対象ガスＧ１に吸収されて、弱まったレーザー光の強度Ｉｔ1を検出し、さらに非吸収波長λ２のレーザー光が、測定対象ガスＧ１に若干吸収されて弱まったレーザー光の強度Ｉｔ2を検出する。非吸収波長λ２のレーザー光に対しては、その発信側強度、及び受信側強度に大きな差が生じない場合（散乱係数がほぼ１の場合）は、Ｉｉ2≒Ｉｔ2が成立する。さらに発信側におけるλ１、λ２のレーザー光の強度比Ｋ＝Ｉｉ1／Ｉｉ2を１とすると、Ｉｉ1＝Ｉｉ2であるから、（Ｉｉ1－Ｉｔ1）／Ｉｉ1＝（Ｉｔ2－Ｉｔ1）／Ｉｔ2となり、これを用いて、式２に適応することによりｄ・ｃを算出することができる。なお、ここで、Ｉｔ2は背景についての情報出力であり、（Ｉｔ2－Ｉｔ1）とすることによって測定対象ガスＧ１の濃度厚み積についての情報のみを出力することが可能となるのである。さらに、Ｉｔ2で除算しているのは、正規化処理である。
　以上の処理を実施するために、演算部１０５は、制御部１０３による矩形波電流の入力タイミング信号との同期と、図２に示すような矩形波電流の入力に伴う発光部１０２が発光する光の波長の時間変化特性データの参照とが可能にされていることが好ましい。
　なお、ＳＮ向上のために、矩形波電流の入力と受光信号の取得を所定時間中に複数回実行し、その全部又は一部に相当する複数回分の受光信号に基づき、例えばその平均値を算出するなどして、濃度厚み積を算出してもよい。 On the other hand, the laser light with the non-absorption wavelength λ2 has a lower absorption rate and transmits better than the laser light with the absorption wavelength λ1, even if the measurement target gas G1 is generated during the passage of the laser light. Therefore, it can be assumed that the intensity of the laser beam is hardly affected even if the measurement target gas G1 is present during the passage of the laser beam. Therefore, it is considered that the difference in the intensity of the laser beam between the transmitting side and the receiving side with respect to each laser beam is generated according to the concentration thickness product of the measurement target gas G1. The above processing is basic, but the simplest processing system can be configured as follows. Here, the laser light having the absorption wavelength λ1 is absorbed by the measurement target gas G1, and the intensity It1 of the weakened laser light is detected. Further, the laser light having the non-absorption wavelength λ2 is slightly absorbed by the measurement target gas G1 and weakened. The intensity It2 of the laser beam is detected. For a laser beam having a non-absorption wavelength λ2, Ii2≈It2 holds when there is no significant difference between the intensity on the transmission side and the intensity on the reception side (when the scattering coefficient is approximately 1). Further, assuming that the intensity ratio K = Ii1 / Ii2 of λ1 and λ2 on the transmitting side is 1, since Ii1 = Ii2, (Ii1−It1) / Ii1 = (It2−It1) / It2 is used. Thus, d · c can be calculated by applying the equation (2). Here, It2 is an information output about the background, and by setting it to (It2-It1), it is possible to output only information about the concentration thickness product of the measurement target gas G1. Further, what is divided by It2 is a normalization process.
In order to carry out the above processing, the arithmetic unit 105 synchronizes with the input timing signal of the rectangular wave current by the control unit 103 and the light emitted from the light emitting unit 102 in accordance with the input of the rectangular wave current as shown in FIG. It is preferable that it is possible to refer to the time change characteristic data of the wavelengths.
In order to improve SN, the input of the rectangular wave current and the acquisition of the received light signal are executed a plurality of times during a predetermined time, and the average value is calculated based on the received light signals for a plurality of times corresponding to all or a part thereof, for example. For example, the concentration-thickness product may be calculated.
（積分方式）
　演算部１０５は、図６Ａに示すようにリファレンス受光信号時系列データを、吸収波長の光を受光する吸収線受光期間ｔ１で積分する。例えば、図６Ａに示すようにグラフの落ち込み相当分の面積を算出対象とし、積分値を得る。これを「リファレンス吸収帯積分値Ａｒ」とする。
　また、演算部１０５は、図６Ａに示すようにリファレンス受光信号時系列データを、非吸収波長の光を受光する非吸収線受光期間ｔ２で積分し積分値を得る。これを「リファレンス非吸収帯積分値Ｎｒ」とする。
　演算部１０５は、図６Ｂに示すように受光信号時系列データを、吸収波長の光を受光する吸収線受光期間ｔ３で積分する。上記と同様に、図６Ｂに示すようにグラフの落ち込み相当分の面積を算出対象とし、積分値を得る。これを「測定対象吸収帯積分値Ａs」とする。
　また、演算部１０５は、図６Ｂに示すように受光信号時系列データを、非吸収波長の光を受光する非吸収線受光期間ｔ４で積分し積分値を得る。これを「測定対象非吸収帯積分値Ｎｓ」とする。
　演算部１０５は、各値Ａｒ，Ｎｒ，Ａs，Ｎｓとリファレンス１０６の濃度厚み積とに基づき、測定対象ガスＧ１の濃度厚み積を算出する。その算出式の一例は次のとおりである。
　（測定対象ガスＧ１の濃度厚み積）＝（リファレンスの濃度厚み積）×（Ａｒ／Ｎｒ）×（Ａs／Ｎｓ）
　上記２値差分方式よりデータ数が多くなるため、Ｓ／Ｎを向上することができる。
　なお、ここでも、ＳＮ向上のために、矩形波電流の入力と受光信号の取得を所定時間中に複数回実行し、その全部又は一部に相当する複数回分の受光信号に基づき、例えばその平均値を算出するなどして、濃度厚み積を算出してもよい。 (Integration method)
As shown in FIG. 6A, the calculation unit 105 integrates the reference light reception signal time-series data in an absorption line light reception period t1 for receiving light having an absorption wavelength. For example, as shown in FIG. 6A, an area corresponding to the drop of the graph is set as a calculation target, and an integral value is obtained. This is referred to as “reference absorption band integral value Ar”.
Further, as shown in FIG. 6A, the arithmetic unit 105 integrates the reference light reception signal time-series data in a non-absorption line light reception period t2 for receiving light of a non-absorption wavelength, and obtains an integral value. This is referred to as “reference non-absorption band integral value Nr”.
As shown in FIG. 6B, the calculation unit 105 integrates the light reception signal time-series data in an absorption line light reception period t3 in which light having an absorption wavelength is received. Similarly to the above, as shown in FIG. 6B, the area corresponding to the drop of the graph is set as a calculation target, and an integral value is obtained. This is defined as “measurement target absorption band integral value As”.
Further, as shown in FIG. 6B, the arithmetic unit 105 integrates the received light signal time-series data in a non-absorbing line light receiving period t4 for receiving light having a non-absorbing wavelength to obtain an integrated value. This is defined as “measurement target non-absorption band integral value Ns”.
The computing unit 105 calculates the concentration / thickness product of the measurement target gas G <b> 1 based on the values Ar, Nr, As, Ns and the concentration / thickness product of the reference 106. An example of the calculation formula is as follows.
(Concentration thickness product of measurement target gas G1) = (Reference concentration thickness product) × (Ar / Nr) × (As / Ns)
Since the number of data is larger than that in the binary difference method, S / N can be improved.
In this case as well, in order to improve the SN, the input of the rectangular wave current and the acquisition of the light reception signal are executed a plurality of times during a predetermined time, and based on the light reception signals for a plurality of times corresponding to all or a part thereof, for example, the average The concentration / thickness product may be calculated by calculating a value.
　なお、リファレンス１０６に基づくデータを演算に使用しない場合は、これを得るための要素は不要である。また、図５に示すような反射物Ｒ１からの反射光を受光する装置形態に限らず、図７に示すような投光ユニット１２０と、受光ユニット１２１に分かれた装置形態など、発光部１０２と受光部１０４とが測定対象空間Ｓ１を挟んで対向配置される装置形態であってもよい。
　また、図５に示すように、発光部１０２が発光する光（測定光１０１）で測定対象空間Ｓ１を走査する走査機構１１５を備えるものとしもよい。走査機構１１５は、出射及び受光する測定光１０１を反射するミラー１１５ａとこれを回転駆動する駆動部１１５ｂとを有する。ミラー１１５ａとしては、板状のものや断面多角形状で３面以上の反射面を有した多面鏡（ポリゴンミラー）などが一又は複数適用される。駆動部１１５ｂは、ミラー１１５ａを回転させるアクチュエーター（モーター）と、その駆動回路を有し、制御部１０３からの制御信号に基づきミラー１１５ａを回転させる。
　走査機構１１５により、１次元的、２次元的な濃度厚み積の分布を測定することができる。 In addition, when data based on the reference 106 is not used for the calculation, an element for obtaining this is not necessary. Further, the light emitting unit 102 is not limited to the device form that receives the reflected light from the reflector R1 as shown in FIG. It may be an apparatus in which the light receiving unit 104 is disposed so as to face the measurement target space S1.
In addition, as illustrated in FIG. 5, a scanning mechanism 115 that scans the measurement target space S <b> 1 with light emitted from the light emitting unit 102 (measurement light 101) may be provided. The scanning mechanism 115 includes a mirror 115a that reflects the measurement light 101 that is emitted and received, and a drive unit 115b that rotationally drives the mirror 115a. As the mirror 115a, one or a plurality of polygonal mirrors (polygon mirrors) having a plate shape, a polygonal cross section, and three or more reflecting surfaces are applied. The drive unit 115 b includes an actuator (motor) that rotates the mirror 115 a and a drive circuit thereof, and rotates the mirror 115 a based on a control signal from the control unit 103.
The scanning mechanism 115 can measure a one-dimensional and two-dimensional distribution of density thickness products.
　次に、演算部１０５が行う測定エラー判定につき説明する。
　受光信号時系列データを表すグラフ形状は、光源の波長変化（図２）と、測定対象ガスの光吸収波長特性によって決まるので、図８Ａに示すようなフラットから図８Ｂに示すような発光波長が吸収波長を通過するときに落ち込む形状が想定される。図８Ａはガスによる光吸収が無く正常の場合、図８Ｂはガスによる光吸収が有り正常の場合である。
　ガスの光吸収による負のピークａ１における受光強度は、ガスの濃度厚み積によって様々に変わり得る。
　しかし、時間軸上で吸収線位置ａ１以外の位置（例えば図８Ｃのａ４）で変化量は、ガスの有無、濃度厚み積によっては大きく変化しない。
　このようなガスの有無、濃度厚み積によっては大きく変化しない時間軸上の位置（例えば図８Ｃのａ４）で、大きく波形の乱れがあれば、測定光の出射先で測定対象ガスＧ１以外の環境要因等による波長の乱れである可能性が高いので、測定対象ガスＧ１の測定結果も信頼性が低い。
　したがって、演算部１０５は、時間軸上で吸収線位置ａ１以外の位置（例えば図８Ｃのａ４）の受光信号に基づき、その変化量が規定値を上回る場合、測定エラーと判定とする。 Next, measurement error determination performed by the calculation unit 105 will be described.
Since the graph shape representing the light reception signal time-series data is determined by the wavelength change of the light source (FIG. 2) and the light absorption wavelength characteristic of the measurement target gas, the emission wavelength as shown in FIG. 8B is changed from the flat as shown in FIG. 8A. A shape that falls when passing through the absorption wavelength is assumed. FIG. 8A shows a normal case without light absorption by gas, and FIG. 8B shows a normal case with light absorption by gas.
The received light intensity at the negative peak a1 due to light absorption of the gas can vary depending on the gas concentration thickness product.
However, the amount of change at a position other than the absorption line position a1 on the time axis (for example, a4 in FIG. 8C) does not change greatly depending on the presence or absence of gas and the concentration thickness product.
If there is a significant waveform disturbance at a position on the time axis (for example, a4 in FIG. 8C) that does not vary greatly depending on the presence / absence of the gas and the concentration / thickness product, the environment other than the measurement target gas G1 at the measurement light emission destination Since there is a high possibility of wavelength disturbance due to factors or the like, the measurement result of the measurement target gas G1 is also unreliable.
Therefore, based on the light reception signal at a position other than the absorption line position a1 (for example, a4 in FIG. 8C) on the time axis, the calculation unit 105 determines that the measurement error has occurred when the amount of change exceeds a specified value.
　次に、演算部１０５が行う距離の測定について説明する。
　距離測定原理は、ＴＯＦ法(Time Of Flight:飛行時間測定法)による。図９に模式的に示すように出射した光が反射物Ｒ１で反射し、 戻ってくるまでの時間τに基づき、ガス測定装置１００と反射物Ｒ１との間の距離Ｌ（発光部１０２から受光部１０４までの光路距離だと２Ｌ）を次式により測定する。
　Ｌ＝（光速）×（τ／２）
　以上のように、演算部１０５は、発光部１０２の発光タイミングと受光部１０４の受光タイミングの時差τに基づき、発光部１０２から受光部１０４までの光路距離を測定する。なお、図７に示すような発光部１０２と受光部１０４とが測定対象空間Ｓ１を挟んで対向配置される装置形態の場合は、上記式で２Ｌが空間Ｓ１を横断する距離に相当する。以上のようにして都度測定した距離又は既知の距離により基づき測定対象ガスＧ１の単位長さあたりの「濃度厚み積」、すなわち、濃度（平均濃度）が算出可能である。したがって、測定対象の空間Ｓ１における測定光の光路長が既知又は都度測定される場合は、「濃度厚み積」を単位長さあたりの「濃度厚み積」、すなわち、濃度（平均濃度）への換算値で算出してもよい。
　２ｆ方式でも原理的には可能だが、吸収線近傍で波長を変調させる必要があるため、振幅が非常に小さく、距離測定が難しくなる。
　一方、本発明によればパルス発光が可能なため、２ｆ検波方式と異なり、回路にクロック機能を持たせれば、１回の出射で距離を測定することができ、回路構成も簡易に距離測定が実現できる。 Next, distance measurement performed by the calculation unit 105 will be described.
The principle of distance measurement is based on the TOF method (Time Of Flight). As schematically shown in FIG. 9, the distance L between the gas measuring device 100 and the reflector R1 (received from the light emitting unit 102) is received based on the time τ until the emitted light is reflected by the reflector R1 and returns. 2L) for the optical path distance to the unit 104 is measured by the following equation.
L = (speed of light) × (τ / 2)
As described above, the calculation unit 105 measures the optical path distance from the light emitting unit 102 to the light receiving unit 104 based on the time difference τ between the light emission timing of the light emitting unit 102 and the light reception timing of the light receiving unit 104. In the case of an apparatus configuration in which the light emitting unit 102 and the light receiving unit 104 are opposed to each other with the measurement target space S1 interposed therebetween as shown in FIG. 7, 2L corresponds to the distance across the space S1 in the above formula. As described above, the “concentration thickness product” per unit length of the measurement target gas G1, that is, the concentration (average concentration) can be calculated based on the distance measured each time or the known distance. Therefore, when the optical path length of the measurement light in the measurement target space S1 is known or measured each time, the “concentration thickness product” is converted into the “concentration thickness product” per unit length, that is, the concentration (average concentration). You may calculate by a value.
Although it is theoretically possible even with the 2f method, the wavelength needs to be modulated in the vicinity of the absorption line, so that the amplitude is very small and distance measurement becomes difficult.
On the other hand, since pulse emission is possible according to the present invention, unlike the 2f detection method, if the circuit has a clock function, the distance can be measured by one emission, and the circuit configuration can be easily measured. realizable.
　以上の実施形態のガス測定装置によれば、発光部１０２に、落差のある２つの値の間で急峻に変化する電流を入力することで、ＤＦＢ－ＬＤの応答特性を利用して、発光部１０２が発光する光の波長に測定対象ガスＧ１の吸収波長及び非吸収波長に亘る変化を与えるので、比較的簡単な構成で発光及び受光検出、濃度厚み積の算出が可能であり、矩形波電流を一定にすることで発光の出力を一定に保つことができ、これにより発光の出力を一定に保った状態で吸収波長及び非吸収波長に亘り波長を変えて出力することができる。
　装置構成も２ｆ検波方式と同等以上に簡易あり、さらに光路距離の測定も可能である。
　レーザー光源の駆動制御のみで吸収波長及び非吸収波長が発振可能あり、検出器も一つで測定ができるため、非常に簡易な構成で、ガスの濃度厚み積の演算が実現できる。
　また、パルス発光の方がＣＷ発光に比べ、アイセーフティー状態を保ちながらハイパワーで出力が可能となるため、測定可能距離やＳＮ向上に有利に働く。
　図１に示すように所定周期のハルス波をＤＦＢ－ＬＤに入力することで、図３Ｂに示すように周期性の受光信号時系列データが得られる。一つの矩形部ａを対象に演算するにとどまらず、連続する複数の矩形部ａを対象に演算し、それらの演算結果に基づき測定結果を算出することで、Ｓ／Ｎを改善することがきる。その際、上述したエラー判定された矩形部ａを演算対象から除外することで、さらにＳ／Ｎを改善することがきる。 According to the gas measuring device of the above embodiment, by inputting the current that changes sharply between two values having a drop to the light emitting unit 102, the light emitting unit can be used by utilizing the response characteristics of the DFB-LD. Since the change over the absorption wavelength and non-absorption wavelength of the measurement target gas G1 is given to the wavelength of the light emitted by the light 102, it is possible to detect light emission and light reception and to calculate the concentration thickness product with a relatively simple configuration. The light emission output can be kept constant by keeping the light emission constant, and the light output can be changed over the absorption wavelength and the non-absorption wavelength while the light emission output is kept constant.
The apparatus configuration is as simple as or better than the 2f detection method, and the optical path distance can be measured.
The absorption wavelength and non-absorption wavelength can be oscillated only by driving control of the laser light source, and the measurement can be performed with one detector. Therefore, the calculation of the gas concentration / thickness product can be realized with a very simple configuration.
In addition, pulsed light emission is advantageous in improving measurable distance and SN because it can output with high power while maintaining eye safety state compared to CW light emission.
As shown in FIG. 1, by inputting a Hals wave having a predetermined period to the DFB-LD, periodic light reception signal time-series data is obtained as shown in FIG. 3B. S / N can be improved by calculating not only for one rectangular part a but also for a plurality of continuous rectangular parts a and calculating a measurement result based on the calculation result. . At this time, the S / N can be further improved by excluding the rectangular portion a determined as an error from the calculation target.
　本発明は、ガス測定及びガス測定装置に利用することができる。 The present invention can be used for gas measurement and gas measurement devices.
１００ ガス測定装置
１０１ 測定光
１０２ 発光部
１０３ 制御部
１０４ 受光部
１０５ 演算部
１０６ リファレンス
１０７ リファレンス受光部
１０９ ビームスプリッター
１１０ 増幅器
１１１ 増幅器
１１２ ＡＤ変換器
１１３ 電流制御部
１１４ 温度制御部
１２０ 投光ユニット
１２１ 受光ユニット
Ｇ１ 測定対象ガス
Ｒ１ 反射物
Ｓ１ 測定対象空間
ｔ１ 吸収線受光期間
ｔ２ 非吸収線受光期間
ｔ３ 吸収線受光期間
ｔ４ 非吸収線受光期間
λ１ 吸収波長
λ２ 非吸収波長 DESCRIPTION OF SYMBOLS 100 Gas measuring device 101 Measuring light 102 Light emission part 103 Control part 104 Light reception part 105 Calculation part 106 Reference 107 Reference light reception part 109 Beam splitter 110 Amplifier 111 Amplifier 112 AD converter 113 Current control part 114 Temperature control part 120 Light projection unit 121 Light reception Unit G1 Measurement object gas R1 Reflector S1 Measurement object space t1 Absorption line light reception period t2 Non-absorption line light reception period t3 Absorption line light reception period t4 Non-absorption line light reception period λ1 Absorption wavelength λ2 Non-absorption wavelength

Claims (15)

  1. 測定対象ガスを検出するための光を発光する発光部と、
    前記発光部の発光を制御する制御部と、
    前記発光部が発光し空間を経た光を受光する受光部と、
    前記受光部が受光した信号を処理する演算部と、を備えて前記空間における測定対象ガスの濃度厚み積を算出するガス測定装置であって、
    前記制御部は、前記発光部に急峻に変化する電流を入力することで、前記発光部が発光する光の波長に前記測定対象ガスの吸収波長及び非吸収波長に亘る変化を与え、
    前記演算部は、前記受光部が受光した前記吸収波長の光の受光信号及び前記非吸収波長の光の受光信号に基づき、前記測定対象ガスの濃度厚み積を算出するガス測定装置。     A light emitting unit that emits light for detecting the measurement target gas;
    A control unit for controlling light emission of the light emitting unit;
    A light receiving portion for receiving light emitted from the light emitting portion and passing through the space;
    A gas measurement device that calculates a concentration / thickness product of a measurement target gas in the space, and a calculation unit that processes a signal received by the light receiving unit,
    The control unit gives a change over the absorption wavelength and non-absorption wavelength of the measurement target gas to the wavelength of light emitted by the light emitting unit by inputting a current that changes sharply to the light emitting unit,
    The said calculating part is a gas measuring apparatus which calculates the concentration thickness product of the said measuring object gas based on the light reception signal of the light of the said absorption wavelength which the said light-receiving part received, and the light reception signal of the light of the said non-absorption wavelength.
  2. 前記演算部は、前記受光部が受光した前記吸収波長の光の受光信号と、前記非吸収波長の光の受光信号との差分に基づき測定対象ガスの濃度厚み積を算出する請求項１に記載のガス測定装置。 The said calculating part calculates the concentration thickness product of measurement object gas based on the difference of the light reception signal of the light of the said absorption wavelength which the said light-receiving part received, and the light reception signal of the light of the said non-absorption wavelength. Gas measuring device.
  3. 前記演算部は、前記受光部が受光した前記吸収波長及び前記非吸収波長に亘る受光信号時系列データを得て、当該受光信号時系列データに基づき、前記測定対象ガスの濃度厚み積を算出する請求項１に記載のガス測定装置。 The calculation unit obtains light reception signal time-series data over the absorption wavelength and the non-absorption wavelength received by the light-receiving unit, and calculates a concentration-thickness product of the measurement target gas based on the light reception signal time-series data. The gas measuring device according to claim 1.
  4. 前記演算部は、受光信号時系列データを、前記吸収波長の光を受光する吸収線受光期間で積分し当該積分値に基づき、前記測定対象ガスの濃度厚み積を算出する請求項３に記載のガス測定装置。 The said calculating part integrates the light reception signal time series data in the absorption line light reception period which receives the light of the said absorption wavelength, and calculates the concentration thickness product of the said measuring object gas based on the said integrated value. Gas measuring device.
  5. 前記演算部は、前記非吸収波長の光を受光する非吸収線受光期間で積分し当該積分値と、前記吸収線受光期間の積分値とに基づき、前記測定対象ガスの濃度厚み積を算出する請求項４に記載のガス測定装置。 The calculation unit integrates in a non-absorption line light receiving period for receiving light of the non-absorption wavelength, and calculates a concentration-thickness product of the measurement target gas based on the integration value and the integration value of the absorption line light reception period. The gas measuring device according to claim 4.
  6. 前記演算部は、前記非吸収波長の光の受光信号に基づき、測定エラーを判定する請求項１から請求項４のうちいずれか一に記載のガス測定装置。 The gas measurement device according to any one of claims 1 to 4, wherein the calculation unit determines a measurement error based on a light reception signal of the light having the non-absorption wavelength.
  7. 前記測定対象ガスの光吸収波長を示すリファレンスと、前記発光部が発光し前記リファレンスを経た光を受光するリファレンス受光部と、を備え、
    前記制御部は、前記リファレンス受光部の受光信号のフィードバックを得て、前記発光部に矩形波電流を入力することで、前記発光部が発光する光の波長に前記測定対象ガスの吸収波長及び非吸収波長に亘る変化を与える請求項１に記載のガス測定装置。     A reference indicating a light absorption wavelength of the measurement target gas, and a reference light receiving unit configured to receive the light emitted from the light emitting unit and passed through the reference,
    The control unit obtains feedback of the light receiving signal of the reference light receiving unit and inputs a rectangular wave current to the light emitting unit, so that the absorption wavelength of the measurement target gas and the non-wavelength of light emitted from the light emitting unit are increased. The gas measuring device according to claim 1 which gives change over absorption wavelength.
  8. 前記演算部は、前記受光部が受光した前記吸収波長の光の受光信号と、前記リファレンス受光部が受光した前記吸収波長の光の受光信号とに基づき測定対象ガスの濃度厚み積を算出する請求項７に記載のガス測定装置。 The calculation unit calculates a concentration-thickness product of the measurement target gas based on a light reception signal of the light having the absorption wavelength received by the light reception unit and a light reception signal of the light of the absorption wavelength received by the reference light reception unit. Item 8. The gas measuring device according to Item 7.
  9. 前記演算部は、前記受光部が受光した前記吸収波長及び前記非吸収波長に亘る受光信号時系列データ、及び前記リファレンス受光部が受光した前記吸収波長及び前記非吸収波長に亘るリファレンス受光信号時系列データを得て、当該受光信号時系列データと当該リファレンス受光信号時系列データとに基づき、前記測定対象ガスの濃度厚み積を算出する請求項７に記載のガス測定装置。 The calculation unit includes: the received light signal time series data over the absorption wavelength and the non-absorption wavelength received by the light receiving unit; and the reference received light signal time series over the absorption wavelength and the non-absorption wavelength received by the reference light receiving unit. 8. The gas measuring device according to claim 7, wherein data is obtained, and a concentration-thickness product of the measurement target gas is calculated based on the received light signal time series data and the reference received light signal time series data.
  10. 前記制御部は、前記発光部の温度を一定に制御する請求項１から請求項９のうちいずれか一に記載のガス測定装置。 The gas measuring device according to claim 1, wherein the control unit controls the temperature of the light emitting unit to be constant.
  11. 前記演算部は、前記制御部による前記矩形波電流の入力タイミング信号との同期と、前記矩形波電流の入力に伴う前記発光部が発光する光の波長の時間変化特性データの参照とが可能にされた請求項１から請求項１０のうちいずれか一に記載のガス測定装置。 The arithmetic unit can synchronize with the input timing signal of the rectangular wave current by the control unit, and refer to the time variation characteristic data of the wavelength of light emitted by the light emitting unit when the rectangular wave current is input. The gas measuring device according to any one of claims 1 to 10, wherein
  12. 前記発光部の発光素子として分布帰還型レーザダイオード（ＤＦＢ－ＬＤ）を備える請求項１から請求項１１のうちいずれか一に記載のガス測定装置。 The gas measuring device according to any one of claims 1 to 11, further comprising a distributed feedback laser diode (DFB-LD) as a light emitting element of the light emitting unit.
  13. 前記演算部は、前記発光部の発光タイミングと前記受光部の受光タイミングの時差に基づき、前記発光部から前記受光部までの光路距離を測定する請求項１から請求項１２のうちいずれか一に記載のガス測定装置。 The said calculating part measures the optical path distance from the said light emission part to the said light-receiving part based on the time difference of the light emission timing of the said light emission part, and the light reception timing of the said light-receiving part. The gas measuring device as described.
  14. 前記発光部が発光する光で前記空間を走査する走査機構を備える請求項１から請求項１３のうちいずれか一に記載のガス測定装置。 The gas measuring device according to claim 1, further comprising a scanning mechanism that scans the space with light emitted from the light emitting unit.
  15. 前記発光部と、前記受光部とが前記空間を挟んで対向配置される請求項１から請求項１３のうちいずれか一に記載のガス測定装置。 The gas measuring device according to any one of claims 1 to 13, wherein the light emitting unit and the light receiving unit are disposed to face each other with the space interposed therebetween.
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