Optical analysis device

Abstract

[Problem] To provide an optical analysis device capable of performing measurement at a shorter period of time with a higher accuracy. [Solution] An optical analysis device 1 comprises: a measurement cell 4 incorporated in a gas supply line; a semiconductor light source 2 disposed apart from the measurement cell 4; a distributor 7 that splits light emitted from the semiconductor light source 2 into transmission light 5 with which a measurement target substance in the measurement cell 4 is to be irradiated, and incoming light 6 that does not transmit through the measurement cell 4; a transmitted light detector 8 that detects transmitted light; an incoming light detector 9 that detects the incoming light; a temperature measurement element 10 that measures the state temperature of the semiconductor light source 2; a drive unit 15 that drives and turns on the semiconductor light source 2; and a control unit 17. The optical analysis device 1 stores a characteristic coefficient of the semiconductor light source in a memory 14 in advance, and, by means of a calculation unit 16, calculates the absorption coefficient of the measurement target substance at the time of measurement by using the temperature of the semiconductor light source 2 detected by the temperature measuring element 1 and calculates the concentration of the measurement target substance by absorptiometry.

Description

optical analyzer Cross Reference

[0001] This application claims priority based on Japanese Patent Application No. 2023-043392 filed in Japan on March 17, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to an optical analyzer that can accurately measure the concentration of a substance to be measured in a measurement cell by absorptiometry using a semiconductor light source. Specifically, the optical analyzer improves measurement accuracy by flowing the substance to be measured into a measurement cell, measuring the amount of absorption of the emitted light irradiated into the measurement cell, calculating the absorbance, and calculating an appropriate absorption coefficient corresponding to the absorbance from the state temperature of the semiconductor light source.

[0003] Conventionally, in this type of optical analyzer, the concentration is determined by irradiating the substance to be measured with monochromatic light whose absorption coefficient is compatible with the substance to be measured (see Patent Document 1).

[0004] International Publication No. 2020 / 158506

[0005] However, in measurements using semiconductor light sources, due to the nature of semiconductor light sources (unlike thermal radiation light sources), even the same type of light source has a wide emission wavelength range, and the emission wavelength changes due to self-heating and the influence of ambient temperature, so to improve measurement accuracy, it is necessary to calculate an appropriate absorption coefficient that corresponds to this wavelength change. Here, the appropriate absorption coefficient is the absorption coefficient when a certain compound shows maximum absorption at a single wavelength, and is obtained under standard measurement conditions.

[0006] Therefore, as a means of suppressing changes in the emission wavelength, it is common to provide a temperature control mechanism that uses a heating element or the like to maintain a constant temperature in the semiconductor light source. However, this mechanism is not desirable for an optical analyzer due to its requirements for miniaturization, structural simplicity, power consumption, and high structural costs. Furthermore, a temperature control mechanism does not have the effect of suppressing the wide emission wavelength range of semiconductor light sources.

[0007] In the case of in-line optical analyzers using semiconductor light sources that are directly connected to the main line during the manufacturing process, calibration is generally performed by removing the device from the piping and comparing concentrations at the manufacturer, which increases the time required for calibration.

[0008] Furthermore, semiconductor light sources have large variations in the emission wavelength range and temperature characteristics of individual devices, and to improve measurement accuracy, the light source must be paired with the optical analyzer and calibrated for concentration. However, it is difficult to calibrate the concentration of semiconductor light sources at the manufacturing site, and replacing the light source is also considered difficult. Therefore, the variations in the emission wavelength range and temperature characteristics that result from using semiconductor light sources have a negative impact on measurement accuracy.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an optical analysis device that can perform measurements with higher accuracy in a shorter time.

[0010] (1) To achieve the above object, one embodiment of an optical analysis device includes a measurement cell having a flow path through which a substance to be measured flows, a semiconductor light source that emits light at a wavelength that matches the absorption coefficient of the substance to be measured, a transmission window through which the light from the semiconductor light source passes, a transmitted light detector that detects the transmitted light in the measurement cell as the light from the semiconductor light source passes through the transmission window, an incident light detector that detects incident light that does not pass through the measurement cell, a distributor that branches the transmitted light and the incident light, a temperature measuring element that measures the state temperature of the semiconductor light source, a temperature sensor that measures the temperature of the substance to be measured, a pressure sensor that measures the pressure of the substance to be measured, and a drive unit that turns on the semiconductor light source.The characteristic coefficient of the semiconductor light source is stored in advance in a memory, and the absorption coefficient of the substance to be measured at the time of measurement is calculated in a calculation unit using the temperature detected by the temperature measuring element of the semiconductor light source, and the concentration of the substance to be measured is calculated by absorptiometry. (2) Another embodiment of an optical analysis device for achieving the above object includes a measurement cell having a flow path through which a substance to be measured flows, a semiconductor light source that emits light at a wavelength compatible with the absorption coefficient of the substance to be measured, a transmission window through which the light from the semiconductor light source passes, a transmitted light detector that detects the transmitted light in the measurement cell when the light from the semiconductor light source passes through the transmission window, an incident light detector that detects the incident light that does not pass through the measurement cell, a distributor that splits the transmitted light into the incident light, a temperature sensor that measures the temperature of the substance to be measured, a pressure sensor that measures the pressure of the substance to be measured, and a drive unit that turns on the semiconductor light source.The characteristic coefficient of the semiconductor light source is stored in memory in advance, and the calculation unit calculates the absorption coefficient of the substance to be measured during measurement using the detected temperature of the semiconductor light source, and calculates the concentration of the substance to be measured by absorptiometry.(3) In another embodiment of the optical analysis device, the distributor used to split the light from the semiconductor light source is preferably a beam splitter or a diffraction grating.(4) In another embodiment of the optical analysis device, the transmission window is preferably made of sapphire glass or quartz glass. (5) In another embodiment of the optical analysis device, the temperature measuring element of the semiconductor light source may preferably be a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature measuring element, or an infrared sensor, and may be configured to detect the state temperature of the mounting pad of the semiconductor light source.(6) In another embodiment of the optical analysis device, the temperature measuring element of the semiconductor light source may preferably be disposed on a substrate on which the semiconductor light source is mounted and may detect the state temperature. (7) In another embodiment of the optical analysis device, the temperature measuring element of the semiconductor light source may preferably be any of a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature measuring element, and an infrared sensor, disposed adjacent to the mounting pad of the semiconductor light source and contacting the pad via heat transfer by radiant heat or via a substance with high thermal conductivity to detect the state temperature. (8) In another embodiment of the optical analysis device, the temperature measuring element may preferably be any of a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature measuring element, and an infrared sensor, disposed adjacent to the substrate on which the semiconductor light source is mounted and contacting the pad via heat transfer by radiant heat or via a substance with high thermal conductivity to detect the state temperature. (9) In an optical analysis device according to another embodiment, a memory stores: a first characteristic coefficient of the semiconductor light source, which is an intrinsic peak wavelength when the semiconductor light source is measured at a reference temperature; a second characteristic coefficient of the semiconductor light source, which is an absorption sensitivity calibration ratio which is a relative ratio of an absorption coefficient calculated from the adapted peak wavelength and the intrinsic peak wavelength of the substance to be measured; a third characteristic coefficient of the semiconductor light source, which is a standard sensitivity calibration ratio which is a ratio of an absorption coefficient of the intrinsic peak wavelength calculated using a relationship between a standard peak wavelength at the reference temperature and the absorption coefficient of the substance to be measured and the absorption sensitivity calibration ratio; and a fourth characteristic coefficient of the semiconductor light source, which is a temperature coefficient of the standard peak wavelength at the reference temperature of the semiconductor light source and the absorption coefficient of the substance to be measured. a peak wavelength temperature coefficient ratio which is a relative coefficient between the temperature coefficient at the standard peak wavelength of the semiconductor light source and the temperature coefficient at the intrinsic peak wavelength, which is a fifth characteristic coefficient of the semiconductor light source; an appropriate absorption temperature coefficient which is a temperature coefficient ratio calculated from the relationship between the absorption temperature coefficient ratio at the adapted absorption coefficient which is the authorized absorption coefficient at which the substance to be measured absorbs most light and the peak wavelength temperature coefficient ratio, which is a sixth characteristic coefficient of the semiconductor light source; and an appropriate absorption sensitivity coefficient which is an absorption sensitivity coefficient between the absorption coefficient of the substance to be measured at the intrinsic peak wavelength at the reference temperature and the adapted absorption coefficient, which is a seventh characteristic coefficient of the semiconductor light source.(10) In another embodiment of the optical analysis device, the calculation unit preferably calculates an appropriate absorption coefficient of the substance to be measured according to the emission wavelength during measurement using a temperature measuring element that measures the state temperature of the semiconductor light source and a characteristic coefficient of the semiconductor light source. (11) In another embodiment of the optical analysis device, the current, voltage, or frequency of the driving power supply for the semiconductor light source may be varied to arbitrarily change the state temperature of the semiconductor light source and control the emission wavelength, and zero-point calibration may be performed by calculating the degree of contamination of the transmission window based on the absorption coefficient of the substance to be measured according to the emission wavelength. (12) In another embodiment of the optical analysis device, the semiconductor light source is preferably detachable, and a different semiconductor light source may be attached.

[0011] According to the present invention, it is possible to provide an optical analysis device that can perform measurements with higher accuracy in a shorter time.

[0012] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments and is not to be construed as limiting the invention.

[0013] REFERENCE SIGNS LIST 1 Optical analysis device 2 Semiconductor light source 3 Semiconductor manufacturing device 4 Measurement cell 7 Distributor 8 Transmitted light detector 9 Incident light detector 10 Temperature measuring element 11 Temperature sensor 12 Pressure sensor 13 Light source mounting substrate 14, 34 Memory (storage element) 15 Driving unit (driving power supply) 16 Calculating unit 17 Control unit 20 Inlet 21 Outlet 22 Flow path 23 Transmission window 24 Main gas line 25 Gas supply device

[0014] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the embodiments described below do not limit the inventions according to the claims. Furthermore, not all of the elements and combinations thereof described in the embodiments are necessarily essential to the solution of the present invention.

[0015] In this embodiment, Fig. 1 is a diagram showing the overall configuration of a concentration detection system including an optical analysis device 1 used in an embodiment of the present invention. Fig. 2 is a diagram showing the configuration of the optical analysis device 1 used in an embodiment of the present invention. Fig. 3 is a diagram for explaining the effects of an example of the present invention.

[0016] The optical analysis device 1 is connected to a gas supply device 25 and a main gas line 24 of the semiconductor manufacturing device 3, and is arranged so that the substance to be measured (the substance flowing in the direction of the arrow in Figure 1) flows into the measurement cell 4 (see Figure 2) from an inlet 20 and an outlet 21 provided at both ends of the measurement cell 4, which constitutes the optical analysis device 1, so that the concentration can be measured in-line.

[0017] [Optical Analysis Apparatus] As shown in FIG. 1 , the optical analysis apparatus 1 according to this embodiment includes a measurement cell 4 incorporated in a gas supply line, a semiconductor light source 2 disposed at a distance from the measurement cell 4, a drive unit (light source drive circuit) 15, a transmission window 23 through which light emitted from the semiconductor light source 2 passes through the measurement cell, a distributor 7 that splits the light emitted from the semiconductor light source 2 into transmitted light 5 that irradiates the substance to be measured in the measurement cell 4 and incident light 6 that does not pass through the measurement cell 4, a transmitted light detector 8 that detects the transmitted light, an incident light detector 9 that detects the incident light, a temperature measuring element 10 that measures the state temperature of the semiconductor light source 2, a temperature sensor 11 that measures the temperature of the substance to be measured, a pressure sensor 12 that measures the pressure of the substance to be measured, a drive unit (drive power supply) 15 that drives and lights up the semiconductor light source 2, and a control unit 17.

[0018] The distributor 7 is a beam splitter or diffraction grating used to split the light from the semiconductor light source 2. For the transmission window 23, sapphire is preferably used, which has high transmittance and resistance to detection light used in concentration measurement, such as ultraviolet light, and is mechanically and chemically stable, but other stable materials, such as quartz glass, can also be used.

[0019] The temperature measuring element 10 is configured to detect the state temperature of the mounting pad of the semiconductor light source 2 using a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature detector, an infrared sensor, or the like. The temperature measuring element 10 may be configured to be disposed on a substrate on which the semiconductor light source 2 is mounted and detect the state temperature. Alternatively, the temperature measuring element 10 may be configured to be disposed adjacent to the mounting pad of the semiconductor light source 2 and detect the state temperature by heat transfer via radiant heat or by contact via a material with high thermal conductivity using a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature detector, an infrared sensor, or the like. Alternatively, the temperature measuring element 10 may be disposed adjacent to the substrate on which the semiconductor light source is mounted and detect the state temperature by heat transfer via radiant heat or by contact via a material with high thermal conductivity. Alternatively, the temperature measuring element 10 may be detected without the temperature measuring element 10 by detecting the potential difference (forward voltage) between the anode and cathode electrodes of a diode constituting the semiconductor light source 2 and detecting the state temperature of the mounting pad of the semiconductor light source 2 based on the detected potential difference. In this case, temperature information based on the potential difference between the anode electrode and the cathode electrode of the diode is stored in a memory (storage element) 14. In this case, the temperature measuring element is not required, and the configuration is simpler.

[0020] The control unit 17 includes a memory (storage element) 14 that stores the detection signals from the transmitted light detector 8 and the incident light detector 9, temperature information acquired by the temperature measuring element 10 (including temperature information based on the potential difference between the anode and cathode electrodes of the diode), and the characteristic coefficient of the semiconductor light source 2, and a calculation unit 16 that calculates absorbance using the detection signals from the transmitted light detector 8 and the incident light detector 9 and calculates the extinction coefficient of the substance being measured in the light emitted by the semiconductor light source 2 using the temperature detected by the temperature measuring element 10. The temperature sensor 11, pressure sensor 12, transmitted light detector 8, incident light detector 9, temperature measuring element 10, and drive unit 15 in the measurement cell 4 are electrically connected to the control unit 17, for example, by optical fiber and a sensor cable. In this embodiment, a memory 34 having the same function as the memory 14 that stores multiple characteristic coefficients (described later) is provided on the light source mounting substrate 13, but it goes without saying that the control unit 17 may be configured with only one of the memories.

[0021] The memory (storage element) 14 stores (memorizes) multiple characteristic coefficients of the semiconductor light source 2 used. More specifically, at least one of the intrinsic peak wavelength, absorbance sensitivity calibration ratio, standard sensitivity calibration ratio, absorbance temperature coefficient, peak wavelength temperature coefficient ratio, appropriate absorbance temperature coefficient, and appropriate absorbance sensitivity coefficient is stored. The memory (storage element) 14 also stores various mathematical formulas (arithmetic processing programs) used in the concentration calculation process described below. In order to correct for differences in the optical path length of the measurement cell 4, the optical analysis device 1 must perform concentration calibration during the manufacturing process and store the cell sensitivity coefficient for absorbance in the memory 14. The definitions of the intrinsic peak wavelength, absorbance sensitivity calibration ratio, standard sensitivity calibration ratio, absorbance temperature coefficient, peak wavelength temperature coefficient ratio, appropriate absorbance temperature coefficient, and appropriate absorbance sensitivity coefficient will be described later.

[0022] The driving unit 15 can arbitrarily change the state temperature of the semiconductor light source 2 by varying the current, voltage, and frequency of the driving power supply for the semiconductor light source. Therefore, the emission wavelength of the light emitted from the semiconductor light source 2 can be arbitrarily controlled, and the calculation unit 16 can perform zero-point calibration by calculating the degree of contamination of the transmission window 23 based on the absorption coefficient of the substance to be measured corresponding to the emission wavelength.

[0023] [Measurement Cell] The measurement cell 4 has an inlet 20 and outlet 21 for the measurement gas, and a flow path 22 extending in the longitudinal direction. Translucent transmission windows 23 are provided at both ends of the measurement cell 4 in the direction of transmitted light propagation. Sapphire, which has high transmittance and resistance to detection light used in concentration measurement, such as ultraviolet light, and is mechanically and chemically stable, is preferably used for the transmission window 23, but other stable materials, such as quartz glass, can also be used. Note that, in this specification, "light" refers not only to ultraviolet light but also to at least infrared light and visible light, and may include electromagnetic waves of any wavelength. Translucency means that the internal transmittance of the light irradiated onto the measurement cell 4 is sufficiently high to enable concentration measurement.

[0024] The pressure sensor 12 detects the pressure of the substance (gas) to be measured flowing in the measurement cell 4, and the temperature sensor 11 measures the temperature of the substance to be measured. The outputs of the pressure sensor 12 and the temperature sensor 11 are input to the calculation unit 16 of the control unit 17 via a sensor cable (not shown). A plurality of temperature sensors 11 may be provided. As the temperature sensor 11, a thermistor, a thermocouple, or the like may also be used in addition to a resistance temperature detector.

[0025] As the light receiving elements constituting the transmitted light detector 8 and the incident light detector 9, for example, a photodiode or a phototransistor is preferably used.

[0026] [Semiconductor Light Source] The semiconductor light source 2 includes a light-emitting element (here, an LED) that emits ultraviolet light of a predetermined wavelength and a light source mounting substrate 13. A predetermined current, voltage, and frequency are output from the driver 15, and the transmitted light detector 8 detects a detection signal, from which the light intensity corresponding to each wavelength component can be measured. The light-emitting element can also be a light-emitting element other than an LED, such as an LD (laser diode). The semiconductor light source 2 may be configured to be detachable. This facilitates maintenance, such as replacing a different semiconductor light source. Furthermore, instead of a single-wavelength light source, multiplexed light of multiple different wavelengths can be used as the light source. In this case, two or more light-emitting elements, which require a multiplexer or frequency analysis circuit, may be provided, or the incident light may be generated using only a selected one of the provided light-emitting elements. Furthermore, the light emitted by the light-emitting element is not limited to ultraviolet light, but may also be visible light or infrared light.

[0027] [Control Unit] The control unit 17 is configured, for example, by a processor (including an internal memory) provided on a circuit board, includes a computer program that executes predetermined calculations based on input signals, and can be realized by a combination of hardware and software. In the illustrated embodiment, the calculation unit 16 is configured as part of the control unit 17, but it goes without saying that a part (such as a CPU) or the whole of the calculation unit may be provided in a device (such as a drive device including a drive unit) other than the device that includes the control unit 17.

[0028] [Concentration Measurement Processing] The calculation unit 16 calculates the absorbance using the detection signals from the transmitted light detector 8 and the incident light detector 9, and calculates the appropriate absorption coefficient α of the substance to be measured in the light emitted by the semiconductor light source 2 using the temperature detected by the temperature measuring element 10. ２ Specifically, in a state where a plurality of characteristic coefficients (seven coefficients) of the semiconductor light source 2 are stored in advance in the memory 14, the calculation unit 16 calculates the absorbance A using the detection signals from the transmitted light detector 8 and the incident light detector 9. ２ and calculates the appropriate absorption coefficient α of the substance to be measured at the time of measurement, which corresponds to the detected temperature Ta detected by the temperature measuring element 10 of the semiconductor light source 2. ２ and the fitted extinction coefficient α １ Ratio α ｆ and calculate the concentration C by spectrophotometric analysis.

[0029] [Concentration Calculation Process] The calculation unit 16 calculates the intensity I of the incident light that does not pass through the measurement cell 4. ０ and the intensity I of the transmitted light passing through the substance to be measured in the measurement cell 4. １ Absorbance A at the matching absorption wavelength １ is calculated, and the concentration C of the substance to be measured is calculated according to the following formula (1) based on the Beer-Lambert law. １ is the adapted absorption coefficient of the substance to be measured, and L is the optical path length of the measurement cell 4. The adapted absorption wavelength is the wavelength at which the substance to be measured absorbs most effectively, and the adapted absorption coefficient α １ is a coefficient that represents the characteristic of the substance to be measured absorbing light best at this wavelength. Note that "suitable" means that it is necessary for the substance to be measured to be measurable when actually used, and the suitable extinction coefficient is, for example, an extinction coefficient derived using monochromatic light (assuming that the wavelength does not shift), and is the extinction coefficient necessary for the substance to be measured to be measurable. １ = -log １０ (I １ / I ０ ) = α １ LC...(1)

[0030] Fitted extinction coefficient α １ is determined by the substance to be measured and the suitable emission wavelength, so when a semiconductor light source 2 is used, the emission wavelength also changes according to the change in the state temperature, and therefore the absorbance A２ In this case, the calculation unit 16 calculates the absorption coefficient α ２ The concentration C is calculated according to the following formula (2). ２ is the intensity I of the transmitted light that has passed through the substance to be measured in the measurement cell 4 after the emission wavelength has changed. ２ The incident light intensity at this time is calculated according to the following formula (3). ０ The strength shall be equivalent to that of ２ = α ２ LC...(2) A ２ = -log １０ (I ２ / I ０ ) ... (3)

[0031] Appropriate absorption coefficient α ２ is calculated using the characteristic coefficient of the semiconductor light source 2 and the detected temperature (Ta) of the temperature measuring element 10 of the semiconductor light source 2 according to the following formulas (4) and (5): ２ In calculating the α ２ and the fitted extinction coefficient α, which forms the basis for calculating the concentration １ Ratio α ｆ is calculated from the characteristic coefficient of the specific semiconductor light source 2, and the calculated adapted absorption coefficient α １ and ratio α ｆ Based on this, the appropriate extinction coefficient α ２ is calculated. ｆAccording to this embodiment, the following seven characteristic coefficients (first to seventh characteristic coefficients) are used to calculate the characteristic coefficients. The following explanation assumes that the same semiconductor light source is used, and the absorbance sensitivity represents the magnitude of absorbance as the magnitude of absorption ability. <First Characteristic Coefficient> Intrinsic Peak Wavelength (default peak λ) This refers to the intrinsic peak wavelength when the semiconductor light source is measured at a reference temperature. Here, the reference temperature refers to a reference temperature set in advance within the room temperature range. The reference temperature will be used in the following explanation in the same sense as above. <Second Characteristic Coefficient> Absorption Sensitivity Calibration Ratio (default abs ratio) This refers to the relative ratio between the adapted peak wavelength of the substance to the absorption coefficient calculated from the intrinsic peak wavelength and the adapted peak wavelength of the substance to be measured using the absorption spectrum of the substance to be measured. Here, the adapted peak wavelength refers to the wavelength used to calculate the adapted absorption coefficient. <Third Characteristic Coefficient> Standard Sensitivity Calibration Ratio (abs standard ratio) This refers to the ratio between the absorption coefficient of the intrinsic peak wavelength and the absorption sensitivity calibration ratio, calculated using the relationship between the standard peak wavelength at the reference temperature (hereinafter referred to as "standard peak wavelength") and the absorption coefficient of the substance being measured. <Fourth Characteristic Coefficient> Absorption Temperature Coefficient (abs temp para) This refers to the relative coefficient between the temperature coefficient of the standard peak wavelength of the semiconductor light source and the absorption coefficient of the substance being measured, and the temperature coefficient of the absorption sensitivity calibration ratio. <Fifth Characteristic Coefficient> Peak Wavelength Temperature Coefficient Ratio (peakλtemp para) This refers to the relative coefficient between the temperature coefficient of the standard peak wavelength of the semiconductor light source and the temperature coefficient of the intrinsic peak wavelength. <Sixth characteristic coefficient> Appropriate absorbance temperature coefficient (abs temp span para) Temperature coefficient ratio calculated from the relationship between the absorbance temperature coefficient ratio (fourth characteristic coefficient) and the peak wavelength temperature coefficient ratio (fifth characteristic coefficient) in the adapted absorbance coefficient <Seventh characteristic coefficient> Appropriate absorbance sensitivity coefficient (conc span para) This refers to the absorbance sensitivity coefficient between the absorbance coefficient of the measured substance at the intrinsic peak wavelength at the reference temperature and the adapted absorbance coefficient.

[0032] α ２ = α １ / α ｆ...(4) where the fitted extinction coefficient α １ is calculated by the above formula (1). The authorized absorption coefficient that the measured substance absorbs most light is called the adapted absorption coefficient. The appropriate absorption coefficient α ２ Regarding the calculation of , when the temperature rises, the emission wavelength shifts to the long wavelength side, and when the measured substance is irradiated with light of that wavelength, the sensitivity (amount of energy) decreases. To compensate for this decrease, the appropriate extinction coefficient α ２ α, which will be described later ｆ and the fitted extinction coefficient α １ Calculate using the appropriate extinction coefficient α ２ is the corrected extinction coefficient, and this value is applied to the formula (2) to calculate the appropriate concentration C. ｆ The calculation method of α will be explained. ｆ = abs span ratio(Ta) × mes ratio(Ta) × conc ratio(Ta) × abs temp span ratio × default abs ratio × conc span para / abs standard ratio ... (5) where the ratio α ｆ is calculated by the above formula (5), but among the parameters, "abs span ratio(Ta)", "mes ratio(Ta)", "conc ratio(Ta)", and "abs temp span ratio" are calculated according to the following formulas (5-1) to (5-10).

[0033] Formulas (5-1) to (5-10) will be explained in order below. (I) abs span ratio(Ta): intrinsic absorption coefficient ratio at state temperature (variable value) abs span ratio(Ta)=((abs ratio(Ta)-1)×abs temp para / abs standard ratio+1)×abs standard ratio (5-1) where, (A) abs ratio(Ta)=abs ratio a(Ta)×(real peak λ(Ta))4 + absolute ratio b(Ta) × (real peak λ(Ta)) 3 + absolute ratio c(Ta) × (real peak λ(Ta)) 2 + absolute ratio d(Ta) × real peak λ(Ta) + absolute ratio e(Ta) ······(5 - 2) Here, each parameter in the formula (5 - 2) is calculated by the following formulas (5 - 2 - 1) to (5 - 2 - 5), (5 - 3). · absolute ratio a(Ta) = (ka1) × (Ta) 4 + (ka2) × (Ta) 3 + (ka3) × (Ta) 2 + (ka4) × (Ta) + (ka5) ······(5 - 2 - 1) · absolute ratio b(Ta) = (kb1) × (Ta) 4 + (kb2) × (Ta) 3 + (kb3) × (Ta) 2 + (kb4) × (Ta) + (kb5) ······(5 - 2 - 2) · absolute ratio c(Ta) = (kc1) × (Ta) 4 + (kc2) × (Ta) 3 + (kc3) × (Ta) 2 + (kc4) × (Ta) + (kc5) ······(5 - 2 - 3) · absolute ratio d(Ta) = (kd1) × (Ta) 4 + (kd2) × (Ta) 3 + (kd3) × (Ta) 2 + (kd4) × (Ta) + (kd5) ······(5 - 2 - 4) · absolute ratio e(Ta) = (ke1) × (Ta) 4 + (ke2) × (Ta) 3 + (ke3) × (Ta) 2 + (ke4) × (Ta) + (ke5) ······(5 - 2 - 5) Note that ka1 to ka5, kb1 to kb5, kc => 1 to kc5, kd1 to kd5, ke1 to ke5 are constants.

[0034] (B) real peakλ(Ta)={{(real peakλa(Ta)×(peakλ(Ta)) 2 + real peakλb(Ta) × peakλ(Ta) + real peakλc(Ta)) - 1} × peakλtemp para + 1} × default peakλ ... (5-3) Here, each parameter in the formula (5-3) is calculated using the following formulas (5-3-1) to (5-3-5) and (5-4). real peakλa(Ta) = (wa1) × (Ta) 2 +(wa2)×Ta+(wa3) ・・・・・・(5-3-1) ・real peakλb(Ta)=(wb1)×(Ta) 2 +(wb2)×Ta+(wb3) ・・・・・・(5-3-2) ・real peakλc(Ta)=(wc1)×(Ta) 2 +(wc2)×Ta+(wc3) .... (5-3-3) Note that wa1 to wa3, wb1 to wb3, and wc1 to wc3 are constants. (C) peakλ(Ta) = {(z1)×(Ta) 2 +(z2)×(Ta)+(z3)×(default peak λ) ... (5-4) where z1 to z3 are constants.

[0035] (II) mes ratio(Ta): intrinsic absorption coefficient ratio at reference temperature mes ratio(Ta) = mes ratio a(To) × (real peak λ(Ta)) 3 +mes ratio b(To)×(real peakλ(Ta)) 2+mes ratio c(To) × real peak λ(Ta) +mes ratio d(To) ................................... (5-5) Here, each parameter in the formula (5-5) is calculated using the following formulas (5-5-1) to (5-5-4). (A)mes ratio a(To) = (ma1) × (To) 3 +(ma2)×(To) 2 +(ma3)×(To)+(ma4) ・・・・・・(5-5-1) (B) mes ratio b(To)=(mb1)×(To) 3 +(mb2)×(To) 2 +(mb3)×(To)+(mb4) ・・・・・・(5-5-2) (C) mes ratio c(To)=(mc1)×(To) 3 +(mc2)×(To) 2 +(mc3)×(To)+(mc4) ・・・・・・(5-5-3) (D) mes ratio d(To)=(md1)× (To) 3 +(md2)×(To) 2 +(md3)×(To)+(md4) (5-5-4) Note that ma1 to ma4, mb1 to mb4, mc1 to mc4, and md1 to md4 are constants, and real peak λ(Ta) is calculated from formula (5-3).

[0036] (III) conc ratio(Ta): Conc ratio(Ta) = conc ratio a(To) × (real peak λ(Ta)) 3 +conc ratio b(To)×(real peakλ(Ta)) 2+ conc ratio c(To) × real peak λ(Ta) + conc ratio d(To) ... (5-6) Here, each parameter in formula (5-6) except for real peak λ(Ta) is calculated using the following formulas (5-6-1) to (5-6-4), and real peak λ(Ta) is calculated from formula (5-3). (A) conc ratio a(To) = (na1) × (To) 3 +(na2)×(To) 2 +(na3)×(To)+(na4) ・・・・・・(5-6-1) (B) conc ratio b(To)=(nb1)×(To) 3 +(nb2)×(To) 2 +(nb3)×(To)+(nb4) ・・・・・・(5-6-2) (C) conc ratio c(To)=(nc1)×(To) 3 +(nc2)×(To) 2 +(nc3)×(To)+(nc4) ・・・・・・(5-6-3) (D) conc ratio d(To)=(nd1)×(To) 3 +(nd2)×(To) 2 +(nd3)×(To)+(nd4) (5-6-4) Note that na1 to na4, nb1 to nb4, nc1 to nc4, and nd1 to nd4 are constants, and real peak λ(Ta) is calculated from formula (5-3).

[0037] (IV) abs temp span ratio: Ratio of the intrinsic absorption coefficient at the state temperature to the reference temperature abs temp span ratio (Ta)=((((abs ratio (To)-1)×abs temp para / abs standard ratio +1) / ((abs ratio (Ta)-1)×abs temp para / abs standard ratio+1))-1)×abs temp span para+1 ... (5-7) The abs ratio (Ta) is calculated from formula (5-2), and the abs ratio (To) is calculated from the following formula (5-8). (A) abs ratio(To)=abs ratio a(To)×(real peak λ(To)) 4 +abs ratio b(To)×(real peakλ(To)) 3 +abs ratio c(To)×(real peakλ(To)) 2 +abs ratio d(To)×real peak λ(To) +abs ratio e(To) (5-8) Here, each parameter in the formula (5-8) is calculated using the following formulas (5-8-1) to (5-8-5). (B) abs ratio a(To)=(ka1)×(To) 4 +(ka2)×(To) 3 +(ka3)×(To) 2 +(ka4)×(To)+(ka5) ・・・・・・(5-8-1) (C) abs ratio b(To)=(kb1)×(To) 4 +(kb2)×(To) 3 +(kb3)×(To) 2 +(kb4)×(To)+(kb5) ・・・・・・(5-8-2) (D) abs ratio c(To)=(kc1)×(To) 4 +(kc2)×(To) 3 +(kc3)×(To) 2+(kc4)×(To)+(kc5) ・・・・・・(5-8-3) (E) abs ratio d(To)=(kd1)×(To) 4 +(kd2)×(To) 3 +(kd3)×(To) 2 +(kd4)×(To)+(kd5) ・・・・・・(5-8-4) (F) abs ratio e(To)=(ke1)×(To) 4 +(ke2)×(To) 3 +(ke3)×(To) 2 +(ke4)×(To)+(ke5) ... (5-8-5) Note that ka1 to ka5, kb1 to kb5, kc1 to kc5, kd1 to kd5, and ke1 to ke5 are constants.

[0038] (IV-1) Here, real peak λ(To) is calculated by the following formula (5-9): (A) real peak λ(To)={{(real peak λa(To)×(peak λ(To)) 2 + real peakλb(To) × peakλ(To) + real peakλc(To)) - 1} × peakλtemp_para + 1} × default peakλ ... (5-9) Note that real peakλa(To), real peakλb(To), and real peakλc(To) in formula (5-9) are calculated from the following formulas (5-9-1) to (5-9-3), respectively. (a1) real peakλa(To) = (wa1) × (To) 2 +(wa2)×To+(wa3) ・・・・・・(5-9-1) (a2) real peakλb(To)=(wb1)×(To) 2 +(wb2)×To+(wb3) ・・・・・・(5-9-2) (a3) ​​real peakλc(To)=(wc1)×(To) 2+(wc2)×To+(wc3) ... (5-9-3) Note that wa1 to wa3, wb1 to wb3, and wc1 to wc3 are constants. Also, peak λ(To) in formula (5-9) is calculated using the following formula (5-10). (a4) peak λ(To) = {(z1) × (To) 2 +(z2)×(To)+(z3)×(default peakλ) ... (5-10) where z1 to z3 are constants.

[0039] As explained above, the concentration C is calculated by the formulas (1) to (5). In the above-described embodiment, the calculation unit 16 receives state temperature information from the temperature measuring element 10 in real time and performs calculations according to the formulas (1) to (5), but it is also possible to store the calculation results of the formulas (1) to (5) for a plurality of state temperatures in advance as a table in memory, so that the concentration can be calculated automatically when an actually detected state temperature is received.

[0040] When the concentration C is treated as the standard state concentration Co, the measured temperature Tc (°C) and state pressure Pa (kPa) of the substance to be measured are detected by the temperature sensor 11 and pressure sensor 12, respectively, and converted into a concentration based on the following formula (6): Co = C × {(273.15 + Tc) / 273.15} × {101.32 / (101.32 + Pa)} (6)

[0041] In this example, the calculation unit 16 calculates the adapted extinction coefficient α when the detected temperature (Ta) of the temperature measuring element 10 of the semiconductor light source 2 changes in four steps of 15° C., 25° C., 35° C., and 45° C. １ (ozone gas) ratio α ｆ is calculated by calculating the above-mentioned formula (5) using the characteristic coefficient of the semiconductor light source 2 and the detected temperature of the temperature measuring element 10 of the semiconductor light source 2, and the adapted absorption coefficient α1 at the state temperature during measurement and the calculated ratio α ｆ and are substituted into equation (4) to obtain the appropriate absorption coefficient α ２ The absorbance A ２, the optical path length L of the measurement cell 4 and the appropriate absorption coefficient α ２ Based on the above, the concentration C is calculated according to the formula (2).

[0042] 3A shows the characteristics showing the relationship between the concentration C calculated using a semiconductor light source based on the concentration calculation method described above and converted into an ozone gas concentration value, and the temperature (Ta) detected by the temperature measuring element 10. Also, FIG. 3B shows the characteristics showing the relationship between the concentration C calculated using a semiconductor light source and converted into an ozone gas concentration value under conditions where the first to seventh characteristic coefficients are not applied, and the temperature (Ta) detected by the temperature measuring element 10.

[0043] The characteristic graph (c) shows the incident light intensity I that does not pass through the measurement cell 4 using a mercury lamp as the light source and monochromatic light that matches the absorption coefficient of ozone gas, which is the substance to be measured. ０ and the intensity I of the transmitted light passing through the ozone gas in the measurement cell 4. １ Absorbance A １ and calculate the fitted extinction coefficient α, which is the basis for calculating the concentration based on the Beer-Lambert law. １ 10 is a characteristic graph in the case where the concentration C of the substance to be measured is calculated according to the formula (1).

[0044] (C) on the characteristic graph shows the absorbance A １ The absorbance A is calculated using equation (1) on the assumption that it does not change with the change in the light source temperature, and as the temperature detected by the temperature measuring element of the light source increases, the ozone gas concentration gradually increases. On the other hand, as shown in (A) of the characteristic graph, １ A changes depending on the change in light source temperature. ２ When the temperature is changed to 0.01 and the first to seventh characteristic coefficients are not applied, the ozone gas concentration gradually decreases as the temperature detected by the temperature measuring element of the light source increases, and the measurement accuracy deteriorates.

[0045] Therefore, the absorbance A １ A changes depending on the change in light source temperature. ２ When the first to seventh characteristic coefficients are applied, as shown in (A) of the characteristic graph, as the temperature detected by the temperature measuring element of the light source increases, there is almost no increase in the ozone gas concentration, which indicates that the measurement accuracy is high.

[0046] [Effects of this embodiment] Therefore, with the optical analyzer according to this embodiment, it is possible to improve the accuracy of concentration measurement without performing temperature control to maintain a constant state temperature of the semiconductor light source using a heating element, etc. Furthermore, in the past, in-line optical analyzers that are directly connected to the main line during the manufacturing process were unable to calibrate sensitivity for concentration comparison, so calibration was generally performed by removing the analyzer from the piping at the manufacturer. However, with this embodiment, measurements can be performed without removing the analyzer, allowing measurements to be performed in a shorter time.

[0047] In addition, when the temperature of the semiconductor light source rises during measurement, the emission wavelength shifts to the long wavelength side, and when the measured substance is irradiated with light of that wavelength, the sensitivity (amount of energy) drops. To compensate for this drop, the appropriate absorption coefficient α ２ The above α ｆ and the fitted extinction coefficient α １ The corrected appropriate extinction coefficient α ２ is applied to the above-mentioned formula (2) to calculate the appropriate concentration C, so that more accurate measurements can be performed.

[0048] Furthermore, in the above-described embodiment, more accurate measurements can be achieved by performing the following process. The photometric analyzer according to this embodiment is used to perform the following measurements on different substances to be measured (first substance to be measured and second substance to be measured). The concentration of the first substance to be measured is kept constant, and the state temperature of the semiconductor light source is arbitrarily changed by the driving power supply of the semiconductor light source (the emission wavelength changes and two emission wavelengths are identified), and the concentration (Cx) is calculated from two or more absorption coefficients (αx) and absorbances (Ax) corresponding to each emission wavelength. The appropriate absorption coefficient (α2) and absorbance (A2) of the substance to be measured at each concentration are calculated based on absorptiometry, and the first concentration Cx corresponding to each emission wavelength is calculated from each appropriate absorption coefficient (α2) and absorbance (A2). １The concentration of the second substance to be measured is kept constant, and the state temperature of the semiconductor light source is arbitrarily changed by the drive power supply of the semiconductor light source (the emission wavelength changes and two emission wavelengths are identified), and the concentration (Cx) is calculated from two or more absorption coefficients (αx) and absorbances (Ax) corresponding to each emission wavelength. The appropriate absorption coefficient (α2) and absorbance (A2) of the substance to be measured at each concentration are calculated based on the absorptiometric analysis method, and the second concentration C corresponding to each emission wavelength is calculated from each appropriate absorption coefficient (α2) and absorbance (A2). ２ As a result, different analyte concentrations C １ , C ２ The different analyte concentrations C １ , C ２ Measurement accuracy can be improved by calculating the degree of contamination from this and performing zero-point calibration. αx, Ax, Cx, α2, and A2 are as follows: αx: arbitrary absorption coefficient corresponding to the emission wavelength Ax: arbitrary absorbance corresponding to the emission wavelength Cx: concentration calculated from the arbitrary absorption coefficient and absorbance corresponding to the emission wavelength α2: appropriate absorption coefficient at that time A2: absorbance at the appropriate absorption coefficient at that time

[0049] [Applications in the field of measurement] By arbitrarily changing the emission wavelength using the driving power supply of the semiconductor light source, concentration errors can be determined in absorptiometric analysis by using the relationship between the absorption coefficient of the substance being measured and incompatible wavelengths.In fluorescence analysis, concentration errors can be determined by scanning the irradiation wavelength and using the reflected fluorescence intensity, and it can also be used for qualitative and quantitative analysis.

[0050] [Application in the Sterilization Field] In the field of sterilization and disinfection using ultraviolet light, it is known that the effect varies greatly depending on the wavelength range of the light. The emission wavelength can be controlled arbitrarily using the driving power supply of the semiconductor light source, and the state temperature of the semiconductor light source can be detected using a temperature measuring element (which detects the potential difference (forward voltage) between the anode and cathode electrodes of the diode that constitutes the semiconductor light source 2), thereby monitoring the emission wavelength and enabling appropriate wavelength control.

Claims

1. an incident light detector that detects incident light that does not pass through the measurement cell; a distributor that branches the light into transmitted light and incident light; a temperature measuring element that measures the state temperature of the semiconductor light source; and a drive unit that turns on the semiconductor light source, wherein a characteristic coefficient of the semiconductor light source is stored in advance in a memory, and an arithmetic unit calculates the absorption coefficient of the substance to be measured during measurement using the temperature detected by the temperature measuring element of the semiconductor light source, and the characteristic coefficient of the semiconductor light source is determined by an amount of change based on the temperature detected by the temperature measuring element, thereby calculating the concentration of the substance to be measured by absorptiometry.

2. an incident light detector that detects incident light that does not pass through the measurement cell; a distributor that branches the transmitted light into incident light; and a drive unit that turns on the semiconductor light source, wherein a characteristic coefficient of the semiconductor light source is stored in advance in a memory, and an arithmetic unit calculates the absorption coefficient of the substance to be measured during measurement using the characteristic coefficient of the semiconductor light source, which is determined by an amount of change based on the detected temperature of the semiconductor light source, to calculate the concentration of the substance to be measured by absorptiometry.

3. The distributor used to split the light from the semiconductor light source is a beam splitter or a diffraction grating.

3. The optical analysis device according to claim 1 or 2.

4. The transmission window is made of sapphire glass or quartz glass.

3. The optical analysis device according to claim 1 or 2.

5. the temperature measuring element of the semiconductor light source detects the state temperature of the mounting pad of the semiconductor light source using one of a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature measuring element, and an infrared sensor; 2. The optical analysis device according to claim 1.

6. a temperature measuring element of the semiconductor light source that is disposed on a substrate on which the semiconductor light source is mounted and detects the state temperature; 2. The optical analysis device according to claim 1.

7. The temperature measuring element of the semiconductor light source is a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature measuring element, or an infrared sensor, and is disposed adjacent to the mounting pad of the semiconductor light source and is in contact with the mounting pad via a material having high thermal conductivity or heat transfer by radiant heat, thereby detecting the state temperature.

2. The optical analysis device according to claim 1.

8. The temperature measuring element is configured to detect the state temperature by using any one of a resistance temperature detector, a thermistor, a thermocouple, a semiconductor temperature measuring element, and an infrared sensor, and is arranged adjacent to a substrate on which the semiconductor light source is mounted, and is in contact with the substrate via a material having high thermal conductivity or heat transfer by radiant heat.

2. The optical analysis device according to claim 1.

9. In the memory, a first characteristic coefficient of the semiconductor light source, which is a characteristic peak wavelength when the semiconductor light source is measured at a reference temperature; an absorption sensitivity calibration ratio, which is a second characteristic coefficient of the semiconductor light source and is a relative ratio between the adapted peak wavelength of the substance to be measured and the absorption coefficient calculated from the intrinsic peak wavelength; a standard sensitivity calibration ratio, which is a third characteristic coefficient of the semiconductor light source, and is the ratio between the absorption coefficient of an intrinsic peak wavelength calculated using the relationship between a standard peak wavelength at a reference temperature and the absorption coefficient of the substance to be measured and the absorption sensitivity calibration ratio; an absorption temperature coefficient, which is a fourth characteristic coefficient of the semiconductor light source, and is a relative coefficient between a standard peak wavelength at a reference temperature of the semiconductor light source and a temperature coefficient of the absorption coefficient of the substance to be measured; a fifth characteristic coefficient of the semiconductor light source, which is a peak wavelength temperature coefficient ratio, which is a relative coefficient between a temperature coefficient at the standard peak wavelength of the semiconductor light source and a temperature coefficient at the intrinsic peak wavelength; a sixth characteristic coefficient of the semiconductor light source, which is an appropriate extinction temperature coefficient, which is a temperature coefficient ratio calculated from the relationship between the extinction temperature coefficient ratio of an adapted extinction coefficient, which is an authorized extinction coefficient at which the substance to be measured absorbs light most, and the peak wavelength temperature coefficient ratio; a seventh characteristic coefficient of the semiconductor light source, which is an appropriate absorption sensitivity coefficient that is an absorption sensitivity coefficient between the absorption coefficient of the substance to be measured at the intrinsic peak wavelength at the reference temperature and the adapted absorption coefficient; At least one characteristic coefficient among 9. The optical analysis device according to claim 1, wherein the optical analysis device is a liquid crystal display.

10. the calculation unit calculates an absorption coefficient of the substance to be measured according to the emission wavelength at the time of measurement using the state temperature of the semiconductor light source and the characteristic coefficient of the semiconductor light source according to claim 9.

10. The optical analysis device according to claim 9.

11. By varying the power of the driving power supply of the semiconductor light source, the state temperature of the semiconductor light source is arbitrarily changed to control the emission wavelength, and different concentrations of the measured substance and the degree of contamination of the transmission window are calculated from the absorption coefficient to perform zero-point calibration.

3. The optical analysis device according to claim 1 or 2.

12. The semiconductor light source is detachable.

3. The optical analysis device according to claim 1 or 2.