JPH0933351A - Multiple wavelength type radiation temperature measuring method and multiple wavelength type radiation thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress temperature measurement error caused by a plurality of emissivity values and an arithmetic problem to improve the precision of measurement by preventing the function relation between wavelength power ratio and emissivity for determining the emissivity from the wavelength power ratio or radiant intensity of the heat radiant light from a body to be temperature-measured having a plurality of wavelength from being many-valued functional. SOLUTION: The heat radiant light from a body 1 to be temperature-measured is incident on spectral parts 5A, 5B. As the spectral part 5A, an optical filter for transmitting a light having a prescribed wavelength is used, it outputs a light having wavelength λ1, and this light is converged by a photoelectric converting part 7A to output a brightness temperature S1. The spectral part 5B outputs a light having a wavelength λ2 by a prescribed optical filter, and this light is converged by a photoelectric converting part 7B to output a brightness temperature S2. An emissivity calculating part 13A determines the emissivity ε1 from an EPR 1 outputted from an emissivity power ratio(EPR) calculating part 11A by use of a data table according to the straight line regressing a curve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calculation amount corresponding to two of the respective radiant intensities of the spectrum of thermal radiation from a temperature-measuring object, which wavelengths are different from each other. From the ratio of the powers, the emissivity of the temperature-measured body at at least one of the wavelengths is obtained, and at least:
From the emissivity and the radiant intensity of the wavelength corresponding to the emissivity, a multi-wavelength radiation temperature measuring method for obtaining the temperature of the temperature-measuring object, and a multi-wavelength radiation thermometer, in particular, It is possible to prevent the functional relationship between these for obtaining the emissivity from the exponentiation ratio from becoming a polyvalent function, and thereby, a temperature measurement error or calculation due to a plurality of values of the emissivity being obtained. The present invention relates to a multi-wavelength radiation temperature measuring method and a multi-wavelength radiation thermometer capable of suppressing the above problems and improving temperature measurement accuracy.

[0002]

2. Description of the Related Art Conventionally, the temperature of a temperature-measured body has been measured from the heat radiation light from the temperature-measured body based on Wien's law. For example, the radiation law of Vienna that the radiant energy of the thermal radiation changes according to the temperature of the temperature-measuring object, and the wavelength at which the radiant energy of the thermal radiation becomes maximum depending on the temperature of the temperature-measuring object is A radiation temperature measuring method and a radiation thermometer using the Wien's displacement law of changing are conventionally used.

In recent years, an emissivity-correcting type measurement is performed in accordance with the radiant energy of each of the spectra of the thermal radiation from the temperature-measured body, which has two or more wavelengths and a plurality of different wavelengths. Wen technology is known. For example, Japanese Patent Laid-Open No. 5-
In 126642, first of two wavelengths different from each other,
The ratio of the radiant energy of each spectrum of thermal radiation from the temperature-measured body to the power of each wavelength is obtained. or,
The emissivity of the object to be measured is obtained from the obtained power ratio and the measured radiant energy of each wavelength, and the temperature of the object to be measured is obtained from the emissivity and the measured radiant energy.

The principle of the conventional emissivity-correcting temperature measuring technique will be described below, centering on the temperature measuring technique disclosed in Japanese Patent Laid-Open No. 5-126642.

First, a plurality of different wavelengths are set to λi (i
= 1, 2, 3 ... N). Further, the radiant energy of each wavelength λi obtained by spectrally radiating the thermal radiation from the temperature-measured body is defined as Ei, and the brightness temperature of each wavelength λi obtained from the radiant energy Ei based on the above-mentioned Wien's radiation law is expressed as Si. And The radiant energy Ei and the brightness temperature Si are collectively referred to as radiant intensity hereinafter. Here, the emissivity of the temperature-measured body at each wavelength λi is εi, and the second Planck's constant is C2 (14388 μm · K).
Then, the radiant energy Ei and the temperature T of the object to be measured are
Based on Vienna's law, it can be expressed as

Ei = εi · exp {−C2 / (λi · T)} (1) 1 / T = 1 / Si + (λi / C2) ln (εi) (2)

Here, assuming that the number of wavelengths used in the following radiation temperature measurement is two, that is, the wavelengths λ1 and λ2 are used, the above equations (1) and (2) are expressed by the wavelengths λ1 and λ2. For the spectroscopy of, the following formula is obtained.

E1 = ε1 · exp {−C2 / (λ1 · T)} (1a) E2 = ε2 · exp {−C2 / (λ2 · T)} (1b) 1 / T = 1 / S1 + (λ1 / C2) ln (ε1) (2a) 1 / T = 1 / S2 + (λ2 / C2) ln (ε2) (2b)

If T is eliminated from the above equations (2a) and (2b), the following equation can be obtained.

[0010]

[Equation 1]

Incidentally, an arbitrary n wavelength λi (i is 1 to n)
For two of these wavelengths λi and λj (1
~ I ~ j ~ n or 1 ~ j ~ i ~ n), the above (3
The expression a) can be generalized as the following expression.

[0012]

[Equation 2]

Here, the ratio of the emissivity raised to the power is defined as the emissivity exponentiation ratio EPRi or EPR1 as in the following equation (4) or (4a). In addition,
The above-mentioned Japanese Unexamined Patent Publication No.
In 126642, the ratio of the radiant energy of each of the two wavelengths raised to the power of each wavelength is given by the following (5)
The power ratio X is represented by the equation or the equation (5a).
The ratio of the arithmetic quantities corresponding to the radiation intensities of the two wavelengths including EPRi, EPR1, and X raised to the respective powers of the respective wavelengths will be simply referred to as a power ratio hereinafter.

[0014]

(Equation 3)

Here, there is a fixed functional relationship between the emissivity exponentiation ratio EPR1 (or EPRi) and the emissivity ε1 (or εi). Therefore, such a relation is calculated,
Alternatively, it can be determined in advance by measuring the emissivity. The function thus obtained is F1 (or Fi)
Then, it can be expressed by the following equation.

[0016]

(Equation 4)

Therefore, if the emissivities ε1 and εi are obtained from the above equations (6a) and (6), the above-mentioned brightness temperatures S1 and S are obtained.
Based on 2 or Si, the temperature T of the temperature-measured body can be obtained by using the equations (2a) and (2) or the following equation.

T = (λj−λi) / {(λi · λj / C2) ln (εi / εj) + λj / Si−λi / λj} (7) T = (λ2-λ1) / {(λ1 · λ2 / C2) ln (ε1 / ε2) + λ2 / S1-λ1 / S2} (7a)

Here, FIG. 14 is a block diagram showing the structure of a conventional multi-wavelength radiation thermometer for measuring the surface temperature of a temperature-measuring object according to the above-described measurement principle.

This radiation thermometer measures the temperature using the spectrum of the two wavelengths λ1 and λ2 of the heat radiation light from the object to be measured 1. The multi-wavelength radiation thermometer includes spectroscopic units 5D and 5D.
E, photoelectric conversion units 7A and 7B, and EPR calculation unit 11A
The emissivity calculator 13C, the temperature calculator 15A, and the temperature data storage / output unit 17 are included.

First, the spectroscopic sections 5D and 5E are shown in FIG.
Is as shown in the spectroscopic section 5 of. That is, the spectroscopic units 5D and 5E include a condensing optical unit 81 for condensing the heat radiation light from the temperature-measured body 1 onto the temperature measuring element 85, and a wavelength λ1 or λ2 (Fig. In λi inside, i =
Optical filter 8 for obtaining the spectrum of 1 or i = 2)
And 2.

The photoelectric conversion units 7A and 7B are constructed as the photoelectric conversion unit 7 of FIG. That is, these photoelectric conversion units 7A and 7B are radiant energies ε1 or ε2 (εi of
= 1 or i = 2) to the above-mentioned brightness temperature S1 or S2
(In Si in the figure, i = 1 or i = 2), and a temperature measuring element 85 for determining the brightness temperature S1 or S2 measured by the temperature measuring element 85 according to a timing signal from the outside. It is composed of a data sampling circuit 86 for outputting data.

The EPR calculation unit 11A uses the brightness temperature S1 output from the photoelectric conversion unit 7A and the brightness temperature S2 output from the photoelectric conversion unit 7B based on the expressions (3a) and (4a). Then, the emissivity exponentiation ratio EPR1 is obtained. The emissivity calculation unit 13C calculates the formula (6a) based on the emissivity exponentiation ratio EPR1 obtained from the EPR calculation unit 11A and the function F1 stored in advance inside the emissivity calculation unit 13C. Emissivity ε1 is calculated while using. The temperature calculation unit 15A includes a brightness temperature S1 from the photoelectric conversion unit 7A and a brightness temperature S from the photoelectric conversion unit 7B.
2 and the emissivity ε1 from the emissivity calculation unit 13C, the temperature T of the temperature-measured body 1 is calculated using the equation (2a).
Ask for. The temperature T obtained by the temperature calculation unit 15A is
The temperature data storage / output unit 17 temporarily stores the data and outputs it to the outside.

FIG. 16 is a graph showing the relationship between the emissivity exponentiation ratio EPR and the emissivity ε2 in the above-mentioned conventional example.

FIG. 16 shows the above-mentioned Japanese Unexamined Patent Publication No. 5-126664.
It is created based on FIG. In FIG. 16, the emissivity exponentiation ratio EPR actually calculated
And the emissivity ε2 are shown by the curve X. Also, the straight line L
1 and L2 are regression lines of the above-mentioned curve X. In this conventional example, the emissivity calculation unit 13C uses the data table according to the straight lines L1 and L2 stored therein, and calculates the emissivity from the emissivity exponentiation ratio EPR1 obtained by the EPR calculation unit 11A. We are seeking ε1. In other words, it can be said that the data table based on these straight lines L1 and L2 corresponds to the function F1 of the above equation (6a).

[0026]

However, as shown by the curve X in FIG. 16 described above, the relationship between the emissivity exponentiation ratio EPR1 and the emissivity ε1 obtained by calculation or experiment is a function calculated by a complicated calculation formula. And tends to be polyvalent. For example, in FIG. 16, when the emissivity exponentiation ratio EPR1 is “1.10”, the emissivity ε1 has two values, that is, a value indicated by reference symbol LB and a value indicated by reference symbol LC. Is obviously a multi-valued function.

Therefore, when such a function is regressed by the above-mentioned straight line L2, there is a problem that the temperature measurement error increases. Specifically, when the curve X is regressed by the straight line L2, when the emissivity exponentiation ratio EPR1 is “1.10”, the error of the maximum emissivity ε1 of about | LB-LA | or | LA-LC | Since this occurs, an error will occur in the temperature measurement calculated accordingly.

The present invention has been made to solve the above-mentioned conventional problems, and is one of two radiant intensities of each spectrum of thermal radiation from a temperature-measured body having a plurality of different wavelengths.
The emissivity of the temperature-measured object at at least one of the wavelengths is obtained from the ratio of the powers of the respective calculation amounts corresponding to the respective ones, and at least one of the emissivity and the emissivity is obtained. In the multi-wavelength radiation temperature measuring method and the multi-wavelength radiation thermometer, the temperature of the object to be measured is determined from the radiation intensity of the wavelength, and a function between them for determining the emissivity from the exponentiation ratio. It is possible to suppress the relationship from becoming a multi-valued function, thereby suppressing a temperature measurement error and a calculation problem due to a plurality of obtained emissivity values, and improving the temperature measurement accuracy. An object of the present invention is to provide a multi-wavelength radiation temperature measuring method and a multi-wavelength radiation thermometer capable of performing the above.

[0029]

First, a multi-wavelength radiation temperature measuring method according to the first invention of the present application is one in which the radiation intensity of each of the spectra of the thermal radiation light from the temperature-measuring object of a plurality of wavelengths different from each other. The emissivity of the temperature-measured body at at least one of the wavelengths is calculated from the ratio of the powers of the respective calculation amounts corresponding to the two, respectively, and is calculated as at least the emissivity and the emissivity. In the multi-wavelength radiation temperature measuring method for obtaining the temperature of the temperature-measuring body from the radiation intensity of the corresponding wavelength, the degree of light absorption of the temperature-measuring body is mutually different for at least two of the wavelengths. The present invention provides a multi-wavelength radiation temperature measuring method that can achieve the above-mentioned object by having different wavelengths.

In the first aspect of the invention, the temperature-measured surface of the temperature-measured body is covered with a thin film, and at least two of the wavelengths are absorbed by the temperature-measured body. Is strong, the wavelength corresponding to the thickness of the thin film body, the other is a weak degree of light absorption, the wavelength corresponding to the thickness of the thin film body, for example, a metal oxide film Focusing on the spectral distribution of the thermal radiation of the temperature-measured body covered with the thin film body, there are two wavelengths set above so that the degree of light absorption of the temperature-measurement body is different. The present invention provides a multi-wavelength radiation temperature measuring method capable of more effectively achieving the above-mentioned object by effectively expanding the difference in the degree of light absorption.

On the other hand, the multi-wavelength radiation thermometer of the second invention of the present application responds to two of the respective radiant intensities of the spectrum of the thermal radiation light from the temperature-measuring object of a plurality of mutually different wavelengths. The emissivity of the temperature-measured body at at least one of the wavelengths is obtained from the ratio of the amount of calculation raised to the power of each wavelength, and at least the emissivity and the radiant intensity of the wavelength corresponding to the emissivity are obtained. From the above, in the multi-wavelength radiation thermometer for determining the temperature of the temperature-measured body, at least two of the wavelengths have a light absorption degree of the temperature-measurement body different from each other. Including, the spectroscopic means for obtaining a spectrum of the plurality of wavelengths different from each other from the thermal radiation light, the optical sensor for detecting the radiation intensity of these spectra, and the calculation amount corresponding to two of these radiation intensities, respectively. , Each wave In those with power and power ratio calculating means for calculating the ratio from 該累 multiplication ratio, at least one of said wavelength
And emissivity calculating means for determining the emissivity of the temperature-measuring object, and temperature calculation for calculating the temperature of the temperature-measuring object from the emissivity and the radiation intensity of a wavelength corresponding to the emissivity. By providing the means, a multi-wavelength radiation thermometer capable of achieving the above-mentioned object is provided.

In the multi-wavelength radiation thermometer according to the second aspect of the invention, the spectroscopic means obtains a spectrum of three or more of the wavelengths, and the optical sensor has three or more of these wavelengths. Detecting the radiant intensity of the spectrum of the wavelength, wherein the exponentiation ratio computing means corresponds to a combination of a plurality of types of radiant intensities that are selected from two or more of these three or more radiant intensities. One of a plurality of types for obtaining the power ratio of a plurality of types, wherein the emissivity calculation means has a smaller error of the temperature of the temperature-measured body calculated by the temperature calculation means. The above object is achieved by selecting and using one of the power ratios, and the object is further achieved by reducing the error of the emissivity. .

The principle of the present invention will be described below.

The relationship between the emissivity exponentiation ratio EPR1 and the emissivity ε1 shown by the curve X in FIG. 16 differs greatly depending on the wavelength of the spectrum of the target thermal radiation light. In addition, the relationship between the power ratio and the emissivity described above, including the relationship between the ratio of the radiant energy raised to the power of its wavelength and the emissivity as described in JP-A-5-126642, is It depends greatly on the wavelength of the spectrum of the synchrotron radiation.

However, heretofore, no technique has been disclosed as to what kind of wavelength should be selected to improve the temperature measurement accuracy. For example, the above-mentioned Japanese Patent Laid-Open No.
In order to deal with the fact that the function for obtaining the emissivity as described above becomes a multi-valued function in -126642 and Japanese Patent Application Laid-Open No. 5-164616, for example, regression is performed with the straight lines L1 and L2 as described above. However, it does not disclose what wavelength is preferable for temperature measurement accuracy.

Many experiments were conducted to investigate the relationship between the power ratio and the emissivity for the wavelengths of the spectrum of the thermal radiation from various objects to be measured, and the heat for calculating the power ratio was calculated. For two spectra with different wavelengths of synchrotron radiation, if the degree of light absorption of the temperature-measuring object is set to different wavelengths,
It has been found that the multi-valued functional element as described above is weakened.

The object of the present invention is not limited to this, but it is also possible to measure the surface temperature of the temperature-measured body covered with a thin film such as an oxide film.
In the temperature-measured body covered with the thin film body in this way, the degree of light absorption of the surface of the thin-film body or the base material of the temperature-measured body inside the thin film body is
Each of them changes relatively greatly depending on the wavelength of the spectrum. Especially,
The degree of light absorption on the surface of the thin film body changes relatively greatly. For example, an oxide film formed on the surface of a base material of a semiconductor such as metal or silicon has a wavelength having a high degree of infrared absorption. Therefore, when the temperature-measured surface of the temperature-measured body is covered with a thin film body, one of the at least two wavelengths that makes the degree of light absorption different has a degree of light absorption of the temperature-measured body. It is conceivable that the wavelength is strong and depends on the thickness of the thin film body, and the other wavelength is weak and the degree of light absorption is weak and depends on the thickness of the thin film body. By doing so, the difference in the degree of light absorption between these two wavelengths can be easily set to be larger.

For example, as shown in FIG. 2, the wavelength λ1 is set to 4.0.
When the wavelength is λ2 and the wavelength λ2 is 2.0 μm, the relationship between the emissivity exponentiation ratio EPR1 and the emissivity ε1 of a certain object to be measured is as shown in the graph of FIG.

Here, the imaginary number i, that is, (i ² = -1) is defined, and the complex refractive index N is defined by (N = n-ik).
Then, the values of n and k of the base material of the temperature-measured body and the oxide film formed on the surface of the base material are as shown in FIG. 2, for example. In the complex refractive index, the larger the value of k, the greater the degree of light absorption. Here, the degree of light absorption in the oxide film on the surface of the temperature-measured body is significantly larger at the wavelength λ2 than at the wavelength λ1. In addition, in FIG. 2, the base material of the temperature-measuring object,
The temperature of the oxide film on the surface of the base material is around 800 ° C.

For example, under the condition of FIG. 2, the characteristic of the emissivity ε is as shown in FIG. 1, but if the difference in the degree of light absorption between the two wavelengths λ1 and λ2 becomes large as described above,
The multi-functional tendency is weakened.

For example, in the curve A showing the relationship between the emissivity exponentiation ratio EPR1 and the emissivity ε1 in FIG. 1, points A4 to A6 are polyvalent functions, but points A4 to A1 are The unit price is functional. For example, when the curve A between the point A4 and the point A1 is regressed by the straight line LA1, the emissivity ε1 of the curve A and the straight line LA1 is
Is smaller than that in the case of regressing with the straight line L2 in FIG. 16 described above, for example. Therefore, even if the emissivity ε1 is obtained from the emissivity exponentiation ratio EPR1 based on the relationship such as the straight line LA1, the error is smaller than that obtained from the curve A.

As described above, according to the first invention and the second invention, the functional relationship for obtaining the emissivity from the power ratio is set by setting the wavelength of the spectrum to be used more effectively. It is possible to suppress a multi-valued function, thereby eliminating a temperature measurement error and a calculation problem due to a plurality of obtained emissivity values, and improving the temperature measurement accuracy. .

[0043]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 is a block diagram showing a configuration of a first embodiment of a multi-wavelength radiation thermometer to which the first invention and the second invention are applied.

In the present embodiment, the surface temperature of the temperature-measured body 1 is measured by measuring the brightness temperatures S1 and S2 of the two λ1 and λ2 wavelengths of the heat radiation from the temperature-measured body 1. are doing. FIG. 3 and FIG. 14 of the above-mentioned conventional example.
As is clear from the comparison of the above, the present embodiment differs from the conventional example in the spectroscopic units 5A and 5B and the emissivity calculation unit 13A. The conditions of the temperature-measured body 1 are as shown in FIG.

First, the spectroscopic unit 5A of the present embodiment is used as the optical filter 82 of the spectroscopic unit 5 of FIG.
An optical filter 82 that transmits light of 4.0 μm is used. In addition, the spectroscopic unit 5B of the present embodiment uses the optical filter 82 that transmits light of 2.0 μm.

As described above, since the temperature measurement target 1 and the conditions of the wavelength λ1 and the wavelength λ2 are set, in the present embodiment,
The relationship between the emissivity exponentiation ratio EPR1 and the emissivity ε1 is as shown in the graph of FIG. Further, in contrast to the emissivity calculating unit 13C of the conventional example described above, the emissivity calculating unit 13A of the present embodiment includes a data table according to the straight line LA1 that regresses the curve A of FIG. Further, the emissivity calculating unit 13A obtains the emissivity ε1 from the emissivity exponentiation ratio EPR1 output from the EPR calculating unit 11A using such a data table.

As described above, in the present embodiment, the emissivity exponentiation ratio E shown by the curve A in FIG.
According to the relationship between PR1 and emissivity ε1, the emissivity ε1 is obtained from the emissivity exponentiation ratio EPR1 by using the straight line LA1 that has regressed with respect to the curve A and has a smaller error. Therefore, it is possible to suppress the temperature measurement error of the finally obtained temperature T and the problem in the calculation, and to improve the temperature measurement accuracy.

FIG. 4 is a block diagram showing the configuration of a second embodiment of a multi-wavelength radiation thermometer to which the first invention and the second invention are applied.

Also in this embodiment, the conditions of the temperature-measured body 1 are as shown in FIG. Further, in contrast to the conventional example and the first embodiment described above, the second embodiment is
The heat radiation from the temperature-measured body is dispersed into three wavelengths λ1, λ2 and λ3 which are different from each other, and the temperature is measured. That is, in the second embodiment, in addition to the wavelength λ1 of 4.0 μm and the wavelength λ2 of 2.0 μm, the wavelength λ3 of 1.4 μm is also targeted, and the spectroscopic unit 5C for the added wavelength λ3 is used. And a photoelectric conversion unit 7C are provided. The configuration of the spectroscopic unit 5C is the same as that of the spectroscopic unit 5 in FIG. 15, and the optical filter 82 that transmits light having a wavelength of 1.4 μm is used. The configuration of the photoelectric conversion unit 7C is the same as that of the photoelectric conversion unit 7 in FIG. Here, based on each of the equations (1) to (7) described above, a series of equations listed below can be obtained in order.

E3 = ε3 · exp {−C2 / (λ3 · T)} (1c) 1 / T = 1 / S3 + (λ3 / C2) ln (ε3) (2c)

[0052]

(Equation 5)

The brightness temperatures S1 to S3 detected by the photoelectric conversion units 7A to 7C are individually input to the EPR calculation unit 11B used in this embodiment. The EPR calculation unit 11B mainly uses the equations (3a) to (3).
Based on the equation (c) and the equations (4a) to (4b), data tables corresponding to regression lines LA and LB of FIG. 12 as described later are provided, and emissivity exponentiation ratios EPR1 and EPR2 are respectively used by using these tables. Looking for.

Here, regarding the two emissivity exponentiation ratios EPR1 and EPR2 output from the EPR calculation unit 11B, the error of the brightness temperature S2 is obtained through the function F1 of the expression (6a) and the function F2 of the expression (6b). , Emissivity ε1 and ε
Consider the error exerted on 2 and the error exerted on the temperature T finally obtained. In the present embodiment, the emissivity exponentiation ratio EPR1 or EPR2 and the function F1 or F2 are selected while considering these differences.

Here, the error exerted on the temperature T through the function F1 is ΔT1, and the error exerted on the temperature T through the function F2 is ΔT2. Also, the brightness temperature S
By obtaining the magnitudes of the errors ΔT1 and ΔT2 due to the change (error) of 2, the degree of change of the temperature T due to the change of the brightness temperature S1 is evaluated.

First, the brightness temperature S2 is {S2. (1 + Δ
S)}, the emissivity exponentiation ratio EPR1 becomes {EP
R1 · (1 + ΔEPR)}. Then, the following equation can be obtained from the equations (3a) and (4a).

ΔEPR = exp {− (C2 · ΔS / S2)} − 1 (8)

If {(C2 / S2) .ΔS} is small enough to be ignored as compared with "1", the above equation (8) can be approximated to the following equation.

ΔEPR = −C2 · ΔS / S2 (9)

Next, the emissivity exponentiation ratio EPR1 is {EPR1
When it changes to (1 + ΔEPR)}, the emissivity ε2 changes to {ε2 · (1 + Δε)}. Further, the relationship between the emissivity exponentiation ratio EPR1 and the emissivity ε1 is expressed by the equations (3a) and (4a) described above. At this time, the following relationship is established between the emissivity error Δε and the emissivity exponentiation ratio error ΔEPR.

Δε = F1 (EPR1) · {EPR1 / F1 (EPR1)} · ΔEPR (10)

Further, the rate of change of the temperature T calculated while correcting the emissivity by changing the emissivity by an error Δε is {T · (1 + ΔT1)}. Then, the error ΔT
The following relationship holds between 1, Δε, and ΔS.

ΔT1 = − {(λ2 · T) / C2} · Δε + (T / S2) · ΔS ... (11)

Therefore, it can be understood from the above equations (8) to (11) that the following relationship is established between the error ΔT1 and the error ΔS.

ΔT1 / ΔS = (T / S2) [λ2 · F1 (EPR1) · {EPR1 / F1 (EPR1)} + 1] (12a)

Similarly, the following relationship is established between the error ΔT2 and the error ΔS.

ΔT2 / ΔS = (T / S2) [λ2 · F2 (EPR2) · {EPR2 / F2 (EPR2)} + 1] (12b)

When these equations (12a) and (12b) are obtained, it can be considered as follows. That is, when the brightness temperature S changes by a constant amount ΔS, the above (12a)
The (ΔT1 / ΔS) obtained by the equation is compared with the (ΔT2 / ΔS) obtained by the equation (12b). At this time,
When (ΔT1 / ΔS) is smaller, the emissivity exponentiation ratio EP
Using E1, the emissivity ε1 obtained by using the function F1 has a smaller error than using the emissivity exponentiation ratio EPR2, the function F2, and the emissivity ε2. On the other hand, (ΔT2 / Δ
S) is smaller, the emissivity exponentiation ratio EPR2, the function F
The error is smaller when 2 and emissivity ε2 are used.

Based on this concept, the emissivity calculator 13B of this embodiment is composed of a calculation selection determiner 41 and an emissivity calculator 42, as shown in FIG. In this embodiment, the calculation selection determination unit 41 stores the value of the error ΔT1 when the error ΔS changes by a constant amount as a data table for each value of the emissivity exponentiation ratio EPR1. Further, the value of the error ΔT2 when the error ΔS changes by a fixed amount is stored as a data table for each value of the emissivity exponentiation ratio EPR2. The calculation selection determination unit 41 uses these data tables to input the radiation power ratio E
Of PR1 and EPR2, a signal E is generated for selecting one radiation power ratio such that the error | ΔT1 | or | ΔT2 | of the temperature T calculated by the temperature calculation unit 15B becomes smaller. Is output to the emissivity calculator 42 and the input temperature storage selection unit 51A of FIG. 6 described later. The emissivity calculator 42 calculates the error of the temperature T according to the signal E.
Using the radiation power ratio EPR1 or EPR2 with which ΔT1 | or | ΔT2 | becomes smaller, the expression (6a) or the expression (6b) is selected and used to obtain the emissivity ε.

Next, as shown in FIG. 6, the temperature calculator 15B comprises an input temperature memory selector 51A and a temperature calculator 52. First, when the emissivity calculator 42 selects the emissivity exponentiation ratio EPR1 according to the signal E from the calculation selection determination unit 41, the input temperature calculation selection unit 51A selects the brightness temperature S1 according to the signal E. On the other hand, when the emissivity calculator 42 selects the emissivity exponentiation ratio EPR2 by the signal E, the input temperature storage selection unit 51A selects the brightness temperature S2 according to the signal E and outputs it to the temperature calculator 52. . The temperature calculator 52 uses the brightness temperature S1 selected by the input temperature storage selection unit 51A.
Alternatively, according to S2 and the emissivity ε1 or ε2 obtained by the emissivity calculator 42, the temperature T is calculated using the equation (2).

Next, FIG. 7 shows the first invention and the second invention.
It is a block diagram which shows the structure of the multi-wavelength radiation thermometer of 3rd Embodiment to which the invention was applied.

Also in the third embodiment, similar to the second embodiment, the spectrum of the heat radiation light from the temperature-measured body 1, particularly three wavelengths, is used. The target temperature-measured body 1 is as shown in FIG. 2 as in the second embodiment.

FIG. 8 is a block diagram showing the structures of a spectroscopic unit and a photoelectric conversion unit used in the third embodiment.

As shown in FIG. 8, the spectroscopic unit 5W
Is composed of a condensing optical unit 71, an optical filter assembly 72 having a large number of optical filters 72a, and a step motor 73. The condensing optical unit 71 condenses the spectrum of the heat radiation light from the temperature-measured body 1 on the temperature measuring element 85 of the photoelectric conversion unit 7W. The optical filter assembly includes a plurality of optical filters 72a that are driven by a step motor 73.
Any one of the above is indexed to the optical path from the condensing optical section 71 to the temperature measuring element 85. The optical filter assembly 7
The two large numbers of the optical filters 72a are set so that the wavelengths of the transmitted spectra are different from each other. In particular, among these optical filters 72a, one that transmits a wavelength λ1 of 4.0 μm, one that transmits a spectrum of a wavelength λ2 of 2.0 μm, and one that transmits a spectrum of a wavelength λ3 of 1.4 μm. Is prepared. Therefore, the same function as the three spectroscopic sections 5A to 5C of the second embodiment described above can be obtained with only one spectroscopic section 5W.

Next, the photoelectric conversion unit 7W has a temperature measuring element 8
5 and a data sampling circuit 86. These temperature measuring element 85 and data sampling circuit 86
Is the same as that described above with reference to FIG.

The EPR calculation unit 11C of this embodiment is shown in FIG.
As shown in, the input data storage unit 62 is provided on the input side of the EPR calculation unit 11B of the second embodiment. In the third embodiment, while the optical filter assembly 72 of the spectroscopic unit 5W is indexed three times, the brightness temperatures S1 to S3 of the wavelengths λ1 to λ3 are measured by the photoelectric conversion unit 7.
It is detected by W. Therefore, the input data storage unit 62 is
The brightness temperatures S1 to S3 sequentially input in this manner are stored and output to the EPR calculation unit 11B.

FIG. 10 is a block diagram showing the structure of the temperature calculation unit 15C.

As shown in FIG. 10, the temperature calculator 15C
Is composed of an input temperature storage selection unit 51B and a temperature calculation unit 52. The temperature measuring device 5 of the third embodiment
The item 2 is similar to that of the second embodiment.
Further, the input temperature storage selection section 51B has a function of storing the brightness temperatures S1 to S3 sequentially input while indexing the optical filter assembly 72.
This is provided in the input temperature memory selection unit 51A of the embodiment. Other functions of the input temperature storage unit 51B,
For example, the operation according to the signal E is the same as that of the input temperature memory selection unit 51A of the second embodiment.

Here, in the second and third embodiments, the photoelectric conversion units 7A to 7B,
The error ΔS of the brightness temperature at 7 W or the like is 0.5%. Under the conditions, or the conditions shown in FIG. 2, when the temperature T of the temperature-measured body 1 is 1073 ° K (800 ° C.) in absolute temperature,
As shown in FIG. 11, the emissivity exponentiation ratio EPR for each oxide film thickness
1, the relationship between | ΔT1 / ΔS | regarding the error, the emissivity exponentiation ratio EPR2, and | ΔT2 / ΔS | regarding the error are evaluated. Also, based on this evaluation, the above-mentioned switching in the calculation selection determination unit 41 is considered and made.

In the second and third embodiments, in FIG. 1, | ΔT1 / ΔS |
When smaller than 2 / ΔS |, the emissivity exponentiation ratio EPR
1, the emissivity ε1 is calculated using the function F1. On the other hand, when | ΔT2 / ΔS | is smaller than | ΔT1 / ΔS |, the emissivity ε2 is calculated using the emissivity exponentiation ratio EPR2 and the function F2.

In the case of FIG. 11, the emissivity exponentiation ratio EPR1
Is greater than or equal to “0.024”, | ΔT1 / ΔS | is smaller than | ΔT2 / ΔS |, so the emissivity ε1 is obtained using the emissivity exponentiation ratio EPR1 and the function F1. On the other hand, when the emissivity exponentiation ratio EPR1 is smaller than “0.024”, | ΔT2 / is smaller than | ΔT1 / ΔS |
Since ΔS | is smaller, the emissivity exponential ratio EPR2 and the emissivity ε2 using the function F2 are used. In FIG. 12 described later, EPR1 is "0.
The position of 024 "is the point A3. The position of ERP2 when the EPR1 is" 0.024 "is almost the point B2.

FIG. 12 shows the second embodiment and the third embodiment.
It is a graph which shows the relationship between the emissivity power ratio and the emissivity in the embodiment.

FIG. 12 shows a graph centered on the data shown in FIG. Here, in FIG. 12, the relationship between the emissivity exponentiation ratio EPR1 and the emissivity ε1 for the wavelengths λ1 and λ2 is shown by the curve A, which is the same as the curve A in FIG. The curve B shows the relationship between the emissivity exponent ratio EPR2 and the emissivity ε2 with respect to the wavelengths λ2 and λ3.

Here, the curve A has a unit price function in the section from the point A1 to the point A4, and has a multivalue function from the points A3 to A6. In the curve B, points B1 to B3 are unit price functions, and points B3 to B4 to points B5 are polyvalent functions. In this embodiment, according to such a point, or according to the selection of the function F1 or F2 described above with reference to FIG. 11, in the section from the point A5 to the point A4 of the unit price functional section of the curve A, the regression is performed. The straight line LA is used, and the regression line LB is used in the section from the point B2 to the point B1 of the unit price functional section of the curve B.
Emissivity ε (ε1 or ε2) using PR1 or EPR2
Seeking. The regression lines LA and LB are switched at points A4 and B2 between the regression lines LA and LB. The calculation selection determination unit 41 selects the regression line LA or LB. Such selection is performed as described above using the equation (12a) or the equation (12b). Data tables corresponding to the regression lines LA and LB are stored in the emissivity calculator 42.

In FIG. 12, point A2 and point A
4, the thickness of the oxide film at each point B2 is
It is 0.04 μm, 0.086 μm, and 0.086 μm.

FIG. 13 shows the second embodiment and the third embodiment.
6 is a graph showing the relationship between emissivity and temperature measurement error in the embodiment.

In FIG. 13, in the curve C from the point C1 to the point C2, the emissivity exponentiation ratio EPR1 and the function F1 are shown at C.
The temperature measurement error (T · ΔT1) of the temperature T based on the emissivity ε1 obtained by using is shown. On the other hand, from point C2 to point D
For curve D up to 1, the emissivity exponent ratio EPR2 and the function F
2 and the temperature measurement error (T · ΔT2) of the temperature T obtained based on the emissivity ε2 obtained by these.

According to the second embodiment and the third embodiment, since the emissivity ε1 or ε2 or the like is selectively used so as to reduce the error, as shown in FIG. The temperature measurement error can be suppressed to ± 5 ° C.

The first embodiment described above has two,
The second and third embodiments described above use three different wavelength spectra, but the present invention is not limited to this. For example, the number of types of spectral wavelengths used is four or more, and the number of emissivity power ratios used is three.
There may be more than one. Even in such a case, it is desirable that one of the wavelengths has a significantly higher degree of light absorption of the temperature-measured body than the other wavelengths or a significantly weaker degree of light absorption than the other wavelengths. In addition, when using the spectroscopy of more wavelengths in this way, if the structure like the spectroscopic unit 5W shown in FIG. 8 is used, the number of the condensing optical unit 71 and the photoelectric conversion unit 7W can be further reduced. Therefore, it is advantageous in terms of cost.

[0090]

As described above, according to the first invention and the second invention, two of the radiant intensities of the respective spectra of the thermal radiation from the temperature-measuring object having a plurality of wavelengths different from each other are provided. The emissivity of the temperature-measured body at at least one of the wavelengths is calculated from the ratio of the powers of the respective wavelengths raised to the respective powers, and at least the emissivity and the wavelength corresponding to the emissivity are obtained. In the multi-wavelength radiation temperature measuring method and the multi-wavelength radiation thermometer, which are adapted to obtain the temperature of the temperature-measuring object from the radiation intensity, the functional relation between them for obtaining the emissivity from the power ratio. It is possible to suppress the temperature measurement error and the calculation problem due to a plurality of obtained emissivity values, thereby improving the temperature measurement accuracy. Get the excellent effect that you can Door can be.

[Brief description of drawings]

FIG. 1 is a graph showing a relationship between an emissivity exponentiation ratio and an emissivity showing a principle of a multi-wavelength radiation temperature measuring method of a first invention and a multi-wavelength radiation thermometer of a second invention of the present application.

FIG. 2 is a diagram showing an example of conditions of a temperature measurement target object of the first invention and the second invention and an example of a wavelength of a spectrum of the thermal radiation light.

FIG. 3 is a block diagram showing a configuration of a first embodiment of a multi-wavelength radiation thermometer to which the first invention and the second invention are applied.

FIG. 4 is a block diagram showing a configuration of a second embodiment of a multi-wavelength radiation thermometer to which the first invention and the second invention are applied.

FIG. 5 is a block diagram showing a configuration of an EPR calculation unit used in the second embodiment.

FIG. 6 is a block diagram showing a configuration of a temperature calculation unit used in the second embodiment.

FIG. 7 is a block diagram showing a configuration of a third embodiment of a multi-wavelength radiation thermometer to which the first invention and the second invention are applied.

FIG. 8 is a block diagram showing a configuration of a spectroscope and a photoelectric conversion unit used in the third embodiment.

FIG. 9 is a block diagram showing the configuration of an EPR calculation unit used in the third embodiment.

FIG. 10 is a block diagram showing a configuration of a temperature calculation unit used in the third embodiment.

FIG. 11 is a diagram showing an emissivity exponentiation ratio and a temperature measurement error in the second embodiment and the third embodiment.

FIG. 12 is a graph showing the relationship between the emissivity exponentiation ratio and the emissivity in the second embodiment and the third embodiment.

FIG. 13 is a graph showing a temperature measurement error in the second embodiment and the third embodiment.

FIG. 14 is a block diagram showing a configuration of a conventional multi-wavelength radiation thermometer.

FIG. 15 is a block diagram showing a configuration of a spectroscopic unit and a photoelectric conversion unit used in the conventional example.

FIG. 16 is a graph showing the relationship between the emissivity power ratio and the emissivity in the conventional example.

[Explanation of symbols]

 5A to 5E, 5W ... Spectroscopic unit 7A to 7C, 7W ... Photoelectric conversion unit 11A to 11C ... EPR calculation unit 13A to 13C ... Emissivity calculation unit 15A to 15C ... Temperature calculation unit 17 ... Temperature data storage output unit 41 ... Calculation selection unit 41 Judgment part 42 ... Emissivity calculator 51A, 51B ... Input temperature memory selection part 52 ... Temperature calculator 62 ... Input data storage part 71, 81 ... Condensing optical part 72 ... Optical filter aggregate 72a, 82 ... Optical filter 73 ... Step motor 85 ... Temperature measuring element 86 ... Data sampling circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takatoshi Goto 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Co., Ltd. Chiba Works (72) Inventor Shinichi Takechi 1 Kawasaki-cho, Chuo-ku, Chiba Chiba Chiba Steel Works, Ltd.

Claims (4)

[Claims] 1. A ratio of a calculation amount corresponding to each of two radiant intensities of a spectrum of thermal radiation from a temperature-measured object having a plurality of different wavelengths raised to each wavelength, The emissivity of the temperature-measuring object at at least one of the wavelengths is determined, and the temperature of the temperature-measuring object is determined at least from the emissivity and the radiation intensity of the wavelength corresponding to the emissivity. In the multi-wavelength radiation temperature measuring method, the degree of light absorption of the temperature-measured body is different from each other for at least two of the wavelengths. 2. The temperature-measured surface of the temperature-measured body is covered with a thin film, and one of at least two of the wavelengths is a light absorption of the temperature-measured body. A multi-wavelength radiation having a strong degree and a wavelength corresponding to the thickness of the thin film body, and the other wavelength having a weak degree of the light absorption and a wavelength according to the thickness of the thin film body. How to measure temperature. 3. A ratio of arithmetic powers corresponding to two of the respective radiation intensities of the spectrum of the thermal radiation from the temperature-measuring object at a plurality of different wavelengths raised to the respective powers, The emissivity of the temperature-measuring object at at least one of the wavelengths is determined, and the temperature of the temperature-measuring object is determined at least from the emissivity and the radiation intensity of the wavelength corresponding to the emissivity. In the multi-wavelength radiation thermometer, for at least two of the wavelengths, a plurality of different ones from the thermal radiation light are included, including a spectrum in which the degree of light absorption of the temperature-measured body is different from each other. Spectral means for obtaining a spectrum of wavelengths, an optical sensor for detecting the radiation intensity of these spectra, and an exponentiation ratio calculation for obtaining a ratio of the calculation amounts corresponding to two of these radiation intensities raised to the respective wavelengths. means An emissivity calculation means for obtaining an emissivity of the temperature-measured body at at least one of the wavelengths from the power ratio, the emissivity, and the radiant intensity of a wavelength corresponding to the emissivity, A multi-wavelength radiation thermometer, comprising: a temperature calculation means for calculating the temperature of a temperature-measured body. 4. The spectroscopic device according to claim 3, wherein the spectroscopic means obtains spectroscopic light of three or more wavelengths, and the optical sensor detects radiation intensity of spectroscopic light of these three or more wavelengths. The exponentiation ratio calculating means selects two out of three or more of these radiant intensities, and obtains a plurality of kinds of exponential ratios corresponding to a combination of a plurality of mutually different radiant intensities. The emissivity calculating means selects one of the power ratios of a plurality of types such that the error of the temperature of the temperature-measuring object calculated by the temperature calculating means becomes smaller. A multi-wavelength radiation thermometer, characterized in that the emissivity is obtained by using the radiation thermometer.