JPH0933352A - Method for measuring radiation temperature and radiation thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the measuring precision by finding the relation of emissivity ratio to emissivity of P-polarized and S-polarized spectral components of a heat radiant light emitted in the direction of the radiating angle of polarizing angle (Brewster angle) of a thin film. SOLUTION: An emissivity relation arithmetic device 14 finds the functional relation of P-polarized emissivity to emissivity and the functional relation of S-polarized emissivity to emissivity, and the resulting data relating to the functional relations are stored in an emissivity function memory device 15. When the temperature of the surface of an object 1 to be temperature-measured is found, P-polarized emissivity is found from a prescribed expression by use of the P-polarized emissivity ratio obtained by an emissivity ratio arithmetic device 12A on the basis of a prescribed expression. By use of the S-polarized emissivity ratio, S-polarized emissivity is found from a prescribed expression. The temperature is found according to the Wien expression by use of the P- polarized and S-polarized emissivities.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to radiance of P-polarized light of a specific wavelength component spectrum of thermal radiation emitted from a surface of an object to be measured coated with a thin film in a direction of a specific radiation angle, and S. A radiant temperature measuring method and a radiant thermometer for detecting the radiance of polarized light and obtaining the temperature of the surface of the object to be measured from the radiances of the P-polarized spectral component and the S-polarized spectral component radiance. An error in detecting the intensity of heat radiation from the surface of the temperature-measuring object, further suppressing the degree of influence on the temperature of the temperature-measured object surface that is required, and further improving the accuracy of the required temperature, The present invention relates to a radiation temperature measuring method and a radiation thermometer capable of simplifying an operation to be performed and a device to be used by taking care so that sequential calculation is not performed in the process of obtaining the temperature.

[0002]

2. Description of the Related Art Conventionally, the temperature of the surface of an object to be measured has been measured from the heat radiation from the surface of the object to be measured based on Wien's law. For example, a radiant temperature measuring method and a radiant thermometer using the Wien's radiance law, in which the radiance (radiant energy) of the thermal radiant light changes according to the temperature of the surface of the object to be measured, have been conventionally used. . Alternatively, the radiation temperature measuring method using the Wien's displacement law or a radiation thermometer is used, in which the wavelength at which the radiance (radiant energy) of the thermal radiation changes to maximum depending on the temperature of the surface of the object to be measured. Has been.

Further, in recent years, a plurality of radiances having different wavelengths and polarization angles are detected, and the emissivity on the surface of the object to be measured is corrected based on the detected radiance, and the temperature of the surface of the object to be measured is measured. There is known an emissivity-corrected temperature measurement technique that measures more accurately.

For example, in Japanese Unexamined Patent Publication (Kokai) No. 5-273045, while calculating the radiances of two thermal radiations having different polarization angles, particularly the radiances of P-polarized light and S-polarized light, the polarization emissivity of these two is calculated. , A technique for obtaining the temperature of the surface of a temperature-measured object is disclosed. In JP-A-5-273045, the surface of the object to be measured is assumed to be covered with a thin film such as an oxide, and the temperature measurement error of the surface of the object to be measured is improved. In addition, the radiance of the thermal radiation light emitted in the direction of the Brewster angle θb of the thin film on the surface of the object to be measured is detected.

Here, a conventional radiation temperature measuring method and a radiation thermometer will be described in this order, focusing on the temperature measuring technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-273045.

First, "P-polarized light", "S-polarized light", and "Brewster angle θb" according to the present invention will be described together with the conventional radiation temperature measuring method and radiation thermometer described below.

FIG. 8 is a side view showing a catadioptric path of a light beam incident on a sample on which an oxide film is formed.

In FIG. 8, a sample 3 having a two-layer medium structure, which is a base material 3b of stainless steel (SUS304) on which an oxide thin film 3a is formed, is targeted. In FIG. 8, a reflection path and a refraction path of incident light from the air with an incident angle θ are shown for such a sample 3. P-polarized LP incident from the left side of FIG.
Incident light LI including and S-polarized light LS first passes through the linear polarization filter 80. The S polarization LS is removed by the linear polarization filter 80, and only the P polarization LP is incident on the sample 3.

Here, the P-polarized light is, for example, a linearly polarized light component of light which is perpendicular to the reflecting surface of the sample 3 in FIG. 8 and which is parallel to a plane including an incident light ray (this plane is hereinafter referred to as an incident surface). Is. The S-polarized light is a linearly polarized light component perpendicular to the P-polarized light. Further, although it is air in FIG. 8, the medium into which the incident light beam is incident is not limited to this, and is hereinafter referred to as medium 1. Not limited to the case of stainless steel as described above, the thin film 3a of the sample 3 is referred to as the medium 2 and the base material 3b is referred to as the medium 3.

Here, when the incident light beam LI that has passed through the linear polarization filter 80 is incident on the sample 3 at an incident angle θ, the reflection angle θ is the same as the incident angle θ on the surface of the thin film 3a. A reflected ray LR1 that is reflected is obtained.

On the other hand, the incident light beam LI thus incident at the incident angle θ is refracted at the refraction angle φ at the boundary surface between the air (medium 1) and the thin film 3a (medium 2), so that the light beam passes through the thin film 3a. move on. Further, this light ray traveling through the thin film 3a is reflected at the boundary surface between the thin film 3a (medium 2) and the base material 3b (medium 3), and further, air (medium 1) and the thin film 3a.
It is refracted at the interface with (medium 2) and becomes a reflected light ray LR2.

When a medium 1 is incident at an incident angle θ and the refraction angle at the interface between the medium 1 and the medium 2 is φ, the relative refractive index between the medium 1 and the medium 2 is If N is a real number, the following equation is generally established.

(Sin θ / sin φ) = N (1)

Further, the reflectance at the boundary surface between the medium 1 and the medium 2 of P-polarized light incident at the incident angle θ can be expressed by the following equation.

Rp = | {tan (θ−φ) / {tan (θ + φ)} | ² (2)

Here, the aforementioned Brewster angle θb is
It is defined as the above-mentioned incident angle θ at which the reflectance Rp of the above formula (2) becomes “0”. Therefore, with such a Brewster angle θb, the right side of the above equation (2) is “0”, so that the incident angle θ and the refraction angle φ at this time satisfy the following equations. The Brewster angle θb largely depends on the physical properties of the sample 3 such as the material and surface condition.

Tan (θb + φ) = ∞ (3a) θb + φ = (π / 2) (3b)

That is, the air and the thin film 3a shown in FIG.
Considering the reflected ray LR1 at the boundary surface between and, when the incident angle θ becomes the Brewster angle θb, the reflected ray LR1 does not exist, for example, as shown in FIG. 9 (θ ′ = θb). Here, the above equation (3b) is
It can be transformed as in the following equation (3c). Further, the following equation (4) can be obtained from the equation (3c) and the equation (1).

Θb = (π / 2) −φ (3c) tan θb = N (4)

Here, since the boundary surface where the light is reflected usually has unevenness (surface state), and the medium 2 after the light has passed through the boundary surface has internal light absorption and the like. Generally, the relative refractive index of the medium 2 can be expressed by the following equation.
In the following equation, i is an imaginary number, and n and k are a real part and an imaginary part of the refractive index, respectively. Note that k can also be considered as a damping constant.

N = n + ik (5)

Strictly speaking, the reflectance of P-polarized light is not always "0" even at the incident angle θ (that is, θ = θb) where the above-mentioned expression (4) is established. However, in the following description, the real part of the complex refractive index of the medium 2 is Re
In the case of (N), the incident angle defined by the following equation will be referred to as Brewster angle θb.

Tan θ = Re (N) (6)

A conventional radiation temperature measuring method will be described below, centering on the temperature measuring technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 5-273045.

In this radiation temperature measuring method, first, a specific wavelength λ1 component radiated in the direction of Brewster's angle θb of the thin film from the surface of a temperature-measured object such as a metal covered with a thin film such as a metal oxide film. The radiance Sp of the P-polarized thermal radiation light and the radiance Ss of the S-polarized thermal radiation light of the spectrum are detected. Further, the temperature T of the surface of the object to be measured is obtained from the P-polarized spectral component radiance Sp and the S-polarized spectral component radiance Ss.

Here, the emissivity of the P-polarized spectral component is εp, and the emissivity of the S-polarized spectral component is εs. Then, the above-mentioned radiances Sp and Ss that are almost equal to the brightness temperature are obtained.
And the true temperature T of the object to be measured, there is a Wien's equation consisting of the following two equations. In the following equation,
C2 (= 14388 μm · K) is Planck's second constant.

(1 / T) = (1 / Sp) + (λ1 / C2) ln (εp) (7) (1 / T) = (1 / Ss) + (λ1 / C2) ln (εs) (8)

From the above equations (7) and (8), T
By eliminating, the following equation can be derived.

(1 / Ss)-(1 / Sp) = (λ1 / C2) ln (εp / εs) (9)

Since the emissivity ratio in the above equation (9), that is, (εp / εs) does not depend on the temperature T, the following equation holds.

Εp = (εp0 / εs0) · εs (10)

On the other hand, the following two equations can be obtained by modifying the equations (7) and (8) respectively.

Εp0 = exp [(C2 / λ1) {(1 / T)-(1 / Sp0)}] (11) εs0 = exp [(C2 / λ1) {(1 / T)-(1 / Ss0 )}]… (12)

Here, there is generally a fixed relationship between the emissivity εp for P-polarized light and the emissivity εs for S-polarized light. If this constant relationship is defined as a correlation function g0, it can be expressed as the following equation. Here, such a correlation function g0 can be obtained in advance. According to such a correlation function g0 and the following equation (14), it is possible to obtain the other from the emissivity εp and the emissivity εs.

Εp = g 0 (εs) (13)

Conventionally, in the radiation temperature measuring method, steps S1 to S5 listed below are sequentially performed. Particularly, steps S2 to S5 are repeatedly executed until the temperature T is obtained.

Step S1: Initial setting of temperature T (T1 is set as an initial value for the temperature T. That is, (T = T
1). In addition, the initial values of the radiance Sp and the radiance Ss are respectively the actually detected radiance Sp0,
And radiance Ss0.

Step S2: Emissivity εp0 and εs0 are obtained. That is, the given radiance Sp and radiance Ss, and the given temperature T are substituted into the above equations (11) and (12) to obtain the emissivity εp0 and the emissivity ε.
Find s0.

Step S3: Emissivity εp and emissivity ε
Find s. That is, the emissivity εp and the emissivity εs that simultaneously satisfy the expressions (10) and (13) are obtained.

Step S4: Temperature T (= T (k + 1))
Ask for. That is, the emissivity εp obtained in step S3
And emissivity εs, and preset radiances Sp and Ss are used, and the temperature T (= T (k + 1)) is calculated using the equations (7) and (8).

Step S5: Determination of completion of calculation of temperature T.
That is, regarding the temperature T obtained in step S4, (T
If (k + 1)) ≠ (T (k)), another (T = T
(K + 1)), a series of steps S2 to S5 is executed again from step S2. On the other hand, (T (k + 1) =
If T (k)), it is determined that the temperature T has been obtained, and the series of operations described above is completed.

As described above, in the conventional radiation temperature measuring method, a large number of processes are sequentially executed as in steps S1 to S5. In particular, when obtaining the temperature T, steps S2 to S5 are repeatedly executed many times depending on the case. Thus, the temperature T can be obtained with higher accuracy while correcting the emissivity.

FIG. 10 is a block diagram showing the structure of a conventional radiation thermometer.

FIG. 10 shows the construction of a radiation thermometer based on the conventional radiation temperature measuring method based on the above-described measurement principle. As shown in FIG. 10, the radiation thermometer comprises a detection device 4C, a temperature calculation device 9C, and a temperature data storage / output device 19. Also, the temperature calculation device 9
C is a sequential calculation unit 51, an initial setting unit 52, a resetting unit 53, a data storage device 55, an emissivity calculation unit 57,
The temperature calculation unit 58 and the process determination unit 59 are included.

As shown in FIG. 11, the detecting device 4C is composed of detecting portions 4a and 4b. Each of the detection units 4a and 4b includes a linear polarization filter 80, a condensing optical unit 81, an optical filter 82, a temperature measuring element 85, and a data sampling circuit 86.

First, in the detection section 4a, the linear polarization filter 80 extracts P-polarized light. On the other hand, in the case of the detection unit 4b, the linear polarization filter 80
Is for extracting S-polarized light.

The condensing optical section 81 condenses the heat radiation light from the surface of the object 1 to be measured to the temperature measuring element 85 described later. The optical filter 82 is an interference filter that disperses a specific wavelength λ component, and specifically disperses infrared light having a specific wavelength.

Next, the temperature measuring element 85 has a P of the specific wavelength λ component spectrum which is condensed by the condensing optical section 81.
Brightness temperature S according to the radiance of polarized light or S-polarized light
Detect p or Ss. The data sampling circuit 86 temporarily stores and outputs the data of the brightness temperature Sp or Ss measured by the temperature measuring element 85 according to a timing signal from the outside.

Next, in the temperature calculation device 9C, the processes shown in steps S1 to S5 described above are performed. The correlation function g0 described above in the equation (13) used in such processing is previously obtained and stored in the data storage device 55 as table data. In the initial setting section 52, the process of step S1 described above is performed. The sequential calculation unit 51 performs the process of step S2 described above. In the emissivity calculator 57,
The process of step S3 described above is performed. The temperature calculation unit 58 performs the process of step S4 described above. The process determination unit 59 performs the process of step S5 described above. The resetting unit 53 resets the temperature T and the like when it is determined in step S5 that the calculation is to be performed again.

Next, the data of the temperature T obtained by the temperature calculating device 9C is the temperature data storing / outputting device 1 constituted by the data storing device 19a and the data outputting device 19b.
It is output to the outside after passing through 9. Here, the data storage device 19a temporarily stores the temperature data input to the temperature data storage output device 19. The data output device 19b is an output circuit that outputs the temperature data temporarily stored in the data storage device 19a to the outside.

According to the radiation thermometer of the conventional example as described above, the radiation temperature measuring method as described above is configured as an actual radiation thermometer by using the equations (1) to (13). Therefore, it is possible to detect the P-polarized radiance Sp and the S-polarized radiance Ss, and perform the temperature measurement with higher accuracy while correcting the emissivity.

[0052]

However, in the conventional radiation temperature measuring method and radiation thermometer according to the above-mentioned Japanese Patent Laid-Open No. 5-273045, sequential calculation by a large number of processes is performed in the process of obtaining the temperature, as in S1 to S5 described above. Goes in. For this reason, there are problems that the device configuration becomes complicated and the processing content increases.

As another method for measuring the temperature of the surface of the object to be measured by detecting the radiances of the two thermal radiations having different polarization angles, there is JP-A-5-215610. this is,
While performing emissivity correction according to the ratio of the logarithm of the emissivity to the emissivity ratio (εp / εs) [ln (εp)] / ln (εs)], the emissivity εp, or the emissivity εs, A method of more accurately measuring temperature is disclosed. However, this Japanese Patent Laid-Open No. 5-21561
At 0, the installation position of the detector that detects the radiance Sp and the radiance Ss is not taken into consideration, and therefore the measurement error may increase depending on the position of the detector. For example, when such a detector is arranged right above the surface of the object to be measured, the error that the detector has has a great influence on the finally obtained temperature, and There is a problem that the temperature error becomes large.

The present invention has been made in order to solve the above-mentioned conventional problems, and the error in detecting the intensity of the heat radiation light from the surface of the object to be measured is the required surface of the object to be measured. The degree of influence on the temperature is further suppressed, the accuracy of the required temperature is further improved, and consideration is given so that sequential calculation is not performed in the process of obtaining the temperature, thereby simplifying the operation to be performed and the temperature. It is an object of the present invention to provide a radiation temperature measuring method and a radiation thermometer capable of simplifying the configuration of a device (radiation thermometer) for obtaining the temperature.

[0055]

First, the radiation temperature measuring method of the first invention of the present application is as follows. From the thermal radiation light radiated in a specific radiation angle direction from the surface of the temperature-measured object covered with a thin film, The P-polarized radiance and the S-polarized radiance of the specific wavelength component spectrum are detected, and the temperature of the surface of the temperature-measured object is obtained from the P-polarized spectral component radiance and the S-polarized spectral component radiance. In the radiation temperature measuring method, the brewing of the thermal radiation emitted in the direction of the Brewster angle θb of the thin film with respect to the emissivity ratio of the emissivity of the P-polarized spectroscopic component and the emissivity of the S-polarized spectroscopic component. When the relationship of the emissivity regarding the thermal radiation light radiated in the direction of the star angle θb is obtained in advance as the emissivity ratio-emissivity relationship, and the temperature of the surface of the object to be measured is obtained, first,
The P-polarized spectral component radiance and the S-polarized spectral component radiance are detected, and the emissivity ratio is determined based on the detected P-polarized spectral component radiance and S-polarized spectral component radiance. The problem is solved by determining the emissivity from the emissivity ratio-to-emissivity relationship based on the emissivity ratio, and determining the temperature of the surface of the temperature-measuring object based on the emissivity. The present invention provides a radiation temperature measuring method capable of performing the measurement.

On the other hand, in the radiation thermometer of the second invention of the present application, the P-polarized radiation of the specific wavelength component spectrum of the thermal radiation light radiated from the surface of the temperature-measured object covered with the thin film in the direction of the specific radiation angle. The brightness and the radiance of S-polarized light are detected, and P
In a radiation thermometer for determining the temperature of the surface of the object to be measured from the polarization spectral component radiance and the S polarization spectral component radiance, the thermal radiation emitted in the direction of the Brewster angle θb of the thin film. A temperature measuring element for respectively detecting the P-polarized spectral component radiance and the S-polarized spectral component radiance, wherein the area of the light receiving portion is determined according to the allowable range of the radiation angle of the thermal radiation to be detected, A condensing optical unit that condenses the heat radiation light from the surface of the object to be measured to the light receiving unit of the temperature measuring element, and an emissivity ratio of the emissivity of the P-polarized spectral component and the S-polarized spectral component, An emissivity relationship storage device for storing a previously determined emissivity ratio-emissivity relationship, which is a relationship of emissivity related to thermal radiation emitted from the surface of the object to be measured in the direction of the Brewster angle θb, The detected P polarization spectral component radiance and S
An emissivity ratio calculating device for obtaining the emissivity ratio based on the polarization spectral component radiance, and an emissivity is obtained from the emissivity ratio versus the emissivity relationship based on the obtained emissivity ratio. Based on the above, a radiation thermometer that can solve the above problems is provided by including a temperature calculation device that obtains the temperature of the surface of the object to be measured.

[0057]

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

FIG. 1 is a block diagram showing the configuration of a first embodiment of a radiation thermometer to which the first invention and the second invention are applied.

In this embodiment, the heat radiation from the surface of the temperature-measured object 1 is brewed from the surface of the temperature-measured object 1 or, strictly speaking, from the surface of the thin film (metal oxide film) on the surface of the temperature-measured object 1. Specific wavelength λ emitted in the emission angle direction of the star angle θb
By detecting the radiance Sp of the P-polarized thermal radiation of the component spectrum and the radiance Ss of the S-polarized thermal radiation, the temperature of the surface of the temperature-measured object 1 is obtained. The radiation thermometer of this embodiment is composed of a detection device 4A, a temperature calculation device 9A, and the temperature data storage / output device 19. The temperature calculation device 9A includes an emissivity ratio calculation device 12A, a data storage device 13 including an emissivity relation calculation device 14 and an emissivity relation storage device 15, and a temperature calculation device 17.

Hereinafter, while explaining the operation of the present embodiment,
The processing performed by the temperature calculation device 9A described above will also be described.

First, by modifying the equation (9) shown in the description of the conventional example, the following equation can be obtained. This formula is a calculation formula for obtaining the ratio of the emissivity εp for P-polarized light of the specific wavelength λ component spectrum and the emissivity εs for S-polarized light of the specific wavelength λ component spectrum. Further, using this equation, the emissivity ratio arithmetic unit 12A performs an operation for obtaining the emissivity ratio (εp / εs) from the radiances Sp and Ss.

(Εp / εs) = exp [(C2 / λ1) {(1 / Ss)-(1 / Sp)}] (14)

Next, the emissivity ratio (εp / εs) and the emissivity ε
Depending on the object 1 to be measured, there is a certain relationship between p and p, or between the emissivity ratio (εp / εs) and the emissivity εs.
Let these relationships be the emissivity ratio-to-emissivity relationship function f or the emissivity ratio-to-emissivity relationship function g, respectively:
The following equation can be obtained. Here, such a relationship between the function f and the function g can be obtained in advance. In the present embodiment, these functions f and g are obtained in advance by the emissivity relation computing device 14, and the obtained data relating to these functions f and g are stored in the emissivity relation storage device 15 as a data table. ing.

Εp = f (εp / εs) (15) εs = g (εp / εs) (16)

When the temperature T of the surface of the object 1 to be measured is actually obtained, the emissivity ratio (εp / εs) obtained by the emissivity calculating unit 12A based on the equation (14) is used. Then, the emissivity εp is obtained based on the equation (15).
Further, by using the emissivity ratio (εp / εs), the above (16)
The emissivity εs is calculated based on the equation. Furthermore, if the emissivity εp and the emissivity εs are obtained, the temperature T can be obtained according to the Wien's equations such as the equations (7) and (8).

It should be noted that the emissivity εp is calculated by using the above equation (15).
To obtain the emissivity εs using the above equation (16), and further to obtain the temperature T of the surface of the object 1 to be measured based on the Wien's equation using the emissivity εp and the emissivity εs. This is performed by the temperature calculation device 17.
Further, if the temperature T is obtained in this way, the data of the obtained temperature T can be output via the temperature data storage output device 19 described above.

FIG. 2 is a side view showing the structure of the optical system used in the first embodiment.

The structure of the detection device 4A in this embodiment is basically the same as the detection device 4 of the conventional example shown in FIG.
Same as C. In the present embodiment, the temperature measuring element 8
The feature is that the light receiving portion of 5 is made sufficiently small.

Now, consider the optical axis of the condensing optical section 81. This optical axis corresponds to an optical axis that passes at right angles to the center surface of the lens when the condensing optical unit 81 is, for example, a simple optical lens. Here, the distance indicated by the reference numeral A1 and the distance indicated by the reference numeral A2 are different from each other in the distance to the optical axis. Then, the radiation angle θ from the temperature-measured object 1 of the thermal radiation to be detected is different between the portion indicated by the reference numeral A1 and the portion indicated by the reference numeral A2. For example, when the code is A1, the radiation angle is θ1, and when the code is A2, the radiation angle is θ2.

Therefore, in this embodiment, the one corresponding to the temperature measuring element 85 in which the light receiving portion 4a is arranged so as to be at the position of the symbol A1 in FIG. The size of the light receiving area thus reduced is determined according to the allowable range of the radiation angle of the thermal radiation light to be detected. By reducing the size of the light receiving portion in this manner, it is possible to more exactly extract only the thermal radiation light having a desired radiation angle, specifically, the Brewster angle θb, to obtain the radiance.

As described above, in the present embodiment, compared with the conventional example described above with reference to FIGS. 10 and 11, for example, the processing to be sequentially calculated is reduced. In particular, the processing to be executed is taken into consideration in this embodiment so that the processing that is repeatedly executed is further reduced. Further, in the present embodiment, since the detection device 4A is arranged so as to have the Brewster angle θb, it is possible to further improve the temperature measurement accuracy as will be described later in detail with reference to FIGS. 6 and 7 as an example. it can.

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

The second embodiment differs from the first embodiment in the detection device 4B. The first
In the embodiment, the detector 4A having the detectors 4a and 4b for detecting P-polarized light and S-polarized light as shown in FIG. 11 is used. On the other hand, in the second embodiment, the detection device 4B as shown in FIG. 4 uses the condensing optical unit 81 and the temperature measuring element 85 commonly for P-polarized light and S-polarized light. There is.

In FIG. 4, the detection device 4B is
Linear polarization filter main body 80a and 80b, and a linear polarization filter 80B configured with a polarization filter frame 80c to which the linear polarization filter main body 80a and 80b are attached, the condensing optical unit 81, the optical filter 82, the temperature measuring element 85, and the data. It is composed of a sampling circuit 86 and a step motor 73.

In this embodiment, the step motor 73 is used.
By rotating the linear polarization filter 80B, it is possible to set to extract P-polarized light or S-polarized light. Here, the linear polarization filter bodies 80a and 80b are for P polarization or S polarization, respectively.

FIG. 5 is a block diagram showing the configuration of the emissivity ratio computing device 12B used in the second embodiment.

In this embodiment, as described above, one temperature measuring element 85 and the like are used for both P-polarized light and S-polarized light. Therefore, the P-polarized radiance Sp and the S-polarized radiance Ss cannot be detected at the same time. Therefore, in order to store these radiances Sp and Ss, which are sequentially input, in the previous stage of the emissivity ratio calculation device 12A similar to that of the first embodiment, which is built in the emissivity ratio calculation device 12B. The radiance storage device 11 is arranged in the emissivity ratio calculation device 12B.

According to the second embodiment, the P-polarized light and the S-polarized light share the condensing optical section 81, the optical filter 82, the temperature measuring element 85, the data sampling circuit 86 and the like. It is possible to reduce the cost related to these.

In the second embodiment, the linear polarization filter 80B is rotated at a high speed to generate a pulse signal at a position where it becomes P-polarized light or S-polarized light, and the data sample is synchronized with the pulse signal. The fetch timing of the circuit 86 or the fetch timing of the radiance Sp or Ss of the radiance storage device 11 may be set.

[0080]

EXAMPLE Regarding the present embodiment described above, many data were actually obtained for the temperature-measured object 1 shown in Table 1 below.

[0081]

[Table 1]

In Table 1, stainless steel (SUS30
Assuming that the temperature-measured object 1 has an oxide film formed on the surface of the base material of 4), the real part n of the refractive index n and the imaginary part k of the refractive index of the complex index of refraction shown in the equation (5) are calculated. Values are shown. In Table 1, the thermal radiation used for temperature measurement is a specific wavelength component spectrum in which the wavelength λ extracted by the optical filter 82 in FIG. 11 is 1.4 μm.

FIG. 6 is a graph showing the relationship between the emissivity ratio and the emissivity when the Brewster angle θb is set in this embodiment. On the other hand, FIG. 7 shows the Brewster angle θ.
It is a graph which shows the relationship between an emissivity ratio and emissivity when it sets to other than b.

The object to be measured 1 shown in FIGS. 6 and 7
The conditions are as shown in Table 1 above. Further, in FIG. 6, the thermal radiation light radiated from the surface of the temperature-measured object 1 in the radiation angle direction of the Brewster angle θb of the thin oxide film is shown in the detection device 4A or FIG. 3 shown in FIG. Detector 4B
To detect. Specifically, the Brewster angle θb is 6
8 degrees. On the other hand, in FIG. 7, the Brewster angle θ
The radiance of the thermal radiation light radiated in the direction of the radiation angle other than b is detected by the detection device 4A shown in FIG. 1 or the detection device 4B shown in FIG. Specifically, the set angle in FIG. 7 is 10 degrees.

First, paying attention to FIG. 6 for the Brewster angle θb, even when the emissivity ratio (εp / εs) changes from 1.0 to 5.0, the emissivity εp is only about 0.2. Only changed. In comparison, in FIG. 7, which is not the Brewster angle, the emissivity εp is 1. even if the emissivity ratio (εp / εs) changes from about 1.0 to 1.025.
It has changed drastically from 0 to 0.3.

The error of the radiance Sp output from the detector 4A shown in FIG. 1 and the error of the radiance Ss output from the detector 4B shown in FIG.
And the emissivity εs and the emissivity ratio (εp / εs). Here, in the process of detecting the radiances Sp and Ss and finally obtaining the temperature T, the emissivity ratio (εp / ε
When the emissivity εp or εs is obtained from s), the smaller the change in the emissivity εp or the smaller the emissivity εs with respect to the change in the emissivity ratio (εp / εs) caused by the error in the radiance Sp or Ss. The smaller the change, the smaller the error in the emissivity εp obtained by the equation (15) and the error in the emissivity εs obtained by the equation (16), and therefore the error in the temperature T finally obtained.

Considering this, as is clear from the trends in the graphs of FIGS. 6 and 7, it can be seen that the temperature T obtained is more accurate when the Brewster angle θb is set. For example, even when an oxide film gradually grows on the surface of the object 1 to be measured, the temperature can be measured with higher accuracy.

This point is as shown in Table 2 below. In Table 2, the emissivity ratio ER2 obtained under the conditions of FIG. 6 and the temperature measurement error (ΔT / ΔS) for the object 1 to be measured as shown in Table 1 are shown. . Further, the emissivity ratio ER1 obtained under the conditions of FIG. 7 and the temperature measurement error (ΔT / ΔS) corresponding thereto are shown.

[0089]

[Table 2]

In Table 2, for example, when the oxide film thickness is 0.
At 1 μm, (ΔT / ΔS) is 0.889 under the condition of FIG. 3 which is the Brewster angle θb, whereas (ΔT / ΔS) is 137.4 under the condition of FIG. 7, which is the Brewster angle θb. The error is much smaller. That is, the error due to the influence of the detected radiance error on the required temperature T is small.

[0091]

As described above, according to the first invention and the second invention, the temperature of the object to be measured, which is required for the error in detecting the intensity of the heat radiation light from the surface of the object to be measured, is calculated. An operation to be executed by further suppressing the degree of influence on the temperature of the surface, further improving the accuracy of the required temperature, and taking care that a large number of processes are not sequentially calculated in the process of obtaining the temperature. It is possible to obtain the excellent effect that the device can be simplified and the configuration of the device (radiation thermometer) for obtaining the temperature can be simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of a radiation thermometer to which a radiation temperature measuring method of a first invention of the present application and a radiation thermometer of a second invention are applied.

FIG. 2 is a side view showing an optical system used in the first embodiment.

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

FIG. 4 is a block diagram showing a configuration of a detection device used in the second embodiment.

FIG. 5 is a block diagram showing a configuration of an emissivity ratio computing device used in the second embodiment.

FIG. 6 is a graph showing the relationship between the emissivity ratio and the emissivity when the Brewster angle is used in the condition example of the temperature-measuring object.

FIG. 7 is a graph showing a relationship between an emissivity ratio and an emissivity when an angle other than Brewster's angle is set in the condition example of the temperature-measuring object.

FIG. 8 is a side view showing reflection of incident light rays on the surface of the temperature-measured object covered with a thin film.

FIG. 9 is a side view showing reflection of an incident light ray at the Brewster's angle on the surface of the temperature-measured object coated with the thin film.

FIG. 10 is a block diagram showing the configuration of a conventional radiation thermometer.

FIG. 11 is a block diagram showing a configuration of a detection device used in the conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Object to be measured 3 ... Sample 3a ... Thin film 3b ... Base material 4A-4C ... Detection device 4a, 4b ... Detection part 9A-9C ... Temperature calculation device 11 ... Radiation temperature storage device 12A, 12B ... Emissivity ratio calculation device 13, 19a, 55 ... Data storage device 14 ... Emissivity relation calculation device 15 ... Emissivity relation storage device 17 ... Temperature calculation device 19 ... Temperature data storage output device 19b ... Data output device 51 ... Sequential calculation part 52 ... Initial setting part 53 ... Re-setting unit 57 ... Emissivity calculating unit 58 ... Temperature calculating unit 59 ... Processing determining unit 73 ... Step motor 80 ... Linear polarizing filter 80a, 80b ... Linear polarizing filter main body 80c ... Linear polarizing filter mounting frame 81 ... Condensing optics Part 85 ... Temperature measuring element 86 ... Data sampling circuit

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

Claims (2)

[Claims] 1. A radiance of P-polarized light and a radiated brightness of S-polarized light of a specific wavelength component spectrum from among thermal radiated light radiated in a direction of a specific radiation angle from a surface of an object to be measured coated with a thin film. Of the P-polarized spectral component radiance and the S-polarized spectral component radiance to obtain the temperature of the surface of the object to be measured in the radiant temperature measurement method, The relationship of the emissivity of the thermal radiation emitted in the direction of the Brewster angle θb to the emissivity ratio of the P-polarized spectral component and the S-polarized spectral component of the thermal radiation emitted to , The emissivity ratio to the emissivity relationship is obtained in advance. When obtaining the temperature of the surface of the temperature-measured object, first, the P-polarized spectral component radiance and the S-polarized spectral component radiance are detected and detected. It was The emissivity ratio is determined based on the P-polarized spectral component radiance and the S-polarized spectral component radiance, and the emissivity is determined from the emissivity ratio-emissivity relationship based on the determined emissivity ratio. A radiation temperature measuring method, characterized in that the temperature of the surface of the object to be measured is obtained based on the emissivity. 2. A P-polarized radiance and a S-polarized radiance of a specific wavelength component spectrum of thermal radiation emitted from a surface of a temperature-measured object coated with a thin film in a direction of a specific radiation angle are detected. Then, in a radiation thermometer that determines the temperature of the surface of the object to be measured from these P-polarized spectral component radiance and S-polarized spectral component radiance, radiation is performed in the direction of the Brewster angle θb of the thin film. The area of the light receiving portion for detecting the P-polarized spectral component radiance and the S-polarized spectral component radiance of the thermal radiated light is determined according to the allowable range of the radiation angle of the thermal radiated light to be detected. A temperature-measuring element, a condensing optical section for condensing heat radiation light from the surface of the temperature-measuring object to a light-receiving section of the temperature-measuring element, and an emissivity of a P-polarized spectral component and an S-polarized spectral component. The measured temperature against the emissivity ratio An emissivity relationship storage device for storing a previously determined emissivity ratio-emissivity relationship, which is a relationship of emissivity relating to thermal radiation emitted from the body surface in the direction of the Brewster angle θb; An emissivity ratio calculator for obtaining the emissivity ratio based on the P-polarized spectral component radiance and the S-polarized spectral component radiance, and the emissivity ratio-to-emissivity relationship based on the obtained emissivity ratio. And a temperature calculator for calculating the temperature of the surface of the object to be measured based on the emissivity.