JP2021135105A - Radiation temperature measurement device using multireflection between mirrors - Google Patents

Abstract

To provide a radiation temperature measurement device that enlarges nominal emissivity by multireflection between mirrors when an inclination mirror cannot be installed above a measurement sample.SOLUTION: A radiation temperature measurement device and the like are provided that have a radiation thermometer for measuring radiance having nominal emissivity of the measurement sample enlarged by multi-reflected light between one or more type 1 mirrors configured to reflect light to be radiated from the measurement sample at an angle θ of a prescribed range with respect to a measurement surface normal of a measurement sample to be arranged in an arrangement part, cause the reflected light to be incident upon the measurement sample again, and cause the light to be radiated at an angle -θ of the prescribed range with respect to the measurement surface normal of the measurement sample from an incidence point, and one or more type 2 mirrors configured to reflect light to be radiated from the measurement sample at the angle -θ of the prescribed range with respect to the measurement surface normal of the measurement sample to be arranged in the arrangement part, cause the light to be incident upon the measurement sample again, and cause the light to be radiated at the angle θ of the prescribed range with respect to the measurement surface normal of the measurement sample from the incidence point.SELECTED DRAWING: Figure 1

Description

In the present invention, the apparent emissivity of the measurement sample is increased by receiving the reflected light from the mirror by using a mirror for reflecting the light emitted from the measurement sample and making it incident on the measurement sample again. , Regarding a radiation thermometer that measures temperature.

A non-contact radiation thermometer that does not damage the surface of the metal material is widely used for measuring the surface temperature of the metal material in the manufacturing process of the metal material such as rolling and continuous annealing. The radiation thermometer measures the intensity of thermal radiation from the object (radiance) and converts the intensity of thermal radiation into temperature based on the relationship between the thermal radiation intensity of the blackbody and the temperature. When the emissivity of the substance to be measured for temperature is different from the emissivity of the black body, the temperature can be obtained by correction according to the emissivity of the substance. However, the properties of the metal surface of the steel sheet during the rolling process fluctuate due to the oxide film on the metal surface generated by heating and cooling, and the emissivity also fluctuates accordingly, so it is not possible to make corrections according to the emissivity. Accurate temperature measurement was difficult.

Therefore, by arranging the reflector at an angle with respect to the measurement target such as a steel plate and multiple-reflecting the radiated light from the steel plate between the reflector and the surface of the steel plate, the apparent emissivity of the surface of the steel plate is increased and a blackbody is formed. A temperature measurement method has been proposed in which the emissivity of a blackbody radiation is regarded as blackbody radiation and the temperature is converted by approaching the emissivity of (Patent Document 1).

JP-A-59-87329

In the temperature measurement method of Patent Document 1, the reflector must be arranged so as to face the steel plate, and in a measurement environment where there is no room for the reflector to be arranged in the space directly above the steel plate, such a temperature measurement method is used. There was a problem that it could not be applied.

Therefore, in order to solve the above problems, in the present invention, at least the measurement surface has a predetermined range with respect to the arrangement portion for arranging the flat measurement sample and the measurement surface normal line of the measurement sample arranged in the arrangement portion. The first configuration is such that the light emitted from the measurement sample at an angle θ is reflected and incident on the measurement sample again, and is emitted from the incident point at an angle −θ within a predetermined range with respect to the measurement surface normal line of the measurement sample. The light emitted from the measurement sample is reflected at an angle −θ within a predetermined range with respect to the mirror of the seed and the measurement surface normal line of the measurement sample placed in the arrangement portion, and is incident on the measurement sample again, and is measured from the incident point. It consists of a second-class mirror configured to radiate at an angle θ within a predetermined range with respect to the measurement surface normal of the sample, and the first-class mirror and the second-class mirror are each one or more. Provided is a radiation temperature measuring device including a radiation thermometer for measuring radiation brightness in which the apparent radiation coefficient of a measurement sample is increased by light multiple reflected between the plurality of mirrors.

Further, in the above-mentioned radiation temperature measuring device, the radiation thermometer is arranged behind a first-class mirror and / and a second-class mirror, and multiple reflections are made from a hole provided in the mirror in front of the radiation thermometer. Provided is a radiation thermometer configured to capture light.

Further, in any of the above radiation temperature measuring devices, there is provided a radiation temperature measuring device in which a polarizing portion having a p-polarizer is provided in front of the light intake surface of the radiation thermometer.

Further, in any of the above radiation temperature measuring devices, a radiation temperature measuring device having a value of θ of 60 degrees or more is provided.

Further, in any of the above radiation temperature measuring devices, a chamber provided with an internal observation window is provided, and the arrangement portion is arranged in the chamber, and is a first-class mirror, a second-class mirror, and a radiation thermometer. The light intake surface of the above provides a radiation thermometer which is arranged outside the chamber and is configured to allow light from a measurement sample to enter through an internal observation window.

Further, in any of the above-mentioned radiation temperature measuring devices, the arrangement unit provides a radiation temperature measuring device having a moving means for moving the measurement sample on the arrangement unit.

Further, at least the measurement surface has an arrangement portion for arranging a flat measurement sample and light emitted from the measurement sample at an angle θ within a predetermined range with respect to the measurement surface normal line of the measurement sample arranged in the arrangement portion. It is arranged in a first-class mirror configured to reflect and re-enter the measurement sample and radiate from the incident point to the measurement surface normal line of the measurement sample at an angle −θ in a predetermined range, and an arrangement portion. The light emitted from the measurement sample is reflected at an angle −θ of a predetermined range with respect to the measurement surface normal line of the measurement sample and is incident on the measurement sample again, and the predetermined range from the incident point with respect to the measurement surface normal line of the measurement sample. It consists of a second-class mirror and a radiation thermometer that are configured to radiate at an angle of θ, and each of the first-class mirror and the second-class mirror is composed of one or more mirrors. It is a temperature measurement method of the radiation temperature measuring device, and emits radiation brightness in which the apparent radiation coefficient of the measurement sample is increased by the arrangement step of arranging the measurement sample in the arrangement portion and the light multiple reflected between the plurality of mirrors. Provided is a temperature measuring method including a measuring step for measuring with a thermometer.

Further, at least the measurement surface has an arrangement portion for arranging a flat measurement sample and light emitted from the measurement sample at an angle θ within a predetermined range with respect to the measurement surface normal line of the measurement sample arranged in the arrangement portion. It is arranged in a first-class mirror configured to reflect and re-enter the measurement sample and radiate from the incident point to the measurement surface normal line of the measurement sample at an angle −θ in a predetermined range, and an arrangement portion. The light emitted from the measurement sample is reflected at an angle −θ of a predetermined range with respect to the measurement surface normal line of the measurement sample and is incident on the measurement sample again, and the predetermined range from the incident point with respect to the measurement surface normal line of the measurement sample. It consists of a second-class mirror that is configured to radiate at an angle θ of, and the first-class mirror and the second-class mirror are arranged and configured in a regular N-side shape from N mirrors, respectively. The value of N is 3 or more and infinity or less, and the radiation having a radiation thermometer for measuring the radiation brightness in which the apparent radiation coefficient of the measurement sample is increased by the light multiple reflected between the plurality of mirrors. Provide a temperature measuring device.

According to the present invention, even when there is no margin in the space above the measurement surface of the measurement sample, the apparent emissivity can be increased by multiple reflections, and the accuracy of temperature measurement can be improved.

In addition, the number of multiple reflections between the measurement sample and the mirror surface can be increased as compared with the case of using a tilted mirror. Further, by using a plurality of mirrors, the degree of freedom in the layout of temperature measurement is high, and the layout can be easily set or changed.

Conceptual diagram showing an example of the radiation temperature measuring device of the first embodiment _{The figure which plotted the change of the apparent emissivity ε eff} based on the equation 6 with the sample emissivity and the number of reflections as parameters respectively. A table showing changes in the apparent emissivity ε _{eff shown in FIG.} Conceptual diagram showing another example of the radiation temperature measuring device of the first embodiment. Conceptual diagram showing a generalized mode of radiation temperature measurement using multiple reflections Conceptual diagram showing an example of a radiation temperature measuring device using a plane mirror for a first-class mirror and a second-class mirror. Conceptual diagram showing an example of a radiation temperature measuring device using a cylindrical mirror (cylindrical surface mirror) for a first-class mirror and a second-class mirror. Conceptual diagram showing an example of a radiation temperature measuring device using a first-class mirror and a second-class mirror with a right-angled mirror. Conceptual diagram showing an example of a radiation temperature measuring device in which a ring-shaped mirror is composed of a first-class mirror and a second-class mirror. A flow chart showing an example of the flow of the temperature measuring method of the radiation temperature measuring device of the first embodiment. Conceptual diagram showing an example of the radiation temperature measuring device of the second embodiment The figure which shows the reflection distribution measurement result in the range of ± 10 degrees for every incident angle θ using a semiconductor laser for a Si wafer. Experimental or simulation results of polarization direction emissivity in the polarization direction of various samples Conceptual diagram showing an example of applying a radiation temperature measuring device to a heating device

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The present invention should not be limited to these embodiments, and may be implemented in various embodiments without departing from the gist thereof.

In the first embodiment, claims 1, 2, and 6-8 will be mainly described. In the second embodiment, claims 3 and 4 will be mainly described. In the third embodiment, claim 5 will be mainly described.
<Embodiment 1>
<Outline of Embodiment 1>

The radiation temperature measuring device of the present embodiment is a spherical type capable of reflecting light emitted at an angle θ and an angle −θ with respect to the measurement surface normal line of the measurement sample with the measurement sample sandwiched therein. Using a first-class mirror and a second-class spherical mirror, the emitted light is multiple-reflected on each mirror and the measurement surface of the measurement sample, and the incident optical axis of the radiation thermometer on one mirror surface. A hole is provided at the intersection with the hole, and the light incident through the hole is taken into a radiation thermometer to measure the temperature. With this configuration, it is possible to measure the radiance in which the apparent emissivity is increased by multiple reflections.
<Embodiment 1 Configuration>

FIG. 1 is a conceptual diagram showing an example of the radiation temperature measuring device of the present embodiment. FIG. 1 (a) is a view viewed from above, and FIG. 1 (b) is a view viewed from the side. The radiation temperature measuring device of the present embodiment includes an arrangement unit 0106 for arranging the measurement sample 0101, a first-class mirror 0102, a second-class mirror 0103, and a radiation thermometer 0105.
<Example 1 Measurement sample>

First, the measurement sample 0101 has at least a flat measurement surface (measurement points are included in the measurement surface). That is, the measurement by the radiation thermometer described later is performed by focusing the focus of the radiation thermometer on the flat region of the measurement sample. Further, the measurement sample is various such as a steel plate, a semiconductor wafer, and aluminum. Further, as a scene where the temperature is measured, the temperature is measured in various processes requiring temperature control such as a rolling process of steel or aluminum, a lamp annealing of a silicon wafer, a continuous casting process, and a painting process of a car body. Note that FIG. 1 shows a steel sheet in the rolling process as a measurement sample. Further, if there is a spot having a normal direction in the same direction as the reference surface such as the arrangement portion, the measurement surface does not necessarily have to be flat.
<Embodiment 1 Arrangement Unit>

As shown in FIG. 1 (b), the arrangement unit 0106 is for arranging the measurement sample 0101. The measurement sample may be arranged by the arrangement portion by fixing the measurement sample, or by providing a moving means such as a roller conveyor so that the measurement sample can be moved on the arrangement portion. It may be arranged while moving.
<Embodiment 1 Radiation Thermometer>

The radiation thermometer 0105 measures the radiance in which the apparent emissivity of the measurement sample is increased by the light multiplely reflected between the first-class mirror and the second-class mirror. The radiation thermometer is composed of an infrared light detection element such as a thermopile and an optical system such as a lens that collects infrared light emitted from an object onto the infrared light detection element.
<Embodiment 1 Type 1 Mirror>

As shown in FIG. 1A, the first-class mirror 0102 is a spherical mirror, and is arranged so that the points P on the measurement surface substantially coincide with each other as the focusing points of the mirrors. Further, the first-class mirror is provided with a hole portion 0107 at substantially the center of the reflecting surface thereof.

As shown in FIG. 1 (b), the first-class mirror 0102 reflects light emitted at an angle θ from the point P on the measurement surface with respect to the measurement surface normal 0104, and is made to enter the measurement sample again. It is configured to radiate from the incident point at an angle −θ with respect to the measurement surface normal.

When the shape of the reflecting surface of the first-class mirror is a spherical surface with a radius R, the distance between the center of the first-class mirror and the point P on the measurement surface is the same as the radius R. A first-class mirror is placed on the measurement sample.

Then, in the first-class mirror, the light emitted from the condensing point P on the measurement surface with respect to the measurement surface normal line 0104 at an angle θ passes through the hole portion 0107 and is incident on the radiation thermometer 0105. The light emitted from the condensing point P that has reached the mirror surface without passing through the hole is reflected back toward the condensing point P.

Then, the radiation thermometer 0105 is arranged behind the first-class mirror, is configured to take in the light multiplely reflected from the hole 0107 provided in front of itself, and its light receiving axis is set at the focusing point P. It is arranged to face and is focused on the focusing point P.

Further, the reflectance of the first-class mirror is preferably high, and the reflectance ρ is preferably 0.95 or more. This is because the higher the reflectance of the first-class mirror, the higher the apparent emissivity can be. This also applies to the second type of mirror.
<Embodiment 1 Type 2 Mirror>

The second type mirror 0103 reflects the light radiated from the measurement sample at an angle −θ within a predetermined range with respect to the measurement surface normal line of the measurement sample arranged in the arrangement portion, and is incident on the measurement sample again. It is configured to radiate from a point at an angle θ within a predetermined range with respect to the measurement surface normal line of the measurement sample.

Further, the second type mirror is a spherical mirror in which the shape of the reflecting surface is a spherical surface having a radius R like the first type mirror, and the center of the second type mirror and the point P of the measurement surface The price is assigned to the measurement sample so that the distance is the same as the radius R.
<Embodiment 1 Measurement Principle>

In the above configuration, the multiple reflections generated between the first-class mirror and the second-class mirror, and the principle of increasing the apparent emissivity of the measurement sample to measure the temperature will be described below.

Since the first-class mirror is a spherical mirror having a radius R and its focal length is f = R / 2, the optical focusing formula shown by the following mathematical formula 1 holds.

Assuming that the distance between the point P of the measurement sample and the spherical mirror is a = R, equations 1 to b = R. That is, the radiant flux emitted from the point P of the measurement sample by the spherical first-class mirror is reflected by the mirror surface and returns to the point P again (the same applies to the second-class mirror). Then, the first-class mirror and the second-class mirror face each other at an angle θ that is a mirror surface target with respect to the measurement surface normal of the measurement sample. Therefore, the radiant flux proceeds to a point P, a first-class mirror, a point P, a second-class mirror, a point P, and so on, and is reflected multiple times at both mirrors and the point P.

Here, now cities specimen sample theta direction of the (spectral) emissivity epsilon _theta, when the measurement sample surface that it completely specularly reflecting surface, permanently repeated multiple reflections between the two mirrors. However, in reality, it converges to a finite number of reflections due to absorption on the sample surface and the influence of the reflectance of the spherical mirror. Therefore, the amount of the radiant flux φ that comes out of the hole when reflected by the first-class mirror is proportional to the following formula 2 when the integration between the mirrors is regarded as a finite number of n round trips.

The radiation thermometer detects Equation 3 as the _{apparent spectral radiance L eff} of the radiant flux corresponding to the radiant flux φ of Equation 2.

Here, ρ is the reflectance of the first-class mirror and the second-class mirror, and L _{b and λ} (T) are the blackbody spectral radiances of the temperature T and the wavelength λ. The apparent spectral radiance L _eff of Equation 3 can be transformed into Equation 5 below if the parameter α is taken as Equation 4 below.

Therefore, the apparent spectral emissivity ε _eff is given by Equation 6.

ちなみにρ＝０．９５のとき、数式４よりα＝０．０５３となる。 Here, when n → ∞, ρ (1-ε _θ ) <1, so ρ ^{n + 1} (1- ^{ε θ) n + 1} → 0, and Equation 5 can be expressed by Equation 7. This equation represents the ultimate apparent radiance when the measurement sample is a perfectly mirror-reflecting surface.

By the way, when ρ = 0.95, α = 0.053 from the mathematical formula 4.

_{FIG. 2 is a plot of changes in the apparent emissivity ε eff} based on Equation 6 with the number of reciprocating reflections n and the emissivity ε _θ of the measurement sample as parameters. In FIG. 2A, the horizontal axis represents the sample emissivity ε _λ , and in FIG. 2B, the horizontal axis represents the number of reflections n. The reflectance ρ of the first-class mirror and the second-class mirror was ρ = 0.95. Further, FIG. 3 shows the changes in _{the apparent emissivity ε eff shown in FIG. 2 in a table.}

As shown in FIGS. 2 and 3, if the original sample emissivity is 0.6, the apparent emissivity is 0.95 or more even if the number of reflections is n = 5. If the apparent emissivity is as high as this, it can be regarded as blackbody radiation, and even if the emissivity of the actual sample is unknown and fluctuating, it can be regarded as blackbody radiation and the temperature can be measured. ..
<Embodiment 1 Other Aspects>

So far, we have shown a radiation temperature measuring device in which a first-class mirror and a second-class mirror are each composed of a spherical mirror, and the radiance of a measurement sample is measured through a hole provided in the first-class mirror. rice field. In the following, various other aspects of the radiation temperature measuring device will be shown. In any of the embodiments, as in the above-described embodiment, the components for arranging the measurement sample, the first-class mirror emitted from the measurement sample, the second-class mirror, and the radiation thermometer are provided. It has different forms such as a first-class mirror and a second-class mirror.
<Multiple reflection by a mirror without holes>

In the radiation thermometer shown in FIG. 1, the first-class mirror and the second-class mirror are spherical mirrors, and a hole is provided in one of the mirrors to radiate a radiant flux that is repeatedly reflected. It was configured so that the thermometer could measure it. With such a configuration, there is an advantage that the installation space can be made compact because the temperature can be measured with the minimum number of mirrors.

In the following embodiment, the temperature can be measured by increasing the apparent emissivity by multiple reflection without using a spherical mirror having a hole, which requires relatively high processing accuracy. FIG. 4 shows an aspect of a basic radiation temperature measuring device using a mirror having no hole.

FIG. 4 is a conceptual diagram showing an example of a radiation temperature measuring device that utilizes multiple reflections by a plurality of mirrors. FIG. 4A is a view viewed from above, and FIG. 4B is a view viewed from the side. The radiation temperature measuring device of the present embodiment is composed of an arrangement unit 0406 for arranging the measurement sample 0401, a first-class mirror 0402, two second-class mirrors 0403 and 0404, and a radiation thermometer 0405. Become. The arrows shown between the first type mirror, the second type mirror, the points P ₁ , P ₂ , P _{3 on} the measurement surface of the measurement sample, and the radiation thermometer are the radiation temperature from _{the point P 3.} It shows the path of light that can enter the meter.

4 (a) and as shown in FIG. 4 (b), the mirror 0402 of the first species, again reflecting the light emitted at an angle θ with respect to the measurement surface normal from a point P ₁ of the measuring surface It is configured to be incident on a point P ₂ of the measurement surface. On the contrary, it is configured so that the _{light radiated from the measurement surface point P 2} at an angle θ with respect to the measurement surface normal can be reflected and made to _{enter the measurement surface point P 1 again.}

The mirror 0403 of the second kind reflects the light emitted at the angle -θ is configured to be incident on a point P ₃ of the measurement surface again to the measuring surface normal from the point P ₂ of the measuring surface ing. Also configured to be able to enter the point P ₂ of the measurement surface again reflects light emitted at an angle -θ with respect to the measurement surface normal from the point P ₃ of the measurement surface reversed. The second kind of mirror 0404 for reflecting the light emitted from the point P ₁ is directly opposite the point P _1, configured to be able to enter the P ₁ reflects the light emitted from P ₁ Has been done. Such a second type mirror is called a retroreflective mirror.

Also in this example, a spherical mirror having a concave spherical surface as a reflecting surface is used as the first type mirror, and the reflectance of the mirror is preferably high, and the reflectance ρ is preferably 0.95 or more. ..

The radiation thermometer 0405 exists at a position where the radiation thermometer 0405 is focused obliquely with respect to the measurement surface. Therefore, in order to sufficiently receive the light emitted from the measurement surface, it is desirable to configure the optical system of the radiation thermometer so that the depth of field and the depth of focus are increased. This is because the amount of light received from the measurement surface and the intensity of light received from the measurement surface can be increased by making the area of focus wide on the measurement surface, which contributes to increasing the radiance. For example, the depth of field is preferably 20 to 30 cm, and the depth of focus is preferably about 2 to 3 cm. With this configuration, a region having a diameter of about 3 cm can be focused.

Subsequently, the multiple reflection in this embodiment will be described. As shown in FIG. 4A, the light received by the radiation thermometer is considered to be the sum of the following six lights. First of all, it is the light received directly from the point P _3. Then, incident on point P ₃ is reflected by the mirror 0403 of the second type generated from the point P _2, a light reaching the radiation thermometer is reflected at point P _3. Then, incident on point P ₂ is reflected by the first type of mirror 0402 is emitted from the point P _1, incident on point P ₃ after reflected at a point P ₂ is reflected by the second kind of mirror 0403, a light reaching the radiation thermometer is reflected at point P _3. So far, there are three lights. In this specification, multiple reflections that take such a path are referred to as forward multiple reflections.

Further, a light emitted from each point of P _{1, P 2,} P _3, even light that has passed through the reflection by the second kind of mirror 0404 directly facing the point P ₁ is incident on the radiation thermometer. For example, from the point P _1, not only the direction in which the mirror 0402 of the first kind are located, light is emitted in a direction in which the mirror 0404 of the second type is located. Light emitted in the second kind of mirror 0404 from the point P ₁ is reflected is incident at a point P ₁ again. The light incident on the point P ₁ is reflected at point P _1, and reflects incident on the first kind of mirror 0402. Thereafter, the point _{P 2,} the second kind of mirror 0403, through, eventually entering from point _{P 3} to the radiation thermometer. Likewise, it emitted from the point P ₂ and the point P _3, via the reflection by the mirror 0404 of the second kind to reach a radiation thermometer. These are three more lights. In addition, the multiple reflection which takes such a path is referred to as a multiple reflection including a reverse direction in this specification.

As described above, the light received by the radiation thermometer is the sum of the above-mentioned six lights. Next, consider the spectral radiance of each of these six lights. Spectral radiation brightness of black body at temperature T at angle θ direction at temperature T of _{measurement surface, radiation coefficient ε θ} in the angle θ direction of the measurement sample, reflectance ρ of the first type mirror and second type mirror, wavelength λ the L _b, when the _lambda (T), emitted from the point P _3, the spectral radiance of the light entering the direct radiation _thermometer, ε θ _L b, the _lambda (T).

Also, emitted from the point P _2, is reflected by the mirror 0403 of the two entering the P _3, the spectral radiance of the light entering the radiation thermometer is reflected at P ₃ is, ρ (1-ε _θ ) ε _θ L _{b, λ} (T). Here, (1-ε _θ ) is the reflectance of the measurement sample in the angle θ direction from Kirchhoff's law and energy conservation law. The measurement sample is considered to be a non-permeable material.

Thus, the light emitted from the point P _2, and the reflection by the sample and the reflection by the first kind of mirror through once respectively incident on the radiation thermometer. Therefore, the spectral radiance of the light is spectral radiance of the light emitted from the P ₂ ε θ _{L b,} and the reflectivity of the first kind of mirror _lambda (T) [rho, the reflectance of the measurement sample (1 Multiplyed by ε _θ ), it becomes ρ (1-ε _θ ) ε _θ L _{b, λ} (T).

And the sum of the six lights can be shown as follows.
ε _θ {1 + ρ (1-ε _θ ) + ρ ² (1-ε _θ ) ² + ... + ρ ⁵ (1-ε _θ ) ⁵ } L _{b, λ} (T)

Further, FIG. 5 is a conceptual diagram showing a generalized mode of radiation temperature measurement using the multiple reflections as described above. As shown, the light emitted from the measurement surface by the plurality of first-class mirrors 0502 and the plurality of second-class mirrors 0503 (including one retroreflective second-class mirror 0504) reflects. Repeatedly, it is incident on the radiation thermometer 0505 from the point "P _{n". The spectral radiance L eff} of the light incident on the radiation thermometer can be expressed by the following mathematical formula 8.

This formula 8 is the same as the formula 3 already described. Then, also in this embodiment, as described above, if n → ∞ and the measurement sample is a perfect mirror reflection surface, the apparent radiance is as shown by Equation 7. Therefore, even in the radiation temperature measuring device in this embodiment, the temperature can be measured by increasing the apparent emissivity.
<Multiple reflection by flat mirror>

FIG. 6 is a conceptual diagram showing an example of a radiation temperature measuring device using a plane mirror for a first-class mirror and a second-class mirror. As shown in FIG. 6B, the first-class mirror 0601 is arranged so that the mirror surface faces the measurement surface normal 0603 of the measurement target 0602 at an angle θ, and the second-class mirror 0604 , The mirror surface is arranged so as to face the measurement surface normal at an angle −θ.

As shown in FIG. 6 (a), the radiation thermometer 0605 focused on a point P ₅ of the measuring surface is oriented light receiving axis of the mirror surface normal direction of the second type mirror facing the direction of the angle φ It is arranged like this. Further, the one end of the second kind of mirror 0604, an angle from the main mirror surface normal direction of the mirror reflecting surface of the second kind to be incident again point P ₁ the light incident from the point P ₁ of the measuring surface It is equipped with a φ-tilted retroreflective mirror 0606.

With the above configuration, the light emitted from the measurement surface is multiple-reflected between the first-class mirror and the second-class mirror, and the apparent emissivity of the light incident on the radiation thermometer due to the multiple reflection is determined. Can be made larger.
<Multiple reflection by cylindrical mirror>

FIG. 7 is a conceptual diagram showing an example of a radiation temperature measuring device using a cylindrical mirror (cylindrical surface mirror) for a first-class mirror and a second-class mirror. As shown in FIG. 7B, the first-class mirror 0701 is arranged so that the mirror surface faces the measurement surface normal 0703 of the measurement target 0702 at an angle θ, and the second-class mirror 0704 , The mirror surface is arranged so as to face the measurement surface normal at an angle −θ.

As shown in FIG. 7 (a), the radiation thermometer 0705 focused on a point P ₅ of the measuring surface is oriented light receiving axis of the mirror surface normal direction of the second type mirror facing the direction of the angle φ It is arranged like this. Further, the one end of the second kind of mirror, the angle from the primary mirror surface normal direction of the mirror reflecting surface of the second kind to be incident again point P ₁ the light incident from the point P ₁ of the measurement surface φ A tilted retroreflective mirror 0706 is provided.

With the above configuration, the light emitted from the measurement surface is multiple-reflected between the first-class mirror and the second-class mirror, and the apparent emissivity of the light incident on the radiation thermometer due to the multiple reflection is determined. Can be enhanced.
<Multiple reflection by right angle mirror>

FIG. 8 is a conceptual diagram showing an example of a radiation temperature measuring device using a first-class mirror and a second-class mirror with a right-angled mirror. As shown in FIG. 8B, the first-class mirror 0801 is arranged so that the mirror surface faces the measurement surface normal 0803 of the measurement target 0802 at an angle θ, and the second-class mirror 0804 , The mirror surface is arranged so as to face the measurement surface normal at an angle −θ.

As shown in FIG. 8A, the first-class mirror and the second-class mirror are arranged so that their mirror surfaces facing each other are shifted parallel to each other in the y-axis direction in the drawing. Further, the one end of the second kind of mirror, retroreflective portion 0806 reflective surface directly facing the point P ₁ to be incident again point P ₁ the light incident from the point P ₁ of the measurement surface facilities. Further, by shifting as described above, the light radiated from the other end of the second type mirror via multiple reflections between the mirror surfaces does not interfere with the opposite first type mirror and the radiation temperature. It is configured to be incident on a total of 0805.

With the above configuration, the light emitted from the measurement surface is multiple-reflected between the first-class mirror and the second-class mirror, and the apparent emissivity of the light incident on the radiation thermometer due to the multiple reflection is determined. Can be enhanced. Even if the right-angled mirror is replaced with a right-angled prism, the same effect can be obtained.
<Multiple reflection by ring-shaped mirror>

This aspect is based on the above-mentioned radiation temperature measuring device, and is characterized by the arrangement of a first-class mirror and a second-class mirror. That is, the first-class mirror and the second-class mirror in this embodiment are each arranged and configured in a regular N-sided shape from N mirrors, and the value of N is 3 or more and infinity or less.

FIG. 9 is an example showing a case where the value of N is infinite. As shown in FIG. 9A, where the first-class mirror and the second-class mirror are arranged in a regular N-sided shape, by setting the value of N to infinity, one ring is eventually formed. The shape mirror 0901 constitutes.

The ring-shaped mirror reflects the light emitted from the measurement sample at an angle θ (angle −θ) with respect to the measurement surface normal line 0906 of the measurement sample and makes it incident on the measurement sample again, and the measurement surface of the measurement sample is reflected from the incident point. It is configured to radiate at an angle −θ (angle θ) within a predetermined range with respect to the normal line. Then, the radiation thermometer 0903 is arranged so as to receive the light radiated from the point P slightly deviated from the center of the ring-shaped mirror at an angle θ with respect to the measurement surface normal through the hole portion 0902. With such a configuration, the radiation thermometer can measure the radiance with an increased apparent emissivity by multiple reflections between the ring-shaped mirror and the region centered on the point P on the measurement surface.
<Embodiment 1 Temperature measurement method>

The invention relating to the radiation temperature measuring device of the present embodiment described above can also be expressed as an invention relating to a temperature measuring method. That is, it is composed of the above-mentioned arrangement part, the first-class mirror, the second-class mirror, and the radiation thermometer, and the first-class mirror and the second-class mirror are each composed of one or more mirrors. It can be expressed as a temperature measuring method of a thermometer.

FIG. 10 is a flow chart showing an example of the flow of the temperature measuring method of the radiation temperature measuring device of the present embodiment. As shown in the figure, first, the measurement sample is placed in the placement section (1001 placement step). Then, the radiance in which the apparent emissivity of the measurement sample is increased by the light multiplely reflected between the plurality of mirrors is measured with a radiation thermometer (1002 measurement step).
<Effect of Embodiment 1>

With the radiation temperature measuring device of the present embodiment, even when there is no room above the measurement surface of the measurement sample, the apparent emissivity can be increased by multiple reflections, and the emissivity is unknown and variable. It is possible to measure the temperature of the object with high accuracy.
<Embodiment 2>
<Outline of Embodiment 2>

This embodiment is based on the first embodiment, and the apparent emissivity is increased by receiving p-polarized light, and the above-mentioned range of the angle θ is specified as a range showing more specular reflection characteristics. It increases the emissivity.
<Embodiment 2 Configuration>

FIG. 11 is a conceptual diagram showing an example of the radiation temperature measuring device of the present embodiment. This radiation temperature measuring device has the same basic configuration as the radiation temperature measuring device shown in FIG. 1 in the first embodiment, and further provides a polarizing portion having a p-polarizer in front of the radiation thermometer.

As shown in FIG. 11A, the first-class mirror 1102 and the second-class mirror 1103 are spherical mirrors, respectively, and their respective focusing points substantially coincide with each other at the point P on the measurement surface of the measurement sample 1101. It is arranged like this. Further, the first-class mirror is provided with a hole 1107 at substantially the center of the reflecting surface thereof. A polarizing unit 1108 having a p-polarizer is provided behind the first-class mirror and in front of the light capture surface of the radiation thermometer 1105.

Further, as shown in FIG. 11B, in the first-class mirror 1102, light radiated from a point P on the measurement surface at an angle θ with respect to the measurement surface normal passes through the hole 1107 and radiates. It is configured to be incident on the thermometer 1105 and to reflect the light emitted from the point P, which has reached the mirror surface without passing through the hole, toward the point P again. Further, the second type mirror 1103 is configured to reflect the light radiated from the point P on the measurement surface at an angle −θ with respect to the normal of the measurement surface and to enter the point P again. ..
<Embodiment 2 Angle θ>

In the present embodiment, the angle θ is limited to 60 degrees or more. More preferably, it is limited to 70 degrees or higher. As described in the first embodiment, a large number of reflections n in multiple reflections contributes to increasing the apparent emissivity. Therefore, it is preferable that the measurement sample has a mirror-like reflection characteristic. In other words, it can be said that it is preferable that the measurement sample has a reflection characteristic with little diffuse reflection.

FIG. 12 shows reflection of a Si wafer (roughness Ra = 0.28 μm) in a range of ± 10 degrees for each incident angle θ (30 to 80 degrees) using a semiconductor laser (λ = 532 nm, unpolarized light). This is the distribution measurement result. Where the incident angle θ is small, the reflection distribution has a diffuse spread, but when θ = 70 degrees or more, the diffuse distribution of the reflection is remarkably reduced, showing mirror reflection characteristics, and the number of reflections n can be increased. It can greatly contribute to enhancing the effect in the present invention of increasing the apparent emissivity by multiple reflections. In addition, a synergistic effect can be achieved in relation to the polarization characteristics shown below.
<Action 2 by p-polarizer>

FIG. 13 shows the results of experiments or simulations of the emissivity of the polarization direction in the polarization direction of various samples ((a) Si wafer, (b) aluminum, (c) cold-rolled steel sheet, (d) stainless steel sheet) (the following documents). Was referred to). The emissivity and reflectance of Si wafers and various metals vary greatly depending on the polarization. In both cases, the p-polarized emissivity increases (the p-polarized reflectance decreases) in the direction of θ = 70 to 80 degrees. On the contrary, the s-polarized emissivity decreases (the s-polarized reflectance increases). Therefore, in this method, the emissivity increases if p-polarized light is used in the direction of θ = 70 to 80 degrees, so that the effect of the present invention can be further enhanced (References Toru Inuchi, Ishii, Polarized Brightness). Radiation temperature measurement method for bright metals near room temperature, Proceedings of the Society of Instrument and Control Engineers, 36, 395/401 (2000)).

The action and effect of setting the angle θ to 60 degrees or more and the action and effect of providing the polarizing portion also occur in the various radiation temperature measuring devices shown in the first embodiment.
<Effect of Embodiment 2>

According to the radiation temperature measuring device of the present embodiment, the apparent emissivity can be further increased, and the temperature can be accurately measured even for a variable object whose emissivity is unknown.
<Embodiment 3>
<Outline of Embodiment 3>

The radiant temperature measuring device of the present embodiment is a radiant temperature measuring device for measuring the temperature of a measurement sample arranged in a chamber provided with heating means based on the first or second embodiment.
<Structure 3 of Embodiment>

FIG. 14 is a conceptual diagram showing an example in which the radiation temperature measuring device of the present embodiment is applied to a heating device. As shown in the figure, the chamber 1401 is provided with a heating means 1403 for heating the measurement sample 1402 such as a silicon wafer from below, and an internal observation window 1404. The above-mentioned arrangement portion 1405 is arranged in the chamber. For the internal observation window, calcium fluoride, synthetic quartz, germanium, magnesium fluoride potassium bromide, sapphire, silicon, sodium chloride, zinc selenium, zinc sulfide, etc., which transmit infrared light, can be used.

The light intake surface of the first-class mirror 1406 and the second-class mirror 1407, and the radiation thermometer 1408 are arranged outside the chamber so that the light from the measurement sample is incident through the internal observation window. Has been done. In the example of this figure, both the first-class mirror and the second-class mirror are spherical mirrors, and the first-class mirror is provided with the above-mentioned hole and is behind the first-class mirror. The radiation thermometer located in is configured to receive light that has passed through the hole.

By configuring the radiation thermometer in this way, the light radiated from the measurement sample subjected to heat treatment in the chamber can be combined with the first-class mirror and the second-class mirror through the internal observation window. Multiple reflections and multiple reflections of light enter the radiation thermometer, and as described in the first embodiment, the apparent emissivity can be increased to measure the temperature.

Further, when applied to the above-mentioned heating device, the measurement sample is placed on the placement portion and measured in a stopped state, but the placement portion is not limited to such an embodiment, and the measurement sample is placed. It can also be configured to have a moving means that makes it movable on the part.

For example, a measurement sample is conveyed into the chamber by a conveyor that passes through the inside and outside of the chamber, such as a conveyor firing furnace or a conveyor heating furnace, and the measurement sample is moved from the chamber inlet to the chamber outlet inside the chamber, and then outside the chamber again. It can be configured to transport the measurement sample to the chamber. According to such a configuration, the temperature of the measurement target can be measured in a chamber where heat treatment or the like is performed on the transported measurement sample.
<Effect of Embodiment 3>

With the radiation temperature measuring device of the present embodiment, the apparent emissivity of the measurement sample arranged in the chamber can be increased by multiple reflections, and the temperature can be accurately measured even for an object whose emissivity is unknown and fluctuating. be able to.

0101 Measurement sample 0102 Type 1 mirror 0103 Type 2 mirror 0104 Measurement surface normal 0105 Radiation thermometer 0106 Arrangement part 0107 Hole part

Claims (8)

At least the measurement surface is an arrangement part for arranging a flat measurement sample,
The light emitted from the measurement sample is reflected at an angle θ within a predetermined range with respect to the measurement surface normal line of the measurement sample placed in the arrangement portion, and is made to enter the measurement sample again. A first-class mirror configured to radiate at an angle −θ within a predetermined range with respect to
The measurement surface method of the measurement sample from the incident point by reflecting the light radiated from the measurement sample at an angle −θ within a predetermined range with respect to the measurement surface normal line of the measurement sample arranged in the arrangement portion and making it enter the measurement sample again. A second-class mirror that is configured to radiate at an angle θ within a predetermined range with respect to the line,
Consists of
The first type mirror and the second type mirror are each composed of one or more mirrors.
A radiation thermometer having a radiation thermometer for measuring radiance in which the apparent emissivity of a measurement sample is increased by the light multiplely reflected between the plurality of mirrors. A claim that the radiation thermometer is located behind a first-class mirror and / and a second-class mirror and is configured to capture the multiple-reflected light from a hole provided in a mirror in front of it. The radiation thermometer according to 1. The radiation temperature measuring device according to claim 1 or 2, wherein a polarizing portion having a p-polarizer is provided in front of the light intake surface of the radiation thermometer. The radiation temperature measuring device according to any one of claims 1 to 3, wherein the value of θ is 60 degrees or more. Has a chamber with an internal observation window
The arrangement portion is arranged in the chamber and
The first-class mirror, the second-class mirror, and the light intake surface of the radiation thermometer are arranged outside the chamber so that the light from the measurement sample is incident through the internal observation window. The radiation thermometer according to any one of claims 1 to 4. The radiation temperature measuring device according to any one of claims 1 to 5, wherein the arranging unit has a moving means for moving a measurement sample on the arranging unit. At least the measurement surface is an arrangement part for arranging a flat measurement sample,
The light emitted from the measurement sample is reflected at an angle θ within a predetermined range with respect to the measurement surface normal line of the measurement sample placed in the arrangement portion, and is made to enter the measurement sample again. A first-class mirror configured to radiate at an angle −θ within a predetermined range with respect to
The measurement surface method of the measurement sample from the incident point by reflecting the light radiated from the measurement sample at an angle −θ within a predetermined range with respect to the measurement surface normal line of the measurement sample arranged in the arrangement portion and making it enter the measurement sample again. A second-class mirror that is configured to radiate at an angle θ within a predetermined range with respect to the line,
Radiation thermometer and
Consists of
The first-class mirror and the second-class mirror are temperature measuring methods of a radiation temperature measuring device each composed of one or more mirrors.
The placement step of placing the measurement sample in the placement section and
A measurement step of measuring the radiance with a radiation thermometer in which the apparent emissivity of the measurement sample is increased by the light multiple reflected between the plurality of mirrors.
A temperature measuring method having. At least the measurement surface is an arrangement part for arranging a flat measurement sample,
The light emitted from the measurement sample is reflected at an angle θ within a predetermined range with respect to the measurement surface normal line of the measurement sample placed in the arrangement portion, and is made to enter the measurement sample again. A first-class mirror configured to radiate at an angle −θ within a predetermined range with respect to
The measurement surface method of the measurement sample from the incident point by reflecting the light radiated from the measurement sample at an angle −θ within a predetermined range with respect to the measurement surface normal line of the measurement sample arranged in the arrangement portion and making it enter the measurement sample again. A second-class mirror that is configured to radiate at an angle θ within a predetermined range with respect to the line,
Consists of
The first-class mirror and the second-class mirror are arranged in a regular N-sided shape from N mirrors, respectively.
The value of N is 3 or more and infinity or less,
A radiation thermometer having a radiation thermometer for measuring radiance in which the apparent emissivity of a measurement sample is increased by the light multiplely reflected between the plurality of mirrors.

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