JPH0448230A - Emissivity measuring instrument - Google Patents

Abstract

PURPOSE:To measure the emissivity of infrared rays speedily with high accuracy by providing a rotary shaft which extends at right angles to the photodetection surface in the photodetection sensor of a radiometer and a mirror surface which is provided at 45 deg. to the rotary shaft opposite the photodetection surface. CONSTITUTION:This instrument is equipped with a scanning rotary mirror 1 which has the elliptic mirror surface 12 on the rotary shaft 11, the radiometer 2 which measures the radiation amount of an electromagnetic wave such as infrared rays, a low-temperature reference black body 3 for calibrating the quantity of radiation on a low-temperature side, a high-temperature reference black body 4 for calibrating the quantity of radiation on a high-temperature side, a body 5 to be tested, and a rotary mirror holder, and those are placed in a vacuum chamber held in a vacuum state. The rotary shaft 11 of the scanning rotary mirror 1 is extended at right angles to the photodetection surface 21 in the photodetection sensor which detects the electromagnetic wave in the radiometer 2 and the mirror surface 12 is fitted at 45 deg. to the rotary shaft 11 and faces the photodetection surface 21. Consequently, the emissivity of the infrared rays can be measured speedily with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an emissivity measuring device that measures the emissivity of mainly infrared rays emitted by an object.

[Conventional technology]

In conventional emissivity measurements of this type, the specimen whose emissivity is to be measured is placed in front of a radiometer that measures the amount of electromagnetic waves such as infrared radiation emitted from the object.

High-temperature reference black bodies and low-temperature reference black bodies for emissivity calibration were placed alternately to perform measurements and calibrate measured values. Measurements and calibrations were performed in the atmosphere.

[Problem to be solved by the invention]

The conventional emissivity measurement described above has the following drawbacks.

(1) Since measurement and calibration are performed in the atmosphere, electromagnetic waves emitted from the specimen are absorbed by the atmosphere, making it difficult to obtain accurate measurement values.

This absorption is particularly noticeable at wavelengths shorter than submillimeter waves.

(2) Since there is heat transport in the atmosphere by convection, it is difficult to obtain a reference black body at an extremely low temperature or a high temperature while consuming a small amount of energy.

Therefore, it is difficult to create a large temperature difference between the two temperatures of the low-temperature reference blackbody and the high-temperature reference blackbody, making accurate calibration difficult.

(3) During measurement, it is necessary to replace the specimen and the standard blackbody for calibration, so it takes a long time to perform the measurement.

(4) In order to measure the radiation amount dependence, which represents the change in radiation amount depending on the emission (radiation) direction of electromagnetic waves from the specimen, move either the specimen or the radiometer and adjust the facing angle between the two. It is necessary to change and measure.

[Means to solve the problem]

The emissivity measuring device of the present invention includes a radiometer that measures the amount of radiation of electromagnetic waves including infrared rays, a rotating shaft provided extending perpendicularly to a light-receiving surface in a light-receiving sensor of the radiometer, and the rotating shaft. a scanning rotating mirror having an angle of 45° and a mirror surface provided on the side opposite to the light receiving surface and scanning around the rotation axis; the entire radiometer or the light receiving sensor; and the scanning rotating mirror. It has a vacuum chamber that maintains a vacuum state.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1(a) is a partially cutaway side view of an embodiment of the reflectance measuring device according to the present invention, and FIG. 1(b) is a front view of the same.

1 is a scanning rotary mirror with an elliptical mirror surface 12 attached to a rotating shaft 11; 2 is a radiometer that measures the amount of radiation of electromagnetic waves such as infrared rays; and 3 is a low-temperature reference blackbody for calibrating the amount of radiation on the low-temperature side. , 4 is a high temperature reference black body for calibrating the radiation amount on the high temperature side, 5 is a specimen, and 6 is a rotating mirror holder. These are placed in a vacuum chamber (not shown) that keeps each of the aforementioned components under vacuum. In the radiometer 2, only the light receiving sensor portion that detects electromagnetic waves may be placed in a vacuum chamber.

A rotating shaft 11 of the scanning rotating mirror 1 is provided to extend in a direction perpendicular to a light receiving surface 21 in a light receiving sensor that detects electromagnetic waves in the radiometer 2, and is attached to a rotating mirror holder 6. The mirror surface 12 is attached to the rotating shaft 11 at an angle of 45 degrees, and the zero-rotation mirror holder 6 provided on the side opposite the light-receiving surface 21 allows the mirror surface 12 of the scanning rotating mirror 1 to rotate around the rotating shaft 11. It is sized to protect within the rotation range. Figure 1 (a
) and (b), the rotating mirror holder 6 has a rectangular parallelepiped shape. Low temperature reference blackbody 3. The objects to be measured for which the radiation amounts of the high-temperature reference black body 4 and the specimen 5 are to be measured are placed at different locations outside the rotating mirror holder 6, that is, facing different surfaces perpendicular to the rotation axis 11. It's dark. These objects to be measured may be installed on the outer surface of each rotating mirror holder 6.
The zero-rotation mirror holder 6 can easily install as many objects to be measured for emissivity measurement as there are faces, not only with four faces, but also with the maximum number of faces. 12 and between the mirror surface 12 and the light-receiving surface 21.

Here, the mirror surface 12 is a mirror that reflects infrared rays with little loss, such as a polished aluminum plate or a gold-plated plate, if the electromagnetic wave 9, for example, the electromagnetic wave whose emissivity is to be measured, is infrared rays. (Hereinafter, electromagnetic waves will be represented by infrared radiation,
It is called synchrotron radiation. This measuring device measures the "radiation amount" of electromagnetic waves.
Since it is a device that measures
Since the energy radiated from the specimen 5 differs depending on the physical properties of the specimen 5, the "emissivity" which is a value specific to this physical property value is measured, and therefore it is called an "emissivity" measuring device. )
The low-temperature reference black body 3 is, for example, a high-emissivity object made of copper or the like with good thermal conductivity, which has irregular grooves on its surface and is painted black, and which is heated to an extremely low temperature with liquid helium or the like. It is cooled. The high temperature reference black body 4 is, for example, made of a thick plate made of the same material as the low temperature reference black body 3, subjected to the same surface treatment, and further heated with a heater to stabilize the temperature. These cooling or heater heating are
Because it is carried out in a vacuum, there is no heat transport by convection, and heating and
Less energy is required for cooling than in the atmosphere.

Now, the rotation shaft 11 of the scanning rotation mirror 1 is rotated in the illustrated rotation direction, that is, in the horizontal direction to the light receiving surface 21 of the radiometer 2. Then, the mirror surface 12 rotates in a tangled manner, and the mirror surface 12 is scanned once for each rotation of the rotating shaft 11. During this one scan,
The synchrotron radiation aperture emitted from the high-temperature reference blackbody 4, the synchrotron radiation A emitted from the low-temperature reference blackbody 3, and the synchrotron radiation C to H emitted from the specimen 5 are reflected by the mirror surface 1, and are reflected by the radiometer 2.
reaches the light-receiving surface 21 of. Then, each radiation amount is measured by the radiometer 2. Since this synchrotron radiation propagates in a vacuum, where there are no substances that absorb or scatter electromagnetic waves like in the atmosphere, the amount of radiation can be measured accurately. Here, the radiation beam 2 is at an angle from a plane perpendicular to the infrared radiation surface of the specimen 5, that is, the emission angle is 0°, and the radiation beams C and H have a constant emission angle. This is the case.

In this emissivity measuring device, the emissivity can be measured over a predetermined angular range as the mirror surface 12 is scanned, and the dependence of the emissivity in the scanning direction on the output angle can be measured.

FIG. 2 shows the radiation amount measured by the radiometer 2 with respect to the rotation angle of the scanning rotary mirror 1 in the embodiment of FIG. 4, at one rotation angle of 90°, the low temperature reference black body 3
The radiation amount of the specimen 5 is measured at one rotation angle of 180°. In this way, the radiation amount of all objects to be measured can be measured during one scan of the scanning rotary mirror 1.

〔Effect of the invention〕

As explained above, according to the present invention, the emissivity of electromagnetic waves, especially infrared rays, emitted by a specimen can be measured with high precision and quickly, and the dependence of the emissivity of the specimen on the emission angle can be easily measured. .

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are a partially cutaway side view and a front view of an embodiment of the present invention, and FIG. 2 is a diagram showing the results of radiation measurement according to the embodiment. DESCRIPTION OF SYMBOLS 1... Scanning rotating mirror, 2... Radiometer, 3... Low temperature reference black body, 4... High temperature reference black body, 5... Specimen, 6...
...Rotating mirror holder, 11...Rotating shaft, 12...Mirror surface, 21...Light-receiving surface, A~F...Radiant light.

Claims (1)

[Claims] 1. A radiometer that measures the amount of radiation of electromagnetic waves including infrared radiation;
The radiometer has a rotating shaft extending perpendicularly to the light receiving surface in the light receiving sensor of the radiometer, and a mirror surface provided at an angle of 45° to the rotating shaft and on a side opposite to the light receiving surface. An emissivity measurement device comprising: a scanning rotating mirror that scans around a rotation axis; and a vacuum chamber that maintains the entire radiometer or the light receiving sensor and the scanning rotating mirror in a vacuum state. 2. An emissivity measuring device comprising: the emissivity measuring device according to claim 1; and means for arranging objects having a plurality of radiation amounts outside the rotation range of the scanning rotating mirror.