JPH1123370A - Multicolor radiation thermometer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multicolor radiation thermometer by which condensed radiant light is guided to a photodetector with good efficiency when the radiant light is spectrally diffracted by using an optical fiber and a narrow-band- wavelength filter and by which a temperature can be measured with high accuracy. SOLUTION: Radiant light 2 which is radiated from an object 1 to be measured is condensed by an optical fiber 4. In a multicolor radiation thermometer, the optical fiber 4 is branched so as to be a T-shape, a narrow-band-wavelength filer 10 is inserted into a T-shape part so as to be tilted at 45 deg., only the radiant light at a specific wavelength is transmitted through the narrow-band-wavelength filter 10, the radiant light, at the measuring wavelength, which is not transmitted through the narrow-band-wavelength filter is bent at 90 deg., and the radiant light, at the specific wavelength, which is transmitted through the narrow-band- wavelength filter is introduced into a branch optical fiber 11 so as to be conveyed up to a photodetector 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the temperature of an object to be measured by detecting radiation emitted by the object at a plurality of wavelengths,
The present invention relates to a multicolor radiation thermometer that calculates a temperature of an object using a detected signal. In particular, the present invention relates to a multicolor radiation thermometer used when the temperature of an object to be measured such as a locally heated metal surface rapidly changes like welding.

[0002]

2. Description of the Related Art A conventional multicolor radiation thermometer will be described with reference to FIG. The polychromatic radiation thermometer includes a lens 3 for receiving radiation 2 radiated from an object 1 to be measured, an optical fiber 12 for dispersing the radiation, and a narrow-band wavelength filter 1.
0, a photodetector 6 for detecting the intensity of radiated light at each wavelength, and an arithmetic unit 9 for processing a signal passed through a signal amplifier 8 and an AD converter 9.

The optical fiber 12 is composed of a plurality of single-core optical fibers, and the entrance side of the radiated light 2 is bundled into one, and the exit side is bundled in equal numbers.
Narrow-band wavelength filters 11 are attached to the outlets, respectively, and only the radiation of a specific wavelength transmitted through the narrow-band wavelength filter 11 is detected by the photodetector 6 among the divided radiation.

By changing the transmission wavelength of each narrow-band wavelength filter 11, the intensity of the radiated light 2 at a different wavelength by the same number as the number of branches of the optical fiber 12 is detected. The detected signals at the respective wavelengths are accumulated in the arithmetic unit 9 through the signal amplifier 7 and the AD converter 8, and after performing necessary processing such as sensitivity correction, the radiant light intensity at each wavelength is determined.
These values are applied to an appropriate equation to determine the temperature of the object.

[0005] Such a multicolor radiation thermometer is described in, for example, JP-A-5-231944 and JP-A-7-167713.

[0006]

The radiated light 2 emitted from the measuring object 1 includes light of various wavelengths, and the amount of light of which wavelength is mainly determined by the temperature of the object 1. Dependent. If only a specific wavelength is extracted using the narrow-band wavelength filter 10 from the mixture, the amount of light is significantly reduced.
In order to measure the temperature with high accuracy, it is desirable to receive as much radiation 2 as possible and to increase the detection signal at each wavelength.

However, in the above prior art, the radiated light is split by the optical fiber 12, and then the light of the target wavelength is extracted by the narrow band wavelength filter 10 attached to the exit of the optical fiber 12, so that the target wavelength There is a problem that there is radiated light of the wavelength which does not reach the photodetector 6 for detecting a certain specific wavelength.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multicolor radiation thermometer capable of efficiently guiding collected radiation to a photodetector and accurately measuring temperature when the radiation is spectrally separated using an optical fiber and a narrow-band wavelength filter. Is to provide.

[0009]

As a means for achieving the above object, a narrow-band wavelength filter is sequentially inserted into an optical fiber, and a branch for sequentially extracting only radiated light of a specific wavelength at the insertion point. The fiber is provided.

Further, as another means for achieving the above object, an optical filter that reflects only light of a specific wavelength is used in place of the narrow-band wavelength filter.

In the means for achieving the above object, since a narrow-band wavelength filter is sequentially inserted into the optical fiber, all of the received radiated light is sequentially reflected by the respective narrow-band wavelength filters, and each of the narrow-band wavelength filters is sequentially reflected. Since only radiation of a specific wavelength transmitted through the wavelength filter is extracted by the branch fiber, radiation of the target wavelength is not wasted.

In another means for achieving the above object, an optical filter that reflects only light of a specific wavelength is used in place of the narrow-band wavelength filter. Since the radiation light of a specific wavelength that is sequentially transmitted through each optical filter and reflected by each optical filter is extracted by the branch fiber, the radiation light of the target wavelength is not wasted.

[0013]

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

FIG. 1 shows the configuration of an embodiment of the present invention. A lens 3 for receiving radiation 2 radiated from the object 1 to be measured, an optical fiber 4 for introducing the collected radiation 2,
Dispersing means 5 for extracting only light of a specific wavelength of interest and branch fiber 11 for extracting only light of a specific wavelength
And a photodetector 6 for detecting the intensity of the radiated light at each wavelength, and an arithmetic unit 9 for processing a signal passed through a signal amplifier 7 and an AD converter 8.

FIG. 3 schematically shows the structure of the spectroscopy means 5 comprising a single-core optical fiber 4 and a narrow-band wavelength filter 10. The optical fiber 4 is branched into a T-shape, and a narrow-band wavelength filter 10 is inserted into the T-shape at an angle of 45 degrees.

Only the light of a specific wavelength transmits through the narrow-band wavelength filter 10, and the radiated light of the remaining wavelength that has not passed through the narrow-band wavelength filter 10 is bent by 90 degrees. If T-shaped portions are provided by the number required for the measurement and the transmission wavelength of the narrow-band wavelength filter 10 is changed, the radiated light can be used without waste.

In this embodiment, seven narrow-band wavelength filters 10 are used, and each transmission wavelength has a center wavelength of 450 n.
m, 500 nm, 550 nm, 600 nm, 650 n
m, 700 nm, and 750 nm. Further, since the full width at half maximum of each transmitted light is 10 nm, they do not interfere with each other.

Light having a specific wavelength transmitted through the narrow-band wavelength filter 10 is introduced into the branch fiber 11 and carried to the photodetector 6. The signal at each detected wavelength is
After being stored in the arithmetic unit 9 through the signal amplifier 8 and the AD converter 9 and performing necessary processing such as sensitivity correction, the radiant light intensity at each wavelength is determined, and the measured object 1 is a gray body. Was determined as the temperature.

Comparing the spectroscopic means 5 of this embodiment with the conventional spectroscopic means using an optical fiber 12 having a branched outlet shown in FIG. 2, when the same amount of radiation is received, the received radiation In the present embodiment, the signal is almost wasted. Therefore, in the present embodiment, a signal about seven times as large as that in the related art is detected by the photodetector 6.

In the above embodiment, the center wavelength of the radiated light to be measured is in the range of 450 nm to 750 nm. However, another wavelength can be selected according to the temperature of the object 1 to be measured. Further, the number of wavelengths to be measured is not limited to seven.

Next, an embodiment in which an optical filter 13 that reflects only light of a specific wavelength is used instead of the narrow-band wavelength filter 10 will be described with reference to FIG.

The embodiment is the same as that of the embodiment shown in FIG. When the optical filter 13 is inserted into the T-shaped portion of the optical fiber 4 at an angle of 45 degrees, light of a specific wavelength is bent by 90 degrees, and light of other wavelengths goes straight. Also in the present embodiment, if the number of T-shaped portions required for measurement is provided and the reflection wavelength of the optical filter 13 is changed, the radiated light can be used without waste.

[0023]

According to the present invention, since the narrow-band wavelength filters are sequentially inserted into the optical fiber, all the radiated light received is sequentially reflected by the respective narrow-band wavelength filters and transmitted by the respective narrow-band wavelength filters. Since only the radiated light of the specified wavelength is extracted by the branch fiber, the radiated light of the target wavelength is not wasted, and accurate temperature measurement is possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional example.

FIG. 3 is a schematic view of a spectroscopy unit according to the embodiment of the present invention.

FIG. 4 is a schematic view of a spectral unit according to another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Measurement object, 2 ... Radiation light, 3 ... Lens, 4 ... Optical fiber, 5 ... Spectral means, 6 ... Photodetector, 7 ... Signal amplifier,
8 AD converter, 9 arithmetic unit, 10 narrow-band wavelength filter, 11 branch fiber, 12 conventional optical fiber, 13 optical filter that reflects only light of a specific wavelength.

Claims (2)

[Claims] A means for receiving radiation emitted from an object to be measured; a means for dispersing the radiation into a plurality of different wavelengths; a means for detecting the intensity of the dispersed radiation; A multicolor emission thermometer having means for calculating the temperature of the object to be measured by processing, the means for dispersing the radiant light comprises an optical fiber and a plurality of narrow-band wavelength filters having different wavelengths of transmitted light, And a multicolor radiation thermometer, wherein the narrow-band wavelength filter is sequentially inserted into the optical fiber, and a branch fiber for sequentially extracting only radiation light transmitted through the narrow-band wavelength filter is provided at the insertion point. . 2. The multicolor radiation thermometer according to claim 1, wherein
A polychromatic radiation thermometer, wherein the means for dispersing the radiated light comprises an optical fiber and an optical filter that reflects only light of a specific wavelength.