JPH0599749A - Non-contact temperature measuring method - Google Patents

Abstract

PURPOSE:To perform accurate optical measurement without receiving any influence from emissivity at the time of performing non-contact temperature measurement by only measuring the wavelength-modulated spectrum of radiation spectrum from a measuring section. CONSTITUTION:The light emitted from a measuring section 1 is condensed into an optical fiber 3 through a lens 2 and, after the light is modulated by means of a chopper 4 which is operated by chopper driver 4, sent to a spectroscope 6 by which the light is dispersed into its spectral components. The wavelength of the dispersed light is periodically changed immediately before an exist slit by periodically vibrating a quartz plate 8 by means of a wavelength modulation driver 7. The light coming out from the spectroscope 6 is detected by means of a multiplier phototube 9 and the wavelength variation L against the wavelength of the originally emitted light is measured by means of a lock-in amplifier 10, while the intensity L of the originally emitted light is measured by means of another lock-in amplifier 11. The outputs of the amplifiers 10 and 11 are latched into a personal computer 12 which processes the outputs and displays a temperature. The wavelength of the spectroscope 6 is set by means of a spectroscope controller 13.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a non-contact temperature measuring method.

[0002]

2. Description of the Related Art A two-color thermometer is a typical technique that uses optical means as a non-contact temperature measuring method, and it measures temperature from the intensity ratio of light intensity of two different wavelengths emitted from a measuring section. When the emissivity of the measurement unit is close to 1, that is, when black body radiation can be assumed, highly accurate temperature measurement can be performed. However, in ordinary optical temperature measurement, the emissivity is a function of temperature and wavelength and is affected by the surface condition and the measurement atmosphere, so such a method is used when measuring an object whose emissivity is unknown. Contains a lot of errors, and thus there is a need to establish a technique for reducing the error of the temperature measurement due to the emissivity during the temperature measurement.

[0003]

SUMMARY OF THE INVENTION The present invention has been proposed in view of such circumstances, and it is possible to accurately and optically measure temperature without being affected by the emissivity of the temperature measuring section. An object is to provide a non-contact temperature measuring method.

[0004]

Therefore, in the present invention, when the temperature measuring section is opposed to an optical measuring system including a spectroscope to measure the temperature in a non-contact manner, the wavelength modulation of the radiation spectrum from the temperature measuring section is performed. Characterized by measuring a spectrum.

[0005]

In the non-contact temperature measuring method of the present invention, in order to reduce the influence of emissivity and perform more accurate temperature measurement,
Wavelength modulation spectroscopy is used. This is a method of obtaining the first-order derivative of the intensity of the radiation spectrum from the measurement unit with respect to the wavelength, and the wavelength is periodically changed immediately before the exit slit inside the spectroscope.

[0006]

FIG. 1 shows an embodiment of the non-contact temperature measuring method of the present invention.
The system diagram will be described. In FIG. 1, light emitted from the measurement unit 1 is collected by a lens 2, introduced into an optical fiber 3, modulated by a chopper 5 operated by a chopper driver 4, and then incident from an entrance slit of a spectroscope 6. The light dispersed in the spectroscope 6 periodically vibrates the quartz plate 8 by the wavelength modulation driver 7 immediately before the exit slit to periodically change the wavelength. The light emitted from the spectroscope 6 is detected by the photomultiplier tube 9, and the change ΔL with respect to the wavelength of the emitted light is measured by the lock-in amplifier 10, while the intensity L of the emitted light is measured by the lock-in amplifier 11. Each output is captured by the personal computer 12, and the processing and temperature are displayed. The wavelength of the spectroscope 6 is set by the spectroscope controller 13.

Therefore, the influence of the emissivity in the wavelength modulation spectroscopy is reduced as follows. That is, generally, the luminance L (λ,
T) is given by the Planck's equation as in Equation 1, and can be represented by Equation 2 on the short wavelength side of the spectrum, and the first derivative with respect to the wavelength in this equation can be represented by Equation 3. Here, since the derivative of the emissivity of the first item on the right side with respect to the wavelength can be ignored as compared with the other terms, it is possible to obtain Formula 4. Therefore,
When the temperature T is transformed from the equation 4, the equation 5 is obtained. Where dL
Since (λ, T) / dλ can be obtained from the wavelength modulation spectrum and L (λ, T) is the emission intensity, it is possible to determine the temperature without being affected by the emissivity from the equation (5). ..

[Equation 1]

[Equation 2]

[Equation 3]

[Equation 4]

[Equation 5]

[0008]

In summary, according to the present invention, the wavelength modulation spectrum of the radiation spectrum from the temperature measuring unit is measured when the temperature is measured in a non-contact manner with the optical measuring system including the spectroscope facing the temperature measuring unit. By doing so, a non-contact temperature measuring method that can accurately perform optical temperature measurement without being affected by the emissivity of the temperature measuring section is obtained, and therefore the present invention is extremely useful industrially.

[Brief description of drawings]

FIG. 1 is a system diagram of an apparatus for implementing an embodiment of the non-contact temperature measuring method of the present invention.

[Explanation of symbols]

 1 Measuring Part 2 Lens 3 Optical Fiber 4 Chopper Driver 5 Chopper 6 Spectrometer 7 Wavelength Modulation Driver 8 Quartz Plate 9 Photomultiplier Tube 10 Lock-in Amplifier 11 Lock-in Amplifier 12 Personal Computer 13 Spectroscope Controller

Front page continued (72) Inventor Nobuyuki Fukuda 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries Ltd. Hiroshima Works

Claims (1)

[Claims] 1. A non-contact type temperature-measuring device which measures a wavelength modulation spectrum of a radiation spectrum from the temperature measuring unit when an optical measuring system including a spectroscope is opposed to the temperature measuring unit to measure the temperature in a non-contact manner. Contact temperature measurement method.