A new method for temperature scale calculation of a radiation thermometer with four-point blackbody calibration data and knowledge of the shape of the spectral responsivity was developed. This method was applied to numerical models of narrow-band and wide-band infrared radiation thermometers and it was compared with conventional characteristic equations.
The developed characteristic equation has an array representing the shape of the spectral responsivity and four constants: the array S_k, the gain coefficient C₃, the offset D₃, the center wavelength λ₀ and the wavelength step d. The wavelength of S_k is given as λ₀+k·d(k=-n, …, -1, 0, 1, …, n). S_k is obtained from relative data of the spectral responsivity or rough estimation on the shape of the spectral responsivity. Then the calculation of the four constants is made from four-point blackbody calibration data. When the offset can be measured, necessary blackbody calibration data are reduced to three points.
Spectral responsivity data of a germanium photodiode were used as the numerical model of a wide-band radiation thermometer. The product of the responsivity data and spectral transmittance data of a narrowband-pass filter of an actual radiation thermometer was used as the numerical model of a narrow-band radiation thermometer.
In the case of the wide-band model, the deviation of the calculated temperature scale from the model was less than ±1°C in the range from 140°C to 1500°C when the calibration points were 231.928°C, 660.323°C and 1084.62°C, and the used shape was a Gaussian distribution. The deviation was mostly less than 1/2 of the deviation of the best conventional equation in the interpolation range and it was 1/6 at 1800°C.

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This paper proposes a 900nm silicon narrow-band radiation thermometer, which is calibrated by a set of fixed point blackbody furnaces, as for a practical temperature standard of good accuracy.
This radiation thermometer covers the temperature range from 420°C to 2000°C and its focal range extends from 40cm, of which the object area is 3mm in diameter, to infinity. The image of the measured plane is focused by an objective lens on a mirror with an aperture of 0.75mm diameter. The light passed the aperture travels through a condenser lens, through an interference filter, of which the maximum transmission wavelength is 900nm and the half width 14nm, and reaches to a silicon photo-cell to be converted into an electric current. The optical axis of the thermometer is set on to the object by using a finder system which utilizes reflected light from the mirror.
The photo-current from the silicon photo-cell is converted by a four-range FET amplifier into a voltage signal and then measured by an electronic digital voltmeter. By selecting appropriate range, a resolution of 1K at 420°C and better than 0.01K above 600°C can be obtained. When the fluctuation of room temperature is smaller than ±1K, the thermometer has a reproducibility of ±0.1K for above 600°C range.
The relation between the output voltage V(T) of this radiation thermometer and temperature T of the object can be expressed as follows:
V(T)=Cexp(-c₂/AT+B)where c₂=0.014 388m·K.
When the calibration to determine the coefficients A, B and C is made by using three fixed point blackbody furnaces of Al, Ag and Cu with precision of 0.3K, a temperature scale for practical standard of ±0.5K precision can be realized with this thermometer in the temperature range from 600 to 1100°C.

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非接触で温度の測定ができるの原理、 構造、 及び使用方法について解説する。 と同様に熱画像装置についても解説する。 また、 、 及び熱画像装置の熱物性計測への応用についても、 計量研究所で行った研究を例にして述べる。

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In this paper, a characteristic equation to show the characteristics of narrow-band radiation thermometers in the wide temperature range is investigated.
The characteristic equation is written as follows
V=Cexp(-c₂/AT+B)
where V is the output signal voltage of the radiation thermometer, T is the temperature to be measured, c₂=0.014388m·K and A, B and C are coeffcients intrinsic to the radiation thermometer. The equation can be transformed as follows
T=c₂/A/lnC-lnV-B/A
or
aT·lnV+b·lnV+c=T,
A=ac₂/(b/a+c), B=bA/a, C=exp(l/a),
The coefficients A, B and C can easily be calculated from the measured values by the least square meathod and then the temperature can directly be obtained from the output signal voltage.
When the radiation thermometer with the measuring wavelength of 0.9μm is calibrated by blackbodies at three freezing points Al, Ag and Cu with high accuracy, and when the detector sensitivity is linear, a temperature scale with accuracy of ±0.1K shall be given by the equation. In this case, the measuring wavelength width of the radiation thermometer as wide as 90nm is permitted. Such goodness of fit of the characteristic equation are discussed to three radiation thermometers of measuring wavelengths 4, 0.9 and 0.65μm.

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Spectral responsivity distributions of three 0.65μm silicon narrow-band radiation thermometers were measured from 450nm to 1200nm. The temperature scales calibrated based on the spectral responsivity agreed well with those established by the standard tungsten lamp calibration.

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Infrared radiation thermometers measuring low temperature have an inherent problem of background radiation originated in themselves because inner parts of radiation thermometers radiate as bright as measurement objects. The problem is important to multielement radiation thermometers.
To investigate background radiation of a multielement detector, angular dependence of responsivity of a 10-element InSb linear array was measured. The detector elements responded to radiation incidence from the outside of the field of view. Radiation from the outside of the field of view is mainly background radiation in an actual radiation thermometer.
We developed a new optical method to reduce background radiation incidencee of thermal infrared detectors with cooling. A mirror iris was used in the method; it was a concave mirror having an aperture for signal radiation at the center. When the mirror iris is inserted into an optical pass between the detector and a lens, the detector observes the cold image reflected in the mirror surface.
A thermal infrared radiation thermometer having the InSb array detector and the mirror iris was developed to evaluate the effect of the optical method. Zero drift of the radiation thermometer was largely reduced by the mirror iris without an optical chopper.
Stability of the radiation thermometer observing a blackbody furnace maintained at 40°C was measured. The indicated temperature drift was less than ±0.9°C when the room temperature was varied in a range of ±6°C alternatively. The drift was improved to less than ±0.2°C with a compensation using the inner temperature of the radiation thermometer.

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A standard blackbody furnace for the calibration of commercially available radiation thermometers has been developed. This furnace has a cavity of chrome plated copper walls with an opening of 60mm in diameter. The furnace is designed so that the temperature of the cavity can be easily estimated by a resistance thermometer. It is shown that the furnace has an accuracy of 1K through the comparison with two fixed point blackbodies when the effective emissivity, the size-of-source effect and the absorption by water vapor of the air are corrected for.

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A multiwavelength radiation thermometer having a hybrid detector of a 64-element silicon-germanium linear array and an infrared detector of a 48-element InSb linear array was developed for measurements of temperature and emissivity. A wide wavelength range detection by one fixed grating from 0.55μm to 1.6μm were realized by the hybrid detector. The InSb detector and a LiF prism were used for the long wavelength range from 1.3μm to 5.3μm.
The two-detector optical system without mechanical wavelength scanning and light chopping improved the stability and the response time as short as 256μs to scan a total of 112 wavelengths. In a continuous 6-month operation without optical adjustment, no wavelength drift and 5% reduction in responsivity were observed.
A reference radiation source of a plane blackbody furnace was used for the compensation of the responsivity reduction and the atmospheric absorption of the optical pass of the multiwavelength radiation thermometer.
The temperature scale and the wavelength of each detector element were calculated from calibration data. Two blackbody furnaces and 24 narrow-band-pass filters were used in the calibration. The noise equivalent. temperature differences were estimated from the temperature scales and noise data of the analog signals when the time constant of the amplifiers was 100ms and the target was a blackbody operated at 1052°C; they were 0.16°C, 0.08°C, 0.24°C, and 0.54°C at the wavelengths of 0.55μm, 0.66μm, 2.0μm, and 5.0μm, respectively.

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は,サーモグラフ同様身体に非接触で,無侵襲,計測による身体的制限が少なく,さらに温度の計測と表示が同時に可能で,機動性に優れ,廉価である。今回の研究は,を情動のモニターとして小児に応用する前段階として,成人へ応用し,その可能性を検討した。
方法は,岡山大学歯学部小児歯科診療室において,25-48歳の男女20名の鼻尖部皮膚表面温度を安静時にサーモグラフとを用い計測した。鼻尖部皮膚表面温度の変化幅(Range)と変動係数(CV)をの実測値,および平滑化した値から算出し,サーモグラフによる計測値のRange,CVと比較した。また,実際の症例における各計測値の変化を検討した。結果は実測値では有意な差が現れたが,平滑化した値では有意差はみられなかった。の値を平滑化することによって,臨床上使用可能な計測精度を導くことが可能であることが示唆された。歯科臨床においてを使用し,情動変化の生理学的指標である鼻尖部皮膚表面温度変化を捉えることが可能で,の情動のモニターとしての,歯科場面への応用の可能性が示唆された。

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