| 摘要 |
PURPOSE:To improve the measurement accuracy of a thermometer and to miniaturize it by boring plural different openings in a measurement area control plate and using the openings alternately. CONSTITUTION:An electric conductor 1 to be measured, a lens 13, a detector 16, the measurement control plate 14 which is right before the detector 16 and limits the measurement range of the radiation thermometer, etc., are provided. Further, the apertures 21 and 22 which are different in the ratio of the electric conductor 1 are provided and the lens 13 is a rectangular plate capable of setting the apertures 21 and 22 in front of the detector 16 properly by a driving device and forms the image of the electric conductor 1 on the control plate 14. The apertures 21 and 22 are rectangular and have short sides (c) equal in length, and the long sides d2 of the aperture 22 are longer than the long sides d1 of the opening 21. In projection images by the lens 13 at the positions of the electric conductor 1 in the two apertures 21 and 22, the short sides are as large as the wire diameter D of the electric conductor 1, the long sides of the projection 4 is three times the wire diameter D, and the long sides of the projection 5 is about four times the wire diameter D. Consequently, a real measurement and a background radiation measurement are both taken by one thermometer, which is reducible in size.
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