| 摘要 |
PURPOSE:To enable only the infrared radiation from the region Z of good heat equalizing characteristic to be detected by providing a portion of lower emissivity within the black body furnace in the black body furnace for temperature calibration of a thermography apparatus. CONSTITUTION:Heating wires 2 are wound on the circumference of a furnace core part 1 and a cavity 3 is provided therein to increase the emissivity of the inside surface. Further, a heat insulating material 4 and shield plate 5 are provided on the front face. An annular pleat 6 is provided in the position close to the region Z where heat equalizing characteristic within the cavity 3 and the face G thereof facing the outside is made lower in emissivity by metal gloss. When the focal length of the optical system is so controlled that the rise or fall of the portion of the detection signal when the luminous flux LB of the thermography apparauts scans the black body furnace becomes sharpest, then the optical system may be focused at the edge part F' of the pleat 6 and if scanning is made by the luminous flux LB of the same opening angle theta, the period T while scanning the region Z becomes longer and temperature calibration is accurately accomplished. |
