抄録
The method introduced in this paper follows the principle of the zero-derivative method to measure the temperature of a surface accurately. An elaborate innovation has been materialized in the measuring system manufactured and experimented by the authors. The measuring system enables us to measure the temperature of the surface only by a single contact of the sensor with the surface. The data obtained by the contact are processed through the data-handling circuit automatically. The sensor is an assembly of four sheathed thermocouples forming a sensing area of 4×8mm2. Two of the thermocouples are heated and simultaneously the other two are cooled by the separate base plates whose temperatures are controlled by Peltier elements. While the sensor is brought in contact with the measured surface, the transient temperatures of the hot and cold thermocouples are recorded and processed for computation in the specially designed data handling system. The data handling includes differentiation, peak-holding, taking a least square and displaying the measured surface temperature.
The measuring system has been put to test by measuring the known surface temperature. A good repeatability and an accuracy of ±0.1°C have been confirmed. The system has been applied to measure the temperature of human skin. The comparison between the values measured by this method and an infrared radiometer shows an interesting result that the emissivity of human skin is not 1.0 as generally assumed, but 0.6-0.7.
The paper will describe the measuring system, the instrumentation, the experimental setup and the test data.
