Anti-frosting low-temperature surface source blackbody

Abstract

The invention discloses an anti-frosting low-temperature surface source blackbody, which comprises a shell and a blackbody plate, a semiconductor cooler, a temperature control assembly, a heat dissipation assembly and a power module, which are arranged in the shell. The semiconductor cooler is electrically connected with the temperature control assembly, and the temperature control assembly and the heat dissipation assembly are both electrically connected with the power module; an anti-frosting assembly installed on the shell is arranged at the front end of the black body plate, and the temperature control assembly is suitable for being connected with an external computer and conducting calculation according to PID parameters to adjust the power of the semiconductor cooler. The low-temperature surface source blackbody can be effectively protected, surface frosting is avoided, and meanwhile the temperature accuracy and stability of the low-temperature surface source black body are improved.

Description

technical field [0001] The invention relates to the technical field of optical characteristics, in particular to an anti-frosting low-temperature surface source black body. Background technique [0002] A black body is an ideal object, its emissivity and absorptivity are both 1, that is, it can absorb all wavelengths of radiation at any temperature and emit radiation to the maximum. In reality, there is no ideal black body, but the black body can be approximately replaced by the equipment black body manufactured by the same principle. [0003] Equipment blackbodies are widely used in the calibration of measuring equipment such as infrared cameras and spectrometers. According to the test targets of measuring equipment such as thermal imagers and spectrometers, the black body temperature range used for infrared calibration is also different. Because the calibration blackbody equipment is exposed to the air, when performing calibration experiments below zero degrees Celsius, ...

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Problems solved by technology

Because the calibration blackbody equipment is exposed to the air, when performing calibration experiments below zero degrees Celsius, due to the large temperature difference between the air and the blackbody radiation surface, the water vapor in the air condenses on the surface of the blackbody, forming frost. The response sensitivity of the infrared sensor is greatly affected by frost, which leads to doubts about the accuracy of the measurement results, and cannot be used as the basis for calibration and traceability of infrared equipment.

[0004] Since the temperature accuracy of the low-temperature surface source blackbody directly affects the subsequent temperature transfer, in order to prevent convective heat exchange between the air and the surface source blackbody during low-temperature operation, resulting in frosting and affecting the temperature calibration of the instrument, there are three commonly used solutions: The first is to blow dry gas directly on the surface of the surface source blackbody. The advantage of this scheme is that the anti-frost effect is obvious. However, due to the difference between the temperature of nitrogen and the temperature of the surface source blackbody, the surface temperature of the surface source blackbody changes significantly, and the temperature accuracy is not high. ; The second is to encapsulate the surface source blackbody surface in a box full of dry nitrogen and seal it with an optical window. The temperature error needs to be corrected when calculating the measurement results. On the other hand, the transmittance of the optical window above 0.99 will also cause high processing costs; the third is to place the surface source blackbody and the system under test together in a cover filled with nitrogen. Inside, the advantage of this scheme is that there is no temperature error introduced by other devices between the system under test and the surface source blackbody. The distance between them varies from far to near. This kind of solution will need to install various covers for various systems under test. There are many types and large volumes, resulting in high cost.

[0005] In addition, the temperature controller of the traditional low-temperature surface source black body uses pulse voltage output to control the semiconductor refrigerator. Since the voltage waveform on the semiconductor refrigerator is a square pulse, the temperature control power has a sudden change, resulting in low temperature stability. The stability is ±1°C, and the life of the semiconductor refrigerator will be reduced due to sudden voltage changes

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