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Two-color infrared thermometer for measuring polysilicon material in ingot furnace
- 2019-04-19-

Polysilicon is a form of single-crystal silicon, and its purity is lower than that of single-crystal silicon. It can be used as a raw material for drawing single-crystal silicon. Polysilicon is produced by a polysilicon ingot furnace. In the production of polysilicon, a high-purity polysilicon material is charged into an ingot furnace, and after being evacuated, the silicon material is melted into a liquid state. Through the automatic operation of the ingot furnace, the silicon material forms a vertical temperature gradient. The liquid silicon slowly recrystallizes from the bottom to the top to form a large-crystal polycrystalline silicon ingot. The silicon ingot is annealed and cooled out of the furnace to complete the entire ingot process.

At present, the main traditional processes of polysilicon production in the world are: improved Siemens method, silane method and fluidized bed method. Among them, the capacity of polysilicon produced by the improved Siemens process accounts for about 80% of the world's total capacity . Silicon materials are relatively difficult to measure objects, and infrared thermometers need special narrow-band color filters to reduce the effects of emissivity changes. Generally, a short-wavelength two-color thermometer is used to measure the temperature of the polysilicon liquid surface.

Two-color infrared thermometer is a kind of infrared thermometer. That is to measure the infrared radiation brightness emitted by an object in two different spectral ranges and infer the temperature of the object from the ratio of the two radiation brightness, which is called a two-color thermometer. In fact, two-color thermometers do not have the meanings of brightness and color. Here, the meaning of "color" should be infrared wavelength or spectrum, that is, "two-infrared spectral thermometer".


Two-color infrared thermometers have unparalleled advantages over single-color infrared thermometers:

1 / Can basically eliminate the impact of the measured target emissivity on the temperature measurement results.

2 / The measured target is very small, not full of field of view, and the presence of smoke and dust on the measurement route will not have a significant impact on the measurement result.

The working temperature of the 3 / two-color thermometer is mainly in the middle and high temperature areas.

4 / High accuracy, fast response speed and high distance coefficient.

Where the measured temperature is high, the emissivity is difficult to determine, the target is too small to fill the field of view, and the situation of attenuation of radiant energy substances on the measurement line, you can use the two-color infrared thermometer to solve the problem of accurate temperature measurement, while the monochrome measurement Thermometers are more difficult to solve the above problems.

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