A surface source black body target surface containing a multi-scale composite microporous structure

Abstract

The application discloses a surface source blackbody target surface containing a multi-scale composite micropore structure and belongs to the field of infrared detection equipment calibration. The surface source blackbody can be used as a standard radiation source for embedded real-time calibration of an airborne / munition-borne infrared detector, the effective emissivity of the surface micropore structure still has good radiation performance for a relatively wide medium-long infrared wave band, the high-thermal-conductivity composite material replaces traditional copper or aluminum material, greatly alleviates the problem of temperature non-uniformity caused by the inverted conical micropore structure, and meets the demand of infrared detection equipment radiation calibration under an airborne / munition-borne medium-low temperature vacuum environment.

Description

Technical Field

[0001] This invention belongs to the field of infrared detection equipment calibration technology, and particularly relates to a surface source blackbody target with a multi-scale composite microporous structure. Background Technology

[0002] Currently, infrared detection equipment is experiencing rapid development in my country's military field, with widespread applications in weapon guidance, night vision reconnaissance, satellite remote sensing measurement, and temperature field situational awareness. In the civilian sector, it is used in resource exploration, power line inspection, and field search and rescue. The application of infrared detection across the entire temperature range and in multiple scenarios has led to higher demands on the accuracy of infrared detection equipment. With the development of infrared technology, blackbody radiation sources, as infrared calibration devices, have evolved from high-temperature cavity blackbody sources to medium- and low-temperature surface source blackbody sources, requiring higher performance indicators such as effective emissivity, temperature uniformity, and temperature stability.

[0003] During calibration, the closer the effective emissivity of a blackbody radiation source is to 1, the higher the calibration accuracy of the infrared equipment. To meet the high emissivity requirement, the height of the microcavity structure on the surface of the blackbody is generally increased, which leads to uneven temperature distribution of the blackbody radiation source and affects the blackbody radiation performance. Therefore, both effective emissivity and temperature uniformity are indicators characterizing the radiation properties of a blackbody, and resolving the contradiction between the two is a pressing challenge that needs to be overcome.

[0004] Blackbody radiation sources used in airborne / missile-borne optoelectronic pods generally need to meet the characteristics of working in a vacuum cryogenic environment, integration, and miniaturization. However, the blackbody radiation sources currently available in China are large in size and heavy in weight, and the effective emissivity of the blackbody target surface is low and the temperature uniformity is poor, which cannot meet the requirements of miniaturization and idealization of infrared detector calibration equipment in the military field. Summary of the Invention

[0005] This invention provides a surface-source blackbody target with a multi-scale composite microporous structure, which solves the contradiction between the effective emissivity and temperature uniformity of blackbody, and can have good radiation performance in the mid- and long-infrared spectrum, meeting the requirements of miniaturization and idealization of airborne / missile-borne embedded surface-source blackbody.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A surface-source blackbody target with a multi-scale composite microporous structure, the target surface comprising: a substrate and a coating, wherein multiple composite-size microporous structures are disposed on the substrate; the surface where the micropores are located is the blackbody target surface, and the coating is sprayed onto the surface of the microporous structures to improve the effective emissivity of the blackbody target surface; the composite-size micropores are millimeter-scale micropores and μm-scale micropores, and the millimeter-scale micropores and μm-scale micropores are arranged in a matrix, with every four millimeter-scale micropores surrounding one μm-scale micropore to form an array; the distance between each μm-scale micropore array is the surface pore diameter of the millimeter-scale micropores.

[0007] In the structure described above, the effective radiation area of ​​the blackbody target surface is 42mm × 42mm; The substrate material is a high thermal conductivity diamond / aluminum composite material with a thermal conductivity greater than 600 W / m·K; Each micropore structure is an inverted cone shape; the bottom diameter of each mm-level micropore is 1 mm, and the cone angle of the inverted cone is 36°; the bottom diameter of each μm-level micropore is 50 μm, and the cone angle of the inverted cone ranges from 15° to 25°. The coating is an ultra-black coating with an emissivity higher than 0.95; The axial temperature difference of the surface source blackbody was simulated using the finite element method. The calculation showed that the axial temperature difference of the surface source blackbody was less than 0.05K when the working temperature was 230K~400K. The radiation performance of the surface source blackbody was simulated and calculated using the Monte Carlo inverse tracing method. The calculated effective emissivity of the blackbody target surface is greater than 0.98.

[0008] Beneficial effects: This invention provides a surface-source blackbody target with a multi-scale composite microporous structure. The substrate is made of high thermal conductivity diamond / aluminum composite material, replacing traditional copper or aluminum materials, which improves the service life of the surface-source blackbody and greatly alleviates the non-uniformity of target surface temperature caused by the microporous structure. In addition, the μm-scale micropores in the multi-scale composite micropores are distributed between the mm-scale micropores, filling the part with low emissivity between the mm-scale micropores and effectively improving the target surface emissivity. Furthermore, the multi-scale micropores enable the blackbody to still have good radiation performance in a wide mid- and long-infrared band, meeting the miniaturization and idealization requirements of infrared detector calibration equipment in low-temperature vacuum environments on airborne / missile-borne systems. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the surface blackbody target structure in an embodiment of the present invention; Figure 2 This is a top view of the surface source blackbody target and a magnified view of the composite micropores in an embodiment of the present invention; Figure 3 As described in the embodiments of the present invention Figure 2 Cross-sectional view at point AA; Figure 4 As described in the embodiments of the present invention Figure 2 Cross-sectional view of BB section; Figure 5 This is a simulation result of the effective emissivity of the surface source blackbody target in an embodiment of the present invention; Figure 6 This is a simulation result of the axial temperature difference of the surface source blackbody target in an embodiment of the present invention; The labels in the figure mean: 1-substrate; 2-mm-level micropores; 3-μm-level micropores; 4-coating. Implementation

[0010] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments: like Figure 1 and 2 As shown, a surface-source blackbody target with a multi-scale composite microporous structure includes a substrate 1, mm-level micropores 2, μm-level micropores 3, and a coating 4. The surface where the micropores are located is a blackbody target, and the effective aperture of the target is 42mm×42mm. The coating is sprayed onto the surface of the micropores.

[0011] like Figure 3 and 4 As shown, mm-level micropores are distributed in a matrix on the substrate. The micropores are inverted conical in shape, with a bottom diameter of 1 mm and a cone angle of 36° for each inverted cone. Every four mm-level micropores surround an array of μm-level micropores. The distance between each μm-level micropore array is the surface pore diameter of the mm-level micropores. The μm-level micropores are inverted conical in shape, with a bottom diameter of 50 μm and a cone angle of 15° to 25° for each inverted cone.

[0012] The substrate 1 uses a commercially available diamond / aluminum composite material with a thermal conductivity greater than 600 W / m·K to replace traditional copper or aluminum materials. The high thermal conductivity of this material improves the thermal conductivity and greatly alleviates the problem of uneven target surface temperature caused by the microporous structure. At the same time, the coefficient of linear expansion of the composite material can be changed by the ratio to match the coefficient of linear expansion of the ceramic cover plate of the semiconductor cooling device.

[0013] To meet the miniaturization requirements for embedded real-time calibration of airborne / missile infrared detectors, the overall size of the surface-source blackbody target is 42mm×42mm×2mm. The surface-source blackbody is thin and made of a high thermal conductivity material, which greatly improves the efficiency and temperature uniformity during the heating and cooling of the blackbody.

[0014] To improve the effective emissivity of the blackbody target, an ultra-black coating with an emissivity greater than 0.95 needs to be sprayed onto the surface of the microporous structure. In addition, to meet the requirements of the medium and low temperature vacuum calibration environment, a coating that can withstand the vacuum environment, has strong adhesion, and has an operating temperature range of 230K~400K should be selected.

[0015] like Figure 5As shown, in this embodiment, the Monte Carlo inverse tracing method is used to simulate the effective emissivity of the blackbody target surface. The emissivity of the blackbody surface coating is set to 0.97, the radiative flux of the tracing light source is set to 1, and a blackbody target surface structure with a micro-aperture cone angle of 36° on the mm scale and a micro-aperture cone angle range of 15°~25° on the μm scale is selected for simulation calculation of reflectivity. The calculation shows that the blackbody target surface has a low reflectivity, that is, a high effective emissivity, and the emissivity is greater than 0.98.

[0016] like Figure 6 As shown, in this embodiment, the axial temperature difference and target surface temperature uniformity during the heating and cooling of a blackbody target surface are simulated using the finite element method. The bottom temperature boundary condition of the blackbody is set to the blackbody operating temperature, i.e., 230K and 400K. The radiation boundary condition of the blackbody target surface is set to the effective emissivity of the blackbody, i.e., 0.98. A blackbody target surface structure with a micropore cone angle of 36° on the mm scale and a micropore cone angle range of 15°~25° on the μm scale is selected for simulation calculation. The calculation shows that the axial temperature difference of this micropore structure is less than 0.05K at both operating temperatures.

[0017] In this embodiment, the specific technical specifications achieved by the surface-source blackbody target are as follows: Effective aperture of the surface-source blackbody target: 42mm × 42mm; Effective emissivity of the target surface: >0.98; Axial temperature difference of the blackbody source: <0.05K; The aforementioned surface-source blackbody target with multi-scale composite microporous structure effectively mitigates the contradiction between the effective emissivity and temperature uniformity of the surface-source blackbody target. Furthermore, the μm-scale micropores can fill the portion with low emissivity in the mm-scale micropore array, further improving the effective emissivity. In addition, the mm-scale and μm-scale micropore sizes are still larger than the mid- and long-infrared wavelengths. Infrared light entering the composite-size micropores can be enhanced by multiple reflections. According to Kirchhoff's law, absorptivity equals emissivity, and this structure has a significant effect on improving emissivity. Therefore, the multi-scale composite micropore structure still has good radiation performance over a wide infrared band.

[0018] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A surface-source blackbody target with a multi-scale composite microporous structure, characterized in that, The surface-source blackbody target surface includes: a substrate and a coating. Multiple composite-sized microporous structures are disposed on the substrate, and the substrate material is a diamond / aluminum composite material with a thermal conductivity greater than 600 W / m·K. The surface where the composite-sized microporous structures are located is the surface-source blackbody target surface, and the coating is sprayed onto the surface of the composite-sized microporous structures. The composite-sized microporous structures consist of mm-level and μm-level micropores, both arranged in a matrix. Smaller micropores fill the gaps between larger micropores, and every four mm-level micropores surround one μm-level micropore to form an array. Furthermore, at an operating temperature of 230K~400K, the axial temperature difference of the surface-source blackbody target surface is less than 0.05K.

2. The surface-source blackbody target with a multi-scale composite microporous structure according to claim 1, characterized in that, The distance between each μm-level micropore array is the surface pore diameter of the mm-level micropores.

3. The surface-source blackbody target with a multi-scale composite microporous structure according to claim 2, characterized in that, Both the mm-level and μm-level micropore structures are inverted conical in shape.

4. The surface-source blackbody target with a multi-scale composite microporous structure according to claim 2 or 3, characterized in that, Each micropore has a bottom diameter of 1 mm and a cone angle of 36°.

5. The surface-source blackbody target with a multi-scale composite microporous structure according to claim 2 or 3, characterized in that, Each μm-level micropore has a bottom diameter of 50 μm, and the cone angle of the inverted cone ranges from 15° to 25°.

6. The surface-source blackbody target with a multi-scale composite microporous structure according to claim 1, characterized in that, The coating is an ultra-black coating with an emissivity higher than 0.

95.

7. The surface-source blackbody target with a multi-scale composite microporous structure according to claim 1, characterized in that, The effective emissivity of the surface-source blackbody target is greater than 0.

98.

8. The surface-source blackbody target with a multi-scale composite microporous structure according to claim 1, characterized in that, The effective radiation area of ​​the surface source blackbody target is 42mm × 42mm.

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