A light extinction super black flexible film for spacecraft
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-28
- Publication Date
- 2026-08-11
Smart Images
Figure CN122546359A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of aerospace optical functional materials technology, specifically relating to an ultra-black flexible film for spacecraft, which is particularly suitable for stray light suppression in high-precision optical systems such as space telescopes, star sensors, and deep space exploration cameras. Background Technology
[0002] Currently, spacecraft optical payloads are facing increasingly higher requirements for detection accuracy, from early meter-level resolution to today's sub-meter and even centimeter-level resolution, while also posing unprecedented challenges to signal-to-noise ratio, positioning accuracy, and long-term reliability. Against this backdrop, suppressing stray light is crucial for improving the high resolution and high sensitivity of spacecraft optical systems, becoming a core driving force for the development of space optics technology.
[0003] Traditional methods for eliminating stray light include techniques such as mask design, aperture optimization, and surface treatment. However, these methods all face limitations to varying degrees in high-precision optical systems. Mask and aperture design are the most direct methods in traditional stray light suppression. Masks physically block strong external light sources from directly entering the optical system, while apertures restrict the area through which the light beam can pass. However, with the increasing complexity of optical systems, the design difficulty and manufacturing cost of mask and aperture have also increased significantly. Furthermore, assembly precision and material properties often fail to meet requirements, resulting in less than ideal stray light suppression effects.
[0004] Surface treatment technology is another important way to suppress stray light. However, traditional surface treatment methods have significant shortcomings in terms of absorptivity, low volatility, antistatic properties, and flexibility. Taking Z306 organic matte black paint as an example, its solar absorptivity (αs) is only about 0.93, which cannot achieve higher absorption of sunlight. At the same time, its adhesion is relatively poor, and it does not have antistatic properties, which cannot meet the long-term service requirements of high-reliability spacecraft. Although the black anodizing surface treatment method has a high absorptivity of about 96%, solvent impurities may still remain in the film layer, which can cause uncontrollable outgassing in the space environment. In addition, its poor conductivity can easily cause electrostatic discharge, threatening system safety and imaging.
[0005] Micro-nano structure surface treatment is a novel stray light suppression technology that has emerged in recent years. By constructing periodic micro-nano structures and designing material systems on surfaces, light scattering and absorption are increased, thereby improving stray light suppression. However, traditional micro-nano structure fabrication for ultra-black products mainly focuses on solid material surfaces, requiring high material properties and involving complex fabrication processes, making large-area fabrication impossible. For example, Francesco De Nicola et al., in their paper "Moth-eye effect in hierarchical carbon nanotube anti-re...", discussed this issue. The paper "Ecological Coatings" describes a method for depositing single-walled carbon nanotube films onto a silicon substrate using solution processing and dry transfer techniques. This creates an ultra-black product with a moth-eye-like structure, achieving anti-reflection and strong absorption effects. However, this micro / nano structure exhibits a disordered and random distribution, resulting in weak adhesion to the substrate. Furthermore, solvent residue remains during the fabrication process, failing to meet the low-volatile pollution requirements of high-precision optical systems. Additionally, it is limited to solid silicon surfaces, making direct application to flexible substrates difficult, and its implementation on curved surfaces and complex optical structures is challenging, leading to low operational reliability. Summary of the Invention
[0006] To address the aforementioned technical problems and suppress the impact of stray light on high-performance spacecraft optical systems, the present invention aims to provide a matting ultra-black flexible thin film for spacecraft and its preparation method. Through microstructure and material design, the present invention constructs a "gradient aperture micro / nano structure layer + gradient functional carbon layer + AZO antistatic layer" on the surface of carburized polyimide, achieving large-area fabrication of a high-absorption, low-volatility, antistatic, and angle-independent flexible matting ultra-black thin film.
[0007] The matte ultra-black flexible film of the present invention for spacecraft consists of, from bottom to top, a carburized polyimide flexible substrate, a gradient pore size micro / nano structure layer, a gradient functional carbon layer, and an AZO antistatic layer. The gradient pore size micro / nano structure layer is a periodic array of pores directly constructed on the surface of the carburized polyimide substrate using nanoimprinting technology, with the pore size increasing linearly from the substrate to the surface.
[0008] The objective of this invention is achieved through the following technical solution: In a first aspect, the present invention provides a matte ultra-black flexible film for spacecraft, comprising, from bottom to top, a carburized polyimide flexible substrate; Gradient-aperture micro / nano structure layers are directly constructed on the surface of a carburized polyimide flexible substrate; Gradient functionalized carbon layers, including an oxygen-doped bottom layer, a nitrogen-doped middle layer, and a high sp2 surface layer. 2 carbon; The outermost layer is an AZO antistatic layer, which is aluminum-doped zinc oxide.
[0009] As some specific embodiments of the present invention, the thickness of the carburized polyimide film flexible substrate is 25 μm to 100 μm.
[0010] As some specific embodiments of the present invention, the gradient aperture micro / nano structure layer is composed of a periodic pore array, with the pore size increasing linearly from the substrate to the surface. The pore size d1 at the substrate is 200~600 nm, the pore size d2 at the surface is 600~900 nm, the pore depth h is 1000~2000 nm, the period P is 800~1600 nm, and d2 / P < 1.
[0011] As some specific embodiments of the present invention, in the gradient aperture micro / nano structure layer, the gradient rate of the aperture is 0.1~1nm / nm.
[0012] As some specific embodiments of the present invention, the ratio of the period to the pore depth of the gradient aperture micro / nano structure layer is 0.4 to 0.8.
[0013] As some specific embodiments of the present invention, the gradient pore size micro / nano structure layer is prepared on a carburized polyimide flexible substrate using nanoimprinting technology.
[0014] In some specific embodiments of the present invention, in the gradient functional carbon layer, the thickness of the bottom oxygen-doped carbon layer is 20-80 nm, the thickness of the middle nitrogen-doped carbon layer is 20-60 nm, and the thickness of the surface high sp layer is... 2 The thickness of the carbon layer is 10~40 nm.
[0015] As some specific embodiments of the present invention, in the gradient functional carbon layer, the oxygen content of the bottom oxygen-doped carbon is 5~10 at; and the nitrogen content of the middle nitrogen-doped carbon is 5~15 at.
[0016] As some specific embodiments of the present invention, the thickness of the AZO antistatic layer is 10~30 nm.
[0017] As some specific embodiments of the present invention, the gradient functional carbon layer and the AZO antistatic layer are prepared by magnetron sputtering technology.
[0018] Furthermore, when fabricating the gradient functional carbon layer and the AZO antistatic layer using the aforementioned magnetron sputtering technology, under a bias voltage of -20 V to -50 V, oxygen-doped carbon (bottom layer), nitrogen-doped carbon (middle layer), and high sp layer are deposited sequentially. 2 Carbon (surface layer) and AZO layer; the magnetron sputtering deposition temperature is 50℃~150℃.
[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention prepares a matte ultra-black flexible film for spacecraft. Through the synergistic design of gradient aperture micro-nano structure and gradient functional carbon layer, while maintaining the excellent properties of carburized polyimide matrix, it significantly enhances the broadband absorption capability of the solar main band of 250~2500 nm. The solar absorptivity αs can reach 0.994, which is 10% higher than that of traditional Z306 matte black paint.
[0020] (2) Through bottom oxygen-doped carbon, middle nitrogen-doped carbon and surface high sp 2 The gradient functional integration of carbon enables interfacial stress buffering and electrostatic dissipation (surface resistivity ≤10). 7 The film combines Ω with high absorption performance, and further enhances low volatility, antistatic properties, and space environment stability with an outer composite AZO antistatic layer. The film's manufacturing process is simple, with controllable parameters, and is easy to mass-produce. It is highly operable and suitable for various aerospace applications such as space telescope shields, deployable optical cabins, and star sensor inner walls, achieving efficient and reliable stray light suppression.
[0021] (3) The thin film prepared by this invention achieves an average reflectivity of ≤0.6% in the wavelength range of 250~2500 nm, and the reflectivity fluctuation is less than 2% in the incident angle range of 0°~60°, with no dependence on the incident angle; at the same time, it has the ability to dissipate static electricity (surface resistivity ≤10). 7 It features low volatility (total mass loss TML ≤ 0.4%, condensable volatile matter CVCM ≤ 0.04%) and excellent adaptability to the space environment. This thin film can be fabricated in large areas by roll-to-roll and can be bonded to flexible aerospace structural components such as complex curved surface sunshades and foldable optical cabins. It is suitable for stray light suppression in high-precision optical systems such as space telescopes, star sensors, and deep space exploration cameras. Attached Figure Description
[0022] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic diagram of the structure of the matte ultra-black flexible film used in spacecraft according to the present invention; Among them, 1 is a carburized polyimide flexible matrix, 2 is a gradient pore size micro / nano structure layer, and 3 is a gradient functional carbon layer (divided into a bottom layer of oxygen-doped carbon, a middle layer of nitrogen-doped carbon, and a surface layer of high sp). 2 Carbon), 4 is the AZO antistatic layer; Figure 2 The reflectance spectrum of the thin film prepared in Example 1 in the range of 250 nm to 2500 nm is shown. Detailed Implementation
[0023] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.
[0024] like Figure 1 The diagram shows the structure of the matte ultra-black flexible thin film for spacecraft according to the present invention; wherein 1 is a carburized polyimide flexible substrate, 2 is a gradient pore size micro / nano structure layer, and 3 is a gradient functional carbon layer (divided into a bottom oxygen-doped carbon layer, a middle nitrogen-doped carbon layer, and a surface high sp layer). 2 Carbon), 4 is the AZO antistatic layer.
[0025] The matte ultra-black flexible film for spacecraft in this invention comprises a gradient-pore-size micro / nano structure layer 2 constructed on one side of a carburized polyimide flexible substrate 1, with the other side optionally serving as an adhesive surface; a gradient functional carbon layer 3 (including an oxygen-doped bottom layer, a nitrogen-doped middle layer, and a high-sp surface layer) is sequentially deposited on the surface of the micro / nano structure layer 2. 2 Carbon) and AZO antistatic layer 4.
[0026] Example 1 Using a 50 μm thick carburized polyimide substrate, a gradient-pore micro / nanostructure was fabricated on its surface using nanoimprinting technology: pore size d1 = 300 nm at the substrate, pore size d2 = 860 nm at the surface, pore depth h = 1400 nm, period P = 1000 nm, and pore size gradient rate approximately 0.2 nm / nm; subsequently, the sample was transferred to a magnetron sputtering apparatus for Ar... + Pre-sputtering treatment for 2 min (power 65 W, gas pressure 0.5 Pa), deposition temperature controlled at 85℃; switching to carbon target, under -35 V bias, sequentially depositing 50 nm oxygen-doped carbon in an Ar / O2=95 / 5 atmosphere, with an oxygen content of approximately 5~10 at%; depositing 30 nm nitrogen-doped carbon in an Ar / N2=90 / 10 atmosphere, with a nitrogen content of approximately 10~15 at%; and depositing 25 nm high-sp... 2 Carbon was then transferred to the AZO target site (Al doping amount 2 at%), and a 20 nm AZO antistatic layer was deposited under an Ar / O2=92 / 8 atmosphere at a bias voltage of -30 V.
[0027] The prepared matte ultra-black flexible film was subjected to the following tests: the solar absorptivity of the film was tested according to GJB 2502.2 "Test Methods for Thermal Control Coatings of Spacecraft Part 2: Solar Absorption Ratio Test"; the surface resistivity of the film was tested according to GB1410 "Test Methods for Volume Resistivity and Surface Resistivity of Solid Insulating Materials"; and the gas evolution performance of the film was tested according to QJ558 "Test Methods for Volatilization Performance of Materials in Vacuum". All other examples and comparative examples were tested according to the above standards.
[0028] (1) Optical performance test: The average reflectance of the thin film in the wavelength range of 250~2500 nm is 0.6%, and the test curve is as follows. Figure 2 As shown, the solar absorptivity of this thin film is 0.994; (2) Electrical performance test: The surface resistivity of the thin film is 5.6 × 10⁻⁶. 6 Ω; (3) Vacuum exhaust performance test: TML=0.38%, CVCM=0.036%.
[0029] Example 2 The only difference between this embodiment and Embodiment 1 is that the period P of the gradient aperture micro / nano structure is 1000 nm and the pore depth h is 1500 nm (period to pore depth ratio P / h = 0.67). All other steps are performed in accordance with Embodiment 1.
[0030] The prepared matte ultra-black flexible film was tested and found to have an average reflectance of 0.8% in the 250–2500 nm range, a solar absorptivity of 0.992, and a surface resistivity of 6.2 × 10⁻⁶. 6 Ω, TML=0.35%, CVCM=0.035%.
[0031] Example 3 The only difference between this embodiment and Embodiment 1 is that the surface layer of the gradient functionalized carbon layer has a high sp 2 The carbon thickness was 35 nm, and the remaining steps were performed in accordance with Example 1.
[0032] The prepared matte ultra-black flexible film was tested and found to have an average reflectance of 0.8% in the 250–2500 nm range, a solar absorptivity of 0.992, and a surface resistivity of 5.2 × 10⁻⁶. 6 Ω, TML=0.31%, CVCM=0.038%.
[0033] Example 4 The only difference between this embodiment and Embodiment 1 is that a 25μm flexible carburized polyimide film is used as the substrate; all other steps are performed in accordance with Embodiment 1.
[0034] The prepared matte ultra-black flexible film was tested and found to have an average reflectance of 0.6% in the 250–2500 nm range, a solar absorptivity of 0.992, and a surface resistivity of 5.2 × 10⁻⁶. 6 Ω, TML=0.28%, CVCM=0.030%.
[0035] Example 5 The only difference between this embodiment and Embodiment 1 is that the thickness of the AZO antistatic layer is 15 nm; all other steps are performed in accordance with Embodiment 1.
[0036] The prepared matte ultra-black flexible film was tested and found to have an average reflectance of 0.7% in the 250–2500 nm range, a solar absorptivity of 0.993, and a surface resistivity of 4.2 × 10⁻⁶. 6 Ω, TML=0.28%, CVCM=0.030%.
[0037] Example 6 The only difference between this embodiment and Embodiment 1 is that the oxygen content of the bottom oxygen-doped carbon in the gradient functional carbon layer is 5 at% (thickness 50 nm), and the nitrogen content of the middle nitrogen-doped carbon is 8 at% (thickness 30 nm). All other steps are performed in accordance with Embodiment 1.
[0038] The prepared matte ultra-black flexible film was tested and found to have an average reflectance of 0.8% in the 250–2500 nm range, a solar absorptivity of 0.992, and a surface resistivity of 5.8 × 10⁻⁶. 6 Ω, TML=0.33%, CVCM=0.029%.
[0039] Comparative Example 1 Tests were conducted on untreated flexible carburized polyimide films: the average reflectance at 250~2500 nm was 10%, the solar absorptivity was 0.900, TML=0.67%, CVCM=0.057%, and the surface did not have antistatic properties.
[0040] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that a gradient pore size micro / nano structure layer was not constructed on the surface of the carburized polyimide matrix; all other steps were performed in accordance with Example 1.
[0041] The thin film prepared in Comparative Example 2 was tested and found to have an average reflectance of 7% in the 250–2500 nm range, a solar absorptivity of 0.930, and a surface resistivity of 5.3 × 10⁻⁶. 6 Ω, TML=0.35%, CVCM=0.031%.
[0042] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.
Claims
1. A light extinction super black flexible film for a spacecraft, characterized by, Including, from bottom to top, the following: a carburized polyimide flexible matrix; Gradient-pore-size micro / nano structure layers are directly constructed on the surface of a carburized polyimide flexible substrate; Gradient functional carbon layer, including bottom layer oxygen-doped carbon, middle layer nitrogen-doped carbon and surface layer high-sp 2 Carbon; The outermost layer is an AZO antistatic layer, which is aluminum-doped zinc oxide.
2. The matt ultra-black flexible film according to claim 1, wherein, The thickness of the carburized polyimide film flexible substrate is 25 μm to 100 μm.
3. The matt ultra-black flexible film according to claim 1, wherein, The gradient aperture micro / nano structure layer is composed of a periodic pore array, with the pore size increasing linearly from the substrate to the surface. The pore size d1 at the substrate is 200~600 nm, the pore size d2 at the surface is 600~900 nm, the pore depth h is 1000~2000 nm, the period P is 800~1600 nm, and d2 / P < 1.
4. The matt ultra-black flexible film according to claim 3, wherein, In the gradient aperture micro / nano structure layer, the pore size gradient rate is 0.1~1nm / nm; And / or, the ratio of the period to the pore depth of the gradient aperture micro / nanostructure layer is 0.4 to 0.
8.
5. The matt ultra-black flexible film according to claim 1, wherein The gradient pore size micro / nano structure layer was prepared on a carburized polyimide flexible substrate using nanoimprinting technology.
6. The matt ultra-black flexible film according to claim 1, wherein In the gradient functional carbon layer, the thickness of the bottom oxygen-doped carbon layer is 20-80 nm, the thickness of the middle nitrogen-doped carbon layer is 20-60 nm, and the thickness of the surface high sp layer is... 2 The thickness of the carbon layer is 10~40 nm.
7. The matt ultra-black flexible film according to claim 1, wherein In the gradient functional carbon layer, the oxygen content of the bottom oxygen-doped carbon is 5~10 at; and the nitrogen content of the middle nitrogen-doped carbon is 5~15 at.
8. The matt ultra-black flexible film according to claim 1, wherein, The thickness of the AZO antistatic layer is 10~30 nm.
9. The matt ultra-black flexible film according to claim 1, wherein, The gradient functional carbon layer and the AZO antistatic layer were prepared using magnetron sputtering technology.
10. The matt ultra-black flexible film according to claim 9, wherein, When fabricating graded functional carbon layers and AZO antistatic layers using the aforementioned magnetron sputtering technique, oxygen-doped carbon, nitrogen-doped carbon, and high-sp are sequentially deposited under a bias voltage of -20 V to -50 V. 2 Carbon and AZO layer; the magnetron sputtering deposition temperature is 50℃~150℃.