Novel reversible metal electrodeposition device realizing dynamic regulation of visible-infrared spectral characteristics

Abstract

The application discloses a novel reversible metal electrodeposition device for realizing dynamic regulation of visible light-infrared spectral characteristics, which comprises an infrared conductive unit, an electrochromic unit and a visible light conductive unit, the electrochromic unit is arranged between the infrared conductive unit and the visible light conductive unit; the electrochromic unit comprises a metal deposition layer with adjustable position and form and a gel electrolyte layer. Compared with traditional multi-band compatible regulation devices, the application is no longer limited to single color regulation of visible light and fixed infrared emissivity and the like, the device applies a forward constant deposition voltage and a negative step voltage on the infrared conductive unit and the visible light conductive unit respectively to control the form and position of the metal deposition layer, combines reversible metal electrodeposition, micro-nano structure regulation of infrared radiation characteristics and micro-nano structure regulation of structural color, and realizes dynamic compatible regulation of spectral characteristics of visible light and infrared bands in a true sense.

Description

Technical Field

[0001] This invention relates to the field of visible and infrared dual-band compatible spectral characteristic modulation, specifically to a novel reversible metal electrodeposition device for realizing dynamic modulation of visible-infrared spectral characteristics. Background Technology

[0002] In recent years, camouflage technology targeting a single band has reached a relatively mature stage and plays an important role on the battlefield. However, with the increasing diversification of detection methods and the integrated use of multi-band compatible detection systems, relying solely on single-band camouflage is no longer sufficient to meet operational requirements. Traditional target equipment designed for single-band camouflage faces significant threats; for example, single visible light or infrared camouflage targets are now completely exposed to visible-infrared compatible detectors integrated into small dual-imaging devices. Therefore, research into visible-infrared dual-band compatible camouflage materials or structures is urgently needed. Currently proposed visible-infrared compatible camouflage materials are mainly divided into two categories: infrared camouflage composite coatings with added colored pigments and layered photonic crystal structures combining metals and dielectrics. Typical structures include Al-Fe3O4 core-shell structure pigments, Bi2O3 / ATO composite coatings, Al / polyurethane composite coatings, Al / TiO2 / TiN layer structures, and ZnS / Ag / ZnS sandwich structures. However, the above materials or structures still have many problems caused by integrated and compatible camouflage design, such as limited visible light color, high infrared emissivity of atmospheric windows, and static control—making it difficult to meet the camouflage needs of weapons and equipment across regions, seasons, and all times.

[0003] To address these issues, embedding or integrating smart materials or micro / nano structures with tunable optical properties to develop adaptive visible-infrared compatible camouflage devices is a promising solution. Based on this approach, researchers have developed many devices with multispectral dynamic modulation capabilities. Li Sirui et al. designed a multilayer film structure with tunable infrared absorption rate based on the phase change material germanium-antimony-tellurium (GST) (Li S, Liu K, Long X, et al. Numerical study of infrared broadband multilayer film absorber with tunable structural colors[J]. Optics Communications, 2020, 459:124950.). This structure exhibits an absorption peak with an absorption intensity of approximately 92.06% near 10.9 μm, and an average absorption rate of 65.71% in the 8-13 μm band. Furthermore, by utilizing the different electromagnetic properties of the phase change material GST in its crystalline and amorphous states, the maximum absorption rate can be varied from 92.06% to 9.17%. Furthermore, this structure exhibits a specific reflective color in the visible light band, and the color can be modulated by changing the thickness of the top ZnS film. Li et al. utilized reversible silver electrodeposition to convert the infrared absorption and transmission of an ultrathin nanoscale platinum film into infrared reflection, achieving reversible dynamic control of Δε of approximately 0.7 in the 3-14 μm band (Li M, Liu D, Cheng H, et al. Manipulating metals for adaptive thermal camouflage. Science Advances, 6(22):eaba3494). Based on this, they added a chromium oxide layer between the infrared high-transmittance substrate and the platinum working electrode. As the thickness of the electrodeposited silver film increases, the visible light reflected by the silver film located below the chromium oxide gradually enhances the thin film interference effect, causing the generated structural color to change from a relatively dark color to a brighter color. For the above devices, although their goal is to dynamically modulate the visible-infrared spectral characteristics, they still face some limitations, such as the single modulation color and the low emissivity modulation range. Many proposed devices can only have a fixed structural color (or switch between two colors) based on tunable infrared emissivity, and cannot have a tunable structural color in both high and low infrared emissivity states. Therefore, truly achieving compatible dynamic modulation of spectral characteristics in both visible and infrared bands remains challenging. Summary of the Invention

[0004] The purpose of this invention is to provide a novel reversible metal electrodeposition device that enables dynamic control of visible and infrared spectral characteristics, thereby achieving compatible dynamic control of spectral characteristics in both visible and infrared bands, adapting to different types of background environments, and improving the adaptive camouflage capability of targets.

[0005] The technical solution to achieve the objective of this invention is: a novel reversible metal electrodeposition device with dynamically adjustable visible-infrared spectral characteristics, comprising an infrared conductive unit, an electrochromic unit, and a visible-light conductive unit, wherein the electrochromic unit is sandwiched between the infrared conductive unit and the visible-light conductive unit; the infrared conductive unit includes a first substrate, a dielectric layer disposed on the lower surface of the first substrate, and a first transparent conductive layer formed on the lower surface of the dielectric layer; the electrochromic unit includes a metal deposition layer with adjustable position and shape and a gel electrolyte layer; the visible-light working unit includes a second substrate and a second transparent conductive layer formed on the upper surface of the second substrate and connected to the gel electrolyte layer.

[0006] Furthermore, the position- and morphology-adjustable metal deposition layer serves as a medium for displaying visible light structural colors. By applying a positive constant deposition voltage to the second transparent conductive layer, metal ions in the electrolyte are reduced to metal particles, which are deposited on the first transparent conductive layer and interconnected to form a metal reflective film. This causes the device to exhibit a low infrared emissivity state while simultaneously displaying a structural color related to the thickness of the dielectric layer. Subsequently, a dissolution voltage is applied, and the deposited metal particles are gradually oxidized to metal ions, the metal film dissolves, and the device returns to its initial high infrared emissivity state, while the visible light displays a transparent color. When a negative step voltage is applied to the second transparent conductive layer, metal ions are reduced to metal particles and deposited on the second transparent conductive layer, forming dispersed spherical nanoparticles. By controlling the voltage application time, the diameter of the spherical nanoparticles can be adjusted, allowing the device to exhibit various variable structural colors in the high infrared emissivity state. Then, a dissolution voltage is applied, and the deposited metal nanoparticles are gradually oxidized to metal ions and dissolved in the electrolyte. At this time, the infrared state of the device remains unchanged, while the visible light effect returns from a bright structural color to the initial transparent color.

[0007] Furthermore, the thickness of the dielectric layer is 80nm to 300nm, and the material is selected from one of the following: silicon carbide, titanium dioxide, aluminum oxide, and gallium arsenide.

[0008] Furthermore, the positive constant deposition voltage V1 = 2.2~2.8V, and the application time t1 = 20~30s; the negative step voltage V2 = -4.4V~-2.6V, t2 = 20~80ms; V3 = -1.6V, t3 = 0~80s.

[0009] Furthermore, the infrared low emissivity state is defined as an average infrared emissivity ≤ 0.25, and the infrared high emissivity state is defined as an average infrared emissivity ≥ 0.55.

[0010] Furthermore, the gel electrolyte layer has a transmittance of ≥0.8 in the visible light band and an absorption rate of ≥0.7 in the infrared band. The gel electrolyte provides the metal cations required for electrodeposition, has a thickness of ≥250μm, and contains silver nitrate, wherein silver ions serve as the metal ions for electrodeposition / dissolution.

[0011] Furthermore, the first transparent conductive layer serves as the counter electrode, with a transmittance ≥0.7 in both the visible and infrared bands. The material is selected from the group consisting of platinum, gold, and combinations thereof, and the thickness of the first transparent conductive layer is 1–5 nm.

[0012] Furthermore, the second transparent conductive layer serves as the working electrode, with a transmittance ≥0.7 in the visible light band. The material used is indium tin oxide, and the thickness of the second transparent conductive layer is 0.2–2 mm.

[0013] Furthermore, the first substrate has a transmittance of ≥0.8 in both the visible and infrared bands, and the material is selected from the group consisting of barium fluoride, calcium fluoride, lithium fluoride, and combinations thereof, with a thickness of 0.2 to 1.2 mm.

[0014] Furthermore, the second substrate has a transmittance of ≥0.8 in the visible light band, and the material is selected from the group consisting of glass, barium fluoride, calcium fluoride, lithium fluoride, and combinations thereof, with a thickness of 0.2 to 2 mm.

[0015] Compared with the prior art, the gains of the present invention are as follows: (1) The present invention controls the position and shape of the metal deposition layer by applying two different voltages to the second transparent conductive layer, and successfully achieves a wide range of infrared emissivity changes. Regardless of whether the device is in a high infrared emissivity state or a low infrared emissivity state, it can exhibit a variety of dynamic and vivid structural colors. The device truly achieves compatible dynamic control of the spectral characteristics of the visible light and infrared bands; (2) The present invention introduces a dielectric layer in the infrared working unit. When a positive constant voltage is applied, silver is deposited on the first transparent conductive layer to form a metal high reflectivity film, so that the device exhibits a low emission state in the infrared band. At the same time, the deposited silver film and the upper dielectric layer excite the FP resonance effect, which causes the device to exhibit a specific structural color related to the thickness of the dielectric layer in the visible light band; (3) The present invention applies a negative step voltage to deposit silver particles on the second transparent conductive layer to form dispersed spherical nanoparticles and excites the local plasmon resonance (LSPR) effect to display structural colors. By controlling the voltage application time, the diameter of the spherical nanoparticles can be adjusted, thereby controlling its LSPR characteristics, so that the device can exhibit a variety of variable structural colors in the infrared high emissivity state. (4) The dielectric layer selected in this invention is very suitable in terms of material selection. Under the action of positive constant voltage, even within a small range of dielectric layer thickness variation, the device can exhibit a rich range of colors across the entire visible light spectrum; (5) By controlling the type and direction of the applied voltage, this invention achieves a perfect combination of reversible metal electrodeposition and electromagnetic effects of micro-nano structures; (6) This invention uses an ultrathin noble metal film as the first transparent conductive layer, which has high transmittance for incident light in both visible and infrared bands, providing a basic condition for achieving a wide range of tunability of infrared emissivity. Attached Figure Description

[0016] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof.

[0017] Figure 1 This is a schematic diagram of the device structure under two different deposition voltages in an embodiment of the present invention.

[0018] Figure 2 This is the correspondence between the silicon carbide thickness variation and the calculated structural color when silver is deposited on the platinum counter electrode in an embodiment of the present invention.

[0019] Figure 3 This describes the real-time infrared spectral characteristics of a novel reversible metal electrodeposition device under a positive constant voltage in an embodiment of the present invention.

[0020] Figure 4 This is an example of the real-time visible light color change of a novel reversible metal electrodeposition device when a positive constant voltage is applied in an embodiment of the present invention.

[0021] Figure 5 This describes the real-time infrared spectral characteristics of a novel reversible metal electrodeposition device when a negative step voltage is applied in an embodiment of the present invention.

[0022] Figure 6 This is a comparison of the real-time infrared absorption spectra of the novel reversible metal electrodeposition device under the applied negative step voltage and in its initial state in an embodiment of the present invention.

[0023] Figure 7 This is an example of the real-time visible light color change of a novel reversible metal electrodeposition device when a negative step voltage is applied in an embodiment of the present invention.

[0024] Figure 8 This describes the tunable range of infrared emissivity of the novel reversible metal electrodeposition device when two different types of voltages are applied in embodiments of the present invention. Detailed Implementation

[0025] The present invention will be further illustrated below with specific embodiments. However, it should be understood that these embodiments are merely for more detailed and specific illustration and should not be construed as limiting the present invention in any way.

[0026] The present invention relates to a novel reversible metal electrodeposition device with dynamically modulated visible-infrared spectral characteristics, comprising an infrared conductive unit, an electrochromic unit, and a visible light conductive unit, wherein the electrochromic unit is sandwiched between the infrared conductive unit and the visible light conductive unit.

[0027] The infrared conductive unit includes a first substrate, a dielectric layer disposed on the lower surface of the first substrate, and a first transparent conductive layer formed on the lower surface of the dielectric layer; the electrochromic unit includes a metal deposition layer with adjustable position and shape and a gel electrolyte layer; the visible light working unit includes a second substrate and a second transparent conductive layer formed on the upper surface of the second substrate and connected to the gel electrolyte layer.

[0028] The first substrate is mainly used to transmit incident light in the visible-infrared band and to support the first transparent conductive layer. It has ultra-high transmittance in both the visible and infrared bands. The materials are selected from the group consisting of barium fluoride, calcium fluoride, lithium fluoride and combinations thereof, and the thickness is 0.2 to 1.2 mm.

[0029] The dielectric layer is mainly used to form an FP cavity with the deposited silver film to display structural color. The thickness of the dielectric layer is 80nm to 300nm, and the material is selected from one of the following: silicon carbide, titanium dioxide, aluminum oxide, and gallium arsenide.

[0030] The first transparent conductive layer has a thickness of 1-5 nm and is mainly used for conducting and transmitting incident light in the visible-infrared band. It has high transmittance in both the visible and infrared bands. The materials are selected from the group consisting of platinum, gold and combinations thereof.

[0031] The positional and morphologically adjustable metal deposition layer serves as a medium for displaying visible light structural colors. By applying a positive constant deposition voltage to the second transparent conductive layer, metal ions in the electrolyte are reduced to metal particles, which are deposited on the first transparent conductive layer and interconnect to form a metal reflective film. This causes the device to exhibit a high infrared reflectivity (low emissivity) state while simultaneously displaying a specific structural color related to the dielectric layer thickness. Subsequently, a dissolution voltage is applied, and the deposited metal particles are gradually oxidized into metal ions, the metal film dissolves, and the device returns to its initial high infrared emissivity state, while the visible light displays a transparent color. When a negative step voltage is applied to the second transparent conductive layer, the metal ions are reduced to metal particles and deposited on the second transparent conductive layer, forming dispersed spherical nanoparticles. By controlling the voltage application time, the diameter of the spherical nanoparticles can be adjusted, allowing the device to exhibit various variable structural colors in the high infrared emissivity state. Then, a dissolution voltage is applied, and the deposited metal nanoparticles are gradually oxidized into metal ions and dissolved into the electrolyte. At this point, the infrared state of the device remains unchanged, while the visible light effect reverts from a vibrant structural color to the initial transparent color.

[0032] The forward constant deposition voltage is mainly used for depositing silver thin films. The voltage is V1 = 2.2 to 2.8V and the application time is t1 = 20 to 30s.

[0033] The negative step voltage is mainly used for depositing dispersed spherical silver nanoparticles. The voltage magnitude and application time are: V2 = -4.4V to -2.6V, t2 = 20 to 80ms; V3 = -1.6V, t3 = 0 to 80s.

[0034] The gel electrolyte layer primarily serves to provide electrodeposited silver ions, transmit incident light in the visible light band, and absorb incident light in the infrared band. The gel electrolyte layer exhibits high transmittance in the visible light band and high absorption characteristics in the infrared band. When the device is in its initial state or under a negative step voltage, the incident infrared light transmitted from the first substrate, dielectric layer, and first transparent conductive layer is absorbed by the gel electrolyte layer, resulting in a high infrared emissivity for the entire device. The gel electrolyte contains silver nitrate, where silver ions act as electrodeposited / dissolved metal cations.

[0035] The second transparent conductive layer is mainly used for conducting and transmitting incident light in the visible light band. It has high transmittance in the visible light band. The material selected is indium tin oxide, and the thickness of the second transparent conductive layer is 0.2 to 2 mm.

[0036] The second substrate is mainly used to transmit incident light in the visible light band and to support the second transparent conductive layer. It has ultra-high transmittance in the visible light band. The materials are selected from the group consisting of glass, barium fluoride, calcium fluoride, lithium fluoride and combinations thereof, and the thickness is 0.2 to 2 mm.

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0038] Example

[0039] The first substrate is barium fluoride with a thickness of 1 mm; the dielectric layer is silicon carbide with a thickness of 180 nm; the first transparent conductive layer is platinum with a thickness of 5 nm; the gel electrolyte layer is prepared by adding 0.5 mM silver nitrate, 2.5 mM tetrabutylammonium bromide, 0.1 mM copper chloride, and 10 wt% polyvinyl butyral as the main polymer in 10 ml dimethyl sulfoxide, with a thickness of 450 μm; the second transparent conductive layer is indium tin oxide with a thickness of 0.3 mm; the second substrate is glass with a thickness of 1 mm; the positive constant deposition voltage is V1 = 2.5 V, and the application time is t1 = 20 s; the negative step voltage and application time are: V2 = -4 V, t2 = 20 ms; V3 = -1.6 V, t3 = 0–20 s. See also Figure 1 When the device is in its initial state (without silver deposition), it is transparent in the visible light band. At the same time, because the incident light in the infrared band is absorbed by the gel electrolyte layer, the device exhibits a high infrared emissivity.

[0040] First, the finite-difference time-domain (FDTD) method was used to calculate the correspondence between the visible light reflectance characteristics of the device and the silicon carbide thickness and structural color when silver particles are deposited on a platinum electrode to form a metallic reflective thin film. (See [reference needed]). Figure 2 When the silicon carbide thickness varies from 100 nm to 180 nm, i.e., within a thickness variation range of 80 nm, the device can achieve a full color gamut spanning the entire visible spectrum (from violet to red). Subsequently, the device is fabricated, and its real-time visible-infrared spectral characteristics under a positive constant voltage are measured using an infrared spectrometer. See [link to relevant documentation]. Figure 3 and Figure 4In the infrared band, silver particles are completely electrodeposited on the platinum counter electrode and interconnected to form a metallic reflective film, resulting in a high level of infrared reflectivity, especially in the 3-10 μm band. Calculations show that the device has an average reflectivity of 0.879 (average emissivity 0.121) in the 3-14 μm band. In the visible light band, simulation results show that when the SiC layer thickness is 180 nm, the device should exhibit a purple hue. Figure 2 Actual test results show that the device does indeed exhibit a purple hue, proving the consistency between the simulation results and the experimental results.

[0041] When silver particles are deposited downwards onto the indium tin oxide working electrode to form spherical nanoparticles, i.e., when a negative step voltage is applied to the device, the real-time visible-infrared spectral characteristics of the device are shown in [reference needed]. Figure 5 and Figure 7 The device exhibits high and stable infrared absorption across the entire infrared band (average emissivity of 0.702). The average reflectivity of approximately 0.3 is due to the presence of a silicon carbide dielectric layer and a platinum layer on the barium fluoride substrate on the upper side of the device, causing a small portion of infrared light to be reflected by these two layers before reaching the gel electrolyte layer. Furthermore, after applying step voltages V2 = -4V, t2 = 20ms, and V3 = -1.6V, t3 = 20s, the infrared absorption characteristics of the device remained essentially unchanged compared to its initial state; the device consistently maintained a high infrared emissivity. (See [link to relevant documentation]). Figure 6 Meanwhile, in the visible light band, the device can exhibit a reversible color transition from transparent to red to blue to dark blue within 20 seconds of applying a growth voltage V3.

[0042] In summary, for this device, when a negative step voltage is applied, the device can achieve a high emissivity state in the infrared band, and simultaneously exhibit multiple dynamic structural colors based on the LSPR effect of noble metal nanoparticles, depending on the duration of the growth voltage V3 application. Conversely, when a positive constant deposition voltage is applied, the device can achieve a low emissivity state in the infrared band, and simultaneously exhibit specific vibrant structural colors based on the FP resonance effect of the silicon carbide dielectric layer (these colors can be adjusted according to the duration of the deposition voltage V3 application). Figure 2 (The calculation results are pre-selected). Δε is obtained after calculation. 3-14μm ≥0.583, Δε 3-5μm ≥0.643, Δε 8-14μm ≥0.562, such as Figure 8 As shown, the proposed device not only has a large tunability of infrared emissivity, but also exhibits vivid structural colors regardless of whether the device is in a high or low infrared emissivity state, successfully realizing dynamic control of visible-infrared dual-band compatible spectral characteristics.

Claims

1. A novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics, characterized in that, It includes an infrared conductive unit, an electrochromic unit, and a visible light conductive unit, wherein the electrochromic unit is sandwiched between the infrared conductive unit and the visible light conductive unit; the infrared conductive unit includes a first substrate, a dielectric layer disposed on the lower surface of the first substrate, and a first transparent conductive layer formed on the lower surface of the dielectric layer. The electrochromic unit includes a metal deposition layer with adjustable position and shape and a gel electrolyte layer; the visible light working unit includes a second substrate and a second transparent conductive layer formed on the upper surface of the second substrate and connected to the gel electrolyte layer. The position and shape-adjustable metal deposition layer serves as a medium for displaying visible light structural colors. By applying a positive constant deposition voltage to the second transparent conductive layer, metal ions in the electrolyte are reduced to metal particles, which are deposited on the first transparent conductive layer and interconnect to form a metal reflective film. This causes the device to exhibit a low infrared emissivity state while simultaneously displaying a structural color related to the thickness of the dielectric layer. Subsequently, a dissolution voltage is applied, and the deposited metal particles are gradually oxidized to metal ions, dissolving the metal film and restoring the device to its initial high infrared emissivity state, while the visible light displays a transparent color. When a negative step voltage is applied to the second transparent conductive layer, metal ions are reduced to metal particles and deposited on the second transparent conductive layer, forming dispersed spherical nanoparticles. By controlling the voltage application time, the diameter of the spherical nanoparticles can be adjusted, allowing the device to exhibit various variable structural colors in the high infrared emissivity state. Then, a dissolution voltage is applied, and the deposited metal nanoparticles are gradually oxidized to metal ions and dissolved in the electrolyte. At this point, the infrared state of the device remains unchanged, while the visible light effect returns from a bright structural color to the initial transparent color.

2. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The thickness of the dielectric layer is 80nm~300nm, and the material is selected from one of the following: silicon carbide, titanium dioxide, aluminum oxide, gallium arsenide.

3. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The positive constant deposition voltage V1 = 2.2~2.8V, applied for t1 = 20~30s; the negative step voltage V2 = -4.4V~-2.6V, t2 = 20~80ms; V3 = -1.6V, t3 = 0~80s.

4. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The infrared low emissivity state is defined as an average infrared emissivity ≤ 0.25, and the infrared high emissivity state is defined as an average infrared emissivity ≥ 0.

55.

5. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The gel electrolyte layer has a transmittance of ≥0.8 in the visible light band and an absorption rate of ≥0.7 in the infrared band. The gel electrolyte provides the metal cations required for electrodeposition and has a thickness of ≥250μm. The gel electrolyte layer contains silver nitrate, wherein silver ions serve as the metal ions for electrodeposition / dissolution.

6. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The first transparent conductive layer serves as the counter electrode, with a transmittance of ≥0.7 in both the visible and infrared bands. The material is selected from the group consisting of platinum, gold, and combinations thereof, and the thickness of the first transparent conductive layer is 1~5 nm.

7. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The second transparent conductive layer serves as the working electrode, with a transmittance ≥0.7 in the visible light band. The material used is indium tin oxide, and the thickness of the second transparent conductive layer is 0.2~2mm.

8. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The first substrate has a transmittance of ≥0.8 in both the visible and infrared bands, and the material is selected from the group consisting of barium fluoride, calcium fluoride, lithium fluoride and combinations thereof, with a thickness of 0.2~1.2 mm.

9. The novel reversible metal electrodeposition device for dynamically controlling visible-infrared spectral characteristics according to claim 1, characterized in that, The second substrate has a transmittance of ≥0.8 in the visible light band, and the material is selected from the group consisting of glass, barium fluoride, calcium fluoride, lithium fluoride and combinations thereof, with a thickness of 0.2~2mm.

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