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CN-121978791-A - Visible near-infrared low-transmission simulated vegetation, mid-infrared high-reflection and microwave high-transmission full-dielectric film system structure

CN121978791ACN 121978791 ACN121978791 ACN 121978791ACN-121978791-A

Abstract

The invention provides a full-dielectric film system structure for simulating vegetation with visible near infrared low transmission, medium infrared high reflection and microwave high transmission. The invention sequentially comprises a visible near infrared simulation vegetation layer, a middle infrared high reflection layer and a substrate layer from top to bottom, wherein the visible near infrared simulation vegetation layer consists of a first dielectric layer to a fourth dielectric layer, is configured to simulate the reflection spectrum characteristics of vegetation in 380-2500 nm wave bands and has low transmission characteristics, the middle infrared high reflection layer consists of a first dielectric layer and a third dielectric layer which are alternately stacked, is configured to form high reflection in the wave bands of 3-14 mu m, and the thickness of the whole film layer is far smaller than the wavelength of microwaves, so that the film system keeps high transmission in the microwave wave bands. According to the invention, by introducing the amorphous InSb material with high loss characteristic in the visible near infrared, the high-precision simulation of vegetation reflectivity spectrum is realized, and meanwhile, the average transmissivity of 1500-2500 nm is reduced to 0.095, so that the simulation of low transmissivity of vegetation in the wave band is realized.

Inventors

  • ZHU HUANZHENG
  • LI QIANG
  • CHAI KE
  • QIU MIN

Assignees

  • 浙江大学

Dates

Publication Date
20260505
Application Date
20260407

Claims (10)

  1. 1. The full-dielectric film system structure with the functions of simulating vegetation in visible near infrared and low transmission, high reflection in mid infrared and high transmission in microwave is characterized in that, The method sequentially comprises the following steps from top to bottom: a visible near infrared simulated vegetation layer consisting of first to fourth dielectric layers configured to simulate vegetation reflectance spectral characteristics at a wavelength band of 380-2500 nm and having low transmission characteristics; A mid-IR high reflection layer composed of a first dielectric layer and a third dielectric layer alternately stacked and configured to form high reflection in a 3-14 μm band, and A substrate layer; the thickness of the whole film layer is far smaller than the wavelength of microwaves, so that the film system keeps high transmission in the microwave band.
  2. 2. The all dielectric film system structure of claim 1, wherein the first dielectric layer is selected from ZnS or HfO 2 , the second dielectric layer is YbF 3 , the third dielectric layer is selected from Ge or Si, and the fourth dielectric layer is selected from amorphous InSb or crystalline Ge 2 Sb 2 Se 4 Te 1 .
  3. 3. The all dielectric film system structure of claim 2, wherein the first dielectric layer is ZnS, the second dielectric layer is YbF 3 , the third dielectric layer is Ge, and the fourth dielectric layer is amorphous InSb.
  4. 4. The all-dielectric film system structure of claim 3, wherein the first dielectric layer has a thickness of 10-550 nm a thickness of 30-100 a nm a thickness of the second dielectric layer, a thickness of 4-600 a nm a thickness of the third dielectric layer, and a thickness of 500-1000 a nm a thickness of the fourth dielectric layer.
  5. 5. The all-dielectric film system structure of claim 4, wherein the visible near-infrared simulated vegetation layer comprises, from top to bottom, a ZnS layer with a thickness of 10 nm, a YbF 3 layer with a thickness of 44 nm, a Ge layer with a thickness of 4 nm, a ZnS layer with a thickness of 75 nm, a YbF 3 layer with a thickness of 87 nm, a ZnS layer with a thickness of 52 nm, a Ge layer with a thickness of 532 nm, a ZnS layer with a thickness of 125 nm, a Ge layer with a thickness of 48 nm, a YbF 3 layer with a thickness of 36 nm, an amorphous InSb layer with a thickness of 995 nm, a Ge layer with a thickness of 7 nm, an amorphous InSb layer with a thickness of 990 nm.
  6. 6. The all-dielectric film system structure according to claim 1, wherein the mid-infrared high reflection layer is formed by alternately stacking a first dielectric layer and a third dielectric layer, and a layer closest to the substrate is the third dielectric layer, which sequentially comprises from top to bottom: A Ge layer of 518 nm a Ge layer of 393 nm a ZnS layer of 30 a nm a ZnS layer of 562 a nm a Ge layer of 590 a nm a ZnS layer of 473 a nm a Ge layer of 220 a nm a ZnS layer of 497 a nm a Ge layer of 271 a nm a ZnS layer of 534 a nm a 516 a nm a ZnS layer of 452 a nm a Ge layer of 39 a nm a ZnS layer of 507 a nm a Ge layer of 517 a nm a.
  7. 7. The all-dielectric film system structure of claim 5 or 6, wherein the overall film system thickness is 8-10 μm.
  8. 8. The all-dielectric film system structure of claim 7, wherein the spectral channels of the film system with the reflectance spectrum in the 380-2500 nm wave band and the standard vegetation reflectance spectrum being more than 90% in accordance meet the standard vegetation spectral characteristic requirement, and the average transmittance in the 1500-2500 nm wave band is lower than 0.1.
  9. 9. The all-dielectric film system structure of claim 7, wherein the film system has an average reflectance of not less than 0.75 in the 3-5 μm band and an average reflectance of not less than 0.6 in the 8-14 μm band.
  10. 10. The all-dielectric film system structure of claim 7, wherein the film system has a transmission of not less than 99% in the microwave band of 5-40 GHz.

Description

Visible near-infrared low-transmission simulated vegetation, mid-infrared high-reflection and microwave high-transmission full-dielectric film system structure Technical Field The invention belongs to the technical field of hyperspectral camouflage, and particularly relates to a full-dielectric film system structure for simulating vegetation with visible near infrared and low transmission, medium infrared and high reflection and microwave and high transmission. Background With the rapid development of modern detection technology, stealth means only aiming at a single wave band is difficult to meet the actual demands. Besides common infrared and microwave detection, hyperspectral imaging technology with spectral resolution of 5-10 nm also forms a significant challenge for traditional camouflage. As the most dominant background for terrestrial targets, green vegetation has a number of significant spectral features that are very easily identified by hyperspectral detection, resulting in exposure of camouflage targets. The main reflection characteristics of vegetation in the visible-near infrared band include (1) a green peak near 550 nm, (2) a red edge 680-780 nm, (3) a near infrared plateau 800-1300 nm, and (4) water absorption peaks 1450 nm and 1950 nm. Therefore, it is increasingly urgent to achieve accurate simulation of vegetation spectra in this band. Some researches have been made on hyperspectral camouflage films of visible-near infrared bands, such as the "natural vegetation imitated visible light-laser-infrared compatible camouflage film" described in chinese patent CN119717096a, chinese patent CN119758501a "thermal infrared low-emissivity green leaf imitated multilayer film and preparation method thereof", chinese patent CN114690278A "multilayer film for hyperspectral-laser stealth", etc. These film systems, while simulating the typical spectral characteristics of vegetation, still have the obvious disadvantage that they only allow the simulation of the reflectivity of vegetation, with a higher transmission in the 1500-2500 nm band, which is not compatible with the low transmission properties of real vegetation in this band, for example, the average transmission of the CN119717096a film system in this band is 83.4%. Because the film system does not realize simulation of low transmittance of 1500-2500 nm vegetation, if the film system is applied to high-reflection substrates such as metal armor, the simulated spectrum curve is destroyed due to superposition of substrate reflection and upper film layer reflection. In addition, to reduce the detectability in the mid-infrared band, the film system needs to have high reflectivity at both the atmospheric windows of 3-5 μm and 8-14 μm to achieve low emissivity. Meanwhile, in order not to influence the communication and detection functions of the equipment, the film system also needs to keep good microwave transmission performance. Therefore, there is an urgent need to develop a novel composite film system structure capable of accurately simulating vegetation spectrum in visible-near infrared, and simultaneously having high reflection in mid-infrared and high transmission in microwave band. Disclosure of Invention In order to solve the defects in the prior art, the invention provides a full-dielectric film system structure which can simulate vegetation spectrum in a visible-near infrared band with low transmission and has the characteristics of high reflection of middle infrared and high transmission of microwaves. The invention sequentially comprises the following steps from top to bottom: a visible near infrared simulated vegetation layer consisting of first to fourth dielectric layers configured to simulate vegetation reflectance spectral characteristics at a wavelength band of 380-2500 nm and having low transmission characteristics; A mid-IR high reflection layer composed of a first dielectric layer and a third dielectric layer alternately stacked and configured to form high reflection in a 3-14 μm band, and A substrate layer; the thickness of the whole film layer is far smaller than the wavelength of microwaves, so that the film system keeps high transmission in the microwave band. Further, the first dielectric layer is selected from ZnS or HfO 2, the second dielectric layer is YbF 3, the third dielectric layer is selected from Ge or Si, and the fourth dielectric layer is selected from amorphous InSb or crystalline Ge 2Sb2Se4Te1. Further, the first dielectric layer is ZnS, the second dielectric layer is YbF 3, the third dielectric layer is Ge, and the fourth dielectric layer is amorphous InSb. Further, the thickness of the first dielectric layer is 10-550 nm, the thickness of the second dielectric layer is 30-100 nm, the thickness of the third dielectric layer is 4-600 nm, and the thickness of the fourth dielectric layer is 500-1000 nm. Further, the visible near infrared simulation vegetation layer comprises a ZnS layer with the thickness of 10 nm, a Y