A film structure for laser transmission, long-wave infrared cutoff, and radar electromagnetic wave shielding

Abstract

This invention provides a film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding, comprising a multispectral zinc sulfide substrate, six thin films disposed on the front side of the multispectral zinc sulfide substrate, and three thin films disposed on the back side of the multispectral zinc sulfide substrate. The six thin films on the front side, from the inside out, are: a first NiCr film, a second Au film, a third Ta2O5 film, a fourth SiO2 film, a fifth Ta2O5 film, and a sixth SiO2 film. The three thin films on the back side, from the inside out, are: a first ITO film, a second Ta2O5 film, and a third SiO2 film. The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided by this invention has a transmittance greater than 86% for a 1.064μm laser wavelength tested at 0°, an average design value of less than 10% transmittance in the 7.7μm~11μm long-wave infrared band, and a highly efficient radar wave shielding function.

Description

Technical Field

[0001] This invention belongs to the field of optical thin film technology, specifically relating to a film structure that cuts off long-wave infrared transmission of lasers and shields radar electromagnetic waves. Background Technology

[0002] Multispectral zinc sulfide infrared windows are key components of airborne infrared search and track systems, used in supersonic airborne environments. Besides fulfilling their functions of transmitting laser signals, blocking long-wave infrared bands, and shielding radar bands, they must also withstand harsh environments such as high-speed airflow, rain erosion, and dust. Therefore, the surface of the zinc sulfide window must be coated with a film structure that, under harsh conditions such as high-speed airflow, rain erosion, and dust, simultaneously fulfills its functions of transmitting laser signals, blocking long-wave infrared bands, and shielding radar bands, while also possessing sufficiently high strength to protect the window. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a membrane structure that provides laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding, wherein the film structure comprises a multispectral zinc sulfide substrate, six thin films disposed on the front side of the multispectral zinc sulfide substrate, and three thin films disposed on the back side of the multispectral zinc sulfide substrate.

[0005] The six thin films disposed on the front side of the multispectral zinc sulfide substrate are, from the inside out, the first NiCr film, the second Au film, the third Ta2O5 film, the fourth SiO2 film, the fifth Ta2O5 film and the sixth SiO2 film.

[0006] The three thin films disposed on the back of the multispectral zinc sulfide substrate, from the inside out, are: the first layer of ITO film, the second layer of Ta2O5 film, and the third layer of SiO2 film.

[0007] The thickness of each film layer is:

[0008] Number of film layers Membrane materials Film thickness / nm 6 floors <![CDATA[SiO2]]> 192.40～193.5 5 floors <![CDATA[Ta2O5]]> 219.01～220 4 floors <![CDATA[SiO2]]> 31.49～32.50 3 floors <![CDATA[Ta2O5]]> 170.43～171.43 2nd floor Au 100～101 1st floor NiCr 30～31.1 Multispectral zinc sulfide substrate 1st floor ITO 280～281 2nd floor <![CDATA[Ta2O5]]> 95.91～97 3 floors <![CDATA[SiO2]]> 181.14～182.25

[0009] The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided by this invention also has the following feature: the thickness of each film layer is:

[0010]

[0011]

[0012] The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided by this invention also has the following feature: the thickness of each film layer is:

[0013] Number of film layers Membrane materials Film thickness / nm 6 floors <![CDATA[SiO2]]> 192.45 5 floors <![CDATA[Ta2O5]]> 219.5 4 floors <![CDATA[SiO2]]> 32 3 floors <![CDATA[Ta2O5]]> 170.8 2nd floor Au 100.2 1st floor NiCr 30.5 Multispectral zinc sulfide substrate 1st floor ITO 280.3 2nd floor <![CDATA[Ta2O5]]> 95.98 3 floors <![CDATA[SiO2]]> 181.35

[0014] The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided by this invention also has the following feature: the thickness of each film layer is:

[0015] Number of film layers Membrane materials Film thickness / nm 6 floors <![CDATA[SiO2]]> 192.45 5 floors <![CDATA[Ta2O5]]> 219.71 4 floors <![CDATA[SiO2]]> 31.87 3 floors <![CDATA[Ta2O5]]> 171.20 2nd floor Au 100.5 1st floor NiCr 30.1 Multispectral zinc sulfide substrate 1st floor ITO 280.80 2nd floor <![CDATA[Ta2O5]]> 97 3 floors <![CDATA[SiO2]]> 182

[0016] The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided by this invention also has the following feature: the thickness of each film layer is:

[0017]

[0018]

[0019] Beneficial effects

[0020] The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided by the present invention has a transmittance of more than 86% for a 1.064μm laser wavelength tested at 0°, an average design value of less than 10% for the transmittance in the 7.7μm to 11μm long-wave infrared band, and a highly efficient radar wave shielding function. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided in an embodiment of the present invention.

[0023] Figure 2 This is a graph showing the transmittance of a 1.064 μm laser wavelength tested at 0° in Example 1 of the present invention.

[0024] Figure 3 This is a transmittance curve of Example 1 of the present invention in the 7.7μm to 11μm long-wave infrared band;

[0025] Figure 4 This is a graph showing the transmittance of a 1.064 μm laser wavelength tested at 0° in Example 2 of the present invention.

[0026] Figure 5 This is a transmittance curve of the long-wave infrared band of 7.7μm to 11μm in Embodiment 2 of the present invention;

[0027] Figure 6 This is a graph showing the transmittance of a 1.064 μm laser wavelength tested at 0° in Example 3 of the present invention.

[0028] Figure 7 This is a transmittance curve of the long-wave infrared band of 7.7μm to 11μm in Example 3 of the present invention;

[0029] Figure 8 This is a transmittance curve of a 1.064 μm laser wavelength tested at 0° in Example 4 of the present invention;

[0030] Figure 9 This is a transmittance curve of the long-wave infrared band of 7.7μm to 11μm in Example 4 of the present invention. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the protection scope of the present invention.

[0032] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0033] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0034] The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of these terms in this invention based on the specific circumstances.

[0035] like Figure 1As shown, this embodiment provides a film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding. The film structure includes a multispectral zinc sulfide substrate, six thin films disposed on the front side of the multispectral zinc sulfide substrate, and three thin films disposed on the back side of the multispectral zinc sulfide substrate.

[0036] The six thin films disposed on the front side of the multispectral zinc sulfide substrate are, from the inside out, the first NiCr film, the second Au film, the third Ta2O5 film, the fourth SiO2 film, the fifth Ta2O5 film and the sixth SiO2 film.

[0037] The three thin films disposed on the back of the multispectral zinc sulfide substrate, from the inside out, are: the first layer of ITO film, the second layer of Ta2O5 film, and the third layer of SiO2 film.

[0038] The thickness of each film layer is:

[0039] Number of film layers Membrane materials Film thickness / nm 6 floors <![CDATA[SiO2]]> 192.40～193.5 5 floors <![CDATA[Ta2O5]]> 219.01～220 4 floors <![CDATA[SiO2]]> 31.49～32.50 3 floors <![CDATA[Ta2O5]]> 170.43～171.43 2nd floor Au 100～101 1st floor NiCr 30～31.1 Multispectral zinc sulfide substrate 1st floor ITO 280～281 2nd floor <![CDATA[Ta2O5]]> 95.91～97 3 floors <![CDATA[SiO2]]> 181.14～182.25

[0040] Example 1:

[0041] A film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding is provided, comprising a multispectral zinc sulfide substrate, six layers of thin films on the front side, and three layers of thin films on the back side. The first layer on the front side is a NiCr film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is an Au film deposited on the NiCr film; the third layer is a Ta2O5 film deposited on the Au film; the fourth layer is a SiO2 film deposited on the Ta2O5 film; the fifth layer is a Ta2O5 film deposited on the SiO2 film; and the sixth layer is a SiO2 film deposited on the Ta2O5 film. The three layers of thin films on the back side consist of three layers from the inside out: the first layer is an ITO film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is a Ta2O5 film deposited on the ITO film; and the third layer is a SiO2 film deposited on the Ta2O5 film. The thickness of each film layer is as follows:

[0042] Number of film layers Membrane materials Film thickness / nm 6 floors <![CDATA[SiO2]]> 192.5 5 floors <![CDATA[Ta2O5]]> 219.25 4 floors <![CDATA[SiO2]]> 31.65 3 floors <![CDATA[Ta2O5]]> 170.6 2nd floor Au 100 1st floor NiCr 30.25 Multispectral zinc sulfide substrate 1st floor ITO 280 2nd floor <![CDATA[Ta2O5]]> 95.95 3 floors <![CDATA[SiO2]]> 181.2

[0043] After testing, such as Figure 2 As shown, the transmittance of a 1.064μm laser wavelength tested at 0° is greater than 86%; Figure 3 As shown, the average design value of transmittance in the 7.7μm to 11μm long-wave infrared band is less than 10%.

[0044] Example 2:

[0045] A film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding is provided, comprising a multispectral zinc sulfide substrate, six layers of thin films on the front side, and three layers of thin films on the back side. The first layer on the front side is a NiCr film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is an Au film deposited on the NiCr film; the third layer is a Ta2O5 film deposited on the Au film; the fourth layer is a SiO2 film deposited on the Ta2O5 film; the fifth layer is a Ta2O5 film deposited on the SiO2 film; and the sixth layer is a SiO2 film deposited on the Ta2O5 film. The three layers of thin films on the back side consist of three layers from the inside out: the first layer is an ITO film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is a Ta2O5 film deposited on the ITO film; and the third layer is a SiO2 film deposited on the Ta2O5 film. The thickness of each film layer is as follows:

[0046] Number of film layers Membrane materials Film thickness / nm 6 floors <![CDATA[SiO2]]> 192.45 5 floors <![CDATA[Ta2O5]]> 219.5 4 floors <![CDATA[SiO2]]> 32 3 floors <![CDATA[Ta2O5]]> 170.8 2nd floor Au 100.2 1st floor NiCr 30.5 Multispectral zinc sulfide substrate 1st floor ITO 280.3 2nd floor <![CDATA[Ta2O5]]> 95.98 3 floors <![CDATA[SiO2]]> 181.35

[0047] After testing, such as Figure 4 As shown, the transmittance of a 1.064μm laser wavelength tested at 0° is greater than 86%; Figure 5 As shown, the average design value of transmittance in the 7.7μm to 11μm long-wave infrared band is less than 10%.

[0048] Example 3:

[0049] A film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding is provided, comprising a multispectral zinc sulfide substrate, six layers of thin films on the front side, and three layers of thin films on the back side. The first layer on the front side is a NiCr film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is an Au film deposited on the NiCr film; the third layer is a Ta2O5 film deposited on the Au film; the fourth layer is a SiO2 film deposited on the Ta2O5 film; the fifth layer is a Ta2O5 film deposited on the SiO2 film; and the sixth layer is a SiO2 film deposited on the Ta2O5 film. The three layers of thin films on the back side consist of three layers from the inside out: the first layer is an ITO film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is a Ta2O5 film deposited on the ITO film; and the third layer is a SiO2 film deposited on the Ta2O5 film. The thickness of each film layer is as follows:

[0050]

[0051]

[0052] After testing, such as Figure 6 As shown, the transmittance of a 1.064μm laser wavelength tested at 0° is greater than 86%; Figure 7As shown, the average design value of transmittance in the 7.7μm to 11μm long-wave infrared band is less than 10%.

[0053] Example 4:

[0054] A film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding is provided, comprising a multispectral zinc sulfide substrate, six layers of thin films on the front side, and three layers of thin films on the back side. The first layer on the front side is a NiCr film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is an Au film deposited on the NiCr film; the third layer is a Ta2O5 film deposited on the Au film; the fourth layer is a SiO2 film deposited on the Ta2O5 film; the fifth layer is a Ta2O5 film deposited on the SiO2 film; and the sixth layer is a SiO2 film deposited on the Ta2O5 film. The three layers of thin films on the back side consist of three layers from the inside out: the first layer is an ITO film deposited on the surface of the multispectral zinc sulfide substrate; the second layer is a Ta2O5 film deposited on the ITO film; and the third layer is a SiO2 film deposited on the Ta2O5 film. The thickness of each film layer is as follows:

[0055]

[0056]

[0057] After testing, such as Figure 8 As shown, the transmittance of a 1.064μm laser wavelength tested at 0° is greater than 86%; Figure 9 As shown, the average design value of transmittance in the 7.7μm to 11μm long-wave infrared band is less than 10%.

[0058] In summary, the film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding provided in the above embodiments is based on the product's operating waveband and optical performance. To achieve radar electromagnetic wave shielding, a metal mesh is deposited on the surface of a zinc sulfide substrate. NiCr alloy is selected as the bonding layer between the zinc sulfide substrate and the Au film in the metal mesh design because NiCr alloy can effectively improve the adhesion between the zinc sulfide substrate and the Au film, enhancing the environmental reliability of the film layer. Furthermore, the Au film is selected based on its excellent chemical properties, superior mechanical and adhesion properties, and its performance increases with usage time. The NiCr alloy thickness is designed to be 30–31.1 nm, and the Au film thickness to be 100–101 nm. This thickness was determined through experimental iteration to be the optimal thickness, as this combination of thicknesses meets the technical requirement of a metal mesh resistance value ≤15Ω, thus achieving the functional requirement of radar electromagnetic wave shielding.

[0059] Furthermore, the SiO2 and Ta2O5 films are deposited on the metal mesh, and the ITO, SiO2 and Ta2O5 films are deposited on the other side of the zinc sulfide substrate to improve the transmittance of the zinc sulfide substrate at a laser wavelength of 1.064 μm, and to achieve an average transmittance of less than 10% in the long-wave infrared band of 7.7 μm to 11 μm. These three materials were selected based on meeting the material property requirements in the table below.

[0060] Dielectric thin film material property requirements table:

[0061] characteristic Require Refractive index Prescribed, uniform, repeatable transmission <![CDATA[High, absorption value k < 10 -4 > scattering Small Geometric thickness Prescribed, repeatable Adhesion high hardness high Laser radiation resistance as high as possible Structural defects as few as possible

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. 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 technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding, characterized in that, The membrane structure includes a multispectral zinc sulfide substrate, six thin films disposed on the front side of the multispectral zinc sulfide substrate, and three thin films disposed on the back side of the multispectral zinc sulfide substrate. The six thin films disposed on the front side of the multispectral zinc sulfide substrate, from the inside out, are: a NiCr film, an Au film, a Ta2O5 film, a SiO2 film, a Ta2O5 film, and a SiO2 film; the three thin films disposed on the back side of the multispectral zinc sulfide substrate, from the inside out, are: an ITO film, a Ta2O5 film, and a SiO2 film. In this process, Au and NiCr films are combined and deposited to form a metal mesh structure, where the NiCr film serves as the connector between the metal mesh structure and the multispectral zinc sulfide substrate. The thickness of each film layer is as follows: 。 2. The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding according to claim 1, characterized in that, The thickness of each film layer is as follows: 。 3. The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding according to claim 1, characterized in that, The thickness of each film layer is as follows: 。 4. The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding according to claim 1, characterized in that, The thickness of each film layer is as follows: 。 5. The film structure for laser transmission long-wave infrared cutoff and radar electromagnetic wave shielding according to claim 1, characterized in that, The thickness of each film layer is as follows: 。

Images