Optical attenuation film and preparation method thereof

Abstract

The invention discloses an optical attenuation film and a preparation method thereof, the optical attenuation film comprises a substrate, an attenuation layer and a protection layer, and the substrate has a first surface and a second surface which are opposite to each other; the attenuation layer is arranged on the first surface or the second surface of the substrate; the protection layer is arranged on the side, away from the substrate, of the attenuation layer, the protection layer is a polysilazane coating, and the projection area of the protection layer is larger than or equal to the projection area of the attenuation layer in the preset projection direction perpendicular to the first surface. By additionally arranging the protective layer on the attenuation layer and enabling the protective layer to be the hydrophobic polysilazane coating, pollutants such as acidic and alkaline substances, water vapor and dust can be prevented from being adsorbed on the optical attenuation film, the probability that the attenuation layer is corroded by external substances is reduced, and the service life of the optical attenuation film is prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of optical filters, and in particular to an optical attenuation film and a preparation method thereof. Background Art

[0002] Neutral density filters, also known as optical attenuation films, medium gray density filters, neutral density filters, and neutral gray filters, are used to attenuate the energy of incident light, and this attenuation is non-selective, that is, within the effective range of action, all different wavelengths of light are attenuated equally and evenly. Therefore, neutral density filters only play a role in reducing the intensity of light and will not have any effect on the color of the original object, and can truly reproduce the contrast of the scene.

[0003] Neutral density filters are usually made by depositing a light absorbing medium on a transparent substrate, for example, a metal film layer is deposited on a transparent substrate. Since the metal film layer is directly exposed to the air, it is easy to be oxidized or scratched, and the metal film layer is easily corroded when it comes into contact with foreign substances (such as salt spray, acid, alkali), thus affecting the service life of the neutral density filter. Summary of the invention

[0004] The embodiments of the present application provide an optical attenuation film and a method for preparing the same that can at least partially solve at least one of the above-mentioned disadvantages or other disadvantages in the prior art.

[0005] The first aspect of the present application provides an optical attenuation film, which includes a substrate, an attenuation layer and a protective layer; the substrate has a first surface and a second surface relative to each other; the attenuation layer is arranged on the first surface or the second surface of the substrate; the protective layer is arranged on the side of the attenuation layer away from the substrate, the protective layer is a polysilazane coating, and in a preset projection direction perpendicular to the first surface, the projection area of ​​the protective layer is greater than or equal to the projection area of ​​the attenuation layer.

[0006] According to some exemplary embodiments of the present application, the polysilazane coating is an organic polysilazane coating or a perhydropolysilazane coating.

[0007] According to some exemplary embodiments of the present application, the polysilazane coating is a ceramic coating.

[0008] According to some exemplary embodiments of the present application, the hydrophobic angle of the polysilazane coating is greater than or equal to 100°.

[0009] According to some exemplary embodiments of the present application, the optical attenuation film further includes a transition layer, which is disposed between the attenuation layer and the protective layer, or between the substrate and the attenuation layer, and the transition layer includes one or more of an aluminum oxide layer, a silicon oxide layer, a silicon aluminum oxide layer, a silicon layer, a germanium layer, a zinc sulfide layer, and a magnesium fluoride layer.

[0010] According to some exemplary embodiments of the present application, the attenuation layer includes one or more of a chromium layer, a nickel-chromium alloy layer, and a copper layer.

[0011] According to some exemplary embodiments of the present application, the substrate includes one or more of a silicon layer, a germanium layer, a zinc sulfide layer, and a zinc selenide layer.

[0012] According to some exemplary embodiments of the present application, within the optical wavelength range of 8 μm to 14 μm, the transmittance of the optical attenuation film to light is 0.1% to 40%.

[0013] According to some exemplary embodiments of the present application, the thickness of the polysilazane coating is 10 nm to 30 nm.

[0014] According to some exemplary embodiments of the present application, the thickness of the attenuation layer is 5 nm to 150 nm.

[0015] According to some exemplary embodiments of the present application, the thickness of the transition layer is 10 nm to 30 nm.

[0016] According to some exemplary embodiments of the present application, an anti-reflection layer is disposed on a side of the substrate away from the attenuation layer.

[0017] A second aspect of the present application provides a method for preparing an optical attenuation film, comprising: forming an attenuation layer on a substrate; and forming a protective layer on a side of the attenuation layer away from the substrate, wherein the protective layer is a polysilazane coating.

[0018] According to some exemplary embodiments of the present application, forming an attenuation layer on a substrate includes: keeping the substrate at a constant temperature of 100° C. for 30 min to 60 min; and plating chromium or nickel-chromium alloy on the substrate in an environment of inert gas and a vacuum degree less than 1.0E-3Pa to form an attenuation layer.

[0019] According to some exemplary embodiments of the present application, before plating chromium or nickel-chromium alloy on the substrate to form the attenuation layer, the method further includes: plating silicon oxide on the substrate to form a transition layer.

[0020] According to some exemplary embodiments of the present application, the inert gas is argon, and the gas flow rate of argon is 8 SCCM to 10 SCCM; the evaporation rate of chromium or nickel-chromium alloy is 0.05 nm / s to 0.1 nm / s; and the evaporation rate of silicon oxide is 0.15 nm / s to 0.2 nm / s.

[0021] According to some exemplary embodiments of the present application, forming a protective layer on the side of the attenuation layer away from the substrate includes: keeping the substrate at a constant temperature of 200° C. for 30 min to 60 min; and coating a polysilazane coating on the side of the attenuation layer away from the substrate to form the protective layer.

[0022] The optical attenuation film provided by the present application can prevent pollutants such as acidic and alkaline substances, water vapor, and dust from being adsorbed on the optical attenuation film by adding a protective layer on the attenuation layer and making the protective layer a hydrophobic polysilazane coating, thereby reducing the probability of the attenuation layer being corroded by external substances and extending the service life of the optical attenuation film. At the same time, the protective layer is used to completely shield the attenuation layer, further improving the protective ability of the protective layer to the attenuation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Other features, purposes and advantages of the embodiments of the present application will become more apparent by reading the detailed description of the non-limiting embodiments made with reference to the following drawings, in which:

[0024] Figure 1 is a schematic structural diagram of an optical attenuation film according to an exemplary embodiment of the present application;

[0025] Figure 2 is a schematic structural diagram of an optical attenuation film according to an exemplary embodiment of the present application;

[0026] Figure 3 is a schematic structural diagram of an optical attenuation film according to an exemplary embodiment of the present application;

[0027] Figure 4 It is a schematic diagram of the transmittance of light to an optical attenuation film without an attenuation layer and an optical attenuation film with an attenuation layer thickness of 20 nm;

[0028] Figure 5 It is a schematic diagram of the transmittance of light to an optical attenuation film without an attenuation layer and an optical attenuation film with an attenuation layer thickness of 100 nm;

[0029] Figure 6 It is a schematic flow chart of a method for preparing an optical attenuation film according to an exemplary embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to better understand the present application, a more detailed description will be made of various aspects of the present application with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and are not intended to limit the scope of the present application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0031] It should be noted that in this specification, the terms "upper", "lower", etc. indicate positions or state relationships based on the positions or state relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0032] In this specification, the terms "first", "second", etc. are used only to distinguish one feature from another feature, and do not represent any limitation on the features. Therefore, without departing from the teachings of this application, the first surface discussed below may be referred to as the second surface, and the second surface may also be referred to as the first surface.

[0033] In the drawings, the thickness, size and shape of each component may be slightly exaggerated for convenience of explanation. The drawings are only examples and are not drawn strictly to scale.

[0034] It should also be understood that the terms “comprising,” “including,” and / or “having,” when used in this specification, indicate the presence of stated features, elements, and / or components, but do not exclude the presence of one or more other features, elements, components, and / or combinations thereof.

[0035] Unless otherwise defined, all terms (including technical terms and scientific terms) used in this application have the same meaning as commonly understood by ordinary technicians in the field to which this application belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be understood to have the same meaning as their meaning in the context of the relevant technology, and should not be interpreted in an idealized or overly formal sense, unless explicitly defined in this application.

[0036] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] The neutral density filter may include a light-transmitting substrate and a metal film layer, wherein the metal film layer is disposed on the surface of the light-transmitting substrate for light to pass through and attenuates the light. Since the metal film layer is directly exposed to the air, the metal film layer is easily oxidized or scratched. More seriously, when the neutral density filter is exposed to salt spray, acid, alkali and other environments, the metal film layer is easily corroded, thereby reducing the service life of the neutral density filter.

[0038] In order to solve the above problems, a silicon dioxide layer is usually deposited on the side of the metal film layer away from the light-transmitting substrate. The silicon dioxide layer prevents the metal film layer from being directly exposed to the air, thereby preventing the metal film layer from being oxidized or scratched. However, when the neutral density filter is exposed to salt spray, acid, alkali and other environments, the silicon dioxide layer will be corroded due to its reaction with salt spray, acid, alkali and other substances, resulting in the failure of the silicon dioxide layer to protect the metal film layer. The metal film layer is still at risk of being oxidized or scratched.

[0039] In order to at least partially solve one or more of the above problems and other potential problems, the present application proposes an optical attenuation film, and more specifically, proposes an optical attenuation film that uses a polysilazane coating as a protective layer to protect an attenuation layer.

[0040] Figure 1 1 is a schematic diagram of the structure of an optical attenuation film 100 according to an exemplary embodiment of the present application. The optical attenuation film 100 can attenuate infrared light, for example. It should be understood that the optical attenuation film 100 can also attenuate light in other wavelengths, and the present application does not impose any specific limitation on this.

[0041] refer to Figure 1 , the optical attenuation film 100 may include a substrate 110, an attenuation layer 120 and a protective layer 130. The substrate 110 has high light transmittance to light and has a first surface and a second surface opposite to each other for transmitting light. The attenuation layer 120 may be disposed on the first surface or the second surface of the substrate 110 and attenuate the light. The protective layer 130 may be disposed on the side of the attenuation layer 120 away from the substrate 110 and is a polysilazane coating, which is a coating formed by curing a substance containing polysilazane. In a preset projection direction perpendicular to the first surface, the projection area of ​​the protective layer 130 is greater than or equal to the projection area of ​​the attenuation layer 120. In other words, the projection area of ​​the attenuation layer 120 coincides with the projection area of ​​the protective layer 130, or the projection area of ​​the attenuation layer 120 falls within the projection area of ​​the protective layer 130. The above-mentioned light may be infrared light.

[0042] By adding a protective layer 130 on the attenuation layer 120 and making the protective layer 130 a hydrophobic polysilazane coating, it is possible to prevent pollutants such as acidic and alkaline substances, water vapor, and dust from being adsorbed on the optical attenuation film 100, and the polysilazane coating is difficult to react with salt spray, acid, alkali, and other substances, thereby reducing the probability of the attenuation layer 120 being corroded by external substances such as salt spray, acid, and alkali, improving the protective ability of the protective layer 130 on the attenuation layer 120, and extending the service life of the optical attenuation film 100. At the same time, the protective layer 130 is used to completely shield the attenuation layer 120, further improving the protective ability of the protective layer 130 on the attenuation layer 120.

[0043] In an exemplary embodiment, the substrate 110 may include one or more of a silicon layer, a germanium layer, a zinc sulfide layer, and a zinc selenide layer. The attenuation layer 120 may include one or more of a chromium layer, a nickel-chromium alloy layer, and a copper layer. The attenuation layer 120 is preferably a chromium layer. The substrate 110 has high light transmittance for infrared light. After the infrared light passes through the substrate 110, it reaches the attenuation layer 120. The attenuation layer 120 attenuates the infrared light that passes through, so as to achieve the purpose of weakening the light intensity of the infrared light and not causing any change to the color of the original object, thereby truly reproducing the original color of the object. An anti-reflection layer 150 may be provided on one side of the substrate 110 away from the attenuation layer 120. The wavelength of the infrared light may be 8 μm to 14 μm. The thickness of the substrate 110 is 1 mm to 3 mm, preferably 2 mm. The thickness of the attenuation layer 120 is 5 nm to 150 nm, preferably 100 nm.

[0044] In an exemplary embodiment, the polysilazane coating may be a ceramic coating formed by curing a coating containing an organic polysilazane and / or a perhydropolysilazane. Alternatively, the polysilazane coating may be an organic polysilazane coating or a perhydropolysilazane coating, wherein the organic polysilazane coating is a film formed by curing a coating mixed with an organic polysilazane and a resin, and the perhydropolysilazane coating is a film formed by curing a coating mixed with a perhydropolysilazane and a resin. The molecular weight of the organic polysilazane or perhydropolysilazane is 300 to 2000, preferably 500 to 1000. The above-mentioned polysilazane coating has the characteristics of high adhesion, high hydrophobicity, excellent acid and alkali resistance, high hardness, etc. When it is applied to the protective layer of the attenuation layer 120, it can provide excellent protection for the attenuation layer 120. The thickness of the polysilazane coating is 10nm to 30nm. The hydrophobic angle of the polysilazane coating may be greater than or equal to 100°, preferably 110° to 120°.

[0045] In an exemplary embodiment, the optical attenuation film 100 may further include a transition layer 140, which is disposed between the attenuation layer 120 and the protective layer 130, or between the substrate 110 and the attenuation layer 120. The transition layer 140 may include one or more of an aluminum oxide layer, a silicon oxide layer, a silicon aluminum oxide layer, a silicon layer, a germanium layer, a zinc sulfide layer, and a magnesium fluoride layer. The thickness of the transition layer 140 is 5 nm to 30 nm. By disposing the transition layer 140 between the attenuation layer 120 and the protective layer 130 or between the substrate 110 and the attenuation layer 120, the adhesion between the attenuation layer 120 and the protective layer 130 or the substrate 110 can be improved, thereby improving the stability of the optical attenuation film 100.

[0046] As an example, refer to Figure 1The transition layer 140 is only disposed between the attenuation layer 120 and the protection layer 130. The transition layer 140 includes one or more of an aluminum oxide layer, a silicon oxide layer, and a magnesium fluoride layer. The thickness of the transition layer 140 is 5 nm to 20 nm.

[0047] As an example, refer to Figure 2 The transition layer 140 may include a first transition layer 141 and a second transition layer 142. The first transition layer 141 is disposed between the substrate 110 and the attenuation layer 120, and the second transition layer 142 is disposed between the attenuation layer 120 and the protective layer 130. The first transition layer 141 may include one or more of an aluminum oxide layer, a silicon oxide layer, a silicon layer, and a germanium layer. The second transition layer 142 may include one or more of an aluminum oxide layer, a silicon oxide layer, and a magnesium fluoride layer. The thickness of the first transition layer 141 is 5 nm to 10 nm. The thickness of the second transition layer 142 is 5 nm to 20 nm.

[0048] As an example, the transition layer 140 includes a dielectric layer, which may be an aluminum oxide layer.

[0049] As an example, the transition layer 140 includes a first dielectric layer and a second dielectric layer alternately stacked, the first dielectric layer may be an aluminum oxide layer, and the second dielectric layer may be a magnesium fluoride layer. The number of alternations of the first dielectric layer and the second dielectric layer may be 1 to 4. The first dielectric layer and the second dielectric layer may be a stacked pair, and in each stacked pair, the first dielectric layer is closer to the substrate 110 than the second dielectric layer.

[0050] It should be understood that the specific structure of the transition layer 140 is merely exemplary, and the transition layer 140 may also have other structures that can satisfy the above-mentioned effects, and the present application does not impose any specific limitation on this.

[0051] After the optical attenuation film 100 provided by the present application is provided with a polysilazane coating as a protective layer 130 on its surface, it can prevent pollutants such as acidic and alkaline substances, water vapor, and dust from being adsorbed on the optical attenuation film 100, and at the same time reduce the probability of the attenuation layer 120 being corroded by external substances such as salt spray, acid, and alkali, thereby extending the service life of the optical attenuation film 100. In addition, according to the reliability test "MIL-C-48497A", ​​it can be seen that the protective layer 130 does not fall off; according to the moderate friction test, it can be seen that the protective layer 130 has no scratches; according to the high temperature and high humidity aging test, it can be seen that the protective layer 130 does not fall off after being placed in a high temperature and high humidity environment for 1000 hours; according to the salt spray test of "MIL-STD-810H", it can be seen that the protective layer 130 does not fall off after being placed in a salt spray environment for 1000 hours. The transmittance of the optical attenuation film 100 to infrared light is 0.1% to 40%. The hydrophobic angle of the optical attenuation film 100 can be 110° to 120°, preferably 116°. Therefore, the optical attenuation film 100 provided in the present application has good stability, and compared with the optical attenuation film without the protective layer 130 , the hydrophobic angle of the optical attenuation film 100 can be increased from 65° to 116°.

[0052] Figure 6 The optical attenuation film manufacturing method 1000 according to the present application is shown. The attenuation film 100 mentioned above can be formed by using the manufacturing method 1000 .

[0053] refer to Figure 6 The method 1000 for preparing an optical attenuation film may include the following steps:

[0054] S100, forming a damping layer on a substrate.

[0055] As an example, the substrate is kept at a constant temperature of 100°C for 30 minutes to 60 minutes; in an environment of inert gas and a vacuum degree less than 1.0E-3Pa, chromium or nickel-chromium alloy is plated on the substrate to form an attenuation layer. The thickness of the attenuation layer is 5nm to 150nm, preferably 100nm. The inert gas is argon, and the gas flow rate of argon is 8SCCM to 10SCCM. The evaporation rate of chromium or nickel-chromium alloy is 0.05nm / s to 0.1nm / s. The substrate includes but is not limited to silicon, germanium, zinc sulfide or zinc selenide substrates with high transmittance to infrared light.

[0056] As an example, before forming the attenuation layer, silicon oxide is plated on the substrate in an environment of inert gas and vacuum less than 1.0E-3 Pa to form a transition layer. The thickness of the transition layer is 5nm to 20nm. The inert gas is argon gas, and the gas flow rate of argon gas is 8SCCM to 10SCCM. The evaporation rate of silicon oxide is 0.15nm / s to 0.2nm / s.

[0057] S200, forming a protective layer on a side of the attenuation layer away from the substrate, wherein the protective layer is a polysilazane coating.

[0058] As an example, the substrate is kept at a constant temperature of 200°C for 30 to 60 minutes; a polysilazane coating is plated on the side of the attenuation layer away from the substrate to form a protective layer. The thickness of the protective layer is 10 nm to 30 nm. The polysilazane coating is a coating containing organic polysilazane and / or perhydropolysilazane. The molecular weight of the organic polysilazane or perhydropolysilazane is 300 to 2000, preferably 500 to 1000.

[0059] The following describes the method 1000 for preparing an optical attenuation film using a specific embodiment.

[0060] First, a substrate with high transmittance to infrared light such as silicon, germanium, zinc sulfide or zinc selenide is selected as a substrate, and an anti-reflection layer is plated on one side of the substrate. Then, the substrate is heated to 100°C and kept at a constant temperature for 30 to 60 minutes. In an environment of inert gas and a vacuum degree less than 1.0E-3Pa, an attenuation layer and a transition layer are sequentially plated on the side of the substrate where the anti-reflection layer is not provided. Specifically, chromium or nickel-chromium alloy is used as the coating material of the attenuation layer, silicon oxide is used as the coating material of the transition layer, and electron gun plating is used. The evaporation rate of chromium or nickel-chromium alloy is 0.05nm / s to 0.1nm / s, and the evaporation rate of silicon oxide is 0.15nm / s to 0.2nm / s. Ion beam assistance is used, the discharge voltage is 150V to 200V, the discharge current is 1.2A to 1.5A, the inert gas is argon, and the gas flow rate is 8SCCM to 10SCCM. Finally, the temperature is raised to 200°C and kept constant for 30 to 60 minutes, and a protective layer is plated on the side of the transition layer away from the attenuation layer. Specifically, polysilazane coating is used as the coating material of the protective layer, and a resistance heating method is adopted with an evaporation rate of 0.5 nm / s to 1 nm / s, without the need for ion beam assistance.

[0061] Specific embodiments of the optical attenuation film 100 applicable to the above-mentioned embodiments are further described below.

[0062] Example 1

[0063] Figure 1 A schematic structural diagram of the optical attenuation film 100 of Example 1 is shown.

[0064] refer to Figure 1 The optical attenuation film 100 may include a substrate 110 having a first surface and a second surface opposite to each other for transmitting light. The substrate 110 may include one or more of a silicon layer, a germanium layer, a zinc sulfide layer, and a zinc selenide layer. The thickness of the substrate 110 may be 2 mm. The light may be an infrared light with a wavelength range of 8 μm to 12 μm.

[0065] The attenuation layer 120, the transition layer 140 and the protective layer 130 are sequentially arranged on the first surface or the second surface of the substrate 110. The attenuation layer 120 may include one or more of a chromium layer, a nickel-chromium alloy layer, and a copper layer, and the thickness of the attenuation layer 120 is 5nm to 150nm. The attenuation layer 120 is preferably a chromium layer. The transition layer 140 may include one or more of an aluminum oxide layer, a silicon oxide layer, a silicon aluminum oxide layer, a silicon layer, a germanium layer, a zinc sulfide layer, and a magnesium fluoride layer, and the thickness of the transition layer 140 may be 5nm. The protective layer 130 may include a polysilazane coating, and the thickness of the protective layer 130 may be 20nm.

[0066] Example 2

[0067] Figure 2 The schematic diagram of the structure of the optical attenuation film 100 of Example 2 is shown. The difference between Example 2 and Example 1 is that the transition layer 140 includes a first transition layer 141 and a second transition layer 142, the first transition layer 141 is arranged between the substrate 110 and the attenuation layer 120, and the second transition layer 142 is arranged between the attenuation layer 120 and the protective layer 130. The same parts are not repeated in this application, and only the differences are described.

[0068] refer to Figure 2 The transition layer 140 may include a first transition layer 141 and a second transition layer 142. The first transition layer 141 is disposed between the substrate 110 and the attenuation layer 120, and the second transition layer 142 is disposed between the attenuation layer 120 and the protective layer 130. The first transition layer 141 may include one or more of an aluminum oxide layer, a silicon oxide layer, a silicon layer, and a germanium layer. The second transition layer 142 may include one or more of an aluminum oxide layer, a silicon oxide layer, and a magnesium fluoride layer. The thickness of the first transition layer 141 is 5 nm. The thickness of the second transition layer 142 is 5 nm.

[0069] Figure 4 The transmittance of the optical attenuation film 100 to light is shown when there is no attenuation layer 120 and the thickness of the attenuation layer 120 is 20 nm. Figure 5 FIG. 1 shows the transmittance of the optical attenuation film 100 to light when there is no attenuation layer 120 and the thickness of the attenuation layer 120 is 1000 nm. Figure 4 and Figure 5From the above, compared with the optical attenuation film 100 without the attenuation layer 120, the optical attenuation film 100 with the attenuation layer 120 can significantly reduce the transmittance of light, and as the thickness of the attenuation layer 120 increases, the transmittance of the optical attenuation film 100 to light decreases, and the optical attenuation film 100 has a better attenuation effect on light. When the thickness of the attenuation layer 120 is 20 nm, the transmittance of the optical attenuation film 100 to light is 15% to 25%. When the thickness of the attenuation layer 120 is 100 nm, the transmittance of the optical attenuation film 100 to light is 0.5% to 1.5%.

[0070] Example 3

[0071] Figure 3 The schematic diagram of the structure of the optical attenuation film 100 of Example 3 is shown. The difference between Example 3 and Example 1 or Example 2 is that an anti-reflection layer 150 is disposed on the side of the substrate 110 away from the attenuation layer 120. The same parts will not be described in detail in this application, and only the differences will be described.

[0072] refer to Figure 3 An anti-reflection layer 150 is disposed on a side of the substrate 110 away from the attenuation layer 120 .

[0073] The above is only an exemplary embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present application. These improvements and substitutions should also be regarded as the scope of protection of the present application.

Claims

1. An optical attenuation film, characterized in that: include: a substrate having opposing first and second surfaces; an attenuation layer, disposed on the first surface or the second surface of the substrate; as well as A protective layer is arranged on a side of the attenuation layer away from the substrate, the protective layer is a polysilazane coating, and in a preset projection direction perpendicular to the first surface, a projection area of ​​the protective layer is greater than or equal to a projection area of ​​the attenuation layer.

2. The optical attenuation film according to claim 1, characterized in that: The polysilazane coating is an organic polysilazane coating or a perhydropolysilazane coating.

3. The optical attenuation film according to claim 1, characterized in that: The hydrophobic angle of the polysilazane coating is greater than or equal to 100°.

4. The optical attenuation film according to claim 1, characterized in that: Also includes: A transition layer is arranged between the attenuation layer and the protective layer, or between the substrate and the attenuation layer, and the transition layer includes one or more of an aluminum oxide layer, a silicon oxide layer, a silicon aluminum oxide layer, a silicon layer, a germanium layer, a zinc sulfide layer, and a magnesium fluoride layer.

5. The optical attenuation film according to any one of claims 1 to 4, characterized in that: The attenuation layer includes one or more of a chromium layer, a nickel-chromium alloy layer, and a copper layer.

6. The optical attenuation film according to any one of claims 1 to 4, characterized in that: The substrate includes one or more of a silicon layer, a germanium layer, a zinc sulfide layer, and a zinc selenide layer.

7. The optical attenuation film according to any one of claims 1 to 4, characterized in that: In the optical waveband of 8 μm to 14 μm, the transmittance of the optical attenuation film to light is 0.1% to 40%.

8. The optical attenuation film according to any one of claims 1 to 4, characterized in that: The thickness of the polysilazane coating is 10 nm to 30 nm.

9. The optical attenuation film according to any one of claims 1 to 4, characterized in that: The thickness of the attenuation layer is 5nm-150nm.

10. A method for preparing an optical attenuation film, characterized in that: include: forming a attenuation layer on the substrate; as well as A protective layer is formed on a side of the attenuation layer away from the substrate, wherein the protective layer is a polysilazane coating.

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