A wavelength 190-230 nm metal-dielectric enhanced reflection film and a preparation method thereof

Abstract

The application relates to the technical field of optical films, in particular to a wavelength 190-230 nm metal dielectric enhanced reflection film and a preparation method thereof. The metal dielectric enhanced reflection film comprises a substrate, a main reflection layer and a plurality of dielectric enhancement layers. The main reflection layer is an Al layer. The dielectric enhancement layers are alternately stacked by MgF2 layers and Al2O3 layers. The number of dielectric enhancement layers is not more than 3. The physical thickness of the Al layer is 180+ / -2% nm. The physical thickness of the MgF2 layer is 26.43+ / -2% nm. The physical thickness of the Al2O3 layer is 36.65+ / -2% nm. In the MgF2 layer, the evaporation rate of MgF2 is 0.8+ / -0.1 nm / s. In the Al2O3 layer, the evaporation rate of Al2O3 is 0.5+ / -0.05 nm / s. The metal dielectric enhanced reflection film has stable high reflectivity in the 190-230 nm wavelength band, high compactness and firmness between the film layers, and good durability.

Description

Technical Field

[0001] This application relates to the field of optical thin film technology, and in particular to a metallic dielectric enhanced reflective film with a wavelength of 190-230nm and its preparation method. Background Technology

[0002] In optical systems, a metal-dielectric reflective coating is a composite optical film that combines metal and dielectric materials to improve the reflectivity of light and control the path of light. Such a film is usually made up of one or more layers of highly reflective metals (such as silver, aluminum, gold, etc.) and dielectric materials (such as silicon dioxide, titanium oxide, etc.) stacked alternately. The metal layer provides high reflectivity, while the dielectric layer is used to adjust the optical performance of the film.

[0003] However, current metallic dielectric reinforced reflective films typically exhibit reflectivity below 85% in the 190-230nm wavelength range, resulting in low detection accuracy when applied to gas concentration detection equipment, especially for low-concentration gases. Furthermore, the bonding strength between the film layers in a metallic dielectric reinforced reflective film affects its durability. Therefore, there is a need for a metallic dielectric reinforced reflective film with both high reflectivity and strong interlayer bonding. Summary of the Invention

[0004] The purpose of this application is to overcome the above-mentioned technical problems and provide a metallic dielectric enhanced reflective film with a wavelength of 190-230nm and its preparation method.

[0005] Firstly, the 190-230nm wavelength metallic dielectric enhanced reflective film provided in this application adopts the following technical solution:

[0006] A metallic dielectric enhanced reflective film with a wavelength of 190-230 nm is disclosed. The metallic dielectric enhanced reflective film includes a substrate, a main reflective layer, and several dielectric enhancement layers arranged sequentially. The main reflective layer is an Al layer. The dielectric enhancement layers are composed of alternating layers of MgF2 and Al2O3. The number of dielectric enhancement layers is no more than three. The physical thickness of the Al layer is 180±2% nm, the physical thickness of the MgF2 layer is 26.43±2% nm, and the physical thickness of the Al2O3 layer is 36.65±2% nm. The evaporation rate of Al in the Al layer is 3.0±0.1 nm / s, the evaporation rate of MgF2 in the MgF2 layer is 0.8±0.1 nm / s, and the evaporation rate of Al2O3 in the Al2O3 layer is 0.5±0.05 nm / s.

[0007] By adopting the above technical solution, the Al layer is used as the main reflective layer. Since Al has a low absorption rate in the ultraviolet band, it can achieve high-efficiency reflection. At the same time, MgF2 layer and Al2O3 layer are alternately stacked as the dielectric reinforcement layer. Both MgF2 and Al2O3 materials exhibit excellent light transmittance in the ultraviolet band. After alternating stacking, the reflection effect can be effectively enhanced, thereby significantly improving the reflectivity of the film layer. Furthermore, the number of dielectric reinforcement layers, the thickness control of the Al, MgF2, and Al2O3 layers, and the evaporation rates of the three materials (Al, MgF2, and Al2O3) significantly affect the reflectivity and interlayer bonding strength of the metal dielectric reinforced reflective film. This application controls the number of dielectric reinforcement layers to 1-3 layers, the physical thickness of the Al layer to be within the range of 180±2% nm, the physical thickness of the MgF2 layer to be within the range of 26.43±2% nm, and the physical thickness of the Al2O3 layer to be within the range of 36.65±2% nm. Simultaneously, by coordinating the evaporation rates of Al, MgF2, and Al2O3, the reflectivity of the metal dielectric reinforced reflective film can reach over 90% in the 190-230 nm wavelength range, effectively improving the detection accuracy of gas concentration and making it suitable for detecting low-concentration gases. Furthermore, this metal dielectric reinforced reflective film exhibits high interlayer bonding strength and good wear resistance and durability.

[0008] In some specific embodiments, the film layer design structure of the metal dielectric enhanced reflective film is Sub / aAbLcHdLeH / O, where Sub represents the substrate, O represents air, A represents the Al layer, L represents the MgF2 layer, H represents the Al2O3 layer, a represents the physical thickness of the Al layer, b and d represent the physical thickness of the MgF2 layer, and c and e represent the physical thickness of the Al2O3 layer.

[0009] By adopting the above technical solution, the film layer design structure of the metal dielectric enhanced reflective film is Sub / aAbLcHdLeH / O, that is, the number of dielectric enhancement layers is 2. Here, Sub represents the substrate, O represents air, A represents the Al layer, L represents the MgF2 layer, and H represents the Al2O3 layer. This structural design allows the metal dielectric enhanced reflective film to achieve a reflectivity of over 94% in the ultraviolet band (190-230nm) while considering cost. Applied to the field of gas detection, it can further improve the detection accuracy of gas concentration and is suitable for the detection of low-concentration gases.

[0010] In some specific embodiments, the substrate is made of optical glass K9 or BK7.

[0011] By adopting the above technical solution, double-sided polished optical glass K9 or BK7 is selected as the substrate. These two materials have excellent mechanical and optical properties, which are beneficial to improving the reflectivity of the metal dielectric enhanced reflective film in the ultraviolet band of 190-230nm. They can also effectively improve the flatness and stability of the film layer, thereby improving the overall optical performance of the metal dielectric enhanced reflective film.

[0012] Secondly, the method for preparing a 190-230nm wavelength metallic dielectric enhanced reflective film provided in this application adopts the following technical solution:

[0013] A method for preparing a metallic dielectric enhanced reflective film with a wavelength of 190-230 nm includes the following steps:

[0014] Al is deposited on the surface of the substrate to form the main reflective layer;

[0015] MgF2 and Al2O3 are sequentially and alternately deposited on the surface of the main radiating layer to form a dielectric enhancement layer, thereby obtaining a metal dielectric enhanced reflective film with a wavelength of 190-230nm.

[0016] By adopting the above technical solution, the preparation method can form a main reflective layer and a dielectric enhancement layer on the substrate surface. The main reflective layer is composed of an Al layer, and the dielectric enhancement layer is composed of alternating layers of MgF2 and Al2O3. The resulting metal dielectric enhanced reflective film has a reflectivity of over 90% in the ultraviolet band of 190-230nm, and has excellent mechanical and optical properties.

[0017] In some specific embodiments, when depositing Al, MgF2, and Al2O3 by vapor deposition, the temperature is controlled at 100±2℃, and the vacuum degree is greater than 9.0*10. -3 Pa.

[0018] By adopting the above technical solution, a high temperature of 100±2℃ and a high vacuum degree greater than 9.0×10⁻⁶ can be achieved. -3 Evaporation of Al, MgF2 and Al2O3 under Pa conditions can significantly improve the density and adhesion of the film, reduce the absorption of the film in specific ultraviolet bands, and effectively solve the stress problem between the film layers, making the film layer more robust, thereby improving the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm ultraviolet band.

[0019] In some specific embodiments, the substrate is baked before Al is deposited.

[0020] In some specific implementations, during the baking process, the temperature is controlled at 100±5℃, and the vacuum degree is controlled at 1.8×10⁻⁶. -4 Pa -2.2×10 -4 Pa.

[0021] By adopting the above technical solution, the substrate is pre-treated by baking, with the temperature controlled at 100±5℃ and the vacuum degree at 1.8×10⁻⁶. -4 Pa -2.2×10 -4 Pa can effectively improve the cleanliness and surface activity of the substrate, enhance the adhesion between the subsequent vapor-deposited film layer and the substrate, and thus improve the stability and reflective performance of the metal dielectric enhanced reflective film.

[0022] In some specific embodiments, the surface of the substrate is polished with a polishing liquid before baking the substrate.

[0023] By adopting the above technical solution, the substrate surface is polished with polishing liquid before baking, which effectively improves the smoothness of the substrate surface and ensures the adhesion between the subsequent coating layer and the substrate, thereby improving the overall stability and optical performance of the film layer.

[0024] In some specific embodiments, the polishing process includes the following steps:

[0025] The substrate surface is polished using a polishing slurry prepared with iron oxide powder and anhydrous ethanol; then the polished substrate is wiped with a mixture of anhydrous ethanol and ether to remove surface residue, resulting in a double-sided polished substrate material.

[0026] By adopting the above technical solution, the residual dirt on the substrate surface is effectively removed, the smoothness and cleanliness of the substrate surface are improved, the adhesion between the film layer and the substrate is enhanced, and the overall stability and optical performance of the film layer are improved.

[0027] In summary, this application includes at least one of the following beneficial technical effects:

[0028] By using Al (aluminum) as the main reflective layer material and combining it with MgF2 and Al2O3 as dielectric reinforcement layers, and controlling the number of dielectric reinforcement layers to be no more than 3 layers, the reflectivity of the film in the 190-230nm ultraviolet band reaches Ravg≥90%, which significantly improves the reflectivity of the metal dielectric reinforced reflective film in the 190-230nm ultraviolet band. When the metal dielectric reinforced reflective film is applied to gas detection equipment, it can effectively improve the detection accuracy of gas concentration and is suitable for the detection of low-concentration gases.

[0029] By using a high-temperature, high-vacuum coating method and a specific evaporation rate, the film is prepared in a high-vacuum environment, which reduces the absorption of ultraviolet waves and effectively solves the stress problem between film layers, improving the density and firmness of the film and enhancing its durability.

[0030] By employing a specific substrate cleaning pretreatment method, the smoothness of the substrate surface is improved, ensuring stronger adhesion between the film layer and the substrate, and further enhancing the overall mechanical properties and service life of the film layer. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the metal dielectric enhanced reflective film in Embodiment 1 of this application.

[0032] Figure 2 This is a schematic diagram of the structure of the metal dielectric enhanced reflective film in Embodiment 2 of this application.

[0033] Figure 3 This is a schematic diagram of the structure of the metal dielectric enhanced reflective film in Embodiment 3 of this application.

[0034] Figure 4 This is a reflectivity curve of the metal dielectric enhanced reflective film in Embodiment 1 of this application.

[0035] Figure 5 This is a reflectivity curve of the metal dielectric enhanced reflective film in Embodiment 2 of this application.

[0036] Figure 6 This is a reflectivity curve of the metal dielectric enhanced reflective film in Embodiment 3 of this application.

[0037] Figure 7 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 1 of this application.

[0038] Figure 8 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 2 of this application.

[0039] Figure 9 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 3 of this application.

[0040] Figure 10 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 4 of this application.

[0041] Figure 11 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 5 of this application.

[0042] Figure 12 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 6 of this application.

[0043] Figure 13 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 7 of this application.

[0044] Figure 14 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 8 of this application.

[0045] Figure 15 This is a reflectance curve of the metallic dielectric enhanced reflective film in Comparative Example 9 of this application. Attached Figure Description

[0047] 1. Substrate; 2. Main reflective layer; 3. Dielectric enhancement layer; 31. MgF2 layer; 32. Al2O3 layer. Detailed Implementation

[0048] The technical solutions in the embodiments of the present invention will now be clearly and completely described in conjunction with the accompanying drawings.

[0049] The inventors of this application have discovered that in the field of optics, in order to obtain a metallic dielectric enhanced reflective film with high reflectivity in the ultraviolet band (190-230nm), it is difficult to maintain a stable high reflectivity in a specific ultraviolet band due to limitations in existing film design, coating processes, and thin film material selection. Therefore, this application mainly adopts the following scheme, achieving a reflectivity of not less than 90% in the ultraviolet band (190-230nm), which is further described in detail below. (Refer to...) Figure 1 and Figure 2 The present application provides a 190-230nm wavelength metallic dielectric enhanced reflective film comprising a substrate 1, a main reflective layer 2 and a dielectric enhancement layer 3. The main reflective layer 2 is an Al layer, and the dielectric enhancement layer 3 is composed of alternating layers of MgF2 layer 31 and Al2O3 layer 32.

[0050] The preferred metal dielectric enhanced reflective film layer design structure is: Sub / aAbLcHdLeH / O. Here, Sub represents a BK7 or K9 optical glass substrate 1, O represents air, A represents the Al layer 31, L represents the MgF2 layer 32, H represents the Al2O3 layer 32, and the specific values ​​of ae are 180±2%nm, 26.43±2%nm, 36.65±2%nm, 26.43±2%nm, and 36.65±2%nm, respectively.

[0051] Since the required reflection band for this application is 190-230nm and the reflectivity requirement is high, an Al (aluminum) layer is selected as the main reflective layer 2 because Al has a low absorption rate in this ultraviolet band.

[0052] The dielectric reinforcement layer 3 uses an alternating stacked structure of MgF2 layer 31 and Al2O3 layer 32. The MgF2 material has a transmittance range of 100-800 nm, reaching over 80% at 170 nm. The Al2O3 material has a transmittance of over 70-85% in the 200-800 nm wavelength range, reaching over 90% at 200 nm. Both MgF2 and Al2O3 materials exhibit excellent performance and high transmittance in the ultraviolet band, thus acting as an anti-reflection agent to further improve the reflectivity of the metallic dielectric reinforced reflective film in the 190-230 nm range.

[0053] This application provides a method for preparing a metallic dielectric enhanced reflective film with a wavelength of 190-230nm, comprising the following steps:

[0054] With an initial vacuum of 1.8 × 10⁻⁶ -4 Pa -2.2×10 -4 The substrate was baked in an environment with a temperature of 100℃±2℃.

[0055] Al is vapor-deposited on the surface of the baked substrate 1 to form the main reflective layer 2;

[0056] MgF2 and Al2O3 are sequentially and alternately deposited on the surface of the main radiating layer 2 to form the dielectric enhancement layer 3, thereby obtaining a metal dielectric enhanced reflective film with a wavelength of 190-230nm.

[0057] When vapor-depositing Al, MgF2, and Al2O3, the deposition process begins after maintaining a constant temperature of 100±2℃ for 30 minutes, while maintaining a vacuum level greater than 9.0*10⁻⁶ without purging with process gas. -3 Pa. Among them, the high vacuum environment can reduce the absorption of ultraviolet band in the 190-230nm range by the metal dielectric enhanced reflective film, while the high temperature environment effectively solves the stress problem between film layers, improves the density of the film layer, makes the film layer more robust, and has a longer lifespan. It improves the environmental durability of the metal dielectric enhanced reflective film, effectively maintains the surface smoothness of the substrate, and obtains a metal dielectric reflective film with excellent optical performance, strong film adhesion, and abrasion resistance.

[0058] Controlling the conditions during film preparation is crucial. The preparation conditions of each film layer not only affect the compactness and other properties of the individual film layer, but also the adhesion with adjacent film layers and the overall optical properties of the film layer. Among these, the selection of the material evaporation rate is particularly important. Through long-term research and development practice, the inventors of this application have found that in this film system, the film layer with the best compactness and adhesion with adjacent film layers is obtained when the evaporation rate of Al is 3.0±0.1 nm / s, the evaporation rate of MgF2 is 0.8±0.1 nm / s, and the evaporation rate of Al2O3 is 0.5±0.05 nm / s.

[0059] In addition, to better ensure adhesion, substrate 1 is cleaned before coating. The cleaning steps are as follows:

[0060] The surface of substrate 1 is polished with a polishing solution prepared by iron oxide powder and anhydrous ethanol using a degreased cotton swab; then the polished substrate 1 is wiped with a mixture of anhydrous ethanol and ether using a degreased cotton swab to remove surface residue, thus obtaining a double-sided polished substrate material; wherein the weight ratio of iron oxide powder to anhydrous ethanol in the polishing solution is 1:(50-70), and the weight ratio of anhydrous ethanol to ether in the mixture of anhydrous ethanol and ether is 1:(2-4).

[0061] By strictly controlling the pretreatment of substrate 1, especially the cleaning process, high adhesion and smoothness of the film layer before coating were ensured. The cleaning step not only effectively removed dust and impurities from the surface of substrate 1, but also provided an ideal surface for the subsequent vapor deposition process. Combined with the material selection and process optimization in the above embodiments, the entire metallic dielectric enhanced reflective film not only achieved the expected effect in reflectivity, but also significantly improved its mechanical properties, meeting the needs of high-end optical equipment.

[0062] The following section provides further explanation of this application in conjunction with specific experiments.

[0063]

Example 1

[0064] A metallic dielectric enhanced reflective film, reference Figure 1 The metallic dielectric enhanced reflective film comprises a substrate 1, a main reflective layer 2, and a dielectric enhancement layer 3. The specific film layer design structure is: Sub / aAbLcH / O, where Sub represents the K9 optical glass substrate, O represents air, and A represents the Al layer, which serves as the main reflective layer 2. L represents the MgF2 layer 31, and H represents the Al2O3 layer 32. The alternating stacked structure of the MgF2 layer 31 and the Al2O3 layer 32 serves as the dielectric enhancement layer. Furthermore, a represents a physical thickness of 180 nm, b represents a physical thickness of 26.43 nm, and c represents a physical thickness of 36.65 nm.

[0065] In this embodiment, the method for preparing the 190-230nm metallic dielectric enhanced reflective film includes the following steps:

[0066] S1. Polish the surface of the K9 optical glass substrate with a polishing solution prepared by mixing iron oxide powder and anhydrous ethanol using a degreased cotton swab; then wipe the polished K9 optical glass substrate with a mixture of anhydrous ethanol and ether using a degreased cotton swab to remove surface residue, thus obtaining a double-sided polished K9 optical glass substrate material; wherein, the weight ratio of iron oxide powder to anhydrous ethanol in the polishing solution is 1:50, and the weight ratio of anhydrous ethanol to ether in the mixture of anhydrous ethanol and ether is 1:3.

[0067] S2, with an initial vacuum of 2.0 × 10⁻⁶ -4 The double-sided polished K9 optical glass substrate material was baked in an environment with a temperature of 100°C and a pressure of Pa.

[0068] S3. Al is vapor-deposited on the surface of the baked double-sided polished K9 optical glass substrate material. The evaporation rate of Al is 3.0 nm / s, thereby forming the main reflective layer 2.

[0069] S4. MgF2 and Al2O3 are alternately deposited once each on the surface of the main radiating layer 2. The evaporation rate of MgF2 is 0.8 nm / s and the evaporation rate of Al2O3 is 0.5 nm / s, thereby forming the dielectric reinforcement layer 3 and obtaining a metal dielectric reinforced reflective film with a wavelength of 190-230 nm.

[0070]

Example 2

[0071] A metallic dielectric enhanced reflective film with a wavelength of 190-230nm, differing from [Example 1] in that: (Refer to...) Figure 2 The metallic dielectric enhanced reflective film includes a substrate 1, a main reflective layer 2, and two dielectric enhancement layers 3. The specific film layer design structure is: Sub / aAbLcHdLeH / O, where a represents a physical thickness of 180nm, b and d represent physical thicknesses of 26.43nm, and c and e represent physical thicknesses of 36.65nm.

[0072]

Example 3

[0073] A metallic dielectric enhanced reflective film with a wavelength of 190-230nm, differing from [Example 1] in that: (Refer to...) Figure 3 The metallic dielectric enhanced reflective film includes a substrate 1, a main reflective layer 2, and a three-layer dielectric enhancement layer 3. The specific film layer design structure is: Sub / aAbLcHdLeHfLgH / O, where a represents a physical thickness of 180nm, b, d, and f represent physical thicknesses of 26.43nm, and c, e, and g represent physical thicknesses of 36.65nm.

[0074] Comparative Example

[0075] Comparative Example 1

[0076] A metallic dielectric enhanced reflective film with a wavelength of 190-230nm differs from [Example 2] in that: in step S3, the evaporation rate of Al is 6.5nm / s.

[0077] Comparative Example 2

[0078] A metallic dielectric enhanced reflective film with a wavelength of 190-230nm differs from [Example 2] in that the evaporation rate of Al2O3 in step S4 is 1.5nm / s.

[0079] Comparative Example 3

[0080] A metallic dielectric enhanced reflective film with a wavelength of 190-230nm differs from [Example 2] in that the evaporation rate of MgF2 in step S4 is 1.8nm / s.

[0081] Comparative Example 4

[0082] A metallic dielectric enhanced reflective film differs from [Example 2] in that the physical thickness of each layer is different.

[0083] The physical thickness represented by 'a' is 156 nm, the physical thicknesses represented by 'b' and 'd' are 35.13 nm, and the physical thicknesses represented by 'c' and 'e' are 42.69 nm.

[0084] Comparative Example 5

[0085] A metallic dielectric enhanced reflective film differs from [Example 2] in that the physical thickness of each layer is different.

[0086] The physical thickness represented by 'a' is 204 nm, the physical thicknesses represented by 'b' and 'd' are 20.13 nm, and the physical thicknesses represented by 'c' and 'e' are 23.69 nm.

[0087] Comparative Example 6

[0088] A metallic dielectric enhanced reflective film differs from [Example 2] in that it does not have a main reflective layer Al layer. The specific film layer design structure is: Sub / bLcHdLeH / O, where b and d represent physical thicknesses of 26.43 nm and c and e represent physical thicknesses of 36.65 nm.

[0089] Comparative Example 7

[0090] A metallic dielectric enhanced reflective film differs from [Example 2] in that: the MgF2 layer 31 is replaced by an Al2O3 layer 32 of the same thickness, that is, the specific film layer design structure is: Sub / aAbHcHdHeH / O, where a represents a physical thickness of 180nm, b and d represent physical thicknesses of 26.43nm and c and e represent physical thicknesses of 36.65nm respectively.

[0091] Comparative Example 8

[0092] A metallic dielectric enhanced reflective film differs from [Example 2] in that: the Al2O3 layer 32 is replaced by a MgF2 layer 31 of the same thickness, that is, the specific film layer design structure is: Sub / aAbLcLdLeL / O, where a represents a physical thickness of 180nm, b and d represent physical thicknesses of 26.43nm, and c and e represent physical thicknesses of 36.65nm.

[0093] Comparative Example 9

[0094] A metallic dielectric enhanced reflective film differs from [Example 2] in that the dielectric enhancement layer 3 has 4 layers, i.e., the specific film layer design structure is: Sub / aAbLcHdLeHfLgHhLiH / O, where a represents a physical thickness of 180nm, b, d, f, and h represent physical thicknesses of 26.43nm, and c, e, g, and i represent physical thicknesses of 36.65nm.

[0095] Performance testing

[0096] Reflectivity: The reflectivity of the metallic dielectric enhanced reflective film in each embodiment and comparative example in the range of 190-230 nm was measured using a spectral reflectivity meter with an incident angle of 0°. The minimum and peak values ​​of reflectivity were recorded.

[0097] Cross-cut test: The test shall be conducted in accordance with Section 7 of GB / T 26332.4-2015. The tape pulling speed shall be 30 mm / s. The adhesion level of the film layer shall be recorded according to the evaluation system in the standard. The lower the adhesion level, the higher the bonding strength between the film layers.

[0098] Table 1

[0099]

[0100] The difference between Example 2 and Example 1 is that the dielectric enhancement layer in Example 2 is two-layered. As shown in Table 1, adding a dielectric enhancement layer in Example 2 further improves the reflectivity of the dielectric enhancement film.

[0101] The difference between Comparative Example 1 and Example 2 is that in the metal dielectric enhanced reflective film of Comparative Example 1, the evaporation rate of Al in the Al layer is too high. According to the data in Table 1, when the evaporation rate of Al is too high, it is easy to cause the bonding strength between adjacent film layers of the metal dielectric enhanced reflective film to decrease, which is not conducive to improving the durability of the metal dielectric enhanced reflective film.

[0102] The difference between Comparative Example 2 and Example 2 is that in the metal dielectric enhanced reflective film of Comparative Example 2, the evaporation rate of Al2O3 in the Al2O3 layer is too high. According to the data in Table 1, when the evaporation rate of Al2O3 is too high, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm wavelength range will easily decrease, and the reflectivity of the metal dielectric enhanced film in the 190-230nm wavelength range cannot reach more than 90%. At the same time, the bonding strength between adjacent film layers will decrease, which is not conducive to improving the durability of the metal dielectric enhanced reflective film.

[0103] The difference between Comparative Example 3 and Example 2 is that in the metal dielectric enhanced reflective film of Comparative Example 3, the evaporation rate of MgF2 in the MgF2 layer is too high. According to the data in Table 1, when the evaporation rate of MgF2 is too high, it is easy to cause a decrease in the reflectivity of the metal dielectric enhanced reflective film. The reflectivity of the metal dielectric enhanced film in the 190-230nm wavelength range cannot reach more than 90%. At the same time, the bonding strength between adjacent film layers decreases, which is not conducive to improving the durability of the metal dielectric enhanced reflective film.

[0104] The difference between Comparative Example 4 and Example 2 is that in the metal dielectric enhanced reflective film of Comparative Example 4, the physical thickness of the Al layer is reduced, while the physical thicknesses of the MgF2 and Al2O3 layers are increased. According to the data in Table 1, after the Al layer thickness is reduced and the MgF2 and Al2O3 layer thicknesses are increased, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm wavelength range decreases, and the reflectivity of the metal dielectric enhanced film in the 190-230nm wavelength range cannot consistently reach over 90%.

[0105] The difference between Comparative Example 5 and Example 2 is that in the metal dielectric enhanced reflective film of Comparative Example 5, the physical thickness of the Al layer is increased, while the physical thicknesses of the MgF2 layer and the Al2O3 layer are decreased. According to the data in Table 1, after increasing the thickness of the Al layer and decreasing the thicknesses of the MgF2 layer and the Al2O3 layer, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm wavelength range decreases, and the reflectivity of the metal dielectric enhanced film in the 190-230nm wavelength range cannot consistently reach above 90%.

[0106] The difference between Comparative Example 6 and Example 2 is that the metal dielectric enhanced reflective film in Comparative Example 6 does not have a primary reflective layer (Al layer). According to the data in Table 1, without the primary reflective layer (Al layer), the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm wavelength range decreases significantly, and the reflectivity of the metal dielectric enhanced film in the 190-230nm wavelength range cannot consistently reach over 90%.

[0107] The difference between Comparative Example 7 and Example 2 is that in Comparative Example 7, the MgF2 layer was replaced with an Al2O3 layer of the same thickness. According to the data in Table 1, after replacing the MgF2 layer with an Al2O3 layer of the same thickness, the reflectivity of the metal-dielectric enhanced reflective film in the 190-230nm wavelength range also decreased, and the reflectivity of the metal-dielectric enhanced film in the 190-230nm wavelength range could not consistently reach over 90%.

[0108] The difference between Comparative Example 8 and Example 2 is that in the metal dielectric enhanced reflective film of Comparative Example 8, the Al2O3 layer is replaced by a MgF2 layer of the same thickness. According to the data in Table 1, after replacing the Al2O3 layer with a MgF2 layer of the same thickness, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm wavelength range also decreases, and the reflectivity of the metal dielectric enhanced film in the 190-230nm wavelength range cannot consistently reach above 90%.

[0109] The difference between Comparative Example 9 and Examples 1-3 is that the number of dielectric reinforcement layers in Comparative Example 9 is greater than 3. According to the data in Table 1, when the number of dielectric reinforcement layers is too large, the reflectivity of the metal dielectric reinforcement film in the 190-230nm wavelength range cannot reach more than 90%.

[0110] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a metallic dielectric enhanced reflective film with a wavelength of 190-230 nm, characterized in that, Includes the following steps: The surface of the substrate (1) was polished using a polishing solution prepared with iron oxide powder and anhydrous ethanol; then the polished substrate (1) was wiped with a mixture of anhydrous ethanol and ether to remove surface residue and obtain a double-sided polished substrate material; the substrate (1) was made of optical glass K9 or BK7. The polished substrate (1) was baked. During the baking process, the temperature was controlled at 100±5℃ and the vacuum degree was controlled at 1.8×10. -4 Pa -2.2×10 -4 Pa; Al is vapor-deposited on the surface of the baked substrate (1) to form a main reflective layer (2); the main reflective layer (2) is an Al layer, and the evaporation rate of Al is 3.0±0.1nm / s when the Al layer is vapor-deposited. MgF2 and Al2O3 are alternately vapor-deposited twice on the surface of the main reflective layer (2) to form two dielectric enhancement layers (3), thereby obtaining a metal dielectric enhanced reflective film with a wavelength of 190-230nm; wherein, the dielectric enhancement layer is composed of a MgF2 layer (31) and an Al2O3 layer (32); The physical thickness of the Al layer is 180±2%nm, the physical thickness of the MgF2 layer (31) is 26.43±2%nm, and the physical thickness of the Al2O3 layer (32) is 36.65±2%nm; and when the MgF2 layer (31) is deposited, the evaporation rate of MgF2 is 0.8±0.1nm / s, and when the Al2O3 layer (32) is deposited, the evaporation rate of Al2O3 is 0.5±0.05nm / s; in addition, when depositing Al, MgF2 and Al2O3, the temperature is controlled at 100±2℃, and the vacuum degree is greater than 9.0*10 -3 Pa.

2. A 190-230nm wavelength metallic dielectric enhanced reflective film prepared by the method described in claim 1.

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