Metal medium enhanced reflecting film with wavelength of 190-230nm and preparation method thereof

Abstract

The invention relates to the technical field of optical thin films, in particular to a 190-230nm-wavelength metal dielectric enhanced reflecting film and a preparation method thereof.The metal dielectric enhanced reflecting film comprises a substrate, a main reflecting layer and a plurality of dielectric enhanced layers, the main reflecting layer is an Al layer, the dielectric enhanced layers are formed by alternately stacking MgF2 layers and Al2O3 layers, the number of the dielectric enhanced layers is not larger than 3, and the thickness of the dielectric enhanced layers is not larger 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, and 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, and in the Al2O3 layer, the evaporation rate of Al2O3 is 0.5 + / -0.05 nm / s. The metal medium enhanced reflecting film has stable high reflectivity in the wave band of 190-230nm, the compactness and firmness between the film layers are high, and the durability is good.

Description

Technical Field

[0001] The present application relates to the technical field of optical thin films, and in particular to a metal medium enhanced reflection film with a wavelength of 190-230nm and a preparation method thereof. Background Art

[0002] In optical systems, metal dielectric enhanced reflective film is a composite optical film that combines metal and dielectric materials. It is used to improve the reflectivity of light and control the path of light. This film is usually composed of one or more layers of high-reflectivity 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 properties of the film.

[0003] However, the reflectivity of the current metal dielectric enhanced reflective film in the wavelength range of 190-230nm is usually less than 85%. When used in gas concentration detection equipment, there is a problem of low detection accuracy, especially for low-concentration gas detection. In addition, in the metal dielectric enhanced reflective film, the bonding strength between the film layers affects the durability of the metal dielectric enhanced film, so it is necessary to provide a metal dielectric enhanced reflective film with high reflectivity and high bonding strength between the films. Summary of the invention

[0004] The purpose of this application is to overcome the above technical problems and provide a metal medium enhanced reflection film with a wavelength of 190-230nm and a preparation method thereof.

[0005] In the first aspect, the present application provides a 190-230nm wavelength metal dielectric enhanced reflective film using the following technical solution: A metal dielectric enhanced reflective film with a wavelength of 190-230nm, the metal dielectric enhanced reflective film comprising a substrate, a main reflective layer and a plurality of dielectric enhanced layers arranged in sequence, the main reflective layer being an Al layer, the dielectric enhanced layer being composed of MgF2 layers and Al2O3 layers alternately stacked, wherein the number of dielectric enhanced layers is no 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, and the physical thickness of the Al2O3 layer is 36.65±2%nm; and in the Al layer, the evaporation rate of Al is 3.0±0.1nm / s, in the MgF2 layer, the evaporation rate of MgF2 is 0.8±0.1nm / s, and in the Al2O3 layer, the evaporation rate of Al2O3 is 0.5±0.05nm / s.

[0006] By adopting the above technical solution, the Al layer is used as the main reflection layer. Since the absorption rate of Al in the ultraviolet band is low, efficient reflection can be achieved; at the same time, MgF2 layers and Al2O3 layers are alternately stacked as dielectric enhancement layers. Both MgF2 and Al2O3 materials show 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. In addition, the number of dielectric enhancement layers, the thickness control of the Al layer, the MgF2 layer and the Al2O3 layer, and the evaporation rates of the three materials Al, MgF2 and Al2O3 will also significantly affect the reflectivity and inter-film bonding strength of the metal dielectric enhanced reflective film. In this application, the number of dielectric enhancement layers is controlled within 1-3 layers, the physical thickness of the Al layer is controlled within the range of 180±2%nm, the physical thickness of the MgF2 layer is controlled within the range of 26.43±2%nm, and the physical thickness of the Al2O3 layer is controlled within the range of 36.65±2%nm. At the same time, through the coordination of the evaporation rates of Al, MgF2 and Al2O3, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm band can reach more than 90%, which can effectively improve the detection accuracy of gas concentration and can be applied to the detection of low-concentration gas. At the same time, in the metal dielectric enhanced reflective film, the bonding strength between the film layers is high, and the metal dielectric enhanced reflective film has good wear resistance and durability.

[0007] In some specific embodiments, the film layer design structure of the metal dielectric enhanced reflective film is Sub / aAbLcHdLeH / O, wherein 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.

[0008] 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 enhanced layers is 2. Among them, 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 obtain a reflectivity of more than 94% in the ultraviolet band of 190-230nm while taking into account the cost issue. When 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.

[0009] In some specific embodiments, the substrate is made of optical glass K9 or BK7.

[0010] 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 range of 190-230nm, and can effectively improve the flatness and stability of the film layer, thereby improving the overall optical performance of the metal dielectric enhanced reflective film.

[0011] In the second aspect, the present application provides a method for preparing a metallic medium enhanced reflective film with a wavelength of 190-230nm, which adopts the following technical solution: A method for preparing a metal dielectric enhanced reflective film with a wavelength of 190-230nm, comprising the following steps: Vapor depositing Al on the surface of the substrate to form a main reflective layer; MgF2 and Al2O3 are alternately deposited on the surface of the main radiation layer in sequence, thereby forming a dielectric enhancement layer to obtain a metal dielectric enhanced reflection film with a wavelength of 190-230nm.

[0012] By adopting the above technical scheme, the preparation method can form a main reflection layer and a dielectric enhancement layer on the surface of the substrate, wherein the main reflection layer is composed of an Al layer, and the dielectric enhancement layer is composed of alternating MgF2 layers and Al2O3 layers. The reflectivity of the finally obtained metal dielectric enhanced reflection film in the ultraviolet band range of 190-230nm reaches more than 90%, and it has excellent mechanical and optical properties.

[0013] In some specific embodiments, when Al, MgF2 and Al2O3 are evaporated, the temperature is controlled to be 100±2°C and the vacuum degree is greater than 9.0*10 -3 Pa.

[0014] By adopting the above technical solution, at high temperature 100±2℃ and high vacuum greater than 9.0×10 -3 The evaporation of Al, MgF2 and Al2O3 in the Pa environment can significantly improve the density and adhesion of the film layer, reduce the film layer's absorption of specific ultraviolet bands, and effectively solve the stress problem between film layers, making the film layer more solid, thereby improving the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm ultraviolet band.

[0015] In some specific implementations, the substrate is baked before Al is evaporated.

[0016] In some specific embodiments, during the baking process, the temperature is controlled at 100±5°C and the vacuum degree is controlled at 1.8×10 -4 Pa-2.2×10 -4 Pa.

[0017] By adopting the above technical solution, the substrate is pre-treated by baking, and the temperature is controlled to be 100±5℃ and the vacuum degree is 1.8×10 -4 Pa-2.2×10 -4 Pa can effectively improve the cleanliness and surface activity of the substrate, enhance the adhesion between the subsequent evaporated film layer and the substrate, and thus improve the stability and reflective performance of the metal medium enhanced reflective film.

[0018] In some specific implementations, before baking the substrate, the surface of the substrate is polished with a polishing liquid.

[0019] By adopting the above technical solution, before baking the substrate, the surface of the substrate is first polished with a polishing liquid, which effectively improves the smoothness of the substrate surface and ensures the bonding strength between the subsequent coating layer and the substrate, thereby improving the overall stability and optical performance of the film layer.

[0020] In some specific embodiments, the polishing process comprises the following steps: The substrate surface is polished with a polishing liquid prepared with iron oxide powder and anhydrous ethanol; then the polished substrate is wiped with a mixed liquid of anhydrous ethanol and ether to remove residual dirt on the surface, thereby obtaining a double-sided polished substrate material.

[0021] By adopting the above technical solution, residual dirt on the substrate surface is effectively removed, the smoothness and cleanliness of the substrate surface are improved, the bonding force between the film layer and the substrate is enhanced, which is beneficial to improving the overall stability and optical performance of the film layer.

[0022] In summary, the present application includes at least one of the following beneficial technical effects: By using Al (aluminum) as the main reflective layer material, and coordinating with MgF2 and Al2O3 as the dielectric enhancement layer, and controlling the number of dielectric enhancement layers to be no more than 3 layers, the reflectivity of the film in the ultraviolet band of 190-230nm reaches Ravg ≥ 90%, which significantly improves the reflectivity of the metal dielectric enhanced reflective film in the ultraviolet band of 190-230nm. When the metal dielectric enhanced reflective film is used in gas detection equipment, it can effectively improve the detection accuracy of gas concentration and can be applied to the detection of low-concentration gas; Through high-temperature high-vacuum coating method and specific evaporation rate, the film layer is prepared in a high-vacuum environment, which reduces the absorption of ultraviolet band and effectively solves the stress problem between film layers, improves the density and firmness of the film layer, and enhances the durability of the film layer; A specific substrate cleaning pre-treatment method is used to improve the smoothness of the substrate surface, ensure stronger adhesion between the film layer and the substrate, and further improve the mechanical properties and service life of the overall film layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the metal medium enhanced reflective film in Example 1 of the present application.

[0024] Figure 2 This is a schematic diagram of the structure of the metal medium enhanced reflective film in Example 2 of the present application.

[0025] Figure 3 This is a schematic diagram of the structure of the metal medium enhanced reflective film in Example 3 of the present application.

[0026] Figure 4 This is a reflectivity curve diagram of the metal medium enhanced reflective film in Example 1 of the present application.

[0027] Figure 5 This is a reflectivity curve diagram of the metal medium enhanced reflective film in Example 2 of the present application.

[0028] Figure 6 This is a reflectivity curve diagram of the metal medium enhanced reflective film in Example 3 of the present application.

[0029] Figure 7 This is a reflectivity curve diagram of the metal medium enhanced reflective film in comparative example 1 of the present application.

[0030] Figure 8 This is a reflectivity curve diagram of the metal medium enhanced reflective film in Comparative Example 2 of the present application.

[0031] Fig. 9 This is a reflectivity curve diagram of the metal medium enhanced reflective film in comparative example 3 of the present application.

[0032] Fig.10 This is a reflectivity curve diagram of the metal medium enhanced reflective film in comparative example 4 of the present application.

[0033] Fig.11 This is a reflectivity curve diagram of the metal medium enhanced reflective film in comparative example 5 of the present application.

[0034] Fig.12 This is a reflectivity curve diagram of the metal medium enhanced reflective film in Comparative Example 6 of the present application.

[0035] Fig.13 This is a reflectivity curve diagram of the metal medium enhanced reflective film in comparative example 7 of the present application.

[0036] Fig.14 This is a reflectivity curve diagram of the metal medium enhanced reflective film in Comparative Example 8 of the present application.

[0037] Fig.15 This is a reflectivity curve diagram of the metal medium enhanced reflective film in comparative example 9 of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 1. Substrate; 2. Main reflection layer; 3. Dielectric enhancement layer; 31. MgF2 layer; 32. Al2O3 layer. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings.

[0040] The inventor of this application found that in the field of optics, in order to obtain a metal dielectric enhanced reflective film with high reflectivity in the ultraviolet band (190-230nm), it is difficult to achieve a stable high reflectivity in a specific ultraviolet band due to the limitations of existing film layer design, coating process and film material selection. To this end, this application mainly adopts the following scheme to achieve a reflectivity of not less than 90% in the ultraviolet band (190-230nm). The following is a further detailed description of this application. Figure 1 and Figure 2 The present application provides a 190-230nm wavelength metal dielectric enhanced reflective film comprising a substrate 1, a main reflective layer 2 and a dielectric enhanced layer 3, wherein the main reflective layer 2 is an Al layer, and the dielectric enhanced layer 3 is composed of MgF2 layers 31 and Al2O3 layers 32 alternately stacked.

[0041] The preferred metal dielectric enhanced reflective film layer design structure is: Sub / aAbLcHdLeH / O, where Sub represents a BK7 or K9 optical glass substrate 1, O represents air, A represents an Al layer, L represents a MgF2 layer 31, H represents an 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.

[0042] Since the reflection band required by the present application is 190-230 nm and the reflectivity requirement is relatively high, an Al (aluminum) layer is selected to serve as the main reflection layer 2 because the absorption rate of Al in this ultraviolet band is relatively low.

[0043] The dielectric enhancement layer 3 uses an alternating stacking structure of MgF2 layers 31 and Al2O3 layers 32, wherein the transmittance of the MgF2 material is in the range of 100-800nm, and can reach more than 80% at 170nm, and the transmittance of the Al2O3 material can reach more than 70-85% in the wavelength range of 200-800nm, and can reach more than 90% at 200nm. Both MgF2 and Al2O3 materials have excellent performance and high transmittance in the ultraviolet band, can play a role in anti-reflection, and further improve the reflectivity of the metal dielectric enhanced reflective film in the range of 190-230nm.

[0044] The present application provides a method for preparing a metallic medium enhanced reflective film with a wavelength of 190-230 nm, comprising the following steps: The initial vacuum degree was 1.8×10 -4 Pa-2.2×10 -4 Baking the substrate in an environment of 100°C ± 2°C; Al is evaporated on the surface of the baked substrate 1 to form a main reflective layer 2; MgF2 and Al2O3 are alternately deposited on the surface of the main radiation layer 2 in sequence, thereby forming a dielectric enhancement layer 3 and obtaining a metal dielectric enhanced reflection film with a wavelength of 190-230nm.

[0045] When evaporating Al, MgF2 and Al2O3, the coating process starts after the temperature is kept constant at 100±2℃ for 30 minutes. The vacuum degree is maintained at more than 9.0*10 -3 Pa. Among them, the high vacuum environment can reduce the absorption of the metal dielectric enhanced reflective film to the ultraviolet band within the range of 190-230nm, while the high temperature environment effectively solves the stress problem between the film layers, improves the density of the film layer, makes the film layer more solid and has a longer life, improves the environmental durability of the metal dielectric enhanced reflective film, and can effectively maintain the surface finish of the substrate, thus obtaining a metal dielectric reflective film with excellent optical properties, strong film adhesion and friction resistance.

[0046] The control of the conditions during the film preparation is very critical. The preparation conditions of each film layer not only affect the compactness and other properties of the single film layer, but also affect the bonding strength with the adjacent film layer and the optical properties of the overall film layer. Among them, the selection of the material evaporation rate is particularly important. Through long-term research and development practice, the inventor of this application found that in this film system, when the evaporation rate of Al is 3.0±0.1nm / s, the evaporation rate of MgF2 is 0.8±0.1nm / s, and the evaporation rate of Al2O3 is 0.5±0.05nm / s, the compactness of the obtained film layer and the bonding strength with the adjacent film layer are optimal.

[0047] In addition, in order to better ensure adhesion, the substrate 1 is cleaned before coating, and the cleaning steps are as follows: The surface of the substrate 1 is polished with a cotton swab dipped in a polishing liquid prepared with iron oxide powder and anhydrous ethanol; then the polished substrate 1 is wiped with a cotton swab dipped in a mixture of anhydrous ethanol and ether to remove residual dirt on the surface, thereby obtaining a double-sided polished substrate material; wherein the weight ratio of iron oxide powder to anhydrous ethanol in the polishing liquid 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).

[0048] By pre-treating the substrate 1, especially strictly controlling the cleaning process, the high adhesion and smoothness of the film layer before coating are ensured. The cleaning step not only effectively removes dust and impurities on the surface of the substrate 1, but also provides an ideal surface for the subsequent evaporation process. Combined with the material selection and process optimization in the above embodiment, the entire metal medium enhanced reflective film not only achieves the expected effect in terms of reflectivity, but also has a significant improvement in mechanical properties, meeting the needs of high-end optical equipment.

[0049] The present application is further described below in conjunction with specific experiments.

[0050] [Example 1] A metal dielectric enhanced reflective film, referring to Figure 1 The metal dielectric enhanced reflective film includes 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 a K9 optical glass substrate, O represents air, A represents an Al layer, and the Al layer serves as the main reflective layer 2. L represents a MgF2 layer 31, and H represents an Al2O3 layer 32. The alternating stacking structure of the MgF2 layer 31 and the Al2O3 layer 32 serves as a dielectric enhancement layer. In addition, the physical thickness represented by a is 180 nm, the physical thickness represented by b is 26.43 nm, and the physical thickness represented by c is 36.65 nm.

[0051] In this embodiment, the method for preparing the metallic medium enhanced reflective film with a wavelength of 190-230 nm comprises the following steps: S1. Polishing the surface of a K9 optical glass substrate with a cotton swab dipped in a polishing liquid prepared with iron oxide powder and anhydrous ethanol; then wiping the polished K9 optical glass substrate with a cotton swab dipped in a mixture of anhydrous ethanol and ether to remove residual dirt on the surface, thereby obtaining a double-sided polished K9 optical glass substrate material; wherein the weight ratio of iron oxide powder to anhydrous ethanol in the polishing liquid is 1:50, and the weight ratio of anhydrous ethanol to ether in the mixture of anhydrous ethanol and ether is 1:3; S2, at the initial vacuum degree of 2.0×10 -4 The double-sided polished K9 optical glass substrate material is baked in an environment of 100°C. S3, evaporating Al on the surface of the double-sided polished K9 optical glass substrate material after baking, with the evaporation rate of Al being 3.0 nm / s, thereby forming a main reflective layer 2; S4. MgF2 and Al2O3 are alternately evaporated on the surface of the main radiation layer 2 once each, with the evaporation rate of MgF2 being 0.8nm / s and the evaporation rate of Al2O3 being 0.5nm / s, thereby forming a dielectric enhancement layer 3 and obtaining a metal dielectric enhanced reflection film with a wavelength of 190-230nm.

[0052] [Example 2] A metal dielectric enhanced reflective film with a wavelength of 190-230nm, which is different from [Example 1] in that: Figure 2 The metal dielectric enhanced reflective film includes a substrate 1, a main reflective layer 2 and two dielectric enhanced layers 3. The specific film layer design structure is: Sub / aAbLcHdLeH / O, where a represents a physical thickness of 180 nm, b and d represent physical thicknesses of 26.43 nm respectively, and c and e represent physical thicknesses of 36.65 nm respectively.

[0053] [Example 3] A metal dielectric enhanced reflective film with a wavelength of 190-230nm, which is different from [Example 1] in that: Figure 3 The metal dielectric enhanced reflective film includes a substrate 1, a main reflective layer 2 and a three-layer dielectric enhanced layer 3. The specific film layer design structure is: Sub / aAbLcHdLeHfLgH / O, where a represents a physical thickness of 180 nm, b, d, and f represent physical thicknesses of 26.43 nm, and c, e, and g represent physical thicknesses of 36.65 nm, respectively.

[0054] Comparative Example [Comparative Example 1] A metal dielectric enhanced reflective film with a wavelength of 190-230 nm, which differs from [Example 2] in that: in step S3, the evaporation rate of Al is 6.5 nm / s.

[0055] [Comparative Example 2] A metal dielectric enhanced reflective film with a wavelength of 190-230 nm, which differs from [Example 2] in that: in step S4, the evaporation rate of Al2O3 is 1.5 nm / s.

[0056] [Comparative Example 3] A metal dielectric enhanced reflective film with a wavelength of 190-230 nm, which differs from [Example 2] in that: in step S4, the evaporation rate of MgF2 is 1.8 nm / s.

[0057] [Comparative Example 4] A metal dielectric enhanced reflective film, which differs from [Example 2] in that the physical thickness of each layer is different.

[0058] The physical thickness represented by a is 156 nm, the physical thickness represented by b and d are 35.13 nm respectively, and the physical thickness represented by c and e are 42.69 nm respectively.

[0059] [Comparative Example 5] A metal dielectric enhanced reflective film, which differs from [Example 2] in that the physical thickness of each layer is different.

[0060] The physical thickness represented by a is 204 nm, the physical thickness represented by b and d are 20.13 nm respectively, and the physical thickness represented by c and e are 23.69 nm respectively.

[0061] [Comparative Example 6] A metal dielectric enhanced reflective film, which differs from [Example 2] in that: the main reflective layer Al layer is not set, that is, the specific film layer design structure is: Sub / bLcHdLeH / O, the physical thicknesses represented by b and d are 26.43nm respectively, and the physical thicknesses represented by c and e are 36.65nm respectively.

[0062] [Comparative Example 7] A metal dielectric enhanced reflective film, which 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, the physical thickness represented by a is 180nm, the physical thickness represented by b and d are 26.43nm respectively, and the physical thickness represented by c and e are 36.65nm respectively.

[0063] [Comparative Example 8] A metal dielectric enhanced reflective film, which differs from [Example 2] in that: the Al2O3 layer 32 is replaced by the MgF2 layer 31 of the same thickness, that is, the specific film layer design structure is: Sub / aAbLcLdLeL / O, a represents the physical thickness of 180nm, b and d represent the physical thicknesses of 26.43nm respectively, and c and e represent the physical thicknesses of 36.65nm respectively.

[0064] [Comparative Example 9] A metal dielectric enhanced reflective film, which differs from [Example 2] in that: the number of dielectric enhanced layers 3 is 4, that is, the specific film layer design structure is: Sub / aAbLcHdLeHfLgHhLiH / O, the physical thickness represented by a is 180nm, the physical thickness represented by b, d, f, and h are 26.43nm respectively, and the physical thickness represented by c, e, g, and i are 36.65nm respectively.

[0065] Performance testing Reflectivity: The reflectivity of the metal dielectric enhanced reflective film in each embodiment and comparative example at 190-230 nm was tested using a spectral reflectivity tester, with an incident angle of 0°, and the minimum and peak values ​​of the reflectivity were recorded.

[0066] Cross-hatch test: refer to Section 7 of GB / T 26332.4-2015 for testing. The tape is pulled up at a rate of 30 mm / s. The adhesion grade of the film layer is recorded according to the evaluation system in the standard. The lower the adhesion grade, the higher the bonding strength between the film layers.

[0067] Table 1

[0068] The difference between Example 2 and Example 1 is that there are two dielectric enhancement layers in the metal dielectric enhanced reflective film of Example 2. Combining the data in Table 1, it can be seen that after adding a dielectric enhancement layer in Example 2, the reflectivity of the metal dielectric enhanced reflective film can be further improved.

[0069] 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. Combined with the data in Table 1, it can be seen that 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.

[0070] 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. Combined with the data in Table 1, it can be seen that when the evaporation rate of Al2O3 is too high, it is easy to cause the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm band to decrease, and the reflectivity of the metal dielectric enhanced film in the 190-230nm band 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.

[0071] 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. Combined with the data in Table 1, it can be seen that when the evaporation rate of MgF2 is too high, it is easy to cause the reflectivity of the metal dielectric enhanced reflective film to decrease. The reflectivity of the metal dielectric enhanced film in the 190-230nm band 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.

[0072] 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, and the physical thickness of the MgF2 layer and the Al2O3 layer is increased. Combining the data in Table 1, it can be seen that after the thickness of the Al layer is reduced and the thickness of the MgF2 layer and the Al2O3 layer is increased, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm band is reduced, and the reflectivity of the metal dielectric enhanced film in the 190-230nm band cannot reach more than 90%.

[0073] 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 increases, and the physical thickness of the MgF2 layer and the Al2O3 layer decreases. Combining the data in Table 1, it can be seen that after the thickness of the Al layer increases and the thickness of the MgF2 layer and the Al2O3 layer decreases, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm band decreases, and the reflectivity of the metal dielectric enhanced film in the 190-230nm band cannot reach more than 90%.

[0074] The difference between Comparative Example 6 and Example 2 is that the main reflective layer Al layer is not provided in the metal dielectric enhanced reflective film of Comparative Example 6. Combined with the data in Table 1, it can be seen that after the main reflective layer Al layer is not provided, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm band is significantly reduced, and the reflectivity of the metal dielectric enhanced film in the 190-230nm band cannot reach more than 90%.

[0075] The difference between Comparative Example 7 and Example 2 is that in the metal dielectric enhanced reflective film of Comparative Example 7, the MgF2 layer is replaced by an Al2O3 layer of the same thickness. Combined with the data in Table 1, it can be seen that after the MgF2 layer is replaced by an Al2O3 layer of the same thickness, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm band also decreases, and the reflectivity of the metal dielectric enhanced film in the 190-230nm band cannot reach more than 90%.

[0076] 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. Combined with the data in Table 1, it can be seen that after the Al2O3 layer is replaced by a MgF2 layer of the same thickness, the reflectivity of the metal dielectric enhanced reflective film in the 190-230nm band also decreases, and the reflectivity of the metal dielectric enhanced film in the 190-230nm band cannot reach more than 90%.

[0077] The difference between Comparative Example 9 and Examples 1-3 is that the number of dielectric enhancement layers in Comparative Example 9 is greater than 3. Combined with the data in Table 1, it can be seen that the number of dielectric enhancement layers is too many, and the reflectivity of the metal dielectric enhancement film in the 190-230nm band cannot reach more than 90%.

[0078] This specific implementation manner is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the specific implementation manner as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A metal dielectric enhanced reflective film with a wavelength of 190-230nm, characterized in that: The metal dielectric enhanced reflective film comprises a substrate (1), a main reflective layer (2) and a plurality of dielectric enhanced layers (3) which are arranged in sequence, wherein the main reflective layer (2) is an Al layer, and the dielectric enhanced layer (3) is composed of MgF2 layers (31) and Al2O3 layers (32) which are alternately stacked, wherein the number of layers of the dielectric enhanced layer (3) is not greater than 3, 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 in the Al layer, the evaporation rate of Al is 3.0±0.1nm / s, in the MgF2 layer (31), the evaporation rate of MgF2 is 0.8±0.1nm / s, and in the Al2O3 layer (32), the evaporation rate of Al2O3 is 0.5±0.05nm / s.

2. The metal dielectric enhanced reflective film with a wavelength of 190-230 nm according to claim 1, characterized in that: The film layer design structure of the metal dielectric enhanced reflection film is Sub / aAbLcHdLeH / O, wherein Sub represents the substrate (1), O represents air, A represents the Al layer, L represents the MgF2 layer (31), H represents the Al2O3 layer (32), a represents the physical thickness of the Al layer, b and d represent the physical thickness of the MgF2 layer (31), and c and e represent the physical thickness of the Al2O3 layer (32).

3. The metal dielectric enhanced reflective film with a wavelength of 190-230 nm according to claim 1, characterized in that: The substrate (1) is made of optical glass K9 or BK7.

4. A method for preparing a metal dielectric enhanced reflective film with a wavelength of 190-230 nm, based on the metal dielectric enhanced reflective film with a wavelength of 190-230 nm as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: Vapor-depositing Al on the surface of the substrate (1) to form a main reflective layer (2); MgF2 and Al2O3 are alternately deposited on the surface of the main radiation layer (2) to form The type dielectric enhancement layer (3) is used to obtain a metallic dielectric enhanced reflection film with a wavelength of 190-230nm.

5. The method for preparing a metal dielectric enhanced reflective film with a wavelength of 190-230 nm according to claim 4, characterized in that: When evaporating Al, MgF2 and Al2O3, the temperature is controlled at 100±2℃ and the vacuum degree is greater than 9.0*10 -3 Pa.

6. The method for preparing a metal dielectric enhanced reflective film with a wavelength of 190-230 nm according to claim 4, characterized in that: Before Al is evaporated, the substrate (1) is baked.

7. The method for preparing a metallic dielectric enhanced reflective film with a wavelength of 190-230 nm according to claim 6, characterized in that: 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.

8. The method for preparing a metallic dielectric enhanced reflective film with a wavelength of 190-230 nm according to claim 6, characterized in that: Before baking the substrate (1), the surface of the substrate (1) is first polished using a polishing liquid.

9. The method for preparing a metallic dielectric enhanced reflective film with a wavelength of 190-230 nm according to claim 8, characterized in that: The polishing process comprises the following steps: The surface of the substrate (1) is polished using a polishing liquid prepared from iron oxide powder and anhydrous ethanol; the polished substrate (1) is then wiped with a mixture of anhydrous ethanol and ether to remove residual dirt on the surface, thereby obtaining a double-sided polished substrate material.

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