High-temperature-resistant optical filter and preparation method thereof

Abstract

The invention provides a high-temperature-resistant optical filter and a preparation method thereof. The high-temperature-resistant optical filter comprises a substrate, a first high-temperature-resistant film layer, an optical filter film layer and a second high-temperature-resistant film layer, and the first high-temperature-resistant film layer and the second high-temperature-resistant film layer comprise a plurality of SiO2 thin film layers and Al2O3 thin film layers which are sequentially arranged in a staggered mode; the SiO2 thin film layers and the Al2O3 thin film layers are alternately arranged, expansion or contraction of each thin film layer can be mutually compensated by the adjacent layers when the temperature changes, thermal stress between single layers can be offset to a certain degree, and therefore the sensitivity of the whole film system to the temperature changes is reduced, the thin film with high thermal stability is formed, and the service life of the thin film system is prolonged. The phenomenon that the optical filter film layer is broken, warped and even falls off and fails due to high temperature can be avoided under the high-temperature test of 600-1000 DEG C; the problems of substrate deformation, film layer failure, falling and the like possibly existing in a traditional optical filter in a high-temperature environment are solved in a targeted manner.

Description

Technical Field

[0001] The invention relates to the technical field of optical films, and in particular to a high temperature resistant filter and a preparation method thereof. Background Art

[0002] In the evolution of optical thin film technology, especially in the fields of laser lighting display, aerospace optical systems, high-temperature scientific research, energy, etc., the coefficient of thermal expansion (CTE) of thin film materials and the average distribution of thermal stress have become one of the key factors determining their heat resistance. When traditional filters are exposed to high temperature environments, the difference in the coefficient of thermal expansion between the film and the substrate material may cause a significant increase in thermal stress, and the tensile stress and tensile stress cannot be well matched to each other, causing a series of serious problems, such as substrate deformation, film performance degradation, and even film shedding failure, which seriously affects the stability and durability of the optical system.

[0003] Based on the defects of the current filters, it is necessary to improve them. Summary of the invention

[0004] In view of this, the present invention provides a high temperature resistant filter and a preparation method thereof to solve or at least partially solve the defects in the prior art.

[0005] In a first aspect, the present invention provides a high temperature resistant filter, comprising:

[0006] substrate;

[0007] The first high temperature resistant film layer is located on the surface of the substrate, and the first high temperature resistant film layer includes a plurality of first SiO 2 Thin film layer, first Al 2 O 3 Thin film layer;

[0008] A filter film layer, which is located on a surface of the first high temperature resistant film layer away from the substrate;

[0009] The second high temperature resistant film layer is located on the surface of the filter film layer away from the substrate, and the second high temperature resistant film layer includes a plurality of second SiO 2 Thin film layer, second Al 2 O 3 Thin film layer.

[0010] Preferably, the filter film layer comprises a plurality of Ta 2 O 5 Thin film layer, third SiO 2 Thin film layer.

[0011] Preferably, the substrate is a sapphire substrate.

[0012] Preferably, the first SiO 2 The thickness of the film layer is 50 to 120 nm;

[0013] The first Al 2 O 3 The thickness of the film layer is 20 to 30 nm;

[0014] The second SiO 2 The thickness of the film layer is 50 to 120 nm;

[0015] The second Al 2 O 3 The thickness of the film layer is 20 to 30 nm;

[0016] Said 2 O 5 The thickness of the film layer is 10 to 120 nm;

[0017] The third SiO 2 The thickness of the thin film layer is 10 to 150 nm.

[0018] Preferably, the first SiO 2 Thin film layer, first Al 2 O 3 The number of interleavings of the film layers is 1 to 1000 times;

[0019] Second SiO 2 Thin film layer, second Al 2 O 3 The number of interleavings of the film layers is 1 to 1000 times;

[0020] Ta 2 O 5 Thin film layer, third SiO 2 The number of interleavings of the film layers is 1 to 1000 times.

[0021] In a second aspect, the present invention further provides a method for preparing the high temperature resistant filter, comprising the following steps:

[0022] The first SiO 2 Thin film layer, first Al 2 O 3 Thin film layer, to prepare a first high temperature resistant film layer;

[0023] A filter film layer is prepared on the surface of the first high temperature resistant film layer;

[0024] The second SiO 2 Thin film layer, second Al 2 O 3The thin film layer is used to prepare a second high temperature resistant film layer.

[0025] Preferably, SiO 2 Particles, Al 2 O 3 The particles are used as evaporation sources, and the first SiO 2 Thin film layer, first Al 2 O 3 Thin film layer;

[0026] Among them, the first SiO 2 Thin film layer, first Al 2 O 3 When the film is layered, the substrate temperature is controlled at 250-260°C. 2 The deposition rate of the thin film layer is 0.2-0.3 nm / s. 2 O 3 The deposition rate of the thin film layer is 0.1-0.2 nm / s.

[0027] Preferably, the filter film layer comprises a plurality of Ta 2 O 5 Thin film layer, third SiO 2 Thin film layer;

[0028] The method of preparing a filter film layer on the surface of the first high temperature resistant film layer specifically includes the following steps:

[0029] Ta 2 O 5 Particles, SiO 2 The particles are used as evaporation sources, and Ta is deposited alternately on the surface of the first high temperature resistant film layer by electron beam thermal evaporation. 2 O 5 Thin film layer, third SiO 2 A thin film layer to prepare a filter film layer;

[0030] Among them, the deposition of Ta 2 O 5 Thin film layer, third SiO 2 When the thin film layer is formed, the substrate temperature is controlled at 250-260°C. 2 O 5 The deposition rate of the thin film layer is 0.2-0.4 nm / s. 2 The deposition rate of the thin film layer is 0.2-0.3 nm / s.

[0031] Preferably, SiO 2 Particles, Al 2 O 3The particles are used as evaporation sources, and the second SiO 2 Thin film layer, second Al 2 O 3 Thin film layer;

[0032] Among them, the second SiO 2 Thin film layer, second Al 2 O 3 When the thin film layer is formed, the substrate temperature is controlled at 250-260°C, and the second SiO 2 The deposition rate of the thin film layer is 0.2-0.3 nm / s, and the second Al 2 O 3 The deposition rate of the thin film layer is 0.1-0.2 nm / s.

[0033] Preferably, the first SiO 2 Thin film layer, first Al 2 O 3 Before the thin film layer is formed, the substrate is also subjected to plasma treatment, wherein the plasma treatment gas includes oxygen and argon, the oxygen flow rate is 50-60sccm, the argon flow rate is 8-10sccm, the plasma treatment time is 60-120s, the voltage is 700-710V, and the current is 700-710mA.

[0034] The high temperature resistant filter and the preparation method thereof of the present invention have the following beneficial effects compared with the prior art:

[0035] 1. The high temperature resistant filter of the present invention adopts a sapphire substrate combined with Al 2 O 3 Thin film layer, SiO 2 The film layers are arranged alternately to form a film structure with strong thermal stability. 2 O 3 Thin film layer, SiO 2 The film layers have a low coefficient of thermal expansion (CTE), which helps to reduce the thermal stress caused by temperature changes. In addition, Al 2 O 3 Thin film layer, SiO 2 The thin film layer has outstanding thermal stability and good high temperature resistance. 2 O 3 Thin film layer, SiO 2The expansion or contraction of each thin film layer when the temperature changes will be compensated by the adjacent layers, which can offset the thermal stress between the single layers to a certain extent, thereby reducing the sensitivity of the overall film system to temperature changes and forming a thin film with strong thermal stability, so that it can meet the high temperature test of 600-1000℃, avoiding the phenomenon of filter film layer breakage, warping, or even shedding failure caused by high temperature; targetedly solves the problems of substrate deformation, film failure, shedding, etc. that may exist in traditional filters under high temperature environment.

[0036] 2. The preparation method of the high temperature resistant filter of the present invention adopts the method of alternately depositing Al 2 O 3 Thin film layers and SiO 2 The film layer can form a good high temperature resistant film, and the periodic stacking helps to average out the uneven distribution of thermal stress in the film layer caused by thermal expansion, making Al 2 O 3 Thin film layers and SiO 2 The thermal stress of the thin film layer is evenly distributed in a high temperature range of 650°C or even wider, maintaining the filter characteristics; in order to be used under high temperature conditions of 650°C, the filter of the present invention adopts electron beam thermal evaporation and alternate deposition to form a protective layer SiO2 that can be separated from the external high temperature and the filter film layer. 2 +Al 2 O 3 High temperature resistant film ensures the precise optical screening capability of the filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0038] Figure 1 It is a schematic structural diagram of the high temperature resistant filter of the present invention;

[0039] Figure 2 The process flow chart of the preparation method of the high temperature resistant optical filter of the present invention;

[0040] Figure 3 This is a spectrum performance diagram of the high temperature resistant filter prepared in Example 1 at room temperature;

[0041] Figure 4 This is a real picture of the commercially available filter after a high temperature test at 650°C;

[0042] Figure 5This is a real picture of the high temperature resistant filter prepared in Example 1 after being subjected to a high temperature test at 650°C;

[0043] Figure 6 This is a spectral performance diagram of the high temperature resistant filter prepared in Example 1 after high temperature testing at 650°C. DETAILED DESCRIPTION

[0044] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] The following are described in detail. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and simplicity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered ranges, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any quoted numbers (fractions or integers) within the indicated range.

[0047] The present invention provides a high temperature resistant filter, such as Figure 1 As shown, including:

[0048] Base 1;

[0049] The first high temperature resistant film layer 2 is located on the surface of the substrate 1. The first high temperature resistant film layer 2 includes a plurality of first SiO 2 Thin film layer 21, first Al 2 O 3 Thin film layer 22;

[0050] The filter film layer 3 is located on the surface of the first high temperature resistant film layer 2 away from the substrate 1;

[0051] The second high temperature resistant film layer 4 is located on the surface of the filter film layer 2 away from the substrate 1. The second high temperature resistant film layer 4 includes a plurality of second SiO 2 Thin film layer 41, second Al 2 O 3 Thin film layer 42 .

[0052] The high temperature resistant filter of the present invention comprises a substrate 1, a first high temperature resistant film layer 2, a filter film layer 3, and a second high temperature resistant film layer 4. The first high temperature resistant film layer 22 comprises a plurality of first SiO 2 Thin film layer 21, first Al 2 O 3 The thin film layer 22, namely the first SiO 2 Thin film layer 21 / first Al 2 O 3 Thin film layer 22 / first SiO 2 Thin film layer 21 / first Al 2 O 3 The thin film layers 22 are arranged alternately in sequence; the second high temperature resistant film layer 4 comprises a plurality of second SiO 2 Thin film layer 41, second Al 2 O 3 The thin film layer 42, namely the second SiO 2 Thin film layer 41 / second Al 2 O 3 Thin film layer 42 / second SiO 2 Thin film layer 41 / second Al 2 O 3 The film layers 42 . . . are arranged in a staggered manner.

[0053] In a high temperature environment, the traditional optical filter often causes a significant increase in thermal stress due to the difference in thermal expansion coefficient between the film and the base material, thereby causing problems such as base deformation, film performance degradation, and even film shedding failure. These problems seriously affect the stability and durability of the optical system. This is because traditional optical filters may only use a single material or a simple multi-layer structure, without considering the use of alternate deposition of materials with different thermal expansion coefficients to offset thermal stress. In the high temperature resistant optical filter of the present invention, the first high temperature resistant film layer 2 includes a plurality of first SiO 2 Thin film layer 21, first Al 2 O 3 The second high temperature resistant film layer 4 includes a plurality of second SiO 2 Thin film layer 41, second Al 2 O 3 The thin film layer 42 is made of SiO 2 Thin film layer, Al 2O 3 The film layers are arranged alternately to form a film structure with strong thermal stability, because Al 2 O 3 With SiO 2 The thermal expansion coefficient of Al is low. Under high temperature test conditions of 600-1000℃, 2 O 3 Thin film layer and SiO 2 The tensile stress and tensile stress between the film layers can adapt and interact well, which is beneficial to reduce the thermal stress problems caused by temperature changes, ensure that the optical properties of the filter are not affected, and effectively avoid problems such as film shedding, cracks, deformation and even failure caused by high temperature testing.

[0054] Specifically, the Al of the present invention 2 O 3 The coefficient of thermal expansion (CTE) of the film layer is about (7-8)×10 -6 / K,SiO 2 The coefficient of thermal expansion (CTE) of the film layer is about 0.5×10 -6 / K,Al 2 O 3 Thin film layer, SiO 2 The film layers have a low coefficient of thermal expansion (CTE), which helps to reduce the thermal stress caused by temperature changes. In addition, Al 2 O 3 Thin film layer, SiO 2 The thin film layer has outstanding thermal stability and good high temperature resistance. The high temperature resistant filter of the present invention has excellent thermal stability and good high temperature resistance. 2 O 3 Thin film layer, SiO 2 The thermal expansion coefficients of the thin film layers are different, and the SiO 2 Thin film layer, Al 2 O 3 The expansion or contraction of each thin film layer when the temperature changes will be compensated by the adjacent layers, which can offset the thermal stress between the single layers to a certain extent, thereby reducing the sensitivity of the overall film system to temperature changes and forming a film with strong thermal stability, so that it can meet the high temperature test of 600-1000℃, avoiding the phenomenon of filter film layer breaking, warping, or even falling off due to high temperature. Specifically, for example, when the temperature rises, Al 2 O 3 The film layer expands relatively more, while SiO 2 The film layer expands less, SiO 2 The thin film layer will 2 O 3A certain tensile stress is applied to the thin film layer, and vice versa; this alternating stacking structure helps to reduce the sensitivity of the overall film system to temperature changes, allowing the thermal stress to be evenly distributed within a wider temperature range (such as 600-1000°C), thereby reducing the risk of film layer damage caused by thermal stress and the sensitivity of the overall film system to temperature changes, forming a thin film with strong thermal stability.

[0055] In some embodiments, the filter film layer 3 includes a plurality of Ta layers which are alternately arranged in sequence. 2 O 5 Thin film layer 31, third SiO 2 Thin film layer 32.

[0056] Specifically, 2 O 5 Thin film layer 31 / third SiO 2 Thin film layer 32 / Ta 2 O 5 Thin film layer 31 / third SiO 2 The film layers 32 . . . are arranged in a staggered manner.

[0057] In some embodiments, the substrate 1 is a sapphire substrate. Specifically, the coefficient of thermal expansion (CTE) of the sapphire substrate is about (7-8)×10 -6 / K, has a lower coefficient of thermal expansion (CTE), which is beneficial to reduce thermal stress problems caused by temperature changes. In addition, the sapphire substrate has outstanding thermal stability and good high temperature resistance.

[0058] In some embodiments, the first SiO 2 Thin film layer 21, first Al 2 O 3 Thin film layer 22, second SiO 2 Thin film layer 41, second Al 2 O 3 Thin film layer 42, Ta 2 O 5 Thin film layer 31, third SiO 2 The thickness and number of each layer of the thin film layer 32 can be precisely controlled according to its thermal expansion coefficient and the required overall performance, so as to disperse and alleviate the problem of thermal stress concentration, so that the optical filter can still maintain its stable optical performance in a high temperature environment and is not prone to oxidation decomposition and film shedding between the film layers.

[0059] In some embodiments, the first SiO 2 The thickness of the thin film layer 21 is 50-120 nm. Preferably, the first SiO 2 The thickness of the thin film layer 21 is 2 The thickness of the thin film layer is 87.90 to 99.97 nm.

[0060] In some embodiments, the first Al 2 O 3 The thickness of the thin film layer 22 is 20-30 nm. Preferably, the first Al 2 O 3 The thickness of the thin film layer 22 is 27.57-28.28 nm.

[0061] In some embodiments, the second SiO 2 The thickness of the thin film layer 41 is 50-120 nm. Preferably, the second SiO 2 The thickness of the thin film layer 41 is 70 to 80 nm, and more preferably 76.54 nm.

[0062] In some embodiments, the second Al 2 O 3 The thickness of the thin film layer 42 is 20-30 nm, preferably 20.56 nm.

[0063] In some embodiments, Ta 2 O 5 The thickness of the thin film layer 31 is 10 to 120 nm, preferably 16.53 to 117.33 nm.

[0064] In some embodiments, the third SiO 2 The thickness of the thin film layer 32 is 10 to 150 nm, preferably 15.91 to 134.19 nm.

[0065] In some embodiments, the first SiO 2 Thin film layer 21, first Al 2 O 3 The number of interlacing of the thin film layer 22 is 2; all first SiO 2 The total thickness of the thin film layer 21 is 187.87 nm; 2 O 3 The total thickness of the thin film layer 22 is 55.85 nm.

[0066] In some embodiments, the second SiO 2 Thin film layer 41, second Al 2 O 3 The number of interleavings of the thin film layer 42 is 1, and the second SiO 2 The thickness of the thin film layer 41 is 76.54 nm. 2 O 3 The thickness of the thin film layer 42 is 20.56 nm.

[0067] In some embodiments, Ta 2 O 5 Thin film layer 31, third SiO 2The number of interleavings of the thin film layer 32 is 23, all Ta 2 O 5 The total thickness of the thin film layer 31 is 1889.72nm. 2 The total thickness of the thin film layer 32 is 1634.54 nm.

[0068] Based on the same inventive concept, the present invention also provides a method for preparing the above-mentioned high temperature resistant filter, such as Figure 2 As shown, the following steps are included:

[0069] S1, deposit the first SiO 2 Thin film layer, first Al 2 O 3 Thin film layer, to prepare a first high temperature resistant film layer;

[0070] S2, preparing a filter film layer on the surface of the first high temperature resistant film layer;

[0071] S3, depositing the second SiO 2 Thin film layer, second Al 2 O 3 The thin film layer is used to prepare a second high temperature resistant film layer.

[0072] In some embodiments, SiO 2 Particles, Al 2 O 3 The particles are used as evaporation sources, and the first SiO 2 Thin film layer, first Al 2 O 3 Thin film layer;

[0073] Among them, the first SiO 2 Thin film layer, first Al 2 O 3 When the thin film layer is formed, the substrate temperature is controlled at 250-260°C. 2 The deposition rate of the thin film layer is 0.2-0.3 nm / s. 2 O 3 The deposition rate of the thin film layer is 0.1-0.2 nm / s; preferably, the substrate temperature is controlled to be 250°C, and the first SiO 2 The deposition rate of the thin film layer is 0.25nm / s, the first Al 2 O 3 The deposition rate of the thin film layer was 0.1 nm / s.

[0074] In some embodiments, the filter film layer includes a plurality of Ta layers arranged alternately in sequence. 2O 5 Thin film layer, third SiO 2 Thin film layer;

[0075] A filter film layer is prepared on the surface of the first high temperature resistant film layer, specifically comprising the following steps:

[0076] Ta 2 O 5 Particles, SiO 2 The particles are used as evaporation sources, and Ta is deposited alternately on the surface of the first high temperature resistant film layer by electron beam thermal evaporation. 2 O 5 Thin film layer, third SiO 2 A thin film layer to prepare a filter film layer;

[0077] Among them, the deposition of Ta 2 O 5 Thin film layer, third SiO 2 When the thin film layer is formed, the substrate temperature is controlled at 250-260°C. 2 O 5 The deposition rate of the thin film layer is 0.2-0.4 nm / s. 2 The deposition rate of the thin film layer is 0.2-0.3 nm / s; preferably, the substrate temperature is controlled to be 250°C, Ta 2 O 5 The deposition rate of the thin film layer is 0.3nm / s, and the third SiO 2 The deposition rate of the thin film layer was 0.25 nm / s.

[0078] In some embodiments, SiO 2 Particles, Al 2 O 3 The particles are used as evaporation sources, and the second SiO 2 Thin film layer, second Al 2 O 3 Thin film layer;

[0079] Among them, the second SiO 2 Thin film layer, second Al 2 O 3 When the thin film layer is formed, the substrate temperature is controlled at 250-260°C, and the second SiO 2 The deposition rate of the thin film layer is 0.2-0.3 nm / s. 2 O 3 The deposition rate of the thin film layer is 0.1-0.2 nm / s; preferably, the substrate temperature is controlled to be 250°C, and the second SiO 2 The deposition rate of the thin film layer is 0.25nm / s, and the second Al2 O 3 The deposition rate of the thin film layer was 0.1 nm / s.

[0080] In some embodiments, a first SiO 2 Thin film layer, first Al 2 O 3 Before the thin film layer is formed, the substrate is also subjected to plasma treatment, wherein the plasma treatment gas includes oxygen and argon, the oxygen flow rate is 50-60sccm, the argon flow rate is 8-10sccm, the plasma treatment time is 60-120s, the voltage is 700-710V, and the current is 700-710mA; preferably, the oxygen flow rate is 55sccm, the argon flow rate is 8sccm, the plasma treatment time is 60s, the voltage is 700V, and the current is 700mA.

[0081] In some embodiments, the method for preparing a high temperature resistant filter of the present invention comprises the following steps:

[0082] S1. Select high purity SiO 2 、Al 2 O 3 、 2 O 5 The particles are added into the evaporation crucible of the electron beam thermal evaporation coating machine;

[0083] S2. Use a mechanical pump and an oil diffusion pump to pump the vacuum chamber of the vacuum coating machine to a pressure less than 2×10 -3 Pa, use the heating wire to raise the temperature of the vacuum chamber to the set temperature of 250°C;

[0084] S3, 55 sccm oxygen is introduced into the RF ion source body, and 8 sccm argon is introduced into the ion source neutralizer to generate plasma to clean the sapphire substrate; the plasma treatment time is 60 s, the voltage is 700 V, and the current is 700 mA;

[0085] S4. After the sapphire substrate is cleaned, electron beam thermal evaporation is used to alternately deposit the first SiO 2 Thin film layer, first Al 2 O 3 The thin film layer is used to prepare a first high temperature resistant film layer;

[0086] Ta was obtained by electron beam thermal evaporation by sequentially depositing on the surface of the first high temperature resistant film layer. 2 O 5 Thin film layer, third SiO 2 A thin film layer to prepare a filter film layer;

[0087] The second SiO 2 Thin film layer, second Al 2 O 3 Thin film layer, to prepare a second high temperature resistant film layer;

[0088] S5. After the thin film deposition is completed, the vacuum chamber is cooled for 30 minutes to complete the preparation of the high temperature resistant filter.

[0089] In some embodiments, the prepared high temperature resistant filter is subjected to a high temperature test, and the test temperature is 650±30°C.

[0090] In some embodiments, the filter after high temperature testing is annealed to release the thermal stress accumulated on the filter, improve the mechanical properties of the high temperature resistant film, and prevent the film from cracking or falling off; the annealing temperature is 250°C and the time is 1 hour.

[0091] The preparation method of the high temperature resistant filter of the present invention innovatively adopts a sapphire substrate combined with aluminum oxide (Al 2 O 3 ) and silicon dioxide (SiO 2 ) alternating multilayer film design, sapphire, silicon dioxide (SiO 2 ) and aluminum oxide (Al 2 O 3 ) have relatively low thermal expansion coefficients and excellent thermal stability, which specifically solves the problems of substrate deformation, film failure, and shedding that may occur in traditional filters under high temperature environments; the use of alternating deposition of Al 2 O 3 Thin film layers and SiO 2 The film layer can form a good high temperature resistant film, and the periodic stacking helps to average out the uneven distribution of thermal stress in the film layer caused by thermal expansion, making Al 2 O 3 Thin film layers and SiO 2 The thermal stress of the thin film layer is evenly distributed in a high temperature range of 650°C or even wider, maintaining the filter characteristics; in order to be used under high temperature conditions of 650°C, the filter of the present invention adopts electron beam thermal evaporation and alternate deposition to form a protective layer SiO2 that can be separated from the external high temperature and the filter film layer. 2 +Al 2 O 3 High temperature resistant film ensures the precise optical screening capability of the filter.

[0092] The following further describes the high temperature resistant filter and its preparation method of the present application with specific examples. This section further describes the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0093] Example 1

[0094] The embodiment of the present application provides a high temperature resistant filter, including:

[0095] substrate;

[0096] The first high temperature resistant film layer is located on the surface of the substrate, and the first high temperature resistant film layer includes a plurality of first SiO 2 Thin film layer, first Al 2 O 3 Thin film layer;

[0097] A filter film layer, which is located on the surface of the first high temperature resistant film layer away from the substrate;

[0098] The second high temperature resistant film layer is located on the surface of the filter film layer away from the substrate. The second high temperature resistant film layer includes a plurality of second SiO 2 Thin film layer, second Al 2 O 3 Thin film layer;

[0099] The filter film layer includes a plurality of Ta 2 O 5 Thin film layer, third SiO 2 Thin film layer;

[0100] The substrate is a sapphire substrate;

[0101] First SiO 2 Thin film layer, first Al 2 O 3 The number of interleavings of the film layers is 2;

[0102] Second SiO 2 Thin film layer, second Al 2 O 3 The number of interleavings of the film layers is 1;

[0103] Ta 2 O 5 Thin film layer, third SiO 2 The number of interlacing times of the film layers is 23;

[0104] The thickness of each film layer is shown in Table 1 below:

[0105] Table 1 - Thickness of each film layer

[0106]

[0107]

[0108]

[0109] In Table 1, the 1st film layer to the 51st film layer represent the Figure 1 The upper surface of the middle substrate is composed of the first thin film layer, the second thin film layer, ... the 51st thin film layer from bottom to top; wherein the first thin film layer to the fourth thin film layer are the first SiO 2 Thin film layer, first Al 2 O 3 The film layer is staggered twice; the 5th to 50th film layers are Ta layers staggered in sequence. 2 O 5 Thin film layer, third SiO 2 The number of interlaced thin film layers is 23; the 50th to 51st thin film layers are the second SiO 2 Thin film layer, second Al 2 O 3 The thin film layer is interlaced once, and the 50th thin film layer is shared by the filter film layer and the second high temperature resistant film layer.

[0110] The method for preparing the above-mentioned high temperature resistant filter comprises the following steps:

[0111] S1. Select high purity SiO 2 、Al 2 O 3 、 2 O 5 The particles are added into the evaporation crucible of the electron beam thermal evaporation coating machine;

[0112] S2. Use a mechanical pump and an oil diffusion pump to pump the vacuum chamber of the vacuum coating machine to a pressure less than 2×10 -3 Pa, use the heating wire to raise the temperature of the vacuum chamber to the set temperature of 250°C;

[0113] S3, 55 sccm oxygen is introduced into the RF ion source body, and 8 sccm argon is introduced into the ion source neutralizer to generate plasma to clean the sapphire substrate; the plasma treatment time is 60 s, the voltage is 700 V, and the current is 700 mA;

[0114] S4. After the sapphire substrate is cleaned, electron beam thermal evaporation is used to alternately deposit the first SiO 2 Thin film layer, first Al 2 O3 The first SiO2 film layer is prepared to obtain a first high temperature resistant film layer; the substrate temperature is controlled to be 250°C, the first SiO2 film layer is 2 The deposition rate of the thin film layer is 0.25nm / s, the first Al 2 O 3 The deposition rate of the thin film layer is 0.1 nm / s;

[0115] Ta was obtained by electron beam thermal evaporation by sequentially depositing on the surface of the first high temperature resistant film layer. 2 O 5 Thin film layer, third SiO 2 The substrate temperature is controlled to be 250°C, Ta 2 O 5 The deposition rate of the thin film layer is 0.3nm / s, and the third SiO 2 The deposition rate of the thin film layer is 0.25 nm / s;

[0116] The second SiO 2 Thin film layer, second Al 2 O 3 The second high temperature resistant film layer is prepared by controlling the substrate temperature to 250°C. 2 The deposition rate of the thin film layer is 0.25nm / s, and the second Al 2 O 3 The deposition rate of the thin film layer was 0.1 nm / s.

[0117] S5. After the thin film deposition is completed, the vacuum chamber is cooled for 30 minutes to complete the preparation of the high temperature resistant filter.

[0118] Performance Testing

[0119] Figure 3 The spectral performance of the high temperature resistant filter prepared in Example 1 was detected by using the spectral detection instrument Cary7000 at room temperature (25°C). Figure 3 It can be seen that the transmittance of the high temperature resistant filter prepared by the present invention in the transmission band 425-465nm is above 95%, and the reflectance of the reflection band 420-425nm and 465-700nm is relatively low, both below 5%, thereby blocking the transmission of light in this band.

[0120] Figure 4 This is a real picture of a commercially available filter after a high-temperature test at 650°C.

[0121] Figure 5 This is a real picture of the high temperature resistant filter prepared in Example 1 after being subjected to a high temperature test at 650°C.

[0122] Figures 4-5 The testing method is to place the commercially available filter and the high temperature resistant filter prepared in Example 1 in a muffle furnace for heating treatment from 0°C to 650°C for 1 hour, then take out the sample, and then use tape to stick the film layer on the sample.

[0123] Depend on Figure 4 It can be seen that the film layer of the commercially available filter falls off after being tested at a high temperature of 650°C.

[0124] Depend on Figure 5 It can be seen that the high temperature resistant filter prepared in Example 1 is intact after the 650°C high temperature test, without cracks, deformation, falling off, etc., and can still maintain the precise optical screening capability of the filter.

[0125] Figure 6 The spectral performance of the high temperature resistant filter prepared in Example 1 was obtained by testing it with a spectral detection instrument Cary7000 after a 650°C high temperature test.

[0126] Depend on Figure 6 It can be seen that after the high temperature resistant filter prepared by the present invention has undergone a high temperature test at 650°C, the transmittance of the transmission band 425-465nm is still above 95%, and the reflectivity of the reflection bands 420-425nm and 465-700nm is still below 5%, and there is no obvious change before and after the 650°C high temperature test.

[0127] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high temperature resistant filter, characterized in that: include: substrate; A first high temperature resistant film layer, which is located on the surface of the substrate, and the first high temperature resistant film layer includes a plurality of first SiO2 film layers and first Al2O3 film layers which are sequentially staggered; A filter film layer, which is located on a surface of the first high temperature resistant film layer away from the substrate; The second high temperature resistant film layer is located on the surface of the filter film layer away from the substrate, and the second high temperature resistant film layer includes a plurality of second SiO2 film layers and second Al2O3 film layers which are sequentially staggered.

2. The high temperature resistant filter according to claim 1, characterized in that: The filter film layer includes a plurality of Ta2O5 thin film layers and a third SiO2 thin film layer which are alternately arranged in sequence.

3. The high temperature resistant filter according to any one of claims 1 to 2, characterized in that: The substrate is a sapphire substrate.

4. The high temperature resistant filter according to claim 2, characterized in that: The thickness of the first SiO2 thin film layer is 50 to 120 nm; The thickness of the first Al2O3 thin film layer is 20-30 nm; The thickness of the second SiO2 thin film layer is 50 to 120 nm; The thickness of the second Al2O3 thin film layer is 20-30 nm; The thickness of the Ta2O5 thin film layer is 10 to 120 nm; The thickness of the third SiO2 thin film layer is 10-150 nm.

5. The high temperature resistant filter according to claim 2, characterized in that: The number of interleavings of the first SiO2 thin film layer and the first Al2O3 thin film layer is 1 to 1000 times; The number of interleavings of the second SiO2 film layer and the second Al2O3 film layer is 1 to 1000 times; The number of interleavings of the Ta2O5 thin film layer and the third SiO2 thin film layer is 1 to 1000 times.

6. A method for preparing a high temperature resistant filter according to any one of claims 1 to 5, characterized in that: The following steps are involved: A first SiO2 thin film layer and a first Al2O3 thin film layer are sequentially and alternately deposited on the surface of the substrate to prepare a first high temperature resistant film layer; A filter film layer is prepared on the surface of the first high temperature resistant film layer; A second SiO2 thin film layer and a second Al2O3 thin film layer are sequentially and alternately deposited on the surface of the filter film layer to prepare a second high temperature resistant film layer.

7. The method for preparing a high temperature resistant filter according to claim 6, characterized in that: Using SiO2 particles and Al2O3 particles as evaporation sources, respectively, electron beam thermal evaporation method is used to alternately deposit the first SiO2 thin film layer and the first Al2O3 thin film layer on the substrate surface; When depositing the first SiO2 thin film layer and the first Al2O3 thin film layer, the substrate temperature is controlled to be 250-260°C, the deposition rate of the first SiO2 thin film layer is 0.2-0.3nm / s, and the deposition rate of the first Al2O3 thin film layer is 0.1-0.2nm / s.

8. The method for preparing a high temperature resistant filter according to claim 6, characterized in that: The filter film layer includes a plurality of Ta2O5 thin film layers and a third SiO2 thin film layer which are arranged alternately in sequence; The method of preparing a filter film layer on the surface of the first high temperature resistant film layer specifically includes the following steps: Ta2O5 particles and SiO2 particles are used as evaporation sources respectively, and an electron beam thermal evaporation method is used to alternately deposit a Ta2O5 thin film layer and a third SiO2 thin film layer on the surface of the first high-temperature resistant film layer, so as to prepare a filter film layer; When depositing the Ta2O5 thin film layer and the third SiO2 thin film layer, the substrate temperature is controlled to be 250-260°C, the deposition rate of the Ta2O5 thin film layer is 0.2-0.4nm / s, and the deposition rate of the third SiO2 thin film layer is 0.2-0.3nm / s.

9. The method for preparing a high temperature resistant filter according to claim 6, characterized in that: Using SiO2 particles and Al2O3 particles as evaporation sources respectively, electron beam thermal evaporation method is used to sequentially and alternately deposit the second SiO2 thin film layer and the second Al2O3 thin film layer on the surface of the filter film layer; When depositing the second SiO2 thin film layer and the second Al2O3 thin film layer, the substrate temperature is controlled to be 250-260°C, the deposition rate of the second SiO2 thin film layer is 0.2-0.3nm / s, and the deposition rate of the second Al2O3 thin film layer is 0.1-0.2nm / s.

10. The method for preparing a high temperature resistant filter according to any one of claims 6 to 9, characterized in that: Before the first SiO2 thin film layer and the first Al2O3 thin film layer are alternately deposited on the surface of the substrate in sequence, the substrate is also subjected to plasma treatment, wherein the plasma treatment gas includes oxygen and argon, the oxygen flow rate is 50-60sccm, the argon flow rate is 8-10sccm, the plasma treatment time is 60-120s, the voltage is 700-710V, and the current is 700-710mA.

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