Dichroscope optical film and plating method thereof

Abstract

The invention provides a dichroscope optical thin film and a plating method thereof, the dichroscope optical thin film is made of three thin film materials, SiO2 with excellent laser resistance is selected as a low-refractive-index material, and Ta2O5 with very high refractive index and metal Hf with low deep ultraviolet absorption are selected as a high-refractive-index material. A Ta2O5-SiO2 film stack is adopted on the inner side of the whole film layer structure, namely the part with small reflection and absorption, and the requirement for high reflectivity is met through a small number of film layers by utilizing the advantage of large refractive index ratio of the Ta2O5-SiO2 film stack; the Hf-SiO2 membrane stack is superposed on the outermost part of the Ta2O5-SiO2 membrane stack, so that the reflectivity of a deep ultraviolet band can reach the standard, and a half-wave protection effect for improving the laser damage capability of Ta2O5-SiO2 is also achieved.

Description

Technical Field

[0001] The invention relates to the field of optical technology, and in particular to a dichroic mirror optical film and a coating method thereof. Background Art

[0002] Dichroic mirrors are a special type of optical element that can selectively transmit certain wavelengths of light and reflect other wavelengths of light. This characteristic makes dichroic mirrors widely used in a variety of optical systems. In order to simultaneously meet the requirements of high reflectivity of dichroic mirrors in deep ultraviolet and high transmittance in near infrared, the following principles must be met when designing high-performance beam splitting films, i.e., dichroic mirror optical films: First, select a combination of materials with a large difference in high and low refractive indices to reduce the number of coating layers, reduce the difficulty of preparation and production costs; second, from the perspective of the spectral curve of the film, the film material should have extremely low absorption performance in deep ultraviolet to ensure its reflectivity.

[0003] Considering the possible refractive index difference between high and low refractive index materials and the absorption problem of deep ultraviolet light, the high refractive index materials available are very limited, such as tantalum pentoxide (Ta 2 O 5 ), titanium dioxide (TiO 2 ), niobium pentoxide (Nb 2 O 5 ) are generally low melting point materials, and their absorption rate in deep ultraviolet is relatively large. During laser irradiation, the energy accumulation has a significant ablation effect on the film. Deep ultraviolet has high refractive index materials with low absorption rate, such as hafnium dioxide (HfO 2 ), aluminum oxide (Al 2 O 3 ), calcium fluoride (CaF 2 ), etc., whose refractive index is often low, and to achieve high reflectivity, there are disadvantages such as many layers required, rough film surface, great difficulty in plating, easy film stripping and high cost. Therefore, an effective solution is urgently needed to solve the above problems. Summary of the invention

[0004] The present invention provides a dichroic optical film and a coating method thereof, which are used to solve the defects of the prior art such as large number of layers required, rough film surface, great coating difficulty, easy film stripping and high cost, and achieve the requirements of high reflectivity and high damage threshold by using fewer film layers.

[0005] The invention provides a dichroic mirror optical film, which consists of a tantalum pentoxide film layer, a silicon dioxide film layer and a metal hafnium film layer plated on the dichroic mirror.

[0006] According to a dichroic mirror optical film provided by the present invention, the dichroic mirror comprises a first coating surface and a second coating surface; The dichroic optical film comprises a beam splitting film coated on the first coating surface and an anti-reflection film coated on the second coating surface; The beam splitting film is composed of the tantalum pentoxide film layer, the silicon dioxide film layer and the metal hafnium film layer; The antireflection film is composed of the silicon dioxide film layer and the metal hafnium film layer.

[0007] According to a dichroic optical film provided by the present invention, the beam splitting film is composed of a long-wave pass film system and a high-reflection film; The long-wave pass film is composed of the tantalum pentoxide film layer and the silicon dioxide film layer; The high reflective film is composed of the silicon dioxide film layer and the metal hafnium film layer.

[0008] According to a dichroic optical film provided by the present invention, the beam splitting films are sequentially composed of at least one layer of the long-wave pass film system and at least one layer of the high-reflection film in order from near to far from the first coating surface; The antireflection film comprises at least one silicon dioxide film layer and at least one metal hafnium film layer sequentially cross-plated on the second coating surface; the first film layer of the antireflection film plated on the second coating surface is a silicon dioxide film layer.

[0009] The present invention also provides a method for coating the above-mentioned dichroic mirror optical film, comprising: Use the Hall ion source to etch the base film layer of the dichroic mirror for 10-15 minutes, and keep the background vacuum degree below 2*10 -3 Pascal, deposition temperature is 150-200 degrees Celsius, constant temperature for 10-20 minutes; A dichroic mirror optical thin film consisting of a tantalum pentoxide film layer, a silicon dioxide film layer and a metal hafnium film layer is plated on the surface of the dichroic mirror.

[0010] According to a coating method of a dichroic mirror optical film provided by the present invention, the dichroic mirror comprises a first coating surface and a second coating surface, the dichroic mirror optical film comprises a beam splitting film coated on the first coating surface and an anti-reflection film coated on the second coating surface, and the beam splitting film is composed of a long-wave pass film system and a high-reflection film; The method of coating a dichroic mirror optical film composed of a tantalum pentoxide film layer, a silicon dioxide film layer and a metal hafnium film layer on the surface of the dichroic mirror comprises: Sequentially coating the long-wave pass film system and the high-reflection film on the first coating surface; The antireflection film is plated on the second plated surface.

[0011] According to a coating method of a dichroic optical film provided by the present invention, the long-wave pass film is composed of the tantalum pentoxide film layer and the silicon dioxide film layer, and the high-reflection film is composed of the silicon dioxide film layer and the metal hafnium film layer; The step of sequentially coating the long-wave pass film system and the high-reflection film on the first coating surface comprises: When the tantalum pentoxide film layer in the long-wave pass film system is plated, an ion source is used for auxiliary evaporation, and the deposition rate is controlled to be 0.2-0.3 nanometers per second, and the oxygen filling amount is 10-20 standard cubic centimeters per minute; when the silicon dioxide film layer in the long-wave pass film system is plated, an ion source is used for auxiliary evaporation, and the deposition rate is controlled to be 0.5-0.6 nanometers per second; After the long-wave pass film system is plated, the plating is suspended for 10-20 minutes and then the high-reflection film is plated; When the metal hafnium film layer in the high-reflective film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.06-0.08 nanometers per second, and the oxygen filling amount is 60-80 standard cubic centimeters per minute; when the silicon dioxide film layer in the high-reflective film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.5-0.6 nanometers per second.

[0012] According to a method for coating a dichroic optical film provided by the present invention, the antireflection film is composed of the silicon dioxide film layer and the metal hafnium film layer; The step of coating the antireflection film on the second coating surface comprises: Coating a first silicon dioxide film layer of the antireflection film on the second coating surface; After the first silicon dioxide film layer is deposited, the deposition is suspended for 10-20 minutes before depositing the metal hafnium film layer and other silicon dioxide film layers of the anti-reflection film, wherein the other silicon dioxide film layers are any silicon dioxide film layers in the anti-reflection film except the first silicon dioxide film layer; When the metal hafnium film layer in the antireflection film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.06-0.08 nanometers per second, and the oxygen filling amount is 60-80 standard cubic centimeters per minute; When the silicon dioxide film layer in the antireflection film is plated, the deposition rate is controlled to be 0.5-0.6 nanometers per second, and an ion source is used to assist in evaporation deposition of the first silicon dioxide film layer, and an electron gun is used to assist in evaporation deposition of the other silicon dioxide film layers.

[0013] According to a method for coating a dichroic optical film provided by the present invention, before sequentially coating the long-wave pass film system and the high-reflection film on the first coating surface, the method further comprises: Obtaining a plating ratio parameter and a plating target corresponding to the dichroic mirror; According to the plating target and the plating ratio parameter, respectively determining the target plating thickness of each tantalum pentoxide film layer, the target plating thickness of each silicon dioxide film layer, and the target plating thickness of each metal hafnium film layer in the beam splitting film; According to the target coating thickness of each silicon dioxide film layer in the long-wave pass film system, the coating target and the coating ratio parameter, the target coating thickness of each silicon dioxide film layer and the target coating thickness of each metal hafnium film layer in the anti-reflection film are determined respectively.

[0014] According to a coating method for a dichroic mirror optical film provided by the present invention, the target coating thickness of each silicon dioxide film layer and the target coating thickness of each metal hafnium film layer in the antireflection film are determined according to the target coating thickness of each silicon dioxide film layer in the long-wave pass film system, the coating target and the coating ratio parameter, respectively, comprising: Calculating the sum of the target coating thicknesses of the silicon dioxide film layers in the long-wave pass film system to obtain the target coating thickness of the first silicon dioxide film layer in the anti-reflection film; According to the target coating thickness of the first silicon dioxide film layer, the coating target and the coating ratio parameter, the target coating thickness of each other silicon dioxide film layer in the anti-reflection film and the target coating thickness of each metal hafnium film layer are determined respectively, and the other silicon dioxide film layer is any silicon dioxide film layer in the anti-reflection film except the first silicon dioxide film layer.

[0015] The dichroic optical film and the coating method thereof provided by the present invention use three kinds of film materials instead, and the low refractive index material is SiO2 with excellent anti-laser performance. 2 , high refractive index material uses Ta with a very high refractive index 2 O 5 And deep ultraviolet low absorption metal Hf. Ta is used on the inner side of the entire film structure, that is, the part with less reflection and absorption 2 O 5 -SiO 2 Film stack, taking advantage of its large refractive index ratio, can achieve high reflectivity requirements with fewer film layers; in Ta 2 O 5 -SiO 2 The outermost part of the membrane stack is stacked with Hf-SiO 2 The film stack ensures that the reflectivity in the deep ultraviolet band meets the standard. 2 The film stack combination has strong resistance to laser damage to ensure the laser resistance of the entire film layer. 2 O 5 -SiO 2It plays a half-wave protection role in improving its laser damage resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic flow chart of the coating method of the dichroic mirror optical film provided by the present invention.

[0018] Figure 2 It is a schematic diagram of the dimensions of the dichroic mirror provided by the present invention.

[0019] Figure 3 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 29°.

[0020] Figure 4 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 61°.

[0021] Figure 5 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 29°.

[0022] Figure 6 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 50°.

[0023] Figure 7 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 61°.

[0024] Figure 8 It is a spectrum curve diagram of the residual reflectivity and transmittance of the dichroic mirror provided by the present invention at an incident angle of 29-61°.

[0025] Fig. 9 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 29-61°. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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.

[0027] Combine the following Figure 1-Figure 9 The dichroic optical film and the coating method thereof of the present invention are described.

[0028] In order to facilitate a clearer understanding of the technical solutions of the embodiments of the present application, some technical contents related to the embodiments of the present application are first introduced.

[0029] Hafnium is a metallic element with the symbol Hf, atomic number 72 and atomic weight 178.49.

[0030] Silicon dioxide is an inorganic compound with the chemical formula SiO 2 Silicon dioxide has a very small absorption coefficient at the working wavelength, uniform particle growth, an amorphous film structure, and a high laser damage threshold, making it an ideal low-refractive index material.

[0031] Tantalum pentoxide is a white, colorless crystalline powder. It is the most common oxide of tantalum and the final product of tantalum combustion in air. Its chemical formula is Ta 2 O 5 .

[0032] Vacuum evaporation: referred to as evaporation, refers to a process in which a certain heating evaporation method is used to evaporate the coating material (or film material) under vacuum conditions and gasify it, so that the particles fly to the surface of the substrate and condense into a film. Evaporation is an earlier and more widely used vapor deposition technology, with the advantages of simple film formation method, high film purity and density, and unique film structure and performance.

[0033] Coating fixture: It plays the role of supporting optical components during the vacuum evaporation process of optical components, such as planetary fixtures. Unlike optical components, coating fixtures are usually made of metal materials, such as aluminum alloy, stainless steel, etc.

[0034] The working principle of the dichroic mirror is based on the thin film interference effect. By depositing multiple layers of thin films with different refractive indices on glass or other transparent substrates, a complex optical interference system is formed. When light is incident on such a multi-layer film structure, light of different wavelengths will be partially or completely reflected due to interference, while light of other wavelengths will pass through the lens.

[0035] With the development of science and technology, especially driven by the needs of laser technology, optical communications, biomedicine and other fields, the research and application of dichroic mirrors have developed rapidly. For example, in laser technology, dichroic mirrors can be used for output coupling of lasers; in optical communications, dichroic mirrors can be used for separation of optical signals. In addition, the Thin Film Optics Laboratory of the Shanghai Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, proposed a new design method for dichroic mirrors based on mixed film layers and sandwich-like structure interfaces. This new design method realizes the preparation of dichroic mirrors with excellent spectral performance and high laser damage threshold at two wavelengths.

[0036] Dichroic mirrors are widely used in many fields: Biomedical field: In fluorescence microscope systems, dichroic mirrors are used to separate excitation light and fluorescence signals to improve the clarity and contrast of fluorescence images.

[0037] Spectral analysis: Dichroic mirrors are used as beam splitting elements in spectrometers to separate light sources into different spectral components for spectral analysis.

[0038] Stage lighting: In stage lighting systems, dichroic mirrors are used to achieve color separation, mixing and adjustment to enhance the visual effects of stage lighting.

[0039] Laser technology: Dichroic mirrors are used as components in lasers to select a specific wavelength for the laser output.

[0040] Optical filtering: In optical communications and spectroscopy, dichroic mirrors are used to filter out or select specific wavelengths of light signals.

[0041] High-power laser beam combining: The dichroic mirror beam combining technology can relax the line width requirement of sub-beam lasers to several nanometers, requiring fewer optical components, convenient optical path arrangement, compact structure, and easy integration. With the development of coating technology, the power handling capacity and steepness of dichroic mirrors have been greatly improved, which can meet the needs of laser beam combining from several kilowatts to tens of kilowatts.

[0042] An embodiment of the present invention provides a dichroic mirror optical film, wherein the dichroic mirror optical film is formed by coating Ta on a dichroic mirror. 2 O 5 Film layer, S i O 2 film layer and metal Hf film layer.

[0043] Among them, the dichroic optical film is mainly a dichroic film required by the large-angle film system in the ultraviolet-visible-near infrared band. The dichroic optical film adopts G|Ta 2 O 5 -SiO 2 -Hf-SiO 2|A multi-material film structure, where G is the substrate and A is air.

[0044] Specifically, the dichroic optical film includes at least one layer of Ta 2 O 5 Film layer, at least one layer of S i O 2 film layer and at least one metal Hf film layer.

[0045] The dichroic optical film provided by the embodiment of the present invention does not use the traditional two kinds of high and low refractive index film materials, but uses three kinds of film materials instead. The low refractive index material is SiO2 with excellent anti-laser performance. 2 (refractive index n=1.465), high refractive index material uses Ta with a very high refractive index 2 O 5 (n=2.2) and deep ultraviolet low absorption metal Hf (n=1.9). Ta is used on the inner side of the entire film structure, that is, the part with less reflection and absorption. 2 O 5 -SiO 2 Film stack, taking advantage of its large refractive index ratio, can achieve high reflectivity requirements with fewer film layers; in Ta 2 O 5 -SiO 2 The outermost part of the membrane stack is stacked with Hf-SiO 2 The film stack ensures that the reflectivity in the deep ultraviolet band meets the standard. 2 The film stack combination has strong resistance to laser damage to ensure the laser resistance of the entire film layer. 2 O 5 -SiO 2 It plays a half-wave protection role in improving its laser damage resistance, and using fewer film layers can meet the requirements of high reflectivity and high damage threshold.

[0046] In one or more optional embodiments of the present invention, the dichroic mirror comprises a first coating surface and a second coating surface; the dichroic mirror optical film comprises a beam splitter film coated on the first coating surface and an anti-reflection film coated on the second coating surface; the beam splitter film is composed of the Ta 2 O 5 The SiO 2 film layer and the metal Hf film layer; the antireflection film is composed of the SiO 2 The film layer and the metal Hf film layer.

[0047] Specifically, the dichroic mirror includes two coated surfaces: a first coated surface and a second coated surface, and the dichroic mirror may be a plane mirror.

[0048] In practical applications, the optical film of the dichroic mirror includes a beam splitter film and an anti-reflection film, and the beam splitter film and the anti-reflection film are respectively coated on the two coating surfaces of the dichroic mirror, that is, the beam splitter film is coated on one coating surface, and the anti-reflection film is coated on the other coating surface.

[0049] Among them, the beam splitting film is composed of at least one layer of Ta 2 O 5 Film layer, at least one layer of SiO 2 film layer and at least one metal Hf film layer; the antireflection film is composed of at least one SiO 2 The film layer and at least one metal Hf film layer are alternately stacked.

[0050] The dichroic optical film provided by the embodiment of the present invention adopts an anti-reflection agent with less reflection absorption and utilizes the advantage of its large refractive index ratio to achieve the requirement of high reflectivity with a fewer number of film layers; it can further enable the dichroic optical film to have strong resistance to laser damage to ensure the laser resistance of the entire film layer, play a half-wave protection role in improving the laser damage resistance, and use a fewer number of film layers to meet the requirements of high reflectivity and high damage threshold.

[0051] In one or more optional embodiments of the present invention, the beam splitting film is composed of a long-wave pass film system and a high-reflection film; the long-wave pass film system is composed of the Ta 2 O 5 The SiO film layer 2 The high reflective film is composed of the SiO 2 The film layer and the metal Hf film layer.

[0052] In practical applications, due to Ta 2 O 5 The transmission range is basically between 330 and 10000 nm, so the membrane material Ta is used. 2 O 5 With SiO 2 The characteristics of the long-wavelength film system greater than 330nm (usually 330nm-1500nm) are made, and then the film material metal Hf and SiO 2 The characteristics of the high-reflective film of 250nm~330nm can be made. In this way, the dichroic optical film can be guaranteed to meet the requirements of high reflectivity and high damage threshold with fewer film layers.

[0053] In one or more optional embodiments of the present invention, the beam splitting film is sequentially composed of at least one layer of the long-wave pass film system and at least one layer of the high-reflection film in order from near to far from the first coating surface; the anti-reflection film comprises at least one SiO2 layer sequentially cross-coated on the second coating surface. 2 film layer and at least one of the metal Hf film layers; the first film layer of the antireflection film coated on the second coating surface is SiO2 Membrane layer.

[0054] Specifically, the beam splitter film adopts a G|0.88(0.5LM 0.5L)^16 0.79(HL)^12 0.67(HL)^110.58(HL)^11 0.49(HL)^11|A structure with a central wavelength of 550 nanometers (nm), where M is a high refractive index material Ta. 2 O 5 , H is a high refractive index material metal Hf, L is a low refractive index material SiO 2 , (0.5LM 0.5L)^S is a classic long-wave film system (Ta 2 O 5 -SiO 2 Film stack), (HL)^S is a classic high reflection film (Hf-SiO 2 film stack), 0.88 is the scale factor of the long-wave pass film system, 16 is the number of stacked layers of the long-wave pass film system, and 0.5 is the SiO 2 The scaling factors of the film layers are 0.79, 0.67, 0.58 and 0.49, which are the scaling factors of each high-reflection film respectively, and 12, 11, 11 and 11 are the stacking layers of each high-reflection film respectively.

[0055] The dichroic optical film provided by the embodiment of the present invention does not use the traditional two kinds of high and low refractive index film materials, but uses three kinds of film materials instead. The low refractive index material is SiO2 with excellent anti-laser performance. 2 (refractive index n=1.465), high refractive index material uses Ta with a very high refractive index 2 O 5 (n=2.2) and deep ultraviolet low absorption metal Hf (n=1.9). Using G|Ta 2 O 5 -SiO 2 -Hf-SiO 2 |A film structure, the inner side of the entire film structure, that is, the part with less reflection and absorption, uses Ta 2 O 5 -SiO 2 Film stack, taking advantage of its large refractive index ratio, can achieve high reflectivity requirements with fewer film layers; in Ta 2 O 5 -SiO 2 The outermost part of the membrane stack is stacked with Hf-SiO 2 The film stack ensures that the reflectivity in the deep ultraviolet band meets the standard. 2 The film stack combination has strong resistance to laser damage to ensure the laser resistance of the entire film layer. 2 O 5 -SiO2 It plays a half-wave protection role in improving its laser damage resistance, and using fewer film layers can meet the requirements of high reflectivity and high damage threshold.

[0056] Figure 1 is a schematic flow chart of a method for coating a dichroic optical film provided by the present invention, such as Figure 1 As shown, the method includes step 101 and step 102.

[0057] Step 101: Use the Hall ion source to etch the base film layer of the dichroic mirror for 10-15 minutes (min), and keep the background vacuum degree below 2*10 -3 Pascal (Pa), deposition temperature is 150-200 degrees Celsius (℃), constant temperature for 10-20min.

[0058] In practical applications, in order to ensure the success rate of dichroic mirror optical thin film coating, the dichroic mirror needs to be pre-treated before coating. That is, before coating the dichroic mirror optical thin film, the previous base film layer needs to be etched with a Hall ion source for 10-15 minutes, and the background vacuum degree should be kept below 2*10 -3 Pa, deposition temperature is 150-200℃, constant temperature for 10-20min.

[0059] Step 102: Coating the surface of the dichroic mirror with Ta 2 O 5 Film, SiO 2 A dichroic optical film composed of a film layer and a metal Hf film layer.

[0060] After pre-treatment of the dichroic mirror, the dichroic mirror can be fixed with a coating fixture, and then Ta is coated on the surface of the dichroic mirror. 2 O 5 Film, SiO 2 Film layer and metal Hf film layer, that is, dichroic mirror optical film.

[0061] Among them, the dichroic mirror optical film can be plated by ion source assisted deposition electron beam evaporation method or vacuum evaporation method.

[0062] In one or more optional embodiments of the present invention, the dichroic mirror comprises a first coating surface and a second coating surface, the dichroic mirror optical film comprises a beam splitter film coated on the first coating surface and an anti-reflection film coated on the second coating surface, the beam splitter film is composed of a long-wave pass film system and a high-reflection film; accordingly, the surface of the dichroic mirror is coated with Ta 2 O 5 Film, SiO 2 The dichroic optical film composed of a film layer and a metal Hf film layer includes: Sequentially coating the long-wave pass film system and the high-reflection film on the first coating surface; The antireflection film is plated on the second plated surface.

[0063] In practical applications, a long-wave pass film system and a high-reflection film can be coated on the first coating surface of the dichroic mirror, and an anti-reflection film can be coated on the second coating surface to ensure the integrity and accuracy of the optical characteristics of the dichroic mirror optical film.

[0064] In one or more optional embodiments of the present invention, the long-wave pass film is composed of the Ta 2 O 5 The SiO film layer 2 The high reflective film is composed of the SiO 2 film layer and the metal Hf film layer; accordingly, the long-wave pass film system and the high-reflection film are sequentially plated on the first plated surface, comprising: Plating the Ta in the long wave pass film system 2 O 5 When coating the film, an ion source is used for auxiliary evaporation, and the deposition rate is controlled to be 0.2-0.3 nanometers per second (nm / s), and the oxygen filling amount is 10-20 standard cubic centimeters per minute (SCCM); the SiO 2 When forming the film layer, an ion source is used for auxiliary evaporation, and the deposition rate is controlled to be 0.5-0.6nm / s; After the long-wave pass film system is plated, the plating is suspended for 10-20 minutes and then the high-reflective film is plated; When the metal Hf film layer in the high-reflection film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.06-0.08 nm / s, and the oxygen filling amount is 60-80 SCCM; when the SiO 2 When forming the film layer, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.5-0.6 nm / s.

[0065] In Ta 2 O 5 -SiO 2 In the combination (long wave pass film system), Ta 2 O 5 With SiO 2 Ion sources are used for auxiliary evaporation to ensure the firmness of the film layer. 2 O 5 When depositing the film layer, the deposition rate is controlled to be 0.2-0.3nm / s, the oxygen filling amount is 10-20SCCM, and the film is formed by ion source assisted evaporation. 2When forming the film layer, the deposition rate is controlled to be 0.5-0.6 nm / s, and the film is formed by ion source assisted evaporation.

[0066] In Ta 2 O 5 -SiO 2 After the combination plating is completed, on the SiO 2 Set a pause plating time of 10-20 minutes at the junction of the Hf film layer (the last film layer of the long-wave pass film system is SiO 2 The first film layer of the high-reflective film is a metal Hf film layer) to ensure the firmness of the base film layer during Hf evaporation. 2 In the combination (high reflection film), when coating each metal Hf film layer, the deposition rate is controlled to be 0.06-0.08nm / s, the oxygen filling amount is 60-80SCCM, and the film is formed by electron gun evaporation. 2 When forming the film layer, the deposition rate is controlled to be 0.5-0.6nm / s, and the film is formed by electron gun evaporation. In this stage, no ion source is used for auxiliary evaporation to prevent absorption in the deep ultraviolet band and thus affect the spectral curve.

[0067] In addition, since the high reflective film is Hf-SiO 2 Combination, in SiO 2 A plating pause of 10-20 minutes is also required at the junction with the Hf film layer.

[0068] In one or more optional embodiments of the present invention, the antireflection film is made of the SiO 2 film layer and the metal Hf film layer; accordingly, coating the antireflection film on the second coating surface comprises: The first SiO layer of the antireflection film is coated on the second coating surface. 2 Membrane layer; In the first layer of SiO 2 After the film coating is completed, the coating is suspended for 10-20 minutes before the metal Hf film and other SiO 2 film layer, the other SiO 2 The film layer is the antireflection film except the first layer of SiO 2 Any SiO outside the film 2 Membrane layer; When the metal Hf film layer in the antireflection film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.06-0.08 nm / s, and the oxygen filling amount is 60-80 SCCM; The SiO in the antireflection film is coated 2 When depositing the first SiO layer, the deposition rate was controlled to be 0.5-0.6 SCCM, and an ion source was used to deposit the first SiO2 The film layer is assisted by evaporation, and the other SiO 2 The film layer is subjected to auxiliary evaporation.

[0069] Due to the large diameter-to-thickness ratio of the dichroic mirror, the first coating surface will have a significant impact on the surface shape of the original after the beam splitter coating is applied. In order to minimize the impact of the first coating surface after the beam splitter coating is applied, the first coating surface produces a film layer with greater stress when using the Ta in the ion source. 2 O 5 -SiO 2 combination (long wave pass film system), so the first layer (SiO 2 When the first layer is completed, the SiO 2 A pause of 10-20 minutes is set at the junction of the Hf film layer to ensure the firmness of the base film layer during Hf evaporation. 2 In the combination, when coating each metal HF film layer, the deposition rate is controlled to be 0.06-0.08nm / s, the oxygen filling amount is 60-80SCCM, and the film is formed by electron gun evaporation. 2 When forming the film layer, the deposition rate is controlled to be 0.5-0.6nm / s, and the film is formed by electron gun evaporation.

[0070] In one or more optional embodiments of the present invention, before sequentially coating the long-wave pass film system and the high-reflection film on the first coating surface, the method further includes: Obtaining a plating ratio parameter and a plating target corresponding to the dichroic mirror; According to the coating target and the coating ratio parameter, the Ta of each of the beam splitting films is determined respectively. 2 O 5 The target coating thickness of the film layer, the SiO 2 The target plating thickness of the film layer and the target plating thickness of each of the metal Hf film layers; According to the SiO 2 The target coating thickness of the film layer, the coating target and the coating ratio parameters are used to determine the SiO 2 The target plating thickness of the film layer and the target plating thickness of each of the metal Hf film layers.

[0071] Specifically, the plating ratio parameter and the plating target corresponding to the dichroic mirror can be obtained first, where Ta 2 O 5 、SiO 2Hf and Hf may share a plating ratio parameter, or may correspond to their own plating ratio parameters. The plating ratio parameter may be pre-set, or may be calculated according to actual conditions. The present invention does not limit this.

[0072] Then, simulation and analysis were performed based on the coating target to obtain the Ta content of each component in the spectroscopic film. 2 O 5 The simulated coating thickness of the film layer, each SiO 2 The simulated coating thickness of the film layer and the simulated coating thickness of each metal Hf film layer. 2 O 5 The simulated coating thickness of the film layer is multiplied by the corresponding coating ratio parameter to obtain the Ta 2 O 5 The target coating thickness of the film layer; 2 The simulated coating thickness of the film layer is multiplied by the corresponding coating ratio parameter to obtain the SiO 2 The target coating thickness of the film layer; the simulated coating thickness of each metal Hf film layer in the spectroscopic film is multiplied by the corresponding coating ratio parameter to obtain the target coating thickness of each metal Hf film layer in the spectroscopic film.

[0073] Furthermore, according to all SiO 2 The target coating thickness, coating target and coating ratio parameters of the film layer are simulated, analyzed and calculated to obtain the SiO 2 The target coating thickness of the film layer and the target coating thickness of each metal Hf film layer. 2 O 5 The target coating thickness of the film layer, each SiO 2 The target coating thickness of the film layer and the target coating thickness of each metal Hf film layer are coated on the first coating surface in sequence. 2 The target coating thickness of the film layer and the target coating thickness of each metal Hf film layer are determined, and an anti-reflection film is coated on the second coating surface.

[0074] It should be noted that the plating ratio parameters include Ta 2 O 5 Plating ratio parameters, SiO 2 The plating ratio parameters of Hf and Hf are obtained; accordingly, the process of obtaining the plating ratio parameters can be as follows: Obtain a first lens, a second lens, and a third lens made of the same base material as the dichroic mirror; The surface of the first lens is coated with Ta of a first set thickness. 2 O 5A SiO film layer of a second set thickness is plated on the surface of the second lens. 2 A film layer, wherein a metal Hf film layer having a third set thickness is plated on the surface of the third lens; The Ta on the second lens is determined by simulation analysis based on the plated second lens. 2 O 5 The simulated coating thickness of the film layer is determined by performing simulation analysis on the second lens after coating to determine the SiO 2 The simulated coating thickness of the film layer is determined by performing a simulation analysis on the third lens after coating to determine the simulated coating thickness of the metal Hf film layer on the third lens; The first set thickness and Ta on the first lens 2 O 5 The ratio of the simulated plating thickness of the film layer is determined as the Ta 2 O 5 The coating ratio parameter corresponding to the film layer is to combine the second set thickness with the SiO 2 The ratio of the simulated coating thickness of the film layer is determined as the SiO 2 The coating ratio parameter corresponding to the film layer is determined by determining the ratio of the third set thickness to the simulated coating thickness of the metal Hf film layer on the third lens as the coating ratio parameter corresponding to the metal Hf film layer.

[0075] Specifically, the first lens, the second lens and the third lens can be three identical plane mirrors. The first set thickness, the second set thickness and the third set thickness can be the same or different, wherein the first set thickness is Ta on the first lens. 2 O 5 The actual coating thickness of the film layer, the second set thickness is the SiO 2 The actual coating thickness of the film layer, the third set thickness is the actual coating thickness of the metal Hf film layer on the third lens. The first set thickness, the second set thickness and the third set thickness are 150-300 nanometers.

[0076] In one or more optional embodiments of the present invention, the SiO 2 The target coating thickness of the film layer, the coating target and the coating ratio parameters are used to determine the SiO 2 The target plating thickness of the film layer and the target plating thickness of each of the metal Hf film layers include: Calculate the SiO 2 The target coating thickness of the film layer is the sum of the first SiO 2 Target coating thickness of the film layer; According to the first SiO 2 The target coating thickness of the film layer, the coating target and the coating ratio parameter respectively determine the other SiO 2 The target plating thickness of the film layer and the target plating thickness of each of the metal Hf film layers, the other SiO 2 The film layer is any SiO2 film layer other than the first silicon dioxide film layer in the antireflection film. 2 Membrane layer.

[0077] In practical applications, the first layer of the antireflection film (the first layer of SiO 2 The thickness of the film layer is Ta 2 O 5 With SiO 2 All SiO in the combination (long wave pass film system) 2 The sum of the target coating thickness of the film layers.

[0078] Then, the first layer of SiO 2 The ratio of the target coating thickness of the film layer to the coating ratio parameter is used as the first layer of SiO 2 The simulated coating thickness of the film layer is based on the first layer of SiO 2 The simulated coating thickness of the film layer and the coating target are simulated to obtain the other SiO 2 The simulated plating thickness of the film layer and the simulated plating thickness of each of the metal Hf film layers.

[0079] Furthermore, the other SiO 2 The simulated coating thickness of the film layer is multiplied by the corresponding coating ratio parameter to obtain the other SiO 2 The target coating thickness of the film layer; the simulated coating thickness of each metal Hf film layer in the anti-reflection film is multiplied by the corresponding coating ratio parameter to obtain the target coating thickness of each metal Hf film layer in the anti-reflection film.

[0080] The coating method of the dichroic mirror optical film provided by the present invention is further described below with reference to specific examples.

[0081] First obtain the dichroic mirror to be coated, see Figure 2 , Figure 2 Schematic diagram of the dimensions of the dichroic mirror provided by the present invention. Figure 2 From the front and rear views of the dichroic mirror, it can be seen that the lower half length and upper half length of the dichroic mirror are , the left half width is , the right half width is ; length is , thickness is 14.091mm ±0.0150 , the center thickness is 14.142mm.

[0082] The above-mentioned dichroic mirror is coated with a spectroscopic film on the S1 surface, and its film system indicators are as follows: average reflectivity Ravg>96%@250-460nm, 29-61 degrees (deg); average transmittance Tavg>90%@1050-1100nm, 1200-1400nm, 29-61deg; and an anti-reflection film is coated on the S2 surface, and its film system indicators are: Ravg<5%@250-650nm, 1050-1100nm, 1200-1400nm, 29-50deg; Ravg<10% @250-650nm, 1050-1100nm, 1200-1400nm, 50-61deg. As can be seen from the above, S1 requires an average residual reflectivity of 96% under the requirements of deep ultraviolet and large angles, and an average transmittance of 90% under the requirements of near infrared and large angles; S2 requires a certain residual reflectivity under the requirements of deep ultraviolet, near infrared and large angles.

[0083] The S1 surface is coated with a spectroscopic film, including film system design and process preparation.

[0084] Film system design: According to the film system indicators, a G| Ta 2 O 5 -SiO 2 -Hf-SiO 2 |A multi-material film structure, the specific film structure is G|0.88(0.5LM 0.5L)^16 0.79(HL)^12 0.67(HL)^11 0.58(HL)^110.49(HL)^11|A, the central wavelength is 550 nanometers (nm), where M is the high refractive index material Ta 2 O 5 , H is a high refractive index material metal Hf, L is a low refractive index material SiO 2 , (0.5LM 0.5L)^S is a classic long-wave film system (Ta 2 O 5 -SiO 2 Film stack), (HL)^S is a classic high reflection film (Hf-SiO 2 membrane stack). 2 O 5 The transmission range is basically between 330 and 10000 nm, so the membrane material Ta is used. 2 O 5 With SiO 2 The characteristics of the long-wavelength film system greater than 330nm (usually 330nm-1500nm) are made, and then the film material metal Hf and SiO 2The characteristics of the high-reflective film of 250nm~330nm can be made. In this way, the dichroic optical film can be guaranteed to meet the requirements of high reflectivity and high damage threshold with fewer film layers.

[0085] Then the membrane system designed by the original membrane stack cannot directly meet the requirements of the drawing, so after using the software to give the target for optimization, such as Figure 3 and Figure 4 shown. Figure 3 is a spectrum curve of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 29°, Figure 4 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 61°. Figure 3 and Figure 4 In the above example, the parameters are different except for the incident angle ( Figure 3 The incident angle is 29°. Figure 4 The incident angle is 61°), and other parameters are the same. Light source: white light; Incident medium: air; Substrate refractive index: 1.46; Exit refractive index: 1.46; Detection: ideal state; Central wavelength: 550nm; First surface: front surface; There are three polarization states: average, S (Senkrecht, vertically polarized light) and P (Parallel, parallel polarized light).

[0086] The software can calculate that the design value at 29° is Ravg=99.3%@250-460nm, 29deg; Tavg=98.7%@1050-1100nm, 29deg; Tavg=99.7%@1200-1400nm, 29deg; the design value at 61° is Ravg=97.7%@250-460nm, 61deg; Tavg=96.7% @1050-1100nm, 61deg; Tavg=96.3%@1200-1400nm, 61deg; all the above indicators can meet the requirements.

[0087] Process preparation: According to the film system index, this embodiment uses a new process plating method: 2 O 5 -SiO 2 In the combination, the previous base film layer needs to be etched with a Hall ion source for 10-15 minutes, and the background vacuum degree should be kept below 2*10 -3 Pa, deposition temperature is 150-200℃, constant temperature for 10-20 minutes; Ta 2 O 5 With SiO 2 Ion sources are used for auxiliary evaporation to ensure the firmness of the film layer. 2 O 5When depositing the film layer, the deposition rate is controlled to be 0.2-0.3nm / s, the oxygen filling amount is 10-20SCCM, and the film is formed by ion source assisted evaporation. 2 When forming the film layer, the deposition rate is controlled to be 0.5-0.6 nm / s, and the film is formed by ion source assisted evaporation.

[0088] See Table 1, which shows the plating ratio parameters (Tooling) under the process conditions.

[0089] Table 1 330~1400nm band film material plating ratio parameters

[0090] In the above 2 O 5 -SiO 2 After the combination plating is completed, on the SiO 2 A pause of 10-20 minutes is set at the junction of the Hf film layer to ensure the firmness of the base film layer during Hf evaporation. 2 In the combination, when coating each metal Hf film layer, the deposition rate is controlled to be 0.06-0.08nm / s, the oxygen filling amount is 60-80SCCM, and the film is formed by electron gun evaporation. 2 When forming the film layer, the deposition rate is controlled to be 0.5-0.6nm / s, and the film is formed by electron gun evaporation. (In this stage, no ion source is used for auxiliary evaporation to prevent absorption in the deep ultraviolet band and thus affect the spectral curve).

[0091] See Table 2, which shows the plating ratio parameters (Tooling) under the process conditions.

[0092] Table 2 250~330nm band film material plating ratio parameters

[0093] Tables 1 and 2 show the Tooling obtained under this process. Adding the designed film thickness (simulated plating thickness) can give the actual plating thickness (actual plating thickness) in Table 3 (which is an example of a portion of the film thickness).

[0094] Table 3 S1 actual coating thickness partial schematic

[0095] Since the diameter-to-thickness ratio of the dichroic mirror is too large, close to 20, S1 plating will have a significant impact on the surface shape of the original part. Therefore, the present invention innovatively adopts a solution to minimize the impact of S1 plating on the surface shape. Since S1 produces a film layer with greater stress when using the Ta ion source, 2 O5 With SiO 2 Therefore, an ion source is used for auxiliary evaporation when the first layer of S2 is deposited, and the film thickness is Ta in S1. 2 O 5 With SiO 2 SiO in combination 2 Thickness, after the first layer is completed, on the SiO 2 A pause of 10-20 minutes is set at the junction of the Hf film layer to ensure the firmness of the base film layer during Hf evaporation. 2 O 5 With SiO 2 In the combination, when coating each metal Hf film layer, the deposition rate is controlled to be 0.06-0.08nm / s, the oxygen filling amount is 60-80SCCM, and the film is formed by electron gun evaporation. 2 When depositing the film layer, the deposition rate is controlled to be 0.5-0.6nm / s, and the film is formed by electron gun evaporation. At the same time, the film system design software is used for optimization to obtain the design thickness of the S2 anti-reflection film. According to the Tooling and other information, the actual thickness (target plating thickness) is obtained as shown in Table 4.

[0096] Table 4 S2 actual coating thickness

[0097] See also Figures 5 to 7 . Figure 5 is a spectrum curve of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 29°, Figure 6 is a spectrum curve of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 50°, Figure 7 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 61°. Figures 3 to 7 In the above example, the parameters are different except for the incident angle ( Figure 5 The incident angle is 29°. Figure 6 The incident angle is 50°. Figure 7 The incident angle is 61°), and other parameters are the same. Light source: white light; Incident medium: air; Substrate refractive index: 1.46; Exit refractive index: 1.46; Detection: ideal state; Central wavelength: 550nm; First surface: front surface; There are three polarization states of light, average, S and P.

[0098] The software can calculate the design values ​​at 29°: Ravg=2.47%@250-650nm, Ravg=1.36%@1050-1100nm, Ravg=1.45%@1200-1400nm, 29deg; Ravg=4.07%@250-650nm, Ravg=2.06%@1050-1100nm, Ravg= 3.69%@1200-1400nm, 50deg; Ravg=7.78%@250-650nm, Ravg=5.25%@1050-1100nm, Ravg=7.7%@1200-1400nm, 61deg; all the above indicators can meet the requirements.

[0099] See also Figure 8 and Fig. 9 , Figure 8 It is a spectrum curve diagram of the residual reflectivity and transmittance of the dichroic mirror provided by the present invention at an incident angle of 29-61°, Fig. 9 It is a spectrum curve diagram of the residual reflectivity of the dichroic mirror provided by the present invention at an incident angle of 29-61°. According to the actual plating results, the above indicators can meet the indicator requirements.

[0100] See Table 5 and Table 6. Table 5 shows the surface data of S1 and S2 before plating, and Table 6 shows the surface data of S1 and S2 after plating. It can be seen from the data that the surface shape (RMS) of the product after plating is smaller than that before plating, which can meet the index requirements. In addition, since the S2 surface is plated with the same thickness of SiO by the "back-pull" method, 2 , so that the change in the surface shape of the product is reduced as much as possible to achieve a relatively excellent state. At the same time, the use of this technology reduces the processing cost and polishing pressure of the substrate surface during processing.

[0101] Table 5 Surface data of S1 and S2 before plating

[0102] Table 6 Surface data of S1 and S2 after plating

[0103] The dichroic optical film and the coating method thereof provided in the embodiment of the present invention provide a high reflectivity and high damage threshold laser film, which combines three materials, takes advantage of their strengths and makes up for their weaknesses according to their different optical properties and damage properties, and adopts Hf-Ta 2 O 5 -SiO 2 Multi-material film structure, that is, using Ta 2 O 5 -SiO 2The film stack meets the requirement of high reflectivity, and Hf-SiO is superimposed on the outermost part of the film stack. 2 The film stack can achieve high reflectivity requirements with fewer film layers, while improving the film's resistance to laser damage, and has strong practical value.

[0104] Through the description of the above implementation methods, those skilled in the art can clearly understand that each implementation method can be implemented by means of software plus a necessary general hardware platform, and of course, can also be implemented by hardware. Based on this understanding, the above technical solution is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a disk, an optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dichroic optical film, characterized in that: The dichroic mirror optical film consists of a tantalum pentoxide film layer, a silicon dioxide film layer and a metal hafnium film layer which are plated on the dichroic mirror.

2. The dichroic optical film according to claim 1, characterized in that: The dichroic mirror comprises a first coated surface and a second coated surface; The dichroic optical film comprises a beam splitting film coated on the first coating surface and an anti-reflection film coated on the second coating surface; The beam splitting film is composed of the tantalum pentoxide film layer, the silicon dioxide film layer and the metal hafnium film layer; The antireflection film is composed of the silicon dioxide film layer and the metal hafnium film layer.

3. The dichroic optical film according to claim 2, characterized in that: The beam splitting film is composed of a long-wave pass film system and a high-reflection film; The long-wave pass film is composed of the tantalum pentoxide film layer and the silicon dioxide film layer; The high reflective film is composed of the silicon dioxide film layer and the metal hafnium film layer.

4. The dichroic optical film according to claim 3, characterized in that: The beam splitting films are at least one layer of the long-wave pass film system and at least one layer of the high-reflection film in order from near to far from the first coating surface; The antireflection film comprises at least one silicon dioxide film layer and at least one metal hafnium film layer sequentially cross-plated on the second coating surface; the first film layer of the antireflection film plated on the second coating surface is a silicon dioxide film layer.

5. A method for coating a dichroic optical film according to any one of claims 1 to 4, characterized in that: include: Use the Hall ion source to etch the base film layer of the dichroic mirror for 10-15 minutes, and keep the background vacuum degree below 2*10 -3 Pascal, deposition temperature is 150-200 degrees Celsius, constant temperature for 10-20 minutes; A dichroic mirror optical thin film consisting of a tantalum pentoxide film layer, a silicon dioxide film layer and a metal hafnium film layer is plated on the surface of the dichroic mirror.

6. The method for coating a dichroic optical film according to claim 5, characterized in that: The dichroic mirror comprises a first coating surface and a second coating surface, the dichroic mirror optical film comprises a beam splitter film coated on the first coating surface and an anti-reflection film coated on the second coating surface, and the beam splitter film is composed of a long-wave pass film system and a high-reflection film; The method of coating a dichroic mirror optical film composed of a tantalum pentoxide film layer, a silicon dioxide film layer and a metal hafnium film layer on the surface of the dichroic mirror comprises: Sequentially coating the long-wave pass film system and the high-reflection film on the first coating surface; The antireflection film is plated on the second plated surface.

7. The method for coating a dichroic optical film according to claim 6, characterized in that: The long-wave pass film is composed of the tantalum pentoxide film layer and the silicon dioxide film layer, and the high-reflection film is composed of the silicon dioxide film layer and the metal hafnium film layer; The step of sequentially coating the long-wave pass film system and the high-reflection film on the first coating surface comprises: When the tantalum pentoxide film layer in the long-wave pass film system is plated, an ion source is used for auxiliary evaporation, and the deposition rate is controlled to be 0.2-0.3 nanometers per second, and the oxygen filling amount is 10-20 standard cubic centimeters per minute; when the silicon dioxide film layer in the long-wave pass film system is plated, an ion source is used for auxiliary evaporation, and the deposition rate is controlled to be 0.5-0.6 nanometers per second; After the long-wave pass film system is plated, the plating is suspended for 10-20 minutes and then the high-reflection film is plated; When the metal hafnium film layer in the high-reflective film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.06-0.08 nanometers per second, and the oxygen filling amount is 60-80 standard cubic centimeters per minute; when the silicon dioxide film layer in the high-reflective film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.5-0.6 nanometers per second.

8. The method for coating a dichroic optical film according to claim 6, characterized in that: The antireflection film is composed of the silicon dioxide film layer and the metal hafnium film layer; The step of coating the antireflection film on the second coating surface comprises: Coating a first silicon dioxide film layer of the antireflection film on the second coating surface; After the first silicon dioxide film layer is deposited, the deposition is suspended for 10-20 minutes before depositing the metal hafnium film layer and other silicon dioxide film layers of the anti-reflection film, wherein the other silicon dioxide film layers are any silicon dioxide film layers in the anti-reflection film except the first silicon dioxide film layer; When the metal hafnium film layer in the antireflection film is plated, an electron gun is used for auxiliary evaporation, and the deposition rate is controlled to be 0.06-0.08 nanometers per second, and the oxygen filling amount is 60-80 standard cubic centimeters per minute; When the silicon dioxide film layer in the antireflection film is plated, the deposition rate is controlled to be 0.5-0.6 nanometers per second, and an ion source is used to assist in evaporation deposition of the first silicon dioxide film layer, and an electron gun is used to assist in evaporation deposition of the other silicon dioxide film layers.

9. The method for coating a dichroic optical film according to claim 6, characterized in that: Before the long-wave pass film system and the high-reflection film are sequentially plated on the first plated surface, the method further includes: Obtaining a plating ratio parameter and a plating target corresponding to the dichroic mirror; According to the plating target and the plating ratio parameter, respectively determining the target plating thickness of each tantalum pentoxide film layer, the target plating thickness of each silicon dioxide film layer, and the target plating thickness of each metal hafnium film layer in the beam splitting film; According to the target coating thickness of each silicon dioxide film layer in the long-wave pass film system, the coating target and the coating ratio parameter, the target coating thickness of each silicon dioxide film layer and the target coating thickness of each metal hafnium film layer in the anti-reflection film are determined respectively.

10. The method for coating a dichroic optical film according to claim 9, characterized in that: The target coating thickness of each silicon dioxide film layer and the target coating thickness of each metal hafnium film layer in the antireflection film are determined according to the target coating thickness of each silicon dioxide film layer in the long-wave pass film system, the coating target and the coating ratio parameter, including: Calculating the sum of the target coating thicknesses of the silicon dioxide film layers in the long-wave pass film system to obtain the target coating thickness of the first silicon dioxide film layer in the anti-reflection film; According to the target coating thickness of the first silicon dioxide film layer, the coating target and the coating ratio parameter, the target coating thickness of each other silicon dioxide film layer in the anti-reflection film and the target coating thickness of each metal hafnium film layer are determined respectively, and the other silicon dioxide film layer is any silicon dioxide film layer in the anti-reflection film except the first silicon dioxide film layer.

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