A color separation film that reflects visible light to short-wave infrared and transmits wide-spectrum infrared and a manufacturing method thereof

Abstract

The present invention relates to a dichroic filter that reflects visible light to shortwave infrared and transmits a broad spectrum of infrared light, and its manufacturing method. The dichroic filter uses a flat germanium substrate and a dichroic film system similar to a longwavepass filter. Germanium, zinc sulfide, and fluoride are used as the high and low refractive index materials for different reflective film stacks. A dichroic film is designed on the front surface of the substrate, combining different reflective film stacks to achieve broadband high reflectivity. An optimized matching layer reduces transmission passband ripple. A broad spectrum antireflection film is designed on the back surface of the substrate to achieve high transmittance in the transmission channel while minimizing residual reflection and eliminating stray light. During the preparation process, the dichroic filter utilizes appropriate deposition rates, substrate temperatures, and ion-assisted deposition of localized film layers to reduce thin film absorption and improve the environmental reliability of the filter. Measured reflectivity and transmittance curves show that the filter has high reflectivity in the 0.4-1.7 μm band and high transmission in the 2.1-2.4 μm shortwave infrared band and the 3.5-14 μm mid- and longwave infrared bands. It is suitable for spectral separation in visible-to-infrared multi-channel remote sensing systems.

Description

Technical Field

[0001] The invention relates to the technical field of optical films, in particular to a color separation film capable of reflecting visible light to short-wave infrared and transmitting wide-spectrum infrared, and a manufacturing method thereof. Background Art

[0002] In multi-channel imagers used for space remote sensing, the use of wide-spectrum color separation filters based on all-dielectric reflective film stacks for spectral separation can highly reflect light from the visible to shortwave infrared bands, allowing it to enter the shortwave optical path and be received by shortwave detectors for imaging. Simultaneously, they highly transmit light from the mid- and longwave infrared bands, allowing it to be received by appropriate infrared detectors for imaging. Compared to spectral separation methods based on metal-induced transmission, this method based on all-dielectric reflective film stacks can improve the optical transmission efficiency of the visible to shortwave infrared channel, which is beneficial for improving the imaging quality of systems with large fields of view and long focal lengths in this region. Furthermore, this color separation method facilitates optical path optimization, eliminating rear optical path lens groups, reducing optical transmission losses in the transmission path, and reducing the weight of the optical system. Such color separation filters can be used in common-aperture imaging systems with dual visible and infrared detectors, playing an important role in low-light-level night vision imaging, thermal infrared imaging, and all-weather rescue and security operations in adverse weather conditions such as rain, snow, fog, and haze.

[0003] With the further development of ultra-wideband spectral imaging technology for space remote sensing, the number of spectral channels required to be covered is increasing, and the image quality requirements for the visible and near-infrared bands are becoming increasingly stringent. As a result, color separation methods using long-wavepass filter structures in optical systems have attracted considerable attention. Currently, this color separation method suffers from insufficient coverage of the band required for efficient transmission, resulting in low utilization of the system's spectral channel resources. Furthermore, due to its complex film structure and the number of film layers, which can reach dozens, its spatial reliability needs to be improved. To address these issues, new color separation filter designs and improved manufacturing processes are needed. However, there are no reports of wide-spectrum color separation filters that achieve continuous high reflection in the 0.4-1.7μm reflection band and continuous high transmission in the 2.1-2.4μm short-wave infrared band and the 3.5-14μm mid-wave infrared band. Summary of the Invention

[0004] The purpose of the present invention is to provide a color separation film that reflects visible light to short-wave infrared and transmits wide-spectrum infrared and a method for manufacturing the same, thereby solving the problem that the existing color separation method has insufficient coverage of the band for efficient transmission, resulting in low utilization of the system's spectral channel resources.

[0005] To achieve the above object, the technical solution of the present invention is:

[0006] A dichroic film that reflects visible light to short-wave infrared and transmits wide-spectrum infrared comprises a substrate, a wide-spectrum dichroic film, and a wide-spectrum anti-reflection film. The wide-spectrum dichroic film is disposed on the upper surface of the substrate, and the wide-spectrum anti-reflection film is disposed on the lower surface of the substrate. The wide-spectrum dichroic film comprises a front matching layer, a reflective film stack, and a rear matching layer. The composition is as follows:

[0007] Base / A1(R1) a (R2) 6 (R3) b (R4) 7 A2 / Air

[0008] Among them, A1 is the front matching layer, R1, R2, R3, and R4 are four reflective film stacks, A2 is the rear matching layer, index a is the period number of the R1 reflective film stack, and index b is the period number of the R3 reflective film stack.

[0009] The substrate is made of germanium; the R1 reflective film stack is made of alternating dielectric layers of germanium and fluoride; the R2, R3 and R4 reflective film stacks are made of alternating dielectric layers of zinc sulfide and fluoride.

[0010] The fluoride in the alternating dielectric layer is a low-refractive-index material with a refractive index of 1.41 to 1.57; the fluoride in the alternating dielectric layer is calcium fluoride, ytterbium fluoride, or yttrium fluoride.

[0011] The alternating dielectric layer is a material with a low extinction coefficient in a wide band, and the extinction coefficient is lower than 0.002 in the visible and near-infrared bands, and lower than 0.018 in the long-wave infrared band.

[0012] The wide-spectrum anti-reflection coating is composed of dielectric layers of germanium, zinc sulfide and fluoride. Germanium is the high-refractive-index material in the wide-spectrum anti-reflection coating, zinc sulfide is the medium-refractive-index material in the wide-spectrum anti-reflection coating, and fluoride is the low-refractive-index material in the wide-spectrum anti-reflection coating.

[0013] The method for manufacturing a color separation film that reflects visible light to short-wave infrared and transmits wide-spectrum infrared includes the following steps: step 1, bombarding a substrate with an ion beam in a box-type vacuum coating device with a diffusion pump system; step 2, using electron beam evaporation to deposit alternating dielectric layers of germanium and fluoride to form an R1 reflective film stack; step 3, depositing alternating dielectric layers of zinc sulfide and fluoride to form three reflective film stacks R2, R3 and R4.

[0014] The substrate is germanium or zinc selenide.

[0015] In step three, the zinc sulfide film layer is formed by resistance heating evaporation deposition.

[0016] The fluoride is ytterbium fluoride.

[0017] During production, the temperature of the substrate is controlled at 170°C to 200°C.

[0018] The advantages of the present invention are: 1. The color separation film adopts the structure of a long-wave pass filter, and is designed to use four reflective film stacks to meet wide reflection requirements. According to the optical properties of different materials, different reflective film stacks are formed by selecting the best combination to extend the reflection band from the visible near-infrared band to the short-wave infrared band, obtain high reflectivity in the wide band of 0.4-1.7μm, and add matching layers at both ends of the dichroic film reflective film stack. By optimizing the thickness of the matching layers, high transmittance in the short-wave infrared and medium- and long-wave bands is achieved; 2. The substrate temperature is controlled at 170℃~200℃ to avoid the increase of fluoride absorption in the long-wave infrared band, ensuring the transmittance of the dichroic film in the 12-14μm band. The film layer has good firmness and can obtain highly reliable dichroic film; 3. The influence of zinc sulfide film's dispersion loss on the reflection band waveform in the visible light band of 0.4-0.6μm is reduced, and the absorption of fluoride film in the long-wave infrared band of 12-14μm is reduced, achieving high transmission efficiency in multiple continuous bands from visible light to long-wave infrared, good reliability and stable product performance; BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the film structure of the color separation sheet of the present invention;

[0020] Figure 2 is the measured reflectance spectrum curve of the color separation sheet of the present invention;

[0021] Figure 3 is the measured transmittance spectrum curve of the color separation sheet of the present invention;

[0022] In the figure: 1-wide spectrum dichroic film; 2-substrate; 3-wide spectrum anti-reflection film; 4-incident light beam; 5-reflected light beam; 6-transmitted light beam. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings, which are for illustrative purposes only and are not to be construed as limiting the present invention.

[0024] To more concisely illustrate this embodiment, some components well known to those skilled in the art but not relevant to the main content of this invention may be omitted from the drawings or descriptions. In addition, for ease of description, some components may be omitted, enlarged, or reduced in size in the drawings, but they do not represent the dimensions or entire structure of the actual product.

[0025] The present invention discloses a color separation sheet that reflects visible light to short-wave infrared and transmits wide-spectrum infrared. Figure 1 As shown, it includes a substrate 2, a wide spectrum dichroic film 1 and a wide spectrum anti-reflection film 3. The wide spectrum dichroic film 1 is arranged on the upper surface of the substrate 2, and the wide spectrum anti-reflection film 3 is arranged on the lower surface of the substrate 2. The wide spectrum dichroic film 1 includes a front matching layer, a reflective film stack and a rear matching layer, and its composition is as follows:

[0026] Base / A1(R1) a (R2) 6 (R3) b (R4) 7 A2 / Air

[0027] Among them, A1 is the front matching layer, R1, R2, R3, and R4 are four reflective film stacks, A2 is the rear matching layer, index a is the period number of the R1 reflective film stack; index b is the period number of the R3 reflective film stack.

[0028] The substrate 2 is made of germanium, i.e., a germanium substrate; the R1 reflective film stack is composed of alternating dielectric layers of germanium and fluoride; and the R2, R3 and R4 reflective film stacks are composed of alternating dielectric layers of zinc sulfide and fluoride.

[0029] The fluoride in the alternating dielectric layer is a low refractive index material with a refractive index of 1.41 to 1.57; the fluoride in the alternating dielectric layer is calcium fluoride, ytterbium fluoride, or yttrium fluoride. Preferably, the fluoride is ytterbium fluoride.

[0030] The alternating dielectric layer is a material with a low extinction coefficient in a wide band, and the extinction coefficient is lower than 0.002 in the visible and near-infrared bands, and lower than 0.018 in the long-wave infrared band.

[0031] The wide-spectrum anti-reflection film 3 is composed of dielectric layers of germanium, zinc sulfide and fluoride. Germanium is a high-refractive-index material in the wide-spectrum anti-reflection film 3, zinc sulfide is a medium-refractive-index material in the wide-spectrum anti-reflection film 3, and fluoride is a low-refractive-index material in the wide-spectrum anti-reflection film 3.

[0032] Germanium, zinc sulfide, and fluoride serve as the high-refractive-index and low-refractive-index materials, respectively, for different reflective film stacks. The reflection band is very wide, from 0.4 to 1.7 μm. A single reflective film stack cannot meet the broadband reflection requirements. Therefore, four reflective film stacks are used in the wide-spectrum dichroic film 1. By adding matching layers at both ends of the reflective film stacks, reflection is achieved from the visible to the short-wave infrared band, while transmission is achieved in the 2.1 to 2.4 μm and 3.5 to 14 μm infrared bands. A wide-spectrum anti-reflection film 3 is designed on the lower surface of the substrate 2, using germanium, zinc sulfide, and fluoride as the high-refractive-index material, medium-refractive-index material, and low-refractive-index material, respectively. By optimizing the film layers, high transmittance is achieved in the 2.1 to 14 μm band.

[0033] The implementation of the color separation sheet of the present invention includes the following steps:

[0034] First, the structure of the membrane system

[0035] The reflective film stack R is constructed according to the reflection band and the central wavelength, and the bandwidth of the reflection band is expanded. The film structure of the wide spectrum dichroic film 1 is:

[0036] Base / A1(0.78H1.62L0.78H) a (0.56M0.92L0.56M) 6 (0.47M0.68L0.47M) b

[0037] (0.32M0.56L0.32M) 7 A2 / Air

[0038] Among them: A1 is the front matching layer, and the structure of A1 is k1Mk2Hk3Mk4Hk5Mk6H; A2 is the back matching layer, and the structure of A2 is t1Mt2Lt3Mt4Lt5Mt6Lt7M.

[0039] The film system of the wide spectrum anti-reflection film is:

[0040] base

[0041] / 0.283M3.55H0.787M3.265H1.527M2.381H2.477M1.438H3.823M0.531L2.735M1.08L3.24M2.382L1.48M6.476L0.21M / Air

[0042] Wherein: index a is 4 or 5; index b is 6 or 7; H represents a germanium film layer with an optical thickness of λ0 / 4, L represents a fluoride film layer with an optical thickness of λ0 / 4, M represents a zinc sulfide film layer with an optical thickness of λ0 / 4, λ0 is the center wavelength, k1, k2, k3, k4, k5, k6, t1, t2, t3, t4, t5, t6, and t7 are the proportional coefficients of the thickness of each film layer.

[0043] The present invention provides a method for fabricating a dichroic film that reflects visible light to short-wave infrared and transmits a wide spectrum of infrared light. Step 1: ion beam bombarding a substrate 2 in a chamber-type vacuum coating apparatus equipped with a diffusion pump system; the substrate 2 is germanium or zinc selenide, preferably a germanium substrate. Step 2: electron beam evaporation is used to deposit alternating dielectric layers of germanium and fluoride to form an R1 reflective film stack; the fluoride is preferably ytterbium fluoride.

[0044] Step 3: Deposit alternating layers of zinc sulfide and fluoride to form three reflective film stacks R2, R3, and R4. The zinc sulfide film layers are formed by resistance heating evaporation deposition.

[0045] Some film layers are deposited using ion beam assisted deposition, with a Mark II ion source and specific parameters: anode voltage 130V~150V, anode current 3A~5A.

[0046] Analysis of film material test results shows that when the substrate 2 temperature exceeds 200°C, zinc sulfide undergoes significant reverse evaporation, hindering thin film deposition on the substrate 2. Furthermore, when the substrate 2 temperature is below 170°C, fluoride absorption in the long-wave infrared band increases, affecting the transmittance of the dichroic film in the 12-14μm band. Therefore, controlling the substrate 2 temperature between 170°C and 200°C ensures excellent film durability and produces highly reliable dichroic films.

[0047] Therefore, during the production, the temperature of the substrate 2 is controlled at 170°C to 200°C.

[0048] Combined with attachment Figure 1-3 The specific embodiments of the present invention are described in further detail.

[0049] The substrate 2 is made of a germanium sheet, and the fluoride of the low refractive index dielectric layer in this example is ytterbium fluoride.

[0050] According to technical requirements, a wide-spectrum dichroic film 1 is fabricated on the upper surface of a germanium substrate 2, and a wide-spectrum anti-reflection film 3 is fabricated on the lower surface of the substrate 2. The wide-spectrum dichroic film 1 adopts the structure of a long-wavepass filter and is designed with four reflective film stacks to achieve wide reflection. Different reflective film stacks are selected based on the optical properties of different materials to extend the reflection band from the visible near-infrared band to the short-wave infrared band, achieving high reflectivity in the wide wavelength band of 0.4 to 1.7 μm. Matching layers are added to both ends of the reflective film stack of the wide-spectrum dichroic film 1. By optimizing the thickness of the matching layers, high transmission is achieved in the short-wave infrared and mid- and long-wave bands. The design of the wide-spectrum dichroic film 1 takes into account stress matching between the film layers and the feasibility of process control. A wide-spectrum anti-reflection film 3 is designed on the lower surface of the germanium substrate 2. During the film system optimization, the thickness of individual key layers is controlled to reduce the reflectivity of the lower surface of the substrate 2 and improve the transmittance from the short-wave infrared to the long-wave infrared band.

[0051] Since germanium materials absorb in the near-infrared and short-wave infrared, the thicker the germanium film, the greater the absorption in the short-wave infrared channel, and the lower the reflectivity. Also, because ytterbium fluoride materials have non-negligible absorption in the wavelength band greater than 12μm, the degree of absorption is directly related to the film thickness. Therefore, the design of the wide-spectrum dichroic film 1 also needs to comprehensively consider the number of layers and thickness of the entire film system.

[0052] The first one is when the number of membrane stack cycles a=4,b=7,

[0053] The film system is optimized by optical thin film design software, the thickness of a few key layers is controlled, and the film layer with a thickness ratio coefficient of zero is removed. The resulting film system is: substrate

[0054] / 0.71M3.225H1.141M2.638H2.045M1.127H(0.78H1.62L0.78H)4 (0.56M0.92L0.56M) 6 (0.47M0.68L0.47M) 7 (0.32M0.56L0.32M) 7 0.805L1.513M2.885L0.548M5.339L0.22M / air;

[0055] The design results achieve high reflectivity in the visible and near-infrared bands, and high transmittance in the short-wave infrared and medium- and long-wave infrared bands.

[0056] The second type is when the number of membrane stack cycles a=4,b=6,

[0057] The film system is optimized by software to control the thickness of very few key layers. The obtained film system is: substrate

[0058] / 0.804M2.937H1.332M2.502H2.398M0.997H(0.78H1.62L0.78H) 4 (0.56M0.92L0.56M) 6 (0.47M0.68L0.47M) 6 (0.32M0.56L0.32M) 7 2.203L1.298M0.397L0.275M6.021L0.228M / air;

[0059] The design results achieve high reflectivity in the visible and near-infrared bands, and high transmittance in the short-wave infrared and medium- and long-wave infrared bands.

[0060] The third type is when the number of membrane stack cycles a=5,b=6,

[0061] The film system is optimized by optical thin film design software, the thickness of a few key layers is controlled, and the film layer with a thickness ratio coefficient of zero is removed. The resulting film system is: substrate

[0062] / 0.683M3.978H1.203M2.275H1.926M1.491H(0.78H1.62L0.78H) 5 (0.56M0.92L0.56M) 6 (0.47M0.68L0.47M) 6 (0.32M0.56L0.32M) 7 1.594L0.2M1.811L0.55M4.023L0.183M / air;

[0063] The design results achieve high reflectivity in the visible and near-infrared bands, and high transmittance in the short-wave infrared and medium- and long-wave infrared bands.

[0064] The fourth type, when the number of membrane stack cycles a=5,b=7,

[0065] The film system is optimized by software, the thickness of a few key layers is controlled, and the film layer with a thickness ratio coefficient of zero is removed. The resulting film system is: substrate

[0066] / 1.179M2.448H1.619M1.409H(0.78H1.62L0.78H) 5 (0.56M0.92L0.56M) 6 (0.47M0.68L0.47M) 7 (0.32M0.56L0.32M) 7 1.388L0.4M3.304L0.2M / air;

[0067] The design results achieve high reflectivity in the visible and near-infrared bands, and high transmittance in the short-wave infrared and medium- and long-wave infrared bands.

[0068] Taking into account the absorption of germanium thin films in the near-infrared and short-wave infrared bands, the certain absorption of ytterbium fluoride in the long-wave infrared, and the reliability of the film system, the wide-spectrum dichroic film 1 on the upper surface of the germanium substrate was actually produced using the film system of the third type mentioned above. Combined with the wide-spectrum anti-reflection film 3 system on the lower surface of the germanium substrate, the final complete film system is:

[0069] S0 / 0.183M4.023L0.55M1.811L0.2M1.594L(0.32M0.56L0.32M) 7 (0.47M0.68L0.47M) 6 (0.56M0.92L0.56M) 6 (0.78H1.62L0.78H) 5 1.491H1.926M2.275H1.203M3.978H0.683M / S1 / 0.283M3.55H0.787M3.265H1.527M2 .381H2.477M1.438H3.823M0.531L2.735M1.08L3.24M2.382L1.48M6.476L0.21M / S0

[0070] Where: S1 is the germanium substrate, S0 is air, H represents a germanium film layer with an optical thickness of λ0 / 4, M represents a zinc sulfide film layer with an optical thickness of λ0 / 4, L represents an ytterbium fluoride film layer with an optical thickness of λ0 / 4, λ0 is the center wavelength, indices 4, 5, 6, and 7 are the period numbers of each reflective film stack, and the numbers before M, H, and L are the proportional coefficients of the thickness of each film layer.

[0071] In this embodiment, the substrate temperature of the color separation plate is 180°C, and electron beam evaporation deposition is used to form germanium and ytterbium fluoride films. By adopting a pre-melting process and selecting an appropriate deposition rate, the absorption of the germanium film in the short-wave infrared region and the absorption of the ytterbium fluoride film in the long-wave infrared band of 12 to 14 μm are reduced. The zinc sulfide film is prepared by resistance evaporation deposition, and local film layers are deposited using ion beam assisted deposition.

[0072] from Figure 2 It can be seen that this color separation film has high reflection in the 0.4-1.7μm band, and its average reflectivity is calculated to be 94%. Figure 3 It can be seen that the color separation film has high transmittance in the short-wave infrared band of 2.1-2.4 μm, and its average transmittance is calculated to be 91.5%. It also has high transmittance in the medium- and long-wave infrared band of 3.5-14 μm, and its average transmittance is calculated to be 92%.

[0073] The color separation sheet of the present invention has good reliability and stable optical and physical properties, and can be used for spectral color separation of space remote sensing imagers, and is also suitable for visible-infrared dual-detector common aperture imaging systems.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. That is, any equivalent changes and modifications made according to the content of the patent application of the present invention should fall within the technical scope of the present invention.

Claims

1. A color separation film that reflects visible light to short-wave infrared and transmits a wide spectrum of infrared light, characterized by: The invention comprises a substrate (2), a wide spectrum dichroic film (1) and a wide spectrum anti-reflection film (3), wherein the wide spectrum dichroic film (1) is arranged on the upper surface of the substrate (2), and the wide spectrum anti-reflection film (3) is arranged on the lower surface of the substrate (2); the wide spectrum dichroic film (1) comprises a front matching layer, a reflective film stack and a rear matching layer, and its composition is as follows: Base / A1(R1) a (R2) 6 (R3) b (R4) 7 A2 / Air Among them, A1 is the front matching layer, R1, R2, R3, and R4 are four reflective film stacks, A2 is the rear matching layer, index a is the period number of the R1 reflective film stack, and index b is the period number of the R3 reflective film stack; The substrate (2) is made of germanium; the R1 reflective film stack is made of alternating dielectric layers of germanium and fluoride; the R2, R3 and R4 reflective film stacks are made of alternating dielectric layers of zinc sulfide and fluoride; According to the reflection band and the central wavelength, a reflection film stack is constructed to expand the bandwidth of the reflection band. The film structure of the wide spectrum dichroic film (1) is: Base / A1(0.78H1.62L0.78H) a (0.56M0.92L0.56M) 6 (0.47M0.68L0.47M) b (0.32M0.56L0.32M) 7 A2 / Air Among them: A1 is the front matching layer, and the structure of A1 is k1Mk2Hk3Mk4Hk5Mk6H; A2 is the back matching layer, and the structure of A2 is t1Mt2Lt3Mt4Lt5Mt6Lt7M, The film system of the wide spectrum anti-reflection film (3) is: Base / 0.283M3.55H0.787M3.265H1.527M2.381H2.477M1.438H3.823M0.531L2.735M1.08L3.24M2.382L1.48M6.476L0.21M / Air Among them, the index a is 4 or 5; the index b is 6 or 7; H represents a germanium film layer with an optical thickness of λ0 / 4, L represents a fluoride film layer with an optical thickness of λ0 / 4, M represents a zinc sulfide film layer with an optical thickness of λ0 / 4, λ0 is the center wavelength, and k1, k2, k3, k4, k5, k6, t1, t2, t3, t4, t5, t6, and t7 are the proportional coefficients of the thickness of each film layer.

2. The color separation filter that reflects visible light to short-wave infrared and transmits wide-spectrum infrared according to claim 1, characterized in that: The fluoride in the alternating dielectric layer is a low-refractive-index material with a refractive index of 1.41 to 1.57; the fluoride in the alternating dielectric layer is calcium fluoride, ytterbium fluoride, or yttrium fluoride.

3. The color separation filter that reflects visible light to short-wave infrared and transmits wide-spectrum infrared according to claim 1, characterized in that: The alternating dielectric layer is a material with a low extinction coefficient in a wide band, and the extinction coefficient is lower than 0.002 in the visible and near-infrared bands, and lower than 0.018 in the long-wave infrared band.

4. The color separation filter according to claim 1, which reflects visible light to short-wave infrared and transmits wide-spectrum infrared, characterized in that: The wide-spectrum anti-reflection film (3) is composed of dielectric layers of germanium, zinc sulfide and fluoride, wherein germanium is a high-refractive-index material in the wide-spectrum anti-reflection film (3), zinc sulfide is a medium-refractive-index material in the wide-spectrum anti-reflection film (3), and fluoride is a low-refractive-index material in the wide-spectrum anti-reflection film (3).

5. The method for producing a color separation film that reflects visible light to short-wave infrared and transmits wide-spectrum infrared according to any one of claims 1 to 4, characterized in that: Step 1: bombarding a substrate (2) with an ion beam in a box-type vacuum coating device with a diffusion pump system; step 2: depositing germanium and fluoride alternating dielectric layers using electron beam evaporation to form an R1 reflective film stack; step 3: depositing zinc sulfide and fluoride alternating dielectric layers to form three reflective film stacks R2, R3 and R4.

6. The method for producing a color separation film that reflects visible light to short-wave infrared and transmits a wide spectrum of infrared according to claim 5, characterized in that: The substrate (2) is germanium or zinc selenide.

7. The method for producing a color separation film that reflects visible light to short-wave infrared and transmits a wide spectrum infrared according to claim 5, characterized in that: In step three, the zinc sulfide film layer is formed by resistance heating evaporation deposition.

8. The method for manufacturing a color separation film that reflects visible light to short-wave infrared and transmits a wide spectrum infrared according to claim 5, characterized in that: The fluoride is ytterbium fluoride.

9. The method for manufacturing a color separation film that reflects visible light to short-wave infrared and transmits a wide spectrum infrared according to claim 5, characterized in that: During the production, the temperature of the substrate (2) is controlled at 170°C to 200°C.

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