A multilayer optical film, methods of making the same, and imaging devices

Abstract

The application discloses a kind of multilayer optical film and its preparation method, imaging device, including providing optical glass substrate, anti-reflection layer is deposited on optical glass substrate, anti-reflection layer is designed using split film design algorithm, and designed split pattern is transferred to anti-reflection layer;High damage threshold protection layer is deposited on anti-reflection layer, heat management layer is deposited on high damage threshold protection layer, reflective layer is deposited on heat management layer by evaporation, form multilayer film structure, the interface bonding force between multilayer film structure is improved by annealing treatment to the multilayer film structure formed, set annealing condition is preset temperature, to obtain multilayer optical film;Through the optimization design of whole preparation process, and give consideration to anti-laser damage capacity, heat management layer provides thermal stability, reflective layer improves the efficiency of optical system, to manufacture high performance, multifunctional multilayer optical film, adapt to the high requirements of laser display system.

Description

Technical Field

[0001] This invention relates to the field of optical display technology, and in particular to a multilayer optical film, its preparation method, and an imaging device. Background Technology

[0002] With the rapid development of laser display technology, laser imaging display systems have demonstrated enormous potential in high-brightness and high-definition applications. Due to its vibrant colors, high brightness, and superior resolution, laser display technology has been widely used in various displays, including televisions, projectors, and computer monitors. However, in laser display systems, the performance of the optical film is crucial to the overall system performance. Especially under high-power laser irradiation, ensuring the stability of the optical film, improving light transmittance, reducing heat loss, and preventing laser damage have become pressing technical challenges for the industry.

[0003] Currently, most optical thin-film products on the market employ traditional anti-reflective and protective film structures. These films are typically prepared using physical vapor deposition (PVD) or chemical vapor deposition (CVD) techniques. For example, traditional anti-reflective films often use magnesium fluoride or silicon dioxide to reduce light reflection loss and improve transmittance. However, existing anti-reflective films often lack sufficient laser damage resistance when exposed to high-power lasers. This can lead to damage during use, severely impacting the long-term stability of the display system. While some technologies enhance the damage resistance of the film by adding a protective film, these films typically sacrifice transmittance and thermal stability, making it difficult to achieve an optimal balance in laser display systems. In summary, existing optical film products generally suffer from poor laser damage resistance, insufficient thermal stability, and low optical efficiency.

[0004] Therefore, it is necessary to improve the existing optical thin film product technology to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a multilayer optical film, its preparation method, and an imaging device to solve the above-mentioned technical problems.

[0006] To achieve this objective, the present invention adopts the following technical solution:

[0007] A method for preparing a multilayer optical film, comprising:

[0008] Step S1: Provide an optical glass substrate, and deposit an anti-reflection layer on the optical glass substrate using reactive magnetron sputtering technology. The anti-reflection layer is made of magnesium fluoride or silicon dioxide material to form an anti-reflection layer with high transparency.

[0009] Step S2: Use a beam splitter design algorithm to design a pattern for the anti-reflection layer, and transfer the designed beam splitter pattern onto the anti-reflection layer;

[0010] Step S3: Deposit a high damage threshold protective layer on the anti-reflection layer, wherein the high damage threshold protective layer is made of silicon nitride or aluminum nitride.

[0011] Step S4: Deposit a thermal management layer on the high damage threshold protective layer. The thermal management layer is made of metal oxide or nitride with high thermal conductivity to improve the thermal stability of the film.

[0012] Step S5: A reflective layer is deposited on the thermal management layer by evaporation to form a multilayer film structure. The reflective layer is made of a metallic material such as aluminum or silver to provide total reflection.

[0013] Step S6: Anneal the formed multilayer film structure and set the annealing condition to a preset temperature to improve the interfacial bonding force between the multilayer film structures and obtain a multilayer optical film.

[0014] Optionally, the fabrication process of the optical glass substrate is as follows:

[0015] Step S101: Determine the required optical glass composition according to the design requirements and select suitable raw materials for manufacturing optical glass;

[0016] Step S102: Mix the selected raw materials according to a preset ratio and melt them into glass liquid under high temperature conditions, typically 1500°C to 2000°C.

[0017] Step S103: Molten glass liquid is formed into an optical glass substrate with a preset shape through a mold; Step S104: The optical glass substrate is surface treated by chemical polishing, and then the substrate surface is cleaned by ultrasonic cleaning to remove surface contaminants.

[0018] Optionally, step S1 specifically includes:

[0019] Step S11: Fix the clean transparent glass substrate into the deposition chamber and perform a pre-inspection of the reactive magnetron sputtering equipment;

[0020] Step S12: Place the cleaned optical glass substrate in a reactive magnetron sputtering device to begin surface pretreatment. Specifically, use low-energy argon plasma to treat the substrate surface to remove residual contaminants and activate the substrate surface. The power during the treatment is 100W, the argon flow rate is set to 20sccm, and the treatment time is 3 minutes.

[0021] Step S13: In the reactive magnetron sputtering process, magnesium fluoride or silicon dioxide is selected as the anti-reflection layer material, oxygen is used as the reactive gas, and the thickness of the film is controlled by adjusting the sputtering power, gas flow rate and working pressure to perform reactive magnetron sputtering deposition.

[0022] Step S14: During reactive magnetron sputtering, the distance between the magnesium fluoride or silicon dioxide target and the optical glass substrate is adjusted to optimize the deposition uniformity of the thin film.

[0023] Step S15: After the deposition process is completed, the film thickness is measured in real time using an optical film thickness gauge, and the transmittance of the film is tested using a UV-Vis spectrophotometer to ensure that the film transmittance reaches more than 90%.

[0024] Optionally, step S2 specifically includes:

[0025] Step S21: Use optical design software to model the optical performance of the anti-reflection layer, and use a beam splitting film design algorithm to ensure that the designed beam splitting pattern can effectively improve the light transmittance and reduce reflection. Select the corresponding material refractive index and film thickness to meet the preset wavelength range requirements.

[0026] Step S22: In the process of designing the spectral pattern, by adjusting the thickness distribution, number of layers and optical path difference of the film, the designed anti-reflection pattern can generate multiple interferences within the required spectral range, thereby achieving a wide-band or narrow-band anti-reflection effect.

[0027] S23. After the beam splitting pattern design is completed, a digital pattern file is generated and converted into a photolithography template. The designed beam splitting pattern is then transferred to the anti-reflection layer on the optical glass substrate using patterned exposure technology.

[0028] S24. A scanning electron microscope is used to examine the pattern structure after the pattern transfer, to detect whether there is any distortion or error in the pattern structure, and to make corrections by adjusting the exposure intensity or exposure time based on the deviation results.

[0029] S25. After the pattern transfer is completed, reactive ion etching technology is used to select an etching gas for dry etching to remove unwanted film layers and retain the designed spectroscopic pattern. The power during the etching process is set to 150W, the gas flow rate is 15sccm, and the working pressure is controlled at 1Pa.

[0030] Optionally, step S3 specifically includes:

[0031] Step S31: Ultrasonic cleaning is performed using a mixture of deionized water and isopropanol for 5 minutes to remove residual impurities on the optical substrate surface for surface cleaning.

[0032] Step S32: Transfer the cleaned optical substrate into the reactive magnetron sputtering apparatus for the deposition process and run it according to the set initial sputtering parameters;

[0033] Step S33: During the deposition process, the gas flow rate and power parameters are dynamically adjusted according to the reactivity of the film and the deposition rate to optimize the physical and optical properties of the film.

[0034] Step S34: After deposition is completed, the transmittance of the deposited high damage threshold protective layer is tested using a UV-Vis spectrophotometer to ensure that the film has good transmittance performance in the required wavelength range.

[0035] Optionally, step S4 specifically includes:

[0036] Step S41: Transfer the optical substrate to a metal oxide or nitride deposition device with high thermal conductivity to prepare for the deposition of the thermal management layer. The initial deposition settings are: sputtering power of 350W, oxygen flow rate of 15sccm, and working pressure of 0.3Pa.

[0037] S42, during the deposition process, the film thickness is monitored in real time, the growth rate of the film is tracked by an optical film thickness gauge, and the deposition rate is adjusted to control the thickness of the thermal management layer between 50 and 150 nanometers.

[0038] S43, during the deposition of the thermal management layer, the nitrogen flow rate is controlled at 10 sccm and the oxygen flow rate at 5 sccm to adjust the composition of the film layer.

[0039] S44. After deposition, the transmittance of the thermal layer is tested using a UV-Vis spectrophotometer to ensure that the transmittance of the film layer reaches at least 90%.

[0040] S45. Perform film quality inspection, use an optical film thickness gauge to check the uniformity of film thickness, use an electron microscope to check the surface quality of film, and determine whether the deposition quality of the thermal management layer meets the design requirements.

[0041] Optionally, step S5 specifically includes:

[0042] Step S51: Clean the surface of the thermal management layer with a mixed solution of deionized water and isopropanol for 5 minutes. After cleaning, blow the substrate dry with nitrogen to ensure that there is no moisture residue on the surface.

[0043] Step S52: Transfer the cleaned optical substrate to the vacuum evaporation equipment and set the initial evaporation process parameters. During the deposition process, use an aluminum or silver target and evaporate using a resistance heating source. Control the evaporation power to 120W and set the system operating pressure to 2×10⁻⁶. -6 Torr;

[0044] In step S53, during the deposition of the reflective layer, the deposition rate is set to 1.5 nm per minute, and the final thickness of the film is controlled between 100 nm and 200 nm. A directional evaporation source is used, and the distance between the evaporation source and the substrate is adjusted to control the evaporation angle and flow direction, so as to ensure the uniformity of the film.

[0045] Optionally, after step S53, the method further includes:

[0046] Step S54: After deposition, the reflectivity of the reflective layer is tested using a UV-Vis spectrophotometer to determine whether the reflective layer can provide near total reflection within the required wavelength range. The optical performance of the reflective layer is evaluated through transmittance and reflectivity tests.

[0047] Step S55: Use standard reflectance testing equipment to comprehensively measure the reflectance of the reflective layer, determine whether the reflectance has reached the expected design value, and conduct a full-spectrum reflectance test.

[0048] The present invention also provides a multilayer optical film, which is prepared by the multilayer optical film preparation method described above, wherein the multilayer optical film specifically comprises:

[0049] Optical glass substrate;

[0050] An anti-reflective layer with anti-reflective properties is deposited on the optical glass substrate;

[0051] A high damage threshold protective layer deposited on the antireflective layer is made of silicon nitride or aluminum nitride.

[0052] The thermal management layer deposited on the high damage threshold protective layer is made of metal oxide or nitride material;

[0053] The reflective layer, deposited on the thermal management layer, is made of aluminum or silver metal and provides total reflection.

[0054] The present invention also provides an imaging device comprising, as described above, a multilayer optical film.

[0055] Compared with existing technologies, this invention has the following advantages: First, an optical glass substrate is provided, and an anti-reflection layer is deposited using reactive magnetron sputtering technology to achieve high transparency. A beam-splitting design algorithm is used to pattern the anti-reflection layer and transfer it to the film layer, optimizing optical performance by forming a multilayer film structure. Then, a high damage threshold protective layer is deposited to improve the film layer's resistance to laser damage. Next, a thermal management layer is deposited to improve the film layer's thermal stability. Finally, a reflective layer is deposited via evaporation to form a multilayer film structure, providing total internal reflection and enhancing the laser display effect. After all layers are completed, annealing is performed to improve the bonding force between the film layers, thereby improving the overall performance and stability of the film layer. This method, through optimized design of the overall fabrication process, takes into account both laser damage resistance and thermal stability, while the thermal management layer provides thermal stability and the reflective layer improves the efficiency of the optical system, thus producing a high-performance, multifunctional multilayer optical film that meets the high requirements of laser display systems. Attached Figure Description

[0056] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0057] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0058] Figure 1 This is one of the flowcharts illustrating the preparation method of the multilayer optical film in this embodiment.

[0059] Figure 2 This is the second schematic diagram of the process for preparing the multilayer optical film in this embodiment.

[0060] Figure 3 This is the third schematic diagram of the process for preparing the multilayer optical film in this embodiment. Detailed Implementation

[0061] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0062] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0063] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0064] Example 1:

[0065] Combination Figures 1 to 3 As shown, an embodiment of the present invention provides a method for preparing a multilayer optical film, comprising:

[0066] Step S1: Provide an optical glass substrate and deposit an anti-reflective layer on the optical glass substrate using reactive magnetron sputtering technology. The anti-reflective layer is made of magnesium fluoride or silicon dioxide material. Preferably, rare earth elements can be added to optimize optical performance and form an anti-reflective layer with high transparency.

[0067] Step S2 involves using a beam-splitting design algorithm to pattern the anti-reflective layer and transferring the designed beam-splitting pattern onto the anti-reflective layer; wavelength selectivity is adjusted through the multilayer structure of the interference film. The designed beam-splitting pattern optimizes light transmittance, reduces reflection, and meets the requirements of ultra-short focal length characteristics, achieving high-efficiency optical performance.

[0068] Step S3: Deposit a high damage threshold protective layer on the anti-reflective layer. The high damage threshold protective layer is made of silicon nitride or aluminum nitride material to improve the damage resistance and thermal stability of the film and ensure the long-term stability of the film under strong light.

[0069] Step S4: Deposit a thermal management layer on the high damage threshold protective layer. The thermal management layer uses metal oxides or nitrides with high thermal conductivity to improve the thermal stability of the film. This improves the thermal stability and light resistance of the film, reduces the interference of ambient light on the display effect, and enhances color saturation.

[0070] Step S5: A reflective layer is deposited on the thermal management layer by evaporation to form a multilayer film structure. The reflective layer is made of a metallic material such as aluminum or silver to provide total reflection and help guide or recover the laser beam.

[0071] Step S6: Anneal the formed multilayer film structure and set the annealing condition to a preset temperature to improve the interfacial bonding force between the multilayer film structures and obtain a multilayer optical film.

[0072] The working principle of this invention is as follows: First, an optical glass substrate is provided, and an anti-reflection layer is deposited using reactive magnetron sputtering technology to achieve high transparency. A beam-splitting design algorithm is then used to pattern the anti-reflection layer and transfer it to the film layer. This forms a multilayer film structure to optimize optical performance. Next, a high damage threshold protective layer is deposited to improve the film layer's resistance to laser damage. Then, a thermal management layer is deposited to enhance the film layer's thermal stability. Finally, a reflective layer is deposited via evaporation to form a multilayer film structure, providing total internal reflection and enhancing the laser display effect. After all layers are completed, annealing is performed to improve the bonding strength between the film layers, thereby improving the overall performance and stability of the film layer. This method, through optimized design of the overall fabrication process, takes into account both laser damage resistance and thermal stability provided by the thermal management layer, and the efficiency of the reflective layer to improve the optical system, thus producing a high-performance, multifunctional multilayer optical film that meets the high requirements of laser display systems.

[0073] In this embodiment, the specific process for preparing the optical glass substrate is as follows:

[0074] Step S101: Determine the required optical glass composition according to the design requirements and select suitable raw materials for manufacturing optical glass.

[0075] Step S102: Mix the selected raw materials according to a preset ratio and melt them into glass liquid under high temperature conditions, typically 1500°C to 2000°C.

[0076] Step S103: The molten glass liquid is formed into an optical glass substrate with a preset shape through a mold; the forming method can be selected as needed, such as float glass, wire drawing or rolling.

[0077] Step S104: The optical glass substrate is surface-treated by chemical polishing, and then the substrate surface is cleaned by ultrasonic cleaning to remove surface contaminants.

[0078] Process: Deionized water, acetone or ethanol are commonly used for cleaning, followed by drying in a nitrogen stream.

[0079] In this embodiment, step S1 specifically includes:

[0080] Step S11: Secure the clean, transparent glass substrate into the deposition chamber and perform a pre-inspection of the reactive magnetron sputtering equipment.

[0081] Step S12: Place the cleaned optical glass substrate in a reactive magnetron sputtering device to begin surface pretreatment. Specifically, use low-energy argon plasma to treat the substrate surface to remove residual contaminants and activate the substrate surface. The power during the treatment is 100W, the argon flow rate is set to 20sccm, and the treatment time is 3 minutes.

[0082] Step S13: In the reactive magnetron sputtering process, magnesium fluoride or silicon dioxide is selected as the anti-reflection layer material, oxygen is used as the reactive gas, and the thickness of the film is controlled by adjusting the sputtering power, gas flow rate and working pressure to perform reactive magnetron sputtering deposition; the sputtering power is set to 200W, the oxygen flow rate is 5sccm, and the working pressure is maintained at a low pressure of 0.3Pa.

[0083] Step S14: During reactive magnetron sputtering, the distance between the magnesium fluoride or silicon dioxide target and the optical glass substrate is adjusted to optimize the deposition uniformity of the thin film; this distance is controlled within 50 mm to ensure good coverage and optical performance of the film. The deposition rate is controlled at 1.5 nm per minute to ensure uniform thickness and high transparency of the antireflective layer.

[0084] Step S15: After the deposition process is completed, the film thickness is measured in real time using an optical film thickness gauge, and the transmittance of the film is tested using a UV-Vis spectrophotometer to ensure that the film transmittance reaches more than 90%.

[0085] Ensure the thickness of the anti-reflective layer is precisely controlled between 30 and 50 nm. This thickness range effectively reduces light reflection while ensuring a highly transparent anti-reflective effect.

[0086] Finally, the deposited antireflective layer is heat-treated to eliminate any internal stress that may have occurred during the film deposition process, further improving the film's transparency and stability. The heat treatment temperature is set at 150°C, and the treatment time is 30 minutes.

[0087] In this embodiment, step S2 specifically includes:

[0088] Step S21: Use optical design software (such as TFCalc or FilmStar) to model the optical performance of the anti-reflection layer. Use a beam splitting film design algorithm to ensure that the designed beam splitting pattern can effectively improve light transmittance and reduce reflection. Select the corresponding material refractive index and film thickness to meet the preset wavelength range requirements.

[0089] Step S22: In the process of designing the spectral pattern, by adjusting the thickness distribution, number of layers and optical path difference of the film, the designed anti-reflection pattern can generate multiple interferences within the required spectral range, thereby achieving a wide-band or narrow-band anti-reflection effect; specifically, the design wavelength range can be set between 400 nm and 700 nm to meet the requirements of the visible spectrum.

[0090] S23. After the beam splitting pattern design is completed, a digital pattern file is generated and converted into a photolithography template. The designed beam splitting pattern is transferred to the anti-reflection layer on the optical glass substrate using patterned exposure technology (such as electron beam exposure or laser exposure). This step ensures high-precision transfer of the pattern and stability of optical performance.

[0091] S24. A scanning electron microscope is used to examine the pattern structure after the pattern transfer, to detect whether there is any distortion or error in the pattern structure, and to correct it by adjusting the exposure intensity or exposure time based on the deviation results.

[0092] S25. After the pattern transfer is completed, reactive ion etching technology is used to select an etching gas for dry etching to remove unwanted film layers and retain the designed spectroscopic pattern. The power during the etching process is set to 150W, the gas flow rate is 15sccm, and the working pressure is controlled at 1Pa.

[0093] After etching, a cleaning step is performed using a combination of deionized water and ultrasonic cleaning to thoroughly remove any remaining etching residue from the substrate. Subsequently, nitrogen gas is used for drying to ensure the pattern is clear and free of contaminants, and to prevent any impact on subsequent film deposition.

[0094] In this embodiment, step S3 specifically includes:

[0095] Step S31: Ultrasonic cleaning is performed using a mixture of deionized water and isopropanol for 5 minutes to remove residual impurities from the optical substrate surface and perform surface cleaning treatment.

[0096] Step S32: The cleaned optical substrate is transferred to a reactive magnetron sputtering apparatus for deposition, and the process is run according to the initial sputtering parameters set. Specifically, silicon nitride or aluminum nitride is selected as the target material, and nitrogen gas is added as the reactive gas during the deposition process. The sputtering power is set to 300W, the nitrogen flow rate is 10sccm, and the working pressure is maintained at 0.4Pa to ensure that the deposited film has high density and uniformity.

[0097] During deposition, the deposition rate of silicon nitride or aluminum nitride is controlled to ensure uniform film thickness. The deposition rate is set to 2 nm per minute to ensure sufficient film thickness and a high damage threshold. Based on design requirements, the final film thickness is controlled between 50 nm and 100 nm to guarantee its protective effect under high-energy environments such as laser radiation.

[0098] Step S33: During the deposition process, the gas flow rate and power parameters are dynamically adjusted according to the reactivity and deposition rate of the film to optimize the physical and optical properties of the film. During this process, a real-time monitoring system (such as an optical film thickness gauge) is used to monitor the deposition thickness of the film to ensure that the film thickness is within the specified range.

[0099] Step S34: After deposition, the transmittance of the deposited high-damage-threshold protective layer is tested using a UV-Vis spectrophotometer to ensure that the film layer has good transmittance performance in the required wavelength range and also possesses a high damage threshold. Furthermore, the film surface is inspected using a scanning electron microscope (SEM) to ensure the uniformity and density of the film layer, ensuring that it can effectively protect the underlying anti-reflective layer from the influence of the external environment.

[0100] In this embodiment, step S4 specifically includes:

[0101] Step S41: Transfer the optical substrate to a metal oxide or nitride deposition device with high thermal conductivity to prepare for the deposition of the thermal management layer. The initial deposition settings are as follows: control the sputtering power to be 350W, the oxygen flow rate to be 15sccm, and the working pressure to be 0.3Pa. Select materials such as aluminum, copper, alumina, or aluminum nitride as the deposition material for the thermal management layer to ensure that the film has good thermal conductivity.

[0102] S42, during the deposition process, the film thickness is monitored in real time, the growth rate of the film is tracked by an optical film thickness gauge, and the deposition rate is adjusted to control the thickness of the thermal management layer between 50 and 150 nanometers.

[0103] Based on the characteristics of the material, the deposition rate is set to 2 to 3 nanometers per minute to ensure the uniformity of the film layer, so that the thermal management layer is uniformly covered on the surface of the high damage threshold protective layer.

[0104] S43, during the deposition of the thermal management layer, the nitrogen flow rate is controlled at 10 sccm and the oxygen flow rate at 5 sccm to adjust the composition of the film layer.

[0105] To optimize thermal management performance, the ratio of nitrogen to oxygen was controlled to ensure that the deposited thermal management layer possesses good thermal conductivity and the necessary chemical stability. Through this adjustment, the thermal conductivity of the film layer reached over 100 W / m·K, effectively dispersing and conducting heat.

[0106] S44. After deposition, the transmittance of the thermal layer is tested using a UV-Vis spectrophotometer to ensure that the transmittance of the film layer reaches at least 90% to reduce the impact on the optical properties of the underlying film. At the same time, the surface structure of the film layer is observed using a scanning electron microscope (SEM) to confirm that the film layer is free of defects such as cracks, peeling, or particles.

[0107] S45. Perform film quality inspection, use an optical film thickness gauge to check the uniformity of film thickness, use an electron microscope to check the surface quality of film, and determine whether the deposition quality of the thermal management layer meets the design requirements.

[0108] In this embodiment, step S5 specifically includes:

[0109] Step S51: Clean the surface of the thermal management layer with a mixed solution of deionized water and isopropanol for 5 minutes. After cleaning, blow the substrate dry with nitrogen to ensure that there is no moisture residue on the surface.

[0110] To remove impurities that may affect film deposition, a mixture of deionized water and isopropanol was used for cleaning, followed by ultrasonic cleaning for 5 minutes. After cleaning, the substrate was dried with nitrogen gas to ensure no moisture residue remained on the surface, thus guaranteeing the quality of the reflective layer deposition.

[0111] Step S52: Transfer the cleaned optical substrate to the vacuum evaporation equipment and set the initial evaporation process parameters. During the deposition process, use an aluminum or silver target and evaporate using a resistance heating source. Control the evaporation power to 120W and set the system operating pressure to 2×10⁻⁶. -6 Torr;

[0112] The selected reflective layer material is aluminum or silver, which has good reflective properties and optical stability to ensure high vacuum conditions during the evaporation process, which helps to achieve uniform deposition and high density of the film.

[0113] In step S53, during the deposition of the reflective layer, the deposition rate is set to 1.5 nm per minute, and the final thickness of the film is controlled between 100 nm and 200 nm. A directional evaporation source is used, and the distance between the evaporation source and the substrate is adjusted to control the evaporation angle and flow direction to ensure the uniformity of the film.

[0114] Maintaining an appropriate deposition rate ensures the uniformity and reflectivity of the film. A thickness range of 100 nm to 200 nm ensures that the reflective layer has excellent reflectivity and does not adversely affect the underlying optical film.

[0115] During the deposition process, the evaporation rate of aluminum or silver needs to be precisely controlled to ensure that the reflective layer is uniformly covered on the entire substrate surface and to avoid inconsistent film thickness.

[0116] Step S54: After deposition, the reflectivity of the reflective layer is tested using a UV-Vis spectrophotometer to determine whether the reflective layer can provide near total reflection within the required wavelength range. The optical performance of the reflective layer is evaluated through transmittance and reflectivity tests to ensure that its reflectivity reaches more than 90% and that the optical stability of the reflective layer is good.

[0117] Step S55: Use standard reflectance testing equipment to comprehensively measure the reflectance of the reflective layer, determine if the reflectance meets the expected design value, and conduct a full-spectrum reflectance test; ensure that the reflective layer has good reflectance performance within the required wavelength range. During this process, the film layer exhibits uniform reflectance performance across the entire spectral range.

[0118] Example 2:

[0119] The present invention also provides a multilayer optical film, which is prepared by the method for preparing multilayer optical films as described in Example 1. The multilayer optical film specifically includes:

[0120] Optical glass substrate;

[0121] An anti-reflective layer with anti-reflective properties is deposited on an optical glass substrate;

[0122] A high damage threshold protective layer deposited on the anti-reflective layer is made of silicon nitride or aluminum nitride.

[0123] The thermal management layer deposited on the high damage threshold protective layer is made of metal oxide or nitride materials;

[0124] The reflective layer, deposited on the thermal management layer, is made of aluminum or silver metal and provides total reflection.

[0125] Example 3:

[0126] The present invention also provides an imaging device, including a multilayer optical film as described in Embodiment 2.

[0127] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method of making a multilayer optical film, characterized by, The application relates to an optical film manufacturing method, which comprises the following steps: S1, providing an optical glass substrate, depositing an anti-reflection layer on the optical glass substrate by a reactive magnetron sputtering technology, the anti-reflection layer is made of magnesium fluoride or silicon dioxide material, and the anti-reflection layer with high transparency is formed; S2, using a light splitting film design algorithm to design a pattern of the anti-reflection layer, and transferring the designed light splitting pattern to the anti-reflection layer; S3, depositing a high-damage threshold protection layer on the anti-reflection layer, the high-damage threshold protection layer is made of silicon nitride or aluminum nitride material; S4, depositing a heat management layer on the high-damage threshold protection layer, the heat management layer is made of a metal oxide with high thermal conductivity, and the heat stability of the thin film is improved; S5, depositing a reflection layer on the heat management layer by an evaporation method, forming a multilayer film structure, the reflection layer is made of aluminum or silver, and full reflection is provided; S6, annealing the formed multilayer film structure, and setting an annealing condition as a preset temperature, so as to improve the interface bonding force between the multilayer film structure, and a multilayer optical film is obtained.

2. The method of making a multilayer optical film according to claim 1, wherein, The preparation process of the optical glass substrate is specifically as follows: S101, according to the design requirement, determining the required optical glass composition, and selecting raw materials suitable for manufacturing the optical glass; S102, mixing the selected raw materials according to a preset proportion, and melting into a glass liquid under high-temperature conditions, and the melting temperature is 1500 DEG C to 2000 DEG C; S103, forming the melted glass liquid into an optical glass substrate with a preset shape through a mold; and S104, performing surface treatment on the optical glass substrate by a chemical polishing method, and then cleaning the surface of the substrate by ultrasonic cleaning to remove surface contaminants.

3. The method of making a multilayer optical film according to claim 2, wherein, The step S1 specifically comprises: S11, fixing a clean transparent glass substrate into a deposition chamber, and pre-inspecting a reactive magnetron sputtering equipment; S12, placing the cleaned optical glass substrate into the reactive magnetron sputtering equipment, and starting to perform surface pretreatment, specifically, treating the surface of the substrate by using a low-energy argon plasma to remove surface residual contaminants and activate the surface of the substrate, the power in the treatment process is 100 W, the argon flow rate is set to 20 sccm, and the treatment time is 3 minutes; S13, in the reactive magnetron sputtering process, magnesium fluoride or silicon dioxide is selected as the anti-reflection layer material; if silicon dioxide is selected, oxygen is used as the reaction gas, the thickness of the thin film is controlled by adjusting the sputtering power, the gas flow rate and the working pressure, and the reactive magnetron sputtering deposition is carried out; S14, in the reactive magnetron sputtering process, the distance between the magnesium fluoride or silicon dioxide material target and the optical glass substrate is adjusted to optimize the deposition uniformity of the thin film; S15, after the deposition process is completed, the thickness of the thin film is measured in real time by using an optical film thickness instrument, and the transmittance of the thin film is tested by using an ultraviolet-visible spectrophotometer, so that the transmittance of the thin film is higher than 90%.

4. The method of making a multilayer optical film according to claim 3, wherein, The step S2 specifically comprises: Step S21, the optical performance of the anti-reflection layer is modeled using optical design software, and the designed light splitting pattern is ensured to effectively improve the light transmittance and reduce the reflection by the light splitting film design algorithm, and the corresponding material refractive index and film thickness are selected to meet the preset wavelength range requirements; Step S22, during the design of the light splitting pattern, the thickness distribution, number of layers and optical path difference of the film layer are adjusted to make the designed anti-reflection pattern produce multiple interferences in the required spectral range, thereby realizing the anti-reflection effect of a wide or narrow waveband; S23, after the design of the light splitting pattern is completed, a digital pattern file is generated and converted into a photolithography template, and a patterned exposure technology is used to transfer the designed light splitting pattern to the anti-reflection layer on the optical glass substrate; S24, the pattern structure after pattern transfer is checked using a scanning electron microscope to detect whether the pattern structure has distortion or error, and the exposure intensity or exposure time is adjusted for correction according to the deviation result; S25, after the pattern transfer is completed, a reactive ion etching technology is used to perform dry etching by selecting etching gas to remove unnecessary film layers and retain the designed light splitting pattern, and the power setting during etching is 150W, the gas flow is 15sccm, and the working pressure is controlled at 1Pa.

5. The method of making a multilayer optical film according to claim 1, wherein, The step S3 specifically includes: Step S31, ultrasonic cleaning is performed using a mixture of deionized water and isopropyl alcohol, and the cleaning process lasts for 5 minutes to remove impurities remaining on the surface of the optical substrate for surface cleaning treatment; Step S32, the cleaned optical substrate is transferred to a reactive magnetron sputtering device for deposition process, and the initial sputtering parameters are set to run; Step S33, during the deposition process, the gas flow and power parameters are dynamically adjusted according to the reactivity and deposition rate of the thin film to optimize the physical and optical properties of the film layer; Step S34, after the deposition is completed, the transmittance of the deposited high damage threshold protective layer is tested using a UV-Vis spectrophotometer to ensure that the film layer has good light transmittance performance in the required waveband.

6. The method of making a multilayer optical film according to claim 1, wherein, The step S4 specifically includes: Step S41, the optical substrate is transferred to a metal oxide or nitride deposition device with high thermal conductivity performance to prepare for the deposition of the thermal management layer, and the initial deposition adjustment is set to control the sputtering power to be 350W, the oxygen flow to be 15sccm, and the working pressure to be 0.3Pa; S42, during the deposition process, the film thickness is monitored in real time, the growth rate of the film layer is tracked using an optical film thickness meter, and the deposition rate is adjusted to control the thickness of the thermal management layer to be within the range of 50 to 150 nanometers; S43, during the deposition of the thermal management layer, the nitrogen flow is controlled at 10sccm and the oxygen flow is controlled at 5sccm to adjust the composition of the film layer; S44, after the deposition is completed, the transmittance of the thermal management layer is tested using a UV-Vis spectrophotometer to make the film layer transmittance reach at least 90%; S45, the film layer quality is checked, the thickness uniformity of the film layer is checked using an optical film thickness meter, and the surface quality of the film layer is checked using an electron microscope to determine whether the deposition quality of the thermal management layer meets the design requirements.

7. The method of making a multilayer optical film according to claim 1, wherein, The step S5 specifically includes: Step S51, using a mixed solution of deionized water and isopropyl alcohol to clean the surface of the thermal management layer, the cleaning time is 5 minutes, after cleaning, the substrate is blown dry with nitrogen to ensure that the surface is free of moisture; Step S52, the cleaned optical substrate is transferred to a vacuum evaporation device, and the initial evaporation process parameters are set. During the deposition process, aluminum or silver target material is evaporated by a resistance heating source, the evaporation power is controlled to be 120 W, and the working pressure of the system is set to be 2 x 10 -6 Torr. Step S53, during the deposition of the reflective layer, the deposition rate is set to 1.5 nm per minute, and the final thickness of the film layer is controlled between 100 nm and 200 nm; a directional evaporation source is used to adjust the distance between the evaporation source and the substrate, control the angle and flow direction of evaporation, and ensure the uniformity of the film layer.

8. The method of making a multilayer optical film according to claim 7, wherein, The step S53 further includes: Step S54, after deposition, using a UV-visible spectrophotometer to test the reflectivity of the reflective layer, to determine whether the reflective layer can provide near full reflection effect in the required waveband, and to evaluate the optical performance of the reflective layer through transmittance and reflectivity tests; Step S55, using standard reflection test equipment to comprehensively measure the reflectivity of the reflective layer, to determine whether the reflectivity reaches the expected design value, and to perform full-spectrum reflectivity test.

9. A multilayer optical film characterized by, The multilayer optical film is prepared by the method of any one of claims 1 to 8, and specifically includes: An optical glass substrate; An antireflection layer having an antireflection effect, deposited on the optical glass substrate; A high damage threshold protection layer deposited on the antireflection layer, using silicon nitride or aluminum nitride material; A thermal management layer deposited on the high damage threshold protection layer, using metal oxide or nitride material; A reflective layer deposited on the thermal management layer, using aluminum or silver, providing full reflection effect.

10. An image forming apparatus characterized by comprising: The multilayer optical film of claim 9.

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