An ultrathin low-reflection film filter based on super-multilayer vacuum coating technology and a coating process thereof

Abstract

The application provides an ultrathin low-reflection film filter based on a multilayer vacuum plating technology and a plating process thereof, comprising a substrate Sub and an ultrathin low-reflection film structure arranged on the surface of the substrate, wherein the ultrathin low-reflection film structure comprises the following film layers in sequence: 1H, 2M, 3H, 4M, 5H, 6M, 7H, 8M, 9H, 10M, 11H and 12L; the film layer thickness is accurately controlled to realize low reflection in a 420nm-680nm wave band, the maximum reflectivity Rmax is less than or equal to 0.1%, and the maximum transmissivity T is about 99.9% high transmissivity; the application solves the ghost phenomenon of stray light and glare caused by high reflectivity in the 420nm-680nm wave band; a magnesium fluoride film layer with a refractive index lower than that of titanium pentoxide is added between the film layer and the incident medium air to optimize the film layer, so that the admittance values of the film layer and the substrate and the film layer and the incident medium are matched; the added layer is equivalent to a reflection-reducing film at the boundary of the multilayer film; and finally, the ultralow reflection in the wave band is realized, and the purpose of close-to-zero reflection is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical film technology, in particular to an ultrathin low-reflection film filter based on super-multilayer vacuum coating technology and a coating process thereof. BACKGROUND

[0002] As is well known in the optical art, reflection of light from glass and other surfaces is undesirable, or produces visual discomfort. In addition to this undesirable effect, reflected light can cause dizziness or a blurred image to the user. For optical lenses of particular interest, coatings and methods have been developed to reduce reflection from the surface of the optical lens. In order to ensure that the residual reflection remains at a relatively small value over the entire visible spectrum, a considerable number of anti-reflective (AR) coatings have been proposed in the prior art. Single or double layer coatings have given significant improvements, but the residual reflection is still greater than desired. In order to improve the properties of the AR, the prior art has resorted to AR coatings having three or more layers.

[0003] Surface microstructure + nano-imprinting technology, derived from photonic crystal technology, makes a photonic crystal template, uses nano-imprinting technology, transfers to the film, and then pastes on the surface of the optoelectronic component. There may be multi-stage diffraction and poor wear resistance. Inclined porous coating, large-angle evaporation of porous film, can prepare the lowest 1.05 low refractive index, which inevitably brings the wavelength shift. ALD deposition technology, accurate control, can prepare better ultrathin low-reflection film and excellent uniformity, which may bring greater scattering, uncontrollable wear resistance, and low production efficiency at present. Super-multilayer vacuum coating, easy to design, combined with ion source assistance, excellent physical and optical properties.

[0004] The conventional product on the market has a reflectivity Rmax≤0.5. For high-order optical lenses, light energy loss, glare, and ghosting of stray light may occur during use. Therefore, an ultralow-reflection filter with a reflectivity Rmax≤0.1 in the wavelength range of 420nm-680nm is needed. SUMMARY

[0005] The present application aims to provide an ultrathin low-reflection film filter based on super-multilayer vacuum coating technology and a coating process thereof, to solve the problems raised in the background art.

[0006] In order to solve the above technical problems, the present application provides the following technical solutions: a substrate Sub and a single-sided ultra-thin low-reflection film structure arranged on the surface of the substrate, the substrate material is blue glass or white glass, the ultra-thin low-reflection film structure sequentially comprises the following film layers: 1H, 2M, 3H, 4M, 5H, 6M, 7H, 8M, 9H, 10M, 11H, and 12L, wherein the numbers represent the film layer sequence, H, M, and L represent the refractive index of the film layer, H represents that the film layer uses high refractive index material, M represents that the film layer uses medium refractive index material, and L represents that the film layer uses low refractive index material, the high refractive index material, the medium refractive index material, and the low refractive index material are titanium pentoxide, silicon dioxide, and magnesium fluoride respectively, the optical thickness of each film layer is λ0 / 4, and the physical thickness unit is nm,

[0007] The optical thickness of the 1H layer is 0.167, and the physical thickness is 9.43;

[0008] The optical thickness of the 2M layer is 0.575, and the physical thickness is 53.96;

[0009] The optical thickness of the 3H layer is 0.444, and the physical thickness is 25.04;

[0010] The optical thickness of the 4M layer is 0.538, and the physical thickness is 50.51;

[0011] The optical thickness of the 5H layer is 0.382, and the physical thickness is 21.52;

[0012] The optical thickness of the 6M layer is 0.852, and the physical thickness is 80.00;

[0013] The optical thickness of the 7H layer is 0.322, and the physical thickness is 18.14;

[0014] The optical thickness of the 8M layer is 0.445, and the physical thickness is 41.79;

[0015] The optical thickness of the 9H layer is 1.312, and the physical thickness is 73.92;

[0016] The optical thickness of the 10M layer is 0.095, and the physical thickness is 8.92;

[0017] The optical thickness of the 11H layer is 0.534, and the physical thickness is 30.08;

[0018] The optical thickness of the 12L layer is 0.98, and the physical thickness is 97.34.

[0019] The refractive index of the substrate Sub is 1.52.

[0020] Through the above scheme, the optical thickness and the physical thickness of the film layer are the design thickness, the film system structure of the short-wave pass filter film is Sub / (0.5LH0.5L)^11, the plating film substrate Sub is k9 glass, the trititanium pentoxide film layer is H, and the silicon dioxide film layer is L, so that the equivalent refractive index of the film layer in the passband is close to the substrate refractive index, the long-wave transmission passband area wave is compressed, and the 420nm-680nm waveband antireflection effect is realized, that is, the low reflection of the 420nm-680nm waveband is realized, the maximum reflectivity Rmax is less than or equal to 0.1%, and the maximum transmittance T is about 99.9% high transmittance. The present application solves the "ghost" phenomenon of stray light and glare caused by high reflectivity in the 420nm-680nm waveband, the film layer and the incident medium air are added with a magnesium fluoride film layer having a lower refractive index than the trititanium pentoxide, the film layer is optimized, the admittance values of the film layer and the substrate and the film layer and the incident medium are matched, the added layer is equivalent to a multilayer film boundary antireflection film, and finally the wide waveband ultralow reflection close to zero reflection is realized.

[0021] An ultrathin low-reflection film filter plating process based on a multilayer vacuum plating technology, characterized by comprising the following steps:

[0022] S1: trititanium pentoxide film material, silicon dioxide and magnesium fluoride film material are loaded into a plating machine cavity;

[0023] S2: after the plating film substrate is cleaned and water is removed, the substrate is placed into the plating machine, the plating machine is vacuumized and heated to 200 DEG C, then constant temperature baking is performed for 30 min, when the vacuum degree in the plating machine is 6.0-4 Pa, ion source cleaning is started for 10 min, the ion source anode voltage is 180 V, the anode current is 5 A, and the high-purity argon gas flow is 5 SCCM;

[0024] S3: an electron beam and ion source bombardment vacuum plating process is used to sequentially plate 1H, 2M, 3H, 4M, 5H, 6M, 7H, 8M, 9H, 10M, 11H and 12L film layers on the first surface of the substrate, the optical thickness is monitored in real time, the physical thickness is monitored according to the optical thickness monitoring result, a stop signal is sent when the set thickness is reached, the equipment is switched to an evaporation source, and the next film layer is plated. When the silicon dioxide film layer is plated, the temperature is 200 DEG C, the vacuum degree is 2.3-2 Pa, an 8KV high voltage is used, an electron beam is formed by using a magnetic field focusing, the silicon dioxide film material is bombarded, the silicon dioxide film material is evaporated, the evaporation rate is 0.5-1 A / s, and the deposition rate is 0.5-1 A / s. At the same time, ion beam assisted deposition is performed by starting the ion source bombardment, the ion source anode voltage is 130 V, the anode current is 3 A, the high-purity argon gas flow is 8 SCCM, and the high-purity oxygen gas flow is 20 SCCM.

[0025] The temperature of the silicon dioxide film layer is 200 DEG C, the vacuum degree is 2.3-2Pa, 8KV high voltage is used, electron beam is formed by magnetic field focusing, the silicon dioxide film material is bombarded to evaporate the silicon dioxide film material, the evaporation rate is 0.5-1.5A Meanwhile, ion source bombardment is started to perform ion beam assisted deposition, the anode voltage of the ion source is 500V, the anode current is 500mA, the flow of high-purity argon is 8SCCM, and the flow of high-purity oxygen is 20SCCM.

[0026] The temperature of the titanium pentoxide film layer is 200 DEG C, the vacuum degree is 2.3-2Pa, 8KV high voltage is used, electron beam is formed by magnetic field focusing, the titanium pentoxide film material is bombarded to evaporate the titanium pentoxide film material, the evaporation rate is 0.5-1.5A Meanwhile, ion source bombardment is started to perform ion beam assisted deposition, the anode voltage of the ion source is 130V, the anode current is 3A, the flow of high-purity argon is 8SCCM, and the flow of high-purity oxygen is 20SCCM.

[0027] The temperature of the magnesium fluoride film layer is 300 DEG C, 8KV high voltage is used, electron beam is formed by magnetic field focusing, the magnesium fluoride film material is bombarded to evaporate the magnesium fluoride film material, the evaporation rate is 0.5-1.5A

[0028] The coating machine comprises a direct light control system, the direct light control system comprises a light source system, a light receiving system, an acquisition system and a control system, the light source system comprises a bulb, a bulb box, a bulb seat and a bulb power supply, the bulb is fixed in the bulb seat, the bulb power supply outputs voltage, the bulb emits 360-2500nm wave band light after being electrified, the light receiving system comprises an adapter plate, a collimating mirror and an optical fiber, the collimating mirror is fixed outside the coating machine through the adapter plate, one end of the optical fiber is vertically fixed on the collimating mirror, the collimating mirror is provided with an XYZ axis moving device, the acquisition system comprises a monochromator, a photodiode, a signal amplifier and an acquisition module.

[0029] Through the above scheme, based on the interference effect of light, in the coating process, the thickness of the film continuously changes, and its transmittance also continuously changes, when the film thickness reaches the control wavelength λ / 4 or its integer multiple, the reflected light or transmitted light will reach the maximum (minimum) value, by monitoring the maximum (minimum) value as a scale, directly measuring and controlling the optical thickness of the film layer on the surface of the part, the optical fiber is connected with the optical fiber receiving head and the monitoring product, the light emitted by the bulb is on the same normal line, to ensure that the received light intensity is maximum, the received light is input into the monochromator through the optical fiber, the monochromator sets the monitoring wavelength according to the software, and the single-wavelength light of the set wavelength is output through chopping, the output light passes through the photodiode, and the light intensity signal is converted into extremely weak electric signal, the electric signal is input into the signal amplifier through the signal line, and the linearly amplified electric signal can be collected into the acquisition module for A / D conversion, analog current signal is converted into digital signal, and is transmitted to the host computer through USB protocol, the control system comprises a matching software algorithm, the software algorithm calculates the transmittance (%) of the monitoring product in real time according to the measured light intensity signal and records it, the optical thickness of the monitoring product at this time is calculated according to the change of the transmittance (mainly according to the maximum / minimum value), and compared with the set thickness, when the set thickness is reached, a stop signal is sent, the equipment is closed, the evaporation source is stopped, and the film layer accumulation is stopped, thereby controlling the optical thickness of the film layer on the surface of the part, the control precision of the film layer is high, and the yield of the film layer can be greatly improved.

[0030] Compared with the prior art, the beneficial effects achieved by the present application are:

[0031] 1. In the 420nm-680nm waveband, the reflectivity Rmax≤0.1, reaching the optical parameters of ultra-low reflection, which can effectively control the "ghost" phenomenon of astigmatism and glare, and the magnesium fluoride film layer is further optimized to achieve the effect of nearly zero reflection, which can meet the demand of high-order optical modules on the market.

[0032] 2. The optical control system directly monitors the optical thickness to control the physical thickness, and the static signal accuracy is ±0.02%. The optical control system realizes the compensation function and the stop point correction function through the software algorithm, further controls the coating precision, monitors and corrects the whole coating process, ensures the quality of the finished filter, greatly improves the yield, and is suitable for industrial large-scale production.

[0033] 3. The film layer structure only has 12 layers, the number of the whole film layers is low, the coating time is less, and the optical parameters are excellent, and the film layer also has good energy saving and emission reduction effect. DETAILED DESCRIPTION

[0034] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, and do not constitute a limitation of the present application. In the drawings:

[0035] Figure 1 is a schematic diagram of a base surface broadband anti-reflection film;

[0036] Figure 2 is a schematic diagram of a design parameter reflectivity;

[0037] Figure 3 is a schematic diagram of a design parameter luminous flux change;

[0038] Figure 4 is a schematic diagram of a design parameter luminous flux change;

[0039] Figure 5 is a schematic diagram of a design parameter luminous flux change;

[0040] Figure 6 is a schematic diagram of a light control system structure. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0042] The present application provides a technical solution: including a substrate Sub and a single-sided ultra-thin low-reflection film structure arranged on the surface of the substrate, the substrate material is blue glass or white glass, the ultra-thin low-reflection film structure includes the following film layers in order: 1H, 2M, 3H, 4M, 5H, 6M, 7H, 8M, 9H, 10M, 11H, 12L, wherein the numbers represent the order of the film layers, H, M, L represent the refractive index of the film layer, H represents that the film layer uses high refractive index material, M represents that the film layer uses medium refractive index material, and L represents that the film layer uses low refractive index material, the high refractive index, medium refractive index and low refractive index materials are titanium pentoxide, silicon dioxide and magnesium fluoride respectively, the optical thickness of each film layer is λ0 / 4, and the physical thickness unit is nm,

[0043] 1H layer optical thickness is 0.167, physical thickness is 9.43;

[0044] 2M layer optical thickness is 0.575, physical thickness is 53.96;

[0045] 3H layer optical thickness is 0.444, physical thickness is 25.04;

[0046] 4M layer optical thickness is 0.538, physical thickness is 50.51;

[0047] 5H layer optical thickness is 0.382, physical thickness is 21.52;

[0048] 6M layer optical thickness is 0.852, physical thickness is 80.00;

[0049] 7H layer optical thickness is 0.322, physical thickness is 18.14;

[0050] 8M layer optical thickness is 0.445, physical thickness is 41.79;

[0051] 9H layer optical thickness is 1.312, physical thickness is 73.92;

[0052] 10M layer optical thickness is 0.095, physical thickness is 8.92;

[0053] 11H layer optical thickness is 0.534, physical thickness is 30.08;

[0054] 12L layer optical thickness is 0.98, physical thickness is 97.34.

[0055] The refractive index of the substrate Sub is 1.52.

[0056] The plating process comprises the following steps:

[0057] S1: Put the titanium pentoxide film material, silicon dioxide and magnesium fluoride film material into the cavity of the film plating machine;

[0058] S2: After the film plating substrate is washed and dehydrated, it is placed in the film plating machine. The film plating machine is vacuumed and heated to 200℃, then constant temperature baking for 30min. When the vacuum degree in the film plating machine is 6.0-4Pa, start the ion source cleaning for 10min, the anode voltage of the ion source is 180V, the anode current is 5A, and the high-purity argon gas flow is 5SCCM;

[0059] S3: The first surface of the substrate is sequentially plated with 1H, 2M, 3H, 4M, 5H, 6M, 7H, 8M, 9H, 10M, 11H and 12L film layers by using electron beam and ion source bombardment vacuum film plating process. Real-time monitoring of optical thickness, according to the monitoring results of optical thickness, monitoring the physical thickness, when reaching the set thickness, sending stop signal, equipment switching evaporation source, plating the next film layer. When plating the silicon dioxide film layer, the temperature is 200℃, the vacuum degree is 2.3-2Pa, 8KV high voltage is used, electron beam is formed by magnetic field focusing, silicon dioxide film material is evaporated by bombarding silicon dioxide film material, the evaporation rate At the same time, ion beam assisted deposition is carried out by starting the ion source bombardment, the anode voltage of the ion source is 130V, the anode current is 3A, the high-purity argon gas flow is 8SCCM, and the high-purity oxygen gas flow is 20SCCM.

[0060] The temperature is 200 DEG C, the vacuum degree is 2.3-2 Pa, 8KV high voltage is used, the electron beam is formed by magnetic focusing, the silicon dioxide film material is bombarded, the silicon dioxide film material is evaporated, the evaporation rate is 0.5-1.5 A / s The ion source bombardment is started at the same time for ion beam assisted deposition, the anode voltage of the ion source is 500V, the anode current is 500mA, the high-purity argon gas flow is 8SCCM, and the high-purity oxygen gas flow is 20SCCM.

[0061] The temperature is 200 DEG C, the vacuum degree is 2.3-2 Pa, 8KV high voltage is used, the electron beam is formed by magnetic focusing, the silicon dioxide film material is bombarded, the silicon dioxide film material is evaporated, the evaporation rate is 0.5-1.5 A / s The ion source bombardment is started at the same time for ion beam assisted deposition, the anode voltage of the ion source is 500V, the anode current is 500mA, the high-purity argon gas flow is 8SCCM, and the high-purity oxygen gas flow is 20SCCM.

[0062] The temperature is 200 DEG C, the vacuum degree is 2.3-2 Pa, 8KV high voltage is used, the electron beam is formed by magnetic focusing, the silicon dioxide film material is bombarded, the silicon dioxide film material is evaporated, the evaporation rate is 0.5-1.5 A / s

[0063] The coating machine comprises a direct light control system, the direct light control system comprises a light source system, a light receiving system, an acquisition system and a control system, the light source system comprises a bulb, a bulb box, a bulb seat and a bulb power supply, the bulb is fixed in the bulb seat, the bulb power supply outputs voltage, the bulb emits 360-2500nm wave band light after being electrified, the light receiving system comprises an adapter plate, a collimating mirror and an optical fiber, the collimating mirror is fixed outside the coating machine through the adapter plate, one end of the optical fiber is vertically fixed on the collimating mirror, the collimating mirror is provided with an XYZ axis moving device, the acquisition system comprises a monochromator, a photodiode, a signal amplifier and an acquisition module.

[0064] The filter is coated by using the Pelletron Aluga1550 type coating machine to set the design parameters, the coating data is recorded after coating, and the reflectivity of the filter in examples 1-10 is detected by using the Agilent Cary7000 spectrometer, the wavelength unit is nm in the following table, the reflectivity unit is %, and the detection results are as follows:

[0065] Examples 1-5

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073] Examples 6-10

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081]

[0082] According to the example table and Figure 4 Figure 5 It can be seen that the low reflection in the 420-680 nm band is less than 0.1%, and the maximum reflectivity is very low, which can meet the requirements of most high-order optical modules on the market. The most optimal effects are examples 4 and 5, which can achieve a maximum reflectivity of less than 0.1% in the 411-688 nm band.

[0083] It should be noted that, in this document, the terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment.

[0084] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent ones. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An ultrathin low-reflection film filter based on multilayer vacuum coating technology, characterized in that: The structure includes a substrate (Sub) and an ultrathin low-reflection film structure disposed on one side of the substrate surface. The substrate material is blue glass or white glass. The ultrathin low-reflection film structure comprises the following film layers in sequence: 1H, 2M, 3H, 4M, 5H, 6M, 7H, 8M, 9H, 10M, 11H, 12L, where the numbers represent the order of the film layers, H, M, and L represent the refractive indices of the film layers. H indicates that the film layer uses a high refractive index material, M indicates that it uses a medium refractive index material, and L indicates that it uses a low refractive index material. The high refractive index, medium refractive index, and low refractive index materials are titanium pentoxide, silicon dioxide, and magnesium fluoride, respectively. The optical thickness of each film layer is λ0 / 4, and the physical thickness is measured in nm. The optical thickness of layer 1H is 0.167 mm, and the physical thickness is 9.43 mm. The optical thickness of the 2M layer is 0.575, and the physical thickness is 53.

96. The optical thickness of the 3H layer is 0.444 mm, and the physical thickness is 25.04 mm. The optical thickness of the 4M layer is 0.538, and the physical thickness is 50.

51. The optical thickness of layer 5H is 0.382 mm, and the physical thickness is 21.52 mm. The optical thickness of the 6M layer is 0.852, and the physical thickness is 80.

00. The optical thickness of layer 7H is 0.322 mm, and the physical thickness is 18.14 mm. The optical thickness of the 8M layer is 0.445, and the physical thickness is 41.

79. The optical thickness of layer 9H is 1.312 mm, and the physical thickness is 73.92 mm. The optical thickness of the 10M layer is 0.095, and the physical thickness is 8.

92. The optical thickness of layer 11H is 0.534 mm, and the physical thickness is 30.08 mm. The optical thickness of the 12L layer is 0.98, and the physical thickness is 97.

34.

2. The ultrathin low-reflection film filter based on multilayer vacuum coating technology according to claim 1, characterized in that: The refractive index of the substrate Sub is 1.

52.

3. A process for fabricating an ultrathin low-reflection film filter based on multilayer vacuum coating technology according to any one of claims 1-2, characterized in that: Includes the following steps: S1: Load the titanium pentoxide film, silicon dioxide and magnesium fluoride film into the coating machine cavity; S2: After the substrate is cleaned and dehydrated, it is placed in the coating machine. The coating machine is evacuated and heated to 200℃, and then baked at a constant temperature for 30 minutes. When the vacuum degree in the coating machine is 6.0-4Pa, the ion source is started for cleaning for 10 minutes. The ion source has an anode voltage of 180V, an anode current of 5A, and a high-purity argon gas flow rate of 5SCCM. S3: Using electron beam and ion source bombardment vacuum coating process, 1H, 2M, 3H, 4M, 5H, 6M, 7H, 8M, 9H, 10M, 11H and 12L film layers are sequentially deposited on the first surface of the substrate. The optical thickness is monitored in real time, and the physical thickness is monitored based on the optical thickness monitoring results. When the set thickness is reached, a stop signal is issued, the equipment switches the evaporation source, and the next film layer is deposited.

4. The process for fabricating an ultrathin low-reflection film filter based on multilayer vacuum coating technology according to claim 3, characterized in that: During the deposition of the silica film, the temperature is 200℃, the vacuum degree is 2.3-2Pa, an 8KV high voltage is used, and an electron beam is formed by focusing with a magnetic field to bombard the silica film material, causing the silica film material to evaporate at an evaporation rate of 5Å / second. At the same time, an ion source is turned on to bombard the film for ion beam-assisted deposition. The ion source anode voltage is 500V, the anode current is 500mA, the high-purity argon gas flow rate is 8SCCM, and the high-purity oxygen gas flow rate is 20SCCM.

5. The process for fabricating an ultrathin low-reflection film filter based on multilayer vacuum coating technology according to claim 3, characterized in that: During the deposition of the titanium pentoxide film, the temperature is 200℃, the vacuum degree is 2.3-2Pa, an 8KV high voltage is used, and an electron beam is formed by focusing the magnetic field to bombard the titanium pentoxide film material, causing the titanium pentoxide film material to evaporate at a rate of 2Å / second. At the same time, an ion source is turned on to perform ion beam-assisted deposition. The ion source anode voltage is 130V, the anode current is 3A, the high-purity argon gas flow rate is 8SCCM, and the high-purity oxygen gas flow rate is 20SCCM.

6. The process for fabricating an ultrathin low-reflection film filter based on multilayer vacuum coating technology according to claim 3, characterized in that: During the deposition of the magnesium fluoride film, the temperature is 300℃, an 8KV high voltage is used, and an electron beam is formed by focusing the magnetic field to bombard the magnesium fluoride film material, causing the magnesium fluoride film material to evaporate at an evaporation rate of 4Å / second.

7. The process for fabricating an ultrathin low-reflection film filter based on multilayer vacuum coating technology according to claims 3-6, characterized in that, The coating machine includes a direct light control system, which comprises a light source system, a light receiving system, a light acquisition system, and a control system. The light source system includes a bulb, a bulb housing, a bulb socket, and a bulb power supply. The bulb is installed and fixed inside the bulb socket. The bulb power supply outputs voltage, and the bulb emits light in the 360-2500nm wavelength range after being powered on. The light receiving system includes an adapter plate, a collimating lens, and an optical fiber. The collimating lens is fixed to the outside of the coating machine via the adapter plate. One end of the optical fiber is vertically fixed to the collimating lens. The collimating lens is equipped with an XYZ axis moving device. The light acquisition system includes a monochromator, a photodiode, a signal amplifier, and a acquisition module.

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