Preparation method of 8-12μm DLC plus-minus-reflection anti-reflection film on germanium lens substrate

Abstract

A preparation method for coating 8‑12 μm DLC with anti-reflection and anti-reflection film on a germanium lens substrate comprises the following steps: S1, cleaning the surface of the accompanying coating sheet and the product of the germanium lens substrate as the lens, the thickness of the accompanying coating sheet being 0.9‑1.5 mm; S2, coating a DLC film layer on the first surface; S3, coating an anti-reflection and anti-reflection film on the second surface. S4, after the coating is completed, wait for the vacuum chamber to cool to below 80°C and take out the lens. Through the DLC film layer as the outer film layer coated on the first surface and the anti-reflection and anti-reflection film as the inner film layer coated on the second surface, based on the test of the 8‑12 μm infrared band of the accompanying coating sheet, the transmittance in the 8‑12 μm infrared band can reach more than 91%. The combination of the inner film layer and the outer film layer can meet both the requirements of working in harsh environments and the requirements of infrared transmittance.

Description

Technical Field

[0001] The present disclosure relates to the infrared field, and more specifically to a method for preparing an 8-12 μm DLC reflective and anti-reflective film coated on a germanium lens substrate. Background Art

[0002] Germanium can be used in both long-wave infrared and medium-wave infrared. Germanium is widely used in medium- and long-wave infrared optical systems, but its dispersion characteristics vary significantly in different bands. The Abbe number of germanium at 3-5μm is 103, which is generally a negative group in optical systems; while its Abbe number at 8-12μm is 864, which is generally a positive group in optical systems. In the long-wave band, it can be used as a crown or positive element in an achromatic double lens. In the medium band, it can be used as a flint or negative element in an achromatic double lens. This change comes from the difference in the dispersion characteristics of germanium materials in these two bands. In the medium band, germanium is very close to its low absorption band, and the refractive index changes rapidly, resulting in a large dispersion, which makes germanium a negative optical power element in an achromatic double lens in the medium band.

[0003] As infrared technology becomes more and more widely used in military and civilian applications, the requirements for infrared coatings are getting higher and higher. The coating layer of the front lens of most optical systems needs to be able to operate normally for a long time in harsh environments, such as high-speed flight in the atmosphere, resistance to friction from foreign objects, resistance to rain immersion and corrosion in rainy and humid weather, etc. Summary of the invention

[0004] In view of the problems existing in the background technology, the purpose of the present disclosure is to provide a preparation method of 8-12μm DLC plus-minus-reflection anti-reflection film coated on a germanium lens substrate, which can meet both the requirements of working in harsh environments and infrared transmittance requirements.

[0005] Thus, a method for preparing 8-12μm DLC anti-reflection and anti-reflection film on a germanium lens substrate includes the following steps: S1, cleaning the surface of the accompanying plate of the germanium lens substrate and the product, the thickness of the accompanying plate is 0.9-1.5mm; S2, coating a DLC film layer on the first surface of the lens; S3, coating an anti-reflection and anti-reflection film on the second surface of the lens. S4, after the coating is completed, wait for the vacuum chamber to cool to below 80°C and take out the lens with both sides coated. Step S2 includes sub-steps: S21, placing the cleaned accompanying plating sheet and the product lens on the lower plate tray of the radio frequency plasma diamond-like coating equipment; S22, evacuating the radio frequency plasma diamond-like coating equipment, and then introducing argon gas for cleaning; S23, starting the radio frequency plasma diamond-like coating equipment, introducing 120sccm of methane and 10sccm of argon as reaction gas sources, turning on the radio frequency power supply, the radio frequency power of the radio frequency power supply is 700-800W, the deposition pressure is 0.1-10Pa, and the deposition time is 2800-3000s, thereby coating a DLC film layer on the first side of the lens; S24, after the deposition is completed, take out the lens containing the accompanying plating sheet and the product from the radio frequency plasma diamond-like coating equipment after cooling, and prepare to coat the second side of the lens. Step S3 includes sub-steps: S30, cleaning the surface of the lens coated with the DLC film layer on the first side including the accompanying coating sheet and the product; S31, placing the cleaned lens into a fixture, and hanging the fixture with the lens placed in the cavity of the vacuum coating machine, and setting the temperature of the cavity to 150°C; S32, starting the vacuum coating machine to evacuate, and the vacuum degree reaches 1×10 -3Pa, turn on the auxiliary coating ion source of the vacuum coating machine for cleaning, the cleaning time is 6 minutes, the anode voltage of the ion source is 220V, the anode current is 1.2-1.5A, the emitter current is 1.3-1.5A, and argon is used as the working gas; S33, maintain the aforementioned vacuum degree, evaporate the first Ge film layer on the second surface of the lens, the deposition rate of the first Ge film layer is 0.4nm / s, the film thickness of the first Ge film layer is controlled to be 20nm±1nm, and the ion source is assisted in evaporation; S34, evaporate the first ZnS film layer on the plated first Ge film layer, the deposition rate of the first ZnS film layer is 0.8nm / s, the film thickness of the first ZnS film layer is controlled to be 278nm±5nm, and the ion source is assisted in evaporation; S35, evaporate the second Ge film layer on the plated first ZnS film layer, the second Ge film The deposition rate of the layer is 0.4nm / s, and the film thickness of the second Ge film layer is controlled to be 160nm±4nm, and the ion source is assisted by evaporation; S36, a second ZnS film layer is evaporated on the plated second Ge film layer, and the deposition rate of the second ZnS film layer is 0.8nm / s, and the film thickness of the second ZnS film layer is controlled to be 583nm±5nm, and the ion source is assisted by evaporation; S37, a YbF3 film layer is evaporated on the plated second ZnS film layer, and the deposition rate of the YbF3 film layer is 0.6nm / s, and the film thickness of the YbF3 film layer is controlled to be 980nm±5nm, and the ion source is assisted by evaporation; S38, a third ZnS film layer is evaporated on the plated YbF3 film layer, and the deposition rate of the third ZnS film layer is 0.8nm / s, and the film thickness of the third ZnS film layer is controlled to be 137nm±4nm, and the ion source is assisted by evaporation.

[0006] The beneficial effects of the present disclosure are as follows: in the preparation method of coating 8-12μm DLC reflective anti-reflection film on the germanium lens substrate of the present disclosure, by coating the DLC film layer on the accompanying plate of the germanium lens substrate as the lens and the first surface of the product, the DLC film layer will serve as the outer film layer of the lens product, so that the product has the ability to operate normally for a long time in harsh environments, such as high-speed flight in the atmosphere, resistance to friction from foreign objects, resistance to immersion and corrosion of rainwater in rainy and humid weather, etc.; by coating the first Ge film layer with a film thickness of 20nm±1nm and the second surface of the germanium lens substrate as the lens and the product with a film thickness of 278nm±5nm The first ZnS film layer with a film thickness of 160nm±4nm, the second Ge film layer with a film thickness of 583nm±5nm, the second ZnS film layer with a film thickness of 980nm±5nm, the third ZnS film layer with a film thickness of 137nm±4nm, and the six film layers on the second surface will be used as the inner film layer of the lens product. This inner film layer is an anti-reflection and anti-reflection film. Through the DLC film layer as the outer film layer coated on the first surface and the anti-reflection and anti-reflection film as the inner film layer coated on the second surface, based on the test of the 8-12μm infrared band of the accompanying plated film, the transmittance of the 8-12μm infrared band can reach more than 91%. In other words, the combination of the inner film layer and the outer film layer can meet both the requirements of working in harsh environments and the requirements of infrared transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a structural schematic diagram of coating a DLC layer and an anti-reflection and anti-reflection film on both sides of a companion plate including a germanium lens substrate and a lens of a product according to the preparation method of coating 8-12 μm DLC and an anti-reflection and anti-reflection film on a germanium lens substrate disclosed in the present invention.

[0008] Figure 2 It is a curve diagram of the transmittance in the 8-12 μm infrared band of the accompanying coating sheet of Example 1, in which the DLC film layer and the anti-reflection and anti-reflection film are respectively coated on both sides. DETAILED DESCRIPTION

[0009] The accompanying drawings show embodiments of the present disclosure, and it will be understood that the disclosed embodiments are merely examples of the present disclosure, and the present disclosure can be implemented in various forms. Therefore, the specific details disclosed herein should not be interpreted as limiting, but merely as the basis for the claims and as a representative basis for teaching ordinary technicians in the field to implement the present disclosure in various ways.

[0010] [Preparation method of 8-12μm DLC anti-reflection film on germanium lens substrate]

[0011] The preparation method of coating 8-12 μm DLC with anti-reflection and anti-reflection film on germanium lens substrate disclosed in the present invention comprises the following steps: S1, cleaning the surface of the accompanying coating sheet and the product of the germanium lens substrate as the lens, wherein the thickness of the accompanying coating sheet is 0.9-1.5 mm; S2, coating a DLC film layer on the first surface of the lens; S3, coating an anti-reflection and anti-reflection film on the second surface of the lens; S4, after the coating is completed, waiting for the vacuum chamber to cool to below 80° C. and taking out the lens with both sides coated.

[0012] Step S2 includes sub-steps: S21, placing the cleaned accompanying plating sheet and the product lens on the lower plate tray of the radio frequency plasma diamond-like coating equipment; S22, evacuating the radio frequency plasma diamond-like coating equipment, and then introducing argon gas for cleaning; S23, starting the radio frequency plasma diamond-like coating equipment, introducing 120sccm of methane and 10sccm of argon as reaction gas sources, turning on the radio frequency power supply, the radio frequency power of the radio frequency power supply is 700-800W, the deposition pressure is 0.1-10Pa, and the deposition time is 2800-3000s, thereby coating a DLC film layer on the first side of the lens; S24, after the deposition is completed, take out the lens containing the accompanying plating sheet and the product from the radio frequency plasma diamond-like coating equipment after cooling, and prepare to coat the second side of the lens.

[0013] Step S3 includes sub-steps: S30, cleaning the surface of the lens coated with the DLC film layer on the first side including the accompanying coating sheet and the product; S31, placing the cleaned lens into a fixture, and hanging the fixture with the lens placed in the cavity of the vacuum coating machine, and setting the temperature of the cavity to 150°C; S32, starting the vacuum coating machine to evacuate, and the vacuum degree reaches 1×10 -3Pa, turn on the auxiliary coating ion source of the vacuum coating machine for cleaning, the cleaning time is 6 minutes, the anode voltage of the ion source is 220V, the anode current is 1.2-1.5A, the emitter current is 1.3-1.5A, and argon is used as the working gas; S33, maintain the aforementioned vacuum degree, evaporate the first Ge film layer on the second surface of the lens, the deposition rate of the first Ge film layer is 0.4nm / s, the film thickness of the first Ge film layer is controlled to be 20nm±1nm, and the ion source is assisted in evaporation; S34, evaporate the first ZnS film layer on the plated first Ge film layer, the deposition rate of the first ZnS film layer is 0.8nm / s, the film thickness of the first ZnS film layer is controlled to be 278nm±5nm, and the ion source is assisted in evaporation; S35, evaporate the second Ge film layer on the plated first ZnS film layer, the second Ge film The deposition rate of the layer is 0.4nm / s, and the film thickness of the second Ge film layer is controlled to be 160nm±4nm, and the ion source is assisted by evaporation; S36, a second ZnS film layer is evaporated on the plated second Ge film layer, and the deposition rate of the second ZnS film layer is 0.8nm / s, and the film thickness of the second ZnS film layer is controlled to be 583nm±5nm, and the ion source is assisted by evaporation; S37, a YbF3 film layer is evaporated on the plated second ZnS film layer, and the deposition rate of the YbF3 film layer is 0.6nm / s, and the film thickness of the YbF3 film layer is controlled to be 980nm±5nm, and the ion source is assisted by evaporation; S38, a third ZnS film layer is evaporated on the plated YbF3 film layer, and the deposition rate of the third ZnS film layer is 0.8nm / s, and the film thickness of the third ZnS film layer is controlled to be 137nm±4nm, and the ion source is assisted by evaporation.

[0014] In the preparation method of coating 8-12 μm DLC reflective anti-reflection film on the germanium lens substrate disclosed in the present invention, a DLC film layer is coated on the accompanying plate of the germanium lens substrate as a lens and the first surface of the product, and the DLC film layer will serve as the outer film layer of the lens product, so that the product has the ability to operate normally for a long time in harsh environments, such as high-speed flight in the atmosphere, resistance to friction from foreign objects, resistance to immersion and corrosion of rainwater in rainy and humid weather, etc.; a first Ge film layer with a film thickness of 20nm±1nm and a first Ge film layer with a film thickness of 278nm±5nm are coated on the accompanying plate of the germanium lens substrate as a lens and the second surface of the product. The six layers on the second surface will be used as the inner layer of the lens product, which is an anti-reflection and anti-reflection film. The DLC film layer as the outer film layer is plated on the first surface, and the anti-reflection and anti-reflection film as the inner film layer is plated on the second surface. Based on the test of the 8-12μm infrared band of the accompanying plated film, the transmittance of the 8-12μm infrared band can reach more than 91%. In other words, the combination of the inner and outer film layers can meet the requirements of both working in harsh environments and infrared transmittance.

[0015] In the preparation method of coating 8-12μm DLC anti-reflection film on the germanium lens substrate disclosed in the present invention, the DLC film layer coated on the accompanying plate of the germanium lens substrate serving as the lens and the first surface of the product is directly coated, so that the DLC film layer has the least effect on the transmittance of the product coated on both sides.

[0016] In the preparation method of coating 8-12 μm DLC plus-minus-reflection anti-reflection film on the germanium lens substrate disclosed in the present invention, the total thickness of the six film layers coated on the accompanying plate of the germanium lens substrate as a lens and the second surface of the product is 1519 nm±24 nm.

[0017] In the preparation method of coating 8-12 μm DLC with a reflective and anti-reflective film on a germanium lens substrate disclosed in the present invention, the surface cleaning of step S1 is beneficial to improving the surface state of the accompanying coating sheet and the first surface of the product, and helps to improve the bonding performance of the DLC film layer with the accompanying coating sheet and the first surface of the product.

[0018] In the preparation method of coating 8-12μm DLC plus-minus-reflection anti-reflection film on the germanium lens substrate disclosed in the present invention, in sub-step S22 of step S2, argon cleaning is the bombardment and sputtering of argon ions to make the impurities, oil molecules, and oxides adsorbed on the surface of the accompanying plated sheet and the product separate from the substrate surface, thereby greatly improving the interface state, which is helpful to improve the bonding performance of the DLC film layer formed in sub-step S23 with the accompanying plated sheet and the product. At the same time, through the bombardment of argon ions on the surface of the accompanying plated sheet and the product, the surface of the accompanying plated sheet and the product can be heated, which is helpful for the growth of the DLC film layer and reduces the growth stress of the DLC film layer.

[0019] In the preparation method of coating 8-12 μm DLC plus-minus-reflection anti-reflection film on germanium lens substrate disclosed in the present invention, in sub-step S23 of step S2, the radio frequency power supply generates glow discharge, so that the chemical source gas generates plasma, and the chemical source gas (methane, argon) decomposes into various neutral particles and charged particles. The particles collide with each other to cause a series of chemical reactions, and the positive ions (carbon ions, argon ions) in the plasma gather toward the lower plate tray to form a positive ion sheath on the surface of the accompanying plate and the product. The positive ions are accelerated in the sheath to collide with the surface of the accompanying plate and the product, forming high temperature and high pressure, and carbon ions are deposited on the accompanying plate and the product to form a carbon film, and the carbon film undergoes structural transformation to form a diamond-like film. The argon ions bombard the deposited carbon film during the film formation process, so that the formed diamond-like film is dense.

[0020] In the preparation method of coating 8-12 μm DLC with a reflective and anti-reflective film on a germanium lens substrate disclosed in the present invention, similarly, the surface cleaning of the sub-step S30 of step S3 is beneficial to improving the surface state of the accompanying coating sheet and the second surface of the product, and helps to improve the bonding performance of the six-layer film with the accompanying coating sheet and the second surface of the product.

[0021] In the preparation method of coating 8-12μm DLC with anti-reflection and anti-reflection film on the germanium lens substrate disclosed in the present invention, the temperature of the cavity in sub-step S31 of step S3 helps to eliminate the stress of the DLC film layer on the first surface of the accompanying coating sheet and the product, and also helps to grow the anti-reflection and anti-reflection film on the second surface of the accompanying coating sheet and the product.

[0022] In the preparation method of coating 8-12 μm DLC reflective anti-reflection film on the germanium lens substrate disclosed in the present invention, sub-step S32 of step S3 adopts an ion source for cleaning, and the bombardment and sputtering of argon ions ionized by the working gas argon will make the impurities, oil molecules, and oxides adsorbed on the surface of the second surface of the accompanying plated sheet and the product separate from the surface of the substrate, thereby greatly improving the interface state, which is conducive to improving the bonding performance between the first Ge film layer and the Ge lens substrate. At the same time, through the bombardment of argon ions on the second surface of the Ge lens substrate, the second surface of the Ge lens substrate can be heated, which is conducive to the growth of the first Ge film layer and the reduction of the growth stress of the first Ge film layer.

[0023] In the preparation method of coating 8-12 μm DLC plus-minus-reflection anti-reflection film on the germanium lens substrate disclosed in the present invention, in sub-steps S33 to S38 of step S3, ion source assisted evaporation bombards the second surface of the lens with ions to help the growth of the film layer, improve adhesion and hardness, and reduce film layer stress.

[0024] In the preparation method of coating 8-12μm DLC anti-reflection film on the germanium lens substrate disclosed in the present invention, the sub-step S33 of step S3 is to coat the first Ge film layer of the same material as the Ge lens substrate, thereby eliminating the stress caused by different materials, and the first Ge film layer has the smallest film thickness among the six film layers, which can make the transition from the Ge lens substrate to the first ZnS film layer by using the thinnest transition layer.

[0025] It is noted that in the preparation method of coating 8-12μm DLC anti-reflection film on the germanium lens substrate disclosed in the present invention, the accompanying coating sheet is a sheet with equal thickness and both the first and second surfaces are flat surfaces, and the product will be different from the accompanying coating sheet in shape and size according to actual needs. Based on the needs of the lens, in one example, the product has a convex first surface and a concave second surface.

[0026] In one example, in step S1 , the thickness of the accompanying coating of the germanium lens substrate is 1.0 mm.

[0027] In one example, in step S1, ultrasonic waves are used to clean the surface of the lens.

[0028] In one example, in sub-step S22 of step S2, the vacuum degree of the RF plasma diamond-like coating equipment reaches 5.0×10 -3 Pa.

[0029] In one example, in sub-step S22 of step S2, argon gas is introduced at 30 sccm and the cleaning time is 2 minutes.

[0030] In one example, in sub-step S23 of step S2, the RF power of the RF power supply is 750 W, the deposition pressure is 5 Pa, and the deposition time is 2900 s.

[0031] In one example, in sub-step S24 of step S2, cooling is performed for 30 minutes.

[0032] In one example, in sub-step S30 of step S3, ultrasonic waves are used to clean the surface of the lens.

[0033] In one example, in sub-step S32 of step S3, the anode current is 1.2A and the emitter current is 1.5A.

[0034] In one example, in sub-steps S32 to S38 of step S3, the ion source is a Hall ion source.

[0035] In one example, in sub-step S33, the thickness of the first Ge film layer is controlled to be 20nm; in sub-step S34, the thickness of the first ZnS film layer is controlled to be 278nm; in sub-step S35, the thickness of the second Ge film layer is controlled to be 160nm; in sub-step S36, the thickness of the second ZnS film layer is controlled to be 583nm; in sub-step S37, the thickness of the YbF3 film layer is controlled to be 980nm; in sub-step S38, the thickness of the third ZnS film layer is controlled to be 137nm.

[0036] In one example, in sub-step S33 and sub-step S35, a neutralizer is provided for the ion source, and the parameters of the neutralizer are: a neutralization current of 0.5A, argon gas is used to form the neutralization gas, and the flow rate of the neutralization gas is 10sccm; the anode voltage of the ion source is 150V, the anode current is 1.2A, argon gas is used as the working gas, and the argon gas flow rate is 100sccm.

[0037] In one example, in sub-step S34, sub-step S36 and sub-step S38, a neutralizer is provided for the ion source, and the parameters of the neutralizer are: the neutralization current is 0.5A, argon is used to form the neutralization gas, the flow rate of the neutralization gas is 10sccm, the anode voltage of the ion source is 180V, the anode current is 1.8A, argon is used as the working gas, and the argon flow rate is 100sccm.

[0038] In one example, in sub-step S37, a neutralizer is provided for the ion source, and the parameters of the neutralizer are: a neutralization current of 0.5A, argon gas is used to form the neutralization gas, and the flow rate of the neutralization gas is 10sccm; the anode voltage of the ion source is 120V, the anode current is 1.2A, argon gas is used as the working gas, and the argon gas flow rate is 100sccm.

[0039] In the above example using a neutralizer, the ionization of the argon gas in the ion source will form a near plasma, but these plasmas may contain excess charged ions, and the argon gas in the neutralizer is ionized to form electrons to neutralize the excess charged ions generated by the ion source, thereby eliminating the impact of the charged ions on the film layer of the evaporated film, thereby ensuring the quality of each film layer assisted by the ion source. Therefore, this effect can be achieved only at a very small flow ratio (1 / 10) of the neutralizing gas: working gas.

[0040] In one example, in sub-step S33 and sub-step S35 , the evaporation is performed by electron beam evaporation; in sub-step S34 , sub-step S36 , sub-step S38 , and sub-step S37 , the evaporation is performed by resistance heating evaporation.

[0041] [test]

[0042] Example 1

[0043] The preparation method of coating 8-12μm DLC anti-reflection film on germanium lens substrate adopts the following steps:

[0044] S1, using ultrasonic cleaning to treat the surfaces of the accompanying plating sheet of the germanium lens substrate and the product, the thickness of the accompanying plating sheet of the germanium lens substrate is 1.0 mm, the accompanying plating sheet is a sheet with equal thickness, the first surface and the second surface are both flat surfaces, and the product has a convex surface on the first surface and a concave surface on the second surface;

[0045] S2, coating a DLC film layer on the first surface of the lens, using the following sub-steps:

[0046] S21, placing the cleaned accompanying plating sheet and the product lens on the lower plate tray of the radio frequency plasma diamond-like coating equipment, the radio frequency plasma diamond-like coating equipment is a diamond-like hard carbon film coating machine manufactured by Chengdu Siwork Vacuum Technology Co., Ltd.;

[0047] S22, RF plasma diamond-like coating equipment vacuum pumping, vacuum pumping degree reaches 5.0×10 -3 Pa, then argon gas was introduced at 30 sccm for cleaning for 2 min;

[0048] S23, starting the radio frequency plasma diamond-like carbon coating equipment, introducing 120 sccm of methane and 10 sccm of argon as reaction gas sources, turning on the radio frequency power supply, the radio frequency power of the radio frequency power supply is 750 W, the deposition pressure is 5 Pa, and the deposition time is 2900 s, so as to coat a DLC film layer on the first surface of the lens;

[0049] S24, after the deposition is completed, the lens including the accompanying coating sheet and the product is taken out from the radio frequency plasma diamond-like coating device after cooling for 30 minutes, and the second side of the lens is prepared for coating;

[0050] S3, coating an anti-reflection and anti-reflection coating on the second surface of the lens, using the following sub-steps:

[0051] S30, using ultrasonic cleaning to clean the surface of the lens on which the first side DLC is plated, including the accompanying plated sheet and the product;

[0052] S31, placing the cleaned lens into a fixture, and hanging the fixture with the lens into the cavity of a vacuum coating machine, wherein the temperature of the cavity is set to 150° C. The vacuum coating machine is a vacuum coating machine with a Hall ion source equipped with a neutralizer manufactured and sold by Chengdu Siwork Vacuum Technology Co., Ltd., and the Hall ion source equipped with a neutralizer is purchased from Boton Optoelectronics Technology Co., Ltd.;

[0053] S32, vacuum coating machine starts to evacuate, and the vacuum degree reaches 1×10 -3 Pa, open the Hall ion source of the auxiliary coating of the vacuum coating machine for cleaning, the cleaning time is 6 minutes, the anode voltage of the ion source is 220V, the anode current is 1.2A, the emitter current is 1.5A, and argon is used as the working gas;

[0054] S33, maintaining the aforementioned vacuum degree, and evaporating a first Ge film layer on the second surface of the lens, the deposition rate of the first Ge film layer is 0.4 nm / s, the film thickness of the first Ge film layer is controlled to be 20 nm, and the evaporation is carried out by electron beam evaporation;

[0055] S34, vapor-depositing a first ZnS film layer on the plated first Ge film layer, wherein the deposition rate of the first ZnS film layer is 0.8 nm / s, and the film thickness of the first ZnS film layer is controlled to be 278 nm, and the vapor deposition adopts a resistance heating evaporation method;

[0056] S35, vapor-depositing a second Ge film layer on the plated first ZnS film layer, the deposition rate of the second Ge film layer is 0.4 nm / s, the film thickness of the second Ge film layer is controlled to be 160 nm, and the vapor deposition adopts an electron beam evaporation method;

[0057] S36, vapor-depositing a second ZnS film layer on the plated second Ge film layer, the deposition rate of the second ZnS film layer is 0.8 nm / s, the film thickness of the second ZnS film layer is controlled to be 583 nm, and the vapor deposition adopts a resistance heating evaporation method;

[0058] S37, vapor-depositing a YbF3 film layer on the plated second ZnS film layer, the deposition rate of the YbF3 film layer is 0.6 nm / s, the film thickness of the YbF3 film layer is controlled to be 980 nm, and the vapor deposition adopts a resistance heating evaporation method;

[0059] S38, vapor-depositing a third ZnS film layer on the plated YbF3 film layer, the deposition rate of the third ZnS film layer is 0.8 nm / s, the film thickness of the third ZnS film layer is controlled to be 137 nm, and the vapor deposition adopts a resistance heating evaporation method;

[0060] In sub-step S33 and sub-step S35, the parameters of the neutralizer are: the neutralization current is 0.5A, argon is used to form the neutralization gas, the flow rate of the neutralization gas is 10 sccm, the anode voltage of the ion source is 150V, the anode current is 1.2A, argon is used as the working gas, and the argon flow rate is 100 sccm;

[0061] In sub-step S34, sub-step S36 and sub-step S38, the parameters of the neutralizer are as follows: the neutralization current is 0.5A, argon is used to form the neutralization gas, the flow rate of the neutralization gas is 10 sccm, the anode voltage of the ion source is 180V, the anode current is 1.8A, argon is used as the working gas, and the argon flow rate is 100 sccm;

[0062] In sub-step S37, the parameters of the neutralizer are: the neutralization current is 0.5A, argon is used to form the neutralization gas, the flow rate of the neutralization gas is 10sccm, the anode voltage of the ion source is 120V, the anode current is 1.2A, argon is used as the working gas, and the argon flow rate is 100sccm;

[0063] S4, after the plating is completed, wait for the vacuum chamber to cool down to below 80°C and take out the lenses with both sides plated.

[0064] The structure of the lens with DLC film and six film layers coated on both sides prepared in Example 1 is as follows Figure 1 As shown schematically, Figure 2 The transmittance curve of the accompanying coating sheet prepared in Example 1 together with the DLC film layers on both sides and the six film layers (constituting the anti-reflection and anti-reflection film) is shown. Figure 2 It can be seen that in the 8-12μm band, the transmittance (arithmetic mean) can reach more than 91%.

[0065] According to the content of GJB2485-95 general specification for optical coatings, the performance of the accompanying coating film, the DLC coating on both sides and the overall performance of the six-layer coating were tested.

[0066] Water bubble test: The accompanying plating sheet prepared in Example 1 together with the DLC film layer and the six-layer film layer on both sides were subjected to a water bubble test with tap water for 10 minutes. No DLC film layer and the six-layer film layer were found to fall off the accompanying plating sheet, nor were the DLC film layer and the six-layer film layer found to be cracked.

[0067] Adhesion test: After the blister and salt spray tests with tap water were completed, 3M tape was pasted on the DLC film layer on the first side of the co-plating sheet by hand and the tape was pulled in the direction opposite to the pasting end, but the DLC film layer was not pulled up; for the second side of the co-plating sheet, 3M tape was pasted on the third ZnS film layer on the second side of the co-plating sheet by hand and the tape was pulled in the direction opposite to the pasting end, but the six film layers were not pulled up.

[0068] The water bubble test and tape pulling test show that the DLC film and the six-layer film on both sides of the plating sheet have good adhesion.

[0069] Thermal shock test: Thermal shock was conducted in a high and low temperature box at -40℃ to 85℃ for 24 hours. No DLC film and six-layer film were found to fall off from the accompanying plating sheet, and no DLC film and six-layer film were found to crack.

[0070] Constant temperature and humidity test: In a constant temperature and humidity chamber, at 50°C and 95% relative humidity for 48 hours, no DLC film and six-layer film were found to fall off from the accompanying plate, and no DLC film and six-layer film were found to crack.

[0071] Salt spray test: After 48 hours of neutral salt spray test, no DLC film and six-layer film were found to fall off from the accompanying coating sheet, and no DLC film and six-layer film were found to crack.

[0072] Low temperature test: In a low temperature box, at -40℃ for 48h, no DLC film and six-layer film were found to fall off from the accompanying plating sheet, and no DLC film and six-layer film were found to crack on the accompanying plating sheet;

[0073] High temperature test: at high temperature, 85℃ for 48h, no DLC film and six-layer film were found to fall off from the accompanying plating sheet, and no DLC film and six-layer film were found to crack.

[0074] The above detailed description is used to describe multiple exemplary embodiments, but this document is not intended to be limited to the explicitly disclosed combinations. Therefore, unless otherwise stated, the various features disclosed herein can be combined together to form multiple additional combinations that are not shown for the sake of simplicity.

Claims

1. A method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate, characterized in that: Includes steps: S1, cleaning the surface of the accompanying plating sheet and the product as the germanium lens substrate, the thickness of the accompanying plating sheet is 0.9-1.5mm; S2, coating a DLC film layer on the first surface of the lens, comprising the following sub-steps: S21, placing the cleaned accompanying plating sheet and the product lens on the lower plate tray of the radio frequency plasma diamond-like coating equipment; S22, the radio frequency plasma diamond-like coating equipment is evacuated and then argon gas is introduced for cleaning; S23, start the radio frequency plasma diamond-like coating equipment, introduce 120sccm of methane and 10sccm of argon as the reaction gas source, turn on the radio frequency power supply, the radio frequency power of the radio frequency power supply is 700-800W, the deposition pressure is 0.1-10Pa, and the deposition time is 2800-3000s, Thus, a DLC film layer is deposited on the first surface of the lens; S24, after the deposition is completed, the lens including the accompanying coating sheet and the product is taken out from the RF plasma diamond-like coating device after cooling, and the second side of the lens is prepared for coating; S3, coating an anti-reflection and anti-reflection film on the second surface of the lens, comprising the following sub-steps: S30, cleaning the surface of the lens coated with the first DLC film layer including the accompanying coating sheet and the product; S31, placing the cleaned lens into a fixture, and hanging the fixture with the lens placed into the cavity of the vacuum coating machine, and setting the temperature of the cavity to 150°C; S32, vacuum coating machine starts to evacuate, and the vacuum degree reaches 1×10 -3 Pa, open the auxiliary coating ion source of the vacuum coating machine for cleaning, the cleaning time is 6 minutes, The anode voltage of the ion source is 220V, the anode current is 1.2-1.5A, the emitter current is 1.3-1.5A, and argon is used as the working gas; S33, maintaining the aforementioned vacuum degree, evaporating a first Ge film layer on the second surface of the lens, the deposition rate of the first Ge film layer is 0.4 nm / s, the film thickness of the first Ge film layer is controlled to be 20 nm±1 nm, and the ion source is used to assist the evaporation; S34, evaporating a first ZnS film layer on the plated first Ge film layer, the deposition rate of the first ZnS film layer is 0.8 nm / s, the film thickness of the first ZnS film layer is controlled to be 278 nm±5 nm, and the evaporation is assisted by an ion source; S35, evaporating a second Ge film layer on the plated first ZnS film layer, the deposition rate of the second Ge film layer is 0.4 nm / s, the film thickness of the second Ge film layer is controlled to be 160 nm±4 nm, and the ion source is used to assist the evaporation; S36, evaporating a second ZnS film layer on the plated second Ge film layer, the deposition rate of the second ZnS film layer is 0.8 nm / s, the film thickness of the second ZnS film layer is controlled to be 583 nm±5 nm, and the ion source is used to assist the evaporation; S37, vapor-depositing a YbF3 film layer on the plated second ZnS film layer, the deposition rate of the YbF3 film layer is 0.6 nm / s, and the film thickness of the YbF3 film layer is controlled to be 980 nm±5 nm, Ion source assisted evaporation; S38, evaporating a third ZnS film layer on the plated YbF3 film layer, the deposition rate of the third ZnS film layer is 0.8 nm / s, the film thickness of the third ZnS film layer is controlled to be 137 nm±4 nm, and the ion source is used to assist the evaporation; S4, after the plating is completed, wait for the vacuum chamber to cool down to below 80°C and take out the lenses with both sides plated.

2. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In step S1 , the thickness of the accompanying coating layer of the germanium lens substrate is 1.0 mm.

3. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In step S1 and sub-step S30, ultrasonic waves are used to clean the surface of the lens.

4. The method for preparing a germanium lens substrate by coating 8-12 μm DLC for adding subtraction and anti-reflection according to claim 1, characterized in that: In sub-step S22, the RF plasma diamond-like coating equipment is evacuated to a vacuum degree of 5.0×10 -3 Pa; In sub-step S22, argon gas is introduced at 30 sccm and the cleaning time is 2 min; In sub-step S23, the RF power of the RF power source is 750 W, the deposition pressure is 5 Pa, and the deposition time is 2900 s; In sub-step S24, cooling is performed for 30 minutes.

5. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In sub-step S32, the anode current is 1.2A and the emitter current is 1.5A; In sub-steps S32 to S38, the ion source is a Hall ion source.

6. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In sub-step S33, the film thickness of the first Ge film layer is controlled to be 20 nm; In sub-step S34, the film thickness of the first ZnS film layer is controlled to be 278 nm; In sub-step S35, the film thickness of the second Ge film layer is controlled to be 160 nm; In sub-step S36, the film thickness of the second ZnS film layer is controlled to be 583 nm; In sub-step S37, the film thickness of the YbF3 film layer is controlled to be 980 nm; In sub-step S38, the film thickness of the third ZnS film layer is controlled to be 137 nm.

7. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In sub-step S33 and sub-step S35, a neutralizer is provided for the ion source, and the parameters of the neutralizer are: the neutralization current is 0.5A, argon is used to form the neutralization gas, and the flow rate of the neutralization gas is 10sccm, and the anode voltage of the ion source is 150V, the anode current is 1.2A, argon is used as the working gas, and the argon flow rate is 100sccm.

8. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In sub-step S34, sub-step S36 and sub-step S38, a neutralizer is provided for the ion source, and the parameters of the neutralizer are that the neutralization current is 0.5A, argon is used to form the neutralization gas, and the flow rate of the neutralization gas is 10sccm, and the anode voltage of the ion source is 180V, the anode current is 1.8A, argon is used as the working gas, and the argon flow rate is 100sccm.

9. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In sub-step S37, a neutralizer is provided for the ion source, and the parameters of the neutralizer are: a neutralization current of 0.5A, argon gas is used to form the neutralization gas, and the flow rate of the neutralization gas is 10sccm; the anode voltage of the ion source is 120V, the anode current is 1.2A, argon gas is used as the working gas, and the argon gas flow rate is 100sccm.

10. The method for preparing a 8-12 μm DLC anti-reflection film on a germanium lens substrate according to claim 1, characterized in that: In sub-step S33 and sub-step S35, the evaporation is performed by electron beam evaporation; In sub-step S34 , sub-step S36 , sub-step S38 and sub-step S37 , the vapor deposition adopts resistance heating evaporation.

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