阅读说明：本技术 一种锗基底8-12um红外窗口片及其制备方法 (Germanium-based 8-12um infrared window sheet and preparation method thereof ) 是由 姜海 侯强 刘瑞斌 于 2020-04-30 设计创作，主要内容包括：本发明属于光学薄膜领域,具体涉及一种锗基底8-12um红外窗口片及其制备方法。窗口片以单晶锗为基底,基底的两侧均镀有单层的增透膜结构,两侧膜结构的入射角均定义为0°±10°。其制备方法是先对基片进行擦拭放置到镀膜机中,再将增透膜材料预熔,再采用真空热蒸发法进行镀膜,单晶锗基底的两侧分别镀有1层增透膜结构,增透膜为硫化锌材料时膜层厚度为1.083-1.162um,增透膜为KRS-6材料时膜层厚度为1.090-1.145um。该窗口片可应用到8-12um红外探测系统中,也可以用到夜视仪中,因其镀膜设计简单,镀膜材料选择普通,膜层牢固度高等优点,大大降低了窗口片制作的周期与成本。(The invention belongs to the field of optical films, and particularly relates to a germanium-based 8-12um infrared window sheet and a preparation method thereof. The window sheet takes single crystal germanium as a substrate, two sides of the substrate are plated with single-layer antireflection film structures, and the incident angles of the two film structures are defined as 0 +/-10 degrees. The preparation method comprises the steps of wiping a substrate, placing the substrate in a film coating machine, pre-melting antireflection film materials, and coating the substrate by a vacuum thermal evaporation method, wherein two sides of a single crystal germanium substrate are respectively coated with 1 layer of antireflection film structure, the thickness of the film layer is 1.083-1.162 micrometers when the antireflection film is made of zinc sulfide materials, and the thickness of the film layer is 1.090-1.145 micrometers when the antireflection film is made of KRS-6 materials. The window piece can be applied to an 8-12um infrared detection system and can also be applied to a night vision device, and the manufacturing period and the manufacturing cost of the window piece are greatly reduced due to the advantages of simple coating design, common coating material, high film firmness and the like.)

1. The utility model provides an infrared window piece of germanium basement 8-12um which characterized in that: the window sheet takes single crystal germanium as a substrate, and both sides of the substrate are plated with single-layer antireflection film structures.

2. A germanium-based 8-12um infrared window sheet according to claim 1, wherein: the thickness of the film layer is 1.083-1.162um when the anti-reflection film is made of zinc sulfide material, and the thickness of the film layer is 1.090-1.145um when the anti-reflection film is KRS-6 material.

3. A germanium-based 8-12um infrared window sheet according to claim 1, wherein: the average transmittance of the infrared window sheet is greater than 95%, and the extreme value transmittance is greater than 98%.

4. A germanium-based 8-12um infrared window sheet according to claim 1, wherein: the thickness of the monocrystalline germanium is in the range of 10-30 mm in diameter and 1-2 mm in thickness.

5. A germanium-based 8-12um infrared window sheet according to claim 1, wherein: the incident angles of the antireflection film structures on both sides of the window sheet are defined to be 0 +/-10 degrees.

6. A preparation method of a germanium substrate 8-12um infrared window sheet is characterized by comprising the following steps: the method comprises the following steps:

the method comprises the following steps: preparing a substrate: wiping the surface of the monocrystalline germanium, putting the wiped lens into a plate support, and putting the plate support on a workpiece disc of a film coating machine;

step two: preparation before plating: placing the anti-reflection film material in a thermal evaporation crucible, vacuumizing the background of a vacuum chamber, and pre-melting the anti-reflection film material in a molten state;

step three: film coating: coating by adopting a vacuum thermal evaporation method;

two sides of the single crystal germanium substrate are respectively plated with 1 layer of antireflection film structure, and the two sides are plated with films;

setting the thickness of a coating film, wherein the thickness of the coating film is 1.083-1.162um when the antireflection film is made of a zinc sulfide material, and the thickness of the coating film is 1.090-1.145um when the antireflection film is made of a KRS-6 material.

7. The method for preparing the germanium-based 8-12um infrared window sheet as claimed in claim 6, wherein: ethanol and diethyl ether (6-8) are adopted for wiping in the first step: (4-2) wiping the surface of the monocrystalline germanium by using the solution with the volume ratio; the antireflection film material is zinc sulfide or KRS-6;

the purity of the zinc sulfide material is 99.99 percent; KRS-6 is a mixture of 44.4 mass percent of thallium bromide and 55.6 mass percent of thallium chloride, and the vacuumizing condition in the second step is that the background of the vacuum chamber is vacuumized to (0.8-1.0) E-3Pa, the temperature of a deposition area is 130-150 ℃, and the constant temperature is 30-40 min.

8. The method for preparing the germanium-based 8-12um infrared window sheet as claimed in claim 6, wherein: the third concrete step is:

step a: presetting coating conditions before coating;

step b: controlling the evaporation rate of the anti-reflection film material by using a quartz crystal film thickness controller;

step c: heating the thermal evaporation crucible to a glowing state, opening a baffle plate, and starting coating; bombarding the film layer by using a Hall ion source to increase the compactness of the film layer.

9. The method for preparing the germanium-based 8-12um infrared window sheet as claimed in claim 8, wherein: the film coating conditions of the step a are that the central wavelength of the antireflection film is 10 +/-0.01 um, the incident angle range is 0 +/-10 degrees, and the medium air is incident;

and b, controlling the evaporation rate to be 1-1.2 nm/s, controlling the thermal evaporation voltage to be 5-6V, controlling the current to be 800-plus-one 1000A, controlling the argon partial pressure to be (2.0-2.5) E-2Pa, maintaining the indoor vacuum to be (2.1-2.6) E-2Pa, and controlling the argon filling amount to be 20-40 SCCM by the quartz crystal film thickness controller.

10. The method for preparing the germanium-based 8-12um infrared window sheet as claimed in claim 8, wherein: and c, ion energy adopted by the Hall ion source in the step c is 200-250 eV, ion beam current is 30-40 mA, and ion distribution deviation is 15-20%.

Technical Field

The invention belongs to the field of optical films, and particularly relates to a germanium-based 8-12um infrared window sheet and a preparation method thereof.

Background

An 8-12um infrared window sheet is a common infrared passive device and is used for isolating an internal system of a detector from an external environment. At present, the period and cost for manufacturing a window sheet are restricted by the selection of a substrate material and the selection of an antireflection film material in practical application, a conventional infrared antireflection film generally selects germanium and ytterbium fluoride as high-refractive index and low-refractive index materials, the designed layer number is 6-8, the thickness is 3-4um, such as CN108627889 published in 2018, 10, 9 and the transmittance of the conventional infrared antireflection film is about 94%, 8 irregular film layers need to be deposited on two surfaces of the substrate respectively, the film layers are more, the thickness is thicker, the preparation cost is high, the production time is long, and the conventional infrared antireflection film is not beneficial to large-scale popularization.

Disclosure of Invention

The purpose of the invention is as follows:

the invention aims to reduce the production cost of manufacturing 8-12um infrared window sheets, and aims to provide a germanium substrate 8-12um infrared window sheet with low cost performance and high transmittance and a preparation method thereof.

The technical scheme is as follows:

the invention is realized by the following technical scheme:

an infrared window sheet with a germanium substrate of 8-12um is characterized in that single-crystal germanium is used as the substrate of the window sheet, and both sides of the substrate are plated with single-layer antireflection film structures.

Furthermore, the thickness of the film layer is 1.083-1.162um when the antireflection film is made of zinc sulfide material, and the thickness of the film layer is 1.090-1.145um when the antireflection film is made of KRS-6 material.

Furthermore, the average transmittance of the infrared window sheet is greater than 95%, and the extreme value transmittance is greater than 98%.

Furthermore, the thickness of the single crystal germanium ranges from 10 mm to 30 mm in diameter and 1 mm to 2 mm in thickness.

Further, the incident angles of the antireflection film structures on both sides of the window sheet are defined to be between 0 ° ± 10 °.

A preparation method of an infrared window sheet with a germanium substrate of 8-12um comprises the following steps:

the method comprises the following steps: preparing a substrate: wiping the surface of the monocrystalline germanium, putting the wiped lens into a plate support, and putting the plate support on a workpiece disc of a film coating machine;

step two: preparation before plating: placing the anti-reflection film material in a thermal evaporation crucible, vacuumizing the background of a vacuum chamber, and pre-melting the anti-reflection film material in a molten state;

step three: film coating: coating by adopting a vacuum thermal evaporation method;

two sides of the single crystal germanium substrate are respectively plated with 1 layer of antireflection film structure, and the two sides are plated with films;

setting the thickness of a coating film, wherein the thickness of the coating film is 1.083-1.162um when the antireflection film is made of a zinc sulfide material, and the thickness of the coating film is 1.090-1.145um when the antireflection film is made of a KRS-6 material.

Further, ethanol and diethyl ether (6-8) are adopted for wiping in the step one: (4-2) wiping the surface of the monocrystalline germanium by using the solution with the volume ratio; the antireflection film material is zinc sulfide or KRS-6; the purity of the zinc sulfide material is 99.99 percent; KRS-6 is a mixture of 44.4 mass percent of thallium bromide and 55.6 mass percent of thallium chloride, and the vacuumizing condition in the second step is that the background of the vacuum chamber is vacuumized to (0.8-1.0) E-3Pa, the temperature of a deposition area is 130-150 ℃, and the constant temperature is 30-40 min.

Further, the third step is specifically as follows:

step a: presetting coating conditions before coating;

step b: controlling the evaporation rate of the anti-reflection film material by using a quartz crystal film thickness controller;

step c: heating the thermal evaporation crucible to a glowing state, opening a baffle plate, and starting coating; bombarding the film layer by using a Hall ion source to increase the compactness of the film layer.

Further, the film coating conditions in the step a are that the central wavelength of the antireflection film is 10 +/-0.01 um, the incident angle range is 0 +/-10 degrees, and medium air is incident;

and b, controlling the evaporation rate to be 1-1.2 nm/s, controlling the thermal evaporation voltage to be 5-6V, controlling the current to be 800-plus-one 1000A, controlling the argon partial pressure to be (2.0-2.5) E-2Pa, maintaining the indoor vacuum to be (2.1-2.6) E-2Pa, and controlling the argon filling amount to be 20-40 SCCM by the quartz crystal film thickness controller.

Furthermore, the Hall ion source in the step c adopts 200-250 eV of ion energy, 30-40 mA of ion beam current and 15-20% of ion distribution deviation.

The advantages and effects are as follows:

the invention has the following advantages and beneficial effects:

the window piece can be applied to an 8-12um infrared detection system and can also be applied to a night vision device, and the window piece greatly reduces the period and cost for manufacturing the window piece due to the advantages of simple coating design, common coating material and high film firmness.

Compared with the prior art in which multiple layers are arranged, the invention selects zinc sulfide or KRS-6 material, the designed layer number is 1, the thickness of the film layer is 1.083-1.162um when the antireflection film is zinc sulfide material, the thickness of the film layer is 1.090-1.145um when the antireflection film is KRS-6 material, the average transmittance is greater than 95%, and the extreme value transmittance is greater than 98%. Saving cost, reducing the steps of the preparation process and the production time, and being beneficial to expanding production.

Drawings

FIG. 1 is a schematic view of the structure of a window sheet of the present invention;

FIG. 2 is a spectrum of a germanium wafer without an anti-reflection coating;

FIG. 3 is a spectrum of a single-layer zinc sulfide double-coated film of example 1;

FIG. 4 is a spectrum of a single-layer zinc sulfide double-coated film of example 2;

FIG. 5 is a spectrum of a single-layer zinc sulfide double-coated film obtained in example 3;

FIG. 6 is a spectrum of a single-layer zinc sulfide double-coated film of example 4;

FIG. 7 is a spectrum of KRS-6 coated on both sides with a single layer in example 5;

FIG. 8 is a spectrum of KRS-6 coated on both sides with a single layer in example 6;

FIG. 9 is a spectrum of KRS-6 coated on both sides with a single layer in example 7;

FIG. 10 is a spectrum of KRS-6 coated on both sides with a single layer in example 8;

FIG. 11 is a spectrum of a film with a thickness of 0.96 μm obtained when zinc sulfide is used as the coating material in example 9;

FIG. 12 is a spectrum of a film thickness of 1.25 μm when zinc sulfide is used as the coating material in example 9;

FIG. 13 is a spectrum of KRS-6 as the coating material in example 9, with a film thickness of 0.96 um;

FIG. 14 is a spectrum of a film with a thickness of 1.25um obtained by using KRS-6 as the coating material in example 9.

Description of reference numerals:

1. monocrystalline germanium, 2, antireflection coating structure.

Detailed Description

As shown in figure 1, the infrared window sheet with a germanium substrate of 8-12um takes single-crystal germanium as the substrate, and both sides of the substrate are plated with a single-layer antireflection film structure.

According to the invention, the single crystal germanium 1 is used as a substrate, the zinc sulfide or KRS-6 is used as a coating material, and the two sides of the substrate are both plated with the single-layer antireflection film structure 2, so that the period and the cost for manufacturing the window sheet are greatly reduced.

The thickness of the film layer is 1.083-1.162um when the anti-reflection film is made of zinc sulfide material, and the thickness of the film layer is 1.090-1.145um when the anti-reflection film is KRS-6 material.

The invention uses zinc sulfide and KRS-6 as film materials which are important factors for designing a simple antireflection film, and the average transmittance of 8-12um after double-sided coating is more than 95 percent.

The infrared window sheet is mainly characterized in that single-layer coating films are arranged on two sides of a substrate, the adopted antireflection film material is more superior, and the film layer is simplified and has better transmittance.

The average transmissivity of the infrared window sheet is greater than 95%, and the extremum transmissivity is greater than 98%.

The transmissivity of zinc sulfide material and KRS-6 material (44.4% TlBr and 55.6% TlCl) as antireflection films can be greatly improved.

The thickness of the single crystal germanium 1 as a substrate is in the range of 10 to 30 mm in diameter and 1 to 2 mm in thickness.

The incident angles of the antireflection film structures 2 on both sides of the window sheet are both defined to be between 0 ° ± 10 °.

A preparation method of an infrared window sheet with a germanium substrate of 8-12um comprises the following steps:

the method comprises the following steps: preparing a substrate: wiping the surface of the monocrystalline germanium, placing the wiped lens into a wafer support, and placing the wafer support on a workpiece disc of an existing film plating machine.

Ethanol and diethyl ether (6-8) are adopted for wiping in the first step: (4-2) wiping the surface of the monocrystalline germanium by using the solution with the volume ratio; the antireflection film material is zinc sulfide or KRS-6;

the purity of the zinc sulfide material is 99.99 percent; KRS-6 is a mixture of 44.4% thallium bromide and 55.6% thallium chloride by mass fraction.

Step two: preparation before plating: placing the anti-reflection film material in a thermal evaporation crucible, vacuumizing the background of the vacuum chamber, and pre-melting the anti-reflection film material in a molten state.

And the vacuumizing condition in the second step is that the background of the vacuum chamber is vacuumized to (0.8-1.0) E-3Pa, the temperature of a deposition area is 130-150 ℃, and the constant temperature is kept for 30-40 min.

Step three: film coating: coating by adopting a vacuum thermal evaporation method;

two sides of the single crystal germanium substrate are respectively plated with 1 layer of antireflection film structure 2, and the two sides are plated with films;

setting the thickness of a coating film, wherein the thickness of the coating film is 1.083-1.162um when the antireflection film is made of a zinc sulfide material, and the thickness of the coating film is 1.090-1.145um when the antireflection film is made of a KRS-6 material.

The third concrete step is:

step a: presetting coating conditions before coating; the coating conditions of the step a are that the central wavelength of the antireflection film is 10 +/-0.01 um, the incident angle range is 0 +/-10 degrees, and the medium air is incident.

Step b: controlling the evaporation rate of the anti-reflection film material by using a quartz crystal film thickness controller; and b, controlling the evaporation rate to be 1-1.2 nm/s, controlling the thermal evaporation voltage to be 5-6V, controlling the current to be 800-plus-one 1000A, controlling the argon partial pressure to be (2.0-2.5) E-2Pa, maintaining the indoor vacuum to be (2.1-2.6) E-2Pa, and controlling the argon filling amount to be 20-40 SCCM by the quartz crystal film thickness controller.

Step c: heating the thermal evaporation crucible to a glowing state, opening a baffle plate, and starting coating; bombarding the film layer by using a Hall ion source to increase the compactness of the film layer. And c, ion energy adopted by the Hall ion source in the step c is 200-250 eV, ion beam current is 30-40 mA, and ion distribution deviation is 15-20%.

As shown in fig. 2, the transmittance of the germanium sheet without the antireflection film is only 46.9%.