A chalcogenide glass IRG206 substrate long-wave infrared lens and its preparation method

Abstract

The present invention discloses a chalcogenide glass IRG206-based long-wave infrared lens and a preparation method thereof. The applicable anti-reflection band is 8-12 μm, belonging to the field of infrared optics. The long-wave infrared lens uses chalcogenide glass IRG206 as the substrate, and the same infrared anti-reflection film system structure is coated on both the front and back sides of the substrate: IRG206 / 0.251ZnS / 0.285Ge / 0.247ZnS / 0.760Ge / 0.359ZnS / 0.880YbF3 / 0.419ZnS / air. In the present invention, ZnS is used as the first layer of film, which plays a transitional role between the substrate and the film layer structure, thereby improving the adhesion of the film layer and reducing the occurrence of film peeling; the second to the sixth layers of film use Ge, ZnS, and YbF3 with good light transmission performance to increase the light transmittance; finally, ZnS is used as a protective film and coated on the outermost layer to reduce the influence of the external environment on the internal film layer. During the film coating process, ion source assistance is adopted to improve the bonding performance between the film layer and the substrate, improve the growth quality of the thin film, and reduce the residual stress of the film layer.

Description

Technical Field

[0001] The invention relates to a chalcogenide glass IRG206 substrate long-wave infrared lens and a preparation method thereof, belonging to the field of infrared optics. Background Art

[0002] Chalcogenide glass generally refers to compound glass composed mainly of Group VI elements such as S, Se, Te, and other elements, and As, Ge, Sb, Ga, and other elements. Its advantages include low temperature coefficient of refractive index, wide passing band, good achromatic and athermal properties, etc. It is an excellent type of infrared optical material and is widely used in infrared optics. Compared with infrared optical materials such as Ge, its preparation cost is lower, and it has good alternatives both in the research and development of infrared optics and in product manufacturing. For the existing chalcogenide glass IRG206 (As 40 Se 60 ) as the base and coated long-wave infrared lens, the transmittance of 8-12um is less than 50%, the film quality is low, and it cannot meet the work requirements. Summary of the invention

[0003] The present invention aims to improve the prior art and provide a chalcogenide glass IRG206 (As 40 Se 60 ) substrate long-wave infrared lens and its preparation method, so that the long-wave infrared lens has high light transmittance and high film quality.

[0004] To achieve the above object, the present invention is implemented by the following technical scheme: a chalcogenide glass IRG206 substrate long-wave infrared lens, the applicable anti-reflection band is 8-12um, the long-wave infrared lens uses chalcogenide glass IRG206 as the substrate, and the front and back sides of the substrate are coated with the same infrared anti-reflection film system structure, and the infrared anti-reflection film system structure is: IRG206 / 0.251ZnS / 0.285Ge / 0.247ZnS / 0.760Ge / 0.359ZnS / 0.880YbF 3 / 0.419ZnS / air, the number in front of the film material indicates the film thickness, in um.

[0005] Preferably, the thickness of the IRG206 substrate is 2 mm.

[0006] A method for preparing a long-wave infrared lens based on chalcogenide glass IRG206 comprises the following steps:

[0007] Step 1: Substrate pretreatment: Clean the surface of the substrate until no impurities are visible under a strong light, and then load the cleaned substrate into the coating machine;

[0008] Step 2: Coating preparation: ZnS, Ge and YbF 3The film materials were placed in different crucibles, the coating machine was evacuated, the substrate was preheated, and ZnS, Ge and YbF were coated in turn. 3 The film material is manually pre-melted, and the coating vacuum chamber is heated and kept at a constant temperature;

[0009] Step 3: Coating: ZnS, Ge, YbF 3 The film material is pre-melted in the coating machine before coating, and then the film layers are coated on the front and back sides of the substrate in sequence according to the film structure by electron beam heating evaporation. The coating temperature is 120°C. Hall ion source is used to assist the coating process. The evaporation rate is adjusted in real time during the evaporation of the film material to make it stable. After the coating is completed, when the temperature in the vacuum chamber is lower than 50°C, the lens is taken out.

[0010] Specifically, step 2 is as follows: clean the vacuum chamber of the coating machine, remove impurities in the evaporation source, and place ZnS, Ge and YbF 3 The film material is placed in different crucible positions, the coating machine is evacuated, the baking is turned on, the working speed is turned on, the baking working speed is 8 rpm, the constant temperature is 120℃, and the constant temperature time is 30-40min. Baking the substrate, when the baking temperature reaches 120℃, the vacuum chamber is kept at this temperature for 30-40min, and then ZnS, Ge, YbF 3 In order, manually pre-melt the film material in the crucible to a molten state: when the indoor vacuum reaches 6*E-3Pa, adjust the crucible position to the corresponding film material pot position, turn on the high voltage, close the electron gun baffle, turn on the electron gun, adjust the electron gun beam size, spot size and spot position, pre-melt the film material until the film material is in a molten state, turn off the high voltage, and turn off the electron gun.

[0011] Specifically, in step 3: ZnS, Ge, YbF 3 When the film material is pre-melted in the coating machine before plating, the electron beam current and time for ZnS film pre-melting are 20mA-40s and 30mA-40s respectively, the electron beam current and time for Ge film pre-melting are 120mA-30s and 140mA-30s respectively, and the electron beam current and time for YbF are 20mA-40s and 30mA-40s respectively. 3 The electron beam current and time during pre-melting of the film material are 30mA-30s and 40mA-30s respectively;

[0012] Specifically, in step three, a Hall ion source is used to assist plating during the coating process, the ion source anode voltage is 80V, the anode current is 0.6A, and the emitter voltage is 1.2A.

[0013] Specifically, in step three, the ZnS film layer is plated by electron beam heating, the electron beam current is 40 mA, the deposition rate is 1.2 nm / s, and the spot diameter of the electron beam during plating is 6-8 mm.

[0014] Specifically, in step three, the Ge film layer is plated by electron beam heating, the electron beam current is 160 mA, the deposition rate is 0.6 nm / s, and the spot diameter of the electron beam during plating is 2-3 mm.

[0015] Specifically, in step 3, YbF 3 The film layer is plated by electron beam heating, the electron beam current is 50mA, the deposition rate is 0.8nm / s, and the spot diameter of the electron beam during plating is 14-16mm.

[0016] The beneficial effects of the present invention are as follows: the infrared lens of the present invention uses chalcogenide glass IRG206 as the substrate, and the front and back sides of the substrate are coated with the same infrared anti-reflection film structure, and the film structure is composed of 7 layers of optical thin films made of different materials. The multilayer film system deposited on the substrate in sequence by a method of matching high refractive index and low refractive index can make the optical lens have a higher light transmittance, and the light transmittance of the lens after coating is more than 97%. The present invention uses ZnS, which is relatively dense, has good mechanical properties and has a certain connectivity with chalcogenide glass IRG206, as the first film layer, which plays a transition role between the substrate and the film layer structure, thereby improving the adhesion of the film layer and reducing the occurrence of film stripping; the second to sixth films use Ge, ZnS, Ge, ZnS and YbF with good light transmittance. 3 , increase the light transmittance; finally, ZnS is plated on the outermost layer as a protective film to reduce the impact of the external environment on the internal film layer. During the coating process, an ion source is used to assist in improving the bonding performance between the film layer and the substrate, improving the growth quality of the film, and reducing the residual stress of the film layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the membrane system of the present invention;

[0018] Figure 2 This is the transmittance curve of the chalcogenide glass IRG206 in the present invention.

[0019] Figure 3 It is a light transmittance curve diagram of the finished product of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with the embodiments and drawings, but the present invention is not limited in any way. Any changes or substitutions made based on the teachings of the present invention belong to the protection scope of the present invention.

[0021] Example 1: Figure 1-3 As shown, a chalcogenide glass IRG206 substrate long-wave infrared lens is applicable to the anti-reflection band of 8-12um. The long-wave infrared lens uses chalcogenide glass IRG206 as the substrate, and the same infrared anti-reflection film structure is coated on both the front and back sides of the substrate. The infrared anti-reflection film structure is:

[0022] IRG206 / 0.251ZnS / 0.285Ge / 0.247ZnS / 0.760Ge / 0.359ZnS / 0.880YbF 3 / 0.419ZnS / air, the number in front of the film material indicates the film thickness, in um.

[0023] Furthermore, the thickness of the IRG206 substrate is 2 mm.

[0024] A method for preparing a long-wave infrared lens based on chalcogenide glass IRG206 comprises the following steps:

[0025] Step 1: Substrate pretreatment: Use Fourier spectrometer to detect the transmittance of IRG206 substrate, such as Figure 2 As shown, the average transmittance in the 8-12um band is about 49%. Clean the substrate surface until no impurities can be seen under the irradiation of a strong light, and then load the cleaned substrate into the coating machine;

[0026] Step 2: Coating preparation: ZnS, Ge and YbF 3 The film materials were placed in different crucibles, the coating machine was evacuated, the substrate was preheated, and ZnS, Ge and YbF were coated in turn. 3 The film material is manually pre-melted, and the coating vacuum chamber is heated and kept at a constant temperature;

[0027] Step 3: Coating: ZnS, Ge, YbF 3 The film material is pre-melted in the coating machine before coating, and then the film layers are coated on the front and back sides of the substrate in sequence according to the film structure by electron beam heating evaporation. The coating temperature is 120°C. Hall ion source is used to assist the coating process. The evaporation rate is adjusted in real time during the evaporation of the film material to make it stable. After the coating is completed, when the temperature in the vacuum chamber is lower than 50°C, the lens is taken out. Further, step two is specifically: clean the vacuum chamber of the coating machine, clean the impurities in the evaporation source, and place ZnS, Ge and YbF 3 The film material is placed in different crucible positions, the coating machine is evacuated, the baking is turned on, the working speed is turned on, the baking working speed is 8 rpm, the constant temperature is 120℃, and the constant temperature time is 30-40min. Baking the substrate, when the baking temperature reaches 120℃, the vacuum chamber is kept at this temperature for 30-40min, and then ZnS, Ge, YbF 3 Manually pre-melt the film material in the crucible to a molten state in the following order:

[0028] Pre-melting ZnS film material: When the indoor vacuum reaches 6*E-3Pa, adjust the crucible position to the ZnS film material pot position, turn on the high voltage, close the electron gun baffle, turn on the electron gun, adjust the electron gun beam size, spot size and spot position, pre-melt the ZnS film material until the ZnS film material is in a molten state, turn off the high voltage, and turn off the electron gun.

[0029] Pre-melting Ge film material: After the pre-melting of ZnS film material is completed, the crucible position is adjusted to the Ge film material pot position, the high voltage is turned on, the electron gun baffle is closed, the electron gun is turned on, the electron gun beam size, spot size and spot position are adjusted, and the Ge film material is pre-melted until the Ge film material is in a molten state, the high voltage is turned off, and the electron gun is turned off.

[0030] Pre-melted YbF 3 Film material: After the Ge film material is pre-melted, the crucible position is adjusted to YbF 3 Film material pot position, turn on the high voltage, close the electron gun baffle, turn on the electron gun, adjust the electron gun beam size, spot size and spot position, and 3 The film material is pre-melted until YbF 3 The film material is in a molten state, turn off the high voltage and the electron gun.

[0031] Further, in step 3: ZnS, Ge, YbF 3 When the film material is pre-melted in the coating machine before plating, the electron beam current and time for ZnS film pre-melting are 20mA-40s and 30mA-40s respectively, the electron beam current and time for Ge film pre-melting are 120mA-30s and 140mA-30s respectively, and the electron beam current and time for YbF are 20mA-40s and 30mA-40s respectively. 3 The electron beam current and time during pre-melting of the film material are 30mA-30s and 40mA-30s respectively;

[0032] Furthermore, in step three, a Hall ion source is used to assist the plating process, the ion source anode voltage is 80V, the anode current is 0.6A, and the emitter voltage is 1.2A.

[0033] Furthermore, in step three, the ZnS film layer is plated by electron beam heating, the electron beam current is 40 mA, the deposition rate is 1.2 nm / s, and the spot diameter of the electron beam during the plating is 6-8 mm.

[0034] Furthermore, in step three, the Ge film layer is plated by electron beam heating, the electron beam current is 160 mA, the deposition rate is 0.6 nm / s, and the spot diameter of the electron beam during plating is 2-3 mm.

[0035] Furthermore, in step 3, YbF 3The film layer is plated by electron beam heating, the electron beam current is 50mA, the deposition rate is 0.8nm / s, and the spot diameter of the electron beam during plating is 14-16mm.

[0036] The performance test of the coated lenses is as follows:

[0037] Transmittance test: Use Fourier spectrometer to measure the transmittance of coated lenses, such as Figure 3 As shown, the average transmittance in the 8-12um band is greater than 97%.

[0038] Adhesion test: According to the test method in 3.4.1.1 of GJB2485-1995 standard, use 3M tape to firmly stick to the surface of the film layer, and pull it up vertically and quickly, and there is no film peeling phenomenon.

[0039] Wet heat test: Place the coated lens in a wet heat test box at 50°C and 95% humidity. Keep it at constant temperature and humidity for 24 hours and then take it out. Observe the surface of the film after taking it out. There should be no discoloration, cracking or delamination.

[0040] High and low temperature test: Put the coated lens into a high and low temperature test box, and leave it at a low temperature of -62℃ and a high temperature of 70℃ for 2 hours respectively. Take it out after it cools down to room temperature. Check if there is any peeling, blistering, cracking or delamination on the film layer.

[0041] Wear test: Wrap two layers of dry absorbent gauze outside the rubber friction head, rub the film layer along the same track under a pressure of 4.9N, with a distance of 20mm, and move back and forth 25 times. There is no scratch or other damage to the film layer.

[0042] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made in form and details without departing from the scope defined by the claims of the present invention.

Claims

1. A chalcogenide glass IRG206 substrate long-wave infrared lens, Features: The applicable anti-reflection band is 8-12um. The long-wave infrared lens uses chalcogenide glass IRG206 as the substrate. The front and back sides of the substrate are coated with the same infrared anti-reflection film structure. The infrared anti-reflection film structure is: IRG206 / 0.251ZnS / 0.285Ge / 0.247ZnS / 0.760Ge / 0.359ZnS / 0.880YbF 3 / 0.419ZnS / air, the number in front of the film material indicates the film thickness, in um.

2. The chalcogenide glass IRG206 substrate long-wave infrared lens according to claim 1, Features: The thickness of the IRG206 substrate is 2 mm.

3. A method for preparing a long-wave infrared lens based on chalcogenide glass IRG206 according to claim 1 or 2, Features: The steps include: Step 1: Substrate pretreatment: Clean the surface of the substrate, and no impurities can be seen under the irradiation of a strong light, and then load the cleaned substrate into the coating machine; Step 2: Coating preparation: ZnS, Ge and YbF 3 The film materials were placed in different crucibles, the coating machine was evacuated, the substrate was preheated, and ZnS, Ge and YbF were coated in turn. 3 The film material is manually pre-melted, and the coating vacuum chamber is heated and kept at a constant temperature; Step 3: Coating: ZnS, Ge, YbF 3 The film material is pre-melted in the coating machine before coating, and then the film layers are coated on the front and back sides of the substrate in sequence according to the film structure by electron beam heating evaporation. The coating temperature is 120°C. Hall ion source is used to assist the coating process. The evaporation rate is adjusted in real time during the evaporation of the film material to make it stable. After the coating is completed, when the temperature in the vacuum chamber is lower than 50°C, the lens is taken out.

4. The method for preparing a chalcogenide glass IRG206 substrate long-wave infrared lens according to claim 3, Features: Step 2 is as follows: clean the vacuum chamber of the coating machine, remove impurities in the evaporation source, and place ZnS, Ge and YbF 3 The film material is placed in different crucible positions, the coating machine is evacuated, the baking is turned on, the working speed is turned on, the baking working speed is 8 rpm, the constant temperature is 120℃, the constant temperature time is 30-40min, the substrate is baked, when the baking temperature reaches 120℃, the vacuum chamber is kept at this temperature for 30-40min, and then ZnS, Ge, YbF 3 Manually pre-melt the film material in the crucible to a molten state: wait until the vacuum degree in the room reaches 6*10 -3 When Pa, the crucible position is adjusted to the corresponding film material pot position, the high voltage is turned on, the electron gun baffle is closed, the electron gun is turned on, the electron gun beam size, spot size and spot position are adjusted, the film material is pre-melted until the film material is in a molten state, the high voltage is turned off, and the electron gun is turned off.

5. The method for preparing a chalcogenide glass IRG206 substrate long-wave infrared lens according to claim 3, Features: Step 3: ZnS, Ge, YbF 3 When the film material is pre-melted in the coating machine before plating, the electron beam current and time for ZnS film pre-melting are 20mA-40s and 30mA-40s respectively, the electron beam current and time for Ge film pre-melting are 120mA-30s and 140mA-30s respectively, and the electron beam current and time for YbF are 20mA-40s and 30mA-40s respectively. 3 The electron beam current and time during pre-melting of the film material are 30mA-30s and 40mA-30s respectively.

6. The method for preparing a chalcogenide glass IRG206 substrate long-wave infrared lens according to claim 3, Features: In step three, the anode voltage of the Hall ion source is 80V, the anode current is 0.6A, and the emitter voltage is 1.2A.

7. The method for preparing a chalcogenide glass IRG206 substrate long-wave infrared lens according to claim 3, Features: In step three, the ZnS film layer is plated by electron beam heating, the electron beam current is 40 mA, the deposition rate is 1.2 nm / s, and the spot diameter of the electron beam during plating is 6-8 mm.

8. The method for preparing a chalcogenide glass IRG206 substrate long-wave infrared lens according to claim 3, Features: In step three, the Ge film layer is plated by electron beam heating, the electron beam current is 160 mA, the deposition rate is 0.6 nm / s, and the spot diameter of the electron beam during plating is 2-3 mm.

9. The method for preparing a chalcogenide glass IRG206 substrate long-wave infrared lens according to claim 3, Features: In step three, YbF 3 The film layer is plated by electron beam heating, the electron beam current is 50mA, the deposition rate is 0.8nm / s, and the spot diameter of the electron beam during plating is 14-16mm.

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