Chalcogenide optical glass, preparation method thereof and optical element

Abstract

The present invention provides a chalcogenide optical glass, a preparation method thereof and an optical element. In terms of molar percentage, the chalcogenide optical glass comprises: Ge: 10-20%, preferably 11-19%; Ga: 2-15%, preferably 2-10%; Te: 70-85%, preferably 72-83%; Pb: 2-10%, preferably 2-8%; Ag: 0-8%, preferably 0-6%. The chalcogenide optical glass of the present invention has a high refractive index, a high Abbe number, a low glass transition temperature, and good infrared transmittance in the 3-20 μm band. The chalcogenide optical glass of the present invention is very suitable for precision molding.

Description

Technical Field

[0001] The invention relates to a chalcogenide optical glass and a preparation method and an optical element thereof, belonging to the technical field of optical glass. Background Art

[0002] Sulfur-based optical glass is an infrared optical material with excellent performance. It is widely used in military guidance, gun aiming, and civilian temperature measurement, security, and intelligent driving. With the rapid advancement of detector technology and the urgent demand for low-cost markets, higher requirements are placed on the performance and cost of sulfide optical glass. The refractive index, as the main performance of optical glass, is an important indicator that affects optical imaging. The higher the refractive index, the easier the optical design becomes. It can optimize the optical design, reduce the number of lens elements, and reduce the difficulty of lens processing and lens cost. At the same time, the hot infrared precision molding technology in recent years has become an important factor in reducing the cost of infrared lenses. This technology requires a lower glass transition temperature and can better achieve mass production. Therefore, it is urgent to develop sulfide optical glass with a higher refractive index and a lower glass transition temperature, which will promote the development of infrared technology and realize people's yearning for smart life.

[0003] CN113735440A discloses a Ge-based chalcogenide glass and a preparation method thereof, which mainly comprises the following component ratios: Ge: 5At% to 40At%; Ga: 2At% to 20At%; Ag: 2At% to 15At%; Te: 30At% to 80At%, with a refractive index of 3.47 to 3.5 at 10 μm and a glass transition temperature of 150 to 160° C. The invention introduces Ag element alone into the Ge-Ga-Te system, which reduces the glass forming performance, is easy to crystallize, and is difficult to achieve mass production of glass.

[0004] CN113912289A discloses a multi-element high refractive index chalcogenide glass and its preparation method, the components and proportions are as follows: Ge: 15At%-20At%; Sb: 15At%-20.2At%; Se: 50At%-60At%; Te: 2At%-5At%; Sn: 2At%-3At%; Pb: 1.5At%-2At%, the refractive index at 10μm is 2.93-3.16, and the glass transition temperature is 200-235°C. The invention contains a large amount of Se with low polarizability, which cannot effectively increase the refractive index of the glass, and the large amount of Se element introduced will make the long-wave cutoff point of the glass move forward, and the infrared transmission band of the glass will become narrower. Summary of the invention

[0005] Problem that the invention aims to solve

[0006] In view of the technical problems existing in the prior art, the present invention first provides a chalcogenide optical glass. The chalcogenide optical glass of the present invention has a high refractive index, a high Abbe number, a low glass transition temperature, and good infrared transmittance in the 3-20 μm band. The chalcogenide optical glass of the present invention is very suitable for precision molding.

[0007] Furthermore, the present invention also provides a method for preparing chalcogenide optical glass, which is simple and easy to implement, and the raw materials are easy to obtain, and is suitable for mass production.

[0008] Solutions for solving problems

[0009] The present invention provides a chalcogenide optical glass, which comprises, in terms of molar percentage:

[0010] Ge: 10-20%, preferably 11-19%;

[0011] Ga: 2-15%, preferably 2-10%;

[0012] Te: 70-85%, preferably 72-83%;

[0013] Pb: 2-10%, preferably 2-8%;

[0014] Ag: 0 to 8%, preferably 0 to 6%.

[0015] According to the chalcogenide optical glass of the present invention, the sum of the contents of Pb and Ag, Σ(Pb+Ag), is 2 to 15%, preferably 2 to 10%, in molar percentage.

[0016] The ratio of the sum of the contents of Pb and Ag to the sum of the contents of Ge, Ga and Te (Σ(Pb+Ag) / Σ(Ge+Ga+Te)) is 0.01 to 0.12, preferably 0.01 to 0.10.

[0017] According to the chalcogenide optical glass of the present invention, the refractive index of the chalcogenide optical glass at a wavelength of 10 μm is 3.5-3.9; the Abbe number of the chalcogenide optical glass is 190-230, preferably the Abbe number is 200-220.

[0018] According to the chalcogenide optical glass of the present invention, the glass transition temperature of the chalcogenide optical glass is 140-170°C, preferably 145-160°C; the linear expansion coefficient at 20-120°C is 140×10 -7 / K~180×10 -7 / K, preferably 145×10 -7 / K~176×10 -7 / K.

[0019] According to the chalcogenide optical glass of the present invention, the average transmittance of the chalcogenide optical glass in the 3-20 μm band is 40% to 55%, preferably 45% to 53%.

[0020] The present invention also provides a method for preparing the chalcogenide optical glass according to the present invention, which comprises the following steps:

[0021] The glass raw materials of each component are weighed and mixed according to the proportion, and then packaged with the purified material in a sealed container. Preferably, the vacuum degree of the sealed container is 10 -5 Below mbar;

[0022] The sealed container is melted, cooled and solidified, and then annealed to obtain the chalcogenide optical glass.

[0023] According to the preparation method of the present invention, the purified substance is not in direct contact with the glass raw material; the purified substance includes titanium wire; preferably, based on the total mass of the glass raw material as 100%, the content of the purified substance is 0.12-0.2wt%.

[0024] According to the preparation method of the present invention, the annealing and cooling method includes using liquid nitrogen or ice water for annealing and cooling.

[0025] According to the preparation method of the present invention, the melting temperature is 850-1100°C, and the melting time is 10-20h; the temperature of the cooling and solidification is 350-600°C; the temperature of the annealing and cooling is 130-150°C, and the annealing and cooling rate is 1-20°C / h.

[0026] The present invention also provides an optical element, which comprises the chalcogenide optical glass according to the present invention.

[0027] Effects of the Invention

[0028] The chalcogenide optical glass of the present invention has a high refractive index, a high Abbe number, a low glass transition temperature, and good infrared transmittance in the 3-20 μm band. The chalcogenide optical glass of the present invention is very suitable for precision molding.

[0029] Furthermore, the preparation method of the chalcogenide optical glass of the present invention is simple and easy, the raw materials are easy to obtain, and it is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The Fourier infrared spectrum of the chalcogenide optical glass of Example 2 is shown.

[0031] Figure 2 A refractive index graph of the chalcogenide optical glass of Example 2 is shown. DETAILED DESCRIPTION

[0032] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. The word "exemplary" used here means "used as an example, embodiment or illustrative". Any embodiment described here as "exemplary" is not necessarily interpreted as being superior or better than other embodiments.

[0033] In addition, in order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details. In other examples, methods, means, equipment and steps well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0034] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0035] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0036] In this specification, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0037] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints numerical values ​​A and B.

[0038] In this specification, when "normal temperature" or "room temperature" is used, the temperature may be 10-40°C.

[0039] The present invention first provides a chalcogenide optical glass, which comprises, in terms of molar percentage:

[0040] Ge: 10-20%, preferably 11-19%;

[0041] Ga: 2-15%, preferably 2-10%;

[0042] Te: 70-85%, preferably 72-83%;

[0043] Pb: 2-10%, preferably 2-8%;

[0044] Ag: 0 to 8%, preferably 0 to 6%.

[0045] The Ge element is an essential component of the present invention, is the main network former of the glass, and is a key component for improving the strength of the glass, improving the crystallization performance and the infrared transmission performance. In the present invention, if the Ge content is too low, the glass strength will be weakened, and if the Ge content is too high, the glass transmission performance will be reduced, and it is easy to crystallize, which is difficult to mass produce. Therefore, in terms of molar percentage, it is most ideal to control the Ge content to 10-20%, preferably 11-19%, such as 12-18%.

[0046] Te element is a good ligand of glass, and its main function is to improve glass viscosity and crystallization performance. If the Te content is higher than 85%, the glass is easy to crystallize, and the glass structure is loose due to the larger atomic radius of Te, thereby reducing the glass transition temperature. If the Te content is lower than 70%, the glass refractive index cannot be improved, and the crystallization performance of the glass will also be reduced. Therefore, in terms of molar percentage, the Te content in the present invention is 70-85%, preferably 72-83%, for example: 73-80%.

[0047] Ga is mainly an intermediate in glass, has high polarizability, and can improve the refractive index of glass. At the same time, proper addition of Ga can improve the crystallization performance of glass, while excessive addition will lead to a sharp deterioration of the crystallization performance of glass. Therefore, in terms of molar percentage, the content of Ga is 2 to 15%, preferably 2 to 10%, for example, 3 to 8%.

[0048] The Pb element has a large relative atomic mass. The introduction of Pb atoms can effectively increase the average atomic mass of the entire glass system, thereby increasing the specific gravity of the glass, reducing the propagation speed of light, and increasing the refractive index of the glass. However, Pb cannot be used as a major component of glass. Therefore, in terms of molar percentage, the content of Pb is controlled to be 2-10%, preferably 2-8%, for example, 3-7%.

[0049] The introduction of a small amount of Ag element can improve the stability of the glass, and Ag has high polarizability, which can also effectively increase the refractive index of the glass. However, excessive Ag introduction will destroy the network structure of the glass, and will form partial phase separation in the glass, making the glass easy to crystallize. Therefore, the introduction amount of Ag needs to be controlled to 0-8%, preferably 0-6%, for example 3-5%.

[0050] In some specific embodiments, in terms of molar percentage, the sum of the contents of Pb and Ag, ∑(Pb+Ag), is 2-15%, preferably 2-10%, for example, 3-8%, 4-6%, etc. The present invention can improve the glass transition temperature, reduce the difficulty of chemical processing, and optimize the thermal stability and chemical stability of the glass by controlling ∑(Pb+Ag) to 2-15%. Further, in the present invention, the ratio of the sum of the contents of Pb and Ag to the sum of the contents of Ge, Ga and Te, ∑(Pb+Ag) / ∑(Ge+Ga+Te), is 0.01-0.12, preferably 0.01-0.10, for example, 0.02-0.08, 0.04-0.06. The present invention can improve the crystallization performance of the glass, improve the infrared transmittance, and reduce the difficulty of melting the glass by controlling ∑(Pb+Ag) / ∑(Ge+Ga+Te) to 0.01-0.12.

[0051] Further, in the present invention, the refractive index of the chalcogenide optical glass at a wavelength of 10 μm is 3.5 to 3.9; the Abbe number of the chalcogenide optical glass is 190 to 230, preferably 200 to 220. The glass transition temperature of the chalcogenide optical glass is 140 to 170°C, preferably 145 to 160°C; the linear expansion coefficient at 20 to 120°C is 140×10 -7 / K~180×10 -7 / K, preferably 145×10 -7 / K~176×10 -7 / K. The average transmittance of the chalcogenide optical glass in the 3-20 μm band is 40% to 55%, preferably 45% to 53%.

[0052] The present invention also provides a method for preparing chalcogenide optical glass, which is characterized by comprising the following steps:

[0053] The glass raw materials of each component are weighed and mixed according to the proportion, and then packaged with the purified material in a sealed container. Preferably, the vacuum degree of the sealed container is 10 -5 Below mbar;

[0054] The sealed container is melted, cooled and solidified, and then annealed to obtain the chalcogenide optical glass.

[0055] In some specific embodiments, the purified substance is not in direct contact with the glass raw material; the purified substance includes titanium wire; preferably, based on the total mass of the glass raw material as 100%, the content of the purified substance is 0.12-0.2wt%. The present invention can remove oxygen impurities by using an appropriate amount of purified substance, so that the chalcogenide optical glass of the present invention has excellent transmittance.

[0056] In some specific embodiments, the annealing cooling method includes using liquid nitrogen or ice water for annealing cooling.

[0057] Specifically, in the present invention, the melting temperature is 850-1100°C, and the melting time is 10-20h; the temperature of the cooling and solidification is 350-600°C; the temperature of the annealing cooling is 130-150°C, and the annealing cooling rate is 1-20°C / h.

[0058] Further, in the present invention, the preparation method of the present invention comprises the following steps:

[0059] 1) Mixing ingredients and vacuum sealing: Weigh glass raw materials, including Ge, Ga, Te, Pb, and Ag, with a purity of ≥99.999%, mix the glass raw materials thoroughly, put purified substances in a container, and then use hydrogen-oxygen flame to seal the mixture and purified substances in a vacuum chamber with a degree of 10 -5 In a closed container below mbar;

[0060] 2) Mixed material melting and quenching: Place the packaged sealed container in a rocking furnace for high-temperature melting, the melting temperature is 850-1100°C, the melting time is 10-20 hours, and the melting process is rocked throughout to ensure that the raw materials are evenly mixed; then cool down, and when the melting temperature drops to 350-600°C, take out the sealed container to cool and solidify, and form a semi-finished glass product in the sealed container;

[0061] 3) Annealing and cooling: Place the sealed container containing the semi-finished glass product into an annealing furnace. The annealing and cooling temperature is 130 to 150°C and the annealing and cooling rate is -1 to -20°C / h. After the temperature drops to room temperature, take out the sealed container from the annealing furnace.

[0062] 4) Sampling: Knock open the sealed container containing the annealed glass semi-finished product to obtain the chalcogenide optical glass.

[0063] The above-mentioned chalcogenide optical glass is cut into predetermined sizes, and then a release agent is evenly coated on the surface, and then it is heated, softened, and press-formed to produce preform blanks of various lenses and prisms such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. After these blanks are cleaned, ground, polished, and other processes, they can be made into glass preforms.

[0064] The glass preform is heated and pressed on a precision molding device to produce lenses and prisms of various shapes such as concave meniscus lenses, convex meniscus lenses, biconvex lenses, biconcave lenses, plano-convex lenses, and plano-concave lenses. The surface of the obtained optical element can also be coated with an anti-reflection film or a DLC film.

[0065] In addition, the present invention also provides an optical element, which comprises the chalcogenide optical glass according to the present invention.

[0066] Example

[0067] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0068] In the following, the examples listed in the table will describe the present invention in more detail for reference by other technicians. It should be noted that the glass component contents in Examples 1 to 9# are expressed in molar percentages, and the protection scope of the present invention is not limited to the examples.

[0069] Examples 1-9

[0070] The preparation method of the chalcogenide optical glass of Examples 1-9 is implemented according to the following steps:

[0071] 1) Batching and vacuum sealing: weigh the raw materials according to the components and molar contents of each embodiment in Table 1, the purity of the raw materials is ≥99.999%, and mix the glass raw materials thoroughly to obtain a mixture. Then, suspend a purified titanium wire in a container, and the content of the purified material is 0.15wt% based on the total mass of the glass raw materials as 100%. Then, the mixture and the titanium wire are sealed in a vacuum of 10 -5 In a closed container below mbar;

[0072] 2) Mixed material melting and quenching: The sealed container is placed in a rocking furnace for high-temperature melting. The melting temperature is 1000°C and the melting time is 18 hours. The melting process is rocked throughout to ensure that the raw materials are evenly mixed. When the melting temperature drops to 500°C, the sealed container is taken out and quickly cooled and solidified to form a semi-finished glass product in the sealed container;

[0073] 3) Annealing and cooling: Place the sealed container containing the semi-finished glass product into an annealing furnace at an annealing temperature of 150°C and an annealing cooling rate of -10°C / h. After the temperature drops to room temperature, take out the sealed container from the annealing furnace;

[0074] 4) Sampling: The sealed container containing the semi-finished glass after annealing was opened to obtain the chalcogenide optical glass. The results are shown in Table 1 below.

[0075] Comparative Examples 1-3

[0076] The chalcogenide optical glasses of Comparative Examples 1-3 were prepared by the preparation methods of Examples 1-9 and according to the raw material ratios in Table 2.

[0077] Performance Testing

[0078] The optical glasses prepared in Examples 1-9 and Comparative Examples 1-3 were tested for performance using the following testing methods.

[0079] 1. Refractive index n 10μm

[0080] The test was carried out according to the test method of GB / T 34184 standard, and the refractive index curve of Example 2 was measured. The results are shown in Tables 1 and Figure 2 shown.

[0081] 2. Abbe number υ 10μm

[0082] The test was carried out according to the test method of GB / T 34184 standard. The results are shown in Table 1.

[0083] 3. Glass transition temperature Tg

[0084] The glass transition temperature (Tg) was measured using a TMA tester from PE Company of the United States in accordance with the GB / T7962.16-2010 test method. The results are shown in Table 1.

[0085] 4. Linear expansion coefficient α 20-120℃

[0086] Linear expansion coefficient (α 20～120 ) The TMA tester of PE Company of the United States was used for measurement according to the test method of GB / T7962.16-2010. The results are shown in Table 1.

[0087] 5. Average transmittance in the 3-20μm band

[0088] The transmittance was measured using a Fourier spectrophotometer from Thermo Fisher Scientific Inc., USA, in accordance with the test method of GB / T 36403 standard. The chalcogenide optical glass of Example 2 was tested. The results are as follows: Figure 1 shown.

[0089] Depend on Figure 1 It can be seen that the average transmittance of the chalcogenide optical glass of the present invention in the 3-20 μm band is 40%-55%, indicating that the chalcogenide optical glass of the present invention has a high average transmittance and a wide infrared transmission band, and is suitable for preparing infrared optical materials.

[0090] Table 1: Examples 1-9

[0091]

[0092] It can be seen from Table 1 that the various properties of the chalcogenide optical glass prepared in various embodiments of the present invention are relatively excellent. Figure 2 It can be seen that the present invention can obtain a chalcogenide optical glass with a high refractive index. In addition, the chalcogenide optical glass of the present invention has a high Abbe number and a low glass transition temperature, so the chalcogenide optical glass of the present invention is very suitable for precision molding.

[0093] Table 2: Comparative Examples 1-3

[0094]

[0095] It can be seen from Table 2 that when only Ge, Ga and Te are contained, the refractive index is too low to meet the requirements of the optical element. Comparative Example 2 does not contain Pb, and its refractive index is also low, and the linear expansion coefficient is too high. In Comparative Example 3, the Pb content is too low, the Ag content is too high, and its refractive index is too low, and the linear expansion coefficient is too high.

[0096] Industrial Applicability

[0097] The chalcogenide optical glass and the preparation method thereof of the present invention can be produced industrially, and the optical element of the present invention can be used in optical systems of various optical instruments.

[0098] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0099] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A chalcogenide optical glass, characterized in that: In terms of molar percentage, the chalcogenide optical glass comprises the following components: composition: Ge: 10-20%; Ga: 2-15%; Te: 70-85%; Pb: 3-10%; Ag: 0-8%; The ratio of the sum of the contents of Pb and Ag to the sum of the contents of Ge, Ga and Te (Σ(Pb+Ag) / Σ(Ge+Ga+Te)) is 0.01 to 0.

12.

2. The chalcogenide optical glass according to claim 1, characterized in that: In terms of molar percentage, the chalcogenide optical glass comprises the following components: composition: Ge: 11-19%; Ga: 2-10%; Te: 72-83%; Pb: 3-8%; Ag: 0~6%.

3. The chalcogenide optical glass according to claim 1 or 2, characterized in that: In terms of molar percentage, the sum of the contents of Pb and Ag (∑(Pb+Ag)) is 2 to 15%.

4. The chalcogenide optical glass according to claim 3, characterized in that: In terms of molar percentage, the sum of the contents of Pb and Ag ∑(Pb+Ag) is 2 to 10%; The ratio of the sum of the contents of Pb and Ag to the sum of the contents of Ge, Ga and Te (Σ(Pb+Ag) / Σ(Ge+Ga+Te)) is 0.01 to 0.

10.

5. The chalcogenide optical glass according to claim 1 or 2, characterized in that: The refractive index of the chalcogenide optical glass at a wavelength of 10 μm is 3.5-3.9; the Abbe number of the chalcogenide optical glass is 190-230.

6. The chalcogenide optical glass according to claim 5, characterized in that: The Abbe number of the chalcogenide optical glass is 200-220.

7. The chalcogenide optical glass according to claim 1 or 2, characterized in that: The glass transition temperature of the chalcogenide optical glass is 140-170°C; the linear expansion coefficient at 20-120°C is 140×10 -7 / K~180×10 -7 / K.

8. The chalcogenide optical glass according to claim 7, characterized in that: The glass transition temperature of the chalcogenide optical glass is 145-160°C; the linear expansion coefficient at 20-120°C is 145×10 -7 / K ~176×10 -7 / K.

9. The chalcogenide optical glass according to claim 1 or 2, characterized in that: The average transmittance of the chalcogenide optical glass in the 3-20 μm band is 40%-55%.

10. The chalcogenide optical glass according to claim 9, characterized in that: The average transmittance of the chalcogenide optical glass in the 3-20 μm band is 45%-53%.

11. A method for preparing a chalcogenide optical glass according to any one of claims 1 to 10, characterized in that: The following steps are involved: The glass raw materials of each component are weighed and mixed according to the proportion, and then sealed in a sealed container with the purified substance; The sealed container is melted, cooled and solidified, and then annealed to obtain the chalcogenide optical glass.

12. The preparation method according to claim 11, characterized in that: The vacuum degree of the sealed container is 10 -5 Below mbar.

13. The preparation method according to claim 11, characterized in that: The purification substance is not in direct contact with the glass raw material; the purification substance includes titanium wire.

14. The preparation method according to claim 13, characterized in that: Based on the total mass of the glass raw material being 100%, the content of the purified substance is 0.12-0.2 wt %.

15. The preparation method according to any one of claims 11 to 14, characterized in that: The annealing cooling method includes using liquid nitrogen or ice water for annealing cooling.

16. The preparation method according to any one of claims 11 to 14, characterized in that: The melting temperature is 850-1100° C., and the melting time is 10-20 hours; the temperature of the cooling and solidification is 350-600° C.; the temperature of the annealing and cooling is 130-150° C., and the annealing and cooling rate is 1-20° C. / h.

17. An optical element, characterized in that: The invention comprises the chalcogenide optical glass according to any one of claims 1 to 10.

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