Optical adhesive as well as preparation method and application thereof

Abstract

The invention relates to an optical adhesive as well as a preparation method and application thereof. The optical adhesive comprises As, S and I elements, wherein the atomic percent of As ranges from 10 at% to 50 at%; the atomic percent of S ranges from 10 at% to 68 at%; and the atomic percent range of I is 0-35 at%. The optical adhesive has good permeability in a full-waveband spectral range, meanwhile, the optical adhesive has a high refractive index and has better matching performance in the infrared field, experiments prove that the optical adhesive can effectively reduce Fresnel reflection between glass made of materials with different refractive indexes, and the quality of the glass is improved. And the maximum power threshold of the glass can be improved, so that the glass transmission efficiency is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of adhesives, and particularly relates to an optical adhesive and its preparation method and application. Background Art

[0002] The infrared band includes the near-infrared band (1-3 μm), the mid-infrared band (3-5 μm), and the far-infrared band (8-14 μm). For an optical imaging system, an optical imaging lens is often required to receive imaging light emitted by an imaging object and perform imaging. The image obtained by the optical imaging system will be affected by various factors that may cause aberrations, such as spherical aberration, coma aberration, astigmatism, field curvature, and distortion. In order to obtain a high-quality and low-distortion imaging effect, the optical lens needs to have advantages such as high compactness and high aberration correction. The lens gluing process can effectively eliminate various aberrations and improve the imaging quality. In addition, in an infrared fiber system, an infrared optical adhesive is also required for gluing fiber devices to improve the compactness and stability of the system.

[0003] The gluing process refers to a process of gluing two or more optical elements (such as lenses, filters, fiber end caps, fiber couplers, etc.) together with an adhesive to form a complete optical system. This process is often used in the manufacture of complex optical systems, such as telescopes, microscopes, photographic lenses, and fiber optic systems. The adhesive used in the gluing process needs to meet the requirements of having stable optical properties, good mechanical properties, long-term stability, and being easy to process. Common adhesives used in the gluing process include UV adhesives, silicone adhesives, acrylate adhesives, glass adhesives, etc. Adhesives commonly used in the near-infrared band include silicone adhesives, polyimide (PI), and epoxy resins.

[0004] The material of the adhesive has a certain influence on the transmitted band. The materials of commonly used adhesives can transmit in the visible light and near-infrared bands. These materials all have good transparency and optical properties and can maintain stability. However, all current adhesive materials contain a large amount of organic substances and water, so they cannot be applied to the mid- and far-infrared bands with longer wavelengths. In addition, in the field of research on the connection of infrared optical devices, in order to ensure the gluing quality, it is required that the refractive index of the adhesive must be close to that of the glued component, that is, an adhesive with a higher refractive index is needed.

[0005] How to reduce the power loss caused by large refractive index differences or Fresnel reflections caused by refractive index mismatches or large differences remains the core problem to be solved urgently in the mid- and far-infrared fields. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide an optical adhesive that can be applied to the full-band infrared field in view of the above-mentioned prior art.

[0007] The second technical problem to be solved by the present invention is to provide an optical adhesive that can change its fluidity with temperature changes in view of the above-mentioned prior art.

[0008] The third technical problem to be solved by the present invention is to provide a preparation method of the above-mentioned optical adhesive in view of the above-mentioned prior art.

[0009] The fourth technical problem to be solved by the present invention is to provide an application of the above-mentioned optical adhesive in view of the above-mentioned prior art.

[0010] The technical solutions adopted by the present invention to solve the above-mentioned first and second technical problems are as follows: An optical adhesive, characterized in that the optical adhesive contains As, S, and I elements; wherein:

[0011] The atomic percentage range of As is 10 at% to 50 at%;

[0012] The atomic percentage range of S is 10 at% to 68 at%;

[0013] The atomic percentage range of I is 0 to 35 at%.

[0014] Improved, in the present invention, the optical adhesive further includes a Se element; wherein:

[0015] The atomic percentage range of As is 10 at% to 50 at%.

[0016] The atomic percentage range of S is x;

[0017] The atomic percentage range of Se is y, where x + y = 10 at% to 68 at% and y > 0;

[0018] The atomic percentage range of I is 0 to 35 at%.

[0019] For the optical adhesive of the present application, the refractive index range of the optical adhesive is 2.11 to 2.24.

[0020] The technical solution adopted by the present invention to solve the above-mentioned third technical problem is as follows: A preparation method of the above-mentioned optical adhesive, characterized by including the following steps;

[0021] (1) Put each element of the optical adhesive into a glass tube according to the ratio;

[0022] (2) Open the mouth of the glass tube and evacuate the glass tube;

[0023] (3) Place the glass tube in a rocking furnace for rocking heating until each element in the glass tube is melted into a liquid state, and then cool the liquid substance in the glass tube to obtain the optical adhesive.

[0024] The technical solution adopted by the present invention to solve the above-mentioned fourth technical problem is as follows: An application of the above-mentioned optical adhesive, characterized in that the optical adhesive is used to bond at least two optical elements together.

[0025] Compared with the prior art, the advantages of the present invention are as follows: First, the optical adhesive of the present invention has good transmittance in the spectral range of the entire band. At the same time, the optical adhesive has a high refractive index and better matching in the infrared field. Experiments prove that the optical adhesive of the present application can effectively reduce the Fresnel reflection between glasses of different refractive index materials, and can increase the maximum power threshold of the glass, thereby improving the glass transmission efficiency.

[0026] Second, the optical adhesive of the present application is composed of arsenic (As), sulfur (S), iodine (I) or arsenic (As), sulfur (S), selenium (Se), iodine (I) elements. Among them, the arsenic element plays a role in forming glass, the S element is conducive to the glass being in a liquid state, the Se element plays a role in both forming glass and facilitating the glass to be in a liquid state. Due to their relatively strong ionic characteristics, the Se element and the I element can cut chemical bonds, thereby destroying the network and causing the glass to be in a liquid state, that is, the optical adhesive of the present application is in a liquid state, and its properties are between ordinary inorganic glass and organic polymers. At room temperature, the viscosity is greater than 1000 Pa·s, it has a low Tg, has fluidity at normal temperature, and its fluidity can change with temperature change, and the fluidity and viscosity of the adhesive can be controlled. If the two optical elements are not pasted in place, the fluidity of the optical adhesive can be improved by temperature change, and after readjusting the optical elements, they can be pasted; at the same time, the liquid state of the optical adhesive of the present application is more conducive to the operation during gluing, and it is not easy to have air gaps when bonding optical elements or lens lenses. Description of the Drawings

[0027] Figure 1 For the glass-forming phase diagram and Tg of the optical adhesive in Example 1;

[0028] Figure 2 For the viscosity test schematic diagram of the optical adhesive in Example 1;

[0029] Figure 3 For the refractive index distribution diagram of the optical adhesive in Example 1;

[0030] Figure 4 For the short-wave transmission curve in Example 1;

[0031] Figure 5 For the medium- and long-wave transmission curve in Example 1;

[0032] Figure 6 For the short-wave transmission curve in Example 2;

[0033] Figure 7 For the medium- and long-wave transmission curve in Example 2; Specific Embodiments

[0034] The present invention will be further described in detail below in conjunction with embodiments.

[0035] Embodiment 1

[0036] The optical adhesive of this embodiment is composed of three elements: arsenic (As), sulfur (S), and iodine (I), denoted as As-S-I. The atomic percentage of arsenic (As) is 10wt%, the atomic percentage of sulfur (S) is 70wt%, and the atomic percentage of iodine (I) is 20wt%. The feed amounts are 5.0279 g of arsenic (As), 6.4556 g of sulfur (S), and 8.5165 g of iodine (I).

[0037] The preparation method of the optical adhesive of this embodiment is as follows:

[0038] (1) Put the elements of the optical adhesive into a glass tube according to the ratio (5.0279 g of arsenic (As), 6.4556 g of sulfur (S), and 8.5165 g of iodine (I)). After the feeding is completed, perform a dehydroxylation pretreatment on the glass tube to prevent impurities such as water from entering the glass tube, and then seal the opening of the glass tube to prevent impurities from falling into the glass tube.

[0039] (2) Open the opening of the glass tube. Connect the opening of the glass tube and a vacuum pumping device (such as a vacuum pump) through a connecting tube, and perform a sealing treatment (such as applying silicone grease) between the connecting tube and the opening of the glass tube. Evacuate the glass tube (first use a mechanical pump to evacuate for 10 minutes, and then adjust the gear to a molecular pump to continue evacuating for 30 minutes). After completion, use a hydrogen-oxygen flame to seal off the connecting tube.

[0040] (3) Place the glass tube in a rocking furnace and melt it at 600 degrees Celsius for a set time (10 h). After all the elements are melted into a liquid state, then put it into water for cooling to obtain the optical adhesive.

[0041] Perform performance tests on the prepared optical adhesive: I.

[0043] Using the As-S-I optical adhesive, prepare AsS glass. Directly paste the AsS glass onto an 808 nm semiconductor laser using the above optical adhesive. Adjust the AsS glass so that the light emitted by the 808 nm semiconductor laser is perpendicularly incident on the AsS glass and measure. Before adding the optical adhesive, the output power of the AsS glass was measured to be 96.5 mW. After adding the As-S-I optical adhesive between the AsS glass and the semiconductor laser, the measured output power was 110.9 mW, and the transmittance increased by 15%. Experiments prove that the As-S-I optical adhesive can effectively eliminate the Fresnel reflection between the chalcogenide glass and the laser in the near-infrared region and improve the transmission efficiency. II.

[0045] Measurement of single - piece hydroxyl - free As using a 2.94μm solid - state laser 2 S 3 slice. The output power of the laser was measured to be 4.55W and the efficiency was 67% using a Thorlabs power meter, which served as a control. After that, the hydroxyl - free As 2 S 3 slices were coated with As - S - I optical adhesive on both sides and CaF 2 slices were adhered to both sides respectively. After the adhesive solidified, the whole was fixed. The output power of the laser was measured to be 8.5W and the efficiency was 80% using a Thorlabs power meter. Experiments proved that the As - S - I optical adhesive could effectively reduce the Fresnel reflection between glasses of different refractive index materials in the mid - infrared, and could increase the maximum power threshold of the glass, thus improving the glass transmission efficiency.

[0046] The above - mentioned hydroxyl - free As 2 S 3 slices were prepared by existing techniques and could be made by the method in Fabrication of As - S and As - Se Optical Fiber with Low Hydrogen Impurities Using Tellurium Tetrachloride (TeC14)). III.

[0048] Prepare four CaF 2 slices and two As 2 S 3 slices. One of the As 2 S 3 slices was clamped between two of the CaF 2 slices and fixed. Then its transmittance was tested by a 2.94μm laser. The other two CaF 2 slices were respectively adhered to both sides of the second As 2 S 3 using the above - mentioned As - S - I optical adhesive, and its transmittance was tested by a 2.94μm laser. After testing, the combined transmittance using the As - S - I optical adhesive increased by about 20%, which indicated that the As - S - I optical adhesive could effectively reduce the light loss caused by Fresnel reflection at the interface between chalcogenide glass and other low - refractive - index optical materials in the mid - infrared.

[0049] The applicant also conducted the following experiments and combined with the data of Example 1 to form Figure 1 .

[0050] One of the experiments is as follows: the atomic percentage of arsenic (As) is 10 wt%, the atomic percentage of sulfur (S) is 57 wt%, and the atomic percentage of iodine (I) is 33 wt%. Then the feed materials are 2.2151 g of arsenic (As), 5.4036 g of sulfur (S), and 12.3813 g of iodine (I);

[0051] One of the experiments is as follows: the atomic percentage of arsenic (As) is 45 wt%, the atomic percentage of sulfur (S) is 35 wt%, and the atomic percentage of iodine (I) is 20 wt%. Then the feed materials are 9.5892 g of arsenic (As), 3.1920 g of sulfur (S), and 7.2189 g of iodine (I);

[0052] One of the experiments is as follows: the atomic percentage of arsenic (As) is 15 wt%, the atomic percentage of sulfur (S) is 85 wt%. Then the feed materials are 5.8390 g of arsenic (As) and 14.1610 g of sulfur (S).

[0053] The preparation methods of the above experiments are the same as those in Example 1.

[0054] Figure 1 Based on the existing chalcogenide glass system, a detailed study was carried out on As-S-I glass, and a partial glass-forming region of the As-S-I system was preliminarily mapped. The black stars correspond to the compositions where crystallization occurs, the black circles represent the compositions that may form glass, and the black triangles are the optical adhesive As 10 S 70 I 20 ; Figure 1 It shows that the adhesive described in this application can be formed in the region shown in the figure.

[0055] Figure 2 It is the viscosity test and fitting curve of the As-S-I glass sample. It can be seen from the figure that when the temperature of this glass is 145 °C, its viscosity is 0.45 Pa·s, meeting the viscosity requirements of traditional optical adhesives.

[0056] Figure 3 It shows that the refractive index of the As 20 S 60 I 20 optical adhesive measured by an ellipsometer (IR-VASE Mark II of J.A.Woollam Company, USA) is 2.12.

[0057] Figure 4 It shows that the short-wave transmittance curve of the optical adhesive in this example can reach 83%.

[0058] Figure 5 It shows that the medium- and long-wave transmittance curves of the optical adhesive in this example can reach 73%.

[0059] Example 2

[0060] The optical adhesive of this embodiment is composed of three elements: arsenic (As), sulfur (S), selenium (Se), and iodine (I), which is denoted as As-S-Se-I. The atomic percentage of arsenic (As) is 15wt%, the atomic percentage of sulfur (S) is 50wt%, the atomic percentage of selenium (Se) is 15wt%, and the atomic percentage of iodine (I) is 20wt%. The raw materials are arsenic (As) 3.485g, sulfur (S) 4.9717g, selenium (Se) 3.6728g, and iodine (I) 7.8706g;

[0061] (1) Each element of the optical adhesive is added into a glass tube in proportion (arsenic (As) 3.485g, sulfur (S) 4.9717g, selenium (Se) 3.6728g, iodine (I) 7.8706g). After the addition is completed, the glass tube is subjected to a dehydroxylation pretreatment to prevent impurities such as water from entering the glass tube, and then the mouth of the glass tube is sealed to prevent impurities from falling into the glass tube;

[0062] (2) Open the mouth of the glass tube, connect the mouth of the glass tube to a vacuum pump (such as a vacuum pump) through a connecting tube, perform sealing treatment (such as applying silicone grease) between the connecting tube and the mouth of the glass tube, and evacuate the glass tube (first use a mechanical pump to evacuate for 10 minutes, and then continue to evacuate with a gear-modulated molecular pump for 30 minutes). After completion, use a hydrogen-oxygen flame to seal the connecting tube;

[0063] (3) Place the glass tube in a rocking furnace and melt it at 600 degrees Celsius for a set time (10 hours), so that all elements are melted into liquid form, and then put it into water for cooling, thereby obtaining the optical adhesive.

[0064] Performance test of the prepared optical adhesive:

[0065] Use the above As-S-Se-I optical cement to bond glasses with different refractive indices: prepare four ZnSe sheets and two As 2 S 3 piece, one of the pieces As 2 S 3 The sheet was sandwiched between two ZnSe sheets and fixed, and then its transmittance was tested by 10.6μm laser. The other two ZnSe sheets were respectively adhered to the second As sheet using the above As-S-Se-I optical adhesive. 2 S 3 On both sides of the film, the transmittance was tested by a 10.6μm laser. The transmittance of the combination using As-S-Se-I optical cement increased by about 15%, indicating that As-S-Se-I optical cement can effectively reduce the light loss caused by Fresnel reflection at the interface between chalcogenide glass and other low-refractive-index optical materials in the far infrared.

[0066] ​​Figure 6 The short-wave transmittance curve of the optical adhesive of this embodiment can reach 83%. Figure 7 The medium- and long-wave transmittance curve of the optical adhesive of this embodiment can reach 98%.

[0067] In addition, for the As-S-Se-I optical adhesive, the applicant also conducted the following experiments. The experimental method was the same as that of Example 2:

[0068] In one experiment, the atomic percentage of arsenic (As) was 15 wt%, the atomic percentage of sulfur (S) was 15 wt%, the atomic percentage of selenium (Se) was 50 wt%, and the atomic percentage of iodine (I) was 20 wt%. The feedstock was 2.778 g of arsenic (As), 1.1889 g of sulfur (S), 9.7591 g of selenium (Se), and 6.2739 g of iodine (I);

[0069] In one experiment, the atomic percentage of arsenic (As) was 12.8 wt%, the atomic percentage of sulfur (S) was 24.2 wt%, the atomic percentage of selenium (Se) was 53 wt%, and the atomic percentage of iodine (I) was 00 wt%. The feedstock was 2.668 g of arsenic (As), 2.1588 g of sulfur (S), 11.6426 g of selenium (Se), and 3.5306 g of iodine (I).

Claims

1. An optical adhesive, characterized in that: The optical adhesive contains As, S, and I elements; wherein: The atomic percentage of As ranges from 10 at% to 50 at%; The atomic percentage of S ranges from 10 at% to 68 at%; The atomic percentage of I ranges from 0 to 35 at %.

2. The optical adhesive according to claim 1, characterized in that: The optical adhesive further comprises Se element; wherein: The atomic percentage of As is in the range of 10 at % to 50 at %. The atomic percentage range of S is x; The atomic percentage range of Se is y, where x+y=10at% to 68at%, y>0; The atomic percentage of I ranges from 0 to 35 at %.

3. The optical adhesive according to claim 1 or 2, characterized in that: The refractive index of the optical adhesive is in the range of 2.11 to 2.

24.

4. A method for preparing the optical adhesive according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: (1) Adding various elements of the optical adhesive into a glass tube in proportion; (2) Open the mouth of the glass tube and evacuate the glass tube; (3) placing the glass tube in a rocking furnace for rocking heating until all elements in the glass tube are melted into liquid form, and then cooling the liquid substance in the glass tube to obtain the optical adhesive.

5. Use of the optical adhesive according to any one of claims 1 to 3, characterized in that: The optical adhesive is used to glue at least two optical elements together.

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