High refractive index core glass for fiber optic taper and method of making and use thereof

Abstract

The application relates to the technical field of glass manufacturing, in particular to high-refractive-index core glass for fiber light cones and a preparation method and application thereof. The core glass has a refractive index of greater than or equal to 1.81, a thermal expansion coefficient of (85-89) * 10 ‑7 -6 / ℃, a glass transition temperature of greater than or equal to 550 DEG C, good thermal processing performance, and good performance matching with skin glass, and is important for improving fiber coupling technology and efficient and stable operation of micro-light imaging devices.

Description

Technical Field

[0001] This invention relates to the field of glass manufacturing technology, and in particular to high refractive index core glass for fiber cones, its preparation method and application. Background Technology

[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] A fiber optic cone is a tapered glass fiber imaging device capable of magnifying or reducing two-dimensional images. Its characteristics include high resolution, high coupling efficiency, concentrated light energy, and excellent stability and reliability, making it a core component for achieving lightweight, miniaturized, and digitized images in low-light imaging devices. Currently, this device is widely used in the optical coupling of ICCDs and low-light image intensifiers, and has significant application value in fields such as national defense and scientific research.

[0004] Fiber optic cones are typically made of a composite of three glass materials: a core, a sheath, and an absorption layer. However, current technologies still struggle to achieve a good match between the core glass and the sheath glass in key parameters such as refractive index, coefficient of linear thermal expansion, anti-crystallization properties, and transmittance. This technological limitation affects their performance in low-light image intensifier coupling and low-light night vision image digitization, and also restricts their further application in fields with high requirements for image quality and system stability, such as medical imaging and environmental detection.

[0005] Existing core glass, ordinary optical glass BK7, has a refractive index of approximately 1.51, or low-lead glass with a refractive index less than 1.8, which is insufficient to meet the requirements of high numerical aperture (NA > 0.4), resulting in low fiber optic cone coupling efficiency (< 80%). High-refractive-index components (such as lead oxide and titanium dioxide) are susceptible to process fluctuations, leading to uneven refractive index distribution (± 0.02 deviation). In recent years, traditional core glass has revealed deficiencies in environmental compliance, such as glass containing lead (PbO), cadmium (CdO), or arsenic (As2O3); lead-free alternatives (such as Bi2O3) are expensive and exhibit a strong tendency for crystallization. Simultaneously, the softening point of high-refractive-index glass often does not match that of the outer glass, leading to interface cracking during fiber drawing and severely impacting product yield. Furthermore, high-refractive-index glass is typically accompanied by high dispersion characteristics (Abbe number < 30), introducing chromatic aberration during image transmission and reducing the imaging reliability and performance of fiber optic cones in precision optical instruments such as low-light night vision devices. Therefore, developing new glass materials that combine environmental compliance, good process compatibility, and low dispersion characteristics has become a key issue that urgently needs to be addressed in this field. Summary of the Invention

[0006] In view of this, the present invention provides a high refractive index core glass for fiber light cones, a method for preparing the same, and its application.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a high refractive index core glass for fiber optic cones, comprising or composed of the following components in molar percentage: SiO2 18.2-25%, H3BO3 38-45%, BaCO3 15-20%, TiO2 6-10%, La2O3 4.1-6%, SrCO3 2-3.6%, CaCO3 0.2-1.1%, Al(OH)3 0.2-1%, Y2O3 0.3-1.2%, Nb2O5 1.7-2.4%, and Sb2O3 0.1-0.6%.

[0008] Furthermore, the ratio of H3BO3 content to SiO2 content (H3BO3 / SiO2) is greater than 1.5 and less than 2.2.

[0009] Furthermore, the sum of BaCO3 and CaCO3 content is greater than 15.2%, the sum of SrCO3 and CaCO3 content is greater than 2.2% and less than 4.5%, and the sum of BaCO3, CaCO3 and SrCO3 is greater than 17.2% and less than 24.5%.

[0010] In embodiments of the present invention, silicon dioxide (SiO2) is the network forging body of the glass. Its silicon-oxygen tetrahedra [SiO4] are connected by covalent bonds to form a three-dimensional network structure, constituting the basic framework of the glass. This ensures the chemical stability and thermodynamic properties of the glass and prevents crystallization or phase separation caused by excessive introduction of high-refractive-index components. In terms of process performance optimization, silicon dioxide can adjust the viscosity of the glass melt and improve high-temperature forming performance. In embodiments of the present invention, the SiO2 content is 18.2-25% by molar percentage. In some embodiments of the present invention, the SiO2 content may be further selected from the following content ranges or any value within the following content ranges: 18.2-25%, 18.2-24%, 18.2-23%, 18.2-22%, 18.2-21%, 18.1-20.1%, 18.2-20.2%, 18.3-20.3%, 18.4-20.4%, 18.5-20.5%, 19.9-24.9%, 19.8-24.8%, 19.7-24.7%, 19.6-24.6%, 19.5-24.5%, 19.4-24.4%, 20.1-22.1%, 20.2-22.2%, 20.3-22.3%, etc.

[0011] In embodiments of this invention, boric acid (H3BO3) is a glass forging agent that can form glass on its own. It improves a range of glass properties and has good fluxing properties. In silicate glasses, boric acid breaks down the silicon-oxygen network (SiO4 tetrahedra) to form a more fluid BO3 trigonal structure, reducing high-temperature viscosity. However, boron anomalies exist. When the H3BO3 content exceeds a certain proportion, boron may transform from tricoordinate (BO3) to tetracoordinate (BO4), leading to nonlinear changes in properties and potentially causing phase separation or crystallization. Therefore, the boric acid content needs to be strictly controlled. In this invention, the H3BO3 content, by molar percentage, is 38-45%. In some embodiments of the present invention, the content of H3BO3 may be further selected from the following content ranges or any value within the following content ranges: 38-45%, 38-44%, 38-43%, 38-42%, 38-41%, 38-40%, 38-39%, 38-39.1%, 38-39.2%, 38-39.3%, 38-39.4%, 38-39.5%, 38-39.6%, 38-39.7%, 38-39.8%, 38-39.9%, 38.1-44.1%, 38.2-44.2%, 38.3-44.3%, 38.4-44.4%, 38.5-44.5%, 38.6-44.6%, 38.7-44.7%, 38.8-44.8%, 38.9-44.9%, etc.

[0012] In the embodiments of this invention, barium carbonate (BaCO3) is the network exogenous substance. Among the alkali metals, barium has the largest atomic number, the largest ionic radius, and the strongest basicity, which determines its series of properties such as improving the refractive index, dispersion, and fluxing properties of glass. Simultaneously, barium carbonate can reduce the network porosity of the glass, effectively reducing the erosion by water or acids and alkalis, and improving water resistance and corrosion resistance. At high temperatures, barium carbonate decomposes into barium oxide and carbon dioxide, which can reduce the viscosity of the glass melt. However, when its content is too high, the glass network structure becomes excessively loose, leading to a decrease in chemical stability. Therefore, this invention limits the upper limit to 20%, and mandates the introduction of a total of 2.2-4.5% CaCO3 and SrCO3. These high-field-strength ions can repair the network bond breakage caused by the introduction of BaCO3, significantly improving the hardness and water resistance of the glass. When the total alkaline earth metal content is below 18.6%, the network modification is insufficient, making glass melting difficult and the refractive index not meeting the standard; when it is above 24.5%, the glass phase transformation tendency increases, easily leading to devitrification or barium salt precipitation. Therefore, in this invention, the content of BaCO3 is 15-20% by mole percentage, and the sum of BaCO3, CaCO3 and SrCO3 is greater than 18.6% and less than 24.5%.

[0013] In this invention, the BaCO3 content, by molar percentage, is 15-20%. In some embodiments of this invention, the BaCO3 content may be further selected from the following content ranges or any value within the following content ranges: 15-20%, 15-19%, 15-18%, 15-17%, 15-16%, 15.1-19.1%, 15.1-19.2%, 15.1-19.3%, 15.1-19.4%, 15.1-19.5%, 15.1-19.6%. %, 15.1-19.7%, 15.1-19.8%, 15.1-19.9%, 16-17%, 16-18%, 16.1-17.1%, 16.2-17.2%, 16.3-17.3%, 16.4-17.4%, 16.5-17.5%, 16.6-17.6%, 16.7-17.7%, 16.8-17.8%, 16.9-17.9%, etc.

[0014] In embodiments of the present invention, titanium oxide (TiO2) is the network exogenous ion. In silicate glasses, titanium is often present as TiO2. 4+ In its octahedral state, titanium oxide (TiO2) can improve the refractive index, density, and resistivity of glass. Within a certain range, TiO2 can reduce the coefficient of thermal expansion and improve the acid resistance of glass. In this invention, the content of TiO2 is 6-10% by molar percentage. In some embodiments of the present invention, the TiO2 content may be further selected from the following content ranges or any value within the following content ranges: 6-10%, 7-9%, 6.1-7.1%, 6.2-7.2%, 6.3-7.3%, 6.4-7.4%, 6.5-7.5%, 6.6-7.6%, 6.7-7.7%, 6.8-7.8%, 6.9-7.9%, 8-9%, 8.1-9.1%, 8.2-9.2%, 8.3-9.3%, 8.4-9.4%, 8.5-9.5%, 8.6-9.6%, 8.7-9.7%, 8.8-9.8%, 8.9-9.9%, etc.

[0015] In the embodiments of the present invention, lanthanum oxide (La₂O₃) plays an important role in glass. Lanthanum oxide belongs to rare earth oxides and plays a key role in improving the refractive index of glass. Lanthanum in glass is generally in the form of La. 3+ The state exists because La 3+With its large radius and high coordination number, lanthanum oxide is not a glass-forming agent and cannot enter the network, instead residing in the network voids. Therefore, glasses containing lanthanum oxide have a compact structure and a high refractive index. Appropriate introduction of lanthanum oxide can effectively improve the chemical stability of the glass, reduce its coefficient of thermal expansion, and improve its processing properties. In this invention, the content of La2O3 is 4-6% by molar percentage. In some embodiments of the present invention, the content of La2O3 may be further selected from the following content ranges or any value within the following content ranges: 4-6%, 4-5%, 4.1-4.9%, 4.1-4.8%, 4.1-4.7%, 4.1-4.6%, 4.1-4.5%, 4.1-4.4%, 4.1-4.3%, 4.1-4.2%, 5.1-6%, 5.1-5.9%, 5.1-5.8%, 5.1-5.7%, 5.1-5.6%, 5.1-5.5%, 5.1-5.4%, 5.1-5.3%, 5.1-5.2%, etc.

[0016] In an embodiment of the present invention, strontium carbonate (SrCO3) is a network exooxide. SrCO3 decomposes at high temperatures into strontium oxide and carbon dioxide. 2+ As a divalent alkaline earth metal ion, Sr has a relatively large ionic radius (approximately 118 pm) and its outer electrons are weakly bound to the atomic nucleus, resulting in high polarizability. 2+ When Sr fills the gaps in the silica-oxygen network of glass as an outer layer, it significantly enhances the overall polarization ability of the glass, thereby increasing its refractive index. 2+ Sr has a strong binding force with oxygen ions in the glass network, which can reduce the ion dissolution when the glass surface is corroded by water or acid (such as avoiding "weathering" caused by alkali metal ions); at the same time, Sr 2+ The filling effect of SrCO3 can improve the density and structural compactness of glass, enhance its hardness and impact resistance, and extend its service life. In this invention, the content of SrCO3 is 2-4% by molar percentage. In some embodiments of this invention, the content of SrCO3 may be further selected from the following content ranges or any value within the following content ranges: 2-4%, 2.1-3.1%, 2.2-3.2%, 2.3-3.3%, 2.4-3.4%, 2.5-3.5%, 2.6-3.6%, 2.7-3.7%, 2.8-3.8%, 2.9-3.9%, 2.1-4%, 2.2-4%, 2.3-4%, 2.4-4%, 2.5-4%, 2.6-4%, 2.7-4%, 2.8-4%, 2.9-4%, 3-4%, etc.

[0017] In embodiments of the present invention, calcium carbonate (CaCO3) alkaline earth metal oxides are typical network exooxides, with cations Ca... 2+This process disrupts the [SiO4] tetrahedral network structure in silicate glass, forming non-bridging oxygen (NBO), thereby lowering the melting temperature and adjusting the viscosity. In this invention, the CaCO3 content is 0.2-1.1% by molar percentage. In some embodiments of this invention, the CaCO3 content may be further selected from the following content ranges or any value within the following content ranges: 0.2-1.1%, 0.3-1%, 0.4-0.9%, 0.5-0.8%, 0.6-0.7%, etc.

[0018] In embodiments of the present invention, aluminum hydroxide (Al(OH)3) is a glass intermediate. Boric acid is typically used in conjunction with aluminum hydroxide (Al(OH)3) and sodium carbonate (Na2CO3) to balance performance. Aluminum hydroxide decomposes into aluminum oxide at high temperature. 3+ Al(OH)3 typically exists in the form of tetracoordinate [AlO4], replacing some [SiO4] in the network structure, enhancing the stability of the glass network, and reducing the crystallization tendency of the boron-oxygen network in the glass. Furthermore, aluminum-oxygen tetrahedra have a larger volume than silicon-oxygen tetrahedra, resulting in a looser structure with larger voids, which facilitates the movement of alkali metal ions. In this invention, the content of Al(OH)3 is 0.2-1% by molar percentage. In some embodiments of this invention, the content of Al(OH)3 may be further selected from the following content ranges or any value within the following content ranges: 0.2-1%, 0.3-1%, 0.4-1%, 0.5-1%, 0.6-1%, 0.7-1%, 0.8-1%, 0.9-1%, etc.

[0019] In embodiments of the present invention, yttrium oxide (Y₂O₃) is a network intermediate oxide. It does not form a glass network itself, but it can be embedded in the voids of the silicon-oxygen network (SiO₂), strengthening the glass structure and making the glass network more compact and stable. Yttrium ions (Y₂O₃) 3+ Y₂O₃ possesses high ionic polarization and field strength. When introduced into a glass network (typically a silicate or borate system), it increases the glass's density and overall polarizability, thereby significantly improving the glass's refractive index. In this invention, the content of Y₂O₃, by molar percentage, is 0.3-1.2%. In some embodiments of this invention, the content of Y₂O₃ may be further selected from the following content ranges or any value within the following content ranges: 0.3-1.2%, 0.3-1.1%, 0.3-1%, 0.3-0.9%, 0.3-0.8%, 0.3-0.7%, 0.3-0.6%, 0.3-0.5%, 0.3-0.4%, 0.6-1%, 0.7-1%, 0.8-1%, 0.9-1%, 0.9-1.1%, 0.9-1.2%, etc.

[0020] In an embodiment of the present invention, niobium ions (Nb ions) in niobium pentoxide... 5+ Nb possesses high ionic polarizability and high field strength. When introduced into glass networks (such as silicate and borate networks), it greatly increases the density and electronic polarizability of the glass, thereby very effectively improving the refractive index of the glass. 5+ Ions can enter the voids of the glass network and strengthen the network structure. The Nb-O bond strength is very high, making the glass network denser and more stable; therefore, niobium pentoxide is a high-performance optical modifier. In this invention, the Nb₂O₅ content is 1.7-2.4% by molar percentage. In some embodiments of this invention, the Nb₂O₅ content may be further selected from the following content ranges or any value within the following content ranges: 1.7-2.4%, 1.7-2.3%, 1.7-2.2%, 1.7-2.1%, 1.7-2.0%, 1.8-2.4%, 1.8-2.3%, 1.8-2.2%, 1.8-2.1%, 1.8-2.0%, 1.8-1.9%, etc.

[0021] In embodiments of the present invention, antimony trioxide (Sb₂O₃) can be used as a clarifying agent. During the glass melting process, the reaction of raw materials generates bubbles (such as CO₂, O₂, N₂, etc.), affecting the transparency of the glass. Sb₂O₃ decomposes at high temperatures and releases oxygen (2Sb₂O₃→2Sb₂O₄+O₂↑). The bubbles expand in volume and increase buoyancy under the influence of oxygen, making them more likely to rise to the surface of the molten glass and burst and escape. Compared to traditional clarifying agents (such as arsenic compounds), Sb₂O₃ has lower toxicity and better stability at high temperatures, making it particularly suitable for high-temperature molten glass (such as optical glass and borosilicate glass). In this invention, the content of Sb₂O₃ is 0.1-0.6% by molar percentage. In some embodiments of the present invention, the content of Sb₂O₃ may be further selected from the following content ranges or any value within the following content ranges: 0.1-0.6%, 0.1-0.5%, 0.1-0.4%, 0.1-0.3%, 0.1-0.2%, etc.

[0022] The various specific technical features described in the above embodiments of the present invention can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0023] Unless otherwise specified, the numerical range described in this invention includes all values ​​within this range, and also includes the range value formed by any two values ​​within this range. For example, 1.1-2% includes all values ​​between 1.1% and 2%, and also includes the range value (1.12-1.999%) formed by any two values ​​within this range (e.g., 1.12% and 1.999%). Different values ​​of the same indicator appearing in all embodiments of this invention can be arbitrarily combined to form a range value.

[0024] In a second aspect, the present invention provides a method for preparing the high refractive index core glass for fiber optic cones as described in the first aspect, comprising the following steps: The raw materials are mixed evenly according to the proportions, melted at high temperature with auxiliary stirring and clarification, cooled and cast into shape, and annealed to obtain optoelectronic glass preforms; The optoelectronic glass blank is prepared into a glass rod, and then piped, drawn into a single wire, arranged into a first rod, drawn into a first multi-wire, arranged into a second rod, and drawn into a second multi-wire to obtain the final product.

[0025] In some embodiments of the present invention, the high-temperature melting temperature is 1550-1600 °C. In some embodiments of the present invention, during the forming process, the glass melt is cooled to 1400-1450 °C for casting, and the mold temperature for casting is 480-500 °C. In some embodiments of the present invention, the annealing temperature is 500-550 °C. In some embodiments of the present invention, the method of uniform mixing is assisted by bubbling clarification. Based on the components disclosed in the first aspect of the present invention, the glass material prepared within this temperature range possesses stable properties, including but not limited to high refractive index, good thermal expansion properties, and good processability.

[0026] In some embodiments of the present invention, the raw materials may also be selected from the following materials as needed: quartz sand, boric acid (or boron oxide), barium carbonate (barium nitrate), lanthanum oxide, strontium carbonate (strontium oxide), calcium carbonate (or calcium oxide), and antimony oxide.

[0027] In some embodiments of the present invention, the piping steps are as follows: the glass rod and the glass tube are wound with iron wire, then the glass rod is inserted into the glass tube, the position is adjusted so that the lower end of the glass tube protrudes about 40 mm more than the lower end of the glass rod, and then the upper end is sealed with PTFE tape. The steps for drawing monofilaments are as follows: The pre-wound glass tube and rod are suspended in the drawing machine, and a furnace lid of appropriate size is fitted (the furnace lid diameter is 0.5-1.5 mm larger than the rod, generally 1 mm larger). A vacuum device is installed above the glass tube and rod. From top to bottom, the drawing machine consists of a support frame and vacuum device, a resistance furnace, a feeding port, a wire diameter gauge, rollers, a cutter, and a monofilament collection tray. During the drawing process, the furnace temperature is initially set to 900℃, and the material is fed at a speed of 7 mm / min. After feeding 50 mm, feeding is paused to allow the material head to melt. Once the material head melts, the temperature is immediately lowered to the drawing temperature, and feeding resumes. Vacuuming begins when the material has fed approximately 80 mm.

[0028] The steps for assembling a primary rod are as follows: Wipe the drawn monofilaments with alcohol and let them air dry to prepare for assembling the primary rod. Each primary rod has 5 monofilaments at its bottom edge, and each rod requires 61 monofilaments. Simultaneously, wrap the rod with aluminum foil and PTFE tape to prevent air leakage during the vacuuming process. After wrapping, insert black gap wires into the gaps to absorb stray light and ensure the normal performance of the imaging element.

[0029] The steps for drawing a single multifilament are as follows: Wrap a vacuum iron head around the upper end of the primary rod and suspend it on the multifilament drawing machine. After the wire is drawn, adjust the drawing temperature to make the target wire diameter 1.300 mm ± 0.005 mm and stabilize the wire output temperature at 900 ℃. There is no wire deviation during the drawing process, and the structure of the single wire and the gap wire can be observed in the cross section of the single multifilament.

[0030] The process of arranging the second rod and drawing the second multifilament is the same as that of arranging the first rod and drawing the first multifilament. It is necessary to strictly control the drawing speed and temperature to ensure that the core material and the sheath material are perfectly fused at high temperature without producing bubbles, defects or mutual penetration, and to maintain a smooth and clear interface. The thermal properties of the core material and the sheath material must be highly matched. The internal stress generated during the cooling process will cause the light cone to crack or its performance to decline.

[0031] Thirdly, the present invention provides the application of the high refractive index core glass for fiber cones described in the first aspect in the fabrication of optical elements or optical instruments.

[0032] Furthermore, the optical element or optical instrument includes optical glass, fiber taper, and fiber optic panel.

[0033] The fiber core glass described in this invention has excellent optical transmittance and high refractive index, as well as suitable thermal expansion coefficient and softening temperature performance. It has good process adaptability in the drawing and hot pressing processes. For example, the fiber core glass prepared with it for fiber cones still maintains high transmittance and anti-crystallization performance during drawing, hot pressing and cold processing. Its optical and physicochemical properties hardly change, and it can be well matched with the skin glass.

[0034] Compared with the prior art, the present invention has achieved the following beneficial effects: This invention provides a fiber core glass with a high refractive index, environmental friendliness, and a thermal expansion coefficient matching that of the outer glass. The glass has a refractive index ≥ 1.81 and a thermal expansion coefficient of (85-89) × 10⁻⁶. -7 With a glass transition temperature ≥ 550 ℃, it has good thermal processing performance and can be well matched with the performance of the glass substrate, which is of great significance for improving the efficient and stable operation of fiber optic coupling technology and low-light imaging devices. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0036] Figure 1 The internal transmittance (@310-1400 nm) of the glass materials of Examples 1-6 and Comparative Examples 1-6 is shown in the comparison graph.

[0037] Figure 2 The refractive indices (n) of the glass materials of Examples 1-6 and Comparative Examples 1-6 are shown. D Comparison chart.

[0038] Figure 3 The linear thermal expansion coefficients α of the glass materials of Examples 1-6 and Comparative Examples 1-6 are shown. 30 / 300 [10 -7 [ / ℃] Comparison chart. Detailed Implementation

[0039] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0040] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0041] Example 1 The high-refractive-index optoelectronic glass material of this embodiment is prepared from the following raw materials by molar percentage: 20% SiO2, 42.9% H3BO3, 18% BaCO3, 7.2% TiO2, 4.1% La2O3, 3.4% SrCO3, 1.1% CaCO3, 0.3% Al(OH)3, 0.4% Y2O3, 2.1% Nb2O5, and 0.5% Sb2O3, as shown in Table 1. The specific preparation steps are as follows: (1) Mix the raw materials in proportion, melt them at 1600 ℃, stir and clarify them with auxiliary stirring, cast them at 1450 ℃ (mold temperature 500 ℃), and anneal them at 550 ℃ to obtain glass blanks.

[0042] (2) The glass blank obtained in step (1) is mechanically processed into a round rod shape, wherein the mechanical processing includes cutting, grinding and polishing; then the pipe drawing and rod arrangement are carried out, wherein the furnace temperature of the drawing tower is 900 ℃, the feeding speed is 7 mm / min, and the target wire diameter is 1.300 mm ± 0.005.

[0043] Piping steps: Wrap the glass rod and glass tube with iron wire, then insert the glass rod into the glass tube, adjust the position so that the lower end of the glass tube protrudes about 40 mm more than the lower end of the glass rod, and then seal the upper end with PTFE tape. The steps for drawing monofilaments are as follows: The pre-wound glass tube and rod are suspended in the drawing machine, and a furnace lid of appropriate size is fitted (the furnace lid diameter is 0.5-1.5 mm larger than the rod, generally 1 mm larger). A vacuum device is installed above the glass tube and rod. From top to bottom, the drawing machine consists of a support frame and vacuum device, a resistance furnace, a feeding port, a wire diameter gauge, rollers, a cutter, and a monofilament collection tray. During the drawing process, the furnace temperature is initially set to 900℃, and the material is fed at a speed of 7 mm / min. After feeding 50 mm, feeding is paused to allow the material head to melt. Once the material head melts, the temperature is immediately lowered to the drawing temperature, and feeding resumes. Vacuuming begins when the material has fed approximately 80 mm.

[0044] The steps for assembling a primary rod are as follows: Wipe the drawn monofilaments with alcohol and let them air dry to prepare for assembling the primary rod. Each primary rod has 5 monofilaments at its bottom edge, and each rod requires 61 monofilaments. Simultaneously, wrap the rod with aluminum foil and PTFE tape to prevent air leakage during the vacuuming process. After wrapping, insert black gap wires into the gaps to absorb stray light and ensure the normal performance of the imaging element.

[0045] The steps for drawing a single multifilament are as follows: Wrap a vacuum iron head around the upper end of the primary rod and suspend it on the multifilament drawing machine. After the wire is drawn, adjust the drawing temperature to make the target wire diameter 1.300 mm ± 0.005 mm and stabilize the wire output temperature at 900 ℃. There is no wire deviation during the drawing process, and the structure of the single wire and the gap wire can be observed in the cross section of the single multifilament.

[0046] The process of arranging the second rod and drawing the second multifilament is the same as that of arranging the first rod and drawing the first multifilament. It is necessary to strictly control the drawing speed and temperature to ensure that the core material and the sheath material are perfectly fused at high temperature without producing bubbles, defects or mutual penetration, and to maintain a smooth and clear interface. The thermal properties of the core material and the sheath material must be highly matched. The internal stress generated during the cooling process will cause the light cone to crack or its performance to decline.

[0047] Example 2 The high-refractive-index optoelectronic glass material of this embodiment is prepared from the following raw materials in molar percentage: 24.9% SiO2, 39% H3BO3, 17% BaCO3, 8.1% TiO2, 5% La2O3, 2.8% SrCO3, 0.6% CaCO3, 0.5% Al(OH)3, 0.3% Y2O3, 1.7% Nb2O5, and 0.1% Sb2O3, as shown in Table 1. The specific preparation steps are the same as in Example 1.

[0048] Example 3 The high-refractive-index optoelectronic glass material of this embodiment is prepared from the following raw materials in molar percentage: 18.2% SiO2, 38% H3BO3, 20% BaCO3, 10% TiO2, 5.2% La2O3, 3.6% SrCO3, 0.9% CaCO3, 0.4% Al(OH)3, 1.1% Y2O3, 2.4% Nb2O5, and 0.2% Sb2O3, as shown in Table 1. The specific preparation steps are the same as in Example 1.

[0049] Example 4 The high-refractive-index optoelectronic glass material of this embodiment is prepared from the following raw materials by molar percentage: 19.9% ​​SiO2, 40.4% H3BO3, 17.5% BaCO3, 8.9% TiO2, 5.6% La2O3, 2.9% SrCO3, 0.7% CaCO3, 0.6% Al(OH)3, 1% Y2O3, 2.1% Nb2O5, and 0.4% Sb2O3, as shown in Table 1. The specific preparation steps are the same as in Example 1.

[0050] Example 5 The high-refractive-index optoelectronic glass material of this embodiment is prepared from the following raw materials in molar percentage: 25% SiO2, 45% H3BO3, 15% BaCO3, 6% TiO2, 4.5% La2O3, 2% SrCO3, 0.2% CaCO3, 0.2% Al(OH)3, 0.3% Y2O3, 1.7% Nb2O5, and 0.1% Sb2O3, as shown in Table 1. The specific preparation steps are the same as in Example 1.

[0051] Example 6 The high-refractive-index optoelectronic glass material of this embodiment is prepared from the following raw materials in molar percentage: 21% SiO2, 40.2% H3BO3, 15.9% BaCO3, 9% TiO2, 6% La2O3, 2.2% SrCO3, 0.5% CaCO3, 1% Al(OH)3, 1.2% Y2O3, 2.4% Nb2O5, and 0.6% Sb2O3, as shown in Table 1. The specific preparation steps are the same as in Example 1.

[0052] Table 1. Composition of glass samples from Examples 1-6

[0053] Comparative Example 1 The photoelectric glass material of this comparative example, by molar percentage, consists of the following components: 30% SiO2, 39.6% H3BO3, 19.0% BaCO3, 3.5% TiO2, 4.2% La2O3, 1% SrCO3, 0.8% CaCO3, 0.4% Al(OH)3, 0.5% Y2O3, 0.6% Nb2O5, and 0.4% Sb2O3, as shown in Table 2. Its specific preparation steps are the same as in Example 1.

[0054] Comparative Example 2 The optoelectronic glass material of this comparative example, by molar percentage, consists of the following components: 32% SiO2, 36.3% H3BO3, 17.8% BaCO3, 4.6% TiO2, 5.5% La2O3, 1% SrCO3, 0.5% CaCO3, 0.5% Al(OH)3, 0.4% Y2O3, 1.1% Nb2O5, and 0.3% Sb2O3, as shown in Table 2. Its specific preparation steps are the same as in Example 1.

[0055] Comparative Example 3 The optoelectronic glass material of this comparative example, by molar percentage, consists of the following components: 34% SiO2, 26.9% H3BO3, 21.5% BaCO3, 3% TiO2, 4.6% La2O3, 6% SrCO3, 1.5% CaCO3, 0.6% Al(OH)3, 0.8% Y2O3, 0.8% Nb2O5, and 0.3% Sb2O3, as shown in Table 2. The specific preparation steps are the same as in Example 1.

[0056] Comparative Example 4 The optoelectronic glass material of this comparative example, by molar percentage, consists of the following components: 35% SiO2, 30.7% H3BO3, 18.9% BaCO3, 2.8% TiO2, 5.3% La2O3, 4% SrCO3, 1% CaCO3, 0.4% Al(OH)3, 0.7% Y2O3, 0.7% Nb2O5, and 0.5% Sb2O3, as shown in Table 2. Its specific preparation steps are the same as in Example 1.

[0057] Comparative Example 5 The optoelectronic glass material of this comparative example, by molar percentage, consists of the following components: 28% SiO2, 43.7% H3BO3, 16.9% BaCO3, 2.5% TiO2, 4.4% La2O3, 2% SrCO3, 0.8% CaCO3, 0.3% Al(OH)3, 0.6% Y2O3, 0.6% Nb2O5, and 0.2% Sb2O3, as shown in Table 2. Its specific preparation steps are the same as in Example 1.

[0058] Comparative Example 6 The optoelectronic glass material of this comparative example, by molar percentage, consists of the following components: 25% SiO2, 42.8% H3BO3, 18.1% BaCO3, 3.8% TiO2, 4.1% La2O3, 2% SrCO3, 1.2% CaCO3, 0.8% Al(OH)3, 0.9% Y2O3, 0.7% Nb2O5, and 0.6% Sb2O3, as shown in Table 2. Its specific preparation steps are the same as in Example 1.

[0059] Table 2. Composition of glass samples from Comparative Examples 1-6

[0060] The performance of the optoelectronic glass materials prepared in Examples 1-6 and Comparative Examples 1-6 was tested using the following methods (standard): The transmittance of glass samples was determined using a Shimadzu UV-Vis spectrophotometer (UV~3600 Plus). The test wavelength range was 310 nm–1400 nm. The glass samples were optically polished, and the sample thicknesses were 1 mm and 2 mm. The measurement wavelength range was 185–3300 nm; the resolution was 0.1 nm; multiple spectral bandwidths were available; the light source consisted of a 50 W halogen lamp and a deuterium lamp with automatic switching; and the measurement method was a dual-beam measurement mode (GB / T 7962.12-2010).

[0061] The softening point temperature of glass samples was tested using an Orton Model PPV-1000 / 1200 plate viscometer. Sample preparation: The glass sample was ground into a cylindrical strip of Φ6×6 mm, with both ends parallel. The sample was placed between top and bottom discs made of a heat-resistant metal alloy, 44 mm in diameter and 6 mm thick. The top metal disc was attached to the bottom of the probe bar. Two very thin platinum films (40 mm in diameter and 0.001 inch thick) were placed between the sample and the top and bottom discs for easy sampling and sample placement (ASTM C-1351M).

[0062] The coefficient of thermal expansion was tested using a DIL 402 Expedis Classic thermal expansion meter. The nitrogen pressure of the instrument was adjusted to 0.06 MPa. On the temperature program setting page, the reset mode was selected at the softening point detection. The sample shrinkage was 0.1%. After the test, the furnace could only be opened when the temperature dropped below 100 ℃ to avoid damage to the equipment due to a sudden drop in temperature.

[0063] The test results are shown in Tables 3-4 and Figures 1-3 As shown.

[0064] Table 3 Performance test results of glass samples from Examples 1-6 and Comparative Examples 1-6

[0065] Table 4 Performance test results of glass samples from Comparative Examples 1-6

[0066] As shown in Table 3, the glass materials prepared in each embodiment all exhibit high spectral transmittance, excellent intraspectral transmittance, and a minimum intraspectral transmittance in the effective region ≥ 99.80% (@310-1400 nm). They also possess a high refractive index ≥ 1.78, which matches well with the refractive index of the glass substrate. Furthermore, the coefficient of thermal expansion is 85.6-88.3 (×10⁻⁶). -7 The glass exhibits excellent thermal processing properties due to its temperature (°C). The properties of the glass material of this invention, such as spectral transmittance, refractive index, coefficient of linear expansion, glass transition temperature, and glass softening temperature, are largely unaffected by mechanical processing. In summary, these superior properties enable the glass material of this invention to play a crucial role in fiber optic imaging fields, such as military, medical imaging, and environmental monitoring.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-refractive-index core glass for fiber optic cones, characterized in that, It contains or is composed of the following components by molar percentage: SiO2 18.2-25%, H3BO3 38-45%, BaCO3 15-20%, TiO2 6-10%, La2O3 4.1-6%, SrCO3 2-3.6%, CaCO3 0.2-1.1%, Al(OH)3 0.2-1%, Y2O3 0.3-1.2%, Nb2O5 1.7-2.4%, and Sb2O3 0.1-0.6%.

2. The fiber-core glass as described in claim 1, characterized in that, The ratio of H3BO3 content to SiO2 content is greater than 1.5 and less than 2.2; And / or, the sum of BaCO3 and CaCO3 content is greater than 15.2%, the sum of SrCO3 and CaCO3 content is greater than 2.2% and less than 4.5%, and the sum of BaCO3, CaCO3 and SrCO3 is greater than 17.2% and less than 24.5%.

3. The method for preparing high-refractive-index core glass for fiber optic cones as described in claim 1, characterized in that, Includes the following steps: The raw materials are mixed evenly according to the proportions, melted at high temperature with auxiliary stirring and clarification, cooled and cast into shape, and annealed to obtain optoelectronic glass preforms. The optoelectronic glass blank is prepared into a glass rod, and then piped, drawn into a single wire, arranged into a first rod, drawn into a first multi-wire, arranged into a second rod, and drawn into a second multi-wire to obtain the final product.

4. The preparation method according to claim 3, characterized in that, The high-temperature melting temperature is 1550-1600 ℃; and / or, the glass melt is cooled to 1400-1450 ℃ for casting.

5. The preparation method according to claim 3, characterized in that, The temperature of the mold used for casting is 480-500 ℃.

6. The preparation method according to claim 3, characterized in that, The annealing temperature is 500-550 ℃.

7. The preparation method according to claim 3, characterized in that, During the drawing of monofilaments, the temperature is 900 ℃ and the feeding speed is 6-8 mm / min.

8. The preparation method according to claim 3, characterized in that, The target wire diameter is 1.300mm ± 0.

005.

9. The application of the high refractive index core glass for fiber cones as described in claim 1 in the fabrication of optical elements or optical instruments.

10. The application as described in claim 9, characterized in that, The optical elements or instruments include optical glass, fiber tapers, and fiber optic panels.

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