Optical fiber image guide glass, method for preparing the same, and use thereof

Abstract

The application relates to a light-absorbing material glass for an optical fiber image transmission element and a preparation method and application thereof. The light-absorbing material glass for the optical fiber image transmission element comprises the following components in mole percentage: 68.0-78.0% of SiO2, 1.0-9.0% of Al2O3, 2.0-10.0% of B2O3, 1.0-10.0% of Na2O, 3.0-10.0% of K2O, 0.1-1.5% of MgO, 0.1-3.0% of CaO, 0.1-0.5% of SrO, 0.1-1.5% of NiO, 0.1-1.2% of Co2O3, 0.1-0.8% of MnO2 and 0.1-0.8% of Nd2O3. The light-absorbing material glass for the optical fiber image transmission element can solve the black-and-white display compatibility problem of the optical fiber image transmission element and a low-light-level image intensifier, and perfect black-and-white display compatibility with P45 fluorescent powder is realized.

Description

Technical Field

[0001] This invention relates to the field of glass material manufacturing, and in particular to a light-absorbing glass for optical fiber imaging elements and its preparation method. Background Technology

[0002] With the continuous development of optical imaging technology, low-light image intensifiers have been widely used in military, security, and field exploration fields. In low-light image intensifier systems, fiber optic imaging elements play a crucial role, responsible for the efficient transmission and accurate imaging of optical images, and their performance directly affects the quality of the final image.

[0003] Since low-light image intensifiers are used in direct-view optical systems, the emission spectrum of the phosphor screen, which serves as the image output end, should have good human eye adaptability. In an image intensifier, the phosphor's role is to convert the electronic image enhanced by the microchannel plate into an optical image. However, commonly used phosphors such as P20 and P43 have peak wavelengths of 540-550nm and emit yellow-green light. While green light has moderate absorption and reflection, and the human nervous system, cerebral cortex, and retinal tissue are relatively sensitive to green, this yellow-green wavelength, although most sensitive to human vision, is still a significant factor. However, prolonged viewing can cause eye strain and fatigue. The most comfortable viewing experience for the human eye is achieved with P45 phosphor, which displays black and white light, offering strong visual contrast and clearer detail. Furthermore, the broad spectrum of P45 phosphor reduces eye fatigue during focusing. However, P45 phosphor has relatively low screen efficiency and short persistence. To achieve high screen efficiency, a suitable fiber optic imaging element must be selected. This requires good compatibility between the light-absorbing glass material used in the fiber optic imaging element and the P45 phosphor to produce a clear and stable image. However, existing light-absorbing glass materials for fiber optic imaging elements have significant shortcomings in compatibility with P45 phosphor. On the one hand, the light absorption characteristics of traditional light-absorbing glass materials cannot be precisely matched with the emission spectrum of P45 phosphor, leading to problems such as color deviation, insufficient sharpness, decreased contrast, and halo effects during image display, severely affecting the clarity and visual effect of the low-light image intensifier image. On the other hand, the poor physicochemical stability of light-absorbing glass materials and their poor compatibility with the core-sheath glass materials used in fiber optic imaging elements limit the performance improvement of the entire fiber optic imaging element. The main reason for this is that existing light-absorbing materials cannot precisely control the light signal to perfectly match the display characteristics of the P45 phosphor used in monochrome displays.

[0004] Fiber optic imaging elements include optical fiber panels, fiber optic image inverters, and fiber optic cones. The imaging mechanism of fiber optic imaging elements utilizes the principle of total internal reflection of optical fibers. The optical fibers constituting the fiber optic imaging element are made by combining a low-refractive-index cladding glass tube, a high-refractive-index core glass rod, and light-absorbing glass filaments using a rod-tube bonding and vacuum drawing process, followed by hot-melt pressing. Because the optical fibers are completely and tightly fused together by the cladding glass, the close proximity of adjacent optical fibers leads to light leakage. For example, uneven temperature fields or uneven drawing forces during the manufacturing process may cause uneven wall thickness of the cladding glass tube, resulting in light penetration during total internal reflection and light leakage. Alternatively, defects or contaminants at the glass or cladding glass interface of the fiber optic fiber may disrupt the conditions for total internal reflection, causing light scattering. This scattered light entering adjacent optical fibers also causes light leakage, which is a crucial factor directly affecting the contrast, sharpness, and other imaging quality of fiber optic imaging elements. To address the challenges of light crosstalk and leakage between optical fibers in fiber optic imaging elements, a common approach is to fill the gaps between adjacent optical fibers with light-absorbing glass filaments to absorb stray light and reduce crosstalk. This method effectively eliminates stray light by drawing the light-absorbing glass into filaments and inserting them into the gaps between the arranged optical fibers. However, it doesn't completely eliminate light crosstalk; the key factor is the transmittance of the light-absorbing glass. The function of the light-absorbing glass is to absorb stray light penetrating the fiber sheath to achieve optical insulation and improve image contrast. Light-absorbing glass is an important type of optical glass, primarily used to absorb interfering stray light and improve the sharpness and contrast of fiber optic imaging elements. With the increasing application of monochrome image intensifiers, the requirements for fiber optic imaging elements are becoming more stringent. Therefore, the light-absorbing glass material must be able to precisely control the optical signal to match the display characteristics of the P45 phosphor in monochrome displays.

[0005] Therefore, developing a light-absorbing glass material for fiber optic imaging elements that is perfectly compatible with P45 phosphor monochrome displays, solving the compatibility problem between fiber optic imaging elements and low-light image intensifier monochrome displays, and improving low-light imaging quality has important practical significance and application value. Summary of the Invention

[0006] To address the aforementioned problems in the prior art, this invention provides a light-absorbing glass for fiber optic imaging elements. This light-absorbing glass can solve the compatibility problem between fiber optic imaging elements and micro-image intensifier monochrome displays, achieving perfect compatibility with P45 phosphor monochrome displays.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A composition of a light-absorbing glass for fiber optic imaging elements, comprising the following components in molar percentages:

[0009]

[0010] The present invention also provides a preferred technical solution, a composition of light-absorbing glass for optical fiber imaging elements, comprising the following components in molar percentage:

[0011]

[0012] The present invention also provides a more preferred technical solution, a composition of light-absorbing glass for optical fiber imaging elements, comprising the following components in molar percentage:

[0013]

[0014]

[0015] The total content of colorants NiO, Co2O3, MnO2, and Nd2O3 in the light-absorbing glass is no more than 2.0 mol.%. The total content of the light-absorbing colorants in this invention does not exceed 2.0 mol.%, which can effectively improve the transmittance in the ultraviolet band and reduce the transmittance in the visible light band.

[0016] This invention further provides a method for preparing a light-absorbing glass for an optical fiber imaging element using the aforementioned composition, comprising the following steps:

[0017] (1) Raw material preparation: Mix the raw materials evenly according to the proportion to obtain a raw material mixture;

[0018] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1500-1560℃ for 4-8 hours. After the raw material mixture melts, it is stirred 2-3 times, with a stirring speed of 150-180 rpm and a stirring time of 0.5-1 hour each time, to ensure that all components are fully and uniformly melted until a clear and homogeneous glass liquid is formed. Then, the material is discharged at 1420-1480℃ and cast into a mold to form the required glass, forming a preliminary glass structure. After the glass cools and solidifies, it is annealed to obtain a light-absorbing glass blank for optical fiber imaging elements. The annealing temperature is 560-600℃ and the annealing time is 24-36 hours.

[0019] (3) Blank processing: The light-absorbing glass blank after annealing and cooling is cut, ground and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements of the optical fiber imaging element and the optical matching requirements with P45 phosphor.

[0020] This invention further provides a light-absorbing glass for fiber optic imaging elements, prepared according to the aforementioned method. The light-absorbing glass for fiber optic imaging elements, with a thickness of 0.30±0.01 mm, exhibits a spectral transmittance >70% in the ultraviolet wavelength range of 300-400 nm and a spectral transmittance <2.0% in the visible light wavelength range of 580-670 nm; its coefficient of thermal expansion at 30-300℃ is (77±2)×10⁻⁶. －7 / ℃; no crystallization occurs when held at 850℃ for 6 hours.

[0021] The present invention also provides the application of light-absorbing glass for fiber optic imaging elements in low-light image intensifiers.

[0022] The present invention provides a light-absorbing glass for optical fiber imaging elements, which is suitable for use as a light-absorbing glass material for glass fibers when preparing optical fiber imaging elements. The optical fiber imaging elements include optical fiber panels, optical fiber image inverters, optical fiber tapers, etc.; the optical fiber imaging elements are used in micro-image intensifiers.

[0023] In the optical fiber imaging element light-absorbing glass of this invention, SiO2 is the main component forming the glass skeleton and plays a major role in the glass skeleton, while also improving chemical stability. The molar percentage of SiO2 is 68-78 mol.%, preferably 70-76 mol.%. When the SiO2 content is below 68.0 mol.%, it is difficult to obtain a coefficient of thermal expansion similar to that of the sheet glass, and it will also reduce the chemical stability of the glass; when the SiO2 content is above 78.0 mol.%, the high-temperature viscosity of the glass will increase, resulting in an excessively high glass melting temperature.

[0024] B₂O₃ is a glass-forming oxide and a component of the glass framework. It also acts as a flux to reduce the viscosity of molten glass. Boron trigonal [BO₃] and boron-oxygen tetrahedron [BO₄] are structural components. Under different conditions, boron may exist as trigonal [BO₃] or boron-oxygen tetrahedron [BO₄]. At high-temperature melting conditions, it is generally difficult to form boron-oxygen tetrahedra, and it can only exist as trihedrons. However, at low temperatures, under certain conditions, boron… 3+B₂O₃ tends to capture free oxygen to form tetrahedrons, resulting in a denser structure and increased low-temperature viscosity of the glass. However, due to its characteristic of decreasing glass viscosity at high temperatures and increasing it at low temperatures, its content range is relatively small. Nevertheless, an appropriate amount of B₂O₃ can effectively remove air bubbles from the molten glass during the glass melting process, greatly improving the optical uniformity of the glass molding. This characteristic is crucial for ensuring stable transmission of optical signals within the material, avoiding light scattering and signal distortion caused by internal defects, thus maintaining high image quality compatible with monochrome displays. The molar percentage of B₂O₃ is 2.0-10 mol.%, preferably 3.5-8.0 mol.%. A B₂O₃ content below 2.0 mol.% cannot act as a solubilizer and will reduce the chemical stability of the glass. A B₂O₃ content above 10.0 mol.% will increase the glass's tendency to separate phases.

[0025] Al₂O₃ is an intermediate oxide of glass. 3+ There are two coordination states: located in tetrahedra or octahedra. When there is sufficient oxygen in the glass, aluminum-oxygen tetrahedra [AlO4] are formed, forming a continuous network with silicon-oxygen tetrahedra. When there is insufficient oxygen in the glass, aluminum-oxygen octahedra [AlO6] are formed, which are the outer bodies of the network and are located in the vacancies of the silicon-oxygen network. Therefore, within a certain content range, it can be the main body for glass network formation along with SiO2. The molar percentage of Al2O3 is 1.0-9.0 mol.%, preferably 1.5-8.0 mol.%. An Al2O3 content below 1.0 mol.% will increase the coefficient of thermal expansion of the glass, while an Al2O3 content above 9.0 mol.% will significantly increase the high-temperature viscosity of the glass, raising the melting temperature of the glass, while decreasing the crystallization properties of the glass.

[0026] Na₂O is an oxide on the outer layer of the glass structure network. It also acts as a flux, significantly lowering the melting temperature of the glass, promoting uniform mixing of components during the glass melting process, and improving production efficiency. Simultaneously, Na₂O can fine-tune the optical properties of the glass, further optimizing the compatibility between the light-absorbing glass material and other glass materials in the fiber optic imaging element, ensuring performance matching of the entire fiber optic imaging element. The molar percentage of Na₂O is 1.0-10 mol.%, preferably 3.5-8 mol.%. When the Na₂O content exceeds 10 mol.%, it increases the coefficient of thermal expansion of the glass and increases its tendency to crystallize.

[0027] K2O is an external oxide of the glass structure network, and the molar percentage of K2O is 3.0-10 mol.%, preferably 4.5-9 mol.%. When the K2O content is greater than 10 mol.%, it will increase the coefficient of thermal expansion of the glass and increase the tendency of the glass to crystallize.

[0028] MgO is an oxide in the glass structure network and is used to regulate the glass crystallization temperature. The molar percentage of MgO is 0.1-1.5 mol.%, preferably 0.1-0.9 mol.%. When the MgO content is greater than 1.5 mol.%, it will increase the coefficient of thermal expansion and the tendency of the glass to crystallize.

[0029] CaO is an oxide in the glass structure network, with a molar percentage of 0.1-3.0 mol.%, preferably 0.5-2.5 mol.%. A CaO content greater than 3.0 mol.% will reduce the chemical stability of the glass.

[0030] SrO is an outer oxide of the glass structure network, used to regulate the glass crystallization temperature. The molar percentage of SrO is 0.1-0.5 mol.%, preferably 0.1-0.2 mol.%. An SrO content greater than 0.5 mol.% will reduce the chemical stability of the glass.

[0031] NiO is a light-absorbing colorant for light-absorbing glass, which can significantly enhance the glass material's ability to absorb light of specific wavelengths. Within a range that matches the display wavelength commonly used in monochrome displays (300-400nm), it can effectively improve light transmittance and reduce light reflection and scattering, thereby greatly improving image contrast and making the outlines of objects in the image clearer and more distinguishable. The molar percentage of NiO is 0.1-1.5 mol.%, preferably 0.2-0.8 mol.%. 2+ It has a good absorption effect in the visible light region. However, if the NiO content is greater than 1.5 mol.%, it will reduce the transmittance of the glass in the ultraviolet band and increase the tendency of the glass to crystallize.

[0032] Co2O3 is a light-absorbing colorant for light-absorbing glass, playing a crucial role in ultraviolet light transmittance and visible light absorption characteristics. As an important light-absorbing colorant, Co2O3 possesses the ability to precisely adjust the absorption degree of glass materials for different wavelengths of light. By precisely controlling its content, the absorption spectrum of the light-absorbing glass material can be made highly compatible with the optimal response spectrum of monochrome displays, achieving precise light absorption regulation. This regulation mechanism ensures that the color reproduction and grayscale performance of images on monochrome displays conform to human visual habits, greatly improving viewing comfort and reducing visual fatigue caused by prolonged observation. Co2O3 works synergistically with NiO to improve ultraviolet light transmittance and optimize the light absorption efficiency in the visible light range. This allows the images output from the fabricated fiber optic imaging element to present richer details when displayed on a monochrome display, improving image clarity and recognizability. The molar percentage of Co2O3 is 0.1-1.2 mol.%, preferably 0.3-0.9 mol.%. Co2O3 can combine with other coloring ions to form a stable morphology in the glass, thereby making the light absorption coloring performance more stable. When the Co2O3 content is greater than 1.2 mol.%, it will reduce the transmittance of the glass in the ultraviolet range and increase the tendency of the glass to crystallize.

[0033] MnO2 is a light-absorbing colorant for light-absorbing glass, and Mn 4+ It exhibits stable light absorption and filtering properties in the visible light wavelength range and can form stable coloring in glass. MnO2 can play a role in curing the coloring, thereby making the light absorption coloring and light transmittance properties more stable. The molar percentage of MnO2 is 0.1-0.8 mol.%, preferably 0.1-0.5 mol.%. When the MnO2 content is greater than 0.8 mol.%, it will reduce the transmittance of the glass in the ultraviolet band and increase the tendency of the glass to crystallize.

[0034] Nd₂O₃ is a light-absorbing colorant for light-absorbing glass, containing rare earth ions (Nd₂O₃). 3+ The spectral characteristics and light absorption capacity of Nd in glass are very stable, and Nd 3+ Strong absorption peaks are observed at 548 nm, 568 nm, and 588 nm, with a small amount of Nd. 3+ In glass, it can achieve a composite absorption effect, preventing the light absorption curve from showing a significant transmission peak in the visible light region. The molar percentage of Nd2O3 is 0.1-0.8 mol.%, preferably 0.2-0.8 mol.%. When the Nd2O3 content is greater than 0.8 mol.%, it will reduce the transmittance of the glass in the ultraviolet range and increase the tendency of the glass to crystallize.

[0035] Compared with the prior art, the light-absorbing glass for the optical fiber imaging element of the present invention has the following beneficial effects:

[0036] (1) The light-absorbing glass of the present invention has good light transmittance performance. With a thickness of 0.3±0.01mm, the spectral transmittance in the ultraviolet band of 300-400nm is >70%, which is highly matched with the best response spectrum of black and white display. It can accurately control the light signal and ensure that the image output by the fiber optic imaging element is perfectly compatible with the black and white display. It avoids problems such as image distortion, reflection, insufficient clarity, reduced contrast and halo, and provides users with a stable and clear observation experience.

[0037] (2) The light-absorbing glass of the present invention can efficiently absorb light in the wavelength range of 580-670nm. With a glass thickness of 0.3±0.01mm, the spectral transmittance of the visible light glass in the wavelength range of 580-670nm is less than 2.0%, which effectively reduces reflection, scattering and fluorescence interference, and greatly improves the contrast, clarity and color accuracy of the image.

[0038] (3) The light-absorbing glass of the present invention has a similar coefficient of thermal expansion and viscosity characteristics to the skin glass in optical fiber imaging elements. Its thermal properties meet the requirements of the optical fiber imaging element manufacturing process and it has good compatibility with the core-skin glass material. Its coefficient of thermal expansion at 30-300℃ is (77±2)×10. －7 / ℃.

[0039] (4) The optical fiber imaging element light-absorbing glass prepared by the present invention has the advantages of no stones or bubbles inside the glass after melting. It does not produce crystallization after being kept at 850℃ for 6 hours, and has good anti-crystallization performance.

[0040] (5) The light-absorbing glass of the present invention is applied to the optical fiber image transmission element. As a light-absorbing glass, it can effectively improve the imaging contrast and clarity of the optical fiber image transmission element. By precisely adjusting the absorption degree of light of different wavelengths by the light-absorbing glass material, the color reproduction and grayscale performance of the image in black and white display conform to the visual habits of the human eye, effectively reducing visual fatigue during viewing, improving the comfort of human eye viewing, and helping users maintain a good visual state during long-term observation.

[0041] (6) The light-absorbing glass of the present invention has good physicochemical stability and can maintain stable performance under different environmental conditions, and is not easily affected by factors such as temperature and humidity. This ensures that the compatibility and synergistic performance of the light-absorbing glass with P45 phosphor and other materials of fiber optic imaging elements will not decrease during long-term use, thus guaranteeing the long-term stable operation of the entire system and reducing maintenance costs.

[0042] (7) The method for preparing the light-absorbing glass provided by the present invention is simple. The preparation method uses common raw materials and mature glass preparation technology. The operation process is simple, the parameters of each step are clear and easy to control, the cost is low, and the total content of the light-absorbing colorant used does not exceed 2.0 mol.%. It is suitable for large-scale industrial production and can ensure the consistency and reliability of product quality. It provides solid technical support for the widespread application of the light-absorbing glass and is conducive to promoting the industrialization of related optical imaging products.

[0043] (8) The low-light image intensifier made with this light-absorbing glass presents rich image details, clear outlines and accurate color reproduction in related display systems, effectively improving the imaging quality of the low-light image intensifier system in conjunction with P45 phosphor, and meeting the needs of military, security, scientific research and other fields with stringent requirements for high-precision imaging.

[0044] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0045] Figure 1 A transmittance curve of a light-absorbing glass for an optical fiber imaging element in the 300-900 nm range, provided for an embodiment of the present invention;

[0046] Figure 2 A transmittance curve of a light-absorbing glass for an optical fiber imaging element at 300-400 nm is provided for an embodiment of the present invention.

[0047] Figure 3 The transmittance curve of a light-absorbing glass for an optical fiber imaging element provided in this embodiment of the invention is shown in the wavelength range of 580-670nm. Detailed Implementation

[0048] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with preferred embodiments, provides a detailed explanation of the specific implementation methods, structures, features, and effects of the present invention, but this is not intended to limit the scope of the invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0049] See Figure 1 , Figure 2 and Figure 3The figure shows the transmittance curve of the light-absorbing glass. As can be seen from the figure, at a thickness of 0.3±0.01mm, it has strong light absorption and filtering capabilities in the visible light wavelength range of 580-670nm, with a spectral transmittance of <2.0%, indicating a very obvious light absorption effect in the visible light band. At a thickness of 0.3±0.01mm, it has high transmittance in the ultraviolet wavelength range of 300-400nm, with a spectral transmittance of >70%, indicating a very obvious light transmittance effect in the ultraviolet band.

[0050] In this document, all “molar percentage mol.%” are based on the total molar amount of the final glass composition, and the glass chemical composition (mol.%) of the examples is detailed in Table 1.

[0051] The parameters, measurement methods, and instruments used to measure the light-absorbing glass of the present invention are as follows:

[0052] (1) The transmittance of the light-absorbing glass was determined using a transmittance tester;

[0053] (2) Average linear thermal expansion coefficient α at 30-300℃ 30 / 300 [×10 -7 [℃] was measured using a horizontal dilatometer, following the method specified in GB / T 16920-2015.

[0054] Table 1 Chemical composition (mol.%) and properties of light-absorbing glass examples

[0055]

[0056] Example 1

[0057] According to the glass composition in Example 1 of Table 1, the raw materials are selected to ensure that the formulation meets the glass chemical composition requirements of Table 1. Then, the light-absorbing glass is prepared according to the following steps:

[0058] (1) Raw material preparation: Weigh the raw materials quartz sand, boric acid, alumina, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide in the molar ratio, mix them evenly to obtain a raw material mixture;

[0059] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1500℃ for 8 hours. After the raw material mixture melts, it is stirred twice, each time at a speed of 150 rpm for 1 hour, to ensure that all components are fully and uniformly melted until a clear and homogeneous glass liquid is formed. Then, the material is discharged at 1420℃ and cast into a mold to form the required glass, forming a preliminary glassy structure. After the glass cools and solidifies, it is annealed at 600℃ for 24 hours. This yields a light-absorbing glass preform for optical fiber imaging elements.

[0060] (3) Blank processing: The light-absorbing glass blank after annealing and cooling is cut, ground and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements of the optical fiber imaging element and the optical matching requirements with P45 phosphor.

[0061] The glass sheet (thickness 0.30±0.01mm) made from the raw materials of Example 1 was tested and found to have a spectral transmittance of <2.0% in the visible light band of 580-670nm and a spectral transmittance of >70% in the ultraviolet band of 300-400nm. It did not crystallize after being kept at 850°C for 6 hours.

[0062] Example 2

[0063] According to the glass composition in Example 2 of Table 1, the raw materials are selected to ensure that the formulation meets the glass chemical composition requirements of Table 1. Then, the light-absorbing glass is prepared according to the following steps:

[0064] (1) Raw material preparation: Weigh the raw materials quartz sand, boric acid, alumina, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide in the molar ratio, mix them evenly to obtain a raw material mixture;

[0065] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1560℃ for 4 hours. After the raw material mixture melts, it is stirred three times at a speed of 180 rpm for 0.5 hours each time to ensure that all components are fully and uniformly melted until a clear and homogeneous glass liquid is formed. Then, the material is discharged at 1480℃ and cast into a mold to form the required glass, forming a preliminary glassy structure. After the glass cools and solidifies, it is annealed at 560℃ for 36 hours. This yields a light-absorbing glass preform for optical fiber imaging elements.

[0066] (3) Blank processing: The light-absorbing glass blank after annealing and cooling is cut, ground and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements of the optical fiber imaging element and the optical matching requirements with P45 phosphor.

[0067] The glass sheet (thickness 0.30±0.01mm) made from the raw materials of Example 2 was tested and found to have a spectral transmittance of <2.0% in the visible light wavelength range of 580-670nm and a spectral transmittance of >70% in the ultraviolet wavelength range of 300-400nm. It did not crystallize after being kept at 850°C for 6 hours.

[0068] Example 3

[0069] According to the glass composition in Example 3 of Table 1, the raw materials are selected to ensure that the formulation meets the glass chemical composition requirements of Table 1. Then, the light-absorbing glass is prepared according to the following steps:

[0070] (1) Raw material preparation: Weigh the raw materials quartz sand, boric acid, alumina, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide in the molar ratio, mix them evenly to obtain a raw material mixture;

[0071] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1550℃ for 6 hours. After the raw material mixture melts, it is stirred twice, each time at a speed of 160 rpm for 0.5 hours, to ensure that all components are fully and uniformly melted until a clear and homogeneous glass liquid is formed. Then, the material is discharged at 1430℃ and cast into a mold to form the required glass, forming a preliminary glassy structure. After the glass cools and solidifies, it is annealed at 580℃ for 28 hours. This yields a light-absorbing glass preform for optical fiber imaging elements.

[0072] (3) Blank processing: The light-absorbing glass blank after annealing and cooling is cut, ground and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements of the optical fiber imaging element and the optical matching requirements with P45 phosphor.

[0073] The glass sheet (thickness 0.30±0.01mm) made from the raw materials of Example 3 was tested and found to have a spectral transmittance of <2.0% in the visible light band of 580-670nm and a spectral transmittance of >70% in the ultraviolet band of 300-400nm. It did not crystallize after being kept at 850°C for 6 hours.

[0074] Example 4

[0075] According to the glass composition in Example 4 of Table 1, the raw materials are selected to ensure that the formulation meets the glass chemical composition requirements of Table 1. Then, the light-absorbing glass is prepared according to the following steps:

[0076] (1) Raw material preparation: Weigh the raw materials quartz sand, boric acid, alumina, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide in the molar ratio, mix them evenly to obtain a raw material mixture;

[0077] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1540℃ for 7 hours. After the raw material mixture melts, it is stirred three times at a speed of 150 rpm for 1 hour each time to ensure that all components are fully and uniformly melted until a clear and homogeneous glass liquid is formed. Then, the material is discharged at 1450℃ and cast into a mold to form the required glass, forming a preliminary glassy structure. After the glass cools and solidifies, it is annealed at 570℃ for 26 hours. This yields a light-absorbing glass preform for optical fiber imaging elements.

[0078] (3) Blank processing: The light-absorbing glass blank after annealing and cooling is cut, ground and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements of the optical fiber imaging element and the optical matching requirements with P45 phosphor.

[0079] The glass sheet (thickness 0.30±0.01mm) made from the raw materials of Example 4 was tested and found to have a spectral transmittance of <2.0% in the visible light band of 580-670nm and a spectral transmittance of >70% in the ultraviolet band of 300-400nm. It did not crystallize after being kept at 850°C for 6 hours.

[0080] Example 5

[0081] According to the glass composition in Example 5 of Table 1, the raw materials are selected to ensure that the formulation meets the glass chemical composition requirements of Table 1. Then, the light-absorbing glass is prepared according to the following steps:

[0082] (1) Raw material preparation: Weigh the raw materials quartz sand, boric acid, alumina, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide in the molar ratio, mix them evenly to obtain a raw material mixture;

[0083] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1530℃ for 8 hours. After the raw material mixture melts, it is stirred twice, each time at a speed of 170 rpm for 0.5 hours, to ensure that all components are fully and uniformly melted until a clear and homogeneous glass liquid is formed. Then, the material is discharged at 1460℃ and cast into a mold to form the required glass, forming a preliminary glassy structure. After the glass cools and solidifies, it is annealed at 590℃ for 27 hours. This yields a light-absorbing glass preform for optical fiber imaging elements.

[0084] (3) Blank processing: The light-absorbing glass blank after annealing and cooling is cut, ground and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements of the optical fiber imaging element and the optical matching requirements with P45 phosphor.

[0085] The glass sheet (thickness 0.30±0.01mm) made from the raw materials of Example 5 was tested and found to have a spectral transmittance of <2.0% in the visible light band of 580-670nm and a spectral transmittance of >70% in the ultraviolet band of 300-400nm. It did not crystallize after being kept at 850°C for 6 hours.

[0086] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A composition of light-absorbing glass for fiber optic imaging elements, characterized in that, It consists of the following components in molar percentage: The total content of colorant in the light-absorbing glass is not greater than 2.0 mol.%. The colorant in the light-absorbing glass is composed of NiO, Co2O3, MnO2 and Nd2O3.

2. The composition according to claim 1, characterized in that, It consists of the following components in molar percentage:

3. The composition according to claim 2, characterized in that, It consists of the following components in molar percentage:

4. A method for preparing a light-absorbing glass for an optical fiber imaging element using the composition according to any one of claims 1-3, characterized in that, Includes the following steps: (1) Raw material preparation: Mix the raw materials evenly according to the proportion to obtain a raw material mixture; (2) Glass melting: The raw material mixture is added to the crucible and melted at the first preset temperature. After the raw material mixture melts, it is stirred to make the components fully and uniformly melted until a clear and homogeneous glass liquid is formed. Then, it is discharged at the second preset temperature and cast into the mold to form the required glass, forming a preliminary glass structure. After the glass cools and solidifies, it is annealed to obtain a light-absorbing glass blank for optical fiber imaging elements. (3) Blank processing: The light-absorbing glass blank after annealing and cooling is cut, ground and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements of the optical fiber imaging element and the optical matching requirements with P45 phosphor.

5. The preparation method according to claim 4, characterized in that, The first preset temperature is 1500-1560℃, and the melting time is 4-8 hours.

6. The preparation method according to claim 5, characterized in that, The stirring is performed 2-3 times, with a stirring speed of 150-180 rpm each time, and the stirring time is 0.5-1 hour.

7. The preparation method according to claim 6, characterized in that, The second preset temperature is 1420-1480℃; the annealing temperature is 560-600℃, and the annealing time is 24-36 hours.

8. A light-absorbing glass for fiber optic imaging elements, characterized in that, The light-absorbing glass is prepared according to the preparation method described in any one of claims 4-7; the light-absorbing glass, with a thickness of 0.30±0.01 mm, has a spectral transmittance >70% in the ultraviolet wavelength range of 300-400 nm, and a spectral transmittance <2.0% in the visible light wavelength range of 580-670 nm; the coefficient of thermal expansion at 30-300℃ is (77±2)×10⁻⁶. －7 / ℃; no crystallization occurs when held at 850℃ for 6 hours.

9. The application of the light-absorbing glass for fiber optic imaging elements as described in claim 8 in a low-light image intensifier.

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