A fiber optic inverter compatible with black-and-white display and a preparation method and application thereof

Abstract

The application relates to a black-and-white display compatible optical fiber inverter and a preparation method and application thereof, and the preparation method comprises the following steps: drawing of light absorption filaments and monofilaments: drawing of light absorption material glass for a black-and-white display compatible optical fiber inverter into light absorption filaments; drawing of secondary multifilaments; hot melt compression molding; torsion molding; and preparation of the black-and-white display compatible optical fiber inverter. The black-and-white display compatible optical fiber inverter has the advantages of high resolution, high contrast, clear imaging, uniform transmittance, excellent internal quality and the like, and the application of the black-and-white display compatible optical fiber inverter in a low-light image intensifier can effectively improve the observation clarity and resolution of the low-light image tube, the product can meet the matching demand of the low-light night vision industry, can replace traditional optical fiber inverter products, and improve the comprehensive use performance.

Description

Technical Field

[0001] This invention relates to the field of fiber optic image reversal manufacturing, and particularly to a fiber optic image reversal compatible with black and white displays, its manufacturing method, and its applications. Background Technology

[0002] "Low light" generally refers to faint light or light with energy too low to be visible at night or in low light conditions. Low-light night vision technology converts low-light images into enhanced optical images using a device called an image intensifier, enabling direct observation at night or in low light conditions. Low-light night vision devices utilize the low-brightness natural light reflected from targets at night, such as sky light, starlight, moonlight, and atmospheric glow. The low-light image intensifier amplifies this light tens of thousands of times, achieving an effect suitable for naked-eye observation at night. This allows them to operate using sky light, thus providing better concealment and enabling them to strike the enemy. Like telescopes and microscopes, low-light night vision devices are visual aids for the human eye. They enhance images that are unclear or invisible in night or dark conditions into images visible to the human eye, allowing humans to see as clearly as in daylight. Low-light image intensifiers expand the temporal and spatial scope of human activities and the ability to acquire information and images, extending human activity from daytime to nighttime and from bright environments to dark situations, even in the absence of artificial lighting.

[0003] Image intensifiers, as the core component of low-light night vision devices, have wide applications in numerous fields such as military, criminal investigation, aerospace, and medicine. Their working principle involves converting weak optical images through photoelectric conversion using a photocathode, electrical signal amplification using an electron multiplier, and electro-optic conversion using a fluorescent screen. This process transforms targets in extremely low or no light, invisible to the human eye, into easily identifiable visible light images, increasing brightness by 10%. 4More than twice as much. As the image output terminal of a low-light image intensifier, the performance of the phosphor screen directly affects image brightness, image detail reproduction, and the quality of image coupling transmission. It is one of the main components of the image intensifier, and its main function is to convert electrical images into optical images. Therefore, the luminous performance of the phosphor screen is closely related to the performance of the low-light image intensifier. The luminous performance of the phosphor screen mainly depends on the performance of the phosphor substrate, the phosphor, and the manufacturing process of the phosphor screen. Different phosphor types directly affect the image output effects such as image brightness, image detail, and field of view intensity. Commonly used phosphor types in low-light image intensifiers include yellow-green (green) phosphors such as P20 ((Zn,Cd)S∶Ag), P22 (ZnS∶Cu,Al), P31 (ZnS∶Cu), and P43 (Gd2O2S∶Tb), and white phosphors such as P45 (Y2O2S∶Tb). Since low-light image intensifiers are used in direct-view optical systems, the emission spectrum of the phosphor screen used as the image output end should have good human eye adaptability. Commonly used phosphors such as P20, P22, P31, and P43 have peak wavelengths around 540nm, emitting yellow-green light. While this yellow-green wavelength is the most sensitive for the human eye, prolonged viewing can cause eye strain. The most comfortable viewing experience is with P45 phosphor for monochrome displays. The spectral response wavelength of this monochrome display falls largely within the comfortable viewing range for the human eye, making it both sensitive and comfortable. This is because, under low-light conditions, the human eye is more sensitive to black-and-white contrast than to color discrimination. Monochrome displays can convert weak light signals into clear black-and-white images, making it easier for the human eye to identify and distinguish image details. For example, in military night reconnaissance missions, when soldiers observe targets through a low-light image intensifier, the monochrome image clearly presents the target's outline, location, and other key information without the difficulty of information recognition caused by color interference. Secondly, monochrome displays have a fast response speed. In low-light environments, where light changes rapidly, a fast response time ensures that the screen captures and displays these changes in real time, preventing image blurring. In nighttime investigations at criminal scenes, a fast-response monochrome display can clearly record fleeting suspicious clues, providing crucial visual evidence for case solving. Furthermore, monochrome displays have relatively low manufacturing costs and high stability. Their cost advantage is significant when applied on a large scale to various low-light imaging devices, while their high stability ensures reliable operation over extended periods in complex environments. For low-light detection equipment in the aerospace field, where extremely high stability is required, the stable performance of monochrome displays makes them an ideal choice.

[0004] Fiber optic image reversers are core optical components in low-light night vision devices. In the imaging system of low-light image intensifiers, the fiber optic image reverser plays a crucial role, serving as the optical output window. It can reverse the image 180° for transmission and boasts advantages such as large numerical aperture, high light transmission efficiency, high resolution, clear transmission, zero optical thickness, simple structure, small size, and light weight. It can effectively replace the relay lens system in low-light night vision devices, playing a vital role in improving the quality of imaging devices and representing a cutting-edge high-tech product in the global optoelectronics industry. Black and white display low-light night vision technology places high demands on the matching fiber optic image reversers, requiring not only high sharpness (including resolution and contrast) but also perfect compatibility with the phosphor used in black and white displays. However, existing fiber optic image reversers present some problems that urgently need to be solved when used with black and white phosphor screens. On the one hand, traditional 6μm or 4μm fiber optic image inverter materials have poor compatibility with monochrome fluorescent screens, making it difficult to meet the imaging requirements of monochrome displays. This leads to information loss and reduced contrast during image transmission, resulting in a less clear final image and affecting the human eye's viewing experience. On the other hand, in low-light environments, sufficient image clarity and a suitable brightness range are required to ensure comfortable viewing for the human eye. However, existing fiber optic image inverters, especially when working in conjunction with monochrome fluorescent screens, fail to fully meet these requirements in terms of image quality, limiting the performance of low-light image intensifiers in practical applications.

[0005] The image transmission mechanism of a fiber optic image reversal device utilizes the principle of total internal reflection of optical fibers. The optical fibers constituting the fiber optic image reversal device 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 hot-melt pressing process with vacuum drawing. 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 field or uneven drawing force during the manufacturing process may cause uneven wall thickness of the cladding glass tube, resulting in light penetration during total internal reflection and causing 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 the fiber optic image reversal device.

[0006] To address the issues of light crosstalk and leakage between optical fibers in fiber optic image inverters, a common method 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 absorbent filaments and inserting them into the gaps between the arranged optical fibers. However, it cannot completely achieve optical insulation; 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 optical fiber sheath to achieve optical insulation, thereby improving 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 optical components. However, with the expansion of application fields, higher requirements have been put forward in recent years for ultra-thin, lightweight, high-definition, high-contrast fiber optic image converters that are compatible with black and white displays. Therefore, the light absorption effect of the light-absorbing glass is required to meet the compatibility and adaptability of black and white displays. It is necessary not only to absorb stray light more thoroughly, but also to cover the ultraviolet, visible and near-infrared bands, so as to achieve the requirements of low transmittance in the bands that need to be cut off and high transmittance in the bands that need to be adapted.

[0007] Due to the inherent concentration difference in composition between the light-absorbing glass and the low-refractive-index skin glass in the fiber optic image transmission element, ion diffusion and interpenetration of varying degrees are inevitable during the thermal processing. Furthermore, since the fiber optic image inverter in the fiber optic image transmission element also undergoes an additional thermal torsion process, the degree of ion diffusion and interpenetration between the two components at the interface between the glass material and the skin material is more severe than that of the fiber optic panel, resulting in a certain degree of decrease in the transmission characteristics of the fiber optic image inverter, such as transmittance and contrast.

[0008] Ordinary light-absorbing glass still has high transmittance in the visible light range at a thickness of 0.5mm. As the thickness decreases, the transmittance gradually increases. However, traditional light-absorbing materials in fiber optic image converters generally suffer from problems such as low stray light absorption efficiency, poor imaging contrast, and incompatibility with black and white displays. In particular, the light-absorbing glass used in fiber optic image converters compatible with black and white displays cannot meet the application requirements of high definition, high contrast, and black and white display compatibility. Summary of the Invention

[0009] To address the aforementioned problems in the prior art, this invention provides a fiber optic image inverter compatible with monochrome displays and its fabrication method. This fiber optic image inverter is compatible with low-light night vision technology for monochrome displays and has perfect compatibility with the phosphors used in monochrome displays, thus meeting the requirements for high-definition imaging in monochrome displays.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for fabricating a fiber optic image reverser compatible with monochrome displays includes the following steps:

[0012] (1) Drawing of light-absorbing filaments and monofilaments: A light-absorbing glass material used in fiber optic image converters compatible with black and white displays is drawn into light-absorbing filaments; a low-refractive-index sheath glass tube is matched with a high-refractive-index core glass rod and then drawn into monofilaments;

[0013] (2) Drawing of primary multifilament: The drawn monofilaments are arranged into a primary composite rod with a cross-section of a regular hexagon, and the light-absorbing filaments are evenly filled into the triangular holes of the primary composite rod; the primary composite rod assembled above is drawn into a primary multifilament.

[0014] (3) Drawing of secondary multifilaments: The drawn primary multifilaments are arranged into secondary composite rods with a cross-section of a regular hexagon. The secondary composite rods are then drawn into secondary multifilaments. The secondary multifilaments are cut to a fixed length and arranged into screen panel segments.

[0015] (4) Hot melt pressing: The screen panel segment is placed in the hot melt pressing furnace and hot melt pressing is carried out according to the designed compression ratio of the panel segment before and after hot melt pressing. After hot melt pressing under high temperature and pressure, the fiber optic image converter blank panel segment is obtained.

[0016] (5) Twist forming: After the hot melt pressing formed fiber optic image converter blank is rolled, cut, ground and hexagonally processed to prepare fiber optic image converter blank, the fiber optic image converter blank is twisted at a 180° angle in a twist forming furnace to prepare a fiber optic image converter compatible with black and white display.

[0017] The composition of the light-absorbing glass for a fiber optic image converter compatible with monochrome displays comprises the following components in molar percentage: SiO2 68-78%, B2O3 2-10%, Al2O3 1-9%, Na2O 1-10%, K2O 3-10%, MgO 0.1-1.5%, CaO 0.1-3.0%, SrO 0.1-0.5%, NiO 0.1-1.5%, Co2O3 0.1-1.2%, MnO2 0.1-0.8%, and Nd2O3 0.1-0.8%.

[0018] The diameter of the light-absorbing filament is Φ0.58-0.74mm; the number of inserted light-absorbing filaments is 6N, where 2≤N≤5.

[0019] In the primary composite rod, the diameter of the monofilament is Φ3.8mm~4.8mm, and the number of monofilaments on each side is 6; the number of primary multifilaments on each side of the secondary composite rod is 10~15, the hexagonal side dimension of the primary multifilament is 1.51mm~1.80mm, and the hexagonal side dimension of the secondary multifilament is 0.60~0.89mm.

[0020] The fiber filament diameter of the fiber reversor prepared is ≤3.0μm, which is compatible with black and white displays.

[0021] The composition of the light-absorbing glass for the fiber optic image inverter compatible with monochrome displays preferably comprises the following components in molar percentage: SiO2 70-76%, B2O3 3.5-8%, Al2O3 1.5-8%, Na2O 3.5-8%, K2O 4.5-9%, MgO 0.1-0.9%, CaO 0.5-2.5%, SrO 0.1-0.2%, NiO 0.2-0.8%, Co2O3 0.3-0.9%, MnO2 0.1-0.5%, and Nd2O3 0.2-0.8%.

[0022] The composition of the light-absorbing glass for a fiber optic image converter compatible with monochrome displays more preferably comprises the following components in molar percentage: SiO2 73.1%, B2O3 5.6%, Al2O3 4.8%, Na2O 5.8%, K2O 6.6%, MgO 0.5%, CaO 1.6%, SrO 0.1%, NiO 0.2%, Co2O3 0.6%, MnO2 0.3%, and Nd2O3 0.8%.

[0023] The method for preparing the light-absorbing glass for a fiber optic image inverter compatible with monochrome displays includes the following steps:

[0024] (1) Raw material preparation: Mix the raw materials evenly according to the proportion of the composition to obtain the raw material mixture;

[0025] (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.

[0026] (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.

[0027] The first preset temperature is 1500-1560℃, and the melting time is 4-8 hours.

[0028] 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.

[0029] The second preset temperature is 1420-1480℃; the annealing temperature is 560-600℃, and the annealing time is 24-36 hours.

[0030] This invention improves the light absorption and transmittance of existing light-absorbing glass by modifying the colorant composition ratio, reducing ion diffusion and interpenetration between the light-absorbing glass and the skin glass, and optimizing the preparation technology. When the light-absorbing glass of this invention is used in fiber optic image inverters, it can effectively improve the imaging contrast and clarity of the fiber optic image inverter. The prepared fiber optic image inverter has the advantages of high resolution, high contrast, high transmittance, and high uniformity, and is especially suitable for fiber optic image inverter products compatible with black and white displays.

[0031] The total content of colorants NiO, Co2O3, MnO2, and Nd2O3 in the light-absorbing glass is no more than 2.0 mol.%; the light-absorbing glass for fiber optic image converters compatible with monochrome displays, 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; and a coefficient of thermal expansion of (77±2)×10 at 30-300℃. －7 / ℃; no crystallization occurs when held at 850℃ for 6 hours.

[0032] The present invention also provides a fiber optic image inverter compatible with black and white displays, which is prepared according to the preparation method described above.

[0033] The fiber optic image reversor compatible with monochrome displays has a unit fiber diameter ≤3.0μm and a center resolution >190lp / mm; crosstalk at 0.1mm from the blade edge is less than <1.0%, exhibiting excellent fixed pattern noise performance; no obvious multifilament boundary is observed under a 10x microscope; collimated light transmittance is >70% in the 380-780nm wavelength range, and transmittance uniformity is <0.5%.

[0034] The present invention further provides an application of the aforementioned fiber optic image inverter compatible with black and white displays in a low-light image intensifier. This fiber optic image inverter can achieve perfect compatibility with P45 phosphor black and white displays and can effectively improve the display clarity of low-light night vision devices.

[0035] Compared with the prior art, the fiber optic image inverter compatible with monochrome displays of the present invention has the following advantages:

[0036] (1) The fiber optic image converter of the present invention achieves high transmittance in the ultraviolet band through special optical structure design and material control, thereby enabling the fiber optic image converter and black and white fluorescent display to work together better, the transmission of light signals between the two is more efficient, the uniformity of light emission of the fluorescent screen is improved, thereby improving the overall imaging quality and making the image observed by the human eye clearer and more natural.

[0037] (2) The fiber optic image converter compatible with black and white display of this invention can effectively reduce the transmittance of visible light band by optimizing the composition of the core light-absorbing glass material, thereby effectively reducing the cross-light phenomenon between optical fibers, improving the contrast and clarity of the image, and using fewer light-absorbing wires to achieve the effect of less than 1.0% cross-light at 0.1mm from the blade edge.

[0038] (3) The fiber optic image converter compatible with black and white display of the present invention has high resolution, with a unit fiber diameter ≤3.0μm and a center resolution greater than 190lp / mm, which is a significant improvement over the prior art;

[0039] (4) The fiber optic image converter compatible with black and white displays of this invention has high transmittance and transmittance uniformity. In the wavelength range of 380-780nm, the collimated light transmittance is >70% and the transmittance uniformity is <0.5%.

[0040] (5) The fiber optic image inverter compatible with black and white displays of this invention has excellent fixed pattern noise performance and no obvious multifilament boundary is observed under a 10x microscope.

[0041] (6) Due to the improved imaging clarity and compatibility with black and white fluorescent displays, the fiber optic image inverter of the present invention makes the image output by the low-light image intensifier more suitable for human eye observation in terms of brightness, contrast and color reproduction. In low-light environments, the human eye can more easily and comfortably identify image details, reduce visual fatigue, and improve the practicality of the low-light image intensifier in practical applications.

[0042] The fiber optic image inverter compatible with monochrome displays of this invention has advantages such as high resolution, high contrast, clear imaging, uniform transmittance, and excellent internal quality. When applied to low-light image intensifiers, the fiber optic image inverter of this invention can effectively improve the observation clarity and resolution of low-light image tubes. Its products can meet the supporting needs of the low-light night vision industry and can also replace traditional fiber optic image inverter products, improve overall performance, and promote the development of optoelectronic devices in related fields such as space vision measurement and detection imaging towards high performance and wide field of view. It has a very good application and promotion prospect.

[0043] 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

[0044] Figure 1 A contrast test diagram of an optical fiber image reversor provided in an embodiment of the present invention;

[0045] Figure 2 The transmittance curve of the light-absorbing glass provided in the embodiment of the present invention. Detailed Implementation

[0046] 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.

[0047] Table 1 Chemical composition (mol.%) and properties of light-absorbing glass examples

[0048]

[0049] See Figure 1 The image shown is a contrast test diagram of a fiber optic image inverter compatible with black and white displays provided in an embodiment of the present invention. It can be seen that the crosstalk at a distance of 0.1 mm from the blade edge has an effect of less than 1.0%.

[0050] See Figure 2 Figure 1 shows the transmittance curve of the light-absorbing glass. It can be seen that when the total content of colorants NiO, Co2O3, MnO2, and Nd2O3 in the light-absorbing glass used in this invention is no greater than 2.0 mol.%, it exhibits strong light absorption and filtering capabilities in the visible light band of 580-670 nm at a thickness of 0.3 ± 0.01 mm, with a spectral transmittance < 2.0%, demonstrating a very significant absorption effect on visible light. Furthermore, at a thickness of 0.3 ± 0.01 mm, it exhibits high transmittance in the ultraviolet band of 300-400 nm, with a spectral transmittance > 70%, showing a very significant effect on ultraviolet light transmittance.

[0051] 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.

[0052] The parameters, measurement methods, and instruments used to measure the light-absorbing glass of the present invention are as follows:

[0053] (1) The transmittance of the light-absorbing glass was determined using a transmittance tester;

[0054] (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.

[0055] Example 1

[0056] A method for fabricating a fiber optic image reverser compatible with monochrome displays includes the following steps:

[0057] (1) Drawing of light-absorbing filaments and monofilaments:

[0058] a. Preparation of light-absorbing glass;

[0059] 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:

[0060] (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;

[0061] (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.

[0062] (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.

[0063] b. Draw light-absorbing glass with good surface finish into light-absorbing filaments with a diameter of 0.74 mm;

[0064] c. After matching the low-refractive-index glass tube with the high-refractive-index core glass rod, draw it into a monofilament with a diameter of Φ4.8mm;

[0065] (2) Drawing of primary composite wire: The drawn monofilaments are arranged into a primary composite rod with a cross-section of a regular hexagon, with 6 monofilaments on each side, and the light-absorbing wires are evenly filled into the triangular gaps of the primary composite rod. The number of light-absorbing wires inserted is 24. The primary composite rod assembled above is drawn into a primary composite wire. The hexagonal side dimension of the primary composite wire is 1.8mm.

[0066] (3) Drawing of secondary multifilaments: The drawn primary multifilaments are arranged into a secondary composite rod with a cross-section of a regular hexagon. The number of primary multifilaments on each side of the secondary composite rod is 10. The secondary composite rod is then drawn into secondary multifilaments. The hexagonal side dimension of the secondary multifilaments is 0.60mm. The secondary multifilaments are cut to a fixed length and arranged into screen panel segments.

[0067] (4) Hot melt pressing: The screen panel segment is placed in the hot melt pressing furnace and hot melt pressing is carried out according to the designed compression ratio of the panel segment before and after hot melt pressing. After hot melt pressing under high temperature and pressure, the fiber optic image converter blank panel segment is obtained.

[0068] (5) Twist forming: After the hot-melt press forming of the fiber optic image converter blank, the blank is rolled, cut, ground and hexagonal processed to prepare the fiber optic image converter blank. The fiber optic image converter blank is then twisted at a 180° angle in a twist forming furnace to obtain a fiber optic image converter compatible with black and white display.

[0069] The fabricated fiber reciprocator, compatible with monochrome displays, has a unit fiber diameter of 2.97 μm and a center resolution of 203 lp / mm. It exhibits excellent fixed pattern noise performance at a distance of 0.1 mm from the blade edge, with no obvious multifilament boundary observed under a 10x microscope. The collimated light transmittance is >70% in the 380-780 nm wavelength range, and the transmittance uniformity is <0.5%.

[0070] Example 2

[0071] A method for fabricating a fiber optic image reverser compatible with monochrome displays includes the following steps:

[0072] (1) Drawing of light-absorbing filaments and monofilaments:

[0073] a. Preparation of light-absorbing glass;

[0074] 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:

[0075] (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;

[0076] (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.

[0077] (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.

[0078] b. Draw light-absorbing glass with good surface finish into light-absorbing filaments with a diameter of 0.62 mm;

[0079] c. After matching the low-refractive-index glass tube with the high-refractive-index core glass rod, draw it into a monofilament with a diameter of Φ4.1mm;

[0080] (2) Drawing of primary composite wire: The drawn monofilaments are arranged into a primary composite rod with a cross-section of a regular hexagon, with 6 monofilaments on each side, and the light-absorbing wires are evenly filled into the triangular gaps of the primary composite rod. The number of light-absorbing wires inserted is 24. The primary composite rod assembled above is drawn into a primary composite wire. The hexagonal side dimension of the primary composite wire is 1.6mm.

[0081] (3) Drawing of secondary multifilaments: The drawn primary multifilaments are arranged into a secondary composite rod with a cross-section of a regular hexagon. The number of primary multifilaments on each side of the secondary composite rod is 12. The secondary composite rod is then drawn into secondary multifilaments. The hexagonal side dimension of the secondary multifilaments is 0.71mm. The secondary multifilaments are cut to a fixed length and arranged into screen panel segments.

[0082] (4) Hot melt pressing: The screen panel segment is placed in the hot melt pressing furnace and hot melt pressing is carried out according to the designed compression ratio of the panel segment before and after hot melt pressing. After hot melt pressing under high temperature and pressure, the fiber optic image converter blank panel segment is obtained.

[0083] (5) Twist forming: After the hot-melt press forming of the fiber optic image converter blank, the blank is rolled, cut, ground and hexagonal processed to prepare the fiber optic image converter blank. The fiber optic image converter blank is then twisted at a 180° angle in a twist forming furnace to obtain a fiber optic image converter compatible with black and white display.

[0084] The fabricated fiber optic image reciprocator, compatible with monochrome displays, has a unit fiber diameter of 2.98 μm and a center resolution of 203 lp / mm. It exhibits excellent fixed pattern noise performance at a distance of 0.1 mm from the blade edge, with no obvious multifilament boundary observed under a 10x microscope. The collimated light transmittance is >70% in the 380-780 nm wavelength range, and the transmittance uniformity is <0.5%.

[0085] Example 3

[0086] A method for fabricating a fiber optic image reverser compatible with monochrome displays includes the following steps:

[0087] (1) Drawing of light-absorbing filaments and monofilaments:

[0088] a. Preparation of light-absorbing glass;

[0089] 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:

[0090] (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;

[0091] (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.

[0092] (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.

[0093] b. Draw light-absorbing glass with good surface finish into light-absorbing filaments with a diameter of 0.58 mm;

[0094] c. After matching the low-refractive-index glass tube with the high-refractive-index core glass rod, draw it into a monofilament with a diameter of Φ3.8mm;

[0095] (2) Drawing of primary composite wire: The drawn monofilaments are arranged into a primary composite rod with a cross-section of a regular hexagon, with 6 monofilaments on each side, and the light-absorbing wires are evenly inserted into the triangular gaps of the primary composite rod, with 30 light-absorbing wires inserted. The primary composite rod assembled above is drawn into a primary composite wire, and the hexagonal side dimension of the primary composite wire is 1.51mm.

[0096] (3) Drawing of secondary multifilaments: The drawn primary multifilaments are arranged into secondary composite rods with a cross-section of a regular hexagon. Each side of the secondary composite rod has 15 primary multifilaments. The secondary composite rod is then drawn into secondary multifilaments. The hexagonal side dimension of the secondary multifilaments is 0.89mm. The secondary multifilaments are cut to a fixed length and arranged into screen panel segments.

[0097] (4) Hot melt pressing: The screen panel segment is placed in the hot melt pressing furnace and hot melt pressing is carried out according to the designed compression ratio of the panel segment before and after hot melt pressing. After hot melt pressing under high temperature and pressure, the fiber optic image converter blank panel segment is obtained.

[0098] (5) Twist forming: After the hot-melt press forming of the fiber optic image converter blank, the blank is rolled, cut, ground and hexagonal processed to prepare the fiber optic image converter blank. The fiber optic image converter blank is then twisted at a 180° angle in a twist forming furnace to obtain a fiber optic image converter compatible with black and white display.

[0099] The fiber optic image reciprocator, which is compatible with monochrome displays, has a unit fiber diameter of 2.94 μm and a center resolution of 203 lp / mm. It exhibits excellent fixed pattern noise performance at a distance of 0.1 mm from the blade edge and no obvious multifilament boundary is observed under a 10x microscope. The collimated light transmittance is >70% in the wavelength range of 380-780 nm, and the transmittance uniformity is <0.5%.

[0100] Example 4

[0101] A method for fabricating a fiber optic image reverser compatible with monochrome displays includes the following steps:

[0102] (1) Drawing of light-absorbing filaments and monofilaments:

[0103] a. Preparation of light-absorbing glass;

[0104] 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:

[0105] (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;

[0106] (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.

[0107] (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.

[0108] b. Draw light-absorbing glass with good surface finish into light-absorbing filaments with a diameter of 0.70 mm;

[0109] c. After matching the low-refractive-index glass tube with the high-refractive-index core glass rod, draw it into a monofilament with a diameter of Φ4.6mm;

[0110] (2) Drawing of primary multifilament: The drawn monofilaments are arranged into a primary composite rod with a cross-section of a regular hexagon, with 6 monofilaments on each side, and the light-absorbing wires are evenly filled into the triangular gaps of the primary composite rod. The number of light-absorbing wires inserted is 18. The primary composite rod assembled above is drawn into a primary multifilament, and the hexagonal side dimension of the primary multifilament is 1.7mm.

[0111] (3) Drawing of secondary multifilaments: The drawn primary multifilaments are arranged into a secondary composite rod with a cross-section of a regular hexagon. The number of primary multifilaments on each side of the secondary composite rod is 13. The secondary composite rod is then drawn into secondary multifilaments. The hexagonal side dimension of the secondary multifilaments is 0.77mm. The secondary multifilaments are cut to a fixed length and arranged into screen panel segments.

[0112] (4) Hot melt pressing: The screen panel segment is placed in the hot melt pressing furnace and hot melt pressing is carried out according to the designed compression ratio of the panel segment before and after hot melt pressing. After hot melt pressing under high temperature and pressure, the fiber optic image converter blank panel segment is obtained.

[0113] (5) Twist forming: After the hot-melt press forming of the fiber optic image converter blank, the blank is rolled, cut, ground and hexagonal processed to prepare the fiber optic image converter blank. The fiber optic image converter blank is then twisted at a 180° angle in a twist forming furnace to obtain a fiber optic image converter compatible with black and white display.

[0114] The fabricated fiber optic image reversor compatible with monochrome displays has a unit fiber diameter of 2.94 μm and a center resolution of 203 lp / mm. It exhibits a crosstalk of 0.95% at a distance of 0.1 mm from the blade edge, excellent fixed pattern noise performance, and no obvious multifilament boundary observed under a 10x microscope. The collimated light transmittance is >70% in the wavelength range of 380-780 nm, and the transmittance uniformity is <0.5%.

[0115] Example 5

[0116] A method for fabricating a fiber optic image reverser compatible with monochrome displays includes the following steps:

[0117] (1) Drawing of light-absorbing filaments and monofilaments:

[0118] a. Preparation of light-absorbing glass;

[0119] 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:

[0120] (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;

[0121] (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.

[0122] (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.

[0123] b. Draw light-absorbing glass with good surface finish into light-absorbing filaments with a diameter of 0.64 mm;

[0124] c. After matching the low-refractive-index glass tube with the high-refractive-index core glass rod, draw it into a monofilament with a diameter of Φ4.2mm;

[0125] (2) Drawing of primary composite wire: The drawn monofilaments are arranged into a primary composite rod with a cross-section of a regular hexagon, with 6 monofilaments on each side, and the light-absorbing wires are evenly filled into the triangular gaps of the primary composite rod. The number of light-absorbing wires inserted is 30. The primary composite rod assembled above is drawn into a primary composite wire. The hexagonal side dimension of the primary composite wire is 1.8mm.

[0126] (3) Drawing of secondary multifilaments: The drawn primary multifilaments are arranged into a secondary composite rod with a cross-section of a regular hexagon. The number of primary multifilaments on each side of the secondary composite rod is 13. The secondary composite rod is then drawn into secondary multifilaments. The hexagonal side dimension of the secondary multifilaments is 0.78mm. The secondary multifilaments are cut to a fixed length and arranged into screen panel segments.

[0127] (4) Hot melt pressing: The screen panel segment is placed in the hot melt pressing furnace and hot melt pressing is carried out according to the designed compression ratio of the panel segment before and after hot melt pressing. After hot melt pressing under high temperature and pressure, the fiber optic image converter blank panel segment is obtained.

[0128] (5) Twist forming: After the hot-melt press forming of the fiber optic image converter blank, the blank is rolled, cut, ground and hexagonal processed to prepare the fiber optic image converter blank. The fiber optic image converter blank is then twisted at a 180° angle in a twist forming furnace to obtain a fiber optic image converter compatible with black and white display.

[0129] The fabricated fiber optic image reversor compatible with monochrome displays has a unit fiber diameter of 2.98 μm and a center resolution of 203 lp / mm. It exhibits excellent fixed pattern noise performance at a distance of 0.1 mm from the blade edge and no obvious multifilament boundary is observed under a 10x microscope. The collimated light transmittance is >70% in the wavelength range of 380-780 nm, and the transmittance uniformity is <0.5%.

[0130] 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 method for fabricating a fiber optic image reverser compatible with monochrome displays, characterized in that, Includes the following steps: (1) Drawing of light-absorbing filaments and monofilaments: A light-absorbing glass material used in fiber optic image converters compatible with black and white displays is drawn into light-absorbing filaments; a low-refractive-index sheath glass tube is matched with a high-refractive-index core glass rod and then drawn into monofilaments; (2) Drawing of primary multifilament: The drawn monofilaments are arranged into a primary composite rod with a cross-section of a regular hexagon, and the light-absorbing filaments are evenly filled into the triangular holes of the primary composite rod. The primary composite rod assembled above is then drawn into a primary multifilament. (3) Drawing of secondary multifilament: The drawn primary multifilament is arranged into a secondary composite rod with a cross-section of a regular hexagon. The secondary composite rod is then drawn into secondary multifilament. The secondary multifilament is cut to a fixed length and arranged into a panel segment. (4) Hot melt pressing: The screen panel segment is placed in the hot melt pressing furnace and hot melt pressing is carried out according to the designed compression ratio of the panel segment before and after hot melt pressing. After hot melt pressing under high temperature and pressure, the fiber optic image converter blank panel segment is obtained. (5) Twist forming: After the hot melt pressing formed fiber optic image converter blank is rolled, cut, ground and hexagonally processed to prepare fiber optic image converter blank, the fiber optic image converter blank is twisted at a 180° angle in a twist forming furnace to prepare a fiber optic image converter compatible with black and white display. The composition of the light-absorbing glass for a fiber optic image converter compatible with monochrome displays comprises the following components in molar percentage: SiO2 68-78%, B2O3 2-10%, Al2O3 1-9%, Na2O 1-10%, K2O 3-10%, MgO 0.1-1.5%, CaO 0.1-3.0%, SrO 0.1-0.5%, NiO 0.1-1.5%, Co2O3 0.1-1.2%, MnO2 0.1-0.8%, Nd2O3 0.1-0.8%; The total content of colorants NiO, Co2O3, MnO2, and Nd2O3 in the light-absorbing glass is no more than 2.0 mol.%; 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. －7 / ℃; no crystallization occurs when held at 850℃ for 6 hours.

2. The preparation method according to claim 1, characterized in that, The diameter of the light-absorbing filament is Φ0.58-0.74mm; the number of inserted light-absorbing filaments is 6N, where 2≤N≤5; In the primary composite rod, the diameter of the monofilament is Φ3.8mm~4.8mm, and the number of monofilaments on each side is 6; the number of primary multifilaments on each side of the secondary composite rod is 10~15, the hexagonal side dimension of the primary multifilament is 1.51mm~1.80mm, and the hexagonal side dimension of the secondary multifilament is 0.60~0.89mm.

3. The preparation method according to claim 1, characterized in that, The composition of the light-absorbing glass for a fiber optic image converter compatible with monochrome displays comprises the following components in molar percentage: SiO2 70-76%, B2O3 3.5-8%, Al2O3 1.5-8%, Na2O 3.5-8%, K2O 4.5-9%, MgO 0.1-0.9%, CaO 0.5-2.5%, SrO 0.1-0.2%, NiO 0.2-0.8%, Co2O3 0.3-0.9%, MnO2 0.1-0.5%, and Nd2O3 0.2-0.8%.

4. The preparation method according to claim 3, characterized in that, The composition of the light-absorbing glass comprises the following components in molar percentage: SiO2 73.1%, B2O3 5.6%, Al2O3 4.8%, Na2O 5.8%, K2O 6.6%, MgO 0.5%, CaO 1.6%, SrO 0.1%, NiO 0.2%, Co2O3 0.6%, MnO2 0.3%, and Nd2O3 0.8%.

5. The preparation method according to any one of claims 1-4, characterized in that, The method for preparing the light-absorbing glass for a fiber optic image inverter compatible with monochrome displays includes the following steps: (1) Raw material preparation: Mix the raw materials evenly according to the proportion of the composition 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.

6. The preparation method according to claim 5, characterized in that, The first preset temperature is 1500-1560℃, and the melting time is 4-8 hours; 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. The second preset temperature is 1420-1480℃; the annealing temperature is 560-600℃, and the annealing time is 24-36 hours.

7. A fiber optic image reverser compatible with monochrome displays, characterized in that, It is prepared according to the preparation method according to any one of claims 1-6.

8. The fiber optic image reverser compatible with monochrome displays according to claim 7, characterized in that, The fiber optic image reversor compatible with monochrome displays has a unit fiber diameter ≤3.0μm, a center resolution >190lp / mm, crosstalk at 0.1mm from the blade edge <1.0%, and no obvious multifilament boundary observed under a 10x microscope; collimated light transmittance >70% in the wavelength range of 380-780nm, and transmittance uniformity <0.5%.

9. The application of the fiber optic image inverter compatible with black and white displays as described in claim 7 or 8 in a low-light image intensifier.

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