Optical fiber image inverter compatible with black and white display as well as preparation method and application of optical fiber image inverter

Abstract

The invention relates to an optical fiber image inverter compatible with black and white display and a preparation method and application thereof. The preparation method comprises the following steps: drawing a light absorption wire and a monofilament: drawing light absorption material glass of the optical fiber image inverter compatible with black and white display into the light absorption wire; drawing a secondary multifilament; carrying out hot melt pressing molding; twisting and forming; and the optical fiber image inverter compatible with black and white display is prepared. The optical fiber image inverter compatible with black and white display has the advantages of high resolution, high contrast ratio, clear imaging, uniform transmittance, excellent internal quality and the like, and can effectively improve the observation definition and resolution of a low-light image tube when being applied to a low-light image intensifier; the product can meet the matching requirements of the low-light night vision industry, can replace a traditional optical fiber image inverter product, and improves the comprehensive use performance.

Description

Technical Field

[0001] The present invention relates to the field of fiber optic image inverter manufacturing, and in particular to a fiber optic image inverter compatible with black and white display, and a preparation method and application thereof. Background Art

[0002] "Low-light" refers generally to weak light or light too low in energy to be seen at night or in low illumination. Low-light-level 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 illumination. Low-light-level night vision devices utilize low-brightness natural light—such as skylight, starlight, moonlight, and airglow—reflected by nighttime targets. These light is amplified tens of thousands of times by a low-light image intensifier, achieving a level of illumination suitable for nighttime observation by the naked eye. In other words, they utilize nighttime light to operate, effectively concealing themselves and engaging the enemy. Like telescopes and microscopes, low-light-level night vision devices are visual aids for the human eye. They enhance images that are unclear or invisible at night or in darkness to images visible to the adult eye, enabling humans to see clearly as clearly as in daylight. Low-light-level image intensifiers expand the temporal and spatial range of human activity and the ability to acquire information and images. In the absence of artificial lighting, these devices extend human activity from daytime to nighttime and from brightly lit environments to darkened conditions.

[0003] As the core component of low-light-level night vision devices, low-light-level image intensifiers are widely used in many fields such as military, criminal investigation, aerospace, and medical treatment. Its working principle is to convert weak optical images through photoelectric conversion of photocathode, electrical signal amplification of electron multiplier device and electro-optical conversion of fluorescent screen, which can convert targets with weak illumination or extremely low illumination that cannot be recognized by human eyes into visible light images that are easy to identify, with brightness increased by 10 4times or more. As the image output terminal of a low-light-level image intensifier, the phosphor screen's performance is directly related to image brightness, image detail reproduction, and the quality of image coupling transmission. It is one of the main components of an image intensifier, primarily converting an electrical image into an optical image. Therefore, the luminescence performance of the image intensifier's phosphor screen is closely related to the performance of the low-light-level image intensifier. This performance is primarily determined by the screen substrate, phosphor properties, and the screen manufacturing process. Different phosphor types directly affect image output performance, including image brightness, image detail, and field of view intensity. Commonly used phosphors in low-light-level image intensifiers include the yellow-green (green)-emitting P20 ((Zn,Cd)S:Ag), P22 (ZnS:Cu,Al), P31 (ZnS:Cu), and P43 (Gd2O2S:Tb) phosphors, as well as the white-emitting P45 (Y2O2S:Tb) phosphor. Because low-light-level image intensifiers are used in direct-view optical systems, the luminescence spectrum of the image intensifier's phosphor screen, which serves as the image output, must be well-suited to the human eye. Commonly used phosphors such as P20, P22, P31, and P43 have a peak wavelength around 540nm, emitting yellow-green light. While this yellow-green wavelength is the most sensitive to the human eye, it can be irritating and easily lead to visual fatigue after prolonged viewing. The most comfortable viewing experience for the human eye is achieved with the black-and-white P45 phosphor. This black-and-white display's spectral response wavelengths are mostly within the human eye's comfort zone, providing both sensitivity and comfort. This is because the human eye is more sensitive to black-and-white contrast than to color resolution in low-light conditions. Black-and-white displays can convert weak light signals into clear black-and-white images, making them easier for the human eye to discern and distinguish image details. For example, during military night reconnaissance missions, when soldiers observe targets through a low-light-level image intensifier, black-and-white images clearly display key information such as the target's outline and position, without the interference from color that can hinder visual recognition. Furthermore, black-and-white displays offer a fast response speed. In low-light environments, where light changes rapidly, a fast response ensures that the screen captures and displays changes in light signals promptly, avoiding image smearing. During nighttime investigations at criminal investigation scenes, the fast-responding black-and-white display can clearly record suspicious clues that appear instantly, providing critical visual evidence for solving cases. Furthermore, black-and-white displays are relatively inexpensive to manufacture and offer high stability. When applied on a large scale to various low-light imaging devices, the cost advantage is significant, while high stability ensures reliable, long-term operation in complex environments. Low-light detection equipment, such as those in the aerospace sector, places extremely high demands on device stability, making the stable performance of black-and-white displays an ideal choice.

[0004] Fiber optic image invertors are core optical components in low-light-level night vision devices. They play a key role in the imaging system of low-light-level image intensifiers, serving as the optical output window. They can invert images 180° for transmission. They offer advantages such as a large numerical aperture, high light transmission efficiency, high resolution, clear transmission, optically zero thickness, simple structure, compact size, and light weight. They can effectively replace the relay lens system in low-light-level night vision devices, playing a vital role in improving the quality of imaging devices. They are a cutting-edge, high-tech product in the global optoelectronics industry. Black-and-white low-light-level night vision technology places high demands on fiber optic image invertors. These invertors must not only have high clarity (both resolution and contrast) but also be perfectly compatible with the phosphors used in black-and-white displays. However, existing fiber optic image invertors face several pressing challenges when used with black-and-white fluorescent screens. On the one hand, the materials used in traditional 6μm or 4μm fiber optic image intensifiers are not compatible with black and white fluorescent screens, making them difficult to meet the imaging requirements of black and white displays. This results in information loss and reduced contrast during image transmission, making the final image unclear and affecting the human eye's observation effect. On the other hand, in low-light environments, to ensure comfortable observation for the human eye, the image needs to have sufficient clarity and an appropriate brightness range. However, existing fiber optic image intensifiers, especially when working in conjunction with black and white fluorescent screens, have difficulty fully meeting these requirements in terms of imaging quality, limiting the performance of low-light image intensifiers in practical applications.

[0005] The image transmission mechanism of the fiber optic image inverter is realized by utilizing the total internal reflection principle of the optical fiber. The optical fiber that constitutes the fiber optic image inverter is made of a low-refractive index skin glass tube, a high-refractive index core glass rod and a light-absorbing glass yarn, which are prepared by hot melting and pressing through a rod-tube combination and a vacuum drawing process. Since the optical fiber is completely tightly fused together by the skin glass, the adjacent optical fibers are close to each other, resulting in crosstalk between adjacent optical fibers. For example, due to the uneven temperature field or uneven drawing force during the preparation process, the wall thickness of the skin glass tube may be uneven, which will cause the input light to penetrate the skin during the total internal reflection, resulting in light leakage. Or, the total internal reflection conditions of the light are destroyed due to defects or contaminants at the contact interface between the glass or skin glass of the optical fiber, causing the light to be scattered here. These scattered lights enter the adjacent optical fibers and also cause crosstalk. Crosstalk is an important factor that directly affects the imaging quality such as contrast and clarity of the fiber optic image inverter.

[0006] To address the challenges of light crosstalk and light leakage between optical fibers in fiber optic image inverters, light-absorbing glass filaments are typically filled in the gaps between adjacent optical fibers to absorb stray light and reduce crosstalk. Inserting light-absorbing glass filaments can effectively eliminate stray light. Light-absorbing glass is drawn into absorbing filaments and inserted into the gaps between arranged optical fibers to absorb light crosstalk and light leakage. However, this does not completely achieve optical insulation, as the key issue lies in the transmittance of the light-absorbing glass. The function of light-absorbing glass is to absorb stray light that penetrates the cortex of the optical fiber 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 enhance the clarity, contrast, and other performance 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, black and white display compatible fiber optic image inverters. Therefore, the light absorption effect of the light-absorbing glass is also 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 to near-infrared bands, to achieve 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 between the light-absorbing glass and the low-refractive-index cortex glass in the optical fiber imaging element, different degrees of ion diffusion and mutual penetration are inevitable during the thermal processing. In addition, since the optical fiber image inverter in the optical fiber imaging element also adds a thermal twisting process, the degree of ion diffusion and mutual penetration of the two components at the contact interface between the glass material and the cortex material is more serious than that of the optical fiber panel, resulting in a certain degree of decline in the transmission characteristics of the optical fiber image inverter such as transmittance and contrast.

[0008] Ordinary light-absorbing glass still has a high transmittance in the visible light range at a thickness of 0.5mm. As the thickness decreases, the transmittance will gradually increase. However, the light-absorbing materials of traditional fiber optic image inverters generally have 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 black and white display compatible fiber optic image inverters cannot meet the application requirements of high definition, high contrast, and black and white display compatibility. Summary of the Invention

[0009] In response to the above-mentioned problems of the prior art, the present invention provides a fiber optic image inverter compatible with black and white display and a preparation method thereof. The fiber optic image inverter can match the low-light-level night vision technology of black and white display, and can have perfect compatibility and adaptability with the phosphor of black and white display, meeting the requirements of high-definition imaging of black and white display.

[0010] In order to achieve the above object, the technical solution adopted by the present invention is:

[0011] A method for preparing a fiber optic image inverter compatible with black and white display comprises the following steps:

[0012] (1) Drawing of light-absorbing filaments and monofilaments: Drawing a light-absorbing glass material used for an optical fiber image inverter compatible with black and white display into a light-absorbing filament; matching a low-refractive-index skin glass tube with a high-refractive-index core glass rod and then drawing it into a monofilament;

[0013] (2) Drawing of a primary multifilament: Arranging the drawn monofilaments into a primary composite rod with a regular hexagonal cross section, and uniformly filling the triangular pores of the primary composite rod with the light-absorbing filaments; and drawing the primary composite rod thus assembled into a primary multifilament;

[0014] (3) Drawing of secondary multifilaments: Arranging the drawn primary multifilaments into secondary composite rods with a regular hexagonal cross section, and then drawing the secondary composite rods into secondary multifilaments, cutting the secondary multifilaments to a fixed length and arranging them into screen plate segments;

[0015] (4) Hot melt pressing: placing the screen plate segment into a hot melt pressing furnace, hot melt pressing is performed according to the designed plate segment compression ratio before and after hot melt pressing, and hot melt pressing is performed under high temperature and pressure to obtain the fiber optic image invertor blank segment;

[0016] (5) Twisting molding: The fiber optic image inverter blank plate segment after hot melt pressing is subjected to rounding, cutting, grinding, and hexagonal processing to prepare a fiber optic image inverter blank. The fiber optic image inverter blank is twisted at an angle of 180° in a twisting molding furnace to prepare a fiber optic image inverter compatible with black and white display;

[0017] The composition of the light absorbing glass for an optical fiber image inverter compatible with black and white display includes 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 wire is Φ0.58-0.74 mm; the number of inserted wires of the light absorbing wire is 6N, where 2≤N≤5.

[0019] In the primary composite rod, the wire 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, and the hexagonal opposite side size of the primary multifilaments is 1.51mm~1.80mm; the hexagonal opposite side size of the secondary multifilaments is 0.60~0.89mm.

[0020] The fiber diameter of the optical fiber image inverter prepared in the method and compatible with black and white display is ≤3.0 μm.

[0021] The composition of the light absorbing glass for the optical fiber image inverter compatible with black and white display preferably includes the following components in molar percentage: SiO2 70-76%, B2O3 3.5-8%, Al2O3 1.5-8%, Na2O3.5-8%, 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 an optical fiber image inverter compatible with black and white display more preferably includes the following components in molar percentage: SiO2 73.1%, B2O3 5.6%, Al2O3 4.8%, Na2O5.8%, 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 material glass for the optical fiber image inverter compatible with black and white display comprises the following steps:

[0024] (1) Raw material preparation: the raw materials are mixed uniformly according to the composition ratio to obtain a raw material mixture;

[0025] (2) Glass melting: adding the raw material mixture into a crucible and melting it at a first preset temperature. After the raw material mixture is melted, stirring is performed to make the components fully and evenly melt until a clear and homogenized glass liquid is formed. Then, the raw material mixture is discharged at a second preset temperature and cast into the required glass in a mold to form a preliminary glass structure. After the glass is cooled and solidified, annealing is performed to obtain a light absorbing material glass blank for an optical fiber imaging element.

[0026] (3) Blank processing: The annealed and cooled light-absorbing glass blank is cut, ground, and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements for the preparation of optical fiber imaging components and the optical matching requirements with the P45 phosphor.

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

[0028] The stirring is performed 2-3 times, the rotation speed of each stirring is 150-180 rpm, and the stirring time is 0.5-1 hour.

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

[0030] The present invention is based on the existing light-absorbing material glass. By improving the colorant composition ratio to enhance the light absorption effect and light transmission performance of the light-absorbing material glass, the ion diffusion and mutual penetration between the two components of the light-absorbing material glass and the cortex glass are reduced, and the preparation technology is optimized. The light-absorbing material glass of the present invention is applied to the optical fiber image inverter, which can effectively improve the imaging contrast and clarity of the optical fiber image inverter. The prepared optical fiber image inverter has the advantages of high resolution, high contrast, high transmittance and high uniformity, and is particularly suitable for optical fiber image inverter products compatible with black and white displays.

[0031] The total content of the colorants NiO, Co2O3, MnO2, and Nd2O3 in the light absorbing glass is no more than 2.0 mol%. The light absorbing glass for the optical fiber image invertor compatible with black and white display has a spectral transmittance of more than 70% in the ultraviolet wavelength range of 300-400 nm and a spectral transmittance of less than 2.0% in the visible wavelength range of 580-670 nm at a thickness of 0.30±0.01 mm. The thermal expansion coefficient at 30-300°C is (77±2)×10 －7 / ℃; no crystallization occurs when kept at 850℃ for 6 hours.

[0032] The present invention further provides an optical fiber image inverter compatible with black and white display, which is prepared according to the preparation method.

[0033] The fiber optic image inverter compatible with black and white display has a unit fiber diameter of ≤3.0μm and a central resolution of >190lp / mm; crosstalk is less than <1.0% at a distance of 0.1mm from the blade, has excellent fixed pattern noise performance, and has no obvious multifilament boundaries when observed under a 10x microscope; the collimated light transmittance within the wavelength range of 380-780nm is >70%, and the transmittance uniformity is <0.5%.

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

[0035] Compared with the prior art, the optical fiber image invertor compatible with black and white display of the present invention has the following advantages:

[0036] (1) The fiber optic image inverter of the present invention, through special optical structure design and material control, enables the light absorbing glass material to achieve high transmittance in the ultraviolet band, thereby enabling the fiber optic image inverter and the black and white fluorescent display to work better together, the transmission of light signals between the two is more efficient, and the luminous uniformity 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 invertor compatible with black and white displays of the present invention can effectively reduce the transmittance of the visible light band by optimizing the composition of the core light-absorbing glass material, thereby effectively reducing the crosstalk phenomenon between optical fibers and improving the contrast and clarity of imaging. By using less light-absorbing filaments, the crosstalk can be achieved at a distance of 0.1 mm from the blade edge.

[0038] (3) The fiber optic image invertor of the present invention, which is compatible with black and white displays, has high resolution, with a unit fiber diameter of ≤3.0 μm and a central resolution greater than 190 lp / mm, which is significantly improved compared to the existing technology;

[0039] (4) The fiber optic image invertor of the present invention, which is compatible with black and white displays, has high transmittance and transmittance uniformity. In the wavelength range of 380-780 nm, the collimated light transmittance is greater than 70%, and the transmittance uniformity is less than 0.5%;

[0040] (5) The fiber optic image invertor compatible with black and white display of the present 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 the improved compatibility with black and white fluorescent displays, the fiber optic image invertor of the present invention makes the image output by the low-light-level image intensifier more suitable for human observation in terms of brightness, contrast and color reproduction. In a low-light environment, the human eye can more easily and comfortably identify image details, reduce visual fatigue, and improve the practicality of the low-light-level image intensifier in actual applications.

[0042] The fiber optic image inverter compatible with black and white display of the present invention has the advantages of high resolution, high contrast, clear imaging, uniform transmittance, and excellent internal quality. The fiber optic image inverter compatible with black and white display of the present invention is used in a low-light-level image intensifier, which can effectively improve the observation clarity and resolution of the low-light-level image tube. The product can meet the supporting needs of the low-light-level night vision industry, and can also replace traditional fiber optic image inverter products, improve comprehensive use performance, and promote the development of optoelectronic devices in related fields such as space visual measurement and detection imaging towards high performance and wide field of view, and has a good application and promotion prospect.

[0043] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A contrast test chart of the optical fiber image inverter provided by an embodiment of the present invention;

[0045] Figure 2 This is the transmittance curve of the light-absorbing glass provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0046] To further illustrate the technical means and effects employed by the present invention to achieve its intended objectives, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention is provided in conjunction with preferred embodiments. However, this description is not intended to limit the present invention. In the following description, different references to "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics of one or more embodiments may be combined in any suitable manner.

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

[0048]

[0049] See also Figure 1 , which is a contrast test chart of the optical fiber image inverter compatible with black and white display provided by an embodiment of the present invention. It can be seen that the crosstalk at a distance of 0.1 mm from the blade has an effect of less than 1.0%.

[0050] See also Figure 2 , which is the transmittance curve of the light-absorbing material glass. It can be seen that when the total content of the colorants NiO, Co2O3, MnO2, and Nd2O3 in the light-absorbing material glass selected in the present invention is not greater than 2.0 mol%. At a thickness of 0.3±0.01 mm, the light-absorbing material glass has strong light absorption and filtering effects within the wavelength range of 580-670 nm in the visible light band, with a spectral transmittance of less than 2.0%, indicating a very significant light absorption effect on visible light. At a thickness of 0.3±0.01 mm, the light-absorbing material glass has a relatively high transmittance within the wavelength range of 300-400 nm in the ultraviolet band, with a spectral transmittance of greater than 70%, indicating a very significant light transmittance effect on the ultraviolet band.

[0051] Herein, all "mol. %" are based on the total molar amount of the final glass composition. The glass chemical composition (mol. %) of the examples is detailed in Table 1.

[0052] The parameters, measuring methods and instruments for the light absorbing glass of the present invention are as follows:

[0053] (1) The transmittance of the light absorbing glass is measured 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 and the method specified in GB / T 16920-2015.

[0055] Example 1

[0056] A method for preparing a fiber optic image inverter compatible with black and white display comprises the following steps:

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

[0058] a. Prepare light absorbing glass;

[0059] Select raw materials according to the glass composition of Example 1 in Table 1 so that the ingredients meet the glass chemical composition of Table 1, and then prepare the light absorbing material glass according to the following steps:

[0060] (1) Raw material preparation: weigh raw materials quartz sand, boric acid, aluminum oxide, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide according to a molar ratio, mix them uniformly, and obtain a raw material mixture;

[0061] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1500°C for 8 hours. After the raw material mixture is melted, it is stirred twice, each stirring speed is 150 rpm, and the stirring time is 1 hour to ensure that all components are fully and evenly melted until a clear and homogenized glass liquid is formed. The material is then discharged at 1420°C and cast into the required glass in a mold to form a preliminary glass structure. After the glass cools and solidifies, it is annealed at 600°C for 24 hours. Thus, a light absorbing material glass blank for optical fiber imaging elements is obtained.

[0062] (3) Blank processing: The annealed and cooled light-absorbing glass blank is cut, ground, and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements for the preparation of optical fiber imaging components and the optical matching requirements with the P45 phosphor.

[0063] b. Drawing the light-absorbing glass with good surface processing into a light-absorbing wire with a wire diameter of 0.74 mm;

[0064] c. Match the low-refractive-index skin glass tube with the high-refractive-index core glass rod and draw them into a monofilament with a diameter of Φ4.8mm;

[0065] (2) Drawing of primary multifilaments: Arrange the drawn monofilaments into a primary composite rod with a regular hexagonal cross section, with 6 monofilaments on each side, and uniformly insert the light-absorbing filaments into the triangular pores of the primary composite rod. The number of inserted light-absorbing filaments is 24, and draw the primary composite rod into a primary multifilament. The hexagonal opposite side size of the primary multifilament is 1.8 mm.

[0066] (3) Drawing of secondary multifilaments: Arrange the drawn primary multifilaments into a secondary composite rod with a regular hexagonal cross section, wherein each side of the secondary composite rod has 10 primary multifilaments. The secondary composite rod is then drawn into secondary multifilaments, wherein the hexagonal opposite side dimension of the secondary multifilaments is 0.60 mm. The secondary multifilaments are cut to a fixed length and arranged into screen plate segments.

[0067] (4) Hot melt pressing: placing the screen plate segment into a hot melt pressing furnace, hot melt pressing is performed according to the designed plate segment compression ratio before and after hot melt pressing, and hot melt pressing is performed under high temperature and pressure to obtain the fiber optic image invertor blank segment;

[0068] (5) Twisting molding: The fiber optic image inverter blank plate segment formed by hot melt pressing is subjected to rounding, cutting, grinding, and hexagonal processing to prepare a fiber optic image inverter blank. The fiber optic image inverter blank is twisted at an angle of 180° in a twisting molding furnace to prepare a fiber optic image inverter compatible with black and white display.

[0069] The unit fiber diameter of the prepared optical fiber image inverter compatible with black and white display is 2.97 μm, the central resolution is 203 lp / mm; the crosstalk is 0.91% at a distance of 0.1 mm from the knife edge, and it has excellent fixed pattern noise performance. There is no obvious multifilament boundary when observed under a 10x microscope; the collimated light transmittance is greater than 70% in the wavelength range of 380-780 nm, and the transmittance uniformity is less than 0.5%.

[0070] Example 2

[0071] A method for preparing a fiber optic image inverter compatible with black and white display comprises the following steps:

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

[0073] a. Prepare light absorbing glass;

[0074] Select raw materials according to the glass composition of Example 2 in Table 1 so that the ingredients meet the glass chemical composition of Table 1, and then prepare the light absorbing material glass according to the following steps:

[0075] (1) Raw material preparation: weigh raw materials quartz sand, boric acid, aluminum oxide, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide according to a molar ratio, mix them uniformly, and obtain a raw material mixture;

[0076] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1560°C for 4 hours. After the raw material mixture is melted, it is stirred three times, each stirring speed is 180 rpm, and the stirring time is 0.5 hours to ensure that all components are fully and evenly melted until a clear and homogenized glass liquid is formed. The material is then discharged at 1480°C and cast into the required glass in a mold to form a preliminary glass structure. After the glass is cooled and solidified, it is annealed at 560°C for 36 hours. Thus, a light absorbing material glass blank for optical fiber imaging elements is obtained.

[0077] (3) Blank processing: The annealed and cooled light-absorbing glass blank is cut, ground, and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements for the preparation of optical fiber imaging components and the optical matching requirements with the P45 phosphor.

[0078] b. Drawing the light-absorbing glass with good surface processing into a light-absorbing wire with a wire diameter of 0.62 mm;

[0079] c. Match the low-refractive-index skin glass tube with the high-refractive-index core glass rod and draw them into a monofilament with a diameter of Φ4.1mm;

[0080] (2) Drawing of a primary multifilament: Arrange the drawn monofilaments into a primary composite rod with a regular hexagonal cross section, with 6 monofilaments on each side, and uniformly insert the light-absorbing filaments into the triangular pores of the primary composite rod. The number of inserted light-absorbing filaments is 24, and draw the primary composite rod into a primary multifilament. The hexagonal opposite side size of the primary multifilament is 1.6 mm.

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

[0082] (4) Hot melt pressing: placing the screen plate segment into a hot melt pressing furnace, hot melt pressing is performed according to the designed plate segment compression ratio before and after hot melt pressing, and hot melt pressing is performed under high temperature and pressure to obtain the fiber optic image invertor blank segment;

[0083] (5) Twisting molding: The fiber optic image inverter blank plate segment formed by hot melt pressing is subjected to rounding, cutting, grinding, and hexagonal processing to prepare a fiber optic image inverter blank. The fiber optic image inverter blank is twisted at an angle of 180° in a twisting molding furnace to prepare a fiber optic image inverter compatible with black and white display.

[0084] The unit fiber diameter of the prepared optical fiber image inverter compatible with black and white display is 2.98 μm, the central resolution is 203 lp / mm; the crosstalk is 0.93% at a distance of 0.1 mm from the knife edge, it has excellent fixed pattern noise performance, and no obvious multifilament boundaries are observed under a 10x microscope; the collimated light transmittance is greater than 70% in the wavelength range of 380-780 nm, and the transmittance uniformity is less than 0.5%.

[0085] Example 3

[0086] A method for preparing a fiber optic image inverter compatible with black and white display comprises the following steps:

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

[0088] a. Prepare light absorbing glass;

[0089] Select raw materials according to the glass composition of Example 3 in Table 1 so that the ingredients meet the glass chemical composition of Table 1, and then prepare the light absorbing material glass according to the following steps:

[0090] (1) Raw material preparation: weigh raw materials quartz sand, boric acid, aluminum oxide, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide according to a molar ratio, mix them uniformly, and obtain a raw material mixture;

[0091] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1550°C for 6 hours. After the raw material mixture is melted, it is stirred twice, each stirring speed is 160 rpm, and the stirring time is 0.5 hours to ensure that all components are fully and evenly melted until a clear and homogenized glass liquid is formed. The material is then discharged at 1430°C and cast into the required glass in a mold to form a preliminary glass structure. After the glass cools and solidifies, it is annealed at 580°C for 28 hours. Thus, a light absorbing material glass blank for optical fiber imaging elements is obtained.

[0092] (3) Blank processing: The annealed and cooled light-absorbing glass blank is cut, ground, and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements for the preparation of optical fiber imaging components and the optical matching requirements with the P45 phosphor.

[0093] b. Drawing the light-absorbing glass with good surface processing into a light-absorbing wire with a wire diameter of 0.58 mm;

[0094] c. Match the low-refractive-index skin glass tube with the high-refractive-index core glass rod and draw them into a monofilament with a diameter of Φ3.8mm;

[0095] (2) Drawing of a primary multifilament: Arrange the drawn monofilaments into a primary composite rod with a regular hexagonal cross section, with 6 monofilaments on each side, and uniformly insert the light-absorbing filaments into the triangular pores of the primary composite rod. The number of inserted light-absorbing filaments is 30, and draw the primary composite rod into a primary multifilament. The hexagonal opposite side dimension of the primary multifilament is 1.51 mm.

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

[0097] (4) Hot melt pressing: placing the screen plate segment into a hot melt pressing furnace, hot melt pressing is performed according to the designed plate segment compression ratio before and after hot melt pressing, and hot melt pressing is performed under high temperature and pressure to obtain the fiber optic image invertor blank segment;

[0098] (5) Twisting molding: The fiber optic image inverter blank plate segment formed by hot melt pressing is subjected to rounding, cutting, grinding, and hexagonal processing to prepare a fiber optic image inverter blank. The fiber optic image inverter blank is twisted at an angle of 180° in a twisting molding furnace to prepare a fiber optic image inverter compatible with black and white display.

[0099] The unit fiber diameter of the prepared optical fiber image inverter compatible with black and white display is 2.94 μm, the central resolution is 203 lp / mm; the crosstalk is 0.92% at a distance of 0.1 mm from the knife edge, it has excellent fixed pattern noise performance, and there is no obvious multifilament boundary when observed under a 10x microscope; the collimated light transmittance within the wavelength range of 380-780 nm is greater than 70%, and the transmittance uniformity is less than 0.5%.

[0100] Example 4

[0101] A method for preparing a fiber optic image inverter compatible with black and white display comprises the following steps:

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

[0103] a. Prepare light absorbing glass;

[0104] Select raw materials according to the glass composition of Example 4 in Table 1 so that the ingredients meet the glass chemical composition of Table 1, and then prepare the light absorbing material glass according to the following steps:

[0105] (1) Raw material preparation: weigh raw materials quartz sand, boric acid, aluminum oxide, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide according to a molar ratio, mix them uniformly, and obtain a raw material mixture;

[0106] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1540°C for 7 hours. After the raw material mixture is melted, it is stirred three times, each stirring speed is 150 rpm, and the stirring time is 1 hour to ensure that all components are fully and evenly melted until a clear and homogenized glass liquid is formed. The material is then discharged at 1450°C and cast into the required glass in a mold to form a preliminary glass structure. After the glass cools and solidifies, it is annealed at 570°C for 26 hours. Thus, a light absorbing material glass blank for optical fiber imaging elements is obtained.

[0107] (3) Blank processing: The annealed and cooled light-absorbing glass blank is cut, ground, and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements for the preparation of optical fiber imaging components and the optical matching requirements with the P45 phosphor.

[0108] b. Drawing the light-absorbing glass with good surface processing into a light-absorbing wire with a wire diameter of 0.70 mm;

[0109] c. Match the low-refractive-index skin glass tube with the high-refractive-index core glass rod and draw them into a monofilament with a diameter of Φ4.6mm;

[0110] (2) Drawing of a primary multifilament: Arrange the drawn monofilaments into a primary composite rod with a regular hexagonal cross section, with 6 monofilaments on each side, and uniformly insert the light-absorbing filaments into the triangular pores of the primary composite rod. The number of inserted light-absorbing filaments is 18, and draw the primary composite rod into a primary multifilament. The hexagonal opposite side size of the primary multifilament is 1.7 mm.

[0111] (3) Drawing of secondary multifilaments: Arranging the drawn primary multifilaments into a secondary composite rod with a regular hexagonal cross section, wherein each side of the secondary composite rod has 13 primary multifilaments, and then drawing the secondary composite rod into secondary multifilaments, wherein the hexagonal opposite side dimension of the secondary multifilaments is 0.77 mm, and then cutting the secondary multifilaments into fixed lengths and arranging them into screen panel segments;

[0112] (4) Hot melt pressing: placing the screen plate segment into a hot melt pressing furnace, hot melt pressing is performed according to the designed plate segment compression ratio before and after hot melt pressing, and hot melt pressing is performed under high temperature and pressure to obtain the fiber optic image invertor blank segment;

[0113] (5) Twisting molding: The fiber optic image inverter blank plate segment formed by hot melt pressing is subjected to rounding, cutting, grinding, and hexagonal processing to prepare a fiber optic image inverter blank. The fiber optic image inverter blank is twisted at an angle of 180° in a twisting molding furnace to prepare a fiber optic image inverter compatible with black and white display.

[0114] The unit fiber diameter of the prepared optical fiber image inverter compatible with black and white display is 2.94 μm, the central resolution is 203 lp / mm; the crosstalk is 0.95% at a distance of 0.1 mm from the knife edge, it has excellent fixed pattern noise performance, and there is no obvious multifilament boundary when observed under a 10x microscope; the collimated light transmittance within the wavelength range of 380-780 nm is greater than 70%, and the transmittance uniformity is less than 0.5%.

[0115] Example 5

[0116] A method for preparing a fiber optic image inverter compatible with black and white display comprises the following steps:

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

[0118] a. Prepare light absorbing glass;

[0119] Select raw materials according to the glass composition of Example 5 in Table 1 so that the ingredients meet the glass chemical composition of Table 1, and then prepare the light absorbing material glass according to the following steps:

[0120] (1) Raw material preparation: weigh raw materials quartz sand, boric acid, aluminum oxide, sodium carbonate, potassium carbonate, basic magnesium carbonate, calcium carbonate, strontium carbonate, nickel oxide, cobalt oxide, manganese dioxide and neodymium oxide according to a molar ratio, mix them uniformly, and obtain a raw material mixture;

[0121] (2) Glass melting: The raw material mixture is added to a crucible and melted at 1530°C for 8 hours. After the raw material mixture is melted, it is stirred twice, each stirring speed is 170 rpm, and the stirring time is 0.5 hours to ensure that all components are fully and evenly melted until a clear and homogenized glass liquid is formed. The material is then discharged at 1460°C and cast into the required glass in a mold to form a preliminary glass structure. After the glass cools and solidifies, it is annealed at 590°C for 27 hours. Thus, a light absorbing material glass blank for optical fiber imaging elements is obtained.

[0122] (3) Blank processing: The annealed and cooled light-absorbing glass blank is cut, ground, and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements for the preparation of optical fiber imaging components and the optical matching requirements with the P45 phosphor.

[0123] b. Drawing the light-absorbing glass with good surface processing into a light-absorbing wire with a wire diameter of 0.64 mm;

[0124] c. Match the low-refractive-index skin glass tube with the high-refractive-index core glass rod and draw them into a monofilament with a diameter of Φ4.2mm;

[0125] (2) Drawing of a primary multifilament: Arrange the drawn monofilaments into a primary composite rod with a regular hexagonal cross section, with 6 monofilaments on each side, and uniformly insert the light-absorbing filaments into the triangular pores of the primary composite rod. The number of inserted light-absorbing filaments is 30, and draw the primary composite rod into a primary multifilament. The hexagonal opposite side size of the primary multifilament is 1.8 mm.

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

[0127] (4) Hot melt pressing: placing the screen plate segment into a hot melt pressing furnace, hot melt pressing is performed according to the designed plate segment compression ratio before and after hot melt pressing, and hot melt pressing is performed under high temperature and pressure to obtain the fiber optic image invertor blank segment;

[0128] (5) Twisting molding: The fiber optic image inverter blank plate segment formed by hot melt pressing is subjected to rounding, cutting, grinding, and hexagonal processing to prepare a fiber optic image inverter blank. The fiber optic image inverter blank is twisted at an angle of 180° in a twisting molding furnace to prepare a fiber optic image inverter compatible with black and white display.

[0129] The unit fiber diameter of the prepared optical fiber image inverter compatible with black and white display is 2.98 μm, the central resolution is 203 lp / mm; the crosstalk is 0.90% at a distance of 0.1 mm from the knife edge, it has excellent fixed pattern noise performance, and no obvious multifilament boundaries are observed under a 10x microscope; the collimated light transmittance within the wavelength range of 380-780 nm is greater than 70%, and the transmittance uniformity is less than 0.5%.

[0130] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a fiber optic image invertor compatible with black and white display, characterized in that: The following steps are involved: (1) Drawing of light-absorbing filaments and monofilaments: Drawing a light-absorbing glass material used for an optical fiber image inverter compatible with black and white display into a light-absorbing filament; matching a low-refractive-index skin glass tube with a high-refractive-index core glass rod and then drawing it into a monofilament; (2) Drawing of a primary multifilament: Arranging the drawn monofilaments into a primary composite rod with a regular hexagonal cross section, and uniformly filling the triangular pores of the primary composite rod with the light-absorbing filaments, and drawing the primary composite rod thus assembled into a primary multifilament; (3) Drawing of secondary multifilaments: Arranging the drawn primary multifilaments into secondary composite rods with a regular hexagonal cross section, and then drawing the secondary composite rods into secondary multifilaments, cutting the secondary multifilaments to a fixed length and arranging them into screen plate segments; (4) Hot melt pressing: placing the screen plate segment into a hot melt pressing furnace, hot melt pressing is performed according to the designed plate segment compression ratio before and after hot melt pressing, and hot melt pressing is performed under high temperature and pressure to obtain the fiber optic image invertor blank segment; (5) Twisting molding: The fiber optic image inverter blank plate segment after hot melt pressing is subjected to rounding, cutting, grinding, and hexagonal processing to prepare a fiber optic image inverter blank. The fiber optic image inverter blank is twisted at an angle of 180° in a twisting molding furnace to prepare a fiber optic image inverter compatible with black and white display; The composition of the light absorbing glass for an optical fiber image inverter compatible with black and white display includes 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%.

2. The preparation method according to claim 1, characterized in that The diameter of the light absorbing wire is Φ0.58-0.74 mm; the number of inserted wires of the light absorbing wire is 6N, where 2≤N≤5; In the primary composite rod, the wire 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, and the hexagonal opposite side size of the primary multifilaments is 1.51mm~1.80mm; the hexagonal opposite side size of the secondary multifilaments is 0.60~0.89mm.

3. The preparation method according to claim 1, characterized in that The composition of the light absorbing glass for an optical fiber image inverter compatible with black and white display includes 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 includes 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 to 4, characterized in that The total content of the colorants NiO, Co2O3, MnO2, and Nd2O3 in the light absorbing glass is not greater than 2.0 mol%. The light absorbing glass has a spectral transmittance greater than 70% in the ultraviolet wavelength range of 300-400 nm and a spectral transmittance less than 2.0% in the visible light wavelength range of 580-670 nm at a thickness of 0.30±0.01 mm. The thermal expansion coefficient at 30-300°C is (77±2)×10 －7 / ℃; no crystallization occurs when kept at 850℃ for 6 hours.

6. The preparation method according to claim 5, characterized in that The method for preparing the light absorbing material glass for the optical fiber image inverter compatible with black and white display comprises the following steps: (1) Raw material preparation: the raw materials are mixed uniformly according to the composition ratio to obtain a raw material mixture; (2) Glass melting: adding the raw material mixture into a crucible and melting it at a first preset temperature. After the raw material mixture is melted, stirring is performed to make the components fully and evenly melt until a clear and homogenized glass liquid is formed. Then, the raw material mixture is discharged at a second preset temperature and cast into the required glass in a mold to form a preliminary glass structure. After the glass is cooled and solidified, annealing is performed to obtain a light absorbing material glass blank for an optical fiber imaging element. (3) Blank processing: The annealed and cooled light-absorbing glass blank is cut, ground, and polished to ensure that the dimensional accuracy and surface finish of the glass meet the assembly requirements for the preparation of optical fiber imaging components and the optical matching requirements with the P45 phosphor.

7. The preparation method according to claim 6, characterized in that The first preset temperature is 1500-1560° C., and the melting time is 4-8 hours; The stirring is performed 2-3 times, the speed of each stirring is 150-180 rpm, and the stirring time is 0.5-1 hour; The second preset temperature is 1420-1480° C.; the annealing temperature is 560-600° C., and the annealing time is 24-36 hours.

8. A fiber optic image invertor compatible with black and white display, characterized in that: It is prepared according to the preparation method according to any one of claims 1 to 7.

9. The fiber optic image invertor compatible with black and white display according to claim 8, characterized in that: The unit fiber diameter of the optical fiber image inverter compatible with black and white display is ≤3.0μm, the central resolution is >190lp / mm; the crosstalk is less than <1.0% at a distance of 0.1mm from the knife edge, and there is no obvious multifilament boundary when observed under a 10x microscope; the collimated light transmittance is >70% in the wavelength range of 380-780nm, and the transmittance uniformity is <0.5%.

10. Use of the optical fiber image invertor compatible with black and white display according to claim 8 or 9 in a low-light-level image intensifier.

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