A rigid fiber bundle raw sheet and a method for manufacturing the same

Abstract

The application relates to a hard fiber bundle blank and a preparation method thereof. The hard fiber bundle blank comprises a fiber bundle; the fiber bundle is composed of a plurality of optical fibers; the optical fibers comprise a sheath; the preparation method comprises the following steps: 1) setting an etching layer and a cladding layer outside the fiber bundle to form a fusion pressure material; the etching layer is arranged between the fiber bundle and the cladding layer; the softening temperature and the thermal expansion coefficient of the sheath are higher than those of the cladding layer; 2) performing fusion pressure on the fusion pressure material, and cutting to obtain a plate segment; the fusion pressure is that the fusion pressure material is heated to 0-5 DEG C higher than the softening temperature of the cladding layer and is kept for 2-5 h, and then the fusion pressure material is heated to 2-10 DEG C higher than the softening temperature of the sheath and is kept for 2-5 h; and 3) etching the plate segment by using an etching liquid, and then cleaning, drying and obtaining the hard fiber bundle blank. The application can realize fusion pressure of irregular fiber bundles, and the obtained fiber bundles have good curvatures.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of optical fiber bundle blank preparation, in particular to a hard fiber bundle blank and a preparation method thereof. BACKGROUND

[0002] At present, the fusion pressing operation of the fiber bundle is a very mature technology, and the mechanical fusion pressing is the mainstream fusion pressing method, such as shown in FIG. 1, the method is to arrange the fibers to obtain a fiber bundle 2, then use a sliding block 1 to cover the fiber bundle 2, then place the covered fiber bundle 2 in a base, put on a sleeve, and then place it in a pit-type hot pressing furnace, heat it, apply pressure on the sleeve after heating, and the sliding block 1 rotates and slips to make the internal space shrink, and the fiber bundle 2 completes the fusion pressing under the action of the pressure. Because the outer fibers of the fiber bundle need to be in direct contact with the mold during the fusion pressing process, the outer fibers are damaged, so a fiber bundle slightly larger than the final product needs to be arranged during the arrangement, and the excess fibers are removed by a fine carving machine after the fusion pressing is completed, and finally the required product size is obtained. Figure 1 Although the above-mentioned mechanical fusion pressing method has a wide range of applications, it has certain requirements for the shape of the fiber bundle, and only the fiber bundle with a central symmetric cross-section and a flat side surface can be used, for example, a fiber bundle with a regular hexagonal or square cross-section. If the side surface of the fiber bundle is a curved surface or the cross-section of the fiber bundle is a non-central symmetric shape, for example, a cylindrical fiber bundle, when the cylindrical fiber bundle is prepared using the above-mentioned method, the fiber bundle will shrink during the fusion pressing process, and the curvature of the side surface of the cylindrical fiber bundle will change during the shrinkage process. Because the covering sliding block is made of metal, the curvature will not change during the fusion pressing process, resulting in deformation of the prepared fiber bundle; when processing a fiber bundle with an isosceles trapezoidal cross-section, the isosceles trapezoidal cross-section is a non-central symmetric structure, and after fusion pressing, deformation will still occur. If the fiber bundle after fusion pressing is deformed, as shown in FIG. 2, it will be difficult to find the center and the fiber arrangement direction when fine carving is performed on the fiber bundle, which is easy to cause the fiber arrangement to deviate from the preset direction after fine carving, and finally leads to unqualified curvature of the prepared fiber bundle blank, uneven structure of the fiber bundle blank, and unqualified product.

[0003] SUMMARY Figure 2 The main purpose of the present application is to provide a hard fiber bundle blank and a preparation method thereof, and to solve the technical problem of providing a preparation method for a fiber bundle with a curved side surface or a non-central symmetric cross-section.

[0004] The main purpose of the present application is to provide a hard fiber bundle blank and a preparation method thereof, and to solve the technical problem of providing a preparation method for a fiber bundle with a curved side surface or a non-central symmetric cross-section.

[0005] ​The technical scheme of the present application is as follows: a kind of hard fiber bundle blank plate preparation method is provided, the hard fiber bundle blank plate includes fiber bundle;The fiber bundle is composed of several optical fibers;The optical fiber includes skin material;

[0006] The preparation method comprises:

[0007] 1) an etching layer and a cladding layer are arranged outside the fiber bundle to form a fusion pressure material;The etching layer is arranged between the fiber bundle and the cladding layer;The softening temperature and the thermal expansion coefficient of the skin material are higher than those of the cladding layer;

[0008] 2) the fusion pressure material is fused and cut to obtain a plate segment;The fusion pressure is first heated to 0-5 DEG C above the softening temperature of the cladding layer for 2-5 h, and then heated to 2-10 DEG C above the softening temperature of the skin material for 2-5 h;

[0009] 3) the plate segment is etched using an etching solution, then washed, dried, and a hard fiber bundle blank plate is obtained.

[0010] Preferably, the preparation method, wherein the difference between the softening temperature of the skin material and the softening temperature of the cladding layer is 50-120 DEG C, and the difference between the thermal expansion coefficients is 3*10 -7 K -1 ~ 15*10 -7 K -1 .

[0011] Preferably, the preparation method, wherein the etching layer is formed by arranging several borate glass rods in the shape of hexagonal prism or quadrangular prism;

[0012] The cladding layer is composed of an inner cladding layer and an outer cladding layer with the same material;The inner cladding layer is arranged adjacent to the etching layer;The thickness of the inner cladding layer is ≥5 mm;

[0013] The outer cladding layer is formed by arranging several glass rods in the shape of hexagonal prism or quadrangular prism;The thickness of the outer cladding layer is ≥3 mm.

[0014] Preferably, the preparation method, wherein the bottom surface of the borate glass rod forming the etching layer is in the shape of regular hexagon or square, and the length of the bottom surface of the regular hexagonal prism is 0.5-1 mm or the length of the bottom surface of the regular quadrangular prism is 0.5-1 mm;

[0015] The bottom surface of the glass rod forming the outer cladding layer is in the shape of regular hexagon or square, and the length of the bottom surface of the regular hexagonal prism is 0.5-3 mm or the length of the bottom surface of the regular quadrangular prism is 0.5-3 mm.

[0016] Preferably, the preparation method, wherein the step of setting the etching layer and the cladding layer outside the fiber bundle is as follows: first, setting the etching layer outside the fiber bundle, and then setting the cladding layer outside the etching layer.

[0017] Preferably, the preparation method, wherein the step of setting the etching layer and the cladding layer outside the fiber bundle is as follows: first, setting the etching layer outside the fiber bundle, and then setting the cladding layer outside the etching layer.

[0018] Preferably, the preparation method, wherein the ratio of the length of the etching layer in the plate segment to the thickness of the etching layer is less than 200:1.

[0019] Preferably, the preparation method, wherein in the step 3), the etching solution comprises: an acid etching solution and an alkali etching solution; the acid etching solution is an HCl solution with a concentration of 2-5wt% and / or an HNO3 solution with a concentration of 3.5-9wt%; the alkali etching solution is a NaOH solution with a concentration of 0.5-2wt%; and the etching step is an acid-alkali alternating etching.

[0020] Preferably, the preparation method, wherein the pressure of the melt pressing is 0.5-4MPa.

[0021] The object and the solution to the technical problem of the present application are also achieved by the following technical solution. According to the present application, a hard fiber bundle blank is prepared by the above-mentioned preparation method of the hard fiber bundle blank.

[0022] By the above-mentioned technical solution, the hard fiber bundle blank and the preparation method thereof proposed by the present application at least have the following advantages:

[0023] 1. The present application can realize the melt pressing of irregular fiber bundles, and the obtained fiber bundles have good curvature and can obtain the expected shape without deformation.

[0024] 2. The present application sets multiple etching layers and inner and outer cladding layers outside the fiber bundle, which can prevent the metal sliding block from thermal expansion and contraction during the melt pressing process, so as to prevent the deformation of the fiber bundle, the change of the curvature of the fiber bundle, and the deformation of the overall shape. In addition, the present application has certain requirements for the performance of the cladding layer material. The difference between the softening temperature of the leather and the softening temperature of the cladding layer is 50-120℃, and the difference between the thermal expansion coefficients is 3x10 -7 K -1 ~15x10 -7 K -1 of glass material, which is matched with the two heating processes in the melt pressing process to realize the melt pressing of irregularly shaped fiber bundles.

[0025] The above description is only a summary of the technical scheme of the present application. In order to make the technical means of the present application more clearly understood and implemented according to the content of the description, the preferred embodiments of the present application are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic view of a combination of a conventional hexagonal fiber bundle and a slider.

[0027] Figure 2 is a schematic view of the fiber arrangement of a trapezoidal fiber bundle deviating from the preset direction after fine carving.

[0028] Figure 3 is a schematic view of the melt-pressed material of Example 1.

[0029] Figure 4 is a schematic view of the melt-pressed material of Example 2. DETAILED DESCRIPTION

[0030] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined purposes, the specific embodiments, structures, features and effects of a hard fiber bundle blank and a preparation method thereof according to the present application are described in detail below with reference to the accompanying drawings and preferred embodiments. In the following description, different "an embodiment" or "embodiments" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0031] The present application provides a preparation method of a hard fiber bundle blank, as shown in FIG. Figures 3-4 The hard fiber bundle blank comprises a fiber bundle; the fiber bundle is composed of a plurality of optical fibers; the optical fibers comprise a sheath;

[0032] The preparation method comprises:

[0033] 1) An etching layer and a cladding layer are arranged outside the fiber bundle to form a melt-pressed material; the etching layer is arranged between the fiber bundle and the cladding layer; the softening temperature and the thermal expansion coefficient of the sheath are higher than those of the cladding layer;

[0034] 2) The melt-pressed material is melt-pressed and cut to obtain a plate segment; the melt-pressing is to heat the melt-pressed material to 0-5℃ above the softening temperature of the cladding layer for 2-5h, and then heat the melt-pressed material to 2-10℃ above the softening temperature of the sheath for 2-5h;

[0035] 3) The plate segment is etched using an etching solution, and then washed, dried to obtain a hard fiber bundle blank.

[0036] The fiber bundle is arranged in a certain shape according to the use environment, wherein the fiber is composed of a fiber core and a skin material, and the skin material is the skin material of the single fiber.

[0037] In the fusion pressing process, the fusion pressing material is first heated to 0-5 DEG C higher than the softening temperature of the cladding layer to soften the cladding layer, and then heated to 2-10 DEG C higher than the softening temperature of the skin material to soften the skin material. Since the softening temperature of the cladding layer is lower than that of the skin material, the cladding layer softens first during fusion pressing, which enables the cladding layer to support the fiber bundle inside the fusion pressing material and uniformly transmit mechanical pressure, achieving an effect similar to isostatic pressing.

[0038] Preferably, the preparation method, wherein the difference between the softening temperature of the skin material and the softening temperature of the cladding layer is 50-120 DEG C, and the difference between the thermal expansion coefficients is 3x10 -7 K -1 ~ 15x10 -7 K -1 .

[0039] The softening temperature of the cladding layer material is lower than that of the skin material. If the softening temperature of the cladding layer material is higher than that of the skin material, the skin material will soften, but the cladding layer will not soften, which will prevent the mechanical pressure from being transmitted, resulting in increased internal stress. However, if the softening point is too low, the viscosity will be too small, the support ability for the fiber bundle inside the fusion pressing material will be too small, and the fiber bundle will be easily scattered and deformed. The softening temperature of the cladding layer material used in the present application is 50-120 DEG C lower than that of the skin material, which can effectively prevent the above problems from occurring, and can enable the cladding layer to support the fiber bundle inside the fusion pressing material and uniformly transmit mechanical pressure, achieving fusion pressing of irregular fiber bundles.

[0040] Preferably, the preparation method, wherein the etching layer is formed by arranging a plurality of borate glass rods in the shape of a regular hexagonal prism or a regular quadrangular prism;

[0041] The cladding layer is composed of an inner cladding layer and an outer cladding layer made of the same material; the inner cladding layer is adjacent to the etching layer; the thickness of the inner cladding layer is greater than or equal to 5 mm;

[0042] The outer cladding layer is formed by arranging a plurality of glass rods in the shape of a regular hexagonal prism or a regular quadrangular prism; the thickness of the outer cladding layer is greater than or equal to 3 mm.

[0043] The etching layer used in the application is formed by arranging a plurality of borate glass rods in the shape of a regular hexagonal prism or a regular quadrangular prism, and the outer cladding layer is formed by arranging a plurality of glass rods in the shape of a regular hexagonal prism or a regular quadrangular prism. The glass rods in the shape of a regular hexagonal prism or a regular quadrangular prism can make the outer cladding layer and the etching layer more easily realize close stacking, and no pores appear. The specific shape is determined according to the fiber bundle to be fused and pressed.

[0044] The cladding layer of the application is divided into an inner cladding layer and an outer cladding layer. The inner cladding layer can be a plurality of glass blocks, which can make the inner cladding layer simple in structure and convenient to operate, and can provide sufficient support. Secondly, the thickness of the inner cladding layer needs to be greater than or equal to 5mm. The main function of the inner cladding layer is to homogenize stress. If the inner cladding layer is too thin or too thick, the stress cannot be homogenized, which will cause the fiber bundle to deform after being fused and pressed. However, in the subsequent fusion pressing, the sliding block will form a force in the sliding direction when it slides on the inner fused and pressed material. If the outer cladding layer is not set, the sliding block will directly contact the inner cladding layer, i.e. the glass block, which will be easily broken due to the large stress inside the glass block. After setting the outer cladding layer, since the outer cladding layer is composed of a plurality of glass rods, it can slide with the sliding block, and the stress is small, which can prevent the inner cladding layer from breaking.

[0045] Preferably, the preparation method described above, wherein the bottom surface shape of the borate glass rods constituting the etching layer is a regular hexagon or a square, the bottom surface side length of the regular hexagonal prism is 0.5-1mm or the bottom surface side length of the regular quadrangular prism is 0.5-1mm.

[0046] The bottom surface shape of the glass rods constituting the outer cladding layer is a regular hexagon or a square, the bottom surface side length of the regular hexagonal prism is 0.5-3mm or the bottom surface side length of the regular quadrangular prism is 0.5-3mm.

[0047] The etching layer of the application is made of borate glass. Borate glass is used because it can be removed by acid-base etching. After removing the etching layer, the cladding layer will also fall off accordingly, and finally the fiber bundle after fusion pressing is obtained.

[0048] The etching layer is composed of a plurality of borate glass rods, and the outer cladding layer is composed of a plurality of glass rods; the bottom surface of the glass rod is a regular hexagon or a square; the glass rod with a regular hexagon or a square bottom edge is easier to be tightly packed, thereby improving the supporting capacity of the etching layer and the outer cladding layer; in addition, the size of the cross section of the borate glass rod also needs to be considered; when the cross section is too large, the thermal compatibility of the etching layer and the fiber bundle needs to be further considered; if the thermal compatibility is not matched, the risk of explosion is high; if the cross section is too small, although the thermal mismatch does not cause excessive stress, the glass rod arrangement operation is difficult, and the working efficiency is reduced; however, the regular hexagonal prism or the regular quadrangular prism with a bottom edge length of 0.5-1 mm is used in the present application, so that the thermal compatibility of the etching layer and the fiber bundle is good, the risk of explosion is avoided, and the etching layer is also easy to be tightly packed, thereby improving the supporting capacity of the etching layer.

[0049] Preferably, the preparation method, wherein the step of arranging the etching layer and the cladding layer outside the fiber bundle is as follows: first, arranging the etching layer outside the fiber bundle, and then arranging the cladding layer outside the etching layer.

[0050] The cladding method is as follows: first, surrounding one or more layers of borate glass rods around the side of the arranged fiber bundle to form an etching layer; then, cladding an inner cladding layer outside the etching layer to form a blank section with a hexagonal prism or quadrangular prism shape; and finally, cladding a plurality of glass rods outside the inner cladding layer to form an outer cladding, thereby obtaining a fused pressure material.

[0051] Preferably, the preparation method, wherein the step of arranging the etching layer and the cladding layer outside the fiber bundle is as follows: first, arranging the cladding layer, then arranging the etching layer above the cladding layer, then arranging the fiber bundle above the etching layer, then arranging the etching layer above the fiber bundle, and finally arranging the cladding layer above the etching layer.

[0052] The method is as follows: first, arranging the outer cladding layer fiber layer by layer, then arranging the inner cladding glass block, then arranging the etching layer fiber and the fiber bundle in sequence inside the inner cladding, and finally obtaining a fused pressure material.

[0053] Preferably, the preparation method, wherein the ratio of the length of the etching layer to the thickness of the etching layer in the blank section is less than 200:1.

[0054] Preferably, the preparation method, wherein in step 3), the etching liquid comprises an acid etching liquid and an alkali etching liquid; the acid etching liquid is an HCl solution with a concentration of 2-5 wt% and / or an HNO3 solution with a concentration of 3.5-9 wt%; the alkali etching liquid is an NaOH solution with a concentration of 0.5-2 wt%; and the etching step is an acid-alkali alternating etching.

[0055] The acid-base alternate etching method is used to remove the etching layer, the acid etching solution is used to dissolve and remove the etching layer, the base etching solution is used to clean the fiber bundle and remove the reaction product attached to the surface, then the acid-base alternate etching method, preferably the acid-base-acid alternate etching method, is used to dissolve the etching layer, so that the fiber bundle is separated out. After the etching is completed, the fiber bundle is cleaned by using deionized water to remove the residual etching solution, then the fiber bundle is placed in isopropyl alcohol for ultrasonic cleaning, so that the dehydration effect is better, and then the fiber bundle is placed in an oven for drying, so that the hard fiber bundle blank plate is obtained.

[0056] The acid etching solution is selected from the group consisting of an HCl solution with a concentration of 2-5 wt% and / or an HNO3 solution with a concentration of 3.5-9 wt%. If the concentration of the dilute HCl solution is less than 2 wt% or the concentration of the dilute HNO3 solution is less than 3.5 wt%, the acid etching efficiency is too low. If the concentration of the dilute HCl solution is more than 5 wt% or the concentration of the dilute HNO3 solution is more than 9 wt%, the fiber bundle is also corroded seriously. The base etching solution is selected from an NaOH solution with a concentration of 0.5-2 wt%. If the concentration is less than 0.5 wt%, the reaction product cannot be completely removed. If the concentration is more than 2 wt%, the fiber bundle is also corroded seriously.

[0057] Preferably, the preparation method of the hard fiber bundle blank plate, wherein the pressure of the melt pressing is 0.5-4 MPa.

[0058] The application further provides a hard fiber bundle blank plate prepared by the preparation method of the hard fiber bundle blank plate.

[0059] The application will be further described in conjunction with specific examples. However, it should not be understood as a limitation to the scope of protection of the application. Some non-essential improvements and adjustments made by the person skilled in the art based on the content of the application still belong to the scope of protection of the application.

[0060] Unless otherwise specified, the materials and reagents involved below are commercially available and well known to the person skilled in the art. Unless otherwise specified, the methods are well known in the art. Unless otherwise defined, the technical terms or scientific terms used should be understood as the common meaning by the person skilled in the art.

[0061] Example 1

[0062] A preparation method of a hard fiber bundle blank plate, as shown in Figure 3 The method comprises the following steps:

[0063] Preparation of raw materials:

[0064] The fiber bundle is a cylindrical fiber bundle with a diameter of 40 mm and has been arranged. The fiber bundle skin softening point is 620℃, and the thermal expansion coefficient is 86×10 -7 K -1.

[0065] A glass with a softening point of 500°C and a thermal expansion coefficient of 83x10 -7 K -1 is drawn into a four-prism glass rod, the cross section of the glass rod is a regular hexagon with a side length of 0.5mm, which is used to form the outer cladding layer, and the thickness of the outer cladding layer is 5mm; at the same time, a glass block is processed from the same glass material, the cross section of the glass block is a regular hexagon with a side length of 53mm on the outside and a circle with a diameter of 42.5mm on the inside, which is used to form the inner cladding layer, and the thinnest part of the inner cladding layer is 5.25mm.

[0066] A borate glass rod with a square cross section with a side length of 1mm is drawn to form the etching layer.

[0067] Preparation of the hard fiber bundle blank:

[0068] 1) First, surround the fiber bundle 7 with a layer of borate glass rod on the outside to form the etching layer 6;

[0069] 2) Then load the glass block to form the inner cladding layer 5, so that the whole forms a blank section with a hexagonal prism shape, and then coat 10 layers of glass rods on the side to form the outer cladding layer 4, obtaining the fusion-pressed material;

[0070] 3) Use the sliding block 3 to coat the fusion-pressed material, put it into a conventional mechanical fusion-pressing mold, and place it in a fusion-pressing furnace, first heat to 502°C, keep for 5h, then heat to 623°C and keep for 3h, apply a mechanical pressure of 2MPa on the fusion-pressing mold, and after fusion pressing, cut it into a plate section with a thickness of 10mm, the length of the etching layer to the thickness of the etching layer ratio is 10:1;

[0071] 4) Use 2wt% HCl as the acid etching solution and 0.5wt% NaOH solution as the alkali etching solution, and treat the plate section by alternating acid-alkali-acid etching, after etching, clean the residual etching solution of the fiber bundle with deionized water, then put it into isopropyl alcohol for ultrasonic cleaning, and finally place it in an oven for drying, obtaining the hard fiber bundle blank.

[0072] Example 2

[0073] A method for preparing a hard fiber bundle blank, as shown in Figure 4 , the method comprises:

[0074] Preparation of raw materials:

[0075] The fiber bundle is a fiber bundle with a cross section in the shape of an isosceles trapezoid, the four sides of the trapezoid are 20mm, 20mm, 20mm, and 32mm respectively, the softening point of the fiber bundle skin is 608°C, and the thermal expansion coefficient is 81x10 -7 K -1 .

[0076] A glass with a softening point of 520°C and a thermal expansion coefficient of 66 x 10 -7 K -1 is drawn into a four-prism glass rod with a square cross-section of 3 mm in length of the side, which is used to form the outer cladding layer; at the same time, the same kind of glass material is processed into four glass blocks, and the cross-section of the assembled glass blocks is a square of 48 mm in length of the side outside and an isosceles trapezoid inside, which is used to form the inner cladding layer, and the thinnest part of the inner cladding layer is 8 mm in thickness.

[0077] A borate glass rod with a square cross-section of 0.5 mm in length of the side is drawn, which is used to form the etching layer, and the thickness of the etching layer is 0.5 mm.

[0078] Preparation of the hard fiber bundle blank plate:

[0079] 1) A conventional four-prism plate arranging die is used, and the glass rods are stacked layer by layer until the thickness of the outer cladding layer 9 is 9 mm;

[0080] 2) Then the glass blocks are placed on the inner side of the outer cladding layer to form the inner cladding layer 10, and the borate glass rods are placed on the inner side of the inner cladding layer to form the etching layer 11, and finally the fiber bundle 12 is placed to obtain the fusion-pressed material;

[0081] 3) The fusion-pressed material is covered with a sliding block 8 and placed into a conventional mechanical fusion-pressing die, which is placed in a fusion-pressing furnace, and first heated to 525°C of the cladding layer material for 2 h, and then heated to 613°C for 5 h, and a mechanical pressure of 1.5 MPa is applied on the fusion-pressing die, and after fusion pressing, the plate segment with a thickness of 2 mm, a length of the etching layer and a thickness of the etching layer ratio of 40:1 is cut;

[0082] 4) The plate segment is treated by acid-alkali-acid alternating etching using 3.7wt% HCl as the acid etching solution and 1wt% NaOH solution as the alkali etching solution, after etching, the residual etching solution of the fiber bundle is cleaned with deionized water, then it is placed in isopropanol for ultrasonic cleaning, and finally it is placed in an oven for drying to obtain the hard fiber bundle blank plate.

[0083] Example 3

[0084] A method for preparing a hard fiber bundle blank plate, the method comprising:

[0085] Preparation of raw materials:

[0086] The fiber bundle is a cylindrical fiber bundle with a diameter of 40 mm which has been arranged, and the fiber bundle skin has a softening point of 620°C and a thermal expansion coefficient of 86 x 10 -7 K -1 .

[0087] A glass with a softening point of 500°C and a thermal expansion coefficient of 83x10 -7 K -1 was drawn into a four-prism glass rod with a cross-section of a regular hexagon with a side length of 2 mm, which was used to form the outer cladding layer. Meanwhile, a glass block with a cross-section of a regular hexagon with a side length of 54 mm on the outside and a circle with a diameter of 42 mm on the inside was processed from the same glass material, which was used to form the inner cladding layer. The thickness of the inner cladding layer was 6 mm at the thinnest point.

[0088] A borate glass rod with a cross-section of a square with a side length of 0.8 mm was drawn, which was used to form the etching layer.

[0089] Preparation of the hard fiber bundle blank:

[0090] 1) First, a layer of borate glass rod was wrapped around the outside of the fiber bundle;

[0091] 2) Then, the glass block was loaded to form a blank section with a hexagonal prism shape, and 10 layers of glass rod were wrapped around the side surface to obtain a fusion-pressed material;

[0092] 3) The fusion-pressed material was wrapped with a sliding block and placed into a conventional mechanical fusion-pressing mold in a fusion-pressing furnace. The temperature was first raised to 502°C and held for 5 h, and then raised to the fiber bundle skin softening point of 623°C and held for 3 h. A mechanical pressure of 2 MPa was applied to the fusion-pressing mold. After fusion pressing, the blank section was cut to a thickness of 10 mm, and the length to thickness ratio of the etching layer was 12.5:1.

[0093] 4) The blank section was treated by acid-alkali-acid alternating etching using 5wt% HNO3 as the acid etching solution and 2wt% NaOH solution as the alkali etching solution. After etching, the residual etching solution on the fiber bundle was cleaned with deionized water, and then the fiber bundle was placed in isopropyl alcohol for ultrasonic cleaning. Finally, the fiber bundle was placed in an oven for drying to obtain the hard fiber bundle blank.

[0094] Comparative Example 1

[0095] A cylindrical fiber bundle with a diameter of 40 mm was fusion-pressed by a conventional fusion-pressing method. After fusion pressing, the hard fiber bundle blank was cut to a thickness of 10 mm.

[0096] Comparative Example 2

[0097] A fiber bundle with a cross-section of an isosceles trapezoid with four sides of 20 mm, 20 mm, 20 mm, and 32 mm was fusion-pressed by a conventional fusion-pressing method. After fusion pressing, the hard fiber bundle blank was cut to a thickness of 2 mm.

[0098] The shapes of the hard fiber bundle blanks obtained in Examples 1-3 and Comparative Examples 1-2 were compared, and the results are shown in the following table:

[0099] Table 1

[0100] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Curvature of the surface Pass ---- Pass Fail ---- Deformation No deformation No deformation No deformation Deformation Deformation

[0101] In the above embodiments, the description of each embodiment is focused on, and the part not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0102] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any person skilled in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent change and modification of the above embodiments according to the technical essence of the present application are still within the scope of the technical solution of the present application.

Claims

1. A method for preparing a rigid fiber bundle blank, characterized in that, The rigid fiber bundle blank includes fiber bundles; the fiber bundles are composed of a plurality of optical fibers; the optical fibers include leather material; The preparation method includes: 1) An etching layer and a cladding layer are formed on the outside of the fiber bundle to create a fused material; the etching layer is disposed between the fiber bundle and the cladding layer; the softening temperature and coefficient of thermal expansion of the cladding material are higher than those of the cladding layer; the etching layer is formed by arranging several borate glass rods in the shape of regular hexagonal prisms or regular square prisms; the cladding layer consists of an inner cladding layer and an outer cladding layer of the same material; the inner cladding layer is disposed adjacent to the etching layer; the thickness of the inner cladding layer is ≥5mm; the outer cladding layer is formed by arranging several glass rods in the shape of regular hexagonal prisms or regular square prisms; the thickness of the outer cladding layer is ≥3mm. 2) The molten material is molten and pressed, and then cut to obtain plate segments; the molten pressing is performed by first heating the molten material to 0-5°C above the softening temperature of the coating layer and holding it at that temperature for 2-5 hours, and then heating the molten material to 2-10°C above the softening temperature of the leather and holding it at that temperature for 2-5 hours. 3) The plate segment is etched using an etching solution, then cleaned and dried to obtain a rigid fiber bundle blank.

2. The preparation method according to claim 1, characterized in that, The difference between the softening temperature of the leather and the softening temperature of the covering layer is 50–120°C, and the difference in their coefficients of thermal expansion is 3 × 10⁻⁶. -7 K -1 ~15×10 -7 K -1 .

3. The preparation method according to claim 1, characterized in that, The bottom surface of the borate glass rod that makes up the etching layer is hexagonal or square, and the side length of the bottom surface of the regular hexagonal prism is 0.5 to 1 mm or the side length of the bottom surface of the regular square prism is 0.5 to 1 mm. The glass rod that makes up the outer coating layer has a base shape that is either a regular hexagon or a square. The base side length of the regular hexagonal prism is 0.5 to 3 mm, or the base side length of the regular square prism is 0.5 to 3 mm.

4. The preparation method according to claim 1, characterized in that, The steps for setting an etching layer and a coating layer on the outside of the fiber bundle are as follows: first, an etching layer is set on the outside of the fiber bundle, and then a coating layer is set on the outside of the etching layer.

5. The preparation method according to claim 1, characterized in that, The steps for setting the etching layer and the coating layer on the outside of the fiber bundle are as follows: first, the coating layer is deposited, then the etching layer is placed on top of the coating layer, then the fiber bundle is placed on top of the etching layer, then the etching layer is placed on top of the fiber bundle, and finally the coating layer is placed on top of the etching layer.

6. The preparation method according to claim 1, characterized in that, The ratio of the length of the etched layer to the thickness of the etched layer in the plate segment is less than 200:

1.

7. The preparation method according to claim 1, characterized in that, The etching solution includes an acid etching solution and an alkaline etching solution; the acid etching solution is an HCl solution with a concentration of 2-5 wt% and / or an HNO3 solution with a concentration of 3.5-9 wt%; the alkaline etching solution is a NaOH solution with a concentration of 0.5-2 wt%; the etching is an alternating acid-alkaline etching process.

8. The preparation method according to claim 1, characterized in that, The pressure of the melting and pressing is 0.5 to 4 MPa.

9. A rigid fiber bundle blank, characterized in that, It is prepared by the method for preparing hard fiber bundle blanks according to any one of claims 1 to 8.

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