Illumination optical fiber and preparation method and application thereof

Abstract

The invention provides an illumination optical fiber and a preparation method and application thereof. The illumination optical fiber includes a core derived from a first multi-component glass and a cladding derived from a second multi-component glass; moreover, the first multi-component glass comprises the following components in mole percent: 38-42% of SiO2; zrO2: 4 to 6 percent; 7 to 12 percent of B2O3; 8 to 10 percent of La2O3; 29% to 35% of BaO; 5 to 8 percent of ZnO; 1 to 2.5 percent of Na2O; the second multi-component glass is prepared from the following components in percentage by mole: 30 to 45 percent of SiO2; the content of B2O3 is 40 to 60 percent; 2 to 6 percent of Al2O3; 0 to 3 percent of BaO; 0 to 2 percent of ZnO; 0 to 2 percent of K2O; and 2 to 4 percent of Na2O. The illumination optical fiber is not easy to break when being repeatedly bent or twisted, and has the advantages of high light transmission efficiency, bending resistance and long service life.

Description

Technical Field

[0001] This invention relates to an optical fiber for lighting, its preparation method and applications, and belongs to the field of optical glass applications. Background Technology

[0002] Endoscopes, as minimally invasive surgical instruments, are widely used in medical diagnosis and treatment. Traditional endoscope illumination systems typically use fiber optic bundles for illumination, but existing fibers are prone to breakage when repeatedly bent or twisted, leading to decreased light transmission efficiency or even failure, thus affecting the lifespan of the endoscope.

[0003] To improve the lifespan of endoscopes, the composition of the fiber core glass and cladding glass is adjusted to optimize the matching between the core material and the cladding glass, thereby increasing the fiber's lifespan.

[0004] Chinese patent application CN108139536A discloses an image transmission optical fiber, but its fiber core glass contains Ta2O5, resulting in high raw material costs and poor environmental friendliness. Using the same melting process, the glass containing Ta2O5 has relatively lower transmittance, leading to increased fiber loss. Simultaneously, its core occupancy is low, with a maximum of only 48% in the embodiments, resulting in low optical transmission efficiency.

[0005] Chinese patent application CN119330580A discloses a method for fabricating low-loss, high numerical aperture, and high core-to-cladding ratio glass optical fibers. The fiber has a low numerical aperture and low fiber drawing efficiency, making it prone to breakage. In Example 3, the fiber still broke even when the tension was reduced to 8-10g, indicating low tensile strength of the glass.

[0006] However, high numerical aperture optical fibers have a large refractive index difference between the core glass and the cladding glass, resulting in significant differences in their composition and content. This may lead to matching problems, and the optical fiber is prone to breakage when repeatedly bent or twisted, resulting in decreased optical transmission efficiency or even failure, which affects the service life of the endoscope.

[0007] Therefore, developing a multi-component glass lighting optical fiber has become an urgent technical problem to be solved. Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In view of the technical problems existing in the prior art, such as the large refractive index difference between the core glass and the cladding glass in high numerical aperture optical fibers, which leads to significant differences in their composition and content, and therefore may cause matching problems, and the optical fiber is prone to breakage when repeatedly bent or twisted, resulting in a decrease in optical transmission efficiency or even failure, the present invention first provides a bend-resistant and long-life lighting optical fiber.

[0010] The present invention also provides a method for preparing lighting optical fibers, which is simple and easy to implement, uses readily available raw materials, and is suitable for mass production.

[0011] Solution for solving the problem

[0012] This invention provides an illumination optical fiber, wherein the illumination optical fiber comprises a core and a cladding, wherein...

[0013] The fiber core is derived from a first multi-component glass, and the cladding is derived from a second multi-component glass; and...

[0014] The first multi-component glass comprises the following components in molar percentage:

[0015] SiO2: 38-42%, preferably 39-41%;

[0016] ZrO2: 4-6%, preferably 4.5-5.5%;

[0017] B2O3: 7-12%, preferably 8-11%;

[0018] La2O3: 8-10%, preferably 8.5-9.5%;

[0019] BaO: 29-35%, preferably 30-33%;

[0020] ZnO: 5-8%, preferably 6-7.5%;

[0021] Na2O: 1-2.5%, preferably 1.5-2%;

[0022] The second multicomponent glass comprises the following components in molar percentage:

[0023] SiO2: 30-45%, preferably 33-40%;

[0024] B2O3: 40-60%, preferably 42-58%;

[0025] Al2O3: 2-6%, preferably 3-5%;

[0026] BaO: 0-3%, preferably 1-2%;

[0027] ZnO: 0-2%, preferably 0.1-1%;

[0028] K2O: 0-2%, preferably 0.1-1%

[0029] Na₂O: 2–4%, preferably 2.5–3.5%.

[0030] According to the illumination optical fiber of the present invention, the numerical aperture NA of the illumination optical fiber is greater than 0.8;

[0031] The difference in the linear thermal expansion coefficient Δα of the illumination optical fiber is 16 × 10⁻⁶. -7 / ℃~50×10 -7 / ℃, the difference in linear thermal expansion coefficient Δα is the value obtained by subtracting the linear thermal expansion coefficient α2 of the second multi-component glass from the linear thermal expansion coefficient α1 of the first multi-component glass at 100~300℃.

[0032] In the cross-section of the lighting optical fiber, the core occupancy rate is greater than 70%, wherein the core occupancy rate is the ratio of the area occupied by the core to the area occupied by the lighting optical fiber.

[0033] The diameter of the single filament of the illumination optical fiber is less than 55 μm.

[0034] According to the lighting optical fiber of the present invention, in the first multi-component glass, the sum of SiO2 and B2O3 (∑SiO2+B2O3) is 46-50% by molar percentage.

[0035] According to the lighting optical fiber of the present invention, the refractive index nd1 of the first multi-component glass is 1.72 or higher.

[0036] The glass transition temperature Tg1 of the first multi-component glass is above 650℃;

[0037] The linear thermal expansion coefficient α1 of the first multi-component glass at 100–300 °C is 96 × 10⁻⁶. -7 / ℃ or above; the acid resistance stability D of the first multi-component glass A Water resistance stability D is rated as level 3 or above. W Level 1;

[0038] The density of the first multi-component glass is no more than 4.68 g / cm³. 3 .

[0039] According to the illumination optical fiber of the present invention, in the second multi-component glass, the sum of SiO2+B2O3 (∑SiO2+B2O3) is 83-91% by molar percentage.

[0040] According to the lighting optical fiber of the present invention, the refractive index nd2 of the second multi-component glass is 1.52 or less;

[0041] The glass transition temperature Tg2 of the second multi-component glass is below 580℃;

[0042] The linear thermal expansion coefficient α2 of the second multi-component glass at 100–300 °C is 80 × 10⁻⁶. -7 / ℃ below.

[0043] According to the lighting optical fiber of the present invention, the acid resistance D of the second multi-component glass is... A Grade 1, water resistance stability D W Level 1 or Level 2;

[0044] The density of the second multi-component glass is not more than 2.5 g / cm³. 3 .

[0045] The present invention also provides a method for preparing an illumination optical fiber according to the present invention, which includes the following steps:

[0046] The raw materials for the first multi-component glass are mixed and made into a core glass rod.

[0047] The raw materials for the second multi-component glass are mixed and made into cladding glass tubes.

[0048] The core glass rod and the cladding glass tube are nested together, placed in a drawing tower heating furnace, vacuumed and heated, and then drawn to obtain an illumination optical fiber.

[0049] According to the preparation method of the present invention, the preparation method of the core glass rod or cladding glass tube includes weighing each component in proportion, mixing them evenly, melting them, and then pouring them into a molding mold for the core glass rod or the molding mold for the cladding glass tube to obtain the core glass rod or the cladding glass tube.

[0050] The present invention also provides the use of the illumination optical fiber according to the present invention in an endoscope.

[0051] The effects of the invention

[0052] The optical fiber of this invention is not easily broken when repeatedly bent or twisted, has high light transmission efficiency, and has the properties of bend resistance and long service life.

[0053] The method for preparing the lighting optical fiber of the present invention is simple and easy to implement, the raw materials are readily available, and it is suitable for mass production. Attached Figure Description

[0054] Figure 1 A schematic cross-sectional view of the monofilament fiber in the illumination fiber of the present invention is shown. Detailed Implementation

[0055] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0056] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0057] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0058] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0059] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0060] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0061] In this specification, "not containing" and "0%" mean that the compound, element or other substance was not intentionally added to the glass of this invention as a raw material. However, as raw materials and / or equipment for producing glass, there may be some impurities or components that are not intentionally added, which are present in small or trace amounts in the final glass. Such cases are also within the scope of protection of this patent.

[0062] <First Aspect>

[0063] like Figure 1 As shown, a first aspect of the present invention provides an illumination optical fiber, the illumination optical fiber comprising a core and a cladding, wherein,

[0064] The fiber core is derived from a first multi-component glass, and the cladding is derived from a second multi-component glass; and...

[0065] The first multicomponent glass comprises the following components in molar percentage:

[0066] SiO2: 38-42%, preferably 39-41%;

[0067] ZrO2: 4-6%, preferably 4.5-5.5%;

[0068] B2O3: 7-12%, preferably 8-11%;

[0069] La2O3: 8-10%, preferably 8.5-9.5%;

[0070] BaO: 29-35%, preferably 30-33%;

[0071] ZnO: 5-8%, preferably 6-7.5%;

[0072] Na2O: 1-2.5%, preferably 1.5-2%;

[0073] The second multicomponent glass comprises the following components in molar percentage:

[0074] SiO2: 30-45%, preferably 33-40%;

[0075] B2O3: 40-60%, preferably 42-58%;

[0076] Al2O3: 2-6%, preferably 3-5%;

[0077] BaO: 0-3%, preferably 1-2%;

[0078] ZnO: 0-2%, preferably 0.1-1%;

[0079] K2O: 0-2%, preferably 0.1-1%

[0080] Na₂O: 2–4%, preferably 2.5–3.5%.

[0081] The fiber core of this invention has a occupancy rate of over 70%, resulting in high light transmission efficiency. Furthermore, the raw materials are inexpensive and do not contain precious metals such as Ta. The glass exhibits good mechanical properties and a low breakage rate during drawing. This significantly improves the matching compatibility and lifespan of endoscopic illumination, thereby meeting the needs of medical diagnosis and treatment.

[0082] In this invention, the numerical aperture (NA) of the lighting optical fiber is greater than 0.8. A larger numerical aperture (NA) allows for a larger illumination area and improves overall lighting efficiency. Furthermore, it reduces leakage during bending, making it suitable for scenarios requiring frequent bending or complex wiring. Therefore, the numerical aperture (NA) of the lighting optical fiber in this invention is greater than 0.8.

[0083] In this invention, regarding the numerical aperture of the optical fiber, the refractive index of the core glass is nd1, the refractive index of the cladding glass is nd2, and the numerical aperture NA of optical fiber 1 is calculated using the following formula:

[0084]

[0085] The refractive index nd1 of the core glass and the refractive index nd2 of the cladding glass are values ​​obtained by measurement using the national standard GB / T7962.1-2010.

[0086] Furthermore, the difference in the linear thermal expansion coefficient Δα of the illumination optical fiber is 16 × 10⁻⁶. -7 / ℃~50×10 -7 / ℃. Wherein, the difference in linear thermal expansion coefficients Δα is the value obtained by subtracting the linear thermal expansion coefficient α2 of the second multi-component glass at 100–300℃ from the linear thermal expansion coefficient α1 of the first multi-component glass at 100–300℃. When the difference in linear thermal expansion coefficients Δα of the illumination optical fiber is 16 × 10⁻⁶... -7 / ℃~50×10 -7 At a temperature of / ℃, the required optical transmission efficiency can be achieved while reducing costs.

[0087] Furthermore, in the cross-section of the illumination optical fiber, the core occupancy rate is greater than 70%, where the core occupancy rate is the ratio of the area occupied by the core to the area occupied by the illumination optical fiber. In this invention, the larger the core area, the higher the transmittable optical power. Additionally, coupling is simplified; a larger core provides greater alignment tolerance with the light source and is more suitable for coupling with LEDs. Therefore, in this invention, the core occupancy rate is greater than 70%.

[0088] Furthermore, in this invention, the diameter of the single filament of the illumination optical fiber is less than 55 μm. It should be noted that the single filament of the illumination optical fiber of this invention is obtained through fiber drawing, therefore it has a certain degree of error, generally less than 10% in diameter.

[0089] First multi-component glass

[0090] In this invention, the fiber core is derived from a first multi-component glass, wherein the first multi-component glass comprises the following components in molar percentage:

[0091] SiO2: 38-42%, preferably 39-41%;

[0092] ZrO2: 4-6%, preferably 4.5-5.5%;

[0093] B2O3: 7-12%, preferably 8-11%;

[0094] La2O3: 8-10%, preferably 8.5-9.5%;

[0095] BaO: 29-35%, preferably 30-33%;

[0096] ZnO: 5-8%, preferably 6-7.5%;

[0097] Na₂O: 1–2.5%, preferably 1.5–2%.

[0098] SiO2 acts as a network forging, forming the skeletal structure of the glass, primarily existing in the form of silicon-oxygen tetrahedra. If the SiO2 content is less than 38%, the base glass will exhibit poor thermal and chemical stability, as well as low mechanical strength. If the SiO2 content is higher than 42%, the glass melting process will involve high temperatures, making it difficult to eliminate bubbles in the glass, and the refractive index will decrease significantly, preventing the core glass from reaching the target refractive index. Therefore, the SiO2 content in this invention, by molar percentage, is 38-42%, for example: 38%, 39%, 40%, 41%, 42%, etc.

[0099] B2O3 is a network forgery in glass, which can improve the melting performance and chemical stability of glass. When the B2O3 content is less than 7%, the melting performance and thermal stability of the glass deteriorate; when the B2O3 content is higher than 12%, the refractive index decreases, and it is difficult to obtain fiber-core glass with a glass transition temperature (Tg1) of 650°C or higher. Therefore, the B2O3 content should be controlled at around 7-12%, preferably 8-11%. Therefore, in this invention, the B2O3 content is 7-12% in molar percentage, for example: 7%, 8%, 9%, 10%, 11%, 12%, etc.

[0100] In the first multicomponent glass, the sum of SiO2 and B2O3 (∑SiO2+B2O3) is 46-50% by molar percentage. When ∑SiO2+B2O3 is 46-50%, the first multicomponent glass with the desired refractive index can be obtained.

[0101] In the glass system of this invention, ZrO2 is an intermediate oxide. ZrO2 can improve the refractive index and chemical stability of the glass. However, when its content is less than 4%, the effect of improving the refractive index is not obvious, while when its content is greater than 6%, it is difficult to melt the glass and foreign matter will be generated, increasing the difficulty of melting. Therefore, the content of ZrO2 should be controlled between 4% and 6%, such as 4.5%, 5%, 5.5%, etc.

[0102] In the glass system of this invention, La2O3 acts as a network exogenous substance. La2O3 can form stable compounds with other elements in the glass, thereby preventing oxidation or reduction and improving the chemical stability of the glass. Its most important role in the core glass is to increase the glass's refractive index. When the La2O3 content is less than 8%, it is difficult to achieve a high refractive index; when the La2O3 content is higher than 10%, it may exceed the maximum solubility of this element in the glass system, leading to glass crystallization. Therefore, in this invention, the La2O3 content is 8-10% by molar percentage, for example, 8%, 8.5%, 9%, 9.5%, 10%, etc.

[0103] In the glass system of this invention, BaO serves as the network outer layer, improving the refractive index and acting as a flux. Simultaneously, the addition of BaO significantly enhances the refractive index of the optical fiber while preventing redshift at the ultraviolet absorption edge, making it an ideal choice for short-distance optical transmission systems. However, when the BaO content is less than 29%, it is difficult to achieve a refractive index (nd) above 1.72, while a BaO content higher than 35% will cause the core glass to crystallize too quickly, leading to easy crystallization. Therefore, the BaO content, in molar percentage, should be controlled between 29% and 35%, for example: 29%, 30%, 31%, 32%, 33%, 34%, 35%, etc.

[0104] In the glass system of this invention, ZnO acts as a network expanse. A small amount of ZnO can improve the crystallization properties of the glass, especially by reducing the relaxation temperature. The more ZnO introduced, the more significant the reduction in the relaxation temperature. When the ZnO content is less than 5%, the glass has a low refractive index; when the ZnO content is higher than 8%, the glass is prone to crystallization. Therefore, the ZnO content, in molar percentage, should be controlled between 5% and 8%, for example, 5%, 6%, 7%, 8%, etc.

[0105] Na₂O is an external network component in the glass system of this invention. Na₂O provides free oxygen at high temperatures. 2- This causes the [SiO4] tetrahedral structural units to lose their balance, thus lowering the glass melting temperature and sag temperature. When the Na2O content is less than 1%, the reduction in glass transition temperature is not significant and difficult to achieve the desired effect. Na2O has low solubility in this glass system, and when the Na2O content is higher than 2.5%, crystallization will occur. Therefore, the Na2O content is controlled at 1-2.5% by molar percentage, for example: 1%, 1.5%, 2%, 2.5%, etc.

[0106] In this invention, the refractive index nd1 of the first multi-component glass is greater than 1.72; the glass transition temperature Tg1 of the first multi-component glass is above 650℃; and the coefficient of linear thermal expansion α1 of the first multi-component glass at 100~300℃ is 96×10⁻⁶. -7 / ℃ or above.

[0107] Furthermore, the acid resistance stability D of the first multi-component glass A Water resistance stability D is rated as level 3 or above. W It is classified as Grade 1; the density of the first multi-component glass is no more than 4.68 g / cm³. 3 .

[0108] Second multi-component glass

[0109] In this invention, the cladding layer is derived from a second multi-component glass; the second multi-component glass comprises the following components in molar percentage:

[0110] SiO2: 30-45%, preferably 33-40%;

[0111] B2O3: 40-60%, preferably 42-58%;

[0112] Al2O3: 2-6%, preferably 3-5%;

[0113] BaO: 0-3%, preferably 1-2%;

[0114] ZnO: 0-2%, preferably 0.1-1%;

[0115] K2O: 0-2%, preferably 0.1-1%

[0116] Na2O: 2-4%, preferably 2.5-3.5%;

[0117] SiO2 acts as a network forging, forming the skeletal structure of the glass, primarily existing in the form of silicon-oxygen tetrahedra. If the SiO2 content is less than 30%, the base glass will exhibit poor thermal and chemical stability, as well as low mechanical strength. If the SiO2 content exceeds 45%, the glass melting process will involve high temperatures, making it difficult to eliminate bubbles in the glass, and the refractive index will decrease significantly, preventing the core glass from reaching the target refractive index. Therefore, in this invention, the SiO2 content, by molar percentage, is 30–45%, for example: 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 43%, etc.

[0118] B2O3 is a network forgery in glass, which can improve the melting performance and chemical stability of glass. When the B2O3 content is less than 40%, the refractive index of the glass will increase, making it difficult to meet the refractive index difference between the core layer and the cladding glass. When the B2O3 content is higher than 60%, the amount of SiO2 introduced will decrease accordingly, which may reduce the mechanical strength of the glass. Therefore, in this invention, the B2O3 content is 40-60% by molar percentage, preferably 42-58%, for example: 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, etc.

[0119] In the second multicomponent glass, the sum of SiO2 + B2O3 (∑SiO2 + B2O3) is 83–91% by molar percentage. When ∑SiO2 + B2O3 is 83–91%, the desired refractive index can be obtained.

[0120] Al₂O₃ acts as a network intermediate in glass. It connects with the glass framework, making the glass structure more compact and improving its chemical, mechanical, and thermal stability. When the Al₂O₃ content is less than 2%, its contribution to glass stability is insufficient. However, when the Al₂O₃ content is higher than 6%, it increases the difficulty of glass melting. Therefore, in this invention, the Al₂O₃ content is controlled at 2–6% (molar percentage), for example: 2%, 3%, 4%, 5%, 6%, etc.

[0121] In the glass system of this invention, BaO is an outer network component, and it has the functions of increasing the refractive index and acting as a flux. Simultaneously, the addition of BaO can improve the crystallization properties of the glass. When the BaO content exceeds 3%, the refractive index will increase beyond a certain range. Therefore, the BaO content, in molar percentage, should be controlled between 0% and 3%, for example: 0.5%, 1%, 2%, 2.5%, etc.

[0122] In the glass system of this invention, ZnO acts as an outer network layer. A small amount of ZnO can improve the crystallization properties of the glass, and in particular, ZnO is beneficial for reducing the sag temperature. The more ZnO introduced, the more significant the reduction in the sag temperature. When the ZnO content exceeds 2%, the refractive index of the glass increases, making it difficult to meet the refractive index difference between the core layer and the cladding glass. Therefore, the ZnO content, in molar percentage, should be controlled between 0% and 2%, for example, 0.5%, 1%, 1.5%, etc.

[0123] K₂O and Na₂O are network exogenous components in polarizing glass precursors. The two oxides have similar functions, lowering the glass melting temperature and sag temperature. The simultaneous addition of both oxides creates a hybrid effect, reducing the glass's crystallization tendency. When the Na₂O content is less than 2%, the reduction in glass transition temperature is not significant and fails to achieve the desired effect, as Na₂O has low solubility in this glass system. If the Na₂O content exceeds 4%, the crystallization tendency will intensify. Adding an appropriate amount of K₂O can have a hybrid effect, but excessive amounts should be avoided, as too much K₂O will also increase the crystallization tendency. Therefore, the Na₂O content, by molar percentage, should be controlled at 2–4%, for example: 2.5%, 3%, 3.5%, etc.; the K₂O content should be controlled at 0–2%, for example: 0.5%, 1%, 1.5%, etc.

[0124] In this invention, the refractive index nd2 of the second multi-component glass is 1.52 or less; the glass transition temperature Tg2 of the second multi-component glass is 580°C or less; and the coefficient of linear thermal expansion α2 of the second multi-component glass at 100–300°C is 80 × 10⁻⁶. -7 / ℃ below.

[0125] In this invention, the acid resistance D of the second multi-component glass A Grade 1, water resistance stability D W It is classified as Grade 1 or 2; the density of the second multi-component glass is not more than 2.5 g / cm³. 3 .

[0126] The first and second multi-component glasses provided by this invention do not intentionally introduce other coloring elements besides the components mentioned above: V, Mo, Cr, Mn, Fe, Co, Ni, Cu, and Ag. Simultaneously, they do not intentionally introduce compounds containing the following harmful elements: Th, Cd, Tl, Os, Be, Se, and fluorides.

[0127] The optical glass of this invention does not contain Ta2O5, resulting in high raw material costs and poor environmental friendliness. When using the same melting process, glass containing Ta2O5 has relatively lower transmittance, leading to increased optical fiber loss.

[0128] Furthermore, the first multi-component optical glass of the present invention does not contain Al2O3. In the first-component optical glass, the introduction of Al2O3 may introduce impurity absorption peaks (especially in the ultraviolet region), affecting light transmittance. In addition, Al2O3 increases melt viscosity, which may hinder bubble removal and increase the risk of defects in the glass.

[0129] In addition, the first multi-component optical glass of the present invention may not contain TiO2 and / or Nb2O5. TiO2 and / or Nb2O5 are prone to react with platinum, which causes the glass transmittance to decrease and makes it difficult to meet the requirements of long-distance transmission of lighting optical fiber.

[0130] <Second aspect>

[0131] A second aspect of the present invention provides a method for fabricating an illumination optical fiber according to the first aspect of the present invention, specifically, the illumination optical fiber can be obtained by drawing a rod and tube. The diameter of the core glass rod and the inner wall thickness of the cladding glass tube are calculated in advance based on the core occupancy rate.

[0132] Specifically, the method for fabricating the illumination optical fiber includes the following steps:

[0133] The raw materials for the first multi-component glass are mixed and made into a core glass rod.

[0134] The raw materials for the second multi-component glass are mixed and made into cladding glass tubes.

[0135] The core glass rod and the cladding glass tube are nested together, placed in a drawing tower heating furnace, vacuumed and heated, and then drawn to obtain an illumination optical fiber.

[0136] In this invention, the preparation method of the core glass rod or cladding glass tube includes weighing each component according to the proportion, mixing them evenly, melting them, and then pouring them into the forming mold of the core glass rod or the forming mold of the cladding glass tube to obtain the core glass rod or the cladding glass tube.

[0137] Specifically, the fiber drawing process using the rod-tube method involves first calculating the dimensions of the fiber core preform and the cladding glass tube to ensure that their numerical apertures reach at least 70%. Then, the fibers are processed and polished to achieve a smooth surface free of cracks and defects.

[0138] After the core preform and cladding glass tube are assembled together, they are clamped at the top of the fiber drawing machine and heated. When the temperature exceeds 900℃, the lower end of the preform and tube assembly gradually softens and melts, adhering tightly and converging into a conical viscous body. Heating continues, and when the temperature exceeds 950℃, fiber drawing is performed. The drawing temperature is fixed between 950℃ and 1000℃, and the drooping monofilament is wound around rollers for traction. The fiber diameter is monitored in real time using a laser diameter gauge, and the traction machine speed (10-50m / min) and preform feed rate (0.5-2mm / min) are adjusted to achieve precise control of the fiber diameter.

[0139] <Third aspect>

[0140] A third aspect of the present invention provides the use of the illumination optical fiber according to the first aspect of the present invention in an endoscope.

[0141] Example

[0142] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0143] The components of fiber core 1-20 in Table 1-4 are weighed and mixed evenly to prepare a batch material. The batch material is then placed in a crucible made of precious metal Pt and melted at 1280°C. After stirring and clarifying at 1380°C for 15 hours, the temperature is lowered to 1230°C and held for 1 hour before being removed from the furnace and poured into a mold to form the fiber. After glass annealing and cooling, the fiber glass core material of this application can be obtained.

[0144] The components of cladding 1-20 in Table 5-8 are weighed and mixed evenly to prepare a batch material. The batch material is then placed in a crucible made of precious metal Pt and melted at 1450°C. After stirring and clarifying at 1500°C for 20 hours, the temperature is lowered to 1400°C and held for 1 hour before being removed from the furnace and poured into a mold to form the fiber optic glass cladding of this application. After the glass is annealed and cooled, the fiber optic glass cladding of this application can be obtained.

[0145] Optical fiber drawing using the rod-tube method begins with calculating the dimensions of the fiber core preform and the cladding glass tube to ensure a numerical aperture ratio of over 70%. These are then processed and polished to achieve a smooth surface free of cracks and defects. The rod and tube are then assembled and clamped at the top of the optical fiber drawing machine for heating. When the temperature exceeds 900℃, the lower end of the rod-tube assembly gradually softens and melts, forming a conical, viscous body. Heating continues until the temperature exceeds 950℃, at which point drawing begins. The drawing temperature is then fixed at approximately 975℃, and the drooping monofilament is wound around rollers for traction. The fiber diameter is monitored in real-time using a laser diameter gauge, and the traction machine speed (10-50 m / min) and rod feed rate (0.5-2 mm / min) are adjusted to precisely control the fiber diameter to below 55 μm.

[0146] Performance testing

[0147] 1. Refractive index nd

[0148] The refractive index nd of the obtained optical glass was determined according to the test method of GB / T7962.1-2010. The nd listed in the table are the data after annealing at -4℃.

[0149] 2. Glass transition temperature (Tg) and coefficient of linear expansion

[0150] The measurement shall be performed according to the method specified in GB / T 7962.16.

[0151] 3. Water resistance D W Acid resistance D A (Powder method)

[0152] 1) Water resistance D W

[0153] 10 g ± 0.0001 g of powdered glass (passed through a 40-32 mesh sieve) with a particle size of 450-560 μm was placed in a filter. The glass was then immersed in a quartz glass flask containing 80 mL of distilled water (pH 6.5-7.5) and kept at a constant temperature of 98-100 °C for 60 minutes. All glass particles were then transferred to a pre-weighed filter, washed with 80 mL of anhydrous ethanol, and dried at 120 ± 5 °C to constant weight. The percentage of glass leaching was calculated using the following formula:

[0154]

[0155] In the formula: D W —Percentage of glass leaching, %;

[0156] B—mass of the filter and sample, in g;

[0157] C—mass of the filter and the etched sample, in g;

[0158] A—Filter mass, g.

[0159] Based on the percentage of water leaching by mass, the water resistance stability D of optical glass is determined. W They are divided into six categories, as shown in Table A below:

[0160] Table A

[0161]

[0162] 2) Acid resistance D A

[0163] With D W The determination method is the same; a 0.01 mol / L nitric acid aqueous solution is added to the flask for treatment, and the glass leaching percentage is calculated according to the following formula:

[0164]

[0165] In the formula: D A —Percentage of glass leaching, %;

[0166] B—mass of the filter and sample, in g;

[0167] C—mass of the filter and the etched sample, in g;

[0168] A—Filter mass, g.

[0169] Based on the percentage of leaching by mass, the acid resistance stability D of optical glass is determined. A They are divided into six categories, as shown in Table B below:

[0170] Table B

[0171]

[0172] 4. Density

[0173] The density of the obtained optical glass was determined according to the test method of GB / T7962.20-2010.

[0174] The glass composition, refractive index nd, transition temperature Tg, coefficient of linear expansion, density ρ, and water resistance D of the core and cladding used in Examples 1-26 were analyzed. W Acid resistance DA Examples of optical fibers and their performance parameters from Examples 1-26 are listed in Tables 1-8.

[0175] Table 1 Glass composition and performance parameters of fiber cores 1-5

[0176] Components (mol%) Core 1 Core 2 Core 3 Core 4 Core 5 <![CDATA[SiO2]]> 39 38 42 40 40 <![CDATA[ZrO2]]> 5 4.5 5 4 6 <![CDATA[B2O3]]> 10 11.5 7 9 8.5 <![CDATA[La2O3]]> 10 8.5 8.5 9.5 8.5 BaO 29 30.5 29 31.5 30 ZnO 5 5.5 6.5 5 5.5 <![CDATA[Na2O]]> 2 1.5 2 1 1.5 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 49 49.5 49 49 48.5 <![CDATA[Refractive index nd1]]> 1.72626 1.72153 1.72318 1.72416 1.72880 <![CDATA[D W (Level) 1 1 1 1 1 <![CDATA[D A (Level) 3 3 3 3 2 <![CDATA[Specific gravity (g / cm 3 )]]> 4.43 4.33 4.39 4.4 4.47 <![CDATA[Glass transition temperature Tg1 (°C)]]> 655 668 656 682 670 <![CDATA[Coefficient of thermal expansion α1 (×10 -7 / °C)]]> 96.4 97.3 96.5 98.2 97.1

[0177] Table 2 Glass composition and performance parameters of fiber core 6-10

[0178] Components (mol%) Core 6 Core 7 Core 8 Core 9 Core 10 <![CDATA[SiO2]]> 38.5 38 40 39.5 39 <![CDATA[ZrO2]]> 4.5 4 5 4.5 6 <![CDATA[B2O3]]> 9 12 9 8.5 9.5 <![CDATA[La2O3]]> 8 9.5 8 10 9.5 BaO 31 29 30 30 29 ZnO 8 5.5 7 6 5.5 <![CDATA[Na2O]]> 1 2 1 1.5 1.5 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 47.5 50 49 48 48.5 <![CDATA[Refractive index nd1]]> 1.73169 1.72110 1.72518 1.72693 1.72677 <![CDATA[D W (Level) 1 1 1 1 1 <![CDATA[D A (Level) 3 3 3 3 2 <![CDATA[Specific gravity (g / cm 3 )]]> 4.52 4.36 4.41 4.45 4.44 <![CDATA[Glass transition temperature Tg1 (°C)]]> 685 662 680 672 669 <![CDATA[Coefficient of thermal expansion α1 (×10 -7 / °C)]]> 97.6 96.6 96.8 97.5 96

[0179] Table 3 Glass composition and performance parameters of fiber core 11-15

[0180] Components (mol%) Core 11 Core 12 Core 13 Core 14 Core 15 <![CDATA[SiO2]]> 38.5 41 38 39 41 <![CDATA[ZrO2]]> 4.5 4 4.5 6 5 <![CDATA[B2O3]]> 7.5 8.5 8.5 9.5 7.5 <![CDATA[La2O3]]> 8.5 9 8 9 8.5 BaO 35 30.5 31.5 30 29.5 ZnO 5 5 8 5.5 6 <![CDATA[Na2O]]> 1 2 1.5 1 2.5 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 46 49.5 46.5 48.5 48.5 <![CDATA[Refractive index nd1]]> 1.74123 1.72026 1.73987 1.72723 1.72566 <![CDATA[D W (Level) 1 1 1 1 1 <![CDATA[D A (Level) 3 3 3 2 3 <![CDATA[Specific gravity (g / cm 3 )]]> 4.68 4.27 4.65 4.46 4.42 <![CDATA[Glass transition temperature Tg1 (°C)]]> 678 656 671 688 652 <![CDATA[Coefficient of thermal expansion α1 (×10 -7 / °C)]]> 100 98.6 99.2 96.2 98.7

[0181] Table 4 Glass composition and performance parameters of fiber core 16-20

[0182] Components (mol%) Core 16 Core 17 Core 18 Core 19 Core 20 <![CDATA[SiO2]]> 41 40 38.5 39.5 42 <![CDATA[ZrO2]]> 5.5 5 5 4 5 <![CDATA[B2O3]]> 7 7.5 11 10.5 7.5 <![CDATA[La2O3]]> 8 9 9.5 8 8 BaO 31 29 29.5 29 29.5 ZnO 6 7.5 5 7 5.5 <![CDATA[Na2O]]> 1.5 2 1.5 2 2.5 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 48 47.5 49.5 50 49.5 <![CDATA[Refractive index nd1]]> 1.72823 1.73213 1.72096 1.72017 1.72055 <![CDATA[D W (Level) 1 1 1 1 1 <![CDATA[D A (Level) 3 3 2 3 2 <![CDATA[Specific gravity (g / cm 3 )]]> 4.47 4.53 4.3 4.26 4.28 <![CDATA[Glass transition temperature Tg1 (°C)]]> 675 658 670 660 650 <![CDATA[Coefficient of thermal expansion α1 (×10 -7 / °C)]]> 98.5 98.8 96.3 96.5 97.3

[0183] As can be seen from Tables 1-4, the refractive index nd1 of the first multi-component glass used to prepare the core fiber of the present invention is 1.72 or higher, specifically 1.72-1.75; the glass transition temperature Tg1 of the first multi-component glass is 650℃ or higher; and the coefficient of linear thermal expansion α1 of the first multi-component glass at 100-300℃ is 96×10⁻⁶. -7 / ℃ or higher. Furthermore, the acid resistance stability D of the first multi-component glass... A Grade 3 or 2, water resistance stability D W It is classified as Grade 1; the density of the first multi-component glass is not more than 4.68 g / cm³. 3 .

[0184] Table 5 Glass composition and performance parameters of cladding layers 1-5

[0185] Components (mol%) Cladding 1 Cladding 2 Cladding 3 Cladding 4 cladding 5 <![CDATA[SiO2]]> 33 45 45 31 33 <![CDATA[B2O3]]> 58 42 40 60 57.5 <![CDATA[Al2O3]]> 3 5 5.7 2.5 2 BaO 1.5 2.5 2.5 1 2.5 ZnO 0.3 1.1 1.5 0.8 0.5 <![CDATA[K2O]]> 1.9 0.9 1.8 1.2 1.5 <![CDATA[Na2O]]> 2.3 3.5 3.5 3.5 3 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 91 87 85 91 90.5 <![CDATA[Refractive index nd2]]> 1.47632 1.49631 1.50880 1.47712 1.47882 <![CDATA[D W (Level) 1 2 2 2 2 <![CDATA[D A (Level) 1 1 1 1 1 <![CDATA[Specific gravity (g / cm 3 )]]> 2.26 2.41 2.45 2.27 2.29 <![CDATA[Glass transition temperature Tg2 (°C)]]> 557 547 531 546 553 <![CDATA[Coefficient of thermal expansion α2 (×10 -7 / °C)]]> 50 70.2 72.1 52 55.9

[0186] Table 6. Glass composition and performance parameters of cladding 6-10

[0187] Components (mol%) Encasing 6 Encasing 7 cladding 8 cladding 9 Cladding 10 <![CDATA[SiO2]]> 33 39 35 32 35 <![CDATA[B2O3]]> 56 51 53 58 55 <![CDATA[Al2O3]]> 6 5.5 2.8 4.5 3 BaO 1.4 0 3 0.2 2.8 ZnO 0 0.5 1.7 1.2 0 <![CDATA[K2O]]> 1.1 0.5 1 1.6 1.2 <![CDATA[Na2O]]> 2.5 3.5 3.5 2.5 3 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 89 90 88 90 90 <![CDATA[Refractive index nd2]]> 1.48632 1.48132 1.49131 1.48211 1.48176 <![CDATA[D W (Level) 1 1 2 1 2 <![CDATA[D A (Level) 1 1 1 1 1 <![CDATA[Specific gravity (g / cm 3 )]]> 2.38 2.31 2.39 2.35 2.33 <![CDATA[Glass transition temperature Tg2 (°C)]]> 569 558 540 549 562 <![CDATA[Coefficient of thermal expansion α2 (×10 -7 / °C)]]> 64.1 57.9 68.2 60.1 59.5

[0188] Table 7. Glass composition and performance parameters of cladding 11-15

[0189] Components (mol%) Cladding 11 Cladding 12 Cladding 13 Cladding 14 Cladding 15 <![CDATA[SiO2]]> 39 38 37 38.5 44 <![CDATA[B2O3]]> 51 52 53.5 52.5 40 <![CDATA[Al2O3]]> 2.5 3 3.5 3.8 5.8 BaO 2 2.5 1.3 2.5 2.8 ZnO 2 0.1 0.6 0.5 1.8 <![CDATA[K2O]]> 1 1.8 2 0 1.8 <![CDATA[Na2O]]> 2.5 2.6 2.1 2.2 3.8 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 90 90 90.5 91 84 <![CDATA[Refractive index nd2]]> 1.48169 1.48191 1.47896 1.47736 1.51431 <![CDATA[D W (Level) 2 2 2 1 2 <![CDATA[D A (Level) 1 1 1 1 1 <![CDATA[Specific gravity (g / cm 3 )]]> 2.32 2.34 2.3 2.28 2.48 <![CDATA[Glass transition temperature Tg2 (°C)]]> 545 559 556 580 525 <![CDATA[Coefficient of thermal expansion α2 (×10 -7 / °C)]]> 59.1 58.6 56.5 55.2 76.1

[0190] Table 8

[0191] Components (mol%) Cladding 16 Cladding 17 Cladding 18 Cladding 19 cladding 20 <![CDATA[SiO2]]> 41 42 39.5 30 40 <![CDATA[B2O3]]> 46 41 44 55 44 <![CDATA[Al2O3]]> 4.7 6 6 5.5 5.6 BaO 3 3 3 2.2 2.8 ZnO 1.5 2 2 1.6 1.8 <![CDATA[K2O]]> 1.8 2 2 1.8 2 <![CDATA[Na2O]]> 2 4 3.5 3.9 3.8 total 100 100 100 100 100 <![CDATA[∑SiO2+B2O3]]> 87 83 83.5 85 84 <![CDATA[Refractive index nd2]]> 1.49586 1.51880 1.51630 1.50891 1.51380 <![CDATA[D W (Level) 2 2 2 2 2 <![CDATA[D A (Level) 1 1 1 1 1 <![CDATA[Specific gravity (g / cm 3 )]]> 2.4 2.5 2.49 2.46 2.47 <![CDATA[Glass transition temperature Tg2 (°C)]]> 548 518 523 527 521 <![CDATA[Coefficient of thermal expansion α2 (×10 -7 / °C)]]> 69.2 80 78.2 74.1 75.2

[0192] As can be seen from Tables 5-8, the refractive index nd2 of the second multi-component glass used in the preparation of the cladding in this invention is below 1.52, specifically between 1.47 and 1.52. The glass transition temperature Tg2 of the second multi-component glass is below 580℃, and the coefficient of linear thermal expansion α2 of the second multi-component glass at 100–300℃ is 80 × 10⁻⁶. -7 / ℃ or below. In this invention, the acid resistance stability D of the second multi-component glass is... A Grade 1, water resistance stability D W It is classified as Grade 1 or 2; the density of the second multi-component glass is not more than 2.5 g / cm³. 3 .

[0193] Table 9. Optical fibers and performance parameters in Examples 1-7

[0194]

[0195] Table 10. Optical fibers and performance parameters in Examples 8-13

[0196]

[0197] Table 11 Optical fibers and their performance parameters in Examples 14-20

[0198]

[0199] Table 12 Fibers and Performance Parameters in Examples 21-26

[0200]

[0201] As shown in Table 9-12, the numerical aperture NA of the illumination fiber is greater than 0.8; the difference in the linear thermal expansion coefficient Δα of the illumination fiber is 16 × 10⁻⁶. -7 / ℃~50×10 -7 / ℃; in the cross-section of the lighting optical fiber, the core occupancy is greater than 70%; the single filament diameter of the lighting optical fiber is less than 55μm. The lighting optical fiber of the present invention is not easily broken when repeatedly bent or twisted, has high optical transmission efficiency, and has the properties of bend resistance and long service life.

[0202] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0203] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An illumination optical fiber, characterized by, The illumination optical fiber comprises a core and a cladding, wherein, the core is derived from a first multi-component glass, and the cladding is derived from a second multi-component glass; and the first multi-component glass comprises the following components in mole percentage: SiO2: 38-42%, preferably 39-41%; ZrO2: 4-6%, preferably 4.5-5.5%; B2O3: 7-12%, preferably 8-11%; La2O3: 8-10%, preferably 8.5-9.5%; BaO: 29-35%, preferably 30-33%; ZnO: 5-8%, preferably 6-7.5%; Na2O: 1-2.5%, preferably 1.5-2%; the second multi-component glass comprises the following components in mole percentage: SiO2: 30-45%, preferably 33-40%; B2O3: 40-60%, preferably 42-58%; Al2O3: 2-6%, preferably 3-5%; BaO: 0-3%, preferably 1-2%; ZnO: 0-2%, preferably 0.1-1%; K2O: 0-2%, preferably 0.1-1% Na2O: 2-4%, preferably 2.5-3.5%.

2. The illumination optical fiber of claim 1, wherein, The numerical aperture NA of the illumination optical fiber is greater than 0.8; The difference Δα in linear thermal expansion coefficient of the illumination optical fiber is 16 x 10 -7 / °C to 50 x 10 -7 / °C, and the difference Δα in linear thermal expansion coefficient is a value obtained by subtracting the linear thermal expansion coefficient α2 of the second multi-component glass at 100 to 300°C from the linear thermal expansion coefficient α1 of the first multi-component glass at 100 to 300°C. The core occupancy of the illumination optical fiber is greater than 70% on the cross section of the illumination optical fiber, wherein the core occupancy is the ratio of the area occupied by the core to the area occupied by the illumination optical fiber; The single fiber diameter of the illumination optical fiber is below 55 μm.

3. Illumination optical fiber according to claim 1 or 2, characterized in that, In the first multi-component glass, the sum of SiO2 and B2O3, ∑SiO2+B2O3, is 46-50% in mole percentage.

4. Illumination optical fiber according to any of claims 1-3, characterized in that, The refractive index nd1 of the first multi-component glass is above 1.72; The glass transition temperature Tg1 of the first multi-component glass is above 650℃; The first multi-component glass has a linear thermal expansion coefficient a1 of 96 x 10 -7 / °C or more at 100 to 300°C; the first multi-component glass has an acid resistance stability D A of Grade 3 or more, and a water resistance stability D W of Grade 1. The first multi-component glass has a density of no more than 4.68 g / cm 3 .

5. Illumination optical fiber according to any of claims 1-4, characterized in that In the second multi-component glass, the sum of SiO2 and B2O3, ∑SiO2+B2O3, is 83-91% in mole percentage.

6. Illumination optical fiber according to any of claims 1-5, characterized in that, The refractive index nd2 of the second multi-component glass is below 1.52; The glass transition temperature Tg2 of the second multi-component glass is below 580℃; The second multicomponent glass has a linear thermal expansion coefficient a2 of 80 x 10 -7 -6 / °C or less at 100-300°C.

7. Illumination optical fiber according to any of claims 1-6, characterized in that, the acid resistance stability D of the second multi-component glass A is 1 or 2; the water resistance stability D W is 1 or 2; The second multi-component glass has a density of no more than 2.5 g / cm 3 .

8. A method of manufacturing an illumination optical fiber according to any one of claims 1-7, characterized in that, comprising the following steps: mixing raw materials of the first multi-component glass and making a core material glass rod, mixing raw materials of the second multi-component glass and making a cladding glass tube, sleeving the core material glass rod and the cladding glass tube, and putting them into a drawing tower heating furnace to vacuumize and heat, and then drawing to obtain the illumination optical fiber.

9. The preparation method according to claim 8, characterized in that, The method for preparing the core material glass rod or the cladding glass tube comprises weighing and mixing the components in proportion, melting, and then pouring into a forming mold of the core material glass rod or a forming mold of the cladding glass tube to obtain the core material glass rod or the cladding glass tube.

10. Use of the illumination optical fiber according to any one of claims 1-7 in an endoscope.

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