Multi-section plastic optical fiber, electronic endoscope lighting system and electronic endoscope

Abstract

The invention aims to provide a multi-section plastic optical fiber. The multi-section plastic optical fiber comprises a tail-end plastic optical fiber, a lens unit and a head-end plastic optical fiber, the tail-end plastic optical fiber is connected with the head-end plastic optical fiber through the lens unit, and the diameter FLE of the tail-end plastic optical fiber and the diameter FLH of the head-end plastic optical fiber meet the relation of FLE > FLH. The multi-section plastic optical fiber provided by the invention is suitable for an electronic endoscope illumination system, is particularly suitable for endoscopes which can be inserted into bile ducts, pancreatic ducts and eyes, and has the advantages of high numerical aperture, large quantity of transmitted light and small diameter of the insertion part. In addition, the multi-section plastic optical fiber can further reduce the manufacturing cost of the endoscope and simplify the design of the lighting device.

Description

Technical Field

[0001] The invention relates to a multi-segment plastic optical fiber and an electronic endoscope lighting system and an electronic endoscope using the same. Background Art

[0002] The illumination system used in electronic endoscopes is composed of a light source and a light guide that transmits light from the light source to the distal end and illuminates the object to be illuminated. The light guide uses a single optical fiber or is made by bundling multiple optical fibers to increase the amount of light transmitted.

[0003] Optical fibers are roughly divided into glass optical fibers and plastic optical fibers. In recent years, due to the miniaturization of photographic devices represented by CCD (Charge Coupled Device), the outer diameter of the endoscope observation probe can be made thinner, and the light guide configured in the probe also has a demand for a thinner outer diameter. In addition, since the diameter of the endoscope observation probe can be made thinner, it has become possible to directly observe the inside of extremely fine lumens such as the bile duct and pancreatic duct, or the inside of the eyeball, joints, etc., which could not be inserted into the probe in the past. The diameter of the bile duct and pancreatic duct is about 5mm to 10mm, which is very thin, so the outer diameter of the endoscope inserted into these lumens is limited to 3mm to 4mm. When performing minimally invasive surgery on the eyes, joints, etc., the diameter of the endoscope is related to the size of the wound area, which further affects the patient's recovery time. Using an endoscope with a thinner diameter is conducive to reducing the wound area and shortening the recovery time. The outer diameter of the endoscope inserted into the eyeball and joints is further limited to 1mm to 2.5mm. For this reason, an optical fiber that can transmit a large amount of light while maintaining a relatively small diameter is required.

[0004] However, when using glass optical fiber, even if the fiber diameter is the same as that of plastic optical fiber, the amount of transmitted light is reduced due to its small core diameter, and the brightness required for observation cannot be achieved.

[0005] However, compared with glass optical fiber, plastic optical fiber has a larger core diameter and a larger numerical aperture in the light transmission part even with the same fiber diameter, so a larger amount of light can be transmitted. At the same time, as the numerical aperture increases, the allowable reflection angle in the optical fiber also increases, so the reduction in light intensity during bending can be reduced. In addition, it has the characteristic of not being easily broken even when bent. As such, it is hoped that plastic optical fiber with a higher numerical aperture can be used as plastic optical fiber for medical device lighting.

[0006] However, when the light guide is inserted into the above-mentioned thinner lumen or part, due to the thin diameter of the plastic optical fiber used, there are problems such as small amount of transmitted light and poor lighting effect.

[0007] Patent document 1 describes a method in which an optical fiber is processed into a light guide, and the coupling parts of two optical fibers of different thicknesses are processed into thicknesses that match the light guide. Since the length of the light guide part is relatively long, the length of the endoscope needs to be increased. At the same time, the thickness of the optical fiber may be uneven when it is tapered, and the optical fibers at both ends need to be processed separately, thereby reducing the light transmission amount accordingly, and there is also the problem of difficult design.

[0008] Therefore, balancing large transmitted light volume and small optical fiber diameter is a difficult problem that needs to be solved urgently.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent No. 5492026 Summary of the invention

[0012] In order to solve the need for optical fiber materials with both large light transmission volume and small diameter in the manufacture of electronic endoscope lighting systems, the present invention adopts materials with excellent performance and a good balance in cost.

[0013] The present invention provides a multi-segment plastic optical fiber, comprising a tail end plastic optical fiber, a lens unit, and a head end plastic optical fiber; the tail end plastic optical fiber is connected to the head end plastic optical fiber through the lens unit, and the diameter FL of the tail end plastic optical fiber is E and the diameter FL of the head end plastic optical fiber H Meet FL E >FL H relationship.

[0014] The present invention also provides an electronic endoscope lighting system, which contains at least one group of the aforementioned multiple-segment plastic optical fibers.

[0015] The present invention also provides an electronic endoscope, which comprises the electronic endoscope lighting system described above.

[0016] The multi-segment plastic optical fiber provided by the present invention is suitable for use in electronic endoscope lighting systems, especially for endoscopes that can be inserted into bile ducts, pancreatic ducts, eyes, or joints, and has a high numerical aperture, a large amount of transmitted light, and a small insertion portion diameter. In addition, the use of multi-segment plastic optical fibers can further reduce the manufacturing cost of endoscopes and simplify the design of lighting devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the light beam movement.

[0018] 1. Plastic optical fiber at the tail end;

[0019] 2. Plastic optical fiber head end;

[0020] 3 lens units;

[0021] 4 Beam movement. DETAILED DESCRIPTION

[0022] In order to increase the amount of light entering and transmitted at the head end optical fiber part, the multi-segment plastic optical fiber of the present invention comprises a tail end plastic optical fiber, a lens unit and a head end plastic optical fiber. The tail end plastic optical fiber is connected to the head end plastic optical fiber through the lens unit, and the diameter FL of the tail end plastic optical fiber is E and the diameter of the plastic optical fiber at the head end FL H Meet FL E >FL H relationship.

[0023] In order to increase the amount of light entering from the light source, the diameter of the tail end plastic optical fiber, as the part that does not enter the human body, must be larger than the diameter of the head end plastic optical fiber. E Preferably, it is 120 to 2500 μm, more preferably 500 to 2500 μm. For an endoscope observation probe that can be inserted into the bile duct, pancreatic duct, eyeball, or joint, if a higher output brightness is required for the cavity and organ used, the diameter FL of the tail end plastic optical fiber is E More preferably, it is 750 to 2500 μm.

[0024] Considering the storage and operability in the observation probe of the endoscope, the diameter FL of the tip plastic optical fiber is preferably H is 100-1500 μm, and the diameter FL of the head end plastic optical fiber is further preferably H The diameter of the endoscope is preferably 100-1250 μm, more preferably 120-1000 μm. Furthermore, regarding the observation probe of the endoscope that can be inserted into the bile duct, pancreatic duct, eyeball, or joint, if the necessity of storing the plastic optical fiber together with the photographic device and the treatment forceps is considered, the diameter of the observation probe is preferably 6 mm or less, more preferably 4 mm or less. In addition, the diameter of the head end plastic optical fiber is preferably 120-500 μm.

[0025] In order to improve the lighting effect, the diameter FL of the tail end plastic optical fiber is preferably E FL is the diameter of the plastic optical fiber at the head end H It is more preferably 1.5 times or more, more preferably 2 times or more, and further preferably 3 times or more. Considering the balance between cost and performance, and causing unnecessary light transmission loss, it is more preferably 3 times or more and less than 5 times.

[0026] The plastic optical fiber of the present invention comprises a core layer and a cladding layer. The material of the core layer is preferably a (co)polymer with methyl methacrylate as the main component, and PMMA, a copolymer with methyl methacrylate as the main component, or a modified polymer such as glutaric anhydride and glutarimide obtained by macromolecular reaction with these, etc. The copolymer with methyl methacrylate as the main component is, for example, copolymerized with (meth)acrylate, (meth)acrylic acid, substituted styrene, N-substituted maleimide, etc. Furthermore, as (meth) acrylate, methacrylate, ethyl methacrylate, butyl methacrylate, tert-butyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, phenyl methacrylate, bornyl methacrylate, adamantyl methacrylate, etc. can be listed, styrene, methyl styrene, α-methyl styrene, etc. can be listed as substituted styrene, N-isopropyl maleimide, N-cyclohexyl maleimide, N-methyl maleimide, N-ethyl maleimide, N-o-methylphenyl maleimide, etc. can be listed as N-substituted maleimide. These copolymerization components can be used in a variety of ways, and components other than these can also be used in small quantities. In addition, it is also possible to contain stabilizers such as antioxidants in an appropriate amount without adversely affecting light transmittance. Among these polymers, PMMA is most preferred from the aspects of productivity, light transmittance, environmental resistance, etc.

[0027] The plastic optical fiber of the present invention preferably contains the following copolymer as a cladding layer:

[0028] Hexafluoropropylene 10-30% by weight

[0029] Tetrafluoroethylene 45-75% by weight

[0030] 1,1-Difluoroethylene 10-35% by weight

[0031] and 1 to 10% by weight of perfluoroalkyl vinyl ethers.

[0032] Among them, the fluorine composition weight ratio is 70-74%. Within the above-mentioned composition weight range, the polymer composition of the coating layer does not contain monomers with low fluorine content such as acrylate and methacrylate, and the bending resistance is within an appropriate range. In addition, the manufacture of fluoropolymers is also relatively easy. When using the coating layer within the above-mentioned composition range, the low refractive index and low crystallization (colorless and transparent) of the coating layer can be easily achieved. In addition, the coating layer and the (co)polymer of the methyl methacrylate main body in the core layer have excellent adhesion, and have excellent mechanical properties (bending resistance), adhesion, and heat resistance.

[0033] In order to further improve the mechanical properties and adhesion, it is preferred that the coating layer contains

[0034] Hexafluoropropylene 14-25% by weight

[0035] Tetrafluoroethylene 49-70% by weight,

[0036] 1,1-Difluoroethylene 14-30% by weight

[0037] The fluorine composition weight ratio of the coating layer is preferably 71 to 74%.

[0038] The thickness of the coating layer is preferably 2 to 20 μm, more preferably 3 to 16 μm, further preferably 4 to 12 μm, and further preferably 4 to 10 μm.

[0039] In order to improve the molding stability and take into account the flexibility and adhesion of the optical fiber, it is preferred that the outer side of the above-mentioned coating layer further has one or more coating layers, and the outermost coating layer contains

[0040] Ethylene 10-35% by weight,

[0041] Tetrafluoroethylene 45-69% by weight,

[0042] 20 to 45% by weight of hexafluoropropylene, and

[0043] A copolymer containing 0.01 to 10% by weight of a fluorovinyl compound represented by formula (1).

[0044] CH2=CX1(CF2)nX2 (1)

[0045] (In the formula, X1 represents a fluorine atom or a hydrogen atom, X2 represents a fluorine atom, a hydrogen atom or a carbon atom, and n is an integer of 1 to 10.)

[0046] Furthermore, in order to prevent the coating from being too soft and causing adhesion problems during curling, it is preferred that the outer side of the outermost coating also has a protective layer. The structure of the protective layer can be a structure in which 1,1-difluoroethylene / tetrafluoroethylene copolymer, 1,1-difluoroethylene / hexafluoroacetone copolymer, 1,1-difluoroethylene homopolymer and other 1,1-difluoroethylene (co)polymers, ethylene / tetrafluoroethylene / hexafluoropropylene (co)polymers, or (co)polymers based on methyl methacrylate as the core, nylon 12 and other polymers are coated with a thickness of 2 to 100 μm. Pigments such as carbon black can be added to the protective layer for coloring.

[0047] The head end and tail end plastic optical fiber of the present invention can be manufactured in the same manner as the usual manufacturing method. Preferably, a composite spinning method is used, for example, in which the core material and the cladding material are ejected from a composite die head for concentric composite in a heated and molten state to form a two-layer core-sheath structure of core / cladding. Then, in order to improve the mechanical properties, a stretching treatment of 1.2 to 3 times is usually performed to produce a plastic optical fiber. In order to improve the transparency of the core material, a continuous melt composite spinning method is more preferably used in which a series of steps such as monomer purification, polymerization, melt composite with the cladding material, and stretching treatment are performed in a closed system. In addition, in the case of setting a protective layer, a three-layer blended composite spinning method is preferably used.

[0048] When the plastic optical fiber of the present invention has the above-mentioned protective layer, the outer side of the protective layer may also have a coating layer. The coating layer contains polyethylene, polypropylene or their copolymers, blends, olefin polymers containing organosilyl groups, ethylene-vinyl acetate, polyvinyl chloride, polyvinylidene fluoride, nylon 12 and other polyamide resins, polyester resins, nylon elastomers, polyester elastomers or polyurethane resins, fluororesins and other resins to make a cord. The coating layer can be one layer or multiple layers. When there are multiple layers, tensile materials such as polyaromatic amide Kevlar can be sandwiched between them. These coating materials may contain flame retardants, as well as stabilizers such as antioxidants, aging agents, and ultraviolet stabilizers. Furthermore, the coating layer can be formed by a known method such as a melt extrusion molding method using a crosshead die. If there is no above-mentioned protective layer, the outer side of the outermost coating layer may be covered with the above-mentioned coating layer.

[0049] In order to improve the light beam conductivity between the head-end optical fiber and the tail-end optical fiber, it is preferred that the lens unit has a focusing effect. The material of the lens unit can be glass or plastic. The glass materials used in the optical system include optical glass, substrate glass, and lens glass. As optical glass, BK7, SF10, synthetic quartz, etc. can be used. As substrate glass, "Pyrex" (registered trademark) used as a plate glass material, glass called white board and blue board can be used. In addition, as lens glass, crown glass and leaded glass can be used, but they are not limited to these. In addition, as optical plastics, there are acrylic, styrene, polycarbonate, polyolefin, etc., but they are not limited to these. The refractive index is preferably 1.3 to 1.9, and more preferably 1.45 to 1.85.

[0050] Preferably, the lens curved surface of the lens unit includes at least one of a spherical surface, an aspherical surface, a square surface, or a wedge shape.

[0051] In order to reduce the loss of light during transmission, it is preferred that the diameter d of the lens unit is equal to the diameter FL of the plastic optical fiber at the tail end. E More than 1 times.

[0052] In order to further improve the light beam transmission efficiency between the head-end optical fiber and the tail-end optical fiber, it is preferred that the number of lenses in the lens unit is at least 1.

[0053] The numerical aperture NA of the tail end plastic optical fiber or the head end plastic optical fiber of the present invention is preferably greater than 0.5, and more preferably 0.5 to 0.65. When the numerical aperture is greater than 0.5, a lens with a relatively low curvature can be selected to prevent the undesirable situation that the light loss increases due to the thickening of the lens when a high curvature lens is used. In addition, the bending loss of the plastic optical fiber is small, and the amount of light is reduced. On the other hand, when the numerical aperture is less than 0.65, it is avoided that the manufacture of the fluoropolymer used as the cladding material becomes difficult in order to achieve a high numerical aperture. In order to further expand the irradiation range, the numerical aperture NA of the tail end plastic optical fiber or the head end plastic optical fiber is more preferably 0.6 to 0.65.

[0054] In order to reduce the reflection of the light beam in the tail optical fiber when it is transmitted to the head optical fiber interface, it is preferred that the lens unit side of the head plastic optical fiber has an anti-reflection and anti-transmission effect. The processing generally uses a coating process, and the coating method can use vacuum coating, sputtering coating or ion coating. The film is not particularly limited, and can use an anti-reflection film, an anti-transmission film, a semi-reflective and semi-transmissive film, etc.

[0055] In order to reduce the light transmission loss during the transmission process in the multi-segment optical fiber and improve the uniformity of the light beam transmitted to the head-end optical fiber, it is preferred that there is one tail-end plastic optical fiber and one head-end plastic optical fiber.

[0056] The present invention also provides an electronic endoscope lighting system, the lighting system contains at least one group of the above-mentioned multi-segment plastic optical fibers. The electronic endoscope lighting system is composed of a light source and a light guide that transmits light from the light source to the top end and irradiates the light to the irradiated object, and the light guide contains the multi-segment plastic optical fiber of the present invention. The light guide can be composed of a single group of multi-segment plastic optical fibers, or it can be composed of a plurality of groups of multi-segment plastic optical fibers in a bundle. The light emitted from the light source can be guided to the top end by the light guide. It is preferred to set an illumination lens at the top end. The light guided by the light guide is irradiated from the illumination lens set at the top end of the insertion portion to the inside of the object to be detected. In addition, in order to reduce the diameter of the observation probe, it is preferred that the number of groups of multi-segment optical fibers inserted into the light guide is less than 10 groups.

[0057] In the electronic endoscope lighting system as an embodiment of the present invention, the surface of the lighting lens on the plastic optical fiber side is preferably a flat surface. By making the surface a flat surface, the desired glass thickness can be studied without considering the curvature radius and the minimum lens thickness, so the cost can be kept low, and in addition, it is easy to adjust in order to keep the center position of the light guide consistent.

[0058] In addition, a space may be left between the end face of the light guide and the lens, or the shape of the end face of the plastic optical fiber inserted into the light guide may be consistent with the shape of the illumination lens, and they may fit tightly without any space. In addition, in the case where a space is left by the minimum lens thickness, it may be filled with air, transparent liquid, solid, or transparent resin.

[0059] The electronic endoscope illumination system according to the embodiment of the present invention may not have an illumination lens at the distal end portion. In other words, an illumination lens may be provided depending on the situation.

[0060] As the light source, a halogen lamp brighter than a normal incandescent lamp, a xenon lamp close to natural light with high brightness, an LED as a high brightness light source, etc. can be used. LED is preferably used as the light source because of its high brightness and low heat generated when it is turned on.

[0061] The present invention also provides an electronic endoscope, which includes the electronic endoscope lighting system described above, and can be particularly exemplified as an endoscope whose observation probe is inserted into the bile duct, pancreatic duct, eyeball or joint.

[0062] The present invention will be described in more detail below by way of examples. Furthermore, the produced plastic optical fibers were evaluated by the following methods.

[0063] (1) Light intensity:

[0064] The prepared bare fibers were prepared as the tail optical fiber and the head optical fiber, each with a length of 30 cm. The four end faces of the two fiber sections were treated with a hot plate. Then, a plano-convex lighting lens was fixed between the tail optical fiber and the head optical fiber, and its convex side was connected to the tail optical fiber surface. A 310-066LS light source of an optical power meter (Photom-206A manufactured by GRAY TECHNOS Co., Ltd.) was used to inject light from the other end of the tail optical fiber, and the light intensity emitted from the lighting head optical fiber was measured in a dark room.

[0065] (2) Transmission loss:

[0066] Halogen parallel light (wavelength 650nm) is used to measure the aperture brightness of the tail fiber output light and the head fiber output light. For each embodiment, the percentage of the ratio of the head fiber output light to the tail fiber output light is calculated, and the excellence of its transmission loss is judged according to the following rules. Among them, ◎ is the best, 0 is the second best, △ is average, and × is poor.

[0067] ◎: Less than or equal to 95%.

[0068] 0: Less than or equal to 97%, greater than 95%.

[0069] △: Less than or equal to 99%, greater than 97%.

[0070] ×: more than 99%.

[0071] The materials used in the embodiments and comparative examples are as follows:

[0072] Optical fiber type:

[0073] A: The composition of the cladding layer is 1,1-difluoroethylene (2F) / tetrafluoroethylene (4F) = 74.5 / 25.5, the refractive index of the cladding layer is 1.405, the refractive index of the core layer PMMA is 1.492, and the numerical aperture is 0.5;

[0074] B: The composition of the coating layer is 1,1-difluoroethylene (2F) / tetrafluoroethylene (4F) / hexafluoropropylene (6F) / perfluoropropyl vinyl ether copolymer = 19 / 59 / 19 / 3, the refractive index of the coating layer is 1.351, the refractive index of the core layer PMMA is 1.492, and the numerical aperture is 0.63;

[0075] C: The composition of the cladding layer is 1,1-difluoroethylene (2F) / tetrafluoroethylene (4F) = 86.5 / 13.5, the refractive index of the cladding layer is 1.419, the refractive index of the core layer PMMA is 1.492, and the numerical aperture is 0.46;

[0076] D: Glass optical fiber, numerical aperture: 0.14.

[0077] Lens unit:

[0078] E: Spherical plano-convex lens made by AlphaOptics, material ZLAF56B, refractive index 1.806;

[0079] F: Spherical plano-convex lens made by AlphaOptics, material H-LAK8A, refractive index 1.720.

[0080] G: Spherical plano-convex lens, made of PMMA, with a refractive index of 1.494.

[0081] [Example 1]

[0082] 1,1-Difluoroethylene (2F) / tetrafluoroethylene (4F) with the copolymerization ratio of Formula A as shown in Table 1 was supplied to the composite spinning machine as the cladding material. PMMA (measured at room temperature 25°C using an Abbe refractometer and having a refractive index of 1.492) produced by continuous bulk polymerization was supplied to the composite spinning machine as the core material, and the core and cladding were melt-spun at 235°C to obtain fibers. As a result, the light intensity emitted from the head end optical fiber was 7.10W.

[0083] [Examples 2 to 37]

[0084] Comparative Example 1, Examples 2-37 are the same as Example 1 except for the type and diameter of the plastic optical fiber at the tail end and its number, the type and diameter of the plastic optical fiber at the head end, the number of groups of the plastic optical fiber at the head end and the plastic optical fiber at the tail end, the type and number of lens units, and whether the lens unit side of the plastic optical fiber at the head end has anti-reflection and anti-reflection effect processing. The specific results and evaluations are shown in Table 1.

[0085] [Comparative Examples 1 to 3]

[0086] Comparative Example 1 adjusts the diameters of the tail end plastic optical fiber and the head end plastic optical fiber, and the diameter of the tail end plastic optical fiber is less than or equal to the diameter of the head end plastic optical fiber, and the rest is consistent with Example 6. From the specific results and evaluations recorded in Table 1, it can be seen that its light intensity is obviously not as good as that of the example.

[0087] In Comparative Example 2, no lens unit is used, and the rest is the same as in Example 1. Most of the outgoing light in the tail plastic optical fiber is scattered, resulting in poorer illumination brightness than in Example 1, and greatly increased transmission loss. As an optical fiber for medical device illumination, the illumination intensity is insufficient. The specific results and evaluations are shown in Table 1.

[0088] In Comparative Example 3, a glass optical fiber with a smaller core diameter is used as the head-end optical fiber, and the rest is consistent with Example 1. The illumination brightness is worse than that of the example, and the transmission loss is greatly increased. As an optical fiber for medical device illumination, the illumination intensity is insufficient. The specific results and evaluations are shown in Table 1.

[0089] Table 1

[0090]

[0091] In Examples 1 to 11, different diameter ratios of tail plastic optical fibers and head optical fibers are used, and all perform better than the comparative examples. The light intensity emitted by the head optical fiber of Examples 1, 6, 7, and 8 is better than that of Examples 2, 4, 5, 9, 10, and 11, and the results are better, taking into account the balance of light intensity and transmission loss, while satisfying the thinner head optical fiber diameter. Compared with Examples 8 and 9, head plastic optical fibers of different diameter ranges are used, and the effect of Example 8 is better.

[0092] In Examples 12 to 17 and 33, the formula of the tail plastic optical fiber is adjusted, cladding materials with different refractive indices are used, and the numerical aperture of the tail plastic optical fiber is changed. By comparing Examples 1, 4 to 8 and 12 to 17 and Examples 6, 15 and 33, it can be found that as the numerical aperture increases, the light intensity is improved. Among them, Examples 12, 15, 16, 17 and 33 are better than Examples 13 and 14, the diameter ratio of the tail plastic optical fiber to the head plastic optical fiber is in the preferred range, and the transmission loss is further reduced.

[0093] In Examples 18 to 23 and 34, the formula of the head-end plastic optical fiber is adjusted, cladding materials with different refractive indices are used, and the numerical aperture of the head-end plastic optical fiber is changed. By comparing Examples 1, 4 to 8 with Examples 18 to 23 and Examples 6, 21 and 34, it can be found that as the numerical aperture increases, the light intensity is improved. In Examples 18, 21, 22, 23 and 34, relative to Examples 19 and 20, the diameter ratio of the tail-end plastic optical fiber to the head-end plastic optical fiber is in a preferred range, and the transmission loss is further reduced.

[0094] Embodiments 24 to 29 simultaneously change the formula of the tail plastic optical fiber and the head plastic optical fiber, use a cladding material with a lower refractive index, increase the numerical aperture of the tail plastic optical fiber and the head plastic optical fiber, and compared with embodiments 1, 4 to 8, while maintaining low transmission loss, greatly improve the light intensity. Compared with embodiments 25 and 26, embodiments 24, 27, 28, and 29 take into account the balance of aperture brightness and transmission performance, while meeting the requirements of a thinner head optical fiber diameter, and have better effects.

[0095] Example 30 changes the formula of the lens unit and uses a plano-convex lighting lens. As a result, the light intensity emitted from the head-end optical fiber is 1.40W, which takes into account the balance between light intensity and transmission loss while meeting the requirement of a thinner head-end optical fiber diameter, resulting in excellent results.

[0096] Example 31 uses a non-spherical lens unit, and as a result, the light intensity emitted from the optical fiber at the head end is 2.23W, which is a good result.

[0097] Example 32 uses two lens units, and the light intensity emitted from the optical fiber at the head end is 2.13 W, which is a good result.

[0098] Compared with Example 35, Example 6 performs anti-reflection and anti-transmittance treatment on the plastic optical fiber connection section, so that the light intensity is improved and the transmission loss is reduced.

[0099] In Example 36, for one tail-end optical fiber, two head-end optical fibers were connected. As a result, the light intensity emitted from the head-end optical fiber was 2.06 W, which was slightly lower, but still better than the effect of the comparative example.

[0100] Example 37 used two groups of multi-segment plastic optical fibers, and the light intensity emitted from the optical fiber at the head end was 2.21 W, which is a good result.

[0101] In Example 38, the lens diameter is changed to 0.5 mm. Compared with Examples 6 and 38, when the diameter of the lens unit is more than one times the diameter of the plastic optical fiber at the tail end, the transmission loss is further reduced.

Claims

1. A multi-segment plastic optical fiber, comprising a tail end plastic optical fiber, a lens unit, and a head end plastic optical fiber; characterized in that: The tail end plastic optical fiber is connected to the head end plastic optical fiber through the lens unit, and the diameter FL of the tail end plastic optical fiber is E and the diameter FL of the head end plastic optical fiber H Meet FL E >FL H relationship.

2. The multi-segment plastic optical fiber according to claim 1, characterized in that: The diameter FL of the plastic optical fiber at the tail end E 120-2500μm.

3. The multi-segment plastic optical fiber according to claim 1, characterized in that: The diameter FL of the head end plastic optical fiber H 100-1500μm.

4. The multi-segment plastic optical fiber according to claim 1, characterized in that: The diameter FL of the plastic optical fiber at the tail end E is the diameter FL of the head end plastic optical fiber H More than 1.5 times of.

5. The multi-segment plastic optical fiber according to claim 4, characterized in that: The diameter FL of the plastic optical fiber at the tail end E is the diameter FL of the head end plastic optical fiber H Less than 5 times.

6. The multi-segment plastic optical fiber according to claim 1, characterized in that: The lens unit has a light-collecting effect.

7. The multi-segment plastic optical fiber according to claim 1, characterized in that: The lens curved surface of the lens unit includes at least one of a spherical surface, an aspherical surface, a square surface, or a wedge shape.

8. The multi-segment plastic optical fiber according to claim 1, characterized in that: The diameter d of the lens unit is the diameter FL of the plastic optical fiber at the tail end. E More than 1 times.

9. The multi-segment plastic optical fiber according to claim 1, characterized in that: The number of lenses in the lens unit is at least one.

10. The multi-segment plastic optical fiber according to claim 1, characterized in that: The numerical aperture of the tail end plastic optical fiber or the head end plastic optical fiber is greater than 0.

5.

11. The multi-segment plastic optical fiber according to claim 1, characterized in that: The lens unit side of the head-end plastic optical fiber is processed to achieve anti-reflection and anti-transmission effects.

12. The multi-segment plastic optical fiber according to claim 1, characterized in that: There is one tail end plastic optical fiber and one head end plastic optical fiber.

13. An electronic endoscope lighting system, characterized in that: A plastic optical fiber comprising at least one group of plastic optical fibers according to any one of claims 1 to 12.

14. An electronic endoscope, characterized in that: Includes the electronic endoscope lighting system as described in claim 13.

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