JP2007178980A - Ferrule holder and eccentricity measuring apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ferrule holder and an eccentricity measuring apparatus that can fully clamp a ferrule and obtain a measurement of a stabilized eccentricity. <P>SOLUTION: The ferrule holder 10 is equipped with a sleeve 1 having a slit 1b in the longitudinal direction and having a through hole 1a for holding a ferrule 5 in which an optical fiber is inserted in the bore, and also equipped with a holder 2 having the sleeve 1 arranged inside. The sleeve 1 is arranged with a gap provided between it and the holder 2 and is fixed to the holder 2 with a joining member 3 interposed in the gap in a region 1c which is opposed to the slit 1b across the through hole 1a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a ferrule holder including a sleeve for holding a ferrule and an eccentricity measuring apparatus using the same.

  2. Description of the Related Art Conventionally, for example, a detachable optical connector has been used for optical connection between optical fibers in connection of optical fiber cables and optical fiber cords used for wiring in buildings and wiring to equipment.

  Such an optical connector is generally fitted from both the optical connector plug 20 as shown in FIG. 6A to which the ferrule for inserting and holding the tip of the optical fiber is fixed, and the optical connector plug facing each other. And an optical connector adapter.

  As shown in FIG. 6A, the ferrule 21 has a substantially cylindrical shape, and an optical fiber insertion hole 21 a that penetrates in the axial direction and inserts and holds the optical fiber 22 is provided therein. A tapered portion 21b whose inner diameter gradually increases toward the opening side is provided at the rear end portion of the optical fiber insertion hole 21a. By providing such a tapered portion 21b, when the optical fiber 22 is inserted into the optical fiber insertion hole 21a, the tip of the optical fiber 22 is prevented from being broken or broken due to contact with the end face of the ferrule 21. can do.

  Examples of the material of the ferrule 21 include ceramic materials such as zirconia, plastic materials and glass materials such as crystallized glass, borosilicate glass, and quartz.

  Moreover, the optical fiber 22 is comprised from the core 22a of the optical fiber 22, and the clad | crud 22b which covers this core 22a, as shown in FIG.6 (b). Such an opposing connection between the optical fibers 27 is performed by bringing the cores 22a into contact with each other.

  In recent years, when optical fibers are connected to each other with an optical connector adapter, it is desired to optically connect with a relatively low insertion loss of light.

  Here, the loss factors at the time of optical connection between optical fibers include, for example, the angular deviation between optical fibers, the eccentricity of the core center, the gap, the end face quality of the optical fiber, and the end face reflection. It is generally known that the amount of eccentricity of the core center between fibers causes the largest increase in insertion loss.

  For example, in the case of the optical connector plug 20 having the single-mode optical fiber 22, the eccentric amount of the core center between the optical fibers is the position of the center of the cross section with respect to the outer diameter of the ferrule 22 serving as a reference at the time of optical connection. This is a value generated due to a positional shift of the optical fiber 22 from the core center.

  Therefore, conventionally, in order to guarantee a low-loss optical connector plug, for example, an eccentricity measuring device such as a core-centered eccentricity measuring device or a core-centered eccentricity measuring system is used. The amount of eccentricity at the center of the core is measured and provided to the user as a standard value.

  In such a core-centered eccentricity measuring apparatus (first conventional example), for example, as shown in FIG. 8, first, a ferrule between the V-groove 31 as the ferrule holder 30 and the pressing member 32 is used. Light is passed through the ferrule 33 with the 33 fixed, and the core center of the optical fiber 34 is enlarged by a lens and taken into the image processing apparatus. Next, the ferrule 33 is rotated by a predetermined angle on the V-groove 31, and the core center of the optical fiber 34 is enlarged again by the lens and taken into the image processing apparatus. Normally, the core center of the optical fiber 34 is estimated by performing such an operation four times and performing image processing on the position of the core center of the optical fiber 34 for each rotation by the image processing apparatus. The amount of eccentricity is measured from the center (see Patent Document 1).

As a second conventional example, a ferrule holder using a sleeve has been proposed (see Patent Document 2).
Japanese Patent Laid-Open No. 10-227619 Japanese Patent Laid-Open No. 8-29642

  However, the ferrule holder 30 in the first conventional example has a structure in which the cylindrical ferrule 33 is fixed on a total of three surfaces, that is, two surfaces of the V-groove 31 and one surface of the pressing member 32. It was difficult to fix. Therefore, in the conventional ferrule holder 30, the reproducibility of the measured value is poor, and it is easy to be affected by the roundness of the outer peripheral surface of the ferrule 33, so that it is difficult to accurately measure the eccentric amount. There was a problem.

  Further, in the conventional ferrule holder 40 in the second example, the stopper 43 is press-fitted and fixed to the inner hole at the tip of the split sleeve 41 and the holder 42 is press-fitted and fixed to the outer periphery. Therefore, for example, when the ferrule 44 is inserted obliquely into the inner hole of the split sleeve 41 with respect to the optical axis of the optical fiber, the outside of the ferrule 44 is larger than the diameter of the inner hole of the split sleeve 41. There was a possibility that the inner diameter of the inner diameter of the inner diameter was excessively expanded, resulting in variations in the measured amount of eccentricity.

  The present invention has been made in view of the above problems, and has a sleeve having a slit in the longitudinal direction and a through hole for holding a ferrule into which an optical fiber is inserted into an inner hole, and the sleeve. And a holder disposed therein, wherein the sleeve is disposed with a gap between the sleeve and the slit in the gap in a region facing the through hole. It is fixed to the holder by an interposed joining member.

  Further, a protrusion is provided in a region of the inner surface of the sleeve where the slits are opposed to each other with the through hole interposed therebetween.

  Further, the sleeve is characterized in that ceramic is a main component, and the joining member is formed of a resin material containing a filler made of ceramic which is the main component of the sleeve.

  Further, when an elastic member is interposed in the gap in an area where the joining member does not exist, when the longitudinal elastic modulus of the joining member is E1 and the longitudinal elastic modulus of the elastic member is E2, E1> E2 It is a relationship.

  Further, the elastic member includes a resin.

  Further, an eccentricity measuring device for measuring the amount of eccentricity of the inner hole of the ferrule, the ferrule holder described above, a light source for introducing light into the inner hole of the ferrule held by the ferrule holder, A photoelectric conversion element having a light receiving portion for transmitting the light in the inner hole and receiving light derived from the inner hole of the ferrule, and an image processing device for imaging an electric signal from the photoelectric conversion element An eccentricity measuring device.

  An eccentricity measuring device for measuring the amount of eccentricity of the core of the optical fiber, wherein light is applied to the ferrule holder described above and the optical fiber inserted into the inner hole of the ferrule held by the ferrule holder. A light source for introduction, a photoelectric conversion element having a light receiving portion for transmitting the optical fiber and receiving light derived from the optical fiber, and an electric signal from the photoelectric conversion element for imaging And an image processing device.

  Further, from the data of the inner hole shape of the ferrule or the core shape of the optical fiber of the image obtained by the image processing device, an inscribed circle with respect to the contour of the ferrule inner hole shape or the optical fiber core shape is calculated by the arithmetic processing device. , Draw one of the circumscribed circle, find its center position, calculate the maximum deviation amount of the center position obtained when rotating the ferrule, and display the half value of the maximum deviation amount as the core eccentricity amount It is characterized by that.

  Further, from the image obtained by the image processing device obtained when the ferrule is rotated, the maximum deviation amount of the ferrule inner hole shape or the optical fiber core shape circle is calculated by the arithmetic processing device, and the maximum The half value of the deviation amount is displayed as the core eccentricity amount.

  As described above, according to the present invention, a sleeve having a slit in the longitudinal direction and having a through-hole for holding a ferrule into which an optical fiber is inserted into an inner hole, and a holder for arranging the sleeve therein The sleeve is arranged by providing a gap between the sleeve and the holder, and a joining member interposed in the gap in a region where the slit is opposed to the through hole. By fixing to the holder, excessive deformation of the sleeve can be suppressed and the ferrule can be gripped. As a result, even when the eccentricity is repeatedly measured, it is possible to obtain a stable measurement value with little fluctuation.

  Embodiments of the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the ferrule holder 10 of the present invention includes a sleeve 1, a holder 2 in which the sleeve 1 is disposed, and a joining member 3.

  A sleeve 1 (hereinafter referred to as a split sleeve 1) has a slit 1b in the longitudinal direction and a through hole 1a for holding a ferrule 5 into which an optical fiber is inserted into an inner hole. The inner diameter of the through hole 1a is set to a diameter that is several microns smaller than the ferrule 5 to be inserted. On the other hand, the slit 1b has a spring force acting on the ferrule 5 inserted into the sleeve 1, and the ferrule 5 has a function of gripping.

As the material of the sleeve 1, for example, other metals such as phosphor bronze, beryllium copper, brass and stainless steel, plastics such as epoxy and liquid crystal polymer, and ceramics such as alumina and zirconia can be used. Among these, it is particularly preferable to form with zirconia ceramics. When zirconia ceramics is used for the sleeve 1, specifically, ZrO ₂ is the main component, and at least one of Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _{3 and the} like is contained as a stabilizer, and is square. It is preferable to use partially stabilized zirconia ceramics mainly composed of crystal crystals, and such partially stabilized zirconia ceramics are advantageous because they have excellent wear resistance and moderate elastic deformation.

  As a processing method of the sleeve 1, for example, when it is formed from zirconia ceramics, a cylindrical molded body that becomes a sleeve is obtained in advance by a predetermined molding method such as injection molding, press molding, extrusion molding, etc. Baking at ˜1500 ° C. and grinding or polishing to a predetermined dimension. Note that a predetermined shape may be formed in advance on the formed body by cutting or the like, and then fired.

  In the case of plastics, any shape can be easily manufactured by devising a mold. Furthermore, when it is made of metal, a rod-like or pipe-like material can be manufactured by machining such as cutting, grinding, polishing, and pressing.

  The holder 2 has a function of protecting the sleeve 1 while forming an inner hole for arranging the sleeve 1 therein. The holder 2 is made of a material that can be welded to stainless steel, copper, iron, nickel, and the like and is relatively easy to process because the holder 2 is joined to an eccentricity measuring apparatus body described later. Stainless steel is mainly used in consideration of corrosion resistance and weldability.

  Further, it is desirable to provide a protrusion 2b in the longitudinal direction in the inner hole of the holder 2 in order to adhere and fix the outer peripheral portion of the region 1c facing the through hole 1a of the sleeve 1. Furthermore, it is preferable that the inner hole of the holder 5 has an arithmetic average roughness (Ra) of the inner peripheral surface of 0.1 μm or more in order to improve the adhesive force between the joining member 3 and the elastic member 4 described later.

  The joining member 3 is interposed between the sleeve 1 and the holder 2 in a region 1c where the slit 1b is opposed across the through hole 1a. Even if a ferrule 5 is inserted into the sleeve 1 and a lateral load or the like is applied thereto, , And has a function of suppressing excessive deformation generated in the sleeve 1. As the material of the joining member 3, it is desirable to use a high-hardness adhesive, for example, a thermosetting resin such as an epoxy resin, a phenol resin, a resorcin resin, a urea resin, a melamine resin, an alkyd resin, or ultraviolet irradiation. Although a UV curable resin that cures can be used, it is most desirable to use an epoxy resin in consideration of environmental resistance and the like. Such a joining member 3 can be produced, for example, by applying the above-described adhesive to the region 1c of the sleeve 1 and curing the adhesive by heating or ultraviolet irradiation. In manufacturing the joining member 3, an adhesive may be applied to the holder 5 facing the region 1c of the sleeve 1 through a gap and cured.

  On the other hand, the ferrule 5 held by the ferrule holder of the present invention has, for example, a cylindrical shape, and is bonded and fixed to the optical fiber 6 through an internal through hole as a protective member for connecting the optical fiber. It is what is used. In order to reduce the connection loss with the plug ferrule, the tip portion that contacts the ferrule (plug ferrule) having another optical fiber in order for the ferrule 5 having the optical fiber to be optically connected is a curved surface having a curvature radius of about 5 to 30 mm. It is processed into a shape.

As the material of the ferrule 5, other metals such as a copper alloy, a nickel alloy, stainless steel, an epoxy, a plastic such as a liquid crystal polymer, a ceramic, or the like can be used. Among these, it is particularly preferable to form with zirconia ceramics. Specifically, partial stabilization mainly comprising tetragonal crystals, containing ZrO ₂ as a main component, at least one of Y ₂ O ₃ , CaO, MgO, CeO ₂ , Dy ₂ O _{3 and the} like as a stabilizer. Zirconia ceramics are preferably used, and such partially stabilized zirconia ceramics are advantageous because they have excellent wear resistance and moderate elastic deformation.

  Next, another embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 2A, in the present invention, it is preferable that a protrusion 1d is provided in a region 1c where the slit 1b is opposed to the inner surface of the sleeve 1 with the through hole 1a interposed therebetween. This is because the region 1c where the slit 1b faces across the through-hole 1a is the portion where the bending stress of the sleeve 1 is the largest, and the provision of the protruding portion 1d prevents the sleeve 1 from being bent and broken. Because it can.

  Further, if the projecting portions 1d are provided at equal intervals in the inner hole of the sleeve 1, the force for gripping the ferrule 5 acts uniformly on the ferrule 5, so that even when the ferrule 5 is rotated, a stable eccentricity measurement value is obtained. Is desirable in terms of obtaining At this time, it is desirable that the projecting portions 1d are provided at seven positions at intervals of 45 degrees with respect to the central axis of the inner hole of the sleeve 1 in terms of improving the stability of repeated measurement of the eccentric amount of the ferrule 5.

  Next, FIG. 2B shows a method in which the sleeve 1 is fixed only by the joining member 3 without providing the protrusion 2 b in the inner hole of the holder 2. Even in such a form, there is an effect of gripping the ferrule 5 and suppressing breakage due to excessive deformation of the sleeve 1, but if the sleeve 1 is made of ceramics, the bonding member 3 is made of the ceramics. It is desirable to form by the resin material containing the filler which consists of.

  The resin material may be, for example, a thermosetting resin such as an epoxy resin, a phenol resin, a resorcin resin, a urea resin, a melamine resin, an alkyd resin, or a UV curable resin that is cured by ultraviolet irradiation. It is most desirable to use the material in consideration of environmental resistance and the like. Moreover, as a method of producing the joining member 3 with a resin material containing such a filler, a resin material uniformly containing a filler having an average particle diameter of 0.005 to 5 μm, preferably 0.01 to 1 μm is used. It is prepared, and after adding a curing agent as necessary, it is applied to a predetermined position and cured by heating or ultraviolet irradiation.

  Next, as still another embodiment of the present invention, as shown in FIG. 3, an elastic member 4 may be interposed in a region where the joining member 3 does not exist. At this time, when the longitudinal elastic modulus of the joining member 3 is E1 and the longitudinal elastic modulus of the elastic member 4 is E2, it is preferable that E1> E2.

  That is, the joining member 3 is made of a material that is not easily elastically deformed as compared with the elastic member 4, while the elastic member 4 is made of a material that can be elastically deformed relatively easily, so that the joining member 3 is made of the slit 1 b of the sleeve 1. However, the sleeve 1 is firmly fixed in the region 1c facing the through-hole 1a so as to suppress breakage due to excessive deformation of the sleeve 1, and the elastic member 4 is opposed to the sleeve 1 without obstructing free deformation. The sleeve 1 has a function of deforming the sleeve 1 substantially uniformly with reference to the region 1c to be used. The elastic member 4 is mainly made of resin. For example, if the bonding member 3 is made of epoxy resin, the elastic member 4 is made of silicon-based resin.

The longitudinal elastic modulus can be expressed by Young's modulus. Young's modulus is considered to follow Hooke's law when plastics are microdeformed, and is defined as Young's modulus = tensile stress ÷ tensile strain. Therefore, Young's modulus = force per unit area ÷ elongation per unit length = F / A ÷ ΔL / L0 (where F: tensile force, A: cross-sectional area, ΔL: elongation due to force F, L0: original length)
This longitudinal elastic modulus test method can be performed by using, for example, a Tensilon universal testing machine UCT-5T (manufactured by Orientec Co., Ltd.), before measuring the cross-sectional area (A) and the elongation (L0) due to force F. If the test piece is measured in advance and the tensile load and the length are recorded in the chart in the tensile test, the Young's modulus can be obtained from the initial linear portion by the above equation.
Next, the manufacturing method of the ferrule holder of this invention is demonstrated.

  First, for example, the sleeve 1 is formed by extruding a zirconia raw material and then fired to produce a cylindrical zirconia sintered body, and the slit 1b is formed by grinding in the longitudinal direction of the zirconia sintered body. It is obtained by forming. On the other hand, the holder 2 is obtained, for example, by cutting stainless steel into a cylindrical shape provided with protrusions 2b in the longitudinal direction of the inner peripheral surface. Next, an epoxy adhesive (EPOTEK-353ND manufactured by Epoxytechnology) is applied to the protrusion 2b of the holder 2. Then, the sleeve 1 is arranged so that the adhesive applied to the protruding shape 2b comes into contact with a region 1c facing the through hole of the sleeve 1 of the slit 1b. Finally, an adhesive made of an epoxy resin is cured at about 85 ° C. for 2 hours to produce a ferrule holder.

  Next, a method for fixing the ferrule holder 10 of the present invention to an eccentricity measuring device for measuring the eccentricity of the inner hole of the ferrule 5 or the core of the optical fiber will be described.

  As shown in FIG. 4, the ferrule holder 10 is fixed to the fixture 7 for holding the outer peripheral portion of the holder 2 by press-fitting, bonding, soldering, welding or the like. Furthermore, the fixture 7 is fixed to a side plate 8 of an eccentricity measuring device (not shown) using screws 9.

  FIG. 4 is an example for fixing the ferrule holder 10 of the present invention, and may be a method of fixing to the side plate 8 by press-fitting, bonding, soldering, welding, or the like. However, since only the ferrule holding part 10 of the eccentric measuring instrument already in operation may be exchanged, a method of fixing with the screw 9 as shown in FIG.

  Further, the ferrule holder of the present invention is not limited to being used for an eccentricity measuring device, but can also be used for an optical receptacle or an optical module.

  Next, an eccentricity measuring apparatus using the ferrule holder of the present invention will be described.

  FIG. 5A is a cross-sectional view of the eccentricity measuring device 100 for measuring the eccentricity of the inner hole of the ferrule 5 in a state where the optical fiber is not fixed. The eccentricity measuring device 100 includes a ferrule holder 10, a light source 11, a photoelectric conversion element 12, and an image processing device 13.

  The light source 11 has a function of introducing light into the inner hole of the ferrule 5 held by the ferrule holder 10. For example, TechnoLight (model name: KR-100RSV) manufactured by Kenko can be used as the light source 11, and a lightwave manufactured by Kenko made of an optical fiber having a lens provided at the tip of the light source 11, for example. By connecting a guide (model number 201 type) and outputting predetermined light from the light source 11, light can be efficiently introduced into the inner hole of the ferrule.

  The photoelectric conversion element 12 has a light receiving portion 12a for transmitting light in the inner hole of the ferrule 5 and receiving light derived from the inner hole, and converts an optical signal received by the light receiving portion 12a into an electric signal. It has the function to do. For example, a CCD camera can be used as the photoelectric conversion element 12, and a lens may be provided between the ferrule 5 and the photoelectric conversion element 12 in order to improve the light collection efficiency with respect to the light receiving portion of the CCD camera.

  The image processing device 13 has a function of imaging the electrical signal transmitted from the photoelectric conversion element 12. Then, the amount of eccentricity of the ferrule is derived from this imaged information.

  Next, a method for measuring the amount of eccentricity of the inner hole in the ferrule 5 using the eccentricity measuring apparatus 100 of the present invention will be described.

  First, the ferrule 5 for measurement is inserted into the inner hole of the sleeve 1 of the ferrule holder 10. Next, light is output from the light source 11, and the light emitted from the light source 11 is incident from the rear end of the ferrule 5 and is emitted from the front end through the inner hole of the ferrule 5. The shape of the light is sensed by the light receiving unit 12a, and after the optical signal is converted into an electrical signal by the photoelectric conversion element 12, the shape of the inner hole of the ferrule 5 is recognized by the image processing apparatus. In this calculation, there are a method for confirming the center position of the inner hole and a method for confirming the contour of the inner hole. The center position of the inner hole is drawn by inscribed and circumscribed circles from the contour of the inner hole. The center position of is defined as the center.

  Next, the ferrule 5 is pulled out from the sleeve 1 of the ferrule holder 10, the ferrule 5 is rotated around the axis of the ferrule 5 by a predetermined angle, and the ferrule 5 is inserted into the sleeve 1 again to center the inner hole of the ferrule 5. Check the position or outline. The predetermined angle is 90 ° rotation with respect to the axis of the ferrule 5 if the measurement is performed four times per rotation, and is measured with respect to the axis of the ferrule 5 if the measurement is performed eight times per rotation. Rotation of 45 °. If the measurement is four times per rotation, the measurement is finished at the fourth measurement, a virtual circle is drawn for each center position, the diameter becomes concentricity, and the radius becomes the eccentric amount.

  FIG. 5B is a cross-sectional view of the eccentricity measuring apparatus 101 for measuring the eccentricity of the core of the optical fiber fixed in the inner hole of the ferrule 5. The eccentricity measuring device 101 includes a ferrule holder 10, a light source 11, a photoelectric conversion element 12, and an image processing device 13. The ferrule holder 10, the light source 11, the photoelectric conversion element 12, and the image processing device 13 may be the same as the eccentricity measuring device 100 described above.

  Next, a method for measuring the amount of core eccentricity in the optical fiber 6 using the eccentricity measuring apparatus 101 of the present invention will be described.

  First, the ferrule 5 with the optical fiber 6 to be measured is inserted into the inner hole of the sleeve 1 of the ferrule holder 10. The light emitted from the light source 11 is transmitted through the optical fiber 6 and emitted from the tip of the ferrule 5. The shape of the light is sensed by the light receiving unit 12a, and after the optical signal is converted into an electric signal by the photoelectric conversion element 12, the shape of the core of the optical fiber 6 is recognized by the image processing device. In this calculation, there are a method for confirming the center position of the core and a method for confirming the contour of the core. The center position of the core draws an inscribed circle and circumscribed circle from the contour of the core, and the center position of the circle is determined. There are methods of centering, centering the point with the highest light intensity of the core, or centering the center of gravity of the core shape.

  Next, the ferrule 5 is pulled out from the sleeve 1 of the ferrule holder 10, the ferrule 5 is rotated about the axis of the ferrule 5 by a predetermined angle, and the ferrule 5 is inserted into the sleeve 1 again to remove the inner hole of the ferrule 5. Check the center position or outline. The predetermined angle is 90 ° rotation with respect to the axis of the ferrule 5 if the measurement is performed four times per rotation, and is measured with respect to the axis of the ferrule 5 if the measurement is performed eight times per rotation. Rotation of 45 °. If the measurement is four times per rotation, the fourth measurement is finished, a virtual circle is drawn for each center position, the diameter becomes concentricity, and the radius becomes the eccentricity.

  Next, an arithmetic processing method of the eccentricity measuring apparatus using the ferrule holder of the present invention will be described.

  FIG. 9A shows a flowchart of the calculation processing method.

  From the image of the ferrule inner hole shape 51 or optical fiber core shape 52 of the image obtained by the image processing device, the arithmetic processing device inscribes the ferrule inner hole shape 51 or the optical fiber core shape 52 from the contour. A circle 53 or a circumscribed circle 54 is drawn to determine its center position 56, and a maximum shift amount 58 of the center position 56 obtained when the ferrule is rotated based on the outer diameter 57 is calculated. The half value of the deviation amount 58 is displayed as the core eccentricity amount 59.

  By performing such image processing and calculation processing, it is possible to accurately measure the amount of core eccentricity even with the inner hole shape 51 of the distorted ferrule or the core shape 52 of the optical fiber.

  FIGS. 9B and 9C are diagrams for explaining the inscribed circle 53, the circumscribed circle 54, and the center position 56 of the present invention. The inner shape 51 of the distorted ferrule or the core shape 52 of the optical fiber is shown in FIGS. From the above, the inscribed circle 53, the circumscribed circle 54, and the center position 56 can be obtained.

  In FIG. 9D, from the maximum shift amount 58 of the center position 56 obtained when the ferrule is rotated with reference to the outer diameter 57, the half value of the maximum shift amount 58 is set as the core eccentricity 59.

  Thus, since the inner hole shape 51 of the ferrule or the core shape 52 of the optical fiber is actually a distorted circle, the amount of core eccentricity can be measured by using the arithmetic processing method of the present invention.

  Next, FIG. 10A shows a flowchart of another arithmetic processing method.

When the circle of the ferrule inner hole shape 51 or the optical fiber core shape 52 is rotated with reference to the outer diameter 57 from the image obtained by the image processing device obtained when the ferrule is rotated. The maximum deviation amount 58 is calculated, and the half value of the maximum deviation amount 58 is displayed as the core eccentricity 59. By performing such image processing and calculation processing, the inner hole shape 51 of the distorted ferrule or Even with the core shape 52 of the optical fiber, it is possible to accurately measure the amount of core eccentricity.

  In FIG. 10B, from the maximum shift amount 58 of the center position 56 obtained when the ferrule is rotated with reference to the outer diameter 57, the half value of the maximum shift amount 58 is used as the core eccentricity 59.

  Thus, since the inner hole shape 51 of the ferrule or the core shape 52 of the optical fiber is actually a distorted circle, the amount of core eccentricity can be measured by using the arithmetic processing method of the present invention.

  While the embodiments of the present invention have been described above, various modifications can be made without departing from the scope of the present invention.

  For example, in the above-described configuration, the SC type optical connector plug is exemplified, but the present invention is not limited to the optical connector plug having a single mode (SM) optical fiber, for example, MU type, LC type, FC type or An ST-type optical connector plug may be used.

  Below, the ferrule holder of the present invention was mounted on an eccentricity measuring device for measuring the eccentricity of the ferrule inner hole, and the eccentricity of the inner hole of the ferrule was measured and the variation of the measured value was verified.

  First, a method for manufacturing a ferrule holder will be described. In the sleeve 1, a cylindrical body made of zirconia is ground to form a slit 1b extending in the longitudinal direction, and has an inner diameter φ2.493 mm, a length 6 mm, and an outer diameter φ3.4 mm. The holder 2 has a cylindrical cylindrical shape made of stainless steel, has an inner diameter of 3.6 mm, an outer diameter of φ4.64 mm, and is long enough to accommodate the sleeve 1. In addition, the bonding member 3 is bonded and cured by using epoxy resin (model number: Epotek353ND) under the condition of 85 ° C. for 2 hours with the region 1c facing the through hole of the sleeve 1 and the protrusion 2b of the holder 2 facing each other. Thus, a ferrule holder 10 was produced.

  Then, as shown in FIG. 4, the ferrule holder 10 obtained above was press-fitted and fixed to the fixture 7, and then the fixture 7 was fixed to the side plate 8 of the eccentricity measuring instrument with screws 9.

  The ferrule used for the measurement of the eccentric amount is a cylindrical body made of zirconia ceramics, and 15 ferrules having an outer diameter of 2.500 mm, a length of 10.5 mm, and an inner diameter of 0.1255 to 0.1260 mm were prepared.

  Next, measurement of the amount of eccentricity of the inner hole of the ferrule will be described. First, the ferrule 5 for measurement is inserted into the inner hole of the sleeve 1 of the ferrule holder 10. Next, the light emitted from the light source 11 (TechnoLight model name KR-100RSV manufactured by Kenko) enters from the rear end of the ferrule 5, exits from the front end through the inner hole of the ferrule 5, and the shape of the light is changed. After sensing by the light receiving unit 12a and converting the optical signal into an electric signal by the photoelectric conversion element 12, the shape of the inner hole of the ferrule 5 was recognized by the image processing apparatus. Here, in the calculation, the center position of the inscribed circle was defined as the center from the contour of the inner hole by the method of looking at the center position of the inner hole.

  Next, the ferrule was pulled out from the sleeve 1 of the ferrule holder 10 and rotated about the axis of the ferrule 5 at a predetermined angle, and inserted again into the sleeve 1 to confirm the center position or contour of the ferrule inner hole. In this example, the rotation was 90 ° with respect to the axis of the ferrule 5 and the measurement was performed four times per rotation. After completing these four measurements, a virtual circle was drawn for each center position, and the radius was defined as the amount of eccentricity.

  Further, as a comparative example, an eccentricity measuring apparatus (Comparative Example 1) including a conventional ferrule holder 30 using a V-groove substrate made of zirconia having a V-groove angle of 90 degrees shown in FIG. 7 and FIG. The eccentricity of the ferrule inner hole was measured using an eccentricity measuring device (Comparative Example 2) provided with a conventional ferrule holder 30 in which no joining member was interposed between the sleeve and the holder shown. Note that the light source, photoelectric conversion element, and image processing apparatus used in Comparative Example 1 and the sleeve, holder, light source, photoelectric conversion element, and image processing apparatus used in Comparative Example 2 are the same as the examples of the present invention. Similar ones were used. Further, in the measurement of the amount of eccentricity of the ferrule, as in Example 1, it was rotated 90 ° with respect to the axial center of the ferrule 5 and measured four times per rotation, and the amount of eccentricity was measured.

For measuring the amount of eccentricity of the ferrule, five samples from sample 1 to sample 5 are assigned to each measuring device, and the amount of eccentricity of the inner hole of the ferrule is measured for each 10 data, and the minimum and maximum of the measured values are measured. The values are shown in Table 1.

  As shown in Table 1, in Comparative Examples 1 and 2, a measurement variation of 0.07 μm (difference between the maximum value and the minimum value of the measurement values) occurred.

  On the other hand, in the present invention, since the variation in the amount of eccentricity was as small as 0.02 μm, a ferrule holder capable of stably measuring the amount of eccentricity could be provided.

  Next, the core eccentricity was measured from the maximum deviation amount at the center of the circle, which is the calculation processing method of the present invention, and the connection loss value was measured.

  The ferrule 5 used for measuring the amount of eccentricity is a cylindrical body made of zirconia ceramics. Ten ferrules 5 having an outer diameter of 2.500 mm, a length of 10.5 mm, and an inner diameter of 0.1255 to 0.1260 mm are prepared. did. Then, an optical fiber was bonded and fixed to the ferrule 5, and a connector housing or the like was assembled on the outer peripheral portion to produce an optical connector.

  Next, the measurement of the eccentricity of the core of the optical fiber will be described. First, the ferrule 5 for measurement is inserted into the inner hole of the sleeve 1 of the ferrule holder 10. Next, light incident on the optical fiber from the light source 11 is emitted from the tip through the optical fiber in the ferrule 5, the shape of the light is detected by the light receiving unit 12 a, and the photoelectric signal is converted into an electric signal by the photoelectric conversion element 12. After conversion to a signal, the shape of the core was recognized by the image processing apparatus. Here, an inscribed circle was drawn from the outline of the core shape, and the center position was the center.

  Next, the ferrule 5 was pulled out from the sleeve 1 of the ferrule holder 10, rotated around the axis of the ferrule 5 at a predetermined angle, inserted again into the sleeve 1, and the center position or outline of the inner hole of the ferrule 5 was confirmed. In this example, the rotation was 90 ° with respect to the axis of the ferrule 5 and the measurement was performed four times per rotation. After completing these four measurements, a virtual circle was drawn for each center position, and the radius was defined as the amount of eccentricity.

  Next, the connection loss was measured using a reference plug with a core eccentricity of 0.05 μm and a reference adapter with a connection loss of 0.01 dB.

  The eccentricity of the core of 10 samples is 0.13, 0.22, 0.32, 0.40, 0.53, 0.61, 0.73, 0.82, 0.93, 1.03 μm FIG. 11 shows the result of plotting the splice loss value against the plot.

  From this result, since the connection loss is proportional to the square of the amount of core eccentricity, the points plotted in a quadratic curve are arranged, so it can be said that the arithmetic processing method of the present invention is effective.

  In addition, the core eccentricity was measured from the maximum deviation of the circle, which is another calculation processing method of the present invention, and the connection loss value was measured.

  The ferrule 5 used for measuring the amount of eccentricity is a cylindrical body made of zirconia ceramics, and 10 ferrules having an outer diameter of 2.500 mm, a length of 10.5 mm, and an inner diameter of 0.1255 to 0.1260 mm were prepared. . Then, an optical fiber was bonded and fixed to the ferrule 5, and a connector housing or the like was assembled on the outer peripheral portion to produce an optical connector.

  Next, the measurement of the eccentricity of the core of the optical fiber will be described. First, the ferrule 5 for measurement is inserted into the inner hole of the sleeve 1 of the ferrule holder 10. Next, light incident on the optical fiber from the light source 11 is emitted from the tip through the optical fiber in the ferrule 5, the shape of the light is detected by the light receiving unit 12 a, and the photoelectric signal is converted into an electric signal by the photoelectric conversion element 12. After conversion to a signal, the shape of the core was recognized by the image processing apparatus.

  Next, the ferrule 5 was pulled out from the sleeve 1 of the ferrule holder 10, rotated around the axis of the ferrule 5 at a predetermined angle, inserted again into the sleeve 1, and the center position or outline of the inner hole of the ferrule 5 was confirmed. In this example, the rotation was 90 ° with respect to the axis of the ferrule 5 and the measurement was performed four times per rotation. After completing the four measurements, the amount of deviation of each core-shaped circle edge was measured, and the half value thereof was defined as the amount of eccentricity.

  Next, the connection loss was measured using a reference plug with a core eccentricity of 0.05 μm and a reference adapter with a connection loss of 0.01 dB.

  The eccentricity of the core of 10 samples is 0.18, 0.22, 0.26, 0.36, 0.51, 0.69, 0.88, 1.03, 1.33, 1.53 μm FIG. 12 shows the result of plotting the splice loss value against the plot.

  From this result, since the connection loss is proportional to the square of the amount of core eccentricity, the points plotted in a quadratic curve are arranged, so it can be said that the arithmetic processing method of the present invention is effective.

  As a comparative example, a ferrule into which an optical fiber was inserted was set on the V groove and rotated, and the amount of deviation was measured with the peak of light emitted from the optical fiber as the core center position.

  On the light receiving side, a microscope is connected to a video camera and the light intensity is measured on a monitor.

  As a result, as shown in FIG. 13, a positive correlation diagram with variation in connection loss with respect to the amount of eccentricity is obtained, so that it can be seen that variations occur in the conventional concentricity measurement.

It is a perspective view which shows the ferrule holder of this invention. (A) And (b) is a side view which shows the ferrule holder of this invention. It is a side view which shows the ferrule holder of this invention. It is sectional drawing which shows the state by which the ferrule holder of this invention was fixed. (A) And (b) is sectional drawing which shows the eccentricity measuring apparatus of this invention, respectively. (A) is a perspective view which shows a general optical connector plug, (b) is a side view of the optical fiber mounted in an optical connector plug. It is a side view which shows the conventional ferrule holder. It is sectional drawing which shows the conventional ferrule holder. (A) is a flowchart which shows the arithmetic processing method, (b), (c) is a figure which shows the method of drawing a circle, (d) is a figure explaining how to obtain | require core eccentricity. (A) is a flowchart which shows the arithmetic processing method, (b) is a figure explaining how to obtain | require the amount of core eccentricity. It is a graph which shows the Example of this invention. It is a graph which shows the other Example of this invention. It is a graph which shows the comparative example of this invention.

Explanation of symbols

1: Sleeve 1a: Through-hole 1b: Slit 1c: Region 1d facing the slit across the through-hole 1d: Ribbed portion 2: Holder 2b
3: Joining member 4: Elastic member 5: Ferrule 6: Optical fiber 7: Fixture 8: Side plate 9: Screw 10: Ferrule holder 11: Light source 12: Photoelectric conversion element 12a: Light receiving unit 13: Image processing device 20: Light Connector plug 21: Ferrule 21a: Optical fiber insertion hole (inner hole of ferrule)
21b: taper portion 22: optical fiber 22a: core 22b: clad 30: ferrule holder 31: V groove 32: pressing member 33: ferrule 34: optical fiber 40: ferrule holder 41: split sleeve 42: holder 43: stopper 44 : Ferrule 51: Ferrule inner hole shape 52: Optical fiber core shape 53: Inscribed circle 54: circumscribed circle 56: Center position 57: Outer diameter 58: Maximum deviation 59: Core eccentricity 100, 101: Eccentricity measurement apparatus

Claims (9)

A sleeve having a slit in the longitudinal direction and a through hole for holding a ferrule into which an optical fiber is inserted into the inner hole;
A ferrule holder comprising a holder for disposing the sleeve therein,
The sleeve is disposed with a gap between the sleeve and the slit is fixed to the holder by a joining member interposed in the gap in a region where the slit is opposed to the through hole. A ferrule holder.   2. The ferrule holder according to claim 1, wherein a ridge portion is provided in a region of the inner surface of the sleeve where the slits face each other across the through hole.   3. The ferrule holding device according to claim 1, wherein the sleeve is made of a ceramic material as a main component, and the joining member is made of a resin material containing a filler made of a ceramic material as the main component of the sleeve. Ingredients.   Within the gap, an elastic member is interposed in a region where the joining member does not exist, and when the longitudinal elastic modulus of the joining member is E1 and the longitudinal elastic modulus of the elastic member is E2, the relationship is E1> E2. The ferrule holder according to any one of claims 1 to 3, wherein the ferrule holder is provided.   The ferrule holder according to claim 4, wherein the elastic member includes a resin. An eccentricity measuring device for measuring the eccentricity of an inner hole of a ferrule,
The ferrule holder according to any one of claims 1 to 5,
A light source for introducing light into the inner hole of the ferrule held by the ferrule holder;
A photoelectric conversion element having a light receiving portion for transmitting light in the inner hole and receiving light derived from the inner hole of the ferrule;
An eccentricity measuring apparatus comprising: an image processing apparatus that images an electrical signal from the photoelectric conversion element. An eccentricity measuring device for measuring the eccentricity of an optical fiber core,
The ferrule holder according to any one of claims 1 to 5,
A light source for introducing light into the optical fiber inserted into the inner hole of the ferrule held by the ferrule holder;
A photoelectric conversion element having a light receiving portion for transmitting the optical fiber and receiving light derived from the optical fiber;
An eccentricity measuring device comprising: an image processing device for imaging an electric signal from the photoelectric conversion element.   From the data of the ferrule inner hole shape or the optical fiber core shape of the image obtained by the image processing device, an inscribed circle and a circumscribed circle with respect to the ferrule inner hole shape or the optical fiber core shape contour in the arithmetic processing device Draw one of the circles, find its center position, calculate the maximum deviation of the center position obtained when the ferrule is rotated with reference to the outer diameter, and display the half value of the maximum deviation as the core eccentricity The eccentricity measuring apparatus according to claim 6 or 7, characterized in that:   From the image obtained by the image processing device obtained when the ferrule is rotated on the basis of the outer diameter, the maximum deviation amount of the edge of the ferrule inner hole shape or the core shape of the optical fiber is calculated by the arithmetic processing device, The eccentricity measuring apparatus according to claim 6 or 7, wherein a half value of the maximum deviation amount is displayed as a core eccentricity amount.

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