JP2005173251A - Fixing structure of optical fiber, and optical connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure of an optical fiber and an optical connector which permit to fix an optical fiber to a ferrule easily, exactly, and also at a low cost, and do not cause an increase in transmission loss without blemishing the optical fiber. <P>SOLUTION: In a fixing structure of the optical fiber 5 for fixing the optical fiber to the ferrule 10, the ferrule 10 is constituted of an almost ring-like optical fiber aligning part 14 with an optical fiber threading hole 16 of a true circle, an optical fiber press-fitting part 18, and an almost ring-like ferrule brim part 20 by folding a part of a punched plate 12 formed by punching a metal plate made of a brass material or the like excellent in press workability such as punching and folding, and the optical fiber 5 is threaded through the optical fiber threading hole 16 of the optical fiber aligning part 14 and engaged therein, and the optical fiber 5 is also clamped and press-fitted to the ferrule 10 by the optical fiber press-fitting part 18 for fixation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical fiber fixing structure and an optical connector for fixing an optical fiber to a ferrule.

  2. Description of the Related Art In recent years, with the speeding up of personal computers and LANs (local area networks) and the diversification of services, the speed of signal transmission has been increased, and communication using optical fibers has become popular. In addition, the computerization of vehicles such as automobiles has progressed dramatically, and the processing amount of communication information such as data, images, and sounds in the vehicle is increasing.

  As mentioned above, as the speed of signal transmission increases and the amount of communication information processing increases, the effects of noise in communications increase, so optical fibers such as plastic optical fibers that can reduce the effects of noise are used for signal transmission. It is starting to be used on the road.

  This type of optical fiber is generally provided with a coating such as nylon. As a form of coating, a multilayer coating is provided in which a primary coating such as nylon is provided on the outer peripheral side of the optical fiber, and a secondary coating (jacket) such as nylon is provided on the outer peripheral side of the primary coating. There are many things. When this optical fiber is used as a high-speed signal transmission line, for example, the coating on the connection end face side is removed and the optical fiber is exposed, or the secondary coating is removed and the primary coating is exposed. In this state, the exposed portion and the covering portion are inserted and fixed to a ferrule or the like. An appropriate optical fiber insertion hole is formed in the ferrule or the like.

  As an example of the fixing structure of the optical fiber, an optical fiber is inserted into an optical fiber insertion hole of a metal ferrule made of a metal sleeve by extrusion, cutting or the like, or a resin molding process, and the ferrule is made of an adhesive such as an epoxy resin. An optical fiber is known that is fixed (see Patent Document 1).

  Further, there has been proposed an optical fiber fixed to the ferrule by crimping the ferrule into a hexagonal shape with the optical fiber inserted into the optical fiber insertion hole of the ferrule made of the metal sleeve ( Patent Document 1).

  Furthermore, in a state where the optical fiber is inserted into the optical fiber insertion hole of the transparent resin ferrule, laser light is irradiated from the outside of the ferrule, and the resin composing the ferrule and the coating resin of the optical fiber are welded. There has also been proposed an optical fiber that is fixed to an optical fiber (see Patent Document 1).

  Further, as shown in FIG. 6, an optical fiber fixture 1 in which a U-shaped slot 4 opening downward is formed in a leg portion 3 provided in front of and behind a U-shaped metal member 2. There has also been proposed one in which the optical fiber 5 is fixed to the fixture 1 by press-fitting the optical fiber 5 (see Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 2002-107573 (paragraph numbers 0005 to 0010 in FIG. 6 in the Detailed Description of the Invention, FIG. 6) Japanese Utility Model Publication No. 05-59412 (claims for registration of utility model, FIGS. 1 and 2)

  However, in the case where the optical fiber is fixed to the ferrule using an adhesive such as an epoxy resin as described above, it is troublesome to handle the adhesive, and depending on the adhesive used, unevenness (variation) tends to occur. In some cases, the optical fiber cannot be reliably and stably fixed. Further, when using a ferrule made of a metal sleeve, there is a problem that the cost becomes high. In addition, when laser light is used to weld the ferrule resin and the optical fiber coating resin, a laser irradiation facility or the like is required, and there is a problem that equipment costs are required. Furthermore, when the optical fiber fixture 1 as shown in FIG. 6 is used, unless the dimensional accuracy of the slot 4 formed in the leg 3 provided on the metal member 2 is strictly controlled, the strands of the optical fiber 5 ( In some cases, the transmission loss may increase due to damage to the core), and when the tensile force acts on the optical fiber 5, the optical fiber 5 may come off from the optical fiber fixture 1. There is a problem that it cannot be fixed.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to fix an optical fiber to a ferrule easily, surely, and at low cost, and to prevent transmission loss without damaging the optical fiber. An object of the present invention is to provide an optical fiber fixing structure and an optical connector that do not cause an increase.

  In order to achieve the above object, the invention described in claim 1 of the present invention is an optical fiber fixing structure for fixing an optical fiber to a ferrule, wherein the ferrule is formed by punching a metal plate. An optical fiber alignment part having an optical fiber insertion hole, an optical fiber crimping part, and a ferrule collar part are provided by bending a part, and the optical fiber is inserted into the optical fiber insertion hole of the optical fiber alignment part. In addition to being fitted, the optical fiber is crimped by an optical fiber crimping portion, and the optical fiber is fixed to the ferrule.

  According to a second aspect of the present invention, there is provided an optical fiber fixing structure according to the first aspect, wherein the ferrule punches a metal plate and supports the optical fiber in the center, and extends from the head of the bottom piece. Forming a punched plate having a protruding piece in which an optical fiber insertion hole is inserted and a crimping piece and a flange piece respectively extending from both side edges of the bottom piece; An optical fiber aligning part by bending and raising the protruding piece, an optical fiber pressure-bonding part by bending and raising the crimping piece, and a ferrule collar part by bending and raising the collar piece, Inserting and fitting the optical fiber into the optical fiber insertion hole of the optical fiber aligning portion, inserting the optical fiber between the crimping pieces of the optical fiber crimping portion, and clamping and crimping the optical fiber with the crimping piece Yo And it is characterized by comprising fixing the optical fiber to the ferrule.

  According to a third aspect of the present invention, in the optical fiber fixing structure according to the first or second aspect, the optical fiber crimping portion of the ferrule is provided between the optical fiber alignment portion and the ferrule collar portion. It is characterized by that.

  According to a fourth aspect of the present invention, in the optical fiber fixing structure according to the first, second, or third aspect, the optical fiber is a plastic optical fiber.

  According to a fifth aspect of the present invention, the optical fiber fixing structure according to any one of the first to fourth aspects is accommodated in the connector housing by accommodating the ferrule in the ferrule accommodating chamber of the connector housing. The optical connector is characterized by being attached.

  According to the fixing structure of the optical fiber according to the first aspect of the present invention, since the troublesome adhesive, the expensive metal sleeve, and the expensive equipment are not used for fixing the optical fiber, the optical fiber can be easily used for the ferrule. It can be fixed reliably and at low cost. Also, since the optical fiber is crimped and fixed at the optical fiber crimping section, and the end of the optical fiber is held at the optical fiber alignment section, the optical fiber can be securely fastened without being damaged. Increase in transmission loss can be prevented.

  According to the fixing structure of the optical fiber described in claim 2 of the present invention, the number of parts is small and the structure is simple, the ferrule manufacturing efficiency is improved, and the cost of the ferrule can be further reduced. The fixing work efficiency of the optical fiber can be improved.

  According to the optical fiber fixing structure described in claim 3 of the present invention, the optical fiber crimping portion approaches the optical fiber aligning portion and the distance between the two becomes short, so that the optical fiber is more securely attached to the ferrule. It can be stably fixed, and the reliability of fixing the optical fiber can be further improved.

  According to the fixing structure of the optical fiber described in claim 4 of the present invention, the plastic optical fiber can be securely fixed. Optical communication suitable for increase can be performed accurately.

  According to the optical connector described in claim 5 of the present invention, it is possible to easily, surely and efficiently mount the optical fiber connector on the connector housing without damaging the optical fiber. can do.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. 1A and 1B show an embodiment of a fixing structure of an optical fiber according to the present invention, together with the fixing operation process. FIG. 1A is a perspective view of a state before fixing an optical fiber, and FIG. It is a perspective view of the state after fixing. FIG. 2 is a partially omitted plan view of a punched plate formed by punching a metal plate to obtain a ferrule used for fixing an optical fiber. FIG. 3 shows a ferrule obtained by bending a part of the punched plate, where (a) is a partially omitted front view and (b) is a left side view. In addition, the same code | symbol is attached | subjected to the thing of the same structure as a prior art.

  As shown in FIG. 1, the fixing structure of the optical fiber 5 of the present embodiment is an optical fiber having an optical fiber insertion hole 16 provided by bending a part of a punched plate 12 formed by punching a metal plate. In the ferrule 10 including the alignment portion 14, the optical fiber crimping portion 18, and the ferrule flange portion 20, the end portion of the optical fiber 5 is inserted into the optical fiber insertion hole 16 of the optical fiber alignment portion 14. The optical fiber 5 is crimped by the optical fiber crimping portion 18 and the optical fiber 5 is fixed to the ferrule 10 while being fitted.

  A plastic optical fiber (POF) is used as the optical fiber 5, and a primary coating 24 such as nylon is provided on the outer peripheral side of an optical fiber strand 22 composed of a core and a cladding, and a secondary coating 26 such as nylon is provided on the outer peripheral side. Provided and configured. In the optical fiber 5, the secondary coating 26 on the connection end face side is removed to expose the primary coating 24, and the connection end face is polished smoothly. The outer diameter of the optical fiber 22 is 1 mm, the outer diameter of the portion where the primary coating 24 is provided is 1.51 mm, the portion where the secondary coating 26 is provided, that is, the outer diameter of the optical fiber 5 is 2.3 mm. It is.

  The punching plate 12 constituting the ferrule 10 used for fixing the optical fiber 5 is made of metal. As shown in FIG. 2, for example, brass (C2600) having excellent press workability such as punching and bending. ) A piece of metal plate (including metal strip, tape, ribbon, etc., including the metal strip, tape, ribbon, etc.) is punched out with a press, and a bottom piece 28 for supporting the optical fiber 5 at the center, and a bottom piece 28 From the both side edges of the substantially circular center part in the longitudinal direction of the bottom piece 28, and the substantially annular projecting piece 30 in which the perfect optical fiber insertion hole 16 extended from the head of the optical fiber 5 is inserted. Rectangular crimping pieces 32, 32 extending to the side, and flanges 34 having a rectangular shape extending laterally from both side edges of the rear end of the bottom piece 28 and longer than the crimping pieces 32, 32 , 34. The punched plate 12 may be formed of a metal plate excellent in workability such as a copper alloy material, an aluminum alloy material, or a steel material other than those described above.

  As shown in FIGS. 2 and 3, the ferrule 10 is formed by bending the protruding piece 30 of the punched plate 12 vertically upward with respect to the bottom piece 28 so as to be linearly raised. The optical fiber 5 is inserted between the crimping pieces 32 and 32 by tightening the optical fibers 5 with the crimping pieces 32 and 32 by providing the portion 14 and bending the crimping pieces 32 and 32 in an arc shape substantially vertically upward. An optical fiber crimping portion 18 for crimping is provided, and the vicinity of the bottom piece 28 of the flange pieces 34, 34 is bent into a V shape to form V-shaped legs 20a, 20a, an intermediate portion is bent into an arc shape, and a gap 20b is formed between the upper ends. And a substantially annular ferrule flange 20 is provided. In the present embodiment, the optical fiber crimping portion 18 is provided between the optical fiber alignment portion 14 and the ferrule flange portion 20.

  The inner diameter of the optical fiber insertion hole 16 of the optical fiber aligning portion 14 is formed slightly larger than the outer diameter of 1.51 mm of the portion where the primary coating 24 of the optical fiber 5 is provided, and the optical fiber is inserted into the optical fiber insertion hole 16. 5 is set so that it can be inserted smoothly and fits tightly after insertion.

  When the optical fiber 5 is crimped with the crimping pieces 32, 32 by providing serrations (fine irregularities such as lines and knurls) on the inner surfaces of the crimping pieces 32, 32 of the optical fiber crimping part 18 facing each other, the optical fiber 5 And the crimping pieces 32 and 32 are increased, and the optical fiber 5 can be more reliably prevented from being detached and fixed.

  The ferrule flange 20 is configured such that the ferrule 10 inserted and accommodated in the sleeve-like ferrule accommodation chamber 40 of the connector housing 38 of the optical connector 36 as shown in FIG. It has a function of holding and holding so as not to drop out of the ferrule housing chamber 40. By providing the V-shaped legs 20a and 20a of the ferrule collar 20, the ferrule collar 20 is set to a desired outer diameter, and its center (longitudinal central axis) is the optical fiber alignment section 14 and the optical fiber. It becomes easy to match the center of the crimping part 18 concentrically (coaxially). Further, it is preferable to provide the interval 20b because the outer diameter of the ferrule flange 20 can be adjusted and the ferrule 10 can be easily held in the ferrule housing chamber 40 of the connector housing 38.

  As shown in FIG. 1A, the fixing structure of the optical fiber 5 of the present embodiment is such that the optical fiber 5 with the primary coating 24 at the end exposed is made of a ferrule flange 20 and an optical fiber crimping portion 18 of the ferrule 10. The end portion of the optical fiber 5 is inserted into the optical fiber insertion hole 16 of the optical fiber alignment portion 14 and fitted. Next, as shown in FIG. 1 (b), the crimping pieces 32, 32 of the optical fiber crimping portion 18 are pressed inward, and the optical fiber 5 is clamped and crimped by the crimping pieces 32, 32. The fiber 5 is fixed.

  By the way, when the optical fiber 5 is a plastic optical fiber, the allowable connection loss is set to about 2 dB. When the outer diameter of the optical fiber 22 is 1 mm, the maximum allowable axis deviation of the optical fiber 5 is 0.25 mm. For this reason, the dimensional accuracy required for the ferrule 10 is an outer diameter tolerance of +/− 0.05 mm, an inner diameter tolerance of +/− 0.05 mm, and an allowable eccentricity of the outer diameter and inner diameter of about 0.03 mm. This is because when the inner diameter tolerance of the ferrule housing chamber 40 of the connector housing 38 that accommodates the ferrule 10 is +/− 0.05 mm and the outer diameter tolerance of the optical fiber 5 is +/− 0.04 mm, the tolerance and the eccentricity are This is because the maximum axis deviation amount of the ferrule 10 calculated from the worst state is 0.25 mm, which is twice ({0.05 + 0.05 + 0.05 + 0.04) / 2} + 0.03 = 0.125.

  As described above, the dimensional accuracy required for the ferrule 10 is stricter than the dimensional accuracy required for a general injection-molded product, but the ferrule 10 of the present embodiment is made using a metal plate having a thickness of about 0.3 mm. In forming, it is possible to perform punching with an accuracy of +/− 0.02 mm or bending with a tolerance of +/− 0.05 mm. Therefore, the ferrule 10 used in the present embodiment can be formed with the dimensional accuracy described above. Such a ferrule can be obtained by a conventional metal sleeve, but is not preferred because of the problem of high cost.

  As shown in FIG. 5, the fixing structure of the optical fiber 5 of the present embodiment is such that the ferrule 10 is inserted into the sleeve-like ferrule housing chamber 40 of the connector housing 38 in the optical connector 36 and held by the ferrule flange 20. Installed by housing. An elastic member 42 such as a coil spring is disposed at the rear part of the ferrule flange 20, and the ferrule 10 is urged toward the ferrule penetration wall 44 side of the ferrule housing chamber 40 by this elastic force. As a result, the ferrule 10 is held in the ferrule housing chamber 40 so as to freely advance and retract in the axial direction. Although not shown from the side of the ferrule housing chamber 40 opposite to the side where the ferrule 10 is inserted, an optical component such as a ferrule 10 or a photoelectric conversion element in another optical fiber 5 fixing structure is inserted and stored. Is done.

  According to the fixing structure of the optical fiber 5 of the present invention, the ferrule 10 used for fixing the optical fiber 5 has the optical fiber insertion hole 16 by bending a part of the punched plate 12 formed by punching a metal plate. An optical fiber aligning portion 14, an optical fiber crimping portion 18, and a ferrule flange portion 20 are provided. Accordingly, since an adhesive that is troublesome to handle, a high-cost metal sleeve, and expensive equipment are not used for fixing the optical fiber 5, the optical fiber 5 can be fixed to the ferrule 10 easily, surely, and at low cost. it can. Further, since the optical fiber 5 is pressure-bonded and fixed by the optical fiber crimping portion 18 and the end of the optical fiber 5 is held by the optical fiber aligning portion 14, the optical fiber 5 is securely fixed without being damaged. Thus, an increase in transmission loss of the optical fiber 5 can be prevented.

  In the present embodiment, the ferrule 10 punches out a metal plate, and a bottom piece 28 that supports the optical fiber 5 in the center, and an optical fiber insertion hole 16 that extends from the head of the bottom piece 28 and into which the optical fiber 5 is inserted. The punching plate 12 having the protruding piece 30 provided, the crimping pieces 32 and 32 and the flange pieces 34 and 34 respectively extending from both side edges of the bottom piece 28 is formed, and the protruding piece 30 of the punching plate 12 is formed. The optical fiber aligning portion 14 is bent and raised, the optical fiber crimping portion 18 is bent by raising the crimping pieces 32 and 32, and the ferrule flange portion 20 is bent and raised. The optical fiber 5 is inserted and fitted into the optical fiber insertion hole 16 of the optical fiber aligning portion 14, and the optical fiber 5 is inserted between the crimping pieces 32 and 32 of the optical fiber crimping portion 18. By entering, by crimping tightening the optical fiber 5 by crimping portions 32, 32, so as to fix the optical fiber 5 in the ferrule 10. According to such a fixing structure of the optical fiber 5 using the ferrule 10, the number of parts is small and the structure is simplified, the manufacturing efficiency of the ferrule 10 can be improved, and the cost of the ferrule 10 can be further reduced. The fixing of the fiber 5 does not take time, and the fixing work efficiency of the optical fiber 5 can be improved.

  Further, as in this embodiment, when the optical fiber crimping portion 18 is provided between the optical fiber aligning portion 14 and the ferrule collar portion 20, the optical fiber crimping portion 18 is closer to the optical fiber aligning portion 14. Accordingly, the distance between the two becomes shorter, so that the optical fiber 5 can be more firmly and stably fixed to the ferrule 10, and the reliability of fixing the optical fiber can be further improved.

  In addition, when the optical fiber 5 is a plastic optical fiber as in the present embodiment, the plastic optical fiber can be securely fixed. Optical communication suitable for increasing the processing amount can be performed accurately.

  Furthermore, according to the optical connector 36 of the present invention, the optical fiber 5 can be easily and surely and efficiently assembled to the connector housing 38 without damaging the optical fiber 5, so that a good quality optical connector 36 is manufactured at low cost. be able to.

  4A and 4B show a modification of the ferrule 10 shown in FIG. 3, where FIG. 4A is a partially omitted front view, and FIG. 4B is a left side view. In this ferrule 46, the outline of the optical fiber insertion hole 50 of the optical fiber aligning portion 48 is not a perfect circle shape like the optical fiber insertion hole 16, but has a flat bottom portion 50a and has a substantially semi-cylindrical shape. Further, as shown in FIG. 4B, the protrusions 52 and 52 for holding the optical fiber 5 are formed inwardly and obliquely upward 30 degrees in the optical fiber insertion hole 50, and as shown in FIG. Thus, it protrudes so as to bend toward the rear optical fiber crimping portion 18 side.

  Then, the end portion of the optical fiber 5 inserted into the optical fiber aligning portion is fitted and supported at three places, that is, the flat bottom portion 50a and the two protrusions 52 and 52. If the protrusions 52 and 52 are bent, the contact area with the optical fiber 5 is increased, so that the optical fiber 5 can be stably supported and the outer surface of the optical fiber 5 is hardly damaged. preferable. Other configurations are the same as those of the ferrule 10, and thus description thereof is omitted. The fixing structure of the optical fiber 5 using the ferrule 46 has the same effect as the fixing structure using the ferrule 10. As long as the number of the protrusions 52 is two or more, the number and position are not limited.

  The protrusions 52 may be provided in three or more locations in the optical fiber insertion hole 16 of the optical fiber aligning portion 14 constituting the ferrule 10, and the optical fibers 5 may be fitted and supported by the protrusions 52. . Moreover, in the said embodiment, although the optical fiber crimping | compression-bonding part 18 of the said ferrules 10 and 46 is provided between the optical fiber aligning parts 14 and 48 and the ferrule collar part 20, the optical fiber crimping | compression-bonding part 18 and ferrule cage | baskets are provided. The arrangement of the part 20 may be changed so that the ferrule collar part 20 is provided between the optical fiber alignment parts 14 and 48 and the optical fiber crimping part 18. A plurality of ferrules 10 and 46 may be provided by bending a part of a punched plate formed by punching a single metal plate. Further, in the above-described embodiment, the fixing structure in the case where the optical fiber 5 is a plastic optical fiber has been described. However, the present invention can also be applied to a fixing structure of a glass-based (quartz-based) optical fiber.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an embodiment of an optical fiber fixing structure according to the present invention, together with its fixing operation process, (a) is a perspective view before fixing an optical fiber, and (b) is after fixing the optical fiber. It is a perspective view of the state. It is a partially omitted plan view of a punched plate formed by punching a metal plate to obtain a ferrule used for fixing an optical fiber. The ferrule obtained by bending a part of punching board of FIG. 2 is shown, (a) is a partially omitted front view, (b) is a left side view. FIG. 4 shows a modified example of the ferrule shown in FIG. 3, (a) is a partially omitted front view, and (b) is a left side view. It is sectional drawing which shows the state which attached the fixing structure of the optical fiber of FIG. 1 to the optical connector. It is a schematic diagram which shows the fixation structure of the conventional optical fiber.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 Optical fiber 10 Ferrule 12 Punching board 14 Optical fiber alignment part 16 Optical fiber insertion hole 18 Optical fiber crimping part 20 Ferrule collar part 20a V-shaped leg 20b Gap 22 Optical fiber strand 24 Primary coating 26 Secondary coating 28 Bottom piece DESCRIPTION OF SYMBOLS 30 Protrusion piece 32 Crimp piece 34 Thread piece 36 Optical connector 38 Connector housing 40 Ferrule accommodating chamber 42 Elastic member 44 Ferrule penetration wall 46 Ferrule 48 Optical fiber alignment part 50 Optical fiber insertion hole 50a Flat bottom part 52 Protrusion

Claims (5)

  In an optical fiber fixing structure for fixing an optical fiber to a ferrule, an optical fiber alignment portion having an optical fiber insertion hole and an optical fiber crimping portion are formed by bending a part of a punched plate formed by punching a metal plate. The optical fiber is inserted into and fitted into the optical fiber insertion hole of the optical fiber alignment portion, and the optical fiber is crimped at the optical fiber crimping portion to attach the optical fiber to the ferrule. An optical fiber fixing structure characterized by being fixed.   The ferrule punches a metal plate to support an optical fiber in the center, a protruding piece having an optical fiber insertion hole extending from the top of the bottom piece to insert an optical fiber, and both side edges of the bottom piece By forming a punched plate having a crimping piece and a flange piece respectively extending, and bending and raising the protruding piece of the punched plate, and bending and raising the crimping piece An optical fiber crimping part and a ferrule collar part are provided by bending and raising the flange piece. The optical fiber is inserted into and fitted into the optical fiber insertion hole of the optical fiber alignment part. 2. The optical fiber according to claim 1, wherein the optical fiber is fixed to the ferrule by inserting an optical fiber between the crimping pieces of the portion and fastening the optical fiber with the crimping piece. Fixed structure.   3. The optical fiber fixing structure according to claim 1, wherein the optical fiber crimping portion of the ferrule is provided between the optical fiber alignment portion and the ferrule collar portion.   4. The optical fiber fixing structure according to claim 1, wherein the optical fiber is a plastic optical fiber.   An optical connector, wherein the optical fiber fixing structure according to claim 1 is attached to a connector housing by housing the ferrule in a ferrule housing chamber of the connector housing.

Images