JP2006126535A - Optical axis alignment structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical axis alignment structure with high accuracy for aligning the optical axes of an optical fiber and a light-emitting element or a light-receiving element by using a lens sleeve. <P>SOLUTION: A joint sleeve 29 is a part to guide a ferrule 23 at an end of an optical fiber 22 and is formed in substantially a cylindrical shape. A plurality of slits 28 are formed in the jointing sleeve 29. The jointing sleeve 29 is formed, in such a manner that the inside diameter h1 in a top end opening 33 of the jointing sleeve 29 can be enlarged to match the outside diameter h2 of an insertion part 34 of the ferrule 23 on guiding the ferrule 23 to be inserted. More specifically, the inside diameter h1 of the top opening 33 of the jointing sleeve 29 is controlled to be smaller than the outside diameter h2 of the insertion part 34 of the ferrule 23 (h1<h2). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical axis alignment structure that performs optical axis alignment between an optical fiber and a light emitting element / light receiving element using a lens sleeve.

  As a conventional lens sleeve which interposes between a ferrule of an optical fiber terminal and a FOT (Fiber Optic Transceiver) having a light emitting element or a light receiving element and performs optical axis alignment, one disclosed in Patent Document 1 below is disclosed. Are known.

  In FIG. 5, a conventional lens sleeve 1 disclosed in Patent Document 1 below is a synthetic resin member that is entirely transparent, and is integrated with a lens portion 3 having a convex lens 2 and the lens portion 3. And a joint sleeve portion 4 to be formed. The lens unit 3 is formed with a FOT mounting portion 6 for the FOT 5. The convex lens 2 is disposed so as to face an element (not shown) of the FOT 5 at a predetermined interval.

The joint sleeve portion 4 is formed in a straight cylindrical shape into which a ferrule 8 provided at the end of the optical fiber 7 can be inserted. Further, the joint sleeve portion 4 is formed to have a sufficient thickness. The inner diameter of the joint sleeve portion 4 is formed to be slightly larger than the outer diameter of the ferrule 8 so that the ferrule 8 can be inserted.
JP 2004-239997 A (page 4, FIG. 2)

  By the way, in the above prior art, since the inner diameter of the joint sleeve portion 4 is formed slightly larger than the outer diameter of the ferrule 8, the optical axis is shifted by the clearance between the joint sleeve portion 4 and the ferrule 8. There is a risk. When the optical axis is shifted, the transmitted optical power is reduced.

  This invention is made | formed in view of the situation mentioned above, and makes it a subject to provide the optical axis alignment structure used as high precision.

  In order to solve the above-mentioned problems, the optical axis alignment structure of the present invention according to claim 1 comprises a light-transmitting lens sleeve formed by integrally molding a joint sleeve portion for guiding a ferrule of an optical fiber terminal into a lens portion. And the lens sleeve is interposed between the element and the ferrule to align the optical axis, and the inner diameter of the tip opening of the joint sleeve portion is smaller than the outer diameter of the insertion portion of the ferrule. The joint sleeve portion is formed with a plurality of slits cut out from the tip opening portion toward the lens portion.

  An optical axis alignment structure according to a second aspect of the present invention is the optical axis alignment structure according to the first aspect, wherein an inner diameter of a base portion of the joint sleeve portion is larger than an outer diameter of the insertion portion of the ferrule. It is characterized by that.

  The optical axis alignment structure of the present invention according to claim 3 is the optical axis alignment structure according to claim 1 or 2, wherein the length of the slit is the length from the tip opening to the end of the lens unit. It is characterized by being formed shorter than that.

  An optical axis alignment structure according to a fourth aspect of the present invention is the optical axis alignment structure according to any one of the first to third aspects, wherein the slit is formed in a tapered shape gradually narrowing toward the lens portion. It is characterized by that.

  According to the present invention, when the ferrule is inserted into the joint sleeve portion of the lens sleeve, the inner diameter of the distal end opening of the joint sleeve portion is enlarged in accordance with the outer diameter of the insertion portion of the ferrule. That is, the present invention has a structure in which the inner diameter of the joint sleeve portion is displaced by the bending of the joint sleeve portion to eliminate the clearance after inserting the ferrule, and as a result, the optical axis can be aligned with high accuracy.

  According to the first aspect of the present invention, it is possible to provide an optical axis alignment structure with high accuracy. Moreover, according to this invention described in Claims 2-4, there exists an effect that the internal-diameter displacement of a joint sleeve part can be displaced better.

  Hereinafter, description will be given with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the optical axis alignment structure of the present invention.

  In FIG. 1, reference numeral 21 denotes a lens sleeve. The lens sleeve 21 is a synthetic resin member interposed between a ferrule 23 provided at the end of the optical fiber 22 and an element 24 (light emitting element or light receiving element), and the whole has light transmittance. It is shaped as follows. The lens sleeve 21 includes a lens portion 27 having convex lenses 25 and 26 and a joint sleeve portion 29 having a slit 28 and integrated with the lens portion 27. Although described in detail below, the lens sleeve 21 is formed so as to perform optical axis alignment with higher accuracy than in the past.

  Here, as a synthetic resin material for molding the lens sleeve 21, a thermoplastic resin material such as PMMA, PC, or PE is taken as an example. It should be noted that only the lens portion 27 can have a light transmitting function by two-color molding.

  The lens unit 27 condenses the convex lenses 25 and 26 in order to condense the optical signal from the optical fiber 22 toward the element 24 or condense the optical signal from the element 24 toward the optical fiber 22. Have. The convex lens 25 is disposed so as to face the element 24 with a predetermined interval. The convex lens 26 is a lens that protrudes in the opposite direction of the convex lens 25, and is disposed so as to face the end surface of the optical fiber 22 at the end surface of the ferrule 23 at a predetermined interval.

  The lens portion 27 is formed with a portion for attaching the lens portion 27 to the other party. In this embodiment, since the element 24 is built in a FOT (Fiber Optic Transceiver) 30, the FOT attachment portion 31 is integrally formed. As will be described later, the lens sleeve 21 is attached to the optical connector housing in this embodiment, and the flange portion 32 is also formed integrally with the lens portion 27 for attachment.

  The FOT attachment portion 31 is formed in a cylindrical shape extending from the peripheral edge of the convex lens 25 by a predetermined length in the protruding direction of the convex lens 25. In addition to the attachment to the FOT 30, the FOT attachment part 31 has a function such that the distance between the convex lens 25 and the element 24 does not become a predetermined value or less. The flange portion 32 is formed to protrude so as to be orthogonal to the outer peripheral surface of the lens portion 27.

  The joint sleeve portion 29 is a portion for guiding the ferrule 23 at the end of the optical fiber 22, and is formed in a substantially cylindrical shape extending from the peripheral edge of the convex lens 26 by a predetermined length in the protruding direction of the convex lens 26. Yes. As described above, a plurality of slits 28 are formed in the joint sleeve portion 29 (the number of the slits 28 depends on the rigidity of the joint sleeve portion 29, but the joint sleeve portion 29 can be divided by about 2 to 6). If possible.) When the joint sleeve portion 29 guides the ferrule 23 to be inserted, the inner diameter h1 of the tip opening portion 33 of the joint sleeve portion 29 can be enlarged in accordance with the outer diameter h2 of the insertion portion 34 of the ferrule 23. Is formed.

  Specifically, the inner diameter h1 of the tip opening 33 of the joint sleeve portion 29 is formed smaller than the outer diameter h2 of the insertion portion 34 of the ferrule 23 (h1 <h2 For example, the tip opening 33 is an end surface taper of the ferrule 23. It is made small so as to contact the portion 35). Further, the inner diameter h3 of the base portion 36 of the joint sleeve portion 29 is formed larger than the outer diameter h2 of the insertion portion 34 of the ferrule 23 (h2 <h3). The joint sleeve portion 29 is formed in a shape that is slightly tapered toward the distal end opening portion 33.

  The slit 28 is cut out from the tip opening 33 toward the lens unit 27. Such a slit 28 is formed such that its length h4 is shorter than the length h5 from the tip opening 33 to the protruding tip of the convex lens 26 (h4 <h5). Further, the slit 28 is formed such that the innermost width h6 is narrower than the width h7 in the tip opening 33 (h6 <h7 <h1). The slit 28 is formed in a tapered shape that becomes gradually narrower toward the lens portion 27.

  Next, an application example of the optical axis alignment structure of the present invention will be described based on the above configuration with reference to FIGS. 2 is a cross-sectional view before optical connector fitting, FIG. 3 is a cross-sectional view during optical connector fitting (before inserting a ferrule), and FIG. 4 is a cross-sectional view during ferrule insertion. The following description is an example. Refer to FIG. 1 as necessary.

  In FIG. 2, the lens sleeve 21 and the FOT 30 are provided as constituent members of a receptacle-type optical connector 37, and are respectively attached to predetermined positions of the optical connector housing 38. Reference numeral 39 indicates a shielding case covering the periphery of the FOT 30, that is, a shielding case. The ferrule 23 provided at the end of the optical fiber 22 is provided as a constituent member of a plug-type optical connector 40 and attached to a predetermined position of the optical connector housing 41. The ferrule 23 is positioned by the positioning pin member 44 with the flange 42 in contact with the stepped portion 43 of the optical connector housing 41. Reference numeral 45 indicates a through hole into which the lens sleeve 21 is inserted. The end face of the ferrule 23 can be faced from the through hole 45.

  FIG. 2 shows a state before the optical connector is fitted and the optical connectors 37 and 40 face each other. As shown in FIG. 3, when the optical connector housing 41 of the optical connector 40 is inserted into the optical connector housing 38 of the optical connector 37 and fitting is started from this state, the distal end opening of the joint sleeve portion 29 in the lens sleeve 21 is started. 33 abuts against the end face taper portion 35 of the ferrule 23. Then, when the tip opening 33 slidably contacts the end face taper portion 35, the tip opening 33 of the joint sleeve portion 29 expands in accordance with the insertion portion 34 of the ferrule 23 (the joint sleeve portion 29 has a slit 28). And is displaced in the direction in which the inner diameter h1 of the tip opening 33 is enlarged). As a result, as shown in FIG. 4, the ferrule 23 is guided into the joint sleeve portion 29 with no clearance between the tip opening portion 33 and the insertion portion 34 (h1 = h2 and the insertion clearance is Is kept at zero). Thereafter, although not particularly illustrated, when the fitting between the optical connectors 37 and 40 is completed, the convex lens 26 and the end face of the ferrule 23 (end face of the optical fiber 22) face each other with a predetermined interval. The optical axis is aligned with high accuracy by the lens sleeve 21.

  As described above with reference to FIGS. 1 to 4, according to the present invention, when the ferrule 23 is inserted into the joint sleeve portion 29 of the lens sleeve 21, the distal end opening portion 33 of the joint sleeve portion 29 is formed. The inner diameter h1 can be enlarged in accordance with the outer diameter h2 of the insertion portion 34 of the ferrule 23. In other words, according to the present invention, the inner diameter h1 of the joint sleeve portion 29 can be displaced by the bending of the joint sleeve portion 29, so that the clearance after insertion of the ferrule 23 can be eliminated. Therefore, highly accurate optical axis alignment can be performed.

  In addition, it goes without saying that the present invention can be variously modified without departing from the spirit of the present invention.

It is sectional drawing which shows one Embodiment of the optical axis alignment structure of this invention. It is sectional drawing before optical connector fitting. It is sectional drawing during optical connector fitting (before ferrule insertion). It is sectional drawing during ferrule insertion. It is sectional drawing of the lens sleeve of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 21 Lens sleeve 22 Optical fiber 23 Ferrule 24 Element 25, 26 Convex lens 27 Lens part 28 Slit 29 Joint sleeve part 30 FOT (Fiber Optic Transceiver)
31 FOT mounting portion 32 Flange portion 33 Tip opening portion 34 Insertion portion 35 End face taper portion 36 Base portion 37, 40 Optical connector 38, 41 Optical connector housing 39 Shield case 42 Flange 43 Step portion 44 Positioning pin member 45 Through hole h1 Tip opening Inner diameter h2 Outer diameter of insertion part h3 Inner diameter of base h4 Length of slit h5 Length from tip opening to protruding tip of convex lens h6 Width of slit innermost part h7 Slit width at tip opening

Claims (4)

A structure comprising a light-transmitting lens sleeve formed integrally with a lens portion with a joint sleeve portion for guiding a ferrule of an optical fiber terminal, and performing optical axis alignment by interposing the lens sleeve between the element and the ferrule In
An inner diameter of the distal end opening of the joint sleeve portion is formed to be smaller than an outer diameter of the insertion portion of the ferrule, and a plurality of slits cut out from the distal end opening toward the lens portion are formed in the joint sleeve portion. An optical axis alignment structure characterized by that. In the optical axis alignment structure according to claim 1,
An optical axis alignment structure, wherein an inner diameter of a base portion of the joint sleeve portion is formed larger than an outer diameter of the insertion portion of the ferrule. In the optical axis alignment structure according to claim 1 or claim 2,
The length of the slit is formed shorter than the length from the tip opening to the end of the lens part. The optical axis alignment structure according to any one of claims 1 to 3,
The optical axis alignment structure, wherein the slit is formed in a tapered shape that gradually becomes narrower toward the lens portion.

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