Method for manufacturing optical connector

Abstract

To reduce a manufacturing cost of an optical connector.SOLUTION: An optical connector 1 comprises a ferrule 10, a plug frame 20, and an elastic member 19. The ferrule holds a glass fiber of an optical fiber. The plug frame accommodates the ferrule. The elastic member urges the ferrule along the direction of the central axis of the ferrule. The elastic member holds the ferrule at a first position P1 in the plug frame at a first length, or holds the ferrule at a second position P2 in the plug frame at a second length shorter than the first length. The ferrule or the plug frame has a tapered surface. When the ferrule is at the first position, the ferrule and the plug frame are brought into contact with each other via the tapered surface, and rotation of the ferrule relative to the plug frame is regulated. When the ferrule is at the second position, the ferrule and the plug frame are not brought into contact with each other; the ferrule is rotatable relative to the plug frame; and the ferrule is in a floating state relative to the plug frame.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to an optical connector and an optical connection structure. This application claims priority based on Japanese Application No. 2019-004071 filed on January 15, 2019, and incorporates all the descriptions described in the above Japanese application.

Background Art

[0002] An optical connector has a ferrule that holds an optical fiber and a plug frame that houses the ferrule. Even when an external force is applied to the plug frame, it is required to maintain the optical connection state between the cores of the respective optical fibers. Non-Patent Document 1 discloses a structure in which the ferrule is floated with respect to the plug frame so that an external force applied to the plug frame (plug housing) does not reach the ferrule. This structure employs an Oldham coupling mechanism. A coupling component is interposed between a flange provided on the ferrule and the plug frame, and the ferrule is movable in one direction (left-right direction) perpendicular to the ferrule central axis with respect to the coupling component, and the coupling component is movable in a direction (up-down direction) perpendicular to the ferrule central axis and the one direction with respect to the plug frame.

Prior Art Documents

Non-Patent Documents

[0003]

Non-Patent Document 1

Summary of the Invention

Means for Solving the Problems

[0004] An optical connector according to one aspect of the present disclosure comprises a ferrule, a plug frame, and an elastic member. The ferrule has a flange on the outside and a through hole on the inside, and is capable of holding the glass fiber exposed from the resin coating at one end of an optical fiber, which includes a glass fiber and a resin coating covering the glass fiber. The plug frame is configured to house the ferrule. The elastic member biases the ferrule along the central axis direction of the ferrule. The elastic member is capable of holding the ferrule in a first position within the plug frame by a first length of the elastic member, and is capable of holding the ferrule in a second position within the plug frame by a second length shorter than the first length.

[0005] Either the ferrule or the plug frame has at least one pair of tapered surfaces that are opposed to each other and whose distance from the central axis of the ferrule decreases in the biasing direction of the elastic member. When the ferrule is in the first position, the ferrule and the plug frame are in contact via the at least one pair of tapered surfaces, restricting the rotation of the ferrule relative to the plug frame. When the ferrule is in the second position, the ferrule and the plug frame are not in contact, the ferrule is rotatable relative to the plug frame, and the ferrule is floating relative to the plug frame.

[0006] Furthermore, an optical connector according to one aspect of the present disclosure comprises a ferrule, a plug frame, and an elastic member. The ferrule has a flange on the outside and a through hole on the inside, and is capable of holding the glass fiber exposed from the resin coating at one end of an optical fiber, which includes a glass fiber and a resin coating covering the glass fiber, within the through hole. The plug frame is configured to house the ferrule and has a clearance portion at the rearmost opening, a rotation restricting portion in front of the clearance portion, and an opening in front of the rotation restricting portion. The elastic member biases the ferrule along the central axis direction of the ferrule. The optical fiber requires adjustment of the rotation angle around the central axis when optically connecting the optical fibers. The elastic member is capable of holding the ferrule in a first position within the plug frame by a first length of the elastic member, and is capable of holding the ferrule in a second position within the plug frame by a second length shorter than the first length.

[0007] The flange of the ferrule has two pairs of flat surfaces extending along the central axis and a mark indicating a reference for the rotational position. The rotation restricting portion of the plug frame has a pair of tapered surfaces and a pair of opposing flat surfaces, the distance from the central axis of the ferrule decreasing in the biasing direction of the elastic member. When the ferrule is in the first position, each of the two pairs of flat surfaces of the ferrule contacts each of the pair of tapered surfaces of the plug frame, restricting the rotation of the ferrule relative to the plug frame. When the ferrule is in the second position, the ferrule does not contact the plug frame, the ferrule is rotatable relative to the plug frame, and the ferrule is floating relative to the plug frame. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is an external perspective view showing an optical connector according to one aspect of this disclosure, with an optical fiber incorporated. [Figure 2] Figure 2 is a perspective view of the ferrule included in the optical connector shown in Figure 1. [Figure 3]Figure 3 is a perspective view of the front housing that constitutes the plug frame of the optical connector shown in Figure 1. [Figure 4A] Figure 4A is a cross-sectional view taken along line AA in Figure 3. [Figure 4B] Figure 4B is a cross-sectional view taken along the line BB in Figure 3. [Figure 4C] Figure 4C is a cross-sectional view taken along the line CC in Figure 3. [Figure 5] Figure 5 is a cross-sectional view showing the state before the ferrule is housed in the plug frame. [Figure 6] Figure 6 is a cross-sectional view showing the state after the ferrule has been housed in the plug frame. [Figure 7] Figure 7 is a cross-sectional view showing the ferrule after the split sleeve has been attached. [Figure 8] Figure 8 is a diagram illustrating bundled fibers. [Figure 9A] Figure 9A is a perspective view of a ferrule according to another embodiment. [Figure 9B] Figure 9B is a front view of a ferrule according to another embodiment. [Figure 10A] Figure 10A is a plan cross-sectional view of a front housing according to another embodiment. [Figure 10B] Figure 10B is a side cross-sectional view of the front housing according to another embodiment. [Modes for carrying out the invention]

[0009] [Issues this disclosure aims to address] In the structure described in Non-Patent Document 1, the flange is divided into multiple parts and moved in the vertical and horizontal directions, which increases the number of components in the optical connector and makes the structure complex, making it difficult to reduce the manufacturing cost of the optical connector.

[0010] First, the embodiments of this disclosure will be listed and described. (1) An optical connector according to one aspect of the present disclosure comprises a ferrule, a plug frame, and an elastic member. The ferrule has a flange on the outside and a through hole on the inside, and is capable of holding the glass fiber exposed from the resin coating at one end of an optical fiber, which includes a glass fiber and a resin coating covering the glass fiber. The plug frame is configured to house the ferrule. The elastic member biases the ferrule along the central axis direction of the ferrule. The elastic member is capable of holding the ferrule in a first position within the plug frame by a first length of the elastic member, and is capable of holding the ferrule in a second position within the plug frame by a second length shorter than the first length.

[0011] Either the ferrule or the plug frame has at least one pair of tapered surfaces that are opposed to each other and whose distance from the central axis of the ferrule decreases in the biasing direction of the elastic member. When the ferrule is in the first position, the ferrule and the plug frame are in contact via the at least one pair of tapered surfaces, restricting the rotation of the ferrule relative to the plug frame. When the ferrule is in the second position, the ferrule and the plug frame are not in contact, the ferrule is rotatable relative to the plug frame, and the ferrule is floating relative to the plug frame.

[0012] In such an optical connector, until the ferrule is moved from the first position to the second position, the ferrule and the plug frame are in contact with each other, so that the ferrule is positioned with respect to the plug frame and rotation is also restricted. On the other hand, after the ferrule is moved from the first position to the second position, the contact state between the ferrule and the plug frame is released, and the ferrule is floated with respect to the plug frame. Therefore, even when an external force is applied to the plug frame, it will not be transmitted to the ferrule. In this way, the tapered surface alone achieves the positioned state and the floating state of the ferrule with respect to the plug frame, reducing the number of parts of the optical connector and simplifying the structure of the optical connector. In addition, since the height of the ferrule or the height and width of the plug frame gradually decrease in the biasing direction, it is easier to insert the ferrule from the rear of the plug frame. Further, when the ferrule is advanced in the biasing direction, the gap between the ferrule and the plug frame becomes smaller, facilitating the positioning of the ferrule with respect to the plug frame.

[0013] (2) An optical connector according to one aspect of the present disclosure comprises a ferrule, a plug frame, and an elastic member. The ferrule is provided with a flange having two pairs of flat surfaces extending outward along the central axis direction, and has a through hole on the inside, and is capable of holding the glass fiber exposed from the resin coating at one end of an optical fiber including a glass fiber and a resin coating covering the glass fiber within the through hole. The plug frame is configured to house the ferrule and has a clearance portion at the rearmost opening, a rotation restricting portion in front of the clearance portion, and an opening in front of the rotation restricting portion. The elastic member biases the ferrule along the central axis direction of the ferrule. The optical fiber requires adjustment of the rotation angle around the central axis when the optical fibers are optically connected to each other. The elastic member is capable of holding the ferrule in a first position within the plug frame by a first length of the elastic member, and is capable of holding the ferrule in a second position within the plug frame by a second length shorter than the first length. The flange of the ferrule has two pairs of flat surfaces extending along the central axis and a mark indicating a reference for the rotational position. The rotation restricting portion of the plug frame has a pair of tapered surfaces and a pair of opposing flat surfaces, the distance from the central axis of the ferrule decreasing in the biasing direction of the elastic member. When the ferrule is in the first position, each of the two pairs of flat surfaces of the ferrule contacts each of the pair of tapered surfaces of the plug frame, restricting the rotation of the ferrule relative to the plug frame. When the ferrule is in the second position, the ferrule does not contact the plug frame, the ferrule is rotatable relative to the plug frame, and the ferrule is floating relative to the plug frame.

[0014] [Effect of the present disclosure] According to the optical connector of the present disclosure, the number of parts can be reduced and the structure can also be simplified.

[0015] [Embodiment of the present disclosure] Hereinafter, embodiments of the optical connector and the optical connection structure according to the present disclosure will be described with reference to the drawings. In the following description, components denoted by the same reference numerals in different drawings may be the same, and the description thereof may be omitted. Note that the present disclosure is not limited to the examples in these embodiments, and includes all modifications within the scope and equivalent scope of the matters described in the claims. In addition, as long as combinations of multiple embodiments are possible, the present disclosure includes combinations of any embodiments.

[0016] [An example of the optical connector of the present disclosure] Figure 1 is an external perspective view of an optical connector 1 according to one aspect of the present disclosure, with an optical fiber incorporated. Figure 2 is a perspective view of the ferrule 10 included in the optical connector 1, and Figure 3 is a perspective view of the front housing 21 constituting the plug frame 20 of the optical connector 1. Furthermore, Figure 4A is a cross-sectional view taken along line AA in Figure 3, Figure 4B is a cross-sectional view taken along line BB in Figure 3, and Figure 4C is a cross-sectional view taken along line CC in Figure 3. Figure 5 is a cross-sectional view showing the state before the ferrule 10 is housed in the plug frame 20. In the following description, the optical connector will be explained using an LC connector as an example.

[0017] As shown in Figure 1, the optical connector 1 includes a plug frame 20 that houses the ferrule 10, and a boot 34 is provided at the rear end of the plug frame 20 to protect the optical fiber F.

[0018] [ferrule] As shown in Figure 2, the ferrule 10 has a ferrule body 11 extending in the X-axis direction as shown in the figure. The ferrule body 11 is cylindrical and made of, for example, zirconia, and has a through hole on the inside of the ferrule body 11. The glass fiber exposed from the resin coating of the tip portion (one end) of the optical fiber F is held in the through hole. The optical fiber F is, for example, a multicore fiber having multiple cores, and is inserted from the rear end 13 of the ferrule body 11, with its tip surface exposed from the front end 12, and is fixed to the ferrule 10 with multiple cores arranged at predetermined positions around the central axis of the ferrule 10. In the drawing, the direction of the axis of the through hole is represented as the X-axis. Hereafter, the direction of the through hole will also be referred to as the optical axis direction of the optical fiber F.

[0019] A flange 14, for example made of metal, is provided on the outside of the ferrule body 11 at approximately the center. The flange 14 has, for example, a roughly polygonal shape in cross-section (roughly quadrilateral in Figure 2) and has an upper surface 15, a lower surface (flat surface) 16, a left side surface 17, and a right side surface 18 that form the outer circumferential surface of the flange 14. The upper surface 15 and the lower surface 16 face each other across the optical axis of the optical fiber F and are parallel flat surfaces separated by a predetermined distance in the Z-axis direction as shown in the figure. The left side surface 17 and the right side surface 18 are perpendicular to the upper surface 15 and the lower surface 16 and both face each other across the optical axis of the optical fiber F and are parallel flat surfaces separated by a predetermined distance in the Y-axis direction as shown in the figure. The boundary positions between the upper surface 15 and the left side surface 17 and the right side surface 18, and the boundary positions between the lower surface 16 and the left side surface 17 and the right side surface 18 are chamfered. If a mark (not shown) is placed on the top surface 15 to indicate the reference position of rotation, the ferrule 10 can be inserted into the plug frame 20 in the correct orientation.

[0020] [Front housing of the plug frame] As shown in Figure 3, the plug frame 20 has a rectangular tubular front housing 21 extending in the X-axis direction as shown in the figure. The front housing 21 is made of resin, for example, and has a rear end opening 24 that can receive a ferrule 10 with a flange 14, and a front end opening 23 that allows the front end 12 of the ferrule body 11 described in Figure 2 to protrude. A flexible latch arm 22 is provided on the outer circumferential surface of the front housing 21.

[0021] As shown in Figures 4A to 4C, the interior of the front housing 21 is divided into a clearance portion 25 at the rearmost opening 24 side (negative direction of the X-axis in the figures, the same applies hereafter), a rotation restricting portion 26 in front of this clearance portion 25, and a roughly rectangular cylindrical opening 27 in front of this rotation restricting portion 26.

[0022] The clearance portion 25 does not engage with the flange 14 of the ferrule 10 and has an upper surface 25a, a lower surface 25b, a left side surface 25c, and a right side surface 25d, as shown in Figures 4A to 4C. The upper surface 25a and the lower surface 25b are parallel to each other at a predetermined distance in the Z-axis direction as shown, and the left side surface 25c and the right side surface 25d are parallel to each other at a predetermined distance in the Y-axis direction as shown. Therefore, the clearance portion 25 is a rectangular tubular internal space consisting of the upper surface 25a, the lower surface 25b, the left side surface 25c, and the right side surface 25d, but the distance from the upper surface 25a to the lower surface 25b (length in the Z-axis direction as shown, the same applies hereafter) is greater than the thickness of the flange 14 (distance between the upper surface 15 and the lower surface 16). As a result, the ferrule 10 with the flange 14 can float when the flange 14 is in the clearance portion 25.

[0023] As shown in Figures 4A to 4C, the rotation restricting section 26 has tapered surfaces (first tapered surface 26a, second tapered surface 26b), a left side surface 26c, and a right side surface 26d that restrict the rotation of the ferrule 10. The tapered surfaces, the first tapered surface 26a and the second tapered surface 26b, are at a distance from each other across the optical axis in the Z-axis direction as shown in the figure, while the left side surface 26c and the right side surface 26d are parallel to each other at a predetermined distance in the Y-axis direction as shown in the figure.

[0024] More specifically, the distance between the first tapered surface 26a and the second tapered surface 26b and the optical axis decreases in the direction of biasing the coil spring 19. The coil spring 19 will be described later. The distance in the Z-axis direction between the front end of the first tapered surface 26a and the front end of the second tapered surface 26b is smaller than the thickness of the flange 14 of the ferrule 10 (distance between the upper surface 15 and the lower surface 16), and the distance in the Z-axis direction between the rear end of the first tapered surface 26a and the rear end of the second tapered surface 26b is larger than the thickness of the flange 14 of the ferrule 10 (distance between the upper surface 15 and the lower surface 16).

[0025] In this way, the distance between the upper and lower surfaces inside the front housing 21 is gradually shortened from the clearance portion 25 towards the rotation restricting portion 26, making it easier to insert the ferrule 10 from the rear of the front housing 21 and to position the ferrule 10 on the front housing 21.

[0026] [Rear housing of the plug frame] As shown in Figure 5, the plug frame 20 has a rear housing 31 behind the front housing 21. The rear housing 31 is made of resin, for example, and has a cylindrical spring housing 33 capable of accommodating the rear end portion of the ferrule 10 and the coil spring (elastic member) 19. The coil spring 19 is positioned behind the ferrule 10 and contacts the rear end of the flange 14, biasing the ferrule 10 forward (in the positive direction of the X-axis in the figure, the same applies hereafter).

[0027] A clip 32 that can engage with the latch arm 22 is provided on the outer circumferential surface of the rear housing 31. The rear end portion of the ferrule 10 and the coil spring 19 are housed in the rear housing 31, and the front end portion of the ferrule 10 is inserted into the front housing 21. The flange 14 can be placed on the lower surface 25b of the front housing 21 at the position of the clearance portion 25.

[0028] Next, when the clip 32 rides onto the latch arm 22, the front housing 21 is latched to the rear housing 31. At the same time, the flange 14 is pushed forward by the biasing force of the coil spring 19, and the upper surface 15 of the flange 14 moves forward along the first tapered surface 26a of the front housing 21, or the lower surface 16 of the flange 14 moves forward along the second tapered surface 26b of the front housing 21. As the flange 14 moves forward, as shown in Figure 6, when the upper surface 15 of the flange 14 comes into contact with the first tapered surface 26a of the front housing 21, or the lower surface 16 of the flange 14 comes into contact with the second tapered surface 26b of the front housing 21 (hereinafter, the position of the ferrule 10 within the plug frame 20 at this time will be referred to as "first position P1"), the front end 12 of the ferrule 10 protrudes from the front housing 21. At this time, the flange 14 is sandwiched between the first tapered surface 26a and the second tapered surface 26b of the front housing 21, and the flange 14 is held in a state where rotation is restricted relative to the front housing 21 and movement in the Z-axis direction is difficult at the first position P1. The length of the coil spring 19 at this time is defined as the first length L1.

[0029] [An example of an optical connection structure in this disclosure] Next, as shown in Figure 6, the optical connection structure comprises an optical connector 1 and another optical connector 1', and uses a split sleeve (sleeve) 40 to optically connect the optical fiber F on the optical connector 1 side and the optical fiber F' (not shown) on the optical connector 1' side. The optical fiber F' is also a multicore fiber having multiple cores, and is fixed to the ferrule 10' with multiple cores arranged at predetermined positions around the central axis of the ferrule 10'. The optical connector (object to be connected) 1' is not shown in the cross-sectional view, but it is configured similarly to the optical connector 1, and has a ferrule 10' holding the optical fiber F' and an elastic member (not shown) that biases the ferrule 10' within the plug frame 20'.

[0030] The split sleeve 40 has an inner diameter that is approximately equal to, or slightly smaller than, the diameter of the ferrules 10,10'. The split sleeve 40 also has a slit (not shown), and the inner diameter can be increased by widening this slit. The split sleeve 40 may also be built into an adapter (a component for connecting connectors of the same or different types, e.g., http: / / www.optigate.jp / products / connector / adapter.html).

[0031] As shown in Figure 6, the ferrule 10 is inserted from one end of the split sleeve 40, and the ferrule 10' is inserted from the other end of the split sleeve 40, so that the end face of the optical fiber F on the ferrule 10 side and the end face of the optical fiber F' on the ferrule 10' side make surface contact within the split sleeve 40 (also called connector connection). As shown in Figure 7, when the split sleeve 40 enters the front housing 21 and the ferrule 10 moves to the second position P2, which is behind the first position P1 (i.e., when the coil spring 19 becomes a second length L2 which is shorter than the first length L1), the flange 14 moves backward against the biasing force of the coil spring 19, so that the contact between the tapered surface of the front housing 21 (first tapered surface 26a and second tapered surface 26b) and the upper surface 15 and lower surface 16 of the flange 14 is released. At this time, the ferrule 10 is held in the second position P2 within the plug frame 20 by the split sleeve 40 and the coil spring 19.

[0032] Then, when the flange 14 reaches the position of the clearance portion 25, the ferrule 10 becomes floating, not positioned relative to the front housing 21, and becomes movable in any direction of the X, Y, or Z axis, and can also rotate around the optical axis together with the optical fiber F' on the optical connector 1' side.

[0033] In this way, until optical connector 1 and optical connector 1' are connected (until the ferrule 10 is moved from front to back), the upper surface 15 and lower surface 16 of the flange 14 and the tapered surface (first tapered surface 26a and second tapered surface 26b) of the front housing 21 are in contact, so the ferrule 10 is positioned relative to the front housing 21 and rotation is prevented. Therefore, by facing the plug frame 20 against the plug frame 20', each of the multiple cores contained in the optical fiber F and each of the multiple cores contained in the optical fiber F' can be precisely faced.

[0034] On the other hand, after connecting optical connector 1 and optical connector 1' (after moving the ferrule 10 backward: when the connectors are connected), the contact between the upper surface 15 and lower surface 16 of the flange 14 and the tapered surface (first tapered surface 26a and second tapered surface 26b) of the front housing 21 is released, and the ferrule 10 floats relative to the front housing 21. As a result, even if an external force is applied to the front housing 21 or the rear housing 31, the external force is not transmitted to the ferrule 10, and the optical connection state between the two optical fibers F and optical fiber F' can be maintained.

[0035] In this way, the positioning and floating states of the ferrule 10 relative to the front housing 21 are achieved simply by the placement of the upper surface 15 and lower surface 16 of the flange 14 and the tapered surface (first tapered surface 26a and second tapered surface 26b) of the front housing 21. This reduces the number of parts in the optical connector 1 and simplifies the structure of the optical connector 1. As a result, it is possible to provide an optical connection structure that is simple in structure and easy to maintain the optical connection state.

[0036] By the way, in the above embodiment, an example was given in which the upper surface 15 and lower surface 16 of the flange 14 are clamped by the tapered surface (first tapered surface 26a and second tapered surface 26b) of the front housing 21 when the upper surface 15 and lower surface 16 of the flange 14 are in contact with the tapered surface (first tapered surface 26a and second tapered surface 26b) of the front housing 21. However, the disclosure is not limited to this example, and the front housing 21 may have tapered surfaces on its sides. In other words, the surface designated as the first tapered surface 26a and the surface designated as the second tapered surface 26b may be simply flat surfaces, the left side surface 26c may be the first tapered surface, and the right side surface 26d may be the second tapered surface.

[0037] Furthermore, although the optical connector was described using an LC connector as an example in the above embodiment, this disclosure can also be applied to other types of optical connectors, including, for example, SC connectors and MU connectors. Furthermore, optical fiber F was explained using the example of a multicore fiber. However, the optical fibers of this disclosure may be, for example, single-mode fibers, polarization-maintaining fibers, or bundled fibers. Multicore fibers, polarization-maintaining fibers, and bundled fibers are optical fibers that require adjustment of the rotation angle around the central axis when optically connecting them.

[0038] A bundled fiber is a fiber made up of multiple single-core fibers bundled together for optical connection with a multi-core fiber. For example, a single-core fiber with a glass diameter of 125 μm is prepared by chemically etching the tip to reduce its diameter to, for example, 45 μm. As shown in Figure 8, multiple fibers (for example, seven) are bundled together with adhesive and inserted into the ferrule 10. In this example, the fibers can be arranged so that the distance between cores is 45 μm. In this way, reliable positioning can be achieved not only when using single-mode fibers, but also when using multi-core fibers, polarization-maintaining fibers, and bundled fibers, thus preventing a decrease in connection loss.

[0039] [Other embodiments] In the embodiments described above, an example of an optical connector 1 consisting of a ferrule 10 having a flange 14 with a substantially rectangular cross-sectional shape and a plug frame 20 having a front housing 21 with a tapered surface was given. However, the optical connector of the present disclosure may also have a tapered surface on the ferrule and a flat surface inside the front housing of the plug frame, which will be described in detail below.

[0040] [ferrule] As shown in Figures 9A and 9B, for example, the upper surface 15 of the flange 14 of the ferrule 10 has a flat surface 15a and a first tapered surface 15b located on the biasing side of the flat surface 15a. Similarly to the upper surface 15, the lower surface 16 of the flange 14 of the ferrule 10 also has a flat surface 16a and a second tapered surface 16b located on the biasing side of the flat surface 16a.

[0041] The flat surfaces 15a and 16a face each other across the optical axis of the optical fiber F and are parallel to each other at a predetermined distance in the Z-axis direction as shown in the figure. The first tapered surface 15b and the second tapered surface 16b face each other across the optical axis, and the distance between the first tapered surface 15b and the second tapered surface 16b and the optical axis decreases in the biasing direction. The distance in the Z-axis direction between the rear end of the first tapered surface 15b and the rear end of the second tapered surface 16b is greater than the distance in the Z-axis direction between the flat surfaces 15a and 16a.

[0042] [plug frame] Furthermore, although the above-described embodiment was explained in which the rotation restricting portion 26 of the front housing 21 has tapered surfaces (first tapered surface 26a and second tapered surface 26b), in this embodiment the ferrule 10 side has tapered surfaces, so the front housing 21 has flat surfaces instead of tapered surfaces. Specifically, as shown in Figures 10A and 10B, the rotation restricting portion 26 has an upper surface 261a, a lower surface 261b, a left side surface 26c, and a right side surface 26d. The upper surface 261a and the lower surface 261b are parallel to each other at a predetermined distance in the Z-axis direction shown in the figure, and the left side surface 26c and the right side surface 25d are parallel to each other at a predetermined distance in the Y-axis direction shown in the figure. The distance in the Z-axis direction between the upper surface 261a and the lower surface 261b is greater than the distance in the Z-axis direction between the front end of the first tapered surface 26a and the front end of the second tapered surface 26b, and less than the distance in the Z-axis direction between the rear end of the first tapered surface 26a and the rear end of the second tapered surface 26b.

[0043] In this way, the distance in the Z-axis direction between the first tapered surface 26a and the second tapered surface 26b is gradually reduced from the rear end to the front end, making it easier to insert the ferrule 10 from the rear of the front housing 21 and to position the ferrule 10 on the front housing 21.

[0044] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims, not in the sense described herein, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of Symbols]

[0045] 1,1'...Optical connector, 10,10'...Ferrule, 11...Ferrule body, 12...Front end, 13...Rear end, 14...Flange, 15...Top surface, 15a...Flat surface, 15b...First tapered surface, 16...Bottom surface, 16a...Flat surface, 16b...Second tapered surface, 17...Left side, 18...Right side, 19...Coil spring, 20,20'...Plug frame, 21...Front housing, 22...Latch arm, 23...Front end opening, 24...Rear end opening, 25...Clear 25a...Top surface, 25b...Bottom surface, 25c...Left side surface, 25d...Right side surface, 26...Rotation restricting part, 26a...First tapered surface, 261a...Top surface, 26b...Second tapered surface, 261b...Bottom surface, 26c...Left side surface, 26d...Right side surface, 27...Opening, 31...Rear housing, 32...Clip, 33...Spring housing part, 34...Boot, 40...Split sleeve, P1...First position, P2...Second position, L1...First length, L2...Second length, F...Optical fiber

Claims

1. An optical fiber having a flange on the outside and a through hole on the inside, the through hole containing a glass fiber and a resin coating covering the glass fiber, and a ferrule capable of holding the glass fiber exposed from the resin coating at one end of the optical fiber, A plug frame configured to accommodate the ferrule, An optical connector comprising an elastic member that biases the ferrule along the central axis direction of the ferrule, The elastic member is capable of holding the ferrule in a first position within the plug frame with a first length, and is capable of holding the ferrule in a second position within the plug frame with a second length shorter than the first length. Either the ferrule or the plug frame has at least one pair of tapered surfaces that are opposed to each other and whose distance from the central axis of the ferrule decreases in the direction of biasing the elastic member, When the ferrule is in the first position, the ferrule and the plug frame are in contact via the at least pair of tapered surfaces, and rotation of the ferrule relative to the plug frame is restricted. When the ferrule is in the second position, the ferrule and the plug frame do not come into contact, the ferrule is rotatable relative to the plug frame, and the ferrule is floating relative to the plug frame. Optical connector.

2. A ferrule having a flange on the outside and a through hole on the inside, the through hole containing a glass fiber and a resin coating covering the glass fiber, and a ferrule capable of holding the glass fiber exposed from the resin coating at one end of the optical fiber, A plug frame configured to accommodate the ferrule, An optical connector comprising an elastic member that biases the ferrule along the central axis direction of the ferrule, When optically connecting the optical fibers, it is necessary to adjust the rotation angle around the central axis. The flange of the ferrule has two pairs of flat surfaces extending along the central axis and marks indicating a reference position for rotation, The plug frame has a clearance portion at the rearmost opening, a rotation restricting portion in front of the clearance portion, and an opening in front of the rotation restricting portion. The elastic member is capable of holding the ferrule in a first position within the plug frame with a first length, and is capable of holding the ferrule in a second position within the plug frame with a second length shorter than the first length. The rotation restricting portion of the plug frame has a pair of tapered surfaces and a pair of opposing flat surfaces, the distance from the central axis of the ferrule decreases in the direction of biasing the elastic member, and these surfaces face each other. When the ferrule is in the first position, each of the two pairs of flat surfaces of the ferrule contacts each of the pair of tapered surfaces of the plug frame, thereby restricting the rotation of the ferrule relative to the plug frame. When the ferrule is in the second position, the ferrule and the plug frame do not come into contact, the ferrule is rotatable relative to the plug frame, and the ferrule is floating relative to the plug frame. Optical connector.

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