U.S. patent application number 17/094148 was filed with the patent office on 2021-02-25 for pigtail-type optical receptacle.
The applicant listed for this patent is TOTO LTD.. Invention is credited to Hirotsugu AGATSUMA, Satoshi HAKOZAKI, Satoshi KANEYUKI, Sho KONDO, Hiroki SATO, Kohei TOMINAGA.
Application Number | 20210055484 17/094148 |
Document ID | / |
Family ID | 1000005210235 |
Filed Date | 2021-02-25 |
View All Diagrams
United States Patent
Application |
20210055484 |
Kind Code |
A1 |
TOMINAGA; Kohei ; et
al. |
February 25, 2021 |
PIGTAIL-TYPE OPTICAL RECEPTACLE
Abstract
A pigtail-type optical receptacle includes a tubular ferrule
having a through-hole extending in an axial direction, an optical
fiber inserted into the through-hole such that part of the optical
fiber extends outside the ferrule, a protective member covering the
part of the optical fiber extending outside the ferrule, a tubular
sleeve mounted on a front end side, outer surface of the ferrule, a
holder tubular having holding the rear end side of the ferrule, and
a tubular housing covering the ferrule and at least a portion of
the sleeve. The ferrule through-hole includes first and second
regions, the second region being disposed rearward of the first
region, and the housing engaging the outer surface of the holder
rearward of the first region.
Inventors: |
TOMINAGA; Kohei;
(KITAKYUSHU-SHI, JP) ; KANEYUKI; Satoshi;
(KITAKYUSHU-SHI, JP) ; KONDO; Sho;
(KITAKYUSHU-SHI, JP) ; AGATSUMA; Hirotsugu;
(KITAKYUSHU-SHI, JP) ; HAKOZAKI; Satoshi;
(KITAKYUSHU-SHI, JP) ; SATO; Hiroki;
(KITAKYUSHU-SHI, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOTO LTD. |
KITAKYUSHU-SHI |
|
JP |
|
|
Family ID: |
1000005210235 |
Appl. No.: |
17/094148 |
Filed: |
November 10, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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16420509 |
May 23, 2019 |
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17094148 |
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16029172 |
Jul 6, 2018 |
10345534 |
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16420509 |
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PCT/JP2017/018866 |
May 19, 2017 |
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16029172 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G02B 6/3837 20130101;
G02B 6/4285 20130101; G02B 6/4292 20130101; G02B 6/3874 20130101;
G02B 6/4262 20130101; G02B 6/3869 20130101 |
International
Class: |
G02B 6/38 20060101
G02B006/38; G02B 6/42 20060101 G02B006/42 |
Foreign Application Data
Date |
Code |
Application Number |
May 20, 2016 |
JP |
2016-101550 |
Feb 3, 2017 |
JP |
2017-018454 |
May 19, 2017 |
JP |
2017-099521 |
May 19, 2017 |
JP |
2017-099522 |
Claims
1. A pigtail-type optical receptacle, comprising: a ferrule having
a tubular configuration and having a through-hole extending in an
axial direction; an optical fiber held by the ferrule in a state of
being inserted into the through-hole, the optical fiber extending
outside the ferrule from a rear end side of the ferrule; a
protective member covering a portion of the optical fiber extending
outside the ferrule; a sleeve having a tubular configuration,
engaging an outer surface of the ferrule, and being mounted on a
front end side of the ferrule; a holder having a tubular
configuration, engaging the outer surface of the ferrule, and
holding the rear end side of the ferrule; and a housing having a
tubular configuration, engaging an outer surface of the holder, and
covering the ferrule and at least a portion of the sleeve, the
through-hole of the ferrule including a first region and a second
region, a width in an orthogonal direction of the through-hole in
the first region corresponding to a width in the orthogonal
direction of the optical fiber, the orthogonal direction being
orthogonal to the axial direction, the second region being disposed
rearward of the first region, the width in the orthogonal direction
of the through-hole in the second region widening toward the rear
end side of the ferrule, the housing engaging the outer surface of
the holder rearward of the first region.
2. The receptacle according to claim 1, wherein the outer surface
of the holder includes: a first outer perimeter portion held by the
housing; and a second outer perimeter portion provided at a front
end portion of the holder, the second outer perimeter portion being
recessed inward from the first outer perimeter portion, and the
first outer perimeter portion is positioned rearward of the first
region.
3. The receptacle according to claim 1, wherein an inner surface of
the housing includes: a first inner perimeter portion engaging the
outer surface of the holder; and a second inner perimeter portion
provided frontward of the first inner perimeter portion, the second
inner perimeter portion widening outward from the first inner
perimeter portion, and the first inner perimeter portion is
positioned rearward of the first region.
4. The receptacle according to claim 3, wherein the second inner
perimeter portion is connected to the first inner perimeter portion
via a tilted surface or a curved surface.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation application of U.S. patent
application Ser. No. 16/420,509, filed May 23, 2019, which is a
continuation application of U.S. patent application Ser. No.
16/029,172, filed July 6, 2018, which is a continuation of
International Application PCT/JP2017/018866, filed on May 19, 2017,
which also claims priority to Japanese Application No. 2016-101550,
filed on May 20, 2016, Japanese Application No. 2017-018454, filed
on Feb. 3, 2017, Japanese Application No. 2017-099521, filed on May
19, 2017, and Japanese Application No. 2017-099522, filed on May
19, 2017. The entire contents of each of the above related
applications are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] Embodiments described herein relate generally to a
pigtail-type optical receptacle.
BACKGROUND OF THE INVENTION
[0003] An optical receptacle is used as a part for optically
connecting an optical fiber connector to an optical element such as
a light receiving element, a light-emitting element, or the like in
an optical module of an optical communication transceiver. For such
an optical receptacle, a pigtail-type optical receptacle also is
known in which the optical fiber is drawn out from a ferrule.
[0004] For example, in JP-A 2012-230275 (Kokai), a pigtail-type
optical receptacle is proposed in which a ferrule that holds an
optical fiber is held by a holder; and the holding force of the
parts such as the ferrule, the holder, etc., is increased by
press-fitting the holder into a case.
[0005] Also, in JP-A 2012-230275 (Kokai), because the rear end
surface of the ferrule is positioned on the rear end side of the
press-fit region of the case, the pressure that is applied to the
rear end portion of the ferrule from the holder is reduced.
Thereby, an undesirable concentration of an external force locally
at one portion of the optical fiber at the rear end portion of the
ferrule due to the inner diameter of the ferrule contracting due to
the press-fitting can be suppressed. Also, the increase of the loss
and the decrease of the strength of the optical fiber due to the
concentration of the external force can be suppressed; and the
reliability of the pigtail-type optical receptacle can be
increased.
[0006] However, compared to a configuration in which the rear end
of the ferrule is disposed in the press-fit region, it is necessary
to set the ferrule and/or the holder to be long in the
configuration in which the rear end surface of the ferrule is
positioned on the rear end side of the press-fit region of the
case. Therefore, for the pigtail-type optical receptacle, it has
been difficult to downsize in the longitudinal direction of the
receptacle main body portion (the portion frontward of the drawn
out optical fiber) including the ferrule, the case, etc.
[0007] Generally, the configurations of optical transceivers are
standardized; and the space of the electrical circuit including the
optical elements and the like is undesirably encroached when the
receptacle main body portion is lengthened. Also, higher speeds are
necessary for optical transceivers as the IP traffic increases; and
the space that is necessary for the electrical circuit is
increasing due to the higher speeds of the modulation rate of the
optical signals emitted from the optical elements, etc.
[0008] Therefore, for the pigtail-type optical receptacle, it is
desirable to be able to downsize without causing a decrease of the
reliability due to the concentration of the local external force in
the optical fiber, etc.
SUMMARY OF THE INVENTION
[0009] According to an embodiment of the invention, a pigtail-type
optical receptacle that includes a ferrule, an optical fiber, a
protective member, a sleeve, a holder, and a housing is provided;
the ferrule has a tubular configuration and has a through-hole
extending in an axial direction; the optical fiber is held by the
ferrule in a state of being inserted into the through-hole and
extends outside the ferrule from a rear end side of the ferrule;
the protective member covers a portion of the optical fiber
extending outside the ferrule; the sleeve has a tubular
configuration, engages an outer surface of the ferrule, and is
mounted on a front end side of the ferrule; the holder has a
tubular configuration, engages the outer surface of the ferrule,
and holds the rear end side of the ferrule; the housing has a
tubular configuration, engages an outer surface of the holder, and
covers the ferrule and at least a portion of the sleeve; the
through-hole of the ferrule includes a first region and a second
region; a width in an orthogonal direction of the through-hole in
the first region corresponds to a width in the orthogonal direction
of the optical fiber; the orthogonal direction is orthogonal to the
axial direction; the second region is disposed rearward of the
first region; the width in the orthogonal direction of the
through-hole in the second region widens toward the rear end side
of the ferrule; and the holder holds a portion of the outer surface
of the ferrule rearward of the first region.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross-sectional view illustrating a pigtail-type
optical receptacle according to a first embodiment;
[0011] FIG. 2A to FIG. 2C are cross-sectional views illustrating
specific examples of the ferrule according to the first
embodiment;
[0012] FIG. 3 is a cross-sectional view illustrating a modification
of the pigtail-type optical receptacle according to the first
embodiment;
[0013] FIG. 4 is a cross-sectional view illustrating a modification
of the pigtail-type optical receptacle according to the first
embodiment;
[0014] FIG. 5 is a cross-sectional view illustrating a pigtail-type
optical receptacle according to a second embodiment;
[0015] FIG. 6 is a cross-sectional view illustrating a modification
of the pigtail-type optical receptacle according to the second
embodiment;
[0016] FIG. 7 is a cross-sectional view illustrating a modification
of the pigtail-type optical receptacle according to the second
embodiment;
[0017] FIG. 8A and FIG. 8B are cross-sectional views illustrating
modifications of the pigtail-type optical receptacle according to
the second embodiment;
[0018] FIG. 9 is a cross-sectional view illustrating a pigtail-type
optical receptacle according to a third embodiment;
[0019] FIG. 10A and FIG. 10B are cross-sectional views illustrating
modifications of the pigtail-type optical receptacle according to
the third embodiment;
[0020] FIG. 11 is a cross-sectional view illustrating a
pigtail-type optical receptacle according to a fourth
embodiment;
[0021] FIG. 12 is a partial cross-sectional view illustrating an
enlarged portion of the pigtail-type optical receptacle according
to the fourth embodiment; and
[0022] FIG. 13A to FIG. 13C are partial cross-sectional views
illustrating modifications of the pigtail-type optical receptacle
according to the fourth embodiment.
DETAILED DESCRIPTION
[0023] A first invention is a pigtail-type optical receptacle that
includes a ferrule, an optical fiber, a protective member, a
sleeve, a holder, and a housing; the ferrule has a tubular
configuration and has a through-hole extending in an axial
direction; the optical fiber is held by the ferrule in a state of
being inserted into the through-hole and extends outside the
ferrule from a rear end side of the ferrule; the protective member
covers a portion of the optical fiber extending outside the
ferrule; the sleeve has a tubular configuration, engages an outer
surface of the ferrule, and is mounted on a front end side of the
ferrule; the holder has a tubular configuration, engages the outer
surface of the ferrule, and holds the rear end side of the ferrule;
the housing has a tubular configuration, engages an outer surface
of the holder, and covers the ferrule and at least a portion of the
sleeve; the through-hole of the ferrule includes a first region and
a second region; a width in an orthogonal direction of the
through-hole in the first region corresponds to a width in the
orthogonal direction of the optical fiber; the orthogonal direction
is orthogonal to the axial direction; the second region is disposed
rearward of the first region; the width in the orthogonal direction
of the through-hole in the second region widens toward the rear end
side of the ferrule; and the holder holds a portion of the outer
surface of the ferrule rearward of the first region.
[0024] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the holder
holds the portion of the outer surface of the ferrule rearward of
the first region. Thereby, for example, even in the case where the
ferrule contracts, an undesirable concentration of an external
force in the optical fiber at the boundary portion between the
first region holding the optical fiber and the second region not
holding the optical fiber can be suppressed. Accordingly, a
pigtail-type optical receptacle that can be downsized without
causing a decrease of the reliability can be provided.
[0025] A second invention is the pigtail-type optical receptacle of
the first invention, wherein a change of the width in the
orthogonal direction of the through-hole in the second region has a
curved configuration. The curved configuration is convex toward a
central axis side of the through-hole.
[0026] According to the pigtail-type optical receptacle, the
undesirable concentration of the external force in the optical
fiber at the boundary portion between the first region and the
second region can be suppressed further.
[0027] A third invention is the pigtail-type optical receptacle of
the second invention, wherein the through-hole of the ferrule
further includes a third region disposed rearward of the second
region; and a change of the width in the orthogonal direction of
the through-hole in the third region has a linear
configuration.
[0028] According to the pigtail-type optical receptacle, the
undesirable concentration of the external force in the optical
fiber at the boundary portion between the first region and the
second region can be suppressed further.
[0029] A fourth invention is the pigtail-type optical receptacle of
the first invention, wherein a front end of the protective member
is positioned inside the second region of the through-hole.
[0030] According to the pigtail-type optical receptacle, the length
of the portion of the optical fiber protruding from the protective
member can be shortened as much as possible. Thereby, for example,
flexing of the optical fiber can be suppressed; and the optical
fiber can be inserted easily into the through-hole of the ferrule.
The manufacturability of the pigtail-type optical receptacle can be
improved.
[0031] A fifth invention is the pigtail-type optical receptacle of
the third invention, wherein a front end of the protective member
is positioned inside the third region of the through-hole.
[0032] According to the pigtail-type optical receptacle, the length
of the portion of the optical fiber protruding from the protective
member can be shortened as much as possible. Thereby, for example,
flexing of the optical fiber can be suppressed; and the optical
fiber can be inserted easily into the through-hole of the ferrule.
The manufacturability of the pigtail-type optical receptacle can be
improved.
[0033] A sixth invention is the pigtail-type optical receptacle of
the first invention, wherein the holder holds the rear end side of
the ferrule by press-fitting.
[0034] According to the pigtail-type optical receptacle, the
ferrule can be held appropriately by a simple configuration.
[0035] A seventh invention is the pigtail-type optical receptacle
of the first invention, wherein a rear end of the holder is
positioned rearward of the rear end of the ferrule; the holder
surrounds a portion of the optical fiber and a portion of the
protective member; and the optical fiber and the protective member
further extend outside the holder and are fixedly bonded to the
holder by an elastic member filled into the through-hole and into
the holder.
[0036] According to the pigtail-type optical receptacle,
deformation and/or tilting due to an external force of the portion
of the optical fiber protruding from the protective member can be
suppressed. Also, the protrusion from or the reverse retraction
into the ferrule of the front end of the optical fiber due to the
application of the external force can be suppressed.
[0037] An eighth invention is the pigtail-type optical receptacle
of the seventh invention, wherein an inner perimeter surface of the
holder includes a first inner perimeter portion and a second inner
perimeter portion; the first inner perimeter portion engages the
outer surface of the ferrule; the second inner perimeter portion is
positioned rearward of the first inner perimeter portion, protrudes
inward from the first inner perimeter portion, and surrounds a
portion of the optical fiber and a portion of the protective
member; a gap in the axial direction is provided between the second
inner perimeter portion and the rear end of the ferrule; and the
elastic member is filled also into the gap.
[0038] According to the pigtail-type optical receptacle, the
deformation and/or the positional shift of the optical fiber front
end portion due to the external force can be suppressed
further.
[0039] A ninth invention is the pigtail-type optical receptacle of
the first invention, wherein the holder has a first rear end
surface and a second rear end surface; and the second rear end
surface is recessed frontward of the first rear end surface on an
outer perimeter side of the first rear end surface.
[0040] According to the pigtail-type optical receptacle, for
example, the first rear end surface can be used as a receiving
surface of the bonding agent (the elastic member) when fixedly
bonding the optical fiber and the protective member; and the second
rear end surface can be used as a positional alignment surface
between the holder and the housing. Thereby, the undesirable
flowing of the bonding agent to the positional alignment surface
and the undesirable occurrence of the positional shift between the
holder and the housing can be suppressed. Also, the protective
member can be fixedly bonded in a longer region by setting the
length of the portion of the first rear end surface to be longer
than the length of the holder necessary to be held by the housing.
Thereby, the deformation and/or the positional shift of the optical
fiber front end portion can be suppressed further.
[0041] A tenth invention is the pigtail-type optical receptacle of
the first invention, wherein the outer surface of the holder
includes a first outer perimeter portion and a second outer
perimeter portion; the first outer perimeter portion is held by the
housing; and the second outer perimeter portion is provided at a
front end portion of the holder and is recessed inward from the
first outer perimeter portion.
[0042] According to the pigtail-type optical receptacle, the
portion where the holder is held by the housing can be shifted
rearward; and the undesirable concentration of the external force
in the optical fiber at the boundary portion between the first
region and the second region can be suppressed further.
[0043] An eleventh invention is the pigtail-type optical receptacle
of the first invention, wherein the holder includes a chamfer
portion between a rear end surface and an inner perimeter
surface.
[0044] According to the pigtail-type optical receptacle, by
providing the chamfer portion, the optical fiber can be inserted
easily into the holder; and the manufacturability can be improved.
Also, the chamfer portion can be used as a bonding agent reservoir
when fixedly bonding the optical fiber and the protective member;
and the undesirable flowing of the bonding agent to the positional
alignment surface can be suppressed further.
[0045] A twelfth invention is the pigtail-type optical receptacle
of the seventh invention, wherein the elastic member includes a
protrusion protruding outside the holder on the rear end side of
the holder and covering a corner portion between the rear end of
the holder and an outer surface of the protective member.
[0046] According to the pigtail-type optical receptacle, the
undesirable bending of the optical fiber locally at the corner
portion between the rear end of the holder and the outer surface of
the protective member when the load is applied by the external
force can be suppressed.
[0047] A thirteenth invention is the pigtail-type optical
receptacle of the first invention, wherein the housing holds the
holder by press-fitting.
[0048] According to the pigtail-type optical receptacle, the holder
can be held appropriately by a simple configuration.
[0049] A fourteenth invention is the pigtail-type optical
receptacle of the first invention, wherein the outer surface of the
ferrule includes a first contact portion contacting an inner
perimeter surface of the holder; the outer surface of the holder
includes a second contact portion contacting an inner perimeter
surface of the housing; and an intermediate point in the axial
direction of the second contact portion is positioned rearward of
an intermediate point in the axial direction of the first contact
portion.
[0050] According to the pigtail-type optical receptacle, for
example, even in the case where the holder is press-fitted into the
housing, etc., the clamping force due to the press-fitting is
dispersed in a wide region by the second contact portion; and the
undesirable concentration of the external force in the optical
fiber at the boundary portion between the first region and the
second region can be suppressed further.
[0051] A fifteenth invention is a pigtail-type optical receptacle
that includes a ferrule, an optical fiber, a protective member, a
sleeve, a holder, and a housing; the ferrule has a tubular
configuration and has a through-hole extending in an axial
direction; the optical fiber is held by the ferrule in a state of
being inserted into the through-hole and extends outside the
ferrule from a rear end side of the ferrule; the protective member
covers a portion of the optical fiber extending outside the
ferrule; the sleeve has a tubular configuration, engages an outer
surface of the ferrule, and is mounted on a front end side of the
ferrule; the holder has a tubular configuration, engages the outer
surface of the ferrule, and holds the rear end side of the ferrule;
the housing has a tubular configuration, engages an outer surface
of the holder, and covers the ferrule and at least a portion of the
sleeve; the through-hole of the ferrule includes a first region and
a second region; a width in an orthogonal direction of the
through-hole in the first region corresponds to a width in the
orthogonal direction of the optical fiber; the orthogonal direction
is orthogonal to the axial direction; the second region is disposed
rearward of the first region; the width in the orthogonal direction
of the through-hole in the second region widens toward the rear end
side of the ferrule; and the width in the orthogonal direction of
the through-hole in the second region changes in a curved
configuration having a proportion of the change increasing toward
the rear end side.
[0052] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the width
in the orthogonal direction of the through-hole in the second
region changes in a curved configuration in which the proportion of
the change increases toward the rear end side. Thereby, for
example, even in the case where the ferrule contracts, an
undesirable concentration of an external force in the optical fiber
at the boundary portion between the first region holding the
optical fiber and the second region not holding the optical fiber
can be suppressed. Accordingly, a pigtail-type optical receptacle
that can be downsized without reducing the reliability can be
provided.
[0053] A sixteenth invention is a pigtail-type optical receptacle
that includes a ferrule, an optical fiber, a protective member, a
sleeve, a holder, and a housing; the ferrule has a tubular
configuration and has a through-hole extending in an axial
direction; the optical fiber is held by the ferrule in a state of
being inserted into the through-hole and extends outside the
ferrule from a rear end side of the ferrule; the protective member
covers a portion of the optical fiber extending outside the
ferrule; the sleeve has a tubular configuration, engages an outer
surface of the ferrule, and is mounted on a front end side of the
ferrule; the holder has a tubular configuration, engages the outer
surface of the ferrule, and holds the rear end side of the ferrule;
the housing has a tubular configuration, engages an outer surface
of the holder, and covers the ferrule and at least a portion of the
sleeve; the through-hole of the ferrule includes a first region and
a second region; a width in an orthogonal direction of the
through-hole in the first region corresponds to a width in the
orthogonal direction of the optical fiber; the orthogonal direction
is orthogonal to the axial direction; the second region is disposed
rearward of the first region; the width in the orthogonal direction
of the through-hole in the second region widens toward the rear end
side of the ferrule; and the housing engages the outer surface of
the holder rearward of the first region.
[0054] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the housing
engages the outer surface of the holder rearward of the first
region. Thereby, for example, the undesirable concentration, in the
optical fiber at the boundary portion between the first region
holding the optical fiber and the second region not holding the
optical fiber, of the external force caused by the housing engaging
the outer surface of the holder can be suppressed. Accordingly, a
pigtail-type optical receptacle that can be downsized without
reducing the reliability can be provided.
[0055] A seventeenth invention is the pigtail-type optical
receptacle of the sixteenth invention, wherein the outer surface of
the holder includes a first outer perimeter portion and a second
outer perimeter portion; the first outer perimeter portion is held
by the housing; the second outer perimeter portion is provided at a
front end portion of the holder and is recessed inward from the
first outer perimeter portion; and the first outer perimeter
portion is positioned rearward of the first region.
[0056] According to the pigtail-type optical receptacle, the
undesirable concentration, in the optical fiber at the boundary
portion between the first region holding the optical fiber and the
second region not holding the optical fiber, of the external force
caused by the housing engaging the outer surface of the holder can
be suppressed.
[0057] An eighteenth invention is the pigtail-type optical
receptacle of the sixteenth invention, wherein an inner surface of
the housing includes a first inner perimeter portion and a second
inner perimeter portion; the first inner perimeter portion engages
the outer surface of the holder; the second inner perimeter portion
is provided frontward of the first inner perimeter portion and
widens outward from the first inner perimeter portion; and the
first inner perimeter portion is positioned rearward of the first
region.
[0058] According to the pigtail-type optical receptacle, the
undesirable concentration, in the optical fiber at the boundary
portion between the first region holding the optical fiber and the
second region not holding the optical fiber, of the external force
caused by the housing engaging the outer surface of the holder can
be suppressed.
[0059] A nineteenth invention is the pigtail-type optical
receptacle of the eighteenth invention, wherein the second inner
perimeter portion is connected to the first inner perimeter portion
via a tilted surface or a curved surface.
[0060] According to the pigtail-type optical receptacle, the
housing can be formed easily even in the case where the first inner
perimeter portion and the second inner perimeter portion are
provided in the inner surface of the housing.
[0061] A twentieth invention is a pigtail-type optical receptacle
that includes a ferrule, an optical fiber, a protective member, a
sleeve, a holder, and a housing; the ferrule has a tubular
configuration and has a through-hole extending in an axial
direction; the optical fiber is held by the ferrule in a state of
being inserted into the through-hole and extends outside the
ferrule from a rear end side of the ferrule; the protective member
covers a portion of the optical fiber extending outside the
ferrule; the sleeve has a tubular configuration, engages an outer
surface of the ferrule, and is mounted on a front end side of the
ferrule; the holder has a tubular configuration, engages the outer
surface of the ferrule, and holds the rear end side of the ferrule;
the housing has a tubular configuration, is mounted to the holder,
and covers the ferrule and at least a portion of the sleeve; the
through-hole of the ferrule includes a first region and a second
region; a width in an orthogonal direction of the through-hole in
the first region corresponds to a width in the orthogonal direction
of the optical fiber; the orthogonal direction is orthogonal to the
axial direction; the second region is disposed rearward of the
first region; the width in the orthogonal direction of the
through-hole in the second region widens toward the rear end side
of the ferrule; the holder includes a flange protruding outward
from the housing and being provided frontward of the second region;
and the housing is mounted to the holder frontward of the
flange.
[0062] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the holder
includes the flange protruding outward from the housing and being
provided frontward of the second region; and the housing is mounted
to the holder frontward of the flange. Thereby, for example, the
undesirable concentration, in the optical fiber at the boundary
portion between the first region holding the optical fiber and the
second region not holding the optical fiber, of the external force
caused by mounting the housing can be suppressed. Accordingly, a
pigtail-type optical receptacle that can be downsized without
reducing the reliability can be provided.
[0063] A twenty-first invention is a pigtail-type optical
receptacle that includes a ferrule, an optical fiber, a protective
member, a sleeve, a holder, a housing, a first elastic member, and
a second elastic member; the ferrule has a tubular configuration
and has a through-hole extending in an axial direction; the optical
fiber is held by the ferrule in a state of being inserted into the
through-hole and extends outside the ferrule from a rear end side
of the ferrule; the protective member covers a portion of the
optical fiber extending outside the ferrule; the sleeve has a
tubular configuration, engages an outer surface of the ferrule, and
is mounted on a front end side of the ferrule; the holder has a
tubular configuration, engages the outer surface of the ferrule,
and holds the rear end side of the ferrule; the housing has a
tubular configuration, engages an outer surface of the holder, and
covers the ferrule and at least a portion of the sleeve; the first
elastic member is filled into the through-hole and into the holder;
the second elastic member covers a corner portion between a rear
end of the holder and an outer surface of the protective member;
the through-hole of the ferrule includes a first region and a
second region; a width in an orthogonal direction of the
through-hole in the first region corresponds to a width in the
orthogonal direction of the optical fiber; the orthogonal direction
is orthogonal to the axial direction; the second region is disposed
rearward of the first region; the width in the orthogonal direction
of the through-hole in the second region widens toward the rear end
side of the ferrule; the holder holds a portion of the outer
surface of the ferrule rearward of the first region; the rear end
of the holder is positioned rearward of the rear end of the
ferrule; the holder surrounds a portion of the optical fiber and a
portion of the protective member; the optical fiber and the
protective member further extend outside the holder and are fixedly
bonded to the holder by the first elastic member; and a hardness of
the second elastic member is lower than a hardness of the first
elastic member.
[0064] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the holder
holds a portion of the outer surface of the ferrule rearward of the
first region. Thereby, for example, even in the case where the
ferrule contracts, an undesirable concentration of an external
force in the optical fiber at the boundary portion between the
first region holding the optical fiber and the second region not
holding the optical fiber can be suppressed. Accordingly, a
pigtail-type optical receptacle that can be downsized without
reducing the reliability can be provided.
[0065] Also, because the optical fiber and the protective member
are fixedly bonded to the holder by the first elastic member, the
deformation and/or tilting due to an external force of the portion
of the optical fiber protruding from the protective member can be
suppressed. Also, the protrusion from or the reverse retraction
into the ferrule of the front end of the optical fiber due to the
application of the external force can be suppressed.
[0066] By providing the second elastic member, the starting point
of the bending when the optical fiber is bent by handling, etc.,
can be distal to the first elastic member. In such a case, by
setting the hardness of the second elastic member to be lower than
the hardness of the first elastic member, the stress that is
applied to the protective member at the boundary with the second
elastic member can be suppressed even when the optical fiber is
bent by handling, etc. Thereby, the damage of the protective member
at the vicinity of the boundary with the first elastic member
and/or the second elastic member, etc., can be suppressed; and the
risk of breakage of the optical fiber can be reduced further.
[0067] A twenty-second invention is a pigtail-type optical
receptacle that includes a ferrule, an optical fiber, a protective
member, a sleeve, a holder, a housing, a first elastic member, and
a second elastic member; the ferrule has a tubular configuration
and has a through-hole extending in an axial direction; the optical
fiber is held by the ferrule in a state of being inserted into the
through-hole and extends outside the ferrule from a rear end side
of the ferrule; the protective member covers a portion of the
optical fiber extending outside the ferrule; the sleeve has a
tubular configuration, engages an outer surface of the ferrule, and
is mounted on a front end side of the ferrule; the holder has a
tubular configuration, engages the outer surface of the ferrule,
and holds the rear end side of the ferrule; the housing has a
tubular configuration, engages an outer surface of the holder, and
covers the ferrule and at least a portion of the sleeve; the first
elastic member is filled into the through-hole and into the holder;
the second elastic member covers a corner portion between a rear
end of the holder and an outer surface of the protective member;
the through-hole of the ferrule includes a first region and a
second region; a width in an orthogonal direction of the
through-hole in the first region corresponds to a width in the
orthogonal direction of the optical fiber; the orthogonal direction
is orthogonal to the axial direction; the second region is disposed
rearward of the first region; the width in the orthogonal direction
of the through-hole in the second region widens toward the rear end
side of the ferrule; the width in the orthogonal direction of the
through-hole in the second region changes in a curved configuration
having a proportion of the change increasing toward the rear end
side; the rear end of the holder is positioned rearward of the rear
end of the ferrule; the holder surrounds a portion of the optical
fiber and a portion of the protective member; the optical fiber and
the protective member further extend outside the holder and are
fixedly bonded to the holder by the first elastic member; and a
hardness of the second elastic member is lower than a hardness of
the first elastic member.
[0068] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the width
in the orthogonal direction of the through-hole in the second
region changes in a curved configuration in which the proportion of
the change increases toward the rear end side. Thereby, for
example, even in the case where the ferrule contracts, an
undesirable concentration of an external force in the optical fiber
at the boundary portion between the first region holding the
optical fiber and the second region not holding the optical fiber
can be suppressed. Accordingly, a pigtail-type optical receptacle
that can be downsized without reducing the reliability can be
provided.
[0069] Also, because the optical fiber and the protective member
are fixedly bonded to the holder by the first elastic member, the
deformation and/or tilting due to an external force of the portion
of the optical fiber protruding from the protective member can be
suppressed. Also, the protrusion from or the reverse retraction
into the ferrule of the front end of the optical fiber due to the
application of the external force can be suppressed.
[0070] Also, by providing the second elastic member, the starting
point of the bending when the optical fiber is bent by the
handling, etc., can be distal to the first elastic member. In such
a case, by setting the hardness of the second elastic member to be
lower than the hardness of the first elastic member, the stress
that is applied to the protective member at the boundary with the
second elastic member when the optical fiber is bent by handling,
etc., can be suppressed. Thereby, the damage of the protective
member at the vicinity of the boundary with the first elastic
member and/or the second elastic member, etc., can be suppressed;
and the risk of breakage of the optical fiber can be reduced
further.
[0071] A twenty-third invention is a pigtail-type optical
receptacle that includes a ferrule, an optical fiber, a protective
member, a sleeve, a holder, a housing, a first elastic member, and
a second elastic member; the ferrule has a tubular configuration
and has a through-hole extending in an axial direction; the optical
fiber is held by the ferrule in a state of being inserted into the
through-hole and extends outside the ferrule from a rear end side
of the ferrule; the protective member covers a portion of the
optical fiber extending outside the ferrule; the sleeve has a
tubular configuration, engages an outer surface of the ferrule, and
is mounted on a front end side of the ferrule; the holder has a
tubular configuration, engages the outer surface of the ferrule,
and holds the rear end side of the ferrule; the housing has a
tubular configuration, engages an outer surface of the holder, and
covers the ferrule and at least a portion of the sleeve; the first
elastic member is filled into the through-hole and into the holder;
the second elastic member covers a corner portion between a rear
end of the holder and an outer surface of the protective member;
the through-hole of the ferrule includes a first region and a
second region; a width in an orthogonal direction of the
through-hole in the first region corresponds to a width in the
orthogonal direction of the optical fiber; the orthogonal direction
is orthogonal to the axial direction; the second region is disposed
rearward of the first region; the width in the orthogonal direction
of the through-hole in the second region widens toward the rear end
side of the ferrule; the housing engages the outer surface of the
holder rearward of the first region; the rear end of the holder is
positioned rearward of the rear end of the ferrule; the holder
surrounds a portion of the optical fiber and a portion of the
protective member; the optical fiber and the protective member
further extend outside the holder and are fixedly bonded to the
holder by the first elastic member; and a hardness of the second
elastic member is lower than a hardness of the first elastic
member.
[0072] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the housing
engages the outer surface of the holder rearward of the first
region. Thereby, for example, the undesirable concentration, in the
optical fiber at the boundary portion between the first region
holding the optical fiber and the second region not holding the
optical fiber, of the external force caused by the housing engaging
the outer surface of the holder can be suppressed. Accordingly, a
pigtail-type optical receptacle that can be downsized without
reducing the reliability can be provided.
[0073] Also, because the optical fiber and the protective member
are fixedly bonded to the holder by the first elastic member, the
deformation and/or tilting due to an external force of the portion
of the optical fiber protruding from the protective member can be
suppressed. Also, the protrusion from or the reverse retraction
into the ferrule of the front end of the optical fiber due to the
application of the external force can be suppressed.
[0074] By providing the second elastic member, the starting point
of the bending when the optical fiber is bent by the handling,
etc., can be distal to the first elastic member. In such a case, by
setting the hardness of the second elastic member to be lower than
the hardness of the first elastic member, the stress that is
applied to the protective member at the boundary with the second
elastic member can be suppressed even when the optical fiber is
bent by handling, etc. Thereby, the damage of the protective member
at the vicinity of the boundary with the first elastic member
and/or the second elastic member, etc., can be suppressed; and the
risk of breakage of the optical fiber can be reduced further.
[0075] A twenty-fourth invention is a pigtail-type optical
receptacle that includes a ferrule, an optical fiber, a protective
member, a sleeve, a holder, a housing, a first elastic member, and
a second elastic member; the ferrule has a tubular configuration
and has a through-hole extending in an axial direction; the optical
fiber is held by the ferrule in a state of being inserted into the
through-hole and extends outside the ferrule from a rear end side
of the ferrule; the protective member covers a portion of the
optical fiber extending outside the ferrule; the sleeve has a
tubular configuration, engages an outer surface of the ferrule, and
is mounted on a front end side of the ferrule; the holder has a
tubular configuration, engages the outer surface of the ferrule,
and holds the rear end side of the ferrule; the housing has a
tubular configuration, is mounted to the holder, and covers the
ferrule and at least a portion of the sleeve; the first elastic
member is filled into the through-hole and into the holder; the
second elastic member covers a corner portion between a rear end of
the holder and an outer surface of the protective member; the
through-hole of the ferrule includes a first region and a second
region; a width in an orthogonal direction of the through-hole in
the first region corresponds to a width in the orthogonal direction
of the optical fiber; the orthogonal direction is orthogonal to the
axial direction; the second region is disposed rearward of the
first region; the width in the orthogonal direction of the
through-hole in the second region widens toward the rear end side
of the ferrule; the holder includes a flange protruding outward
from the housing and being provided frontward of the second region;
the housing is mounted to the holder frontward of the flange; the
rear end of the holder is positioned rearward of the rear end of
the ferrule; the holder surrounds a portion of the optical fiber
and a portion of the protective member; the optical fiber and the
protective member further extend outside the holder and are fixedly
bonded to the holder by the first elastic member; and a hardness of
the second elastic member is lower than a hardness of the first
elastic member.
[0076] According to the pigtail-type optical receptacle, because
the ferrule and at least a portion of the sleeve are housed in the
housing, the lengths of the ferrule and/or the housing can be
shortened compared to a configuration in which the rear end portion
of the ferrule protrudes rearward of the housing. Also, the holder
includes the flange protruding outward from the housing and being
provided frontward of the second region; and the housing is mounted
to the holder frontward of the flange. Thereby, for example, the
undesirable concentration, in the optical fiber at the boundary
portion between the first region holding the optical fiber and the
second region not holding the optical fiber, of the external force
caused by mounting the housing can be suppressed. Accordingly, a
pigtail-type optical receptacle that can be downsized without
reducing the reliability can be provided.
[0077] Also, because the optical fiber and the protective member
are fixedly bonded to the holder by the first elastic member, the
deformation and/or tilting due to an external force of the portion
of the optical fiber protruding from the protective member can be
suppressed. Also, the protrusion from or the reverse retraction
into the ferrule of the front end of the optical fiber due to the
application of the external force can be suppressed.
[0078] Also, by providing the second elastic member, the starting
point of the bending when the optical fiber is bent by the
handling, etc., can be distal to the first elastic member. In such
a case, by setting the hardness of the second elastic member to be
lower than the hardness of the first elastic member, the stress
that is applied to the protective member at the boundary with the
second elastic member can be suppressed even when the optical fiber
is bent by handling, etc. Thereby, the damage of the protective
member at the vicinity of the boundary with the first elastic
member and/or the second elastic member, etc., can be suppressed;
and the risk of breakage of the optical fiber can be reduced
further.
[0079] A twenty-fifth invention is the pigtail-type optical
receptacle of the twenty-first invention, wherein a width of the
second elastic member at a rear end surface of the holder is wider
than a width of the first elastic member at the rear end surface of
the holder.
[0080] According to the pigtail-type optical receptacle, the wall
thickness of the second elastic member can be ensured appropriately
regardless of the final quality of the width of the first elastic
member at the rear end surface of the holder; and the damage of the
second elastic member itself, etc., can be suppressed even when the
optical fiber is bent due to the stress from the outside, etc.
[0081] A twenty-sixth invention is the pigtail-type optical
receptacle of the twenty-first invention, wherein the holder has a
first rear end surface and a second rear end surface; the second
rear end surface is recessed frontward of the first rear end
surface on an outer perimeter side of the first rear end surface;
and a width in a direction orthogonal to the axial direction of the
second elastic member is narrower than a width in the direction
orthogonal to the axial direction of the first rear end
surface.
[0082] According to the pigtail-type optical receptacle, for
example, the first rear end surface can be used as a receiving
surface of the bonding agent (the elastic member) when fixedly
bonding the optical fiber and the protective member; and the second
rear end surface can be used as a positional alignment surface
between the holder and the housing. Thereby, the undesirable
flowing of the bonding agent to the positional alignment surface
and the undesirable occurrence of the positional shift between the
holder and the housing can be suppressed. Also, the protective
member can be fixedly bonded in a longer region by setting the
length of the portion of the first rear end surface to be longer
than the length of the holder necessary to be held by the housing.
Thereby, the deformation and/or the positional shift of the optical
fiber front end portion can be suppressed further.
[0083] Also, the flowing of the second elastic member to the second
rear end surface can be suppressed; and the appropriate positional
alignment when assembling is possible.
[0084] A twenty-seventh invention is the pigtail-type optical
receptacle of the twenty-first invention, wherein the first elastic
member includes a protrusion protruding outside the holder on the
rear end side of the holder; the protrusion covers a corner portion
between the rear end of the holder and the outer surface of the
protective member; and the second elastic member covers the
protrusion.
[0085] According to the pigtail-type optical receptacle, the
undesirable bending of the optical fiber locally at the corner
portion between the rear end of the holder and the outer surface of
the protective member when the load is applied by the external
force can be suppressed.
[0086] A twenty-eighth invention is the pigtail-type optical
receptacle of the twenty-seventh invention, wherein a length in the
axial direction of the second elastic member is longer than a
length in the axial direction of the protrusion.
[0087] According to the pigtail-type optical receptacle, the wall
thickness of the second elastic member can be ensured appropriately
regardless of the final quality of the length in the axial
direction of the protrusion; and the damage of the second elastic
member itself, etc., can be suppressed even when the optical fiber
is bent due to the stress from the outside, etc.
[0088] A twenty-ninth invention is the pigtail-type optical
receptacle of the twenty-seventh invention, wherein an average tilt
angle between an outer surface of the second elastic member and a
rear end surface of the holder is not less than an average tilt
angle between an outer surface of the protrusion and the rear end
surface of the holder.
[0089] According to the pigtail-type optical receptacle, the wall
thickness of the second elastic member can be ensured appropriately
regardless of the final quality of the width of the first elastic
member at the rear end surface of the holder; and the damage of the
second elastic member itself, etc., can be suppressed even when the
optical fiber is bent due to the stress from the outside, etc.
[0090] Embodiments of the invention will now be illustrated with
reference to the drawings. Similar components in the drawings are
marked with the same reference numerals; and a detailed description
is omitted as appropriate.
First Embodiment
[0091] FIG. 1 is a cross-sectional view illustrating a pigtail-type
optical receptacle according to a first embodiment.
[0092] As illustrated in FIG. 1, the pigtail-type optical
receptacle (hereinbelow, called the optical receptacle) 10 includes
a ferrule 12, an optical fiber 14, a protective member 16, a sleeve
18, a holder 20, and a housing 22.
[0093] The ferrule 12 has a tubular configuration that has a
through-hole 12t extending in the axial direction. The through-hole
12t pierces in a linear configuration between a front end 12a and a
rear end 12b of the ferrule 12. The optical fiber 14 is held by the
ferrule 12 in a state of being inserted into the through-hole 12t,
and extends outside the ferrule 12 from the rear end 12b side of
the ferrule 12. In other words, the ferrule 12 holds one end
portion of the optical fiber 14.
[0094] The optical fiber 14 is inserted into substantially the
entire through-hole 12t. A front end 14a of the optical fiber 14 is
substantially coplanar with the front end 12a of the ferrule 12.
The front end 12a of the ferrule 12 and the front end 14a of the
optical fiber 14 form the PC (Physical Contact) surface for a plug
ferrule (not illustrated) that is inserted into the optical
receptacle 10. The optical fiber 14 is connected optically to the
plug ferrule inserted into the optical receptacle 10. In the
example, the front ends 12a and 14a are polished into planar
configurations. For example, the front ends 12a and 14a may be
polished into convex spherical configurations, etc.
[0095] For example, the end portion of the optical fiber 14 on the
side opposite to the ferrule 12 is connected optically to an
optical element such as a semiconductor laser element or the like
via an optical connector or the like. Thereby, the optical
receptacle 10 optically connects the optical element to the
inserted plug ferrule via the optical fiber 14.
[0096] For example, the ferrule 12 has a cylindrical configuration.
For example, the cross section of the optical fiber 14 is a
substantially circular fine wire configuration. The through-hole
12t is formed to correspond to the cross-sectional configuration of
the optical fiber 14. In other words, the cross-sectional
configuration of the through-hole 12t is substantially circular.
More specifically, the "cross section" here is a cross section
orthogonal to the axial direction of the ferrule 12 having the
tubular configuration. The exterior configuration of the ferrule 12
in the cross section orthogonal to the axial direction is not
limited to a circle and may be a polygon, etc.
[0097] For example, the ferrule 12 includes a ceramic, glass, etc.
More favorably, a zirconia ceramic is used. The optical fiber 14
includes, for example, a core that extends along the axial
direction, and cladding that surrounds the periphery of the core.
The refractive index of the core is higher than the refractive
index of the cladding. The core and the cladding of the optical
fiber 14 include, for example, quartz glass. An impurity may be
added to the quartz glass. Also, the optical fiber 14 is flexible
and can be flexed in any direction.
[0098] The protective member 16 covers the portion of the optical
fiber 14 extending outside the ferrule 12. The protective member 16
is flexible and flexes in any direction with the optical fiber 14.
The protective member 16 includes, for example, a resin material
such as a polyester elastomer, an acrylate resin, etc. The outer
diameter of the protective member 16 is, for example, about 0.2 mm
to 0.5 mm. The lengths of the portions of the optical fiber 14 and
the protective member 16 extending outside the ferrule 12 are, for
example, about 80 mm. The lengths of the portions of the optical
fiber 14 and the protective member 16 extending outside the ferrule
12 are not limited thereto and may be any length.
[0099] The sleeve 18 engages an outer surface 12g of the ferrule 12
and is mounted on the front end 12a side of the ferrule 12. A front
end 18a of the sleeve 18 protrudes frontward of the front end 12a
of the ferrule 12. The sleeve 18 surrounds the front end 12a of the
ferrule 12 and the front end 14a of the optical fiber 14 around the
axes. The sleeve 18 holds the plug ferrule inserted from the front
end side and allows the optical connection between the optical
fiber 14 and the plug ferrule.
[0100] For example, the sleeve 18 has a cylindrical configuration.
The inner diameter of the sleeve 18 is substantially the same as
the outer diameter of the ferrule 12. Thereby, the sleeve 18
engages the outer surface 12g of the ferrule 12. The
cross-sectional configuration of the sleeve 18 corresponds to the
cross-sectional configuration of the ferrule 12. For example, in
the case where the exterior configuration of the ferrule 12 is a
quadrilateral, the sleeve 18 is formed in a quadrilateral tubular
configuration.
[0101] Also, the sleeve 18 has a slit extending in the axial
direction. More specifically, the cross-sectional configuration of
the sleeve 18 is a substantially C-shaped configuration. The sleeve
18 is a so-called split sleeve. The slit is provided as necessary
and is omissible. The sleeve 18 may have a tubular configuration
that is continuous in a ring configuration around the axis.
[0102] The sleeve 18 includes, for example, a resin material, a
metal material, a ceramic, etc. More favorably, a zirconia ceramic
is used.
[0103] The holder 20 engages the outer surface 12g of the ferrule
12 and holds the rear end 12b side of the ferrule 12. For example,
the holder 20 has a cylindrical configuration. Similarly to the
sleeve 18, the cross-sectional configuration of the holder 20
corresponds to the cross-sectional configuration of the ferrule 12.
The holder 20 may be a tube having any cross-sectional
configuration corresponding to the ferrule 12. The holder 20
includes, for example, a metal material such as stainless steel,
etc. The material of the holder 20 may be a resin material, a
ceramic, etc.
[0104] The housing 22 engages an outer surface 20g of the holder 20
and covers the ferrule 12 and the sleeve 18. The housing 22 covers
the ferrule 12 and the sleeve 18 around the axes and protects the
ferrule 12 and the sleeve 18 from external forces, etc. Thus, the
holder 20 holds the ferrule 12 and the sleeve 18 in a state of
being housed inside the housing 22. For example, the housing 22 has
a cylindrical configuration. The outer diameter of the holder 20 is
larger than the outer diameter of the sleeve 18. The inner diameter
of the housing 22 is substantially the same as the outer diameter
of the holder 20. The housing 22 engages only the outer surface 20g
of the holder 20 without engaging the outer surface of the sleeve
18.
[0105] The housing 22 may be a tube having any cross-sectional
configuration corresponding to the holder 20. Also, in the example,
the housing 22 covers substantially the entire outer surface of the
sleeve 18. In other words, the entire sleeve 18 is housed inside
the housing 22. This is not limited thereto; for example, a portion
of the sleeve 18 may protrude frontward of the housing 22. It is
sufficient for the housing 22 to cover at least a portion of the
sleeve 18. The housing 22 includes, for example, a metal material
such as stainless steel, etc. The material of the housing 22 may be
a resin material, a ceramic, etc.
[0106] The through-hole 12t of the ferrule 12 includes a first
region R1 and a second region R2. The first region R1 is a region
where the width in an orthogonal direction orthogonal to the axial
direction corresponds to the width in the orthogonal direction of
the optical fiber 14. In other words, the first region R1 is a
portion of the through-hole 12t having substantially the same
diameter as the outer diameter of the optical fiber 14. The
diameter of the first region R1 is substantially constant along the
axial direction. Also, the first region R1 is continuous with the
front end 12a of the ferrule 12. The ferrule 12 holds the optical
fiber 14 in the first region R1.
[0107] The second region R2 is disposed rearward of the first
region R1. The second region R2 is continuous with the first region
R1. Also, in the example, the second region R2 is continuous with
the rear end 12b of the ferrule 12. The second region R2 is a
region where the width in the orthogonal direction widens toward
the rear end 12b side of the ferrule 12. In other words, the second
region R2 is a portion of the through-hole 12t in which the
diameter widens toward the rear end 12b side.
[0108] In the second region R2, for example, the diameter widens
continuously toward the rear end 12b side. For example, the
diameter in the second region R2 may widen in stages toward the
rear end 12b side. However, by setting the diameter of the second
region R2 to widen continuously, for example, the front end 14a of
the optical fiber 14 can be inserted easily into the through-hole
12t along the tilt of the second region R2 when inserting the
optical fiber 14 into the through-hole 12t. For example, the
manufacturability of the optical receptacle 10 can be improved.
[0109] The holder 20 holds only the portion of the outer surface
12g of the ferrule 12 rearward of the first region R1. In the
example, the holder 20 holds only the portion of the outer surface
12g of the ferrule 12 opposing the second region R2.
[0110] A front end 16a of the protective member 16 is positioned
inside the second region R2 of the through-hole 12t. The protective
member 16 covers the portion of the optical fiber 14 not held with
the ferrule 12.
[0111] For example, the holder 20 holds the rear end 12b side of
the ferrule 12 by press-fitting. The ferrule 12 is fixed by
press-fitting into the holder 20. For example, the housing 22 holds
the holder 20 by press-fitting. The holder 20 is fixed by
press-fitting into the housing 22. The holding of the ferrule 12 by
the holder 20 and the holding of the holder 20 by the housing 22
are not limited to press-fitting and may be bonding, etc. However,
by fixing each member by press-fitting as recited above, the
holding force can be increased compared to the case of fixedly
bonding, etc. The members can be held appropriately by a simple
configuration. The minimum length in the axial direction necessary
to fix the ferrule 12 in the holder 20 by press-fitting is, for
example, about 0.3 mm to 0.5 mm. However, further shortening is
possible by increasing the clamping force by adjusting the outer
diameter of the ferrule 12 and the inner diameter of the holder
20.
[0112] A rear end 20b of the holder 20 is positioned rearward of
the rear end 12b of the ferrule 12. The holder 20 surrounds a
portion of the optical fiber 14 and a portion of the protective
member 16 around the axes. The optical fiber 14 and the protective
member 16 further extend outside the holder 20. In other words, the
optical fiber 14 and the protective member 16 are drawn out
rearward from the rear end 20b of the holder 20 in the state of
being inserted through the holder 20 and the ferrule 12 having the
tubular configurations.
[0113] The optical receptacle 10 further includes an elastic member
24 (a first elastic member). The elastic member 24 is filled into
the through-hole 12t of the ferrule 12 and into the holder 20. The
elastic member 24 fixedly bonds the optical fiber 14 and the
protective member 16 to the ferrule 12 and the holder 20. The
elastic member 24 includes, for example, a resin material such as
an epoxy resin, etc. The elastic member 24 is, for example, a cured
bonding agent.
[0114] It is sufficient for the elastic member 24 to enter at least
a portion of the interior of the through-hole 12t and at least a
portion of the interior of the holder 20. The entireties of the
interiors of the through-hole 12t and the holder 20 may not be
always be filled with the elastic member 24. For example, "filling"
also includes the case where a void or the like is partially
included.
[0115] An inner perimeter surface 20n of the holder 20 includes a
first inner perimeter portion IS1 and a second inner perimeter
portion IS2. The first inner perimeter portion IS1 engages the
outer surface 12g of the ferrule 12. The second inner perimeter
portion IS2 is positioned rearward of the first inner perimeter
portion IS1, protrudes inward from the first inner perimeter
portion IS1, and surrounds a portion of the optical fiber 14 and a
portion of the protective member 16 around the axes.
[0116] The inner diameter of the portion of the first inner
perimeter portion IS1 of the holder 20 is substantially the same as
the outer diameter of the ferrule 12. On the other hand, the inner
diameter of the portion of the second inner perimeter portion IS2
of the holder 20 is smaller than the outer diameter of the ferrule
12. Accordingly, the second inner perimeter portion IS2 is
positioned rearward of the rear end 12b of the ferrule 12.
[0117] For example, the inner diameter of the portion of the second
inner perimeter portion IS2 is set to a value that is larger than
the outer diameter of the protective member 16 and smaller than the
outer diameter of the ferrule 12. For example, the inner diameter
of the portion of the second inner perimeter portion IS2 is smaller
than the opening diameter on the rear end 12b side of the
through-hole 12t that widens in the second region R2.
[0118] A gap SP in the axial direction is provided between the rear
end 12b of the ferrule 12 and the second inner perimeter portion
IS2. The elastic member 24 is filled also into the gap SP. For
example, the distance in the axial direction of the gap SP is
longer than the outer diameter of the optical fiber 14. For
example, the distance in the axial direction of the gap SP is not
less than about 0.125 mm and not more than about 0.2 mm. In other
words, the distance in the axial direction of the gap SP is the
distance in the axial direction between the second inner perimeter
portion IS2 and the rear end 12b of the ferrule 12. In other words,
the outer diameter of the optical fiber 14 is the length in a
direction orthogonal to the axial direction of the optical fiber
14.
[0119] The holder 20 has a first rear end surface BS1 and a second
rear end surface BS2. The second rear end surface BS2 is recessed
frontward of the first rear end surface BS1 on the outer perimeter
side of the first rear end surface BS1. In the example, the rear
end 20b of the holder 20 is the first rear end surface BS1. For
example, the first rear end surface BS1 has a ring configuration
surrounding the opening end on the rear end 20b side of the holder
20 having the tubular configuration. For example, the second rear
end surface BS2 has a ring configuration surrounding the first rear
end surface BS1 in the state in which the holder 20 is viewed along
the axial direction. The first rear end surface BS1 and the second
rear end surface BS2 are, for example, planes orthogonal to the
axial direction. As described above, the inner perimeter surface
20n of the holder 20 protrudes on the inner side at the rear end
vicinity of the inner perimeter surface 20n. Thereby, the surface
areas of the first rear end surface BS1 and the second rear end
surface BS2 can be increased.
[0120] The holder 20 includes a chamfer portion 20c between the
first rear end surface BS1 (the rear end surface) and the second
inner perimeter portion IS2 (the inner perimeter surface 20n). In
other words, the diameter of the opening on the rear end 20b side
of the holder 20 widens toward the rear end 20b side. The chamfer
portion 20c may be a so-called C-surface in which the corner
between the first rear end surface BS1 and the second inner
perimeter portion IS2 is polished into a linear configuration, or a
so-called R-surface in which the corner between the first rear end
surface BS1 and the second inner perimeter portion IS2 is
rounded.
[0121] The elastic member 24 includes a protrusion 24p that
protrudes outside the holder 20 on the rear end 20b side of the
holder 20 and covers the corner portion between the rear end 20b of
the holder 20 and the outer surface of the protective member 16.
For example, the outer surface of the protrusion 24p is concave
toward the corner portion side and has a concave curved-surface
configuration smoothly connecting the rear end 20b of the holder 20
and the outer surface of the protective member 16.
[0122] The outer surface 12g of the ferrule 12 includes a first
contact portion CP1 contacting the inner perimeter surface 20n of
the holder 20. The outer surface 20g of the holder 20 includes a
second contact portion CP2 contacting the inner perimeter surface
of the housing 22. An intermediate point m2 in the axial direction
of the second contact portion CP2 is positioned rearward of an
intermediate point m1 in the axial direction of the first contact
portion CP1.
[0123] In the optical receptacle 10 according to the embodiment as
described above, because the ferrule 12 and at least a portion of
the sleeve 18 are housed inside the housing 22, the lengths of the
ferrule 12 and/or the housing 22 can be shortened compared to a
configuration in which the rear end 12b of the ferrule 12 protrudes
rearward of the housing 22. Also, the holder 20 holds the portion
of the outer surface 12g of the ferrule 12 rearward of the first
region R1. Thereby, for example, an undesirable concentration of an
external force in the optical fiber 14 at the boundary portion
between the first region R1 holding the optical fiber 14 and the
second region R2 not holding the optical fiber 14 can be suppressed
even in the case where the diameter of the ferrule 12 contracts due
to the press-fitting of the holder 20 into the housing 22 and the
press-fitting of the ferrule 12 into the holder 20. Accordingly,
the optical receptacle 10 in which downsizing is possible can be
provided without causing the decrease of the reliability.
[0124] Also, in the optical receptacle 10, the front end 16a of the
protective member 16 is positioned inside the second region R2 of
the through-hole 12t. Thereby, the length of the portion of the
optical fiber 14 protruding from the protective member 16 can be
shortened as much as possible. For example, the flexing of the
optical fiber 14 can be suppressed; and the optical fiber 14 can be
inserted easily into the through-hole 12t of the ferrule 12. For
example, the manufacturability of the optical receptacle 10 can be
improved.
[0125] In the optical receptacle 10, the holder 20 holds the rear
end 12b side of the ferrule 12 by press-fitting. Thereby, the
holding force can be increased; and the ferrule 12 can be held
appropriately by a simple configuration. In the optical receptacle
10, the optical fiber 14 and the protective member 16 further
extend outside the holder 20 and are fixedly bonded to the holder
20 by the elastic member 24. Thereby, deformation and/or tilting
due to an external force of the portion of the optical fiber 14
protruding from the protective member 16 can be suppressed. Also,
the protrusion from or the reverse retraction into the front end
12a of the ferrule 12 of the front end 14a of the optical fiber 14
due to the application of the external force can be suppressed.
[0126] In the optical receptacle 10, the elastic member 24 is
filled also into the gap SP between the second inner perimeter
portion IS2 and the rear end 12b of the ferrule 12. Thereby, the
deformation and/or the positional shift of the front end portion of
the optical fiber 14 due to the external force can be suppressed
further.
[0127] In the optical receptacle 10, the holder 20 has the first
rear end surface BS1 and the second rear end surface BS2. Thereby,
for example, by using the first rear end surface BS1 as the
receiving surface of the bonding agent used to form the elastic
member 24, the undesirable flowing of the bonding agent to the
second rear end surface BS2 can be suppressed. Then, the
undesirable occurrence of positional shift between the holder 20
and the housing 22 can be suppressed by using the second rear end
surface BS2 as the positional alignment surface when press-fitting
the holder 20 into the housing 22 and by press-fitting into the
housing 22 by pressing the second rear end surface BS2.
[0128] For example, in the case where the coating of the bonding
agent and the positional alignment of the holder 20 are to be
performed in the same plane, there is a possibility that the
bonding agent may undesirably flow to the positional alignment
surface; and the holder 20 may be undesirably press-fitted deeply
into the housing 22 due to the amount of the cured bonding agent.
By providing the first rear end surface BS1 and the second rear end
surface BS2, such positional shift can be suppressed; and the
positional precision between the holder 20 and the housing 22 can
be increased.
[0129] Also, by providing the gap SP, the distance between the
second rear end surface BS2 which is the positional alignment
surface and the front end 12a of the ferrule 12 which is the
PC-surface can be determined more accurately. For example, in the
case where there is no gap SP and the second inner perimeter
portion IS2 and the rear end 12b of the ferrule 12 contact each
other, the length from the second rear end surface BS2 to the front
end 12a of the ferrule 12 undesirably changes due to the final
quality (the error, the fluctuation, etc.) of the total length
dimension of the ferrule 12 and/or the thickness dimension of the
holder 20. Conversely, by providing the gap SP as in the optical
receptacle 10, the length from the second rear end surface BS2 to
the front end 12a of the ferrule 12 can be determined more
accurately without being dependent on the final quality of the
parts. Thereby, an increase of the reliability and/or the
productivity of the optical receptacle 10 can be realized.
[0130] In the case where the gap SP is not provided, there is a
risk that the ferrule 12 may be fixed obliquely due to the final
quality of the perpendicularity of the second inner perimeter
portion IS2 and/or the rear end 12b of the ferrule 12, etc.; the
ferrule 12 may be chipped; and the holder 20 may undesirably
deform. By providing the gap SP in the optical receptacle 10, the
oblique press-fitting of the ferrule 12, the damage and deformation
of the parts, etc., can be suppressed regardless of the final
quality of the parts.
[0131] The error of the total length dimension of the ferrule 12
is, for example, about .+-.0.05 mm (a range of 0.1 mm). The error
of the thickness dimension of the holder 20 is, for example, about
.+-.0.05 mm (a range of 0.1 mm). In such a case, it is favorable
for the distance in the axial direction of the gap SP to be about
0.2 mm. Thus, the distance in the axial direction of the gap SP is
set to be longer than the outer diameter of the optical fiber 14.
The distance in the axial direction of the gap SP is set to be not
less than about 0.125 mm and not more than about 0.2 mm. Thereby,
the reliability and/or the productivity of the optical receptacle
10 can be increased further.
[0132] Also, the length where the protective member 16 is fixedly
bonded can be longer by setting the length of the portion of the
first rear end surface BS1 to be longer than the length necessary
for the holder 20 to be held by the housing 22 (the length
necessary for the press-fitting). Thereby, the deformation and/or
the positional shift of the front end portion of the optical fiber
14 can be suppressed further.
[0133] In the optical receptacle 10, by providing the chamfer
portion 20c between the rear end surface and the inner perimeter
surface of the holder 20, the optical fiber 14 can be inserted
easily into the holder 20; and the manufacturability can be
improved. Also, when coating a bonding agent on the first rear end
surface BS1, the chamfer portion 20c can be used as a bonding agent
reservoir; and the undesirable flowing of the bonding agent to the
second rear end surface BS2 (the positional alignment surface) can
be suppressed further.
[0134] In the optical receptacle 10, the elastic member 24 includes
the protrusion 24p. Thereby, the undesirable bending of the optical
fiber 14 locally at the corner portion between the rear end 20b of
the holder 20 and the outer surface of the protective member 16
when the load is applied by the external force can be suppressed.
For example, the starting point of the bending of the optical fiber
14 can be distal to the boundary portion between the first region
R1 and the second region R2.
[0135] In the optical receptacle 10, the housing 22 holds the
holder 20 by press-fitting. Thereby, the holding force can be
increased; and the holder 20 can be held appropriately by a simple
configuration.
[0136] In the optical receptacle 10, the intermediate point m2 of
the second contact portion CP2 of the holder 20 is positioned
rearward of the intermediate point m1 of the first contact portion
CP1 of the ferrule 12. Thereby, for example, even in the case where
the holder 20 is press-fitted into the housing 22, etc., the
clamping force due to the press-fitting can be dispersed over a
wide region by the second contact portion CP2; and the undesirable
concentration of the external force in the optical fiber 14 at the
boundary portion between the first region R1 and the second region
R2 can be suppressed further.
[0137] FIG. 2A to FIG. 2C are cross-sectional views illustrating
specific examples of the ferrule according to the first
embodiment.
[0138] In the example as illustrated in FIG. 2A, the change of the
diameter (the width in the orthogonal direction) of the
through-hole 12t in the second region R2 has a linear
configuration. The inner perimeter surface of the second region R2
of the through-hole 12t has a linear configuration in a cross
section parallel to the central axis of the through-hole 12t (the
cross section illustrated in FIG. 2A). Thus, the change of the
diameter in the second region R2 has, for example, a linear
configuration. A spread angle .theta. of the diameter of the
through-hole 12t in the second region R2 is, for example, not less
than 60.degree. and not more than 90.degree.. For example, the
spread angle .theta. is set to 60.degree.; and in the case where
the diameter of the through-hole 12t in the first region R1 is set
to 0.8 mm, the length in the axial direction of the second region
R2 is about 0.6 mm.
[0139] In such a case, when the inner diameter of the ferrule 12
contracts due to the press-fitting, etc., stress is applied to the
portion of the optical fiber 14 inserted into the through-hole 12t
in the first region R1; but the stress due to the contraction
substantially is not applied to the portion in the second region
R2. Therefore, the difference between the stresses applied to the
optical fiber 14 at the boundary portion between the first region
R1 and the second region R2 is large.
[0140] Accordingly, in the case where the ferrule 12 illustrated in
FIG. 2A is used, as recited above, the holder 20 is set to hold the
portion of the outer surface 12g of the ferrule 12 rearward of the
first region R1. Thereby, the contraction of the diameter at the
portion in the first region R1 can be suppressed; and the stress
difference that is generated at the boundary portion between the
first region R1 and the second region R2 can be relaxed. The
undesirable concentration of the external force in the optical
fiber 14 at the boundary portion between the first region R1 and
the second region R2 can be suppressed.
[0141] In the example as illustrated in FIG. 2B, the change of the
diameter of the through-hole 12t in the second region R2 has a
curved configuration that is convex toward the central axis side of
the through-hole 12t. The inner perimeter surface of the second
region R2 of the through-hole 12t has a convex curved configuration
in a cross section parallel to the central axis of the through-hole
12t. For example, the inner perimeter surface of the second region
R2 of the through-hole 12t smoothly connects the inner perimeter
surface of the first region R1 of the through-hole 12t and the rear
end surface of the ferrule 12. Thus, for example, the change of the
diameter in the second region R2 may have a convex curved
configuration.
[0142] In such a case, the stress that is applied to the optical
fiber 14 due to the contraction of the inner diameter of the
ferrule 12 changes gradually according to the curved surface of the
inner perimeter surface of the second region R2. In other words, an
abrupt change of the stress applied to the optical fiber 14 at the
boundary portion between the first region R1 and the second region
R2 can be suppressed; and the stress difference at the boundary
portion between the first region R1 and the second region R2 can be
relaxed. Accordingly, the undesirable concentration of the external
force in the optical fiber 14 at the boundary portion between the
first region R1 and the second region R2 can be suppressed
further.
[0143] In the example as illustrated in FIG. 2C, the through-hole
12t of the ferrule 12 further includes a third region R3 disposed
rearward of the second region R2. The third region R3 is continuous
with the second region R2. Also, in the example, the third region
R3 is continuous with the rear end 12b of the ferrule 12.
[0144] Similarly to the example of FIG. 2B, the change of the
diameter of the through-hole 12t in the second region R2 has a
curved configuration that is convex toward the central axis side of
the through-hole 12t. On the other hand, the change of the diameter
of the through-hole 12t in the third region R3 has a linear
configuration. In the third region R3, the diameter of the
through-hole 12t increases continuously in a linear configuration
toward the rear end 12b side. In other words, in the example, the
configuration of the second region R2 is a configuration in which
the intersection portion between the first region R1 and the third
region R3 having the linear configurations is rounded.
[0145] Thus, in the through-hole 12t, the third region R3 where the
diameter changes in the linear configuration may be further
provided rearward of the second region R2 where the diameter
changes in the convex curved configuration. Even in such a case,
similarly to the example of FIG. 2B, the abrupt change of the
stress applied to the optical fiber 14 at the boundary portion
between the first region R1 and the second region R2 can be
suppressed; and the stress difference at the boundary portion
between the first region R1 and the second region R2 can be
relaxed. The undesirable concentration of the external force in the
optical fiber 14 at the boundary portion between the first region
R1 and the second region R2 can be suppressed further. It is
sufficient for a region where the diameter changes in a convex
curved configuration to be provided at least directly after the
first region R1. Also, in the case where the third region R3 is
provided, the front end 16a of the protective member 16 may be
positioned inside the third region R3 of the through-hole 12t. Even
in such a case, similarly to the case where the front end 16a is
positioned in the second region R2, the length of the portion of
the optical fiber 14 protruding from the protective member 16 can
be shortened as much as possible. The flexing of the optical fiber
14 can be suppressed; and the optical fiber 14 can be inserted
easily into the through-hole 12t of the ferrule 12. The
manufacturability of the optical receptacle 10 can be improved.
[0146] In the case where the ferrule 12 includes a ceramic, the
configurations of the through-holes 12t of the examples illustrated
in FIG. 2A to FIG. 2C can be formed by, for example, inserting
pin-shaped molds corresponding to the configurations of the
through-holes 12t into block-shaped ceramics before firing.
[0147] FIG. 3 is a cross-sectional view illustrating a modification
of the pigtail-type optical receptacle according to the first
embodiment.
[0148] In the optical receptacle 10a as illustrated in FIG. 3, the
holder 20 holds the portion of the outer surface 12g of the ferrule
12 rearward of the first region R1 and further holds a portion of
the outer surface 12g opposing the first region R1. Components that
are substantially the same functionally and configurationally as
those of the embodiment recited above are marked with the same
reference numerals; and a detailed description is omitted.
[0149] For example, as illustrated in FIG. 2B and FIG. 2C, in the
case where the change of the diameter of the through-hole 12t in
the second region R2 has a convex curved configuration, the stress
difference at the boundary portion between the first region R1 and
the second region R2 can be relaxed appropriately even by only the
configuration of the through-hole 12t. Accordingly, in such a case,
the holder 20 may further hold the portion opposing the first
region R1. In the optical receptacle 10a as well, downsizing is
possible without causing the decrease of the reliability. However,
the ferrule 12 in which the diameter of the through-hole 12t
changes in the convex curved configuration may be used; and only
the portion of the ferrule 12 rearward of the first region R1 may
be held by the holder 20. Thereby, the stress difference at the
boundary portion between the first region R1 and the second region
R2 can be relaxed more appropriately. The undesirable concentration
of the external force in the optical fiber 14 at the boundary
portion between the first region R1 and the second region R2 can be
suppressed further.
[0150] FIG. 4 is a cross-sectional view illustrating a modification
of the pigtail-type optical receptacle according to the first
embodiment.
[0151] In the optical receptacle 10b as illustrated in FIG. 4, a
rear end 22b of the housing 22 is positioned rearward of the rear
end 20b of the holder 20 and the protrusion 24p of the elastic
member 24. In other words, in the optical receptacle 10b, the
housing 22 further covers the holder 20 around the axis and further
covers the protrusion 24p of the elastic member 24 around the
axis.
[0152] In the optical receptacle 10b, for example, the protrusion
24p of the elastic member 24 can be protected by the housing 22.
The application of an external force to the protrusion 24p can be
suppressed. The concentration of the external force at the boundary
portion between the first region R1 and the second region R2 of the
optical fiber 14 can be suppressed further. The optical fiber 14
can be protected more appropriately from the external force,
etc.
Second Embodiment
[0153] FIG. 5 is a cross-sectional view illustrating a pigtail-type
optical receptacle according to a second embodiment.
[0154] In the optical receptacle 100 as illustrated in FIG. 5, an
outer surface 120g of a holder 120 includes a first outer perimeter
portion OS1 and a second outer perimeter portion OS2.
[0155] The first outer perimeter portion OS1 is held by the housing
22. The outer diameter of the first outer perimeter portion OS1 of
the holder 120 is substantially the same as the inner diameter of
the housing 22. For example, the holder 120 is held by the housing
22 by press-fitting the portion of the first outer perimeter
portion OS1 into the housing 22.
[0156] The second outer perimeter portion OS2 is provided at the
front end portion of the holder 120. For example, the second outer
perimeter portion OS2 is provided frontward of the first outer
perimeter portion OS1, is continuous with the first outer perimeter
portion OS1, and is continuous with a front end 120a of the holder
120. The second outer perimeter portion OS2 is recessed inward from
the first outer perimeter portion OS1. The outer diameter of the
second outer perimeter portion OS2 of the holder 120 is smaller
than the outer diameter of the first outer perimeter portion OS1.
The first outer perimeter portion OS1 is positioned rearward of the
first region R1. Accordingly, the housing 22 engages the outer
surface 120g of the holder 120 rearward of the first region R1.
[0157] Thus, in the optical receptacle 100, by setting the outer
diameter of the front end portion of the holder 120 to be small,
the portion of the holder 120 held by the housing 22 can be shifted
rearward. Thereby, the undesirable concentration of the external
force in the optical fiber 14 at the boundary portion between the
first region R1 and the second region R2 can be suppressed
further.
[0158] Also, in the optical receptacle 100, the holder 120 holds
only the portion of the ferrule 12 rearward of the first region R1.
Thereby, the undesirable concentration of the external force in the
optical fiber 14 at the boundary portion between the first region
R1 and the second region R2 can be suppressed further.
[0159] Further, in the optical receptacle 100, the holder 120 holds
the ferrule 12 only at the portion of the second outer perimeter
portion OS2. In other words, the periphery of the ferrule 12 is not
press-fitted into the housing 22. Thereby, for example, the
undesirable transfer, to the boundary portion between the first
region R1 and the second region R2 of the optical fiber 14 via the
holder 120, of the clamping force due to the press-fitting of the
holder 120 into the housing 22 can be suppressed. Accordingly, the
undesirable concentration of the external force in the optical
fiber 14 at the boundary portion between the first region R1 and
the second region R2 can be suppressed further. FIG. 6 is a
cross-sectional view illustrating a modification of the
pigtail-type optical receptacle according to the second
embodiment.
[0160] In the optical receptacle 100a as illustrated in FIG. 6, the
holder 120 holds the portion of the outer surface 12g of the
ferrule 12 rearward of the first region R1 and further holds the
portion of the outer surface 12g opposing the first region R1. In
the optical receptacle 100a, the first outer perimeter portion OS1
of the holder 120 is positioned rearward of the first region
R1.
[0161] Thus, in the case where the first outer perimeter portion
OS1 and the second outer perimeter portion OS2 are provided in the
holder 120, it is sufficient for at least the first outer perimeter
portion OS1 to be positioned rearward of the first region R1; and
the holder 120 may further hold the portion of the ferrule 12
opposing the first region R1.
[0162] In other words, it is sufficient for at least the periphery
of the boundary portion between the first region R1 and the second
region R2 not to be press-fitted into the housing 22. Even in such
a case, the undesirable transfer, to the boundary portion between
the first region R1 and the second region R2 of the optical fiber
14 via the holder 120, of the clamping force due to the
press-fitting of the holder 120 into the housing 22 can be
suppressed.
[0163] However, as illustrated in FIG. 5, the first outer perimeter
portion OS1 and the second outer perimeter portion OS2 may be
provided in the holder 120; and only the portion of the ferrule 12
rearward of the first region R1 may be held by the holder 120.
Thereby, the undesirable transfer to the optical fiber 14 of the
clamping force due to the press-fitting can be suppressed further.
The undesirable concentration of the external force in the optical
fiber 14 at the boundary portion between the first region R1 and
the second region R2 can be suppressed more appropriately.
[0164] FIG. 7 is a cross-sectional view illustrating a modification
of the pigtail-type optical receptacle according to the second
embodiment.
[0165] In the optical receptacle 100b as illustrated in FIG. 7, an
inner surface 122n of a housing 122 includes a first inner
perimeter portion 122a and a second inner perimeter portion 122b.
The first inner perimeter portion 122a engages the outer surface
20g of the holder 20. The inner diameter of the first inner
perimeter portion 122a is substantially the same as the outer
diameter of the holder 20. For example, the housing 122 is mounted
to the holder 20 by press-fitting the first inner perimeter portion
122a into the holder 20. For example, the first inner perimeter
portion 122a is formed in a ring configuration around the entire
perimeter of the inner surface 122n of the housing 122. For
example, multiple first inner perimeter portions 122a may be
provided to be arranged discretely along the inner perimeter of the
housing 122.
[0166] The second inner perimeter portion 122b is provided
frontward of the first inner perimeter portion 122a. The second
inner perimeter portion 122b widens outward from the first inner
perimeter portion 122a. The inner diameter of the second inner
perimeter portion 122b is larger than the inner diameter of the
first inner perimeter portion 122a.
[0167] The first inner perimeter portion 122a is positioned
rearward of the first region R1. Accordingly, the housing 122
engages the outer surface 20g of the holder 20 rearward of the
first region R1.
[0168] Thus, in the optical receptacle 100b, by setting the inner
diameter of the second inner perimeter portion 122b of the housing
122 to be large, the first inner perimeter portion 122a where the
holder 20 is held by the housing 122 can be shifted rearward.
Thereby, similarly to the optical receptacle 100 described in
reference to FIG. 5, etc., the undesirable concentration of the
external force in the optical fiber 14 at the boundary portion
between the first region R1 and the second region R2 can be
suppressed.
[0169] In FIG. 7, the holder 20 holds the first region R1 and the
second region R2. Even in the case where the housing 122 is used,
the holder 20 may hold only the portion of the ferrule 12 rearward
of the first region R1. Thereby, the undesirable transfer to the
optical fiber 14 of the clamping force due to the press-fitting can
be suppressed further.
[0170] FIG. 8A and FIG. 8B are cross-sectional views illustrating
modifications of the pigtail-type optical receptacle according to
the second embodiment.
[0171] In the housing 122 of an optical receptacle 100c as
illustrated in FIG. 8A, the second inner perimeter portion 122b is
connected to the first inner perimeter portion 122a via a tilted
surface 122c. In the housing 122 of an optical receptacle 100d as
illustrated in FIG. 8B, the second inner perimeter portion 122b is
connected to the first inner perimeter portion 122a via a curved
surface 122d. For example, the curved surface 122d has a concave
curved-surface configuration that is smoothly continuous with the
second inner perimeter portion 122b.
[0172] Thus, it is favorable for the first inner perimeter portion
122a and the second inner perimeter portion 122b to be connected
smoothly by the tilted surface 122c or the curved surface 122d.
Thereby, the housing 122 can be formed easily even in the case
where the first inner perimeter portion 122a and the second inner
perimeter portion 122b are provided in the inner surface 122n of
the housing 122. For example, the manufacturability of the housing
122 can be improved; and the manufacturing cost of the optical
receptacles 100c and 100d can be suppressed.
Third Embodiment
[0173] FIG. 9 is a cross-sectional view illustrating a pigtail-type
optical receptacle according to a third embodiment.
[0174] In the optical receptacle 200 as illustrated in FIG. 9, a
housing 222 is mounted on the front end side of a holder 220.
[0175] The holder 220 includes a mounting portion 220a for mounting
the housing 222. The mounting portion 220a is provided at the front
end portion of the holder 220. The housing 222 includes a mounted
portion 222a where the housing 222 is mounted to the mounting
portion 220a. The mounted portion 222a is provided at the rear end
portion of the housing 222. The mounting portion 220a and the
mounted portion 222a have tubular configurations. The mounted
portion 222a engages the outer side of the mounting portion 220a.
Thereby, the housing 222 is mounted on the front end side of the
holder 220.
[0176] The holder 220 includes a flange 220f. The flange 220f is
provided frontward of the second region R2. The front end of the
flange 220f is positioned frontward of the front end of the second
region R2. Also, the flange 220f protrudes outward from the housing
222 mounted to the mounting portion 220a. For example, the flange
220f is used in the positional alignment of the optical receptacle
200.
[0177] The mounting portion 220a is provided frontward of the
flange 220f. Accordingly, the housing 222 is mounted to the holder
220 frontward of the flange 220f.
[0178] In the optical receptacle 200, the flange 220f that
protrudes outward from the housing 222 is included; and the housing
222 is mounted to the holder 220 frontward of the flange 220f.
Thereby, for example, compared to the case where the housing 222 is
mounted to the holder 220 on the rear end side of the flange 220f,
the lengths of the ferrule 12, the holder 220, and the housing 222
can be shortened while suppressing the undesirable concentration,
of the external force caused by mounting the housing 222, in the
optical fiber 14 at the boundary portion between the first region
R1 holding the optical fiber 14 and the second region R2 not
holding the optical fiber 14. Accordingly, a pigtail-type optical
receptacle 200 that can be downsized without causing the decrease
of the reliability can be provided.
[0179] In FIG. 9, the holder 220 holds the first region R1 and the
second region R2. Even in a configuration in which the housing 222
is mounted, the holder 220 may hold only the portion of the ferrule
12 rearward of the first region R1. Thereby, the undesirable
transfer to the optical fiber 14 of the clamping force due to the
press-fitting can be suppressed further.
[0180] FIG. 10A and FIG. 10B are cross-sectional views illustrating
modifications of the pigtail-type optical receptacle according to
the third embodiment.
[0181] In an optical receptacle 200a as illustrated in FIG. 10A,
the housing 222 is mounted on the front end side of the holder 220
by the mounted portion 222a engaging the inner side of the mounting
portion 220a. Thus, the mounted portion 222a may engage the outer
side of the mounting portion 220a or may engage the inner side of
the mounting portion 220a. The configurations of the mounting
portion 220a and the mounted portion 222a are not limited to those
recited above; and any configuration in which the housing 222 is
mountable to the front end side of the holder 220 may be used.
[0182] In an optical receptacle 200b as illustrated in FIG. 10B,
the mounting portion 220a extends further frontward compared to the
mounting portion 220a of the optical receptacle 200 shown in FIG.
9. Thus, the position of the mounting portion 220a (the mounting
position of the housing 222) may be any position frontward of the
flange 220f.
Fourth Embodiment
[0183] FIG. 11 is a cross-sectional view illustrating a
pigtail-type optical receptacle according to a fourth embodiment.
As illustrated in FIG. 11, the optical receptacle 300 includes an
elastic member 302 (a second elastic member).
[0184] Other than the elastic member 302, the configuration of the
optical receptacle 300 is similar to the configuration of the
optical receptacle 10 of the first embodiment; and a detailed
description is therefore omitted. Other than the elastic member
302, the configuration of the optical receptacle 300 is not limited
to the configuration of the optical receptacle 10 and may be
similar to any of the optical receptacles 10a, 10b, 100, 100a to
100d, 200, 200a, and 200b described in the embodiments recited
above.
[0185] FIG. 12 is a partial cross-sectional view illustrating an
enlarged portion of the pigtail-type optical receptacle according
to the fourth embodiment.
[0186] As illustrated in FIG. 11 and FIG. 12, the elastic member
302 covers the corner portion between the rear end 20b of the
holder 20 and the outer surface of the protective member 16. In the
case where the elastic member 24 includes the protrusion 24p, the
elastic member 302 covers the protrusion 24p. For example, the
elastic member 302 covers the entire outer surface of the
protrusion 24p. In other words, the elastic member 302 covers the
boundary portion between the elastic member 24 and the protective
member 16.
[0187] The hardness of the elastic member 302 is lower than the
hardness of the elastic member 24. In other words, the elastic
modulus of the elastic member 302 is smaller than the elastic
modulus of the elastic member 24. The hardness of the elastic
member 24 is higher than the hardness of the protective member 16.
The hardness of the elastic member 302 is, for example, about the
same as the hardness of the protective member 16. The hardness of
the elastic member 302 is, for example, not less than 0.8 times and
not more than 1.2 times the hardness of the protective member 16.
The hardness of the protective member 16 is, for example, about
Shore D20-30. In such a case, similarly, the hardness of the
elastic member 302 is about Shore D20-30.
[0188] As described above, the protective member 16 includes a
resin material such as a polyester elastomer, an acrylate resin,
etc. As described above, the elastic member 24 includes a resin
material such as an epoxy resin, etc. The elastic member 302
includes, for example, a resin material such as a polyester resin,
an acrylic resin, a silicone resin, etc. The elastic member 24 and
the elastic member 302 include, for example, a resin bonding agent.
In such a case, the hardness of the elastic member 24 and the
hardness of the elastic member 302 are hardnesses after the curing
of the bonding agent (after completely curing).
[0189] A width W2 of the elastic member 302 at the first rear end
surface BS1 (the rear end surface) of the holder 20 is wider than a
width W1 of the elastic member 24 at the first rear end surface BS1
of the holder 20. More specifically, the width W1 and the width W2
are widths (lengths) in a direction orthogonal to the axial
direction. Also, the width W2 of the elastic member 302 in the
direction orthogonal to the axial direction is narrower than a
width Wbs of the first rear end surface BS1 in the direction
orthogonal to the axial direction. The width W1 of the elastic
member 24 is not more than the width (the outer diameter) of the
chamfer portion 20c of the holder 20 in the direction orthogonal to
the axial direction. In other words, the elastic member 24 does not
spread outward from the chamfer portion 20c.
[0190] A length L2 in the axial direction of the elastic member 302
is longer than a length L1 in the axial direction of the protrusion
24p of the elastic member 24. For example, the length L2 in the
axial direction of the elastic member 302 is not less than 2 times
and not more than 4 times the length L1 in the axial direction of
the protrusion 24p of the elastic member 24.
[0191] An average tilt angle .theta.2 between the outer surface of
the elastic member 302 and the first rear end surface BS1 of the
holder 20 is not less than an average tilt angle .theta.1 between
the outer surface of the protrusion 24p and the first rear end
surface BS1 of the holder 20.
[0192] Here, more specifically, the average tilt angle .theta.1 of
the outer surface of the protrusion 24p is, for example, the minor
angle of the angles between an imaginary line VL1 and directions
orthogonal to the axial direction. The imaginary line VL1 is, for
example, an imaginary line connecting a front end portion 24a of
the outer surface of the protrusion 24p in a cross section parallel
to the axial direction and a rear end portion 24b of the outer
surface of the protrusion 24p in the cross section. Similarly, the
average tilt angle .theta.2 of the outer surface of the elastic
member 302 is, for example, the minor angle of the angles between
an imaginary line VL2 and directions orthogonal to the axial
direction. The imaginary line VL2 is, for example, an imaginary
line connecting a front end portion 302a of the outer surface of
the elastic member 302 in a cross section parallel to the axial
direction and a rear end portion 302b of the outer surface of the
elastic member 302 in the cross section.
[0193] In FIG. 12, the outer surface of the elastic member 302 and
the outer surface of the protrusion 24p are illustrated as tilted
surfaces having linear configurations for convenience. The outer
surface of the elastic member 302 and the outer surface of the
protrusion 24p are not limited thereto and may have, for example, a
convex curved-surface configuration, a concave curved-surface
configuration, etc. The configuration of the outer surface of the
elastic member 302 and the configuration of the outer surface of
the protrusion 24p may be any configuration.
[0194] When bending the optical fiber 14 in handling, etc., stress
is applied easily to the optical fiber 14 at the base portion of
the optical fiber 14 protruding from the holder 20 (the rear end
portion of the holder 20); and breakage of the optical fiber 14
occurs easily. Therefore, the optical fiber 14 is coated with the
protective member 16 to relax the stress on the optical fiber 14.
Further, a protective member such as a tube (e.g., referring to
JP-A 2013-200352 (Kokai)), a boot (e.g., referring to JP-A
2016-224346 (Kokai)), etc., may be mounted at fundamental
portions.
[0195] However, in the case where a protective member such as a
tube, a boot, or the like is mounted, the holder 20, etc., must be
set to be longer by the amount covered with the protective member;
the length in the axial direction of the optical receptacle
undesirably lengthens; and a larger size of the product is
undesirably caused. Therefore, in the case where downsizing is
necessary, the optical fiber 14 is mounted in the product interior
in the state of being protected by only the protective member
16.
[0196] The protective member 16 is fixedly bonded to the holder 20
by the elastic member 24. Generally, the hardness of the protective
member 16 is lower than the hardness of the elastic member 24.
Therefore, when the optical fiber 14 is bent in handling, etc., the
stress generated at the boundary between the protective member 16
and the elastic member 24 is high; in the worst case, there is a
possibility that the protective member 16 may be damaged; and the
protection function of the optical fiber 14 may undesirably
decrease.
[0197] Conversely, by providing the elastic member 302 in the
optical receptacle 300 according to the embodiment, the starting
point of the bending when the optical fiber 14 is bent in handling,
etc., can be distal to the elastic member 24. In such a case, by
setting the hardness of the elastic member 302 to be lower than the
hardness of the elastic member 24, the stress that is applied to
the protective member 16 at the boundary with the elastic member
302 can be suppressed even when the optical fiber 14 is bent in
handling, etc. Thereby, the damage of the protective member 16 at
the boundary vicinity with the elastic member 24 and/or the elastic
member 302, etc., can be suppressed; and the risk of breakage of
the optical fiber 14 can be reduced further. Also, the larger size
of the product also can be suppressed compared to the case where a
protective member such as a tube, a boot, or the like is
provided.
[0198] Also, in the optical receptacle 300, the width W2 of the
elastic member 302 at the first rear end surface BS1 of the holder
20 is wider than the width W1 of the elastic member 24 at the first
rear end surface BS1 of the holder 20. Thereby, the wall thickness
of the elastic member 302 can be ensured appropriately regardless
of the final quality of the width W1 of the elastic member 24 at
the rear end surface of the holder 20; and the damage of the
elastic member 302 itself, etc., can be suppressed even when the
optical fiber 14 is bent by stress from the outside, etc.
[0199] In the optical receptacle 300, the width W2 of the elastic
member 302 in the direction orthogonal to the axial direction is
narrower than the width Wbs of the first rear end surface BS1 in
the direction orthogonal to the axial direction. Thereby, the flow
of the elastic member 302 to the second rear end surface BS2 can be
suppressed; and the appropriate positional alignment when
assembling is possible.
[0200] In the optical receptacle 300, the length L2 in the axial
direction of the elastic member 302 is longer than the length L1 in
the axial direction of the protrusion 24p. Thereby, the wall
thickness of the elastic member 302 can be ensured appropriately
regardless of the final quality of the length in the axial
direction of the protrusion 24p; and the damage of the elastic
member 302 itself, etc., can be suppressed even when the optical
fiber 14 is bent by stress from the outside, etc.
[0201] The length L2 of the elastic member 302 is, for example, not
less than 2 times the length L1 of the protrusion 24p. Thereby, the
damage of the elastic member 302 itself, etc., can be suppressed
more appropriately. Also, the length L2 of the elastic member 302
is, for example, not more than 4 times the length L1 of the
protrusion 24p. Thereby, the larger size of the product can be
suppressed appropriately.
[0202] In the optical receptacle 300, the average tilt angle
.theta.2 between the outer surface of the elastic member 302 and
the first rear end surface BS1 of the holder 20 is not less than
the average tilt angle .theta.1 between the outer surface of the
protrusion 24p and the first rear end surface BS1 of the holder 20.
Thereby, the wall thickness of the elastic member 302 can be
ensured appropriately regardless of the final quality of the width
of the elastic member 24 at the first rear end surface BS1 of the
holder 20; and the damage of the elastic member 302 itself, etc.,
can be suppressed even when the optical fiber 14 is bent by stress
from the outside, etc.
[0203] FIG. 13A to FIG. 13C are partial cross-sectional views
illustrating modifications of the pigtail-type optical receptacle
according to the fourth embodiment.
[0204] As illustrated in FIG. 13A, the average tilt angle .theta.2
between the outer surface of the elastic member 302 and the first
rear end surface BS1 may be smaller than the average tilt angle
.theta.1 between the outer surface of the protrusion 24p and the
first rear end surface BS1.
[0205] However, in such a case, the wall thickness of the elastic
member 302 undesirably becomes thin partially. For example, the
wall thickness of the elastic member 302 undesirably becomes thin
at the portion on the rear end side covering the boundary portion
between the elastic member 24 and the protective member 16.
Therefore, the risk of the damage of the elastic member 302 itself
undesirably increases when the optical fiber 14 is bent by stress
from the outside, etc. Accordingly, it is favorable for the tilt
angle .theta.2 to be the tilt angle .theta.1 or more. Thereby, as
described above, the wall thickness of the elastic member 302 can
be ensured appropriately; and the damage of the elastic member 302
itself, etc., can be suppressed.
[0206] As illustrated in FIG. 13B, the width W1 of the elastic
member 24 may be wider than the width of the chamfer portion 20c of
the holder 20 in the direction orthogonal to the axial direction.
The elastic member 24 may spread outward from the chamfer portion
20c.
[0207] However, in such a case, for example, the difference between
the width W1 of the elastic member 24 and the width W2 of the
elastic member 302 becomes small; and it is undesirably difficult
to form the elastic member 302. Also, the wall thickness of the
elastic member 302 at the vicinity of the first rear end surface
BS1 becomes thin; and the risk of the damage of the elastic member
302 itself undesirably increases. Accordingly, it is favorable for
the width W1 of the elastic member 24 to be not more than the width
of the chamfer portion 20c of the holder 20 in the direction
orthogonal to the axial direction. Thereby, for example, the
elastic member 302 can be formed easily. The wall thickness of the
elastic member 302 can be ensured appropriately; and the damage of
the elastic member 302 itself, etc., also can be suppressed.
[0208] As illustrated in FIG. 13C, the elastic member 24 may not
include the protrusion 24p. Even in such a case, by providing the
elastic member 302, the damage of the protective member 16 at the
boundary vicinity with the elastic member 24 and/or the elastic
member 302, etc., can be suppressed while suppressing the larger
size of the product; and the risk of breakage of the optical fiber
14 can be reduced further.
[0209] This embodiment includes the following aspects.
Aspect 1
[0210] A pigtail-type optical receptacle, comprising:
[0211] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0212] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0213] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0214] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0215] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule; and
[0216] a housing having a tubular configuration, engaging an outer
surface of the holder, and covering the ferrule and at least a
portion of the sleeve,
[0217] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule,
[0218] the holder holding a portion of the outer surface of the
ferrule rearward of the first region.
Aspect 2
[0219] The receptacle according to aspect 1, wherein a change of
the width in the orthogonal direction of the through-hole in the
second region has a curved configuration, the curved configuration
being convex toward a central axis side of the through-hole.
Aspect 3
[0220] The receptacle according to aspect 2, wherein
[0221] the through-hole of the ferrule further includes a third
region disposed rearward of the second region, and
[0222] a change of the width in the orthogonal direction of the
through-hole in the third region has a linear configuration.
Aspect 4
[0223] The receptacle according to aspect 1, wherein a front end of
the protective member is positioned inside the second region of the
through-hole.
Aspect 5
[0224] The receptacle according to aspect 3, wherein a front end of
the protective member is positioned inside the third region of the
through-hole.
Aspect 6
[0225] The receptacle according to aspect 1, wherein the holder
holds the rear end side of the ferrule by press-fitting.
Aspect 7
[0226] The receptacle according to aspect 1, wherein
[0227] a rear end of the holder is positioned rearward of the rear
end of the ferrule,
[0228] the holder surrounds a portion of the optical fiber and a
portion of the protective member, and the optical fiber and the
protective member further extend outside the holder and are fixedly
bonded to the holder by an elastic member filled into the
through-hole and into the holder.
Aspect 8
[0229] The receptacle according to aspect 7, wherein
[0230] an inner perimeter surface of the holder includes: [0231] a
first inner perimeter portion engaging the outer surface of the
ferrule; and [0232] a second inner perimeter portion positioned
rearward of the first inner perimeter portion, the second inner
perimeter portion protruding inward from the first inner perimeter
portion and surrounding a portion of the optical fiber and a
portion of the protective member,
[0233] a gap is provided in the axial direction between the second
inner perimeter portion and the rear end of the ferrule, and
[0234] the elastic member is filled also into the gap.
Aspect 9
[0235] The receptacle according to aspect 1, wherein the holder has
a first rear end surface and a second rear end surface, and
[0236] the second rear end surface is recessed frontward of the
first rear end surface on an outer perimeter side of the first rear
end surface.
Aspect 10
[0237] The receptacle according to aspect 1, wherein
[0238] the outer surface of the holder includes: [0239] a first
outer perimeter portion held by the housing; and [0240] a second
outer perimeter portion provided at a front end portion of the
holder, the second outer perimeter portion being recessed inward
from the first outer perimeter portion.
Aspect 11
[0241] The receptacle according to aspect 1, wherein the holder
includes a chamfer portion between a rear end surface and an inner
perimeter surface.
Aspect 12
[0242] The receptacle according to aspect 7, wherein the elastic
member includes a protrusion protruding outside the holder on the
rear end side of the holder and covering a corner portion between
the rear end of the holder and an outer surface of the protective
member.
Aspect 13
[0243] The receptacle according to aspect 1, wherein the housing
holds the holder by press-fitting.
Aspect 14
[0244] The receptacle according to aspect 1, wherein
[0245] the outer surface of the ferrule includes a first contact
portion contacting an inner perimeter surface of the holder,
[0246] the outer surface of the holder includes a second contact
portion contacting an inner perimeter surface of the housing,
and
[0247] an intermediate point in the axial direction of the second
contact portion is positioned rearward of an intermediate point in
the axial direction of the first contact portion.
Aspect 15
[0248] A pigtail-type optical receptacle, comprising:
[0249] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0250] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0251] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0252] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0253] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule; and
[0254] a housing having a tubular configuration, engaging an outer
surface of the holder, and covering the ferrule and at least a
portion of the sleeve,
[0255] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule,
[0256] the width in the orthogonal direction of the through-hole in
the second region changing in a curved configuration having a
proportion of the change increasing toward the rear end side.
Aspect 16
[0257] A pigtail-type optical receptacle, comprising:
[0258] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0259] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0260] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0261] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0262] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule; and
[0263] a housing having a tubular configuration, engaging an outer
surface of the holder, and covering the ferrule and at least a
portion of the sleeve,
[0264] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule,
[0265] the housing engaging the outer surface of the holder
rearward of the first region.
Aspect 17
[0266] The receptacle according to aspect 16, wherein
[0267] the outer surface of the holder includes: [0268] a first
outer perimeter portion held by the housing; and [0269] a second
outer perimeter portion provided at a front end portion of the
holder, the second outer perimeter portion being recessed inward
from the first outer perimeter portion, and
[0270] the first outer perimeter portion is positioned rearward of
the first region.
Aspect 18
[0271] The receptacle according to aspect 16, wherein
[0272] an inner surface of the housing includes: [0273] a first
inner perimeter portion engaging the outer surface of the holder;
and [0274] a second inner perimeter portion provided frontward of
the first inner perimeter portion, the second inner perimeter
portion widening outward from the first inner perimeter portion,
and
[0275] the first inner perimeter portion is positioned rearward of
the first region.
Aspect 19
[0276] The receptacle according to aspect 18, wherein the second
inner perimeter portion is connected to the first inner perimeter
portion via a tilted surface or a curved surface.
Aspect 20
[0277] A pigtail-type optical receptacle, comprising:
[0278] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0279] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0280] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0281] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0282] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule; and
[0283] a housing having a tubular configuration, being mounted to
the holder, and covering the ferrule and at least a portion of the
sleeve,
[0284] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule,
[0285] the holder including a flange protruding outward from the
housing, the flange being provided frontward of the second
region,
[0286] the housing being mounted to the holder frontward of the
flange.
Aspect 21
[0287] A pigtail-type optical receptacle, comprising:
[0288] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0289] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0290] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0291] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0292] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule;
[0293] a housing having a tubular configuration, engaging an outer
surface of the holder, and covering the ferrule and at least a
portion of the sleeve;
[0294] a first elastic member filled into the through-hole and into
the holder; and
[0295] a second elastic member covering a corner portion between a
rear end of the holder and the outer surface of the protective
member,
[0296] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule,
[0297] the holder holding a portion of the outer surface of the
ferrule rearward of the first region,
[0298] the rear end of the holder being positioned rearward of the
rear end of the ferrule,
[0299] the holder surrounding a portion of the optical fiber and a
portion of the protective member,
[0300] the optical fiber and the protective member further
extending outside the holder and being fixedly bonded to the holder
by the first elastic member,
[0301] a hardness of the second elastic member being lower than a
hardness of the first elastic member.
Aspect 22
[0302] A pigtail-type optical receptacle, comprising:
[0303] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0304] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0305] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0306] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0307] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule;
[0308] a housing having a tubular configuration, engaging an outer
surface of the holder, and covering the ferrule and at least a
portion of the sleeve;
[0309] a first elastic member filled into the through-hole and into
the holder; and
[0310] a second elastic member covering a corner portion between a
rear end of the holder and the outer surface of the protective
member,
[0311] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule,
[0312] the width in the orthogonal direction of the through-hole in
the second region changing in a curved configuration having a
proportion of the change increasing toward the rear end side,
[0313] the rear end of the holder being positioned rearward of the
rear end of the ferrule,
[0314] the holder surrounding a portion of the optical fiber and a
portion of the protective member,
[0315] the optical fiber and the protective member further
extending outside the holder and being fixedly bonded to the holder
by the first elastic member,
[0316] a hardness of the second elastic member being lower than a
hardness of the first elastic member.
Aspect 23
[0317] A pigtail-type optical receptacle, comprising:
[0318] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0319] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0320] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0321] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0322] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule;
[0323] a housing having a tubular configuration, engaging an outer
surface of the holder, and covering the ferrule and at least a
portion of the sleeve;
[0324] a first elastic member filled into the through-hole and into
the holder; and
[0325] a second elastic member covering a corner portion between a
rear end of the holder and an outer surface of the protective
member,
[0326] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule;
[0327] the housing engaging the outer surface of the holder
rearward of the first region,
[0328] the rear end of the holder being positioned rearward of the
rear end of the ferrule,
[0329] the holder surrounding a portion of the optical fiber and a
portion of the protective member,
[0330] the optical fiber and the protective member further
extending outside the holder and being fixedly bonded to the holder
by the first elastic member,
[0331] a hardness of the second elastic member being lower than a
hardness of the first elastic member.
Aspect 24
[0332] A pigtail-type optical receptacle, comprising:
[0333] a ferrule having a tubular configuration and having a
through-hole extending in an axial direction;
[0334] an optical fiber held by the ferrule in a state of being
inserted into the through-hole, the optical fiber extending outside
the ferrule from a rear end side of the ferrule;
[0335] a protective member covering a portion of the optical fiber
extending outside the ferrule;
[0336] a sleeve having a tubular configuration, engaging an outer
surface of the ferrule, and being mounted on a front end side of
the ferrule;
[0337] a holder having a tubular configuration, engaging the outer
surface of the ferrule, and holding the rear end side of the
ferrule;
[0338] a housing having a tubular configuration, being mounted to
the holder, and covering the ferrule and at least a portion of the
sleeve;
[0339] a first elastic member filled into the through-hole and into
the holder; and
[0340] a second elastic member covering a corner portion between a
rear end of the holder and an outer surface of the protective
member,
[0341] the through-hole of the ferrule including a first region and
a second region, a width in an orthogonal direction of the
through-hole in the first region corresponding to a width in the
orthogonal direction of the optical fiber, the orthogonal direction
being orthogonal to the axial direction, the second region being
disposed rearward of the first region, the width in the orthogonal
direction of the through-hole in the second region widening toward
the rear end side of the ferrule,
[0342] the holder including a flange protruding outward from the
housing, the flange being provided frontward of the second
region,
[0343] the housing being mounted to the holder frontward of the
flange,
[0344] the rear end of the holder being positioned rearward of the
rear end of the ferrule,
[0345] the holder surrounding a portion of the optical fiber and a
portion of the protective member,
[0346] the optical fiber and the protective member further
extending outside the holder and being fixedly bonded to the holder
by the first elastic member,
[0347] a hardness of the second elastic member being lower than a
hardness of the first elastic member.
Aspect 25
[0348] The receptacle according to aspect 21, wherein a width of
the second elastic member at a rear end surface of the holder is
wider than a width of the first elastic member at the rear end
surface of the holder.
Aspect 26
[0349] 26. The receptacle according to aspect 21, wherein
[0350] the holder has a first rear end surface and a second rear
end surface,
[0351] the second rear end surface is recessed frontward of the
first rear end surface on an outer perimeter side of the first rear
end surface, and
[0352] a width in a direction orthogonal to the axial direction of
the second elastic member is narrower than a width in the direction
orthogonal to the axial direction of the first rear end
surface.
Aspect 27
[0353] The receptacle according to aspect 21, wherein
[0354] the first elastic member includes a protrusion protruding
outside the holder on the rear end side of the holder,
[0355] the protrusion covers a corner portion between the rear end
of the holder and the outer surface of the protective member,
and
[0356] the second elastic member covers the protrusion.
Aspect 28
[0357] The receptacle according to aspect 27, wherein a length in
the axial direction of the second elastic member is longer than a
length in the axial direction of the protrusion.
Aspect 29
[0358] The receptacle according to aspect 27, wherein an average
tilt angle between an outer surface of the second elastic member
and a rear end surface of the holder is not less than an average
tilt angle between an outer surface of the protrusion and the rear
end surface of the holder.
[0359] Embodiments of the invention are described hereinabove.
However, the invention is not limited to these descriptions.
Appropriate design modifications performed by one skilled in the
art based on the embodiments described above also are within the
scope of the invention to the extent that the features of the
invention are included. For example, the configuration, the
dimensions, the material properties, the arrangement, etc., of each
component included in the optical receptacles 10, 10a, 10b, 100,
100a, 200, 200a, 200b, 300, etc., are not limited to those
illustrated and can be modified appropriately.
[0360] Also, the components included in the embodiments described
above can be combined within the limits of technical feasibility;
and such combinations are within the scope of the invention to the
extent that the features of the invention are included.
* * * * *