U.S. patent application number 10/902850 was filed with the patent office on 2005-02-03 for optical transmission device.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Oohira, Hiroaki, Saito, Hidenori, Sugizaki, Masayuki.
Application Number | 20050025436 10/902850 |
Document ID | / |
Family ID | 34106870 |
Filed Date | 2005-02-03 |
United States Patent
Application |
20050025436 |
Kind Code |
A1 |
Saito, Hidenori ; et
al. |
February 3, 2005 |
Optical transmission device
Abstract
An optical transmission device has a light emission element for
converting an electrical signal to an optical signal to transmit it
to an optical fiber; a lead frame for mounting the light emission
element and having a through hole at a position determined with
reference to a mounted position of the light emission element; and
a receptacle having a protrusion portion inserted in the through
hole to fix a position of the lead frame relatively, and a sleeve
into which an end portion of the optical fiber is inserted to fix a
position of the optical fiber relatively, the receptacle optically
connecting the light emission element and the optical fiber.
Inventors: |
Saito, Hidenori;
(Kanagawa-ken, JP) ; Sugizaki, Masayuki;
(Kanagawa-ken, JP) ; Oohira, Hiroaki;
(Kanagawa-ken, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
KABUSHIKI KAISHA TOSHIBA
Tokyo
JP
|
Family ID: |
34106870 |
Appl. No.: |
10/902850 |
Filed: |
August 2, 2004 |
Current U.S.
Class: |
385/88 |
Current CPC
Class: |
H01L 2224/48137
20130101; G02B 6/4292 20130101; G02B 6/4206 20130101; H01L
2224/48247 20130101 |
Class at
Publication: |
385/088 |
International
Class: |
G02B 006/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2003 |
JP |
2003-204451 |
Jul 16, 2004 |
JP |
2004-209490 |
Claims
What is claimed is:
1. An optical transmission device comprising: a photonic element
converting an electrical signal received from an optical
transmission path to an optical signal, or converting an optical
signal received from the optical transmission path to an electrical
signal; a mounting board mounting the photonic element and having
one of a hole and a notch at a position determined with reference
to a mounted position of the photonic element; and a coupling
portion having a protrusion portion inserted in one of the hole and
the notch to relatively fix a position of the mounting board, and
an optical transmission path insertion port in which an end portion
of the optical transmission path is inserted and which relatively
fixes a position of the optical transmission path, the coupling
portion optically coupling the photonic element and the optical
transmission path.
2. The optical transmission device according to claim 1, wherein
one of the plurality of holes and notches are provided at positions
almost symmetrical to one of a line passing through the photonic
element and a point of the photonic element.
3. The optical transmission device according to claim 1, wherein
one of the holes and the notches are provided on a circumference of
a circle with the photonic element of the mounting board at its
center, and the protrusion portions are provided on a circumference
of a circle with the optical transmission path of the coupling
portion at its center.
4. The optical transmission device according to claim 1, wherein
coupling portions of the respective protrusion portions connecting
with the coupling portions have an area larger than that of one of
the holes and the notches, and a distance between the photonic
element and the optical transmission path is determined by firmly
contacting a peripheral portion of the mounting board around one of
the hole and the notch with the connecting portion.
5. The optical transmission device according to claim 1, wherein
the protrusion portion has a caulking portion at its tip in order
to relatively fix a position of the mounting board.
6. The optical transmission device according to claim 1, wherein
the mounting board has the holes or the notches in plural
numbers.
7. The optical transmission device according to claim 1, wherein a
shape of at least one hole or notch among the holes or the notches
is a polygonal shape having three corners or more or constitutes a
part of the polygonal shape, and a cross-section shape of the
protrusion portion inserted in the polygonal hole or notch is also
a polygonal shape having three corners or more or constitutes a
part of the polygonal shape when viewed from a protrusion direction
thereof.
8. The optical transmission device according to claim 1, wherein a
shape of at least one hole or notch among the holes or the notches
is an elliptic shape or constitutes a part of the elliptic shape,
and a cross-section shape of the protrusion portion inserted in the
elliptic hole or notch is also a elliptic shape or constitutes a
part of the elliptic shape when viewed from a protrusion direction
thereof.
9. The optical transmission device according to claim 1, wherein
the holes or the notches are provided on the mounting board so as
to form an arc shape on a circumference of a circle with the
photonic element at its center, and the protrusion portions are
provided in the coupling portion so as to form an arc shape on a
circumference of a circle with the optical transmission path at its
center.
10. The optical transmission device according to claim 1, wherein
the coupling portion further includes a translucent lens provided
so as to be positioned in front of an end face of the optical
transmission path when the optical transmission path is inserted in
the optical transmission path insertion port.
11. The optical transmission device according to claim 1, wherein
the coupling portion is made of a translucent resin.
12. The optical transmission device according to claim 1, wherein
the coupling portion is made of a conductive material.
13. The optical transmission device according to claim 1, wherein a
hollow space is provided between the photonic element and the
coupling portion.
14. The optical transmission device according to claim 1, wherein
the mounting board is made of a ceramic.
15. The optical transmission device according to claim 1, wherein
the mounting board is made of a metal.
16. The optical transmission device according to claim 1, wherein
the mounting board and the coupling portion are a metal having an
affinity for solder.
17. The optical transmission device according to claim 1, wherein
the coupling portion is screwed to the mounting board.
18. The optical transmission device according to claim 1, wherein
the protrusion portions are fixed to the mounting board by
adhesive.
19. The optical transmission device according to claim 1, wherein
the protrusion portions have caulking portions having tips pointed
approximately toward a direction of the light emission element.
Description
CROSS REFFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority under 35 .sctn.119 to Japanese Patent Applications No.
2003-204451, filed on Jul. 31, 2003; and No. 2004-209490, filed on
Jul. 16, 2004, the entire contents of both of which are
incorporated by references herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an optical transmission
device performing a light transmission through an optical
fiber.
[0004] 2. Descriptions of the Related Arts
[0005] Optical transmission devices used between instruments close
to each other such as audio visual instruments and FA instruments
have mounted 660 nm-band red LEDs, and have been used at
transmission speeds ranging from several Mbps to 100 Mbps. As such
optical transmission devices, plastic fibers measuring 200 to 980
.mu.m in diameter, which are suitable for a wavelength of 660
nm-band, have been used.
[0006] In recent years, as digital devices have become more
advanced, a high speed transmission among them has been required.
Thus, laser diodes which can operate at a speed higher than LEDs
have been used for optical transmission devices. However, since
surface emitting-type laser diodes oscillate a laser light of 850
to 1550 nm-band, transmission loss becomes large with usage of the
plastic fiber having a core measuring 200 to 980 .mu.m in diameter.
Accordingly, to decrease the transmission loss, optical fibers
having a core measuring 50 .mu.m in diameter have come to be
used.
[0007] FIG. 18 is a cross section view showing an outline of a
conventional optical transmission device 10 taken along an optical
fiber 14 (for example, see Japanese Patent Laid-Open Publication
[KOKAI] 2002-344024). The optical transmission device 10 comprises
a light emission element 2 mounted on a lead frame 1 and a
peripheral IC 3 for driving a light emission element 2. A lead
frame 1, a light emission element 2 and a peripheral IC 3 are
electrically connected by a gold wire 4. A light emission element
2, a peripheral IC 3 and a gold wire 4 are sealed by resin 5. A
lens 6 is formed in front of a light emission surface of a light
emission element 2. With such structure described above, a lead
frame 1, a light emission element 2, a peripheral IC 3, a gold wire
4, resin 5 and a lens 6 constitute a light emission unit 7.
[0008] A receptacle 8 has an insertion port 11 for inserting a
light emission unit 7 and a sleeve 12 for inserting an end of a
optical fiber 14 which transmits an optical signal. An optical
fiber 14 is constituted by a core which forms its center, and a
clad surrounding the core, and the core and the clad are not
identified in the drawing. A light emission unit 7 is inserted
through a insertion port 11 of a receptacle 8, and fixed thereto
with adhesive 9. An optical connector 20 is composed of an optical
fiber 14, a connecting connector 15 and a ferrule 16. An optical
fiber 14 is fitted to a central portion of a ferrule 16, and a tip
portion of a ferrule 16 is designed so as to be flush with an end
face of an optical fiber 14. Note that the boundary between an
optical connector 20 and a receptacle 8 is represented by the thick
lines.
[0009] By inserting a ferrule 16 in a sleeve 12, the center axis of
an optical fiber 14 is positioned in line with the center axis of a
sleeve 12. Lights emitted from a light emission element 2 are
collected by a lens 6, and enter an optical fiber 14 through a
sleeve 12.
[0010] When an optical signal enters an optical fiber 14 through a
lens 6, an efficiency of coupling between a light emission element
2 and an optical fiber 14 is determined by a positional precision
of a lens 6 and an optical fiber 14. Specifically, the efficiency
of coupling between a light emission element 2 and an optical fiber
14 becomes higher, as the center axis of a lens 6 agrees more fully
with that of an optical fiber 14.
[0011] Nevertheless, the size of an inserting port 11 has been made
somewhat larger than the measurements of a light emission unit 7.
Therefore, a light emission unit 7 deviates from a specified
position in a receptacle 8 forward or backward, upward or downward
and left or right. Alternatively, a light emission unit 7
occasionally may tilt relative to a receptacle 8. In this case,
when a light emission unit 7 is fixed to a receptacle 8 with
adhesive 9, it has been difficult to make the center axes of a lens
6 and an optical fiber 14 agree with each other. In other words, in
a conventional optical transmission device 10, it has been
difficult to determine the relative positions of an optical fiber
14 and a light emission element 2 precisely.
[0012] In a case where the diameter of the optical fiber 14 is 200
.mu.m or more, if the center axes of a lens 6 and an optical fiber
14 disagree somewhat with each other, this has an insignificant
effect on the efficiency of optically coupling between an optical
fiber 14 and a light emission element 2. However, in a case where a
diameter of an optical fiber 14 is equal to about 50 .mu.m, the
disagreement of the center axes of a lens 6 and an optical fiber 14
with each other has a significant effect on the efficiency of
optically coupling between an optical fiber 14 and a light emission
element 2. In the future, when a diameter of an optical fiber 14 is
set to be further smaller than the present diameter thereof, the
disagreement of the center axes of a lens 6 and an optical fiber 14
will have a more significant effect on the efficiency of optically
coupling between an optical fiber 14 and a light emission element
2.
[0013] The respective center axes of a lens 6 and an optical fiber
14 are not constant among a plurality of optical transmission
devices 10. This implies that the efficiency of coupling between an
optical fiber 14 and a light emission element 2 varies for each
optical transmission device 10.
SUMMARY OF THE INVENTION
[0014] An optical transmission device according to an embodiment of
the present invention comprises: a photonic element converting an
electrical signal received from an optical transmission path to an
optical signal, or converting an optical signal received from the
optical transmission path to an electrical signal; a mounting board
mounting the photonic element and having one of a hole and a notch
at a position determined with reference to a mounted position of
the photonic element; and a coupling portion having a protrusion
portion inserted in one of the hole and the notch to relatively fix
a position of the mounting board, and an optical transmission path
insertion port in which an end portion of the optical transmission
path is inserted and which relatively fixes a position of the
optical transmission path, the coupling portion optically coupling
the photonic element and the optical transmission path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 1 of the present invention.
[0016] FIG. 2 is a front view showing an outline of a light
emission unit of the optical transmission device according to
Embodiment 1 of the present invention.
[0017] FIG. 3 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 2 of the present invention.
[0018] FIG. 4 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 3 of the present invention.
[0019] FIG. 5 is a front view showing an outline of a light
emission unit of the optical transmission device according to
Embodiment 3 of the present invention.
[0020] FIG. 6 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 4 of the present invention.
[0021] FIG. 7 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 5 of the present invention.
[0022] FIG. 8 is a front view showing an outline of a light
emission unit of the optical transmission device according to
Embodiment 5 of the present invention.
[0023] FIG. 9 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 6 of the present invention.
[0024] FIG. 10 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 7 of the present invention.
[0025] FIG. 11 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 8 of the present invention.
[0026] FIG. 12 is a front view showing an outline of a light
emission unit of the optical transmission device according to
Embodiment 8 of the present invention.
[0027] FIG. 13 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 9 of the present invention.
[0028] FIG. 14 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 10 of the present invention.
[0029] FIG. 15 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 11 of the present invention.
[0030] FIG. 16 is a cross section view showing an outline of an
optical transmission device taken along an optical fiber according
to Embodiment 12 of the present invention.
[0031] FIG. 17 is a front view showing an outline of a light
emission unit of the optical transmission device according to
Embodiment 12 of the present invention.
[0032] FIG. 18 is a cross section view showing an outline of a
conventional optical transmission device taken along an optical
fiber.
DETAILED DESCRIPTION OF THE INVENTION
[0033] Embodiments of the present invention will be described with
reference to the accompanying drawings below. In the drawings
described below, the same reference numerals and codes are given to
the same constituent components illustrated in certain drawings.
Furthermore, an optical fiber is composed of a core at its center,
and a clad surrounding the core. No identification between them is
made in the following drawings.
[0034] (Embodiment 1)
[0035] An optical transmission device according to Embodiment 1 of
the present invention will be described with reference to FIG. 1
and FIG. 2. FIG. 1 is a cross section view showing an outline of an
optical transmission device 100 taken along an optical fiber 14
which is an optical transmission path thereof. Note that, in this
cross section view, the constituent components which do not appear
in the cross section are virtually illustrated additionally. An
optical transmission device 100 comprises a light emission unit 107
and a receptacle 108 that is a coupling portion.
[0036] A light emission unit 107 includes a lead frame 101 that is
a mounting board, a light emission element 102 that is a photonic
element, a peripheral IC 103, a gold wire 104, a sealing resin 105
and a lens 106. A lead frame 101 is made of a metal, and mounts a
light emission element 102 and a peripheral IC 103. If an automatic
mounter is used in mounting a light emission element 102 on a lead
frame 101, a light emission element 102 can be fixed to a
predetermined position of a lead frame 101 with high precision. A
lead frame 101, a light emission element 102 and a peripheral IC
103 are electrically connected by a gold wire 104. A light emission
element 102 is operated by a peripheral IC 103, and converts an
electrical signal supplied from a peripheral IC 103 to an optical
signal. For example, a light emission element 102 that is a surface
emitting-type laser diode emits an optical signal in the direction
indicated with an arrow in FIG. 1.
[0037] A light emission element 102, a peripheral IC 103 and a gold
wire 104 are sealed by sealing resin 105. This sealing procedure is
performed by, for example, a transfer mold filling, and thus
precise positioning of a lens 106 is facilitated. A lens 106 is
provided in resin 105 in order to take out the optical signal from
a light emission element 102 with high efficiency.
[0038] FIG. 2 is a front view showing an outline of a light
emission unit 107 on which a light emission element 102 and a
peripheral IC 103 are mounted. As shown in FIG. 2, through holes
150, for example three of them, which are holes penetrating through
a lead frame 101 in its direction of thickness are provided at
positions determined relative to a mounted position of a light
emission element 102. The through holes 150 are disposed
symmetrically to the line A-A passing through a light emission
element 102. The outer edge of sealing resin 105 and the outer edge
of a lens 106 are indicated by the broken lines. FIG. 1 shows a
cross section view of an optical transmission device 100 taken
along the line A-A shown in FIG. 2.
[0039] A receptacle 108 that is an optical coupling portion will be
described with reference to FIG. 1 again. A receptacle 108
comprises a sleeve 112 that is an optical transmission path
insertion port for inserting an end portion of an optical fiber 14,
and a receiving portion 113 for receiving a connecting connector
15. A receptacle 108 is typically made of resin. In a sleeve 112,
the end portion of an optical fiber 14 is inserted, and thus a
sleeve 112 fixes the position of the end portion of an optical
fiber 14 relative to a receptacle 108. A connecting connector 15 is
received by a receiving portion 113, whereby the length of an
optical fiber 14 inserted in a sleeve 112 is determined.
[0040] A receptacle 108 further comprises protrusion portions 160
fitting the through holes 150. Through holes 150 and protrusion
portions 160 are provided in equal numbers, for example, three. The
diameter of through holes 150 and the cross-section diameter of
protrusion portions 160 when viewed from its protrusion direction
are approximately equal. Accordingly, when protrusion portions 160
are inserted in through holes 150, both of protrusion portions 160
and through holes 150 almost contact with each other, and the
position of a light emission element 102 relative to a receptacle
108 is fixed. As described above, a receptacle 108 relatively
determines the position of the end portion of an optical fiber 14
and the position of a light emission element 102, thus optically
connecting a light emission element 102 and an optical fiber
14.
[0041] The diameter of a connecting portion 165 near the base of a
protrusion portion 160 is larger than that of a through hole 150.
Thus, a lead frame 101 firmly contacts connecting portions 165,
whereby the distance between a light emission element 102 and a
receptacle 108 is determined.
[0042] After protrusion portions 160 are inserted in through holes
150, adhesive 109 is supplied to protrusion portions 160 and
through holes 150. Thus, the position of a light emission element
102 relative to a receptacle 108 and the distance between a light
emission element 102 and a receptacle 108 are determined. In the
above described manner, the position of a light emission element
102 or a lens 106 relative to an optical fiber 14 is determined.
Since an optical connector 20 is identical to that shown in FIG.
18, descriptions of it will be omitted.
[0043] The shape of through holes 150 is circular as shown in FIG.
2. The cross-section shape of protrusion portions 160 is also
circular as is the case with that of through holes 150. However,
according to this embodiment, since through holes 150 and
protrusion portions 160 are provided in plural numbers, the
position of the end portion of an optical fiber 14 and the position
of a light emission element 102 relative to a receptacle 108 are
determined in a mechanical manner, respectively. Accordingly, an
optical fiber 14, a light emission element 102 and a lens 106 can
be fixed to predetermined positions relative to a sleeve 112,
respectively. As a result, an efficiency of optically coupling
between an optical transmission device 100 and an optical connector
20 becomes stable. Specifically, a variation of the efficiency of
optically coupling between each optical transmission device 100
becomes smaller than conventional one.
[0044] Furthermore, through holes 150 and protrusion portions 160
are provided at precise positions relative to a light emission unit
107 and a receptacle 108 respectively, and the diameters of
protrusion portions 160 and through holes 150 are made to be almost
equal to each other, whereby an efficiency of optically coupling
between an optical fiber 14 and a light emission element 102
increases in comparison with conventional ones.
[0045] In this embodiment, in consideration for manufacturability
of an optical transmission device 100, through holes 150 are
provided in a lead frame 101, and protrusion portions 160 are
provided in a receptacle 108. However, protrusion portions may be
provided in a lead frame 101 and through holes may be provided in a
receptacle 108.
[0046] (Embodiment 2)
[0047] An optical transmission device according to Embodiment 2 of
the present invention will be described with reference to FIG. 3.
FIG. 3 is a cross section view showing an outline of an optical
transmission device 200 taken along an optical fiber 14 that is an
optical transmission path thereof. Note that, in this section view,
the constituent components which do not appear in the cross section
are virtually illustrated additionally. This embodiment differs
from Embodiment 1 in that a light emission unit 207 has no lens and
a lens 206 is provided in a receptacle 208. Other constituent
components of this embodiment may be the same as those in
Embodiment 1.
[0048] According to this embodiment, a lens 206 which collects
optical signals from a light emission element 102 is formed as-one
with a receptacle 208. A lens 206 needs to be translucent.
Accordingly, when a lens 206 and a receptacle 208 are formed
as-one, the entire of a receptacle 208 is also translucent. A lens
206 is provided at the end of a sleeve 112 so that the center axis
of a lens 206 and the center axis of a sleeve 112 agree with each
other.
[0049] In FIG. 3, a gap between a receptacle 208 and resin 105
exists. However, the gap between a receptacle 208 and resin 105
needs not exist. Specifically, a receptacle 208 and resin 105 may
be brought into intimate contact with each other.
[0050] By providing a lens 206 in a receptacle 208, the center axis
of a lens 206 agrees with that of a sleeve 112 without depending on
the position of a light emission unit 207 relative to a receptacle
208. Thus, it is possible to position the center axis of a lens 206
so as to be flush with that of an optical fiber 14. As a result,
the efficiency of optically coupling between an optical
transmission device 200 and an optical connector 20 increases and
becomes stable in comparison with conventional ones. Furthermore,
Embodiment 2 exhibits the same effects as those in Embodiment
1.
[0051] The front view of a light emission unit 207 is approximately
identical to that shown in FIG. 2, and is omitted. Since a lens is
not formed on sealing resin 105, a lens 106 shown by the broken
line in FIG. 2 is not present in this embodiment.
[0052] (Embodiment 3)
[0053] An optical transmission device according to Embodiment 3 of
the present invention will be described with reference to FIGS. 4
and 5. FIG. 4 is a cross section view showing an outline of an
optical transmission device 300 taken along an optical fiber 14
that is an optical transmission path thereof. Note that, in this
cross section view, the constituent components which do not appear
in the cross section are virtually illustrated additionally. In a
light emission unit 307 according to this embodiment, both of a
light emission element 102 and a peripheral IC 103 are not
resin-sealed. A resin 205 is provided on a lead frame 101 so as to
surround a light emission element 102 and a peripheral IC103. This
embodiment differs from Embodiment 2 in such respect. Other
constituent components of this embodiment may be the same as those
of Embodiment 2.
[0054] When a light emission unit 307 is fitted to a receptacle
208, a light emission unit 102 and a peripheral IC 103 are
hermetically sealed in a hollow space surrounded by a lead frame
101, a receptacle 208 and resin 205.
[0055] According to this embodiment, since resin 205 does not come
into direct contact with a light emission element 102, a light
emission element 102 does not deteriorate owing to the stress of
the resin. Furthermore, since reflection and refraction by the
resin does not occur, influences by the resin on an optical axis of
a light emission element 102 can be eliminated. Furthermore, this
embodiment can achieve the same effects as those in Embodiment
2.
[0056] FIG. 5 is a front view illustrating an outline of a light
emission unit 307 showing the position of resin 205 relative to a
lead frame 101. Resin 205 is illustrated by the broken lines. Resin
205 is provided on a lead frame 101 so as to surround a light
emission element 102 and a peripheral IC 103. FIG. 4 shows a
section of an optical transmission device 300 taken along the line
B-B illustrated in FIG. 5.
[0057] (Embodiment 4)
[0058] An optical transmission device according to Embodiment 4 of
the present invention will be described with reference to FIG. 6.
FIG. 6 is a cross section view showing an outline of an optical
transmission device 400 taken along an optical fiber 14 that is an
optical transmission path thereof. Note that, in this cross section
view, the constituent components which do not appear in the cross
section are virtually illustrated additionally. In a light emission
unit 407 according to this embodiment, both of a light emission
unit 102 and a peripheral IC 103 are mounted on a ceramic board
401, and they are not resin-sealed. This embodiment differs from
Embodiment 2 in this respect. Other constituent components of this
embodiment may be the same as those of Embodiment 2.
[0059] In a ceramic board 401, non-through holes 450 are provided.
By fitting protrusion portions 160 in holes 450, the positions of a
light emission element 102 and a receptacle 208 are relatively
determined.
[0060] Since a ceramic board 401 is ordinarily thicker than a lead
frame, holes 450 can be provided in a ceramic board 401 as
non-through holes. By forming holes 450 to be unpenetrated, it is
possible to fix a light emission unit 407 to a receptacle 208 by
adhering a light emission unit 407 to a receptacle 208 or inserting
a light emission unit 407 in a receptacle 208. A ceramic board 401
firmly contacts connecting portions 165, whereby the distance
between a light emission unit 102 and a receptacle 208 is
determined. Note that a ceramic board 401 may take any of a
single-layered structure and a multilayered structure, and a wiring
formed on the surface where a light emission unit 102 and the like
are mounted and a lead wire 411 connected to the surface on the
other side of the former plane are connected to each other by, for
example, a via-hole wiring (not shown).
[0061] According to this embodiment, a light emission element 102
and a peripheral IC 103 are hermetically sealed in a hollow space
surrounded by a ceramic board 401 and a receptacle 208.
Accordingly, this embodiment exhibits the same effects as those in
Embodiment 3.
[0062] Though non-through holes 450 are provided in a ceramic board
401 of this embodiment, the effects of this embodiment are not lost
even when through holes (not shown) are provided in a ceramic board
401.
[0063] (Embodiment 5)
[0064] An optical transmission device according to Embodiment 5 of
the present invention will be described with reference to FIGS. 7
and 8. FIG. 7 is a cross section view showing an outline of an
optical transmission device 500 taken along an optical fiber 14
that is an optical transmission path thereof. Note that, in this
cross section view, the constituent components which do not appear
in the cross section are virtually illustrated additionally. In
this embodiment, the number of through hole 550 provided in a lead
frame 501 is one, and has a polygonal shape having three corners or
more. The number of protrusion 560 provided in a receptacle 508 is
one as is the case with a through hole 550, and the protrusion
takes a polygonal shape having three corners or more in a section
perpendicular to its protrusion direction. This embodiment differs
from Embodiment 1 in this respect. Other constituent components of
this embodiment may be the same as those of Embodiment 1.
[0065] FIG. 8 is a front view showing an outline of a light
emission unit 507 having a lead frame 501. According to this
embodiment, only one through hole 550 is provided in a lead frame
501, and has, for example, a hexagonal shape. In accordance with
this, only one protrusion 560 (not shown) is provided in a
receptacle 508, and has a hexagonal shape. A through hole 550 and a
protrusion 560 are formed to a hexagonal shape having an
approximately equal size and identical shape. With such
constitution, a through hole 550 can accept a protrusion 560. FIG.
7 shows a cross section view of an optical transmission device 500
taken along the line C-C shown in FIG. 8.
[0066] According to this embodiment, since only one through hole
550 and one protrusion 560 are provided, a through hole 550 and a
protrusion 560 are formed to be polygonal. Accordingly, the
position of a light emission unit 507 relative to a receptacle 508
is determined. Furthermore, this embodiment exhibits the same
effects as those in Embodiment 1.
[0067] In this embodiment, a though through hole 550 and a
protrusion 560 are polygonal, the same effects as those of this can
be obtained when a through hole 550 and a protrusion 560 are formed
to be elliptic.
[0068] (Embodiment 6)
[0069] An optical transmission device according to Embodiment 6 of
the present invention will be described with reference to FIG. 9.
FIG. 9 is a cross section view showing an outline of the optical
transmission device taken along an optical fiber 14 that is an
optical transmission path thereof. Note that, in this cross section
view, the constituent components which do not appear in the cross
section are virtually illustrated additionally. In this embodiment,
a lead frame 601 and a receptacle 608 are made of metals having an
affinity for solder. Furthermore, a light emission unit 607 and a
receptacle 608 are fixed to each other with solder 609. This
embodiment differs from Embodiment 1 in this respect. Other
constituent components of this embodiment are the same as those of
Embodiment 1. This embodiment exhibits the same effects as those in
Embodiment 1. Note that since the front view of a light emission
unit 607 having a lead frame 601 is the same as that of FIG. 1, the
front view thereof is omitted.
[0070] (Embodiment 7)
[0071] An optical transmission device according to Embodiment 7 of
the present invention will be described with reference to FIG. 10.
FIG. 10 is a cross section view showing an outline of an optical
transmission device 700 taken along an optical fiber 14 that is an
optical transmission path thereof. Note that, in this cross section
view, the constituent components which do not appear in the cross
section are virtually illustrated additionally. This embodiment
differs from Embodiment 1 in that a light emission unit 107 is
screwed to a receptacle 708. A protrusion portion 760 of a
receptacle 708 has a screw-groove on its side surface. A shape in
the section of protrusion portions 760 is approximately the same as
that of through holes 150 of a lead frame 101. Accordingly,
protrusion portions 760 are accepted in through holes 150 as is the
case with Embodiment 1.
[0072] After protrusion portions 706 are accepted in through holes
150, nuts 770 are fitted on protrusion portions 760. A lead frame
101 is firmly contacted with a connecting portion 165 of a
protrusion portion 760, whereby the distance between a light
emission element 102 and a receptacle 708 is determined. Thus, in
this embodiment, a light emission unit 107 can be fixed to a
receptacle 708 without using adhesive or solder. This embodiment
exhibits the same effects as those in Embodiment 1.
[0073] (Embodiment 8)
[0074] An optical transmission device according to Embodiment 8 of
the present invention will be described with reference to FIG. 11
and FIGS. 12(a) and 12(b). FIG. 11 is a cross section view showing
an outline of an optical transmission device 800 taken along an
optical fiber 14 that is an optical transmission path thereof. Note
that, in this cross section view, the constituent components which
do not appear in the cross section are virtually illustrated
additionally. This embodiment is different from Embodiments 1 to 7
in that an optical transmission device of this embodiment further
comprises a sleeve member 821 in addition to a receptacle 808 as a
coupling portion for optically coupling a light emission element
102 to an optical fiber 14. Although, with such constitution, the
structures of a connecting connector 15 and a ferrule 16 are
somewhat changed, descriptions will be made by giving the same
reference numerals and codes and the same names as those of the
above described embodiments to the corresponding constituent
components. Although a light emission unit 807 differs from a light
emission unit 107 shown in FIG. 1 in a lead frame 801, other
constituent components may be the same as those of the above
described embodiments.
[0075] FIGS. 12(a) and 12(b) are front views showing outlines of
light emission units 807 and 907 on which light emission elements
102 and peripheral IC 103 are mounted. In FIGS. 12(a) and 12(b),
the positions of the respective outer peripheries of lenses 106,
sealing resin 105 and sleeve members 821 corresponding therein are
illustrated by the broken lines indicated by the same reference
numerals. In FIG. 12(a), a lead frame 801 has arc-shaped through
holes 850 on the circumference of a circle with a light emission
element 102 at its center. Three through holes 850 are provided in
a lead frame 801, and through holes 850 are arranged so as to be
apart from each other at intervals of 120.degree. or approximately
120.degree. and symmetrically to the line D-D. On the other hand,
in FIG. 12(b), a lead frame 801 shows the case where a lead frame
801 has notches 870 provided along an arc on the circumference of a
circle with a light emission element 102 at its center instead of
through holes 850 shown in FIG. 12(a). FIG. 11 shows a cross
section view of an optical transmission device 800 taken along the
line D-D shown in FIG. 12(a).
[0076] Referring to FIG. 11 again, a sleeve member 821 is made of
translucent resin. The end portion of an optical fiber 14 is
inserted in a sleeve member 821, whereby the position of the end
portion of an optical fiber 14 relative to a sleeve member 821 is
fixed. A sleeve member 821 comprises protrusion portions 860 so as
to match through holes 850 shown in FIG. 12(a). Specifically,
protrusion portions 860 have an arc-shaped section when viewed from
its protrusion direction. Through holes 850 and protrusion portions
860 are provided in equal numbers, and in plural numbers. After
protrusion portions 860 are inserted in through holes 850,
protrusion portions 860 and through holes 850 are fixed to each
other by adhesive 109. With such structure, the position of a light
emission element 102 relative to a sleeve member 821 is fixed.
[0077] A light emission element 102 is located at the center of the
circle on which three through holes 850 are provided. An optical
fiber 14 is located at center of the end portion of a sleeve member
821, that is, at the center of the outer circumference contacting a
light emission unit 807. Accordingly, protrusion portions 860 are
inserted in through holes 850 so as to match both centers, whereby
the centers of a light emission element 102 and an optical fiber 14
almost agree with each other. Thus, a light emission element 102
and an optical fiber 14 are optically coupled. A receptacle 808 is
fitted to the respective external peripheries of a sleeve member
821, a connecting connector 15 and a light emission unit 807, and
stabilizes the relative positions of them. This embodiment exhibits
the same effects as those of
[0078] Embodiment 1.
[0079] In this embodiment, when arc-shaped notches 870 are disposed
on the circumference of the circle with a light emission element
102 at its center as shown in FIG. 12(b), the same effects obtained
by foregoing through holes 850 of FIG. 12(a) can be achieved.
[0080] (Embodiment 9)
[0081] An optical transmission device according to Embodiment 9 of
the present invention will be described with reference to FIG. 13.
FIG. 13 is a cross section view showing an outline of an optical
transmission device 900 taken along an optical fiber 14 that is an
optical transmission path thereof. Note that, in this section view,
the constituent components which do not appear in the cross section
are virtually illustrated additionally. In this embodiment, a light
emission unit 807 is fixed to a sleeve member 821 by heat caulking
832. Furthermore, a receptacle 808 is fixed to a sleeve member 821
by heat caulking 833. This embodiment is different from Embodiment
8 in these respects. Other constituent components of this
embodiment may be the same as those in Embodiment 8.
[0082] After protrusion portions 860 are inserted in through holes
850 of a light emission unit 807, the tip ends of protrusion
portions 860 undergo a heat treatment. With the heat treatment,
heat caulking 832 is formed at the tip end of protrusion portions
860. Thus, the position of a light emission element 102 relative to
a sleeve member 821 is fixed.
[0083] Furthermore, after a receptacle 808 is fitted to the outside
of a sleeve member 821, heat caulking 833 is formed by performing
the heat treatment while applying pressure to a sleeve member 821
from the exterior surface of a receptacle 808. A receptacle 808 is
fixed to a sleeve member 821 by heat caulking 833.
[0084] According to this embodiment, adhesive, solder and nuts are
unnecessary. Furthermore, this embodiment exhibits the same effects
as those of Embodiment 8. When notches (not shown) are provided
instead of through holes 850 as is the case with Embodiment 8, the
same effects as those in this embodiment can be obtained.
[0085] (Embodiment 10)
[0086] An optical transmission device according to Embodiment 10 of
the present invention will be described with reference to FIG. 14.
FIG. 14 is a cross section view of an optical transmission device
1000 taken along an optical fiber 14 that is an optical
transmission path thereof. Note that, in this cross section view,
the constituent components which do not appear in the cross section
are virtually illustrated additionally. In this embodiment, a light
emission unit 807 is fixed to a sleeve member 821 by bending and
heat caulking 932. This embodiment differs from Embodiment 9 in
this respect. Other constituent components of this embodiment may
be the same as those of Embodiment 9.
[0087] After protrusion portions 860 are respectively inserted in
through holes 850 of a light emission unit 807, the tips of three
protrusion portions 860 simultaneously undergo a heat treatment and
a treatment in which a force is applied in a direction of a light
emission element 102. With such treatments, heat caulking 932 bent
in the direction of a light emission element 102 is formed in each
of the tips of protrusion portions 860. Thus, the position of a
light emission element 102 relative to a sleeve member 821 is
fixed.
[0088] According to this embodiment, the same effects as those of
Embodiment 9 can be exhibited. In addition, since the force is
simultaneously applied to the tips of three protrusion portions 860
in the direction of a light emission element 102 which is the
center of the circumference on which protrusion portions are
provided, of a light emission element 102, a positional deviation
of a light emission element 807 relative to a sleeve member 821 can
be suppressed to a small extent, and an optical coupling of a light
emission element 102 and a optical fiber 14 can be stabilized. Note
that, as is the case with Embodiment 8, an optical transmission
device can achieve the same effects as those of this embodiment
when notches (not shown) instead of through holes 850 are used.
[0089] (Embodiment 11)
[0090] An optical transmission device according to Embodiment 11 of
the present invention will be described with reference to FIG. 15.
FIG. 15 is a cross section view of an optical transmission device
100 taken along an optical fiber 14 that is an optical transmission
path thereof. Note that, in this section view, the constituent
components which do not appear in the cross section are virtually
illustrated additionally. In a light emission unit 1007 of this
embodiment, both of a light emission element 102 and a peripheral
IC 103 are mounted on a ceramic board 1001. This embodiment differs
from Embodiment 10 in this respect. Other constituent components of
this embodiment may be the same as those of Embodiment 10. A light
emission unit of this embodiment differs from a light emission unit
of Embodiment 4 using the same ceramic board as that of this
embodiment in that a light emission unit of this embodiment is
sealed by sealing resin 105 in which a lens is provided.
[0091] After protrusion portions 860 are respectively inserted in
through holes 1050 of a light emission unit 1007, the tips of three
protrusion portions 860 simultaneously undergo a heat treatment and
a treatment in which a force is applied in a direction of a light
emission element 102. With such treatments, heat caulking 1032 bent
in the direction of a light emission element 102 is formed in each
of the tips of protrusion portions 860. Thus, the position of a
light emission element 102 relative to a sleeve member 821 is
fixed. Note that, as is the case with Embodiment 4, a ceramic board
1001 may take any of a single-layered structure and a multilayered
structured, and a wiring formed on the plane where a light emission
unit 102 and the like are mounted and a lead wire 1011 connected to
the plane on the other side of the former plane are connected to
each other by, for example, a via-hole wiring (not shown).
[0092] According to this embodiment, the same effects as those of
Embodiment 10 are exhibited. Note that, as is the case with
Embodiment 8, an optical transmission device can achieve the same
effects as those of this embodiment when notches (not shown)
instead of through holes 1050 are used.
[0093] (Embodiment 12)
[0094] An optical transmission device according to Embodiment 12 of
the present invention will be described with reference to FIGS. 16
and 17. FIG. 16 is a cross section view of a optical transmission
device 1200 taken along an optical fiber 14 that is an optical
transmission path thereof. Note that, in this cross section view,
the constituent components which do not appear in the cross section
are virtually illustrated additionally. In a light emission unit
1107 of this embodiment, both of a light emission element 102 and a
peripheral IC 103 are mounted on a stem 1101, and sealed by a cap
1105 in which a lens 1106 is provided. This embodiment differs from
the Embodiment 11 in these respects. Other constituent components
of this embodiment may be the same as those of Embodiment 11.
[0095] A light emission unit 1107 includes a stem 1101 that is a
mounting board, a light emission element 102, a peripheral IC 103,
a gold wire 104, a cap 1105 and a lens 1106. A stem 1101 is made of
a metal, and mounts a light emission element 102 and a peripheral
IC 103. If an automatic mounter and the like are used when a light
emission element 102 is mounted on a stem 1101, a light emission
element 102 can be fixed to a predetermined position of a stem 1101
precisely. A lead 1111 extending in the direction perpendicular to
the plane of a stem 1101 is electrically connected to a stem 1101,
and a lead 1111 insulated by, for example, glass 1110 is connected
to a stem 1101. A lead 1111 is electrically connected to a light
emission element 102 and a peripheral IC 103 by a gold wire
104.
[0096] FIG. 17 is a front view showing an outline of a light
emission unit 1107 on which a light emission element 102 and a
peripheral IC 103 are mounted. Illustrations of a lead 1111 and a
gold wire 104 and the like are omitted. As shown in FIG. 17, in a
stem 1101 having a circular external shape, a light emission
element 102 is located at the center of the circle, and notches
1170, for example three of them, having the same shape are provided
on the circumference of the concentric circle. These notches 1170
have surface forming a part of the circumference of the circle, and
are arranged at equal intervals so as to be apart at intervals of
120.degree. from each other. A cap 1105 made from a metal disposed
so that the center of a lens 1106 is vertically just above that of
a light emission element 102 is fixed to a stem 1101, and
hermetically seals a light emission element 102, a peripheral IC
103 and the like. FIG. 16 shows a cross section view of an optical
transmission device 1200 taken along the line E-E shown in FIG.
17.
[0097] Referring to FIG. 16 again, after protrusion portions 860
are respectively inserted in notches 1170 of a light emission unit
1107, the tips of three protrusion portions 860 simultaneously
undergo a heat treatment and a treatment in which a force is
applied in a direction of a light emission element 102. With such
treatments, heat caulking 1132 bent in the direction of a light
emission element 102 is formed in each of the tips of protrusion
portions 860. Thus, the position of a light emission element 102
relative to a sleeve member 821 is fixed.
[0098] According to this embodiment, the same effects as those of
Embodiment 11 are exhibited. In addition, an optical coupling of an
optical fiber 14 and a light emission element 102 of a light
emission unit 1107 having a structure excellent in a hermetic seal
can be stabilized, and it is possible to provide the optical
transmission device capable of operating under severe environment.
Note that an optical transmission device can achieve the same
effects as those of this embodiment when through holes (not shown)
instead of notches 1170 are used.
[0099] The present invention is not limited to the above described
embodiments, and various modifications can be embodied without
departing from the scope and spirit of the present invention.
[0100] For example, in Embodiment 5 to Embodiment 7, a receptacle
208 shown in FIG. 3 may be used instead of receptacles 508, 608 and
708. In this case, a lens 106 needs not to be provided in a sealing
resin 105 of a light emission unit 107. With such structure, the
same effects as those of Embodiment 2 are added to the effects of
Embodiments 5 to 7.
[0101] In Embodiments 8 to 12, lenses 106 and 1106 may be provided
in sleeve members 821 as is similar to the structure shown in FIG.
3. With such structure, the same effects as those of Embodiment 2
are added to the effects of Embodiments 8 to 12.
[0102] The lens may adopt a two group system in which the lens is
provided in the light emission unit as well as in the sleeve
member. Based on several factors such as the distance between a
light emission element 102 and an optical fiber 14 and the material
of a lens, a selection by which the most suitable optical coupling
efficiency can be obtained is possible.
[0103] Furthermore, in Embodiments 9 to 12, the examples were
shown, in which the positional precision of a light emission
element 102 and a optical fiber 14 is secured by simultaneously
forming heat caulking 1132 of protrusion portions 860 inserted in
three through holes 850 and 1050 or three notches 870 and 1170
arranged on the concentric circle while applying the force toward
the center of a sleeve member 821. In addition to this example, the
same effects as those described above can be achieved by arranging
through holes or notches at diametrically opposite positions and by
simultaneously performing heat caulking for protrusion portions
inserted in these holes or notches while applying a force toward
the center. In this case, the through holes and the notches are
arranged in even numbers, for example, by four when the lines
respectively connecting the opposite two through holes or notches
intersect at the right angle.
[0104] Although a light emission element 102 is used in the above
described embodiments, a light receiving element (not shown) may be
used instead of the light emission element. Specifically, this
embodiment may be constituted as an light emission device or a
light receiving device (not shown). In this case, the light
receiving device is constituted so that it receives an optical
signal from an optical fiber 14, and converts the optical signal to
an electrical signal. As a matter of course, accompanied with the
adoption of the light receiving element, the peripheral IC is
changed for use in receiving the electrical signal.
[0105] Furthermore, though non-conductive resin is used as the
receptacle and the sleeve member of the above described
embodiments, they may be made of conductive materials. For example,
when the receptacle and the sleeve member need not to be
translucent, they may be made of metals, or they may be made of
resin mixed with metal filler. Particularly, when the embodiments
of the present invention are constituted as the light receiving
device, this light receiving device can decrease electromagnetic
noises by making the receptacle or the sleeve member to be
conductive.
* * * * *