JP2003131082A - Bidirectional light transmitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bidirectional light transmitting device integrated with optical fiber that is surface mountable. SOLUTION: A single-core optical fiber 2 which a bidirectional light transmitting device 1 uses, is branched into 2a and 2b respectively in a bifurcation part 2c in the vicinity of both edges of a cable. In the bifurcation part 2c, a V-shaped groove is formed. The optical fiber 2a is inserted into a joined with a side 3a of a cover 3 made of a resin molding, and the other side 3b of the cover 3 has a recess 3c of a light receiving device 4. The cover 3 is formed with a plug form of a connector. A wire pattern is formed in a substrate 5 of the light receiving device 4 made of ceramic or glass epoxy resin. A translucent sealing resin 7 seals a light receiving element 6 loaded on and wired to a substrate 5. The optical fiber 2b is the same as the optical fiber 2a, wherein an optical fiber 2b is integrated with a light emitting device 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional optical transmission device which is applied to optical transmission transceivers, optical minijacks, and the like, and is particularly suitable for short-distance transmission.

[0002]

2. Description of the Related Art Optical fibers have a small diameter (about 0.1 mm in diameter), are lightweight (the specific gravity of glass is about 1/4 of the specific gravity of copper), and are excellent in flexibility (radius of curvature of several cm or less), electromagnetic. No induction, strong crosstalk, low loss (eg 1dB / k)
m) High-bandwidth transmission is possible and there are few resource problems. Therefore, the optical fiber cable transmission system is used in the field of WAN, which is the field of public communication, as well as the transmission system and data bus of the in-station configuration called LAN. It has a wide range of application fields such as, data link, and various measurement control systems.

Further, in the field of personal use called PAN, a diameter of about 1 m is conventionally used as a bidirectional optical transmission module applied to an optical transceiver transceiver, an optical minijack and the like.
A two-core optical fiber cable equipped with a dedicated optical fiber for reception using the core wire of m as an optical transmission line, and a light-receiving device including a light-receiving element on the receiving fiber side at this cable end A two-core bidirectional optical transmission module that performs signal processing by installing (Rx) on the transmission fiber side and a light emitting side device (Tx) including a light emitting element in a housing is used, and the light emitting side device (Tx) is also used.
x) and the light-receiving side device (Rx) are installed in a housing connected to both ends of a one-core optical fiber cable, and there is an optical transmission module for one-way transmission (here, the optical transmission device is housed in the housing). There was no bidirectional optical transmission device applicable to a small bidirectional optical transmission module that transmits and receives using a single-core optical fiber cable.

An example of a conventional two-core bidirectional optical transmission module will be described. First, the configuration will be described.
FIG. 4 is a sectional view of a conventional two-core bidirectional optical transmission module, and FIG. 5 is a front view of the conventional two-core bidirectional optical transmission module. In FIG. 4, reference numeral 71 denotes a two-core bidirectional optical fiber cable in which a receiving optical fiber 71a and a transmitting optical fiber 71b are bundled by using a plug component 71c. Reference numeral 80 is a two-core bidirectional optical transmission module, and 81 is its housing. 82 is an optical fiber 7
It is a partition having an opening for holding the tip portions of 1a and 71b. Reference numeral 83 is a light emitting device (Tx) disposed on the transmitting optical fiber 71b side, and 84 is a receiving optical fiber 7
It is a light-receiving side device (Rx) arranged on the 1a side.

The light emitting side device 83 is an IC of 86 for converting a logic level electric signal into a light emitting element driving signal.
And a light emitting element 87, which is an LED or LD for converting a modulated electric signal into an optical signal, are mounted on a lead frame 85 and sealed with a translucent resin 88. In the light-receiving side device 84, 89 light-receiving ICs in which a photodiode for converting an optical signal into an electric signal and an IC for further amplifying to a logic level are integrated are mounted on a lead frame 85 and sealed with a translucent resin 88. It has been stopped. As shown in FIG. 5, the lead frame 85 serves as a lead terminal and projects from the outer wall of the housing 81.

Next, the operation of the optical transmission module 80 will be described. The optical signal transmitted from the communication partner side through the receiving optical fiber 71a passes through the transparent resin 88, is input to the light receiving IC 89, and is converted into an electric signal. On the other hand, I
The light emitted from the light emitting element 87 via C86 is transparent resin 8
After passing through No. 8, the optical fiber enters into the transmission side optical fiber 71b, is transmitted therethrough, and is sent out to the communication partner side.

[0007]

However, in such a conventional two-core bidirectional optical transmission module, the center position of the optical fiber is high because of the structure in which the optical fiber is attached to and detached from the light emitting side device and the light receiving side device. It is difficult to maintain accuracy. Furthermore, since both devices are insertion mounting type components using a lead frame, a lot of man-hours are required for mounting on a circuit board of a portable electronic device.

The present invention has been made to solve such a conventional problem, and an object of the present invention is to connect a light receiving device and a light emitting device to the ends of respective optical fibers for transmission and reception and to provide two connectors. A bidirectional optical transmission device integrated with an optical fiber is provided.

[0009]

Means for Solving the Problems The means of the present invention for achieving the above-mentioned object is a bidirectional optical transmission device comprising a light emitting element and a light receiving element for transmitting and receiving an optical signal by an optical fiber, and for transmitting and receiving the signal. A light receiving device including a light receiving element is accommodated in one end of the optical fiber, and a cover accommodating a light emitting device including a light emitting element is joined to the other end, and a plug portion for mounting each of the covers in a housing. It is characterized in that it is formed so that.

Further, the invention is characterized in that a connection electrode is provided on a tip end surface of the plug portion.

Further, it is characterized in that it is attached to a housing having a receptacle portion to which the plug portion is attached.

A lead terminal is embedded in the housing so that one end extends to one surface of the housing, and the lead terminal is an anisotropic elastic connector provided on the bottom surface of the receptacle portion, and the light receiving device and the light emitting device. It is characterized in that it is connected to the connection electrode of the device.

Further, a one-core optical fiber is used as the optical fiber, and the optical fiber is branched to the other at a branching portion.
A V-shaped groove is provided in the branch portion.

The optical fiber is a two-core optical fiber.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION A bidirectional optical transmission device according to an embodiment of the present invention will be described in detail below with reference to the drawings. 1 is a cross-sectional view of a bidirectional optical transmission device that is an embodiment of the present invention, FIG. 2 is a cross-sectional view of a housing in which the bidirectional optical transmission device is mounted, and FIG. 3 is mounted on a motherboard of a mobile communication device or the like. It is a longitudinal cross-sectional view of the light transmission device on the side of the light receiving device showing the state.

First, the structure of this bidirectional optical transmission device will be described. In FIG. 1, 1 is a bidirectional optical transmission device, and 2 is a transmission line for bidirectionally transmitting an optical signal.
It is a core optical fiber. The optical fiber 2 is connected to the optical fibers 2a and 2 at the branching portion 2c near both ends of the cable.
It is branched to both b. A V-shaped groove is formed on the outside of the branch portion 2c.

Reference numeral 3 denotes a cover made of a resin molded product. The optical fiber 2a is inserted and joined from one end face 3a of the cover 3,
The receiving portion 3 for the light-receiving device is provided on the side of the other end surface 3b facing this.
have c. The cover 3 serves as a plug portion of the connector formed in a plug shape. Reference numeral 4 is a light receiving device, and 5 is a substrate of the light receiving device 4 made of ceramic or glass epoxy. A wiring pattern is formed on the substrate 5. 6 is an OEI mounted on the substrate 5 and wired
Reference numeral 7 denotes a light receiving element such as C, and reference numeral 7 denotes a translucent sealing resin that seals the light receiving element 6.

Reference numeral 8 denotes a connection electrode to the outside of the light receiving device 4, which is formed on the back surface of the substrate 5 which is the end surface of the plug portion of the cover 3. Reference numeral 13 denotes a light-emitting side cover similar to the light-receiving side, in which the optical fiber 2b is inserted and joined to one end face, and the end face side facing this has a housing portion for the light-emitting device 14. The covers 3 and 13 may be connected by some kind of connecting member or by forming a pair of both. A light emitting element 16 is mounted on the light emitting device 14, and other configurations are similar to those on the light receiving device 4 side.

In FIG. 2, reference numeral 20 designates a surface mount type housing of the bidirectional optical transmission device 1 having a receptacle portion 20a as a receptacle into which the covers 3 and 13 which are plug portions of the bidirectional optical transmission device 1 are inserted. Is. Two
Reference numeral 1 denotes a light-receiving side lead terminal embedded in the housing 20 so that one end thereof extends rearward along the bottom surface of the housing 20, and the other terminal surface is exposed at the bottom surface 20b of the receptacle portion 20a. Reference numeral 22 is also a lead terminal on the light emitting side. Reference numeral 23 denotes an elastic connector as an anisotropic conductive connector, which is used for connecting the connection electrode 8 of the light receiving device 4 and the connection electrode 16 of the light emitting device 14 to the lead terminals 21 and 22. 20b
It is installed in.

Next, the operation of this bidirectional optical transmission device will be described. In FIG. 3, reference numeral 30 denotes a mother board such as a mobile communication device, and when the housing 20 is mounted on the mother board 30, the lead terminals 21 and 22 can be soldered by utilizing a reflow furnace.
The bidirectional optical transmission device 1 is connected to the housing 20 to form an optical transmission module. An electric signal input from the mother board 30 through the lead terminal 22 of the light emitting device 14 is subjected to electric-optical energy conversion in the light emitting element 16. Then, the light emitted through the sealing resin 7 passes through the optical fiber 2b and is transmitted to the communication partner via the cable of the one-core optical fiber 2.

On the other hand, the light transmitted from the other party via the cable of the one-core optical fiber 2 partially goes to the optical fiber 2b at the branching portion 2c, but the rest goes to the optical fiber 2a. Head over. Then, the light is received by the light receiving device 4
Then, light-electrical energy conversion is performed in the light receiving element 8 through the sealing resin 7, and the light is output from the lead terminal 21 to the mother board 30 as an electric signal.

Next, the effect of the embodiment of the present invention will be described. Since the cable of the one-core optical fiber 2 is used as the transmission path, the cable cost is reduced, and the cable is easily bent and easily handled. The light emitted from the optical fiber 2b is
By providing the V-shaped groove in the branching portion 2c, it is possible to prevent the optical interference that occurs in the light receiving device 4 due to the wraparound on the optical fiber 2a side.

Further, by fixing the branched optical fibers 2a and 2b to the covers 3 and 13, the optical fiber 2
Since the two-way optical transmission device in which a, 2b, the light receiving device 4, and the light emitting device 14 are integrated is used, the optical fiber 2
Even when the a and 2b and the housing 20 are inserted and removed, the center positions of them are always unchanged. Furthermore, in the electrical connection with the lead terminals 21 and 22 of the receptacle portion 20a of the housing 20, since the elastic connector 23 is interposed, the mutual alignment accuracy may be rough. Therefore, the conversion of light-electrical energy is stable, and no defects due to the connection occur.

Further, in mounting on the mother board 30, since the lead terminals 21 and 22 of the housing 20 are extended along the bottom surface of the housing 20, it becomes possible to perform soldering by utilizing a reflow furnace, which results in mounting cost. Could be reduced.

In the above embodiment, a one-core optical fiber is used for bidirectional transmission and a branching portion is provided to branch to the other side. However, this is a two-core optical fiber. May be changed to

[0026]

As described above, according to the present invention,
Since the bidirectional optical transmission device in which the optical fiber, the light receiving device and the light emitting device are integrated is formed and the covers of both devices are formed in the shape of the plug of the connector, the optical fiber 2
Even when the a and 2b and the housing 20 are inserted and removed, the center positions of them are always unchanged, and stable optical transmission is realized.

Further, since the connection electrode of this bidirectional optical transmission device is electrically connected to the lead terminal embedded in the housing via the elastic connector, the mutual alignment accuracy may be rough and the connection failure may occur. It did not occur. Also, because the housing of the bidirectional optical transmission device is a surface mount type that has lead terminals exposed on the outer wall surface, when mounting the housing of the optical transmission module on the motherboard, the reflow process is effectively used to reduce costs. It came to be able to plan.

Further, since the V-shaped groove is formed in the branch portion of the one-core optical fiber, it is possible to prevent optical interference caused by the emitted light entering the light receiving device of the same module.
It has become possible to perform efficient bidirectional optical transmission even with a core optical fiber.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a bidirectional optical transmission device integrated with an optical fiber according to an embodiment of the present invention.

2 is a cross-sectional view of a housing of the bidirectional optical transmission device of FIG.

FIG. 3 is a vertical cross-sectional view showing a mounted state of the bidirectional optical transmission module.

FIG. 4 is a cross-sectional view of a conventional two-core bidirectional optical transmission module.

FIG. 5 is a front view of a conventional two-core bidirectional optical transmission module.

[Explanation of symbols]

1 Bidirectional optical transmission device 2, 2a, 2b optical fiber 2c branch 3,13 cover 4 Light receiving device 6 Light receiving element 8, 18 Connection electrode 14 Light emitting device 16 light emitting element 20 housing 20a Receptacle part 21,22 Lead terminal 23 Elastic Connector

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuaki Kayonuma             Yamanashi Prefecture Fujiyoshida City Kamigure 1-23-1             Citizen Electronics Co., Ltd. F-term (reference) 2H037 AA01 BA02 BA11 CA06 DA03                       DA04 DA06 DA35                 5F089 AA01 AB20 AC02 AC11 AC17                       CA20

Claims (6)

[Claims] 1. A bidirectional optical transmission device comprising a light emitting element for transmitting and receiving an optical signal by an optical fiber and a light receiving element, wherein a terminal of the optical fiber for transmission and reception accommodates a light receiving device including a light receiving element on one side. A two-way optical transmission device, characterized in that a cover and a cover accommodating a light-emitting device including a light-emitting element are joined to the other, respectively, so that each cover serves as a plug portion for attaching to the housing. . 2. The bidirectional optical transmission device according to claim 1, further comprising a connection electrode on a tip surface of the plug portion. 3. The bidirectional optical transmission device according to claim 1, wherein the bidirectional optical transmission device is mounted on a housing having a receptacle part to which the plug part is mounted. 4. A lead terminal is embedded in the housing so that one end extends to one surface of the housing, and the lead terminal is an anisotropic elastic connector disposed on a bottom surface of the receptacle portion, and the lead receiving terminal and the light emitting device. The bidirectional optical transmission device according to claim 3, wherein the bidirectional optical transmission device is connected to the connection electrode of the device. 5. An optical fiber having one core is used as the optical fiber, the optical fiber is branched to the other at a branching portion, and a V-shaped groove is provided at the branching portion. The bidirectional optical transmission device according to claim 4. 6. The bidirectional optical transmission device according to claim 1, wherein the optical fiber is a two-core optical fiber.