JP2592853Y2 - Optical module - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical module used for converting between an optical signal and an electric signal in a communication device.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional optical module of this kind.

This optical module comprises a housing 1, a lot lens 2, a ferrule 3, and an optical element package (light emitting element or light receiving element) 4.

[0004] The housing 1 is formed of metal.
It is attached to the housing 6 of the communication device. This housing 1
Has a through hole 1a extending from one end to the other end, and a recess 1b communicating with the through hole 1a is formed at the other end. A male screw 1c is formed concentrically with the through hole 1a on the outer periphery of one end, and a male screw 1d is formed concentrically with the recess 1b on the outer periphery of the other end.

A rod lens 2 is bonded and fixed in the through hole 1a of the housing 1 in the vicinity of the concave portion 1b. The optical element package 4 is inserted into the concave portion 1b so as to face the rod lens 2. The cover 8 is screwed into the external thread 1 d of the housing 1, so that the flange 4 a provided at the end of the cover is screwed through the ring 9 into the concave bottom surface 1 e.
And is fixed to the housing 1.
The leads 4b of the optical element package 4 are connected to a printed wiring board (not shown) in the housing 6.

A through hole is formed in the ferrule 3, and the optical fiber 11 is fixed to the ferrule 3 by inserting the distal end of the core wire 11 a into the through hole. The ferrule 3 is inserted into the through hole 1a from one end of the housing 1, and the tip of the optical fiber core 11a is
Is positioned in a state of facing. When the cover 13 is screwed into the male screw 1c of the housing 1, the flange portion 3a of the ferrule 3 is
And is fixed to the housing 1.

In this optical module assembling procedure, first, the rod lens 2 is inserted into the through hole 1a, and the rod lens 2 is fixed to the housing 1 with an adhesive. Next, the ferrule 3 is inserted into the through hole 1 a from one end side of the housing 1 and fixed to the housing 1 by the cover 13. Next, the optical element package 4 is inserted into the concave portion 1b, and the optical element package 4 is moved while the flange 4a is in contact with the concave bottom surface 1e to adjust the optical axis with the ferrule 3 and screwed into the male screw 1d. The cover 8 is tightened and the flange is
The optical element package 4 is fixed to the housing 1 by pressing the 4a against the bottom surface 1e of the concave portion, thereby completing the process.

According to the conventional optical module, the flange 3a of the ferrule 3 is brought into contact with the end face 1f of the housing, and the flange 4a of the optical element package 4 is used to bring the optical element package 4 close to the rod lens 2.
Since the distance between the optical element package 4 and the ferrule 3 cannot be adjusted at the time of assembling, it is necessary to adjust the optical axes of the optical elements 3 and 4 alone to obtain a predetermined performance. The accuracy had to be very high.

The optical element package 4 is fixed to the housing 1 by tightening the cover 8 and pressing the optical element package 4 against the concave wall surface 1e. The optical element package 4 is fixed by a large force acting on the optical element package 4 at the time of fixing.
Since the optical axis itself is easily displaced, it has been very difficult to adjust the optical axis.

[0010]

As described above, in the above optical module, the distance between the optical element package and the ferrule cannot be adjusted at the time of assembly, so that the accuracy of optical axis adjustment and the accuracy of parts at the time of assembly are extremely high. I needed to.

The present invention has been made to solve such a conventional disadvantage, and provides an optical module which can adjust the distance between the optical element package and the ferrule in addition to the optical axis adjustment during assembly. The purpose is to do.

[0012]

An optical module according to the present invention has a first through hole, a rod lens is attached to one end of the first through hole, and the rod lens is attached to the other end. A concave portion is formed in which the flange portion of the optical element package is mounted in a state facing the end surface on one end side of the rod lens, a screw is formed on the outer peripheral portion, and further, the outer peripheral portion of the portion to which the rod lens is mounted A fixing body having a first step formed at a boundary between the fixing step and the screw portion; and covering the other end side of the fixing body so as to wrap the flange buried in the concave portion. mosquitoes hole to project an optical device package which leads to part are formed
A bar , a ferrule that holds the tip of the optical fiber, has a flange, and a fixture in which the ferrule is inserted from one end and a nut is coupled to the fixture main body from the other end is the rod. A second through hole for adjusting the optical axis and the distance between the lens and the ferrule and inserting the ferrule is formed, a screw is formed on an outer peripheral portion on a side where the ferrule is inserted, and further when the fixing tool is inserted. A second step portion serving as a stopper of the housing is formed corresponding to the first step portion of the main body, and a flange of the ferrule is used as a stopper when the ferrule is inserted into the second through hole. And a cover for covering the flange.

[0013]

In the present invention, the optical element package and the rod lens are integrated via a fixture, and the positional relation between the optical element package and the rod lens is not changed by slightly moving the fixture with respect to the housing. , The position of the optical element package with respect to the ferrule can be adjusted.
At the time of assembly, the optical axis of the optical element package and the ferrule can be adjusted, and the distance between them can be adjusted.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS.

FIGS. 1 and 2 are views for explaining a first embodiment. FIG. 1 is a partially cutaway perspective view of an optical module, and FIG. 2 is a sectional view of the optical module.

The optical module according to the present invention comprises a housing 21, a ferrule 22, an optical element package (light emitting element or light receiving element) 23, a rod lens 24, and an optical element package 23 and a fixture 25 for fixing the rod lens 24. Have been.

The ferrule 22 has a through hole as in the prior art, and the optical fiber 27 is fixed to the ferrule 22 with the distal end of the core wire 27a inserted into the through hole. Flange 2 in the middle of ferrule 22
2a is provided.

The optical element package 23 is provided with a flange 23a on the front end side, and a lead portion 23b connected to a printed wiring board (not shown) on the base end side. Further, the optical element package 23 is provided with a light emitting unit (or light receiving unit) 23c at the center on the tip side.

The fixing tool 25 is made of metal, and includes a fixing tool main body 29 to which the rod lens 24 is fixed and a cover 30 screwed to the fixing tool main body 29.

The fixture body 29 has a through hole (first through hole) 29a formed from one end to the other end.
On the other end side, a concave portion 29b communicating with the through hole 29a is formed. The through hole 29a has a diameter that allows the rod lens 24 to be inserted, and the concave portion 29b has a diameter that fits with the flange 23a of the optical element package 23. A male screw 29c is formed concentrically with the recess 29b on the outer peripheral surface on the other end side of the fixture body 29. The rod lens 24 has a through-hole 29 such that one end face matches the concave bottom face 29d.
a and is adhered to the fixture body 29. Fixed
In the tool body 29, the rod lens 24 is inserted.
Step at the boundary between the outer peripheral portion of the cut portion and the portion of the male screw 29c.
(First step portion) 29e is formed.

The cover portion 30 has a cylindrical shape having a bottom portion 30a, and has an inner wall surface on which an external thread 2 of the fixing body 29 is provided.
A female screw to be screwed with 9c is formed. Also, the bottom 3
A hole 30b having a diameter into which the base end of the optical element package 23 can be inserted is formed at the center of Oa. The optical element package 23 is provided with a flange 23
The flange 23a is pressed against the bottom surface 29d of the concave portion by the cover 30 screwed to the fixture body 29, thereby being fixed to the fixture body 29. As a result, the rod lens 24 and the optical element package 23 are held by the fixture 25 with their optical axis centers aligned.

The housing 21 is formed of metal and is mounted on a housing 33 of the communication device. The housing 21 is formed with a through hole (a second through hole) 21 a extending from one end to the other end, and the diameter of one end of the through hole 21 a is large enough to fit the tip of the ferrule 22. The diameter at the other end is large enough to allow the fixture 25 to be inserted with play. See Figure 2 for details.
As is clear, the fixture 25 is inserted into the through hole 21a.
Has the largest diameter at the part where
First, the diameter is reduced in two stages. The largest diameter above
Step portion (second step portion) 2 of portion changing to next larger diameter
1e corresponds to the step portion 29e formed on the fixture body 29.
Have been allowed. A male screw 21b is formed concentrically with the through hole 21a on the outer periphery of one end of the housing 21. The ferrule 22 is inserted into the through hole 21a from one end of the housing 21 and covers the male screw 21b.
Is screwed in, the flange 22a is pressed against the end face 21c of the housing 21 and the housing 2
Fixed to 1. The fixing tool 25 is inserted into the through hole 21a from the other end of the housing 21, and the end face of the rod lens 24 is positioned so as to face the tip of the optical fiber core 27a. Are fixed to the wall surface of the through hole 21a with solder 37.

Next, the procedure for assembling the optical module will be described. First, the ferrule 22 is inserted into the through hole 21 a from one end of the housing 21, and the cover 35 is fastened and fixed to the housing 21. Next, the optical element package 23
And a fixture 25 for holding the rod lens 24 is inserted into the through-hole 21a from the other end of the housing 21 to adjust the optical axis and the distance to the ferrule 22, and then the cover 3
0 is soldered to the through hole 21a, and the assembling operation is completed.

In this assembling process, the optical element package 23 and the rod lens 24 are held by the fixture 25,
The fixing tool 25 can be moved with respect to the housing 21 within a range of a gap formed between the fixing tool 25 and the through hole 21a.
Therefore, by slightly moving the fixture 25 in the through hole 21a, the distance between the optical element package 23 and the ferrule 22 can be adjusted in addition to the optical axis adjustment. Further, the fixing tool 25 is configured to be fixed to the housing 21 by soldering, and since no force acts on the fixing tool 25, the fixing tool 25 whose optical axis has been adjusted and the distance has been adjusted may be shifted during fixing. Absent. Further, since the rod lens 22 is configured to be attached to the fixing tool 25, the flux or the like that has entered between the fixing tool 25 and the ferrule 22 at the time of soldering the fixing tool 25 removes the ferrule 22 from the housing 21. By opening one side of the through hole 21a, cleaning can be easily performed.

FIG. 3 is a view for explaining a second embodiment of the present invention.

The fixing device 25A of the present invention is composed of two members 251 and 252 formed in substantially the same shape. These members 251 and 252 have shapes formed by dividing a substantially cylindrical member having a space in which the optical element package 23 and the rod lens 24 can be mounted into two in the direction of the center of the circle. Members 251 and 2
A storage part 231 for the flange part 23 a of the optical element package 23 and a storage part 241 for the rod lens 24 are formed at 52.

The assembly of the fixing tool 25A is performed by the one member 2
51, the optical element package 23 is stored in the flange storage section 231.
Of the lens storage portion 24
After attaching the rod lens 24 to the member 1 and fixing the two to the member 251 with an adhesive, the mating surface A of the other member 252 is aligned with the mating surface B of the member 251 and both members 251 and 252 are bonded with an adhesive. Complete by fixing. Other configurations, operations, and effects are the same as those of the first embodiment.

In the above embodiment, the fixtures 25, 25A
Is fixed to the housing 21 by soldering, but may be fixed by laser welding or an adhesive.

[0029]

As described above, in the optical module of the present invention, since the optical element package and the rod lens are integrated via the fixture, the fixture is slightly moved when incorporated into the housing. The optical axis of the optical element package and the ferrule and the distance between them can be adjusted without changing the positional relationship between the optical element package and the rod lens. In addition, since the optical element package is provided on the fixture by the cover , the optical element package can be easily removed by the cover when the optical axis of the optical element package does not match the optical axis of the rod lens. Adjustment work is easy. Further, since the optical element package protrudes outside from the cover portion , the optical axis alignment and the distance adjustment work can be easily performed by gripping the protruded portion. Further, since the ferrule can be removed by the cover , even when the fixing tool is soldered to the housing, the flux generated at the time of soldering can be easily removed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view of an optical module according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the optical module.

FIG. 3 is a perspective view of a fixing device according to a second embodiment of the present invention.

FIG. 4 is a sectional view of a conventional optical module.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 ... Housing 21a ... 2nd through hole 22 ... Ferrule 23 ... Optical element package 24 ... Rod lens 25 ... Fixture 27 ... Optical fiber 29a ... 1st through hole

Claims (1)

(57) [Scope of request for utility model registration] 1. A first through-hole having a rod lens attached to one end of the first through-hole and a second end facing the end surface of one end of the rod lens. A concave portion in which the flange portion of the optical element package is buried is formed, a screw is formed in the outer peripheral portion, and a first step portion is formed at a boundary between the outer peripheral portion of the portion where the rod lens is attached and the screw portion. And a hole for covering the flange buried in the recess from the other end side of the fixture so as to wrap the flange, and a hole for projecting an optical element package connected to the flange is formed in the center. Was
A cover , a ferrule that holds the tip of the optical fiber, has a flange, and a fixing tool in which the ferrule is inserted from one end and a nut is coupled to the fixing body from the other end. A second through hole for adjusting the optical axis and the distance between the lens and the ferrule and inserting the ferrule is formed, a screw is formed on an outer peripheral portion on a side where the ferrule is inserted, and further when the fixing tool is inserted. A housing formed with a second step portion corresponding to the first step portion of the main body, and a flange of the ferrule serving as a stopper when the ferrule is inserted into the second through hole. And a cover for covering the flange.