JP4903112B2 - Optical path changing member and assembling method thereof - Google Patents

Description

  The present invention relates to an optical path changing member assembled at the tip of an optical fiber and an assembling method thereof. More specifically, the present invention relates to an optical path conversion member installed so that the optical fiber and the light input / output end are optically connected to a substrate provided with a light input / output end, and an assembly method thereof.

In recent years, an optical path conversion member assembled at a tip portion of an optical fiber wired along a substrate on which an optical element such as a light emitting element (semiconductor laser, etc.), a light receiving element (photodiode, etc.) is mounted, A method of installing so as to be optically connected to the element has been widely used (see, for example, Patent Documents 1 to 5).
This type of optical path conversion member is formed with a reflecting surface for changing the optical path in order to optically connect the optical fiber and the optical element. This reflective surface is required to have high molding accuracy.
There are two types of optical path conversion members: the internal reflection type, in which light strikes the reflective surface from the inside through the member body, and the external reflection type, in which light strikes the reflective surface from the outside of the member body. Is done.
Japanese Patent No. 3929968 JP 2002-90586 A US Pat. No. 6,491,447 US Pat. No. 6,1988,864 JP 2005-31556 A

However, in the optical path conversion member, if the structure of the optical path conversion member is complicated, it is difficult to increase the accuracy of the reflection surface, and thus an increase in cost for increasing the molding accuracy of the reflection surface is inevitable.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an optical path conversion member that can form a reflective surface with high accuracy and can reduce costs.

The present invention is an optical path conversion member that is assembled to the tip of an optical fiber and is installed facing a substrate provided with a light input / output end having an optical axis inclined with respect to the optical axis direction of the tip, An optical path changer in which a reflection surface for reflecting light from one of the optical fiber and the light input / output end toward the other and optically connecting them is formed by resin molding using a mold , and the optical path changer A member main body integrally formed with the optical path changing body by insert molding including at least a part, and the optical path changing body includes a substrate side when the optical path changing member is installed facing the substrate; A reflecting surface forming recess including the reflecting surface is formed on the surface to be formed, and an optical fiber insertion hole is formed in the reflecting surface forming recess to open the tip surface of the inserted optical fiber so as to face the reflecting surface. optical path conversion member has To provide.
The member main body is preferably formed so as to cover a distal end portion of the coating of the optical fiber.

The present invention is installed facing a substrate provided with a light input / output end having an optical axis inclined with respect to the optical axis direction of the tip of the optical fiber, and transmits light from one of the optical fiber and the light input / output end. A method of assembling an optical path conversion member having a reflection path that is reflected toward the other side and optically connecting them to each other and formed by resin molding using a mold , and a member body at the tip of the optical fiber The optical path changer has a reflecting surface forming recess, the reflecting surface is provided on one side of the inner surface of the reflecting surface forming recess, and the reflecting surface is opposed to the reflecting surface. An optical fiber insertion hole through which the tip of the optical fiber is inserted is opened on the other side of the inner surface of the formation recess, and the optical path changer having the tip of the optical fiber inserted through the optical fiber insertion hole , The optical path changing member on the substrate Facing the reflecting surface formed concave on the surface a substrate side when installed is placed in a mold to be formed, by insert molding using the mold, the member body, at least the optical path conversion member A method for assembling an optical path changing member that includes a part and is formed so as to be integrated with the optical path changing body is provided.

In the optical path conversion member of the present invention, an optical path conversion body that is a separate member from the member main body is used, and therefore the optical path conversion body can be formed independently of the member main body. Since the optical path changer has a simple structure, it is easy to improve the formation accuracy of the reflecting surface, and excellent optical characteristics can be obtained.
In addition, the optical path changer that is a part that requires high accuracy and the other part (member main body) that does not require so high accuracy can be manufactured using another mold corresponding to the required molding accuracy. Therefore, the manufacturing cost can be reduced as compared with the case where the entire optical path conversion member is integrally formed.
Furthermore, since the insert molding is employed, the optical fiber can be fixed by molding the member main body. Therefore, the process of bonding and fixing the optical fiber to the member main body is unnecessary, and the assembly process can be simplified.

FIG. 1 is a cross-sectional view showing an optical path conversion member 1 which is an embodiment of an optical path conversion member according to the present invention, and FIG. 2 is a plan view of the optical path conversion member 1.
The optical path conversion member 1 is assembled at the distal end portion 5 a of the optical fiber 5 and is installed facing the substrate 4.
Examples of the substrate 4 include a circuit substrate provided with various circuits for performing drive control of electronic components and the like, such as a photoelectric conversion circuit, a control processing unit, an optical signal processing circuit, an optical element driving circuit, and the like. The upper surface of the substrate 4 is a bonding surface 4a on which the optical path conversion member 1 is mounted.
The substrate 4 is provided with a light input / output end 6. As the light input / output end 6, a light emitting element such as a semiconductor laser (for example, laser diode: LD) or a light receiving element such as a photodiode (PD) can be used.
The optical axis direction of the light input / output end 6 is substantially perpendicular to the substrate 4. The optical axis direction of the light entrance / exit end 6 may be inclined with respect to the substrate 4 at an angle other than 90 °.

The optical fiber 5 is, for example, a multi-core optical fiber ribbon, and the tip portion 5 a is, for example, a bare optical fiber that is led out from the optical fiber 5. In the illustrated example, a plurality of front end portions 5 a led out from the optical fiber ribbon are arranged side by side along the bottom surface (mounting surface 1 a) of the optical path conversion member 1.
The optical fiber to which the optical path changing member of the present invention can be applied is not limited to the illustrated example, and various configurations such as a single-core optical fiber and an optical fiber can be employed.
As the optical fiber, for example, an all-quartz standard SM type optical fiber or GI type optical fiber is suitable, and an optical fiber having a diameter of 80 μm, which is smaller than the standard 125 μm diameter, can be used.
In the following description, the tip direction (left side in FIG. 1) of the tip part 5a of the optical fiber 5 may be referred to as the front, and the opposite direction (right side in FIG. 1) may be referred to as the rear. The front-rear direction here is the optical axis direction of the distal end portion 5 a of the optical fiber 5. The optical axis direction of the distal end portion 5a is the extending direction of the optical fiber 5. Further, the mounting surface 1a side may be referred to as “down” and the opposite surface side (upper surface 1b side) may be referred to as “up”.

The optical path conversion member 1 includes an optical path conversion body 2 and a member main body 3 formed integrally with the optical path conversion body 2.
The optical path changer 2 is formed in, for example, a block shape, and a reflection surface formation recess 7 (reflection surface formation space) is formed on the bottom surface 2a (surface on the substrate 4 side). In the illustrated example, the reflecting surface forming recess 7 is formed in a groove shape along a direction substantially perpendicular to the front-rear direction (vertical direction in FIG. 2; vertical direction in FIG. 1).

As shown in FIG. 1, the front surface of the inner surface of the reflecting surface forming recess 7 is a reflecting surface 8.
The reflecting surface 8 is formed so as to be inclined with respect to the optical axis direction of the optical fiber 5 (left-right direction in FIG. 1) and the optical axis direction of the light input / output end 6 (vertical direction in FIG. 1). It is formed to face 5b (tip surface). In the illustrated example, the reflecting surface 8 is inclined backward as it goes in the depth direction of the reflecting surface forming recess 7.
The reflecting surface 8 may be a flat surface or a curved concave surface that functions as a lens. To function as a lens means to collect light from the tip 5a (or light input / output end 6) and direct it toward the light input / output end 6 (or tip 5a).
The reflective surface 8 is located above the light input / output end 6 and faces the light emitting surface or the light receiving surface of the light input / output end 6 when the optical path changing member 1 is disposed on the substrate 4.
The reflection efficiency can be increased by polishing the reflecting surface 8 as necessary. A metal film may be formed on the reflecting surface 8 by vapor deposition or the like.

The reflecting surface 8 reflects the light emitted from the end surface 5b of the tip portion 5a and directs it toward the light input / output end 6, or reflects the light emitted from the light input / output end 6 and directs it toward the end surface 5b of the tip portion 5a. Thus, the tip portion 5 a and the light input / output end 6 are optically connected by the optical path 9.
A portion of the optical path 9 between the reflecting surface 8 and the light input / output end 6 coincides with the optical axis direction of the light input / output end 6 and is inclined with respect to the optical axis direction of the distal end portion 5a. In the illustrated example, the optical axis direction of the distal end portion 5a is parallel to the extending direction of the circuit board 1, and the optical path 9 between the reflecting surface 8 and the light input / output end 6 is in the optical axis direction of the distal end portion 5a. It is perpendicular to it.

In the rear part of the optical path changer 2, an optical fiber insertion hole 10 is formed along the front-rear direction. The rear end of the optical fiber insertion hole 10 is opened at the rear surface of the optical path changer 2.
The same number of optical fiber insertion holes 10 as the number of tip portions 5a can be formed in the vertical direction in FIG.
The optical fiber insertion hole 10 is inserted into the distal end portion 5 a and the end surface 5 b (front end surface) is disposed in the reflection surface forming recess 7.
The tip 5a may be bonded to the inner surface of the optical fiber insertion hole 10 with an adhesive.

  As the optical path changer 2, a resin suitable for precision molding can be used. For example, epoxy resin, PPS (polyphenylene sulfide) resin, LCP (liquid crystal polymer) resin, and the like are suitable. The optical path changer 2 can be molded by a general-purpose resin molding method (such as injection molding or compression molding).

The member main body 3 includes the optical path changing body 2 and is integrally formed by insert molding. The member body 3 is preferably made of a transparent material. For example, a polycarbonate resin, a modified polyolefin resin, an epoxy resin, a polyethyleneimine (PEI) resin, an acrylic resin, or the like can be used.
The member body 3 can be formed so that at least a portion through which the optical path 9 passes is made of a transparent material, and the whole is preferably made of a transparent material.

  In the illustrated example, the member main body 3 is formed so as to embed the entire optical path conversion body 2, but it may be configured to include at least a part of the optical path conversion body 2. For example, a part of the optical path changing body 2 (for example, the bottom surface 2a may be exposed to the mounting surface 1a.

In the illustrated example, the member main body 3 is formed so as to cover the distal end portion of the coating 5 c of the optical fiber 5. In this structure, the member main body 3 can be firmly joined to the optical fiber 5, and durability can be enhanced.
When this structure is employed, the coating 5c can be formed of a heat resistant material. As a result, it is possible to prevent the coating 5c from being adversely affected by heat when the member body 3 is molded. Further, the portion of the optical fiber 5 covered with the member main body 3 can be covered with a coating made of a heat-resistant material or a heat insulating material.
The member main body 3 can be provided with a positioning structure (not shown) such as a fitting unevenness for positioning with respect to the substrate 4.
On the lower surface (mounting surface 1 a) of the member main body 3, lens means (not shown) can be formed integrally with the member main body 3 at a position facing the light input / output end 6. The lens means collects the reflected light from the reflecting surface 8 and directs it toward the light input / output end 6, or condenses the emitted light from the light entering / exiting end 6 and directs it toward the reflecting surface 8.
On the lower surface (mounting surface 1a) of the member main body 3, an AR (Anti Reflection) coat can be formed in a portion where light enters and exits.

Next, assembly of the optical path conversion member 1 will be described.
As shown in FIGS. 3 and 4, the distal end portion 5 a of the optical fiber 5 is inserted into the optical fiber insertion hole 10 of the optical path changing body 2 from the rear and protruded into the reflecting surface forming recess 7.
The optical path changer 2 is preferably fixed to the optical fiber insertion hole 10 with an adhesive or the like.
Next, as shown in FIG. 5, the optical path conversion body 2 is accommodated in a mold 11 having an inner surface shape corresponding to the member main body 3, and the member main body 3 is insert-molded by filling the mold 11 with the resin. To do.
Next, as shown in FIG. 6, the mold 11 is removed to obtain the optical path changing member 1 shown in FIGS.

In the optical path conversion member 1, since the optical path conversion body 2, which is a separate member from the member main body 3, is used, the optical path conversion body 2 can be formed independently of the member main body 3. Since the optical path changer 2 has a simple structure, it is easy to improve the formation accuracy of the reflecting surface 8.
On the other hand, in the case where the entire optical path conversion member is integrally formed, if the other structure is complicated, it is difficult to accurately form the reflecting surface. The other structure is, for example, a structure for positioning the optical path conversion member on the substrate or an optical fiber insertion hole.
In the optical path conversion member 1, since the reflection surface 8 can be formed with high accuracy, the reflection efficiency on the reflection surface 8 can be increased, and excellent optical characteristics can be obtained.

In the optical path conversion member 1, the optical path conversion body 2 (particularly the reflecting surface 8 on the inner surface thereof) which is a part that requires particularly high molding accuracy, and other parts (member body) that do not require as high accuracy as the optical path conversion body 2 3) can be manufactured by using another mold corresponding to the required molding accuracy, and therefore, the manufacturing cost can be reduced as compared with the case where the entire optical path conversion member is integrally molded.
In particular, in the case of increasing the number of cores, the number of optical fiber insertion holes 10 is increased and high accuracy is required. Therefore, when the entire optical path conversion member is formed integrally, the manufacturing cost of the mold becomes very high. In the optical path conversion member 1, since the cost required for mold production can be suppressed, it is possible to cope with the increase in the number of cores.
Moreover, in the optical path conversion member 1, since the optical path conversion body 2 and the member main body 3 can be shape | molded independently, a change of a specification is easy. For example, when changing the specifications related to the optical path changer 2, only the design of the optical path changer 2 needs to be changed.

  Since the optical path conversion member 1 employs insert molding, the optical fiber 5 can be fixed by molding the member body 3. Therefore, the process of adhering and fixing the optical fiber 5 to the member body 3 is not necessary, and the assembly process can be simplified.

  Moreover, since the optical path conversion member 1 uses the optical path conversion body 2 which is a separate member from the member main body 3, the optical fiber insertion hole 10 is shorter than the case where the entire optical path conversion member is integrated. The protruding length of the tip 5a to the formation recess 7 can be determined with high accuracy. Therefore, the distance between the end surface 5b of the tip 5a and the reflecting surface 8 can be set accurately.

  Further, in a general optical path conversion member, the distal end portion is inserted by inserting the distal end portion of the optical fiber into an optical fiber insertion hole formed in the optical path conversion member and filling the concave portion with an adhesive in a state of protruding into the concave portion. To fix. For this reason, peeling of the adhesive or formation of microvoids in the adhesive may occur. On the other hand, since the optical path conversion member 1 employs insert molding, the optical fiber 5 can be fixed by molding the member body 3, so that a large amount of adhesive is unnecessary, and such a problem hardly occurs.

It is sectional drawing which shows an example of the optical path changing member which concerns on this invention. It is a top view which shows the optical path changing member shown in FIG. It is process drawing which shows the manufacturing process of the optical path changing member shown in FIG. It is process drawing following a previous figure. It is process drawing following a previous figure. It is process drawing following a previous figure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Optical path conversion member, 2 ... Optical path conversion body, 3 ... Member main body, 4 ... Board | substrate, 5 ... Optical fiber, 5a ... Tip part, 5b ... End surface (tip Surface), 6... Light entry / exit end, 7... Reflection surface forming recess, 8... Reflection surface, 10 .. optical fiber insertion hole, 11.

Claims (3)

The optical fiber (5) is assembled at the front end (5a) and is placed facing the substrate (4) provided with a light input / output end (6) having an optical axis inclined with respect to the optical axis direction of the front end. An optical path changing member,
An optical path changer (2) in which a reflecting surface (8) for reflecting light from one of the optical fiber and the light input / output end toward the other and optically connecting them is formed by resin molding using a mold ; ,
A member main body (3) integrally formed with the optical path changing body by insert molding including at least a part of the optical path changing body,
In the optical path changer, a reflection surface forming recess (7) is formed on the surface that becomes the substrate side when the optical path conversion member is placed facing the substrate, and one side of the inner surface of the reflection surface forming recess is formed. The optical fiber insertion hole (10) through which the distal end portion (5a) of the optical fiber is inserted is opened on the other side of the inner surface of the reflection surface forming recess so as to face the reflection surface. optical path conversion member, characterized in that there.   2. The optical path conversion member according to claim 1, wherein the member main body is formed so as to cover a distal end portion of the coating (5 c) of the optical fiber. The optical fiber (5) is placed facing a substrate (4) provided with a light input / output end (6) having an optical axis inclined with respect to the optical axis direction of the tip (5a) of the optical fiber (5), and the optical fiber and the optical input / output An optical path changer (2) in which a reflecting surface (8) for reflecting light from one of the ends toward the other and optically connecting them is formed by resin molding using a mold, and a member main body (3) An optical path changing member having
The optical path changer is formed with a reflecting surface forming recess (7), a reflecting surface is provided on one side of the inner surface of the reflecting surface forming recess, and the reflecting surface is formed so as to face the reflecting surface. An optical fiber insertion hole (10) through which the tip (5a) of the optical fiber is inserted is opened on the other side of the inner surface of the recess,
The reflective surface forming recess is formed on the surface that becomes the substrate side when the optical path conversion member having the optical fiber insertion hole inserted through the optical fiber insertion hole is disposed facing the substrate. As described above, the member main body is formed so as to be integrated with the optical path changing body by including at least a part of the optical path changing body by insert molding using the mold (11). A method for assembling an optical path changing member.

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