Lead frame, optical coupling part using lead frame, and manufacturing method of optical coupling part

When a resin 59 to form a molded body 20 is poured and a lead frame 30 is attached to a front end face 21 of the molded body 20 by insert molding, protective leads 32 provided on both outsides of a lead pattern 31 of the lead frame 30 moderate the flow of the resin 59 and the force acting on the lead pattern 31 is decreased, so that misregistration of the lead pattern 31 can be prevented. Accordingly, the inserted and molded lead frame 30 can be wired on the front end face 21 of the molded body 20 for easily accomplishing three-dimensional electric wiring.

TECHNICAL FIELD

The present disclosure to a lead frame, an optical coupling part using the lead frame, and a manufacturing method of the optical coupling part and, for example, relates to a lead frame for making electric connection to a photoelectric conversion unit, an optical coupling part using the lead frame, and a manufacturing method of the optical coupling part.

RELATED ART

Demands for speeding up and a larger capacity also grow for a router on a network node and further a home information appliance with the development of a broadband. To meet the demands, introduction examination of optical interconnection for executing E/O conversion in an input/output portion of electric transmission and performing high-speed and large-capacity transmission utilizing the wideband characteristic of an optical fiber moves forward. An art for coupling photoelectric conversion elements (light-emitting element and light-receiving element) and an optical fiber in an E/O conversion portion is disclosed. (For example, refer to Patent Document 1: Japanese Patent Unexamined Publication No. 2005-43622(FIG. 1).)

As shown inFIG. 6, an optical coupling part100described in Patent Document 1 has a molded body104for mechanically holding an optical fiber101in a holding hole102with an optical input/output end face103of the optical fiber101exposed onto a principal plane, and electric wiring105is provided on the principal plane of the molded body104. A photosemiconductor107is provided through an insulating film106ahead of the optical fiber101and is connected to the electric wiring105by a bump108.

In a manufacturing method of the optical coupling part described in Patent Document 1, Patent Document 1 describes that the flexibility of the coupling position is enhanced as the optical coupling part has the electric wiring formed over the top of the principal plane and the top of a side face of the molded body104. However, it is difficult to form such three-dimensional electric wiring continuously on the object surface.

SUMMARY

Embodiments of the present invention provide a lead frame to make it possible to easily accomplish three-dimensional electric wiring, an optical coupling part using the lead frame, and a manufacturing method of the optical coupling part.

According to one or more embodiments of the present invention, there is provided a lead frame inserted and molded into a molded body for allowing a plurality of optical fibers to be inserted and exposed, the lead frame comprising: a lead pattern wired on a front end face of the molded body for making electric connection to a photoelectric conversion unit placed facing the optical fibers; and protective leads which are provided at both outside positions of the lead pattern and protects the lead pattern.

In the described lead frame, when a resin to form the molded body is poured and the lead frame is attached to the front end face of the molded body by insert molding, the protective leads provided on both outsides of the lead pattern of the lead frame moderate the flow of the resin and the force acting on the lead pattern is decreased, so that misregistration and deformation of the lead pattern can be prevented. Accordingly, the inserted and molded lead frame can be wired on the front end face of the molded body for easily accomplishing three-dimensional electric wiring.

Preferably, in the lead frame according to the present invention, the protective leads are provided in a state of a beam with both ends supported on the lead frame.

In the described lead frame, the protective leads provided on both outsides of the lead pattern are supported in the state of the beam with both ends supported on the lead frame, so that a sufficient strength can be given to the protective leads. Thus, the flow of the resin poured when the molded body is molded can be moderated for protecting the lead pattern and a move and deformation of the lead pattern can be prevented reliably.

According to the present invention, there is provided an optical coupling part comprising: a molded body for allowing a plurality of optical fibers to be inserted and exposed; a photoelectric conversion unit placed facing the optical fibers; a lead frame inserted and molded into the molded body, the lead frame having a lead pattern, which is wired on a front end face of the molded body and makes electric connection to the photoelectric conversion unit, and protective leads, which are provided at both outside positions of the lead pattern in the lead frame and protects the lead pattern.

In the described optical coupling part, when the molded body is molded, the lead frame is attached to the front end face of the molded body by insert molding. At this time, when a resin to form the molded body is poured, the protective leads provided on both outsides of the lead pattern of the lead frame moderate the flow of the resin and the force acting on the lead pattern is decreased, so that misregistration of the lead pattern can be prevented. Accordingly, the inserted and molded lead frame can be wired on the front end face of the molded body for easily accomplishing three-dimensional electric wiring.

According to the present invention, there is provided a manufacturing method of an optical coupling part, comprising: preparing a lead frame having a lead pattern for making electric connection to a photoelectric conversion unit placed facing a plurality of optical fibers and protective leads provided on both outsides of the lead pattern; and executing insert molding of the lead frame into a front end face of a molded body for allowing the optical fibers to be inserted and exposed, wherein when insert molding of the lead frame into the molded body is executed, the lead pattern is protected by the protective leads.

In the described manufacturing method of the optical coupling part, when the molded body is molded, the lead frame is attached to the front end face of the molded body by insert molding. When a resin to form the molded body is poured, the protective leads provided on both outsides of the lead pattern of the lead frame moderate the flow of the resin and the force acting on the lead pattern is decreased, so that the lead pattern can be protected for preventing misregistration thereof. Accordingly, the inserted and molded lead frame can be wired on the front end face of the molded body for easily accomplishing three-dimensional electric wiring.

One or more embodiments of the present invention may include one or more the following advantages. For example, since the protective leads are provided on both outsides of the lead pattern of the lead frame, when a resin to form the molded body is poured and the lead frame is attached to the front end face of the molded body by insert molding, the protective leads moderate the flow of the resin and the force acting on the lead pattern is decreased. Accordingly, misregistration of the lead pattern can be prevented and the inserted and molded lead frame can be wired on the front end face of the molded body for easily accomplishing three-dimensional electric wiring.

Other features and advantages may be apparent from the following detailed description, the accompanying drawings and the claims.

DETAILED DESCRIPTION

An embodiment according to the present invention will be discussed in detail based on the accompanying drawings.

FIG. 1is a perspective view showing a molded body of an optical coupling part using a lead frame of the present invention.FIG. 2is a sectional view showing the front of the optical coupling part using the lead frame of the present invention.FIG. 3Ais a plan view showing the lead frame according to the present invention.FIG. 3Bis a plan view showing a lead frame in a related art.FIG. 4is a sectional view showing a mold for molding a molded body of an optical coupling part into which the lead frame according to the present invention is inserted and molded.FIG. 5is a plan view showing a flow of resin poured for molding the molded body.

As shown inFIGS. 1 and 2, an optical coupling part10is provided with a lead frame30inserted and molded into a molded body20for allowing a plurality of optical fibers11to be inserted and exposed. The lead frame30has a lead pattern31bent and wired on a front end face21of the molded body20and exposed on a side face22continuous to the front end face21, and supplies power to a photoelectric conversion unit40placed facing the optical fibers11. A protective lead32for protecting the lead pattern31is provided at both outside positions of the lead pattern31in the lead frame30.

As shown inFIG. 2, the optical coupling part10has a main body10aof the molded body20shaped roughly like a rectangular parallelepiped and the photoelectric conversion unit40attached to the front end face21of the main body10a. An electric wiring section23is provided over the front end face21of the molded body10aand exposed on a side face22(top face inFIGS. 1 and 2) continuous to the front end face21. For example, an optical fiber insertion hole24for allowing a front end face11bof the optical fiber11to be exposed is made at the position of each short electric wiring part23ainFIG. 1. Long wiring parts23bare provided at both ends of the electric wiring section23and between the short electric wiring parts23a.

On the other hand, as shown inFIG. 2, the photoelectric conversion unit40is provided with a photoelectric conversion element41and an active layer42is positioned facing the optical fiber insertion hole24of the front end face21of the main body10a. The photoelectric conversion unit40is provided with a drive electrode43for supplying power to the active layer42or sending a signal from the active layer42. When the photoelectric conversion unit40is attached to the front end face21of the main body10a, the drive electrode43is brought into contact with the electric wiring section23of the main body10a.

Accordingly, when the optical coupling part10is mounted on a board (not shown), power is supplied through the electric wiring section23to the photoelectric conversion element41, so that a light signal can be emitted to the optical fiber11and a light signal from the optical fiber11can be received and a signal can be transmitted.

FIG. 3Ashows the lead frame30according to the present invention. The lead frame30has a lead pattern31forming the above-described electric wiring section23like a lead frame30B used in a related art shown inFIG. 3B. The lead pattern31has short leads31aforming short electric wiring parts23aand long leads31bforming the long wiring parts23b. The lead frame30is notched between the leads31aand31bto form a space33.

At both ends of the lead pattern31, the protective lead32which does not become the electric wiring section23is provided in addition to a lead pattern31of the lead frame30B in the related art shown inFIG. 3B. The protective leads32are provided in a state of a beam with both ends supported on the lead frame30and has a sufficient strength. A positioning hole34for positioning to insert the lead frame30into a proper position in manufacturing the optical coupling part10is made in four corners of the lead frame30.

The lead pattern31, the protective leads32, the positioning holes34, and the like are formed in the lead frame30by punching of etching, press, etc., for example.

As shown inFIG. 4, a mold50for manufacturing the molded body20into which the lead frame30is inserted has an upper mold51and a lower mold52and the upper and lower molds51and52are combined to form a cavity53for forming the main body10aof the optical coupling part10between the upper and lower molds. Ahead of the upper and lower molds51and52(at the left inFIG. 4), a second slide core56for forming the molded body20with the front end face21allowing tip parts11aof the optical fibers11(seeFIG. 2) to be exposed is placed facing a first slide core55and positioned by positioning pins58.

The first slide core55having a core pin54to form the molded body20with the optical fiber insertion holes24to allow the optical fibers11to be inserted (seeFIGS. 1 and 2) is inserted between the upper and lower molds51and52. A convex part57for adjusting the height of the first slide core55is provided at the center of the lower mold52so that the upper and lower positions can be adjusted in a nest structure. The convex part57adjusts the height of the first slide core55and supports the first slide core55from below at the resin pouring time and forms an adhesive pouring port (not shown) for pouring an adhesive59when the optical fibers11are fixed in the manufactured optical coupling part10.

The second slide core56is provided with a positioning hole56afor positioning the core pin54and the tip of the core pin54is inserted into the positioning hole56a, whereby the core pin54can be positioned accurately in the cavity53. The positioning pins58to which the second slide core56is attached pass through the positioning holes34of the lead frame30for precisely positioning the lead frame30at the proper position.

Next, a manufacturing method of the optical coupling part will be discussed.

The manufacturing method of the optical coupling part10is to execute insert molding of a lead frame30having a lead pattern31for making electric connection to a photoelectric conversion unit40placed facing optical fibers11on a front end face21of a molded body20for allowing a plurality of optical fibers11to be inserted and exposed and a side face22continuous to the front end face21. To execute insert molding of the lead frame30into the molded body20, the lead pattern31for power supply is protected by the protective leads32provided on both outsides of the lead pattern31.

That is, both molds51and52are combined and the lead frame30is positioned by positioning pins58provided on front end faces51aand52aof the upper mold51and the lower mold52as shown inFIG. 4. A convex part57is adjusted to a predetermined height, a first slide core55is inserted, further a second slide core56is attached, and a mold50is set. Then, a resin59is poured into a cavity53in the mold50and insert molding of the lead frame30is executed to form a molded body20. At this time, the resin59poured into the cavity53flows forward (downward inFIG. 5) from the side of the first slide core55and flows to the center along the lead frame30as shown inFIG. 5. At this time, the protective leads32provided on both outsides of the lead pattern31of the lead frame30moderate the flow of the resin, so that the force acting on leads31aand31bof the lead pattern31to form an electric wiring section23can be decreased. Thus, misregistration and deformation of the leads31aand31bcan be prevented and insert molding of the lead frame30can be executed precisely at the proper position.

When the resin59is poured and the insert molding of the lead frame30is complete, the first slide core55and the second slide core56are moved away from each other and then the molded body20is taken out from the mold50. An unnecessary portion of the lead frame30inserted and molded into the front end face21of the molded body20is cut and removed.

Then, the photoelectric conversion unit40is attached to the front end face21of the molded body20so that an active layer42of a photoelectric conversion element41is positioned on the front of optical fiber insertion holes24of the molded body20and a drive electrode43comes in contact with the electric wiring section23on the side of a main body10a, namely, a lead pattern31of the lead frame30, as shown inFIG. 2.

In the optical coupling part10thus manufactured, the front end face21of the main body10ais slantingly cut for improving the transmission characteristic.

As described above, according to the lead frame, the optical coupling part using the lead frame, and the manufacturing method of the optical coupling part according to the present invention, when the resin59to form the molded body20is poured and the lead frame30is attached to the front end face21of the molded body20by insert molding, the protective leads32provided on both outsides of the lead pattern31of the lead frame30moderate the flow of the resin59and the force acting on the lead pattern31is decreased, so that misregistration and deformation of the lead pattern31can be prevented. Accordingly, the inserted and molded lead frame30can be wired on the front end face21of the molded body20for easily accomplishing three-dimensional electric wiring.

The lead frame, the optical coupling part using the lead frame, and the manufacturing method of the optical coupling part of the present invention are not limited to those in the specific embodiment described above and appropriate modifications, improvements, etc., are possible.

For example, in the embodiment described above, the protective leads32are provided each one on each of both outsides of the lead pattern31by way of example, but a plurality of protective leads32can also be placed on each outside. The width of the protective lead32may be equal to or may be different from that of the lead31a,31bof the lead pattern31. For example, the width of the protective lead32may be larger than that of the lead31a,31bof the lead pattern31. In this case, the moderation of the flow of the resin by the protective leads becomes more effective.

Further, in the embodiment described above, the leads31aare provided on the upper and lower portions of the front end face21of the molded body20, but the leads31amay be provided only one of the upper or lower portion of the front end face21. However, when the leads31aare provided on the upper and lower portions of the front end face21as described above, both of side surfaces22of optical coupling part10(inFIG. 1, the upper side surface22and the lower surface opposed to the upper side surface22) can be used as a surface to be mounted on the board.

As described above, in the lead frame, the optical coupling part using the lead frame, and the manufacturing method of the optical coupling part according to the present invention, since the protective leads are provided on both outsides of the lead pattern of the lead frame, when a resin to form the molded body is poured and the lead frame is attached to the front end face of the molded body by insert molding, the protective leads moderate the flow of the resin and the force acting on the lead pattern is decreased. Accordingly, misregistration and deformation of the lead pattern can be prevented and the inserted and molded lead frame can be wired on the front end face of the molded body, whereby three-dimensional electric wiring can be easily accomplished, and the present invention is useful as a lead frame for supplying power to a photoelectric conversion unit, an optical coupling part using the lead frame, a manufacturing method of the optical coupling part, etc.