JP5879810B2 - Optical module and cable with optical module - Google Patents

Description

  The present invention relates to an optical module provided at an end of a cable incorporating a plurality of optical fibers and a cable with an optical module.

  In order to cope with an increase in the amount of information associated with the rapid spread of the Internet and multimedia, development of an optical interconnection technology using an optical signal for signal transmission between devices of a processing apparatus is in progress.

  In optical interconnection technology, in addition to optical connections, electrical connections such as low-speed signals, power supply, and ground are often required, so optoelectric composite cables with built-in optical fibers and wires are widely used. ing. When a plurality of optical fibers are used, a ribbon fiber in which a plurality of optical fibers are arranged in parallel is used in order to facilitate handling during connection.

  There is a conventional optical module as shown in FIG.

  The optical module 61 shown in FIG. 6 is provided at a case 11 to which the cable 10 is connected, a substrate 12 accommodated in the case 11, an end of the substrate 12, and exposed from the case 11 to the outside. And an electrical connector 13 that is electrically connected to a receptacle of an external electrical device (not shown) and a ribbon fiber 15 that is mounted on the substrate 12 via the FPC connector 14 and that extends from the cable 10 into the case 11. And a flexible substrate 16 to which the end of each is connected.

  Although not shown, an optical waveguide is formed on one surface of the flexible substrate 16 to which the core of each optical fiber of the ribbon fiber 15 is optically connected.

  An optical element 17 and an IC 18 are mounted on the other surface of the flexible substrate 16. The optical element 17 is optically connected to the core of each optical fiber of the ribbon fiber 15 via an optical waveguide, and is electrically connected to the electrical connector 13 via the flexible substrate 16 and the substrate 12. .

  When a light emitting element (surface light emitting element) is used as the optical element 17, that is, in the optical module 61 on the transmission side, an electrical signal input from an external electrical device via the electrical connector 13 is converted into an optical signal by the optical element 17. And output to the ribbon fiber 15.

  On the other hand, when a light receiving element (surface light receiving element) is used as the optical element 17, that is, in the optical module 61 on the receiving side, the optical signal input from the ribbon fiber 15 is converted into an electrical signal by the optical element 17, and an electrical connector is used. 13 to an external electrical device.

  In this optical module 61, when the cable 10 is bent and stretched, the length of the ribbon fiber 15 extending from the end of the cable 10 changes. In order to cope with this change, the ribbon fiber 15 in the case 11. The extra length of the ribbon fiber 15 is accommodated in the case 11.

  In addition, there exists patent document 1 as prior art document information relevant to invention of this application.

JP 2010-10254 A

  By the way, since the ribbon fiber 15 has a plurality of optical fibers arranged in parallel, the ribbon fiber 15 cannot be bent in the optical fiber arrangement direction (referred to as the major axis direction). Therefore, when the extra length of the ribbon fiber 15 is accommodated in the case 11, it is necessary to bend the ribbon fiber 15 in a direction perpendicular to the arrangement direction of the optical fibers (referred to as a minor axis direction). However, even when the ribbon fiber 15 is bent in the minor axis direction, the optical fiber is broken unless the radius of curvature is increased to some extent.

  Further, the size of the case 11 is determined by the standard, and it is difficult to ensure a sufficiently large distance between the case 11 and the substrate 12. Therefore, in order to accommodate a sufficient extra length between the case 11 and the substrate 12, the direction in which the ribbon fiber 15 is bent is inevitably parallel to the surface of the substrate 12. Therefore, the ribbon fiber 15 is introduced into the case 11 so that the major axis direction is perpendicular to the surface of the substrate 12, and bent in the minor axis direction in the same plane parallel to the surface of the substrate 12, It is necessary to accommodate the extra length of the ribbon fiber 15 in the case 11 by turning the ribbon fiber 15 once or bending it into an S shape.

  However, the flexible substrate 16 to which the ribbon fiber 15 is connected is arranged in parallel to the surface of the substrate 12. In the connection portion with the flexible substrate 16, it is necessary to make the major axis direction of the ribbon fiber 15 parallel to the flexible substrate 16. After that, it is necessary to twist the ribbon fiber 15 by 90 ° in order to connect to the flexible substrate 16.

  The present invention has been made in view of the above circumstances, and an optical module and an optical module that can accommodate an extra length of a ribbon fiber in a case and can be connected to a flexible substrate without twisting the ribbon fiber. The purpose is to provide a cable.

  The present invention has been devised to achieve the above object, and is an optical module provided at an end of a cable incorporating a plurality of optical fibers, the case to which the cable is connected, And a flexible substrate formed on the substrate and formed with an optical waveguide to which the core of the optical fiber is optically connected, and the plurality of optical fibers includes a plurality of optical fibers. A ribbon fiber in which the optical fibers of the book are arranged in parallel is extended from the cable into the case, and the flexible substrate has a vertical portion bent in a direction perpendicular to the surface of the substrate, An optical module configured to connect an end portion of the ribbon fiber to a vertical portion.

  ADVANTAGE OF THE INVENTION According to this invention, the optical module and cable with an optical module which can accommodate the surplus length of a ribbon fiber in a case, and can be connected to a flexible substrate without twisting a ribbon fiber can be provided.

It is a figure which shows the cable with an optical module using the optical module which concerns on one embodiment of this invention, (a) is a perspective view, (b) is a part of the 1B-1B sectional view taken on the line. It is the perspective view seen from the other direction of the cable with an optical module of FIG. It is a top view of the cable with an optical module of FIG. It is a cross-sectional view of the ribbon fiber used for the optical module of FIG. In the optical module of FIG. 1, it is a figure explaining the structure of the connection part of a ribbon fiber and a flexible substrate. It is a top view of the conventional optical module.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1A and 1B are diagrams showing a cable with an optical module using the optical module according to the present embodiment, in which FIG. 1A is a perspective view and FIG. 1B is a part of a cross-sectional view taken along line 1B-1B. 2 is a perspective view seen from the other direction, and FIG. 3 is a top view thereof.

  As shown in FIGS. 1 to 3, the optical module 1 is provided at the end of a cable 10 incorporating a plurality of optical fibers (ribbon fiber 15 in the figure), and is connected to a receptacle of an external electric device (not shown). An electrical signal from an external electrical device is converted into an optical signal and output to the ribbon fiber 15, or an optical signal from the ribbon fiber 15 is converted into an electrical signal and output to an external electrical device. is there.

  The cable 10 incorporates a plurality of optical fibers in a state of being scattered along the longitudinal direction. The plurality of optical fibers are drawn from the end of the cable 10 in a ribbon fiber state in which a plurality of optical fibers are arranged in parallel. The cable 10 may incorporate a plurality of optical fibers in the state of ribbon fibers along the longitudinal direction.

  As shown in FIG. 4, the ribbon fiber 15 is formed by arranging a plurality of optical fibers 15a in parallel and covering the periphery with a batch coating 15b. In FIG. 4, four ribbon fibers 15 in which four optical fibers 15 a are arranged in parallel are shown, but the number of optical fibers 15 a is not limited to this. Hereinafter, the arrangement direction of the optical fibers 15a of the ribbon fiber 15 is referred to as a major axis direction, and the direction perpendicular to the arrangement direction of the optical fibers 15a is referred to as a minor axis direction.

  The optical module 1 is provided at a case 11 to which a cable 10 is connected, a substrate (printed substrate) 12 accommodated in the case 11, and an end of the substrate 12, and is provided so as to be exposed from the case 11 to the outside. And an electrical connector 13 that is electrically connected to a receptacle of an external electrical device (not shown) and a ribbon fiber 15 that is mounted on the substrate 12 via the FPC connector 14 and that extends from the cable 10 into the case 11. The flexible substrate (flexible printed circuit board) 16 to which the edge part of this is connected is provided.

  As the case 11, it is desirable to use a metal case in order to improve heat dissipation. In FIG. 1A, FIG. 2, and FIG. 3, the upper portion of the case 11 is omitted. A boot 10 a for protecting the cable 10 is provided around the connection portion of the cable 10 to the case 11.

  The substrate 12 is a rigid substrate made of glass epoxy, for example, and electrical wiring (not shown) is formed on the front and back surfaces thereof. In the present embodiment, the substrate 12 is formed by bonding the back surfaces of two rigid substrates each having an electrical wiring on the front surface. Electrodes 12a are aligned and formed at the end of the board 12 on the side where the electrical connector 13 is provided.

  The electrical connector 13 includes a plurality of pin terminals (not shown) that are electrically connected to each of the pin terminals provided on the receptacle when connected to the receptacle of the external electrical device. The electrically connected connection terminal 13a is exposed to the outside. By electrically connecting the connection terminals 13a to the electrodes 12a of the substrate 12 by soldering or the like, the substrate 12 and the electrical connector 13 are electrically connected.

  In the present embodiment, a case will be described in which an HDMI plug compliant with the HDMI (registered trademark) (High-Definition Multimedia Interface) standard is used as the electrical connector 13. In this case, the case 11 is formed in a size conforming to the HDMI standard. The module-equipped cable 100 in which the optical module 1 is provided at both ends of the cable 10 is generally called an HDMI cable.

  The flexible substrate 16 includes a film substrate 16a made of polyimide or the like, and an optical waveguide 19 formed on one surface of the film substrate 16a and optically connected to the core of each optical fiber 15a of the ribbon fiber 15. ing. The optical waveguide 19 is a so-called polymer waveguide made of resin, and the flexible substrate 16 has flexibility as a whole.

  Electrical wiring (not shown) is formed on the other surface of the film substrate 16a, and the optical element 17 and the IC 18 are mounted on the electrical wiring. A 45 ° mirror 17a for converting the optical axis by 90 ° is formed on the core 19a of the optical waveguide 19 at a position facing the optical device 17, and the optical device 17 and the optical waveguide 19 are passed through the 45 ° mirror 17a. The core 19a is optically connected.

  As the optical element 17, a surface light emitting element such as VCSEL (Vertical Cavity Surface Emitting Laser) or a surface light receiving element such as PD (Photo Diode) is used.

  When a surface light emitting element such as a VCSEL is used as the optical element 17, that is, in the optical module 1 on the transmission side, a driver IC that drives the surface light emitting element is used as the IC 18. When a surface light receiving element such as a PD is used as the optical element 17, that is, in the optical module 1 on the receiving side, an amplifier IC that amplifies an electric signal from the surface light receiving element is used as the IC 18. In the cable 100 with a module, the optical module 1 on the transmission side is provided at one end of the cable 10 and the optical module 1 on the reception side is provided at the other end, so that one-way communication from the transmission side to the reception side is performed.

  The optical element 17 is electrically connected to the electrical connector 13 via the flexible substrate 16 (electrical wiring of the film substrate 16a), the FPC connector 14, and the substrate 12 (electrical wiring of the substrate 12, electrode 12a).

  The optical element 17 is optically connected to the core of each optical fiber 15a of the ribbon fiber 15 via the 45 ° mirror 17a and the core 19a of the optical waveguide 19. The structure of the connection portion between the optical waveguide 19 and the ribbon fiber 15 will be described later.

  In the optical module 1, the cable 10 is extended from the cable 10 in the case 11 in order to cope with a change in the length of the ribbon fiber 15 extended from the end of the cable 10 by bending and stretching the cable 10. The extra length of the ribbon fiber 15 is accommodated by winding or bending the ribbon fiber 15.

  The ribbon fiber 15 is introduced into the case 11 so that the major axis direction thereof is perpendicular to the surface of the substrate 12, and is wound in the minor axis direction in the same plane parallel to the surface of the substrate 12. The extra length is accommodated in the case 11 by bending. In the present embodiment, the ribbon fiber 15 is bent in a substantially S shape when viewed from above, so that the extra length of the ribbon fiber 15 is accommodated in the case 11. You may make it go around.

  Although not shown in FIGS. 1 to 3, the cable 10 is an optical / electrical composite cable including a ribbon fiber 15 and an electric wire (not shown), and extends from the cable 10 into the case 11. The electric wire is electrically connected to the electric wiring on the back surface of the substrate 12 and is electrically connected to the electric connector 13 via the electric wiring of the substrate 12. The electric wire is used as, for example, a low-speed signal line or a power supply line.

  Now, in the optical module 1 according to the present embodiment, the flexible substrate 16 has a vertical portion 21 in which an end portion opposite to the FPC connector 14 is bent in a direction perpendicular to the surface of the substrate 12. The ribbon fiber 15 is connected to the vertical portion 21.

  The flexible substrate 16 has a parallel portion 22 extending in parallel to the surface of the substrate 12 between the FPC connector 14 and the vertical portion 21, and is formed in a substantially L shape. The optical element 17 and the IC 18 are provided on the surface of the parallel part 22 on the substrate 12 side, and are opposite to the FPC connector 14 of the parallel part 22 so that the optical element 17 and the IC 18 are separated from the substrate 12 (a space is formed). The side end is supported by a support member 20 made of glass. A heat radiating plate 24 for radiating heat generated in the optical element 17 and the IC 18 is provided on the surface of the flexible substrate 16 opposite to the substrate 12 of the parallel portion 22. The heat sink 24 is made of, for example, a copper plate.

  The optical waveguide 19 of the flexible substrate 16 is formed over the vertical portion 21 and the parallel portion 22, and the vertical portion 21 and the parallel portion 22 are connected by an arc portion 23 that is curved with a predetermined radius of curvature. That is, the flexible substrate 16 in the present embodiment includes the parallel portion 22, the arc portion 23, and the vertical portion 21 sequentially from the FPC connector 14 side.

  Since the optical waveguide 19 is also bent at the arc portion 23, the radius of curvature of the arc portion 23 is appropriately set so that the loss (light loss) at the arc portion 23 of the optical waveguide 19 does not become a problem. Good.

  As shown in FIG. 5, a groove 25 for fixing each optical fiber 15a of the ribbon fiber 15 is formed on the surface on the side where the optical waveguide 19 is formed in the vertical portion 21 of the flexible substrate 16, that is, the inner surface of the bending. ing.

  The groove 25 is perpendicular to the longitudinal direction (vertical direction in FIG. 5) of the flexible substrate 16 along the surface of the vertical portion 21 on which the optical waveguide 19 is formed, that is, the vertical portion. The ribbon fiber 15 is connected to the side of the vertical portion 21.

  The ribbon fiber 15 has the end covering 15b removed to expose the optical fiber 15a, and the exposed optical fiber 15a is disposed in the groove 25 and bonded and fixed with an adhesive (refractive index matching agent) or the like. Thus, the flexible substrate 16 is connected. In order to protect the exposed optical fiber 15a, a protective member may be provided so as to cover the optical fiber 15a and the groove 25.

  The core 19 a of the optical waveguide 19 in the vertical portion 21 extends linearly from the arc portion 23 side along the longitudinal direction of the flexible substrate 16, is bent 90 ° in an arc shape, and extends into the groove 25. It is optically connected to the core of the optical fiber 15a arranged.

  When the extra length is accommodated by bending the ribbon fiber 15 as in the present embodiment, the vertical portion 21 of the flexible substrate 16 is placed in the case 11 of the ribbon fiber 15 in order to increase the bending radius of the ribbon fiber 15 as much as possible. It is desirable to dispose it as far as possible from the introduction position. In the present embodiment, assuming that the vertical direction in FIG. 3 is the width direction, the ribbon fiber 15 is introduced from a position close to one end in the width direction (the upper side in FIG. 3), and the flexible substrate 16 is The flexible board 16 is arranged on the connector 13 side (position away from the cable 10) as much as possible, the longitudinal direction of the flexible board 16 is arranged along the width direction, and the vertical portion 21 is arranged on the other end in the width direction of the board 12 (see FIG. In FIG. 3, it is configured to be positioned on the lower side. As a result, the introduction position of the ribbon fiber 15 and the arrangement position of the vertical portion 21 become substantially diagonal positions in the case 11, so that the bending radius when the ribbon fiber 15 is bent by increasing the distance between the two is increased. In addition, it is possible to prevent problems such as breakage of the optical fiber 15a.

  When the ribbon fiber 15 is rotated once in the case 11, the vertical portion 21 may be arranged at any position, but in this case also, the vertical portion is set so that the bending radius of the ribbon fiber 15 is as large as possible. It is desirable to set 21 arrangement positions.

  The operation of the present embodiment will be described.

  In the optical module 1 according to the present embodiment, the end portion of the flexible substrate 16 opposite to the FPC connector 14 is bent in the direction perpendicular to the surface of the substrate 12 to form the vertical portion 21, and the vertical portion 21. The ribbon fiber 15 is connected to the cable.

  In order to fully accommodate the extra length of the ribbon fiber 15 in a limited space (substantially rectangular space) in the case 11, the major axis direction of the ribbon fiber 15 is perpendicular to the surface of the substrate 12. However, in the present invention, the ribbon fiber on the flexible substrate 16 is formed by bending the end portion of the flexible substrate 16 to form the vertical portion 21. A part of the surface including a portion to which the connector 15 is connected is parallel to the major axis direction of the ribbon fiber 15, whereby the ribbon fiber 15 can be connected to the flexible substrate 16 without twisting.

  That is, according to the present invention, it is possible to realize the optical module 1 in which the extra length of the ribbon fiber 15 is accommodated in the case 11 and can be connected to the flexible substrate 16 without twisting the ribbon fiber 15. As a result, unnecessary load is not applied to the ribbon fiber 15, and problems such as breakage of the optical fiber 15a can be prevented.

  Further, as in the background art (see FIG. 6), when the ribbon fiber 15 is twisted and connected to the flexible substrate 16, if the ribbon fiber 15 itself is twisted without applying a load, the ribbon fiber 15 accommodated in the case 11 is stored. In the present invention, since the ribbon fiber 15 can be connected to the flexible substrate 16 without twisting, the extra length of the ribbon fiber 15 accommodated in the case 11 is minimized. It becomes possible to limit.

  In the present embodiment, since the optical element 17 and the IC 18 are provided on the surface of the parallel portion 22 on the substrate 12 side, it is possible to provide the heat dissipation plate 24 on the surface of the parallel portion 22 opposite to the substrate 12. The heat generated in the optical element 17 and the IC 18 can be efficiently radiated.

  Further, in the present embodiment, the optical waveguide 19 is formed across the vertical portion 21 and the parallel portion 22, and the vertical portion 21 and the parallel portion 22 are connected by an arc portion 23 curved with a predetermined radius of curvature. Yes. When the vertical portion 21 and the parallel portion 22 are bent at right angles without rounding, the optical loss of the optical waveguide 19 increases at the bent portion, but the vertical portion 21 and the parallel portion 22 are connected to the arc portion 23. By connecting smoothly, the optical loss of the optical waveguide 19 at the bent portion can be suppressed.

  Although the case where the electrical connector 13 is an HDMI plug compliant with the HDMI standard has been described in the above embodiment, the present invention is not limited to this, and may be, for example, a USB (Universal Serial Bus) plug. In this case, the case 11 is formed in a size compliant with the USB standard, and the optical module-equipped cable 100 in which the optical module 1 is provided at both ends of the cable 1 is a so-called USB cable.

  In general, an HDMI cable or a USB cable having only a built-in electric wire deteriorates an electrical signal, so that long-distance signal transmission is difficult. However, according to the cable 100 with an optical module of the present invention, an optical cable is used. For example, signal transmission over a long distance of 30 to 100 m is possible.

  The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the spirit of the present invention.

  For example, although not mentioned in the above embodiment, when the flexible substrate 16 cannot be held in a bent state, such as when the vertical portion 21 is not self-supporting, a member that supports the vertical portion 21 may be separately provided. Good.

1 optical module 10 cable 11 case 12 substrate 13 electrical connector 14 FPC connector 15 ribbon fiber 16 flexible substrate 17 optical element 18 IC
19 Optical waveguide 20 Support member 21 Vertical part 22 Parallel part 23 Arc part 24 Heat sink

Claims (6)

An optical module provided at an end of a cable incorporating a plurality of optical fibers,
A case to which the cable is connected;
A substrate housed in the case;
A flexible substrate having an optical waveguide mounted on the substrate and optically connected to the core of the optical fiber; and
With
The plurality of optical fibers are ribbon fibers in which a plurality of the optical fibers are arranged in parallel, and are extended from the cable into the case so that the arrangement direction is perpendicular to the surface of the substrate .
In the case, the ribbon fiber extended from the cable is bent or bent in a direction perpendicular to the arrangement direction of the optical fibers in the same plane parallel to the surface of the substrate. The extra length of the ribbon fiber is accommodated,
The flexible substrate has a vertical portion bent in a direction perpendicular to the surface of the substrate,
In the vertical portion, the plurality of cores of the optical waveguide are formed to be bent in an arc shape in a direction parallel to the surface of the substrate and aligned in a direction perpendicular to the surface of the substrate,
An optical module configured to connect the end portion of the ribbon fiber to the vertical portion in a state in which the arrangement direction of the plurality of optical fibers is perpendicular to the surface of the substrate at the end portion of the ribbon fiber. An optical element mounted on the flexible substrate and optically connected to the core of the optical fiber via the optical waveguide;
The flexible substrate has a parallel portion extending parallel to the surface of the substrate,
The optical element is provided on a surface of the parallel portion on the substrate side,
Wherein the said substrate opposite to the surface of the parallel portion, claim 1 Symbol mounting the optical module of the heat radiating plate is provided. The optical waveguide is formed across the vertical part and the parallel part,
The optical module according to claim 2, wherein the vertical portion and the parallel portion are connected by an arc portion curved with a predetermined radius of curvature. The cable is a photoelectric composite cable that incorporates the plurality of optical fibers and electric wires,
Wherein said wire that extends into the casing from the cable, an optical module according to claim 1 to 3 which is electrically connected to the substrate. An HDMI plug compliant with the HDMI standard is provided on the substrate,
Wherein the case, the optical module according to any one of claims 1-4, which is formed to a size that conforms to the HDMI standard. The cable with an optical module which provided the optical module in any one of Claims 1-5 in the both ends of the cable which incorporated the some optical fiber.