JP2005085819A - Photoelectric composite board, optical waveguide, and optical waveguide with optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a fault to be easily repaired when the fault occurs in an photoelectric composite board composed of an optical waveguide mounted with optical elements and electronic circuit boards bonded thereto. <P>SOLUTION: A light emitting device 14 and a light receiving device 15 are mounted on the one side of the optical waveguide 10, and electronic circuit boards 30a and 30b are laminated on the other side of the optical waveguide 10. The light emitting device 14 and the electronic circuit board 30a are electrically connected together with via interconnect lines 22a, and the light receiving device 15 and the electronic circuit board 30b are electrically connected together with via interconnect lines 22b for the formation of the photoelectric composite board. A pair of connectors 20a and 20b which are used for electrically connecting the via interconnect lines 22a and 22b at the side of the optical waveguide 10 to the electric interconnect lines of the electronic circuit boards 30a and 30b are provided to the optical waveguide 10 and the electronic circuit boards 30a and 30b. As the result, the optical waveguide 10 and the electronic circuit boards 30a, 30b can be made detachable, these components are detached when a fault occurs, and the fault can be repaired. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optoelectric composite substrate in which an electronic circuit board and an optical waveguide for optical signal transmission are integrated by a connector, an optical waveguide suitable for manufacturing the optoelectric composite substrate, and an optical waveguide with an optical element.

  In optical communication systems including images that are becoming increasingly popular in the future, a dramatic increase in transmission capacity and a dramatic improvement in processing speed of information processing apparatuses are required. In such an environment, signal transmission over a relatively short distance, such as connections between wiring boards in electronic devices that are responsible for high-capacity high-speed communication, connections between semiconductor chips in a wiring board, or connections within a semiconductor chip With regard to the above, in place of the conventional signal transmission using a metal cable or metal wiring, optical transmission using an optical waveguide has come to be used.

As an important technique for supporting such optical transmission, there is a technique for connecting an optical waveguide to an optical element such as a vertical surface light emitting diode (VCSEL) or a photodiode (PD).
As a method of connecting an optical waveguide to an optical element, conventionally, a case in which a condensing lens is fitted on an electronic circuit board on which the optical element is mounted is covered, and a housing with a reflecting mirror is integrated with the case with a guide pin. A method for fixing the waveguide to the front surface of the reflection mirror has been proposed. (For example, refer nonpatent literature 1 etc.).

  However, in this method, since the case and the housing are fitted with the guide pins, the distance between the reflection mirror and the optical element is increased, and a condensing lens is required. In addition, since the lens is focused, the optical axis alignment between the optical element-lens-reflecting surface-optical waveguide is adjusted from the optical element so that the received light energy becomes maximum when the light receiving element is operated. It is necessary to use an active alignment method that adjusts the position of the component that reaches the optical waveguide. Further, when this active alignment operation is performed, static electricity may be generated between the components, and there is a problem that the optical element is easily deteriorated due to the static electricity.

  On the other hand, as a method for solving such a problem, a method of improving the connection accuracy between the optical element and the optical waveguide by directly mounting the optical element on the optical waveguide has been proposed (see, for example, Non-Patent Document 2).

  That is, in the proposed method, the end face of the optical waveguide is cut at an angle of 45 degrees with respect to the axial direction of the core to form a reflecting surface, and the laser light from the optical element is reflected by 90 degrees by the reflecting surface, The optical element is directly mounted on the optical waveguide so as to be incident on the core portion of the optical waveguide. Further, in this method, in order to supply power or an electric signal to the optical element, an optical waveguide on which the optical element is mounted is mounted on the electronic circuit board, and the electronic circuit board is connected via via wiring penetrating the optical waveguide. The electronic circuit board and the optical waveguide are integrated so as to supply power or an electric signal from the electrical wiring portion to the optical element mounted on the optical waveguide.

According to this method, a case or a housing for joining the optical waveguide and the optical element becomes unnecessary, the distance between the reflecting surface and the optical element becomes small, and a condensing lens becomes unnecessary. Also. Alignment is also possible with the passive alignment method, and the problem of deteriorating the optical element due to static electricity generated between the components during the active alignment operation is solved.
Electronics Packaging Society Journal Vol. 5 No. 5 AUG. 2002 Present state and future of optical circuit packaging technology (Ichiro Hiyama et al.) H15, sponsored by the Japan Advanced Technology Development Organization, 4th Electronic SI Research Report Meeting, Report Meeting Material 106 (Keiichi Kumai)

  By the way, in the above mounting method, in order to electrically connect the optical waveguide and the optical element or the optical waveguide and the electronic circuit board, a conductive thin film is formed on the end portion of the via wiring that penetrates the optical waveguide. It is necessary to connect the optical waveguide and the optical element or the optical waveguide and the electronic circuit board by solder reflow or flip chip bonding on the thin film.

  However, forming a thin film on an optical waveguide and bonding the optical waveguide and the optical element or the optical waveguide and the electronic circuit board by solder reflow or flop chip bonding or the like means that the optical waveguide and the optical element or the optical waveguide and the electronic circuit are joined. In some cases, adhesion to the substrate may not be obtained, and there is a problem that the joint surface is easily peeled off, and there is a risk of disconnection at the joint surface between the optical waveguide and the optical element or between the optical waveguide and the electronic circuit substrate.

  That is, during optical transmission through the optical waveguide, due to vibration, impact, mechanical bending force, heat, etc., the joint surface between the optical waveguide and the optical element or between the optical waveguide and the electronic circuit board may be peeled off or cracked. There is a possibility that the optical element cannot receive and emit light and light transmission cannot be performed due to disconnection at the joint surface.

  In this way, when optical transmission becomes impossible and repair of the defective part is necessary, the optical waveguide and the electronic circuit board are joined by a conductive thin film or a bump in the conventional method. It is necessary to disassemble the circuit board by heating or the like.

Therefore, in order to use the conventional method not only in industrial use but also in apparatuses widely used in offices and homes, there are significant problems from the viewpoint of maintainability, and a solution has been desired.
That is, it has been desired to reduce the time and cost required for repairing the defective portion that causes the optical transmission when the optical transmission becomes impossible.

  The present invention has been made in view of such a problem. The above-described optical element is mounted on an optical waveguide, the optical waveguide is stacked on an electronic circuit board, and the electronic circuit is connected via via wiring penetrating the optical waveguide. An object of the present invention is to make it possible to easily repair a defective portion when a defective portion occurs in an opto-electric composite substrate that transmits and receives electrical signals from the substrate.

The invention of the optoelectric composite substrate according to claim 1, which has been made to achieve the above object,
An optical element for transmitting and receiving optical signals;
An optical waveguide mounted with the optical element and having an optical path for transmitting an optical signal to be emitted from or incident on the optical element;
An electronic circuit board in which an electronic circuit for transmitting or receiving an electrical signal via the optical element is incorporated, and the optical waveguide is laminated via a surface opposite to the mounting surface of the optical element;
In order to electrically connect the electronic circuit board and the optical element, the optical waveguide is connected to the optical waveguide from a laminated surface on the electronic circuit board (in other words, a surface opposite to the mounting surface of the optical element). A plurality of via wirings provided so as to penetrate to the mounting surface of the element;
A photoelectric composite substrate comprising:
Provided to the optical waveguide and the electronic circuit board are a pair of connectors that electrically connect the respective via wirings on the optical waveguide side and the electric wirings on the electronic circuit board side and can be fitted to each other. It is characterized by that.

  In the photoelectric composite substrate configured as described above, since the optical waveguide and the electronic circuit board can be attached and detached through a pair of connectors, the conventional method is used when manufacturing the photoelectric composite substrate. Therefore, it is not necessary to directly join and integrate the optical waveguide carrying the optical element and the electronic circuit board by a bump or the like.

Therefore, the optical waveguide on which the optical element is mounted and the electronic circuit board can be manufactured by manufacturing processes most suitable for each, and the manufacturing process is simplified and the cost is reduced.
Furthermore, when a defect in the optical element or a defect such as peeling of the joint surface between the optical waveguide and the optical element occurs, it becomes impossible to transmit light and the defective part needs to be repaired. Since the waveguide and the electronic circuit board can be removed and repaired at the connector portion, it is not necessary to disassemble the heating portion of the joint between the optical waveguide and the electronic circuit board at the time of repair as in the conventional method. The repair becomes easy and the repair cost can be reduced.

  Note that the via wiring and the connection terminal of the connector need only be connected to the electrical wiring of the electronic circuit board, and may be configured by a single conductor. In particular, a signal having a high-frequency component such as a high-speed pulse signal is transmitted and received. In this case, the connector connection terminal and the via wiring may be coaxial. In other words, this makes it possible to transmit and receive a high-speed pulse signal and the like without being affected by noise or the like.

  In addition, when the optical waveguide and the electronic circuit board can be attached and detached as described above, the optical waveguide can be subjected to vibration, impact, mechanical bending, etc. It becomes easy to apply force. In this case, if the optical waveguide is made of an inorganic material such as glass, the optical waveguide becomes relatively hard, so that a force such as vibration or impact applied to the optical waveguide or mechanical bending is applied to the light. A stress is directly applied to the joint between the waveguide and the connector or the joint between the electronic circuit board and the connector, causing a problem that the joint is easily peeled off.

Therefore, in order to prevent such a problem, as described in claim 2, it is preferable to configure the photoelectric composite substrate with the optical waveguide having flexibility.
In other words, by making the optical waveguide have, for example, a polymer material-based flexibility, a force such as vibration, impact, or mechanical bending applied to the optical waveguide causes a joint between the optical waveguide and the connector or an electronic circuit. It is possible to alleviate the direct application of stress as a stress to the joint between the board and the connector, and to prevent the joint from peeling off.

  On the other hand, the invention according to claim 3 relates to an optical waveguide suitable for producing the optoelectric composite substrate according to claim 1, and can mount an optical element for transmitting and receiving an optical signal. A plurality of via wirings for inputting and outputting electrical signals to the mounted optical element are formed so as to penetrate from the mounting surface of the optical element to the back surface, and further, the via wiring is electrically connected to the back surface. The connector is attached so as to form

  Similarly, the invention according to claim 4 relates to an optical waveguide with an optical element suitable for producing the optoelectric composite substrate according to claim 1, and a plurality of optical elements for transmitting and receiving optical signals. An element is mounted, and a plurality of via wirings for inputting and outputting electrical signals to the mounted optical element are formed so as to penetrate from the mounting surface of the optical element to the back surface. The connector is attached so as to make an electrical connection.

  Therefore, if the optical waveguide according to claim 3 or the optical waveguide with an optical element according to claim 4 is used, an electronic circuit board on which a connector provided in the optical waveguide and a connector that can be fitted to each other are mounted. Are directly connected, and the photoelectric composite substrate of the present invention (Claims 1 and 2) can be easily realized.

  In addition, since the optical waveguide and the waveguide with an optical element have a connector, for example, it is connected to an external electronic circuit board via a harness or the like having a connector that can be fitted to the connector at one end. You can also

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view of an optoelectric composite substrate according to an embodiment to which the present invention is applied, cut along the optical axis of an optical waveguide.

  As shown in FIG. 1, the optoelectric composite substrate 1 of the present embodiment includes a light emitting element 14 such as a VCSEL, a light receiving element 15 such as a PD, an optical waveguide 10 mounting these optical elements, and an IC 31a. The electronic circuit board 30a and the electronic circuit board 30b on which the IC 31b is mounted.

Here, the optical waveguide 10 is long and is formed by covering a core 11 having a high refractive index serving as an optical path with a clad having a low refractive index.
A light emitting element 14 is mounted on one end of the optical waveguide 10 in the longitudinal direction, and a light receiving element 15 is mounted on the opposite end. The electronic circuit board 30a is connected to the surface opposite to the mounting surface of the light emitting element 14, and similarly, the electronic circuit board 30b is connected to the opposite surface of the light receiving element 15 mounting surface.

  The optical waveguide 10 includes a plurality of via wirings 22a penetrating from the mounting surface of the light emitting element 14 to the mounting surface of the electronic circuit board 30a (the via wiring in front of the cut surface is shown in FIG. 1 is provided, and the light emitting element 14 and the electronic circuit board 30a are electrically connected by the via wiring 22a.

  Similarly, the light receiving element 15 is also electrically connected to the electronic circuit board 30b by a plurality of via wirings 22b penetrating the optical waveguide 10 from the mounting surface of the light receiving element 15 to the mounting surface of the electronic circuit board 30b.

  In the optical waveguide 10, an optical path conversion unit 16 a is formed on the optical axis of the mounted light emitting element 14. As described in Non-Patent Document 2, the optical path changing unit 16a is formed by cutting the optical waveguide 10 by blade machining or the like at an angle of 45 degrees with respect to the optical axis direction of the core, and is perpendicular to the optical axis of the core. The laser beam incident from the direction is reflected and incident on the core, and the laser beam propagating through the core is reflected in the direction perpendicular to the optical axis of the core.

  Then, as described in Non-Patent Document 2, the light-emitting element 14 is aligned so that the optical axes of the light-emitting element 14 and the optical path changing unit 16a coincide with each other. Bonded by bonding or the like.

An IC 31a is mounted on the electronic circuit board 30a, and further, a power supply and other electronic circuits (not shown) necessary for operating the IC 31a are mounted.
Similarly, the light receiving element 15 is also adjusted in alignment so that the optical axis of the light receiving element 15 coincides with the optical path changing unit 16 b formed in the optical waveguide 10, and is joined to the optical waveguide 10.

An IC 31b is mounted on the electronic circuit board 30b, and further, a power source and other electronic circuits (not shown) necessary for operating the IC 31b are mounted.
On the electronic circuit board 30a side, a transmission signal from the IC 31a is input to the light emitting element 14 through the electrical wiring of the electronic circuit board 30a and the via wiring 22a. The light emitting element 14 performs electro-optical conversion on the input transmission signal and emits laser light. The emitted laser light is reflected by the optical path conversion unit 16a, enters the core 11 of the optical waveguide 10, and is transmitted to the electronic circuit board 30b side.

  On the electronic circuit board 30 b side, the transmitted laser light is reflected by the optical path conversion unit 16 b and is incident on the light receiving element 15. The light receiving element 15 photoelectrically converts the incident laser light and outputs a reception signal. The reception signal is input to the IC 31b through the electrical wiring of the electronic circuit board 30b through the via wiring 22b.

In this way, signals are input / output between the IC 31a and the IC 31b.
Here, the optical waveguide 10 and the electronic circuit board 30a, and the optical waveguide 10 and the electronic circuit board 30b are connected via a pair of connectors 20a and 20b, respectively. Hereinafter, the configuration of each of the connectors 20a and 20b will be described in detail by taking the connector 20a as an example.

FIG. 2 is an enlarged view of a mounting portion of the light emitting element 14 of FIG.
As shown in FIG. 2, the pair of connectors 20a for connecting the light emitting element 14 and the electronic circuit board 30a are composed of an adapter 40a and a socket 41a. The adapter 40 a is bonded to the surface of the optical waveguide 10 opposite to the surface on which the light emitting element 14 is mounted by the bumps 23. The pins of the adapter 40a are electrically connected to the via wiring 22a by the bumps 23.

  A socket 41a that fits with the adapter 40a is mounted on the surface of the electronic circuit board 30a. The plug of the socket 41a is electrically joined to the electric wiring (not shown) of the electronic circuit board 30a by the bumps 23.

  Here, the pin arrangement of the adapter 40a and the socket 41a is electrically associated (in other words, the electrical signal transmitted / received through the adapter 40a and the electrical signal transmitted / received through the socket 41a can be taken), Each is electrically connected to the via wiring 22a and the electric wiring of the electronic circuit board 30a.

Note that the pair of connectors 20b that connect the light receiving element 15 and the electronic circuit board 30b also includes an adapter and a socket, like the connector 20a.
In the photoelectric composite substrate 1 configured as described above, the electrical signal output from the IC 31a passes through the electrical wiring of the electronic circuit board 30a, passes through the socket 41a and the adapter 40a, and passes through the via wiring 22a to the light emitting element 14. Entered. Then, it is electro-optically converted by the light emitting element 14 and emitted as laser light, reflected by the optical path changing unit 16a, incident on the core 11, and transmitted.

  At the opposite end of the optical waveguide 10, the transmitted laser light is reflected by the optical path changing unit 16 b and is incident on the light receiving element 15. Then, the light receiving element 15 performs photoelectric conversion, and is output as an electrical signal, and is input to the IC 31b via the via wiring 22b, the adapter and socket constituting the connector 20b, and the electrical wiring of the electronic circuit board 30b. .

  Here, when this optical transmission is performed, for example, a defect in the light emitting element 14 or the light receiving element 15, a disconnection at the joint surface between the optical waveguide 10 and the light emitting element 14, or a light reception with the optical waveguide 10. If disconnection occurs at the joint surface of the element 15 and optical transmission becomes impossible, repair is required.

  At this time, in the conventional photoelectric composite substrate, the optical waveguide 10 and the electronic circuit board 30a, and the optical waveguide 10 and the electronic circuit board 30b are directly joined by bumps or the like. 10 and the electronic circuit board 30b must be disassembled by heating or the like, but according to the optoelectric composite board 1 of the present embodiment, the adapter 40a and the socket 41a constituting the pair of connectors 20a or the pair Since the electronic circuit board 30a and the optical waveguide 10 or the electronic circuit board 30b and the optical waveguide 10 can be separated through the adapter and the socket constituting the connector 20b, the repair can be performed very easily and the repair cost is reduced. can do.

  In addition, it is not necessary to manufacture the optical waveguide on which the light emitting element 14 and the light receiving element 15 are mounted, the electronic circuit board 30a, and the electronic circuit board 30b at the time of manufacturing, and therefore, the manufacturing process is most suitable for each. Thus, the manufacturing process can be facilitated, and the manufacturing cost can be reduced.

As mentioned above, although the Example of this invention was described, this invention is not limited to the said Example, A various aspect can be taken.
For example, in the above embodiment, the adapter 40a is mounted on the optical waveguide 10 side and the socket 41a is mounted on the electronic circuit board 30a side. However, the socket 41a is mounted on the optical waveguide 10 side and the electronic circuit board 30a side is mounted. You may make it mount | wear with the adapter 40a.

  In the above embodiment, the via wiring 22a, the pin of the adapter 40a, and the plug of the socket 41a have been described as one conductor, but they may be coaxial. As a result, particularly when a signal having a high frequency component such as a high-speed pulse signal is transmitted / received, a high-speed pulse signal or the like can be transmitted / received without being affected by noise or the like.

  Furthermore, in the above embodiment, the electronic circuit board 30a and the optical waveguide 10 are described as being directly joined by the pair of connectors 20a. However, the socket 41a that fits the adapter 40a on the optical waveguide 10 side is provided at one end. You may make it connect the optical circuit board 30a and the optical waveguide 10 using the harness etc. which have the adapter 40a fitted to the socket 41a by the side of the electronic circuit board 30a.

It is explanatory drawing showing the whole structure of the photoelectric composite board | substrate of an Example. It is the elements on larger scale of FIG. 1 showing the structure of the optical element mounting part of the photoelectric composite board | substrate of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Photoelectric composite board | substrate, 10 ... Optical waveguide, 11 ... Core, 12 ... Cladding, 14 ... Light emitting element, 15 ... Light receiving element, 16a, 16b ... Optical path conversion Part, 20a, 20b ... connector, 22a, 22b ... via wiring, 23 ... bump, 30a, 30b ... electronic circuit board, 31a, 31b ... IC, 40a, 40b ... adapter , 41a, 41b... Sockets.

Claims (4)

An optical element for transmitting and receiving optical signals;
An optical waveguide mounted with the optical element and having an optical path for transmitting an optical signal to be emitted from or incident on the optical element;
An electronic circuit board in which an electronic circuit for transmitting or receiving an electrical signal via the optical element is incorporated, and the optical waveguide is laminated via a surface opposite to the mounting surface of the optical element;
In order to electrically connect the electronic circuit board and the optical element, a plurality of vias provided in the optical waveguide so as to penetrate from the laminated surface to the electronic circuit board to the mounting surface of the optical element Wiring and
A photoelectric composite substrate comprising:
Provided to the optical waveguide and the electronic circuit board are a pair of connectors that electrically connect the respective via wirings on the optical waveguide side and the electric wirings on the electronic circuit board side and can be fitted to each other. A photoelectric composite substrate characterized by the above.   The photoelectric composite substrate according to claim 1, wherein the optical waveguide has flexibility. An optical waveguide capable of mounting an optical element for transmitting and receiving an optical signal, and having an optical path for transmitting an optical signal to be emitted from the mounted optical element or incident on the optical element,
Forming a plurality of via wirings for inputting and outputting electrical signals to the optical element so as to penetrate from the mounting surface of the optical element to the back surface;
An optical waveguide, wherein a connector for detachably connecting each via wiring to an external electronic circuit is provided on a surface opposite to the mounting surface of the optical element. An optical element with an optical element on which an optical element for transmitting and receiving an optical signal is mounted and having an optical path for transmitting an optical signal to be emitted from the optical element or incident on the optical element,
Forming a plurality of via wirings for inputting and outputting electrical signals to the optical element so as to penetrate from the mounting surface of the optical element to the back surface;
An optical waveguide with an optical element, wherein a connector for detachably connecting the via wiring to an external electronic circuit is provided on a surface opposite to the mounting surface of the optical element.

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