JP2010145823A - Photoelectric transducer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photoelectric transducer miniaturizing an optical element and in which attenuation of communication light is prevented. <P>SOLUTION: The optical element 2 has a light emitting part 22 or a light receiving part 21 on the upper face, and has an electrode 23 on the lower face. In a ferrule end face 42, a plurality of guide pin engaging holes 41 are opened for inserting and engaging a guide pin, and an optical transmission path end face 51 of an optical fiber 5 is exposed. On a circuit substrate 7 in which an electronic circuit is formed, an adaptor 3 in which a plurality of guide pin inserting holes 31 are open on the upper face is provided. On the upper face 33 of the adaptor 3, an optical element 2 in which an electrode 23 is mounted in flip-tip on the electric wiring inside an electronic circuit, is arranged with the light receiving part 21 or the light emitting part 22 facing upward. The ferrule 4 and the adaptor 3 are engaged by inserting a common guide pin into the guide pin engaging hole 41. As a result, the ferrule 4 and the adaptor 3 are coupled to each other so that the optical transmission path end face 51 and the light receiving part 21 or the light emitting part 22 on the upper face of the optical element 2 are faced with each other so as to perform an optical communication. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a photoelectric conversion device that performs conversion between an optical signal and an electrical signal.

  In recent years, many electronic circuits are used in electrical equipment. An electric device using an electronic circuit includes information processing means for transmitting and receiving information by electricity, and can perform a complicated operation. Electrical devices are required to be smaller and to operate faster. Accordingly, the degree of integration of electronic circuits provided in electrical devices is increased, and more electrical wiring is provided in a small area, or the frequency used for electronic circuits. It is demanded to raise.

  However, when the integration degree of electronic circuits is increased, electromagnetic waves emitted from individual electric wirings affect other electric wirings, or high frequency band noises are generated by increasing the frequency used for electronic circuits, A problem arises in that high-precision matching of characteristic impedance is required to prevent reflection loss, resulting in high costs.

  For this reason, researches have been conducted on electrical equipment using optical communication that performs transmission / reception of information necessary for operation of electrical equipment not by electricity but by light as the operation speed and size of the electrical equipment increase. Already, in Internet communication, replacement from electrical communication to optical communication is progressing, such as changing from conventional ADSL communication using a metal telephone line to optical communication. Similarly, an electronic circuit provided in an electrical device Attempts have been made to perform communication between circuit boards provided with a signal, and communication in an electronic circuit using a signal by light. Communication using communication light that propagates information has the advantages of being unaffected by electromagnetic waves, having low transmission loss, and having a wide transmission band, and is considered a promising technology.

  The technology to communicate between electronic circuits by optical communication and to transmit information in the electronic circuit is at the stage of research, and has reached the point where all information transmission is performed from electrical signals to optical signals. Optical communication is partially used in electronic circuits. Therefore, a means for converting between telecommunications and optical communications is required. Therefore, in an electrical device that uses both electrical communication and optical communication, a light receiving unit such as a photodiode that converts an optical signal into an electrical signal, an LD (Laser Diode) that converts an electrical signal into an optical signal, or a VCSEL (Vertical Cavity Surface). A photoelectric conversion device that includes a light emitting unit such as an emitting laser (LED) or a light emitting diode (LED) and performs conversion between an electric signal and an optical signal is used.

  For example, in the photoelectric conversion device 101 disclosed in Japanese Patent No. 3729240, a ferrule 131 is provided at the end of the optical fiber 121 as shown in FIG. A conductive layer 132 is provided on the surface of the ferrule 131, and an optical element 111 is provided on the conductive layer 132 through an electrode 115 and a dummy electrode 116. The optical element 111 and the conductive layer 132 are electrically connected to the electrode 115 through a wire 114 connected to another electrode 113.

The optical element 111 is provided with a light receiving portion 112 so as to face the cross section of the optical transmission line on the end surface 122 of the optical fiber 121. A light emitting unit may be provided instead of the light receiving unit 112. The light receiving unit 112 converts the optical signal received from the optical fiber 121 into an electrical signal. The end face 122 of the optical fiber 121 and the optical element 111 must be accurately aligned. If the position is shifted, the communication light emitted from the optical fiber 121 to the light receiving unit 112 or the communication light emitted from the light emitting unit to the optical fiber 121 when the light receiving unit 112 is provided instead of the light receiving unit 112 is weakened. As a result, communication light is attenuated. If the optical element 111 is provided separately from the ferrule 131, it is difficult to align the optical fiber 121 and the optical element 111 with high accuracy, so the optical element 111 must be provided integrally with the ferrule 131. At this time, the light receiving portion 112 (or the light emitting portion) is provided between the electrode 115 and the dummy electrode 116.
Japanese Patent No. 3729240

  However, in this case, since the optical element 111 must be provided so as to straddle the end face 122 of the optical fiber 121, the optical element 111 must be larger than the diameter of the optical fiber 121, and the optical element 111 is small. There has been a problem that cost reduction due to downsizing of the optical element 111 cannot be realized.

  The present invention has been invented in view of the above-described background art, and an object thereof is to provide a photoelectric conversion device that can reduce the size of an optical element and prevent attenuation of communication light.

  In order to solve the above problems, the invention of claim 1 of the present application includes a ferrule through which an optical fiber is inserted, and an adapter provided on a circuit board connected to the ferrule and formed with an electronic circuit, A light receiving unit or an electric signal that is provided on the end face of the optical transmission line of the optical fiber provided on the ferrule and on the coupling surface that is coupled to the ferrule of the adapter and is electrically connected to an electronic circuit to convert the optical signal into an electric signal. A photoelectric conversion device arranged so as to be opposed to an optical element having a light emitting portion for converting into an optical signal so as to be optically coupled so that optical communication is possible, and a guide pin is inserted and locked to the end face of the ferrule A plurality of guide pin locking holes for opening the optical fiber and the end face of the optical fiber are exposed, and a plurality of guide pin insertion holes for inserting the guide pins are opened on the coupling surface of the adapter. By inserting and locking the guide pins into the guide pin locking holes of the rule and the guide pin insertion holes of the adapter, the ferrule and the adapter are coupled, and the optical element has a light emitting portion or a light receiving portion on the surface facing the ferrule. The electrode has an electrode on the opposite surface, and the electrode is disposed on the coupling surface of the adapter in a state of being flip-chip mounted on the electric wiring in the electronic circuit.

  In the photoelectric conversion device according to claim 1, by providing all the electrodes on the lower surface of the optical element, it is possible to eliminate the space for wire bonding in the case where the electrodes are provided on the upper surface as in the prior art. Can be realized.

  In addition, since the upper surface of the optical element is only the light receiving part or the light emitting part, the distance between the optical fiber end face and the light receiving part or the light emitting part can be reduced. For example, a multi-core optical fiber and a plurality of optical elements are arranged to face each other. Such optical interference between channels in the case of multi-channel optical transmission can be further prevented.

  Furthermore, since the optical element is flip-chip mounted on the electrical wiring in the electronic circuit, the optical element can be mounted with less error, and the optical axis between the optical fiber end surface and the light receiving unit or light emitting unit on the upper surface of the optical element. The alignment accuracy can be increased and the attenuation of communication light can be prevented.

  1-3 have shown the photoelectric conversion apparatus which is embodiment of this invention. In addition, the upper surface, the lower surface, and the lower surface in all the embodiments described below refer to the vertical direction in FIG. As shown in FIGS. 1 to 3, the photoelectric conversion device includes a light receiving unit 21 that converts an optical signal into an electrical signal, a light emitting unit 22 that converts an electrical signal into an optical signal, and a light receiving unit 21 or a light emitting unit 22 that is electrically connected. And an optical element 2 having an electrode 23 for inputting / outputting an electric signal, and the light receiving portion 21 or the light emitting portion 22 corresponds to the end face of the optical fiber 5 exposed at the end face 42 of the ferrule 4. By installing the optical element 2 so as to face the road end face 51, conversion between an optical signal transmitted by the optical fiber 5 and an electric signal is performed.

  The optical element 2 has a light receiving portion 21 or a light emitting portion 22 on its upper surface (a surface facing the end surface 42 of the ferrule 4 in FIG. 1) and an electrode 23 on its lower surface (a surface facing the circuit board 7 in FIG. 1). The ferrule 4 is an MT ferrule 4a for a multi-core optical fiber. A plurality of guide pin locking holes 41 for inserting and locking the guide pins 6 are opened on the ferrule end face 42 of the MT ferrule 4a. The end face 51 of the optical transmission path, which is the end face of the optical transmission path received in plurality, is exposed.

  On the circuit board 7 on which the electronic circuit is formed, the adapter 3 having a plurality of guide pin insertion holes 31 opened on the upper surface is provided. The optical element 2 is provided on the upper surface 33 of the adapter 3 and the electrode 23 is connected to the electric wiring in the electronic circuit. Are arranged in a flip-chip mounted state.

  The MT ferrule 4a and the adapter 3 insert and lock the common guide pin 6 shown in FIG. 3 into the guide pin locking hole 41 of the MT ferrule 4a and the guide pin insertion hole 31 of the adapter 3, thereby transmitting light. The road end surface 51 and the light receiving unit 21 or the light emitting unit 22 on the upper surface of the optical element 2 are coupled so as to face each other so that optical communication is possible.

  Hereinafter, the photoelectric conversion device of this embodiment will be described in more detail. As shown in FIG. 1, two photoelectric conversion devices 1 are provided on the upper surface of the circuit board 7. An adapter 3 is provided on the upper surface of the circuit board 7. The adapter 3 is provided with a recess 32 on the upper surface, and the optical element 2 is disposed in the recess 32.

  A conductor electrically connected to the electric wiring of the electronic circuit formed on the circuit board 7 is exposed at the bottom of the recess 32, and the electrode 23 provided on the lower surface of the optical element 2 is connected to the conductor. Electrically connected.

  This conductor is a sheet metal lead frame formed integrally with the adapter 3. This conductor may be formed on the surface of the adapter 3 by so-called MID (Modified Interconnect Device) that three-dimensionally forms a wiring pattern on a resin molded product. Alternatively, the bottom of the recess 32 may be on the circuit board 7, and the optical element 2 may be directly connected to the wiring of the electronic circuit formed on the circuit board 7.

  A light receiving unit 21 is provided on the upper surface of the optical element 2 included in the photoelectric conversion device 1 on the left side in FIG. 1, receives an optical signal transmitted by the optical fiber 5, converts it into an electrical signal, and transmits it to an electronic circuit. A light emitting unit 22 is provided on the upper surface of the optical element 2 included in the photoelectric conversion device 1 on the right side in FIG. 1, and converts an electrical signal in the electronic circuit into an optical signal and transmits it to the optical fiber 5.

  A plurality of guide pin insertion holes 31 are formed in the upper surface of the adapter 3, and one end of the guide pin 6 is inserted. The other ends of the plurality of guide pins are inserted and locked in guide pin insertion holes 41 formed in the ferrule end face 42.

  FIG. 2 shows an optical element 2 provided in the photoelectric conversion device 1. As shown in FIG. 2A, only the light receiving unit 21 or the light emitting unit 22 is provided on the upper surface. By not providing an electrode on the upper surface, wire connection is eliminated in the optical element 2 and the optical transmission path end face 51 and the upper surface of the optical element 2 can be approached to prevent attenuation of communication light. As shown in FIG. 2B, the lower surface is provided with electrodes 23 for flip chip mounting, and the electrodes 23 on the lower surface are electrically connected to a conductor via bumps 24 in the flip chip mounting.

  FIGS. 3A and 3B are views from the top of the photoelectric conversion device 1 of FIG. The state provided on the circuit board 7 is shown. The recess 32 is provided between the two guide pin locking holes 31 opened in the upper surface 33 of the adapter 3. On the circuit board 7, an IC 8 for driving the light receiving part or the light emitting part is provided.

  4A and 4B are modifications of FIG. In FIG. 3, the MT ferrule 4 a and the adapter 3 are disposed so that the optical fiber 5 is disposed substantially perpendicular to the surface of the circuit board 7. On the other hand, the MT ferrule 4a and the adapter 3 are disposed so that the optical fibers 5 are disposed substantially in parallel. Similarly to FIG. 3, an IC 8 is disposed on the circuit board 7. By arranging as shown in FIG. 4, it is possible to further reduce the size and height.

  Therefore, in the photoelectric conversion device 1 of this embodiment, the cost can be reduced by downsizing as compared with the optical element 2 having the light receiving unit 21 or the light emitting unit 22 and the electrode 23 on the same surface as in the past. became. Further, since the optical element 2 is flip-chip mounted on the electrical wiring in the electronic circuit, the optical element 2 can be mounted with less error, and the optical transmission path end face 51 and the light receiving portion 21 on the upper face of the optical element 2 or The optical axis alignment accuracy with the light emitting unit 22 is increased, and attenuation of communication light can be prevented.

Further, by disposing the plurality of optical elements 2 in the recess 32, the optical fiber 5 termination surface 51 exposed on the end face 42 of the MT ferrule 4a coupled to the adapter 3 and the optical element 2 upper surface The multi-core optical fiber 5a having the MT ferrule 4a at the end and the optical communication using a plurality of optical transmission lines for separate communication simultaneously are possible. It can also be. At this time, since the termination surface 51 of the multi-core optical fiber 5a is provided with a number of optical transmission line termination surfaces of a large number of optical fibers 5 in a narrow range, the gap between the optical transmission path termination surface and the light receiving unit 21 or the light emitting unit 22 If the distance is long, the communication light emitted from the light emitting unit 22 is irradiated to the end surfaces of the plurality of optical transmission paths due to the diffusion of the communication light, or the communication light from the end surfaces of the optical transmission paths is received by the plurality of light receiving units 21. May cause interference of communication light. Therefore, the distance between the optical element 2 and the end face 51 of the optical fiber 5 needs to be as short as possible. However, since the plurality of optical elements 2 are flip-chip mounted, there is little error in the installation position, and the multi-core optical fiber 5a. Even if the distance between the end surface 51 of the optical element 2 and the optical element 2 is reduced, the optical element 2 can be arranged so that the light receiving unit 21 or the light emitting unit 22 provided on the upper surface and the optical transmission line end surface face each other. It is possible to further prevent communication interference due to spreading of data.

  FIG. 5 shows an embodiment in which each of the plurality of optical transmission path end faces 51 in the multi-core optical fiber 5a and the plurality of optical elements 2 arranged in the recess 32 are arranged to face each other. FIG. 5A is a diagram showing conventional multi-channel optical transmission, and FIG. 5B is a diagram showing multi-channel optical transmission according to the present invention. As shown in FIG. 5A, in the conventional case, if the distance between the optical fiber end surface 51 of the optical fiber 5 and the light receiving unit or the light emitting unit provided on the upper surface of the optical element 2 is long, the light emitting unit 22 is diffused by the diffusion of communication light. The communication light emitted from the optical transmission path end face 51 is irradiated on the plurality of optical transmission path end faces 51, or the communication light from the optical transmission path end face 51 is irradiated on the plurality of light receiving sections 21, thereby causing interference of the communication light. May occur. However, in FIG. 5B, which is the present invention, the optical fiber end face 51 and the light receiving part or light emitting part provided on the upper surface of the optical element 2 can be brought closer than in the conventional case. Generation of X can be prevented.

  In the present embodiment, the ferrule 4 is the MT ferrule 4a for multi-core optical fiber. However, the ferrule 4 of the present invention is not limited to this, and it can be applied even if a single-core optical fiber is used. .

1 is a front view showing a part of a photoelectric conversion device according to the present invention. The photoelectric conversion apparatus of this invention is shown, (a) is a perspective view seen from the upper surface, (b) is a perspective view shown from the lower surface. BRIEF DESCRIPTION OF THE DRAWINGS (a) which shows the optical converter in embodiment of this invention is a top view, (b) is a perspective view which shows the optical fiber couple | bonded with an adapter. (A) which shows the optical converter in another embodiment of this invention is a top view, (b) is a perspective view which shows the optical fiber couple | bonded with an adapter. The front view which shows typically the effect of the photoelectric conversion apparatus of this invention. Sectional drawing which shows the photoelectric conversion apparatus of a prior art example from the front.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoelectric conversion apparatus 2 Optical element 21 Light-receiving part 22 Light-emitting part 23 Electrode 24 Bump 3 Adapter 31 Guide pin insertion hole 32 Recessed part 4 Ferrule 4a MT ferrule 41 Guide pin locking hole 42 Ferrule end surface 5 Optical fiber 5a Multi-core optical fiber 51 Light Transmission path end face 6 Guide pin 7 Circuit board 8 IC

Claims (1)

A ferrule through which an optical fiber is inserted, and an adapter provided on a circuit board connected to the ferrule to form an electronic circuit, an end face of an optical transmission line of the optical fiber provided in the ferrule, and the adapter An optical element having a light receiving portion that is provided on a coupling surface to be coupled to the ferrule and is electrically connected to the electronic circuit to convert an optical signal into an electrical signal or a light emitting portion that converts an electrical signal into an optical signal. A photoelectric conversion device disposed so as to be optically coupled so as to be capable of optical communication,
A plurality of guide pin locking holes for inserting and locking the guide pins are opened on the end surface of the ferrule, and the end surface of the optical fiber is exposed, and a guide pin is provided on the coupling surface of the adapter. A plurality of guide pin insertion holes to be inserted are opened, and the ferrule and the adapter are coupled by inserting and locking the guide pin to the guide pin locking hole of the ferrule and the guide pin insertion hole of the adapter,
The optical element has a light emitting portion or a light receiving portion on the surface facing the ferrule and an electrode on the opposite surface, and the electrode is arranged in a state where the electrode is flip-chip mounted on the electric wiring in the electronic circuit. A photoelectric conversion device characterized by being provided.

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