JP4850147B2 - Optical module - Google Patents

Description

  The present invention relates to an optical module.

  In the field of optical communication using light as an information transmission medium, an optical module including an optical element that mutually converts an optical signal and an electrical signal is used to receive or transmit an optical signal transmitted through an optical fiber or the like. ing. A surface emitting element typified by a vertical cavity surface-emitting laser (VCSEL) is used for the conversion from an electrical signal to an optical signal, and a PIN is used for the conversion from an optical signal to an electrical signal. A surface light receiving element typified by a photodiode is used. These optical elements are electrically connected to the substrate, and optical fibers and the like are optically connected to the optical elements.

  Such an optical module has an optical transmission body such as an optical fiber from the viewpoint of workability when optical wiring such as an optical fiber is performed on a wiring board (printed wiring board or board), and ease of maintenance and replacement. It is desirable to be detachable via a connector.

  In addition, when an optical fiber or the like is attached to or detached from the optical element, a structure for attaching or detaching the optical fiber or the like around the component on which the optical element is mounted should be provided if it is configured to be attached to and detached from the wiring board in the horizontal direction. Since it cannot be obtained, there is a problem that other parts cannot be mounted in the space, and the mounting density cannot be increased. Therefore, it is desirable that attachment / detachment of an optical fiber or the like can be performed in a direction perpendicular to the wiring board.

Conventionally, in order to meet such demands, an optical element is mounted so that its light emitting / receiving surface is horizontal with respect to the wiring board, and a reflection mirror is provided on the end face of an optical fiber or the like to vertically align the optical axis. There has been proposed an optical module that optically connects an optical fiber or the like and an optical element so as to be detachable in a vertical direction by using a connector converted into (see Patent Document 1).
JP 2006-65358 A

  However, in the optical module that optically connects the optical fiber or the like and the optical element as described above in a detachable manner in the vertical direction, the upper structure that is a connector such as an optical fiber is attached to various electronic components including the optical element. There is a problem that the work of optically aligning and mounting an optical fiber or the like to an optical element mounted on the substrate is complicated.

  In addition, when optical fibers are optically aligned with optical elements mounted on a substrate, the vertical distance between the optical fibers and the optical elements is restricted by other electronic components mounted around the optical elements. Therefore, for vertical alignment, a lens is disposed between the optical fiber and the optical element for optical connection. When a lens is used, the height of the optical fiber or the like and the optical element is adjusted each time the lens is attached or detached, and a complicated operation may be required for optical connection. Further, when a lens is used, there is a problem that the cost of the optical module increases.

  The present invention has been made in view of the circumstances as described above, a lens for optical connection can be omitted, an optical module can be manufactured at low cost, and optical connection can be easily performed. It is an object to provide an optical module that can be attached and detached.

  The present invention is characterized by the following in order to solve the above problems.

First, an optical module of the present invention is an optical module that optically connects an optical fiber that transmits an optical signal and an optical element that converts the optical signal into an electrical signal or converts the electrical signal into an optical signal. And
The optical axis is bent so that the optical axis on the outer side and the optical axis on the optical element side are substantially perpendicular to each other and the end face of the optical fiber is flush with the bottom surface of the upper structure. An upper structure having a holding member for holding the fiber ;
An electronic device in which a plurality of electronic components including an optical element are mounted, and the upper structure is positioned on the upper side so that the optical fiber of the upper structure is optically connected to the optical element, and is detachably disposed. and the component mounting board, equipped with a,
In the electronic component mounting board, the electronic component is mounted in a single cavity bounded by a wall which is erected on the substrate,
The concave portion constituting the single cavity surrounded by the wall portion erected on the electronic component mounting substrate has a step surface (36) having a first depth from the upper surface of the wall portion, and the step surface. An adjacent surface (81) that is adjacent and positioned deeper than the step surface,
The optical element (40) has a first thickness and is disposed on the step surface.
The other electronic component (80) is thicker than the optical element and is disposed on the adjacent surface .

Second, an optical module of the present invention is an optical module that optically connects an optical fiber that transmits an optical signal and an optical element that converts the optical signal into an electrical signal or converts the electrical signal into an optical signal. And
The optical axis is bent so that the optical axis on the outer side and the optical axis on the optical element side are substantially perpendicular to each other and the end face of the optical fiber is flush with the bottom surface of the upper structure. An upper structure having a holding member for holding the fiber ;
An electronic device in which a plurality of electronic components including an optical element are mounted, and the upper structure is positioned on the upper side so that the optical fiber of the upper structure is optically connected to the optical element, and is detachably disposed. and the component mounting board, equipped with a,
In the electronic component mounting board, the electronic component is mounted in a single cavity bounded by a wall which is erected on the substrate,
The concave portion constituting the single cavity surrounded by the wall portion erected on the electronic component mounting substrate has a step surface (36) having a first depth from the upper surface of the wall portion, and the step surface. An adjacent surface (81) located adjacent and shallower than the step surface,
The optical element (40) has a first thickness and is disposed on the step surface.
The other electronic component (80) is thinner than the optical element and is disposed on the adjacent surface .

Third, in the first or second optical module, in the single cavity,
The upper surface of the optical element and the upper surface of the other electronic component are arranged so as to be substantially in the same plane .

  According to the first aspect of the present invention, the electronic component mounting substrate is formed in a cavity shape, the optical element is mounted on the step surface, and the upper structure is brought into contact with the upper surface of the wall portion of the electronic component mounting substrate for optical connection. Therefore, the vertical distance between the optical transmission body of the upper structure and the optical element on the electronic component mounting substrate can be defined by the upper surface of the wall portion and the step surface of the electronic component mounting substrate.

  In other words, the optical element is not limited by the thickness of other electronic components, but according to the optical conditions for optical connection between the end face of the optical transmission body of the upper structure and the optical element of the electronic component mounting substrate. It is possible to appropriately set the cavity depth of the step surface on which is mounted.

  Further, with such a configuration, a lens for optical connection can be omitted, and as a result, an optical module can be manufactured at low cost.

  Furthermore, since the upper structure is brought into contact with the upper surface of the wall portion of the electronic component mounting board, the height for optical connection can be easily adjusted, so that the mounting operation for optical connection is easy.

  According to the second aspect of the invention, the optical element is mounted on the stepped surface raised to the adjacent surface on which the other electronic component is mounted according to the relative thickness of the optical element and the other electronic component. Therefore, in addition to the effect of the first invention, the thickness of the other electronic component regulates the vertical distance between the optical transmission body of the upper structure and the optical element on the electronic component mounting board. Therefore, the lens for optical connection can be omitted, and as a result, the optical module can be manufactured at low cost.

  According to the third aspect of the invention, the optical element is placed on the stepped surface that is lowered with respect to the adjacent surface on which the other electronic component is mounted according to the relative thickness of the optical element and the other electronic component. In addition to the effect of the first invention, the vertical distance between the optical transmission body of the upper structure and the optical element on the electronic component mounting board is regulated by the thickness of the other electronic component. Therefore, the lens for optical connection can be omitted, and as a result, the optical module can be manufactured at low cost.

  In this specification, the “optical transmission body” includes an optical fiber made of glass or resin, an optical waveguide made of resin, or the like. In the following embodiment, an example using an optical fiber will be described. However, the optical transmission body applied in the present invention is not limited to this, and various types of optical transmission lines such as an optical waveguide can be configured. Things can be applied.

  In the present specification, the “optical element” includes not only one having a single light receiving / emitting surface but also one having a plurality of light receiving / emitting surfaces arranged in an array or the like. Specific examples of the optical element include a surface light emitting element such as a VCSEL and a surface light receiving element such as a PIN photodiode. The surface light emitting elements and / or the light receiving and emitting surfaces of the surface light receiving elements are arranged in an array. It may be integral.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 are perspective views showing an optical module according to an embodiment of the present invention. FIG. 1 shows a state in which the optical connection and the electrical connection are disconnected, and FIG. 2 shows a state in which the optical connection and the electrical connection are made. Yes.

  As shown in FIG. 1, the optical module 1 of this embodiment includes an upper structure 5 in which an optical fiber 7 is held by a holding member 6, an electronic component mounting board 30 on which an optical element 40 is mounted, and anisotropic conductivity. A sheet 60 and a fitting member 50 fixed on a wiring board 70 (printed wiring board or board) are provided.

  In this optical module 1, an anisotropic conductive sheet 60 is disposed in an opening 51 in a fitting member 50 on a wiring substrate 70, an electronic component mounting substrate 30 is disposed thereon, and an upper structure is formed thereon. 2 is fitted vertically as shown in FIG. 2, and the optical fiber 7 of the upper structure 5 and the optical element 40 of the electronic component mounting substrate 30 are optically connected, and the electronic component mounting substrate 30 and the wiring are connected. The substrate 70 is electrically connected via the anisotropic conductive sheet 60. The mounted optical module 1 shown in FIG. 2 constitutes a compact module having a width of 10 mm × 10 mm and a thickness of 6.4 mm, for example.

  As shown in FIGS. 3A and 3B, the upper structure 5 includes a plurality of (in this embodiment, 12) optical fibers 7 arranged in parallel from the back surface of the resin holding member 6. The tape fiber 8 enters the holding member 6 horizontally, the optical fiber 7 is bent in an arc shape in the holding member 6, and the end face 7 a of the optical fiber 7 is vertically exposed from the lower surface of the holding member 6. Yes.

  A pair of shoulder portions 12 forming a tapered surface along the peripheral edge portion are provided on both peripheral edge portions parallel to the optical fiber 7 on the upper surface of the holding member 6, and are fitted into the fitting member 50 of FIG. 1. The pair of protrusions 52 provided on the upper portion of the fitting member 50 abuts against the shoulder 12 of the holding member 6 and presses downward.

  Further, as shown in FIG. 1, the holding member 6 is provided with two positioning holes 11, which are erected on the optical element mounting substrate 30 when fitted into the fitting member 50 of FIG. The positioning pins 42 thus inserted are inserted into the positioning holes 11 of the holding member 6 so that the upper structure 5 and the electronic component mounting board 30 are positioned in the horizontal direction.

  The holding member 6 includes an upper member 10 and a lower member 20 as shown in FIGS. 3A and 3B, and the optical fiber 7 is sandwiched between the upper member 10 and the lower member 20. It comes to hold. On the lower surface side of the upper member 10, guide grooves having a V-shaped cross section, for example, are provided in parallel on a curved surface corresponding to the arc shape of the optical fiber 7, and the optical fiber 7 is 1 in each of these guide grooves. Each book is arranged and guided. On the other hand, an optical fiber holding surface having a curved surface corresponding to the arc shape of the optical fiber 7 is provided on the upper surface side of the lower member 20, and by sandwiching the optical fiber 7 between the upper member 10 and the lower member 20, The optical fiber 7 is held in a state bent in an arc shape between the guide groove of the upper member 10 and the optical fiber holding surface of the lower member 20.

  4 is a top perspective view of the electronic component mounting board 30, and FIG. 5 is a cross-sectional view. As shown in FIG. 4, the electronic component mounting substrate 30 includes a box-shaped ceramic substrate 31 in which a wall portion 32 is erected along the outer peripheral portion, and a light is placed at a front position on the ceramic substrate 31. An optical element 40 in which the same number of light receiving and emitting surfaces as the fiber 7 are arranged is mounted. The optical element 40 includes a VCSEL as a surface light emitting element and a PIN photodiode as a surface light receiving element. The upper surface 32a of the wall portion 32 forms an optical reference surface, and the end surface 7a of the optical fiber 7 and the optical element 40 are positioned in the vertical direction by contacting the lower surface of the upper structure 5.

  A driver integrated circuit device 41 of the optical element 40 is mounted behind the optical element 40 on the ceramic substrate 31, and the optical element 40 and the driver integrated circuit device 41 are connected by a bonding wire. In addition, other electronic components are mounted on the ceramic substrate 31, and the electronic components on the ceramic substrate 31 pass through through holes that penetrate the ceramic substrate 31 directly below the electronic components or via the printed wiring 33. , Electrically connected to a back electrode disposed on the back surface of the ceramic substrate 31 and having a pitch of 500 μm, a diameter of 300 to 350 μm, and a height of 10 μm, for example.

  A pair of positioning pins 42 having a protruding height of 2 mm and a protruding portion diameter of 0.7 mm are erected at positions on both sides of the optical element 40 on the ceramic substrate 31, and these positioning pins 42 serve as the upper structure 5. The electronic component mounting board 30 and the upper structure 5 are positioned in the horizontal direction by being inserted into the positioning holes 11.

  As shown in FIG. 5, the electronic component mounting substrate 30 has electronic components mounted in a cavity 34 surrounded by a wall portion 32, and the optical element 40 has a raised step surface 36 on the bottom surface of the cavity 34. It is installed. That is, the step surface 36 on which the optical element 40 is mounted is raised from the bottom surface 35 on which other electronic components such as the driver integrated circuit device 41 are mounted, and the upper structure 5 is placed on the wall portion of the electronic component mounting substrate 30. When the optical connection is made by abutting against the upper surface 32 a of the upper structure 32, the vertical distance between the end surface 7 a of the optical fiber 7 of the upper structure 5 and the optical element 40 is such that the upper surface 32 a of the wall portion 32 of the electronic component mounting substrate 30. Are defined by the step surface 36.

  Further, by providing the wall portion 32 on the electronic component mounting substrate 30, other electronic components such as the driver integrated circuit device 41 mounted on the bottom surface 35 lower than the step surface 36 do not protrude upward from the wall portion 32. Thus, the upper structure 5 is brought into contact with the upper surface 32a of the wall portion 32 of the electronic component mounting substrate 30 so that optical connection can be made.

  The height of the stepped surface 36 from the bottom surface 35 can be set to an appropriate height in consideration of the coupling efficiency of the optical connection and the like, and is not particularly limited. For example, it should be several μm to several hundred μm depending on conditions. Can do. The step surface 36 may be formed integrally with the ceramic substrate 31, or the step surface 36 is formed by arranging a step forming member made of a resin material such as polyphenylene sulfide resin or epoxy resin on the ceramic substrate 31. You may make it do.

  When the optical module 1 is assembled from the state where the optical connection and the electrical connection are disconnected as shown in FIG. 1 to the state where the optical connection and the electrical connection are made as shown in FIG. 2, first, the optical module 1 is fixed on the wiring board 70 of FIG. The anisotropic conductive sheet 60 is disposed in the opening 51 of the fitting member 50 that has been made. Next, the electronic component mounting board 30 is disposed thereon, and the upper structure 5 is vertically fitted into the fitting member 50 from above.

  At this time, the positioning pins 42 of the electronic component mounting board 30 are inserted into the positioning holes 11 of the upper structure 5, and the upper structure 5 is in a horizontal direction with respect to the electronic component mounting board 30 with a predetermined accuracy, for example, 3 to 5 μm. In addition, the side surface of the holding member 6 is regulated by the side plate portion 53 of the fitting member 50, and the electronic component mounting substrate 30 is indirectly positioned in the horizontal direction with respect to the wiring substrate 70. Solder bumps having a pitch of 500 μm and a diameter of 300 to 350 μm are formed on the wiring board 70, and a pitch of 500 μm and a diameter of 300 to 350 μm provided on the lower surface of the electronic component mounting board 30 are formed against these solder bumps. The back electrode is aligned.

  Then, the upper structure 5 is pressed downward by the elasticity of the fitting member 50, whereby the anisotropic conductive sheet 60 is pressurized and becomes conductive. Thereby, the back electrode of the electronic component mounting substrate 30 and the solder bump on the wiring substrate 70 are electrically connected via the anisotropic conductive sheet 60.

  Further, the positioning pins 42 of the electronic component mounting substrate 30 are inserted into the positioning holes 11 of the upper structure 5, whereby the end surface 7 a of the optical fiber 7 and the optical element 40 are horizontally aligned as shown in the sectional view of FIG. 6. In addition to the positioning in the direction, the lower surface 6a of the holding member 6 and the upper surface 32a of the wall portion 32 of the optical element mounting substrate 30 come into contact with each other, so that the end surface 7a of the optical fiber 7 Once positioned, they are optically connected.

  As described above, the optical module 1 is electrically and optically connected in the vertical direction in the state shown in FIG. 2 and is capable of transmitting and receiving optical signals transmitted to the outside through the optical fiber 7. The

  For example, during maintenance replacement, the optical connection can be easily disconnected by pulling out the upper structure 5 vertically from the fitting member 50, and then the optical element mounting substrate 30 is removed from the anisotropic conductive sheet 60. Electrical connection can be easily disconnected by taking out vertically.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, as shown in FIG. 7A, the light is incident on the stepped surface 36 raised to the adjacent surface 81 on which the other electronic component 80 is mounted in the cavity 34 of the electronic component mounting substrate 30. Although the element 40 is mounted, depending on the relative thickness of the optical element 40 and the other electronic component 80, as shown in FIG. The optical element 40 may be mounted on the stepped surface 36 that is lowered from the adjacent surface 81 on which is mounted. Thus, by forming the step surface 36 corresponding to the relative thickness of the optical element 40 and the other electronic component 80, the upper structure 5 is not limited by the thickness of the other electronic component 80. The depth of the cavity 34 of the step surface 36 on which the optical element 40 is mounted is appropriately set according to the optical conditions for optical connection between the end face 7a of the optical fiber 7 and the optical element 40 of the electronic component mounting substrate 30. Can be set to

  In the above embodiment, the example in which the electronic component mounting board 30 and the wiring board 70 are electrically connected via the anisotropic conductive sheet 60 has been described. However, the electronic component mounting board 30 and the wiring board 70 are electrically connected to each other. The electrical connection between the electronic component mounting board 30 and the wiring board 70 can be of various structures, such as a structure in which the electronic component mounting board 30 is electrically connected to the wiring board 70 by soldering.

  In the above embodiment, the upper structure 5 is detachably mounted in the vertical direction using the fitting member 50, and the optical transmission path of the upper structure 5 is optically connected to the optical element 40 of the electronic component mounting substrate 30. However, as a mounting structure having such a function, a structure by another mechanism may be used. For example, the wiring board 70 may be provided with a fitting hole, the upper structure 5 may be provided with a latch structure, and the latch structure of the upper structure 5 may be fitted into the fitting hole of the wiring board 70 and attached. Good.

  As the optical element 40, a surface light emitting element other than a VCSEL such as a laser diode may be used, or a surface light receiving element other than a PIN photodiode may be used.

FIG. 1 is a perspective view showing an optical module according to an embodiment of the present invention, and shows a state where an optical connection and an electrical connection are disconnected. FIG. 2 is a perspective view showing a state where optical connection and electrical connection are made in the optical module of FIG. 3A and 3B are views showing the arrangement of the upper member, the optical fiber, and the lower member of the upper structure, in which FIG. 3A is a perspective view and FIG. 3B is a cross-sectional view. FIG. 4 is a perspective view of the electronic component mounting board. FIG. 5 is a cross-sectional view of the electronic component mounting board. FIG. 6 is a cross-sectional view showing a state in which the upper structure and the electronic component mounting substrate are optically connected. FIG. 7 is a partial cross-sectional view of an electronic component mounting board of an optical module according to another embodiment of the present invention.

Explanation of symbols

1 optical module 5 superstructure 6 holding member 6a superstructure of the bottom surface 7 optical fibers 7a end surface 8 tape fiber 10 the upper member 11 positioning hole 12 shoulder 20 lower member 30 the electronic component mounting board 31 ceramic substrate 32 the wall 32a Upper surface 33 Printed wiring 34 Single cavity 35 Bottom surface 36 Step surface 40 Optical element 41 Driver integrated circuit device 42 Positioning pin 50 Fitting member 51 Opening portion 52 Projection portion 53 Side plate portion 54 Protrusion portion 60 Anisotropic conductive sheet 65a External Side optical axis 65b Optical element side optical axis 70 Wiring board 80 Other electronic components 81 Adjacent surface

Claims (3)

An optical module that optically connects an optical fiber that transmits an optical signal and an optical element that converts the optical signal into an electrical signal or converts the electrical signal into an optical signal,
The optical axis is bent so that the optical axis on the outer side and the optical axis on the optical element side are substantially perpendicular to each other and the end face of the optical fiber is flush with the bottom surface of the upper structure. An upper structure having a holding member for holding the fiber ;
An electronic device in which a plurality of electronic components including an optical element are mounted, and the upper structure is positioned on the upper side so that the optical fiber of the upper structure is optically connected to the optical element, and is detachably disposed. and the component mounting board, equipped with a,
In the electronic component mounting board, the electronic component is mounted in a single cavity bounded by a wall which is erected on the substrate,
The concave portion constituting the single cavity surrounded by the wall portion erected on the electronic component mounting substrate has a step surface (36) having a first depth from the upper surface of the wall portion, and the step surface. An adjacent surface (81) that is adjacent and positioned deeper than the step surface,
The optical element (40) has a first thickness and is disposed on the step surface.
The said other electronic component (80) is thicker than the said optical element, and is arrange | positioned at the said adjacent surface, The optical module characterized by the above-mentioned . An optical module that optically connects an optical fiber that transmits an optical signal and an optical element that converts the optical signal into an electrical signal or converts the electrical signal into an optical signal,
The optical axis is bent so that the optical axis on the outer side and the optical axis on the optical element side are substantially perpendicular to each other and the end face of the optical fiber is flush with the bottom surface of the upper structure. An upper structure having a holding member for holding the fiber ;
An electronic device in which a plurality of electronic components including an optical element are mounted, and the upper structure is positioned on the upper side so that the optical fiber of the upper structure is optically connected to the optical element, and is detachably disposed. and the component mounting board, equipped with a,
In the electronic component mounting board, the electronic component is mounted in a single cavity bounded by a wall which is erected on the substrate,
The concave portion constituting the single cavity surrounded by the wall portion erected on the electronic component mounting substrate has a step surface (36) having a first depth from the upper surface of the wall portion, and the step surface. An adjacent surface (81) located adjacent and shallower than the step surface,
The optical element (40) has a first thickness and is disposed on the step surface.
The said other electronic component (80) is thinner than the said optical element, and is arrange | positioned at the said adjacent surface, The optical module characterized by the above-mentioned. Within the single cavity,
The optical module according to claim 1, wherein an upper surface of the optical element and an upper surface of the other electronic component are arranged so as to be substantially flush with each other.

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