JP2012242691A - Optical fiber socket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber socket, that simplifies optical axis alignment between an optical fiber and a photoelectric conversion element by using high dimensional precision, and allows material costs to be reduced and a mounting operation to be simplified.SOLUTION: An optical fiber socket 1 has a circuit block 5 and a sleeve block 6, which are positioned by fitting a fitting projection 61 of the sleeve block 6 to a fitting hole 41 of the circuit block 5. The fitting projection 61 of the sleeve block 6 and a sleeve 62 are integrally resin molded. A light transmission section 63 is formed of a material different from that of the fitting projection 61 and the sleeve 62, for example highly heat-resistant resin or glass. The sleeve 62 is not limited to a light transmissive material, but can be composed of a material that is suitable for formation with high dimensional precision. Cost reduction is achieved by restricting use of expensive light transmission materials to the light transmission section only. The light transmission section 63 is formed of a material that can withstand a temperature of solder reflow mounting, and mounting of the socket 1 to a mounting board can be performed at the same time as other electric components are being mounted.

Description

  The present invention relates to an optical fiber socket into which a ferrule fitted to the tip of an optical fiber is inserted.

  2. Description of the Related Art Conventionally, a light having a substrate on which a photoelectric conversion element is mounted and a sleeve that is fitted and positioned on the substrate, and in which a ferrule is inserted into the sleeve and optical fiber and the photoelectric conversion element are optically coupled in use. A fiber socket is known (for example, see Patent Document 1). In this socket, two fitting holes are formed in the board, two fitting shafts are provided on the surface of the sleeve facing the board, and the two fitting shafts are fitted into the two fitting holes, respectively. Thus, the fitting positioning of the substrate and the sleeve is performed.

JP-A-8-5872

  However, in the conventional optical fiber socket as described above, the relationship between the dimensional accuracy and the material cost, the working efficiency when mounting the socket itself, and the like are not considered. Corresponding to the speeding up of communication and the miniaturization of communication equipment, it is desired that other electrical components are mounted, or that an optical fiber socket can be efficiently mounted together with those electrical components on a mounted substrate.

  The present invention solves the above-described problem, and can simplify the optical axis alignment work between the optical fiber and the photoelectric conversion element, reduce the material cost, and simplify the mounting work. An object is to provide a socket for a fiber. Furthermore, an object of the present invention is to provide an optical fiber socket capable of improving the accuracy of optical axis alignment.

  In order to achieve the above object, an optical fiber socket according to the present invention includes a photoelectric conversion element, a circuit board on which the photoelectric conversion element is mounted, and a molding in which a plurality of fitting holes are provided and is integrally formed with the circuit board. A circuit block having a member, a plurality of fitting protrusions fitted in a plurality of fitting holes, a sleeve into which a ferrule fitted to the tip of the optical fiber is inserted, and an axis of the sleeve A circuit block having mounting electrodes electrically connected to the circuit board, and the circuit block and the sleeve block are fitted into the fitting holes of the circuit block. Are fitted so that the optical axis of the photoelectric conversion element and the axis of the sleeve coincide with each other, and the photoelectric conversion element is hollow-sealed by the sleeve block, , Characterized in that it is formed of a material different from the material of the sleeve.

  In this optical fiber socket, the light transmission part is preferably formed of a material that can withstand the temperature of solder reflow mounting.

  In this optical fiber socket, the light transmission part is preferably formed of glass.

  In this optical fiber socket, it is preferable that the light transmitting portion is a lens, and both surfaces of the optical axis region are formed in parallel planes.

  In this optical fiber socket, it is preferable that the light transmitting portion is integrally formed with the sleeve by insert molding.

  In this optical fiber socket, it is preferable that an electromagnetic shield member is provided on the outer peripheral portion of the light transmitting portion.

  According to the optical fiber socket of the present invention, since the light transmitting portion and the sleeve are formed of different materials, the sleeve is made of a material with high dimensional accuracy, so that alignment work is unnecessary, and generally an expensive light transmitting material. The material cost can be reduced by limiting the use of only to the light transmitting portion. In addition, since the material for the light transmitting portion and the sleeve can be individually selected, a range of material selection suitable for mounting is widened, and a socket that can simplify mounting work can be easily realized. Furthermore, since the fitting protrusion of the sleeve block is fitted into the fitting hole provided in the molded member, it is possible to improve the accuracy of optical axis alignment between the optical axis of the photoelectric conversion element and the axis of the sleeve.

(A) is sectional drawing about the socket for optical fibers which concerns on one Embodiment of this invention, (b) is sectional drawing in the other sectional position of the socket. (A) is an exploded perspective view of the socket, (b) is a perspective view of the socket. (A) is sectional drawing of the modification of the socket, (b) is sectional drawing in the other sectional position of the modification. Sectional drawing of the light transmission part periphery of the other modification of the socket. (A) is sectional drawing of the periphery of the light transmissive part which shows the optical path in case the photoelectric conversion element of the modification is a light emitting element, (b) is sectional drawing when the position of the light emitting element in (a) shifts. (A) is sectional drawing of the periphery of the light transmission part which shows the optical path in case the photoelectric conversion element of the modification is a light receiving element, (b) is sectional drawing when the position of the light receiving element in (a) shifts. Sectional drawing of the further another modification of the socket. (A) is sectional drawing of the other modification of the socket, (b) is sectional drawing in the other cross-sectional position of the modification.

  Hereinafter, an optical fiber socket (hereinafter referred to as a socket) according to an embodiment of the present invention will be described with reference to the drawings. FIGS. 1A and 1B and FIGS. 2A and 2B show a socket 1 according to this embodiment. The socket 1 is configured by combining a circuit block 5 and a sleeve block 6. The circuit block 5 includes a photoelectric conversion element 2, a circuit board 3 on which the photoelectric conversion element 2 is mounted, a sleeve receiving member 4 that is a molded member integrally formed with the circuit board 3 by providing two fitting holes 41, a circuit And a mounting electrode 14 electrically connected to the substrate 3. The sleeve block 6 includes two fitting protrusions 61 that fit into the fitting holes 41, a sleeve 62, and a light transmission portion 63 disposed on the axis L of the sleeve 62. The sleeve 62 has a circular through-hole 62 a for inserting a ferrule 8 a fitted to the tip of the optical fiber 8. The circuit block 5 and the sleeve block 6 are positioned with each other by fitting the fitting protrusion 61 of the sleeve block 6 into the fitting hole 41 of the circuit block 5.

  The photoelectric conversion element 2 may be either a light emitting element or a light receiving element. The circuit board 3 is a board provided with a wiring pattern, and the wiring pattern includes a signal line and a ground line for signal transmission to the photoelectric conversion element 2 or signal reception from the photoelectric conversion element 2. The sleeve receiving member 4 is a member that receives the sleeve block 6 and is resin-molded with the circuit board 3 inserted, for example, by insert molding. As the resin for the sleeve receiving member 4, a thermoplastic resin or a thermosetting resin can be used, and glass fibers may be included. The sleeve receiving member 4 has a quadrangular outer shape, has a circular recess 42 on the upper surface thereof, and two circular fitting holes 41 penetrating through the bottom surface of the circular recess 42 are symmetrical with respect to the central axis of the circular recess 42. Is provided.

  In the circuit board 3, a part of the surface of the circuit board 3 is exposed on the bottom surface of the circular recess 42, and a part of the circuit board 3 protrudes outward from the side surface of the sleeve receiving member 4. A mounting electrode 14 for surface mounting is provided on the protruding portion. Note that only the mounting electrode 14 may be projected without projecting the circuit board 3 (see FIG. 8B). The bottom surface of the circular recess 42 and the exposed portion of the circuit board 3 constitute the same plane. The photoelectric conversion element 2 is mounted on the exposed portion of the circuit board 3 in the circular recess 42. The mounting position of the photoelectric conversion element 2 is the mounting position where the optical axis position of the photoelectric conversion element 2 is arranged at the center position of the circular recess 42, more precisely, at the midpoint position between the centers of the two circular fitting holes 41. It is. Here, the optical axis position of the photoelectric conversion element 2 is a light emission center position when the photoelectric conversion element 2 is a light emitting element, for example, a light emission intensity maximum position. It is the maximum position.

  In the sleeve block 6, the fitting protrusion 61 and the sleeve 62 are integrally molded with resin, and the light transmitting portion 63 is formed of a material different from the material of the fitting protrusion 61 and the sleeve 62. The two fitting protrusions 61 are provided symmetrically with respect to the axis L of the sleeve 62 on the lower surface of the sleeve 62. The sleeve 62 has a two-stage coaxial cylindrical shape whose outer shape is thin at the top and thin at the bottom, and has a through-hole 62a coaxial with the outer shape, and the lower part of the through-hole 62a has an enlarged diameter. A light transmitting portion 63 is retrofitted to the enlarged portion using the adhesive resin 10. The light transmissive portion 63 has a parallel flat disk shape with a constant thickness, and may be formed using a thermoplastic resin or a thermosetting resin, for example, a high heat resistant resin such as polyimide or crosslinked nylon as a material. It can also be made of glass. These materials are selected from optical materials that transmit laser light having a specific wavelength corresponding to the characteristics of the photoelectric conversion element 2, for example, 850 nm.

  The process of assembling the socket 1 will be described. After the sleeve receiving member 4 formed integrally with the circuit board 3 is formed, the photoelectric conversion element 2 is mounted on the circuit board 3. When the photoelectric conversion element 2 is mounted, the center positions of the two fitting holes 41 are acquired using, for example, an imaging device of a chip mounter. As a method for detecting a circle and its center position by image processing, for example, Hough transformation can be used. Here, the dimension of each part is illustrated. The photoelectric conversion element 2 is, for example, a bare chip, and its planar dimension is about □ 0.3 (0.3 mm × 0.3 mm), and the interval between the two fitting holes 41 is about 4 mm. Therefore, the measurement accuracy of the circular shape and the center position can be increased by imaging a small area including the two fitting holes 41 at a high magnification without increasing the processing load. For example, measurement accuracy and positioning accuracy can be increased to an accuracy of about 10 μm. Using the center positions of the two fitting holes 41 as a reference, the photoelectric conversion element 2 is positioned at the midpoint position, that is, the optical axis position of the photoelectric conversion element 2 is positioned. Thereby, the photoelectric conversion element 2 is mounted on the circuit board 3, and the circuit block 5 is completed. The sleeve block 6 is completed by attaching a separately formed light transmitting portion 63 to a sleeve 62 resin-molded together with the fitting protrusion 61.

  The socket 1 is completed by fitting the sleeve block 6 to the circuit block 5. This fitting is completed by fitting the fitting projection 61 into the fitting hole 41, inserting the lower portion of the sleeve 62 into the circular recess 42, and bringing the bottom surface of the circular recess 42 into contact with the bottom surface of the sleeve 62. As a result, the optical axis L of the photoelectric conversion element 2 and the axis L of the sleeve 62 coincide with each other, and the photoelectric conversion element 2 is hollowly sealed by the sleeve block 6. If necessary, the sealing or adhesive fixing resin 10 may or may not be filled in the gap between the fitting part and the insertion part.

  The dimensional accuracy of each component of the socket 1 is such that the assembled socket 1 can ensure a predetermined assembly accuracy only by positioning accuracy by fitting. That is, each fitting hole 41 and each fitting protrusion 61 are formed with dimensional accuracy that can achieve hollow sealing and optical axis adjustment with respect to the photoelectric conversion element 2 at the time of fitting. Further, the dimensional accuracy of the through-hole 62 a of the sleeve 62 and the positional accuracy of the axis L are set to a predetermined assembly accuracy with respect to the optical axis position of the photoelectric conversion element 2. Therefore, the optical axis alignment and optical coupling between the optical fiber 8 and the photoelectric conversion element 2 can be performed by so-called passive alignment only by inserting the ferrule 8a into the sleeve 62, and the optical signal level is monitored by the measuring device. However, active alignment to be performed becomes unnecessary.

  Each dimensional accuracy of the socket 1 is based on the dimensional accuracy of each fitting member by resin molding and the mounting position accuracy of the photoelectric conversion element 2 by image processing. The fitting hole 41 of the sleeve receiving member 4 can be formed when the sleeve receiving member 4 is formed, and the maximum forming accuracy that can be realized by the forming technique is 1 μm or less. Accuracy and position accuracy can be achieved. The resin molding dimensional accuracy of the sleeve 62 of the sleeve block 6, its through-hole 62a, and the fitting protrusion 61 is the same as described above.

  According to the optical fiber socket of the present invention, since the light transmitting portion and the sleeve are formed of different materials, the sleeve can be formed of a material suitable for molding with high dimensional accuracy without being limited to the light transmitting material. This makes alignment work unnecessary. Further, since the use of an expensive light transmitting material can be limited to only the light transmitting portion, the material cost can be reduced. In addition, in order to perform resin molding with the highest molding accuracy easily and at low cost, it is important to select a molding resin. By forming the light transmitting portion 63 from a material different from the material of the sleeve 62, molding resin is formed. The special effect that the selection freedom of can be expanded is produced. That is, since the materials for the light transmission part and the sleeve can be individually selected, the range of material selection suitable for mounting is widened, and a socket that can simplify the mounting operation can be easily realized. In the socket 1, the light transmission part 63 can be formed of a material that can withstand the temperature of solder reflow mounting. Moreover, the light transmission part 63 can be formed with the glass which can endure the temperature of solder reflow mounting. Such a socket 1 has a configuration that can withstand the temperature of solder reflow mounting as a whole, and can be efficiently mounted on a mounting substrate on which other electrical components are mounted together with those electrical components by solder reflow mounting.

  3A and 3B show a modification of the socket 1. In this modification, an electromagnetic shield member 64 is provided on the outer peripheral portion of the light transmitting portion 63. The electromagnetic shield member 64 is a ring-shaped metal that supports the light transmitting portion 63 housed in the enlarged diameter portion below the through-hole 62a from below and surrounds the photoelectric conversion element 2 mounted on the circuit board 3. Provided with. Since the electromagnetic shield member 64 is a resilient ring that expands and contracts in the radial direction, the biasing force allows the electromagnetic shield member 64 to be self-held in the enlarged diameter portion below the through-hole 62a. Can be used as When the photoelectric conversion element 2 is a light emitting element, the electromagnetic shielding member 64 shields high frequency noise generated during light emission from propagating to the outside. When the photoelectric conversion element 2 is a light receiving element, Noise mixing can be prevented and the light receiving sensitivity can be improved. The electromagnetic shield member 64 may be electrically grounded or may be at a floating potential without being grounded. The electromagnetic shield member 64 may be a ring-shaped member 64 that does not have an electromagnetic shield function. Such a member 64 serves as a support member that supports the light transmission portion 63 from below. The light transmitting portion 63 serves as a cover for covering the photoelectric conversion element 2. Such a supporting member 64 and the electromagnetic shielding member 64 are provided from the ferrule 8 a to the light transmitting portion 63 when the ferrule 8 a is inserted. It functions as a cover stopper that counters the acting force.

  4, 5, and 6 show another modification of the socket 1. As shown in FIG. 4, the socket 1 of this embodiment is a lens in which the light transmitting portion 63 is a lens and both surfaces of the optical axis region A are formed in parallel planes. That is, considering the mounting variation of the photoelectric conversion element 2 and the molding variation of the light transmitting portion 63, the range of the optical axis region A in the central portion remains flat, and the peripheral portion thereof has a curved lens shape. The light transmitting portion 63 has no lens effect in the optical axis region A, and operates as a lens in the peripheral portion of the optical axis region A. Such a light transmission part 63 condenses the light deviating from the optical axis region A in the optical axis direction. As shown in FIG. 5A, such a light transmission part 63 is such that the photoelectric conversion element 2 is a light emitting element, and the three optical axes of the optical fiber 8, the light transmission part 63, and the photoelectric conversion element 2 are When they are aligned, they operate in the same manner as the light transmission part 63 of the parallel plate in the above-described embodiment shown in FIGS. Usually, the light emitting portion 2 a of the photoelectric conversion element 2 is regarded as a substantially point light source, and a part of light from the light emitting portion 2 a is received by the optical fiber 8. For example, as shown in FIG. 5B, when the position of the photoelectric conversion element 2 is deviated from the optical axis position of the light transmitting portion 63, the light deviating from the optical axis region A of the light transmitting portion 63 is The light is deflected in the direction of the optical axis of the light transmitting portion 63 by the condensing effect of the lens of the light transmitting portion 63. That is, even if a deviation occurs in the mounting position of the photoelectric conversion element 2, the light transmission characteristic loss can be improved by the compensation function of the light transmitting portion 63, and the optical coupling between the photoelectric conversion element 2 and the optical fiber 8 can be performed more reliably.

  In the case where the photoelectric conversion element 2 is a light receiving element, in addition to the state in which the optical axes are aligned as shown in FIG. The positional shift of the conversion element 2 is compensated, and the optical coupling between the photoelectric conversion element 2 and the optical fiber 8 can be performed more reliably. Usually, the light receiving portion 2 b of the conversion element 2 receives a part of the light emitted from the entire surface of the optical fiber 8 and can receive more light by the lens effect of the light transmitting portion 63.

  7, 8 (a), and 8 (b) show still another modification of the socket 1. In these sockets 1, the light transmitting portion 63 is integrally formed with the sleeve 62 by insert molding. The socket 1 shown in FIG. 7 is obtained by insert-molding a light-transmitting portion 63 having a parallel flat disk shape. The socket 1 shown to Fig.8 (a) (b) insert-molds the light transmissive part 63 which forms a lens. The socket 1 has a mounting electrode 14 for surface mounting projecting outward from two side surfaces of the sleeve receiving member 4 facing each other. Since the mounting electrode 14 is provided on both sides of the sleeve receiving member 4, the socket 1 is mounted as compared to the case where the mounting electrode 14 is provided in a cantilever manner as shown in FIG. The mechanical strength of the socket 1 is further enhanced.

  The present invention is not limited to the above-described configuration, and various modifications can be made. For example, the configurations of the above-described embodiments can be combined with each other. For example, the electromagnetic shield member 64 can be provided in the socket 1 shown in FIGS. Further, the number of the fitting holes 41 and the fitting protrusions 61 is not limited to two, and a plurality of fitting holes 41 and fitting protrusions 61 can be provided, and the shapes thereof can be any shapes that can be fitted to each other.

DESCRIPTION OF SYMBOLS 1 Optical fiber socket 2 Photoelectric conversion element 3 Circuit board 31 Mounting electrode 4 Sleeve receiving member (molding member)
41 fitting hole 5 circuit block 6 sleeve block 61 fitting projection 62 sleeve 63 light transmission part 64 electromagnetic shield member 8 optical fiber 8a ferrule L axis, optical axis

Claims (6)

A photoelectric conversion element;
A circuit block on which the photoelectric conversion element is mounted, and a circuit block having a molding member provided with a plurality of fitting holes and integrally formed with the circuit board;
A plurality of fitting protrusions which are respectively fitted into the plurality of fitting holes, a sleeve into which a ferrule fitted to the tip of the optical fiber is fitted, and a light transmitting portion arranged on the axis of the sleeve. A sleeve block,
The circuit block has a mounting electrode electrically connected to the circuit board,
The circuit block and the sleeve block are positioned so that the fitting projection of the sleeve block is fitted into the fitting hole of the circuit block so that the optical axis of the photoelectric conversion element and the axis of the sleeve coincide with each other, and , The photoelectric conversion element is hollow-sealed by the sleeve block,
The optical fiber socket, wherein the light transmission part is formed of a material different from a material of the sleeve.   The optical fiber socket according to claim 1, wherein the light transmission portion is formed of a material that can withstand a temperature of solder reflow mounting.   The optical fiber socket according to claim 1, wherein the light transmission portion is made of glass.   4. The optical fiber socket according to claim 1, wherein the light transmitting portion is a lens, and both surfaces of the optical axis region are formed in parallel planes. 5.   The optical fiber socket according to any one of claims 1 to 4, wherein the light transmitting portion is integrally formed with the sleeve by insert molding.   The optical fiber socket according to any one of claims 1 to 5, further comprising an electromagnetic shield member on an outer peripheral portion of the light transmission portion.

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