JP2005347606A - Optical transceiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transceiver wherein its cost is reduced and its optical coupling is stabilized. <P>SOLUTION: With respect to the optical transceiver, an opening 2 for inserting thereinto an optical connector is formed in its metal housing 1, and in order to hold its light emitter and its light receiver in a predetermined position facing the opening 2, its light emitting portion and its light receiving portion are so mounted on a holder 4 as to integrate the holder 4 into the housing 1. Further, in the optical transceiver, a flange 5 for clogging therewith the opening 2 is so formed in the holder 4 as to make the flange 5 conductive. Therefore, the flange 5 operates as an electromagnetic shield and prevents the rotation of the holder 4. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical transceiver in which an opening for an optical connector is electromagnetically shielded, and relates to an optical transceiver that reduces costs and stabilizes optical coupling.

  An optical transceiver used for optical communication accommodates a light-emitting unit and a light-receiving unit composed of a light-emitting element and a light-receiving element, and a substrate on which a circuit for electrically processing an optical signal transmitted and received by the light-emitting unit and the light-receiving unit is mounted. Therefore, an opening for inserting an optical connector at the end of the optical fiber cord is formed in the casing for connection with an optical fiber cord which is an optical transmission line. Since the light emitting unit and the light receiving unit need to be optically coupled to the optical connector, the light emitting unit and the light receiving unit are accommodated in predetermined positions facing the opening.

  The light emitting unit and the light receiving unit are small parts, and the light emitting unit and the light receiving unit are attached to a holder with a collar in order to position the small part correctly and accommodate it in the case. A fitting portion to be fitted is formed.

  On the other hand, with high-speed communication, high-frequency noise entering and exiting from a light emitting unit, a light receiving unit, a circuit, etc. becomes a problem. Therefore, shielding is achieved by forming the casing with a conductor such as metal. However, since the opening is not shielded even if the casing is made of metal, a sheet of conductor is also put on the holder.

  FIG. 6 shows a background art optical transceiver. As shown in FIG. 6A, in the background art optical transceiver, in order to insert a prismatic optical connector into a metal casing 61, a rectangular opening 62 is formed as viewed from the optical connector insertion direction. In order to hold the light emitting part (not shown; hidden behind the light receiving part) and the light receiving part 63 at a predetermined position facing the opening 62, the light emitting part and the light receiving part are attached to a holder 64 with a collar, The housing 61 is formed with a fitting portion (not shown) into which the collar 65 is fitted. The light emitting / light receiving unit 63 and the circuit board 66 are electrically connected by a flexible board (not shown).

  The light emitting part and the light receiving part 63 are each formed in a cylindrical shape. The holder 64 is attached to the ends of the light emitting unit and the light receiving unit. The holder 64 includes a large-diameter portion for attaching the light-emitting portion and the light-receiving portion and a small-diameter portion that is inserted into an optical connector (not shown). The shape of the large diameter portion and the small diameter portion viewed from the optical connector insertion direction is circular. Two flanges 65 are formed in a portion having a large diameter by providing a groove 69 that goes around.

  Although not shown in the drawing, the opening 62 extends to reach the collar 65 of the holder 64 to form a space for inserting the optical connector.

  The fitting between the collar 65 and the fitting portion is such that the fitting portion is recessed when the collar 65 protrudes radially outward, and the fitting portion protrudes radially inward at the groove 69. ing. When both are fitted together, the light emitting part and the light receiving part 63 are assembled at predetermined positions from the opening 62. On the other hand, the collar 65 is the same as the holder 64 when viewed from the opening 62 so that the center line of the opening 62 (optical axis of the optical connector) and the center line of the holder 64 (optical axes of the light emitting part and the light receiving part) coincide. It is formed in a circle with a center. Therefore, if the holder 64 is assembled at an arbitrary rotation angle around the center line of the holder 64, the light coupling unit and the light receiving unit can be optically coupled to the optical connector.

  A metal sheet 67 is attached to the holder 64. As shown in FIG. 6B, the metal sheet 67 has a circular hole through which a small diameter portion of each of the light emitting part and light receiving part holders 64 is inserted. The metal sheet 67 covers a large diameter portion around a small diameter portion of the holder. A fin 68 is formed on the metal sheet 67 so as to be in contact with the housing 61. The fin 68 protrudes from the collar 65 and comes into contact with the housing 61, whereby the metal sheet 67 is grounded and exhibits an electromagnetic shielding effect at the opening 62.

US Pat. No. 6,609,838 B1 US Pat. No. 6,350,063 B1

  When manufacturing the optical transceiver of the background art, first, the light emitting unit and the light receiving unit 63 are mounted on the holder 64, the metal sheet 67 is mounted on the holder 64, and the holder 64 is assembled in the housing 61. At this time, since there is a step of attaching the metal sheet 67 to the holder 64, the time required for the work is increased accordingly.

  Further, when the metal sheet 67 is attached to the holder 64, the metal sheet 67 may be bent, which makes it difficult to incorporate the holder 64 into the housing 61. Care must be taken that the metal sheet 67 is not bent. However, the work for preventing the thin and small metal sheet 67 from being bent is not workable.

  Moreover, the number of parts increases by inserting the metal sheet 67.

  As described above, incorporating the metal sheet 67 for electromagnetic shielding causes a problem in terms of workability and the number of parts.

  Further, the optical transceiver according to the background art has a degree of freedom in which the holder 64 can rotate around the center line with respect to the housing 61. However, when the flexible substrate connecting the light emitting unit and the light receiving unit 63 and the circuit board 66 is twisted, the optical coupling between the light emitting unit and the light receiving unit and the optical connector is shifted due to the twisting force, and the optical connection loss increases. As a result, the optical signal transmission becomes unstable and a transmission error occurs.

  Accordingly, an object of the present invention is to provide an optical transceiver that solves the above-described problems, reduces costs, and stabilizes optical coupling.

  In order to achieve the above object, the present invention forms an opening for inserting an optical connector in a metal casing, and holds the light emitting part and the light receiving part at a predetermined position facing the opening. In an optical transceiver in which a light emitting part and a light receiving part are mounted on a holder and the holder is incorporated in the housing, a collar is formed on the holder to close the opening, and the collar is made conductive. is there.

  A protrusion that contacts the housing may be formed on the collar.

  A protrusion that contacts the collar may be formed in the housing.

  The present invention exhibits the following excellent effects.

  (1) The workability of assembly is improved and the number of parts is reduced, so that the cost can be reduced.

  (2) Since the holder has no degree of freedom of rotation, optical coupling can be stabilized.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, an optical transceiver according to the present invention forms a rectangular opening 2 for inserting a prismatic optical connector in a metal casing 1 and a predetermined position facing the opening 2. In order to hold the light emitting part (not shown; hidden behind the light receiving part 3) and the light receiving part 3, the light emitting part and the light receiving part 3 are attached to the holder 4 and the holder 4 is incorporated in the housing 1 In this optical transceiver, a square (rectangular) collar 5 that closes the opening 2 is formed in the holder 4, and the collar 5 is made conductive. The light emitting / light receiving unit 3 and the circuit board 6 are electrically connected by a flexible substrate (not shown).

  The optical transceiver of FIG. 1 differs greatly from the optical transceiver of the background art in that a square collar 5 is formed on the holder 4 and the collar 5 is made conductive. In the following, these differences will be described with emphasis.

  As a specific configuration for imparting conductivity to the collar 5, a conductive paint is applied to the holder 4 made of resin (the collar 5 is also integrally formed), and a metal such as copper or nickel is applied to the holder 4 made of resin. In some cases, the holder 4 is formed by mixing a conductive material such as carbon black powder or magnetic powder such as ferrite into the resin.

  In order to clarify the overall shape of the holder 4, a perspective view of the holder 4 is shown in FIG. As shown in the figure, the holder 4 is connected to a small diameter portion 7 to be inserted into an optical connector (not shown), a rectangular collar 5 as viewed from the optical connector insertion direction, that is, a square collar 5, and the collar 5. A portion 8 for attaching the light emitting portion and the light receiving portion is provided. The small diameter portion 7 has a circular shape when viewed from the optical connector insertion direction.

  Protrusions 9 and 10 for making contact with the housing 1 are formed around the collar 5 (upper and lower surfaces, both side surfaces, or both). The protrusions 9 and 10 are wedge-shaped, and the height protruding from the collar 5 is high on one end face side, and is low to the extent that there is almost no height from the collar 5 on the opposite end face side. Although not visible in this figure, a circular hole for inserting and attaching a part of the cylindrical light emitting part and the light receiving part is formed on the opposite end surface of the holder 4. If a groove having a width of about 0.5 mm is provided on the inner periphery of the circular hole and a crest that fits in the groove is provided on the outer periphery of the light emitting unit and the light receiving unit, the light emitting unit and It is possible to prevent the light receiving unit from rotating.

  Although not shown in FIG. 1, the opening 2 extends to the position immediately before the circuit board 6 to form a space for inserting the optical connector, a holder 4, a light emitting unit, and a light receiving unit 3. .

  In order to clarify the shape of the collar 5, FIG. 3 shows a view (end view) as seen from the optical connector insertion direction. As shown in the figure, the housing 1 accommodates a holder 4 (left side in the drawing) of the light emitting unit and a holder 4 (right side in the drawing) of the light receiving unit side by side. Both the collars 5 of the holders 4 are formed in a square shape. The holder 4 of the light emitting unit has projections 9 and 10 formed on the upper surface of the collar 5 and the surface (left side in the drawing) in contact with the side wall of the housing 1. On the other hand, the holder 4 of the light receiving portion has protrusions 9 and 10 formed on the upper surface of the collar 5 and the surface (right side in the drawing) in contact with the side wall of the housing 1.

  The housing 1 is divided into a lower chassis 11 and an upper chassis 12. The lower chassis 11 includes a bottom plate 13 that is in contact with the lower surfaces of the flanges 5 of the two holders 4, a partition wall 14 that rises from the bottom plate 13 to partition the two holders 4 and 4, and side walls 15 that rise on both sides of the bottom plate. Consists of. The separation distance between the side wall 15 and the partition wall 14 is substantially the same as the width of the holder 4 (the width of the collar 5). The height of the partition wall 14 is substantially the same as the height of the holder 4 (the height of the collar 5). A guide groove for guiding the protrusion 10 of the collar 5 or a notch hole into which the protrusion 10 is fitted is formed at the end of the side wall 1. When the holder 4 is fitted into the lower chassis 11 from the optical connector insertion direction and pushed in, the holder comes to the position shown in FIG.

  The upper chassis 12 folds inward from the lower ends of the outer side walls 17, the top plate 16 in contact with the upper surfaces of the flanges 5 of the two holders 4, the outer side walls 17 that cover both side walls 1 of the lower chassis 11, and the lower chassis 11. It consists of a claw portion 18 that contacts the bottom plate 13 from the outside. The top plate 16 is formed with a notch for allowing the projection 9 of the collar 4 to escape onto the top plate 16.

  The upper chassis 12 and the lower chassis 11 can be assembled with each other by being fitted and slid. When the lower chassis 11 and the upper chassis 12 are assembled into an integrated housing 1, two openings 2 are formed by the bottom plate 13, the partition wall 14, the side wall 15, and the top plate 16 of the upper chassis 12. The Further, the protrusions 9 on the upper surface of the collar 5 are engaged with the top plate 16, whereby the holder 4 is held in the housing 1.

  The operational effects of the optical transceiver of the present invention will be described.

  As shown in FIG. 3, the collar 5 covers the entire opening 2 (the portion 7 having a small diameter of the holder 4 is naturally excluded because it is a light path). Since the collar 5 is electrically conductive and is in contact with the casing 1 and grounded, the electromagnetic wave can be well shielded. Further, by providing the projections 9 and 10 on the collar 5, the contact between the collar 5 and the housing 1 can be ensured.

  Moreover, since the collar 5 is square and fits exactly in the square opening 2, the holder 4 does not rotate unnecessarily. Furthermore, by providing the projections 9 and 10 on the collar 5, the projections 9 and 10 are engaged with the housing 1, and the holder 4 can be reliably fixed.

  According to the present invention, since the collar 5 which is a part of the holder 4 has a function of electromagnetic shielding, it is not necessary to add a metal sheet. For this reason, the workability of the assembly is improved and the number of parts is reduced. As a result, the cost of the optical transceiver can be reduced.

  Further, according to the present invention, since the collar 5 is square, the holder 4 is prevented from rotating, and the flexible substrate connecting the light emitting unit and the light receiving unit and the circuit board does not twist. As a result, optical coupling can be stabilized and transmission errors due to optical connection loss can be reduced.

  Another embodiment of the present invention will be described with reference to FIGS.

  FIG. 4 shows only the upper chassis 12 of the casing 1 described in FIG. FIG. 5 shows the two holders 4 used in FIG. 3 taken out. In other words, the holder 4 (left side in the drawing) of the light emitting part has protrusions 9 and 10 formed on the upper surface of the collar 5 and the surface (see FIG. 3) in contact with the side wall of the housing. On the other hand, the holder 4 of the light receiving portion has protrusions 9 and 10 formed on the upper surface of the collar 5 and the surface in contact with the side wall of the housing. On the other hand, the upper chassis 12 is provided with opposing protrusions 19 at positions facing the protrusions 9 and 10, respectively. These opposing protrusions 19 project elastically in contact with and interfere with the protrusions 9 and 10 of the collar 5 by protruding inward of the housing. In the illustrated example, a U-shaped cut 20 is formed in the top plate 16 and the outer wall 17 of the upper chassis 12, and a portion surrounded by the cut 20 is inflated to form an opposing projection 19 that functions as a leaf spring. ing.

  These opposing projections 19 are pushed and biased by the projections 9 and 10 of the collar 5, and can hold the collar 5 strongly.

It is a side perspective view of the optical transceiver which shows one Embodiment of this invention. It is a perspective view of the holder which shows one Embodiment of this invention. It is the end elevation which looked at the optical transceiver of Drawing 1 from the optical connector insertion direction. It is a perspective view of the upper chassis which shows other embodiment of this invention. It is a perspective view of the holder which shows other embodiment of this invention. (A) is side perspective drawing of the optical transceiver of background art, (b) is a front view of a metal sheet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Opening part 4 Holder 5 Brim 9,10 Protrusion 19 Opposite protrusion

Claims (3)

  An opening for inserting the optical connector is formed in the metal housing, and in order to hold the light emitting unit and the light receiving unit at a predetermined position facing the opening, the light emitting unit and the light receiving unit are attached to the holder, An optical transceiver in which the holder is incorporated in the housing, wherein a collar that closes the opening is formed in the holder, and the collar is made conductive.   The optical transceiver according to claim 1, wherein a protrusion that contacts the housing is formed on the collar. The optical transceiver according to claim 1, wherein a protrusion that contacts the collar is formed in the casing.

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