JP2006154084A - Optical transmission apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical transmission apparatus in which optical coupling efficiency is stable and high between an optical element and an optical fiber with a small core diameter. <P>SOLUTION: The apparatus is equipped with a lead frame 11, an optical element 15 mounted on the surface of the lead frame 11, a translucent resin 21 for sealing the optical element 15 and a part of the lead frame 11, and a sleeve 31 which is fixed at one end in the translucent resin 21 portion oppositely facing the optical element 15 and which is for internally installing an optical fiber 42 attachably and detachably. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a resin-molded optical transmission apparatus that performs optical transmission via an optical fiber or the like.

  In optical communication, the use of optical transmission devices responsible for medium-to-short-distance and medium-low-speed optical fiber transmission is expanding as communication information increases. Along with this expansion of applications, optical transmission devices are required to have low power and long transmission distances. In order to reduce power consumption and increase the distance, an optical transmission device needs to efficiently introduce light from a light emitting element into an optical fiber or efficiently receive light transmitted from the optical fiber.

  Conventionally, in an optical transmission device, for example, a light emitting element or a light receiving element (hereinafter, a light emitting element and a light receiving element of a tree are collectively referred to as an optical element) is mounted on a lead frame and sealed with a transparent resin. This optical transmission device is housed in a receptacle (envelope) having an insertion port (sleeve) for inserting an end portion of an optical fiber for transmitting an optical signal to constitute an optical transmission device (optical transmission module) ( For example, see Patent Document 1.)

  In an optical transmission module, in order to make an optical signal efficiently enter the end portion of the optical fiber, it is important to align the optical element with the sleeve in which the end portion of the optical fiber is provided. The optical signal coupling efficiency increases as the center of the end of the optical fiber, that is, the center axis of the sleeve and the center of the optical element coincide. Conversely, if these axes are shifted, the transmitted light emitted by the light emitting element cannot be sufficiently introduced into the optical fiber, or in the case of the light receiving element, it cannot be sufficiently received from the optical fiber.

  However, in the above-described prior art, since the optical transmission device that houses the optical element and the envelope to which the sleeve is fixed are produced as separate parts and combined to form an optical transmission module, the optical transmission device is When it is inserted into the container and fixed, it causes a large deviation between the center of the optical element and the central axis of the sleeve. That is, in order to store the optical transmission device in the storage unit of the envelope, a clearance is required so that the optical transmission device can be smoothly inserted. With this clearance, for example, when the optical transmission device is fixed with an adhesive, the optical transmission device is attached to the envelope. On the other hand, tilt and misalignment occur.

  In addition, due to burrs or the like left around the translucent resin of the optical transmission device, the outer dimensions become large, and the optical transmission device can be aligned even if pressed against the contact surface of the housing housing portion. May deviate from the design position. As a result, there is a deviation between the center of the optical element and the central axis of the sleeve. In particular, when the optical transmission device is optically coupled to an optical fiber having a small core diameter, the optical coupling efficiency varies and the defect rate increases. was there.

In recent years, for example, a silica glass fiber having a smaller optical fiber core diameter of 50 μm may be used in response to the demand for high-speed transmission, and ensuring optical coupling efficiency is becoming increasingly important.
JP 2002-344024 A (page 5, FIG. 5)

  The present invention provides an optical transmission apparatus in which the optical coupling efficiency between an optical element and an optical fiber having a small core diameter is stable and high.

  An optical transmission device according to one embodiment of the present invention includes a substrate, an optical element mounted on a surface of the substrate, a translucent resin that seals the optical element and a part of the substrate, and the optical element. One end portion is embedded and fixed in the translucent resin portion, and a sleeve for detachably placing an optical fiber is provided.

  According to the present invention, it is possible to provide an optical transmission device in which the optical coupling efficiency between an optical element and an optical fiber having a small core diameter is stable.

  Embodiments of the present invention will be described below with reference to the drawings. In the figure shown below, the same code | symbol is attached | subjected to the same component.

  An optical transmission apparatus according to Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 schematically shows the structure of an optical transmission device. FIG. 1A is a plan view, and FIG. 1B is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 1, an optical transmission apparatus 1 includes a lead frame 11 as a substrate, an optical element 15 as a light emitting element mounted on the surface of the lead frame 11, an optical transmission IC 16 for driving the optical element 15, and a lead frame. 11 and a translucent resin 21 that seals the optical element 15, and one end of the translucent resin 21 that opposes the optical element 15, and a sleeve for detachably placing an optical fiber 31 is provided.

  The lead frame 11 has a die pad portion 12, an inner lead portion 13 disposed in the translucent resin 21, and an external terminal 14 led out of the translucent resin 21, and is made of a material such as Cu or FeNi alloy. It is plated as necessary.

  The optical element 15 includes a light emitting diode or a surface emitting laser diode (LD) that emits transmission light having a desired wavelength, and is a lead frame that is separated from a reference point (not shown) of the lead frame 11 by a certain distance. 11 is fixed to a predetermined position on the die pad portion 12 with a conductive material.

  The optical transmission IC 16 that drives the optical element 15 is fixed on the die pad portion 12 of the lead frame 11 adjacent to the optical element 15.

  The optical element 15 and the optical transmission IC 16 are electrically connected to the inner lead portion 13 of the lead frame 11 by, for example, an Au wire 18, and are electrically connected to each other via the wire 18 and the lead frame 11. Yes. The optical element 15 and the optical transmission IC 16 are electrically connected to an external circuit via the external terminal 14 of the lead frame 11 led out of the translucent resin 21.

  The translucent resin 21 is made of, for example, an epoxy-based translucent resin, except for the external terminal 14 of the lead frame 11, the optical element 15, the optical transmission IC 16, the die pad portion 12 of the lead frame 11, and the inner lead. The portion 13 is sealed. In addition, a concave portion 22 having a shape corresponding to one end of the sleeve 31, that is, the bottom shape, is formed in a portion of the translucent resin 21 facing the optical element 15. The recess 22 is formed so that its central axis coincides with the light emission center of the optical element 15.

  The sleeve 31 is made of a translucent resin such as acrylic or polycarbonate, and is protected by a ferrule 41 as shown by a broken line so that an optical fiber 42 having a core at the center can be inserted. In the present embodiment, the sleeve 31 has a truncated cone shape with a top portion cut off, and has a bottomed cylindrical structure having a bottom. A convex lens 32 protruding in the top surface direction is formed integrally with the sleeve 31 at the center of the bottom surface of the sleeve 31, and the optical axis of the lens 32, the central axis of the sleeve 31, and the center of the optical fiber 42 are formed. It coincides with the axis. That is, the light emission center of the optical element 15 coincides with the central axis of the optical fiber 42. The bottom of the sleeve 31 is fixed by being fitted into the recess 22 of the translucent resin 21. That is, one end of the sleeve 31 is fixed in the translucent resin 21 and fixed.

  In order to make it difficult to remove the sleeve 31 from the concave portion 22 of the translucent resin 21, a convex portion is provided on one of the concave portion 22 and the bottom side surface of the sleeve 31, and a concave portion is provided on the other side so that the concave and convex portions are engaged. But it doesn't matter.

  The optical transmission device having the above structure is manufactured as follows. First, the optical element 15 and the optical transmission IC 16 are fixed to a predetermined position of the die pad part 12 of the lead frame 11 with a conductive material, and the optical element 15 and the optical transmission IC 16 and the inner lead part 13 of the lead frame 11 are connected to the Au wire 18. To make electrical connections.

  Next, the optical element 15, the optical transmission IC 16, the die pad portion 12 of the lead frame 11, except for the external terminal 14 of the lead frame 11 with a translucent resin 21 using a mold divided into an upper mold and a lower mold, The inner lead portion 13 is sealed, and the sleeve 31 is fixed to the translucent resin 21 by embedding one end portion thereof. For example, by aligning the reference position of the lead frame 11 with the reference position of the lower mold, the lead frame 11 is fixed to the lower mold, and similarly, the sleeve 31 is fixed to the insertion hole of the upper mold, and the upper mold and the lower mold are mounted. After the matching, an uncured epoxy-based translucent resin is injected into the mold. Thereafter, the sleeve 31 is embedded in the translucent resin 21 as shown in FIG. 1 by taking it out from the mold in a semi-cured state of the translucent resin and solidifying the translucent resin by heat treatment. The fixed optical transmission device 1 is completed.

  FIG. 2 is a cross-sectional view of an optical transmission module and an optical connector using the optical transmission apparatus of this embodiment.

  As illustrated in FIG. 2, the optical transmission module 100 includes the optical transmission device 1 illustrated in FIG. 1 and an envelope 101 that houses the optical transmission device 1, and transmits and receives optical signals to and from the optical transmission device 1. An optical connector 40 is attached.

  The envelope 101 is made of, for example, a resin having a light shielding property against transmission light, and includes a first receptacle 102 having a storage portion 102a and a second receptacle 103 serving as a lid of the storage portion 102a. . The optical transmission device 1 is housed in the housing portion 102a of the first receptacle 102 with the top of the sleeve 31 and the external terminal 14 protruding outward. Then, the lid is covered with the second receptacle 103, and the respective gaps of the optical transmission device 1, the first receptacle 102, and the second receptacle 103 are fixed with the light-shielding adhesive 104.

  The optical connector 40 includes a 50 μm-diameter core made of quartz glass at the center, an optical fiber 42 composed of a cladding layer disposed so as to cover the periphery thereof, a metal ferrule 41 that protects the optical fiber 42, A plug case 43 made of a light-shielding resin for facilitating protection of the fiber 42 and the like and easy attachment to and removal from the sleeve 31 is provided. When the optical fiber 42 of the optical connector 40 is inserted into the sleeve 31, the plug case 43 comes into contact with the outer surface of the sleeve 31 and firmly fixes the optical fiber 42 to the sleeve 31. By inserting the optical fiber 42 into the sleeve 31, the central axis of the optical fiber 42 coincides with the emission center of the optical element 15 of the transmission device 1.

  Note that a fastener (not shown) or the like may be provided on the sleeve 31 or the plug case 43 so as to further strengthen the mutual coupling. Further, the ferrule 41 may be made of ceramic or plastic other than metal.

  The optical transmission module 100 can transmit the optical signal of the optical element 15 controlled by the optical transmission IC 16 through the optical fiber 42 by supplying power and a transmission signal from the external terminal 14 of the optical transmission device 1. .

  In the light transmission module 100, the light transmission device 1 is covered with a light-shielding envelope 101, and a portion of the light-transmitting sleeve 31 protruding from the envelope 101 is a light-shielding plug case. 43, the optical signal of the optical element 15 is not affected by external light.

  According to the optical transmission apparatus of the present embodiment configured as described above, the concave portion 22 is formed in the portion of the translucent resin 21 facing the optical element 15 so that the central axis coincides with the light emission center of the optical element 15. By providing and fitting the sleeve 31 into the recess 22, the central axis of the sleeve 31 and the light emission center of the optical element 15 are aligned, and the sleeve 31 is fixed to the translucent resin 21. Therefore, the central axis of the sleeve 31 and the light emission center of the optical element 15 can be matched regardless of the clearance between the envelope 101 and the optical transmission device 1, the burr of the translucent resin 21 of the optical transmission device 1, and the like. it can. Therefore, as a result of measuring the optical coupling efficiency indicating the rate at which the optical signal from the optical element 15 is introduced into the optical fiber 42, the optical coupling efficiency between the optical element and the optical fiber having a small core diameter is 1% or less. Stabilize.

  Further, by inserting the optical fiber 42 into the recess 22, the distance between the optical element 15 and the optical fiber 42 can be made closer, and the optical coupling efficiency can be improved.

  Furthermore, since the convex lens 32 is provided at the center of the bottom surface of the sleeve 22 so that the optical signal from the optical element 15 is efficiently transmitted to the optical fiber 42, the optical coupling efficiency can be improved.

  An optical transmission apparatus according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view schematically showing the structure of the optical transmission apparatus. This embodiment is different in that the optical element of the first embodiment is replaced with a light receiving element, and the optical transmission IC is replaced with an optical transmission IC for receiving signal processing. Hereinafter, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted, and different components will be described.

  As shown in FIG. 3, in the optical transmission device 2, a light receiving element 55 is provided as an optical element in the die pad portion 12 of the lead frame 11, and an optical transmission IC 56 for processing received signals is provided in the vicinity of the light receiving element 55. ing. Contrary to the first embodiment, the signal light is emitted from the optical fiber 42, refracted by the convex lens 32, and guided to the light receiving element 55 through the translucent resin 21.

  According to the optical transmission apparatus of the present embodiment having the above structure, the measurement result of the optical coupling efficiency is 0.4% or less, and the optical coupling efficiency between the light receiving element and the optical fiber is the same as in the first embodiment. It is stable and the optical coupling efficiency can be improved.

  An optical transmission apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view schematically showing the structure of the optical transmission apparatus. The present embodiment is different from the first embodiment in that the sleeve has a structure penetrating from one end to the other end, and the lens is formed in the translucent resin portion. Hereinafter, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted, and different components will be described.

  As shown in FIG. 4, in the optical transmission device 3 of the present embodiment, the sleeve 61 has a structure that penetrates from one end to the other end. Further, a convex lens 62 formed by projecting the translucent resin on the other end side of the sleeve 61 is formed in the portion of the translucent resin 71 in the through hole at one end of the sleeve 61. The central axis of the convex lens 62 coincides with the light emission center of the sleeve 61 and the optical element 15.

  In the present embodiment, since the lens 62 is provided on the translucent resin 71, the sleeve 61 is not necessarily formed of a translucent material, and is not translucent, such as metal, ceramics, carbon, resin, You may form with glass or these composite materials.

  According to the optical transmission apparatus of the present embodiment having the above structure, the same effects as those of the first embodiment can be obtained, and the selection range of the forming material of the sleeve 61 is widened, so that the cost can be reduced. In addition, when the sleeve 61 is formed of a material other than the light transmitting material, the optical signal of the optical element is hardly affected by the external light, and transmission characteristics can be improved.

  As in the second embodiment, the optical element 15 may be replaced with a light receiving element, and the optical transmission IC 16 may be replaced with an optical transmission IC for processing received signals.

  An optical transmission apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view schematically showing the structure of the optical transmission apparatus. This embodiment is different from the first embodiment in that a lens is further added to form a two-group lens system. Hereinafter, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted, and different components will be described.

  As shown in FIG. 5, the optical transmission device 4 of the present embodiment is provided with a convex lens 83 in the sleeve 81 in the vicinity of the lens 32. This lens 83 has a double-sided convex shape, and is provided close to the lens 32 so as not to affect the insertion of the optical fiber 42 and is provided on a protrusion 87 provided on the inner wall of the sleeve 81, for example, an adhesive (not shown). It is fixed with. The optical axis of the lens 83 coincides with the central axis of the sleeve 81 and the light emission center of the optical element 15.

  In this optical transmission device 4, the optical signal of the optical element 15 controlled by the optical transmission IC 16 passes through the translucent resin 21, is refracted by the lens 32 and the lens 83, is introduced into the optical fiber 42, and is transmitted. The

  According to the optical transmission device of the present embodiment having the above structure, the same effect as that of the first embodiment can be obtained, and since the light is refracted by the two groups of lenses 32 and 83, the optical signal from the optical element 15 is accurately obtained. In addition, the light can be condensed on the end face of the optical fiber 42, and the optical coupling efficiency between the optical element 15 and the optical fiber 42 can be further improved.

  As in the second embodiment, the optical element 15 may be replaced with a light receiving element, and the optical transmission IC 16 may be replaced with an optical transmission IC for processing received signals.

  An optical transmission apparatus according to Embodiment 5 of the present invention will be described with reference to FIG. FIG. 6 is a cross-sectional view schematically showing the structure of the optical transmission apparatus. This embodiment differs from the first embodiment in that protrusions are added to alignment holes and sleeve parts for positioning in the lead frame. Hereinafter, the same reference numerals are given to the same components as those in the first embodiment, and the description thereof will be omitted, and different components will be described.

  As shown in FIG. 6, in the optical transmission device 5 of the present embodiment, an alignment hole 19 is formed in the die pad portion 12 of the lead frame 11. Further, a protrusion 97 having a thin tip is formed on the bottom surface of one end of the sleeve 91, and the tip of the protrusion 97 is inserted into the alignment hole 19 of the lead frame 11.

  The alignment hole 19 of the lead frame 11 and the protrusion 97 of the sleeve 91 are provided so that the light emission center of the optical element 15 coincides with the central axis of the sleeve 91, and the tip of the protrusion 97 is inserted into the alignment hole 19. By inserting and fixing with the translucent resin 21, the tip of the protrusion 97 is inserted into the alignment hole 19 so that the mutual positions of the lead frame 11 and the sleeve 91 do not move. It is fixed.

  The optical transmission device 5 having the above structure is manufactured as follows. First, similarly to the first embodiment, the optical element 15 and the optical transmission IC 16 are fixed to a predetermined position of the die pad portion 12 of the lead frame 11 with a conductive material, and the optical element 15, the optical transmission IC 16 and the inner portion of the lead frame 11 are fixed. The lead part 13 is electrically connected to each other by an Au wire 18.

  Next, the reference position of the lead frame 11 is aligned with the reference position of the lower mold, the lead frame 11 is fixed to the lower mold, the tip of the projection 97 of the sleeve 91 is inserted into the alignment hole 19 of the lead frame 11, and the upper Combine the mold and the lower mold. Thereafter, as in Example 1 above, an uncured epoxy-based translucent resin is injected into the mold, and the translucent resin is taken out of the mold in a semi-cured state, and heat-treated to transmit the light. The optical transmission device 5 as shown in FIG. 6 is completed by solidifying the conductive resin.

  According to the optical transmission device of the present embodiment having the above structure, in addition to the effects of the first embodiment, the sleeve 91 is attached to the lead frame 11 by inserting the protrusion 97 of the sleeve 91 into the alignment hole 19 of the lead frame 11. It is fixed. Therefore, when the sleeve 91 is fixed to the translucent resin 21, it is possible to reduce relative displacement between the optical element 15 and the sleeve 91 due to stress due to the flow of the translucent resin or stress during solidification. Become. Therefore, alignment between the light emission center of the optical element 15 and the central axis of the sleeve 91 can be performed more accurately, and variation in optical coupling efficiency can be further reduced.

  It should be noted that the protrusion 97 of the sleeve 91 may be such that a thin portion at the tip thereof passes through the alignment hole 19 of the lead frame 11 and extends to the outer surface of the translucent resin 21. For the purpose of making the interval between the sleeve 91 and the lead frame 11 constant, for example, the protrusion 97 of the sleeve 91 does not need to have a thin tip, and may be configured to contact the lead frame 11.

  As in the second embodiment, the optical element 15 may be replaced with a light receiving element, and the optical transmission IC 16 may be replaced with an optical transmission IC for processing received signals.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  For example, the protrusion of the fifth embodiment may be applied to the optical transmission devices of the second to fourth embodiments.

  In the third embodiment, an external lens may be disposed in one end of the sleeve. In that case, it is not always necessary to provide a lens in the translucent resin portion. In Example 4 described above, when the external lens is a high-performance lens, the lens provided in one end of the sleeve may be a flat plate without a convex portion.

  Moreover, although the sleeve showed the example of the frusto-conical external structure, even if the part which protrudes from translucent resin is a cylindrical structure, it does not interfere. In that case, needless to say, the shape of the plug case of the optical connector is changed according to the outer shape of the sleeve.

  In addition, although an example in which the translucent resin is stored in a light-shielding envelope has been shown, a part of the sleeve that is not involved in transmission of transmission light or reception light and the periphery of the translucent resin are made of a light-shielding material. It is okay to cover.

BRIEF DESCRIPTION OF THE DRAWINGS It shows typically the structure of the optical transmission apparatus which concerns on Example 1 of this invention, Fig.1 (a) is a top view, FIG.1 (b) is the cross section along the AA of Fig.1 (a). Figure. 1 is a schematic cross-sectional view of an optical transmission module and an optical connector that use an optical transmission device according to Embodiment 1 of the present invention. Sectional drawing which shows typically the structure of the optical transmission apparatus which concerns on Example 2 of this invention. Sectional drawing which shows typically the structure of the optical transmission apparatus which concerns on Example 3 of this invention. Sectional drawing which shows typically the structure of the optical transmission apparatus which concerns on Example 4 of this invention. Sectional drawing which shows typically the structure of the optical transmission apparatus which concerns on Example 5 of this invention.

Explanation of symbols

1, 2, 3, 4, 5 Optical transmission device 11 Lead frame 12 Die pad part 13 Inner lead part 14 External terminal 15, 55 Optical element 16, 56 Optical transmission IC
18 Wire 19 Alignment hole 21, 71 Translucent resin 22 Recess 31, 61, 81, 91 Sleeve 32, 62, 83 Lens 40 Optical connector 41 Ferrule 42 Optical fiber 43 Plug case 87, 97 Protrusion 100 Optical transmission module 101 Outside Enclosure 102 First receptacle 102a Storage portion 103 Second receptacle 104 Adhesive

Claims (5)

A substrate,
An optical element mounted on the surface of the substrate;
A translucent resin that seals part of the optical element and the substrate;
An optical transmission device comprising: a sleeve for embedding and fixing an optical fiber in an end portion embedded in and fixed to the translucent resin portion facing the optical element.   The optical transmission device according to claim 1, further comprising a lens inside one end of the sleeve.   The optical transmission device according to claim 1, further comprising: a lens integrally formed with the translucent resin in the translucent resin portion facing the optical element.   The recessed part is provided in the said translucent resin part facing the said optical element, The one end part of the said sleeve is fitted by the said recessed part, The Claim 1 characterized by the above-mentioned. Optical transmission device.   5. The optical transmission device according to claim 1, wherein a projection that contacts the substrate is provided at the one end of the sleeve.

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