JP2005309092A - Optical connector and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simply structured optical connector that makes a light beam inputted in one end to be outputted from the other end through a bent optical transmission line. <P>SOLUTION: In this optical connector, a light beam inputted in one end 408 is outputted from the other end 410 through a bent optical transmission line. This optical connector is equipped with a clad material part 402 composed of a transparent first material extending along the optical transmission line and with a core material part 602 composed of a transparent second material which is filled in at least one of the plurality of through holes 406 formed extendedly from one end to the other end in the clad material part. The plurality of through holes are continuously surrounded with the clad material part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention belongs to the technical field of optical communication, and particularly relates to an optical connector connected to a light emitting element, a light receiving element, an optical fiber, and other optical elements, and a method for manufacturing the optical connector.

  In this type of technical field, edge-emitting or surface-emitting light emitting elements are mainly used. Since the edge-emitting light emitting element emits light parallel to the mounting substrate, it is convenient to connect to an optical element such as an optical fiber provided on the mounting substrate. In this type of light emitting element, light is emitted from an end face formed after dicing from a wafer. Therefore, in order to provide a plurality of light emitting elements on the mounting substrate, as shown in FIG. 1, it is necessary to accurately adjust the pitch (for example, 250 μm) between the light emitting elements at the time of mounting. However, it is not easy to mount the light emitting element while taking into consideration dimensions important for device characteristics such as the pitch interval, and there is a risk of increasing the cost. In this type of light emitting device, light is emitted from the end face of the very thin active layer. Since light is emitted with a small aperture, there is a problem that the shape of the emitted light is greatly distorted. There is also a need to correct the distorted light beam with an optical system.

  On the other hand, in the surface-emitting light emitting device, as shown in FIG. 2, it is possible to adjust the light emission pitch interval in the manufacturing process before dicing from the wafer. For this reason, the mounting process of the light-emitting element becomes very simple as compared with the edge-emitting type. Furthermore, since the light emission aperture is large, the emitted light is not greatly distorted. For this reason, surface-emitting light-emitting elements are promising.

However, the surface-emitting light emitting element emits light in a direction perpendicular to the mounting substrate. Therefore, in order to connect to the optical element provided on the mounting substrate, the light transmission path is bent (from the direction perpendicular to the substrate to the parallel direction or vice versa), particularly when a thin and small product is manufactured. Bend). Conventional optical connectors that bend the optical transmission path are disclosed in, for example, Patent Documents 1, 2, 3, and 4.
JP-A-62-35304 JP-A-5-88029 International Publication No. 00/08505 Pamphlet US Pat. No. 6,137,929

  In the inventions described in Patent Documents 1, 2, and 3, as shown in FIG. 3, an inclined mirror 306 is provided between a light emitting element 302 provided on the mounting substrate 301 and an optical fiber 304 parallel to the mounting substrate 301. And the lens 308 are provided to bend the light transmission path. However, if such an optical system is configured, the number of components to be mounted increases, the structure becomes complicated, and it is necessary to accurately align all of these components, which may increase the product cost. Furthermore, the inclined mirror 306 itself needs to be a high-performance mirror having a mirror surface with high flatness and low surface roughness. This may also affect the cost increase. Such problems can become increasingly serious as parts are miniaturized.

  On the other hand, in the invention described in Patent Document 4, the optical fiber 304 itself is bent and attached to the light emitting element 302. This method does not require alignment of a large number of parts or a high-performance tilt mirror. However, it is generally difficult to perform an assembly process in which the optical fiber is bent and fixed with high accuracy. Furthermore, considering the mechanical strength and optical loss of the optical fiber, a bending radius larger than 20 mm is required, which is too large for current and future small product applications. For such product applications, it is desirable to achieve a bend radius of 1 cm or less.

  The present invention is intended to address at least one of the above problems, and the problem is that an optical connector that outputs light input to one end from the other end through a bent optical transmission line is simplified. It is providing the optical connector which has a structure, and providing the manufacturing method for manufacturing such an optical connector simply.

According to one aspect of the invention,
In the optical connector that outputs light input from one end through the bent optical transmission path from the other end,
A clad material portion made of a transparent first material extending along the optical transmission path;
A core material portion made of a transparent second material filled in at least one of a plurality of through-holes extending from the one end to the other end formed in the cladding material portion, An optical connector characterized in that it is continuously surrounded by a clad material part is obtained.

  According to the present invention, an optical connector having a simple configuration can be obtained, and such an optical connector can be manufactured at low cost.

  FIG. 4 is a diagram showing a part of the manufacturing process of the optical connector according to the embodiment of the present invention. The AA line sectional view and BB line sectional view of the member shown on the right side in the figure are shown on the left side. First, a clad portion 402 having a shape as shown on the right side is formed. The clad portion 402 has two alignment through holes 404 and four core through holes 406. These six through holes 404 and 406 are arranged in parallel to each other and reach from the one end 408 to the other end 410 of the clad member 402. As shown in the cross-sectional view along the line AA and the cross-section along the line BB on the left side of the drawing, the alignment through hole 404 generally has a larger diameter than the core through hole 406. The clad member 402 is made of a transparent first material, and is made of, for example, plastic, glass (particularly, low-melting glass), quartz, etc., preferably made of plastic, and more preferably thermoplastic resin (polyolefin resin). . The reason for using such a transparent material is that light transmission is performed in a core material described later, but the cladding material 402 is also involved in the light transmission.

  The number and positional relationship of the alignment through-holes 406 and the core through-holes 406 can be appropriately changed depending on the product application and standard of the optical connector to be created. For example, the number of core through holes 406 may be eight. In the present embodiment, an optical connector that is compatible with a 4-channel MT (mechanically transferable) connector conforming to the JIS standard is intended. Of course, it is possible to apply the present invention to other connectors in which the concave portion and the convex portion are coupled.

  As an example of the dimensions, the alignment through hole 404 has a diameter of 700 μm, and the core through hole 406 has a diameter of 50 μm. The thickness of the clad member 402 is 2 mm, and the length from one end 408 to the other end 410 is 17 mm. The refractive index of the clad member 402 is 1.50. The pitch interval between the core through holes 406 is 250 μm, and the pitch interval between the alignment through holes 404 and the core through holes 406 is 1925 μm.

  Such a cladding portion 402 can be formed by injection molding using a mold as shown in FIG. 5, for example. In FIG. 5, it should be noted that the upper and bottom mold blocks are not drawn for simplicity. The clad member is molded by pouring the first material into a space sealed with such a mold. The columnar element 504 is a mold for forming the alignment through hole 404, and its tip is supported by the pin catcher 514 when sealed. The columnar element 506 is a mold for forming the core through-hole 406, and its tip is supported by the pin catcher 516 when sealed.

  The clad portion 402 can be formed not only by injection molding but also by, for example, press molding, mechanical cutting, laser ablation, sand blasting, plasma processing, or the like. However, injection molding is desirable from the viewpoint of simple creation.

  FIG. 6 is a diagram showing the next stage of the manufacturing process shown in FIG. The AA line sectional view and BB line sectional view of the member shown on the right side in the figure are shown on the left side. The core through hole 404 is filled with a transparent second material (core material) 602. The alignment through hole 404 is not filled with such a material and remains a through hole. The second material 602 is a material having a refractive index higher than that of the first material. For example, plastic, glass (especially, low melting point glass) or the like can be used. In particular, a thermosetting resin or an ultraviolet curable resin (acrylate resin, alicyclic epoxy resin, etc.) is desirable. In this embodiment, an ultraviolet curable resin having a refractive index of 1.55 is used for the second material 602. Regarding the step of filling the core through-hole 406 with the second material 602, the material can be poured into the through-hole and / or sucked with a pump.

  FIG. 7 is a diagram showing the next stage of the manufacturing process shown in FIG. A sectional view of the member shown on the right side in the figure is shown on the left side. In this step, the clad portion 402 in which the core material 602 is filled in the through hole is mechanically pressed and bent under the condition of reducing the elastic modulus thereof. The wavy line in the figure represents the alignment through hole 406. In this embodiment, the clad portion 402 is bent to have a bending radius of 10 mm by being pressed with a metal block (not shown) heated to 140 degrees Celsius. Thereby, the optical transmission path is bent. The condition for lowering the elastic modulus is to heat the material to about the softening temperature. In this embodiment, the melting point of the first material constituting the cladding material 402 needs to be higher than the melting point of the second material constituting the core material 602.

  In this embodiment, the core material 602 is filled before the cladding portion 402 is bent. However, the order of these steps can be reversed. That is, it is possible to bend the clad portion 402 before filling the core through hole 406 of the clad material 402 with the core material, and then fill the core material 602 into the core through hole 406 of the clad portion. However, from the viewpoint of simply injecting the core material 602, it is desirable to inject the core material 602 before bending the clad portion 402 as in this embodiment.

  FIG. 8 is a view showing a support structure used in an optical connector according to an embodiment of the present invention. In general, the support structure 802 is an element that supports the cladding portion 402 and facilitates connection to a mounting substrate (not shown) or an optical fiber. The support structure 802 has a curved surface portion 812 that is curved in accordance with the bent shape of the clad member 402. The clad portion 402 is provided on the curved surface portion 812. In this case, one end 408 of the clad portion 402 fits with one end 808 of the support structure 802 and the other end 410 of the clad portion 402 fits with the other end 810 of the support structure 802. A lens 806 is formed on the support structure 802 in accordance with the position of the core material 602 at one end and the other ends 408 and 410 of the clad portion 402. An alignment through hole 804 is also formed in accordance with the position of the through hole 404 at one end and the other ends 408 and 410 of the clad portion 402. The support structure 802 is provided with an adjustment unit 807 for maintaining a distance from other connected elements such as an optical fiber. The adjustment unit 807 prevents the lens 806 from contacting other elements by maintaining a constant interval. The support structure 802 can be made of the same material, or the lens 806 can be made of a different material. In this embodiment, the support structures 802 are all formed of the same material, and the material is the same first material as the cladding material 402.

  The support structure 802 can be made by injection molding, press molding, machine cutting, laser ablation, sand blasting, plasma processing, or the like. However, from the viewpoint of simple production, injection molding is desirable, and further, it is desirable to form the lens together by injection molding.

  The shape of the clad member 402 and the support structure 802 as shown in FIG. 7 may be such that one end and the other end are oriented in a desired direction from the viewpoint of bending the optical transmission path. The curved surface 812 may not be a circular arc. However, from the viewpoint of simplification of part structure and ease of manufacturing process, the shape of the cladding 402 and the curved surface 812 should be a quadrant and have the same shape on one end side and the other end side. Is desirable.

  FIG. 9 is a diagram showing a usage pattern of the optical connector according to one embodiment of the present invention. In this aspect, the optical connector according to the embodiment of the present invention is used to connect the surface emitting light emitting element 912 provided on the mounting substrate 901 and the optical fiber 902. The optical connector includes a support structure 803 and a clad portion 402 provided on the support structure 803. A core material 602 is filled in the core through-hole in the clad portion 402. An MT connector 903 is attached to the end of the optical fiber 902, and the MT connector 903 is aligned with other elements by guide pins 904. The guide pin 904 is inserted into the alignment through hole 404 on the clad portion 402 side. A guide pin 904 ′ is also provided on the mounting substrate 901 side, and this guide pin 904 ′ is also inserted into the alignment through hole 404 on the cladding portion 402 side.

  Note that the alignment through hole 404 of the clad portion 402 does not need to penetrate the entire length direction of the clad portion 402 from the viewpoint of receiving the guide pins 904 and 904 ′. It suffices if a hole longer than the length of the guide pin is formed. However, from the viewpoint of injection molding, it is desirable to form a through hole from one end to the other end as in this embodiment. In order to form an alignment through hole having a shallow depth, for example, the columnar mold 504 shown in FIG. 5 needs to be shortened. However, if the columnar mold 504 is short, the tip of the columnar mold 504 does not reach the pin catcher 514, so that the columnar mold 504 is in a cantilever state and may be damaged by the flow of liquid material during molding. .

  FIG. 10 is a diagram showing another usage pattern of the optical connector according to one embodiment of the present invention. Also in this aspect, the optical connector according to the embodiment of the present invention is used to connect the surface light emitting element 912 provided on the mounting substrate 901 and the optical fiber 902. The optical connector includes a support structure 802 as described in FIG. 8 and a clad portion 402 provided on the support structure 802. In this aspect, the lens 806 is interposed between the optical fiber 902 and the clad portion 402, and between the clad 402 and the light emitting element 912, thereby further collecting light.

  In the above usage pattern, an example of an optical connector for connecting between a light emitting element and an optical fiber is shown. However, the optical connector according to the present invention is a light between a light emitting element, a light receiving element, an optical fiber, and any other optical element. It can be used for bonding.

  As described above, according to the optical connector according to the embodiment of the present invention, the transmission path can be bent with a small bending radius that is difficult to be bent by the optical fiber. According to the optical connector according to the embodiment of the present invention, since the number of components is small (because there is only one optical connector), complicated alignment is not necessary, and a high-performance tilting mirror is not necessary. The core material 602 filled in the plurality of through-holes 406 is continuously surrounded by the clad portion 402 continuously. The clad portion 402 is integrally formed of one kind of material. Therefore, a phenomenon such as crosstalk in which light propagating in one core material leaks into another core material is extremely unlikely to occur. The support structure 802 can be easily formed by injection molding or the like. By providing the support member 802 with the clad member 402, an optical connector having excellent strength can be formed. Furthermore, since the lens 806 can be formed integrally with the support structure 802, it is possible to appropriately collect the propagating light while increasing the strength of the optical connector.

  Hereinafter, the means taught by the present invention will be listed as an example.

(Appendix 1)
In the optical connector that outputs light input from one end through the bent optical transmission path from the other end,
A clad material portion made of a transparent first material extending along the optical transmission path;
A core material portion made of a transparent second material filled in at least one of a plurality of through-holes extending from the one end to the other end formed in the cladding material portion, An optical connector characterized by being continuously surrounded by a clad material part.

(Appendix 2)
The optical connector according to appendix 1, wherein a positioning pin is inserted into at least one of the plurality of through holes.

(Appendix 3)
Furthermore,
A curved surface-shaped portion along the cladding member;
The optical connector according to claim 1, further comprising: a support structure having a lens provided in accordance with the core material portion at the one end or the other end.

(Appendix 4)
The optical connector according to appendix 3, wherein the curved surface portion and the lens are made of the same transparent material.

(Appendix 5)
The optical connector according to appendix 1, wherein the first or second material is plastic.

(Appendix 6)
The optical connector according to appendix 5, wherein the first material is made of a thermoplastic resin.

(Appendix 7)
The optical connector according to appendix 5, wherein the second material is made of an ultraviolet curable resin.

(Appendix 8)
The optical connector according to appendix 1, wherein the optical connector forms an MT connector.

(Appendix 9)
Forming a cladding material portion made of a transparent first material having a plurality of through holes extending in parallel;
Filling at least one of the plurality of through holes formed in the cladding material portion with a core material made of a transparent second material;
And a step of mechanically bending the shape of the clad member and the core material. A method of manufacturing an optical connector that outputs light input to one end from the other end through a bent optical transmission line.

It is a figure which shows an end surface light emission type light emitting element. It is a figure which shows a surface emitting type light emitting element. It is a figure which shows the conventional optical connector. It is a figure which shows a part of manufacturing process of the optical connector by one Example of this invention. It is a figure which shows the conceptual diagram of the metal mold | die used for the manufacturing process of FIG. It is a figure which shows a part of manufacturing process of the optical connector by one Example of this invention. It is a figure which shows a part of manufacturing process of the optical connector by one Example of this invention. It is a figure which shows the support structure used for the optical connector by one Example of this invention. It is a figure which shows the usage condition of the optical connector by one Example of this invention. It is a figure which shows another usage pattern of the optical connector by one Example of this invention.

Explanation of symbols

402 Cladding part 404 Alignment through hole 406 Core through hole 408 One end of clad part 410 Other end of clad part 504 Mold for alignment through hole 506 Mold for core through hole 514, 516 Pin catcher 602 Core material 802, 803 Support structure 804 Positioning through-hole 806 Lens 812 Curved surface portion 901 Mounting substrate 902 Optical fiber 903 MT connector 904, 904 'Guide pin 912 Light emitting element

Claims (5)

In the optical connector that outputs light input from one end through the bent optical transmission path from the other end,
A clad material portion made of a transparent first material extending along the optical transmission path;
A core material portion made of a transparent second material filled in at least one of a plurality of through-holes extending from the one end to the other end formed in the cladding material portion, An optical connector characterized by being continuously surrounded by a clad material part. The optical connector according to claim 1, wherein a positioning pin is inserted into at least one of the plurality of through holes. Furthermore,
A curved surface-shaped portion along the cladding member;
The optical connector according to claim 1, further comprising: a support structure portion having a lens provided in accordance with the core material portion at the one end or the other end. The optical connector according to claim 2, wherein the curved shape portion and the lens are made of the same transparent material. Forming a cladding material portion made of a transparent first material having a plurality of through-holes extending in parallel;
Filling at least one of the plurality of through holes formed in the cladding material portion with a core material made of a transparent second material;
And a step of mechanically bending the shape of the clad member and the core material. A method of manufacturing an optical connector that outputs light input to one end from the other end through a bent optical transmission line.

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