JP2008015302A - Optical substrate and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical substrate and a manufacturing method thereof capable of suppressing a manufacturing cost low while enhancing manufacturing efficiency of the optical substrate with respect to the method of manufacturing the optical substrate in which a linear core is disposed in a substrate main body having a refractive index lower than that of the core. <P>SOLUTION: The method of manufacturing the optical substrate includes: an optical waveguide formation step of arranging a linear core 5 in a substrate body 3 having a refractive index lower than that of the core 5 and protruding ends 5a, 5b in the longitudinal direction of the core 5 from the substrate body 3 to the outside; and an end surface molding process of heating and melting end surfaces 5c, 5d of the core 5 protruded from the substrate body 3 with heating means 33, 35 and molding the end surfaces 5c, 5d into an arbitrary shape. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical substrate and a method for manufacturing the same.

  The LSI clock frequency of electronic computers tends to increase more and more, and now the one of the order of 1 GHz has appeared. As a result, if the electrical transmission in the conventional board or system is used as it is, the speed is limited, which is a cause of hindering the system performance. Such speed limitations were caused by the effects of high frequency attenuation due to electrical transmission, impedance mismatch, crosstalk, and ground noise. Furthermore, when the performance of terabit / second is required, in the case of electrical transmission, there is a problem that the allowable transmission distance in the board is shortened along with the increase in speed due to high-frequency attenuation due to dielectric loss and skin effect.

In recent years, in order to solve such a problem, a part of the electrical wiring made of copper on the printed board is replaced with an optical fiber or an optical waveguide, and an optical signal is used instead of an electrical signal. This optical transmission has the advantage that the above-mentioned adverse effects such as impedance mismatching can be ignored and the allowable transmission distance does not depend on the transmission speed.
An optical substrate including such an optical waveguide is configured by embedding a linear core that normally transmits an optical signal in a clad having a refractive index lower than that of the core, as shown in Patent Document 1, for example. Optical transmission is performed by a transmission / reception optical device such as a laser diode or a photodiode.

Conventionally, when manufacturing an optical substrate having such a configuration, as shown in Non-Patent Document 1, for example, the optical substrate is cut by dicing cut or laser cut so that the end surface in the longitudinal direction of the core is a flat surface. is doing.
Also, when the optical substrate is cut by dicing cut or laser cut, the end surface of the core needs to be mirrored so that the optical signal is not scattered at the end surface of the core. Has been given.
JP 2004226694 A “Development of new polyimide and technology for high functionality for next-generation electronics and electronic materials”, 1st edition, Technical Information Association, October 30, 2003, p. 209-221

In the conventional method for manufacturing an optical substrate, since the optical substrate including the clad is cut by dicing cut or laser cut, a lot of time is required for cutting, and the manufacturing efficiency of the optical substrate is lowered. For example, when dicing cut is performed, the cutting speed is as slow as about 1 mm / sec, and a lot of cutting time is required for cutting.
In addition, when the optical substrate is cut by laser cutting, it is necessary to configure the core and cladding of the optical substrate with a material capable of absorbing the energy of the laser, that is, the materials constituting the core and cladding of the optical substrate are limited. Therefore, there is a problem that versatility is low.
Furthermore, since it is necessary to perform polishing in addition to the above cut, there is a problem that the number of manufacturing steps of the optical substrate increases and the manufacturing cost of the optical substrate increases.

  The present invention has been made in view of the above-described circumstances, and can reduce the manufacturing cost while improving the manufacturing efficiency, and is manufactured by using a highly versatile manufacturing method of an optical substrate. An object is to provide an optical substrate.

In order to solve the above problems, the present invention proposes the following means.
According to the first aspect of the present invention, an optical waveguide is formed in which a linear core is disposed inside a substrate body having a refractive index lower than that of the core, and an end portion in the longitudinal direction of the core protrudes outward from the substrate body. Proposing a method of manufacturing an optical substrate, comprising: a step; and an end surface forming step of heating and melting the end surface of the core protruding from the substrate body by a heating means to form an arbitrary shape. .

According to the method for manufacturing an optical substrate according to the present invention, an optical substrate in which an optical waveguide for propagating an optical signal is produced by a linear core and a substrate body disposed around the core.
In the end face forming step, the end face of the core protruding from the substrate body is melted by the heating means and formed into an arbitrary shape, so that the end face can be easily and quickly formed into an arbitrary shape. It becomes possible to make the end face into a mirror state without polishing.

In this end face forming step, the end face of the core is melted and formed into an arbitrary shape by a simple heating means, so there is no need to limit the constituent material of the core as in the conventional laser cut.
In addition, since the end face of the protruding core is melted and formed into an arbitrary shape, when the optical substrate includes a plurality of cores, the end face of the plurality of cores can be simultaneously formed into the same arbitrary shape by heating. And it becomes possible to shape | mold into a mutually different shape by heating the end surface of a several core separately.

  The invention according to claim 2 is the method of manufacturing an optical substrate according to claim 1, wherein the heating means is a hot plate having a flat surface, and the heated hot plate is heated in the end face forming step. A method of manufacturing an optical substrate is proposed in which a flat surface is pressed against an end surface of the core and the end surface of the core is formed into a flat surface.

In the method of manufacturing an optical substrate according to the present invention, the end surface of the core that is in contact with the flat surface of the hot plate is melted only by pressing the heated hot plate against the end surface of the core. Will be. Then, by setting the flat surface of the hot plate in a mirror surface state, the end surface of the core can be formed into a flat surface and simultaneously in the mirror surface state.
In addition, when the flat surface of the hot plate is inclined with respect to the longitudinal direction of the core and pressed against the end surface of the core in the end surface molding process, the end surface of the core molded into the flat surface is inclined with respect to the longitudinal direction of the core. Mirror surface. The angle of the mirror surface can be easily and accurately set only by changing the angle of the flat surface of the hot plate with respect to the longitudinal direction of the core.

Furthermore, by simultaneously pressing the flat surfaces of the same hot plate against the end surfaces of the plurality of cores, the end surfaces of the plurality of cores can be simultaneously formed into flat surfaces. When the same hot plate is inclined and simultaneously pressed against the end faces of the plurality of cores, the angles of the mirror surfaces of the plurality of cores can be easily matched.
Further, when the hot plate is individually pressed against a plurality of cores, the end surfaces of the cores can be set at different angles.
And in the optical substrate provided with this mirror surface, the light can be incident on the mirror surface through the substrate body from the outside, and this light can be reflected on the mirror surface and introduced into the core. Further, in this optical substrate, the light propagating in the core can be reflected on the mirror surface and emitted to the outside of the optical substrate.

  Furthermore, the invention according to claim 3 is the method of manufacturing an optical substrate according to claim 1, wherein, in the end face forming step, the end face of the core is melted by the heating means and formed into a spherical shape. An optical substrate manufacturing method is proposed, characterized in that the end face is formed into a lens shape.

In the method for manufacturing an optical substrate according to the present invention, since the end surface of the core protrudes, the end surface of the core can be easily formed into a spherical shape by forming a lens shape.
In the optical substrate having this lens shape, since the optical signal entering and exiting the end portion of the core can be condensed on the end surface of the core having the lens shape, a laser diode or a photo diode connected to the end portion of the core is used. An optical signal can be efficiently transmitted between a transmission / reception optical device including a diode, an optical fiber, and the like.

According to a fourth aspect of the present invention, there is provided a mirror surface manufactured by the optical substrate manufacturing method according to the second aspect, wherein the end surface of the core formed into a flat surface is inclined with respect to the longitudinal direction of the core. An optical substrate characterized by the above is proposed.
When the optical substrate according to the present invention is manufactured, the flat surface of the hot plate may be pressed against the end surface of the core in a state where the flat surface is inclined with respect to the longitudinal direction of the core. According to this optical substrate, an optical signal transmitted between a transmission / reception optical device and an optical fiber can be reflected on the mirror surface and propagated in and out of the core.

Further, the invention according to claim 5 is manufactured by the method for manufacturing an optical substrate according to claim 3,
An optical substrate is proposed in which the end face of the core has a lens shape.
According to the optical substrate of the present invention, since the optical signal entering and exiting the end portion of the core can be collected on the end surface of the core formed in the lens shape, the transmission / reception optical device connected to the end portion of the core, An optical signal can be efficiently transmitted between optical fibers and the like.

According to the first aspect of the present invention, the end surface of the core can be easily and quickly formed into an arbitrary shape, and the end surfaces of the plurality of cores can be simultaneously formed even if the optical substrate includes a plurality of cores. Therefore, the manufacturing efficiency of the optical substrate can be improved.
In addition, since the end face forming step can be performed without limiting the constituent material of the core, it is possible to provide a highly versatile optical substrate manufacturing method that is not affected by the constituent material of the core.
Furthermore, since it becomes possible to make the end surface of a core into a mirror surface state without performing a grinding | polishing process separately, the manufacturing process number of an optical board | substrate can be reduced and the manufacturing cost of an optical board | substrate can be restrained low.

According to the invention of claim 2, the end surface of the core can be easily formed into a flat surface simply by pressing the hot plate against the end surface of the core.
Further, since the mirror surface with the angle set accurately can be easily formed, the reliability of the optical substrate provided with the mirror surface can be improved and the optical substrate can be provided at low cost.
In addition, by simultaneously pressing the flat surface of the same hot plate against the end surfaces of a plurality of cores, the end surfaces of the plurality of cores can be formed into a flat surface at the same time. Cost can be further reduced.
Further, when the same hot plate is inclined and simultaneously pressed against the end faces of the plurality of cores, the angles of the mirror surfaces of the plurality of cores can be easily matched.
Further, when the hot plate is individually pressed against the plurality of cores, the end surfaces of the cores can be easily set at different angles.

Further, according to the inventions according to claim 3 and claim 5, since the optical signal can be efficiently transmitted between the transmission / reception optical device and the optical fiber connected to the end of the core, the transmission / reception optical device And reliability of connection with optical fibers and the like can be improved.
Moreover, according to the invention which concerns on Claim 3, the optical board | substrate provided with the condensing function by a lens shape can be manufactured easily, and the manufacturing efficiency of this optical board | substrate can be improved.

  Furthermore, according to the invention which concerns on Claim 4, the highly functional optical board which can reflect the optical signal transmitted between transmission / reception optical devices and an optical fiber in a mirror surface, and can propagate in and out of a core is provided. can do.

Hereinafter, with reference to FIGS. 1-4, the optical board | substrate which concerns on 1st Embodiment of this invention, and its manufacturing method are demonstrated. The optical substrate according to this embodiment is configured by providing a linear core having a refractive index higher than that of the substrate body inside the substantially plate-shaped substrate body. Both of the substrate body and the core are formed of an optical material having optical transparency.
When manufacturing this optical substrate, as shown in FIG. 1, a linear core 5 is manufactured in advance. Here, when manufacturing the core 5, first, as shown to Fig.1 (a), the type | mold 20 which has the recessed part 20B recessed from the flat surface 20A is prepared. In this recess 20B, a bottom surface 20C made of a semicircular cylindrical surface formed with a radius having the same dimension as the radius of the core 5 is formed, and the dimension between the lowermost portion of the bottom surface 20C and the flat surface 20A is as follows. The size is the same as the diameter of the core 5 or slightly larger than the diameter of the core 5. Then, as shown in FIG. 1B, the core 5 having a substantially circular cross section can be formed by raising, filling, and curing the core material in the recess 20B.

2B, the linear core 5 is disposed inside the substrate body 3 having a refractive index lower than that of the core 5, and one end portion (end portion) 5a in the longitudinal direction of the core 5 and others. The end portion (end portion) 5b is projected outward from the substrate body 3 (optical waveguide forming step).
When performing this process, for example, a hollow mold 23 shown in FIG. The mold 23 is used for molding the substrate body 3, and the inner wall surface thereof forms the outer shape of the substrate body 3. The mold 23 is formed with a plurality of insertion holes 25 and 25 which are communicated outwardly from the internal space and through which the end portions 5a and 5b of the core 5 are inserted. The core 5 is closed while the end portions 5a and 5b of the core 5 are inserted. Further, in the mold 23, the inner wall surface on which the insertion holes 25, 25 through which the one end portion 5 a and the other end portion 5 b of the core 5 are inserted is inclined inner surfaces 27, which are inclined with respect to the insertion direction of the core 5. 27.
As a material constituting the mold 23, a material having good releasability with respect to the constituent material of the substrate body 3 is preferable. For example, stainless steel, ceramic, silicon, nickel, various resins, and quartz are selectively used. That's fine.

In the optical waveguide forming process, the core 5 is disposed in the mold 23 and the end portions 5a and 5b of the core 5 are inserted into the insertion holes 25 and 25. Fill with material and cure. The constituent material may be injected from an injection hole 29 formed in the mold 23. Further, by forming the air discharge hole 31 separately from the injection hole 29 in the mold 23, the above-mentioned constituent materials can be injected smoothly.
Finally, by removing the substrate body 3 and the core 5 from the mold 23, an optical signal is propagated by the linear core 5 and the substrate body 3 disposed around the core as shown in FIG. 2B. An optical waveguide is formed, and the optical waveguide formation process is completed.

In the substrate body 3 formed in this step, the side surfaces 3a and 3b from which the end portions 5a and 5b of the core 5 protrude are inclined planes 3a and 3b that match the shapes of the inclined inner surfaces 27 and 27, respectively.
In addition, this board | substrate body 3 can be set to arbitrary thickness dimensions, and may be a thick plate-like board | substrate which does not have flexibility even if it is a thin film-like film which has flexibility. . The substrate body 3 can be set to a shape having an arbitrary appearance. That is, the substrate body 3 may be formed in a rectangular shape, a circular shape, a diamond shape, or a step shape when viewed from above.

Next, as shown in FIGS. 3 and 4, the flat surfaces 33 a of the heated hot plates (heating means) 33 and 35 are formed on the end surfaces 5 c and 5 d of the end portions 5 a and 5 b of the core 5 protruding from the substrate body 3. Each of the end surfaces 5c and 5d of the core 5 is melted by the heat of the hot plates 33 and 35 and formed into a flat surface (end surface forming step), whereby the manufacture of the optical substrate 1 is completed.
In addition, the heating temperature of the hot plates 33 and 35 in this step is set to a temperature that is equal to or higher than the glass transition temperature (Tg) of the core 5 and does not carbonize the core 5. Therefore, the melting of the core 5 described above includes not only that the end surfaces 5c and 5d of the core 5 become liquid, but also that the end surfaces 5c and 5d of the core 5 are softened. Moreover, when performing this process, you may cut | disconnect each edge part 5a, 5b of the core 5 by dicing etc. previously, and may adjust the protrusion length of each edge part 5a, 5b of the core 5. FIG.

Moreover, the flat surfaces 33a and 35a of the hot plates 33 and 35 are in a mirror surface state, and the end surfaces 5c and 5d of the core 5 formed into a flat surface thereby are also in a mirror surface state. Further, in this step, the flat surfaces 33 a and 35 a of the hot plates 33 and 35 are parallel to the inclined planes 3 a and 3 b of the substrate body 3, that is, the flat surfaces 33 a and 35 a of the hot plates 33 and 35 are the core 5. It is performed in a state inclined with respect to the longitudinal direction.
As described above, the end surfaces 5c and 5d of the core 5 formed into a flat surface can be mirror surfaces 5c and 5d inclined with respect to the longitudinal direction of the core 5.

In the optical substrate 1 manufactured as described above, an optical signal transmitted between a transmission / reception optical device such as a laser diode or a photodiode or an optical fiber is transmitted from the outside via the substrate body 3 to the mirror surface 5c, By being incident toward 5d, this optical signal can be reflected on the mirror surfaces 5c and 5d and introduced into the core 5. In the optical substrate 1, the optical signal propagating in the core 5 can be reflected by the mirror surfaces 5 c and 5 d and emitted to the outside of the optical substrate 1.
That is, it is possible to provide a highly functional optical substrate 1 that can reflect an optical signal transmitted between a transmission / reception optical device and an optical fiber on the mirror surfaces 5c and 5d and propagate the optical signal in and out of the core 5.

  For the core material constituting the core 5 and the clad material constituting the substrate body 3, a light-transmitting optical material having an adjusted refractive index may be used. For example, quartz material, organic-inorganic composite material, organic material Materials (polyimide, epoxy, silicon, acrylic, urethane, carbonate, and modified compounds thereof) can be used. The core material and the clad material are desirably heat-cured or ultraviolet-cured.

Here, examples of the ultraviolet curable material include a material composed of a photopolymerizable oligomer (UV prepolymer), a photopolymerizable monomer (UV monomer), and a photopolymerization initiator. As the UV prepolymer, for example, epoxy acrylate, aliphatic cyclic epoxy resin, bisphenol type epoxy resin, brominated epoxy resin, urethane acrylate, polyester acrylate, polyether acrylate, polyol acrylate, alkyd acrylate and the like can be used. As the UV monomer, for example, an acrylic monomer such as a monofunctional acrylate, a bifunctional acrylate, a trifunctional acrylate, or a tetrafunctional acrylate can be used. Examples of the photopolymerization initiator include aromatic diazonium salts such as benzoin, acetophenone, peroxide, thioxanthone, p-methoxybenzenediazonium hexafluorophosphate, and aromatic sulfonium salts such as triphenylsulfonium hexafluorophosphate. It is done.
The core material and the clad material can be composed of an ultraviolet curable resin having these compositions as constituent elements.

  By the way, the light transmission loss in the optical waveguide constituted by the core 5 and the substrate body 3 is influenced by factors specific to the substance such as the harmonic loss of infrared vibration absorption and scattering loss due to Rayleigh scattering due to density / concentration fluctuation. Among these, in order to suppress fluctuations in the solid due to thermal motion, the above resin that is three-dimensionally cured by ultraviolet rays or the like is preferable to the linear polymer. In addition, the refractive index of the polymer optical waveguide that is cured by ultraviolet rays can be freely controlled by changing the molecular structure and composition. Thus, the core material and the clad material forming the optical waveguide can be set so as to have a refractive index difference suitable for the wavelength of optical transmission.

As a further specific example of the ultraviolet curable resin used for the core material and the clad material, there is a material in which the following are mixed thoroughly.
Phenol novolac type epoxy acrylate molecular weight 5000; manufactured by Shin-Nakamura Chemical Co., Ltd. 16.25 parts by weight Photopolymerizable monomer; Dipentaerythritol pentaacrylate ... 13.75 parts by weight Photopolymerization initiator; 2-benzyl 2-Dimethylamino-1- (4-morpholinophenyl) -butanone-1 ... 4.0 parts by weight 4,4-diethylthioxanthone ... 0.75 parts by weight 2,4 diethylthioxanthone ... 0 .25 parts by weight Ethylene glycol monobutyl ether ... 65 parts by weight

  When curing the above-described ultraviolet curable resin, a light source such as a mercury lamp or a halogen lamp is usually used, but irradiation is performed depending on the type and thickness of the ultraviolet curable resin, the degree of curing, and the like. What is necessary is just to set suitably the irradiation conditions of ultraviolet rays, such as a wavelength and intensity | strength of ultraviolet rays.

As described above, according to the method of manufacturing the optical substrate 1, the end surfaces 5 c and 5 d of the core 5 can be easily and quickly pressed only by pressing the heated hot plates 33 and 35 against the end surfaces 5 c and 5 d of the core 5. Since it can shape | mold to a flat surface, the manufacturing efficiency of the optical board | substrate 1 can be improved.
Further, since the end surfaces 5c and 5d of the core 5 can be formed into a flat surface at the same time as the flat surface, it is not necessary to perform a separate polishing process, and the number of manufacturing steps of the optical substrate 1 is reduced, and the optical substrate 1 is manufactured. Cost can be kept low.
Further, in the end face forming process, the end faces 5c and 5d of the core 5 are melted and formed into a flat surface by the hot plates 33 and 35 having a simple configuration, so that the constituent materials of the core 5 are limited as in the conventional laser cut. There is no need. Therefore, a highly versatile manufacturing method of the optical substrate 1 that is not affected by the constituent material of the core 5 can be provided.

  Furthermore, the end surfaces 5c and 5d of the core 5 molded into a flat surface can be mirrored only by performing the end surface molding process with the flat surfaces 33a and 35a of the hot plates 33 and 35 inclined with respect to the longitudinal direction of the core 5. Since the surfaces 5c and 5d can be used, the angles of the mirror surfaces 5c and 5d can be set easily and accurately by simply changing the angle of the flat surfaces 33a and 35a of the hot plates 33 and 35 with respect to the longitudinal direction of the core 5. Can do. In particular, the angle can be easily and strictly controlled as compared to the case of forming a tilted mirror surface by conventional laser cutting. Therefore, the reliability of the optical substrate 1 including the mirror surfaces 5c and 5d can be improved, and the optical substrate 1 can be provided at a low cost.

In this embodiment, the end surfaces 5c and 5d of the core 5 formed on a flat surface are inclined with respect to the longitudinal direction of the core 5, but may not be particularly inclined. In this case, in the end surface forming step, the flat surfaces 33a, 35a of the hot plates 33, 35 may be pressed against the end surfaces 5c, 5d of the core 5 in a state of being orthogonal to the longitudinal direction of the core 5.
In addition, the side surfaces 3a and 3b of the substrate body 3 from which the core 5 protrudes are inclined planes 3a and 3b that are inclined with respect to the longitudinal direction of the core 5. However, the present invention is not limited to this. A plane orthogonal to the direction may be formed.

Moreover, in the manufacturing method of the said embodiment, although the case where the separate hot plates 33 and 35 were each pressed on the end surfaces 5c and 5d of the one core 5 was described, the edge part 5a of the several core 5 from the same side surface 3a. When protruding, the flat surfaces 33a of the same hot plate 33 can be simultaneously pressed against the end surfaces 5c of the plurality of cores 5 to simultaneously mold the end surfaces 5c of the plurality of cores 5 into flat surfaces. Therefore, the manufacturing efficiency of the optical substrate 1 can be further improved, and the manufacturing cost can be further reduced. When the same hot plate 33 is inclined and simultaneously pressed against the end faces 5c of the plurality of cores 5, the angles of the mirror surfaces 5c in the plurality of cores 5 can be easily matched.
Further, when the hot plate 33 is individually pressed against the plurality of cores 5, the end surfaces 5c of the cores 5 can be set at different angles, and the optical substrate 1 having various specifications can be easily manufactured. It becomes possible.

Furthermore, although the core 5 is formed in a straight line shape, the present invention is not limited to this, and it is sufficient that at least the end portions 5a and 5b of the core 5 protrude outward from the substrate body 3. It may be arranged in a curved shape inside.
Therefore, the one end portion 5a and the other end portion 5b of the core 5 are not limited to projecting from the two side surfaces 3a and 3b of the substrate body 3 positioned in opposite directions to each other as in the above-described embodiment. 3 may protrude on any surface. That is, for example, the one end portion 5a of the core 5 may be protruded from the side surface 3a of the substrate body 3 and the other end portion 5b may be protruded from the front surface or the back surface of the substrate body 3. The part 5b may protrude from the same side surface 3a.
Further, the cross section of the core 5 is not limited to a substantially circular shape, and may be formed in an arbitrary shape such as a square shape.

  Next, a second embodiment according to the present invention will be described with reference to FIGS. The optical substrate and the manufacturing method thereof according to the second embodiment are different from the first embodiment mainly in the shape of the end face of the core. Here, only the above differences will be mainly described, the same parts as those of the optical substrate 1 of the first embodiment will be denoted by the same reference numerals, and the description thereof will be omitted.

When the optical substrate according to this embodiment is manufactured, the optical waveguide forming step is performed using the same mold as that of the first embodiment, and as shown in FIG. Constitutes protruding from the side surfaces 3a and 3b of the substrate body 3, respectively. The side surfaces 3a and 3b are orthogonal to the longitudinal direction of the core.
Next, as shown in FIG. 6, the end surfaces 5c and 5d of the end portions 5a and 5b of the core 5 protruding from the substrate body 3 are melted by hot air heaters (heating means) 37 and 39 to be formed into a spherical shape. 7 is finished in a lens shape (end surface molding step), the manufacture of the optical substrate 11 shown in FIG. 7 is completed. In this step, the hot air is blown from the hot air heaters 37 and 39 toward the end surfaces 5c and 5d of the core 5 to melt the end surfaces 5c and 5d of the core 5, and the surface tension of the constituent material of the molten core 5 is melted. Thus, the end surfaces 5c and 5d of the core 5 are formed into a spherical shape. Here, since the end surfaces 5c and 5d of the core 5 are formed in a spherical shape by the hot air from the hot air heaters 37 and 39, the end surfaces 5c and 5d of the core 5 having a lens shape are in a mirror state.

  As described above, in the optical substrate 11 in which the end surfaces 5c and 5d of the core 5 have the lens shape, the optical signals entering and exiting the end portions 5a and 5b of the core 5 are transmitted to the end surfaces 5c and 5d of the core 5 having the lens shape. Since the light can be condensed, an optical signal can be efficiently transmitted between a transmission / reception optical device, an optical fiber, or the like including a laser diode or a photodiode connected to the end portions 5a and 5b of the core 5. . Therefore, connection reliability with a transmission / reception optical device, an optical fiber, or the like can be improved.

Moreover, according to the manufacturing method of this optical board | substrate 11, there exists an effect similar to 1st Embodiment. That is, since the end surfaces 5c and 5d of the core 5 protrude from the substrate body 3, the end surfaces 5c and 5d of the core 5 can be easily and quickly spherical by simply blowing hot air to the end surfaces 5c and 5d of the protruding core 5. The lens can be formed into a lens shape, and the manufacturing efficiency of the optical substrate 11 having the above-described light collecting function can be improved.
Further, since the end surfaces 5c and 5d of the core 5 can be formed into a spherical shape at the same time as the spherical surface, it is not necessary to perform a separate polishing process, thereby reducing the number of manufacturing steps of the optical substrate 11 and manufacturing the optical substrate 11. Cost can be kept low.

Further, in the end face forming step, the end faces 5c and 5d of the core 5 are melted and formed into a spherical shape by the hot air heaters 37 and 39 having a simple configuration, so that the optical substrate 1 having high versatility that is not affected by the constituent material of the core 5 is used. The manufacturing method of can be provided.
Furthermore, when the end surfaces 5c of the plurality of cores 5 project from the same side surface 3a, hot air can be blown to the end surfaces 5c of the plurality of cores 5 by the same hot air heater 37, and therefore the end surfaces of the plurality of cores 5 5c can be formed into a spherical shape at the same time. Therefore, in this case, the manufacturing efficiency of the optical substrate 1 can be further improved and the manufacturing cost can be further reduced.

In all the embodiments described above, the optical waveguide forming step is performed using the mold 23. However, the present invention is not limited to this. For example, a sheet-like clad member having a refractive index lower than that of the core 5 is used. The optical waveguide forming step may be performed by sandwiching the core 5 by, for example. In this case, the substrate body 3 is constituted by a clad member that sandwiches the core 5.
Further, the melting of the end surfaces 5c and 5d of the core 5 in the end surface molding process is performed using the hot plates 33 and 35 and the hot air heaters 37 and 39, but the present invention is not limited to this, and a hot iron, burner, etc. Other heating means can also be used. However, it is preferable that the heating means is appropriately selected according to the shape of the core 5 to be molded.

Further, the end surfaces 5c and 5d of the core 5 protruding from the substrate body 3 are formed into a flat surface or a spherical surface in the end surface forming process. However, the present invention is not limited to this. It can be formed into an arbitrary shape according to the specifications of the substrate.
Further, the end surfaces 5c and 5d of the plurality of cores 5 are not limited to be formed in the same shape on the same optical substrate 1 and 11, and for example, the end surfaces 5c and 5d of the plurality of cores 5 have different shapes. You may shape | mold. Even in this case, since the end faces 5c and 5d can be easily formed into arbitrary shapes, the optical substrates 1 and 11 having higher functions can be easily provided.

  In all the embodiments described above, the end surfaces 5c and 5d of the core 5 protruding from the substrate body 3 are both heated and melted to be molded into a predetermined shape. It is more preferable to use a material having a temperature higher than the transition temperature. However, when heating is performed by directly contacting the core 5 like the hot plates 33 and 35, the heating of the core 5 is not easily transmitted to the substrate body 3. There is no particular problem even if the glass transition temperatures of 3 and core 5 are the same.

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

It is explanatory drawing of the manufacturing method of the core used for the manufacturing method of the optical board | substrate which concerns on 1st Embodiment of this invention. It is a schematic sectional drawing which shows an optical waveguide formation process in the manufacturing method of the optical board | substrate which concerns on 1st Embodiment of this invention. It is a schematic sectional drawing which shows an end surface shaping | molding process in the manufacturing method of the optical board | substrate which concerns on 1st Embodiment of this invention. It is a schematic sectional drawing which shows the optical board | substrate which concerns on 1st Embodiment of this invention. In the manufacturing method of the optical substrate concerning a 2nd embodiment of this invention, it is a schematic sectional view showing a state after an optical waveguide formation process is completed. It is a schematic sectional drawing which shows an end surface shaping | molding process in the manufacturing method of the optical board | substrate which concerns on 2nd Embodiment of this invention. It is a schematic sectional drawing which shows the optical board | substrate which concerns on 2nd Embodiment of this invention.

Explanation of symbols

1,11 Optical substrate 3 Substrate body 5 Core 5a One end (end)
5b The other end (end)
5c, 5d End face (mirror face)
33, 35 Hot plate (heating means)
33a, 35a Flat surface 37, 39 Hot air heater (heating means)

Claims (5)

An optical waveguide forming step in which a linear core is disposed inside a substrate body having a lower refractive index than the core, and an end portion in the longitudinal direction of the core protrudes outward from the substrate body;
A method of manufacturing an optical substrate, comprising: an end surface molding step of heating and melting an end surface of the core protruding from the substrate main body by a heating unit and molding the end surface into an arbitrary shape. The heating means comprises a hot plate having a flat surface;
2. The method of manufacturing an optical substrate according to claim 1, wherein, in the end surface forming step, the flat surface of the heated hot plate is pressed against the end surface of the core, and the end surface of the core is formed into a flat surface.   2. The method of manufacturing an optical substrate according to claim 1, wherein, in the end face forming step, the end face of the core is melted by the heating means to be formed into a spherical shape, and the end face of the core is formed into a lens shape. It is manufactured by the method for manufacturing an optical substrate according to claim 2,
An optical substrate, wherein an end surface of the core formed into a flat surface is a mirror surface inclined with respect to a longitudinal direction of the core. It is manufactured by the method for manufacturing an optical substrate according to claim 3,
An optical substrate characterized in that an end surface of the core has a lens shape.

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