JP2007233360A - Optical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device in which the number of steps can be reduced compared with a conventional one, with an enlarged area, and further, cores can be arranged three-dimensionally with uniformity. <P>SOLUTION: A sheet-like optical device is composed of two or more cores and cladding which is arranged around the cores and has a smaller refractive index than the cores, and the cores and a part of the cladding are formed of a thermoplastic resin, and the two or more cores serve as light guides. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet-like flexible optical device used in the field of optical communication and the like.

Conventionally, as a sheet-like optical device used in the field of optical communication, an optical fiber sheet integrated with an optical fiber array has been known. The optical fiber sheet is a sheet-like sheet in which optical fibers are arranged in the width direction through an adhesive or the like and the periphery of the composite is covered with a resin or the like. As a manufacturing method thereof, for example, in a silica-based SI (single index) type optical fiber, the fiber is sequentially manufactured by post-processing of the fiber as described above. A batch forming method is known. (Patent Document 1)
In recent years, with the explosive increase in communication traffic due to the spread of the Internet, an FTTH (fiber to the home) communication network in which the above-described optical fiber reaches the home is being constructed. On the other hand, for connections between and within devices such as computers and electronic exchanges, the current transition from metal cables and wiring such as copper to optical interconnections using fibers and optical waveguides is being promoted. Among them, a flexible polymer optical waveguide formed into a film is being used as an optical interconnection material between boards, boards, chips, and chips. As polymer optical waveguide devices, applications from simple optical wiring to, for example, thermo-optic effect (TO) switches and arrayed waveguide grating variable length filters (AWG-TF) are progressing. As a manufacturing method of these polymer optical waveguides, a selective polymerization method, a method combining reactive ion etching (RIE) and photolithography (Patent Document 2), a direct exposure method (Patent Document 3), and an injection molding method are used. The method (Patent Document 4), the photo bleaching method (Patent Document 5), and the like are known.

However, since these manufacturing methods have a large number of steps, the manufacturing time is long, the manufacturing cost is high, and the core to be the light guide path mainly uses light and thermosetting resin. The core is formed in a two-dimensional plane, and it is difficult to form a polymer waveguide only in a small area. Even if the light guides are arranged three-dimensionally, the manufacturing method is a build-up type, in which the optical waveguides are sequentially laminated by the same operation, or the polymer optical waveguides are laminated and laminated. It was limited to go. Therefore, not only the number of processes is increased, but the former ensures a uniform refractive index distribution as designed in the thickness direction unless the amount and distribution of light and heat for curing the core and cladding are adjusted with high accuracy. However, it is difficult to form the core as it is, and the latter has a problem that the position of the core is shifted unless it is bonded with high accuracy. (Patent Document 6, Patent Document 7, Patent Document 8)
JP-A-60-117202 JP 2004-206016 A JP 2003-185860 A JP 2003-172841 A JP 2004-012635 A Japanese Patent Laid-Open No. 11-183747 JP-A-12-258668 JP 2004-177730 A

  Therefore, an optical device is provided in which the number of steps is small compared to the conventional case, the area can be increased, and the light guides are uniformly arranged three-dimensionally.

  The inventors of the present invention have reached the present invention as a result of intensive studies to achieve the above object. A sheet-like optical device composed of a plurality of cores and a clad having a refractive index smaller than that of the core installed around the core, wherein the core and a part of the clad are formed of a thermoplastic resin, An optical device in which the plurality of cores serve as light guide paths.

  Instead of using mainly heat and photo-curing resins as in the prior art, in the present invention, by using a thermoplastic resin as a central material, a plurality of three-dimensionally large-area and arbitrary light guides can be obtained. A flexible optical device that forms the core becomes possible. Further, as compared with the conventional manufacturing method, alignment of the light guide path in the thickness direction is not required, the number of processes is small, and a plurality of cores are formed in a short time, thereby realizing cost reduction. The optical device of the present invention can provide an optical device particularly suitable for optical information communication applications.

  Details of the present invention will be described below.

  The optical device of the present invention is a sheet-like optical device composed of a core and a clad having a refractive index lower than that of the core installed around the core, and a part of the core and the clad is made of a thermoplastic resin. The optical device is formed, and the core serves as a plurality of arbitrary light guides. An example of a cross-sectional view of the optical device of the present invention is shown in FIG. The core in the optical device of the present invention shown in FIG. 1 is composed of two thermoplastic resins A, while the clad is composed of one thermoplastic resin B and three media C. Moreover, the arbitrary plurality of light guide paths made of the core are the regions 4 surrounded by the regions 1 and 3. As long as the region 4 is formed, the repeating order of the thermoplastic resin B which is a part of the core and the clad may be different from that in FIG. Also, the term “arbitrary” here means that the light guide path may have any geometric shape as long as it functions as an optical device such as a straight line, a curved line, a Y-branch, and a merging structure in the extending direction of the core. means. The refractive index of the clad made of the thermoplastic resin B and the medium C needs to be smaller than the refractive index of the core made of the thermoplastic resin A, and the relative refractive index difference is 0.3% or more. It is necessary. The relative refractive index difference is a value obtained by dividing the refractive index difference between the core and the clad by the refractive index of the clad. Since the clad in the present invention is composed of the thermoplastic resin B and the medium C, the higher refractive index of the clad is adopted. Further, from the viewpoint of reducing the bending radius in the optical circuit, the relative refractive index difference is preferably 1% or more, and more preferably 2% or more. The thermoplastic resin of the optical device of the present invention is polyethylene, polypropylene, polylactic acid, poly (4-methylpentene-1), cyclic polyolefin, polymethyl methacrylate, polyvinyl chloride, polyvinyl alcohol, nylon 6, 11, 12, 66 Polyamide, polystyrene, styrene copolymer polymethyl methacrylate, polycarbonate, polyester, polyarylate, polyvinylidene fluoride, polyethersulfone, polyphenylene sulfide, polyetherimide, polyimide, tetrafluoroethylene-hexafluoropropylene copolymer, etc. Fluororesin such as tetrafluoroethylene-ethylene copolymer and polychlorotrifluoroethylene, fluorinated polyimide, and the like can be used. These may be homopolymers, copolymer polymers, or alloy polymers. Among these, in terms of transparency, cyclic olefin copolymers (for example, Mitsui Chemicals' Appel, polyplastic topas) and norbonene-based monomers that are copolymers of norbornene and ethylene copolymerized with metallocene or Ziegler-Natta catalysts are developed. Cyclic polyolefins obtained by ring metathesis polymerization and hydrogenation (for example, ZEONOR, ZEONEX of Nippon Zeon, Arton of JSR), poly (4-methylpentene-1), polycarbonate, polyester, polymethyl methacrylate, polystyrene, etc. are preferable. Excimer From the viewpoint of laser processability, polyester, polycarbonate, polyethersulfone, polyimide and the like are preferable. Of these, polyesters are particularly preferred because of their high cost.

  The polyester constituting the optical device of the present invention is preferably a polyester obtained by polymerization from a monomer having aromatic dicarboxylic acid or aliphatic dicarboxylic acid and diol as main components. Here, as the aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4′-diphenyl Examples thereof include dicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, and the like. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dodecanedioic acid and the like. Of these, terephthalic acid and 2,6 naphthalenedicarboxylic acid are preferred. These acid components may be used alone or in combination of two or more thereof, and further may be partially copolymerized with oxyacids such as hydroxybenzoic acid.

    Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentanediol. 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis (4- Hydroxyethoxyphenyl) propane, 9,9-bis [4- (2-hydroxyethoxy) phenyl] fluorene, isosorbate, spiroglycol and the like. Of these, ethylene glycol is preferably used. These diol components may be used alone or in combination of two or more.

  Among the above polyesters, polyethylene terephthalate and its polymer, polyethylene naphthalate and its copolymer, polybutylene terephthalate and its copolymer, polybutylene naphthalate and its copolymer, and polyhexamethylene terephthalate and its It is preferable to use a copolymer, polyhexamethylene naphthalate, a copolymer thereof, and the like. Among these, polyethylene naphthalate having a high glass transition point is preferred in terms of excimer laser processability. Further, from the viewpoint of adjusting the refractive indexes of the core and the clad, they may be alloyed and used. For example, a core made of thermoplastic resin A mixed with polyethylene terephthalate and polyethylene naphthalate at a ratio of 8: 2 can be used, and polyethylene terephthalate can be used for a part of the clad made of thermoplastic resin B. The ratio may be appropriately determined according to the adjustment of the refractive index in the optical design.

  The medium C may be any medium as long as it forms an interface between the light guide formed of the core and the refractive index, and may be air, a thermoplastic resin, light, a thermosetting resin, or the like. However, from the viewpoint of optical transmission, it is preferable that the refractive index is closer to a part of the clad made of thermoplastic resin, and the absolute value of the difference in refractive index between the medium C and a part of the clad is preferably 0.01 or less, More preferably, it is 0.005 or less, more preferably equal.

  The manufacturing method of the optical device of the present invention is such that a core made of the thermoplastic resin layer A and a part of the clad made of the thermoplastic resin layer B are alternately arranged in the thickness direction from two extruders using a laminating apparatus. An optical device comprising a step of forming an optical device base material that is laminated in three or more layers, and then extruded into a sheet form in a molten state from the slit portion of the die and solidified, and a step of forming a light guide path on the optical device base material It is a manufacturing method.

  As the extruder, either a single screw extruder or a twin screw extruder may be used. As a means of adjusting the refractive index of the thermoplastic resin used in the present invention, kneading that enables adjustment of the refractive index by compatibilizing (alloying) two or more types of thermoplastic resins having different refractive indexes. There is technology. In such cases, the screw configuration is very important. When alloying, a single screw screw is preferably a dull image type or a Maddox type, and a biaxial screw is preferably a paddle structure in which kneading is strengthened by a combination of paddles. Further, it is preferable that the optical device has as few foreign substances as possible that cause light scattering. As a method for removing foreign matter, vacuum vent extrusion is effective.

  Therefore, as the extruder of the present invention, a twin-screw vent type extruder that is advantageous in terms of alloying and foreign matter removal is most preferable. In addition, as a method for removing the foreign matter, a method of performing filter filtration may be used. By installing the filter between the extruder and the laminating apparatus, foreign substances in the thermoplastic resin that is a part of the core and the clad can be removed. As the filtration accuracy of the filter, it is preferable to use a filter having a filtration accuracy of 20 μm or less from the viewpoint of reducing optical loss. More preferably, it is 5 μm or less. The laminating apparatus for forming the optical device substrate of the present invention can be achieved with a known pinole in a B / A / B three-layer structure, and as a laminating apparatus for forming a further laminated structure, This can be achieved by using a multi-manifold die, a multi-manifold type feed block, and a comb type feed block. From the viewpoint of increasing the thickness accuracy of a part of the core and the clad made of thermoplastic resin, it is most preferable to use a comb-type feed block when the multi-manifold type feed block is 10 layers or more. FIG. 2 shows a top view of a comb type feed block which is a laminating apparatus preferably used in the present invention. FIG. 3 is a side view of the slit plate 7 of the feed block, the short tube 12, the base 13, and the cast drum 14. FIG. 4 shows a front view of the feed block 9, the short tube 12, the base 9, and the cast drum 10.

The manufacturing method of a sheet-like optical device base material is demonstrated in detail using these. In FIG. 2, the polymer A: 5 and the polymer B: 6 supplied from the respective extruders are filled in the manifold 8 in the feed block, respectively, and then the polymer A: 5 and the polymer are fed into the slit plate 7 which is a polymer joining portion. By alternately flowing B: 6, a laminated structure is achieved. However, in FIG. 3 on the side surface, the polymer A flows into only the slit portion 10 in the slit plate 7 from the front side of the paper surface, while the polymer B flows into only the slit portion 11 from the back surface of the paper surface. It is merged as a multilayer flow just before the tube to obtain a laminated structure. A desired laminated structure is designed by adjusting the number of laminations and adjusting the number of slit portions and the thickness of each slit portion by adjusting the gap and length of the slit portions. Next, the laminated polymer flow passes through the short tube 12 and the base 13 and is cooled and solidified on a casting drum as a cooling roll to form a sheet having a laminated structure. (See FIGS. 3 and 4.) At this time, the cross-sectional shape of the polymer flow path in the short tube is preferably a square shape from the viewpoint of uniform layer thickness, and particularly the aspect ratio (the length of the cross-section of the flow path in the sheet width direction). (Length / length in thickness direction) is preferably 1 or more. Further, the flow rate at that time is preferably as low as 5 to 30 kg / hr / cm ² from the viewpoint of obtaining high lamination accuracy. More preferably, the sheet is preferably in close contact with the casting drum by an electrostatic application method in order to maintain the flatness of the sheet at 5 to 15 kg / hr / cm ² . In the electrostatic application method, a voltage of about 3 to 10 kV is applied to a wire such as tungsten to generate an electric field and electrostatically adhere the molten sheet to the casting drum to obtain a cooled and solidified sheet. It is a method. In addition, calendering cast may be performed with a known surface roughness of 0.2S level HCr-plated touch roll. The touch roll pressure at that time is preferably 0.1 MPa or less from the viewpoint of not deforming the core sheet shape. The base is preferably a T-type base from the viewpoint of realizing a uniform layer thickness in the film width direction.

  The method for forming the light guide path on the optical device substrate of the present invention is achieved by providing the medium C. For example, if the medium C is air, this can be achieved by a method of physically cutting a portion corresponding to the medium C from the optical device substrate with a blade or the like, or etching using a laser or the like. If the medium C is a resin, this can be achieved by pouring a resin corresponding to the medium C into the groove after the above process by various coating methods. As a method that does not perform the etching step, it can also be achieved by a photobleaching method that lowers the refractive index of the irradiated core by performing UV irradiation using a laser or the like. Alternatively, it can also be achieved by a method in which the resin structure undergoes phase transition in association with cross-linking curing or melting of the resin by heat.

  In particular, in the method of manufacturing an optical device according to the present invention, laser etching or an etching process using a blade is effective from the viewpoint of formation of an arbitrary light guide and its workability. The laser may be any laser, for example, YAG, He—Ne, carbon dioxide laser. In the present invention, a femtosecond laser or an excimer laser is particularly preferable. A femtosecond laser is light that has a narrow half-value width and provides strong oscillation intensity by aligning phases of light of different wavelengths. Therefore, it is a laser whose processing accuracy is sharp because it decomposes and evaporates the material faster than the diffusion of heat. On the other hand, an excimer laser is a laser that oscillates ultraviolet rays having wavelengths of 193 and 248 nm, respectively, by discharging and exciting an inert gas such as ArF or KrF. This is a laser having a feature that promotes decomposition and evaporation of the polymer because it has high energy and becomes an absorption wavelength band of the polymer material. In the excimer laser, it is preferable to adjust the shape of the laser spot on the workpiece using a phosphor bronze mask during the etching process. The spot shape is preferably rectangular, circular, or elliptical from the viewpoint of flattening the cutting surface. In the line processing, this spot position is achieved by scanning the sample on a straight line. On the other hand, the blade may be made of any material as long as it can cut the thermoplastic resin. For example, glass, stainless steel, diamond and the like are preferable. In particular, a diamond blade that is durable even when using a micron-level blade size that enables high-fine wire grooving is most preferable. Examples of the cutting method include milling, drawing, and turning. Milling is a processing method involving rotation of a blade, drawing is a non-rotating processing method, and turning is a processing method of fixing a blade and rotating a test object. In the present invention, a milling process is preferred in which the end face of the groove having a good sharpness can be cut with little damage to the thermoplastic resin other than the cutting part. As a milling method, it is preferable that the blade is rotated in a spindle manner. As the spindle method, there is a method in which the rotation axis is parallel and perpendicular to the cutting surface. In the present invention, from the viewpoint of the smoothness of the side surface of the groove after milling, it is particularly preferable to use a groove parallel to the rotation axis. The blade width may be selected according to the groove width size of the thermoplastic resin. In the present invention, from the viewpoint that the core diameter for optical transmission is on the micron level, the width is preferably 10 μm or more and less than 1 mm.

  The average roughness of the groove bottom after the etching step of the optical device of the present invention is preferably 500 nm or less. When the thickness is 500 nm or less, the groove side surface is also smoothed, and light loss due to light scattering at the interface between the light guide and the medium C is reduced. More preferably, it is 250 nm or less. More preferably, it is 100 nm or less.

  The optical device substrate of the present invention is formed by forming a protective layer having no light scatterer such as particles on at least one side from the viewpoint of improving the processability of etching by a laser or blade and preventing damage to a part of the cladding or the core. Preferably it is. This is referred to as a protective layer 1. The protective layer 1 may be any resin such as thermoplastic, thermosetting, or photocurable resin, but preferably contains the same type of component as the layer to be adhered from the viewpoint of making it difficult to peel off. More preferably, it is the same thermoplastic resin as a part of the cladding. The forming method may be formed by laminating or coating, but is preferably the outermost layer laminated with pinol or a feed block at the time of melting from the viewpoint of adhesion and process simplification. In the laser etching step of the optical device substrate having the protective layer 1, it is preferable that the protective layer 1 is on the laser irradiation surface side from the viewpoint of workability. After the laser etching step, a tapered groove is formed on the irradiation surface side of the optical device. From the viewpoint of not affecting the cross-sectional shape of the light guide, the thickness of the protective layer 1 is preferably 5 μm or more, while 500 μm or less is preferable from the viewpoint of ease of handling. More preferably, they are 30 micrometers or more and 200 micrometers or less.

  In the optical device of the present invention, only a two-dimensional arrangement of light guides can be realized with a three-layer structure of part of the clad / core / part of the clad. In this case, in order to increase the transmission capacity, the width is increased in order to arrange the light guides horizontally. Therefore, from the viewpoint of increasing the transmission capacity in a small space, it is preferable that a part of the core and the clad are alternately laminated in five or more layers in the thickness direction so that a three-dimensional arrangement of the light guides is possible. If the number of layers increases too much, the problem of processing accuracy and the thickness of the optical device itself increase, and flexibility is lost. Therefore, the upper limit is preferably 100 layers or less. The method of obtaining a laminated structure of five or more layers is achieved by increasing the number of manifold portions by the number of layers to be formed when using a known multi-manifold die or multi-manifold type feed block. However, when the number of layers increases, there is a problem that the apparatus becomes large, and when the number of layers is 10 or more, comb type feed blocks are most preferable. This can be easily achieved by increasing the number of slits. Moreover, it is preferable that the width | variety of the slit which forms an outermost layer part is 2 times or more of other slit widths from a viewpoint of equalizing the thickness of the core of a thickness direction.

  In the optical device of the present invention, it is preferable that a plurality of light guide paths are three-dimensionally arranged in the thickness direction and / or the width direction of the optical device. The thickness direction of the optical device is a direction in which a part of the core and the clad are laminated, and the width direction is an in-plane direction that is perpendicular to the direction in which the core extends. In the future, it is preferable to appropriately adjust the arrangement interval at a highly integrated interval from the viewpoint of increasing the amount of information. The interval between the arrays includes the distance between the light guide paths in the thickness direction and the distance between the light guide paths in the width direction. The former corresponds to the distance between the center points of the core sandwiching a part of the cladding in the thickness direction, and the latter corresponds to the distance between the center points of the cores arranged in the width direction across the medium C. At present, the distance between the centers of the light guides, which is a standard for a V-groove substrate such as a normal fiber array, is 125 to 127 μm, or an array interval corresponding to 250 μm, and the light guides are arranged in the thickness direction and / or the width direction. It is preferable in terms of specifications that the elements are arranged three-dimensionally. The number of light guide paths may be adjusted as appropriate to correspond to the number of fiber arrays to be connected. For example, when connecting a 16-core fiber array, there are 16 or more light guide paths in the thickness direction and / or the width direction. is necessary. In addition, the achievement method is achieved by providing a region of the medium C to a desired distance and a desired depth on an optical device substrate having a five-layer structure or more of a part of cladding / a part of core / a part of cladding. The

  The thickness of the core of the optical device of the present invention is preferably 1 μm or more and 300 μm or less, and the thickness of a part of the cladding is preferably 1 μm or more and 500 μm or less from the viewpoint of the core diameter of the optical fiber to be connected. For example, in the case of a single mode optical fiber, the core thickness is preferably around 6 to 10 μm and the cladding is preferably around 55 μm, and in the case of a multimode optical fiber, the core thickness is around 60 μm and the thickness of a part of the cladding. Is more preferably around 30 μm. Moreover, the achievement method is achieved by adjusting the discharge amount of the thermoplastic resin A serving as the core and the thermoplastic resin B serving as a part of the clad supplied from the two extruders. Moreover, as a method of adjusting the overall thickness, by adjusting the roll peripheral speed of the cooling roll when it is extruded in a molten state from the slit portion of the T-shaped base and then solidified by the cooling roll. Achieved.

  In addition, the optical device of the present invention preferably has a layer containing particles on at least one surface from the viewpoint of appropriate winding characteristics and preventing optical devices from causing external damage due to a blocking phenomenon. This is referred to as a protective layer 2. The concentration of the particles is 10 wt.% From the viewpoint of making it difficult to cause deterioration in workability of the optical device substrate due to light scattering while forming appropriate protrusions necessary for preventing blocking and imparting slipperiness. % To 0.01 wt. % Range is preferred. The above range is achieved by adjusting the weight ratio of the resin solid component and the particle solid component. Further, the primary average particle diameter of the particles used is preferably 0.01 μm or more and 2 μm or less from the same viewpoint. More preferably, it is 0.05 to 1.5 μm. The evaluation method of the slipperiness can be determined by parameters such as surface roughness, dynamic friction coefficient, or static friction coefficient. From the viewpoint of imparting slidability, both the dynamic friction coefficient and the static friction coefficient are preferably 1 or less, and more preferably 0.7 or less. The protective layer 2 may be any resin such as thermoplastic, thermosetting, or photocurable resin, but preferably contains the same type of component as the layer to be adhered from the viewpoint of making it difficult to peel off. In addition, from the viewpoint of dropout of particles and easy slipperiness, the thickness is preferably 0.1 μm or more and 10 μm or less. The method of forming a layer containing particles on the surface is achieved, for example, by coating a coating containing inorganic particles such as silica on the surface of the outermost layer on one side of the optical device or the optical device substrate. It can also be achieved by incorporating particles in the outermost resin layered by pinol or feed block during melt extrusion. Particle types can be broadly classified into organic and inorganic lubricants. As the shape, shape particles such as aggregated particles, spherical particles, beaded particles, complex particles, and scale-like particles can be used. In addition, the inorganic materials include silicon oxide (including silica), calcium carbonate, titanium oxide, alumina, zirconia, aluminum silicate, mica, clay, talc, barium sulfate, etc., and the organic materials include polyimide. Resins, olefins or modified olefin resins, cross-linked or non-cross-linked polystyrene resins, cross-linked or non-cross-linked acrylic resins, fluororesins, silicone resins, etc., and stearamide, oleic amide, fumar as organic lubricants Examples include various amide compounds such as acid amides. In particular, in the optical device of the present invention, from the viewpoint of suppressing light scattering, it is preferable to use particles in which the difference between the refractive index of the particles and the refractive index of the resin layer containing the particles is 0.01 or less. Further, from the viewpoint of effectively imparting slipperiness, a true spherical shape or an agglomerated shape is preferable, and silica particles are preferable from the viewpoint of cost and versatility.

  In the laser etching process of the optical device substrate having the protective layer 2, it is preferable that the protective layer 2 is not provided on the laser irradiation surface side from the viewpoint of workability.

  The optical device of the present invention preferably has a length of 1 m or more in the traveling direction of the light guide, which is also the extending direction of the core. The polymer optical waveguide as a device is usually used within a range of several centimeters to several tens of centimeters, but from the viewpoint of productivity and the like, an optical device having a length of 1 m or more is manufactured at a time, and then divided. It is preferable from the viewpoint that it can be supplied to users in a general purpose and inexpensive manner. More preferably, it is 2 m or more. As the achievement method, it is achieved by using an optical device substrate obtained by a melt extrusion method capable of an infinite length in the extending direction, but the longer the optical device length, The thickness unevenness of the optical device substrate itself is increased. In order to suppress the thickness variation of the core due to this unevenness in thickness, the unevenness in thickness is preferably within 10%. More preferably, it is within 5%. The thickness unevenness is a rate of change in thickness and is a value obtained by dividing the difference between the maximum thickness and the minimum thickness by the average thickness. Here, the thickness means the width of the optical device in the direction perpendicular to the surface having the maximum area in the optical device. As a method of setting the thickness unevenness within the above range, the draft ratio, which is the ratio of the lip gap of the die and the sheet thickness of the optical device substrate, is 1 or more and less than 20, more preferably less than 10. It is.

  The optical device of the present invention preferably contains a UV absorber from the viewpoint of increasing the processing accuracy of the excimer laser. The UV absorber is an ultraviolet absorber and is sometimes called a weathering agent or a fluorescent brightening agent.

   In the present invention, it is particularly preferable to use a benzophenone-based, benzotriazole-based and triazine-based UV absorber in an amount of about 0.01 to 1% by weight based on the thermoplastic resin used in the present invention. Examples of the benzophenone series include 4-methoxy-2-hydroxybenzophenone, 4-methoxy-2-hydroxybenzophenone-5-sulfonic acid, 4-methoxy-2-hydroxybenzophenone-5-sulfonic acid (trihydrate), 2 , 4-Dihydroxybenzophenone, 4,4'-dimethoxy 2,2'-dihydroxybenzophenone, 4,4'-dimethoxy-2,2'-dihydroxy-5,5'-disulfonic acid benzophenone disodium, 2,2'- 4,4′-tetrahydroxybenzophenone, sodium hydroxymethoxybenzophenone sulfonate, octabenzone, 2-hydroxy-4-m-octoxy-benzophenone, 2-hydroxy-4-n-octoxybenzophenone and the like. The benzotriazole series includes 2- (2H-benzotriazol-2-yl) -p-cresol, 2- (2H-benzotriazol-2-yl) -4-6-bis (1-methyl-1- Phenylethyl) phenol, 2- [5-chloro (2H) -benzotriazol-2-yl] -4-methyl-6- (tert-butyl) phenol, 2,4-di-tert-butyl-6- (5 -Chlorobenzotriazol-2-yl) phenol, 2- (2H-benzotriazol-2-yl) -4,6-tert-pentylphenol, 2- (2H-benzotriazol-2-yl) -4- (1 , 1,3,3-tetramethylbutyl) phenol, 2,2'-methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol] 2 (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) 5 chlorobenzotriazole, 2 (2'-hydroxy-3'5-di-tert-butyl-phenyl) 5 chlorobenzotriazole, 2 (2'-Hydroxy-5'-methylphenyl) benzotri Tetrazole, 2- (2-hydroxy-5-octylphenyl) - benzotriazole - such as Le, and the like. Further, triazines include 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol, 2- [4,6-bis (2 , 4-Dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 1,6-hexanediamine, N, N'-bis (1,2,2, 6,6-pentamethyl-4-piperidyl), polymers morpholine-2,4,6-trichloro-1,3,5-triazine and the like, but are not limited thereto. Two or more of the above-mentioned components can be mixed and used.

  In the optical device of the present invention, a part other than the clad thermoplastic resin is preferably a curable resin. For example, as a photocurable type, methacrylic resin, photocurable polychlorobiphenyl, alicyclic epoxy resin, photocationic polymerization initiator, acrylate resin (containing Si, F), photoradical, polymerization initiator, fluorinated polyimide, etc. Can be used. Further, as the thermosetting type, any resin such as epoxy, phenol, urethane, acrylic, and polyester containing a crosslinking agent may be used.

  In particular, the medium C, which is a part of the clad formed in the optical device of the present invention, is preferably formed using at least one of urethane resin, polyester resin, and acrylic resin, and each may be used alone, Two types of resins that are different from the viewpoint of adjusting the refractive index, for example, a polyester resin and a urethane resin, a polyester resin and an acrylic resin, or a urethane resin and an acrylic resin may be used in combination. Is preferred.

  In the optical device of the present invention, the urethane resin that can be preferably used as a constituent component of the medium C is not particularly limited as long as it is a water-soluble or water-dispersible urethane resin having an anionic group. Is obtained by copolymerizing a polyol compound and a polyisocyanate compound. Specifically, a urethane resin whose affinity for water is increased by introducing a carboxylate group, a sulfonate group, or a sulfuric acid half ester base can be used. The content of the carboxylate group, sulfonate group, or sulfuric acid half ester base is preferably 0.5 to 15% by weight from the viewpoint of dispersibility in the resin and affinity for water.

  Examples of the polyol compound used for the urethane resin include polyethylene glycol, polypropylene glycol, polyethylene / propylene glycol, polytetramethylene glycol, hexamethylene glycol, hexamethylene glycol, tetramethylene glycol, 1,5-pentanediol, diethylene glycol, and triethylene. Examples include glycol, polycaprolactone, polyhexamethylene adipate, polytetramethylene adipate, trimethylolpropane, trimethylolethane, glycerin, and acrylic polyol.

  Examples of the polyisocyanate compound used for the urethane resin include tolylene diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, diphenylmethane diisocyanate, an adduct of tolylene diisocyanate and trimethylolpropane, an adduct of hexamethylene diisocyanate and trimethylolethane, and the like. Can be used.

  The urethane resin may contain a chain extender or a crosslinking agent in addition to the polyol compound and the polyisocyanate compound.

  Here, ethylene glycol, propylene glycol, butanediol, diethylene glycol, ethylenediamine, diethylenetriamine, or the like can be used as the chain extender or crosslinking agent.

  As a method for producing a urethane resin having an anionic base, for example, a method using a compound having an anionic group in polyol, polyisocyanate, chain extender, etc., an unreacted isocyanate group and an anionic group of the produced urethane resin are used. Although it can manufacture using the method of making the compound which has it react, or the method of making the group which has active hydrogen of the urethane resin, and a specific compound etc., it does not specifically limit.

  In addition, examples of the urethane resin having an anionic group include a polyol having a molecular weight of 300 to 20000, a polyisocyanate, a chain extender having a reactive hydrogen atom, a group that reacts with an isocyanate group, and a compound having at least one anionic group. The resin consisting of is particularly preferred.

  The anionic group in the urethane resin is preferably a sulfonic acid group, a carboxylic acid group, and ammonium salts, lithium salts, sodium salts, potassium salts, or magnesium salts thereof, and particularly preferably a sulfonic acid group.

  The amount of the anionic group in the polyurethane resin is preferably 0.05% by weight to 8% by weight. If it is less than 0.05% by weight, the water dispersibility of the urethane resin tends to be poor, and if it exceeds 8% by weight, the water resistance of the resin is inferior or the blocking phenomenon that the resin layers adhere to each other tends to occur. .

  In the optical device of the present invention, the acrylic resin that is preferably used as a constituent component of the medium C, the monomer component constituting the acrylic resin includes, for example, alkyl acrylate, alkyl methacrylate (the alkyl group is a methyl group, an ethyl group, n -Propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, 2-ethylhexyl group, lauryl group, stearyl group, cyclohexyl group, phenyl group, benzyl group, phenylethyl group, etc.) -Hydroxy group-containing monomers such as hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, acrylamide, methacrylamide, N-methylacrylamide, N-methyl Amide group-containing monomers such as methacrylamide, N-methylolacrylamide, N-methylolmethacrylamide, N, N-dimethylolacrylamide, N-methoxymethylacrylamide, N-methoxymethylmethacrylamide, N-phenylacrylamide, N, N -Amino group-containing monomers such as diethylaminoethyl acrylate and N, N-diethylaminoethyl methacrylate, epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, acrylic acid, methacrylic acid and salts thereof (lithium salt, sodium salt, potassium salt, etc. And a monomer containing a carboxyl group thereof or a salt thereof, and the like, and these are used by (co) polymerization using one kind or two or more kinds. Furthermore, other types of monomers can be used in combination as long as the effects of the present invention are not impaired.

  Examples of other types of monomers include epoxy group-containing monomers such as allyl glycidyl ether, sulfonic acids such as styrene sulfonic acid, vinyl sulfonic acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.). Monomers containing a carboxylic group such as crotonic acid, itaconic acid, maleic acid, fumaric acid and salts thereof (lithium salt, sodium salt, potassium salt, ammonium salt, etc.) or a salt thereof, Monomers containing acid anhydrides such as maleic anhydride and itaconic anhydride, vinyl isocyanate, allyl isocyanate, styrene, vinyl methyl ether, vinyl ethyl ether, vinyl trisalkoxysilane, alkyl maleic acid monoester, alkyl fumar Acid monoester, acrylonitrile, methacrylonitrile, alkyl itaconic acid monoester, vinylidene chloride, vinyl acetate, etc. can be used vinyl chloride.

  In addition, as the acrylic resin that can be used in the present invention, a modified acrylic copolymer, for example, a block copolymer modified with polyester, urethane, epoxy, or the like, a graft copolymer, or the like can also be used.

  Among these, preferable acrylic resins used in the present invention include copolymers selected from methyl methacrylate, ethyl acrylate, n-butyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N-methylol acrylamide, and acrylic acid.

  In the present invention, the acrylic resin is preferably dissolved, emulsified or suspended in water and used as a water-based acrylic resin liquid from the viewpoint of environmental pollution and explosion-proof properties during application. Such water-based acrylic resins are copolymerized with monomers having a hydrophilic group (such as acrylic acid, methacrylic acid, acrylamide, vinyl sulfonic acid and salts thereof), emulsion polymerization using reactive emulsifiers and surfactants, and suspension polymerization. It can be produced by a method such as turbid polymerization or soap-free polymerization.

  In the optical device of the present invention, the medium C is preferably a resin mainly composed of a polyester resin. By using the polyester resin, the adhesion between the core and a part of the clad can be improved, and in particular, the refractive index can be made equal to a part of the clad. Here, the polyester resin used has an ester bond in the main chain or side chain, and can be arbitrarily selected from conventionally known polyester resins.

  As the acid component constituting the polyester resin, aromatic, aliphatic, and alicyclic dicarboxylic acids and trivalent or higher polyvalent carboxylic acids can be used.

  As aromatic dicarboxylic acids, terephthalic acid, isophthalic acid, orthophthalic acid, phthalic acid, 2,5-dimethylterephthalic acid, 1,4-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,2 -Bisphenoxyethane-p, p'-dicarboxylic acid, phenylindanedicarboxylic acid, etc. can be used. From the viewpoint of the strength and heat resistance of the primer layer, these aromatic dicarboxylic acids are preferably polyesters that occupy 30 mol% or more, more preferably 35 mol% or more, particularly preferably 40 mol% or more of the total dicarboxylic acid component. It is preferable to use it.

  Examples of the aliphatic and alicyclic dicarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, dimer acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like, and ester-forming derivatives thereof can be used.

  Examples of the glycol component of the polyester resin preferably used as the constituent component of the medium C include ethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, 1,3-butanediol, and 1,4-butane. Diol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 2,4-dimethyl- 2-ethylhexane-1,3-diol, neopentyl glycol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 3-methyl-1 , 5-pentanediol, 2,2,4-trimethyl -1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 4,4'-thiodiphenol, bisphenol A, 4,4'-methylenediphenol, 4,4 '-(2-norbornylidene) diphenol, 4,4'-dihydroxybiphenol, o-, m-, and p -Dihydroxybenzene, 4,4'-isopropylidenephenol, 4,4'-isopropylidenebin diol, cyclopentane-1,2-diol, cyclohexane-1,2-diol, cyclohexane-1,4-diol, etc. are used. be able to.

  In addition, the polyester resin used as a constituent of the medium C is preferably used as an aqueous liquid as a coating liquid. In this case, in order to facilitate water-solubilization or water-dispersion of the polyester resin, a sulfonate group is used. It is preferable to copolymerize a compound containing or a compound containing a carboxylate group.

  Here, examples of the compound containing a carboxylate group include trimellitic acid, trimellitic anhydride, pyromellitic acid, pyromellitic anhydride, 4-methylcyclohexene-1,2,3-tricarboxylic acid, trimesic acid, 1 , 2,3,4-butanetetracarboxylic acid, 1,2,3,4-pentanetetracarboxylic acid, 3,3 ′, 4,4′-benzophenonetetracarboxylic acid, 5- (2,5-dioxotetrahydro Furfuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic acid, 5- (2,5-dioxotetrahydrofurfuryl) -3-cyclohexene-1,2-dicarboxylic acid, cyclopentanetetracarboxylic acid, 2,3,6,7-naphthalenetetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid, ethylene glycol bistrimethyl Tate, 2,2 ′, 3,3′-diphenyltetracarboxylic acid, thiophene-2,3,4,5-tetracarboxylic acid, ethylenetetracarboxylic acid and the like, or alkali metal salts, alkaline earth metal salts thereof, Examples thereof include, but are not limited to, ammonium salts.

  Examples of the compound containing a sulfonate group include sulfoterephthalic acid, 5-sulfoisophthalic acid, 4-sulfoisophthalic acid, 4-sulfonaphthalene-2,7-dicarboxylic acid, sulfo-p-xylylene glycol, 2 -Sulfo-1,4-bis (hydroxyethoxy) benzene and the like, or alkali metal salts, alkaline earth metal salts, and ammonium salts thereof can be used, but are not limited thereto.

  In the present invention, as the polyester resin used in the medium C, a modified polyester copolymer such as a block copolymer modified with acrylic, urethane, epoxy, or the like, a graft copolymer, or the like can also be used.

  Preferred polyester resins used for medium C are selected from terephthalic acid, isophthalic acid, sebacic acid, 5-sodium sulfoisophthalic acid as the acid component, and ethylene glycol, diethylene glycol, 1,4-butanediol, and neopentyl glycol as the glycol component. Examples thereof include copolymers. When water resistance is required for the resin layer A, a copolymer having trimellitic acid as its copolymer component can be suitably used instead of 5-sodium sulfoisophthalic acid.

  In the optical device of the present invention, the method for producing the polyester resin used for the medium C is not particularly limited, and for example, it can be produced by the following production method. That is, a polyester resin composed of terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid as the dicarboxylic acid component, and ethylene glycol and neopentyl glycol as the glycol component will be described as follows: terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid A first stage in which ethylene glycol or neopentyl glycol is directly esterified, or terephthalic acid, isophthalic acid, 5-sodium sulfoisophthalic acid and ethylene glycol or neopentyl glycol are transesterified, and It can be produced by a method of producing the reaction product by the second stage of polycondensation reaction.

  At this time, as the reaction catalyst, for example, alkali metal, alkaline earth metal, manganese, cobalt, zinc, antimony, germanium, titanium compound, or the like can be used.

  Polyester resins having a large amount of carboxylic acid at the terminal and / or side chain are preferably used. Examples of methods for obtaining these are JP-A-54-46294 and JP-A-60-209073. JP-A-62-240318, JP-A-53-26828, JP-A-53-26829, JP-A-53-98336, JP-A-56-116718, JP-A-61-124684 And a method of copolymerizing a trivalent or higher polyvalent carboxylic acid described in JP-A-62-240318. Of course, methods other than these methods may be used.

  The intrinsic viscosity of the polyester resin used in the medium C according to the present invention is not particularly limited, but is preferably 0.3 dl / g or more, more preferably 0.35 dl / g or more, particularly preferably in terms of adhesiveness. Is 0.4 dl / g or more.

  Moreover, it is preferable that the glass transition temperature (Tg) of a polyester resin is 0-130 degreeC, More preferably, it is 0-80 degreeC. When Tg is less than 0 ° C, for example, heat-resistant adhesiveness may be inferior, or a blocking phenomenon may occur in which resin layers adhere to each other. Conversely, when it exceeds 130 ° C, the stability and water dispersibility of the resin may be inferior. is there.

  Examples of the coating method for providing the medium C in the optical device of the present invention include spin coating, reverse coating, gravure coating, rod coating, bar code, Mayer bar code, die coating, spray coating, A dip coating method or the like can be used.

  From the viewpoint of losing the return light during optical joining or from the viewpoint of optical coupling accompanied by optical path conversion by reflection at an inclined end face, the optical device of the present invention has an end face that is perpendicular to the perpendicular to the thickness direction (surface of the optical device). It is preferable that the inclined end face is inclined at an angle of 5 ° or more and 45 ° or less (with respect to the straight direction). Here, the angle is an angle between the inclined surface and the perpendicular in the plane of the thickness direction and the extending direction of the optical device. When this angle is too small, return light is generated. Conversely, when the angle is too large, the angle is more preferably 8 ° or more and 12 ° or less from the viewpoint of reducing straight light. The inclined end face is that the end face portion for inputting and outputting light is inclined in the optical device of the present invention. If the place in an optical device is shown, it will become the start point and end point of an extending direction. The achievement method can be achieved by cutting with a microtome and polishing with a polishing apparatus, and further transferring to a metal mirror surface above the glass transition temperature of the resin. As for the abrasive grains used in the polishing apparatus, when the object to be polished is a thermoplastic resin, it is preferable to use silica or alumina from the viewpoint of its weak hardness. The roughness on the polishing side is finally # 8000 or more. Is preferably used. In addition, the average roughness of the surface of the end face after polishing is preferably 500 nm or less, more preferably 100 nm or less, from the viewpoint of reducing insertion loss. By such end face processing, light input / output to / from an optical device with very little light insertion loss can be easily achieved.

  Furthermore, the optical device of the present invention preferably has a breaking elongation of 10% or more from the viewpoint of ensuring flexibility. If it is less than 10%, it is easily broken by a weak bending stress, and therefore, it is more preferably 20% or more. The achievement method is achieved by using a single resin having a high breaking elongation as an alloy or as a single resin for either thermoplastic resin A or thermoplastic resin B. This is achieved by appropriately adjusting the volume fraction of the resin having a high elongation at break.

  The wavelength of light used in the optical device of the present invention is preferably 850 nm. Usually, the wavelengths used for optical communication are 1.55 μm and 1.31 μm. However, since the optical device of the present invention uses a thermoplastic resin, generally, the light absorption edge is in the near infrared region. Often has. Therefore, it is preferable to use a wavelength of 1200 nm to 400 nm which is a wavelength in the near infrared to visible light region. In particular, it is preferable for the optical device of the present invention to use light having a wavelength of 850 nm, which has a feature of low light absorption and large transmission capacity.

  In the optical device of the present invention, when the light used is polarized light, the difference in refractive index between the thickness direction of the core and the refractive index in the width direction is preferably 0.005 or more from the viewpoint of polarization dependence. . The achieving method is achieved by stretching the obtained optical device substrate in at least one direction in the width direction or the extending direction. The stretching ratio is preferably 3 times or less, and the stretching temperature is achieved by carrying out at or above the glass transition temperature of the thermoplastic resin used. In addition, heat relaxation treatment may be performed.

  The optical device of the present invention is in the field of optical information communication modules such as a switch element, a splitter such as a splitter, an arrayed waveguide type diffraction grating (AWG), a directional coupler, and a waveguide pitch interval converter (PCLA). It is preferable that the optical device is used in the above. Furthermore, an optical mounting circuit using the present optical device may be used. An optical integrated circuit in which these are integrated may be used. Furthermore, the optical device according to the present invention is preferably used for a system LSI package with built-in optical I / O, an optical backplane, and further for optical interconnection in a CPU. In particular, consumer devices are preferably applied to mobile phones, games, home appliances, etc., but are not limited.

Hereinafter, an optical device according to an embodiment of the present invention will be described.
[Methods for measuring physical properties and methods for evaluating effects]
The characteristic value evaluation method and the effect evaluation method are as follows.

(1) Lamination thickness, number of laminations, lamination structure The layer structure of the sheet | seat was calculated | required by electron microscope observation about the sample which cut out the cross section using the microtome. That is, using a field emission scanning electron microscope JSM-6700F (manufactured by Jeol Co., Ltd.), the sheet cross section was magnified 200 to 1000 times, a cross-sectional photograph was taken, and the layer configuration and each layer thickness were measured. Average values were adopted for the layer thickness of the thermoplastic resin A serving as a plurality of cores and the layer thickness of the thermoplastic resin B serving as a part of the cladding, respectively.

(2) Refractive Index of Thermoplastic Resin and Medium The resin having the same composition as that supplied to the configuration of the laminated structure of the optical device was measured according to the JIS K7142 (1996) A method for each single resin to be evaluated.

(3) Loss It was carried out in accordance with JIS C6823 (1999) cut-back method (IEC 60793-C1A) in an environment of 25 ° C. and 65% RH. A fixed wavelength laser having a wavelength of 850 nm was used as the light source. In the measurement, the fiber connector corresponding to the core thickness and the sample were aligned. The aligning machine was manufactured by using Suruga Seiki. In order to reduce insertion loss, matching oil was used between the sample and the fiber. The measurement results were judged according to the following criteria. When there are multiple light guides, the value with the least loss was adopted.
If it is less than 0.5 dB / cm,
Those that are less than 1 and 0.5 dB / cm or more are Δ
What is 1 dB / cm or more is x.

(4) Sheet thickness fluctuation Anritsu Co., Ltd. film thickness tester “KG601A” and electronic micrometer “K306C” were used, and an optical device substrate sampled 30 mm wide and 3 m long in the longitudinal direction of the sheet was sampled in 0.1 s increments. The thickness was continuously measured at a sheet scanning speed of 1.5 m / min. The change rate of the sheet thickness was a value (%) obtained by dividing the difference between the maximum thickness and the minimum thickness within the sheet length of 2 m by the average thickness and multiplying by 100. In addition, about the change rate of this sheet thickness, it measured by n number 5 times.

(5) Elongation at break The elongation at break was measured at 25 ° C. and 65% RH using an Instron type tensile tester (Orientec Co., Ltd., film tensile strength automatic measuring device “Tensilon AMF / RTA-100”). The measurement was performed in accordance with JIS-K7127 under the following environment. In each of the longitudinal direction of the sheet (MD direction: Machine Direction) and the width direction of the sheet (TD direction: Transvers Directors), a sheet which is an optical device substrate having a width of 10 mm is stretched under the conditions of 50 mm between the test lengths and a pulling speed of 300 mm / min. The elongation at break was determined. In addition, n number shall be 5 times and MD. The average value including TD was adopted.

(6) Surface roughness of groove bottom surface The grooved processed surface of the optical device base material after the etching process was turned upward, and the sample was fixed on a glass substrate. This sample was observed using an ultra-deep shape measuring microscope VK-8500 (manufactured by KEYENCE) with an objective lens 20 times and a vertical resolution of 20 nm and a focal point aligned with the groove bottom surface. Subsequently, the surface roughness of the groove bottom surface was measured using the attached image measurement / analysis software VK-H1W. As measurement conditions, 10 points of arithmetic average roughness in a region of about 10 × 10 mm to 40 × 40 mm were measured, and those values averaged were adopted as the surface roughness.

(7) Shape of formed light guide path Using the above-mentioned scanning electron microscope, it was confirmed whether the shape of the light guide path was a quadrangle having a sharp angle. A rectangular cross-sectional shape having a design guideline in which the boundary line between the light guide path and the medium C is kept perpendicular to the laminated interface of a part of the core and clad made of thermoplastic resin. In addition, a case where the angle between the boundary line between the light guide path and the medium C and the laminated interface that is the bottom of the light guide path is 90 ± 5 degrees was determined to be a rectangle. All the light guides formed based on this standard were evaluated, and the optical device was evaluated according to the following standard.
All cross-sectional shapes of the light guide are square
50% of the light guide is tapered △
No light guide is formed ×.

[Example 1]
Polyethylene terephthalate was used as a thermoplastic resin B as a part of the cladding, and a polymer alloy in which 20% by weight of polyetherimide was mixed with polyethylene terephthalate as a thermoplastic resin A as a core was used. (Thermoplastic resins A and B are both particle-free). Thermoplastic resins A and B are melted at 280 ° C. in each twin-screw vent type extruder, passed through 5 sheets of FSS type leaf disk filters (filtration accuracy 10 μm), and the discharge ratio is thermoplastic with a gear pump. While weighing so that resin A composition / thermoplastic resin B composition = 5/1, they were merged in a five-layer comb-type feed block to obtain a laminated body alternately laminated in the thickness direction. The breakdown is a laminate having a periodic structure in which two layers of thermoplastic resin A and three layers of thermoplastic resin B are alternately laminated in the thickness direction, and the outermost layer is thermoplastic resin B. Further, as the protective layer 2 from the third extruder, the thermoplastic resin C obtained by adding 0.02% by weight of agglomerated silica having an average particle diameter of 1.2 μm to the thermoplastic resin B is brought to the outermost layer portion on one side. Were combined from a two-layer composite pinol (five layer laminate / protective layer 2) under the feed block to obtain a laminate composed of a total of six layers. The cross-sectional shape of the polymer flow path at this time was a square shape having an aspect ratio (length in the width direction / length in the thickness direction) of 2. Moreover, the discharge amount of the laminated resin passing through the cross-sectional area within a unit time was 20 kg / hr / cm ² . After the laminate is supplied to a T-die and formed into a sheet shape, light is an unstretched sheet which is rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatic applied voltage of 8 kV with a wire. A device substrate was obtained. In addition, the draft ratio at this time was 8, and the obtained sheet | seat thickness was 131 micrometers. The length of the collected optical device substrate was 5 m or more (hereinafter, the length of the optical device substrate collected in Examples 1 to 9 was the same). Table 1 shows the structure of the layer of the obtained optical device substrate.

Next, using an excimer laser with a wavelength of 248 nm, two grooves of depth 120 μm × width 50 μm × length 5 cm were formed at intervals of 50 μm to form concave and convex shapes. That is, the width of the convex portion serving as the width of the light guide path is 50 μm. In the etching process, laser was irradiated from the surface not containing particles. A laser that emits a pulse wave with a pulse width of 20 ns and an intensity of 350 mJ in one shot was used. The laser conditions were set to a constant frequency of 197 Hz, and the irradiated part was scanned to form grooves. The phosphor bronze mask pattern used was a 1 mm (length direction) × 50 μm (width direction) rectangle when projected onto an optical device substrate at a reduction ratio of 5. Further, a polyester C low molecular weight compound was dissolved in ethyl acetate, poured into this groove, and dried at a temperature of less than 100 ° C. to obtain medium C. It was confirmed that two light guides were formed above and below in the thickness direction. The results of the obtained optical device are shown in Table 1.
The prescription of medium C is shown below.
Polyester urethane (Mitsui Takeda Chemical)
(I) Bamboo rack U25 (polyester polyol)
(Ii) Takenate D140N (isocyanate)
(Iii) Dispersion with ethyl acetate (i) / (ii) / (iii) = 1 / 0.8 / 1.

[Example 2]
The polymer alloy of the thermoplastic resin A of Example 1 was changed to a mixture of polyethylene terephthalate and polyethylene naphthalate in a weight ratio of 8: 2, and the thermoplastic resin B was changed to polyethylene terephthalate with a triazine UV absorber. 1 wt. Of 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol. % Was added. (Non-particles in thermoplastic resins A and B) Further, using a three-layer composite pinol without using a comb-type feed block in the laminating apparatus, thermoplastic resin B / thermoplastic resin A / thermoplastic resin B 3 A layer composite sheet-like optical device substrate was formed. In addition, the draft ratio at this time was 10, and the obtained sheet | seat thickness was 130 micrometers. Table 1 shows the layer structure. As other film forming parameters, values similar to those in Example 1 were used. Next, using an excimer laser in the same manner as in Example 1, two grooves each having a depth of 100 μm, a width of 50 μm, and a length of 5 cm were formed at intervals of 50 μm to form concave and convex shapes. Thereafter, a light guide was produced in the same manner as in Example 1. It was confirmed that one light guide was formed at the center in the thickness direction. The results of the obtained optical device are shown in Table 1.

[Example 3]
1 wt. Of thermoplastic resin A with triazine UV absorber 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol. An optical device substrate having a sheet thickness of 131 μm was obtained in the same manner as in Example 1 except that% addition was performed. Table 1 shows the layer structure.

  Next, using a femtosecond laser, a depth of 120 μm × length of 1. mm so that the width of the convex portion is 100 μ under the conditions of wavelength 780 nm, repetition 1 kHz, pulse width 150 fs, energy 870 μJ, and scanning speed 1 mm / s. Four 2 m grooves were formed to form a concave-convex concave-convex concave-convex shape. Thereafter, in the same manner as in Example 1, the light guide was formed by filling the grooves. Further, the end surface of the optical device serving as the light input / output unit was polished by using a polishing apparatus so as to be inclined at 8 °. As polishing conditions, a lapping film manufactured by Sumitomo 3M Co., Ltd. was used, and the polishing liquid was water. The obtained 8 ° end face was confirmed with an optical microscope.

  It was confirmed that two light guides arranged in three dimensions were formed in the thickness direction cross section of the optical device in the thickness direction 2 pieces × width direction 3 pieces = total 6 pieces. The results of the obtained optical device are shown in Table 1.

[Example 4]
Polymethylmethacrylate (type MGSS manufactured by Sumitomo Chemical Co., Ltd.) is added to thermoplastic resin A, and polymethylmethacrylate and polyvinylidene fluoride (Kureha Chemical Co., Ltd. type T850) are added to thermoplastic resin B at a ratio of 8: 2. An alloyed one was used. The extrusion temperature was 240 ° C., the discharge ratio was 5/2, and the protective layer 2 was not formed. Otherwise, an optical device substrate having a thickness of 160 μm was formed in the same manner as in Example 1. Next, using the same excimer laser as in Example 1, two grooves having a depth of 150 μm × width of 50 μm × length of 5 cm were formed at intervals of 100 μm to form concave and convex shapes. Further, a partially fluorinated acrylic low molecular weight compound was poured into the formed groove to obtain a light guide. It was confirmed that two light guides were formed above and below in the thickness direction. The results of the obtained optical device are shown in Table 1.

[Example 5]
MS resin “TX polymer” (methyl methacrylate / styrene) (manufactured by Denki Kagaku Kogyo Co., Ltd.) was used as thermoplastic resin A, and polymethyl methacrylate used in Example 4 was used as thermoplastic resin B. The thermoplastic resins A and B were melted at 250 ° C. in each biaxial vent type extruder, passed through 5 sheets of FSS type leaf disk filters, and then the discharge ratio of the thermoplastic resin A composition / While weighing so that the thermoplastic resin B composition = 2/1, they were joined together by a 9-layer comb-type feed block to obtain a laminate that was alternately laminated in the thickness direction. The breakdown is a laminate having a periodic structure in which four layers of thermoplastic resin A and five layers of thermoplastic resin B are alternately laminated in the thickness direction, and the outermost layer is thermoplastic resin B. (No particles of thermoplastic resins A and B) Further, a thermoplastic resin C obtained by adding 0.02% by weight of agglomerated silica having an average particle diameter of 1.2 μm to the thermoplastic resin B from the third extruder is formed on one side. A two-layer composite pinol under the feed block was joined so as to come to the outermost layer portion to obtain a laminate composed of a total of 10 layers. The cross-sectional shape of the polymer flow path at this time was a square shape having an aspect ratio (length in the width direction / length in the thickness direction) of 2. Moreover, the discharge amount of the laminated resin passing through the cross-sectional area within a unit time was 30 kg / hr / cm ² . After supplying the laminate to a T-die and forming it into a sheet shape, it is calendered using an HCr-plated contact roll whose surface temperature is kept at 25 ° C., rapidly cooled and solidified, and an optical device base that is an unstretched sheet The material was obtained. In addition, the draft ratio at this time was 10, and the obtained sheet | seat thickness was 552 micrometers. Table 1 shows the layer structure.

Next, by cutting with a diamond blade, two grooves having a depth of 500 μm × width of 500 μm × length of 5 cm were formed at intervals of 200 μm, and a convex light guide sandwiched between them was formed. The cutting was performed from the surface not containing particles. Furthermore, the acrylic low molecular weight compound was dissolved in methyl ethyl ketone (MEK), poured into the groove, and dried at a temperature of less than 100 ° C., thereby forming a portion serving as the medium C. It was confirmed that four light guides were formed above and below in the thickness direction. The results of the obtained optical device are shown in Table 1. The formulation of the acrylic medium C coating liquid is shown below.
(I) Foret GS-1000 (Soken Chemical)
(Ii) MEK
(I) / (ii) = 1/1.

[Example 6]
The thermoplastic resin A of Example 4 was charged with 2 wt. Of triazine-based UV absorber 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol. An optical device substrate having a thickness of 331 μm was formed in the same manner as in Example 4 except that the discharge ratio was 1/1 using a 33-layer comb type feed block. Next, using the same excimer laser as in Example 1, three grooves having a depth of 300 μm × width of 50 μm × length of 5 cm were formed at intervals of 50 μm to form a concave / convex concave / convex shape. Further, a partially fluorinated acrylic low molecular weight compound was poured into the formed groove to obtain a light guide. An optical device was fabricated in the same manner as in Example 4 except for this change. It was confirmed that 10 light guide paths arranged in three dimensions were formed in the thickness direction cross section of the optical device in the thickness direction 10 pieces × width direction 2 pieces = total 20 pieces. The results of the obtained optical device are shown in Table 1. Table 1 shows the layer structure and the optical device results obtained.

[Example 7]
1 wt. Of thermoplastic resin A with triazine UV absorber 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy] -phenol. % Added polyethylene terephthalate, and thermoplastic resin B is also triazine-based UV absorber 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-[(hexyl) oxy]- 1 wt. Polycyclohexylene dimethylene terephthalate in which 10 mol of added isophthalate component was copolymerized was used. Thermoplastic resins A and B are both particle-free, melted at 280 ° C. in their respective twin-screw vent type extruders, passed through 5 sheets of FSS type leaf disk filters (filtering accuracy 10 μm), and then into a gear pump. Then, while metering so that the discharge ratio is thermoplastic resin A composition / thermoplastic resin B composition = 3/1, they are merged in a nine-layer comb-type feed block and laminated alternately in the thickness direction. A laminated body was obtained. The breakdown is a laminate having a periodic structure in which four layers of thermoplastic resin A and five layers of thermoplastic resin B are alternately laminated in the thickness direction, and the outermost layer is thermoplastic resin B. The cross-sectional shape of the polymer flow path at this time was a square shape having an aspect ratio (length in the width direction / length in the thickness direction) of 2. Moreover, the discharge amount of the laminated resin passing through the cross-sectional area within a unit time was 10 kg / hr / cm ² . After the laminate is supplied to a T-die and formed into a sheet shape, light is an unstretched sheet which is rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatic applied voltage of 8 kV with a wire. A device substrate was obtained. In addition, the draft ratio at this time was 8, and the obtained sheet | seat thickness was 172 micrometers. Table 1 shows the layer structure.

  Next, using the same excimer laser as in Example 1, three grooves each having a depth of 160 μm × width of 50 μm × length of 10 cm were formed at intervals of 50 μm to form a concave / convex concave / convex shape. (Convex width 50 μm) Next, polyester-based low molecular weight compounds were dissolved in ethyl acetate, poured into the grooves, and dried at a temperature of less than 100 ° C. to obtain medium C, thereby producing an optical device. It was confirmed that four light guides arranged in three dimensions were formed in the thickness direction cross section of the optical device in the thickness direction 4 pieces × width direction 2 pieces = total 8 pieces. Table 1 shows the layer structure and the optical device results obtained.

[Example 8]
Both the thermoplastic resin A and the thermoplastic resin B are not added with a UV absorber, a multi-manifold type feed block is used, and further, the thermoplastic resin A composition / thermoplastic resin B composition = 2/1, In the same manner as in Example 7, an optical device substrate having a sheet thickness of 290 μm was obtained. Table 1 shows the layer structure.

  Next, using the same excimer laser as in Example 1, three grooves each having a depth of 260 μm, a width of 50 μm, and a length of 10 cm were formed at an interval of 50 μm to form a concave / convex concave / convex shape. Next, urethane acrylate-based low molecular weight compounds were dissolved in ethanol, poured into this groove, dried at a temperature of less than 100 ° C., further cured by ultraviolet irradiation, and then dried to obtain medium C to produce an optical device. It was confirmed that three light guide paths arranged in a three-dimensional manner were formed on the cross section in the thickness direction of the optical device: three in the thickness direction × two in the width direction = total six. Table 1 shows the layer structure and the optical device results obtained.

[Example 9]
Polyethylene naphthalate is used as thermoplastic resin A, and polyethylene terephthalate and polyethylene naphthalate are mixed and alloyed at a weight ratio of 3: 7 to thermoplastic resin B. Further, thermoplastic resin A composition / heat An optical device substrate having a sheet thickness of 330 μm was obtained in the same manner as in Example 8, except that the plastic resin B composition = 1.3 / 1. On this base material, an aqueous coating material prepared by adjusting the concentration of colloidal silica particles having a particle size of 80 nm to 3% by weight with respect to the solid component of the vinyl acetate / acrylic resin and melamine resin cross-linking agent using a metabar. Applied. Subsequently, it dried at the temperature of 120 degreeC. Table 1 shows the structure of the obtained layer.

  Next, using the same excimer laser as in Example 1, laser was irradiated from a layer not containing particles to form three grooves of depth 300 μm × width 50 μm × length 10 cm at intervals of 50 μm. A concave shape was formed. Next, an optical device was manufactured using the same medium C as in Example 1. It was confirmed that four light guides arranged in three dimensions were formed in the thickness direction cross section of the optical device in the thickness direction 4 pieces × width direction 2 pieces = total 8 pieces. Table 1 shows the layer structure and the optical device results obtained.

[Example 10]
Polyethylene terephthalate was used for the thermoplastic resin A, and polycyclohexylene dimethyl terephthalate in which 10 mol of an isophthalate component was copolymerized was used for the thermoplastic resin B. Thermoplastic resins A and B are both particle-free, melted at 280 ° C. in their respective twin-screw vent type extruders, passed through 10 sheets of FSS type leaf disk filters (filtration accuracy 5 μm), and then used as gear pumps. Then, weigh it so that the discharge ratio is thermoplastic resin A composition / thermoplastic resin B composition = 4.3 / 1, and merge in a 9-layer comb-type feed block and alternately in the thickness direction. It was set as the laminated body laminated | stacked. The breakdown is a laminate having a periodic structure in which five layers of thermoplastic resin A and four layers of thermoplastic resin B are alternately laminated in the thickness direction, and the outermost layer is thermoplastic resin A. Further, the thickness of the outermost layer was set to ½ that of the inner layer of the thermoplastic resin A. The cross-sectional shape of the polymer flow path at this time was a square shape having an aspect ratio (length in the width direction / length in the thickness direction) of 2. Moreover, the discharge amount of the laminated resin passing through the cross-sectional area within the unit time was 8 kg / hr / cm ² . After the laminate is supplied to a T-die and formed into a sheet shape, light is an unstretched sheet which is rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatic applied voltage of 8 kV with a wire. A device substrate was obtained. In addition, the draft ratio at this time was 8, and the obtained sheet | seat thickness was 292 micrometers. Table 1 shows the layer structure.

Next, in the etching process, a groove having a depth of 250 μm × width 60 μm × length 6 cm is formed at a spacing of 60 μm by milling with a diamond blade having a blade width of 60 μm while keeping the spindle rotation axis parallel to the optical device substrate. 4 were formed to form a convex-concave / concave / convex-concave uneven shape. (Protruding width 60 μm) The inside of the convex portion sandwiched between the grooves becomes the light guide. Next, the substrate was ultrasonically washed with water and dried at 40 ° C. A UV curable resin hard lock OP-1005 (manufactured by Denki Kagaku Kogyo Co., Ltd.) was applied onto the optical device substrate with Metabar # 50, poured into the groove, and the groove was fully buried. Next, after drying at 80 ° C. for 1 minute, UV curing of the coating resin was performed under the condition of irradiation intensity of 120 W / cm ² to obtain medium C, and an optical device was produced. Further, the end surface of the optical device serving as the light input / output unit was polished by using a polishing apparatus so as to be inclined at 8 °. The polishing conditions were a pressure of 0.15 MPa on the polishing disk of the sample, a rotation speed of 240 rpm, a polishing time of 3 minutes, and the polishing liquid was sequentially changed to # 800, 2000, 6000, 8000 using water, Mirror polishing was performed so that the inclination was 8 °. The obtained 8 ° inclined end face was confirmed with an optical microscope.

  It was confirmed that three light guides arranged in three dimensions were formed in the thickness direction cross section of the optical device in the thickness direction 3 pieces × width direction 3 pieces = total 9 pieces. Table 1 shows the layer structure and the optical device results obtained.

[Comparative Example 1]
The polyethylene terephthalate to which the concentration of calcium carbonate having a primary average particle size of 1.1 μm is 0.05% by weight is dried for 3 hours at 180 ° C. Feed and melt at 280 ° C. After high-precision filtration, the sheet is extruded from a coat hanger-type die, extruded, wound around a casting drum at 30 ° C. by an electrostatic application casting method, and cooled and solidified to obtain an optical device substrate that is an unstretched sheet. It was. The draft ratio at this time was 12, and the obtained sheet thickness was 500 μm. Table 1 shows the layer structure.

  Next, using an excimer laser, two grooves of depth 350 μm × width 50 μm × length 5 cm were formed at intervals of 100 μm to form concave and convex shapes. The same polyester low molecular weight compound as in Example 1 was dissolved in ethyl acetate, poured into this groove, and dried at a temperature of less than 100 ° C. to obtain medium C. It was confirmed that the obtained light guide path was tapered and burrs were severe and no light guide path was formed. The results of the obtained optical device are shown in Table 1.

[Comparative Example 2]
It implemented by the method similar to the comparative example 1 except changing a thermoplastic resin into a polybutylene terephthalate. The obtained optical device had a large loss that easily crystallized and caused light scattering. The results are shown in Table 1.

[Comparative Example 3]
Polyethylene terephthalate was used as the thermoplastic resin A, and PET / G (polyethylene terephthalate copolymerized with 20 mol% of cyclohexanedimethanol component) was used as the thermoplastic resin B (thermoplastic resins A and B, both No particles). The thermoplastic resins A and B are melted at 280 ° C. with a single screw extruder of each full flight screw, passed through a wire mesh filter on the mesh, and then discharged at a gear pump with a thermoplastic resin A composition / heat While weighing so that the composition of the plastic resin B = 1/1, it was merged in a 201-layer feed block to obtain a laminate that was alternately laminated in the thickness direction. The breakdown is a laminate having a periodic structure in which the thermoplastic resin A is composed of 101 layers and the thermoplastic resin B is alternately laminated in the thickness direction, and the outermost layer is the thermoplastic resin A. Further, as the protective layer 2 from the third extruder, the thermoplastic resin C obtained by adding 0.02% by weight of agglomerated silica having an average particle size of 1.2 μm to the thermoplastic resin A comes to the outermost layer portion on one side. Were combined from the two-layer composite pinol under the feed block to form a laminate having a total of 202 layers. As the cross-sectional shape of the polymer flow path at this time, a shape having an aspect ratio (length in the width direction / length in the thickness direction) of 2 was used. The laminate was supplied to a T-die and formed into a sheet shape, and then rapidly cooled and solidified on a casting drum maintained at a surface temperature of 25 ° C. while applying an electrostatic application voltage of 8 kV with a wire to obtain an unstretched sheet. .

  This unstretched sheet is longitudinally stretched at 90 ° C. and a stretch ratio of 3.4 times, and both ends are led to a tenter gripped by clips, and 100 ° C. and 4.0 times laterally stretched, and then heat treated at 230 ° C., An optical device having a thickness of 140 μm was obtained without forming the medium C.

  The obtained light guide was widened because there was no optical path restriction in the width direction, and it was confirmed that the light guide was not formed due to scattering / transmission at the interface. The results of the obtained optical device are shown in Table 1.

The present invention relates to an optical device. More specifically, it is an optical device used in the fields of displays, optical sensors, solar cells, optical information communication, and decoration materials, and in particular from optical devices such as multiplexers / demultiplexers and switch elements used in the information communication field. The present invention relates to an optical device suitable for optical interconnection such as optical wiring used for optical mounting.

Cross section of optical device Comb type feed block top view Slit configuration Side view of slit plate in comb type feed block Front view of comb type feed block

Explanation of symbols

1: Thermoplastic resin B
2: Thermoplastic resin A
3: Medium C
4: Light guide 5: Polymer A
6: Polymer B
7: Slit section plate 8: Manifold 9: Feed block 10: Slit section into which polymer A flows in 11: Slit section into which polymer B flows in 12: Short pipe 13: Base 14: Cast drum

Claims (15)

A sheet-like optical device comprising a core and a clad having a refractive index lower than that of the core disposed around the core, wherein the core and a part of the clad are formed of a thermoplastic resin. Is an optical device with multiple light guides. The optical device according to claim 1, wherein a part of the core and the clad are alternately stacked in five or more layers in the thickness direction. The optical device according to claim 1, wherein a plurality of the light guide paths are three-dimensionally arranged in the thickness direction and / or the width direction of the optical device. The optical device according to claim 1, wherein the core has a thickness of 1 μm or more and 300 μm or less, and a thickness of a part of the cladding is 1 μm or more and 500 μm or less. The optical device according to claim 1, comprising a UV absorber. The optical device according to claim 1, wherein the optical device has a length of 1 m or more in the traveling direction of the light guide path. The optical device according to claim 1, wherein a part of the clad is a curable resin. The optical device according to any one of claims 1 to 7, wherein an end face of the optical device is an inclined end face that is inclined by 8 ° with respect to a perpendicular. The optical device according to any one of claims 1 to 8, wherein the elongation at break is 10% or more. The optical device according to claim 1, wherein a wavelength of light used for the optical device is 850 nm. The optical device according to claim 1, which is used in the field of optical information communication modules. A core made of the thermoplastic resin layer A and a part of the clad made of the thermoplastic resin layer B are laminated in three or more layers alternately in the thickness direction by using a laminating device from two extruders, and then from the slit portion of the die A method for producing an optical device, comprising: forming an optical device substrate that is extruded and solidified in a molten state; and a step of forming a light guide path on the optical device substrate. The method of manufacturing an optical device according to claim 12, wherein the step of forming the light guide path on the optical device base material is a laser light irradiation or an etching step using a blade. The method for manufacturing an optical device according to claim 13 or 14, comprising a step of pouring resin into a groove formed by the etching step. The method of manufacturing an optical device according to claim 12, wherein the laser light is an excimer laser.

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