JP5665162B2 - Optical waveguide film and manufacturing method thereof - Google Patents

Description

  The present invention relates to a resin film having a light guide path.

  In recent years, with the explosive increase in communication traffic due to the spread of the Internet, optical fibers and polymers excellent in low noise and high-speed and large-capacity transmission from metal wiring used between and inside devices such as computers and electronic exchanges. It is changing to optical wiring using optical waveguides. In particular, attention has been focused on optical interconnection using a flexible polymer optical waveguide, which is excellent in terms of space saving and weight reduction, and development is being promoted by each company. In particular, this polymer optical waveguide is expected to be developed as an optical interconnection material between boards, boards, chips, and chips.

Examples of a method for producing a polymer optical waveguide include a selective polymerization method, a method combining reactive ion etching (RIE) and photolithography (Patent Document 1), a direct exposure method (Patent Document 2), and an injection molding using a mold. A method based on the law (Patent Document 3), a photo bleaching method (Patent Document 4), and the like are known. However, these manufacturing methods have a problem that the number of steps is very large and the manufacturing time is long, so that the manufacturing cost is high and the production yield is low. In addition, the core / cladding constituting the polymer optical waveguide utilizes a reaction phenomenon of photocuring and thermosetting resin, so that it is difficult to increase the area and length. Furthermore, since these manufacturing methods used physical and chemical etching processes or mold transfer processes when forming the core, irregularities occurred at the interface between the core and the clad, and light compared to plastic optical fibers. There was a problem of increased loss.
On the other hand, as a method for producing a polymer optical waveguide by a melt extrusion method similar to a plastic optical fiber, a method of regularly forming a core in a film width direction using a die has been proposed. (Patent Document 5 and Patent Document 6) Although this manufacturing method can increase the area and length at a low cost, it can be regularly arranged in the film width direction while keeping the core shape constant. It was difficult, and it was difficult to reduce the size of the core.

JP 2004-206016 A JP 2003-185860 A JP 2003-172841 A JP 2004-012635 A Japanese Patent Laid-Open No. 04-043304 JP 05-70571 A

  Compared to the conventional technology, not only can low-cost production be achieved by simplifying the number of processes, but also the fine cores can be arranged regularly and regularly in the film width direction while keeping the core shape constant. In addition, an optical waveguide film having excellent core optical loss characteristics can be provided.

Stretching method in which the lip-cast drum distance (LD) is three times or more of the lip width, which is carried out until it is discharged from the base lip in a molten state into a sheet and reaches the cast drum, and / or Alternatively, after being cooled and solidified by a cast drum, it is an optical waveguide film obtained by a method of stretching between rolls by 1.05 times or more at a melting point or more and a melting point or less of a resin as a core, and a clad as a cross-sectional shape An optical waveguide film having a structure in which four or more cores made of the thermoplastic resin A surrounded by the thermoplastic resin B are arranged in the film width direction while extending in the film longitudinal direction. Is not less than 10 μm and not more than 200 μm, and the crystal melting enthalpy ΔHm of the thermoplastic resin B to be the cladding is 35 J / g or less, and between the core and the cladding Optical waveguide film average roughness Ra of the interface between the core surface is 10nm or less.

  According to the present invention, it is easy to increase the area and length at a low cost, the plurality of core shapes are uniform, and the positions of the cores are regularly and periodically arranged in the film width direction. In addition to facilitating connection, it is possible to provide an optical waveguide film with extremely low optical loss as compared to conventional polymer waveguides. Furthermore, it is possible to provide an optical waveguide film excellent in reliability even under repeated bending and high temperature and high humidity environments. The optical waveguide film of the present invention is suitable for optical communication for medium and short distances of several centimeters to several tens of meters such as between devices, between boards in a device, and between chips in a board.

Width direction (X) -thickness direction (Z) sectional view of an optical waveguide film Width direction (X) -length direction (light traveling direction) (Y) of the optical waveguide film Illustration of core diameter and core spacing Example of cross section and general view of optical waveguide film with irregularities on one side YZ plan view showing an example of feed block XY plan view showing an example of feed block Plan view showing an example of a slit plate Flow chart showing an example of the feed block Sectional view showing an example of a die Perspective view of die with edge guide Sectional view of slit plate for controlling core width and core shape and optical waveguide film obtained by using the slit plate Example of core miniaturization process

In the optical waveguide film of the present invention, the dispersion (core) composed of the thermoplastic resin A serving as a core surrounded by the thermoplastic resin B serving as a clad as a cross-sectional shape extends in the film longitudinal direction while extending in the film longitudinal direction. It is necessary that the optical waveguide film has a structure in which four or more are arranged in each other.
The optical waveguide film of the present invention is an optical waveguide made of a thermoplastic resin and having a core in which light is guided embedded in the film.

  A representative example of a sectional view and an overall view of an optical waveguide film according to the present invention is shown in FIGS. 1 and 2, respectively. FIG. 1 is a cross-sectional view in the width direction (X) -thickness direction (Z) of an optical waveguide film. FIG. 2 is a view in the width direction (X) -length direction (light traveling direction) (Y) of the optical waveguide film. In FIG. 1 (a), the clad wall 2 and the core 3 made of the thermoplastic resin A are regularly arranged in the film width direction in the vicinity of the central portion in the thickness direction, and then the clad layer 1 is on the upper and lower surfaces. A portion constituted by the clad wall 2, the core, and the clad layer 1 becomes an optical waveguide portion. The light travels through the core in the Y direction in FIG. The clad layer 1 and the clad wall 2 are usually preferably made of the same material. In some cases, the clad layer 1 may be omitted. On the other hand, FIG. 1B is an example in which the core interval adjusting unit 4 exists between the cores. The core 3 made of the core interval adjusting unit 4 and the thermoplastic resin A is preferable because it is easy to use the same material, but other types of materials can also be used. In addition, when the core space | interval adjustment part 4 is included in this way, even if the core 3 and the core space | interval adjustment part 4 are the same material, the core space | interval adjustment part 4 is not regarded as a core. This is because the core interval adjusting unit 4 has an excessively large aspect ratio in the thickness direction and the width direction, so that the waveguide performance for optical communication is extremely poor and does not satisfy the light propagation performance as a core. However, when the aspect ratio is 3 or less, it may be regarded as a core. The aspect ratio is an index representing the shape, and is a value obtained by dividing the core width by the core height (core thickness). For example, as shown in FIG. 3A, two parallel lines arranged in the film thickness direction with two parallel lines arranged in the film width direction and a core width 5 that is an interval between the cores (or the core interval adjusting unit) contacting each other. And a value obtained by dividing by the core thickness 6, which is the interval at which the core interval adjusting portion contacts. The core interval adjusting unit can adjust the interval and the core width of the core, and also has an effect of suppressing a change in the core shape in the film width direction. By suppressing the change of the core shape, it also leads to suppression of unevenness of the core width. Furthermore, when assembling the optical waveguide film into the connector, the core interval adjusting portion can be used for dimension adjustment when the center position of the cores arranged in the film width direction is used as a reference. In particular, it is preferable to use the core interval adjusting unit only at both ends in the film width direction. The number is preferably 2 or more and about ½ or less of the number of cores. The core width cannot be adjusted unless there are at least two. Moreover, since there is no meaning when there are too many core space | interval adjustment parts, about 1/2 or less of the number of cores is preferable. As the core width adjustment method, since the width of the discharge port of the die is constant, the core width can be adjusted by controlling the number of cores, the stacking ratio of the core and the cladding wall, and the discharge amount of the core interval adjustment unit. . The discharge amount of the core, the cladding wall, and the core interval adjusting unit can be achieved by adjusting the gap between the slit plate of the feed block in which the core and the cladding and the cladding wall are laminated in the width direction. Generally, it is known that the flow rate of resin flowing out from one slit is proportional to the cube of the slit gap. 11 (a) and 11 (a) are cross-sectional views of a slit plate in the case where there are one core interval adjusting portion 4 at both ends in the film width direction and an optical waveguide film obtained by using the slit plate. b) As shown in (α). The dotted line (α) schematically represents the boundary line 42 in the flow direction of the resin A and the resin B.

  The means for reducing the core width can be adjusted by stretching the optical waveguide film. This is because necking occurs due to stretching. For the stretching, stretching from a molten state performed until the glass core is discharged from the die and cooled, and once cooled and solidified by a casting drum, the glass transition point of the resin constituting the core of the optical waveguide film + 20 ° C. or higher There are two ways of stretching. The former method is preferably used in order to achieve the fineness of the core width of 1/10 or less from directly below the base. However, the stretching is accompanied by a change in the core thickness. The core thickness can be adjusted by the die lip gap and the casting speed.

  In addition, in order to suppress the change in the core shape in the film width direction, it is preferable to use two or more core interval adjusting portions to narrow the width in order from the end toward the center portion. This is because the deformation of the core shape is suppressed because the adjacent laminar flow velocities immediately after coming out of the slit plate in the laminating apparatus are aligned. 11 (a) and (β) are cross-sectional views of a slit plate in the case where there are four core spacing adjusting portions 4 at both ends in the film width direction, and an optical waveguide film obtained by using the slit plates. b) As shown in (β).

The optical waveguide film of the present invention must contain 4 or more cores. From the viewpoint of high-speed and large-capacity optical transmission, the number is preferably 16 or more. More preferably, it is 32 or more. More preferably, it is 64 or more. The number of cores is preferably expressed by 2 ⁿ (n is a natural number of 2 or more) from the viewpoint of being used for information communication. The larger the number of cores, the higher the density of optical wiring that enables communication with more channels, and the more efficient optical transmission becomes possible. The upper limit of the number of cores is not particularly limited, but is preferably 3000 or less in order to maintain practical characteristics. The number of cores can be easily achieved by adjusting the number of cores and clad walls stacked in the stacking apparatus (feed block). Moreover, it is preferable that the length of a core is at least 1 cm or more from a viewpoint used for the communication use for short-medium distances. More preferably, it is 10 cm or more. Most preferably, it is wound into a roll with a length of several tens to several hundreds of meters so that only a necessary length can be taken out and used.

The core shape depends on the core diameter because of the number of modes, but may be any geometric figure such as a circle, an ellipse, a square, a trapezoid, or a star. When used for information communication applications, from the viewpoint of mode dispersion depending on the core shape, it is preferable that the figure is as symmetric as possible, and the most preferable shape is a circle. Then it is square and trapezoid. Symmetry includes line symmetry and point symmetry. In the present invention, it tends to be a quadrangle, and in that case, the eccentricity of the core is preferably 0.6 or more, more preferably 0.8 or more from the viewpoint of high-speed information communication. The eccentricity is a value obtained by dividing the area of the core by the area of the circumscribed rectangle of the core. The achievement method depends on the combination of the rheology of the core and the clad, but from the viewpoint of reducing the stress at the interface between the core and the clad due to the melt viscosity difference between the core and the clad, the melt viscosity difference at the core and clad extrusion temperature is It is preferably 1900 poise or less at a shear rate of 100 S ^ (-1). Further, stretching between the die and the cast is also preferable because the core shape distorted inside the die is relaxed. The core diameter is not less than 10μm from the viewpoint of too small amount of light becomes easier, whereas, from the standpoint of confinement of light in too large the core is difficult, it is 5mm or less. More preferably, it is 20 μm or more and 1 mm or less. In particular, when used for information communication applications, it is preferably 20 μm or more and 200 μm or less from the viewpoint of multimode compatibility. More preferably, they are 30 micrometers or more and 100 micrometers or less. As shown in FIG. 3 (a), the core diameter here refers to two parallel lines aligned in the film thickness direction and a core thickness 6 that is an interval between the core and the two parallel lines aligned in the film width direction and the core. It is the average value of the length of the core width 5 which is the space | interval which contacts.

  In the present invention, the direction of four or more cores (light traveling direction) is substantially parallel, and the center positions of the four or more cores are arranged substantially parallel to the film surface. preferable. That is, it is preferable that the cores are linearly arranged at equal intervals in the film width direction. In such a case, high-density wiring is possible, light input / output adjustment is easy, and the time for optical connection work can be greatly reduced.

The thermoplastic resin constituting the optical waveguide film of the present invention is a copolymer having polymethyl methacrylate (refractive index n is 1.49, hereinafter refractive index is n) and methyl methacrylate as main components (n = 1.47 to 1.50), for example, methacrylate / styrene copolymer (n = 1.53), methacrylate / butadiene / styrene copolymer (n = 1.58), polystyrene (n = 1.58) and styrene as main components (N = 1.50 to 1.58), for example, styrene / butadiene copolymer (n = 1.57 to 1.58), acrylonitrile / styrene / butadiene copolymer (n = 1.51 to 1.54), polyethylene (n = 1.51 to 1.54), polyvinyl chloride (n = 1.54), polypropylene (n = 1.47 to 1.52), polylactic acid n = 1.47), norbornene-based alicyclic olefin (n = 1.51 to 1.53), styrene acrylonitrile copolymer (n = 1.56), poly-4-methylpentene 1 (n = 1.46 to 1.47), polyvinyl alcohol (n = 1.49 to 1.53), ethylene / vinyl acetate copolymer (n = 1,46 to 1.50), nylon 6,11,12,66 (n = 1.53) ), Polycarbonate (n = 1.50-1.57), polyethylene terephthalate (n = 1.58-1.68), polyethylene terephthalate copolymer (n = 1.54-1.66), fluorene copolymerized polyethylene terephthalate ( n = 1.6-1.66), polyethylene naphthalate (n = 1.65-1.81), polychlorostyrene (n = 1.61), polyvinylidene chloride ( = 1.63), polyvinyl acetate (n = 1.47), methyl methacrylate / styrene, vinyl toluene or α-methylstyrene / maleic anhydride terpolymer or quaternary copolymer (n = 1.50-1) .58), polydimethylsiloxane (n = 1.40), polyacetal (n = 1.48), polyethersulfone (n = 1.65 to 1.66), polyphenylene sulfide (n = 1.6-1) .70), polyimide (n = 1.56 to 1.60), fluorinated polyimide (n = 1.51 to 1.57), polytetrafluoroethylene (n = 1.35), polyvinylidene fluoride (n = 1.42), polytrifluoroethylene (n = 1.40), perfluoropropylene (n = 1.34), tetrafluoroethylene-perfluoroalkyl vinyl ether Copolymer (n = 1.36 to 1.4), tetrafluoroethylene-hexafluoropropylene copolymer (n = 1.36 to 1.4), tetrafluoroethylene-ethylene copolymer (n = 1. 36 to 1.4), polychlorotrifluoroethylene, and binary or ternary copolymers of these fluorinated ethylenes (n = 1.35 to 1.40), polyvinylidene fluoride and polymethylmethacrylate blend polymer _{(n = 1.42~1.46), CF 2} = CF-O- (CF 2) a polymer of x -CF = CF ₂ monomer (n = 1.34) and fluorinated ethylene copolymer (n = 1 _{.31~1.34), CF 2 = CF-} O- (CF 2) -O-CF = CF 2 monomers of the polymer (n = 1.31) and fluorinated copolymers of ethylene (n = 1.31~ 1. 4), the general formula _CH 2 ₌ C (CH 3) a copolymer mainly containing fluorinated methacrylate represented by COORf, group Rf is _{(CH 2) l (CF 2} ) mH in which copolymer (n = 1.37 1.42), Rf is (CH ₂ ) _m (CF ₂ ) ₁ F (n = 1.37 to 1.40), Rf is CH · (CF ₃ ) ₂ (n = 1.38) ), Rf is C (CF ₃ ) ₃ (n = 1.36), Rf is CH ₂ CF ₂ CHFCF ₃ (n = 1.40), Rf is CH ₂ CF (CF ₃ ) ₂ (N = 1.37), and copolymers of these fluorinated methacrylates (n = 1.36-1.40), and their fluorinated methacrylate and methyl methacrylate copolymers (n = 1.37-1.43), General formula CH ₂ = CH · COORf A polymer mainly composed of a fluorinated acrylate represented by ', wherein Rf' is (CH ₂ ) _m (CF ₂ ) _l F (n = 1.37 to 1.40), and Rf 'is (CH ₂ ). _m (CF ₂ ) ₁ H (n = 1.37 to 1.41), Rf ′ is CH ₂ CF ₂ CHF · CF ₃ (n = 1.41), Rf ′ is CH (CH ₃ ) ₂ (n = 1.38), and their fluorinated acrylate copolymers (n = 1.36 to 1.41), and these fluorinated acrylates and said fluorinated methacrylate copolymers (n = 1.36 to 1.41) ), and port mainly composed of 2-fluoroacrylate represented by these fluoride acrylates and fluorinated methacrylates and methyl main crate copolymer (n = from 1.37 to 1.43), the general formula _CH 2 = CF · COORf " Ma, and copolymers thereof (n = 1.37~1.42) (where, wherein Rf "is _{CH 3, (CH 2) m} (CF 2) l F, (CH 2) m (CF 2) l H , CH ₂ CF ₂ CHFCF ₃ , and C (CF ₃ ) ₃ ). Typical fluorinated polymethacrylates include fluorine such as 1,1,1,2,3,3-hexafluorobutyl methacrylate polymer, trifluoroethyl methacrylate polymer, hexafluoropropyl methacrylate polymer, and fluoroalkyl methacrylate polymer. Polymethyl methacrylate copolymer contained (n = 1.38 to 1.42). L, m, and x are each independently preferably a positive integer of 2 to 16.

  n represents a refractive index at a wavelength of 590 nm. From the viewpoint of guiding light, the refractive index of the thermoplastic resin A serving as the core needs to be larger than that of the thermoplastic resin B serving as the cladding. From the viewpoint of reducing the bending loss of light, the numerical aperture NA is preferably 0.4 or more. More preferably, it is 0.6 or more. The numerical aperture is represented by the square root of the value obtained by subtracting the square of the refractive index of the cladding from the square of the refractive index of the core.

  These resins may be a resin composed of one type of repeating unit, or may be a copolymer or a mixture of two or more types of resins. Among these, from the viewpoint of strength, heat resistance, transparency, and low loss, the thermoplastic resin A is polycarbonate, polymethyl methacrylate, alicyclic olefin, polystyrene, polyimide resin, polyethylene terephthalate, polyethylene naphthalate, and These copolymers, thermoplastic resin B, are poly (4-methylpentene-1), ethylene propylene copolymer, polyethylene terephthalate, polyethylene, nylon 6, nylon 12, nylon 66, fluorinated polymer, and copolymers thereof. A polymer is preferred. Moreover, it is more preferable that the hydrogen atom of the thermoplastic resin used as a core is deuterated from a viewpoint of reducing the optical loss in light wavelength 1310nm and 1550nm. Further, as a role of protecting the optical waveguide film of the present invention, it is preferable that the outer side of the cladding layer is coated with nylon, vinyl chloride, or polyethylene. Of these, nylon and crosslinked polyethylene are most preferred from the viewpoint of heat resistance. Various additives such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, thinning agents, thermal stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, for refractive index adjustment A dopant or the like may be added to the thermoplastic resin.

  When 90 wt% or more of the optical waveguide film of the present invention is made of a thermoplastic resin, surface processing such as laser processing, diamond knife processing, and thermal compression processing is facilitated. Connection of light between chips is further facilitated, and a low-cost optical information transmission system can be provided.

The average roughness Ra of the core surface at the interface between the core and the clad of the optical waveguide film according to the present invention needs to be 100 nm or less. When the average roughness Ra of the core is 100 nm or more, light scattering increases, and thus the light loss increases. The average roughness Ra of the core is 10 nm or less. In addition to depending on the absorption characteristics of the core material, the present invention can be achieved by a manufacturing method in which the core and the clad are formed by the melt extrusion method. More effectively, it can be achieved by appropriately adjusting the resin properties on the core and clad sides. Resin properties are melt viscosity and crystallinity. Specifically, from the viewpoint of reducing the stress at the interface between the core and the clad due to the melt viscosity difference between the core and the clad, the melt viscosity difference at the extrusion temperature of the core and the clad is 5000 poise or less for a shear rate of 100 S ^ (-1). It is preferable that More preferably, it is 2000 poise or less, and still more preferably, 1000 poise or less. The melt viscosity can be measured using a known flow tester. In addition, it is a well-known fact that an amorphous polymer is used for the core material, but it is preferable to use a polymer having low crystallinity in the cladding material, and thus an amorphous polymer. Since protrusions due to residual foreign matters such as gels and contaminants are generated at the core-cladding interface, it is preferable to remove them by increasing the accuracy of the vacuum vent and filter. Furthermore, it is preferable that the surface roughness of the wall surface of the polymer channel is 0.8 S or less from the viewpoint of the resin flowing without being disturbed in the channel. By doing so, the surface roughness of the core is reduced. More preferably, it is 0.2S or less.

  A more effective achievement method is achieved by stretching the optical waveguide film of the present invention. As the stretching method, the optical waveguide film of the present invention is discharged from the base lip in a molten state and reaches the casting drum to be cooled and solidified, and the casting drum is once cooled and then thermoplastic. There is an inter-roll stretching method in which stretching is performed at the glass transition point Tg + 20 ° C. of the resin A or B. The former stretching direction is the longitudinal direction. Since the interface between the core and the clad is smoothed by stretching, an average roughness Ra of 20 nm or less of the core surface can be easily achieved. Even if the clad is a crystalline resin, the core surface is kept smooth because it is microcrystallized by stretching orientation. Further, even after the heating test, the smoothness of the core surface is maintained without roughening the interface between the core and the clad. In the former method, since the core is uniaxially stretched in the former method, the stretching ratio is adjusted by the LD (lip-cast drum) distance and draft ratio according to the desired core size. The distance between the LDs is preferably 3 times or more, more preferably 5 times or more of the lip width from the viewpoint of stretching from the molten state. The draft ratio is preferably 10 or more, more preferably 30 or more. The draft ratio here is a value obtained by dividing the lip gap by the thickness of the optical waveguide film. Unlike the common knowledge of film casting, a film-forming method similar to such melt spinning makes it easy to produce a fine core with an extremely low average roughness of the core surface and a core width of 50 μm or less. Can be obtained. On the other hand, since the latter method is not in a molten state, the uniformity of the core shape may be lost in the film width direction due to stretching, or birefringence may occur, so 1.05 to 3 times is preferable. . More preferably, it is 1.1 times or more and 2 times or less. In order to miniaturize the core, it is most effective to combine these methods.

Moreover, it is preferable that the maximum height Rmax of the core surface at the boundary surface between the core and the clad of the optical waveguide film of the present invention is 200 nm or less. When the maximum height Rmax exceeds 200 nm, light scattering increases, so that light loss increases. More preferably, it is about 1/10 or less of the wavelength of the light used, and 80 nm or less is preferable from the viewpoint of suppressing light scattering. The core surface may be a core surface adjacent to the cladding layer or a core surface adjacent to the cladding wall. As a method for achieving this, it can be achieved by a method similar to the method for reducing the average roughness of the core surface, or a method for cutting foreign matters or metal catalysts that become coarse protrusions through a filter. Here, Ra and Rmax are centerline average roughness and maximum roughness, respectively. Ra takes a measurement length L portion from the roughness curve in the direction of the center, the extraction center line is X-axis, the vertical axis is Y, and the roughness curve is represented by Y = f (x). It is given by the following equation (1).
_{^{Ra = 1 / L∫ L 0 |}} f (x) | dx ··· (1) equation addition, Rmax represents the distance of the largest peaks and the deepest valley in the roughness within the measuring length of the curve. These values can be obtained by a method using the tip of the needle or a non-contact measurement method using light. For example, the former includes a contact type three-dimensional surface roughness meter and a non-contact type scanning probe microscope (SPM). As the SPM, there are a scanning tunnel microscope (STM), an atomic force microscope (AFM), and a scanning near-field optical microscope (SNOM), and these can be used for measurement. On the other hand, the latter can measure surface roughness by two-dimensional and three-dimensional image processing from observation images with a laser microscope and various optical microscopes. Another non-destructive method for measuring the roughness of the core surface at the core-cladding interface is the Vertical Scanning Interferometry (VSI). This is because when white light with a short coherence distance is used as the light source and the Z axis of the microscope is vertically scanned, the modulation of the interference fringes is maximized when the distance between the measurement optical path and the reference optical path matches. By utilizing this principle, even if the measurement is usually performed only on the clad side which is the surface of the optical waveguide film, the average roughness of the core surface which hits the back surface of the clad can be measured. As this apparatus, for example, there is a thin film corresponding surface shape measuring apparatus SP-700 manufactured by Toray Engineering.

Crystal melting enthalpy ΔHm of the thermoplastic resin B as the cladding of the optical waveguide film of the present invention, Ru Der below 35 J / g. If it is 35 J / g or more, unevenness due to crystallization is likely to occur on the clad side of the interface between the core and the clad, and light scattering increases. Therefore, the optical loss increases. More preferably, it is 20 J / g or less. More preferably, it is 10 J / g or less. Most preferably, it is achieved by using an amorphous polymer that has no crystalline melting peak. Examples of a method for reducing the crystal melting enthalpy ΔHm of a crystalline or semicrystalline polymer include alloying of different materials. By alloying, the brittleness of the crystalline polymer can be improved. For example, when nylon 6 and polypropylene are alloyed using carboxylic acid-modified polypropylene as a compatibilizing agent, the crystallinity of nylon 6 and polypropylene, which are inherently crystalline, decreases. From the viewpoint of improving heat resistance and high temperature and high humidity resistance, the blending ratio is 5 to 35 parts by weight of nylon 6, 65 to 95 parts by weight of polypropylene, and 1 to 10 parts by weight of carboxylic acid-modified polypropylene. Can reduce the ΔHm of the original polypropylene. These can be measured using DSC or μTMA.

  The crystal grain size of the thermoplastic resin B serving as the cladding of the optical waveguide film of the present invention is preferably 20 nm or less. When the crystal grain size is 20 nm or more, irregularities are likely to occur on the core side of the core / cladding interface, and light scattering increases. Therefore, the optical loss increases. More preferably, it is 10 nm or less. The crystal grain size here is a value obtained based on Scherrer's equation from the half width of the diffraction peak obtained by X diffraction measurement. These achievement methods can be achieved by selecting a resin to be a clad, polymer alloy of the clad resin, adjusting a crystal nucleating agent, and optimizing manufacturing process conditions.

  The clad is preferably made of a thermoplastic resin B containing a molecular skeleton or a functional group having the same composition as the core made of the thermoplastic resin A of the optical waveguide film of the present invention. Here, the molecular skeleton is a repeating unit constituting a resin. For example, when one resin is polyethylene terephthalate, ethylene and terephthalate are molecular skeletons. As another example, when one resin is polyethylene, ethylene is a molecular skeleton.

  Functional groups are ether groups, hydroxy groups, ketone groups, carboxyl groups (carboxylic acids), aldehyde groups, amide groups, sulfo groups, and the like. When the thermoplastic resin A and the thermoplastic resin B are resins containing the same molecular skeleton or functional group, the interface between the core and the clad has good compatibility, and peeling at the interface (interlayer) is less likely to occur.

  The optical waveguide film of the present invention preferably comprises a carboxylic anhydride-modified polyolefin. It may be contained in the core and / or the clad. Due to the surfactant action of the carboxylic anhydride, the interface between the core and the clad is compatible, and peeling between the core and the clad is difficult to occur. Carboxylic anhydride is a compound (R—CO—O—CO—R ′) obtained by dehydration condensation of two molecules of carboxylic acid. As the carboxylic anhydride, maleic anhydride is most preferable. From the viewpoint of not reducing the optical loss of the core, it is preferably contained in the clad. More preferably, the clad is a thermoplastic resin composed of a polyolefin and a modified polyolefin containing carboxylic anhydride. The polyolefin is preferably a homopolymer or copolymer of polypropylene, polyethylene, or cycloolefin. As the core in this case, a copolymer such as cycloolefin polymer, polycarbonate homo, polyester, and nylon is preferable.

  It is preferable that a 45 degree mirror is included in the light guide of the optical waveguide film of the present invention. The 45-degree mirror here means that there is a cut having an inclined surface of 45 degrees with respect to the direction (Y) in which the core extends. A 45-degree inclined surface can be achieved by cutting with a diamond knife or the like, or laser ablation. As the laser, any laser such as an excimer laser, a YAG laser, a carbon dioxide gas laser, or a femtosecond laser may be used. As a laser selection method, in the case of a core material that absorbs ultraviolet rays, an excimer laser or a YAG laser having a wavelength of 266 nm using a fourth harmonic is preferable. The core material can be accurately processed by an excimer laser by adding a material having a benzene ring, such as polyester, or an ultraviolet absorber. In the excimer laser, since the beam shape is a rectangular wave, it can be achieved by focusing and obliquely incident on the core of the workpiece, while the YAG laser has a Gaussian beam shape. An inclined surface of a degree can be formed. At this time, it is preferable to use nitrogen, oxygen, argon, helium or the like as the assist gas from the viewpoint of preventing generation of foreign matter. As the post-treatment, it is preferable to slightly melt the surface after cutting or laser processing using a carbon dioxide laser because a smooth surface can be obtained. By obtaining such a mirror, the optical path can be changed at a right angle, so that it becomes easy to easily connect the PD or VCSEL of the board and the optical waveguide film.

  In all the film width directions of the optical waveguide film of the present invention, the core width unevenness is preferably 10% or less. More preferably, it is 5% or less. Here, the core width 5 indicates an interval at which the core contacts two parallel lines arranged in the film width direction as shown in FIG. The unevenness of the core width is a value obtained by dividing the maximum and minimum difference between the core widths in all the film width directions by the core width in the center in the film width direction and multiplying by 100. Moreover, it is preferable that the nonuniformity of the core interval is 10% or less in all the film width directions of the optical waveguide film of the present invention. More preferably, it is 5% or less. Here, the core interval 7 is a distance connecting the midpoints of the core widths of adjacent cores as shown in FIG. The unevenness of the core interval is a value obtained by dividing the maximum and minimum difference between the core intervals in all the film width directions by the average core interval and multiplying by 100. The method of achieving them is to optimize the viscoelastic properties of the resin. Specifically, the stress at the interface between the core and the clad due to the difference in melt viscosity between the core and the clad is reduced, and the core shape in the film width direction is reduced. From the viewpoint of suppressing deformation, the melt viscosity difference at the extrusion temperature of the core and the clad is preferably 5000 poise or less for a shear rate of 100 S ^ (-1). More preferably, it is 2000 poise or less, and still more preferably, 1000 poise or less. However, this is not the case because the core shape changes depending on the elastic term of the resin. Further, in order to suppress a change in the core shape that occurs near the end in the film width direction due to neck-down, it is preferable to provide a core interval adjusting portion as a buffer material at both ends in the film width direction. The flow rate of one core interval adjusting unit is preferably 5 times or more the flow rate of one core. The number is preferably 2 or more. If the difference in flow velocity between the adjacent cladding wall of the core interval adjusting portion and the next adjacent core is large, the core shape is deformed. From the viewpoint of adjusting the flow rate, it is preferable to gradually adjust the flow rate to the core from the end using six or more core interval adjusting units. The slit plate of the example of eight core interval adjusting parts and the structure of the obtained optical waveguide film cross section are shown in FIGS. 11 (a), (β) and (b), (β), respectively.

  According to the present invention, from the viewpoint of facilitating optical connection, it is an optical waveguide film that extends in the film longitudinal direction while a concavo-convex structure that becomes valleys and ridges periodically exists in the film width direction on at least one film surface. Preferably there is.

  An example of this schematic diagram is shown in FIG. When the clad portions located between the cores are depressed, the clad portions existing between the cores in the longitudinal direction of the film become concaves that are valleys, and the cores are convex that are ridges. Is present. (The depressed portion may be a core portion.) The uneven structure extends in the film longitudinal direction while periodically existing on the film surface in the film width direction. The unevenness difference is preferably 3 μm or more. The unevenness difference 10 is a difference between the maximum point and the minimum point of the adjacent ridge 8 and valley 9 respectively. This is indicated by 10 in FIG. In this invention, the uneven | corrugated difference of the core vicinity of a film width direction center part is employ | adopted among several unevenness | corrugations. By using the unevenness as a guide when connecting the connector, accurate alignment is possible. When the unevenness difference is smaller than 3 μm, it becomes difficult to use as a guide for connector connection. More preferably, it is 20 μm or more. In addition, if the unevenness difference is too large, the supportability is lost, and therefore it is preferably less than half the core thickness. In this invention, it becomes possible to cut | disconnect a film simply and correctly by setting a recessed part as a guide at the time of film cutting. The uneven structure may exist on both sides of the film. This can be achieved by the difference in extrusion temperature, viscoelastic properties, and extrusion amount of the core and clad. It is also preferable to use an amorphous resin for the core and a crystalline resin for the cladding wall.

  The optical waveguide film of the present invention preferably has a light loss change amount of 0.5 dB or less after a heat resistance test at 85 ° C. for 1000 hours. This is because it becomes difficult to correctly receive the transmitted optical signal when the optical loss change amount exceeds 0.5 dB. More preferably, it is 0.3 dB or less. This is achieved by setting the glass transition point (Tg) of the core material to 90 ° C. or higher. More preferably, it is 130 ° C. or higher. Examples of the core material having a Tg of 90 ° C. or higher include fluorene copolymerized polyethylene terephthalate, polymethyl methacrylate, and polystyrene. Above 120 ° C., a polyethylene naphthalate copolymer, a cycloolefin copolymer, a cycloolefin polymer, and a polycarbonate are preferable. As the cladding material, fluoropolymer, polypropylene, ethylene propylene copolymer, and nylon 6 are preferable from the viewpoint of hardly causing thermal degradation. Further, orientation imparting by stretching and then heat treatment at 90 ° C. or higher are also preferable from the viewpoint of imparting heat resistance.

  Next, the optical waveguide film of the present invention preferably has a light loss change amount of 0.5 dB or less after a high temperature and high humidity test of 1000 hours at 70 ° C./90% RH. More preferably, it is 0.3 dB or less. The achievement method can be achieved by selecting a material having low heat resistance and low hygroscopicity as the core material. In addition, the cladding material can be achieved by selecting a gas barrier material. From the viewpoint of heat resistance, the core material preferably has a glass transition point of 90 ° C. or higher, and more preferably 130 ° C. or higher. As the core material having low hygroscopicity, a cycloolefin copolymer and a cycloolefin polymer are preferable. As the cladding material, polyethylene, polypropylene, nylon, and alloys and copolymers thereof are preferable.

  The optical waveguide film of the present invention preferably has a light loss change amount of 0.5 dB or less after a repeated bending test at R = 3 mm. From the viewpoint of imparting toughness to the core, this is achieved by setting the draw ratio of the core to 1.3 times or more. More preferably, it is twice or more. More preferably, it is 3 times or more.

  When the optical waveguide film of the present invention is used for communication, the wavelength of light is preferably in the visible to near infrared ray region (400 nm to 1550 nm). In particular, it is preferably 1200 nm or less. Usually, the wavelength used for long-distance optical communication is in the near infrared region such as 1.55 μm and 1.31 μm. However, in the present invention, since the thermoplastic resin is used, in general, the near infrared region described above is used. Often have a light absorption edge. Therefore, a wavelength of 600 to 1100 nm having a feature of low light absorption and a large transmission capacity is preferable, and it is particularly preferable for the optical waveguide film of the present invention to use light having a wavelength of 1000 nm, 850 nm, or 650 nm.

Further, it is important that the optical waveguide film of the present invention has a low propagation loss in order to guide light as far as possible. Since optical propagation loss is low, accurate optical information can be transmitted far away. Therefore, Preferably, it is 0.25 dB / cm or less. More preferably, it is 0.1 dB / cm or less. More preferably, it is 0.05 dB / cm or less. Selection of thermoplastic resin such as polymethyl methacrylate, cycloolefin copolymer, polycarbonate, etc. with low light scattering and absorption loss, core shape and core size with good symmetry are formed, and the average roughness of the core surface at the core / cladding interface is 50 nm Hereinafter, the maximum height can be 100 nm or less, and can be achieved by optimizing the manufacturing process.
The optical module using the optical waveguide film of the present invention is a system in which optical I / O is incorporated. The optical module is an electronic component that generally converts light and electricity into each other. For example, a system having a basic configuration of a surface emitting semiconductor laser (VCSEL) that is a light transmitting side, an optical waveguide film that is a polymer optical waveguide, and a photodiode that receives light. More specifically, for example, this configuration is an optical backplane for connection between devices such as routers and servers, between boards, connection between a display unit of a mobile phone and a CPU, and a memory on a printed circuit board such as a high-end personal computer. -A system mounted on the connection between the control and drive of the CPU connection, the switch LSI package, and the car navigation system.

  The optical waveguide film of the present invention can be used for applications such as display members, solar cell members, decorative members, illumination members, and information communication members. When the optical waveguide film is irradiated with light from the direction perpendicular to the film surface, anisotropic diffusion or diffraction phenomenon occurs depending on the core interval, so that the light spreads in a specific direction. Therefore, it can be used as an anisotropic diffusion plate, a viewing angle control film, a polarizing film or the like of LCD as a display member. Moreover, when using as an optical waveguide which puts light in a surface, it can utilize as a light-guide plate. Furthermore, the above effects can be further achieved by further adding embossing, coating with high-concentration particles, and the like to the surface of the optical waveguide film of the present invention. In particular, when utilizing light guide performance, it can be used as an edge-ride type light guide plate of an LCD backlight. By combining with a lens or the like, the light can be efficiently collected in the waveguide, and therefore can be used as a solar cell member that requires photoelectric conversion. For example, the core and the Fresnel lens can be joined, the sunlight can be collected, and the light can be guided to the solar battery cell with the optical waveguide film. By setting the color of the light source to be guided to red, blue, yellow, and green, it can be used for design applications such as signboards. Moreover, it can also be used as an illumination member by collecting light such as a laser, a halogen lamp, a white LED, and sunlight, guiding the light to a target position with an optical waveguide film, and irradiating it. In particular, it can be used as indirect lighting for exhibits such as artworks that dislike the heat and ultraviolet rays from the light source, and in-room room lamps. In particular, the optical waveguide film of the present invention can be suitably used for short-to-medium / long-distance optical waveguides such as inter-device communication and intra-device communication.

Therefore, the optical waveguide film of the present invention is preferably used for lighting devices, communication devices, and display devices. Moreover, it is also preferable to be used as a light guide with a connector. As a connector standard, it is preferable to use an MT connector, an MPO connector, an MPX connector, a PMT connector, a PT optical connector, etc. from the viewpoint of versatility of a multi-core type.
In addition, the optical waveguide film of the present invention can be used as an image guide and an optical sensor synthesizing member. The light source may be a VCSEL, LD, or LED.

Next, the preferable manufacturing method of the optical waveguide film of this invention is demonstrated below.
Two types of thermoplastic resins A and B are prepared in the form of pellets. In order to further reduce the loss, it is preferable that the thermoplastic resin polymerization system and the film forming system are closed systems. In this case, it is not always necessary to be a pellet. The pellets are supplied to the extruder after pre-drying in hot air or under vacuum as necessary. In the extruder, the thermoplastic resin that has been heated and melted is made uniform in the extrusion amount of the thermoplastic resin by a gear pump or the like, and foreign substances, denatured thermoplastic resin, and the like are removed through a filter or the like.

  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. For example, when alloying, a single screw screw is preferably a dalmage type or a Maddox type, and a biaxial screw is preferably a screw structure in which kneading is strengthened by a combination of paddles. On the other hand, when extruding one kind of thermoplastic resin from one extruder, if the kneading is too strong, foreign matter that causes light loss is generated, so a single shaft using a full flight screw or double flight is used. An extruder is preferred. The L / D of the screw is preferably 28 or less, and more preferably 24 or less. Moreover, it is preferable that the compression ratio of a screw is 3 or less, More preferably, it is 2.5 or less. In addition, as a method for removing foreign matters that cause light loss, it is effective to use a known technique such as vacuum vent extrusion or a filtration filter. The pressure of the vacuum vent is preferably about 1 to 300 mmHg in terms of differential pressure. Further, as the filter, high-precision filtration can be performed by using an FSS (Fiber Sintered Stereo) leaf disk filter during melt extrusion. Although it is preferable to appropriately change the filtration accuracy of the filter depending on the generation state of the size and amount of foreign matter and the filtration pressure due to the resin viscosity, it is preferable to use a filtration accuracy filter of 10 μm or less in the present invention. More preferably, it is 5 micrometers or less, More preferably, it is 2 micrometers or less. Further, the resin pressure at the tip of the extruder at that time is preferably 10 MPa or less, more preferably 5 MPa or less, from the viewpoint of reducing resin leakage.

  The thermoplastic resin delivered from different flow paths using these two or more extruders is then fed into a pinol-integrated feed block. An example of a preferred pinole-integrated feed block of the present invention is shown in FIG. FIG. 5 is a plan view of a pinole-integrated feed block. The pinole-integrated feed block 11 includes side plates 12 and 13 for supplying a resin B serving as a cladding layer, a resin reservoir 14 for the resin B serving as the cladding layer, and a resin B liquid reservoir serving as the cladding layer. The A supply unit 15, the slit plate 16, the resin B supply unit 17 having a resin B liquid reservoir serving as a clad layer, and the resin B liquid reservoir 18 serving as a clad layer are integrated and used. 5 and 6 is derived from a resin A supply unit 15 having a resin B liquid reservoir serving as a clad layer, and a resin B supply unit 17 having a resin B liquid reservoir serving as a clad layer. And two resin inlets 20 and one resin inlet 33 for forming a cladding layer. Here, the types of the resin introduced into the plurality of slits existing in the slit plate 16 are the resin A supply unit 15 having the resin B liquid reservoir part serving as the cladding layer and the resin B liquid reservoir part serving as the cladding layer. It is determined by the positional relationship between the resin B supply unit 17 and the bottom of each liquid reservoir 21 and the end of each slit in each slit plate. The mechanism will be described below.

  FIG. 7A is an enlarged view of the slit portion 16. A p-p ′ cross section showing the shape of the slit 23 a is (b) in the figure, and a q-q ′ cross section showing the shape of the slit 23 b is (c) in the figure. As shown in (b) and (c), the ridge line 26 of each slit is inclined with respect to the thickness direction of the slit plate.

  In FIG. 8, the resin A supply part 15 which has the liquid reservoir part of resin B used as a clad layer, the slit part 16, and the resin B supply part which also has the liquid reservoir part of resin B used as a clad layer among pinol integrated feed blocks. 17 is shown. Then, a resin A supply unit 15 having a resin B liquid reservoir part serving as a clad layer, a resin B supply unit 17 having a resin B liquid reservoir part serving as a clad layer, and the heights of the bottom surfaces 32 and 30 of the liquid reservoirs in each of them. The height is located between the upper end portion 28 and the lower end portion 27 of the ridge line 29 existing in the slit portion. As a result, resin is introduced from the liquid reservoir 32 from the side where the ridgeline 29 is high (arrow 31 in FIG. 8), but the slit is sealed from the side where the ridgeline 29 is low and the resin is introduced. Not.

  Although not shown, in the slit adjacent to the slit noted in FIG. 8, the ridgeline of the slit is arranged at an angle opposite to that in FIG. The portion 17 is introduced into the slit plate 16. Thus, since the resin A or the resin B is selectively introduced for each slit, if the resin B is a clad forming material and the resin A is a core forming material and / or a core interval adjusting portion, a plurality of cores and clad walls are formed. A resin flow having an arrayed structure is formed in the slit plate 16 and flows out from the outlet 22 below the member 16. That is, the base of the structure in which the core 3 and the cladding wall 2 in FIG. 1 are arranged is formed. On the other hand, in the clad layer, the resin B introduced from the resin inlet 33 of the side plate 12 that supplies the resin B serving as the clad layer is branched into two flow paths 34 by the side plate 13. Next, the resin flows into the liquid reservoir 35 of the resin B to be the clad layer, and is uniformly widened and merged so as to become a surface layer portion of the resin flow having a structure in which the core and the clad wall are arranged. More outflow. The timing of this merge is preferably as early as possible. That is, the distance from the tip (top) of the slit to the junction is preferably 100 mm or less. More preferably, it is 50 mm or less.

  When such a pinol-integrated feed block is used, the number of cores can be easily adjusted by the number of slits. The core diameter can be easily adjusted by the slit shape (length, gap), fluid flow rate, and degree of compression in the width direction. In particular, the reduction in the core width can be dealt with by widening the slit gap at both ends in the film width direction of the slit plate as shown in FIG. Alternatively, this can be dealt with by narrowing the gap between the slits of the core. The core thickness can be achieved by adjusting the casting speed. On the other hand, the shape of the core is basically a square shape, but by adjusting the viscosity difference between the resin A and the resin B, the square shape is deformed in the flow process, becomes an ellipse, It can be made into a circle. The preferred number of slits is 5 or more and 3000 or less per slit plate. If the number is less than 5, the number of cores is too small, and the efficiency is not good in terms of scale. On the other hand, when the number is more than 3000, it becomes difficult to control the flow rate unevenness, and the accuracy of the core diameter in the film width direction is insufficient, so that it becomes difficult to connect light. More preferably, it is 50 or more and 1000 or less. In this range, it is possible to provide a very efficient multi-channel optical waveguide while controlling the core diameter with high accuracy. In addition, when it has 200 or more cores, it is preferable to use a feed block having two or more slit plates separately. This is because if there are 400 or more (200 or more cores) slits in one slit plate, it is difficult to make the flow rate of each slit uniform.

  The fluid having the arrangement structure of the resin A and the resin B and the clad layer of the resin B thus obtained is not contracted in the width direction in the die shown in FIG. Only through this, a structure having an embodiment of the present invention is formed. FIG. 9 is a sectional view showing an example of a die used in the present invention. The die shown in FIG. 9 has a single inlet, and is constituted by a die lip 38 serving as a die discharge port after being contracted at an angle φ of the contracted portion 37 in the thickness direction. If the angle φ of the contracted portion 37 in the thickness direction is too large, it is preferable that the taper is as gentle as possible in order to induce core width and core interval unevenness. A preferable φ is 60 degrees or less. More preferably, it is 30 degrees or less. More preferably, it is 15 degrees or less. Further, the wall surface of the polymer flow path has a mirror finish with a surface roughness of 0.8 S or less, more preferably 0.2 S or less, from the viewpoint of suppressing the core width and core interval unevenness. Mirror finish can be achieved by nickel or hard chrome plating or high precision polishing.

  By using the pinol-integrated feed block and the die, the sheet discharged from the die has the structure of the optical waveguide film which is a preferred embodiment of the present application as shown in FIG. 1 and FIG.

  Then, by cooling and solidifying on a casting drum having a surface roughness of 0.2S, an optical waveguide film in which the core extends in the longitudinal direction and four or more cores are arranged in the film width direction is obtained. In addition, the cross-sectional shape of the polymer flow path in the pinol-integrated feed block is preferably a square shape from the viewpoint of uniform width direction lamination. The length is preferably 4 or more. More preferably, it is 15 or more. In addition, in order to maintain the flatness of the resulting film, when it is cooled and solidified, it is statically adhered to a cooling body such as a casting drum by electrostatic force using an electrode such as a wire, tape, needle or knife. It is preferable to use an electric application method. The electrostatic application method is a method in which a voltage of about 3 to 10 kV is applied to a wire such as tungsten to generate an electric field, and the molten sheet is electrostatically adhered to the casting drum to obtain a cooled and solidified sheet. That's it. In addition, by blowing air from a slit-like, spot-like, or planar device and bringing it into close contact with a cooling body such as a casting drum, a known surface roughness of 0.4 to 0.2 S level HCr-plated touch roll, etc. You may cast it as a calendar. The discharge sheet thus obtained is cooled and solidified by a casting drum, a calendering roll or the like. When discharging from the die, the core interval may fluctuate due to a neck-down phenomenon, so it is preferable to provide an edge guide 39 at the end of the die lip as shown in FIG. The material of the contact surface of the edge guide with the resin may be any metal such as mirror-finished SUS, copper, or brass. Moreover, it is also preferable to perform fluorine processing on the surface which becomes a wetted surface. More preferably, Teflon (registered trademark) having heat resistance, slidability and releasability is preferable. Particularly preferably, a film formed of a fluororesin film during nickel plating realizes stable casting of the film edge without generating any trouble due to self-lubricating property, improved sliding property and appropriate releasability. Therefore, high core interval accuracy can be achieved. However, this is not the case when the cladding is made of a fluororesin. Moreover, it is preferable to use what has a heater function from a viewpoint of achieving generation | occurrence | production prevention and high core space | interval precision for an edge guide. The edge guide is provided between the die lip 38 and the cooling body 41 as shown in FIG. 9 in order to constrain the end of the resin film discharged from the die, and the edge guide and the resin are in slight contact with each other. By doing so, the neck-down phenomenon is suppressed by the surface tension. By doing so, the resin film discharged from the die is thinned in the thickness direction due to the relationship between the discharge amount and the take-off speed, but the width direction dimension hardly changes. The positional accuracy of the direction is improved.

  On the other hand, when the core width is reduced outside the die, the distance between the LDs, which is the distance from the die lip of the optical waveguide film to the landing point of the cooling medium 41 as shown in FIG. 46 is set to be 3 times or more of the lip width of the die, and uniaxial extension with neck-down is performed, and cooling and solidification is performed with a cooling medium. Here, the landing point is the position in the center in the width direction of the landing line where the optical waveguide film is grounded on the cast drum. From the viewpoint of miniaturizing the core width to less than 50 μm, the distance between the LDs should be at least 3 times, more preferably at least 5 times the lip width of the die. Next, the cooling roll 43 is obtained and guided to the stretching roll 44.

  The obtained optical waveguide film 40 of the present invention is subjected to stretching, heat treatment, and the like as necessary, and is wound by a winder. Stretching and heat treatment are preferable from the viewpoint of reducing the roughness of the core surface at the interface between the core and the clad. The stretching temperature is preferably not less than the glass transition point (Tg) of the core and clad thermoplastic resin and not more than the melting point. The draw ratio is preferably 1.05 times or more and 3 times or less from the viewpoint of imparting bending resistance without causing birefringence of the core in the film width direction. More preferably, it is 1.1 times or more and 2 times or less. The stretching method is preferably a known roll-to-roll stretching method, but it is preferable to employ zone stretching from the viewpoint of suppressing neck down. Zone stretching is a stretching method in which local heating is uniformly performed in the film width direction using a near-infrared heater 45 disposed between rolls at an appropriate distance so that neck-down hardly occurs. On the other hand, when the core width and the core interval are refined by stretching, the stretching section is taken at 3 times or more of the film width, and the stretching ratio is made 2 or more, so that it is miniaturized in the thickness and width directions at the same scale. . In order to make it finer at an equal scale, it is preferable that the stretching temperature is equal to or higher than the glass transition point of the core and satisfies the relationship of the glass transition point of the core> the glass transition point of the cladding. More preferably, the relationship of drawing temperature> core glass transition point> cladding melting point is satisfied. This is because both the core and the clad are stretched uniaxially.

  On the other hand, heat processing can be achieved by passing through the spray oven with a normal nozzle. The heat treatment temperature is preferably carried out at or above the softening point of the core from the viewpoint of reducing the roughness of the core surface. Further, from the viewpoint of imparting thermal dimensional stability, it is also preferable to perform a relaxation treatment of 5% or less in the longitudinal direction of the film. More preferably, it is 2% or less.

  It is also preferable to cover a jacket for protecting the optical waveguide film of the present invention. Nylon, polyethylene, and vinyl chloride are preferable because the jacket characteristics require flame retardancy and flexibility. The jacket preferably contains a pigment such as carbon black from the viewpoint of blocking external light from entering the core.

An evaluation method of physical property values used in the present invention will be described.
(Method for evaluating physical properties)
(1) Observation of the cross-sectional structure of the optical waveguide film The cross-sectional structure of the optical waveguide film is a cross-sectional observation using an optical microscope after pre-processing by polishing the cross-section (width-direction-thickness-direction cross-section) cut out with a cutter. went. In the polishing method, the cut sample was fixed using a special jig for sheeting, and polishing was performed using a polishing apparatus NAP-240VR manufactured by Nisshin Kasei Co., Ltd. The polishing conditions are abrasive paper # 800 to # 10000, polishing liquid: water.

  Subsequently, all the cross sections in the thickness direction-width direction of the film were photographed using a Leica optical microscope DMLM. The photographing conditions were adjusted as appropriate so that the transmission / reflection mode, objective lens: x10 to x100, and focal length were appropriately adjusted so that a clear image was obtained, and the observation magnification was adjusted so that the entire thickness direction was in the field of view. By this photographing, the number of cores and the number of cladding walls were measured. The captured images were saved to a computer as image data using the included software AxioVision3.0.

  For measurement of various distances such as core diameter, unevenness difference, core width, core thickness, etc., the measured image data was used and measured by image processing software Image-Pro Plus ver.4 (distributor Planetron Co., Ltd.). Went long. Length measurement was performed in manual measurement mode according to the definition of various distances after scaling. The length measurement location was the core at the center in the film width direction.

(2) Core width unevenness, core interval unevenness, core eccentricity The core width was measured for all the cores in the film width direction of the obtained samples according to the procedure of the evaluation method (1). The core width here indicates an interval at which the core contacts two parallel lines arranged in the film width direction as shown in FIG. The unevenness of the core width was obtained as a value obtained by dividing the difference between the maximum and minimum core widths in all the film width directions by the core width in the central portion in the film width direction and multiplying by 100.

  On the other hand, about the core space | interval, it evaluated in the following procedures from the core image of all the film width directions obtained by the evaluation method (1) term. First, if necessary, image processing was performed. The image processing is performed to make the core shape clear, and includes binarization and low-pass filter processing attached to the software.

Subsequently, in the image analysis, in the parallel chic profile mode, all the cores are sandwiched between two parallel lines in the film thickness direction, and the relationship between the position and the average brightness between the lines is expressed as numerical data. I read it. Using the spreadsheet software (Excel2000), the data of the position (μm) and the brightness was adopted in the sampling step 6 (thinning 6) and then subjected to numerical processing of a three-point moving average. Further, the data obtained by changing the brightness with respect to the length in the film width direction is differentiated, and the maximum value and the minimum value of the differential curve are read by the VBA program, and the extreme value 2 located at both ends of the core is read. All the midpoints were calculated as core center positions. Next, these adjacent intervals were calculated as the core interval 7 shown in FIG. This operation was performed for all photographs of the cross section in the film thickness direction-width direction of the optical waveguide film, and the unevenness of the core interval was obtained.
The unevenness (Vl) in the core interval is defined as in the following formula (2).
Vl = (Lmax−Lmin) / Lave × 100 (%) Formula (2)
Vl: Unevenness of core interval Lmax: Maximum core interval Lmin: Minimum core interval Lave: Average value of core interval In addition, the unevenness of the core interval is excluded from the core interval adjusting portions at both ends in the film width direction of the optical waveguide film. did.

  Furthermore, the core eccentricity was calculated from the core images in the film width direction using the attached image processing software Image-Pro Plus ver.4 (distributor Planetron Co., Ltd.). The average value of the eccentricity for all cores was obtained.

(3) Average roughness Ra and maximum height Rmax of the core surface
A sample was cut out from the central part in the width direction of the film with a size of 2 cm in the width direction and 6 cm in the longitudinal direction, and further, only the core part was taken out from the optical waveguide film by cutting into the cladding layer. Sample length 4cm. This sample was fixed on a Si wafer with a tape. Next, using a scanning confocal laser microscope (ols3000 manufactured by Olympus Corporation), the sample surface adjacent to the cladding layer was observed with an objective lens of 5 to 100 ×, and the scanning range in the longitudinal direction was 100 μm. The surface roughness Ra and Rmax were analyzed with the software (ver. 5) attached to the apparatus. The average of the number of measurements was 3 times. However, the observation surface of the core surface was the opposite side of the cut.

(4) Crystal grain size The crystal grain size was measured using a thin film X-ray diffractometer RAD-C manufactured by Rigaku Corporation. The measurement conditions of the X-ray source were a radiation source CuKα, a voltage of 40 kV, a current of 30 mA, a scanning range (2θ) of 5 to 55 °, a scanning speed of 2 ° / min, and the X-ray incidence was a through view.
The spectrum analysis used the main peak observed by 2 (theta) = 10-30 degrees confirmed by this measurement. The crystal grain size was determined from the (110) plane appearing around 20 ° which is the main peak, using the Scherrer formula of Formula (3). In addition, description of "-" in Table 1 means that the diffraction peak did not exist. For Examples 19, 20, and 21, the crystal grain size was determined for ethylene-propylene copolymer, not nylon 6.

Grain size = 0.9 * λ / (B * cosθ) Equation (3)
(B: Half width, λ: 1.5406 angstrom)
(5) Refractive index The refractive index of the resin was measured according to JIS K7142 (1996) A method. In addition, the refractive index of resin in this invention was measured about each resin simple substance which comprises an optical waveguide film. Using this value, the NA value was calculated. A sample for measurement was obtained by drying each resin and then melt-pressing it.

(6) Melting enthalpy ΔH, crystal melting temperature Tm
The clad part was cut out from the optical waveguide film, the sample was weighed by 5 mg with an electronic balance, sandwiched between aluminum packings, JIS-K-7121 and 7122 ( 1987), measurement and calculation were performed. First, at 1st Run, 20 ° C / min. From 25 ° C to 300 ° C. And then cooled rapidly to 25 ° C. Subsequently, at 2nd Run, 20 ° C./min. The temperature was raised. The melting enthalpy ΔH and the crystal melting temperature Tm of the resin were obtained by analyzing the melting peak at 2nd Run. In addition, description of "-" in Table 1 means that the melting peak did not exist.
Equipment: “Robot DSC-RDC220” manufactured by Seiko Electronics Industry Co., Ltd.
Data analysis "Disc Session SSC / 5200"
(7) It was performed in accordance with JIS C6823 (1999) cutback method (IEC 60793-C1A) in an environment of propagation loss of 25 ° C. and 65% RH. Samples were prepared with test lengths of 10 cm, 9 cm, 8 cm, and 7 cm, and the insertion loss of each sample was measured. As a light source, an LED having a wavelength of 850 nm (Anritsu 0901A) was used, and light was input to the sample via a mode scrambler. As the optical fiber, a multi-mode fiber type GI (NA 0.21) having an input side diameter of 50 μm and an SI type (NA 0.22) having a detection-side core diameter of 0.2 mm were used. For samples with a core diameter of less than 40 μm, a single mode fiber with a diameter of 10 μm was used on the input side. In addition, the optical axis alignment was performed for the input-output of light using the aligner. In addition, an optical power sensor (MA9421A manufactured by Anritsu Corporation) was used as a detector. Propagation loss was determined by the least square method by plotting insertion loss against length. That is, the linear slope obtained was defined as propagation loss. Also, when the least square, the contribution rate R ² is adopted as the propagation loss only when the 0.99 or more. In the case of 0.99 or less, a value of 0.99 or more was obtained by repeating remeasurement such as realignment and resample adjustment. The core used for the measurement was the core at the center in the film width direction. In addition, the optical input / output part end surface of the sample was subjected to pre-processing of mirror polishing and ultrasonic water washing before loss measurement. The pretreatment method conforms to item (1) of the evaluation method. In the following evaluation, the same pretreatment was performed on the sample for measuring the optical loss.

(8) Peel test A test was conducted according to JIS K5600 (2002). The film was regarded as a hard substrate, and 25 lattice patterns were cut at intervals of 2 mm. Further, a tape cut to a length of about 75 mm was adhered to the lattice portion, and the tape was peeled off at an angle close to 60 ° in a time of 0.5 to 1.0 seconds. Here, Sekisui's cello tape (registered trademark) no. 252 (width 18 mm) was used. The criteria for evaluation are as follows.
(Double-circle): When neither a lattice part peels off.
◯: When some of the lattice parts were peeled off, but no part other than the lattices was peeled off.
X: When other than the lattice part is peeled off.

(9) Evaluation of code error rate Measurement was performed in an environment of 25 ° C. and 65% RH. The pulse pattern generated by the pulse pattern generator (MP1800A manufactured by Anritsu) was converted into an optical signal using an electro-optical converter (1780 E / O 850 nm VICSEL Type manufactured by New Focus), and then cut 20 cm in the longitudinal direction of the film. Light was input to the optical waveguide film. As the optical fiber, a GI type φ50 μm multimode type (NA 0.21) was used for both the input side and the output side. In addition, the optical axis alignment was performed for the input-output of light using the aligner. The detected light was converted into an electrical signal using a photoelectric converter (New Focus, 1580-BO / E 850 nm), and then detected with an error detector (MP1800A, Anritsu).
The code error rate was evaluated based on the following criteria by detecting the error rate when a 10 GHz signal was input. Moreover, the core used for the measurement was the core at the center in the film width direction.
A: Less than 1 × 10 ⁻¹⁵ ○: 1 × 10 ⁻¹⁵ or more 1 × 10 ^−less than ¹² Δ: 1 × 10 ⁻¹² or more 1 × 10 ^−less than ⁹ ×: 1 × 10 ⁻⁹ or more

(10) The thermoplastic resin A serving as the melt viscosity difference core and the thermoplastic resin B serving as the cladding were both pre-treated by drying in an oven at 90 ° C. for 4 hours or more. The measurement conditions are as follows.
Equipment: Shimadzu Corporation Shimadzu Flow Tester CFT-500 Type A
Sample: about several grams
Melting temperature: Extrusion temperature load shown in Table 1: 100,150,200kgf (Loading started 5 minutes after starting the sample set)
Number of tests: 3
Dice: φ1mm, L = 10mm
For the data, an average of 3 test times was adopted. In addition, for the thermoplastic resins A and B, a value of a shear rate of 100 S ^ (-1) was taken, and the absolute value of the difference was defined as a difference in melt viscosity (poise). When the value at 100 could not be read, linear approximation was performed and the value was read from a linear mathematical expression.

(11) The test length of the high-temperature and high-humidity test sample was 10 cm in the length direction. The sample end face was pretreated, and the optical loss was measured on the core in the center in the width direction before the high temperature and high humidity test. The measurement method is based on the evaluation item (7). Next, the optical loss measurement was performed on the same core after leaving it to stand for 1000 hours in an environment of a constant temperature and humidity chamber (Labostar humidity cabinet LHU-112 manufactured by Tabai Co., Ltd.) having a temperature of 70 ° C. and a humidity of 90%. The loss difference before and after the test was evaluated as the loss change amount according to the following criteria. The details of the test method were as described in JPCA-PE02-05-01S (2008) 6.1.
○: Loss change amount is less than 0.5 dB. Δ: Loss change amount is 0.5 dB or more and less than 2 dB. X: Loss change amount is 2 dB or more.

(12) The test length of the long-term heat resistance test sample was 10 cm in the length direction. The sample end face was pretreated, and the optical loss was measured for the core in the center in the width direction before the heat resistance test. The measurement method is based on the evaluation item (7). Next, after leaving for 1000 hours in an environment of a gear oven (GHPS-222 manufactured by TABAI) at a temperature of 85 ° C., optical loss measurement was performed on the same core. The loss difference before and after the test was evaluated as the loss change amount according to the following criteria.
○: Loss change amount is less than 0.5 dB. Δ: Loss change amount is 0.5 dB or more and less than 2 dB. X: Loss change amount is 2 dB or more.

(13) The test length of the repeated bending test sample was 10 cm in the length direction, and the sample width was 10 mm. The sample end face was pretreated, and the optical loss was measured for the core in the center in the width direction before the heat resistance test. The measurement method is based on the evaluation item (7). Next, after the bending radius R = 5 mm, the bending angle of 135 degrees, and 1000 times of repeated bending tests, the optical loss was measured for the same core. The loss difference before and after the test was evaluated as the loss change amount according to the following criteria. The details of the test method were as described in JPCA-PE02-05-01S (2008) 6.1.
○: Loss change amount is less than 0.5 dB. Δ: Loss change amount is 0.5 dB or more and less than 2 dB. X: Loss change amount is 2 dB or more.

The following were prepared as compatibilizers.
Compatibilizer: Sanyo Kasei Kogyo Co., Ltd. Carboxylic anhydride modified polyolefin Umex 1010
Yumex 2000
The description of “-” in the compatibilizing agent in Table 1 means no addition.

Example 1
Polymethylmethacrylate (PMMA) having a glass transition point of 100 ° C. is applied to the thermoplastic resin A as a core, and 80 mol% of vinylidene fluoride (VDF) component having a glass transition point of −35 ° C. is applied to the thermoplastic resin B as a cladding, and tetrafluoroethylene ( TFE) A copolymerized fluoropolymer having 20 mol% of a component was prepared and dried at a temperature of 90 ° C. for 8 hours or more.

Next, the resin A is supplied to the vent type extruder 1 having 3 vents, the resin B is supplied to the vent type extruder 2, and the resin B is supplied to the vent type extruder 3. After being in a molten state and passing through a gear pump and a 2 μ cut high-precision filter, Resin A and Resin B were allowed to flow into a pinol integrated feed block as shown in FIGS. The vent sucks foreign matter at 200 mmHg with a differential pressure. At this time, in the pinol-integrated feed block, the thermoplastic resin A and the thermoplastic resin B are alternately laminated in the width direction so that the resin A is at both ends of the slit plate, and a laminate of 301 layers, and an extruder The clad layer 1 made of the resin B supplied from 3 was joined to the laminated flow so as to become a surface layer, and led to a die as shown in FIG. At this time, there was no dimensional change in the film width direction of the polymer flow path shape from the pinole-integrated feed block to the die, and only the contraction in the thickness direction was performed inside the die, and the sheet was discharged from the die lip into a sheet shape. The taper angle φ of the contracted portion 37 in the thickness direction was 15 degrees. Further, the surface roughness of the polymer channel wall surface from the pinole-integrated feed block to the die lip was set to 0.5S. The distance from the slit tip to the cladding layer 1 joining was 50 mm.
The thermoplastic resin A at both ends is used as a core interval adjusting portion, and the core width is gradually reduced from the end as in the case of (a) (β) slit plate in FIG. 11 so that the target core width is obtained. Designed. The flow rate of the core interval adjustment unit was designed to be 20 times, 15 times, 10 times, 5 times, and 2 times from the end with respect to the flow rate of one core. The sheet discharged from the die is subjected to SI (electrostatic application) method with a voltage of 7 KV while the edge of the sheet is restrained by a 0.8 S copper edge guide whose surface is wetted with Teflon (registered trademark). Was brought into close contact with the cast drum and rapidly cooled and solidified at 25 ° C. Then, after trimming the core interval adjustment unit, guided to the longitudinal stretching machine, subjected to zone stretching to a stretching ratio of 1.3 at a stretching temperature of 150 ° C. by local heating of a near infrared heater disposed between the rolls, It was subjected to relaxation treatment at a heat treatment temperature of 170 ° C. in an oven and wound up by a winder. The obtained optical waveguide film was adjusted by changing the rotational speed of the cooling medium to obtain a thickness of 100 μm. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 5 μm.

( Comparative Example 3 )
Polymethylmethacrylate (PMMA) with a glass transition point of 100 ° C. is prepared for the thermoplastic resin A as the core, and polyvinylidene fluoride (PVDF) with a glass transition point of −35 ° C. is prepared for the thermoplastic resin B as the cladding at a temperature of 90 ° C. Drying for 8 hours or more was performed. The thermoplastic resin A at both ends serves as a core interval adjusting unit, and the flow rate of the core interval adjusting unit at both ends, such as (a) (α) slit plate in FIG. 11, is 50 times the flow rate of one core. Designed with

  An optical waveguide film cooled and solidified on a 25 ° C. casting drum was obtained in the same manner as in Example 1 except for the changes shown in Table 1. Note that stretching and heat treatment were not performed. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 10 μm.

Example 3
An amorphous fluoroalkyl methacrylate polymer having a glass transition point of 89 ° C. is prepared for the thermoplastic resin A serving as the core, and an amorphous fluoroalkyl methacrylate polymer having a glass transition point of 89 ° C. for the thermoplastic resin B serving as the cladding. Drying was performed.

  Hereinafter, except for the changes shown in Table 1, after cooling and solidifying on a casting drum at 25 ° C. in the same manner as in Example 1, an optical waveguide film subjected to stretching and heat treatment was obtained. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 10 μm.

( Comparative Example 4)
Polyvinylmethacrylate (PMMA) having a glass transition point of 100 ° C. for the thermoplastic resin A serving as the core, 80 mol% of vinylidene fluoride (VDF) component having a glass transition point of 25 ° C. or less for the thermoplastic resin B serving as the cladding, tetrafluoro A copolymer fluorine polymer having an ethylene (TFE) component of 15 mol% and a hexafluoropropylene (HFP) component of 5 mol% was prepared and dried at a temperature of 90 ° C. for 8 hours or more.

Hereinafter, except for the changes shown in Table 1, an optical waveguide film was obtained in the same manner as in Comparative Example 3 . Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 9 μm .
( Comparative Example 5)
Polyethylene terephthalate copolymer (PET / G) with a hexamethylene dimethanol component having a glass transition point of 79 ° C. having a glass transition point of 79 ° C. was added to the thermoplastic resin A as a core, and 1% by weight of Umex 1010 was added to the thermoplastic resin B as a cladding. An ethylene propylene copolymer (EPC) having a glass transition point of −20 ° C. and an ethylene component of 4 mol% was prepared and dried at a temperature of 90 ° C. for 8 hours or more.

Thereafter, an optical waveguide film was obtained in the same manner as in Comparative Example 3 except that the extrusion temperature was changed to 280 ° C. shown in Table 1 and the number of core interval adjusting portions was changed. The thermoplastic resin A from both ends to the fourth core acts as a core interval adjustment unit, and is discharged from the end at a flow rate ratio of 4: 3: 2: 1, thereby suppressing the change in the core shape and the core width. Adjusted. Specifically, using a slit plate as shown in FIGS. 11 (a) and (β), the flow rate of the core interval adjustment unit is 20 times, 15 times, 10 times, 5 times from the end with respect to the flow rate of one core. Designed with However, electrostatic application was not performed during casting. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 6 μm.

  The core was irradiated with a YAG laser to produce a 45 degree mirror. As the YAG laser, a Spectra Physics oscillator HIPPO was used. The conditions are as follows. In addition, in order to suppress generation | occurrence | production of the foreign material by a heat | fever, the 45-degree inclined surface was produced in the core by irradiating a pulse wave to a slice. There is no foreign substance on the obtained inclined surface, and when red LED light having a wavelength of 650 nm is incident from the end surface from the opposite side of the inclined surface, the light propagates in the waveguide and is emitted from the inclined surface in the direction perpendicular to the surface. It was confirmed.

Output: 0.36W MASK: □ 1mm
Wavelength: 266 nm Reduction ratio: 1 / 14.7
Frequency: 50 kHz Assist gas: He 20 l / min
( Comparative Example 6)
An optical waveguide film was obtained in the same manner as in Comparative Example 5 except that the compatibilizer was not added, except for the changes shown in Table 1. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 3 μm.

(Example 7)
Polyethylene terephthalate copolymer (PET / G) containing 30 mol% of hexamethylene dimethanol component having a glass transition point of 79 ° C. on the thermoplastic resin A serving as the core, and spiroglycol having a glass transition point of 80 ° C. on the thermoplastic resin B serving as the cladding A polyethylene terephthalate copolymer (SPG copolymer PET) having a component of 21 mol% and a hexamethylene dicarboxylic acid component of 29 mol% was prepared and dried at a temperature of 90 ° C. for 8 hours or more.

Hereinafter, except for the changes shown in Table 1, an optical waveguide film was obtained in the same manner as in Comparative Example 6. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 2 μm.

(Example 8)
Except for preparing a cycloolefin copolymer (COC: made of TOPAS 5013 polyplastic) having a glass transition point of 135 ° C. in which 1% by weight of Umex 2000 is added to the thermoplastic resin B to be the cladding, except for the changes shown in Table 1, In the same manner as in Example 5, it was rapidly solidified on a casting drum at 25 ° C. Next, the film was guided to a longitudinal stretching machine and subjected to zone stretching at a stretching temperature of 170 ° C. at a stretching temperature of 170 ° C. by local heating of a near infrared heater disposed between rolls, and a heat treatment temperature of 170 ° C. in an oven. After being relaxed, it was wound up by a winder. An optical waveguide film was obtained. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 4 μm.

( Comparative Example 7 )
Using the ethylene propylene copolymer (EPC) having a glass transition point of −20 ° C. and an ethylene component of 4 mol% for the thermoplastic resin B to be the cladding, except for the changes shown in Table 1, the same as in Example 8, An optical waveguide film was obtained. However, electrostatic application was not performed during casting. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 7 μm.

( Comparative Example 8 )
An optical waveguide film was obtained in the same manner as in Example 8 except that low-density polyethylene (LDPE) having a glass transition point of 25 ° C. or lower was used for the thermoplastic resin B serving as a clad and no stretching or heat treatment was performed. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 7 μm.

( Comparative Example 9 )
Polycarbonate (PC) having a glass transition point of 150 ° C. was prepared for the thermoplastic resin A serving as the core, and polypropylene (PP) was prepared for the thermoplastic resin B serving as the cladding, followed by drying at 90 ° C. for 8 hours or more.
An optical waveguide film was obtained in the same manner as in Comparative Example 8 except that the conditions described in Table 1 were changed. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 8 μm.

( Comparative Example 10 )
An optical waveguide film was obtained in the same manner as in Comparative Example 9 except that polypropylene (PP) in which 1% by weight of Umex 1010 was added to the thermoplastic resin B serving as the cladding was used. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 8 μm.

(Examples 13 and 14, Comparative Example 11 )
An optical waveguide film was obtained in the same manner as in Comparative Example 7 except that the conditions described in Table 1 were changed. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film.

( Comparative Example 12 )
Polystyrene (PS) with a glass transition point of 100 ° C. for the thermoplastic resin A as the core, and a methacrylate-butadiene-styrene copolymer (MBS: TH-11 electrochemical industry with a glass transition point of 93 ° C. for the thermoplastic resin B as the cladding. And dried for 8 hours or more at a temperature of 90 ° C. An optical waveguide film was obtained in the same manner as in Comparative Example 8 except that the conditions described in Table 1 were changed. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 5 μm.

( Comparative Example 13 )
Polystyrene (PS) with a glass transition point of 100 ° C. is applied to the thermoplastic resin A as the core, and a styrene / butadiene block copolymer (SBC: 210M manufactured by Denki Kagaku Kogyo) with a glass transition point of 103 ° C. as the thermoplastic resin B as the cladding. Prepared and dried at a temperature of 90 ° C. for 8 hours or more. An optical waveguide film was obtained in the same manner as in Comparative Example 8 except that the conditions described in Table 1 were changed. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 5 μm.

( Comparative Example 14 )
Cycloolefin copolymer (COC: made of TOPAS 5013 polyplastic) having a glass transition point of 135 ° C. on the thermoplastic resin A as the core, and ethylene propylene having an ethylene component of 4 mol% at the glass transition point of −20 ° C. on the thermoplastic resin B as the cladding. A copolymer (EPC) was prepared and dried at a temperature of 90 ° C. for 8 hours or more.

Next, resin A is supplied to the vent-type extruder 1 having 3 vents, resin B is supplied to the vent-type extruder 2, and resin B is supplied to the vent-type extruder 3, and each extruder has a temperature of 280 ° C. After being in a molten state and passing through a gear pump and a 2 μ cut high-accuracy filter, Resin A and Resin B were allowed to flow into a pinol integrated feed block as shown in FIGS. The vent sucked out foreign matter at a differential pressure of 200 mmHg. At this time, in the pinol-integrated feed block, the thermoplastic resin A and the thermoplastic resin B are alternately laminated in the width direction so that the resin A is at both ends of the slit plate, and a laminate of 301 layers, and an extruder The clad layer 1 made of the resin B supplied from 3 was joined to the laminated flow so as to become a surface layer, and led to a die as shown in FIG. At this time, there was no dimensional change in the film width direction of the polymer flow path shape from the pinole-integrated feed block to the die, and only the contraction in the thickness direction was performed inside the die, and the sheet was discharged from the die lip into a sheet. The taper angle φ of the contracted portion 37 in the thickness direction was 15 degrees. Further, the surface roughness of the polymer channel wall surface from the pinole-integrated feed block to the die lip was set to 0.5S. The distance from the slit tip to the cladding layer 1 joining was 50 mm.
The thermoplastic resin A at both ends serves as a core interval adjusting portion, and the core width gradually decreases from the end as in the case of (a) (β) slit plate in FIG. The design was 20 times, 15 times, 10 times, 5 times, 2 times from the end for each flow rate. The sheet discharged from the die is closely contacted on the cast drum by an SI (electrostatic application) method with a voltage of 7 KV as shown in FIG. 12 at an LD (lip-drum) distance of 6 times the lip width of the die. It was rapidly cooled and solidified at 25 ° C. The draft ratio is 30. Next, the film was stretched to a stretching ratio of 3.3 at a stretching temperature of 150 ° C. by local heating of a near-infrared heater disposed between the rolls at a distance between the rolls of 5 times the film width. It was relaxed at the heat treatment temperature and wound up with a winder. The obtained optical waveguide film was adjusted by changing the rotational speed of the cooling medium to obtain a thickness of 60 μm. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 3 μm. An optical waveguide film having an unprecedented very narrow core interval and a uniform rectangular shape in the film width direction could be obtained.

(Example 19)
2 parts by weight of Umex 1010, 10 parts by weight of nylon 6 having a glass transition point of 35 ° C. and a melting point of 225 ° C., and 90 parts by weight of an ethylene propylene copolymer (EPC) having an ethylene component of 4 mol% at a glass transition point of −20 ° C. , Dry blended to obtain a thermoplastic resin B to be a clad. In the same manner as in Example 18, an optical waveguide film was obtained. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 8 μm.

(Example 20)
Polycarbonate (PC) having a glass transition point of 150 ° C. was used as the core thermoplastic resin A, and the mixture was cooled and solidified on a casting drum at 25 ° C. in the same manner as in Example 19 except for the contents shown in Table 1. The draft ratio is 30. Next, in the same manner as in Example 19, the film was stretched at a stretching temperature of 185 ° C., and then heat-treated at a temperature of 185 ° C., to obtain an optical waveguide film. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 10 μm.

(Example 21)
Using the same core and clad resin as in Example 19, except that the contents described in Table 1 were changed, the sheet was discharged from the die in the same manner as in Example 9, and the temperature was 25 ° C. without using an edge guide. It cooled and solidified on the casting drum. The sheet discharged from the die is in close contact with the cast drum by the SI (electrostatic application) method with a voltage of 7 KV while extending from the molten state as shown in FIG. 12 between the LDs 3 times the lip width of the die. It was rapidly cooled and solidified at 25 ° C. The draft ratio is 20. Next, the film is stretched to a stretching ratio of 2.2 at a stretching temperature of 150 ° C. by local heating of a near infrared heater disposed between rolls, and subjected to a relaxation treatment at a heat treatment temperature of 170 ° C. in an oven. It was wound up by a winder. The obtained optical waveguide film was adjusted by changing the rotational speed of the cooling medium to obtain a thickness of 100 μm. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film. The unevenness difference was 3 μm. An optical waveguide film having an unprecedented very narrow core interval and a uniform rectangular shape in the film width direction could be obtained.

(Comparative Example 1)
A lower clad layer (OP-1120LN manufactured by Denki Kagaku Kogyo) was formed on a PET film having a thickness of 16 μm (manufactured by Toray: type FB50) using a metabar so as to have a thickness of 20 μm, and photocured by ultraviolet exposure. Next, 50 μm of the core layer was laminated, and ultraviolet exposure was performed from above through a photomask with a pattern length of 10 cm of Line / Space = 50 μm / 100 μm. Next, development was performed. The roughness of the core surface was measured according to the evaluation method (3). The core layer is composed of a bifunctional acrylate bisphenoxyethanol fluorene acrylate (BPFE-A) and bisphenol acrylate as a photopolymerization compound, a bisphenol A copolymer as a monomer component, and a 4,4′-bis as a polymerization initiator. Diethylaminobenzophenone and 52,2-bis (2-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,2′-biimidazole were used. Next, after washing, an upper clad layer adjusted to a thickness of 20 μm similar to the lower clad layer was laminated and subjected to ultraviolet exposure and heat treatment at 90 ° C. to obtain an optical waveguide film. Table 1 shows the production conditions / structure and evaluation results of the obtained optical waveguide film.

(Comparative Example 2)
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 each twin-screw vent type extruder, passed through 5 sheets of FSS type leaf disk filters (filtration accuracy 5 μm), and then used as a gear pump. While measuring so that the discharge ratio is thermoplastic resin A composition / thermoplastic resin B composition = 5/1, they are merged by a known three-layer pinol (merger), and alternately B in the thickness direction. It was set as the three-layer laminated body laminated | stacked in order of / A / B. 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 75 micrometers. Table 1 shows the layer structure.

Next, ^two grooves each having a depth of 63 μm, a width of 50 μm, and a length of 10 cm were formed at intervals of 50 μm using an excimer laser with 200 Hz and a processing energy of 1 J / cm ² to form a concave and convex shape. At this time, the surface roughness of the wall surface of the convex portion serving as the core was measured. Next, a polyester-based low molecular weight compound was dissolved in ethyl acetate, poured into the groove, and dried at a temperature of less than 100 ° C. to obtain a cladding wall. Therefore, a buried optical waveguide having a length of 10 cm was obtained. Table 1 shows the structure of the layers and the results of the obtained optical waveguide film.

  The present invention can be applied to communication, illumination, design, and light guide applications. In communication applications, it can be suitably used for optical waveguides for short to medium / long distances such as inter-device optical communication and inter-device / board optical communication. Specifically, it can be used for flat panel displays, supercomputers, routers / servers, mobile phones, game machines, copying machines, in-vehicle, home optical communication applications, and the like. In lighting applications, it can be used as in-vehicle lighting such as light guide plates and anisotropic diffusion plates for LCD backlights, indirect lighting on exhibits such as museums, and room lamps. In design applications, it can be used as a signboard or illumination. The light guide can be used as an image guide such as an endoscope and a sensor such as an inspection machine.

1: Cladding layer 2: Cladding wall 3: Core 4: Core spacing adjustment section 5: Core width 6: Core thickness 7: Core spacing 8: Ridge 9: Valley 10: Concavity and convexity difference 11: Pinole integrated feed block 12: Cladding layer Side plate 13 for supplying resin B serving as: Side plate 14 for supplying resin B serving as a cladding layer 15 Liquid reservoir portion 15 for resin B serving as cladding layer 1 Resin A also having a fluid reservoir portion for resin B serving as cladding layer 1 Supply unit 16: Slit plate 17: Resin B supply unit 18 having a resin B liquid reservoir serving as the clad layer 1 19: Resin B liquid reservoir 19 serving as the clad layer 1 Side plate 20: Resin inlet 21: Liquid reservoir Portion 22: Outlet 23a, 23b: Slit 24: Lower edge 25 of the ridgeline at the top of each slit 26: Upper edge 26 of the ridgeline at the top of each slit 27: Lower edge 28: Upper edge 29: Slip Ridge line 30: Liquid reservoir 31: Fluid flow direction 32: Liquid reservoir 33: Resin inlet 34: Channel 35: Liquid reservoir 36: Example of die 37: Constriction portion 38 in the thickness direction: Die lip 39: Edge guide 40: Optical waveguide film 41: Cooling medium 42: Boundary line 43 in the flow direction of resin A and resin B: Cooling roll 44: Stretching roll 45: Near infrared heater 46: Distance between LDs

Claims (14)

Stretching method in which the lip-cast drum distance (LD) is three times or more of the lip width, which is carried out until it is discharged from the base lip in a molten state into a sheet and reaches the cast drum, and / or Alternatively, after being cooled and solidified by a cast drum, it is an optical waveguide film obtained by a method of stretching between rolls by 1.05 times or more at a melting point or more and a melting point or less of a resin as a core, and a clad as a cross-sectional shape An optical waveguide film having a structure in which four or more cores made of the thermoplastic resin A surrounded by the thermoplastic resin B are arranged in the film width direction while extending in the film longitudinal direction. Is not less than 10 μm and not more than 200 μm, and the crystal melting enthalpy ΔHm of the thermoplastic resin B to be the cladding is 35 J / g or less, and between the core and the cladding Optical waveguide film average roughness Ra of the interface between the core surface is 10nm or less. The optical waveguide film according to claim 1, wherein the thermoplastic resin A serving as a core is a cycloolefin copolymer or polycarbonate. The optical waveguide film according to claim 1 or 2, wherein the thermoplastic resin B serving as a cladding has a crystal grain size of 20 nm or less. The optical waveguide film according to any one of claims 1 to 3 , wherein the eccentricity of the core is 0.6 or more. The optical waveguide film according to claim 1, wherein the core and / or the clad contains a carboxylic anhydride-modified polyolefin. The optical waveguide film according to claim 1, comprising a 45 ° mirror in the light guide path. The optical waveguide film according to any one of claims 1 to 6, wherein a connection connector is attached. The optical waveguide film according to any one of claims 1 to 7, wherein a change amount of light loss after a heat resistance test at 85 ° C for 1000 hours is 0.5 dB or less. The optical waveguide film according to any one of claims 1 to 8, wherein an optical loss change amount after a high temperature and high humidity test at 70 ° C / 90% RH for 1000 hours is 0.5 dB or less. The illuminating device using the optical waveguide film in any one of Claims 1-9. The communication apparatus using the optical waveguide film in any one of Claims 1-9. The display apparatus using the optical waveguide film in any one of Claims 1-9. The light guide using the optical waveguide film in any one of Claims 1-9. A sheet-like fluid having a clad layer made of thermoplastic resin B is discharged from the die onto a surface layer portion having a structure in which a core made of thermoplastic resin A and a clad wall made of thermoplastic resin B are arranged in the width direction, In a setting where the distance between the LDs, which is the distance from the die lip to the landing point of the cooling medium (the distance between the lip and cast drum) is at least three times the lip width of the die, the sheet-like fluid discharged from the die is stretched. As a cross-sectional shape, four or more cores made of the thermoplastic resin A surrounded by the thermoplastic resin B serving as a clad are arranged in the film width direction while extending in the film longitudinal direction. An optical waveguide film having a structure having a core diameter of 10 μm or more and 200 μm or less, and a crystal melting enthalpy ΔHm of the thermoplastic resin B serving as a cladding is 35 / G or less, the manufacturing method of the optical waveguide film average roughness Ra of the core surface of the boundary surface between the core and the cladding is 10nm or less.

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