JP2016177142A - Method of manufacturing optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing an optical element with high productivity.SOLUTION: A method of manufacturing an optical element comprises the steps of; preparing a wire rod(s) 1A comprising a core 2 and a cover 3 and having a flattened cross-sectional shape with a long axis and short axis; laminating portions of a single wire rod 1A by folding the wire rod 1A such that surfaces 3A, 3B of the wire rod 1A crossing the short axis direction sit next to each other, or laminating a plurality of wire rods 1A such that the surfaces 3A, 3B of the plurality of wire rods 1A sit next to each other; and, while the surfaces are joined with each other, removing portions of the cover(s) 3 positioned on one side and on the other side in the long axis direction to expose the core(s) 2 on the one side and on the other side.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a method for manufacturing an optical element in which a number of band-like surfaces having a reflecting function are arranged inside.

  There is known an optical element in which a number of band-like surfaces having a reflecting function are arranged inside. As disclosed in International Publication No. 2009/131128 (Patent Document 1), by using two such optical elements, for example, a three-dimensional image is formed in the air on the side of an observer viewing an object. Is possible.

International Publication No. 2009/131128

  In the method of manufacturing an optical element disclosed in International Publication No. 2009/131128 (Patent Document 1), first, a plurality of transparent plates (acrylic resin plates or glass plates) having a metal reflecting surface formed on one side are prepared. To do. A laminated body is formed by laminating a plurality of transparent plates so that the metal reflecting surface is arranged on one side. An optical element (light control panel) is produced by cutting out the laminate so that a cut surface perpendicular to each metal reflecting surface is formed. This manufacturing method includes a process of laminating a transparent plate and a somewhat complicated process of cutting the laminate in a direction perpendicular to each metal reflecting surface, leaving room for improvement in terms of productivity. Yes.

  An object of this invention is to provide the manufacturing method of the optical element which can manufacture an optical element with high productivity compared with the former.

  An optical element manufacturing method according to the present invention includes a core material having light transmittance and a covering portion provided so as to cover the periphery of the core material, so that the cross-sectional shape has a major axis direction and a minor axis direction. A step of preparing a flat wire formed on the surface, and the surface of the wire that intersects the minor axis direction is folded back so that the surfaces of the wire are adjacent to each other. In a state where one wire is partially laminated, or the plurality of wires are laminated so that the surfaces of the plurality of wires are adjacent to each other, and the surfaces are bonded to each other. A step of exposing the core material on the one side and the other side by removing portions of the covering portion located on one side and the other side in the major axis direction.

Preferably, the wire is made of a plastic optical fiber.
Preferably, the surfaces are joined to each other by thermally welding the covering portions of the plastic optical fiber.

Preferably, the core material is made of a plastic fiber.
Preferably, the covering portion is a reflective film that is formed so as to cover the periphery of the plastic fiber and reflects light inside.

Preferably, the material of the reflective film includes a dielectric or a metal.
Preferably, the surfaces are joined together by an adhesive.

  Preferably, the above-mentioned wire rod formed in a flat shape is prepared by passing a material between a heated roller pair and applying pressure deformation.

  Preferably, the material is heated by a preheating device before being pressed against the roller pair.

  Preferably, a plurality of the roller pairs are arranged along the conveying direction of the material, and the flatly formed wire rod is added by passing the material between the heated plurality of roller pairs. Prepared by pressure deformation.

  Preferably, the heating temperature of the plurality of roller pairs with respect to the material is higher than the roller pair disposed on the upstream side in the material conveyance direction, and the roller pair disposed on the downstream side in the material conveyance direction. Is set to be lower.

  Preferably, the step of folding the one wire and partially laminating the one wire includes rotating the one wire and the jig relative to each other and surrounding the one wire around the jig. It is done by wrapping around.

  Preferably, the said wire is laminated | stacked so that the said surface may incline with respect to the lamination direction of the said wire.

  Since the above manufacturing method does not include a step of laminating a transparent plate or cutting out a laminated body, it is easy to improve productivity.

5 is a perspective view showing a first step of the method of manufacturing an optical element in Embodiment 1. FIG. 2 is a cross-sectional view showing a wire used in the method for manufacturing an optical element in Embodiment 1. FIG. It is arrow sectional drawing along the III-III line in FIG. It is sectional drawing (wire material before a deformation | transformation) for demonstrating the pressurization process of the wire used for the manufacturing method of the optical element in Embodiment 1. FIG. It is sectional drawing (wire material after a deformation | transformation) for demonstrating the pressurization process of the wire used for the manufacturing method of the optical element in Embodiment 1. FIG. 6 is a side view showing a second step of the method of manufacturing an optical element in Embodiment 1. FIG. It is arrow sectional drawing along the VII-VII line in FIG. 6 is a cross-sectional view showing a third step of the method of manufacturing an optical element in Embodiment 1. FIG. 10 is a cross-sectional view showing a fourth step of the method of manufacturing an optical element in Embodiment 1. FIG. 4 is a cross-sectional view showing a fiber array sheet obtained by the method for manufacturing an optical element in Embodiment 1. FIG. FIG. 3 is a perspective view showing a micromirror array obtained by the method for manufacturing an optical element in the first embodiment. FIG. 10 is a cross-sectional view showing another configuration of the fiber array sheet obtained by the method for manufacturing an optical element in the first embodiment. 10 is a cross-sectional view showing the method of manufacturing the optical element in the second modification example of Embodiment 1. FIG. 10 is a cross-sectional view showing a material used in the method for manufacturing an optical element in Embodiment 2. FIG. 6 is a cross-sectional view showing a core material used in the method for manufacturing an optical element in Embodiment 2. FIG. 10 is a cross-sectional view showing a wire used in the method for manufacturing an optical element in Embodiment 2. FIG. FIG. 10 is a cross-sectional view showing the method for manufacturing the optical element in the second embodiment. 10 is a cross-sectional view schematically showing a roller pair and the like used in the optical element manufacturing method according to Embodiment 3. FIG. It is arrow sectional drawing along the XIX-XIX line | wire in FIG. It is arrow sectional drawing along the XX-XX line in FIG. 10 is a cross-sectional view schematically showing a roller pair and the like used in the method for manufacturing an optical element in the first modification example of Embodiment 3. FIG. 10 is a cross-sectional view schematically showing a roller pair and the like used in the method for manufacturing an optical element in a second modification of Embodiment 3. FIG. FIG. 10 is a side view for explaining the method for manufacturing the optical element in the fourth embodiment. It is arrow sectional drawing along the XXIV-XXIV line | wire in FIG. FIG. 10 is a cross-sectional view for explaining the method for manufacturing the optical element in the fourth embodiment. FIG. 24 is a cross-sectional view for illustrating the method for manufacturing the optical element in the second modification example of the fourth embodiment. FIG. 25 is a side view for explaining the method for manufacturing the optical element in the third modification example of the fourth embodiment. FIG. 29 is another side view for explaining the method for manufacturing the optical element in the third modification example of the fourth embodiment.

[Embodiment]
Hereinafter, embodiments will be described with reference to the drawings. In the description of the embodiments, the same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

[Embodiment 1]
With reference to FIGS. 1-10, the manufacturing method of the optical element in Embodiment 1 is demonstrated. Although details will be described later, a fiber array sheet 10D (see FIG. 10) as an optical element is manufactured by carrying out the manufacturing method. The fiber array sheet 10D has a large number of strip-shaped surfaces having a reflecting function arranged therein, and light incident from one incident surface 2M (see FIG. 10) is transmitted from the other emission surface 2N (same diagram). Let it emit. Furthermore, the micromirror array 100 as shown in FIG. 11 can also be produced by using two fiber array sheets 10D.

  FIG. 1 is a perspective view showing a first step of the method of manufacturing an optical element in the first embodiment. First, a plurality of wires 1A are prepared. For convenience of illustration, only one wire 1A is shown in FIG. The wire 1A has a core material (2) having optical transparency and a covering portion (3) provided so as to cover the periphery of the core material, and can propagate light inside. In order to prepare the wire 1A, the following method can be used.

  With reference to FIG. 2 and FIG. 3, the wire 1 is prepared first. FIG. 2 is a cross-sectional view showing the wire 1. FIG. 3 is a cross-sectional view taken along line III-III in FIG. The wire 1 has a core material (2) having light permeability and a covering portion (3) provided so as to cover the periphery of the core material, and can propagate light inside (in FIG. 3). See the black arrow). The wire 1 is comprised from a plastic optical fiber as an example.

  As shown in FIGS. 2 and 3, a wire 1 as a plastic optical fiber includes a core layer 2 (core material) having optical transparency and a clad layer 3 (covering portion) provided so as to cover the periphery of the core layer 2. ). Both the core layer 2 and the clad layer 3 are formed from a thermoplastic resin.

  With reference to FIG. 4, the wire 1 is arrange | positioned inside 4 A of pressurization tools as shown in FIG. The pressing tool 4A has a flat pressing surface 4S and a pair of pressing surfaces 4T and 4U perpendicular to the pressing surface 4S. The pressing tool 5A also has a flat pressing surface 5S. The wire 1 is pressurized using the pressurizing tools 4A and 5A while heating the wire 1 so that the temperature of the wire 1 becomes 160 ° C., for example. The wire 1 (core layer 2 and clad layer 3) is softened and deformed by pressurization. The wire 1 is deformed so as to follow the shapes of the pressure surfaces 4S, 4T, 4U and the pressure surface 5S to form a wire 1A (see FIG. 5).

  As shown in FIG. 5, in the state where heating and pressurization are released, the wire 1A has a flat cross-sectional shape and has a major axis direction D1 and a minor axis direction D2. The term “flat” used herein refers to a shape having a major axis direction D1 and a minor axis direction D2, such as a rectangular shape, an elliptical shape, and an ellipse shape, and a dimension taken in the minor axis direction D2 is taken in the major axis direction D1. It means a shape shorter than the dimension.

  The surfaces 3C and 3D intersecting the major axis direction D1 of the wire 1A (in other words, the surfaces 3C and 3D positioned at both ends in the major axis direction D1) have a flat surface shape. The surfaces 3A and 3B intersecting the short axis direction D2 of the wire 1A (in other words, the surfaces 3A and 3B positioned at both ends of the short axis direction D2) also have a flat surface shape.

  The wire 1A obtained by deformation maintains the cross-sectional configuration of the core layer 2 and the clad layer 3 of the wire 1 before deformation (configuration in which the clad layer 3 is positioned so as to cover the periphery of the core layer 2). Yes. The wire 1A also has a function of propagating light inside, similarly to the wire 1 (FIG. 4). The wire 1 (FIG. 2 etc.) can form the wire 1A which has such a shape by deformation | transformation.

  Such a wire 1A can be produced, for example, by pressure-deforming a plastic optical fiber (wire 1) having a wire diameter of φ1 mm (FIGS. 2 to 5). The wire diameter of the wire 1 is not limited to φ1 mm, and may be optimized according to the specifications (image quality, etc.) of the optical system to which the optical element is applied.

  Referring again to FIG. 1, the wire 1 </ b> A of the present embodiment includes a core layer 2 (core material) having optical transparency and a clad layer 3 (covering portion) provided so as to cover the periphery of the core layer 2. And have. Both the core layer 2 and the clad layer 3 are formed from a thermoplastic resin. For example, the core layer 2 has a higher refractive index than the cladding layer 3, the core layer 2 is formed from a polymethyl methacrylate resin, and the cladding layer 3 is formed from a fluorine-based polymer. The thickness of the cladding layer 3 is, for example, 10 μm.

  As shown by the arrow AR in FIG. 1, the plurality of wires 1A are sequentially stacked on the pressing surface 4S of the pressing tool 4C. The plurality of wire rods 1A all extend linearly along the arrow Y direction. The plurality of wires 1A are sequentially stacked so that the surfaces 3A and 3B intersecting in the minor axis direction are adjacent to each other (in other words, the long sides of the plurality of wires 1A are in contact with each other) (see FIG. 7). ). Assuming that the pressing surface 4S has a shape extending in the XY plane direction, the plurality of wires 1A are sequentially stacked in the arrow Z direction orthogonal to the XY plane direction.

  In order to restrict the movement of the wire 1A in the direction of the arrow X and in the opposite direction, restriction tools 6C and 7C are used as necessary. The inner surfaces 6S, 7S of the restrictors 6C, 7C are orthogonal to the pressure surface 4S. FIG. 6 is a side view showing the second step of the method of manufacturing an optical element in the first embodiment. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

  Referring to FIGS. 6 and 7, after laminating a plurality of wires 1 </ b> A, pressurizing tool 5 </ b> C having pressurizing surface 5 </ b> S is arranged so as to be in contact with wire 1 </ b> A located at the uppermost portion (end in the arrow Z direction) Is done. The pressing surfaces 4S and 5S are parallel to each other (see FIG. 7). The plurality of wires 1A are pressurized in the same direction as the direction in which the plurality of wires 1A are stacked (stacking direction DR).

  The pressurizing tools 4C and 5C and the regulating tools 6C and 7C have a built-in heater and the like, and pressurize the plurality of wire rods 1A while heating them. Alternatively, the plurality of wires 1A may be pressurized after being heated. The plurality of wires 1A are heated so that the temperature becomes equal to or higher than the temperature at which the cladding layer 3 (coating layer) softens or melts. The plurality of wires 1A are pressurized and heated for about 5 minutes such that the temperature of each wire 1A is, for example, 160 ° C.

  Referring to FIG. 8, when the clad layer 3 is softened or melted by heating, the clad layers 3 (coating portions) of adjacent wire rods 1A are integrated by heat welding, and the plurality of wire rods 1A are joined to each other. Thereby, the fiber array 10C shown in FIG. 8 is obtained. The fiber array 10C has a thin plate shape (sheet shape) in a state where heating and pressurization are released. The fiber array 10C maintains a state in which the clad layers 3 are bonded to each other. After releasing the heating and pressurization, a cooling step may be performed as necessary.

  Referring to FIG. 9, the fiber array 10C formed by bonding the clad layers 3 to each other is subjected to a grinding process and / or a polishing process. Of the clad layer 3 (covering portion), portions on one side and the other side that intersect the major axis direction of the wire 1A (portions forming the surfaces 3C and 3D in the clad layer 3) are removed. Thereby, a part of core layer 2 can be exposed in one side and the other side in the major axis direction of wire 1A.

  In the present embodiment, a part of the core layer 2 (core material) is also removed. Specifically, portions 2C and 2D on one side and the other side of the core layer 2 that intersect the long axis direction of the wire 1A are removed. Thereby, a part of core layer 2 can be further exposed in one side and the other side in the major axis direction of wire 1A. The exposed surface of the core layer 2 (incident surface 2M) and the other surface (exit surface 2N) are preferably subjected to mirror treatment. These surfaces (incidence surface 2M and exit surface 2N) are preferably parallel to each other. Furthermore, the interface between the core layer 2 and the cladding layer 3 is preferably orthogonal to the incident surface 2M and the emitting surface 2N and parallel to each other.

  Referring to FIG. 10, a fiber array sheet 10D (optical element) is obtained through the above steps. The cladding layer 3 of the fiber array sheet 10D does not have a reflection function by being removed in the above-described portions (surfaces 3C and 3D (FIG. 9)) in the long axis direction (arrow X direction), but is adjacent to the fiber array sheet 10D. The strip-shaped portion remaining between the wire 1A exhibits a reflecting function.

  The fiber array sheet 10D has a configuration in which the remaining portions of the core layer 2 and the cladding layer 3 are arranged at an equal pitch, and reflects the light incident from the incident surface 2M on one side, The light can be emitted from the other emission surface 2N (see the black arrow in FIG. 10). For convenience, the width of the entrance surface 2M is defined as W2, and the distance between the entrance surface 2M and the exit surface 2N is defined as L2.

  Referring to FIG. 11, micromirror array 100 as shown in FIG. 11 can be manufactured by using two fiber array sheets 10D. In the micromirror array 100, a plurality of core layers 2 provided on each of the fiber array sheets 10D intersect with each other at an angle of 90 ° (right angle). Light incident from the incident surface 2M on one side of the fiber array sheet 10D (10D1) is guided through the core layer 2 of the fiber array sheets 10D (10D1) and 10D (10D2), and the core layer 2 and the cladding layer 3 are guided. And is emitted from the emission surface 2N on the other side of the fiber array sheet 10D (10D2).

  Such a micromirror array 100 can form a mirror image of a projection object arranged on one side of the micromirror array 100 at a spatial position on the other side that is plane-symmetric with respect to the micromirror array 100. it can. The micromirror array 100 functions as an imaging optical element for imaging a three-dimensional or two-dimensional object and image in space.

(Function and effect)
In the method of manufacturing an optical element in the first embodiment, a fiber array 10C (FIG. 8) is formed by bonding a plurality of wires 1A having a flat cross-sectional shape, and a part of the core layer 2 is exposed. Thus, the fiber array sheet 10D (FIG. 10) is produced. Unlike the case of International Publication No. 2009/131128 (Patent Document 1) described at the beginning, the manufacturing method according to the first embodiment does not include a step of laminating a transparent plate or cutting out a laminate. . Equipment for preparing the transparent plate is also unnecessary, and equipment for cutting is also unnecessary. It can be said that the manufacturing method of the reference technique not only can suppress an increase in material cost and cost for production equipment, but also can manufacture an optical element by a simple process and easily improve productivity.

  In the method of manufacturing an optical element in the first embodiment, a fiber array 10C (FIG. 8) is formed by joining a plurality of wires 1A having a flat cross-sectional shape. In the state in which the plurality of wire rods 1A are joined, the plurality of wire rods 1A form a state of being aligned along the minor axis direction D2 (corresponding to the arrow Z direction).

  Thereafter, in order to form the entrance surface 2M and the exit surface 2N, the portion of the wire 1A that intersects the major axis direction (the portion of the cladding layer 3 where the surfaces 3C and 3D are formed) is removed. Thereby, the fiber array sheet 10D (FIG. 10) can be obtained. In the fiber array sheet 10D, the core layer 2 is exposed on one side and the other side in the major axis direction of the wire 1A. That is, the exposed portion of the core layer 2 is a short side portion of the flat shape, and the cladding layer 3 remains on the long side portion of the flat shape (see FIG. 10).

  Therefore, when the fiber array sheet 10D is manufactured by performing the manufacturing method of the first embodiment, the distance L2 (height) between the incident surface 2M and the exit surface 2N is larger than the width W2 of the incident surface 2M. Can be lengthened. When the fiber array sheet 10D is applied to the imaging optical element, it is possible to capture many light rays that contribute to the aerial image (in other words, it is possible to efficiently contribute the captured light rays to the aerial image). , Can improve the brightness of the image. The ratio (W2 / L2) between the width W2 and the distance L2 is optimized according to the position of the light source and the line-of-sight angle from the observer. For example, the ratio is set to a range of 1/5 or more and 1/1 or less. It is preferable.

  Since the value of the distance L2 is larger than the width W2, the distance L2 between the incident surface 2M and the exit surface 2N can be arbitrarily set with respect to the width W2 of the incident surface 2M. That is, the value of the distance L2 with respect to the width W2 can be easily obtained by subjecting the exposed surface (incident surface 2M) and / or the other surface (exit surface 2N) to grinding or polishing. Can be adjusted. Therefore, the width W2 and the distance L2 can be set to the same value. It is also possible to configure the width W2 to be larger than the value of the distance L2, as in the fiber array 10Da shown in FIG. The ratio (W2 / L2) between the width W2 and the distance L2 may be optimized according to the position of the light source and the line-of-sight angle from the observer.

(First Modification of Embodiment 1)
In the above-described embodiment, the clad layers 3 (coating portions) of the adjacent wire rods 1A are integrated by thermal welding to join the plurality of wire rods 1A. Not limited to heat welding, adjacent wires 1A (cladding layer 3) may be joined together by an adhesive (for example, an epoxy adhesive). A combination of heat welding and an adhesive may be performed. Alternatively, the plurality of wires 1 </ b> A use the minute cracks generated in the cladding layer 3 at the time of thermal deformation to bond the cladding layers 3 of the adjacent wires 1 </ b> A with a solvent that partially dissolves the cladding layer 3. You may join.

(Second Modification of Embodiment 1)
FIG. 13 is a cross-sectional view illustrating the method of manufacturing the optical element in the second modification example of the first embodiment. FIG. 13 corresponds to FIG. 7 in the first embodiment described above. In this modification, a spacer SP is used. The spacer SP is formed in a wedge shape as a whole, and has an inclined surface S that is inclined with respect to the lamination direction DR of the wire 1A. The pressing surface 5S of the pressing tool 5C is also inclined so as to correspond to the inclined surface S. According to this configuration, the plurality of wires 1A are stacked such that the surfaces 3A and 3B are inclined with respect to the stacking direction DR.

  After lamination, the plurality of wires 1A are heated and pressurized as in the first embodiment. In a state where the plurality of wire rods 1A are bonded to each other, portions on one side and the other side of the cladding layer 3 (covering portion) intersecting with the long axis direction of the wire rod 1A are removed. The fiber array sheet obtained in this way can give light directivity when light incident from one surface is emitted from the other surface.

[Embodiment 2]
With reference to FIGS. 14-17, the manufacturing method of the optical element in Embodiment 2 is demonstrated. The second embodiment is mainly different from the first embodiment in that a plastic fiber is used instead of the plastic optical fiber, and further, an adhesive 9 is used.

  As shown in FIG. 14, in the present embodiment, first, a core material 2E having optical transparency is prepared. The core material 2E is composed of a plastic fiber. Core material 2E does not have a member corresponding to clad layer 3 (Embodiment 1), and is made of, for example, acrylic resin. As the core material 2E, polymethacrylstyrene (MS) resin, methacrylbutadiene styrene (MBS) resin, transparent acrylonitrile / butadiene / styrene copolymer (transparent ABS) resin, styrene / butadiene copolymer (SBC) resin, etc. It may be formed.

  The core material 2E is deformed by using a pressurizing tool (pressurizing tools 4A and 5A) as described with reference to FIG. That is, the core material 2E is pressurized while being heated so that the temperature of the core material 2E becomes 160 ° C., for example. The core material 2E is softened and deformed by pressurization. The core material 2E is deformed so as to follow the shape of the pressing surface of the pressurizing tool to form the core material 2F (see FIG. 15). The core material 2F has a flat cross-sectional shape and has a major axis direction D1 (see FIG. 16) and a minor axis direction D2 (see FIG. 16).

  Referring to FIG. 16, next, a reflective film 3F as a covering portion is formed so as to cover the periphery of the core material 2F. The reflective film 3F is formed on the surface of the core material 2F (plastic fiber) and can reflect light inside (contain light inside) (see the black arrow in FIG. 16). As shown in FIG. 16, a wire 1F including a core material 2F and a reflective film 3F is obtained.

  The material of the reflective film 3F preferably contains a dielectric or metal. As a specific example, an aluminum film having a film thickness of 0.5 μm is provided as a reflective film 3F on the surface of a core material 2F formed from an acrylic resin (core material 2E) having a wire diameter of φ1 mm by vacuum deposition. be able to.

  In the wire 1F obtained as described above, the surfaces 3C and 3D intersecting the long axis direction D1 of the wire 1F (in other words, the surfaces 3C and 3D positioned at both ends in the long axis direction D1) It has a flat surface shape. The surfaces 3A and 3B intersecting the short axis direction D2 of the wire 1F (in other words, the surfaces 3A and 3B positioned at both ends of the short axis direction D2) also have a flat surface shape.

  Referring to FIG. 17, as in the case of the first embodiment, the plurality of wire rods 1F are arranged on the pressing surface 4S of the pressing tool 4C and are laminated so that the surfaces 3A and 3B are adjacent to each other. (Arrow DR direction). At this time, a small amount of adhesive 9 is supplied or applied between the adjacent wires 1F (reflective film 3F) by spraying or a dispenser. For example, an epoxy adhesive is used as the adhesive 9. Thereafter, the plurality of wires 1F are pressurized in the same direction as the direction in which the plurality of wires 1F are stacked (stacking direction DR). At this time, the plurality of wires 1F may be pressurized while being heated.

  The plurality of wire rods 1F are joined together to form a thin plate (sheet shape) fiber array. The fiber array formed by bonding the reflective films 3F to each other is subjected to grinding and / or polishing in the same manner as in the first embodiment. Of the reflective film 3F (covering portion), a portion intersecting in the long axis direction (a portion forming the surfaces 3C and 3D in the reflective film 3F) is removed. Thereby, a part of core material 2F can be exposed in the one side and other side in a major axis direction.

  If necessary, a part located on one side in the major axis direction and a part located on the other side in the major axis direction are removed from the core material 2F. The exposed surface of the core material 2F is preferably subjected to mirror surface treatment on the one side surface and the other side surface. These planes are preferably parallel to each other.

(Function and effect)
In the present embodiment, the reflective films 3 </ b> F of the adjacent wire 1 </ b> F are firmly bonded by the adhesive 9. When the adhesive 9 is used, it is easy to obtain a stronger bonding strength than the heat welding in the first embodiment. When a dielectric or metal (aluminum film) is used as the material of the reflective film 3F, various adhesives can be used, and when an aluminum film is used, the choice of adhesive is wide.

  In the case of the thermal welding according to the first embodiment, it is necessary to heat the clad layer 3 so that the clad layer 3 can be welded. In the present embodiment, a plurality of wires 1F can be joined only by heating necessary for bonding (heating itself may be unnecessary), and the thermal influence on the core 2F is implemented. This can be reduced as compared with the first embodiment. Even if heating and pressurization are performed at the time of bonding, it can be said that the second embodiment can easily reduce the thermal influence on the core material 2F as compared with the case of the first embodiment.

[Embodiment 3]
With reference to FIGS. 18-20, the manufacturing method of the optical element in Embodiment 3 is demonstrated. The third embodiment is different from the first and second embodiments in the method for preparing the wire. FIG. 18 is a cross-sectional view schematically showing the roller pair 8 used in the third embodiment. 19 is a cross-sectional view taken along the line XIX-XIX in FIG. 18, and FIG. 20 is a cross-sectional view taken along the line XX-XX in FIG.

  In the present embodiment, a roller pair 8 is used. The roller pair 8 includes two rollers 8M and 8N arranged to face each other with a space therebetween. The rollers 8M and 8N are driven to rotate in the direction of the arrow AR1 at the same peripheral speed, and the wire 1 (material) such as a plastic optical fiber passes between the rollers 8M and 8N (arrow AR2).

  The rollers 8M and 8N incorporate heat sources H1 and H2, respectively. The heat sources H1 and H2 heat the wire 1 (material) so that the temperature of the wire 1 (material) passing between the rollers 8M and 8N is equal to or higher than the softening temperature thereof. The wire 1 has a circular cross-sectional shape before passing between the rollers 8M and 8N (see FIG. 19). After the wire 1 passes between the rollers 8M and 8N, a wire 1A having a flat cross-sectional shape is obtained by pressure deformation (see FIG. 20). A wire 1A shown in FIG. 20 corresponds to the wire 1A shown in FIG. That is, the wire 1A is not limited to the method described with reference to FIGS. 4 and 5 and may be prepared using a method such as the present embodiment.

  In this embodiment, the wire 1A is produced by pressurizing and deforming the wire 1 (material) such as a plastic optical fiber, but a core 2E (plastic fiber) as shown in FIG. 14 is prepared as the material. Also good. In this case, the core material 2F as shown in FIG. 15 is obtained by heating and pressurizing the rollers 8M and 8N. A reflective film 3F (FIG. 16) is formed around the core material 2F by vacuum deposition or the like. Thereby, the wire 1F which has a flat cross-sectional shape can be obtained.

(First Modification of Embodiment 3)
As shown in FIG. 21, it is preferable to arrange preheating devices H3 and H4 on the upstream side of the roller pair 8 in the conveyance direction (arrow AR2) of the wire 1 (material). The wire 1 as a raw material is heated by the preheating devices H3 and H4 before being heated and pressurized by the rollers 8M and 8N.

  According to the said structure, compared with the case where the wire 1 (material) is deformed only by the rollers 8M and 8N, it is possible to suppress the wire 1 from being deformed into an unintended shape such as swelling or twisting when cured. It becomes.

(Second Modification of Embodiment 3)
As shown in FIG. 22, it is preferable that a plurality of roller pairs 8A, 8B, and 8C are arranged along the conveyance direction (arrow AR2) of the wire 1 (material). A flat wire 1A is obtained by sequentially passing the material (wire 1) between a plurality of heated roller pairs 8A, 8B, and 8C and applying pressure deformation.

  For example, the distance between the two rollers constituting the roller pair 8A may be different from the distance between the two rollers constituting the roller pair 8B (or the roller pair 8C). For example, the interval between the two rollers may be made smaller in the order of the roller pairs 8A, 8B, 8C. You may vary the diameter of the roller which comprises roller pair 8A, 8B, 8C. For example, the diameter of the rollers may be decreased in the order of the roller pairs 8A, 8B, and 8C. By adopting after optimizing these values, it is possible to obtain a wire rod 1A having a more preferable cross-sectional shape.

  The set temperature of the heat sources H1, H2 built in the roller pair 8A is T1, the set temperature of the heat sources H5, H6 built in the roller pair 8B is T2, and the set temperature of the heat sources H7, H8 built in the roller pair 8C Is T3, it is preferable that the relationship of T1> T2> T3 is satisfied. According to the said structure, the heating temperature with respect to the raw material (wire 1) of roller pair 8A, 8B, 8C is arrange | positioned in the downstream in the conveyance direction of a raw material compared with the roller pair arrange | positioned in the upstream in the conveyance direction of a raw material. The lower roller pair is lower. The temperature of the material will gradually decrease. The material can be gradually cured (it can be more effective than air cooling), and the material can be prevented from being deformed into an unintended shape such as swelling or twisting.

[Embodiment 4]
With reference to FIGS. 23-25, the manufacturing method of the optical element in Embodiment 4 is demonstrated. FIG. 23 is a side view for explaining the method of manufacturing the optical element in the fourth embodiment. FIG. 24 is a cross-sectional view taken along the line XXIV-XXIV in FIG.

  As described above, in the first to third embodiments, a plurality of wires (wire 1A shown in FIG. 5 or wire 1F shown in FIG. 16) are prepared. The plurality of wires are laminated so that the surfaces 3A and 3B are adjacent to each other. On the other hand, in the present embodiment, one wire 1A is used. The wire 1A is partially laminated by turning back the wire 1A a plurality of times, and the surfaces 3A and 3B are adjacent to each other.

  Referring to FIGS. 23 and 24, specifically, a plate-like jig 4J and a pair of restrictors 6J and 7J are prepared. The jig 4J has a pair of parallel placement surfaces, and is supported by the rotation shaft 4G (FIG. 23) so as to be rotatable in the direction of the arrow DR1. The restricting tools 6J and 7J are arranged so as to be orthogonal to the rotation shaft 4G and face each other with a space therebetween. For the sake of convenience, in FIG. 23, the restrictors 6J and 7J are transparently illustrated using a two-dot chain line.

  The jig 4J is provided with a locking portion 4H (FIG. 23). The jig 4J and the restricting tools 6J and 7J are integrally rotated in a state where the tip end portion of the wire 1A is locked to the locking portion 4H. You may rotate the apparatus (not shown) which sends out wire 1A with respect to the jig | tool 4J and the control tools 6J and 7J which are fixedly arranged. By rotating the single wire 1A and the jig 4J relative to each other, the single wire 1A is wound around the jig 4J. As shown in FIG. 24, when the wire 1A is viewed in cross section, the wire 1A is stacked in the direction of the arrow DR2 on one side of the jig 4J, and the wire 1A is stacked in the direction of the arrow DR3 on the other side of the jig 4J. Will be.

  Referring to FIG. 25, after partially laminating wire 1A a predetermined number of times, wire 1A is cut at the root portion (along dotted line LN shown in FIG. 23). Thereafter, the surfaces 3A and 3B are joined together by heat welding or an adhesive. Thereafter, the folded portion of the wire 1A is cut off (the wire 1A is cut along the dotted lines LN1 and LN2 shown in FIG. 23). Thereby, one fiber array 10E (FIG. 25) is produced on one side of the jig 4J, and one fiber array 10F (FIG. 25) is produced also on the other side of the jig 4J.

  The fiber arrays 10E and 10F are subjected to a grinding process and / or a polishing process in the same manner as in the first embodiment. Of the cladding layer 3 (covering portion), a portion intersecting in the major axis direction (a portion forming the surfaces 3C and 3D of the cladding layer 3) is removed. Thereby, a part of core layer 2 can be exposed in the one side and other side in a major axis direction.

(First Modification of Embodiment 4)
The portion of the wire 1A that has the folded shape may not be cut off. Referring to FIG. 23, one or both of restricting tools 6J and 7J are removed from jig 4J, and the wound body made of wire 1A is removed from jig 4J. Thereafter, the wound body is subjected to grinding treatment and / or polishing treatment in the same manner as described above, and a portion of the cladding layer 3 (covering portion) that intersects the major axis direction (the surface 3C of the cladding layer 3). , 3D forming portion) is removed. Thereby, a part of core layer 2 can be exposed in the one side and other side in a major axis direction. Depending on the specifications of the optical system, it is also possible to use an optical element having such a winding shape (spiral shape). In the fourth embodiment, the wire 1A is wound around the jig 4J. However, the wire 1F (FIG. 16) may be wound around the jig 4J.

(Second Modification of Embodiment 4)
FIG. 26 is a cross-sectional view illustrating the method of manufacturing the optical element in the second modification example of the fourth embodiment. This modification corresponds to the second modification (FIG. 13) of the first embodiment described above. In this modification, spacers SP1 and SP2 are used. The spacers SP1 and SP2 are formed in a wedge shape as a whole, and have inclined surfaces S1 and S2 that are inclined with respect to the lamination direction (DR2 and DR3) of the wire 1A, respectively. According to this configuration, the wire 1A is laminated so that the surfaces 3A and 3B are inclined with respect to the lamination directions DR2 and DR3. The fiber array sheet obtained in this way can give light directivity when light incident from one surface is emitted from the other surface.

(Third Modification of Embodiment 4)
With reference to FIGS. 27 and 28, a third modification of the fourth embodiment will be described. In the above-described fourth embodiment, the wire 1A is wound around the jig 4J by folding the wire 1A in the same direction. According to this configuration, the wire 1A is partially laminated, and the surfaces 3A and 3B are adjacent to each other.

  On the other hand, as shown in FIGS. 27 and 28, the wire 1 </ b> A may be partially laminated by being folded so as to be folded. According to this configuration, the surfaces 3A and 3A are adjacent to each other, and the surfaces 3B and 3B are adjacent to each other. After the surfaces 3A and 3A are joined together by heat welding or an adhesive, and the surfaces 3B and 3B are joined together, the portion of the wire 1A that has a folded shape is cut off as necessary (the wire 1A is , And cut along the dotted lines LN1 and LN2 shown in FIG.

  Thereafter, a grinding process and / or a polishing process are performed in the same manner as described above. Of the cladding layer 3 (covering portion), a portion intersecting in the major axis direction (a portion forming the surfaces 3C and 3D of the cladding layer 3) is removed. Thereby, a part of core layer 2 can be exposed in the one side and other side in a major axis direction.

  The embodiment and the modification have been described above, but the above disclosure is illustrative in all respects and not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 wire rod (material), 1A, 1F wire rod, 2 core layer (core material), 2C, 2D part, 2E, 2F core material, 2M entrance surface, 2N exit surface, 3 clad layer (coating layer), 3A, 3B, 3C, 3D surface, 3F reflective film (coating layer), 4A, 4C, 5A, 5C pressure tool, 4G rotary shaft, 4H locking part, 4J jig, 4S, 4T, 4U, 5S pressure surface, 6C, 6J , 7C, 7J Restrictor, 6S, 7S Inner surface, 8, 8A, 8B, 8C Roller pair, 8M, 8N roller, 9 Adhesive, 10C, 10Da, 10E, 10F Fiber array, 10D Fiber array sheet, 100 Micromirror Array, AR, AR1, AR2, DR1 arrow, D1 long axis direction, D2 short axis direction, DR, DR2, DR3 stacking direction, H1, H2, H5, H6, H7, H8 heat source, H3 H4 preheater, L2 distance, LN, LN1, LN2 line, S, S1, S2 inclined surfaces, SP, SP1, SP2 spacer, W2 width.

Claims (13)

A step of preparing a wire rod that includes a light-transmitting core material and a covering portion that is provided so as to cover the periphery of the core material, and is formed flat so that a cross-sectional shape has a major axis direction and a minor axis direction When,
Regarding the surface of the wire that intersects the minor axis direction, the one wire is folded so that the surfaces of the one wire are adjacent to each other, or the one wire is partially laminated, Alternatively, a step of laminating a plurality of the wires so that the surfaces of the plurality of wires are adjacent to each other;
The core material is removed from the one side and the other side by removing portions located on one side and the other side in the major axis direction of the covering portion in a state where the surfaces are bonded to each other. Exposing in
A method for manufacturing an optical element. The wire is composed of a plastic optical fiber,
The manufacturing method of the optical element of Claim 1. The surfaces are joined together by thermally welding the covering parts of the plastic optical fiber,
The manufacturing method of the optical element of Claim 2. The core material is composed of plastic fiber,
The manufacturing method of the optical element of Claim 1. The covering portion is a reflective film that is formed so as to cover the periphery of the plastic fiber and reflects light inside.
The manufacturing method of the optical element of Claim 4. The material of the reflective film includes a dielectric or a metal,
The method for manufacturing an optical element according to claim 5. The surfaces are joined together by an adhesive,
The manufacturing method of the optical element in any one of Claim 1 to 6. The wire formed into a flat shape is prepared by causing a material to pass between a heated roller pair and causing pressure deformation.
The manufacturing method of the optical element in any one of Claim 1 to 7. The material is heated by a preheating device before being pressed against the pair of rollers.
The manufacturing method of the optical element of Claim 8. A plurality of the roller pairs are arranged along the conveying direction of the material,
The wire formed in a flat shape is prepared by causing the material to pass between a plurality of heated roller pairs and pressurizing and deforming,
The method for producing an optical element according to claim 8 or 9. The heating temperature of the plurality of roller pairs with respect to the material is higher in the roller pair disposed on the downstream side in the material conveyance direction than in the roller pair disposed on the upstream side in the material conveyance direction. Set to be lower,
The manufacturing method of the optical element of Claim 10. The step of folding the one wire rod and partially laminating the one wire rod rotates the one wire rod and the jig relative to each other and winds the one wire rod around the jig. Done
The method for manufacturing an optical element according to claim 1. The wire is laminated such that the surface is inclined with respect to the lamination direction of the wire,
The manufacturing method of the optical element in any one of Claim 1 to 12.