Light transmission direction control body, manufacturing method of louver film, and manufacturing method of light transmission direction control body

Abstract

To provide a light transmission direction control body capable of allowing light emitted from a curved surface to be in parallel (aligning direction of light), a method for manufacturing a louver film that the light transmission direction control body has, and a method for manufacturing a light transmission direction control body.SOLUTION: A light transmission direction control body 1 includes a transparent adherend 10 having a curved surface 10a, and a louver film 20 stuck to the curved surface 10a, the louver film 20 has a plurality of light transmission bands 21 and a plurality of glare protection bands 22, the light transmission bands 21 and the glare protection bands 22 are disposed in parallel alternately in a plan view of the louver film 20 from a side of the curved surface 10a, center lines extended in a thickness direction of the louver film 20 of the plurality of glare protection bands 22 are mutually and nearly in parallel on a section of the louver film 20 cut by a virtual surface orthogonal to a longitudinal direction of the light transmission bands 21 in a plan view, and the light transmission bands 21 and the glare protection bands 22 include elastomer.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a light transmission direction control body, a method for manufacturing a louver film, and a method for manufacturing a light transmission direction control body. [Background technology]

[0002] In recent years, light sources such as light-emitting diodes (LEDs) have been used to illuminate parts of the exterior (face) of buildings or facilities such as windows on exterior walls at night to promote the presence of the building. Illuminating buildings in this way creates a nighttime urban landscape, and creates a three-dimensional effect and aesthetic effect on the building that cannot be seen during the day.

[0003] For example, in order to emphasize the three-dimensional effect of a building, it is desirable to illuminate only a specific portion of the building. In order to illuminate only a specific portion, it is necessary to increase the directivity of the light emitted from the light source.

[0004] Conventionally, a viewing angle controller in which the louver angle is uniform across the entire louver layer is known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2008-102278 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, when the view angle controller of Patent Document 1 is attached to a curved surface, it is not possible to collimate the light that passes through the view angle controller.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a light transmission direction control body that can parallelize light exiting a curved surface (align the direction of light), a manufacturing method for a louver film to be provided on the light transmission direction control body, and a manufacturing method for a light transmission direction control body. [Means for solving the problem]

[0008] [1] A light transmission direction control body comprising a light-transmitting substrate having a curved surface and a louver film attached to the curved surface, wherein the louver film has a plurality of light transmission bands and a plurality of light-shielding bands, the light transmission bands and the light-shielding bands are arranged alternately and parallel to each other when the louver film is viewed in a plane from the curved surface side, and in a cross section of the louver film cut by a virtual plane perpendicular to the longitudinal direction of the light transmission bands in the planar view, center lines of the plurality of light-shielding bands extending in the thickness direction of the louver film are approximately parallel to each other, and the light transmission bands and the light-shielding bands contain an elastomer. [2] The light transmission direction control body according to [1], wherein the rubber hardness of the elastomer is 60° or more and 80° or less. [3] The light transmission direction control body according to [1] or [2], further comprising a transparent protective layer on one or both sides of the louver film. [4] The light transmission direction control body according to any one of [1] to [3], wherein the curved surface has a plurality of different radii of curvature. [5] The light transmission direction control element according to any one of [1] to [4], wherein the curved surface has at least one inflection point. [6] The light transmission direction control body according to any of [1] to [5], wherein the adherend is a display unit that displays an image on a display device, the curved surface is a display surface of the display unit, and when the light transmission direction control body is mounted on a vehicle, the plurality of light transmission bands and the plurality of light-shielding bands each extend such that their thickness direction is perpendicular to the display surface and their longitudinal directions extend along one direction of the display surface, the plurality of light transmission bands and the plurality of light-shielding bands form optical paths through which light of the image displayed by the display unit passes, and when the louver film is attached to the display surface, the directions of the optical axes of the optical paths are the same in vertical cross sections of the optical paths.

[0009] [7] A method for manufacturing a louver film to be provided on a light transmission direction control body according to any one of [1] to [6], comprising: a block body forming step of forming a block body by alternately laminating a plurality of sheets for a light transmission band and a sheet for a light shielding band; and a cutting step of forming a louver film by cutting the block body, wherein in the cutting step, the block body is cut so that the cut surface of the block body after cutting out the louver film has substantially the same curved surface as the curved surface of the adherend.

[0010] [8] A method for producing a light transmission direction control body according to any one of [1] to [6], comprising a step of attaching the louver film obtained by the louver film production method according to [7] to a curved surface of the adherend. Effect of the Invention

[0011] According to the present invention, it is possible to provide a light transmission direction control body that can parallelize light exiting a curved surface (align the direction of light), a method for manufacturing a louver film to be provided on the light transmission direction control body, and a method for manufacturing a light transmission direction control body. [Brief description of the drawings]

[0012] [Figure 1] 1 is a plan view showing a light transmission direction control body according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1, showing another example of a light transmission direction control body according to an embodiment of the present invention. FIG. [Figure 4] FIG. 2 is a perspective view showing a cutting step in a manufacturing method of a louver film provided on a light transmission direction control body according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] (Light transmission direction control body) A light transmission direction control body according to one embodiment of the present invention will be described. Fig. 1 is a plan view showing the light transmission direction control body of the present embodiment, and Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. The light transmission direction control body 1 of this embodiment includes a transparent adherend having a curved surface a, and a louver film 20 attached to the curved surface a of the adherend . The adherend 10 is, for example, a light-transmitting (transparent) substrate arranged on the surface (light-emitting surface) side of a light source that emits surface light from electroluminescence (EL) or light-emitting diodes (LEDs) through a diffusion plate or light guide. Specifically, examples of the adherend 10 include a substrate (diffusion plate) arranged on the surface (light-emitting surface) side of a light source in a lighting device, and a substrate arranged on the display surface side of a display unit that displays an image in a display device. Therefore, the louver film 20 is arranged on the surface (light-emitting surface) side of a light source such as a light-emitting diode (LED) through the adherend 10.

[0014] In this embodiment, as shown in FIG. 1, the louver film 20 has a rectangular shape in a plan view. In this embodiment, the longitudinal direction of the light transmission direction control body 1 (louver film 20) is the X direction (the left-right direction on the paper in Figures 1 and 2), the short direction of the light transmission direction control body 1 (louver film 20) (the up-down direction on the paper in Figure 1) is the Y direction, and the vertical direction of the surface of the light transmission direction control body 1 (louver film 20) (i.e., the thickness direction of the light transmission direction control body 1 (louver film 20)) is the Z direction.

[0015] In the present embodiment, the rectangle may have a rectangular outline. For example, at least one of the right-angled corners of the rectangle may be rounded. A notch may be formed in any part of the periphery of the rectangle, or a protruding portion may be formed that partially protrudes from a side of the rectangle. The side of the rectangle may be partially non-linear (for example, curved, zigzag, etc.).

[0016] In the present embodiment, the louver film 20 is rectangular in plan view as shown in Fig. 1, but the present invention is not limited to this. In the present invention, the louver film may be circular, elliptical, irregular, etc. in plan view.

[0017] In this embodiment, as shown in FIG. 1, the louver film 20 has a plurality of light transmission zones 21 and a plurality of light shielding zones 22. The light transmission zones 21 and the light shielding zones 22 are alternately arranged in parallel when the louver film 20 is viewed in plan from the curved surface 10a side of the adherend 10. Also, as shown in FIG. 2, in a cross section of the louver film 20 cut by a virtual plane perpendicular to the longitudinal direction of the light transmission zones 22 (Y direction in FIG. 1) in a plan view, the center lines of the plurality of light shielding zones 22 extending in the thickness direction of the louver film 20 (Z direction in FIG. 1) are approximately parallel to each other. In other words, as shown in FIG. 2, in a cross section perpendicular to the plurality of light transmission zones 21 and the plurality of light shielding zones 22 parallel to each other in a plan view of the louver film 20, the center lines of the plurality of light shielding zones 22 extending in the thickness direction of the louver film 20 (Z direction in FIG. 1) are approximately parallel to each other. In this embodiment, as shown in FIG. 2, the plurality of light shielding zones 22 are approximately parallel to each other in the Z direction. In this embodiment, "approximately parallel" means that multiple light-shielding bands 22 are arranged such that, for an angle α of one light-shielding band 22 with respect to the cross-sectional direction of the louver film 20 cut by a virtual plane perpendicular to the longitudinal direction of the light-transmitting bands 22 (Y direction in Figure 1) in a planar view, the angle β of each of the other light-shielding bands 22 with respect to the cross-sectional direction is in the range of angle α±10° or less.

[0018] The angle of the light-shielding zone 22 with respect to the cross-sectional direction of the louver film 20, cut by a virtual plane perpendicular to the longitudinal direction of the light-transmitting zone 22 in a planar view, can be measured using a measuring microscope equipped with an angle measurement function as the acute angle between a center line drawn in the direction from the light-incident side to the light-exiting side of the light-shielding zone 22 and the perpendicular direction to the curved surface 10a of the substrate 10, using the surface of the light-exiting side of the louver film 20 as a reference in the light transmission direction control body 1. The angle of the light-shielding zone 22 is determined by measuring the installation angles of five light-shielding zones 22 that are randomly selected, for example, by the above-mentioned angle measuring method, and averaging the obtained values.

[0019] The light transmittance of the entire light transmission direction controlling body 1 is preferably 45% or more, and more preferably 55% or more. Specifically, the light transmittance is preferably 45% or more and 100% or less, and more preferably 55% or more and 100% or less. The light transmittance of the entire light transmission direction controlling body 1 is a value measured by the following method at an angle at which the transmittance of the light transmission direction controlling body 1 is maximum. The light transmittance of the entire light transmission direction controlling body 1 is the average value of five randomly selected points on the light transmission direction controlling body 1. In this specification, the light transmittance value is defined as the value calculated by the formula Light transmittance = (B / A) x 100 (unit: %) in an apparatus that uses D65 as a light source defined in JIS Z 8720 and measures the intensity of inspection light emitted from a light source with a light receiving sensor, where A is the output value of the light receiving sensor when there is no object to be measured on the optical path of the inspection light, and B is the output value when an object to be measured is set on the optical path of the inspection light and the transmitted light that has passed through the object to be measured is received by the light receiving sensor.

[0020] The lengths of the light transmission direction control body 1 in the longitudinal and lateral directions are not limited and are adjusted appropriately according to the size of the surface (light exit surface) of the light source.

[0021] (adherent) The adherend 10 is a light-transmitting member disposed on the outermost surface of a light-emitting device (including a display device and a lighting device), and preferably has a light transmittance of 75% or more, and more preferably 85% or more, when light is incident along the thickness direction. Specifically, the light transmittance is preferably 75% or more and 100% or less, and more preferably 85% or more and 100% or less. In addition, when the adherend 10 is a diffusion plate of a lighting device, the light transmittance according to JIS K 7361 is preferably 45% or more.

[0022] Examples of materials constituting the adherend 10 include polycarbonate resins, polyester resins, acrylic resins, polyolefin resins (particularly, cycloolefin polymers), cellulose resins, polyimide resins, polyamide resins, epoxy resins, glass, etc. These materials may be used alone or in combination of two or more.

[0023] The curved surface 10a of the adherend 10 may have a plurality of different radii of curvature (R). The radius of curvature (R) of the curved surface 10a of the adherend 10 is preferably 100 mm or more, and more preferably 200 mm or more. Specifically, the radius of curvature (R) is preferably 100 mm or more and 3000 mm or less, and more preferably 200 mm or more and 2000 mm or less.

[0024] The curved surface 10a of the adherend 10 preferably has at least one inflection point. Specifically, as shown in FIG.

[0025] (Louver film) The louver film 20 includes a plurality of linear light transmission zones 21 and a plurality of linear light shielding zones 22, and the light transmission zones 21 and the light shielding zones 22 are arranged alternately and repeatedly. In this embodiment, the light transmission zones 21 and the light shielding zones 22 are formed along the Y direction. In this embodiment, the width of each light transmission zone 21 and the width of each light shielding zone 22 are both constant in their length direction. The term "constant" here includes a range of ±5% of the design value of the width. In addition, the widths of all light transmission zones 21 are the same, and the widths of all light shielding zones 22 are the same. However, the "same" width in the present invention allows for slight differences. In the light transmission zones 21, the "same" width also includes a range of ±10% of the width of the light transmission zone 21 located at the center, and in the light shielding zones 22, the "same" width also includes a range of ±10% of the width of the light shielding zone 22 located at the center. In addition, the "width" refers to the length in the X direction of the light transmission zone 21 or the light shielding zone 22 on the light exit side surface of the louver film 20.

[0026] In the louver film 20, from the viewpoint of controlling the directivity of light transmitted through the louver film 20 in any direction, the average width of the plurality of light transmission zones 21 is preferably 50 μm or more and 200 μm or less, and more preferably 100 μm or more and 150 μm or less. For the same reason, the average width of the plurality of light shielding zones 22 is preferably 1 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less. The width of each of the light transmission zones 21 is preferably 50 μm or more and 200 μm or less, and more preferably 100 μm or more and 150 μm or less. For the same reason, the width of each of the light shielding zones 22 is preferably 1 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less.

[0027] In this embodiment, the thickness of the louver film 20 is constant. "Constant" here includes a range of within ±5% of the design thickness value. Furthermore, "thickness" refers to the length of the louver film 20 in the Z direction. The thickness of the louver film 20 can be obtained by measuring a cross-sectional photograph of the louver film 20 alone, and is the average value of values ​​obtained by measuring at 10 or more locations. The thickness of the louver film 20 is preferably 100 μm or more and 5000 μm or less, more preferably 120 μm or more and 1000 μm or less, and even more preferably 150 μm or more and 500 μm or less. If the thickness of the louver film 20 is within the above range, the directivity of the light transmitted through the louver film 20 can be easily adjusted, and the louver film 20 can be easily manufactured.

[0028] The light transmittance throughout the entire louver film 20 is preferably 45% or more, and more preferably 55% or more. Specifically, the light transmittance is preferably 45% or more and 100% or less, and more preferably 55% or more and 100% or less. The light transmittance throughout the entire louver film 20 is the average value of five randomly selected locations on the louver film 20.

[0029] [Light transmission band] An elastomer that transmits the desired wavelength of visible light is used as the material constituting the light transmission band 21. The wavelength of light that transmits through the light transmission band 21 may be the entire range of visible light, 380 nm or more and 830 nm or less, or may be a part of it. The rubber hardness of the elastomer is preferably 60° or more and 80° or less. The rubber hardness of the elastomer in this embodiment is a value measured by a type A durometer in accordance with JIS K 6253-2:2012 "Vulcanized rubber and thermoplastic rubber - Determination of hardness - Part 2: International rubber hardness (10IRHD to 100IRHD)".

[0030] The elastomer constituting the light transmission band 21 may be a thermoplastic elastomer or a thermosetting elastomer having high transparency. Examples of the thermoplastic elastomer include polystyrene resin, polyolefin resin, polyvinyl chloride resin, polyurethane resin, polyester resin, and polyamide resin. Examples of the thermosetting elastomer include urethane resin, fluorine resin, and silicone resin. Among these, silicone resin is preferred, and silicone rubber is more preferred in terms of its high flexibility, heat resistance, and transparency.

[0031] Examples of silicone rubbers include a silicone rubber composition generally known as millable rubber, which consists of a diorganopolysiloxane whose molecular chain ends are blocked with hydroxysilyl groups or vinylsilyl groups and an organic peroxide; and a so-called addition reaction type organosilicone rubber composition, which consists of a diorganopolysiloxane having at least two vinyl groups bonded to silicon atoms in the molecule, an organohydrogenpolysiloxane having at least three hydrogen atoms bonded to silicon atoms (i.e., SiH bonds) in the molecule, and a platinum catalyst. The light transmission band 21 preferably has a light transmittance of 75% or more, and more preferably 85% or more, when light is incident only on the light transmission band 21 along the Z direction. Specifically, the light transmittance is preferably 75% or more and 100% or less, and more preferably 85% or more and 100% or less.

[0032] [Shade strip] The material constituting the light shielding band 22 is a colored resin containing an elastomer as a base material and a coloring agent such as a pigment or dye added to the elastomer. The elastomer contained in the light shielding band 22 can be the same as the elastomer contained in the light transmission band 21. The elastomer contained in the light shielding band 22 may be the same as the elastomer contained in the light transmission band 21, or may be different. From the viewpoint of increasing the adhesiveness between the light transmission band 21 and the light shielding band 22, it is preferable that the elastomer contained in the light shielding band 22 is the same as the elastomer contained in the light transmission band 21.

[0033] The color tone of the light shielding zone 22 may be, for example, black, red, yellow, green, blue, light blue, etc., as long as the light shielding zone 22 has a preferable light shielding property. The color tone of the light shielding zone 22 can be adjusted by the type and amount of colorant added. Since the color tone of the light shielding zone 22 constitutes the color tone recognized when the louver film 20 is viewed, it is preferable to design the light shielding zone 22 while taking into consideration the design of the light transmission direction control body 1.

[0034] The light shielding zone 22 preferably has a light transmittance of 10% or less, and more preferably 5% or less, when light is incident only on the light shielding zone 22 along the Z direction. Specifically, the light transmittance is preferably 0% or more and 10% or less, and more preferably 0% or more and 5% or less. Such a light transmittance provides sufficient light shielding properties.

[0035] Specific examples of the colorant contained in the light shielding zone 22 include common organic or inorganic pigments such as carbon black, iron oxide, titanium oxide, yellow iron oxide, disazo yellow, phthalocyanine blue, etc. The colorant may be used alone or in combination of two or more kinds. When a black pigment is not used as a colorant, it is preferable to use a white pigment in combination in order to ensure light-shielding properties.

[0036] In the light transmission direction control body 1 of this embodiment, in a cross section perpendicular to the plurality of light transmission zones 21 and the plurality of light shielding zones 22, which are parallel in a plan view of the louver film 20 attached to the curved surface 10a of the adherend 10, the plurality of light shielding zones 22 are approximately parallel, and the light transmission zones 21 and the light shielding zones 22 contain an elastomer. Therefore, the louver film 20 can deform following the shape of the curved surface 10a of the adherend 10 and can be closely attached to the curved surface 10a of the adherend 10. In addition, the louver film 20 can make the light emitted from the curved surface 10a of the adherend 10 parallel (align the direction of the light). In other words, the louver film 20 can irradiate the light emitted from the curved surface 10a of the adherend 10 in one direction.

[0037] The reason why the louver film 20 deforms to conform to the shape of the curved surface 10a of the adherend 10 will be described in detail. As described later, the louver film 20 is, for example, a block body in which a plurality of light transmission band sheets and a plurality of light shielding band sheets are alternately laminated one by one, cut so that the cut surface is substantially the same curved surface as the curved surface 10a of the adherend 10. The louver film 20 is a low-elastic body. Therefore, when the louver film 20 cut into a curved shape is placed on a plane, the cut surface of the louver film 20 becomes flat due to its own weight. Since this louver film 20 can be attached to the adherend 10 in a flat state, the light transmission direction control body 1 can be manufactured with a good yield. In the flat louver film 20, the light transmission band 21 and the plurality of light shielding bands 22 are inclined obliquely with respect to the thickness direction of the louver film 20. When such a flat louver film 20 is attached to the curved surface 10a of the substrate 10, the side of the louver film 20 facing the curved surface 10a shrinks and the side of the louver film 20 facing away from the curved surface 10a expands, thereby making it possible to collimate the light emerging from the curved surface 10a of the substrate 10.

[0038] In the present embodiment, the light transmission direction control body 1 does not include a transparent protective layer, but the present invention is not limited to this. In the present invention, as shown in FIG. 3, the louver film 20 may include a transparent protective layer 30 on one side (one side (the surface from which the light transmitted through the louver film 20 is emitted (the surface on the light emission side)) 20a or the other side (the surface opposite to the surface on the light emission side of the louver film 20) 20b) or both sides (one side 20a and the other side 20b). The other surface 20b of the louver film 20 is adhered to the adherend 10 and is not exposed, so it will not be damaged. Therefore, a transparent protective layer may not be provided on the surface 20b of the louver film 20 into which the light is incident.

[0039] The transparent protective layer 30 has a light transmittance of preferably 75% or more, and more preferably 85% or more, when light is incident along the thickness direction. Specifically, the light transmittance is preferably 75% or more and 100% or less, and more preferably 85% or more and 100% or less.

[0040] Examples of the transparent resin material constituting the transparent protective layer 30 include polycarbonate resin, polyester resin, acrylic resin, polyolefin resin (particularly, cycloolefin polymer), cellulose resin, etc. Among these transparent resin materials, polycarbonate or polyester resin is preferred because of its high transparency and heat resistance. The transparent resin material may be used alone or in combination of two or more kinds.

[0041] The thickness of the transparent protective layer 30 is preferably 0.01 mm or more and 0.3 mm or less, and more preferably 0.1 mm or more and 0.2 mm or less. If the thickness of the transparent protective layer 30 is equal to or more than the lower limit, the louver film 20 can be sufficiently protected, and if the thickness is equal to or less than the upper limit, sufficient light transmittance can be ensured.

[0042] An example of a method for laminating the transparent protective layer 30 is a method in which the material constituting the transparent protective layer 30 is formed into a sheet in advance, and the obtained transparent sheet is attached to one side 20a of the louver film 20. When attaching the transparent sheet, an adhesive may be used, or thermocompression bonding may be performed without using an adhesive.

[0043] When an adhesive is used, it is preferable that the adhesive has a high light transmittance after curing. Specifically, the adhesive layer alone has a light transmittance of preferably 65% ​​or more, more preferably 80% or more after curing. Specifically, the light transmittance is preferably 65% ​​or more and 100% or less, and more preferably 80% or more and 100% or less.

[0044] Examples of such adhesives include urethane adhesives, acrylic adhesives, polyester adhesives, silicone adhesives, etc. The adhesive may be any of a thermosetting adhesive, a multi-liquid reaction adhesive, an ultraviolet curing adhesive, etc.

[0045] The adhesive layer that bonds the louver film 20 and the transparent protective layer 30 is also required to be easily deformed. The rubber hardness of the adhesive layer after curing is preferably 20° or more and 80° or less, and more preferably 30° or more and 70° or less. If the rubber hardness is less than 20°, the adhesive layer will become gel-like. If the rubber hardness is more than 80°, the adhesive layer will be difficult to deform.

[0046] The thickness of the adhesive layer is preferably 5 μm or more and 40 μm or less, and more preferably 10 μm or more and 30 μm or less.

[0047] A case will be described in which the adherend 10 is a display section for displaying an image on a display device, in which the curved surface 10a of the adherend 10 is the display surface of the display section of the display device. For example, when the light transmission direction control body 1 is mounted on a vehicle, the light transmission direction control body 1 is arranged such that the thickness direction of each of the light transmission bands 21 and the light shielding bands 22 extends in a direction perpendicular to the display surface (curved surface 10a) and the longitudinal direction of each of the light transmission bands 21 and the light shielding bands 22 extends along one direction of the display surface. As a result, the light transmission bands 21 and the light shielding bands 22 form an optical path through which the light of the image displayed by the display unit passes. In addition, when the louver film 20 is attached to the display surface, the direction of the optical axis of the optical path is the same in the vertical cross section of the optical path.

[0048] (Louver film manufacturing method) The louver film 20 provided in the light transmission direction control body 1 of this embodiment can be manufactured by a manufacturing method including a block body forming step and a cutting step of cutting the block body to form a louver film. The manufacturing method of the louver film of this embodiment may also include a laminate forming step. Furthermore, the manufacturing method of the louver film of this embodiment may also include a transparent protective layer laminating step.

[0049] [Laminate formation process] The laminate formation step is a step of alternately laminating a plurality of sheets for the light transmitting band and a plurality of sheets for the light shielding band to form a laminate. The sheet for the light transmission band can be manufactured by forming the elastomer constituting the light transmission band 21 into a sheet. The sheet for the light shielding band can be manufactured by forming the elastomer and colored resin containing a colorant constituting the light shielding band 22 into a sheet. The sheet for the light transmission band and the sheet for the light shielding band are each molded to a constant thickness. Examples of the molding method for molding the elastomer and colored resin into a sheet include extrusion molding, calendar molding, and press molding.

[0050] In forming the laminate, a plurality of sheets for the light transmission band and a plurality of sheets for the light shading band may be alternately stacked one by one to form the laminate, or a plurality of laminate units each having a plurality of sheets for the light transmission band and a plurality of sheets for the light shading band stacked alternately may be prepared in advance and then stacked. The sheet for the light transmitting band and the sheet for the light shielding band may be bonded together using an adhesive.

[0051] [Block body forming process] The block body forming step is a step of forming a block body by pressing a laminate in which a plurality of sheets for a light transmitting band and a plurality of sheets for a light shielding band are alternately laminated one by one. The laminate can be pressed using, for example, a roll or a press. When pressing, it is preferable to heat the sheets in order to increase the adhesive strength between the sheets. The heating temperature is appropriately selected depending on the material used. If the heating temperature is too high, the uniformity of the sheet thickness may be lost, and if the heating temperature is too low, the adhesive strength between the sheets may be weakened.

[0052] [Cutting process] The cutting step is a step of cutting the block body so that the cut surface of the block body after cutting out the louver film 20 is substantially the same curved surface as the curved surface 10a of the adherend 10. In other words, the cutting step is a step of cutting the block body by setting a cutting angle so that the center lines extending in the thickness direction of the louver film 20 of the multiple light-shielding zones 22 are substantially parallel to each other in a cross section of the louver film 20 cut along a virtual plane perpendicular to the longitudinal direction of the light-transmitting zones 22 in a plan view. In the cutting step in this embodiment, as shown in FIG. 2, for example, the block body 100 is cut so as to form a curved cut surface with a gradually changing cutting angle, thereby cutting out the sheet-like louver film 20.

[0053] As a cutting method, a cutting blade can be inserted into one surface of the block body 100 where only the sheet 110 for the light transmission band or only the sheet 120 for the light shielding band is exposed, and the cutting blade or the block body 100 is moved so that the cut surface is curved, thereby cutting the sheet 110 for the light transmission band and the sheet 120 for the light shielding band alternately. Another cutting method is, for example, a method in which a curved cutting blade is inserted into one surface of the block body 100 where both the light transmission band sheet 110 and the light shielding band sheet 120 are exposed, so as to obtain a desired curved cut surface, thereby simultaneously cutting the light transmission band sheet 110 and the light shielding band sheet 120. Here, a cutting blade having a curved surface substantially identical to the curved surface 10a of the adherend 10 is used.

[0054] [Transparent protective layer lamination process] The transparent protective layer lamination process is a process of laminating a transparent protective layer (not shown) on one side (one side 20a or the other side 20b) or both sides 20a (one side 20a and the other side 20b) of the louver film 20 obtained by the cutting process.

[0055] An example of a method for laminating the transparent protective layer is a method in which the material constituting the transparent protective layer is formed into a sheet in advance, and the obtained transparent sheet is attached to at least one surface 20a of the louver film 20. When attaching the transparent sheet, an adhesive may be used, or it may be thermocompression-bonded without using an adhesive.

[0056] When an adhesive is used, it is preferable that the adhesive has a high light transmittance after curing. Specifically, the adhesive layer alone has a light transmittance of preferably 65% ​​or more, more preferably 80% or more after curing. Specifically, the light transmittance is preferably 65% ​​or more and 100% or less, and more preferably 80% or more and 100% or less.

[0057] Examples of such adhesives include epoxy adhesives, urethane adhesives, acrylic adhesives, melamine adhesives, polyester adhesives, silicone adhesives, etc. The adhesive may be any of a thermosetting adhesive, a multi-liquid reaction adhesive, an ultraviolet curing adhesive, etc.

[0058] In this embodiment, in the transparent protective layer lamination step, a transparent protective layer may also be laminated on the other surface 20b of the louver film 20 obtained in the cutting step. The method for laminating the transparent protective layer is as described above.

[0059] (Method of manufacturing light transmission direction control body) The light transmission direction control body 1 of this embodiment can be manufactured by a manufacturing method that includes a louver film attachment step.

[0060] [Louver film attachment process] The louver film attachment step is a step of attaching the louver film 20 obtained by the louver film manufacturing method of this embodiment or the louver film 20 laminated with a transparent protective layer to the curved surface 10a of the adherend 10. In other words, it is a step of attaching the louver film 20 obtained by cutting out the block body 100 in the cutting step of the louver film manufacturing method of this embodiment to the curved surface 10a of the adherend 10 so that the cut surface has substantially the same curve as the curved surface 10a of the adherend 10.

[0061] When attaching the louver film 20 to the curved surface 10a of the adherend 10, an adhesive may be used, or the louver film 20 may be attached by thermocompression without using an adhesive.

[0062] When an adhesive is used, the same adhesive as that used in the transparent protective layer lamination step of the manufacturing method of the louver film of this embodiment is used.

[0063] By the above steps, the light transmission direction control element 1 of the present embodiment shown in FIG. 1 and FIG. 2 is obtained. [Industrial Applicability]

[0064] In the light transmission direction control body of the present invention, in a cross section of the louver film cut by a virtual plane perpendicular to the longitudinal direction of the light transmission band when viewed in a plan view from the curved side of the louver film, the center lines extending in the thickness direction of the louver film of the multiple light-shielding bands are approximately parallel to each other, so that the light exiting from the curved surface of the adherend can be made parallel (the direction of the light can be aligned). [Explanation of symbols]

[0065] 1. Light transmission direction control body 10 Adherent 20 Louver Film 21 Light transmission zone 22 Shade Zone 30 Transparent protective layer

Claims

1. A light transmission direction control body comprising: a light-transmitting adherend having a curved surface; a louver film attached to the curved surface; and a transparent protective layer laminated on one or both sides of the louver film via an adhesive layer, The curved surface of the adherend has at least one inflection point, The louver film has a plurality of light transmitting zones and a plurality of light blocking zones alternately arranged parallel to each other along the curved surface, In a cross section along a thickness direction of the louver film, each of the plurality of light-shielding zones is exposed on a front surface and a back surface of the louver film, the light transmitting zone and the light blocking zone contain an elastomer, the elastomer being silicone rubber; The rubber hardness of the elastomer is 60° or more and 80° or less, A light transmission direction control body, wherein the adhesive layer after curing has a rubber hardness of 20° or more and 80° or less.

2. The light transmission direction control element of claim 1 , wherein the curved surface has a plurality of different radii of curvature.

3. the adherend is a display unit that displays an image on a display device, the curved surface is a display surface of the display unit, The light transmission direction control body according to claim 1 , wherein the plurality of light transmission zones and the plurality of light blocking zones form an optical path through which light of the image displayed by the display portion passes.

4. A method for producing a louver film to be provided on the light transmission direction control body according to any one of claims 1 to 3, comprising the steps of: The method includes a block body forming step of alternately laminating a plurality of sheets for a light transmitting band and a plurality of sheets for a light shielding band to form a block body, a cutting step of cutting the block body to form a louver film, and a step of laminating a transparent protective layer on one or both sides of the louver film via an adhesive layer, In the cutting step, the block body is cut so that a cut surface of the block body after cutting out the louver film has substantially the same curved surface as a curved surface of the adherend, The rubber hardness of the elastomer is 60° or more and 80° or less, A method for producing a louver film, wherein the adhesive layer has a rubber hardness of 20° or more and 80° or less after curing.

5. A method for producing a light transmission direction control body according to any one of claims 1 to 3, comprising the steps of: A method for producing a light transmission direction control member, comprising a step of attaching the louver film obtained by the method for producing a louver film according to claim 4 to the curved surface of the adherend.

Images