Laminate film

Abstract

To provide a laminate film having high incident efficiency of light from a light source even when a thickness of the laminate film is made thin.SOLUTION: The laminate film having a plurality of layers laminated has: an end face along a laminating direction; a light incident surface crossing the end face for making light from the light source incident; a light guide layer for guiding the light incident through the light incident surface; and a light extraction layer including a light extraction part capable of extracting the light guided by the light guide layer. A thickness between a first face as a surface of the light extraction layer on the opposite side to the side where the light guide layer is arranged, and a second face as a surface of the light guide layer on the opposite side to the side where the light extraction layer is arranged is 1,000 μm or smaller.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminated film. [Background technology]

[0002] A method has been proposed for realizing lighting and displays with high design value or entertainment value by arranging laminated films on glass, windows, walls, floors, ceilings, etc.

[0003] For example, Patent Document 1 discloses a configuration including a light guide layer having a light receiving side surface that receives light emitted from a light source, and a light distribution control structure for light propagating within the light guide layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2022 / 025067 Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the thickness of the laminated film is reduced, the configuration of Patent Document 1 allows light from the light source to enter the light guide layer only from the end portion, such as the side surface, of the light guide layer, leaving room for improvement in terms of incidence efficiency.

[0006] An object of the present invention is to provide a laminated film that has a high incidence efficiency of light from a light source even when the thickness of the laminated film is reduced. [Means for solving the problem]

[0007] The laminated film according to one embodiment of the present invention is a laminated film in which a plurality of layers are laminated, and has an end face along the stacking direction, a light incident surface that intersects the end face and allows light from a light source to be incident, a light guide layer that guides the light incident through the light incident surface, and a light extraction layer including a light extraction portion capable of extracting light guided by the light guide layer, and the thickness between a first surface, which is the surface of the light extraction layer on the side opposite to the side on which the light guide layer is arranged, and a second surface, which is the surface of the light guide layer on the side opposite to the side on which the light extraction layer is arranged, is 1000 μm or less. Effect of the Invention

[0008] According to the present invention, it is possible to provide a laminate film having a high incidence efficiency of light from a light source even when the thickness of the laminate film is reduced. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional view of a laminated film according to an embodiment. [Diagram 2] FIG. 2 is a schematic plan view of a light extraction layer according to an embodiment. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 2 is a schematic cross-sectional view of a light extraction portion according to an embodiment. [Diagram 5] FIG. 4 is a schematic cross-sectional view of a laminated film according to a first modified example. [Figure 6] FIG. 11 is a schematic cross-sectional view of a laminated film according to a second modified example. [Figure 7] FIG. 13 is a schematic cross-sectional view of a laminated film according to a third modified example. [Figure 8] FIG. 13 is a schematic cross-sectional view of a laminated film according to a fourth modified example. [Figure 9] FIG. 13 is a schematic cross-sectional view of a laminated film according to a fifth modified example. [Figure 10] FIG. 13 is a schematic cross-sectional view of a laminated film according to a sixth modified example. [Figure 11] FIG. 13 is a schematic cross-sectional view of a laminated film according to a seventh modified example. [Figure 12] FIG. 13 is a schematic cross-sectional view of a laminated film according to an eighth modified example. [Figure 13] FIG. 13 is a schematic cross-sectional view of a laminated film according to a ninth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In each drawing, the same components are given the same reference numerals, and duplicated explanations will be omitted as appropriate.

[0011] The following embodiments are illustrative of a laminated film for embodying the technical concept of the present invention, and the present invention is not limited to the following embodiments. The dimensions, materials, shapes, and relative positions of the components described below are intended to be illustrative, and are not intended to limit the scope of the present invention, unless otherwise specified. In addition, the sizes and positional relationships of the components shown in the drawings may be exaggerated to clarify the explanation.

[0012] In the drawings shown below, a Cartesian coordinate system having an X-axis, a Y-axis, and a Z-axis is used to express directions. The X-axis, the Y-axis, and the Z-axis are approximately perpendicular to each other. The direction in which the X-axis arrow points is expressed as the +X direction or +X side, and the direction opposite to the +X direction is expressed as the -X direction or -X side. The direction in which the Y-axis arrow points is expressed as the +Y direction or +Y side, and the direction opposite to the +Y direction is expressed as the -Y direction or -Y side. The direction in which the Z-axis arrow points is expressed as the +Z direction or +Z side, and the direction opposite to the +Z direction is expressed as the -Z direction or -Z side.

[0013] The Z direction along the Z axis indicates the stacking direction of each layer constituting the laminated film according to the embodiment. In this specification, "planar view" refers to viewing an object from the Z direction. The +Z direction is referred to as "upper", and the -Z direction is referred to as "lower". However, these directional expressions do not limit the directions of the embodiment. In this specification, "thickness" refers to the length of an object in the Z direction, i.e., the stacking direction of each layer. The cross-sectional view shows a cross section parallel to the YZ plane of the laminated film according to the embodiment.

[0014] [Embodiment] <Example of Overall Configuration of Laminate Film 10 According to the Embodiment> Fig. 1 is a cross-sectional view showing a schematic example of a laminated film 10 according to a first embodiment. In the example shown in Fig. 1, the laminated film 10 is a laminated film in which a plurality of layers are laminated. The laminated film 10 has an end surface 103 along the lamination direction (Z direction), a light incident surface 1b that intersects with the end surface 103 and allows light L from a light source 50 to enter, a light guide layer 1 that guides the light L incident through the light incident surface 1b, and a light extraction layer 2 that includes a light extraction portion 21 that can extract the light L guided by the light guide layer 1.

[0015] The light source 50 is, for example, an LED (Light Emitting Diode) light source. Light L from the light source 50 enters the light guide layer 1 through a light incident surface 1b located in a region of the light guide layer 1 where the light extraction layer 2 and the light guide layer 1 do not overlap in a plan view. In the example shown in Fig. 1, the region of the light incident surface 1b is a region of the upper surface 104 of the light guide layer 1 that is defined by an end 1a of the light guide layer 1 and an end 2a of the light extraction layer 2.

[0016] The inclination angle of the light source 50 arranged on the light incident surface 1b with respect to the light guide layer 1 may be any angle as long as the light L from the light source 50 is incident on the light incident surface 1b into the light guide layer 1 and can be guided within the light guide layer 1. The light source 50 is fixed by an adhesive member or the like to a structure in the periphery of the laminated film 10, such as an adherend on which the laminated film 10 is arranged.

[0017] The laminated film 10 guides the light L incident from the light source 50 through the light guide layer 1, and extracts the light L from inside the light guide layer 1 to the outside through the light extraction section 21. The laminated film 10 can illuminate the space in which the laminated film 10 is placed by the light L extracted from the light guide layer 1. The laminated film 10 can be placed on an adherend such as glass, a window, a wall, a floor, or a ceiling. The laminated film 10 can also be used as a flexible lighting film without being placed on an adherend. For example, the laminated film 10 is placed by being attached to the surface of the adherend. The laminated film 10 can illuminate an indoor space or the like when placed on an adherend such as window glass.

[0018] In this embodiment, the thickness t1 between the first surface 101 and the second surface 102 is 1000 μm or less. The first surface 101 is the surface of the light extraction layer 2 on the opposite side to the side where the light guide layer 1 is arranged. The second surface 102 is the surface of the light guide layer 1 on the opposite side to the side where the light extraction layer 2 is arranged. For example, the thickness t1 between the first surface 101 and the second surface 102 can be 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, 400 μm or less, or 300 μm or less. The lower limit is not particularly limited, but is, for example, 50 μm or more, 100 μm or more, or 200 μm or more. By having the thickness t1 of 1000 μm or less, the laminated film 10 can reduce its own presence and make the laminated film 10 less noticeable. It can also be used as a film that emits light and has flexibility. In the present embodiment, it is possible to provide a laminate film 10 with high designability by reducing the presence of the laminate film 10. Furthermore, the laminate film 10 can improve the designability of an adherend on which the laminate film 10 is disposed.

[0019] Here, when light from a light source is incident on the light guide layer from the end of the laminated film, the area of ​​the end of the light guide layer is small, so the efficiency of light incident on the inside of the laminated film may be low. As the thickness of the laminated film becomes thinner, the area of ​​the end of the laminated film from the light source becomes narrower, making it difficult for light to enter the inside of the laminated film from the end, and the above-mentioned incidence efficiency becomes lower. For example, if the thickness of the laminated film is made 1000 μm or less in order to improve the design of the laminated film, the thinness of the laminated film reduces the efficiency of light incident from the light source.

[0020] In the laminated film 10, the end 2a of the light extraction layer 2 can be located inside the light guide layer 1 more than the end 1a of the light guide layer 1 in plan view. For example, the distance between the end 2a of the light extraction layer 2 and the end 1a of the light guide layer 1 is 1 mm or more and 100 mm or less. The inside in plan view means the side closer to the center of the laminated film 10 when the laminated film 10 is viewed in plan view. The laminated film 10 allows the light L from the light source 50 to be incident on the light guide layer 1 through the light incident surface 1b located in the region of the light guide layer 1 where the light extraction layer 2 and the light guide layer 1 do not overlap. For example, by making the area of ​​the light incident surface 1b larger than the area of ​​the end 2a of the light guide layer 1, the incidence efficiency of the light L into the laminated film 10 can be increased compared to the case where the light L is incident from the end 2a of the light guide layer 1. As described above, in this embodiment, even if the thickness of the laminated film 10 is reduced, a laminated film 10 having a high incidence efficiency of the light L from the light source 50 can be provided.

[0021] In the laminated film 10, the thickness t2 of the light guide layer 1 may be set to 30 μm or more. By setting the thickness t2 of the light guide layer 1 to 30 μm or more, the incidence efficiency of the light L from the light source 50 into the laminated film 10 can be increased.

[0022] In addition, in the laminated film 10, the light extraction layer 2 may be disposed on the side of the light guide layer 1 where the light source 50 is disposed. In this configuration, the thickness of the configuration consisting of the laminated film 10 and the light source 50 is the sum of the thickness of the light guide layer 1 and the thickness of the light source 50. On the other hand, when the light extraction layer is disposed on the side opposite to the side where the light source is disposed on the light guide layer, the thickness of the configuration consisting of the laminated film and the light source is the sum of the thickness of the light guide layer, the thickness of the light extraction layer, and the thickness of the light source. Therefore, by disposing the light extraction layer 2 on the side of the light guide layer 1 where the light source 50 is disposed, the thickness of the configuration consisting of the laminated film 10 and the light source 50 can be made thinner than the case where the light extraction layer 2 is disposed on the side opposite to the side where the light source 50 is disposed on the light guide layer 1.

[0023] The laminate film 10 can be made of resin. Being made of resin makes the laminate film 10 highly flexible, and therefore it can be handled in various forms. For example, when the laminate film 10 is formed into a long length, the long laminate film 10 can be wound up, making it easy to handle. However, the laminate film 10 does not necessarily have to be made of resin, and at least a portion of the laminate film 10 may be made of glass or the like.

[0024] The laminated film 10 can have an adhesive layer 3 disposed between the light guide layer 1 and the light extraction layer 2, and adhesively bonding the light guide layer 1 and the light extraction layer 2. In the example shown in Fig. 1, the end face 103 is a surface constituted by the end 2a of the light extraction layer 2 and the end 3a of the adhesive layer 3. However, the adhesive layer 3 is not an essential component, and the light guide layer 1 and the light extraction layer 2 may be bonded together without the adhesive layer 3 being interposed therebetween.

[0025] <Configuration example of light guide layer 1> The light guide layer 1 can be formed from a film having flat surfaces. The material used for the light guide layer 1 is preferably one having a low light absorption coefficient. For example, the material used for the light guide layer 1 can be an acrylic film such as PMMA (Poly Methyl Methacrylate), a cycloolefin film such as COP (Cyclo Olefin Polymer), a polyethylene film such as PET (Polyethylene Terephthalate), a polycarbonate film, or the like.

[0026] From the viewpoint of the efficiency of incidence of light from the light source 50 into the light guide layer 1, the thickness of the light guide layer 1 is preferably 30 μm or more, more preferably 40 μm or more, and even more preferably 60 μm or more or 100 μm or more. On the other hand, from the viewpoint of providing flexibility, the thickness of the light guide layer 1 is preferably 800 μm or less, more preferably 600 μm or less, even more preferably 500 μm or less or less than 500 μm, and particularly preferably 400 μm or less, 300 μm or less, or 200 μm or less. The refractive index of the light guide layer 1 is preferably, for example, 1.45 or more and 1.60 or less.

[0027] <Configuration example of light extraction layer 2> An example of the configuration of the light extraction layer 2 will be described with reference to Fig. 1 and further to Figs. 2 to 4. Fig. 2 is a plan view that shows a schematic view of the light extraction layer 2. Fig. 3 is a cross-sectional view that shows a schematic view of the light extraction layer 2. Fig. 4 is a cross-sectional view that shows a schematic view of the light extraction section 21.

[0028] The light extraction section 21 included in the light extraction layer 2 may be a plurality of internal spaces provided in the light extraction layer 2. Each of the plurality of internal spaces forms an interface that directs light to the +Z side by total internal reflection. The internal space may also be called a cavity. The internal space has a triangular cross-sectional shape (perpendicular to the X direction, parallel to the YZ plane) with an apex angle on the +Z side, and directs the light L propagating in the light guide layer 1 to the +Y side to the +Z side. The light L directed to the +Z side by the internal space is emitted from the laminated film 10. The cross-sectional shape of the internal space is not limited to this, and may be a trapezoid or the like as long as it has an interface that directs the light L propagating in the +Y direction to the +Z side. The direction of light emission can be changed by changing the cross-sectional shape of the internal space (for example, the direction of the apex angle of the triangle).

[0029] The laminated film 10 can extract the light L guided by the light guide layer 1 by the light extraction section 21 and control the light distribution of the extracted light L, so that the visible light transmittance can be 60% or more and the haze value can be less than 10%. In addition, by adjusting the shape and arrangement of the multiple internal spaces in the light extraction section 21, the light distribution, emission efficiency, and luminance distribution of the light L emitted from the laminated film 10 can be controlled. The light extraction section 21 is typically a void portion (air cavity) filled with air. However, the air cavity may be filled with a material having a refractive index lower than that of the light extraction layer 2 instead of air.

[0030] In the light extraction layer 2, a plurality of internal spaces, which are light extraction sections 21, are arranged regularly or randomly along the main surface, i.e., a plane substantially parallel to the XY plane. The size of each internal space can be appropriately selected within a range that can be installed inside the light extraction layer 2. For the light extraction layer 2 containing the light extraction section 21 therein, for example, the light guide layers disclosed in WO 2019 / 182091, WO 2011 / 124765, WO 2019 / 087118, and WO 2011 / 127187 can be used. The entire disclosure of these publications is incorporated herein by reference.

[0031] The light extraction layer 2 is produced, for example, by bonding a first film having no pattern and a second film having a desired fine pattern formed thereon by a lamination method or by using an adhesive (including a pressure-sensitive adhesive).

[0032] The second film may be micropatterned using laser patterning, direct laser imaging, laser drilling, masked or maskless laser or electron beam irradiation, or may be printed, inkjet printed, screen printed, etc. to impart individual properties and modify material or refractive index values. Micro or nano dispensing, dosing, direct "writing", discrete laser sintering, micro-EDM (Electrical Discharge Machining), or micromachining, micromolding, imprinting, embossing, and the like may also be used.

[0033] From the viewpoint of obtaining a good visible light transmittance and haze value of the laminated film 10, the ratio (occupancy rate) of the area of ​​the plurality of internal spaces, which are the light extraction portion 21, to the area of ​​the light extraction layer 2 is preferably 30% or less in plan view. The occupancy rate of the internal spaces may be uniform, or may increase with increasing distance so that the brightness does not decrease even if the distance from the light source 50 increases. The occupancy rate of the internal spaces is preferably uniform. From the viewpoint of obtaining good brightness, the occupancy rate of the internal spaces is preferably 1% or more. The occupancy rate of the internal spaces is preferably 1% or more and 30% or less, and the upper limit is more preferably 25% or less. In order to obtain a high visible light transmittance, it is preferably 10% or less, and more preferably 5% or less.

[0034] The above-mentioned features of the light extraction unit 21 are not limited to the multiple internal spaces formed in the light extraction layer 2 exemplified here, but are common to various light distribution control structures. As a light distribution control structure composed of multiple internal spaces, for example, the light distribution structure described in International Publication No. 2019 / 087118 can be used.

[0035] The light extraction section 21 is not limited to a plurality of internal spaces, and may be a plurality of prisms arranged in the light extraction layer 2. The light extraction layer 2 may be a prism sheet containing a plurality of prisms therein. A plurality of convex portions (prism portions) may be formed directly on the surface of the light extraction layer 2. The refractive index of the light extraction layer 2 is preferably approximately equal to the refractive index of the adhesive layer 3, and the difference (absolute value) between the refractive indices is preferably 0.15 or less, and more preferably 0.1 or less.

[0036] A light distribution control structure in which the light extraction unit 21 is a plurality of internal spaces has a higher light utilization efficiency than a light distribution control structure such as a prism sheet. In addition, the light distribution can be controlled by adjusting the cross-sectional shape (for example, the angles θa and θb of the inclined surfaces in FIG. 4), size, arrangement density, distribution, etc. of the internal space. On the other hand, the visible light transmittance and haze value of the laminated film 10 can be controlled by adjusting the cross-sectional shape, size, arrangement density, and distribution of the plurality of internal spaces of the light extraction unit 21. The visible light transmittance of the laminated film 10 is 60% or more, preferably 65% ​​or more, 70% or more, 75% or more, or 80% or more. The haze value of the laminated film 10 is less than 10%, and can be preferably less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, or less than 3%. The haze value can be measured using a haze meter.

[0037] The size and density of the internal space affect the haze value. The size of the internal space (length M, width W: see Figs. 2 to 4) is, for example, preferably 10 μm or more and 500 μm or less in length M, and 1 μm or more and 100 μm or less in width W. From the viewpoint of the light extraction efficiency of the light extraction layer 2, the height H is preferably 1 μm or more and 100 μm or less. It is preferable that the multiple internal spaces are distributed discretely and uniformly, and for example, as shown in Fig. 2, it is preferable to arrange them periodically. The pitch Px is, for example, preferably 10 μm or more and 500 μm or less, and the pitch Py is, for example, preferably 10 μm or more and 500 μm or less. The interval E in Fig. 2 is the interval between the multiple internal spaces in the X direction. The interval D in Fig. 2 is the interval between the multiple internal spaces in the Y direction.

[0038] <Example of the structure of the adhesive layer 3> At least one of an acrylic, polyester, or other pressure sensitive adhesive and adhesive can be appropriately selected for the adhesive layer 3. The refractive index of the adhesive layer 3 is preferably similar to that of the light guide layer 1, and is preferably, for example, 1.45 or more and 1.60 or less.

[0039] The adhesive layer 3 is disposed between the light guide layer 1 and the light extraction layer 2. The ratio of the thickness of the adhesive layer 3 to the thickness t1 of the laminated film 10 can be 10% or more, and preferably 15% or more, and 20% or more. There is no particular upper limit, but it is, for example, 50% or less, 40% or less. By disposing such an adhesive layer 3 between the light guide layer 1 and the light extraction layer 2, the laminated film 10 can have suitable flexibility.

[0040] [Variations] Various modified examples will be described below. Note that the same names and reference numerals as those in the already described embodiments indicate the same or similar members or components, and detailed descriptions thereof will be omitted as appropriate.

[0041] <First Modification> 5 is a schematic cross-sectional view of a laminated film 10 according to a first modified example. The laminated film 10 according to the first modified example differs from the above-described embodiment in that light from a light source 50 can be further incident through an end 2a of the light extraction layer 2. In the first modified example, light from the light source 50 can be incident not only through the light incident surface 1b but also through the end 2a of the light extraction layer 2, thereby increasing the efficiency with which light from the light source 50 is incident on the laminated film 10.

[0042] As shown in FIG. 5, the light source 50 is disposed on the light incident surface 1b. Light from the light source 50 can enter the laminated film 10 through the light incident surface 1b and can also enter the laminated film 10 through the end 2a of the light extraction layer 2. The light source 50 is fixed to either the light guide layer 1 or the light extraction layer 2 by an adhesive member or the like. The end 2a of the light extraction layer 2 is the end located closest to the light source 50 among the multiple ends of the light extraction layer 2. In the example shown in FIG. 5, the light L1 from the light source 50 corresponds to the light entering the laminated film 10 through the light incident surface 1b. The light L2 from the light source 50 corresponds to the light entering the laminated film 10 through the end 2a of the light extraction layer 2.

[0043] The light extraction layer 2 may be disposed in contact with the light source 50. By disposing the light extraction layer 2 in contact with the light source 50, it is possible to reduce light loss caused by light from the light source 50 leaking out without entering the light extraction layer 2, and to increase the efficiency with which light from the light source 50 enters the light extraction layer 2.

[0044] <Second Modification> 6 is a schematic cross-sectional view of a laminated film 10 according to a second modification. The laminated film 10 according to the second modification is different from the above-described embodiment in that it has a pattern layer 4 disposed between the light guide layer 1 and the light extraction layer 2, and includes a first portion 401 having a lower refractive index than the light guide layer 1, and a second portion 402 having a higher refractive index than the first portion 401. The laminated film 10 according to the second modification can improve the uniformity of the luminance of the illumination light by the laminated film 10 according to the second modification by having the pattern layer 4. The pattern layer 4 may be configured so that the area of ​​the second portion 402 increases with increasing distance from the light incident surface.

[0045] The pattern layer 4 can be an optical coupling layer disclosed in WO 2022 / 025067. The entire disclosure of WO 2022 / 025067 is incorporated herein by reference. The first portion 401 may be a low refractive index layer or an air cavity. The second portion 402 may be made of a material having a refractive index approximately the same as that of the light guide layer 1 or the adhesive layer 3. When a low refractive index layer is used, the refractive index of the low refractive index layer is preferably, for example, 1.25 or less, more preferably 1.20 or less, and even more preferably 1.15 or less. The low refractive index layer is preferably a solid, and the refractive index is preferably, for example, 1.05 or more. The difference between the refractive index of the light guide layer 1 and the refractive index of the low refractive index layer is preferably 0.20 or more, more preferably 0.23 or more, and even more preferably 0.25 or more. The low refractive index layer having a refractive index of 1.25 or less can be formed, for example, using a porous material.

[0046] <Third Modification> 7 is a schematic cross-sectional view of a laminated film 10 according to a third modified example. The laminated film 10 according to the third modified example differs from the above-described embodiment in that, in a plan view, it has a tapered member 40 as a light incident member that is disposed on the light incident surface 1b and causes light from a light source 50 to enter the light guide layer. By having the tapered member 40, the laminated film 10 can increase the incidence efficiency of light L from the light source 50.

[0047] As shown in FIG. 7, the tapered member 40 has a bottom surface 41 for laminating on the upper surface 104 of the light guide layer 1, a light incident surface 42 for receiving the light L from the light source 50, and an inclined surface 43 for reflecting the light L incident on the tapered member 40 from the light source 50 and guiding it to the light guide layer 1 side. The inclined surface 43 can control the direction of the light incident on the inclined surface 43 at an angle less than the critical angle. The inclined surface 43 may be a flat surface or a curved surface. The curved surface of the inclined surface 43 may be a part of a spherical surface or a part of an aspherical surface. Examples of the aspherical surface include a parabolic surface. In the example shown in FIG. 7, the tapered member 40 has a tapered shape in which the thickness becomes thinner as it moves away from the light source 50.

[0048] The tapered member 40 can be made of a resin or glass material having a transmittance for the light L from the light source 50. The resin material can be an acrylic resin or the like. The transmittance here is preferably 60% or more.

[0049] The tapered member 40 is disposed on the light incident surface 1b. The tapered member 40 may be adhered to the light incident surface 1b with an adhesive or the like. From the viewpoint of increasing the incidence efficiency of the light L into the laminated film 10, it is preferable that the distance between the light extraction layer 2 and the tapered member 40 is short, and it is more preferable that the light extraction layer 2 and the tapered member 40 are in contact with each other.

[0050] When a plurality of light sources 50 are arranged in a row, the laminated film 10 may have a plurality of tapered members 40. Alternatively, the laminated film 10 may have one tapered member 40 having a length that allows light from each of the plurality of light sources 50 to be incident in the direction in which the plurality of light sources 50 are arranged.

[0051] The "optical incoupling element" disclosed in International Publication No. 2022 / 030544 can be used for the tapered member 40. The entire disclosure of International Publication No. 2022 / 030544 is incorporated herein by reference.

[0052] The tapered member 40 may be any member that controls the reflection direction of the light L incident at an angle less than the critical angle, and may be, for example, a diffraction grating or a layer having directionality including an optical cavity. The layer having directionality can be formed, for example, by laminating another film to a film on which an air cavity pattern is formed. The layer having directionality can be, for example, the "optical incoupling tape" disclosed in WO 2022 / 030543. The entire disclosure of WO 2022 / 030543 is incorporated herein by reference.

[0053] <Fourth Modification> 8 is a schematic cross-sectional view of a laminated film 10 according to a fourth modified example. The laminated film 10 according to the fourth modified example differs from the above-described embodiment in that, in a plan view, the laminated film 10 has a prism member 40a as a light incidence member that is disposed on the light incidence surface 1b and causes light from the light source 50 to enter the light guide layer. By having the prism member 40a, the laminated film 10 can increase the incidence efficiency of the light L from the light source 50.

[0054] 8, the prism member 40a has a bottom surface 41a for stacking on the upper surface 104 of the light guide layer 1, and a light incident surface 42a through which light L from the light source 50 is incident. The light source 50 and the prism member 40a may be integrally configured by arranging the light exit surface 50a of the light source 50 and the light incident surface 42a of the prism member 40a so as to be in contact with each other. By integrally configuring the light source 50 and the prism member 40a, it is possible to reduce interfacial reflection between the light source 50 and the prism member 40a and thereby reduce light loss, thereby increasing the light incidence efficiency.

[0055] The prism member 40a can be made of a resin or glass material having a transmittance for the light L from the light source 50. The resin material can be an acrylic resin or the like. The transmittance here is preferably 60% or more.

[0056] The prism member 40a is disposed on the light incident surface 1b. The prism member 40a may be adhered to the light incident surface 1b with an adhesive member or the like. From the viewpoint of increasing the incidence efficiency of the light L into the laminated film 10, the distance between the light extraction layer 2 and the prism member 40a is preferably short, and it is more preferable that the light extraction layer 2 and the prism member 40a are in contact with each other.

[0057] When a plurality of light sources 50 are arranged side by side, the laminated film 10 may have a plurality of prism members 40a, or may have one prism member 40a having a length that allows light from each of the plurality of light sources 50 to be incident in the direction in which the plurality of light sources 50 are arranged.

[0058] <Fifth Modification> 9 is a schematic cross-sectional view of a laminated film 10 according to a fifth modified example. The laminated film 10 according to the fifth modified example differs from the above-described embodiment in that the laminated film 10 according to the fifth modified example has a first light-transmitting member 40b disposed on the light incident surface 1b in a plan view and serving as a light incident member that causes light from the light source 50 to enter the light guide layer. By having the first light-transmitting member 40b, the laminated film 10 can increase the incidence efficiency of the light L from the light source 50.

[0059] The first light-transmitting member 40b is a rectangular parallelepiped member. The first light-transmitting member 40b can be disposed on the light incident surface 1b and between the end 2a of the light extraction layer 2 and the light exit surface 50a of the light source 50. After the light L from the light source 50 enters the inside of the first light-transmitting member 40b, a part of it is totally reflected at the upper surface of the first light-transmitting member 40b and enters the inside of the laminated film 10 through the end 2a of the light extraction layer 2, the end 3a of the adhesive layer 3, or the light incident surface 1b. The other part of the light L that entered the inside of the first light-transmitting member 40b enters the inside of the laminated film 10 through the end 2a, the end 3a, or the light incident surface 1b without being totally reflected at the upper surface of the first light-transmitting member 40b.

[0060] From the viewpoint of reducing the interfacial reflection and reducing the optical loss of the light incident on the laminated film 10 due to the interfacial reflection, the first light-transmitting member 40b is preferably arranged in contact with the end portion 2a and the light exit surface 50a. The first light-transmitting member 40b may be adhered to the light incident surface 1b with an adhesive member or the like.

[0061] In addition, the position of the end 2a and the position of the end 3a may be misaligned in the Y direction. In this case, if the first light-transmitting member 40b is arranged so as to contact either the end 2a or the end 3a, a gap is formed between the other of the end 2a or the end 3a and the first light-transmitting member 40b. The light L from the light source 50 is reflected at the interface at this gap, causing a loss of light incident on the laminated film 10. Therefore, it is preferable that the first light-transmitting member 40b is arranged while being pressed against at least one of the end 2a and the end 3a. By arranging the first light-transmitting member 40b while being pressed, the gap between the end 2a or the end 3a and the first light-transmitting member 40b can be reduced, and the efficiency of incidence of the light L from the light source 50 into the laminated film 10 can be increased.

[0062] The first light-transmitting member 40b can be made of a resin or glass material having a transmittance for the light L from the light source 50. The resin material can be an acrylic resin or the like. The transmittance here is preferably 60% or more.

[0063] When a plurality of light sources 50 are arranged side by side, the laminated film 10 may have a plurality of first light-transmitting members 40b, or may have one first light-transmitting member 40b having a length that allows light from each of the light sources 50 to be incident in the direction in which the plurality of light sources 50 are arranged.

[0064] 9, the laminated film 10 may further include a reflecting portion 60 disposed on the side of the first light-transmitting member 40b opposite to the side on which the light source 50 is located. For example, the reflecting portion 60 may be a reflecting sheet disposed on the surface of the first light-transmitting member 40b opposite to the side on which the light source 50 is located. The reflecting sheet is a sheet-like member including a reflecting surface, and is fixed by being attached to the surface of the first light-transmitting member 40b opposite to the side on which the light source 50 is located.

[0065] The reflecting portion 60 is not limited to a reflecting sheet. For example, the reflecting portion 60 may be a reflecting plate in which a reflecting film is formed on a plate-like member. The reflecting film may be made of a metal material such as aluminum. The reflecting portion 60 may be formed by applying a metal material by spraying or the like to a surface of the first light-transmitting member 40b opposite to the side where the light source 50 is located.

[0066] The laminated film 10 reflects the light L from the light source 50 incident on the first light-transmitting member 40b at the reflecting portion 60, thereby reducing the amount of the light L transmitted through the surface opposite to the side where the light source 50 is located and emitted to the outside of the first light-transmitting member 40b. This reduces light loss and increases the efficiency with which the light L from the light source 50 enters the laminated film 10. In addition, by using a reflecting sheet as the reflecting portion 60, the reflecting portion 60 can be easily disposed on the first light-transmitting member 40b.

[0067] <Sixth Modification> 10 is a schematic cross-sectional view of a laminated film 10 according to a sixth modified example. The laminated film 10 according to the sixth modified example differs from the above-described embodiment in that at least a part of the first surface 101, which is the surface of the light extraction layer 2 on the side opposite to the side where the light guide layer 1 is disposed, has a light incident surface 2b. By making at least a part of the first surface 101 the light incident surface 2b, it is possible to increase the efficiency with which light L from the light source 50 enters the laminated film 10.

[0068] 10, the laminated film 10 has a first light-transmitting member 40b. The first light-transmitting member 40b is disposed on the light incident surface 2b. The region of the light incident surface 2b corresponds to a region of the first surface 101 that faces the first light-transmitting member 40b. The first light-transmitting member 40b may be adhered to the light incident surface 2b with an adhesive member or the like.

[0069] The light source 50 is disposed such that the light emission surface 50a faces the first light-transmitting member 40b and also faces the end surface 103. In the example shown in FIG. 10, the end surface 103 is a surface constituted by the end surface 1a of the light guide layer 1, the end surface 2a of the light extraction layer 2, and the end surface 3a of the adhesive layer 3.

[0070] A part of the light L from the light source 50 enters the inside of the first light-transmitting member 40b, and the other part enters the laminated film 10 through the end face 103. A part of the light that entered the inside of the first light-transmitting member 40b is totally reflected at the upper surface of the first light-transmitting member 40b, and then enters the inside of the laminated film 10 through the light incident surface 1b. The other part of the light L that entered the inside of the first light-transmitting member 40b enters the inside of the laminated film 10 through the light incident surface 1b without being totally reflected at the upper surface of the first light-transmitting member 40b.

[0071] From the viewpoint of reducing interfacial reflection and reducing the optical loss of light incident on the laminated film 10 due to interfacial reflection, it is preferable that the light exit surface 50a be arranged in contact with the first light-transmitting member 40b and also in contact with the end surface 103.

[0072] In addition, the positions of the end 1a, the end 2a, and the end 3a may be shifted from each other in the Y direction. In this case, if the light source 50 is arranged so that the light exit surface 50a contacts one of the end 1a, the end 2a, or the end 3a, a gap is formed between the other end and the light exit surface 50a. The light L from the light source 50 is reflected at the interface at these gaps, causing a loss of light incident on the laminated film 10. Therefore, it is preferable that the light source 50 is arranged while pressing the light exit surface 50a against at least one of the end 1a, the end 2a, and the end 3a. By arranging the light source 50 while pressing the light exit surface 50a, the gap between each of the end 1a, the end 2a, and the end 3a and the light exit surface 50a can be reduced, and the incidence efficiency of the light L from the light source 50 into the laminated film 10 can be increased.

[0073] When a plurality of light sources 50 are arranged side by side, the laminated film 10 may have a plurality of first light-transmitting members 40b, or may have one first light-transmitting member 40b having a length that allows light from each of the light sources 50 to be incident in the direction in which the plurality of light sources 50 are arranged.

[0074] 10, the laminated film 10 may further include a reflecting portion 60 disposed on the side of the first light-transmitting member 40b opposite to the side on which the light source 50 is located. This reflecting portion 60 is substantially the same as that described in FIG. 9, and therefore a duplicated description will be omitted here.

[0075] <Seventh Modification> 11 is a schematic cross-sectional view of a laminated film 10 according to a seventh modification. In the seventh modification, the second light-transmitting member 40c as a light incident member is disposed so that a part of the second light-transmitting member 40c faces the light incident surface 2b and another part faces the end surface 103, which is different from the sixth modification. A part of the second light-transmitting member 40c faces the light incident surface 2b and another part faces the end surface 103. By including the second light-transmitting member 40c, it is possible to increase the efficiency with which light L from the light source 50 is incident on the laminated film 10.

[0076] In the example shown in FIG. 11, the second light-transmitting member 40c has a first opposing surface 41c and a second opposing surface 42c. The first opposing surface 41c is a surface facing the light incident surface 2b. The second opposing surface 42c is a surface facing the end surface 103. In the example shown in FIG. 11, the end surface 103 is a surface constituted by the end portion 1a of the light guide layer 1, the end portion 2a of the light extraction layer 2, and the end portion 3a of the adhesive layer 3. The region of the light incident surface 2b corresponds to the region of the first surface 101 facing the first opposing surface 41c. The second light-transmitting member 40c may be adhered to at least one of the light incident surface 2b and the end surface 103 with an adhesive member or the like.

[0077] The light source 50 is disposed so that the light exit surface 50a faces the second light-transmitting member 40c. Light L from the light source 50 enters the inside of the second light-transmitting member 40c. A part of the light that enters the inside of the second light-transmitting member 40c is totally reflected by the upper surface of the second light-transmitting member 40c, and then enters the inside of the laminated film 10 through the light incident surface 2b or the end surface 103. Another part of the light that enters the inside of the second light-transmitting member 40c enters the inside of the laminated film 10 through the light incident surface 2b or the end surface 103 without being totally reflected by the upper surface of the second light-transmitting member 40c.

[0078] From the viewpoint of reducing interfacial reflection and reducing the optical loss of light incident on the laminated film 10 due to interfacial reflection, it is preferable that the light exit surface 50a is arranged in contact with the second translucent member 40c, the first opposing surface 41c is arranged in contact with the light incident surface 2b, and the second opposing surface 42c is arranged in contact with the end surface 103.

[0079] In addition, the positions of the end 1a, the end 2a, and the end 3a may be shifted from each other in the Y direction. In this case, if the second light-transmitting member 40c is arranged so as to contact one of the end 1a, the end 2a, and the end 3a, a gap is formed between the other end and the second light-transmitting member 40c. The light L from the light source 50 is reflected at the interface at these gaps, causing a loss of light incident on the laminated film 10. Therefore, it is preferable that the second light-transmitting member 40c is arranged while being pressed against at least one of the end 1a, the end 2a, and the end 3a. By arranging the second light-transmitting member 40c while being pressed, the gap between each of the end 1a, the end 2a, and the end 3a and the second light-transmitting member 40c can be reduced, and the efficiency of incidence of the light L from the light source 50 into the laminated film 10 can be increased.

[0080] When a plurality of light sources 50 are arranged in a row, the laminated film 10 may have a plurality of second light-transmitting members 40c, or may have one second light-transmitting member 40c having a length that allows light from each of the light sources 50 to be incident in the direction in which the plurality of light sources 50 are arranged.

[0081] 11, the laminated film 10 may further include a reflecting portion 60 disposed on the side of the second light-transmitting member 40c opposite to the side on which the light source 50 is located. This reflecting portion 60 is substantially the same as that described in FIG. 9, except that it is disposed on the second light-transmitting member 40c, and therefore a duplicated description will be omitted here.

[0082] <Eighth Modification> 12 is a schematic cross-sectional view of a laminated film 10 according to an eighth modification. The laminated film 10 according to the eighth modification is different from the sixth modification in that at least a part of the second surface 102, which is the surface of the light guide layer 1 on the side opposite to the side where the light extraction layer 2 is disposed, is made the light incident surface 2b. The effects of the eighth modification are similar to those of the sixth modification.

[0083] <Ninth Variation> 13 is a schematic cross-sectional view of a laminated film 10 according to a ninth modification. The laminated film 10 according to the ninth modification is different from the seventh modification in that at least a part of the second surface 102, which is the surface of the light guide layer 1 on the side opposite to the side where the light extraction layer 2 is disposed, is made the light incident surface 2b. The effects of the ninth modification are similar to those of the seventh modification.

[0084] [Examples and Comparative Examples] Examples and comparative examples are described below. However, the present invention is not limited to these examples. In the following description, in order to make the description easier to understand, the same reference numerals as those shown in FIG. 1 may be used for the substantially same configurations as those of the laminated film 10 shown in FIG. 1 in comparative examples 1 to 3 for convenience.

[0085] <Evaluation method> (Evaluation of the degree of luminescence) Light was irradiated from a light source 50 into the laminated film according to the examples and comparative examples, and the light was extracted from the light extraction layer side. The luminance of the extracted light was evaluated visually. The following shows the definitions of the evaluation indices "A" to [D] for the degree of luminescence. A: Very good (very bright). B: Good (high brightness). C: Fairly good (brightness is somewhat high). D: Poor (low brightness).

[0086] (Flexibility evaluation) The flexibility of the laminated films according to the examples and comparative examples was evaluated by a sensory test. The flexibility evaluation indices "A" to "D" are defined below. A: Very good (soft enough to be rolled up when long). B: Good (inferior to A, but soft enough to be wound into a roll when long). C: Fairly good (inferior to B, but soft enough to be wound into a roll when long). D: Poor (difficult to wind up in rolls when long)

[0087] (Evaluation of light incidence stability) The laminated films according to the examples and comparative examples were subjected to a sensory evaluation of the light incidence stability. The evaluation indices for the light incidence stability, "A" to "C", are defined below. A: Stable light input is possible easily B: Stable light input is possible C: Stable light input is difficult

[0088] Example 1 The conditions for the laminated film according to Example 1 are shown below. Light guide layer 1: Made of acrylic resin and had a thickness of 130 μm. Adhesive layer 3: Made of resin (CS9864) and had a thickness of 100 μm. · Base film of light extraction layer 2: Made of acrylic resin and had a thickness of 30 μm. Adhesive for light extraction layer 2: The material was polyester resin, and the thickness was 7 μm. The uneven film of the light extraction layer 2: The material was acrylic resin, and the thickness was 128 μm. The overall thickness of the laminated film 10 was 395 μm. The length from the end 1a of the light guide layer 1 to the end 2a of the light extraction layer 2 at the light incident surface 1b was set to 50 mm. The light from the light source 50 was incident on the inside of the laminated film through the light incident surface 1 b and the end surface 103 .

[0089] Example 2 The same as in Example 1 was performed except that a tapered member 40 was placed on the light incident surface 1b (third variant), and light from the light source 50 was made to enter the laminated film through both the light incident surface 1b and the end surface 103 via the tapered member 40.

[0090] Example 3 The same as in Example 1 was used except that a tapered member 40 was placed on the light incident surface 1b (third modified example) and light from the light source 50 was made to enter the laminated film via the tapered member 40 only through the light incident surface 1b.

[0091] Example 4 The thickness of the light guide layer 1 was set to 170 μm. The thickness of the light extraction layer 2 was set to 725 μm. The total thickness of the laminated film was 995 μm. Other than the above, the embodiment was the same as the first embodiment.

[0092] Example 5 The thickness of the light guide layer 1 was set to 170 μm. The thickness of the light extraction layer 2 was set to 725 μm. The total thickness of the laminated film was 995 μm. Other than the above, the embodiment was the same as Example 2.

[0093] Example 6 The thickness of the light guide layer 1 was set to 170 μm. The thickness of the light extraction layer 2 was set to 725 μm. The total thickness of the laminated film was 995 μm. Other than the above, the same as in Example 3.

[0094] Example 7 The thickness of the light guide layer 1 was set to 30 μm. The total thickness of the laminated film was 295 μm. Other than the above, the embodiment was the same as the first embodiment.

[0095] Example 8 The thickness of the light guide layer 1 was set to 30 μm. The total thickness of the laminated film was 295 μm. Other than the above, the embodiment was the same as Example 2.

[0096] Example 9 The embodiment was the same as the first embodiment, except that a prism member 40a (fourth modification) was used as the light entrance member.

[0097] Example 10 The embodiment was the same as the first embodiment, except that a first light-transmitting member 40b (fifth modification) was used as the light entrance member.

[0098] Example 11 Except for the fact that there was no non-overlapping region and that a first light-transmitting member 40b (sixth modified example) was used as the light entrance member, the third embodiment was the same as the first embodiment. Here, the non-overlapping region refers to a region of the light guide layer where the light extraction layer and the light guide layer do not overlap in a plan view.

[0099] Example 12 The embodiment was the same as the first embodiment, except that there was no non-overlapping region and a second light-transmitting member 40c (seventh modification) was used as the light entrance member.

[0100] Comparative Example 1 The same procedure as in Example 1 was followed except that the light from the light source 50 was incident on the laminated film through the end surface 103 .

[0101] Comparative Example 2 The same procedure as in Example 1 was followed except that the non-overlapping region was set to “none” and the light from the light source 50 was incident on the laminated film through the end surface 103 .

[0102] Comparative Example 3 The thickness of the light guide layer was 1000 μm, the thickness of the adhesive layer was 50 μm, the thickness of the light extraction layer was 165 μm, the thickness of the entire laminated film was 1215 μm, and the light from the light source 50 was incident on the laminated film through the end surface 103, all other points being the same as in Example 1.

[0103] Table 1 shows a list of the conditions and evaluation results in each of Examples 1 to 12 and Comparative Examples 1 to 3. [Table 1]

[0104] As shown in Table 1, in Examples 1 to 12, the "luminescence degree" was "A" to "C", and all of them obtained good results. In addition, in Examples 1 to 12, the "flexibility" was either "A" to "C", and a degree of flexibility that allows winding into a roll was obtained. Furthermore, in Examples 1 to 12, the "light incidence stability" was "A" or "B", and good results were obtained. The luminescence degree was the best in Example 12, followed by Examples 10 and 11. The luminescence degree was higher when the laminated film 10 had the reflective portion 60, but sufficient luminescence was obtained even when the laminated film 10 did not have the reflective portion 60.

[0105] In Comparative Examples 1 and 2, the "light incidence stability" was rated as "C", and good results were not obtained. In Comparative Example 3, the "light incidence stability" was rated as "A", but the "flexibility" was rated as "D", which meant that the film could not be wound into a roll.

[0106] As described above, it was found that in Examples 1 to 12, laminate films were obtained which were good in both "luminescence degree" and "light incidence stability" and had "flexibility" that allowed them to be wound into a roll.

[0107] [Other preferred variations] The laminate film 10 according to the embodiment may have a low refractive index layer disposed on one side of the laminate film 10 and having a refractive index lower than that of the light guide layer 1. The low refractive index layer preferably has a refractive index of 1.30 or less. From the viewpoint of reducing the presence of the laminate film 10 when placed on an adherend, the total thickness from the surface of the laminate film 10 on the side opposite to the side on which the low refractive index layer is disposed to the surface of the laminate film 10 on the side on which the low refractive index layer is disposed is preferably 1500 μm or less.

[0108] The adherend on which the laminated film 10 is placed is not limited to glass, but may be an electronic substrate such as a liquid crystal cell, or a non-light-transmitting member such as a ceiling, a wall, or a floor. The light extraction layer 2 is not limited to extracting light L to the side opposite to the side on which the adherend is located, but may extract light L to the side on which the adherend is located. In this case, if the adherend has high light transmittance, the extracted light L may pass through the adherend, and if the adherend has low light transmittance, the adherend may reflect the light.

[0109] A substrate film may be further disposed on the side of the light extraction layer 2 opposite to the side where the light guide layer 1 is located. This substrate film may be a hard coat layer or an anti-reflection layer. Furthermore, a low refractive index layer may be disposed between the light extraction layer 2 and the substrate film, or a low refractive index layer may be disposed between the light guide layer and the substrate film. From the viewpoint of reducing the presence of the laminated film 10 when placed on an adherend, even when these members are present, the thickness of the light guide member is preferably 1000 μm or less, more preferably 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, 400 μm or less, or 300 μm or less.

[0110] The light guide layer 1 and the light extraction layer 2 are not limited to being separate films, and may be integrated with each other. For example, the light guide layer 1 having patterned recesses can function as both the light guide layer 1 and the light extraction layer 2.

[0111] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0112] The ordinal numbers, quantities, and other numbers used in the description of the embodiments are all provided as examples to specifically explain the technology of the present invention, and the present invention is not limited to the exemplified numbers. Furthermore, the connection relationships between the components are provided as examples to specifically explain the technology of the present invention, and do not limit the connection relationships that realize the functions of the present invention.

[0113] The laminated film according to the embodiment can increase the incidence efficiency of light from a light source, and therefore, when combined with a light source and placed on architectural components such as glass, windows, walls, floors, and ceilings, it can brightly illuminate the interior or exterior space of a building. When placed on a partition, it can be used to partition an interior space or to conceal a desired space. When placed on a glass substrate of a display device such as a liquid crystal panel or an organic EL (Electro Luminescence) display panel, it can brighten the backlight illumination of the display device. The laminated film 10 can also be used as a flexible lighting film without being placed on an adherend. Furthermore, the laminated film according to the embodiment can provide new uses other than those mentioned above.

[0114] A surface illumination device can also be configured by a laminate film according to the embodiment and a light source arranged so that light is incident on the light incident surface of the laminate film directly or via a light incident member.

[0115] For example, aspects of the present invention are as follows. <1> The laminated film has a plurality of layers stacked together, the laminated film having an end face along the stacking direction, a light incident surface that intersects with the end face and allows light from a light source to be incident thereon, a light guide layer that guides the light incident through the light incident surface, and a light extraction layer including a light extraction portion that can extract light guided by the light guide layer, wherein the thickness between a first surface, which is the surface of the light extraction layer on the side opposite to the side on which the light guide layer is arranged, and a second surface, which is the surface of the light guide layer on the side opposite to the side on which the light extraction layer is arranged, is 1000 μm or less. <2> a light incidence member disposed on the light incidence surface and allowing light from the light source to be incident thereon; <1> 2. The laminated film according to claim 1 . <3> the light incidence member is disposed so that a portion of the light incidence member faces the light incidence surface and another portion of the light incidence member faces the end surface; <2> 2. The laminated film according to claim 1 . <4> The light receiving member further includes a reflecting portion disposed on a side opposite to a side on which the light source is located. <3> 2. The laminated film according to claim 1 . <5> The reflecting portion is a reflecting sheet disposed on a surface of the light incident member opposite to a surface on which the light source is located. <4> 2. The laminated film according to claim 1 . <6> The thickness of the light guide layer is 30 μm or more. <1> or the above <2> 2. The laminated film according to claim 1 . <7> a pattern layer disposed between the light guiding layer and the light extraction layer, the pattern layer including a first portion having a lower refractive index than the light guiding layer and a second portion having a higher refractive index than the first portion; <1> From the above <6> 10. The laminated film according to claim 9, wherein the first and second layers are laminated together. <8> an end of the light extraction layer is located inside the light guide layer with respect to an end of the light guide layer in a plan view, and the light incident surface is located in a region of the light guide layer where the light extraction layer and the light guide layer do not overlap with each other in a plan view; <1> From the above <7> 10. The laminated film according to claim 9, wherein the first and second layers are laminated together. <9> The light extraction layer is disposed on a side of the light guide layer where the light source is disposed. <8> 2. The laminated film according to claim 1 . <10> The light from the light source can be further incident through the edge of the light extraction layer. <8> or the above <9> 2. The laminated film according to claim 1 . <11> The light extraction layer is disposed in contact with the light source. <10> 2. The laminated film according to claim 1 . <12> The film is formed in a long shape so that it can be wound up. <1> From the above <11> 10. The laminated film according to claim 9, wherein the first and second layers are laminated together. [Explanation of symbols]

[0116] 1 Light guiding layer 1a end 1b, 2b Light incidence surface 101 Page 1 102 Side 2 103 End face 104 Top surface 2 Light extraction layer 2a end 21 Light extraction part 3 Adhesive layer 3a end 4 Pattern Layer 401 Part 1 402 Part 2 10 Laminated film 40 Tapered member (an example of a light input member) 41 Bottom 42 Light entrance surface 43 Slope 40a Prism member (an example of a light input member) 41a Bottom 42a Light entrance surface 40b: First light-transmitting member (an example of a light incident member) 40c: Second light-transmitting member (an example of a light incidence member) 41c 1st facing surface 42c Second opposing surface 50 light source 50a Light exit surface 60 Reflector L, L1, L2 light t1 Thickness of laminated film t2 Thickness of the light guide layer Distance between multiple internal spaces in the DY direction Spacing between multiple internal spaces in the EX direction M Length Px Pitch of multiple internal spaces in the X direction Py Pitch of multiple internal spaces in the Y direction H Height W width θa, θb angle

Claims

1. A laminated film in which a plurality of layers are laminated, An end surface along the lamination direction; a light incident surface that intersects with the end surface and through which light from a light source is incident; a light guide layer that guides light incident through the light incident surface; a light extraction layer including a light extraction portion capable of extracting light guided by the light guide layer; A laminated film, wherein the thickness between a first surface, which is the surface of the light extraction layer on the side opposite to the side on which the light guide layer is arranged, and a second surface, which is the surface of the light guide layer on the side opposite to the side on which the light extraction layer is arranged, is 1000 μm or less.

2. The laminated film according to claim 1 , further comprising a light incidence member disposed on the light incidence surface to allow the light from the light source to be incident thereon.

3. The laminated film according to claim 2 , wherein the light incidence member is disposed such that a portion of the light incidence member faces the light incidence surface and another portion faces the end surface.

4. The laminated film according to claim 3 , further comprising a reflecting portion disposed on the side of the light incidence member opposite to the side on which the light source is located.

5. The laminated film according to claim 4 , wherein the reflecting portion is a reflecting sheet disposed on a surface of the light incident member opposite to a side on which the light source is located.

6. The laminated film according to claim 1 or 2, wherein the light guide layer has a thickness of 30 μm or more.

7. 3. The laminated film according to claim 1, further comprising a pattern layer disposed between the light guide layer and the light extraction layer, the pattern layer including a first portion having a lower refractive index than the light guide layer and a second portion having a higher refractive index than the first portion.

8. an end of the light extraction layer is located on the inner side of the light guide layer with respect to an end of the light guide layer in a plan view; The laminated film according to claim 1 , wherein the light incident surface is located in a region of the light guide layer where the light extraction layer and the light guide layer do not overlap in a plan view.

9. The laminated film according to claim 8 , wherein the light extraction layer is disposed on a side of the light guide layer on which the light source is disposed.

10. The laminated film of claim 8 , wherein light from the light source can further enter through an edge of the light extraction layer.

11. The laminate film of claim 10 , wherein the light extraction layer is disposed in contact with the light source.

12. The laminate film according to claim 1 or 2, which is formed into a long shape so as to be windable.

Images