Laminate film and roll

Abstract

To provide a laminate film having high design effect, and a roll.SOLUTION: The laminate film has: a light guide member for guiding light incident from a light source; and a low refractive index layer arranged on one side of the light guide member and having a refractive index of 1.30 or lower. The light guide member includes a light extraction part capable of extracting the light guided by the light guide member. A thickness of the light guide member is 1,000 μm or smaller. A whole thickness from a first face as a surface of the light guide member on the opposite side to the side where the low refractive index is arranged to a second face as a surface of the low refractive index layer on the opposite side to the light guide member is 1,500 μm or smaller.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a laminated film and a roll. [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 having a light guide plate and a first protective plate that is entirely adhered to one surface of the light guide plate using a low refractive index resin that has a lower refractive index than the light guide plate. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2008-299117 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration of Patent Document 1, the thickness of the configuration consisting of the light guide plate and the first protective plate may reduce the design quality of the laminated film.

[0006] An object of the present invention is to provide a laminated film and roll having excellent designability. [Means for solving the problem]

[0007] The laminated film according to one embodiment of the present invention comprises a light-guiding member that guides light incident from a light source, and a low refractive index layer that is arranged on one side of the light-guiding member and has a refractive index of 1.30 or less, wherein the light-guiding member includes a light extraction portion that is capable of extracting light guided by the light-guiding member, the light-guiding member has a thickness of 1000 μm or less, and an overall thickness from a first surface, which is the surface of the light-guiding member on the side opposite to the side on which the low refractive index layer is arranged, to a second surface, which is the surface of the low refractive index layer on the side opposite to the light-guiding member, is 1500 μm or less. Effect of the Invention

[0008] According to the present invention, it is possible to provide a laminate film and roll having a highly attractive design. [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] 3 is a schematic cross-sectional view of a light extraction portion according to the first embodiment. FIG. [Figure 6] 3 is a schematic plan view of a light extraction unit according to the first embodiment. FIG. 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, plan view means viewing an object from the Z direction. Also, the +Z direction is called "up". The adherend on which the laminated film according to the embodiment is placed is located in the -Z direction as viewed from the laminated film. However, these directional expressions do not limit the directions of the embodiment. Also, 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 an example of a laminated film 10 according to the first embodiment. In the example shown in FIG. 1, the laminated film 10 has a light guide member 1 that guides light L incident from a light source 50, and a low refractive index layer 2 that is disposed on one side of the light guide member 1 and has a refractive index of 1.30 or less. The low refractive index layer 2 can be disposed on one side of the light guide member 1 via a third adhesive layer 9. The light guide member 1 includes a light extraction portion 31 that can extract the light L guided by the light guide member 1. The thickness t1 of the light guide member 1 is 1000 μm or less. The thickness t1 of the light guide member 1 is 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. The lower limit is not particularly limited, but is 100 μm or more, 200 μm or more. The total thickness t2 from the first surface 11, which is the surface of the light guide member 1 on the side opposite to the side where the low refractive index layer 2 is disposed, to the second surface 12, which is the surface of the low refractive index layer 2 on the side opposite to the light guide member 1, is 1500 μm or less. The total thickness t2 is preferably 1000 μm or less, 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 preferably 100 μm or more, or 200 μm or more.

[0015] The laminated film 10 can guide the light L incident from the light source 50 by the light guide member 1, and can extract the light L from inside the light guide member 1 to the outside by the light extraction portion 31. The laminated film 10 can illuminate a space in which the laminated film 10 is placed by the light L extracted from the light guide member 1. The light source 50 is, for example, an LED (Light Emitting Diode) light source.

[0016] By setting the thickness t1 of the light guide member 1 to 1000 μm or less and the overall thickness t2 to 1500 μm or less, the presence of the laminate film 10 can be reduced and the laminate film 10 can be made inconspicuous. In this embodiment, by reducing the presence of the laminate film 10, a laminate film 10 with high designability can be provided. Furthermore, the laminate film 10 can improve the designability of the adherend 20 on which the laminate film 10 is arranged.

[0017] Moreover, by setting the total thickness t2 of the laminate film 10 to 1500 μm or less, the laminate film 10 can be made flexible. By making the laminate film 10 flexible, it is possible to reduce poor placement, such as wrinkles occurring when the laminate film 10 is placed on the adherend 20, or air getting between the laminate film 10 and the adherend 20. Unlike the conventional light guide plate that is a plate-shaped member, the laminate film 10 can be handled in a roll with the light guide member integrated. In other words, in this embodiment, a roll of the laminate film 10 with high designability can be provided.

[0018] In addition, when the light L guided through the laminated film 10 reaches the adherend 20 on which the laminated film 10 is disposed, the reaching light L may be scattered by the adherend 20, thereby attenuating the luminance of the illumination light, or the reaching light may be absorbed by the adherend 20, thereby changing the hue of the illumination light. For example, if the adherend 20 is float glass, the float glass absorbs light having a wavelength corresponding to red among the light L that reaches the float glass, and the illumination light is visually recognized as being colored blue. By having the low refractive index layer 2, the laminated film 10 can totally reflect the light L guided by the light guide member 1 at the low refractive index layer 2, thereby reducing the light L from reaching the adherend 20. This can reduce the luminance attenuation and hue change of the illumination light caused by the laminated film 10.

[0019] The laminated film 10 can be disposed on an adherend 20. Examples of the adherend 20 include glass, windows, walls, floors, ceilings, etc. For example, the laminated film 10 is disposed by being attached to the surface of the adherend 20.

[0020] The laminate film 10 can be made of a resin. The laminate film 10 is highly flexible due to being made of a resin, and can be handled in various forms. For example, the laminate film 10 before being placed on the adherend 20 has a release liner provided on the first adhesive layer 7, and can be handled in the form of a long roll, making it easy to handle. However, the laminate film 10 does not necessarily have to be made of a resin, and at least a part of it may be made of glass or the like.

[0021] The laminated film 10 can have a first adhesive layer 7 arranged on the side of the low refractive index layer 2 opposite to the light guiding member 1. By having the first adhesive layer 7, the laminated film 10 can fix the light guiding member 1, the third adhesive layer 9 and the low refractive index layer 2 onto the adherend 20.

[0022] The light guiding member 1 can have a light extraction layer 3 including a light extraction portion 31, and a transmissive layer 4 that transmits light L incident from a light source 50. By having the light extraction layer 3 and the transmissive layer 4, the light guiding member 1 can guide the light L incident from the light source 50 and extract the light L from the inside of the light guiding member 1 to the outside.

[0023] In the laminate film 10, the thickness t3 of the transmissive layer 4 can be set to 30 μm or more. By setting the thickness t3 of the transmissive layer 4 to 30 μm or more, the incidence efficiency of the light L from the light source 50 entering the laminate film 10 can be increased.

[0024] The light extraction portions 31 may be a plurality of internal spaces provided in the light extraction layer 3. When the light extraction portions 31 are a plurality of internal spaces provided in the light extraction layer 3, the laminate film 10 can extract the highly directional light L from the inside of the light-guiding member 1 to the outside.

[0025] The laminated film 10 may have a second viscoadhesive layer 8 disposed between the transmissive layer 4 and the light extraction layer 3. The ratio of the thickness of the second viscoadhesive layer 8 to the thickness of the light guide member 1 may be 10% or more, preferably 15% or more and 20%, and the upper limit is not particularly limited, but is, for example, 50% or less, 40% or less. By disposing such a second viscoadhesive layer 8 between the transmissive layer 4 and the light extraction layer 3, the laminated film 10 can have suitable flexibility.

[0026] In plan view, the end 3a of the light extraction layer 3 may be located inside the end 4a of the transmission layer 4. For example, the distance between the end 3a of the light extraction layer 3 and the end 4a of the transmission layer 4 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. In plan view, the end 3a of the light extraction layer 3 is located inside the end 4a of the transmission layer 4, so that a member for allowing the light L from the light source 50 to enter the laminated film 10 can be arranged in the region 4b of the transmission layer 4 where the light extraction layer 3 and the transmission layer 4 do not overlap, and the incidence efficiency of the light L from the light source 50 to the laminated film 10 can be increased. The region 4b is defined by the end 3a of the light extraction layer 3 and the end 4a of the transmission layer 4.

[0027] The laminated film 10 can have a light entrance member 40 that is disposed in a region 4b of the transmissive layer 4 where the light extraction layer 3 and the transmissive layer 4 do not overlap in a planar view, and that allows light L from the light source 50 to enter the laminated film 10. With this configuration, the laminated film 10 allows light L to easily enter the laminated film 10 from the light source 50.

[0028] The light extraction layer 3 can include a light extraction portion forming layer 30 in which the light extraction portions 31 are formed, a substrate 5, and a fourth adhesive layer 6 disposed between the light extraction portion forming layer 30 and the substrate 5 and adhesively bonding the light extraction portion forming layer 30 and the substrate 5. The laminated film 10 can have a third adhesive layer 9 disposed between the transmissive layer 4 and the low refractive index layer 2 and adhesively bonding the transmissive layer 4 and the low refractive index layer 2.

[0029] <Configuration example of low refractive index layer 2> The refractive index of the low refractive index layer 2 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 2 is preferably a solid, and the refractive index is, for example, 1.05 or more. The difference between the refractive index of the transparent layer 4 and the refractive index of the low refractive index layer 2 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 2 having a refractive index of 1.25 or less can be formed, for example, using a porous material. The thickness of the low refractive index layer 2 is, for example, 0.3 μm or more and 5.0 μm or less. The low refractive index layer 2 is used by being coated on a substrate film (not shown), such as an acrylic film. The low refractive index layer 2 and the substrate film (not shown) are arranged in the order of the first adhesive layer 7, the low refractive index layer 2, the substrate film (not shown), and the third adhesive layer 9. The thickness of the substrate film (not shown) is, for example, 5 μm or more and 100 μm or less, preferably 50 μm or less.

[0030] When the low refractive index layer 2 is a porous material having voids therein, the porosity is preferably 35% by volume or more, more preferably 38% by volume or more, and particularly preferably 40% by volume or more. Within this range, a low refractive index layer with a particularly low refractive index can be formed. The upper limit of the porosity of the low refractive index layer is, for example, 90% by volume or less, preferably 75% by volume or less. Within this range, a low refractive index layer with excellent strength can be formed. The porosity here is a value calculated from the refractive index measured by an ellipsometer using the Lorentz-Lorenz's formula.

[0031] For the low refractive index layer 2, for example, a low refractive index layer having voids disclosed in International Publication No. 2019 / 146628 can be used. The entire disclosure of International Publication No. 2019 / 146628 is incorporated herein by reference. Specifically, the low refractive index layer having voids includes substantially spherical particles such as silica particles, silica particles having micropores, hollow silica nanoparticles, fibrous particles such as cellulose nanofibers, alumina nanofibers, and silica nanofibers, and flat particles such as nanoclay composed of bentonite. In one embodiment, the low refractive index layer having voids is a porous body formed by direct chemical bonding of particles (e.g., microporous particles). In addition, at least a portion of the particles constituting the low refractive index layer having voids may be bonded to each other via a small amount (e.g., equal to or less than the mass of the particles) of a binder component. The porosity and refractive index of the low refractive index layer can be adjusted by the particle size, particle size distribution, etc. of the particles constituting the low refractive index layer.

[0032] Methods for obtaining a low refractive index layer having voids include, for example, methods described in JP 2010-189212 A, JP 2008-040171 A, JP 2006-011175 A, WO 2004 / 113966 A, and references thereto. The disclosures of JP 2010-189212 A, JP 2008-040171 A, JP 2006-011175 A, and WO 2004 / 113966 A are all incorporated herein by reference.

[0033] A porous silica body can be suitably used as a low refractive index layer having voids. The porous silica body can be manufactured, for example, by the following methods. Silicon compound: A method of hydrolyzing and polycondensing at least one of hydrolyzable silanes and silsesquioxane, and at least one of their partial hydrolyzates and dehydration condensates, a method of using at least one of porous particles and hollow fine particles, a method of generating an aerogel layer by utilizing the springback phenomenon, a method of using a crushed gel in which a gel-like silicon compound obtained by a sol-gel method is crushed and the obtained crushed body, that is, microporous particles, are chemically bonded to each other by a catalyst or the like, and the like.

[0034] The low refractive index layer 2 is not limited to a porous silica material. The manufacturing method of the low refractive index layer 2 is not limited to the exemplified manufacturing methods either, and any manufacturing method may be used. In addition, the porous layer is not limited to a porous silica material, and the manufacturing method is not limited to the exemplified manufacturing methods either, and any manufacturing method may be used.

[0035] Silsesquioxane is (RSiO 1.5 SiO 2 However, since it has a network structure cross-linked by siloxane bonds in common with silica, here, a porous material containing silsesquioxane as a basic structural unit is also referred to as a silica porous material or a silica-based porous material.

[0036] The silica porous body can be composed of microporous particles of gel-like silicon compound bonded together. The microporous particles of gel-like silicon compound include pulverized gel-like silicon compound. The silica porous body can be formed, for example, by applying a coating liquid containing pulverized gel-like silicon compound to a substrate. The pulverized gel-like silicon compound can be chemically bonded (for example, siloxane bonded) by, for example, the action of a catalyst, light irradiation, heating, etc.

[0037] <Configuration example of light extraction layer 3> An example of the configuration of the light extraction layer 3 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 3. Fig. 3 is a cross-sectional view that shows a schematic view of the light extraction layer 3. Fig. 4 is a cross-sectional view that shows a schematic view of the light extraction portion 31.

[0038] The light extraction section 31 included in the light extraction layer 3 may be a plurality of internal spaces provided in the light extraction layer 3. 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 member 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 light emission direction can be changed by changing the cross-sectional shape of the internal space (for example, the direction of the apex angle of the triangle).

[0039] The laminated film 10 can extract the light L guided by the light guide member 1 by the light extraction portion 31 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 portion 31, the light distribution, emission efficiency, and luminance distribution of the light L emitted from the laminated film 10 can be controlled. The light extraction portion 31 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 portion forming layer 30 instead of air.

[0040] In the light guide member 1, a plurality of internal spaces that are light extraction sections 31 are arranged regularly or randomly along the main surface, that is, a plane that is approximately 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 section forming layer 30. For the light extraction section forming layer 30 that contains the light extraction section 31 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.

[0041] The light extraction layer 3 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).

[0042] 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.

[0043] From the viewpoint of obtaining a good visible light transmittance and haze value, the ratio (occupancy rate) of the area of ​​the plurality of internal spaces, which are the light extraction portion 31, to the area of ​​the light extraction portion forming layer 30 in a plan view is preferably 30% or less. 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 a 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.

[0044] The above-mentioned features of the light extraction portion 31 are not limited to the multiple internal spaces formed in the light extraction portion forming layer 30 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.

[0045] The light extraction portion 31 is not limited to a plurality of internal spaces, and may be a plurality of prisms arranged in the light extraction portion forming layer 30. The light extraction portion forming layer 30 may be a prism sheet including a plurality of prisms therein. A plurality of convex portions (prism portions) may be formed directly on the surface of the light extraction portion forming layer 30. The refractive index of the light extraction portion forming layer 30 is preferably approximately equal to the refractive indexes of the base material 5 and the fourth adhesive layer 6, and the difference (absolute value) between the refractive indices is preferably 0.15 or less, and more preferably 0.1 or less.

[0046] A light distribution control structure in which the light extraction unit 31 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 multiple internal spaces of the light extraction unit 31. 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.

[0047] 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 3, 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.

[0048] <Example of the configuration of transparent layer 4> 1, the transmissive layer 4 can be formed from a film having flat surfaces on both sides. A material having a low light absorption coefficient is preferable for the transmissive layer 4. For example, the transmissive layer 4 can be made of 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), or a polycarbonate film.

[0049] From the viewpoint of the incidence efficiency of the light from the light source 50 entering the laminated film 10, the thickness t3 of the transmission layer 4 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 t3 of the transmission layer 4 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. The refractive index of the transmission layer 4 is preferably, for example, 1.45 or more and 1.60 or less. It is preferable that the same film as the transmission layer 4 is used for the substrate film on which the low refractive index layer 2 is coated, the light extraction layer 3, and the substrate film laminated with the light extraction layer 3.

[0050] <Configuration Examples of the First to Fourth Pressure-Acting Adhesive Layers> At least one of an acrylic, polyester, or other pressure-sensitive adhesive and adhesive can be appropriately selected for each of the first tacky-adhesive layer 7, the second tacky-adhesive layer 8, the third tacky-adhesive layer 9, and the fourth tacky-adhesive layer 6. The refractive index of each of the first tacky-adhesive layer 7, the second tacky-adhesive layer 8, the third tacky-adhesive layer 9, and the fourth tacky-adhesive layer 6 is preferably similar to that of the transparent layer 4, and is preferably, for example, 1.45 or more and 1.60 or less.

[0051] <Configuration Example of Light Incident Member 40> The light incidence member 40 has a bottom surface 41 for laminating on a surface such as the upper surface of the transmissive layer 4, a light incidence surface 42 for receiving the light L from the light source 50, and an inclined surface 43 for reflecting the light L received from the light source 50 and directing it to the transmissive layer 4 side. The inclined surface 43 can control the direction of the light received 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. 1, the light incidence member 40 has a tapered shape in which the thickness decreases as it moves away from the light source 50.

[0052] When multiple light sources 50 are arranged in a row, the laminated film 10 may have multiple light entrance members 40, or may have one light entrance member 40 that has a length that allows light from each of the multiple light sources 50 to be incident in the direction in which the multiple light sources 50 are arranged.

[0053] The "optical incoupling element" disclosed in International Publication No. 2022 / 030544 can be used for the light input member 40. The entire disclosure of International Publication No. 2022 / 030544 is incorporated herein by reference.

[0054] The light incidence 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.

[0055] [Examples and Comparative Examples] Examples and comparative examples will be described below, but the present invention is not limited to these examples.

[0056] <Evaluation method> (Refractive index evaluation) After forming a low refractive index layer on the acrylic film, it was cut to a size of 50 mm x 50 mm and attached to the surface of a glass plate (thickness: 3 mm) with an adhesive layer. The center of the back surface of the glass plate (diameter: about 20 mm) was filled with black marker to prepare a sample in which light is not reflected on the back surface of the glass plate. The adjusted sample was set in an ellipsometer (JA Woollam Japan: VASE) and the refractive index was measured at a wavelength of 550 nm and an incident angle of 50 degrees or more and 80 degrees or less, and the average value was taken as the refractive index.

[0057] (Evaluation of luminous intensity) 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 defines the evaluation indices "A" to "C" for the degree of luminescence. A: Good (little brightness attenuation). B: Fairly good (brightness is lower than A, but the attenuation of brightness is small). C: Poor (brightness attenuation is greater than A and B, and the light becomes darker toward the side opposite the light source 50 in the light guide direction).

[0058] (Evaluation of luminous color) 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 emitted color of the extracted light was evaluated visually. The definitions of "◯" and [×], which are the evaluation indexes of the emitted color, are shown below. 〇: White. ×: The brightness attenuates, and the light becomes darker in the direction opposite to the side where the light source 50 is located (this applies to Comparative Examples 1, 2, and 4 in which the adherend is high-transmittance glass). Or, the illumination light becomes blue and no longer white (this applies to Comparative Example 3 in which the adherend is float glass). High-transmittance glass is glass that absorbs and scatters incident light less. Float glass is glass that absorbs and scatters incident light less than high-transmittance glass.

[0059] (Evaluation of Presence) The presence of the laminate film arranged on the adherend 20 was evaluated visually from the side where light was extracted from the laminate film according to the examples and comparative examples. The definitions of the evaluation indices of presence, "◯" and [×], are shown below. A: The presence of the laminated film is not felt. ×: The presence of the laminated film is felt.

[0060] (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 of "good" and "bad" are defined as follows: ◯: Soft enough to be wound into a roll when long. ×: When the length is long, the film is so hard that it is impossible to wind it up into a roll.

[0061] <Manufacturing method> (Production Example 1: Preparation of low refractive index layer with substrate film) Eight parts of methyltrimethoxysilane were dissolved in 18 parts of dimethyl sulfoxide (DMSO). Four parts of 0.01 mol / L oxalic acid solution were added to this mixture, and the mixture was stirred at room temperature for 30 minutes to hydrolyze the methyltrimethoxysilane. Furthermore, 65 parts of dimethyl sulfoxide, 3 parts of 28% ammonia water, and 2 parts of pure water were added, and the mixture was stirred at room temperature for 15 minutes and heat-aged at 40°C for 20 hours to obtain a gel-like compound.

[0062] The gelled compound obtained by the above heat aging was crushed into granules of several mm to several cm in size, and isopropyl alcohol (IPA) was added in an amount four times the amount of the gel. After lightly stirring, the mixture was left to stand at room temperature for six hours, and the solvent and catalyst in the gel were decanted. The same decantation process was repeated three times to complete the solvent replacement.

[0063] The gel-like compound obtained by solvent replacement was subjected to high-pressure media-less grinding (homogenizer (product name UH-50, manufactured by SMT Co., Ltd.)) to prepare a sol liquid. The volume average particle size, which indicates the particle size variation of the sol liquid at this time, was confirmed with a dynamic light scattering nanotrack particle size analyzer (manufactured by Nikkiso Co., Ltd., product name UPA-EX150 type) and was found to be 0.50 μm or more and 0.70 μm or less. Furthermore, a 1.5 wt% isopropyl alcohol solution of a photobase generating catalyst (Wako Pure Chemical Industries, Ltd.: product name WPBG266) was prepared and added at 0.031 parts to 0.75 parts of the sol particle liquid, and 0.018 parts of 5% bis(trimethoxysilyl)ethane was added to prepare a coating liquid.

[0064] Next, the coating solution for forming the low refractive index layer was applied to a substrate film (PMMA: Poly Methyl Methacrylate, thickness 30 μm) so that the thickness after curing was 1 μm, and the coating solution was heated and dried to cure, thereby obtaining a low refractive index layer (thickness 31 μm) with the substrate film. The refractive index of the obtained low refractive index layer was 1.16.

[0065] (Production Example 2: Preparation of low refractive index layer with substrate film) 13 parts of water were added to 20 parts of alumina sol liquid (4.9% concentration: Kawaken Fine Chemicals), heated at 80°C, and then 3 parts of NH3 were added. The mixture was further heated at 80°C for 10 hours to obtain a gel compound. The same operation as in Production Example 1 was carried out except that this gel compound was used instead of the gel compound in Production Example 1, to obtain a low refractive index layer with a substrate film. The refractive index of the obtained low refractive index layer was 1.24.

[0066] (Production Example 3: Preparation of low refractive index layer with substrate film) A low refractive index layer with a base film was obtained by the same operation as in Production Example 1, except that a thermosetting silicone material (OF-127 manufactured by Shin-Etsu Chemical Co., Ltd.) having a refractive index of 1.41 described in JP 2008-299117 A was used. The refractive index of the obtained low refractive index layer was 1.41.

[0067] (Manufacturing Example 4: Preparation of light extraction part forming layer) According to the method described in JP-A-2013-524288, a light extraction part forming layer having a recess on one of its main surfaces was produced. Specifically, the process is as follows. The surface of a PMMA film (thickness 128 μm) was coated with lacquer (Fine Cure RM-64 manufactured by Sanyo Chemical Industries, Ltd.), a predetermined optical pattern was embossed on the film surface containing the lacquer, and then the lacquer was cured. As a result, a light extraction part forming layer having a cross-sectional shape as shown in FIG. 5 and including a recess having a planar shape as shown in FIG. 6 was produced. Here, FIG. 5 is a cross-sectional view that shows a schematic example of an example of a light extraction part in the examples. FIG. 6 is a plan view that shows a schematic example of an example of a light extraction part in the examples.

[0068] The height (depth) H of the recess as the fabricated light extraction portion was 10 μm, the width W was 10.5 μm, the inclination angle θc of the first inclined surface ISa was 49°, and the inclination angle θd of the second inclined surface ISb was 80°. Furthermore, the pitch Py of the recess in the direction in which the light was guided (e.g., the Y direction) was 300 μm, and the pitch Px in the direction perpendicular to the direction in which the light was guided (e.g., the X direction) was 300 μm.

[0069] Example 1 A fourth adhesive layer 6 (made of polyester resin, thickness 7 μm) was placed on the main surface on which the recesses were formed in the light extraction layer 3 produced in Production Example 4, and a base material 5 (made of PMMA, thickness 30 μm) was laminated via the fourth adhesive layer 6 to obtain a light extraction layer 3 (thickness 165 μm). Furthermore, a transmission layer 4 (made of PMMA, thickness 130 μm) was laminated via a second adhesive layer 8 (manufactured by Nitto Denko Corporation CS9864, thickness 100 μm) on the opposite side of the fourth adhesive layer 6 of the base material 5 to obtain a light guide member 1 (thickness 395 μm). Furthermore, the base material film side of the low refractive index layer 2 with the base material film produced in Production Example 1 was laminated via a third adhesive layer 9 (made of acrylic resin, thickness 10 μm) on the opposite side of the second adhesive layer 8 of the transmission layer 4 to obtain a laminated film 10 (thickness 456 μm). Furthermore, a first adhesive layer 7 (made of acrylic resin, thickness 10 μm) was placed on the opposite side of the low refractive index layer 2 with the base film (30 μm), and the laminated film 10 was placed on highly transmittant glass (manufactured by Nippon Sheet Glass Co., Ltd., thickness 5 mm) as the adherend 20 via the first adhesive layer 7.

[0070] In the manner described above, a laminated film 10 was produced having a light extraction layer 3, a fourth adhesive layer 6, a substrate 5, a second adhesive layer 8, a transparent layer 4, a third adhesive layer 9, a low refractive index layer 2 with a substrate film, and a first adhesive layer 7.

[0071] In this embodiment, as shown in FIG. 1, the laminated film 10 was formed so that the end 3a of the light extraction layer 3 was located inside the end 4a of the transmission layer 4. Then, in a plan view, a light incidence member 40 that allows light from the light source 50 to enter the laminated film 10 was arranged in a region 4b of the transmission layer 4 where the light extraction layer 3 and the transmission layer 4 do not overlap. The length of the region 4b in the Y direction was set to 50 mm. For example, the light incidence member 40 was arranged on the transmission layer 4 by adhesively adhering to the transmission layer 4 via an adhesive layer. In addition, the light source 50 was arranged so that light could be incident on the laminated film 10 through the light incidence member 40. The laminated film 10 arranged on the adherend 20 was evaluated as described above.

[0072] Example 2 The procedure was the same as in Example 1, except that the low refractive index layer with the base film produced in Production Example 2 was used instead of Production Example 1.

[0073] Example 3 The embodiment was the same as the first embodiment, except that a light source 50 was disposed at the end 4 a of the transmissive layer 4 instead of the light entrance member 40 .

[0074] Example 4 The procedure was the same as in Example 1, except that the second adhesive layer 8 was replaced with another second adhesive layer (CS9862 manufactured by Nitto Denko Corporation, thickness 50 μm), and the light extraction portion forming layer 30 was replaced with a thinner light extraction portion forming layer (thickness 60 μm).

[0075] Example 5 The same procedure as in Example 1 was followed except that the transparent layer 4 was replaced with a thin transparent layer (thickness: 30 μm).

[0076] Example 6 The same as in Example 1 was used, except that the transmissive layer 4 was replaced with a thinner transmissive layer (thickness 40 μm), and instead of the light input member 40, a light source 50 was placed at the end of a transmissive layer thinner than the transmissive layer 4.

[0077] Comparative Example 1 The procedure was the same as in Example 1, except that the low refractive index layer with the base film prepared in Production Example 3 was used instead of Production Example 1.

[0078] Comparative Example 2 The same procedure as in Example 1 was repeated except that the low refractive index layer 2 with the base film and the first adhesive layer 7 were not provided.

[0079] Comparative Example 3 The same procedure as in Example 1 was followed except that float glass (manufactured by Nippon Sheet Glass Co., Ltd., thickness 5 mm) was used instead of the high transmittance glass, and the low refractive index layer 2 with the substrate film and the first adhesive layer 7 were not provided.

[0080] Comparative Example 4 The same as in Example 1 was used except that a thicker transmissive layer (thickness 2000 μm) was used instead of the transmissive layer 4, and a light source 50 was placed at the end of a transmissive layer thicker than the transmissive layer 4 instead of the light input member 40.

[0081] Table 1 shows a list of the conditions and evaluation results for each of Examples 1 to 6 and Comparative Examples 1 to 3. In the "Flexibility / Presence" section in Table 1, when both flexibility and presence were "○", the rating was "○", and when at least one of flexibility and presence was "×", the rating was "×". [Table 1]

[0082] As shown in Table 1, in Examples 1 to 4, the "degree of luminescence" was "A," the "luminescent color" was "good," and the "flexibility / presence" was "good." In Examples 5 and 6, the "degree of luminescence" was "B," the "luminescent color" was "good," and the "flexibility / presence" was "good."

[0083] On the other hand, in Comparative Examples 1 and 2, the "degree of luminescence" was "C," the "luminescent color" was "x," and the "flexibility / presence" was "good." In Comparative Example 3, the "degree of luminescence" was "A," the "luminescent color" was "x," and the "flexibility / presence" was "good." In Comparative Example 4, the "degree of luminescence" was "A," the "luminescent color" was "good," and the "flexibility / presence" was "x."

[0084] As described above, it was found that in Examples 1 to 6, laminated films excellent in all of "luminous intensity," "luminous color," and "flexibility / presence" were obtained.

[0085] [Various variations] The laminate film 10 can also have an adherend 20 arranged on the side of the low refractive index layer 2 opposite to the light guide member 1. By having the laminate film 10 have the adherend 20, it is possible to provide the laminate film 10 with the adherend 20 having excellent design properties.

[0086] The adherend 20 is not limited to glass, but may be an electronic substrate such as a liquid crystal cell, a non-light-transmitting member such as a ceiling, a wall, or a floor. The light extraction layer 3 is not limited to extracting the light L to the side opposite to the side where the adherend 20 is located, but may extract the light L to the side where the adherend 20 is located. In this case, if the adherend 20 has high light transmittance, the extracted light L may transmit through the adherend 20, or if the adherend 20 has low light transmittance, the adherend 20 may reflect the light. The light extraction layer 3 may be disposed between the transmission layer 4 and the low refractive index layer 2.

[0087] A pattern layer for improving luminance uniformity may be provided between the transmission layer 4 and the light extraction layer 3. For such a pattern layer, the optical coupling layer disclosed in WO 2022 / 025067 can be used. The entire disclosure of WO 2022 / 025067 is incorporated herein by reference. The pattern layer is formed by a first portion having a lower refractive index than the transmission layer 4 and a second portion having a higher refractive index than the first portion. The first portion may be a low refractive index layer such as the low refractive index layer 2, or may be an air cavity. The second portion may be formed by a tacky adhesive layer, or may be formed by filling the void portion of the low refractive index layer with a material such as a tacky adhesive. From the viewpoint of reducing the presence of the laminated film 10, even when there is a pattern layer, the thickness of the light guide member 1 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.

[0088] A substrate film may be further disposed on the side of the light extraction layer 3 opposite to the side where the transmission layer 4 is located. This substrate film may be a hard coat layer or an anti-reflection layer. Furthermore, a low refractive index layer may be present between the light extraction layer 3 and the substrate film. From the viewpoint of reducing the presence of the laminated film 10, even when these members are present, the thickness of the light guide member 1 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.

[0089] The transmissive layer 4 and the light extraction layer 3 are not limited to being separate films, and may be integrated with the light extraction layer 3. For example, a transmissive layer 4 having patterned recesses formed therein can function as both the transmissive layer 4 and the light extraction layer 3.

[0090] The light extraction layer 3 does not necessarily have to include the substrate 5. The light guide member 1 does not necessarily have to include the second adhesive layer 8.

[0091] In the above description, the low refractive index layer 2 is coated on a base film (not shown), and the first adhesive layer 7, the low refractive index layer 2, the base film (not shown), and the third adhesive layer 9 are arranged in this order. However, the order of the low refractive index layer 2 and the base film (not shown) may be reversed, and the base film (not shown) may be omitted. Alternatively, the low refractive index layer 2 may be directly coated on the light guide member 1, i.e., the transmissive layer 4, and the third adhesive layer 9 and the base film (not shown) may be omitted.

[0092] When handled as a roll, the laminated film of the light guide member and the low refractive index layer may be handled as a roll, or the laminated film of the light guide member, the low refractive index layer, and the first adhesive layer may be handled as a roll. When handled as a roll, a surface protection film having a substrate and an adhesive may be appropriately attached to the surface of the light guide member or the low refractive index layer. Also, a release liner may be attached to the surface of the first adhesive layer.

[0093] 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.

[0094] 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.

[0095] The laminated film according to the embodiment has high designability, and can be used for illuminating the interior or exterior space of a building by combining with a light source and arranging it on architectural components such as glass, windows, walls, floors, and ceilings, while improving the designability of the architectural components. In addition, by arranging it on a partition, it can be used for partitioning an interior or concealing a desired space, while improving the designability of the partition. In addition, by arranging it on a glass substrate of a display device such as a liquid crystal panel or an organic EL (Electro Luminescence) display panel, it can be used for backlight illumination in the display device, while improving the designability of the display device. Furthermore, the laminated film according to the embodiment can provide new uses other than those mentioned above.

[0096] A surface lighting device can also be configured by the laminated film of this embodiment and a light source disposed near an end of the laminated film. Light from the light source may enter the inside of the laminated film from an end face of the laminated film along the lamination direction, or may enter the inside of the laminated film from a face intersecting the end face (the main face of the laminated film). Light from the light source may enter the inside of the laminated film directly without passing through a light incident member or the like, or may enter the inside of the laminated film via a light incident member.

[0097] For example, aspects of the present invention are as follows. <1> The laminated film includes a light-guiding member that guides light incident from a light source, and a low refractive index layer that is arranged on one side of the light-guiding member and has a refractive index of 1.30 or less, the light-guiding member includes a light extraction portion that can extract light guided by the light-guiding member, the light-guiding member has a thickness of 1000 μm or less, and the total thickness from a first surface that is the surface of the light-guiding member on the side opposite to the side on which the low refractive index layer is arranged to a second surface that is the surface of the low refractive index layer on the side opposite to the light-guiding member is 1500 μm or less. <2> a first adhesive layer disposed on the low refractive index layer on the opposite side to the light guide member; <1> 2. The laminated film according to claim 1 . <3> The light guide member includes a light extraction layer including the light extraction portion and a transmission layer that transmits light incident from the light source. <1> From the above <3> 10. The laminated film according to claim 9, wherein the first and second layers are laminated together. <4> The thickness of the transparent layer is 30 μm or more. <3> 2. The laminated film according to claim 1 . <5> The light extraction portion is a plurality of internal spaces provided in the light extraction layer. <3> or the above <4> 2. The laminated film according to claim 1 . <6> a second adhesive layer disposed between the transmission layer and the light extraction layer, and a ratio of a thickness of the second adhesive layer to a thickness of the light guide member is 10% or more; <3> From the above <5> 10. The laminated film according to claim 9, wherein the first and second layers are laminated together. <7> In a plan view, an end of the light extraction layer is located inside an end of the transmission layer. <3> From the above <6> 10. The laminated film according to claim 9, wherein the first and second layers are laminated together. <8> a light entrance member that is disposed in a region of the light transmission layer where the light extraction layer and the light transmission layer do not overlap in a plan view and that allows light from the light source to enter the light entrance member; <7> 2. The laminated film according to claim 1 . <9> The low refractive index layer has an adherend disposed on an opposite side to the light guide member. <1> From the above <8> 10. The laminated film according to claim 9, wherein the first and second layers are laminated together. <10> The above <1> From the above <9> 13. A roll having the laminate film according to any one of claims 1 to 12 wound thereon. [Explanation of symbols]

[0098] 1 Light guide member 11 Page 1 12 Side 2 2. Low refractive index layer 3 Light extraction layer 30 Light extraction part forming layer 31 Light extraction part 3a end 4 Transparent layer 4a end 4b area 5 Base material 6 4th adhesive layer 7 First adhesive layer 8 Second adhesive layer 9 Third adhesive layer 10 Laminated film 20 Adherent 40 Light input member 41 Bottom 42 Light entrance surface 43 Slope 50 light source L light t1 Thickness of light guide member t2 Total thickness of laminated film t3 Thickness of the transparent layer Distance between multiple internal spaces in the DY direction Spacing between multiple internal spaces in the EX direction ISa 1st inclined surface ISb 2nd slope 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 θc, θd Tilt angle

Claims

1. A light guiding member that guides light incident from a light source; a low refractive index layer having a refractive index of 1.30 or less, the low refractive index layer being disposed on one side of the light guide member; the light guide member includes a light extraction portion capable of extracting light guided by the light guide member, The thickness of the light guide member is 1000 μm or less, A laminated film, wherein the total thickness from a first surface, which is the surface of the light-guiding member on the side opposite to the side on which the low refractive index layer is disposed, to a second surface, which is the surface of the low refractive index layer on the side opposite to the light-guiding member, is 1500 μm or less.

2. The laminated film according to claim 1 , further comprising a first adhesive layer disposed on the low refractive index layer on an opposite side to the light guide member.

3. The laminated film according to claim 1 or 2, wherein the light guide member has a light extraction layer including the light extraction portion, and a transmission layer that transmits the light incident from the light source.

4. The laminated film according to claim 3 , wherein the transparent layer has a thickness of 30 μm or more.

5. The laminated film according to claim 3 , wherein the light extraction portion is a plurality of internal spaces provided in the light extraction layer.

6. a second adhesive layer disposed between the light transmitting layer and the light extracting layer; The laminated film according to claim 3 , wherein a ratio of a thickness of the second adhesive layer to a thickness of the light guide member is 10% or more.

7. The laminate film according to claim 3 , wherein an end of the light extraction layer is located more inward than an end of the transmission layer in a plan view.

8. The laminate film according to claim 7 , further comprising a light entrance member disposed in a region of the transmissive layer where the light extraction layer and the transmissive layer do not overlap in a plan view, for allowing light from the light source to enter.

9. The laminate film according to claim 1 or 2, further comprising an adherend arranged on a side of the low refractive index layer opposite to the light guide member.

10. A roll comprising the laminate film according to claim 1 or 2 wound up.

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