Light guide member for illumination device, illumination device and building member

Abstract

To provide a light guide member for illumination device whose transmissivity is higher than before, and whose haze value is small.SOLUTION: A light guide member for illumination device includes: a light guide layer 10 which is the light guide layer having a first main surface, a second main surface on the opposite side from the first main surface, and a light receiving side surface for receiving light emitted from a light source, and in which the first main surface is arranged further on the light emission side than the second main surface; a first low refractive index layer 20A arranged on the first main surface side of the light guide layer, and having a refractive index nL1 which is smaller than a refractive index nGP of the light guide layer; and a light distribution control structure capable of directing part of the light propagating in the light guide layer at least toward the first low refractive index layer. The visible light transmissivity is equal to or greater than 80%, the haze value is below 5%, and the light distribution control structure is provided on the second main surface side of the light guide layer.SELECTED DRAWING: Figure 6A

Description

[Technical field]

[0001] The present invention relates to a light-guiding member for a lighting device, a lighting device, and a building component, and more particularly to a sheet-like or film-like transparent light-guiding member for a lighting device, and a lighting device and a building component including the same. Note that the building component includes both exterior and interior use. [Background technology]

[0002] In recent years, the use of next-generation solid-state lighting (SSL), such as LED lighting, has been increasing. For example, lighting with rich design and entertainment value, called architainment lighting, is being proposed by combining architectural materials with lighting devices.

[0003] For example, Patent Document 1 discloses a one-sided illumination window which has a light source at the end of a plate-shaped transparent substrate, and functions as an illumination device in which light emitted from the light source and guided through the transparent substrate is emitted from one side of the transparent substrate when illuminated, such as at night, and functions as a transparent window when not illuminated, such as during the day.

[0004] A lighting device called a single-sided lighting window described in Patent Document 1 has multiple reflective concave (or convex) surfaces formed on one of the main surfaces of a transparent substrate. Light is guided within the transparent substrate, and the light reflected by the multiple reflective concave (or convex) surfaces is emitted from the other main surface.

[0005] Such multiple reflective concave (or convex) surfaces are easily stained or dusty, or easily scratched. In addition, it may be difficult to control the light distribution (control the distribution of the light distribution direction of the illumination light) using multiple reflective concave (or convex) surfaces, or the transmittance for visible light (hereinafter referred to as "visible light transmittance") may be insufficient, resulting in, for example, a cloudy appearance like ground glass.

[0006] On the other hand, Patent Document 2 discloses an optical device having an optical medium layer (for example, an image display such as a poster, a reflective display, or electronic paper, or a transparent window or wall) and a transparent lighting device that irradiates light onto the optical medium layer. The transparent lighting device has a light guide layer, a low refractive index layer arranged on the observer side of the light guide layer, and an optical function layer (a low refractive index layer, or a layer having a plurality of air cavities) provided between the light guide layer and the optical medium layer. The transparent lighting device described in Patent Document 2 does not have a reflective concave surface (or convex surface) on the outermost surface. In addition, since it has a low refractive index layer arranged on the observer side, light will not leak from there even if dirt adheres to the surface. In addition, Patent Document 3 discloses an LED lighting device including a light guide layer, a low refractive index layer, and a substrate layer. Even if dirt adheres to the surface of the lighting device of Patent Document 3, the light guide efficiency does not decrease.

[0007] In addition, Patent Documents 4 and 5 disclose light distribution structures that utilize total reflection at the interfaces of multiple air cavities. By using the light distribution structures disclosed in Patent Documents 4 and 5, the degree of freedom and accuracy of light distribution control can be improved.

[0008] The disclosures of Patent Documents 2 to 5 are incorporated herein by reference in their entirety. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2019 / 102959 [Patent Document 2] International Publication No. 2019 / 182091 [Patent Document 3] International Publication No. 2019 / 146628 [Patent Document 4] International Publication No. 2011 / 124765 [Patent Document 5] International Publication No. 2019 / 087118 [Patent Document 6] JP 2001-215312 A Summary of the Invention [Problem to be solved by the invention]

[0010] Conventional transparent lighting devices can be used on windows and walls, but their applications are limited due to low transmittance or cloudiness (high haze value). Conventional techniques include a method of forming a dot-like pattern on a light guide plate to extract light, but this method does not provide sufficient transparency in the normal direction. Furthermore, some of these have problems such as the surface being easily soiled or scratched, or the optical properties being significantly changed by the dirt or scratches. In addition, depending on the usage environment, condensation may occur on the surface, resulting in the problem of dirt adhering to the surface. Patent Document 6 discloses an optical film including a layer having a plurality of groove structures with light path conversion slopes, a cover film, and an antifouling layer, but this does not ensure sufficient transparency.

[0011] The present invention has been made to solve at least one of the above problems of conventional transparent lighting devices, and has an object to provide, for example, a lighting device and a light-guiding member for a lighting device that have a higher transmittance and a smaller haze value than conventional devices. Another object of the present invention is to provide a building member equipped with such a lighting device. [Means for solving the problem]

[0012] According to an embodiment of the present invention, there are provided solutions as described in the following items.

[0013] [Item 1] a light guide layer having a first main surface, a second main surface opposite to the first main surface, and a light receiving side surface that receives light emitted from a light source; The light guide layer has a refractive index n GP A refractive index smaller than n L1 A first low refractive index layer having a light distribution control structure capable of directing a part of light propagating in a light guide layer at least toward the first low refractive index layer side or an opposite side to the first low refractive index layer; having A light-guiding member for a lighting device, having a visible light transmittance of 60% or more and a haze value of less than 10%.

[0014] [Item 2] 2. The light-guiding member for a lighting device according to item 1, wherein the light distribution control structure directs at least a part of the light propagating in the light-guiding layer toward the first low refractive index layer.

[0015] [Item 3] 2. The light-guiding member for a lighting device according to item 1, wherein the light distribution control structure directs at least a part of the light propagating in the light-guiding layer toward an opposite side to the first low refractive index layer.

[0016] [Item 4] 4. The light-guiding member for a lighting device according to any one of items 1 to 3, further comprising a first hard coat layer disposed on the opposite side of the first low refractive index layer to the light-guiding layer and having a hardness of pencil hardness H or more.

[0017] [Item 5] 5. The light-guiding member for an illumination device according to any one of items 1 to 4, further comprising a first base material layer on the opposite side of the first low-refractive index layer to the light-guiding layer, and the first hard coat layer is formed on the opposite side of the first base material layer to the first low-refractive index layer. L1 is, for example, 1.05 or more and 1.30 or less.

[0018] [Item 6] 6. The light-guiding member for a lighting device according to any one of items 1 to 5, wherein the light distribution control structure has a plurality of internal spaces that form interfaces that direct light toward the first low refractive index layer side or an opposite side to the first low refractive index layer side by total internal reflection.

[0019] [Item 7] 7. The light-guiding member for a lighting device according to item 6, wherein the light distribution control structure includes a first light distribution control structure in which the plurality of internal spaces are formed in the light-guiding layer.

[0020] [Item 8] Item 7. The light-guiding member for a lighting device according to item 6, wherein the light distribution control structure includes a second light distribution control structure in which the multiple internal spaces are formed in a first direction conversion layer provided between the light-guiding layer and the first low refractive index layer.

[0021] [Item 9] The light guiding layer further includes a first optical coupling layer disposed between the light guiding layer and the first direction changing layer, the first optical coupling layer having a refractive index n GP A refractive index smaller than n C1 Item 9. The light-guiding member for a lighting device according to item 8, comprising a plurality of first low refractive index areas having the following structure:

[0022] [Item 10] Item 7. The light-guiding member for a lighting device according to item 6, wherein the light distribution control structure includes a third light distribution control structure in which the multiple internal spaces are formed in a second direction conversion layer provided on the second main surface of the light-guiding layer.

[0023] [Item 11] 11. The light-guiding member for a lighting device according to any one of items 6 to 10, wherein, when the light-guiding layer is viewed in a plan view from a normal direction to the first main surface, a ratio of an area of ​​the plurality of internal spaces to an area of ​​the light-guiding layer is 30% or less.

[0024] [Item 12] The light guide layer has a refractive index n GP A refractive index smaller than n L2 12. The light-guiding member for a lighting device according to any one of items 1 to 11, further comprising a second low refractive index layer having the following formula:

[0025] [Item 13] The second low refractive index layer is disposed on the opposite side of the light guide layer, and the hardness H GP Hardness H higher than H2 Item 13. The light guiding member for a lighting device according to item 12, further comprising a second hard coat layer having a hardness H H2For example, the pencil hardness is H or more.

[0026] [Item 14] Item 14. The light-guiding member for a lighting device according to item 13, further comprising a second base material layer on an opposite side of the second low refractive index layer to the light-guiding layer, and the second hard coat layer is formed on the opposite side of the second base material layer to the second low refractive index layer.

[0027] The refractive index of the second low refractive index layer is, for example, 1.05 or more and 1.30 or less. The second low refractive index layer having a refractive index of 1.30 or less is formed, for example, using a porous material, and therefore has a hardness H L2 is the hardness H of the light guiding layer GP Lower and more fragile.

[0028] [Item 15] The second optical coupling layer is disposed between the light guide layer and the second direction changing layer, and the second optical coupling layer has a refractive index n GP A refractive index smaller than n C2 Item 11. The light-guiding member for a lighting device according to item 10, comprising a plurality of second low refractive index areas having the following structure:

[0029] [Item 16] The light guiding member for a lighting device according to item 13 or 14, which indirectly cites item 4, wherein a haze value of the first hard coat layer is greater than a haze value of the second hard coat layer. The first hard coat layer and / or the second hard coat layer contains, for example, particles.

[0030] [Item 17] 17. The light-guiding member for a lighting device according to any one of items 1 to 16, further comprising an antifouling layer having water repellency and / or oil repellency (or hydrophilicity) as an outermost layer on the first principal surface side or the second principal surface side.

[0031] [Item 18] Item 18. The light-guiding member for a lighting device according to item 17, further comprising an antireflection layer provided on the light-guiding layer side of the antifouling layer.

[0032] [Item 19] A light-guiding member for a lighting device according to any one of items 1 to 18, a light source that emits light toward the light receiving side surface; A lighting device comprising:

[0033] [Item 20] Item 19. A building member comprising the light-guiding member for a lighting device according to any one of items 1 to 18. Effect of the Invention

[0034] According to an embodiment of the present invention, there is provided a lighting device having a higher transmittance and a smaller haze value than conventional lighting devices, and according to another embodiment of the present invention, there is provided a building member including such a lighting device. [Brief description of the drawings]

[0035] [Figure 1A] 1 is a schematic cross-sectional view of a lighting device 100A_L according to an embodiment of the present invention. [Figure 1B] 1 is a schematic cross-sectional view of a lighting device 100B_L according to an embodiment of the present invention. [Figure 2A] 1 is a schematic cross-sectional view of a lighting device 200A_L according to an embodiment of the present invention. [Figure 2B] 1 is a schematic cross-sectional view of a lighting device 200B_L according to an embodiment of the present invention. [Diagram 3] 1 is a schematic cross-sectional view of a lighting device 300A_L according to an embodiment of the present invention. [Figure 4A] 1 is a schematic cross-sectional view of a light-guiding member 100A according to an embodiment of the present invention. [Figure 4B] 1 is a schematic cross-sectional view of a light-guiding member 100B according to an embodiment of the present invention. [Figure 5A] 1 is a schematic cross-sectional view of a light-guiding member 200A according to an embodiment of the present invention. [Figure 5B] 1 is a schematic cross-sectional view of a light-guiding member 200B according to an embodiment of the present invention. [Figure 6A] 1 is a schematic cross-sectional view of a light-guiding member 210A according to an embodiment of the present invention. [Figure 6B] 11 is a schematic cross-sectional view of a light-guiding member 210B according to an embodiment of the present invention. [Figure 7A] 1 is a schematic cross-sectional view of a light-guiding member 220A according to an embodiment of the present invention. [Figure 7B] 11 is a schematic cross-sectional view of a light-guiding member 220B according to an embodiment of the present invention. [Figure 8] 1 is a schematic cross-sectional view of a light-guiding member 100AD according to an embodiment of the present invention. [Figure 9] 1 is a schematic cross-sectional view of a light-guiding member 210AD according to an embodiment of the present invention. [Figure 10] 1 is a schematic cross-sectional view of a light-guiding member 200AD according to an embodiment of the present invention. [Figure 11] 11 is a schematic cross-sectional view of a light-guiding member 220AD according to an embodiment of the present invention. [Figure 12A] FIG. 11 is a schematic cross-sectional view of a light guide member 200AD_a of the embodiment. [Figure 12B] FIG. 11 is a schematic cross-sectional view of a light guide member 200BD_a of the embodiment. [Figure 13A] FIG. 11 is a schematic cross-sectional view of a light-guiding member 220AD_a of the embodiment. [Figure 13B] FIG. 13 is a schematic cross-sectional view of a light-guiding member 220AD_b of the embodiment. [Figure 13C] FIG. 11 is a schematic cross-sectional view of a light-guiding member 220BD_b of the embodiment. [Figure 14A] 2 is a schematic plan view of a shaping film 62 constituting a direction changing layer of a light-guiding member according to an embodiment of the present invention. FIG. [Figure 14B] 2 is a schematic cross-sectional view of a shaping film 62. FIG. [Figure 15] 2 is a schematic cross-sectional view showing a recess 64 of a shaping film 62. FIG. [Figure 16] FIG. 2 is a schematic plan view for explaining the distribution of a low refractive index region 80a. [Figure 17] 11 is a schematic cross-sectional view of a light guide member 910A of a comparative example. [Figure 18] 13 is a schematic cross-sectional view of a light-guiding member 920A of a comparative example. [Figure 19A] 11 is a schematic plan view showing a recess 94 of a shaping film 92 used in Comparative Example 3. FIG. [Figure 19B] 11 is a schematic cross-sectional view showing a recess 94 of a shaping film 92 used in Comparative Example 3. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036] Hereinafter, a light-guiding member for a lighting device, a lighting device, and a building component according to embodiments of the present invention will be described with reference to the drawings. The light-guiding member for a lighting device, a lighting device, and a building component according to the embodiments of the present invention are not limited to those exemplified below.

[0037] [Light-guiding member for lighting device and lighting device] First, examples of a light-guiding member for a lighting device and a lighting device according to embodiments of the present invention will be described with reference to the drawings.

[0038] 1A shows a schematic cross-sectional view of an illumination device 100A_L according to an embodiment of the present invention. The illumination device 100A_L includes a light source LS and a light guide member 100A that receives light emitted from the light source LS, propagates the light in the Y direction, and emits the light in the Z direction. Of course, the light propagation direction has a variation (distribution) from the Y direction, and the light emission direction also has a variation (distribution) from the Z direction. The light guide member 100A has a visible light transmittance of 60% or more. Here, light having a wavelength of 380 nm or more and 780 nm or less is defined as visible light.

[0039] The light guide layer 10A of the light guide member 100A has a first main surface, a second main surface opposite to the first main surface, and a light-receiving side surface that receives light emitted from a light source LS. In FIG. 1A, the upper main surface is the first main surface, and the lower main surface is the second main surface. The light source LS is, for example, an LED device, and a plurality of LED devices may be arranged for use. In addition, a coupling optical system may be provided between the light source LS and the light guide layer 10A to efficiently guide the light emitted from the light source LS to the light guide layer 10A.

[0040] The light guide member 100A is disposed on the first main surface side of the light guide layer 10A, and has a refractive index nGP A refractive index smaller than n L1 and a first hard coat layer 40A having a pencil hardness of H or more and disposed on the side of the first low refractive index layer 20A opposite to the light guide layer 10A.

[0041] The light guide layer 10A is made of a known material having a high transmittance for visible light. The light guide layer 10A is made of, for example, an acrylic resin such as polymethyl methacrylate (PMMA), a polycarbonate (PC) resin, a cycloolefin resin, or glass (for example, quartz glass, non-alkali glass, or borosilicate glass). The refractive index n of the light guide layer 10A is GP is, for example, 1.40 or more and 1.80 or less. The refractive index is measured by an ellipsometer at a wavelength of 550 nm unless otherwise specified. The thickness of the light guide layer 10A can be appropriately set depending on the application. The thickness of the light guide layer 10A is, for example, 0.05 mm or more and 50 mm or less.

[0042] The refractive index n of the first low refractive index layer 20A L1 is preferably 1.30 or less, more preferably 1.20 or less, and even more preferably 1.15 or less. The first low refractive index layer 20A is preferably a solid, and the refractive index is preferably 1.05 or more. The difference between the refractive index of the light guide layer 10A and the refractive index of the first low refractive index layer 20A is preferably 0.20 or more, more preferably 0.23 or more, and even more preferably 0.25 or more. The first low refractive index layer 20A having a refractive index of 1.30 or less may be formed, for example, using a porous material. The thickness of the first low refractive index layer 20A is, for example, 0.3 μm or more and 5 μm or less.

[0043] When the low refractive index layer 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 having 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 having excellent strength can be formed. The porosity is a value calculated from the refractive index measured by an ellipsometer using the Lorentz-Lorenz's formula.

[0044] For the low refractive index layer, for example, a low refractive index layer having voids disclosed in Patent Document 3 can be used. The entire disclosure of Patent Document 3 is incorporated herein by reference. Specifically, the low refractive index layer having voids includes silica particles, silica particles having micropores, approximately spherical particles such as 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 part 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 single 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.

[0045] Methods for obtaining a low refractive index layer having voids include, for example, methods described in JP2010-189212A, JP2008-040171A, JP2006-011175A, WO2004 / 113966A, and references thereto. The disclosures of JP2010-189212A, JP2008-040171A, JP2006-011175A, and WO2004 / 113966A are all incorporated herein by reference.

[0046] A porous silica body can be suitably used as a low refractive index layer having voids. The porous silica body is produced, for example, by the following method. A method of hydrolyzing and polycondensing at least one of a silicon compound, hydrolyzable silanes and / or silsesquioxane, and a partial hydrolyzate and a dehydration condensate thereof, a method of using porous particles and / or hollow fine particles, a method of producing 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 resulting crushed body, that is, microporous particles, are chemically bonded to each other with a catalyst or the like, and the like. However, the low refractive index layer is not limited to a porous silica body, and the manufacturing method is not limited to the exemplified manufacturing method, and any manufacturing method may be used to produce it. However, the porous layer is not limited to a porous silica body, and the manufacturing method is not limited to the exemplified manufacturing method, and any manufacturing method may be used to produce it. The silsesquioxane is (RSiO 1.5 Silsesquioxane is a silicon compound whose basic structural unit is a silsesquioxane (R is a hydrocarbon group). Strictly speaking, it is different from silica whose basic structural unit is SiO2. However, it has something in common with silica in that it has a network structure cross-linked by siloxane bonds. Therefore, here, porous materials containing silsesquioxane as a basic structural unit are also referred to as porous silica materials or silica-based porous materials.

[0047] 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 bodies of gel-like silicon compound. The silica porous body can be formed, for example, by applying a coating liquid containing pulverized bodies of gel-like silicon compound to a substrate. The pulverized bodies of gel-like silicon compound can be chemically bonded (for example, siloxane bonded) by, for example, the action of a catalyst, light irradiation, heating, etc.

[0048] When the first low refractive index layer 20A is present, the interface between the light guide layer 10A and the first low refractive index layer 20A becomes an interface that can totally reflect the light propagating in the light guide layer 10A, and is not affected by the state on the first low refractive index layer 20A. When the first low refractive index layer 20A is not present and the surface of the light guide layer 10A is exposed, total reflection occurs at the interface between the surface of the light guide layer 10A and the air. When the surface of the light guide layer 10A becomes dirty, total reflection may not occur in the part of the surface where the dirt is attached. This causes problems such as light leaking from the part of the surface where the dirt is attached and / or a change in the distribution of light propagating in the light guide layer 10A. That is, the first low refractive index layer 20A can improve the antifouling property of the surface of the light guide member 100A. This effect is the same even when the first hard coat layer 40A is formed on the first low refractive index layer 20A.

[0049] Hardness H of the first hard coat layer 40A H1 The hardness H of the first hard coat layer 40A is preferably H or more, more preferably 2H or more, and even more preferably 4H or more, in terms of pencil hardness. H1 Although there is no particular upper limit, the pencil hardness is preferably 6H or less, and more preferably 5H or less. The pencil hardness is measured by a method in accordance with the "Pencil Hardness Test" of JIS K 5400. The hardness H of the light guide layer 10A is GP is, for example, B. The thickness of the first hard coat layer 40A is preferably 1 μm or more and 30 μm or less, more preferably 2 μm or more and 20 μm or less, and further preferably 3 μm or more and 15 μm or less. If the thickness of the first hard coat layer 40A is in such a range, it has good scratch resistance.

[0050] The first low refractive index layer 20A has a hardness H GP Hardness H higher than L1 In this case, the first low refractive index layer 20A may also function as the first hard coat layer 40A. In other words, the first hard coat layer 40A may be omitted. In this case, the hardness H L1The pencil hardness is preferably H or more, more preferably 2H or more, and even more preferably 4H or more. There is no upper limit, but it is preferably 6H or less, and more preferably 5H or less.

[0051] The first hard coat layer 40A may be made of any suitable material as long as it satisfies the above-mentioned characteristics. The first hard coat layer 40A is, for example, a cured layer of a thermosetting resin or an ionizing radiation (for example, visible light, ultraviolet light) curable resin. Examples of such curable resins include acrylates such as urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate, silicon resins such as polysiloxane, unsaturated polyester, and epoxy resin. The first hard coat layer 40A can be formed, for example, by applying a material containing a solvent and a curable compound to the surface of the target substrate and curing the material. Details of a hard coat layer that is preferably used as the first hard coat layer 40A are described, for example, in JP 2011-237789 A. The entire disclosure of JP 2011-237789 A is incorporated herein by reference.

[0052] The light guide member 100A has a light distribution control structure that can direct at least a part of light propagating in the light guide layer 10A toward the first low refractive index layer 20A. The light distribution control structure has a plurality of internal spaces 14A that form an interface that directs light toward the first low refractive index layer 20A by total internal reflection. The internal space 14A is also called an optical cavity. In the light guide member 100A, a plurality of internal spaces 14A are formed in the light guide layer 10A. As shown in the figure, for example, the internal space 14A has a triangular cross-sectional shape (perpendicular to the X direction and parallel to the YZ plane) with an apex angle on the first low refractive index layer 20A side (Z direction, upper side in the figure), and directs light propagating in the Y direction in the light guide layer 10A toward the first low refractive index layer 20A side. The cross-sectional shape of the internal space 14A is not limited to this, and may be a trapezoid or the like as long as it has an interface that directs light propagating in the Y direction toward the first low refractive index layer 20A side. The light distribution control structure formed in light guide layer 10A may be referred to as a first light distribution control structure.

[0053] The light guide member 100A has a first light distribution control structure formed by a plurality of internal spaces 14A in the light guide layer 10A, and therefore the visible light transmittance can be 60% or more and the haze value can be less than 10%. In addition, as described below, the light distribution, emission efficiency, and luminance distribution of the emitted light can be controlled by adjusting the shape and arrangement of the plurality of internal spaces 14A. The plurality of internal spaces 14A are typically voids filled with air (air cavities). However, the air cavities may be filled with a material having a lower refractive index than the light guide layer 10A instead of air.

[0054] The light-guiding member 100A has a plurality of internal spaces 14A arranged regularly or randomly along the main surface. The size of the internal spaces 14A can be appropriately selected within a range that allows installation inside the light-guiding layer 10A. The light-guiding layer including the internal spaces 14A therein is not particularly limited, and the light-guiding layers disclosed in Patent Documents 2, 4, and 5 and International Publication No. WO 2011 / 127187 can be used, for example. The disclosures of these publications are incorporated herein by reference in their entirety.

[0055] The light guide layer 10A is produced, for example, by bonding a first film having no pattern formed thereon to a second film having a desired fine pattern formed thereon by a lamination method or by using an adhesive (including a pressure-sensitive adhesive).

[0056] 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 the material or refractive index value. Micro / nano dispensing, dosing, direct "writing", discrete laser sintering, micro-electrical discharge machining (micro-EDM), or micromachining, micromolding, imprinting, embossing, and the like may also be used.

[0057] In order to obtain a good visible light transmittance and haze value, it is preferable that the ratio (occupancy rate) of the area of ​​the plurality of internal spaces 14A to the area of ​​the light guide layer 10A is 30% or less when the light guide layer 10A is viewed in a plan view from the normal direction of the main surface. The occupancy rate of the internal spaces 14A may be uniform, or may increase with increasing distance from the light source LS so that the brightness does not decrease even if the distance from the light source LS increases. As will be described later with a specific example, it is preferable that the occupancy rate of the internal spaces 14A is uniform. It is preferable that the occupancy rate of the internal spaces 14A is 1% or more from the viewpoint of obtaining a good brightness. The occupancy rate of the internal spaces 14A 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.

[0058] The above-mentioned features of the light distribution control structure are not limited to the multiple internal spaces 14A formed in the light guide layer 10A exemplified here, but are common to various light distribution control structures described later. As a light distribution control structure constituted by multiple internal spaces, for example, a light distribution structure described in Patent Document 5 can be used.

[0059] 1B is a schematic cross-sectional view of a lighting device 100B_L according to an embodiment of the present invention. The lighting device 100B_L differs from the lighting device 100A_L shown in FIG. 1A in that it includes a light-guiding member 100B that receives light emitted from a light source LS, propagates the light in the Y direction, and emits the light in the -Z direction.

[0060] The light guide layer 10B of the light guide member 100B has a light distribution control structure that can direct at least a part of the light propagating in the light guide layer 10B to the opposite side to the first low refractive index layer 20A. The light distribution control structure has a plurality of internal spaces 14B that form interfaces that direct the light to the opposite side to the first low refractive index layer 20A by total internal reflection. As shown in the figure, for example, the internal space 14B has a triangular cross-sectional shape (perpendicular to the X direction, parallel to the YZ plane) with an apex angle on the opposite side to the first low refractive index layer 20A (-Z direction, lower side in the figure), and directs the light propagating in the Y direction in the light guide layer 10B to the opposite side to the first low refractive index layer 20A. The cross-sectional shape of the internal space 14B is not limited to this, and may be a trapezoid or the like as long as it has an interface that directs the light propagating in the Y direction to the opposite side to the first low refractive index layer 20A. In this way, the light emission direction can be changed by changing the cross-sectional shape of the internal space 14B (for example, the direction of the apex angle of the triangle).

[0061] FIG. 2A shows a schematic cross-sectional view of a lighting device 200A_L according to an embodiment of the present invention. The light guide member 200A of the lighting device 200A_L has a first direction conversion layer 60A formed between the light guide layer 10 and the first low refractive index layer 20A, and a plurality of internal spaces 64A constituting the light distribution control structure are formed in the first direction conversion layer 60A. The first direction conversion layer 60A can direct at least a part of the light propagating in the light guide layer 10 toward the first low refractive index layer 20A. The light distribution control structure formed in the first direction conversion layer 60A may be referred to as a second light distribution control structure. The internal space 64A may have various cross-sectional shapes, similar to the internal space 14A.

[0062] FIG. 2B shows a schematic cross-sectional view of a lighting device 200B_L according to an embodiment of the present invention. The light guide member 200B of the lighting device 200B_L has a first direction conversion layer 60B formed between the light guide layer 10 and the first low refractive index layer 20A, and a plurality of internal spaces 64B constituting the light distribution control structure are formed in the first direction conversion layer 60B. The first direction conversion layer 60B can direct at least a part of the light propagating in the light guide layer 10 to the opposite side (-Z direction) from the first low refractive index layer 20A. The light distribution control structure formed in the first direction conversion layer 60B may be referred to as a second light distribution control structure. The internal space 64B may have various cross-sectional shapes, similar to the internal space 14B.

[0063] FIG. 3 shows a schematic cross-sectional view of another lighting device 300A_L according to an embodiment of the present invention. The light guide member 300A of the lighting device 300A_L has a first direction change layer 70A formed between the light guide layer 10 and the first low refractive index layer 20A, and a plurality of convex portions 74A of the first direction change layer 70A constitute a light distribution control structure. The first direction change layer 70A including the plurality of convex portions 74A may be, for example, a known prism sheet. The plurality of convex portions 74A direct light propagating in the Y direction in the light guide layer 10 toward the first low refractive index layer 20A side (Z direction). The cross-sectional shape of the convex portion 74A is, for example, a triangle, but is not limited thereto and may be a trapezoid or the like. By changing the cross-sectional shape of the convex portion 74A, the light propagating in the Y direction can also be directed toward the opposite side (-Z direction) to the first low refractive index layer 20A. Moreover, instead of providing the first direction changing layer 70A, a plurality of convex portions (prism portions) may be formed directly on the surface of the light guide layer 10A.

[0064] Next, the structure of the light guide member will be described in detail. In the following, an example will be described in which the light distribution control structure has a plurality of internal spaces (14A) that form an interface that directs light toward the first low refractive index layer by total internal reflection, or a plurality of internal spaces (14B) that form an interface that directs light toward the opposite side to the first low refractive index layer by total internal reflection.

[0065] Fig. 4A shows a cross-sectional view of the light-guiding member 100A of the illumination device 100A_L shown in Fig. 1A, and Fig. 4B shows a cross-sectional view of the light-guiding member 100B of the illumination device 100B_L shown in Fig. 1B. Fig. 5A shows a cross-sectional view of the light-guiding member 200A of the illumination device 200A_L shown in Fig. 2A, and Fig. 5B shows a cross-sectional view of the light-guiding member 200B of the illumination device 200B_L shown in Fig. 2B.

[0066] As shown in Fig. 4A, in the light guiding member 100A, a plurality of internal spaces 14A formed in the light guiding layer 10A constitute the light distribution control structure, and as shown in Fig. 4B, in the light guiding member 100B, a plurality of internal spaces 14B formed in the light guiding layer 10B constitute the light distribution control structure. As shown in Fig. 5A, in the light guiding member 200A, a plurality of internal spaces 64A formed in the first direction changing layer 60A formed on the light guiding layer 10 constitute the light distribution control structure, and as shown in Fig. 5B, in the light guiding member 200B, a plurality of internal spaces 64B formed in the first direction changing layer 60B formed on the light guiding layer 10 constitute the light distribution control structure. The refractive index n of the first direction changing layers 60A and 60B D1 is the refractive index n of the light guide layer 10 GP The difference (absolute value) in the refractive indices is preferably 0.15 or less, and more preferably 0.1 or less. GP and the refractive index n of the first low refractive index layer 20A L1 4A and 4B ), and the refractive index n D1 and the refractive index n of the first low refractive index layer 20A L1 The difference between these (FIGS. 5A and 5B) is preferably 0.2 or more, and more preferably 0.25 or more. By adjusting this difference, the critical angle at which total reflection occurs can be controlled.

[0067] The light distribution control structure having a plurality of internal spaces 14A, 14B, 64A, 64B directs the emission direction of the light to the Z direction (internal space 14A, 64A) or the -Z direction (internal space 14B, 64B) by totally reflecting the light propagating in the light guide layer 10A, 10B or the first direction conversion layer 60A, 60B at the interface formed by the internal spaces 14A, 14B, 64A, 64B. In contrast, in the first direction conversion layer 70A shown in FIG. 3, which is made of, for example, a known prism sheet, a part of the light propagating in the first direction conversion layer 70A is totally reflected at the interface with the first low refractive index layer 20A and returned to the first direction conversion layer 70A. In this way, the light distribution control structure having the internal spaces 14A, 14B, 64A, 64B has a higher light utilization efficiency than a light distribution control structure such as a known prism sheet. Furthermore, the light distribution can be controlled by adjusting the cross-sectional shape (for example, angles θa and θb of the inclined surfaces in FIG. 15), size, arrangement density, and distribution of the internal spaces 14A, 14B, 64A, and 64B.

[0068] On the other hand, the visible light transmittance and haze value of the light guide member 100A, 100B, 200A or 200B can be controlled by adjusting the cross-sectional shape, size, arrangement density, and distribution of the multiple internal spaces 14A, 14B, 64A, and 64B of the light distribution control structure. The visible light transmittance of the light guide members 100A, 100B, 200A, and 200B is 60% or more, preferably 65% ​​or more, 70% or more, 75% or more, or 80% or more, and the haze value is less than 10%, 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 is measured using a haze meter as described in the following examples.

[0069] In order to obtain a good visible light transmittance and haze value, it is preferable that the ratio (occupancy rate) of the area of ​​the plurality of internal spaces 14A, 14B, 64A, 64B to the area of ​​the light guide layer 10A, 10B, or 10 is 30% or less when the light guide layer 10A, 10B, or 10 is viewed in plan from the normal direction of the main surface. The occupancy rate of the internal spaces 14A, 14B, 64A, 64B may be uniform, or may increase with increasing distance from the light source LS so that the luminance does not decrease even if the distance from the light source LS increases. As will be described later with a specific example, it is preferable that the occupancy rate of the internal spaces 14A, 14B, 64A, 64B is uniform. It is preferable that the occupancy rate of the internal spaces 14A, 14B, 64A, 64B is 1% or more from the viewpoint of obtaining a good luminance. The occupied area ratio of the internal spaces 14A, 14B, 64A, and 64B is preferably 1% or more and 30% or less, with the upper limit being more preferably 25% or less, and in order to obtain a high visible light transmittance, it is preferably 10% or less, and more preferably 5% or less.

[0070] In addition, the size and density of the internal spaces 14A, 14B, 64A, and 64B affect the haze value. The size (length L, width W: see FIG. 14A and FIG. 14B) of the internal spaces 14A, 14B, 64A, and 64B is, for example, preferably 10 μm or more and 500 μm or less, and preferably 1 μm or more and 100 μm or less, and the width W is, for example, preferably 1 μm or more and 100 μm or less. In addition, from the viewpoint of light extraction efficiency, the height H is preferably 1 μm or more and 100 μm or less. It is preferable that the multiple internal spaces 14A, 14B, 64A, and 64B are distributed discretely and uniformly, and for example, as shown in FIG. 14A, 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.

[0071] Next, other configuration examples of the light-guiding member according to the embodiments of the present invention will be described with reference to Figures 6A, 6B, 7A, 7B, and 8 to 11, but the present invention is not limited to these and can be combined in various ways.

[0072] 6A, a light distribution control structure (sometimes referred to as a third light distribution control structure) is configured by a plurality of internal spaces 64A formed in a second direction changing layer 60A provided on the second main surface of the light guide layer 10. The second direction changing layer 60A having the internal spaces 64A directs at least a part of the light propagating in the light guide layer 10 toward the first low refractive index layer 20A side (Z direction).

[0073] 6B, a light distribution control structure (sometimes referred to as a third light distribution control structure) is configured by a plurality of internal spaces 64B formed in a second direction changing layer 60B provided on the second main surface of the light guide layer 10. The second direction changing layer 60B having the internal spaces 64B directs at least a part of the light propagating in the light guide layer 10 in the opposite direction (−Z direction) to the first low refractive index layer 20A.

[0074] The light guide member 220A shown in FIG. 7A further includes a first optical coupling layer 80 in addition to the light guide member 200A shown in FIG. 5A. The first optical coupling layer 80 is provided between the light guide layer 10 and the first direction changing layer 60A. The first optical coupling layer 80 has a refractive index n GP A refractive index smaller than n C1 The first optical coupling layer 80, which is made up of the plurality of first low refractive index regions 80a, guides the light propagating through the light guide layer 10 to the first direction conversion layer 60A more selectively and efficiently. The refractive index n of the first low refractive index regions 80a C1 is preferably 1.05 or more and 1.30 or less, and more preferably 1.05 or more and 1.25 or less.

[0075] The light guide member 220B shown in FIG. 7B further includes a first optical coupling layer 80 in addition to the light guide member 200B shown in FIG. 5B. The first optical coupling layer 80 is provided between the light guide layer 10 and the first direction changing layer 60B. The first optical coupling layer 80 has a refractive index n GP A refractive index smaller than n C1The first optical coupling layer 80, which is composed of the plurality of first low refractive index regions 80a, guides the light propagating through the light guide layer 10 to the first direction changing layer 60B more selectively and efficiently.

[0076] The light guide member 100AD shown in FIG. 8 is the same as the light guide member 100A shown in FIG. 1A, except that a second main surface side of the light guide layer 10A is further provided with a refractive index n GP A refractive index smaller than n L2 and a second low refractive index layer 20B having a hardness H GP Hardness H higher than H2 The second low refractive index layer 20B and the second hard coat layer 40B may have the same characteristics as the first low refractive index layer 20A and the first hard coat layer 40A, respectively. By providing the second low refractive index layer 20B and the second hard coat layer 40B on the second main surface side of the light guide layer 10A, the above-mentioned effect can be obtained on the second main surface side as well. The light guide member 100AD has a light guide layer 10A in which a plurality of internal spaces 14A are formed, and therefore emits light in the Z direction. By arranging a light guide layer 10B (see FIG. 1B, for example) having a plurality of internal spaces 14B instead of the light guide layer 10A of the light guide member 100AD, a light guide member that emits light in the -Z direction can be obtained.

[0077] The light guide member 210AD shown in FIG. 9 further includes a second conductive layer 211 having a refractive index n GP A refractive index smaller than n L2 and a second hard coat layer 40B having a pencil hardness of H or more, disposed on the opposite side of the second low refractive index layer 20B from the light guide layer 10. The light guide member 210AD has a second direction changing layer 60A in which a plurality of internal spaces 64A are formed, and emits light in the Z direction. By disposing a second direction changing layer 60B (see FIG. 6B, for example) having a plurality of internal spaces 14B instead of the second direction changing layer 60A of the light guide member 210AD, a light guide member that emits light in the -Z direction can be obtained.

[0078] The light guide member 200AD shown in FIG. 10 further includes a second conductive layer 211 having a refractive index n GP A refractive index smaller than n L2 and a hardness H GP Hardness H higher than H2 The light guiding member 200AD further includes a second hard coat layer 40B having a plurality of internal spaces 64A. The light guiding member 200AD includes a second direction changing layer 60A having a plurality of internal spaces 64A, and thus emits light in the Z direction. By disposing a second direction changing layer 60B (see FIG. 5B, for example) having a plurality of internal spaces 64B instead of the second direction changing layer 60A of the light guiding member 200AD, a light guiding member that emits light in the -Z direction can be obtained.

[0079] The light-guiding member 220AD shown in FIG. 11 is a light-guiding member 220A shown in FIG. 7A, which further includes a second main surface side of the light-guiding layer 10 having a refractive index n GP A refractive index smaller than n L2 and a hardness H GP Hardness H higher than H2 The light guiding member 220AD further includes a second hard coat layer 40B having a plurality of internal spaces 64A. The light guiding member 220AD includes a second direction changing layer 60A having a plurality of internal spaces 64A, and thus emits light in the Z direction. By disposing a second direction changing layer 60B (see FIG. 7B, for example) having a plurality of internal spaces 64B instead of the second direction changing layer 60A of the light guiding member 220AD, a light guiding member that emits light in the -Z direction can be obtained.

[0080] The light guide member according to the embodiment of the present invention may be modified in various ways. For example, an antiglare hard coat layer having an uneven surface may be formed by mixing particles into the material for forming the first hard coat layer and / or the second hard coat layer. This allows the haze value of the light guide member to be controlled. Examples of the particles include inorganic particles and organic particles. The inorganic particles are not particularly limited, and examples thereof include silicon oxide particles, titanium oxide particles, aluminum oxide particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, and calcium sulfate particles. The organic particles are not particularly limited, and examples thereof include polymethyl methacrylate resin powder (PMMA particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, and polyethylene fluoride resin powder. These inorganic particles and organic particles may be used alone or in combination of two or more types.

[0081] The mass average particle size of the particles mixed into the material for forming the first hard coat layer and / or the second hard coat layer is preferably in the range of 0.5 μm to 8.0 μm in terms of imparting good antiglare properties. The mass average particle size of the particles is more preferably in the range of 2.0 μm to 6.0 μm, and even more preferably in the range of 3.0 μm to 6.0 μm. It is also preferable that the mass average particle size of the particles is in the range of 30% to 80% of the thickness of the first hard coat layer and / or the second hard coat layer. The mass average particle size of the particles can be measured by the Coulter counter method. For example, a particle size distribution measuring device using the pore electrical resistance method (product name: Coulter Multisizer, manufactured by Beckman Coulter, Inc.) is used to measure the number and volume of particles by measuring the electrical resistance of the electrolyte corresponding to the volume of the particles when the particles pass through the pores, and the mass average particle size is calculated.

[0082] The shape of the particles is not particularly limited, and may be, for example, roughly spherical like beads, or irregularly shaped like powder, but roughly spherical particles are preferred, more preferably roughly spherical microparticles with an aspect ratio of 1.5 or less, and most preferably spherical particles.

[0083] The mixing ratio of the particles is preferably 5 parts by mass or more and 20 parts by mass or less, more preferably 5 parts by mass or more and 17 parts by mass or less, based on 100 parts by mass of the hard coat layer forming material. For example, the antiglare hard coat layer described in JP2013-178534A can be suitably used. The entire disclosure of JP2013-178534A is incorporated herein by reference.

[0084] Furthermore, an antifouling layer having water repellency and / or oil repellency (hydrophilicity) may be further provided on one or both main surfaces as the outermost layer of the light guide member. The configuration of the antifouling layer is appropriately selected depending on the application. The antifouling layer is formed using a known material. As a material constituting the antifouling layer, a silicone-based compound or a fluorine-containing compound is preferable. Among them, a fluorine-containing compound has excellent water repellency and can exhibit high antifouling properties, and a fluorine-based polymer containing a perfluoropolyether skeleton is particularly preferable. From the viewpoint of enhancing antifouling properties, a perfluoropolyether having a main chain structure that can be rigidly arranged in parallel is particularly preferable. As a structural unit of the main chain skeleton of the perfluoropolyether, a perfluoroalkylene oxide that may have a branch having 1 to 4 carbon atoms is preferable, and examples thereof include perfluoromethylene oxide (-CF2O-), perfluoroethylene oxide (-CF2CF2O-), perfluoropropylene oxide (-CF2CF2CF2O-), and perfluoroisopropylene oxide (-CF(CF3)CF2O-).

[0085] The thickness of the antifouling layer is preferably 3 nm or more and 15 nm or less, and more preferably 3 nm or more and 10 nm or less.

[0086] The method for forming the antifouling layer can be a physical vapor deposition method such as vapor deposition or sputtering, a chemical vapor deposition method, a reverse coating method, a die coating method, a gravure coating method, or other wet coating method, depending on the material to be formed. For example, the antifouling layer described in JP 2020-067582 A can be suitably used. The entire disclosure of JP 2020-067582 A is incorporated herein by reference.

[0087] An antireflection layer may be formed on the light guide layer side of the antifouling layer. The antireflection layer may be, for example, a multilayer laminate made of a plurality of thin films having different refractive indices. Examples of materials for the thin films constituting the antireflection layer include metal oxides, nitrides, fluorides, etc.

[0088] The antireflection layer is preferably an alternate laminate of high and low refractive index layers. The high refractive index layer has a refractive index of, for example, 1.9 or more, preferably 2.0 or more. Examples of high refractive index materials include titanium oxide, niobium oxide, zirconium oxide, tantalum oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and antimony-doped tin oxide (ATO). Among these, titanium oxide or niobium oxide is preferred. The low refractive index layer has a refractive index of, for example, 1.6 or less, preferably 1.5 or less. Examples of low refractive index materials include silicon oxide, titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Among these, silicon oxide is preferred. In particular, it is preferred to alternately laminate a niobium oxide (Nb2O5) thin film as the high refractive index layer and a silicon oxide (SiO2) thin film as the low refractive index layer. In addition to the low refractive index layer and the high refractive index layer, a medium refractive index layer having a refractive index of about 1.6 to 1.9 may be provided.

[0089] The thickness of each of the high refractive index layer and the low refractive index layer is about 5 nm to 200 nm, and preferably about 15 nm to 150 nm. The thickness of each layer may be designed so that the reflectance of visible light is small according to the refractive index and the layer structure.

[0090] The anti-reflection layer is preferably laminated on the hard coat layer via a primer layer. Examples of materials constituting the primer layer include metals such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, tungsten, aluminum, zirconium, and palladium; alloys of these metals; and oxides, fluorides, sulfides, or nitrides of these metals. Among these, the material of the primer layer is preferably an oxide, and silicon oxide is particularly preferred. The primer layer is preferably an inorganic oxide layer having a smaller amount of oxygen than the stoichiometric composition. Among inorganic oxides of non-stoichiometric composition, silicon oxide represented by the composition formula SiOx (0.5≦x<2) is preferred. The thickness of the primer layer is, for example, about 1 nm or more and 20 nm or less, and preferably 3 nm or more and 15 nm or less.

[0091] The method for forming the thin film constituting the anti-reflection layer is not particularly limited, and may be either a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, sputtering, and electron beam deposition are preferred because they can form a thin film with a uniform thickness. Among them, sputtering is preferred because it has excellent uniformity of film thickness and is easy to form a dense film. For example, the anti-reflection layer described in JP-A-2020-52221 can be suitably used. The entire disclosure of JP-A-2020-52221 is incorporated herein by reference.

[0092] EXAMPLES Hereinafter, the light-guiding member for a lighting device according to the embodiment of the present invention will be described in more detail by way of examples.

[0093] In the examples, light-guiding members 200AD_a and 220AD_a were fabricated having the cross-sectional structures shown in Fig. 12A and Fig. 13A. The light-guiding member 200AD_a shown in Fig. 12A substantially corresponds to the light-guiding member 200AD shown in Fig. 10, and the light-guiding member 220AD_a shown in Fig. 13A substantially corresponds to the light-guiding member 220AD shown in Fig. 11.

[0094] The light guide member 200AD_a shown in Fig. 12A has base material layers 30A and 30B and adhesive layers 52, 54, and 56 in addition to the light guide member 200AD shown in Fig. 10. In the light guide member 200AD_a, the first direction changing layer 60A in the light guide member 200AD is composed of the shaping film 62 and the adhesive layer 54 (or further the adhesive layer 52) shown in Fig. 14A and Fig. 14B. That is, by arranging the shaping film 62A so that the recess 64 of the shaping film 62 shown in Fig. 14B forms an internal space 64A by the adhesive layer 54, a structure substantially corresponding to the first direction changing layer 60A is obtained.

[0095] Similarly, the light guide member 200BD_a shown in FIG. 12B is obtained by arranging the shaping film 62B so that the recess 64 of the shaping film 62 shown in FIG. 14B forms an internal space 64B by the adhesive layer 54. The base layers 30A, 30B, and 30C play a role of supporting the first low refractive index layer 20A, the second low refractive index layer 20B, the first hard coat layer 40A, or the second hard coat layer 40B, for example. The positional relationship between the base layers 30A, 30B, and 30C and the first low refractive index layer 20A, the second low refractive index layer 20B, the first hard coat layer 40A, and the second hard coat layer 40B may be appropriately changed. For example, in the light guide member 200AD_a, the first low refractive index layer 20A is supported by the base layer 30A, while in the light guide member 200BD_a, the first low refractive index layer 20A is supported by the base layer 30B.

[0096] The light guide member 220AD_a shown in Fig. 13A has base material layers 30A, 30B, and 30C and adhesive layers 52, 54, 56, and 58 in addition to the light guide member 220AD shown in Fig. 11. In the light guide member 220AD_a, the first direction changing layer 60A in the light guide member 220AD is composed of the shaping film 62 and the adhesive layer 54 (or further the adhesive layer 52) shown in Fig. 14A and Fig. 14B. That is, by arranging the shaping film 62A so that the recess 64 of the shaping film 62 shown in Fig. 14B forms an internal space 64A by the adhesive layer 54, a structure substantially corresponding to the first direction changing layer 60A is obtained.

[0097] Also, as in the light-guiding member 220AD_b shown in Fig. 13B, the shaped film 62A may be disposed on the base material layer 30B so that the recesses 64 of the shaped film 62 shown in Fig. 14B form an internal space 64A by the adhesive layer 54, thereby obtaining a structure substantially corresponding to the first direction changing layer 60A. Similarly, the light-guiding member 220BD_a shown in Fig. 13C is obtained by disposing the shaped film 62B so that the recesses 64 of the shaped film 62 shown in Fig. 14B form an internal space 64B by the adhesive layer 54.

[0098] Here, the term "adhesive" is used to include pressure-sensitive adhesives (also called pressure sensitive adhesives). Specific examples of adhesives include rubber-based adhesives, acrylic-based adhesives, silicone-based adhesives, epoxy-based adhesives, cellulose-based adhesives, and polyester-based adhesives. These adhesives may be used alone or in combination of two or more.

[0099] If a porous material (e.g., a gel formed from a silicon compound) is used as the low refractive index layer, the strength is low and the material is brittle. Therefore, a base layer (e.g., an acrylic film) is used, and the low refractive index layers 20A and 20B and the low refractive index region 80a are formed on the base layer.

[0100] In order to mass-produce the light guide member by a roll-to-roll method or a roll-to-sheet method, a laminate laminated on a plurality of base layers is bonded with an adhesive layer. A structure corresponding to the first direction changing layer 60A (FIGS. 10 and 11) having a plurality of internal spaces 64A is formed by a shaping film 62 having recesses 64 and an adhesive layer 54.

[0101] The thickness of the base layers 30A, 30B, and 30C is, for example, independently from 1 μm to 1000 μm, preferably from 10 μm to 100 μm, and more preferably from 20 μm to 80 μm. The refractive index of the base layers 30A, 30B, and 30C is, for example, independently from 1.40 to 1.70, and more preferably from 1.43 to 1.65.

[0102] The thicknesses of the adhesive layers 52, 54, 56, 58 are each independently, for example, 0.1 μm to 100 μm, preferably 0.3 μm to 100 μm, and more preferably 0.5 μm to 50 μm. The refractive indexes of the adhesive layers 52, 54, 56, 58 are each independently, preferably 1.42 to 1.60, and more preferably 1.47 to 1.58. The refractive indexes of the adhesive layers 52, 54, 56, 58 are preferably close to the refractive index of the light guide layer 10 or the shaping film 62 to which they are in contact, and the absolute value of the difference in the refractive index is preferably 0.2 or less. EXAMPLES

[0103] The methods for measuring each characteristic are as follows.

[0104] [Refractive index] 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 that did not reflect on the back surface of the glass plate.

[0105] The sample was set in an ellipsometer (product name: VASE, manufactured by JA Woollam Japan), and the refractive index was measured under conditions of 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. Unless otherwise specified, the refractive index in this specification is based on this definition.

[0106] [Scratch resistance] The steel wool test (φ25mm) was performed with a load of 100g x 10 times, and the presence or absence of scratches was visually confirmed. When no scratches were visible, it was rated as ◯ (Good), and when scratches were visible, it was rated as × (NG).

[0107] [Anti-stain properties] When an oil-based marker (manufactured by Zebra: product name: Extra Fine Mackie) was applied to the light exit surface of the light guide member, if the ink was visually repelled, it was rated as ◯, and if the ink blended with the surface and was not repelled, it was rated as ×.

[0108] [Haze value] The sample was cut to a size of 50 mm×50 mm, and the haze value was measured using a haze meter (manufactured by Murakami Color Research Laboratory: product name HM-150).

[0109] [Visible light transmittance] The visible light transmittance of the sample was determined as the average value of the visible light transmittance at each wavelength when measured using a spectrophotometer at a measurement wavelength of 380 nm to 780 nm. Here, the visible light transmittance was also measured using the above-mentioned haze meter.

[0110] [Production Example 1] Manufacturing of textured film The unevenly shaped film was produced according to the method described in JP-A-2013-524288. Specifically, the surface of a polymethyl methacrylate (PMMA) film was coated with lacquer (Finecure RM-64 manufactured by Sanyo Chemical Industries, Ltd.), an optical pattern was embossed on the film surface containing the lacquer, and then the lacquer was cured to produce the desired unevenly shaped film. The total thickness of the unevenly shaped film was 130 μm, and the haze was 0.8%.

[0111] FIG. 14A shows a plan view of a portion of the produced unevenly shaped film as viewed from the uneven surface side. FIG. 14B shows a 14B-14B' cross-sectional view of the unevenly shaped film of FIG. 14A. A plurality of recesses having a length L of 80 μm, a width W of 14 μm, and a depth H of 10 μm, and a triangular cross section, were arranged in the X direction at intervals of width E (155 μm). Furthermore, such a pattern of recesses was arranged in the Y direction at intervals of width D (100 μm). The density of recesses on the surface of the unevenly shaped film was 3612 pieces / cm. 2 15, θa and θb were both 41°, and the occupied area ratio of the recesses when the film was viewed in plan from the uneven surface side was 4.05%.

[0112] [Production Example 2] Preparation of coating solution for forming low refractive index layer It was produced according to the description in International Publication No. 2019 / 026865. Specifically, the process is as follows.

[0113] (1) Gelation of silicon compounds 0.9 g of methyltrimethoxysilane (MTMS), a precursor of a gel-like silicon compound, was dissolved in 2.2 g of dimethyl sulfoxide (DMSO) to prepare mixed solution A. 0.5 g of 0.01 mol / L oxalic acid solution was added to this mixed solution A, and the mixture was stirred at room temperature for 30 minutes to hydrolyze MTMS, producing mixed solution B containing tris(hydroxy)methylsilane.

[0114] To 5.5 g of DMSO, 0.38 g of 28% by mass ammonia water and 0.2 g of pure water were added, and then the above mixed solution B was further added and stirred at room temperature for 15 minutes to gel tris(hydroxy)methylsilane, thereby obtaining mixed solution C containing a gel-like silicon compound.

[0115] (2) Aging treatment The mixed solution C containing the gel-like silicon compound prepared as above was incubated as it was at 40° C. for 20 hours for aging treatment.

[0116] (3) Crushing Next, the gel-like silicon compound aged as described above was crushed into granules of several mm to several cm in size using a spatula. Next, 40 g of isopropyl alcohol (IPA) was added to the mixed liquid C, and after light stirring, the mixture was left to stand at room temperature for 6 hours, and the solvent and catalyst in the gel were decanted. The same decantation process was performed three times to replace the solvent, and a mixed liquid D was obtained. Next, the gel-like silicon compound in the mixed liquid D was crushed (high-pressure media-less crushing). The crushing process (high-pressure media-less crushing) was performed using a homogenizer (manufactured by SMT Co., Ltd., product name "UH-50"), and 1.85 g of the gel-like compound and 1.15 g of IPA in the mixed liquid D were weighed into a 5 cc screw bottle, and crushed for 2 minutes under the conditions of 50 W and 20 kHz.

[0117] The gel-like silicon compound in the mixed solution D was pulverized by this pulverization process, and the mixed solution D' became a sol solution of the pulverized material. The volume average particle size indicating the particle size variation of the pulverized material contained in the mixed solution D' was confirmed to be 0.50 to 0.70 by using a dynamic light scattering nanotrack particle size analyzer (manufactured by Nikkiso Co., Ltd., UPA-EX150 type), and was found to be 0.50 to 0.70. Furthermore, 0.062 g of a 1.5 mass % concentration MEK (methyl ethyl ketone) solution of a photobase generator (Wako Pure Chemical Industries, Ltd.: product name WPBG266) and 0.036 g of a 5% concentration MEK solution of bis(trimethoxysilyl)ethane were added to 0.75 g of this sol solution (mixed solution C') to obtain a coating solution for forming a low refractive index layer (microporous particle-containing liquid).

[0118] [Production Example 3] Preparation of hard coat (HC) layer coating solution The manufacturing method was carried out with reference to the manufacturing method described in JP 2011-237789 A. Specifically, the manufacturing method is as follows.

[0119] To a resin solution (manufactured by DIC, product name "UNIDIC 17-806", solid content concentration 80%) in which an ultraviolet-curable resin monomer or oligomer mainly composed of urethane acrylate was dissolved in butyl acetate, 5 parts of a photopolymerization initiator (manufactured by BASF, product name "IRGACURE906") and 0.5 parts of a leveling agent (manufactured by DIC, product name "GRANDIC PC4100") were added per 100 parts of solid content in the solution. Then, butyl acetate was added to the solution so that the solid content concentration in the solution was 75%. Furthermore, cyclopentanone was added to the solution so that the solid content concentration in the solution was 50%. In this way, an HC layer coating liquid for forming an HC layer was prepared.

[0120] [Production Example 4] Formation of adhesive A layer (adhesive layer 54) An adhesive A layer was formed by the following procedure: The adhesive A layer can bond without filling recesses on the surface.

[0121] (1) Preparation of adhesive A solution In a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler, 95.0 parts by mass of n-butyl acrylate, 5.0 parts by mass of acrylic acid, and 0.2 parts by mass of 2,2'-azobisisobutyronitrile as a polymerization initiator were charged together with ethyl acetate so that the total monomer amount was 40.0% by mass. Nitrogen gas was introduced while gently stirring to replace the atmosphere with nitrogen for 1 hour, and the liquid temperature in the flask was kept at around 63°C to carry out a polymerization reaction for 6 hours. Ethyl acetate was then added so that the solid content was 40% by mass, and an acrylic polymer was obtained. 6.0 parts by mass of 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (trade name "TETRAD-C", manufactured by Mitsubishi Gas Chemical Co., Ltd.) was added as a crosslinking agent to the obtained acrylic polymer solution relative to 100 parts by mass of the solid content of the polymer to prepare an adhesive A solution.

[0122] (2) Formation of adhesive A layer The adhesive A solution was applied to one side of a 38 μm polyethylene terephthalate (PET) film (product name "MRF38", manufactured by Mitsubishi Chemical Corporation) that had been subjected to a silicone release treatment so that the adhesive layer would be 1 μm thick after drying, and then dried at 150° C. for 3 minutes to form an adhesive A layer. The refractive index was 1.47.

[0123] [Production Example 5] Formation of Adhesive B Layer (Adhesive Layers 52, 56, 58) An adhesive layer B was formed with reference to the method described in JP 2018-136401 A. Specifically, the method is as follows.

[0124] (1) Preparation of acrylic polymer A monomer mixture containing 82 parts of butyl acrylate, 15 parts of benzyl acrylate, and 3 parts of 4-hydroxybutyl acrylate was charged into a four-neck flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler. Furthermore, 0.1 parts of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with ethyl acetate for 100 parts of the monomer mixture (solid content), and nitrogen gas was introduced while gently stirring to replace the atmosphere with nitrogen. The liquid temperature in the flask was kept at about 60°C and a polymerization reaction was carried out for 7 hours. Ethyl acetate was then added to the resulting reaction liquid to prepare a solution of an acrylic polymer with a mass average molecular weight of 1,000,000, with a solid content concentration of 30%.

[0125] (2) Preparation of adhesive B solution 0.002 parts of lithium bis(trifluoromethanesulfonyl)imide (manufactured by Nippon Carlit Co., Ltd.) was mixed with 100 parts of the solid content of the acrylic polymer solution obtained above, and further 0.1 parts of trimethylolpropane xylylene diisocyanate (manufactured by Mitsui Chemicals, Inc.: Takenate D110N), 0.3 parts of dibenzoyl peroxide, 0.075 parts of γ-glycidoxypropyl methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-403), and 0.5 parts of Kaneka Corporation's Silyl SAT10 (number average molecular weight 4000) were mixed to prepare adhesive B solution.

[0126] (3) Formation of adhesive layer B The adhesive B solution obtained above was uniformly applied with an applicator to the surface of a release substrate (Mitsubishi Plastics, Inc. MRF38CK) made of a PET film treated with a silicone-based release agent, and dried for 2 minutes in an air-circulating thermostatic oven at 155°C to form an adhesive B layer. The adhesive B layer had a refractive index of 1.47 and a thickness of 10 μm.

[0127] Example 1

[0128] (1) Fabrication of light-guiding components The light-guiding member 200AD_a shown in FIG. 12A was produced.

[0129] The adhesive A layer formed in Production Example 4 was laminated to the uneven surface of the unevenly shaped film of Production Example 1 using a hand roller to obtain a laminate of unevenly shaped film / adhesive A layer / PET film. Next, the PET film of the laminate was peeled off, and the laminate was laminated to an acrylic plate (manufactured by Mitsubishi Chemical Corporation: product name Acrylite) having a thickness of 5 mm, a width of 120 mm, and a length of 700 mm using a hand roller to obtain a laminate of unevenly shaped film / adhesive A layer / light guide layer.

[0130] The HC layer coating liquid prepared in Production Example 3 was applied with a wire bar to one side of an acrylic film (base layer) having a refractive index of 1.51 and a thickness of 40 μm, and then dried at 80° C. for 1 minute. After that, the coating liquid was exposed to light with a wavelength of 360 nm at 300 mJ / cm 2 . 2 The HC layer was irradiated with UV light at a light irradiation dose (energy) of 1.52 to obtain an HC layer / acrylic film laminate. The thickness of the HC layer was 5 μm. The refractive index of the HC layer was 1.52.

[0131] The low refractive index layer coating liquid prepared in Production Example 2 was applied to the acrylic film surface of the HC layer / acrylic film laminate, and dried at a temperature of 100°C for 1 minute. The dried coating layer was then irradiated with light of 360 nm wavelength at 300 mJ / cm. 2 A laminate of an HC layer / acrylic film / low refractive index layer was obtained. At this time, the refractive index of the low refractive index layer was 1.15 (thickness 1 μm).

[0132] The adhesive B layer prepared in Production Example 5 was attached to the low refractive index layer surface of the HC layer / acrylic film / low refractive index layer laminate prepared as above, to obtain a laminate of HC layer / acrylic film / low refractive index layer / adhesive B layer / PET film. Two of these were prepared. The PET film of each laminate was peeled off and attached to both sides of the unevenness-imparting film / adhesive A layer / light-guiding layer laminate prepared above, to produce the desired light-guiding member.

[0133] (2) Preparation of lighting device An LED line light source (manufactured by Nichia Corporation, 0.4 mm thick, side view mounted) was installed on the side of the light guide layer of the light guide member to fabricate a lighting device. Note that the lighting test was performed at 12 V.

[0134] Example 2 (1) Fabrication of light-guiding components The light-guiding member 220AD_a shown in FIG. 13A was produced.

[0135] A mask plate with holes in a predetermined area was placed on one side of an acrylic film with a refractive index of 1.51 and a thickness of 40 μm, and the coating liquid for forming a low refractive index layer of Production Example 2 was applied. At this time, a mask plate was used that would make the low refractive index regions 80a in the formed optical coupling layer 80 dense (almost all low refractive index regions 80a are present) on the side closer to the light source and sparse (many regions without low refractive index regions 80a) as they moved away from the light source. The coating layer after drying was irradiated with 300 mJ / cm using light with a wavelength of 360 nm. 2 The low refractive index region 80a was formed by irradiating the low refractive index region 80a with UV at a light irradiation dose (energy) of 1000 nm and removing the mask plate. A plan view of the formed low refractive index region 80a is shown in FIG. 16. The dots in the figure indicate the areas where the low refractive index forming coating liquid was applied (the pattern layer portion also exists in the area surrounded by the dashed line, but is omitted in the figure). The size of the dots is, for example, 1 μm or more and 1000 μm or less. By providing such an optical coupling layer 80, the occupancy rate of the recesses (internal spaces 14A, 64A) of the shaping film can be made uniform over the entire surface.

[0136] The adhesive A solution was applied to the pattern layer to obtain a laminate of acrylic film / pattern layer of low refractive index material / adhesive A layer. Furthermore, the uneven surface of the unevenness-imparting film was attached to the adhesive A layer of the laminate to obtain a laminate of acrylic film / pattern layer of low refractive index material / adhesive A layer / unevenness-imparting film.

[0137] The adhesive B layer of the HC layer / acrylic film / low refractive index layer / adhesive B layer laminate produced in Example 1 was bonded to the unevenness-imparting film surface of the acrylic film / patterned layer of low refractive index material / adhesive A layer / unevenness-imparting film laminate to obtain a laminate of HC layer / acrylic film / low refractive index layer / adhesive B layer / unevenness-imparting film / adhesive A layer / patterned layer of low refractive index material / acrylic film.

[0138] The laminate and the light guide layer were then bonded together via the adhesive B layer so that the light guide layer and the acrylic film faced each other, to obtain a laminate of HC layer / acrylic film / low refractive index layer / adhesive B layer / patterned film / adhesive A layer / low refractive index material pattern layer / acrylic film / adhesive B layer / light guide layer. The adhesive B layer of the HC layer / acrylic film / low refractive index layer / adhesive B layer laminate produced in Example 1 was bonded to the light guide layer surface of the laminate, to produce the desired light guide member.

[0139] (2) Preparation of lighting device An illumination device was produced in the same manner as in Example 1(2).

[0140] Comparative Example 1 (1) Fabrication of light-guiding components FIG. 17 shows a schematic diagram of a light guide member 910A of Comparative Example 1.

[0141] The adhesive B layer of Production Example 5 was attached to the surface opposite to the uneven surface of the unevenness-imparting film of Production Example 1. Thereafter, the PET film of the adhesive B layer was peeled off, and the adhesive B layer was attached to the light guide layer to prepare the intended light guide member.

[0142] (2) Preparation of lighting device An illumination device was produced in the same manner as in Example 1(2).

[0143] Comparative Example 2 (1) Fabrication of light-guiding components FIG. 18 shows a schematic diagram of a light-guiding member 920A of Comparative Example 2.

[0144] The desired light-guiding member was produced by bonding the surface of the unevenness-imparting film of the unevenness-imparting film / adhesive A layer / light-guiding layer laminate produced in Example 1 to the adhesive B layer of the HC layer / acrylic film / adhesive B layer laminate.

[0145] (2) Preparation of lighting device An illumination device was produced in the same manner as in Example 1(2).

[0146] Comparative Example 3 A light guide member and a lighting device were produced in the same manner as in Example 1, except that the unevenness-imparting film disclosed in FIG. 10(B) of Patent Document 2 was used instead of the unevenness-imparting film used in Example 1. FIG. 19A shows a plan view of a part of the unevenness-imparting film 92 used, seen from the uneven surface side. FIG. 19B shows a cross-sectional view taken along 19B-19B' in FIG. 19A. When the unevenness-imparting film 92 is seen from the uneven surface side, the ratio of the area of ​​the recesses 94 to the total area of ​​the unevenness-imparting film 92 was 61%.

[0147] [Check for light leaks] Before and after the scratch resistance test and before and after the antifouling test, light leakage around scratches and stains was visually confirmed for the lighting devices of Examples 1 and 2 and Comparative Examples 1, 2, and 3. The cases where there was no light leakage were evaluated as ◯, and the cases where there was light leakage were evaluated as ×.

[0148] [Checking light uniformity] A 10 mm wide, 120 mm long black tape (vinyl tape manufactured by Nitto Denko Corporation) was attached to the center of the light exit surface of the light guide member, and the luminance was measured at a position 30 mm from the light source and at a position 670 mm away from the light source. The luminance was measured using a two-dimensional luminance meter (manufactured by TOPCOM Corporation: product name SR-5000HS). The luminance at a position 30 mm from the light source (near end) was taken as 100%, and the luminance ratio at a position 670 mm away from the light source (far end) was measured. The results are shown in Table 1.

[0149] [Table 1]

[0150] In Example 1, since low refractive index layers are present on both sides of the light guide layer, it is understood that the light is guided without loss without being affected by dirt. Furthermore, it is understood that the light is propagated without loss at the entrance and exit even if a light absorbing medium is present in the middle of the waveguiding.

[0151] In addition, it can be seen that in Example 2, the low refractive index layer is patterned, thereby enabling light to be extracted more uniformly at the inlet and outlet.

[0152] [Building materials] The above-mentioned sheet-like (or film-like) transparent lighting device is used as a building material. The lighting device itself can be used as a building material, or it can be used as a part of a building material. Building materials include exterior and interior materials. For example, they can be used as window materials, wall materials, partitions, ceiling (skylight) materials, staircase materials, handrail materials, and floor materials. In addition, they can be used as lighting devices for streets, crime prevention, emergencies, gardens, pools and ponds (underwater), inside warehouses, inside factories, and under the eaves (outdoors). In all cases, they are used as transparent plates when not in use.

[0153] Also, a function to change the color of the illumination and / or a function to change the illuminated area can be added. The color or illuminated area may be changed over time. The type (color), number, and arrangement of the LEDs used as the light source may vary. Of course, the shape, size, and thickness of the light guide layer may also vary.

[0154] Furthermore, by tiling a plurality of sheet-type lighting devices, a larger lighting device can be used as a larger architectural component. Also, a plurality of sheet-type lighting devices can be stacked for use.

[0155] By using the lighting device according to the embodiment of the present invention, architectural components that are rich in design and entertainment value can be provided. [Industrial Applicability]

[0156] According to an embodiment of the present invention, a lighting device and a light-guiding member for a lighting device having a higher transmittance and a smaller haze value than conventional lighting devices are provided, and lighting with high design value or entertainment value is provided. According to an embodiment of the present invention, a building component capable of providing lighting with high design value or entertainment value is provided. [Explanation of symbols]

[0157] 10, 10A, 10B: Light guide layer 14, 14A, 14B, 64A, 64B: Internal space 20A, 20B: Low refractive index layer 30A, 30B, 30C: Base material layer 40A, 40B: Hard coat layer 52, 54, 56, 58 adhesive layer 100A, 100B, 200A, 200B: Light guide member 100A_L, 200A_L: Lighting device

Claims

1. A light guide layer having a first main surface, a second main surface opposite to the first main surface, and a light guide layer for receiving light from a light source. a light guide layer having a light receiving side for receiving the guided light; The light guide layer has a refractive index n ＧＰ Refraction smaller than rate n Ｌ1 A first low refractive index layer having A part of the light propagating in the light guide layer is guided to at least the first low refractive index layer side or the first low refractive index layer side. A light distribution control structure that can be directed to the opposite side to the refractive index layer; having A visible light transmittance of 80% or more and a haze value of less than 5%, the light distribution control structure is formed in a first direction conversion layer provided on the second main surface side of the light guide layer, and has a plurality of internal spaces that form interfaces that direct light toward the first low refractive index layer side or an opposite side to the first low refractive index layer side by total internal reflection; the plurality of internal spaces are discretely arranged in a light guide direction of the light guide layer and in a direction perpendicular to the light guide direction, and when the light guide layer is viewed in a plan view from a direction normal to the first main surface, a ratio of an area of ​​the plurality of internal spaces to an area of ​​the light guide layer is less than 10%.

2. The light-guiding member for a lighting device according to claim 1 , wherein the light distribution control structure directs at least a part of light propagating in the light-guiding layer toward the first low refractive index layer.

3. The light-guiding member for an illumination device according to claim 1 , wherein the light distribution control structure directs at least a part of light propagating within the light-guiding layer toward an opposite side to a side of the first low refractive index layer.

4. 4 . The light-guiding member for an illumination device according to claim 1 , further comprising a first hard coat layer disposed on the side of the first low refractive index layer opposite to the light-guiding layer and having a hardness of pencil hardness H or more.

5. 5. The light-guiding member for an illumination device according to claim 4, further comprising a first base material layer on an opposite side of the first low refractive index layer to the light-guiding layer, and the first hard coat layer is formed on the opposite side of the first base material layer to the first low refractive index layer.

6. A first optical coupling layer is provided between the light guiding layer and the first direction changing layer, The first optical coupling layer has a refractive index n ＧＰ A refractive index n smaller than Ｃ1 Complex with The light-guiding member for an illumination device according to claim 1 , further comprising a first low refractive index region having a first refractive index of 1 to 5.

7. The light guide layer has a refractive index n ＧＰ A refractive index n smaller than Ｌ２ The light-guiding member for an illumination device according to claim 1 , further comprising a second low refractive index layer having a refractive index of

8. The second low refractive index layer is disposed on the opposite side of the light guide layer, and the hardness H ＧＰ Hardness H higher than Ｈ２ The light-guiding member for a lighting device according to claim 7 , further comprising a second hard coat layer having the following formula:

9. 9. The light-guiding member for a lighting device according to claim 8, further comprising a second base material layer on an opposite side of the second low refractive index layer to the light-guiding layer, and the second hard coat layer is formed on the opposite side of the second base material layer to the second low refractive index layer.

10. The light-guiding member for a lighting device according to claim 8 or 9, which indirectly relies on claim 4, wherein a haze value of the first hard coat layer is greater than a haze value of the second hard coat layer.

11. The light-guiding member for a lighting device according to claim 1 , further comprising an antifouling layer having water repellency and / or oil repellency as an outermost layer on the first main surface side or the second main surface side.

12. The light-guiding member for a lighting device according to claim 11 , further comprising an antireflection layer provided on the light-guiding layer side of the antifouling layer.

13. A light-guiding member for a lighting device according to claim 1 , a light source that emits light toward the light receiving side surface; A lighting device comprising:

14. A building member comprising the light-guiding member for a lighting device according to claim 1 .

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