Light-emitting device and light guide member

Abstract

This light guide member comprises a first light guide layer and a first light distribution control structure. The first light guide layer has a first main surface, a second main surface that is on the opposite side from the first main surface, and a first light receiving part that receives first light which has been emitted from a light source. The first light distribution control structure can direct, toward at least the first main surface side or the second main surface side, some of the first light which propagates inside the first light guide layer. In a plan view of the light guide member from the direction normal to the first main surface, a first region in which the first light distribution control structure is present and a second region in which the first light distribution control structure is not present are disposed so as to define a first pattern that represents a first two-dimensional code. Visible light transmittance of the light guide member is not less than 70%, and the haze value is not more than 10%.

Description

Light Emitting Device and Light Guiding Member

[0001] The present invention relates to a light emitting device and a light guiding member.

[0002] In recent years, the use of next-generation semiconductor lighting (Solid State Lighting: SSL) represented by LED lighting has been progressing. A configuration including a light source such as an LED and a light guide plate is widely used in lighting devices.

[0003] There is a need for a lighting device (which may also be referred to as a "light emitting device") that is transparent when turned off and can emit light in character or pattern shapes when turned on. As a method for realizing such a light emitting device, a technique is known in which a structure for extracting light (for example, fine prisms or dot patterns) is formed only on a part of a light guide plate by laser engraving, an inkjet method, or the like. Patent Document 1 discloses a light-spot display in which a group of reflective dots is formed in characters or graphic shapes on a light guide plate as the aforementioned light emitting device.

[0004] Japanese Unexamined Patent Application Publication No. 2004-069729

[0005] In conventional light emitting devices, there is a trade-off between the amount of light emitted from the light guide plate and the transparency of the light guide plate in the design of the pattern density of the structure for extracting light, and it is difficult to increase transparency when attempting to secure a sufficient amount of light. Furthermore, it is difficult to apply the structures for extracting light used in conventional light emitting devices to high-definition patterns such as two-dimensional codes.

[0006] An object of an embodiment of the present invention is to provide a light emitting device that has high transparency and can emit a pattern representing a two-dimensional code, and a light guiding member that is suitably used in such a light emitting device.

[0007] According to an embodiment of the present invention, the solutions described in the following items are provided.

[0008] [Item 1] A light guide member having a first light guide layer having a first main surface, a second main surface opposite to the first main surface, and a first light receiving portion that receives first light emitted from a light source, and a first light distribution control structure that can direct at least a portion of the first light propagating within the first light guide layer toward the first main surface side or the second main surface side, wherein when viewed from the normal direction of the first main surface, a first region where the first light distribution control structure exists and a second region where the first light distribution control structure does not exist are arranged to define a first pattern indicating a first two-dimensional code, and the visible light transmittance is 70% or more and the haze value is 10% or less. [Item 2] The light guide member according to Item 1, wherein the first light distribution control structure has a plurality of first internal spaces that form an interface that directs light toward the first main surface side or the second main surface side by internal total internal reflection. [Item 3] The light guide member according to Item 2, wherein the plurality of first internal spaces of the first light distribution control structure are formed within the first light guide layer. [Item 4] The light guide member according to Item 2, wherein the first light distribution control structure is formed in a first direction conversion layer provided on the first main surface side or the second main surface side of the first light guide layer. [Item 5] A light-emitting device comprising a light guide member according to any one of Items 1 to 4 and a first light source that emits the first light toward the first light receiving section, wherein the first light emitted by the first light source includes invisible light. [Item 6] The light-emitting device according to Item 5, wherein the first light emitted by the first light source includes infrared light. [Item 7] The light guide member according to any one of items 1 to 4, further comprising: a second conductive layer disposed on the first main surface side or the second main surface side of the first light guide layer, having a third main surface, a fourth main surface opposite to the third main surface, and a second light receiving portion for receiving second light emitted from a light source; and a second light distribution control structure that can direct at least a portion of the second light propagating within the second light guide layer toward at least the third main surface side or the fourth main surface side, wherein, when viewed in plan from the direction normal to the third main surface, the third region where the second light distribution control structure exists and the fourth region where the second light distribution control structure does not exist are arranged to define a second pattern showing a second two-dimensional code different from the first two-dimensional code.[Item 8] The light guide member according to Item 7, wherein the second light distribution control structure has a plurality of second internal spaces that form an interface that directs light toward the third main surface side or the fourth main surface side by internal total internal reflection. [Item 9] The light guide member according to Item 8, wherein the plurality of second internal spaces of the second light distribution control structure are formed within the second light guide layer. [Item 10] The light guide member according to Item 8, wherein the second light distribution control structure is formed in a second direction conversion layer provided on the third main surface side or the fourth main surface side of the second light guide layer. [Item 11] The light guide member according to any one of items 1 to 4, further comprising a second light distribution control structure capable of directing at least a portion of the light propagating within the first light guide layer toward at least the first main surface side or the second main surface side, wherein, when viewed from the normal direction of the first main surface, the third region where the second light distribution control structure exists and the fourth region where the second light distribution control structure does not exist are arranged to define a second pattern showing a second two-dimensional code different from the first two-dimensional code. [Item 12] The light guide member according to item 11, wherein the second light distribution control structure has a plurality of second internal spaces that form an interface for directing light toward the first main surface side or the second main surface side by internal total internal reflection. [Item 13] The light guide member according to item 12, wherein the plurality of second internal spaces of the second light distribution control structure are formed within the first light guide layer. [Item 14] The light guide member according to Item 12, wherein the second light distribution control structure is formed on a second direction conversion layer provided on the first main surface side or the second main surface side of the first light guide layer. [Item 15] A light-emitting device comprising the light guide member according to any one of Items 7 to 10, a first light source that emits the first light toward the first light receiving section, and a second light source that emits the second light toward the second light receiving section. [Item 16] The light-emitting device according to Item 15, wherein the first light includes invisible light, and the second light includes visible light. [Item 17] A light-emitting device comprising the light guide member according to any one of Items 11 to 14, a first light source that emits the first light including invisible light toward the first light receiving section, and a second light source that emits the second light including visible light toward the first light receiving section.

[0009] According to embodiments of the present invention, there is a light-emitting device that has high transparency and can emit a pattern showing a two-dimensional code, and a light guide member suitably used in such a light-emitting device.

[0010] This is a schematic cross-sectional view of a light-emitting device 200A according to an embodiment of the present invention. This is a plan view showing an example of a first region R1 and a second region R2 having of the light-emitting device 200A. This is a schematic plan view of a first light guide member 110A having of the light-emitting device 200A. This is a schematic cross-sectional view of a first internal space 11A that the first light guide member 110A may have. This is a schematic plan view of the first internal space 11A. This is a schematic plan view showing a variation of the first internal space 11A. This is a schematic cross-sectional view of a light-emitting device 200A1 according to a modified embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200A2 according to a modified embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200B according to another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200B1 according to a modified embodiment of another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200B2 according to a modified embodiment of another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200C according to yet another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200D according to yet another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200D1 according to a modified example of yet another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200E according to yet another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200E1 according to a modified example of yet another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200E2 according to a modified example of yet another embodiment of the present invention. This is a schematic cross-sectional view of a light-emitting device 200E3 according to a modified example of yet another embodiment of the present invention.

[0011] The light-emitting device and light-guiding member according to embodiments of the present invention will be described below with reference to the drawings. The light-emitting device and light-guiding member according to embodiments of the present invention are not limited to those exemplified below. In the following drawings, components having substantially the same function are indicated by common reference numerals, and their descriptions may be omitted. The drawings show a Cartesian coordinate system having mutually orthogonal x, y, and z axes. The direction of the arrow on the x axis is referred to as the +x direction, the opposite direction as the -x direction, and when the ±x directions are not distinguished, they are simply referred to as the x direction. The same applies to the ±y and ±z directions.

[0012] (Embodiment 1) The light-emitting device (illumination device) 200A according to this embodiment will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view showing the light-emitting device 200A.

[0013] As shown in Figure 1, the light-emitting device 200A includes a light guide member 100A, a first light source LS1, and a second light source LS2. The light guide member 100A includes a first light guide member 110A and a second light guide member 110B.

[0014] The light guide member 100A has opposing first and second main surfaces. In this example, the light-emitting device 200A is configured to emit visible light and invisible light towards the first main surface side of the light guide member 100A (in the -z direction in the figure). However, the light-emitting device according to the embodiment of the present invention is not limited to this, and may be configured to emit visible light and / or invisible light towards the second main surface side of the light guide member (in the +z direction).

[0015] The first light source LS1 emits first light. The first light is invisible light. Invisible light may include, for example, ultraviolet light, near-ultraviolet light, near-infrared light, infrared light, and radio waves. The first light includes, for example, infrared light.

[0016] The second light source LS2 emits a second light. This second light is visible light. Here, visible light is defined as light with a wavelength between 380 nm and 780 nm.

[0017] The first light source LS1 and the second light source LS2 are, for example, LED devices. Multiple LED devices may be used as the first light source LS1 or the second light source LS2. The multiple LED devices are arranged, for example, in the x direction.

[0018] The first light guide member 110A receives the first light emitted from the first light source LS1, propagates the light in the +y direction, and emits the light in the -z direction. The first light guide member 110A includes a first light guide layer 10A and a first light distribution control structure that can direct at least a portion of the first light propagating within the first light guide layer 10A toward the first main surface 10Am.

[0019] The first light guide layer 10A has a first main surface 10Am, a second main surface 10An opposite to the first main surface 10Am, and a first light receiving portion that receives first light emitted from the first light source LS1. In the illustrated example, the first light receiving portion of the first light guide layer 10A is the side surface (light receiving side surface) 10As1 of the first light guide layer 10A on the side facing the first light source LS1. The first light receiving portion of the first light guide layer 10A may be a part of the first main surface 10Am or the second main surface 10An (for example, the end of the first main surface 10Am or the second main surface 10An).

[0020] In the illustrated example, the direction in which the first light propagates within the first light guide layer 10A is the +y direction, but it may also be the -y direction. In that case, the first light receiving portion of the first light guide layer 10A may be the side surface 10As2 facing the side surface 10As1.

[0021] In this example, the first light distribution control structure is formed within the first light guide layer 10A. The first light distribution control structure illustrated here has a plurality of first internal spaces 11A having an interface (in this example, the first forward inclined surface ISa1) that directs light toward the first main surface 10Am by internal total internal reflection (TIR). In this example, a plurality of first internal spaces 11A are formed within the first light guide layer 10A. The "forward" in "forward inclined surface" of the internal space means that it is located on the light-receiving side (close to the light-receiving side) among the inclined sides of the internal space. The inclined surface of the internal space that is located on the opposite side from the light-receiving side (far from the light-receiving side) is called the "rear inclined surface". The first internal space 11A has the first forward inclined surface ISa1 as the forward inclined surface and the first rear inclined surface ISb1 as the rear inclined surface. Light distribution control structures having multiple internal spaces (air cavities) are described, for example, in International Publication Nos. 2019 / 182091, 2019 / 146628, 2011 / 124765, and 2019 / 087118. All of the disclosures in these four international publications are incorporated herein by reference. These disclosures may be applied to the first and second internal spaces of the light guide members of embodiments of the present invention.

[0022] When viewed from a plane from the normal direction of the first main surface 10Am, a first region R1 in which the first light distribution control structure exists and a second region R2 in which the first light distribution control structure does not exist are arranged to define a first pattern that indicates a first two-dimensional code. In this example, the first region R1 is a region of the first light guide layer 10A in which a plurality of first internal spaces 11A are formed, and the second region R2 is a region in which a plurality of first internal spaces 11A are not formed. The two-dimensional code may be a QR code (registered trademark), a barcode, an AR (Augmented Reality) marker such as an ArUco marker.

[0023] Figure 2 shows an example of the arrangement of the first region R1 and the second region R2. Figure 2 shows the state where the first light source LS1 is ON and the second light source LS2 is OFF. The first region R1, where the first light distribution control structure exists, is the region (light-emitting region) from which the first light is emitted when the first light source LS1 is ON, and the second region R2, where the first light distribution control structure does not exist, is the region (non-light-emitting region) from which the first light is substantially not emitted when the first light source LS1 is ON.

[0024] The second light guide member 110B receives the second light emitted from the second light source LS2, propagates the light in the +y direction, and emits the light in the -z direction. The second light guide member 110B includes a second light guide layer 10B and a second light distribution control structure that can direct at least a portion of the second light propagating within the second light guide layer 10B toward the third main surface 10Bm.

[0025] The second light guide layer 10B is positioned on the first main surface 10Am side of the first light guide layer 10A. The second light guide layer 10B has a third main surface 10Bm, a fourth main surface 10Bn opposite to the third main surface 10Bm, and a second light receiving section that receives the second light emitted from the second light source LS2. In the illustrated example, the second light receiving section of the second light guide layer 10B is the side surface (light receiving side surface) 10Bs1 of the second light guide layer 10B on the second light source LS2 side. The second light receiving section of the second light guide layer 10B may also be a part of the third main surface 10Bm or the fourth main surface 10Bn (for example, the end of the third main surface 10Bm or the fourth main surface 10Bn).

[0026] In the illustrated example, the direction in which the second light propagates within the second light guide layer 10B is the +y direction, but it may also be the -y direction. In that case, the second light receiving portion of the second light guide layer 10B may be the side surface 10Bs2 facing the side surface 10Bs1.

[0027] In this example, the second light distribution control structure is formed within the second light guide layer 10B. The second light distribution control structure illustrated here has a plurality of second internal spaces 11B having an interface (in this example, a second forward inclined surface ISa2) that directs light toward the third main surface 10Bm side by internal total internal reflection (TIR). In this example, a plurality of second internal spaces 11B are formed within the second light guide layer 10B. The second internal space 11B has a second forward inclined surface ISa2 as a forward inclined surface and a second backward inclined surface ISb2 as a backward inclined surface.

[0028] When viewed from the normal direction of the third main surface 10Bm, the third region R3 where the second light distribution control structure exists and the fourth region R4 where the second light distribution control structure does not exist are arranged to define a second pattern that defines a second two-dimensional code different from the first two-dimensional code. In this example, the third region R3 is a region of the second light guide layer 10B where a plurality of second internal spaces 11B are formed, and the fourth region R4 is a region where a plurality of second internal spaces 11B are not formed. An example of the second pattern is the same as an example of the first pattern. The third region R3 where the second light distribution control structure exists is a region (light-emitting region) where the second light is emitted when the second light source LS2 is ON, and the fourth region R4 where the second light distribution control structure does not exist is a region (non-light-emitting region) where the second light is substantially not emitted when the second light source LS2 is ON.

[0029] The visible light transmittance of the light guide member 100A is 70% or more. Therefore, the light guide member 110A has high transparency (visible light transmittance). As a result, the space behind the second main surface can be seen through the space on the first main surface side of the light guide member 110A, and the space on the second main surface side can be seen. Here, visible light is defined as light with a wavelength of 380 nm or more and 780 nm or less. The visible light transmittance of the light guide member 100A is preferably, for example, 80% or more, 85% or more, or 90% or more. The haze value of the light guide member 100A is 10% or less. The haze value of the light guide member 100A is preferably, for example, 5% or less, 3% or less, 1% or less, or 0.5% or less. The visible light transmittance and haze value can be measured, for example, using a haze meter (manufactured by Murakami Color Technology Laboratory: product name HM-150).

[0030] In the light-emitting device 200A, the first light distribution control structure is arranged to define a first pattern, and the second light distribution control structure is arranged to define a second pattern. Therefore, the first pattern can be emitted by the first light (invisible light), and the second pattern can be emitted by the second light (visible light). The light-emitting device 200A can emit patterns that represent different two-dimensional codes in visible light and invisible light, while achieving high transparency.

[0031] The first pattern, generated by invisible light, can be detected by an invisible light detection device (for example, an infrared sensor or infrared camera if the first light includes infrared light), but it is not visible to the observer of the light-emitting device 200A. Therefore, the first pattern can be used, for example, as a pattern representing a two-dimensional code used to transmit information that should not be disclosed to an unspecified number of people or confidential information. The first pattern can also be used in cases where information is transmitted using a two-dimensional code that does not need to be visible to the observer of the light-emitting device 200A, or a two-dimensional code whose design may be impaired if it is visible. On the other hand, the second pattern, generated by visible light, is visible to the observer of the light-emitting device 200A, so information can be transmitted to the observer by the two-dimensional code represented by the second pattern. The second pattern, generated by visible light, may of course be detected by a visible light detection device (for example, a visible light camera).

[0032] The invisible light detection device and the visible light detection device may be arranged on the first main surface side of the light guide member 100A (for example, on the third main surface 10Bm side of the second light guide layer 10B). If the first light distribution control structure and / or the second light distribution control structure are configured to emit light in the +z direction, the invisible light detection device and / or the visible light detection device may be arranged on the second main surface side of the light guide member 100A.

[0033] In the light guide member 100A, a first light distribution control structure defining a first pattern is provided, thereby enabling high directivity to one side. Therefore, the controllability of the direction in which information is transmitted by the emission of the first pattern representing the first two-dimensional code can be enhanced. Similarly, in the light guide member 100A, a second light distribution control structure defining a second pattern is provided, thereby enabling high directivity to one side. Therefore, the controllability of the direction in which information is transmitted by the emission of the second pattern representing the second two-dimensional code can be enhanced.

[0034] In the light-emitting device 200A, the light guide member 100A has a first light distribution control structure having a plurality of first internal spaces 11A and a second light distribution control structure having a plurality of second internal spaces 11B. Since these light distribution control structures utilize internal total internal reflection, high transparency (visible light transmittance) of the light guide member 100A can be achieved.

[0035] In the light-emitting device 200A, a first pattern representing a first two-dimensional code is defined depending on the presence or absence of a first light distribution control structure having a plurality of first internal spaces 11A, so that light can be emitted in the first pattern. Similarly, in the light-emitting device 200A, a second pattern representing a second two-dimensional code is defined depending on the presence or absence of a second light distribution control structure having a plurality of second internal spaces 11B, so that light can be emitted in the second pattern. A light distribution control structure having internal spaces is suitably used for two-dimensional codes that require high-definition display (presentation).

[0036] The first pattern of light emission using the first light and the second pattern of light emission using the second light may occur simultaneously, or they may be configured to occur only one at a time. For example, a control device that controls the first light source LS1 and the second light source LS2 may control the first light source LS1 and the second light source LS2 so that they can be turned on simultaneously, or it may control the first light source LS1 and the second light source LS2 so that only one of them, the first light source LS1 or the second light source LS2, is turned on.

[0037] The first light guide member 110A and the second light guide member 110B may each independently have a visible light transmittance of, for example, 70% or more, preferably 80% or more, 85% or more, or 90% or more. Furthermore, the first light guide member 110A and the second light guide member 110B may each independently have a haze value of, for example, 10% or less, preferably 5% or less, 3% or less, 1% or less, or 0.5% or less.

[0038] In this example, the first light guide member 110A has a first light distribution control structure that has multiple internal spaces 11A (i.e., utilizes internal total internal reflection), so high transparency (visible light transmittance) can be achieved. Similarly, the second light guide member 110B has a second light distribution control structure that has multiple internal spaces 11B (i.e., utilizes internal total internal reflection), so high transparency (visible light transmittance) can be achieved.

[0039] In this example, the second main surface 10An of the first light guide layer 10A constitutes the first main surface of the light guide member 100A, and the third main surface 10Bm of the second light guide layer 10B constitutes the second main surface of the light guide member 100A. The fourth main surface 10Bn of the second light guide layer 10B is positioned to face the first main surface 10Am of the first light guide layer 10A, for example, via an air layer. The fourth main surface 10Bn of the second light guide layer 10B and the first main surface 10Am of the first light guide layer 10A may be bonded together via, for example, an adhesive layer. As the adhesive layer, a low refractive index layer having a lower refractive index than either the first light guide layer 10A or the second light guide layer 10B may be used, or a low refractive index layer may be arranged separately from the adhesive layer. In the latter case, for example, a low refractive index layer having a lower refractive index than either the first light guide layer 10A or the second light guide layer 10B is placed between the first light guide layer 10A and the second light guide layer 10B, and the first light guide layer 10A, the low refractive index layer, and the second light guide layer 10B are bonded together via an adhesive layer.

[0040] In this example, the second light guide layer 10B is positioned on the first main surface 10Am side of the first light guide layer 10A, but it is not limited to this, and the second light guide layer 10B may be positioned on the second main surface 10An side of the first light guide layer 10A.

[0041] In this example, a first light distribution control structure is formed in the first light guide layer 10A so as to define a first pattern, and a second light distribution control structure is formed in the second light guide layer 10B so as to define a second pattern. Such a light guide layer is produced, for example, by bonding a first film having no pattern formed thereon and a second film having a desired fine pattern formed thereon by a lamination method, or by bonding with an adhesive (including a pressure-sensitive adhesive). For forming the fine pattern on the second film, laser patterning, direct laser imaging, laser drilling, masked or maskless laser or electron beam irradiation is used. Alternatively, individual properties may be imparted by printing, inkjet printing, screen printing or the like to change the material or refractive index value. Micro / nano dispensing, dosing, direct "writing", discrete laser sintering, micro electrical discharge machining (micro EDM), or micromachining, micro molding, imprinting, embossing and the like can also be used.

[0042] Next, an example of the planar shape and arrangement of the internal spaces 11A and 11B will be described with reference to FIG. 3. FIG. 3 is a schematic plan view of a first light guide member 110A included in a light emitting device 200A. Also, the shape of the first internal space 11A will be described with reference to FIGS. 4A, 4B and 4C. FIG. 4A is a schematic cross-sectional view of the first internal space 11A, FIG. 4B is a schematic plan view of the first internal space 11A, and FIG. 4C is a schematic plan view showing a variation of the first internal space 11A. Hereinafter, the first light guide member 110A will be described with reference to these drawings, but the following description can also be applied to the second light guide member 110B. In these drawings, the first light guide member 110A, the first light guide layer 10A, the first internal space 11A, the first front inclined surface ISa1 (inclination angle θa), the first rear inclined surface ISb1 (inclination angle θb), the first light source LS1, and the first region R1 may respectively correspond to the second light guide member 110B, the second light guide layer 10B, the second internal space 11B, the second front inclined surface ISa2 (inclination angle θb), the second rear inclined surface ISb2 (inclination angle θb), the second light source LS2, and the third region R3.

[0043] As shown in FIG. 3, the plurality of first internal spaces 11A are discretely arranged, for example, in a light guiding direction (+y direction) of the first light guiding layer 10A and a direction (x direction) orthogonal to the light guiding direction. With regard to the size of the first internal space 11A (length L, width W: see FIGS. 4A and 4B), for example, the length L is preferably 10 µm or more and 500 µm or less, and the width W is preferably 1 µm or more and 100 µm or less. Further, from the viewpoint of light extraction efficiency, the height H (see FIG. 4A) is preferably 1 µm or more and 100 µm or less.

[0044] Here, an example is shown in which the plurality of first internal spaces 11A are discretely arranged in the light guiding direction (+y direction) of the first light guiding layer 10A and the direction (x direction) orthogonal to the light guiding direction. However, the arrangement is not limited thereto, and the plurality of first internal spaces 11A may be discretely arranged in the light guiding direction (y direction) of the first light guiding layer 10A and a direction intersecting the light guiding direction. The discrete arrangement of the first internal spaces 11A can be appropriately set according to the shape of the first light guiding layer 10A, a required light distribution, and the like. Note that although light propagates in various directions within the first light guiding layer 10A, the +y direction is referred to as the light guiding direction, and light having a non-zero component in the +y direction is considered to propagate in the +y direction. The same applies to other directions. That is, light propagating in the -y direction includes all light having a non-zero component in the -y direction.

[0045] The multiple first internal spaces 11A are, for example, discretely arranged in the light-guiding direction and in directions intersecting the light-guiding direction. The discrete arrangement may or may not have periodicity (regularity) in at least one direction. However, from the viewpoint of mass production, it is preferable that the multiple first internal spaces 11A are uniformly arranged in the first region R1. For example, in the example shown in Figure 3, multiple first internal spaces 11A having substantially the same shape and a curved surface convex in the same direction are discretely and periodically arranged throughout the entire region R1 in the light-guiding direction (+y direction) and in the direction perpendicular to the light-guiding direction (x direction) of the first light-guiding layer 10A. In this case, the pitch Px is preferably, for example, 10 μm or more and 500 μm or less, and the pitch Py is preferably, for example, 10 μm or more and 500 μm or less. In the example shown in Figure 3, there are further internal spaces arranged with a 1 / 2 pitch offset in the y direction and x direction, respectively.

[0046] As shown in Figure 3, when viewed from the direction normal to the main surface of the first light guide layer 10A, the first forward inclined surface ISa1 forms a curved surface that is convex toward the first light source LS1. The first light source LS1 is, for example, an LED device, and a plurality of LED devices are arranged in the x direction. Since the light emitted from each of the plurality of LED devices has a spread in the y direction, having a curved surface that is convex toward the first light source LS1 allows the first forward inclined surface ISa1 to act uniformly on the light. However, if a coupling optical system is provided between the first light source LS1 and the light-receiving side surface of the first light guide layer 10A, and light with high parallelism (light with small spread in the y direction) is incident, the first forward inclined surface ISa1 may be parallel to the x direction. Also, instead of the discrete first internal space 11A, there may be an internal space such as a groove (for example, a triangular prism) extending in the x direction.

[0047] As shown in Figure 4A, the cross-sectional shape of the first internal space 11A is, for example, triangular. The inclination angle θa of the first forward inclined surface ISa1 on the first light source LS1 side is, for example, 10° to 70°. If the inclination angle θa is less than 10°, the controllability of light distribution decreases and the light extraction efficiency may also decrease. On the other hand, if the inclination angle θa exceeds 70°, for example, manufacturing may become difficult. The inclination angle θb of the first rear inclined surface ISb1 is, for example, 50° to 100°. If the inclination angle θb is less than 50°, stray light may be generated in unintended directions. On the other hand, if the inclination angle θb exceeds 100°, for example, manufacturing may become difficult. As shown in Figures 4B and 4C, the length L of the first internal space 11A is preferably 10 μm to 500 μm, and the width W is preferably 1 μm to 100 μm. The length L is, for example, twice or more the width W. The height H (see Figure 4A) is preferably 1 μm or more and 100 μm or less. Depending on the processing accuracy when forming the recess having the planar shape shown in Figure 4B, a recess having the planar shape shown in Figure 4C may be formed. Even in such cases, the planar shape of the internal space can be characterized by the length L and width W. The shape of the first light guide layer 10A, which is a curved surface convex toward the first light source LS1 on the first forward inclined surface ISa1, when viewed from the normal direction of the main surface, can be represented, for example, by a quartic curve. The first internal space 11A can be composed of a shaped film having a recess on its surface and an adhesive layer, for example, as will be described later.

[0048] The multiple first internal spaces 11A, which are light distribution control structures, have a ratio (occupancy rate) of the area of ​​the multiple first internal spaces 11A to the area of ​​the first region R1 of the first light guide layer 10A when the first light guide layer 10A is viewed from the direction normal to the main surface. Preferably, the upper limit is 1% to 80%, more preferably 50% or less, even more preferably 45% or less, and to obtain high transmittance and / or low haze value, it is preferably 30% or less, even more preferably 10% or less, and even more preferably 5% or less. For example, when the occupancy rate of the internal spaces is 50%, a haze value of 30% can be obtained. The occupancy rate in the first region R1 of the first internal spaces 11A may be uniform, or the occupancy rate may increase with increasing distance so that the brightness does not decrease even when the distance from the first light source LS1 increases. For mass production using the roll-to-roll method or roll-to-sheet method, it is preferable that the occupancy rate in the first region R1 of the first internal spaces 11A is uniform.

[0049] (Modification 1) The light-emitting device 200A1 according to Modification 1 of this embodiment will be described with reference to Figure 5. Figure 5 is a schematic cross-sectional view of the light-emitting device 200A1.

[0050] In the light-emitting device 200A described above, the first light-emitting control structure can direct at least a portion of the first light propagating within the first light guide layer 10A toward the first main surface 10Am, and the second light-emitting control structure can direct at least a portion of the second light propagating within the second light guide layer 10B toward the third main surface 10Bm. In contrast, as shown in Figure 5, the light-emitting device 200A1 differs from the light-emitting device 200A in that the first light-emitting control structure can direct at least a portion of the first light propagating within the first light guide layer 10A toward the second main surface 10An. That is, the first light-guiding member 111A of the light-emitting device 200A1 differs from the first light-guiding member 110A of the light-emitting device 200A in that it receives the first light emitted from the first light source LS1, propagates the light in the +y direction, and emits the light in the +z direction.

[0051] The combination of the direction in which the first light guide member emits the first light and the direction in which the second light guide member emits the second light is not limited to the illustrated example, and may be the reverse of the example in Figure 5, for example.

[0052] (Modification 2) A light-emitting device 200A2 according to Modification 2 of this embodiment will be described with reference to Figure 6. Figure 6 is a schematic cross-sectional view of the light-emitting device 200A2.

[0053] In the light-emitting device 200A described above, the direction of light guidance (+y direction) of the first light in the first light guide layer 10A of the first light guide member 110A and the direction of light guidance (+y direction) of the second light in the second light guide layer 10B of the second light guide member 110B are parallel. In contrast, as shown in Figure 6, the light-emitting device 200A2 differs from the light-emitting device 200A in that the direction of light guidance (+y direction) of the first light in the first light guide layer 10A of the first light guide member 110A and the direction of light guidance (-y direction) of the second light in the second light guide layer 10B of the second light guide member 112B are antiparallel. In the second light source LS2, the second light-receiving portion of the second light guide layer 10B is the side surface (light-receiving side surface) 10Bs2 of the second light guide layer 10B on the side of the second light source LS2.

[0054] The combination of the direction of light guidance for the first light in the first light guide layer 10A and the direction of light guidance for the second light in the second light guide layer 10B is not limited to the illustrated example, and may be the reverse of the example in Figure 6, for example.

[0055] (Embodiment 2) The light-emitting device 200B according to this embodiment will be described with reference to Figure 7. Figure 7 is a schematic cross-sectional view of the light-emitting device 200B. In the following, the differences between the light-emitting device 200B according to this embodiment and the light-emitting device 200A according to Embodiment 1 will be described in detail.

[0056] In the embodiment 1 described above, the first light distribution control structure and the second light distribution control structure are formed within the first light guide layer 10A and the second light guide layer 10B, respectively. In contrast, in this embodiment, as will be explained below, the first light guide member further has a first direction conversion layer, and the first light distribution control structure is formed in the first direction conversion layer, and the second light guide member further has a second direction conversion layer, and the second light distribution control structure is formed in the second direction conversion layer. The first and second direction conversion layers are sometimes called "light extraction layers".

[0057] As shown in Figure 7, the light-emitting device 200B includes a light guide member 100B, a first light source LS1, and a second light source LS2. The light guide member 100B includes a first light guide member 120A and a second light guide member 120B.

[0058] The first light guide member 120A includes a first light guide layer 10A and a first direction conversion layer 20A provided on the first main surface 10Am side of the first light guide layer 10A. The first direction conversion layer 20A has a first light distribution control structure.

[0059] The first light distribution control structure has a plurality of first internal spaces 26A having an interface (in this example, the first forward inclined surface ISa1) that directs light toward the first main surface 10Am side (-z direction) by internal total internal reflection. The first direction conversion layer 20A having a plurality of first internal spaces 26A is composed of a shaping film 24A having recesses 26A (indicated by the same reference numeral as the first internal spaces 26A) on its surface and an adhesive layer 54A. The adhesive layer 54A adheres the shaping film 24A to the first light guide layer 10A.

[0060] When the first light guide member 120A is viewed from the normal direction of the first main surface 10Am, a first region R1 in which the first light distribution control structure exists and a second region R2 in which the first light distribution control structure does not exist are arranged to define a predetermined first pattern. In this example, the first region is the region having the first direction conversion layer 20A, and the second region is the region not having the first direction conversion layer 20A. The plurality of first internal spaces 26A are formed, for example, uniformly within the first direction conversion layer 20A.

[0061] The second light guide member 120B has a second light guide layer 10B and a second direction conversion layer 20B provided on the third main surface 10Bm side of the second light guide layer 10B. The second direction conversion layer 20B has a second light distribution control structure. The second light distribution control structure has a plurality of second internal spaces 26B having an interface (in this example, a second forward inclined surface ISa2) that directs light toward the third main surface 10Bm side (-z direction) by internal total internal reflection. The second direction conversion layer 20B having a plurality of second internal spaces 26B is composed of a shaping film 24B having recesses 26B (indicated by the same reference numeral as the second internal spaces 26B) on its surface and an adhesive layer 54B. The adhesive layer 54B adheres the shaping film 24B and the second light guide layer 10B.

[0062] When the second light guide member 120B is viewed from the normal direction of the third main surface 10Bm, a third region R3 in which the second light distribution control structure exists and a fourth region R4 in which the second light distribution control structure does not exist are arranged to define a predetermined second pattern. In this example, the third region is the region having the second direction conversion layer 20B, and the fourth region is the region not having the second direction conversion layer 20B. The multiple second internal spaces 26B are formed, for example, uniformly within the second direction conversion layer 20B.

[0063] In the light-emitting device 200B of this embodiment, the first light distribution control structure is arranged to define the first pattern, and the second light distribution control structure is arranged to define the second pattern. Therefore, the first pattern can be emitted by the first light (invisible light), and the second pattern can be emitted by the second light (visible light). The light-emitting device 200B can emit patterns that show different two-dimensional codes in visible light and invisible light, while achieving high transparency.

[0064] The light-emitting device of this embodiment is not limited to the illustrated example. For example, similar to Modification 1 of Embodiment 1, the direction in which the first light guide member emits the first light and the direction in which the second light guide member emits the second light may be different (even antiparallel). For example, similar to Modification 2 of Embodiment 1, the light-guiding direction of the first light in the first light-guiding layer 10A and the light-guiding direction of the second light in the second light-guiding layer 10B may be different (even antiparallel).

[0065] (Modification 1) The light-emitting device 200B1 according to Modification 1 of this embodiment will be described with reference to Figure 8. Figure 8 is a schematic cross-sectional view of the light-emitting device 200B1.

[0066] As shown in Figure 8, the light-emitting device 200B1 includes a light guide member 100B1, a first light source LS1, and a second light source LS2. The light guide member 100B1 includes a first light guide member 121A and a second light guide member 121B.

[0067] The light-emitting device 200B1 differs from the light-emitting device 200B in that the first direction conversion layer 20A is provided on the second main surface 10An side of the first light guide layer 10A, and the second direction conversion layer 20B is provided on the fourth main surface 10Bn side of the second light guide layer 10B.

[0068] The first light guide member 121A includes a first light guide layer 10A and a first direction conversion layer 20A provided on the second main surface 10An side of the first light guide layer 10A. The first direction conversion layer 20A has a first light distribution control structure. The first direction conversion layer 20A is arranged on the second main surface 10An side of the first light guide layer 10A via an adhesive layer 52A. Furthermore, the shaping film 24A and the base layer 30A are bonded together by an adhesive layer 54A. The base layer 30A may be omitted.

[0069] The second light guide member 121B includes a second light guide layer 10B and a second direction conversion layer 20B provided on the fourth main surface 10Bn side of the second light guide layer 10B. The second direction conversion layer 20B has a second light distribution control structure. The second direction conversion layer 20B is arranged on the fourth main surface 10Bn side of the second light guide layer 10B via an adhesive layer 52B. The shaping film 24B and the base material layer 30B are bonded together by an adhesive layer 54B. The base material layer 30B may be omitted.

[0070] (Modification 2) A light-emitting device 200B2 according to Modification 2 of this embodiment will be described with reference to Figure 9. Figure 9 is a schematic cross-sectional view of the light-emitting device 200B2.

[0071] As shown in Figure 9, the light-emitting device 200B2 includes a light guide member 100B2, a first light source LS1, and a second light source LS2. The light guide member 100B2 includes a first light guide member 122A and a second light guide member 121B.

[0072] The light-emitting device 200B2 differs from the light-emitting device 200B in that the first region R1 and the second region R2 are distinguished by whether or not the recesses 26A of the shaping film 24A are filled with adhesive layer 54A. In this example, in the first region R1, the recesses 26A of the shaping film 24A are substantially filled with adhesive layer 54A, while in the second region R2, the recesses 26A of the shaping film 24A are not filled with adhesive layer 54A.

[0073] Similarly, the third region R3 and the fourth region R4 differ from the light-emitting device 200B in that they are distinguished by whether or not the recesses 26B of the shaping film 24B are filled with adhesive layer 54B. In this example, in the third region R3, the recesses 26B of the shaping film 24B are substantially filled with adhesive layer 54B, while in the fourth region R4, the recesses 26B of the shaping film 24B are not filled with adhesive layer 54B.

[0074] (Embodiment 3) The light-emitting device 200C according to this embodiment will be described with reference to Figure 10. Figure 10 is a schematic cross-sectional view of the light-emitting device 200C. In the following, the differences between the light-emitting device 200C according to this embodiment and the light-emitting device 200A according to Embodiment 1 will be described in detail.

[0075] As shown in Figure 10, the light-emitting device 200C includes a light guide member 100C, a first light source LS1, and a second light source LS2.

[0076] The light guide member 100C includes a first light guide layer 10A, a first light distribution control structure formed within the first light guide layer 10A, and a second light distribution control structure formed within the first light guide layer 10A. The first light distribution control structure has a plurality of first internal spaces 11A having an interface (in this example, a first forward inclined surface ISa1) that directs light toward the first main surface 10Am side by internal total internal reflection. In this example, a plurality of first internal spaces 11A are formed within the first light guide layer 10A. The second light distribution control structure has a plurality of second internal spaces 11B having an interface (in this example, a second forward inclined surface ISa2) that directs light toward the first main surface 10Am side by internal total internal reflection. In this example, a plurality of second internal spaces 11B are formed within the first light guide layer 10A.

[0077] In the light-emitting device 200C of this embodiment, the first light distribution control structure is arranged to define the first pattern, and the second light distribution control structure is arranged to define the second pattern. Therefore, the first pattern can be emitted by the first light (invisible light), and the second pattern can be emitted by the second light (visible light). That is, the first pattern can be emitted by the first light (invisible light), and the second pattern can be emitted by the second light (visible light). The light-emitting device 200C can emit patterns that represent different two-dimensional codes in visible light and invisible light, while achieving high transparency.

[0078] In the illustrated example, the first light source LS1 and the second light source LS2 emit first and second light, respectively, toward the side surface (light-receiving side surface) 10As1 of the first light guide layer 10A. However, the first light source LS1 and / or the second light source LS2 may emit light toward the side surface 10As2 opposite to side surface 10As1, or toward a part of the first main surface 10Am or the second main surface 10An (for example, the end of the first main surface 10Am or the second main surface 10An).

[0079] (Embodiment 4) The light-emitting device 200D according to this embodiment will be described with reference to Figure 11. Figure 11 is a schematic cross-sectional view of the light-emitting device 200D. In the following, the differences between the light-emitting device 200D according to this embodiment and the light-emitting device 200B according to Embodiment 2 will be described in detail.

[0080] As shown in Figure 11, the light-emitting device 200D includes a light guide member 100D, a first light source LS1, and a second light source LS2.

[0081] The light guide member 100D includes a first light guide layer 10A, a first direction conversion layer 20A provided on the second main surface 10An side of the first light guide layer 10A, and a second direction conversion layer 20B provided on the first main surface 10Am side of the first light guide layer 10A. The first direction conversion layer 20A has a first light distribution control structure. The second direction conversion layer 20B has a second light distribution control structure. The first light distribution control structure has a plurality of first internal spaces 26A having an interface (in this example, a first forward inclined surface ISa1) that directs light toward the first main surface 10Am side by internal total internal reflection. In this example, the plurality of first internal spaces 26A are formed within the first direction conversion layer 20A. The second light distribution control structure has a plurality of second internal spaces 26B having an interface (in this example, a second forward inclined surface ISa2) that directs light toward the first main surface 10Am side by internal total internal reflection. In this example, multiple second internal spaces 26B are formed within the second direction conversion layer 20B.

[0082] In the light-emitting device 200D of this embodiment, the first light distribution control structure is arranged to define the first pattern, and the second light distribution control structure is arranged to define the second pattern. Therefore, the first pattern can be emitted by the first light (invisible light), and the second pattern can be emitted by the second light (visible light). That is, the first pattern can be emitted by the first light (invisible light), and the second pattern can be emitted by the second light (visible light). The light-emitting device 200D can emit patterns that show different two-dimensional codes in visible light and invisible light, while achieving high transparency.

[0083] (Modification 1) The light-emitting device 200D1 according to Modification 1 of this embodiment will be described with reference to Figure 12. Figure 12 is a schematic cross-sectional view of the light-emitting device 200D1.

[0084] As shown in Figure 12, the light-emitting device 200D1 includes a light guide member 100D1, a first light source LS1, and a second light source LS2.

[0085] The light-emitting device 200D1 differs from the light-emitting device 200D in that the first region R1 and the second region R2 are distinguished by whether or not the recesses 26A of the shaping film 24A are filled with adhesive layer 54A. In this example, in the first region R1, the recesses 26A of the shaping film 24A are substantially filled with adhesive layer 54A, while in the second region R2, the recesses 26A of the shaping film 24A are not filled with adhesive layer 54A.

[0086] Similarly, the third region R3 and the fourth region R4 differ from the light-emitting device 200D in that they are distinguished by whether or not the recesses 26B of the shaping film 24B are filled with adhesive layer 54B. In this example, in the third region R3, the recesses 26B of the shaping film 24B are substantially filled with adhesive layer 54B, while in the fourth region R4, the recesses 26B of the shaping film 24B are not filled with adhesive layer 54B.

[0087] (Embodiment 5) The light-emitting device 200E according to this embodiment will be described with reference to Figure 13. Figure 13 is a schematic cross-sectional view of the light-emitting device 200E. In the following, the differences between the light-emitting device 200E according to this embodiment and the light-emitting device 200A according to Embodiment 1 will be described in detail.

[0088] As shown in Figure 13, the light-emitting device 200E includes a light guide member 110A and a first light source LS1. The light guide member 110A may have the same structure as the first light guide member 110A of the light-emitting device 200A. The light guide member 110A may also have the same structure as the second light guide member 110B of the light-emitting device 200A. The first light source LS1 of the light-emitting device 200E may be a light source that emits invisible light or a light source that emits visible light.

[0089] The light-emitting device 200E can emit a pattern representing a two-dimensional code while achieving high transparency. When the first light source LS1 emits invisible light, the first pattern representing the first two-dimensional code can be emitted using invisible light, and when the first light source LS1 emits visible light, the first pattern representing the first two-dimensional code can be emitted using visible light.

[0090] Figure 13 also shows a printed material 300 positioned on the back side of the light guide member 110A. The printed material 300 has, for example, a second two-dimensional code different from the first two-dimensional code printed on it. When the first light source LS1 is a light source that emits invisible light, when the first light source LS1 is ON, the first pattern is emitted by the first light (invisible light). When the first light source LS1 is OFF, since the light guide member 110A has a high visible light transmittance, the second two-dimensional code printed on the printed material 300 is visible to an observer of the light-emitting device 200E or detected by a visible light detection device via the light guide member 110A. In this way, the light-emitting device 200E can present mutually different information in visible light and invisible light, respectively. The printed material 300 may have patterns printed on it that are not limited to two-dimensional codes, but include letters, numbers, symbols, figures, pictures, designs, and combinations thereof.

[0091] (Modification 1) The light-emitting device 200E1 according to Modification 1 of this embodiment will be described with reference to Figure 14. Figure 14 is a schematic cross-sectional view of the light-emitting device 200E1.

[0092] As shown in Figure 14, the light-emitting device 200E1 includes a light guide member 120A and a first light source LS1.

[0093] The light-emitting device 200E1 differs from the light-emitting device 200E, which has a light-guiding member 110A, in that it has a light-guiding member 120A. The light-guiding member 120A may have the same structure as the first light-guiding member 120A of the light-emitting device 200B.

[0094] (Modification 2) A light-emitting device 200E2 according to Modification 2 of this embodiment will be described with reference to Figure 15. Figure 15 is a schematic cross-sectional view of the light-emitting device 200E2.

[0095] As shown in Figure 15, the light-emitting device 200E2 includes a light guide member 121A and a first light source LS1.

[0096] The light-emitting device 200E2 differs from the light-emitting device 200E, which has a light-guiding member 110A, in that it has a light-guiding member 121A. The light-guiding member 121A may have the same structure as the first light-guiding member 121A of the light-emitting device 200B1.

[0097] (Modification 3) The light-emitting device 200E3 according to Modification 3 of this embodiment will be described with reference to Figure 16. Figure 16 is a schematic cross-sectional view of the light-emitting device 200E3.

[0098] As shown in Figure 16, the light-emitting device 200E3 includes a light guide member 122A and a first light source LS1.

[0099] The light-emitting device 200E3 differs from the light-emitting device 200E, which has a light-guiding member 110A, in that it has a light-guiding member 122A. The light-guiding member 122A may have the same structure as the first light-guiding member 122A of the light-emitting device 200B2.

[0100] (Examples of preferred configurations of the light guide layer, shaping film, substrate layer, adhesive layer, and low refractive index layer) Preferred examples of each component of the light-emitting device according to embodiments of the present invention will be described.

[0101] The light guide layer is formed from a known material with high transmittance to visible light. For example, the light guide layer may be made from acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate (PC) resins, cycloolefin resins, or glass (e.g., quartz glass, alkali-free glass, borosilicate glass). The refractive index of the light guide layer is n. ＧＰ For example, it is between 1.40 and 1.80. Unless otherwise specified, the refractive index refers to the refractive index measured with an ellipsometer at a wavelength of 550 nm. The thickness of the light guide layer can be set appropriately depending on the application. For example, the thickness of the light guide layer is between 0.05 mm and 50 mm.

[0102] A shaping film for forming an internal space can be manufactured, for example, by the method described in Japanese Patent Publication No. 2013-524288. Specifically, a shaping film can be manufactured by coating the surface of a polymethyl methacrylate (PMMA) film with lacquer (FineCure RM-64, manufactured by Sanyo Chemical Industries, Ltd.), embossing an optical pattern onto the film surface containing the lacquer, and then curing the lacquer. The total thickness of the shaping film is, for example, 130 μm.

[0103] The thickness of the substrate layer is, for example, 1 μm to 1000 μm, preferably 10 μm to 100 μm, and more preferably 20 μm to 80 μm. The refractive index of the substrate layer is preferably 1.40 to 1.70, and more preferably 1.43 to 1.65, independently of each other.

[0104] The thickness of each adhesive layer is, 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 index of each adhesive layer is, for example, preferably 1.42 to 1.60, and more preferably 1.47 to 1.58. Furthermore, the refractive index of the adhesive layer is preferably close to the refractive index of the light guide layer, shaping film, or substrate layer in contact with it, and the absolute value of the difference in refractive index is preferably 0.2 or less.

[0105] Preferably, the adhesive layer that contacts the recesses on the surface of the shaped film and forms the internal space can adhere without filling the recesses on the surface of the shaped film. Suitable adhesives for forming such adhesive layers include those described in the present applicant's International Publication No. 2021 / 167090, International Publication No. 2021 / 167091, or International Publication No. 2022 / 176658. All disclosures of these applications are incorporated herein by reference. In particular, the polyester-based adhesive described in International Publication No. 2022 / 176658 is preferred.

[0106] Furthermore, a hard coat layer, an anti-reflective layer, an anti-fouling layer, etc., may be provided on the front surface of the light-emitting device. These can be formed using known materials.

[0107] The refractive index n of the low refractive index layer Ｌ The refractive index n is preferably 1.30 or less, more preferably 1.20 or less, and even more preferably 1.15 or less. The low refractive index layer is preferably solid, and its refractive index is preferably 1.05 or more. ＧＰ１ and the refractive index n of the second light guide layer 10B ＧＰ２ And the refractive index n of the low refractive index layer ＬThe difference is preferably 0.20 or more, more preferably 0.23 or more, and even more preferably 0.25 or more. A low refractive index layer with a refractive index of 1.30 or less can be formed using, for example, a porous material. The thickness of the low refractive index layer is, for example, 0.3 μm or more and 5 μm or less.

[0108] When the low refractive index layer is a porous material having internal voids, its porosity is preferably 35 volume% or more, more preferably 38 volume% or more, and particularly preferably 40 volume% or more. Within this range, a low refractive index layer with a particularly low refractive index can be formed. The upper limit of the porosity of the low refractive index layer is, for example, 90 volume% or less, and preferably 75 volume% or less. Within this range, a low refractive index layer with excellent strength can be formed. The porosity is a value calculated from the refractive index value measured with an ellipsometer using the Lorentz-Lorentz formula.

[0109] For the low refractive index layer, for example, a voided low refractive index layer disclosed in International Publication No. 2019 / 146628 can be used. All of the disclosures in International Publication No. 2019 / 146628 are incorporated herein by reference. Specifically, the voided low refractive index layer includes substantially spherical particles such as silica particles, silica particles with micropores, silica hollow nanoparticles, fibrous particles such as cellulose nanofibers, alumina nanofibers, silica nanofibers, and plate-like particles such as nanoclay composed of bentonite. In one embodiment, the voided low refractive index layer is a porous body in which particles (e.g., micropore particles) are directly chemically bonded to each other. In addition, at least some of the particles constituting the voided low refractive index layer may be bonded to each other via a small amount (e.g., less than or equal to the mass of the particles) of a binder component. The porosity and refractive index of the low refractive index layer can be adjusted by the particle size, particle size distribution, etc., of the particles constituting the low refractive index layer.

[0110] Methods for obtaining a low refractive index layer having voids include, for example, the methods described in Japanese Patent Publication No. 2010-189212, Japanese Patent Publication No. 2008-040171, Japanese Patent Publication No. 2006-011175, International Publication No. 2004 / 113966, and their references. All disclosures of Japanese Patent Publication No. 2010-189212, Japanese Patent Publication No. 2008-040171, Japanese Patent Publication No. 2006-011175, and International Publication No. 2004 / 113966 are incorporated herein by reference.

[0111] As a low refractive index layer having voids, a silica porous material can be suitably used. A silica porous material can be produced, for example, by the following methods: a method of hydrolyzing and polycondensing at least one of a silicon compound; hydrolyzable silanes and / or silsesquioxanes, and their partial hydrolysates and dehydrated condensates; a method using porous particles and / or hollow fine particles; a method of generating an aerogel layer using the springback phenomenon; a method of using a pulverized gel obtained by pulverizing a gel-like silicon compound obtained by the sol-gel method and chemically bonding the resulting pulverized fine-porous particles with a catalyst, etc. However, the low refractive index layer is not limited to a silica porous material, and the production method is not limited to the example production method; it can be produced by any production method. However, the porous layer is not limited to a silica porous material, and the production method is not limited to the example production method; it can be produced by any production method. Note that silsesquioxane is (RSio １．５ , R is a hydrocarbon group) is a silicon compound that has as its basic structural unit, SiO ２ Although strictly speaking different from silica, which has silosequioxane as its basic structural unit, porous materials containing silosequioxane as their basic structural unit are also referred to as silica porous materials or silica-based porous materials because they share a network structure cross-linked by siloxane bonds with silica.

[0112] A porous silica material may be composed of microporous particles of a gel-like silicon compound that are bonded together. Examples of microporous particles of a gel-like silicon compound include pulverized gel-like silicon compounds. A porous silica material can be formed, for example, by coating a substrate with a coating solution containing pulverized gel-like silicon compounds. The pulverized gel-like silicon compounds can be chemically bonded (e.g., siloxane bonds) by means of a catalyst, light irradiation, heating, etc.

[0113] According to embodiments of the present invention, a light-emitting device having high transparency and capable of emitting a pattern representing a two-dimensional code, and a light-guiding member suitably used in such a light-emitting device are provided. The light-emitting device according to embodiments of the present invention can emit patterns representing different two-dimensional codes using, for example, visible light and invisible light. The light-emitting device according to embodiments of the present invention can present different information using, for example, visible light and invisible light.

[0114] 10A: First light guide layer 10B: Second light guide layer 11A: First internal space 11B: Second internal space 20A: First direction conversion layer 20B: Second direction conversion layer 24A, 24B: Shaping film 26A, 26B: Recess 52A, 52B, 54A, 54B: Adhesive layer 100A, 100B, 100B1, 100B2, 100C, 100D, 100D1: Light guide member 200A, 200B, 200B1, 200B2, 200C, 200D, 200D1, 200E: Light-emitting device

Claims

1. A light guide member having a first light guide layer having a first main surface, a second main surface opposite to the first main surface, and a first light receiving portion that receives first light emitted from a light source, and a first light distribution control structure that can direct at least a portion of the first light propagating within the first light guide layer toward at least the first main surface side or the second main surface side, wherein, when viewed from the direction normal to the first main surface, a first region where the first light distribution control structure exists and a second region where the first light distribution control structure does not exist are arranged to define a first pattern indicating a first two-dimensional code, and the visible light transmittance is 70% or more and the haze value is 10% or less.

2. The light guide member according to claim 1, wherein the first light distribution control structure has a plurality of first internal spaces that form an interface that directs light toward the first main surface side or the second main surface side by total internal reflection.

3. The light guide member according to claim 2, wherein the plurality of first internal spaces of the first light distribution control structure are formed within the first light guide layer.

4. The light guide member according to claim 2, wherein the first light distribution control structure is formed in a first direction conversion layer provided on the first main surface side or the second main surface side of the first light guide layer.

5. A light-emitting device comprising a light-guiding member according to any one of claims 1 to 4, and a first light source that emits the first light toward the first light-receiving portion, wherein the first light emitted by the first light source includes invisible light.

6. The light-emitting device according to claim 5, wherein the first light emitted from the first light source includes infrared light.

7. The light guide member according to any one of claims 1 to 4, further comprising: a second conductive layer disposed on the first main surface side or the second main surface side of the first light guide layer, the second light guide layer having a third main surface, a fourth main surface opposite to the third main surface, and a second light receiving portion for receiving second light emitted from a light source; and a second light distribution control structure that can direct at least a portion of the second light propagating within the second light guide layer toward at least the third main surface side or the fourth main surface side, wherein, when viewed in plan from the direction normal to the third main surface, the third region where the second light distribution control structure exists and the fourth region where the second light distribution control structure does not exist are arranged to define a second pattern showing a second two-dimensional code different from the first two-dimensional code.

8. The light guide member according to claim 7, wherein the second light distribution control structure has a plurality of second internal spaces that form an interface that directs light toward the third main surface side or the fourth main surface side by internal total internal reflection.

9. The light guide member according to claim 8, wherein the plurality of second internal spaces of the second light distribution control structure are formed within the second light guide layer.

10. The light guide member according to claim 8, wherein the second light distribution control structure is formed in a second direction conversion layer provided on the third main surface side or the fourth main surface side of the second light guide layer.

11. The light guide member according to any one of claims 1 to 4, further comprising a second light distribution control structure that can direct at least a portion of the light propagating within the first light guide layer toward at least the first main surface side or the second main surface side, wherein, when viewed from a plan view from the direction normal to the first main surface, the third region where the second light distribution control structure exists and the fourth region where the second light distribution control structure does not exist are arranged to define a second pattern showing a second two-dimensional code different from the first two-dimensional code.

12. The light guide member according to claim 11, wherein the second light distribution control structure has a plurality of second internal spaces that form an interface that directs light toward the first main surface side or the second main surface side by internal total internal reflection.

13. The light guide member according to claim 12, wherein the plurality of second internal spaces of the second light distribution control structure are formed within the first light guide layer.

14. The light guide member according to claim 12, wherein the second light distribution control structure is formed in a second direction conversion layer provided on the first main surface side or the second main surface side of the first light guide layer.

15. A light-emitting device comprising a light guide member according to any one of claims 7 to 10, a first light source that emits the first light toward the first light-receiving unit, and a second light source that emits the second light toward the second light-receiving unit.

16. The light-emitting device according to claim 15, wherein the first light includes invisible light and the second light includes visible light.

17. A light-emitting device comprising: a light-guiding member according to any one of claims 11 to 14; a first light source that emits first light including invisible light toward the first light-receiving unit; and a second light source that emits second light including visible light toward the first light-receiving unit.

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