Planar light source

Abstract

To provide a planar light source with wiring installed on both sides of a substrate, configured to reduce occurrence of electrical conduction failure in the wiring.SOLUTION: A planar light source 300 includes: a substrate including a flexible insulating film; first wiring 12A installed on a first surface of the substrate; and second wiring 12B installed on a second surface which is opposite the first surface of the substrate. In plan view, the first wiring 12A intersects with the second wiring 12B. The first wiring 12A has a wide area 15 which is wider than a non-crossed section, which does not intersect with the second wiring 12B, at a crossed section 13 which intersects with the second wiring 12B.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a surface light source. [Background technology]

[0002] Planar light sources including a plurality of light-emitting elements such as light-emitting diodes are widely used, for example, as backlights for liquid crystal displays, etc. For example, Patent Document 1 discloses a planar light source including a plurality of light source units and a wiring board on which the plurality of light source units are arranged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-056369 Summary of the Invention [Problem to be solved by the invention]

[0004] An embodiment of the present invention provides a surface light source in which wiring is arranged on both sides of a substrate, and in which occurrence of electrical conduction problems in the wiring is reduced. [Means for solving the problem]

[0005] A surface light source according to one aspect of the present invention includes a substrate including a flexible insulating film, a first wiring disposed on a first surface of the substrate, and a second wiring disposed on a second surface of the substrate opposite the first surface. In a plan view, the first wiring intersects with the second wiring. The first wiring includes a wide region at an intersection where the first wiring intersects with the second wiring, the wide region being wider than a non-intersection where the first wiring does not intersect with the second wiring. [Effects of the Invention]

[0006] According to the surface light source of one embodiment of the present invention, in a surface light source in which wiring is arranged on both sides of a base material, it is possible to reduce occurrence of electrical conduction problems in the wiring. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic top view of a surface light source 300 according to the present embodiment. [Figure 2] FIG. 2 is a schematic top view of a portion of a surface light source 300 according to the present embodiment. [Figure 3] FIG. 2 is a schematic cross-sectional view of a light source unit 20 according to the present embodiment. [Figure 4] FIG. 4 is a schematic end view taken along line IV-IV in FIG. 2. [Figure 5] FIG. 2 is a schematic bottom view of a portion of the surface light source 300 according to the present embodiment. [Figure 6] FIG. 2 is an enlarged schematic bottom view of a portion of the surface light source 300 according to the present embodiment. [Figure 7] FIG. 2 is an enlarged view of an intersection 13 according to the present embodiment. [Figure 8] FIG. 10 is an enlarged view of an intersection C as a comparative example. [Figure 9] FIG. 5 is an enlarged view of a region R in FIG. [Figure 10] 10 is an enlarged view of an intersection 13 in Modification 1. FIG. [Figure 11] 10 is an enlarged view of an intersection 13 in Modification 2. FIG. [Figure 12] FIG. 13 is an enlarged view of an intersection 13 in Modification 3. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments will be described with reference to the drawings. The following embodiments are examples of surface light sources for embodying the technical concept of the present embodiments, and are not limited thereto. The dimensions, materials, shapes, relative arrangements, etc. of components described in the embodiments are not intended to limit the scope of the present disclosure, and are merely illustrative examples, unless otherwise specified. Note that the size, positional relationship, etc. of components shown in each drawing may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate the same or similar components, and detailed description will be omitted as appropriate. Furthermore, as cross-sectional views, end views showing only the cut surface may be used.

[0009] In the following description, terms indicating specific directions or positions (for example, "upper," "lower," and other terms including these terms) may be used. However, these terms are used merely to facilitate understanding of relative directions or positions in the referenced drawings. As long as the relationship of relative directions or positions indicated by terms such as "upper," "lower," etc. in the referenced drawings is the same, drawings other than those of the present disclosure, actual products, etc. may not be arranged in the same manner as in the referenced drawings.

[0010] In this specification, the positional relationship expressed as "above (or below)" includes, for example, when two components are assumed to exist, a case where the two components are in contact with each other and a case where the two components are not in contact with each other and one component is located above (or below) the other component. Furthermore, in this specification, unless otherwise specified, a component covering an object to be covered includes a case where the component is in contact with the object to be covered and directly covers it, and a case where the component is not in contact with the object to be covered and indirectly covers it. Furthermore, in this specification, "area" means the area in a planar view unless otherwise specified. Furthermore, "parallel" includes not only a case where two lines, sides, surfaces, etc. do not intersect even when extended, but also a case where the angle between the two lines, sides, surfaces, etc. is within a range of 10°.

[0011] <1. Embodiment> The configuration of the surface light source 300 according to the embodiment will be described below. In the following description, two directions parallel to the light-emitting surface of the surface light source 300 and perpendicular to each other are referred to as the X direction and the Y direction. A plane parallel to the X direction and the Y direction may be referred to as the XY plane. Furthermore, a direction perpendicular to the X direction and the Y direction may be referred to as the Z direction (or up-down direction). In the drawings, the direction of the Z axis arrow is referred to as the upward direction, and the direction opposite to the Z axis arrow is referred to as the downward direction. In the drawings, the side in the direction of the X axis arrow is referred to as the +X side, and the side opposite to the X axis arrow is referred to as the -X side. In the drawings, the side in the direction of the Y axis arrow is referred to as the +Y side, and the side opposite to the Y axis arrow is referred to as the -Y side.

[0012] (1.1.Surface light source 300) FIG. 1 is a schematic top view of the surface light source 300 as viewed from the light-emitting surface side. FIG. 2 is a schematic top view of a portion of the surface light source 300. FIG. 3 is a schematic cross-sectional view of the light source unit 20. The surface light source 300 includes a support 100 and a plurality of light source groups 200. The plurality of light source groups 200 are arranged on the support 100. The plurality of light source groups 200 are arranged side by side in the X direction. Each of the plurality of light source groups 200 includes a first light source 20A and a second light source 20B. The first light source 20A and the second light source 20B are arranged side by side in the Y direction perpendicular to the X direction. The surface light source 300 of this embodiment has a length in the X direction longer than its length in the Y direction. Below, each element constituting the surface light source 300 will be described in detail.

[0013] (1.2.Light source group 200) The surface light source 300 has a plurality of light source groups 200 arranged side by side in the X direction. Each of the plurality of light source groups 200 has a first light source 20A and a second light source 20B. The first light source 20A and the second light source 20B are arranged side by side in the Y direction. The first light source 20A and the second light source 20B may be referred to as a light source unit 20.

[0014] The light source unit 20 includes a light emitting element 21. The light emitting element 21 includes a semiconductor laminate. The semiconductor laminate includes, for example, a substrate such as sapphire or gallium nitride, an n-type semiconductor layer disposed on the substrate, a p-type semiconductor layer, and a light emitting layer sandwiched between the n-type semiconductor layer and the p-type semiconductor layer. The light emitting element 21 also includes an n-side electrode electrically connected to the n-type semiconductor layer and a p-side electrode electrically connected to the p-type semiconductor layer. The n-side electrode and the p-side electrode form part of the lower surface of the light emitting element 21. The light source unit 20 also includes a pair of positive and negative electrodes 22. The pair of positive and negative electrodes 22 form part of the lower surface of the light source unit 20. One of the pair of electrodes 22 is electrically connected to the p-side electrode, and the other is electrically connected to the n-side electrode.

[0015] The light source unit 20 includes one light emitting element 21. Each of the light source units 20 of the first light source 20A and the second light source 20B may include a plurality of light emitting elements 21. The emission peak wavelengths of the plurality of light emitting elements included in each light source unit 20 may be the same or different.

[0016] The light source section 20 may further include a light-transmissive member (hereinafter referred to as a light-source light-transmissive member 23). The light-source light-transmissive member 23 covers the upper and side surfaces of the light-emitting element 21. The light-source light-transmissive member 23 can protect the light-emitting element 21. The light-source light-transmissive member 23 may be disposed so as to expose at least a portion of the upper surface of the light-emitting element 21. This makes it easier to reduce the size of the light source section 20 in the vertical direction.

[0017] For example, the light source light-transmissive member 23 is translucent to the light emitted by the light emitting element 21. The light source light-transmissive member 23 includes a translucent resin and may further include a phosphor. For example, a silicone resin or an epoxy resin can be used as the translucent resin. Furthermore, the phosphor can be an yttrium-aluminum-garnet phosphor (for example, Y3(Al,Ga)5O 12 :Ce), lutetium aluminum garnet phosphors (e.g., Lu3(Al,Ga)5O 12 :Ce), terbium aluminum garnet phosphors (e.g., Tb3(Al,Ga)5O12 :Ce), CCA-based phosphors (e.g., Ca 10 (PO4)6C 12 :Eu), SAE-based phosphors (e.g., Sr4Al 14 O 25 :Eu), chlorosilicate phosphors (e.g., Ca8MgSiO 16 Cl2:Eu), β-sialon phosphors (e.g., (Si,Al)3(O,N)4:Eu) or α-sialon phosphors (e.g., Ca(Si,Al) 12 (O,N) 16 :Eu), nitride-based phosphors such as SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu) or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu), KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2Si 0.99 Al 0.01 F 5.99 Fluoride-based phosphors such as 3.5MgO·0.5MgF2·GeO2:Mn) or MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), phosphors having a perovskite structure (e.g., CsPb(F,Cl,Br,I)3), or quantum dot phosphors (e.g., CdSe, InP, AgInS2, or AgInSe2) can be used. The phosphor added to the light-source translucent member 23 may be one type of phosphor or multiple types of phosphors.

[0018] The light source unit 20 may further include a covering member 24. The covering member 24 is disposed on the lower surface of the light emitting element 21. The covering member 24 is disposed so that the lower surfaces of the electrodes 22 of the light source unit 20 are exposed from the covering member 24. The covering member 24 is also disposed on the lower surface of the light source translucent member 23 that covers the side surface of the light emitting element 21.

[0019] The covering member 24 is reflective to the light emitted by the light-emitting element 21. For example, a resin material containing a gas such as nitrogen or oxygen, or a resin material containing light-scattering particles can be used for the covering member 24. For example, a thermoplastic resin such as an acrylic resin, a polycarbonate resin, a cyclic polyolefin resin, or a polyethylene terephthalate, or a thermosetting resin such as an epoxy resin or a silicone resin can be used for the resin material for the covering member 24. For example, particles of titanium oxide, silicon oxide, aluminum oxide, zinc oxide, or glass can be used for the light-scattering particles for the covering member 24. The covering member 24 may contain both a gas and light-scattering particles.

[0020] The light source unit 20 may further include a light adjustment member (hereinafter referred to as light-source light adjustment member 25). The light-source light adjustment member 25 is reflective and translucent to the light emitted by the light-emitting element 21. The light-source light adjustment member 25 is disposed above the light-source translucent member 23, and adjusts the amount and emission direction of light emitted from the upper surface of the light-source translucent member 23. The transmittance of the light-source light adjustment member 25 with respect to the peak wavelength of the light-emitting element 21 is, for example, preferably 1% or more and 50% or less, and more preferably 3% or more and 30% or less.

[0021] The light source light adjustment member 25 can be made of, for example, a resin member containing light scattering particles. The resin member of the light source light adjustment member 25 can be made of the same material as the resin member of the covering member 24. The light scattering particles of the light source light adjustment member 25 can be made of the same material as the light scattering particles of the covering member 24. The light source light adjustment member 25 may also be made of, for example, a metal member such as aluminum or silver, or a dielectric multilayer film.

[0022] The shape of the light source unit 20 in a planar view is not particularly limited. The shape of the light source unit 20 in a planar view can be, for example, a circle, a triangle, a rectangle, a hexagon, or an octagon. When the shape of the light source unit 20 in a planar view is a rectangle, a pair of outer edges of the light source unit 20 may be parallel to the X direction or may be inclined with respect to the X direction. In this embodiment, the pair of outer edges of the light source unit 20 are inclined at 45° with respect to the X direction.

[0023] (1.3. Light-guiding member 70) FIG. 4 is a schematic end view of the surface light source 300. FIG. 5 is a schematic bottom view of a portion of the surface light source 300. FIG. 6 is an enlarged schematic bottom view of a portion of the surface light source 300. The surface light source 300 may include a light-guiding member 70 having holes 70H in which the light source units 20 are disposed. The light-guiding member 70 is a member that is translucent to the light emitted by the light source units 20. The transmittance of the light-guiding member 70 with respect to the peak wavelength of the light source units 20 is, for example, preferably 60% or more, and more preferably 80% or more. In this embodiment, the surface light source 300 includes a first light-guiding member 70A in which the first light source 20A is disposed, and a second light-guiding member 70B in which the second light source 20B is disposed. The first light-guiding member 70A and the second light-guiding member 70B may be referred to as light-guiding members 70.

[0024] The light-guiding member 70 has a first light-guiding surface 701 that serves as the light-emitting surface of the surface light source 300, and a second light-guiding surface 702 located on the opposite side of the first light-guiding surface 701. The light-guiding member 70 continuously surrounds the light source unit 20 in a planar view. In this embodiment, the light-guiding member 70 has a hole 70H that penetrates from the first light-guiding surface 701 to the second light-guiding surface 702. The light source unit 20 is disposed in the hole 70H of the light-guiding member 70. In this embodiment, the hole 70H has a circular shape in a planar view. The hole 70H may have an elliptical shape or a polygonal shape such as a triangle, a rectangle, a hexagon, or an octagon in a planar view. Note that the hole 70H may be a recess that is open only on the second light-guiding surface 702 side of the light-guiding member 70.

[0025] In this embodiment, each of the multiple light-guiding members 70 is a different light-emitting region 300A. One light-emitting region 300A can be used as a driving unit for local dimming. The number of light-emitting regions 300A constituting the surface light source 300 is not particularly limited. For example, the surface light source 300 may include one light-emitting region 300A, or, as in this embodiment, the surface light source 300 may include multiple light-emitting regions 300A. Furthermore, by arranging multiple surface light sources 300, a surface light source device with a larger area may be created.

[0026] The first light guide member 70A and the second light guide member 70B are preferably arranged with a gap 70G between them. This reduces warping of the support 100 caused by the difference in thermal expansion coefficient between the light guide member 70 and the support 100. This reduces the occurrence of cracks in the conductive member 50. Furthermore, it is preferable that the plurality of light guide members 70 are arranged with a gap between them.

[0027] The shape of the recesses 71 of the light-guiding member 70 is not particularly limited. The shape of the recesses 71 of the light-guiding member 70 of this embodiment may include a linear portion. In this specification, linear includes a straight line, a curved line, a bent line, or the like. For example, the shape of the recesses 71 of the light-guiding member 70 in a plan view may include a V-shaped or L-shaped portion extending in two directions. The shape of the recesses 71 of the light-guiding member 70 in a plan view may be a circle, a triangle, a rectangle, a hexagon, an octagon, or the like. Furthermore, the shape and / or number of the recesses 71 of the first light-guiding member 70A and the shape and / or number of the recesses 71 of the second light-guiding member 70B may be the same as or different from each other.

[0028] The light-guiding member 70 may be made of the same material as the resin member of the covering member 24. Alternatively, the light-guiding member 70 may be made of glass or the like. The light-guiding member 70 may contain a phosphor or light-scattering particles.

[0029] The thickness of the light-guiding member 70 is preferably, for example, 150 μm or more and 800 μm or less. The light-guiding member 70 may be configured as a single layer in the vertical direction, or may be configured as a laminate of multiple layers. When the light-guiding member 70 is configured as a laminate, a light-transmitting adhesive may be disposed between each layer. Each layer of the laminate may use a different type of main material.

[0030] (1.4. Translucent member 80) The surface light source 300 may include a light-transmitting member 80. The light-transmitting member 80 is a member that is transmissive to light emitted by the light source unit 20. The light-transmitting member 80 has a first light-transmitting portion 81 and a second light-transmitting portion 82. In this embodiment, the first light-transmitting portion 81 and the second light-transmitting portion 82 are separate bodies. The first light-transmitting portion 81 and the second light-transmitting portion 82 may be integrally formed from the same material. The transmittance of each of the first light-transmitting portion 81 and the second light-transmitting portion 82 with respect to the peak wavelength of the light source unit 20 is, for example, preferably 60% or more, and more preferably 80% or more.

[0031] The first light-transmitting portion 81 is preferably in contact with a side surface of the light source portion 20. This makes it easier for light from the light source portion 20 to enter the first light-transmitting portion 81. The first light-transmitting portion 81 is preferably in contact with the light-guiding member 70. This makes it easier for light from the light source portion 20 to enter the light-guiding member 70.

[0032] The first light-transmitting portion 81 may be composed of a single layer in the vertical direction, or may be composed of a laminate of multiple layers. The first light-transmitting portion 81 may also contain phosphors and light-scattering particles. When the first light-transmitting portion 81 is a laminate, each layer may or may not contain phosphors and / or light-scattering particles. For example, the first light-transmitting portion 81 may be composed of a layer containing phosphors and a layer not containing phosphors. The first light-transmitting portion 81 may be made of a material similar to that of the resin member of the covering member 24, for example.

[0033] The second light-transmitting portion 82 is located above the light source unit 20. The second light-transmitting portion 82 is located above the first light-transmitting portion 81. It is preferable that the second light-transmitting portion 82 contacts the upper surface of the light source unit 20 and / or the upper surface of the first light-transmitting portion 81. This makes it easier to make the surface light source 300 smaller in size in the vertical direction.

[0034] The second light-transmitting portion 82 may be made of, for example, the same material as the resin material of the covering member 24. Alternatively, a sheet-shaped optical transparent adhesive (OCA) may be used as the second light-transmitting portion 82. The second light-transmitting portion 82 may contain a phosphor or light-scattering particles.

[0035] (1.5. Light Adjustment Member 90) The surface light source 300 may include a light adjusting member 90. The light adjusting member 90 has reflectivity and translucency for light emitted from the light source unit 20. A portion of the light emitted from the light source unit 20 is reflected by the light adjusting member 90, and another portion is transmitted through the light adjusting member 90. The transmittance of the light adjusting member 90 for the peak wavelength of the light source unit 20 is lower than the transmittance of the light guide member 70 for the peak wavelength of the light source unit 20. For example, the transmittance of the light adjusting member 90 for the peak wavelength of the light source unit 20 is preferably 1% or more and 50% or less, and more preferably 3% or more and 30% or less. The light adjusting member 90 may be configured as a single layer or a laminate of multiple layers.

[0036] The light adjustment member 90 is disposed above the light source unit 20. In a plan view, the light adjustment member 90 and the light source unit 20 overlap, and the light adjustment member 90 is located above the light source unit 20 at the overlapping portion. By positioning the light adjustment member 90 above the light source unit 20, it is possible to prevent the area directly above the light source unit 20 from becoming too bright.

[0037] It is preferable that at least a part of the outer edge of the light adjustment member 90 is located outside the outer edges of the holes 70H of the light guide member 70 in a plan view. This can prevent the areas near the outer edges of the holes 70H from becoming too bright. In a plan view, the entire outer edge of the light adjustment member 90 may be located outside the outer edges of the holes 70H. This can further prevent the areas near the outer edges of the holes 70H from becoming too bright.

[0038] The light adjustment member 90 may have a light adjustment through-hole 90A. When the light adjustment member 90 has the light adjustment through-hole 90A, it becomes easy to adjust the brightness in the area directly above the light adjustment member 90. For example, by changing the size and position of the light adjustment through-hole 90A, it is possible to adjust the light from the light source unit 20 that is blocked by the light adjustment member 90. This makes it easy to adjust the brightness in the area directly above the light adjustment member 90, which makes it easier to reduce brightness unevenness of the surface light source 300.

[0039] The light adjusting member 90 can be configured by a resin member and a reflector contained in the resin member. For example, the same material as the resin member of the covering member 24 can be used as the resin member of the light adjusting member 90. The same material as the light scattering particles of the covering member 24 can be used as the reflector of the light adjusting member 90. A gas such as nitrogen or oxygen may be used as the reflector of the light adjusting member 90. Furthermore, the light adjusting member 90 may contain both light scattering particles and a gas as the reflector.

[0040] (1.6.Support 100) The support 100 is a member on which the plurality of light source groups 200 are placed. The support 100 has a base material 11. The base material 11 is a flexible insulating film. The base material 11 may be composed of a single layer in the vertical direction, or may be composed of a laminate of multiple layers. The material of the base material 11 may be, for example, a resin such as polyimide.

[0041] The substrate 11 includes a first surface 11A and a second surface 11B located on the opposite side of the first surface 11A. In this embodiment, the first surface 11A is the lower surface of the substrate 11. However, the first surface 11A may also be the upper surface of the substrate 11.

[0042] The first wiring 12A is disposed on the first surface 11A of the base material 11. The first wiring 12A is electrically connected to at least one of the first light source 20A and the second light source 20B. The first wiring 12A may be made of a metal wire such as a copper wire.

[0043] The second wiring 12B is disposed on the second surface 11B of the substrate 11. The second wiring 12B may be a printed wiring. The material of the second wiring 12B may be a conductive paste containing a resin and metal particles contained in the resin. The resin of the second wiring 12B may be, for example, an epoxy resin or a phenol resin. The metal particles of the second wiring 12B may be, for example, copper or silver particles.

[0044] The support 100 may further have a first adhesive layer 31 disposed on the substrate 11, a reflective member 40 disposed on the first adhesive layer 31, and a second adhesive layer 32 disposed on the reflective member 40.

[0045] The first adhesive layer 31 is disposed between the base material 11 and the reflective member 40, and bonds the base material 11 and the reflective member 40 together. The first adhesive layer 31 can be made of, for example, a resin member containing light-scattering particles. The resin member of the first adhesive layer 31 can be made of, for example, the same material as the resin member of the covering member 24. The light-scattering particles of the first adhesive layer 31 can be made of, for example, the same material as the light-scattering particles of the covering member 24. The first adhesive layer 31 may be made of a sheet-like optical transparent pressure-sensitive adhesive.

[0046] The reflective member 40 has reflectivity to the light emitted by the light source unit 20. It is disposed below the light source unit 20. The reflective member 40 can be composed of a resin member and a reflector contained in the resin member. For example, the same material as the resin member of the covering member 24 can be used as the resin member of the reflective member 40. The same material as the light scattering particles of the covering member 24 can be used as the reflector material of the reflective member 40. A gas such as nitrogen or oxygen may be used as the reflector of the reflective member 40. Furthermore, the reflective member 40 may contain both light scattering particles and a gas as the reflector.

[0047] The second adhesive layer 32 is disposed between the reflecting member 40 and the light source unit 20, and bonds the reflecting member 40 and the light source unit 20 together. The light source unit 20 is disposed on the second adhesive layer 32. The second adhesive layer 32 can be formed, for example, of a resin member containing light-scattering particles. The resin member of the second adhesive layer 32 can be made of, for example, the same material as the resin member of the covering member 24. The light-scattering particles of the second adhesive layer 32 can be made of, for example, the same material as the light-scattering particles of the covering member 24. The second adhesive layer 32 may be made of a sheet-like optical transparent pressure-sensitive adhesive.

[0048] The support 100 further includes a conductive member 50. For example, a conductive paste can be used as the material of the conductive member 50. The conductive member 50 is in contact with the electrode 22 of the light source unit 20.

[0049] The conductive member 50 has a connection portion 51 and a wiring portion 52. The connection portion 51 penetrates the second adhesive layer 32, the reflective member 40, the first adhesive layer 31, and the base material 11 in the vertical direction. The wiring portion 52 electrically connects the connection portion 51 and the first wiring 12A. The connection portion 51 and the wiring portion 52 can be integrally formed from the same material.

[0050] It is preferable that the conductive member 50 is connected to the first wiring 12A at multiple locations. This makes it easier to reduce the possibility of a portion of the electrical circuit being disconnected. In this embodiment, the conductive member 50 and the first wiring 12A are connected at two locations, the first wiring portion 52A and the second wiring portion 52B. Note that the conductive member 50 may also be connected to the first wiring 12A at one location.

[0051] A pair of conductive members 50 are arranged apart from each other in correspondence with the pair of positive and negative electrodes 22 of the light source unit 20. The connection portion 51 of one conductive member 50 is connected to the positive electrode 22 below the light source unit 20, and the connection portion 51 of the other conductive member 50 is connected to the negative electrode 22 below the light source unit 20.

[0052] The support 100 preferably further includes an insulating layer 60 that protects the lower surface of the base material 11. In this embodiment, the insulating layer 60 is disposed on the lower surface of the base material 11 and covers the first wiring 12A. The insulating layer 60 may be made of, for example, an epoxy resin, a urethane resin, or an acrylic resin.

[0053] (1.7. Wide Area 15) Fig. 7 is a diagram showing an intersection 13 where a first wiring 12A and a second wiring 12B intersect, Fig. 8 is a diagram showing an intersection C as a comparative example, and Fig. 9 is an enlarged view of a region R in Fig. 4.

[0054] In a plan view, the first wiring 12A has an intersection 13 where it intersects with the second wiring 12B. At the intersection 13 where it intersects with the second wiring 12B, the first wiring 12A has a wide region 15 that is wider in the X direction (hereinafter simply referred to as width) than a non-intersection 14 that does not intersect with the second wiring 12B. In a plan view, the wide region 15 has the shape of a part of a diamond, and is formed across the intersection 13 and the non-intersection 14.

[0055] Specifically, the width of wide region 15 increases linearly from width D1 of first wiring 12A at non-intersection portion 14 to maximum width D2 of first wiring 12A at intersection portion 13, with the width being widest near the center in the Y direction of intersection portion 13. The lengths of widths D1 and D2 may be set appropriately, and at intersection portion 13, angle α of side L1 of first wiring 12A with respect to side L2 of second wiring 12B is preferably 5° or more and 85° or less, and more preferably 15° or more and 75° or less.

[0056] In the comparative example, the width D of the side La of the first wiring P is constant across the intersection C. Therefore, cracks that may occur in the second wiring Q due to an impact from the first wiring P may linearly connect across the section S corresponding to the Y direction of the intersection C. If cracks are linearly connected across the section S of the second wiring Q in this way, there is a risk of a problem such as a significant decrease in the conductivity of the second wiring Q. In contrast, the surface light source 300 according to this embodiment has the above-mentioned configuration, and therefore, when the flexible base material 11 is bent by an external force, cracks that may occur in the second wiring 12B due to an impact from the first wiring 12A can be prevented from linearly connecting across the section S1 corresponding to the Y direction of the intersection 13.

[0057] A hole 16 is opened in a part of the region where the intersection 13 is arranged in the base material 11. A part of the second wiring 12B is arranged as a via 12D in the hole 16. The first wiring 12A and the second wiring 12B are electrically connected through the via 12D provided in the hole 16.

[0058] (1.8.Summary) As described above, the surface light source 300 according to this embodiment includes a substrate 11 including a flexible insulating film, a first wiring 12A disposed on a first surface 11A of the substrate 11, and a second wiring 12B disposed on a second surface 11B opposite the first surface 11A of the substrate 11. In a plan view, the first wiring 12A intersects with the second wiring 12B. The first wiring 12A includes, at an intersection 13 where the first wiring 12A intersects with the second wiring 12B, a wide region 15 that is wider than a non-intersection portion 14 that does not intersect with the second wiring 12B.

[0059] With this configuration, when the flexible substrate 11 is bent by an external force, cracks that may occur in the second wiring 12B due to an impact from the first wiring 12A can be prevented from extending across the section S1 corresponding to the Y direction of the intersection 13, thereby reducing the occurrence of electrical conductivity problems in the wiring.

[0060] (1.9. Variations) In the modifications according to this embodiment, the shape of the wide region 15 differs from that of the above embodiment. The differences from the above embodiment will be mainly described below. Fig. 10 is an enlarged view of the intersection 13 in Modification 1. Fig. 11 is an enlarged view of the intersection 13 in Modification 2. Fig. 12 is an enlarged view of the intersection 13 in Modification 3.

[0061] In the first modification, in a plan view, the wide region 15 includes a pair of trapezoidal portions 15a formed across the intersection 13 and the non-intersection 14, and a rectangular portion 15b formed within the intersection 13. In other words, the wide region 15 has an octagonal shape formed by combining the trapezoidal portion 15a and the rectangular portion 15b, a portion of which is formed as the non-intersection 14. If the width of the non-intersection 14 at the apex of the trapezoidal portion 15a is D3 and the width of the rectangular portion 15b formed within the intersection 13 is D4, then D4 > D3. The lengths of the widths D3 and D4 may be set as appropriate, and even in this configuration, the same effect as in the above embodiment can be obtained.

[0062] In Modification 2, wide region 15 is circular in plan view and is formed within intersection 13. The portions of intersection 13 other than wide region 15 are formed to have the same width as non-intersection 14. If the width of non-intersection 14 is D5 and the diameter of wide region 15 at intersection 13 is D6, then D6 > D5. The lengths of width D5 and width D6 can be set appropriately, and even in this configuration, the same effects as those of the above embodiment can be obtained.

[0063] In Modification 3, wide region 15 is a rectangle with rounded corners in a plan view, and is formed across intersection 13 and non-intersection 14. Wide region 15 is connected to non-intersection 14 only at one end in the Y-axis direction. If the width of non-intersection 14 is D7 and the width of wide region 15 at intersection 13 is D8, then D8 > D7. The lengths of widths D7 and D8 can be set appropriately, and even in this configuration, the same effects as those of the above embodiment can be obtained.

[0064] <2. Other embodiments> Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above. For example, the shape of the wide region 15 at the intersection 13 is not limited to the specific form disclosed in the above embodiment. For example, it may be elliptical in plan view.

[0065] In the above embodiment, a metal wire is used for the first wiring 12A, and a conductive paste containing metal particles contained in resin is used for the second wiring 12B, but this is not limiting. For example, a conductive paste containing metal particles may be used as the material for the first wiring 12A, and a metal wire such as a copper wire may be used as the material for the second wiring 12B.

[0066] The present specification includes the following embodiments. (Appendix 1) a substrate including a flexible insulating film; a first wiring disposed on a first surface of the base material; a second wiring disposed on a second surface of the base opposite to the first surface, In a plan view, the first wiring intersects with the second wiring, The planar light source includes a wide region at an intersection where the first wiring intersects with the second wiring, the wide region being wider than a non-intersection where the first wiring does not intersect with the second wiring. (Appendix 2) 2. The surface light source according to claim 1, wherein the wide region is formed across the intersection portion and the non-intersection portion in a plan view. (Appendix 3) 3. The surface light source according to claim 1, wherein at the intersection, the side of the first wiring has an angle of 5° or more and 85° or less with respect to the side of the second wiring. (Appendix 4) 2. The surface light source according to claim 1, wherein the wide region is formed within the intersection in a plan view. (Appendix 5) 5. The surface light source according to any one of claims 1 to 4, wherein the wide region is rectangular or circular with rounded corners in a plan view. (Appendix 6) A surface light source as described in any one of appendixes 1 to 5, wherein a hole is opened in the region of the base material where the intersection is arranged, and the first wiring and the second wiring are electrically connected through the hole. (Appendix 7) 7. The surface light source according to any one of claims 1 to 6, wherein the first wiring is a metal wiring, and the second wiring is a printed wiring made of resin containing metal particles. (Appendix 8) 7. The surface light source according to claim 6, wherein the second wiring is disposed in the hole. (Appendix 9) 9. The surface light source according to any one of claims 1 to 8, wherein the substrate contains polyimide.

[0067] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. All forms that can be implemented by a person skilled in the art through appropriate design modifications based on the above-described embodiments of the present invention also fall within the scope of the present invention as long as they include the gist of the present invention. In addition, a person skilled in the art may come up with various modifications and alterations within the scope of the concept of the present invention, and these modifications and alterations also fall within the scope of the present invention. [Explanation of symbols]

[0068] 11: base material, 11A: first surface, 11B: second surface, 12A: first wiring, 12B: second wiring, 12D: via, 13: intersection portion, 14: non-intersection portion, 15: wide region, 15a: trapezoidal portion, 15b: rectangular portion, 16: hole portion, 20: light source portion, 20A: first light source, 20B: second light source, 21: light-emitting element, 22: electrode, 23: light-source transmissive member, 24: covering member, 25: light-source light adjustment member, 31: first adhesive layer, 32: second adhesive layer, 40: reflective member, 50: conductive portion member, 51: connection portion, 52: wiring portion, 52A: first wiring portion, 52B: second wiring portion, 60: insulating layer, 70: light guide member, 70A: first light guide member, 70B: second light guide member, 70G: gap, 70H: hole portion, 71: recess, 80: light-transmitting member, 81: first light-transmitting portion, 82: second light-transmitting portion, 90: light adjustment member, 90A: light adjustment through-hole, 100: support, 200: light source group, 300: surface light source, 300A: light-emitting region, 701: first light-guiding surface, 702: second light-guiding surface

Claims

1. a substrate including a flexible insulating film; a first wiring disposed on a first surface of the base material; a second wiring disposed on a second surface of the base opposite to the first surface, In a plan view, the first wiring intersects with the second wiring, The surface light source, wherein the first wiring has a wide region at an intersection where the first wiring intersects with the second wiring, the wide region being wider than a non-intersection where the first wiring does not intersect with the second wiring.

2. The surface light source according to claim 1 , wherein the wide region is formed across the intersection portion and the non-intersection portion in a plan view.

3. The surface light source according to claim 1 , wherein the side of the first wiring has an angle of 5° or more and 85° or less with respect to the side of the second wiring at the intersection.

4. The surface light source according to claim 1 , wherein the wide region is formed within the intersection in a plan view.

5. The surface light source according to claim 3 , wherein the wide region has a rectangular or circular shape with rounded corners in a plan view.

6. A surface light source as described in any one of claims 1 to 5, wherein a hole is opened in the region where the intersection is arranged in the base material, and the first wiring and the second wiring are electrically connected through the hole.

7. 7. The surface light source according to claim 6, wherein the first wiring is a metal wiring, and the second wiring is a printed wiring made of resin containing metal particles.

8. The surface light source according to claim 7 , wherein the second wiring is disposed in the hole.

9. 6. The surface light source according to claim 1, wherein the substrate includes polyimide.

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