Light-emitting device, planar light source, and liquid crystal display device

Abstract

To provide a light-emitting device with a narrow light distribution characteristic.SOLUTION: A light-emitting device includes: a support body which has a recessed section defined by a wall portion and a bottom surface enclosed by the wall portion; a light-emitting element mounted on the bottom surface; and a translucent member disposed on the wall portion and the light-emitting element. The upper surface of the translucent member comprises a first surface, a second surface which is enclosed by the first surface in a planar view and protrudes upward relative to the first surface in a cross-sectional view and a curved third surface which connects the first surface and the second surface in the cross-sectional view. The upper surface of the wall portion has a first inclined surface that is inclined relative to the bottom surface, and the third surface is positioned above the first inclined surface.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a light-emitting device, a surface light source, and a liquid crystal display device. [Background technology]

[0002] A known example of a light-emitting device capable of controlling light distribution is one that includes a support having a wall portion, a light-emitting element placed on the support and surrounded by the wall portion in a planar view, a first light-transmissive member that covers the light-emitting element and the wall portion, and a light-shielding member that covers the first light-transmissive member (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2022 / 196300 Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a light emitting device having a light distribution characteristic of narrow light distribution. [Means for solving the problem]

[0005] A light emitting device according to one embodiment of the present disclosure comprises a support having a recess defined by a wall portion and a bottom surface surrounded by the wall portion, a light emitting element placed on the bottom surface, and a translucent member disposed on the wall portion and the light emitting element, wherein an upper surface of the translucent member comprises a first surface, a second surface surrounded by the first surface in a plan view and convex upwardly relative to the first surface in a cross-sectional view, and a curved third surface connecting the first surface and the second surface in a cross-sectional view, wherein an upper surface of the wall portion has a first inclined surface inclined relative to the bottom surface, and the third surface is located above the first inclined surface. Effect of the Invention

[0006] According to an embodiment of the present disclosure, it is possible to provide a light emitting device having a light distribution characteristic of a narrow light distribution. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a schematic top view illustrating the light emitting device according to the first embodiment. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Diagram 3] 2 is a schematic top view of the light emitting device of FIG. 1 from which a first light-transmissive member and a second light-transmissive member are omitted. [Figure 4] 2 is a schematic top view showing the leads of the light emitting device of FIG. 1. [Diagram 5] 2 is a schematic bottom view of the light emitting device of FIG. 1. [Figure 6] FIG. 2 is a schematic top view illustrating a light emitting device according to a first modified example of the first embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 11 is a schematic cross-sectional view illustrating a light emitting device according to Modification 2 of the first embodiment. [Figure 9] FIG. 11 is a schematic cross-sectional view illustrating a light emitting device according to a third modified example of the first embodiment. [Figure 10] FIG. 11 is a schematic cross-sectional view illustrating a light emitting device according to a fourth modified example of the first embodiment. [Figure 11] FIG. 13 is a schematic cross-sectional view illustrating a light emitting device according to a fifth modified example of the first embodiment. [Figure 12] FIG. 13 is a schematic cross-sectional view illustrating a light emitting device according to a sixth modified example of the first embodiment. [Figure 13] 1 is a schematic top view illustrating a surface light source according to a first embodiment. FIG. [Figure 14] FIG. 14 is a schematic cross-sectional view taken along line XIV-XIV in FIG. [Figure 15] 1 is a schematic partial cross-sectional view illustrating a surface light source including a partition member; [Figure 16] FIG. 11 is a configuration diagram illustrating a liquid crystal display device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, a description will be given of an embodiment of the invention with reference to the drawings. In the following description, terms indicating specific directions or positions (for example, "upper", "lower", and other terms including these terms) will be used as necessary. However, the use of these terms is for the purpose of facilitating understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present invention. In addition, parts with the same reference numerals appearing in multiple drawings indicate the same or equivalent parts or members.

[0009] Furthermore, the embodiments shown below are illustrative of light-emitting devices and the like for embodying the technical ideas of the present invention, and do not limit the present invention to the following. Furthermore, unless otherwise specified, the dimensions, materials, shapes, and relative arrangements of the components described below are intended to be illustrative, and not to limit the scope of the present invention. Furthermore, the contents described in one embodiment are applicable to other embodiments and modified examples. Furthermore, the size and positional relationship of the members shown in the drawings may be exaggerated to clarify the explanation. Furthermore, in order to avoid the drawings becoming overly complicated, a schematic diagram in which some elements are omitted, or an end view showing only the cut surface may be used as a cross-sectional view. Furthermore, in this specification, "parallel" means that a deviation of about ±5° from parallel is permitted.

[0010] First embodiment (Light emitting device 20) FIG. 1 is a schematic top view illustrating the light emitting device according to the first embodiment. FIG. 2 is a schematic cross-sectional view along the II-II line in FIG. 1. FIG. 3 is a schematic top view of the light emitting device in FIG. 1 with the first light-transmissive member and the second light-transmissive member omitted. FIG. 4 is a schematic top view showing the leads of the light emitting device in FIG. 1. FIG. 5 is a schematic bottom view of the light emitting device in FIG. 1. Note that the X direction and / or Y direction shown in each figure may be referred to as the horizontal direction, the Z direction as the up-down direction, and the direction from the Z- side to the Z+ side as the upward direction. In addition, the expression "planar view" in this specification refers to the case when viewed from the Z+ side.

[0011] As shown in FIGS. 1 to 5, the light emitting device 20 includes a support 21, a light emitting element 24, and a light-transmitting member 25. The light emitting element 24 is a light-transmitting member.

[0012] The support 21 has a recess 21x defined by a wall portion 23A and a bottom surface 21a surrounded by the wall portion 23A. The light-emitting element 24 is placed on the bottom surface 21a. The light-transmitting member 25 is disposed on the wall portion 23A and the light-emitting element 24. In the example shown in FIG. 2, the bottom surface 21a is a flat surface.

[0013] The light-transmitting member 25 has an upper surface 251 and a side surface 252 connected to the upper surface 251. The upper surface 251 includes a first surface 251a, a second surface 251b that is surrounded by the first surface 251a in a plan view and that is convex upward from the first surface 251a in a cross-sectional view, and a curved third surface 251c that connects the first surface 251a and the second surface 251b in a cross-sectional view. In the example shown in FIG. 2, the first surface 251a is a flat surface parallel to the bottom surface 21a. The third surface 251c has a radius of curvature of, for example, 0.05 mm or more and 0.15 mm or less.

[0014] The wall portion 23A has an upper surface 231 and an outer side surface 232 connected to the upper surface 231. Furthermore, the wall portion 23A has an inner side surface 233 connecting the upper surface 231 and the bottom surface 21a. The recess 21x is defined by the bottom surface 21a and the inner side surface 233 of the wall portion 23A. The upper surface 231 is disposed so as to surround the bottom surface 21a in a plan view. The upper surface 231 has a first inclined surface 231a inclined with respect to the bottom surface 21a. The first inclined surface 231a inclines downward toward the outside of the support body 21. The inclination angle of the first inclined surface 231a with respect to the bottom surface 21a is, for example, 45 degrees. The third surface 251c constituting the upper surface 251 of the light-transmitting member 25 is located above the first inclined surface 231a. 1 to 5, the upper surface 231 of the wall portion 23A further has a flat surface 231b connected to the upper side of the first inclined surface 231a and a flat surface 231c connected to the lower side of the first inclined surface 231a. In the example shown in FIGS. 1 to 5, the flat surfaces 231b and 231c are parallel to the bottom surface 21a. The outer surface 232 of the wall portion 23A is located on the same plane as the side surface 252 of the light-transmitting member 25, for example. The outer surface 232 of the wall portion 23A and the side surface 252 of the light-transmitting member 25 are perpendicular to the bottom surface 21a, for example.

[0015] The light-transmitting member 25 has a second surface 251b that is convex upward from the first surface 251a, so that the light from the light-emitting element 24 is refracted and emitted from the second surface 251b, and the light-emitting device can emit light with a narrow light distribution. Furthermore, in the light-emitting device 20, the upper surface 231 of the wall portion 23A has a first inclined surface 231a that is inclined with respect to the bottom surface 21a, and the curved third surface 251c is located above the first inclined surface 231a. As a result, the light that reaches the third surface 251c can be reflected by the third surface 251c and reach the first inclined surface 231a. Then, the light that reaches the first inclined surface 231a can be emitted directly from the side surface 252 of the light-transmitting member 25, or can be reflected by the first inclined surface 231a and emitted from the side surface 252 of the light-transmitting member 25. When the light that reaches the third surface 251c is reflected by the third surface 251c and is emitted from the side surface 252 of the light-transmitting member 25, it can travel in a lateral or diagonal downward direction without traveling in an obliquely upward direction. This allows light having a light distribution characteristic of a narrow light distribution to be emitted from the light-transmitting member 25 without impeding the narrow light distribution.

[0016] The third surface 251c is preferably located on the upper end side of the first inclined surface 231a (i.e., the side closer to the flat surface 231b). This makes it easier for the light reflected by the third surface 251c to strike the first inclined surface 231a. As a result, the light reflected by the third surface 251c strikes the flat surface 231c of the wall portion 23A, reducing the amount of light emitted obliquely upward from the side surface 252 of the light-transmitting member 25 and increasing the amount of light emitted laterally or downward from the side surface 252 of the light-transmitting member 25, which contributes to narrowing the light distribution.

[0017] The distance in the Z direction between the first surface 251a and the flat surface 231b is preferably ¼ to ⅓ of the distance in the Z direction between the first surface 251a and the flat surface 231c. If this distance is ¼ or more, more light can pass between the first surface 251a and the flat surface 231b, so that the amount of light emitted laterally or downward from the side surface 252 of the light-transmitting member 25 increases, which contributes to narrowing the light distribution. On the other hand, if this distance is ⅓ or less, it can contribute to making the light-emitting device 20 more compact.

[0018] In the example shown in FIG. 1, the third surface 251c is arranged circumferentially. As shown in FIG. 1, the third surface 251c can contribute to narrow light distribution even if the entire third surface 251c does not overlap the first inclined surface 231a. That is, in at least one cross section intersecting the circumferential direction in which the third surface 251c is arranged, the third surface 251c can contribute to narrow light distribution if it is located above the first inclined surface 231a. For example, as shown in FIG. 1, when the shape of the first inclined surface 231a in a plan view is rectangular, the third surface 251c is not located above the first inclined surface 231a in the regions of the four corners of the first inclined surface 231a, and the third surface 251c is located above the first inclined surface 231a in the regions between the corners.

[0019] 1 to 5, the light emitting device 20 further includes leads 22a and 22b, light emitting elements 24a and 24b, and wires 28a, 28b, and 28c. The light emitting elements 24a and 24b are disposed on the leads 22a and 22b.

[0020] The support 21 includes the leads 22a and 22b, and a resin member 23. The resin member 23 includes a wall portion 23A and a holding portion 23B that is located between the leads 22a and 22b and holds the leads 22a and 22b. Parts of the upper surfaces of the leads 22a and 22b are exposed in the recess 21x and form part of the bottom surface 21a. On the lower surface of the light emitting device 20, the leads 22a and 22b are exposed from the wall portion 23A. The light emitting element 24a is disposed on the lead 22a exposed from the wall portion 23A. The light emitting element 24b is disposed on the lead 22b exposed from the wall portion 23A. That is, the light emitting elements 24a and 24b are disposed on the bottom surface 21a.

[0021] Wire 28a connects the upper surface of lead 22a to the upper surface of light-emitting element 24a. Wire 28b connects the upper surface of lead 22b to the upper surface of light-emitting element 24b. Wire 28c connects the upper surface of light-emitting element 24a to the upper surface of light-emitting element 24b. Light-emitting elements 24a and 24b are connected in series via wires 28a, 28b, and 28c.

[0022] In the example shown in FIG. 2, the light-transmitting member 25 is composed of a first light-transmitting member 26 and a second light-transmitting member 27. The first light-transmitting member 26 is located in the recess 21x of the support 21. The first light-transmitting member 26 covers the light-emitting elements 24a and 24b, the bottom surface 21a, and the inner side surface 233 of the wall portion 23A. The upper surface 26a of the first light-transmitting member 26 is located in the same plane as the plane 231b constituting the upper surface 231 of the wall portion 23A. The second light-transmitting member 27 is disposed on the upper surface 231 of the wall portion 23A including the first inclined surface 231a and the upper surface 26a of the first light-transmitting member 26. In the example shown in FIG. 1, the second surface 251b of the light-transmitting member 25 is circular in a plan view.

[0023] In Fig. 1 and Fig. 2, C1 indicates the center of the light-emitting element 24 and the center of the second surface 251b. Also, C2 indicates the center of the bottom surface 21a. In the example shown in Fig. 1 and Fig. 2, the center of the light-emitting element 24 is different from the center of the bottom surface 21a and coincides with the center of the second surface 251b. The reason why the center of the light-emitting element 24 is different from the center of the bottom surface 21a is to reliably arrange the wires 28a to 28c at the positions shown in Fig. 3 while miniaturizing the entire light-emitting device 20 in a plan view. By making the center of the light-emitting element 24 coincide with the center of the second surface 251b, it is possible to emit light in an even direction with respect to the center of the second surface 251b, and therefore it is possible to reduce the bias of the luminance distribution. Note that, when the light-emitting device 20 has a plurality of light-emitting elements 24, the center of the light-emitting element 24 is the center of the overall outline of the plurality of light-emitting elements 24.

[0024] Each member included in the light emitting device 20 will be described in detail below.

[0025] (Leads 22a and 22b) The leads 22a and 22b are members for electrically connecting to either the negative or positive electrodes of the pair of electrodes of the light emitting elements 24a and 24b to pass electricity to the light emitting elements 24a and 24b. The material of the leads 22a and 22b may be, for example, a metal such as copper, aluminum, gold, silver, iron, nickel, or alloys thereof, phosphor bronze, or copper containing iron. The leads 22a and 22b may be formed into a predetermined shape by, for example, pressing such as rolling, punching, and extrusion, etching by wet or dry etching, or a combination of these. It is preferable to use copper, which has high heat dissipation properties, as the material of the leads 22a and 22b. The leads 22a and 22b may have a single-layer structure or a multilayer structure.

[0026] For example, in order to improve reflectivity, the leads 22a and 22b may be partially or entirely plated with a metal such as silver, aluminum, copper, or gold in a single layer or laminate structure. When a silver-containing metal layer is formed on the outermost surface of the leads 22a and 22b, it is preferable to provide a protective film such as silicon oxide on the surface of the silver-containing metal layer. This can reduce the risk of the silver-containing metal layer being discolored by sulfur components in the air. Examples of methods for forming the protective film include known methods such as vacuum processes such as sputtering or atomic layer deposition (ALD). For example, silicon oxide or aluminum oxide can be used as the material for the protective film.

[0027] As shown in FIG. 4, it is preferable that a groove 21y is provided on the upper surface of the leads 22a and 22b. The groove 21y is recessed downward from the upper surface of the leads 22a and 22b. The groove 21y can be formed by etching or the above-mentioned press processing. The groove 21y may be disposed around the light emitting elements 24a and 24b in a plan view, or may be disposed elsewhere. In the example shown in FIG. 4, a part of the wall portion 23A is disposed within the groove 21y. This increases the contact area between the wall portion 23A and the leads 22a and 22b, improving the adhesion between the wall portion 23A and the leads 22a and 22b.

[0028] 5, when the leads 22a and 22b are exposed from the wall portion 23A on the lower surface of the light emitting device 20, heat from the light emitting device 20 is easily transferred to the substrate on which the light emitting device 20 is mounted via the leads 22a and 22b. This improves the heat dissipation of the light emitting device 20. In addition, the lower surfaces of the leads 22a and 22b exposed from the wall portion 23A can be used as external terminals for electrical connection to the substrate. The light emitting device 20 may include three or more leads.

[0029] (Wall part 23A, holding part 23B) The wall portion 23A is a portion of the support 21 that covers a part of the upper surface and the outer side surface of the leads 22a and 22b. The leads 22a and 22b may or may not be exposed from the outer side surface 232 of the wall portion 23A. The holding portion 23B is a portion of the support 21 that connects the inner sides of the leads 22a and 22b facing each other. The upper surface of the holding portion 23B and the upper surfaces of the leads 22a and 22b can be located on the same plane. The holding portion 23B, together with a part of the upper surfaces of the leads 22a and 22b, constitute the bottom surface 21a of the support 21. In the example shown in FIG. 1 to FIG. 3, the wall portion 23A and the holding portion 23B are integrally connected by the same material, for example.

[0030] 2, the first inclined surface 231a of the wall portion 23A is a straight line in a cross-sectional view. However, the first inclined surface 231a is not limited to this, and may be a curved line that rises in a direction away from the leads 22a and 22b or that is recessed in a direction toward the leads 22a and 22b.

[0031] The inner side surface 233 of the wall portion 23A may be an inclined surface inclined with respect to the upper surfaces of the leads 22a and 22b, or may be a vertical surface perpendicular to the upper surfaces of the leads 22a and 22b. In the example shown in Fig. 2, the inner side surface 233 of the wall portion 23A is an inclined surface that slopes outward from the upper surfaces of the leads 22a and 22b in the upward direction. This makes it easier for light from the light emitting elements 24a and 24b to be reflected upward.

[0032] The wall 23A and the holding portion 23B may be made of, for example, a resin containing a light scattering material. This allows the light from the light emitting element 24 to be reflected toward the light-transmitting member 25, and also ensures insulation between the lead 22a and the lead 22b. Examples of the resin include known materials such as thermosetting resins and thermoplastic resins. Examples of the thermoplastic resin include polyphthalamide resin, polybutylene terephthalate (PBT), and unsaturated polyester. Examples of the thermosetting resin include epoxy resin, modified epoxy resin, silicone resin, and modified silicone resin. It is preferable to use a thermosetting resin such as epoxy resin or silicone resin, which has excellent heat resistance and light resistance, as the material of the wall 23A and the holding portion 23B.

[0033] As the light scattering material, a material that does not easily absorb light from the light emitting elements 24a and 24b and has a large difference in refractive index with respect to the resin can be used. Examples of such light scattering materials include titanium oxide, zinc oxide, silicon oxide, zirconium oxide, aluminum oxide, and aluminum nitride. The light scattering material can be contained in the resin in an amount of, for example, 10% by weight to 90% by weight.

[0034] In the example shown in Fig. 3, the shape defined by the lower end of the inner surface 233 of the wall portion 23A in a plan view is a rectangle with curved corners. That is, in a plan view, the shape of the bottom surface 21a is a rectangle with curved corners. Also, in a plan view, the shape defined by the upper end of the inner surface 233 of the wall portion 23A is a rectangle. Note that the shape defined by the lower end of the inner surface 233 of the wall portion 23A in a plan view (i.e., the shape of the bottom surface 21a) and the shape defined by the upper end of the inner surface 233 of the wall portion 23A are not limited to being a rectangle with curved corners, and may be a rectangle with orthogonal corners or a circle.

[0035] (Light-emitting elements 24a and 24b) The light emitting elements 24a and 24b are semiconductor elements that emit light by themselves when a voltage is applied, and known semiconductor elements composed of nitride semiconductors or the like can be used. Examples of the light emitting elements 24a and 24b include LED chips. The light emitting elements 24a and 24b include a semiconductor laminate. The semiconductor laminate includes an n-type semiconductor layer, a p-type semiconductor layer, and a light emitting layer sandwiched between them. The light emitting layer may have a structure such as a double heterojunction or a single quantum well (SQW), or may have a structure having a group of light emitting layers such as a multiple quantum well (MQW). The emission peak wavelength of the light emitting layer can be appropriately selected depending on the purpose. The light emitting layer can be configured to be capable of emitting, for example, visible light or ultraviolet light. A semiconductor laminate including such a light emitting layer can be, for example, In x Al y Ga 1-x-y This includes all semiconductors with compositions in which the composition ratios x and y in the chemical formula N (0≦x, 0≦y, x+y≦1) are changed within their respective ranges.

[0036] The semiconductor laminate may have a structure including one or more light-emitting layers between an n-type semiconductor layer and a p-type semiconductor layer, or may have a structure in which a structure including an n-type semiconductor layer, a light-emitting layer, and a p-type semiconductor layer in order is repeated multiple times. When the semiconductor laminate includes multiple light-emitting layers, the multiple light-emitting layers may include light-emitting layers with different emission peak wavelengths or light-emitting layers with the same emission peak wavelength. The same emission peak wavelength includes a case where the emission peak wavelengths vary within +10 nm. The combination of emission peak wavelengths between the multiple light-emitting layers can be appropriately selected. For example, when the semiconductor laminate includes two light-emitting layers, the light-emitting layers can be selected from combinations such as blue light and blue light, green light and green light, red light and red light, ultraviolet light and ultraviolet light, blue light and green light, blue light and ultraviolet light, blue light and red light, or green light and red light. Each light-emitting layer may include multiple active layers with different emission peak wavelengths or multiple active layers with the same emission peak wavelength.

[0037] In the example shown in FIG. 3, two light-emitting elements (light-emitting elements 24a and 24b) are mounted on one light-emitting device 20. However, the present invention is not limited to this, and one light-emitting device 20 may have only one light-emitting element mounted thereon, or may have three or more light-emitting elements mounted thereon. When one light-emitting device 20 includes a plurality of light-emitting elements, a plurality of light-emitting elements having the same emission peak wavelength may be combined in order to improve the luminous intensity of the light-emitting device 20 as a whole. In addition, color reproducibility may be improved by combining a plurality of light-emitting elements having different emission peak wavelengths, for example, to correspond to red, green, and blue. When the light-emitting device 20 includes a plurality of light-emitting elements, all of the light-emitting elements may be connected in series, may be connected in parallel, or may be connected in series and in parallel in combination. The light-emitting elements may be mounted face-up with the surface on which the electrodes are formed facing up, or may be mounted flip-chip with the surface on which the electrodes are formed facing down.

[0038] (Translucent member 25) The light-transmissive member 25 is a member for controlling the light distribution characteristic of the light emitting device 20. The first light-transmissive member 26 and the second light-transmissive member 27 constituting the light-transmissive member 25 are transmissive to the light from the light emitting element 24.

[0039] [First translucent member 26] The first light-transmissive member 26 may contain a wavelength converting material. This facilitates chromaticity adjustment of the light-emitting device 20. In the example shown in FIG. 2, the first light-transmissive member 26 is a resin containing a wavelength converting material. Examples of resins used for the first light-transmissive member 26 include known resins having translucency, such as silicone resins and epoxy resins. Among them, silicone resins (specifically, phenyl silicone resins or dimethyl silicone resins, etc.) that are highly reliable can be preferably used. Note that glass can be used instead of the resin.

[0040] The wavelength conversion material used in the first light-transmissive member 26 may be one type or multiple types. The wavelength conversion material contained in the first light-transmissive member 26 may be dispersed or unevenly distributed. A known phosphor can be used as the wavelength conversion material. The phosphor is excited by the light emitted by the light-emitting element 24 and emits light of a wavelength different from the wavelength of the light emitted by the light-emitting element 24. The phosphor can be an yttrium-aluminum-garnet phosphor (for example, (Y,Gd)3(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)5O 12 :Ce), CCA phosphors (e.g., Ca 10 (PO4)6Cl2:Eu), SAE phosphors (e.g., Sr4Al 14 O 25 :Eu), chlorosilicate phosphors (e.g., Ca8MgSi4O 16(Cl2:Eu), silicate phosphors (e.g., (Ba,Sr,Ca,Mg)2SiO4: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) and other oxynitride phosphors, LSN phosphors (e.g., (La,Y)3Si6N 11 :Ce), BSESN phosphors (e.g., (Ba,Sr)2Si5N8:Eu), SLA phosphors (e.g., SrLiAl3N4:Eu), CASN phosphors (e.g., CaAlSiN3:Eu) or SCASN phosphors (e.g., (Sr,Ca)AlSiN3:Eu) and other nitride phosphors, KSF phosphors (e.g., K2SiF6:Mn), KSAF phosphors (e.g., K2(Si 1-x Al x )F 6-x :Mn where 0 < x < 1. ) or MGF phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn) and other fluoride phosphors, quantum dots having a perovskite structure (e.g., (Cs,FA,MA)(Pb,Sn)(F,Cl,Br,I)3 where FA and MA represent formamidinium and methylammonium, respectively.), II-VI group quantum dots (e.g., CdSe), III-V group quantum dots (e.g., InP), or quantum dots having a chalcopyrite structure (e.g., (Ag,Cu)(In,Ga)(S,Se)2) can be used.

[0041] [Second light transmissive member 27] In the example shown in FIG. 2, the second light-transmissive member 27 covers the upper surface 231 of the wall portion 23A including the first inclined surface 231a and the upper surface 26a of the first light-transmissive member 26. In the example shown in FIG. 2, the second light-transmissive member 27 covers the upper surfaces of the light-emitting elements 24a and 24b via the first light-transmissive member 26. However, this is not limited to the above, and the second light-transmissive member 27 may contact the upper surfaces of the light-emitting elements 24a and 24b to cover the light-emitting elements 24a and 24b. That is, the light-transmissive member 25 may be composed only of the second light-transmissive member 27. When the light-transmissive member 25 is composed only of the second light-transmissive member 27, for example, the wavelength conversion material is unevenly arranged only in the region inside the recess 21x.

[0042] 2, the second surface of the second light-transmissive member 27, i.e., the second surface 251b of the light-transmissive member 25, includes a flat surface 251b1 located above the light-emitting element 24, a second inclined surface 251b2, and a curved surface 251b3 connecting the second inclined surface 251b2 and the flat surface 251b1. In a plan view, the curved surface 251b3 is located outside the flat surface 251b1, and the second inclined surface 251b2 is located outside the curved surface 251b3.

[0043] The plane 251b1 is, for example, parallel to the bottom surface 21a. Since the light emitted from the plane 251b1 has a higher brightness than the light emitted from the second inclined surface 251b2 and the curved surface 251b3, a high-brightness region corresponding to the light emitted from the plane 251b1 is obtained in the brightness distribution. Since this high-brightness region corresponds to the size and shape of the plane 251b1 in a planar view, the size and shape of the high-brightness region can be changed by changing the size and shape of the plane 251b1 in a planar view. In the example shown in FIG. 1, the shape of the plane 251b1 in a planar view is circular, so a circular high-brightness region is obtained. Also, in the example shown in FIG. 2, the plane 251b1 is located inside the recess 21x in a planar view.

[0044] The second inclined surface 251b2 is, for example, a flat surface that forms an angle of 8 degrees or more and 16 degrees or less with respect to the normal line of the bottom surface 21a. The closer the angle of the second inclined surface 251b2 with respect to the normal line of the bottom surface 21a is to 0 degrees, that is, the closer the second inclined surface 251b2 is to a surface perpendicular to the bottom surface 21a, the more light is totally reflected, which can contribute to narrowing the light distribution.

[0045] The curved surface 251b3 has a radius of curvature of, for example, 0.1 mm or more and 0.9 mm or less. When the second surface 251b includes the curved surface 251b3, it is possible to refract light emitted from the light emitting element 24 and reaching the curved surface 251b3 straight up, which contributes to narrowing the light distribution.

[0046] The radius of curvature of the third surface 251c is preferably smaller than the radius of curvature of the curved surface 251b3. By reducing the radius of curvature of the third surface 251c, the second inclined surface 251b2 can be lengthened. This reduces the light reflected by the third surface 251c and increases the light emitted to the outside from the second inclined surface 251b2, thereby improving the light extraction efficiency.

[0047] The distance in the Z direction between the first surface 251a and the flat surface 251b1 is, for example, 0.8 mm or more and 1.2 mm or less. The distance in the Z direction between the first surface 251a and the flat surface 251b1 is, for example, ½ or more of the height of the entire light emitting device 20 in the Z direction.

[0048] The shape of the second surface 251b is not limited to the example shown in Fig. 2. For example, instead of the curved surface 251b3, an inclined surface having an inclination angle with respect to the normal line of the bottom surface 21a larger than that of the second inclined surface 251b2 may be provided.

[0049] The shape of the second surface 251b may not include the curved surface 251b3, and the second inclined surface 251b2 and the flat surface 251b1 may be directly connected. In this case, the second inclined surface 251b2 may be a curved surface that is convex outward instead of a flat surface. Also, the flat surface 251b1 may be a curved surface that is convex upward.

[0050] 2, the second light-transmissive member 27 may be made of a resin. The resin used for the second light-transmissive member 27 may be the same as the resin used for the first light-transmissive member 26. The resin used for the second light-transmissive member 27 may be the same material as the resin used for the first light-transmissive member 26, or a different material.

[0051] 2, the second light-transmissive member 27 does not include the wavelength conversion member and light scattering material described above. This can reduce the light emitted from the second light-transmissive member 27 from spreading over a wide range, which can contribute to narrowing the light distribution. Note that the second light-transmissive member 27 may include a wavelength conversion material and / or a light scattering material to the extent that it does not impede narrowing the light distribution.

[0052] Modification of the First Embodiment FIG. 6 is a schematic top view illustrating a light emitting device according to Modification 1 of the first embodiment. FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. 6. As shown in FIG. 6, the light emitting device 20A differs from the light emitting device 20 in the outer shape of the second surface 251b (i.e., the outer shape of the second inclined surface 251b2) and the outer shape of the third surface 251c. In the light emitting device 20, the outer shapes of the second surface 251b and the third surface 251c in a planar view are circular. In contrast, in the light emitting device 20A, the outer shapes of the second surface 251b and the third surface 251c in a planar view are rectangular with curved corners. In the light emitting device 20A, like the light emitting device 20, light with a narrow light distribution can be emitted from the second surface 251b of the light-transmitting member 25.

[0053] 6, in the light emitting device 20A, the shape of the plane 251b1 of the second surface 251b in a plan view is rectangular. Therefore, the high brightness area corresponding to the light emitted from the plane 251b1 of the second surface 251b is rectangular in a plan view. When the light emitting devices are arranged in a matrix on the substrate as a surface light source, the use of the light emitting device 20A in which the shape of the high brightness area in a plan view is rectangular can reduce the brightness unevenness between the light emitting devices 20A.

[0054] Fig. 8 is a schematic cross-sectional view illustrating a light emitting device according to Modification 2 of the first embodiment. As shown in Fig. 8, the light emitting device 20B differs from the light emitting device 20 in the radius of curvature of the curved surface 251b3 in cross-sectional view. The light emitting device 20B has a larger radius of curvature of the curved surface 251b3 than the light emitting device 20 in cross-sectional view.

[0055] In the light emitting device 20B, similarly to the light emitting device 20, the light with a narrow light distribution can be emitted from the second surface 251b of the light-transmitting member 25.

[0056] Fig. 9 is a schematic cross-sectional view illustrating a light emitting device according to Modification 3 of the first embodiment. As shown in Fig. 9, the light emitting device 20C differs from the light emitting device 20 in the shape of the upper surface 26a of the first light-transmissive member 26. In the light emitting device 20, the upper surface 26a of the first light-transmissive member 26 is flat. In contrast, in the light emitting device 20C, the upper surface 26a of the first light-transmissive member 26 is concave.

[0057] In the light emitting device 20C, similarly to the light emitting device 20, light with a narrow light distribution can be emitted from the second surface 251b of the light-transmissive member 25. In addition, since the upper surface 26a of the first light-transmissive member 26 is concave, when the refractive index of the first light-transmissive member 26 is higher than the refractive index of the second light-transmissive member 27, the light entering the second light-transmissive member 27 from the first light-transmissive member 26 is refracted toward the center C1 at the interface between them, which can contribute to narrowing the light distribution.

[0058] Fig. 10 is a schematic cross-sectional view illustrating a light emitting device according to Modification 4 of the first embodiment. As shown in Fig. 10, the light emitting device 20D differs from the light emitting device 20 in that it has a third light-transmissive member 29. In the light emitting device 20D, the third light-transmissive member 29 containing a wavelength conversion material is disposed on the light emitting element 24, and the third light-transmissive member 29 is covered with the first light-transmissive member 26. In the light emitting device 20D, similar to the light emitting device 20, light with a narrow light distribution can be emitted from the second surface 251b of the light-transmissive member 25.

[0059] The first light-transmissive member 26 may or may not contain a wavelength conversion material. When the first light-transmissive member 26 contains a wavelength conversion material, the wavelength conversion material contained in the third light-transmissive member 29 may be the same as the wavelength conversion material contained in the first light-transmissive member 26, or may be a different material. When the wavelength conversion material contained in the third light-transmissive member 29 is the same as the wavelength conversion material contained in the first light-transmissive member 26, the concentration of the wavelength conversion material contained in the third light-transmissive member 29 can be made higher than the concentration of the wavelength conversion material contained in the first light-transmissive member 26. The light emitted from the upper surface of the light-emitting element 24 has a shorter distance to reach the upper surface of the first light-transmissive member 26 than the light emitted from the side surface of the light-emitting element 24, so less light is wavelength-converted. For this reason, the light emitted from the upper surface of the first light-transmissive member 26 may have color unevenness between directly above the light-emitting element 24 and other than directly above it. In contrast, with the above-described configuration, it is possible to increase the amount of light that is wavelength-converted out of the light emitted from the upper surface of the light emitting element 24. Therefore, it is possible to reduce color unevenness.

[0060] 11 is a schematic cross-sectional view illustrating a light emitting device according to Modification 5 of Embodiment 1. As shown in FIG. 11, the light emitting device 20E differs from the light emitting device 20 in that the light emitting device 20E has a protective film 30 disposed between the wall portion 23A and the light-transmitting member 25.

[0061] The protective film 30 is disposed so as to cover at least the upper surface 231 of the wall portion 23A. In the example of FIG. 11, the protective film 30 may cover the inner side surface 233 of the wall portion 23A, the bottom surface 21a of the recess 21x, and the light emitting element 24a in addition to the upper surface 231 of the wall portion 23A. Examples of materials for the protective film 30 include silicon oxide. When a protective film is provided on the outermost surfaces of the leads 22a and 22b, the protective film 30 can be formed, for example, by the same film formation method using the same material as the protective film provided on the outermost surfaces of the leads 22a and 22b.

[0062] In the light emitting device 20E, similarly to the light emitting device 20, light with a narrow light distribution can be emitted from the second surface 251b of the light-transmissive member 25. In addition, by disposing the protective film 30 between the wall portion 23A and the light-transmissive member 25, the adhesion between the wall portion 23A and the light-transmissive member 25 can be improved.

[0063] 12 is a schematic cross-sectional view illustrating a light emitting device according to Modification 6 of the first embodiment. As shown in FIG. 12, the light emitting device 20F is different from the light emitting device 20 in that the light emitting device 20F has a recess 231x that opens on the upper surface 231 of the wall portion 23A. In the light emitting device 20F, the upper surface 231 of the wall portion 23A is entirely flat and does not have an inclined surface. In the example shown in FIG. 12, the upper surface 231 of the wall portion 23A is parallel to the bottom surface 21a of the support 21.

[0064] The third surface 251c is located above the recess 231x. The recess 231x can be provided, for example, in a rectangular frame shape so as to surround the recess 21x in a plan view. The second light-transmissive member 27 is disposed inside the recess 231x.

[0065] In the light emitting device 20F, the recess 231x opening on the upper surface 231 of the wall portion 23A is provided, and the light emitted from the light emitting element 24 and reaching the third surface 251c is reflected by the third surface 251c and heads toward the recess 231x. The light that reaches the recess 231x is reflected in the recess 231x, so that the light heading from the recess 231x toward the first surface 251a side and / or the side surface 252 side of the translucent member 25 can be reduced. In addition, a part of the light reflected in the recess 231x can proceed toward the flat surface 251b1 side of the second surface 251b, so that the extraction efficiency of the light that is emitted from the second surface 251b can be increased. Therefore, similar to the light emitting device 20, light with a narrow light distribution can be emitted from the second surface 251b of the translucent member 25.

[0066] The shape of the recess 231x in cross-sectional view is, for example, a shape defined by two side surfaces and a bottom surface connecting the lower ends of the two side surfaces, or a shape defined only by two side surfaces. In cross-sectional view, the side surfaces defining the recess 231x may be perpendicular to the upper surface 231, or may be inclined. In addition, the side surfaces may be composed of only curved surfaces, or may be composed of surfaces including curved surfaces. The two side surfaces may have the same shape in cross-sectional view, or may have different shapes. The bottom surface defining the recess 231x may be a flat surface parallel to the upper surface 231, or may be a curved surface recessed toward the lead 22a side.

[0067] 12, the cross-sectional shape of the recess 231x is a shape (i.e., U-shaped) defined by side surfaces perpendicular to the upper surface 231 and a bottom surface recessed toward the leads 22a and 22b. In the cross-sectional view, the distance in the X direction between the upper ends of the side surfaces defining the recess 231x (i.e., the width of the recess 231x) is preferably from one to two times the width in the X direction of the third surface 251c, from the viewpoint of narrowing the light distribution and the strength of the resin member 23. In addition, in the cross-sectional view, the depth of the recess 231x is preferably from one-half the thickness of the wall portion 23A or less, from the viewpoint of the strength of the resin member 23.

[0068] [Surface light source 1] The above-mentioned light emitting devices can be arranged on a substrate to form a surface light source. Here, the surface light source will be described using the light emitting device 20 as an example. However, the light emitting device 20 may be replaced with any of the above-mentioned light emitting devices 20A to 20F.

[0069] Fig. 13 is a schematic top view illustrating the surface light source according to the first embodiment Fig. 14 is a schematic cross-sectional view taken along line XIV-XIV in Fig. 13 .

[0070] In the examples shown in Figs. 13 and 14, the surface light source 1 has a substrate 10 and a plurality of light emitting devices 20 arranged two-dimensionally. In the example shown in Fig. 13, the light emitting devices 20 in the surface light source 1 are arranged in a matrix on the substrate 10. Since the surface light source 1 has a plurality of light emitting devices 20 having a narrow light distribution characteristic, the surface light source 1 as a whole can also realize a narrow light distribution characteristic. Note that the light emitting devices are not limited to being arranged in a matrix on the substrate, and may be arranged in a staggered pattern. The components included in the surface light source 1 will be described in detail below.

[0071] (Substrate 10) The substrate 10 is a member on which a plurality of light emitting devices 20 are placed. In the example shown in Figs. 13 and 14, the substrate 10 has a base material 11, conductor wiring 15, and a covering member 18. The conductor wiring 15 is a member for supplying power to the light emitting devices 20, and is disposed on the upper surface of the base material 11. The covering member 18 covers, for example, a part of an area of ​​the conductor wiring 15 that is not electrically connected to the light emitting devices 20. The covering member 18 has an opening 18x, and the light emitting devices 20 are disposed in the opening 18x.

[0072] The material of the base material 11 may be any material capable of insulating and isolating at least one pair of conductor wirings 15, and examples of such materials include ceramics, resins, composite materials, etc. Examples of resins include phenolic resins, epoxy resins, polyimide resins, BT resins, polyphthalamide (PPA), and polyethylene terephthalate (PET). Examples of composite materials include the above-mentioned resins mixed with inorganic fillers such as glass fiber, silicon oxide, titanium oxide, and aluminum oxide, glass fiber reinforced resins (glass epoxy), and metal substrates in which a metal member is coated with an insulating layer.

[0073] The thickness of the substrate 11 can be appropriately selected. The substrate 11 may be either a flexible substrate that can be manufactured by a roll-to-roll process or a rigid substrate. The rigid substrate may be a bendable thin rigid substrate.

[0074] The material of the conductor wiring 15 is not particularly limited as long as it is a conductive member, and it is possible to use a material that is usually used as a wiring layer of a circuit board, etc. As the material of the conductor wiring 15, for example, copper can be used.

[0075] The covering member 18 is insulating. Examples of materials for the covering member 18 include the same materials as those exemplified as the materials for the base material 11. The covering member 18 may be the above-mentioned resin containing a white light-reflective filler such as titanium oxide, aluminum oxide, silicon oxide, etc. and / or a large number of air bubbles. This allows the light emitted from the light-emitting device 20 to be reflected by the covering member 18, thereby improving the light extraction efficiency of the surface light source 1.

[0076] Fig. 15 is a schematic partial cross-sectional view illustrating a surface light source including a partition member. As shown in Fig. 15, the surface light source 1 can have a partition member 13. The partition member 13 can reflect light that is emitted to the outside from the second inclined surface 251b2 of the second light-transmissive member 27 of the light-emitting device 20 and reaches the partition member 13 upward.

[0077] The partitioning member 13 is disposed on the same side of the substrate 10 as the light emitting devices 20. The partitioning member 13 includes a top 13a arranged in a lattice pattern in a plan view, a wall 13b surrounding each of the light emitting devices 20 in a plan view, and a bottom 13c connected to the lower end of the wall 13b, and has a plurality of regions surrounding the light emitting devices 20. The wall 13b of the partitioning member 13 extends, for example, from the top 13a toward the substrate 10, and in a cross-sectional view, the width of the region surrounded by the opposing wall 13b becomes narrower toward the substrate 10 side. In the example shown in FIG. 15, one light emitting device 20 is disposed in one partition surrounded by the wall 13b. However, two or more light emitting devices 20 may be disposed in one partition.

[0078] The partitioning member 13 is preferably light reflective. This allows the light emitted from the light emitting device 20 to be efficiently reflected upward by the partitioning member 13. In this case, the partitioning member 13 may be molded using a resin containing a light reflective filler such as titanium oxide, aluminum oxide, silicon oxide, etc. and / or a large number of bubbles, or may be molded using a resin that does not contain a reflecting material and then provided with a reflecting material on the surface. When the partitioning member 13 contains a resin containing a large number of bubbles, light is reflected at the interface between the bubbles and the resin. In addition, examples of the resin used for the partitioning member 13 include thermoplastic resins such as acrylic resin, polycarbonate resin, cyclic polyolefin resin, polyethylene terephthalate, polyethylene naphthalate, and polyester, and thermosetting resins such as epoxy resin and silicone resin. The partitioning member 13 is preferably set so that the reflectance of the light emitted from the light emitting device 20 is 70% or more.

[0079] In the above example, the surface light source 1 is described as including the substrate 10. However, the present invention is not limited to this, and the substrate 10 can be provided as necessary and can be omitted. For example, the surface light source 1 can have a structure in which a plurality of light emitting devices 20 are integrally held by a light-transmitting resin or the like.

[0080] Furthermore, the surface light source 1 may include an optical member disposed above the light emitting device 20 with the partition member 13 interposed therebetween. The optical sheet is, for example, a diffusion sheet. Providing the surface light source 1 with a diffusion sheet can improve the uniformity of the light extracted from the surface light source 1 to the outside. Furthermore, the surface light source 1 may further include at least one selected from the group consisting of a first prism sheet, a second prism sheet, and a polarizing sheet above the diffusion sheet. Providing the surface light source 1 with one or more of these optical members can further improve the uniformity of the light.

[0081] Second Embodiment In the second embodiment, an example of a liquid crystal display device (liquid crystal display device) using a surface light source 1 as a backlight light source will be described.

[0082] Fig. 16 is a configuration diagram illustrating a liquid crystal display device according to the second embodiment. As shown in Fig. 16, the liquid crystal display device 1000 includes, from the top, a liquid crystal panel 720, an optical member 710, and a surface light source 1. The surface light source 1 may include, as an optical member, a diffusion plate, a first prism sheet, a second prism sheet, and a DBEF (reflective polarizing sheet) stacked above the light emitting device 20, for example, from the surface light source 1 side.

[0083] The liquid crystal display device 1000 is a so-called direct type liquid crystal display device in which a surface light source 1 is laminated below a liquid crystal panel 720. The liquid crystal display device 1000 irradiates the liquid crystal panel 720 with light emitted from the surface light source 1.

[0084] From the viewpoint of making the surface light source 1 thinner, the thickness of the surface light source 1 can be set to 15 mm or less. This makes the surface light source 1 thinner, and the liquid crystal display device 1000 can be made thinner.

[0085] The surface light source 1 can be used as a backlight for the liquid crystal display device 1000 in televisions, tablets, smartphones, smart watches, head-up displays, digital signage, bulletin boards, etc. The surface light source 1 can also be used as a light source for lighting, and can be used for emergency lighting, line lighting, various types of illumination, in-vehicle instrument panels, etc.

[0086] The above describes the preferred embodiments, etc. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments, etc. without departing from the scope of the claims.

[0087] In addition to the above-described embodiment, the following supplementary notes are further disclosed. (Appendix 1) A support having a recess defined by a wall portion and a bottom surface surrounded by the wall portion; A light emitting element placed on the bottom surface; a light-transmitting member disposed on the wall portion and the light-emitting element, The upper surface of the light-transmitting member is The first page and a second surface that is surrounded by the first surface in a plan view and that is convex upward relative to the first surface in a cross-sectional view; a curved third surface connecting the first surface and the second surface in a cross-sectional view, The upper surface of the wall portion has a first inclined surface inclined with respect to the bottom surface, The third surface is located above the first inclined surface. (Appendix 2) 2. The light emitting device of claim 1, wherein the second surface includes a plane located above the light emitting element. (Appendix 3) 3. The light emitting device of claim 2, wherein the second surface includes a second inclined surface and a curved surface connecting the second inclined surface and the flat surface. (Appendix 4) 4. The light emitting device according to claim 1, wherein the second surface is circular in a plan view. (Appendix 5) 4. The light emitting device according to claim 1, wherein the second surface is a rectangle with curved corners in a plan view. (Appendix 6) 6. The light emitting device according to claim 1, wherein, in a plan view, a center of the light emitting element is different from a center of the bottom surface and coincides with a center of the second surface. (Appendix 7) The light-transmitting member includes a first light-transmitting member disposed in the recess and including a wavelength converting material; 7. The light emitting device according to claim 1, further comprising: a second translucent member disposed on the first translucent member and the wall portion, the second translucent member not including the wavelength converting material. (Appendix 8) 8. The light emitting device according to claim 7, wherein an upper surface of the first light-transmissive member is concave. (Appendix 9) a third light-transmissive member including a wavelength converting material is disposed on the light-emitting element; 9. The light emitting device according to claim 7 or 8, wherein the third light-transmissive member is covered with the first light-transmissive member. (Appendix 10) 10. The light emitting device according to claim 1, further comprising a protective film disposed between the wall portion and the light-transmitting member. (Appendix 11) A surface light source in which the light emitting device according to any one of claims 1 to 10 is arranged in two dimensions. (Appendix 12) A liquid crystal display device using the surface light source according to claim 11 as a backlight light source. [Explanation of symbols]

[0088] 1 Planar light source 10 Substrate 11 Base material 13 Partitioning materials 13a top 13b Wall section 13c bottom 15 Conductor wiring 18 Covering materials 18x opening 20, 20A, 20B, 20C, 20D, 20E, 20F Light-emitting device 21 Support 21a Bottom 21x recess 21y groove 22a, 22b Lead 23 Resin parts 23A Wall section 23B Holding part 24, 24a, 24b Light-emitting element 25 Translucent material 26 First translucent member 26a Top side 27 Second translucent member 28a, 28b, 28c Wire 29 Third translucent member 30 Protective film 231 Top surface 231a 1st slope 231b,231c plane 231x recess 232 External surface 233 Inner surface 251 Top surface 252 Side 251a 1st page 251b 2nd page 251c 3rd page 251b1 plane 251b2 2nd slope 251b3 Curved surface 252 Side 710 Optical components 720 LCD Panel 1000 Liquid crystal display device

Claims

1. A support having a recess defined by a wall portion and a bottom surface surrounded by the wall portion; A light emitting element placed on the bottom surface; a light-transmitting member disposed on the wall portion and the light-emitting element, The upper surface of the light-transmitting member is The first page and a second surface that is surrounded by the first surface in a plan view and that is convex upward relative to the first surface in a cross-sectional view; a curved third surface connecting the first surface and the second surface in a cross-sectional view, The upper surface of the wall portion has a first inclined surface inclined with respect to the bottom surface, The third surface is located above the first inclined surface.

2. The light emitting device according to claim 1 , wherein the second surface includes a plane located above the light emitting element.

3. The light emitting device according to claim 2 , wherein the second surface includes a second inclined surface and a curved surface connecting the second inclined surface and the flat surface.

4. The light emitting device according to claim 1 , wherein the second surface is circular in a plan view.

5. The light emitting device according to claim 1 , wherein the second surface has a rectangular shape with curved corners in a plan view.

6. The light emitting device according to claim 1 , wherein a center of the light emitting element is different from a center of the bottom surface and coincides with a center of the second surface in a plan view.

7. The light-transmitting member includes a first light-transmitting member disposed in the recess and including a wavelength converting material; The light emitting device according to claim 1 , further comprising: a second translucent member that is disposed on the first translucent member and the wall portion and does not contain the wavelength converting material.

8. The light emitting device according to claim 7 , wherein an upper surface of the first light-transmissive member is concave.

9. a third light-transmissive member including a wavelength converting material is disposed on the light-emitting element; The light emitting device according to claim 7 , wherein the third light transmissive member is covered by the first light transmissive member.

10. The light emitting device according to claim 1 , further comprising a protective film disposed between the wall portion and the light-transmitting member.

11. A surface light source comprising the light emitting device according to claim 1 arranged two-dimensionally.

12. A liquid crystal display device using the surface light source according to claim 11 as a backlight source.

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