Patent Publication Number: US-11646298-B2

Title: Light-emitting device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of copending application Ser. No. 16/457,412, filed on Jun. 28, 2019, which claims priority under 35 U.S.C. § 119(a) to Application No. 2018-124179, filed in Japan on Jun. 29, 2018, all of which are hereby expressly incorporated by reference into the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a light-emitting device. 
     2. Description of Related Art 
     Light-emitting devices each including a plurality of light sources have been proposed (see WO 2012/023459). 
     In a conventional light-emitting device, the luminance at an outer peripheral portion of the device may be lower than the luminance at the central portion of the device. This is because light emitted from other portions of the device easily reaches the central portion of the device but does not easily reach the outer peripheral portion of the device. 
     SUMMARY OF THE INVENTION 
     The above problem can be solved by, for example, the following. 
     A light-emitting device includes a base member, conductor wiring disposed on an upper surface of the base member, a reflective member covering the upper surface of the base member and an upper surface of the conductor wiring and having a plurality of apertures in which part of the upper surface of the base member and part of the upper surface of the conductor wiring are located, a plurality of light sources bonded to the part of the upper surface of the conductor wiring located in the plurality of apertures with bonding members, and a reflector that is disposed on the reflective member and includes a plurality of surrounding portions, the plurality of surrounding portions respectively surrounding the plurality of light sources in a plan view, each of the plurality of surrounding portions having inclined lateral surfaces that widen in an upward direction, the plurality of surrounding portions including a plurality of first surrounding portions and a plurality of second surrounding portions surrounding the plurality of first surrounding portions, an area of an aperture in each of the plurality of second surrounding portions being smaller than an area of an aperture in each of the plurality of first surrounding portions in the plan view. 
     Effects of the Invention 
     In the light-emitting device as described above, the light density over the surrounding portions at the outer peripheral portion of the device is higher than the light density over the surrounding portions at the central portion of the device. Accordingly, the luminance at the outer peripheral portion of the device can be similar to the luminance at the central portion of the device, so that the luminance over the device can be more uniform throughout the device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a schematic plan view of a light-emitting device according to a first embodiment. 
         FIG.  1 B  is a diagram in which a plurality of first surrounding portions in  FIG.  1 A  are shaded in gray. 
         FIG.  1 C  is a diagram in which a plurality of second surrounding portions in  FIG.  1 A  are shaded in gray. 
         FIG.  1 D  is a schematic cross-sectional view taken along the line  1 D- 1 D of  FIG.  1 A . 
         FIG.  1 E  is a schematic, partial, enlarged view of  FIG.  1 D . 
         FIG.  1 F  is a schematic, partial, enlarged view of  FIG.  1 E . 
         FIG.  2 A  is a schematic cross-sectional view of another example of a light source in the first embodiment. 
         FIG.  2 B  is a schematic cross-sectional view of still another example of a light source in the first embodiment. 
         FIG.  3    is a schematic cross-sectional view of another example of a reflector in the first embodiment. 
         FIG.  4 A  is a diagram in which apertures of a reflective member in a first surrounding portion and a second surrounding portion in a schematic, partial, enlarged view of  FIG.  1 A  are shaded in gray. 
         FIG.  4 B  is a schematic cross-sectional view of still another example of a reflector in the first embodiment. 
         FIG.  5 A  is a schematic plan view of a light-emitting device according to a second embodiment. 
         FIG.  5 B  is a diagram in which a plurality of first surrounding portions in  FIG.  5 A  are shaded in gray. 
         FIG.  5 C  is a diagram in which a plurality of second surrounding portions in  FIG.  5 A  are shaded in gray. 
         FIG.  5 D  is a diagram in which a plurality of third surrounding portions in  FIG.  5 A  are shaded in gray. 
         FIG.  5 E  is a schematic cross-sectional view taken along the line  5 E- 5 E of  FIG.  5 A . 
         FIG.  5 F  is a diagram in which apertures of a reflective member in a first surrounding portion, a second surrounding portion, and a third surrounding portion in a schematic, partial, enlarged view of  FIG.  5 A  are shaded in gray. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Light-Emitting Device  1  According to First Embodiment 
       FIG.  1 A  is a schematic plan view of a light-emitting device according to a first embodiment.  FIG.  1 B  is a diagram in which a plurality of first surrounding portions  32  in  FIG.  1 A  are shaded in gray to facilitate the understanding of the locations of the first surrounding portions  32 .  FIG.  1 C  is a diagram in which a plurality of second surrounding portions  34  in  FIG.  1 A  are shaded in gray to facilitate the understanding of the locations of the second surrounding portions  34 . In  FIG.  1 A ,  FIG.  1 B , and  FIG.  1 C , only a base member  10 , a reflective member  70 , light-emitting elements  22 , and a reflector  30  are illustrated, and illustrations of other members such as an optical member  40  are omitted, to facilitate the understanding of the shape of the reflector  30 .  FIG.  1 D  is a schematic cross-sectional view taken along the line  1 D- 1 D of  FIG.  1 A .  FIG.  1 E  is a schematic, partial, enlarged view of  FIG.  1 D .  FIG.  1 F  is a schematic, partial, enlarged view of  FIG.  1 E . 
     As shown in  FIG.  1 A  to  FIG.  1 F , a light-emitting device  1  according to the first embodiment includes the base member  10 , conductor wiring  50  disposed on an upper surface of the base member  10 , the reflective member  70  covering the upper surface of the base member  10  and an upper surface of the conductor wiring  50  and having a plurality of apertures in which part of the upper surface of the base member  10  and part of the upper surface of the conductor wiring  50  are located, a plurality of light sources  20  bonded to the part of the upper surface of the conductor wiring  50  located in the plurality of apertures with bonding members  60 , and the reflector  30  that is disposed on the reflective member  70  and includes a plurality of surrounding portions. The plurality of surrounding portions respectively surround the plurality of light sources  20  in a plan view. Each of the plurality of surrounding portions has inclined lateral surfaces X widened upward. The plurality of surrounding portions include the plurality of first surrounding portions  32  and the plurality of second surrounding portions  34  surrounding the plurality of first surrounding portions  32 . An area of an aperture S 8  in each of the plurality of second surrounding portions  34  is smaller than an area of an aperture S 7  in each of the plurality of first surrounding portions  32  in the plan view. The details will be described below. 
     (Light-Emitting Device  1 ) 
     The light-emitting device  1  is, for example, a direct-lit backlight device. 
     (Base Member  10 ) 
     The base member  10  is a member on or above which the light sources  20  are mounted. 
     Examples of a material used for the base member  10  include ceramics and resins, such as phenolic resins, epoxy resins, polyimide resins, BT resins, polyphthalamide (PPA), and poly(ethylene terephthalate) (PET). Examples of the ceramics include alumina, mullite, forsterite, glass ceramics, and nitride (such as AlN) and carbide (such as SiC) ceramics, and LTCC. In the case where a resin is used as a material of the base member  10 , glass fiber or an inorganic filler, such as SiO 2 , TiO 2 , or Al 2 O 3 , can be mixed into the resin to improve the mechanical strength, reduce the thermal expansion coefficient, and improve the light reflectance. A metal substrate in which an insulating layer is disposed on a surface of a metal member may be used as the base member  10 . 
     A thickness of the base member  10  can be selected appropriately. The base member  10  may be, for example, a flexible substrate that can be manufactured using a roll-to-roll manner, or may be a rigid substrate. The rigid substrate may be a slim rigid substrate that is bendable. 
     (Conductor Wiring  50 ) 
     The conductor wiring  50  for supplying electricity to the light sources  20  (i.e., light-emitting elements  22 ) can be disposed at least on an upper surface of the base member  10 . The conductor wiring  50  is electrically connected to electrodes of the light sources  20  (i.e., light-emitting elements  22 ) and is configured to supply a current (i.e., electricity) from outside. 
     A material of the conductor wiring  50  can be appropriately selected in accordance with a material used for the base member  10  and a method of manufacturing the base member  10 . For example, in the case where a ceramic is used as a material of the base member  10 , a material of the conductor wiring  50  is preferably a material having a melting point that is high enough to endure sintering temperatures of a ceramic sheet. A metal with a high melting point, such as tungsten or molybdenum, is preferable for a material of the conductor wiring  50 . In addition, a member in which a surface of a metal member made of such a metal is covered with another metal material, such as nickel, gold, or silver, by plating, sputtering, vapor deposition, or the like can be used as the conductor wiring  50 . In the case where a glass epoxy resin is used as a material of the base member  10 , a material that is easy to process is preferably used as a material of the conductor wiring  50 . 
     The conductor wiring  50  can be formed on one or both of opposite surfaces of the base member  10  by a method such as vapor deposition, sputtering, or plating. Metal foil attached to the base member  10  by pressing may serve as the conductor wiring  50 . The conductor wiring  50  can be patterned to have a predetermined shape by forming a mask on the conductor wiring  50  by printing or photolithography and then performing etching. 
     (Reflective Member  70 ) 
     The reflective member  70  is an insulating member that reflects light or reduces leakage and absorption of light to increase light extraction efficiency of the light-emitting device  1 . The reflective member  70  covers the upper surface of the base member  10  and the upper surface of the conductor wiring  50 . For example, a member containing a white filler can be used as the reflective member  70 . For the reflective member  70 , any appropriate insulating material can be used, and a material that is unlikely to absorb light emitted from the light-emitting elements  22  is particularly preferable. Specific examples of the material used for the reflective member  70  include an epoxy resin, a silicone resin, a modified silicone resin, a urethane resin, an oxetane resin, an acrylic resin, a polycarbonate resin, and a polyimide resin. 
     The reflective member  70  has a plurality of apertures S 7  and S 8  in which part of the upper surface of the base member  10  and part of the upper surface of the conductor wiring  50  are located. For example, as shown in  FIG.  4 A  and  FIG.  4 B , the area of the aperture S 8  in each of the second surrounding portions  34  is smaller than the area of the aperture S 7  in each of the first surrounding portions  32  in a plan view. With this structure, the reflective member  70  reflects more light in the second surrounding portions  34  than in the first surrounding portions  32 , so that the light density over the surrounding portions at the outer peripheral portion of the light-emitting device is higher than the light density over the surrounding portions at the central portion of the device. Accordingly, a luminance at the outer peripheral portion of the device can be similar to a luminance at the central portion of the device, so that the luminance over the device can be more uniform throughout the device. 
     (Light Sources  20 ) 
     The plurality of light sources  20  are bonded to the part of the upper surface of the conductor wiring  50  located in the plurality of apertures S 7  and S 8  with the bonding members  60 . 
     The intervals between the light sources  20 , in other words, intervals P between adjacent light sources  20 , are preferably uniform (including the case where the intervals P are varied to the extent that is small enough to be regarded as uniform) in the longitudinal and lateral directions in a plan view. In the present embodiment, the area of the aperture S 8  in each of the second surrounding portions  34  is smaller than the aperture area S 7  of each of the first surrounding portions  32 . A luminance similar to the luminance at the central portion of the light-emitting device can be obtained at the outer peripheral portion of the device without comparatively complicated design changes such as changes in the arrangement of the light sources  20 . Thus, designing of the light-emitting device  1  is facilitated. In addition to employing different sizes of the aperture areas S 7  and S 8  of the reflective member  70 , by employing the first surrounding portions  32  that differ in size from the second surrounding portions  34  of the reflector  30 , such as by allowing an upper aperture area S 2  defined by the upper ends of the inclined lateral surfaces X of each of the second surrounding portions  34  to be smaller than an upper aperture area S 1  defined by the upper ends of the inclined lateral surfaces X of each of the first surrounding portions  32 , a luminance similar to the luminance at the central portion of the device is more easily obtained at the outer peripheral portion of the device. Thus, the need for changes in the arrangement of the light sources  20  is further reduced, and design flexibility of the light-emitting device  1  can be more easily ensured. 
     Each light source  20  may include the light-emitting element  22  such as a light-emitting diode. The light-emitting element  22  includes, for example, a light-transmissive substrate and a semiconductor layer layered on the substrate. For example, sapphire can be used for the light-transmissive substrate. The semiconductor layer includes, for example, an n-type semiconductor layer, an active layer, and a p-type semiconductor layer in this order from the substrate. For example, ZnSe, a nitride semiconductor (InxAl y Ga 1-x-y N, where 0≤X, 0≤Y, and X+Y≤1), GaP, GaAlAs, or AlInGaP can be used for the semiconductor layer. For example, an n-side electrode is formed on the n-type semiconductor layer, and a p-side electrode is formed on the p-type semiconductor layer. 
     Each light source  20  may include a sealing member  26 . The sealing member  26  protects the light-emitting element  22  against external environments and optically controls light that exits from the light-emitting element  22 . The sealing member  26  is disposed on or above the base member  10  to cover the light-emitting element  22 . An end portion of each of the apertures S 7  and S 8  of the reflective member  70 , the end portion facing the light source, may be located inside or outside the sealing member  26  in a plan view. In the case where the end portion facing the light source is located inside the sealing member  26 , each of the apertures S 7  and S 8  is covered with the sealing member  26 . In the case where the end portion facing the light source is located outside the sealing member  26 , the sealing member  26  is disposed inside each of the apertures S 7  and S 8 . 
     Examples of the material used for the sealing member  26  include an epoxy resin, a silicone resin, a mixture of these resins, and a light-transmissive material such as glass. Among these materials, a silicone resin is preferably selected in consideration of light resistance and ease of molding. The sealing member  26  can contain a light-diffusing agent, a wavelength conversion member, such as a phosphor, that absorbs light emitted from the light-emitting element  22  to emit light with a wavelength different from the wavelength of the light emitted from the light-emitting element  22 , and a coloring agent corresponding to the emission color of the light-emitting element  22 . 
     The sealing member  26  can be formed by, for example, molding such as compression molding or injection molding, dropping, or drawing. Alternatively, by optimizing the viscosity of a material of the sealing member  26 , the shape of the sealing member  26  can be controlled due to surface tension of the material of the sealing member  26 . In the case of dropping or drawing, the sealing member  26  can be formed in a simpler manner without using molds. Adjustment of the viscosity may be achieved by employing a material having a desired viscosity as a material of the sealing member  26 , or by using the above-described light-diffusing agent, wavelength conversion member, or coloring agent. 
     Each light source  20  preferably has a batwing light distribution characteristic. In such a light distribution characteristic, the amount of light emitted directly upward from each light source  20  can be reduced, and a broad light distribution of the light source  20  can be achieved. Accordingly, the thickness of the light-emitting device  1  can be reduced, particularly in the case where the light-transmissive optical member  40  is disposed to face the base member  10 . Thus, a light-emitting device with a small thickness can be provided while allowing the luminance at the outer peripheral portion of the device to be the same as the luminance at the central portion of the device. 
     The expression “batwing light distribution characteristic” refers to such a light distribution characteristic that the luminance at the central portion is lower than the luminance at the outer peripheral portion. Examples of the batwing light distribution characteristic include, with an optical axis L being 0 degrees, a light distribution characteristic having an emission intensity distribution in which the emission intensity at angles with absolute values larger than 0 degrees is high and a light distribution characteristic having an emission intensity distribution in which the emission intensity is the highest in a range of approximately 45 degrees to 90 degrees. 
     Each light source  20  may include a reflective layer  28  on the upper surface of the light-emitting element  22 . In this case, the sealing member  26  can cover, for example, the light-emitting element  22  and the reflective layer  28 . With the sealing member  26  disposed in this manner, forming the sealing member  26  into a shape such as a shape described below shown in  FIG.  2 A  easily provides the batwing light distribution characteristic. 
       FIG.  2 A  is a schematic cross-sectional view of another example of a light source in the first embodiment. A sealing member  26  may have, for example, a domical shape or, as shown in  FIG.  2 A , a shape that broadens the distribution of light emitted from the light-emitting element  22 , more specifically, a shape having a depressed portion directly above the light-emitting element. With this structure, the sealing member  26  functions as a lens to broaden the light distribution, and the batwing light distribution characteristic can be obtained without the reflective layer  28  as described above. Alternatively, the combination of the reflective layer  28  and the sealing member  26  that functions as a lens can more easily provide the batwing light distribution characteristic. 
       FIG.  2 B  is a schematic cross-sectional view of still another example of a light source in the first embodiment. Each light source  20  may include a reflective layer  28  over a sealing member  26  as shown in  FIG.  2 B . With this structure, the reflective layer  28  reflects light emitted upward from the light-emitting element  22 , so that the amount of light emitted directly upward from the light-emitting element  22  is reduced. Accordingly, the batwing light distribution characteristic can be easily achieved. 
     The reflective layer  28  may be a metal film or a dielectric multilayer film. 
     It is preferable that the light sources  20  can be driven separately from one another. It is particularly preferable that light control (such as local dimming and high dynamic range: HDR) can be performed with respect to each of the light sources  20 . 
     (Reflector  30 ) 
     The reflector  30  reflects light emitted from the light sources  20 . The reflector  30  preferably has an average reflectance of 70% or more of light emitted from the light sources  20  in a wavelength range of 440 nm to 630 nm. For example, a resin member containing a reflective material made of particles of a metal oxide such as titanium oxide, aluminum oxide, or silicon oxide, or a member in which a reflective member is disposed on a surface of a resin member containing no reflective material can be used for the reflector  30 . 
     The reflector  30  is disposed on the reflective member  70  and includes a plurality of surrounding portions, which respectively surround the plurality of light sources  20  in a plan view. A single surrounding portion surrounds a single light source. The plurality of surrounding portions include the first surrounding portions  32  and the second surrounding portions  34  surrounding the first surrounding portions  32 . Each of the plurality of surrounding portions has the inclined lateral surfaces X widened upward. The upper aperture area S 2  defined by the upper ends of the inclined lateral surfaces X of each of the second surrounding portions  34  is preferably smaller than the upper aperture area S 1  defined by the upper ends of the inclined lateral surfaces X of each of the first surrounding portions  32 . This structure allows the light density over the second surrounding portions  34  to be even higher than the light density over the first surrounding portions  32 ; in other words, this structure allows the light density at the outer peripheral portion of the light-emitting device to be higher than the light density over the central portion of the device. A luminance similar to the luminance at the central portion of the device is thus more easily obtained at the outer peripheral portion of the device. The “light density” refers to the degree of intensity of light per unit area. 
     The reflector  30  has a thickness T in a range of, for example, 100 μm to 300 μm. 
     The plurality of surrounding portions of the reflector  30  each preferably have a planar portion extending from the lower ends of the inclined lateral surfaces X toward the light source  20 . In  FIG.  1 E , the inclination angle of each of the inclined lateral surfaces X of the second surrounding portions  34  is larger than the inclination angle of each of the inclined lateral surfaces X of the first surrounding portions  32 . 
     A distance D 2  between an end portion of the planar portion of the second surrounding portions  34 , the end portion facing a corresponding one of the light sources, and an end portion of the corresponding light source is preferably smaller than a distance D 1  between an end portion of the planar portion of the first surrounding portions  32 , the end portion facing a corresponding one of the light sources, and an end portion of the corresponding light source as shown in, for example,  FIG.  4 B . This structure allows the light density over the second surrounding portions  34  to be even higher than the light density over the first surrounding portions  32 , so that the light density over the surrounding portions at the outer peripheral portion of the light-emitting device is higher than the light density over the surrounding portions at the central portion of the device. Thus, a luminance similar to the luminance at the central portion of the device is more easily obtained at the outer peripheral portion of the device. 
       FIG.  3    is a schematic cross-sectional view of another example of a reflector in the first embodiment. A height H 2  between the upper surface of the base member  10  and the upper end of each of the inclined lateral surfaces X of the second surrounding portions  34  is preferably greater than a height H 1  between the upper surface of the base member  10  and the upper end of each of the inclined lateral surfaces X of the first surrounding portions  32  as shown in  FIG.  3   . This structure increases the amount of light that is multiple-reflected within the second surrounding portions  34 , which further increases the light density over the second surrounding portions  34 , so that the luminance at the outer peripheral portion of the light-emitting device can be increased. 
     (Optical Member  40 ) 
     The optical member  40  faces the base member  10  across a plurality of light sources  20 . A distance K 2  between the upper end of each of the inclined lateral surfaces X and the optical member  40  is preferably equal to or less than a half of a distance K 1  between the upper surface of the base member  10  and the upper end of each of the inclined lateral surfaces X. This structure allows a depth of each of the first surrounding portions  32  and the second surrounding portions  34  to be relatively great in proportion to the distance between the reflector  30  and the optical member  40 , so that the number of repetitions of multiple reflection of light within the first surrounding portions  32  and the second surrounding portions  34  can be increased. Accordingly, the density of light from each surrounding portion at the location of the optical member  40  can be enhanced. 
     For example, a light-transmissive member such as a semitransparent mirror can be used for the optical member  40 . For the semitransparent mirror, for example, a material that reflects a part of incident light and transmits another part of the light can be used. 
     The semitransparent mirror preferably has a reflectance with respect to light incident in an oblique direction lower than a reflectance thereof with respect to light incident in a perpendicular direction. That is, the semitransparent mirror preferably has a property in which a reflectance of the semitransparent mirror with respect to light emitted from each light source  20  parallel to the optical axis direction is high and a light reflectance decreases in accordance with increase in the radiation angle (in other words, the property in which the amount of light transmitted through the semitransparent mirror increases). Light parallel to the optical axis direction is regarded to have a radiation angle of 0 degrees. This structure can easily provide a uniform luminance distribution when the semitransparent mirror is observed from the emission surface. 
     For example, a dielectric multilayer film can be used for the semitransparent mirror. By using a dielectric multilayer film, a reflective film with low light absorption can be obtained. Further, the reflectance can be adjusted as desired by changing the design of the film, and the reflectance with respect to an angle of emitted light can be controlled. For example, with the dielectric multilayer film designed to have a reflectance with respect to light incident in an oblique direction on the semitransparent mirror lower than a reflectance thereof with respect to light incident perpendicularly on the semitransparent mirror, a property can be easily realized in which a reflectance with respect to light incident perpendicularly on the light-extracting surface is higher and a reflectance decreases in accordance with increase in the angle of incident light with respect to the light-extracting surface. 
     The light-emitting device  1  may include a light diffusing plate at the emission surface of the optical member  40 . The light diffusing plate diffuses light emitted from a plurality of light sources  20  to reduce unevenness in luminance. For the light diffusing plate, a material that is unlikely to absorb visible light, such as a polycarbonate resin, a polystyrene resin, an acrylic resin, or a polyethylene resin can be used. For example, a member that contains a base material and a material having a refractive index different from the refractive index of the base material, or a member made of a base material and having a surface that is processed so as to scatter light can be used for the light diffusing plate. 
     (Bonding Members  60 ) 
     The light-emitting device  1  includes the bonding members  60 . The bonding members  60  fix the light sources  20  to the base member  10  and/or the conductor wiring  50 . Examples of the bonding members  60  include insulating resins and electrically-conductive members. In the case where the light sources  20  are flip-chip mounted, electrically-conductive members can be used for the bonding members  60 . Examples of the bonding members  60  include Au-containing alloys, Ag-containing alloys, Pd-containing alloys, In-containing alloys, Pb—Pd-containing alloys, Au—Ga-containing alloys, Au—Sn-containing alloys, Sn-containing alloys, Sn—Cu-containing alloys, Sn—Cu—Ag-containing alloys, Au—Ge-containing alloys, Au—Si-containing alloys, Al-containing alloys, Cu—In-containing alloys, and mixtures of metals and fluxes. 
     For example, a member in a form of liquid, paste, or solid (sheet-shaped, block-shaped, powdered, or wire-shaped) may be used singly or in combination for the bonding members  60 . Appropriate materials can be selected in accordance with the shape of the base member  10  and the composition. In the case where electrically connecting the light sources  20  to the conductor wiring  50  and mounting or fixing the light sources  20  above or to the base member  10  are not performed at once but are performed separately, wires other than the bonding members  60  may be used to electrically connect the light sources to the conductor wiring  50 . 
     As described above, in the light-emitting device  1  according to the first embodiment, the area of the aperture S 8  in each of the second surrounding portions  34  is smaller than the area of the aperture S 7  in each of the first surrounding portions  32  in a plan view. Thus, the reflective member  70  reflects more light in the second surrounding portions  34  than in the first surrounding portions  32 , so that the light density over the surrounding portions at the outer peripheral portion of the device is higher than the light density over the surrounding portions at the central portion of the device. Accordingly, a luminance at the outer peripheral portion of the device can be similar to a luminance at the central portion of the device, so that the luminance over the device can be more uniform throughout the device. 
     Light-Emitting Device  2  According to Second Embodiment 
       FIG.  5 A  is a schematic plan view of a light-emitting device according to a second embodiment.  FIG.  5 B  is a diagram in which the plurality of first surrounding portions  32  in  FIG.  5 A  are shaded in gray to facilitate the understanding of the locations of the first surrounding portions  32 .  FIG.  5 C  is a diagram in which the plurality of second surrounding portions  34  in  FIG.  5 A  are shaded in gray to facilitate the understanding of the locations of the second surrounding portions  34 .  FIG.  5 D  is a diagram in which a plurality of third surrounding portions  36  in  FIG.  5 A  are shaded in gray to facilitate the understanding of the locations of the third surrounding portions  36 .  FIG.  5 E  is a schematic cross-sectional view taken along the line  5 E- 5 E of  FIG.  5 A .  FIG.  5 F  is a diagram in which apertures of a reflective member in a first surrounding portion, a second surrounding portion, and a third surrounding portion in a schematic, partial, enlarged view of  FIG.  5 A  are shaded in gray. 
     As shown in  FIG.  5 A  to  FIG.  5 F , a light-emitting device  2  according to the second embodiment differs from the light-emitting device  1  according to the first embodiment in that the plurality of surrounding portions include the third surrounding portions  36  between the first surrounding portions  32  and the second surrounding portions  34 , and in that the area of an aperture S 9  in each of the third surrounding portions  36  is smaller than the area of the aperture S 7  in each of the first surrounding portions  32  and larger than the area of the aperture S 8  in each of the second surrounding portions  34  in a plan view. In the light-emitting device  2  according to the second embodiment, the relation the light density over the second surrounding portions  34 &gt;the light density over the third surrounding portions  36 &gt;the light density over the first surrounding portions  32  is satisfied, and the light density over the device gradually increases from the central portion toward the outer peripheral portion of the device. Accordingly, the luminance at the outer peripheral portion of the device can be similar to the luminance at the central portion of the device, so that the luminance over the device can be more uniform throughout the device. It is preferable that an upper aperture area S 3  defined by the upper ends of the inclined lateral surfaces X of each of the third surrounding portions  36  be smaller than the upper aperture area S 1  in each of the first surrounding portions  32  and larger than the upper aperture area S 2  in each of the second surrounding portions  34 . This structure further facilitates establishment of the relation between the light densities described above. Thus, a luminance similar to the luminance at the central portion of the device can be obtained at the outer peripheral portion of the device, so that the luminance over the device can be even more uniform throughout the device. 
     Certain embodiments of the present invention have been described above, but descriptions thereof do not limit the scope of in the claims.