Light-emitting device

Abstract

To provide a light-emitting device in which illumination and emission color can be adjusted.SOLUTION: A light-emitting device includes a substrate, a plurality of light-emitting elements disposed on an upper surface of the substrate, a first wavelength conversion portion covering at least a portion of the light-emitting elements, a second wavelength conversion portion covering a portion of the first wavelength conversion portion, and a diffusion portion covering the first and second wavelength conversion portions. The light-emitting elements can be individually driven, and include, in a cross-sectional view, a first region in which the diffusion portion is disposed above the first wavelength conversion portion without the second wavelength conversion portion therebetween, and a second region in which the second wavelength conversion portion and the diffusion portion are sequentially disposed on the first wavelength conversion portion. A color temperature of light extracted from the second region is lower than a color temperature of light extracted from the first region.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a light emitting device. [Background technology]

[0002] A light emitting device is known that includes a substrate, a plurality of light emitting elements mounted on the substrate, a first wavelength conversion member that covers at least a portion of the top surface and at least a portion of the opposing side surfaces of at least two of the plurality of light emitting elements but does not cover at least a portion of the non-opposing side surfaces of the at least two light emitting elements, and a sealing material that seals the plurality of light emitting elements and the first wavelength conversion member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] WO2021 / 182413 issue Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure aims to provide a light-emitting device that is capable of adjusting light intensity and color. [Means for solving the problem]

[0005] A light-emitting device according to one embodiment of the present disclosure comprises a substrate, a plurality of light-emitting elements arranged on an upper surface of the substrate, a first wavelength conversion section covering at least a portion of the plurality of light-emitting elements, a second wavelength conversion section covering a portion of the first wavelength conversion section, and a diffusion section covering the first wavelength conversion section and the second wavelength conversion section, wherein the plurality of light-emitting elements can be driven individually, and in a cross-sectional view, the light-emitting device comprises a first region in which the diffusion section is arranged above the first wavelength conversion section without the second wavelength conversion section therebetween, and a second region in which the second wavelength conversion section and the diffusion section are arranged sequentially above the first wavelength conversion section, and the color temperature of the light extracted from the second region is lower than the color temperature of the light extracted from the first region. [Effects of the Invention]

[0006] According to an embodiment of the present disclosure, a light emitting device capable of adjusting light intensity and color can be provided. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a perspective view schematically showing a light emitting device according to a first embodiment. [Figure 2] 1 is a perspective view schematically illustrating a light emitting device according to a first embodiment, with part of the configuration thereof omitted. [Figure 3] FIG. 1 is a top view schematically showing a light emitting device according to a first embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 10 is a top view schematically showing a light emitting device according to a second embodiment. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] FIG. 10 is a cross-sectional view schematically showing a light emitting device according to a third embodiment. [Figure 8] FIG. 10 is a cross-sectional view schematically showing a light emitting device according to a fourth embodiment. [Figure 9] FIG. 10 is a cross-sectional view schematically showing a light emitting device according to a fifth embodiment. [Figure 10] FIG. 10 is a top view schematically showing a light emitting device according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] A light-emitting device according to the present disclosure (hereinafter, sometimes referred to as a "light-emitting device according to an embodiment") will be described below with reference to the drawings. In the following description, terms indicating specific directions or positions (e.g., "upper," "lower," and other terms including these terms) will be used as necessary. However, the use of these terms is intended to facilitate understanding of the invention with reference to the drawings, and the meaning of these terms does not limit the technical scope of the present disclosure. Furthermore, parts that appear with the same reference numerals in multiple drawings indicate the same or equivalent parts or components.

[0009] Furthermore, the embodiments shown below are intended to exemplify light-emitting devices and the like that embody the technical concepts of the present invention, and are not intended to limit the present invention thereto. Furthermore, unless otherwise specified, the dimensions, materials, shapes, relative arrangements, etc. of the components described below are intended for illustrative purposes only and are not intended to limit the scope of the present invention. Furthermore, the content described in one embodiment may also be applicable to other embodiments and modified examples. Furthermore, the size and positional relationships of components shown in the drawings may be exaggerated for clarity. Furthermore, to avoid overly complex drawings, schematic diagrams may be used in which some elements are omitted, or end views may be used as cross-sectional views that show only the cut surface.

[0010] First Embodiment The light emitting device according to the present disclosure comprises a substrate, a plurality of light emitting elements arranged on an upper surface of the substrate, a first wavelength conversion section covering at least a portion of the plurality of light emitting elements, a second wavelength conversion section covering a portion of the first wavelength conversion section, and a diffusion section covering the first wavelength conversion section and the second wavelength conversion section, wherein the plurality of light emitting elements can be driven individually, and in a cross-sectional view, the light emitting device comprises a first region in which the diffusion section is arranged above the first wavelength conversion section without the second wavelength conversion section therebetween, and a second region in which the second wavelength conversion section and the diffusion section are arranged sequentially above the first wavelength conversion section, and the color temperature of the light extracted from the second region is lower than the color temperature of the light extracted from the first region.

[0011] [Light-emitting device 1] As an example of a light emitting device according to the present disclosure, a light emitting device 1 will be described. FIG. 1 is a perspective view schematically showing the light emitting device according to the first embodiment. FIG. 2 is a perspective view schematically showing the light emitting device according to the first embodiment with part of the configuration omitted. FIG. 3 is a top view schematically showing the light emitting device according to the first embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3.

[0012] In each drawing, for reference, mutually orthogonal X-, Y-, and Z-axes are shown as necessary. The direction parallel to the X-axis is called the X-direction, the direction parallel to the Y-axis is called the Y-direction, and the direction parallel to the Z-axis is called the Z-direction. In the X-direction, the direction in which the arrow points is called the +X-direction, and the direction opposite the +X-direction is called the -X-direction. In the Y-direction, the direction in which the arrow points is called the +Y-direction, and the direction opposite the +Y-direction is called the -Y-direction. In the Z-direction, the direction in which the arrow points is called the +Z-direction, and the direction opposite the +Z-direction is called the -Z-direction. However, these do not limit the orientation of the light-emitting device when in use, and the orientation of the light-emitting device is arbitrary. Viewing an object from the +Z-direction toward the -Z-direction is called top view.

[0013] 1 to 4, the light emitting device 1 has a substrate 10 and a plurality of light emitting elements 30 arranged on an upper surface 10a of the substrate 10. The plurality of light emitting elements 30 can be driven individually. The light emitting device 1 also has a first wavelength conversion section 40 that covers at least a portion of the plurality of light emitting elements 30, a second wavelength conversion section 50 that covers a portion of the first wavelength conversion section 40, and a diffusion section 60 that covers the first wavelength conversion section 40 and the second wavelength conversion section 50. In the first embodiment, the first wavelength conversion section 40 covers all of the plurality of light emitting elements 30.

[0014] The light emitting device 1 may further include a package substrate 20, a wire 70, a covering member 80, and a reflective member 90. In the example of FIGS. 1 to 4, the substrate 10 is mounted on the upper surface 20a of the package substrate 20. A first terminal 11 is arranged on the upper surface 10a of the substrate 10, outside the area where the plurality of light emitting elements 30 are arranged. The package substrate 20 is larger than the substrate 10 in a top view. A second terminal 22 is arranged on the upper surface 20a of the package substrate 20, outside the area where the substrate 10 is mounted. The first terminal 11 of the substrate 10 is electrically connected to the second terminal 22 of the package substrate 20 by a wire 70. The first terminal 11, the second terminal 22, and the wire 70 are covered by a covering member 80 that is arranged on the outer periphery of the upper surface 10a of the substrate 10 and the outer periphery of the upper surface 20a of the package substrate 20. The reflective member 90 exposes the upper surfaces of the plurality of light emitting elements 30 and covers the side surfaces.

[0015] 2, for convenience of illustration, parts of the first wavelength-converting section 40, the second wavelength-converting section 50, the diffusion section 60, and the covering member 80 are omitted, and parts of the light-emitting element 30 and the wire 70 are visualized. Also, in FIG. 3, for convenience of illustration, the first region 101 is shown by a low-density dot pattern, and the second region 102 is shown by a high-density dot pattern.

[0016] In a cross-sectional view, the light emitting device 1 includes a first region 101 in which a diffusion section 60 is disposed above the first wavelength-converter 40 without a second wavelength-converter 50 therebetween, and a second region 102 in which the second wavelength-converter 50 and the diffusion section 60 are disposed in that order above the first wavelength-converter 40. The second wavelength-converter 50 can be disposed at any position on a part of the upper surface of the first wavelength-converter 40. The first region 101 and the second region 102 can be located inside the covering member 80 in a top view.

[0017] The first wavelength conversion section 40 converts incident light into light of a different wavelength and emits the converted light. The first wavelength conversion section 40 may output a portion of the incident light without converting it into light of a different wavelength, or may convert all of the incident light into light of a different wavelength and emit the converted light. The thickness of the first wavelength conversion section 40 may be, for example, approximately uniform. The second wavelength conversion section 50 converts incident light into light of a different wavelength and emits the converted light. The second wavelength conversion section 50 may output a portion of the incident light without converting it into light of a different wavelength, or may convert all of the incident light into light of a different wavelength and emit the converted light. The thickness of the second wavelength conversion section 50 may be, for example, approximately uniform. The diffusion section 60 diffuses the incident light and emits it. The diffusion section 60 does not perform wavelength conversion.

[0018] From the first region 101, light emitted from the light emitting element 30 and light emitted from the light emitting element 30 and wavelength-converted by the first wavelength conversion section can be extracted via the diffusion section 60. From the second region 102, light emitted from the light emitting element 30, light emitted from the light emitting element 30 and wavelength-converted by the first wavelength conversion section 40, light emitted from the light emitting element 30 and wavelength-converted by the second wavelength conversion section 50, and light emitted from the light emitting element 30 and wavelength-converted by the first wavelength conversion section 40 and the second wavelength conversion section 50 can be extracted via the diffusion section 60.

[0019] The peak emission wavelength of the light wavelength-converted by the first wavelength-converter 40 is shorter than the peak emission wavelength of the light wavelength-converted by the second wavelength-converter 50. As a result, the color temperature of the light extracted from the second region 102 is lower than the color temperature of the light extracted from the first region 101.

[0020] In the light emitting device 1, the plurality of light emitting elements 30 can be driven individually. Therefore, for example, by turning on some or all of the plurality of light emitting elements 30 located in the first region 101 and turning off all of the plurality of light emitting elements 30 located in the second region 102, it is possible to extract light only from the first region 101. Furthermore, by controlling the number of light emitting elements 30 that are to emit light among the plurality of light emitting elements 30 located in the first region 101, it is possible to perform dimming. Alternatively, by controlling the value of current flowing through each of the plurality of light emitting elements 30 located in the first region 101, it is possible to perform dimming.

[0021] Furthermore, by turning on some or all of the plurality of light-emitting elements 30 located in the second region 102 and turning off all of the plurality of light-emitting elements 30 located in the first region 101, it is possible to extract light only from the second region 102. Furthermore, by controlling the number of light-emitting elements 30 that are to emit light among the plurality of light-emitting elements 30 located in the second region 102, it is possible to adjust the light intensity. Alternatively, by controlling the value of the current flowing through each of the plurality of light-emitting elements 30 located in the second region 102, it is possible to adjust the light intensity.

[0022] Furthermore, by causing some or all of the plurality of light-emitting elements 30 located in the first region 101 and the second region 102 to emit light, it is possible to extract light from both the first region 101 and the second region 102. In this case, the light emitted from the light-emitting device 1 is a mixture of light from the first region 101 and light from the second region 102. In this case, light control is also possible by controlling the number of light-emitting elements 30 to emit light and the current value.

[0023] In this way, the light emitting device 1 enables dimming and color adjustment with a single light source by selecting the light emitting elements 30 to be turned on from among the plurality of light emitting elements 30. Furthermore, the light emitting device 1 has a diffusion section 60, which emits light in various directions. Therefore, when light is extracted from both the first region 101 and the second region 102, the light from each region is more likely to mix, improving color mixing properties.

[0024] Each component of the light emitting device 1 will be described below.

[0025] (Substrate 10) The substrate 10 includes a flat support member and wiring arranged on the upper surface of the support member. The substrate 10 has an element mounting region 10r on its upper surface 10a where a plurality of light-emitting elements 30 are mounted, and wiring is arranged in the element mounting region 10r. The substrate 10 has a plurality of first terminals 11 arranged on the upper surface 10a outside the element mounting region 10r, and the first terminals 11 are electrically connected to the wiring arranged in the element mounting region 10r.

[0026] In top view, the substrate 10 and the element mounting region 10r may be, for example, a rectangle having long and short sides. For example, a plurality of light-emitting elements 30 are mounted in a matrix in the element mounting region 10r. The light-emitting elements 30 are electrically connected to one of the first terminals 11. The light-emitting elements 30 may be connected in series or parallel to the first terminals 11 in groups of a predetermined number. For example, the element mounting region 10r may have a long side length of 8 mm or more and 18 mm or less, and a short side length of 2 mm or more and 6 mm or less.

[0027] Each of the first terminals 11 has, for example, a substantially circular, elliptical, or rectangular shape. The first terminals 11 are spaced apart from one another and arranged in a row along opposing long sides of the rectangular element mounting region 10r on the upper surface 10a of the substrate 10, sandwiching the element mounting region 10r. The interval between adjacent first terminals 11 may or may not be constant. The interval between adjacent first terminals 11 may be, for example, 20 μm or more and 100 μm or less. One end of a wire 70 is connected to the first terminal 11.

[0028] The substrate 10 is, for example, a semiconductor substrate such as silicon. On the upper surface 10a of the substrate 10, areas where no wiring is arranged are covered with, for example, an insulating film. Wiring may also be arranged inside or on the lower surface of the support member. For example, the substrate 10 can be an integrated circuit substrate on which circuits for individually driving and controlling the plurality of light-emitting elements 30 are integrated.

[0029] Examples of materials for the first terminal 11 and the wiring include metals such as Cu, Ag, Au, Al, Pt, Ti, W, Pd, Fe, and Ni, and / or alloys containing at least these metals.

[0030] (Package substrate 20) The package substrate 20 includes a flat substrate and wiring arranged at least on the upper surface side of the substrate. The package substrate 20 has a substrate mounting area 20r on its upper surface 20a for mounting the substrate 10, and further includes second terminals 22 on the upper surface 20a outside the substrate mounting area 20r. The substrate mounting area 20r is an area on which the substrate 10 is mounted. The substrate mounting area 20r is set as an area having approximately the same area as the shape of the substrate 10 when viewed from above. If the substrate 10 is rectangular when viewed from above, the substrate mounting area 20r can also be rectangular. Here, "approximately the same" is intended to include within an allowable range errors caused by material tolerances and mounting tolerances.

[0031] Each second terminal 22 has, for example, a substantially circular, elliptical, or rectangular shape. The second terminals 22 are spaced apart from one another on the upper surface 20a of the package substrate 20 and arranged in a row along opposing long sides of the rectangle, sandwiching the substrate mounting region 20r. The interval between adjacent second terminals 22 may or may not be constant. The interval between adjacent second terminals 22 may be, for example, 20 μm or more and 100 μm or less. The other end of the wire 70 is connected to the second terminal 22.

[0032] The base material constituting the package substrate 20 is preferably a material with high heat dissipation properties, and more preferably a material with high light-blocking properties and base material strength. Specific examples include metals such as Al and Cu; ceramics such as aluminum oxide, aluminum nitride, silicon nitride, and mullite; resins such as phenolic resin, epoxy resin, polyimide resin, BT resin (bismaleimide triazine resin), and polyphthalamide (PPA); and composite materials composed of resin and metal or ceramic (e.g., an inlay substrate in which a metal member is embedded in a resin). The base material may be flat, or may have a recess on its upper surface. In this case, the package substrate 20 has a recess whose bottom serves as a substrate mounting area 20r, and the substrate 10 can be mounted in the recess.

[0033] The package substrate 20 may include wiring for mounting the substrate 10 on the surface of the substrate mounting area 20r.

[0034] (light-emitting element) The light emitting element 30 has, for example, a substantially rectangular shape when viewed from above. For example, the light emitting element 30 can have a square shape with one side measuring 40 μm to 100 μm when viewed from above. The light emitting element 30 has positive and negative electrodes on the same side, and is flip-chip mounted on the substrate 10 with the side with the electrodes as the bottom surface. In this case, the top surface opposite the surface on which the electrodes are arranged is the main light extraction surface of the light emitting element 30.

[0035] In the light emitting device 1, the light emitting elements 30 are mounted on the substrate 10 in a row and column direction, aligned at predetermined intervals. The size and number of the light emitting elements 30 to be used can be selected appropriately depending on the type of light emitting device to be obtained. In particular, it is preferable to mount a larger number of smaller light emitting elements 30 at a higher density. This makes it possible to control the illumination range of the light emitted from the light emitting device 1 with a larger number of divisions. Such a light emitting device 1 can be used as a light source for a high-resolution lighting system. For example, the number of light emitting elements 30 provided in the light emitting device 1 can be between 1,000 and 100,000.

[0036] The light-emitting element 30 is, for example, a light-emitting diode. The light-emitting element 30 includes a semiconductor structure. The semiconductor structure includes an n-side semiconductor layer, a p-side semiconductor layer, and an active layer sandwiched between the n-side semiconductor layer and the p-side semiconductor layer. The active layer may have a single quantum well (SQW) structure or a multiple quantum well (MQW) structure including multiple well layers. The active layer is configured to be able to emit, for example, visible light or ultraviolet light.

[0037] The semiconductor structure may include multiple light-emitting sections, each including an n-side semiconductor layer, an active layer, and a p-side semiconductor layer. When the semiconductor structure includes multiple light-emitting sections, each light-emitting section may include well layers with different emission peak wavelengths or well layers with the same emission peak wavelength. The same emission peak wavelength also includes cases where the emission peak wavelengths vary by a few nanometers. The combination of emission peak wavelengths of the multiple light-emitting sections can be appropriately selected. For example, when the semiconductor structure includes two light-emitting sections, the combination of light emitted by each light-emitting section may be blue light with blue light, green light with green light, ultraviolet light with ultraviolet light, blue light with green light, blue light with ultraviolet light, or green light with ultraviolet light. For example, when the semiconductor structure includes three light-emitting sections, the combination of light emitted by each light-emitting section may be blue light, green light, and red light. Each light-emitting section may include one or more well layers with emission peak wavelengths different from those of the other well layers.

[0038] As the light emitting element 30, for example, a light emitting element capable of emitting blue light (light with a wavelength of 430 to 490 nm) can be used. However, the light emitting color of the light emitting element 30 can be selected from any wavelength depending on the application. For example, as a light emitting element for blue (light with a wavelength of 430 to 490 nm) or green (light with a wavelength of 495 to 565 nm), a nitride-based semiconductor (In x Al y Ga 1-x-y N (0≦x, 0≦y, x+y≦1), GaP, etc. can be used. As a red light emitting element (light with a wavelength of 610 to 700 nm), GaAlAs, AlInGaP, etc. can be used in addition to nitride-based semiconductor elements.

[0039] The light-emitting element 30 is bonded to wiring arranged in the element mounting region 10r of the substrate 10 by a conductive bonding member. When flip-chip mounting the light-emitting element 30 on the substrate 10, bumps made of a metal material such as Au, Ag, Cu, or Al can be used as the bonding member. Alternatively, solder such as an AuSn-based alloy or Sn-based lead-free solder can be used as the bonding member. Alternatively, a conductive adhesive made of resin containing conductive particles of metal or the like can be used as the bonding member. A plating method can be used to bond the light-emitting element 30 to the substrate 10. Examples of plating materials include Cu and Au. Alternatively, the electrodes of the light-emitting element 30 and the wiring of the substrate 10 can be directly connected to each other without a bonding member.

[0040] (First wavelength conversion unit) The first wavelength-converting portion 40 includes, for example, a resin and a phosphor. Examples of the resin include known translucent resins such as silicone resin and epoxy resin. Among them, silicone resin (specifically, translucent resins such as phenyl silicone resin and dimethyl silicone resin) is preferably used because of its excellent reliability.

[0041] The phosphor is an yttrium-aluminum-garnet phosphor (e.g., (Y,Gd)3(Al,Ga)5O 12:(Ce), lutetium-aluminum-garnet-based phosphor (e.g., Lu3(Al,Ga)5O 12 :(Ce), terbium-aluminum-garnet-based phosphor (e.g., Tb3(Al,Ga)5O 12 :(Ce), CCA-based phosphor (e.g., Ca 10 (PO4)6Cl2:Eu), SAE-based phosphor (e.g., Sr4Al 14 O 25 :Eu), chlorosilicate-based phosphor (e.g., Ca8MgSi4O 16 Cl2:Eu), silicate-based phosphor (e.g., (Ba,Sr,Ca,Mg)2SiO4:Eu), β-sialon-based phosphor (e.g., (Si,Al)3(O,N)4:Eu) or α-sialon-based phosphor (e.g., Ca(Si,Al) 12 (O,N) 16 :Eu) and other oxynitride-based phosphors, LSN-based phosphors (e.g., (La,Y)3Si6N 11 :Ce), BSESN-based phosphors (e.g., (Ba,Sr)2Si5N8:Eu), SLA-based phosphors (e.g., SrLiAl3N4:Eu), CASN-based phosphors (e.g., CaAlSiN3:Eu) or SCASN-based phosphors (e.g., (Sr,Ca)AlSiN3:Eu) and other nitride-based phosphors, KSF-based phosphors (e.g., K2SiF6:Mn), KSAF-based phosphors (e.g., K2(Si 1-x Al x )F 6-x :Mn where x satisfies 0 < x < 1.), or fluoride-based phosphors such as MGF-based phosphors (e.g., 3.5MgO·0.5MgF2·GeO2:Mn), 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.

[0042] When the light-emitting element 30 can emit blue light, the first wavelength-converting section 40 can be excited by blue light to emit yellow light. In this case, the phosphor contained in the first wavelength-converting section 40 can be an yttrium-aluminum-garnet phosphor (e.g., (Y,Gd)3(Al,Ga)5O 12 :Ce). With this configuration, white light is obtained from the first region 101 by mixing the blue light that has passed through the first wavelength-converter 40 and the yellow light that is emitted by the first wavelength-converter 40.

[0043] (Second wavelength conversion unit) The second wavelength-converter 50 includes, for example, a resin and a phosphor. The resin and phosphor exemplified for the first wavelength-converter 40 may be used as the resin and phosphor.

[0044] When the light-emitting element 30 is capable of emitting blue light, the second wavelength converter 50 can be excited by the blue light to emit amber light, for example. In this case, examples of the phosphor contained in the second wavelength converter 50 include nitride phosphors such as CASN phosphors (e.g., CaAlSiN3:Eu) and SCASN phosphors (e.g., (Sr,Ca)AlSiN3:Eu), and KSF phosphors (e.g., K2SiF6:Mn).

[0045] When the light-emitting element 30 is capable of emitting blue light, the first wavelength conversion section 40 is capable of emitting yellow light, and the second wavelength conversion section 50 is capable of emitting amber light, white light having a lower color temperature than the white light obtained from the first region 101 is obtained from the second region 102 by mixing the blue light that has passed through the first wavelength conversion section 40 and the second wavelength conversion section 50, the yellow light that is emitted by the first wavelength conversion section 40 and passes through the second wavelength conversion section 50, and the amber light that is emitted by the second wavelength conversion section 50.

[0046] (Diffusion section) The diffusion section 60 includes, for example, a resin and a light diffusion material. The resin may be any of the resins exemplified for the first wavelength conversion section 40. The light diffusion material may be titanium oxide, zinc oxide, silicon oxide, zirconium oxide, aluminum oxide, aluminum nitride, or the like.

[0047] (wire) The wires 70 can be made of metals such as Au, Ag, Cu, Pt, and Al and / or alloys containing at least these metals. Au, which has excellent thermal resistance, is particularly preferred. The diameter of the wires 70 can be, for example, 15 μm to 50 μm. The wires 70 can be arranged across the long sides of the substantially rectangular substrate 10 in a top view, for example, so as to be substantially perpendicular to the long sides. Furthermore, among the multiple wires 70 arranged in a row along the long sides of the substrate 10, the wires 70 located in the center of the row can be arranged so as to be substantially perpendicular to the long sides of the substrate 10 in a top view, as described above, while the wires 70 located at the ends of the row can be arranged diagonally relative to the long sides of the substrate 10 in a top view. The interval at which the wires 70 are aligned can be 20 μm to 100 μm.

[0048] (Covering material) The covering member 80 is a light-shielding member that covers the wires 70 outside the element mounting region 10r. Note that, as an example, the covering member 80 is arranged in a frame shape in a top view so as to cover the wires 70 and surround the element mounting region 10r.

[0049] The covering member 80 is disposed at a distance from the light emitting element 30 in a top view. The covering member 80 is preferably disposed so that its height (i.e., the distance from the upper surface 20a of the package substrate 20 to the upper surface of the covering member 80) is greatest directly above the top of the wire 70. In other words, the covering member 80 is preferably disposed so that its top overlaps the top of the wire 70.

[0050] Examples of the covering member 80 include resins containing a light-blocking filler. Examples of the base resin include silicone resin, modified silicone resin, epoxy resin, modified epoxy resin, and acrylic resin. Examples of the light-blocking filler include light-absorbing materials such as pigments, carbon black, titanium black, and graphite, and light-reflecting materials such as titanium oxide, aluminum oxide, zinc oxide, barium carbonate, barium sulfate, boron nitride, aluminum nitride, and glass fillers. Specifically, the exterior color of the covering member 80 may be white, which has excellent light reflectivity, black, which has excellent light absorption, or gray, which has both light reflectivity and light absorption properties. The covering member 80 may also be formed by stacking multiple resin layers. In particular, considering the deterioration of the resin due to light absorption, it is preferable that the covering member 80 use a light-reflective white resin on at least the outermost surface.

[0051] (reflective material) The reflective member 90 is a member that covers the upper surface 10a of the substrate 10 and the side surfaces of the light-emitting elements 30. The upper surface of the light-emitting elements 30 is exposed from the reflective member 90. The reflective member 90 may cover the area between the lower surface of the light-emitting elements 30 and the substrate 10. The reflective member 90 can reflect light emitted from the side surfaces of the light-emitting elements 30 upward. This can improve the light extraction efficiency of the light-emitting device 1. In addition, when the light-emitting elements 30 are individually lit, the boundary between the light-emitting area and the non-light-emitting area can be made clear. This improves the contrast ratio between the light-emitting area and the non-light-emitting area.

[0052] The reflective member 90 is preferably made of a soft resin with relatively low elasticity and excellent shape conformability. The reflective member 90 can be made of a resin material with good transparency and insulating properties, such as a thermosetting resin such as an epoxy resin or a silicone resin. The reflective member 90 is preferably made of a white resin containing particles of a light-reflecting material in a base resin. Examples of the light-reflecting material include light-reflecting materials similar to the light-reflecting materials contained in the covering member described above. The reflective member 90 may also contain a light-absorbing material such as carbon black, titanium black, or graphite.

[0053] The light emitting device 1 having the above configuration can be used, for example, as a light source for a vehicle headlight. In this case, for example, a configuration is adopted in which light is emitted from the light source to the outside through a lens. Since the light emitting device 1 can adjust the brightness and color with a single light source, it is possible to reduce the size of the vehicle headlight.

[0054] The visibility of vehicle headlight light varies depending on factors such as weather. To improve the visibility of vehicle headlight light, it is preferable to use light with a high color temperature on sunny days and light with a low color temperature or light with both high and low color temperatures on rainy or foggy days. Using the light-emitting device 1 as the light source for vehicle headlights makes such control possible.

[0055] When the light emitting device 1 is used as a light source for a vehicle headlight, the area of the first region 101 is preferably larger than the area of the second region 102 when viewed from above. It is more preferable that the area of the first region 101 is 105% to 130% of the area of the second region 102 when viewed from above. In rain or fog, light with a higher color temperature is scattered more, resulting in a lower transmittance. By setting the relationship between the areas of the first region 101 and the second region 102 as described above, light with a higher color temperature can be transmitted farther even in rain or fog. As a result, when light is extracted from the first region 101 and the second region 102 in rain or fog, the brightness of each region can be made uniform.

[0056] [Method of manufacturing the light emitting device 1] (Step of mounting the light emitting element 30 on the substrate 10) First, a substrate 10 is prepared, which has an element mounting region 10r and first terminals 11 disposed outside the element mounting region 10r on its upper surface 10a. The substrate 10 can be prepared, for example, by preparing a flat support member made of silicon or the like, and forming wiring and the first terminals 11 by plating, sputtering, vapor deposition, or the like. In the description of the manufacturing method, "preparing" a component does not necessarily mean manufacturing the component, but also includes acquiring the component, such as purchasing or receiving the component.

[0057] Next, the light emitting element 30 is mounted on the element mounting region 10r of the substrate 10. The light emitting element 30 can be mounted by flip-chip mounting on the element mounting region 10r on the upper surface 10a of the substrate 10. The light emitting element 30 can be prepared through some or all of multiple steps, such as a step of forming a semiconductor laminate and a step of forming element electrodes.

[0058] If necessary, the method may include a step of covering the side surfaces of the light-emitting elements 30 with a reflective member 90 after mounting the light-emitting elements 30 on the element mounting region 10r of the substrate 10. For example, after mounting the light-emitting elements 30 on the substrate 10, a mask is placed that covers the first terminals 11 and exposes the element mounting region 10r. Then, a reflective member 90 such as an uncured white resin is placed in an area separated from the light-emitting elements 30, and the white resin is allowed to flow and be positioned between the opposing side surfaces of adjacent light-emitting elements 30 and cured. After the reflective member 90 is placed, the mask is removed, exposing the first terminals 11 from the reflective member 90. The reflective member 90 may also be placed between the lower surface of the light-emitting elements 30 and the substrate 10.

[0059] (Step of placing the substrate 10 on the package substrate 20) Next, a package substrate 20 is prepared, which has a substrate mounting area 20r on which the substrate 10 is mounted, and second terminals 22 located outside the substrate mounting area 20r, on its upper surface 20a. The package substrate 20 can be prepared, for example, by forming wiring such as Cu and the second terminals 22 on a flat support member made of metal, ceramic, or the like by plating, sputtering, vapor deposition, or the like. Next, the substrate 10 on which the light-emitting element 30 is mounted is placed on the substrate mounting area 20r of the package substrate 20. The substrate 10 and the package substrate 20 can be bonded together via a bonding member such as a sintered body containing Ag.

[0060] (Process of connecting with wire 70) Next, the first terminal 11 of the substrate 10 and the second terminal 22 of the package substrate 20 are connected by the wire 70. For example, the wire 70 is first connected to the first terminal 11 of the substrate 10, and then connected to the second terminal 22 of the package substrate 20. By connecting the wire 70 in this order, the top of the wire 70 can be positioned closer to the first terminal 11. This allows the wire 70 to be positioned along the step between the substrate 10 and the package substrate 20. Therefore, in the step of arranging the covering member 80 described below, the amount of resin positioned below the wire 70 is reduced, and the risk of the wire 70 being broken due to thermal expansion of the covering member 80 can be reduced.

[0061] (Step of arranging the first wavelength-converting section 40, the second wavelength-converting section 50, and the diffusion section 60) Next, a first wavelength conversion section 40 is disposed on the upper surface 10a of the substrate 10. The first wavelength conversion section 40 covers the upper surface of the light emitting element 30 and exposes the first terminal 11. For example, a sheet-shaped member having a predetermined size is prepared in advance as the first wavelength conversion section 40 and disposed on the light emitting element 30. The first wavelength conversion section 40 may be fixed to the light emitting element 30 via a translucent bonding member such as resin, or may be fixed without a bonding member by utilizing the tackiness of the first wavelength conversion section 40. Instead of disposing a sheet-shaped member on the light emitting element 30, the first wavelength conversion section 40 may be applied to the light emitting element 30 by spraying or the like. Alternatively, the first wavelength conversion section 40 may be formed by injection molding using a mold or the like, transfer molding, compression molding, or the like.

[0062] Next, a second wavelength-converting section 50 is arranged to cover a part of the first wavelength-converting section 40. The second wavelength-converting section 50 can be arranged, for example, by the same method as for the first wavelength-converting section 40. Next, a diffusing section 60 is arranged to cover the first wavelength-converting section 40 and the second wavelength-converting section 50. The diffusing section 60 can be arranged, for example, by the same method as for the first wavelength-converting section 40.

[0063] (Step of placing the covering member 80) Next, a covering member 80 that covers the first terminals 11, the second terminals 22, and the wires 70 is placed on the outer periphery of the upper surface 10a of the substrate 10 and on the outer periphery of the upper surface 20a of the package substrate 20. The covering member 80 can be placed, for example, by supplying uncured resin to a predetermined position using a dispenser or the like and then curing it. Note that the covering member 80 may be placed after the first wavelength-converting section 40 and the second wavelength-converting section 50 are placed, and then the diffusion section 60 may be placed. Through the above steps, the light-emitting device 1 is completed.

[0064] Second Embodiment FIG. 5 is a top view schematically showing a light emitting device according to a second embodiment. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. As shown in FIGS. 5 and 6, the light emitting device 1A according to the second embodiment differs from the light emitting device 1 according to the first embodiment in that it further includes a third region 103 in addition to the first region 101 and the second region 102. The first region 101, the second region 102, and the third region 103 may be located inside the covering member 80 in a top view. However, the positional relationship between the first region 101, the second region 102, and the third region 103 is not limited to the arrangement shown in FIG. 5.

[0065] The third region 103 is a region where the diffusion section 60 covers the light emitting element 30 without the first wavelength conversion section 40 or the second wavelength conversion section 50. Light emitted from the light emitting element 30 can be extracted from the third region 103 only via the diffusion section 60. For example, if the light emitting element 30 can emit blue light, the blue light can be extracted from the third region 103. Blue light has high energy and can therefore be irradiated over a longer distance.

[0066] In the light emitting device 1A, the plurality of light emitting elements 30 can be driven individually. Therefore, for example, by turning on some or all of the plurality of light emitting elements 30 located in the third region 103 and turning off all of the plurality of light emitting elements 30 located in the first region 101 and the second region 102, it is possible to extract light only from the third region 103. Furthermore, by controlling the number of light emitting elements 30 that are to be turned on among the plurality of light emitting elements 30 located in the third region 103, it is possible to perform dimming. Alternatively, by controlling the value of the current flowing through each of the plurality of light emitting elements 30 located in the third region 103, it is possible to perform dimming. Similar to the light emitting device 1, dimming and color adjustment are possible in the first region 101 and the second region 102.

[0067] When the light emitting device 1A is used as a light source for a vehicle headlight, the area of the first region 101 is preferably larger than the area of the second region 102 and smaller than the area of the third region 103 in a top view. More preferably, the area of the first region 101 is 105% to 130% of the area of the second region 102 and 35% to 65% of the area of the third region 103 in a top view. In rain or fog, light with a higher color temperature is scattered more, resulting in a lower transmittance. By setting the area relationship among the first region 101, the second region 102, and the third region 103 as described above, light with a higher color temperature can be transmitted farther even in rain or fog. As a result, when light is extracted from the first region 101, the second region 102, and the third region 103 in rain or fog, the brightness of each region can be made uniform.

[0068] Third Embodiment FIG. 7 is a cross-sectional view schematically illustrating a light-emitting device according to a third embodiment. As shown in FIG. 7, the light-emitting device 1B according to the third embodiment differs from the light-emitting device 1 according to the first embodiment in that, in a cross-sectional view, it has a region 50R at the end of the second wavelength-converter 50 where the thickness of the second wavelength-converter 50 gradually decreases. In a cross-sectional view, the inclined surface of the region 50R may be linear or curved. As long as the thickness of the second wavelength-converter 50 gradually decreases, the shape does not have to be linear or curved. In the second wavelength-converter 50, the thickness of the region other than the region 50R is approximately constant.

[0069] In this way, the light emitting device 1B includes the region 50R where the thickness of the second wavelength-converter 50 gradually decreases, and therefore the color tone changes stepwise in the region 50R, thereby improving color mixing properties.

[0070] <Fourth embodiment> FIG. 8 is a cross-sectional view schematically illustrating a light-emitting device according to the fourth embodiment. As shown in FIG. 8, the light-emitting device 1C according to the fourth embodiment differs from the light-emitting device 1 according to the first embodiment in that, in a cross-sectional view, it includes a region 60R at the end of the diffusion section 60 where the thickness of the diffusion section 60 gradually decreases. The region 60R is disposed so as to include the boundary between the first region 101 and the second region 102. In a cross-sectional view, the inclined surface of the region 60R may be linear or curved. As long as the thickness of the diffusion section 60 gradually decreases, it does not have to be linear or curved. In the diffusion section 60, the thickness of the regions other than the region 60R is approximately constant.

[0071] In this way, the light emitting device 1C includes the region 60R where the thickness of the diffusion portion 60 gradually decreases, and therefore the color tone changes stepwise in the region 60R, thereby improving color mixing properties.

[0072] The light emitting device 1C may further include a region 50R in which the thickness of the second wavelength-converter 50 gradually decreases. By providing both the region 50R and the region 60R, the color mixing performance can be further improved.

[0073] Fifth Embodiment FIG. 9 is a cross-sectional view schematically illustrating a light-emitting device according to a fifth embodiment. As shown in FIG. 9, in a light-emitting device 1D according to the fifth embodiment, the boundary between the first wavelength-converter 40 and the second wavelength-converter 50 is located directly above one or more of the light-emitting elements 30 in a top view. That is, the boundary between the first region 101 and the second region 102 (two boundaries in the example of FIG. 9) is located directly above one or more of the light-emitting elements 30. This can further improve color mixing. Furthermore, it is preferable that the boundary 50S between the region 50R with a constant thickness of the second wavelength-converter 50 is located directly above one or more of the light-emitting elements 30. This can further improve color mixing.

[0074] Sixth Embodiment Fig. 10 is a top view schematically showing a light emitting device according to the sixth embodiment. For convenience, in Fig. 10, the first region 101 is shown by a low-density dot pattern, and the second region 102 is shown by a high-density dot pattern. As shown in Fig. 10, in the light emitting device 1E according to the sixth embodiment, the second region 102 is disposed around the first region 101 in a top view.

[0075] 10, the upper surface 20a of the package substrate 20 is rectangular, with its long sides parallel to the X direction and its short sides parallel to the Y direction. The thickness direction of the light emitting device 1E is the Z direction. In this case, the cross section of the light emitting device 1E taken along a plane passing through the first region 101 and the second region 102 and parallel to the YZ plane will be the same as that shown in FIG.

[0076] The color temperature of the light extracted from the first region 101 is higher than the color temperature of the light extracted from the second region 102. Therefore, the first region 101 is an area that can extract light with higher output than the second region 102, and the first region 101 can irradiate light farther than the second region 102. However, since light with a high color temperature is easily scattered by fog, etc., the second region 102, which has a lower color temperature and is arranged around the first region 101, irradiates the vicinity. This allows for optimal illumination of the vicinity and illumination of the distant area. When the light emitting device 1E is used as a light source for a vehicle headlight, the first region 101 can be used as a high beam area.

[0077] Although the preferred embodiments have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the claims.

[0078] In addition to the above-described embodiments, the following supplementary notes are also disclosed. [Appendix 1] A substrate; a plurality of light-emitting elements disposed on an upper surface of the substrate; a first wavelength converting portion that covers at least a portion of the plurality of light emitting elements; a second wavelength-converting portion covering a portion of the first wavelength-converting portion; a diffusion portion that covers the first wavelength-converting portion and the second wavelength-converting portion, The plurality of light-emitting elements can be driven individually, a first region in which, in a cross-sectional view, the diffusion section is disposed above the first wavelength-converting section without the second wavelength-converting section therebetween, and a second region in which the second wavelength-converting section and the diffusion section are disposed in this order above the first wavelength-converting section; A light emitting device, wherein the color temperature of the light extracted from the second region is lower than the color temperature of the light extracted from the first region. [Appendix 2] 2. The light emitting device according to claim 1, further comprising a region where the thickness of the second wavelength-converter gradually decreases at an end of the second wavelength-converter in a cross-sectional view. [Appendix 3] 3. The light emitting device according to claim 1, wherein the diffusion portion has a region where the thickness of the diffusion portion gradually decreases at an end of the diffusion portion in a cross-sectional view. [Appendix 4] 4. The light-emitting device according to claim 1, wherein, in a top view, the boundary between the first wavelength conversion section and the second wavelength conversion section is located directly above one or more of the plurality of light-emitting elements. [Appendix 5] 5. The light emitting device according to any one of claims 1 to 4, wherein the first region is a region capable of extracting light with a higher output than the second region, and the second region is arranged around the first region when viewed from above. [Appendix 6] 6. The light emitting device according to claim 1, wherein the area of the first region is larger than the area of the second region when viewed from above. [Appendix 7] 7. The light emitting device according to claim 6, wherein the area of the first region is 105% to 130% of the area of the second region when viewed from above. [Appendix 8] 8. The light emitting device according to claim 1, wherein the diffusion section further comprises a third region that covers the light emitting element without the first wavelength conversion section and the second wavelength conversion section intervening therebetween. [Appendix 9] 9. The light emitting device according to claim 8, wherein, in a top view, an area of the first region is larger than an area of the second region and smaller than an area of the third region. [Appendix 10] 10. The light emitting device according to claim 9, wherein, in a top view, the area of the first region is 105% to 130% of the area of the second region, and 35% to 65% of the area of the third region. [Appendix 11] the light-emitting element is capable of emitting blue light, the first wavelength-converting unit is excited by blue light to emit yellow light, 11. The light emitting device according to claim 1, wherein the second wavelength converting portion is excited by blue light and is capable of emitting amber light. [Explanation of symbols]

[0079] 1, 1A, 1B, 1C, 1D, 1E Light-emitting device 10 Substrate 10a top surface 10r Element mounting area 11 1st terminal 20 Package substrate 20a top surface 20r Substrate placement area 22 2nd terminal 30 Light-emitting element 40 First wavelength conversion unit 50 Second wavelength conversion unit 50R area 50S boundary 60 Diffusion section 60R area 70 wire 80 Covering material 90 Reflective material 101 First area 102 Second area 103 Third area

Claims

1. A substrate; a plurality of light-emitting elements disposed on an upper surface of the substrate; a first wavelength conversion unit that covers at least a portion of the plurality of light-emitting elements; a second wavelength-converting portion covering a portion of the first wavelength-converting portion; a diffusion portion that covers the first wavelength-converting portion and the second wavelength-converting portion, The plurality of light-emitting elements can be driven individually, a first region in which, in a cross-sectional view, the diffusion section is disposed above the first wavelength-converting section without the second wavelength-converting section therebetween, and a second region in which the second wavelength-converting section and the diffusion section are disposed in this order above the first wavelength-converting section, A light emitting device, wherein the color temperature of the light extracted from the second region is lower than the color temperature of the light extracted from the first region.

2. The light emitting device according to claim 1 , further comprising a region where the thickness of the second wavelength-converting portion gradually decreases at an end of the second wavelength-converting portion in a cross-sectional view.

3. The light emitting device according to claim 1 , wherein the diffusion portion has a region where the thickness gradually decreases at an end of the diffusion portion in a cross-sectional view.

4. The light emitting device according to claim 1 , wherein, in a top view, a boundary between the first wavelength conversion portion and the second wavelength conversion portion is located directly above one or more of the plurality of light emitting elements.

5. The light emitting device according to claim 1 , wherein the first region is a region capable of extracting light with a higher output than the second region, and the second region is disposed around the first region in a top view.

6. The light emitting device according to claim 1 , wherein an area of the first region is larger than an area of the second region when viewed from above.

7. The light emitting device according to claim 6 , wherein the area of the first region is 105% to 130% of the area of the second region when viewed from above.

8. The light emitting device according to claim 1 , further comprising a third region in which the diffusion portion covers the light emitting element without the first wavelength converting portion and the second wavelength converting portion intervening therebetween.

9. The light emitting device according to claim 8 , wherein an area of the first region is larger than an area of the second region and smaller than an area of the third region in a top view.

10. The light emitting device according to claim 9 , wherein, in a top view, the area of the first region is 105% to 130% of the area of the second region, and 35% to 65% of the area of the third region.

11. the light-emitting element is capable of emitting blue light, the first wavelength-converting unit is excited by blue light to emit yellow light, The light emitting device according to claim 1 , wherein the second wavelength-converting portion is excited by blue light and is capable of emitting amber light.

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