JP7348478B2 - Light emitting device and its manufacturing method - Google Patents

Description

The present invention relates to a light emitting device and a method for manufacturing the same.

In recent years, light-emitting devices including light-emitting elements such as light-emitting diodes have been used for various purposes, and there is a demand for light-emitting devices with higher light extraction efficiency. For example, Patent Document 1 describes a light-emitting device that improves light extraction efficiency by including a filler-containing resin that covers the side surface of a silicon substrate of a semiconductor light-emitting element and exposes the top surface of the semiconductor light-emitting element. ing.

JP2014-241341A

An object of the present invention is to provide a light-emitting device and a method for manufacturing a light-emitting device that can further improve light extraction efficiency in a light-emitting device equipped with a filler-containing resin (reflective particle-containing member).

A light emitting device according to one aspect of the present invention includes a substrate having a base material having an upper surface, a first wiring arranged on the upper surface, a first light extraction surface, and an opposite side of the first light extraction surface. a first electrode forming surface located on the surface, a first side surface located between the first light extraction surface and the first electrode forming surface, and a pair of first electrodes on the first electrode forming surface; a first light emitting element placed on the first wiring such that the first electrode forming surface and the first wiring face each other, and the first light extraction surface is exposed and the upper surface of the base material is covered; , a first reflective member containing reflective particles; the first light extraction surface is exposed, and at least a portion of the first reflective member and the first side surface are covered; a first covering member having a low concentration of the second covering member, a second covering member covering at least a portion of the first side surface, and a second covering member surrounding the second covering member in a top view, the second covering member and the first reflecting member; a second reflective member in contact with the first reflective member, the second reflective member having a narrow portion in contact with the first reflective member and a wide portion disposed above the narrow width portion in cross-sectional view. .

Further, a method for manufacturing a light emitting device according to one aspect of the present invention includes the steps of preparing a substrate including a base material having an upper surface and a first wiring disposed on the upper surface; , a first electrode forming surface on the opposite side of the first light extraction surface, a first side surface between the first light extraction surface and the first electrode forming surface, and a pair on the first electrode forming surface. a step of preparing a first light emitting element having a first electrode; and a step of placing the first light emitting element on the first wiring with the first electrode forming surface and the first wiring facing each other. and arranging the reflective particle-containing member on the upper surface of the base material so that at least a part of the upper surface of the base material that overlaps with the first light emitting element is exposed when viewed from above; The method includes the step of spreading the reflective particle-containing member on the overlapping upper surface of the base material by centrifugal force.

According to the light emitting device of the embodiment of the present invention, it is possible to provide a light emitting device with improved light extraction efficiency.

FIG. 1A is a schematic perspective view of a light emitting device according to Embodiment 1. FIG. 1B is a schematic perspective view of a light emitting device according to Embodiment 1. FIG. 2A is a schematic top view of the light emitting device according to Embodiment 1. FIG. 2B is a schematic cross-sectional view taken along line IIB-IIB in FIG. 2A. FIG. 2C is a schematic end view taken along line IIC-IIC in FIG. 2A. FIG. 3 is a schematic cross-sectional view of a modification of the light emitting device according to the first embodiment. FIG. 4 is a schematic cross-sectional view of a modification of the light emitting device according to the first embodiment. FIG. 5 is a schematic cross-sectional view of a modification of the light emitting device according to the first embodiment. FIG. 6 is a schematic top view of the substrate according to the first embodiment. FIG. 7 is a schematic rear view of the light emitting device according to the first embodiment. FIG. 8 is a schematic front view of the light emitting device according to the first embodiment. FIG. 9 is a schematic side view of the light emitting device according to the first embodiment. FIG. 10 is a schematic cross-sectional view of a light emitting device according to Embodiment 2. FIG. 11 is a schematic cross-sectional view for explaining the method for manufacturing the light emitting device according to the first embodiment. FIG. 12 is a schematic cross-sectional view for explaining the method for manufacturing the light emitting device according to the first embodiment. FIG. 13 is a schematic diagram for explaining the method for manufacturing the light emitting device according to the first embodiment. FIG. 14 is a schematic cross-sectional view for explaining the method for manufacturing the light emitting device according to the first embodiment. FIG. 15 is a schematic cross-sectional view for explaining the method for manufacturing the light emitting device according to the first embodiment. FIG. 16 is a schematic cross-sectional view for explaining the method for manufacturing the light emitting device according to the first embodiment. FIG. 17 is a schematic cross-sectional view for explaining the method for manufacturing the light emitting device according to the first embodiment. FIG. 18 is a schematic cross-sectional view for explaining the method for manufacturing the light emitting device according to the first embodiment.

Embodiments of the invention will be described below with reference to the drawings as appropriate. However, the light emitting device described below is for embodying the technical idea of the present invention, and the present invention is not limited to the following unless there is a specific description. What is described in one embodiment is applicable to other embodiments and modifications. Furthermore, the sizes, positional relationships, etc. of members shown in the drawings may be exaggerated for clarity of explanation. Furthermore, the same names and symbols indicate the same or homogeneous members, and detailed explanations will be omitted as appropriate.

<Embodiment 1>
A light emitting device 1000 according to an embodiment of the present invention will be described based on FIGS. 1A to 9. The light emitting device 1000 includes a substrate 10, at least one first light emitting element 20A, a first reflecting member 31, a first covering member 32, a second covering member 33, and a second reflecting member 40. The substrate 10 includes a base material 11 having an upper surface 111 and a first wiring 12 arranged on the upper surface 111 of the base material 11. The first light emitting element 20A includes a first light extraction surface 201A, a first electrode formation surface 203A opposite to the first light extraction surface, and a first light extraction surface 203A located between the first light extraction surface and the first electrode formation surface. It has one side surface 202A and a pair of first electrodes 21A and 22A on a first electrode forming surface 203A. The first light emitting element 20A is placed on the first wiring 12 with the first electrode forming surface 203A and the first wiring 12 facing each other. The first light emitting element 20A is electrically connected to the first wiring 12. The first reflective member 31 exposes the first light extraction surface 201A and covers the upper surface 111 of the base material 11. Moreover, the first reflective member 31 contains reflective particles. The first covering member 32 exposes the first light extraction surface 201A and covers at least a portion of the first reflecting member 31 and the first side surface 202A. Further, the first coating member 32 has a lower concentration of reflective particles than the first reflective member 31. The second covering member 33 covers at least a portion of the first side surface 202A. The second reflective member 40 surrounds the second covering member 33 when viewed from above. Further, the second reflecting member 40 is in contact with the second covering member 33 and the first reflecting member 31. The second reflecting member 40 has a narrow portion 42 in contact with the first reflecting portion 31 and a wide portion 41 disposed above the narrow portion 42 in a cross-sectional view. Note that a second light emitting element 20B, a third light emitting element 20C, and a first light emitting element 20A, which will be described later, may be referred to as light emitting elements.

The first covering member 32 has a lower concentration of reflective particles than the first reflecting member 31, and thus has a higher light transmittance than the first reflecting member 31. Therefore, by providing the first covering member 32 that covers the first side surface 202A, the light from the first light emitting element 20A can be extracted from the first covering member 32 having a high light transmittance. Thereby, the light extraction efficiency of the light emitting device can be improved.

By covering the upper surface of the base material 11 with the first reflective member 31 containing reflective particles and having a high reflectance, absorption of light from the first light emitting element 20A by the substrate 10 can be suppressed. Thereby, the light extraction efficiency of the light emitting device can be improved.

As a procedure for forming the first reflective member 31 and the first covering member 32, the first covering member that covers the first reflective member may be formed after forming the first reflective member, and the first reflective member and the first covering member 32 may be formed. One covering member may be formed in the same process. For example, after forming the first reflective member, the uncured first coating member is placed on the upper surface of the base material by potting or the like, and the first coating member is cured. This may form a first covering member that covers the first reflective member. When forming the first reflective member and the first coating member in the same process, for example, the reflective particle-containing member containing reflective particles before being cured is placed on the substrate, and the reflective particles of the reflective particle-containing member are moved by centrifugal force. Sediment with etc. When the reflective particles of the reflective particle-containing member are allowed to settle, the reflective particle-containing member has a reflective part in which the reflective particles are unevenly distributed, and a transparent part located above the reflective part and in which the reflective particles are not unevenly distributed. It is formed. In addition, in the reflective particle-containing member, the reflective part where reflective particles are unevenly distributed is called a first reflective member 31, and the transparent part located above the reflective part and where reflective particles are not unevenly distributed is called a first covering member 32. Sometimes. When forming the first covering member by settling the reflective particles of the reflective particle-containing member, the first covering member 32 may contain reflective particles that do not settle depending on the particle size or the like. By settling the reflective particles of the reflective particle-containing member, the thickness of the first reflective member 31 can be easily reduced. This makes it easier to take out the light from the first covering member 32 from the first light emitting element 20A, thereby improving the light extraction efficiency of the light emitting device. When the reflective particles of the reflective particle-containing member are precipitated, the first reflective member 31 is a portion of the reflective particle-containing member in which the content of reflective particles is 10 wt% or more, and the first coating member 32 is This is a portion in the reflective particle-containing member where the reflective particle content is lower than 10 wt%. Note that "wt%" is weight percent, and represents the ratio of the weight of the reflective particles to the total weight of the reflective particle-containing member.

The base material of the first covering member 32 only needs to have translucency, and for example, a known material such as silicone resin can be used. Note that "light transmittance" means that the light transmittance of the first light emitting element at the emission peak wavelength is preferably 60% or more, more preferably 70% or more, and preferably 80% or more. Even more preferable. When forming the first reflective member 31 and the first covering member 32 in the same process, a member containing reflective particles in a known translucent base material can be used as the reflective particle-containing member. For the first reflective member 31, a member containing reflective particles in a base material can be used. As the reflective particles, known materials such as titanium oxide can be used. The first reflective member 31 only needs to have a reflective property to reflect light from the first light emitting element, and for example, a member containing reflective particles in a base material can be used. The reflectance of the first reflective member at the emission peak wavelength of the first light emitting element is preferably 60% or more, more preferably 70% or more, and even more preferably 80% or more.

The first covering member 32 may be in contact with the second reflecting member 40, and the first covering member 32 may not be in contact with the second reflecting member 40. When the first covering member 32 is in contact with the second reflecting member 40, the area of the first covering member 32 having high light transmittance can be increased when viewed from above, so that the light emitted from the first light emitting element 20A Since the first covering member 32 facilitates spreading in the X direction and the Y direction, uneven brightness of the light emitting device can be suppressed.

As in the light emitting device 1000 shown in FIGS. 2B and 2C, the thickness of the first covering member 32 in the portion in contact with the first light emitting element 20A is the same as that in the portion spaced apart from the first light emitting element 20A. It may be thicker than the thickness of the member 32. For example, when the first covering member 32 and the second reflecting member 40 are in contact with each other, the thickness of the first covering member 32 in the portion where the first covering member 32 contacts the first light emitting element 20A is the same as that of the second reflecting member 40. It may be thicker than the thickness of the first covering member 32 at the contacting portion. Further, as in a light emitting device 1000A shown in FIG. 3, the upper surface of the first covering member 32 may be made flat. When the thickness of the first covering member 32 at the portion in contact with the first light emitting element 20A is thicker than the thickness of the first covering member 32 at a portion away from the first light emitting element 20A, the first side surface 202A and the first covering This makes it easier to increase the joint area of the member 32. This makes it easier to extract the light from the first light emitting element 20A from the first covering member 32, thereby improving the light extraction efficiency of the light emitting device. When the upper surface of the first covering member is flat, it becomes easier to suppress variations in the shape of the first covering member 32 for each light emitting device. Thereby, the yield of light emitting devices can be improved. The shape of the first covering member 32 can be changed, for example, by adjusting the viscosity of the first covering member and/or the reflective particle-containing member. Note that, in this specification, flatness means that a variation of approximately ±5 μm is allowed.

The light emitting device may include one light emitting element, or as shown in FIG. 2B, the light emitting device may include two light emitting elements, a first light emitting element 20A and a second light emitting element 20B. good. When the light emitting device includes a first light emitting element and a second light emitting element, the first covering member 32 preferably contacts the first light emitting element 20A and the second light emitting element 20B. By doing so, the light from the first light emitting element and the light from the second light emitting element can be guided to the first covering member. For example, when the emission peak wavelengths of the first light emitting element and the second light emitting element are the same, the light from the first light emitting element and the light from the second light emitting element are guided to the first covering member. , reduction in brightness between the first light emitting element and the second light emitting element can be suppressed. Thereby, uneven brightness of the light emitting device can be suppressed. Moreover, when the emission peak wavelengths of the first light emitting element and the second light emitting element are different, the light from the first light emitting element and the light from the second light emitting element are guided to the first covering member. , the color mixing properties of the light emitting device can be improved. Note that in this specification, the expression that the emission peak wavelengths are the same means that a variation of about ±10 nm is allowed.

The first reflective member 31 may or may not be in contact with the first light emitting element 20A. As shown in FIG. 2B, when the first reflective member 31 and the first light emitting element 20A are in contact with each other, it is preferable that the first reflective member 31 directly covers the pair of first electrodes 21A and 22A. . By doing so, it is possible to suppress light from the first light emitting element 20A from being absorbed by the first electrodes 21A and 22A. Further, when the first reflective member 31 and the first light emitting element 20A are in contact with each other, it is preferable that the first reflective member 31 covers the side surface of the first semiconductor layer 23A of the first light emitting element 20A. . By doing so, the thickness of the first reflective member 31 in the Z direction can be increased, so that the first reflective member 31 can easily cover the pair of first electrodes 21A and 22A.

The first reflective member 31 may cover the first electrode forming surface 203A. The first reflective member 31 may directly cover the first electrode forming surface 203A, or may cover the first electrode forming surface 203A via the first covering member 32. By doing so, the light from the first light emitting element 20A is reflected by the first reflecting member 31, so that it is possible to suppress the light from the first light emitting element 20A from being absorbed by the substrate 10. This improves the light extraction efficiency of the light emitting device.

As shown in FIG. 2B, when the light emitting device 1000 includes the first light emitting element 20A and the second light emitting element 20B, the first reflective member 31 covers the first electrode forming surface 203A and the second electrode forming surface 203B. It is preferable. By doing so, the first reflecting member 31 reflects the light from the first light emitting element 20A and the light from the second light emitting element 20B, so the light extraction efficiency of the light emitting device 1000 can be improved. .

When the first reflective member 31 covers the first side surface 202A of the first light emitting element 20A, the length H1 of the contact between the first reflective member 31 and the first side surface 202A in the Z direction is equal to the length H1 of the first side surface 202A in the Z direction. The length is preferably 0.5 times or less, more preferably 0.3 times or less of the length H2. By doing so, the light traveling from the first light emitting element 20A in the X direction and/or the Y direction is less likely to be blocked, so that uneven brightness of the light emitting device can be suppressed.

It is preferable that the maximum thickness of the first reflective member 31 in the Z direction is, for example, 10 μm or more and 200 μm or less. If the maximum thickness of the first reflective member 31 is 10 μm or more, it becomes easier to form the first reflective member 31. Moreover, if the maximum thickness of the first reflective member 31 is 200 μm or less, it becomes easy to form the first reflective member 31 that does not face a part of the first side surface of the first light emitting element 20A described above. By doing so, the light traveling from the first light emitting element 20A in the X direction and/or the Y direction is less likely to be blocked, so that uneven brightness of the light emitting device can be suppressed.

When the light emitting device includes a plurality of light emitting elements, the light emission peak wavelengths of the plurality of light emitting elements may be the same or different. Color reproducibility of the light emitting device can be improved by having different emission peak wavelengths of the plurality of light emitting elements. For example, the emission peak wavelength of the first light emitting element 20A is in the range of 430 nm or more and less than 490 nm (wavelength range in the blue region), and the emission peak wavelength of the second light emitting element 20B is in the range of 490 nm or more and less than 570 nm (wavelength range in the green region). It may be a range. The first light emitting element 20A will be described as an example of the configuration of the light emitting element.

The first light emitting element 20A has a first light extraction surface 201A, a first electrode formation surface 203A on the opposite side of the first light extraction surface, and a space between the first light extraction surface 201A and the first electrode formation surface 203A. It has a certain first side surface 202A. The first side surface 202A may be perpendicular to the first light extraction surface 201A, or may be inclined inwardly or outwardly. A pair of first electrodes 21A and 22A are provided on the first electrode forming surface 203A.

The first light emitting element 20A includes a first element substrate 24A and a first semiconductor layer 23A formed in contact with the first element substrate 24A. The pair of first electrodes 21A and 22A are electrically connected to the first semiconductor layer 23A. Note that in this embodiment, a configuration in which the first light emitting element 20A includes the first element substrate 24A will be described as an example, but the first element substrate 24A may be removed.

The first light emitting element 20A may have a triangular, quadrangular, hexagonal, or other shape when viewed from above. As shown in FIG. 2A, when the light emitting device 1000 includes a first light emitting element 20A and a second light emitting element 20B, and the first light emitting element 20A and the second light emitting element 20B have a rectangular shape when viewed from above, the first It is preferable that one short side 2011A of the first light extraction surface 201A of the light emitting element and one short side 2011B of the second light extraction surface 201B of the second light emitting element are arranged to face each other. By doing so, the light emitting device 1000 can be made thinner in the Y direction.

The first light extraction surface 201A and the second light extraction surface 201B may have substantially the same height or may have different heights in the Z direction. Moreover, in a top view, the areas of the first light extraction surface 201A and the second light extraction surface 201B may be the same or different. Particularly when the light emitting device includes a wavelength conversion member, it is preferable that the light extraction surface of the light emitting element having an emission peak wavelength that easily excites the wavelength conversion member is large. The wavelength conversion member is a member that absorbs at least a portion of the primary light emitted by the light emitting element and emits secondary light having a wavelength different from that of the primary light. For example, the light-emitting device includes a manganese-activated potassium fluorosilicate phosphor (for example, K ₂ SiF ₆ :Mn) which is a wavelength conversion member that emits red light, and the emission peak wavelength of the first light-emitting element is 430 nm or more and less than 490 nm (in the blue region). wavelength range), and when the emission peak wavelength of the second light emitting element is in the range of 490 nm or more and 570 nm or less (wavelength range in the green region), the first light extraction surface 201A of the first light emitting element 20A is It is preferably larger than the second light extraction surface 201B of the second light emitting element 20B. For example, it is preferable that the first light extraction surface 201A of the first light emitting element 20A is 1.2 times or more and twice or less the second light extraction surface 201B of the second light emitting element 20B. A manganese-activated potassium fluorosilicate phosphor (for example, K ₂ SiF ₆ :Mn) is more easily excited by light of 430 nm or more and less than 490 nm than light of 490 nm or more and 570 nm or less. Since the first light extraction surface 201A of the first light emitting element is larger than the second light extraction surface 201B of the second light emitting element, the proportion of light from the first light emitting element 20A can be increased. Even if a part of the light from the first light-emitting element is converted by the manganese-activated fluoride-based phosphor, it is possible to suppress a reduction in the proportion of light from the first light-emitting element emitted from the light-emitting device. Thereby, the color reproducibility of the light emitting device 1000 can be improved.

The second covering member 33 is translucent and covers at least a portion of the first side surface 202A. Since the second covering member 33 covers the first side surface 202A, the light from the first light emitting element 20A can be extracted from the second covering member 33, thereby improving the light extraction efficiency of the light emitting device. The second covering member 33 may directly cover the first side surface 202A, or may cover the first side surface 202A via the first covering member 32. Further, the second covering member 33 may include both a portion that directly covers the first side surface 202A and a portion that covers the first side surface 202A via the first covering member 32. When the refractive index difference between the base material of the first covering member 32 and the first element substrate 24A is smaller than the refractive index difference between the base material of the second covering member 33 and the first element substrate 24A, the second covering member 33 It is preferable that 202A cover the first side surface including the side surface of the first element substrate 24A via the first covering member 32. By doing so, it becomes easier to increase the bonding area between the first covering member 32 and the first element substrate 24A, so it becomes easier to extract light from the first light emitting element from the first covering member 32. When the refractive index difference between the base material of the first covering member 32 and the first semiconductor layer 23A is smaller than the refractive index difference between the base material of the second covering member 33 and the first element substrate 24A, the second covering member 33 It is preferable that the first covering member 32 include a portion 202A that covers the first side surface including the side surface of the first semiconductor layer 23A. By doing so, it becomes easier to extract light from the first light emitting element from the first covering member 32.

As in the light emitting device 1000B shown in FIG. 4, the second covering member 33 may cover the first light extraction surface 201A, and as in the light emitting device 1000 shown in FIG. 2B, the second covering member 33 may cover the first light extraction surface 201A. The surface 201A may be exposed. When the second covering member 33 covers the first light extraction surface 201A, the first light emitting element 20A can be protected from external force from the first light extraction surface 201A. When the first light extraction surface 201A is exposed from the second covering member 33, the thickness of the light emitting device in the Z direction can be reduced, so that the light emitting device can be made smaller.

When the light emitting device includes the second light emitting element 20B, the second covering member 33 preferably covers the first side surface 202A and the second side surface 202B. By doing so, the light from the first light emitting element 20A and the light from the second light emitting element 20B are easily guided to the second covering member 33. For example, when the emission peak wavelengths of the first light emitting element and the second light emitting element are the same, the light from the first light emitting element and the light from the second light emitting element are guided to the second covering member. Luminance unevenness between the first light emitting element and the second light emitting element can be suppressed. Moreover, when the emission peak wavelengths of the first light emitting element and the second light emitting element are different, the light from the first light emitting element and the light from the second light emitting element are guided to the second covering member. The color mixing properties of the light emitting device can be improved. The second covering member may be in contact with the first side surface and/or the second side surface, or may cover the first side surface and/or the second side surface via the first covering member.

The second covering member 33 may contain a wavelength conversion member. By doing so, color adjustment of the light emitting device becomes easy. The wavelength converting member may be uniformly dispersed in the second covering member 33, or the wavelength converting member may be unevenly distributed closer to the first covering member than the upper surface of the second covering member. Examples of the wavelength conversion member contained in the second coating member include a wavelength conversion member that emits green light with an emission peak wavelength of 490 nm or more and 570 nm or less, a wavelength conversion member that emits red light and whose emission peak wavelength is 610 nm or more and 750 nm or less, etc. can be used. The second covering member may contain one type of wavelength conversion member, or may contain a plurality of types. For example, the light guide member may contain a wavelength conversion member that emits green light and a wavelength conversion member that emits red light. Examples of wavelength conversion members that emit green light include β-sialon-based phosphors (for example, Si _6-z Al _z O _z N _8-z :Eu (0<z<4.2). Wavelength conversion members that emit red light Examples of the member include manganese-activated potassium fluorosilicate phosphor (eg, K ₂ SiF ₆ :Mn).

The second reflecting member 40 surrounds the second covering member 33 in a top view and is in contact with the second covering member 33 and the first reflecting member 31. Further, the second reflecting member 40 has a narrow portion 42 in contact with the first reflecting member 31 and a wide portion 41 disposed above the narrow portion 42 in a cross-sectional view. The second reflective member 40 has an inner surface 401 and an outer surface 402. The widths of the narrow portion 42 and the wide portion 41 mean the shortest distance from the inner surface 401 to the outer surface 402.

The second reflecting member 40 is annular in top view. Furthermore, by surrounding the second covering member 33 with the second reflecting member 40, the second reflecting member 40 reflects the light traveling in the X direction and/or the Y direction from the first light emitting element 20A, thereby increasing the light traveling in the Z direction. can be done.

As the second reflective member 40, for example, a known member such as a resin material containing reflective particles in a base material can be used. As a method for forming the second reflective member 40, for example, a notch is formed in the first reflective member 31 and the second covering member 33, and the uncured second reflective member is filled in the notch. The second reflective member may be formed by curing the second reflective member. For example, by using a blade having a narrow portion and a wide portion, a notch formed by the blade may also have a narrow portion and a wide portion. Note that the tip of the blade is the narrow part. By making the tip of the blade narrow, it becomes easier to form the notches in the first reflective member 31 and the second covering member 33 than when using a blade with a constant width.

The narrow portion 42 of the second reflective member 40 contacts the first reflective member 31 . Thereby, it is possible to suppress the light from the first light emitting element 20A from passing through the narrow width part 42 of the second reflection member 40, which is thin. Therefore, the light extraction efficiency of the light emitting device can be improved.

In a top view, the width of the wide portion 41 of the second reflective member 40 is preferably 10 μm or more and 50 μm or less. Since the width of the first reflective member is 50 μm or less, the light emitting device can be miniaturized. Furthermore, by setting the width of the first reflective member to 10 μm or more, it is possible to suppress the light from the first light emitting element from passing through the wide portion 41 of the second reflective member 40 .

The substrate 10 includes a base material 11 and a first wiring 12. The base material 11 has a top surface 111, a bottom surface 112 opposite to the top surface, a back surface 113 adjacent to the top surface 111 and perpendicular to the top surface 111, and a front surface 114 located on the opposite side of the back surface 113. Further, the base material 11 has a side surface 115 between the upper surface 111 and the lower surface 112.

The base material 11 is preferably formed of a material having physical properties close to the coefficient of linear expansion of the first light emitting element 20A, such as an insulating member such as resin or fiber reinforced resin, ceramics, or glass. It will be done. As the resin or fiber reinforced resin, for example, epoxy, glass epoxy, bismaleimide triazine (BT), polyimide, etc. can be used, and as the ceramic, for example, aluminum oxide, aluminum nitride, zirconium oxide, zirconium nitride, zirconium oxide, etc. can be used. Titanium, titanium nitride, a mixture thereof, or the like can be used.
From the viewpoint of strength, the lower limit of the thickness of the base material 11 is preferably 0.05 mm or more, and more preferably 0.2 mm or more. Moreover, from the viewpoint of the thickness (depth) of the light emitting device in the Z direction, the upper limit value of the thickness of the base material 11 is preferably 0.5 mm or less, and more preferably 0.4 mm or less.

As shown in FIG. 2B, the substrate 10 may include a second wiring 13 arranged on the lower surface 112. When the substrate 10 includes the first wiring 12 and the second wiring 13, the substrate 10 may include a via 15 that connects the first wiring 12 and the second wiring 13. It is preferable that the via 15 has a circular shape when viewed from above. By doing so, it can be easily formed using a drill or the like. When the via 15 is circular in top view, the diameter of the via is preferably 100 μm or more and 150 μm or less. When the diameter of the via is 100 μm or more, the heat dissipation of the light emitting device is improved, and when the diameter of the via is 150 μm or less, a decrease in the strength of the base material is reduced. In this specification, a circular shape includes not only a perfect circle but also a shape close to this (for example, an elliptical shape or a shape where the four corners of a quadrilateral are chamfered into large arcs).

The via 15 may be formed by filling a conductive material into the through hole of the base material 11, and as shown in FIG. A filling member 152 filled in a region surrounded by the fourth wiring 151 may also be provided. Filling member 152 may be conductive or insulating. It is preferable to use a resin material for the filling member 152. In general, a resin material before hardening has higher fluidity than a metal material before hardening, so it is easier to fill the fourth wiring 151. Therefore, by using a resin material for the filling member, manufacturing of the substrate becomes easier. Examples of resin materials that are easy to fill include epoxy resin. When using a resin material as the filling member, it is preferable to include an additive member in order to lower the coefficient of linear expansion. By doing so, the difference in linear expansion coefficient with the fourth wiring becomes small, so it is possible to suppress the formation of a gap between the fourth wiring and the filling member due to heat from the light emitting element. Examples of the additive include silicon oxide. Moreover, when a metal material is used for the filling member 152, heat dissipation can be improved. Further, when the via 15 is configured by filling a through hole of the base material with a conductive material, it is preferable to use a metal material such as Ag or Cu having high thermal conductivity.

As shown in FIG. 2B, the first wiring 12 preferably includes a convex portion 121 at a position corresponding to the pair of first electrodes 21A and 22A of the first light emitting element 20A. In other words, it is preferable that the first wiring 12 includes a convex portion 121 at a position overlapping the first electrodes 21A and 22A when viewed from above. By providing the first wiring 12 with the convex portion 121, when the first wiring 12 and the first electrodes 21A, 22A are connected via the conductive adhesive member 60, a self-alignment effect occurs between the first light emitting element and the substrate. It is possible to easily align the position with the The thickness of the convex portion 121 in the Z direction is preferably 10 μm or more and 30 μm or less. The width of the convex portion 121 in the X direction and/or the Y direction may be changed as appropriate depending on the size of the electrode of the opposing light emitting element.

The conductive adhesive member 60 is a member that electrically connects the first wiring 12 to the pair of first electrodes 21A and 22A provided on the first light emitting element 20A. Examples of the material of the conductive adhesive member 60 include bumps made of gold, silver, copper, etc., metal pastes containing metal powders such as silver, gold, copper, platinum, aluminum, palladium, and resin binders, tin-bismuth, tin, etc. - Known materials such as copper-based, tin-silver-based, gold-tin-based solders, and brazing materials such as low-melting point metals can be used.

When the light emitting device includes the second light emitting element 20B, the first wiring 12 preferably includes a convex portion 121 at a position corresponding to the pair of electrodes 21B and 22B of the second light emitting element. By doing so, the light emitting element and the substrate can be easily aligned due to the self-alignment effect.

The base material 11 may be provided with a recess 16 that opens to the lower surface 112 of the base material and the back surface 113 of the base material, or may not be provided with the recess 16. When the recess 16 is provided, the bonding strength between the light emitting device 1000A and the mounting board can be improved. Even if the light emitting device 1000 is a top-emitting type (top view type) in which the lower surface 112 of the base material 11 and the mounting board are mounted facing each other, the light emitting device 1000 may be mounted with the back surface 113 of the base material 11 facing the mounting board. Even in the side-emitting type (side view type), the bonding strength with the mounting board can be improved by increasing the volume of the bonding member. The bonding strength between the light emitting device 1000 and the mounting board can be improved especially in the case of a side-emitting type. The number of depressions in the base material may be one or more. By having a plurality of depressions, it is possible to further improve the bonding strength between the light emitting device 1000 and the mounting board.

The maximum depth of each of the depressions 16 in the Z direction is preferably 0.4 to 0.9 times the thickness of the base material 11 in the Z direction. When the depth of the recess is deeper than 0.4 times the thickness of the base material, the volume of the bonding member formed in the recess increases, so that the bonding strength between the light emitting device and the mounting board can be improved. By making the depth of the depression shallower than 0.9 times the thickness of the base material, it is possible to suppress a decrease in the strength of the base material.

As in the light emitting device 1000 shown in FIG. 2B, the upper surface 111 of the base material 11 may have a recess 118, and as in the light emitting device 1000C shown in FIG. It does not have to have. When the upper surface 111 of the base material 11 has a recess 118 , it is preferable that a portion of the second reflective member 40 be disposed within the recess 118 . By doing so, the base material 11 and the second reflective member 40 are in contact with each other, so that the bonding strength between the base material and the second reflective member is improved. The recess 118 formed on the upper surface 111 of the base material 11 is preferably formed so as to surround the outer periphery of the upper surface 111 of the base material 11, as shown in FIG. By doing so, the area where the base material 11 and the second reflective member 40 are in contact increases, so that the bonding strength between the base material and the second reflective member is improved.

It is preferable that the outer edge of the base material and the outer surface 402 of the second reflective member are flush with each other as in the light emitting device 1000 shown in FIGS. 7, 8, and 9. By doing so, the light emitting device can be downsized in the X direction and/or the Y direction.

The light emitting device 1000 may include an insulating film 18 covering a portion of the second wiring 13. By providing the insulating film 18, insulation on the lower surface 112 can be ensured and short circuits can be prevented. Moreover, peeling of the second wiring 13 from the base material 11 can be prevented.

The light emitting device may include a translucent member 50 covering the first light extraction surface. By covering the first light extraction surface 201A of the first light emitting element with the translucent member 50, the first light emitting element 20A can be protected from external stress. The translucent member 50 may be in contact with and cover the first light extraction surface, or may be coated on the first light extraction surface with a translucent adhesive layer 34 interposed therebetween, as shown in FIG. 2B. good. When the light emitting device includes the second light emitting element 20B, one translucent member 50 may cover the first light extraction surface 201A and the second light extraction surface 201B. Further, the light emitting device may include a plurality of light-transmitting members. For example, a light-emitting device includes a first light-transmitting member and a second light-transmitting member, the first light-transmitting member covers the first light extraction surface, and the second light-transmitting member covers the second light extraction surface. It may be covered. When the first light extraction surface 201A and the second light extraction surface 201B are covered with one light-transmitting member 50, the light from the first light-emitting element and the light from the second light-emitting element are covered by the light-transmitting member 50. By being guided by the light, reduction in brightness between the first light emitting element and the second light emitting element can be suppressed. Thereby, uneven brightness of the light emitting device can be suppressed.

When the light emitting device includes the light-transmitting member 50, the side surface of the light-transmitting member is preferably covered with a second reflective member. By doing so, it is possible to provide a light-emitting device with a high contrast between the light-emitting region and the non-light-emitting region, and with good "parting performance".

The translucent member 50 may contain a wavelength conversion member. By doing so, color adjustment of the light emitting device becomes easy. The emission peak wavelength of the wavelength conversion member contained in the translucent member is preferably 610 nm or more and 750 nm or less (wavelength range in the red region). For example, since the emission peak wavelength of the first light emitting element is in the wavelength range of the blue region and the emission peak wavelength of the second light emitting element is in the wavelength range of the green region, the emission peak of the wavelength conversion member contained in the translucent member When the wavelength is in the red wavelength range, the color reproducibility of the light emitting device is improved. The light-transmitting member may contain one type of wavelength conversion member, or may contain a plurality of types. For example, the translucent member may contain a wavelength conversion member that emits green light and a wavelength conversion member that emits red light. By including the wavelength conversion member in which the light-transmitting member emits green light, color adjustment of the light-emitting device becomes easy. Examples of wavelength conversion members that emit green light include β-sialon-based phosphors (for example, Si _6-z Al _z O _z N _8-z :Eu (0<z<4.2). Wavelength conversion members that emit red light Examples of the member include manganese-activated potassium fluorosilicate phosphor (eg, K ₂ SiF ₆ :Mn).

The wavelength conversion member may be uniformly dispersed in the transparent member, or the wavelength conversion member may be unevenly distributed closer to the first light emitting element than the upper surface of the transparent member. By unevenly distributing the wavelength conversion member closer to the first light emitting element than the upper surface of the translucent member, the base material of the translucent member also functions as a protective layer even if a wavelength conversion member that is sensitive to moisture is used. Therefore, deterioration of the wavelength conversion member can be suppressed. Like the light-emitting device 1000 shown in FIG. 2B, the light-transmitting member 50 may include a layer 51 containing a wavelength conversion member and a layer 52 that does not substantially contain the wavelength conversion member. In the Z direction, the layer that does not substantially contain the wavelength conversion member is located above the layer that contains the wavelength conversion member. By doing so, the layer that does not substantially contain the wavelength conversion member also functions as a protective layer, so that deterioration of the wavelength conversion member can be suppressed. Examples of wavelength conversion members that are sensitive to moisture include manganese-activated potassium fluorosilicate phosphors. A manganese-activated potassium fluorosilicate phosphor is a preferable member from the viewpoint of color reproducibility because it can emit light with a relatively narrow spectral line width. "Substantially no wavelength conversion member is contained" means that the wavelength conversion member that is unavoidably mixed is not excluded, and the content of the wavelength conversion member is preferably 0.05% by weight or less.

The layer 51 containing the wavelength conversion member of the transparent member 50 may be a single layer or may be a plurality of layers. For example, like a light emitting device 1000A shown in FIG. 3, the transparent member 50 may include a first wavelength conversion layer 51A and a second wavelength conversion layer 51B covering the first wavelength conversion layer 51A. good. The second wavelength conversion layer 51B may directly cover the first wavelength conversion layer 51A, or may cover the first wavelength conversion layer 51A via another transparent layer. Note that the first wavelength conversion layer 51A is arranged closer to the first light extraction surface 201A of the first light emitting element 20A than the second wavelength conversion layer 51B. It is preferable that the emission peak wavelength of the wavelength conversion member contained in the first wavelength conversion layer 51A is shorter than the emission peak wavelength of the wavelength conversion member contained in the second wavelength conversion layer 51B. By doing so, the wavelength conversion member of the second wavelength conversion layer 51B can be excited by the light from the first wavelength conversion layer 51A excited by the first light emitting element. Thereby, the light from the wavelength conversion member of the second wavelength conversion layer 51B can be increased.

The emission peak wavelength of the wavelength conversion member contained in the first wavelength conversion layer 51A is 500 nm or more and 570 nm or less, and the emission peak wavelength of the wavelength conversion member contained in the second wavelength conversion layer 51B is 610 nm or more and 750 nm or less. It is preferable that there be. By doing so, a light emitting device with high color reproducibility can be obtained. For example, the wavelength conversion member contained in the first wavelength conversion layer 51A may be a β-sialon-based phosphor, and the wavelength conversion member contained in the second wavelength conversion layer 51B may be a manganese-activated potassium fluorosilicate phosphor. It will be done. In particular, when a manganese-activated potassium fluorosilicate phosphor is used as the wavelength conversion member contained in the second wavelength conversion layer 51B, the light-transmitting member 50 is connected to the first wavelength conversion layer 51A and the second wavelength conversion layer. It is preferable to include a layer 51B. Although the manganese-activated potassium fluorosilicate phosphor tends to cause brightness saturation, the position of the first wavelength conversion layer 51A between the second wavelength conversion layer 51B and the first light emitting element 20A reduces the amount of light emitted from the first light emitting element. It is possible to suppress excessive irradiation of the manganese-activated potassium fluorosilicate phosphor with light. Thereby, deterioration of the manganese-activated potassium fluorosilicate phosphor can be suppressed.

<Embodiment 2>
A light emitting device 2000 according to Embodiment 2 of the present invention will be described based on FIG. 10. The light emitting device 2000 differs from the light emitting device 1000 according to the first embodiment in the number of light emitting elements.

As shown in FIG. 10, the light emitting device 2000 includes a first light emitting element 20A, a second light emitting element 20B, and a third light emitting element 20C. The first light emitting element 20A, the second light emitting element 20B, and/or the third light emitting element may have the same emission peak wavelength, or may have different emission peak wavelengths. Note that the light emitting device may include four or more light emitting elements.

In the X direction, when the first light emitting element 20A, the second light emitting element 20B, and the third light emitting element 20C are lined up in this order, the emission peak wavelength of the first light emitting element 20A and the third light emitting element 20C are different. It is preferable that the emission peak wavelength is the same. By doing so, for example, when the output of the first light emitting element 20A is insufficient, it can be supplemented by the third light emitting element 20C. Further, a second light emitting element 20B having a light emission peak wavelength different from the light emission peak wavelength of the first light emitting element 20A and the light emission peak wavelength of the third light emitting element 20C is located between the first light emitting element 20A and the third light emitting element 20C. By doing so, color unevenness can be reduced more than when the first light emitting element 20A, the third light emitting element 20C, and the second light emitting element 20B are lined up in this order. For example, the light emitting device includes a first light emitting element whose emission peak wavelength is in the range of 430 nm or more and less than 490 nm (wavelength range in the blue region), and a first light emitting element whose emission peak wavelength is in the range of 490 nm or more and less than 570 nm (wavelength range in the green region). The third light emitting element may include a second light emitting element and a third light emitting element having an emission peak wavelength in a range of 430 nm or more and less than 490 nm (wavelength range of blue region).

Each component in a light emitting device according to an embodiment of the present invention will be described below.

(Substrate 10)
The substrate 10 is a member on which a light emitting element is placed. The substrate 10 includes a base material 11 and a first wiring 12.

(Base material 11)
The base material 11 can be constructed using an insulating member such as resin or fiber-reinforced resin, ceramics, or glass. Examples of the resin or fiber-reinforced resin include epoxy, glass epoxy, bismaleimide triazine (BT), and polyimide. Further, the base material 11 may contain a white pigment such as titanium oxide. Examples of ceramics include aluminum oxide, aluminum nitride, zirconium oxide, zirconium nitride, titanium oxide, titanium nitride, and mixtures thereof. Among these base materials, it is particularly preferable to use a base material having physical properties close to the coefficient of linear expansion of the light emitting element.

(First wiring 12)
The first wiring is arranged on the upper surface of the base material and electrically connected to the light emitting element. The first wiring can be formed of copper, iron, nickel, tungsten, chromium, aluminum, silver, gold, titanium, palladium, rhodium, or an alloy thereof. It may be a single layer or multiple layers of these metals or alloys. In particular, copper or a copper alloy is preferable from the viewpoint of heat dissipation. Further, a layer of silver, platinum, aluminum, rhodium, gold, or an alloy thereof may be provided on the surface layer of the first wiring from the viewpoint of wettability of the conductive adhesive member and/or light reflectivity. good.

(Second wiring 13, third wiring 14)
The second wiring is arranged on the lower surface of the substrate. The third wiring covers the inner wall of the recess and is electrically connected to the second wiring. The second wiring and the third wiring can use the same conductive member as the first wiring.

(Via 15)
The via 15 is provided in a hole penetrating the upper surface 111 and the lower surface 112 of the base material 11, and is a member that electrically connects the first wiring and the second wiring. The via 15 may include a fourth wiring 151 that covers the surface of the through hole of the base material, and a filling member 152 filled in the fourth wiring 151. For the fourth wiring 151, the same conductive member as the first wiring, the second wiring, and the third wiring can be used. The filling member 152 may be a conductive member or an insulating member.

(Insulating film 18)
The insulating film 18 is a member that ensures insulation on the lower surface and prevents short circuits. The insulating film may be formed of any material used in the field. Examples include thermosetting resins and thermoplastic resins.

(First light emitting element 20A, second light emitting element 20B, third light emitting element 20C)
The first light emitting element, the second light emitting element, and the third light emitting element are semiconductor elements that emit light by themselves when a voltage is applied, and known semiconductor elements made of nitride semiconductors or the like can be used. Examples of the first light emitting element, the second light emitting element, and the third light emitting element include LED chips. The first light emitting element, the second light emitting element, and the third light emitting element each include at least a semiconductor layer, and in many cases further include an element substrate. The first light emitting element, the second light emitting element, and the third light emitting element have positive and negative electrodes. The positive and negative electrodes can be made of gold, silver, tin, platinum, rhodium, titanium, aluminum, tungsten, palladium, nickel, or an alloy thereof. It is preferable to use a nitride semiconductor as the semiconductor material. Nitride semiconductors are mainly represented by the general formula In _x Al _y Ga _1-xy N (0≦x, 0≦y, x+y≦1). In addition, InAlGaAs-based semiconductors, InAlGaP-based semiconductors, zinc sulfide, zinc selenide, silicon carbide, etc. can also be used. The element substrates of the first light emitting element, the second light emitting element, and the third light emitting element are mainly crystal growth substrates capable of growing semiconductor crystals constituting the semiconductor stack, but the semiconductor elements separated from the crystal growth substrate It may also be a bonding substrate to be bonded to a structure. Since the element substrate has light-transmitting properties, flip-chip mounting can be easily adopted and light extraction efficiency can be easily increased. Examples of the base material of the element substrate include sapphire, gallium nitride, aluminum nitride, silicon, silicon carbide, gallium arsenide, gallium phosphorus, indium phosphorus, zinc sulfide, zinc oxide, zinc selenide, and diamond. Among them, sapphire is preferred. The thickness of the element substrate can be selected as appropriate, and is, for example, 0.02 mm or more and 1 mm or less, and preferably 0.05 mm or more and 0.3 mm or less from the viewpoint of the strength of the element substrate and/or the thickness of the light emitting device. .

(First reflective member)
The first reflective member is a member that suppresses light from the first light emitting element from being absorbed by the substrate. The first reflective member covers the upper surface of the base material and reflects light from the first light emitting element. From the viewpoint of light extraction efficiency of the light emitting device, the light reflectance of the first reflecting member at the emission peak wavelength of the first light emitting element is preferably 70% or more, more preferably 80% or more, and 90%. It is even more preferable that the above is the case. The first reflective member contains reflective particles in the base material.

(Base material of first reflective member)
A resin can be used for the base material of the first reflective member, and examples thereof include silicone resin, epoxy resin, phenol resin, polycarbonate resin, acrylic resin, or modified resins thereof. Among them, silicone resins and modified silicone resins are preferable because they have excellent heat resistance and light resistance. Specific silicone resins include dimethyl silicone resin, phenyl-methyl silicone resin, and diphenyl silicone resin.

(reflective particles)
The reflective particles include titanium oxide, zinc oxide, magnesium oxide, magnesium carbonate, magnesium hydroxide, calcium carbonate, calcium hydroxide, calcium silicate, magnesium silicate, barium titanate, barium sulfate, aluminum hydroxide, aluminum oxide, zirconium oxide, One kind of silicon oxide can be used alone, or two or more kinds of these can be used in combination. For example, as the reflective particles, titanium oxide whose surface is coated with a known member such as zirconia may be used. The shape of the reflective particles can be selected as appropriate and may be amorphous or crushed, but spherical is preferred from the viewpoint of fluidity. Further, the particle size of the reflective particles is, for example, about 0.1 μm or more and 0.5 μm or less, but the smaller the particle size, the more preferable it is in order to enhance the light reflection and coating effects. The content of reflective particles in the light reflective member can be selected as appropriate, but from the viewpoint of light reflectivity and viscosity in liquid state, it is preferably 10 wt% or more and 80 wt% or less, and 20 wt% or more and 70 wt% or less. More preferably, 30 wt% or more and 60 wt% or less is even more preferable.

(First covering member)
The first covering member is a translucent member that exposes the first light extraction surface and covers at least a portion of the first reflective member and the first side surface. As the first covering member, a translucent member can be used, and for example, resin can be used. Examples of resins that can be used for the first covering member include silicone resins, epoxy resins, phenol resins, polycarbonate resins, acrylic resins, and modified resins thereof. Among them, silicone resins and modified silicone resins are preferable because they have excellent heat resistance and light resistance.

The first covering member may contain various types of diffusion particles. Examples of the diffusion particles include silicon oxide, aluminum oxide, zirconium oxide, and zinc oxide. As the diffusion particles, one of these types can be used alone, or two or more of these types can be used in combination. Particularly preferred is silicon oxide, which has a small coefficient of thermal expansion. Further, by using nanoparticles as the diffusion particles, scattering of light emitted by the light emitting element can be increased, and the amount of wavelength conversion member used can also be reduced. Note that nanoparticles are particles with a particle size of 1 nm or more and 100 nm or less. Moreover, the "particle size" in this specification is defined, for example, by _D50 .

(Reflective particle containing member)
The reflective particle-containing member is a member that contains reflective particles in a translucent member. The reflective particle-containing member may include a reflective part in which reflective particles are unevenly distributed, and a transparent part located above the reflective part and in which reflective particles are not unevenly distributed.

As the base material of the reflective particle-containing member, the same material as the first covering member can be used. Further, as the reflective particles of the reflective particle-containing member, the same material as the reflective particles of the first reflective member can be used.

(Second covering member)
The second covering member is a member that covers at least a portion of the first side surface. As the base material of the second covering member, the same material as the first covering member can be used.

(Second reflective member)
The second reflective member is a member surrounding the second covering member in a top view. The second reflective member can be made of the same material as the first reflective member.

(Translucent member 50)
The light-transmitting member is a member that covers the first light extraction surface and protects the first light emitting element. As the base material of the translucent member, the same material as the first covering member can be used.

(Adhesive layer 34)
The adhesive layer is a member that adheres the light-transmitting member and the first light extraction surface of the first light emitting element. When the first light extraction surface is covered with the second covering member, the adhesive layer is a member that adheres the light-transmitting member and the second covering member. The adhesive layer has translucency. The same material as the first covering member can be used for the adhesive layer.

(Wavelength conversion member)
The wavelength conversion member absorbs at least a portion of the primary light emitted by the light emitting element and emits secondary light having a wavelength different from that of the primary light. As the wavelength conversion member, one type of the specific examples shown below can be used alone or two or more types can be used in combination. When the translucent member includes a plurality of wavelength conversion layers, the wavelength conversion members contained in each wavelength conversion layer may be the same or different.

As wavelength conversion members that emit green light, yttrium-aluminum-garnet-based phosphors (e.g., Y ₃ (Al, Ga) ₅ O ₁₂ :Ce), lutetium-aluminum-garnet-based phosphors (e.g., Lu ₃ (Al, Ga)) are used. ₅ O ₁₂ :Ce), terbium-aluminum-garnet-based phosphor (e.g. Tb ₃ (Al, Ga) ₅ O ₁₂ :Ce)-based phosphor, silicate-based phosphor (e.g. (Ba, Sr) ₂ SiO ₄ :Eu) ), chlorosilicate phosphors (e.g. Ca ₈ Mg(SiO ₄ ) ₄ Cl ₂ :Eu), β-sialon phosphors (e.g. Si _6-z Al _z O _z N _8-z :Eu (0<z<4 .2)), SGS-based phosphors (for example, SrGa ₂ S ₄ :Eu), alkaline earth aluminate-based phosphors (Ba,Sr,Ca)Mg _x Al ₁₀ O _17-x :Eu,Mn, etc. . As a wavelength conversion member for yellow light emission, an α-sialon-based phosphor (for example, M _z (Si, Al) ₁₂ (O, N) ₁₆ (0<z≦2, and M is Li, Mg, Ca, Y , and lanthanide elements excluding La and Ce).In addition, among the wavelength conversion members that emit green light, there are also wavelength conversion members that emit yellow light.For example, yttrium-aluminum-garnet-based phosphors include By substituting a part of Y with Gd, the emission peak wavelength can be shifted to the longer wavelength side, making it possible to emit yellow light.Also, among these, there are also wavelength conversion members capable of emitting orange light. Examples of wavelength conversion members that emit red light include nitrogen-containing calcium aluminosilicate (CASN or SCASN)-based phosphors (e.g. (Sr,Ca)AlSiN ₃ :Eu).In addition, manganese-activated fluoride-based phosphors It is a phosphor represented by the general formula (I) A ₂ [M _1-a Mn _a F ₆ ] (However, in the above general formula (I), A is K, Li, Na, Rb, Cs and _NH4 , M is at least one element selected from the group consisting of Group 4 elements and Group 14 elements, and a is 0<a<0.2 A representative example of this manganese-activated fluoride-based phosphor is a manganese-activated potassium fluorosilicate phosphor (for example, K ₂ SiF ₆ :Mn).

(Method for manufacturing light emitting device 1000)
Next, an example of a method for manufacturing the light emitting device according to the embodiment will be described based on FIGS. 11 to 18.

[Step of preparing the substrate and first light emitting element]
First, a substrate and a first light emitting element are prepared. The substrate includes a base material having an upper surface and a first wiring arranged on the upper surface. The first light emitting element includes a first light extraction surface, a first electrode formation surface opposite to the first light extraction surface, and a first side surface between the first light extraction surface and the first electrode formation surface. , a pair of first electrodes on the first electrode forming surface. When the light emitting device includes a plurality of light emitting elements, the plurality of light emitting elements are prepared. Either the step of preparing the substrate or the step of preparing the light emitting element may be performed first. Further, the substrate may be separated into individual pieces for each light emitting device, or may be in the state of a collective substrate before being separated into pieces.

[Step of placing the first light emitting element]
As shown in FIG. 11, the first light emitting element 20A is placed on the first wiring 12 with the first electrode forming surface 203A of the first light emitting element 20A and the first wiring 12 of the substrate 10 facing each other. The first wiring 12 and the first electrodes 21A and 22A can be bonded together using the conductive adhesive member 60. When the light emitting device includes the second light emitting element 20B, the second electrode forming surface 203B of the second light emitting element 20B and the first wiring 12 of the substrate 10 are made to face each other, and the second light emitting element is placed on the first wiring 12. Place 20B.

[Step of arranging reflective particle-containing member]
As shown in FIG. 12, the reflective particle-containing member 30 is arranged on the upper surface 111 of the base material 11 so that at least a part of the upper surface 111 of the base material 11 overlapping with the first light emitting element 20A is exposed when viewed from above. By forming a reflective particle-containing member in which at least a portion of the upper surface of the base material that overlaps with the first light-emitting element is exposed when viewed from above, a reflective particle-containing member that does not expose the upper surface of the base material that overlaps with the first light-emitting element is formed. It becomes easier to reduce the amount of the reflective particle-containing member than in the case where the reflective particle-containing member is used. Thereby, it is possible to prevent the reflective particle-containing member from being formed on the first light extraction surface of the first light emitting element even after the step of spreading the reflective particle-containing member using centrifugal force, which will be described later. This makes it easier to extract light from the first light emitting element, thereby improving the light extraction efficiency of the light emitting device.

The reflective particle-containing member 30 may be placed in contact with the first side surface 202A of the first light emitting element 20A, or may be placed apart from the first side surface 202A of the first light emitting element 20A. It is preferable that the reflective particle-containing member 30 is arranged so as to be spaced apart from at least a portion of the first side surface 202A. By doing so, it is possible to prevent the reflective particle-containing member from being formed on the first light extraction surface of the first light emitting element even after the step of spreading the reflective particle-containing member by centrifugal force, which will be described later. Further, the entire surface of the first side surface may be arranged so as to be spaced apart from the reflective particle-containing member.

As the reflective particle-containing member 30, a one-component curable resin or a two-component curable resin may be used. When using a two-component curable resin, it is preferable to mix the main ingredient of the two-component curable resin material and reflective particles, and then mix the curing agent after a certain period of time has passed. By doing so, air between the reflective particles and the main material can be removed. This makes it easier for the reflective particles to settle when a centrifugal force, which will be described later, is applied. Examples of the two-component curable resin material include silicone resin, modified silicone resin, epoxy resin, and modified epoxy resin. The time elapsed after mixing the main ingredient of the two-component curable resin material and the reflective particles is preferably 2 hours or more, from the viewpoint of making it easier for the reflective particles to settle. Further, the elapsed time is preferably 8 hours or less from the viewpoint of shortening the manufacturing time. Note that after mixing the curing agent, the process moves to a step of spreading the reflective particle-containing member using centrifugal force before the reflective particle-containing member is cured.

[Step of spreading reflective particle-containing member by centrifugal force]
The reflective particle-containing member 30 is spread by centrifugal force on the upper surface 111 of the base material 11 overlapping with the first light emitting element 20A. As shown in FIG. 13, the intermediate body 100 including the substrate 10 and the reflective particle-containing member 30 is centrifugally rotated in a direction in which centrifugal force is applied to the upper surface 111 of the base material 11. Note that the intermediate body 100 shown in FIG. 13 is a simplified drawing, and the intermediate body 100 may include a plurality of first light emitting elements and/or second light emitting elements. In the case of centrifugal rotation, the intermediate body 100 is centrifugally rotated about the rotation axis 80 in which the upper surface 111 of the base material is located inside the lower surface 112 of the base material. In other words, the rotating shaft 80 is located on the upper surface side of the intermediate body 100, and the intermediate body 100 is moved in the direction A in which it revolves around the rotating shaft 80. Note that the B direction in FIG. 13 is a direction parallel to the upper surface 111 of the base material. By applying centrifugal force to the reflective particle-containing member 30, the reflective particle-containing member 30 is expanded, and as shown in FIG. Can be coated. This makes it possible to suppress light from the first light emitting element from being absorbed by the substrate, thereby improving the light extraction efficiency of the light emitting device. At least a portion of the upper surface 111 of the base that was exposed from the reflective particle-containing member may be covered with the reflective particle-containing member 30, and the entire upper surface of the base that overlaps with the first light emitting element may be covered with the reflective particle-containing member 30. May be coated. By covering the entire upper surface of the base material that overlaps with the first light emitting element with the reflective particle-containing member 30, it is possible to further suppress light from the first light emitting element from being absorbed by the substrate.

Furthermore, by forcibly settling the reflective particles of the reflective particle-containing member 30 in the Z-direction using centrifugal force, as shown in FIG. It is possible to form a first coating member 32 that is located on the first reflective member 31 and has a lower concentration of reflective particles than the first reflective member. The first side surface 202A of the first light emitting element 20A is covered with the first covering member 32, thereby improving the light extraction efficiency of the light emitting device. The Z+ direction on the Z axis is the direction from the lower surface 112 of the base material 11 toward the upper surface 111 of the base material 11, and the opposite direction to the Z+ direction is the Z- direction. The rotation speed and number of rotations when centrifugally rotating the intermediate body 100 depend on the content and particle size of reflective particles, but if the number of rotations and rotation radius are adjusted so that a centrifugal force of 200 x g or more is applied, for example. good.

Note that the intermediate body 100 may be singulated for each light emitting device, or may be in the state of a collective substrate before being singulated. When the intermediate body is a collective substrate, the planar area of the intermediate body becomes large. When the planar area of the intermediate body is large, the difference in the way centrifugal force is applied between the center of the intermediate body 100 and a position away from the center of the intermediate body 100 tends to be large. For this reason, there is a possibility that the shape of the reflective particle-containing member of each light emitting device located at the center of the intermediate body 100 and at a position away from the center of the intermediate body 100 will vary in shape. This variation in the shape of the reflective particle-containing member can be suppressed by increasing the radius of rotation. Specifically, by setting the radius of rotation to be 70 times or more the length of the intermediate body 100 arranged in the rotation direction, it is possible to suppress variations in the shape of the reflective particle-containing member. Note that if the intermediate body has flexibility to bend along the circumference of the rotation radius due to centrifugal force, the difference in distance from the rotation axis 80 can be reduced.

When curing the reflective particle-containing member 30, it is preferable to harden the reflective particle-containing member while applying centrifugal force to the reflective particle-containing member. It is preferable to use reflective particles with a small particle size from the viewpoint of light reflection, but the smaller the particle size, the more difficult it is to settle. By using centrifugal force, reflective particles can be caused to settle in the Z-direction. In order to cure the reflective particles in a precipitated state, it is preferable to perform the curing process of the reflective particle-containing member while applying centrifugal force, that is, while rotating the intermediate body 100. By doing so, it is possible to suppress the reflective particles from moving in the Z+ direction within the reflective particle-containing member.

The temperature at which the reflective particle-containing member is cured is 40°C or higher and 200°C or lower. By increasing the curing temperature, the time for curing the reflective particle-containing member can be shortened and it is efficient. Furthermore, considering that the metal of the centrifugal sedimentation device expands due to heat and the position of the rotating shaft 80 moves, it is preferable that the curing temperature be as low as possible. That is, the temperature at which the reflective particle-containing member is cured is preferably 50° C. or higher from the viewpoint of efficiency. Further, the temperature at which the reflective particle-containing member is cured is preferably 60° C. or lower, taking into consideration the movement of the rotating shaft 80. When curing at 80° C. or higher, it is preferable to adjust the device so that at least the metal part of the centrifugal rotation device does not reach 80° C. or higher. As the resin material constituting the reflective particle-containing member, it is preferable to select a resin material that can be at least temporarily cured by keeping the rotating intermediate body at a temperature of 40° C. or higher. Examples of methods for curing the reflective particle-containing member while causing the reflective particles to settle include applying hot air, using a panel heater, and the like.

[Step of forming second covering member]
As shown in FIG. 15, a second covering member 33 that covers the reflective particle-containing member 30 is formed. The second covering member 33 covers at least a portion of the first side surface 202A of the first light emitting element 20A. The second covering member 33 may cover the first light extraction surface 201 of the first light emitting element 20A, or may expose the first light extraction surface 201. In this step, the second coating member 33 is formed, for example, by dropping a liquid resin material containing a base material and a wavelength conversion member onto the reflective particle-containing member 30. As another method of forming, for example, the second coating member 33 may be formed by depositing the wavelength conversion member on the reflective particle-containing member 30 by a spray method, an electrodeposition method, etc., and then dropping the base material. It is formed by impregnating it with phosphor and solidifying it. The wavelength conversion member may be unevenly distributed in a portion of the second covering member, or may be uniformly dispersed within the second covering member.

[Step of forming a translucent member]
As shown in FIG. 16, a translucent member 50 is formed to cover the first light extraction surface 201A of the first light emitting element 20A. The light-transmitting member may be prepared in advance and placed on the first light-extracting surface 201A to form a light-transmitting member covering the first light-extracting surface 201A. A translucent member may be formed by a known method such as potting so as to cover the extraction surface 201A. When a translucent member is disposed on the first light extraction surface 201A, the first light extraction surface 201A may be covered with a translucent adhesive layer 34.

[Process of forming a notch]
As shown in FIG. 17, a notch 70 is formed that penetrates the second covering member 33 and contacts at least the reflective particle-containing member 30. As shown in FIG. The cutout 70 is formed to surround the first light emitting element 20A when viewed from above. When the light emitting device includes the second light emitting element 20B, the cutout 70 is formed to surround the first light emitting element 20A and the second light emitting element 20B when viewed from above. When the reflective particle-containing member 30 includes a first reflective member 31 in which reflective particles are unevenly distributed, and a first covering member 32 that is located on the first reflective member 31 and has a lower concentration of reflective particles than the first reflective member. , the notch 70 penetrates through the first reflective member 32 and the second covering member 33 and is in contact with at least the first reflective member 31 . The cutout 70 may or may not penetrate the first reflective member 31. Moreover, when the notch 70 penetrates the first reflective member 31, the notch 70 and the upper surface 111 of the base material may be in contact with each other. The notch in the upper surface 111 of the base material 11 is also called a recess 118. When the light emitting device includes the translucent member 50, the cutout 70 is formed to penetrate the translucent member 50. For example, the notch can be formed by a known method such as a blade dicing method or a laser dicing method. Note that in this specification, a notch formed by etching is also referred to as a notch. Further, the notch has a narrow part and a wide part, with the narrow part located on the Z- direction side and the wide part located on the Z+ direction side. The narrow part and the wide part can be formed by the shape of the blade, etc.

[Step of forming the second reflective member]
As shown in FIG. 18, a second reflective member 40 that is in contact with the second covering member 33 and the reflective particle-containing member 30 is formed. The second reflective member 40 surrounds the first light emitting element 20A when viewed from above. When the light emitting device includes the second light emitting element 20B, the second reflecting member 40 surrounds the first light emitting element 20A and the second light emitting element 20B when viewed from above. The second reflecting member 40 can be formed by filling the notch 70 with a second reflecting member before being cured and curing the second reflecting member before being cured. As a method for filling the notch 70 with the uncured second reflective member, known methods such as transfer molding, injection molding, compression molding, potting, etc. can be used. In order to adjust the thickness of the second reflective member 40 to a desired thickness, a part of the second reflective member 40 may be removed using a known method such as grinding. When the light emitting device includes a light-transmitting member, the second reflecting member may be formed to cover the upper surface and/or side surface of the light-transmitting member. When the second reflective member is formed to cover the entire upper surface of the translucent member, a portion of the second reflective member is removed so that at least a portion of the translucent member is exposed from the second reflective member. . Further, when a part of the second reflective member is removed in order to adjust the thickness of the second reflective member 40 to a desired thickness, a part of the light-transmitting member may also be removed. When removing a portion of the second reflective member and a portion of the translucent member, the upper surface of the second reflective member and the upper surface of the translucent member may be flush with each other.

[Individualization process]
When the intermediate body 100 is in the state of a collective substrate, as shown in FIG. 18, the second reflective member 40 and a part of the substrate 10 are removed along the broken line _S3 and the broken line _S4 , and each light emitting device is removed. Individualize. For example, each light emitting device can be separated into pieces by cutting the second reflective member 40 and the substrate 10 using a blade dicing method, a laser dicing method, or the like.

As described above, the light emitting device 1000 is manufactured by performing each of the above steps.

The light emitting device according to an embodiment of the present invention is a backlight device for a liquid crystal display, various lighting equipment, large displays, various display devices such as advertisements and destination guides, projector devices, digital video cameras, facsimiles, and copy machines. It can be used in image reading devices such as , scanners, etc.

1000A, 1000B, 1000C, 2000 Light emitting device 10 Substrate 11 Base material
118 recess 12 first wiring 13 second wiring 14 third wiring 15 via
151 4th wiring
152 Filling member 16 Hollow 18 Insulating film 20A First light emitting element 20B Second light emitting element 20C Third light emitting element 30 Reflective particle containing member 31 First reflecting member 32 First covering member 33 Second covering member 34 Adhesive layer 40 Second reflection Member 50 Transparent member 60 Conductive adhesive member 70 Notch 80 Rotating shaft

Claims (11)

a substrate having a base material having an upper surface and a first wiring arranged on the upper surface;
a first light extraction surface, a first electrode formation surface opposite to the first light extraction surface, a first side surface between the first light extraction surface and the first electrode formation surface; a first light emitting element having a pair of first electrodes on one electrode formation surface, and placed on the first wiring with the first electrode formation surface and the first wiring facing each other;
a conductive adhesive member that adheres and electrically connects the pair of first electrodes and the first wiring;
a first reflective member that exposes the first light extraction surface, covers the upper surface of the base material, and contains reflective particles;
a first covering member that exposes the first light extraction surface, covers at least a portion of the first reflective member and the first side surface, and has a lower concentration of the reflective particles than the first reflective member;
a second covering member that covers at least a portion of the first side surface;
a second reflective member that surrounds the second covering member and is in contact with the second covering member and the first reflective member in a top view;
The second reflecting member is a light-emitting device having, in a cross-sectional view, a narrow portion in contact with the first reflecting member, and a wide portion disposed above the narrow portion. a substrate having a base material having an upper surface and a first wiring arranged on the upper surface;
a first light extraction surface, a first electrode formation surface opposite to the first light extraction surface, a first side surface between the first light extraction surface and the first electrode formation surface; a first light emitting element having a pair of first electrodes on one electrode formation surface, and placed on the first wiring with the first electrode formation surface and the first wiring facing each other;
a first reflective member that exposes the first light extraction surface, covers the upper surface of the base material, and contains reflective particles;
a first covering member that exposes the first light extraction surface, covers at least a portion of the first reflective member and the first side surface, and has a lower concentration of the reflective particles than the first reflective member;
a second covering member that covers at least a portion of the first side surface;
a second reflective member that surrounds the second covering member and is in contact with the second covering member and the first reflective member in a top view;
The second reflecting member has a narrow portion in contact with the first reflecting member and a wide portion disposed above the narrow portion in a cross-sectional view,
The first light emitting element includes a first semiconductor layer, and a side surface of the first semiconductor layer is covered with the first reflective member. a substrate having a base material having an upper surface and a first wiring arranged on the upper surface;
a first light extraction surface, a first electrode formation surface opposite to the first light extraction surface, a first side surface between the first light extraction surface and the first electrode formation surface; a first light emitting element having a pair of first electrodes on one electrode formation surface, and placed on the first wiring with the first electrode formation surface and the first wiring facing each other;
a first reflective member that exposes the first light extraction surface, covers the upper surface of the base material, and contains reflective particles;
a first covering member that exposes the first light extraction surface, covers at least a portion of the first reflective member and the first side surface, and has a lower concentration of the reflective particles than the first reflective member;
a second covering member that covers at least a portion of the first side surface;
a second reflective member that surrounds the second covering member and is in contact with the second covering member and the first reflective member in a top view;
The second reflecting member has a narrow portion in contact with the first reflecting member and a wide portion disposed above the narrow portion in a cross-sectional view,
A light emitting device, wherein the first covering member is in contact with the second reflecting member. The light emitting device according to claim 3, wherein the thickness of the first covering member in a portion in contact with the first light emitting element is thicker than the thickness of the first covering member in a portion in contact with the second reflective member. The light emitting device according to any one of claims 1 to 4, comprising a second light emitting element having a different emission peak wavelength from the first light emitting element. The light emitting device according to any one of claims 1 to 5, wherein the upper surface of the base material has a recess surrounding the outer periphery, and a portion of the second reflective member is disposed within the recess. The light emitting device according to any one of claims 1 to 6, wherein an outer edge of the base material and an outer surface of the second reflective member are flush with each other. The light emitting device according to any one of claims 1 to 7, further comprising a translucent member that covers the first light extraction surface. preparing a substrate including a base material having an upper surface and a first wiring disposed on the upper surface;
a first light extraction surface, a first electrode formation surface opposite to the first light extraction surface, a first side surface between the first light extraction surface and the first electrode formation surface; a step of preparing a first light emitting element having a pair of first electrodes on one electrode formation surface;
placing a first light emitting element on the first wiring with the first electrode forming surface and the first wiring facing each other;
arranging a reflective particle-containing member on the upper surface of the base material so that at least a part of the upper surface of the base material that overlaps with the first light emitting element is exposed when viewed from above;
Spreading the reflective particle-containing member on the upper surface of the base material overlapping with the first light emitting element by centrifugal force;
including;
After the step of spreading the reflective particle-containing member by centrifugal force, forming a second covering member that covers the reflective particle-containing member;
After the step of forming the second covering member, the light emitting device includes the step of forming a second reflective member that surrounds the first light emitting element in a top view and is in contact with the second covering member and the reflective particle-containing member. Production method. The method for manufacturing a light-emitting device according to claim 9, wherein in the step of spreading the reflective particle-containing member by centrifugal force, the entire upper surface of the base material that overlaps with the first light-emitting element is covered with the reflective particle-containing member. The method for manufacturing a light emitting device according to claim 9 or 10, comprising the step of removing a part of the second reflective member and the substrate to separate them into pieces.

Images