JP2012253064A - Light-emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-emitting device whose mountability can be improved.SOLUTION: In a light-emitting device 1, a molded body 11 comprises: a rectangular annular part 113 which is disposed on the side of a light-emitting surface 10A of a lead 12; and a first column part 111 and a second column part 112 which are disposed on the side of a back surface 10B of the lead 12 and form part of a lower surface 10C.

Description

  The present invention relates to a side view type light emitting device.

  Conventionally, a light emitting device including a light emitting element (for example, a light emitting diode or a laser diode) has been widely used as a light source for a backlight for a liquid crystal television, a lighting fixture, or an optical communication device.

  Such a light-emitting device is generally classified into a top-view type and a side-view type according to the direction in which the light emitted from the light-emitting element is extracted. In the top view type light emitting device, light emitted from the light emitting element is extracted in a direction perpendicular to the mounting surface. In the side-view type light emitting device, light emitted from the light emitting element is extracted in a direction parallel to the mounting surface.

  Here, a package structure in which a first main surface and side surfaces of a plate-like lead are surrounded by a molded body and a second main surface of the plate-like lead is exposed from the molded body is known for the top view type light emitting device. (See Patent Document 1).

JP 2010-182770 A

  However, when the package structure described in Patent Document 1 is applied to a side-view type light-emitting device, the mountability of the light-emitting device may be reduced. Specifically, if the main surface of the plate-like lead is arranged perpendicularly to the mounting surface to be a side view type, the plate-like lead is arranged on the back side of the light emitting device, so light emission There is a problem that the device easily falls to the back side in the mounted state. Such a problem is particularly noticeable when a solder fillet is provided on the back surface of the light emitting device in order to mount the light emitting device.

  The present invention has been made in view of the above-described situation, and an object thereof is to provide a light emitting device capable of improving mountability.

  The light emitting device according to the present invention includes a molded body and a plate-like lead embedded in the molded body, and includes a light emitting surface, a back surface provided opposite to the light emitting surface, a light emitting surface, and a back surface. , A package having a mounting recess formed on the light emitting surface, and a back recess formed on the back surface, and a light emitting element mounted on the mounting recess. The lead has a first terminal portion exposed from the molded body at the bottom surface and the back surface recess. The molded body has a front portion disposed on the light emitting surface side of the lead and a back portion disposed on the back surface side of the lead and forming a part of the lower surface.

  ADVANTAGE OF THE INVENTION According to this invention, the light-emitting device which can improve mountability can be provided.

1 is a top perspective view of a light emitting device 1 according to a first embodiment. The bottom perspective view of light-emitting device 1 concerning a 1st embodiment. FIG. 2 is a top perspective view of the light emitting device 1 according to the first embodiment. 1 is a bottom perspective view of a light emitting device 1 according to a first embodiment. The front view of the light-emitting device 1 which concerns on 1st Embodiment. The rear view of the light-emitting device 1 which concerns on 1st Embodiment. The bottom view of the light-emitting device 1 which concerns on 1st Embodiment. The side view of the light-emitting device 1 which concerns on 1st Embodiment. The cut surface in the AA of FIG. The cut surface in the BB line of FIG. The perspective view of the circuit board 3 which concerns on 1st Embodiment. The figure for demonstrating the manufacturing method of the light-emitting device 1 which concerns on 1st Embodiment. The bottom perspective view of light-emitting device 1a concerning a 2nd embodiment. The upper surface perspective view of the light-emitting device 1a which concerns on 2nd Embodiment. The rear view of the light-emitting device 1a which concerns on 2nd Embodiment.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and the ratio of each dimension may be different from the actual one. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  In the following embodiment, a side view type light emitting device will be described. A side view type light emitting device is a type of light emitting device in which light emitted from a light emitting element is extracted in a direction parallel to a mounting surface of a mounting substrate. Such a side-view type light-emitting device has a feature that it is easy to fall forward or backward compared to a so-called top-view type light-emitting device because the depth is generally small.

  In the following embodiments, the direction from which the light emitted from the light emitting element is extracted is referred to as “first direction”, and when the light emitting element is mounted on the mounting substrate, the direction perpendicular to the mounting surface is referred to as “second direction”. A direction perpendicular to the first direction and the second direction is referred to as a “third direction”.

[First Embodiment]
<Schematic configuration of light-emitting device 1>
A schematic configuration of the light emitting device 1 according to the first embodiment will be described with reference to the drawings. FIG. 1 is a top perspective view of the light emitting device 1. FIG. 2 is a bottom perspective view of the light emitting device 1.

  The light emitting device 1 includes a package 10, a light emitting element 20, and a sealing resin 30. The light emitting device 1 is formed in a substantially rectangular parallelepiped shape, and the depth in the first direction is about 1.2 mm, the height in the second direction is about 1.0 mm, and the width in the third direction is about 4.0 mm. However, it is not limited to this.

(1) Package 10
The package 10 includes a molded body 11 and leads 12. The molded body 11 is formed in a substantially rectangular parallelepiped shape and forms the outer shape of the package 10. The molded body 11 includes a first pillar portion 111 and a second pillar portion 112. The lead 12 is formed in a plate shape and is embedded in the molded body 11. The lead 12 includes a first lead part 121 and a second lead part 122. The configuration of the molded body 11 and the lead 12 will be described later.

  The package 10 includes a light emitting surface 10A, a back surface 10B, a lower surface 10C, an upper surface 10D, a first side surface 10E1 (not shown in FIGS. 1 and 2, see FIG. 8), a second side surface 10E2, and a mounting recess. 10M and a back recess 10N.

  The light exit surface 10A is a surface from which the emitted light of the light emitting element 20 is extracted. On the light exit surface 10A, a mounting recess 10M for mounting the light emitting element 20 is formed. The back surface 10B is provided opposite to the light emitting surface 10A. A back surface recess 10N is formed on the back surface 10B. The back surface 10B is separated from each other with the back surface recess 10N interposed therebetween. The mounting recess 10M is a recess formed in the light exit surface 10A. The back recess 10N is a recess formed in the back 10B. The back recess 10N has a bottom surface 10F provided opposite to the light exit surface 10A. The bottom surface 10F is located between the light emitting surface 10A and the back surface 10B in the first direction.

(2) Light emitting element 20
The light emitting element 20 is placed on the first lead portion 121 inside the placement recess 10M. The light emitting element 20 is connected to the first lead part 121 via the first wire 21 and is connected to the second lead part 122 via the second wire 22. The light emitted from the light emitting element 20 is emitted from the light emitting surface 10 </ b> A toward the outside of the package 10.

  As such a light-emitting element 20, a light-emitting diode having a light-emitting layer of a semiconductor such as GaAlN, ZnS, SnSe, SiC, GaP, GaAlAs, AlN, InN, AlInGaP, InGaN, GaN, or AlInGaN on a substrate is preferably used. .

(3) Sealing resin 30
The sealing resin 30 is filled in the mounting recess 10 </ b> M and seals the light emitting element 20. As the sealing resin 30, a translucent resin such as a polyolefin resin, a polycarbonate resin, a polystyrene resin, an epoxy resin, an acrylic resin, an acrylate resin, a methacrylic resin (such as PMMA), a urethane resin, a polyimide resin, or polynorbornene. At least one resin selected from resins, fluororesins, silicone resins, modified silicone resins, modified epoxy resins and the like can be used. Further, such a material may contain, for example, a phosphor, a pigment, a filler, a diffusing material, or the like described in WO2006 / 038502 or JP2006-229055.

<Configuration of molded body 11 and lead 12>
The configurations of the molded body 11 and the leads 12 (first lead portion 121 and second lead portion 122) will be described with reference to the drawings.

FIG. 3 is a top perspective view of the light emitting device 1 showing the configuration of the lead 12. FIG. 4 is a bottom perspective view of the light emitting device 1 showing the configuration of the lead 12. FIG. 5 is a front view of the light emitting device 1. FIG. 6 is a rear view of the light emitting device 1. FIG. 7 is a bottom view of the light emitting device 1. FIG. 8 is a side view of the light emitting device 1. FIG. 9 is a cut surface taken along line AA of FIG. FIG. 10 is a cut surface taken along line BB in FIG.
In FIGS. 3 and 4, the outer edge of the molded body 11 is indicated by a broken line.

(1) Configuration of First Lead Part 121 As shown in FIGS. 3 and 4, the first lead part 121 includes a first connection part 121a, a first terminal part 121b, and a heat sink part 121c. .

  The 1st connection part 121a is formed in plate shape. As shown in FIG. 5, the first connection portion 121a is exposed from the molded body 11 in the mounting recess 10M. Moreover, the 1st connection part 121a is exposed from the molded object 11 also in 10 C of lower surfaces, as shown in FIG. The first connection part 121 a supports the light emitting element 20 and is connected to the light emitting element 20 via the first wire 21.

  The 1st terminal part 121b is connected with the back side of the 1st connection part 121a. As shown in FIG. 6, the first terminal portion 121b is exposed from the molded body 11 at the bottom surface 10F of the back recess 10N. Moreover, the 1st terminal part 121b is exposed from the molded object 11 also in 10 C of lower surfaces, as shown in FIG. The first terminal portion 121b is formed in a substantially rectangular parallelepiped shape, and is arranged so that the long side is parallel to the second direction. The 1st terminal part 121b has the 1st terminal crevice L1 which continues and opens to bottom 10F and bottom 10C of back crevice 10N. As described later, when the light emitting device 1 is mounted, a solder fillet is formed in the first terminal recess L1.

  The heat sink part 121c is connected to the back side of the first connection part 121a. As shown in FIG. 6, the heat sink 121 c is exposed from the molded body 11 on the bottom surface 10 </ b> F of the back recess 10 </ b> N. However, since the heat sink part 121c is not directly connected to the first terminal part 121b, the heat sink part 121c is separated from the first terminal part 121b on the bottom surface 10F of the rear recess 10N. Since the molded body 11 is disposed in the spaced-apart portion, the contact area between the first lead portion 121 and the molded body 11 can be increased, and the adhesion between them can be improved. Further, as shown in FIG. 7, the heat sink portion 121c is exposed from the molded body 11 also on the lower surface 10C. The heat sink part 121c is formed in a substantially rectangular parallelepiped shape. The heat sink portion 121c has a heat sink recess L2 that is open to the bottom surface 10F and the lower surface 10C of the back recess 10N. As will be described later, when the light emitting device 1 is mounted, a solder fillet is formed in the heat sink recess L2.

(2) Configuration of Second Lead Portion 122 As shown in FIGS. 3 and 4, the second lead portion 122 includes a second connection portion 122a and a second terminal portion 122b.

  The second connection part 122a is formed in a plate shape. As shown in FIG. 5, the second connection portion 122 a is exposed from the molded body 11 in the mounting recess 10 </ b> M. Moreover, the 2nd connection part 122a is exposed from the molded object 11 also in 10 C of lower surfaces, as shown in FIG. The second connection part 122 a is connected to the light emitting element 20 through the second wire 22.

  The 2nd terminal part 122b is connected with the back side of the 2nd connection part 122a. As shown in FIG. 6, the second terminal portion 122b is exposed from the molded body 11 on the bottom surface 10F of the back recess 10N. Further, as shown in FIG. 7, the second terminal portion 122b is exposed from the molded body 11 also on the lower surface 10C. The second terminal portion 122b is formed in a substantially rectangular parallelepiped shape, and is arranged so that the long side is parallel to the second direction. The second terminal portion 122b has a second terminal recess L3 that is open to the bottom surface 10F and the bottom surface 10C of the back recess 10N. As will be described later, when the light emitting device 1 is mounted, a solder fillet is formed in the second terminal recess L3.

(3) Material of Lead 12 The lead 12 (the first lead portion 121 and the second lead portion 122) is made of a material having a relatively large thermal conductivity (for example, about 200 W / (m · K) or more). It is preferable. Thereby, the heat generated from the light emitting element 20 can be efficiently transmitted. As such a material, for example, a single layer or a plurality of metals such as Ni, Au, Cu, Ag, Mo, W, aluminum, gold, iron, or an alloy such as iron-nickel alloy, phosphor bronze, iron-containing copper, etc. Layers can be used.
The surface of the lead 12 may be covered with a metal film containing Ag or Au.

(4) Configuration of Molded Body 11 The molded body 11 includes a first column part 111, a second column part 112, a rectangular annular part 113, and an intermediate part 114, as shown in FIGS. Is done. The first pillar part 111, the second pillar part 112, the rectangular annular part 113, and the intermediate part 114 are integrally formed.

  Each of the first column portion 111 and the second column portion 112 is formed in a column shape along the second direction. Each of the first pillar portion 111 and the second pillar portion 112 forms part of the lower surface 10C and the upper surface 10D. In addition, each of the first pillar portion 111 and the second pillar portion 112 is disposed at both ends in the third direction of the light emitting device 1. The first pillar portion 111 forms a part of the first side surface 10E1, and the second pillar portion 112 forms a part of the second side surface 10E2. As shown in FIG. 9, the first pillar portion 111 and the second pillar portion 112 are disposed on the back side of the lead 12 and are connected to the intermediate portion 114. In the third direction, a back recess 10N is provided between the first pillar portion 111 and the second pillar portion 112.

  Here, as shown in FIG. 9, the first column portion 111 is adjacent to the first terminal portion 121 b in the third direction. The first terminal portion 121b is disposed closer to the first column portion 111 than the center of the light emitting device 1 in the third direction. Similarly, the second pillar portion 112 is adjacent to the second terminal portion 122b in the third direction. The second terminal portion 122b is disposed closer to the second column portion 112 than the center of the light emitting device 1 in the third direction.

  As shown in FIGS. 7 to 10, the rectangular annular portion 113 is formed in a rectangular annular shape so as to surround the mounting recess 10 </ b> M. The rectangular annular portion 113 is arranged on the light emitting surface side of the lead 12 and is continuous with the intermediate portion 114. The rectangular annular portion 113 forms the light emission surface 10A.

  As shown in FIGS. 7 to 10, the intermediate portion 114 surrounds the side of the lead 12. The intermediate part 114 is connected to the first pillar part 111, the second pillar part 112, and the rectangular annular part 113.

(5) Material of Molded Body 11 The molded body 11 is made of a material having heat resistance, moderate strength, and insulating properties that do not easily transmit light emitted from the light emitting element 20 or external light. As such a material, for example, a triazine derivative epoxy resin which is a thermosetting resin is suitable. This thermosetting resin may contain an acid anhydride, an antioxidant, a release material, a light reflecting member, an inorganic filler, a curing catalyst, a light stabilizer, and a lubricant.

  Further, as the light reflecting member, titanium dioxide filled in 0.1 to 90 wt%, preferably 10 to 60 wt% may be used. However, the material of the molded body 11 is not limited to this. For example, among thermosetting resins, at least selected from epoxy resins, modified epoxy resins, silicone resins, modified silicone resins, acrylate resins, and urethane resins. One kind of resin can be used. In particular, an epoxy resin, a modified epoxy resin, a silicone resin, and a modified silicone resin are suitable as the material of the molded body 11. Further, a thermoplastic resin such as a liquid crystal polymer, a polyphthalamide resin, or polybutylene terephthalate (PBT) may be used.

(Configuration of circuit board)
Next, the configuration of the circuit board according to the present embodiment will be described with reference to the drawings. FIG. 11 is a perspective view of the circuit board 3 according to the present embodiment.

As shown in FIG. 11, the circuit board 3 includes the light-emitting device 1, the mounting board 2, the first solder fillet 4, the second solder fillet 5, and the third solder fillet 6.
The mounting substrate 2 has a first land R1 and a second land R2 formed on the mounting surface 2A. The light emitting device 1 is disposed on the mounting surface 2A. The first land R1 is a metal member for connecting the first terminal portion 121b and the heat sink portion 121c. The second land R2 is a metal member for connecting the second terminal portion 122b. The first and second lands R1, R2 are made of, for example, copper foil.

  The first solder fillet 4 is disposed in the first terminal recess L1 and mechanically, electrically and thermally connects the first terminal portion 121b and the first land R1. The second solder fillet 5 is disposed in the heat sink recess L2, and mechanically, electrically and thermally connects the heat sink recess L2 and the first land R1. The third solder fillet 6 is disposed in the second terminal recess L3 and mechanically, electrically and thermally connects the second terminal portion 122b and the second land R2.

<Method for Manufacturing Light-Emitting Device 1>
Next, a method for manufacturing the light emitting device 1 according to the first embodiment will be described with reference to the drawings. FIG. 12 is a diagram for explaining a method for manufacturing the light emitting device 1.

  First, a copper plate (Ag plated) having a predetermined thickness (for example, about 0.5 mm) is punched into a desired shape. Thereby, as shown in FIG. 12, the metal plate 2 comprised by the several S-shaped plate-shaped member 200 continued in a predetermined direction is formed.

  Next, the outer edge of the S-shaped plate member 200 and the center three places are pressed. Accordingly, as shown in FIG. 12, the base portion 210 having a thickness smaller than the above-mentioned predetermined thickness, the first to third rectangular annular portions 211 to 213 having a predetermined thickness, and each having a thickness smaller than the predetermined thickness. First to third recesses 221 to 223 formed at the center of the rectangular annular portion are formed.

  Next, the metal plate 2 is molded with a resin material (material of the molded body 11) by a transfer molding method. As a result, a package array 220 (see the broken line shown in FIG. 12) in which the metal plate 2 is embedded in the resin material is formed. In the package array 220, the first to third rectangular annular portions 211 to 213 are exposed on the first main surface of the package array 220, and the base portion 210 is exposed on the second main surface of the package array 220. Yes.

  Next, as shown in FIG. 12, the package array 220 is cut along cutting lines P1 and P2 with a dicing saw. As a result, the plurality of light emitting devices 1 are cut out from the package array 220.

After that, by applying Ag plating to the cut surface by the dicing saw, the gap between the lead and the molded body is filled with Ag, and the exposed copper is covered with Ag.
<Action and effect>
The molded body 11 is disposed on the rectangular annular portion 113 (an example of “front portion”) disposed on the light exit surface 10A side of the lead 12 and on the back surface 10B side of the lead 12, and forms a part of the lower surface 10C. It has the 1 pillar part 111 and the 2nd pillar part 112 (an example of a "back part").

  Therefore, since the plate-like lead 12 placed vertically can be supported from the front and rear by the rectangular annular portion 113, the first pillar portion 111, and the second pillar portion 112, the mountability of the light emitting device 1 can be improved. it can.

[Second Embodiment]
<Configuration of Light Emitting Device 1a>
A schematic configuration of the light emitting device 1a according to the second embodiment will be described with reference to the drawings. In the following description, differences from the above-described light emitting device 1 will be mainly described. FIG. 13 is a bottom perspective view of the light emitting device 1a. FIG. 14 is a top perspective view of the light emitting device 1a. FIG. 15 is a rear view of the light emitting device 1a.

  As shown in FIGS. 13 to 15, in the light emitting device 1 a, the first lead part 121 includes a first connection part 121 a, a first terminal part 121 b, and a heat sink part 121 d.

The first terminal portion 121b is formed in a substantially rectangular parallelepiped shape. The 1st terminal part 121b has the 1st terminal crevice L1 which continues and opens to bottom 10F and bottom 10C of back crevice 10N.
The heat sink part 121d is connected to the first connection part 121a above the first terminal part 121b. The first heat sink portion 121d is exposed from the molded body 11 at the bottom surface 10F of the back recess 10N, and is not exposed from the molded body 11 at the lower surface 10C. Therefore, no heat sink recess is formed in the first heat sink portion 121d.

  As shown in FIGS. 13 to 15, in the light emitting device 1a, the second lead portion 122 includes a first connection portion 122a, a second terminal portion 122b, and a second heat sink portion 122c.

The second terminal portion 122b is formed in a substantially rectangular parallelepiped shape. The second terminal portion 122b has a second terminal recess L3 that is open to the bottom surface 10F and the bottom surface 10C of the back recess 10N.
The second heat sink part 122c is coupled to the second connection part 122a above the second terminal part 122b. The second heat sink portion 122c is exposed from the molded body 11 at the bottom surface 10F of the back recess 10N, and is not exposed from the molded body 11 at the lower surface 10C.

[Other Embodiments]
Although the present invention has been described according to the above-described embodiments, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

(A) In the above-described embodiment, the rectangular parallelepiped first pillar portion 111 and the second pillar portion 112 have been described as an example of the “back portion”, but the present invention is not limited to this. The first pillar portion 111 and the second pillar portion 112 may be formed in a step shape in a top view, a side view, or a back view, or may be formed in a trapezoidal shape in a top view, a side view, or a back view. Good. Further, the first pillar portion 111 and the second pillar portion 112 may be formed in a tapered shape upward in a side view or a rear view. Thus, the mountability of the light emitting device 1 can be improved by appropriately designing the shapes of the first pillar portion 111 and the second pillar portion 112.

  Further, as the “back portion”, only one column portion may be formed. In this case, the position of the column portion in the third direction can be set as appropriate. For example, if the column portion is arranged in the center of the light emitting device 1 in the third direction, the mountability of the light emitting device 1 can be easily improved.

  Further, the “back” is not limited to a columnar shape. For example, the “back” may be a cubic shape or a semi-spherical shape. The outer shape of the “back” can be arbitrarily designed in consideration of the mountability of the light emitting device 1.

(B) Although the rectangular annular portion 113 has been described as an example of the “front portion” in the above embodiment, the present invention is not limited to this. The outer shape of the “front part” may be a U-shape.

(C) In the above embodiment, the first lead part 121 has the heat sink part (the heat sink part 121c or the first heat sink part 121d) separated from the first terminal part 121b. However, the present invention is not limited to this. . The first lead part 121 may not have a heat sink part. Moreover, the heat sink part may be connected with the 1st terminal part 121b. In this case, the heat dissipation effect of the light emitting device 1 can be further improved.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Light-emitting device 2 ... Mounting board 3 ... Circuit board 4 ... 1st solder fillet 5 ... 2nd solder fillet 6 ... 3rd solder fillet 10 ... Package 11 ... Molding body 111 ... 1st pillar part 112 ... 2nd pillar part 113 ... Rectangular annular part 114 ... Intermediate part 12 ... Lead 121 ... First lead part 121a ... First connection part 121b ... First terminal part 121c ... Heat sink part 122 ... Second lead part 122a ... Second connection part 122b ... Second terminal Part 20 ... Light emitting element 30 ... Sealing resin 2 ... Metal plate 200 ... S-shaped plate member 210 ... Base parts 211 to 213 ... First to third rectangular annular parts 221 to 223 ... First to third recesses 220 ... Package array

Claims (8)

A molded body, and a plate-like lead embedded in the molded body, a light emitting surface, a back surface provided opposite to the light emitting surface, and the light emitting surface and a lower surface continuous to the back surface. A package having a mounting recess formed on the light exit surface and a back recess formed on the back surface;
A light emitting device placed in the placement recess,
With
The lead has a first terminal portion exposed from the molded body in the lower surface and the back surface recess,
The molded body has a front portion disposed on the light emission surface side of the lead and a back portion disposed on the back surface side of the lead and forming a part of the lower surface.
Light emitting device. The back part is constituted by a first pillar part and a second pillar part formed perpendicular to the lower surface,
The back recess is formed between the first pillar part and the second pillar part,
The light emitting device according to claim 1. The first terminal portion is adjacent to the first pillar portion,
The light emitting device according to claim 2. The lead has a second terminal portion exposed from the molded body at the lower surface and the rear recess.
The second terminal portion is adjacent to the second pillar portion.
The light emitting device according to claim 3. The package has a first side surface and a second side surface continuous to the light emitting surface, the back surface, and the lower surface,
The first pillar portion forms a part of the first side surface,
The second pillar portion forms part of the second side surface.
The light emitting device according to claim 2. The first lead is
A connecting portion connected to the first terminal portion and exposed from the molded body in the mounting recess;
A heat sink that is coupled to the connecting portion and exposed from the molded body in the back recess;
Having
The light emitting device according to claim 1. The first terminal portion is formed in a rectangular parallelepiped shape, and is arranged such that a long side is parallel to a direction perpendicular to the lower surface.
The light emitting device according to claim 1. The first terminal portion is covered with a metal film containing Ag or Au.
The light emitting device according to claim 1.

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