JP7177327B2 - light emitting device - Google Patents

Description

The present invention relates to light emitting devices.

Patent Document 1 discloses a light-emitting device in which a wiring board having through-holes for passing light emitted from a light-emitting element mounted on a support and reflected light and a metal plate on which a light-emitting element is mounted are attached under the wiring board. disclosed.

Japanese Patent Application Laid-Open No. 2007-109701

However, in the light emitting device described above, the light emitted from the light emitting element may be absorbed by the wall surface of the through hole of the wiring board, resulting in a decrease in the light extraction efficiency of the light emitting device.
An object of the present invention is to provide a light emitting device with improved light extraction efficiency.

A light emitting device according to an aspect of the present invention includes a first surface, a convex portion outside the first surface and having a height higher than the first surface, and a convex portion outside the convex portion and the a conductive support member having a second surface lower in height than the projection; a light emitting element mounted on the first surface; and a first insulating material mounted on the second surface. a member, a wiring placed on the first insulating member, and a resin frame that surrounds the first surface in a plan view and covers at least part of the first insulating member, The convex portion is positioned on a straight line connecting the element and the first insulating member.

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

1A is a schematic plan view of a light emitting device according to an embodiment; FIG. FIG. 1B is a schematic cross-sectional view along line 1B-1B of FIG. 1C is a schematic cross-sectional view of a light-emitting device according to Modification 1. FIG. 1C is a schematic cross-sectional view of a light-emitting device according to Modification 2. FIG. 1E is a schematic cross-sectional view of a light-emitting device according to Modification 3. FIG. FIG. 2 is a schematic plan view of a support member. FIG. 3 is a schematic plan view of the light emitting device according to the embodiment with the resin frame, the covering member, and the second insulating member omitted.

Embodiments for implementing the present disclosure will be described below with reference to the drawings. However, the embodiments shown below are examples of light-emitting devices for embodying the technical idea of the present disclosure, and the present disclosure does not limit the light-emitting device to the following.

Moreover, this specification does not in any way specify the members shown in the claims as the members of the embodiment. In particular, the dimensions, materials, shapes, relative positions, and the like of components described in the embodiments are not intended to limit the scope of the present disclosure only to them unless specifically described. Note that the sizes and positional relationships of members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same names and symbols indicate the same or homogeneous members, and detailed description thereof will be omitted as appropriate.

<Embodiment>
A light emitting device 1000 according to an embodiment of the present invention will be described with reference to FIGS. 1A to 3. FIG. The light-emitting device 1000 includes a conductive support member 10 , a light-emitting element 20 , a first insulating member 30 , wiring 40 and a resin frame 60 . The support member 10 has a first surface 101 , a convex portion 11 outside the first surface 101 and higher than the first surface 101 , and a convex portion 11 outside the convex portion 11 and higher than the convex portion 11 . and a low second surface 102 . The light emitting element 20 is placed on the first surface 101 of the support member 10 . The first insulating member 30 rests on the second surface 102 of the support member 10 . The wiring 40 is placed on the first insulating member 30 . The resin frame 60 surrounds the first surface 101 in plan view and covers at least a portion of the first insulating member 30 . The convex portion 11 is positioned on a straight line connecting the light emitting element 20 and the first insulating member 30 .

Since the resin frame 60 covers at least a part of the first insulating member 30 , the light emitted from the light emitting element 20 is blocked by the first insulating member 30 and does not directly hit the first insulating member 30 . As a result, part of the light emitted from the light emitting element 20 can be prevented from being absorbed by the first insulating member 30, so that the light extraction efficiency of the light emitting device can be improved.

The reflectance of the resin frame 60 is higher than the reflectance of the first insulating member 30 at the peak wavelength of the light emitted by the light emitting element 20 . By doing so, the light emitted from the light emitting element 20 is less likely to be absorbed by the resin frame 60, and the light extraction efficiency of the light emitting device can be improved.

Since the convex portion 11 is positioned on a straight line connecting the light emitting element 20 and the first insulating member 30 , part of the light emitted from the light emitting element 20 is blocked by the convex portion 11 to provide the first insulating property. It does not come into direct contact with the member 30 . As a result, part of the light emitted from the light emitting element 20 can be prevented from being absorbed by the first insulating member 30, so that the light extraction efficiency of the light emitting device can be improved.

The reflectance of the convex portion 11 is higher than the reflectance of the first insulating member 30 at the peak wavelength of the light emitted from the light emitting element 20 . By doing so, the light emitted from the light emitting element 20 is less likely to be absorbed by the convex portion 11, and the light extraction efficiency of the light emitting device can be improved.

As shown in FIG. 1B, it is preferable that the first insulating member is positioned outside the range where the light emitted from the light emitting element directly reaches. In other words, it is preferable that the first insulating member is not located in a range where the light emitted from the light emitting element directly reaches. By doing so, it is possible to prevent the light emitted from the light emitting element from being absorbed by the first insulating member.

Specifically, the range to which the light emitted from the light emitting element directly reaches can be defined by a straight line connecting the surface of the light emitting element and the surrounding light shielding member. Examples of the light shielding member include the supporting member 10, the first insulating member 30, the wiring 40, and the resin frame 60. Moreover, the wire 50 and the second insulating member 80, which will be described later, can also be used as the light shielding member. Note that the covering member 70, which will be described later, is translucent and is not a light shielding member.

As shown in FIG. 1B, the height of the convex portion 11 is preferably higher than the height of the light emitting element 20 . By doing so, the light emitted from the light emitting element can be easily blocked by the convex portion 11, so that the light extraction efficiency of the light emitting device is improved.

The height of the protrusion 11 is preferably higher than the height of the first insulating member 30 . By doing so, it is possible to prevent the light emitted from the light emitting element from being absorbed by the first insulating member, thereby improving the light extraction efficiency of the light emitting device.

As shown in FIG. 2, the convex portion 11 preferably surrounds the first surface 101 . By doing so, as shown in FIG. 1A, the light emitting element is surrounded by the projections in plan view, so that the light emitted from the light emitting element is likely to be blocked by the projections. Thereby, it is possible to suppress absorption of the light emitted from the light emitting element by the first insulating member.

As shown in FIG. 1B, it is preferable that the convex portion 11 is formed by bending the support member 10 . In other words, in a cross-sectional view, the fifth surface 105 located on the side opposite to the upper surface of the convex portion 11 is located on the side opposite to the third surface 103 located on the side opposite to the first surface 101 and the second surface 102 . higher than the fourth surface 104 that By doing so, the projections can be formed by a known method such as press working from the flat support member, which facilitates the formation of the projections. Moreover, when bending a flat support member, the first surface 101 and the second surface 102 are positioned substantially on the same plane. In this specification, the term “substantially the same plane” means that the height difference of each surface is allowed to fluctuate by about 15 μm.

The side surface 110 of the protrusion 11 may be vertical, but preferably has a shape that tapers toward the upper surface of the protrusion. By doing so, the light emitted from the light emitting element is more likely to travel upward when reflected by the side surface 110 of the convex portion 11, so that the light extraction efficiency of the light emitting device is improved.

In a cross-sectional view, the third surface 103 located on the opposite side of the first surface 101 and the fourth surface 104 located on the opposite side of the second surface 102 are preferably located on substantially the same plane. By doing so, when the light emitting device 1000 is mounted on the substrate, heat can be easily released from the third surface 103 and the fourth surface 104 to the substrate.

As shown in FIG. 1C, in a cross-sectional view, the third surface 103 located on the opposite side of the first surface 101, the fourth surface 104 located on the opposite side of the second surface 102, and the upper surface of the convex portion 11 are opposite to each other. and the fifth surface 105 positioned on the side are preferably positioned substantially on the same plane. By doing so, when the light emitting device is mounted on the substrate, heat can be easily released from the third surface 103, the fourth surface 104, and the fifth surface 105 to the substrate.

The number of light emitting elements 20 may be one or plural. If the light-emitting device has a plurality of light-emitting elements 20, it is preferable to connect them in series so that the same current is applied to each light-emitting element 20. FIG. Further, as shown in FIG. 3, an element group in which the same number of light emitting elements 20 are connected in series may be connected in parallel to the wiring 40 . By doing so, it is possible to suppress variation in the current supplied to each light emitting element.

As shown in FIG. 1A, the light emitting device 1000 may include a wire 50 and a covering member 70. As shown in FIG. A wire 50 electrically connects the light emitting element 20 and the wiring 40 . The covering member 70 covers the light emitting element 20 . By including the resin frame 60 in the light emitting device 1000, the resin frame 60 can function as a dam that blocks the covering member 70 when the covering member 70 is formed by potting, for example. That is, the resin frame 60 is formed so as to contact and surround the covering member 70 . The upper surface of the covering member 70 may be flat, convex, or concave.

As shown in FIG. 1D , the resin frame 60 may cover at least a portion of each member of the first insulating member 30 , the wiring 40 , the second surface 102 , and the convex portion 11 . By doing so, the light emitted from the light emitting element is blocked by the resin frame, so that the absorption of the light emitted from the light emitting element 20 by the first insulating member 30 and the wiring 40 can be suppressed. Moreover, it is preferable that the convex portion 11 is positioned inside the resin frame 60 . That is, it is preferable that the convex portion 11 is positioned on a straight line connecting the light emitting element 20 and the resin frame 60 . By doing so, part of the light from the light emitting element 20 that is irradiated onto the resin frame 60 can be blocked. Accordingly, deterioration of the resin frame 60 due to the light emitted from the light emitting element 20 can be suppressed.

The covering member 70 may contain a wavelength converting member 71, as shown in FIG. 1E. The wavelength conversion member 71 is a member that wavelength-converts the light of the first peak wavelength emitted by the light emitting element 20 into the light of the second peak wavelength different from the first peak wavelength. By including the wavelength conversion member 71 in the covering member 70, mixed-color light in which light of the first peak wavelength emitted by the light emitting element 20 and light of the second peak wavelength emitted by the wavelength conversion member 71 are mixed is output. can be done. For example, if a blue LED is used as the light emitting element 20 and a phosphor such as YAG is used as the wavelength conversion member 71, the blue light from the blue LED and the yellow light emitted by the phosphor excited by the blue light are mixed to obtain It is possible to construct a light-emitting device that outputs white light that is

The wavelength converting members 71 may be uniformly dispersed in the covering member 70 , or the wavelength converting members 71 may be unevenly distributed near the light emitting element 20 rather than the upper surface of the covering member 70 . By doing so, even if the wavelength conversion member 71 is weak against moisture, the coating member 70 also functions as a protective layer, so deterioration of the wavelength conversion member 71 can be suppressed. Examples of the wavelength conversion material that are vulnerable to moisture include fluoride-based phosphors such as KSF-based phosphors, sulfide-based phosphors, chloride-based phosphors, silicate-based phosphors, and phosphate-based phosphors. .

As shown in FIG. 1E, the covering member 70 may contain a light diffusing material 72 . The light diffusing material 72 reflects and/or refracts the light from the light emitting element 20 due to the difference in refractive index from the covering member 70 to diffuse the light. Thereby, luminance unevenness in the covering member 70 can be suppressed. Further, when the coating member 70 contains the wavelength converting member 71 and the light diffusing material 72, color unevenness can be suppressed.

The light emitting device 1000 may have a second insulating member 80 . A second insulating member 80 is placed on the wiring 40 . By providing the second insulating member 80, the wiring 40 can be protected. As with the first insulating member 30, the second insulating member 80 may absorb the light emitted from the light emitting element by the first insulating member. Therefore, it is preferable that the convex portion 11 is positioned on a straight line connecting the light emitting element 20 and the second insulating member 80 . By doing so, it is possible to prevent the second insulating member 80 from absorbing the light emitted from the light emitting element 20 .

The reflectance of the convex portion 11 is higher than the reflectance of the second insulating member 80 at the peak wavelength of the light emitted by the light emitting element. By doing so, the light emitted from the light emitting element is less likely to be absorbed by the convex portion, and the light extraction efficiency of the light emitting device can be improved.

It is preferable that the second insulating member is positioned outside the range where the light emitted from the light emitting element directly reaches. In other words, it is preferable that the second insulating member is not positioned within a range where the light emitted from the light emitting element directly reaches. By doing so, it is possible to prevent the light emitted from the light emitting element from being absorbed by the second insulating member.

The height of the protrusion 11 is preferably higher than the height of the second insulating member 80 . By doing so, it is possible to suppress the light emitted from the light emitting element from being absorbed by the second insulating member, thereby improving the light extraction efficiency of the light emitting device.

Preferably, the resin frame 60 covers at least part of the second insulating member 80 . The light emitted from the light emitting element 20 is blocked by the resin frame 60 and does not hit. This can prevent part of the light emitted from the light emitting element 20 from being absorbed by the second insulating member 80, thereby improving the light extraction efficiency of the light emitting device.

The reflectance of the resin frame 60 is higher than the reflectance of the second insulating member 80 at the peak wavelength of the light emitted by the light emitting element. By doing so, the light emitted from the light emitting element is less likely to be absorbed by the resin frame 60, and the light extraction efficiency of the light emitting device can be improved.

The light emitting device 1000 may have a protection element 90 as shown in FIG. One or a plurality of protection elements 90 may be provided. The protective element 90 may be any known element mounted on the light emitting device.

It is preferable that the protective element 90 is partially or wholly covered with a resin frame. Thereby, it is possible to prevent the light from the light emitting element 20 from being absorbed by the protective element 90 . In addition, the light extraction efficiency of the light emitting device is improved by forming the resin frame with a member having a higher reflectance with respect to the peak wavelength of the light emitting element 20 than the protection element 90 .

Materials and the like suitable for each component of the light emitting device of the embodiment will be described below.

(Support member 10)
The support member 10 is for arranging electronic components such as light emitting elements and protective elements. The support member 10 is preferably made of a material with high thermal conductivity. For example, by using a material having a thermal conductivity of about 200 W/(m·K) or more, the heat generated by the light emitting element 20 can be easily conducted to the support member 10 . Also, the support member 10 is preferably made of a material having a high reflectance. The high reflectance of the support member 10 improves the light extraction efficiency of the light emitting device. Examples of materials with high thermal conductivity and reflectance include metal materials such as aluminum alloys.

(Light emitting element 20)
The light emitting element 20 is a semiconductor element that emits light by itself when a voltage is applied, and a known semiconductor element made of a nitride semiconductor or the like can be applied. The emission wavelength of the light emitting element can be selected from the ultraviolet region to the infrared region, including the visible region (380 to 780 nm). For example, a nitride semiconductor can be used as a light emitting element with a peak wavelength of 430 to 490 nm. As the nitride semiconductor, In _X Al _Y Ga _1-XY N (0≦X, 0≦Y, X+Y≦1) or the like can be used. Alternatively, the light emitting element 20 may be arranged on the support member via a submount.

The shape of the light emitting element 20 may be an arbitrary shape such as a triangle, a square, a polygon such as a hexagon, or a shape similar to these when viewed from above. Also, the light emitting element 20 is a single-sided electrode in which an n-electrode and a p-electrode are formed on the same side.

The light emitting element 20 is face-up mounted on the first surface 101 of the support member. Face-up mounting is a form in which the surface of the light emitting element 20 opposite to the surface on which the electrodes are formed faces the supporting member 10 . A bonding member between the light emitting element 20 and the support member may be an insulating bonding member or a conductive bonding member, and a known bonding member may be used. For example, insulating bonding members include epoxy resins, silicone resins, modified resins thereof, and the like, and conductive bonding members include conductive pastes such as silver, gold, and palladium, and Au—Sn eutectic. Brazing materials such as solder and low-melting-point metals can be used.

(First insulating member 30)
The first insulating member is a member for preventing a short circuit between the supporting member and the wiring. A first insulating member rests on the second surface of the support member 10 . Examples of materials for the first insulating member include glass epoxy, resin, and ceramics.

(wiring 40)
The wiring is a member electrically connected to the light emitting element via a wire or the like. A wire is placed on the first insulating member. The wiring can be made of a metal such as copper, aluminum, gold, silver, tungsten, iron, nickel, or an alloy such as an iron-nickel alloy or phosphor bronze. The thickness of the wiring is, for example, 5 μm to 80 μm.

(wire 50)
The wire 50 is for electrically connecting the light emitting element 20 and the wiring 40 . Examples of materials for the wire 50 include those using metals including gold, silver, copper, platinum, aluminum, and the like. Note that the diameter of the wire 50 is not particularly limited, and can be appropriately selected according to the purpose and application. As the wire bonding method, known methods such as ball bonding and wedge bonding may be used.

(resin frame 60)
The resin frame 60 is annularly provided to surround the first surface of the support member. Since the resin frame 60 is provided so as to surround the light emitting element 20 , the uncured raw material to be the covering member can be held within the resin frame 60 . The resin frame 60 is formed by arranging an uncured raw material, which is the base of the resin frame 60, in a region where the resin frame 60 is desired to be formed, and curing the raw material.

Materials for the resin frame 60 include phenol resin, epoxy resin, BT resin, PPA, and silicone resin. In particular, as the material of the resin frame 60, a silicone resin having excellent light resistance is preferable. In addition, by dispersing powder such as a reflective member that does not easily absorb light from the light emitting element 20 and has a large difference in refractive index with respect to the base resin in the base resin, the light emitting element 20 can be efficiently emitted. of light can be reflected. As the reflecting member, for example, titanium oxide, aluminum oxide, zirconium oxide, and magnesium oxide can be used. In particular, titanium oxide is preferable because it is relatively stable against moisture and has a high refractive index. The resin frame 60 is a member having a reflectance of 60% or more, preferably 70% or more, with respect to the light from the light emitting element 20 . By doing so, the light reaching the resin frame 60 is less likely to be absorbed by the resin frame, and the light extraction efficiency of the light emitting device is improved.

(Coating member 70)
As a material of the covering member 70, a translucent resin material or the like can be used. The resin material of the covering member 70 includes polycarbonate resin, epoxy resin, phenol resin, silicone resin, acrylic resin, polymethylpentene resin, polynorbornene resin, modified resins thereof, hybrid resins containing one or more of these resins, and the like. can be used. In particular, as the material of the covering member 70, dimethyl-based silicone resin and phenyl-based silicone resin, which are excellent in light resistance, are preferable.

(Wavelength conversion member 71)
Phosphor particles that can be excited by light emitted from the light emitting element are used as the wavelength conversion member 71 . For example, phosphors that can be excited by a blue light emitting device or an ultraviolet light emitting device include a cerium-activated yttrium aluminum garnet phosphor (YAG:Ce), a cerium activated lutetium aluminum garnet phosphor. (LAG:Ce), nitrogen-containing calcium aluminosilicate phosphor activated with europium and/or chromium (CaO—Al ₂ O3—SiO ₂ :Eu, Cr), silicate phosphor activated with europium ((Sr , Ba) ₂ SiO ₄ :Eu), β-SiAlON phosphors, CASN phosphors, SCASN phosphors and other room compound phosphors; KSF phosphors and other fluoride phosphors, sulfide phosphors, Chloride-based phosphors, silicate-based phosphors, phosphate-based phosphors, quantum dot phosphors, and the like can be mentioned. By combining these phosphors with a blue light emitting element or an ultraviolet light emitting element, light emitting devices with various wavelengths can be manufactured.

(Light diffusion material 72)
Titanium oxide, zirconium oxide, aluminum oxide, silicon oxide, or the like can be used as the material of the light diffusing material 72 . In particular, titanium oxide is preferable because it is relatively stable against moisture and has a high refractive index.

(Second insulating member 80)
The second insulating member is a member for protecting the wiring. In addition, by placing the second insulating member on the wiring, it is possible to suppress short-circuiting of the light-emitting device due to contact between the wiring and the conductive member. As the material of the second insulating member, the same material as that of the first insulating member can be used.

(protective element 90)
For example, the protection element 90 blocks a current flowing in the reverse direction when a reverse voltage is applied to the light emitting element, or prevents the light emitting element from flowing when a forward voltage higher than the operating voltage of the light emitting element is applied. Protection circuits and electrostatic protection elements that can block the flow of overcurrent can be used. Specifically, a Zener diode can be used.

Although several embodiments according to the present invention have been exemplified above, it goes without saying that the present invention is not limited to the above-described embodiments, and can be arbitrarily adopted without departing from the gist of the present invention. .

REFERENCE SIGNS LIST 1000 light emitting device 10 support member 101 first surface 11 convex portion 102 second surface 20 light emitting element 30 first insulating member 40 wiring 50 wire 60 resin frame 70 coating member 71 wavelength converting member 72 light diffusing material 80 second insulating member 90 protection element

Claims (5)

a first surface, a convex portion surrounding the first surface in plan view and having a height higher than the first surface, and a second surface surrounding the convex portion in plan view and having a height lower than the convex portion and a conductive support member having
a light emitting element placed on the first surface and having a height lower than that of the projection;
a first insulating member placed on the second surface and having a height lower than that of the projection;
wiring placed on the first insulating member;
A part of the side surface of the convex portion that surrounds the first surface in plan view and is positioned on the side of the first insulating member in cross-sectional view; a resin frame that continuously covers the second surface, the side and top surfaces of the first insulating member, and the side and top surfaces of the wiring;
A coating that is in contact with the resin frame and covers the light emitting element, another part of the side surface of the protrusion located on the side of the first insulating member that is not covered by the resin frame, and the upper surface of the protrusion. comprising a member and
A light-emitting device, wherein the convex portion is located at a position that blocks at least part of the light from the light-emitting element that is irradiated onto the resin frame . 2. The light-emitting device according to claim 1, wherein said convex portion is formed by bending said support member. 3. The light-emitting device according to claim 1, further comprising a wire for electrically connecting said light-emitting element and said wiring. 4. The light emitting device according to claim 1, further comprising a protective element partially or wholly covered with the resin frame. A second insulating member placed on the wiring and having a height lower than the protrusion,
The light emitting device according to any one of claims 1 to 4, wherein the resin frame covers the side surface and the upper surface of the second insulating member when viewed in cross section.

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