WO2018155167A1 - Light emitting device and method for manufacturing same - Google Patents

Abstract

Provided are: a light emitting device wherein blackening of a phosphor-containing resin can be suppressed, said blackening being caused by deterioration of the resin due to heat; and a method for manufacturing the light emitting device. This light emitting device is characterized by being provided with: a package 10; a light source 3, which is disposed on a bottom section 10a of the package 10, and which emits excitation light L1; a first resin layer 1 that seals the light source 3; a second resin layer 2, which contains a phosphor material 4 that converts the wavelength of the excitation light L1, and which is provided on the first resin layer 1; and a transparent heat dissipating member 5 that is provided between the first resin layer 1 and the second resin layer 2.

Description

Light emitting device and manufacturing method thereof

The present invention relates to a light emitting device using an excitation light source such as LED (Light Emitting Diode) or LD (Laser Diode), and a method for manufacturing the same.

In recent years, attention has been focused on light-emitting devices using LEDs and LDs as next-generation light sources to replace fluorescent lamps and incandescent lamps. As an example of such a next-generation light source, a light-emitting device that combines an LED that emits blue light and a wavelength conversion member that absorbs part of the light from the LED and converts it into yellow light is disclosed. This light emitting device emits white light that is a combined light of blue light emitted from the LED and transmitted through the wavelength conversion unit and yellow light emitted from the wavelength conversion unit. Patent Document 1 discloses a wavelength conversion unit in which a resin in which a phosphor is dispersed is arranged in a package as an example of a wavelength conversion unit.

Japanese Patent Laying-Open No. 2015-220330

The present inventors have found that when a wavelength conversion part made of a resin containing a phosphor is used, there is a problem that when used for a long time, the resin deteriorates and becomes black due to heat and the emission intensity decreases.

An object of the present invention is to provide a light-emitting device capable of suppressing deterioration and blackening of a resin containing a phosphor due to heat, and a method for manufacturing the same.

The light emitting device of the present invention includes a package, a light source that emits excitation light, a first resin layer that seals the light source, and a phosphor that converts the wavelength of the excitation light. It is characterized by comprising a second resin layer provided on one resin layer and a transparent heat dissipating member provided between the first resin layer and the second resin layer.

The transparent heat radiating member is preferably made of glass or ceramic.

In the present invention, it is preferable that a transparent heat dissipating member is provided so as to cover an excitation light irradiation region between the first resin layer and the second resin layer. In this case, the area of the transparent heat radiating member is preferably at least twice the area of the excitation light irradiation region.

In the present invention, the difference in refractive index between the transparent heat radiating member and the respective resins constituting the first resin layer and the second resin layer is preferably 0.4 or less. Here, the refractive index indicates a value at a wavelength of 587 nm.

In the present invention, another transparent heat radiating member may be provided also on the light emitting side of the second resin layer.

A first manufacturing method of the present invention is a method for manufacturing the light emitting device of the present invention, wherein a step of arranging a light source at the bottom of the package, a step of sealing the light source with a first resin layer, A step of disposing a transparent heat dissipating member on the resin layer of 1, a step of introducing a pre-curing resin for forming the second resin layer on the transparent heat dissipating member, and curing the resin before curing And a step of forming a second resin layer.

A second manufacturing method of the present invention is a method of manufacturing the light emitting device of the present invention, wherein a step of arranging a light source at the bottom of the package, a step of sealing the light source with a first resin layer, And a step of disposing a second resin layer in a cured state in which a transparent heat radiating member is attached on the lower side of the resin layer.

According to the light emitting device of the present invention, it is possible to suppress the resin containing the phosphor from being deteriorated by heat and being blackened.

FIG. 1 is a schematic cross-sectional view showing a light emitting device according to a first embodiment of the present invention. FIG. 2 is a schematic cross-sectional view for explaining the area of the transparent heat radiating member in the embodiment shown in FIG. FIG. 3 is a schematic cross-sectional view showing a light emitting device according to a second embodiment of the present invention. FIG. 4 is a schematic cross-sectional view showing a light emitting device according to a third embodiment of the present invention. FIG. 5 is a schematic cross-sectional view showing an example of the second resin layer in the embodiment of the second production method of the present invention. FIG. 6 is a schematic cross-sectional view showing another example of the second resin layer in the embodiment of the second production method of the present invention.

Hereinafter, preferred embodiments will be described. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. Moreover, in each drawing, the member which has the substantially the same function may be referred with the same code | symbol.

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing a light emitting device according to a first embodiment of the present invention. As shown in FIG. 1, the light emitting device 21 of the present embodiment includes a package 10, a light source 3 disposed on the bottom 10 a of the package 10, a first resin layer 1 provided in the package 10, and a package 10. The second resin layer 2 provided above the first resin layer 1 and the transparent heat dissipating member 5 provided between the first resin layer 1 and the second resin layer 2 in the package 10 are provided. Yes. The light source 3 is sealed with a resin 1 a constituting the first resin layer 1. The second resin layer 2 includes a phosphor 4. The phosphor 4 is included in the form of particles, and is dispersed in the resin 2 a constituting the second resin layer 2. The opening 10 b of the package 10 is sealed with a lid material 11.

Excitation light L1 is emitted from the light source 3 provided in the first resin layer 1. The excitation light L1 passes through the transparent heat radiating member 5 and is emitted to the second resin layer 2. The phosphor 4 provided in the second resin layer 2 converts the wavelength of the excitation light L1 and emits fluorescence. The combined light L2 of the fluorescence emitted from the phosphor 4 and the excitation light L1 transmitted through the second resin layer 2 is emitted from the light emitting device 21 through the lid member 11.

The excitation light L1 excites the phosphor 4 to emit fluorescence, and a part thereof is converted into thermal energy. For this reason, the resin 2a constituting the second resin layer 2 is heated by irradiation with the excitation light L1. The present inventors have found that there is a problem that the resin 2a deteriorates due to this heat, the second resin layer 2 becomes black, and the light emission intensity decreases. Moreover, the light emission characteristics of the phosphor 4 included in the second resin layer 2 are also reduced by this heat.

In the present embodiment, a transparent heat radiating member 5 is provided between the first resin layer 1 and the second resin layer 2. For this reason, the heat generated in the second resin layer 2 can be diffused, and local heating in the second resin layer 2 can be suppressed. In particular, since the energy distribution of the excitation light L1 is usually high in the central portion, the thermal energy generated in the central portion of the excitation light L1 tends to increase. Therefore, by providing the transparent heat radiating member 5 between the first resin layer 1 and the second resin layer 2, the heat generated in the central portion of the excitation light L1 can be diffused to the peripheral portion. Therefore, in this embodiment, it can suppress that the 2nd resin layer 2 deteriorates by heat and blackens, and can suppress that emitted light intensity falls. It is preferable that at least a part of the peripheral edge of the transparent heat radiating member 5 is in contact with the package 10. In this way, the generated heat can be efficiently released to the outside.

FIG. 2 is a schematic cross-sectional view for further explaining the transparent heat dissipating member 5 in the present embodiment. As shown in FIG. 2, the area S1 of the transparent heat radiating member 5 in this embodiment is larger than the area S2 of the irradiation region of the excitation light L1. For this reason, the transparent heat radiating member 5 can cover the irradiation region of the excitation light L <b> 1 between the first resin layer 1 and the second resin layer 2. The area S1 of the transparent heat radiating member 5 is preferably 1.1 times or more, more preferably 1.3 times or more, and 1.5 times or more as large as the area S2 of the irradiation region of the excitation light L1. Is more preferably 2 times or more, particularly preferably 3 times or more, and most preferably 4 times or more. Thereby, the heat generated in the second resin layer 2 can be diffused more effectively. The transparent heat radiating member 5 can also diffuse the heat in the first resin layer 1 generated by the irradiation of the excitation light L1.

The material of the transparent heat dissipating member 5 transmits the excitation light L1 (further emitted from the phosphor 4), and the resin 1a constituting the first resin layer 1 and the resin 2a constituting the second resin layer 2. Any material having higher thermal conductivity can be used without any particular limitation. The thermal conductivity of the transparent heat radiating member 5 is preferably 1 W / mK or more, more preferably 3 W / mK or more, further preferably 5 W / mK or more, and particularly preferably 10 W / mK or more. preferable. Such materials include glass and ceramic. Examples of the glass include SiO ₂ —B ₂ O ₃ —RO (R is Mg, Ca, Sr, or Ba) glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O (R ′ is Li, Na, or K). ) -Based glass or SiO ₂ —B ₂ O ₃ —RO—R ′ ₂ O-based glass. As the SiO ₂ —B ₂ O ₃ —RO based glass, for example, “OA-10G” (thermal conductivity 1 W / mK) manufactured by Nippon Electric Glass Co., Ltd. is suitable. As the ceramic, a high thermal conductive ceramic can be used. Examples of high thermal conductive ceramics include aluminum oxide ceramics, aluminum nitride ceramics, silicon carbide ceramics, boron nitride ceramics, magnesium oxide ceramics, titanium oxide ceramics, niobium oxide ceramics, zinc oxide ceramics, and oxides. Examples thereof include yttrium-based ceramics.

The thickness of the transparent heat dissipating member 5 can be appropriately determined in consideration of the transparency of the excitation light L1, the thermal conductivity, and the like. The thickness of the transparent heat radiating member 5 is, for example, preferably in the range of 0.001 mm to 1 mm, more preferably in the range of 0.01 mm to 0.5 mm, and in the range of 0.05 mm to 0.2 mm. More preferably.

As the light source 3, for example, an LED light source or an LD light source that emits blue light as excitation light L1 is used. When the excitation light L1 is blue light, for example, yellow light is emitted as fluorescence from the phosphor 4, and white light is emitted as the excitation light L1 and the combined light L2 of fluorescence. Alternatively, when the excitation light L1 is blue light, the phosphor 4 that emits green light and the light that emits red light are mixed and used, so that the excitation light L1 and the fluorescence combined light L2 are white. Light is emitted.

As the resin 1a constituting the first resin layer 1, for example, a curable resin such as a translucent ultraviolet curable resin or a thermosetting resin is used. Specifically, for example, an epoxy resin, an acrylic resin, a silicone resin, or the like can be used. As the resin 2a constituting the second resin layer 2, the same resin as the resin 1a can be used.

The difference in refractive index between the transparent heat radiating member 5 and the respective resins 1a and 2a constituting the first resin layer 1 and the second resin layer 2 is preferably 0.4 or less, and 0.3 or less. More preferably, it is more preferably 0.2 or less. By reducing the difference in refractive index, the reflection of the excitation light L1 at the interface between the transparent heat dissipation member 5 and the first resin layer 1 and / or the interface between the transparent heat dissipation member 5 and the second resin layer 2 is reduced. The light emission efficiency and the light extraction efficiency can be increased.

As the phosphor 4 included in the second resin layer 2, for example, quantum dots can be used. Examples of quantum dots include II-VI group compounds and III-V group compounds. Examples of the II-VI group compound include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe and the like. Examples of the III-V group compound include InP, GaN, GaAs, GaP, AlN, AlP, AlSb, InN, InAs, and InSb. At least one selected from these compounds, or a composite of two or more of these can be used as quantum dots. Examples of the composite include those having a core-shell structure, such as those having a core-shell structure in which the surface of CdSe particles is coated with ZnS.

The phosphor 4 is not limited to quantum dots. For example, an oxide phosphor, a nitride phosphor, an oxynitride phosphor, a chloride phosphor, an acid chloride phosphor, a sulfide phosphor, an acid Inorganic phosphor particles such as a sulfide phosphor, a halide phosphor, a chalcogenide phosphor, an aluminate phosphor, a halophosphate phosphor, or a garnet compound phosphor may be used.

The package 10 can be made of, for example, ceramic or glass. Examples of the ceramic include aluminum oxide, aluminum nitride, zirconia, and mullite. Further, the ceramic may be a glass ceramic such as LTCC (Low Temperature Co-fired Ceramics). Specific examples of LTCC include a sintered body of an inorganic powder such as titanium oxide or niobium oxide and a glass powder. Examples of the glass include SiO ₂ —B ₂ O ₃ —RO (R is Mg, Ca, Sr, or Ba) glass, SiO ₂ —B ₂ O ₃ —R ′ ₂ O (R ′ is Li, Na, or K). ) Based glass, SiO ₂ —B ₂ O ₃ —RO—R ′ ₂ O based glass, SnO—P ₂ O ₅ based glass, TeO ₂ based glass or Bi ₂ O ₃ based glass.

The lid member 11 can be made of a transparent material such as glass, for example. As the glass, the same material as the glass constituting the package 10 can be used.

In the present embodiment, since the transparent heat radiating member 5 is provided between the first resin layer 1 and the second resin layer 2, the heat generated in the second resin layer 2 by the irradiation of the excitation light L1. Can be diffused by the transparent heat dissipating member 5, and the second resin layer 2 can be prevented from being deteriorated by heat and blackened.

In the present embodiment, the transparent heat radiating member 5 is provided so as to be in contact with the first resin layer 1 and the second resin layer 2, but the present invention is not limited to this, and the transparent heat radiating member 5 and the first resin layer 1 are not limited thereto. A gap may be formed between the resin layer 1 and / or between the transparent heat radiating member 5 and the second resin layer 2.

(Second Embodiment)
FIG. 3 is a schematic cross-sectional view showing a light emitting device 22 according to the second embodiment of the present invention. As shown in FIG. 3, in this embodiment, the transparent heat radiating member 5 is not provided in the area | region of the outer periphery between the 1st resin layer 1 and the 2nd resin layer 2. As shown in FIG. Therefore, the first resin layer 1 and the second resin layer 2 are provided in contact with each other in the region of the outer peripheral edge. Other configurations are the same as those of the first embodiment.

Also in this embodiment, since the transparent heat radiating member 5 is provided between the first resin layer 1 and the second resin layer 2, the heat generated in the second resin layer 2 due to the irradiation of the excitation light L1. Can be diffused by the transparent heat dissipating member 5, and the second resin layer 2 can be prevented from being deteriorated by heat and blackened. In this embodiment, the peripheral portion of the transparent heat radiating member 5 is not in contact with the package 10, but the heat conducted to the peripheral portion of the transparent heat radiating member 5 is conducted through the first resin layer 1 or the second resin layer 2. Then, it is discharged to the package 10 and further to the outside. That is, even when the peripheral edge of the transparent heat radiating member 5 is not in contact with the package 10, the effect of improving heat dissipation can be obtained in that the generated heat is conducted to the vicinity of the package 10.

(Third embodiment)
FIG. 4 is a schematic cross-sectional view showing a light emitting device 23 according to the third embodiment of the present invention. As shown in FIG. 4, in the present embodiment, another transparent heat radiating member 6 is also provided on the light emitting side of the second resin layer 2. The transparent heat radiating member 6 can be configured in the same manner as the transparent heat radiating member 5. Other configurations are the same as those of the first embodiment.

In the present embodiment, since another transparent heat radiating member 6 is also provided on the light emitting side of the second resin layer 2, the heat generated in the second resin layer 2 by the irradiation of the excitation light L1 is radiated transparently. It can diffuse effectively with the members 5 and 6, and it can further suppress that the 2nd resin layer 2 deteriorates by heat and blackens.

In the present embodiment, the lid member 11 is provided, but the transparent heat radiating member 6 may function as the lid member and the lid member 11 may not be provided. In this case, the package 10 is sealed by the transparent heat radiating member 6.

(Embodiment of First Manufacturing Method)
An embodiment of the first manufacturing method will be described with reference to FIG. The package 10 is prepared, and the light source 3 is disposed on the bottom 10 a of the package 10. Next, the uncured resin 1a is introduced into the package 10, and the light source 3 is covered with the resin 1a. Next, the resin 1a is cured to form the first resin layer 1.

The transparent heat dissipating member 5 is disposed on the first resin layer 1 in the package 10. At this time, it is preferable to arrange the transparent heat radiating member 5 so that at least a part of the peripheral edge thereof is in contact with the inner wall of the package 10. Next, an uncured resin 2 a for forming the second resin layer 2 is introduced on the transparent heat radiating member 5 in the package 10. The phosphor 4 is dispersed and contained in the resin 2a before curing. Next, the resin 2a is cured to form the second resin layer 2. Next, the opening 10 b of the package 10 is sealed with the lid 11.

As described above, the light emitting device 21 of the first embodiment can be manufactured according to the first manufacturing method of the present invention.

(Embodiment of Second Manufacturing Method)
FIG. 5 is a schematic cross-sectional view showing an example of the second resin layer in the embodiment of the second production method of the present invention. In the first manufacturing method, the second resin layer 2 is formed by introducing the uncured resin 2a into the package 10 and curing the resin 2a in the package 10 as described above. In the second manufacturing method, the cured second resin layer 2 with the transparent heat radiating member 5 attached below as shown in FIG. 5 is disposed on the first resin layer 1 in the package 10. Thus, a light emitting device is manufactured.

The cured second resin layer 2 to which the transparent heat radiating member 5 is attached below can be manufactured as follows. A mold is prepared, the transparent heat radiating member 5 is disposed at the bottom of the mold, the uncured resin 2a is injected thereon, and then the resin 2a is cured to form the second resin layer 2. Thus, the 2nd resin layer 2 of the hardening state to which the transparent heat radiating member 5 was attached below is obtained.

FIG. 6 is a schematic cross-sectional view showing another example of the second resin layer in the embodiment of the second production method of the present invention. In the 2nd resin layer 2 shown in FIG. 6, the transparent heat radiating member 5 is attached below, and another transparent heat radiating member 6 is attached above. By disposing the cured second resin layer 2 shown in FIG. 6 on the first resin layer 1 in the package 10, the light emitting device 23 shown in FIG. 4 can be manufactured.

The second resin layer 2 in the cured state shown in FIG. 6 is a transparent heat radiating member formed thereon after injecting the resin 2a into the mold in the manufacturing method of the second resin layer 2 in the cured state shown in FIG. 6 can be disposed, and then the resin 2a can be cured.

DESCRIPTION OF SYMBOLS 1 ... 1st resin layer 1a ... Resin 2 ... 2nd resin layer 2a ... Resin 3 ... Light source 4 ... Phosphor 5 ... Transparent heat radiation member 6 ... Transparent heat radiation member 10 ... Package 10a ... Bottom part 10b ... Opening part 11 ... Cover Material 21 ... Light emitting device 22 ... Light emitting device 23 ... Light emitting device L1 ... Excitation light L2 ... Synthetic light S1 ... Area of transparent heat radiation member S2 ... Area of excitation light irradiation region

Claims (8)

Package and
A light source that emits excitation light, disposed at the bottom of the package;
A first resin layer for sealing the light source;
A phosphor that converts the wavelength of the excitation light; a second resin layer provided on the first resin layer;
A transparent heat dissipating member provided between the first resin layer and the second resin layer;
A light emitting device comprising: The light emitting device according to claim 1, wherein the transparent heat dissipating member is made of glass or ceramic. The light emitting device according to claim 1 or 2, wherein the transparent heat dissipating member is provided so as to cover an irradiation region of the excitation light between the first resin layer and the second resin layer. The light emitting device according to claim 3, wherein an area of the transparent heat radiating member is at least twice as large as an area of the irradiation region. The refractive index difference between the transparent heat radiating member and each of the resins constituting the first resin layer and the second resin layer is 0.4 or less. The light emitting device according to 1. The light emitting device according to any one of claims 1 to 5, wherein another transparent heat dissipating member is also provided on the light emitting side of the second resin layer. A method for producing a light-emitting device according to any one of claims 1 to 6,
Placing the light source on the bottom of the package;
Sealing the light source with the first resin layer;
Disposing the transparent heat radiating member on the first resin layer;
Introducing a resin before curing for forming the second resin layer on the transparent heat dissipation member,
Curing the uncured resin to form the second resin layer;
A method for manufacturing a light-emitting device. A method for producing a light-emitting device according to any one of claims 1 to 6,
Placing the light source on the bottom of the package;
Sealing the light source with the first resin layer;
Placing the second resin layer in a cured state with the transparent heat dissipating member attached below on the first resin layer;
A method for manufacturing a light-emitting device.

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