WO2019010910A1

WO2019010910A1 - Wavelength conversion device and light source

Info

Publication number: WO2019010910A1
Application number: PCT/CN2017/114713
Authority: WO
Inventors: 田梓峰; 许颜正
Original assignee: 深圳市光峰光电技术有限公司
Priority date: 2017-07-13
Filing date: 2017-12-06
Publication date: 2019-01-17
Also published as: CN109424944A

Abstract

Disclosed are a wavelength conversion device (100) and a preparation method therefor, and a light source. The wavelength conversion device (100) comprises a light-emitting layer (101), a glass bonding layer (102), a silver reflective layer (103), a setter substrate (104), a silver bonding layer (105), a welding layer (106) and a heat conducting substrate (107) being successively superposed, wherein the light-emitting layer (101) is an inorganic light-emitting layer capable of absorbing light within a certain wavelength range and emitting light within a different wavelength range. The wavelength conversion device (100) has the characteristics of high reflectivity, low thermal resistance and high long-term reliability.

Description

Wavelength conversion device and light source

Technical field

The present application relates to the field of illumination and display, and in particular to a wavelength conversion device, a method for fabricating the same, and a light source.

Background technique

At present, the laser fluorescence conversion type light source has developed rapidly and has been widely used in the fields of illumination and projection display. As the brightness requirement of the light source is continuously increased, the laser power is also increased, whereby the wavelength conversion device generates more heat during the illumination process, and when the temperature reaches a certain temperature, the conversion efficiency of the wavelength conversion material increases with the temperature. High and low, resulting in thermal quenching. Therefore, for high-power laser sources, efficient heat dissipation from the wavelength conversion device is necessary.

A conventional wavelength conversion device adopts a light-emitting layer, a reflective layer and a substrate which are sequentially stacked. The reflective layer of the wavelength conversion device is a diffuse reflection layer formed by mixing and sintering white scattering particles and glass frit. Although the diffuse reflection layer is composed entirely of inorganic materials, the heat resistance is high, but the thermal conductivity of the scattering particles and the glass powder in the sintered material is low; and the sintered structure is generally a porous structure in order to ensure a high reflectance. The thermal resistance is high; thus, it is not conducive to heat dissipation of the wavelength conversion device under high power laser excitation, which is disadvantageous to the improvement of the luminance and stability of the wavelength conversion device. Therefore, the diffuse reflection layer of the wavelength conversion device of the solution becomes a bottleneck for further increasing the brightness of the laser fluorescent display source.

Another solution of the existing wavelength conversion device is to replace the diffuse reflection layer with a silver reflective layer on the basis of the above scheme. The advantage of this scheme is that the reflectivity and thermal conductivity of the silver reflective layer are higher than that of the diffuse reflection layer, which is beneficial to improve the light extraction efficiency, brightness and thermal stability of the wavelength conversion device. However, at present, the above solution cannot obtain a silver reflective layer reflecting surface with a high surface flatness, thereby further limiting the reflectance. Therefore, its luminous efficiency efficiency needs to be further improved.

Therefore, there is a need to develop a wavelength conversion device having high reflectance, low thermal resistance, and high reliability.

Summary of the invention

Based on the above problems, the present application aims to provide a wavelength conversion device having high reflectance, low thermal resistance, and high reliability, particularly a wavelength conversion device suitable for a high power laser light source.

Further, a method of preparing the above-described wavelength conversion device and a light source to which the above-described wavelength conversion device is applied are also provided.

The invention adopts the following technical solutions:

A wavelength conversion device comprising a light-emitting layer, a glass bonding layer, a silver reflective layer, and a bearing layer which are sequentially stacked Burning a substrate, a silver bonding layer, a soldering layer, and a thermally conductive substrate;

Wherein, the luminescent layer is an inorganic luminescent layer capable of absorbing light of a certain wavelength range and emitting light of different wavelength ranges. Preferably, the light emitting layer is any one of a light emitting ceramic, a light emitting ceramic single crystal, a light emitting ceramic eutectic or a luminescent glass.

Preferably, the luminescent ceramic is a garnet-structured (Lu, Y, Gd, Tb) ₃ (Ga, Al) ₅ O ₁₂ : Ce ^{3 +} luminescent ceramic, or Al ₂ O ₃ - (Lu, Y, Gd, Tb) ₃ (Ga, Al) ₅ O ₁₂ :Ce ³⁺ composite ceramic.

Preferably, the luminescent ceramic single crystal is a garnet-structured (Lu, Y, Gd, Tb) ₃ (Ga, Al) ₅ O ₁₂ : Ce ^{3 +} luminescent ceramic single crystal.

Preferably, the luminescent ceramic eutectic is a composite ceramic eutectic of Al ₂ O ₃ -(Lu,Y,Gd,Tb) ₃ (Ga,Al) ₅ O ₁₂ :Ce ³⁺ .

Preferably, the luminescent glass is a luminescent glass of a first glass-encapsulated phosphor.

Preferably, the glass bonding layer is a second glass that is transparent.

Preferably, the glass bonding layer is formed by sintering a second glass frit and an organic carrier to form a glass paste.

Preferably, the second glass in the glass bonding layer is glass which does not undergo a color change reaction with the Ag element.

Preferably, the second glass is a silicate or borosilicate lead-free glass; further preferably, it does not contain any of Cu, Sn and Sb.

Further preferably, the second glass has a refractive index of less than 1.6.

Still more preferably, the second glass has a refractive index of less than 1.5.

The glass bonding layer has a thickness of 0.1 to 100 μm; preferably, the thickness is 0.2 to 30 μm, and even more preferably, the thickness is 0.5 to 10 μm.

Wherein, the silver reflective layer and/or the silver bonding layer is a pure silver layer or a composite silver layer containing silver and a third glass.

Preferably, the silver reflective layer and/or the silver bonding layer are formed by sintering silver powder and an organic carrier to form a silver paste, or sintering the silver powder, the third glass powder and the organic carrier into a silver paste.

Preferably, the silver reflective layer and/or the silver bonding layer has a thickness of 1 to 100 μm.

Preferably, the silver powder has a particle size ranging from 0.01 to 20 μm; the silver powder is preferably spherical or flake-shaped.

Preferably, the glass bonding layer completely covers the reflective surface and the side surface of the silver reflective layer.

The sapphire substrate is preferably any one of an alumina ceramic substrate, a sapphire substrate, a boron nitride substrate, a metal tungsten substrate, or a metal molybdenum substrate.

Preferably, the thickness of the under-fired substrate is 0.1 to 5 mm, and more preferably 0.2 to 1 mm.

Wherein, the solder layer is a solder layer or a sintered silver layer. Further preferably, the solder layer is formed by at least one or a combination of gold tin, silver tin, antimony tin or lead solder, or reflow soldering of the preformed soldering piece.

Preferably, the solder layer has a thickness of 0.005 to 0.5 mm.

Preferably, the thermally conductive substrate is a metal substrate or a ceramic substrate. Preferably, the thermally conductive substrate is any one of copper, aluminum, aluminum nitride, silicon carbide, silicon nitride or alumina ceramic substrates.

Preferably, the thermally conductive substrate has a thickness of 0.1 to 5 mm.

Preferably, the periphery of the side of the wavelength conversion device is at least partially covered with a sealing layer.

Further preferably, the sealing layer completely surrounds the side of the coated silver reflective layer.

Preferably, the sealing layer is any one or a combination of epoxy resin, silicone resin or silica gel.

Preferably, the encapsulating layer has an oxygen permeability of less than 500 cc/m ² .day; further preferably, the oxygen permeability is less than 300 cc/m ² .day; particularly preferably, the oxygen permeability is less than 100 cc/m ² .day .

Preferably, the surface of the copper substrate or the aluminum substrate is plated with a nickel-gold protective layer.

Preferably, the surface of the alumina ceramic and ceramic substrate is coated with a titanium transition layer, and then a nickel-gold protective layer is plated.

Preferably, the thermally conductive substrate is of a flat type or a fin type.

Preferably, the first surface of the light emitting layer is provided with an antireflection film or a surface roughening.

The invention also provides a preparation method of the above wavelength conversion device, which comprises the following steps:

Step A: coating silver paste on one side of the substrate to be baked, and then drying; then, coating the silver paste on the other side of the substrate to be dried, and then sintering at a high temperature to form a silver reflective layer on one side of the substrate. On the other side, a silver bonding layer is formed.

Among them, the silver paste is a mixed slurry of silver powder and an organic carrier or a mixed slurry of silver powder, a third glass and an organic vehicle. The drying temperature is 60 to 150 °C. The high temperature sintering temperature is 500 to 1000 °C.

Step B: coating a second glass paste on the silver reflective layer; the luminescent layer is placed on the second glass paste, and then dried and sintered at a high temperature to obtain a stacked luminescent layer, a glass bonding layer, a silver reflective layer, The substrate is sintered and the silver bonding layer.

The second glass paste is a mixed slurry of the second glass frit and the organic vehicle.

Step C: Coating a solder on the silver bonding layer and then soldering it onto the thermally conductive substrate to prepare a wavelength conversion device.

Among them, the welding method is preferably reflow soldering.

As a preferred embodiment,

Further after step C, step D is further included: applying a sealant paste around the side of the wavelength conversion device to cure to form a seal layer.

Among them, curing at ultraviolet or high temperature is preferred.

The invention also provides a light source comprising the above wavelength conversion device, the light source further comprising an excitation light source, the excitation light source being a laser source, a laser diode source, a light emitting diode or a laser At least one or a combination of a light tube array and a light source diode array.

The beneficial effects of the invention are:

Since the reflective layer of the above-mentioned wavelength conversion device is a silver reflective layer, and the silver reflective layer is obtained by high-temperature sintering of an alumina substrate or the like as a high-temperature setter, the reflective surface of the silver reflective layer is in a free sintered state during sintering, that is, the reflection In the process of surface sintering, there is no other substrate directly in contact with it. The silver paste is not limited in the sintering process, which is beneficial to the flow of the silver paste during the sintering process to form a dense silver layer; at the same time, the reflective surface is not affected. The surface flatness of the other substrate is also greatly improved by the surface roughness or the influence of the pores; therefore, the wavelength conversion device of the present invention can form a silver reflective layer having a high density and a very high surface flatness during the preparation process. The compactness and surface flatness of the silver reflective layer are high. On the one hand, the dense and flat silver reflective layer can have a very high reflectivity, which can improve the light-emitting efficiency of the wavelength conversion device; on the other hand, the dense silver reflective layer has a very high The thermal conductivity reduces the thermal resistance of the wavelength conversion device. At the same time, the solder layer also has a high thermal conductivity, and the thermal conductive substrate welded with it improves the thermal conductivity of the entire wavelength conversion device. Increased reliability in high power laser applications. Further, by optimizing the specific parameters, the bonding strength between the layers is improved, and the reliability in the application of the high-speed color wheel is improved.

DRAWINGS

1 is a schematic structural view of a wavelength conversion device prepared in Embodiment 1;

2 is a schematic structural view of a wavelength conversion device prepared in Embodiment 2;

3 is a schematic structural view of a wavelength conversion device prepared in the third embodiment;

4 is a schematic structural view of a wavelength conversion device prepared in Embodiment 4;

FIG. 5 is a schematic structural view of a wavelength conversion device prepared in the fifth embodiment.

Detailed ways

In order to facilitate the understanding of the present invention, the present invention will be described in detail below with reference to the specific embodiments and drawings. The invention is capable of a variety of different embodiments and is not limited to the embodiments described herein. The terms "first," "second," and "third," and the like, are used in the context of the description and understanding, and are not intended to limit the invention. The content of each part is different, and the omitted part can be referred to other parts.

As shown in FIG. 1, the wavelength conversion device 100 includes a light-emitting layer 101, a glass bonding layer 102, a silver reflective layer 103, a substrate 140, a silver bonding layer 105, a solder layer 106, and a heat-conducting substrate 107 which are sequentially stacked.

Wherein, the luminescent layer is an inorganic luminescent layer capable of absorbing light of a certain wavelength range and emitting light of different wavelength ranges.

As a preferred embodiment, the luminescent layer 101 is a luminescent ceramic, a luminescent ceramic single crystal, and a luminescent ceramic. Any of eutectic or luminescent glass.

As a preferred embodiment, the light-emitting layer 101 is a garnet-structured (Lu, Y, Gd, Tb) ₃ (Ga, Al) ₅ O ₁₂ : Ce ^{3 +} luminescent ceramic, (Lu, Y, Gd, Tb) ₃ ( Ga,Al) ₅ O ₁₂ :Ce ³⁺ luminescent ceramic single crystal, Al ₂ O ₃ -(Lu,Y,Gd,Tb) ₃ (Ga,Al) ₅ O ₁₂ :Ce ³⁺ composite ceramic or Al ₂ O ₃ - (Lu, Y, Gd, Tb) ₃ (Ga, Al) ₅ O ₁₂ : Any of the Ce ^{3 +} eutectic.

As still another preferred embodiment, the light-emitting layer 101 may be a light-emitting glass of a first glass-encapsulated phosphor.

In a specific embodiment, YAG:Ce ³⁺ luminescent ceramic or YAG:Ce ³⁺ single crystal, YAG:Ce ^{3+ is a} garnet structure of Y ₃ Al ₅ O ₁₂ :Ce ³⁺ . It should be noted that the conventional light-emitting layer, such as a silica gel-encapsulated phosphor, an organic gel-encapsulated phosphor, or the like, has a low-temperature resistance performance and is generally not considered for use in the application of the present invention. In contrast, luminescent ceramics and luminescent glass have good mechanical properties and high temperature stability, especially excellent mechanical properties, which can further perform mechanical processing such as grinding and polishing, and can ensure the implementation of subsequent process steps.

Further, the thickness of the light-emitting layer 101 is 0.005 to 1 mm. In some other embodiments, the luminescent layer 101 has a thickness of 0.05 to 0.5 mm.

The glass bonding layer 102 is a transparent second glass. The glass bonding layer 102 is formed by mixing a second glass frit and an organic carrier to form a glass paste. Further, the second glass in the glass bonding layer 102 is glass which does not undergo a color change reaction with the Ag element. Specifically, the second glass is a silicate or borosilicate lead-free glass; further preferably, it does not contain any of Cu, Sn, and Sb.

Further, the second glass has a refractive index lower than 1.6. Further, the second glass has a refractive index of less than 1.5.

It should be noted here that the refractive index of the matrix in the luminescent ceramic is relatively high, such as the common YAG:Ce ³⁺ up to 1.84; we found that the refractive index of the encapsulation material in the YAG luminescent ceramic is closer to YAG, under the high-power excitation light source. The better the saturation of the light. The reason is that the closer the refractive index of the encapsulating material is to YAG, the less the reflection loss of light between the encapsulating material and the YAG interface; at present, most of the glass which does not contain elements such as Cu, Co, Sn and Sb which can react with silver. The refractive index is relatively low; therefore, the advantage of using the low refractive index glass bonding layer 102 is that on the one hand, the higher luminous efficiency of the luminescent layer can be ensured, and the luminescent layer 101 is prevented from directly contacting the reflective silver layer 103 to cause discoloration. The phenomenon ensures optical reliability during long-term use; on the other hand, the glass bonding layer 102 can bond the silver reflective layer 103 and the light-emitting layer with high strength to ensure the mechanical reliability of the wavelength conversion device.

At the same time, in order to ensure the thermal conductivity of the wavelength conversion device, the thickness of the glass bonding layer should not be too thick; too thick will reduce the thermal conductivity of the wavelength conversion device. The glass bonding layer has a thickness of 0.1 to 100 μm; preferably, the thickness is 0.2 to 30 μm, and even more preferably, the thickness is 0.5 to 10 μm.

It can be understood that, as other embodiments, when the luminescent layer 101 is the first glass-encapsulated phosphor In the case of illuminating glass, at this time, the glass bonding layer 102 may be omitted, that is, the luminescent layer 101 is directly in contact with the silver reflecting layer 103. At the same time, the first glass should also be similar to the choice of the second glass. For the specific selection method, please refer to the second glass.

The silver reflective layer 103 and/or the silver bonding layer 105 is a pure silver layer or a composite silver layer containing silver and a third glass. Preferably, the silver reflective layer and/or the silver bonding layer are formed by sintering silver powder and an organic carrier to form a silver paste, or sintering the silver powder, the third glass powder and the organic carrier into a silver paste.

In some embodiments, the thickness of the silver reflective layer 103 and/or the silver bonding layer 105 is from 1 to 100 μm. It should be noted that, when the thickness of the silver reflective layer is less than 1 μm, the silver paste process is not easy to control; when the thickness of the silver reflective layer is greater than 100 μm, it is disadvantageous for sintering to obtain a dense and flat sintered silver surface.

Among them, the raw material silver powder has a particle diameter ranging from 0.01 to 20 μm. The silver powder with a particle size of less than 0.01 μm is not easily dispersed, and the surface flatness of the silver paste prepared by the silver powder having a particle diameter of more than 20 μm is not easily controlled, and the silver powder having a larger particle diameter is less likely to be sintered densely on the alumina substrate, and the adhesion is deteriorated. The raw material silver powder is preferably spherical or flake-shaped, and the two shape particles are favorable for forming a close-packed structure, and the sintered silver reflective layer is more dense.

The under-fired substrate 104 is any one of an alumina substrate, a boron nitride substrate, a metal tungsten substrate, or a metal molybdenum substrate.

In a preferred embodiment, the thickness of the set substrate 104 is 0.1 to 5 mm, and more preferably 0.2 to 1 mm. Since the substrate for bearing is mainly used for carrying silver paste for sintering the surface of the silver reflective layer, it is necessary to consider its influence on the thermal conductivity of the wavelength conversion device; therefore, the thickness thereof needs to be as small as possible; at the same time, it needs to be guaranteed. The bonding strength with the silver reflective layer, so it is preferably a substrate material having a crystal structure similar to silver, and the substrate to be burned is preferably any one of an alumina substrate, a boron nitride substrate, a metal tungsten substrate or a metal molybdenum substrate. in.

It should be noted that the silver reflective layer 103 and the silver bonding layer 105 may be either a pure silver layer or a composite silver layer, and the two may be the same or different; however, the roles of the two are not the same. Among them, the silver reflective layer 103 is mainly intended to reflect excitation light or receive laser light, and needs to have the highest possible reflectivity while ensuring good thermal conductivity; therefore, the silver reflective layer 103 is preferably a pure silver layer. The silver bonding layer 105 mainly functions as a transition between the bearing substrate 104 and the solder layer 106, and can bond the bearing substrate 104 and the solder layer 10 with higher strength; ensuring the wavelength conversion device. Overall mechanical reliability. However, the action mechanism of the silver bonding layer 105 is slightly different from that of the solder layer and the substrate. Among them, the reason why the sintered substrate 104 and the silver bonding layer 105 have a high bonding strength is that the silver in the sintered silver reflective layer is generally in a hexagonal structure, and has the same lattice structure as alumina (sapphire), so that the bonding strength is good. Thus, the substrate for the substrate can be selected from any hexagonal ceramic or metal, such as hexagonal boron nitride ceramics, high temperature resistant tungsten, molybdenum metal, and alumina ceramics. The higher bonding strength between the solder layer 106 and the silver bonding layer 105 is that silver can form a reliable weld seam with the metal soldering layer during the soldering process; the basic principle of soldering It can be seen that the weld bead is composed of an intermetallic compound. Obviously, in this embodiment, the high-purity silver layer can easily form an intermetallic compound with the metal in the solder paste or the preformed solder, thereby forming a reliable weld. Therefore, the silver bonding layer is also preferably a pure silver layer. Among them, the metal component in the solder paste or the preformed soldering piece includes gold tin, silver tin, antimony tin or lead solder.

In some embodiments, the silver reflective layer and/or the silver bonding layer are formed by sintering silver powder and an organic carrier to form a silver paste, or a silver powder, a third glass frit and an organic carrier are mixed to form a silver paste.

Further, the particle size of the silver powder raw material is in the range of 0.01 to 20 μm; the raw material silver powder is preferably spherical or flake-shaped.

The solder layer 106 is a solder layer or a sintered silver layer. Further, the solder layer 106 is at least one or a combination of gold tin, silver tin, antimony tin or lead solder. It can be understood that when the solder layer 106 is selected to be a sintered silver layer, that is, the same as the silver bonding layer, the two layers may be a single layer. That is, in this embodiment, the underfired substrate is directly bonded to the thermally conductive substrate through the silver bonding layer, and the remaining layers are unchanged. In other embodiments, the silver bonding layer can also be replaced with a thermally conductive adhesive, with the remaining layers unchanged.

The heat conductive substrate 107 is a metal substrate or a ceramic substrate.

Preferably, the heat conductive substrate 107 has a thickness of 0.1 to 5 mm.

In some embodiments, the thermally conductive substrate 107 is any one of copper, aluminum, aluminum nitride, silicon carbide, silicon nitride, or alumina ceramic substrates.

Preferably, the surface of the alumina ceramic and ceramic substrate is plated with a titanium transition layer, and then a nickel-gold protective layer is plated.

Preferably, the thermally conductive substrate is of a flat type or a fin type.

As a preferred embodiment, as shown in FIG. 2, the glass bonding layer 202 completely covers the reflective surface and the side surface of the silver reflective layer 203. Obviously, the silver reflective layer 203 is completely surrounded by the glass bonding layer 202 and the substrate, completely isolated from the air. It can be understood that the glass bonding layer 202 completely covers the reflecting surface and the side surface of the silver reflective layer 203 to maximize the isolation of the sealed silver reflective layer 203, on the one hand, preventing contact with the luminescent layer, and on the other hand, preventing it from coming into contact with air. Vulcanization blackening phenomenon. The reflecting surface of the silver reflective layer is a side close to the light emitting layer.

As a preferred embodiment, in order to further improve the service life of the wavelength conversion device, blackening of the silver reflective layer is prevented; as shown in FIG. 3, the side of the wavelength conversion device is at least partially covered with the sealing layer 308. Further, the sealing layer 308 completely covers at least the side of the silver reflective layer. Further, in order to improve the adhesion of the sealing layer 308 on the side of the wavelength conversion device, the heat conductive substrate area needs to be not less than the remaining layers, preferably slightly larger than the remaining layer areas, and a slightly larger portion is used to carry the sealing layer 308. It should be noted that, because the thickness of each functional layer in the present invention is small, the area of each functional layer is the area of one of the planes, for example, the area of the heat conductive substrate is the contact between the heat conductive substrate and the solder layer or the bonding layer. Face product.

In some embodiments, the oxygen permeability of the encapsulation layer is less than 500 cc/m ² .day; further, the oxygen permeability is less than 300 cc/m ² .day; further, the oxygen permeability is less than 100 cc/m ² .day . Specifically, the sealing layer 208 is any one or a combination of epoxy resin, silicone resin, or silica gel.

As a preferred embodiment, the first surface of the light-emitting layer is provided with an anti-reflection film or roughened. The first surface of the light-emitting layer is one surface of the light-emitting layer away from the heat-dissipating substrate; at the same time, the first surface of the light-emitting layer is also the incident and exit surface of the light of the wavelength conversion device. Providing an anti-reflection film or roughening the surface can improve the light efficiency of the wavelength conversion device.

Step A: coating silver paste on one side of the substrate for baking, drying; then, applying silver paste on the other side of the substrate to be baked, drying; then, sintering at a high temperature; forming a silver reflective layer on one side of the alumina substrate On the other side, a silver bonding layer is formed.

In order to ensure the flatness of the sintered silver reflective layer, it is also possible to appropriately stand for a certain period of time after the silver paste is applied.

Among them, the welding method is preferably reflow soldering. The reflow temperature is 280 to 320 °C.

As a preferred embodiment,

Among them, the curing method differs depending on the sealing layer, and is preferably ultraviolet or high temperature curing. Further, the sealing layer glue is completely coated on the side of the wavelength conversion device to improve the sealing effect.

It should be noted that Step A is an important step in the preparation method of the present invention. As described in the background art, in the preparation process of the prior art, the silver reflective layer is prepared by first coating a silver paste on the light-emitting layer, and sintering the light-emitting layer as a carrier to obtain a silver reflective layer. Therefore, the reflecting surface of the silver reflective layer and the luminescent layer are in close contact with each other during the preparation process, and the reflecting surface of the silver reflecting layer is sintered under the limited state of the luminescent layer, and the surface flatness of the silver reflecting layer is formed. Depending on the luminescent layer Surface flatness; even if the surface of the luminescent layer is polished, the surface will also have a certain roughness and pores. Therefore, the solution described in the prior art cannot obtain a silver reflective layer reflecting surface with a high surface flatness, thereby further limiting the reflectance.

The reflective layer of the wavelength conversion device of the present invention is a silver reflective layer, and the silver reflective layer is obtained by high-temperature sintering of an aluminum substrate or the like as a high-temperature setter, and the reflective surface of the silver reflective layer is in a free sintered state during sintering, that is, There is no other substrate in direct contact with the reflective surface during the sintering process. Generally, the sintering process is carried out under a protective atmosphere or in a vacuum. The silver paste is not limited in the sintering process, which is beneficial to the sintering process of the silver paste. Flowing to form a dense silver layer; at the same time, the reflective surface is not affected by the surface roughness or pores of other substrates, and the surface flatness is also greatly improved; thus, the wavelength conversion device of the present invention can be formed during the preparation process. Silver reflective layer with high density and extremely flat surface. The compactness and surface flatness of the silver reflective layer are high. On the one hand, the dense and flat silver reflective layer can have a very high reflectivity, which can improve the light-emitting efficiency of the wavelength conversion device; on the other hand, the dense silver reflective layer has a very high The thermal conductivity reduces the thermal resistance of the wavelength conversion device. Tests have found that the reflective surface reflectance of the silver reflective layer on the substrate is 10% higher than that of the lower surface layer in the free sintered state without any external pressurization.

The solder paste is at least one or a combination of solder pastes of gold tin, silver tin, antimony tin, and lead tin.

The silver powder particle size in the silver reflective layer ranges from 0.01 to 20 μm. Further, the raw material silver powder is spherical or flake-shaped.

Further, in some embodiments, step B further comprises plating the first side of the light-emitting layer with an anti-reflection film or roughening the surface.

As another embodiment, step A may be replaced by step A1: coating silver paste on one side of the substrate to be fired, drying, and sintering at a high temperature; forming a silver reflective layer on one side of the alumina substrate and vacant on the other side.

As still other embodiments, step B may be replaced with step B1: coating a mixed slurry of the second glass and phosphor on the silver reflective layer; then sintering at a high temperature.

Wherein, the mixed slurry of the second glass and the phosphor also includes an organic vehicle. The high temperature sintering temperature is 500 to 1000 °C.

As still another embodiment, step C may be replaced by step C1: coating a thermal conductive adhesive on the silver bonding layer or the substrate, and then bonding to the thermally conductive substrate to prepare a wavelength conversion device.

The present application is further described in detail below by way of specific embodiments. The following examples are only intended to further illustrate the present application and are not to be construed as limiting the invention.

Embodiment 1

In this example, YAG:Ce ³⁺ ceramic is used as the raw material of the light-emitting layer, silicate lead-free glass is used as the second glass raw material, silver paste of pure silver powder and organic carrier is used as the raw material of the silver reflective layer, and the alumina substrate (sapphire substrate) is used as the base. The silver paste of the substrate, the pure silver powder and the organic carrier is used as the raw material of the silver bonding layer, the solder of the soldering layer is gold tin or silver tin, and the heat conductive substrate is selected to be a nickel-plated gold-copper substrate. A wavelength conversion device constructed as in Fig. 1 was prepared.

The specific process is as follows:

Step A: coating silver paste on one side of the substrate to be fired, drying at 60 to 150 ° C; then, applying silver paste on the other side of the substrate to be baked, drying; then, sintering at a high temperature of 500 to 1000 ° C; A silver reflective layer is formed on one surface of the aluminum substrate, and a silver adhesion layer is formed on the other surface. The under-fired substrate selected in this example was an alumina substrate (sapphire substrate) and had a thickness of 1 mm. The silver paste is a mixed slurry of silver powder and an organic carrier. Further, this example was allowed to stand for a while after coating the silver paste.

Step B: coating a second glass paste on the silver reflective layer; the luminescent layer is placed on the second glass paste, and then dried and sintered at a high temperature to obtain a stacked luminescent layer, a glass bonding layer, a silver reflective layer, The substrate is sintered and the silver bonding layer. The drying temperature is 60 to 150 °C. The high temperature sintering temperature is 500 to 1000 °C. In this example, the second glass paste is a mixed slurry of the second glass frit and the organic vehicle, and the silicate lead-free glass is used as the second glass raw material as the second glass raw material.

Step C: Coating a solder on the silver bonding layer and then soldering it onto the thermally conductive substrate to prepare a wavelength conversion device. In this example, the soldering method is preferably reflow soldering. The reflow temperature is 280 to 320 °C. The solder of the solder layer is gold tin or silver tin; the heat conductive substrate is selected from a nickel-plated gold-copper substrate with a thickness of 5 mm.

Wherein, the particle size of the silver powder raw material in the silver reflective layer ranges from 0.01 to 20 μm; the silver powder raw material is spherical or flake-shaped. The silver powder with a particle size of less than 0.01 μm is not easily dispersed, and the surface flatness of the silver paste prepared by the silver powder having a particle diameter of more than 20 μm is not easily controlled, and the silver powder having a larger particle diameter is less likely to be sintered densely on the alumina substrate, and the adhesion is deteriorated. The raw material silver powder is preferably spherical or flake-shaped, and the two shape particles are favorable for forming a close-packed structure, and the sintered silver reflective layer is more dense. The silver powder may also contain platinum powder and/or palladium powder to improve the high temperature migration characteristics of the silver; wherein the palladium and/or platinum powder content does not exceed 30%, otherwise the reflectance may be affected.

The organic vehicle consists of a binder and an organic solvent. Wherein the binder is ethyl cellulose; the solvent is at least one selected from the group consisting of terpineol, butyl carbitol, butyl carbitol, tributyl citrate and acetyl tributyl citrate. Specifically in this embodiment is a mixture of ethyl cellulose and terpineol.

The thickness of the metal solder layer is controlled to be between 0.005 and 0.5 mm; the thickness of the glass bonding layer is controlled to be 0.1 to 100 μm; and the thickness of the silver reflective layer is controlled to be between 1 and 100 μm.

Embodiment 2

In this example, a wavelength conversion device of a similar structure is prepared as in the first embodiment. The difference is that the glass bonding layer 202 in this example completely covers the reflecting surface and the side surface of the silver reflecting layer 203. The structure thereof is as shown in FIG. 2, and the wavelength conversion device includes a light-emitting layer 201, a glass bonding layer 202, a silver reflective layer 203, a substrate 140, a silver bonding layer 205, a solder layer 206, and a heat-conducting substrate which are sequentially stacked. 207; wherein the glass bonding layer 202 completely covers the reflecting surface and the side surface of the silver reflecting layer 203; and the side surface of the silver reflecting layer 203 is also covered by the glass bonding layer 202.

The specific preparation process is as follows:

Step A: coating silver paste on one side of the substrate to be baked, drying at 60 to 150 ° C; then, applying silver paste on the other side of the alumina substrate, drying; then, sintering at a high temperature of 500 to 1000 ° C; A silver reflective layer is formed on one surface of the aluminum substrate, and a silver adhesion layer is formed on the other surface. The under-fired substrate selected in this example was an alumina substrate (sapphire substrate) and had a thickness of 0.2 mm. The silver paste is a mixed slurry of silver powder and an organic carrier.

Step B: coating a second glass paste on the silver reflective layer, the second glass paste completely covering the reflective surface and the side surface of the silver reflective layer; the luminescent layer is placed on the second glass paste, and then dried and sintered at a high temperature A laminated light-emitting layer, a glass bonding layer, a silver reflective layer, a setter substrate, and a silver bonding layer are obtained. The drying temperature is 60 to 150 °C. The high temperature sintering temperature is 500 to 1000 °C. In this example, the second glass paste is a mixed slurry of the second glass frit and the organic vehicle, and the silicate lead-free glass is used as the second glass raw material as the second glass raw material.

For other parts, please refer to the first embodiment.

In this example, since the glass bonding layer completely covers the reflecting surface and the side surface of the silver reflecting layer, the edge portion of the silver reflecting layer is completely isolated from the air, thereby ensuring blackening of the silver reflecting layer during long-term use, thereby ensuring Long-term optical reliability.

Embodiment 3

In this example, a wavelength conversion device of a similar structure is prepared as in the first embodiment. The difference from the first embodiment is that, in addition to the wavelength conversion device produced in the first embodiment, the sealing layer is coated around the side surface thereof. The specific structure is shown in Figure 3. The wavelength conversion device includes a light emitting layer 301, a glass bonding layer 302, a silver reflecting layer 303, a bearing substrate 304, a silver bonding layer 305, a solder layer 306, and a heat conductive substrate 307 which are sequentially stacked; the sealing layer 308 is coated on at least A silver reflective layer 303 is included around the inner side. At the same time, the heat conductive substrate 307 has an area not less than the remaining layers for carrying the sealing layer 308.

The specific preparation process is as follows:

For step A, step B and step C, please refer to the first embodiment.

Wherein, the area of the heat conductive substrate in step C needs to be not less than the area of the remaining layers. Used to carry a sealing layer.

Step D: Apply the sealant paste around the side of the wavelength conversion device to cure to form a sealing layer. In this example, epoxy resin is used as the sealing layer material and cured by ultraviolet curing. It should be noted that the sealing layer needs to completely cover the silver reflective layer as much as possible to ensure that the silver reflective layer does not come into contact with air during long-term use.

Among them, the oxygen permeability of the epoxy resin varies depending on the actual type. In this case, it is less than 500 cc/m ² .day.

In the wavelength conversion device prepared in this example, since a sealing layer is coated around the side on the basis of the first embodiment, the silver reflective layer can be blocked from the air as much as possible, thereby ensuring that the silver reflective layer is black during long-term use. The phenomenon ensures long-term optical reliability.

Embodiment 4

In this example, a wavelength conversion device as shown in FIG. 4 is prepared, including a light-emitting layer 401, a glass bonding layer 402, a silver reflective layer 403, a substrate 404, a silver bonding layer 405, a solder layer 406, and heat conduction which are sequentially stacked. The substrate 407 further includes a sealing layer 408 wrapped around the side surface; wherein the light emitting layer also adopts YAG:Ce ³⁺ ceramic; the glass bonding layer 402 completely covers the reflecting surface and the side surface of the silver reflective layer 403, and the silver reflective layer 403 is ensured. The sides are also covered by a glass bonding layer; at the same time, the thermally conductive substrate 407 has an area not less than the remaining layers for carrying the sealing layer 408. Please refer to other embodiments for the remaining unexpressed parts.

The specific preparation process is as follows:

Step A, please refer to the first embodiment;

For the step C, see the first embodiment;

Step D: Apply the sealant paste around the side of the wavelength conversion device to cure to form a sealing layer. In this example, epoxy resin is used as the sealing layer material and cured by ultraviolet curing. Need note It is intended that the sealing layer needs to completely cover the silver reflective layer as much as possible to ensure that the silver reflective layer does not come into contact with air during prolonged use.

Among them, the oxygen permeability of the epoxy resin varies depending on the actual type.

The wavelength conversion device produced in this example can effectively isolate the different functional layers of the wavelength conversion device, especially the silver reflective layer, from the air to ensure long-term reliability.

Embodiment 5

In this example, the luminescent layer and the glass bonding layer are integrally replaced with a luminescent glass layer, and the silver bonding layer and the soldering layer are entirely replaced with a thermal conductive adhesive. The specific structure is as shown in FIG. 5, and includes a light-emitting glass layer 501, a silver reflective layer 503, a heat-insulating substrate 504, a thermal conductive paste 505, and a heat-conductive substrate 507 which are sequentially stacked. Wherein, the glass in the luminescent glass layer is made of silicate lead-free glass; the thermal conductive adhesive needs to select a high temperature resistant thermal conductive adhesive, wherein the thermally conductive filler is preferably silver powder.

The specific process is as follows:

Step A: coating silver paste on one side of the substrate to be fired, drying at 60 to 150 ° C; then sintering at 500 to 1000 ° C; forming a silver reflective layer on one side of the alumina substrate and vacant on the other side. The setter substrate selected in this example is a sapphire substrate with a thickness of 1 mm. The silver paste is a mixed slurry of silver powder and an organic carrier. Further, this example was allowed to stand for a while after coating the silver paste.

Step B: coating a mixed slurry of the second glass and the phosphor on the silver reflective layer; then sintering at a high temperature.

Wherein, the organic slurry is further included in the mixed slurry of the second glass and the phosphor. The high temperature sintering temperature is 500 to 1000 °C. It should be noted that the sintering temperature of the luminescent glass layer needs to be controlled so as not to cause the silver reflective layer to be broken; specifically, the sintering temperature is controlled according to the composition of the second glass. In this case, lead-free silicate glass was selected.

Step C: coating a thermal conductive adhesive on the other side of the substrate, and then bonding the thermal conductive substrate to the thermally conductive substrate to obtain a wavelength conversion device. In this example, the heat-conductive substrate is selected from a copper substrate, and the surface thereof is plated with a nickel-gold protective layer.

The wavelength conversion device produced in this example employs a light-emitting glass as a light-emitting layer, and incorporates some of the functional layers as compared with the first embodiment.

Embodiment 6

In this example, the first surface of the light-emitting layer of the wavelength conversion device obtained in the first embodiment is provided with an anti-reflection film or surface roughening on the first surface of the light-emitting layer. The first surface of the light-emitting layer is one surface of the light-emitting layer away from the heat-dissipating substrate; at the same time, the first surface of the light-emitting layer is also the incident and exit surface of the light of the wavelength conversion device. Providing an anti-reflection film or roughening the surface can improve the light efficiency of the wavelength conversion device.

The specific implementation process is based on the first embodiment, and the selection of the light-emitting layer in step B may also be:

One side of the light-emitting layer is subjected to surface roughening treatment, and the other surface which is not roughened is in contact with the second glass paste and is bonded to the silver reflective layer.

For the rest, please refer to the first embodiment.

The surface roughening of the surface of the light-emitting layer in this example can improve the light efficiency of the wavelength conversion device.

Comparative example one

A diffuse reflection slurry formed by mixing diffuse reflection particles, glass powder and organic carrier is coated on one side of the aluminum nitride substrate, and then YAG:Ce ³⁺ ceramic is placed on the diffuse reflection slurry layer and baked at 60 to 150 ° C. Dry; then, 500-1000 ° C high-temperature sintering to form a diffuse reflection layer bonding YAG: Ce ^{3 +} ceramic and aluminum nitride substrate wavelength conversion device. That is, the wavelength conversion device includes a light-emitting layer, a diffuse reflection layer, and an aluminum nitride substrate which are sequentially stacked.

Table 1 Example 1 and Comparative Example 1 Luminous flux under different optical power blue laser excitation conditions

The light flux of the wavelength conversion device of Example 1 and Comparative Example 1 shown in Table 1 above is a curve of the light power of the blue laser light. When the blue light power is 7 W, the luminous flux of the wavelength conversion device of the two is close, as the power of the blue laser power is Increasing to 11.6W, the luminous flux of the comparative-wavelength conversion device reaches 4744.0lm, reaching the maximum value, and when the blue laser power is further increased to 14W, the wavelength conversion device cannot withstand the laser excitation of the power, and the luminous flux is decreased, and this embodiment The wavelength conversion device of the first wavelength conversion device has a linear increase trend under the excitation of 18.6W laser; it shows that the wavelength conversion device of the metal reflective layer of the invention is more efficient under the high power laser excitation than the current diffuse reflection wavelength conversion device. , the brightness is higher.

The other embodiments have similar illuminating characteristics as those of the first embodiment, and the performance thereof is similar to that of the wavelength conversion device in the first embodiment, and details are not described herein again.

The technical features of the above embodiments may be arbitrarily combined. In order to make the description concise, all the combinations are not described in detail. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope of the present specification.

The above content is a further detailed description of the present application in conjunction with the specific embodiments, and the specific implementation of the present application is not limited to the description. It will be apparent to those skilled in the art that the present invention can be made in the form of the present invention without departing from the scope of the present invention.

Claims

A wavelength conversion device, comprising: a light emitting layer, a glass bonding layer, a silver reflecting layer, a bearing substrate, a silver bonding layer, a soldering layer and a heat conducting substrate;

Wherein, the luminescent layer is an inorganic luminescent layer capable of absorbing light of a certain wavelength range and emitting light of different wavelength ranges.
A wavelength conversion device, comprising: a light-emitting layer, a silver reflective layer, a substrate for burning, an adhesive layer and a heat-conducting substrate;

Wherein, the luminescent layer is an inorganic luminescent layer capable of absorbing light of a certain wavelength range and emitting light of different wavelength ranges; the bonding layer is a silver bonding layer or a thermal conductive adhesive.
The wavelength conversion device according to claim 1, wherein the glass bonding layer is a transparent second glass; and the second glass is glass which does not cause a color change reaction with the Ag element.
The wavelength conversion device according to claim 1 or 2, wherein the silver reflective layer and/or the silver bonding layer is a pure silver layer or a composite silver layer containing silver and a third glass.
The wavelength conversion device according to claim 1, wherein said glass bonding layer completely covers a reflecting surface and a side surface of said silver reflecting layer.
The wavelength conversion device according to claim 1, wherein the solder layer is a solder layer or a sintered silver layer.
The wavelength conversion device according to claim 1 or 2, characterized in that the periphery of the side of the wavelength conversion device is at least partially covered with a sealing layer.
The wavelength conversion device according to claim 1, wherein the heat conductive substrate is a metal substrate or a ceramic substrate.
The wavelength conversion device according to claim 1 or 2, wherein the area of the heat conductive substrate is not smaller than the area of the remaining layers.
A light source comprising an excitation light source, characterized by further comprising the wavelength conversion device of any of claims 1-9.