Wavelength conversion device and preparation method therefor, and light-emitting apparatus

Abstract

Provided in the embodiments of the present application is a wavelength conversion device, comprising a substrate, a reflective layer and a wavelength conversion layer. The reflective layer is arranged on a surface of the substrate, and the wavelength conversion layer is arranged on a surface of a sintered silver layer away from the substrate, wherein the reflective layer is the sintered silver layer. Silver paste is respectively coated onto the substrate and the wavelength conversion layer, and the surface of the substrate coated with the silver paste and the surface of the wavelength conversion layer coated with the silver paste are attached and then sintered to form the reflective layer. This formation method eliminates the need for an adhesive on the one hand, thus reducing the number of stacked layers; on the other hand, the bonding between the substrate and the wavelength conversion layer becomes more stable and less prone to delamination. In addition, the embodiments of the present application also provide a fabrication method for the wavelength conversion device, as well as a light-emitting apparatus.

Description

Wavelength conversion device, its fabrication method, and light-emitting device Technical Field

[0001] This application relates to the field of light source technology, specifically to a wavelength conversion device, its preparation method, and a light-emitting device. Background Technology

[0002] Currently, laser-fluorescent conversion light sources are widely used in LED lighting, stage lighting, vehicle lighting, searchlights, and other equipment, offering advantages such as high brightness and high-temperature stability. Among these, the wavelength conversion device is the core component of the laser-fluorescent conversion light source, and its performance plays a decisive role in the quality of the light source.

[0003] Currently, wavelength conversion devices are typically composed of a substrate layer, an adhesive layer, a reflective layer, and a light-emitting layer stacked sequentially. Wavelength conversion devices fabricated in this way suffer from unstable adhesion and mismatched thermal expansion coefficients between layers. Poor adhesion leads to the light-emitting layer easily detaching from the heat-dissipating substrate. Furthermore, the complex interlayer structure increases the difficulty of matching thermal expansion coefficients. During use, as the ambient temperature changes, the materials between the layers undergo varying degrees of contraction and expansion, ultimately leading to device failure and negatively impacting the reliability and long-term stability of the wavelength conversion device. Summary of the Invention

[0004] The purpose of this application is to provide a wavelength conversion device, a method for preparing the same, and a light-emitting device to improve the above-mentioned problems.

[0005] In a first aspect, embodiments of this application provide a wavelength conversion device, including a substrate, a reflective layer, and a wavelength conversion layer. The reflective layer is disposed on the surface of the substrate and is a sintered silver layer. The wavelength conversion layer is disposed on the surface of the sintered silver layer away from the substrate. The reflective layer is formed by sintering silver paste between the surface of the substrate and the surface of the wavelength conversion layer, and is connected to the substrate and the wavelength conversion layer respectively.

[0006] In one embodiment, the sintered silver layer is a high-temperature sintered silver layer, and the porosity of the high-temperature sintered silver layer is 18%-25%.

[0007] In one embodiment, the sintered silver layer is a low-temperature sintered silver layer with a porosity of 10%-17.5%.

[0008] In one embodiment, the reflective layer further includes microspheres, which are uniformly dispersed within the reflective layer.

[0009] In one embodiment, the diameter of the microspheres is 20μm-50μm. Secondly, embodiments of this application also provide a light-emitting device, including a laser source and the aforementioned wavelength conversion device, wherein the laser source emits excitation light to excite the wavelength conversion device to emit laser light.

[0010] Thirdly, embodiments of this application also provide a method for fabricating a wavelength conversion device, comprising:

[0011] The system provides a substrate, a wavelength conversion layer, and silver paste, the silver paste comprising silver particles and an organic carrier;

[0012] The substrate is coated with silver paste on one side of the substrate and then dried, and / or the wavelength conversion layer is coated with silver paste on one side of the substrate and then dried.

[0013] The substrate coated with silver paste and the wavelength conversion layer coated with silver paste are bonded together and then sintered in a sintering furnace to obtain the final product.

[0014] Alternatively, the silver paste-coated surface of the substrate and the wavelength conversion layer are bonded together and then sintered in a sintering furnace to obtain the final product.

[0015] Alternatively, the substrate surface and the silver paste-coated surface of the wavelength conversion layer are bonded together and then sintered in a sintering furnace to obtain the final product.

[0016] In one embodiment, the silver paste further includes microspheres, which constitute 0.1 wt% to 0.5 wt% of the weight of the silver paste.

[0017] In one embodiment, the silver particles include nano-silver particles and micro-silver particles, wherein the micro-silver particles have a particle size of 1μm-4μm, the nano-silver particles have a particle size of 10nm-100nm, and the nano-silver particles account for 1wt%-3wt% of the weight of the silver paste.

[0018] In one embodiment, the silver particles include micron-sized silver particles with a particle size of 1 μm-4 μm.

[0019] In one embodiment, the thickness of the silver paste coated on the surface of the substrate is 10μm-30μm, and the thickness of the silver paste coated on the surface of the wavelength conversion layer is 10μm-20μm.

[0020] The wavelength conversion device and its fabrication method provided in this application involve coating silver paste onto a substrate and a wavelength conversion layer respectively, and then bonding the silver paste-coated surfaces of the substrate and the wavelength conversion layer together and sintering them to form a reflective layer. This method eliminates the need for adhesives, reducing the number of stacked layers, and also ensures a more stable bond between the substrate and the wavelength conversion layer, making it less prone to detachment.

[0021] These or other aspects of this application will become more apparent in the following description of the embodiments. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 is a schematic diagram of the structure of a wavelength conversion device in the prior art as shown in this application.

[0024] Figure 2 is a schematic diagram of a wavelength conversion device provided in Embodiment 1 of this application.

[0025] Figure 3 is a schematic diagram of a wavelength conversion device provided in Embodiment 2 of this application.

[0026] Figure 4 is a schematic diagram of the structure of a light-emitting device provided in an embodiment of this application. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0028] Currently, wavelength conversion devices are typically composed of a substrate layer, an adhesive layer, a reflective layer, and a light-emitting layer stacked sequentially. Wavelength conversion devices fabricated in this way suffer from unstable adhesion and mismatched thermal expansion coefficients between layers. Poor adhesion leads to the light-emitting layer easily detaching from the heat-dissipating substrate. Furthermore, the complex interlayer structure increases the difficulty of matching thermal expansion coefficients. During use, as the ambient temperature changes, the materials between the layers undergo varying degrees of contraction and expansion, ultimately leading to device failure and negatively impacting the reliability and long-term stability of the wavelength conversion device.

[0029] Figure 1 illustrates a prior art wavelength conversion device, which includes, from top to bottom, a phosphor layer 1, a metal reflective layer 2, a protective layer 3, an adhesive layer 4, and a heat dissipation substrate layer 5. The adhesive layer 4 serves to bond the phosphor layer 1 and the heat dissipation substrate layer 5, typically using solder or silver paste. The metal reflective layer 2 is usually fabricated by physical sputtering, and the protective layer 3 is also formed on the surface of the metal reflective layer 2 by metal sputtering to protect it.

[0030] The wavelength conversion device films prepared by this method are diverse, the preparation process is complex, and the equipment requirements are high. The film morphology depends on the roughness of the polished ceramic surface. Due to the presence of voids within the ceramic material, a small number of pits appear on the ceramic surface after polishing. These pits affect the continuity of the sputtered film's surface growth and cannot fully utilize the high reflectivity advantage of the silver reflective film.

[0031] Example 1

[0032] Referring to Figure 2, this embodiment provides a wavelength conversion device 10, including a substrate 100, a reflective layer 200, and a wavelength conversion layer 300. The reflective layer 200 is disposed on one side surface of the substrate 100, and the wavelength conversion layer 300 is disposed on the surface of the reflective layer 200 away from the substrate 100. The reflective layer is formed by sintering silver paste between the surface of the substrate and the surface of the wavelength conversion layer, and is connected to the substrate and the wavelength conversion layer respectively.

[0033] In this embodiment, the substrate 100 is a ceramic substrate 100, such as aluminum nitride, silicon carbide, silicon nitride, alumina, etc. These ceramic substrates 100 have excellent thermal conductivity and high temperature resistance, as well as the advantage of matching the thermal expansion coefficient of fluorescent ceramics. It is understood that in some other embodiments, the substrate 100 may also be a metal substrate 100, and this embodiment does not limit this.

[0034] The wavelength conversion layer 300 is a fluorescent ceramic layer, which can be a single-phase Ce:YAG or Ce:LuAG ceramic, or a multiphase Al2O3-Ce:YAG or Al2O3-Ce:LuAG ceramic. This embodiment does not specifically limit the type of ceramic used. The wavelength conversion layer 300 can convert the excitation light into a laser beam under the excitation of the excitation light. In a more specific embodiment, the laser light can be blue light, and the wavelength conversion layer 300 can convert the blue light into yellow fluorescence.

[0035] The reflective layer 200 can reflect the laser light converted by the wavelength conversion layer 300, and it can also reflect the excitation light. Simultaneously, the reflective layer 200 also serves to tightly connect the substrate 100 and the wavelength conversion layer 300, preventing the wavelength conversion layer 300 from detaching from the substrate 100. Furthermore, the reflective layer 200 can quickly transfer some of the heat overflowing when the excitation light irradiates the wavelength conversion layer 300 to the substrate 100, thereby dissipating the heat. The reflective layer 200 mainly comprises a film layer formed of silver particles, wherein the silver particles can be micron-sized silver particles, i.e., silver particles with a particle size on the micrometer scale.

[0036] The reflective layer 200 is a sintered silver layer, formed by sintering a silver paste. In one embodiment, the reflective layer 200 can be formed by sintering silver paste coated on the surface of the substrate 100 facing the wavelength conversion layer 300 and / or silver paste coated on the surface of the wavelength conversion layer 300 near the substrate 100. Specifically, it can be formed by bonding the silver paste-coated surface of the substrate to the silver paste-coated surface of the wavelength conversion layer and then sintering to form a sintered silver layer; or by bonding the silver paste-coated surface of the substrate to the surface of the wavelength conversion layer and then sintering to form a sintered silver layer; or by bonding the surface of the substrate to the silver paste-coated surface of the wavelength conversion layer and then sintering to form a sintered silver layer. In some embodiments of this application, the sintered silver layer formed after the silver paste is sintered is simultaneously connected to both the substrate and the wavelength conversion layer.

[0037] In some embodiments of this application, the sintered silver layer is a high-temperature sintered silver layer with a porosity of 18%-25%. Since the raw material silver particles for the high-temperature sintered silver layer are micron-sized silver particles with a particle size of 1μm-4μm, after sintering at high temperature (700℃-1000℃ in some embodiments of this application), some micron-sized silver particles will partially melt to form molten silver, connecting adjacent micron-sized silver particles. However, due to the relatively large size of the micron-sized silver particles, it is difficult to completely melt each particle, resulting in adjacent micron-sized silver particles not being completely filled by molten silver. Therefore, the porosity of the high-temperature sintered silver layer formed after high-temperature sintering is 18%-25%. Simultaneously, since some micron-sized silver particles will partially melt after sintering at high temperature, the formed high-temperature sintered silver layer includes micron-sized silver particles with a size of 0.2μm-4μm, and molten silver connecting the micron-sized silver particles.

[0038] The silver paste comprises uniformly mixed silver particles and an organic carrier, which may be selected from one or more of ethyl cellulose, terpineol, butylcarbamate, and butylcarbamate ester. The particle size of the silver particles may be, for example, 1 μm-4 μm. Silver particles within this particle size range are easily dispersed in the organic carrier, thereby forming a dense film after sintering. This is beneficial for improving the reflectivity of the reflective layer 200 and the adhesion between the reflective layer 200 and the substrate 100 and the wavelength conversion layer 300.

[0039] Specifically, the wavelength conversion device 10 described above can be manufactured in the following manner:

[0040] A substrate 100, a wavelength conversion layer 300, and a silver paste are provided. The silver paste comprises silver particles and an organic carrier. During preparation, silver particles with a particle size of 1μm-4μm and the organic carrier are uniformly mixed to form the silver paste. The silver paste is then coated onto one surface of the substrate 100 and / or one surface of the wavelength conversion layer 200 and dried.

[0041] For example, in one embodiment, silver paste is coated on one side surface of the substrate 100. The thickness of the silver paste coating can be, for example, 10μm-30μm. In one embodiment of this application, the thickness is 20μm. After coating, it is dried. The drying can be carried out by natural air drying or by placing the silver paste-coated substrate 100 in an oven, drying chamber, heating table or other equipment. The purpose of drying is to volatilize the excess organic carrier and avoid the formation of voids in the reflective layer 200 due to the volatilization of the organic carrier during the subsequent sintering process. The drying temperature can be 70℃-100℃ and the drying time can be 10min-20min.

[0042] To improve the wettability of the silver paste coating on the substrate 100 and increase the adhesion between the reflective layer 200 formed after subsequent sintering and the substrate 100, the surface of the substrate 100 to be coated with the silver paste can be polished before applying the silver paste. After polishing, the surface of the substrate 100 is smoother, with higher smoothness and gloss, and surface scratches and microcracks are reduced, thus increasing the adhesion between the reflective layer 200 and the substrate 100 after subsequent sintering. Polishing methods can include mechanical polishing, chemical polishing, and electrolytic polishing. Mechanical polishing uses abrasive particles to grind the surface of the substrate 100 to achieve a smooth and glossy effect; chemical polishing uses a chemical solution to react with the surface of the substrate 100 to make the surface smooth; electrolytic polishing uses electrolysis to make the surface smooth, and this embodiment does not limit the method.

[0043] Meanwhile, after coating one side of the wavelength conversion layer 300 with silver paste, it is dried. The thickness of the silver paste coating can be, for example, 10μm-20μm. In one embodiment of this application, the thickness is 15μm. After coating, it is dried. The drying can be carried out by natural air drying or by placing the wavelength conversion layer 300 coated with silver paste into an oven, drying chamber, heating table or other equipment. The purpose of drying is to volatilize the excess organic carrier and avoid the formation of voids in the reflective layer 200 due to the volatilization of the organic carrier during the subsequent sintering process. The drying temperature can be 70℃-100℃.

[0044] Similarly, to improve the wettability of the silver paste coating on the wavelength conversion layer 300 and increase the adhesion between the reflective layer 200 and the wavelength conversion layer 300 after subsequent sintering, the surface of the wavelength conversion layer 300 for silver paste coating can be polished before applying the silver paste. This will increase the adhesion between the reflective layer 200 and the wavelength conversion layer 300 after subsequent sintering. The polishing method can be referred to the above content and will not be repeated here.

[0045] After the silver paste-coated surface of the substrate 100 and the silver paste-coated surface of the wavelength conversion layer 300 are bonded together, they are placed in a sintering furnace for sintering. The sintering furnace can be a muffle furnace, the sintering temperature can be 700℃-950℃, and the sintering time can be 30min-3h. This embodiment does not limit these limitations.

[0046] After sintering, the silver paste forms a reflective layer 200, which is bonded between the substrate 100 and the wavelength conversion layer 300. Since silver paste is pre-coated on the surfaces of the wavelength conversion layer 300 and the substrate 100 and then dried, the silver paste exhibits good wetting between itself and both the wavelength conversion layer 300 and the substrate 100. After sintering, the adhesion between the reflective layer 200 and the substrate 100, and between the reflective layer 200 and the wavelength conversion layer 300, is good, and the wavelength conversion layer 300 is less likely to detach from the substrate 100. Furthermore, the reflective layer 200 prepared by sintering has high reflectivity and strong adhesion, thus eliminating the need for adhesive layers or other film structures. This reduces the manufacturing cost of the wavelength conversion device 10 and also decreases its size.

[0047] In other embodiments, silver paste may be applied only to the substrate 100 or the wavelength conversion layer 200. After the silver paste is applied, the substrate 100 and the wavelength conversion layer 200 are bonded together, with the silver paste positioned between the substrate 100 and the wavelength conversion layer 200. After bonding, sintering is performed. In this case, the coating thickness of the silver paste may be, for example, 20 μm-40 μm. In one embodiment of this application, the thickness is 30 μm.

[0048] The wavelength conversion device 10 provided in this embodiment uses a sintered silver layer formed by sintering as the reflective layer 200. Compared with the prior art, the structure is simpler, the preparation process is simple and convenient and suitable for mass production. It can reasonably control the layer thickness, and the interlayer thermal resistance is small, which is conducive to the rapid heat dissipation.

[0049] Example 2

[0050] Referring to Figure 3, this embodiment provides a wavelength conversion device 10, which differs from Embodiment 1 in that the structure of the reflective layer 200 is different. The following only describes the parts that are different from Embodiment 1. For the parts that are the same, please refer to the relevant content of Embodiment 1, which will not be repeated here.

[0051] In this embodiment, the reflective layer 200 further includes microspheres 210, which are uniformly dispersed within the reflective layer 200, i.e., the microspheres 210 and silver particles are uniformly dispersed. The microspheres 210 can be, for example, at least one of spherical alumina or boron nitride. The diameter of the microspheres 210 can be 20μm-50μm, and in other embodiments of this application, it is 30μm. Compared to silver particles, the diameter of the microspheres 210 is larger, and the microspheres 210 have high thermal conductivity, allowing them to quickly diffuse and transfer heat to the surroundings, which is then dissipated through the substrate 100, improving the heat dissipation effect of the entire wavelength conversion device 10. In this embodiment, the thickness of the reflective layer 200 is the same as the diameter of the microspheres 210. By adding microspheres 210, the thickness of the reflective layer 200 can be precisely controlled. In other embodiments, the thickness of the reflective layer 200 and the diameter of the microspheres 210 may be different.

[0052] In this embodiment, the reflective layer 200 is formed by sintering silver paste coated on the surface of the substrate 100 facing the wavelength conversion layer 300 and silver paste coated on the surface of the wavelength conversion layer 300 near the substrate 100. In other embodiments of this application, the reflective layer 200 is formed by bonding silver paste coated on the surface of the substrate 100 facing the wavelength conversion layer 300 and the surface of the wavelength conversion layer 300 near the substrate 100 and then sintering, or the reflective layer 200 is formed by sintering silver paste coated on the surface of the substrate 100 facing the wavelength conversion layer 300 and the surface of the wavelength conversion layer 300 near the substrate 100. The silver paste includes uniformly mixed silver particles, microspheres 210, and an organic carrier.

[0053] The wavelength conversion device 10 in this embodiment can be fabricated in the following manner:

[0054] A substrate 100, a wavelength conversion layer 300, and silver paste are provided. The silver paste includes silver particles and an organic carrier. During preparation, silver particles with a particle size of 1μm-4μm, microspheres 210, and the organic carrier are uniformly mixed to form the silver paste. If too much microsphere 210 is added, it may reduce the reflectivity of the reflective layer 200. If too little is added, the improvement in heat dissipation is limited. In one embodiment, the amount of microsphere 210 added to the silver paste can be 0.1wt%-0.5wt% of the weight of the silver paste. Within this range, it has almost no effect on the reflectivity of the reflective layer 200, but it significantly improves the heat dissipation effect.

[0055] Then, silver paste is coated on one side of the substrate 100. The thickness of the silver paste coating can be, for example, 20μm-50μm. In one embodiment of this application, the thickness is 30μm. After coating, it is dried. Drying can be carried out by natural air drying or by placing the silver paste-coated substrate 100 in an oven, drying chamber, heating table or other equipment. The purpose of drying is to volatilize the excess organic carrier and avoid the formation of voids in the reflective layer 200 due to the volatilization of the organic carrier during the subsequent sintering process. The drying temperature can be 70℃-100℃ and the drying time can be 10min-20min.

[0056] To improve the wettability of the silver paste applied to the substrate 100 and increase the adhesion between the reflective layer 200 formed after subsequent sintering and the substrate 100, the surface of the substrate 100 to be coated with silver paste can be polished before applying the silver paste. After polishing, the surface of the substrate 100 is smoother, the smoothness and gloss of the substrate 100 are higher, and surface scratches and microcracks can be reduced, thereby increasing the adhesion between the reflective layer 200 and the substrate 100 after subsequent sintering to form the reflective layer 200.

[0057] The wavelength conversion layer 300 is attached to the silver paste-coated surface of the substrate 100. After attachment, it is placed in a sintering furnace for sintering. The sintering furnace can be a muffle furnace, the sintering temperature can be 700℃-1000℃, and the sintering time can be 30min-3h. This embodiment does not limit these limitations.

[0058] After sintering, the sintered silver paste forms a sintered silver layer as a reflective layer 200, which is connected between the substrate 100 and the wavelength conversion layer 300. Since the silver paste is pre-coated on the surface of the substrate 100 and dried, there is good wetting between the silver paste and the substrate 100. After sintering, the adhesion between the reflective layer 200 and the substrate 100 is good, and the wavelength conversion layer 300 is unlikely to detach from the substrate 100. Furthermore, the reflective layer 200 prepared by sintering has high reflectivity and strong adhesion, thus eliminating the need for adhesive layers or other film structures. This reduces the manufacturing cost of the wavelength conversion device 10 and also reduces its size.

[0059] The wavelength conversion device 10 provided in this embodiment uses a sintered silver layer formed by sintering as the reflective layer 200. Compared with the prior art, the structure is simpler, the preparation process is simple and convenient and suitable for mass production. It can reasonably control the layer thickness, and the interlayer thermal resistance is small, which is conducive to the rapid heat dissipation.

[0060] Example 3

[0061] Referring to Figure 2, this embodiment provides a wavelength conversion device 10, which differs from Embodiment 1 in that the substrate 100 is of a different type and the composition of the reflective layer 200 is different. The following only describes the parts that are different from Embodiment 1. For the parts that are the same, please refer to the relevant content of Embodiment 1, which will not be repeated here.

[0062] In this embodiment, the substrate 100 is a metal substrate 100. Compared with the ceramic substrate 100, the metal substrate 100 has superior thermal conductivity and stronger heat dissipation capacity. The metal substrate 100 can be copper, aluminum, tungsten copper substrate 100, etc. However, the metal substrate 100 cannot withstand high-temperature calcination, so the sintering temperature in the subsequent sintering process cannot be too high. Through long-term research, the applicant has discovered that the particle size of silver particles significantly affects their melting point. When the particle size of silver particles reaches the nanometer level, the melting point of silver particles will be significantly reduced, down to about 100°C. Therefore, the low-temperature sintering characteristics of nano-silver can be utilized to reduce the sintering temperature in the subsequent sintering process. At the same time, it will not affect the physical properties of the reflective layer 200 formed after sintering.

[0063] In this embodiment, the reflective layer 200 includes silver particles, which include nano-silver particles and micro-silver particles. The particle size of the nano-silver particles can be 10nm-100nm, and the particle size of the micro-silver particles can be 1μm-4μm. When the particle size of the silver particles reaches the nanometer level, the melting point of the silver particles is significantly reduced, reaching as low as around 100℃. Therefore, in some embodiments of this application, sintering at a temperature of 100℃-500℃ is referred to as low-temperature sintering. In another embodiment of this application, the sintering temperature for low-temperature sintering is 100℃-300℃. During low-temperature sintering, the micro-silver particles, due to their larger size, hardly undergo any melting change, while the nano-silver particles with a particle size of 10nm-100nm will melt to form molten silver, connecting the non-molten micro-silver particles to form a low-temperature sintered silver layer. This connects the substrate and the wavelength conversion layer, resulting in a low-temperature sintered silver layer that includes 1μm-4μm micro-sized silver particles and molten silver connecting the micro-sized silver particles. It should be noted that in this application, molten silver does not refer to silver that flows freely in a molten state, but rather to silver that is fixed in a molten state after micron-sized silver particles are interconnected and do not have a specific shape; it is solid silver. Because nano-silver particles with a particle size of 10nm-100nm have high fluidity when sintered and melted, they can penetrate the voids left by the micron-sized silver particles, resulting in a porosity of 10%-17.5% in the prepared low-temperature sintered silver layer. Compared to high-temperature sintered silver, which is sintered using only micron-sized silver particles, the porosity is lower, resulting in higher adhesion, thermal conductivity, and reflectivity of the low-temperature sintered silver. In other embodiments of this application, the porosity in the low-temperature sintered silver layer is 15%.

[0064] Specifically, the wavelength conversion device 10 in this embodiment can be fabricated in the following manner:

[0065] A substrate 100, a wavelength conversion layer 300, and silver paste are provided. The silver paste includes silver particles and an organic carrier. The silver particles include silver nanoparticles and micron-sized silver particles. During preparation, micron-sized silver particles with a particle size of 1μm-4μm, silver nanoparticles with a particle size of 10nm-100nm, and the organic carrier are uniformly mixed to form the silver paste. Since the manufacturing cost of silver nanoparticles is higher, excessive addition may lead to a higher manufacturing cost for the wavelength conversion device 10. Preferably, in one embodiment, the amount of silver nanoparticles added to the silver paste can be 1wt%-3wt% of the weight of the silver paste, for example, 1wt%, 1.5wt%, 2wt%, 2.5wt%, etc. Within this range, the subsequent sintering temperature is already low, and the increase in manufacturing cost is small.

[0066] Then, silver paste is coated on one side surface of the substrate 100. The thickness of the silver paste coating can be, for example, 10μm-30μm. In one embodiment of this application, the thickness is 20μm. After coating, it is dried. Drying can be carried out by natural air drying or by placing the silver paste-coated substrate 100 in an oven, drying chamber, heating table or other equipment. The purpose of drying is to volatilize the excess organic carrier and avoid the formation of voids in the reflective layer 200 due to the volatilization of the organic carrier during the subsequent sintering process. The drying temperature can be 70℃-100℃ and the drying time can be 10min-20min.

[0067] To improve the wettability of the silver paste applied to the substrate 100 and increase the adhesion between the reflective layer 200 formed after subsequent sintering and the substrate 100, the surface of the substrate 100 to be coated with silver paste can be polished before applying the silver paste. After polishing, the surface of the substrate 100 is smoother, the smoothness and gloss of the substrate 100 are higher, and surface scratches and microcracks can be reduced, thereby increasing the adhesion between the reflective layer 200 and the substrate 100 after subsequent sintering to form the reflective layer 200.

[0068] After coating one side of the wavelength conversion layer 300 with silver paste, it is dried. The thickness of the silver paste coating can be, for example, 10μm-20μm. In one embodiment of this application, the thickness is 15μm. After coating, it is dried. The drying can be carried out by natural air drying or by placing the wavelength conversion layer 300 coated with silver paste in an oven, drying chamber, heating table or other equipment. The purpose of drying is to volatilize the excess organic carrier and avoid the formation of voids in the reflective layer 200 due to the volatilization of the organic carrier during the subsequent sintering process. The drying temperature can be 70℃-100℃.

[0069] Similarly, in order to improve the wettability of the silver paste coating on the wavelength conversion layer 300 and increase the adhesion between the reflective layer 200 and the wavelength conversion layer 300 formed after subsequent sintering, the surface of the wavelength conversion layer 300 for coating the silver paste can be polished before coating the silver paste, so that the adhesion between the reflective layer 200 and the wavelength conversion layer 300 is increased after the reflective layer 200 is formed by subsequent sintering.

[0070] After the silver paste-coated surface of the substrate 100 and the silver paste-coated surface of the wavelength conversion layer 300 are bonded together, they are placed in a sintering furnace for sintering. The sintering furnace can be a muffle furnace, the sintering temperature can be 100℃-500℃, and the sintering time can be 30min-3h. This embodiment does not limit these limitations.

[0071] After sintering, the silver paste forms a reflective layer 200, which is bonded between the substrate 100 and the wavelength conversion layer 300. Since silver paste is pre-coated on the surfaces of the wavelength conversion layer 300 and the substrate 100 and then dried, the silver paste exhibits good wetting between itself and both the wavelength conversion layer 300 and the substrate 100. After sintering, the adhesion between the reflective layer 200 and the substrate 100, and between the reflective layer 200 and the wavelength conversion layer 300, is good, and the wavelength conversion layer 300 is less likely to detach from the substrate 100. Furthermore, the reflective layer 200 prepared by sintering has high reflectivity and strong adhesion, thus eliminating the need for adhesive layers or other film structures. This reduces the manufacturing cost of the wavelength conversion device 10 and also decreases its size.

[0072] The wavelength conversion device 10 provided in this embodiment uses a sintered silver layer formed by sintering as the reflective layer 200. Compared with the prior art, the structure is simpler, the preparation process is simple and convenient and suitable for mass production, the layer thickness can be reasonably controlled, the interlayer thermal resistance is small, which is conducive to the rapid heat dissipation. Moreover, due to the addition of nano-silver particles, the sintering temperature is significantly reduced, and at this sintering temperature, it will not have an adverse effect on the metal substrate 100.

[0073] It is understood that the substrate 100 in this embodiment can also be a ceramic substrate 100, which can also reduce the sintering temperature and thus reduce the sintering cost.

[0074] Example 4

[0075] Referring to Figure 3, this embodiment provides a wavelength conversion device 10, which differs from Embodiment 3 in that the structure of the reflective layer 200 is different. The following only describes the parts that are different from Embodiment 3. For the parts that are the same, please refer to the relevant content of Embodiment 3, which will not be repeated here.

[0076] In this embodiment, the reflective layer 200 further includes microspheres 210, which are uniformly dispersed within the reflective layer 200, i.e., the microspheres 210 and silver particles are uniformly dispersed. The microspheres 210 can be, for example, at least one of spherical alumina or boron nitride. The diameter of the microspheres 210 can be 20μm-50μm; in one embodiment of this application, it is 30μm. Compared to silver particles, the diameter of the microspheres 210 is larger, and the microspheres 210 have high thermal conductivity, allowing them to quickly diffuse and transfer heat to the surroundings, which is then dissipated through the substrate 100, improving the heat dissipation effect of the entire wavelength conversion device 10.

[0077] In this embodiment, the reflective layer 200 is formed by sintering silver paste coated on the surface of the substrate 100 facing the wavelength conversion layer 300. In other embodiments of this application, the reflective layer 200 is formed by bonding silver paste coated on the surface of the substrate 100 facing the wavelength conversion layer 300 to the surface of the wavelength conversion layer 300 near the substrate 100 and then sintering, or the reflective layer 200 is formed by sintering silver paste coated on the surface of the wavelength conversion layer 300 near the substrate 100. The silver paste includes uniformly mixed silver particles, microspheres 210, and an organic carrier.

[0078] The wavelength conversion device 10 in this embodiment can be fabricated in the following manner:

[0079] A substrate 100, a wavelength conversion layer 300, and silver paste are provided. The silver paste includes silver particles, microspheres 210, and an organic carrier. The silver particles include nano-silver particles and micron-silver particles. During preparation, micron-silver particles with a particle size of 1μm-2μm, nano-silver particles with a particle size of 10nm-100nm, microspheres 210, and an organic carrier are uniformly mixed to form the silver paste. If too much microsphere 210 is added, it may reduce the reflectivity of the reflective layer 200. If too little is added, the improvement in heat dissipation is limited. In one embodiment, the amount of microsphere 210 added to the silver paste can be 0.1wt%-0.5wt% of the weight of the silver paste. Within this range, it has almost no effect on the reflectivity of the reflective layer 200, but the improvement in heat dissipation is more significant.

[0080] Then, silver paste is coated on one side of the substrate 100. The thickness of the silver paste coating can be, for example, 20μm-50μm. In one embodiment of this application, the thickness is 30μm. After coating, it is dried. Drying can be carried out by natural air drying or by placing the silver paste-coated substrate 100 in an oven, drying chamber, heating table or other equipment. The purpose of drying is to volatilize the excess organic carrier and avoid the formation of voids in the reflective layer 200 due to the volatilization of the organic carrier during the subsequent sintering process. The drying temperature can be 70℃-100℃ and the drying time can be 10min-20min.

[0081] To improve the wettability of the silver paste applied to the substrate 100 and increase the adhesion between the reflective layer 200 formed after subsequent sintering and the substrate 100, the surface of the substrate 100 to be coated with silver paste can be polished before applying the silver paste. After polishing, the surface of the substrate 100 is smoother, the smoothness and gloss of the substrate 100 are higher, and surface scratches and microcracks can be reduced, thereby increasing the adhesion between the reflective layer 200 and the substrate 100 after subsequent sintering to form the reflective layer 200.

[0082] The wavelength conversion layer 300 is bonded to the silver paste-coated surface of the substrate 100. After bonding, it is placed in a sintering furnace for sintering. The sintering furnace can be a muffle furnace, the sintering temperature can be 100℃-500℃, and the sintering time can be 30min-3h. This embodiment does not limit these limitations.

[0083] After sintering, the silver paste is sintered to form a sintered silver layer as the reflective layer 200, which is connected between the substrate 100 and the wavelength conversion layer 300. Since the silver paste is pre-coated on the surface of the substrate 100 and dried, there is good wetting effect between the silver paste and the substrate 100. After sintering, the adhesion between the reflective layer 200 and the substrate 100 is good, and the wavelength conversion layer 300 is unlikely to detach from the substrate 100. Furthermore, the reflective layer 200 prepared by sintering has high reflectivity and strong adhesion, so there is no need to set up film structures such as adhesive layers, which reduces the manufacturing cost of the wavelength conversion device 10 and also reduces the size of the wavelength conversion device 10.

[0084] The wavelength conversion device 10 provided in this embodiment uses a sintered silver layer formed by sintering as the reflective layer 200. Compared with the prior art, the structure is simpler, the preparation process is simple and convenient and suitable for mass production, the layer thickness can be reasonably controlled, the interlayer thermal resistance is small, which is conducive to the rapid heat dissipation. Moreover, due to the addition of nano-silver particles, the sintering temperature is significantly reduced, and at this sintering temperature, it will not have an adverse effect on the metal substrate 100.

[0085] Meanwhile, referring to Figure 4, this application also provides a light-emitting device 1, including a wavelength conversion device 10. The wavelength conversion device 10 can be any of the wavelength conversion devices 10 provided in the above embodiments. In a more specific embodiment, the light-emitting device 1 may also include an excitation light source 20, which is used to emit excitation light. The excitation light may be, for example, a blue laser. The wavelength conversion layer 300 of the wavelength conversion device 10 is used to receive the excitation light and, under the excitation of the excitation light, convert at least a portion of the excitation light into a laser. The wavelengths of the laser and the excitation light are different. For example, the laser may be yellow light.

[0086] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A wavelength conversion device, characterized in that, include: substrate; A reflective layer is disposed on the surface of the substrate, and the reflective layer is a sintered silver layer; as well as A wavelength conversion layer is disposed on the surface of the sintered silver layer away from the substrate. The reflective layer is formed by sintering silver paste between the surface of the substrate and the surface of the wavelength conversion layer, and is connected to the substrate and the wavelength conversion layer respectively.

2. The wavelength conversion device according to claim 1, characterized in that, The sintered silver layer is a high-temperature sintered silver layer, and the porosity of the high-temperature sintered silver layer is 18%-25%.

3. The wavelength conversion device according to claim 1, characterized in that, The sintered silver layer is a low-temperature sintered silver layer, and the porosity of the low-temperature sintered silver layer is 10%-17.5%.

4. The wavelength conversion device according to any one of claims 1-3, characterized in that, The reflective layer also includes microspheres, which are uniformly dispersed within the reflective layer.

5. The wavelength conversion device according to claim 4, characterized in that, The diameter of the microspheres is 20μm-50μm.

6. A light-emitting device, characterized in that, The light-emitting device includes a laser source and a wavelength conversion device as described in any one of claims 1-5, wherein the laser source emits excitation light to excite the wavelength conversion device to emit laser light.

7. The method for preparing the wavelength conversion device according to any one of claims 1-5, characterized in that, include: A substrate, a wavelength conversion layer, and a silver paste are provided, wherein the silver paste comprises silver particles and an organic carrier; The silver paste is applied to one side of the substrate and then dried, and / or the silver paste is applied to one side of the wavelength conversion layer and then dried; The substrate is obtained by bonding the silver paste-coated surface of the substrate and the silver paste-coated surface of the wavelength conversion layer together and then sintering them in a sintering furnace; or, the substrate is obtained by bonding the silver paste-coated surface of the substrate and the wavelength conversion layer together and then sintering them in a sintering furnace; or, the substrate is obtained by bonding the silver paste-coated surface of the substrate and the wavelength conversion layer together and then sintering them in a sintering furnace.

8. The method for preparing the wavelength conversion device according to claim 7, characterized in that, The silver paste also includes microspheres, which account for 0.1wt%-0.5wt% of the weight of the silver paste.

9. The method for preparing the wavelength conversion device according to claim 7, characterized in that, The silver particles include nano-silver particles and micro-silver particles. The micro-silver particles have a particle size of 1μm-4μm, and the nano-silver particles have a particle size of 10nm-100nm. The nano-silver particles account for 1wt%-3wt% of the weight of the silver particles.

10. The method for preparing the wavelength conversion device according to claim 7, characterized in that, The silver particles include micron-sized silver particles with a particle size of 1μm-4μm.

11. The method for preparing the wavelength conversion device according to claim 7, characterized in that, The thickness of the silver paste coated on the surface of the substrate is 10μm-30μm, and the thickness of the silver paste coated on the surface of the wavelength conversion layer is 10μm-20μm.

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