CN212060849U - Wavelength conversion device, light emitting device, and projection device - Google Patents

Abstract

The utility model relates to a wavelength conversion device and adopt this wavelength conversion device's illuminator and projection arrangement. The wavelength conversion device comprises a luminescent ceramic layer, an adhesive layer, a reflecting layer, a heat conducting intermediate layer, a connecting layer and a substrate which are sequentially superposed; the reflecting layer is plated on the upper surface of the heat-conducting intermediate layer, and the lower surface of the luminescent ceramic layer is bonded with the heat-conducting intermediate layer plated with the reflecting layer through the bonding layer; the lower surface of the heat-conducting intermediate layer is connected with the upper surface of the substrate through a connecting layer; at least the upper surface of the heat-conducting intermediate layer is a flat surface with the area equivalent to that of the reflecting layer. The wavelength conversion device has the characteristics of convenience in processing, good heat conductivity, smoothness of a heat conduction channel of the whole device, high lighting effect and the like.

Description

Wavelength conversion device, light emitting device, and projection device

Technical Field

The utility model relates to an illumination and projection technical field especially relate to a wavelength conversion device and adopt this wavelength conversion device's illuminator and projection arrangement.

Background

At present, laser fluorescence conversion type light sources are developed rapidly and are already widely applied to the fields of illumination and projection display. The laser light source is adopted to excite the fluorescent powder to generate visible light, and the LED fluorescent lamp has the advantages of high conversion efficiency, high brightness, small size, strong controllability and the like.

The wavelength conversion device applied to the laser light source has a very harsh working environment under the continuous irradiation of the laser, and the current packaging of the wavelength conversion material cannot withstand the continuous irradiation of the laser. The traditional glass-packaged inorganic luminescent layer is easy to accumulate a large amount of heat and cannot be discharged due to low heat conductivity of glass, so that the temperature of the traditional glass-packaged inorganic luminescent layer is quickly increased to cause thermal quenching.

In order to overcome the above bottleneck, ceramic packaging phosphor powder is produced, but in the prior art, the surface of the prepared luminescent ceramic layer is directly connected with the substrate after being coated with a film, and a new technical problem is also generated: the substrate has a relatively large area, is easy to deform, has an uneven surface, has a poor bonding effect between the coating on the surface of the luminescent ceramic layer and the surface of the substrate, and influences the light reflection; the heat conduction from the luminescent ceramic layer to the substrate is not smooth, and the thermal resistances of the structures and the mutual interfaces are too high, so that the heat cannot be effectively conducted away.

There is a need to develop a wavelength conversion device with efficient heat conduction and dissipation capabilities.

SUMMERY OF THE UTILITY MODEL

Based on the above problems, the present invention is to provide a wavelength conversion device with good thermal conductivity of the light emitting layer and smooth heat conducting channel of the whole device, especially a wavelength conversion device suitable for continuous irradiation of high power laser source.

The utility model discloses still provide the illuminator and the projection arrangement who use above-mentioned wavelength conversion equipment.

In order to achieve the above purpose, the utility model adopts the following technical scheme:

a wavelength conversion device comprises a luminescent ceramic layer, an adhesive layer, a reflecting layer, a heat conducting intermediate layer, a connecting layer and a substrate which are sequentially superposed; the reflecting layer is plated on the upper surface of the heat-conducting intermediate layer, and the lower surface of the luminescent ceramic layer is bonded with the heat-conducting intermediate layer plated with the reflecting layer through the bonding layer; the lower surface of the heat-conducting intermediate layer is connected with the upper surface of the substrate through a connecting layer; at least the upper surface of the heat-conducting intermediate layer is a flat surface with the area equivalent to that of the reflecting layer.

In the technical scheme of the utility model, the luminescent layer is formed by adopting ceramic packaging fluorescent powder, which has higher thermal conductivity, and the heat conducting intermediate layer connecting the luminescent ceramic layer and the heat radiating substrate has higher thermal conductivity, the heat conducting channel is smooth, and the heat of the luminescent ceramic layer can be rapidly and effectively led out; meanwhile, compared with a large-area substrate, the heat-conducting intermediate layer has a small surface area and is not easy to deform, and a reflecting layer or other functional layers are plated on the surface of the heat-conducting intermediate layer to ensure that a plating layer is smooth; therefore, the wavelength conversion device can bear continuous irradiation of high-power laser and can obtain high light efficiency.

Preferably, the heat conducting intermediate layer is a metal aluminum layer or a ceramic layer, and the ceramic layer can be selected from ceramic layers such as silicon carbide, sapphire and aluminum nitride.

Preferably, the reflecting layer is a silver film reflecting layer, and the silver film reflecting layer has the characteristics of compactness and high reflectivity.

In some embodiments, the high-reflection aluminum with a silver-plated film is selected as the heat-conducting intermediate layer, so that the heat-conducting intermediate layer has high reflectivity; the silver-plated film on the surface of the ceramic is selected as the heat-conducting intermediate layer, so that the ceramic has high strength and hardness and good processing performance, and a flat surface is more easily obtained.

Preferably, a high refractive index dielectric film and a low refractive index dielectric film are sequentially provided on the reflective layer between the adhesive layer and the reflective layer. Specifically, the high refractive index dielectric film and the low refractive index dielectric film may be respectively SiO₂And TiO₂。

Preferably, the adhesive layer is a silica gel adhesive layer, and more preferably, scattering particles can be further added into the silica gel adhesive layer; the scattering particles are added into the silica gel layer, so that the problem that the silica gel thin layer shrinks in the process of solidifying and bonding the luminescent ceramic layer and the reflecting layer can be solved, the reflection can be increased, and the thickness of the silica gel layer can be effectively controlled by adjusting the particle size of the scattering particles.

Preferably, the connecting layer between the heat-conducting intermediate layer and the substrate is an organic high heat-conducting adhesive or a metal welding layer, and more preferably, the metal welding layer is a sintered silver layer.

Preferably, the upper surface of the luminescent ceramic layer is further provided with an antireflection film, specifically an AR antireflection film.

Preferably, the substrate can be selected from substrates with high load bearing capacity and high thermal conductivity, such as metal or ceramic substrates.

The utility model also provides a light-emitting device, which comprises an excitation light source and the wavelength conversion device; the light-emitting ceramic layer of the wavelength conversion device is arranged on a light path of exciting light of the excitation light source and converts the exciting light into exciting light to emit.

The utility model also provides a projection arrangement, including above-mentioned illuminator.

Compared with the prior art, the utility model discloses a wavelength conversion device has following beneficial effect:

the wavelength conversion device of the utility model adopts ceramics as the packaging material of the luminous layer, thus improving the heat conductivity of the luminous layer; the heat conduction intermediate layer is adopted to quickly diffuse and transfer heat generated when the exciting light excites the fluorescent material to generate fluorescence, and the heat conduction intermediate layer is easier to plate a reflecting layer and/or other functional film layers relative to the substrate; a heat dissipation substrate with high heat conductivity is adopted; in addition, the bonding layer between the luminescent ceramic layer and the heat conducting intermediate layer of the plated reflecting layer and the connecting layer between the heat conducting intermediate layer and the substrate also have high heat conductivity. The utility model discloses a wavelength conversion device luminescent layer heat conductivity is good, the luminescent layer is unblocked to the heat conduction channel between the base plate in the whole device, and this wavelength conversion device has excellent heat conduction, heat dispersion, can bear the continuous irradiation of high-power laser and obtain high light efficiency.

Drawings

The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention.

Fig. 1 is a schematic structural diagram of a wavelength conversion device according to a first embodiment of the present invention.

Fig. 2 is a schematic structural diagram of a wavelength conversion device according to a second embodiment of the present invention.

Fig. 3 is a schematic structural diagram of a wavelength conversion device according to a fourth embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, embodiments of the present invention will be further described below with reference to the accompanying drawings.

Referring to fig. 1, the present invention provides a wavelength conversion device 100, which includes a luminescent ceramic layer 101, an adhesive layer 102, a reflective layer 103a, a thermal conductive intermediate layer 103b, a connection layer 104, and a substrate 105, which are sequentially stacked. The reflective layer 103a is plated on the upper surface of the heat conducting intermediate layer 103b in advance, and the lower surface of the luminescent ceramic layer 101 is bonded to the reflective layer 103a through the bonding layer 102; the lower surface of the heat conductive intermediate layer 103b is connected to the upper surface of the substrate 105 through the connection layer 104.

In practical applications of the wavelength conversion device 100, the excitation light incident on the luminescent ceramic layer 101 can excite the fluorescent material to generate fluorescence, thereby realizing wavelength conversion of light.

Wherein, the area of at least the upper surface of the heat conducting intermediate layer 103b is equivalent to the area of the reflecting layer 103a, and the two areas can be equal; the heat conducting intermediate layer 103b is used as a bearing layer of a reflecting layer or other functional layers, and compared with the substrate, the surface area is small, the heat conducting intermediate layer is not easy to deform, and the heat conducting intermediate layer is easier to process and level.

Among them, luminescent ceramic layer 101 may be a common luminescent ceramic in the case of satisfying high thermal conductivity: one is pure phase luminescent ceramic, such as YAG Ce or LuAG Ce ceramic, the ceramic phase and the luminescent phase are in the same phase and can be sintered into ceramic with higher transparency; the other is a complex phase luminescent ceramic, such as Al₂O₃&YAG Ce ceramic or AlN&YAG Ce ceramics, etc. with Al as binder phase₂O₃Or AlN, etc. and the luminescent phase is YAG Ce fluorescent powder. In one embodiment, Al may be used₂O₃The YAG: Ce phosphor is encapsulated to form the luminescent ceramic layer 101. Preferably, the thickness of luminescent ceramic layer 101 is about 50um to 250um in consideration of luminous efficiency and thermal conductivity.

Further, an antireflection film may be disposed on the upper surface of luminescent ceramic layer 101 facing the incident light. The antireflection film can play a role in antireflection, i.e., reducing the reflectivity of the incident excitation light on the upper surface of the luminescent ceramic layer 101, increasing the incidence rate of the excitation light on the luminescent ceramic layer 101, and facilitating the improvement of the light extraction efficiency on the surface of the luminescent ceramic layer 101. In one embodiment, the antireflection film preferably has a thickness of about 0.01um to about 0.1 um.

The heat conductive intermediate layer 103b may be a metal aluminum layer or a ceramic layer having good heat conductivity, and the ceramic layer may be a ceramic layer such as silicon carbide, sapphire, or aluminum nitride. Further, the reflective layer 103a pre-plated on the heat conducting intermediate layer 103b may be a silver film reflective layer 103a, which is pre-plated on the heat conducting intermediate layer 103b by magnetron sputtering or vacuum evaporation, and the prepared silver film reflective layer 103a has high reflectivity, and the preferred thickness of the silver film reflective layer 103a in the present invention is about 0.1 um-20 um. It should be noted that, when using AlN, sapphire, SiC, or other ceramic as the heat conducting intermediate layer 103b, the difference in thermal expansion coefficient between the ceramic heat conducting intermediate layer 103b and the luminescent ceramic layer 101 is small, and it is not easy to cause too large tensile stress due to too large temperature difference change under severe conditions, and will not cause the adhesive layer 102 at the bottom of the luminescent ceramic to tear, and at the same time, the ceramic has high strength and hardness, good processability, and is easier to obtain a flat surface, so the ceramic material is an excellent heat conducting intermediate layer; however, when some ceramic surfaces are plated with the silver film reflective layer 103a, the adhesion is not strong, so some ceramic surfaces need to be plated with a Ni or Cu transition layer before being plated with silver.

Further, a transparent oxide layer, such as Al, may be further coated on the surface of the silver-coated reflective layer 103a₂O₃Or SiO₂And the protective film ensures that the Ag is not easily corroded by water vapor, sulfur compounds and the like in the air. More preferably, the surface of the silver film emitting layer 103a may be coated with alternating layers of high refractive index dielectric film and low refractive index dielectric film, such as SiO₂And TiO₂The thickness is about 10nm to 200 nm; the alternating dielectric film may have 2 or tens of layers, which can protect the Ag filmAnd also acts to increase reflection.

The bonding layer 102 for bonding the luminescent ceramic layer 101 and the heat conductive intermediate layer 103b may be a silicone layer. In some embodiments, when silicone is used as the adhesive layer 102, scattering particles may also be added to the silicone layer, which mainly takes into account: (1) common silica gel has the characteristic of shrinking on a smooth surface, a silica gel thin layer often shrinks when a silica gel layer is cured and bonded, gaps can be formed on a bonding surface due to the shrinkage, the overall performance is greatly threatened, and the shrinkage problem can be improved by adding scattering particles; (2) the scattering particles can assist reflection and adjust the reflection characteristic; (3) because the silica gel layer needs pressure curing bonding, the silica gel layer can be extruded to be extremely thin when the pressure is too high, the bonding force is difficult to ensure, the minimum thickness of the silica gel layer can be determined by selecting the minimum particle size of the added scattering particles, and the thickness of the silica gel layer can be effectively controlled.

After the silica gel containing scattering particles is applied to the upper surface of the heat conductive intermediate layer 103b, the luminescent ceramic layer 101 is bonded to the silica gel, and the two layers are bonded together after pressurization and heat curing by a jig. The addition of scattering particles to the silicone adhesive layer 102 improves the shrinkage and prevents voids from occurring on the adhesive surface, and the scattering particles themselves can also function to increase the reflection, but the addition of excessive scattering particles also weakens the adhesion strength of the adhesive layer, so the addition amount of scattering particles is preferably 5 to 60 wt% in some embodiments. Meanwhile, in order to reduce thermal resistance, the thickness of the silica gel adhesive layer 102 needs to be as small as possible, but too small thickness can cause reduction of bonding firmness, and the minimum thickness of the silica gel layer can be ensured during pressure bonding by adding scattering particles, and experiments show that when the thickness of the silica gel adhesive layer 102 is 0.5-20 microns, the bonding strength can be ensured, and higher light efficiency can be obtained.

Among them, the connecting layer 104 connecting the thermally conductive intermediate layer 103b and the substrate 105 is required to have low thermal resistance and high thermal conductivity. In some embodiments, the connection layer 104 may employ an organic high thermal conductive adhesive; in other embodiments, the connecting layer 104 may be a metal solder layer, such as a solder layer, which is at least one or a combination of gold tin, silver tin, bismuth tin, or lead solder paste, and more preferably, the metal solder layer is a sintered silver layer.

Among them, the substrate 105 may be a metal substrate or a ceramic substrate having high thermal stability and thermal conductivity. Furthermore, the copper substrate with high thermal conductivity, low price and better strength is preferred; when a copper substrate is adopted, after the surface of the copper substrate is polished, an Au layer protective layer can be plated in an evaporation or sputtering mode, so that the surface of the copper substrate is protected from being oxidized and corroded; the thickness of the Au layer protection layer is preferably 0.01um to 0.5 um.

The present application will be described in further detail with reference to specific examples. The following examples are intended to be illustrative of the present application only and should not be construed as limiting the present application.

Example one

As shown in FIG. 1, in the wavelength conversion device 100 of the present embodiment, Al₂O₃The YAG packaging Ce fluorescent powder is a luminescent ceramic layer 101, silica gel is an adhesive layer 102, an aluminum plate of a pre-silvered film reflecting layer 103a is a heat conducting intermediate layer 103b, a sintered silver layer is a connecting layer 104, and a gold-plated copper substrate 105 is a heat conducting substrate. The specific manufacturing method of the wavelength conversion device 100 is as follows:

step A: preparation of luminescent ceramic layer

Mixing Al₂O₃Powder, YAG, Ce phosphor particles, MgO powder assistant and Y₂O₃And after mixing the powder auxiliaries, drying and crushing to obtain powder, putting the powder into a graphite die, sintering the powder into blocks in SPS (spark plasma sintering), and then annealing, cutting, grinding and polishing to obtain the luminescent ceramic layer 101 with the thickness of about 50-250 um.

And B: preparation of heat-conducting intermediate layer

Plating an Ag film on a long and thin aluminum material with the thickness of 0.3 mm-1 mm in an evaporation mode, wherein the Ag film is used as a reflecting layer 103a, and the preferable thickness is about 0.1 um-20 um; more preferably, a transparent protective film, such as Al, may be further deposited thereon₂O₃Or SiO₂So as to ensure that the Ag film is not easy to be corroded by water vapor, sulfur compounds and the like in the air.

Is noteworthy of being longThe coiled aluminum material can be produced in batch by adopting a coiling mode, and is cut into 5 multiplied by 5mm after being coated with a reflecting film²The small-sized aluminum sheet is ready for use as the heat conductive intermediate layer 103b having efficient heat dissipation and heat transfer.

And C: preparation of copper substrate

The copper substrate 105 was processed to have an area of 20X 20mm²The thickness is 3 mm's base plate, and the base plate edge leaves a plurality of screw to with other carrier screw fastenings. After polishing the surface of the copper substrate 105, an Au layer is plated in an evaporation or sputtering manner, wherein the thickness is about 0.01um to 0.5 um.

Step D: bonding of thermally conductive intermediate layer to copper substrate

The silver colloid is prepared by brushing nano silver powder on the copper substrate 105, and the main component of the silver colloid is the nano silver powder and contains a small amount of organic solvent. After the silver colloid is coated, covering the heat-conducting intermediate layer 103b on the silver colloid, pressurizing and compacting by using a jig, and heating at 150-300 ℃ to volatilize the solvent; at this time, the silver nanoparticles are partially melted and bonded to each other to form a bonding layer 104 of a sintered silver layer, thereby bonding the heat conductive intermediate layer 103b and the copper substrate 105. The thermal conductivity of the formed sintered silver layer is 50-200W/(m.k), and the sintered silver layer has excellent thermal conductivity; the thickness of the sintered silver layer is about 2um to 30um, so that the heat-conducting intermediate layer 103b and the copper substrate 105 are tightly connected together.

Step E: bonding of luminescent ceramic layer and heat-conducting intermediate layer

After the aluminum heat-conducting intermediate layer 103B of step B and the copper substrate 105 of step C are soldered by sintering a silver layer, an appropriate amount of silica gel is applied to the central portion of the heat-conducting intermediate layer 103B, and then the luminescent ceramic layer 101 of step a is bonded to the silica gel, pressed by a jig, and heated and cured in an oven at 150 ℃.

Example two

As shown in fig. 2, the wavelength conversion device 200 of the present embodiment is similar to the wavelength conversion device 100 of the first embodiment, and also includes a luminescent ceramic layer 201, a silica gel adhesive layer 202, a silver film reflective layer 203a, an aluminum heat conductive intermediate layer 203b, a sintered silver layer 204, and a gold-plated copper substrate 205. The difference lies in that: the embodiment also comprises an antireflection film 201a arranged on the luminescent ceramic layer 201, and low-refractive-index dielectric films 203a1 and high-refractive-index dielectric films 203a2 which are alternately plated on the silver film reflecting layer 203 a.

Specifically, after the luminescent ceramic layer 201 is prepared in step a, an anti-reflection AR film is plated on the upper surface of the prepared luminescent ceramic layer 201, and the thickness of the anti-reflection AR film is about 0.01um to 0.1um, so as to improve the light extraction efficiency.

In step B, after the silver film reflective layer 203a is plated on the upper surface of the aluminum heat-conducting intermediate layer 203B, the silver film is coated on the surface alternately, wherein the alternate film layers are the high refractive index dielectric film 203a2 and the low refractive index dielectric film 203a1, such as SiO₂And TiO₂The thickness is about 10nm to 200nm, the alternating dielectric film can be 2 layers or tens of layers, in this embodiment, 2 layers are preferred, and the film layer can protect the Ag film and also can play a role in increasing the reflection.

EXAMPLE III

This example is similar to the wavelength conversion device fabricated in the first example. The difference from the first embodiment is that the connection layer connecting the heat conducting intermediate layer and the copper substrate is a solder layer, and the solder layer is specifically selected to be an AuSn solder sheet. Compared with the first embodiment, the different preparation method comprises the following steps:

step D: bonding of thermally conductive intermediate layer to copper substrate

Laying a prefabricated AuSn solder sheet on a copper substrate, wherein the thickness of the prefabricated AuSn solder sheet is 0.1-10 mu m, attaching an aluminum heat-conducting intermediate layer on the solder sheet, pressurizing, and then carrying out heat treatment at the temperature of about 150-300 ℃ so as to weld the heat-conducting intermediate layer and the copper substrate.

Example four

As shown in fig. 3, the wavelength conversion device 300 of the present invention is similar to the wavelength conversion device 100 of the first embodiment, and also includes a luminescent ceramic layer 301, a silica gel adhesive layer 302, a silver film reflective layer 303a, a heat conductive intermediate layer 303b, a sintered silver connection layer 304, and a gold-plated copper substrate 305. The difference from the first embodiment is that the heat conductive intermediate layer 303b is made of ceramic.

Compared with the first embodiment, when ceramic, such as AlN, SiC, or sapphire, is used as the heat conducting intermediate layer 303b instead of aluminum, because the difference between the thermal expansion coefficients of the ceramic and the luminescent ceramic layer 301 is small, the tensile stress is not too large due to too large temperature difference change under severe conditions, the adhesive at the bottom of the luminescent ceramic layer 301 is not torn, and meanwhile, the ceramic has high strength and hardness and good processability, and a flat surface is more easily obtained, so the ceramic heat conducting intermediate layer 303b is a good heat conducting transition layer.

However, the phenomenon of weak adhesion often occurs when the reflective layer 303a is plated with silver on the ceramic heat conducting intermediate layer 303b, and then a plated Ni or Cu film 303a1 is plated on the ceramic surface first, and then the reflective layer 303a is plated with silver. Meanwhile, when the lower surface of the ceramic heat-conducting intermediate layer 303b is bonded with the copper substrate 305 by using sintered silver, the wettability of some ceramics and the sintered silver is not high, and a copper plating layer 304a needs to be plated on the lower surface of the ceramics, and then the ceramics and the copper substrate 305 are welded by using the sintered silver.

Depending on the ceramic material, the Ni or Cu plating layer 303a1 and the Cu plating layer 304a may be present at the same time or only one of them may be present; for example, if AlN ceramic is used as the heat conductive intermediate layer 303b, AlN may directly infiltrate the sintered silver connection layer 304, and thus the layer 304a is not required.

Another aspect of the present invention further provides a light emitting device, which includes an excitation light source and the wavelength conversion device in the above embodiment. The light-emitting device can be applied to projection, illumination and display systems, such as a Liquid Crystal Display (LCD) or a digital light path processor projector (DLP), can also be applied to the technical field of 3D display, and can also be applied to the illumination fields of car lamps, searchlights, stage lamps and the like.

The above is only the embodiment of the present invention, not the limitation of the patent scope of the present invention, all the equivalent structures or equivalent processes of the present invention are utilized, or directly or indirectly applied to other related technical fields, and the same principle is included in the patent protection scope of the present invention.

Claims (10)

1. A wavelength conversion device is characterized by comprising a luminescent ceramic layer, an adhesive layer, a reflecting layer, a heat conducting intermediate layer, a connecting layer and a substrate which are sequentially stacked;

the reflecting layer is plated on the upper surface of the heat-conducting intermediate layer, and the lower surface of the luminescent ceramic layer is bonded with the heat-conducting intermediate layer plated with the reflecting layer through the bonding layer;

the lower surface of the heat-conducting intermediate layer is connected with the upper surface of the substrate through a connecting layer;

at least the upper surface of the heat-conducting intermediate layer is a flat surface with the area equivalent to that of the reflecting layer.

2. The wavelength conversion device according to claim 1, wherein the thermally conductive intermediate layer is a metallic aluminum layer or a ceramic layer.

3. A wavelength conversion device as claimed in claim 2 wherein said reflective layer is a silver film reflective layer.

4. A wavelength conversion device as claimed in any one of claims 1 to 3, wherein a high refractive index dielectric film and a low refractive index dielectric film are provided in this order on said reflective layer between said adhesive layer and said reflective layer.

5. A wavelength conversion device as claimed in any one of claims 1 to 3 wherein said adhesive layer is a silicone adhesive layer.

6. The wavelength conversion device as claimed in claim 5, wherein the silicone adhesive layer further comprises scattering particles.

7. A wavelength conversion device according to any one of claims 1 to 3, wherein the bonding layer between the heat conducting intermediate layer and the substrate is an organic highly heat conducting adhesive or a metal solder layer, and the metal solder layer is a solder layer or a sintered silver layer.

8. A wavelength conversion device as claimed in any one of claims 1 to 3, wherein the luminescent ceramic layer is further provided with an antireflection film on its upper surface.

9. A light emitting device comprising an excitation light source and the wavelength conversion device according to any one of claims 1 to 8.

10. A projection device comprising the light-emitting device according to claim 9.

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