CN112038463A - Ultraviolet LED device and preparation method thereof - Google Patents

Abstract

The invention provides an ultraviolet LED device and a preparation method thereof, wherein the ultraviolet LED device comprises the following components: the ultraviolet LED device comprises an LED support, an LED chip arranged on the LED support and a packaging layer covering the LED chip on the LED support, wherein: the LED support comprises a support body and a cavity arranged on the periphery of the support body, and the LED chip is coated on the support body by the packaging layer based on the cavity; the encapsulation layer includes a protective layer and a reflective layer. By implementing the embodiment of the invention, the nano particles are mixed in the colloid to form the packaging layer, so that the ultraviolet light can be prevented from being absorbed in the light emitting process, and meanwhile, the light emitting efficiency of the ultraviolet light is improved based on the scattering effect and the reflection effect of the nano particles.

Description

A kind of ultraviolet LED device and preparation method thereof

technical field

The invention relates to the technical field of LEDs, in particular to an ultraviolet LED device and a preparation method thereof.

Background technique

Ultraviolet light is widely used in curing, photocatalyst, nail art, mosquito attracting and other fields. Ultraviolet LED devices have the advantages of low energy consumption and long life, and are gradually replacing traditional mercury lamps. However, as the wavelength of UV LED decreases, its luminous efficiency will become lower and lower, and the reduced luminous efficiency indicates that more input is converted into heat energy, which has an important impact on its practical application. At present, epitaxy or on-chip design is the core method to improve the light efficiency of ultraviolet LEDs, but the technical difficulty of epitaxy or on-chip design is difficult, and it is difficult to solve temporarily. The low luminous efficiency is due to the internal absorption of ultraviolet light, which leads to the increase of heat inside the ultraviolet LED device. At present, it can only be solved by increasing heat dissipation on the basis of existing applications or setting a reflective layer on the surface of the LED bracket. This method will improve the ultraviolet Cost of LED devices.

SUMMARY OF THE INVENTION

In order to overcome the defects of low heat dissipation performance and high cost of existing ultraviolet LED devices, the embodiments of the present invention provide an ultraviolet LED device and a preparation method thereof. The encapsulation layer is formed by mixing nanoparticles in a colloid, which can ensure the protection against ultraviolet light. It will not be absorbed in the process of light extraction, and at the same time, the efficiency of ultraviolet light extraction is improved based on the scattering and reflection effects of nanoparticles.

Correspondingly, the present invention provides an ultraviolet LED device, the ultraviolet LED device includes an LED bracket, an LED chip arranged on the LED bracket, and an encapsulation layer covering the LED chip on the LED bracket, wherein: the LED The bracket includes a bracket body and a cavity provided on the periphery of the bracket body, the packaging layer wraps the LED chip on the bracket body based on the cavity; the packaging layer includes a protection layer and a reflection layer, the protection layer The layer is formed by mixing encapsulation glue and nanoparticles, the reflective layer is formed by mixing encapsulation glue and nanoparticles, the reflective layer is located on the LED bracket and around the LED chip, and the protective layer is located on the reflective layer and covered on the LED chip; the mass ratio of the nanoparticles in the reflective layer is greater than the mass ratio of the nanoparticles in the protective layer, and the forbidden band width of the nanoparticles is greater than 5.0eV.

The nanoparticles are boron nitride, or aluminum nitride, or zirconia.

The nanoparticle in the protective layer accounts for 0% to 1% of the total mass of the protective layer; the nanoparticle in the reflective layer accounts for 90% to 99% of the total mass of the reflective layer.

The reflective layer and the protective layer also include a transition layer formed by precipitation of mixed glue mixed with nanoparticles, and the nanoparticles are in the mixed glue from the bottom of the reflective layer to the surface of the transition layer. concentration gradually decreased.

The height of the reflective layer and the transition layer on the bracket body is not higher than the height of the LED chip after the LED chip is fixed on the bracket body.

The particle size of the nanoparticles is between 100 nm and 10 μm.

The ultraviolet LED device further includes a quartz glass, and the quartz glass seals the encapsulation layer based on the cavity.

Correspondingly, the present invention also provides a preparation method of an ultraviolet LED device, the preparation method comprising:

The first encapsulation glue mixed with nanoparticles is cured and formed on the surface of the LED chip to form a first protective layer, the first protective layer covers the LED chip, and the nanoparticles account for the total mass ratio of the first encapsulation glue is between 0% and 1%, and LED chips are provided on the bracket body of the LED bracket with the cavity;

adding a second encapsulation glue mixed with nanoparticles into the cavity, the nanoparticles accounting for between 1% and 20% of the total mass of the second encapsulation glue, and forming a reflective layer on the surface of the support body based on a precipitation method;

After the reflective layer is deposited and formed, the entire cavity is filled with a third packaging glue mixed with nanoparticles, and the nanoparticle accounts for a total mass ratio of the third packaging glue between 0% and 1%, based on the The third packaging glue forms a second protective layer in the cavity;

curing and molding the device after filling the second protective layer to form an ultraviolet LED device;

The forbidden band width of the nanoparticles is greater than 5.0 eV.

The height of the second packaging glue in the cavity is not higher than the height of the LED chip after the LED chip is fixed on the bracket body.

The precipitation method includes a centrifugal precipitation method or a natural precipitation method.

The particle size of the nanoparticles is between 100 nm and 10 μm.

The nanoparticles are made of boron nitride, aluminum nitride, or zirconia.

The method also includes:

After the UV LED device is cured and formed, quartz glass is arranged on the UV LED device.

The ultraviolet LED device provided by the embodiment of the present invention adopts nanoparticles with a high forbidden band width and a glue forming encapsulation layer. When the ultraviolet LED device is working, these nanoparticles do not absorb ultraviolet light, and have a good reflection effect. A good reflective layer is formed at the bottom of the ultraviolet LED device, which can reduce the absorption of ultraviolet light by the surface of the bracket body. When high-refractive-index nanoparticles are doped into the glue to form the encapsulation layer, the nanoparticles can increase the refractive index of the encapsulation layer, reduce the refractive index difference between the encapsulation layer and the chip, and increase the escape cone angle of the chip surface, making more The ultraviolet light escapes; due to the difference in refractive index between the nanoparticles and the encapsulation layer, the ultraviolet light will be scattered on the surface of the nanoparticles, so that the light will change its propagation direction, and more light will be emitted into the air to improve the light extraction efficiency. The mixed nanoparticles have high thermal conductivity, and doping in the colloid can improve the thermal conductivity of the colloid.

In the preparation method of the ultraviolet LED device provided by the embodiment of the present invention, the ultraviolet LED device is formed by mixing nanoparticles with glue, and the manufacturing process is simple. Compared with the existing spraying, arc plating and other methods, the reflective layer is formed on the substrate. , reducing the complexity of the process, the entire reflective layer forming process can be completed only by mixing the material and curing with the device, and it can be achieved without the help of complex process equipment and process environment requirements, and it does not require process control application conditions. High, can reduce auxiliary equipment investment.

Description of drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.

FIG. 1 shows a schematic structural diagram of a first embodiment of an ultraviolet LED device according to an embodiment of the present invention;

FIG. 2 shows a flowchart of a first embodiment of a method for manufacturing an ultraviolet LED device according to an embodiment of the present invention;

FIG. 3 shows a schematic structural diagram of an ultraviolet LED device without a first protective layer formed according to an embodiment of the present invention;

4 shows a schematic structural diagram of an ultraviolet LED device molded with a first protective layer according to an embodiment of the present invention;

5 shows a schematic structural diagram of an ultraviolet LED device after adding a second packaging glue according to an embodiment of the present invention;

FIG. 6 shows a schematic structural diagram of an ultraviolet LED device with a reflective layer realized by depositing an embodiment of the present invention;

FIG. 7 shows a schematic structural diagram of an ultraviolet LED device after adding a third packaging glue according to an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

1 shows a schematic structural diagram of a first embodiment of an ultraviolet LED device in an embodiment of the present invention, the ultraviolet LED device includes an LED bracket (102), an LED chip (104), and a package wrapping the LED chip on the LED bracket layer, wherein: the LED bracket includes a bracket body (105) and a cavity (101) arranged on the periphery of the bracket body, the cavity (101) and the bracket body (105) form a place where the LED chip (104) and the packaging layer can be placed In the accommodation space, the encapsulation layer can wrap the LED chip (104) on the LED support body (105) based on the cavity (101).

Specifically, the encapsulation layer includes a protective layer (106) and a reflective layer (103), the protective layer (106) is formed by mixing encapsulation glue and nanoparticles, the reflective layer (103) is formed by mixing encapsulation glue and nanoparticles, the The reflective layer (103) is located on the surface of the bracket body (105) and is located around the LED chip (104), the protective layer (106) is located on the reflective layer (103) and covers the LED chip (104); the reflective layer (104) The mass ratio of the nanoparticles in 103) is greater than the mass ratio of the nanoparticles in the protective layer (106), and the forbidden band width of the nanoparticles is greater than 5.0 eV.

The nanoparticles here are boron nitride, or aluminum nitride, or zirconia. For example, boron nitride can be selected for the nanoparticles, and the nanoparticles formed based on boron nitride are mixed with the encapsulation glue. The mixed glue acts on the LED bracket. In the cavity, the ultraviolet LED device in the embodiment of the present invention is then cured and formed. These nanoparticles with high forbidden band width will not absorb ultraviolet light, and the reflective layer (103) at the bottom can have a good reflection function, reducing the absorption of ultraviolet light at the bottom of the stent body (105); the protective layer (106) adopts Nanoparticles can achieve scattering effect and increase light extraction effect. When high-refractive-index nanoparticles are doped into the glue to form the encapsulation layer, the nanoparticles can increase the refractive index of the encapsulation layer, reduce the refractive index difference between the encapsulation layer and the chip, and increase the escape cone angle on the chip surface, making more The ultraviolet light escapes; due to the difference in refractive index between the nanoparticles and the encapsulation layer, the ultraviolet light will be scattered on the surface of the nanoparticles, so that the light will change its propagation direction, and more light will be emitted into the air to improve the light extraction efficiency. The mixed nanoparticles have high thermal conductivity, and doping in the colloid can improve the thermal conductivity of the colloid. The use of nanoparticles in the protective layer can improve the light extraction rate and the heat dissipation effect compared with the case of no nanoparticle molding. This is because the protective layer in the prior art has the effect of absorbing ultraviolet light, which will reduce the light extraction rate. , which also makes the internal heat generation and accumulation not easy to conduct out.

In the specific implementation process, the nanoparticle in the protective layer (106) accounts for between 0% and 1% of the total mass of the protective layer. When the mixed glue is mixed, the nanoparticles can be configured to only account for 0.1% of the total mass of the mixed glue. It can also be configured with nanoparticles that only account for 0.2% of the total mass of the mixed glue, or it can be configured with nanoparticles that only account for 0.5% of the total mass of the mixed glue. % to form; the nanoparticles in the reflective layer (103) account for between 90% and 99% of the total mass of the reflective layer, where the reflective layer (103) is formed based on centrifugal precipitation or natural precipitation after the encapsulation glue and nanoparticles are mixed .

In the specific implementation process, the UV LED device based on precipitation molding has a transition layer (1063), and the transition layer (1063) can be regarded as a part of the protective layer (106), which has the same function and function as the protective layer. Nanoparticles account for 1% to 20% of the total mass of the mixed glue. When the mixed glue is proportioned, the nanoparticles can be configured to only account for 1% of the total mass of the mixed glue to form, or the nanoparticles can be configured to only account for the total mass of the mixed glue. 2% of the total mass of the mixed glue can be configured for molding, or only 5% of the total mass of the mixed glue can be configured for molding, or only 10% of the total mass of the mixed glue can be configured to form, or the nanoparticles can only be configured to account for the total mass of the mixed glue. 15% of the total mass of the mixed glue can also be configured to form only 20% of the total mass of the mixed glue. The reflective layer (103) and the transition layer (1063) based on precipitation molding have a concentration of nanoparticles in the mixed glue that gradually decreases from the bottom of the reflective layer (103) to the surface of the transition layer (1063), that is, the reflective layer (103) The concentration at the bottom can reach 99% of the total mass of the mixed glue, the concentration in the middle of the reflective layer (103) can reach 95% of the total mass of the mixed glue, and the concentration on the surface of the reflective layer (103) can reach 95% of the total mass of the mixed glue 90%, the concentration at the bottom of the transition layer (1063) can reach 10% of the total mass of the mixed glue, and the concentration in the middle of the transition layer (1063) can reach 0.8% of the total mass of the mixed glue, at the transition layer (1063) The concentration of the surface can reach 0.05% of the total mass of the mixed glue and so on. Here, the height of the reflective layer (103) and the transition layer (1063) on the bracket body is not higher than the height of the LED chip after the LED chip (104) is fixed on the bracket body, that is, the height of the mixed glue before precipitation is preferably not higher than passing through the surface of the LED chip (104) to avoid precipitation of nanoparticles on the surface of the LED chip (104) and causing light interference.

In the specific implementation process, the particle size of the nanoparticles is controlled between 100nm-10μm, and the nanoparticles in the reflective layer (103) formed at the bottom need to be arranged more densely, which has a better effect on the reflection of ultraviolet light, and the nanoparticles If it is too small, the particles will be too light and easily float in the mixed colloid and cannot settle at the bottom, thus affecting the reflection. If the nanoparticles are too large, the particles will not be dense enough or there will be gaps between the particles, which will affect the reflection at the bottom.

In a specific implementation process, the ultraviolet LED device further includes a quartz glass (107), the quartz glass (107) seals the encapsulation layer based on the cavity (101), and the quartz glass (107) can realize the encapsulation layer on the entire ultraviolet LED device. And the protection of the LED chip, play dust protection and other functions.

In the specific implementation process, through experiments on the relationship between the different mass ratios occupied by nanoparticles of the same size in the protective layer (106) and the light output, the comparison relationship results as shown in Table 1 are obtained:

Table I

From the whole experimental data, it can be seen that when the mass proportion of nanoparticles is between 0 and 1%, the light extraction rate can be improved, and a mixed colloid with a mass proportion of nanoparticles of about 0.4% can be selected for a better light extraction rate.

In the specific implementation process, the relationship between the particle size of the involved nanoparticles and the light output was tested, and the comparison results as shown in Table 2 were obtained:

Table II

From the whole experimental data, it can be seen that the particle size of nanoparticles has little difference in light emission within 100nm-10μm, and the light emission percentage fluctuates around 115%. For a reflective layer, the larger the gap, the less reflection. For the filled mixed glue, the larger the particles, the more obvious the light blocking effect.

Embodiment 2

Fig. 2 shows the flow chart of the first embodiment of the method for preparing the ultraviolet LED device in the embodiment of the present invention, and the specific steps are as follows:

S201. A first protective layer based on the first encapsulation glue mixed with nanoparticles is cured and formed on the surface of the LED chip, the first protective layer covers the LED chip, and the nanoparticles account for the total amount of the first encapsulation glue The mass ratio is between 0% and 1%, and the LED chip is provided on the bracket body of the LED bracket with the cavity;

Figures 3 to 4 show the evolution of the structure of the ultraviolet LED device in which the first protective layer is cured and formed on the LED bracket provided with the LED chip. First, the bracket body ( 105) An LED chip (104) is arranged on the surface, and a high viscosity glue is used on the surface of the LED chip (104) to form a first protective layer (1061). The high viscosity glue is doped with nanoparticles of boron nitride (also aluminum nitride or zirconia), and the nanoparticles account for between 0% and 1% of the total mass. 1061) for curing.

S202, adding a second encapsulation glue mixed with nanoparticles into the cavity, the nanoparticles accounting for between 1% and 20% of the total mass of the second encapsulation glue, and forming a reflective layer on the surface of the support body based on a precipitation method ;

Figures 5 and 6 show the evolution of the structure state of the LED device after curing and molding by adding the second encapsulation glue to the precipitation-molded UV LED device with a reflective structure; in the cavity of the LED device with the first protective layer (1061) In (101), the second encapsulation glue mixed with boron nitride (also aluminum nitride or zirconium oxide) nanoparticles is continued to be added, and the second encapsulation glue is used to form a second glue layer (1062) before centrifugation. The nanoparticles in the encapsulation glue account for 1%-20% of the total mass, and the height of the second glue layer (1062) cannot be higher than the sum of the heights of the LED chip (104) and the first protective layer (1061), Then the second glue layer (1062) in the LED device is precipitated, such as natural precipitation or centrifugal precipitation, so that the nanoparticles can be completely precipitated at the bottom of the support or can be completely covered at the bottom of the support to form boron nitride (or aluminum nitride). or zirconia) nanoparticles are covered on the entire bottom except the LED chip, that is, the reflective layer (103) and the transition layer (1063) are formed, and the nanoparticles in the reflective layer (103) account for 90% of the total mass of the reflective layer to 99%.

Preferably, the height of the second glue layer (1062) in the cavity is not higher than the height of the LED chip after the LED chip (104) is fixed on the bracket body. The advantage of this setting is to avoid precipitation of nanoparticles to the surface of the first protective layer (1061), thereby affecting the light extraction efficiency.

S203. After the reflective layer is formed by precipitation, filling the entire cavity with a third encapsulation glue mixed with nanoparticles, where the nanoparticles account for a total mass ratio of the third encapsulation glue between 0% and 1%, based on The third packaging glue forms a second protective layer in the cavity;

FIG. 7 shows a schematic structural diagram of an ultraviolet LED device after adding a third encapsulation glue according to an embodiment of the present invention. Here, in the cavity (101), a mass ratio of nanoparticles to glue with a mass ratio of 0% to 1% can be added again. The third packaging glue is used to fill the entire cavity (101) through the third packaging glue to form a second protective layer (1064).

S204, curing and molding the device after filling the second protective layer to form an ultraviolet LED device;

Based on the structural state shown in FIG. 7, after the entire device is cured and molded, the protective layer of the UV LED device includes a first protective layer (1061) cured and molded based on the first encapsulation glue, and a transition layer (1061) cured and molded based on the second encapsulation glue. 1063), the second protective layer (1064) formed by curing based on the third encapsulation glue, etc., the first protective layer (1061) is completed before the second encapsulation glue is added, and the transition layer (1063) and The second protective layer (1064) cured and formed based on the third encapsulation glue may be cured and formed after the third encapsulation glue is added. During the curing and forming process of the transition layer (1063) and the second protective layer (1064), the transition layer (1063) formed by the second encapsulation glue can also be cured and formed first, and then the third encapsulation glue is added to form the second protective layer (1064) and then the second protective layer (1064) is cured and formed.

Further, in S205, after the ultraviolet LED device is cured and formed, quartz glass is further arranged on the ultraviolet LED device.

After this step is completed, the ultraviolet LED device with the structure shown in FIG. 1 can be fabricated.

It should be noted that the forbidden band width of the above-mentioned nanoparticles is greater than 5.0 eV, the particle size of the nanoparticles is between 100 nm and 10 μm, and the nanoparticles are boron nitride, aluminum nitride, or zirconia.

It can be seen from the above that the preparation method of the ultraviolet LED device provided by the embodiment of the present invention can complete the ultraviolet LED device by mixing the glue ratio three times, controlling the glue pouring at different time nodes and curing the mixed glue after processing. Compared with the existing methods of spraying, arc plating, etc. to form a reflective layer on the substrate, the process complexity is reduced, and the entire reflective layer is formed. The molding process can be completed only by mixing and molding the substances and curing with the device. It can be realized without the help of complex process equipment and process environment requirements. The requirements for process control application conditions are not high, and the investment in auxiliary equipment can be reduced.

The ultraviolet LED device and the preparation method thereof provided by the embodiments of the present invention have been described in detail above. The principles and implementations of the present invention are described with specific examples in this paper. The descriptions of the above embodiments are only used to help understand the present invention. At the same time, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In summary, the content of this specification should not be construed as Limitations of the present invention.

Claims (13)

1. The ultraviolet LED device is characterized by comprising an LED support, an LED chip arranged on the LED support and an encapsulation layer covering the LED chip on the LED support, wherein: the LED support comprises a support body and a cavity arranged on the periphery of the support body, and the LED chip is coated on the support body by the packaging layer based on the cavity; the LED packaging structure comprises an LED support, a packaging layer, a reflecting layer and a packaging layer, wherein the packaging layer comprises a protective layer and the reflecting layer, the protective layer is formed by mixing packaging glue and nano particles, the reflecting layer is positioned on the LED support and around the LED chip, and the protective layer is positioned on the reflecting layer and covers the LED chip; the mass ratio of the nano particles in the reflecting layer is larger than that of the nano particles in the protective layer, and the forbidden bandwidth of the nano particles is larger than 5.0 eV.

2. The ultraviolet LED device of claim 1, wherein the nanoparticles are boron nitride, or aluminum nitride, or zirconium oxide.

3. The ultraviolet LED device of claim 1, wherein the nanoparticles in the protective layer comprise between 0% and 1% of the total mass of the protective layer; the nano particles in the reflecting layer account for 90 to 99 percent of the total mass ratio of the reflecting layer.

4. The uv LED device of claim 3, further comprising a transition layer deposited from a mixed glue mixed with nanoparticles, wherein the concentration of the nanoparticles in the mixed glue decreases from the bottom of the reflective layer to the surface of the transition layer.

5. The ultraviolet LED device of claim 4, wherein the height of the reflective layer and the transition layer above the mount body is no higher than the LED chip height after the LED chip is secured to the mount body.

6. The ultraviolet LED device of claim 1, wherein the nanoparticles have a particle size between 100nm and 10 μ ι η.

7. The ultraviolet LED device of any one of claims 1 to 6, further comprising a quartz glass enclosing the encapsulation layer based on the cavity.

8. A preparation method of an ultraviolet LED device is characterized by comprising the following steps:

the method comprises the following steps of curing and forming a first protective layer on the surface of an LED chip based on first packaging glue mixed with nano particles, wherein the first protective layer covers the LED chip, the nano particles account for 0-1% of the total mass of the first packaging glue, and the LED chip is arranged on a bracket body of an LED bracket with a cavity;

adding second packaging glue mixed with nanoparticles into the cavity, wherein the nanoparticles account for 1-20% of the total mass of the second packaging glue, and forming a reflecting layer on the surface of the bracket body based on a precipitation method;

filling a third packaging glue mixed with nano particles in the whole cavity after the reflective layer is deposited and formed, wherein the nano particles account for 0-1% of the third packaging glue by mass, and forming a second protective layer in the cavity based on the third packaging glue;

curing and molding the device filled with the second protective layer to form an ultraviolet LED device;

the forbidden band width of the nano-particles is more than 5.0 eV.

9. The method for manufacturing an ultraviolet LED device according to claim 8, wherein the height of the second packaging glue in the cavity is not higher than the height of the LED chip after the LED chip is fixed on the support body.

10. The method of making an ultraviolet LED device of claim 8, wherein the precipitation method comprises a centrifugal precipitation method or a natural precipitation method.

11. The method of making an ultraviolet LED device according to claim 8, wherein the nanoparticles have a particle size between 100nm and 10 μ ι η.

12. The method of claim 8, wherein the nanoparticles are boron nitride, aluminum nitride, or zirconium oxide.

13. The method of manufacturing an ultraviolet LED device according to any one of claims 8 to 12, further comprising:

after the ultraviolet LED device is cured and molded, quartz glass is arranged on the ultraviolet LED device.

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