An ultraviolet LED packaging structure and its packaging method

Abstract

The present invention discloses an ultraviolet LED packaging structure and a packaging method thereof. The ultraviolet LED packaging structure includes a bracket and a transparent cover plate. The bracket has a receiving cavity, and the transparent cover plate seals the receiving cavity. The bracket includes an annular dike, the receiving cavity is arranged within the dike, a first boss is arranged on the end face of the dike, the first boss is connected to the transparent cover plate, the first boss is close to the receiving cavity, a first glue layer is arranged on the side of the end face away from the receiving cavity, and a second glue layer is arranged between the first boss and the first glue layer. By arranging the first boss on the end face of the dike, during assembly, the transparent cover plate can be directly in contact with and connected to the first boss, avoiding the transparent cover plate from shifting. During use, the first boss can block the ultraviolet light of the LED device, preventing the ultraviolet light from entering the first glue layer and the second glue layer, thereby avoiding the cracking phenomenon of the first glue layer and the second glue layer, and ensuring the airtightness of the LED device during use.

Description

Technical Field

[0001] The present invention relates to the technical field of LEDs, and particularly to an ultraviolet LED packaging structure and a packaging method thereof. Background Art

[0002] The method of placing a planar quartz glass or a lens after coating glue on the edge of a cup-shaped ceramic substrate is a mainstream packaging method for current ultraviolet LED products. This packaging method has the following disadvantages:

[0003] 1. The dispensing efficiency of coating glue on the edge of the cup-shaped ceramic substrate is relatively low. The dispensing head needs to run uniformly along the edge of the substrate for one week, and the glue volume is not easy to control, and it is easy to have a situation of too much or too little dispensing volume.

[0004] 2. When the glue volume is large, the glue is easy to overflow and flow into the vicinity of the chip in the cup. Under ultraviolet irradiation, the glue near the chip will crack.

[0005] 3. When the glue volume is small, air bubbles will be formed inside the glue, and in severe cases, an air channel will be formed, seriously affecting the airtightness of the product.

[0006] 4. When bonding the quartz glass or the lens, it is easy to have a situation where the quartz glass or the lens is offset, and manual alignment is required, which takes a long time and wastes manpower and material resources, and the production efficiency is relatively low. Summary of the Invention

[0007] An object of an embodiment of the present invention is to provide an ultraviolet LED packaging structure, which can avoid the cracking of the glue and has good airtightness of the product.

[0008] Another object of an embodiment of the present invention is to provide an ultraviolet LED packaging method, which can improve the production efficiency of LED devices.

[0009] To achieve the above object, the present invention adopts the following technical solutions:

[0010] In a first aspect, there is provided an ultraviolet LED packaging structure, including a bracket and a transparent cover plate. The bracket has a receiving cavity, and the transparent cover plate seals the receiving cavity. The bracket includes an annular dike. The receiving cavity is arranged inside the dike. The end face of the dike is provided with a first boss. The first boss is connected to the transparent cover plate. The first boss is close to the receiving cavity. A first glue layer is arranged on the side of the end face away from the receiving cavity. A second glue layer is arranged between the first boss and the first glue layer.

[0011] As a preferred solution of the ultraviolet LED packaging structure, the first glue layer is at least located below the transparent cover plate.

[0012] As a preferred solution of the ultraviolet LED packaging structure, the first glue layer is located outside the edge of the transparent cover plate.

[0013] As a preferred solution of the ultraviolet LED packaging structure, the hardness of the first glue layer is greater than that of the second glue layer.

[0014] As a preferred solution of the ultraviolet LED packaging structure, the refractive index of the first glue layer is greater than that of the second glue layer.

[0015] As a preferred solution of the ultraviolet LED packaging structure, the first boss and the dam are integrally formed.

[0016] As a preferred solution of the ultraviolet LED packaging structure, it includes a packaging layer, and the packaging layer wraps the outer surface of the transparent cover plate and shields the first glue layer and the second glue layer.

[0017] As a preferred solution of the ultraviolet LED packaging structure, the packaging layer is a fluorocarbon film; and / or,

[0018] The thickness of the packaging layer is greater than 100 nanometers.

[0019] As a preferred solution of the ultraviolet LED packaging structure, a second boss is provided on the end surface, the second boss is spaced on the side of the first boss away from the accommodation cavity, the first glue layer is provided on the second boss, the second glue layer is provided between the second boss and the first boss, and the height of the second boss is lower than the height of the first boss.

[0020] In a second aspect, there is provided an ultraviolet LED packaging method for manufacturing the above-mentioned ultraviolet LED packaging structure, including the following steps:

[0021] Perform a first glue dotting operation on the end surface of the bracket dam to form a first glue layer;

[0022] Perform a second glue dotting operation on the end surface to form a second glue layer;

[0023] Bond and fix the transparent cover plate to the second glue layer.

[0024] As a preferred solution of the ultraviolet LED packaging method, after bonding and fixing the transparent cover plate to the second glue layer, it includes:

[0025] Enclose the transparent cover plate, the first glue layer and the second glue layer in the packaging layer.

[0026] The beneficial effects of the present invention are as follows: By providing a first boss on the end face of the dam, during assembly, the transparent cover plate can be directly in contact with and connected to the first boss, avoiding the offset of the transparent cover plate. During use, the first boss can block the ultraviolet light of the LED device, preventing the ultraviolet light from entering the first adhesive layer and the second adhesive layer, thereby avoiding the cracking of the first adhesive layer and the second adhesive layer and ensuring the airtightness of the LED device during use. Description of the Drawings

[0027] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0028] Figure 1 Schematic diagram of the ultraviolet LED packaging structure according to an embodiment of the present invention.

[0029] Figure 2 Schematic diagram of the ultraviolet LED packaging structure according to another embodiment of the present invention.

[0030] Figure 3 Schematic diagram of the ultraviolet LED packaging structure according to still another embodiment of the present invention.

[0031] Figure 4 Schematic diagram of the ultraviolet LED packaging structure according to another embodiment of the present invention.

[0032] Figure 5 Schematic diagram of the bracket according to an embodiment of the present invention.

[0033] Figure 6 Schematic diagram of the bracket according to another embodiment of the present invention.

[0034] In the figure:

[0035] 1, transparent cover plate; 2, bracket; 201, dam; 2011, first boss; 2012, second boss; 3, first adhesive layer; 4, second adhesive layer; 5, accommodation cavity; 6, encapsulation layer. Detailed Embodiments

[0036] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present invention clearer, the technical solutions of the embodiments of the present invention will be further described in detail below with reference to the drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0037] As Figure 1 and Figure 5As shown in the figure, the present invention provides an ultraviolet LED packaging structure, which includes a bracket 2 and a transparent cover plate 1. The bracket 2 has a receiving cavity 5, and the transparent cover plate 1 is used to seal the receiving cavity 5. The bracket 2 includes an annular dam 201, the receiving cavity 5 is arranged within the dam 201, the end face of the dam 201 is provided with a first boss 2011, the first boss 2011 is connected to the transparent cover plate 1, the first boss 2011 is close to the receiving cavity 5, and a first glue layer 3 is arranged on the side of the end face away from the receiving cavity 5. A second glue layer 4 is arranged between the first boss 2011 and the first glue layer 3. By arranging the first boss 2011 on the end face of the dam 201, during assembly, the transparent cover plate 1 can be directly in contact with and connected to the first boss 2011, avoiding the deviation of the transparent cover plate 1. During use, the first boss 2011 can block the ultraviolet light of the LED device, preventing the ultraviolet light from entering the first glue layer 3 and the second glue layer 4, thereby avoiding the cracking phenomenon of the first glue layer 3 and the second glue layer 4, and ensuring the airtightness of the LED device during use.

[0038] In one embodiment, referring to Figure 1 , the first glue layer 3 is located below the transparent cover plate 1, the height of the first glue layer 3 is not higher than the height of the first boss 2011, and the height of the first glue layer 3 is preferably between 1 / 2 and 1 of the height of the first boss 2011. At this time, both the first glue layer 3 and the second glue layer 4 are bonded to the lower surface of the transparent cover plate 1, improving the appearance effect of the LED device. This ultraviolet LED packaging structure forms a groove for filling the second glue layer by jointly enclosing with the first boss, the dam, and the first glue layer, and places the transparent cover plate on the top of the frame body, which is beneficial to improving the packaging efficiency and reducing the process difficulty of difficult control of the glue dispensing amount. The second layer of glue is formed in a fixed groove. On the one hand, when the dispensing amount of the packaging glue is relatively large, it can ensure that the packaging glue does not flow into the receiving cavity where the LED unit is packaged, causing the glue to be around the ultraviolet chip and the appearance to be abnormal. On the other hand, through the first boss, the glue will not flow into the cavity where the LED chip is packaged, and the ultraviolet light cannot penetrate the first boss, and the phenomenon of the glue being irradiated and cracked by the UVC energy will not occur, improving the aging performance of the ultraviolet LED packaging structure.

[0039] In another embodiment, referring to Figure 3 , the first glue layer 3 is located outside the edge of the transparent cover plate 1, and the height of the first glue layer 3 is higher than the height of the first boss 2011. At this time, the second glue layer 4 is bonded to the lower surface of the transparent cover plate 1, and the first glue layer 3 is bonded to the side surface of the transparent cover plate 1, which can improve the connection strength between the transparent cover plate 1 and the dam 201 of the bracket 2; during assembly, the first glue layer 3 with a higher height can play a limiting role on the transparent cover plate 1, avoiding the displacement of the transparent cover plate 1 and reducing the packaging difficulty of the LED device.

[0040] In other embodiments, the end face of the first adhesive layer 3 can be stepped. At this time, the first adhesive layer 3 is bonded to both the lower surface and the side surface of the transparent cover plate 1, increasing the bonding area between the first adhesive layer 3 and the transparent cover plate 1 and improving the connection strength between the bracket 2 and the transparent cover plate 1.

[0041] Referring to Figure 2 and Figure 6 , in one embodiment, a second boss 2012 is provided on the end face of the dam 201. The second boss 2012 is arranged at intervals on the side of the first boss 2011 away from the accommodation cavity 5. The first adhesive layer 3 is arranged on the second boss 2012, and the second adhesive layer 4 is arranged between the second boss 2012 and the first boss 2011. The height of the second boss 2012 is lower than the height of the first boss 2011. By providing the second boss 2012, during the dispensing operation, the second boss 2012 can provide a reference for the first adhesive layer 3, reducing the forming difficulty of the first adhesive layer 3. At the same time, the second boss 2012 and the dam 201 are integrally formed of metal, improving the airtightness structure of the UV LED packaging structure and enhancing the airtightness. Since the first adhesive layer 3 is arranged on the second boss 2012, to ensure the bonding area between the first adhesive layer 3 and the transparent cover plate 1, the height of the second boss 2012 should be lower than that of the first boss 2011.

[0042] Specifically, the hardness of the first adhesive layer 3 is greater than that of the second adhesive layer 4, and the moisture resistance of the first adhesive layer 3 is better than that of the second adhesive layer 4, which can block the entry of water vapor and improve the packaging airtightness of the product. Since the first adhesive layer 3 is exposed outside the LED device, by setting the first adhesive layer 3 with a greater hardness, the first adhesive layer 3 can protect the second adhesive layer 4 and improve the airtightness of the LED device. In this embodiment, the hardness (shore D, Shore hardness) of the first adhesive layer 3 is greater than 50, and the material of the first adhesive layer 3 can be silicone resin, or other materials such as modified silicone resin and epoxy resin.

[0043] Silicone resin is a thermosetting polyorganosiloxane with a highly cross-linked structure. Due to its special structure, compared with other organic resins, it has excellent heat resistance, cold resistance, weather resistance, electrical insulation, hydrophobicity, anti-sticking and demoulding properties, etc. Therefore, it is widely used as insulating paints for high and low temperatures, heat-resistant coatings, weather-resistant coatings, ablative-resistant coatings, and moulding plastics for high and low temperatures and electrical insulation. Silicone resin is generally prepared from a mixture of organochlorosilanes or organoethoxysilanes through hydrolysis and polycondensation reactions in a mixed solvent. The curing of silicone resin is a process in which it transforms into a thermosetting resin with a three-dimensional network structure that is insoluble and infusible under the action of heat or a catalyst. Classification of silicone resin Silicone resin is a cross-linked semi-inorganic high polymer with a silicon-oxygen-silicon main chain and organic groups connected to silicon atoms. It is produced by the direct method for producing organosilicon monomers. Silicone resin has outstanding weather resistance. Even under strong ultraviolet irradiation, silicone resin is resistant to yellowing. Silicone resin adhesives and silicone adhesives can be classified into adhesives based on silicone resin and adhesives based on silicone rubber according to the raw material sources. The former is mainly used for bonding metals. Silicone resin has good bonding properties for metals such as iron, aluminum, and tin, and is also easy to bond to glass and ceramics, but has poor adhesion to copper.

[0044] The modified silicone resin is a copolymer with a modified silicone resin network structure. Its characteristics are that after the resin forms a film, it has high hardness, which can reach 3-5H without adding fillers, strong adhesion, and good transparency, and is a good temperature-resistant and protective coating. The modified silicone resin has characteristics such as high temperature resistance, aging resistance, radiation resistance, wear resistance, and extremely strong hydrophobicity.

[0045] Epoxy resin is a kind of polymer. It refers to the general term of a class of polymers containing more than two epoxy groups in the molecule. It is a condensation product of epichlorohydrin and bisphenol A or polyhydric alcohol. Due to the chemical activity of the epoxy group, it can be ring-opened with a variety of compounds containing active hydrogen and cured and cross-linked to form a network structure. Therefore, it is a thermosetting resin.

[0046] Specifically, the refractive index of the first glue layer 3 is greater than that of the second glue layer 4. It can be understood that the glue layer with a high refractive index has better sealing performance than the glue layer with a low refractive index, while the glue layer with a low refractive index has a better anti-ultraviolet effect than the glue layer with a high refractive index. In this embodiment, the first glue layer 3 is exposed outside the LED device, while the second glue layer 4 is adjacent to the accommodation cavity 5 of the bracket 2. During use, the probability of the second glue layer 4 being irradiated by ultraviolet rays is greater than that of the first glue layer 3 being irradiated by ultraviolet rays. Therefore, by setting the first glue layer 3 with better sealing performance and the second glue layer 4 with better anti-ultraviolet effect, the sealing effect of the LED device can be improved and the aging speed of the LED device can be reduced. In this embodiment, the first glue layer 3 and the second glue layer 4 can be made of transparent materials or semi-permeable membrane materials. Among them, the refractive index of the first glue layer 3 is between 1.5 and 1.8, and materials such as nano-level titanium dioxide or silicon dioxide can be added to the inside of the first glue layer 3. The refractive index of the second glue layer 4 is between 1.34 and 1.5, and materials such as nano-level titanium dioxide or silicon dioxide can be added to the inside of the second glue layer 4 to improve the bonding strength and hardness of the second glue layer 4.

[0047] Titanium dioxide is an inorganic substance with the chemical formula TiO2. It is non-toxic, has the best opacity, the best whiteness and brightness, and is considered to be one of the best white pigments in the world today. Titanium dioxide has strong adhesion and is not prone to chemical changes. It is widely used in industries such as coatings, plastics, papermaking, printing inks, chemical fibers, rubber, and cosmetics. Titanium dioxide has a good ultraviolet masking effect and is often incorporated into textile fibers as a sunscreen. Ultrafine titanium dioxide powder is also added to sunscreen creams to make sunscreen cosmetics.

[0048] Silicon dioxide is an inorganic substance with the chemical formula SiO2. Silicon atoms and oxygen atoms are arranged in a long-range ordered manner to form crystalline silicon dioxide, and are arranged in a short-range ordered or long-range disordered manner to form amorphous silicon dioxide. Pure natural silicon dioxide crystals are hard, brittle, insoluble, colorless and transparent solids, and are often used in the manufacture of optical instruments, etc.

[0049] The present invention also provides a method for packaging ultraviolet LEDs. Since the above-mentioned ultraviolet LED packaging structure is manufactured, it includes the following steps:

[0050] Perform the first glue-dotting operation on the end face of the dam 201 of the bracket 2 to form the first glue layer 3;

[0051] Perform the second glue-dotting operation on the end face to form the second glue layer 4;

[0052] Bond and fix the transparent cover plate 1 to the second glue layer 4.

[0053] First, form the first glue layer 3 on the end face. A dispensing groove can be formed between the first glue layer 3 and the second glue layer 4, which is beneficial to the formation of the second glue layer 4 and reduces the assembly difficulty of the ultraviolet LED packaging structure.

[0054] Specifically, referring to Figure 5 and Figure 6 , in this embodiment, the first boss 2011, the second boss 2012 and the dam 201 are integrally formed. The first boss 2011 and the second boss 2012 are both formed by the extension of the dam 201. The outer side surface of the second boss 2012 is flush with the outer side surface of the dam 201, and the inner side wall of the first boss 2011 is flush with the inner side wall of the dam 201. During processing, the bracket 2 can be processed first, and part of the material of the bracket 2 can be removed to form the first boss 2011, the second boss 2012 and the dam 201, which can improve the connection strength between the first boss 2011 and the second boss 2012 and the dam 201.

[0055] Preferably, when the distance between the two inner walls of the first glue layer 3 is less than the size of the transparent cover plate 1, the height of the first glue layer 3 is lower than the height of the first boss 2011. When the amount of glue in the second glue layer 4 is relatively large, the excess glue in the second glue layer 4 can overflow from between the second glue layer 4 and the transparent cover plate 1, which can ensure that the transparent cover plate 1 and the first boss 2011 can be directly connected, avoid the second glue layer 4 from flowing into the accommodation cavity 5, and ensure the airtightness during the use of the LED device. Since the excess glue in the second glue layer 4 can overflow outside the LED device, the difficulty of precision control of the glue amount in the second glue layer 4 can be reduced, and the packaging efficiency can be improved.

[0056] Preferably, an overflow port can be provided on the first glue layer 3. At this time, the excess glue on the second glue layer 4 can overflow from the overflow port, further reducing the difficulty of precision control of the glue amount in the second glue layer 4 and improving the packaging efficiency.

[0057] Specifically, referring to Figure 4 , the ultraviolet LED packaging structure further includes a packaging layer 6. The packaging layer 6 wraps the outer surface of the transparent cover plate 1 and shields the first glue layer 3 and the second glue layer 4. The packaging layer 6 can further seal the ultraviolet LED packaging structure and improve the airtightness of the LED device. During packaging, after the transparent cover plate 1 and the second glue layer 4 are bonded and fixed, the transparent cover plate 1, the first glue layer 3 and the second glue layer 4 can be wrapped in the packaging layer 6, which can enable the packaging layer 6 to completely wrap the first glue layer 3 and the second glue layer 4 and also reduce the packaging difficulty of the LED device.

[0058] Specifically, the encapsulation layer 6 is a nanoscale fluorocarbon film with a thickness greater than 100 nanometers. In this embodiment, the thickness of the encapsulation layer 6 is between 200 and 300 nanometers, and its light transmittance is greater than 90%. This can reduce the light loss between the encapsulation layer 6 and the transparent cover plate 1 and improve the light extraction effect of the LED device.

[0059] Specifically, in this embodiment, the materials of the dam 201, the first boss 2011, and the second boss 2012 are metals. Under the bonding action of the first adhesive layer 3 and the second adhesive layer 4, the first boss 2011 and the dam 201 can block moisture from entering the accommodation cavity 5, improving the waterproof performance of the LED device.

Claims

1. An ultraviolet LED packaging structure, comprising a bracket and a transparent cover plate. The bracket has a receiving cavity, and the transparent cover plate seals the receiving cavity. It is characterized in that, The bracket includes an annular dam, the accommodating cavity is arranged within the dam, a first boss is arranged on an end face of the dam, the first boss is connected to the transparent cover plate, the first boss is close to the accommodating cavity, a first adhesive layer is arranged on a side of the end face away from the accommodating cavity, and a second adhesive layer is arranged between the first boss and the first adhesive layer; The first adhesive layer is located outside an edge of the transparent cover plate; The hardness of the first adhesive layer is greater than that of the second adhesive layer; A second boss is arranged on the end face, the second boss is arranged at intervals on a side of the first boss away from the accommodating cavity, the first adhesive layer is arranged on the second boss, the second adhesive layer is arranged between the second boss and the first boss, and the height of the second boss is lower than that of the first boss.

2. The ultraviolet LED packaging structure according to claim 1, characterized in that, The first adhesive layer is at least located below the transparent cover plate.

3. The ultraviolet LED packaging structure according to claim 1, characterized in that, The first adhesive layer is located outside an edge of the transparent cover plate.

4. The ultraviolet LED packaging structure according to claim 1, characterized in that, The first boss and the dam are integrally formed.

5. The ultraviolet LED packaging structure according to claim 1, characterized in that, It includes a packaging layer, the packaging layer wraps around an outer surface of the transparent cover plate and shields the first adhesive layer and the second adhesive layer.

6. The ultraviolet LED packaging structure according to claim 5, characterized in that, The packaging layer is a fluorocarbon film; and / or, The thickness of the packaging layer is greater than 100 nanometers.

7. An ultraviolet LED packaging method for manufacturing the ultraviolet LED packaging structure according to any one of claims 1-6, characterized in that, It includes the following steps: Perform a first dispensing operation on an end face of the bracket dam to form a first adhesive layer; Perform a second dispensing operation on the end face to form a second adhesive layer; Bond and fix the transparent cover plate to the second adhesive layer.

8. The ultraviolet LED packaging method according to claim 7, characterized in that, After bonding and fixing the transparent cover plate to the second adhesive layer, it includes: Enclose the transparent cover plate, the first adhesive layer and the second adhesive layer within the packaging layer.

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