Ultraviolet LED packaging structure

Abstract

The utility model relates to the technical field of LED packaging structures, in particular to an ultraviolet LED packaging structure, which comprises a substrate and an LED chip mounted on the substrate. A support is fixedly installed above the base plate, a step position is formed on the support, a lens is placed on the step position, at least one gluing groove is formed in the upper end of the step position, and a metal coating is formed at the bottom of the lens. The glue is filled into the gluing groove, and the gluing groove can block direct irradiation of UV light through the side wall, so that the effect of protecting the glue is achieved; and on the other hand, the gluing groove can store glue, compared with a traditional plane structure, flowing of the glue can be limited, glue flowing and glue overflowing in the glue coating process are solved, the product quality is optimized, and then the packaging consistency and reliability are improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to LED packaging structure technical field especially relates to a kind of ultraviolet LED packaging structure. BACKGROUND

[0002] The packaging structure of UV LED mainly includes three parts, substrate, chip and optical lens. The conventional packaging mode is generally to use glue, such as silicone glue, epoxy glue, instant dry glue and other glue to bond the optical lens and ceramic substrate. This process has lower production cost and higher operability. The specific packaging structure is shown in the drawings of the specification Figure 1 Wherein the bracket 2 is fixed on the ceramic base 1, and the lens 3 is adhered to the step position on the upper side of the bracket 2.

[0003] However, in the field of UV LED, with the shortening of chip wavelength, deep ultraviolet light has a significant aging and destructive effect on glue, affecting the reliability of packaging.

[0004] Therefore, in order to reduce the influence of deep ultraviolet light on glue, we propose a kind of ultraviolet LED packaging structure. INVENTION CONTENTS

[0005] The utility model aims at solving the shortening of chip wavelength in the prior art, deep ultraviolet light has a significant aging and destructive effect on glue, and proposes an ultraviolet LED packaging structure.

[0006] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0007] Design a kind of ultraviolet LED packaging structure, including:

[0008] Substrate and LED chip mounted on the substrate;

[0009] A bracket is fixedly installed above the substrate, the bracket is formed with a step position, a lens is placed on the step position, wherein the upper end of the step position has at least one glue coating groove, the bottom of the lens is formed with a metal plating layer, and the metal plating layer and the glue layer in the glue coating groove are bonded.

[0010] Further, the glue coating groove is provided with two;

[0011] The two glue coating grooves are configured with glue sealing outer groove and glue sealing inner groove from outside to inside.

[0012] Further, the glue sealing outer groove is filled with epoxy resin glue layer, and the glue sealing inner groove is filled with silicone glue layer.

[0013] Further, the overflow glue groove is formed between the outer glue sealing groove and the inner glue sealing groove, and the overflow glue groove is formed at the upper end of the step position.

[0014] Further, the distance between the overflow glue groove and the inner glue sealing groove is I, and the distance between the inner glue sealing groove and the inner edge of the step position is L, and the length of the I is less than the length of the L.

[0015] Further, the metal plating layer comprises a metal transition layer, an aluminum metal layer and a protective layer, and the metal transition layer, the aluminum metal layer and the protective layer are sequentially formed from inside to outside at the lower end of the lens.

[0016] The cross-sectional width of the metal plating layer is consistent with the width of the step position.

[0017] Further, the metal transition layer is a metal layer of nickel, titanium, chromium or gold, and the thickness of the metal transition layer is not greater than 100 nm.

[0018] The thickness of the aluminum metal layer is 200 nm-5 um, and the protective layer is a metal layer of silicon dioxide, silicon nitride, MgF2, gold or nickel, and the thickness of the protective layer is not greater than 500 nm.

[0019] Further, the support is an aluminum piece, a copper piece or a ceramic piece.

[0020] The ultraviolet LED packaging structure has the beneficial effects that in the ultraviolet LED packaging structure, the traditional plane step is made into a groove structure, and glue is filled into the glue coating groove, the glue coating groove can block the direct UV light through the side wall, and the glue coating groove can store the glue, compared with the traditional plane structure, the glue coating groove can limit the flow of the glue, solves the glue flow and overflow in the glue coating process, optimizes the product quality, and then improves the consistency and reliability of the packaging. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a schematic diagram of the packaging structure of the prior art;

[0022] Figure 2 It is a schematic diagram of the substrate structure of the utility model;

[0023] Figure 3 It is a schematic diagram of the glue coating groove structure of the utility model;

[0024] Figure 4 It is a schematic diagram of the lens structure of the utility model;

[0025] Figure 5 It is a schematic diagram of the metal plating layer structure of the utility model;

[0026] Figure 6 It is a schematic diagram of the structure of the utility model.

[0027] In the figure: 1, substrate; 10, support; 11, step position; 12, glue coating groove; 121, glue sealing outer groove; 122, glue sealing inner groove; 123, glue overflow groove; 2, LED chip; 3, lens; 4, metal plating layer; 41, metal transition layer; 42, aluminum metal layer; 43, protective layer. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments.

[0029] Reference Figures 2-6 For an embodiment of the utility model, it discloses a kind of ultraviolet LED packaging structures, this structure retains glue lens process while, using new structure design increases ultraviolet light reflection and protects glue, specific including substrate 1 and install on the LED chip 2 of substrate 1;

[0030] Support 10 is fixedly installed above the substrate 1, the support 10 is formed with step position 11, of course, the support 10 in the embodiment should be set to annular structure, the step position 11 is formed at the inner side of the support 10 to be used for the bearing of lens 3, the support 10 in the embodiment is aluminum piece, copper piece or ceramic piece, as preferred, ceramic piece is used, since metal substrate is more difficult to make electrode, here preferred ceramic support is because ultraviolet LED power is large and efficiency is low, chip needs good heat conduction;

[0031] The lens 3 is placed on the step position 11, wherein the upper end of the step position 11 has at least one glue coating groove 12, the bottom of the lens 3 is formed with a metal plating layer 4, and the metal plating layer 4 and the glue layer in the glue coating groove 12 are bonded.

[0032] That is to say, in the embodiment, the traditional flat step is made into a groove structure, and the glue is filled into the glue coating groove 12. The glue coating groove 12 can block the direct UV light through the side wall, thereby protecting the glue. On the other hand, the glue coating groove 12 can store glue. Compared with the traditional flat structure, the flow of glue can be limited, the glue flow and overflow in the glue coating process are solved, the quality of the product is optimized, and the consistency and reliability of the packaging are improved.

[0033] In some embodiments, the glue coating groove 12 in the utility model is provided with two;

[0034] The two glue coating grooves 12 are configured with a glue sealing outer groove 121 and a glue sealing inner groove 122 from outside to inside, such as Figure 2 And Figure 6As shown, the outer groove surface of the glue sealing outer groove 121 or the single glue coating groove 12 and the inner side surface of the support 10 are close to each other in the embodiment, and as preferred, when the glue sealing outer groove 121 and the glue sealing inner groove 122 as shown are adopted, the outer groove surface of the glue sealing outer groove 121 and the inner side surface of the support 10 are flushly arranged; when the single glue coating groove 12 as shown is adopted, the outer groove surface of the glue coating groove 12 and the inner side surface of the support 10 are flushly arranged. Figure 2 As shown, the outer groove surface of the glue sealing outer groove 121 or the single glue coating groove 12 and the inner side surface of the support 10 are close to each other in the embodiment, and as preferred, when the glue sealing outer groove 121 and the glue sealing inner groove 122 as shown are adopted, the outer groove surface of the glue sealing outer groove 121 and the inner side surface of the support 10 are flushly arranged; when the single glue coating groove 12 as shown is adopted, the outer groove surface of the glue coating groove 12 and the inner side surface of the support 10 are flushly arranged. Figure 6 As shown, the outer groove surface of the glue sealing outer groove 121 or the single glue coating groove 12 and the inner side surface of the support 10 are close to each other in the embodiment, and as preferred, when the glue sealing outer groove 121 and the glue sealing inner groove 122 as shown are adopted, the outer groove surface of the glue sealing outer groove 121 and the inner side surface of the support 10 are flushly arranged; when the single glue coating groove 12 as shown is adopted, the outer groove surface of the glue coating groove 12 and the inner side surface of the support 10 are flushly arranged.

[0035] That is, by adopting the design of two glue coating grooves 12 in the embodiment, the following advantages of the glue coating grooves 12 are increased:

[0036] The increase of the glue coating grooves 12 can increase the contact area of the glue and the support 10, and increase the bonding reliability;

[0037] In addition, the increase of the glue coating grooves 12 can perform filling of multiple types and multiple glues; for example, in terms of air tightness, water vapor molecules always invade from the outside; in the process of air tightness decline after packaging aging, the glue sealing outer groove 121 is always invaded first, but after the glue sealing property of the glue sealing outer groove 121 declines, the glue of the glue sealing inner groove 122 is still used for packaging protection, which is equivalent to multiple protection of the air tightness of the packaging, and the bonding property and the air tightness are greatly improved, and the reliability of the packaging is increased.

[0038] Specifically, the glue sealing outer groove 121 is filled with an epoxy resin glue layer, and the glue sealing inner groove 122 is filled with a silicone glue layer. Since it is difficult for conventional packaging glue to have multiple excellent properties at the same time, for example, the epoxy resin has high curing hardness and water and oxygen isolation properties, but poor temperature resistance and is easily degraded and aged by ultraviolet light; the silicone glue has certain ultraviolet resistance and good temperature resistance, but has hydrophilicity and cannot isolate water vapor well. Therefore, the epoxy resin is filled in the glue sealing outer groove 121, and the silicone glue is filled in the glue sealing inner groove 122 in the embodiment, so that the epoxy resin can have good sealing effect, and the temperature resistance of the silicone glue can further consolidate the reliability of the packaging.

[0039] In addition, considering the actual production link, it is unavoidable that the glue spills out, and the spilled glue exists in the form of internal overflow, so the glue storage groove is further optimized, and the overflow groove 123 formed between the glue sealing outer groove 121 and the glue sealing inner groove 122 is further included in the embodiment, and the overflow groove 123 is formed at the upper end of the step position 11.

[0040] Specifically, the distance between the overflow groove 123 and the inner groove 122 for sealing glue is I, the distance between the inner groove 122 for sealing glue and the inner edge of the step position 11 is L, and the length of I is less than the length of L.

[0041] In the embodiment, the distance l between the inner groove 122 for sealing glue and the overflow groove 123 should be less than the distance L between the inner groove for sealing glue and the edge of the support, and the width difference is preferably 1.5 times. The shorter path of the overflow groove 123 can effectively alleviate the pressure when the glue overflows from the glue coating groove 12, and reduce the amount of packaging glue overflowing from the side wall of the support 10. Because the packaging glue overflowing into the support 10 will be discolored or light-absorbed by deep ultraviolet aging, it will further affect the light output of the ultraviolet LED.

[0042] Specifically, the production process conditions of the product are in a nitrogen environment, which can effectively reduce the capture of water vapor or harmful gas in the air by the glue, and further, the production environment can be preferably operated in a low vacuum environment. Not only can it isolate water vapor and harmful gas, but it can also avoid the generation of bubbles in the production process.

[0043] In addition, since the metal plating layer 4 is a continuous plane, because the lens is generally a quartz piece, it is difficult to process, it is difficult to make a microstructure, the cost is high, and the consistency is poor, so the lens surface is generally a continuous plane. Water vapor and harmful molecules will diffuse along the contact surface between the packaging glue and the metal plating layer 4, and there may be a certain probability of diffusing into the LED chip 2 in the support 10, thereby degrading the chip;

[0044] Therefore, in the scheme of operating in a low-pressure vacuum environment, the overflow groove 123 is in a low-pressure environment. If the outer ring sealing glue fails to some extent, even if water vapor and harmful molecules diffuse inward, they will also preferentially accumulate in the overflow groove 123. When the water vapor and harmful molecules in the overflow groove 123 diffuse inward, they need to accumulate to a certain concentration, which will take a longer process, thereby greatly improving the use reliability of the device. Moreover, harmful molecules or water vapor entering the overflow groove 123 and accumulating will corrode the metal plating layer 4 at the position corresponding to the overflow groove 123. The user can more easily discover that the device sealing glue has a failure risk, and the problem can be discovered before the LED chip 2 deteriorates, so that the abnormal device can be replaced in advance.

[0045] In some embodiments, the metal plating layer 4 in the utility model comprises a metal transition layer 41, an aluminum metal layer 42 and a protective layer 43, and the metal transition layer 41, the aluminum metal layer 42 and the protective layer 43 are sequentially formed from inside to outside at the lower end of the lens 3. The aluminum metal layer 42 is a single-layer aluminum, which can also be a multi-layer stack. The actual multi-layer reflective effect is better, such as Al / MgF2, Al / SiO2 multi-layer stack, etc., but the cost is higher. The person skilled in the art can select according to the actual needs.

[0046] The cross-sectional width of the metal plating layer 4 is consistent with the width of the step position 11.

[0047] The advantages of the glue coating groove 12 have been described above. After the ultraviolet light exits, a part of the refracted light will return to irradiate the glue, and after the lens 3 is plated with aluminum, this part of light can be reflected out, which can increase the light output while protecting the glue. For metal plating layers such as aluminum, it is extremely easy to oxidize in the air, and compared with metal aluminum, aluminum oxide has a higher deep ultraviolet light absorption rate, which in turn causes the light output of the ultraviolet LED to decrease. However, for the two-dimensional planar metal plating layer 4, the upper surface thereof is directly attached to the lens 3 and does not contact the air, so it can maintain a high deep ultraviolet reflectivity for a long time, thereby improving the light output of the light source.

[0048] In addition, before plating with aluminum, a specific area is roughened, which is the edge of the lens 3, i.e., the bonding position of the lens 3 and the step position 11 mentioned above. Compared with a smooth plane, roughening of the lens 3 is beneficial to the adhesion of the metal plating layer 4 to the lens 3. Since the glue is directly bonded to the metal plating layer 4, the adhesion of the metal plating layer 4 to the lens 3 directly affects the packaging reliability of the light source.

[0049] The width of the metal plating layer 4 at the edge of the lens 3 does not exceed the step position 11 of the support 10, so as to ensure that the metal plating layer 4 does not affect the light emission in the support 10. The optimal width is consistent with the edge of the step position 11 of the support 10.

[0050] On the basis of the above embodiment, the metal transition layer 41 in the present embodiment is a metal layer of nickel, titanium, chromium or gold, and the thickness thereof is not greater than 100 nm. In the present embodiment, the thickness is preferably less than 5 nm. If the metal transition layer 41 is too thick, it will absorb the UVC light that should be reflected. If it is too thin, it will affect the adhesion.

[0051] The thickness of the aluminum metal layer 42 is 200 nm-5 um. The protective layer 43 is a metal layer of silicon dioxide, silicon nitride, MgF2, gold or nickel, and the thickness thereof is not greater than 500 nm. In the present embodiment, the thickness is preferably less than 50 nm.

[0052] After roughening the lens 3, a metal transition layer 41 is plated first, followed by an aluminum metal layer 42 and then a protective layer 43. Preferably, the metal chromium has good corrosion resistance and metal hardness, and has strong adhesion to the lens 3. As a transition metal layer 41, it can grow a flat metal film on the glass. Compared with other metals, it has a more similar crystal lattice structure, which is more conducive to the growth of other metal materials, thereby improving the reliability of the metal plating layer 4.

[0053] In addition, since the adhesion between the aluminum metal layer 42 and the lens 3 is poor, a metal transition layer 41 is added therebetween. On the one hand, the adhesion between the metal coating layer 4 and the glass lens 3 is improved; and a protective layer 43 is further added on the aluminum metal layer 42, which can further protect the aluminum metal from oxidation.

[0054] It should be noted that the process of the metal coating layer 4 can be selected from electroplating, thermal evaporation and sputtering: electroplating metal is a general and economical method, which forms a metal film on the surface of the glass lens 3 by applying an electric field in the electrolyte. However, electroplating also has some disadvantages, such as thin film, impurities, rough metal layer and low adhesion between the glass lens 3, and the reliability is not strong. In order to improve the reliability of the coating, the process environment is selected in a vacuum environment, and thermal evaporation, magnetron sputtering and the like can be considered.

[0055] The above is only the preferred specific implementation of the present application, but the protection scope of the present application is not limited to this. Any skilled person in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered in the protection scope of the present application.

Claims

1. A UV LED packaging structure, characterized in that, include: A substrate (1) and an LED chip (2) mounted on the substrate (1); A bracket (10) is fixedly installed above the substrate (1). A step (11) is formed on the bracket (10). A lens (3) is placed on the step (11). The upper end of the step (11) has at least one adhesive groove (12). A metal plating layer (4) is formed on the bottom of the lens (3). The metal plating layer (4) and the adhesive layer in the adhesive groove (12) are bonded together.

2. The ultraviolet LED packaging structure according to claim 1, characterized in that: Two glue-applying tanks (12) are provided; The two glue application tanks (12) are configured from the outside in with an outer glue sealing tank (121) and an inner glue sealing tank (122).

3. The ultraviolet LED packaging structure according to claim 2, characterized in that: The outer sealing groove (121) is filled with an epoxy resin adhesive layer, and the inner sealing groove (122) is filled with an organic silicone layer.

4. The ultraviolet LED packaging structure according to claim 2, characterized in that: It also includes an overflow groove (123) formed between the outer sealing groove (121) and the inner sealing groove (122), the overflow groove (123) being formed at the upper end of the step position (11).

5. The ultraviolet LED packaging structure according to claim 4, characterized in that: The distance between the overflow groove (123) and the sealing groove (122) is I, and the distance between the inner edge of the sealing groove (122) and the step position (11) is L. The length of I is less than the length of L.

6. The ultraviolet LED packaging structure according to claim 1, characterized in that: The metal coating (4) includes a metal transition layer (41), an aluminum metal layer (42), and a protective layer (43), which are formed sequentially from the inside to the outside at the lower end of the lens (3). The cross-sectional width of the metal coating (4) is the same as the width of the step (11).

7. The ultraviolet LED packaging structure according to claim 6, characterized in that: The metal transition layer (41) is a metal layer of nickel, titanium, chromium or gold, and its thickness is not greater than 100 nm. The thickness of the aluminum metal layer (42) is 200nm-5um; the protective layer (43) is a metal layer of silicon dioxide, silicon nitride, MgF2, gold or nickel, with a thickness of no more than 500nm.

8. A UV LED packaging structure according to any one of claims 1-7, characterized in that: The bracket (10) is made of aluminum, copper or ceramic.

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