LED packaging method and LED packaging structure

Abstract

The invention provides an LED packaging method and an LED packaging structure. The LED packaging method comprises the steps that a light-emitting chip is packaged on the first side face of a substrate; mixing and stirring a diluent and the first colloid to form a low-viscosity colloid; spraying the low-viscosity colloid on the first side surface of the substrate; standing the substrate so that the low-viscosity colloid is infiltrated between the substrate and the light-emitting chip; and baking the substrate so as to shape the low-viscosity colloid. Thus, a small amount of low-viscosity colloid can rapidly permeate into the gap area between the light-emitting chip and the substrate, the processing cost can be saved, the processing efficiency can be improved, in the subsequent packaging process, bubbles generated in the gap between the substrate and the light-emitting chip due to heating can be avoided, and the packaging quality is improved. Therefore, the appearance attractiveness and the light emitting effect of the packaged product can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of LED products, and in particular to an LED packaging method and an LED packaging structure. Background Art

[0002] During the LED packaging process, after the COB light board is reflowed, there is a gap of 10-30 microns between the chip pad and the substrate pad. During the subsequent spraying of transparent glue and baking, bubbles will be generated in the gap between the chip pad and the substrate pad due to the discharge of heated gas. Such bubbles will affect the appearance of the product and the optical effect. Summary of the Invention

[0003] In view of this, the present application provides an LED packaging method and an LED packaging structure, which can avoid the formation of bubbles in the gap between the substrate and the light-emitting chip due to heat, thereby improving the light output effect of the packaged product.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A method for packaging an LED, comprising:

[0006] Encapsulating a light-emitting chip on the first side of the substrate;

[0007] Mixing and stirring the diluent with the first colloid to form a low-viscosity colloid;

[0008] spraying the low-viscosity colloid on the first side of the substrate;

[0009] leaving the substrate still so that the low-viscosity colloid can penetrate between the substrate and the light-emitting chip;

[0010] The substrate is baked to set the low-viscosity colloid.

[0011] Optionally, the mixing ratio of the diluent to the first colloid is 1-3.

[0012] Optionally, when the diluent and the first colloid are mixed and stirred, centrifugal stirring is performed for 2-5 minutes.

[0013] Optionally, when spraying the low-viscosity colloid on the first side of the substrate, the angle formed by the spraying angle of the nozzle and the substrate is 45-60 degrees, and the distance between the nozzle and the substrate is 5-10 cm.

[0014] Optionally, the thickness of the low-viscosity colloid sprayed on the substrate is 30-50 microns.

[0015] Optionally, when the substrate is left standing, the standing time is 10-60 minutes.

[0016] Optionally, baking the substrate includes:

[0017] Baking the substrate at a baking temperature of 30 degrees for 30 minutes;

[0018] Baking the substrate at a baking temperature of 60 degrees for 30 minutes;

[0019] Baking the substrate at a baking temperature of 150 degrees for 60 minutes;

[0020] Among them, when adjusting the baking temperature, the heating time is 10 minutes.

[0021] Optionally include:

[0022] The second colloid is sprayed or dotted on the first side of the substrate so that the second colloid covers the light-emitting chip and the low-viscosity colloid.

[0023] Optionally, before spraying the low-viscosity colloid on the first side of the substrate, the method further comprises:

[0024] A shielding net is placed on the first side surface of the substrate so that the light-emitting chip is located in the mesh opening of the shielding net;

[0025] Wherein, the size of the opening of the shielding net is larger than 115-125% of the size of the light-emitting chip.

[0026] An LED packaging structure, based on the LED packaging method as described in any of the above items, includes a substrate, a light-emitting chip, a low-viscosity colloid and a second colloid are provided on the first side of the substrate, the low-viscosity colloid is located between the light-emitting chip and the substrate, and the second colloid covers the light-emitting chip.

[0027] The LED packaging method and LED packaging structure provided by the present application are characterized by a low-viscosity colloid formed by mixing a diluent and a first colloid, which has a low viscosity. A small amount of low-viscosity colloid can quickly penetrate into the gap area between the light-emitting chip and the substrate, which can save processing costs and improve processing efficiency. Moreover, the low-viscosity colloid can be sprayed out quickly and accurately from the nozzle, and the thickness of the sprayed glue can be accurately controlled, so that the thickness of the low-viscosity colloid sprayed on the substrate can be better adapted to the gap size between the substrate and the light-emitting chip. In the subsequent packaging process, the formation of bubbles in the gap between the substrate and the light-emitting chip due to heat can be avoided, thereby improving the appearance of the packaged product and the light-emitting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0029] Figure 1 is a cross-sectional view of a light-emitting chip packaged on a substrate according to some embodiments;

[0030] Figure 2 This is a schematic diagram of spraying a low-viscosity colloid on a substrate according to a first embodiment;

[0031] Figure 3 A cross-sectional view of an LED packaging structure shown in a first embodiment;

[0032] Figure 4 This is a schematic diagram showing a second embodiment of placing a shielding net on a substrate;

[0033] Figure 5 This is a schematic diagram of spraying a low-viscosity colloid on a substrate according to a second embodiment;

[0034] Figure 6 This is a cross-sectional view of an LED packaging structure shown in the second embodiment.

[0035] Explanation of the accompanying symbols: 1. substrate; 2. light-emitting chip; 3. low-viscosity colloid; 4. second colloid; 5. nozzle; 6. shielding net. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0037] like Figures 1-6 As shown, an embodiment of the present application provides an LED packaging method for forming an LED packaging structure, comprising the following steps:

[0038] Step S1, encapsulating the light-emitting chip 2 on the first side surface of the substrate 1;

[0039] In step S1, a first pad is provided on the first side of the substrate 1, and a second pad is provided on the light-emitting chip 2. During processing, a layer of solder paste is first pre-coated on the first pad of the substrate 1. The solder paste mainly consists of solder powder, flux, and adhesive. The light-emitting chip 2 is then attached to the first side of the substrate 1 so that the first pad and the second pad are butted against each other. Finally, a reflow process is performed to solder the first and second pads together, thereby completing the packaging of the light-emitting chip 2 and the substrate 1.

[0040] Step S2, mixing and stirring the diluent and the first colloid to form a low-viscosity colloid 3;

[0041] In step S2, the first colloid is mixed with a diluent to reduce its viscosity, which is beneficial for subsequent glue spraying and infiltration. Here, the diluent can be xylene, ether, or other environmentally friendly materials. The mixing ratio of the diluent to the first colloid is 1-3, that is, the diluent is 1-3 times the first colloid. In the optimal solution, the diluent is twice the first colloid, which has both good viscosity and good fluidity.

[0042] Step S3, spraying a low-viscosity colloid 3 on the first side of the substrate 1;

[0043] Step S4: leaving the substrate 1 still so that the low-viscosity colloid 3 can penetrate between the substrate 1 and the light-emitting chip 2;

[0044] In step S3 and step S4, the diluted first colloid (i.e., low-viscosity colloid 3) is sprayed on the first side of the substrate 1. Due to its relatively low viscosity, a smaller amount of low-viscosity colloid 3 can quickly penetrate into the gap area between the light-emitting chip 2 and the substrate 1, which can save processing costs and improve processing efficiency. Moreover, the low-viscosity colloid 3 can be sprayed quickly and accurately by the nozzle 5, and the amount of glue sprayed at a single time can be as low as 15 microns. The thickness of the sprayed glue can be accurately controlled, so that the thickness of the low-viscosity colloid 3 sprayed on the substrate 1 can be better adapted to the gap size between the substrate 1 and the light-emitting chip 2. Here, when the substrate 1 is left to stand, the standing time is 10-60 minutes, which is conducive to allowing the low-viscosity colloid 3 to fully infiltrate the gap area between the substrate 1 and the light-emitting chip 2, thereby achieving 100% filling of the gap area between the substrate 1 and the light-emitting chip 2.

[0045] Step S5: baking the substrate 1 to solidify the low-viscosity colloid 3.

[0046] In step S5, by baking the low-viscosity colloid 3 on the substrate 1 (defined here as the first baking of the substrate 1), the low-viscosity colloid 3 can be quickly shaped, and then the low-viscosity colloid 3 is filled in the gap between the substrate 1 and the light-emitting chip 2. In the subsequent packaging process, bubbles can be avoided in the gap between the substrate 1 and the light-emitting chip 2 due to heat, thereby improving the appearance of the packaged product and the light-emitting effect.

[0047] In a specific solution, when baking the substrate 1 for the first time, a segmented baking method can be adopted, for example, baking can be divided into three stages. In the first stage, the substrate is baked at a baking temperature of 30 degrees for 130 minutes; in the second stage, the substrate is baked at a baking temperature of 60 degrees for 130 minutes; in the third stage, the substrate is baked at a baking temperature of 150 degrees for 160 minutes. Among them, when adjusting the baking temperature, the heating time is 10 minutes. In this way, the temperature of the substrate 1 can be gradually increased, which is conducive to the stable and rapid solidification of the low-viscosity colloid 3, avoiding the low-viscosity colloid 3 from being quickly heated and collided to affect the connection between the substrate 1 and the light-emitting chip 2, and has better safety.

[0048] In this solution, by mixing the first colloid with a diluent, the viscosity of the first colloid can be reduced. A smaller amount of low-viscosity colloid 3 can quickly penetrate the gap between the light-emitting chip 2 and the substrate 1, saving processing costs and improving processing efficiency. Furthermore, the low-viscosity colloid 3 can be quickly and accurately sprayed from the nozzle 5, and the thickness of the sprayed glue can be precisely controlled, thereby ensuring that the thickness of the low-viscosity colloid 3 sprayed on the substrate 1 is better adapted to the gap size between the substrate 1 and the light-emitting chip 2. During the subsequent packaging process, the formation of bubbles in the gap between the substrate 1 and the light-emitting chip 2 due to heat can be avoided, thereby improving the aesthetic appearance and light output of the packaged product.

[0049] In some embodiments, after the diluent and the first colloid are mixed, centrifugal stirring is performed for 2-5 minutes to fully mix the diluent and the first colloid, which is beneficial to improving the stability and reliability of subsequent glue spraying and also helps the low-viscosity colloid 3 to infiltrate between the substrate 1 and the light-emitting chip 2.

[0050] Using a spray machine to perform glue spraying operations to spray the low-viscosity colloid 3 onto the first side of the substrate 1 is beneficial to improving the level of automation and the uniformity of glue spraying. The spray machine has a nozzle 5, and the angle formed by the spray angle of the nozzle 5 and the substrate 1 is 45-60 degrees. When spraying the low-viscosity colloid 3, the low-viscosity colloid 3 can be sprayed toward the gap area between the substrate 1 and the light-emitting chip 2, which is more conducive to the low-viscosity colloid 3 infiltrating toward the spacing area between the substrate 1 and the light-emitting chip 2, thereby improving processing efficiency. The distance between the nozzle 5 and the substrate 1 is 5-10 cm, so that the low-viscosity colloid 3 can be sprayed from the nozzle 5 and fully dispersed and then fall onto the substrate 1, which is beneficial to improving the uniformity of glue spraying.

[0051] The thickness of the low-viscosity colloid 3 sprayed on the substrate 1 is 30-50 microns. Since the gap between the substrate 1 and the light-emitting chip 2 is 10-30 microns, the thickness of the low-viscosity colloid 3 can be designed so that the height of the low-viscosity colloid 3 is higher than the bottom of the light-emitting chip 2. Under the action of gravity, the low-viscosity colloid 3 can quickly infiltrate the gap between the substrate 1 and the light-emitting chip 2 and completely fill the gap between the substrate 1 and the light-emitting chip 2. Moreover, the low-viscosity colloid 3 can adhere to the outer periphery of the light-emitting chip 2. After the low-viscosity colloid 3 is cured, it can seal the gap between the substrate 1 and the light-emitting chip 2, thereby protecting the pad connection between the substrate 1 and the light-emitting chip 2.

[0052] like Figure 1-3 As shown, in the first embodiment, after the low-viscosity colloid 3 is statically baked and formed, the second colloid 4 is sprayed on the first side of the substrate 1 by a full-coverage spraying method. The second colloid 4 covers the light-emitting chip 2 and the side of the low-viscosity colloid 3 away from the substrate 1.

[0053] Among them, the thickness of the second colloid 4 sprayed on the first side of the substrate 1 is greater than 0.1 mm, which is beneficial to improving the uniformity of light output. When baking the second colloid 4 (here defined as the second baking of the substrate 1), a segmented baking method can be adopted, for example, baking is divided into three sections. In the first section, the substrate is baked for 130 minutes at a baking temperature of 30 degrees; in the second section, the substrate is baked for 130 minutes at a baking temperature of 60 degrees; in the third section, the substrate is baked for 160 minutes at a baking temperature of 150 degrees. Among them, when adjusting the baking temperature, the heating time is 10 minutes. In this way, the temperature of the substrate 1 can be gradually increased, which is beneficial to the stable and rapid solidification of the second colloid 4, and has better safety.

[0054] like Figure 1 、 4 -6, in the second embodiment, after the low-viscosity colloid 3 is statically baked and formed, a second colloid 4 is spot-coated on the first side of the substrate 1 using a glue sprayer, and the second colloid 4 covers the light-emitting chip 2 and the side of the low-viscosity colloid 3 away from the substrate 1.

[0055] When baking the second colloid 4 (herein defined as the second baking of the substrate 1), a staged baking method can be used, for example, in two stages. In the first stage, the substrate is baked at a baking temperature of 100 degrees for 130 minutes; in the second stage, the substrate is baked at a baking temperature of 150 degrees for 160 minutes. When adjusting the baking temperature, the heating time is 10 minutes. This allows the temperature of the substrate 1 to be gradually increased, which facilitates the stable and rapid curing of the second colloid 4 and improves safety.

[0056] After encapsulating the light-emitting chip 2 on the first side of the substrate 1 and before spraying the low-viscosity colloid 3 on the first side of the substrate 1, a shielding net 6 is placed on the first side of the substrate 1. The light-emitting chip 2 is located within the mesh opening of the shielding net 6 and is shielded between two adjacent light-emitting chips 2 by the shielding net 6. During the first spraying, the low-viscosity colloid 3 can only be sprayed on the light-emitting chip 2 and the surrounding area, thereby achieving localized spraying of the low-viscosity colloid 3 on the first side of the substrate 1. Here, the shielding net 6 can be set as a steel mesh. The mesh opening size of the shielding net 6 is larger than 115-125% of the size of the light-emitting chip 2, and the mesh opening size of the shielding net 6 is less than or equal to 50-90% of the size of the second colloid 4 after molding. For example, in the left-right direction as shown in the figure, the size of the shielding net 6 is larger than 1.2 times the size of the light-emitting chip 2 and smaller than 0.5-0.9 times the size of the second colloid 4.

[0057] The present invention provides an LED packaging structure based on the LED packaging method described in the above embodiments. The LED packaging structure includes a substrate 1, with a light-emitting chip 2, a low-viscosity colloid 3, and a second colloid 4 disposed on a first side of the substrate 1. The low-viscosity colloid 3 is located between the light-emitting chip 2 and the substrate 1, and the second colloid 4 covers the light-emitting chip 2.

[0058] The low-viscosity colloid 3 is a mixture of a diluent and a first colloid and has a low viscosity. Using a small amount of low-viscosity colloid 3 can quickly penetrate the gap between the light-emitting chip 2 and the substrate 1, saving processing costs and improving processing efficiency. Furthermore, the low-viscosity colloid 3 can be quickly and accurately sprayed from the nozzle 5, and the thickness of the sprayed glue can be precisely controlled, thereby ensuring that the thickness of the low-viscosity colloid 3 sprayed on the substrate 1 is better adapted to the gap size between the substrate 1 and the light-emitting chip 2. During the subsequent packaging process, the formation of bubbles in the gap between the substrate 1 and the light-emitting chip 2 due to heat can be avoided, thereby improving the aesthetic appearance and light output of the packaged product.

[0059] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0060] The block diagrams of the devices, devices, equipment, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the words "and / or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0061] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed and / or recombined, and such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0062] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0063] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly illustrate the technical solutions and cannot be used to limit the scope of protection of the present application.

[0064] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for encapsulating an LED, characterized in that: include: Encapsulating a light-emitting chip (2) on a first side surface of the substrate (1); Mixing and stirring the diluent with the first colloid to form a low-viscosity colloid (3); Spraying the low-viscosity colloid (3) on the first side of the substrate (1); The substrate (1) is allowed to stand still so that the low-viscosity colloid (3) penetrates between the substrate (1) and the light-emitting chip (2); The substrate (1) is baked to shape the low-viscosity colloid (3).

2. The LED packaging method according to claim 1, wherein: The mixing ratio of the diluent to the first colloid is 1-3.

3. The LED packaging method according to claim 1, wherein: When the diluent and the first colloid are mixed and stirred, centrifugal stirring is performed for 2-5 minutes.

4. The LED packaging method according to claim 1, wherein: When the low-viscosity colloid (3) is sprayed on the first side of the substrate (1), the angle formed by the spraying angle of the nozzle (5) and the substrate (1) is 45-60 degrees, and the distance between the nozzle (5) and the substrate (1) is 5-10 centimeters.

5. The LED packaging method according to claim 1, wherein: The thickness of the low-viscosity colloid (3) sprayed on the substrate (1) is 30-50 microns.

6. The LED packaging method according to claim 1, wherein: When the substrate (1) is left standing, the standing time is 10-60 minutes.

7. The LED packaging method according to claim 1, wherein: The baking of the substrate (1) comprises: Baking the substrate (1) at a baking temperature of 30 degrees for 30 minutes; Baking the substrate (1) at a baking temperature of 60 degrees for 30 minutes; Baking the substrate (1) at a baking temperature of 150 degrees for 60 minutes; Among them, when adjusting the baking temperature, the heating time is 10 minutes.

8. The LED packaging method according to claim 1, wherein: include: The second colloid (4) is sprayed or spot-coated on the first side of the substrate (1), so that the second colloid (4) covers the light-emitting chip (2) and the low-viscosity colloid (3).

9. The LED packaging method according to claim 1, wherein: Before spraying the low-viscosity colloid (3) on the first side of the substrate (1), the process includes: A shielding net (6) is placed on the first side of the substrate (1) so that the light-emitting chip (2) is located within the opening of the shielding net (6); The size of the opening of the shielding net (6) is greater than 115-125% of the size of the light-emitting chip (2).

10. An LED packaging structure, characterized in that: The LED packaging method according to any one of claims 1 to 9 comprises a substrate (1), a light-emitting chip (2), a low-viscosity colloid (3) and a second colloid (4) being provided on a first side of the substrate (1), the low-viscosity colloid (3) being located between the light-emitting chip (2) and the substrate (1), and the second colloid (4) covering the light-emitting chip (2).

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