Packaging layer, LED package and LED screen

Abstract

The invention provides an encapsulation layer. The encapsulation layer comprises a colloid, a first filler and a second filler, the first filler and the second filler are uniformly mixed in the colloid; the first filler is granular, and the second filler is flaky; the first filler and the second filler are both hydrophobic and light-transmitting inorganic materials, and the colloid is a light-transmitting colloid. The packaging layer provided by the invention is mixed with two different forms of fillers to form a composite material, so that the water vapor barrier property of the packaging layer can be improved, and the service life of an LED packaging product can be prolonged when the packaging layer is applied to the field of LED packaging.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a packaging layer, an LED package and an LED screen. Background Art

[0002] LED chips are electroluminescent electronic components that typically require encapsulation to prevent moisture intrusion that could cause short circuits or corrosion. For example, the LED chip can be mounted on a carrier and then covered with encapsulant to isolate it from moisture. Common encapsulants are epoxy or silicone, with epoxy generally offering better airtightness than silicone. The effectiveness of the encapsulant in isolating moisture from the chip depends on its thickness: thicker the encapsulant, the better the barrier. However, this increases the thickness of the LED package. Furthermore, since LED chips generate light and heat during operation, using epoxy as an encapsulant can degrade over time, reducing its airtightness.

[0003] How to improve the airtightness of the packaging layer is a technical problem to be solved in this field. Summary of the Invention

[0004] The present invention provides a packaging layer having the advantage of good airtightness. The scheme of the present invention is as follows: An encapsulation layer, characterized in that it includes a colloid, a first filler, and a second filler; the first filler and the second filler are uniformly mixed in the colloid; the first filler is granular and the second filler is flake-shaped; the first filler and the second filler are both hydrophobic and light-transmitting inorganic materials, and the colloid is a light-transmitting colloid.

[0005] The present invention also provides an LED package, comprising a carrier, an LED chip and the above-mentioned packaging layer, wherein the LED chip is mounted on the carrier, the packaging layer covers the LED chip, and the side and top surfaces of the LED chip are covered by the packaging layer without being blocked by any other components.

[0006] The present invention also provides an LED package, comprising a carrier, an LED chip and the above-mentioned packaging layer, wherein the carrier is provided with a recess for mounting the LED chip, the LED chip is mounted in the recess, and the packaging layer fills the recess and covers the LED chip.

[0007] The present invention also provides an LED screen comprising a circuit board, a plurality of LED chips, and the packaging layer according to claim 1; the plurality of LED chips are soldered on the circuit board, and the packaging layer covers the light-emitting units and the circuit board.

[0008] The encapsulation layer provided by the present invention mixes a granular first filler and a flaky second filler in a colloid. If water vapor invades the encapsulation layer, the presence of the first filler and the second filler can extend the invasion path of the water vapor, thereby improving the airtightness of the encapsulation layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0010] Figure 1a FIG. 1 is a schematic diagram of a cross-sectional structure of an encapsulation layer provided in Example 1; Figure 1b FIG2 is a schematic diagram of the cross-sectional structure of another encapsulation layer provided in Example 1; Figure 2a A schematic diagram of the front structure of an LED package provided in Example 2; Figure 2b for Figure 2a AA cross-section of Figure 3a for Figure 3b BB cross-section diagram; Figure 3b A schematic diagram of the front structure of another LED package provided in Example 3; Figure 4a for Figure 4b CC cross-section diagram; Figure 4b This is a schematic diagram of the front structure of an LED screen provided in Example 4. DETAILED DESCRIPTION

[0011] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be understood as limiting the present application. In the description of the present application, the meaning of "multiple" is two or more, and the meaning of "multiple" is two or more, unless otherwise clearly defined.

[0012] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings. Example 1

[0013] refer to Figure 1aAs shown, this embodiment provides an encapsulation layer 10, including a colloid 11, a first filler 12, and a second filler 13. The first filler 12 and the second filler 13 are uniformly mixed in the colloid 11; the first filler 12 is granular, and the second filler 13 is flake-shaped; the first filler 12 and the second filler 13 are both hydrophobic and light-transmitting inorganic materials, and the colloid 11 is a light-transmitting colloid.

[0014] The encapsulation layer 10 can be used to encapsulate LED chips. The first filler 12, the second filler 13, and the colloid 11 are all light-transmissive, and the light emitted by the LED chip can be emitted through the encapsulation layer 10. The first filler 12 has the function of strengthening the toughness of the encapsulation layer 10 and mixing light, while also improving the heat dissipation capacity of the encapsulation layer 10 and reducing the internal stress of the glue 11 itself. The mixing of the first filler 12 and the second filler 13 also has the function of breaking up each other, preventing the first filler 12 or the second filler 13 from excessively agglomerating, thereby causing the structure of the encapsulation layer 10 to be uneven and causing local deformation. The second filler 13 is randomly distributed in the colloid to form a "labyrinth sealing effect" or a similar effect, which can block the penetration of oxygen and water vapor and has the function of increasing the airtightness of the encapsulation layer 10. Its unique two-dimensional structure realizes the synergistic enhancement of physical interlocking and chemical bonds in the colloid 11, optimizes optical uniformity, and improves the mechanical properties and barrier properties of the encapsulation layer 10. Colloid 11 has a relatively long molecular chain and may deform when subjected to thermal shock. However, second filler 13 forms covalent crosslinks with the molecules of the colloid material, making the colloid less susceptible to deformation during thermal shock, thereby enhancing the deformation resistance of encapsulation layer 10. First filler 12 and second filler 13 are hydrophobic materials that do not absorb moisture and have a water-repellent effect. When water vapor invades the colloid, it is blocked by first filler 12 and second filler 13, lengthening the water vapor invasion path. This, to a certain extent, blocks the invasion of water vapor and increases its difficulty. Furthermore, first filler 12 and second filler 14 can adjust the viscosity of colloid 11, facilitating the formation of a specific shape.

[0015] Preferably, in this embodiment, the main component of the colloid 11 is epoxy resin, and the main component of the first filler 12 and the second filler 13 is silicon dioxide. It has the advantages of being easy to obtain and having low manufacturing costs, and silicon dioxide has a high hardness, which can enhance the structural strength of the encapsulation layer 10. The colloid 11 can be selected from any one of bisphenol A epoxy colloid, aromatic epoxy colloid, alicyclic epoxy colloid, and modified epoxy colloid. In other embodiments, the main component of the colloid 11 can also be silicone resin. The first filler 12 is mixed with the epoxy resin to reduce the internal stress of the epoxy resin, and the second filler 13 can form covalent crosslinks with the epoxy group and the resin matrix, so that the colloid is not easily deformed when subjected to cold or hot shocks, thereby enhancing the anti-deformation ability of the encapsulation layer 10.

[0016] Preferably, within a unit volume, the weight proportion of the first filler 12 is 3%-15%, and the weight proportion of the second filler 13 is 15%-35%.

[0017] In one embodiment, the first filler 12 is in the shape of a solid sphere or ellipsoid, and its particle size ranges from 1 μm to 8 μm, preferably from -μm1 to 2 μm.

[0018] In one embodiment, the maximum diameter of the second filler 13 is in the range of 5 μm to 20 μm, preferably 5 μm to 12 μm.

[0019] In one embodiment, the sizes of the first fillers 12 are different and randomly distributed within a certain range; the sizes of the second fillers 13 are different and randomly distributed within a certain range. Figure 1a and Figure 1b Since the second filler is in sheet form, its outer contour is a polygonal shape, and its posture in the glue is not fixed, it will appear as a straight line when observed at certain angles.

[0020] The above encapsulation layer structure mixes the first filler and the second filler in the colloid, and the first filler and the second filler have different forms to form a composite material, which can extend the path for water vapor to invade the encapsulation layer and increase the airtightness of the encapsulation layer 10. The colloid is preferably an epoxy resin colloid.

[0021] In other embodiments, reference Figure 1b In the illustrated embodiment, the encapsulation layer 10' further contains a light-conversion material 14. This light-conversion material 14, which can be a phosphor or quantum dot powder, is used to convert the wavelength of light emitted by the LED chip, thereby changing the color of the light. The excellent airtightness of the encapsulation layer 10' reduces the risk of water vapor intrusion into the light-conversion material 14. Example 2

[0022] refer to Figure 2a and Figure 2b In the embodiment shown, this embodiment provides an LED package 100a, comprising a carrier 31, an LED chip 21 and the packaging layer 10' described in the above embodiment 1. The LED chip 21 is mounted on the carrier 31, and the packaging layer 10' covers the LED chip 21. The side and top surfaces of the LED chip 21 are not blocked by any other components except for being covered by the packaging layer 10'. The carrier 31 comprises a substrate 31b and a circuit layer 31a coated on the surface of the substrate 31b. The two electrode pads of the LED chip 21 are respectively connected to the circuit layer. The circuit layer 31a extends from the front of the carrier 31 to the side and back. In this embodiment, the structure of the packaging layer 10' is as follows: Figure 1bIn the embodiment shown, the light conversion material 14 is contained therein. In this embodiment, the light conversion material 14 comprises red and green phosphors. The LED chip 21 is a blue LED light emitting chip. The blue light emitted by the blue LED chip excites the phosphors, producing red and green light. The blue light then mixes to form white light.

[0023] Since the side surfaces and top surface of the LED chip 21 are covered by the packaging layer 10 ′ and are not blocked by any other components, the four side surfaces and top surface of the LED package 100 a can all emit light, resulting in good light extraction efficiency.

[0024] The encapsulation layer 10 ′ has the function of extending the water vapor intrusion path, thereby extending the service life of the LED chip 21 .

[0025] Preferably, in order to achieve better airtightness, the thickness of the packaging layer is at least greater than 180 μm. The thickness here refers to the vertical distance from the surface of the LED chip 21 to any point on the outer surface of the packaging layer 10 ′.

[0026] The packaging layer 10 ′ contains a first granular filler, which also has the function of scattering light, making the light emitted by the LED package 100 a softer.

[0027] In this embodiment, the substrate 31b may be a ceramic substrate, which has the advantage of good heat dissipation.

[0028] Due to the presence of the first filler and the second filler, the plasticity of the encapsulation layer 10' is improved. In this embodiment, the encapsulation layer 10a' forms a cube shape on the LED surface. In other embodiments, the encapsulation layer 10a' can also form a hemispherical shape, a capsule shape, or other shapes. Example 3

[0029] refer to Figure 3a and Figure 3b As shown, this embodiment provides an LED package 100b, including a carrier 32, an LED chip 21 and the packaging layer 10' described in the above embodiment 1. The carrier 32 is provided with a recess 32c for mounting the LED chip, the LED chip is mounted in the recess 32c, and the packaging layer 10' fills the recess 32c and covers the LED chip 21. In this embodiment, the carrier 32 includes a metal substrate 32b and a resin shell 32a arranged on the metal substrate 32b. The resin shell 32a is provided with a recess 32c for mounting the LED chip 21. A portion of the metal substrate 32b is exposed at the bottom of the recess 32c to form positive and negative electrode pads; the two electrode pads of the LED chip 21 are electrically connected to the positive and negative electrode pads, respectively. Both the positive electrode pad and the negative electrode pad are exposed on the back of the carrier 32. In this embodiment, the structure of the packaging layer 10' is as shown Figure 1bIn the embodiment shown, the light conversion material 14 is contained therein. In this embodiment, the light conversion material 14 comprises red and green phosphors. The LED chip 21 is a blue LED light emitting chip. The blue light emitted by the blue LED chip excites the phosphors, producing red and green light. The blue light then mixes to form white light.

[0030] In this embodiment, the resin housing 32a is made of a white, opaque resin material. Because the sides of the LED chip 21 are not only covered by the encapsulation layer 10' but also blocked by the resin housing 32a, only the top surface of the LED package 100b can emit light. In other embodiments, the resin housing 32a can be made of a transparent material to allow the side surfaces of the LED package 100b to emit light.

[0031] Preferably, in order to achieve better airtightness, the thickness of the packaging layer is at least greater than 180 μm. The thickness here refers to the vertical distance from the surface of the LED chip 21 to any point on the outer surface of the packaging layer 10 ′.

[0032] The encapsulation layer 10 ′ has the function of extending the water vapor intrusion path, thereby extending the service life of the LED chip 21 .

[0033] The packaging layer 10 ′ contains a first granular filler, which also has the function of scattering light, making the light emitted by the LED package 100 b softer.

[0034] Due to the presence of the first filler and the second filler, the plasticity of the encapsulation layer 10' is improved. In this embodiment, the encapsulation layer 10a' forms a plane on the LED surface. In other embodiments, the encapsulation layer 10a' can also protrude from the LED package 100b to form, for example, a hemispherical shape, a capsule shape, or other shapes. Example 4

[0035] refer to Figure 4a and Figure 4b As shown, this embodiment provides an LED screen 200, comprising a circuit board 33, a plurality of LED chips 22, 23, 24, and the encapsulation layer 10 described in the first embodiment. The plurality of LED chips 22, 23, 24 are soldered to the circuit board 33, and the encapsulation layer 10 covers each light-emitting unit 22, 23, 24 and the circuit board 33. In this embodiment, the plurality of LED chips 22, 23, 24 are respectively a red LED chip 22, a green LED chip 23, and a blue LED chip 24. The three LED chips together form a pixel unit 20, so that the LED screen 200 can be used to display patterns. In other embodiments, the pixel unit 20 can also be composed of four LED chips.

[0036] Because the three LED chips can display different shades of blue, encapsulation layer 10 does not need to contain phosphor. Encapsulation layer 10 reduces the path for water vapor intrusion, thereby extending the service life of LED chips 22, 23, and 24. Furthermore, encapsulation layer 10 contains a first filler that disperses light, facilitating light mixing and making the light emitted by LED screen 200 softer.

[0037] Preferably, in order to achieve better airtightness, the thickness of the packaging layer is at least greater than 180 μm. The thickness here refers to the straight-line distance from any point on the outer surface of the packaging layer 10 ′ to any point on the surface of the LED chip 21 .

[0038] In this embodiment, the circuit board 33 is a hard PCB. In other embodiments, the circuit board 33 is a glass substrate with a circuit disposed on the surface of the glass substrate. In other embodiments, the circuit board 33 is a flexible PCB.

[0039] It should be understood that the application of the present invention is not limited to the above examples. For those skilled in the art, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. An encapsulation layer, characterized in that: The invention comprises a colloid, a first filler and a second filler; the first filler and the second filler are uniformly mixed in the colloid; the first filler is granular and the second filler is flake; the first filler and the second filler are both hydrophobic and light-transmitting inorganic materials, and the colloid is a light-transmitting colloid.

2. The encapsulation layer according to claim 1, characterized in that: The main component of the colloid is epoxy resin, and the main components of the first filler and the second filler are silicon dioxide.

3. The encapsulation layer according to claim 1, wherein: Within a unit volume, the weight proportion of the first filler is 3%-15%, and the weight proportion of the second filler is 15%-35%.

4. The encapsulation layer according to claim 1, wherein: The first filler is spherical or ellipsoidal, and its particle size ranges from 1 μm to 8 μm.

5. The encapsulation layer according to claim 1, wherein: The maximum diameter of the second filler is in the range of 5 μm to 20 μm.

6. The encapsulation layer according to claim 1, wherein: The sizes of the first fillers are different and randomly distributed within a certain range; the sizes of the second fillers are different and randomly distributed within a certain range.

7. The encapsulation layer according to claim 1, wherein: The encapsulation layer also contains light conversion material.

8. An LED package, characterized in that: The LED chip comprises a carrier, an LED chip and the packaging layer according to claim 1, wherein the LED chip is mounted on the carrier, the packaging layer covers the LED chip, and the side and top surfaces of the LED chip are covered by the packaging layer without being blocked by any other components.

9. An LED package, characterized in that: The device comprises a carrier, an LED chip and the packaging layer according to claim 1, wherein the carrier is provided with a recess for mounting the LED chip, the LED chip is mounted in the recess, and the packaging layer fills the recess and covers the LED chip.

10. An LED screen, characterized in that: It comprises a circuit board, a plurality of LED chips and the packaging layer according to claim 1; the plurality of LED chips are soldered on the circuit board, and the packaging layer covers each of the light-emitting units and the circuit board.

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