LED packaging structure and manufacturing method

Abstract

The invention discloses an LED packaging structure and a manufacturing method. The LED packaging structure comprises a support, an LED chip, a first reflecting layer, a second reflecting layer and a light conversion layer. The support is provided with a plurality of die bonding areas. The LED chip is fixed on the die bonding area through the solder paste layer and is electrically connected with the bracket; the first reflecting layer is arranged on the bracket, and the height of the first reflecting layer is not higher than the bottom of the LED chip; the second reflecting layer is arranged on the first reflecting layer, and a set distance is kept between the second reflecting layer and the LED chip; the light conversion layer is arranged on the support and covers the LED chip, the first reflection layer and the second reflection layer. According to the LED packaging structure provided by the invention, the light emitting efficiency of the LED chip can be improved. According to the manufacturing method of the LED packaging structure, the manufacturing difficulty of the novel LED packaging structure can be reduced, and the manufacturing efficiency of the novel LED packaging structure can be improved.

Description

Technical Field

[0001] This invention belongs to the field of LED technology, specifically relating to an LED packaging structure and its manufacturing method. Background Technology

[0002] With the continuous expansion and deepening of market applications, downstream industries have placed higher and more urgent demands on the brightness performance of LED packaging structures. In the increasingly fierce market competition, improving the brightness of LED packaging structures has become crucial for seizing technological advantages. Therefore, how to further explore and improve the luminous efficiency of LED packaging structures has become a core technical challenge focusing on both industry and academia. Existing LED packaging structures have design shortcomings: (1) The solder paste overflowing around the LED chip and the solder beads under the LED chip cannot be effectively blocked, and will inevitably absorb some of the light emitted by the LED chip; (2) The single-layer reflective material coated around the LED chip has uncontrollable fluidity and is easy to flow to the side of the LED chip. Due to the existence of surface tension, the reflective material will climb to the side of the LED chip under the action of surface tension, thereby blocking the light output from the side of the LED chip and reducing the overall light output efficiency of the LED packaging structure.

[0003] Currently, it is necessary to develop a new LED packaging structure to improve the light extraction efficiency of LED chips; it is also necessary to develop a manufacturing method for the LED packaging structure to reduce the manufacturing difficulty of the new LED packaging structure and improve its manufacturing efficiency. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides an LED packaging structure that can improve the light extraction efficiency of LED chips.

[0005] The present invention adopts the following technical solution: An LED packaging structure includes a bracket, an LED chip, a first reflective layer, a second reflective layer, and a light conversion layer. The bracket has a plurality of die-bonding regions. The LED chip is fixed to the die-bonding regions via solder paste and electrically connected to the bracket. The first reflective layer is disposed on the bracket, and its height is not higher than the bottom of the LED chip. The second reflective layer is disposed on the first reflective layer, and the second reflective layer maintains a predetermined distance from the LED chip. The light conversion layer is disposed on the bracket and covers the LED chip, the first reflective layer, and the second reflective layer.

[0006] Furthermore, the support has an inner cavity; a plurality of die-bonding regions are provided at the bottom of the inner cavity.

[0007] Furthermore, the first reflective layer is a first white adhesive layer; the second reflective layer is a second white adhesive layer; the first white adhesive layer covers the bottom of the inner cavity, and the height of the first white adhesive layer is not higher than the bottom of the LED chip; the second white adhesive layer is disposed on the first white adhesive layer, and the second white adhesive layer maintains a set distance from the LED chip.

[0008] Furthermore, the second reflective layer is also disposed around the cup wall of the inner cavity to form a reflective arc surface.

[0009] Furthermore, the height of the first reflective layer is flush with the bottom of the LED chip.

[0010] Furthermore, at least two LED chips are provided; the portion of the second reflective layer located between the LED chips has a circular arc shape in cross-section.

[0011] Furthermore, the fluid viscosity of the first reflective layer is lower than that of the second reflective layer.

[0012] Furthermore, the fluid viscosity of the first reflective layer is less than 3000 MPa·s; the fluid viscosity of the second reflective layer is 3000 MPa·s to 10000 MPa·s.

[0013] Furthermore, the light conversion layer is a light conversion layer formed by mixing yellow phosphor and silicone; or, the light conversion layer is a light conversion layer formed by mixing yellow phosphor and red phosphor with silicone.

[0014] Another objective of this invention is to provide a method for manufacturing an LED packaging structure, thereby reducing the manufacturing difficulty of the novel LED packaging structure and improving its manufacturing efficiency.

[0015] A method for manufacturing an LED packaging structure, comprising the following steps: S1. Fabricate the support, and form the die-bonding region on the support; S2. Using solder paste, fix the LED chip onto the die bonded area; S3. The first reflective layer is placed on the bracket, and the height of the first reflective layer is not higher than the bottom of the LED chip; S4. The second reflective layer is disposed on the first reflective layer, and the second reflective layer and the LED chip are kept at a set distance. S5. The light conversion layer is disposed on the bracket, and the light conversion layer covers the LED chip, the first reflective layer and the second reflective layer.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention discloses an LED packaging structure, wherein a first reflective layer is disposed on a support, and its height is no higher than the bottom of the LED chip. The first reflective layer can cover the solder paste overflow portion under the LED chip and the solder beads under the LED, which can effectively prevent the solder paste overflow portion and the solder beads from absorbing the light emitted by the LED chip, thereby improving the light emission efficiency of the LED chip. A second reflective layer is disposed on the first reflective layer, and the second reflective layer maintains a set distance from the LED chip, which can effectively prevent the side of the LED chip from being blocked, thereby improving the light emission efficiency of the LED chip.

[0017] The present invention discloses a method for manufacturing an LED packaging structure, which has clearly defined steps. Through steps S1 to S5, the method can guide the step-by-step manufacturing of the novel LED packaging structure, reduce the manufacturing difficulty of the novel LED packaging structure, and improve the manufacturing efficiency of the novel LED packaging structure. Attached Figure Description

[0018] The technology of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Figure 1 This is a front cross-sectional view of the LED packaging structure; Figure 2 This is a schematic diagram (top view) showing the die-bonding area on the support. Figure 3 This is a schematic diagram (top view) showing an LED chip mounted on the die-bonding area. Figure 4 This is a schematic diagram (top view) showing the first reflective layer installed on the support. Figure 5 This is a schematic diagram (top view) showing the second reflective layer installed on the support. Figure 6 This is a schematic diagram (top view) of the light conversion layer installed on the support.

[0019] Figure label: 1-Stent; 11-Inner cavity; 2- LED chips; 3-First reflective layer; 4-Second reflective layer; A-Reflective arc surface; B-Spacing; 5-Light conversion layer; 6-Die-bonding region; 7- Solder paste layer. Detailed Implementation

[0020] The following will provide a clear and complete description of the concept, specific structure, and technical effects of the present invention in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, solution, and effects of the present invention. It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The same reference numerals used throughout the accompanying drawings indicate the same or similar parts.

[0021] It should be noted that, unless otherwise specified, when a feature is referred to as "fixed" or "connected" to another feature, it can be directly fixed or connected to the other feature, or indirectly fixed or connected to the other feature. Furthermore, the descriptions of "up," "down," "left," and "right" used in this invention are only relative to the relative positional relationships of the various components of the invention in the accompanying drawings.

[0022] Reference Figures 1 to 6 An LED packaging structure includes a bracket 1, an LED chip 2, a first reflective layer 3, a second reflective layer 4, and a light conversion layer 5. The bracket 1 has a plurality of die-bonding regions 6. The LED chip 2 is fixed to the die-bonding regions 6 via solder paste 7 and forms an electrical connection with the bracket 1. The first LED chip 2 is used to emit light. The first reflective layer 3 is disposed on the bracket 1, and the height of the first reflective layer 3 is not higher than the bottom of the LED chip 2. The first reflective layer 3 can be used to cover solder paste overflow and / or solder beads. The second reflective layer 4 is disposed on the first reflective layer 3, and the second reflective layer 4 maintains a set distance from the LED chip 2. The light conversion layer 5 is disposed on the bracket 1 and covers the LED chip 2, the first reflective layer 3, and the second reflective layer 4.

[0023] Reference Figure 1 In one embodiment, the height of the first reflective layer 3 is flush with the bottom of the LED chip 2; or, the height of the first reflective layer 3 is lower than the bottom of the LED chip 2; the first reflective layer 3 can be used to cover the solder paste overflow portion under the LED chip 2 (which is part of the solder paste layer 7) and can be used to cover the solder beads (which are attached to the LED chip 2) under the LED chip 2.

[0024] In one embodiment, the height of the first reflective layer 3 is 5µm to 70µm.

[0025] Reference Figures 1 to 6 In one embodiment, the LED chip 2 is a flip-chip LED chip.

[0026] Reference Figures 1 to 6 In one embodiment, the support 1 has an inner cavity 11; a plurality of die-bonding regions 6 are provided at the bottom of the inner cavity 11. Preferably, the inner cavity is a bowl-shaped cavity.

[0027] Reference Figures 1 to 6 In one embodiment, the LED chip 2 is provided with a plurality of chips; preferably, four LED chips 2 are provided in one of the inner cavities 11.

[0028] Reference Figures 1 to 6 In one embodiment, the first reflective layer 3 is a first white adhesive layer; the second reflective layer 4 is a second white adhesive layer; the first white adhesive layer covers the bottom of the inner cavity 11, and the height of the first white adhesive layer is not higher than the bottom of the LED chip 2; preferably, the height of the first white adhesive layer is flush with the bottom of the LED chip 2, the first white adhesive layer can cover the solder paste overflow portion under the LED chip 2 (which is part of the solder paste layer 7), and the first white adhesive layer can cover the solder beads under the LED chip 2 (the solder beads are present under the LED chip 2 and are not part of the solder paste layer); the second white adhesive layer is disposed on the first white adhesive layer, and the second white adhesive layer maintains a set distance B from the LED chip 2.

[0029] Reference Figure 1 and Figure 5 In one embodiment, the second reflective layer 4 (such as the second white adhesive layer) is also disposed around the cup wall of the inner cavity 11 to form a reflective arc surface A, which can improve the light extraction efficiency of the LED packaging structure.

[0030] In one embodiment, the fluidity of the first reflective layer 3 is higher than that of the second reflective layer 4. The fluidity of the first reflective layer 3 refers to its fluidity before curing; before curing, the first reflective layer 3 is a gel-like reflective material that requires baking to solidify and form the final product. Similarly, the fluidity of the second reflective layer 4 refers to its fluidity before curing; before curing, the second reflective layer 4 is a gel-like reflective material that requires baking to solidify and form the final product.

[0031] In one embodiment, the fluid viscosity of the first reflective layer 3 is lower than that of the second reflective layer 4. Preferably, the fluid viscosity of the first reflective layer 3 is less than 3000 MPa·s; the fluid viscosity of the second reflective layer 4 is 3000 MPa·s to 10000 MPa·s; where "MPa·s" is a unit of dynamic viscosity, "MPa" is megapascals, and "s" is seconds. The fluid viscosity of the first reflective layer 3 refers to its viscosity before curing. Before curing, the first reflective layer 3 is a gel-like reflective material that requires (baking) to cure and form the final product. Similarly, the fluid viscosity of the second reflective layer 4 refers to its viscosity before curing. Before curing, the second reflective layer 4 is a gel-like reflective material that requires (baking) to cure and form the final product. In one embodiment, a first reflective material (such as a first white glue) is applied to the bottom of the inner cavity 11 of the bracket 1, and the height of the first reflective material is not higher than the height of the bottom of the LED chip 2 (so that the first reflective material covers the solder paste overflow and solder beads under the LED chip 2). Then, the first reflective material is baked and cured to form the first reflective layer 3.

[0032] The second reflective material (such as the second white glue) is coated on the first reflective layer 3, and the second reflective material is kept at a set distance B from the LED chip 2 (such as the side away from the LED chip 2). The second reflective material is coated on the cup wall of the inner cavity 11 to form a reflective arc surface A. Then, the second reflective material is baked and cured to form the second reflective layer 4. The fluid viscosity of the first reflective material (such as the first white glue) is lower than that of the second reflective material (such as the second white glue); the fluidity of the first reflective material (such as the first white glue) is higher than that of the second reflective material (such as the second white glue); compared to the second reflective material, the first reflective material has lower fluid viscosity and higher fluidity, and the height of the first reflective material is not higher than the bottom of the LED chip, making it difficult for the first reflective material to adhere to the side of the LED chip 2 (the uncured first reflective material is relatively easy to fall when affected by gravity); compared to the first reflective material, the second reflective material has higher fluid viscosity and lower fluidity, and after the second reflective material is placed on the first reflective layer 3, the second reflective material is easy to adhere and is not easy to flow to the side of the LED chip.

[0033] Among them, after the first reflective layer 3 is cured and formed, the roughness of its upper surface is greater than the roughness of the bottom of the inner cavity 11. When the second reflective material is placed on the first reflective layer 3, it can effectively prevent the second reflective material from flowing to the LED chip, effectively prevent the side of the LED chip 2 from being blocked, and improve the light output efficiency. Combination Figure 1 and Figure 5 To understand this, after the second reflective layer 4 is fixed and formed, it is disposed on the first reflective layer 3, around the cup wall of the inner cavity 11 of the bracket 1, and in a "+" shape between the LED chips 2; preferably, the portion of the second reflective layer 4 between the LED chips 2 has an arc-shaped cross-section (such as a semi-circle); the cross-sectional shape of the portion of the second reflective layer 4 between the LED chips 2 is not limited to an arc shape, and can also be other shapes; the second reflective layer 4 is away from the side of the LED chip 2, which effectively avoids blocking the side of the LED chip and can effectively improve the light output efficiency of the LED chip 2.

[0034] In one embodiment, after the first white glue is baked and cured, a first white glue layer is formed; wherein, the basic composition of the first white glue includes a resin matrix and a functional filler; the resin matrix is ​​such as epoxy resin; the functional filler is such as a filler containing titanium dioxide and (nano-scale) aluminum oxide.

[0035] After the second white glue is baked and cured, the second white glue layer is formed; wherein, the basic composition of the second white glue includes a resin matrix and functional fillers; the resin matrix is ​​such as epoxy resin; the functional fillers are such as fillers containing titanium dioxide and (nano-scale) aluminum oxide.

[0036] In one embodiment, the present invention significantly improves the light extraction efficiency of the LED chip 2 through the layered design of the first reflective layer 3 and the second reflective layer 4. The first reflective layer 3 covers the "solder paste overflow portion and solder beads," effectively preventing the solder paste overflow portion and solder beads from absorbing the light emitted by the LED chip 2, thus improving the light extraction efficiency of the LED chip 2. The second reflective layer 4 is positioned away from the side of the LED chip, effectively avoiding shading of the side of the LED chip 2, further improving the light extraction efficiency of the LED chip 2. Simultaneously, the present invention also utilizes the second reflective layer 4 to form a reflective arc surface A at the inner wall of the cup 11 to enhance the light extraction efficiency.

[0037] Reference Figure 1 and Figure 6 In one embodiment, the light conversion layer 5 is a light conversion layer formed by mixing yellow phosphor and silicone; or, the light conversion layer 5 is a light conversion layer formed by mixing yellow phosphor and red phosphor with silicone.

[0038] Another objective of this invention is to provide a method for manufacturing an LED packaging structure, thereby reducing the manufacturing difficulty of the novel LED packaging structure and improving its manufacturing efficiency.

[0039] A method for manufacturing an LED packaging structure, comprising the following steps: S1. Fabricate the support 1, so that the die-bonding region 6 is formed on the support 1; S2. Using solder paste, the LED chip 2 is fixed on the die bonding area 6; wherein, the solder paste cures to form the solder paste layer 7; S3. The first reflective layer 3 is placed on the bracket 1, and the height of the first reflective layer 3 is not higher than the bottom of the LED chip 2 (purpose: to cover the solder paste overflow and solder beads under the LED chip 2 to improve the light output efficiency of the LED chip 2). S4. The second reflective layer 4 is disposed on the first reflective layer 3, and the second reflective layer 4 and the LED chip 2 are kept at a set distance B, and the second reflective layer 4 forms a reflective arc surface A at the cup wall of the inner cavity 11. S5. The light conversion layer 5 is disposed on the bracket 1, and the light conversion layer 5 covers the LED chip 2, the first reflective layer 3, and the second reflective layer 4. Specifically, a light conversion material (such as a mixture of yellow phosphor and silicone) is filled into the inner cavity 11 of the LED bracket 1, and the light conversion material covers the LED chip 2, the first reflective layer 3, and the second reflective layer 4. Then, the light conversion material is cured and shaped to finally form the light conversion layer 5.

[0040] Other aspects of the LED packaging structure and manufacturing method described in this invention can be found in the prior art and will not be repeated here.

[0041] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An LED packaging structure, characterized in that, The device includes a support, an LED chip, a first reflective layer, a second reflective layer, and a light conversion layer. The support has several die-bonding areas. The LED chip is fixed to the die-bonding areas via solder paste and electrically connected to the support. The first reflective layer is disposed on the support, and its height is no higher than the bottom of the LED chip. The second reflective layer is disposed on the first reflective layer, and maintains a predetermined distance from the LED chip. The light conversion layer is disposed on the support and covers the LED chip, the first reflective layer, and the second reflective layer.

2. The LED packaging structure according to claim 1, characterized in that, The support has an inner cavity; a plurality of die-bonding regions are provided at the bottom of the inner cavity.

3. The LED packaging structure according to claim 2, characterized in that, The first reflective layer is a first white adhesive layer; the second reflective layer is a second white adhesive layer; the first white adhesive layer covers the bottom of the inner cavity, and the height of the first white adhesive layer is not higher than the bottom of the LED chip; the second white adhesive layer is disposed on the first white adhesive layer, and the second white adhesive layer maintains a set distance from the LED chip.

4. The LED packaging structure according to claim 2, characterized in that, The second reflective layer is also disposed around the cup wall of the inner cavity to form a reflective arc surface.

5. The LED packaging structure according to claim 1, characterized in that, The height of the first reflective layer is flush with the bottom of the LED chip.

6. The LED packaging structure according to claim 1, characterized in that, The LED chip is provided with at least two chips; the second reflective layer is located between the LED chips, and its cross-sectional shape is arc-shaped.

7. The LED packaging structure according to claim 1, characterized in that, The fluid viscosity of the first reflective layer is lower than that of the second reflective layer.

8. The LED packaging structure according to claim 7, characterized in that, The fluid viscosity of the first reflective layer is less than 3000 MPa·s; the fluid viscosity of the second reflective layer is 3000 MPa·s to 10000 MPa·s.

9. An LED packaging structure according to any one of claims 1 to 8, characterized in that, The light conversion layer is a light conversion layer made of a mixture of yellow phosphor and silica gel; or, the light conversion layer is a light conversion layer made of a mixture of yellow phosphor, red phosphor and silica gel.

10. A method for manufacturing an LED packaging structure, used to manufacture an LED packaging structure according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Fabricate the support, and form the die-bonding region on the support; S2. Using solder paste, fix the LED chip onto the die bonded area; S3. The first reflective layer is placed on the bracket, and the height of the first reflective layer is not higher than the bottom of the LED chip; S4. The second reflective layer is disposed on the first reflective layer, and the second reflective layer and the LED chip are kept at a set distance. S5. The light conversion layer is disposed on the bracket, and the light conversion layer covers the LED chip, the first reflective layer and the second reflective layer.

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