A dual-color LED and its manufacturing process

Abstract

A dual-color LED and its manufacturing process include a substrate, an LED chip disposed in a die-bonding area of ​​the substrate, and a cofferdam disposed around the die-bonding area. The LED chip includes a first LED chip and a second LED chip. The top light-emitting surface of the first LED chip is provided with a first transparent adhesive layer and a first phosphor layer to form a first color temperature LED. The top light-emitting surface of the second LED chip is provided with a second phosphor layer to form a second color temperature LED. The height of the first phosphor layer plus the first transparent adhesive layer is the same as the height of the second phosphor layer. A phosphor adhesive layer is disposed on the side of the LED chip within the cofferdam, covering the side light-emitting surface of the LED chip. A second transparent adhesive layer is disposed within the cofferdam, covering the first color temperature LED, the second color temperature LED, and the phosphor adhesive layer. The height of the first phosphor layer plus the first transparent adhesive layer is the same as the height of the second phosphor layer, ensuring that the light spots of the first color temperature LED and the second color temperature LED are consistent and the light output is uniform.

Description

Technical Field

[0001] The present invention relates to the field of LEDs, and in particular to a dual-color LED and a manufacturing process thereof. Background Art

[0002] Traditional two-color COBs typically consist of a substrate, a first LED chip, and a second LED chip. The light-emitting surface of the first LED chip is coated with a first fluorescent adhesive, while the light-emitting surface of the second LED chip is coated with a second fluorescent adhesive. The varying thicknesses of the first and second fluorescent adhesives produce warm and cool color temperatures. This difference in fluorescent adhesive thickness results in inconsistent light spots, affecting light uniformity. Furthermore, the fluorescent adhesive layers are formed through a dispensing process. If the spacing between adjacent LED chips is small, the fluorescent adhesive can easily contact adjacent chips, making it unsuitable for densely integrated two-color COBs. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a dual-color LED and a manufacturing process thereof, which has better light uniformity and can use a dual-color COB with high-density die bonding.

[0004] In order to solve the above technical problems, the technical solution of the present invention is: a two-color LED, including a substrate, an LED chip arranged in the solid crystal area of ​​the substrate and a cofferdam arranged around the solid crystal area, the LED chip including a first LED chip and a second LED chip; the top light-emitting surface of the first LED chip is provided with a first transparent adhesive layer and a first phosphor layer to form a first color temperature LED, the top light-emitting surface of the second LED chip is provided with a second phosphor layer to form a second color temperature LED, the height of the first phosphor layer plus the first transparent adhesive layer is the same as the height of the second phosphor layer; a fluorescent adhesive layer is provided on the side of the LED chip in the cofferdam, the fluorescent adhesive layer covers the side light-emitting surface of the LED chip, and a second transparent adhesive layer covering the first color temperature LED, the second color temperature LED and the fluorescent adhesive layer is provided in the cofferdam. The present invention forms a phosphor layer on the top light-emitting surface of the LED chip by a powder spraying method, which can effectively control the thickness and range of the phosphor layer, ensure that the phosphors of LEDs with different color temperatures do not interfere with each other, and can be used for high-density solid-crystal COB with smaller LED chip spacing to form a two-color package; the powder amount of the phosphor layer formed by the powder spraying process is accurately controlled, the first transparent adhesive layer and the first phosphor layer are combined to form a light distribution structure of the first LED chip, and the second phosphor layer forms a light distribution structure of the second LED chip. The height of the first phosphor layer plus the first transparent adhesive layer is the same as the height of the second phosphor layer, so that the light spots of the first color temperature LED and the second color temperature LED are consistent and the light output is uniform.

[0005] As an improvement, the first LED chip and the second LED chip are both blue light flip chips.

[0006] As an improvement, the fluorescent glue layer is formed by fluorescent glue having a powder glue concentration in the range of 80-90%.

[0007] As an improvement, the top surface of the second transparent adhesive layer is flush with the top surface of the cofferdam.

[0008] As an improvement, the thickness of the first phosphor layer is 50-70 um, the thickness of the second phosphor layer is 70-100 um, the height of the phosphor glue layer is 110-130 um, and the distance between the first LED chip and the second LED chip is 0.30-0.35 mm.

[0009] As an improvement, the first phosphor layer and the second phosphor layer are in the shape of an arc with a convex center, and the center of the phosphor glue layer between the first LED chip and the second LED chip is concave.

[0010] The manufacturing process of the present invention:

[0011] (1) Solidify the crystal in the solid crystal area of ​​the substrate;

[0012] (2) Apply a first transparent adhesive to the top light-emitting surface of the first LED chip;

[0013] (3) Spraying a second phosphor on the top light-emitting surface of the second LED chip;

[0014] (4) forming a dam on the substrate to surround the solid crystal area;

[0015] (5) Fill the cofferdam with fluorescent glue;

[0016] (6) Spraying the first fluorescent powder on the first transparent adhesive;

[0017] (7) Fill the cofferdam with a second layer of transparent glue;

[0018] (8) Centrifugal sedimentation.

[0019] The beneficial effects brought about by the present invention compared with the prior art are:

[0020] The present invention forms a phosphor layer on the top light-emitting surface of the LED chip by a powder spraying method, which can effectively control the thickness and range of the phosphor layer, ensure that the phosphors of LEDs with different color temperatures do not interfere with each other, and can be used for high-density solid-crystal COB with smaller LED chip spacing to form a two-color package; the powder amount of the phosphor layer formed by the powder spraying process is accurately controlled, the first transparent adhesive layer and the first phosphor layer are combined to form a light distribution structure of the first LED chip, and the second phosphor layer forms a light distribution structure of the second LED chip. The height of the first phosphor layer plus the first transparent adhesive layer is the same as the height of the second phosphor layer, so that the light spots of the first color temperature LED and the second color temperature LED are consistent and the light output is uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the packaging of the present invention.

[0022] Figure 2 A process flow chart is produced for the present invention. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] like Figure 1 As shown, a bi-color LED comprises a substrate 1, LED chips disposed in the die-bonding area of ​​the substrate 1, and a cofferdam 2 disposed around the die-bonding area. The LED chips include a first LED chip 3 and a second LED chip 4, both of which are blue flip-chips. The first LED chip 3 and the second LED chip 4 are arranged in an alternating pattern within the cofferdam 2, with the spacing between the first LED chip 3 and the second LED chip 4 being 0.30-0.35 mm. The top light-emitting surface of the first LED chip 3 is provided with a first transparent adhesive layer 5, and the first phosphor layer 6 is provided on the first transparent adhesive layer 5. The first LED chip 3, the first transparent adhesive layer 5 and the first phosphor layer 6 constitute a first color temperature LED. The first color temperature LED in this embodiment is a cold color temperature LED; the top light-emitting surface of the second LED chip 4 is provided with a second phosphor layer 7 to form a second color temperature LED. The second color temperature LED in this embodiment is a warm color temperature LED; the first phosphor layer 6 and the second phosphor layer 7 are shaped like an arc with a convex middle. The thickness of the first phosphor layer 6 is 50-70um, and the thickness of the second phosphor layer 7 is 70-100um. The height of the first phosphor layer 6 plus the first transparent adhesive layer 5 is the same as the height of the second phosphor layer 7. A fluorescent adhesive layer 8 is provided within the cofferdam 2 on the side of the LED chip. This fluorescent adhesive layer 8 covers the side light-emitting surface of the LED chip. This fluorescent adhesive layer 8 is formed using fluorescent adhesive with a powder adhesive concentration in the range of 80-90%. The height of this fluorescent adhesive layer 8 is 110-130 μm, and the center of the fluorescent adhesive layer 8 between the first LED chip 3 and the second LED chip 4 is concave. A second transparent adhesive layer 9 is provided within the cofferdam 2, covering the first color temperature LED, the second color temperature LED, and the fluorescent adhesive layer 8. The top surface of this second transparent adhesive layer 9 is flush with the top surface of the cofferdam 2.

[0025] like Figure 2 As shown, the manufacturing process of the dual-color LED of the present invention includes the following steps:

[0026] (1) bonding the crystal in the crystal bonding area of ​​the substrate 1;

[0027] (2) Apply a first transparent adhesive to the top light-emitting surface of the first LED chip 3;

[0028] (3) Spraying a second phosphor on the top light-emitting surface of the second LED chip 4;

[0029] (4) forming a cofferdam 2 on the substrate 1 to surround the crystal bonding area;

[0030] (5) Fill the cofferdam 2 with fluorescent glue. The concentration of the fluorescent glue powder is controlled within the range of 80-90%. Use a precision glue dispenser to dispense glue between the two LED chips.

[0031] (6) Spraying the first fluorescent powder on the first transparent adhesive;

[0032] (7) Fill the cofferdam 2 with a second transparent glue;

[0033] (8) Centrifugal sedimentation;

[0034] (9) Splitting boards and light;

[0035] (10) Packaging.

[0036] The present invention forms a phosphor layer on the top light-emitting surface of the LED chip by powder spraying, which can effectively control the thickness and range of the phosphor layer, ensure that the phosphors of LEDs with different color temperatures do not interfere with each other, and can be used for high-density solid-crystal COB with smaller LED chip spacing to form a two-color package; the powder amount of the phosphor layer formed by the powder spraying process is precisely controlled, the first transparent adhesive layer 5 and the first phosphor layer 6 are combined to form a light distribution structure of the first LED chip 3, and the second phosphor layer 7 forms a light distribution structure of the second LED chip 4. The height of the first phosphor layer 6 plus the first transparent adhesive layer 5 is the same as the height of the second phosphor layer 7, so that the light spots of the first color temperature LED and the second color temperature LED are consistent and the light output is uniform.

Claims

1. A two-color LED comprising a substrate, an LED chip disposed in a die-bonding region of the substrate, and a dam disposed around the die-bonding region, wherein the LED chip comprises a first LED chip and a second LED chip; characterized in that: The top light-emitting surface of the first LED chip is provided with a first transparent adhesive layer and a first phosphor layer to form a first color temperature LED, and the top light-emitting surface of the second LED chip is provided with a second phosphor layer to form a second color temperature LED, and the height of the first phosphor layer plus the first transparent adhesive layer is the same as the height of the second phosphor layer; a fluorescent adhesive layer is provided on the side of the LED chip in the cofferdam, and the fluorescent adhesive layer covers the side light-emitting surface of the LED chip, and a second transparent adhesive layer covering the first color temperature LED, the second color temperature LED and the fluorescent adhesive layer is provided in the cofferdam; the thickness of the first phosphor layer is 50-70um, the thickness of the second phosphor layer is 70-100um, the height of the fluorescent adhesive layer is 110-130um, and the spacing between the first LED chip and the second LED chip is 0.30-0.35mm.

2. A dual-color LED according to claim 1, characterized in that: The first LED chip and the second LED chip are both blue light flip chips.

3. The dual-color LED according to claim 1, characterized in that: The fluorescent glue layer is formed by fluorescent glue having a powder glue concentration in the range of 80-90%.

4. The dual-color LED according to claim 1, characterized in that: The top surface of the second transparent adhesive layer is flush with the top surface of the cofferdam.

5. The dual-color LED according to claim 1, characterized in that: The first phosphor layer and the second phosphor layer are in an arc shape with a convex center, and the center of the phosphor glue layer between the first LED chip and the second LED chip is concave.

6. A process for manufacturing a dual-color LED as claimed in claim 1, characterized in that: The following steps are involved: (1) Solidify the crystal in the solid crystal area of ​​the substrate; (2) Apply a first transparent adhesive to the top light-emitting surface of the first LED chip; (3) Spraying a second phosphor on the top light-emitting surface of the second LED chip; (4) forming a dam on the substrate to surround the solid crystal area; (5) Fill the cofferdam with fluorescent glue; (6) Spraying the first fluorescent powder on the first transparent adhesive; (7) Fill the cofferdam with a second layer of transparent glue; (8) Centrifugal sedimentation.

7. The process for manufacturing a dual-color LED according to claim 6, characterized in that: In the step (5), the concentration of the fluorescent glue powder is controlled within the range of 80-90%, and a precision glue dispenser is used to dispense glue at the interval between the two LED chips.

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