A manufacturing process for a two-color LED

Abstract

A dual-color LED manufacturing process includes the following steps: (1) Fix a first LED chip and a second LED chip on the functional area of the substrate; (2) Dot a spherical transparent glue on the top light-emitting surface of the first LED chip, and dot a spherical first fluorescent glue on the top light-emitting surface of the second LED chip; (3) Bake; (4) Dot a second fluorescent glue on the first fluorescent glue; (5) Make the second fluorescent glue flow along the arc surface of the first fluorescent glue to the side light-emitting surface of the second LED chip through centrifugal motion; (6) Bake; (7) Build a cofferdam; (8) Fill a third fluorescent glue in the cofferdam, and the third fluorescent glue covers the transparent glue and the first fluorescent glue; (9) Let the third fluorescent glue settle naturally; (10) Bake to cure the third fluorescent glue. The second fluorescent glue flows to the spacing between adjacent chips by centrifugation, is used to excite the blue light around the chips, realizes a color temperature of 1600 - 8000K, and the chips can be integrated with high density.

Description

Technical Field

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

[0002] Dual-color LEDs achieve color temperature control through the ratio of fluorescent gels with different color temperatures. For example, a manufacturing process for a dual-color LED as described in claim 1 of Chinese Patent Publication No. CN114220801A includes the following steps: (1) Fixing the chips on the die bonding area of the substrate; (2) Applying a first transparent gel on the light-emitting surface of the top surface of the first LED chip; (3) Spraying a second fluorescent powder on the light-emitting surface of the top surface of the second LED chip; (4) Forming a retaining wall on the substrate to surround the die bonding area; (5) Filling a fluorescent gel within the retaining wall; (6) Spraying a first fluorescent powder on the first transparent gel; (7) Filling a second transparent gel within the retaining wall; (8) Centrifugal sedimentation. The fluorescent gel layer formed by spraying powder on the top surface of the second LED chip is usually relatively flat, the light emission is not concentrated enough, and the brightness of the light emission is also relatively low, which needs to be improved. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a manufacturing process for dual-color LEDs with higher brightness, higher light emission concentration, and capable of achieving high-density integration of LED chips.

[0004] To solve the above technical problem, the technical solution of the present invention is: A manufacturing process for dual-color LEDs, including the following steps:

[0005] (1) Fixing a first LED chip and a second LED chip in the functional area of the substrate;

[0006] (2) Applying a spherical transparent gel on the light-emitting surface of the top surface of the first LED chip, and applying a spherical first fluorescent gel on the light-emitting surface of the top surface of the second LED chip;

[0007] (3) Baking and curing the transparent gel and the first fluorescent gel;

[0008] (4) Applying a second fluorescent gel on the first fluorescent gel;

[0009] (5) Making the second fluorescent gel flow along the arc surface of the first fluorescent gel to the side light-emitting surface of the second LED chip through centrifugal motion;

[0010] (6) Baking and curing the second fluorescent gel;

[0011] (7) Making a retaining wall around the functional area on the substrate;

[0012] (8) Filling a third fluorescent gel within the retaining wall, and the third fluorescent gel covers the transparent gel and the first fluorescent gel;

[0013] (9) Natural sedimentation of the third fluorescent gel;

[0014] (10) Bake to cure the third fluorescent glue.

[0015] In the present invention, a spherical first fluorescent glue is formed on the top surface of the second LED chip by dispensing, and a spherical transparent glue is formed on the top surface of the first LED chip by dispensing. The spherical design has a certain light-concentrating function, higher light-emitting concentration, and higher light-emitting brightness. The second fluorescent glue flows to the spacing between adjacent chips by centrifugation to excite the blue light around the chips, achieving a color temperature of 1600 - 8000K, and the chips can be integrated at a high density.

[0016] As an improvement, several rows of LED chips are provided in the functional area of the substrate. Each row of LED chips includes a first LED chip group and a second LED chip group arranged left and right. The first LED chip group is composed of more than one first LED chip arranged in a line, and the second LED chip group is composed of more than one second LED chip arranged in a line.

[0017] As an improvement, in the same row of LED chips, the number of first LED chips in the first LED chip group is the same as the number of second LED chips in the second LED chip group.

[0018] As an improvement, the height of the transparent glue is 330 - 350um, and the amount of glue used for dispensing the transparent glue is 0.08 - 0.12ul.

[0019] As an improvement, the concentration of the first fluorescent glue is 70 - 75%, and the powder-to-glue ratio is 240 - 250%; the concentration of the second fluorescent glue is 70 - 80%, and the powder-to-glue ratio is 340 - 350%; the concentration of the third fluorescent glue is 12 - 16%, and the powder-to-glue ratio is 130 - 140%.

[0020] As an improvement, in step (2), first apply a thin layer of transparent glue on the light-emitting surface of the top surface of the second LED chip, and then dispense the first fluorescent glue on the thin transparent glue.

[0021] As an improvement, when dispensing the transparent glue on the first LED chip, the dispensing head first discharges glue directly above the first LED chip to form a glue droplet; then the dispensing head moves vertically downward with the glue droplet to the top surface of the first LED chip; after the glue droplet is transferred to the top surface of the first LED chip, the dispensing head leaves vertically to complete the dispensing of the transparent glue.

[0022] As an improvement, the first LED chip and the second LED chip are blue light flip chips.

[0023] The beneficial effects brought by the present invention compared with the prior art are:

[0024] In the present invention, a spherical first fluorescent glue is formed on the top surface of the second LED chip by means of dispensing, and a spherical transparent glue is formed on the top surface of the first LED chip by means of dispensing. The spherical design has a certain light condensing function, with higher light output concentration and higher light output brightness. The second fluorescent glue flows to the spacing between adjacent chips by means of centrifugation to excite the blue light around the chips, achieving a color temperature of 1600 - 8000K, and the chips can be integrated at a high density. Description of the Drawings

[0025] Figure 1 It is a top view of the COB.

[0026] Figure 2 It is a cross-sectional view of the COB.

[0027] Figure 3 It is a manufacturing flow chart of the present invention.

[0028] Figure 4 It is a schematic diagram of the second LED chip. Detailed Embodiment

[0029] The present invention will be further described below in conjunction with the drawings in the specification.

[0030] As Figure 2 、 3 shown, a dual-color LED manufacturing process includes the following steps:

[0031] (1) Fix the first LED chip 1 and the second LED chip 2 in the functional area of the substrate;

[0032] (2) Dispense a spherical transparent glue 4 on the light-emitting surface of the top surface of the first LED chip 1, i.e., the cold white color temperature LED chip, and dispense a spherical first fluorescent glue 5 on the light-emitting surface of the top surface of the second LED chip 2, i.e., the warm white color temperature chip;

[0033] (3) Bake and cure the transparent glue 4 and the first fluorescent glue 5;

[0034] (4) Dispense the second fluorescent glue 6 on the first fluorescent glue 5;

[0035] (5) Make the second fluorescent glue 6 flow along the arc surface of the first fluorescent glue 5 to the side light-emitting surface of the second LED chip 2 by means of centrifugal motion;

[0036] (6) Bake and cure the second fluorescent glue 6;

[0037] (7) Make a cofferdam 3 around the functional area on the substrate;

[0038] (8) Fill the third fluorescent glue 7 in the cofferdam 3, and the third fluorescent glue 7 covers the transparent glue 4 and the first fluorescent glue 5;

[0039] (9) The third fluorescent glue 7 settles naturally;

[0040] (10) Bake to cure the third fluorescent glue 7.

[0041] (11) Separate the board and perform spectral separation;

[0042] (12) Package.

[0043] The first LED chip 1 and the second LED chip 2 are blue light flip chips.

[0044] As Figure 1 、 2 shown, several rows of LED chips arranged in parallel are provided in the functional area of the substrate. The number of LED chips in each row is different, and the number of LED chips in each row gradually increases from the edge to the middle; each row of LED chips includes a first LED chip group and a second LED chip group arranged left and right. The first LED chip group is composed of more than one first LED chip 1 arranged in a line, and the second LED chip group is composed of more than one second LED chip 2 arranged in a line. In the same row of LED chips, the number of the first LED chips 1 in the first LED chip group is the same as the number of the second LED chips 2 in the second LED chip group. The two-color temperature light-emitting areas of each row of LEDs are arranged left and right, and the two-color temperature light-emitting areas of adjacent rows are arranged at intervals, which can solve the defect that there is only one kind of color temperature light-emitting area at the edge of the COB, and the two color temperatures are mixed more evenly.

[0045] The amount of glue used for dotting the transparent glue 4 is 0.08 - 0.12 ul, and the height of the spherical transparent glue formed is 330 - 350 um.

[0046] The concentration of the first fluorescent glue 5 is 70 - 75%, the powder-to-glue ratio is 240 - 250%, and the color temperature is 5000K; the concentration of the second fluorescent glue 6 is 70 - 80%, the powder-to-glue ratio is 340 - 350%, and the color temperature is 1700K; the concentration of the third fluorescent glue 7 is 12 - 16%, the powder-to-glue ratio is 130 - 140%, and the color temperature is 8000K.

[0047] As Figure 4 shown, in the step (2), first apply a thin transparent glue 8 on the light-emitting surface of the top of the second LED chip 2, and then dot the first fluorescent glue 5 on the thin transparent glue 8. The thin transparent glue layer does not affect the light emission of the LED, and can increase the viscosity, making the combination of the first fluorescent glue 5 and the second LED chip 2 more reliable.

[0048] When applying transparent glue on the first LED chip 1, the dispensing head first ejects glue directly above the first LED chip 1 to form a glue droplet; then the dispensing head moves vertically downward with the glue droplet to the top surface of the first LED chip 1; after the glue droplet is transferred to the top surface of the first LED chip 1, the dispensing head leaves vertically, completing the dispensing of the transparent glue. The dispensing method of the present invention can form a ball head shape with a better shape, and the dispensing head will not carry glue when it detaches.

Claims

1. A dual-color LED manufacturing process, characterized in that, It includes the following steps: (1) Fix the first LED chip and the second LED chip on the functional area of the substrate; (2) Dot a spherical transparent glue on the top light-emitting surface of the first LED chip, and dot a spherical first fluorescent glue on the top light-emitting surface of the second LED chip; (3) Bake and cure the transparent glue and the first fluorescent glue; (4) Dot the second fluorescent glue on the first fluorescent glue; (5) Make the second fluorescent glue flow along the arc surface of the first fluorescent glue to the side light-emitting surface of the second LED chip through centrifugal motion; (6) Bake and cure the second fluorescent glue; (7) Make a cofferdam around the functional area on the substrate; (8) Fill the third fluorescent glue in the cofferdam, and the third fluorescent glue covers the transparent glue and the first fluorescent glue; (9) Let the third fluorescent glue settle naturally; (10) Bake to cure the third fluorescent glue.

2. The manufacturing process of a two-color LED according to claim 1, wherein: Several rows of LED chips are provided in the functional area of the substrate. Each row of LED chips includes a first LED chip group and a second LED chip group arranged left and right. The first LED chip group is composed of more than one first LED chip arranged in a line, and the second LED chip group is composed of more than one second LED chip arranged in a line.

3. The manufacturing process of a two-color LED according to claim 2, characterized in that: In the same row of LED chips, the number of first LED chips in the first LED chip group is the same as the number of second LED chips in the second LED chip group.

4. A dual-color LED manufacturing process according to claim 1, characterized in that: The height of the transparent glue is 330 - 350um, and the amount of glue used for dotting the transparent glue is 0.08 - 0.12ul.

5. A dual-color LED manufacturing process according to claim 1, characterized in that: The concentration of the first fluorescent glue is 70 - 75%, and the powder-to-glue ratio is 240 - 250%; the concentration of the second fluorescent glue is 70 - 80%, and the powder-to-glue ratio is 340 - 350%; the concentration of the third fluorescent glue is 12 - 16%, and the powder-to-glue ratio is 130 - 140%.

6. A two-color LED manufacturing process according to claim 1, characterized in that: In step (2), first dot a thin layer of transparent glue on the top light-emitting surface of the second LED chip, and then dot the first fluorescent glue on the thin transparent glue.

7. A two-color LED manufacturing process according to claim 1, characterized in that: When dotting the transparent glue on the first LED chip, the dispensing head first discharges glue directly above the first LED chip to form a glue drop; then the dispensing head moves vertically downward with the glue drop to the top surface of the first LED chip; after the glue drop is transferred to the top surface of the first LED chip, the dispensing head leaves vertically to complete the dotting of the transparent glue.

8. A manufacturing process for a two-color LED according to claim 1, characterized in that: The first LED chip and the second LED chip are blue light flip chips.

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