COB high light efficiency packaging structure

Abstract

The utility model discloses a kind of COB high luminous efficiency packaging structures, including substrate, multiple LED chips and encapsulation adhesive layer;Dam is equipped on the substrate, multiple the LED chip is spaced and located in the dam and is electrically connected with the substrate, the encapsulation adhesive layer covers the LED chip;White reflective layer is equipped between multiple the LED chip, the bottom of the white reflective layer and adjacent the LED chip between there is preset distance, the sidewall of the white reflective layer and the surface of the substrate form preset included angle, the preset included angle is less than or equal to 90 °. The COB high luminous efficiency packaging structure provided by the utility model can improve macula problem while improving luminous efficiency.

Description

Technical Field

[0001] This utility model relates to the field of COB packaging technology, and in particular to a COB high-efficiency packaging structure. Background Technology

[0002] Multi-chip COB (Chip On Board) packaging is a low-cost packaging method that directly attaches multiple LED chips to a substrate using die bond adhesive, thereby significantly shortening the process flow. Figure 1 The existing COB (Chip-on-Board) packaging structure includes a substrate 1', an LED chip 2', and an encapsulating layer 3'. The encapsulating layer has a high refractive index, while air has a low refractive index. Most of the light emitted by the LED chip is totally internally reflected back to the substrate at the interface between the encapsulating layer and air. Since the substrate is often made of mirrored aluminum, the reflected light is further reflected at the substrate. The light is weakened by absorption by the substrate and encapsulating layer during multiple reflections until it reaches a dam 4' with diffuse reflection characteristics and a certain tilt angle, at which point it finally exits the encapsulating layer. This significantly reduces luminous efficiency. Furthermore, the light after multiple total internal reflections is fully excited by the phosphor in the encapsulating layer 3', resulting in an overall yellowish color. Finally, the light exits at the dam 4', causing a yellowish ring to form on the outermost edge. While coating the substrate surface with white oil or creating a microporous structure on the substrate surface can reduce total internal reflection losses, this approach has drawbacks such as affecting the substrate's reflectivity and presenting processing difficulties. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a COB high luminous efficiency packaging structure that can improve luminous efficiency while improving the macular problem.

[0004] To solve the above-mentioned technical problems, this utility model provides a COB high-efficiency packaging structure, including a substrate, multiple LED chips and an encapsulating adhesive layer; the substrate is provided with a dam, the multiple LED chips are spaced apart in the dam and electrically connected to the substrate, and the encapsulating adhesive layer covers the LED chips;

[0005] A white reflective layer is provided between multiple LED chips. The bottom of the white reflective layer is at a preset distance from the adjacent LED chip. The sidewall of the white reflective layer forms a preset angle with the surface of the substrate. The preset angle is less than or equal to 90°.

[0006] As an improvement to the above scheme, the preset included angle is 55° to 85°.

[0007] As an improvement to the above scheme, the ratio of the surface area of ​​the substrate to the surface area of ​​the white reflective layer is 1:(0.05~0.3).

[0008] As an improvement to the above scheme, the sidewalls of the white reflective layer are planar or curved.

[0009] As an improvement to the above scheme, the preset distance is 50μm to 150μm.

[0010] As an improvement to the above solution, the top surface of the LED chip is higher than the top surface of the white reflective layer.

[0011] As an improvement to the above scheme, the height of the white reflective layer is 10μm to 100μm.

[0012] As an improvement to the above solution, the white reflective layer includes silicone and white reflective particles, wherein the white reflective particles include one or more of barium sulfate powder, aluminum oxide powder, magnesium oxide powder, titanium oxide powder, and zirconium oxide powder.

[0013] As an improvement to the above scheme, the particle size of the white reflective particles is 0.5μm to 1.5μm.

[0014] As an improvement to the above solution, the substrate is a mirror aluminum substrate, and the LED chip is a standard LED chip.

[0015] Implementing this utility model has the following beneficial effects:

[0016] In the high-efficiency COB packaging structure provided by this invention, a white reflective layer is provided between the LED chips. The bottom of the white reflective layer is at a predetermined distance from the adjacent LED chip, and the sidewall of the white reflective layer forms a predetermined angle with the surface of the substrate. By fully utilizing the sidewall of the white reflective layer, the light emission efficiency after reflection from around the LED chips and the encapsulating adhesive layer is improved. The white reflective layer, with its diffuse reflection effect, also enhances the light diffusion effect. The high-efficiency COB packaging structure provided by this invention can significantly improve the yellow spot problem while increasing luminous efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of an existing COB packaging structure;

[0018] Figure 2 This is a schematic diagram of the COB high-efficiency packaging structure provided in one embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the COB high-efficiency packaging structure provided in one embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of the COB high-efficiency packaging structure provided in one embodiment of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this utility model clearer, the following will describe this utility model in further detail with reference to the accompanying drawings. It is hereby declared that the terms "up," "down," "left," "right," "front," "back," "inner," and "outer," etc., appearing or about to appear in this document, are based solely on the accompanying drawings and are not intended to specifically limit this utility model.

[0022] like Figures 2-4 As shown, this utility model embodiment provides a COB high luminous efficiency packaging structure, including a substrate 1, a plurality of LED chips 2 and an encapsulating adhesive layer 3; the substrate 1 is provided with a dam 4, the plurality of LED chips 2 are spaced apart in the dam 4 and electrically connected to the substrate 1, and the encapsulating adhesive layer 3 covers the LED chips 2.

[0023] A white reflective layer 5 is provided between multiple LED chips 2. The bottom of the white reflective layer 5 is at a preset distance S from the adjacent LED chip 2. The sidewall of the white reflective layer 5 forms a preset angle θ with the surface of the substrate 1. The preset angle θ is less than or equal to 90°.

[0024] In the high-efficiency COB packaging structure provided by this utility model, a white reflective layer 5 is provided between the LED chips 2. The bottom of the white reflective layer 5 is at a preset distance from the adjacent LED chip 2, and the sidewall of the white reflective layer 5 forms a preset angle with the surface of the substrate 1. By fully utilizing the sidewall of the white reflective layer 5, the light emission efficiency after reflection from the surrounding area of ​​the LED chip 2 and the encapsulating adhesive layer 3 is improved. The white reflective layer 5, which has a diffuse reflection effect, can also enhance the light diffusion effect. The high-efficiency COB packaging structure provided by this utility model can significantly improve the yellow spot problem while improving luminous efficiency.

[0025] It is understood that the shape of the white reflective layer can be one or more of the following: hemispherical, teardrop, frustum, pyramidal, or conical, but is not limited thereto.

[0026] The tilted sidewalls alter the light reflection path, making it easier for light emitted from the chip's sidewalls to exit the light-emitting surface and preventing absorption by the substrate 1. Simultaneously, the preset angle reduces the probability of total internal reflection at the interface between the LED chip 2 and the white reflective layer 5, resulting in multiple cross-mixing of light from adjacent LED chips 2 within the white reflective layer 5, leading to a more uniform light distribution. In a preferred embodiment, the preset angle θ is between 55° and 85°. Controlling the preset angle within this preferred range balances luminous efficiency and uniformity. If the preset angle is too small, the light still strikes the substrate 1 at a high angle, resulting in insufficient reflection; if the preset angle is too large, the light is excessively concentrated towards the center, leading to uneven light distribution.

[0027] Optionally, the sidewalls of the white reflective layer 5 can be planar or curved. In one embodiment, the sidewalls of the white reflective layer 5 are planar, and the angle θ between the plane containing the sidewalls and the horizontal plane containing the substrate 1 is 55° to 85°. Setting the sidewalls to be planar can improve manufacturing efficiency. In another embodiment, the sidewalls are curved. Setting the sidewalls to be curved increases the area of ​​the sidewalls, allowing light to be fully refracted and reflected on the curved sidewalls, further improving light extraction efficiency. Specifically, the curved surface can be formed by the white reflective layer 5 protruding towards the LED chip 2, and the angle θ between the tangent at the apex of the curved surface and the horizontal plane containing the substrate 1 is 55° to 85°.

[0028] It is understandable that the white reflective layer 5 can be obtained by dispensing or photolithography; no specific limitation is made here. If the white reflective layer 5 is formed by dispensing, white reflective adhesive can be dispensed into the gap between adjacent LED chips 2 during or after die bonding. If the white reflective layer 5 is formed by photolithography, it can be formed before die bonding, and then the LED chips 2 can be die bonded and wire bonded.

[0029] In one embodiment, the top surface of the LED chip 2 is higher than the top surface of the white reflective layer 5. In a preferred embodiment, the height H of the white reflective layer is 10 μm to 100 μm. Light emitted from the side of the LED chip 2 can be blocked and refracted by the white reflective layer 5, minimizing light loss caused by absorption by adjacent LED chips 2.

[0030] In a preferred embodiment, the preset distance S is 50μm to 150μm. This preset distance ensures sufficient space for the white reflective layer 5 while also considering the reliability of the LED chip 2 die bonding process.

[0031] In a preferred embodiment, the ratio of the surface area of ​​the substrate 1 to the surface area of ​​the white reflective layer 5 is 1:(0.05 to 0.3). The increased diffuse reflection area is controlled to be 5% to 30% of the area of ​​the substrate 1, and the angle of the total internal reflection light is changed without reducing the high reflectivity of the substrate 1.

[0032] It is understood that the white reflective layer 5 is a white reflective adhesive layer. To achieve high reflectivity, white reflective particles are typically added to the silicone. These white reflective particles include one or more of barium sulfate powder, aluminum oxide powder, magnesium oxide powder, titanium oxide powder, and zirconium oxide powder. The addition of these white reflective particles makes the white reflective layer 5 appear white and gives it excellent specular and diffuse reflection properties, with a reflectivity greater than 90%. In a preferred embodiment, the particle size of the white reflective particles is 0.5 μm to 1.5 μm. If the particle size of the white reflective particles is too large, it will cause excessive porosity in the white reflective layer 5, resulting in the white reflective layer 5 being mostly silicone, thus reducing the brightness of the LED chip 2.

[0033] Optionally, the substrate 1 is one of a ceramic substrate, an aluminum substrate, or a metal-based printed circuit board. Preferably, the substrate 1 is a mirror aluminum substrate, and the reflectivity of the white reflective layer 5 is less than that of the mirror aluminum substrate. The LED chip 2 is a standard-mount LED chip.

[0034] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications are also considered to be within the protection scope of this utility model.

Claims

1. A COB high-efficiency luminous efficacy packaging structure, characterized in that, The device includes a substrate, multiple LED chips, and an encapsulating adhesive layer; a dam is provided on the substrate, and the multiple LED chips are spaced apart within the dam and electrically connected to the substrate; the encapsulating adhesive layer covers the LED chips. A white reflective layer is provided between multiple LED chips. The bottom of the white reflective layer is at a preset distance from the adjacent LED chip. The sidewall of the white reflective layer forms a preset angle with the surface of the substrate. The preset angle is less than or equal to 90°.

2. The COB high-efficiency packaging structure as described in claim 1, characterized in that, The preset included angle is 55° to 85°.

3. The COB high-efficiency packaging structure as described in claim 1, characterized in that, The ratio of the surface area of ​​the substrate to the surface area of ​​the white reflective layer is 1:(0.05~0.3).

4. The COB high-efficiency packaging structure as described in claim 1, characterized in that, The sidewalls of the white reflective layer are either flat or curved.

5. The COB high-efficiency packaging structure as described in claim 1, characterized in that, The preset distance is 50μm to 150μm.

6. The COB high-efficiency packaging structure as described in claim 1, characterized in that, The top surface of the LED chip is higher than the top surface of the white reflective layer.

7. The COB high-efficiency packaging structure as described in claim 6, characterized in that, The height of the white reflective layer is 10μm to 100μm.

8. The COB high-efficiency packaging structure as described in claim 1, characterized in that, The white reflective layer comprises silicone and white reflective particles, wherein the white reflective particles comprise one or more of barium sulfate powder, aluminum oxide powder, magnesium oxide powder, titanium oxide powder, and zirconium oxide powder.

9. The COB high-efficiency packaging structure as described in claim 8, characterized in that, The white reflective particles have a particle size of 0.5 μm to 1.5 μm.

10. The COB high-efficiency packaging structure as described in claim 1, characterized in that, The substrate is a mirror-finished aluminum substrate, and the LED chip is a standard-mount LED chip.

Images