White light LED packaging structure and preparation method thereof

Abstract

The invention discloses a white light LED packaging structure which comprises a support, a blue light chip and a packaging adhesive layer. The substrate of the bracket is connected with the box dam to form a packaging cavity; the blue light chip is arranged on the substrate and is electrically connected with the substrate; the packaging adhesive layer at least covers the blue light chip; the packaging cavity comprises a first packaging cavity, a second packaging cavity and a third packaging cavity, the first packaging cavity and the second packaging cavity are arranged around the side surface of the blue light chip, and the third packaging cavity is arranged on the upper surface of the blue light chip; a first packaging adhesive layer, a second packaging adhesive layer and a third packaging adhesive layer are respectively arranged in the first packaging cavity, the second packaging cavity and the third packaging cavity; the excitation wavelength of the first red fluorescent powder in the first packaging adhesive layer is greater than the excitation wavelength of the second red fluorescent powder in the second packaging adhesive layer; the volume of the third packaging cavity is larger than the volume of the first packaging cavity and larger than the volume of the second packaging cavity. The white light LED packaging structure prepared by the invention is high in color coordinate concentration degree and high in luminous efficiency.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a white light LED packaging structure and a preparation method thereof. Background Art

[0002] Existing white light LEDs are usually obtained by mixing red phosphor, green phosphor and packaging glue and then packaging a blue light front chip. The red phosphor and green phosphor are excited by blue light to produce red light and green light, which are mixed with blue light to synthesize white light. However, red phosphor can be excited by both blue light and green light, and there is a reabsorption problem, resulting in low brightness and light efficiency of the LED; moreover, in order to improve the conversion efficiency, the amount of green phosphor is generally much larger than the amount of red phosphor. The proportion of red phosphor is small, and it is easy to have uneven distribution, resulting in low concentration of color coordinates of the LED and poor color uniformity; in addition, the light output of different sides of the blue light front chip is different. For green phosphor, the amount of blue light is surplus, and for red phosphor, the amount of blue light is insufficient. The blue light cannot be fully utilized, resulting in low brightness of the LED. Using a larger blue light front chip can achieve higher brightness, but it will increase the cost of the LED. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a white light LED packaging structure and a preparation method thereof. The white light LED packaging structure has high color coordinate concentration and high luminous efficiency.

[0004] In order to solve the above problems, the present invention discloses a white light LED packaging structure, comprising a bracket, a blue light chip and a packaging adhesive layer; the bracket comprises a substrate and a dam arranged on the substrate, the substrate and the dam are connected to form a packaging cavity; the blue light chip is arranged on the substrate and is electrically connected to the substrate; the packaging adhesive layer at least covers the blue light chip;

[0005] Wherein, the packaging cavity comprises a first packaging cavity, a second packaging cavity and a third packaging cavity, the first packaging cavity and the second packaging cavity are arranged around the side surface of the blue light chip, and the third packaging cavity is arranged on the upper surface of the blue light chip;

[0006] The first packaging cavity, the second packaging cavity and the third packaging cavity are respectively provided with a first packaging glue layer, a second packaging glue layer and a third packaging glue layer; the first packaging glue layer is a packaging glue layer mixed with a first red phosphor, the second packaging glue layer is a packaging glue layer mixed with a second red phosphor, and the third packaging glue layer is a packaging glue layer mixed with a green phosphor, and the excitation wavelength of the first red phosphor is greater than the excitation wavelength of the second red phosphor;

[0007] The volume of the third packaging cavity is greater than the volume of the first packaging cavity, and greater than the volume of the second packaging cavity.

[0008] As an improvement of the above technical solution, the volumes of the third packaging cavity, the second packaging cavity and the first packaging cavity decrease gradually.

[0009] As an improvement of the above technical solution, the volume ratio of the third packaging cavity, the second packaging cavity and the first packaging cavity is (60-80):(5-15):(3-10).

[0010] As an improvement of the above technical solution, a separation glue layer is provided between the first packaging cavity and the second packaging cavity, one side of the separation glue layer contacts the side surface of the blue light chip, the other side of the separation glue layer contacts the inner side surface of the dam, and the upper surface of the separation glue layer is flush with the upper surface of the blue light chip.

[0011] As an improvement of the above technical solution, the side surfaces of the blue light chip include a first side surface and a third side surface that are opposite to each other, and a second side surface and a fourth side surface that are opposite to each other;

[0012] The first packaging cavity includes two first packaging sub-cavities, the second packaging cavity includes two second packaging sub-cavities, the first packaging sub-cavities and the second packaging sub-cavities are alternately arranged around the side of the blue light chip; the third packaging cavity is arranged on the upper surface of the blue light chip and above the first packaging cavity and the second packaging cavity;

[0013] A separation adhesive layer is provided between the first encapsulation subcavity and the second encapsulation subcavity, one side of the separation adhesive layer contacts the side surface of the blue light chip, the other side of the separation adhesive layer contacts the inner side surface of the dam, and the upper surface of the separation adhesive layer is flush with the upper surface of the blue light chip.

[0014] As an improvement of the above technical solution, the first encapsulation glue layer at least covers the first side surface and the third side surface, the second encapsulation glue layer at least covers the second side surface and the fourth side surface, and the third encapsulation glue layer at least covers the upper surface.

[0015] As an improvement of the above technical solution, the width of the separation adhesive layer is 100 μm to 300 μm;

[0016] The separation glue layer is formed by curing white glue, and the viscosity of the white glue is 10000mPa·s to 15000mPa·s.

[0017] As an improvement of the above technical solution, the upper surfaces of the first encapsulation adhesive layer and the second encapsulation adhesive layer are flush with the upper surface of the blue light chip; the upper surface of the third encapsulation adhesive layer is flush with the upper surface of the dam.

[0018] As an improvement of the above technical solution, the blue light chip is a blue light flip chip;

[0019] The first packaging glue layer is formed by curing the first packaging glue, the first packaging glue includes silica gel and a first red phosphor, and the emission peak of the first red phosphor is 620nm to 650nm;

[0020] The second packaging glue layer is formed by curing the second packaging glue, the second packaging glue includes silica gel and a second red phosphor, and the emission peak of the second red phosphor is 650nm to 750nm;

[0021] The third packaging glue layer is formed by curing the third packaging glue, the third packaging glue includes silica gel and green phosphor, and the emission peak of the green phosphor is 510nm-515nm.

[0022] Correspondingly, the present invention also discloses a method for preparing a white light LED packaging structure, which is used to prepare the above-mentioned white light LED packaging structure, comprising the following steps:

[0023] Fixing the blue light chip on the substrate of the bracket, and electrically connecting the blue light chip to the substrate;

[0024] Separating the packaging cavity of the bracket into a first packaging cavity, a second packaging cavity and a third packaging cavity;

[0025] The first packaging cavity, the second packaging cavity and the third packaging cavity are respectively filled with packaging glue and cured to form a first packaging glue layer, a second packaging glue layer and a third packaging glue layer, thereby obtaining the white light LED packaging structure.

[0026] The implementation of the present invention has the following beneficial effects:

[0027] The present invention arranges a first packaging cavity and a second packaging cavity around the side of a blue light chip, and arranges a third packaging cavity on the upper surface of the blue light chip. A first packaging glue layer mixed with a first red phosphor, a second packaging glue layer mixed with a second red phosphor, and a third packaging glue layer mixed with a green phosphor are respectively arranged in the first packaging cavity, the second packaging cavity, and the third packaging cavity. By arranging fluorescent glue layers of different colors on different surfaces of the blue light chip and limiting the volume relationship of the first packaging cavity, the second packaging cavity, and the third packaging cavity, the first packaging glue layer and the second packaging glue layer are arranged on the side of the blue light chip, and the third packaging glue layer is arranged on the upper surface of the chip. The light emitted from the side of the blue light chip excites the red phosphor, and the light emitted from the upper surface excites the green phosphor. The red phosphor is fully excited while avoiding the absorption of green light by the red phosphor, thereby improving the light output efficiency and brightness. By limiting the volume size of the packaging cavity, the light from different light output surfaces of the blue light chip can be fully utilized, and the distribution uniformity of the red phosphor in the packaging cavity is also significantly improved, thereby improving the color coordinate concentration and the luminous uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a top view of a white light LED packaging structure provided by an embodiment of the present invention;

[0029] Figure 2 yes Figure 1 AA section view;

[0030] Figure 3 yes Figure 1 BB cross-section diagram;

[0031] Figure 4 yes Figure 2 CC profile of ;

[0032] Figure 5 is a schematic diagram of the distribution of the packaging cavity of the white light LED packaging structure provided by an embodiment of the present invention;

[0033] Figure 6 yes Figure 5 AA section view;

[0034] Figure 7 yes Figure 5 BB cross-section diagram;

[0035] Figure 8 is a color coordinate distribution diagram of the white light LED packaging structure provided by Example 1 of the present invention;

[0036] Fig. 9 is a color coordinate distribution diagram of the white light LED packaging structure provided by Example 2 of the present invention;

[0037] Fig.10 is a color coordinate distribution diagram of the white light LED packaging structure provided by Example 3 of the present invention;

[0038] Fig.11 This is a color coordinate distribution diagram of the white light LED packaging structure provided in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0040] See also Figure 1 to Figure 4 The present invention provides a white light LED packaging structure, comprising a bracket 1, a blue light chip 2 and a packaging glue layer 3; the bracket 1 comprises a substrate 11 and a dam 12 arranged on the substrate 11, the substrate 11 and the dam 12 are connected to form a packaging cavity 13; the blue light chip 2 is arranged on the substrate 11 and is electrically connected to the substrate 11; the packaging glue layer 3 at least covers the blue light chip 2;

[0041] Among them, Figure 5 to Figure 7As shown, the packaging cavity 13 includes a first packaging cavity 131, a second packaging cavity 132 and a third packaging cavity 133, the first packaging cavity 131 and the second packaging cavity 132 are arranged around the side of the blue light chip 2, and the third packaging cavity 133 is arranged on the upper surface of the blue light chip 2;

[0042] The first packaging cavity 131, the second packaging cavity 132 and the third packaging cavity 133 are respectively provided with a first packaging glue layer 31, a second packaging glue layer 32 and a third packaging glue layer 33; the first packaging glue layer 31 is a packaging glue layer mixed with a first red phosphor, the second packaging glue layer 32 is a packaging glue layer mixed with a second red phosphor, and the third packaging glue layer 33 is a packaging glue layer mixed with a green phosphor, and the excitation wavelength of the first red phosphor is greater than the excitation wavelength of the second red phosphor;

[0043] The volume of the third packaging cavity 133 is greater than the volume of the first packaging cavity 131 , and greater than the volume of the second packaging cavity 132 .

[0044] The present invention sets a first packaging cavity 131 and a second packaging cavity 132 around the side of the blue light chip 2, and sets a third packaging cavity 133 on the upper surface of the blue light chip 2. The first packaging cavity 131, the second packaging cavity 132 and the third packaging cavity 133 are respectively provided with a first packaging glue layer 31 mixed with a first red phosphor, a second packaging glue layer 32 mixed with a second red phosphor, and a third packaging glue layer 33 mixed with a green phosphor.

[0045] That is to say, different fluorescent adhesive layers are arranged on different surfaces of the blue light chip 2, the first encapsulation adhesive layer 31 and the second encapsulation adhesive layer 32 are arranged on the side of the blue light chip 2, that is, at a lower position, and the third encapsulation adhesive layer 33 is arranged on the upper surface of the chip, that is, at a higher position. The light emitted from the side of the blue light chip 2 excites the red light phosphor, and the light emitted from the upper surface of the blue light chip 2 excites the green light phosphor. The red light phosphor is fully excited while avoiding the red light phosphor's absorption of green light, thereby improving the light output efficiency and brightness.

[0046] In addition, by limiting the volume size of the packaging cavity 13, the light from different light-emitting surfaces of the blue light chip 2 can be fully utilized. The volume of the first packaging cavity 131 is the largest, which is used to excite the green phosphor and improve the luminous efficiency. The volumes of the second packaging cavity 132 and the third packaging cavity 133 are smaller, and the first red phosphor and the second red phosphor can be evenly distributed in the first packaging cavity 131 and the second packaging cavity 132, thereby improving the color coordinate concentration and the luminous uniformity.

[0047] In a preferred embodiment, the volumes of the third packaging cavity 133, the second packaging cavity 132, and the first packaging cavity 131 decrease. The first red phosphor with a larger excitation wavelength can enhance the color rendering ability of R12 (dark blue) and R15 (Asian skin color). The second red phosphor with a smaller excitation wavelength can fill the red gap of traditional YAG yellow powder and enhance the color rendering ability of R9 (dark red). The green phosphor has a high quantum efficiency, dominates the yellow-green light color rendering, balances the color temperature and supports the light effect.

[0048] More preferably, the volume ratio of the third packaging cavity 133, the second packaging cavity 132 and the first packaging cavity 131 is (60-80):(5-15):(3-10). Exemplary are 60:5:3, 12:3:2, 60:10:3, 35:4:3 or 8:1:1, but not limited thereto. By limiting the volume ratio of the third packaging cavity 133, the second packaging cavity 132 and the first packaging cavity 131 within the above range, the utilization rate of the light emitted from different sides of the blue light chip 2 can be improved, the phosphor can be fully excited, and the brightness and light uniformity can be improved.

[0049] In one embodiment, a separation adhesive layer 4 is provided between the first encapsulation cavity 131 and the second encapsulation cavity 132, one side of the separation adhesive layer 4 contacts the side of the blue light chip 2, the other side of the separation adhesive layer 4 contacts the inner side of the dam 12, and the upper surface of the separation adhesive layer 4 is flush with the upper surface of the blue light chip 2. As a physical isolation layer, the separation adhesive layer 4 can block the direct contact between the first red phosphor and the second red phosphor of different excitation wavelengths, thereby improving the overall light effect. At the same time, the separation adhesive layer 4 can also reflect the unabsorbed blue light back to the encapsulation adhesive layer, re-excite the phosphor, and improve the light conversion efficiency. In addition, the separation adhesive layer 4 can also disperse the local heat accumulation of the encapsulation adhesive layer and delay the light decay.

[0050] In a preferred embodiment, the side surface of the blue light chip 2 includes an opposite first side surface 21 and a third side surface 23, and an opposite second side surface 22 and a fourth side surface 24;

[0051] The first packaging cavity 131 includes two first packaging sub-cavities 131a, and the second packaging cavity 132 includes two second packaging sub-cavities 132a. The first packaging sub-cavities 131a and the second packaging sub-cavities 132a are alternately arranged around the side of the blue light chip 2, that is, the first packaging sub-cavity 131a, the second packaging sub-cavity 132a, the first packaging sub-cavity 131a and the second packaging sub-cavity 132a are arranged around the side of the blue light chip 2 respectively; the third packaging cavity 133 is arranged on the upper surface of the blue light chip 2 and above the first packaging cavity 131 and the second packaging cavity 132;

[0052] A separation adhesive layer 4 is provided between the first encapsulation sub-cavity 131a and the second encapsulation sub-cavity 132a, one side of the separation adhesive layer 4 contacts the side surface of the blue light chip 2, and the other side of the separation adhesive layer 4 contacts the inner side surface of the dam 12, and the upper surface of the separation adhesive layer 4 is flush with the upper surface of the blue light chip 2.

[0053] The first encapsulation glue layer 31 at least covers the first side surface 21 and the third side surface 23, the second encapsulation glue layer 32 at least covers the second side surface 22 and the fourth side surface 24, and the third encapsulation glue layer 33 at least covers the upper surface. That is, the first red phosphor is excited by the blue light emitted from the first side surface 21 and the third side surface 23 of the blue light chip 2, the second red phosphor is excited by the blue light emitted from the second side surface 22 and the fourth side surface 24 of the blue light chip 2, and the green phosphor is excited by the blue light emitted from the upper surface of the blue light chip 2, thereby forming a structure with two layers, the lower layer consisting of four cavities.

[0054] In a preferred embodiment, the cross-sectional shape of the blue light chip 2 in the top view is a rectangle, the cross-sectional shape of the lower surface where the dam 12 contacts the substrate 11 is also a rectangle, and the separation adhesive layer 4 connects the corners of the blue light chip 2 with the corresponding corners of the lower surface of the dam 12, thereby obtaining the first packaging sub-cavity 131a and the second packaging sub-cavity 132a. It can be understood that the volume of the packaging cavity 13 can be adjusted by the shape and size of the substrate 11 and the dam 12, or by the shape and size of the blue light chip 2, or by combining the two.

[0055] In a preferred embodiment, the width of the separation adhesive layer 4 is 100 μm to 300 μm. If the width of the separation adhesive layer 4 is less than 100 μm, it is difficult to achieve the isolation effect between the first packaging cavity 131 and the second packaging cavity 132; if the width of the separation adhesive layer 4 is greater than 300 μm, the volume of the first packaging cavity 131 and the second packaging cavity 132 will be reduced, thereby affecting the luminous effect. Preferably, the width of the separation adhesive layer 4 is 100 μm to 250 μm.

[0056] Optionally, the separation glue layer 4 is formed by curing white glue, the white glue includes silica gel and reflective particles, the reflective particles are one or more of Al2O3, MgO, BaSO4, TiO2, SiO2, ZrO2, and the viscosity of the white glue is 10000mPa·s to 15000mPa·s, exemplarily 11000mPa·s, 11500mPa·s, 12000mPa·s, 13000mPa·s or 14000mPa·s, but not limited thereto. Too high viscosity may cause problems such as uneven coating and residual bubbles, while too low viscosity may cause problems such as sagging penetration and insufficient mechanical strength. By limiting the viscosity of the white glue, the light efficiency and reliability of the blue light chip can be maximized without sacrificing color rendering.

[0057] In order to reduce the difficulty of preparation and ensure the regularity of the packaging structure, the upper surfaces of the first packaging glue layer 31 and the second packaging glue layer 32 are flush with the upper surface of the blue light chip 2; the upper surface of the third packaging glue layer 33 is flush with the upper surface of the dam 12.

[0058] Optionally, the blue light chip 2 is a blue light flip chip, which reduces the usage of welding wires and improves the air tightness of the package.

[0059] The first packaging glue layer 31 is formed by curing a first packaging glue, wherein the first packaging glue includes silica gel and a first red phosphor, and the emission peak of the first red phosphor is 620 nm to 650 nm.

[0060] The second packaging glue layer 32 is formed by curing the second packaging glue, wherein the second packaging glue includes silica gel and a second red phosphor, and the emission peak of the second red phosphor is 650nm-750nm.

[0061] The third packaging glue layer 33 is formed by curing a third packaging glue, wherein the third packaging glue includes silica gel and green phosphor, and the emission peak of the green phosphor is 510 nm to 515 nm.

[0062] The present invention also provides a method for preparing a white light LED packaging structure, which is used to prepare the above-mentioned white light LED packaging structure, comprising the following steps:

[0063] S1 . Fix the blue light chip 2 on the substrate 11 of the bracket 1 , and electrically connect the blue light chip 2 to the substrate 11 .

[0064] S2. Separate the packaging cavity 13 of the bracket 1 into a first packaging cavity 131 , a second packaging cavity 132 and a third packaging cavity 133 .

[0065] In one embodiment, the separator glue is filled layer by layer by scoring and dotting white glue, and then the separator glue is baked to set at a temperature of 140° C. to 160° C. for 20 min to 40 min.

[0066] S3, filling and curing the packaging glue in the first packaging cavity 131, the second packaging cavity 132 and the third packaging cavity 133 respectively to form a first packaging glue layer 31, a second packaging glue layer 32 and a third packaging glue layer 33, so as to obtain the white light LED packaging structure.

[0067] Specifically, the following steps are included:

[0068] S31, filling the first packaging glue into the first packaging cavity 131, filling the second packaging glue into the second packaging cavity 132, and then baking the first packaging glue and the second packaging glue to shape, the temperature is 140° C. to 160° C., and the time is 70 min to 80 min.

[0069] S32, filling the third packaging cavity 133 with a third packaging adhesive, and then baking the third packaging adhesive to set the third packaging adhesive at a temperature of 140° C. to 160° C. for 70 min to 80 min.

[0070] It is understandable that the separation adhesive layer 4 can also be prepared during the preparation process of the bracket 1. Specifically, the mold is used to simultaneously complete the injection molding of the dam 12 and the separation adhesive layer 4. The separation adhesive layer 4 and the dam 12 can be made of the same material. For example, polyphthalamide (PPA) or a polymer of 1,4-cyclohexanedimethanol and dimethyl terephthalate (PCT) can be selected. Subsequently, the blue light chip 2 is fixed in the bracket 1 and the first encapsulation adhesive layer 31, the second encapsulation adhesive layer 32 and the third encapsulation adhesive layer 33 are formed in the first encapsulation cavity 131, the second encapsulation adhesive layer 132 and the third encapsulation adhesive layer 133 respectively. The specific steps are the same as above and will not be repeated here.

[0071] The present invention will be further described below with specific embodiments:

[0072] Example 1

[0073] This embodiment provides a white light LED packaging structure, including a bracket, a blue light chip and a packaging adhesive layer. The bracket includes a substrate and a dam arranged on the substrate, and the substrate and the dam are connected to form a packaging cavity. The blue light chip is arranged on the substrate and is electrically connected to the substrate. The packaging adhesive layer at least covers the blue light chip.

[0074] The packaging cavity comprises a first packaging cavity, a second packaging cavity and a third packaging cavity. The first packaging cavity and the second packaging cavity are arranged around the side surface of the blue light chip, and the third packaging cavity is arranged on the upper surface of the blue light chip.

[0075] The first packaging cavity, the second packaging cavity and the third packaging cavity are respectively provided with a first packaging glue layer, a second packaging glue layer and a third packaging glue layer. The first packaging glue layer is a packaging glue layer mixed with a first red phosphor, the second packaging glue layer is a packaging glue layer mixed with a second red phosphor, and the third packaging glue layer is a packaging glue layer mixed with a green phosphor. The excitation wavelength of the first red phosphor is 620nm to 650nm, and the excitation wavelength of the second red phosphor is 650nm to 750nm.

[0076] The volume ratio of the third packaging cavity, the second packaging cavity and the first packaging cavity is 8:1:1.

[0077] Example 2

[0078] This embodiment provides a white light LED packaging structure, which is different from Embodiment 1 in that the volume ratio of the third packaging cavity, the second packaging cavity and the first packaging cavity is 16:3:1.

[0079] The rest are the same as in Example 1.

[0080] Example 3

[0081] This embodiment provides a white light LED packaging structure, which is different from the embodiment 2 in that the side of the blue light chip includes a first side and a third side opposite to each other, and a second side and a fourth side opposite to each other. The first packaging cavity includes two first packaging sub-cavities, the second packaging cavity includes two second packaging sub-cavities, and the first packaging sub-cavities and the second packaging sub-cavities are alternately arranged around the side of the blue light chip; the third packaging cavity is arranged on the upper surface of the blue light chip and above the first packaging cavity and the second packaging cavity. The volumes of the two first packaging sub-cavities are the same, and the volumes of the two second packaging sub-cavities are the same.

[0082] The rest is the same as Example 2.

[0083] Comparative Example 1

[0084] This comparative example provides a white light LED packaging structure, which differs from Example 1 in that the packaging glue layer is formed by curing the packaging glue, and the packaging glue includes silica gel, a first red phosphor, a second red phosphor and a green phosphor, and the mass ratio of the first red phosphor, the second red phosphor and the green phosphor is 1:1:8.

[0085] The rest are the same as in Example 1.

[0086] The white light LED packaging structures of Examples 1 to 3 and Comparative Example 1 were tested, the light efficiency improvement of Examples 1 to 3 relative to Comparative Example 1 was calculated, and the color coordinate distribution diagrams of Examples 1 to 3 and Comparative Example 1 were drawn. The specific results are shown in the following tables and Figure 8 to Figure 11 shown.

[0087] Lighting effect improvement Example 1 1.1％ Example 2 1.5％ Example 3 2.1％

[0088] It can be seen from the test results that the white light LED packaging structure prepared by the present invention has a high color coordinate concentration, and the light extraction efficiency and color rendering are also significantly improved.

[0089] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A white light LED packaging structure, characterized in that: The invention comprises a bracket, a blue light chip and a packaging adhesive layer; the bracket comprises a substrate and a dam arranged on the substrate, the substrate and the dam are connected to form a packaging cavity; the blue light chip is arranged on the substrate and is electrically connected to the substrate; the packaging adhesive layer at least covers the blue light chip; Wherein, the packaging cavity comprises a first packaging cavity, a second packaging cavity and a third packaging cavity, the first packaging cavity and the second packaging cavity are arranged around the side surface of the blue light chip, and the third packaging cavity is arranged on the upper surface of the blue light chip; The first packaging cavity, the second packaging cavity and the third packaging cavity are respectively provided with a first packaging glue layer, a second packaging glue layer and a third packaging glue layer; the first packaging glue layer is a packaging glue layer mixed with a first red phosphor, the second packaging glue layer is a packaging glue layer mixed with a second red phosphor, and the third packaging glue layer is a packaging glue layer mixed with a green phosphor, and the excitation wavelength of the first red phosphor is greater than the excitation wavelength of the second red phosphor; The volume of the third packaging cavity is greater than the volume of the first packaging cavity, and greater than the volume of the second packaging cavity.

2. The white light LED packaging structure according to claim 1, characterized in that: The volumes of the third packaging cavity, the second packaging cavity and the first packaging cavity decrease gradually.

3. The white light LED packaging structure according to claim 2, characterized in that: The volume ratio of the third packaging cavity, the second packaging cavity and the first packaging cavity is (60-80):(5-15):(3-10).

4. The white light LED packaging structure according to claim 1, characterized in that: A separation adhesive layer is provided between the first packaging cavity and the second packaging cavity, one side of the separation adhesive layer contacts the side surface of the blue light chip, the other side of the separation adhesive layer contacts the inner side surface of the dam, and the upper surface of the separation adhesive layer is flush with the upper surface of the blue light chip.

5. The white light LED packaging structure according to claim 1, characterized in that: The side surfaces of the blue light chip include a first side surface and a third side surface that are opposite to each other, and a second side surface and a fourth side surface that are opposite to each other; The first packaging cavity includes two first packaging sub-cavities, the second packaging cavity includes two second packaging sub-cavities, the first packaging sub-cavities and the second packaging sub-cavities are alternately arranged around the side of the blue light chip; the third packaging cavity is arranged on the upper surface of the blue light chip and above the first packaging cavity and the second packaging cavity; A separation adhesive layer is provided between the first encapsulation subcavity and the second encapsulation subcavity, one side of the separation adhesive layer contacts the side surface of the blue light chip, the other side of the separation adhesive layer contacts the inner side surface of the dam, and the upper surface of the separation adhesive layer is flush with the upper surface of the blue light chip.

6. The white light LED packaging structure according to claim 5, characterized in that: The first packaging glue layer at least covers the first side surface and the third side surface, the second packaging glue layer at least covers the second side surface and the fourth side surface, and the third packaging glue layer at least covers the upper surface.

7. The white light LED packaging structure according to claim 4 or 5, characterized in that: The width of the separation adhesive layer is 100 μm to 300 μm; The separation glue layer is formed by curing white glue, and the viscosity of the white glue is 10000mPa·s to 15000mPa·s.

8. The white light LED packaging structure according to claim 1, characterized in that: The upper surfaces of the first packaging adhesive layer and the second packaging adhesive layer are both flush with the upper surface of the blue light chip; the upper surface of the third packaging adhesive layer is flush with the upper surface of the dam.

9. The white light LED packaging structure according to claim 1, characterized in that: The blue light chip is a blue light flip chip; The first packaging glue layer is formed by curing the first packaging glue, the first packaging glue includes silica gel and a first red phosphor, and the emission peak of the first red phosphor is 620nm to 650nm; The second packaging glue layer is formed by curing the second packaging glue, the second packaging glue includes silica gel and a second red phosphor, and the emission peak of the second red phosphor is 650nm to 750nm; The third packaging glue layer is formed by curing the third packaging glue, the third packaging glue includes silica gel and green phosphor, and the emission peak of the green phosphor is 510nm-515nm.

10. A method for preparing a white light LED packaging structure, used for preparing the white light LED packaging structure according to any one of claims 1 to 9, characterized in that: The following steps are involved: Fixing the blue light chip on the substrate of the bracket, and electrically connecting the blue light chip to the substrate; Separating the packaging cavity of the bracket into a first packaging cavity, a second packaging cavity and a third packaging cavity; The first packaging cavity, the second packaging cavity and the third packaging cavity are respectively filled with packaging glue and cured to form a first packaging glue layer, a second packaging glue layer and a third packaging glue layer, thereby obtaining the white light LED packaging structure.

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