LED packaging structure, packaging method and backlight module

Abstract

The application relates to the technical field of LED packaging and discloses an LED packaging structure, an encapsulation method and a backlight module. The LED packaging structure comprises a main body substrate and at least two light-emitting units. The light-emitting unit comprises a transition substrate, a connecting component, an LED chip and a fluorescent glue layer. The transition substrate is arranged between the main body substrate and the connecting component. The connecting component comprises a component main body and a plurality of metal layers arranged on the surface of the component main body. The LED chip is attached to the metal layer, and the light-emitting direction of the LED chip is a horizontal direction. A hollow part for exposing the transition substrate or the main body substrate is formed between the light-emitting units. The fluorescent glue layer is arranged on the main body substrate and covers the LED chip, the surface of the connecting component and the side surface of the transition substrate, and fills the hollow part. The application can improve the light-emitting angle of the LED chip, improve the visual effect of the backlight module and eliminate the phenomenon of uneven brightness.

Description

Technical Field

[0001] This invention relates to the technical field of LEDs, and more particularly to an LED packaging structure, packaging method, and backlight module. Background Technology

[0002] The core structure of a conventional LED packaging structure consists of a support frame 90, an LED chip 40, and a phosphor layer 50, such as... Figure 1 As shown, the chip emits light vertically upwards, with the light mainly emanating from above the LED chip 40, exhibiting good luminous directionality. However, the conventional luminous angle is typically only around 100°-120°, and the light intensity distribution shows a strong light intensity at the center and a weak light intensity around the edges.

[0003] The core requirement of a display screen backlight is to achieve uniform light mixing to ensure the consistency of the displayed image and avoid problems such as alternating bright and dark areas and uneven light spots. Traditional LED backlight modules typically consist of a substrate 100, LED chips 40, a lens 110, and a diffuser 120. Figure 2 As shown. Conventional LED packaging structures have a small emission angle. When used as a backlight for a display screen, this results in extremely strong light intensity directly above the LED, while the light intensity at the edges is significantly reduced, easily leading to alternating bright and dark areas, i.e., uneven light mixing. Therefore, it is necessary to reduce the spacing between the LED chips 40 so that the emission edges of two adjacent LED chips 40 overlap, achieving the same luminous intensity as the area directly above the LED chip 40. However, reducing the spacing requires a larger number of LED chips 40, increasing costs. Alternatively, without reducing the spacing, the distance between the LED chips 40 and the diffuser sheet 120 needs to be increased, i.e., increasing the light mixing distance, so that the light emitted from the LED edges overlaps at a greater distance. This results in a thicker backlight module, which is not conducive to the application of thinner displays. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an LED packaging structure, packaging method and backlight module, which can improve the light emission angle of LED chip, improve the visual effect of backlight module and eliminate uneven brightness.

[0005] To solve the above-mentioned technical problems, the first aspect of the present invention provides an LED packaging structure, including: a main substrate and at least two light-emitting units, wherein the light-emitting unit includes a transition substrate, a connecting component, an LED chip and a phosphor layer; The transition substrate is disposed between the main substrate and the connecting component. The connecting component includes a component body and several metal layers disposed on the surface of the component body. The LED chip is attached to the metal layers and arranged around the connecting component. The light emission direction of the LED chip is horizontal. The light-emitting units have cutouts formed between them to expose the transition substrate or the main substrate. The phosphor layer is disposed on the main substrate and covers the LED chip, the surface of the connecting component and the side of the transition substrate, and fills the cutouts.

[0006] As an improvement to the above solution, the metal layer is an L-shaped metal sheet, which is nested with the main body of the component. The vertical section of the L-shaped metal sheet is attached to the side wall of the main body of the component, and the horizontal section of the L-shaped metal sheet is welded and fixed to the bottom of the main body of the component. The LED chip is attached to the side of the metal layer opposite to the main body of the component.

[0007] As an improvement to the above solution, the connecting component is welded and fixed to the transition substrate; the length of the transition substrate is greater than the length of the connecting component.

[0008] As an improvement to the above scheme, the length of the transition substrate is L1, the length of the connecting component is L2, and the thickness of the LED chip is L3, satisfying 0.6L3≤L1-L2≤L3.

[0009] As an improvement to the above solution, the LED chip is a flip chip, and the electrodes of the LED chip are electrically connected to the metal layer through a first solder paste; the transition substrate and the main substrate are soldered and fixed together through the first solder paste. The melting point of the first solder paste is 200℃-230℃; wherein, the raw materials for preparing the first solder paste include tin-copper alloy and flux.

[0010] As an improvement to the above solution, the connecting component is fixed to the transition substrate by soldering with a second solder paste; The melting point of the second solder paste is 230℃-250℃; wherein, the raw materials for preparing the second solder paste include tin-antimony alloy and flux.

[0011] As an improvement to the above solution, the LED packaging structure further includes a white adhesive layer, which is disposed on the fluorescent adhesive layer; The thickness of the white glue layer is 100μm-200μm.

[0012] As an improvement to the above solution, the LED chips are evenly arranged on the main substrate, and the number of LED chips is 4-8.

[0013] A second aspect of the present invention provides a packaging method for the aforementioned LED packaging structure, comprising the following steps: The transition substrate is fixed to the connecting component, the connecting component including a component body and several metal layers disposed on the surface of the component body; The LED chip is fixed to the surface of the metal layer, so that the light emission direction of the LED chip is horizontal, to obtain a semi-finished product; A main substrate is provided, and the semi-finished product is fixed to the main substrate. The connecting component includes a component body and a plurality of metal layers disposed on the surface of the component body. A fluorescent adhesive layer is deposited on the main substrate to cover the semi-finished product.

[0014] A third aspect of the present invention provides an LED backlight module, including the aforementioned LED packaging structure.

[0015] Implementing this invention has the following beneficial effects: In this application, LED chips are placed on the outside of the metal layer, changing the traditional vertical light emission method and enabling a more uniform distribution of the light source in the horizontal direction. The metal layer reflects or refracts the lateral light emitted by the LED chips, changing its propagation direction and increasing the light coverage angle. This reduces the amount of lateral light absorbed by the main substrate. Simultaneously, the phosphor layer covering the front of the LED chips, through diffuse reflection, transforms the point light source of the chips into a surface light source, widening the light diffusion range and making the light emission more uniform and widespread. This effectively improves the light emission angle of the LED chips and mixes the light emitted from different LED chips, forming more uniform emitted light in color and intensity, preventing excessive concentration of light in certain areas and avoiding bright spots. This effectively eliminates uneven brightness caused by differences in LED chip design or improper layout. Attached Figure Description

[0016] Figure 1 : A schematic diagram of the existing LED packaging structure; Figure 2 : A schematic diagram of the operation of an LED backlight module in the prior art; Figure 3 : A schematic diagram of an LED packaging structure according to the present invention; Figure 4 : A top view of an LED packaging structure according to the present invention; Figure 5 : A top view of another LED packaging structure in this invention; Figure 6 : A schematic diagram of the connecting component in this invention; Figure 7 : A bottom view of the connecting component in this invention; Figure 8 Another schematic diagram of an LED packaging structure in this invention; Figure 9 : Schematic diagrams of other LED packaging structures in this invention; Figure 10Top view of other LED packaging structures in this invention; Figure 11 : A schematic diagram of the LED packaging structure after step (1) of the present invention is completed; Figure 12 : A schematic diagram of the positioning device in this invention; Figure 13 : A schematic diagram of the LED packaging structure after step (21) of the present invention is completed; Figure 14 : A schematic diagram of the LED packaging structure after step (22) of the present invention is completed; Figure 15 : A schematic diagram of the LED packaging structure after step (23) of the present invention is completed; Figure 16 : A schematic diagram of the LED packaging structure after step (3) of the present invention is completed; Figure 17 The light intensity distribution curve of the LED packaging structure provided in Embodiment 1 of this invention; Figure 18 The light intensity distribution curve of the LED packaging structure provided in Embodiment 2 of this invention; Figure 19 The light intensity distribution curve of the LED packaging structure provided in Embodiment 3 of this invention; Figure 20 : The light intensity distribution curve of the LED packaging structure provided in Comparative Example 1 of this invention; Figure 21 : The light intensity distribution curve of the LED packaging structure provided in Comparative Example 2 of this invention; Figure 22 : A diagram illustrating the light mixing effect of the LED backlight module provided in Embodiment 3 of this invention; Figure 23 : Comparative Example 2 of this invention provides a diagram showing the light mixing effect of the LED backlight module.

[0017] Reference numerals: 10-Main substrate; 20-Transition substrate; 30-Connecting component; 31-Component body; 32-Metal layer; 33-Koilout; 40-LED chip; 41-Electrode; 50-Fluorescent adhesive layer; 60-White adhesive layer; 70-First solder paste; 80-Positioning device; 81-Rotating disk; 82-Positioning pin; 90-Bracket; 100-Substrate; 110-Lens; 120-Diffuser. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments will be described in further detail below.

[0019] To address the above problems, the first aspect of this invention provides an LED packaging structure, please refer to [link / reference]. Figures 3-5 It includes: a main substrate 10 and at least two light-emitting units, wherein the light-emitting unit includes a transition substrate 20, a connecting component 30, an LED chip 40 and a phosphor layer 50; The transition substrate 20 is disposed between the main substrate 10 and the connecting component 30. The connecting component 30 includes a component body 31 and a plurality of metal layers 32 disposed on the surface of the component body 31. The LED chip 40 is attached to the metal layers 32 and arranged around the connecting component 30. The light emission direction of the LED chip 40 is horizontal. A cutout portion 33 is formed between the light emission units to expose the transition substrate 20 or the main substrate 10. The phosphor layer 50 is disposed on the main substrate 10 and covers the LED chip 40, the surface of the connecting component 30 and the side of the transition substrate 20, and fills the cutout portion 33.

[0020] In this application, LED chips 40 are disposed on the outside of the metal layer 32, changing the traditional vertical light emission method and enabling the light source to be distributed more evenly in the horizontal direction. The metal layer 32 reflects or refracts the lateral light emitted by the LED chips 40, changing its propagation direction and increasing the light coverage angle. This reduces the lateral light absorbed by the main substrate 10. Simultaneously, the phosphor layer 50 covers the front of the LED chips 40, and through diffuse reflection, transforms the point light source of the chip into a surface light source, widening the light diffusion range and making the light emission more uniform and widespread. This effectively improves the light emission angle of the LED chips 40 and mixes the light emitted by different LED chips 40, forming more uniform emitted light in color and intensity. This avoids excessive concentration of light in certain areas, preventing bright spots and effectively eliminating uneven brightness caused by differences in the LED chips 40 or unreasonable layout.

[0021] Preferably, please refer to Figure 6 and Figure 7The metal layer 32 is an L-shaped metal sheet, nested and fitted with the main body 31. The vertical section of the L-shaped metal sheet is attached to the side wall of the main body 31, and the horizontal section is welded to the bottom of the main body 31. The LED chip 40 is attached to the side of the metal layer 32 opposite to the main body 31. Setting the metal layer 32 in an L-shape, with its vertical section attached to the side wall of the main body 31, increases the contact area between the LED chip 40 and the metal layer 32, which is beneficial for stable electrical connection, improves packaging reliability, and helps the current to be more evenly distributed among the LED chips 40, improving the consistency of the luminous intensity of the LED chips 40. Its horizontal section, welded to the bottom of the main body 31, can quickly conduct away the heat generated during operation, reducing the operating temperature of the LED chip 40, maintaining the stability of the LED packaging structure, and extending its service life.

[0022] Specifically, the LED chip 40 is a flip chip. The electrodes 41 of the LED chip 40 are electrically connected to the metal layer 32 via a first solder paste 70. The LED chips 40 are uniformly arranged on the main substrate 10, and the number of LED chips 40 is 4-8. By adjusting the electrical connection between several LED chips 40, different circuits can be realized, such as several LED chips 40 connected in series, several LED chips 40 connected in parallel, several LED chips 40 independently controlled, and some connected in series and some in parallel, to meet different application requirements. It can be understood that the number of metal layers 32 is matched with the number of electrodes 41 of the LED chips to achieve good electrical connection of the LED chips 40.

[0023] In some embodiments, such as Figure 3 , Figure 4 and Figure 14 As shown, the LED packaging structure includes four light-emitting units. The main body 31 has four sides. Four LED chips 40 are respectively attached to the front, rear, left, and right sides of the connecting component 30. Each LED chip 40 has two electrodes 41, and each electrode 41 is electrically connected to the metal layer 32 via a first solder paste 70. In other embodiments, such as... Figure 5 As shown, the LED packaging structure includes five light-emitting units, the main body 31 of the component has five sides, and five LED chips 40 are respectively attached to the five sides of the connecting component 30. Each LED chip 40 has two electrodes 41, and each electrode 41 is electrically connected to the metal layer 32 through the first solder paste 70.

[0024] Optionally, the metal layer 32 may be made of one or more of copper, aluminum, and iron. The melting point of the first solder paste 70 is 200℃-230℃, and the raw materials for preparing the first solder paste 70 include a tin-copper alloy and flux, wherein the tin-copper alloy includes, but is not limited to, Sn. 99.3 Cu 0.7 The flux can be a high-viscosity flux, and this application does not specifically limit it. It is worth noting that the amount of tin-copper alloy and flux can be referenced from existing designs.

[0025] Furthermore, the connecting component 30 is welded and fixed to the transition substrate 20. Specifically, the component body 31 and the metal layer 32 are both welded and fixed to the transition substrate 20 using a second solder paste (not shown in the figure), the melting point of which is 230℃-250℃. The first solder paste 70 and the second solder paste have different melting points. Using first solder paste 70 and second solder paste with different melting points can avoid secondary melting of the second solder paste during welding and fixing, which would affect the bonding strength between the connecting component 30 and the transition substrate 20.

[0026] Optionally, the main body 31 of the component is made of a material with high reflectivity, such as white EMC plastic, white ceramic, etc. The raw materials for preparing the second solder paste include a tin-antimony alloy and flux, wherein the tin-antimony alloy includes, but is not limited to, Sn. 0.9 Sb 0.1 It is worth noting that the amounts of tin-antimony alloys and flux can be referenced from existing designs.

[0027] Preferably, the transition substrate 20 and the main substrate 10 are fixed by soldering with first solder paste 70.

[0028] Furthermore, the length of the transition substrate 20 is greater than the length of the connecting component 30, which can support the LED chip 40 to a certain extent and work in conjunction with the metal layer 32 to fix the LED chip 40, reducing the risk of the LED chip 40 falling off. It should be noted that the length of the connecting component 30 refers to the total length of the component body 31 after it is fitted with the metal layer 32.

[0029] Furthermore, such as Figure 8As shown, the length of the transition substrate 20 is L1, the length of the connecting component 30 is L2, and the thickness of the LED chip 40 is L3, satisfying 0.6L3≤L1-L2≤L3. If the extension length of the transition substrate 20 on the side of the LED is too long, it will block the light emission of the LED chip 40 and reduce the emission angle. It can be understood that the length L1 of the transition substrate 20 and the length L2 of the connecting component 30 can be reasonably adjusted according to the dimensions of the LED packaging structure and the dimensions of the LED chip. In some embodiments, the thickness L3 of the LED chip 40 is 150μm-250μm. Exemplary L3 can be 150μm, 175μm, 200μm, 225μm, or 250μm, but is not limited to these.

[0030] Optionally, the thickness of the fluorescent adhesive layer 50 along the horizontal direction is H. Within the conventional selection range for those skilled in the art, the thickness H of the fluorescent adhesive layer 50 has a relatively weak impact on the light-emitting effect of the LED chip 40. Its thickness H can be reasonably set according to the dimensions of the LED packaging structure and the LED chip. More preferably, 3L³ ≤ H ≤ 5L³.

[0031] Further, please refer to Figure 9 and Figure 10 The LED packaging structure also includes a white adhesive layer 60, which is disposed on the fluorescent adhesive layer 50. The white adhesive layer 60 can block the light from the LED and further reflect the light emitted from the side of the LED chip 40 back, changing the direction of light propagation, further expanding the overall light emission angle of the LED, increasing the uniformity of light emission, reducing light spots and dark areas, and improving light quality. At the same time, the white adhesive layer 60 has good insulation properties, ensuring the electrical safety of the LED packaging.

[0032] Furthermore, the thickness of the white adhesive layer 60 is 50μm-200μm, which can serve as a protective layer to prevent external physical damage and improve the mechanical strength and reliability of the LED package. For example, the thickness of the white adhesive layer 60 can be 50μm, 80μm, 100μm, 120μm, 140μm, 160μm, 180μm, or 200μm, but is not limited thereto; more preferably, the thickness of the white adhesive layer 60 is 100μm-200μm.

[0033] Accordingly, a second aspect of the present invention provides a packaging method for the LED packaging structure, comprising the following steps: (1) Fix the transition substrate 20 to the connecting component 30, wherein the connecting component 30 includes a component body 31 and a plurality of metal layers 32 disposed on the surface of the component body 31; (2) A first solder paste 70 is provided on the side of the metal layer 32, and the LED chip 40 is fixed to the surface of the metal layer 32 so that the light emission direction of the LED chip 40 is horizontal, thus obtaining a semi-finished product. (3) Provide a main substrate 10 and fix the semi-finished product to the main substrate 10; (4) A fluorescent adhesive layer 50 is provided on the main substrate 10 to cover the semi-finished product.

[0034] The following provides a detailed explanation of each step; please refer to [link / reference]. Figures 11-16 : Regarding step (1), the transition substrate 20 is fixed to the connecting component 30. The connecting component 30 includes a component body 31 and a plurality of metal layers 32 disposed on the surface of the component body 31. Preferably, please refer to Figure 11 The transition substrate 20 and the connecting component 30 have matching cutout portions 33, which can be used to achieve precise positioning between the transition substrate 20 and the connecting component 30, and can also be used to fix the transition substrate 20 and the connecting component 30, facilitating the subsequent fixing operation of the LED chip 40. The cutout portions 33 can be located at the center of the transition substrate 20 and the connecting component 30.

[0035] This step specifically includes: applying a second solder paste to the transition substrate 20, then placing the connecting component 30 on the transition substrate 20 such that the cutout portion 33 of the connecting component 30 is opposite to the cutout portion 33 of the transition substrate 20, and finally performing high-temperature heat treatment to form a stable solder joint between the transition substrate 20 and the connecting component 30 through the second solder paste.

[0036] Optionally, the second solder paste can be applied by means of spot coating, and the high-temperature heat treatment can be performed by placing the transition substrate 20 on which the connecting component 30 is placed in a high-temperature reflow oven for high-temperature soldering. The specific temperature and time can be reasonably adjusted according to the actual situation, and this application does not make specific limitations in this regard.

[0037] Optionally, the transition substrate 20 may be one or more of a ceramic substrate, a BT substrate, and an FR-4 substrate.

[0038] Regarding step (2), the LED chip 40 is fixed to the surface of the metal layer 32 so that the light emission direction of the LED chip 40 is horizontal, thus obtaining a semi-finished product; This step specifically includes: (21) Place the connecting component 30 and the transition substrate 20 onto the positioning device 80; Specifically, please refer to Figure 12The positioning device 80 includes a rotating disk 81 and positioning pins 82. The rotating disk 81 is provided with positioning pins 82 that are adapted to the connecting component 30 and the transition substrate 20. After the connecting component 30 and the transition substrate 20 are placed on the rotating disk 81, the hollow portions 33 of the connecting component 30 and the transition substrate 20 are made to engage with the positioning pins 82 on the rotating disk 81, allowing the positioning pins 82 to pass through three hollow portions 33 simultaneously, thereby fixing the connecting component 30 and the transition substrate 20. (See also...) Figure 13 .

[0039] Optionally, the cutout portion 33 may be located at the center of the rotating disk 81.

[0040] (22) Apply a first solder paste 70 to the vertical section of the L-shaped metal sheet; Specifically, taking an example where four LED chips 40 are arranged on an L-shaped metal sheet, the first solder paste 70 can be applied to the first side of the L-shaped metal sheet first. Then, by rotating the rotating disk 81, the first solder paste 70 can be applied to the second side of the L-shaped metal sheet. Next, by rotating the rotating disk 81, the first solder paste 70 can be applied to the third side of the L-shaped metal sheet. Finally, by rotating the rotating disk 81, the first solder paste 70 can be applied to the fourth side of the L-shaped metal sheet. Please refer to [link to relevant documentation]. Figure 14 .

[0041] Optionally, the coating method of the first solder paste 70 may include, but is not limited to, spin coating. The specific process parameters of spin coating may be reasonably adjusted according to the actual situation, and this application does not make specific limitations in this regard.

[0042] (23) The LED chip 40 is bonded to the vertical surface of the L-shaped metal layer 32 so that the light emission direction of the LED chip 40 is horizontal, and a semi-finished product is obtained; Specifically, LED chip 40 is attached to the first side and die-bonded; then, rotating the rotating disk 81, LED chip 40 is attached to the second side and die-bonded; next, rotating the rotating disk 81, LED chip 40 is attached to the third side and die-bonded; finally, rotating the rotating disk 81, LED chip 40 is attached to the fourth side and die-bonded. Please refer to [link to relevant documentation]. Figure 15 In some embodiments, die bonding can be performed on the entire assembly after all four LED chips 40 have been attached.

[0043] Optionally, the die bonding process can be horizontal die bonding.

[0044] Regarding step (3), a main substrate 10 is provided, and the semi-finished product is fixed to the main substrate 10; This step specifically includes: A first solder paste 70 is applied to the main substrate 10. The semi-finished product is then removed from the positioning device 80 and placed on the main substrate 10. Finally, a high-temperature heat treatment is performed to ensure a stable solder joint between the main substrate 10 and the transition substrate 20 through the first solder paste 70. (See also...) Figure 16 .

[0045] Optionally, the coating method of the first solder paste 70 includes, but is not limited to, dot coating. The high-temperature heat treatment may involve placing the main substrate 10 with the semi-finished product on it in a high-temperature reflow oven for high-temperature soldering. The specific temperature and time can be reasonably adjusted according to the actual situation, and this application does not impose specific limitations on this. Through this high-temperature soldering, the soldering strength between the LED chip 40 and the metal layer 32, as well as between the transition substrate 20 and the connecting component 30, can be further improved.

[0046] Regarding step (4), a fluorescent adhesive layer 50 is disposed on the main substrate 10 to cover the semi-finished product; This step specifically includes: using a molding process to mold a phosphor layer 50 onto the semi-finished product, thereby obtaining a phosphor layer 50 on the main substrate 10, and covering the LED chip 40, the surface of the connecting component 30, and the side surface of the transition substrate 20. Please refer to [link to relevant documentation]. Figure 3 and Figure 4 .

[0047] It is understandable that the raw materials used to prepare the fluorescent adhesive layer 50 include phosphors, which can be combined with the light emitted by the LED chip 40 to form white light.

[0048] In some embodiments, the packaging method of the LED packaging structure further includes the following steps: (5) A white adhesive layer 60 is provided on the fluorescent adhesive layer 50; This step specifically includes: using a molding process to mold a white adhesive layer 60 onto the fluorescent adhesive layer 50, so that the white adhesive layer 60 is disposed on the fluorescent adhesive layer 50. Please refer to [link to relevant documentation]. Figure 9 and Figure 10 .

[0049] Accordingly, this embodiment also provides an LED backlight module, which includes the aforementioned LED packaging structure.

[0050] Compared with traditional LED backlight modules, the LED packaging structure used in this invention expands the light emission angle and avoids the use of lens 110 in traditional LED backlight modules, making the LED backlight module thinner, effectively reducing costs, and facilitating a lighter and thinner backlight module design. On the other hand, it reduces the number of LED chips 40 used, eliminates uneven brightness, and improves the visual effect of the backlight module.

[0051] The present invention will be further described below with reference to specific embodiments: Example 1 This embodiment provides an LED packaging structure, including: a main substrate and four light-emitting units, each light-emitting unit having a transition substrate, a connecting component, an LED chip, and a phosphor layer; A transition substrate is disposed between the main substrate and the connecting component. The connecting component includes a component body and a metal layer disposed on the surface of the component body. The component body has four sides, and the metal layer has eight LED chips, four of which are respectively attached to the four sides of the component body. The metal layer is an L-shaped metal sheet, which is nested and fitted with the component body. The vertical section of the L-shaped metal sheet is attached to the side wall of the component body, and the horizontal section of the L-shaped metal sheet is welded and fixed to the bottom of the component body. The LED chips are attached to the side of the metal layer opposite to the component body, and the light emission direction of the LED chips is horizontal. A cutout is formed between the light emission units to expose the main substrate. A phosphor layer is disposed on the main substrate and covers the LED chips, the surface of the connecting component, and the sides of the transition substrate, and fills the cutout.

[0052] The length of the transition substrate is L1, the length of the connecting component is L2, and the thickness of the LED chip is L3, satisfying L1-L2=0.8L3.

[0053] Accordingly, this embodiment provides a packaging method for an LED packaging structure, including the following steps: (1) Fix the transition substrate to the connecting component, the connecting component including the component body and 8 metal layers disposed on the surface of the component body; The soldering and fixing process utilizes a second solder paste with a melting point of 240°C. The raw materials for preparing the second solder paste include Sn. 0.9 Sb 0.1 and flux; (2) Apply the first solder paste to the side of the metal layer, fix the LED chip to the surface of the metal layer, and make the light emission direction of the LED chip horizontal to obtain a semi-finished product; In this configuration, the electrodes of each LED chip are electrically connected to the metal layer via a first solder paste, the melting point of which is 210°C; the raw material for preparing the first solder paste is Sn. 99.3 Cu 0.7 And flux.

[0054] (3) Provide a main substrate and fix the semi-finished product to the main substrate; The first solder paste is used for soldering and fixing.

[0055] (4) A fluorescent adhesive layer is set on the main substrate to cover the semi-finished product.

[0056] Accordingly, this embodiment also provides an LED backlight module, including an LED packaging structure.

[0057] Example 2 This embodiment provides an LED packaging structure, which differs from Embodiment 1 in that: An LED packaging structure includes: a main substrate and 5 light-emitting units, i.e., 5 LED chips are set. The main body of the component has five sides and 10 metal layers. The 5 LED chips are respectively attached to the five sides of the main body of the component.

[0058] It was prepared using the preparation method described in Example 1.

[0059] Accordingly, this embodiment also provides an LED backlight module, including an LED packaging structure.

[0060] Example 3 This embodiment provides an LED packaging structure, which differs from Embodiment 1 in that: The LED packaging structure also includes a white glue layer, which is placed on the fluorescent glue layer and has a thickness of 120μm.

[0061] Accordingly, the preparation method also includes: (5) Set a white glue layer on the fluorescent glue layer; Accordingly, this embodiment also provides an LED backlight module, including an LED packaging structure.

[0062] Comparative Example 1 This comparative example provides an LED packaging structure, which differs from Example 1 in that: The length of the transition substrate is L1, the length of the connecting component is L2, and the thickness of the LED chip is L3, satisfying L1-L2=0.3L3.

[0063] Comparative Example 2 This comparative example provides an LED packaging structure, the structure of which is as follows: Figure 1 As shown, it specifically includes: an LED chip, a support frame surrounding the LED chip, and fluorescent adhesive filling the support frame and encapsulating the LED chip.

[0064] This control group also provides an LED backlight module, including the aforementioned conventional LED packaging structure, substrate, lens, and diffuser. The LED packaging structure is fixed on the substrate and electrically connected to the substrate via wires. The lens covers the LED packaging structure, and the diffuser is located above the LED packaging structure. Its schematic diagram is shown below. Figure 2 As shown.

[0065] Performance testing 1. Light intensity distribution: The light intensity distribution of the LED backlight modules obtained in the examples and comparative examples was tested. The light intensity distribution test range was -90° to 90°, and the corresponding light intensity distribution curve was plotted with the light emission angle as the abscissa and the relative light intensity as the ordinate.

[0066] Test results are available Figures 17-21 ,in, Figures 17-19 The light intensity distribution curves of the LED backlight modules obtained in Examples 1-3 show that the light emission angle can reach about 170°. Figure 20 The light intensity distribution curve of the LED backlight module obtained in Comparative Example 1 shows that the light emission angle is only 120°. Figure 21 The image shows the light intensity distribution curve of the LED backlight module obtained in Comparative Example 2, with a light emission angle of only 100°. Figures 17-21 Comparative analysis shows that the LED chip is placed on the outside of the metal layer in this application, which changes the traditional vertical light emission method and makes the light emission direction horizontal. This can effectively improve the light emission angle of the LED chip. Furthermore, the length of the transition substrate can be selected to further improve the light emission angle and reduce the use of lenses.

[0067] 2. Light mixing uniformity: The LED backlight modules obtained in Example 3 and Comparative Example 2 were tested.

[0068] Test results are available Figure 22 and Figure 23 ,in, Figure 22 This is a rendering of Example 3. Figure 23 This is the effect diagram for Comparative Example 2. The comparison reveals that... Figure 22 The light intensity at the edge of the LED chip is close to that at the top, resulting in uniform light output from the LED backlight module. Figure 23 The light intensity is strong directly above the LED chip and weak at the edges, resulting in alternating bright and dark areas and obvious uneven light mixing. Therefore, this application addresses this issue by placing the LED chip outside the metal layer, changing the traditional vertical light emission method to a horizontal light emission direction, which increases the uniformity of light emission.

[0069] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. An LED packaging structure, characterized in that, include: The main substrate and at least two light-emitting units, wherein the light-emitting unit includes a transition substrate, a connecting component, an LED chip, and a phosphor layer; The transition substrate is disposed between the main substrate and the connecting component. The connecting component includes a component body and several metal layers disposed on the surface of the component body. The LED chip is attached to the metal layers and arranged around the connecting component. The light emission direction of the LED chip is horizontal. A cutout is formed between the light-emitting units to expose the transition substrate or the main substrate. The phosphor layer is disposed on the main substrate and covers the LED chip, the surface of the connecting component and the side of the transition substrate, and fills the cutout. The metal layer is an L-shaped metal sheet, which is nested with the main body of the component. The vertical section of the L-shaped metal sheet is attached to the side wall of the main body of the component, and the horizontal section of the L-shaped metal sheet is welded and fixed to the bottom of the main body of the component. The LED chip is attached to the side of the metal layer opposite to the main body of the component; The connecting component is welded and fixed to the transition substrate; the length of the transition substrate is greater than the length of the connecting component.

2. The LED packaging structure as described in claim 1, characterized in that, The length of the transition substrate is L1, the length of the connecting component is L2, and the thickness of the LED chip is L3, satisfying 0.6L3≤L1-L2≤L3.

3. The LED packaging structure as described in claim 1, characterized in that, The LED chip is a flip chip, and the electrodes of the LED chip are electrically connected to the metal layer through a first solder paste; the transition substrate and the main substrate are soldered and fixed together through the first solder paste. The melting point of the first solder paste is 200℃-230℃; wherein, the raw materials for preparing the first solder paste include tin-copper alloy and flux.

4. The LED packaging structure as described in claim 1, characterized in that, The connecting component is fixed to the transition substrate by soldering with a second solder paste; The melting point of the second solder paste is 230℃-250℃; wherein, the raw materials for preparing the second solder paste include tin-antimony alloy and flux.

5. The LED packaging structure as described in claim 1, characterized in that, The LED encapsulation structure further includes a white adhesive layer, which is disposed on the fluorescent adhesive layer; The thickness of the white glue layer is 100μm-200μm.

6. The LED packaging structure as described in claim 1, characterized in that, The LED chips are evenly arranged on the main substrate, and the number of LED chips is 4-8.

7. A packaging method for an LED packaging structure as described in any one of claims 1-6, characterized in that, Includes the following steps: The transition substrate is fixed to the connecting component, the connecting component including a component body and several metal layers disposed on the surface of the component body; The LED chip is fixed to the surface of the metal layer, so that the light emission direction of the LED chip is horizontal, to obtain a semi-finished product; A main substrate is provided, and the semi-finished product is fixed to the main substrate; A fluorescent adhesive layer is deposited on the main substrate to cover the semi-finished product.

8. An LED backlight module, characterized in that, Includes the LED packaging structure as described in any one of claims 1-6.

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