LED chip scale packaging structure, preparation method and backlight display module

Abstract

The invention discloses an LED chip scale packaging structure, a preparation method and a backlight display module, and relates to the technical field of photoelectric devices. The LED lamp specifically comprises a conductive substrate and an LED chip electrically connected to the conductive substrate. The fluorescent film layer is attached and coated on the light emitting surface and the side wall of the LED chip; the transparent sealing colloid covers the outer surface of the fluorescent film layer, and the edge of the transparent sealing colloid extends to the conductive substrate on the peripheral side of the chip and forms a sealing connection structure; the transparent sealing colloid is matched with the conductive substrate to form a closed space, and the fluorescent film layer is packaged in the closed space in an airtight mode. According to the invention, the fluorescent film layer is matched with the transparent colloid sealed on the ground, so that the erosion path of water vapor to the KSF fluorescent powder is blocked, the problem of hydrolysis degradation of the fluorescent powder in a high-temperature and high-humidity environment is solved, and the reliability of the device is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic device technology, and in particular to an LED chip-level packaging structure, preparation method, and backlight display module. Background Technology

[0002] NCSP (Nano Scale Chip Scale Package), as a chip-level packaged device, occupies a significant share in the LED backlight display field due to its advantages such as small size and wide emission angle. As the market demands higher display quality, packaged LED chips are required to not only possess excellent optical performance but also maintain extremely high reliability in complex environments.

[0003] Currently, in existing technologies, EMC flat panel brackets are used as brackets to manufacture NCSP LED chips. A die bonder is mainly used to arrange the LED chips in an array on the bracket. Then, red phosphor (such as KSF) and green phosphor are mixed with adhesive and directly applied to the chips through a molding process. After the chips cure, a five-sided light-emitting package structure is formed.

[0004] However, the aforementioned existing technologies have the following obvious drawbacks in practical applications. On the one hand, existing mixed phosphor molding methods are difficult to form a dense and completely moisture-proof protective layer around the phosphor particles. KSF (potassium fluorosilicate) phosphors are extremely sensitive to moisture. When exposed to high temperature and high humidity environments, such as during the double 85 test, water molecules in the air can easily permeate through the colloid and undergo an irreversible hydrolysis reaction with KSF (chemical formula: K2SiF6+4H2O→2KF+H4SiO4+4HF). This not only leads to a sharp decrease in the brightness of the LED beads and severe color point drift, but the generated acidic substances can also corrode the chip electrodes.

[0005] Therefore, this application aims to solve the reliability problem of KSF phosphor deterioration and failure due to moisture intrusion in high temperature and high humidity environments, and the problem that the generated products affect the reliability of the LED beads. Summary of the Invention

[0006] The main objective of this invention is to provide an LED chip-level packaging structure, preparation method, and backlight display module. The aim is to effectively solve the hydrolysis and degradation problem of KSF phosphor under high temperature and high humidity environments through a special packaging structure design, thereby significantly improving the reliability of the device.

[0007] To achieve the above objectives, the present invention proposes an LED chip-level packaging structure, comprising: Conductive substrate; LED chip, wherein the LED chip is electrically connected to the conductive substrate; A fluorescent film layer, which is adhered to and covers the light-emitting surface and sidewalls of the LED chip; and A transparent sealing colloid covers the outer surface of the fluorescent film layer, the edge of the transparent sealing colloid extends and covers the conductive substrate around the LED chip, and is connected to the conductive substrate; The transparent sealing colloid and the conductive substrate enclose a sealed space, which is used to encapsulate the fluorescent film layer.

[0008] Furthermore, it also includes a first colloid, which is disposed around the periphery of the LED chip and connected to the conductive substrate; The bottom edge of the fluorescent film extends and connects to the surface of the first colloid away from the conductive substrate.

[0009] Furthermore, the height of the first colloid is lower than the height of the LED chip; The light-emitting surface and a portion of the sidewall of the LED chip are located outside the first adhesive layer and are encapsulated within the fluorescent film layer.

[0010] Furthermore, the edge of the transparent sealing colloid extends to the surface of the first colloid away from the conductive substrate and is sealed to the first colloid. The fluorescent film layer is encapsulated within a closed space formed by the transparent sealing colloid and the first colloid.

[0011] Furthermore, it also includes a second colloid, which is stacked on the surface of the transparent sealing colloid away from the conductive substrate; the outer sidewall of the second colloid, the outer sidewall of the transparent sealing colloid, and the outer sidewall of the first colloid are coplanar.

[0012] Furthermore, the conductive substrate includes positive and negative electrode sheets arranged at intervals between each other; The LED chip is disposed between the positive electrode and the negative electrode, with the positive terminal of the LED chip electrically connected to the positive electrode and the negative terminal of the LED chip electrically connected to the negative electrode. The transparent sealing colloid fills the gap between the positive electrode and the negative electrode.

[0013] Furthermore, the top surface of the first colloid defines a stepped structure, and the bottom edge of the fluorescent film layer overlaps the stepped structure; The transparent sealing colloid covers the joint between the stepped structure and the fluorescent film layer.

[0014] Furthermore, both the first colloid and the second colloid are white colloids with a reflectivity greater than 80%, and the transparent sealing colloid is a transparent silicone with a refractive index greater than 1.4; the second colloid is used to reflect the light escaping from the top surface of the transparent sealing colloid to adjust the light emission angle of the encapsulation structure.

[0015] This application also discloses a method for fabricating the LED chip-level packaging structure as described above, comprising the following steps: Step S1: Provide a conductive substrate array plate, the conductive substrate array plate including a support and a plurality of conductive substrates arranged in an array on the support; Step S2: Solder the LED chips onto the respective conductive substrates; Step S3: Form a first colloid surrounding the conductive substrate around the LED chip, and control the height of the first colloid to be lower than the light-emitting surface of the LED chip. Step S4: Cover the LED chip and the first colloid with a fluorescent film layer, soften the fluorescent film layer by vacuum heating and coat the light-emitting surface, sidewalls and upper surface of the LED chip and the first colloid, and then cure and shape it. Step S5: Injection molding a transparent sealing colloid onto the outside of the fluorescent film layer and the first colloid to fill and seal the periphery of the fluorescent film layer; Step S6: Inject and mold a second colloid on top of the transparent sealant to cover the top surface of the transparent sealant; Step S7: Cut the second colloid, the transparent sealing colloid, the first colloid and the bracket vertically along the gap between each of the conductive substrates to obtain an independent LED chip-level packaging structure.

[0016] This application also discloses a backlight display module, including a circuit board and an LED chip-level packaging structure as described above, arrayed on the circuit board.

[0017] The above technical solution has the following advantages: This invention covers the outer surface of the fluorescent film layer with a transparent sealing colloid, extending the edge of the transparent sealing colloid to the conductive substrate around the LED chip. The transparent sealing colloid and the conductive substrate work together to form a closed space. Combined with the high density of the molding process, this blocks the path of moisture from the external environment to penetrate into the fluorescent film layer from the top, side and bottom interfaces. This effectively prevents the KSF phosphor from undergoing hydrolysis in high temperature and high humidity environments, avoiding brightness decay, color point drift and electrode corrosion caused by hydrolysis. It effectively solves the problem of hydrolysis and degradation of KSF phosphor in high temperature and high humidity environments, and significantly improves the reliability of the device.

[0018] By placing a first colloid around the LED chip and connecting the bottom edge of the phosphor film layer to the surface of the first colloid away from the conductive substrate, the risk of stress concentration or breakage caused by the suspension of the phosphor film layer during bonding is effectively solved by using the first colloid as a supporting dam. Simultaneously, the first colloid is a high-reflectivity white colloid, which can reflect the light emitted laterally from the LED chip upwards into the phosphor film layer, reducing bottom light loss and significantly improving the overall light output brightness of the encapsulation structure.

[0019] By layering a second colloid on top of a transparent sealing colloid, and ensuring that the sidewalls of all colloids are coplanar, the second colloid, acting as a top light-blocking or reflective layer, can effectively adjust the light emission angle of the device. Furthermore, the coplanar sidewall structure corresponds to the cutting process after board-level molding, improving production efficiency and product dimensional consistency. Attached Figure Description

[0020] The present invention will now be described in detail with reference to specific embodiments and accompanying drawings, wherein: Figure 1 This is a structural diagram of the LED unit of the present invention; Figure 2 This is a structural diagram of step S1 of the present invention; Figure 3 This is a structural diagram of step S2 of the present invention; Figure 4 This is a structural diagram of step S3 of the present invention; Figure 5 This is a structural diagram of the fluorescent film layer in step S4 of the present invention; Figure 6 This is a structural diagram of the softening of the fluorescent film layer in step S4 of the present invention; Figure 7 This is a structural diagram of step S5 of the present invention; Figure 8 This is a structural diagram of step S6 of the present invention; Figure 9 This is a structural diagram of step S7 of the present invention; Figure 10 This is a flowchart of the method of the present invention.

[0021] In the picture: 100, Conductive substrate; 101, Positive electrode; 102, Negative electrode; 200, First colloid; 300, LED chip; 400, Fluorescent film layer; 500, Transparent sealing colloid; 600, Second colloid; 700, Support; 800, LED unit. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the invention and do not constitute a limitation thereof.

[0023] In the field of optoelectronic device packaging, especially for high color gamut backlight display applications, KSF (potassium fluorosilicate) phosphor is widely used due to its narrow half-width characteristic. However, those skilled in the art know that KSF phosphor has significant chemical stability defects and is extremely sensitive to moisture. In high temperature and high humidity environments (e.g., 85 degrees Celsius / 85% relative humidity), water molecules can penetrate traditional encapsulating colloids and undergo a hydrolysis reaction with KSF (chemical formula: K2SiF6 + 4H2O → 2KF + H4SiO4 + 4HF). This not only leads to the destruction of the phosphor lattice, causing degradation of brightness and color, but its byproduct, hydrofluoric acid (HF), is also highly corrosive, eroding the chip electrodes and substrate plating, ultimately leading to open circuits or functional failure of the device.

[0024] Existing encapsulation technologies typically involve mixing KSF phosphor with silicone and then dispensing or molding the mixture. However, due to the presence of micropores within the cured colloid and the limited interfacial bonding between the colloid and the substrate, an effective moisture barrier layer cannot be formed. Therefore, this application proposes an LED chip-level encapsulation structure designed to construct a physically closed-loop microscopic enclosed space to block the contact path between external moisture and the internal phosphor material.

[0025] in, Figures 2 to 9 Each view includes a top view and a sectional view, used to illustrate the two-dimensional positional relationships of different steps.

[0026] like Figure 1 As shown, this embodiment provides an LED chip-level packaging structure. The structure mainly includes a conductive substrate 100, an LED chip 300, a phosphor film layer 400, and a transparent sealing colloid 500. The LED chip is electrically connected to the conductive substrate. The phosphor film layer 400 is adhered to and covers the light-emitting surface and sidewalls of the LED chip 300. The transparent sealing colloid 500 covers the outer surface of the phosphor film layer. The edge of the transparent sealing colloid 500 extends and covers the conductive substrate 100 surrounding the LED chip 300, and is connected to the conductive substrate 100. The transparent sealing colloid 500 and the conductive substrate 100 enclose a closed space, which is used to encapsulate the phosphor film layer 400.

[0027] The conductive substrate 100 serves as the electrical connection and heat dissipation base for the device. The LED chip 300 is electrically connected to the conductive substrate 100. The specific connection method can be flip-chip bonding technology, which uses eutectic bonding or gold-tin bonding to directly bond the electrodes of the LED chip 300 to the conductive substrate 100 to reduce thermal resistance.

[0028] The fluorescent film layer 400 is a film material with a fixed thickness and phosphor concentration, rather than a traditional fluid fluorescent adhesive. The fluorescent film layer 400 is bonded and coated onto the light-emitting surface and sidewalls of the LED chip 300 through a vacuum hot-pressing process, which makes the phosphor distribution uniformity better than the dispensing process. Furthermore, the film layer has a higher density due to pre-calendering.

[0029] A transparent sealing colloid 500 covers the outer surface of the fluorescent film layer 400. It should be noted that the transparent sealing colloid 500 is a structural sealant. The edge of the transparent sealing colloid 500 extends and covers the conductive substrate 100 around the LED chip 300, forming a sealed connection structure with the conductive substrate 100. The bottom edge of the transparent sealing colloid 500 is tightly bonded to the substrate.

[0030] The transparent sealing colloid 500 and the conductive substrate 100 work together to form a closed space, within which the fluorescent film layer 400 is hermetically sealed. For moisture in the external environment to contact the fluorescent film layer 400, it must either penetrate the dense transparent sealing colloid 500 or disrupt the interfacial bonding between the transparent sealing colloid 500 and the conductive substrate 100, thus significantly extending the moisture penetration path.

[0031] like Figure 1 As shown, based on the above embodiment, the encapsulation structure further includes a first colloid 200, which is disposed around the periphery of the LED chip 300 and connected to the conductive substrate 100. The bottom edge of the fluorescent film layer 400 extends and is connected to the surface of the first colloid 200 away from the conductive substrate 100.

[0032] In this embodiment, the first colloid 200 is mainly used to fill the bottom, similar to a dam. The bottom edge of the fluorescent film layer 400 extends and connects to the surface of the first colloid 200 away from the conductive substrate 100. Specifically, since the fluorescent film layer 400 has a certain rigidity, if the fluorescent film layer 400 is directly attached to the plane of the LED chip 300, stress concentration or suspension will occur at the bottom corner of the LED chip 300. In this embodiment, after filling with the first colloid 200, the edge of the fluorescent film layer 400 can smoothly overlap the top surface of the first colloid 200, playing a supporting role.

[0033] like Figure 1 As shown, in order to ensure light efficiency, the height of the first colloid 200 is limited. The height of the first colloid 200 is lower than the height of the LED chip 300. The light-emitting surface and part of the sidewall of the LED chip 300 are located outside the first colloid 200 and are covered by the fluorescent film layer 400.

[0034] Specifically, the light-emitting surface of the LED chip 300 is the side of the LED chip 300 away from the conductive substrate 100. The upper region of the light-emitting surface and sidewalls of the LED chip 300 is located outside the first colloid 200 and is encapsulated within the phosphor film layer 400. This ensures that the main light-emitting surface of the LED chip 300 can directly couple into the phosphor film layer 400 for light color conversion, while the first colloid 200 only covers the lower electrode area of ​​the chip, thus providing support while avoiding blocking effective light.

[0035] like Figure 1 As shown, the edge of the transparent sealing colloid 500 extends to the surface of the first colloid 200 away from the conductive substrate 100 and is sealed to the first colloid 200; the fluorescent film layer 400 is encapsulated in the closed space formed by the transparent sealing colloid 500 and the first colloid 200.

[0036] In this embodiment, the first colloid 200 is also a dense material. The first colloid 200 and the upper transparent sealing colloid 500 together form a protective barrier, preventing moisture from penetrating from the side, as the side is blocked by the first colloid 200; moisture also cannot penetrate from the top, as the top is blocked by the transparent sealing colloid 500; and the bonding interface between the first colloid 200 and the transparent sealing colloid 500 achieves molecular-level bonding through a molding process, further reducing the passage path of moisture.

[0037] A first colloid 200 is disposed around the LED chip 300, and the bottom edge of the phosphor film layer 400 is connected to the surface of the first colloid 200 facing away from the conductive substrate 100. Using the first colloid 200 as a supporting dam effectively solves the risk of stress concentration or breakage of the phosphor film layer 400 due to suspension during the bonding process. Simultaneously, the first colloid 200 is preferably a high-reflectivity white colloid, which can reflect the light emitted laterally from the LED chip 300 upwards into the phosphor film layer 400, reducing bottom light loss and significantly improving the overall light output brightness of the encapsulation structure.

[0038] like Figure 1 As shown, this application also includes a second colloid 600, which is stacked on the surface of the transparent sealing colloid 500 away from the conductive substrate 100; the outer sidewalls of the second colloid 600, the outer sidewalls of the transparent sealing colloid 500, and the outer sidewalls of the first colloid 200 are coplanar.

[0039] Specifically, such as Figure 9 As shown, this encapsulation structure is obtained by first forming each layer of colloid sequentially on the support 700, and then separating them by vertical cutting along a preset cutting path using a cutting blade. Therefore, the sidewalls of each colloid layer naturally form a smooth and continuous coplanar structure at the cutting surface, without obvious steps or misalignments, ensuring the uniformity of each LED chip unit 800.

[0040] like Figure 1 As shown, the conductive substrate 100 includes a positive electrode 101 and a negative electrode 102 spaced apart from each other; an LED chip 300 is disposed between the positive electrode 101 and the negative electrode 102, with the positive terminal of the LED chip 300 electrically connected to the positive electrode 101 and the negative terminal of the LED chip 300 electrically connected to the negative electrode 102; and a transparent sealing colloid 500 is filled in the gap between the positive electrode 101 and the negative electrode 102.

[0041] The positive electrode 101 and the negative electrode 102 can be part of an etched lead frame or independent pads on a PCB board. The LED chip 300 is positioned between the positive electrode 101 and the negative electrode 102. The positive terminal of the LED chip 300 is electrically connected to the positive electrode 101, and the negative terminal is electrically connected to the negative electrode 102. For flip-chip LED chips 300, their positive and negative electrodes are directly soldered to the corresponding positive electrode 101 and negative electrode 102.

[0042] like Figure 1 As shown, the transparent sealing colloid 500 fills the gap between the positive electrode 101 and the negative electrode 102. If the first colloid 200 is formed by fluid dispensing, the gap may be filled by the first colloid 200 first; however, in the molding process of this embodiment, the transparent sealing colloid 500 or the first colloid 200 under high pressure will fully fill the tiny electrode gap between the positive electrode 101 and the negative electrode 102, preventing creepage or short circuits, while enhancing the mechanical strength of the substrate.

[0043] like Figure 1 , Figure 6 and Figure 7 As shown, the top surface of the first colloid 200 defines a stepped structure, and the bottom edge of the fluorescent film layer 400 overlaps the stepped structure; the transparent sealing colloid 500 covers the overlap between the stepped structure and the fluorescent film layer 400, and the top surface of the first colloid 200 defines the stepped structure. The stepped structure includes, but is not limited to, right-angled steps, and can also be a meniscus formed by the surface tension of the colloid or a concave-convex surface formed by mold pressing.

[0044] The bottom edge of the fluorescent film layer 400 overlaps the stepped structure. The transparent sealing colloid 500 covers the overlap between the stepped structure and the fluorescent film layer 400, increasing the path length for water vapor to penetrate along the interface between the first colloid 200 and the transparent sealing colloid 500. Furthermore, the stress interlocking effect at the step can prevent the colloid from delaminating at the high temperature of reflow soldering, thereby further maintaining airtightness.

[0045] This embodiment optimizes the optical properties of each colloid. Both the first colloid 200 and the second colloid 600 are white colloids with a reflectivity greater than 80%. Specifically, high reflectivity can be achieved by doping titanium dioxide (TiO2) or aluminum oxide (Al2O3) particles into the silicone or epoxy resin substrate. The first colloid 200 reflects downward-emitted light back to the fluorescent film layer, improving luminous efficiency; the second colloid 600 reflects light escaping from the top surface of the transparent sealing colloid 500 to adjust the light emission angle of the encapsulation structure, prevent lateral light leakage, and concentrate the light emitted from the top.

[0046] The transparent sealing colloid 500 is a transparent silicone with a refractive index greater than 1.4, preferably a phenyl silicone with a refractive index greater than 1.5. The high refractive index helps to reduce total reflection between the fluorescent film layer 400 and the colloid, thereby improving the light extraction efficiency.

[0047] like Figures 2 to 10 As shown, Figure 10 As shown in the overall flowchart, this application also discloses a method for fabricating an LED chip-level packaging structure, which ensures the realization of the above structure through specific process steps.

[0048] Step S1: Provide a conductive substrate array board, which includes a support 700 and multiple conductive substrates 100 arranged in an array. The support 700 can be an EMC (epoxy molding compound) support or a metal frame.

[0049] Step S2: Solder the LED chips 300 onto the corresponding conductive substrates. During this process, a flux cleaning process can be used to ensure that there are no residues at the electrode connections, so as not to affect the adhesion of the subsequent adhesive.

[0050] Step S3: Form a surrounding first colloid 200 on the conductive substrate 100 around the LED chip 300. This step can be achieved by dispensing or screen printing processes, controlling the height of the first colloid 200 to be lower than the light-emitting surface of the LED chip 300, for example, between 1 / 3 and 2 / 3 of the chip height.

[0051] Step S4: Apply the fluorescent film layer 400 over the LED chip 300 and the first colloid 200. Using a vacuum laminator, the fluorescent film layer 400 is softened at a heating temperature of 100℃-150℃. Under the combined action of vacuum negative pressure and mechanical pressure, the softened fluorescent film layer 400 deforms, tightly covering the top surface and sidewalls of the LED chip 300, while the edges of the fluorescent film layer 400 are tightly adhered to the upper surface of the first colloid 200. It is then cured to set its shape.

[0052] Step S5: A transparent sealing colloid 500 is molded onto the outside of the fluorescent film layer 400 and the first colloid 200, filling and sealing the periphery of the fluorescent film layer 400. Under high pressure with the mold closed, a liquid or semi-solid transparent colloid is injected into the mold cavity, completely filling the voids around the fluorescent film layer 400 and chemically bonding with the first colloid 200 and the conductive substrate 100. After the transparent sealing colloid 500 cures, it forms a dense colloid.

[0053] Step S6: A second adhesive 600 is molded on top of the transparent sealing adhesive 500 to cover the top surface of the transparent sealing adhesive 500. The thickness of the second adhesive 600 can be freely selected, typically to control the overall thickness of the device and form the top reflective layer.

[0054] Step S7: The second colloid 600, transparent sealing colloid 500, first colloid 200, and support 700 are vertically cut along the gaps between the conductive substrates 100 to obtain an independent LED chip-level packaging structure. Specifically, a diamond cutting wheel or laser cutting equipment is used to vertically cut the second colloid 600, transparent sealing colloid 500, first colloid 200, and support 700, so that the sidewalls of each colloid layer form flush cut surfaces at the cutting paths, ultimately forming an independent LED unit 800, which is the independent LED chip-level packaging structure of this application.

[0055] A further improvement based on the above embodiments is that, prior to step S5, the surfaces of the fluorescent film layer 400 and the first colloid 200 are preferably subjected to plasma cleaning treatment, specifically by introducing a mixture of argon and oxygen. This not only removes organic contaminants from the surface but also introduces polar groups onto the surface of the fluorescent film layer, thereby significantly enhancing the chemical bonding between the transparent sealing colloid 500 and the fluorescent film layer 400, preventing moisture intrusion due to interface delamination during the double 85 test.

[0056] This application achieves omnidirectional airtight encapsulation of the fluorescent film layer 400 by sealing the entire fluorescent film layer 400 on the conductive substrate 100 with a transparent sealing colloid 500 and, in conjunction with the stepped structure of the first colloid 200. This prevents water molecules from hydrolyzing with the fluorescent film layer 400, solves the problem of phosphor hydrolysis and degradation under high temperature and humidity conditions, and significantly improves the reliability of the device.

[0057] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An LED chip-level packaging structure, characterized in that, include: Conductive substrate; LED chip, wherein the LED chip is electrically connected to the conductive substrate; A fluorescent film layer, which is adhered to and covers the light-emitting surface and sidewalls of the LED chip; and A transparent sealing colloid covers the outer surface of the fluorescent film layer, the edge of the transparent sealing colloid extends and covers the conductive substrate around the LED chip, and is connected to the conductive substrate; The transparent sealing colloid and the conductive substrate enclose a sealed space, which is used to encapsulate the fluorescent film layer.

2. The LED chip-level packaging structure as described in claim 1, characterized in that, It also includes a first colloid, which is disposed around the periphery of the LED chip and connected to the conductive substrate; The bottom edge of the fluorescent film extends and connects to the surface of the first colloid away from the conductive substrate.

3. The LED chip-level packaging structure as described in claim 2, characterized in that, The height of the first colloid is lower than the height of the LED chip; The light-emitting surface and a portion of the sidewall of the LED chip are located outside the first adhesive layer and are encapsulated within the fluorescent film layer.

4. The LED chip-level packaging structure as described in claim 2, characterized in that, The edge of the transparent sealing colloid extends to the surface of the first colloid away from the conductive substrate and is sealed to the first colloid. The fluorescent film layer is encapsulated within a closed space formed by the transparent sealing colloid and the first colloid.

5. The LED chip-level packaging structure as described in claim 4, characterized in that, It also includes a second colloid, which is stacked on the surface of the transparent sealing colloid away from the conductive substrate; the outer sidewall of the second colloid, the outer sidewall of the transparent sealing colloid, and the outer sidewall of the first colloid are coplanar.

6. The LED chip-level packaging structure as described in claim 1, characterized in that, The conductive substrate includes positive and negative electrode plates spaced apart from each other; The LED chip is disposed between the positive electrode and the negative electrode, with the positive terminal of the LED chip electrically connected to the positive electrode and the negative terminal of the LED chip electrically connected to the negative electrode. The transparent sealing colloid fills the gap between the positive electrode and the negative electrode.

7. The LED chip-level packaging structure as described in claim 4, characterized in that, The top surface of the first colloid defines a stepped structure, and the bottom edge of the fluorescent film layer overlaps the stepped structure. The transparent sealing colloid covers the joint between the stepped structure and the fluorescent film layer.

8. The LED chip-level packaging structure as described in claim 5, characterized in that, Both the first colloid and the second colloid are white colloids with a reflectivity greater than 80%, and the transparent sealing colloid is a transparent silicone with a refractive index greater than 1.4; the second colloid is used to reflect the light escaping from the top surface of the transparent sealing colloid in order to adjust the light emission angle of the encapsulation structure.

9. A method for fabricating an LED chip-level packaging structure as described in any one of claims 1 to 8, characterized in that, Includes the following steps: Step S1: Provide a conductive substrate array plate, the conductive substrate array plate including a support and a plurality of conductive substrates arranged in an array on the support; Step S2: Solder the LED chips onto the respective conductive substrates; Step S3: Form a first colloid surrounding the conductive substrate around the LED chip, and control the height of the first colloid to be lower than the light-emitting surface of the LED chip. Step S4: Cover the LED chip and the first colloid with a fluorescent film layer, soften the fluorescent film layer by vacuum heating and coat the light-emitting surface, sidewalls and upper surface of the LED chip and the first colloid, and then cure and shape it. Step S5: Injection molding a transparent sealing colloid onto the outside of the fluorescent film layer and the first colloid to fill and seal the periphery of the fluorescent film layer; Step S6: Inject and mold a second colloid on top of the transparent sealant to cover the top surface of the transparent sealant; Step S7: Cut the second colloid, the transparent sealing colloid, the first colloid and the bracket vertically along the gap between each of the conductive substrates to obtain an independent LED chip-level packaging structure.

10. A backlight display module, characterized in that, The LED chip-level packaging structure as described in any one of claims 1 to 8 includes a circuit board and an array disposed on the circuit board.

Images