LED street lamp module and preparation method thereof

Abstract

The application relates to an LED street lamp module and a preparation method thereof. The LED street lamp module comprises a PCB board, at least one flip LED chip, a light-emitting layer and a protective layer. The PCB board comprises a substrate layer, a heat-conducting insulating layer and a copper foil circuit layer arranged in a stack, and the copper foil circuit layer is provided with a flip chip pad circuit. The electrode of the flip LED chip is arranged towards the PCB board, the light-emitting surface of the flip LED chip faces away from the PCB board, the flip LED chip is directly electrically connected and mechanically fixed with the flip chip pad circuit through a solder bump. The light-emitting layer comprises a fluorescent conversion layer covering the light-emitting surface of the flip LED chip, and is used for converting the outgoing light of the flip LED chip into light of a predetermined spectrum. The protective layer covers the light-emitting layer and is used for sealing and optically protecting the light-emitting layer. The technical scheme of the application can save an independent lamp bead support and gold wire, shorten a thermal resistance path, eliminate the risk of gold wire failure, reduce the light-emitting interface, and reduce the packaging cost.

Description

Technical Field

[0001] This application relates to the technical field of LED lighting packaging, and more particularly to an LED street light module and its manufacturing method. Background Technology

[0002] Most existing LED street light modules use an independent packaged LED chip solution. The LED chip is first die-bonded and wire-bonded into a ceramic, EMC or PPA bracket, and then encapsulated with adhesive to form an independent LED chip; then the LED chip is mounted on the PCB board by SMT, and a secondary lens is added on top of the PCB board.

[0003] The solution has the following drawbacks: the heat from the chip must be conducted to the PCB through multiple interfaces such as the bracket and solder layer, resulting in a long thermal resistance path and low heat dissipation efficiency; the upright chip relies on gold wire bonding, which poses a risk of poor soldering or breakage of the gold wire; the light output needs to pass through the encapsulation glue, the bracket reflective surface and the secondary lens, resulting in many optical path interfaces and large light loss; and each LED needs to be independently packaged and split, which involves many processes and high costs.

[0004] Therefore, there is an urgent need for an LED street light module that can eliminate the need for separate LED chip brackets and gold wires, allowing flip-chip LEDs to be directly integrated onto the PCB, shortening the thermal resistance path, simplifying the light emission path, and reducing packaging costs. Summary of the Invention

[0005] This application provides an LED street light module and its manufacturing method, which can eliminate the need for independent LED bead brackets and gold wires, shorten the thermal resistance path, eliminate the risk of gold wire failure, reduce the light emission interface, and lower the packaging cost.

[0006] In a first aspect, this application provides an LED street light module, comprising: a PCB board, at least one flip-chip LED, a light-emitting layer, and a protective layer; the PCB board includes a substrate layer, a thermally conductive insulating layer, and a copper foil circuit layer stacked together, wherein the copper foil circuit layer is provided with flip-chip pad circuitry; the electrodes of the flip-chip LED are disposed facing the PCB board, the light-emitting surface of the flip-chip LED is facing away from the PCB board, and the flip-chip LED is directly electrically connected and mechanically fixed to the flip-chip pad circuitry via solder bumps; the light-emitting layer includes a phosphor conversion layer covering the light-emitting surface of the flip-chip LED for converting the emitted light of the flip-chip LED into light of a predetermined spectrum; the protective layer covers the light-emitting layer for sealing and optical protection of the light-emitting layer.

[0007] In one possible implementation, the substrate layer is a metal base layer with a thickness of 1.0 mm to 2.0 mm; the thermally conductive insulating layer has a thickness of 80 μm to 150 μm and a thermal conductivity of not less than 2.0 W / (m²). K); the thickness of the copper foil circuit layer is 35μm to 70μm.

[0008] In one possible implementation, the fluorescence conversion layer is a pre-formed phosphor film covering the light-emitting surface of the flip-chip LED; the pre-formed phosphor film includes a substrate layer and a phosphor adhesive layer stacked together, the thickness of the substrate layer being 30 μm to 80 μm; the thickness of the phosphor adhesive layer being 100 μm to 500 μm, and the weight ratio of phosphor to matrix silica in the phosphor adhesive layer being 1:7 to 1:5; the phosphor is selected from YAG:Ce yellow phosphor, or a combination of YAG:Ce yellow phosphor and nitride red phosphor, and the nitride red phosphor accounts for 5 wt% to 20 wt% of the total weight of the phosphor.

[0009] In one possible implementation, the protective layer is an integral silicone lens directly molded above the pre-formed fluorescent film and covering the area where the flip-chip LED is located; the integral silicone lens is made of transparent silicone with a refractive index of 1.41 to 1.53; the integral silicone lens is hemispherical, aspherical, or freeform.

[0010] In one possible implementation, the fluorescence conversion layer is a fluorescent adhesive layer, and the light-emitting layer further includes a dam structure; the dam structure is disposed on the surface of the PCB board around the flip-chip and forms a cavity, the fluorescent adhesive layer fills the cavity and covers the flip-chip; the protective layer is a transparent silicone cover layer covering the dam structure and the fluorescent adhesive layer.

[0011] In one possible implementation, the dam structure is a white reflective wall formed of white silicone, white epoxy resin, or ceramic material; the height of the dam structure is 0.3 mm to 2.0 mm, and the sidewalls of the dam structure are at an angle of 60° to 80° to the horizontal plane; the weight ratio of phosphor to silicone in the fluorescent adhesive layer is 1:3 to 1:6, and the thickness of the fluorescent adhesive layer is 0.5 mm to 1.5 mm.

[0012] Secondly, this application provides a method for manufacturing an LED street light module as described above, comprising: preparing a PCB board, the PCB board comprising a substrate layer, a thermally conductive insulating layer and a copper foil circuit layer stacked together, and etching a flip-chip pad circuit on the copper foil circuit layer; setting the electrodes of the flip-chip LED chip facing the PCB board, and directly die-bonding the flip-chip LED chip to the flip-chip pad circuit through solder bumps, so that the flip-chip LED chip and the flip-chip pad circuit form an electrical connection and mechanical fixation; attaching a pre-made phosphor film with its phosphor adhesive layer facing the light-emitting surface of the flip-chip LED chip to one side of the light-emitting surface of the die-bonded flip-chip LED chip to form a light-emitting layer; and forming an integral silicone lens on top of the light-emitting layer by molding to form a protective layer, thereby completing the encapsulation of the LED street light module.

[0013] In one possible implementation, the die bonding is performed using a reflow soldering process or a eutectic soldering process; when using the reflow soldering process, lead-free solder is selected, and the peak temperature of the reflow soldering is 230°C to 280°C; when using the eutectic soldering process, gold-tin solder is selected, and the soldering temperature of the eutectic soldering is 290°C to 320°C.

[0014] Thirdly, this application provides a method for manufacturing an LED street light module as described above, comprising: preparing a PCB board, the PCB board comprising a substrate layer, a thermally conductive insulating layer and a copper foil circuit layer stacked together, and etching a flip-chip pad circuit on the copper foil circuit layer; setting the electrodes of the flip-chip LED chip toward the PCB board, and directly die-bonding the flip-chip LED chip to the flip-chip pad circuit through solder bumps, so that the flip-chip LED chip and the flip-chip pad circuit form an electrical connection and mechanical fixation; forming a dam structure on the surface of the PCB board around the die-bonded flip-chip LED chip, the dam structure forming a cavity to accommodate the flip-chip LED chip; filling the cavity with fluorescent adhesive and curing it to form a fluorescent adhesive layer covering the flip-chip LED chip; covering the dam structure and the fluorescent adhesive layer with transparent silicone and curing it to form a protective layer, thereby completing the encapsulation of the LED street light module.

[0015] In one possible implementation, the dam structure is formed on the surface of the PCB board by dispensing or patching and then cured; fluorescent adhesive is filled into the cavity using a multi-point scanning dispensing method, with the filling height of the fluorescent adhesive being flush with the top of the dam structure, and then pre-cured and cured.

[0016] This application provides an LED street light module and its manufacturing method, which has the following advantages compared with the prior art: Because flip-chip LEDs are directly electrically connected and mechanically fixed to the flip-chip pad circuitry on the copper foil circuit layer of the PCB board via solder bumps, the independent brackets, gold wires, and solder mounting interfaces of traditional LED chips are eliminated. This allows the chip's heat to be directly conducted to the substrate layer via the solder bumps, copper foil circuit layer, and thermally conductive insulating layer, shortening the thermal resistance path, improving heat dissipation efficiency, and eliminating the risk of gold wire soldering defects and breakage. Simultaneously, the light-emitting layer is a phosphor conversion layer covering the chip's light-emitting surface, and the protective layer covers the light-emitting layer. The light emission path only passes through the phosphor conversion layer and the protective layer, eliminating multiple interfaces such as bracket reflective surfaces, encapsulation silicone, and secondary lenses found in traditional solutions. This reduces light reflection and absorption losses, improving luminous efficiency. Furthermore, this structure eliminates the need for independent LED chip packaging processes and materials such as brackets and gold wires, reducing packaging costs. The protective layer also provides sealing and optical protection for the light-emitting layer, improving module reliability. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0020] Figure 1 This is a structural schematic diagram of one embodiment of an LED street light module provided in this application; Figure 2a This is a top view of the flip-chip pad circuit provided in this application; Figure 2b This is a side view of the flip-chip pad circuit provided in this application. Figure 3 This is a structural schematic diagram of another embodiment of an LED street light module provided in this application; Figure 4 This is a flowchart illustrating one embodiment of the method for manufacturing an LED street light module provided in this application; Figure 5 This is a structural schematic diagram of another embodiment of an LED street light module provided in this application; Figure 6a This is a structural schematic diagram of the rectangular dam provided in this application; Figure 6b This is a structural schematic diagram of the circular dam provided in this application; Figure 6c This is a structural schematic diagram of the L-shaped cofferdam provided in this application; Figure 6d This is a structural schematic diagram of the strip dam provided in this application; Figure 7 This is a flowchart illustrating another embodiment of the method for manufacturing an LED street light module provided in this application.

[0021] Figure label: PCB board 1, substrate layer 11, thermally conductive insulating layer 12, copper foil circuit layer 13, flip chip pad circuit 131, flip LED chip 2, solder bump 21, light-emitting layer 3, substrate layer 311, phosphor adhesive layer 312, dam structure 32, phosphor adhesive layer 33, protective layer 4, integral silicone lens 41, transparent silicone cover layer 42. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0024] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0025] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0026] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0027] As used in this specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrases "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0028] Example 1, see Figure 1 , Figure 1 This is a structural schematic diagram of one embodiment of an LED street light module provided in this application, as shown below. Figure 1 As shown, the LED street light module has a flat module structure. The LED street light module includes a PCB board 1, at least one flip-chip LED 2, a light-emitting layer 3, and a protective layer 4, as detailed below: In one embodiment, the PCB board 1 includes a substrate layer 11, a thermally conductive insulating layer 12, and a copper foil circuit layer 13 stacked together, and the copper foil circuit layer 13 is provided with flip-chip pad circuit 131.

[0029] Specifically, PCB 1 uses a metal core printed circuit board (MCPCB).

[0030] Specifically, the substrate layer 11 is a metal base layer, specifically an aluminum plate or a copper plate, and the thickness of the metal base layer is 1.0 mm to 2.0 mm.

[0031] Specifically, a thermally conductive insulating layer 12 is stacked on the upper surface of the substrate layer 11 to achieve electrical insulation and heat conduction between the copper foil circuit layer 13 and the substrate layer 11. The thermally conductive insulating layer 12 is a thermally conductive silicone film or a ceramic filler layer, with a thickness of 80 μm to 150 μm, and a thermal conductivity of not less than 2.0 W / (m²). K).

[0032] Specifically, the copper foil circuit layer 13 is stacked on the upper surface of the thermally conductive insulating layer 12; the copper foil circuit layer 13 is copper foil, and the thickness of the copper foil circuit layer 13 is 35μm to 70μm; preferably, the thickness of the copper foil circuit layer 13 is 70μm.

[0033] Specifically, a flip-chip pad circuit 131 is formed on the copper foil circuit layer 13 by an etching process. The flip-chip pad circuit 131 includes multiple pads arranged in an array and series and parallel circuits connecting each pad. The position, spacing and arrangement of the pads of the flip-chip pad circuit 131 are customized according to the light source design requirements of the street light module.

[0034] Preferably, the flip-chip pad circuit 131 has 240 pads arranged in a 10×24 array, with a pad spacing of 2.0mm. The series-parallel circuit is a hybrid circuit of 10 series × 24 parallel, adapted for 30V / 2.4A constant current drive. The pad surface is treated with chemical nickel-gold surface treatment, with a gold layer thickness of 0.05μm to 0.10μm to enhance the wettability of the solder bumps 21. Alternatively, the pad surface can also be treated with an organic solder resist film. Figure 2a As shown, Figure 2a This is a top view of the flip-chip pad circuit 131 provided in this application; as shown Figure 2b As shown, Figure 2b This is a side view of the flip-chip pad circuit 131 provided in this application.

[0035] Specifically, the external dimensions of PCB board 1 are designed according to the specifications of the street light module; preferably, the external dimensions of PCB board 1 are 60mm×60mm, corresponding to a 72W module; as an optional solution, the external dimensions of PCB board 1 can also be 120mm×40mm, corresponding to a 144W module.

[0036] With this configuration, PCB board 1 serves as both a circuit board and a structural support. The copper foil circuit layer 13 provides electrical interconnection, while the substrate layer 11 provides physical support, eliminating the need for the traditional LED chip support structure. The heat generated by the flip-chip LED 2 can be directly conducted to the substrate layer 11 via the solder bumps 21, the copper foil circuit layer 13, and the thermally conductive insulating layer 12, and then conducted to the external heat sink via the substrate layer 11. The heat flow path is: chip - solder bumps 21 - copper foil circuit layer 13 - thermally conductive insulating layer 12 - substrate layer 11 - external heat sink. This eliminates the thermal resistance interfaces such as the packaging bracket and solder layer in the traditional solution. According to thermal resistance network simulation estimation, the total thermal resistance can be reduced from 8K / W to 15K / W in the traditional solution to 2K / W to 5K / W, a reduction of more than 60%, which is beneficial for reducing chip junction temperature, reducing light decay, and extending module life.

[0037] In one embodiment, the electrodes of the flip-chip LED 2 are positioned facing the PCB board 1, and the light-emitting surface of the flip-chip LED 2 faces away from the PCB board 1. The flip-chip LED 2 is directly electrically connected and mechanically fixed to the flip-chip pad circuit 131 through solder bumps 21.

[0038] Specifically, the flip-chip 2 is a GaN-based blue flip-chip with a peak wavelength of 450nm to 460nm; the chip size is 10mil×10mil to 60mil×60mil, approximately 0.25mm×0.25mm to 1.5mm×1.5mm.

[0039] Specifically, the P and N electrodes of the flip LED chip 2 are located on the bottom surface of the flip LED chip 2, facing the PCB board 1, and the light-emitting surface of the flip LED chip 2 faces away from the PCB board 1, that is, the P and N electrodes of the flip LED chip 2 are set downwards, and the light-emitting surface of the flip LED chip 2 is set upwards; the flip LED chip 2 is directly electrically connected and mechanically fixed to the flip chip pad circuit through solder bumps 21.

[0040] Specifically, SnAg3.0Cu0.5 lead-free solder bumps 21 are pre-placed on the pads, with a bump diameter of approximately 150μm. The flip-chip LED 2 is die-bonded onto the pads using a reflow soldering process. The peak reflow temperature is 260℃, and the peak holding time is 30 to 60 seconds. Nitrogen protection is applied throughout the soldering process, with an oxygen content of less than 1000ppm. As an optional solution, for scenarios with higher reliability requirements, a gold-tin eutectic soldering process can be used, employing AuSn20 gold-tin solder, with a soldering temperature of 290℃ to 320℃.

[0041] Specifically, multiple flip-chip LEDs 2 are arranged on the same PCB board 1 in series, parallel or a combination of series and parallel to form a surface light source.

[0042] Specifically, through the aforementioned die bonding method, the flip-chip LED 2 is directly soldered to the pads on the PCB board 1 via solder bumps 21, eliminating the need for gold wire bonding. This structurally eliminates the risk of failure due to poor soldering and breakage of gold wires. Based on the failure mechanism comparison analysis, the module failure rate is expected to be reduced by about 50% compared to the traditional solution. At the same time, the thermal resistance of the solder bumps 21 is much lower than that of gold wire bonding and the LED bead support structure, further shortening the heat flow path.

[0043] In one embodiment, the light-emitting layer 3 includes a phosphor conversion layer covering the light-emitting surface of the flip-chip LED chip 2, used to convert the emitted light of the flip-chip LED chip 2 into light of a predetermined spectrum.

[0044] Specifically, the fluorescence conversion layer is a pre-formed fluorescent film covering the light-emitting surface of the flip-chip LED 2, that is, covering the flip-chip LED 2; the pre-formed fluorescent film includes a substrate layer 311 and a phosphor adhesive layer 312 stacked together.

[0045] Specifically, the substrate layer 311 is a PET film with a thickness of 30 μm to 80 μm, used to support the phosphor adhesive layer 312 and provide film strength. Preferably, the substrate layer 311 has a thickness of 50 μm. Specifically, the phosphor adhesive layer 312 is stacked on the side of the substrate layer 311 near the flip-chip LED chip 2, and the thickness of the phosphor adhesive layer 312 is 100μm to 500μm; preferably, the thickness of the phosphor adhesive layer 312 is 200μm.

[0046] Specifically, the phosphor adhesive layer 312 is formed by mixing phosphor and matrix silica. The weight ratio of phosphor to matrix silica in the phosphor adhesive layer 312 is 1:7 to 1:5, which can be adjusted within the range of 12wt% to 17wt%, i.e., the weight ratio is approximately 1:7 to 1:5, depending on the target color temperature.

[0047] Specifically, the phosphor is selected from YAG:Ce yellow phosphor, or a combination of YAG:Ce yellow phosphor and nitride red phosphor, wherein the nitride red phosphor is selected from... (Peak emission 630nm to 650nm) or (Peak emission 620nm to 640nm), and the nitride red phosphor accounts for 5wt% to 20wt% of the total phosphor weight; preferably, YAG:Ce yellow phosphor is used.

[0048] Specifically, the pre-formed fluorescent film can be cut and bonded according to the target color temperature (3000K to 6500K). With its phosphor adhesive layer 312 facing the light-emitting surface of the flip-chip 2, it is bonded to the light-emitting side of the flip-chip 2 after die bonding to form the light-emitting layer 3. Before bonding, the flip-chip 2 is first cleaned with oxygen plasma (power 100W, time 60 seconds) to activate the chip surface. The bonding is carried out using a vacuum bonding machine with a bonding temperature of 80℃ and a pressure of 0.3MPa. After bonding, it is cured at 70℃ for 2 hours.

[0049] Specifically, since the pre-fabricated phosphor film has a sheet-like structure, its thickness deviation is less than ±5%, while that of the traditional dispensing process is about ±15%. Its thickness uniformity is better than that of the phosphor adhesive layer 33 formed by the traditional dispensing process. Moreover, the phosphor distribution is more uniform, which is conducive to improving the color temperature uniformity. The color temperature uniformity can be improved from 5 to 7 levels in the traditional solution to 2 to 3 levels. At the same time, the phosphor adhesive layer 312 faces the chip light-emitting surface, which shortens the distance between the phosphor and the chip. This is conducive to reducing the propagation loss of light in the phosphor adhesive layer 312 and improving the light extraction efficiency.

[0050] In one embodiment, the protective layer 4 covers the light-emitting layer 3, serving to seal and optically protect the light-emitting layer 3.

[0051] Specifically, the protective layer 4 is an integral silicone lens 41 directly molded on top of the pre-formed fluorescent film, covering the area where the flip-chip 2 is located. The integral silicone lens 41 is made of high-refractive-index transparent silicone with a refractive index of 1.41 to 1.53 and a light transmittance greater than 92%; preferably, the refractive index of the transparent silicone is 1.51.

[0052] Specifically, the integral silicone lens 41 is hemispherical, aspherical, or freeform; preferably, the integral silicone lens 41 is freeform.

[0053] Specifically, the integral silicone lens 41 covers the area where the flip-chip 2 is located (approximately 48mm × 20mm), and the lens height is 3.0mm, which can be selected within the range of 3mm to 6mm. During molding, an integral lens mold is placed on top of the pre-formed fluorescent film, transparent silicone is injected, and it is cured at 150°C for 1 hour. After demolding, the integral silicone lens 41 is directly formed on top of the pre-formed fluorescent film.

[0054] Preferably, the light-emitting surface of the integral silicone lens 41 is optically designed to achieve module-level light distribution, such as bat wing light distribution; and the integral silicone lens 41 is directly formed on top of the pre-made fluorescent film, eliminating the secondary lens installation step in the traditional solution, and realizing the integration of optical protection and light shaping.

[0055] like Figure 3 As shown, Figure 3 This is a structural schematic diagram of another embodiment of an LED street light module provided in this application.

[0056] Specifically, based on the above settings, the light output path of the LED street light module provided in this application is flip-chip LED 2 - pre-formed fluorescent film - integral silicone lens 41 - air. There is only one silicone-air interface, which eliminates the bracket reflector and secondary lens in the traditional solution. The light path interface is smaller, the light reflection and absorption loss is smaller, and the system luminous efficiency is higher. The integral silicone lens 41 covers the entire chip array area while forming a seal and optical protection for the light-emitting layer 3 and realizing module-level light distribution. There is no need to install a secondary lens, the assembly process is smaller, and the module structure is more compact.

[0057] In this embodiment, the luminous efficacy of the LED street light module can reach approximately 210 lm / W, which is about 23.5% higher than the approximately 170 lm / W of the traditional solution. The overall luminous efficacy can cover the range of 200 lm / W to 230 lm / W. At the same time, since the packaging process of individual LED chips, as well as materials such as brackets, gold wires and individual encapsulating colloids are eliminated, the packaging process can be reduced from 12 steps in the traditional solution to 5 to 6 steps, and the BOM cost can be reduced by 20% to 35%. The lifespan is expected to be increased by 30% to 60%.

[0058] This embodiment also provides a method for manufacturing an LED street light module, see [link]. Figure 4 , Figure 4 This is a flowchart illustrating an embodiment of a method for manufacturing an LED street light module provided in this application. The method includes the following steps: Step 101: Prepare PCB board 1, which includes a substrate layer 11, a thermally conductive insulating layer 12 and a copper foil circuit layer 13 stacked together, and etch flip chip pad circuit 131 on the copper foil circuit layer 13.

[0059] In one embodiment, the PCB board 1 is an aluminum-based MCPCB with a thermal conductivity of 2.5 W / (m·K).

[0060] In one embodiment, the PCB board 1 comprises, from bottom to top: a substrate layer 11, which is a metal base layer, specifically an aluminum plate with a thickness of 1.5 mm; a thermally conductive insulating layer 12, which is a thermally conductive silicone film with a thickness of 100 μm and a thermal conductivity of 2.5 W / (m·K); and a copper foil circuit layer 13, which is a copper foil with a thickness of 70 μm.

[0061] In one embodiment, a flip-chip pad circuit 131 is formed on the copper foil circuit layer 13 by an etching process. The flip-chip pad circuit 131 is configured to carry 240 flip-chip LED chips 2 arranged in a 10×24 array. The size of each flip-chip LED chip 2 is 40mil×40mil (approximately 1.0mm×1.0mm). The pad spacing of the flip-chip pad circuit 131 is 2.0mm. The copper foil circuit layer 13 is also etched with a series-parallel hybrid circuit, which consists of 10 series × 24 parallel circuits, adapted to 30V / 2.4A constant current drive; the driving current of a single flip-chip LED 2 is about 100mA, which is derating relative to the rated current of 350mA to control junction temperature and light decay; the forward voltage of a single flip-chip LED 2 is about 2.7V to 2.8V, and the total voltage of 10 series is about 27V to 28V, adapted to 30V constant current drive output; the module power is 30V × 2.4A = 72W.

[0062] In one embodiment, the surface of the pads of the flip-chip pad circuit 131 is treated with chemical nickel-gold plating, and the gold layer thickness is 0.05μm to 0.10μm. The PCB board 1 has external dimensions of 60mm × 60mm.

[0063] Step 102: Position the electrodes of the flip-chip LED 2 toward the PCB board 1, and directly die bond the flip-chip LED 2 to the flip-chip pad circuit 131 through the solder bumps 21, so that the flip-chip LED 2 and the flip-chip pad circuit 131 form an electrical connection and mechanical fixation.

[0064] In one embodiment, the flip-chip 2 is a GaN-based blue flip-chip LED with a peak wavelength of 455nm and a forward voltage of 2.8V to 3.2V at 350mA.

[0065] In one embodiment, the P electrode and N electrode of the flip-chip 2 are located on the bottom surface of the chip, so that the electrodes of the flip-chip 2 are oriented toward the PCB board 1.

[0066] In one embodiment, SnAg3.0Cu0.5 lead-free solder bumps 21 are pre-placed on the flip chip pad circuit 131. The solder bumps 21 have a melting point of 217°C and a bump diameter of approximately 150 μm.

[0067] In one embodiment, the die bonding is performed using a reflow soldering process or a eutectic soldering process; when using the reflow soldering process, lead-free solder is selected, and the peak temperature of the reflow soldering is 230°C to 280°C; when using the eutectic soldering process, gold-tin solder is selected, and the eutectic soldering temperature is 290°C to 320°C; nitrogen protection is applied during the soldering process, and the oxygen content is less than 1000ppm.

[0068] Specifically, a high-precision die bonder (accuracy ±10μm) is used to pick up, align, and place the flip-chip LED chip 2 onto the flip-chip pad circuit 131. Reflow soldering is employed for die bonding, with a peak temperature of 260℃ and a peak holding time of 30 to 60 seconds, under nitrogen protection throughout the process, with an oxygen content of less than 1000ppm. After reflow soldering, the solder bumps 21 directly electrically connect and mechanically fix the flip-chip LED chip 2 to the flip-chip pad circuit 131. Since gold wire bonding is not required, the risk of gold wire bonding defects and breakage is structurally eliminated.

[0069] Specifically, for scenarios with higher reliability requirements, gold-tin eutectic bonding can be used for die bonding, with AuSn20 solder selected and a bonding temperature of 290℃ to 320℃.

[0070] Step 103: The pre-made fluorescent film is attached to the light-emitting side of the flip-chip 2 after die bonding, with its phosphor adhesive layer 312 facing the light-emitting surface of the flip-chip 2, to form the light-emitting layer 3.

[0071] In one embodiment, the pre-fabricated fluorescent film includes a substrate layer 311 and a phosphor adhesive layer 312 stacked together. The substrate layer 311 is a PET film with a thickness of 50 μm. The phosphor adhesive layer 312 is a silicone matrix containing YAG:Ce yellow phosphor at a concentration of approximately 15 wt%, i.e., the weight ratio of phosphor to silicone matrix is ​​approximately 1:5.7. Depending on the target color temperature, the phosphor concentration can be adjusted within the range of 12 wt% to 18 wt%, i.e., the weight ratio of phosphor to silicone matrix is ​​approximately 1:7 to 1:5. The phosphor adhesive layer 312 has a thickness of 200 μm, and the target color temperature is designed to be 5000K ± 200K.

[0072] In one embodiment, after die bonding and before attaching the pre-formed phosphor film, the flip-chip 2 is subjected to plasma cleaning using O2 plasma at a power of 100W for 60 seconds to activate the surface of the flip-chip 2.

[0073] In one embodiment, the pre-formed fluorescent film is cut to a size that covers the entire flip-chip array area. The pre-formed fluorescent film is then bonded to the light-emitting side of the flip-chip 2 after die bonding using a vacuum bonding machine, with its phosphor adhesive layer 312 facing the light-emitting surface of the flip-chip 2. The bonding temperature is 80°C and the pressure is 0.3 MPa. After bonding, the film is cured at 70°C for 2 hours to form the light-emitting layer 3.

[0074] Step 104: An integral silicone lens 41 is formed on top of the light-emitting layer 3 using a mold to form a protective layer 4, thus completing the encapsulation of the LED street light module.

[0075] In one embodiment, an integral lens mold is placed above the light-emitting layer 3. The integral lens mold is made of stainless steel and coated with a Teflon anti-stick layer; the integral lens mold is configured to form an integral structure covering the entire array area containing the flip-chip 2, the array area of ​​which is approximately 48mm × 20mm. The height of the integral silicone lens 41 is 3.0mm, preferably 3mm to 6mm. The light-emitting surface of the integral silicone lens 41 is designed as a freeform surface, for example, optimized using optical simulation software, to achieve batwing-like light distribution.

[0076] In one embodiment, transparent silicone is injected into the integral lens mold. The transparent silicone has a refractive index of 1.51 and a light transmittance greater than 92%. After curing at 150°C for 1 hour and demolding, the transparent silicone is directly formed on top of the pre-formed fluorescent film, forming an integral silicone lens 41, i.e., the protective layer 4. The integral silicone lens 41 covers the area where the flip-chip 2 is located, replacing the traditional secondary lens and achieving integrated optical protection and light shaping.

[0077] With this configuration, the integral silicone lens 41 is directly formed on top of the pre-formed fluorescent film, eliminating the need for a secondary lens installation step. At the same time, it achieves sealing and optical protection for the light-emitting layer 3 and can shape the emitted light, which is beneficial to improving light efficiency.

[0078] In the above preparation method, the flip chip pad circuit 131 formed in step 101 provides a welding position for the die bonding of the flip LED chip 2 in step 102; the flip LED chip 2 after die bonding in step 102 provides a bearing surface for the bonding of the pre-formed phosphor film in step 103; the light-emitting layer 3 formed in step 103 provides a molding base surface for the molding of the integral silicone lens 41 in step 104. Each step is sequentially connected, and the process is continuous. There is no need for independent LED chip packaging and secondary lens installation processes, which helps to shorten the production process and reduce packaging costs.

[0079] Example 2, see Figure 5 , Figure 5 This is a schematic diagram of another embodiment of an LED street light module provided in this application. In this embodiment, the LED street light module includes a PCB board 1, at least one flip-chip LED 2, a light-emitting layer 3, and a protective layer 4. The light-emitting layer 3 includes a phosphor conversion layer covering the light-emitting surface of the flip-chip LED 2. The difference between this embodiment and embodiment 1 is that the structure and formation method of the light-emitting layer 3 and the protective layer 4 are different. The structure of the PCB board 1 and the die bonding method of the flip-chip LED 2 are the same as those in embodiment 1, and will not be described again here.

[0080] In one embodiment, the fluorescence conversion layer is a fluorescent adhesive layer 33, and the light-emitting layer 3 further includes a dam structure 32; the dam structure 32 is disposed around the flip-chip LED 2 on the surface of the PCB board 1 and forms a cavity, the fluorescent adhesive layer 33 fills the cavity and covers the flip-chip LED 2; the protective layer 4 is a transparent silicone cover layer 42 covering the dam structure 32 and the fluorescent adhesive layer 33.

[0081] Specifically, the dam structure 32 is a white reflective wall, which is formed of white silicone, white epoxy resin or ceramic material.

[0082] Preferably, the dam structure 32 is composed of added The filler is formed by white high-reflectivity silicone with a reflectivity greater than 95%, and is formed on the surface of PCB board 1 by dispensing and printing and then cured; as an optional solution, the dam structure 32 can also be formed by patching; the sidewall of the dam structure 32 is at an angle of 60° to 80° to the horizontal plane.

[0083] Preferably, the shape of the dam structure 32 is a rectangle with a length of 60mm, a width of 20mm, and a height of 1.0mm.

[0084] Specifically, the height of the dam structure 32 is 0.3mm to 2.0mm: a 0.3mm thin dam corresponds to a shallow adhesive layer (about 0.5mm), which has a higher light efficiency orientation; a 2.0mm high dam corresponds to a deep cavity (adhesive layer about 1.5mm), which has a higher light emission uniformity orientation.

[0085] Specifically, the shape of the dam structure 32 can be customized according to the shape of the target light-emitting surface, including rectangular, circular, polygonal, or irregular shapes. For example: a rectangular dam corresponds to a rectangular light spot, suitable for lighting on both sides of a main road; a circular dam corresponds to a circular light spot, suitable for high-mast lighting; an L-shaped dam corresponds to an L-shaped light spot, suitable for corners at intersections; a strip-shaped dam corresponds to a strip-shaped light spot, suitable for tunnel lighting; and so on. Figure 6a As shown, Figure 6a This is a structural schematic diagram of the rectangular dam provided in this application; as shown Figure 6b As shown, Figure 6b This is a schematic diagram of the circular dam provided in this application; as shown. Figure 6c As shown, Figure 6c This is a structural schematic diagram of the L-shaped cofferdam provided in this application; as shown Figure 6d As shown, Figure 6d This is a structural schematic diagram of the strip dam provided in this application.

[0086] Specifically, the dam structure 32 forms a cavity on the surface of the PCB board 1 to accommodate the flip-chip LED 2, providing a space and boundary constraints for the filling of the phosphor layer 33. The shape and area of ​​the phosphor layer 33 are defined by the dam structure 32. The shape and height of the dam structure 32 can be customized according to the light distribution requirements of the street light, thereby customizing the shape and area of ​​the light-emitting surface. It can adapt to various road lighting scenarios without replacing the secondary lens. Moreover, the dam structure 32 is a white high-reflectivity wall. The inner wall can reflect the light incident on its side back to the light-emitting direction, reducing side light loss and improving light emission efficiency.

[0087] Specifically, the fluorescent adhesive layer 33 fills the cavity enclosed by the dam structure 32 and covers the flip-chip LED chip 2.

[0088] Specifically, the fluorescent adhesive layer 33 is prepared by mixing transparent silicone and phosphor. For example, the fluorescent adhesive layer 33 is prepared by mixing YAG:Ce yellow phosphor (D50 particle size 15μm) and transparent silicone at a weight ratio of 1:4 (approximately 20wt%). After vacuum degassing for 10 minutes, the fluorescent adhesive is filled into the cavity using a multi-point scanning dispensing method. The filling height is flush with the top of the dam structure 32 (approximately 1.0mm). It is pre-cured at 80℃ for 30 minutes and then cured at 150℃ for 2 hours. The weight ratio of phosphor to silicone in the fluorescent adhesive layer 33 is 1:3 to 1:6. Among them, approximately 1:3 (approximately 25wt%) corresponds to 3000K warm white light output, and approximately 1:6 (approximately 14wt%) corresponds to 6500K cool white light output, thereby achieving an adjustable light output color temperature within the range of 3000K to 6500K. The thickness of the fluorescent adhesive layer 33 is 0.5mm to 1.5mm. Since the fluorescent adhesive layer 33 is not supported by the substrate layer 311, the phosphor concentration needs to be increased to compensate for the effect of the adhesive layer thickness change on the excitation amount. Therefore, in this embodiment, the phosphor concentration of the fluorescent adhesive is higher than the phosphor concentration of the pre-made fluorescent film in Example 1.

[0089] Specifically, by adjusting the phosphor concentration, the thickness of the phosphor adhesive layer 33, and the shape of the dam structure 32, the emitted color temperature, light spot shape, and emitting area can be flexibly customized. The phosphor adhesive layer 33 is confined and shaped within the cavity enclosed by the dam structure 32, with smooth edges and clear boundaries of the emitting surface, which helps improve the consistency and uniformity of the emitting surface. By changing the shape and size of the dam structure 32, more than five light distribution schemes can be achieved on the same PCB platform without replacing the secondary lens or redesigning the PCB board 1.

[0090] Specifically, the protective layer 4 is a transparent silicone covering layer 42 that covers the dam structure 32 and the fluorescent adhesive layer 33.

[0091] Specifically, transparent silicone is applied and covered above the dam structure 32 and the fluorescent adhesive layer 33. The silicone has a refractive index of 1.51 and a thickness of 0.5 mm to 1.0 mm. It is then cured at 150°C for 1 hour to form a transparent silicone covering layer 42.

[0092] Specifically, the transparent silicone cover layer 42 covers the dam structure 32 and the fluorescent adhesive layer 33, forming a seal and optical protection for the fluorescent adhesive layer 33, preventing the fluorescent adhesive layer 33 from getting damp, oxidized and mechanically damaged, which is beneficial to improving the environmental reliability and service life of the module; at the same time, the transparent silicone cover layer 42 is transparent and light-transmitting, and does not affect the customized effect of the dam structure 32 on the light-emitting surface.

[0093] This embodiment and Embodiment 1 constitute two light-emitting schemes on the same PCB platform: the two schemes share the same PCB board 1 and flip-chip LED chip 2 die bonding process, only the formation processes of the light-emitting layer 3 and the protective layer 4 are different.

[0094] Example 1 is suitable for main road lighting scenarios with the highest requirements for light efficiency, and the module light efficiency can cover the range of 200lm / W to 230lm / W; while this example is suitable for special road lighting scenarios that require customized light distribution, and the shape of the light-emitting surface can be freely customized; the two solutions can be flexibly switched on the same PCB platform according to the application scenario requirements, the platform has a high reusability rate, and the product development cycle can be shortened by about 40%.

[0095] Regarding the LED street light module provided in this embodiment, this embodiment also provides a method for manufacturing the LED street light module. Compared with the manufacturing method provided in Embodiment 1, steps 201 and 202 in this embodiment are the same as steps 101 and 102 mentioned in Embodiment 1. The difference lies in the fact that steps 203-205 in this embodiment differ from steps 103-104 mentioned in Embodiment 1; see also Figure 7 , Figure 7 This is a flowchart illustrating another embodiment of the method for manufacturing an LED street light module provided in this application. The method includes the following steps: Step 201: Prepare PCB board 1, which includes a substrate layer 11, a thermally conductive insulating layer 12 and a copper foil circuit layer 13 stacked together, and etch flip chip pad circuit 131 on the copper foil circuit layer 13.

[0096] Step 202: Position the electrodes of the flip-chip LED 2 toward the PCB board 1, and directly die bond the flip-chip LED 2 to the flip-chip pad circuit 131 through the solder bumps 21, so that the flip-chip LED 2 and the flip-chip pad circuit 131 form an electrical connection and mechanical fixation.

[0097] Step 203: A dam structure 32 is formed on the surface of the PCB board 1 around the flip-chip 2 after die bonding. The dam structure 32 forms a cavity to accommodate the flip-chip 2.

[0098] In one embodiment, the dam structure 32 is formed on the surface of the PCB board 1 by dispensing or patching and then cured.

[0099] Specifically, using a dispensing machine (accuracy ±0.05mm), a dam structure 32 is printed on the surface 1 of the PCB board around the flip-chip 2 after die bonding. The dam structure 32 forms a cavity to accommodate the flip-chip 2. The dam structure 32 is formed of white high-reflectivity silicone, which contains TiO2 filler and has a reflectivity greater than 95%.

[0100] In one embodiment, the dam structure 32 is rectangular in shape, with a length of 60mm, a width of 20mm, and a height of 1.0mm, corresponding to a rectangular light spot of 60mm×20mm, which is suitable for lighting on both sides of the main road.

[0101] In one embodiment, the sidewall of the dam structure 32 forms a 75° angle with the horizontal plane.

[0102] In one embodiment, the dam structure 32 is printed and then cured at 150°C for 30 minutes to form a white reflective wall cavity. The high reflectivity of the white inner wall of the dam structure 32 reduces lateral light loss.

[0103] In one embodiment, the height of the dam structure 32 can be selected from 0.3mm to 2.0mm: a 0.3mm thin dam corresponds to a shallow adhesive layer of about 0.5mm, resulting in higher luminous efficiency; a 2.0mm high dam corresponds to a deep cavity adhesive layer of about 1.5mm, resulting in higher luminous uniformity.

[0104] Step 204: Fill the cavity with fluorescent adhesive and cure it to form a fluorescent adhesive layer 33 covering the flip-chip LED 2.

[0105] In one embodiment, fluorescent adhesive is filled into the cavity using a multi-point scanning dispensing method. The filling height of the fluorescent adhesive is flush with the top of the dam structure 32. After filling, pre-curing and curing are performed.

[0106] Specifically, to prepare the fluorescent gel, YAG:Ce yellow fluorescent powder (D50 particle size of 15μm) is mixed with transparent silica gel at a weight ratio of 1:4, that is, the fluorescent powder concentration is about 20wt%, and vacuum degassing is performed for 10 minutes.

[0107] Specifically, the fluorescent adhesive is filled into the cavity enclosed by the dam structure 32 using a multi-point scanning dispensing method. The filling height is flush with the top of the dam structure 32, approximately 1.0 mm. After filling, it is pre-cured at 80°C for 30 minutes, and then cured at 150°C for 2 hours to form a fluorescent adhesive layer 33 covering the flip-chip LED 2.

[0108] In one embodiment, the emitted color temperature, light spot shape, and luminous area are precisely controlled by adjusting the concentration of phosphor in the fluorescent adhesive, the thickness of the fluorescent adhesive layer 33, and the shape of the dam structure 32. The weight ratio of phosphor to silica gel can be adjusted within the range of 1:3 to 1:6: approximately 1:3 (approximately 25 wt%) corresponds to 3000K warm white light output, and approximately 1:6 (approximately 14 wt%) corresponds to 6500K cool white light output.

[0109] In one embodiment, the phosphor concentration in the fluorescent adhesive is higher than that in the pre-fabricated fluorescent film in Example 1 (approximately 15 wt%). This is because the fluorescent adhesive layer 33 is not supported by the substrate layer 311, and the phosphor concentration needs to be increased to compensate for the effect of thickness variation on the excitation amount.

[0110] Step 205: Cover the dam structure 32 and the fluorescent adhesive layer 33 with transparent silicone and cure it to form a protective layer 4, thus completing the encapsulation of the LED street light module.

[0111] In one embodiment, a transparent silicone coating with a refractive index of 1.51 and a coating thickness of 0.5 mm to 1.0 mm is applied over the dam structure 32 and the fluorescent adhesive layer 33 by dispensing. The coating is cured at 150°C for 1 hour to form a transparent silicone coating layer 42, i.e., the protective layer 4, thus completing the encapsulation of the LED street light module.

[0112] In one embodiment, the transparent silicone cover layer 42 is used to seal and optically protect the fluorescent adhesive layer 33.

[0113] In the above preparation method, the flip-chip 2 after die bonding in step 202 provides a positioning reference for the setting of the dam structure 32 in step 203. The cavity enclosed by the dam structure 32 provides a space for the filling of the fluorescent adhesive in step 204. The dam structure 32 and the fluorescent adhesive layer 33 formed in steps 203 and 204 provide a bearing surface for the covering of the transparent silicone cover layer 42 in step 205. Each step is connected in sequence, and the light-emitting surface can be flexibly customized on the same PCB platform, which is suitable for various road lighting scenarios.

[0114] Example 3: Based on Example 1 or Example 2, this example further integrates the LED driving circuit onto PCB board 1, which is suitable for scenarios with higher requirements for module integration.

[0115] In one embodiment, in addition to the flip chip pad area, the copper foil circuit layer 13 of the PCB board 1 also has a reserved area for the layout of driving circuits; the driving circuits are soldered in the driving circuit layout area using SMT process.

[0116] Specifically, the driving circuit includes a constant current driving IC, a sampling resistor, an inductor, and a capacitor.

[0117] Specifically, the output of the driving circuit is connected to the flip-chip pad circuit 131. The LED street light module receives an AC input through the driving circuit, with the AC input voltage ranging from 100V to 277V. The driving circuit is configured to convert the received AC input into a DC output and provide constant current drive to the flip-chip LED chip 2.

[0118] With this configuration, the driving circuit and the flip-chip LED 2 share the same PCB board 1. The module does not require an external independent driving board and connecting wires, which reduces connectors and soldering points, shrinks the module size, and lowers the system-level failure rate. This is conducive to the standardization, modularization, and mass production of street light modules.

[0119] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0120] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Since these modifications and variations fall within the scope of the claims and their equivalents, this application also intends to include these modifications and variations.

[0121] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An LED street light module, characterized in that, include: PCB board, at least one flip-chip LED, light-emitting layer, and protective layer; The PCB board includes a substrate layer, a thermally conductive insulating layer and a copper foil circuit layer stacked together, and the copper foil circuit layer is provided with flip-chip pad circuitry. The electrodes of the flip-chip LED are positioned facing the PCB board, while the light-emitting surface of the flip-chip LED is facing away from the PCB board. The flip-chip LED is directly electrically connected and mechanically fixed to the flip-chip pad circuit through solder bumps. The light-emitting layer includes a phosphor conversion layer covering the light-emitting surface of the flip-chip LED, used to convert the emitted light of the flip-chip LED into light of a predetermined spectrum; The protective layer covers the light-emitting layer and serves to seal and optically protect the light-emitting layer.

2. The LED street light module according to claim 1, characterized in that, The substrate layer is a metal base layer, and the thickness of the metal base layer is 1.0 mm to 2.0 mm; The thickness of the thermally conductive insulating layer is 80 μm to 150 μm, and the thermal conductivity of the thermally conductive insulating layer is not less than 2.0 W / (m²). K); The thickness of the copper foil circuit layer is 35 μm to 70 μm.

3. The LED street light module according to claim 1, characterized in that, The fluorescence conversion layer is a pre-formed fluorescent film covering the light-emitting surface of the flip-chip LED; The pre-formed fluorescent film includes a substrate layer and a phosphor adhesive layer stacked together, wherein the thickness of the substrate layer is 30 μm to 80 μm; The thickness of the phosphor adhesive layer is 100μm to 500μm, and the weight ratio of phosphor to matrix silica in the phosphor adhesive layer is 1:7 to 1:

5. The phosphor is selected from YAG:Ce yellow phosphor, or a combination of YAG:Ce yellow phosphor and nitride red phosphor, wherein the nitride red phosphor accounts for 5 wt% to 20 wt% of the total weight of the phosphor.

4. The LED street light module according to claim 3, characterized in that, The protective layer is an integral silicone lens that is directly molded onto the pre-formed fluorescent film and covers the area where the flip-chip LED is located. The integral silicone lens is made of transparent silicone with a refractive index of 1.41 to 1.

53. The integral silicone lens can be hemispherical, aspherical, or freeform.

5. The LED street light module according to claim 1, characterized in that, The fluorescence conversion layer is a fluorescent adhesive layer, and the light-emitting layer also includes a damming structure; The dam structure is disposed around the flip-chip LED on the surface of the PCB board and forms a cavity, and the fluorescent adhesive layer fills the cavity and covers the flip-chip LED; The protective layer is a transparent silicone coating layer that covers the dam structure and the fluorescent adhesive layer.

6. The LED street light module according to claim 5, characterized in that, The dam structure is a white reflective wall, which is formed of white silicone, white epoxy resin or ceramic material; The height of the dam structure is 0.3mm to 2.0mm, and the sidewalls of the dam structure form an angle of 60° to 80° with the horizontal plane; The phosphor to silica gel weight ratio in the fluorescent adhesive layer is 1:3 to 1:6, and the thickness of the fluorescent adhesive layer is 0.5 mm to 1.5 mm.

7. A method for manufacturing an LED street light module as described in claim 3 or 4, characterized in that, include: A PCB board is prepared, the PCB board comprising a substrate layer, a thermally conductive insulating layer and a copper foil circuit layer stacked together, and a flip-chip pad circuit is etched on the copper foil circuit layer; The electrodes of the flip-chip are positioned facing the PCB board, and the flip-chip is directly die-bonded to the flip-chip pad circuit through solder bumps, so that the flip-chip and the flip-chip pad circuit form an electrical connection and mechanical fixation. The pre-made fluorescent film is attached to the light-emitting side of the flip-chip after die bonding, with its phosphor adhesive layer facing the light-emitting surface of the flip-chip, to form a light-emitting layer; An integral silicone lens is molded on top of the light-emitting layer to form a protective layer, thus completing the encapsulation of the LED street light module.

8. The preparation method according to claim 7, characterized in that, The die bonding process is either reflow soldering or eutectic soldering. When using the reflow soldering process, lead-free solder is selected, and the peak temperature of the reflow soldering is 230°C to 280°C. When using the eutectic bonding process, gold-tin solder is selected, and the bonding temperature for eutectic bonding is 290°C to 320°C.

9. A method for manufacturing an LED street light module as described in claim 5 or 6, characterized in that, include: A PCB board is prepared, the PCB board comprising a substrate layer, a thermally conductive insulating layer and a copper foil circuit layer stacked together, and a flip-chip pad circuit is etched on the copper foil circuit layer; The electrodes of the flip-chip are positioned facing the PCB board, and the flip-chip is directly die-bonded to the flip-chip pad circuit through solder bumps, so that the flip-chip and the flip-chip pad circuit form an electrical connection and mechanical fixation. A dam structure is formed on the surface of the PCB board around the flip-chip after die bonding, and the dam structure forms a cavity to accommodate the flip-chip. The cavity is filled with fluorescent adhesive and cured to form a fluorescent adhesive layer covering the flip-chip LED. A transparent silicone sealant is applied over the dam structure and the fluorescent adhesive layer and cured to form a protective layer, thus completing the encapsulation of the LED street light module.

10. The preparation method according to claim 9, characterized in that, The dam structure is formed on the surface of the PCB board by dispensing or patching and then cured. Fluorescent adhesive is filled into the cavity using a multi-point scanning dispensing method. The filling height of the fluorescent adhesive is flush with the top of the dam structure. After filling, pre-curing and curing are performed.

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