LED packaging method based on fluorescent diaphragm and LED device

Abstract

The invention discloses an LED packaging method based on a fluorescent diaphragm and an LED device, and relates to the technical field of semiconductors, the packaging method comprises the following steps: providing an LED chip semi-finished product which has been subjected to die bonding and wire bonding, and installing an LED chip in a bowl cup of a packaging support; the preparation method comprises the following steps: mixing fluoride fluorescent powder, nitride red fluorescent powder and transparent silica gel, preparing a preformed fluorescent membrane by a membrane scraping process, and carrying out semi-curing treatment on the fluorescent membrane; the fluorescent film which is cut in advance is attached to the light emitting face of the LED chip; spot-covering at least one second fluorescent glue layer containing YAG fluorescent powder on the LED chip to which the fluorescent diaphragm is attached; and carrying out one-time baking curing on the LED chip subjected to glue dispensing, so that the fluorescent diaphragm and the second fluorescent glue layer are completely cured at the same time. By adopting the fluorescent diaphragm, the problem of settling of fluorescent powder is solved, the packaging process is simplified, and the optical performance is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and more specifically to an LED packaging method and LED device based on a fluorescent film. Background Technology

[0002] White LEDs, due to their energy-saving, environmentally friendly, and long lifespan advantages, have been widely used in lighting and display fields. To achieve high-quality white light with a high color rendering index (CRI), a common approach is to use blue LED chips to excite phosphors of multiple colors. Among these, fluoride phosphors (such as K2SiF6:Mn) are often used. 4+ Because it can emit red light with a narrow half-wavelength, it can effectively improve the color rendering index and color saturation of LED devices, and has become one of the key materials for high-end LED packaging.

[0003] Currently, the mainstream packaging process for high color rendering index and low color temperature LEDs is to use a double-layer dispensing technology: first, a first phosphor layer containing fluoride red phosphor is applied to the LED chip, and after centrifugation and baking curing, a second phosphor layer containing nitride red phosphor and yellow-green phosphor such as YAG is applied, and after centrifugation and baking again, the packaging is completed.

[0004] However, this existing technology has the following significant drawbacks: 1. Complex process and high cost: It requires two dispensing, two centrifugation and two baking processes, resulting in a long production cycle and high equipment occupancy, which leads to a significant increase in labor and manufacturing costs.

[0005] 2. Poor spectral consistency and low yield: Fluoride phosphors have a high density, and during dispensing and curing, they are prone to uneven distribution due to sedimentation and turbulence. This non-uniformity directly causes the color coordinates (X,Y) of LED devices in the same batch to be dispersed, i.e., "spectral dispersion," making it difficult to improve product yield.

[0006] 3. Low material utilization: In order to ensure the coverage effect of the lower red powder and the final color coordinates meet the standards, an excessive amount of fluoride phosphor is often required. However, this material is expensive, which increases the material cost.

[0007] 4. Loss of light efficiency: An uneven phosphor layer can lead to an imbalance in light absorption and conversion efficiency in local areas, resulting in self-absorption and thus reducing the light extraction efficiency of the LED.

[0008] 5. If all the phosphors are covered on the chip surface with a fluorescent film, it will also cause an imbalance in light absorption and conversion efficiency in local areas, resulting in phosphor reabsorption and thus reducing the light extraction efficiency of the LED.

[0009] Therefore, existing technologies face insurmountable bottlenecks in terms of production efficiency, product consistency, cost control, and optical performance, necessitating an innovative packaging method to systematically address these issues. Summary of the Invention

[0010] In view of the shortcomings of the prior art, the purpose of this invention is to provide an LED packaging method and LED device based on a fluorescent film, which aims to solve the above-mentioned problems described in the prior art.

[0011] A first aspect of the present invention is to provide an LED packaging method based on a fluorescent film, the packaging method comprising: Provide LED chip semi-finished products with completed die bonding and wire bonding, wherein the LED chip is installed in the cup of the packaging bracket; Fluoride phosphor, nitride red phosphor and transparent silicone are mixed and preformed into a fluorescent film by a coating process, and the fluorescent film is then semi-cured. The pre-cut fluorescent film is attached to the light-emitting surface of the LED chip; At least one layer of second fluorescent adhesive containing YAG phosphor is deposited on the LED chip to which the fluorescent film is attached; The LED chip after dispensing is baked and cured in one go, so that the fluorescent film and the second fluorescent adhesive layer are completely cured at the same time.

[0012] According to one aspect of the above scheme, the steps of mixing fluoride phosphor, nitride red phosphor, and transparent silicone, forming a pre-formed fluorescent film using a coating process, and then subjecting the fluorescent film to a semi-curing treatment include: Fluoride phosphor, nitride red phosphor, and transparent silica gel are mixed to form a fluorescent paste; The fluorescent adhesive is applied to the substrate using a film scraper, and the process parameters of the film scraper are controlled to form a wet film of uniform thickness. The wet film is heated to a semi-cured state to pre-form a fluorescent film that has both mechanical strength and adhesion. The semi-cured fluorescent film is peeled off from the substrate and cut to obtain a film unit that matches the size of the LED chip.

[0013] According to one aspect of the above scheme, during the film forming process, the thickness of the fluorescent film is controlled to be 100μm-250μm; And / or, control the pressure applied by the scraper to be 0.2MPa-0.8MPa.

[0014] According to one aspect of the above scheme, during the process of heating the wet film to achieve a semi-cured state, the temperature of the heating treatment is 80℃-120℃, and the heating time is 3min-8min.

[0015] According to one aspect of the above scheme, the step of attaching the pre-cut fluorescent film to the light-emitting surface of the LED chip includes: The LED chip and the pre-cut fluorescent film unit are aligned using the vision system of the mounting equipment. The fluorescent film unit is accurately pressed onto the light-emitting surface of the LED chip using a mounting component; The ratio of the area of ​​the fluorescent film to the light-emitting surface area of ​​the LED chip is 80%-140%.

[0016] According to one aspect of the above scheme, in the step of accurately pressing the fluorescent film unit onto the light-emitting surface of the LED chip using a mounting component, the area of ​​the fluorescent film is controlled to be larger than the light-emitting surface area of ​​the LED chip, so that the fluorescent film can cover the side of the chip for light emission.

[0017] According to one aspect of the above scheme, the step of mixing fluoride phosphor, nitride red phosphor, and transparent silicone to form a fluorescent paste includes: The fluoride phosphor is mixed with at least a portion of the transparent silica gel for the first time to form a first premixed slurry; The nitride red phosphor is mixed a second time with another portion of the transparent silica gel to form a second premixed slurry; The first premixed slurry and the second premixed slurry are mixed for a third time and stirred under vacuum to form a uniform fluorescent paste.

[0018] According to one aspect of the above scheme, in the steps of the first mixing, the second mixing and the third mixing, the stirring speed is 200r / min-500r / min, the stirring time is 10 minutes-30 minutes, and the vacuum degree of the vacuum stirring is not higher than -0.08MPa.

[0019] According to one aspect of the above scheme, the weight ratio of the fluoride phosphor to the nitride red phosphor is 1:1 to 3:1.

[0020] A second aspect of the present invention is to provide an LED device, which is manufactured by the LED packaging method described in the above technical solution.

[0021] Compared with existing technologies, the LED packaging method based on fluorescent films provided by this invention demonstrates significant improvements in product quality, production efficiency, optical performance, and process feasibility. This method, by employing pre-formed fluorescent films, fundamentally solves the problem of low product consistency and yield caused by uneven phosphor deposition in traditional dispensing processes, resulting in a substantial improvement in color coordinate concentration and spectral yield. In terms of process flow, this invention combines the traditional two dispensing and curing steps, significantly simplifying production steps, effectively shortening the production cycle, and reducing equipment energy consumption and labor costs. Regarding materials and optical design, the film process achieves precise and controllable phosphor distribution, reducing the amount of expensive phosphor used, and through a unique film structure design and red phosphor underlayer layout, effectively improves light extraction efficiency and light output quality. Furthermore, this method has good compatibility with existing production lines, requiring only the addition of film-coating and precision mounting equipment, and possesses excellent prospects for large-scale production. Attached Figure Description

[0022] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic flowchart of an LED packaging method based on a fluorescent film provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of an LED device provided in an embodiment of the present invention; Component symbol explanation in the attached diagram: The package includes a support bracket 10, a bowl 11, an LED chip 20, a fluorescent film 30, and a second fluorescent adhesive layer 40. Detailed Implementation

[0023] To make the objectives, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Several embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of the present invention will be more thorough and complete.

[0024] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0026] Example 1 Please see Figure 1 and Figure 2 The first embodiment of the present invention provides an LED encapsulation method based on a fluorescent film 30, the encapsulation method comprising steps S10-S50: Step S10: Provide a semi-finished LED chip 20 that has completed die bonding and wire bonding, wherein the LED chip 20 is installed in the cup 11 of the packaging bracket 10.

[0027] It should be noted that the purpose of step S10 in this embodiment is to prepare an LED chip 20 platform with completed electrical and mechanical connections. Specifically, die bonding refers to firmly attaching the LED chip 20 to the center of the cup 11 of the package holder 10 using conductive or insulating adhesive, which ensures stable chip fixation and a good heat conduction path. Wire bonding refers to electrically connecting the electrodes on the LED chip 20 to the external pins of the package holder 10 using metal wires (such as gold wires) to provide operating current to the chip.

[0028] The product after completing these two key processes is the semi-finished LED chip 20, and the bowl-shaped structure 11 provides a natural container for the subsequent coating of fluorescent materials.

[0029] In step S20, fluoride phosphor, nitride red phosphor and transparent silicone are mixed and a pre-formed fluorescent film 30 is made by a coating process, and the fluorescent film 30 is subjected to a semi-curing treatment.

[0030] It should be noted that the method shown in this embodiment aims to solve the problem of uneven phosphor deposition in traditional dispensing processes from the source. This step can be further broken down into three key steps: mixing, film forming, and semi-curing.

[0031] First, fluoride phosphor, nitride red phosphor, and transparent silica gel are mixed to prepare a uniform fluorescent paste. The fluoride phosphor (such as K2SiF6:Mn) is used in this process. 4+Red phosphors provide a narrow half-wavelength red light, which is crucial for improving the color rendering index. However, due to their high density, they are a major component prone to sedimentation in traditional processes. Nitride red phosphors can complement these phosphors, broadening the red spectrum. Uniformly mixing them with transparent silica gel (such as high-refractive-index silicone gel) is a prerequisite for obtaining high-quality optical thin films.

[0032] The step of mixing fluoride phosphor, nitride red phosphor, and transparent silica gel to form a fluorescent paste includes: The fluoride phosphor is mixed with at least a portion of the transparent silica gel for the first time to form a first premixed slurry; The nitride red phosphor is mixed a second time with another portion of the transparent silica gel to form a second premixed slurry; The first premixed slurry and the second premixed slurry are mixed for a third time and stirred under vacuum to form a uniform fluorescent paste.

[0033] More specifically, in the steps of the first mixing, the second mixing and the third mixing, the stirring speed is 200 r / min-500 r / min, the stirring time is 10 minutes-30 minutes, and the vacuum degree of the vacuum stirring is not higher than -0.08 MPa.

[0034] Furthermore, the weight ratio of the fluoride phosphor to the nitride red phosphor is 1:1 to 3:1.

[0035] Next, a pre-formed fluorescent film 30 is fabricated using a coating process. A coating machine uses a precision blade to coat the fluorescent adhesive onto the substrate, creating a wet film of uniform thickness and height, with the blade pressure at 0.2 MPa. This pre-formed solid film eliminates the possibility of phosphor settling in the liquid adhesive and uneven distribution due to turbulence, providing a fundamental guarantee for the consistency of the color coordinates of the final LED device.

[0036] Finally, the semi-curing treatment of the fluorescent film 30 serves as a bridge connecting processing and application. Semi-curing (or B-stage curing) involves controlling the heating temperature (e.g., 80℃-120℃) and time (e.g., 3-8 minutes) to induce partial cross-linking of the silicone. In this embodiment, the heating temperature is 100℃ and the time is 5 minutes, resulting in a fluorescent film 30 with a thickness of 100 μm. This gives the fluorescent film 30 sufficient mechanical strength for easy handling, cutting, and mounting, while retaining a certain degree of adhesion and flowability to fuse with the upper colloid interface during final curing, preventing delamination.

[0037] Step S30: The pre-cut fluorescent film 30 is attached to the light-emitting surface of the LED chip 20.

[0038] It should be noted that the step of precisely integrating the pre-prepared standardized optical elements, namely the fluorescent film 30, onto the chip is completed using high-precision mounting equipment, and the process includes alignment and pressing.

[0039] Specifically, attaching a pre-cut fluorescent film 30 to the light-emitting surface of the LED chip 20 means that the film is cut into units that match the chip size. A key design feature is that the area of ​​the fluorescent film 30 is preferably larger than the light-emitting surface area of ​​the LED chip 20 below it. The purpose of this is to ensure that the film can cover the side of the chip, thereby effectively utilizing the blue light emitted from the side of the chip to excite the phosphor and significantly improving the light extraction efficiency.

[0040] The step of attaching the pre-cut fluorescent film 30 to the light-emitting surface of the LED chip 20 includes: The LED chip 20 and the pre-cut fluorescent film 30 unit are aligned using the vision system of the mounting equipment. The fluorescent film 30 unit is accurately pressed onto the light-emitting surface of the LED chip 20 using a mounting component; The ratio of the area of ​​the fluorescent film 30 to the light-emitting surface area of ​​the LED chip 20 is 80%-140%.

[0041] More specifically, in the step of accurately pressing the fluorescent film 30 unit onto the light-emitting surface of the LED chip 20 using the mounting component, the area of ​​the fluorescent film 30 is controlled to be larger than the light-emitting surface area of ​​the LED chip 20, so that the fluorescent film 30 can cover the side of the chip for light emission.

[0042] After precise positioning via the vision system of the mounting equipment, the mounting component smoothly presses the film unit onto the surface of the LED chip 20. This solid, uniform film mounting replaces the traditional first liquid dispensing, fundamentally eliminating sedimentation and simplifying the overall process.

[0043] Step S40: At least one layer of second fluorescent adhesive 40 containing YAG phosphor is applied to the LED chip 20 on which the fluorescent film 30 is attached.

[0044] It should be noted that at least one second fluorescent adhesive layer 40 containing YAG phosphor is applied to the LED chip 20 on which the fluorescent film 30 is attached, in order to construct a hybrid optical structure of lower film and adhesive.

[0045] Specifically, the application of at least one second phosphor layer 40 containing YAG phosphor onto the LED chip 20, which is covered with the phosphor film 30, serves a dual purpose. First, the YAG phosphor, when excited by blue light, produces yellow-green light, which mixes with the red light produced by the lower phosphor film 30 and some of the transmitted blue light to ultimately form high-quality white light. In this embodiment, the structure of placing the long-wavelength phosphor (red phosphor) at the bottom and the short-wavelength phosphor (YAG yellow-green phosphor) at the top helps reduce the reabsorption of short-wavelength fluorescence by the long-wavelength phosphor, thereby improving luminous efficiency. Second, the second phosphor layer 40 fills the gap between the phosphor film 30 and the cup 11 structure, completely encasing the lower phosphor film 30 and the LED chip 20, thus providing stress buffering, mechanical protection, and preventing corrosion from external moisture and pollutants.

[0046] Step S50: The LED chip 20 after dispensing is baked and cured in one go, so that the fluorescent film 30 and the second fluorescent adhesive layer 40 are completely cured at the same time.

[0047] Specifically, during the one-time baking and curing process of the LED chip 20 after dispensing, the lower semi-cured fluorescent film 30 will continue its incomplete cross-linking reaction, while the upper liquid second fluorescent adhesive layer 40 will also begin and complete curing at the same time, and the two will eventually form a tightly bonded and complete optical package.

[0048] The above method successfully combines the two baking processes required by the traditional double-layer dispensing process into a single baking process, significantly shortening the production cycle, reducing equipment usage and energy consumption, thereby improving production efficiency and reducing costs.

[0049] The LED chip 20 prepared by the method shown in this embodiment has a fifth-order yield of 85.20% after testing.

[0050] Compared with existing technologies, the LED packaging method based on a fluorescent film 30 provided by this invention demonstrates significant improvements in product quality, production efficiency, optical performance, and process feasibility. This method, by employing a pre-formed fluorescent film 30, fundamentally solves the problem of low product consistency and yield caused by uneven phosphor deposition and distribution in traditional dispensing processes, resulting in a fundamental improvement in color coordinate concentration and spectral yield. In terms of process flow, this invention combines the traditional two dispensing and curing steps, significantly simplifying production steps, effectively shortening the production cycle, and reducing equipment energy consumption and labor costs. Regarding materials and optical design, the film process achieves precise and controllable phosphor distribution, reducing the amount of expensive phosphor used, and through a unique film structure design and red phosphor underlayer layout, effectively improves light extraction efficiency and light output quality. Furthermore, this method has good compatibility with existing production lines, requiring only the addition of film-coating and precision mounting equipment, and possesses excellent prospects for large-scale production.

[0051] Example 2 The second embodiment of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 100 μm, and the pressure of the scraper is 0.5 MPa.

[0052] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 87.23%.

[0053] Example 3 The third embodiment of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 100 μm, and the pressure of the scraper is 0.8 MPa.

[0054] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 86.32%.

[0055] Example 4 The fourth embodiment of the present invention also provides an LED packaging method based on the fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 150 μm, and the pressure of the scraper is 0.2 MPa.

[0056] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 88.05%.

[0057] Example 5 The fifth embodiment of the present invention also provides an LED packaging method based on the fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 150 μm, and the pressure of the scraper is 0.5 MPa.

[0058] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 90.23%.

[0059] Example 6 The second embodiment of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 150 μm, and the pressure of the scraper is 0.8 MPa.

[0060] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 93.49%.

[0061] Example 7 The seventh embodiment of the present invention also provides an LED packaging method based on the fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 200 μm, and the pressure of the scraper is 0.2 MPa.

[0062] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 98.85%.

[0063] Example 8 The second embodiment of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 200 μm, and the pressure of the scraper is 0.5 MPa.

[0064] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 99.86%.

[0065] Example 9 The second embodiment of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this embodiment, the thickness of the fluorescent film 30 is 200 μm, and the pressure of the scraper is 0.8 MPa.

[0066] After testing, the LED chip 20 made using the fluorescent film 30 shown in this embodiment has a fifth-order yield of 94.67%.

[0067] Comparative Example 1 The first comparative example of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this comparative example, the thickness of the fluorescent film 30 is 250 μm, and the pressure of the scraper is 0.2 MPa.

[0068] After testing, the LED chip 20 made using the fluorescent film 30 shown in this comparative example has a fifth-order yield of 91.64%.

[0069] Comparative Example 2 The second comparative example of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this comparative example, the thickness of the fluorescent film 30 is 250 μm, and the pressure of the scraper is 0.5 MPa.

[0070] After testing, the LED chip 20 made using the fluorescent film 30 shown in this comparative example has a fifth-order yield of 82.61%.

[0071] Comparative Example 3 The third comparative example of the present invention also provides an LED packaging method based on a fluorescent film 30. The method shown in this embodiment is basically similar to the method shown in the first embodiment, except that: In this comparative example, the thickness of the fluorescent film 30 is 250 μm, and the pressure of the scraper is 0.8 MPa.

[0072] After testing, the LED chip 20 made using the fluorescent film 30 shown in this comparative example had a fifth-order yield of 84.32%.

[0073] Table 1 shows the parameter comparison table for Examples 1 to 9 and Comparative Examples 1 to 3.

[0074] Table 1

[0075] Based on the above embodiments and comparative examples, and referring to Table 1, it can be seen that when the film thickness is relatively thin (100 μm), the fifth-order yield of the resulting devices is unsatisfactory regardless of whether a pressure of 0.2 MPa, 0.5 MPa, or 0.8 MPa is applied, with a maximum yield of only 87.23%. This indicates that an excessively thin film layer may not ensure a sufficiently uniform and stable distribution of phosphors, especially denser fluoride red phosphors. When the thickness increases to 150 μm, the overall yield is significantly improved, achieving the best yield of 93.49% at this thickness under a pressure of 0.8 MPa. Furthermore, when the thickness reaches 200 μm, the product yield achieves a breakthrough improvement, further increasing from 98.85% to a near-perfect 99.86% within the pressure range of 0.2 MPa to 0.5 MPa. This demonstrates that a thickness of around 200 μm is an ideal choice for obtaining extremely high consistency.

[0076] After determining the optimal thickness range, the optimization window for the doctor blade pressure was also clarified through data. The impact of pressure variations is particularly critical at the optimal thickness of 200 μm. A maximum yield of 99.86% was achieved at a pressure of 0.5 MPa, indicating that this pressure value strikes an optimal balance between ensuring dense paste filling, membrane flatness, and avoiding excessive compression that could lead to internal stress or component separation. When the pressure increased to 0.8 MPa, the yield dropped to 94.67%, demonstrating that excessively high pressure may negatively impact membrane quality.

[0077] As a contrasting example, the data from the comparative sample (fluorescent film 30, 250 μm thickness) delineates the process boundaries from another perspective. Although the yield reaches 91.64% at 0.2 MPa pressure, it plummets to 82.61% at 0.5 MPa, demonstrating the sensitivity and instability of the process. This collectively indicates that a thickness of 250 μm exceeds the optimization range; excessively thick films may cause increased light loss, internal defects, or incompatibility with other packaging materials, leading to an uncontrollable decline in yield.

[0078] In summary, Example 8 (200μm, 0.5MPa) is a preferred embodiment of the present invention. The above data strongly support determining the preferred range for the thickness of the fluorescent film 30 to be 150μm-200μm, and the preferred doctor blade pressure to be 0.5MPa-0.8MPa. This parameter combination is the core process for solving phosphor sedimentation and achieving ultra-high product consistency.

[0079] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0080] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. An LED packaging method based on a fluorescent film, characterized in that, The encapsulation method includes: Provide LED chip semi-finished products with completed die bonding and wire bonding, wherein the LED chip is installed in the cup of the packaging bracket; Fluoride phosphor, nitride red phosphor and transparent silicone are mixed and preformed into a fluorescent film by a coating process, and the fluorescent film is then semi-cured. The pre-cut fluorescent film is attached to the light-emitting surface of the LED chip; At least one layer of second fluorescent adhesive containing YAG phosphor is deposited on the LED chip to which the fluorescent film is attached; The LED chip after dispensing is baked and cured in one go, so that the fluorescent film and the second fluorescent adhesive layer are completely cured at the same time.

2. The LED packaging method based on a fluorescent film according to claim 1, characterized in that, The steps of mixing fluoride phosphor, nitride red phosphor, and transparent silicone, forming a pre-formed fluorescent film using a coating process, and then subjecting the fluorescent film to a semi-curing treatment include: Fluoride phosphor, nitride red phosphor, and transparent silica gel are mixed to form a fluorescent paste; The fluorescent adhesive is applied to the substrate using a film scraper, and the process parameters of the film scraper are controlled to form a wet film of uniform thickness. The wet film is heated to a semi-cured state to pre-form a fluorescent film that has both mechanical strength and adhesion. The semi-cured fluorescent film is peeled off from the substrate and cut to obtain a film unit that matches the size of the LED chip.

3. The LED packaging method based on a fluorescent film according to claim 2, characterized in that, During the film forming process, the thickness of the fluorescent film is controlled to be 100μm-250μm; And / or, control the pressure applied by the scraper to be 0.2MPa-0.8MPa.

4. The LED packaging method based on a fluorescent film according to claim 2, characterized in that, During the process of heating the wet film to achieve a semi-cured state, the heating temperature is 80℃-120℃ and the heating time is 3min-8min.

5. The LED packaging method based on a fluorescent film according to claim 1, characterized in that, The step of attaching the pre-cut fluorescent film to the light-emitting surface of the LED chip includes: The LED chip and the pre-cut fluorescent film unit are aligned using the vision system of the mounting equipment. The fluorescent film unit is accurately pressed onto the light-emitting surface of the LED chip using a mounting component; The ratio of the area of ​​the fluorescent film to the light-emitting surface area of ​​the LED chip is 80%-140%.

6. The LED packaging method based on a fluorescent film according to claim 5, characterized in that, In the step of accurately pressing the fluorescent film unit onto the light-emitting surface of the LED chip using a mounting component, the area of ​​the fluorescent film is controlled to be larger than the light-emitting surface area of ​​the LED chip, so that the fluorescent film can cover the side of the chip for light emission.

7. The LED packaging method based on a fluorescent film according to any one of claims 1-6, characterized in that, The step of mixing fluoride phosphor, nitride red phosphor, and transparent silica gel to form a fluorescent paste includes: The fluoride phosphor is mixed with at least a portion of the transparent silica gel for the first time to form a first premixed slurry; The nitride red phosphor is mixed a second time with another portion of the transparent silica gel to form a second premixed slurry; The first premixed slurry and the second premixed slurry are mixed for a third time and stirred under vacuum to form a uniform fluorescent paste.

8. The LED packaging method based on a fluorescent film according to claim 7, characterized in that, In the first, second, and third mixing steps, the stirring speed is 200 r / min-500 r / min, the stirring time is 10 minutes-30 minutes, and the vacuum degree of the vacuum stirring is not higher than -0.08 MPa.

9. The LED packaging method based on a fluorescent film according to claim 7, characterized in that, The weight ratio of the fluoride phosphor to the nitride red phosphor is 1:1 to 3:

1.

10. An LED device, characterized in that, The LED device is manufactured by the LED packaging method according to any one of claims 1 to 7.

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