High-brightness five-side light-emitting CSP for double-color-temperature COB and preparation method thereof

Abstract

The present application relates to the technical field of LED packaging, in particular to a high-brightness five-surface light-emitting CSP for double-color-temperature COB and a preparation method thereof, which at least comprises flip-chip LED and fluorescent glue film, five light-emitting surfaces of the flip-chip LED cover the fluorescent glue film; the preparation raw materials of the fluorescent glue film at least include silica gel and KSF, the mass ratio of KSF in the fluorescent glue film is 22-35%, high light efficiency and good light-emitting performance are realized by optimizing the CSP formula system, the problem of low brightness at low color temperature of double-color-temperature COB is solved, and the requirements of substrate-free, multi-layer gradient fluorescent powder structure integration-free and mechanical lock process-free are met.

Description

Technical Field

[0001] This invention relates to the field of LED packaging technology, specifically to a high-brightness five-sided light-emitting CSP for dual-color temperature COB and its preparation method. Background Technology

[0002] In the field of LED (Light Emitting Diode) lighting, dual-color-temperature COB technology enables the switching of light at different color temperatures, meeting users' lighting needs in various scenarios. However, existing dual-color-temperature COB products suffer from insufficient brightness at low color temperatures, affecting their performance in practical applications. While traditional CSP (Chip-on-Package) packaging offers advantages such as small size and high integration, in dual-color-temperature COB applications, the lower color temperature portion typically requires more red light. Existing CSP technology has limitations in red light conversion efficiency, making it difficult to meet the required brightness at low color temperatures. Furthermore, it usually relies on ceramic or metal substrates for electrical connection and heat dissipation. For example, Chinese patent (authorization announcement number CN219497820U) discloses a CSP and LED chip structure with a substrate, which improves brightness through optimized structural design, but it cannot effectively meet the development needs of miniaturized and high-efficiency chip packaging.

[0003] However, due to their typically compact structure and the absence of a substrate and protective layer, CSP packages are more sensitive to moisture, making them prone to blackening due to moisture intrusion, which affects product reliability and lifespan. While some existing technologies employ multi-layer gradient phosphor structures or mechanical locking processes to improve moisture resistance, these processes are complex, requiring multiple coatings and photolithography alignments, and are costly. Summary of the Invention

[0004] This invention provides a high-brightness five-sided light-emitting CSP for dual-color-temperature COB. By optimizing the CSP formulation system, high luminous efficiency and good light-emitting performance are achieved, solving the problem of low brightness at low color temperature in dual-color-temperature COB, and meeting the requirements of substrate-free, multi-layer gradient phosphor structure integration and mechanical locking process.

[0005] The present invention provides a high-brightness five-sided light-emitting CSP for dual-color temperature COB, comprising at least a flip-chip LED and a phosphor film, wherein the five light-emitting surfaces of the flip-chip LED cover the phosphor film; the raw materials for preparing the phosphor film include at least silicone and KSF, wherein the mass percentage of KSF in the phosphor film is 22-35%.

[0006] In one embodiment, the KSF content in the fluorescent film is 25-30% by mass.

[0007] In one embodiment, the KSF content in the fluorescent film is 27-28% by mass.

[0008] In one embodiment, the raw materials for preparing the fluorescent film further include phosphor A with a wavelength of 535 nm and phosphor B with a wavelength of 625 nm.

[0009] In one embodiment, the mass ratio of KSF, phosphor A and phosphor B is (25-30):(25-30):(5-10).

[0010] In one embodiment, the mass ratio of KSF, phosphor A and phosphor B is (27-28):(27-28):(6-8).

[0011] In one embodiment, the flip-chip LED is selected from blue light chips with a wavelength of 450-452.5nm, and is sourced from Sanan Optoelectronics Co., Ltd.

[0012] In one embodiment, the cured silicone has a Shore hardness of D40-56.

[0013] In one embodiment, the cured silicone has a Shore hardness of D48.

[0014] In one embodiment, the refractive index of the cured silicone is 1.540-1.555.

[0015] In one embodiment, the refractive index of the cured silicone is 1.547.

[0016] In one embodiment, the silicone is LED encapsulation silicone, sourced from Guangzhou Huigu New Material Technology Co., Ltd.

[0017] KSF (K2Si6F:Mn) 4+ Phosphors have great potential in improving LED luminous efficacy and color rendering index. However, how to rationally apply KSF to substrate-free, multi-layer gradient phosphor structure integration, and five-sided light-emitting CSP without a protective layer to achieve high luminous efficacy and good luminous performance has not yet been effectively solved. This invention optimizes the mass ratio of KSF in the phosphor film to 22-35%, and further controls the mass ratio of KSF, phosphor A, and phosphor B to (25-30):(25-30):(5-10). The high quantum efficiency and narrow emission peak characteristics of KSF are maximized, effectively improving the luminous efficacy and color rendering index of the CSP. The luminous efficacy can be improved by 25-40% compared to traditional CSPs.

[0018] In one embodiment, the thickness of the fluorescent film is 100-200 μm.

[0019] In one embodiment, the thickness of the fluorescent film is 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, or 200μm.

[0020] The CSP provided by this invention has a five-sided light emission effect, which greatly expands the light emission angle and illumination range, making it suitable for more lighting and display scenarios.

[0021] The CSP provided by this invention uses flip-chip LEDs. The CSP product is obtained by covering the five light-emitting surfaces of the flip-chip LEDs with a fluorescent film. The product has good heat dissipation performance and can effectively prevent blackening caused by moisture intrusion, thereby improving the reliability of the product and extending its service life.

[0022] Another aspect of the present invention provides a method for preparing a high-brightness five-sided light-emitting CSP for dual-color temperature COB, which includes at least the following steps: molding a fluorescent film and a flip-chip LED together, demolding, and cutting.

[0023] In one embodiment, a vacuum is maintained during the molding process.

[0024] In one embodiment, the molding temperature is 90-130°C, the pressure is 4-8 kN, and the time is 4-8 min.

[0025] In one embodiment, the molding temperature is 90°C, the pressure is 5 kN, and the time is 5 min.

[0026] In one embodiment, the shape and size of the molding die are matched with the structural design of the five-sided light-emitting substrate-free and protective-layer CSP.

[0027] In one embodiment, the fluorescent film is in the B-Stage state.

[0028] In one embodiment, the method for preparing the B-Stage fluorescent film is as follows: silica gel, KSF, phosphor A and phosphor B are stirred and mixed in a vacuum environment for 10-20 minutes to obtain a fluorescent composite adhesive, and the fluorescent composite adhesive is used to obtain a B-Stage fluorescent film by extrusion, calendering or coating.

[0029] Regarding the interpretation of "B-Stage" in this invention, the curing reaction of thermosetting resins can be divided into three stages: A, B, and C.

[0030] Stage A: The resin is in the early stage of the reaction. Due to the low degree of polymerization, the molecular weight is still very low, and the material is in a liquid state.

[0031] Stage B: The resin continues to react, with most of the structure exhibiting a linear and partially cross-linked state. The molecular weight is so large that it becomes semi-cured. At this stage, the material can be dissolved by specific solvents and can flow or melt at specific temperatures. In some resins, the reaction is not obvious at this stage.

[0032] C Stage: This stage is the later stage of the resin reaction. The molecular structure presents a network cross-linked structure. The material can no longer be heated and melted, nor can it be dissolved by solvents. It is the final state after the material has cured. The surface is usually non-adhesive and has a stable Tg.

[0033] The CSP product provided by this invention is based on a substrate-free, multi-layer gradient phosphor structure integration and a protective layer-free design, which simplifies the preparation process, reduces production costs and product complexity, and makes it easy to achieve large-scale industrial production.

[0034] Beneficial effects

[0035] 1. This invention provides an integrated RGB LED miniaturized light-emitting element. Through chip-level packaging technology, the provided product can reduce its size and increase its luminous efficiency while meeting the feasibility of miniaturized manufacturing in the terminal module market. This meets the application needs of high-end electronic displays, automotive lighting, smartphone backlights, ultra-thin electronic devices and other fields with high requirements for space, heat dissipation, optical performance and control precision.

[0036] 2. This invention uses flip-chip technology in conjunction with a semi-cured adhesive film. The LED bead can be prepared simply by pressing the semi-cured adhesive film onto the chip, which greatly simplifies the production process, eliminates the need for brackets and gold wires, saves costs, improves production efficiency, and makes it easier to achieve large-scale industrial production and widespread application.

[0037] 3. The dual-color temperature COB high-brightness five-sided light-emitting CSP provided by this invention supports a variety of advanced control methods, including built-in IC control. It can achieve synchronous or independent rhythm change effects at the single component level. It can achieve precise color, brightness and light effect control through programming, and has greater advantages in fields such as smart lighting and displays.

[0038] 4. The high-brightness five-sided light-emitting CSP for dual-color temperature COB provided by the present invention contains one or more flip-chip LEDs and / or driver control chips, which can realize the individual and simultaneous control of blue light, red light and green light under different currents, realize more than 16.77 million color combinations, and have a wide range of applications.

[0039] 5. The high-brightness five-sided light-emitting CSP for dual-color temperature COB provided by this invention reduces light loss during light propagation, improves light output efficiency, and can achieve higher brightness and better light color uniformity. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the structure of a high-brightness five-sided light-emitting CSP for dual-color temperature COB provided in Example 1. In the figure, 1 is a flip-chip LED and 2 is a fluorescent film.

[0041] Figure 2 The spectral morphology diagram of the high-brightness five-sided emitting CSP for dual-color temperature COB provided in Example 1. Detailed Implementation

[0042] Example 1

[0043] See Figure 1 Embodiment 1 of the present invention provides a high-brightness five-sided light-emitting CSP for dual-color temperature COB, including a flip-chip LED and a phosphor film, wherein the five light-emitting surfaces of the flip-chip LED cover the phosphor film.

[0044] The raw materials for preparing the fluorescent film, by mass percentage, include 28% KSF with a wavelength of 632nm, 28% phosphor A with a wavelength of 535nm, 7% phosphor B with a wavelength of 625nm, and silica gel to make up the balance.

[0045] The KSF, phosphor A, and phosphor B are all sourced from Jiangsu Borui Optoelectronics Co., Ltd.

[0046] The flip-chip LED is selected from blue light chips with a wavelength of 450-452.5nm and comes from Sanan Optoelectronics Co., Ltd.

[0047] The silicone used is LED encapsulation silicone, sourced from Guangzhou Huigu New Material Technology Co., Ltd.

[0048] The thickness of the fluorescent film is 150 μm.

[0049] Another aspect of Embodiment 1 of the present invention provides a method for preparing a high-brightness five-sided light-emitting CSP for dual-color temperature COB, comprising the following steps: molding a fluorescent film and a flip-chip LED together, demolding, and cutting.

[0050] The compression molding process is carried out under vacuum, with the vacuum level controlled at 96 kPa.

[0051] The molding temperature is 90℃, the pressure is 5kN, and the time is 5min.

[0052] The shape and size of the molding die are matched with the structural design of the five-sided light-emitting substrate-free and protective-layer-free CSP.

[0053] The fluorescent film is in the B-Stage state.

[0054] The preparation method of the fluorescent film in the B-Stage state is as follows: silica gel, KSF, phosphor A and phosphor B are stirred and mixed in a vacuum environment for 20 minutes to obtain a fluorescent composite adhesive. The fluorescent composite adhesive is coated on a release film and placed in a forced-air drying oven at 80°C for 30 minutes to obtain a fluorescent film in the B-Stage state.

[0055] Example 2

[0056] Example 2 of the present invention provides a high-brightness five-sided light-emitting CSP for dual-color temperature COB and its preparation method. The specific implementation method is the same as that of Example 1, except that, by mass percentage, the raw materials for preparing the fluorescent film include 28% KSF with a wavelength of 632nm, 28% phosphor A with a wavelength of 535nm, 6% phosphor B with a wavelength of 625nm, and the balance is made up with silicone.

[0057] Example 3

[0058] Example 3 of the present invention provides a high-brightness five-sided light-emitting CSP for dual-color temperature COB and its preparation method. The specific implementation method is the same as that of Example 1, except that, by mass percentage, the raw materials for preparing the fluorescent film include 27% KSF with a wavelength of 632nm, 27% phosphor A with a wavelength of 535nm, 8% phosphor B with a wavelength of 625nm, and the remainder is made up with silicone.

[0059] Comparative Example 1

[0060] Comparative Example 1 of the present invention provides a high-brightness five-sided light-emitting CSP for dual-color temperature COB and its preparation method. The specific implementation method is the same as that of Example 1, except that, by mass percentage, the raw materials for preparing the fluorescent film include 14% KSF with a wavelength of 632nm, 40% phosphor A with a wavelength of 535nm, 8% phosphor B with a wavelength of 625nm, and the remainder is made up with silicone.

[0061] Comparative Example 2

[0062] Comparative Example 2 of the present invention provides a high-brightness five-sided luminescent CSP for dual-color temperature COB and its preparation method. The specific implementation method is the same as that of Example 1, except that, by mass percentage, the raw materials for preparing the fluorescent film include 9% KSF with a wavelength of 632nm, 45% phosphor A with a wavelength of 535nm, 8% phosphor B with a wavelength of 625nm, and the remainder is made up with silicone.

[0063] Comparative Example 3

[0064] Comparative Example 3 of the present invention provides a high-brightness five-sided light-emitting CSP for dual-color temperature COB and its preparation method. The specific implementation method is the same as that of Example 1, except that, by mass percentage, the raw materials for preparing the fluorescent film include 19% KSF with a wavelength of 632nm, 35% phosphor A with a wavelength of 535nm, 8% phosphor B with a wavelength of 625nm, and the remainder is made up with silicone.

[0065] Comparative Example 4

[0066] Comparative Example 3 of the present invention provides a high-brightness five-sided light-emitting CSP for dual-color temperature COB and its preparation method. The specific implementation method is the same as that of Example 1, except that, by mass percentage, the raw materials for preparing the fluorescent film include 39% KSF with a wavelength of 632nm, 15% phosphor A with a wavelength of 535nm, 8% phosphor B with a wavelength of 625nm, and the remainder is made up with silicone.

[0067] Performance testing

[0068] 1. The spectral morphology of the product provided in the example was tested using a 300mA current. The obtained spectral morphology diagram is shown in [reference needed]. Figure 2 .

[0069] 2. The products provided in the examples and comparative examples were subjected to the tests listed in Table 1. The test results are shown in Table 1.

[0070] Table 1

[0071]

[0072] Analysis of the data in Table 1 shows that the high-brightness five-sided emitting CSP for dual-color temperature COB provided in Examples 1-3 has better luminous efficacy, light output capability, color temperature, color rendering, and color consistency compared to the products provided in Comparative Examples 1-4.

[0073] (1) The luminous efficacy of the products provided in Examples 1-3 is all >108 lm / W, which is better than that of Comparative Examples 1-4.

[0074] (2) The light flux of the products provided in Examples 1-3 is stable at 97.45~97.69 lm, which is about 6% higher than that of the comparative example (91.13~93.59 lm), indicating that the light conversion efficiency of the examples is better.

[0075] (3) The color temperature range of the products provided in Examples 1-3 is between 2898K (warm white) and 3049K (neutral white), and the color rendering index can reach up to 85.1. The color temperature of Comparative Example 2 is too high (3102K, cool white), which affects comfort. Comparative Examples 3 and 4 have lower color rendering indices (83.9 and 83.6) and warmer color temperatures (2854K), which limits their applicable scenarios.

[0076] (4) The color coordinates of the products provided in Examples 1-3 are more concentrated (x: 0.3937~0.4037, y: 0.3187~0.3265), and the color consistency is better; the comparative examples have a discrete distribution (comparative example 4 x=0.3843, comparative example 3 x=0.4014), which may be due to batch fluctuations.

Claims

1. A high-brightness five-side light emitting CSP for dual color temperature COB, characterized in that, At least including flip LED chip and fluorescent glue film, five light-emitting surfaces of the flip LED chip cover the fluorescent glue film; the preparation raw materials of the fluorescent glue film at least include silica gel and KSF, the mass ratio of KSF in the fluorescent glue film is 22-35%; the preparation raw materials of the fluorescent glue film further include fluorescent powder A with wavelength 535nm and fluorescent powder B with wavelength 625nm; the mass ratio of the KSF, fluorescent powder A and fluorescent powder B is (25-30):(25-30):(5-10); the thickness of the fluorescent glue film is 100-200μm; the Shore hardness of the silica gel after curing is D50-60, and the refractive index of the silica gel after curing is 1.5-1.

6. 2.The high-brightness five-side light emitting CSP for dual-color temperature COB according to claim 1, wherein, The flip LED chip is selected from blue light chip with wavelength 450-452.5nm.

3. A method for manufacturing the high-brightness five-side light emitting CSP for dual-color temperature COB according to any one of claims 1-2, characterized in that, At least including the following steps: molding the fluorescent glue film and the flip LED chip by molding, demolding and cutting. 4.The method for preparing a high-brightness five-side light emitting CSP for dual-color temperature COB according to claim 3, characterized in that, The molding temperature is 90-130℃, the pressure is 4-8kN, and the time is 4-8min. 5.The method for preparing a high-brightness five-side light emitting CSP for dual-color temperature COB according to claim 3, characterized in that, The fluorescent glue film is in B-Stage state.

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