Low-blue-light yellow-light LED device and preparation method thereof

Abstract

The invention relates to the field of LED packaging, in particular to a low-blue-light yellow-light LED device and a preparation method thereof. The solid crystal glue is arranged on the packaging carrier; a chip, wherein the chip is bonded on the solid crystal glue; the fluorescent powder layer covers the chip and is formed by mixing narrow-band yellow green powder (540-550 nm), narrow-band orange yellow powder (570-600 nm) and transparent silica gel; and the packaging colloid covers the surface of the fluorescent powder layer to form a heat dissipation structure. Compared with the prior art, the blue light component of the finally output yellow light is reduced to 0.01%-0.03%, which is significantly lower than the blue light proportion (generally greater than 5%) of the traditional blue light chip and fluorescent powder scheme, and the human eye health risk is reduced from the source.

Description

Technical Field

[0001] This application relates to the field of LED packaging technology, and in particular to a low blue light yellow light LED device and its preparation method. Background Technology

[0002] Yellow LEDs are light-emitting diodes whose emission spectrum is concentrated in the yellow band (wavelength typically 570-590nm). Their color attribute lies between green (500-560nm) and red (620-750nm), falling within the visible light range. Compared to common blue and white LEDs, yellow LEDs are more focused on applications requiring specific spectra, such as plant lighting, medical phototherapy, and specialized displays.

[0003] In existing technologies, the main methods for fabricating LED light sources include directly emitting yellow light from GaALAs and GaAsP ternary chips, or achieving yellow light output through a combination of blue light chips and phosphors.

[0004] However, all of these methods have the problem of excessive blue light content, which poses a potential threat to human eye health. Summary of the Invention

[0005] This application provides a low blue light yellow LED device and its preparation method to solve the technical problem that the existing technology has excessive blue light content, which poses a potential threat to human eye health.

[0006] In a first aspect, this application provides a low blue light yellow light LED device, comprising:

[0007] Encapsulation carrier;

[0008] Diode bond adhesive disposed on the encapsulation carrier;

[0009] Chip, the chip being bonded to the die bond adhesive;

[0010] The phosphor layer covering the chip is composed of a mixture of narrow-wavelength yellow-green phosphor (540-550nm), narrow-wavelength orange-yellow phosphor (570-600nm), and transparent silicone.

[0011] An encapsulating colloid is used to cover the surface of the phosphor layer to form a heat dissipation structure.

[0012] Furthermore, the packaging carrier is one of a packaging bracket, a ceramic substrate, and a COB substrate, and the die bond adhesive is a thermally conductive insulating adhesive layer or a metal compound layer. The thermally conductive insulating adhesive layer is disposed on the packaging bracket, and the metal compound layer is disposed on the ceramic substrate or the COB substrate.

[0013] Furthermore, the packaging bracket is one of SMD2835, SMD3030, SMD5050, SMD707, and SMD1A1A, and the chip is an NGAIN blue and violet light chip.

[0014] Furthermore, the packaging bracket is also provided with a positive bracket pin and a negative bracket pin. The positive bracket pin is bonded to the chip through a gold wire, and the negative bracket pin is directly connected to the thermally conductive insulating adhesive layer to form a closed loop.

[0015] Furthermore, the transparent silicone is composed of high-solids-content adhesive and low-viscosity adhesive, and the mass ratio of narrow-band yellow-green powder, narrow-band orange-yellow powder, high-solids-content adhesive and low-viscosity adhesive in the phosphor layer is 5:1:0.35:3.5.

[0016] Furthermore, the peak wavelength of the phosphor layer is 570-585nm, and the main wavelength is 575-595nm.

[0017] Secondly, this application also provides a method for fabricating a low blue light yellow LED, comprising the following steps:

[0018] S1. Provide blue and purple LED chips with peak wavelengths of 400-470nm;

[0019] S2. Prepare a mixture containing phosphors, the mixture comprising narrow-wavelength yellow-green phosphor with a peak wavelength of 540-550nm and narrow-wavelength orange-yellow phosphor with a peak wavelength of 570-600nm;

[0020] S3. A uniform phosphor layer is formed on the chip by means of phosphor deposition process or by making phosphor film;

[0021] S4. Store after high-temperature curing.

[0022] Furthermore, step S1 is preceded by:

[0023] Choose between an SMD bracket or a COB substrate;

[0024] The blue and purple LED chips are bonded to the thermally conductive insulating adhesive on the SMD bracket or to the metal compound on the COB substrate.

[0025] Furthermore, step S3 also includes:

[0026] Phosphors are uniformly coated onto the chip using dispensing and powder spraying equipment, or phosphors are made into films and attached to the chip.

[0027] Furthermore, step S4 also includes:

[0028] Before storage, place the product in a constant temperature and humidity chamber to bake and cure the adhesive.

[0029] The technical solution provided in this application has the following advantages compared with the prior art:

[0030] This application uses a GaN-based blue-violet light chip (400-470nm) to excite a dual-band phosphor layer (yellow-green phosphor 540-550nm and orange-yellow phosphor 570-600nm). Through precise wavelength conversion, the blue light component of the final output yellow light is reduced to 0.01%-0.03%, which is significantly lower than the blue light ratio of traditional blue light chips and phosphor solutions (usually >5%), thus reducing the risk to human eye health from the source. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] To more clearly illustrate the technical solutions in the embodiments of this application 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.

[0033] 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.

[0034] Figure 1 This is a schematic diagram of the structure of a low blue light yellow light LED device provided in an embodiment of this application;

[0035] Figure 2 for Figure 1 Exploded view;

[0036] Figure 3 for Figure 1 A sectional view;

[0037] Figure 4 A schematic diagram of another low blue light yellow light LED device provided in this application embodiment;

[0038] Figure 5 for Figure 4 Exploded view;

[0039] Figure 6 The light source test spectrum of Sample 1 provided in the embodiments of this application;

[0040] Figure 7 The light source test spectrum of Sample 2 provided in the embodiments of this application;

[0041] Figure 8 The light source test spectrum of sample three provided in the embodiments of this application;

[0042] Figure 9 This is a schematic flowchart of a low blue light yellow light LED fabrication method provided in an embodiment of this application.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Packaging carrier; 11. Packaging bracket; 111. Thermally conductive insulating adhesive layer; 112. Positive electrode bracket pin; 113. Negative electrode bracket pin; 12. COB substrate; 121. Metal compound layer;

[0045] 2. Phosphor layer;

[0046] 3. Chips;

[0047] 4. Encapsulating colloid. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0051] To address the technical problem of excessive blue light content in existing technologies posing a potential threat to human eye health, this application provides a low-blue-light yellow LED device and its fabrication method. It employs a GaN-based blue-violet LED chip (400-470nm) to excite a dual-band phosphor layer (yellow-green phosphor 540-550nm and orange-yellow phosphor 570-600nm). Through precise wavelength conversion, the blue light content of the final output yellow light is reduced to 0.01%-0.03%, significantly lower than the blue light content of traditional blue LED chips and phosphor solutions (typically >5%), thus reducing the risk to human eye health from the source.

[0052] Please see Figures 1 to 8 This application provides a low blue light yellow LED device and its fabrication method, comprising: an encapsulation carrier 1; a die bond adhesive disposed on the encapsulation carrier 1; a chip 3 bonded to the die bond adhesive; a phosphor layer 2 covering the chip 3, which is composed of a mixture of narrow-wavelength yellow-green phosphor (540-550nm), narrow-wavelength orange-yellow phosphor (570-600nm), and transparent silicone; and an encapsulation colloid 4 covering the surface of the phosphor layer 2 to form a heat dissipation structure.

[0053] Specifically, in this embodiment, the chip 3 mounting area is formed on the surface of the packaging carrier 1 through stamping or etching processes to ensure that the electrode lead layout meets the bonding requirements. Epoxy resin or silicone-based thermally conductive adhesive is coated on the carrier surface and pre-cured at 80°C for 30 minutes to form an insulating adhesive layer. Next, in COB packaging, an aluminum nitride (AlN) layer with a thickness of 50-100 μm is deposited on the carrier using a magnetron sputtering process, followed by annealing at 600°C in a nitrogen atmosphere to enhance adhesion.

[0054] Bonding steps: Place the GaN-based blue-violet light chip 3 on the thermally conductive layer and connect the electrodes of chip 3 to the carrier pins by gold wire ball bonding; or use eutectic bonding process to achieve electrical connection between chip 3 and carrier in a vacuum reflow oven.

[0055] Mixing and coating: Add narrow-wave yellow-green powder (peak value 546nm) and narrow-wave orange-yellow powder (peak value 575nm) to transparent silicone in proportion, and mix in a vacuum mixer at 1500rpm for 20 minutes; use a dispensing machine to evenly cover the surface of chip 3 with the mixed colloid, control the thickness to be 1.2 times the height of chip 3, let it stand to defoam, and then pre-cur at 60℃ for 10 minutes.

[0056] Encapsulation process: High-refractive-index silicone (refractive index ≥ 1.53) is poured onto the surface of phosphor layer 2. After molding, it is cured at 150°C for 2 hours to form a transparent dome structure that completely covers phosphor layer 2, realizing a closed-loop heat conduction path of chip 3 → phosphor layer 2 → encapsulation colloid 4 → carrier.

[0057] Compared with the prior art, this application has the following advantages:

[0058] (1) A uniformly mixed layer of dual-band phosphor (yellow-green phosphor + orange-yellow phosphor) and silicone directly covers the blue light chip 3, realizing the full absorption and conversion of short-wavelength blue light (400-470nm). The blue light component in the output spectrum is suppressed to a level close to undetectable, completely solving the problem of blue light hazards of traditional yellow LEDs.

[0059] (2) Transparent silicone is used as a dispersion medium to improve the excitation efficiency of phosphor and reduce light scattering loss; at the same time, after curing, the colloid tightly covers the phosphor layer 2, and the heat of the chip 3 is quickly discharged through the carrier to avoid light decay and wavelength shift caused by high temperature.

[0060] like Figure 2 and Figure 5 As shown, the encapsulation carrier 1 is one of the encapsulation support 11, ceramic substrate (not shown in the figure), and COB substrate 12. The die bond adhesive is a thermally conductive insulating adhesive layer 111 or a metal compound layer 121. The thermally conductive insulating adhesive layer 111 is disposed on the encapsulation support 11, and the metal compound layer 121 is disposed on the ceramic substrate or COB substrate 12.

[0061] Specifically, in this embodiment, the packaging bracket 11 is matched with a thermally conductive insulating adhesive layer 111. Silicone thermally conductive adhesive is dotted onto the top of the bracket, covering the metal substrate, and cured at 150°C to form a continuous insulating layer. The chip 3 is bonded to the surface of the thermally conductive insulating adhesive layer 111 using silver paste, and the electrodes are wire-bonded with gold wire. The ceramic / COB substrate 12 is matched with a metal compound layer 121. A titanium nitride (TiN) or silicon carbide (SiC) thin film is magnetron sputtered onto the substrate surface. The chip 3 is eutectic bonded to the metal compound layer 121 using a gold-tin alloy solder. The thermally conductive insulating adhesive layer 111 serves as an electrical isolation medium, isolating the potential difference between the chip 3 and the metal bracket, while simultaneously transferring heat from the chip 3 to the bracket's heat dissipation fins. The metal compound layer 121 serves as a high thermal conductivity interface, directly bridging the chip 3 and the ceramic / COB substrate 12, forming an ultra-low thermal resistance path from chip 3 to the compound layer to the substrate.

[0062] Furthermore, the ceramic substrate in this embodiment can be ceramic 5050 or ceramic 7070. In other embodiments, other types of substrates can also be used, depending on the actual situation.

[0063] In one available embodiment, the package holder 11 is one of SMD2835, SMD3030, SMD5050, SMD707, and SMD1A1A, and the chip 3 is an NGAIN blue and purple light chip 3.

[0064] Specifically, this embodiment selects a standard bracket based on the device power requirements. For low power (0.1-0.5W): an SMD2835 bracket with a cup depth of 0.2mm is used; for medium power (0.5-1W): an SMD3030 bracket is used with a 40% increase in cup area; for high power (1-3W): an SMD5050 or SMD7070 bracket with a dual-electrode parallel design is used; for ultra-high power (>3W): an SMD1A1A bracket is used with a copper substrate thickness increased to 0.8mm. The NGAIN blue / violet light chip 3 is bonded to the center of the bracket cup using silver paste. After curing at 180℃, gold wire bonding connects the chip 3 to the bracket pins. A phosphor-silicone mixture is dotted to cover the chip 3, filling 90% of the bracket cup volume. The encapsulating colloid 4 is then poured and heat-cured, sealing the edges of the colloid with the bracket pins.

[0065] like Figure 2-3 As shown, the package bracket 11 is also provided with a positive bracket pin 112 and a negative bracket pin 113. The positive bracket pin 112 is bonded to the chip 3 through a gold wire, and the negative bracket pin 113 is directly connected to the thermally conductive insulating adhesive layer 111 to form a closed circuit.

[0066] Specifically, a pad area is provided on the top of the positive electrode support pin 112, and the positive electrode of the chip 3 is connected to it by ball bonding via gold wire. The surface of the negative electrode support pin 113 is in direct physical contact with the thermally conductive insulating adhesive layer 111 (containing conductive silver powder). After the adhesive layer cures, a conductive path is formed between the pin and the bottom of the chip 3. The thermally conductive insulating adhesive layer 111 is mixed with alumina (thermally conductive phase) and silver powder (conductive phase), wherein the silver powder is distributed in a gradient along the direction of the negative electrode pin, realizing the conductive layer between the insulating layer on the back of the chip 3 and the negative electrode pin. Gradient pressure curing causes the conductive silver powder to accumulate in the negative electrode pin, while other areas of the adhesive remain insulating. Through the above structure, this embodiment forms a complete current loop of chip 3 positive electrode → gold wire → positive electrode pin → external circuit → negative electrode pin → thermally conductive insulating adhesive layer 111 → chip 3 negative electrode. It only requires a single positive gold wire (traditionally, double gold wires are required), which can eliminate the risk of gold wire crossing short circuit and spatial interference and reduce wire impedance.

[0067] In one available embodiment, the transparent silicone is composed of a high-solids-content adhesive and a low-viscosity adhesive, and the mass ratio of narrow-band yellow-green powder, narrow-band orange-yellow powder, high-solids-content adhesive and low-viscosity adhesive in the phosphor layer 2 is 5:1:0.35:3.5.

[0068] Specifically, in this embodiment, the components are weighed according to the ratio of narrow-wavelength yellow-green phosphor: narrow-wavelength orange-yellow phosphor: high-solids-content adhesive: low-viscosity adhesive = 5:1:0.35:3.5. The orange-yellow phosphor dominates the main peak position (locking in 575-595nm), while the yellow-green phosphor fills the short-wavelength gap and suppresses the emission of blue light from 400-480nm. Simultaneously, the high / low viscosity adhesives synergistically regulate the refractive index of the adhesive layer (1.50-1.53), reducing interfacial light loss and narrowing the full width at half maximum (FWHM) to ≤125nm. The low-viscosity adhesive penetrates and fills the gaps between the phosphors, eliminating sedimentation and stratification; the high-solids-content adhesive forms a rigid framework, increasing the heat distortion temperature to >180℃.

[0069] It is understood that, in addition to the above-mentioned ratio, the composition ratio of the phosphor layer 2 in this embodiment can also be 11.4:2.2:0.4:4, 5:1:0.3:3 and 5.23:4.75:0.45:4.5, etc. The specific ratio can be selected according to the actual situation.

[0070] The 11.4:2.2:0.4:4 ratio significantly increases the proportion of narrow-wavelength orange-yellow powder (yellow-green powder: orange-yellow powder ≈ 5.2:1), forming a long-wavelength radiation-dominant spectrum. High-solids-content adhesive (0.4 parts) and low-viscosity adhesive (4 parts) synergistically construct a high-powder-loading system (powder content > 80%). The colloid forms a microlens array in the powder gaps, enhancing the 590-600nm long-wavelength radiation of the orange-yellow powder. The 5:1:0.3:3 ratio, low... The colloidal ratio reduces scattering loss and increases the short-wavelength photon release rate of the yellow-green powder; with a ratio of 5.23:4.75:0.45:4.5, the yellow-green powder (540-550nm) dominates short-wavelength radiation, covering the chlorophyll a absorption band, while the orange-yellow powder (570-600nm) enhances long-wavelength emission, locking in the amber spectrum that the human eye is sensitive to; the colloidal ratio (0.45:4.5) forms an optical microcavity, enhancing the peak intensity of yellow light in the 570-590nm range.

[0071] In one available embodiment, the peak wavelength of the phosphor layer 2 is 570-585 nm, and the dominant wavelength is 575-595 nm.

[0072] Specifically, narrow-wavelength yellow-green phosphors (emission spectral center 540-550nm) and narrow-wavelength orange-yellow phosphors (emission spectral center 570-600nm) are carefully selected, and their emission peaks are merged to form a single main peak structure through optimized mass ratio. The powders are premixed and ground to a submicron particle size distribution, and then injected into transparent silica gel in stages with low-speed stirring to avoid wavelength shift caused by crystal breakage. The thickness of phosphor layer 2 is controlled within 1.1-1.3 times the size of chip 3, so that the excitation path length of the blue-violet chip 3 (400-470nm) is balanced with the absorption cross-section of the phosphor, ensuring maximum conversion efficiency.

[0073] Furthermore, by Figure 6-8 As shown, the light source spectrum of this embodiment was tested in three samples. Sample 1 had a peak wavelength of 575 nm and a dominant wavelength of 579.4 nm; Sample 2 had a peak wavelength of 574 nm and a dominant wavelength of 578.7 nm; and Sample 3 had a peak wavelength of 571 nm and a dominant wavelength of 579.4 nm. Data from the three samples shows that the dominant and peak wavelengths of all samples fall within the range of this embodiment. The phosphor combination (narrow-band yellow-green phosphor + narrow-band orange-yellow phosphor) effectively absorbs blue-violet light from chip 3 (400-470 nm) and converts it into yellow light. The color temperature (2656-2738 K) is stable at 1800-3100 K, meeting the requirements of healthy lighting scenarios, i.e., reducing blue light hazards.

[0074] In another embodiment, such as Figure 4-5As shown, this embodiment also provides an LED device formed by COB packaging technology, which includes a COB substrate 12, a metal compound layer 121, a phosphor layer 2, an encapsulating colloid 4, and a chip 3. The metal compound layer 121 is disposed on the COB substrate 12, the chip 3 is bonded to the metal compound layer 121, the phosphor layer 2 is disposed on the chip 3, and the phosphor layer 2 is covered by the encapsulating colloid 4 to form a heat dissipation structure.

[0075] Specifically, a high thermal conductivity aluminum substrate is selected, and an insulating layer is formed by anodizing the surface. A precision circuit pattern is then formed by laser etching. A silver plating layer with a thickness ≥3μm is applied to the electrode area to reduce contact resistance. A titanium nitride (TiN) film with a thickness of 30±5μm is magnetron sputtered onto the substrate electrode area and activated by argon plasma bombardment. The surface is then annealed in a vacuum furnace at 450℃ for 1 hour to form the bonding interface for chip 3. Gold-tin solder is pre-placed on the back of chip 3 and mounted onto the metal compound layer 121. Eutectic bonding is completed by step heating to 320℃ under nitrogen protection. Narrow-band yellow-green and orange-yellow phosphors are mixed in a specific ratio, dispersed in silicone, and dotted to cover the surface of chip 3. The mixture is then spin-coated to a thickness of 0.5mm and pre-cured at 80℃. A high-refractive-index silicone encapsulates and coats the phosphor layer 2. The layers are then molded to form a dome lens structure and heat-cured at 150℃ for 2 hours, fusing and sealing the colloid with the substrate edges. Compared to SMD packaging technology, COB packaging technology has the advantage that the entire process of metal layer sputtering → eutectic bonding → fluorescent coating → colloidal encapsulation is completed on a single production line, greatly shortening the production cycle.

[0076] Please see Figure 9 This application also provides a method for fabricating a low blue light yellow LED, comprising the following steps:

[0077] S1. Provide blue and purple LED chips with peak wavelengths of 400-470nm;

[0078] S2. Prepare a mixture containing phosphors, the mixture containing narrow-band yellow-green phosphor with a peak wavelength of 540-550nm and narrow-band orange-yellow phosphor with a peak wavelength of 570-600nm;

[0079] S3. A uniform phosphor layer 2 is formed on the chip 3 by means of phosphor deposition process or by making phosphor film;

[0080] S4. Store after high-temperature curing.

[0081] Specifically, this embodiment uses a GaN-on-sapphire epitaxial wafer, and forms a micron-level electrode pattern through photolithography etching; wafer-level sorting of chips 3 with wavelengths between 400-470nm, removing units with wavelength deviations >2nm; narrow-wavelength yellow-green powder and narrow-wavelength orange-yellow powder are weighed according to the target spectral requirements, dry-mixed and ball-milled in a nitrogen glove box for 30 minutes, and the powder particle size is controlled at D50 = 12±2μm; chip 3 is placed in a vacuum settling chamber, and the phosphor mixture is uniformly covered on the surface by electrostatic spraying, or the mixture is rolled with transparent silicone into a flexible film with a thickness of 0.2mm, laser-cut to match the size of chip 3, and vacuum adsorbed and attached to the surface of chip 3; pre-curing at 80℃ for 30 minutes to lock the powder layer position → main curing at 150℃ for 2 hours → slow cooling at 50℃ to eliminate internal stress; the finished product is placed in a nitrogen-filled drying oven, with humidity <5%RH, and stored in a light-proof and shockproof environment.

[0082] In one available embodiment, step S1 is further preceded by the following steps:

[0083] Choose an SMD bracket or a COB substrate 12; bond the blue and purple LED chips 3 to the thermally conductive insulating adhesive on the SMD bracket or the metal compound on the COB substrate 12.

[0084] Specifically, the SMD bracket pretreatment process is as follows: the metal lead frame is acid-washed to remove oxides, and the cup area is roughened by laser etching; thermally conductive insulating adhesive (epoxy resin-based) is dotted onto the top of the cup and pre-cured at 150℃ to form a smooth bonding surface; the COB substrate 12 pretreatment process is as follows: an aluminum nitride (AlN) transition layer is magnetron sputtered onto the surface of the ceramic substrate and activated by argon ion bombardment; a metal compound layer 121 (TiN or SiC) is pulsed laser deposited on the electrode area with a thickness uniformity of ≤±2μm. In the SMD bracket scenario, the blue and purple light chips 3 are bonded to the insulating adhesive layer with silver paste, and a precision fixture is used to pressurize the contact area to >95%; gold wire ball bonding connects the positive electrode of chip 3 to the bracket pins with an arc height tolerance of ±5μm; in the COB substrate 12 scenario, chip 3 is flip-chip bonded to the metal compound layer 121, and gold-tin solder is pre-placed at the interface; vacuum reflow soldering is performed with stepped temperature rise (220℃→280℃), and vertical pressure is applied to achieve eutectic bonding.

[0085] In one available embodiment, step S3 further includes the following steps:

[0086] Phosphor powder is uniformly coated onto chip 3 using a dispensing machine and a powder spraying machine, or a film of phosphor powder is made and attached to chip 3.

[0087] Specifically, the dispensing machine is equipped with a precision screw valve to apply silicone substrate along the outer contour of chip 3;

[0088] The powder sprayer simultaneously atomizes and sprays a mixture of phosphors, with an air pressure control range of 0.2-0.5 MPa and a powder landing accuracy of ±0.1 mm. For different chip sizes, it automatically adjusts the spraying angle and dispensing speed to maintain a constant powder-to-adhesive volume ratio. The phosphor and UV-curable adhesive are mixed and calendered into a film with a thickness of 0.15-0.25 mm. After UV pre-curing, it is die-cut to match the chip size. The film is placed on a vacuum chuck, precisely aligned with the center of the chip, and stepped pressure is applied to achieve interface sealing. This coating process, employing "synchronous dynamic control of powder and adhesive," overcomes the bottleneck of traditional step-by-step operations, achieving nanometer-level coverage accuracy and improving operational efficiency. The film process enhances the interfacial bonding strength, thermal stability, and environmental resistance of the encapsulated product.

[0089] In one available embodiment, step S4 further specifically includes the following steps:

[0090] Before storage, place the product in a constant temperature and humidity chamber to bake and cure the adhesive.

[0091] Specifically, the encapsulated LED devices are placed in a programmable temperature and humidity chamber, with temperature and humidity parameters set. A multi-directional airflow circulation system within the chamber ensures temperature uniformity of ≤±0.5℃ and humidity gradient of ≤5%RH. The temperature setting matches the glass transition range of the colloidal material, with heating in three stages (low-temperature dehumidification → medium-temperature cross-linking → high-temperature stabilization). Humidity is adjusted in real-time according to the release rate of curing reaction byproducts to suppress microbubble formation. The LED devices are vertically inserted into the support frame, with leads suspended to avoid heat buildup. Nitrogen purging is performed throughout the baking process, and the devices are transferred to dry storage within 30 minutes of completion. This method significantly improves the curing quality of the LED encapsulated products.

[0092] 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.

[0093] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0094] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0095] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0096] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0097] In the description of this specification, the 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 this application. The illustrative expressions of the above terms in this specification should not be construed as necessarily referring 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. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0098] 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.

[0099] The above description describes specific embodiments 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. A low blue light yellow light LED device, characterized in that, include: Encapsulation carrier; Diode bond adhesive disposed on the encapsulation carrier; Chip, the chip being bonded to the die bond adhesive; The phosphor layer covering the chip is composed of a mixture of narrow-wavelength yellow-green phosphor (540-550nm), narrow-wavelength orange-yellow phosphor (570-600nm), and transparent silicone. An encapsulating colloid is used to cover the surface of the phosphor layer to form a heat dissipation structure.

2. The apparatus according to claim 1, characterized in that, The encapsulation carrier is one of an encapsulation bracket, a ceramic substrate, and a COB substrate. The die bond adhesive is a thermally conductive insulating adhesive layer or a metal compound layer. The thermally conductive insulating adhesive layer is disposed on the encapsulation bracket, and the metal compound layer is disposed on the ceramic substrate or the COB substrate.

3. The apparatus according to claim 2, characterized in that, The packaging bracket is one of SMD2835, SMD3030, SMD5050, SMD707, and SMD1A1A, and the chip is an NGAIN blue and violet light chip.

4. The apparatus according to claim 3, characterized in that, The packaging bracket is also provided with a positive bracket pin and a negative bracket pin. The positive bracket pin is bonded to the chip through a gold wire, and the negative bracket pin is directly connected to the thermally conductive insulating adhesive layer to form a closed loop.

5. The apparatus according to claim 1, characterized in that, The transparent silicone is composed of high-solids-content adhesive and low-viscosity adhesive, and the mass ratio of narrow-wave yellow-green powder, narrow-wave orange-yellow powder, high-solids-content adhesive and low-viscosity adhesive in the phosphor layer is 5:1:0.35:3.

5.

6. The apparatus according to claim 5, characterized in that, The peak wavelength of the phosphor layer is 570-585nm, and the main wavelength is 575-595nm.

7. A method for fabricating a low blue light yellow LED, characterized in that, Includes the following steps: S1. Provide blue and purple LED chips with peak wavelengths of 400-470nm; S2. Prepare a mixture containing phosphors, the mixture comprising narrow-wavelength yellow-green phosphor with a peak wavelength of 540-550nm and narrow-wavelength orange-yellow phosphor with a peak wavelength of 570-600nm; S3. A uniform phosphor layer is formed on the chip by means of phosphor deposition process or by making phosphor film; S4. Store after high-temperature curing.

8. The method according to claim 7, characterized in that, Step S1 is preceded by: Choose between an SMD bracket or a COB substrate; The blue and purple LED chips are bonded to the thermally conductive insulating adhesive on the SMD bracket or to the metal compound on the COB substrate.

9. The method according to claim 7, characterized in that, Step S3 also includes: Phosphors are uniformly coated onto the chip using dispensing and powder spraying equipment, or phosphors are made into films and attached to the chip.

10. The method according to claim 7, characterized in that, Step S4 also includes: Before storage, place the product in a constant temperature and humidity chamber to bake and cure the adhesive.

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