Preparation process of high light efficiency, high color rendering index and high weather resistance multi-structure COB light source

Abstract

The application belongs to the technical field of lighting appliances and its packaging preparation, and particularly relates to a high-light-efficiency high-luminance high-weather-resistance multi-structure COB light source preparation process. A multi-layer configuration high-weather-resistance COB light source is obtained through the process, the lower layer selects high-transparency high-temperature-resistance silica gel to ensure the reliability and temperature resistance of the light source, the light source chip and the fluorescent powder are layered packaged to reduce the influence of high heat generated by the chip light emission on the thermal quenching reaction of the fluorescent powder particles, so that the fluorescent powder particles always maintain a relatively high emission efficiency. The upper protective layer selects high-transparency high-air-tightness silica gel to solve the shortcomings of the conventional COB light source, such as low-refraction silica gel, soft and high-moisture and oxygen-permeation rate, poor resistance to vulcanization, and the like, to block the moisture from entering the light source, so that the middle fluorescent powder layer can always work in a relatively dry and clean environment, to solve the application pain points of the fluoride fluorescent powder or quantum dot fluorescent powder, such as poor temperature resistance and poor moisture resistance, and the like; and the light source emits light more uniformly and is more closely connected internally.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lighting appliances and its packaging preparation, and particularly relates to a high-light-efficiency high-luminous-index high-weather-resistance multi-structure COB light source preparation process. BACKGROUND

[0002] COB has the advantages of soft light, simple circuit design, high cost-effectiveness, system space saving, high thermal conductivity, high light density output and high light quality, and its obvious advantages in commercial lighting make it the mainstream solution for directional lighting. LED light sources have been widely used in various lighting scenarios. Currently, the main packaging forms of LED are SMD, COB and CSP. The traditional COB packaging preparation process is a packaging method in which multiple LED chips are directly fixed on a circuit substrate.

[0003] At present, commercial WLEDs are generally realized by the method of "blue chip + red phosphor + green phosphor". The research on blue GaN chips has entered a bottleneck stage. It is extremely costly to significantly improve the light efficiency of products by improving the performance of chips. In terms of phosphor, fluoride red phosphor and quantum dot green phosphor have great advantages in excitation efficiency compared with conventional phosphor, but their temperature and humidity resistance are poor, which restricts the wide application of these two kinds of phosphor, resulting in that these two high-performance phosphors are currently used in low-power LED backlight devices.

[0004] In addition, the traditional COB packaging is a packaging method in which multiple LED chips are directly fixed on a circuit substrate. The moisture in the air and the high heat generated by the bottom chip during work will affect the phosphor particles.

[0005] Therefore, in view of the above technical problems and defects, such as simple packaging process, poor temperature and humidity resistance, which restricts the wide application of these two kinds of phosphor, resulting in that these two high-performance phosphors are currently used in low-power LED backlight devices, and the moisture in the air and the high heat generated by the bottom chip during work will affect the phosphor particles, it is urgent to design and develop a high-light-efficiency high-luminous-index high-weather-resistance multi-structure COB light source preparation process. SUMMARY

[0006] The present application aims to provide a high-light-efficiency high-luminous-index high-weather-resistance multi-structure COB light source preparation process.

[0007] The purpose of the present application is achieved by the process comprising the following steps:

[0008] Die bonding treatment: using an LED automatic die bonder to bond the LED blue chips on the COB substrate in the designed order through die bonding glue, and then completely curing the die bonding glue by heating in an oven to complete the fixation of the chips.

[0009] Wire bonding process: Using an automatic LED wire bonding machine, the LED blue light chip is connected to the electrodes via gold wires in the design sequence, and then connected to the positive and negative electrodes on the COB substrate to form a power path;

[0010] Inner ring of the dam: The flexible dam-building adhesive and small-diameter needles are used, and the LED automatic dam-building machine is used to carry out the dam-building operation according to the program.

[0011] Bottom protective adhesive: High light transmittance and high temperature resistance LED encapsulation silicone is used. After stirring and degassing, the transparent LED encapsulation silicone is evenly covered on the bottom of the substrate using a dispensing machine or spraying machine. The adhesive completely wraps the light source bonding wire arc, so that the bonding wire and the chip are in the same protective adhesive layer.

[0012] Powder spraying: High-efficiency fluoride phosphors or quantum dot phosphors with high excitation color gamut are used, and the phosphors are adjusted and matched to obtain different color temperatures and color rendering index requirements. The phosphors are then dissolved in an organic diluent and stirred evenly. The phosphors are then evenly sprayed onto the bottom protective adhesive layer using a powder spraying device. After heating and curing, the diluent in the original liquid phosphor layer evaporates, and the phosphor colloid solidifies to form an intermediate phosphor layer. After the adhesive is removed, it is atomized and sprayed onto the light-emitting area. The bottom chip is powered on to excite blue light, which is transmitted and reflected on the bottom adhesive layer and the reflective mirror surface, exciting the intermediate phosphor layer, resulting in a light source device with high luminous efficiency, high color rendering index, and high color gamut.

[0013] Outer ring of the dam: The dam is constructed using a flexible dam adhesive and small-diameter needles, and an LED automatic dam construction machine is used to carry out the dam construction operation according to the programmed sequence.

[0014] Apply a protective layer; using high-transmittance, high-airtightness LED encapsulation silicone, after stirring and degassing, use a dispensing machine or spraying machine to evenly cover the phosphor layer with transparent LED encapsulation silicone, and then bake to form a high-airtightness protective layer with a certain thickness.

[0015] Furthermore, in the damming operation of the inner ring of the dam, specifically, a first inner dam ring is built at the edge of the mirror surface, the height of the first inner dam ring is 0.4mm, and it covers the substrate BT layer.

[0016] Furthermore, the height of the dam ring exceeds the arc of the line.

[0017] Furthermore, the step of applying the bottom protective adhesive involves using high-transmittance, high-temperature-resistant LED encapsulation silicone. After stirring and degassing, the transparent LED encapsulation silicone is evenly applied to the bottom of the substrate using a dispensing machine or a spraying machine. The adhesive completely encapsulates the light source bonding wire arc, ensuring that the bonding wire and the chip are within the same protective adhesive layer. The height of the entire lower protective adhesive layer does not exceed the inner circle of the dam, specifically ranging from 0.3 to 0.45 mm.

[0018] Furthermore, the LED encapsulation silicone is specifically low-refractive-index silicone.

[0019] Furthermore, the specific process parameters during the powder spraying process are as follows: atomization pressure range: 0.10~0.30Mpa; barrel pressure range: 0.02-0.025Mpa.

[0020] Furthermore, in the construction of the outer ring of the dam, specifically, a second outer ring of the dam is built immediately next to the first inner ring of the dam, and the height of the second outer ring of the dam ranges from 0.6 to 0.7 mm.

[0021] Furthermore, the second outer dam ring and the first inner dam ring form a stepped double dam effect with the inner layer being lower and the outer layer being higher.

[0022] Furthermore, the step involves applying a protective layer; using high-transmittance, high-airtightness LED encapsulation silicone, after stirring and degassing, the transparent LED encapsulation silicone is evenly coated onto the phosphor layer using a dispensing machine or spraying machine, and then baked to form a high-airtightness protective layer of a certain thickness, with the lower light-emitting area fully protected by the upper silicone layer.

[0023] The thickness range of the high airtightness protective adhesive layer is specifically 0.2-0.3 mm.

[0024] Furthermore, the LED encapsulation silicone is specifically a medium-fold silicone.

[0025] This invention, through its fabrication process, avoids the impact of high temperatures generated during LED chip operation on phosphor particles, and also prevents corrosion of the chip by chemical substances dissociated from the phosphor during long-term use. The second protective adhesive layer blocks moisture and other harmful gases from entering the light source, protecting the phosphor layer. This prevents moisture in the air and the high heat generated by the bottom chip during operation from affecting the phosphor particles. The inner and outer dam layers provide support and protection for the multi-layer colloidal structure of the light source.

[0026] In other words, the preparation process of this solution, through the proposed upper protective adhesive layer, can use vacuum coating technology to form a dense nano-coating protective film on the surface, further improving the weather resistance of the product.

[0027] In other words, through the above-described preparation process, a multi-layered, highly weather-resistant COB light source can be obtained. The lower layer uses high-transmittance, high-temperature-resistant silicone to ensure the reliability and temperature resistance of the light source. Layering and encapsulating the light source chip and phosphor significantly reduces the impact of the high heat generated by chip emission on the thermal quenching reaction of phosphor particles, allowing the phosphor particles to maintain a consistently high emission efficiency. Simultaneously, the upper protective layer uses high-transmittance, high-airtightness silicone, effectively solving the shortcomings of conventional COB light sources, such as soft silicone surfaces, high moisture and oxygen permeability, and poor resistance to sulfurization. This prevents moisture from entering the light source, ensuring the middle phosphor layer operates in a relatively dry and clean environment. This addresses the application pain points of fluoride phosphors or quantum dot phosphors being intolerant to temperature and moisture, resulting in a COB light source device with high luminous efficacy, high color rendering index, high color gamut, and high weather resistance.

[0028] Compared to existing multi-layer light source structures, this invention introduces a multi-layer structure into COB devices. By creating a stepped structure through two damming operations, the thickness of the first and second colloid layers is quantified, simplifying the manufacturing process. Simultaneously, it innovatively uses spray-applied phosphor to complete the central phosphor layer, avoiding the uneven distribution of adhesive powder in direct application and the delamination issues associated with using phosphor films. This results in more uniform light emission and a tighter internal connection of the light source. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the fabrication process of a high-efficiency, high-CRI, and high-weather-resistant multi-structure COB light source according to the present invention.

[0031] Figure 2 This is a top view schematic diagram of the product of the fabrication process of a high-efficiency, high-color-index, and high-weather-resistant multi-structure COB light source according to the present invention.

[0032] Figure 3 This is a cross-sectional schematic diagram of the product of the fabrication process of a high-efficiency, high-color-index, and high-weather-resistant multi-structure COB light source according to the present invention.

[0033] In the picture:

[0034] 1-COB substrate; 2-LED chip; 3-bonding wire; 4-first protective adhesive layer; 5-outer dam layer; 6-inner dam layer; 7-phosphor layer; 8-second protective adhesive layer;

[0035] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0036] To facilitate a clearer understanding of the objectives, technical solutions, and advantages of this invention, the invention will be further described below in conjunction with the accompanying drawings and specific embodiments. Those skilled in the art can easily understand other advantages and effects of this invention from the content disclosed in this specification.

[0037] This invention can also be implemented or applied through other different specific examples, and various details in this specification can also be modified and changed based on different viewpoints and applications without departing from the spirit of this invention.

[0038] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0039] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Secondly, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0040] The present invention will be further described below with reference to the accompanying drawings.

[0041] like Figures 1-3 As shown, this invention provides a fabrication process for a high-efficiency, high-CRI, and high-weather-resistant multi-structure COB light source, the process comprising the following steps:

[0042] S1. Die Bonding Process: Using an automatic LED die bonder, the blue LED chips are bonded to the COB substrate in the design order using die bonder adhesive. Then, the die bonder adhesive is thoroughly cured in a heated oven to complete the chip fixation.

[0043] S2. Wire bonding process: Using an automatic LED wire bonding machine, the LED blue light chip is connected to the electrodes through gold wires in the design sequence, and then connected to the positive and negative electrodes on the COB substrate to form a power supply path.

[0044] S3. Inner ring of the dam: The flexible damming adhesive and small-diameter needles are used, and the LED automatic damming machine is used to carry out the damming operation according to the program.

[0045] S4. Apply bottom protective adhesive: High light transmittance and high temperature resistance LED encapsulation silicone is used. After stirring and degassing, the transparent LED encapsulation silicone is evenly applied to the bottom of the substrate using a dispensing machine or spraying machine. The adhesive completely wraps the light source bonding wire arc, so that the bonding wire and the chip are in the same protective adhesive layer.

[0046] S5. Powder Spraying: High-efficiency fluoride phosphors or quantum dot phosphors with high excitation color gamut are used. The phosphors are adjusted and matched to obtain different color temperatures and color rendering index requirements. The phosphors are then dissolved in an organic diluent and stirred evenly. The phosphors are then evenly sprayed onto the bottom protective adhesive layer using a powder spraying device. The diluent in the original liquid phosphor layer is evaporated by heating and baking to solidify, forming the intermediate phosphor layer. After the adhesive is removed, it is atomized to spray the phosphor onto the light-emitting area. The bottom chip is powered on to excite blue light. The blue light is transmitted and reflected on the bottom adhesive layer and the reflective mirror surface, exciting the intermediate phosphor layer, resulting in a light source device with high luminous efficiency, high color rendering index, and high color gamut.

[0047] S6. Outer ring of the dam: The dam is constructed using a flexible dam adhesive and small-diameter needles, and an LED automatic dam construction machine is used to carry out the dam construction operation according to the programmed sequence.

[0048] S7. Apply the top protective adhesive: Use high-transmittance, high-airtightness LED encapsulation silicone. After stirring and degassing, use a dispensing machine or spraying machine to evenly cover the phosphor layer with transparent LED encapsulation silicone. Then bake to form a high-airtightness protective adhesive layer with a certain thickness.

[0049] In the damming operation of the inner ring of the dam, specifically, a first inner dam ring is built at the edge of the mirror surface. The height of the first inner dam ring is 0.4mm, and it covers the substrate BT layer.

[0050] The height of the dam ring exceeds the arc of the line.

[0051] The step of applying the bottom protective adhesive involves using high-transmittance, high-temperature-resistant LED encapsulation silicone. After stirring and degassing, the transparent LED encapsulation silicone is evenly applied to the bottom of the substrate using a dispensing machine or a spraying machine. The adhesive completely encapsulates the light source bonding wire arc, ensuring that the bonding wire and the chip are within the same protective adhesive layer. The height of the entire lower protective adhesive layer does not exceed the inner circle of the dam, specifically ranging from 0.3 to 0.45 mm.

[0052] The LED encapsulation silicone is specifically low-refractive-index silicone.

[0053] The specific process parameters during the powder spraying process are as follows: atomization pressure range: 0.10~0.30Mpa; barrel pressure range: 0.02-0.025Mpa.

[0054] In the construction of the outer ring of the dam, specifically, the second outer ring of the dam is built right next to the first inner ring of the dam. The height of the second outer ring of the dam is 0.6-0.7mm.

[0055] The second outer dam ring and the first inner dam ring form a stepped double dam effect with the inner layer being lower and the outer layer being higher.

[0056] The step described above involves applying a protective layer of adhesive. High-transmittance, high-airtightness LED encapsulation silicone is used. After stirring and degassing, the transparent LED encapsulation silicone is evenly applied to the phosphor layer using a dispensing machine or spraying machine. After baking, a high-airtightness protective layer of a certain thickness is formed, with the lower light-emitting area fully protected by the upper silicone layer.

[0057] The thickness range of the high airtightness protective adhesive layer is specifically 0.2-0.3 mm.

[0058] The LED encapsulation silicone is specifically a medium-fold silicone.

[0059] Specifically, in the embodiments of the present invention, the implementation process of the present invention is as follows:

[0060] Step 1: Die bonding; Using an automatic LED die bonding machine, the LED blue light chip 2 is bonded to the COB substrate 1 in the designed order using die bonding adhesive, and then the die bonding adhesive is completely cured in a heated oven, thus completing the chip fixation.

[0061] Step 2: Wire bonding; Using an automatic LED wire bonding machine, the LED blue light chip 2 is connected to the electrodes via gold wires in the designed sequence, and then connected to the positive and negative electrodes on the COB substrate 1 to form a power supply path.

[0062] Step 3: Inner damming ring; A highly flexible damming adhesive and a small-diameter needle are selected. An automatic LED damming machine is used to perform the damming operation according to the programmed sequence. The first inner damming ring (~6) is formed along the edge of the mirror surface, with a height of approximately 0.4mm, covering the BT layer of the substrate. The height of the damming ring should ideally slightly exceed the arc of the line.

[0063] Step 4: Apply bottom protective adhesive; Use high-transmittance, high-temperature-resistant LED encapsulation silicone (such as low-reflection silicone). After stirring and degassing, use a dispensing machine or spray gun to evenly cover the bottom of the substrate with transparent LED encapsulation silicone. The adhesive must completely encapsulate the light source bonding wire arc, ensuring the bonding wire and chip are on the same protective adhesive layer. This avoids the impact of sudden temperature changes during use on material reliability. The entire bottom protective adhesive layer should not exceed the inner ring of the dam, approximately 0.3-0.45mm.

[0064] Step 5: Powder Coating; High-efficiency fluoride phosphors or quantum dot phosphors with high excitation color gamut are selected. The proportions of the phosphors are adjusted to achieve different color temperatures and color rendering indexes. The phosphors are then dissolved in an organic diluent and stirred evenly. The phosphors are then uniformly sprayed onto the bottom protective adhesive layer using a powder coating machine. Heating and baking are then used to cure the phosphors, causing the diluent in the original liquid phosphor layer to evaporate and the phosphor colloid to solidify, forming the intermediate phosphor layer. The process parameters during powder coating are as follows: atomization pressure (0.10-0.30 MPa), after dispensing the adhesive, the adhesive is atomized to spray the phosphor onto the luminescent area; barrel pressure (0.02-0.025 MPa) helps circulate the phosphor adhesive inside the barrel and prevents sedimentation; appropriate spraying height, spraying speed, spraying interval, and atomization frequency are selected to ensure the phosphor layer adheres evenly and smoothly to the protective adhesive surface. When the bottom chip is powered on, it emits blue light. The blue light is transmitted and reflected through the bottom adhesive layer and the reflective mirror, exciting the middle phosphor layer, resulting in a light source device with high luminous efficiency, high color rendering index, and high color gamut.

[0065] Step 6: Enclosing the outer ring of the dam; Select a dam-enclosing adhesive with excellent flexibility and a small-diameter needle, and use an LED automatic dam-enclosing machine to perform the dam-enclosing operation according to the programmed sequence. The second outer dam ring (~5) is placed next to the first inner dam ring (~6), with a height of 0.6-0.7mm, forming a stepped shape with the first inner dam ring, creating a double dam effect.

[0066] Step 7: Apply the top protective adhesive; preferably use high-transmittance, high-airtightness LED encapsulation silicone (such as folded silicone). After stirring and degassing, use a dispensing machine or spraying machine to evenly cover the phosphor layer with transparent LED encapsulation silicone. After baking, a high-airtightness protective adhesive layer with a certain thickness (0.2-0.3mm) is formed. This adhesive layer has high hardness requirements, so that the lower light-emitting area is fully protected by the upper silicone layer, avoiding scratches and corrosion from moisture and water vapor in the air.

[0067] Ideally, different types of silicone have different properties: low-reflection silicone is soft and heat-resistant, but has poor airtightness; high-reflection silicone has the opposite properties; and medium-reflection silicone is between low-reflection and high-reflection silicone.

[0068] Furthermore, the present invention, in conjunction with the above-mentioned preparation process, also provides a special COB configuration to protect the phosphor luminescent particles. The upper protective layer isolates the phosphor particles from the corrosion caused by moisture and oxygen in the air. The middle phosphor particle layer is directly bonded to the adhesive surface by spraying powder to avoid delamination. The lower protective layer blocks the high heat emitted during chip excitation from affecting the luminescent particles. Thus, the high luminous efficiency of the phosphor luminescent particles is effectively maintained, achieving a high luminous efficiency, high color rendering index, and high color gamut optical product.

[0069] In other words, this solution also provides a multi-layer encapsulation structure that can reduce the impact of air humidity and the high heat generated during the operation of the bottom chip on the phosphor particles. To achieve the above objective, this invention proposes a COB structure, which includes: a bottom substrate, a light-emitting chip, bonding wires, a bottom protective adhesive layer, a middle phosphor layer, an upper protective adhesive layer, and a double dam layer. The substrate serves as the supporting foundation for the entire light source, and the light-emitting chip is the core of the light source emission. The bottom protective adhesive layer separates the phosphor particles from the chip, preventing the high temperature generated during chip operation from affecting the phosphor particles and also preventing the chemical substances released from the phosphor during long-term use from corroding the chip. The middle phosphor layer is the core of the light source excitation. The upper protective adhesive layer blocks air humidity and other harmful gases from entering the interior of the light source, protecting the phosphor layer. The double dam layer provides support and protection for the multi-layer colloidal structure of the light source.

[0070] Specifically, a multi-layer encapsulation structure is provided to reduce the impact of air humidity and the high heat generated during the operation of the bottom chip on phosphor particles. To achieve the above objective, this invention proposes a COB structure, which includes: a bottom substrate, a light-emitting chip, bonding wires 3, a bottom protective adhesive layer, a middle phosphor layer 7, an upper protective adhesive layer, and a double dam layer. The substrate serves as the supporting foundation for the entire light source, and the light-emitting chip is the core of the light source emission. The bottom protective adhesive layer separates the phosphor particles from the chip, preventing the high temperature generated during chip operation from affecting the phosphor particles and also preventing the chemical substances released from the phosphor during long-term use from corroding the chip. The middle phosphor layer 7 is the excitation core of the light source. The upper protective adhesive layer blocks air humidity and other harmful gases from entering the interior of the light source, protecting the phosphor layer 7. The double dam layer provides support and protection for the multi-layer colloidal structure of the light source.

[0071] During use, the chip generates blue light when powered on, which excites the central phosphor layer 7. The heat generated by the chip's light emission has little impact on the central phosphor layer 7, which can greatly reduce the thermal quenching effect of the phosphor and ensure that the phosphor particles can always maintain a high excitation efficiency, thus improving the luminous efficiency. At the same time, the upper protective adhesive layer blocks air, slows down the corrosion and failure of the phosphor particles, and can significantly improve the lifespan of the light source.

[0072] In other words, a new COB structure model is provided, which can effectively protect the high-efficiency phosphor inside the device, reduce the impact of high temperature and high humidity on phosphor particles, and make the light source have higher reliability.

[0073] The aforementioned multi-layered, high-weather-resistant COB light source is a packaged device, comprising at least an LED chip 2, a COB substrate 1, bonding wires 3, a bottom protective adhesive layer (first protective adhesive layer 4), a middle phosphor layer 7, an upper protective adhesive layer (second protective adhesive layer 8), an outer dam layer 5, and an inner dam layer 6. A top view of the aforementioned multi-layered, high-weather-resistant COB light source is shown below. Figure 1 As shown in the cross-sectional view Figure 2 As shown.

[0074] The high weather-resistant COB light source comprises at least one blue LED chip. The LED chip 2 generally includes a P-electrode, an N-electrode, and a substrate. Preferably, the epitaxial layer is doped gallium nitride, and the substrate is sapphire. The COB substrate 1 generally includes positive and negative electrode pads, a mirror reflection area, and a base. The bonding wires 3 are generally metal bonding wires, serving to connect circuits. The bottom protective adhesive layer is generally a silicone material with high light transmittance and high temperature resistance. The middle phosphor layer 7 is generally a light-emitting layer composed of fluorescent particles that can absorb energy and then emit visible light after energy conversion. Preferred fluorescent particles in this invention are fluoride phosphors or quantum dot phosphors with high excitation efficiency, which are directly coated onto the protective adhesive layer using a spraying process to prevent direct contact between the phosphor layer 7 and the bottom chip.

[0075] The upper protective adhesive layer is generally a silicone material with high airtightness and high light transmittance. The inner and outer dam rings are generally a single-component heat-cured silicone rubber material.

[0076] Preferably, the first layer of the dam ring, i.e., the inner dam ring, has a dam height of approximately 0.4 at the edge of the mirror, slightly exceeding the arc of the line; the second layer of the dam ring, i.e., the outer dam ring, has a dam height of approximately 0.7 at the edge of the BT, serving as the overall support; the phosphor luminescent layer is covered with KSF phosphor as the main powder using a fluorescent film or powder spraying process; the encapsulating adhesive protection process can be applied by dispensing or applying a surface coating process to protect the outside of the adhesive; the first layer of dispensing or spraying protection (i.e., the first protective adhesive layer 4) uses low- or medium-fold silicone, preferably slightly exceeding the arc of the line.

[0077] This invention utilizes a COB substrate 1 and multiple LED chips 2 disposed on the upper surface of the COB substrate 1. The LED chips 2 are electrically connected to the COB substrate 1 via bonding wires 3. A phosphor layer 7 is disposed on the upper side of the LED chips 2. The phosphor layer 7 and the LED chips 2 are separated by a first protective adhesive layer 4. A second protective adhesive layer 8 is also disposed on the upper side of the phosphor layer 7. An inner dam layer 6 and an outer dam layer 5 are respectively disposed around the first protective adhesive layer 4. On the one hand, this can prevent the high temperature generated during the operation of the LED chips 2 from affecting the phosphor particles. On the other hand, it can also prevent the chemical substances dissociated from the phosphor during long-term use of the light source from corroding the chip. The second protective adhesive layer 8 blocks moisture and other harmful gases in the air from entering the interior of the light source, protecting the phosphor layer 7. This avoids the impact of moisture in the air and the high heat generated during the operation of the bottom chip on the phosphor particles. The inner dam layer 6 and the outer dam layer 5 provide support and protection for the multi-layer colloidal structure of the light source.

[0078] This invention, through its fabrication process, avoids the impact of high temperatures generated during LED chip operation on phosphor particles, and also prevents corrosion of the chip by chemical substances dissociated from the phosphor during long-term use. The second protective adhesive layer blocks moisture and other harmful gases from entering the light source, protecting the phosphor layer. This prevents moisture in the air and the high heat generated by the bottom chip during operation from affecting the phosphor particles. The inner and outer dam layers provide support and protection for the multi-layer colloidal structure of the light source.

[0079] In other words, the preparation process of this solution, through the proposed upper protective adhesive layer, can use vacuum coating process to form a dense nano-coating protective film on the surface, further improving the weather resistance of the product. The middle phosphor layer is preferably prepared by powder spraying process, but it can also be completed by applying a phosphor film.

[0080] In other words, through the above-described preparation process, a multi-layered, highly weather-resistant COB light source can be obtained. The lower layer uses high-transmittance, high-temperature-resistant silicone to ensure the reliability and temperature resistance of the light source. Layering and encapsulating the light source chip and phosphor significantly reduces the impact of the high heat generated by chip emission on the thermal quenching reaction of phosphor particles, allowing the phosphor particles to maintain a consistently high emission efficiency. Simultaneously, the upper protective layer uses high-transmittance, high-airtightness silicone, effectively solving the shortcomings of conventional COB light sources, such as soft silicone surfaces, high moisture and oxygen permeability, and poor resistance to sulfurization. This prevents moisture from entering the light source, ensuring the middle phosphor layer operates in a relatively dry and clean environment. This addresses the application pain points of fluoride phosphors or quantum dot phosphors being intolerant to temperature and moisture, resulting in a COB light source device with high luminous efficacy, high color rendering index, high color gamut, and high weather resistance.

[0081] Compared to existing multi-layer light source structures, this invention introduces a multi-layer structure into COB devices. By creating a stepped structure through two damming operations, the thickness of the first and second colloid layers is quantified, simplifying the manufacturing process. Simultaneously, it innovatively uses spray-applied phosphor to complete the central phosphor layer, avoiding the uneven distribution of adhesive powder in direct application and the delamination issues associated with using phosphor films. This results in more uniform light emission and a tighter internal connection of the light source.

[0082] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are 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 modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A fabrication process for a high-efficiency, high-CRI, and high-weather-resistant multi-structure COB light source, characterized in that... The process specifically includes the following steps: Die bonding process: Using an automatic LED die bonding machine, the blue LED chips are bonded to the COB substrate in the design order using die bonding adhesive. Then, the die bonding adhesive is thoroughly cured in a heated oven to complete the chip fixation. Wire bonding process: Using an automatic LED wire bonding machine, the LED blue light chip is connected to the electrodes via gold wires in the design sequence, and then connected to the positive and negative electrodes on the COB substrate to form a power path; Inner ring of the dam: The flexible dam-building adhesive and small-diameter needles are used, and the LED automatic dam-building machine is used to carry out the dam-building operation according to the programmed procedure; Bottom protective adhesive: High-transmittance, high-temperature-resistant LED encapsulation silicone is used. After stirring and degassing, the transparent LED encapsulation silicone is evenly applied to the bottom of the substrate using a dispensing machine or spraying machine. The adhesive completely wraps the light source bonding wire arc, so that the bonding wire and the chip are in the same protective adhesive layer. The height of the entire lower protective adhesive layer does not exceed the inner circle of the dam, and the specific height range is 0.3-0.45mm. The LED encapsulation silicone is specifically low-reflection silicone. Powder spraying: High-efficiency fluoride phosphors or quantum dot phosphors with high excitation color gamut are used, and the phosphors are adjusted and matched to obtain different color temperatures and color rendering index requirements. The phosphors are then dissolved in an organic diluent and stirred evenly. The phosphors are then evenly sprayed onto the bottom protective adhesive layer using a powder spraying device. After heating and curing, the diluent in the original liquid phosphor layer evaporates, and the phosphor colloid solidifies to form an intermediate phosphor layer. After the adhesive is removed, it is atomized and sprayed onto the light-emitting area. The bottom chip is powered on to excite blue light, which is transmitted and reflected on the bottom adhesive layer and the reflective mirror surface, exciting the intermediate phosphor layer, resulting in a light source device with high luminous efficiency, high color rendering index, and high color gamut. Outer ring of the dam: The dam is constructed using a flexible dam adhesive and small-diameter needles, and an LED automatic dam construction machine is used to carry out the dam construction operation according to the programmed procedure; the second outer dam ring and the first inner dam ring form a stepped double dam effect with the inner ring being lower and the outer ring being higher. Apply a top protective adhesive layer; using high-transmittance, high-airtightness LED encapsulation silicone, after stirring and degassing, the transparent LED encapsulation silicone is evenly coated onto the phosphor layer using a dispensing machine or spraying machine, and then baked to form a high-airtightness protective adhesive layer of a certain thickness, with the lower light-emitting area fully protected by the top silicone layer; the thickness range of the high-airtightness protective adhesive layer is specifically 0.2-0.3mm, and the LED encapsulation silicone is specifically a medium-fold silicone.

2. The fabrication process of a high-efficiency, high-CRI, and high-weather-resistant multi-structure COB light source according to claim 1, characterized in that... In the damming operation of the inner ring of the dam, specifically, a first inner dam ring is built at the edge of the mirror surface. The height of the first inner dam ring is 0.4mm, and it covers the substrate BT layer.

3. The fabrication process of a high-efficiency, high-CRI, and high-weather-resistant multi-structure COB light source according to claim 2, characterized in that... The height of the dam ring exceeds the arc of the line.

4. The fabrication process of a high-efficiency, high-CRI, and high-weather-resistant multi-structure COB light source according to claim 1, characterized in that... The specific process parameters during the powder spraying process are as follows: atomization pressure range: 0.10~0.30Mpa; barrel pressure range: 0.02-0.025Mpa.

5. The fabrication process of a high-efficiency, high-CRI, and high-weather-resistant multi-structure COB light source according to claim 1, characterized in that... In the construction of the outer ring of the dam, specifically, the second outer ring of the dam is built right next to the first inner ring of the dam. The height of the second outer ring of the dam is 0.6-0.7mm.

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