Light emitting unit and method of manufacturing the same

Abstract

The present disclosure provides a light-emitting unit and a manufacturing method thereof. The light-emitting unit comprises a circuit board, a light-emitting device and a protective layer; the light-emitting device is located on the circuit board and electrically connected with the circuit board; the protective layer covers the surface and the sidewall of the light-emitting device; the protective layer is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of an epoxy resin, a curing agent, a modifier, a functional filler, an accelerator, a leveling agent and a defoaming agent.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a light-emitting unit and a method for manufacturing the same. Background Technology

[0002] Light-emitting diodes (LEDs) are widely used in the manufacture of light-emitting devices due to their advantages such as energy saving, environmental protection, and long lifespan. These devices are then packaged into light-emitting units.

[0003] The related technology provides a light-emitting unit, which includes a circuit board and a light-emitting device, the light-emitting device being located on the circuit board and electrically connected to the circuit board.

[0004] However, the light-emitting unit provided by the related technology has low reliability because the light-emitting device is exposed to the external environment. Water vapor (H2O), oxygen (O2), sulfides (such as H2S), halides and other substances in the external environment will enter the interior of the light-emitting device, causing oxidation reaction in the internal structure of the light-emitting device. Summary of the Invention

[0005] This disclosure provides a backlight module, a light-emitting unit, and a method for manufacturing the same, which can improve the reliability of the light-emitting unit. The technical solution is as follows: On the one hand, a light-emitting unit is provided, the light-emitting unit comprising: Circuit board, light-emitting device, and protective layer; The light-emitting device is located on the circuit board, the light-emitting device is electrically connected to the circuit board (101), and the protective layer covers the surface and sidewalls of the light-emitting device; The protective layer is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent and defoamer.

[0006] Optionally, the epoxy resin is a bisphenol A type epoxy resin, the curing agent is methylhexahydrophthalic anhydride, the modifier is terminal epoxy-terminated polydimethylsiloxane, the functional filler is organically modified nano-montmorillonite, the accelerator is benzyl dimethylamine, the leveling agent is polyether-modified dimethylsiloxane, and the defoamer is a defoaming polysiloxane solution.

[0007] Optionally, the epoxy resin is 95-105 parts by weight, the curing agent is 30-50 parts by weight, the modifier is 5-15 parts by weight, the functional filler is 3-8 parts by weight, the accelerator is 0.5-2 parts by weight, the leveling agent is 0.3-1 part by weight, and the defoamer is 0.2-0.5 parts by weight.

[0008] Optionally, the thickness of the protective layer is 10~30μm.

[0009] On the other hand, a method for manufacturing a light-emitting unit is provided, the method comprising: A light-emitting device is mounted on a circuit board, and the light-emitting device is electrically connected to the circuit board. A protective layer is formed, which covers the surface and sidewalls of the light-emitting device. The protective layer is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent and defoamer.

[0010] Optionally, a modified polycyclic resin coating may be prepared; The surfaces of the light-emitting device and the circuit board are cleaned. The modified polycyclic resin coating is applied to the surface and sidewalls of the light-emitting device; The modified polycyclic resin coating is cured to form the protective layer.

[0011] Optionally, the epoxy resin is a bisphenol A type epoxy resin, the curing agent is methylhexahydrophthalic anhydride, the modifier is terminal epoxy-terminated polydimethylsiloxane, the functional filler is organically modified nano-montmorillonite, the accelerator is benzyl dimethylamine, the leveling agent is polyether-modified dimethylsiloxane, and the defoamer is a polysiloxane solution.

[0012] Optionally, the preparation of the modified polycyclic resin coating includes: Add 95-105 parts by weight of the bisphenol A type epoxy resin and 5-15 parts by weight of the terminal epoxy polydimethylsiloxane to a reaction vessel, and stir for 28-32 minutes at a reaction temperature of 75-85°C. The organically modified nano-montmorillonite in a mass ratio of 3 to 8 parts was added to the reaction vessel and ultrasonically treated for 18 to 22 minutes under an ultrasonic power of 250 to 300 W. The reaction temperature is lowered to 55-65°C, and 30-50 parts by mass of the methylhexahydrophthalic anhydride and 0.5-2 parts by mass of the benzyl dimethylamine are added to the reaction vessel and stirred for 13-17 minutes at a speed of 450-550 rpm. Add 0.3 to 1 part by weight of the polyether-modified dimethylsiloxane and 0.2 to 0.5 parts by weight of the polysiloxane solution to the reactor, and stir for 7 to 13 minutes at a speed of 150 to 250 rpm.

[0013] Optionally, the modified polycyclic resin coating is applied to the surface and sidewalls of the light-emitting device, comprising: The modified polycyclic resin coating is applied to the surface and sidewalls of the light-emitting device using a precision dispensing machine. The thickness of the modified polycyclic resin coating is 10~30μm. Apply the modified polycyclic resin to the connection between the sidewall of the light-emitting device and the circuit board.

[0014] Optionally, the light-emitting device coated with the modified polycyclic resin coating is left to stand at room temperature for 10 to 20 minutes; The modified polycyclic resin coating, after being allowed to stand, is heated at a temperature of 60-80°C for 0.9-1.1 hours. The modified polycyclic resin coating, after heating, is cured at a temperature of 120~140℃ for 2~3 hours to form the protective layer.

[0015] The beneficial effects of the technical solutions provided in this disclosure are: In this embodiment, the light-emitting device is located on a circuit board and electrically connected to the circuit board, thus forming the basic structure of the light-emitting unit. Based on this, a protective layer covers the surface and sidewalls of the light-emitting device, isolating it from the external environment and preventing moisture, oxygen, sulfides, halides, etc., from entering the device, thereby improving the reliability of the light-emitting unit. The protective layer is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent, and defoamer. Epoxy resin is the core component of the modified polycyclic resin, determining its basic chemical structure and physical properties, and providing the basic framework for the protective layer. The curing agent can promote the cross-linking reaction of the chemical functional groups in the epoxy resin, effectively improving the production efficiency of the protective layer. The modifier can improve the epoxy resin, thereby enhancing the barrier properties of the protective layer. The functional filler can increase the hardness of the protective layer. The protective layer is made of abrasion-resistant materials and has a smooth surface. Accelerators can speed up the chemical reaction between the curing agent and epoxy resin, thereby further improving the production efficiency of the protective layer. Leveling agents can make the protective layer form a smooth surface during the production process, reduce defects in the protective layer, improve the barrier ability of the protective layer, and the smooth surface can also meet the appearance requirements of the light-emitting unit. Defoamers can prevent the generation of bubbles during the production of the protective layer, thereby improving the density of the protective layer and better preventing water vapor, oxygen, sulfides, halides and other substances in the external environment from entering the light-emitting device, thus improving the reliability of the light-emitting unit. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this disclosure, 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 this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a structural diagram of a light-emitting unit provided in an embodiment of this disclosure; Figure 2 This is a flowchart of the method for fabricating a light-emitting unit provided in the embodiments of this disclosure; Figure 3 This is a flowchart of the method for fabricating a light-emitting unit provided in the embodiments of this disclosure.

[0018] The attached figures are labeled as follows: 101: Circuit board; 102: Light-emitting device; 103: Protective layer; 201: Support; 202: Reflective layer; 203: Light-emitting diode chip; 204: Wire; 205: Phosphor layer; 210: Support cup; 211: Support pin. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this disclosure clearer, the embodiments of this disclosure will be described in further detail below with reference to the accompanying drawings.

[0020] Figure 1 This is a structural diagram of a light-emitting unit provided in an embodiment of this disclosure. See also... Figure 1 The light-emitting unit includes: a circuit board 101, a light-emitting device 102, and a protective layer 103.

[0021] The light-emitting device 102 is located on the circuit board 101 and is electrically connected to the circuit board 101. The protective layer 103 covers the surface and sidewalls of the light-emitting device 102.

[0022] The protective layer 103 is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent and defoamer.

[0023] In this embodiment, the light-emitting device is located on a circuit board and electrically connected to the circuit board, thus forming the basic structure of the light-emitting unit. Based on this, a protective layer covers the surface and sidewalls of the light-emitting device, isolating it from the external environment and preventing moisture, oxygen, sulfides, halides, etc., from entering the device, thereby improving the reliability of the light-emitting unit. The protective layer is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent, and defoamer. Epoxy resin is the core component of the modified polycyclic resin, determining its basic chemical structure and physical properties, and providing the basic framework for the protective layer. The curing agent can promote the cross-linking reaction of the chemical functional groups in the epoxy resin, effectively improving the production efficiency of the protective layer. The modifier can improve the epoxy resin, thereby enhancing the barrier properties of the protective layer. The functional filler can increase the hardness of the protective layer. The protective layer is made of abrasion-resistant materials and has a smooth surface. Accelerators can speed up the chemical reaction between the curing agent and epoxy resin, thereby further improving the production efficiency of the protective layer. Leveling agents can make the protective layer form a smooth surface during the production process, reduce defects in the protective layer, improve the barrier ability of the protective layer, and the smooth surface can also meet the appearance requirements of the light-emitting unit. Defoamers can prevent the generation of bubbles during the production of the protective layer, thereby improving the density of the protective layer and better preventing water vapor, oxygen, sulfides, halides and other substances in the external environment from entering the light-emitting device, thus improving the reliability of the light-emitting unit.

[0024] In this embodiment, the epoxy resin is bisphenol A type epoxy resin, the curing agent is methylhexahydrophthalic anhydride, the modifier is terminal epoxy-terminated polydimethylsiloxane, the functional filler is organically modified nano-montmorillonite, the accelerator is benzyl dimethylamine, the leveling agent is polyether-modified dimethylsiloxane, and the defoamer is a defoaming polysiloxane solution.

[0025] In this implementation, the epoxy resin is a bisphenol A type epoxy resin. Bisphenol A type epoxy resin has good toughness, allowing the protective layer to maintain a certain degree of deformation capacity and preventing cracks. Simultaneously, bisphenol A type epoxy resin also has good adhesion, ensuring the protective layer does not easily detach, thereby improving the reliability of the light-emitting unit. The curing agent is methylhexahydrophthalic anhydride, which has high thermal stability and can rapidly promote the curing reaction of the protective layer even at high temperatures. The modifier is terminal epoxy-based polydimethylsiloxane. By introducing flexible Si-O-Si segments, the toughness of the epoxy resin can be significantly improved. These flexible segments can effectively disperse stress and prevent crack propagation, thereby improving the barrier properties of the protective layer. The functional filler is organically modified nano-montmorillonite. The layered structure of nano-montmorillonite can form a physical barrier, effectively preventing water vapor, oxygen, sulfides, halides, etc., from entering the light-emitting device from the external environment, thereby improving the barrier performance of the protective layer. The accelerator, benzyl dimethylamine, accelerates the chemical reaction between the curing agent and epoxy resin, thereby further improving the efficiency of protective layer production. The leveling agent, polyether-modified dimethylsiloxane, reduces the surface tension of bisphenol A epoxy resin, filling uneven areas in the protective layer to form a smooth surface, reducing defects and improving its barrier properties. The defoamer, a defoaming polysiloxane solution, prevents bubble formation, thus improving the density of the protective layer.

[0026] In other embodiments, the epoxy resin may also be other materials, such as bisphenol F type epoxy resin.

[0027] In other embodiments, the curing agent may also be other materials, such as phenolic resin.

[0028] In other embodiments, the modifier may also be other materials, such as epoxy-based silicone oil.

[0029] In other embodiments, the functional filler may also be other materials, such as nanoclay.

[0030] In other embodiments, the promoter may also be other materials, such as organophosphorus compounds.

[0031] In other embodiments, the leveling agent may also be other materials, such as polyether-modified silicone oil.

[0032] In other embodiments, the defoamer may also be other materials, such as reactive defoamers.

[0033] In the embodiments of this disclosure, the epoxy resin is 95-105 parts by weight, the curing agent is 30-50 parts by weight, the modifier is 5-15 parts by weight, the functional filler is 3-8 parts by weight, the accelerator is 0.5-2 parts by weight, the leveling agent is 0.3-1 part by weight, and the defoamer is 0.2-0.5 parts by weight.

[0034] In this implementation, the epoxy resin comprises 95-105 parts by mass, with a lower limit of 95 parts to ensure the formation of a continuous resin phase, fully coating the filler and forming an effective bond with the substrate. The upper limit of 105 parts by mass avoids excessive resin leading to increased curing shrinkage and high viscosity, thus achieving rational utilization of raw materials while ensuring performance. The curing agent comprises 30-50 parts by mass, with a lower limit of 30 parts to ensure sufficient reaction of the epoxy groups and avoid incomplete curing. The upper limit of 50 parts by mass prevents excessive anhydride from causing excessive crosslinking density and increased brittleness. The modifier comprises 5-15 parts by mass, with a lower limit of 5 parts to impart basic toughness to the coating and reduce internal stress. The upper limit of 15 parts by mass significantly improves the toughness and flexibility of the protective layer, preventing crack propagation while avoiding strength reduction due to excessive siloxane segments. The functional filler comprises 3 to 8 parts by weight, with a lower limit of 3 parts. It forms a preliminary layered barrier structure, enhancing hardness, strength, and barrier properties. An upper limit of 8 parts avoids dispersion difficulties and viscosity spikes caused by excessive filler. The accelerator comprises 0.5 to 2 parts by weight, with a lower limit of 0.5 parts. It effectively reduces the activation energy of the curing reaction, significantly accelerating the reaction rate. An upper limit of 2 parts avoids excessively short gel times. The leveling agent comprises 0.3 to 1 part by weight, with a lower limit of 0.3 parts. It reduces surface tension, minimizes pinholes, and significantly improves leveling properties. An upper limit of 1 part avoids decreased interlayer adhesion due to excessive leveling. The defoamer is used in quantities of 0.2 to 0.5 parts by weight, with a lower limit of 0.2 parts by weight. This helps to suppress the generation of bubbles during stirring and curing, ensuring the density of the coating. The upper limit of the defoamer is 0.5 parts by weight, which helps to avoid surface defects caused by excessive amounts.

[0035] For example, the epoxy resin is 97-103 parts by weight, the curing agent is 32-48 parts by weight, the modifier is 7-13 parts by weight, the functional filler is 5-6 parts by weight, the accelerator is 0.7-1.8 parts by weight, the leveling agent is 0.5-0.8 parts by weight, and the defoamer is 0.3-0.4 parts by weight.

[0036] For example, the epoxy resin has 98 parts by weight, the curing agent has 33 parts by weight, the modifier has 9 parts by weight, the functional filler has 5 parts by weight, the accelerator has 1 part by weight, the leveling agent has 0.5 parts by weight, and the defoamer has 0.3 parts by weight.

[0037] For example, the epoxy resin is 100 parts by weight, the curing agent is 40 parts by weight, the modifier is 10 parts by weight, the functional filler is 5.5 parts by weight, the accelerator is 1.5 parts by weight, the leveling agent is 0.7 parts by weight, and the defoamer is 0.4 parts by weight.

[0038] In this embodiment of the disclosure, the thickness of the protective layer 103 can be 10~30μm.

[0039] In this implementation, the thickness of the protective layer 103 is at least 10 μm. Sufficient thickness allows the protective layer to have good barrier properties, which can better prevent water vapor, oxygen, sulfides, halides and other substances in the external environment from entering the light-emitting device and improve the reliability of the light-emitting unit. At the same time, the upper limit of the thickness is 30 μm, which avoids cracking problems caused by excessive thickness of the protective layer and further improves the reliability of the light-emitting unit.

[0040] For example, the thickness of the protective layer 103 is 15 μm or 20 μm.

[0041] In this embodiment of the disclosure, the circuit board 101 can be a flexible printed circuit (FPC).

[0042] In this embodiment of the disclosure, the light-emitting device 102 includes a support 201, a reflective layer 202, a light-emitting diode chip 203, a wire 204, and a phosphor layer 205.

[0043] The bracket 201 includes a bracket cup 210 and a bracket pin 211. The bracket cup 210 has a bowl-shaped structure and is mounted on the circuit board 101. The bracket pin 211 is embedded in the bottom of the bracket cup 210 and is electrically connected to the circuit board 101.

[0044] The light-emitting diode chip 203 is located on the bracket 201. The reflective layer 202 covers the bottom of the bracket cup 210 around the light-emitting diode chip 203. The light-emitting diode chip 203 is electrically connected to the bracket pin 211 through the wire 204. The phosphor layer 205 is located inside the bracket cup 210 and covers the light-emitting diode chip 203.

[0045] In this embodiment of the disclosure, the support 201 may be made of materials such as silicone or epoxy resin.

[0046] For example, the material of the bracket 201 is silicone.

[0047] In this embodiment, the reflective layer 202 may be made of materials such as nickel, silver, or gold.

[0048] For example, the reflective layer 202 can be made of silver.

[0049] In this embodiment of the disclosure, the conductor 204 can be a metal conductor such as silver, gold, copper or an alloy.

[0050] For example, conductor 204 is a copper metal conductor.

[0051] In this embodiment of the disclosure, the conductor 204 can be a J-shaped arc.

[0052] In other embodiments, the conductor 204 may also be other arcs, such as M-shaped arcs.

[0053] In this embodiment, the phosphor layer 205 is a mixture of phosphor and adhesive.

[0054] In this embodiment of the present disclosure, the top view of the support bowl 210 is circular.

[0055] In other embodiments, the top view of the support bowl 210 can also be other shapes, such as rectangles.

[0056] Figure 2 This is a flowchart of a method for fabricating a light-emitting unit according to an embodiment of this disclosure. See also... Figure 2 The method includes the following steps: S11. The light-emitting device is placed on the circuit board, and the light-emitting device is electrically connected to the circuit board.

[0057] S12. Fabricate a protective layer, the protective layer covering the surface and sidewalls of the light-emitting device, the protective layer being a modified polycyclic resin layer, the modified polycyclic resin layer being a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent and defoamer.

[0058] In this embodiment, the light-emitting device is located on a circuit board and electrically connected to the circuit board, thus forming the basic structure of the light-emitting unit. Based on this, a protective layer covers the surface and sidewalls of the light-emitting device, isolating it from the external environment and preventing moisture, oxygen, sulfides, halides, etc., from entering the device, thereby improving the reliability of the light-emitting unit. The protective layer is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent, and defoamer. Epoxy resin is the core component of the modified polycyclic resin, determining its basic chemical structure and physical properties, and providing the basic framework for the protective layer. The curing agent can promote the cross-linking reaction of the chemical functional groups in the epoxy resin, effectively improving the production efficiency of the protective layer. The modifier can improve the epoxy resin, thereby enhancing the barrier properties of the protective layer. The functional filler can increase the hardness of the protective layer. The protective layer is made of abrasion-resistant materials and has a smooth surface. Accelerators can speed up the chemical reaction between the curing agent and epoxy resin, thereby further improving the production efficiency of the protective layer. Leveling agents can make the protective layer form a smooth surface during the production process, reduce defects in the protective layer, improve the barrier ability of the protective layer, and the smooth surface can also meet the appearance requirements of the light-emitting unit. Defoamers can prevent the generation of bubbles during the production of the protective layer, thereby improving the density of the protective layer and better preventing water vapor, oxygen, sulfides, halides and other substances in the external environment from entering the light-emitting device, thus improving the reliability of the light-emitting unit.

[0059] Figure 3 This is a flowchart of a method for fabricating a light-emitting unit according to an embodiment of this disclosure. See also... Figure 3 The method includes the following steps: S21. Fabricate light-emitting devices.

[0060] For example, step S21 may include: The first step is to provide a support, which includes a support cup and support pins. The support cup has a bowl-shaped structure. A reflective layer is electroplated on the bottom of the support cup.

[0061] In this embodiment of the disclosure, the bottom of the support bowl is embedded with support pins.

[0062] In this embodiment of the disclosure, the support can be made of materials such as silicone or epoxy resin.

[0063] For example, the support is made of silicone.

[0064] In this embodiment of the disclosure, the reflective layer may be made of materials such as nickel, silver, or gold.

[0065] For example, the reflective layer can be made of silver.

[0066] In this embodiment of the present disclosure, the top view of the support bowl is circular.

[0067] In other embodiments, the top view of the support bowl cup can also be other shapes, such as rectangles.

[0068] The second step is to fix the LED chip onto the bracket.

[0069] In this embodiment of the disclosure, the light-emitting diode chip is located on a support, and a reflective layer covers the bottom of the support cup surrounding the light-emitting diode chip.

[0070] The third step is to electrically connect the LED chip to the bracket pins using wires.

[0071] In this embodiment of the disclosure, the wire can be a metal wire such as silver, gold, copper or alloy.

[0072] For example, the wire is a copper metal wire.

[0073] In this embodiment of the disclosure, the conductor can be a J-shaped arc.

[0074] In other embodiments, the conductor may also be other arcs, such as M-shaped arcs.

[0075] The fourth step is to apply fluorescent adhesive to the inside of the support bowl.

[0076] In this embodiment of the disclosure, the fluorescent adhesive is a mixture of fluorescent powder and adhesive.

[0077] The fifth step is to bake and cure the fluorescent adhesive to form a fluorescent powder layer.

[0078] S22. The light-emitting device is placed on the circuit board, and the light-emitting device is electrically connected to the circuit board through a conductive material.

[0079] For example, step S22 may include: The first step is to place an appropriate amount of conductive material on the circuit board.

[0080] In the embodiments disclosed herein, the conductive material may be silver paste, solder paste, etc.

[0081] For example, the conductive material can be solder paste.

[0082] In this embodiment of the disclosure, an appropriate amount of conductive material is placed on the circuit board by printing or dispensing / spraying the valve body.

[0083] For example, an appropriate amount of conductive material is placed on a circuit board by printing.

[0084] The second step is to place the light-emitting unit on the circuit board.

[0085] In this embodiment of the disclosure, the light-emitting unit is placed on the circuit board by a pick-and-place machine or a die bonder.

[0086] For example, the light-emitting unit is precisely placed on the circuit board using a pick-and-place machine.

[0087] The third step involves high-temperature curing to form an electrical pathway.

[0088] In this embodiment, the fixed light-emitting unit and circuit board are subjected to high-temperature curing treatment, so that the conductive material is cured at high temperature to form electrical conductivity, providing a stable foundation for subsequent reflow soldering.

[0089] The fourth step is to perform reflow soldering.

[0090] In this embodiment of the disclosure, the mounted light-emitting unit is soldered to the circuit board using a conductive material, so that the support pins of the light-emitting unit are electrically connected to the circuit board.

[0091] S23. Prepare modified polycyclic resin coatings.

[0092] For example, step S23 may include: The first step involves adding 95-105 parts by weight of bisphenol A type epoxy resin and 5-15 parts by weight of terminal epoxy polydimethylsiloxane to a reaction vessel and stirring for 28-32 minutes at a reaction temperature of 75-85°C.

[0093] In this implementation, the mass fraction of bisphenol A epoxy resin is 95-105 parts, with a lower limit of 95 parts to ensure the formation of a continuous resin phase, fully coating the filler and forming an effective bond with the substrate. The upper limit of 105 parts avoids problems such as increased curing shrinkage and high viscosity caused by excessive resin, thus achieving rational utilization of raw materials while ensuring performance. The mass fraction of terminal epoxy-based polydimethylsiloxane is 5-15 parts, with a lower limit of 5 parts to impart basic toughness to the coating and reduce internal stress. The upper limit of 15 parts significantly improves the toughness and flexibility of the protective layer, preventing crack propagation while avoiding strength reduction due to excessive siloxane segments. Stirring at a reaction temperature of 75-85℃ for 28-32 minutes ensures uniform dispersion of the modifier.

[0094] For example, 97-103 parts by weight of bisphenol A type epoxy resin and 7-13 parts by weight of terminal epoxy group polydimethylsiloxane are added to a reaction vessel and stirred for 29-31 minutes at a reaction temperature of 77-83°C. For example, 100 parts by weight of bisphenol A type epoxy resin and 10 parts by weight of terminal epoxy group polydimethylsiloxane are added to a reaction vessel and stirred for 30 minutes at a reaction temperature of 80°C. The second step involves adding 3 to 8 parts by weight of the organically modified nano-montmorillonite to the reactor and subjecting it to ultrasonic treatment for 18 to 22 minutes at an ultrasonic power of 250 to 300 W.

[0095] In this implementation, the mass fraction of organically modified nano-montmorillonite is 3-8 parts, with a lower limit of 3 parts to form a preliminary layered barrier structure. The upper limit of 8 parts significantly enhances hardness, strength, and barrier properties, while avoiding dispersion difficulties and viscosity spikes caused by excessive filler. Ultrasonic treatment at 250-300W for 18-22 minutes prevents crystal destruction or agglomeration of the nanosheets, ensuring the exfoliation of the nanolayers. The exfoliated organically modified nano-montmorillonite nanosheets can be uniformly dispersed in the epoxy resin, forming a "nanomosaic" structure, thus improving the mechanical properties and thermal stability of the protective layer.

[0096] For example, 5 to 6 parts by weight of organically modified nano-montmorillonite are added to a reactor and ultrasonically treated for 19 to 21 minutes under an ultrasonic power of 255 to 290 W.

[0097] For example, 5 parts by weight of organically modified nano-montmorillonite were added to a reactor and ultrasonically treated for 20 minutes at an ultrasonic power of 275W.

[0098] The third step involves lowering the reaction temperature to 55-65°C, adding 30-50 parts by mass of methylhexahydrophthalic anhydride and 0.5-2 parts by mass of benzyl dimethylamine to the reactor, and stirring for 13-17 minutes at a speed of 450-550 rpm.

[0099] In this implementation, lowering the reaction temperature to 55-65℃ can improve production efficiency while ensuring curing effect. The lower limit of the mass fraction of methylhexahydrophthalic anhydride is 30 parts to ensure sufficient reaction of the epoxy groups and avoid incomplete curing; the upper limit of the mass fraction of methylhexahydrophthalic anhydride is 50 parts to prevent excessive anhydride from causing excessive crosslinking density and increased brittleness. The mass fraction of benzyl dimethylamine is 0.5-2 parts. The lower limit of benzyl dimethylamine is 0.5 parts to effectively reduce the activation energy of the curing reaction; the upper limit of benzyl dimethylamine is 2 parts to significantly accelerate the reaction rate while avoiding excessive gel time due to over-addition. Stirring at 450-550 rpm for 13-17 minutes ensures thorough mixing of the modified polycyclic resin coating, preparing for subsequent degassing.

[0100] For example, the reaction temperature is lowered to 57-63°C, and 32-48 parts by mass of methylhexahydrophthalic anhydride and 0.7-1.8 parts by mass of benzyl dimethylamine are added to the reaction vessel and stirred for 14-16 minutes at a speed of 460-540 rpm.

[0101] For example, the reaction temperature was lowered to 60°C, and 40 parts by weight of methylhexahydrophthalic anhydride and 1 part by weight of benzyl dimethylamine were added to the reactor and stirred for 15 minutes at 500 rpm.

[0102] Fourth step: Add 0.3 to 1 part by weight of polyether-modified dimethylsiloxane and 0.2 to 0.5 parts by weight of polysiloxane solution to the reactor, and stir for 7 to 13 minutes at a speed of 150 to 250 rpm.

[0103] In this implementation, the mass fraction of polyether-modified dimethylsiloxane is 0.3 to 1 part, with a lower limit of 0.3 parts to reduce surface tension and pinholes; the upper limit of 1 part to significantly improve leveling while avoiding excessive amounts that could reduce interlayer adhesion. The mass fraction of the polysiloxane solution is 0.2 to 0.5 parts, with a lower limit of 0.2 parts to suppress bubble generation during stirring and curing; the upper limit of 0.5 parts to ensure coating density while avoiding surface defects caused by excessive amounts. Stirring at 150 to 250 rpm for 7 to 13 minutes yields a homogeneous, bubble-free modified polycyclic resin coating.

[0104] For example, 0.5 to 0.8 parts by weight of polyether-modified dimethylsiloxane and 0.3 to 0.4 parts by weight of polysiloxane solution are added to a reaction vessel and stirred at 170 to 230 rpm for 9 to 11 minutes.

[0105] For example, 0.7 parts by weight of polyether-modified dimethylsiloxane and 0.4 parts by weight of polysiloxane solution were added to a reactor and stirred for 10 minutes at a speed of 200 rpm.

[0106] S24. Clean the surface of the light-emitting device and the surface of the circuit board.

[0107] For example, step S24 may include: The first step is to use a low-residue cleaning agent to ultrasonically clean the surface of the light-emitting device and the surface of the circuit board.

[0108] In this implementation, ultrasonic cleaning of the surface of the light-emitting device and the circuit board using a low-residue cleaning agent can thoroughly remove flux residue, dust, and grease from the surface of the light-emitting device and the circuit board.

[0109] In the embodiments of this disclosure, the cleaning agent with low residue can be isopropanol.

[0110] The second step is to dry the food in an oven at 80-100℃ for 10-30 minutes.

[0111] In this implementation, drying in an oven at 80~100℃ for 10~30 minutes can ensure that the surface of the light-emitting device and the surface of the circuit board are completely dry and free of moisture.

[0112] For example, drying in an oven at 90°C for 20 minutes.

[0113] S25. Apply the modified polycyclic resin coating to the surface and sidewalls of the light-emitting device.

[0114] For example, step S25 may include: The first step is to use a precision dispensing machine to coat the modified polycyclic resin coating onto the surface and sidewalls of the light-emitting device. The thickness of the modified polycyclic resin coating is 10~30μm.

[0115] In this implementation, the thickness of the modified polycyclic resin coating is at least 10 μm. Sufficient thickness allows the protective layer to have good barrier properties, which can better prevent moisture, oxygen, sulfides, halides and other substances in the external environment from entering the light-emitting device and improve the reliability of the light-emitting unit. At the same time, the upper limit of this thickness is 30 μm, which avoids cracking problems caused by excessively thick protective layers and further improves the reliability of the light-emitting unit.

[0116] For example, the thickness of the modified polycyclic resin coating is 15 μm or 20 μm.

[0117] The second step is to apply modified polycyclic resin to the connection between the sidewall of the light-emitting device and the circuit board.

[0118] In this implementation, it can be ensured that the light-emitting device is completely covered, which can better prevent water vapor, oxygen, sulfides, halides and other substances in the external environment from entering the interior of the light-emitting device, thereby improving the reliability of the light-emitting unit.

[0119] S26. Curing treatment is applied to the modified polycyclic resin coating to form a protective layer.

[0120] For example, step S26 may include: The first step is to let the device coated with the modified polycyclic resin coating stand at room temperature for 10 to 20 minutes.

[0121] In this implementation, allowing the light-emitting device coated with modified polycyclic resin to stand at room temperature for 10 to 20 minutes can level the modified polycyclic resin coating, forming a smooth surface, reducing defects in the protective layer, and improving the barrier properties of the protective layer.

[0122] The second step is to heat the modified polycyclic resin coating after it has been allowed to stand for 0.9 to 1.1 hours at a temperature of 60 to 80°C.

[0123] In this implementation method, the modified polycyclic resin coating, after being left to stand, is heated at a temperature of 60~80℃ for 0.9~1.1 hours, which can cause the modified polycyclic resin coating to initially gel.

[0124] For example, the modified polycyclic resin coating was cured at a temperature of 70°C for 1 hour.

[0125] The third step is to cure the modified polycyclic resin coating after heating at a temperature of 120~140℃ for 2~3 hours to form the protective layer.

[0126] In this implementation, the modified polycyclic resin coating, after heating, is cured at 120-140°C for 2-3 hours to form the protective layer. This stepped heating helps the solvent escape slowly, reduces internal stress, and ensures a sufficient and complete crosslinking reaction. After curing, a transparent, dense, and strongly adherent protective layer is formed on the surface of the light-emitting device on the circuit board. This protective layer completely isolates the LED chip, wires, and reflective layer from the external environment, thereby improving the weather resistance and long-term reliability of the light-emitting device.

[0127] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A light-emitting unit, characterized in that, The light-emitting unit includes: a circuit board (101), a light-emitting device (102), and a protective layer (103). The light-emitting device (102) is located on the circuit board (101), the light-emitting device (102) is electrically connected to the circuit board (101), and the protective layer (103) covers the surface and sidewalls of the light-emitting device (102); The protective layer (103) is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent and defoamer.

2. The light-emitting unit according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin, the curing agent is methylhexahydrophthalic anhydride, the modifier is terminal epoxy-terminated polydimethylsiloxane, the functional filler is organically modified nano-montmorillonite, the accelerator is benzyl dimethylamine, the leveling agent is polyether-modified dimethylsiloxane, and the defoamer is a defoaming polysiloxane solution.

3. The light-emitting unit according to claim 1 or 2, characterized in that, The epoxy resin comprises 95-105 parts by weight, the curing agent comprises 30-50 parts by weight, the modifier comprises 5-15 parts by weight, the functional filler comprises 3-8 parts by weight, the accelerator comprises 0.5-2 parts by weight, the leveling agent comprises 0.3-1 part by weight, and the defoamer comprises 0.2-0.5 parts by weight.

4. The light-emitting unit according to claim 1 or 2, characterized in that, The thickness of the protective layer (103) is 10~30μm.

5. A method for manufacturing a light-emitting unit, characterized in that, The method for manufacturing the light-emitting unit includes: A light-emitting device is mounted on a circuit board, and the light-emitting device is electrically connected to the circuit board. A protective layer is formed, which covers the surface and sidewalls of the light-emitting device. The protective layer is a modified polycyclic resin layer, and the material of the modified polycyclic resin layer is a mixture of the following materials: epoxy resin, curing agent, modifier, functional filler, accelerator, leveling agent and defoamer.

6. The method for manufacturing the light-emitting unit according to claim 5, characterized in that, The fabrication of the protective layer includes: Production of modified polycyclic aromatic hydrocarbon coatings; The surfaces of the light-emitting device and the circuit board are cleaned. The modified polycyclic resin coating is applied to the surface and sidewalls of the light-emitting device; The modified polycyclic resin coating is cured to form the protective layer.

7. The method for manufacturing the light-emitting unit according to claim 6, characterized in that, The epoxy resin is a bisphenol A type epoxy resin, the curing agent is methylhexahydrophthalic anhydride, the modifier is terminal epoxy-terminated polydimethylsiloxane, the functional filler is organically modified nano-montmorillonite, the accelerator is benzyl dimethylamine, the leveling agent is polyether-modified dimethylsiloxane, and the defoamer is a defoaming polysiloxane solution.

8. The method for manufacturing the light-emitting unit according to claim 7, characterized in that, The preparation of the modified polycyclic resin coating includes: Add 95-105 parts by weight of the bisphenol A type epoxy resin and 5-15 parts by weight of the terminal epoxy polydimethylsiloxane to a reaction vessel, and stir for 28-32 minutes at a reaction temperature of 75-85°C. The organically modified nano-montmorillonite in a mass ratio of 3 to 8 parts was added to the reaction vessel and ultrasonically treated for 18 to 22 minutes under an ultrasonic power of 250 to 300 W. The reaction temperature is lowered to 55-65°C, and 30-50 parts by mass of the methylhexahydrophthalic anhydride and 0.5-2 parts by mass of the benzyl dimethylamine are added to the reaction vessel and stirred for 13-17 minutes at a speed of 450-550 rpm. Add 0.3 to 1 part by weight of the polyether-modified dimethylsiloxane and 0.2 to 0.5 parts by weight of the polysiloxane solution to the reactor, and stir for 7 to 13 minutes at a speed of 150 to 250 rpm.

9. The method for manufacturing a light-emitting unit according to any one of claims 5 to 8, characterized in that, Applying the modified polycyclic resin coating to the surface and sidewalls of the light-emitting device includes: The modified polycyclic resin coating is applied to the surface and sidewalls of the light-emitting device using a precision dispensing machine. The thickness of the modified polycyclic resin coating is 10~30μm. Apply the modified polycyclic resin to the connection between the sidewall of the light-emitting device and the circuit board.

10. The method for manufacturing a light-emitting unit according to any one of claims 6 to 8, characterized in that, The modified polycyclic resin coating is cured to form a protective layer, comprising: The light-emitting device coated with the modified polycyclic resin coating is left to stand at room temperature for 10-20 minutes; The modified polycyclic resin coating, after being allowed to stand, is heated at a temperature of 60-80°C for 0.9-1.1 hours. The modified polycyclic resin coating, after heating, is cured at a temperature of 120~140℃ for 2~3 hours to form the protective layer.

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