A COB module packaging method

Abstract

The present invention relates to a COB module packaging method, comprising: S10: providing a COB substrate, the COB substrate including an array composed of a plurality of light-emitting chips; S20: uniformly dispensing glue on the non-light-emitting chip area of ​​the COB substrate, and dripping opaque glue in parallel in each gap of the array to form a plurality of glue strips; S30: a plurality of glue strips are self-leveled on the COB substrate to form a first glue layer with a thickness of 0.02-0.5 times the height of the light-emitting chip; S40: using transparent glue to cover the first glue layer and the upper half of the light-emitting chip to form a second glue layer. The present invention divides the stacked glue into multiple rows and dispenses them on the COB module, so as to achieve full coverage of the COB module after the glue is self-leveled. The self-leveling relies on the self-weight of the glue to flow to form a flat and smooth surface, which can ensure that the thickness of the first glue layer is uniform, and the surface of the first glue layer is smooth and flat, and the appearance display effect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of LED chip packaging, and in particular to a COB module packaging method. Background Art

[0002] LED packaging refers to the packaging of light-emitting chips. The function of LED packaging is to provide sufficient protection for the chips to prevent them from failing due to long-term exposure to the air or mechanical damage, so as to improve the stability of the chips. In addition, they must be able to transmit light and have high requirements for the concentration and light spot of light.

[0003] COB (Chip on Board) display technology is a new display technology in the LED field. Compared with the traditional POB (Package on Board) display technology, it effectively optimizes the industrial process, saves the installation and transportation costs of lamp beads, and can further reduce the LED spacing. In terms of display effect, it also changes from point lighting of lamp beads to surface lighting effects similar to glass-based panels such as LCD and OLED, making it have the advantages of high reliability, good heat dissipation, material saving, simple process and high pixel density.

[0004] The COB module is mainly composed of three parts, namely the light-emitting layer after packaging on the front, the substrate in the middle, and the driver IC, interface and other electronic materials on the back. The process of assembling the light-emitting layer with the plate, driver IC, etc. into the final product is called packaging. In the current packaging process, a layer of glue is applied around the light-emitting element. One is to isolate the air and prevent the LED from being oxidized; the other is to prevent direct contact with the LED during use or movement to avoid collision damage. During packaging, the light-emitting element, driver IC, interface and other electronic materials are first assembled on the substrate to form a COB semi-finished product, and then a second layer of glue is applied outside the light-emitting element. In the existing small-pitch COB module packaging, transparent glue is used. The surface of the glue layer formed by coating is flat, and there is no obstruction between adjacent light-emitting elements, which is easy to cause light mixing, making the display effect worse; the light-emitting elements emit light in all directions. Except for the forward light, the rest of the light emitted to the side is still refracted by the glue layer to different side directions. Even if the luminous efficiency / light output rate is high, the light output angle is large, and the ink color on the surface of the substrate is not black enough and the surface flatness is poor. The background reflection cannot be effectively absorbed, the picture contrast is low, the amount of light received by the observer is reduced, and the utilization rate of the light output is low, which is easy to cause the defect of insufficient brightness.

[0005] At present, the most effective way to improve the contrast of the picture is to use a black glue layer. At the same time, the blackness of the black glue layer cannot be too large, otherwise it will significantly affect the brightness of the COB module. Since there are errors in the thickness and color of the substrate and the thickness and color of the glue layer, the error is amplified when the black glue layer is encapsulated on the surface of the plate. The black glue layer contains a black agent that significantly absorbs ambient light and a diffusion powder that significantly scatters ambient light. Therefore, in the actual product production process, the thickness error is manifested in color difference, which significantly affects the apparent consistency of the COB module product itself. Summary of the invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defect of poor appearance consistency caused by the superposition of errors between the glue layer and the substrate in the prior art, and to provide a COB module packaging method.

[0007] In order to solve the above technical problems, the present invention provides a COB module packaging method, comprising:

[0008] S10: providing a COB substrate, wherein the COB substrate includes an array of a plurality of light-emitting chips;

[0009] S20: uniformly dispensing glue on the non-light-emitting chip area of ​​the COB substrate, and dripping the opaque glue in parallel in each gap of the array to form a plurality of glue strips;

[0010] S30: multiple glue strips are self-leveled on the COB substrate to form a first glue layer with a thickness of 0.02-0.5 times the height of the light-emitting chip;

[0011] S40: Cover the first glue layer and the upper part of the light-emitting chip with light-transmitting glue to form a second glue layer.

[0012] In one embodiment of the present invention, the gap between adjacent light-emitting chips is greater than 0.6 mm.

[0013] In one embodiment of the present invention, the thickness h of the first glue layer is controlled by the total weight of the glue dispensed.

[0014] h=M / ρ / (A×Ba×b×C),

[0015] Among them, A and B are the length and width of the COB substrate, a and b are the average length and width of the light-emitting components, C is the number of light-emitting components, ρ is the average density of the glue, M is the glue weight, M=mA×cA, where mA is the glue weight of each row, and cA is the number of glue dispensing rows.

[0016] In one embodiment of the present invention, a glue dispensing machine is used for glue dispensing in step S20, and the glue dispensing machine adopts a piezoelectric injection valve or a pneumatic injection valve, and the diameter of the nozzle of the glue dispensing machine is 0.06 mm to 0.2 mm.

[0017] In one embodiment of the present invention, during dispensing, the distance between the nozzle of the dispensing machine and the surface of the COB substrate is 0.3 mm to 3 mm.

[0018] In one embodiment of the present invention, the precision error of the dispensing machine in the XY axis is no more than 0.06 mm.

[0019] In one embodiment of the present invention, the dispensing capacity of the glue dispensing machine is periodically calibrated. During the calibration, before starting to dispensing, the dispensing head sprays the weighing device continuously for multiple times to calculate the first single glue point weight; it sprays continuously again to obtain the second single glue point weight; the relationship between the deviation of the two single glue point weights and the preset deviation is judged. If it is within the preset deviation, the second single glue point weight is used as the dispensing benchmark. If it exceeds the preset deviation, it sprays continuously for multiple times to obtain multiple single glue point weights. According to the deviation trend, the problem is determined and handled.

[0020] In one embodiment of the present invention, the light-transmitting glue is laid on the release film, the light-emitting surface of the COB substrate faces the release film, and the molding mold clamps the release film and the COB substrate in the middle.

[0021] In one embodiment of the present invention, the light-transmitting glue comprises filling powder and defoaming powder, wherein the filling powder accounts for 0-60wt% of the total weight of the non-solid phase colloid, and the defoaming powder accounts for 0-2wt% of the total weight of the non-solid phase colloid.

[0022] In one embodiment of the present invention, the thickness of the second adhesive layer is 0.05 mm to 0.33 mm.

[0023] In one embodiment of the present invention, the COB module is subjected to ultrasonic cleaning and plasma shock before dispensing.

[0024] In one embodiment of the present invention, in step S30, the first adhesive layer is cured and dehumidified.

[0025] The above technical solution of the present invention has the following advantages compared with the prior art:

[0026] 1. By dividing the stacked glue into multiple lines and applying them on the COB module, the COB module can be fully covered after the glue is self-leveled;

[0027] 2. Self-leveling relies on the glue's own weight to flow to form a flat and smooth surface, which can ensure that the thickness of the first glue layer is uniform, and the surface of the first glue layer is smooth and flat, with good appearance display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein

[0029] Figure 1 This is a schematic diagram of multiple filling paths of the COB substrate of the present invention;

[0030] Figure 2 This is a schematic diagram of the COB module structure of the present invention;

[0031] Figure 3 It is a schematic diagram of a filling path;

[0032] Figure 4 It is the thickness distribution diagram of the first glue layer after the rough treatment and the first filling;

[0033] Figure 5 is the thickness distribution diagram of the first glue layer after two fillings after rough treatment;

[0034] Figure 6 It is the thickness distribution diagram of the first glue layer after fine treatment and one-time filling;

[0035] Figure 7 It is the thickness distribution diagram of the first glue layer after two fillings after fine treatment;

[0036] Figure 8 Schematic diagram of the second adhesive layer molding.

[0037] Explanation of the reference numerals in the specification: 1. COB substrate; 2. Light-emitting chip; 3. First adhesive layer; 4. Second adhesive layer; 5. Mold; 6. Release film. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0039] Reference Figure 1 As shown, a COB module packaging method of the present invention uses a PCB board as a substrate of the COB module, comprising:

[0040] S10: Provide a COB substrate, which includes an array of a plurality of light-emitting chips. The COB substrate in this embodiment is a PCB board with light-emitting chips 2 fixed on the surface.

[0041] During packaging, glue needs to be spread on the surface of the PCB board to completely cover the PCB board. If the glue is spread by molding and scraping, on the one hand, the light-emitting chip 2 is arranged at intervals, which may crush or scrape off the light-emitting chip 2. On the other hand, scratches will be formed on the surface of the glue, resulting in an uneven surface of the glue, so that the ink color of the surface of the PCB board is inconsistent, affecting the appearance. Therefore, in an embodiment of the present invention, in S20: the non-light-emitting chip area of ​​the COB substrate is evenly dispensed with glue, and the opaque glue is dripped in each gap of the array in parallel to form a plurality of glue strips; S30: a plurality of glue strips are self-leveled on the COB substrate to form a first glue layer with a thickness of 0.02-0.5 times the height of the light-emitting chip. Self-leveling relies on the self-weight of the glue to flow to form a flat and smooth surface, which can ensure that the thickness of the first glue layer 3 is uniform, and the surface of the first glue layer 3 is smooth and flat, and the appearance display effect is good. During self-leveling, after the opaque glue drips onto the surface of the PCB board, it expands outward to infiltrate the surface of the PCB board, and the glue strip formed by the glue dispensing diffuses to form a glue layer covering the surface of the PCB board. When the amount of glue is large, it is not easy to achieve precise control of the glue dispensing, and the thickness of the glue layer is high, which cannot meet the customer's demand for the thickness of the first glue layer 3. However, when the amount of glue is small, the glue infiltration speed is slow, and it cannot be guaranteed that the glue can completely cover the surface of the PCB. For this reason, in this embodiment, when the non-luminous chip area of ​​the COB substrate is uniformly dispensed, the opaque glue is dripped in each gap of the array in parallel to form a plurality of glue strips. That is, there is a certain distance between the glue strips filled each time, and they do not overlap, so that when the glue strips infiltrate and diffuse on the surface of the PCB board, the adjacent two glue strips contact, and under the action of the intermolecular attraction, the two glue strips can quickly merge into one, thereby increasing the infiltration speed of the opaque glue on the surface of the PCB board, and the thickness of the formed glue layer is thin, which reduces the amount of glue required to cover the PCB board. Specifically, the first adhesive layer 3 can be formed to have a thickness of 0.02-0.5 times the height of the light emitting chip 2 .

[0042] Then, step S40: refer to Figure 2 As shown, a second glue layer 4 is formed by covering the first glue layer 3 and the upper part of the light-emitting chip 2 with a light-transmitting glue. The chip is fully encapsulated to prevent contamination or man-made damage, and the luminous intensity of the light-emitting chip 2 is not affected. Even if there is an error in the total thickness after encapsulation, the light-transmitting glue will not affect the color difference due to the change in thickness. Therefore, when the thickness of the first glue layer 3 is uniform and the surface is smooth and flat, the appearance color of the COB substrate 1 is uniform, which can ensure the consistency of the overall appearance of the COB substrate 1.

[0043] By adopting the processing technology of the present invention, each gap between the light-emitting chips 2 is filled multiple times, and each filling is not stacked up and down, but dispensed side by side. By utilizing the self-leveling property of the glue after dispensing, the first glue layer 3 can be completely covered on the PCB board, and the surface of the first glue layer 3 is flat and smooth, and the thickness is relatively thin, thereby ensuring that the first glue layer 3 has a good apparent display effect. Furthermore, since the second glue layer 4 is a light-transmitting glue, the appearance of the entire COB substrate 1 is beautiful and the display effect is good.

[0044] Of course, refer to Figure 3 As shown, when the gap between the light-emitting chips 2 is too small, the gap can be filled with one dispensing of glue, and multiple fillings are no longer performed. When the gap between adjacent light-emitting chips 2 is large, specifically when the gap between adjacent light-emitting chips 2 is greater than 0.6mm, multiple fillings are performed. The number of fillings is determined by the width of the gap. In this embodiment, when the gap width is between 0.6mm-2.0mm, two fillings are performed, and when the gap width is above 2.0mm, three or more fillings can be performed. Taking the gap between the light-emitting chips 2 as 1.25 as an example, the effect of the present invention is verified. First, the self-leveling COB substrate 1 is horizontally calibrated. Specifically, measure whether the center points of the tops of three consecutive light-emitting chips 2 are at the same height. If so, the COB substrate 1 is horizontal. If not, the COB substrate 1 is leveled. Secondly, the COB substrate 1 is divided into multiple areas, and the difference between the highest point and the lowest point in each area is measured. Finally, the height of the first glue layer 3 in each area is obtained by subtracting the difference from the height of the light-emitting chip 2.

[0045] After the COB substrate 1 is subjected to the same treatment before glue dispensing, glue is dispensed on the COB substrate 1. Figure 3 and Figure 4 As shown, after the COB substrate 1 is roughly processed, the gaps between adjacent light-emitting chips 2 are filled only once. At this time, the thickness of the first adhesive layer 3 in some areas of the PCB board is too thin, and the thickness difference with other areas is large. It can be seen that in this case, only one filling cannot achieve the purpose of making the thickness of the first adhesive layer 3 uniform. Figure 1 and Figure 5 As shown, for the above COB substrate 1, the gaps between adjacent light-emitting chips 2 are filled twice. At this time, the thickness difference of the first adhesive layer 3 in each area of ​​the PCB board is small, that is, the thickness of the first adhesive layer 3 is uniform, and the uniformity of the first adhesive layer 3 is significantly improved compared with one filling.

[0046] In the second embodiment of the present invention, referring to Figure 6 As shown, after the COB substrate 1 is finely processed, the gaps between adjacent light-emitting chips 2 are filled only once. At this time, the thickness of the first adhesive layer 3 on the PCB board is relatively concentrated, but the difference between the highest point and the lowest point of the thickness of the first adhesive layer 3 is still large. Figure 7 As shown, for the COB substrate 1 after the above treatment, the gap between adjacent light-emitting chips 2 is filled twice. At this time, the difference between the highest point and the lowest point of the thickness of the first adhesive layer 3 is small, and the thickness of the first adhesive layer 3 in the half area of ​​the PCB board is the same. It can be seen that the uniformity of the first adhesive layer 3 on the PCB board can be greatly improved by multiple fillings, and the improvement of the uniformity of the thickness of the first adhesive layer 3 is more obvious for the COB substrate 1 after rough treatment, which is relatively finely processed. However, after multiple fillings, the thickness of the first adhesive layer 3 is more uniform for the COB substrate 1 after fine treatment. Specifically, the fine treatment in this embodiment includes ultrasonic cleaning and rinsing, and then high-frequency plasma impact, forming pits on the surface of the PCB board to form a hydrophilic surface on the part of the COB substrate 1 without the light-emitting chip 2.

[0047] Of course, when multiple fillings are performed, the glue dispensing amount of the glue dispensing head each time is different from the glue dispensing amount of a single filling, but the total glue dispensing amount of the COB substrate 1 is guaranteed to be consistent, so that the thickness h of the first glue layer 3 can be controlled by the total weight of the glue dispensing. Specifically:

[0048] h=M / ρ / (A×Ba×b×C),

[0049] Wherein, h is the thickness of the first glue layer 3, A and B are the length and width of the PCB board, a and b are the average length and width of the light-emitting elements, C is the number of light-emitting elements, ρ is the average density of the glue, and M is the glue weight of the glue. M=mA×cA, where mA is the glue weight of each row, and cA is the number of glue-dispensing rows. When the gap between adjacent light-emitting elements is filled only once, the number of glue-dispensing rows is much less than the number of glue-dispensing rows when the gap between adjacent light-emitting elements is filled multiple times. Therefore, when filling multiple times, the glue weight of each row is also less than the glue weight of each row when filling sequentially. Reference Figure 5 As shown, in the two fillings of the present invention, the width of the first filling is L1, and the width of the second filling is L2, then theoretically L2=Lp-L1. Due to errors in actual operation, the widths of L1 and L2 are set to be similar, the sum of L1 and L2 is not less than Lp, and the error between L1 and L2 is less than 0.1mm, so that the amount of glue actually used in the range of L1 and the range of L2 can be guaranteed to be consistent, both of which are half of the amount of glue used in each row in one filling. At the same time, L1 is also determined based on the average line width and actual distribution after actual dispensing. When the size of Lp is larger, 3 or more filling methods can also be selected, and the width of each filling is consistent, so as to ensure that the amount of glue used for each filling is consistent, so that the filling height is consistent, which is more conducive to the rapid realization of self-leveling.

[0050] As a preferred embodiment of the present invention, a glue dispenser is used to dispense opaque glue onto the PCB board in the gap between adjacent light-emitting chips 2, and the glue dispensing head moves back and forth to dispense glue. The glue dispensing machine can specifically control the fluid glue, and drip and apply the opaque glue to the precise position on the surface of the PCB board. The glue dispensing head dispenses glue during the movement in both directions, saving time and improving the efficiency of glue dispensing. The glue dispensing machine adopts a piezoelectric injection valve or a pneumatic injection valve, which can accurately control the colloid flow rate and the position of the glue dots to obtain uniform glue dots, and at the same time achieve accurate positioning of the glue dots with good consistency. The diameter of the nozzle of the glue dispensing machine is 0.06mm~0.2mm, and the nozzle adopts an ordinary nozzle or an extended nozzle. A nozzle that is too small is not suitable for existing general glue and is extremely prone to clogging. A nozzle that is too large has a large spray dispersion, which easily causes glue to remain above the LED chip, affecting the display effect. When dispensing glue, the distance between the nozzle of the glue dispensing machine and the PCB board is 0.3mm~3mm. If the height is too small, the valve body of the glue dispenser will contact the PCB board, affecting the glue dispensing effect. The greater the height, the greater the glue dispensing spray dispersion. When it reaches 3mm, the glue dispensing spray dispersion can still match the gap between the light-emitting elements 2. When it exceeds 5mm, the dispersion degree cannot be effectively controlled by the equipment alone. Furthermore, the precision error of the glue dispenser in the XY axis is no more than 0.06mm. If the precision is insufficient, there will be relatively uneven areas of glue dispensing, and obvious relative bulges will appear after leveling.

[0051] As a preferred embodiment of the present invention, the light-transmitting glue covers the first glue layer 3 and the light-emitting element by molding. The molding process is simple, convenient for controlling the total thickness, and can ensure the smoothness of the light-transmitting glue as much as possible. Figure 8 As shown, the molding step includes: laying the light-transmitting glue on the release film 6, and laying the light-transmitting glue on the upper surface of the release film 6 to prevent the light-transmitting glue from dripping from the release film 6; then the light-emitting surface of the COB substrate 1 is facing the release film 6, that is, the COB substrate 1 is inverted; the molding mold 5 clamps the release film 6 and the COB substrate 1 in the middle, and due to the extrusion of the molding mold 5, the light-transmitting glue spreads to the surroundings, completely covering the light-emitting elements and filling the gaps between adjacent light-emitting elements. Since the second adhesive layer 4 is subjected to pressure when it is formed, in order to prevent the first adhesive layer 3 from deforming under the pressure, in step S20, the first adhesive layer 3 is cured and dehumidified at the same time to prevent the second adhesive layer 4 from being poorly bonded to the first adhesive layer 3.

[0052] Compared with the traditional single-layer molding process, the process of molding the second glue layer 4 on the first glue layer 3 has a thinner actual molding thickness. Therefore, there are two problems. One is that the light-transmitting glue will contact the upper and lower high-temperature areas more quickly before being completely flattened on the release film 6, resulting in the generation of bubbles on the final product; the second is that under the original glue-powder ratio, the excess glue at the new actual thickness will easily stop overflowing and the volume of the glue powder will be greatly compressed due to the uncontrollable directionality of the glue flow itself and the narrowing of the overflow area, resulting in uneven surface display. Based on this, compared with the original single glue layer, a large amount of diffusion powder, a certain amount of filling powder and a certain amount of thickening powder are mainly used to obtain better comprehensive performance; in this embodiment, under the requirements of low actual thickness and high consistency, the light-transmitting glue needs to completely replace the diffusion powder with a narrow particle size distribution with a filling powder with a wide particle size distribution, and at the same time replace the thickening powder with an ultra-small particle size and ultra-low density defoaming powder, that is, the light-transmitting glue includes filling powder and defoaming powder, wherein the filling powder accounts for 0-60wt% of the total weight of the non-solid phase colloid, and the defoaming powder accounts for 0-2wt% of the total weight of the non-solid phase colloid.

[0053] The total thickness H of the molding process controls the display effect. The total thickness is the thickness of the first adhesive layer 33 plus the thickness of the second adhesive layer 4. The total thickness is controlled to be 0.15mm~0.35mm. In the embodiment of the present invention, the thickness of the first adhesive layer 33 is 0.02mm~0.1mm, so the thickness of the second adhesive layer 4 is controlled to be 0.05mm~0.33mm. The thickness of the adhesive layer is controlled by the amount of adhesive. If the amount of adhesive is too small, the flatness of the COB itself after molding is poor, the appearance effect is not good, and when the equipment is abnormal, the process is more likely to be defective; when the amount of adhesive is too large, bright and dark lines are likely to appear at the edge of the molded adhesive when the LED chip emits light, which also affects the display effect.

[0054] Furthermore, whether it is a single-component or two-component epoxy resin glue, as the use time increases, there is a phenomenon of gradual increase in viscosity; in addition, the glue containing filler powder and carbon powder is not a standard Newtonian fluid, and there may be shear thinning or shear thickening; whether it is a pneumatic jet valve or a piezoelectric jet valve, the air supply system is generally a fixed air pressure supply during dispensing, and a dedicated servo motor-controlled screw valve will not be used for air supply. Therefore, as the glue volume in the syringe continues to decrease, the air pressure also decays. Therefore, if the glue is dispensed continuously without periodically adjusting the process, the amount of glue on each COB substrate 1 cannot be effectively controlled. For this reason, in this embodiment, the glue dispensing capacity of the glue dispenser is periodically calibrated.

[0055] Specifically, the dispensing machine is calibrated by taking the following calibration scheme as an example. Before starting to dispense glue, the dispensing head sprays a weighing device, such as a measuring cup with a precision electronic scale at the bottom, for multiple times, such as 50-200 times, and calculates the weight of the first single glue dispense m1, where m1 is the result of the weighing device divided by the number of spraying times. After working for a period of time, the dispensing head sprays the weighing device again to obtain the second single glue dispense weight m2. In this embodiment, 5% is used as the preset deviation. If the deviation is within 5%, it means that the deviation is small and the work can continue. If the deviation exceeds 5%, it means that there is a problem with the dispensing equipment, glue or process, and it needs to be stopped for processing. Specifically, if the deviation between m1 and m2 is within 5%, since the amount of glue sprayed each time changes, and the amount of glue required for each gap remains unchanged, the number of points sprayed needs to correspond to the change of m2. According to the m2 glue weight, the number of points mA / m2 sprayed in each gap on the COB substrate 1 is recalibrated. If the deviation between m1 and m2 exceeds 5%, multiple continuous injections are performed to obtain multiple single-point glue weights m3, m4, etc. According to the deviation trend, the problem is determined and handled. For example, if the deviation continues to expand, the viscosity of the glue may have risen too much. At this time, new glue needs to be replaced, or the glue dispensing process, such as the heating temperature of the nozzle, needs to be adjusted. During the production process, the calibration cycle is 5-30 minutes; the use and replacement cycle of a tube of glue needs to be controlled within 6 hours.

[0056] In the present invention, the glue layer near the surface of the COB substrate is formed into a light-proof first glue layer 3 by dispensing, and the stacked glue is divided into multiple lines for dispensing to ensure that the first glue layer 3 fully covers the COB substrate 1, and the thickness of the first glue layer 3 is uniform and can reach a relatively thin thickness. The first glue layer 3 is realized by self-leveling, and the surface is flat and smooth, and the appearance effect is good, thereby ensuring that the overall appearance effect of the COB substrate 1 is good.

[0057] Obviously, the above embodiments are merely examples for the purpose of clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the present invention.

Claims

1. A COB module packaging method, characterized in that: include: S10: providing a COB substrate, wherein the COB substrate includes an array of a plurality of light-emitting chips; S20: uniformly dispensing glue on the non-light-emitting chip area of ​​the COB substrate, and dripping the opaque glue in parallel in each gap of the array to form a plurality of glue strips; S30: multiple glue strips are self-leveled on the COB substrate to form a first glue layer with a thickness of 0.02-0.5 times the height of the light-emitting chip; The thickness h of the first glue layer is controlled by the total weight of the glue dispensed. h=M / ρ / (A×Ba×b×C), Wherein, A and B are the length and width of the COB substrate, a and b are the average length and width of the light-emitting element, C is the number of light-emitting elements, ρ is the average density of the glue, M is the glue weight of the glue, M=mA×cA, where mA is the glue weight of each row, and cA is the number of glue dispensing rows; S40: Cover the first glue layer and the upper part of the light-emitting chip with light-transmitting glue to form a second glue layer.

2. A COB module packaging method according to claim 1, characterized in that: The gap between adjacent light-emitting chips is greater than 0.6 mm.

3. A COB module packaging method according to claim 1, characterized in that: In step S20, a glue dispensing machine is used for glue dispensing. The glue dispensing machine adopts a piezoelectric injection valve or a pneumatic injection valve. The diameter of the nozzle of the glue dispensing machine is 0.06 mm to 0.2 mm.

4. A COB module packaging method according to claim 3, characterized in that: During dispensing, the distance between the nozzle of the dispensing machine and the surface of the COB substrate is 0.3 mm to 3 mm.

5. A COB module packaging method according to claim 3, characterized in that: The precision error of the dispensing machine on the XY axis is no more than 0.06mm.

6. A COB module packaging method according to claim 3, characterized in that: The dispensing capacity of the dispensing machine is periodically calibrated. During the calibration, before starting dispensing, the dispensing head sprays the weighing device continuously for multiple times to calculate the first single dispensing weight; the dispensing head sprays continuously again to obtain the second single dispensing weight; the relationship between the deviation of the two single dispensing weights and the preset deviation is judged. If it is within the preset deviation, the second single dispensing weight is used as the dispensing benchmark. If it exceeds the preset deviation, multiple continuous sprays are performed to obtain multiple single dispensing weights. According to the deviation trend, the problem is determined and handled.

7. A COB module packaging method according to claim 1, characterized in that: The light-transmitting glue is laid on the release film, the light-emitting surface of the COB substrate faces the release film, and the molding mold clamps the release film and the COB substrate in the middle.

8. A COB module packaging method according to claim 1, characterized in that: The light-transmitting glue comprises filling powder and defoaming powder, wherein the filling powder accounts for 0-60wt% of the total weight of the non-solid phase colloid, and the defoaming powder accounts for 0-2wt% of the total weight of the non-solid phase colloid.

9. A COB module packaging method according to claim 1, characterized in that: The thickness of the second adhesive layer is 0.05mm~0.33mm.

10. A COB module packaging method according to claim 1, characterized in that: Before dispensing, the COB module is ultrasonically cleaned and plasma impacted.

11. A COB module packaging method according to claim 1, characterized in that: In step S30 , the first adhesive layer is cured and dehumidified.

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