TOP LED lamp bead preparation method and TOP LED lamp bead preparation method

Abstract

The invention discloses a TOP LED lamp bead and a preparation method thereof, and relates to the field of semiconductor photoelectric devices. The preparation method of the TOP LED lamp bead comprises the following steps that S1, a substrate is provided, the front face of the substrate is provided with a die bonding area and a wire bonding area, the back face of the substrate is provided with a pin area, the pin area and the wire bonding area are correspondingly arranged, the wire bonding area and the pin area are electrically connected through a conducting medium, and a through hole is filled with the conducting medium; s2, fixing an LED chip on the die bonding area, and electrically connecting the LED chip with the wire bonding area; s3, forming a first packaging adhesive layer on the front surface of the substrate to obtain a middle lamp bead; s4, a TOP support is provided, the TOP support comprises a support body, a reflection cup and pins, and a lamp bead fixing area is defined by the front face of the support body and the reflection cup; s5, a middle lamp bead is fixed in the lamp bead fixing area, and a pin area on the back face of the middle lamp bead is electrically connected with a pin; and S6, forming a second packaging adhesive layer to obtain a TOP LED lamp bead finished product. By means of the TOP LED lamp bead, the air tightness and reliability of the TOP LED lamp bead can be improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor optoelectronic devices, and in particular to a method for preparing a TOP LED lamp bead and a preparation method thereof. Background Art

[0002] With the wide application of display technology, the application scenarios are also diversified, and the application of LED display devices, the key components of display screens, has become more important. Therefore, the reliability performance requirements of lamp beads are getting higher and higher. From the perspective of LED lamp bead technology, the packaging technology and product structure have an important impact on its performance and reliability. The early process routes of LED lamp beads are generally solid crystal, wire welding, glue dispensing, blanking, light splitting, taping, packaging and shipment. As the market requirements are getting higher and higher, the use environment is becoming more and more diverse, especially under conditions of heavy humidity. Under the current technical solutions, water vapor can easily penetrate, causing the lamp beads to burn out, and in severe cases, caterpillars will form, so the requirements for the air tightness of the product are getting higher and higher.

[0003] At present, the most widely used TOP LED device in outdoor display screens is the TOP stamping injection molding bracket. The bracket is divided into two sides. The front side is composed of PPA and the metal part after stamping as the functional area of ​​the lamp bead. The PPA part is formed into a bowl by injection molding to protect the functional area. The back side is composed of PPA and pins. The pins are formed by bending. The front functional area uses silver glue or insulating glue to fix the chip in the functional area, and then the bonding wire is welded to the chip electrode and the functional area to form an electrical connection between the chip and the functional area. The bracket is sealed by the glue dispensing process, and then the material is blanked into RGB three-primary color lamp beads. The existing TOP LED mostly uses epoxy resin as the encapsulation glue. Due to the high temperature of the lamp bead during use, the lamp bead ages, and the sealing of the epoxy resin is weakened, which makes it easy for water vapor to penetrate, resulting in lamp bead burning and poor metal migration. In addition, the thermal expansion coefficients of the epoxy resin used in the encapsulation and the PPA resin of the bracket are inconsistent, and gaps are easily generated at the junction of the two, which makes it easy for water vapor to penetrate, resulting in burning and poor metal migration, reducing reliability. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a TOP LED lamp bead and a preparation method thereof, which can effectively improve the air tightness and improve the reliability of the lamp bead.

[0005] In order to solve the above problems, the present invention discloses a method for preparing a TOP LED lamp bead, which comprises the following steps:

[0006] S1. Provide a substrate, wherein the front side of the substrate is provided with at least one crystal bonding area and at least one wire bonding area, and the back side of the substrate is provided with at least two pin areas, wherein the pin areas are arranged corresponding to the wire bonding areas, and the wire bonding areas are electrically connected to the pin areas through a conductive medium, and the conductive medium is filled in a through hole located on the substrate;

[0007] S2, fixing at least one LED chip on the die-bonding area and forming an electrical connection with the wire bonding area;

[0008] S3, forming a first packaging adhesive layer on the front side of the substrate to obtain an intermediate lamp bead;

[0009] S4, providing a TOP bracket, wherein the TOP bracket comprises a bracket, a reflector cup and pins, and the front side of the bracket and the reflector cup enclose a lamp bead fixing area;

[0010] S5, fixing the middle lamp bead in the lamp bead fixing area, and electrically connecting the pin area on the back of the middle lamp bead to the pin;

[0011] S6. Form a second encapsulation adhesive layer to obtain a finished TOP LED lamp bead.

[0012] As an improvement of the above technical solution, the through hole is filled with a conductive medium layer and a protective adhesive layer;

[0013] The conductive medium layer is arranged on the inner wall of the through hole close to the solid crystal area or the wire bonding area, and the protective adhesive layer is arranged on the side of the conductive medium layer away from the solid crystal area or the wire bonding area to protect the conductive medium.

[0014] As an improvement of the above technical solution, the cross section of the through hole is circular, and the through hole is filled with a ring-shaped conductive medium layer and a cylindrical protective rubber layer, and the protective rubber layer is arranged on the inner side of the conductive medium layer;

[0015] The ratio of the diameter of the protective adhesive layer to the inner diameter of the through hole is 0.5-0.9:1.

[0016] As an improvement of the above technical solution, step S1 includes:

[0017] S11, providing a substrate;

[0018] S12, forming a through hole on the substrate;

[0019] S13, forming a conductive dielectric layer and a protective adhesive layer in the through hole;

[0020] S14, forming a crystal bonding area and a wire bonding area on the front side of the substrate, and forming a lead area on the back side of the substrate.

[0021] As an improvement of the above technical solution, step S3 includes:

[0022] S31, forming a first packaging adhesive layer on the front surface of the substrate, and performing molding to obtain a packaging unit;

[0023] S32, cutting the packaging unit into a plurality of intermediate lamp beads; each of the intermediate lamp beads includes an LED chip.

[0024] As an improvement of the above technical solution, step S3 includes:

[0025] S31, forming a first packaging adhesive layer on the front side of the substrate, and performing molding to obtain a packaging unit; wherein the first packaging adhesive layer covers the protective adhesive layer;

[0026] S32, cutting the packaging unit into a plurality of intermediate lamp beads; each of the intermediate lamp beads includes an LED chip;

[0027] Wherein, in the first direction, the packaging unit is cut along a cutting line located on the protective adhesive layer, so that the outer side of the conductive medium layer is wrapped with the protective adhesive layer.

[0028] As an improvement of the above technical solution, the front side of the substrate is provided with a die-bonding functional area, a wire bonding functional area and a connection functional area arranged alternately along the second direction; the back side of the substrate is provided with a pin functional area arranged along the second direction;

[0029] The crystal-bonding functional area is provided with a plurality of crystal-bonding areas arranged evenly or unevenly along a first direction;

[0030] The welding wire functional area is provided with a plurality of welding wire areas arranged evenly or unevenly along the first direction;

[0031] The connection function area is provided with a plurality of through holes arranged evenly or unevenly in the first direction;

[0032] The pin function area is provided with a plurality of pin areas which are arranged evenly or unevenly along the first direction.

[0033] As an improvement of the above technical solution, the crystal bonding area is electrically connected to the conductive medium in the through hole through a connecting wire;

[0034] The wire bonding area is electrically connected to the conductive medium in the through hole through a connecting wire.

[0035] As an improvement of the above technical solution, the protective adhesive layer, the first encapsulation adhesive layer, and the second encapsulation adhesive layer are made of the same material.

[0036] Correspondingly, the present invention also discloses a TOP LED lamp bead, which is prepared by the above-mentioned preparation method of the TOP LED lamp bead.

[0037] The implementation of the present invention has the following beneficial effects:

[0038] 1. In the preparation method of the TOP LED lamp bead in one embodiment of the present invention, the LED chip is first fixed on the substrate and encapsulated to form an intermediate lamp bead, and then the TOP bracket to which the intermediate lamp bead is fixed is formed, and then a second encapsulation adhesive layer is formed to obtain a finished product. That is, the TOP LED lamp bead in this embodiment is encapsulated twice, which greatly improves the airtightness of the LED lamp bead, avoids defects such as burnout and metal migration caused by water vapor infiltration into the interior of the lamp bead, and greatly improves the reliability of the LED lamp bead.

[0039] 2. In the preparation method of the TOP LED lamp bead in one embodiment of the present invention, during the first packaging process, a conductive medium layer and a protective adhesive layer are formed in the through hole used for conduction. After subsequent cutting, the protective adhesive layer is attached to the outside of the conductive medium layer, which effectively prevents water vapor from corroding the conductive medium layer and further improves the reliability of the LED lamp bead. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 is a schematic diagram of the front structure of a substrate in one embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of the back structure of a substrate in one embodiment of the present invention;

[0042] Figure 3 It is a schematic diagram of the front structure of the middle lamp bead in one embodiment of the present invention;

[0043] Figure 4 is a schematic diagram of the cross-sectional structure of a middle lamp bead in one embodiment of the present invention;

[0044] Figure 5 is a schematic structural diagram of a TOP bracket in one embodiment of the present invention;

[0045] Figure 6 1 is a schematic diagram of the cross-sectional structure of a TOP LED lamp bead in one embodiment of the present invention;

[0046] Figure 7 1 is a schematic diagram of the front structure of a TOP LED lamp bead in one embodiment of the present invention;

[0047] Figure 8 It is a schematic diagram of the back structure of a TOP LED lamp bead in one embodiment of the present invention;

[0048] In the figure, 1 is a substrate, 11 is a solid crystal functional area, 12 is a welding wire functional area, 13 is a connection functional area, 14 is a pin functional area, 15 is a through hole, 111 is a solid crystal area, 121 is a welding wire area, 141 is a pin area, 151 is a conductive medium layer, 152 is a protective adhesive layer, 16 is a connecting wire, 17 is a cutting wire, 2 is an LED chip, 3 is a bonding wire, 4 is a first packaging adhesive layer, 5 is a middle lamp bead, 6 is a TOP bracket, 61 is a bracket, 62 is a reflective cup, 63 is a pin, and 7 is a second packaging adhesive layer. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in further detail below.

[0050] An embodiment of the present invention provides a method for preparing a TOP LED lamp bead, which comprises the following steps:

[0051] S1, providing a substrate 1; see Figure 1 and Figure 2 The front side of the substrate 1 is provided with a crystal bonding area 111 and a wire bonding area 121, and the back side is provided with a lead area 141;

[0052] S2, fixing the LED chip 2 on the die-bonding area 111 and forming an electrical connection with the wire bonding area 121;

[0053] S3, forming a first packaging adhesive layer 4 on the front side of the substrate 1 to obtain an intermediate lamp bead 5;

[0054] S4, provide TOP bracket 6; see Figure 6 , the TOP bracket 6 includes a bracket 61, a reflector cup 62 and a pin 63, and the front of the bracket 61 and the reflector cup 62 enclose a lamp bead fixing area;

[0055] S5, fixing the middle lamp bead 5 in the lamp bead fixing area, and electrically connecting the pin area 141 on the back of the middle lamp bead 5 to the pin 63;

[0056] S6, forming a second encapsulation adhesive layer 7 to obtain a finished TOP LED lamp bead.

[0057] Based on the above preparation method, the LED chip 2 is packaged twice in different ways, which greatly improves the airtightness and reliability of the TOP LED lamp bead.

[0058] Specifically, in one embodiment, in step S1, the substrate 1 may be an insulating plate, which may be a BT board or a PCB board commonly used in the art, but is not limited thereto. The substrate 1 is planar.

[0059] See also Figure 1 and Figure 2The front side of the substrate 1 is provided with at least one crystal-fixing area 111 and at least one wire-bonding area 121, and the back side of the substrate 1 is provided with at least two pin areas 141, the pin areas 141 are provided correspondingly to the wire-bonding areas 121, and the wire-bonding areas 121 and the pin areas 141 are electrically connected through a conductive medium, and the conductive medium is filled in the through hole 15 located on the substrate 1. Among them, the crystal-fixing area 111 is used to fix the LED chip 2, and the wire-bonding area 121, the pin area 141, and the conductive medium are used to form an electrical connection with the LED chip 2, so as to pass current into the LED chip 2 and light up the LED chip 2.

[0060] The crystal-bonding area 111, the wire-bonding area 121, and the lead area 141 are all conductive thin layers on the surface of the substrate 1, for example, they can be copper foil formed by lamination, or conductive thin layers formed by screen printing, embossing, electroplating, etc., but are not limited thereto. Preferably, in one embodiment, the crystal-bonding area 111, the wire-bonding area 121, and the lead area 141 are all copper foils, which can be formed into crystal-bonding areas 111, wire-bonding areas 121, and lead areas 141 with specific patterns by lamination and etching processes.

[0061] Specifically, in one embodiment, each LED chip 2 is provided with a corresponding solid crystal area 111 and two pin areas 141 to electrically connect the N electrode and the P electrode of the LED chip 2, respectively, but not limited thereto. Preferably, in one embodiment, one electrode of each LED chip 2 is electrically connected to the solid crystal area 111, and the other electrode is electrically connected to the wire bonding area 121. Based on the above scheme, a larger solid crystal area 111 can be used to improve the heat dissipation function and further improve the reliability of the TOP LED lamp bead.

[0062] Specifically, the through hole 15 penetrates the substrate 1 along the thickness direction of the substrate 1 to form an electrical connection between the solid crystal area 111 / wire bonding area 121 and the pin area 141 through the conductive medium. The cross-section of the through hole 15 may be circular, square, elliptical or triangular, but is not limited thereto. The conductive medium may partially or completely fill the through hole 15. Preferably, in one embodiment, the through hole 15 is filled with a conductive medium layer 151 and a protective adhesive layer 152; the conductive medium layer 151 is disposed on the inner wall of the through hole 15 on the side close to the solid crystal area 111 or the wire bonding area 121, and the protective adhesive layer 152 is disposed on the side of the conductive medium layer 151 away from the solid crystal area 111 or the wire bonding area 121. See Figure 3 and Figure 4Based on this arrangement, after the substrate 1 is cut later, the protective adhesive layer 152 is located on the outside of the conductive medium layer 151, thereby effectively protecting the conductive medium layer 151 and preventing water vapor erosion. More preferably, in one embodiment, the cross section of the through hole 15 is circular, and the through hole 15 is filled with a ring-shaped conductive medium layer 151 and a cylindrical protective adhesive layer 152, and the protective adhesive layer 152 is arranged on the inside of the conductive medium layer 151; based on this arrangement, after the substrate 1 is cut later, the protective adhesive layer 152 is located on the outside of the conductive medium layer 151, thereby protecting the conductive medium layer 151. Specifically, the ratio of the diameter of the protective adhesive layer 152 to the inner diameter of the through hole 15 is 0.5 to 0.9:1. Based on this ratio, firstly, it ensures that the through hole 15 occupies a smaller area to avoid drilling too large a hole and damaging the substrate 1; secondly, it ensures that a conductive medium layer 151 of appropriate thickness is formed in the through hole 15 to ensure good electrical connection; thirdly, a protective adhesive layer 152 of appropriate thickness is formed to prevent water vapor from invading the conductive medium layer 151.

[0063] Specifically, in one embodiment, the solid crystal area 111 / wire bonding area 121 contacts the conductive medium in the through hole 15 to electrically connect the electrode of the LED chip 2 to the pin area 141. In another embodiment, the solid crystal area 111 and the conductive medium in the through hole 15 are electrically connected through the connecting wire 16; the wire bonding area 121 and the conductive medium in the through hole 15 are electrically connected through the connecting wire 16. Based on this implementation, water vapor can pass through a farther area to conduct the LED chip 2, further improving the reliability of the TOP LED lamp bead.

[0064] Specifically, in one embodiment, in order to improve production efficiency, a plurality of die-bonding regions 111, wire bonding regions 121 and lead regions 141 are provided on the surface of the substrate 1. For more details, see Figure 1 and Figure 2 In one embodiment, the front side of the substrate 1 is provided with a solid crystal function area 11, a wire bonding function area 12 and a connection function area 13 arranged alternately along the second direction; the back side of the substrate 1 is provided with a pin function area 14 arranged along the second direction; the solid crystal function area 11 is provided with a plurality of solid crystal areas 111 arranged with uniform or uneven spacing along the first direction; preferably, the plurality of solid crystal areas 111 are uniformly spaced. The wire bonding function area 12 is provided with a plurality of wire bonding areas 121 arranged with uniform or uneven spacing along the first direction; preferably, the plurality of wire bonding areas 121 are uniformly spaced, and the connection function area 13 is provided with a plurality of through holes 15 arranged with uniform or uneven spacing along the first direction; preferably, the plurality of through holes 15 are uniformly spaced. The pin function area 14 is provided with a plurality of pin areas 141 arranged with uniform or uneven spacing along the first direction. Preferably, the plurality of pin areas 141 are uniformly spaced. Based on this embodiment, the first packaging of a plurality of intermediate lamp beads 5 can be completed at one time, greatly improving production efficiency.

[0065] Specifically, in one embodiment, step S1 includes:

[0066] S11, providing a substrate 1;

[0067] S12, forming a through hole 15 on the substrate 1;

[0068] Specifically, the through hole 15 can be formed by a drilling process, but is not limited thereto. Preferably, in one embodiment, when the die-bonding region 111 is formed by a copper foil lamination process, the copper foil is firstly laminated on the substrate 1 and then the through hole 15 is formed.

[0069] S13, forming a conductive dielectric layer 151 and a protective adhesive layer 152 in the through hole 15;

[0070] Specifically, the conductive medium is formed by a copper deposition process or an electroplating process, but is not limited thereto. Preferably, the conductive medium is formed by a copper deposition process. The protective adhesive layer 152 can be formed by a dispensing curing process.

[0071] S14 , forming a crystal bonding area 111 and a wire bonding area 121 on the front surface of the substrate 1 , and forming a lead area 141 on the back surface of the substrate 1 .

[0072] The crystal bonding area 111, the wire bonding area 121 and the pin area 141 can be formed by screen printing, stamping, electroplating, etc., but are not limited thereto. Preferably, in one embodiment, the crystal bonding area 111, the wire bonding area 121 and the pin area 141 are formed by etching the copper foil pressed on the substrate 1.

[0073] Specifically, in step S2, the LED chip 2 can be fixed on the solid crystal area 111 by adhesive, but it is not limited thereto. Preferably, in one embodiment, different types of adhesive can be used according to the different structures of the LED chip 2. For example, when a vertical LED chip 2 is used, a conductive adhesive is used to bond one side of the LED chip 2 to the solid crystal area 111; when a horizontal LED chip 2 is used, an insulating adhesive is used to bond the LED chip 2 to the solid crystal area 111.

[0074] For details, see Figure 3 and Figure 4 In step S2, the LED chip 2 can be electrically connected to the wire bonding area 121 by the bonding wire 3, but the present invention is not limited thereto. Preferably, in one embodiment, the other electrode of the LED chip 2 can also be electrically connected to the die-bonding area 111 by the bonding wire 3.

[0075] Specifically, in step S3, the encapsulation glue may be first dispensed on the front surface of the substrate 1 and then thermally cured, but is not limited thereto. Preferably, in one embodiment, the encapsulation glue is first dispensed on the front surface of the substrate 1 and then molded to form a first encapsulation glue layer 4. Through molding, a cubic structure middle lamp bead 5 may be formed, which is convenient for subsequent secondary packaging.

[0076] Preferably, in one embodiment, step S3 includes:

[0077] S31, forming a first packaging adhesive layer 4 on the front side of the substrate 1, and performing molding to obtain a packaging unit;

[0078] S32, cutting the packaging unit into a plurality of intermediate lamp beads 5; for details, see Figure 3 and Figure 4 , each middle lamp bead 5 includes an LED chip 2.

[0079] Preferably, in another embodiment, step S3 includes:

[0080] S31, forming a first packaging glue layer 4 on the front side of the substrate 1, and molding to obtain a packaging unit; wherein, see Figure 4 , the first packaging glue layer 4 covers the protective glue layer 152. Based on this structure, the conductive medium layer 151 and the connecting wire 16 in the through hole 15 are multiple protected, thereby improving reliability. It should be noted that in the TOP LED lamp bead, first, because the pin 63 is in a bent structure, it is easy to produce a gap between the pin 63 and the reflective cup 62; second, because the pin 63 conducts heat quickly and the heat is concentrated, the reflective cup 62 (generally made of PPA material) in contact with the pin 63 is easy to produce a gap due to thermal expansion, which makes it easy for water vapor to enter the lamp bead along the gap between the pin 63 and the reflective cup 62, thereby corroding the lamp bead, etc. In this embodiment, first, a secondary packaging is performed, and second, a protective glue layer 152 is provided on the outside of the pin area 141 in contact with the pin 63, so that even after water vapor enters, it is less likely to contact the pin area 141, and then extend to the LED chip 2 and the bonding wire 3 through the pin area 141. Thirdly, the first packaging adhesive layer 4 is also covered on the protective adhesive layer 152, which further prevents water vapor from contacting the bonding wires 3 and the LED chips 2, thereby greatly improving reliability.

[0081] S32, cutting the packaging unit into a plurality of intermediate lamp beads 5; each intermediate lamp bead 5 includes an LED chip 2; wherein, in the first direction, the packaging unit is cut along the cutting line 17 located on the protective adhesive layer 152, so that the outer side of the conductive medium layer 151 wraps the protective adhesive layer 152. It should be noted that, see Figure 1 , Figure 2In order to obtain a middle lamp bead 5 containing only one LED chip 2, a plurality of parallel cutting lines 17 are further provided in the second direction of the substrate 1. The first direction and the second direction intersect, and illustratively, the first direction is a horizontal direction, and the second direction is a vertical direction, and the two are perpendicular, but not limited thereto.

[0082] Specifically, in step S4, see Figure 6 , the TOP bracket 6 includes a bracket 61, a reflector cup 62 and a pin 63, wherein the pin 63 is a bent pin, the top of which is located above the bracket 61, and the bottom is located below the bracket 61 after being bent. The front of the bracket 61 and the reflector cup 62 enclose a lamp bead fixing area, and the pin 63 located on the front of the bracket 61 extends into the lamp bead fixing area to facilitate the later electrical connection with the middle lamp bead 5. Specifically, the bracket 61 and the reflector cup 62 are both formed by a glue injection process, and they can be made of the same material, but are not limited to this. It should be noted that in this embodiment, a plurality of fixing units consisting of brackets 61, reflector cups 62 and pins 63 are provided on the TOP bracket 6. More specifically, the TOP bracket 6 includes a blanking bracket (not shown in the figure), and a plurality of fixing units connected to the blanking bracket.

[0083] Specifically, in step S5, the middle lamp bead 5 can be fixed in the lamp bead fixing area by welding, bonding and other processes, and electrically connected to the pin 63, but is not limited thereto. Preferably, in one embodiment, the middle lamp bead 5 is fixed by solder paste welding. Among them, each fixing unit composed of the bracket 61, the reflector cup 62 and the pin 63 can fix one or more middle lamp beads 5. Preferably, refer to Figure 7 and Figure 8 In each fixing unit, three middle lamp beads 5 are fixed, which are respectively a middle lamp bead 5 that can emit red light, a middle lamp bead 5 that can emit green light, and a middle lamp bead 5 that can emit blue light, to form a display unit. Accordingly, each fixing unit is provided with two pins 63 to respectively connect the P electrodes and N electrodes of the three lamp beads.

[0084] Specifically, in step S6, glue is dispensed on the middle lamp bead 5 and cured to form the second encapsulation glue layer 7. Further, the blanking bracket is separated to obtain the TOP LED lamp bead, and its specific structure is as follows: Figure 6 shown.

[0085] Preferably, in one embodiment, the protective adhesive layer 152, the first encapsulation adhesive layer 4, and the second encapsulation adhesive layer 7 are made of the same material, so that they have substantially the same thermal expansion after being subjected to the heat of the LED chip 2, thereby reducing gaps for water vapor to enter.

[0086] In summary, in the preparation method of the TOP LED lamp bead in one embodiment of the present invention, the LED chip 2 is first fixed on the substrate 1, and encapsulated to form the middle lamp bead 5, and then the TOP bracket 6 to which the middle lamp bead 5 is fixed is formed, and then the second encapsulation adhesive layer 7 is formed to obtain the finished product, that is, the TOP LED lamp bead in this embodiment is encapsulated twice, which greatly improves the airtightness of the LED lamp bead, avoids defects such as burnout and metal migration caused by water vapor infiltration into the interior of the lamp bead, and greatly improves the reliability of the LED lamp bead. In the preparation method of the TOP LED lamp bead in one embodiment of the present invention, during the first encapsulation process, a conductive medium layer 151 and a protective adhesive layer 152 are formed in the through hole 15 for conduction, and the protective adhesive layer 152 is attached to the outside of the conductive medium layer 151 after subsequent cutting, which effectively avoids water vapor from corroding the conductive medium layer 151, and further improves the reliability of the LED lamp bead.

[0087] The above is a preferred embodiment of the invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the invention. These improvements and modifications are also considered to be within the scope of protection of the invention.

Claims

1. A method for preparing a TOP LED lamp bead, characterized in that: The following steps are involved: S1. Provide a substrate, wherein the front side of the substrate is provided with at least one crystal bonding area and at least one wire bonding area, and the back side of the substrate is provided with at least two pin areas, wherein the pin areas are arranged corresponding to the wire bonding areas, and the wire bonding areas are electrically connected to the pin areas through a conductive medium, and the conductive medium is filled in a through hole located on the substrate; S2, fixing at least one LED chip on the die-bonding area and forming an electrical connection with the wire bonding area; S3, forming a first packaging adhesive layer on the front side of the substrate to obtain an intermediate lamp bead; S4, providing a TOP bracket, wherein the TOP bracket comprises a bracket, a reflector cup and pins, and the front side of the bracket and the reflector cup enclose a lamp bead fixing area; S5, fixing the middle lamp bead in the lamp bead fixing area, and electrically connecting the pin area on the back of the middle lamp bead to the pin; S6. Form a second encapsulation adhesive layer to obtain a finished TOP LED lamp bead.

2. The method for preparing a TOP LED lamp bead according to claim 1, characterized in that: The through hole is filled with a conductive medium layer and a protective adhesive layer; The conductive medium layer is arranged on the inner wall of the through hole close to the solid crystal area or the wire bonding area, and the protective adhesive layer is arranged on the side of the conductive medium layer away from the solid crystal area or the wire bonding area to protect the conductive medium.

3. The method for preparing a TOP LED lamp bead according to claim 1, characterized in that: The cross section of the through hole is circular, and the through hole is filled with a ring-shaped conductive medium layer and a cylindrical protective rubber layer, and the protective rubber layer is arranged on the inner side of the conductive medium layer; The ratio of the diameter of the protective adhesive layer to the inner diameter of the through hole is 0.5-0.9:

1.

4. The method for preparing a TOP LED lamp bead according to claim 2 or 3, characterized in that: Step S1 includes: S11, providing a substrate; S12, forming a through hole on the substrate; S13, forming a conductive dielectric layer and a protective adhesive layer in the through hole; S14, forming a crystal bonding area and a wire bonding area on the front side of the substrate, and forming a lead area on the back side of the substrate.

5. The method for preparing a TOP LED lamp bead according to claim 1, characterized in that: Step S3 includes: S31, forming a first packaging adhesive layer on the front surface of the substrate, and performing molding to obtain a packaging unit; S32, cutting the packaging unit into a plurality of intermediate lamp beads; each of the intermediate lamp beads includes an LED chip.

6. The method for preparing a TOP LED lamp bead according to claim 2 or 3, characterized in that: Step S3 includes: S31, forming a first packaging adhesive layer on the front side of the substrate, and performing molding to obtain a packaging unit; wherein the first packaging adhesive layer covers the protective adhesive layer; S32, cutting the packaging unit into a plurality of intermediate lamp beads; each of the intermediate lamp beads includes an LED chip; Wherein, in the first direction, the packaging unit is cut along a cutting line located on the protective adhesive layer, so that the outer side of the conductive medium layer is wrapped with the protective adhesive layer.

7. The method for preparing a TOP LED lamp bead according to claim 1, characterized in that: The front side of the substrate is provided with a die-bonding functional area, a wire bonding functional area and a connection functional area arranged alternately along the second direction; the back side of the substrate is provided with a pin functional area arranged along the second direction; The crystal-bonding functional area is provided with a plurality of crystal-bonding areas arranged evenly or unevenly along a first direction; The welding wire functional area is provided with a plurality of welding wire areas arranged evenly or unevenly along the first direction; The connection function area is provided with a plurality of through holes arranged evenly or unevenly in the first direction; The pin function area is provided with a plurality of pin areas which are arranged evenly or unevenly along the first direction.

8. The method for preparing a TOP LED lamp bead according to claim 1, characterized in that: The crystal bonding area is electrically connected to the conductive medium in the through hole via a connecting wire; The wire bonding area is electrically connected to the conductive medium in the through hole through a connecting wire.

9. The method for preparing a TOP LED lamp bead according to claim 2 or 3, characterized in that: The protective adhesive layer, the first encapsulation adhesive layer and the second encapsulation adhesive layer are made of the same material.

10. A TOP LED lamp bead, characterized in that: The TOP LED lamp bead is prepared by the preparation method of any one of claims 1 to 9.

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