CN115132899A

CN115132899A - Manufacturing method of flip LED lamp bead

Info

Publication number: CN115132899A
Application number: CN202110325111.XA
Authority: CN
Inventors: 张汉春; 江忠永
Original assignee: Hangzhou Multi Color Optoelectronics Co ltd
Current assignee: Hangzhou Multi Color Optoelectronics Co ltd
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2022-09-30

Abstract

The application discloses a manufacturing method of an inverted LED lamp bead, which comprises the following steps: fixing a plurality of groups of inverted LED chips on an entire support, wherein the entire support comprises a plurality of groups of supports, and each group of inverted LED chips is fixed on a corresponding support; forming a reflecting cup array by adopting an injection molding process, and bonding the reflecting cup array on the whole-plate support; manufacturing grooves on the full-page support, separating adjacent reflecting cup models by the grooves to form a plurality of reflecting cups, and extending the grooves into the support; covering a plastic packaging colloid on the full-page support, the reflecting cups and the multiple groups of flip LED chips in a mould pressing and injection molding mode, and injecting the plastic packaging colloid into the grooves to form a packaging adhesive layer; cutting the full-page support to form an inverted LED lamp bead, wherein the cutting line is positioned in the center of the groove; after the grooves are cut, a step structure of the support of the adjacent LED lamp beads is formed, and the packaging adhesive layer also covers the step structure; the inverted LED lamp bead formed after cutting comprises a reflecting cup; the juncture of support and reflection cup lateral wall is wrapped up by the encapsulation glue film, improves the leakproofness of flip-chip LED lamp pearl.

Description

Manufacturing method of flip LED lamp bead

Technical Field

The invention relates to the technical field of LEDs, in particular to a manufacturing method of an inverted LED lamp bead.

Background

The LED display screen has the following advantages: high gray scale, wide viewing angle, rich color, and customizable screen shape. Therefore, the LED display screen is widely used in various fields such as industry, traffic, commercial advertisement, information distribution, sports competition, and the like.

The pixel element used in the LED display screen is an LED lamp bead. The pixel element is, for example, an LED lamp bead in a Surface Mounted Device (SMD) package manner. With the development of LED display technology, people have higher and higher requirements for quality of display screens, and firstly, the requirements for resolution are higher and higher, which makes the dot pitch of LED display screens smaller and smaller.

Currently, the outdoor LED display screen mainly includes a lamp (direct plug-in) series and an SMD (Surface Mounted Devices) outdoor series. Because the paster product can accomplish "trinity", 3 LED chips can encapsulate inside a reflection cup promptly, can reduce the point interval between the lamp pearl to make outdoor LED display screen's definition more and more high, the display effect is more and more good, obtains extensive use. The LED lamp bead applied to the existing outdoor display screen is of a glue-pouring type packaging patch structure, an LED chip is placed on a support with a reflecting cup, and then a packaging glue layer is used for filling and sealing. Because the pins adopt a bending process, the bending angle difference exists, so that the height difference exists between the pins of the LED lamp beads, and the left and right visual angles are different; in addition, the packaging adhesive layer adopts a dispensing process, and due to the fact that the metering type dispenser fluctuates and the size of a reflecting cup of the support fluctuates, the phenomenon of uneven dispensing exists, and the phenomenon of black spots and color cast exist when the side face is viewed at a large visual angle.

In addition, the reflecting cup is made of PPA (polyphthalamide) materials, the pins of the bracket are made of metal materials, and the PPA materials and the metal materials cannot be bonded, so that gaps exist between the pins of the bracket and the reflecting cup; the surface of the lamp bead has a combined interface of the reflecting cup and the packaging adhesive layer, and when the lamp bead is used for a long time, a tiny gap can be generated due to the mismatch of expansion coefficients of different materials; therefore, water vapor can permeate into the LED lamp beads along the gaps, so that the reliability of the LED lamp beads is reduced, and the service life is shortened. And the LED chip in the existing outdoor display screen adopts a normally installed chip, 5-6 bonding wires exist in each LED lamp bead and need to be welded, the efficiency of a machine table is low, and the bonding wires are easy to lose efficacy.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide a method for manufacturing a flip-chip LED lamp bead, which improves the sealing property and weather resistance of the flip-chip LED lamp bead, improves the reliability and service life of the flip-chip LED lamp bead, and reduces the processing difficulty and cost of the flip-chip LED lamp bead.

According to one aspect of the invention, a method for manufacturing a flip LED lamp bead is provided, which comprises the following steps: fixing a plurality of groups of flip LED chips on an entire support by adopting a die bonding process, wherein the entire support comprises a plurality of groups of supports, each group of flip LED chips is fixed on a corresponding support, and each group of flip LED chips comprises at least one flip LED chip; forming a reflecting cup array by adopting an injection molding process, and bonding the reflecting cup array on a full-page support, wherein the reflecting cup array comprises a plurality of reflecting cup models, and each reflecting cup model surrounds a corresponding group of flip LED chips; manufacturing grooves on an entire support, wherein the grooves divide adjacent reflecting cup models to form a plurality of independent reflecting cups, the reflecting cups extend into the support and divide a plurality of groups of flip LED chips, and each reflecting cup surrounds a corresponding group of flip LED chips; covering plastic packaging colloid on the full-page support, the plurality of reflecting cups and the plurality of groups of flip LED chips in a mould pressing and injection molding mode, and injecting the plastic packaging colloid into the grooves to form a packaging glue layer; cutting the packaging adhesive layer and the full-page support along a cutting line to form a plurality of single inverted LED lamp beads, wherein the cutting line is located in the center of the groove; after the grooves are cut, a step structure of the support with the adjacent LED lamp beads arranged upside down is formed, and the packaging adhesive layer also covers the step structure; the inverted LED lamp bead formed after cutting comprises a reflecting cup, wherein the reflecting cup is positioned on the bracket and surrounds the at least one inverted LED chip; the juncture of the bracket and the side wall of the reflecting cup is wrapped by the packaging adhesive layer.

Preferably, the packaging glue layer is far away from the first surface of the whole plate support is formed with a plurality of convex parts with certain curvature radius, each convex part is located in a corresponding group above the flip LED chip, and after cutting, the convex parts form the lens of the single flip LED lamp bead.

Preferably, the height of the first surface of the lens is gradually decreased from the center to the periphery.

Preferably, the cross-sectional shape of the first surface of the lens is: any one of a section of arc line, a section of arc splicing curve, a section of straight line and a splicing curve of the arc.

Preferably, the top view shape of the lens comprises an oval or a circle.

Preferably, the second surface of the encapsulation adhesive layer is conformal with the surface of the imposition support, the surface of the groove, the surface of the reflection cup and the surface of the flip-chip LED chip, respectively.

Preferably, the flip LED chip includes at least one of a first LED element, a second LED element, and a third LED element.

Preferably, the flip LED chip includes three of the first LED element, the second LED element, and the third LED element.

Preferably, the first LED element, the second LED element, and the third LED element emit at least one of red light, green light, and blue light, respectively.

Preferably, the light emitting side of each of the first LED element, the second LED element, and the third LED element is a side covered by the encapsulant layer.

Preferably, the cup mouth shape of the reflecting cup of the inverted LED lamp bead comprises any one of an arc splicing pattern, a rounded rectangle, a rectangle and a circle.

Preferably, the shape of the inner wall of the reflector cup array includes any one of a rectangular, an inverted trapezoid or an arc structure.

Preferably, the array of reflector cups is black or white in color.

Preferably, when the color of the reflective cup array is black, the method further comprises: and coating a high-light-reflection material on the inner wall surface of the reflecting cup array.

Preferably, when the color of the reflective cup array is white, the method further comprises: and performing black spraying treatment on the upper surface of the reflecting cup array.

Preferably, the material of the reflector cup array is resin or plastic.

Preferably, the bracket is a double-layer circuit board, and the step of forming the bracket includes: forming a plurality of pins and a plurality of external pads on two sides of a PCB substrate respectively, wherein the pins are positioned on a first surface of the PCB substrate, and the external pads are positioned on a second surface of the PCB substrate; and forming a conductive hole penetrating through the PCB substrate, so that the pins are electrically connected with the external pads through the conductive hole between the first surface and the second surface respectively.

Preferably, the PCB substrate is an epoxy glass cloth laminate or a resin substrate.

Preferably, the encapsulation adhesive layer comprises at least one of a transparent adhesive layer and a fluorescent adhesive layer.

Preferably, the material of the encapsulation glue layer is at least one of epoxy resin, silica gel and silicone resin.

Preferably, fixing the flip LED chip on the imposition support comprises: and the flip LED chip is fixed on the full-page support through the conductive adhesive layer and is electrically connected with the full-page support.

Preferably, fixing the flip LED chip on the imposition support comprises: forming a metal electrode on the surface of the flip LED chip facing the full-page support; and fixing the metal electrode on the full-page support through eutectic welding, and electrically connecting the metal electrode with the full-page support.

Preferably, the width of the bottom of the step structure of the bracket is greater than or equal to 0.1 mm.

Preferably, the thickness of the bracket is 0.4 mm-1.0 mm.

Preferably, the height of the step structure of the bracket is one third to two thirds of the thickness of the bracket.

According to the manufacturing method of the inverted LED lamp bead, the groove is cut on the whole support to form the step structure, the step structure reduces the height of the joint of the support and the packaging adhesive layer on the side face, the joint face of the support and the packaging adhesive layer can be completely covered by waterproof adhesive, and the joint of the support and the side wall of the reflecting cup is covered by the packaging adhesive layer, so that the distance between the inverted LED chip on the contact face of the support and the packaging adhesive layer and the outside is prolonged, the distance of water vapor invading the inverted LED chip is prolonged, and the waterproof performance of the inverted LED lamp bead is improved.

Furthermore, the flip LED chip is adopted, so that the material and equipment of a bonding wire are saved, the process complexity and the cost are reduced, and the flip LED chip is good in reliability, large in light emitting area and high in brightness.

Further, through carrying out the lens design on the mould to mould plastics through the mould pressing and make the encapsulation glue film form the shape that has certain curvature radius's lens on the product surface, the encapsulation glue film multiplexing after the solidification is lens, is located flip-chip LED chip's top, both can guarantee the wide viewing angle, also can obtain higher axial light intensity luminance simultaneously, reduction consumption and cost.

Furthermore, the lens can realize light distribution forms such as floodlight, projection and condensation of the LED after refraction or reflection, effectively improve light spots, guarantee uniformity of light emission, realize light type consistency of a large visual angle, and effectively improve the problem of color cast of the large visual angle.

Furthermore, the reflection cup is designed independently, the reflection cup and the support are connected in a pressing mode through a pressing technology, light extraction efficiency is improved, and brightness is improved.

Furthermore, a PCB substrate which is similar to the packaging adhesive layer material is adopted, the PCB substrate and the packaging adhesive layer form good adhesion, or a reflection cup which is the same as or similar to the packaging adhesive layer material is formed on the PCB substrate, and the PCB substrate and the packaging adhesive layer form good adhesion through the reflection cup, so that the sealing property and the weather resistance of the outdoor flip LED lamp bead are improved, the service life of a screen is prolonged, and the cost is reduced.

Furthermore, the packaging adhesive layer is formed by adopting an injection molding process, so that a plurality of chips can be simultaneously operated, and the operation efficiency is high compared with an SMD common dispensing mode.

Furthermore, because the quantity of the lamp beads on the same area of the substrate type support is more than that of the SMD lead frames, the substrate type support can correspondingly improve the output in unit time, batch production can be realized, and the efficiency is improved.

Furthermore, the full-page support and the reflection cup array are adopted in the manufacturing process, and the packaging adhesive layer covers the full-page support and the reflection cup array, so that the integration of packaging, lenses and water resistance is realized, the batch production can be realized, and the production efficiency is improved.

Drawings

The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 shows a cross-sectional view of a flip-chip LED lamp bead for an outdoor display screen in the prior art;

fig. 2 shows a schematic structural diagram of a flip-chip LED lamp bead according to an embodiment of the present invention;

3a-3c show top views of flip-chip LED lamp beads according to embodiments of the present invention;

FIG. 4 is a schematic diagram of a prior art LED module;

FIG. 5 is a schematic structural diagram of an LED module according to an embodiment of the invention;

fig. 6a to 6e show schematic production flow diagrams of flip-chip LED lamp beads according to an embodiment of the present invention.

Detailed Description

Various embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by the same or similar reference numerals. For purposes of clarity, the various features in the drawings are not drawn to scale.

The present invention may be embodied in various forms, some examples of which are described below.

Fig. 1 shows a cross-sectional view of an LED lamp bead for an outdoor display screen in the prior art. As shown in fig. 1, the LED lamp bead 100 of the prior art includes a support 110, an LED chip 120, a packaging adhesive layer 130, and a reflective cup 140.

The LED chips 120 are uniformly disposed on the upper surface of the support 110, and the LED chips 120 are normally mounted LED chips. The bonding wires 121 electrically connect the LED chip 120 with the leads of the support 110.

The reflective cup 140 is located on the upper surface of the support 110 and is disposed around the LED chip 120.

The encapsulation adhesive layer 130 covers the upper surface of the support 110 and fills the reflective cup 140 to isolate the LED chip 120 from the outside.

In the prior art, the bending process of the pins of the support 110 causes the junction surface between the support 110 and the reflector cup 140 to be uneven. In addition, the bonding surface between the encapsulant layer 130 and the support 110 is on the upper surface of the support and inside the reflective cup 140, so that the bonding surface between the support 110 and the reflective cup 140 is not covered by the encapsulant layer 130.

Fig. 2 shows a schematic structural diagram of a flip-chip LED lamp bead provided by an embodiment of the present invention. The inverted LED lamp bead provided by the embodiment of the invention is used for an outdoor display screen, the dot spacing is larger than P2, and the size of the inverted LED lamp bead is more than 1mm x 1 mm. As shown in fig. 2, the flip-chip LED lamp bead 200 according to the embodiment of the present invention includes a support 210, at least one flip-chip LED chip 220, a packaging adhesive layer 230, and a reflective cup 240, and the flip-chip LED lamp bead is provided with a step structure 201 in an edge region of the support 210. The flip-chip LED chip 220 is located on the upper step surface (carrying surface), the packaging adhesive layer 230 covers the step structure 201 and completely covers the reflective cup 240, and the boundary between the support 210 and the sidewall of the reflective cup 240 is covered by the packaging adhesive layer 230. The position of the joint 202 of the packaging adhesive layer 230 and the support 210 is lower than the upper step surface of the support 210, so that the bearing surface of the inverted LED chip 220 on the support 210 is completely sealed, the path of water vapor invading the inverted LED chip is prolonged, and the sealing performance of the inverted LED lamp bead is improved.

Wherein, the bottom width W1 of stair structure 201 is preferred more than or equal to 0.1 millimeter, makes things convenient for the cutting processing in the manufacturing process, and the marginal portion of the encapsulation glue film of the flip-chip LED lamp pearl after the guarantee cutting extends downwards conscientiously, has prolonged the route that steam invades the flip-chip LED chip, ensures the leakproofness of flip-chip LED lamp pearl.

The flip-chip LED chip 220 is electrically connected to the support 210 through a conductive adhesive layer. Specifically, a conductive adhesive layer is disposed on the support 210, and the flip LED chip 220 is disposed on the conductive adhesive layer. The electrode of flip-chip LED chip 220 sets up at the back of the plain noodles, promptly the electrode orientation of flip-chip LED chip 220 the support 210 sets up, consequently, through set up on the support 210 the conducting resin layer, will flip-chip LED chip 220 sets up on the conducting resin layer, can make electrode on the flip-chip LED chip 220 with support 210 electric connection. Further, the conductive paste is, for example, but not limited to, one of silver paste or solder paste (solder).

In another implementation of the present embodiment, the flip-chip LED chip 220 is electrically connected to the support 210 through a eutectic soldering process. The eutectic bonding wire process does not need to adopt other conductive structures, and only needs to directly weld the electrode of the flip-chip LED chip 220 and the electrode of the bracket 210 together, so that the material and equipment of the bonding wire are saved, and the process complexity and the cost are reduced.

In this embodiment, the packaging adhesive layer 230 includes a protruding portion located above the flip LED chip 220, and the protruding portion is a lens 260 of the flip LED chip 220.

The flip-chip LED chip 220 includes at least one of a first LED element, a second LED element, and a third LED element. The first LED element, the second LED element, and the third LED element emit at least one of red light, green light, and blue light, respectively. When the flip LED chip 220 includes two or more LED elements, the arrangement order of the LED elements is not limited. Specifically, the flip LED chip 220 may be a single color, a double color, or a three-color combination of three flip LED chips of red, green, and blue, which is designed according to the functional requirements of the actual product, and is not limited herein. Therefore, the flip LED lamp bead provided by the invention can cover various display screens (full-color, double-color and single-color screens) for flip LED lamp bead design.

The encapsulant layer 230 allows light generated by the flip-chip LED chip 220 to pass through, and the material of the encapsulant layer 230 is, for example, one of epoxy, silicone, and silicone.

In a preferred embodiment, the lens 260 is integrated with the encapsulating adhesive layer 230, for example, the lens 260 may be formed on a first surface of the encapsulating adhesive layer 230 away from the support 210.

In this embodiment, a lens design is performed on a mold, the shape of the lens 260 with a certain curvature radius is formed on the surface of the product by the packaging adhesive layer 230 through mold pressing and injection molding, the packaging adhesive layer 230 is reused as a lens after being molded, and is located above the flip-chip LED chip 220, and the height of the first surface of the formed lens 260 gradually and smoothly decreases from the center to the periphery.

In a preferred embodiment, the cross-sectional shape of the first surface of the lens 260 can be selected from any one of the following: one section of arc line, a plurality of sections of arc splicing curves and a plurality of sections of straight lines and arc splicing curves. The first surface of the encapsulation adhesive layer 230 (or the lens 260) includes a curved surface located at the upper region of the flip-chip LED chip 220 and a flat surface located at the edge of the curved surface, and is disposed as a curved surface with a curvature similar to that of the curved surface at the junction of the curved surface and the flat surface to reduce the optical loss at the junction and the influence on the optical effect caused by dust accumulation, and the second surface of the lens is conformal with the surface of the support 210, the surface of the step structure 201, the surface of the reflective cup 240 and the surface of the flip-chip LED chip 220, respectively. So, encapsulation glue film 230 is multiplexing to do lens 260 makes the light distribution form that changes flip-chip LED lamp pearl after refraction or reflection of sending, thereby can play the spotlight effect and promote flip-chip LED lamp pearl luminance, reduce consumption and cost.

Referring to fig. 3a-3c, the top view shape of the lens 260 (or the curved surface formed) is circular or elliptical.

Further, the encapsulant layer 230 (or the lens 260) is formed of a high molecular polymer of a transparent material. For example, at least one selected from the group consisting of PC (polycarbonate), PPA (polyphthalamide), PCT (Poly1, 4-cyclohexene dimethyl terephthalate), silicone resin, silica gel and epoxy resin.

Further, the encapsulation adhesive layer 230 (or the lens 260) includes at least one of a transparent adhesive layer and a fluorescent adhesive layer. The flip-chip LED chip 220 is sealed on the support 210 by the packaging adhesive layer 230 (or the lens 260), and the packaging adhesive layer 230 (or the lens 260) can also prevent the flip-chip LED chip 220 from being oxidized due to water or moisture when the flip-chip LED lamp bead 200 meets with water or is affected by moisture while playing a light distribution role. Furthermore, for example, a phosphor layer is coated on the flip-chip LED chip 220, so that the phosphor layer can generate light with different colors under the excitation of different lights.

In practical applications, the encapsulant layers 230 may be selected to have different effects according to the color of the light source.

In an implementation manner of the present embodiment, the encapsulation adhesive layer 230 is, for example, a transparent adhesive layer, and the transparent adhesive layer is formed by curing a transparent adhesive. The material of the transparent glue can be, but is not limited to, one of epoxy resin, silica gel, and silicone resin. Thus, the color of the light emitted by the flip LED chip 220 does not change after passing through the transparent adhesive layer, and the flip LED lamp bead 200 can finally obtain the light with the same color as the light emitted by the flip LED chip 220.

In another implementation manner of this embodiment, the encapsulating adhesive layer 230 is, for example, a fluorescent adhesive layer, and the fluorescent adhesive layer is formed by mixing and curing fluorescent powder particles and transparent glue. The material of the transparent glue can be, but is not limited to, one of epoxy resin, silica gel, and silicone resin. Specifically, the phosphor particles may be yellow phosphor particles, red phosphor particles, green phosphor particles, or a mixture thereof. For example, the yellow phosphor particles may be composed of silicate, YAG, nitride, etc., the green phosphor may be composed of SiAlON, etc., and the red phosphor particles may be composed of nitride, silicate, KSF, KGF, etc.

Further, when the bracket 210 is soldered on a printed circuit board to be electrically conductive, or directly electrically conductive, the flip LED chip 220 can emit light. Therefore, after being refracted or reflected by the packaging adhesive layer 230 (or the lens 260), the light distribution forms of floodlight, projection, condensation and the like of the LED are realized, light spots can be effectively improved, the uniformity of light emission is ensured, and meanwhile, the visual angle of a formed light path is maximized.

The bracket 210 is a double-layer circuit board manufactured by a PCB process, and includes a PCB substrate 211, a plurality of external pads 212, and a plurality of pins 213. The plurality of pins 213 are located on the same side of the PCB substrate 211 and are respectively opposite to the plurality of external pads 212 located on the other side of the PCB substrate 211, and the plurality of pins 213 are respectively electrically connected to the corresponding plurality of external pads 212 through conductive holes in the PCB substrate 211.

The PCB substrate 211 is made of an epoxy glass fabric laminated board (FR-4) or a resin substrate (BT), and preferably has a color of white, black or gray, and the PCB substrate 211 can be better bonded with the encapsulation adhesive layer 230, so that a gap is avoided. And the outer bonding pad 212 is arranged on the back of the bracket 210, so that the waterproof glue pouring height can be reduced, and the weight of the module and the glue cost are reduced. Both sides of the PCB substrate 211 may be solder-mask coated with white oil.

The packaging adhesive layer 230 is made of an outdoor glue material such as epoxy resin and silicone resin. The glue materials and the PCB substrate material of the support can form good bonding strength, and the sealing performance of the LED lamp bead is improved.

In this embodiment, the reflective cup 240 is adhered to the support 210 by an adhesive and surrounds the at least one flip LED chip 220. The reflective cup 240 is formed by injection molding, and the material of the reflective cup 240 is an insulating material resistant to reflow soldering, such as PPA, PCT, epoxy resin.

Referring to fig. 3a-3c, the shape of the rim of the reflective cup 240 is selected from, but not limited to, any one of rounded rectangle (as shown in fig. 3 a), rectangle, circle (as shown in fig. 3 b), and arc splicing pattern (as shown in fig. 3 c). The shape of the inner wall of the reflective cup 240 is selected from any one of, but not limited to, a rectangular, an inverted trapezoid, or an arc structure.

The color of the reflective cup 240 is black or white. When the color of the reflecting cup 240 is black, the reflecting cup 240 further includes a highly reflective material on the inner wall surface of the reflecting cup, so as to achieve light condensing and reflecting effects. When the color of the reflecting cup 240 is white, the reflecting cup 240 further comprises black paint on the upper surface of the reflecting cup, so that the contrast of the product is ensured.

According to the manufacturing method of the inverted LED lamp bead, the groove is cut on the full-page support to form the step structure, the step structure reduces the height of the joint of the support and the packaging adhesive layer on the side face, the joint face of the support and the packaging adhesive layer can be completely coated by waterproof adhesive, and the joint of the support and the side wall of the reflecting cup is coated by the packaging adhesive layer, so that the distance between the inverted LED chip on the contact face of the support and the packaging adhesive layer and the outside is prolonged, the distance of water vapor invading the inverted LED chip is prolonged, and the waterproof performance of the inverted LED lamp bead is improved.

Furthermore, materials and equipment of bonding wires are saved by adopting the flip LED chip, the process complexity and the cost are reduced, and the flip LED chip has good reliability, large light-emitting area and high brightness.

Furthermore, the lens can realize light distribution forms such as floodlight, projection and condensation of the LED after refraction or reflection, effectively improve light spots, guarantee uniformity of light emission, realize light type consistency at a large visual angle, and effectively improve the color cast problem at the large visual angle.

Fig. 4 shows a schematic structural diagram of an LED module according to the prior art. As shown in fig. 4, the LED module of the prior art includes a PCB (Printed Circuit Board) 01, a plurality of LED beads 100 disposed on the PCB 01 in an array, and a waterproof layer 02.

Waterproof layer 02 can select waterproof silica gel, fills around each LED lamp pearl 100, with the common isolated bottom component of LED lamp pearl 100 of PCB board 01, also isolated steam and the contact of PCB board 01. However, in order to ensure the light emitting effect of the LED module, the waterproof layer 02 cannot shield the side surface of the LED chip, so as to ensure the light emitting effect of the side surface, that is, the thickness of the waterproof layer 02 cannot be higher than the height of the surface of the LED chip carried by the bracket, so that the joint of the reflection cup of the LED lamp bead 100 and the packaging adhesive layer cannot be covered by the waterproof layer 02, which results in poor waterproof effect of the LED lamp bead 100.

Fig. 5 shows a schematic structural diagram of an LED module according to an embodiment of the present invention. As shown in fig. 5, the LED module of the embodiment of the present invention includes a PCB 01, a waterproof layer 02, and a plurality of flip LED beads 200 distributed in an array manner, where a height of a joint 202 between a packaging adhesive layer of the flip LED bead 200 and a support is lower than a thickness of the waterproof layer 02, that is, the joint 202 between the packaging adhesive layer of the flip LED bead 200 and the support can be completely covered by the waterproof layer 02, and side light emission of the flip LED bead 200 is not affected, so that a light emission effect of the LED module can be ensured, and a waterproof effect of the flip LED bead 200 can be achieved.

The inverted LED lamp bead can achieve a better waterproof effect under the condition of maintaining the original assembly process of the LED module, and the LED module with high waterproof coefficient and suitable for the outdoors is achieved at lower cost.

Fig. 6 a-6 e show schematic flow diagrams of a manufacturing method of a flip-chip LED lamp bead according to an embodiment of the present invention.

Referring to fig. 6a, a sampling die attach process attaches a plurality of sets of flip-chip LED chips to a full-page support 10. The full-page support comprises a plurality of groups of supports, each group of flip LED chips is fixed on the corresponding support, and each group of flip LED chips comprises at least one flip LED chip 20.

Referring to fig. 6b, an injection molding process is used to form a reflective cup array, which is bonded to the imposition frame, and includes a plurality of reflective cup patterns, each of which surrounds a corresponding set of flip-chip LED chips.

Referring to fig. 6c, grooves 11 are made in the imposition of a frame that separates adjacent reflective cup molds into a plurality of individual reflective cups 40 that extend into the frame, separating groups of flip-chip LED chips, each individual reflective cup surrounding a respective group of flip-chip LED chips.

Referring to fig. 6d, a molding compound is coated on the full-page support, the plurality of reflection cups and the plurality of groups of flip LED chips by a mold pressing and injection molding method, and the molding compound is injected into the grooves to form a package glue layer 30.

In the embodiment, the whole-plate support 10 is subjected to mold-pressing injection molding packaging, a plurality of convex parts with certain curvature radius are formed on the first surface of the packaging adhesive layer away from the whole-plate support, and each convex part is positioned above a corresponding group of flip-chip LED chips. The second surface of the packaging adhesive layer is respectively conformal with the surface of the full-page support, the surface of the groove, the surface of the reflecting cup and the surface of the flip LED chip.

Referring to fig. 6e, a plurality of individual flip-chip LED lamp beads are formed after cutting the full-page support.

In this embodiment, in the cutting process, cut packaging adhesive layer 30 and full page support 10 along cutting line L, separate multiunit support to form single flip-chip LED lamp pearl. Wherein, line of cut L is located the center of slot 11, and the blade thickness of cutting usefulness will be less than slot 11's width more than 0.2 millimeter, guarantees the plastic envelope colloid thickness more than or equal to 0.1 millimeter of the stair structure department at flip-chip LED lamp pearl's support edge after the cutting to guarantee the integrity of the encapsulation glue film of this position department, ensure the leakproofness.

After the groove 11 is cut, a step structure of the support of the adjacent LED lamp bead is formed, and the packaging adhesive layer also covers the step structure; the cut flip LED lamp bead comprises a reflecting cup, the reflecting cup is positioned on the support and surrounds the at least one flip LED chip, and the junction of the support and the side wall of the reflecting cup is wrapped by the packaging adhesive layer; after cutting, the bulge forms the lens of flip LED lamp pearl, lens are located at least one flip LED chip top.

The thickness of the whole support can be selected from 0.4mm to 1.0mm, the width of the groove 11 is larger than or equal to 0.2 mm, and can be selected from 0.2 mm to 0.6 mm, and the depth can be selected from one third to two thirds of the thickness of the support, so that the mechanical strength of the support after the groove is manufactured is ensured. The whole support can be a copper-clad circuit board, and the surface of the whole support can be selected from electroplating process schemes such as gold plating, silver plating and the like.

According to the manufacturing method of the inverted LED lamp bead, the groove is formed in the full-page support to form the step structure, the step structure reduces the height of the joint of the support and the packaging adhesive layer on the side face, the joint face of the support and the packaging adhesive layer can be completely covered by waterproof adhesive, and the joint of the support and the side wall of the reflecting cup is covered by the packaging adhesive layer, so that the distance between the inverted LED chip and the outside on the contact face of the support and the packaging adhesive layer is prolonged, the distance of water vapor invading the inverted LED chip is prolonged, and the waterproof performance of the inverted LED lamp bead is improved.

The inverted LED lamp bead and the LED module can be used for an LED display screen, and the LED display screen can be an LED display screen applying the LED module, has a comprehensive waterproof effect, or only partially applies the LED module to partially prevent water according to requirements.

The flip LED lamp bead comprises a support with a step structure, at least one flip LED chip positioned on the support, a reflecting cup positioned on the support and surrounding the at least one flip LED chip, and an encapsulating adhesive layer covering the upper surface of the support, which is not covered by the flip LED chip and the reflecting cup, the step structure of the support, the reflecting cup and the flip LED chip. This stair structure has reduced the height of support and encapsulation glue film in the junction of side, makes the faying face of support and encapsulation glue film can be by the waterproof glue complete coating, and the support with the juncture of reflection cup lateral wall quilt the encapsulation glue film parcel has prolonged the distance between flip-chip LED chip and the external world on the contact surface of support and encapsulation glue film, has prolonged the distance that steam invaded flip-chip LED chip, has improved the waterproof performance of flip-chip LED lamp pearl.

The LED module comprises a PCB, a plurality of inverted LED lamp beads distributed on the PCB in an array mode and a waterproof layer filling intervals among the inverted LED lamp beads, wherein the inverted LED lamp beads are the inverted LED lamp beads provided by the invention, the position of the edge joint of the packaging adhesive layer of the inverted LED lamp beads and the support is lower than the upper surface of the waterproof layer, namely the waterproof layer can cover the joint of the packaging adhesive layer of the inverted LED lamp beads and the side edge of the support, the waterproof performance of the inverted LED lamp beads can be improved, the waterproof performance of the LED module is further improved, and the LED module can be suitable for outdoor high-humidity use environments. The manufacturing process of the packaging adhesive layer for inversely installing the LED lamp beads is die pressing injection molding, and the cost is low.

While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. The manufacturing method of the flip LED lamp bead is characterized by comprising the following steps:

fixing a plurality of groups of flip LED chips on an entire support by adopting a die bonding process, wherein the entire support comprises a plurality of groups of supports, each group of flip LED chips is fixed on a corresponding support, and each group of flip LED chips comprises at least one flip LED chip;

forming a reflecting cup array by adopting an injection molding process, and bonding the reflecting cup array on a full-page support, wherein the reflecting cup array comprises a plurality of reflecting cup models, and each reflecting cup model surrounds a corresponding group of flip LED chips;

manufacturing grooves on an entire support, wherein the grooves divide adjacent reflecting cup models to form a plurality of independent reflecting cups, the reflecting cups extend into the support and divide a plurality of groups of flip LED chips, and each reflecting cup surrounds a corresponding group of flip LED chips;

covering plastic packaging colloid on the full-page support, the plurality of reflecting cups and the plurality of groups of flip LED chips in a mould pressing and injection molding mode, and injecting the plastic packaging colloid into the grooves to form a packaging glue layer;

cutting the packaging adhesive layer and the full-page support along a cutting line to form a plurality of single inverted LED lamp beads, wherein the cutting line is located in the center of the groove;

after the grooves are cut, a step structure of the support with the adjacent LED lamp beads arranged in an inverted mode is formed, and the packaging adhesive layer covers the step structure;

the inverted LED lamp bead formed after cutting comprises a reflecting cup, wherein the reflecting cup is positioned on the bracket and surrounds the at least one inverted LED chip;

the juncture of the bracket and the side wall of the reflecting cup is wrapped by the packaging adhesive layer.

2. The method of claim 1, wherein the first surface of the encapsulant layer facing away from the monolithic support forms a plurality of bumps having a radius of curvature, each bump being located over a corresponding group of the flip-chip LED chips, and wherein after dicing the bumps form a lens for the individual flip-chip LED beads.

3. The method of claim 2, wherein the height of the first surface of the lens decreases from the center to the periphery.

4. The method of claim 2, wherein the cross-sectional shape of the first surface of the lens is: any one of a section of arc line, a section of arc splicing curve, a section of straight line and a splicing curve of the arc.

5. The method of claim 2, wherein the lens has an elliptical or circular top view shape.

6. The method of claim 1, wherein the second surface of the encapsulant layer conforms to the surface of the imposition support, the surface of the trench, the surface of the reflective cup, and the surface of the flip-chip LED chip, respectively.

7. The method of manufacturing according to claim 1, wherein the flip-chip LED chip includes at least one of a first LED element, a second LED element, and a third LED element.

8. The method of manufacturing according to claim 1, wherein the flip-chip LED chip includes three of a first LED element, a second LED element, and a third LED element.

9. The production method according to claim 7 or 8, wherein the first LED element, the second LED element, and the third LED element emit at least one of red light, green light, and blue light, respectively.

10. The manufacturing method according to claim 7 or 8, wherein the light emitting side of each of the first LED element, the second LED element, and the third LED element is the side covered by the encapsulant layer.

11. The manufacturing method of claim 1, wherein the cup mouth shape of the reflecting cup of the flip-chip LED lamp bead comprises any one of an arc splicing pattern, a rounded rectangle, a rectangle and a circle.

12. The method of claim 1, wherein the shape of the inner wall of the reflector cup comprises any one of a rectangular, an inverted trapezoidal, or an arc-shaped structure.

13. The method of claim 1, wherein the array of reflector cups is black or white in color.

14. The method of claim 13, wherein the array of reflective cups is black in color, further comprising:

and coating a high-light-reflection material on the inner wall surface of the reflecting cup array.

15. The method of claim 13, wherein when the array of reflector cups is white, further comprising:

and performing black spraying treatment on the upper surface of the reflecting cup array.

16. The method of claim 1, wherein the reflective cup array is made of a resin or plastic.

17. The method of manufacturing according to claim 1, wherein the imposition support is a double-layer circuit board, and forming the imposition support comprises:

forming a plurality of pins and a plurality of external pads on two sides of a PCB substrate respectively, wherein the pins are positioned on a first surface of the PCB substrate, and the external pads are positioned on a second surface of the PCB substrate;

and forming a conductive hole penetrating through the PCB substrate, so that the pins are electrically connected with the external pads through the conductive hole between the first surface and the second surface respectively.

18. The method of manufacturing of claim 17, wherein the PCB substrate is an epoxy glass cloth laminate or a resin substrate.

19. The method of claim 1, wherein the encapsulating adhesive layer comprises at least one of a transparent adhesive layer and a fluorescent adhesive layer.

20. The method according to claim 1, wherein the material of the encapsulating adhesive layer is at least one of epoxy resin, silicone resin and silicone resin.

21. The method of manufacturing according to claim 1, wherein the fixing the plurality of flip-chip LED chips on the imposition support comprises:

and the flip LED chip is fixed on the full-page support through the conductive adhesive layer and is electrically connected with the full-page support.

22. The method of manufacturing according to claim 1, wherein the fixing the plurality of sets of flip-chip LED chips on the imposition support comprises:

forming a metal electrode on the surface of the flip LED chip facing the full-page support;

and fixing the metal electrode on the full-page support through eutectic welding, and electrically connecting the metal electrode with the full-page support.

23. The flip-chip LED lamp bead of claim 1, wherein a bottom width of the step structure of the support is greater than or equal to 0.1 mm.

24. The flip-chip LED lamp bead of claim 1, wherein the support has a thickness of 0.4mm to 1.0 mm.

25. The flip-chip LED lamp bead of claim 1, wherein the height of the step structure of the support is one-third to two-thirds of the thickness of the support.