CN111916433B - LED display screen and preparation method thereof - Google Patents
LED display screen and preparation method thereof Download PDFInfo
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- CN111916433B CN111916433B CN201910387116.8A CN201910387116A CN111916433B CN 111916433 B CN111916433 B CN 111916433B CN 201910387116 A CN201910387116 A CN 201910387116A CN 111916433 B CN111916433 B CN 111916433B
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
- H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
- H01L25/04—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers
- H01L25/075—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00
- H01L25/0753—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes the devices not having separate containers the devices being of a type provided for in group H01L33/00 the devices being arranged next to each other
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/483—Containers
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/52—Encapsulations
- H01L33/54—Encapsulations having a particular shape
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/48—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by the semiconductor body packages
- H01L33/62—Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/30—Assembling printed circuits with electric components, e.g. with resistor
- H05K3/32—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits
- H05K3/34—Assembling printed circuits with electric components, e.g. with resistor electrically connecting electric components or wires to printed circuits by soldering
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2933/00—Details relating to devices covered by the group H01L33/00 but not provided for in its subgroups
- H01L2933/0008—Processes
- H01L2933/0033—Processes relating to semiconductor body packages
Abstract
The application relates to an LED display screen and a preparation method thereof. The preparation method of the LED display screen comprises the following steps: coating solder paste on a bare board of the printed circuit board so as to cover solder pin positions of LED lamp beads of the printed circuit board with a solder paste point layer; coating a thixotropic resin adhesive layer with a preset viscosity value at a position corresponding to the LED lamp bead on the printed circuit board; attaching the LED lamp beads to corresponding welding positions of the printed circuit board, so as to extrude the resin adhesive layer to enable the solder paste point layers in corresponding regions of the LED lamp beads to be coated with the resin adhesive layer, and enable the resin adhesive layer between the LED lamp beads and the solder paste point layers in the corresponding regions to be extruded out; and carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads. Attached in the in-process in welding position at LED lamp pearl, LED lamp pearl extrudees the resin glue film simultaneously and makes the resin glue film to diffusion all around, and the bottom and the leg of LED lamp pearl are lived in the complete cladding of resin glue film simultaneously.
Description
Technical Field
The application relates to the technical field of display equipment, in particular to an LED display screen and a preparation method thereof.
Background
An LED (Light Emitting Diode) display screen is a flat display screen composed of LED modules or LED pixel units. Because the LED display screen has the performance advantages of color, splicing, uniformity, power consumption and the like, the LED display screen is widely applied to the fields of conference places, military commands, security display, commercial display and the like.
Traditional LED display screen lamp pearl adopts GOB (Glue on Board) embedment technique to encapsulate, is about to LED lamp pearl and the whole embedments in same epoxy Glue of PCB Board front side. Due to the requirement of an application scene, the LED display screen is often used in a humid environment for a long time, water vapor enters the bottom and the inside of a lamp bead of the LED display screen through the gap of a lamp bead welding leg, firstly, the epoxy resin for packaging the LED chip can absorb water, and therefore the internal stress of the material of the LED chip is not released uniformly in high-low temperature circulation, the bent gold thread and the welding leg of the chip are broken, secondly, the circuit inside the LED display screen is short-circuited, local high temperature is generated, and even the phenomenon of breakage of the lamp bead welding leg is caused.
Disclosure of Invention
Therefore, the LED display screen and the manufacturing method thereof need to be provided to solve the problems of short circuit inside the LED display screen and breakage of the bending gold wires and the solder fillets of the chip.
A preparation method of an LED display screen comprises the following steps:
coating solder paste on the printed circuit board so as to cover a solder tail position of each LED lamp bead of the printed circuit board with a solder paste point layer;
coating a thixotropic resin adhesive layer with a preset viscosity value at a position corresponding to the LED lamp bead on the printed circuit board;
attaching the LED lamp beads to corresponding welding positions of the printed circuit board, extruding the resin adhesive layer to enable the solder paste point layers in corresponding regions of the LED lamp beads to be coated by the resin adhesive layer, and extruding the resin adhesive layer between the welding feet of the LED lamp beads and the solder paste point layers in the corresponding regions;
and carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads.
In one embodiment, the step of applying solder paste on the bare printed circuit board includes:
covering the hollow steel mesh on the bare printed circuit board;
and brushing tin paste at the hollow part of the hollow steel mesh to coat the tin paste on the printed circuit board through the hollow part preset by the hollow steel mesh.
In one embodiment, the step of brushing the solder paste on the hollow parts of the hollow steel mesh further comprises:
and removing the redundant tin paste on the surface of the hollow steel mesh, so that the quantity of the tin paste brushed at each hollow part is consistent, and the thickness of each tin paste point layer coated on the printed circuit board is consistent.
In one embodiment, the step of coating a thixotropic resin adhesive layer with a predetermined viscosity value on a corresponding position of the LED lamp bead on the printed circuit board specifically includes:
and coating a thixotropic resin adhesive layer with a preset viscosity value on the inner side of the position of the solder paste point layer corresponding to the position of the welding leg of the LED lamp bead on the printed circuit board, so that the resin adhesive layer can be simultaneously extruded to diffuse the resin adhesive layer to the periphery in the process of attaching the LED lamp bead to the printed circuit board.
In one embodiment, the step of coating a thixotropic resin adhesive layer with a predetermined viscosity value on the inner side of the position of the solder paste dot layer corresponding to the solder leg position of the LED lamp bead on the printed circuit board specifically includes:
and coating a thixotropic resin adhesive layer with a preset viscosity value in an area defined by all the solder paste point layers adjacent to the soldering leg positions of the LED lamp beads on the printed circuit board, so that the resin adhesive layer can be simultaneously extruded in the process of attaching the LED lamp beads to the printed circuit board to enable the resin adhesive layer to diffuse towards the four solder paste point layers at the soldering leg positions of the LED lamp beads.
In one embodiment, a thixotropic resin adhesive layer with a preset viscosity value is coated at the central position of a region surrounded by four solder paste point layers adjacent to the soldering feet of the LED lamp beads on the printed circuit board, so that the resin adhesive layer can be simultaneously extruded to diffuse the resin adhesive layer to the periphery in the process of attaching the LED lamp beads to the printed circuit board, the flowing speeds of the extruded resin adhesive layer towards the four solder paste point layers of the LED lamp beads are consistent, the resin adhesive layer amount of the region surrounded by the four solder paste point layers at the soldering feet of the LED lamp beads is uniform, and the required resin adhesive layer amount is less.
In one embodiment, the step of coating the thixotropic resin adhesive layer with a predetermined viscosity value on the printed circuit board specifically comprises the following steps:
and uniformly coating a thixotropic resin adhesive layer with a preset viscosity value on the printed circuit board, so that the resin adhesive layer amount of each position of the printed circuit board is uniform.
In one embodiment, the predetermined viscosity value is greater than or equal to 5000mpa.s/25 ℃, so that the resin adhesive layer has a better viscosity value, and the resin adhesive layer can be simultaneously extruded and well diffused towards the periphery in the process of attaching the LED lamp beads to the printed circuit board.
In one embodiment, a thixotropic resin glue layer with a preset viscosity value is coated on the printed circuit board by a dispensing process or a spraying process, so that the resin glue layer is coated on the printed circuit board.
The utility model provides a LED display screen, the LED display screen includes printed circuit board, LED lamp pearl, tin cream point layer and resin glue film, printed circuit board is equipped with the leg position of LED lamp pearl, tin cream point layer cover in the leg position, LED lamp pearl with tin cream point layer butt, LED lamp pearl relevant area the tin cream point layer quilt the resin glue film cladding, the resin glue film is the thixotropy resin glue through the viscosity number value of solidification more than or equal to 5000mPa.s 25 ℃.
Firstly, coating solder paste on a bare printed circuit board so as to cover solder pin positions of LED lamp beads of the printed circuit board with a solder paste point layer; then coating a thixotropic resin adhesive layer with a preset viscosity value on the printed circuit board to enable the resin adhesive layer to flow under extrusion; then attaching the LED lamp beads to corresponding welding positions of the printed circuit board, wherein in the process of attaching the LED lamp beads to the welding positions, the LED lamp beads simultaneously extrude the resin adhesive layer to enable the resin adhesive layer to diffuse around, and meanwhile, the resin adhesive layer between the LED lamp beads and the solder paste point layer in the corresponding area is extruded to flow to the periphery of the LED lamp beads, namely, the resin adhesive layer completely covers the bottoms and the welding pins of the LED lamp beads, so that the resin adhesive layer covers the solder paste point layer and cannot be retained between the LED lamp beads and the solder paste point layer of the packaged LED display screen, and the problem of insufficient welding of the lamp pins is avoided; finally, carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads to solidify the solder paste dot layer and the resin adhesive layer; after the encapsulation, because the resin glue film can not be detained between LED lamp pearl and the tin cream point layer, avoid the resin glue film to cover the lamp base department of LED lamp pearl, make the leg of LED lamp pearl totally wrapped by the resin glue film simultaneously, make the LED display screen after the encapsulation have the isolated effect of good steam, avoid steam to enter into LED lamp pearl leg and bottom, the cracked problem of the crooked gold thread and the leg of the inside circuit short circuit of LED display screen and chip has been solved, and do not influence the display effect of LED display screen itself, the radiating effect that traditional preparation method of LED display screen adopted the GOB technology to bring has also been avoided poor, the resin yellows and the difficult problem of maintaining of lamp of dying. The manufacturing method of the display screen wraps the lamp feet of the LED lamp beads and the surface of the printed circuit board, so that the bonding strength between the LED lamp beads and the printed circuit board is improved, the shock resistance of the LED lamp surface is improved, and the problem of lamp failure or lamp falling of the traditional LED display screen is effectively solved.
Drawings
FIG. 1 is a flowchart illustrating a method for manufacturing an LED display panel according to an embodiment;
FIG. 2 is a schematic diagram of step S101 of the method for manufacturing the LED display screen shown in FIG. 1;
FIG. 3 is a schematic diagram of step S103 of the method for manufacturing the LED display screen shown in FIG. 1;
FIG. 4 is a schematic diagram of step S105 of the method for manufacturing the LED display screen shown in FIG. 1;
fig. 5 is a partial schematic view of the schematic view of step S105 shown in fig. 4.
Detailed Description
In order to facilitate understanding of the present application, an LED display screen and a method for manufacturing the same will be more fully described with reference to the accompanying drawings. The preferred embodiments of the LED display screen and the preparation method thereof are shown in the attached drawings. However, the LED display and the method of making the same can be implemented in many different forms and are not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the LED display and its preparation method.
It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a single embodiment.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the LED display screen and the method of making the same is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
One embodiment is that a method for manufacturing an LED display screen includes: coating solder paste on the printed circuit board so as to cover solder pin positions of LED lamp beads of the printed circuit board with solder paste point layers; coating a thixotropic resin adhesive layer with a preset viscosity value at a position corresponding to the LED lamp bead on the printed circuit board; attaching the LED lamp beads to corresponding welding positions of the printed circuit board so as to extrude the resin adhesive layer to enable the solder paste point layers in corresponding regions of the LED lamp beads to be coated with the resin adhesive layer and enable the resin adhesive layer between the LED lamp beads and the solder paste point layers in the corresponding regions to be extruded; and carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads.
As shown in fig. 1, a method for manufacturing an LED display screen according to an embodiment includes:
step 101, coating solder paste on a Printed Circuit Board (PCB) so that a solder pad position of an LED lamp bead of the PCB is covered with a solder paste dot layer.
Specifically, referring to fig. 2, solder paste is coated on a bare board of the printed circuit board 200, so that solder pin positions of LED lamp beads of the printed circuit board are covered with a solder paste dot layer 300. In this embodiment, the number of the LED lamp beads is plural. And S101, covering a solder paste point layer on the solder leg position of each LED lamp bead. The number of the welding leg positions of each LED lamp bead of the printed circuit board is four, so that the four welding leg positions of each LED lamp bead are covered with the solder paste point layers. In one embodiment, any one of the solder paste dot layers of each LED lamp bead is cylindrical. In other embodiments, any one of the solder paste dot layers of each LED lamp bead may also be square, elliptical, or other shapes. In one embodiment, the solder paste can be a lead-containing solder paste or a lead-free solder paste.
And 103, coating a thixotropic resin adhesive layer with a preset viscosity value at a position corresponding to the LED lamp bead on the printed circuit board, so that the resin adhesive layer can flow under extrusion.
Specifically, as shown in fig. 3, a thixotropic resin adhesive layer 400 with a predetermined viscosity value is coated on a corresponding position of the LED lamp bead on the printed circuit board 200, so that the resin adhesive layer can flow when being pressed by the LED lamp bead. In one embodiment, the preset viscosity value is greater than or equal to 5000mPa.s/25 ℃, so that the resin adhesive layer has a good viscosity value, the resin adhesive layer can be simultaneously extruded and can be well diffused towards the periphery in the process of attaching the LED lamp beads to the printed circuit board, namely the resin adhesive layer has thixotropic property of pressure and does not infiltrate the PCB, and can deform and diffuse towards the periphery under the action of external force. In this example, the predetermined viscosity value is equal to 5000mpa.s/25 ℃. In other embodiments, the predetermined viscosity value may also be greater than 5000mPa.s/25 ℃, such as 8000mPa.s/25 ℃ or 10000mPa.s/25 ℃, and the like.
And 105, attaching the LED lamp beads to corresponding welding positions of the printed circuit board, extruding the resin adhesive layer to enable the solder paste point layers in corresponding areas of the LED lamp beads to be coated by the resin adhesive layer, and extruding the resin adhesive layer between the welding feet of the LED lamp beads and the solder paste point layers in the corresponding areas.
Specifically, as shown in fig. 4 and 5, the LED lamp bead 500 is attached to a corresponding welding position of the printed circuit board 200, so as to extrude the resin adhesive layer to coat the solder paste dot layer in the corresponding region of the LED lamp bead with the resin adhesive layer, and extrude the resin adhesive layer between the LED lamp bead and the solder paste dot layer in the corresponding region. Attached in welding position's in-process at LED lamp pearl, LED lamp pearl extrudees the resin glue film simultaneously and makes the resin glue film to diffusion all around, resin glue film between LED lamp pearl and the corresponding regional tin cream point layer is extruded and flows to the periphery of this LED lamp pearl simultaneously, the bottom and the leg of LED lamp pearl are lived in the complete cladding of resin glue film promptly, make resin glue film cladding tin cream point layer just can not be detained between the LED lamp pearl and the tin cream point layer of the LED display screen after the encapsulation, the problem of lamp foot rosin joint has been avoided.
In one embodiment, the LED lamp beads are attached to the corresponding welding positions of the printed circuit board through a lamp bead extrusion packaging method, so that the bottom of a chip of the LED lamp beads, lamp pins and welding pins are completely coated on the LED module by using modified epoxy resin, the contact between external water vapor and the lamp pins and the bottom of the chip of the LED lamp beads can be isolated, the bonding strength between the LED lamp beads and a PCB bottom plate can be improved, and the shock resistance can be improved to more than five times of the original shock resistance proved in a thrust test. In one embodiment, the LED lamp beads are attached to the corresponding soldering positions of the pcb by SMT (Surface Mounting Technology). Specifically, the SMT technology is adopted to paste the LED lamp beads on welding spots of the corresponding printed circuit board one by one, and the glue solution in the center of the corresponding area is extruded to spread and cover four corresponding solder paste points on the periphery. Because the resin glue is thixotropic, the resin at the contact part of the welding pin of the lamp bead and the solder paste can be extruded out, and the problem of insufficient welding of the lamp pin is avoided.
And 107, carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads to solidify the solder paste dot layer and the resin adhesive layer.
In one embodiment, before the step of coating the solder paste on the bare printed circuit board, the preparation method further comprises the steps of: and providing a PCB bare board of the LED module without being pasted with the chip and a hollow steel mesh with a corresponding model.
In one embodiment, before the step of coating the thixotropic resin adhesive layer with the predetermined viscosity value on the printed circuit board, the preparation method further comprises the following steps: providing a thixotropic resin glue.
In one embodiment, the resin bond layer includes at least one of an epoxy bond layer, a silicone bond layer, a phenolic bond layer, or an alkyd bond layer. In this embodiment, the resin adhesive layer is a single-component epoxy resin adhesive layer.
In one embodiment, the step of applying solder paste on the bare printed circuit board comprises:
and arranging the hollow steel mesh cover on the bare printed circuit board. It can be understood that for the solder paste coating requirements of different requirements, the models of the corresponding hollow steel meshes are different, for example, the sizes of the hollow parts of the hollow steel meshes are different.
The solder paste is brushed at the hollow part of the hollow steel mesh, so that the solder paste is coated on the printed circuit board through the hollow part preset by the hollow steel mesh, and the solder paste can be regularly arranged on the lamp panel according to the set patterns.
In one embodiment, the step of brushing the solder paste on the hollow part of the hollow steel mesh further comprises:
and removing the redundant tin paste on the surface of the hollow steel mesh, so that the quantity of the tin paste brushed at each hollow part is consistent, and the thickness of each tin paste point layer coated on the printed circuit board is consistent. In this embodiment, the step of coating the solder paste on the bare printed circuit board includes: covering the hollow steel mesh on the bare printed circuit board; brushing tin paste at the hollow part of the hollow steel mesh to coat the tin paste on the printed circuit board through the hollow part preset by the hollow steel mesh; and removing the redundant solder paste on the surface of the hollow steel mesh to enable the amount of the solder paste brushed at each hollow part to be consistent, so that the thickness of each solder paste point layer coated on the printed circuit board is consistent.
In one embodiment, the step of removing the excess solder paste on the surface of the hollowed steel mesh further comprises: and disassembling the hollow steel mesh to form the solder paste point layer on the printed circuit board so as to finish the demoulding operation. In this embodiment, the step of coating the solder paste on the bare printed circuit board includes: covering the hollow steel mesh on the bare printed circuit board; brushing tin paste at the hollow part of the hollow steel mesh to coat the tin paste on the printed circuit board through the hollow part preset by the hollow steel mesh; removing the redundant solder paste on the surface of the hollow steel mesh to enable the amount of the solder paste brushed at each hollow part to be consistent, and enabling the thickness of each solder paste point layer coated on the printed circuit board to be consistent; and disassembling the hollow steel mesh to form the solder paste point layer on the printed circuit board so as to finish the demoulding operation.
In one embodiment, the step of coating the thixotropic resin adhesive layer with a predetermined viscosity value on the corresponding position of the LED lamp bead on the printed circuit board specifically includes:
and coating a thixotropic resin adhesive layer with a preset viscosity value on the inner side of the position of the solder paste point layer corresponding to the position of the welding leg of the LED lamp bead on the printed circuit board, so that the resin adhesive layer can be simultaneously extruded to diffuse the resin adhesive layer to the periphery in the process of attaching the LED lamp bead to the printed circuit board.
In one embodiment, the step of coating a thixotropic resin adhesive layer with a predetermined viscosity value on the inner side of the position of the solder paste dot layer corresponding to the solder leg position of the LED lamp bead on the printed circuit board specifically includes:
and coating a thixotropic resin adhesive layer with a preset viscosity value in an area defined by all the solder paste point layers adjacent to the soldering leg positions of the LED lamp beads on the printed circuit board together, so that the resin adhesive layer can be extruded simultaneously in the process of attaching the LED lamp beads to the printed circuit board to enable the resin adhesive layer to diffuse towards each solder paste point layer direction of the soldering leg positions of the LED lamp beads. In this embodiment, the number of the solder paste dot layers at the solder tail positions of the LED lamp beads is four. Specifically, a thixotropic resin adhesive layer with a preset viscosity value is coated at the position of an area surrounded by four tin paste point layers adjacent to the solder leg position of the LED lamp bead on the printed circuit board.
As shown in fig. 3, in one embodiment, a thixotropic resin adhesive layer 400 with a predetermined viscosity value is coated at a central position of a region surrounded by four solder paste dot layers 300 adjacent to the solder tail positions of the LED lamp beads on the printed circuit board 200, so that not only the resin adhesive layer can be simultaneously pressed to diffuse the resin adhesive layer to the periphery in the process of attaching the LED lamp beads to the printed circuit board, but also the flow speed of the pressed resin adhesive layer toward the four solder paste dot layers of the LED lamp beads is consistent, the resin adhesive layer amount of the region surrounded by the four solder paste dot layers at the solder tail positions of the LED lamp beads is relatively uniform, and the required resin adhesive layer amount is relatively small.
In one embodiment, a thixotropic resin adhesive layer with a preset viscosity value is coated at the central position of a region surrounded by four tin paste point layers adjacent to the welding foot position of an LED lamp bead on a printed circuit board by adopting a dispensing process. Specifically, a thixotropic resin adhesive layer with a preset viscosity value point by point is arranged at the central position of a region surrounded by four tin paste point layers close to the soldering leg positions of the LED lamp beads on the printed circuit board through a target-hitting type dispenser. In one embodiment, the single-point glue dispensing amount of the welding leg position of the LED lamp bead is 0.5-2 mg.
In one embodiment, the step of coating the thixotropic resin adhesive layer with a predetermined viscosity value on the printed circuit board specifically comprises the following steps:
the thixotropic resin glue layer with the preset viscosity value is uniformly coated on the printed circuit board, so that the resin glue layer amount of each position of the printed circuit board is uniform.
In one embodiment, a thixotropic resin adhesive layer with a predetermined viscosity value is coated on the printed circuit board by a dispensing process or a spraying process, so that the resin adhesive layer is coated on the printed circuit board. In the embodiment, a dispensing process is adopted to perform dispensing on the thixotropic resin adhesive layer with a preset viscosity value point by point in the center of the area surrounded by the four welding positions corresponding to any LED lamp bead of the printed circuit board, so that the resin adhesive layer is coated on the printed circuit board, and meanwhile, the glue amount corresponding to the resin adhesive layer can be saved. Specifically, a thixotropic resin adhesive layer with a preset viscosity value point by point is arranged at the center of a region surrounded by four welding positions corresponding to any LED lamp bead of the printed circuit board through a target-type dispenser.
It can be understood that in other embodiments, the thixotropic resin adhesive layer is not limited to a thixotropic resin adhesive layer with a predetermined viscosity value point by point in the center of an area surrounded by four welding positions corresponding to any LED lamp bead of the printed circuit board by using a dispensing process. In one embodiment, a thixotropic resin paste layer of a predetermined viscosity value is sprayed on the printed wiring board using a spraying process. In this embodiment, a thixotropic resin adhesive layer with a predetermined viscosity value is uniformly sprayed on the printed circuit board by a spraying process. Specifically, an ink jet device is used to uniformly spray a thixotropic resin glue layer with a predetermined viscosity value on the printed circuit board. In one embodiment, the spraying thickness is 0.1 mm-1 mm to ensure that the thickness of the resin adhesive layer is higher than the height of the lamp base of any LED lamp bead.
In one embodiment, the thickness of the resin adhesive layer is larger than the thickness of the welding pin position of the LED lamp bead, and the thickness of the resin adhesive layer is higher than the height of the lamp pin of the LED lamp bead.
The following are specific examples that will further explain the present application in detail. It should be understood that the specific embodiments described herein are merely illustrative of the present application and do not delimit the scope of the present application.
Detailed description of the preferred embodiment 1
Firstly, a PCB bare board and a hollow steel mesh of the LED module are provided. In the present embodiment, the model number of the LED module is P2.5.
And then, covering the hollow steel mesh on the PCB bare board.
And then, brushing lead-free tin paste at the hollow part, so that the tin paste can be regularly arranged on the lamp panel according to a set pattern.
And then, removing the redundant solder paste after the coating process is finished, and demolding to form a solder paste point layer corresponding to any LED lamp bead on the PCB bare board.
Then, taking the single-component thixotropic epoxy resin glue. The viscosity value of the resin glue is 10000mPa.s/25 ℃, the resin glue has non-wetting property and pressure thixotropic property, and can deform and diffuse to the periphery under the action of external force.
And then, dispensing one by one at the center of an area surrounded by four welding foot positions corresponding to each LED lamp bead by using a target-type dispenser. In one embodiment, the amount of single-point dispensing at any one fillet position is 1mg to 3 mg. Specifically, in this embodiment, the single-point dispensing amount at any fillet position is 1 mg. In one embodiment, the dispensing speed is 20 dot/s-50 dot/s, so that the preparation efficiency of the LED display screen is high, and the dispensing quality of any welding leg position is good. In the present embodiment, the dispensing speed is 30 dot/s.
And then, attaching the LED lamp beads to the welding points of the corresponding PCB one by adopting an SMT (surface mount technology), and extruding the glue solution in the center of the corresponding area to spread the glue solution and cover four corresponding solder paste points on the periphery. Because the resin glue is thixotropic, the resin at the contact part of the welding pin of the lamp bead and the solder paste can be extruded out, and the problem of insufficient welding of the lamp pin is avoided.
And finally, carrying out normal reflow soldering treatment on the LED module of the SMT patch, so that the solder paste and the resin are cured at normal high temperature. Through the thrust test, the upper limit of the thrust of the LED module lamp without dispensing encapsulation is 0.9 kg-1.2 kg, and the upper limit of the thrust of the LED module lamp encapsulated by the application is 4 kg-5 kg, so that the shock resistance of the LED module is improved by about five times on the original basis.
Specific example 2
Firstly, a PCB bare board and a hollow steel mesh of the LED module are provided. In the present embodiment, the model number of the LED module is P1.2.
And then, covering the hollow steel mesh on the PCB bare board.
And then, brushing lead-free solder paste at the hollow part, so that the solder paste can be regularly arranged on the lamp panel according to a set pattern.
And then, removing redundant solder paste and demoulding after the coating process is finished so as to form a solder paste point layer corresponding to any LED lamp bead on the PCB bare board.
Then, taking the single-component thixotropic epoxy resin glue. The viscosity value of the resin glue is 5000mPa.s/25 ℃, the resin glue has the performance of not infiltrating a PCB (printed Circuit Board) and pressure thixotropic performance, and can deform and diffuse to the periphery under the action of external force.
And then, spraying a uniform resin adhesive layer on the PCB by adopting an ink jet device. In this embodiment, the thickness of the glue layer is 0.3 mm.
And then, attaching the LED lamp beads on the welding spots of the corresponding PCB one by adopting an SMT (surface mount technology). Because resin glue is thixotropic, the resin of the contact part of the lamp pin and the solder paste is extruded by the extrusion of the surfaces of the lamp pin and the solder paste, the bottom of the lamp bead and the solder pin can be completely coated by the resin layer, and meanwhile, the problem of insufficient soldering of the lamp pin is avoided.
And finally, carrying out normal reflow soldering treatment on the LED module of the SMT paster, so that the solder paste and the resin are normally cured at high temperature. Through the thrust test, the upper limit of the thrust of the LED module lamp without dispensing encapsulation is 0.9 kg-1.2 kg, the upper limit of the thrust of the LED module lamp encapsulated by the LED module is 10kg, and the shock resistance is improved by about ten times on the original basis.
The application also provides an LED display screen which is prepared by the preparation method of the LED display screen of any embodiment. As shown in fig. 4 and 5, in one embodiment, the LED display screen 10 includes a printed circuit board 200, LED beads 500, a solder paste dot layer 300, and a resin adhesive layer 400. The printed circuit board is provided with the welding leg position of the LED lamp bead. The solder paste point layer covers the solder leg position, and the LED lamp bead is abutted to the solder paste point layer. And the solder paste point layer in the corresponding area of the LED lamp bead is coated by the resin adhesive layer. The resin adhesive layer is a cured thixotropic resin adhesive with the viscosity value of more than or equal to 5000mPa.s/25 ℃.
Firstly, coating solder paste on a bare printed circuit board so as to cover solder pin positions of LED lamp beads of the printed circuit board with a solder paste point layer; then coating a thixotropic resin adhesive layer with a preset viscosity value on the printed circuit board to enable the resin adhesive layer to flow under extrusion; then attaching the LED lamp beads to corresponding welding positions of the printed circuit board, wherein in the process of attaching the LED lamp beads to the welding positions, the LED lamp beads simultaneously extrude the resin adhesive layer to enable the resin adhesive layer to diffuse around, and meanwhile, the resin adhesive layer between the LED lamp beads and the solder paste point layer in the corresponding area is extruded to flow to the periphery of the LED lamp beads, namely, the resin adhesive layer completely covers the bottoms and the welding pins of the LED lamp beads, so that the resin adhesive layer covers the solder paste point layer and cannot be retained between the LED lamp beads and the solder paste point layer of the packaged LED display screen, and the problem of insufficient welding of the lamp pins is avoided; finally, carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads to solidify the solder paste point layer and the resin adhesive layer; after the encapsulation, because the resin glue film can not be detained between LED lamp pearl and the tin cream point layer, avoid the resin glue film to cover the lamp base department of LED lamp pearl, make the leg of LED lamp pearl totally wrapped by the resin glue film simultaneously, make the LED display screen after the encapsulation have the isolated effect of good steam, avoid steam to enter into LED lamp pearl leg and bottom, the problem that the crooked gold thread and the leg of the inside circuit short circuit of LED display screen and chip produced the fracture has been solved, and do not influence the display effect of LED display screen itself, the radiating effect that traditional preparation method of LED display screen adopted the GOB technology to bring has also been avoided poor, the resin shines yellow and the difficult problem of maintaining of lamp of dying. The manufacturing method of the display screen wraps the lamp feet of the LED lamp beads and the surface of the printed circuit board, so that the bonding strength between the LED lamp beads and the printed circuit board is improved, the shock resistance of the LED lamp surface is improved, and the problem of lamp failure or lamp falling of the traditional LED display screen is effectively solved.
All possible combinations of the technical features of the above embodiments may not be described for the sake of brevity, but should be considered as within the scope of the present disclosure as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several implementation modes of the present application, and the description thereof is specific and detailed, but not construed as limiting the scope of the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.
Claims (10)
1. A preparation method of an LED display screen is characterized by comprising the following steps:
coating solder paste on the printed circuit board so as to cover solder pin positions of LED lamp beads of the printed circuit board with solder paste point layers;
coating a thixotropic resin adhesive layer with a preset viscosity value on the inner side of the position of the solder paste point layer corresponding to the soldering leg position of the LED lamp bead on the printed circuit board;
attaching the LED lamp beads to corresponding welding positions of the printed circuit board, extruding the resin adhesive layer to enable the solder paste point layers in corresponding regions of the LED lamp beads to be coated by the resin adhesive layer, and extruding the resin adhesive layer between the soldering feet of the LED lamp beads and the solder paste point layers in the corresponding regions;
and carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads.
2. The method for manufacturing the LED display screen according to claim 1, wherein the step of coating the solder paste on the bare printed circuit board comprises:
covering the hollow steel mesh on the bare printed circuit board;
and brushing tin paste at the hollow part of the hollow steel mesh.
3. The method for manufacturing the LED display screen according to claim 2, wherein the step of brushing the solder paste on the hollow parts of the hollow steel mesh further comprises the following steps:
and removing the redundant solder paste on the surface of the hollowed-out steel mesh.
4. The method for manufacturing the LED display screen according to claim 1, wherein the step of coating the thixotropic resin glue layer with a preset viscosity value on the inner side of the position of the solder paste point layer corresponding to the solder leg position of the LED lamp bead on the printed circuit board specifically comprises the following steps:
and coating a thixotropic resin adhesive layer with a preset viscosity value in an area defined by all the solder paste point layers adjacent to the soldering leg positions of the LED lamp beads on the printed circuit board.
5. The method for manufacturing the LED display screen according to claim 1, wherein a thixotropic resin glue layer with a preset viscosity value is coated at the center of a region surrounded by four solder paste point layers adjacent to the solder leg positions of the LED lamp beads on the printed circuit board.
6. The method for manufacturing an LED display screen according to claim 1, wherein the predetermined viscosity value is greater than or equal to 5000mPa.s/25 ℃.
7. The method for manufacturing the LED display screen according to claim 1, wherein the resin adhesive layer comprises at least one of an epoxy resin adhesive layer, a silicone resin adhesive layer, a phenolic resin adhesive layer or an alkyd resin layer.
8. A preparation method of an LED display screen is characterized by comprising the following steps:
coating solder paste on the printed circuit board so as to cover solder pin positions of LED lamp beads of the printed circuit board with solder paste point layers;
uniformly coating a thixotropic resin adhesive layer with a preset viscosity value on the printed circuit board;
attaching the LED lamp beads to corresponding welding positions of the printed circuit board, extruding the resin adhesive layer to enable the solder paste point layers in corresponding regions of the LED lamp beads to be coated by the resin adhesive layer, and extruding the resin adhesive layer between the welding feet of the LED lamp beads and the solder paste point layers in the corresponding regions;
and carrying out reflow soldering treatment on the printed circuit board attached with the LED lamp beads.
9. The method for manufacturing the LED display screen according to any one of claims 1 to 8, wherein the thixotropic resin glue layer with a predetermined viscosity value is coated on the printed circuit board by a glue dispensing process or a spraying process.
10. The LED display screen obtained by the method for preparing the LED display screen according to any one of claims 1 to 9, wherein the LED display screen comprises a printed circuit board, LED lamp beads, a solder paste dot layer and a resin adhesive layer, the printed circuit board is provided with solder foot positions of the LED lamp beads, the solder paste dot layer covers the solder foot positions, the LED lamp beads are abutted to the solder paste dot layer, the solder paste dot layer in corresponding areas of the LED lamp beads is coated by the resin adhesive layer, and the resin adhesive layer is a cured thixotropic resin adhesive with a viscosity value greater than or equal to 5000mPa.s/25 ℃.
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| CN114828401A (en) * | 2022-04-08 | 2022-07-29 | 百为智能科技(广州)有限公司 | Lamp bead circuit preparation method based on large-size hollow glass substrate and display device |
| CN117320311A (en) * | 2022-06-21 | 2023-12-29 | 西安青松光电技术有限公司 | Dispensing method of lamp beads in LED lamp panel and LED display screen |
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