Mini LED packaging process for integrated multi-module spliced screen

Abstract

The invention relates to the technical field of LED packaging, and particularly discloses a Mini LED packaging process of an integrated multi-module spliced screen. Comprising the following steps: (1) carrying out underfilling on the front surface of a lamp panel of a single Mini LED lamp panel module by using a first adhesive layer; (2) carrying out UV curing or thermocuring on the first adhesive layer after underfilling of the lamp panel module; (3) according to a preset screen splicing array, the alignment edges, located at the joints of the adjacent modules, of all the lamp panel modules and the adhesive films covering the alignment edges are integrally cut, and process edges are reserved; (4) mounting the plurality of lamp panel modules subjected to the first cutting treatment in a box body or a jig according to a preset spliced screen array, and adjusting the flatness between the modules; (5) integrally covering the front surface of the lamp panel array with a second adhesive film; (6) carrying out UV curing or thermocuring on the whole lamp panel array subjected to film pasting; and (7) integrally cutting the process edge and the adhesive film covering the process edge to obtain the integrated multi-module spliced screen display unit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of LED packaging, and specifically discloses a Mini LED packaging process of an integrated multi-module spliced screen. BACKGROUND

[0002] The chip size is usually between 50-200 microns, which is much smaller than that of ordinary LEDs, so more chips can be integrated in a unit area to achieve higher pixel density and finer light control capability. The Mini LED production line is also called the packaging line. Packaging is a key step in Mini LED production. Without a good packaging process, good Mini LED components cannot be produced. The packaging of Mini LED not only ensures the service life of the PCB board, but also enhances the appearance consistency of Mini LED. Mini LED packaging requires higher precision and consistency, involving mass transfer, micro-pitch welding, high-precision dispensing, and other processes, which require extremely high equipment and materials. In the entire Mini LED packaging production process, film pasting and cutting are key steps that determine the effect of the entire packaging. The existing Mini LED packaging process has the following defects: the appearance color difference and gap of the screen interface panel and the board normal angle, left and right angle of the finished product after splicing exist due to the height difference.

[0003] In the existing Mini LED packaging production process, the film pasting step is: film pasting → bubble removal → detection → curing → cutting → grading → screen splicing.

[0004] Film pasting: the packaging film is pasted on the PCB board under specific temperature / pressure / time parameters;

[0005] Bubble removal: the PCB board after film pasting is placed under high temperature / high pressure / time conditions to remove the bubbles in the film material glue layer;

[0006] Detection: check whether the lamp panel has dead lamps, dark and bright, and appearance defects;

[0007] Curing: the lamp panel after bubble removal is cured by UV curing or high temperature curing of the film material;

[0008] Cutting: using cutting tools to remove the process edge of the lamp panel;

[0009] Grading: using test instruments / equipment to sort the lamp panel by color;

[0010] Screen splicing: arranging and splicing the single module on the lamp panel box according to the color sequence or manually multiple times.

[0011] In the existing process, the single PCB board in the film pasting process has the following problems: thickness difference between the boards, poor tin fusion effect, chip height difference, and inconsistent base color, etc., which cause the finished product module to have appearance color difference.Fig. 1-2 Therefore, before screen splicing, the device or manual grading screening needs to be used, which seriously affects the work efficiency and cannot actually solve the ink color difference problem. SUMMARY

[0012] The present application aims to overcome the deficiencies of the prior art and provide a Mini LED packaging process for integrated multi-module screen splicing.

[0013] The present application discloses a Mini LED packaging process for integrated multi-module screen splicing, which adopts the following technical solutions:

[0014] A Mini LED packaging process for integrated multi-module screen splicing includes the following steps:

[0015] (1) Bottom filling: The single Mini LED lamp panel module is bottom filled with a first adhesive layer on the front of the lamp panel, so that the first adhesive layer covers the LED chip and the circuit;

[0016] (2) First solidification: The first adhesive layer of the lamp panel module after bottom filling is UV cured or heat cured to form a first packaging layer;

[0017] (3) First cutting: According to the preset screen splicing array, the alignment edges of each lamp panel module located at the joint between adjacent modules are integrally cut together with the adhesive film covering thereon, and a process edge is reserved;

[0018] (4) Screen splicing: Multiple lamp panel modules after the first cutting are installed in a box or jig according to the preset screen splicing array to form a lamp panel array, and the flatness between the modules is adjusted;

[0019] (5) Integrated film pasting: The second adhesive film is integrally covered on the front of the lamp panel array, and the second adhesive film is bonded with the first adhesive layer by pressing;

[0020] (6) Second solidification: The lamp panel array after film pasting is integrally UV cured or heat cured to form an integrated packaging structure of the first adhesive layer and the second adhesive film;

[0021] (7) Second cutting: The process edge together with the adhesive film covering thereon is integrally cut to obtain an integrated multi-module screen display unit.

[0022] Preferably, the process edge is used for positioning the lamp panel module in the cutting and screen splicing steps.

[0023] Preferably, the first adhesive layer is a semi-solid adhesive, which is covered on the whole panel module by pressing.

[0024] Preferably, a vacuum defoaming step is added after step (1) and before step (2), and the underfilling and vacuum defoaming are performed by a film sticking device which is capable of vacuumizing the first adhesive film after pressing to remove the air bubbles between the film and the lamp panel module.

[0025] Preferably, the first adhesive layer is a liquid adhesive which is applied on the whole panel module by spraying.

[0026] Preferably, a vacuum defoaming step is added after step (5) and before step (6).

[0027] Preferably, the second adhesive film is a composite film of a semi-solid adhesive and a protective film, and the protective film is on the top of the LED module.

[0028] Preferably, the first adhesive film is a UV adhesive, an EVA adhesive or an OCA adhesive, and the second adhesive film is a composite film of an EVA adhesive or an OCA adhesive and a PET film.

[0029] Preferably, the box or jig is provided with positioning pins for positioning with the process edge during the screen assembling step.

[0030] Preferably, the width of the process edge is 1-10 mm.

[0031] Compared with the prior art, the present application has at least the following beneficial effects:

[0032] The present application provides a Mini LED packaging process for integrated multi-module screen assembling, which overturns the traditional "cutting first and then sealing" logic. The single lamp panel is first underfilled and solidified to form a complete protective surface, and then cut along the contour to leave a process edge, so that the Mini LED chip is free from mechanical damage throughout the process. At the same time, the process edge becomes a positioning reference for screen assembling, greatly improving the assembly precision. After the multi-panel screen assembling is completed, the optical adhesive film is covered on the whole panel for final sealing, which completely eliminates the color deviation caused by the differences in panel thickness, uneven tin fusion, chip height difference and inconsistent base color. The segmented packaging not only reduces the risk of single panel damage, but also realizes efficient film sticking of the whole panel through the "reservation-integration" strategy, significantly shortens the production cycle, and balances high yield, low cost and colorless display. It provides a reliable process path for high-density production of Mini LED. BRIEF DESCRIPTION OF DRAWINGS

[0033] Fig. 1 It is a schematic diagram of the LED packaging layer of the prior art;

[0034] Fig. 2 It is a schematic diagram of the LED packaging effect of the prior art;

[0035] Fig. 3 It is a schematic diagram of the module before underfilling of the Mini LED packaging process for integrated multi-module screen assembling of the present application;

[0036] Fig. 4 A module schematic diagram after the bottom filling and curing of the Mini LED packaging process of the integrated multi-module spliced screen of the present application;

[0037] Fig. 5 A first cutting mark schematic diagram of the Mini LED packaging process of the integrated multi-module spliced screen of the present application;

[0038] Fig. 6 A module schematic diagram after the first cutting of the Mini LED packaging process of the integrated multi-module spliced screen of the present application;

[0039] Fig. 7 A module schematic diagram after the integrated film pasting of the Mini LED packaging process of the integrated multi-module spliced screen of the present application;

[0040] Fig. 8 A second cutting mark schematic diagram of the Mini LED packaging process of the integrated multi-module spliced screen of the present application;

[0041] Fig. 9 A module schematic diagram after the second cutting of the Mini LED packaging process of the integrated multi-module spliced screen of the present application;

[0042] Fig. 10 A LED packaging layer schematic diagram of the Mini LED packaging process of the integrated multi-module spliced screen of the present application. DETAILED DESCRIPTION

[0043] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below in combination with the drawings and specific embodiments.

[0044] Embodiment 1

[0045] The present embodiment discloses a Mini LED packaging process of an integrated multi-module spliced screen, which comprises the following steps:

[0046] (1) Bottom filling: select a 1*8pcs box module lamp panel, the PCB board is 180mm long*170mm wide, and each PCB board is randomly arranged (as shown in Figure 3), and the single Mini LED lamp panel module is bottom filled with a first glue layer on the front of the lamp panel, so that the first glue layer covers the LED chip and the circuit; the first glue layer is a semi-solid glue (specifically OCA glue), which can be bottom filled and vacuum degassed by using a film pasting device, the hot pressing temperature of the film pasting device is 70-100℃, the pressure is 30-50kg / cm2, the time is 1-5min, and the film pasting device is vacuumed after hot pressing to remove bubbles between the lamp panel module; the first glue layer is pressed and covered on the whole panel module, which protects the appearance of the PCB lamp panel and covers the PCB board color;

[0047] (2) First curing: heat curing the first glue layer after the bottom filling of the lamp panel module, temperature 90-100°C, time 5-10 min, so that the first glue layer and the PCB board are tightly packaged together to form a first packaging layer. The effect after the glue is attached and cured is shown in Figure 4;

[0048] (3) First cutting: according to the preset screen array, the alignment edges of the lamp panel module located at the joint of adjacent modules are integrally cut together with the glue film covering thereon, and the process edges for subsequent positioning are reserved. The single PCB board is fixed using a jig, and the process edges of the PCB edge are cut using a cutting machine. The 1# / 2# / 7# / 8# PCB board is cut with 2 process edges, and the 3# / 4# / 5# / 6# PCB board is cut with 3 process edges. The yellow area is the cutting area, and the other areas are not cut (as shown in Figure 5 and Table 1).

[0049] Table 1

[0050]

[0051] (4) Screen assembly: 8pcs lamp panel modules after the first cutting are installed in the box or jig according to the preset screen array to form a lamp panel array. The 8pcs cut and spliced process edge PCB boards are assembled on the box / jig. The box or jig is provided with positioning pins. The reserved process edges cooperate with the positioning pins to achieve accurate positioning. The flatness between the modules is adjusted and fixed (as shown in Figure 6).

[0052] (5) Integrated film attachment: remove the release protective film on the upper surface of the 8pcs modules, and integrally cover a second glue film with a length of 650mm and a width of 350mm on the front surface of the lamp panel array. The second glue film is bonded with the first glue layer by heat pressing. The second glue film is a composite film of semi-solid glue and protective film (the semi-solid glue can be OCA glue, and the protective film can be PET film).

[0053] (6) Second curing: heat curing the lamp panel array after the film is attached, temperature 90-100°C, time 5-10 min, so that the first glue layer and the second glue film are bonded together to form an integrated packaging structure (as shown in Figure 7). The second glue film is on the top of the LED module and plays a role in surface consistency.

[0054] (7) Second cutting: integrally cutting the process edges marked in yellow together with the glue film covering thereon (as shown in Figure 8 and Table 2), to obtain an integrated multi-module screen display unit. After inspection, the size is qualified, and the screen is aged, packaged and stored (as shown in Figure 9). Fig. 10 The figure is a schematic diagram of the Mini LED packaging layer of the present scheme. The bottom filling glue in the figure is the first glue layer, and the optical glue and optical film are the second glue film.

[0055] Table 2

[0056]

[0057] Example 2

[0058] This embodiment discloses an integrated multi-module splicing Mini LED packaging process. Unlike Embodiment 1, the underfill uses liquid adhesive, and the degassing step is moved to before the second curing step. Specifically, it includes the following steps:

[0059] (1) Underfilling: The first adhesive layer is used to underfill the front of the single Mini LED lamp board module, so that the first adhesive layer covers the LED chip and circuit; the first adhesive layer is liquid adhesive (specifically, it can be UV adhesive). Liquid adhesive is fast, has good leveling properties, cures quickly and has good consistency during the underfilling process. It is sprayed onto the entire board module to form lamp surface protection.

[0060] (2) First curing: UV curing of the first adhesive layer after the base filler of the lamp panel module, with a UV energy of 3000-5000 mJ / cm. 2 The first encapsulation layer is formed in 3-5 seconds.

[0061] (3) First cut: According to the preset splicing array, the alignment edge of each light panel module located at the joint of adjacent modules, together with the adhesive film covering it, is cut as a whole, and the process edge for subsequent positioning is reserved.

[0062] (4) Splicing: Multiple light panel modules that have undergone the first cutting process are installed in the box or fixture according to the preset splicing array to form a light panel array. The flatness between the modules is adjusted. The box or fixture is equipped with positioning pins. The reserved process edge cooperates with the positioning pins to achieve precise positioning.

[0063] (5) Integrated film application: The second adhesive film is applied to the entire front of the light panel array. The second adhesive film is bonded to the first adhesive layer by hot pressing. The hot pressing temperature is 70-100℃, the pressure is 30-50kg / cm2, and the time is 1-5min. The second adhesive film is a composite film of semi-solid adhesive and protective film (the semi-solid adhesive can be OCA adhesive, and the protective film can be PET film). The second adhesive film is vacuumed to remove air bubbles. The degassing vacuum degree is -75 to -85kPa, and the degassing time is 30-180s.

[0064] (6) Second curing: UV curing is performed on the entire lamp panel array after film application, with a UV energy of 3000-5000 mJ / cm². 2 The time is 3 to 5 seconds, which allows the first adhesive layer and the second adhesive film to adhere and form an integrated encapsulation structure. The protective film of the second adhesive film is on the top of the LED module, which serves to ensure surface consistency.

[0065] (7) Second cutting: The process edge along with the adhesive film covering it is cut as a whole to obtain an integrated multi-module splicing display unit.

[0066] The following is an analysis of the two mainstream LED packaging processes:

[0067] The existing LED packaging process flow 1 (e.g., patent CN 110808244 A) is: glue preparation → preheating → degassing → potting → lamination → pressing → curing → setting → cutting. In this process, the potting stage requires high-precision special molds, which are costly, require frequent maintenance and replacement, have a long production cycle, poor consistency, and, after panelization, issues such as thickness differences, poor soldering effects, chip height differences, and inconsistent background colors between boards result in color differences in the finished modules.

[0068] The existing LED packaging process flow 2 (e.g., patent CN 112635625 A) is: cutting → splicing → adhesive application → film application → hot pressing → baking → blowing → debubbling → curing. During the manufacturing process, the LED board surface is unprotected during cutting and splicing, making it susceptible to damage; and there are no process edges around the edges during film application, leading to peeling or misalignment of the LED film at the edges.

[0069] Mini LEDs have extremely high requirements for surface flatness, packaging consistency, and chip protection, and the traditional processes mentioned above are difficult to meet their packaging accuracy and yield requirements.

[0070] Unlike traditional LED packaging processes, the Mini LED packaging process in this solution is as follows:

[0071] The specific process steps are: bottom filling → degassing → curing 1 → cutting 1 → splicing → film application → hot pressing → curing 2 → cutting 2.

[0072] The specific process involves two steps: base filling → curing 1 → cutting 1 → screen splicing → film application → hot pressing → degassing → curing 2 → cutting 2.

[0073] The core innovation of this solution lies in its three-pronged approach of "segmented packaging + process edge reservation + integrated film application across the entire board," which completely changes the traditional LED packaging process of "cutting first, then packaging, and then splicing."

[0074] Underfill first, then cut: Underfilling and encapsulation are completed at the individual lamp board stage to form a complete protective surface, avoiding mechanical damage or contamination to the MiniLED chip during subsequent handling, cutting, and splicing.

[0075] Cutting with edge protection and precise positioning: The process edge is preserved during cutting, which not only provides a high-precision positioning benchmark for subsequent splicing, but also avoids problems such as film material warping and offset caused by the traditional "no protective edge", which significantly improves splicing accuracy and yield.

[0076] Final sealing after panel splicing: The optical film encapsulation is performed uniformly after the panel splicing is completed, so as to achieve one-time film application and curing of the whole board. This completely eliminates the ink color difference caused by differences in thickness between boards, differences in solder fusion, differences in chip height, and inconsistencies in background color, and fundamentally solves the color difference problem.

[0077] Integrated operation, doubled efficiency: whole-panel film application replaces traditional single-panel multiple film application, reducing equipment and fixture costs to about 200 yuan, shortening the production cycle to 8 hours, taking into account high efficiency, low cost, and high consistency, perfectly meeting the mass production requirements of Mini LED high density, micro-pitch, and high color consistency.

[0078] The technical solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A Mini LED packaging process for integrated multi-module splicing screens, characterized in that, Includes the following steps: (1) Underfilling: The first adhesive layer is used to fill the front of the single Mini LED light board module, so that the first adhesive layer covers the LED chip and circuit. (2) First curing: UV curing or heat curing is performed on the first adhesive layer after the bottom filling of the lamp panel module to form the first encapsulation layer; (3) First cut: According to the preset splicing array, the alignment edge of each light panel module located at the joint of adjacent modules, together with the adhesive film covering it, is cut as a whole, and the process edge is retained. (4) Panel splicing: Install multiple light panel modules that have undergone the first cutting process into a preset panel splicing array in a box or fixture to form a light panel array, and adjust the flatness between the modules; (5) Integrated film application: The second adhesive film is completely covered on the front of the light panel array, and the second adhesive film is bonded to the first adhesive layer by pressing. (6) Second curing: UV curing or heat curing is performed on the entire lamp panel array after film application to form an integrated encapsulation structure between the first adhesive layer and the second adhesive film. (7) Second cutting: The process edge along with the adhesive film covering it is cut as a whole to obtain an integrated multi-module splicing display unit.

2. The Mini LED packaging process for integrated multi-module splicing screens according to claim 1, characterized in that, The process edge is used for positioning the light panel module in the cutting and splicing steps.

3. The Mini LED packaging process for integrated multi-module splicing screens according to claim 1, characterized in that, The first adhesive layer is a semi-solid adhesive, which is applied to the entire module by pressing.

4. The Mini LED packaging process for integrated multi-module splicing screens according to claim 3, characterized in that, A vacuum degassing step is added after step (1) and before step (2). A film-applying device is used for bottom filling and vacuum degassing. After pressing, the film-applying device vacuums the first adhesive film to remove air bubbles between it and the lamp panel module.

5. The Mini LED packaging process for integrated multi-module splicing screens according to claim 1, characterized in that, The first adhesive layer is a liquid adhesive, which is applied to the entire module by spraying.

6. The Mini LED packaging process for integrated multi-module splicing screens according to claim 5, characterized in that, A vacuum degassing step is added after step (5) and before step (6).

7. The Mini LED packaging process for integrated multi-module splicing screens according to claim 1, characterized in that, The second adhesive film is a composite film of semi-solid adhesive and protective film, with the protective film at the top of the LED module.

8. The Mini LED packaging process for integrated multi-module splicing screens according to claim 1, characterized in that, The first adhesive film is a UV adhesive, EVA adhesive, or OCA adhesive, and the second adhesive film is a composite film of EVA adhesive or OCA adhesive and PET film.

9. The Mini LED packaging process for integrated multi-module splicing screens according to claim 2, characterized in that, The box or fixture is equipped with positioning pins, which are used to position the screen in conjunction with the process edge during the splicing process.

10. The Mini LED packaging process for integrated multi-module splicing screens according to claim 2, characterized in that, The width of the process edge is 1 to 10 mm.

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