Dispensing structure of LED display module and display device

Abstract

The utility model relates to the technical field of LED display, in particular to a dispensing structure of an LED display module and a display device.The LED display module comprises a substrate, light-emitting units distributed on the substrate in an array mode and the dispensing structure, the dispensing structure comprises a black composite layer and a filling layer, and the composite layer comprises at least two box dams including the first box dam and the second box dam. The first box dams and the second box dams are arranged in parallel along a column-direction gap and / or a row-direction gap between the light-emitting units, the opposite side faces of every two adjacent box dams are connected, the filling layer covers the surface area, not covered by the composite layer, of the substrate on the peripheries of the light-emitting units and the local area of the composite layer, and the composite layer with the large width is formed by at least two box dams. The problem that the display contrast ratio is affected due to the fact that a single box dam and a filling layer incompletely shield the substrate is effectively avoided.

Description

Technical Field

[0001] The present application relates to the field of LED display technology, and in particular to a dispensing structure of an LED display module and a display device. Background Art

[0002] The preparation process of LED display module includes printing solder paste, solid crystal, dispensing glue, etc., wherein dispensing glue refers to applying and dripping glue containing melanin onto a substrate (such as a PCB board), and the glue is cured to form a glue film layer, which covers the surface of the substrate to improve the display contrast, etc. For example, the prior art provides an LED display screen module and a display device, with application number 2023223113314, which ensures that the substrate surface area around the light-emitting unit is completely blocked by arranging a black first glue film layer and a second glue film layer in the column gap and / or row gap between the light-emitting units. The first glue film layer is formed by curing the first liquid glue and is a single dam structure. The second glue film layer is formed by curing the second liquid glue. However, this glue film layer structure is only applicable to small-gap LED display modules, for example, the small gap width is 0.6 mm. For LED display modules with a larger gap width (for example, a gap width greater than or equal to 0.9 mm), if the above-mentioned single dam structure is adopted, there is still a problem that the second liquid glue cannot completely block the substrate surface and affect the display contrast.

[0003] At present, there are several ways to solve the above problems: (1) drip more second liquid glue while keeping the width of the longitudinal section of the single dam unchanged, but the increase in the amount of the second liquid glue is prone to glue creeping; (2) increase the width of the single dam while keeping the viscosity of the first liquid glue unchanged, but its height also increases, which is prone to cause the side of the light-emitting unit to be blocked and the light output to be reduced; (3) reduce the viscosity of the first liquid glue and increase the width of the single dam by overflowing the first liquid glue 401, but there is an uneven glue path of the first liquid glue (reference Figure 1 ), which leads to problems such as difficulty in controlling the amount of the subsequent second liquid glue.

[0004] In view of the above reasons, it is urgent to develop a dispensing structure that can be applicable to LED display modules with wider gaps. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present application provides a dispensing structure, which can ensure that the surface of the substrate in the LED display module with a wider gap width is completely covered.

[0006] To achieve the above objectives, this application adopts the following technical solutions:

[0007] A glue dispensing structure for an LED display module, the LED display module comprising a substrate, light-emitting units arrayed on the substrate, and a glue dispensing structure, a column-direction gap is provided between two adjacent columns of light-emitting units, a row-direction gap is provided between two adjacent rows of light-emitting units, the gap width of the column-direction gap and / or the gap width of the row-direction gap is greater than or equal to 0.9 mm, characterized in that the glue dispensing structure comprises a black composite layer and a filling layer;

[0008] The composite layer comprises at least two dams: a first dam and a second dam, wherein the first dam and the second dam are arranged in parallel along the column-direction gap and / or the row-direction gap, and are used to cover the surface of the substrate in the column-direction gap and / or the row-direction gap once, and opposite sides of two adjacent dams are connected;

[0009] The filling layer covers the substrate area around the light-emitting unit that is not covered by the composite layer, and a local area of ​​the composite layer.

[0010] Its further characteristic is that

[0011] The composite layer and the filling layer are both glue layers, and the viscosity of the first liquid glue of the composite layer before curing is greater than the viscosity of the second liquid glue of the filling layer before curing, that is, the viscosity of the second liquid glue used to form the filling layer is less than the viscosity of the first liquid glue used to form the composite layer.

[0012] Furthermore, the viscosity of the first liquid glue is 40000cps-60000cps, and the viscosity of the second liquid glue is 1000cps-4000cps.

[0013] Furthermore, the maximum thickness of the composite layer and the filling layer are both less than or equal to the gap height of the column-wise gap and / or the row-wise gap, and are both less than or equal to the thickness of the light-emitting unit.

[0014] Furthermore, the thickness of the light emitting unit is not less than 5 micrometers.

[0015] Furthermore, the maximum thickness of the filling layer is less than or equal to the maximum thickness of the composite layer.

[0016] Furthermore, the maximum width of the longitudinal section of the composite layer is set to a, the gap width of the column gap is set to b1, and the gap width of the row gap is set to b2, then 1 / 2*b1≤a≤b1, and / or, 1 / 2*b2≤a≤b2.

[0017] Furthermore, the upper surface of the composite layer is in a wave shape with a concave middle portion and convex sides.

[0018] Furthermore, the light-emitting unit is an LED chip or a package of an LED chip.

[0019] Furthermore, the gap width of the column-wise gap and the gap width of the row-wise gap are 0.9 mm to 2 mm.

[0020] Furthermore, the LED display module also includes a driving unit, and the driving unit is used to control the turning on or off of the light-emitting unit.

[0021] Furthermore, the driving unit is an IC chip, and the IC chip is arranged on the back side of the substrate and is electrically connected to the corresponding light-emitting unit.

[0022] Furthermore, a single light-emitting unit includes at least three LED chips of different primary colors: a red LED chip, a green LED chip, and a blue LED chip.

[0023] A display device comprises a plurality of LED display modules distributed in an array, wherein the LED display module comprises the above-mentioned dispensing structure of the LED display module.

[0024] The beneficial effect of the present application is: the dispensing structure of the present application is applied to an LED display module with a larger gap width, at least two dams are arranged in the column gap and / or row gap in the LED display module, the opposite sides of the two adjacent dams are connected to form a composite layer with a wider longitudinal cross-sectional width, and the composite layer is arranged on the surface of the substrate in the column gap and / or row gap to ensure that the substrate surface is completely blocked. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A top view of the existing method of increasing the width of a single dam by reducing the viscosity of the first liquid glue and causing the first liquid glue to overflow, with the first liquid glue path edge being uneven;

[0026] Figure 2 This is a schematic diagram of the top view of the dispensing structure of the LED display module of the present application;

[0027] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure of the local AA;

[0028] Figure 4 This is a top view of the dispensing structure of the LED display module of this application;

[0029] Figure 5 This is a top view of the LED display module of the present application in which a composite layer is provided but no filling layer is provided;

[0030] Figure 6 This is a schematic diagram of the top view structure of an LED display module without a composite layer or a filling layer;

[0031] Figure 7A schematic diagram of a top view structure in which a composite layer is arranged in both the column-direction gap and the row-direction gap of an LED display module;

[0032] Figure 8 The schematic diagram of the top view of the structure is that a single dam and a composite layer are respectively arranged in the column-wise gap and the row-wise gap of the LED display module.

[0033] Figure numerals: substrate 1, light-emitting unit 2, red LED chip 201, green LED chip 202, blue LED chip 203, column gap 3, row gap 4, first liquid glue 401, composite layer 5, first gap 500, first dam 501, second dam 502, filling layer 6. DETAILED DESCRIPTION

[0034] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0035] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, apparatus, product or equipment comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

[0036] In view of the technical problem that when the gap width of the LED display module is large, the single dam and the filling layer do not completely cover the substrate, thereby affecting the display contrast, the following provides a specific embodiment of the LED display module dispensing structure, with reference to Figure 2~Figure 5 The LED display module includes a substrate 1, light-emitting units 2 arrayed on the substrate 1, a dispensing structure, and a driving unit, wherein the light-emitting unit 2 includes three LED chips with different primary colors: a red LED chip 201, a green LED chip 202, and a blue LED chip 203. The driving unit is an IC chip (not shown in the figure). The IC chip is arranged on the back of the substrate 1 and is electrically connected to the corresponding LED chip for controlling the on or off of the LED chip.

[0037] A column-direction gap 3 is provided between two adjacent columns of light-emitting units 2, and a row-direction gap 4 is provided between two adjacent rows of light-emitting units 2. Figure 6The gap width of the column-wise gap 3 is 0.2-0.4 mm, and in this embodiment, preferably 0.3 mm. The gap width of the row-wise gap 4 is 0.9 mm-2 mm, and preferably 1 mm. The gap width of the row-wise gap 4 is relatively wide. In order to improve the coverage effect of the substrate 1, a black composite layer 5 is provided in the row-wise gap.

[0038] It should be noted that, in another embodiment, if the gap width of the column gap 3 and the gap width of the row gap 4 are both greater than or equal to 0.9 mm, the composite layer 5 may be disposed in both the column gap 3 and the row gap 4 .

[0039] The glue dispensing structure includes the above-mentioned composite layer 5, which includes at least two dams: a first dam 501 and a second dam 502. The first dam 501 and the second dam 502 are arranged in parallel along the row gap 4, and are used to cover the surface of the substrate in the row gap once. The first dam 501 and the second dam 502 are connected on opposite sides to form a wave shape with a depression in the middle and convexities on both sides.

[0040] The glue dispensing structure also includes a black filling layer 6 , which covers the surface area of ​​the substrate b around the light-emitting unit that is not covered by the composite layer 5 , as well as a local area of ​​the composite layer 5 .

[0041] The composite layer 5 and the filling layer 6 are both adhesive layers, which are formed by solidifying a first liquid adhesive and a second liquid adhesive respectively. The viscosity of the first liquid adhesive is greater than that of the second liquid adhesive, that is, the viscosity of the second liquid adhesive used to form the filling layer 6 is less than the viscosity of the first liquid adhesive used to form the composite layer 5. The viscosity of the first liquid adhesive is 40000cps-60000cps, and the viscosity of the second liquid adhesive is 1000-4000cps. In this embodiment, the preferred range of the viscosity of the first liquid adhesive is 53000cps-58000cps, and the surface tension is 24mN / m-25mN / m. The preferred range of the viscosity of the second liquid adhesive is 2000cps-3000cps, and the surface tension is 34mN / m-36mN / m.

[0042] In order to prevent the composite layer 5 and the filling layer 6 from blocking the light-emitting unit and affecting the light extraction efficiency, in the present application, the maximum thickness of the composite layer 5 and the maximum thickness of the filling layer 6 are both less than the gap height of the column gap 3, the gap height of the row gap 4, and the thickness of the light-emitting unit 2, wherein the thickness of the light-emitting unit 2 is not less than 5 microns. In the present embodiment, the thickness of the light-emitting unit 2 is 80 microns, and the height of the column gap 3 and the height of the row gap 4 are 90 microns respectively. The maximum thickness of the filling layer 6 is less than or equal to the maximum thickness of the composite layer 5.

[0043] Assuming the maximum width of the longitudinal section of the composite layer 5 to be a, the gap width of the column-wise gap 3 to be b1, and the gap width of the row-wise gap 4 to be b2, then 1 / 2*b2≤a<b2. In this embodiment, the maximum width of the longitudinal section of the composite layer 5 is preferably a=2 / 3*b2.

[0044] The dispensing structure of the LED display module is prepared by using a dispensing process, and the specific steps include:

[0045] S1. Provide a substrate 1 (i.e., a PCB board). The front side of the substrate 1 is welded with an array-distributed light-emitting unit 2. The back side of the substrate 1 is welded with an IC chip. The IC chip is electrically connected to the corresponding LED chip through the circuit in the PCB board to control the on or off of the LED chip.

[0046] S2. Use the first glue dispensing machine to perform glue dispensing in the row gap 4. The glue dispensing includes the first dam glue and the second dam glue. The first dam glue and the second dam glue in the same row gap are distributed in parallel in the row direction and are adjacent to each other.

[0047] In this case, the first dam glue and the second dam glue are both first liquid glue. The first liquid glue mainly includes epoxy resin, melanin, and curing agent. It is a high-viscosity glue produced by Guangzhou Polymer New Materials Technology Co., Ltd. The viscosity of the first liquid glue is 58,000 cps and the surface tension is 25 mN / m.

[0048] After one dispensing, the substrate 1 coated with the first liquid glue is placed in the first cache table cache and left to stand for 15 minutes to 25 minutes. The first liquid glue is in paste form, so it can drop to a certain height during the standing process. The first dam glue is connected to the opposite side of the second dam glue, and after standing, a wavy shape with a concave middle and convex sides is formed. The purpose of standing is to prevent the height of the first liquid glue from changing too much during subsequent curing, resulting in poor uniformity of the thickness of the final composite layer and affecting the uniformity of the subsequent secondary dispensing.

[0049] S3, using a first curing furnace to heat and cure the first liquid glue after standing to form a composite layer 5 composed of the first dam 501 and the second dam 502, the heating temperature is 130° C., and the first curing furnace is a first infrared curing furnace;

[0050] It should be noted that in another embodiment, laser heating curing or microwave heating curing can also be used. Infrared heating curing, laser heating curing or microwave heating curing are all beneficial to preventing the generation of bubbles in the glue liquid, further ensuring the flatness of the glue dispensing, which is beneficial to further improve the product yield.

[0051] A first gap 500 is formed between the composite layer 5 and the adjacent light emitting units.

[0052] S4. Use a second glue dispenser to perform secondary glue dispensing in the column gap 3. The second liquid glue flows toward the periphery and covers the local surface area of ​​the composite layer 5, as well as the substrate surface area not covered by the composite layer 5 in the column gap 3 and the row gap 4.

[0053] The second liquid glue includes epoxy resin, diffusion powder / diffusing agent, and melanin. The viscosity of the second liquid glue is 2500 cps, and the surface tension is 35 mN / m. The viscosity of the second liquid glue is less than that of the first liquid glue.

[0054] After the second dispensing, the substrate coated with the second liquid glue is placed in the second cache table and left to stand for 35 minutes to 50 minutes. The viscosity of the second liquid glue is lower than that of the first liquid glue. Therefore, it can quickly sink and flow to the surrounding during the standing process to fill the gap around the LED chip. In addition, since the viscosity of the second liquid glue is lower than that of the first liquid glue and it has high fluidity, it can quickly fill the unfilled first gap 500 between the composite layer 5 and the LED chip, thereby ensuring that the surface area of ​​the substrate b not covered by the composite layer 5 is completely blocked, thereby preventing the problem of poor display contrast due to incomplete blocking of the composite layer 5 obtained by one dispensing.

[0055] S5. A second curing oven is used to heat and cure the second liquid glue after standing to form a filling layer 6. The heating temperature is 130° C. The second curing oven is a second infrared curing oven. Both the first infrared curing oven and the second infrared curing oven are manufactured by Jiangsu Chuangyuan Electronics Co., Ltd., and the model is SM-350.

[0056] It should be noted that, in another embodiment, laser heating curing or microwave heating curing may also be used.

[0057] The dispensing structure of the above embodiment of the present application is mainly used in LED display modules in which the row gap width is much larger than the column gap width. In another embodiment, when the row gap width and the column gap width are both greater than or equal to 0.9 mm, a composite layer can be set in both the column gap and the row gap. Figure 7 , or according to the gap width (for example, the row gap width is 0.9 mm, and the column gap width is 0.6 mm), a composite layer 5 and a single dam 10 are respectively arranged in the row gap and the column gap, referring to Figure 8 , wherein the single dam 10 can be formed by dripping a row of first liquid glue in the row gap through a first glue dispenser, and the first liquid glue is solidified to achieve complete coverage of the substrate surface, thereby avoiding affecting the display contrast.

[0058] An LED display module includes the above-mentioned glue dispensing structure, and a protective film (not shown in the figure) is prepared on the front of the LED display module by a lamination process. The protective film covers the entire surface including the light-emitting unit 2, the composite layer 5, and the filling layer 6. The material of the protective film is preferably epoxy resin, which has the functions of light uniformity and light transmission. The LED display module including the above-mentioned glue dispensing structure is applied to a display device, which is composed of a plurality of LED display modules distributed in an array.

[0059] It is understandable that the above specific description of the present application is only used to illustrate the present application and is not limited to the technical solutions described in the embodiments of the present application. Those skilled in the art should understand that the present application can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the scope of protection of the present application.

Claims

1. A glue dispensing structure for an LED display module, the LED display module comprising a substrate (1), light emitting units (2) arranged in an array on the substrate (1), and a glue dispensing structure, wherein a column-direction gap (3) is provided between two adjacent columns of light emitting units (2), and a row-direction gap (4) is provided between two adjacent rows of light emitting units (2), wherein the gap width of the column-direction gap (3) and / or the gap width of the row-direction gap is greater than or equal to 0.9 mm, and wherein: The dispensing structure comprises a black composite layer (5) and a filling layer (6); The composite layer (5) comprises at least two dams: a first dam (501) and a second dam (502), wherein the first dam (501) and the second dam (502) are arranged in parallel along a column-wise gap (3) and / or a row-wise gap (4) with a gap width greater than or equal to 0.9 mm, and are used to cover the surface of the substrate within the column-wise gap (3) and / or the row-wise gap (4) at one time, and opposite sides of two adjacent dams are connected; The filling layer (6) covers the substrate area around the light-emitting unit that is not covered by the composite layer (5), as well as a local area of ​​the composite layer (5).

2. The glue dispensing structure of the LED display module according to claim 1, characterized in that: The composite layer (5) and the filling layer (6) are both adhesive layers, and the viscosity of the first liquid adhesive of the composite layer (5) before solidification is greater than the viscosity of the second liquid adhesive of the filling layer (6) before solidification.

3. The glue dispensing structure of the LED display module according to claim 2, characterized in that: The viscosity of the first liquid glue is 40000cps-60000cps, and the viscosity of the second liquid glue is 1000cps-4000cps.

4. The glue dispensing structure of the LED display module according to claim 3, characterized in that: The maximum thickness of the composite layer (5) and the filling layer (6) are both less than or equal to the gap height of the column-direction gap (3) and / or the row-direction gap (4), and are both less than or equal to the thickness of the light-emitting unit (2).

5. The glue dispensing structure of the LED display module according to claim 4, characterized in that: The maximum thickness of the filling layer (6) is less than or equal to the maximum thickness of the composite layer (5).

6. The glue dispensing structure of the LED display module according to claim 1, characterized in that: Assuming that the maximum width of the longitudinal section of the composite layer (5) is a, the gap width of the column-wise gap (3) is b1, and the gap width of the row-wise gap (4) is b2, then 1 / 2*b1≤a<b1, and / or, 1 / 2*b2≤a<b2.

7. The glue dispensing structure of the LED display module according to claim 1, characterized in that: The upper surface of the composite layer (5) is in a wave shape with a concave middle portion and convex sides.

8. A display device comprising a plurality of LED display modules distributed in an array, characterized in that: The LED display module comprises the dispensing structure of the LED display module according to any one of claims 1 to 7.

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