Printed circuit board, display module and LED display device

Abstract

The utility model provides a printed circuit board, a display module and an LED display device. The printed circuit board comprises a substrate; the solder mask layer is arranged on the front surface of the substrate and is provided with a welding window; the circuit bonding pad is arranged on the front surface of the substrate, the circuit bonding pad is located below the solder mask, and the circuit bonding pad is provided with a plurality of connecting parts extending into the welding window; the bonding pad group is arranged on the front surface of the substrate and located in the welding window, the bonding pad group comprises a plurality of LED chip bonding pads, and the plurality of LED chip bonding pads are connected with the plurality of connecting parts in a one-to-one correspondence manner; the distance D2 between every two adjacent connecting parts is larger than the distance between every two corresponding adjacent LED chip bonding pads D4, and the minimum distance D1 between the edge of the welding window and the LED chip bonding pads ranges from 5 micrometers to 75 micrometers. According to the technical scheme provided by the invention, the problem that the product quality is influenced due to the fact that foreign matters are easily accumulated on the recess of the solder mask layer on the inner wall of the welding window in the related technology can be solved.

Description

Technical Field

[0001] This utility model relates to the field of LED display technology, and more specifically, to a printed circuit board, a display module, and an LED display device. Background Technology

[0002] The display unit (or PCB) includes a printed circuit board (PCB) and multiple LED chips. The PCB includes a substrate, circuit pads, and multiple LED chip pads. The circuit pads are located on the front side of the substrate, and the LED chip pads are also located on the front side of the substrate and electrically connected to the circuit pads. Each LED chip is positioned one-to-one on its corresponding LED chip pad. As the spacing between display modules decreases, the package size of the display modules shrinks, the circuit pads become denser, and the spacing between adjacent LED chip pads also decreases, placing increasingly higher demands on the processing of the PCB.

[0003] In related technologies, printed circuit boards also include a solder resist layer, which is disposed on the front side of the substrate. The solder resist layer has a soldering window, which covers the substrate and circuit pads, and multiple LED chip pads are located within the soldering window.

[0004] However, in related technologies, the solder resist layer is prone to depressions on the inner wall of the soldering window near the substrate. Foreign matter can easily accumulate in these depressions, affecting product quality. Utility Model Content

[0005] This invention provides a printed circuit board, a display module, and an LED display device to solve the problem in related technologies where foreign matter easily accumulates in the recesses on the inner wall of the soldering window of the solder resist layer, affecting product quality.

[0006] According to one aspect of the present invention, a printed circuit board is provided, comprising: a substrate; a solder resist layer disposed on the front side of the substrate, the solder resist layer having a soldering window; circuit pads disposed on the front side of the substrate, the circuit pads being located below the solder resist layer, the circuit pads having a plurality of connecting portions extending into the soldering window; and a pad group disposed on the front side of the substrate and located within the soldering window, the pad group including a plurality of LED chip pads, the plurality of LED chip pads being connected to the plurality of connecting portions in a one-to-one correspondence; wherein, the distance D2 between two adjacent connecting portions is greater than the distance D4 between two corresponding adjacent LED chip pads, and the minimum distance D1 between the edge of the soldering window and the LED chip pads is between 5 μm and 75 μm.

[0007] Furthermore, the minimum spacing D1 between the edge of the soldering window and the LED chip pad is between 30μm and 50μm.

[0008] Furthermore, the projection of the welding window onto the substrate is a polygonal structure, and the spacing D2 between two adjacent connecting parts located on the same side of the polygonal structure is greater than 80μm.

[0009] Furthermore, the distance D2 between two adjacent connecting parts located on the same side of the polygonal structure is less than or equal to 150 μm.

[0010] Furthermore, the width D3 of the connector is between 5μm and 50μm.

[0011] Furthermore, the pad group includes a first pad row and a second pad row, which are arranged along a first direction. Both the first pad row and the second pad row include multiple LED chip pads arranged along a second direction, which are perpendicular to the second direction.

[0012] Furthermore, among the plurality of connections, the connection that connects to the first pad row is located on the side of the first pad row away from the second pad row, and the connection that connects to the second pad row is located on the side of the second pad row away from the first pad row.

[0013] Furthermore, the spacing D4 between two adjacent LED chip pads is between 30μm and 60μm; and / or, the pad width D5 of the LED chip pad is between 70μm and 110μm, and the pad length D6 of the LED chip pad is between 100μm and 200μm.

[0014] According to another aspect of the present invention, a display module is provided, the display module comprising: a plurality of LED chips; a printed circuit board, wherein the plurality of LED chips are disposed one-to-one on a plurality of pads on the printed circuit board, and the printed circuit board is the printed circuit board provided above.

[0015] According to another aspect of the present invention, an LED display device is provided, which includes the display module provided above.

[0016] The technical solution of this utility model includes a printed circuit board comprising a substrate, a solder mask layer, circuit pads, and pad groups. Even if the solder mask layer has a depression on the inner wall of the soldering window near the substrate, the minimum distance D1 between the edge of the soldering window and the LED chip pads is between 5μm and 75μm, resulting in a gap between the edge of the soldering window and the LED chip pads. Furthermore, multiple connecting parts extending into the soldering window are provided to connect the multiple LED chip pads to the multiple connecting parts one by one. Since the distance D2 between two adjacent connecting parts is greater than the distance D4 between two adjacent LED chip pads, the impact of foreign matter accumulated in the depression on the circuit distance and safety distance between two adjacent LED chip pads is reduced. This helps to improve the product quality and reliability of the printed circuit board and reduce the maintenance cost of the LED display device. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0018] Figure 1 A schematic diagram of the structure of a printed circuit board provided in a prior art embodiment is shown;

[0019] Figure 2 It shows Figure 1 Sectional view at point AA;

[0020] Figure 3 A schematic diagram of the structure of the printed circuit board provided in an embodiment of the present invention is shown.

[0021] The above figures include the following reference numerals:

[0022] 1. Substrate; 2. Solder resist layer; 3. LED chip pads; 4. Soldering window; 5. Recess;

[0023] 10. Substrate;

[0024] 20. Solder resist layer; 21. Welding window;

[0025] 30. Circuit pads; 31. Connector;

[0026] 40. Pad group; 41. LED chip pad; 42. First pad row; 43. Second pad row;

[0027] D1, the minimum distance between the edge of the welding window and the LED chip pad;

[0028] D2. The distance between two adjacent connecting parts;

[0029] D3, Width of the connecting part;

[0030] D4. Spacing between two adjacent LED chip pads;

[0031] D5, the width of the LED chip pad;

[0032] D6, the length of the LED chip pad. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0034] like Figure 1 and Figure 2 As shown, the existing printed circuit board includes a substrate 1, circuit pads, and multiple LED chip pads 3. The circuit pads are disposed on the front side of the substrate 1, and the multiple LED chip pads 3 are disposed on the front side of the substrate 1 and electrically connected to the circuit pads. Multiple LED chips are disposed one-to-one on the multiple LED chip pads 3. The printed circuit board also includes a solder resist layer 2, which is disposed on the front side of the substrate 1. The solder resist layer 2 has a soldering window 4, which covers the substrate 1 and the circuit pads. The multiple LED chip pads 3 are located within the soldering window 4. The inner wall of the solder resist layer 2 near the substrate 1 is prone to developing a depression 5. Foreign matter (such as metal particles from machine wear during the production process, palladium residue in the nickel-gold plating solution, etc.) can easily accumulate in the depression 5, and the inner wall of the soldering window 4 between two adjacent LED chip pads 3 is more prone to developing depression 5. In the subsequent nickel-gold plating process, the accumulation of foreign matter in the depression 5 will cause the safety distance between two adjacent LED chip pads 3 to become smaller and smaller. In subsequent LED chip soldering, foreign matter buildup in the depression 5 can easily cause short circuits between adjacent LED chip pads 3 due to solder paste, or insufficient circuit distance between adjacent LED chip pads 3. These problems lead to a decline in the quality of the printed circuit board after packaging. Under high humidity conditions, the printed circuit board is prone to failure, and the risk of electromigration failure is greatly increased, resulting in a gradual increase in the defect rate of printed circuit boards in both substrate processing and packaging processes in existing technologies.

[0035] Furthermore, as the pitch of LED direct-view products becomes smaller, the product packaging volume becomes smaller, and the circuits become denser and finer, the requirements for substrate processing and packaging processing become increasingly stringent. The number of pixels in existing LED display devices ranges from several million to hundreds of millions, and even a defective pixel count at the ppm level can lead to huge repair costs.

[0036] like Figure 3 As shown, this embodiment of the present invention provides a printed circuit board, which includes a substrate 10, a solder resist layer 20, circuit pads 30, and a pad group 40. The solder resist layer 20 is disposed on the front side of the substrate 10 and has a soldering window 21. The circuit pads 30 are disposed on the front side of the substrate 10 and are located below the solder resist layer 20. The circuit pads 30 have multiple connecting portions 31 extending into the soldering window 21. The pad group 40 is disposed on the front side of the substrate 10 and located within the soldering window 21. The pad group 40 includes multiple LED chip pads 41, and the multiple LED chip pads 41 are connected to the multiple connecting portions 31 one-to-one. The distance D2 between two adjacent connecting portions 31 is greater than the distance D4 between two corresponding adjacent LED chip pads 41. The minimum distance D1 between the edge of the soldering window 21 and the LED chip pads 41 is between 5μm and 75μm.

[0037] The printed circuit board provided in this embodiment includes a substrate 10, a solder mask layer 20, circuit pads 30, and a pad group 40. Even if the solder mask layer 20 has a depression on the inner wall of the soldering window 21 near the substrate 10, since the minimum distance D1 between the edge of the soldering window 21 and the LED chip pad 41 is between 5μm and 75μm, there is a gap between the edge of the soldering window 21 and the LED chip pad 41. Furthermore, multiple connecting portions 31 extending into the soldering window 21 are provided to connect the multiple LED chip pads 41 to the multiple connecting portions 31 one by one. Since the distance D2 between two adjacent connecting portions 31 is greater than the distance D4 between two adjacent LED chip pads 41, the impact of foreign matter accumulated in the depression on the circuit distance and safety distance between two adjacent LED chip pads 41 is reduced. This helps to improve the product quality and reliability of the printed circuit board and reduce the maintenance cost of the LED display device.

[0038] like Figure 3 As shown, the minimum spacing D1 between the edge of the soldering window 21 and the LED chip pad 41 is between 30μm and 50μm. This spacing design further reduces the impact of foreign matter buildup in the recess on the circuit distance and safety distance between adjacent LED chip pads 41, ensuring the stability of the LED chip pads 41 and the reliability of the circuit.

[0039] The minimum spacing D1 between the edge of the welding window 21 and the LED chip pad 41 can be any value between 30μm, 35μm, 40μm, 45μm, 50μm, and 30μm to 50μm.

[0040] like Figure 3 As shown, the projection of the soldering window 21 onto the substrate 10 is a polygonal structure, and the distance D2 between two adjacent connecting portions 31 located on the same side of the polygonal structure is greater than 80 μm. This layout further reduces the impact of foreign matter accumulation within the recess on the circuit distance and safety distance between adjacent LED chip pads 41, and ensures the wiring density and signal transmission stability of the printed circuit board. It is suitable for LED display devices requiring high-density wiring and high-quality signal transmission. By optimizing the layout between the connecting portions, signal interference is reduced, and the speed and accuracy of data transmission are improved.

[0041] like Figure 3 As shown, the spacing D2 between two adjacent connecting portions 31 located on the same side of the polygonal structure is less than or equal to 150 μm. Using this spacing range helps maintain the wiring density of the printed circuit board.

[0042] like Figure 3 As shown, the width D3 of the connector 31 is between 5μm and 50μm. This width design improves the reliability of the connection between the connector 31 and the LED chip pads, reduces thermal stress during soldering, and enhances soldering quality and circuit board lifespan.

[0043] The width D3 of the connecting part 31 can be any value between 25μm, 30μm, 35μm, 40μm, 29μm and 30μm to 60μm.

[0044] like Figure 3 As shown, the pad group 40 includes a first pad row 42 and a second pad row 43, which are arranged along a first direction. Both the first pad row 42 and the second pad row 43 include multiple LED chip pads 41 arranged along a second direction, which are perpendicular to the second direction. This arrangement effectively utilizes space, improves the integration of the circuit board, and the vertical arrangement makes the assembly of the LED chip pads 41 and the LED chips more standardized, facilitating automated assembly and improving production efficiency and assembly quality.

[0045] like Figure 3As shown, among the plurality of connection portions 31, the connection portion 31 connected to the first pad row 42 is located on the side of the first pad row 42 opposite to the second pad row 43, and the connection portion 31 connected to the second pad row 43 is located on the side of the second pad row 43 opposite to the first pad row 42. This arrangement avoids mutual interference between the connection portions 31 connected to the first pad row 42 and the connection portions 31 connected to the second pad row 43, thus improving the stability and reliability of the circuit.

[0046] like Figure 3 As shown, the spacing D4 between two adjacent LED chip pads 41 is between 30μm and 60μm. This dimensional design improves the circuit distance and safety distance between adjacent LED chip pads 41, ensuring high wiring density and stable signal transmission on the printed circuit board. It is suitable for LED display devices requiring high-density wiring and high-quality signal transmission.

[0047] The spacing D4 between two adjacent LED chip pads 41 can be any value between 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, and 30μm to 60μm.

[0048] In the LED display devices with P0.4 to P1.25, the spacing between two adjacent LED chips is between 30μm and 60μm.

[0049] like Figure 3 As shown, the pad width D5 of the LED chip pad 41 is between 60μm and 100μm, and the pad length D6 of the LED chip pad 41 is between 150μm and 200μm. Specifically, the pad width D5 of the LED chip pad 41 can be any value between 60μm, 70μm, 80μm, 90μm, 100μm, and 60μm to 100μm, and the pad length D6 of the LED chip pad 41 can be any value between 150μm, 160μm, 170μm, 180μm, 190μm, 200μm, and 150μm to 200μm.

[0050] This embodiment of the present invention provides a display module, which includes a printed circuit board and multiple LED chips. The multiple LED chips are disposed one-to-one on multiple pads of the printed circuit board, which is the printed circuit board provided above. Using the display module provided in this embodiment, even if the solder mask layer 20 is recessed on the inner wall of the soldering window 21 near the substrate 10, because the minimum distance D1 between the edge of the soldering window 21 and the LED chip pads 41 is between 5μm and 75μm, there is a gap between the edge of the soldering window 21 and the LED chip pads 41. Multiple connecting portions 31 extending into the soldering window 21 are provided to connect the multiple LED chip pads 41 to the multiple connecting portions 31 one-to-one. Since the distance D2 between two adjacent connecting portions 31 is greater than the distance D4 between two adjacent LED chip pads 41, the impact of foreign matter accumulated in the recess on the circuit distance and safety distance between two adjacent LED chip pads 41 is reduced. This helps to improve the product quality and reliability of the printed circuit board and reduce the maintenance cost of the LED display device.

[0051] This utility model embodiment provides an LED display device, which includes the display module provided above. Using the LED display device provided in this embodiment, even if the solder resist layer 20 forms a depression on the inner wall of the soldering window 21 near the substrate 10, because the minimum distance D1 between the edge of the soldering window 21 and the LED chip pad 41 is between 5μm and 75μm, there is a gap between the edge of the soldering window 21 and the LED chip pad 41. Furthermore, multiple connecting portions 31 extending into the soldering window 21 are provided to connect the multiple LED chip pads 41 to the multiple connecting portions 31 one-to-one. Since the distance D2 between two adjacent connecting portions 31 is greater than the distance D4 between two corresponding adjacent LED chip pads 41, the impact of foreign matter accumulated in the depression on the circuit distance and safety distance between two adjacent LED chip pads 41 is reduced. This helps improve the product quality and reliability of the printed circuit board and reduces the maintenance cost of the LED display device.

[0052] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0053] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0054] In the description of this utility model, it should be understood that the directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this utility model. The directional terms "inner" and "outer" refer to the inner and outer contours of each component itself.

[0055] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0056] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this utility model.

[0057] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A printed circuit board, characterized in that, The printed circuit board includes: base(10); A solder resist layer (20) is disposed on the front side of the substrate (10), and the solder resist layer (20) has a solder window (21); Line pads (30) are disposed on the front side of the substrate (10), the line pads (30) are located below the solder mask layer (20), and the line pads (30) have a plurality of connections (31) extending into the solder window (21). A pad group (40) is disposed on the front side of the substrate (10) and located within the welding window (21). The pad group (40) includes a plurality of LED chip pads (41), and the plurality of LED chip pads (41) are connected to the plurality of connecting parts (31) in a one-to-one correspondence. The distance D2 between two adjacent connecting parts (31) is greater than the distance D4 between two adjacent LED chip pads (41), and the minimum distance D1 between the edge of the welding window (21) and the LED chip pad (41) is between 5μm and 75μm.

2. The printed circuit board according to claim 1, characterized in that, The minimum spacing D1 between the edge of the welding window (21) and the LED chip pad (41) is between 30 μm and 50 μm.

3. The printed circuit board according to claim 1, characterized in that, The projection of the welding window (21) onto the substrate (10) is a polygonal structure, and the distance D2 between two adjacent connecting parts (31) located on the same side of the polygonal structure is greater than 80 μm.

4. The printed circuit board according to claim 3, characterized in that, The distance D2 between two adjacent connecting parts (31) located on the same side of the polygonal structure is less than or equal to 150 μm.

5. The printed circuit board according to claim 1, characterized in that, The width D3 of the connecting part (31) is between 25 μm and 50 μm.

6. The printed circuit board according to claim 1, characterized in that, The pad group (40) includes a first pad row (42) and a second pad row (43). The first pad row (42) and the second pad row (43) are arranged along a first direction. The first pad row (42) and the second pad row (43) each include a plurality of LED chip pads (41) arranged along a second direction. The first direction is perpendicular to the second direction.

7. The printed circuit board according to claim 6, characterized in that, Of the plurality of connection portions (31), the connection portion (31) connected to the first pad row (42) is located on the side of the first pad row (42) away from the second pad row (43), and the connection portion (31) connected to the second pad row (43) is located on the side of the second pad row (43) away from the first pad row (42).

8. The printed circuit board according to claim 1, characterized in that, The spacing D4 between two adjacent LED chip pads (41) is between 30 μm and 60 μm; and / or, The width D5 of the LED chip pad (41) is between 70μm and 110μm, and the length D6 of the LED chip pad (41) is between 100μm and 200μm.

9. A display module, characterized in that, The display module includes: Multiple LED chips; A printed circuit board, wherein a plurality of LED chips are disposed one-to-one on a plurality of pads on the printed circuit board, the printed circuit board being the printed circuit board of claim 8.

10. An LED display device, characterized in that, The LED display device includes the display module as described in claim 9.

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