PCB pressing structure and cavity PCB

Abstract

The utility model relates to the technical field of PCBs, and discloses a PCB press-fit structure and a cavity PCB, the press-fit structure comprises a bottom layer core board and a top layer core board, the bottom layer core board and the top layer core board are respectively arranged on the bottom side and the top side of the press-fit structure; the cavity wall assembly is arranged between the bottom-layer core plate and the top-layer core plate and surrounds a target cavity area, the cavity wall assembly comprises a surrounding frame part, and the bottom-layer core plate and the top-layer core plate are subjected to alignment press fit to form the press fit structure; in the pressing structure, the parts, corresponding to the target cavity area, of the bottom-layer core plate and the top-layer core plate and the inner side wall of the surrounding frame part jointly form a cavity part in a surrounding mode. The cavity wall assembly is arranged between the bottom core board and the top core board, and the cavity wall assembly forms a part of the cavity wall, so that the structural strength of the cavity PCB is enhanced, and the stability of the structure of the cavity part is ensured in a bending state.

Description

Technical Field

[0001] The utility model relates to the technical field of PCB, in particular to a PCB pressing structure and a cavity PCB. Background Art

[0002] In high-speed PCB applications, even if the material has a lower dielectric constant and dielectric loss factor, it still cannot meet the requirements of low-loss transmission of high-speed signals. Since the dielectric constant of air is much lower than that of conventional resin materials, in order to meet the requirements of low-loss transmission of high-speed signals, cavity PCB (Printed Circuit Board) has emerged. Cavity PCB is a circuit board with an internal cavity structure. It has excellent electrical properties and mechanical strength, and is therefore widely used.

[0003] In some application scenarios, PCB needs to have bending properties to adapt to specific appearance or functional requirements, such as when used in wearable devices. However, since the overall structural strength of the cavity PCB is not as good as that of an ordinary PCB, it is easy to break or be damaged when bent, resulting in poor bending performance of the cavity PCB, which is difficult to meet usage requirements. Utility Model Content

[0004] The utility model provides a PCB pressing structure and a cavity PCB, so as to solve the problem that the bending performance of the cavity PCB in the prior art is poor and it is difficult to meet the use requirements.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A PCB pressing structure, comprising:

[0007] A bottom core plate and a top core plate, wherein the bottom core plate and the top core plate are respectively arranged on the bottom side and the top side of the pressed structure;

[0008] A cavity wall assembly is disposed between the bottom core plate and the top core plate and is disposed around a target cavity area. The cavity wall assembly includes a surrounding frame portion. The bottom core plate and the top core plate are aligned and pressed together to form the pressed structure.

[0009] In the pressed structure, the portions of the bottom core plate and the top core plate corresponding to the target cavity area are jointly surrounded with the inner side wall of the surrounding frame to form a cavity portion.

[0010] Optionally, in the PCB pressing structure, the cavity wall assembly further comprises at least one layer of intermediate core board, the intermediate core board is arranged between the surrounding frame portion and the top core board, a first window structure is arranged on the intermediate core board, and the bottom core board, the intermediate core board and the top core board are pressed together to form the pressing structure;

[0011] In the pressed structure, the portions of the bottom core plate and the top core plate corresponding to the target cavity area, and the surrounding frame portion and the inner side wall of the middle core plate are jointly arranged to form the cavity portion.

[0012] Optionally, in the PCB pressing structure, the position of the first window structure coincides with the central axis of the target cavity area, and the width of the first window structure is greater than or equal to the width of the target cavity area.

[0013] Optionally, in the PCB pressing structure, the total thickness of the cavity wall assembly is greater than or equal to the height of the target cavity area.

[0014] Optionally, in the PCB pressing structure, a first colloid is provided between the surrounding frame and the bottom core board, a second colloid is provided between the surrounding frame and the middle core board, and a third colloid is provided between the middle core board and the top core board;

[0015] The thickness of the first colloid is greater than the thickness of the circuit on the bottom core board.

[0016] Optionally, in the PCB pressing structure, the outer sides of the bottom core board and the top core board are both provided with a covering layer, and the covering layer is provided with a second window structure;

[0017] In the pressed structure, the second window structure coincides with the central axis of the cavity portion, and the width of the second window structure is smaller than the width of the cavity portion.

[0018] Optionally, in the PCB pressing structure, the frame portion is arranged on the signal layer of the bottom core board; the inner width of the frame portion is greater than or equal to the width of the target cavity area; and the height of the frame portion is greater than the height of the target cavity area.

[0019] Optionally, in the PCB pressing structure, the surrounding frame portion is formed by a plurality of surrounding edge bodies connected end to end, and the surrounding edge bodies are in a long strip shape.

[0020] Optionally, in the PCB pressing structure, the surrounding frame portion is formed by a plurality of surrounding edge bodies connected end to end, the surrounding edge bodies include a plurality of protrusions, and the plurality of protrusions are arranged at intervals to form a dotted line shape.

[0021] On the other hand, the utility model provides a cavity PCB, comprising the PCB pressing structure as described in any one of the above items.

[0022] Compared with the prior art, the utility model has the following beneficial effects:

[0023] The utility model provides a PCB pressing structure and a cavity PCB, which arrange a cavity wall component between a bottom core board and a top core board. The cavity wall component constitutes a part of the cavity wall, thereby enhancing the structural strength of the cavity PCB and facilitating ensuring the stability of the cavity structure in a bent state.

[0024] The present invention has other characteristics and advantages, which will be apparent from the accompanying drawings and subsequent specific embodiments incorporated herein, or will be described in detail in the accompanying drawings and subsequent specific embodiments incorporated herein, which together are used to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 A schematic structural diagram of a PCB pressing structure provided by an embodiment of the utility model;

[0027] Figure 2 Another structural schematic diagram of a PCB pressing structure provided by an embodiment of the utility model;

[0028] Figure 3 A schematic structural diagram of a cavity PCB provided in an embodiment of the utility model.

[0029] Figure numerals: 10, bottom core board; 11, circuit layer; 12, silver immersion layer; 20, frame portion; 30, top core board; 40, middle core board; 41, first window structure; 51, first colloid; 52, second colloid; 53, third colloid; 60, coating layer; 61, second window structure; 70, cavity portion; 80, alignment structure. DETAILED DESCRIPTION

[0030] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0031] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0032] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0033] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0034] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0035] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0036] Similar to the understanding in the Examination Guidelines, in this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0037] In the description of the embodiments of the present application, space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the referred device or component must have a specific position, a specific orientation, or be constructed or operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0038] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms such as "install", "connect", "connect", "fix", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For technicians in the technical field to which the present application belongs, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0039] Embodiment 1

[0040] In view of the defect of poor bending performance of the hollow cavity PCB in the above-mentioned prior art, the applicant has actively carried out research and innovation based on many years of rich practical experience and professional knowledge in the design and manufacture of such products, and in conjunction with the application of academic theories. After continuous research and design, and repeated trial samples and improvements, the applicant finally created the present utility model which is truly of practical value.

[0041] Please refer to Figure 1 The present utility model embodiment provides a PCB pressing structure, including:

[0042] A bottom core plate 10 and a top core plate 30, wherein the bottom core plate 10 and the top core plate 30 are respectively arranged at the bottom side and the top side of the press-fit structure;

[0043] The cavity wall assembly is disposed between the bottom core board 10 and the top core board 30 and is disposed around a target cavity area. The cavity wall assembly includes a surrounding frame portion 20. The bottom core board 10 and the top core board 30 are aligned and pressed together to form a pressed structure.

[0044] Among them, the bottom core board 10 and the top core board 30 are both provided with alignment structures 80, such as alignment holes, alignment bumps, etc. The bottom core board 10 and the top core board 30 are aligned and overlapped through the alignment structure 80, and then pressed together under high temperature and high pressure conditions to form a pressed structure.

[0045] Specifically, in the pressed structure, the bottom core plate 10 and the top core plate 30 corresponding to the target cavity area are jointly surrounded by the inner side wall of the surrounding frame portion 20 to form a cavity portion 60 .

[0046] In this embodiment, the bottom core board 10, the middle core board 40 and the top core board 30 are aligned and pressed together to form a pressed structure, and the cavity portion 60 is formed by the cavity wall structure, thereby improving the overall strength and stability of the PCB and solving the problem of poor bending performance of the cavity PCB.

[0047] It can be understood that, among them, the bottom core board 10, the middle core board 40 and the top core board 30 are all provided with an alignment structure 80, such as an alignment hole, an alignment bump, etc., and the bottom core board 10, the middle core board 40 and the top core board 30 are aligned and overlapped through the alignment structure 80, and then pressed under high temperature and high pressure conditions to form the aforementioned pressed structure.

[0048] Please refer to Figure 2 Furthermore, in the PCB pressing structure of the present embodiment, the cavity wall assembly also includes at least one layer of intermediate core board 40, the intermediate core board 40 is arranged between the frame portion 20 and the top core board 30, and a first window structure 41 is provided on the intermediate core board 40. The bottom core board 10, the intermediate core board 40 and the top core board 30 are pressed together to form a pressing structure; in the pressing structure, the bottom core board 10 and the top core board 30 corresponding to the target cavity area, as well as the inner side walls of the frame portion 20 and the intermediate core board 40 are jointly arranged to form a cavity portion 60.

[0049] It is understandable that, by providing the middle core plate 40 to further combine with the surrounding frame portion 20 to form the cavity portion 60 , it is beneficial to realize arbitrary adjustment of the height of the cavity portion 60 , so as to adapt to different application scenarios.

[0050] Furthermore, in the PCB pressing structure of this embodiment, the position of the first window structure 41 coincides with the central axis of the target cavity area, and the width d1 of the first window structure 41 is greater than or equal to the width of the target cavity area. The width of the first window is made greater than the width of the target cavity area in order to ensure that the size of the formed cavity portion 60 meets actual needs.

[0051] Further, in the PCB pressing structure of this embodiment, the total thickness h1 of the cavity wall assembly is greater than or equal to the height of the target cavity area. Specifically, the total thickness h1 of the cavity wall assembly 40 is 1 to 1.6 times the height of the target cavity.

[0052] Furthermore, in order to increase the connection reliability between the frame portion 20 and the bottom core panel 10, the middle core panel 40, and the middle core panel 40 and the top core panel 30, in this embodiment, a first colloid 51 is provided between the frame portion 20 and the bottom core panel 10, a second colloid 52 is provided between the frame portion 20 and the middle core panel 40, and a third colloid 53 is provided between the middle core panel 40 and the top core panel 30. The setting of the colloid can increase the strength and reliability of the connection.

[0053] Specifically, the width difference between the first colloid 51 and the second colloid 52 and the width of the surrounding frame 20 is 0.1-0.2, and the width difference between the third colloid 53 and the width of the middle core plate 40 is 0.1-0.2, so as to avoid overflow of glue after lamination.

[0054] In this embodiment, the thickness h2 of the first colloid 51 is greater than the thickness h3 of the circuit on the bottom core board 10 , so that the first colloid 51 can be fully combined with the surrounding frame 20 , which is beneficial to improve the bonding stability of the surrounding frame 20 .

[0055] Furthermore, in the PCB pressing structure of the present embodiment, a coating layer 60 is provided on the outer sides of the bottom core board 10 and the top core board 30 , and the coating layer 60 is provided with a second window structure 61 .

[0056] Among them, in the pressed structure, the second window structure coincides with the central axis of the cavity portion 60, and the width d2 of the second window structure 61 is smaller than the width of the cavity portion 60, that is, the width d1 of the aforementioned first window structure 41. It can be understood that when the width of the second window is smaller than the width of the cavity portion 60, along the stacking direction of the bottom core plate 10 and the top core plate 30, the coating layer 60 and the first colloid 51, the second colloid 52 and the third colloid 53 all have overlapping parts, and the width of the overlapping part is about 0.2 to 0.3 mm, so that further pressing force can be provided for each layer of colloid during pressing, thereby ensuring the pressing stability between the bottom core plate 10, the surrounding frame portion 20, the middle core plate 40 and the top core plate 30.

[0057] Optionally, when the cavity wall assembly only includes a frame portion 20, the frame portion 20 is arranged on the signal layer of the underlying core board 10; wherein, the inner width of the frame portion 20 is greater than or equal to the width of the target cavity area; and the height of the frame portion 20 is greater than the height of the target cavity area to ensure that the size of the formed cavity portion 60 meets actual needs.

[0058] Furthermore, in the PCB pressing structure of the present embodiment, the frame portion 20 is formed by a plurality of edge bodies connected end to end, and the edge bodies are in the shape of long strips. At this time, the frame portion 20 forms a coherent surrounding frame, which is conducive to providing strong structural strength and avoiding breakage or deformation in scenarios where the cavity PCB needs to be bent.

[0059] Furthermore, in the PCB pressing structure of this embodiment, the frame portion 20 is formed by a plurality of surrounding edge bodies connected end to end, the surrounding edge bodies include a plurality of protrusions, and the plurality of protrusions are arranged at intervals to form a dotted line shape. The dotted line structure is beneficial to further improve the bendability of the cavity PCB.

[0060] The material of the surrounding frame portion 20 is polyimide, which has bendability and can disperse the stress generated during bending, play a protective and supporting role, and effectively improve the bendability of the cavity PCB.

[0061] It is understandable that in the PCB field, high-speed PCB products are generally treated with silver immersion. Since the soft board core board commonly used in the industry is relatively thin, with a thickness of about 1 to 4 mils, and the silver immersion treatment generally requires the core board thickness ≥ 6 mils, otherwise the silver immersion of a single core board is prone to wrinkles, and the bonding strength between the silver layer and the pure glue is poor, and it is easy to delaminate. In addition, the circuit in the cavity uses a local silver immersion process, that is, the signal line in the cavity area is silver-immersed, and the circuit in the non-cavity area is not silver-immersed. If a bonding tape is used to achieve the purpose of local silver immersion, the tape has problems of biased bonding and unsolid pressure of the tape, which leads to the risk of contamination; in the local protection process of copper etching dry film, for example, the bonded dry film needs to be stripped, and the stripping solution will attack the silver immersion layer 12. Therefore, the local silver immersion process for the circuit in the cavity area is currently difficult to produce.

[0062] On the basis of the PCB pressing structure provided in the present embodiment, an intermediate core board 40 is added to increase the overall thickness of the PCB, thereby meeting the requirement of local silver immersion for board thickness.

[0063] Specifically, after the middle core board 40 is pressed, the silver treatment is performed. During the silver treatment, the groove of the middle stack is set downward to avoid the accumulation of silver solution. After the circuit on the middle core board 40 is removed by etching, the exposed part is a polyimide material, which does not react with the silver solution, and the exposed part of the bottom core board 10 has a circuit layer 11 and an outer copper layer. These parts will react with the silver solution to form a silver layer 12, thereby achieving the effect of local silver treatment without affecting the bonding force between the various layers of the PCB structure.

[0064] Embodiment 2

[0065] An embodiment of the utility model provides a cavity PCB, comprising any one of the above PCB pressing structures.

[0066] On the basis of the PCB pressing structure provided in the above-mentioned embodiment, the gold or silver layer on the outer side of the bottom core board 10 and the top core board 30 is ground off by a grinding tool, and then drilling, electroplating, outer layer circuits and shapes are made according to the process to obtain the cavity PCB in this embodiment, such as Figure 3 shown.

[0067] In the cavity PCB provided in this embodiment, since a surrounding frame 20 is arranged around the cavity, it is not easy to cause the core board at the cavity position to collapse during the pressing process of each layer of core board; the surrounding frame 20 can disperse the stress and pressure during bending, play a protective and supporting role, and effectively improve the bendability of the cavity PCB. In addition, since the signal layer is treated with silver, it has good insertion loss performance, good interlayer bonding strength and high reliability, which solves the problem that the circuit at the cavity position cannot be treated with silver.

[0068] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A PCB pressing structure, characterized in that: include: A bottom core plate and a top core plate, wherein the bottom core plate and the top core plate are respectively arranged on the bottom side and the top side of the pressed structure; A cavity wall assembly is disposed between the bottom core plate and the top core plate and is disposed around a target cavity area. The cavity wall assembly includes a surrounding frame portion. The bottom core plate and the top core plate are aligned and pressed together to form the pressed structure. In the pressed structure, the portions of the bottom core plate and the top core plate corresponding to the target cavity area are jointly surrounded with the inner side wall of the surrounding frame to form a cavity portion.

2. The PCB pressing structure according to claim 1, characterized in that: The cavity wall assembly further comprises at least one layer of intermediate core plate, the intermediate core plate being arranged between the surrounding frame portion and the top core plate, the intermediate core plate being provided with a first window structure, and the bottom core plate, the intermediate core plate and the top core plate being aligned and pressed together to form the pressed structure; In the pressed structure, the portions of the bottom core plate and the top core plate corresponding to the target cavity area, and the surrounding frame portion and the inner side wall of the middle core plate are jointly arranged to form the cavity portion.

3. The PCB pressing structure according to claim 2, characterized in that: The position of the first window structure coincides with the central axis of the target cavity area, and the width of the first window structure is greater than or equal to the width of the target cavity area.

4. The PCB pressing structure according to claim 2 or 3, characterized in that: The total thickness of the cavity wall component is greater than or equal to the height of the target cavity area.

5. The PCB pressing structure according to claim 2, characterized in that: A first colloid is provided between the surrounding frame and the bottom core plate, a second colloid is provided between the surrounding frame and the middle core plate, and a third colloid is provided between the middle core plate and the top core plate; The thickness of the first colloid is greater than the thickness of the circuit on the bottom core board.

6. The PCB pressing structure according to claim 5, characterized in that: The outer sides of the bottom core plate and the top core plate are both provided with a covering layer, and the covering layer is provided with a second window structure; In the pressed structure, the second window structure coincides with the central axis of the cavity portion, and the width of the second window structure is smaller than the width of the cavity portion.

7. The PCB pressing structure according to claim 1, characterized in that: The frame portion is arranged on the signal layer of the bottom core board; the inner width of the frame portion is greater than or equal to the width of the target cavity area; and the height of the frame portion is greater than the height of the target cavity area.

8. The PCB pressing structure according to claim 1, characterized in that: The surrounding frame portion is formed by a plurality of surrounding edge bodies connected end to end, and the surrounding edge bodies are in a long strip shape.

9. The PCB pressing structure according to claim 1, characterized in that: The surrounding frame portion is formed by a plurality of surrounding edge bodies connected end to end, and the surrounding edge bodies include a plurality of protrusions, and the plurality of protrusions are arranged at intervals to form a dotted line shape.

10. A cavity PCB, characterized in that: It comprises a PCB pressing structure as described in any one of claims 1 to 9.

Images