A rigid-flexible printed circuit board with a limiting structure

Abstract

This utility model relates to the field of printed circuit boards (PCBs) and discloses a rigid-flexible PCB with a limiting structure. The PCB includes at least two rigid PCBs, a flexible PCB connected between them, and a limiting structure. The limiting structure includes a limiting plate and a positioning piece, which are respectively fixed to the rigid PCBs. The limiting plate has a limiting groove that matches the positioning piece, and the two engage to achieve precise positioning of the flexible area. This structure eliminates the need for positioning holes on the rigid PCBs, preserving wiring space, improving design freedom and space utilization, while avoiding quality risks such as offset and open circuits caused by drilling, thus improving product yield and reliability. The overall structure is simple, easy to assemble, simplifies the production process, and reduces costs.

Description

Technical Field

[0001] This solution relates to the field of printed circuit boards, specifically to a rigid-flexible printed circuit board with a limiting structure. Background Technology

[0002] Printed Circuit Boards (PCBs) are essential electronic components, serving as the support for electronic components and the carrier for their electrical connections. Currently, with the rapid development of the PCB industry, their applications are becoming increasingly widespread. Any electronic component containing integrated circuits requires a PCB for their electrical interconnection. However, as the number of components increases, a larger area is needed to arrange them. Placing components on only one surface of the PCB requires a larger PCB size, occupies a significant amount of horizontal space, and results in large solder warpage, which is detrimental to production.

[0003] To address this issue, Chinese Patent Application No. 201910223300.9 discloses a circuit board comprising: a first rigid PCB, a second rigid PCB, and a flexible PCB. The first rigid PCB is electrically connected to the second rigid PCB via the flexible PCB. The first rigid PCB, the flexible PCB, and the second rigid PCB each include a first surface and a second surface. The first surface of the first rigid PCB, the first surface of the second rigid PCB, and the second surface of the second rigid PCB are used to mount electrical components. The first rigid PCB and the second rigid PCB can be folded between an unfolded state and a folded state to form an RFPC board. The second rigid PCB, in its folded state, is supported and limited by support posts fixed to the first surface of the first rigid PCB, buckles located at the free ends of the support posts, and slots located on the second rigid PCB, thereby reducing the horizontal space occupied by the PCB board.

[0004] However, setting a slot on the surface of the second PCB rigid board will inevitably narrow the routing range of the second PCB rigid board. When the module size requirements are strict and the size of the RFPC board is small, there is a risk of routing limits. Utility Model Content

[0005] The present invention aims to provide a rigid flexible printed circuit board with a limiting structure to improve the limiting structure of RFPC boards and avoid the limiting structure affecting the routing range of the PCB rigid board.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a rigid-flexible printed circuit board with a limiting structure, comprising a circuit board body and a limiting structure. The circuit board body comprises at least two rigid PCBs, and a flexible circuit board is disposed between the rigid PCBs and the two rigid PCBs are connected to each other through the flexible circuit board. The limiting structure comprises a limiting plate and a positioning piece. The limiting plate is provided with a limiting groove adapted to the outer edge of the positioning piece. The limiting plate and the positioning piece are respectively fixed on the surface of the two rigid PCBs and can form an engaging structure through the cooperation of the positioning piece and the limiting groove.

[0007] The beneficial effects of this solution are as follows: By setting up a limiting structure consisting of a limiting plate and a positioning piece, where the limiting plate has a limiting groove that matches the outer edge of the positioning piece, the two can cooperate to form a stable locking structure, thereby achieving effective limiting and precise positioning of the flexible area in a rigid-flexible printed circuit board (RFPC). This limiting structure eliminates the need for traditional positioning holes on the PCB rigid board, avoiding the space limitations on circuit layout caused by positioning hole placement, effectively preserving the complete wiring area of ​​the rigid board, expanding the freedom of routing design, and improving the flexibility and space utilization of circuit design.

[0008] Meanwhile, eliminating the positioning holes also reduces potential quality risks associated with drilling, such as hole misalignment, wire breakage, and short circuits, thus improving product yield and reliability. Furthermore, this limiting structure is simple in design and easy to assemble, not only enhancing the overall structural stability but also simplifying the production process and reducing processing costs, demonstrating its practicality and potential for widespread adoption.

[0009] Furthermore, the positioning piece is made of a polyurethane-based material that can undergo thermal deformation.

[0010] Beneficial effects: The material transition temperature (Tg) of polyurethane-based (SMP) is set at 50-60°C, and this material has the following advantageous properties:

[0011] Uniform shrinkage: During phase transition, the SMP material shrinks uniformly in volume (shrinkage rate can reach 5%-20%), rather than undergoing localized deformation;

[0012] Insulation: Non-conductive, non-magnetic, and will not interfere with chip operation;

[0013] Shape stability: It can maintain a fixed shape at room temperature and is not easily deformed by external forces or fluctuations in ambient temperature, which can effectively avoid the misalignment error caused by room temperature deformation.

[0014] This solution uses polyurethane-based (SMP) to make positioning plates. When the temperature is heated to Tg value or above, the positioning plates undergo a phase change and shrink. At this time, the shrunken positioning plates can be embedded into the limiting groove. When the temperature drops to room temperature, the positioning plates return to their original shape, achieving a transition fit between the positioning plates and the limiting groove.

[0015] Furthermore, the limiting plate is a steel sheet with several heat dissipation holes filled with heat dissipation material. By adding heat dissipation holes to the steel sheet and filling them with heat dissipation material, the heat transfer area between the steel sheet and the PCB rigid board is increased, which helps to improve heat dissipation performance.

[0016] Furthermore, a positioning part is provided on the surface of the rigid plate, and positioning holes are provided on the limiting plate and positioning piece respectively, with the positioning holes matching the positioning part.

[0017] Furthermore, the positioning part is screen-printed with ink, and the shape of the screen-printed ink matches the positioning hole. By using the positioning part and positioning hole, the installation position of the limiting plate and positioning piece can be determined during assembly by identifying the positional relationship between the positioning part and the positioning hole. This helps improve the installation accuracy between the limiting plate and positioning piece and the PCB rigid board, and reduces the attachment tolerance.

[0018] Furthermore, the limiting plate and the rigid plate are bonded together with a UV-curable adhesive, and the curing temperature of the UV-curable adhesive is adapted to the mass transition temperature of the positioning piece. By setting the curing temperature of the UV-curable adhesive to match the mass transition temperature of the positioning piece, the positioning piece can be heated simultaneously during UV curing, thereby reducing the size of the positioning piece and simplifying the assembly process.

[0019] Furthermore, the included angle between the limiting sidewall and the surface of the limiting plate is less than 90°, and the sidewall is inclined toward the PCB rigid board side that fixes the limiting plate. The included angle between the positioning piece sidewall and the top surface of the positioning piece is adapted to the included angle between the limiting sidewall and the surface of the limiting plate. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the unfolded state of an embodiment of the present utility model;

[0021] Figure 2 This is a schematic diagram of the folded state of an embodiment of the present invention;

[0022] Figure 3 This is a schematic diagram of the circuit board body according to an embodiment of the present utility model;

[0023] Figure 4 This is a schematic diagram of the limiting structure in Embodiment 1 of this utility model;

[0024] Figure 5 This is a schematic diagram of the limiting structure in Embodiment 2 of this utility model;

[0025] Figure 6 This is a schematic diagram of the limiting structure in Embodiment 3 of this utility model.

[0026] The reference numerals in the accompanying drawings include: first PCB rigid board 111, second PCB rigid board 112, flexible circuit board 113, positioning part 114, limiting plate 210, limiting groove 211, positioning piece 220, bonding surface 201, fixing surface 202, positioning outer edge 203, limiting side wall 204, positioning hole 205, and heat dissipation hole 206. Detailed Implementation

[0027] Example 1

[0028] Example 1 is basically as shown in the appendix. Figure 1-4 As shown, Figure 1-4 The rigid-flexible printed circuit board shown includes a circuit board body and a limiting structure, such as... Figure 3 As shown, the circuit board body includes at least two rigid PCBs. A flexible circuit board 113 is disposed between the two rigid PCBs and connects them to each other. The surfaces of the two rigid PCBs are respectively provided with ink screen printing as positioning parts 114. In this embodiment, the two rigid PCBs are respectively named a first rigid PCB 111 and a second rigid PCB 112. The flexible circuit board 113 is disposed between the first rigid PCB 111 and the second rigid PCB 112 and connects them.

[0029] The limiting structure includes a limiting plate 210 and a positioning piece 220, such as Figure 4 As shown, the limiting plate 210 is provided with a limiting groove 211, a positioning hole 205, and several heat dissipation holes 206. The size of the limiting groove 211 is adapted to the outer edge of the positioning piece, and the size of the positioning hole 205 is adapted to the positioning part 114. In this embodiment, both the limiting plate 210 and the positioning piece 220 are steel sheets. Both the limiting plate 210 and the positioning piece include a fixing surface 202 and a bonding surface 201. The limiting plate 210 is bonded to the surface of the first PCB rigid board through the fixing surface 202, and the positioning piece 220 is bonded to the surface of the second PCB rigid board 112 through the fixing surface. During assembly, firstly, a light-curing adhesive is applied to the fixing surface 202. The limiting plate 210 and the positioning piece are then bonded to the surfaces of the first PCB rigid board 111 and the second PCB rigid board 112 through the fixing surface 202, ensuring that the positioning hole is located on the positioning part, forming... Figure 1 The structure shown is used, and heat dissipation material is filled into the heat dissipation holes 206; finally, the flexible circuit board 113 is bent so that the mating surfaces 201 of the limiting plate 210 and the positioning piece are brought closer to each other until the outer edge 203 of the positioning piece is mated with the limiting sidewall 204, forming an interference fit, thereby clamping the first PCB rigid board onto the surface of the second PCB rigid board, forming as shown. Figure 2 The structure shown.

[0030] Example 2

[0031] Example 2 is basically the same as Example 1, except that the positioning piece 220 is made of a polyurethane-based material that can undergo thermal deformation, such as... Figure 5 As shown, during photocuring, the temperature is adjusted to the material transition temperature of the polyurethane base, causing the positioning piece to shrink. Subsequently, the shrunken positioning piece 220 is embedded in the limiting groove 211. When the temperature drops to room temperature, the positioning piece 220 returns to its original shape, achieving a transition fit between the positioning piece 220 and the limiting groove 211.

[0032] Example 3

[0033] Based on Example 2, such as Figure 6 As shown, the sidewall of the limiting groove 211 is the limiting sidewall 204, and the included angle between the limiting sidewall 204 and the mating surface 201 is less than 90°. The outer edge of the positioning piece 220 is the positioning outer edge. The included angle between the sidewall of the positioning piece 220 and the mating surface 201 of the positioning piece 220 is the same as the included angle between the limiting sidewall 204 and the surface of the limiting plate 210. During photocuring, the temperature is adjusted to the material transformation temperature of the polyurethane base, causing the positioning piece to shrink and embed the shrunken positioning piece into the limiting groove 211. When the temperature drops to room temperature, the positioning piece returns to its original shape, so that the limiting sidewall 204 and the positioning outer edge fit together to form a tenon and mortise structure, and realize the transition fit between the positioning piece and the limiting groove 211, thereby further improving the reliability of the limiting structure connection.

[0034] The above descriptions are merely embodiments of this utility model. Commonly known technical solutions and / or characteristics are not described in detail here. It should be noted that the technical means used to solve problems in the above embodiments of this utility model can be combined to solve multiple technical problems simultaneously. For those skilled in the art, several modifications and improvements can be made without departing from the technical solution of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A rigid-flex printed circuit board with a limiting structure, characterized by: The circuit board includes a circuit board body and a limiting structure. The circuit board body includes at least two rigid PCBs. A flexible circuit board is provided between the two rigid PCBs and the two rigid PCBs are connected to each other through the flexible circuit board. The limiting structure includes a limiting plate and a positioning piece. The limiting plate is provided with a limiting groove that matches the outer edge of the positioning piece. The limiting plate and the positioning piece are respectively fixed on the surface of the two rigid PCBs and can form an engaging structure through the cooperation of the positioning piece and the limiting groove.

2. A rigid-flex printed circuit board with a limiting structure according to claim 1, characterized in that: The positioning piece is made of polyurethane-based material that can undergo thermal deformation.

3. A rigid-flex printed circuit board with a limiting structure according to claim 2, wherein: The limiting plate is a steel sheet with several heat dissipation holes filled with heat dissipation material.

4. A rigid-flex printed circuit board with a limiting structure according to claim 3, wherein: The rigid plate surface is provided with a positioning part, and the limiting plate and positioning piece are respectively provided with positioning holes, which are adapted to the positioning part.

5. A rigid-flex printed circuit board with a limiting structure according to claim 4, wherein: The positioning part is screen-printed with ink, and the shape of the screen-printed ink is adapted to the positioning hole.

6. A rigid-flexible printed circuit board with a limiting structure according to claim 5, characterized in that: The limiting plate and the rigid plate are bonded together with UV-curable adhesive, and the curing temperature of the UV-curable adhesive is compatible with the material transition temperature of the positioning plate.

7. A rigid-flex printed circuit board with a limiting structure according to claim 6, wherein: The included angle between the limiting sidewall and the surface of the limiting plate is less than 90°, and the sidewall is inclined toward the PCB rigid board side that fixes the limiting plate. The included angle between the sidewall of the positioning piece and the top surface of the positioning piece is adapted to the included angle between the limiting sidewall and the surface of the limiting plate.

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