Welding structure of PCB (printed circuit board) hard board and FPC (flexible printed circuit) soft board

Abstract

The welding structure of the PCB hard board and the FPC soft board provided by the utility model comprises the PCB hard board and the FPC soft board, one end of the FPC soft board is transversely provided with a plurality of welding through holes with the same structure at equal intervals, the welding through holes penetrate through the upper end and the lower end of the FPC soft board, and the welding through holes are of an oval structure. A plurality of bonding pads of the same structure are transversely arranged on the surface of the side, facing the FPC flexible circuit board, of the PCB hard board at equal intervals and correspond to the welding through holes in position, solder paste layers are preset on the bonding pads to be welded and fixed to the welding through holes through the pulse thermocompression welding technology, and the solder paste layers penetrate through the welding through holes. According to the welding structure of the PCB hard board and the FPC soft board provided by the utility model, soldering tin connection is carried out by utilizing the welding through holes and the bonding pads, gaps between the through holes and the bonding pads can be fully filled, full and bright welding spots are formed, the welding spots can be visually seen from the outer surface of the circuit board, all the bonding pads are ensured to realize accurate welding, and the risk of pseudo soldering is reduced.

Description

Technical Field

[0001] This utility model relates to the field of circuit board technology, specifically a welding structure for a rigid PCB and a flexible FPC. Background Technology

[0002] FPC (Flexible Printed Circuit) is a type of flexible circuit board, often abbreviated as flex. PCB (Printed Circuit Board) is a type of rigid circuit board, often abbreviated as rigid. When connecting FPCs to PCBs, solder pads are provided on both boards, and they are then soldered together using a soldering machine or hot press. However, due to the use of solder pads, it's not immediately apparent whether all pads are connected after soldering, and the connection is not always secure, easily slipping off, directly leading to unstable electrical connections during subsequent product use. Utility Model Content

[0003] The purpose of this utility model is to provide a welding structure for rigid PCB boards and flexible FPC boards, and a crystal head using the protective sleeve, so as to solve the technical problems in the background art.

[0004] To achieve the aforementioned objectives, this utility model provides the following technical solution:

[0005] A welding structure for a rigid PCB and a flexible FPC includes a rigid PCB and a flexible FPC. One end of the flexible FPC has several identical welding through-holes arranged laterally at equal intervals. These through-holes penetrate both the top and bottom ends of the flexible FPC and are elliptical in shape. The surface of the rigid PCB facing the flexible FPC has several identical pads arranged laterally at equal intervals, corresponding to the positions of the welding through-holes. Solder paste layers are pre-placed on the pads and welded to the welding through-holes using a pulse thermoforming welding process. The solder paste layer passes through the welding through-holes.

[0006] The solder paste layer consists of individual raised arc-shaped bumps that cover the center of each individual pad.

[0007] The solder paste layer has a horizontal layer structure and covers all pads.

[0008] The dimensions of the solder pad are greater than or equal to the dimensions of the solder through-hole on the FPC flexible circuit board.

[0009] The upper and lower end faces of the FPC flexible circuit board are respectively covered with an insulating layer. The insulating layer avoids the solder through holes. The distance between the end face of the solder through hole and the insulating layer forms an elliptical connecting ring that contacts the solder paste layer.

[0010] Compared with the prior art, the welding structure of PCB rigid board and FPC flexible board provided by this utility model uses welding through holes to connect with pads for soldering. It can fully fill the gap between the through holes and the pads to form full and bright solder joints. The solder joints can be seen directly from the outer surface of the circuit board, ensuring that all pads are accurately soldered and reducing the risk of cold solder joints. Moreover, the welding structure of this application can solve the problem of solder bridging caused by insufficient spacing in traditional pad-to-pad soldering. The welding between PCB rigid board and FPC flexible board is more stable, ensuring the stability of the circuit connection between circuit boards. Attached Figure Description

[0011] Figure 1 : Schematic diagram of the PCB rigid board and FPC flexible circuit board structure in specific embodiment 1 of this application;

[0012] Figure 2 : Figure 1 Enlarged view of point A;

[0013] Figure 3 : A longitudinal cross-sectional view of a single welded through hole in specific embodiment 1 of this application;

[0014] Figure 4 : A schematic diagram of the welding structure of the PCB rigid board and the FPC flexible circuit board in specific embodiment 1 of this application;

[0015] Figure 5 : Schematic diagram of the PCB rigid board structure in specific implementation 2 of this application. Detailed Implementation

[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0017] Specific Implementation Example 1: Please refer to Figures 1 to 4 In this embodiment of the present invention, a welding structure of a PCB rigid board 3 and an FPC flexible board includes a PCB rigid board 3 and an FPC flexible circuit board 1. Several identical welding through holes 101 are arranged laterally at equal intervals at one end of the FPC flexible circuit board 1. The welding through holes 101 penetrate the upper and lower ends of the FPC flexible circuit board 1. The welding through holes 101 have an elliptical structure. Several identical solder pads 301 are arranged laterally at equal intervals on the surface of the PCB rigid board 3 facing the FPC flexible circuit board 1, corresponding to the positions of the welding through holes 101. The external dimensions of the solder pads 301 are greater than or equal to the dimensions of the welding through holes 101 on the FPC flexible circuit board 1. In this embodiment, the external dimensions of the solder pads 301 are equal to the dimensions of the welding through holes 101 on the FPC flexible circuit board 1.

[0018] A solder paste layer 4 is pre-placed on the pad 301 and is fixed to the soldering through-hole 101 by a pulse hot-press soldering process. The solder paste layer 4 passes through the soldering through-hole 101. In this embodiment, the solder paste layer 4 is a single raised arc bump structure that covers the center position of a single pad 301. The raised arc bump structure can achieve precise positioning and installation of the PCB rigid board 3 and the FPC flexible circuit board 1, allowing the arc bump to be inserted into the soldering through-hole 101, so that the positioning between the soldering through-hole 101 and the pad 301 is accurate. The raised solder paste has strong wettability after melting, which can fully fill the gap between the soldering through-hole 101 and the pad 301, forming a full and bright solder joint, making it less likely for the PCB rigid board 3 and the FPC flexible circuit board 1 to slip off, and making the soldering more firm.

[0019] The upper and lower end faces of the FPC flexible circuit board 1 are respectively covered with an insulating layer 2. The insulating layer 2 is used to protect the circuits on the end face of the FPC flexible circuit board 1. The insulating layer 2 avoids the soldering through hole 101. The distance between the end face of the soldering through hole 101 and the insulating layer 2 forms an elliptical connecting ring 102 that contacts the solder paste layer 4. In this embodiment, after the soldering through hole 101 on the FPC flexible circuit board 1 is inserted into the solder paste on the pad 301, the pad 301 is connected to the soldering through hole 101 through a pulse hot bar soldering process.

[0020] Specific Implementation Example 2: Please refer to Figure 5 Based on Example 1, the solder paste layer 4 is a horizontal layer structure that covers all pads 301. The processing efficiency of the solder paste layer 4 is faster, but the positioning between the PCB rigid board 3 and the FPC flexible circuit board 1 requires other auxiliary tooling for more precise positioning. There will be a slight deviation when positioning by human eye.

[0021] Compared with the prior art, the welding structure of PCB rigid board and FPC flexible board provided by this utility model uses welding through holes to connect with pads for soldering. It can fully fill the gap between the through holes and the pads to form full and bright solder joints. The solder joints can be seen directly from the outer surface of the circuit board, ensuring that all pads are accurately soldered and reducing the risk of cold solder joints. Moreover, the welding structure of this application can solve the problem of solder bridging caused by insufficient spacing in traditional pad-to-pad soldering. The welding between PCB rigid board and FPC flexible board is more stable, ensuring the stability of the circuit connection between circuit boards.

[0022] It will be apparent to those skilled in the art that this invention is not limited to the details of the foregoing exemplary embodiments, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0023] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A soldered structure of a PCB hard board and a FPC soft board, characterized by: The system includes a rigid PCB and a flexible printed circuit board (FPC). One end of the FPC has several identical solder through-holes arranged equidistantly in a horizontal direction. These through-holes penetrate both the top and bottom ends of the FPC and are elliptical in shape. The rigid PCB has several identical pads equidistantly arranged on one side of the FPC, corresponding to the positions of the solder through-holes. Solder paste layers are pre-placed on the pads and soldered to the through-holes using a pulsed thermoforming process. The solder paste layer passes through the solder through-holes.

2. The soldered structure of a PCB hard plate and a FPC soft plate according to claim 1, characterized in that: The solder paste layer consists of individual raised arc-shaped bumps that cover the center of each individual pad.

3. The welding structure of a rigid PCB and a flexible FPC according to claim 1, characterized in that: The solder paste layer has a horizontal layer structure and covers all pads.

4. A welding structure for a rigid PCB and a flexible FPC according to any one of claims 1-3, characterized in that: The dimensions of the solder pad are greater than or equal to the dimensions of the solder through-hole on the FPC flexible circuit board.

5. The welding structure of a rigid PCB and a flexible FPC according to claim 4, characterized in that: The upper and lower end faces of the FPC flexible circuit board are respectively covered with an insulating layer. The insulating layer avoids the solder through holes. The distance between the end face of the solder through hole and the insulating layer forms an elliptical connecting ring that contacts the solder paste layer.

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