Printed circuit board integrated structure

Abstract

The invention discloses a printed circuit board integrated structure which comprises a control printed circuit board and a switch printed circuit board. The size of the closed printed circuit board is smaller than that of the control printed circuit board; the control printed circuit board is not a carbon film printed circuit board manufactured by adopting a carbon film process, a control chip is welded on the surface of the control printed circuit board, and a plurality of control bonding pads are formed on the surface of the control printed circuit board; the switch printed circuit board is a carbon film printed circuit board, a reversing contact and a speed regulation carbon film track are formed on the front surface of the switch printed circuit board by adopting a carbon film process, and a pre-tinned switch bonding pad corresponding to the control bonding pad is formed; the pre-tinning switch bonding pad of the switch printed circuit board is welded with the corresponding control bonding pad of the control printed circuit board. The printed circuit board integrated structure is low in manufacturing cost, high in signal reliability and high in welding spot mechanical strength.

Description

Technical Field

[0001] This invention relates to printed circuit boards, and more particularly to an integrated structure for printed circuit boards. Background Technology

[0002] Currently, the connection architecture between signal switch modules and control boards in power tools mainly consists of two types of technical solutions: discrete PCB structure (dual-board solution) and single-board integrated architecture (common-board solution), both of which have significant technical defects.

[0003] The discrete PCB structure (dual-board solution) has defects in signal transmission path. In the discrete PCB structure (dual-board solution), the switch PCB (printed circuit board) and the control PCB are physically connected by soldered cables. The multi-level connection interface (such as solder joint-cable-solder joint) leads to increased contact resistance, causing signal voltage drop and affecting speed control accuracy. Solder joints and wire harness connectors have failed in vibration tests, causing intermittent open circuits and low mechanical reliability.

[0004] Single-board integrated architecture (common board solution) suffers from high manufacturing costs. In single-board integrated architecture (common board solution):

[0005] ● Carbon film printing requires specialized screen printing equipment. Due to equipment size limitations, the PCB panel size is forced to shrink. If large-size PCBs are used, the printing speed decreases and production efficiency drops significantly.

[0006] ● All metal pads on the entire PCB board need to be gold-plated, which significantly increases the cost;

[0007] ● Carbon film curing requires high-temperature reflow (peak temperature 250℃), and SMT (Surface Mount Technology) must be used again when placing electronic components, which increases energy consumption by 30% compared to conventional SMT processes.

[0008] Carbon film PCBs utilize carbon film technology to add one or two layers of conductive patterns to a single-sided printed circuit board, enabling high-density wiring. The printed conductive patterns serve not only as interconnects but also as resistors, push-button switch contacts, electromagnetic shielding layers, and more.

[0009] Carbon film coating is a common PCB manufacturing process. In PCB manufacturing, a copper foil layer is first deposited onto the substrate, then the copper foil is etched to form the circuit pattern. Next, a thin film of carbon material is applied to the conductive layer on the PCB surface through printing or vapor deposition to achieve circuit connection and protection. Carbon film coating offers good conductivity and chemical stability, effectively protecting the PCB from environmental corrosion while also enabling circuit connection and repair. It is suitable for applications requiring high circuit stability and reliability. Compared to other processes, carbon film coating offers lower cost and higher stability, but its manufacturing precision is relatively low, making it unsuitable for high-density PCBs. Furthermore, the application of carbon film coating in high-frequency and microwave circuits is somewhat limited. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a printed circuit board integrated structure that has low manufacturing cost, high signal reliability and high mechanical strength of solder joints.

[0011] To solve the above-mentioned technical problems, the present invention provides a printed circuit board integrated structure, which includes a control printed circuit board and a switch printed circuit board.

[0012] The size of the switch printed circuit board is smaller than the size of the control printed circuit board;

[0013] The control printed circuit board is not a carbon film printed circuit board manufactured using carbon film technology, and a control chip is soldered on its surface and multiple control pads are formed thereon.

[0014] The switch printed circuit board is a carbon film printed circuit board. It uses carbon film technology to form commutation contacts and speed-regulating carbon film tracks on the front side, and forms pre-tin-plated switch pads corresponding to the control pads.

[0015] The pre-tinned switch pads of the switch printed circuit board are soldered together with the corresponding control pads of the control printed circuit board.

[0016] Preferably, the thickness of the switch printed circuit board is less than the thickness of the control printed circuit board.

[0017] Preferably, the thickness of the control printed circuit board is 1.4mm to 2mm;

[0018] The thickness of the switch printed circuit board is 0.6mm to 1.0mm.

[0019] Preferably, the control printed circuit board has metal holes or vias.

[0020] Preferably, the control pad and the pre-tinned switch pad are rectangular.

[0021] Preferably, the pre-plated tin material of the pre-plated tin switch pad is an alloy of Sn, Ag and Cu.

[0022] Preferably, the pre-tinned switch pads and the corresponding control pads are soldered together using SMT.

[0023] Preferably, a reflow soldering process is used to solder the pre-tinned switch pads together with the corresponding control pads.

[0024] Preferably, the control printed circuit board uses an FR-4 substrate or a DBC substrate.

[0025] Preferably, the front side of the control printed circuit board has a plurality of control pads.

[0026] The switch printed circuit board has a pre-tinned switch pad on the back side that corresponds to the control pad.

[0027] The switch printed circuit board is vertically stacked and soldered to the front of the control printed circuit board, and the pre-tinned switch pads are soldered together with the corresponding control pads.

[0028] Preferably, a recessed area is formed by thinning one corner of the front side of the control printed circuit board;

[0029] The lateral contour of the recessed area is consistent with the lateral contour of the switch printed circuit board.

[0030] The front side of the control printed circuit board in the recessed area has multiple control pads.

[0031] The switch printed circuit board has pre-tinned switch pads on its back side that correspond to the control pads.

[0032] The switch printed circuit board is placed in the recessed area, and the pre-tinned switch pads are soldered together with the corresponding control pads, so that the switch printed circuit boards are vertically stacked and soldered to the front of the control printed circuit board.

[0033] Preferably, a cut-out area is formed at one corner of the control printed circuit board;

[0034] The lateral contour of the cutout area is consistent with the lateral contour of the switch printed circuit board.

[0035] Multiple control pads are formed on the sidewall of the hollowed-out area;

[0036] The switch printed circuit board has pre-tinned switch pads on its lateral side that correspond to the control pads.

[0037] The switch printed circuit board is embedded in the cutout area, and the pre-tinned switch pads are soldered together with the corresponding control pads, so that the switch printed circuit board is soldered into the cutout area of ​​the control printed circuit board.

[0038] The printed circuit board integration structure of this invention integrates a small-area switch printed circuit board using carbon film printed circuit boards with a large-area control printed circuit board that is not a carbon film printed circuit board. This breaks through the size limitations of integrated carbon film panel boards, improves production efficiency, eliminates the need for cables, connectors, and full-board immersion gold and gold plating processes, significantly reduces process and manufacturing costs, and achieves high-precision, low-cost integration of control printed circuit boards and switch printed circuit boards. It also eliminates signal attenuation and mechanical failure caused by welding cables in discrete structures, resulting in high signal reliability and high mechanical strength of solder joints. Attached Figure Description

[0039] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a perspective schematic diagram of an embodiment of the printed circuit board integrated structure of the present invention;

[0041] Figure 2 This is a front view of a control printed circuit board according to an embodiment of the printed circuit board integrated structure of the present invention.

[0042] Figure 3 This is a front view of a switch printed circuit board according to an embodiment of the printed circuit board integrated structure of the present invention.

[0043] Figure 4 This is a schematic diagram of the back of a switch printed circuit board according to an embodiment of the printed circuit board integrated structure of the present invention;

[0044] Figure 5 This is a perspective view of another embodiment of the printed circuit board integrated structure of the present invention;

[0045] Figure 6 This is a front view of a control printed circuit board according to another embodiment of the printed circuit board integrated structure of the present invention.

[0046] Figure 7 This is a front-side perspective view of a switch printed circuit board according to another embodiment of the printed circuit board integrated structure of the present invention;

[0047] Figure 8 This is a rear perspective view of a switch printed circuit board according to another embodiment of the printed circuit board integrated structure of the present invention.

[0048] Figure 9 This is a perspective view of another embodiment of the printed circuit board integrated structure of the present invention;

[0049] Figure 10 This is a front view of a control printed circuit board according to another embodiment of the printed circuit board integrated structure of the present invention.

[0050] Figure 11 This is a front and side perspective view of a switch printed circuit board according to another embodiment of the printed circuit board integrated structure of the present invention.

[0051] Explanation of reference numerals in the attached figures:

[0052] 1 Control printed circuit board; 10 Control pads; 15 Recessed area; 16 Cut-out area; 2 Switch printed circuit board; 20 Pre-tinned switch pads; 21 Speed-regulating carbon film track. Detailed Implementation

[0053] The technical solutions of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0054] Example 1

[0055] A printed circuit board integrated structure, such as Figure 1 , Figure 5 and Figure 9 As shown, it includes a control printed circuit board 1 and a switch printed circuit board 2.

[0056] The size of the switch printed circuit board 2 is smaller than the size of the control printed circuit board 1;

[0057] The control printed circuit board 1 is not a carbon film printed circuit board manufactured using carbon film technology, and a control chip is soldered on its surface and multiple control pads 10 are formed thereon.

[0058] like Figure 3 , Figure 4 , Figure 7 , Figure 8 and Figure 11 As shown, the switch printed circuit board 2 is a carbon film printed circuit board. It uses carbon film technology to form commutation contacts and speed-regulating carbon film tracks 21 on the front side, and forms pre-tin-plated switch pads 20 corresponding to the control pads 10.

[0059] The pre-tinned switch pads 20 of the switch printed circuit board 2 are soldered together with the corresponding control pads 10 of the control printed circuit board 1.

[0060] The implementation of a single-phase printed circuit board (PCB) integrated structure integrates a small-area switch PCB 2 (using carbon film PCB) with a large-area control PCB 1 (not using carbon film PCB). This overcomes the size limitations of integrated carbon film PCB panels, improves production efficiency, eliminates the need for cables, connectors, and full-board immersion gold plating, significantly reducing process and manufacturing costs. It achieves high-precision, low-cost integration of the control PCB 1 and switch PCB 2, eliminating signal attenuation and mechanical failure caused by soldered cables in discrete structures, resulting in high signal reliability and high solder joint mechanical strength. This PCB integrated structure is particularly suitable as a signal switch for power tool switches and a control module for main control.

[0061] Example 2

[0062] Based on the printed circuit board integration structure of Embodiment 1, the thickness of the switch printed circuit board 2 is less than the thickness of the control printed circuit board 1.

[0063] Preferably, the thickness of the control printed circuit board 1 is 1.4 mm to 2 mm (e.g., 1.6 mm).

[0064] Preferably, the thickness of the switch printed circuit board 2 is 0.6 mm to 1.0 mm (e.g., 0.8 mm).

[0065] Preferably, the control printed circuit board 1 has metal vias or through-holes. The metal vias are formed by depositing a conductive metal layer on the insulating hole wall of the printed circuit board through chemical plating or electroplating, and are used to interconnect the wires of each layer.

[0066] Preferably, the control pad 10 and the pre-tinned switch pad 20 are rectangular.

[0067] Preferably, the pre-plated tin material of the pre-plated tin switch pad 20 is an alloy of Sn, Ag and Cu, which can ensure a welding strength >25MPa.

[0068] Example 3

[0069] Based on the printed circuit board integrated structure of Embodiment 1, the pre-tinned switch pad 20 and the corresponding control pad are soldered together using SMT (Surface Mount Technology).

[0070] Preferably, laser positioning and reflow soldering processes are used to control the precise alignment (tolerance ±0.05mm) of the printed circuit board 1 and the switch printed circuit board 2, and to solder the pre-tinned switch pad 20 to the corresponding control pad 10 together. The reflow soldering process is part of SMT (Surface Mount Technology).

[0071] The printed circuit board integration structure in Example 3 uses a small-area switch printed circuit board 2 made of carbon film printed circuit board as a component. It can be perfectly compatible with the SMT production line through SMT removal and does not require additional fixtures.

[0072] Example 4

[0073] Based on the printed circuit board integration structure of Embodiment 1, the control printed circuit board 1 adopts an FR-4 substrate or a DBC (direct bonded copper ceramic) substrate. Epoxy board (FR-4) is a composite material made of epoxy resin as the base material and by adding auxiliary materials such as curing agents and fillers. Epoxy board (FR-4) is characterized by high mechanical and dielectric properties, good heat and moisture resistance, and good machinability.

[0074] Preferably, the FR-4 substrate is multilayered (e.g., 4-layered).

[0075] The printed circuit board integration structure of Example 4 adopts a "pad + support" composite structure. The support is a control printed circuit board made of FR-4 material or ceramic material. The switch printed circuit board 2 is soldered and integrated with the control printed circuit board 1, resulting in high mechanical strength.

[0076] Example 5

[0077] Based on the printed circuit board integration structure of Embodiment 1, such as Figure 2 As shown, a plurality of control pads 10 are formed on the front side of the control printed circuit board 1.

[0078] like Figure 4 As shown, the switch printed circuit board 2 has a pre-tinned switch pad 20 on the back side that corresponds to the control pad 10.

[0079] The switch printed circuit board 2 is vertically stacked and soldered to the front side of the control printed circuit board 1, and the pre-tinned switch pad 20 is soldered together with the corresponding control pad 10.

[0080] In the printed circuit board integration structure of Example 5, the switch printed circuit board 2 and the control printed circuit board 1 are vertically stacked and soldered together, resulting in a small area and high mechanical strength.

[0081] Example 6

[0082] Based on the printed circuit board integration structure of Embodiment 1, such as Figure 6 As shown, a recessed area 15 is formed by thinning the front side of one corner of the control printed circuit board 1;

[0083] The lateral contour of the recessed area 15 is consistent with the lateral contour of the switch printed circuit board 2.

[0084] The front side of the control printed circuit board 1 in the recessed area 15 has a plurality of control pads 10.

[0085] like Figure 8 As shown, the switch printed circuit board 2 has a pre-tinned switch pad 20 on the back side that corresponds to the control pad 10.

[0086] The switch printed circuit board 2 is placed in the recessed area 15, and the pre-tinned switch pad 20 is soldered together with the corresponding control pad 10, so that the switch printed circuit board 2 is vertically stacked and soldered on the front side of the control printed circuit board 1.

[0087] Example 7

[0088] Based on the printed circuit board integration structure of Embodiment 1, such as Figure 10 As shown, a cutout area 16 is formed at one corner of the control printed circuit board 1;

[0089] The lateral contour of the cutout area 16 is consistent with the lateral contour of the switch printed circuit board 2.

[0090] Multiple control pads 10 are formed on the sidewall of the hollowed-out area 16;

[0091] like Figure 11 As shown, the switch printed circuit board 2 has a pre-tinned switch pad 20 corresponding to the control pad 10 formed on its lateral side.

[0092] The switch printed circuit board 2 is embedded in the cutout area 16, and the pre-tinned switch pad 20 is soldered together with the corresponding control pad 10, so that the switch printed circuit board 2 is soldered into the control printed circuit board.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A printed circuit board integrated structure, characterized in that, It includes a control printed circuit board (1) and a switch printed circuit board (2); The size of the switch printed circuit board (2) is smaller than the size of the control printed circuit board (1); The control printed circuit board (1) is not a carbon film printed circuit board manufactured using carbon film technology, and a control chip is soldered on its surface and multiple control pads (10) are formed thereon. The switch printed circuit board (2) is a carbon film printed circuit board. It uses carbon film technology to form commutation contacts and speed-regulating carbon film tracks (21) on the front side, and forms pre-plated tin switch pads (20) corresponding to the control pads (10). The pre-tinned switch pads (20) of the switch printed circuit board (2) are soldered together with the corresponding control pads (10) of the control printed circuit board (1).

2. The printed circuit board integrated structure according to claim 1, characterized in that, The thickness of the switch printed circuit board (2) is less than the thickness of the control printed circuit board (1).

3. The printed circuit board integrated structure according to claim 2, characterized in that, The thickness of the control printed circuit board (1) is 1.4mm to 2mm; The thickness of the switch printed circuit board (2) is 0.6mm to 1.0mm.

4. The printed circuit board integrated structure according to claim 1, characterized in that, The control printed circuit board (1) has metal holes or vias formed.

5. The printed circuit board integrated structure according to claim 1, characterized in that, The control pad (10) and the pre-tinned switch pad (20) are rectangular.

6. The printed circuit board integrated structure according to claim 1, characterized in that, The pre-plated tin material of the pre-plated tin switch pad (20) is an alloy of Sn, Ag and Cu.

7. The printed circuit board integrated structure according to claim 1, characterized in that, The pre-tinned switch pad (20) is soldered together with the corresponding control pad using SMT.

8. The printed circuit board integrated structure according to claim 6, characterized in that, The pre-tinned switch pad (20) is soldered together with the corresponding control pad (10) using a reflow soldering process.

9. The printed circuit board integrated structure according to claim 1, characterized in that, The control printed circuit board (1) uses an FR-4 substrate or a DBC substrate.

10. The printed circuit board integrated structure according to claim 1, characterized in that, The control printed circuit board (1) has multiple control pads (10) formed on its front side; The switch printed circuit board (2) has a pre-plated tin switch pad (20) on its back side that corresponds to the control pad (10); The switch printed circuit board (2) is vertically stacked and soldered to the front side of the control printed circuit board (1), and the pre-tinned switch pad (20) is soldered together with the corresponding control pad (10).

11. The printed circuit board integrated structure according to claim 1, characterized in that, A recessed area (15) is formed by thinning one corner of the front side of the control printed circuit board (1); The lateral contour of the recessed area (15) is consistent with the lateral contour of the switch printed circuit board (2); The front side of the control printed circuit board (1) in the recessed area (15) has multiple control pads (10); The switch printed circuit board (2) has a pre-plated tin switch pad (20) on its back side that corresponds to the control pad (10); The switch printed circuit board (2) is placed in the recessed area (15), and the pre-plated tin switch pad (20) is soldered together with the corresponding control pad (10), so that the switch printed circuit board (2) is vertically stacked and soldered on the front side of the control printed circuit board (1).

12. The printed circuit board integrated structure according to claim 1, characterized in that, A cutout area (16) is formed at one corner of the control printed circuit board (1); The lateral contour of the cutout area (16) is consistent with the lateral contour of the switch printed circuit board (2); The sidewall of the hollowed-out area (16) is formed with a plurality of control pads (10); The switch printed circuit board (2) has a pre-plated tin switch pad (20) on its lateral side, which corresponds to the control pad (10). The switch printed circuit board (2) is embedded in the cutout area (16), and the pre-tinned switch pad (20) is soldered together with the corresponding control pad (10), so that the switch printed circuit board (2) is soldered in the cutout area (16) of the control printed circuit board (1).

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