A PCB interconnect structure for reducing carbon film resistance

Abstract

This application discloses a PCB interconnect structure for reducing carbon film resistance. The PCB interconnect structure for reducing carbon film resistance includes: a conductive carbon film and a substrate film; a copper foil contact assembly is disposed between the conductive carbon film and the substrate film; the copper foil contact assembly includes an upper copper foil and a lower copper foil, the upper copper foil being fixedly disposed at the conductive carbon film, and the lower copper foil being fixedly disposed at the substrate film. In order to solve the problem that the carbon film button produced by ordinary manufacturing process has a high carbon film resistance due to process problems in the prior art, this application designs a copper foil contact assembly. By setting the copper foil contact assembly, the conductivity of the conductive current can be effectively enhanced during use, and at the same time, a support structure is set to ensure the support gap between the conductive carbon film and the substrate film, thereby greatly reducing short circuits caused by accidental contact, and the use effect is better.

Description

Technical Field

[0001] This application relates to the field of carbon film button technology, and in particular to a PCB board interconnection structure for reducing the resistance of carbon film buttons. Background Technology

[0002] Carbon film buttons, as common electronic switching components, are widely used in electronic devices such as remote controls and instrument panels. Their traditional structure typically consists of a conductive carbon film layer printed on a flexible substrate. Conductivity is achieved by pressing the carbon film contacts against the underlying circuitry.

[0003] Carbon ink material itself has a high resistivity. At the same time, existing processing technology has problems such as uneven ink coverage and edge burrs during production and printing, which leads to generally high resistance values ​​of carbon film contacts, which seriously affects signal transmission quality and equipment sensitivity.

[0004] Meanwhile, the traditional carbon film lacks reliable physical isolation between itself and the substrate circuit, making it prone to accidental short circuits due to vibration or pressure; at the same time, the planar contact design limits the effective conductive area, further aggravating the on-resistance.

[0005] In other words, existing technologies suffer from the following technical problems: ordinary carbon film PCB boards have high contact resistance, which affects signal transmission quality and device sensitivity. Therefore, a PCB interconnection structure that reduces the resistance of carbon film is proposed to address these issues. Utility Model Content

[0006] This embodiment provides a PCB interconnection structure that reduces the carbon film resistance to solve the problem of high contact resistance in ordinary carbon film PCBs in the prior art, which affects signal transmission quality and device sensitivity.

[0007] According to one aspect of this application, a PCB interconnect structure for reducing carbon film resistance is provided, the PCB interconnect structure for reducing carbon film resistance includes:

[0008] Conductive carbon film and substrate film;

[0009] A copper foil contact assembly is provided between the conductive carbon film and the substrate film.

[0010] The copper foil contact assembly includes an upper copper foil and a lower copper foil. The upper copper foil is fixedly disposed on the conductive carbon film, and the lower copper foil is fixedly disposed on the substrate film.

[0011] Furthermore, the upper copper foil is electrically connected to the lower surface of the conductive carbon film by tightly adhering it to the conductive adhesive layer; the lower copper foil is formed on the upper surface of the substrate film by an etching process and is electrically connected to the external circuit.

[0012] Furthermore, the copper foil contact assembly also includes a support ring and a support sheet. The support ring is made of insulating material and is fixedly disposed on the upper surface of the substrate film.

[0013] Furthermore, a support piece is fixedly provided at one end of the side of the support ring, and the other end of the support piece is fixedly connected to the side of the upper copper foil.

[0014] Furthermore, a plurality of support plates are provided, and the plurality of support plates are arranged in a circular array.

[0015] Furthermore, the support sheet is made of an elastic material.

[0016] Furthermore, the upper copper foil and the lower copper foil have a matching three-dimensional combination structure on their opposite surfaces, which can increase the effective contact area when pressed.

[0017] Furthermore, the three-dimensional combined structure consists of a circular groove and a circular protrusion, with a circular groove at the center of the upper copper foil and a circular protrusion at the center of the lower copper foil.

[0018] Furthermore, the three-dimensional combined structure consists of peak-valley grooves and peak-valley protrusions. The bottom surface of the upper copper foil is provided with peak-valley grooves, and the upper surface of the lower copper foil is provided with peak-valley protrusions.

[0019] Furthermore, the three-dimensional combined structure consists of a wavy groove and a wavy protrusion. The bottom surface of the upper copper foil is provided with a wavy groove, and the upper surface of the lower copper foil is provided with a wavy protrusion.

[0020] In order to solve the problem of high carbon film resistance caused by process issues in carbon film buttons produced by ordinary manufacturing processes in the prior art, this application designs a copper foil contact component. By setting the copper foil contact component, the conductivity of electrical current can be effectively enhanced during use. At the same time, a support structure is set to ensure the support gap between the conductive carbon film and the substrate film, thereby greatly reducing short circuits caused by accidental contact and achieving better performance. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the overall structure of one embodiment of this application;

[0023] Figure 2 This is a cross-sectional three-dimensional structural diagram of one embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the structure of a copper foil contact assembly according to an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the structure of Embodiment 1 of the three-dimensional combined structure of this application;

[0026] Figure 5 This is a schematic diagram of the structure of Embodiment 2 of the three-dimensional combined structure of this application;

[0027] Figure 6 This is a schematic diagram of the structure of Embodiment 3 of the three-dimensional combined structure of this application.

[0028] In the picture:

[0029] 1. Conductive carbon film; 2. Substrate film;

[0030] Copper foil contact assembly 3, upper copper foil 301, support piece 302, support ring 303, lower copper foil 304;

[0031] Circular groove 305, circular protrusion 306, peak-valley groove 307, peak-valley protrusion 308, wavy groove 309, wavy protrusion 310. Detailed Implementation

[0032] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0033] Please see Figure 1-6 As shown, a PCB interconnect structure for reducing carbon film resistance is provided, the PCB interconnect structure for reducing carbon film resistance includes:

[0034] Conductive carbon film 1 and substrate film 2;

[0035] A copper foil contact assembly 3 is provided between the conductive carbon film 1 and the substrate film 2;

[0036] The copper foil contact assembly 3 includes an upper copper foil 301 and a lower copper foil 304. The upper copper foil 301 is fixedly disposed on the conductive carbon film 1, and the lower copper foil 304 is fixedly disposed on the substrate film 2.

[0037] Through the above technical solution, the copper foil contact component 3 can effectively enhance the conductivity of electrical current during use. At the same time, the support structure can ensure the support gap between the conductive carbon film 1 and the substrate film 2, thereby greatly reducing short circuits caused by accidental contact and achieving good performance.

[0038] Preferably, the conductive carbon film is a conductive material containing carbon particles, manufactured by a thin film process; the substrate film is a polyester film or a polyimide film, which has good mechanical and insulating properties. When the carbon film button is pressed, the upper conductive carbon film will contact the lower substrate film to form a current path.

[0039] The upper copper foil 301 is electrically connected to the lower surface of the conductive carbon film 1 by tightly adhering it to the conductive adhesive layer; the lower copper foil 304 is formed on the upper surface of the substrate film 2 by etching process and is electrically connected to the external circuit.

[0040] The copper foil contact assembly 3 also includes a support ring 303 and a support sheet 302. The support ring 303 is made of insulating material and is fixedly disposed on the upper surface of the substrate film 2.

[0041] Furthermore, the support ring 303 is injection molded from insulating epoxy resin, and its outer diameter is 1:1.2-1.5 to the diameter of the contact area of ​​the conductive carbon film 1, while the inner diameter forms a clearance space for the lower copper foil 304 to be exposed.

[0042] One end of the support piece 302 is fixedly disposed on the side of the support ring 303, and the other end of the support piece 302 is fixedly connected to the side of the upper copper foil 301.

[0043] The support plates 302 are provided in a plurality of manner, arranged in a circular array. Through this technical solution, the support plates 302 provide support for the upper copper foil 301, thereby creating a support gap between the upper copper foil 301 and the lower copper foil 304. This prevents accidental contact between the upper and lower copper foils 301 and 304 when not in use, thus improving operational stability.

[0044] The support sheet 302 is made of an elastic material. Through this technical solution, the support sheet 302 formed of elastic material allows the upper copper foil 301 to be automatically reset after being pressed by springback.

[0045] Specifically, the support piece 302 is a phosphor bronze sheet with a thickness of 0.05-0.1mm, and 4-8 pieces are evenly distributed along the circumference of the support ring 303. The cross-section of the support piece 302 is arched, and its apex is welded and fixed to the side of the upper copper foil 301. The arch height is 0.2-0.5mm, forming the support gap. The elastic support allows the upper copper foil 301 to contact and conduct with the lower copper foil 304 after a pressing stroke of 0.3mm, and automatically resets and separates after the pressure is released.

[0046] The upper copper foil 301 and the lower copper foil 304 are provided with a matching three-dimensional combination structure on their opposite surfaces, which can increase the effective contact area when pressed.

[0047] Example 1 of a three-dimensional combined structure:

[0048] Please see Figure 4 As shown:

[0049] The three-dimensional combined structure consists of a circular groove 305 and a circular protrusion 306. The circular groove 305 is provided at the center of the upper copper foil 301, and the circular protrusion 306 is provided at the center of the lower copper foil 304. Through this technical solution, when pressed, the upper copper foil 301 and the lower copper foil 304 come into contact, and the circular protrusion 306 is coupled with the circular groove 305, thereby increasing the conduction area and reducing the conduction resistance, and further reducing the resistance.

[0050] Example 2 of a three-dimensional combined structure:

[0051] Please see Figure 5 As shown:

[0052] The three-dimensional combined structure consists of a peak-valley groove 307 and a peak-valley protrusion 308. The peak-valley groove 307 is provided on the bottom surface of the upper copper foil 301, and the peak-valley protrusion 308 is provided on the upper surface of the lower copper foil 304. Through this technical solution, when pressed, the upper copper foil 301 and the lower copper foil 304 come into contact, and the peak-valley groove 307 and the peak-valley protrusion 308 engage, thereby increasing the contact area, increasing the conduction area, and reducing the conduction resistance.

[0053] Example 3 of a three-dimensional combined structure:

[0054] Please see Figure 6 As shown:

[0055] The three-dimensional combined structure consists of a wavy groove 309 and a wavy protrusion 310. The wavy groove 309 is provided on the bottom surface of the upper copper foil 301, and the wavy protrusion 310 is provided on the upper surface of the lower copper foil 304. Through this technical solution, when pressed, the upper copper foil 301 and the lower copper foil 304 come into contact, and the wavy groove 309 and the wavy protrusion 310 are combined, thereby increasing the contact area, increasing the conduction area, and reducing the conduction resistance.

[0056] In the actual manufacturing process, copper foil wires can be added to the K-claw carbon film button position to improve conductivity. Copper foil is added to the blank areas under the carbon film jumper. At the same time, the carbon film button and jumper are designed to run in a straight line to avoid poor printing ink application due to complex corners, resulting in high resistance.

[0057] The diameter of the copper foil at the base of the carbon film button is 1.0-1.5MM; the diameter of the copper foil conductor at the carbon film position of the K claw is 0.18-0.2MM; the width of the copper foil in the blank area under the carbon film jumper is 0.3-0.5MM; the carbon film button and jumper wiring adopts a straight-line design.

[0058] The circuits and electronic components involved are all existing technologies, and can be fully implemented by those skilled in the art.

[0059] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A PCB interconnect structure for reducing carbon film resistance, characterized in that: The PCB interconnect structure for reducing carbon film resistance includes: Conductive carbon film (1) and substrate film (2); A copper foil contact assembly (3) is provided between the conductive carbon film (1) and the substrate film (2). The copper foil contact assembly (3) includes an upper copper foil (301) and a lower copper foil (304). The upper copper foil (301) is fixedly disposed on the conductive carbon film (1), and the lower copper foil (304) is fixedly disposed on the substrate film (2).

2. The PCB interconnect structure for reducing carbon film resistance according to claim 1, characterized in that: The upper copper foil (301) is electrically connected to the lower surface of the conductive carbon film (1) by tightly adhering to the conductive adhesive layer; the lower copper foil (304) is formed on the upper surface of the substrate film (2) by etching process and is electrically connected to the external circuit.

3. The PCB interconnect structure for reducing carbon film resistance according to claim 1, characterized in that: The copper foil contact assembly (3) also includes a support ring (303) and a support sheet (302). The support ring (303) is made of insulating material and is fixedly disposed on the upper surface of the substrate film (2).

4. The PCB interconnect structure for reducing carbon film resistance according to claim 3, characterized in that: One end of a support piece (302) is fixedly provided on the side of the support ring (303), and the other end of the support piece (302) is fixedly connected to the side of the upper copper foil (301).

5. The PCB interconnect structure for reducing carbon film resistance according to claim 4, characterized in that: The support plate (302) is provided in a plurality of manner, and the plurality of support plates (302) are arranged in a ring array.

6. The PCB interconnect structure for reducing carbon film resistance according to claim 5, characterized in that: The support sheet (302) is made of an elastic material.

7. The PCB interconnect structure for reducing carbon film resistance according to claim 1, characterized in that: The upper copper foil (301) and the lower copper foil (304) are provided with a three-dimensional combination structure that matches each other, which is used to increase the effective contact area when pressed.

8. The PCB interconnect structure for reducing carbon film resistance according to claim 7, characterized in that: The three-dimensional combined structure consists of a circular groove (305) and a circular protrusion (306). The upper copper foil (301) has a circular groove (305) at its center, and the lower copper foil (304) has a circular protrusion (306) at its center.

9. The PCB interconnect structure for reducing carbon film resistance according to claim 7, characterized in that: The three-dimensional combined structure consists of a peak-valley groove (307) and a peak-valley protrusion (308). The bottom surface of the upper copper foil (301) is provided with a peak-valley groove (307), and the upper surface of the lower copper foil (304) is provided with a peak-valley protrusion (308).

10. The PCB interconnect structure for reducing carbon film resistance according to claim 7, characterized in that: The three-dimensional combined structure consists of a wavy groove (309) and a wavy protrusion (310). The bottom surface of the upper copper foil (301) is provided with a wavy groove (309), and the upper surface of the lower copper foil (304) is provided with a wavy protrusion (310).

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