Double-layer flexible circuit board

Abstract

The invention discloses a double-layer flexible circuit board, and belongs to the technical field of flexible circuit boards, the double-layer flexible circuit board comprises a circuit board main body, the front and rear ends of the top and bottom of the circuit board main body are respectively provided with an elastic steel sheet, and the two ends of the circuit board main body are respectively and fixedly connected with an insertion reinforcing assembly; a stretching positioning assembly is mounted in the middle of the circuit board main body, and the circuit board main body is wound on the stretching positioning assembly in an S shape; the top and the bottom of the stretching positioning assembly are fixedly provided with mobile limiting assemblies which are used for limiting the folding part of the circuit board main body. An elastic reset mechanism is installed on one side of the stretching positioning assembly in a sliding mode. By designing an adjustable structure, the double-layer flexible circuit board can have better adaptability and adjustability, the circuit board main body can realize rolling friction in the unfolding and resetting processes, disordered repeated wear and excessive folding are avoided, and the service life of the double-layer flexible circuit board is further ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of flexible circuit boards, and in particular relates to a double-layer flexible circuit board. Background Art

[0002] A double-layer flexible circuit board is a circuit board composed of two layers of conductive copper foil and a flexible substrate (such as polyimide, etc.). It has the characteristics of both flexible and multi-layer circuit design and is widely used in electronic devices, especially in environments where space is limited and bending or folding is required, such as consumer electronics, communication equipment, and medical electronic products. Double-layer flexible circuit boards usually have the following structure: Flexible substrate: usually polyimide (PI) or polyester (PET) materials are used, which have good flexibility, heat resistance and electrical insulation properties; Copper foil layer: double-sided copper-clad design, usually with two layers of copper foil, one of which is the main circuit layer, and the other is used for connection and supplementary wiring; Solder mask and marking layer: similar to traditional rigid PCBs, they can be used to protect circuits, prevent short circuits or other external damage, and provide circuit identification.

[0003] Double-layer flexible circuit boards are a very common type of circuit board on the market. Due to their excellent characteristics, they are widely used in many fields. However, the existing double-layer flexible circuit boards still have certain defects when used in different occasions, such as Fig.16 As shown, the existing double-layer flexible circuit boards generally adopt a fixed structure according to the design requirements of the actual use equipment, and their length is also designed to be fixed according to the longest path. When the circuit board is used for the line connection of a foldable device, since the foldable device has a certain bending path, when the foldable device is reset from a bent state, the circuit board with a fixed path length will have a residual protrusion. Whenever the foldable device is bent and reset, this part of the protrusion will produce disordered repeated friction with the internal parts of the device, and even excessive folding will occur. Over time, it is easy to cause damage to the flexible circuit board, thereby affecting the normal operation of the device. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the disadvantages of the above-mentioned prior art and provide a double-layer flexible circuit board.

[0005] The technical solution adopted to solve the above technical problems is: a double-layer flexible circuit board, comprising a circuit board body, the front and rear ends of the top and bottom of the circuit board body are provided with elastic steel sheets, and both ends of the circuit board body are fixedly connected with plug-in reinforcement components;

[0006] A stretching and positioning component is installed in the middle of the circuit board body, and the circuit board body is wound around the stretching and positioning component in an S shape;

[0007] The top and bottom of the stretching and positioning assembly are fixedly mounted with movable limiting assemblies for limiting the folding portion of the circuit board body;

[0008] An elastic reset mechanism is slidably mounted on one side of the stretching and positioning assembly, and is used for automatic reset of the circuit board body after being stretched.

[0009] Furthermore, the circuit board body includes a substrate layer, and a plurality of evenly distributed copper wires are provided on the top and bottom of the substrate layer, and insulating films are attached to the outer sides of the upper and lower groups of copper wires.

[0010] Through the above technical solution, the circuit board body serves as the main structure and mainly plays the function of connecting the circuits. A plurality of evenly distributed copper wires are provided on the top and bottom of the substrate layer. Each copper wire can be used as an independent wire to connect the corresponding circuit to realize the electrical connection of the application equipment circuit. An insulating film is attached to the outside of the copper wire, which can play both an insulating and protective role.

[0011] Furthermore, the plurality of elastic steel sheets are respectively attached to the front and rear ends of the top and bottom of the substrate layer.

[0012] Through the above technical solution, by compounding multiple elastic steel sheets on the circuit board body, the overall tensile strength of the circuit board body can be improved, and at the same time, it can also provide better protection during the folding or reciprocating movement of the circuit board body, thereby preventing the circuit board body from being broken or damaged due to long-term reciprocating folding.

[0013] Furthermore, the plug-in reinforcement component includes a reinforcement plate fixed to the end of the circuit board body, and the top and bottom of the reinforcement plate are provided with a plurality of evenly distributed copper plug-in pins, and each of the copper plug-in pins is electrically connected to the circuit board body through a welding portion.

[0014] Through the above technical solution, the plug-in reinforcement component is mainly used as the plug-in part between the end of the circuit board body and the connection port. By designing the reinforcement plate, the overall strength of the connection parts at both ends of the circuit board body can be further improved. In addition, by setting copper plug-in pins corresponding to the circuit board body, the electrical connection between the two can be achieved. When the plug-in reinforcement component is plugged into the wiring port of the application equipment, fast and stable equipment connection can be achieved.

[0015] Furthermore, the stretching positioning assembly includes two positioning brackets installed at the front and rear ends of the circuit board body, and the two sides between the two positioning brackets are respectively rotatably connected with the first positioning shaft and the second positioning shaft, the circuit board body is S-shaped and passes through the two groups of first positioning shafts and second positioning shafts, and two first mounting holes are provided on the top and bottom of the outer sides of the two positioning brackets.

[0016] Through the above technical scheme, the stretching positioning assembly is mainly used for winding and positioning of the circuit board body. During assembly, the circuit board body can be bent into an S shape in cooperation with the elastic reset mechanism. At this time, due to the further limiting of the two sets of first positioning shafts and the second positioning shafts, the circuit board body can always maintain the S-shaped bending structure, so as to facilitate the smooth adjustment of the circuit board body during the bending or resetting process of the application equipment, and there will be no residual protrusion of the circuit board body during the resetting process due to the path length problem, thereby ensuring the stability of the circuit board body during use. In addition, since the two sets of first positioning shafts and the second positioning shaft are rotatably connected between the two positioning brackets, the circuit board body can achieve rolling friction during the unfolding and resetting process, and will not produce disordered repeated wear and excessive folding.

[0017] Furthermore, a first through hole is formed in the middle of the two positioning brackets.

[0018] Furthermore, the movable limit assembly includes two limit rods distributed longitudinally in parallel, a limit plate is fixedly connected between the two limit rods, a second through hole is opened in the middle of the limit plate, and the front and rear ends of the two limit rods are fixedly connected with mounting seats, and the multiple mounting seats are fixed to the corresponding first mounting holes by first fixing screws.

[0019] Through the above technical scheme, the movable limiting component is mainly used for further limiting the circuit board body in the bent state. The movable limiting component cooperates with the stretching positioning component to ensure that the circuit board body is always in an S-shaped bent state. In addition, by setting two longitudinally parallel limiting rods, the friction can be reduced when the limiting rods contact the circuit board body, thereby further protecting the circuit board body.

[0020] Furthermore, a group of movable limiting components located at the bottom are also fixedly connected to a plurality of fixing seats.

[0021] Through the above technical solution, by setting multiple fixed seats on a group of movable limit assemblies below, the movable limit assemblies can be connected to the application equipment through screws to achieve the installation and fixation of the stretching positioning assembly and the elastic reset mechanism to ensure its stability during operation.

[0022] Furthermore, the elastic reset mechanism includes a reset guide rail fixed to one side of the two positioning brackets, a limiting slide groove is provided in the two reset guide rails, a second mounting hole is provided on the side of the two reset guide rails away from the positioning bracket, a serpentine spring is installed in the two limiting slide grooves, a reset guide rod is slidably installed in the two limiting slide grooves, a limiting hole is provided in the middle of the two reset guide rods, one end of the two reset guide rods away from the positioning bracket is fixedly connected to a rotating seat, a first limiting rotating shaft and a second limiting rotating shaft are rotatably connected between the two rotating seats, and the circuit board body passes through the first limiting rotating shaft and the second limiting rotating shaft and bypasses the second limiting rotating shaft.

[0023] Through the above technical scheme, the elastic reset mechanism is an important component in the process of unfolding and resetting the circuit board body. Since the circuit board body runs through the first limit rotating shaft and the second limit rotating shaft, when the folding part of the application device begins to bend, one end of the circuit board body will follow the active end of the device to be stretched synchronously, so that the active circuit board body will further drive the first limit rotating shaft and the second limit rotating shaft to move in the direction of the stretching positioning component, thereby driving the two reset guide rods to slide in the corresponding limit sliding grooves and squeeze the corresponding serpentine springs, so that the circuit board body can always maintain a relatively tensioned state; when the device is reset from the bent state, since the active end of the circuit board body slowly loses the traction tension, at this time, under the action of the rebound force of the two serpentine springs, the first limit rotating shaft and the second limit rotating shaft will push the circuit board body in the opposite direction to move and fold and shrink, so that the circuit board body can always maintain a relatively stable tensioned state without the occurrence of excess bulges.

[0024] Furthermore, the two second mounting holes are both threadedly connected with second fixing screws for limiting the movement of the reset guide rod.

[0025] Through the above technical solution, by providing the second fixing screw, it is possible to play an auxiliary limiting role in the movement of the reset guide rod, and at the same time, it is also possible to prevent the reset guide rod from detaching from the positioning bracket.

[0026] The beneficial effects of the present invention are as follows: (1) The present invention can improve the overall tensile strength of the circuit board body by designing an elastic steel sheet, and can also play a better protective function during the folding or reciprocating movement of the circuit board body, so as to prevent the circuit board body from being broken or damaged due to long-term reciprocating folding; (2) The present invention can make the circuit board body always maintain an S-shaped bending structure by designing a stretching positioning component, a movable limit component and an elastic reset mechanism, so that the circuit board body can be smoothly adjusted during the bending or resetting process of the application equipment, and there will be no residual protrusion of the circuit board body during the resetting process due to the path length problem, thereby ensuring the stability of the circuit board body during use; (3) The present invention can make the double-layer flexible circuit board have better adaptability and adjustability by designing an adjustable structure, and the circuit board body can achieve rolling friction during the unfolding and resetting process, and will not produce disordered repeated wear and excessive folding, thereby ensuring its service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a first perspective structural diagram of the present invention;

[0028] Figure 2 It is a second viewing angle structural diagram of the present invention;

[0029] Figure 3 It is a third perspective structural diagram of the present invention;

[0030] Figure 4 yes Figure 3 A partial enlarged view of the middle A;

[0031] Figure 5 yes Figure 3 A partial enlarged view of point B in the middle;

[0032] Figure 6 It is a front view of the present invention;

[0033] Figure 7 is a top view of the present invention;

[0034] Figure 8 It is a structural schematic diagram of the circuit board body of the present invention;

[0035] Fig. 9 It is a front view of the circuit board body of the present invention;

[0036] Fig.10 is a cross-sectional view of the circuit board body of the present invention;

[0037] Fig.11 This is a structural diagram of the movable limit assembly and the elastic reset mechanism of the present invention from a first perspective;

[0038] Fig.12 yes Fig.11 A partial enlarged view of point C in the middle;

[0039] Fig.13 It is a structural diagram of the movable limit assembly and the elastic reset mechanism of the present invention from a second viewing angle;

[0040] Fig.14 It is a structural schematic diagram of the stretching positioning assembly of the present invention;

[0041] Fig.15 It is a schematic diagram of the structure of the stretching positioning assembly and the elastic reset mechanism of the present invention;

[0042] Fig.16 This is a diagram showing the changes in the usage status of existing flexible circuit boards for bendable devices.

[0043] Reference numerals: 1. circuit board body; 101. substrate layer; 102. copper wire; 103. insulating film; 2. elastic steel sheet; 3. plug-in reinforcement component; 301. reinforcement plate; 302. copper plug-in pin; 303. welding part; 4. stretching positioning component; 401. positioning bracket; 402. first positioning shaft; 403. second positioning shaft; 404. first through hole; 405. first mounting hole; 5. moving limit component; 501 , limit rod; 502, limit plate; 503, second through hole; 504, mounting seat; 505, first fixing screw; 506, fixing seat; 6, elastic reset mechanism; 601, reset guide rail; 602, limit slide groove; 603, second mounting hole; 604, serpentine spring; 605, reset guide rod; 606, limit hole; 607, second fixing screw; 608, rotating seat; 609, first limit rotating shaft; 610, second limit rotating shaft. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0045] like Figure 1-Figure 15As shown, a double-layer flexible circuit board of the present embodiment includes a circuit board body 1, the circuit board body 1 includes a substrate layer 101, a plurality of evenly distributed copper wires 102 are provided on the top and bottom of the substrate layer 101, and an insulating film 103 is attached to the outer sides of the upper and lower groups of copper wires 102. The circuit board body 1 serves as a main structure and mainly serves the function of connecting the circuits. A plurality of evenly distributed copper wires 102 are provided on the top and bottom of the substrate layer 101, and each copper wire 102 can be used as an independent wire to connect the corresponding circuit to realize the electrical connection of the application equipment circuit. An insulating film 103 is attached to the outer side of the copper wire 102, which can play both an insulating role and a protective role.

[0046] Regarding the elastic steel sheet 2, refer to Figure 1-Figure 10 Elastic steel sheets 2 are provided at the front and rear ends of the top and bottom of the circuit board body 1, and multiple elastic steel sheets 2 are respectively attached to the front and rear ends of the top and bottom of the substrate layer 101. By compounding multiple elastic steel sheets 2 on the circuit board body 1, the overall tensile strength of the circuit board body 1 can be improved, and at the same time, it can also play a better protective function during the folding or reciprocating movement of the circuit board body 1, so as to prevent the circuit board body 1 from being broken or damaged due to long-term reciprocating folding.

[0047] For the plug-in reinforcement component 3, refer to Figure 1-Figure 4 , both ends of the circuit board body 1 are fixedly connected with a plug-in reinforcement component 3; the plug-in reinforcement component 3 includes a reinforcement plate 301 fixed to the end of the circuit board body 1, and the top and bottom of the reinforcement plate 301 are provided with a plurality of evenly distributed copper plug pins 302, and each copper plug pin 302 is electrically connected to the circuit board body 1 through a welding portion 303. The plug-in reinforcement component 3 mainly serves as a plug-in portion between the end of the circuit board body 1 and the connection port. By designing the reinforcement plate 301, the overall strength of the connection parts at both ends of the circuit board body 1 can be further improved. In addition, by setting the copper plug pins 302 corresponding to the circuit board body 1, the electrical connection between the two can be achieved. When the plug-in reinforcement component 3 is plugged into the wiring port of the application device, a fast and stable device connection can be achieved.

[0048] For stretch positioning component 4, refer to Figure 11-Figure 15A stretching positioning component 4 is installed in the middle of the circuit board body 1, and the circuit board body 1 is wound on the stretching positioning component 4 in an S shape; the stretching positioning component 4 includes two positioning brackets 401 installed at the front and rear ends of the circuit board body 1, and the two sides between the two positioning brackets 401 are respectively rotatably connected with a first positioning shaft 402 and a second positioning shaft 403, and the circuit board body 1 is S-shaped and runs through the two groups of first positioning shafts 402 and second positioning shafts 403. The middle of the two positioning brackets 401 is provided with a first through hole 404, and the top and bottom of the outer sides of the two positioning brackets 401 are provided with two first mounting holes 405. The stretching positioning component 4 is mainly used for winding and positioning of the circuit board body 1, and can cooperate with the elastic reset mechanism during assembly. 6 The circuit board body 1 is bent into an S shape. At this time, due to the further limitation of the two groups of first positioning shafts 402 and the second positioning shafts 403, the circuit board body 1 can always maintain the S-shaped bending structure, so that the circuit board body 1 can be smoothly adjusted during the bending or resetting process of the application equipment, and there will be no residual protrusion of the circuit board body 1 during the resetting process due to the path length problem, thereby ensuring the stability of the circuit board body 1 during use. In addition, since the two groups of first positioning shafts 402 and the second positioning shafts 403 are rotatably connected between the two positioning brackets 401, the circuit board body 1 can achieve rolling friction during the unfolding and resetting process, and will not produce disordered repeated wear and excessive folding.

[0049] For the mobile limiter assembly 5, refer to Fig.11 and Fig.15 , the top and bottom of the stretching positioning component 4 are fixedly installed with a movable limiting component 5 for limiting the folding portion of the circuit board body 1; the movable limiting component 5 includes two longitudinally parallel limiting rods 501, a limiting plate 502 is fixedly connected between the two limiting rods 501, a second through hole 503 is opened in the middle of the limiting plate 502, the front and rear ends of the two limiting rods 501 are fixedly connected with mounting seats 504, and multiple mounting seats 504 are fixed to the corresponding first mounting holes 405 by first fixing screws 505. The movable limiting component 5 is mainly used for further limiting the circuit board body 1 in the bending state. The movable limiting component 5 cooperates with the stretching positioning component 4 to ensure that the circuit board body 1 is always in an S-shaped bending state. In addition, by setting two longitudinally parallel limiting rods 501, the friction between the limiting rods 501 and the circuit board body 1 can be reduced, thereby further protecting the circuit board body 1.

[0050] Furthermore, in this embodiment, a plurality of fixed seats 506 are fixedly connected to a group of movable limit assemblies 5 located below. By setting a plurality of fixed seats 506 on the group of movable limit assemblies 5 located below, the movable limit assemblies 5 can be connected to the application equipment through screws to achieve the installation and fixation of the stretching positioning assembly 4 and the elastic reset mechanism 6 to ensure their stability during operation.

[0051] Regarding the elastic reset mechanism 6, refer to Figure 11-Figure 15 , an elastic reset mechanism 6 is slidably installed on one side of the stretching positioning component 4, which is used for automatic reset of the circuit board body 1 after stretching; the elastic reset mechanism 6 includes a reset rail 601 fixed to one side of the two positioning brackets 401, and the two reset rails 601 are provided with a limited sliding groove 602, and the two reset rails 601 are provided with a second mounting hole 603 on the side away from the positioning bracket 401, and the two limited sliding grooves 602 are both installed with a serpentine spring 604, and the two limited sliding grooves 602 are both slidably installed. There are reset guide rods 605, and the middle parts of the two reset guide rods 605 are provided with limited holes 606. The ends of the two reset guide rods 605 away from the positioning bracket 401 are fixedly connected with a rotating seat 608. The two rotating seats 608 are respectively rotatably connected with a first limited rotation shaft 609 and a second limited rotation shaft 610. The circuit board body 1 runs through the first limited rotation shaft 609 and the second limited rotation shaft 610 and bypasses the second limited rotation shaft 610. The elastic reset mechanism 6 is the circuit board body 1. The circuit board body 1 is an important part of the process. Since the circuit board body 1 runs through the first limit rotating shaft 609 and the second limit rotating shaft 610, when the folding part of the application device begins to bend, one end of the circuit board body 1 will follow the active end of the device to be stretched synchronously, so that the active circuit board body 1 will further drive the first limit rotating shaft 609 and the second limit rotating shaft 610 to move in the direction of the stretching positioning component 4, thereby driving the two reset guide rods 605 to slide in the corresponding limit sliding groove 602 and squeeze the corresponding serpentine spring 604, so that the circuit board body 1 can always maintain a relatively tensioned state; when the device is reset from the bent state, since the active end of the circuit board body 1 slowly loses the traction tension, at this time, under the action of the rebound force of the two serpentine springs 604, the first limit rotating shaft 609 and the second limit rotating shaft 610 will push the circuit board body 1 in the opposite direction to move and fold and shrink, so that the circuit board body 1 can always maintain a relatively stable tensioned state without the excess bulge.

[0052] Furthermore, in this embodiment, the two second mounting holes 603 are both threadedly connected with second fixing screws 607 for limiting the movement of the reset guide rod 605. By providing the second fixing screws 607, an auxiliary limiting effect can be provided on the movement of the reset guide rod 605, and the reset guide rod 605 can also be prevented from detaching from the positioning bracket 401.

[0053] The working principle of this embodiment is as follows: both ends of the circuit board body 1 are fixedly connected with a plug-in reinforcement component 3. When in use, the plug-in reinforcement component 3 can be plugged into the wiring port of the application device, and then a fast and stable device connection can be achieved;

[0054] A stretching positioning component 4, a moving limiting component 5 and an elastic reset mechanism 6 are installed in the middle of the circuit board body 1. The circuit board body 1 is wound around the stretching positioning component 4 and the elastic reset mechanism 6 in an S shape, and the circuit board body 1 can be bent into an S shape in cooperation with the elastic reset mechanism 6;

[0055] When the folding portion of the application device begins to bend, one end of the circuit board body 1 will be stretched synchronously with the active end of the device, so that the active circuit board body 1 will further drive the first limit rotation shaft 609 and the second limit rotation shaft 610 to move in the direction of the stretching positioning component 4, thereby driving the two reset guide rods 605 to slide in the corresponding limit sliding grooves 602 and squeeze the corresponding serpentine springs 604, so that the circuit board body 1 can always maintain a relatively tensioned state;

[0056] When the device is reset from the bent state, the movable end of the circuit board body 1 slowly loses the traction force. At this time, under the action of the rebound force of the two serpentine springs 604, the first limit shaft 609 and the second limit shaft 610 will push the circuit board body 1 in the opposite direction to move and fold and shrink, so that the circuit board body 1 can always maintain a relatively stable tension state without any excess bulge.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A double-layer flexible circuit board, comprising a circuit board body (1), characterized in that: The front and rear ends of the top and bottom of the circuit board body (1) are both provided with elastic steel sheets (2), and both ends of the circuit board body (1) are fixedly connected with plug-in reinforcement components (3); A stretching and positioning component (4) is installed in the middle of the circuit board body (1), and the circuit board body (1) is wound around the stretching and positioning component (4) in an S shape; The top and bottom of the stretching positioning assembly (4) are both fixedly mounted with a movable limiting assembly (5) for limiting the folding portion of the circuit board body (1); An elastic reset mechanism (6) is slidably mounted on one side of the stretching positioning assembly (4) and is used for automatically resetting the circuit board body (1) after being stretched.

2. The double-layer flexible circuit board according to claim 1, characterized in that: The circuit board body (1) comprises a substrate layer (101), the top and bottom of the substrate layer (101) are provided with a plurality of evenly distributed copper wires (102), and the outer sides of the upper and lower groups of the copper wires (102) are both attached with insulating films (103).

3. The double-layer flexible circuit board according to claim 2, characterized in that: The plurality of elastic steel sheets (2) are respectively attached to the front and rear ends of the top and bottom of the base material layer (101).

4. The double-layer flexible circuit board according to claim 1, characterized in that: The plug-in reinforcement component (3) comprises a reinforcement plate (301) fixed to the end of the circuit board body (1); the top and bottom of the reinforcement plate (301) are provided with a plurality of evenly distributed copper plug-in pins (302); each of the copper plug-in pins (302) is electrically connected to the circuit board body (1) via a welding portion (303).

5. The double-layer flexible circuit board according to claim 1, characterized in that: The stretching positioning assembly (4) comprises two positioning brackets (401) installed at the front and rear ends of the circuit board body (1), and the two sides between the two positioning brackets (401) are respectively rotatably connected with a first positioning shaft (402) and a second positioning shaft (403), and the circuit board body (1) is S-shaped and passes through the two groups of first positioning shafts (402) and second positioning shafts (403), and two first mounting holes (405) are provided on the top and bottom of the outer sides of the two positioning brackets (401).

6. The double-layer flexible circuit board according to claim 5, characterized in that: A first through hole (404) is provided in the middle of each of the two positioning brackets (401).

7. The double-layer flexible circuit board according to claim 5, characterized in that: The movable limiting assembly (5) comprises two limiting rods (501) which are longitudinally distributed in parallel, a limiting plate (502) being fixedly connected between the two limiting rods (501), a second through hole (503) being provided in the middle of the limiting plate (502), front and rear ends of the two limiting rods (501) being fixedly connected with mounting seats (504), and a plurality of mounting seats (504) being fixed to corresponding first mounting holes (405) by first fixing screws (505).

8. The double-layer flexible circuit board according to claim 7, characterized in that: A plurality of fixing seats (506) are also fixedly connected to a group of movable limiting components (5) located at the bottom.

9. The double-layer flexible circuit board according to claim 5, characterized in that: The elastic reset mechanism (6) comprises a reset rail (601) fixed to one side of the two positioning brackets (401), the two reset rails (601) are provided with a limit slide groove (602), the two reset rails (601) are provided with a second mounting hole (603) on one side away from the positioning bracket (401), the two limit slide grooves (602) are provided with a serpentine spring (604), and the two limit slide grooves (602) are provided with a reset guide rod (605) slidably mounted therein. A limiting hole (606) is provided in the middle of the two reset guide rods (605); one end of the two reset guide rods (605) away from the positioning bracket (401) is fixedly connected to a rotating seat (608); a first limiting rotating shaft (609) and a second limiting rotating shaft (610) are rotatably connected between the two rotating seats (608); the circuit board body (1) passes through the first limiting rotating shaft (609) and the second limiting rotating shaft (610), and bypasses the second limiting rotating shaft (610).

10. The double-layer flexible circuit board according to claim 9, characterized in that: The two second mounting holes (603) are both threadedly connected with second fixing screws (607) for limiting the movement of the reset guide rod (605).

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