Dustproof sound transmission film for FPC and application of dustproof sound transmission film

Abstract

The invention relates to the technical field of dustproof sound-transmitting films for FPC (Flexible Printed Circuit), and provides a dustproof sound-transmitting film for FPC and application thereof, the manufacturing cost is reduced, two Mylar films need to be attached in the previous process, namely, a process dustproof Mylar film and a shipment dustproof Mylar film, the manufacturing cost is relatively high, only one dustproof sound-transmitting film needs to be attached in the existing process, and the dustproof sound-transmitting film can be made into a universal material, so that the manufacturing cost is relatively high. And the manufacturing cost is further reduced. The film specifically comprises a PI original film layer, a strong and weak double-faced adhesive tape layer and a dustproof sound transmission layer, the PI original film layer is used as a handle for stripping the dustproof sound transmission film before the whole machine is assembled; the strong and weak double-faced adhesive tape layer is used for bonding the dustproof sound transmission layer and the FPC back steel sheet; and the dustproof sound transmission layer can be smoothly stripped from the steel sheet before assembly.

Description

Technical Field

[0001] The present invention relates to the technical field of dustproof and sound-transmitting films for FPC, and in particular to a dustproof and sound-transmitting film for FPC and applications thereof. Background Art

[0002] MEMS microphones are microphones made based on MEMS technology. MEMS microphones are connected to the external environment through the sound inlet. The film (vibrating electrode plate) and the bottom plate (fixed electrode plate) are placed in the tiny gap between the sound hole and the back sound chamber (cavity) of the MEMS chip. The film and the bottom plate play the role of parallel plate capacitors. When the film vibrates due to sound pressure, the gap length between it and the bottom plate also changes, causing the electrostatic capacitance to change. MEMS microphones take out this change as an electrical signal, and are called electrostatic capacitance type microphones.

[0003] At present, MEMS microphones are basically mounted on the surface of FPC (flexible circuit board) through SMT technology. Since the sound inlet of MEMS microphone is open, dust and foreign matter can easily enter the MIC through the sound inlet during SMT and the subsequent manufacturing and transportation process of FPC, causing the film to rupture or foreign matter to form on the surface, resulting in MIC malfunction. Therefore, MIC needs to be dustproof after SMT and before the whole machine is assembled to prevent foreign matter from falling into it. Generally, the process is to attach the dustproof Mylar film 1 (with cross exhaust holes) to the FPC before SMT, attach the Mylar film 1 to perform SMT and the subsequent production of FPC, and then tear off the Mylar film 1 for testing during the acoustic test (MIC functional test), and then immediately attach the dustproof Mylar film 2 for shipment until it is completely torn off when the whole machine is assembled.

[0004] This process design effectively prevents dust and foreign matter from entering the MIC sound cavity and causing functional failure during the FPC manufacturing process, and improves product quality and yield. However, this process also has the following disadvantages: 1. Since the Mylar film needs to be laminated twice (process dustproof Mylar film 1 and shipping dustproof Mylar film 2) and the process dustproof Mylar film 1 needs to be torn off, the manufacturing cost is high and the production efficiency is low; 2. The product is easily wrinkled, torn, and broken during the film tearing process; 3. There is a risk of dust and foreign matter entering the MIC through the sound inlet hole without Mylar film protection during the MIC function test. Therefore, a new MIC dustproof process method is needed to solve the above problems. Summary of the invention

[0005] One of the purposes of the present invention is to provide a method for assembling a dustproof and sound-transmitting membrane for FPC to solve the above-mentioned problem.

[0006] The technical solution of the present invention is as follows:

[0007] A dustproof and sound-transmitting film for FPC, comprising a PI original film layer, a strong and weak double-sided adhesive layer and a dustproof and sound-transmitting layer;

[0008] The original PI film layer is used as a handle to peel off the dust-proof and sound-transmitting film before assembling the whole machine;

[0009] The strong and weak double-sided adhesive layer is used to bond the dustproof and sound-transmitting layer and the FPC back steel sheet;

[0010] The dustproof and sound-transmitting layer can be easily peeled off from the steel sheet before assembly.

[0011] Furthermore, the PI original film layer is made of polyimide material and has a thickness of 0.04 mm;

[0012] The strong and weak double-sided adhesive layer is made of PCT material with a thickness of 0.065mm;

[0013] The dustproof and sound-transmitting layer is made of PTFE material and has a thickness of 0.01 mm.

[0014] Another object of the present invention is to provide a method for preparing a product with FPC, the specific steps are as follows:

[0015] S100: Prepare a single FPC sheet in advance and prepare it for SMT through the following processes;

[0016] S200: Laminating the dustproof and sound-transmitting membrane as claimed in any one of claims 1 to 2 to the surface of the reinforcing steel sheet;

[0017] S300: SMT processing of products;

[0018] S400: Punch the entire FPC into shape to make the FPC into a single product;

[0019] S500: Perform acoustic testing on products;

[0020] S600: Appearance inspection, packaging and shipment;

[0021] S700: Tear off the dustproof and sound-transmitting film and inspect the product to ensure that the dustproof and sound-transmitting film has not fallen off;

[0022] S800: Assembled with the whole machine;

[0023] S900: proceed to the next assembly process.

[0024] Furthermore, step S200 is specifically as follows:

[0025] S210: Put the whole product into the laminating tooling;

[0026] S220: Put the tooling containing the product on the platform of the automatic laminating tape machine, and stop it in place according to the set transport track feed plate stop. At the same time, the rolled dustproof and sound-transmitting film is fed to the optical fiber sensor according to the set feeder and stops on the receiving platform;

[0027] S230: The XYZR axis of the automatic adhesive tape machine drives the suction head to the top of the material to suck up the dust-proof and sound-transmitting film, and confirms the success of suction based on the vacuum negative pressure value of the suction head;

[0028] S240: The suction head moves past the CCD camera to take a picture, and then the material position is calculated by the visual algorithm.

[0029] The upper CCD camera takes pictures at the board mounting position and calculates the mounting position through the visual algorithm;

[0030] S250: The automatic tape laminating machine combines the visual calculation results of the upper CCD camera and the lower CCD camera to automatically adjust the XYZR axis of the equipment to move the placement head to the top of the laminating position;

[0031] S260: The suction head of the placement head controls the vacuum negative pressure suction nozzle to press down to the bonding position of the board according to the setting, completing one bonding;

[0032] S270: The automatic adhesive tape machine repeats steps S230 to S260 until all points are mounted;

[0033] S280: The track stop is released, the board flows out through the track, and the next CT starts.

[0034] Furthermore, the laminating tooling in step S210 includes a cover plate and a base, and the product is located between the cover plate and the base;

[0035] The base is provided with positioning posts corresponding to the positioning holes on the FPC. When the product is placed on the base, the positioning posts are put on and then the cover is replaced;

[0036] A hinge structure is arranged between the cover plate and the base.

[0037] Furthermore, the automatic adhesive tape laminating machine in step S220 includes a frame, an X-axis operating unit, a Y-axis operating unit, a double-track assembly line unit, a tray loading and unloading unit, and a bottom image acquisition unit disposed on the frame;

[0038] The placement components and suction heads used for sucking and placing auxiliary materials are installed on the X-axis operation unit;

[0039] The Y-axis operation unit includes a fixture assembly for clamping a fixture loaded with auxiliary materials to be mounted;

[0040] The dual-track assembly line unit includes an assembly line track assembly for conveying the bonding tooling;

[0041] The pallet loading and unloading unit includes a pallet lifting component that moves the auxiliary material pallet to the mounting component picking position, through the coordination of the frame, dual X-axis operation unit, Y-axis operation unit, dual-track assembly line unit, pallet loading and unloading unit and bottom image acquisition unit.

[0042] Furthermore, step S300 includes:

[0043] S310: Mount the product on the FPC surface pad;

[0044] S320: Apply glue around the MIC. The glue should completely cover the device body and not cover the MIC.

[0045] S330: Perform SMT;

[0046] S340: Perform 100% X-Ray scanning to check whether the MIC has a broken ring.

[0047] Furthermore, the reinforcing steel sheet is pressed onto the back of the FPC through a thermosetting adhesive film, and the tolerance of the bonding position with the FPC is controlled within ±0.1 mm.

[0048] The working principle and beneficial effects of the present invention are:

[0049] 1. The present invention reduces the manufacturing cost. The previous process required laminating two Mylar films, namely, the process dustproof Mylar film and the shipping dustproof Mylar film, which had a high manufacturing cost. The current process only requires laminating one dustproof and sound-transmitting film, and the dustproof and sound-transmitting film can be made into a universal material, further reducing the manufacturing cost.

[0050] 2. Improve production efficiency. Compared with the previous process, reduce the one-time Mylar film laminating process and film tearing process;

[0051] 3. Improve product quality and reduce the adverse effects such as wrinkles, product damage and breakage caused by film tearing.

[0052] 4. The risk of dust and foreign matter entering the MIC is further reduced. Compared with the previous process, the dust-proof Mylar film can be used for acoustic testing with the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0054] Figure 1 It is the top view of the product;

[0055] Figure 2 This is the bottom view of the product;

[0056] Figure 3 It is a schematic diagram of the FPC structure;

[0057] Figure 4 This is a schematic diagram of the reinforcement steel sheet structure;

[0058] Figure 5 This is a schematic diagram of the dust-proof and sound-transmitting layer;

[0059] Figure 6 This is a schematic diagram of the structure of the dustproof sound-transmitting membrane and PFC assembly;

[0060] Figure 7 This is the schematic diagram of the product after SMT assembly;

[0061] Figure 8 It is a structural diagram of the positioning column of the fitting;

[0062] Fig. 9 It is a schematic diagram of the structure of the positioning hole of the fitting;

[0063] Fig.10 This is a schematic diagram of the structure of an automatic adhesive tape laminating machine;

[0064] Fig.11 This is a cross-sectional view of the product;

[0065] Fig.12 This is the side view of the reinforcement steel plate;

[0066] Fig.13 This is the side view of the dustproof and sound-transmitting membrane;

[0067] Fig.14 This is a schematic diagram of the dust-proof and sound-transmitting membrane;

[0068] Fig.15 This is the schematic diagram of the assembly before SMT.

[0069] In the figure: 1, MEMS microphone; 11, MIC sound inlet; 12, MIC pad; 13, film and bottom plate; 14, MIC wall;

[0070] 2. FPC; 21. FPC sound inlet hole; 22. FPC solder pad;

[0071] 3. Reinforcement steel sheet; 31. Steel sheet sound hole; 32. Thermosetting adhesive film;

[0072] 4. Dustproof and sound-transmitting layer; 41. Strong and weak double-sided adhesive tape; 42. PI original film;

[0073] 71. Glue;

[0074] 81. Positioning column; 82. Positioning hole; 83. Hinge; 84. Cover plate; 85. Base. DETAILED DESCRIPTION

[0075] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0076] Embodiment 1

[0077] like Figure 5 , 13 -14, a dustproof and sound-transmitting film for FPC2, including but not limited to being used in electronic products like microphones or with microphones. Its structure mainly includes PI original film 42 layers, strong and weak double-sided adhesive 41 layers and dustproof and sound-transmitting layer 4.

[0078] Specifically, the 42 layers of the PI original film are used as a handle for peeling off the dustproof and sound-transmitting film before the whole machine is assembled. It is made of polyimide material, with a thickness of 0.04mm and high temperature resistance of 260℃.

[0079] The 41 layers of strong and weak double-sided adhesive are made of PCT material with a thickness of 0.065mm; the preferred model is: HSY260-100PI, which can withstand a high temperature of 260°C, has a tensile strength of Min 115N / 25mm, and an elongation at break of Min 50%. The peeling force required for contact with the steel sheet is 500gf, and the peeling force required for contact with the dustproof and sound-transmitting film is 800gf. It is used to bond the dustproof and sound-transmitting layer 4 and the steel sheet on the back of FPC2.

[0080] The dustproof and sound-transmitting layer 4 is made of PTFE material with a thickness of 0.01mm, so that the dustproof and sound-transmitting membrane can be easily peeled off from the steel sheet before assembly. Material model: Sound source SYF-A001SG, with a maximum temperature resistance of 260℃ / 15min and an air permeability of 13000. It is suitable for balancing the pressure difference inside and outside the MIC cavity during MIC reflow soldering, and plays a role in dustproof and waterproof.

[0081] The specific anti-static parameters of the overall dust-proof and sound-transmitting membrane are: a. 105-109Ω b. Voltage <100V; the outer dimensions of the dust-proof and sound-transmitting membrane are 0.2mm inward on one side of the steel sheet, and cannot exceed the steel sheet after bonding.

[0082] This embodiment designs a new dustproof and sound-permeable membrane, which is a selectively permeable film that allows certain substances to pass through and prevents other substances from passing through. This property depends on the pore size of the membrane. Specifically, the distance between gas molecules is large, and they can pass through the air holes of the dustproof and sound-permeable membrane during the diffusion movement, while the volume of dust and debris is large and cannot pass through the dustproof and sound-permeable membrane, and the distance between liquid molecules is smaller than the distance between the air holes, and under the action of surface tension, liquid molecules cannot pass through the dustproof and waterproof sound-permeable membrane, thereby playing a role in dustproof and waterproof. The pore size range of this membrane is usually between 0.1-10μm, and its main functions include waterproofing, dustproofing, breathability, heat dissipation, and balancing internal and external air pressure. The material of the dustproof and sound-permeable layer 4 can be PTFE, Nylon, PES, PVDF, PP, NC, MCE, PETE and other microporous membranes, among which the dustproof and sound-permeable layer 4 made of PTFE is widely used in the field of dustproof, waterproof and breathable due to its good chemical stability and natural hydrophobicity.

[0083] Embodiment 2

[0084] like Figure 1-15 As shown, a method for preparing a product with FPC 2 is mainly applicable to the production of MEMS microphone 1 or electronic products of the same type, and the specific steps are as follows:

[0085] S100: Prepare a single FPC2 as a whole panel in advance, and prepare it for SMT through processes such as cutting, drilling, copper plating, circuit forming, laminating cover film, gold plating, high voltage testing, and pressing reinforcing steel sheet 3;

[0086] The same sound inlet holes are preset at the positions of FPC2 and the back reinforcing steel sheet 3 (attached to the back of FPC2 to support the MIC) corresponding to the MIC sound inlet hole 11. The sizes of the sound inlet holes are designed as follows: the diameter of the MIC sound inlet hole 11 is 0.325mm, the diameter of the FPC sound inlet hole 21 is 0.7mm, and they are made by drilling without producing drilling burrs. The diameter of the sound inlet hole of the reinforcing steel sheet 3 is 1.0mm, and it can be made by punching and cutting technology to ensure that the wall of the sound inlet hole is smooth.

[0087] The reinforcing steel sheet 3 is pressed onto the back of FPC2 through the thermosetting adhesive film 32, and the tolerance of the bonding position with FPC2 is controlled within ±0.1mm. It is preferably laminated using an automatic steel sheet machine to ensure accuracy. When pressing the reinforcing steel sheet 3, the surface of the FPC pad 22 must be flat, and the overflow of the thermosetting adhesive film 32 is required to be controlled within <0.05mm.

[0088] S200: attaching the dustproof and sound-transmitting membrane in the first embodiment to the surface of the reinforcing steel sheet 3;

[0089] The dustproof and sound-transmitting film can be made into a roll-loaded tape material, using an automatic suction lamination process, with a lamination tolerance of ≤0.15mm. The appearance of the dustproof and sound-transmitting film is 0.2mm more than the steel sheet reinforcement on one side, and the dustproof and sound-transmitting film can be laminated using an automatic adhesive tape laminating machine;

[0090] Before SMT, a dustproof and sound-transmitting membrane is attached to the MIC reinforcing steel sheet 3 at the back of FPC2 to cover the sound inlet hole, thereby achieving the effect of dustproof and waterproof.

[0091] Step S200 is specifically as follows:

[0092] S210: Put the whole product into the laminating tooling;

[0093] The laminating tooling in step S210 includes a cover plate 84 and a base 85. The product is located between the cover plate 84 and the base 85. The product is placed in the middle position. The base 85 plays a supporting role and is generally made of a pad with a thickness of about 6 mm.

[0094] The base 85 is provided with positioning posts 81 corresponding to the positioning holes 82 on the FPC2. The size of the positioning posts 81 is φ2.0mm. At least 6 groups are provided. The size and position are the same as those of the positioning holes 82 of the FPC2. The product is placed on the base 85, the positioning posts 81 are put on, and then the cover plate 84 is put on. The cover plate 84 plays a fixing role and is made of SUS stainless steel with a thickness of 0.2mm. When the product is placed on the base 85, the positioning posts 81 are put on, and then the cover plate 84 is replaced;

[0095] A hinge 83 structure is provided between the cover 84 and the base 85, which can be opened and closed by means of the hinge 83. The cover 84 needs to avoid the position of the dustproof and sound-transmitting membrane to facilitate identification and fitting. The cover 84 has a single-sided avoidance of min. 0.5mm compared to the foam.

[0096] S220: Put the tooling containing the product on the platform of the automatic laminating tape machine, and stop it in place according to the set transport track feed plate stop. At the same time, the rolled dustproof and sound-transmitting film is fed to the optical fiber sensor according to the set feeder and stops on the receiving platform;

[0097] The automatic adhesive tape laminating machine in step S220 includes a frame, an X-axis operating unit, a Y-axis operating unit, a double-track assembly line unit, a tray loading and unloading unit, and a bottom image acquisition unit.

[0098] The placement components and suction heads used for sucking and placing auxiliary materials are installed on the X-axis operation unit;

[0099] The Y-axis operation unit includes a fixture assembly for clamping a fixture loaded with auxiliary materials to be mounted;

[0100] The dual-track assembly line unit includes an assembly line track assembly for conveying the bonding tooling;

[0101] The pallet loading and unloading unit includes a pallet lifting component that moves the auxiliary material pallet to the mounting component picking position, through the coordination of the frame, dual X-axis operation unit, Y-axis operation unit, dual-track assembly line unit, pallet loading and unloading unit and bottom image acquisition unit.

[0102] S230: The XYZR axis of the automatic adhesive tape machine drives the suction head to the top of the material to suck up the dust-proof and sound-transmitting film, and confirms the success of suction based on the vacuum negative pressure value of the suction head;

[0103] S240: The suction head moves past the CCD camera to take a picture, and then the material position is calculated by the visual algorithm.

[0104] The upper CCD camera takes pictures at the board mounting position and calculates the mounting position through the visual algorithm;

[0105] S250: The automatic tape laminating machine combines the visual calculation results of the upper CCD camera and the lower CCD camera to automatically adjust the XYZR axis of the equipment to move the placement head to the top of the laminating position;

[0106] S260: The suction head of the placement head controls the vacuum negative pressure suction nozzle to press down to the bonding position of the board according to the setting, completing one bonding;

[0107] S270: The automatic adhesive tape machine repeats steps S230 to S260 until all points are mounted;

[0108] The best efficiency of the equipment: 0.6s / psc. Both the X-axis and Y-axis are suitable for linear motors, the X-axis speed can reach 2.5m / s, the acceleration is 2.5g, the Y-axis speed can reach 2m / s, the acceleration is 2g, the grating scale encoder has a resolution of 1um.

[0109] S280: The track stop is released, the board flows out through the track, and the next CT starts.

[0110] The automatic adhesive tape laminating machine in this embodiment includes: a frame, two X-axis operating units arranged on the frame, a Y-axis operating unit, a double-track assembly line unit, a tray loading and unloading unit, and a bottom image acquisition unit;

[0111] The X-axis operation unit includes a placement component and a suction nozzle for sucking and placing auxiliary materials;

[0112] The Y-axis operation unit includes a fixture assembly for clamping a fixture loaded with auxiliary materials to be mounted;

[0113] The double-track assembly line unit includes an assembly line track component for transmitting the bonding tooling; the pallet loading and unloading unit includes a pallet lifting component for moving the auxiliary material pallet to the mounting component picking position. Through the coordination of the frame, double X-axis operation unit, Y-axis operation unit, double-track assembly line unit, pallet loading and unloading unit and bottom image acquisition unit, the auxiliary materials are fed in the form of pallets and the products are loaded with bonding tooling for automated production. The fully automatic online bonding machine replaces manual operation, improves bonding efficiency, saves manpower and material resources, and the bonding accuracy is controlled to ≤0.15mm.

[0114] S300: SMT processing of products;

[0115] Step S300 includes:

[0116] S310: Mount the product on the solder pad on the surface of FPC2. The dustproof and sound-transmitting film must not fall off during the process.

[0117] S320: Glue is applied around the MIC. The glue 71 should completely cover the periphery of the device body and not cover the MIC.

[0118] S330: Perform SMT;

[0119] S340: Perform 100% X-Ray scanning to check whether the MIC has a broken ring.

[0120] Among them, the thickness of the steel mesh is 0.08mm, the opening rate: opening area / pad area: 80%~110%, the width-to-thickness ratio: >1.5, the area ratio: >0.7, the solder paste uses ALPHAOM-340 (No. 4 powder), and when it contains 01005 and MIC at the same time, use ALPHAOM-3405 powder solder paste, printing parameters: printing speed: 50mm / s±20mm / s, scraper pressure: 3Kg±1Kg, demolding speed: 0.3mm / s±0.2mm / s, glue 71 uses underfill type, preferably sub-poly black 0711H-HF, dispensing can make the MIC in a closed state all around, and the sound can only enter the MIC through FPC2 and the steel sheet reinforced sound inlet hole to prevent noise from entering, thereby improving the noise reduction and anti-interference performance of the MIC. After SMT, 100% X-Ray scanning should be performed to check whether the MIC has a broken ring (a broken ring is a defective product, which will cause a gap and cause sound leakage).

[0121] S400: Punch the entire FPC2 to make it a single product;

[0122] The tolerance of the punching shape is controlled within ±0.1mm. During the whole process, the dust-proof and sound-transmitting membrane must be prevented from falling off. When punching, it is forbidden to use an air gun to blow dust at the knife edge and directly blow near the MIC sound inlet hole 11. You can use a dust-free cloth to wipe it. When taking and placing the product, you must use anti-static tweezers and wear an anti-static wrist guard to avoid electrostatic damage to the MIC.

[0123] S500: Perform acoustic test on the product, the purpose is to test the welding performance of MIC and FPC2 and the acoustic function of MIC, and also test the airtightness of MIC dispensing. The audio test equipment (VDD: 2.7V) allows the standard sound source to emit a 1KHz sound source (94dB@1KHz); measure the 1Khz sensitivity of MIC, the general standard is -38±1dB, the measurable range: 200-10KHz, distortion (THD), the standard is <5%, during the test, the operator needs to wear anti-static clothing, and wear a mask, gloves or finger caps, and work in a dust-free environment, temperature / humidity requirements: room temperature 20-30℃, humidity 65%RH-75%RH. During the test, prevent the dustproof and sound-permeable membrane from falling off.

[0124] S600: Appearance inspection, packaging and shipment;

[0125] Check whether the product has any defects such as external damage. The dust-proof and sound-transmitting film must not be displaced or fall off during the process. 0.6mm anti-static blister boxes can be used for packaging. The blister boxes need to be cleaned on time during product turnover to avoid accumulation of debris and other foreign matter.

[0126] S700: Tear off the dustproof and sound-transmitting film and inspect the product to ensure that the dustproof and sound-transmitting film has not fallen off;

[0127] S800: Assembled with the whole machine;

[0128] S900: After peeling off the entire dustproof and sound-transmitting membrane through the PET tearing tool, proceed to the next assembly process.

[0129] The use process of the dustproof and sound-transmitting membrane in this embodiment is SMT pre-lamination, and the dustproof and sound-transmitting membrane is attached for SMT and post-production of FPC2 until it is completely torn off when the whole machine is assembled. During the FPC2 manufacturing process, dustproof measures are taken for the MIC sound inlet 11 throughout the entire process, which effectively prevents dust and foreign matter from entering the MIC sound cavity and causing functional failure, improves product quality and yield, reduces manufacturing costs, and improves production efficiency. At the same time, the MEMS microphone 1 is glued during SMT, which effectively prevents the MIC from generating noise and leakage and other defects, and improves the noise reduction level of the MIC. This method is easy to operate, has good dustproof effect, low production cost, high production efficiency, is easy to mass produce, and also improves the overall performance of the MIC.

[0130] The above are only preferred embodiments of the present invention and are 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 in the protection scope of the present invention.

Claims

1. A dustproof and sound-transmitting membrane for FPC (2), characterized in that: It comprises a PI original film (42) layer, a strong and weak double-sided adhesive (41) layer and a dustproof and sound-transmitting layer (4); The PI original film (42) layer is used as a handle for peeling off the dustproof and sound-transmitting film before assembling the whole machine; The strong and weak double-sided adhesive (41) layer is used to bond the dustproof and sound-transmitting layer (4) and the steel sheet on the back of the FPC (2); The dustproof and sound-transmitting layer (4) can be easily peeled off from the steel sheet before assembly.

2. A dustproof and sound-transmitting membrane for FPC (2) as claimed in claim 1, characterized in that: The PI original film (42) layer is made of polyimide material and has a thickness of 0.04 mm; The strong and weak double-sided adhesive (41) layer is made of PCT material and has a thickness of 0.065 mm; The dustproof and sound-transmitting layer (4) is made of PTFE material and has a thickness of 0.01 mm.

3. A method for preparing a product with FPC (2), characterized in that: The specific steps are as follows: S100: pre-assemble a single FPC (2) into a whole sheet and prepare it for SMT through the process; S200: Laminating the dustproof and sound-transmitting membrane as described in any one of claims 1 to 2 to the surface of the reinforcing steel sheet (3); S300: SMT processing of products; S400: Punching the entire FPC (2) into a shape so that the FPC (2) becomes a single product; S5 00: Perform acoustic testing on the product; S600: Appearance inspection, packaging and shipment; S700: Tear off the dustproof and sound-transmitting film and inspect the product to ensure that the dustproof and sound-transmitting film has not fallen off; S800: Assembled with the whole machine; S900: proceed to the next assembly process.

4. A method for preparing a product with FPC (2), characterized in that: Step S200 is specifically as follows: S210: Put the whole product into the laminating tooling; S220: Put the tooling containing the product on the platform of the automatic laminating tape machine, and stop it in place according to the set transport track feed plate stop. At the same time, the rolled dustproof and sound-transmitting film is fed to the optical fiber sensor according to the set feeder and stops on the receiving platform; S230: The XYZR axis of the automatic adhesive tape machine drives the suction head to the top of the material to suck up the dust-proof and sound-transmitting film, and confirms the success of suction based on the vacuum negative pressure value of the suction head; S240: The suction head moves past the CCD camera to take a picture, and then the material position is calculated by the visual algorithm. The upper CCD camera takes pictures at the board mounting position and calculates the mounting position through the visual algorithm; S250: The automatic tape laminating machine combines the visual calculation results of the upper CCD camera and the lower CCD camera to automatically adjust the XYZR axis of the equipment to move the placement head to the top of the laminating position; S260: The suction head of the placement head controls the vacuum negative pressure suction nozzle to press down to the bonding position of the board according to the setting, completing one bonding; S270: The automatic adhesive tape machine repeats steps S230 to S260 until all points are mounted; S280: The track stop is released, the board flows out through the track, and the next CT starts.

5. A method for preparing a product with FPC (2) according to claim 4, characterized in that: The laminating tool in step S210 includes a cover plate (84) and a base (85), and the product is located between the cover plate (84) and the base (85); The base (85) is provided with a positioning column (81) for corresponding to the positioning hole (82) on the FPC (2). When the product is placed on the base (85), the positioning column (81) is put on, and then the cover plate (84) is replaced; A hinge (83) structure is provided between the cover plate (84) and the base (85).

6. A method for preparing a product with FPC (2) according to claim 5, characterized in that: The automatic adhesive tape laminating machine in step S220 includes a frame, an X-axis operating unit, a Y-axis operating unit, a double-track assembly line unit, a tray loading and unloading unit, and a bottom image acquisition unit. The placement components and suction heads used for sucking and placing auxiliary materials are installed on the X-axis operation unit; The Y-axis operation unit includes a fixture assembly for clamping a fixture loaded with auxiliary materials to be mounted; The dual-track assembly line unit includes an assembly line track assembly for conveying the bonding tooling; The pallet loading and unloading unit includes a pallet lifting component that moves the auxiliary material pallet to the mounting component picking position, through the coordination of the frame, dual X-axis operation unit, Y-axis operation unit, dual-track assembly line unit, pallet loading and unloading unit and bottom image acquisition unit.

7. A method for preparing a product with FPC (2) according to claim 6, characterized in that: Step S300 includes: S310: Mount the product on the surface pad of FPC (2); S320: Apply glue around the MIC, and the glue (71) should completely cover the periphery of the device body and not cover the MIC; S330: Perform SMT; S340: Perform 100% X-Ray scanning to check whether the MIC has a broken ring.

8. A method for preparing a product with FPC (2) according to claim 7, characterized in that: The reinforcing steel sheet (3) is pressed onto the back of the FPC (2) via a thermosetting adhesive film (32), and the tolerance of the bonding position with the FPC (2) is controlled within ±0.1 mm.

Images