A puncture-proof protection structure of a vehicle-mounted backlight FPC

Abstract

The application discloses a kind of anti-puncture protection structures of vehicle-mounted backlight FPC, it is related to the field of vehicle-mounted display backlight module, the anti-puncture protection structure is set to FPC body surface, FPC body is divided into circuit concentration area and component contact area corresponding vehicle-mounted backlight assembly working condition, anti-puncture protection structure is used to carry out zoned protection to FPC body vulnerable area of puncture, anti-puncture protection structure includes flexible silica gel protection pad layer and transparent anti-puncture film, wherein flexible silica gel protection pad layer is fixedly attached to the surface of circuit concentration area, its contour is matched with circuit concentration area, and edge reserved avoidance gap;Transparent anti-puncture film is fixedly attached to the surface of component contact area, and transparent anti-puncture film is made of polyimide material;This kind of anti-puncture protection structure of vehicle-mounted backlight FPC, through zoned differential protection, consider anti-puncture, flexible and light-transmitting performance.

Description

Technical Field

[0001] This invention relates to automotive display backlight module technology, specifically to a puncture-resistant protection structure for automotive backlight FPC. Background Technology

[0002] With the rapid development of automotive intelligence and connectivity, in-vehicle display systems, as the core interface for human-vehicle interaction, are experiencing continuous expansion in application scenarios and functional requirements. The installation rate of display devices such as in-vehicle central control screens, instrument panels, passenger entertainment screens, and rear-seat entertainment screens is increasing year by year, and the market is placing increasingly stringent requirements on the performance, reliability, safety, and lifespan of in-vehicle display products.

[0003] Flexible printed circuit boards (FPCs), as key interconnect components in automotive backlight modules, are responsible for the electrical signal transmission and power supply of LED chips. During the actual assembly and operation of automotive backlight modules, FPCs are typically positioned between the light guide plate and the backlight module structural components, with their surfaces in close contact or adherence to the edges of the light guide plate, metal structural components, and mounting clips. Due to the unique characteristics of automotive applications, FPCs face the following prominent challenges in practical use:

[0004] Risk of puncture in light guide plate. Light guide plates in automotive backlight modules are typically made of high-hardness optical plastics such as PMMA or PC, with injection molding burrs or sharp edges from cutting. During module assembly and pressing, machine vibration, or thermal expansion and contraction, the edges of the light guide plate continuously press against the FPC surface. The densely packed circuit areas of the FPC contain fine conductive lines with a spacing of only 0.1–0.2 mm. These areas have thin substrates and weak puncture resistance, making them highly susceptible to puncture by the burrs or edges of the light guide plate. This can lead to open circuits or short circuits, resulting in backlight malfunction, display abnormalities, and even safety hazards due to overheating caused by short circuits.

[0005] Risks of component contact friction and foreign object puncture. There are contact surfaces between the FPC and the metal structural components and mounting clips of the automotive backlight module. Under conditions of continuous vibration (10-2000Hz) generated by vehicle movement and repeated expansion and contraction of materials due to high and low temperature cycling (-40℃ to 85℃), the surface of the FPC contact area constantly experiences relative friction and fretting wear with the contacting components. Simultaneously, small, sharp foreign objects such as metal shavings and debris that may remain inside the module can embed or pierce the FPC surface under vibration, causing insulation damage and circuit damage.

[0006] To address the aforementioned issue of FPCs being easily punctured, the inventors, after searching the existing technology, have identified the following technical solutions:

[0007] 1) Chinese Patent Publication No. CN222071007U discloses a backlight module for preventing burrs from piercing an FPC. In this patent application, a lower iron frame, a reflective sheet, a light guide plate, and an optical film assembly are stacked sequentially from bottom to top. The lower iron frame includes a base plate and sidewalls extending upward from the edge of the base plate. There are four sidewalls that form a frame. An FPC is fixed on one of the sidewalls. Thermally conductive adhesive is disposed between the FPC and the sidewall. Multiple LEDs are fixed on the FPC. The LEDs are aligned with the light-incident surface of the light guide plate. One end of the FPC extends and bends to another sidewall. A scratch-resistant PI layer is fixed at the bend of the FPC. The scratch-resistant PI layer is disposed between the FPC and the thermally conductive adhesive. Because the FPC has a scratch-resistant PI layer fixed at the bend, PI is an organic polymer material with anti-corrosion, anti-fatigue and anti-wear properties. Even if the burrs of the lower iron frame puncture the thermally conductive adhesive, the scratch-resistant PI layer can protect the FPC and the circuitry inside the FPC, effectively preventing the burrs from puncturing the FPC.

[0008] 2) Chinese Patent Publication No. CN119987082A discloses an optimized structure for a liquid crystal display module FPC to prevent circuit breakage. This patent application includes: a module FPC with AK pad windows on its back side. The AK pads are used for soldering to a backlight FPC. The AK pad window area has a top boundary, a bottom boundary, a left boundary, and a right boundary, forming an irregular shape. Empty PIN circuit patterns for connecting to ground terminals are respectively provided on the left and right edges of the AK pads. A reinforcing PI cover film for structural reinforcement is also provided on the front side of the module FPC. This optimized structure for a liquid crystal display module FPC to prevent circuit breakage, through the irregular AK pad window area, empty PIN circuit patterns, and reinforcing PI cover film, comprehensively increases the strength of the pad window location. Under bending stress, it can effectively improve stress concentration, reduce the risk of circuit breakage, and ensure product quality.

[0009] In the aforementioned existing technical solutions, local protection is provided to the FPC by setting an anti-scratch PI layer or adding a reinforcing PI cover film at the bending point, which improves the puncture resistance or fracture resistance of specific areas of the FPC to a certain extent. However, the above solutions only set up protective structures for a single specific area of ​​the FPC (bending area or pad opening area), without considering the fundamental difference in the types and sources of puncture risks faced by the dense wiring area and the component contact area under actual automotive backlight assembly conditions. That is, the dense wiring area mainly suffers from the extrusion puncture from the back light guide plate, while the component contact area mainly suffers from the friction and foreign object puncture from the front structural components. The two areas require different protection strategies and materials for targeted protection. However, the existing technology uses a single homogeneous protection method, which cannot achieve differentiated and precise protection for different areas on the same FPC, and it is difficult to take into account the comprehensive requirements of puncture resistance, bending flexibility, backlight transmittance and assembly adaptability. Summary of the Invention

[0010] The purpose of this invention is to provide a puncture-proof protection structure for vehicle-mounted backlight FPC, in order to solve the problems in the prior art that do not provide differentiated protection for different types of puncture risks faced by different functional areas of FPC, and that it is difficult to take into account puncture resistance, bending flexibility and backlight transmittance.

[0011] To achieve the above objectives, the present invention provides the following technical solution: a puncture-resistant protection structure for an automotive backlight FPC, wherein the puncture-resistant protection structure is disposed on the surface of the FPC body, the FPC body is divided into a dense wiring area and a component contact area corresponding to the automotive backlight assembly condition, and the puncture-resistant protection structure is used to provide zoned protection for the easily punctured weak areas of the FPC body, the puncture-resistant protection structure comprising:

[0012] A flexible silicone protective pad is attached to the surface of the densely wired area. The thickness of the flexible silicone protective pad is set to 0.05mm to 0.1mm. Its shape and contour match the densely wired area, and a clearance is reserved at the edge.

[0013] A transparent puncture-resistant film is laminated and fixed to the surface of the contact area of ​​the component. The transparent puncture-resistant film is made of polyimide material and the maximum thickness is set to 0.03mm.

[0014] The flexible silicone protective pad and the transparent puncture-resistant film form a zoned and differentiated protective structure, which provides targeted protection against the puncture risk of different areas of the FPC body. While retaining the bending flexibility and backlight transmission performance of the FPC body, it improves the overall puncture resistance, abrasion resistance and environmental resistance of the FPC.

[0015] Furthermore, the thickness of the flexible silicone protective pad is less than 1 / 2 of the spacing between FPC body lines in densely packed areas, wherein the spacing between FPC body lines is 0.1 to 0.2 mm.

[0016] Furthermore, the clearance reserved at the edge of the flexible silicone protective pad is 0.02mm, and the clearance is located between the flexible silicone protective pad and the pad area and interface area of ​​the FPC body.

[0017] Furthermore, the transparent puncture-resistant film has a light transmittance of ≥90% and a thickness of 0.01~0.03mm.

[0018] Furthermore, the flexible silicone protective pad is bonded and fixed to the FPC body through a high-temperature pressing process. The pressing temperature is 120℃±5℃, the pressing pressure is 0.3MPa, and the pressing time is 15s.

[0019] Furthermore, the transparent puncture-resistant film is bonded to the FPC body through a low-temperature lamination process and a rolling process, with a lamination temperature of 60℃±3℃.

[0020] Furthermore, the flexible silicone protective pad has a three-layer composite structure, including a bottom silicone gel buffer layer, a middle puncture-resistant skeleton layer, and a top abrasion-resistant protective layer, wherein:

[0021] The bottom silicone gel buffer layer is directly bonded to the surface of the FPC body;

[0022] The intermediate puncture-resistant skeleton layer is a PI film or metal foil;

[0023] The top wear-resistant protective layer is a polyurethane layer.

[0024] Furthermore, the metal foil is copper foil or aluminum foil, and its thickness is 0.01 to 0.03 mm.

[0025] Furthermore, a microencapsulated repair agent is uniformly incorporated into the flexible silicone protective pad and the transparent puncture-resistant film. The microencapsulated repair agent is configured such that when a micro-puncture wound occurs in the protective structure, the microcapsules rupture and release a repair medium. This repair medium can react with moisture in the air or a catalyst embedded in the substrate to automatically heal the micro-puncture wound.

[0026] Compared with existing technologies, the present invention provides a puncture-resistant protection structure for automotive backlight FPCs. On one hand, by dividing the FPC body into a dense wiring area and a component contact area corresponding to the automotive backlight assembly process, and by attaching a flexible silicone protective pad to the dense wiring area and a transparent puncture-resistant film to the component contact area, a differentiated protection structure is formed. This achieves targeted and precise protection against different types of puncture risks faced by different functional areas of the FPC, overcoming the limitations of existing technologies that only provide homogeneous protection for a single specific area. On the other hand, by setting the thickness of the flexible silicone protective pad to less than half the distance between adjacent wiring in the dense wiring area and controlling the light transmittance of the transparent puncture-resistant film to ≥90%, the bending flexibility and backlight transmittance of the FPC body are preserved while ensuring puncture resistance, thus balancing protective effect and core product performance. The differentiated protection structure of the present invention can adapt to high and low temperature environments and vibration conditions, and can withstand the puncture of a 0.05mm diameter sharp object under 5N pressure, significantly improving the overall reliability and service life of automotive backlight FPCs in harsh automotive environments. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0028] Figure 1 This is a schematic diagram showing the partitioning of the dense circuit area and component contact area of ​​the FPC body in Embodiment 1 of the present invention;

[0029] Figure 2 This is a schematic diagram showing the bonding position of the flexible silicone protective pad and the transparent puncture-resistant film on the surface of the FPC body in Embodiment 1 of the present invention.

[0030] Figure 3 This is a schematic cross-sectional view of the three-layer composite structure of the flexible silicone protective pad in Embodiment 2 of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. FPC body; 101. Dense circuit area; 102. Component contact area; 2. Flexible silicone protective pad layer; 201. Bottom silicone gel buffer layer; 202. Middle puncture-resistant skeleton layer; 203. Top abrasion-resistant protective layer; 3. Transparent puncture-resistant film. Detailed Implementation

[0033] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0034] As attached Figure 1 To be continued Figure 2 As shown:

[0035] Example 1:

[0036] This invention provides a puncture-resistant protection structure for an automotive backlight FPC. The puncture-resistant protection structure is disposed on the surface of the FPC body 1. The FPC body 1 is divided into a dense wiring area 101 and a component contact area 102 corresponding to the automotive backlight assembly condition. The puncture-resistant protection structure is used to provide zoned protection for the vulnerable areas of the FPC body 1 that are easily punctured. The puncture-resistant protection structure includes a flexible silicone protective pad 2 and a transparent puncture-resistant film 3. The flexible silicone protective pad 2 and the transparent puncture-resistant film 3 form a zoned differentiated protection structure, which provides targeted protection for the puncture risk of different areas of the FPC body 1. While retaining the bending flexibility and backlight transmittance of the FPC body 1, the overall puncture resistance, wear resistance and environmental resistance of the FPC are improved.

[0037] 1. In one embodiment of the present invention, the flexible silicone protective pad 2 is attached and fixed to the surface of the densely packed circuit area 101. The thickness of the flexible silicone protective pad 2 is set to 0.05mm, its outline matches the densely packed circuit area 101, and the edge is reserved with a clearance.

[0038] 2. In one embodiment of the present invention, a transparent puncture-resistant film 3 is compositely fixed to the surface of the component contact area 102. The transparent puncture-resistant film 3 is made of polyimide material and the maximum thickness is set to 0.03 mm.

[0039] 3. In one embodiment of the present invention, the thickness of the flexible silicone protective pad 2 is less than 1 / 2 of the line spacing of the FPC body 1 in the dense line area 101, wherein the line spacing of the FPC body 1 is 0.1mm.

[0040] 4. In one embodiment of the present invention, the clearance reserved at the edge of the flexible silicone protective pad 2 is 0.02mm, and the clearance is located between the flexible silicone protective pad 2 and the pad area and interface area of ​​the FPC body 1.

[0041] 5. In one embodiment of the present invention, the transparent puncture-resistant film 3 has a light transmittance of ≥90% and a thickness of 0.01mm.

[0042] 6. In one embodiment of the present invention, the flexible silicone protective pad 2 is bonded and fixed to the FPC body 1 by a high-temperature pressing process. The pressing temperature is 120℃±5℃, the pressing pressure is 0.3MPa, and the pressing time is 15s. Before pressing, the flexible silicone protective pad 2 is precisely aligned with the dense circuit area 101 of the FPC body 1 to ensure that there is a 0.02mm clearance between the edge of the pad and the pads and interface areas. After pressing, a visual inspection is performed to confirm that there are no bubbles or detachment between the pad and the FPC substrate, that the bonding is tight, that the circuit signal transmission is normal, and that the pads and interface areas are not obstructed.

[0043] 7. In one embodiment of the present invention, the transparent puncture-resistant film 3 is bonded to the FPC body 1 by a low-temperature bonding process and a rolling process, with a bonding temperature of 60℃±3℃. Before bonding, the transparent puncture-resistant film 3 is cut into an outline that matches the contact area 102 of the component; during the bonding process, the film is initially positioned on the surface of the FPC body 1 by low-temperature pre-bonding, and then compacted by a rolling process with a rolling pressure of 0.2MPa and a rolling speed of 5mm / s to ensure seamless bonding between the film and the FPC surface, with no wrinkles or bubbles on the surface, uniform backlight transmission, and a transmittance detection value ≥90%.

[0044] Working Principle: Example 1 addresses the risks of puncture and compression from burrs and sharp edges of the backlight guide plate in the densely packed wiring area 101 of the FPC body 1 during actual automotive backlight assembly. The component contact area 102 primarily bears the risk of friction and wear from front metal structural components and fasteners, as well as puncture from sharp foreign objects such as metal shavings. Buffer protection is achieved by attaching a flexible silicone protective pad 2 with a thickness of 0.05mm to 0.1mm to the densely packed wiring area 101. Furthermore, an ultra-thin transparent polyimide puncture-resistant layer with a thickness ≤0.03mm is composited and fixed in the component contact area 102. The membrane is designed for wear and puncture resistance. Two differentiated protective structures provide precise protection for the puncture risk type and puncture direction of their respective areas. Meanwhile, by controlling the thickness of the flexible silicone protective pad 2 to less than 1 / 2 of the line spacing and reserving a 0.02mm clearance, it is ensured that the lines are not obstructed and the electrical connection of the pads and interfaces is not affected. By controlling the maximum thickness of the transparent puncture-resistant film 3 to 0.03mm and the light transmittance to ≥90%, it is ensured that the backlight transmission is not affected. Thus, while achieving effective puncture protection, the bending flexibility and backlight transmission performance of the FPC body 1 are fully preserved.

[0045] As attached Figure 3 As shown:

[0046] Example 2:

[0047] This embodiment is basically the same as the previous embodiment, except that the flexible silicone protective pad 2 is a three-layer composite structure, including a bottom silicone gel buffer layer 201, a middle puncture-resistant skeleton layer 202 and a top wear-resistant protective layer 203.

[0048] The bottom silicone gel buffer layer 201 is directly attached to the surface of the FPC body 1;

[0049] The intermediate puncture-resistant skeleton layer 202 is a PI film or metal foil;

[0050] The top wear-resistant protective layer 203 is a polyurethane layer.

[0051] 1. In one embodiment of the present invention, the metal foil is copper foil or aluminum foil, and its thickness is 0.01 to 0.03 mm.

[0052] The fabrication process of the three-layer composite structure is as follows: First, a bottom silicone gel buffer layer 201 is formed on the lower surface of the intermediate puncture-resistant skeleton layer 202 through coating or lamination. Then, a top wear-resistant polyurethane layer is formed on the upper surface of the intermediate puncture-resistant skeleton layer 202 through coating or lamination, resulting in a three-layer composite flexible silicone protective pad layer 2 with a total thickness of 0.05mm to 0.1mm. This three-layer composite structure is then bonded and fixed to the surface of the dense circuit area 101 of the FPC body 1 through a high-temperature pressing process (pressing temperature 120℃±5℃, pressing pressure 0.3MPa, pressing time 15s).

[0053] Working Principle: During actual vehicle assembly and use, the densely packed FPC wiring area 101 may encounter extremely sharp foreign object punctures or accidental impacts from assembly tools. If only a single homogeneous flexible silicone protective pad 2 is used, it may be punctured due to its limited energy absorption capacity when facing large puncture forces, resulting in damage to the underlying wiring. Therefore, in Embodiment 2, the flexible silicone protective pad 2 is designed as a soft-hard-soft three-layer composite structure. The bottom silicone gel buffer layer 201 first absorbs and buffers the puncture impact energy, diffusing the point puncture force into surface stress. The middle PI film or metal foil skeleton layer serves as the core puncture-resistant load-bearing structure, utilizing its high tensile strength and tear resistance to effectively prevent further intrusion of sharp objects. The top wear-resistant polyurethane layer provides surface wear-resistant protection, preventing the pad itself from being worn thinner. The three-layer structure works synergistically to transform point puncture impacts into surface stress dispersion, significantly improving the overall puncture resistance strength. This effectively prevents damage to the FPC wiring from sharper foreign objects or accidental assembly tools, avoiding easy breakage of individual wiring.

[0054] Example 3:

[0055] This embodiment is basically the same as the previous embodiment, except that a microencapsulated repair agent is uniformly mixed inside the flexible silicone protective pad 2 and the transparent puncture-resistant film 3. The microencapsulated repair agent is configured such that when a micro-puncture wound occurs in the protective structure, the microcapsules rupture and release a repair medium. The repair medium can react with moisture in the air or a catalyst built into the substrate to automatically heal the micro-puncture wound. The preparation and mixing method of the microencapsulated repair agent is as follows: polyurea-formaldehyde or polyurethane is selected as the capsule wall material to encapsulate a liquid repair medium (such as dicyclopentadiene monomer or epoxy resin prepolymer), and microcapsules with a particle size of 5μm to 20μm are prepared by in-situ polymerization. During the molding process of the flexible silicone protective pad 2 or the transparent puncture-resistant film 3, the microcapsules are uniformly dispersed and mixed into the matrix material at a mass ratio of 3% to 8%, and the uniform distribution of the microcapsules in the matrix is ​​ensured by stirring or mixing processes.

[0056] Working Principle: Example 3 addresses the issue of micro-puncture wounds that may develop in FPC protective structures during long-term use due to micro-vibration fatigue, repeated friction, or accidental minor impacts. Without a self-healing solution, these micro-punctures will gradually expand over time, eventually leading to the failure of the protective layer and loss of its protective capability for the FPC. By pre-mixing a microencapsulated repair agent into the protective pad or puncture-resistant film substrate, when the protective structure suffers a minor puncture and develops a micro-puncture, the microcapsules around the puncture rupture due to mechanical stress, releasing the internal liquid repair medium. This repair medium fills the puncture gaps under capillary action and undergoes a polymerization and curing reaction upon contact with moisture in the air or a pre-added catalyst in the substrate, thereby automatically healing the micro-puncture wound, restoring the integrity and protective function of the protective structure, extending its service life, and further improving the long-term operational reliability of automotive backlight FPCs in harsh environments.

[0057] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A puncture-resistant protection structure for a vehicle-mounted backlight FPC, wherein the puncture-resistant protection structure is disposed on the surface of the FPC body (1), the FPC body (1) is divided into a dense wiring area (101) and a component contact area (102) corresponding to the vehicle-mounted backlight assembly condition, and the puncture-resistant protection structure is used to provide zoned protection for the easily punctured weak areas of the FPC body (1), characterized in that, The puncture-resistant protective structure includes: A flexible silicone protective pad (2) is attached and fixed to the surface of the densely packed line area (101). The thickness of the flexible silicone protective pad (2) is set to 0.05-0.1mm. Its outline matches the densely packed line area (101), and a clearance is reserved at the edge. A transparent puncture-resistant film (3) is fixed to the surface of the contact area (102) of the component. The transparent puncture-resistant film (3) is made of polyimide material.

2. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 1, characterized in that, The thickness of the flexible silicone protective pad (2) is less than 1 / 2 of the line spacing of the FPC body (1) in the dense line area (101), wherein the line spacing of the FPC body (1) is 0.1 to 0.2 mm.

3. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 1, characterized in that, The clearance reserved at the edge of the flexible silicone protective pad (2) is 0.02mm. The clearance is located between the flexible silicone protective pad (2) and the pad area and interface area of ​​the FPC body (1).

4. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 1, characterized in that, The transparent puncture-resistant film (3) has a light transmittance of ≥90% and a thickness of 0.01~0.03mm.

5. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 1, characterized in that, The flexible silicone protective pad (2) is bonded and fixed to the FPC body (1) by a high-temperature pressing process. The pressing temperature is 120℃±5℃, the pressing pressure is 0.3MPa, and the pressing time is 15s.

6. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 1, characterized in that, The transparent puncture-resistant film (3) is bonded to the FPC body (1) by a low-temperature bonding process and a rolling process, with a bonding temperature of 60℃±3℃.

7. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 1, characterized in that, The flexible silicone protective pad layer (2) is a three-layer composite structure, including a bottom silicone gel buffer layer (201), a middle puncture-resistant skeleton layer (202), and a top wear-resistant protective layer (203). The bottom silicone gel buffer layer (201) is directly attached to the surface of the FPC body (1); The intermediate puncture-resistant skeleton layer (202) is a PI film or metal foil; The top abrasion-resistant protective layer (203) is a polyurethane layer.

8. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 7, characterized in that, The metal foil is copper foil or aluminum foil, and its thickness is 0.01 to 0.03 mm.

9. The puncture-resistant protection structure for a vehicle-mounted backlight FPC according to claim 1, characterized in that, The flexible silicone protective pad (2) and the transparent puncture-resistant film (3) are uniformly mixed with microencapsulated repair agents.

Images