How does the internal structure of 3A explosion-proof film disperse impact force when preventing screen breakage due to external impact?
Publish Time: 2026-01-30
As a high-end screen protector, 3A explosion-proof film's core value lies not only in daily scratch resistance, high light transmittance, and fingerprint resistance, but also in "explosion-proof"—effectively preventing the original glass screen from shattering and flying when devices such as mobile phones and tablets are subjected to sudden external forces such as drops or impacts, ensuring user safety and reducing repair costs. The key to achieving this function lies in its unique multi-layer composite internal structure design, which, through the synergistic effect of material properties and mechanical mechanisms, efficiently disperses, absorbs, and dissipates impact energy.1. Multi-layer Composite Structure: Constructing a Gradient Buffer SystemA typical 3A explosion-proof film is usually composed of 4–7 layers of functional materials hot-pressed together, forming a "hard-soft-hard" or "soft-tough-adhesive" gradient structure. The outermost layer is a high-hardness coating with a Mohs hardness of 6–9H, designed to resist scratches from everyday items like keys and grit. The core layer uses high-toughness thermoplastic polyurethane or specially modified PET, offering excellent ductility and resilience. The bottom layer is made of high-adhesion silicone or OCA optical adhesive, ensuring complete adhesion to the screen and allowing for traceless removal. This layered design allows the film to buffer impacts gradually rather than rigidly resist them.2. Impact Dispersion Mechanism: From Point Load to Surface DiffusionWhen a sharp or hard object strikes the screen, the impact force initially concentrates at a tiny point of contact. The highly elastic TPU middle layer of the 3A explosion-proof film plays a crucial role at this moment: its molecular chains rapidly stretch and slide under instantaneous high pressure, converting localized high stress into large-scale deformation energy, which then rapidly diffuses laterally along the film plane. This "stress wave diffusion effect" significantly reduces the peak pressure per unit area, preventing stress concentration from being directly transmitted to the brittle glass substrate below. Experiments show that high-quality 3A film can reduce point impact pressure by more than 60%, effectively "diluting" the energy that would otherwise be enough to penetrate glass.3. Energy Absorption and Dissipation: Internal Friction Converts Energy into Kinetic EnergyBesides dispersion, 3A explosion-proof film also dissipates energy through internal friction within the material. During repeated stretching and rebound, irreversible slippage and internal friction occur between molecules in polymer materials such as TPU, converting some of the impact kinetic energy into heat. Simultaneously, the micro-viscoelasticity between multi-layer interfaces also dampens the propagation of vibration waves, suppressing secondary impacts. Furthermore, some high-end products embed nanoscale energy-absorbing microspheres or honeycomb microstructures within the TPU layer, further increasing the energy absorption density per unit volume, forming a "microscopic buffer cavity" that effectively intercepts crack propagation paths.4. Overall Synergistic Protection: Dual Protection Against Shattering and SplashingEven if the original glass develops microcracks due to extreme impact, the 3A explosion-proof film still provides a safety net. Its highly adhesive bottom layer firmly anchors glass fragments, while the highly elongated middle layer acts like a "flexible net," enveloping the fractured area to prevent flying fragments from injuring people or exacerbating damage. This "unbreakable yet stable" characteristic is the origin of its "explosion-proof" name. Compared to ordinary tempered glass screen protectors that shatter into a spiderweb pattern and easily detach, 3A explosion-proof film, even when broken, maintains a generally flat surface, and touch functionality remains unaffected, giving users time to replace it.In summary, 3A explosion-proof film does not rely on the strength of a single material to withstand impacts. Instead, through a scientifically designed multi-layered structure, it constructs a dynamic protection system integrating "dispersion, absorption, and constraint." Each internal layer performs its function and responds collaboratively, completing the conversion and control of impact energy within milliseconds, thus significantly improving the screen's drop and explosion resistance in real-world usage scenarios. For this reason, 3A explosion-proof film has become the preferred solution for screen protection of high-end smartphones, automotive displays, and industrial handheld devices.
