Controllable-cracking car door glass and manufacturing method thereof

Abstract

The invention belongs to the technical field of automobile safety, and discloses controllable-fracture automobile door glass and a manufacturing method thereof.The interior and the surface of the glass are provided with preset areas, the preset areas are internally provided with non-penetrable stress guiding structures, the stress guiding structures are composed of micron-sized modified points or micro cracks generated through laser induction, and the micro-sized modified points or micro cracks are distributed in the preset areas. The stress guide structure has a spatial arrangement mode, and under the action of collision stress, the stress guide structure induces cracks to expand along the spatial arrangement mode. According to the invention, in a preset area in the glass, femtosecond laser is utilized to induce and form micron-sized modified points or micro cracks with a specific spatial arrangement mode, and a non-penetrating stress guide structure is formed, so that the cracks are induced to expand along a preset path under collision stress and are broken into a plurality of large fragments with passivated edges; and rapid removal is facilitated to form an escape opening. The key point of the manufacturing method of the glass is that laser scanning is performed firstly, and then toughening treatment is performed, so that the unification of the daily strength of the glass and the controllable cracking function during collision is ensured.

Description

Technical Field

[0001] This invention belongs to the field of automotive safety technology, and specifically relates to a controllable cracking car door glass and its manufacturing method. Background Technology

[0002] In car collisions, especially side impacts, rollovers, or submersion in water, the ability of car door windows to quickly and safely create an effective escape route is crucial to improving the survival rate of occupants. Traditional car door windows primarily use two technologies: tempered glass and laminated glass. While each has its own emphasis on safety design, both have inherent drawbacks.

[0003] Tempered glass shatters into numerous small, blunt-angled particles when broken, reducing the risk of secondary injuries from flying shards. However, occupants and rescuers must painstakingly clean up the large amount of adhered glass particles, which is extremely disadvantageous in time-sensitive rescue scenarios. The biggest advantage of laminated glass is that the fragments are adhered by the adhesive layer after breakage, so they are unlikely to fly and injure people. However, this also means that it remains almost structurally intact in an accident. It is strong and difficult to remove as a whole, requiring external tools (such as window breakers) to forcefully penetrate it, which seriously hinders rapid escape in emergency situations.

[0004] Therefore, in existing technologies, mechanical window breakers are usually pre-installed inside the car door. During a collision, the energy is transferred to the window breaker by the deformation of the car door structure, thereby shattering the glass. However, this solution relies on the deformation of the car door to conduct energy, which has response delays and uncertainties, and increases the complexity of the car door structure and the space occupied. For vehicles equipped with window glass striking devices, occupants still need to manually operate them in an emergency to trigger the built-in striking pin to shatter the glass. However, in a serious collision, occupants may be unable to operate them effectively due to unconsciousness, injury, or panic, causing the active escape device to fail.

[0005] Therefore, there is an urgent need in the field for a new type of car door glass technology that can automatically and reliably break in a predetermined manner upon collision, controlling the hazards of fragments while quickly forming a sufficiently large escape opening. Summary of the Invention

[0006] To address the contradiction between the two core requirements of "collision safety protection" and "emergency escape efficiency" in existing automotive door glass technology, as mentioned above, this invention provides a controllable breakage door glass and its manufacturing method.

[0007] To achieve the above objectives, the present invention provides the following technical solution: First, the present invention provides a controllable crackable car door glass, wherein the interior and surface of the glass are provided with preset areas, and the preset areas are provided with stress guiding structures; The stress-guiding structure is composed of micron-sized modified points or microcracks induced by laser, and has a spatial arrangement pattern. Under impact stress, the stress-guiding structure induces cracks to propagate along the spatial arrangement pattern.

[0008] Further configuration: The preset area includes an edge buffer zone located at the edge of the glass and a central crack zone located in the middle of the glass.

[0009] Further configuration: The central crack zone divides the glass into multiple main areas, including intersecting cross-shaped zones, a ring-shaped crack zone, and an escape zone. The escape zone is surrounded by the ring-shaped crack zone, and the cross-shaped zones are located within the escape zone.

[0010] Further configuration: The central fracture zone also includes impact-sensitive points, which are distributed in the internal area of ​​the escape zone and intersect or surround the cross-shaped zone in the central area of ​​the glass.

[0011] Further configuration: The spatial arrangement pattern is at least one of dot matrix, linear matrix, or grid.

[0012] Further settings: The influence depth of the micron-level modification points or microcracks below the glass surface is set as H, satisfying: 50μm≤H≤300μm.

[0013] Secondly, the present invention provides a method for manufacturing controllable breakage vehicle door glass as described above, specifically including the following steps: Provide raw glass sheets; Laser scanning: A short pulse laser is used to scan a predetermined area of ​​the glass substrate to form the stress-guided structure; Tempering: Tempering glass after laser processing.

[0014] Further configuration: In the laser scanning step, the ultrashort pulse laser is a femtosecond laser; The laser wavelength of the femtosecond laser is set to λ, which satisfies 500nm≤λ≤1100nm, and the pulse energy of the femtosecond laser is set to E, which satisfies 10μJ≤E≤50μJ.

[0015] Further setting: In the laser scanning step, the spacing between the micron-level modification points or microcracks formed by the laser scanning is set to D, which satisfies 0.3mm≤D≤1.5mm.

[0016] Compared with the prior art, the present invention has the following advantages: 1. This invention uses laser processing to create a pre-set stress-guiding structure area and then tempers it, so that when the glass is subjected to impact stress, it does not shatter randomly, but rather expands along the pre-set micro-cracks, breaking into several large fragments with blunted edges and regular size. This effectively avoids small fragments flying and injuring people, and also allows the glass as a whole or in large pieces to be easily pushed away from the window frame, thereby forming an escape channel of sufficient size within seconds, greatly improving rescue efficiency.

[0017] 2. The glass breaking process designed in this invention is automatically triggered by impact stress and relies on the embedded stress guiding structure. It requires no electricity or human intervention. Even in extreme cases where the occupants are unconscious or panicked, the escape route can still be automatically formed, ensuring the absolute reliability of the function.

[0018] 3. The stress-guiding structure of the present invention is a non-penetrating micron-level modification, and after subsequent tempering treatment, the microcrack tips are blunted. Therefore, in normal conditions, it has high strength and high safety comparable to traditional tempered glass, without affecting optical performance and the original structure of the vehicle, thus achieving a balance between functionality and durability.

[0019] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the planar structure of the car door glass of the present invention is shown; Figure 2 A flowchart illustrating the manufacturing method of the controllable fracture door glass of the present invention is shown.

[0022] In the diagram: 1. Edge buffer zone; 2. Circular rupture zone; 3. Escape zone; 4. Cross-shaped zone; 5. Impact-sensitive point. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0025] First, this invention provides a controllable cracking car door glass: like Figure 1 As shown, the glass has a preset area inside and on the surface, and a stress guiding structure is provided in the preset area. The preset area includes an edge buffer zone 1 located at the edge of the glass and a central crack zone located in the middle of the glass. In this embodiment, by setting specific preset areas and stress guiding structures inside and on the surface of the glass, the car door glass can achieve a controllable fracture mode when it is hit. The edge buffer zone 1 in the preset area is located at the edge of the glass and its main function is to absorb and disperse the impact force from the edge. In this embodiment, when the glass is impacted from the edge, the edge buffer strip 1 is designed to guide the stress, causing it to crack or deform preferentially at that point, thereby protecting the central area of ​​the glass from the impact or reducing stress concentration in the central area.

[0026] Furthermore, the central fracture zone divides the glass into multiple main areas, including intersecting cross-shaped zones 4 and a ring-shaped fracture zone 2, an escape zone 3, and impact-sensitive points 5. The escape zone 3 is surrounded by the ring-shaped fracture zone 2, the cross-shaped zones 4 are located in the inner area of ​​the escape zone 3, and the impact-sensitive points 5 are distributed in the inner area of ​​the escape zone 3 and are intersected or surrounded by the cross-shaped zones 4 in the middle of the glass. In this embodiment, the escape zone 3 is surrounded by the annular crack zone 2 and is located in the middle area of ​​the glass. Its main function is to provide a safe escape route. The annular crack zone 2 is located in the middle area of ​​the glass and is arranged in a ring. When the glass is subjected to a sufficiently large impact force (especially the stress concentrated in the center or transmitted through the cross-shaped strip 4), the annular crack zone 2 can effectively disperse and release the stress concentrated in the center, preventing the glass from catastrophically breaking due to excessive stress. It allows the glass to break in a preset manner, forming an annular crack line or crack area. Controllable cracking is formed in a specific area, thereby controlling the crack range and pattern of the glass, rather than random overall breakage. In this embodiment, the cross-shaped band 4 is also located in the middle area of ​​the glass. When the glass is impacted, the cross-shaped band 4 area will break in a preset manner to form intersecting fracture lines, dividing the glass into multiple relatively small areas or fragments, further refining and controlling the glass fracture mode, making the fracture more uniform and predictable, and can be combined with the annular fracture band 2 to form a more complex stress release path, improving the safety of the glass when it is impacted from various directions. In this embodiment, the impact-sensitive point 5 is a region in the glass structure that is particularly sensitive to impact. It is distributed in the internal area of ​​the escape zone 3 and is arranged to intersect or surround the middle of the glass with the cross-shaped band 4. When impacted, it becomes the starting point of stress concentration, triggering a preset fracture mode. It can precisely control the starting point and propagation path of glass fracture, ensuring that the glass fractures in the designed manner when impacted. By setting the impact-sensitive point 5, the overall impact resistance and fracture morphology of the glass can be optimized.

[0027] Furthermore, a non-penetrating stress guiding structure is provided within the preset area. The stress guiding structure is composed of micron-level modification points or microcracks generated by laser induction and has a spatial arrangement pattern. In this embodiment, the stress-guided structure is designed as a network of microscopic weak points in three-dimensional space. By utilizing the "stress concentration" effect in materials science, and by pre-setting controllable microscopic defects in the glass matrix, the initiation and propagation path of macroscopic cracks is actively guided, thereby transforming random and dangerous breakage into controllable and safe directional breakage. In this embodiment, the micron-scale modification points or microcracks in the stress-guided structure are precisely formed by high-energy beams such as femtosecond lasers at the focal point inside the glass. The laser energy causes physical or chemical changes in the glass material within a very small volume (micron scale) of the focal region, or directly generates tiny internal cracks. These modification points or microcracks are non-penetrating, meaning they exist inside the glass but do not penetrate to the surface. Therefore, they do not affect the original appearance, light transmittance, and feel of the glass, nor do they affect the glass's daily use strength and optical performance. In this embodiment, macroscopically, these micro-points are equivalent to embedding a large number of regularly distributed "weak points" with strengths far lower than the matrix into homogeneous glass. When the impact stress wave propagates in the glass, it will preferentially generate huge stress concentrations at these preset "weak points", making them the only starting point for crack initiation and ensuring the predictability and repeatability of the fracture behavior.

[0028] Furthermore, the spatial arrangement pattern is at least one of lattice, linear array or grid, and the influence depth of the micron-level modified points or microcracks below the glass surface is set as H, satisfying: 50μm≤H≤300μm; In this embodiment, under the action of collision stress, the stress-guided structure induces cracks to propagate along a spatial arrangement pattern. A single micro-point can only determine where the crack starts, while the spatial arrangement pattern of the micro-points determines the propagation path of the crack. When the distance between the points is close enough, the crack will propagate from one point to the next, "points connect to form a line", thus forming a fracture path, and the crack will stably propagate along this path. In this embodiment, controlling the depth H of the modified point or microcrack to 50-300μm is a key design parameter that has been experimentally verified. This depth is much smaller than the typical glass thickness of 3.5-5mm and can effectively guide the crack. If the depth is too shallow (H<50μm), the stress guiding structure may not be able to effectively guide the propagation of the internal crack. If it is too deep (H>300μm), it may excessively weaken the overall mechanical properties of the glass, affecting its strength and safety in daily use.

[0029] Secondly, the present invention provides a method for manufacturing a controllable fracture vehicle door glass as described above: like Figure 2 As shown, the method for manufacturing controllable fracture-resistant car door glass also includes the following steps: S1. Provide raw glass sheets; In step S1, sodium-calcium silicate flat glass sheets that meet automotive glass standards are selected and pre-treated by cutting, edge grinding, and cleaning to ensure that the substrate is clean and dimensionally accurate, providing a qualified base for subsequent precision processing.

[0030] S2. Laser scanning: Using an ultrashort pulse laser to scan a preset area of ​​the glass substrate to form a stress-guided structure; In step S2, the ultrashort pulse laser is a femtosecond laser. The laser wavelength of the femtosecond laser is set to λ, which satisfies 500nm≤λ≤1100nm. Wavelengths within this range have moderate penetration and nonlinear absorption efficiency for glass, which can efficiently form modification points or microcracks inside, while ensuring that the processing is stable and controllable. In step S2, the pulse energy of the femtosecond laser is set to E, which satisfies 10μJ≤E≤50μJ. Pulse energy within this range can ensure the generation of micron-sized modification points or microcracks with uniform size and regular shape. If the energy is too low, the glass cannot be effectively modified. If the energy is too high, the damage area may be too large or irregular, or even cause the glass to break. In step S2, the spacing between the micron-level modified points or microcracks formed by laser scanning is set to D, which satisfies 0.3mm≤D≤1.5mm. The spacing D determines the length of the "bridge" that needs to be connected when the crack propagates. It is a key parameter for controlling the size of the fragments after fracture. The spacing D within this range can ensure that the cracks can be stably "connected into a line" and form sufficiently large fragments. If the spacing is too small, the fragments will still be too small. If the spacing is too large, the crack may not propagate along the predetermined path.

[0031] S3. Tempering treatment: Tempering glass after laser processing; In step S3, the tempering process is either physical or chemical, which forms a compressive stress layer on the glass surface and a tensile stress layer inside. While improving the overall strength of the glass, the compressive stress generated by the tempering process will passivate the micron-level modification points or microcrack tips pre-fabricated by the laser. This ensures that the modification points or microcracks can act as stress concentration points to initiate cracking upon impact, while also preventing them from spontaneously expanding due to stress concentration during daily use, thereby ensuring the high strength and reliability of the glass under normal conditions.

[0032] In this embodiment, the glass must be tempered after laser processing. If it is tempered first, the subsequent laser processing will destroy the uniform stress field formed by tempering, resulting in severe unevenness in glass strength or even spontaneous breakage. Tempering afterward ensures the integrity of the pre-set fragile structure.

[0033] In this embodiment, after step S3, the tempered glass also needs to be inspected, cleaned, and packaged.

[0034] The following describes a method for manufacturing controllable breakage car door glass through specific embodiments.

[0035] Example 1: S1. Provide raw glass sheets: Select 4.0mm thick sodium-calcium silicate flat glass, which is cut, edged, cleaned and dried before use.

[0036] S2. Laser Scanning: A femtosecond laser with a wavelength λ of 1030nm is used to process the original glass sheet. The laser focus is precisely controlled at 100μm below the glass surface. The laser pulse energy E is set to 25μJ, the repetition frequency is 200kHz, and the scanning speed is 500mm / s. The scanning is performed according to the preset area, and the resulting dot spacing D=0.8mm. Under these parameters, a uniform and regular micron-level modified dot array can be formed inside the glass to form a stress-guided structure.

[0037] S3. Tempering treatment: The laser-scanned glass is sent into a tempering furnace for physical tempering treatment. The temperature is heated to 680℃, and then it is rapidly cooled by air to form high pressure stress on the glass surface, while the modified point tips generated in step S2 are passivated.

[0038] After step S3, the tempered glass is inspected, cleaned, and packaged.

[0039] Example 2: The difference from Example 1 lies in the specific settings of steps S2 and S3; S2. Laser scanning: A femtosecond laser with a wavelength λ of 515nm is used to process the glass substrate. The laser focus is precisely controlled at 80μm below the glass surface. The laser pulse energy E is set to 40μJ, the repetition frequency is 100kHz, the scanning speed is 200mm / s, and the resulting dot spacing D=0.4mm. Under these parameters, a uniform and regular micron-scale modified dot array can be formed inside the glass to form a stress-guided structure.

[0040] S3. Tempering treatment: Tempering is carried out by chemical ion exchange. The glass is immersed in potassium nitrate molten salt at 410℃ for 3 hours, so that sodium ions on the glass surface exchange with potassium ions in the molten salt to form a surface compressive stress layer.

[0041] Laboratory drop hammer impact tests were conducted on the glass samples prepared in Examples 1 and 2 above. The results showed that the fracture initiation point of all samples appeared precisely in the preset stress-guided area, and the crack propagation path matched the preset pattern with a degree of more than 90%. Compared with ordinary tempered glass, the average area of ​​the main fragments produced by the glass samples increased by 5-8 times, and the sharpness of the fragment edges was reduced by more than 60% as shown by the TSP test.

[0042] In addition, the glass samples prepared in Examples 1 and 2 were tested for optical distortion, impact strength, heat resistance and weather resistance in accordance with automotive safety glass standards. The results showed that laser processing and subsequent tempering did not adversely affect the conventional performance of the glass.

[0043] In summary, this invention, through an optimized manufacturing method for controllable breakage car door glass, has successfully produced a car door glass that combines high daily safety with excellent emergency escape functionality.

[0044] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A controllable breakage vehicle door glass, characterized in that, The glass has a preset area inside and on its surface, and a non-penetrating stress guiding structure is provided within the preset area; The stress-guiding structure is composed of micron-sized modified points or microcracks induced by laser, and has a spatial arrangement pattern. Under impact stress, the stress-guiding structure induces cracks to propagate along the spatial arrangement pattern. The glass is tempered to become tempered glass.

2. The controllable breakage car door glass according to claim 1, characterized in that, The preset area includes an edge buffer zone (1) located at the edge of the glass and a central crack zone located in the middle of the glass.

3. The controllable breakage car door glass according to claim 2, characterized in that, The central fracture zone divides the glass into multiple main areas, including intersecting cross zones (4), a ring-shaped fracture zone (2), and an escape zone (3).

4. The controllable breakage car door glass according to claim 3, characterized in that, The escape zone (3) is surrounded by the annular rupture zone (2), and the cross zone (4) is located in the inner area of ​​the escape zone (3).

5. The controllable breakage car door glass according to claim 3, characterized in that, The central fracture zone also includes impact-sensitive points (5), which are distributed in the internal area of ​​the escape zone (3) and intersect or surround the cross-shaped zone (4) in the central area of ​​the glass.

6. The controllable breakage car door glass according to claim 1, characterized in that, The spatial arrangement pattern is at least one of dot matrix, linear matrix, or grid.

7. The controllable breakage car door glass according to claim 1, characterized in that, The influence depth of the micron-level modification point or microcrack below the glass surface is defined as H, which satisfies: 50μm≤H≤300μm.

8. A method for manufacturing a controllable fracture vehicle door glass as described in any one of claims 1-7, characterized in that, Includes the following steps: Provide raw glass sheets; Laser scanning: A short pulse laser is used to scan a predetermined area of ​​the glass substrate to form the stress-guided structure; Tempering: Tempering glass after laser processing.

9. A method for manufacturing a controllable fracture vehicle door glass according to claim 8, characterized in that, In the laser scanning step, the ultrashort pulse laser is a femtosecond laser; The laser wavelength of the femtosecond laser is set to λ, which satisfies 500nm≤λ≤1100nm, and the pulse energy of the femtosecond laser is set to E, which satisfies 10μJ≤E≤50μJ.

10. A method for manufacturing a controllable fracture vehicle door glass according to claim 8, characterized in that, In the laser scanning step, the spacing between the micron-level modification points or microcracks formed by the laser scanning is set as D, which satisfies 0.3mm≤D≤1.5mm.

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