Method for manufacturing glass for automobile window, method for manufacturing laminated glass for automobile window, glass for automobile window, and laminated glass for automobile window

Abstract

This method for manufacturing glass for an automobile window includes forming, at intervals, a plurality of processed parts (50) including cracks (56) that reach a surface of a glass plate, by irradiating the surface of the glass plate with laser light. The intensity distribution of energy on the surface of the glass plate imparted by the irradiation of the laser light for forming one processed part has a non-axisymmetric shape.

Description

Manufacturing method for automobile window glass, manufacturing method for laminated automobile window glass, automobile window glass, and laminated automobile window glass

[0001] The present disclosure relates to a method for manufacturing automotive window glass, a method for manufacturing laminated automotive window glass, automotive window glass, and laminated automotive window glass.

[0002] There is a need for technology that reduces impact on people, such as pedestrians, when a vehicle collides with them. For example, Japanese Patent Application Laid-Open Publication No. 2017-213928 (Patent Document 1) describes a technology in which, when an impact is applied to the periphery of the cowl louvers and windshield, the rear end of the cowl louvers and the front end of the windshield, which are connected by a molding, are separated, thereby reducing the impact on the person.

[0003] Automotive window glass is required to break appropriately to reduce the impact on a person, such as a pedestrian, during a collision between a vehicle and the person. For example, laminated automotive window glass is required to have a Head Injury Criterion (HIC) of a desired value or less. On the other hand, automotive window glass is also required to allow vehicle occupants to view the outside of the vehicle through the automotive window glass.

[0004] One aspect of the present invention provides a technology that reduces the impact on a person when a vehicle collides with the person, while not interfering with the vehicle occupants' ability to see outside the vehicle.

[0005] One aspect of the present invention is a method for manufacturing a glass sheet for an automobile window, which includes irradiating a surface of a glass sheet with laser light to form a plurality of processed portions at intervals, each including a crack that reaches the surface of the glass sheet, and in which the energy intensity distribution on the surface of the glass sheet imparted by the laser light irradiation to form one of the processed portions has a non-axisymmetric shape.

[0006] Another aspect of the present invention is a method for manufacturing laminated glass for automobile windows, the laminated glass for automobile windows comprising, from the vehicle exterior side toward the vehicle interior side, a first glass sheet, an interlayer film, and a second glass sheet, in this order; the method includes irradiating a surface of the first glass sheet and / or the second glass sheet on the vehicle interior side with laser light to form a plurality of processed portions at intervals, the processed portions including cracks that reach the surface of the first glass sheet and / or the second glass sheet; and the energy intensity distribution on the surface of the glass sheet, imparted by the laser light irradiation to form one processed portion, has a non-axisymmetric shape.

[0007] Furthermore, one aspect of the present invention is an automobile window glass having a plurality of processed portions formed at intervals on the surface of a glass plate, the processed portions including recesses and cracks formed around the recesses and reaching the surface of the glass plate, and the recesses have a major axis and a minor axis in a planar view.

[0008] According to one aspect of the present invention, it is possible to provide a technology that reduces the impact on a person when a vehicle collides with the person, while not interfering with the vehicle occupants' ability to see outside the vehicle.

[0009] FIG. 5a is a front view of an automobile equipped with an automobile window glass manufactured by a manufacturing method according to an embodiment; FIG. 6a is a cross-sectional view of an automobile window glass that is laminated glass, and is a view for explaining breakage of the laminated glass when an automobile collides with a pedestrian; FIG. 7a shows an example of a processing device used in a manufacturing method for automobile window glass according to an embodiment; FIG. 8a is a plan view of an automobile window glass manufactured by a manufacturing method according to an embodiment; FIG. 9a is an enlarged view of a portion I including one processed portion in FIG. 4; FIG. 5a is a cross-sectional view taken along line II-II of FIG. 5a; FIG. 5a is a cross-sectional view taken along line III-III of FIG. 5a; FIG. 9a is a view for explaining sweep irradiation; FIG. 9a is an enlarged plan view of a processed portion formed in another example; FIG. 9a is a cross-sectional view taken along line IV-IV of FIG. 7a; FIG. 9a is an enlarged plan view of a modified example of the processed portion in FIG. 5a; FIG. 9a is a cross-sectional view taken along line V-V of FIG. 8a; FIG. 9a is a plan view image of one processed portion formed in Example 1;

[0010] Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0011] First, the basic structure of an automotive window glass manufactured according to one embodiment of the present invention will be described. Figure 1 shows an example in which an automotive window glass 1 is used as a window glass for an automobile 100. In the example of Figure 1, the automotive window glass 1 is a glass installed in an opening (window) at the front of a body 2 of the automobile 100, i.e., a windshield. The automotive window glass 1 may also be used as window glass other than a windshield, for example, a side glass, a rear glass, or a roof glass.

[0012] The automotive window glass 1 may be a glass plate made of inorganic glass. Examples of inorganic glass include soda lime silicate glass, aluminosilicate glass, borate glass, lithium aluminosilicate glass, and borosilicate glass. The method for forming the glass plate made of inorganic glass is not particularly limited. The glass plate is preferably formed by, for example, a float process (float glass). The glass plate may be untempered glass, which is formed by shaping molten glass into a plate shape and slowly cooling it, or tempered glass, which has been tempered. The tempering process may be an air-cooling tempering process, a chemical tempering process, or the like. Even if untempered glass breaks or cracks upon impact, it is less likely to develop fine cracks or fissures across the entire surface, ensuring visibility for occupants in the event of an accident.

[0013] The automotive window glass 1 may be a single pane of glass for automotive windows or a laminated glass for automotive windows (hereinafter also referred to as laminated glass). Single pane glass is composed of one of the above-mentioned glass plates, while laminated glass is composed of two or more of the above-mentioned glass plates combined together. As shown in FIG. 2 , the laminated glass may include a first glass plate 11, an interlayer film 30, and a second glass plate 12, in this order, from the exterior side to the interior side of the vehicle. The first glass plate 11 and the second glass plate 12 are joined together by the interlayer film 30. The first glass plate 11 has a first surface F1 facing the exterior side of the vehicle and a second surface F2 facing the interior side of the vehicle. The second glass plate 12 has a third surface F3 facing the exterior side of the vehicle and a fourth surface F4 facing the interior side of the vehicle. The first glass plate 11 and the second glass plate 12 in the laminated glass are also simply referred to as glass plates 10.

[0014] When the automotive window glass 1 is a single-pane glass, the thickness of the glass plate may be 0.2 mm or more and 5 mm or less. When the automotive window glass 1 is a laminated glass, the thicknesses of the first glass plate 11 and the second glass plate 12 may be the same or different from each other. The thickness of the first glass plate 11 may be 1.1 mm or more and 4.2 mm or less. The thickness of the second glass plate 12 may be 0.5 mm or more and 2.7 mm or less. Furthermore, the thickness of the entire laminated glass may be 2.3 mm or more and 8.0 mm or less. The materials, manufacturing methods, etc. of the first glass plate 11 and the second glass plate 12 may be the same or different from each other.

[0015] The material of the interlayer film 30 is not particularly limited, but a thermoplastic resin is preferred. Examples of materials for the interlayer film 30 include thermoplastic resins such as plasticized polyvinyl acetal resins, plasticized polyvinyl chloride resins, saturated polyester resins, plasticized saturated polyester resins, polyurethane resins, plasticized polyurethane resins, ethylene-vinyl acetate copolymer resins, ethylene-ethyl acrylate copolymer resins, cycloolefin polymer resins, and ionomer resins. Resin compositions containing modified hydrogenated block copolymers, as described in Japanese Patent No. 6065221, are also suitable. Among these, plasticized polyvinyl acetal resins are preferred because of their excellent balance of properties such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. The above thermoplastic resins may be used alone or in combination. The term "plasticized" in the context of the plasticized polyvinyl acetal resin refers to plasticization achieved by the addition of a plasticizer. The same applies to other plasticized resins.

[0016] The interlayer film 30 may be a resin that does not contain a plasticizer, such as an ethylene-vinyl acetate copolymer resin. Examples of the polyvinyl acetal resin include polyvinyl formal resin obtained by reacting polyvinyl alcohol (PVA) with formaldehyde, polyvinyl acetal resin in the narrow sense obtained by reacting PVA with acetaldehyde, and polyvinyl butyral resin (PVB) obtained by reacting PVA with n-butylaldehyde. PVB is particularly suitable because of its excellent balance of properties such as transparency, weather resistance, strength, adhesive strength, penetration resistance, impact energy absorption, moisture resistance, heat insulation, and sound insulation. The above resins may be used alone or in combination.

[0017] The interlayer film 30 may have either a single layer structure or a multi-layer structure. The interlayer film 30 may have a function other than adhesion. For example, the interlayer film 30 may have one or more layers selected from a sound-insulating layer, a colored transparent layer, an ultraviolet-blocking layer, an infrared-blocking layer, and the like.

[0018] The thickness of the intermediate film 30 may be 0.5 mm or more from the viewpoint of adhesiveness. The thickness of the intermediate film 30 may be 3 mm or less from the viewpoint of lightness and ease of handling. The thickness of the intermediate film 30 may be constant or may vary depending on the position.

[0019] As shown in Figure 2, the automotive window glass 1 may be curved entirely or partially so as to be convex toward the exterior of the vehicle. When the automotive window glass 1 is a laminated glass, the first glass sheet 11 and the second glass sheet 12 may each be processed and curved to a desired predetermined curvature in one or two directions by bending. When the automotive window glass 1 is used as a windshield as shown in Figure 1, it is complexly curved in the fore-aft and abrupt directions of the vehicle, but it may also be single-curved in only the fore-aft or abrupt direction. The radius of curvature of the automotive window glass 1 or glass sheet 10 may be 200 mm or more and 300,000 mm or less.

[0020] As shown in FIG. 1 , a shielding layer 40 may be provided around the periphery of the automotive window glass 1 to protect a sealant or other material that adheres and holds the automotive window glass 1 to the vehicle body 2. The shielding layer 40 can be formed, for example, by applying and firing a low-brightness ceramic color paste, such as black, gray, or brown, containing a black pigment and a fusible glass frit. The shielding layer 40 may be provided on the interior side of the automotive window glass 1. If the automotive window glass 1 is laminated glass, the shielding layer 40 may be formed on one or more of the second surface F2, third surface F3, and fourth surface F4 ( FIG. 2 ) of the laminated glass, preferably on the periphery of at least one of the second surface F2 and fourth surface F4 ( FIG. 2 ). The shielding layer 40 may extend from 10 mm to 300 mm from the peripheral edge of the glass sheet. In this embodiment, the area of ​​the automotive window glass 1 other than the area covered by the shielding layer 40 constitutes the see-through area 5. The perspective area 5 is an area that allows the occupants of the automobile 100 to see the outside of the automobile 100. In other words, the occupants of the automobile 100 can see the outside of the automobile 100 through the perspective area 5.

[0021] As described above, the automotive window glass 1 is required to break appropriately in order to reduce the impact on a person such as a pedestrian or cyclist when the automobile collides with the person. For example, the automotive window glass 1 is required to have a Head Injury Criterion (HIC) of a desired value or less (for example, 1,000 or less, preferably 650 or less).

[0022] Here, we will explain how the automotive window glass 1 breaks when it collides with a person. Figure 2 shows a simulation of a collision between a laminated automotive window glass and a person. As shown in Figure 2, when a person 200 collides with the laminated automotive window glass 1, the automotive window glass 1 is pushed from the outside toward the inside of the vehicle. As a result, tensile stress is generated on the second surface F2 of the first glass sheet 11, which is the surface facing the vehicle interior. If the second surface F2 contains a portion that is different from the average properties of glass sheets, or that has been modified or deformed, the first glass sheet 11 is likely to break from that portion. Furthermore, tensile stress is also generated on the fourth surface F4 of the second glass sheet 12, which is the surface facing the vehicle interior. If the fourth surface F4 contains a portion that is different from the average properties of glass sheets, or that has been modified or deformed, the second glass sheet 12 is likely to break from that portion. In this way, when an impact is applied to the window glass of an automobile from outside the vehicle, cracking (fracture) is likely to initiate on the inside of the glass plate 10 and then progress from the inside to the outside of the vehicle. Furthermore, because the fourth surface F4 of the second glass plate 12, which is the surface facing the inside of the vehicle, is exposed, cracking is particularly likely to initiate from the fourth surface F4 of the automobile window glass 1 as a whole.

[0023] In a method for manufacturing automotive window glass according to one embodiment of the present invention, a processed portion including a crack reaching the surface of the glass sheet is formed by irradiating the surface with laser light, as a portion that is differentiated from the average properties of the glass sheet. Specifically, by irradiating the surface of the glass sheet with laser light, multiple processed portions including cracks reaching the surface are formed at intervals. Laser light has high directivity or convergence, and can be irradiated with a small irradiation spot diameter (diameter at the focused position). Therefore, a minute region can be locally heated, and processed portions can be formed with precise size and arrangement. Furthermore, in this embodiment, multiple processed portions are formed at intervals on the surface of the glass sheet.

[0024] FIG. 3 shows an example of a processing apparatus 300 for forming a processed portion 50 on the surface of a glass plate 10. The processing apparatus 300 may include a laser beam emitting device 310 and a scanning device 320. The scanning device 320 may be a galvanometer scanner, a polygon scanner, or the like. The scanning device 320 allows the direction of the laser beam LB emitted from the laser beam emitting device 310 to be arbitrarily changed in three dimensions. Therefore, the laser beam LB can be irradiated not only perpendicularly but also obliquely onto the surface of the glass plate 10. That is, the laser beam LB can be irradiated so that the optical axis of the laser beam LB forms an arbitrary angle with respect to the normal direction of the glass plate 10. Furthermore, even for a curved glass plate 10, for example, the laser beam LB can be irradiated at a desired position on the surface of the glass plate 10 at a desired angle. Furthermore, the laser beam LB is irradiated so that the energy intensity distribution on the surface of the glass plate 10 provided by the irradiation of the laser beam LB to form one processed portion 50 has a non-axisymmetric shape (described in detail below).

[0025] Examples of light sources for the laser light irradiation device 310 include near-infrared lasers such as Yb fiber lasers (wavelengths: 1000 nm to 1100 nm), Yb disk lasers (wavelengths: 1000 nm to 1100 nm), Nd:YAG lasers (wavelengths: 1064 nm), and high-power semiconductor lasers (wavelengths: 808 nm to 980 nm). The laser light source may also be a UV laser (wavelengths: 310 nm to 360 nm), a green laser (wavelengths: 510 nm to 540 nm), a Ho:YAG laser (wavelengths: 2080 nm), an Er:YAG laser (2940 nm), or a laser using a mid-infrared optical parametric oscillator (wavelengths: 2600 nm to 3450 nm). A diode-pumped solid-state (DPSS) laser combined with a wavelength conversion element may also be used.

[0026] The oscillation method of the laser beam LB may be a pulse oscillation method or a continuous oscillation method, but the pulse oscillation method is preferable from the viewpoints that it can reduce unintended damage to the vicinity of the irradiated portion and can irradiate with high power, thereby shortening the irradiation time.

[0027] The wavelength of the laser beam LB is preferably a wavelength that allows it to be at least partially transmitted through the glass plate 10. Specifically, the wavelength of the laser beam LB may be 250 nm or more and 5,000 nm or less, and preferably 310 nm or more and 3,000 nm or less. Laser beams with wavelengths in this range bring the absorption coefficient of the glass plate 10 into an appropriate range, making it possible to form a processed portion 50 that provides appropriate breakability and good external visibility.

[0028] Figure 4 shows a plan view of an automotive window glass 1 having a plurality of processed portions 50 formed on the surface of the glass plate 10, specifically, on the surface facing the interior of the vehicle. As shown in Figure 4, a plurality of processed portions 50 are formed at intervals on the surface of the glass plate 10. The processed portions 50 are formed over the entire glass plate 10, preferably over the see-through region 5. By forming the processed portions 50 at intervals in this manner, it is possible to avoid obstructing the occupant's view when they look outside the vehicle (exterior of the vehicle) through the automotive window glass 1 (ensuring external visibility). Furthermore, it is possible to ensure that the entire automotive window glass 1 is breakable in the event of a collision.

[0029] In the example shown in Figure 4, the processed portion 50 on the automotive window glass 1 is formed in a staggered pattern when viewed in a plane, but the pattern of the processed portion 50 in the surface direction is not limited to a staggered pattern and may be, for example, a lattice pattern.

[0030] The formation of the processed portions 50 by irradiation with laser light LB is preferably performed with a pitch P (FIG. 4) of 1 mm to 200 mm, more preferably 10 mm to 100 mm, and even more preferably 20 mm to 80 mm. The pitch P is the distance between the center position of one processed portion 50 and the center position of another processed portion 50 located adjacent to that processed portion 50. The center position of the processed portion 50 may be the center position of the diameter D (diameter of the circumscribed circle of the processed portion 50) of the processed portion 50 described below. The pitch P may be uniform throughout or may vary depending on the location. In the latter case, the pitch of the processed portions 50 in this specification is an average value. By setting the pitch P of the processed portions 50 to 1 mm or more, it is possible to prevent the processed portions 50 from being too close to each other, causing the compressive stress generated on the surface to be continuously distributed in the plane direction, which actually makes the glass plate less likely to break. By setting the pitch P of the processed portions 50 to 200 mm or less, the processed portions 50 which are the starting points for cracks are distributed at appropriate intervals, and when an impact is applied to the automotive window glass 1 from outside the vehicle, the automotive window glass 1 is more likely to break appropriately.

[0031] When the automotive window glass 1 is a laminated glass, the processed portion 50 is preferably formed on one or more surfaces of the first glass sheet 11 and the second glass sheet 12 ( FIG. 2 ). In particular, the processed portion 50 is preferably formed on the interior surface (second surface F2) of the first glass sheet 11 and / or the interior surface (fourth surface F4) of the second glass sheet 12, which are likely to crack first when subjected to an impact from outside the vehicle. This makes it easier for cracks to initiate in the automotive window glass 1 when a vehicle collides with a pedestrian, thereby effectively reducing the impact on the pedestrian and protecting the pedestrian. From the perspective of promoting such appropriate crack initiation, the processed portion 50 is preferably formed on the interior surface (fourth surface F4) of the second glass sheet 12, which is more likely to crack when subjected to an impact from outside the vehicle. Furthermore, it is preferable that the processed portion 50 is formed on both the interior side surface (second surface F2) of the first glass plate 11 and the interior side surface (fourth surface F4) of the second glass plate 12, since this allows the strength of the entire automotive window glass 1 to be moderately reduced.

[0032] In the laminated glass for automobile windows, the processed portion 50 formed on the first glass plate 11 and the processed portion 50 formed on the second glass plate 12 may or may not overlap in a planar view. If the processed portion 50 on the first glass plate 11 and the processed portion 50 on the second glass plate 12 overlap in a planar view, this is preferable because it makes it easier for cracks to propagate in the thickness direction when the automobile window glass 1 hits a person 200.

[0033] FIG. 5a shows an enlarged view of portion I in FIG. 4, including one processed portion 50. FIG. 5b shows a cross-sectional view taken along line II-II in FIG. 5a, and FIG. 5c shows a cross-sectional view taken along line III-III in FIG. 5a. The shape of the processed portion 50 shown in FIGS. 5a to 5c is a schematic view for ease of explanation. As shown in FIGS. 5a to 5c, the processed portion 50 includes a crack 56 that reaches the surface of the glass plate 10. In addition to the crack 56, the processed portion 50 may also include a recess 55 formed in the center of the processed portion 50 in a planar view. In other words, the processed portion 50 may include a recess 55 and a crack 56 formed around the recess 55. However, the processed portion 50 formed according to this embodiment may not include the recess 55.

[0034] The number of cracks 56 in one processed portion 50 may be one or more. The shape, formation position, etc. of the cracks 56 are not particularly limited. The cracks 56 may be formed away from the recessed portion 55 as shown in Figure 5a, or may be formed in contact with the recessed portion 55 and extending from the recessed portion 55.

[0035] Furthermore, it is preferable that the shape of the crack 56, in plan view, is an arc shape that follows the circumferential direction of the recess 55. Furthermore, when the processed portion 50 is divided into two by any straight line that passes through the center of the processed portion 50, in plan view, it is preferable that the crack 56 is included on each of the two sides.

[0036] Cracks 56 that reach the surface of the glass plate 10 are likely to become the starting point for cracks in the glass plate 10 when subjected to an external impact. Therefore, by ensuring that each processed portion 50 includes cracks 56, the strength of the automotive window glass can be appropriately reduced, making it appropriately more likely to break in the event of a collision.

[0037] The crack 56 is formed when a specific area on the surface of the glass plate 10 irradiated with the laser light LB is heated, and in some cases a recess 55 is formed by ablation, and then the glass plate is rapidly cooled, causing tensile stress to occur around the specific area.

[0038] However, depending on the conditions, a crack origin may not be generated, and the processed portion may not contain a crack. In the case of a collision between a vehicle and a person, as shown in FIG. 2 , a crack 56 reaching the surface of the glass sheet 10 is the primary starting point for cracking (fracture) of the glass sheet 10. Therefore, if the proportion of processed portions without cracks increases, the automotive window glass 1 may not properly break during a collision between a vehicle and a person. The reason why cracks may not form in the processed portion 50 is thought to be that the energy intensity distribution on the surface of the glass sheet 10 imparted by the irradiation of the laser beam LB to form one processed portion 50 has an axially symmetric shape with the optical axis as the central axis, so the irradiated area is heated axially symmetrically around the optical axis, resulting in uniform tensile stress around the periphery. Alternatively, a laser beam with higher energy may be irradiated to more reliably form the crack. However, in this case, the length or extension of the crack may increase, making the processed portion larger and more noticeable, potentially reducing external visibility.

[0039] Therefore, in this embodiment, the laser beam LB is irradiated so that the energy intensity distribution on the surface of the glass plate 10 imparted by the irradiation of the laser beam LB to form one processed portion 50 has a non-axisymmetric shape. This disrupts the uniformity of tensile stress generated around the area irradiated with the laser beam, making it easier for crack initiation points to be generated. Therefore, by irradiating the laser beam, a processed portion 50 including a crack 56 reaching the surface of the glass plate 10 can be formed with high reproducibility. This allows, for example, a high ratio of the number of processed portions 50 including cracks 56 to the total number of multiple processed portions 50 formed on the surface of the glass plate 10. This ratio may be preferably 95% or more, more preferably 98% or more, and even more preferably approximately 100%.

[0040] In this specification, the term "axially symmetric" refers to the energy intensity distribution being such that the energy intensity varies only depending on the distance from the central axis, with the axis passing through the position where the energy intensity distribution is at its maximum. When laser light is irradiated at a fixed point along the normal direction of the surface of a glass plate in a conventional manner, the energy intensity distribution on the surface of the glass plate imparted by the laser light LB has an axially symmetric shape with the optical axis as the central axis, such as a Gaussian distribution or a distribution that can be approximated to a Gaussian distribution. Therefore, the term "non-axially symmetric" refers to a shape that is not axially symmetric as described above. In other words, the energy intensity distribution imparted to form one processed portion 50 has a shape that is not axially symmetric with the axis passing through the position of the maximum value in the distribution as the central axis. For example, in a region irradiated with laser light to form one processed portion 50, the energy intensities at two different positions at the same distance from the position where the applied energy is at its maximum may differ from each other.

[0041] A specific example of a non-axisymmetric energy intensity distribution on the surface of the glass plate 10 provided by irradiation with the laser beam LB to form one processed portion 50 is a method of moving the laser beam irradiation position along the surface of the glass plate 10 when forming one processed portion 50 (hereinafter, also referred to as sweep irradiation). Here, sweep irradiation will be described with reference to FIG. 6 . The circular region RS in FIG. 6 is the irradiation spot of the laser beam LB. In sweep irradiation, after one irradiation spot RS is formed, a next irradiation spot RS is formed shifted downstream in the sweep direction Ds (located at the top of FIG. 6 ). This process is repeated until multiple irradiation spots RS are overlapped. Therefore, the region irradiated with the laser beam LB to form one processed portion 50 is elongated rather than circular.

[0042] The intensity distribution of the energy of the laser beam applied to form one irradiation spot RS usually has an axially symmetric shape with the optical axis as the central axis. In contrast, the intensity distribution of the integrated energy required to form the irradiation area obtained by sweep irradiation has a non-axisymmetric shape. This disrupts the uniformity of the tensile stress generated when the processed portion 50 is cooled, making it easier for the start of the crack 56 to form. Furthermore, in sweep irradiation, the timing of the laser beam irradiation differs between the upstream side (lower side in FIG. 6 ) and the downstream side (upper side in FIG. 6 ) of the sweep direction Ds. This time difference causes the temperature of the surface of the glass plate 10 to become non-uniform along the sweep direction Ds. This temperature non-uniformity also makes it easier for the start of the crack 56 to form.

[0043] As described above, the laser beam LB may be irradiated in a pulsed or continuous wave manner, but in the case of sweep irradiation, it is preferable to use a pulsed laser, since the pulsed laser generates shock waves at the irradiation position, which are particularly advantageous for generating and extending cracks. In this case, the irradiation position of the laser beam can be moved in the sweep direction Ds so that one pulse shot corresponds to one region RS (FIG. 6).

[0044] In the case of pulsed irradiation, a short pulse laser, specifically a nanosecond pulse laser, a picosecond pulse laser, a femtosecond pulse laser, or the like, can be used. Among these, it is preferable to use a nanosecond pulse laser because high-power lasers are available at low cost. The specific pulse width may be preferably 0.001 ns or more and 500 ns or less, more preferably 1 ns or more and 100 ns or less. By setting the pulse width within the above range, multiphoton absorption is particularly good, and energy utilization efficiency can be improved. In addition, in the case of irradiation using pulsed irradiation, the pulse operation mode is not particularly limited, but a burst pulse mode is preferred because it allows for higher-power irradiation and shortens the irradiation time.

[0045] The sweep length in the sweep irradiation, i.e., the relative movement distance between the laser beam LB and the glass plate 10 to form one processed portion 50, may be preferably 10 μm or more and 1,000 μm or less, more preferably 20 μm or more and 1,000 μm or less, even more preferably 20 μm or more and 500 μm or less, and particularly preferably 20 μm or more and 100 μm or less. By setting the sweep length to 20 μm or more, the axial symmetry of the shape of the intensity distribution of the energy of the laser beam required to form one processed portion 50 can be reduced, improving the ease of generating crack initiation points. Furthermore, by setting the sweep length to 1,000 μm or less, it is possible to prevent the diameter (described below) or size of the obtained processed portion 50 from becoming excessively large, which would make the glass plate 10 excessively fragile and impair the robustness of the automotive window glass 1 and impair external visibility.

[0046] The sweep speed in the sweep irradiation, i.e., the relative movement speed between the laser beam LB and the glass plate 10, may be preferably 5 mm / s or more and 500 mm / s or less, more preferably 20 mm / s or more and 200 mm / s or less. By setting the sweep speed within the above range, an appropriate temperature distribution can be formed from the sweep start position to the sweep end position, and cracks 56 are more likely to be reliably formed in the processed portion 50.

[0047] Furthermore, when irradiating the laser beam LB using a pulsed oscillation method, the pulse energy may be preferably 1 μJ to 1000 μJ, more preferably 20 μJ to 200 μJ. The number of irradiation shots may be preferably 2 to 1000, more preferably 10 to 200. The repetition frequency may be preferably 1 kHz to 2000 kHz, more preferably 10 kHz to 100 kHz.

[0048] The sweep irradiation of the laser beam may be performed by moving the glass plate 10 and / or the laser beam LB so that the glass plate 10 and the laser beam LB can move relative to each other. To achieve this, the irradiation spot of the laser beam LB may be moved by the scanning device 320 (FIG. 3) in the laser processing apparatus 300, or the glass plate 10 may be moved by using a conveying device or the like, or both may be performed.

[0049] 6, the sweep direction Ds in the sweep irradiation is a direction extending linearly from the bottom to the top of the drawing. However, the sweep direction Ds does not necessarily have to be linear, and may be curved or bent along the way. Furthermore, to form one processed portion 50, sweep irradiation may be performed two or more times in the same direction to form two or more rows of overlapping irradiation regions.

[0050] Referring again to Figures 5a to 5c, the processed portion 50 obtained by the manufacturing method for automotive window glass according to this embodiment will be further described. As shown in Figures 5a to 5c, the processed portion 50 includes a recess 55 as well as a crack 56. The recess 55 may be formed by ablation of the material on the surface of the glass sheet 10 at the irradiation spot when laser light is irradiated. The presence of the recess 55 makes the presence of the processed portion 50 more easily recognized during inspection of the resulting product, facilitating determination of whether the processed portion 50 has been reliably formed. Furthermore, during the bending process for curving the glass sheet, stress attempting to close the crack 56 may escape into the recess 55, thereby preventing the crack 56 formed around the recess 55 from closing.

[0051] The planar shape of the recess 55 may be elongated, i.e., have a major axis and a minor axis, or may have a major axis and a minor axis, as shown in Fig. 5a. Specifically, as shown in Fig. 5a, the recess 55 may be elliptical. When performing the above-described sweep irradiation, the recess 55 may have a shape having a major axis along the sweep direction Ds.

[0052] As shown in FIG. 5a, the diameter d of the recess 55 may be the diameter of a circumscribing circle of the recess 55 in a plan view. The diameter d of the recess 55 may be preferably 10 μm or more and 200 μm or less, more preferably 20 μm or more and 100 μm or less. When the diameter d of the recess 55 is 10 μm or more, the presence of the recess 55 is easily recognized during inspection, and it becomes easy to inspect whether or not the processed portion 50 is formed in the obtained product. Furthermore, when the diameter d of the recess 55, which occupies a large area of ​​the processed portion 50, is 200 μm or less, it is possible to prevent a decrease in external visibility when an occupant of the automobile 100 looks outside through the laminated glass 1.

[0053] In a plan view, the diameter D of the processed portion 50 may be the diameter of a circumscribed circle that includes the recess 55 and the crack 56, i.e., the diameter of the smallest circle that can accommodate the recess 55 and the surrounding crack 56. The diameter D of the processed portion 50 may preferably be 20 μm or more and 200 μm or less, more preferably 30 μm or more and 150 μm or less. A diameter D of 20 μm or more reduces the possibility of the crack 56 closing during the bending process of the glass sheet, making it easier to detect the formation of the processed portion 50 when inspecting the resulting product. Furthermore, a diameter D of 200 μm or less makes the processed portion 50 less noticeable to the eye of the occupant, suppressing obstruction to the occupant's view, i.e., improving the external visibility of the automobile window. Furthermore, the robustness of the automobile window glass 1 installed in an opening in the vehicle body 2 is also easily ensured. The upper limit of the diameter D, 200 μm, is smaller than the size of black spots (500 μm) permitted by the Japanese Automotive Standards Organization (JASO).

[0054] The ratio (D / d) of the diameter D of the processed portion 50 to the diameter d of the recess 55 may be preferably 1.2 or more and 4 or less, more preferably 1.2 or more and 3 or less. When the value of (D / d) is 1.2 or more, the crack 56 extends over a certain range, making it easier for the crack 56 to form a starting point for cracking in the glass plate 10 during a collision between a vehicle and a person. Furthermore, when the value of (D / d) is 4 or less, it is possible to prevent the extension range of the crack 56 from becoming excessively large, thereby preventing external visibility from being impaired.

[0055] The length of the crack 56 may be preferably 10 μm or more and 500 μm or less, more preferably 20 μm or more and 150 μm or less. The length of the crack 56 may be the length of the center line of the crack 56 measured along the crack 56 in a plan view. When the length of the crack 56 is 10 μm or more, a starting point for cracking of the glass plate 10 is more likely to be formed in the event of a collision between a vehicle and a person. Furthermore, when the length of the crack 56 is 200 μm or less, the crack 56 can be prevented from being too noticeable and impairing external visibility.

[0056] The dimensions of the processed portion 50 in a plan view can be measured based on an image obtained by a digital microscope or the like from the side where the processed portion 50 is provided. The depth L of the recess 55 and the like can be measured using a laser microscope or the like.

[0057] As shown in Figures 5(b) and (c), the recess 55 has a predetermined depth L from the surface of the glass sheet 10. The depth L of the recess 55 is the distance from the surface of the glass sheet 10 to the deepest position of the recess 55. The depth L of the recess 55 may be preferably more than 0 µm and not more than 100 µm, more preferably 1 µm or more and not more than 50 µm. When the depth L is more than 0 µm, the above-mentioned effect of preventing the crack 56 from closing during bending is improved. Furthermore, when the depth L is 100 µm or less, a decrease in external visibility is prevented and the robustness of the automotive window glass 1 can be ensured.

[0058] The ratio (L / d) of the depth L of the recess 55 to the diameter d may preferably be greater than 0 and equal to or less than 0.5.

[0059] 5(b) and 5(c), the cross-sectional shape of the recess 55 taken in the thickness direction of the glass plate 10 is a partial ellipse, but the cross-sectional shape of the recess 55 may be rectangular or a partial rectangle, and a bottom surface may be formed. However, it is preferable that the outline of the cross-sectional shape of the recess 55 has a shape in which the tangent line changes continuously (a curved shape without sharp corners) except for the intersection position with the surface of the glass plate 10, because this can prevent strong scattering of light at the corner positions.

[0060] In the above, sweep irradiation has been mainly described as a specific example of a method for irradiating the surface of the glass plate 10 with laser light so that the energy intensity distribution on the surface of the glass plate 10 provided by the laser light irradiation for forming one processed portion 50 has a non-axisymmetric shape. However, methods other than sweep irradiation are also possible. For example, laser light can be irradiated so that the planar shape of the laser light irradiation spot is noncircular. Specifically, irradiation is performed so that the planar shape of the laser light irradiation spot is elongated, i.e., a shape having a major axis and a minor axis or a shape having a major axis and a minor axis. This allows the axial symmetry of the energy intensity distribution of the laser light to be broken by irradiating a fixed point without sweep irradiation. Therefore, during rapid cooling after laser light irradiation, the tensile stress generated around the irradiated area can be made non-uniform, making it easier for the initiation point of the crack 56 to form. In this specific example, the planar shape of the laser light irradiation spot may preferably be elliptical.

[0061] In order to irradiate the laser beam so that the planar shape of the irradiation spot of the laser beam has a major axis and a minor axis, the laser beam can be irradiated obliquely rather than perpendicularly to the surface of the glass plate 10. That is, the laser beam is irradiated so that the optical axis of the laser beam forms an angle with respect to the normal direction to the surface of the glass plate 10. Such adjustment of the irradiation angle of the laser beam can be easily performed by the scanning device 320 ( FIG. 3 ) in the laser processing device 300.

[0062] 7A and 7B are schematic diagrams showing a processed portion 50 formed by irradiating laser light LB so that the shape of the irradiation spot in a plan view is non-circular. Fig. 7A shows a plan view of the processed portion 50, and Fig. 7B shows a cross-sectional view taken along line IV-IV in Fig. 7A. As shown in Fig. 7A, the processed portion 50 includes a recess 55 and a crack 56 formed around the recess 55. The recess 55 has an elliptical shape in a plan view.

[0063] In Figure 7(b), the direction of the laser beam LB irradiated to form the processed portion 50 in this example is indicated by a thick arrow. The laser beam LB is irradiated so that the optical axis Ax of the laser beam LB forms an angle θ with respect to the normal direction N of the surface of the glass plate 10. The angle θ may be preferably 0° or more and 50° or less, more preferably 5° or more and 30° or less. By setting the angle θ to 5° or more, the tensile stress generated around the irradiated region during rapid cooling after laser beam irradiation can be made non-uniform, thereby improving the effect of facilitating the formation of the starting point of the crack 56. Furthermore, by setting the angle θ to 30° or less, the planar view shape of the formed recess 55 can be prevented from being excessively long, which would reduce external visibility, and further, a decrease in processing efficiency due to an increase in the reflectivity of the surface of the glass plate 10 can be prevented.

[0064] In this example, as shown in FIG. 7( b), the cross-sectional shape of the recess 55 is not bilaterally symmetric. In other words, the deepest point of the bottom of the recess 55 is offset from the center of the elliptical shape in a plan view. In this way, in this example, the three-dimensional shape of the recess 55 is also non-axisymmetric, which makes the tensile stress generated around the irradiated area non-uniform and promotes the formation of the starting point of the crack 56. Furthermore, in the example shown in FIG. 7( b), the deepest point of the bottom of the recess 55 passes through the optical axis Ax of the laser beam during laser beam irradiation, but may be offset from the optical axis Ax depending on the degree of refraction of the laser beam on the surface of the glass plate 10.

[0065] When forming multiple processed portions 50 in one glass plate 10, the laser light may be irradiated so that the angle θ varies depending on the processed portion 50. This allows the three-dimensional shape of the recesses 55 in the processed portion 50 to vary depending on the location. Therefore, the directions in which light is refracted and scattered can be mixed within the surface of the glass plate 10, and the possibility of multiple recesses 55 being visible to an occupant at the same time can be avoided.

[0066] Specific examples of the energy intensity distribution on the surface of the glass plate 10 imparted by irradiation with the laser beam LB to form one processed portion 50 having a non-axisymmetric shape are not limited to those described above. For example, as another specific example, two or more laser beams may be simultaneously irradiated in a shifted manner in the in-plane direction of the glass plate 10 to form one processed portion 50. In this case, two or more laser beam irradiation devices 310 may be prepared, and laser beams may be simultaneously irradiated from each laser beam irradiation device onto the region on the surface of the glass plate 10 where the processed portion 50 is to be formed. Alternatively, the laser beam emitted from the laser light source may be split into multiple beams using a diffractive optical element (DOE) or the like, and the irradiation spots of each beam may be shifted and irradiated onto the region on the surface of the glass plate 10 where the processed portion 50 is to be formed.

[0067] When the glass sheet 10 is float glass, the processed portion 50 is preferably formed on one of the two main surfaces of the glass sheet 10 that was in contact with molten metal, such as molten tin or a molten tin alloy, during manufacturing (hereinafter referred to as the bottom surface). The bottom surface, which was in contact with molten tin during the float process, contains tin near the surface. On the other hand, the top surface, which is the main surface opposite the bottom surface and was not in contact with molten tin, contains almost no tin. Here, on the top surface, which contains almost no tin, an ion exchange reaction between sodium ions in the glass and hydrogen ions in the outside air proceeds, gradually forming a low-hardness surface hydration layer. As a result, the top surface becomes less brittle over time and is less susceptible to cracking. In contrast, on the bottom surface, which contains tin, the ion exchange reaction between hydrogen ions and sodium ions is inhibited by the effect of tin, which is an asymmetric ion, and therefore the formation of a low-hardness surface hydration layer is less likely to proceed. Therefore, by forming the processed portion 50 on the bottom surface, cracks 56 can be more reliably formed in the processed portion 50. Furthermore, the breaking strength of the glass plate 10 is less likely to change over time, and its function of protecting people is maintained for a long period of time. Furthermore, the bottom surface, which contains a large amount of metal such as tin, significantly improves light absorption, especially in the UV region. This also has the advantage that the processed portion 50 can be processed with lower-energy laser irradiation.

[0068] The bottom surface, which contains a large amount of tin, and the top surface, which contains almost no tin, can be distinguished by measuring the tin concentration on both surfaces using, for example, a tin surface measuring instrument, TinCheck, manufactured by Bohle Corp. Furthermore, on the bottom surface, a tin-containing layer having a thickness of 5 μm to 15 μm can be detected by quantitatively measuring the tin concentration using a fluorescent X-ray method or an EPMA method.

[0069] When the automotive window glass 1 is laminated glass, the manufacturing method according to this embodiment further includes the following steps (a) to (c): (a) A first glass sheet 11 and a second glass sheet 12 are superimposed with an interlayer film 30 interposed therebetween to produce a laminate. (b) The laminate is placed inside a container such as a rubber bag, and then the container is heated while reducing the pressure inside, and the first glass sheet 11 and the second glass sheet 12 are bonded together with the interlayer film 30. The pressure inside the container is, for example, −100 kPa to −65 kPa, based on atmospheric pressure. The heating temperature of the container is, for example, 70°C to 110°C. (c) The laminate removed from the container is heated at 100°C to 150°C and compressed at a pressure of 0.6 MPa to 1.3 MPa. An autoclave, for example, is used for the compression bonding. Note that the manufacturing method of the laminated glass 1 may be a general method, and does not necessarily include the above step (c).

[0070] The first glass sheet 11 and the second glass sheet 12 are bent before the above step (a). The bending is performed after the glass sheets have been softened by heating. The heating temperature of the glass sheets during bending is, for example, 550°C to 700°C. The first glass sheet 11 and the second glass sheet 12 may be bent separately, or may be bent simultaneously after being stacked. The bending may be performed by gravity forming or press forming, or may include both.

[0071] In the method for manufacturing laminated glass for automobile windows, the step of forming the processed portion 50 by irradiating the surface of the glass sheet 10 with laser light can be performed at a stage before the glass sheets 10 are laminated (before the above-mentioned step (a)). That is, the processed portion 50 may be formed on the interior surface of the first glass sheet 11 and / or the second glass sheet 12, and then a laminate may be constructed via the interlayer film 30. Alternatively, if the processed portion 50 is formed only on the interior surface of the second glass sheet 12 on the interior side of the vehicle, the first glass sheet 11 and the second glass sheet 12 may be laminated via the interlayer film 30, and then the laser light LB may be irradiated from the interior side of the laminated glass. Furthermore, the step of forming the processed portion 50 may be performed before or after the bending step, which is performed before step (a).

[0072] The configuration of the processed portion 50 will be described in further detail with reference to Figure 8. Figure 8(a) is a modified example of the processed portion 50 shown in Figure 5(a). Figure 8(b) is a cross-sectional view taken along line V-V in Figure 8(a). As shown in Figures 8(a) and (b), the processed portion 50 may have a raised portion 57 along the periphery of the recess 55. The raised portion 57 is a portion raised from the surface of the glass plate 10, and may be formed by melting or softening the periphery of the recess 55 and then solidifying again when the recess 55 is formed by irradiation with laser light.

[0073] The raised portion 57 may be formed along the entire periphery of the recess 55 or along a portion of the periphery. That is, the periphery of the recess 55 may include portions where the raised portion 57 is formed and portions where it is not formed. Furthermore, the width of the raised portion 57 in a plan view may be non-uniform along the periphery. For example, as shown in FIG. 8( a), the raised portion 57 may have a maximum width Wmax and a minimum width Wmin. In this way, if the raised portion 57 is formed along a portion of the periphery of the recess 55 or the width of the raised portion 57 in a plan view is non-uniform along the circumferential direction, when the surface of the glass plate 10 is rapidly cooled after the recess 55 and the raised portion 57 around the recess 55 are formed by irradiation with laser light, the balance of tensile stresses generated around the recess 55 is disrupted, and cracks 56 are more likely to form.

[0074] The maximum width Wmax of the raised portion 57 in plan view may be 2 μm or more and 50 μm or less, and the minimum width Wmin may be 0.2 μm or more and 20 μm or less. The ratio of the minimum width Wmin to the maximum width Wmax (Wmin / Wmax) may be 0.001 or more.

[0075] Furthermore, the height h of the raised portion 57 may preferably be 0.1 μm or more and 10 μm or less. The ratio (h / L) of the height h of the raised portion 57 to the depth L of the recess 55 may be 0.001 or more and 0.1 or less. By setting (h / L) within the above range, it becomes easier to check the recess 55, and therefore the processed portion 50, during inspection, and a decrease in external visibility can be prevented.

[0076] When the distribution of strength (fracture stress) of the surface of the automotive window glass 1 obtained by this embodiment on which the processed portion 50 is formed is determined, the maximum value may be preferably 350 MPa or less, more preferably 250 MPa or less. The minimum value may be preferably 60 MPa or more, more preferably 80 MPa or more. When the automotive window glass 1 is a laminated glass, the distribution of strength of the interior surface of the glass plate 10 included in the laminated glass on which the processed portion 50 is formed (the second surface F2 of the first glass plate 11 and / or the fourth surface F4 of the second glass plate 12) may also be determined. The maximum value may be preferably 350 MPa or less, more preferably 250 MPa or less. The minimum value may be preferably 60 MPa or more, more preferably 80 MPa or more. Having the maximum value of 350 MPa or less makes the laminated glass more likely to break during a collision, thereby improving the effect of reducing impact to people. Having the minimum value of 60 MPa or more can suppress breakage of the laminated glass due to flying stones.

[0077] The experimental data will be explained below. In the following experimental data, Examples 1 to 3 are working examples, and Examples 4 to 6 are comparative examples.

[0078] <Preparation of Glass Samples> (Example 1) A glass sample (100 mm x 100 mm x 2 mm thick) was cut out from a glass plate of soda lime silicate glass composition obtained by the float method similar to a normal mass production process. A laser was irradiated from the bottom surface side of the glass sample to form a processed portion at one location in the center of the surface of the glass sample. For the laser irradiation, a processing device combining a laser beam irradiation device (LD-excited solid-state laser) and a galvanometer scanner as a scanning device was used. The laser beam irradiation device used a pulsed laser oscillation method (pulse width: 10 ns), and the wavelength of the laser beam was 355 nm. In addition, the spot diameter of the laser beam on the surface of the glass sample was 1 / e ２ The aperture ratio and working distance of the lens were set to a diameter of 32 μm. During laser irradiation, the laser beam irradiation spot on the glass sample surface was moved by linearly moving the laser beam irradiation device using a scanning device. Other conditions related to laser irradiation are shown in Table 1.

[0079] The obtained sample after laser irradiation was placed in an electric heating furnace and subjected to a heat treatment at 658° C. for 200 seconds, which is the same heat treatment as in a normal bending process, to obtain a sample of Example 1.

[0080] Examples 2 and 3 Samples were obtained in the same manner as in Example 1, except that the laser light irradiation conditions were changed to those shown in Table 1.

[0081] FIG. 9 shows an image of one processed portion of the glass sample of Example 1 as a representative example.

[0082] (Examples 4 to 6) Samples were obtained in the same manner as in Example 1, except that the laser light irradiation conditions were changed to those shown in Table 1. In Examples 4 to 6, the laser light irradiation spot was not moved. That is, fixed-point irradiation was used, so there is no data on the sweep length and sweep speed.

[0083] <Observation and Measurement of Processed Portion> The processed portion formed on the glass sample was observed from the bottom surface side using a digital microscope VHX-6000 manufactured by Keyence Corporation. For each example, 10 glass samples were prepared, and the number of samples in which crack formation was observed was counted, and the percentage was calculated to represent the probability of crack formation (%). In addition, based on the image observed from the bottom surface side, the diameter D of the circumscribing circle of the processed portion and the diameter d of the circumscribing circle of the recess were calculated in a plan view.

[0084] <Measurement of Strength (Fracture Stress)> For each example, 10 glass samples were prepared, and the strength of each sample was measured as fracture stress (MPa). The fracture stress was measured according to ISO 1288-5 (2016) using R30. Specifically, a support ring with a diameter of 60 mm and a load ring with a diameter of 12 mm were used, and a load was applied by the load ring at a load rate of 0.3 mm per minute to measure the fracture load. The load ring was placed on the top surface side of the glass plate, and the load was applied from the top surface side. Furthermore, the fracture stress was calculated using the formula described in ISO 1288-5 (2016). From the obtained data, the maximum and minimum values ​​were recorded, and the average value was calculated and recorded.

[0085] <Evaluation of External Visibility> Samples for evaluating external visibility corresponding to each example were prepared as follows. Glass samples (300 mm x 300 mm x 2 mm thick) were cut out from a glass plate having a soda-lime silicate glass composition obtained by the float process, and laser irradiation was performed on the bottom surface side of the glass sample. The laser light irradiation conditions were as shown in Table 1, and the laser was irradiated intermittently at 81 locations scattered in a square lattice pattern with a 30 mm pitch within the surface of the glass sample. After laser irradiation, the glass sample was placed in an electric heating furnace and subjected to heat treatment at 658°C for 200 seconds, which was equivalent to a heat treatment performed in a commonly performed bending process.

[0086] Furthermore, two of the above heat-treated glass samples were laminated together with their bottom surfaces facing upwards through an interlayer film (PVB resin), and then pressed together to form a laminated glass. This resulted in a laminated glass sample in which a 2 mm thick glass sample, a 0.76 mm thick interlayer film, and a 2 mm thick glass sample were laminated.

[0087] The obtained laminated glass sample was placed at a distance of 400 mm from the evaluator, with the interior side of the glass sample facing the face of the evaluator, and the evaluator looked at an image on the opposite side of the laminated glass sample (the exterior side of the vehicle) under natural light and evaluated the visibility of the image. The evaluation criteria were as follows: ⊚: No bright spots were visible at all; ◯: Some bright spots were visible in some places; Δ: Periodic bright spots were weakly visible overall; ×: Periodic bright spots were strongly visible overall.

[0088]

[0089] As shown in Table 1, in Examples 1 to 3, in which the laser irradiation was performed by moving the irradiation spot so that the energy intensity distribution on the surface of the glass sample imparted by the laser light irradiation to form one processed portion had a non-axisymmetric shape, it was found that the probability of crack formation was high, cracks were more reliably formed in the processed portion, and the maximum value of fracture stress was sufficiently low, making it possible to provide a glass plate that could be broken appropriately. It was also found that when laminated glass was produced under the laser light irradiation conditions of Examples 1 to 3, high external visibility was obtained.

[0090] The disclosure of Japanese Patent Application No. 2024-091320 is incorporated herein by reference in its entirety.

[0091] All publications, patent applications, and technical standards mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent application, or technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for manufacturing automotive window glass, comprising irradiating the surface of a glass sheet with laser light to form a plurality of processed portions at intervals, each containing a crack that reaches the surface of the glass sheet, wherein the energy intensity distribution on the surface of the glass sheet imparted by the laser light irradiation to form one of the processed portions has a non-axisymmetric shape.

2. The method for manufacturing automotive window glass according to claim 1, wherein a plurality of the processed portions are formed at a pitch of 10 mm or more and 200 mm or less.

3. A method for manufacturing automotive window glass according to claim 1 or 2, wherein, in irradiating the laser light, the irradiation position of the laser light on the surface of the glass plate is moved relatively along the surface of the glass plate, and the moving distance for forming one processed portion is 20 μm or more and 1,000 μm or less.

4. The method for manufacturing automotive window glass according to claim 1 or 2, wherein the laser light is irradiated in a pulsed oscillation manner.

5. A method for manufacturing an automotive window glass according to claim 1 or 2, wherein the length of the crack in plan view is 10 μm or more and 500 μm or less.

6. A method for manufacturing automotive window glass as set forth in claim 1 or 2, wherein the processed portion includes a recess and the crack formed around the recess, and the diameter of the recess is 10 μm or more and 200 μm or less.

7. The method for manufacturing an automotive window glass according to claim 6, wherein the shape of the recess in plan view has a major axis and a minor axis.

8. A method for manufacturing automotive window glass according to claim 1 or 2, wherein the shape of the irradiation spot of the laser light in a plan view has a major axis and a minor axis.

9. A method for manufacturing an automobile window glass according to claim 8, wherein the laser light is irradiated so that the optical axis of the laser light forms an angle with respect to the normal direction of the surface of the glass plate.

10. A method for manufacturing laminated glass for automobile windows, the laminated glass for automobile windows comprising, from the exterior side to the interior side of the vehicle, a first glass sheet, an interlayer film, and a second glass sheet, in this order; and forming, at intervals, a plurality of processed portions including cracks reaching the surface of the first glass sheet and / or the second glass sheet by irradiating a laser beam onto the interior surface of the first glass sheet and / or the second glass sheet, wherein the energy intensity distribution on the surface of the first glass sheet and / or the second glass sheet imparted by the laser beam to form one processed portion has a non-axisymmetric shape.

11. An automobile window glass having a plurality of processed portions formed at intervals on the surface of a glass plate, the processed portions including recesses and cracks formed around the recesses and reaching the surface of the glass plate, and the shape of the recesses in a plan view has a major axis and a minor axis.

12. An automotive window glass as set forth in claim 11, wherein the processed portion includes a raised portion along the periphery of the recess, and the raised portion is formed on part of the periphery, or the width of the raised portion in a plan view is non-uniform along the circumferential direction.

13. A laminated glass for an automobile window comprising, from the exterior side to the interior side of the vehicle, a first glass sheet, an interlayer film, and a second glass sheet, in this order, and comprising the automobile window glass according to claim 11 or 12 as the first glass sheet and / or the second glass sheet.

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