Vehicle window with functionalized transmission region and transmitting and / or receiving arrangement for a vehicle, in particular a lidar arrangement
Patent Information
- Application Number
- PCT/EP2026/057286
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-04-15
- Filing Date
- 2026-03-16
- Publication Date
- 2026-10-22
Smart Images
Figure EP2026057286_22102026_PF_FP_ABST
Abstract
Description
[0001] SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0002] 1
[0003] Vehicle windscreen with functionalized transmission area and transmit and / or receive arrangement for a vehicle, in particular lidar arrangement. The invention relates to a vehicle windscreen with a functionalized transmission area, which is provided for the optical beam path of a transmitter and / or receiver of electromagnetic beams.
[0004] Providing simply functionalized glass products has long been a technical challenge, and various solutions have been proposed to impart anti-fog, anti-reflective, or anti-dirt properties to the glass. The most widespread solutions are anti-fog coatings, where an additional coating on a glass surface gives it hydrophobic or superhydrophobic properties; anti-reflective coatings, which minimize reflection due to selected coating materials with appropriate refractive indices; and dirt-repellent coatings, which provide the surface with both hydrophobic and oleophobic wetting properties. For example, US Patent 2022 / 388281 A1 discloses a laminated glass pane for vehicles that has an anti-reflective coating in the area of a through-hole for a LiDAR system.This disc serves to improve the transmission for the LIDAR system.
[0005] Although good results can be achieved with this method, such coatings can partially or completely lose their properties over a long period of use due to loss of adhesion, mechanical stress, or exposure to the elements. Anti-reflective coatings, for example, place high demands on the uniformity of the layer thickness. Unevenly coated lenses exhibit color gradients or even Newton's rings and are therefore unsuitable for many applications. Surfaces coated with anti-reflective coatings are also susceptible to contamination (fingerprints, cleaning agent residues) because these also constitute a thin layer and thus affect the optical properties. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0006] 2
[0007] Therefore, solutions were sought that would structure the glass surface itself in such a way that it would not exhibit water droplet formation, reflection, or dirt adhesion, even due to physical effects. This is generally achieved by introducing a structure into the glass surface with a height and spacing in the micrometer range. The dimensions of the structure vary depending on the desired functionality.
[0008] Etching the glass surface with hydrofluoric acid was proposed as a method for creating textures. However, this solution proved to be rather disadvantageous, as it resulted in a highly irregular and uneven texture, particularly in height and spacing, leading to a loss of transparency. Furthermore, the process steps are complex and costly in terms of handling, safety equipment, and disposal due to the use of highly problematic hydrofluoric acid.
[0009] Another approach to creating a structure, for example in a glass surface, by applying ultrafast, femtosecond laser pulses is described in US 2012 / 0328905 A1. Here, the surface is structured by targeted laser treatment in such a way that it exhibits both micrometer-scale structures and nanometer-scale substructures. The aim of the structuring described here is to change the color or the absorption capacity of the structured material.
[0010] A similar approach is pursued in the solution proposed in WO 2022 / 258998 A1 for structuring a glass surface with the aim of preventing fogging while maintaining transparency as much as possible. The process involves introducing nanostructures by applying a focused, polarized, and pulsed laser beam. The structuring is applied across the entire surface to be structured and is applied point by point by laser irradiation. This is associated with a high process effort, as, in addition to suitable laser calibration, the points must be addressed individually, preferably in overlap mode. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0011] 3
[0012] Therefore, this laser structuring is associated with a rather low processing speed.
[0013] A further development of this laser structuring method is described in WO 2023 / 280793 A2. A method and a device for laser interference structuring of substrates with periodic dot structures for antireflection properties are presented. The structured substrate comprises a periodic dot structure in the micrometer or submicrometer range, wherein the periodic dot structure is formed from inverted cones, and wherein the inverted cones are periodically arranged at a distance relative to their respective saddle point or center of height (circular base) in the range of 50 nm to 50 pm, preferably in the range of 50 nm to 20 pm, particularly preferably in the range of 100 nm to 4 pm, more preferably in the range of 100 nm to 2 pm, even more preferably in the range of 200 nm to 1.5 pm, and most preferably in the range of 300 nm to 800 nm, in order to generate the desired antireflection properties.Glass or a transparent polymer is described as a suitable material for a substrate.
[0014] However, the surfaces created in this way, like the coatings, exhibit a need for improved durability. Due to various phenomena, particularly organic adsorption on the structured surface, it has been shown that long-term durability decreases over time, indicating potential for improvement with regard to durable and / or weather-exposed products such as automotive parts. Furthermore, it is of particular interest to keep the transmission areas for the beam path of optical sensors, especially lidar sensors, free of optical interference.
[0015] There have recently been several efforts to address these disadvantages. For example, WO 2023 / 202817 A1 describes a process for manufacturing a glass pane with a reduced-reflection surface. In this process, a glass substrate is coated with a SiO2 layer, which is then structured using pulsed, circularly polarized laser radiation to create raised areas. (SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT)
[0016] 4
[0017] To achieve an antireflective effect, the document proposes applying a further, separate coating after laser structuring in order to give the disc additional functionality such as hydrophobic or hydrophilic properties. However, achieving a targeted antireflective effect through laser structuring is not only costly due to the extremely small structures required in the nanometer range, necessitated by the high-precision machines, but also very time-consuming.
[0018] WO 2024 / 047256 A1 describes a method for structuring substrates using laser interference to create periodic dot structures that primarily exhibit anti-fogging properties. The document also discloses that an additional coating can be applied to enhance and / or modify this property; however, this always relates to the creation or improvement of hydrophilic / superhydrophilic properties associated with the anti-fogging function. A fundamentally different functionality is neither disclosed nor proposed.
[0019] The object of the present invention is to provide a vehicle window with a functionalized transmission area, which is intended for the optical beam path of a transmitter and / or receiver of electromagnetic rays, whereby a multitude of optical disturbances are to be prevented.
[0020] At the same time, the durability of the protective functionalities incorporated into the transmission area should be improved. The manufacturing process should be easy to integrate into existing industrial processes for vehicle windscreens, and an excessive number of superimposed coatings with different functionalities should be avoided due to the complexity involved in coordinating the layer sequence.
[0021] These and other problems are solved according to the invention by a vehicle windscreen according to independent claim 1 and a method for manufacturing such a vehicle windscreen according to claim 11. Advantageous embodiments of the invention are set forth in the dependent claims. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0022] 5
[0023] The invention relates to a vehicle window with an exposed outer surface I, an inner surface II and a transmission area which is provided for the optical beam path of a transmitter and / or receiver of electromagnetic radiation, and with a viewing area which in particular comprises the field of view B or I according to ECE-R43, wherein the outer surface I and / or the inner surface II in the transmission area has a transparent coating and a laser structuring in the coated area, wherein the transparent coating is an anti-reflection coating and the laser structuring provides a second functionality which is different from the first anti-reflection functionality, wherein the laser structuring is selected from the group of anti-fog structuring and dirt-repellent structuring.
[0024] In other words, by using laser structuring in conjunction with a transparent coating, it has been possible to functionalize the treated surface in the transmission range, combining two different optical functional properties: anti-fog, anti-reflective, and dirt-repellent. Both of these combined properties are durable and long-lasting. It has been shown that the durability of the combined properties is significantly improved compared to glass panes treated with only the respective individual treatments, i.e., only laser structuring or only a transparent coating.
[0025] The invention relates in particular to the transmission area of a vehicle window for the beam path of sensors, which, in contrast to the viewing area of the window, is intended for the optical beam path of a transmitter and / or receiver of electromagnetic radiation. This refers to a locally limited area of the vehicle window that is designed and suitable for allowing an optical beam path of a transmitter and / or receiver of electromagnetic radiation to pass through the transmission area when such a transmitter and / or receiver is arranged on the interior side of the vehicle window and is directed towards the SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0026] 6
[0027] The transmission area is directed towards the interior surface of the vehicle window. The transmission area is typically identifiable on the vehicle window by the fact that it is surrounded by an opaque masking area and / or that a mounting device for the transmitter and / or receiver is attached to the vehicle window. The transmission area and the total area covered with the anti-reflective coating preferably correspond to at most 10% of the total area of the vehicle window, more preferably to at most 5%. According to the invention, the transmitter and / or receiver is arranged or provided for on the interior side of the vehicle window, such that its beam path passes through the vehicle window, more precisely through the transmission area of the vehicle window.
[0028] In a preferred embodiment of the vehicle windscreen according to the invention, the transparent coating and / or the laser structuring is not arranged in the viewing area of the vehicle windscreen. In this way, structuring and / or anti-reflective coatings can be provided, in particular, which are, for example, transparent to the wavelength of the sensor and / or receiver in the transmission range, but not sufficiently transparent and / or clear for the specific requirements of the viewing area of the vehicle windscreen.
[0029] The vehicle window is designed to separate the vehicle interior from the external environment within a vehicle window opening. It has two exposed surfaces: an outer surface, which, when installed, is exposed to the external environment, and an inner surface, which, when installed, is exposed to the vehicle interior.
[0030] The vehicle window can be designed as a single pane of glass, preferably as tempered safety glass, or as a laminated pane. The laminated pane comprises an outer pane and an inner pane bonded together via a thermoplastic interlayer. For the purposes of the invention, the inner pane is the pane of the laminated pane facing the vehicle interior. The outer pane is the pane facing the external environment.
[0031] 7
[0032] The outer pane and the inner pane each have an outer and an inner surface and a circumferential side edge running between them. For the purposes of the invention, the outer surface is the main surface intended to face the external environment when installed. For the purposes of the invention, the inner surface is the main surface intended to face the interior when installed. The inner surface of the outer pane and the outer surface of the inner pane face each other and the intermediate layer and are connected to each other by the thermoplastic intermediate layer.
[0033] In this basic structure of a composite window, the outer surface of the outer pane forms the exposed outer surface of the vehicle window, and the inner surface of the inner pane forms the exposed inner surface of the vehicle window. However, within the scope of the present invention, it is possible for the exposed inner surface in the transmission area to be formed by a different surface, in particular the surface of a support substrate attached to the inner pane or of an insert within a feedthrough through the inner pane.
[0034] The transmitter and / or receiver of the embodiment according to the invention is preferably arranged on the interior side of the vehicle window, i.e., it is located inside the vehicle, for example, attached to the vehicle window or otherwise secured within the vehicle interior. The transmitter and / or receiver is directed forward through the vehicle window (relative to the intended direction of travel when driving forward). The transmitter and / or receiver can therefore emit electromagnetic radiation forward through the vehicle window and / or detect electromagnetic radiation from a space in front of the vehicle through the vehicle window. The beam path of the transmitter and / or receiver passes through the vehicle window. The area of the vehicle window through which the beam path passes is referred to, for the purposes of the invention, as the transmission area.The transmission area runs between the exposed interior surface and the exposed exterior surface SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT.
[0035] 8
[0036] Surface of the vehicle window. The area of the exposed interior surface, which lies in the transmission area, is (in particular completely) provided with the transparent coating according to the invention and the laser structuring with different functionalizations.
[0037] The electromagnetic radiation emitted by the transmitter and / or detected by the receiver is preferably infrared radiation (IR radiation, radiation in the IR range) with a wavelength of 1540 nm to 1560 nm, particularly preferably from 1545 nm to 1555 nm, most preferably from 1548 nm to 1552 nm, and especially about 1550 nm.
[0038] In an advantageous embodiment, the transmitter and / or receiver is a lidar module, a light / rain sensor, or a camera. A lidar module comprises a transmitter of electromagnetic radiation and a receiver for radiation of the same wavelength. The electromagnetic radiation emitted by the transmitter, to which the receiver is sensitive, is referred to in the context of the invention as the operating radiation of the lidar module, and its wavelength as the operating wavelength. The operating wavelength of the lidar module is preferably from 1540 nm to 1560 nm, particularly preferably from 1545 nm to 1555 nm, and most preferably from 1548 nm to 1552 nm, and especially approximately 1550 nm.
[0039] In principle, all common lidar systems can be used, for example
[0040] • TOF lidar (time of flight), in which concentrated, pulsed radiation is emitted and the radiation reflected by an obstacle is returned to the receiver; the distance from the obstacle can be calculated based on the time that elapses between the emission of the radiation pulse and the detection of the reflected signal; here again, various variants are possible:
[0041] • “Scanning lidar”, in which several individual radiation pulses are emitted in different directions, for example by means of a rotating mirror; from which the overall image is obtained; SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0042] 9
[0043] • “Flash lidar”, in which a radiation pulse floods the entire area of space corresponding to the receiver’s field of view;
[0044] • FMCW lidar (frequency-modulated continuous wave), in which non-pulsed, continuous radiation is emitted, the frequency (i.e., wavelength) of which is modulated, and radiation reflected from an obstacle is returned to the receiver; the distance and speed of the obstacle can be calculated based on the frequency difference between the emitted and detected radiation.
[0045] The type of transmitter and receiver depends on the type of lidar system used. The transmitter is typically a laser, in particular a diode laser, which can be pulsed (especially TOF lidar) or continuous (especially FMCW lidar). The receiver can be, for example, a photodiode or a photodiode array, in particular an InGaAs photodiode, an avalanche photodiode (APD), in particular a single-photon avalanche photodiode (SPAD), or a photomultiplier, in particular a silicon photomultiplier (SiPM).
[0046] The vehicle windscreen according to the invention comprises a transparent anti-reflective coating in the transmission area.
[0047] Transparent anti-reflective coatings are generally known to those skilled in the art and are among the most common coatings used for glass, particularly in the field of vehicle windows. Within the scope of the invention, the term "anti-reflective coating" encompasses anti-reflective coatings for the visible spectrum, IR-reflective coatings, and / or low-E (low-emission) coatings. Each of these coatings serves to influence the reflection of emitted or incident electromagnetic waves and, in conjunction with the glass material of the pane, to achieve either a reduced or an increased reflection of these electromagnetic waves. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0048] 10
[0049] An antireflection coating according to the invention is preferably a thin-film coating, i.e., a stack or sequence of several thin layers. Optically high-refractive-index layers and optically low-refractive-index layers are arranged alternately. The optical properties (in this case, in particular the antireflective properties) are determined by optical interference effects. The antireflection coating is a type of interference filter, whereby a (wavelength-dependent) reduction in the reflectance at the coated surface is achieved through destructive interference of the reflected rays. The optical properties, in particular the wavelength range for which the antireflective effect is achieved, depend especially on the optical thickness of the individual layers, which in turn results from the refractive index and the layer thickness.The thin layers are, in particular, dielectric layers.
[0050] Antireflection in the visible and near-infrared range can be achieved using a variety of deposited compounds. Silicon dioxide, yttrium fluoride, and magnesium fluoride are three popular materials with low refractive indices. Titanium dioxide and silicon nitride are each widely used as high-refractive-index components. Consequently, numerous combinations of high- and low-refractive-index layers are known. The following antireflection coatings serve as some examples.
[0051] WO 2001 / 37006 A1 describes an antireflective coating with the layer sequence glass / Si3N4 / SiO2 / Si3N4 / SiO2, wherein the SiO2 layers contain 10% by weight of aluminum oxide. Aluminum-containing SisN4 and SiO2 layers for an antireflective coating are also known from FR 2 898295 A1, FR 2 841 894 A1, and for heat-insulating glazing from FR 2 889 182 A1.
[0052] Antireflective coatings with alternating silicon oxide-silicon nitride layers are also known from EP 2 149540 A1, JP 2004271480 A, and JP 2006-275526 A. FR 2 861 386 A1 describes in comparative example 3 a layer system with an aluminum-doped SiO2 layer on glass, a TiO2 layer deposited thereon, and a final aluminum-doped SisN4 layer. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0053] 11
[0054] The functional laser structurings mentioned within the scope of the present invention, namely anti-fog and dirt-repellent structures, are generally known to those skilled in the art and are among the common laser structurings of glass, particularly in the field of vehicle windows. They differ primarily in their morphology and the resulting wetting behavior, and the differences between the functional structurings can therefore be readily defined on this basis.
[0055] Laser structuring varies depending on its function. It can differ in its form as indentations and / or raised areas (for example, as a cone-shaped structure). However, the primary difference between laser structuring, depending on the desired function, lies in the dimensions of the depth and, in particular, the width and spacing of the indentations or raised areas.
[0056] A readily measurable parameter for categorizing laser structuring as anti-fog or dirt-repellent is the water contact angle. An anti-fog function aims to cause water to spread into a thin, transparent film and not form small, light-scattering droplets. This requires a correspondingly structured surface with a small water contact angle, so the behavior is also described as hydrophilic or superhydrophilic. A dirt-repellent function, on the other hand, aims to cause water and dirt to bead up and roll off. This requires a correspondingly differently structured surface with a large water contact angle, so the behavior is also described as hydrophobic or superhydrophobic.
[0057] The water contact angle (0), often also called the contact angle, is a quantitative measure of the wettability of a solid surface by water. It is determined by the thermodynamic equilibrium between the cohesive and adhesive forces at the three-phase contact line where the solid, liquid (water), and gaseous (ambient air) phases meet. The most widely used and preferred method for determining the static contact angle, especially on structured surfaces, is the sessile drop method. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0058] 12
[0059] Unlike methods that provide an average value over a large area (such as the Wilhelmy plate method), the sessile drop method measures the effective contact angle, which results from the interplay of material chemistry and surface morphology (described by models such as the Wenzel model or the Cassie-Baxter model for structured surfaces). Contact angle measurement is a non-destructive method for determining the wetting behavior of a solid, performed according to DIN EN ISO 19403-2. Modern contact angle measuring devices (goniometers) achieve accuracies of ±0.1°.
[0060] An anti-fog structure on a glass surface is generally known to those skilled in the art and comprises structures in a specific micrometer range. These micrometer-scale structures, either raised or recessed areas on the surface, alter the contact angle of water droplets on the structured surface in such a way that they prevent the formation of droplets on the surface during condensation of water vapor. These droplets would scatter light and thus make the affected areas of the glass pane almost or completely opaque.
[0061] In a preferred embodiment, laser structuring is an anti-fog structuring designed to prevent the formation of light-scattering water droplets by creating a surface with a water contact angle of <20°, preferably <10°.
[0062] In a preferred embodiment, the laser structuring is a dirt-repellent structuring designed to reduce dirt adhesion by creating a surface with a water contact angle of >90°, preferably >120°. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0063] 13
[0064] In a preferred embodiment of the invention, the laser structuring is an anti-fog structuring which has periodic structures in the surface I and / or II with a width of between 5 pm and 20 pm.
[0065] In a preferred embodiment of the invention, the depth of the structures present in surface I and / or II by laser structuring is <500 nm, preferably <120 nm. This depth measurement applies both to depressions directed into the volume of the glass pane and, alternatively, to protrusions measured downwards from their apex to the surface of the glass pane.
[0066] In various embodiments of the present invention, the transparent coating is an anti-reflective coating and the laser structuring is an anti-fog structuring, or the transparent coating is an anti-reflective coating and the laser structuring is a dirt-repellent structuring.
[0067] In other words, the possibility of combining transparent antireflection coating on the one hand and laser structuring on the other hand is not limited within the scope of the aforementioned respective functionalities, provided that different functionalities of the coating and the laser structuring are selected.
[0068] The invention further relates to a method for manufacturing a vehicle windscreen with an exposed outer surface I, an exposed inner surface II, and a transmission area intended for the optical beam path of a transmitter and / or receiver of electromagnetic radiation, and with a viewing area, which in particular comprises the field of view B or I according to ECE-R43, wherein the outer surface I and / or the inner surface II in the transmission area is first provided with a transparent anti-reflective coating, and a structure is introduced into the surface I and / or II thus coated by means of a laser, which SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0069] 14
[0070] selected from the group of anti-fog structuring and dirt-repellent structuring, or
[0071] wherein a structuring is first introduced into the outer surface I and / or the inner surface II in the transmission area using a laser, which is selected from the group of anti-fog structuring and dirt-repellent structuring, and the surface I and / or II thus structured is provided with a transparent anti-reflection coating.
[0072] The combination of special laser structuring and functionally distinct transparent coating produced by the inventive method imparts a different additional property to the anti-reflective effect of the coating resulting from the laser structuring. For example, it is possible to give an anti-reflective coating additional properties such as anti-fog or dirt-repellent properties. Furthermore, it has been shown that the durability of the combined anti-fog effect can be significantly improved compared to glass panes treated with only the respective individual treatments, i.e., only structured by laser or only provided with a transparent coating.
[0073] In a preferred embodiment of the method according to the invention, laser structuring is carried out by means of Direct Laser Writing (DLW), Direct Laser Interference Patterning (DLIP) or Laser-induced Periodic Surface Structuring (LIPSS).
[0074] According to the present invention, an anti-fog structure, an anti-reflective structure, or a dirt-repellent structure can be created, for example, using the DLIP (Direct Laser Interference Patterning) method. The laser structuring of the glass surface or the glass surface coated with a transparent coating then exhibits a repeating interference pattern. In physics, the term interference describes the superposition of two or more SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0075] 15
[0076] Waves according to the principle of superposition. This principle states that the amplitudes (not the intensities) of the waves are added together during their interaction. Interference occurs with all types of waves, regardless of whether they are sound waves, light waves, matter waves, or other types of physical waves. When waves cancel each other out, this is referred to as complete destructive interference. Conversely, when the amplitudes reinforce each other, this is called constructive interference. A pattern composed of areas of constructive and destructive interference is called an interference pattern within the scope of the present invention.This results in alternating characteristic interference minima and interference maxima, which, within the scope of the present invention, lead to depressions in the glass surface being arranged in a characteristic pattern. A widely used example of this is the striped pattern or the dot pattern.
[0077] In other words, the interference pattern consists of a plurality of depressions simultaneously generated by interference laser structuring. These depressions are uniformly spaced and are formed together on the surface within the laser's impact zone. The impact zone of the interfering laser radiation can be essentially circular or square, so that the repeating interference pattern represents a sequence of such shaped areas. The unstructured spacing between these interference pattern regions is chosen to maintain functionality. Preferred values for the size of the depressions formed by the laser interference, their individual spacing within the interference pattern, and / or the spacing of the repeating interference pattern regions have already been described above in connection with their functionality.
[0078] Direct Laser Interference Patterning is a holographic technique that utilizes the phenomenon of coherent electromagnetic wave interference to create very fine and specific intensity distributions of individual laser pulses. This method allows for the parallel creation of a multitude of microstructures of varying characteristics, particularly individual depressions, in the SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0079] 16
[0080] The process involves applying laser beams to a glass surface. In this way, intensity patterns are generated using superimposed coherent laser beams, which are then projected onto a component surface. Depending on the pulse length, the material is melted or even vaporized in areas of constructive interference, while it remains virtually unaffected in areas of destructive interference. The number and arrangement of the beams determine the type of pattern applied. This can be, for example, a line, cross, or dot pattern, or virtually any periodic surface pattern. The angle between the superimposed laser beams and the wavelength of the laser used determine the feature size of the applied, periodic intensity pattern. Unlike other processing methods, such as laser writing, the beam diameter does not need to be focused.
[0081] This allows a significantly larger area to be processed per laser pulse.
[0082] Simultaneously, microscopically small structures, smaller than those achievable with beam focusing, which is subject to the diffraction limit, can be generated quickly and without contact. DLIP, combined with a high-frequency laser, thus achieves processing speeds in the range of >1 m. 2 / min with the highest precision down to the nanometer range. In addition, the DLIP process has a very high depth of field compared to laser writing, since DLIP does not rely on precise focusing of the laser beam, but rather creates an "interference volume" within which the surface is structured with the corresponding interference pattern.
[0083] No additional masks or chemicals are needed, and DLIP transforms a multi-stage process into a single-stage process that is also contactless and therefore not only more sustainable but also faster.
[0084] DLIP offers a virtually endless variety of structuring possibilities through the use of nano-, pico-, or femtosecond lasers, the number of interfering laser beams and their geometry relative to each other, as well as the wavelength of the light used. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0085] 17
[0086] In one embodiment of the method according to the invention, the laser has a wavelength of 343 nm, 355 nm, 515 nm, 532 nm, 1030 nm or 1064 nm and is operated with a pulse duration of 200 fs - 15 ps, preferably with 10 ± 2 ps.
[0087] For the creation of an anti-fog structure according to the invention on float glass, a picosecond laser with a wavelength of 532 nm and a pulse duration of approximately 10 ± 2 ps is used, for example. To increase the interaction with the glass, a burst mode is employed with N > 3, i.e., with N = 3, 4, 5, 6, 7, or 8. The peak pulse power of the interference pulse is selected such that it is achieved at a fluence of approximately 30–40 J / cm². 2 within an interference pixel. This value is then independent of the number and size of the interference maxima. However, when using a femtosecond laser, the values can also be lower.
[0088] The laser structuring process "direct laser writing" (DLW) allows for the fabrication of nano- and microstructures in a photopolymer over an area of several square millimeters. This process is also known as two-photon lithography, multi-photon lithography, laser direct writing, two-photon polymerization, and multi-photon printing. Photopolymers are used to create structures in two-photon lithography. These materials have the property of hardening upon exposure to light. The wavelength required for hardening depends on the material used and the photoinitiator employed. The polymerization reaction in the photoresist can be controlled by deflecting the laser beam using movable mirrors. This can be achieved via galvanic scanners or by moving the bed on which the photoresist is located.The exposure process can be carried out layer by layer, as in other additive manufacturing processes, although this is not strictly necessary. Since the resin only reacts at the focal point of the laser beam, the beam can be guided through multiple layers, with only the desired layer hardening. Furthermore, the beam is focused very precisely, making it possible to harden parts in the resin with a diameter of less than 100 nm. The mirrors that direct the laser beam operate at high speed, allowing one hundred layers to be printed in just a few minutes. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT is used as a photopolymer.
[0089] 18
[0090] Epoxides, hybrid polymers, and hydrogels are used. Photoinitiators, some of which were developed for two-photon lithography, are used to initiate the polymerization reaction. However, it is also possible to start polymerization without a photoinitiator. By adding nanoparticles or using a hybrid polymer, it is possible to produce ceramic or preceramic structures. This method allows for the fabrication of highly precise 3D microstructures. Resolutions down to below 25 nm are achievable. The process requires no lengthy preparation and does not require a mask.
[0091] This type of laser structuring is preferably used to create raised areas on surface I and / or II of the vehicle windshield according to the present invention. The dimensions of the raised areas are selected according to the desired functionality. An anti-fog structuring preferably comprises periodic structures on surface I and / or II with a width between 5 pm and 20 pm. Periodicity refers in particular to the spacing of the individual structures (depressions or raised areas). For an anti-fog structuring, the preferred depth of the structures created by laser structuring on surface I and / or II is <500 nm, preferably <120 nm. This depth applies both to depressions extending into the volume of the glass pane and, alternatively, to raised areas measured downwards from their apex to the surface of the glass pane.
[0092] Laser structuring according to the inventive method can also be produced by laser-induced periodic surface structuring (LIPSS). Laser-induced periodic surface structures (LIPSS) form at processing intensities near the ablation threshold. Periodic structures form within the processing focus, with a structure period close to the laser wavelength used. In contrast to direct structuring, structures can be produced that are orders of magnitude smaller than the beam diameter. The formation mechanisms of LIPSS are not yet fully understood. However, it is assumed that local surface defects and surface plasmons play a role. The formation of LIPSS is polarization-dependent, and different types of LIPSS are distinguished, which form under different conditions. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0093] 19
[0094] Some key advantages of laser structuring include its environmentally friendly nature, as it requires no additional blasting or chemical agents that would otherwise require complex disposal. Furthermore, the processes are reproducible and precise, making them suitable for industrial mass production. Unlike mechanical tools used for subtractive structuring, laser processes are contactless, resulting in wear-free and low-maintenance operation. Laser structuring also leaves no residue on the surface, and the workpieces require no post-processing.
[0095] The type of glass pane is not restricted. Preferably, the glass pane is a float glass pane, a quartz glass pane, a tempered safety glass pane, or an insulating glass pane.
[0096] In a further preferred embodiment of the invention, the laser structuring is an anti-fog structuring and depressions or elevations with a width of between 3 pm and 20 pm are introduced into the surface I and / or II.
[0097] In both embodiments, the depressions or elevations can each have a depth of <500 nm, preferably <120 nm.
[0098] This makes it possible to impart a further, distinct property, namely anti-fog or dirt-repellent properties, through additional special laser structuring of an anti-reflective coating. Furthermore, it has been shown that the durability of the combined functionalization is significantly improved compared to glass panes treated only with the respective individual treatments, i.e., only structured by laser processes or only provided with a transparent coating. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0099] 20
[0100] The type of coating used in the process according to the invention is not limited. Reference is made in full to the preceding descriptions of the functional coating of the vehicle windscreen according to the invention.
[0101] The glass panes designed or manufactured according to the invention are preferably used on a vehicle, for example as a windshield, rear window or side window.
[0102] Within the scope of the present invention, all embodiments mentioned for individual features can also be freely combined with one another, provided that they are not contradictory to each other.
[0103] The invention is explained in more detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and not to scale. The drawings do not limit the invention in any way. They show:
[0104] Fig. 1 shows a schematic representation of steps a2) and b2) of a method of the present invention and
[0105] Fig. 2 shows a schematic representation of steps a1), b1) and c1) of a method of the present invention in an alternative embodiment.
[0106] Figure 1 shows a schematic representation of steps a2) and b2) of a method of the present invention. In process step a2), a glass pane 110 is provided with a transparent antireflection coating 3. Antireflection coatings are produced by coating methods of thin-film technology. Among the most frequently used methods are physical vapor deposition, such as thermal evaporation and sputtering deposition. The choice of coating method depends mainly on the desired coating material; for example, there are materials that are suitable for the SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0107] 21
[0108] thermal evaporation is not suitable. In one embodiment, the antireflection coating can be a hydrophobic coating, preferably a zirconium oxide coating. In an alternative, preferred embodiment, the transparent antireflection coating 3 is a hydrophilic coating, preferably a silicon oxide or magnesium fluoride or another suitable metal oxide coating. The antireflection coating can also have several layers of the same or, more preferably, different materials. The transparent coating 3 is applied, for example, to the glass plate 110 in a thickness of approximately 5 nm to 50 nm, preferably between 10 nm and 30 nm, and particularly preferably between 15 nm and 20 nm. In step b2), subsequent laser structuring with a possiblyThe laser structure 2 is formed in the section of the previously coated surface of the glass pane 110 by a pulsed laser 4, such that a functionality different from that of the transparent coating 3 is introduced into surface I and / or II by the laser structuring, selected from anti-fog and dirt-repellent properties. In the example shown, these are depressions 5 in the transmission area of the glass pane, wherein depressions 5 with a depth of <200 nm, preferably <120 nm, are generated in a pattern determined by interference. According to the invention, the transparent coating 3 preferably has a lesser thickness than the depth of the depressions 5 of the structuring introduced into the surface.
[0109] Figure 2 shows a schematic representation of steps a1), b1), and c1) of a method of the present invention in an alternative embodiment. In step a1), a glass pane 110 is provided, and in step b1), the laser structure 2 is formed in the section of the uncoated surface I and / or II of the glass pane 110 by laser structuring with an optionally pulsed laser 4, such that a functionality different from that of the subsequent coating, selected from anti-fog and dirt-repellent, is introduced into the surface I and / or II by the laser structuring. In the example shown, these are depressions 5 in the transmission area S of the glass pane, wherein depressions 5 with a depth of <200 nm, preferably <120 nm, are produced in a pattern determined by the laser structuring.For example, picosecond lasers with a fluence within an interference pixel SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT.
[0110] 22
[0111] from 20 - 50 J / cm² 2 preferably 30-40 J / cm² 2 , for structuring. The pulse length is preferably 10 ps. In the subsequent step c1), the structured section of the glass pane 110 is coated with a transparent anti-reflective coating 3. The coating 3 has a lesser thickness than the depth of the indentations 5 of the structuring 2 introduced into the surface. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT
[0112] 23 List of reference symbols
[0113] 100 coated glass pane with anti-fog structure 110 pane
[0114] 2 Laser structuring
[0115] 3 Anti-reflective coating
[0116] 4 lasers
[0117] 5 depressions
Claims
SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT 24 Patent claims 1. Vehicle windscreen (100) with an exposed outer surface (I), an exposed inner surface (II) and with a transmission area (S) which is provided for the optical beam path of a transmitter and / or receiver of electromagnetic radiation, and with a viewing area which comprises the field of view B or I according to ECE-R43, wherein the outer surface (I) and / or the inner surface (II) in the transmission area (S) has a transparent coating (3) and a laser structuring (2) in the coated area, characterized in that the transparent coating (3) is an anti-reflective coating, and the laser structuring (2) provides a second functionality which is different from the anti-reflective functionality, wherein the laser structuring (2) is selected from the group of anti-fog structuring and dirt-repellent structuring.
2. Vehicle windscreen according to claim 1, characterized in that the transparent coating (3) and / or the laser structuring (2) is not arranged in the viewing area of the vehicle windscreen.
3. Vehicle windscreen according to one of claims 1 or 2, characterized in that the anti-reflective coating (3) is composed of silicon dioxide, fluorinated silicon dioxide, fluorinated quartz glass, MgF2, HfO2, TiÜ2, ZrÜ2, Y2O3, silicon nitride or Gd2O3 or combinations thereof.
4. Vehicle windscreen according to one of claims 1 to 3, characterized in that the laser structuring (2) is an anti-fog structuring designed to prevent the formation of light-scattering water droplets by creating a surface with a water contact angle of <20°, preferably <10°.
5. Vehicle windscreen according to one of claims 1 to 4, characterized in that the laser structuring (2) is an anti-fog structuring which has periodic structures in the surface (I) with a periodicity of between 5 pm and 20 pm.
6. Vehicle windscreen according to one of claims 1 to 4, characterized in that the laser structuring (2) is a dirt-repellent structuring which is SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT 25 is designed to reduce the adhesion of dirt by creating a surface with a water contact angle of >90°, preferably >120°.
7. Vehicle windscreen according to one of claims 1 to 6, characterized in that the depth of the structures present in the surface (I) by laser structuring is <500 nm, preferably <120 nm.
8. Vehicle windscreen according to one of claims 1 to 7, characterized in that the laser structuring (2) is formed either by indentations (5) or by a cone-like structure in the surface (I) and / or (II).
9. Method for manufacturing a vehicle windscreen (100) with an exposed outer surface (I), an exposed inner surface (II) and with a transmission area (S) which is provided for the optical beam path of a transmitter and / or receiver of electromagnetic radiation, and with a viewing area which in particular comprises the field of view B or I according to ECE-R43, wherein the outer surface (I) and / or the inner surface (II) in the transmission area (S) is first provided with a transparent anti-reflective coating (3) and a structure (3) is introduced into the surface (I) and / or (II) so coated by means of a laser (4), which is selected from the group of anti-fog structures and dirt-repellent structures, or wherein a structuring (3) selected from the group of anti-fog structuring and dirt-repellent structuring is first introduced into the outer surface (I) and / or the inner surface (II) in the transmission area (S) by means of a laser (4), and the surface (I) and / or (II) thus structured is provided with a transparent coating (3) selected from the group of anti-fog coatings and dirt-repellent coatings.
10. The method of claim 9, characterized in that the vehicle window (100) is a float glass pane, a quartz glass pane, a tempered safety glass pane, or an insulating glass pane. SAINT-GOBAIN SEKURIT FRANCE 2025083-WO-PCT 26 11. Method according to claim 9 or 10, characterized in that the laser structuring is carried out by means of Direct Laser Writing (DLW), Direct Laser Interference Patterning (DLIP) or Laser-induced Periodic Surface Structuring (LIPSS).
12. Method according to one of claims 9 to 11, characterized in that the laser structuring is an anti-fog structuring and depressions (5) or elevations with a width of between 3 pm and 20 pm are introduced into the surface (I) and / or (II).