Roof for a vehicle

Abstract

The present invention relates to a roof for a vehicle Such roof comprises an external glass sheet, an internal glass sheet and an interlayer between the internal glass sheet and the external glass sheet. At least one edge of the roof comprises at least two inflection points. These at least two inflection points define one cavity. Such cavity comprises a central curvature radius and two side curvature radii.

Description

Roof for a vehicleFIELD OF THE INVENTION

[0001] The present invention relates to the field of vehicle’s roof. More specifically it relates to a glass roof with a cavity to house an optical sensor.BACKGROUND OF THE INVENTION

[0002] Nowadays vehicles comprise an increasing number of devices and systems to assist and even to replace the driver. A vehicle includes cars, vans, lorries, motorbikes, buses, trams, trains, airplanes, helicopters, drones, boats and the like. The trend is moving towards fully autonomous vehicles able to manage various situations by themselves. Various optical sensors are therefore needed in order for the vehicle to assess the situation encountered, such as cameras, radars and lidars. These optical sensors usually comprise a cover to protect the detection system. This cover is transparent at the operating wavelength of the optical sensor. It can be made of glass, plastics or a combination thereof.

[0003] The incorporation of such optical sensors into a vehicle is more and more challenging, and usually perturbs the aerodynamics of the vehicle, as well as its aesthetics.

[0004] W02018015312 describes the integration of an infrared-based remote sensing device such as a lidar behind a window of a vehicle, such as behind a windshield. It allows to preserve the aerodynamics of the vehicle, but impacts the internal compartment of the vehicle. Indeed the area around the rearview mirror tends to welcome more and more optical sensors, leading to an imposing central zone on the ceiling which can be disturbing.

[0005] US2018037267 describes a vehicle roof structure comprising a spoiler which hides some sensors. However, such spoiler has a negative impact on the aerodynamics of the vehicle.

[0006] There is therefore a need for a solution to integrate optical sensors into a vehicle while both minimizing the impact on the aerodynamics and replying to the request from vehicle manufacturers to optimize the aesthetics of such vehicle.SUMMARY OF THE INVENTION

[0007] The present invention concerns a roof for a vehicle. Such roof comprises an external glass sheet, an internal glass sheet and an interlayer between the internal glass sheet and the external glass sheet. At least one edge of the roof comprises at least two inflection points. These at least two inflection points define one cavity. Such cavity comprises a central curvature radius and two side curvature radii.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig.1 illustrates an assembly comprising a roof according to the present invention.

[0009] Fig.2 illustrates an exploded view of such assembly.

[0010] Fig.3 illustrates a roof according to the present invention.

[0011] Fig.4a illustrates the curvature of the centre of the cavity of a roof according to the present invention.

[0012] Fig.4b illustrates the curvature of the sides of the cavity of a roof according to the present invention.DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0013] The invention will now be described further, byway of examples, with reference to the accompanying drawings, wherein like reference numerals refer to like elements in the various figures. These examples are provided by way of illustration and not of limitation. The drawings are a schematic representation and not true to scale. The drawings do not restrict the invention in any way. More advantages will be explained with examples.

[0014] In this document to a specific embodiment and include various changes, equivalents, and / or replacements of a corresponding embodiment. The same reference numbers are used throughout the drawings to refer to the same or like parts.

[0015] As used herein, spatial or directional terms, such as "inner", "outer", "above", "below", "top", "bottom", and the like, relate to the invention as it is shown in the drawing figures. However, it is to be understood that the invention can assume various alternative orientations and, accordingly, such terms are not to be considered aslimiting. Further, all numbers expressing dimensions, physical characteristics, processing parameters, quantities of ingredients, reaction conditions, and the like, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical values set forth in the following specification and claims are approximations that can vary depending upon the desired properties sought to be obtained by the present invention. In the following description, unless otherwise specified, expression “substantially” mean to within 10%, preferably to within 5%.

[0016] Moreover, all ranges disclosed herein are to be understood to be inclusive of the beginning and ending range values and to encompass any and all subranges subsumed therein. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more, e.g. 1 to 6.1 , and ending with a maximum value of 10 or less, e.g., 5.5 to 10. Further, as used herein, the terms “deposited over” or “provided over” mean deposited or provided on but not necessarily in surface contact with. For example, a coating “deposited over” a substrate does not preclude the presence of one or more other coating films of the same or different composition located between the deposited coating and the substrate.

[0017] Where the term “comprising” is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun e.g. “a” or “an”, “the”, this includes a plural of that noun unless something else is specifically stated. In this document, “configured to (or set to)” may be interchangeably used in hardware and software with, for example, “appropriate to”, “having a capability to”, “changed to”, “made to”, “capable of”, or “designed to” according to a situation. In any situation, an expression “device configured to do” may mean that the device “can do” together with another device or component.

[0018] Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriatecircumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. When it is described that a constituent element (e.g., a first constituent element) is “(functionally or communicatively) coupled to” or is “connected to” another constituent element (e.g., a second constituent element), it should be understood that the constituent element may be directly connected to the another constituent element or may be connected to the another constituent element through another constituent element (e.g., a third constituent element).

[0019] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims.

[0020] While some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.Roof

[0021] The present invention proposes a roof for a vehicle. A vehicle includes cars, vans, lorries, motorbikes, buses, trams, trains, airplanes, helicopters, drones, boats and the like.External glass sheet

[0022] The roof comprises an external glass sheet. By external, it means the glass sheet is in contact with the environment external to the vehicle.

[0023] In some embodiments, the external glass sheet is made of mineral glass, more specifically a silica-based glass, such as soda-lime-silica, alumino-silicate or borosilicate type glass.

[0024] The external glass sheet according to the invention may be obtained by a floating process, a drawing process, a rolling process or any other process known to manufacture glass sheet starting from a molten glass composition.

[0025] In some embodiments, the external glass sheet is a float glass sheet. The term “float glass sheet” is understood to mean a glass sheet formed by the float glassprocess, which consists in pouring the molten glass onto a bath of molten tin, under reducing conditions.

[0026] In some embodiments, the external glass sheet is thicker compared to the internal glass sheet. The reflection optics is critical for roofs, and the thicker the external glass sheet, the better the optics.

[0027] In some embodiments, the external glass sheet ranges from 1 ,5mm to 4mm in thickness.Internal glass sheet

[0028] The roof further comprises an internal glass sheet. By internal, it means the glass sheet is in contact with the interior of the vehicle.

[0029] In some embodiments, the internal glass sheet is made of mineral glass, more specifically a silica-based glass, such as soda-lime-silica, alumino-silicate or borosilicate type glass.

[0030] The internal glass sheet according to the invention may be obtained by a floating process, a drawing process, a rolling process or any other process known to manufacture glass sheet starting from a molten glass composition.

[0031] In some embodiments, the internal glass sheet is a float glass sheet. The term “float glass sheet” is understood to mean a glass sheet formed by the float glass process, which consists in pouring the molten glass onto a bath of molten tin, under reducing conditions.

[0032] In some embodiments, the internal glass sheet is thinner compared to the external glass sheet to provide structural strength and safety.

[0033] In some embodiments, the internal glass sheet ranges from 0.7mm to 2.1 mm in thickness.Laminate

[0034] The roof further comprises an interlayer laminating the internal glass sheet and the external glass sheet together. Such configuration is usually referred to as laminated glass. Laminated glass is a type of safety glass that is commonly used in various applications, including windows, windshields, and architectural structures. It is designed to provide enhanced safety and security compared to standard glass.

[0035] Laminated glass is composed of two or more glass sheets which are bonded together with a polyvinyl butyral (PVB) interlayer or an ethylene-vinyl acetate (EVA) interlayer. The interlayer is a tough and transparent plastic material that holds the glass sheets together. In the event of breakage, the interlayer holds the shattered glass pieces together, preventing them from separating and reducing the risk of injury from sharp glass fragments. This is why laminated glass is often referred to as safety glass.

[0036] In some embodiments, the interlayer is an acoustic interlayer, allowing to reduce the noise produced within the laminate, and therefore enhancing the auditive comfort of the passengers of the vehicle.

[0037] Another possibility to laminate the internal glass sheet and the external glass sheet together is to use optically clear adhesive (OCA), possibly liquid OCA (LOCA).

[0038] OCA is a dry adhesive film that is optically transparent and provides excellent bonding properties. It is used for laminating automotive glass, particularly for applications such as heads-up displays (HUDs) and instrument clusters. Key features and benefits of OCA in the automotive industry include: optical clarity by maintaining the transparency and optical quality of the glass, ensuring clear visibility for the driver and passengers, bonding strength by providing strong adhesion between the glass layers, enhancing the structural integrity of the laminated glass, vibration damping by helping to reduce vibrations and noise transmission, resulting in a quieter and more comfortable cabin environment, UV resistance, easy installation as OCA is available in pre-cut shapes and sizes, making it easier to handle and install during the manufacturing process.

[0039] LOCA is a liquid adhesive that is applied in a liquid form between the glass sheets and then cured to form a solid, optically clear bond. LOCA is commonly used in the assembly of automotive windshields and panoramic roofs. Key features and benefits of LOCA in the automotive industry include: optical clarity by providing excellent transparency, ensuring high optical quality and minimal distortion in the laminated glass, bonding strength by forming a strong bond between the glass layers, enhancing the structural integrity of the windshield or panoramic roof, impact resistance by helping to improve the impact resistance of the glass, reducing the risk of shattering and enhancing passenger safety, UV resistance and customizableviscosity as LOCA is available in different viscosities, allowing manufacturers to choose the appropriate adhesive consistency for their specific application.

[0040] Both OCA and LOCA interlayers are designed to meet stringent automotive industry standards for safety, durability, and optical performance. They contribute to the overall strength and reliability of laminated automotive glass, providing enhanced protection to vehicle occupants and improving the driving experience.

[0041] In some embodiments, the total thickness of the laminate in a transparent roof laminate ranges from approximately 5mm and 10mm, depending on the specific design and safety requirements.Inflection points

[0042] At least one edge of the roof comprises at least two inflection points. An edge is understood as a border of the roof, said otherwise a line corresponding to a limit of the roof. An edge of the roof therefore comprises an edge of the external glass sheet, an edge of the interlayer and an edge of the internal glass sheet.

[0043] It is understood that more than one edge can comprise at least two inflection points.

[0044] An inflection point is defined as a point at which the sign of the curvature (i.e. , the concavity) changes.

[0045] As at least one edge of the roof comprises two inflection points, these two inflection points define a cavity. Such cavity comprises therefore a central curvature radius and two side curvature radii. In some embodiments, the two side curvature radii are the same for symmetry.

[0046] It is to be noted that an edge can comprise more than two inflection points. In case of four inflection points, two separate cavities are defined. In case of six inflection points, three separate cavities are defined.

[0047] In some embodiments, the number of inflection points is preferably even, in order for the roof to be symmetrical, rendering easier the integration of the roof on a vehicle.

[0048] In some embodiments, the two inflection points are separated by a distance of at least 150mm. Such distance between them allows to create a cavity which issufficiently voluminous.

[0049] In some embodiments, the central curvature radius of the cavity is comprised between 150mm and 7500mm, preferably between 300mm and 5000mm, more preferably between 400mm and 2000m, even more preferably between 800mm and 1500mm.

[0050] In some embodiments, the side curvature radii are equal, and comprised between 150mm and 7500mm, preferably between 300mm and 5000mm, more preferably between 400mm and 2000m, even more preferably between 800mm and 1500mm.

[0051] The process of bending glass involves heating the glass to a high temperature until it becomes soft and pliable, and then shaping it into the desired form. There are several methods used for bending glass, including heat bending, gravity bending, press bending and blow bending.

[0052] Press bending involves heating the glass and then pressing it between two molds or plates to achieve the desired shape. The molds can be either convex or concave, depending on the desired curvature of the glass.

[0053] In order to form the roof, the external glass sheet and the internal glass sheet are laminated together with an interlayer. The bending of the external glass sheet and the internal glass sheet can be done either before (sheet-by-sheet process) or after lamination (two-sheet process).

[0054] In sheet-by-sheet process, both the external glass sheet and the internal glass sheet can be bent by press bending in order for at least one edge of the internal glass sheet and the corresponding at least one edge of the external glass sheet to comprise at least two inflection points. The external glass sheet and the internal glass sheet are then aligned and an interlayer placed between them in order to form the laminate. Lamination process is well known by the person skilled in the art. This method is preferred as it allows for higher quality and better feasibility.

[0055] Two-sheet bending involves bending the internal glass sheet and the external glass sheet together with an interlayer, and then press bending the laminate itself.Assembly

[0056] The present invention further relates to an assembly. The assembly comprisesa roof as described previously.Glass cover

[0057] The assembly further comprises at least one glass cover at least partially closing the cavity. By at least partially closing the cavity, it means that the cavity is at least partially closed on the edge side, meaning on the edge with the two inflection points.

[0058] In some embodiments, the glass cover is made of mineral glass, more specifically a silica-based glass, such as soda-lime-silica, alumino-silicate or borosilicate type glass.

[0059] The glass cover may be glass obtained by a floating process, a drawing process, a rolling process or any other process known to manufacture glass starting from a molten glass composition.

[0060] In some embodiment, the glass cover is a float glass cover. The term “float glass cover” is understood to mean a glass cover formed by the float glass process, which consists in pouring the molten glass onto a bath of molten tin, under reducing conditions.

[0061] In some embodiments, instead of a glass cover, a plastic cover could be used.Attaching means

[0062] The assembly further comprises attaching means to connect the at least one glass cover to the roof.

[0063] Such attaching means are well known by the person skilled in the art.

[0064] In some embodiments, the attaching means can be formed by a piece on which the glass cover is attached, and this piece is attached to the roof. The attachment of the glass cover to the piece and of the piece to the roof can be performed by glue or through encapsulation or through polyurethane pouring.Optical sensor

[0065] In some embodiments, the assembly further comprises at least one optical sensor positioned within the cavity. An optical sensor is understood as a device that detects and measures electromagnetic radiation in the optical range of the electromagnetic spectrum, including visible wavelength range (480nm - 780nm) andnear-infrared wavelength range (780nm - 1650nm). The optical sensor can only detect electromagnetic radiation, such as a camera. The optical sensor can also both send and detect electromagnetic radiation, such as a radar or a lidar.

[0066] In some embodiments, the optical sensor is a lidar. Lidar is an acronym for “light detection and ranging”. It is sometimes called “laser scanning” or “3D scanning”. The technology uses laser beams to create a 3D-representation of the surveyed environment. Operating wavelength of lidar compatible with the present invention is comprised between 800nm and 1650nm (usually referred to as near-infrared). More specifically, known operating wavelengths of currently produced lidars compatible with the present invention are 850nm, 905nm, 940nm, 1064nm, 1310nm, 1350nm, 1550nm. An acceptable variance of 25nm around the nominal value of the operating wavelength may be considered, such that, for example, a wavelength range of 1525nm to 1575nm may be accepted around the nominal value of 1550nm.

[0067] In some embodiments, the optical sensor is attached to the roof through connecting means. Such connecting means could be a molded plastic part which is glued to the internal glass sheet of the roof.

[0068] In some embodiments, an enamel could be printed on either and / or both faces of the internal glass sheet and / or of the interlayer and / or of the external glass sheet to hide the optical sensor and the connecting means from the external environment.

[0069] In some embodiments, the glass cover is installed normal to the central beam of the optical sensor. This allows to have an angle of incidence of the central beam of the optical sensor equal to 0°, and therefore to decrease the signal losses.

[0070] In optics, the central beam refers to the principal ray. It is an imaginary line that represents the path of electromagnetic radiation traveling through the center of an optical system. In the case of an optical sensor, the central beam can be understood as the primary light path that interacts with the sensor's active area. It typically corresponds to the optical axis of the sensor, which is an imaginary line passing through the center of the sensor's field of view.

[0071] In some embodiments, the central beam of the optical sensor has an incident angle to the normal to the glass cover comprised between 0° and 75°, preferably between 8° and 60°, more preferably between 11 ° and 40°.

[0072] The present invention also relates to the use of a roof as described previously, to house an optical sensor in the cavity formed by the at least two inflection points.

[0073] An example of an assembly (50) according to the present invention is shown in Fig.1 This assembly (50) comprises a roof (1 ). An edge (100) of the roof (1 ), in this example the front edge (100), comprises two inflection points defining a cavity (2). This cavity (2) is closed by a glass cover (20). The glass cover (20) is attached to the roof (1 ) by attaching means (21 ).

[0074] Fig.2 shows an exploded view of the assembly (50). The assembly comprises a roof (1 ).

[0075] The roof (1 ) comprises an external glass sheet (11 ), an interlayer (12) and an internal glass sheet (13). One of the edges of the roof (1 ) comprises two inflection points defining a cavity (2).

[0076] An optical sensor (3) is housed in the cavity (2). The optical sensor (3) is attached to the roof (1 ) through connecting means (31 ). In this example, the connecting means (31 ) are made of a molded plastic part which is glued to the internal glass sheet (13) of the roof (1 ).

[0077] The cavity (2) is closed by a glass cover (20), which is attached to the roof (1 ) by attaching means (21 ). In this example, the attaching means (21 ) are formed by a molded plastic part which is clipped to the connecting means (31 ). The attaching means (21 ) encapsulates the glass cover (20).

[0078] In this example, the internal glass sheet (13) comprises an enamel (9) printed along its periphery in order to dissimulate the optical sensor (3) as well as the connecting means (31 ). The enamel (9) is printed on the face of the internal glass sheet (13) opposite to the interlayer (12). However, such enamel (9) could be printed on either faces of the internal glass sheet (13), as well as on either faces of the external glass sheet (11 ), as well as on either faces of the interlayer (12).

[0079] Fig.3 shows a roof (1 ) according to the present invention. In this example, the front edge of the roof (1 ) comprises two inflection points (101 ). The curvature of the edge changes of sign at each of the inflection points (101 ). These two inflection points (101 ) define a cavity (2).

[0080] Fig.4a shows a roof (1 ) according to the present invention. In this example, thefront edge of the roof (1 ) comprises two inflection points (101 ). The curvature of the edge changes of sign at each of the inflection points (101 ). These two inflection points (101 ) define a cavity (2). The curvature of the centre of the cavity (2) is highlighted by a part of the circle. In this example, the central curvature radius of the cavity (2) is 1100mm.

[0081] Fig.4b shows a roof (1 ) according to the present invention. In this example, the front edge of the roof (1 ) comprises two inflection points (101 ). The curvature of the edge changes of sign at each of the inflection points (101 ). These two inflection points (101 ) define a cavity (2). The curvature of the sides of the cavity (2) is highlighted by two dashed lines partial circles. In this example, the side curvature radii of the cavity (2) are identical and are equal to 1100mm.

[0082] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention may be practiced in many ways. The invention is not limited to the disclosed embodiments.

Claims

Claims1. Roof (1 ) for a vehicle comprising: a) An external glass sheet (11 ); b) An internal glass sheet (13); c) An interlayer (12) between the internal glass sheet (13) and the external glass sheet (11 );Characterized in that at least one edge of the roof (1 ) comprises at least two inflection points (101 ) defining one cavity (2), the cavity (2) comprising a central curvature radius and two side curvature radii.

2. Roof (1 ) according to claim 1 , wherein the two side curvature radii are equal.

3. Roof (1 ) according to any one of the preceding claims, wherein the at least two inflection points (101 ) are separated by a distance of at least 150mm.

4. Roof (1 ) according to any one of the preceding claims, wherein the central curvature radius of the cavity (2) is comprised between 150mm and 7500mm, preferably between 300mm and 5000mm, more preferably between 400mm and 2000m, even more preferably between 800mm and 1500mm.

5. Roof (1 ) according to any one of the preceding claims, wherein the side curvature radii of the cavity (2) are comprised between 150mm and 7500mm, preferably between 300mm and 5000mm, more preferably between 400mm and 2000m, even more preferably between 800mm and 1500mm.

6. Roof (1 ) according to any one of the preceding claims, wherein the thickness of the external glass sheet (11 ) is comprised between 1 ,5mm and 4mm.

7. Roof (1 ) according to any one of the preceding claims, wherein the thickness of the internal glass sheet (11 ) is comprised between 0.7mm and 2.1 mm.

8. Roof (1 ) according to any one of claims 1 to 7, wherein the interlayer (12) is a polyvinyl butyral interlayer or an ethylene-vinyl acetate interlayer.

9. Roof (1 ) according to any one of claims 1 to 7, wherein the interlayer (12) is an acoustic interlayer.optically clear adhesive or a liquid optically clear adhesive.11 . Assembly (50) comprising: a) a roof (1 ) according to any one of claims 1 to 10; b) at least one glass cover (20) at least partially closing the cavity (2); c) attaching means (21 ) to connect the at least one glass cover (20) to the roof (1 ).

12. Assembly (50) according to claim 11 , wherein the at least one glass cover (20) is attached to the attaching means (21 ) by glue, through encapsulation or through polyurethane pouring.

13. Assembly (50) according to any one of claims 11 to 12, further comprising at least one optical sensor (3), the at least one optical sensor (3) being positioned within the cavity (2).

14. Assembly (50) according to claims 13, wherein a central beam of the optical sensor (3) has an incident angle to the normal to the glass cover (20) comprised between 0° and 75°, preferably between 8° and 60°, more preferably between 11 ° and 40°.

15. Use of a roof (1 ) according to any one of claims 1 to 10, to house an optical sensor (3) in the cavity (2) formed by the at least two inflection points (101 ).

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