Laminated glazing for projecting images from a head-up display (HUD)

Abstract

A laminated glazing 10 for a head-up display (HUD) (5) is described. The laminated glazing (10) has an outer glass pane (1) and an inner glass pane (2) bonded to each other via a thermoplastic interlayer (3). The thickness of the interlayer (layer 3) in a vertical course (C) between a lower edge L and an upper edge U of the laminated glazing (10) varies within at least one or more sections between two imaginary points P1 and P2 taken along the vertical course (C). In accordance with the invention, the calculated surface area (S) enclosed by the straight lines connecting a first value V1 defined by the position (d(1)) and thickness (Tk(1)) of imaginary point P1 with a final value V2 defined by the position (d(2)) and thickness (Tk(2)) of imaginary point P2 is greater than 10,000 mm x μm.

Description

[Technical field]

[0001] The present invention relates to a laminated glazing and projection arrangement for a head up display, a method for manufacturing a windshield adapted for a HUD (head up display). [Background technology]

[0002] The present invention relates to a laminated glazing and projection arrangement for a head-up display, a method for manufacturing the laminated glazing, and uses thereof.

[0003] Modern automobiles are increasingly equipped with so-called head-up displays (HUDs). By means of a projector, for example in the area of ​​the dashboard or in the roof area, an image is projected onto the windshield, where it is reflected and perceived by the driver (from his point of view) as a virtual image behind the windshield. Thus, important data can be projected into the driver's field of vision, such as, for example, the current driving speed, navigation or warning messages, which the driver can perceive without the need to divert his gaze from the road. Thus, head-up displays can make a significant contribution to improving road safety.

[0004] In the case of the head-up displays mentioned above, a problem arises in that the projector image is reflected on both surfaces of the windshield. As a result, the driver perceives not only the desired primary image, but also a slightly offset secondary image, which is usually weaker in intensity. This secondary image is commonly referred to as a ghost image. This problem is generally solved by placing both reflective surfaces at an angle in relation to each other that is purposely selected so that the primary and ghost images coincide, so that the ghost image can no longer be perceived in a distracting manner. In prior art laminated glazing for head-up displays, the wedge angle is typically around 0.5 mrad.

[0005] A windshield has two glass panes laminated to each other via a thermoplastic interlayer. When the surfaces of the glass panes need to be arranged at an angle, as mentioned above, it is customary to use a thermoplastic interlayer with a non-constant thickness. This is also called a wedge-shaped interlayer or wedge interlayer. The angle between the two surfaces of the interlayer is called the wedge angle. The wedge angle can be constant over the entire interlayer (linear change in thickness) or it can vary depending on the position (non-linear change in thickness). Laminated glass with a wedge interlayer is known, for example, from WO 2009 / 071135 A1, EP 1 800 855 B1 or EP 1 880 243 A2.

[0006] The wedge interlayer is typically manufactured by extrusion, where a wedge-shaped extrusion die is used. Manufacturing a wedge interlayer with the desired wedge angle depending on the specific pane shape and projection configuration of the head-up display among other things is very costly and complicated.

[0007] Generally, wedge-shaped interlayers, and more specifically PVB (polyvinyl butyral) panes, are obtained by stretching the interlayer, such that the stretched interlayer presents a non-linear thickness profile in comparison to the profile produced by directly connecting the thickest and thinnest points, such that the interlayer is relatively thin in the central area of ​​the windshield when the interlayer is laminated between at least two glass panes.

[0008] However, when a non-linear wedge-shaped interlayer is laminated between at least two glass panes, the degassing process in the lamination process usually used in the automotive field is insufficient, which leads to the presence of air bubbles on the inside of the laminated glazing. This problem is even more pronounced when the interlayer is composed of multiple layers of interlayers, such as the multiple interlayers used in windshields with wedge PVB with sound absorbing function, to limit ghost images and improve the sound absorbing performance by the presence of a soft so-called core layer.

[0009] The root cause of this defect is residual air in the central area of ​​the windshield, where the intermediate layer has a concave shape.

[0010] The more pronounced the concave shape of the intermediate layer, the more severe the bubble phenomenon that occurs within the windshield.

[0011] Therefore, a need exists for an improved laminated glazing for head-up displays (HUDs) that is less susceptible to ghost images of the HUD projection.

[0012] Another object of the present invention is to provide a method for producing improved laminated glazing for head-up displays (HUDs) with improved yields by avoiding or reducing the formation of air bubbles in the lamination process. Summary of the Invention [Problem to be solved by the invention]

[0013] It is an object of the present invention to provide an improved laminated glazing for head-up displays which is more efficient, economical and simpler to manufacture than prior art laminated glazing of this type. [Means for solving the problem]

[0014] The object is achieved according to the invention by a laminated glass according to claim 1. Preferred embodiments emerge from the dependent claims.

[0015] To this end, the present application 1. A laminated glazing for a head-up display (HUD), the glazing having an upper edge and a lower edge, the glazing comprising: an outer pane and an inner pane joined together via a thermoplastic intermediate layer; a HUD region in which a virtual image is generated by a HUD projector; Including, the windshield is provided with strips of enamel along its edges, the strips of enamel (M1, M2) being respectively within the lower and upper edges of the windshield, the strips of enamel (M1, M2) each having an inner edge (N1, N2) in contact with a zone where no enamel is present, Glazing is imaginary horizontal lines (Z1, Z2) parallel to the lower and upper strips (M1, M2) of enamel respectively and spaced apart from the inner edges (N1, N2) of the enamel (M1, M2) by a distance Y equal to 50 mm; a vertical course (C) from the upper edge and the lower edge, the vertical course passing through the HUD area; a virtual point P1 which is an intersection of a horizontal virtual line and a vertical course; a virtual point P2 which is an intersection of the horizontal virtual line and the vertical course; Including, Imaginary points P1 and P2 are separated by an imaginary vertical line d along a vertical course (c) in a zone free of enamel along the vertical course, the thickness of the interlayer has a monotonically increasing wedge angle (α) in a vertical course between the imaginary points P1 and P2, the thickness at the P2 point being greater than the thickness at the P1 point, and the interlayer along the windshield has a minimum thickness of 900 μm between the imaginary points P1 and P2 in the enamel-free zone area along the vertical course; The thickness profile of the intermediate layer in the vertical course is defined by a set of n values ​​(V) defined by the position (d(n)) and thickness (Tk(n)) measured from imaginary points P1 and P2 along an imaginary line d separating the imaginary points P1 and P2 to calculate the surface area (S); The Company offers laminated glazing for head-up displays (HUD).

[0016] According to the invention, the calculated surface area (S) is surrounded by a line connecting a first value V1 defined by the position (d(1)) and thickness (Tk(1)) of a virtual point P1 to a final value V2 defined by the position (d(2)) and thickness (Tk(2)) of a virtual point P2, and a thickness profile defined by the series of n values ​​(V) described above, and has a surface area of ​​10,000 mm × It is over μm.

[0017] In the laminated glazing for a head-up display (HUD) according to the present invention, the wedge angle (a) defined by P1 and P2 is between 0.05 mrad and 0.5 mrad.

[0018] The laminated glazing according to the present invention for a head-up display (HUD) has an upper edge and a lower edge. The term "upper edge" means the side edge of the laminated glass that is intended to point upward in the installed position. The "lower edge" means the side edge that is intended to point downward in the installed position. When the laminated glass is a windshield of a motor vehicle, the upper edge is often referred to as the "roof edge" while the lower edge is referred to as the "engine edge".

[0019] The laminated glazing according to the invention comprises an outer pane and an inner pane interconnected via a thermoplastic interlayer. The laminated glazing is intended to separate the interior from the outside environment in an opening, in particular in a window opening of a motor vehicle. In the context of the present invention, "inner pane" means the pane of the laminated glazing facing the interior (interior of the motor vehicle). "Outer pane" means the pane facing the outside environment.

[0020] The thickness of the interlayer varies at least within a plurality of sections in a vertical course between the lower and upper edges of the laminated glass, with a maximum wedge angle α of 0.5 mrad or less, more preferably 0.4 mrad or less, with the wedge angle having a finite wedge angle, i.e., a wedge angle greater than 0°, at least within a plurality of sections. Here, the term "within a plurality of sections" means that the vertical course between the lower and upper edges has at least one section in which the thickness of the interlayer varies with position. However, the thickness of the interlayer can also vary within a plurality of sections or throughout the entire vertical course.

[0021] The term "vertical course" means a course between an upper edge and a lower edge, with the direction of the course being substantially perpendicular to the upper edge. Since in a windshield the upper edge may deviate significantly from a straight line, the vertical course in the context of the present invention is more accurately expressed as being perpendicular to a connecting line between two corners of the upper edge.

[0022] "Wedge angle" means the angle between the two surfaces of an interlayer. If the wedge angle is not constant, then a line tangent to the surfaces must be used to measure it at a given point.

[0023] Conventionally, the edge of the windshield is provided with a strip of enamel to hide and / or protect from UV the electrical connections or elements glued on the windshield. The width of the enamel strip is generally determined by the passenger car manufacturer depending on the items to be hidden / protected by the enamel. The enamel strip, which is located on the upper and lower edges of the windshield, has two opposite parts, one in contact with the edge of the windshield (upper or lower edge) and one in contact with a zone (F) where no enamel is present.

[0024] According to one embodiment of the present invention, the edge of the windshield is provided with a thermoplastic interlayer having a light transmittance of less than 5% to conceal and / or protect from UV the electrical connections or elements glued on the windshield. The thermoplastic interlayer may be a printed or colored black PVB. The width of the "black band" formed by the thermoplastic interlayer is generally determined by the passenger car manufacturer depending on the item to be concealed / protected by the "black" interlayer. The "black" interlayer, which is arranged on the upper and lower edges of the windshield, has two opposite parts, one in contact with the edge of the windshield (upper or lower edge) and one in contact with the zone (F) where the "black" interlayer is not present.

[0025] Therefore, the present invention proposes a method to prevent insufficient degassing in the lamination process by increasing the minimum thickness to fill any gaps that the bent glass may have. The intermediate thermoplastic layer, and more specifically the PVB, is thick and soft enough to fill all the spaces and to ensure a good level of degassing performance.

[0026] The present invention surprisingly shows that by defining the steepness of the re-entrant shape by a parameter (S), the relationship between thickness profile and thickness solves the above cited problems.

[0027] The advantage of the present invention lies in the fact that when using an interlayer as described above, the formation of air bubbles inside the laminated glass is limited and in some cases eliminated, thus increasing the time life of the laminated glass and avoiding ghost images.

[0028] According to one embodiment of the present invention, the laminated glazing for a head-up display (HUD) is a vehicle windshield (particularly of a motor vehicle, for example an automobile) onto which a virtual image from a projector is projected. As is customary for HUDs, a projector illuminates an area of ​​the windshield, which is reflected towards an observer (driver) to generate a virtual image that the observer perceives from his / her point of view as being behind the windshield. The area of ​​the windshield that can be illuminated by the projector is called the HUD area. The projector is aimed at the HUD area. The direction of the projector illumination can be changed, usually by mirrors, specifically in the vertical direction, to adapt the projection to the observer's body size. The area in which the observer's eyes must be located with a given mirror position is called the eyebox window. This eyebox can be shifted in the vertical direction by adjusting the mirrors, and the total area thus available (i.e. the overlay of all possible eyebox windows) is called the eyebox. An observer located within the eyebox can perceive the virtual image, which of course means that, for example, the observer's eyes, but not their whole body, must be located within the eyebox.

[0029] The beam that extends between the projector and the center of the eyebox is commonly referred to as the central beam. This is the characteristic reference beam for the design of HUD projection configurations.

[0030] According to the invention, the interlayer has a thickness in the vertical course (C) of more than 900 μm, preferably more than 1000 μm, more preferably more than 1100 μm along the entire thickness. The interlayer has a thickness in the vertical course (C) of preferably less than 2000 μm, preferably less than 1800 μm, more preferably less than 1400 μm. In a further preferred embodiment, the interlayer has a thickness of 1100 μm to 1400 μm. Within this thickness range of 1100 μm to 1400 μm, the degassing is improved. In the case of a thickness of less than 1100 μm, the surface roughness of the interlayer facing the inner or outer glass, the so-called embossment, is excessively small, which results in the difficulty of completely removing the air trapped between the interlayer and the glass sheet, which results in the phenomenon of bubbles. At thicknesses above 1400 μm, the total glass thickness is excessively thick, resulting in a different optimal wedge angle than is targeted, which may result in ghosting of the HUD image. The interlayer has a finite wedge angle, i.e., a wedge angle greater than 0°, at least in sections, i.e., in sections of varying thickness.

[0031] The term "wedge angle" means the angle between the two surfaces of an interlayer. If the wedge angle is not constant, then a line tangent to the surfaces must be used to measure it at a given point.

[0032] The wedge angle varies, at least within the HUD region. Preferably, the thickness and wedge angle increase monotonically in the vertical course from the lower edge of the HUD region to the upper edge of the HUD region.

[0033] The present invention is based on the discovery that the undesirable phenomenon of bubble formation inside the windshield and its amplification by varying the wedge angle is positively linked to the thickness of the interlayer. The use of a relatively thick interlayer having the properties cited above allows a significant reduction in the formation of bubbles during the degassing process of the windshield lamination.

[0034] Thus, a relatively thick interlayer can compensate for gaps between the glass panes when the glass is bent, such that the interlayer can flow across gaps that potentially exist between the bent glass panes.

[0035] The HUD viewing field is the zone on the windshield onto which the image is projected by the HUD's projector unit. The position and size of the HUD viewing field will, of course, vary according to the vehicle and, consequently, the windshield model.

[0036] The (varying) wedge angle is preferably 0.05 mrad to 0.5 mrad within the HUD area, and particularly preferably 0.1 mrad to 0.4 mrad, as a result of which good results are obtained in terms of ghost image suppression in a normal head-up display.

[0037] The outer and inner panes preferably comprise glass, in particular soda-lime glass. However, the panes may in principle also comprise other types of glass, such as quartz glass or borosilicate glass, or possibly also rigid clear plastics, in particular polycarbonate or polymethylmethacrylate. The thickness of the outer and inner panes may vary widely. Advantageously, the individual panes have a thickness which is in each case a maximum of 5 mm, preferably a maximum of 3 mm. Preferably panes with a thickness in the range of 0.8 mm to 5 mm, preferably 1.4 mm to 2.5 mm, such as for example those with a standard thickness of 1.6 mm or 2.1 mm, are used.

[0038] The thermoplastic interlayer comprises at least a thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) or polyurethane (PU) or a mixture or copolymer or derivative thereof, particularly preferably PVB. According to the invention, the thermoplastic bonding interlayer has a minimum thickness of 900 μm, particularly preferably from 900 μm, preferably more than 1000 μm, more preferably more than 1100 μm. By "minimum thickness" is meant the thickness of the thinnest point within the vertical course (C) of the interlayer. The thermoplastic interlayer is formed by at least one thermoplastic bonding interlayer with varying thickness, a so-called "wedge interlayer" with varying wedge angle, at least within a number of sections.

[0039] The thickness of the interlayer may be constant in the horizontal sections (i.e. in the sections that are approximately parallel to the upper and lower edges). In this case, the thickness profile is constant across the width of the laminated glass. However, the thickness may also vary within the horizontal sections. In this case, the thickness varies in the horizontal course as well as in the vertical course. The interlayer may be constructed by a single interlayer or, possibly, by a plurality of interlayers. In the latter case, at least one of the interlayers must be constructed to have a wedge angle. The interlayer may also be constructed as or may include a so-called "sound-absorbing interlayer" having a noise-damping effect. Such an interlayer is usually constructed of at least three layers, the central layer having a greater plasticity or a lower elasticity than the outer layers that surround it, for example as a result of the inclusion of a relatively higher amount of plasticizer. The interlayer may have two or more lower elastic layers that exhibit the mentioned noise-damping effect. While such an increase in the number of layers may result in a relatively better sound-absorbing performance, it also increases the possibility of air bubble generation. The advantage of having an intermediate layer greater than 900 μm thick becomes more evident when having two or more lower elastic layers.

[0040] The outer pane, inner pane, and thermoplastic interlayer may be clear and colorless, but may also be tinted or colored. In a preferred embodiment, the total light transmission through the laminated glass is greater than 70%. The term "total transmission" is based on the process for testing the light transmission of motor vehicle windows as defined by ECE-R43.

[0041] The windshield according to the invention may have a functional coating, such as, for example, an IR reflecting or absorbing coating, a UV reflecting or absorbing coating, a low emissivity coating, a heatable coating, etc. The functional coating may be arranged on the outer pane or on the inner pane. The functional coating is preferably arranged on the surface of the pane facing the thermoplastic interlayer, which is protected from corrosion and damage. The functional coating may also be arranged on an insert film in the interlayer, for example made of polyethylene terephthalate (PET).

[0042] The present invention is further realized by a method of manufacturing a laminated glass for a head-up display having an upper edge and a lower edge, the method comprising the steps of: a) a thermoplastic interlayer is provided, wherein the thickness of the thermoplastic interlayer in a course between two opposing edges (i.e., designated as a lower edge and an upper edge) varies at least within a plurality of sections, as described, for example, in WO 2017 / 153167; b) the thermoplastic intermediate layer referred to in step a) has a maximum wedge angle α of less than or equal to 0.4 mrad and a minimum thickness of 900 μm; c) a thermoplastic interlayer is placed between an inner pane made of glass having a thickness of less than 2 mm and an outer pane made of glass, the edges (between which the thickness may vary) being oriented so as to face the upper and lower edges; d) The inner and outer panes are joined together by lamination.

[0043] The preferred embodiments described above with reference to the laminated glazing apply mutatis mutandis to the method according to the invention.

[0044] A thermoplastic interlayer is provided as the interlayer. In a preferred embodiment, this is a conventional thermoplastic interlayer, in particular a PVB interlayer, having a substantially constant thickness (in the initial state), more particularly a wedge sound absorbing layer. The variable thickness with the wedge angle according to the invention is achieved by stretching the interlayer, in other words by applying a mechanical force through suitable tension. The small wedge angles according to the invention can be obtained by stretching, which is much more economical than producing a wedge interlayer by extrusion. Alternatively, the thermoplastic interlayer can be produced by extrusion using a wedge-shaped extrusion die.

[0045] In cases where bending of laminated glazing is required, the outer and inner panes are preferably subjected to a bending process prior to lamination. Preferably, the outer and inner panes are bent together in a coordinated manner (i.e. at the same time and by the same tool) since this provides an optimal matching of the pane shapes for the subsequent lamination. Typical temperatures for the glass bending process are, for example, 500°C to 700°C.

[0046] A thermoplastic interlayer is provided as the interlayer, and the wedge angle can be introduced into the interlayer by stretching an interlayer having a substantially constant thickness (in an initial state) or by extrusion using a wedge-shaped extrusion die.

[0047] Prior to lamination, the outer and inner panes are subjected below to a bending process corresponding to the calculated bending profile. Preferably, the outer and inner panes are bent together in a coordinated manner (i.e. at the same time and by the same tool) because this allows the pane shapes to be optimally matched for the subsequent lamination. Typical temperatures for the glass bending process are, for example, 500°C to 700°C.

[0048] The production of the laminated glazing is carried out by lamination by conventional methods known per se to the person skilled in the art, such as, for example, the autoclave method, the vacuum bag method, the vacuum ring method, the calendar method, the vacuum laminator, or combinations thereof. The joining of the outer and inner panes is conventionally carried out under the action of heat, vacuum and / or pressure.

[0049] Thus, the windshield and the projector are typically positioned relative to each other by mounting the windshield and the projector within the vehicle body, thereby creating a projection arrangement according to the invention.

[0050] Furthermore, the invention comprises the use of a projection arrangement according to the invention in a vehicle as a head-up display (HUD), preferably in an automotive vehicle, particularly preferably in an automobile.

[0051] The invention further includes the use of a laminated glazing according to the invention in an automotive vehicle, preferably in a passenger car, as a windshield that serves as a projection surface for a head-up display.

[0052] The present invention will now be described in detail with reference to the drawings and exemplary embodiments. The drawings are schematic representations and are not to scale. The drawings do not limit the present invention in any way. The accompanying drawings are as follows: [Brief description of the drawings]

[0053] [Figure 1] FIG. 1 is a plan view of one embodiment of a laminated glazing according to the present invention. [Diagram 2] 2 is a cross section through the laminated glazing of FIG. 1. [Diagram 3] represents the surface area (S) according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0054] Figures 1 and 2 depict details of a laminated glazing 10 according to the invention, having an outer pane 1 and an inner pane 2 interconnected via a thermoplastic interlayer 3. The laminated glazing is provided as a windshield for a motor vehicle equipped with a head-up display. In the installed position, the outer pane 1 faces towards the outside environment and the inner pane 2 faces towards the vehicle interior. In the installed position, the upper edge U of the laminated glazing points upwards towards the vehicle roof (roof edge) and the lower edge L points downwards towards the engine compartment (engine edge).

[0055] The outer pane 1 is made of soda-lime glass having a thickness of 2.1 mm or less. The inner pane 2 is also made of soda-lime glass and has a thickness of 1.6 mm or less. The thickness of the panes may typically range from 1.8 mm to 2.6 mm, and is customarily 2.1 mm for windshields.

[0056] The thickness of the interlayer 3 gradually increases in the vertical course from the lower edge L to the upper edge U. For the sake of clarity, the thickness has a non-linear thickness profile. The interlayer 3 is configured as a wedge sound absorbing interlayer made of PVB (typically three interlayers, but could be more). In the initial state, the interlayer was a PVB interlayer with a standard thickness of 0.38, 0.51, or 0.63 mm. In particular, the interlayer can be configured of more than two interlayers, at least one of which can be stretched to create a wedge angle. The initial thickness of a single interlayer can be 0.05, 0.1, 0.25, 0.38, 0.5, 0.63, 0.76, 0.81, or 1.05 mm. Two, three, or more sheets can be selected to create the desired wedge angle. The increased thickness was achieved in the interlayer by stretching, i.e., pulling, the lower edge L. The wedge angle α is about 0.2-0.4 mrad. Prior art composite glazing for HUDs has wedge angles in the range of about 0.5 mrad.

[0057] An example of a stretching method is described in WO2017153167.

[0058] In Fig. 1, the region F corresponds to the zone F where no enamel is present. The enamel M is conventionally applied along the (lateral and transverse) edges of the windscreen as shown and may extend up to the camera zone. The enamel M1 applied in the lower edge L of the windscreen 10 has an outer edge towards the lower edge of the windscreen 10 and an inner edge N1 in contact with the zone F where no enamel is present. The enamel M2 applied in the upper edge U of the windscreen 10 has an outer edge towards the upper edge U of the windscreen 10 and an inner edge N2 in contact with the zone F where no enamel is present.

[0059] FIG. 1 shows an imaginary horizontal line Z1 spaced 50 mm from the inner edge N1 of the enamel band M1 and another imaginary horizontal line Z2 spaced 50 mm from the inner edge N2 of the enamel band M2.

[0060] By "vertical course" C is meant the course between the upper edge U and the lower edge L, with the direction of the course being substantially perpendicular to the upper edge U. Since in a windshield the upper edge U may deviate significantly from a straight line, the vertical course C in the context of the present invention is more precisely expressed as being perpendicular to a connecting line between two corners of the upper edge U. The vertical course C passes through the HUD area H.

[0061] In Fig. 1, imaginary point P1 with values ​​of thickness TK1 and position D1 and imaginary point P2 with values ​​of thickness TK2 and position D2 are shown. Imaginary points P1 and P2 are from a series of n values ​​measured along a vertical course. Point P1 is located at the intersection between an imaginary horizontal line Z1 and a vertical course C. Point P2 is located at the intersection between an imaginary horizontal line Z2 and a vertical course C. Points P1 and P2 are separated by an imaginary vertical line d.

[0062] To calculate the surface area (S), n values ​​of thickness and position within the windshield were measured along an imaginary vertical line d separating points P1 and P2.

[0063] As shown in FIG. 3, the measured values ​​are plotted on a graph with the X-axis representing the position d of the measured points in the enamel-free zone F between the horizontal lines Z1 and Z2 along the vertical course (C). The position d is measured on the Y-axis from the thickness of the intermediate layer, more particularly the thermoplastic intermediate layer, for each measured point. A first value V1 is defined by the position (d(1)) and thickness (Tk(1)) of an imaginary point P1, P1 being obtained at a distance Y of 50 mm from the inner edge N' of the enamel M' placed in the lower part L of the windscreen along the imaginary line Z1, and a last value V2 is defined by the position (d(2)) and thickness (Tk(2)) of an imaginary point P2, P2 being obtained at a distance Y of 50 mm from the inner edge N'' of the enamel M'' placed in the upper part U of the windscreen along the imaginary line Z2, the thickness profile being defined by the series of n values ​​(V) mentioned above. According to this embodiment, the imaginary points P1 and P2 are separated by a distance d along a vertical course (C).

[0064] A line is drawn connecting the coordinates of point P1 and the coordinates of point P2.

[0065] According to the present invention, as shown in FIG. 3, the surface area S enclosed by the line connecting points P1 and P2 and the series of thickness values ​​measured at each location is 10,000 mm × It is over μm.

[0066] According to the invention, the thickness of the thermoplastic intermediate layer is greater than 900 μm, preferably greater than 1000 μm, more preferably greater than 1100 μm along the entire thickness in the vertical course (C). The intermediate layer preferably has a thickness of less than 2000 μm, preferably less than 1800 μm, more preferably less than 1400 μm. In a further preferred embodiment, the intermediate layer has a thickness of between 1100 μm and 1400 μm.

[0067] Due to the thickness profile according to the invention, the formation of air bubbles in the lamination process is therefore avoided.According to the invention, the interlayer is a wedge sound absorbing interlayer made from several layers of thermoplastic interlayers.

[0068] Also shown in Figure 1 is an area H of the laminated glazing, which corresponds to the HUD area. Within this area, an image is generated by a HUD projector 4. Using the configuration of the wedge shape 3 of the interlayer, the two images generated by reflection of the projector image on the two surfaces of the outer pane 1 and the inner pane 2 that are not facing the interlayer 3 are coincident with each other. As a result, distracting ghost images occur only to a small extent.

[0069] According to the invention, the thermoplastic interlayer is a wedge sound absorbing interlayer, such as those described in EP 1 800 855 or WO 2017 / 204121.

[0070] In fact, the present invention is particularly suitable when the thermoplastic interlayer is a wedge sound absorbing interlayer, since a relatively large foaming phenomenon occurs during the lamination process.

[0071] Figure 2 depicts the laminated glazing 10 of Figure 1 as part of a projection setup for a HUD. In addition to the laminated glazing 10, this setup has a projector 4 aimed at region H. The image perceived by an observer 5 (the driver of a motor vehicle) in region H (the HUD region) can be generated as a virtual image by the projector on the side of the laminated glazing 10 that is not facing it. The wedge angle (α) in region H results in the surfaces of the outer pane 1 and inner pane 2 being tilted relative to each other, which can be used to prevent ghost images.

[0072] According to one embodiment of the invention, the laminated glazing is formed by an outer pane 1 that is thicker than an inner pane 2 .

[0073] According to one embodiment of the present invention, the laminated glazing has a minimum bending radius of the glass that is less than 1000 mm.

[0074] In one embodiment of the present invention, the laminated glazing is a windshield onto which a head-up display image is projected, and the thickness profile of the interlayer creates a wedge angle within the projected area H that is greater than 0.2 mrad.

[0075] According to one embodiment of the present invention, the thermoplastic intermediate layer (3) is made of at least a first, a second and a third intermediate layer, which are stretched to have a certain thickness, thereby generating a first, a second and a third wedge angle.

[0076] The first, second and third intermediate layers are laminated together to produce a thickness of greater than 900 μm with a wedge angle resulting from the first, second and third angles.

[0077] The laminated interlayer is applied between two curved glass sheets and assembled by a degassing and autoclaving process to form the HUD sound absorbing windshield.

[0078] According to one embodiment of the invention, the sound absorbing layer is stretched: the thickness of the sound absorbing core layer at the upper edge at point P2 is 10% greater than the thickness of the sound absorbing core layer at the lower edge at point P1.

[0079] Thus, by reducing the thickness of the core layer, the number of air bubbles produced during the lamination process of the glass sheets that form the windshield can be reduced.

[0080] In one advantageous embodiment, the method according to the invention comprises a step of depositing a transparent layer, said transparent layer comprising said wedge layer.

[0081] In one advantageous embodiment, the wedge layer is a PVB layer. [Explanation of symbols]

[0082] (10) Windshield (1) Outer pane (2) Inner pane (3) Thermoplastic Interlayer (4) Projector (5) Observer / Vehicle Operator (U) Upper edge of windshield 1 (L) Bottom edge of windshield 1 (H) Stacked Glazing Area / HUD Area M. Enamel M1 Enamel applied on the lower edge of the windshield 10 M1 Enamel applied on the lower edge of the windshield 10 M2 Enamel applied on the upper edge of the windshield 10 N1 The inner edge of the lower edge of the applied enamel M1 on the windshield 10 N2 the inner edge of the upper edge of the applied enamel M2 on the windshield 10 Z1 Imaginary horizontal line 50 mm away from the inner edge N1 of enamel M1 Z2 Imaginary horizontal line 50 mm away from the inner edge N2 of enamel M2 Y the distance between M' and the imaginary line with a maximum value of 50 mm α Wedge angle of middle layer 3 C. Vertical course between upper edge U and lower edge L F. Enamel-free zone P1 Imaginary point at the intersection of Z1 line and vertical course C P1 Imaginary point at the intersection of Z2 line and vertical course C d Imaginary vertical line between P1 and P2

Claims

1. A laminated glazing (10) for a head-up display (HUD), the glazing (10) having an upper edge (U) and a lower edge (L), the glazing (10) comprising: an outer pane (1) and an inner pane (2) joined together via a thermoplastic intermediate layer (3); a HUD area (H) in which a virtual image is generated by a HUD projector (4); Including, the glazing (10) is provided along its edges with strips of enamel (M), the strips of enamel (M1, M2) being respectively in the lower edge (L) and in the upper edge (U) of the glazing (10), the strips of enamel (M1, M2) each having an inner edge (N1, N2) in contact with a zone (F) where no enamel is present, The glazing (10) is imaginary horizontal lines (Z1, Z2) parallel to the lower and upper strips (M1, M2) of enamel respectively and spaced apart from the inner edges (N1, N2) of the enamel (M1, M2) by a distance Y equal to 50 mm; a vertical course (C) from the upper edge (U) and the lower edge (L), the vertical course (C) passing through the HUD area (H); an imaginary point P1 which is the intersection of a horizontal imaginary line (Z1) and a vertical course (C); a virtual point P2 which is an intersection of a horizontal virtual line (Z2) and a vertical course (C); Including, Imaginary points P1 and P2 are separated by an imaginary vertical line d along a vertical course (c) within an enamel-free zone (F) along a vertical course (V), the thickness of the interlayer has a monotonically increasing wedge angle (α) within the vertical course (c) between the imaginary points P1 and P2, the thickness at the P2 point exceeding the thickness at the P1 point, and the interlayer along the glazing has a minimum thickness of 900 μm between the imaginary points P1 and P2 in the enamel-free zone (F) area along the vertical course (c); the thickness profile of the intermediate layer in a vertical course (C) is defined by a series of n values ​​(V) defined by positions (d(n)) and thicknesses (Tk(n)) measured from imaginary points P1 and P2 along an imaginary line d separating the imaginary points P1 and P2 to calculate a surface area (S); The calculated surface area (S) is bounded by a line connecting a first value V1 defined by the position (d(1)) and thickness (Tk(1)) of a virtual point P1 and a last value V2 defined by the position (d(2)) and thickness (Tk(2)) of a virtual point P2 and a thickness profile defined by said series of n values ​​(V), and is greater than 10,000 mm x μm; Glazing.

2. 10. The laminated glazing of claim 1, wherein the laminated glazing is a windshield of an automotive vehicle.

3. 3. A laminated glazing according to claim 1 or 2, wherein the wedge angle (α) defined by P1 and P2 is between 0.05 mrad and 0.5 mrad.

4. 4. A laminated glazing according to any one of claims 1 to 3, wherein the outer pane (1) and the inner pane (2) comprise soda lime glass and have a thickness of 0.8 mm to 5 mm, preferably 1.4 mm to 2.5 mm, and the intermediate layer (4) comprises at least polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), or mixtures or copolymers or derivatives thereof, preferably PVB.

5. 5. A laminated glazing according to claim 1, wherein the interlayer (3) is configured as a noise-damping multi-layer interlayer.

6. 6. A laminated glazing according to claim 5, wherein the number of noise attenuation layers is two or more.

7. 6. A laminated glazing according to claim 5, wherein the thickness of the noise damping layer at the lower bottom and the thickness of the noise damping layer at the upper bottom differ by 10%.

8. 8. A laminated glazing according to any one of the preceding claims, wherein the outer pane (1) is thicker than the inner pane (2).

9. 9. A laminated glazing according to any one of the preceding claims, wherein the minimum bending radius of the glass is less than 1000 mm.

10. 10. The laminated glazing of claim 1, wherein the laminated glazing is a windshield onto which a head-up display image is projected, and the thickness profile of the interlayer creates a wedge angle of greater than 0.2 mrad within the projected area H.

11. A method for producing a laminated glazing according to any one of claims 1 to 10, comprising at least the following steps: a) a thermoplastic interlayer is provided, wherein the thickness of the thermoplastic interlayer in a course between two opposing edges (i.e., designated as a lower edge and an upper edge) varies within at least a plurality of sections; b) the thermoplastic intermediate layer mentioned in step a) has a maximum wedge angle α of less than or equal to 0.4 mrad and a minimum thickness of 900 μm; c) a thermoplastic interlayer is placed between an inner pane made of glass having a thickness of less than 2 mm and an outer pane made of glass, the edges of which are oriented opposite the upper and lower edges; d) The inner and outer panes are joined together by lamination.

12. 7. Use of a laminated glazing according to any one of claims 1 to 6 in a vehicle, preferably in an automobile, particularly preferably in an automobile, as a head-up display (HUD).

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