WO2021063660A1

WO2021063660A1 - Laminated safety glass pane for head-up displays

Info

Publication number: WO2021063660A1
Application number: PCT/EP2020/075632
Authority: WO
Inventors: Daniel Krekel
Original assignee: Saint-Gobain Glass France
Priority date: 2019-10-02
Filing date: 2020-09-14
Publication date: 2021-04-08
Also published as: CN112912786A; DE202020005672U1

Abstract

The invention relates to a laminated safety glass pane (1) comprising: a first glass pane (21), a second glass pane (22), with at least one of the two glass panes (21, 22) being wedge-shaped, and an intermediate layer (3), which is arranged between the first glass pane (21) and the second glass pane (22) and connects the two glass panes to one another at least in some sections, the intermediate layer (3) being formed from a thermoplastic polymer and having a wedge-shaped cross-section at least in some sections, the wedge-shaped cross-section of the intermediate layer (3) being produced from a flat film by stretching and being matched to the wedge angle of the at least one wedge-shaped glass pane (21, 22) to avoid secondary images in head-up displays generated by reflection and/or refraction at the surfaces of the glass panes (21, 22). The invention also relates to the use of the laminated safety glass pane and to a method for producing same.

Description

Laminated safety glass for head-up displays

The present invention relates to a laminated safety glass pane for head-up displays.

The present invention also relates to the use of the laminated safety glass pane.

Laminated glass panes (VGS) are used nowadays in many places, especially in vehicle construction. The term vehicle includes road vehicles, airplanes, ships, agricultural machines and also work equipment.

Laminated glass panes are also used in other areas. These include, for example, building glazing or information displays, e.g. in museums or as advertising displays. A laminated glass pane generally has two glass surfaces or panes that are laminated onto an intermediate layer. The disks themselves can have a curvature and are generally of constant thickness. The intermediate layer usually comprises a thermoplastic material, preferably polyvinyl butyral (PVB), of a predetermined thickness, e.g. 0.76 mm.

Since the laminated glass panes are often inclined with respect to a viewer, double images occur. These double images are due to the fact that incident light does not usually pass completely through both panes, but rather that at least part of the light is reflected and only then passes through the second pane.

These double images are particularly noticeable in the dark, especially with strong light sources, such as the headlights of an oncoming vehicle. These double images are extremely annoying and a security problem. Laminated glass panes are also often used as a head-up display (HUD) to display information. An image is projected onto the laminated glass panes by means of a projection device in order to display information in the field of view for the viewer. In the vehicle area, the projection device is arranged on the dashboard, for example, so that the projected image is reflected in the direction of the viewer on the closest glass surface of the laminated glass pane inclined towards the viewer (cf., for example, European patent EP 0 420 228 B1 or German patent application DE 10 2012 21 1 729 A 1).

Here, in turn, part of the light enters the laminated glass panes and is now, for example, reflected at the inner boundary layer of the glass surface and the intermediate layer that is further outward from the viewer and then exits the laminated glass pane in an offset manner. Here, too, a similar effect occurs, the effect of ghost images, in relation to the image to be displayed.

Up to now, attempts have been made to solve this problem of secondary images generated by reflection and / or refraction on the surfaces of the glass panes by arranging the surfaces of the panes no longer parallel, but at a fixed angle. This is achieved, for example, in that the intermediate layer is wedge-shaped with a continuously linear and / or non-linear increasing and / or decreasing thickness. In vehicle construction, the thickness is typically varied so that the smallest thickness is provided at the lower end of the laminated glass pane towards the engine compartment, while the thickness increases towards the roof.

Laminated glass panes of this type with a wedge-shaped intermediate layer and the optical laws on which they are based are known per se and are described, for example, in the international patent applications WO 2015/086234 A1 and WO 2015/086233 A1, the American patents US 8,451, 541 B2, US 7,060,343 B2, US 6,881, 472 B2, US 6,636,370 B2 and US 5,013,134 or the German published documents DE 10 2007 095 323 A1, DE 196 11 483 A1 and DE 195 35 053 A1. The German patent application DE 101 12 935 A1 discloses a pane arrangement, in particular for a motor vehicle side pane, which has at least one flat, optically transparent element that is curved in at least one plane. The flat element has a wedge shape in its surface plane, a wedge angle running in the direction of the plane spanned by a normal of the element and a line of sight of a vehicle occupant. Details about the manufacture of the wedge-shaped element do not emerge from the German patent application.

The required wedge angle course and the resulting thickness profile of the intermediate layer must be calculated separately for each pane shape.

In this context, the American patent application US 2019/0126593 A1 reveals a consideration that deals with the relationship between the wedge angles, provided that not only the intermediate layer is wedge-shaped, but also at least one of the two glass panes of the composite. Although the combination of at least two wedge-shaped components of the total of three components is examined here with regard to the suppression of secondary images generated by reflection and / or refraction on the surfaces of the glass panes in head-up displays, it is also shown that it is only the Areas outside the viewing area of the display.

Wedge sheets are typically made by extrusion using a wedge-shaped extrusion die. The production of a wedge film with a desired wedge angle, which depends, among other things, on the specific pane geometry and the projection arrangement of the head-up display, is very expensive and complex.

This and other documents also show that it is very difficult to precisely match the wedge angle for the display areas of head-up displays in the case of laminated glass panes. In addition to the particular at Vehicles usually inclined installation position of the laminated glass pane is added that the panes are also curved.

In this regard, the two Japanese publications JP 2018203608 A and WO 2019/156030 A1 disclose a laminated glass pane with a combination of two panes and a polymeric intermediate layer, one of the two glass panes and the intermediate layer each having a wedge-shaped cross section. The intermediate layer can be adapted to the curved shape of the glass panes by stretching. However, the two publications do not provide any information about the production of the wedge-shaped cross-section of the intermediate layer, which is introduced to avoid ghosting in head-up displays, or about its targeted adaptation to the wedge-shaped shape of the glass pane for this purpose.

The object of the present invention is therefore to provide a new laminated safety pane for head-up displays which, due to its special material selection, enables the wedge angle of the glass panes and the intermediate layer to be adjusted very finely and precisely in such a way that by reflection and / or refraction Sub images generated on the surfaces of the glass can be effectively suppressed. In addition, the production of the intermediate layer should be less expensive and more precise than with the usual extrusion processes.

These and other objects are achieved according to the proposal of the present invention by a laminated safety glass pane having the features of claim 1. Further advantageous embodiments of the invention are given by the features of the subclaims. The object is also achieved through the use of a laminated glass pane according to the invention according to claim 11.

The subject matter of the present invention relates to a laminated safety glass pane comprising: a first glass pane, a second glass pane, at least one of the two glass panes being wedge-shaped, and an intermediate layer which is arranged between the first glass pane and the second glass pane and the two glass panes together at least in sections connects. According to the invention, the intermediate layer is formed from a thermoplastic polymer and has at least some sections of a wedge-shaped cross-section, the wedge-shaped cross-section of the intermediate layer being produced from a flat film by stretching and with the wedge angle of the at least one wedge-shaped glass pane, in particular to avoid reflection and / or refraction on the surfaces of the glass panes generated secondary images in head-up displays.

The laminated safety glass pane of the present invention is used above all for areas with a head-up display to avoid secondary images and in particular ghost images generated by reflection and / or refraction on the surfaces of the glass panes. In addition to being used as a windbreak, rear or side window of a vehicle, uses in buildings or in information displays, for example devices or advertising display devices, are also possible.

The laminated safety glass pane is aligned in the respective installation situation so that an upper edge, two side edges and a lower edge of the safety glass pane can be defined. In the case of a vehicle windshield, for example, the lower edge faces the engine compartment, while the upper edge adjoins the vehicle roof.

The thickness of the intermediate layer is variable at least in sections in the vertical course between the upper edge and the lower edge of the laminated safety glass pane. "In sections" here means that the vertical course between upper edge and lower edge has at least one section in which the thickness of the intermediate layer changes depending on the location, i.e. the intermediate layer has a wedge angle. The thickness of the intermediate layer is variable at least in the HUD area. The thickness can, however, also change in several sections or increase essentially steadily in the entire vertical course, for example from the lower edge to the upper edge. The vertical course denotes the course between the upper edge and the lower edge with the course direction essentially perpendicular to the upper edge If the upper edge of laminated safety glass panes can deviate significantly from a straight line, the vertical course in the sense of the invention, expressed more precisely, is aligned perpendicular to a (straight) connecting line between the corners of the upper edge. The intermediate layer has, at least in sections, a finite wedge angle, that is to say a wedge angle greater than 0 °, namely in the section in which the thickness is variable. The angle between the two surfaces of the intermediate layer is referred to as the wedge angle. If the wedge angle is not constant, the tangents on the surfaces are to be used to measure it at a point.

The invention thus enables the use of thermoplastic films with only small wedge angles, which can be produced more cheaply and precisely in the usual production process of a laminated glass pane than films with larger wedge angles. Such films can namely be obtained by stretching a film of constant thickness instead of by extrusion. The person skilled in the art can also subsequently recognize whether a wedge angle is formed by stretching or by extrusion, in particular from the typical thickness profile in the vicinity of the lower edge and / or upper edge.

Modern automobiles are increasingly being equipped with so-called head-up displays (HUDs). With a projector, for example in the area of the dashboard or in the roof area, images are projected onto the windshield, reflected there and perceived by the driver as a virtual image (seen from him) behind the windshield. In this way, important information can be projected into the driver's field of vision, for example the current speed, navigation or warning information that the driver can perceive without having to take his eyes off the road. In this way, head-up displays can make a significant contribution to increasing road safety.

In the case of the heads-up displays described above, the problem arises that the projector image is reflected on the various surfaces of the windshield. As a result, the driver not only perceives the desired main image, but also a slightly offset, usually lower-intensity secondary image. The latter will commonly referred to as ghosting. As is known, this problem is solved in that the reflective surfaces are arranged at a deliberately chosen angle to one another, so that the main image and the ghost image are superimposed, as a result of which the ghost image is no longer disruptive. With conventional laminated glasses for head-up displays, the angle is typically around 0.5 mrad.

Windshields consist of two panes of glass, which are laminated together with a thermoplastic film. If the surfaces of the glass panes are to be arranged at an angle as described, it is customary to use a thermoplastic film with a non-constant thickness. One also speaks of a wedge-shaped film or wedge film. The angle between the two surfaces of the film is called the wedge angle. Laminated glasses for head-up displays with wedge foils are known, for example, from EP1800855B1 or EP1880243A2.

The shift of the ghost image in relation to the main image, and thus its conspicuousness, depends essentially on the distance between the two reflective surfaces. The ghost image can therefore also be reduced by reducing the layer thicknesses of the components of the windshield.

The invention enables the use of very small wedge angles of the intermediate layer, which in combination and in accordance with the invention with at least one wedge-shaped glass pane reduces the problem of secondary images in the projection generated by reflection and / or refraction on the surfaces of the glass panes. This is another important advantage of the invention. The coordination of the wedge angle of the lens or glasses and that of the intermediate layer can be done in a simple manner in very small increments with the intermediate layer produced according to the invention by stretching and allows an optimization of the coordination of the different wedge angles of the components joined to the composite pane, which was previously impossible. In one embodiment of the invention, the intermediate layer produced from a flat film by stretching has a linear or non-linear profile of the at least partially wedge-shaped cross section.

In other words, the wedge angle can be constant in the vertical course, which leads to a linear change in the thickness of the intermediate layer, the thickness typically and preferably increasing from bottom to top. The direction indication "from bottom to top" denotes the direction from lower edge to upper edge.

However, there can also be more complex thickness profiles in which the wedge angle is variable from bottom to top (that is, it is location-dependent in the vertical course), linear or non-linear.

The thickness of the intermediate layer can be constant in horizontal sections (that is, sections approximately parallel to the upper edge and lower edge). Then the thickness profile is constant across the width of the laminated glass. However, the thickness can also be variable in horizontal sections. Then the thickness is variable not only in the vertical, but also in the horizontal course. The intermediate layer is formed by at least one thermoplastic film. According to the invention, the wedge angle is produced by stretching in the film. The wedge-shaped film is not extruded, but originally provided as a conventional film with an essentially constant thickness and shaped by stretching in such a way that it has the desired and, according to the invention, with the wedge angle (s) of the glass pane (s) to avoid reflection and / or refraction on the surfaces of the glass panes generated secondary images has coordinated wedge angle. This can be integrated into a conventional production process of a laminated glass pane in a simpler and more cost-effective manner than production by extrusion. The person skilled in the art can also subsequently recognize whether a wedge angle is formed by stretching or by extrusion, in particular from the typical thickness profile in the vicinity of the lower edge and / or upper edge.

With a suitable design of the laminated safety glass pane, significantly smaller wedge angles of the intermediate layer can be sufficient. In a preferred embodiment, the maximum wedge angle of the intermediate layer is 0.1 mrad. The smaller the wedge angle of the intermediate layer, the finer the inventive Coordination of the combination with the at least one wedge-shaped glass pane take place. A significant simplification can be achieved in the production process in that the present invention makes it possible to use wedge-shaped glass panes with standardized wedge angles and to fine-tune the respective head-up display via the intermediate layer, which is easy to manufacture even with small wedge angles by stretching . This leads to a very efficient and, above all, very good quality laminated safety glass pane in relation to the individual requirements of the head-up display.

The thicknesses of the first glass pane and the second glass pane can in principle be freely selected within the framework of the values customary in the field. For conventional windshields, thicknesses of the individual panes in the range 1 mm to 5 mm, in particular 1.2 mm to 3 mm, are common. The wedge angles according to the invention can thus be implemented without any problems. The individual disks each advantageously have a thickness that is a maximum of 5 mm, preferably a maximum of 3 mm. Standard slice thicknesses are, for example, 2.1 mm or 1.6 mm. Preferred thicknesses for the first glass pane, which when used as a windshield, for example, can form the outer pane, and for the second glass pane, which in this case forms the inner pane, are in the range from 1.2 mm to 2.6 mm, particularly preferably from 1.4mm to 2.1mm. In a preferred embodiment, the thickness of the first disk and the second disk are at most 2.6 mm, particularly preferably at most 2.1 mm, because this advantageously requires small wedge angles.

In a further preferred embodiment, at least one of the individual panes of the laminated glass pane has a smaller thickness. In addition to the weight saving, this has the advantage that an even smaller wedge angle is required to compensate for the secondary image generated by reflection and / or refraction on the surfaces of the glass panes, because the reflective surfaces are closer to one another. As a result, the main image and the secondary image are shifted less strongly from one another, so that they can be brought into congruence with a smaller wedge angle. The second pane of glass preferably has a thickness of less than 1.2 mm. The first glass pane is preferably thicker than the second glass pane, as a result of which despite the lower material thickness, sufficient stability of the laminated glass pane is achieved. The thickness of the second glass pane is particularly preferably from 0.3 mm to 1.1 mm, very particularly preferably from 0.5 mm to 0.9 mm and in particular from 0.6 mm to 0.8 mm.

The first glass pane can have a thickness in the conventional range for laminated glasses, in particular in the range from 2.1 mm to 3.0 mm, for example 2.1 mm or 2.6 mm. In a particularly advantageous embodiment, the first glass pane is also a thinner pane and has a thickness of less than 2.1 mm. This increases the advantages mentioned above.

The thickness of the first glass pane is preferably from 1.2 mm to 2.0 mm, particularly preferably from 1.4 mm to 1.8 mm, very particularly preferably from 1.5 mm to 1.7 mm. With these thicknesses, the laminated glasses are sufficiently stable to be used as vehicle glazing. An asymmetrical combination of a thicker first pane of glass and a thinner second pane of glass has proven itself to increase stone chip resistance and breaking strength. The two panes of glass can be non-toughened panes. Alternatively, however, the thin second glass pane can be a chemically toughened pane. During chemical toughening, the chemical composition of the glass in the area of the surface is changed by ion exchange. In particular, the thicker first glass sheet is a non-toughened sheet and the thinner second glass sheet is a chemically toughened sheet.

The two panes of glass are preferably made of glass, particularly preferably of soda-lime glass, which has proven itself for window glasses. The panes can also consist of other types of glass, for example borosilicate glass or aluminosilicate glass. In principle, the panes can alternatively be made of plastic, in particular polycarbonate or PMMA. The first pane of glass preferably contains soda-lime glass, the second pane of soda-lime glass or aluminosilicate glass. Particularly preferably, the first glass pane consists of non-toughened soda-lime glass and the second glass pane either also consists of non-toughened soda-lime glass or of chemically toughened aluminosilicate glass. Aluminosilicate can be chemically toughened more effectively than soda-lime glass. The two panes and the thermoplastic intermediate layer can be clear and colorless, but also tinted or colored. In a preferred embodiment, the total transmission through the laminated glass is greater than 70%, in particular if the laminated glass is a windshield. The term overall transmission refers to the procedure for testing the light transmission of motor vehicle windows specified by ECE-R 43, Annex 3, Section 9.1.

In addition to the vertical curvature, the windshield is also characterized by a horizontal curvature. However, this has a subordinate influence on the ghosting problem and is therefore not essential to the invention. It can be chosen according to the standard of the subject. The laminated safety glass pane can in principle also be flat (that is to say have an infinite vertical and horizontal radius of curvature), for example if it is intended as a pane for buses, trains or tractors.

In one embodiment of the invention, both glass panes are wedge-shaped. As a result, smaller wedge angles can be provided for the disks, which can be produced more easily in very good quality than those with very large wedge angles. In addition, in the perception of the user in this embodiment, a better quality of the head-up display can result from the fact that, due to the production, the two wedge-shaped glasses can have horizontal float lines, especially as float glasses. The rectification of the float lines of the two wedge-shaped glass panes can produce a better quality perception of the head-up display on the laminated safety glass pane for users, in contrast to the combination of a wedge-shaped float glass with horizontal and a non-wedge-shaped glass with standard vertical float lines. Test subjects have reported that they perceived to a certain extent less distortion in this embodiment of the invention with two wedge-shaped sheets of glass and an intermediate layer made by stretching than with one Combination of the intermediate layer with a wedge-shaped and a non-wedge-shaped pane of glass.

In a preferred embodiment of the laminated safety glass pane according to the invention, the resulting wedge angle of the laminated safety glass pane results from the addition of the wedge angles of the two glass panes and the wedge angle of the intermediate layer and is in a range between 0.2 and 0.75 mrad, preferably between 0.3 and 0, 7 mrad, and in particular between 0.35 and 0.65 mrad.

For example, the combinations of wedge angle values roughly summarized in the following table can be implemented in a laminated safety glass pane according to the invention:

In a further embodiment of the laminated safety glass pane according to the invention, the intermediate layer has a width of 0.25 m to 4.0 m and a thickness of 100 μm to 2000 μm.

The intermediate layer preferably has a minimum thickness of 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, very particularly preferably from 0.5 mm to 0.9 mm. The minimum thickness is the thickness at the thinnest point of the intermediate layer designated. Laminated glasses with thinner intermediate layers often have too little stability to be used as a vehicle window. Thermoplastic foils, especially PVB foils, are sold with a standard thickness of 0.76 mm. Wedge angles according to the invention can advantageously be introduced from these films by stretching. Since the wedge angles according to the invention are very small, the film is not locally thinned to such an extent that problems arise with the stability of the laminated glass.

The intermediate layer is made of a flat, transparent plastic film by stretching made of plastics selected from the group consisting of polyvinyl butyral (PVB), ethylene vinyl acetal (EVA), polyethylene terephthalate (PET), polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride, polyacetal resins, casting resins, fluorinated ethylene-propylene copolymers, polyvinyl fluoride, ethylene-tetrafluoroethylene copolymers and copolymers and mixtures thereof. In a preferred embodiment, the intermediate layer is formed from a PVB film.

The intermediate layer can be formed by a single film or by more than one film. In the latter case, at least one of the foils must be designed with the wedge angle. The intermediate layer can also be formed from what is known as an acoustic film, which has a noise-dampening effect. Such films typically consist of at least three layers, the middle layer having a higher plasticity or elasticity than the outer layers surrounding it, for example as a result of a higher proportion of plasticizers. The use of such a sound-damping, multilayer film is preferably used to improve the acoustic comfort. This is particularly advantageous if one of the two glass panes is designed with a small thickness and as a result is less able to shield noise.

Equally, one or both of the wedge-shaped glass panes in the laminated safety glass pane of the present invention can have a certain greater noise-dampening effect than non-wedge-shaped glasses, since the increase in their thickness due to the wedge-shape also achieves greater noise insulation. This increases the user's perception of comfort. In a further embodiment of the invention, the profile of the wedge angle of the intermediate layer is constant and the wedge angle is in a range between 0.01 and 0.5 mrad, preferably between 0.05 and 0.35 mrad.

These comparatively small wedge angles can be produced particularly well by stretching a flat film. The production of constant wedge angles is associated with less effort than the production of variable wedge angles. With small wedge angles of the intermediate layer, according to the invention, a very fine coordination with the wedge angle or angles of the glass pane or panes is possible, which on the one hand minimizes the formation of ghost images and on the other hand effectively compensates for such occurrences to produce a clear display image. The wedge-shaped glass panes of which the wedge angle is not completely sufficient to minimize the occurrence of ghost images can also be used through the targeted selection of the wedge-shaped intermediate layer according to the invention. In this way, considerable savings can be achieved in the production of laminated safety glass panes for head-up displays, since the glass panes and the wedge-shaped intermediate layers can be prefabricated in large numbers and can be combined as required.

In a preferred embodiment, both glass panes are wedge-shaped and the intermediate layer produced by stretching is also wedge-shaped in such a way that the resulting laminated safety glass pane suppresses ghost images of a head-up display.

The coordination of the wedge angles of the components of the laminated safety glass pane can be carried out by experiments as a function of the head-up display used and its position and is generally known to the person skilled in the art. With the use of the wedge-shaped intermediate layer produced by stretching and the provision of a wedge shape for each of the three components, very precise fine-tuning can be made possible, which achieves an effective suppression of ghost images while at the same time being simple and inexpensive to manufacture. The invention also comprises a method for producing a laminated safety glass pane according to the invention, comprising the following steps:

Obtaining a first glass pane and a second glass pane, the first and / or the second glass pane being wedge-shaped, providing a flat film made of a thermoplastic polymer and stretching the film in such a way that a wedge-shaped cross section is produced at least in sections, thereby producing an intermediate layer,

- Placement of the intermediate layer on the first glass pane, the thermoplastic intermediate layer at least in sections the produced by stretching and, in particular to avoid secondary images generated by reflection and / or refraction on the surfaces of the glass panes in a head-up display, with the wedge angle of at least a wedge-shaped glass pane has a matching wedge shape,

- placing the second pane of glass on the thermoplastic intermediate layer, and

Joining the thermoplastic intermediate layer with the first and the second glass pane to form a laminated safety glass pane.

A laminated safety glass pane can thus be produced in a tried and tested manner in that the intermediate layer, which is at least partially wedge-shaped by stretching, is connected to the first and second glass panes. Because of the small wedge angles possible according to the invention for the glass panes and above all for the intermediate layer, it is possible to carry out the joining process with the tried and tested systems, since, for example, the holding devices do not have to be specially adapted.

An important advantage of the method according to the invention is that, depending on the head-up display, different wedge angles of the laminated safety glass pane have to be set. The method according to the invention enables this particular adaptation to be carried out quickly and efficiently in the To implement production. For example, one or more panes of glass with standardized wedge angles (such as 0.1 mrad, 0.2 mrad, 0.3 mrad, 0.4 mrad, 0.5 mrad, 0.6 mrad, 0.7 mrad etc.) ) and the adaptation of the required wedge angle of the pane as a whole to the respective head-up display can be done by stretching the film or films of the intermediate layer. In this way, a modular principle can be built that still has the necessary flexibility to adapt to many different display requirements. It is advantageously also possible here to adapt both the extent of the wedge angle and its position or its change in a specific section of the pane by stretching the film or films.

In principle, it is also possible to initially only connect a first glass pane to the thermoplastic intermediate layer after it has been applied and only then to apply the second glass pane and to connect it to the thermoplastic intermediate layer that has been pre-connected to the first glass pane.

In one embodiment of the invention, the wedge angle of the intermediate layer before joining with the two glass panes is smaller than in the resulting composite and a related correction factor is taken into account when the wedge-shaped intermediate layer is produced by stretching.

In some methods for joining and connecting the glass panes and the intermediate layer, it can happen that the wedge angle of the intermediate layer is changed by pressing the last glass pane or by pressing the composite. In general, there is an increase in the wedge angle. According to the invention, this can already be taken into account by the choice of the wedge angle of the intermediate layer, for example in such a way that a correction value for the changes in the wedge angle occurring when connecting the components to form a laminated glass is subtracted from the value to be achieved. Alternatively, a correction value can also be taken into account when a reduction in the original wedge value of the intermediate layer occurs in such a way that it is added to the target wedge value for the intermediate layer. In an alternative embodiment of the invention, the intermediate layer is produced from a wedge-shaped film by stretching in such a way that the wedge angle of the film after stretching is greater than it was before stretching. In this case, not a flat film is used as the starting material for the intermediate layer, but rather one that is already wedge-shaped. This wedge-shaped film is processed by stretching in such a way that it has a larger wedge angle than before the stretching. As a result, the manufacture of the laminated safety glass pane can be made more variable.

In a further embodiment of the method according to the invention, the thermoplastic intermediate layer is connected to the first and the second glass pane in an autoclave and under the action of heat and pressure.

Of course, the thermoplastic intermediate layer produced by stretching can not only be used in an autoclave process, but can also be used, for example, with a vacuum-thermo-open process or similar autoclave-free processes such as in a process with pre-lamination.

The invention also includes the use of a laminated safety glass pane as a vehicle window, in particular as a windshield, as building glazing, as information displays, or as advertising displays. Vehicles are not only understood to mean automobiles but also other land-based and water-based vehicles such as trains, agricultural machinery, work machines, trucks and all types of boats and ships.

The laminated safety glass pane according to the invention can have a functional coating for at least one of the aforementioned uses, for example an IR-reflecting or absorbing coating, a UV-reflecting or absorbing coating, a coloring coating, a coating of low emissivity, a heatable coating, a coating with antenna function, a splinter-binding coating or a coating for shielding against electromagnetic radiation. The functional coating can be arranged on a surface of the first glass pane or the second glass pane, or on an insert film in the intermediate layer, which consists for example of polyethylene terephthalate (PET). It goes without saying that the features mentioned above and explained in more detail below can be used not only in the specified combinations and configurations but also in other combinations and configurations or on their own without departing from the scope of the invention. Embodiments of the present invention are described by way of example with reference to the attached drawings, in which:

1 shows a schematic representation of a disk according to the invention of an embodiment of the invention in a cross-sectional view, and

2 shows a schematic representation of a disk according to the invention of a further embodiment of the invention in a cross-sectional view.

The figures serve for basic illustration and are not reproduced true to scale or proportionally correctly in their schematic representation.

A schematic cross section of a laminated safety glass pane 1 according to the invention is shown in FIG. The laminated safety glass pane 1 comprises a first pane 21 and a second pane 22, both of which are made, for example, from float glass. The individual disks 21 and 22 each have a wedge-shaped profile with a constant wedge angle of, for example, 0.1 mrad, 0.2 mrad, 0.3 mrad, 0.4 mrad, 0.5 mrad, 0.6 mrad or 0, 7 mrad. Any desired wedge angle values between those mentioned above can of course also be provided. The wedge-shaped profile of the thicknesses of the individual disks 21 and 22 is oriented in such a way that the thickness increases constantly starting from the lower edge of the disk 21, 22 in the assembly orientation to the upper edge of the disk 21, 22. An intermediate layer 3 made of a thermoplastic polymer is arranged between the two panes 21 and 22 and connects the two panes at least in sections. According to the invention, the intermediate layer 3 is produced from a flat film by stretching in such a way that it has a wedge-shaped cross section. In other words, a change in thickness was produced in the intermediate layer by stretching a flat film before it was joined to the two glass panes 21 and 22. In the example shown, the change in thickness of the intermediate layer 3, like the change in thickness of the glass panes, is constant and, when the pane is installed, increases from the lower edge to the upper edge of the laminated safety glass pane. Typical wedge angles for the intermediate layer alone are in a range between 0.01 and 0.5 mrad, preferably between 0.05 and 0.35 mrad. They are selected in coordination with the wedge angles of the glass panes 21 and 22 in such a way that the occurrence of ghost images when projecting a head-up display is reduced or avoided entirely.

The intermediate layer 3 preferably has a minimum thickness of 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, very particularly preferably from 0.5 mm to 0.9 mm. The minimum thickness is the thickness at the thinnest point of the intermediate layer. Laminated glasses with thinner intermediate layers often have too little stability to be used as a vehicle window. Thermoplastic foils, especially PVB foils, are sold with a standard thickness of 0.76 mm. Wedge angles according to the invention can advantageously be introduced from these films by stretching. Since the wedge angles according to the invention are very small, the film is not locally thinned to such an extent that problems arise with the stability of the laminated glass.

The intermediate layer is made of a flat, transparent plastic film by stretching made of plastics selected from the group consisting of polyvinyl butyral (PVB), ethylene vinyl acetal (EVA), polyethylene terephthalate (PET), polyurethane (PU), polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride, polyacetal resins, casting resins, fluorinated ethylene-propylene copolymers, polyvinyl fluoride, ethylene-tetrafluoroethylene copolymers and copolymers and mixtures thereof. The In a preferred embodiment, the intermediate layer is formed from a PVB film.

The intermediate layer can be formed by a single film or by more than one film. In the latter case, at least one of the foils must be designed with the wedge angle.

In Figure 2, a laminated glass pane 1 according to the invention is shown schematically in a further embodiment of the invention in a cross-sectional view. As in FIG. 1, the laminated safety glass pane 1 comprises a first pane 21 and a second pane 22, both of which are made, for example, from float glass. The disks 21 and 22 are connected to one another at least in sections with an intermediate layer 3. According to the invention, the intermediate layer 3 is produced from a flat film by stretching in such a way that it has a wedge-shaped cross section. In other words, a change in thickness was produced in the intermediate layer by stretching a flat film before it was joined to the two glass panes 21 and 22. In the example shown, the change in thickness of the intermediate layer 3 is constant and, when the pane is installed, increases in size from the lower edge to the upper edge of the laminated safety glass pane 1. The wedge angle of the intermediate layer produced by stretching is, according to the invention, coordinated with the wedge angle or angles of the glass pane (s) in such a way that the emergence of secondary images generated by reflection and / or refraction on the surfaces of the glass panes 21, 22 in head-up displays is effectively avoided. Typical wedge angles for the intermediate layer alone are in a range between 0.01 and 0.5 mrad, preferably between 0.05 and 0.35 mrad. In contrast to the embodiment shown in FIG. 1, only the second pane 22 has a wedge-shaped profile, while the first glass pane 21 in this embodiment has a constant thickness, ie no wedge angle. The wedge-shaped course of the second glass pane has a constant wedge angle of, for example, 0.1 mrad, 0.2 mrad, 0.3 mrad, 0.4 mrad, 0.5 mrad, 0.6 mrad or 0.7 mrad. The wedge angle of the intermediate layer 3 is selected in coordination with the wedge angle of the glass pane 22 in such a way that secondary images generated by reflection and / or refraction on the surfaces of the glass panes 21, 22 occur when a head-up display is projected onto the laminated safety glass pane 1 according to the invention is greatly reduced or avoided entirely.

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List of reference symbols

1 laminated safety glass pane

21 first glass pane 22 second glass pane

3 intermediate layer

Claims

1. Laminated safety glass pane (1) comprising: a first glass pane (21), a second glass pane (22), at least one of the two glass panes (21, 22) being wedge-shaped, and an intermediate layer (3) which is sandwiched between the first glass pane ( 21) and the second glass pane (22) and connects the two glass panes to one another at least in sections, the intermediate layer (3) being formed from a thermoplastic polymer and at least in sections having a wedge-shaped cross section, characterized in that the wedge-shaped cross section of the intermediate layer ( 3) is made from a flat film by stretching and is matched to the wedge angle of the at least one wedge-shaped glass pane (21, 22).

2. Laminated safety glass pane (1) according to claim 1, wherein the intermediate layer (3) produced from a flat film by stretching has a constant, linear or non-linear course of the at least partially wedge-shaped cross section.

3. Laminated safety glass pane (1) according to one of claims 1 or 2, wherein both glass panes (21, 22) are wedge-shaped.

4. Laminated glass pane (1) according to one of the preceding claims, wherein the resulting wedge angle of the laminated safety glass pane (1) results from the addition of the wedge angle of the two glass panes (21, 22) and the wedge angle of the intermediate layer (3) and in a range between 0 , 2 and 0.75 mrad, preferably between 0.3 and 0.7 mrad, and in particular between 0.35 and 0.65 mrad.

5. Laminated safety glass pane (1) according to one of the preceding claims, wherein the course of the wedge angle of the intermediate layer (3) is constant and the wedge angle is in a range between 0.01 and 0.5 mrad, preferably between 0.05 and 0.35 mrad.

6. Laminated safety glass pane (1) according to one of the preceding claims, wherein the intermediate layer (3) is made of a flat, transparent plastic film by stretching from plastics selected from the group consisting of polyvinyl butyral (PVB), ethylene vinyl acetal (EVA), polyethylene terephthalate ( PET), polyurethane (PU), polypropylene (PP),

Polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate (PMMA), polyvinyl chloride, polyacetal resins, casting resins, fluorinated ethylene-propylene copolymers, polyvinyl fluoride, ethylene-tetrafluoroethylene copolymers and copolymers and mixtures thereof.

7. Laminated safety glass pane (1) according to one of the preceding claims, wherein the intermediate layer (3) has a width of 0.25 m to 4.0 m and a thickness of 100 μm to 2000 μm.

8. Laminated safety glass pane (1) according to one of the preceding claims, wherein both glass panes (21, 22) are wedge-shaped and the intermediate layer (3) produced by stretching is additionally wedge-shaped such that the resulting laminated safety glass pane 1 by reflection and / or refraction at the Additional images of a head-up display generated on the surfaces of the glass panes (21, 22) are suppressed.

9. A method for producing a laminated safety glass pane (1) according to any one of claims 1 to 8, comprising the following steps:

Obtaining a first glass pane (21) and a second glass pane (22), wherein the first and / or the second glass pane (21, 22) is wedge-shaped,

Providing a flat film made of a thermoplastic polymer and stretching the film in such a way that a wedge-shaped cross section is produced at least in sections, thereby producing an intermediate layer (3),

- Placing the intermediate layer (3) on the first glass pane (21), the thermoplastic intermediate layer (3) at least in sections through the Has a wedge shape produced by stretching and coordinated with the wedge angle of the at least one wedge-shaped glass pane (21, 22),

- placing the second glass pane (22) on the thermoplastic intermediate layer (3), and

Joining the thermoplastic intermediate layer (3) with the first (21) and the second glass pane (22) to form a laminated safety glass pane (1).

10. The method according to claim 9, wherein the wedge angle of the intermediate layer (3) before joining with the two glass panes (21, 22) is smaller than in the resulting composite and a related correction factor in the production of the wedge-shaped intermediate layer (3) by stretching and is taken into account in the coordination with the wedge angle of the at least one wedge-shaped glass pane (21, 22) to avoid secondary images generated by reflection and / or refraction on the surfaces of the glass panes (21, 22) in head-up displays.

11. The method according to any one of the preceding claims 9 or 10, wherein the intermediate layer (3) is made from a wedge-shaped film by stretching in such a way that the wedge angle of the film is greater after stretching than it was before stretching.

12. The method according to any one of the preceding claims 9 or 11, wherein the joining of the thermoplastic intermediate layer (3) with the first (21) and the second glass pane (22) takes place in the autoclave and under the action of heat and pressure.

13. Use of a laminated safety glass pane (1) as a vehicle window, in particular as a windshield, as building glazing, as information displays, or as advertising displays.