WO2023186715A1

WO2023186715A1 - Head-up display for a vehicle window

Info

Publication number: WO2023186715A1
Application number: PCT/EP2023/057587
Authority: WO
Inventors: Julian GREVERATH; Michele CAPPUCCILLI; Martin Arndt; Stefan Hertel
Original assignee: Saint-Gobain Glass France
Priority date: 2022-03-30
Filing date: 2023-03-24
Publication date: 2023-10-05
Also published as: CN117157572A

Abstract

The invention relates to a head-up display (100) for a vehicle window (1) with an outer side (I) facing an external environment (13) and an inner side (IV) facing a vehicle interior in the installed state, comprising: at least one transparent panel (2, 3); at least one masking strip (5) in an edge region (11) of the panel (2, 3); at least one reflective layer (9), in particular applied in the printing process, for reflecting light, and arranged in the region of the masking strip (5) on the vehicle-interior-side of the masking strip; at least one image display device (8) associated with the reflective layer (9) and having an image display directed towards the reflective layer (9), wherein the projected image (14) thereof is reflected into the vehicle interior (12) by the reflective layer (9), wherein the image display device (8) is curved in a horizontal direction when viewed from above.

Description

HEAD-UP DISPLAY FOR A VEHICLE WINDOW

The invention relates to a head-up display for a vehicle window, in particular a black print display with at least one image display device, a method for its production and use, as well as a head-up display with the vehicle window and a correspondingly equipped vehicle.

Vehicles, especially passenger cars (cars), are increasingly being equipped with so-called head-up displays (HUDs), as are known, for example, from DE 10 2009 020824 A1. Head-up displays are intended to display image information for a viewer or driver. Using a projector as an image generator, 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 behind the windshield. Important information can be projected into the driver's field of vision, such as the current driving speed, navigation or warning information, which the driver can perceive without having to take his eyes off the road. Head-up displays can make a significant contribution to increasing road safety.

Vehicle windshields usually consist of two panes of glass, which are laminated together using at least one thermoplastic film. The head-up display described above has the problem that the projector image is reflected on both surfaces of the windshield. As a result, the driver not only perceives the desired main image, which is caused by the reflection on the interior surface of the windshield (primary reflection). The driver also perceives a slightly offset, usually less intense secondary image, which is caused by the reflection on the outside surface of the windshield (secondary reflection). This problem is usually solved by arranging the reflecting surfaces at a specifically selected angle to one another so that the main image and secondary image are superimposed, so that the secondary image is no longer distracting.

Vehicle windows, in particular windshields, usually have, in addition to the transparent viewing area, an opaque masking area with an opaque layer through which no viewing is possible. The masking area is typically arranged in a peripheral edge area of the windshield and surrounds the viewing area. The opaque masking area is primarily used to bond the windshield to protect the adhesive used with the vehicle body from UV radiation. If the composite pane is equipped with electrical functions (for example a heating function), the necessary electrical connections can also be concealed with the masking area. The masking area is typically formed by a black masking print on the surface of the outer pane facing the intermediate layer.

It is also known to provide vehicle windows with transparent, electrically conductive coatings. For example, these coatings can act as IR reflective coatings to reduce heating of the vehicle interior and thereby improve thermal comfort, or can be used as heatable coatings by connecting them to a voltage source so that a current flows through the coating. In connection with head-up displays, windshields with conductive coatings inside the laminated glass have the problem that the conductive coating forms a further reflective interface for the projector image. This also leads to an undesirable secondary image.

When designing a head-up display, care must also be taken to ensure that the projector has a correspondingly high output so that the projected image, especially when exposed to sunlight, has sufficient brightness and can be easily seen by the viewer. This requires a certain size of the projector and is associated with a corresponding power consumption.

For example, power requirements can be reduced by increasing the contrast of the reflected image. This makes it possible to create a virtual image even in the masking area, basically using the same principle as a HUD. The masking area is also irradiated by a projector and the light is reflected there, creating a display for the driver. For example, information that was previously displayed in the dashboard area, such as time, driving speed, engine speed or information from a navigation system, or even the image from a rear-facing camera, which replaces the classic exterior mirrors or rear-view mirrors, can be displayed directly in a practical and aesthetically appealing way of the windshield, for example in the portion of the masking area that borders the lower edge of the windshield. A projection arrangement of this type is known, for example, from DE102009020824A1. Rectangular flat image display devices are commonly used to illuminate the display area in projection arrays. This has the disadvantage that the contour of the projected image does not match the reflective layer of the vehicle window because this is usually curved in the horizontal and vertical directions. This leads to a virtual image that changes in some areas, which appears inconsistent and not homogeneous to the viewer. For this reason, depending on the design of the system, image cropping and/or image distortion may be required at the top or bottom of the displayed image. This in turn leads to a reduction in the size of the projected image. The reduction in image size can be compensated for by using an enlarged image display device with higher power consumption. However, this increases the material and energy costs and there is an increased space requirement for the image display device.

A disadvantage of placing rectangular display elements in the dashboard is that the contour of the projected image does not match the black printed surface of the vehicle window, which is often curved in horizontal and vertical directions. Therefore, depending on the design of the system, image cropping and/or image distortion is required at the top or bottom of the displayed image.

Another disadvantage arises from the transition of several display elements. When rectangular display elements are combined and placed side by side to enlarge the virtual image displayed in the black print area from column to column, gaps are inevitably created between these display elements, even though these gaps can be reduced.

W02012080806A2 discloses a light source device for a vehicle.

EP2095988A1 describes a high visibility head-up display system.

WO2021209201 A1 discloses a projection arrangement for a head-up display with p-polarized radiation.

The present invention is based on the object of providing a head-up display with at least one image display device which eliminates the known disadvantages of an inconsistent image. According to the proposal of the invention, these and other tasks are solved by a vehicle window and a head-up display with such a vehicle window, as well as an appropriately equipped vehicle, according to the independent patent claims. Advantageous embodiments of the invention result from the subclaims.

According to the invention, the object is achieved in particular by a head-up display for a vehicle window, which in the installed state has an outside facing an external environment and an inside facing a vehicle interior and further comprises:

- at least one transparent pane,

- at least one masking strip in an edge area of the pane,

- at least one reflection layer, in particular applied using the printing process, for reflecting light, which is arranged in the area of the masking strip, on the vehicle interior side of the masking strip,

- At least one image display device assigned to the reflection layer with an image display directed at the reflection layer, the projected image of which is reflected by the reflection layer into the vehicle interior, the image display device being curved in the horizontal direction in plan view.

The head-up display according to the invention has, among other things, the following advantages. It offers greater possibilities for a large, seamless user interface displayed on the pillar-to-pillar black print display. There is therefore a greater possibility for the virtual image, especially for the distance and the viewing angle. The view of the user interface depends on the driver or passenger seat. There are no or at least less disruptive visual gaps between display elements. Less hardware is required. The number of display control boards can be reduced. The energy consumption of displays is lower because the display area can be used more effectively.

In the head-up display according to the invention, the curvature of the image display device is adapted to the vehicle window geometry, i.e. the display curvature should correspond as closely as possible to the horizontal curvature of the vehicle window in the black print area.

A preferred embodiment of the invention is a head-up display, in which an image is reflected from the reflection layer into the vehicle interior by a horizontally curved image display device. This results in a better viewing angle and better ergonomics. A straight and even top edge of the virtual image is achieved while the bottom edge of the virtual image is straightened by image distortion. The curvature of the display device is adapted to the vehicle window geometry. The display curvature should correspond as closely as possible to the horizontal curvature of the windshield in the black print area. Therefore, the image display device is preferably bent in such a way that the display edge further away from the vehicle window has the same radius of curvature at the edge of the projected image. Changing the curvature of the display creates additional possibilities for the virtual image, e.g. B. virtual image distance or viewing angle.

A preferred embodiment of the invention is a head-up display, wherein the horizontally curved image display device contains 1 to 10, preferably 1 to 5, particularly preferably 1 to 3 image display devices. This range for the number of image display devices has proven to be particularly advantageous. However, the gaps between the projected images of the image display devices can be used, for example, to separate the driver and passenger sides as well as a common center display, which enables more flexibility in display selection and integration.

Instead of a curved image display device, the image display according to the invention contains several curved image display devices arranged next to one another. The gaps can be used, for example, to separate the driver and passenger sides as well as a common center display, allowing more flexibility in display selection and integration.

A preferred embodiment of the invention is a head-up display, with the image display devices having no peripheral edge area. The gaps that occur can be further reduced if an edge region that typically surrounds the image display devices and is not suitable for radiating light is designed with the smallest possible width. The image display devices particularly preferably have no peripheral edge area.

A preferred embodiment of the invention is a head-up display, wherein the image display device is curved in accordance with the horizontal curvature of the vehicle window in an area irradiated with the projected image. Due to the image display device being adapted to the curvature of the vehicle window, there is greater freedom of design with regard to the image generated. The projected image can be visually perceived from more directions and angles. Disturbing gaps between projected images that would occur with multiple smaller image display devices can be avoided. A preferred embodiment of the invention is a head-up display, wherein the amount of light that the image display device emits is at least 50 lumens, preferably at least 200 lumens, particularly preferably at least 600 lumens. The ranges for the amount of light are very advantageous.

The head-up display according to the invention comprises a vehicle window, which serves to separate a vehicle interior from an external environment of the vehicle. The vehicle window comprises at least one transparent pane. The vehicle window can basically be designed in any way, in particular as a thermally toughened single-pane safety glass or as a composite pane. The vehicle window preferably serves as a vehicle windshield.

The head-up display according to the invention comprises a vehicle window, in particular a vehicle windshield, which is designed as a composite window and comprises a first window with an outside and an inside and a second window with an inside and an outside, which are firmly connected to one another by at least one thermoplastic intermediate layer (adhesive layer). are. The first pane can also be referred to as the outer pane and the second pane as the inner pane. The surfaces or sides of the two individual panes are usually referred to as side I, side II, side III and side IV from the outside to the inside.

The head-up display according to the invention comprises a vehicle window which, when installed in the vehicle, has an outside facing the external environment and an inside facing the vehicle interior. In the case of a vehicle window designed as a composite window, the outside of the first window is the outside of the vehicle window and the inside of the second window is the inside of the vehicle window.

The head-up display according to the invention comprises a vehicle window which has at least one masking strip in an edge region, which typically adjoins the edge of the window. The at least one masking strip is a coating made up of one or more layers and serves to mask structures that are otherwise visible through the pane when installed. Particularly in the case of a windshield, the masking strip is used to mask an adhesive bead for gluing the windshield into a vehicle body, that is, it prevents the view of the usually irregularly displayed The adhesive bead extends to the outside, creating a harmonious overall impression of the windshield. On the other hand, the masking strip serves as UV protection for the adhesive material used. Continuous exposure to UV light damages the adhesive material and would loosen the connection between the window and the vehicle body over time.

The head-up display according to the invention comprises a vehicle window which has at least one masking strip which is frame-shaped and has a greater width, in particular in a section which overlaps the reflection layer, than in other sections.

The at least one masking strip comprises a colored, preferably black, colored material that can preferably be burned into the pane. Preferably, the at least one masking strip is opaque, in particular to serve as visual and UV protection, for example for an adhesive bead. In the case of panes with an electrically controllable functional layer, the masking strip can also be used, for example, to cover busbars and/or connection elements.

For the purposes of the present invention, “transparent” means that the total transmission of the vehicle window corresponds to the legal regulations for windshields and preferably has a transmittance for visible light of more than 70% and in particular of more than 75%, for example more than 95%. Accordingly, “opaque” means a light transmission of less than 30%, in particular less than 25%, for example less than 5%, in particular 0%.

The head-up display according to the invention comprises a vehicle window, which further comprises at least one reflection layer (mirror layer) for reflecting light into the vehicle interior. What is important here is that the reflection layer is arranged in the area of the masking strip, on the vehicle interior side of the masking strip. When viewed from the inside of the vehicle window, the reflective layer is therefore in front of the masking strip.

The expression “in the area of the masking strip” means that the reflection layer is arranged in a vertical view through the vehicle window or in an orthogonal projection through the window in overlap with the masking strip. The reflection layer and the at least one masking strip can be arranged on different sides of the vehicle window or on the same side of the vehicle window. The reflective layer does not have a section that does not overlap the masking strip, ie the reflection layer is only formed where it is located in front of the masking strip in view of the inside of the vehicle window.

The expression “reflection of light into the vehicle interior” refers to the condition of the vehicle window installed in the vehicle. The reflected light leaves the vehicle window on the inside.

In the state of the vehicle window installed in the vehicle, at least one image display device arranged in the vehicle interior is assigned to at least one reflection layer. The image display device includes an image display whose image hits the reflection layer and is reflected into the vehicle interior by the reflection layer. The image display device can also be referred to as a display and can be designed as a TFT display, LED display, OLED display, EL display, pLED display or the like, preferably as a TFT display. Preferably, at least one image display device is assigned to the reflection layer. Particularly preferably, exactly one image display device is assigned to the reflection layer. With the usual dimensions of image displays, when using multiple image display devices, the projected images can extend over essentially the entire width of the vehicle window. This results in an improved user experience for passengers and the driver. With only one image display device, there are no gaps between the virtual images, which improves the user experience.

The image display device should preferably have a screen diagonal of 15 cm to 30 cm, particularly preferably 20 cm to 25 cm. Larger image displays have the advantage of requiring fewer image displays to be used, resulting in fewer visible gaps between the projected virtual images. Alternatively, the image display device preferably has a screen diagonal of 5 cm to 15 cm, particularly preferably 7 cm to 12 cm. Smaller image display devices require less image pre-distortion than larger image display devices. Smaller image display devices therefore deviate less from the horizontal radius of curvature of the vehicle window.

The thickness of the image display device is preferably from 0.1 cm to 5 cm, particularly preferably from 0.3 cm to 1 cm. With these dimensions, the image display device is well placed in the dashboard of a vehicle without being easily visible to a driver or passenger.

The amount of light that the image display device emits is at least 50 lumens, preferably at least 200 lumens, particularly preferably at least 600 lumens. The luminance of the light of the image display device reflected by the reflection layer is at least 500 cd/m ² , preferably at least 800 cd/m ² , particularly preferably 1000 cd/m ² . At this luminance, the projected image is easily visible to a viewer.

The reflection layer is designed to reflect light from the image display device. The reflection layer is a coating of the pane that reflects the incident light and preferably comprises or consists of at least one elemental metal and/or at least one metal oxide. The metal is preferably selected from the group consisting of aluminum, tin, titanium, copper, nickel, chromium, cobalt, iron, manganese, zirconium, cerium, yttrium, silver, gold, platinum and palladium, or mixtures thereof. The reflection layer is particularly preferably based on aluminum or a nickel-chromium alloy. Aluminum and nickel-chromium alloys have improved ability to reflect visible light. If something is “based on” a material, it consists predominantly of this material, in particular essentially of this material in addition to any impurities or dopants.

Alternatively, the reflection layer can also be a metal-containing or metal-free reflective film or a metal-coated film. The reflective film can be applied by means of an adhesive layer on different sides of the vehicle window or on the masking layer. However, the reflective film is particularly preferably arranged within the thermoplastic intermediate layer. “Within the thermoplastic intermediate layer” can mean that the reflective layer is arranged between two thermoplastic films before lamination or is pressed into a thermoplastic film using pressure.

To produce the reflection layer, a paste is applied to the pane or a film, for example by a vapor deposition process such as an atmospheric pressure plasma coating process, spray coating, or by a sol/gel process and, if necessary, subsequent baking or Tempering. The paste is preferably applied to the pane or film using a printing process, in particular by means of screen printing, pad printing or offset printing. The applied paste is then baked, ie compacted by heat treatment. The applied paste is advantageously dried at a temperature of 50 ° C to 180 ° C and calcined at a temperature of 200 ° C to 1000 ° C, in particular from 400 ° C to 700 ° C. The film is preferably a polymeric film containing polyethylene terephthalate (PET), polypropylene (PP) and/or polyethylene (PE) or the film contains in particular PET, PP and/or PE.

The paste comprises a printable metal solution, with at least one metal predominantly bound to a complex. The paste may further contain a solvent, preferably selected from alcohols, glycols, polypropylene glycols and derivatives thereof, and/or a thickener, preferably a cellulose derivative or polyacrylic acid.

To produce the reflection layer, a coating is alternatively applied to the pane or film, preferably by physical vapor deposition (PVD), particularly preferably by cathode sputtering (“sputtering”) and very particularly preferably by magnetic field-assisted cathode sputtering (“magnetron sputtering”). Such coatings can be produced with particularly high optical quality and particularly low thickness.

In principle, the coating can be applied, for example, by means of chemical vapor deposition (CVD), plasma-assisted vapor deposition (PECVD), vapor deposition or atomic layer deposition (ALD). The coating is preferably applied to the panes before lamination.

For example, the reflection layer consists of at least one metal oxide, optionally at least one solvent and/or at least one thickener, and unavoidable impurities, the proportion of which in the reflection layer is less than 5% by weight, preferably less than 1% by weight. The metal oxide content in the reflection layer is preferably at least 70%, preferably at least 80%, in particular at least 90%.

The reflection layer can advantageously improve the properties of the reflected light compared to mere reflection of the light on the pane.

In an advantageous embodiment of the invention, the reflection layer has a total reflectivity of light (R ) in the visible wavelength range, measured at an angle of incidence of 65° to the normal, of greater than 15%, preferably greater than or equal to 25%. The light here preferably includes s-polarized and p-polarized light in the visible wavelength range. The proportion of reflected light is therefore comparatively high, with the reflectivity of light (RL) being, for example, approximately 25%.

In addition, relatively high proportions of light that are polarized in the plane of incidence (p-polarization) can also advantageously be reflected.

In a further advantageous embodiment of the invention, the reflection layer has a reflectivity of p-polarized light ( _RP .L) in the visible wavelength range, measured at an angle of incidence of 65 ° to the normal, of greater than 5%, preferably greater than 15%.

The visible wavelength range in the context of the present invention is preferably 380 nm to 780 nm.

The above-mentioned reflection values apply particularly preferably to s- and p-polarized light or to p-polarized light in the wavelength range used by the light source. The indication of the direction of polarization refers to the plane of incidence of the radiation on the composite pane. P-polarized radiation refers to radiation whose electric field oscillates in the plane of incidence. S-polarized radiation refers to radiation whose electric field oscillates perpendicular to the plane of incidence. The plane of incidence is spanned by the incidence vector and the surface normal of the composite pane in the geometric center of the irradiated area.

The present invention is based on the knowledge that a reflection layer covering the at least one, typically opaque, masking strip enables good image representation with high contrast to the masking strip, so that it appears bright and is therefore also easy to see. This advantageously enables a reduction in the performance of the image display device and thus reduced energy consumption. This is a great advantage of the invention. The contrast ratio of the virtual image projected on the reflection layer is at least 2:1, preferably at least 3:1 and particularly preferably at least 5:1. The contrast ratio is the ratio between the light intensity of the brightest and darkest points of an image. Options for measuring the contrast ratio are generally known to those skilled in the art.

The masking strip is preferably applied to at least one pane using a printing process, in particular a screen printing process. The printing ink is printed on the disc and then preferably dried or baked at up to 700 °C. The printing ink is preferably permanently lightfast, solvent and abrasion resistant. The masking strip can transition from a solid coating into points of different sizes. These so-called screen printing dots are intended to break up the visually massive impression of the black screen printed edge.

The at least one masking strip is preferably black and can also be referred to as black printing or masking printing. The material of the masking strip can also be applied to the pane using other common application methods such as brushing, rolling, spraying and the like and then preferably baked.

According to a preferred embodiment of the vehicle window, the at least one masking strip consists of a single layer. This has the advantage of a particularly simple and cost-effective production of the vehicle window, since only a single layer has to be formed for the masking strip.

The masking strip can in principle be applied to each side of the pane. In the case of a composite pane, this is preferably applied to the inside (side II) of the first pane or to the inside (side III) of the second pane, where it is protected from external influences. It is particularly preferably applied to the inside (side II) of the first pane.

According to a preferred embodiment of the vehicle window according to the invention, which is designed in the form of a composite pane, the reflection layer is attached to the outside (side IV) of the second pane, which enables particularly simple production. As the inventors were able to show, the proportion of reflected light is particularly high with this arrangement. In addition, disturbing secondary images can be avoided. Although the reflection layer is generally very weather-stable, the reflection layer can be covered by a cover layer, in particular a polymer layer or a glass layer, in order to protect it from external influences. The glass layer can in particular be attached to the composite pane by a thermoplastic intermediate layer.

According to a further preferred embodiment of the vehicle window according to the invention, which is designed in the form of a composite pane, the reflection layer is attached to the inside (side III) of the second pane, which has the advantage that the reflection layer is protected from external influences. According to a further preferred embodiment of the vehicle window according to the invention, which is designed in the form of a composite pane, the reflection layer is attached to the inside (side II) of the first pane on or above the (opaque) masking layer. As the invention was able to surprisingly show, with this arrangement the proportion of reflected light with p-polarization is particularly high, which has the advantage that the HUD display is clearly visible even with sunglasses with polarized lenses. One or more further layers can be arranged between the masking layer and the reflection layer. Alternatively, the reflection layer can be applied directly to the masking layer.

According to a further preferred embodiment of the vehicle window according to the invention, in addition to the (opaque) masking strip on the inside (side II) of the first window, there is at least one further masking strip on the inside (III) of the second window and/or on the outside (IV). arranged on the second disk. The further masking strip serves to improve the adhesion of the windows and is preferably mixed with ceramic parts, which give the masking strip a rough and adhesive surface, which on side IV, for example, supports the gluing of the vehicle window into the vehicle body. On side III, this supports the laminating of the two individual panes of the composite pane. The masking strip arranged on side II is preferably also mixed with ceramic particles. A further masking strip applied to the outside of the second pane (side IV) can also be provided for aesthetic reasons, for example to conceal the edge of the reflection layer or to design the edge of the transition to the transparent area.

In a section in which the reflection layer is arranged in overlap with the opaque masking strip on side II, the masking strip is preferably provided with a widening, i.e. has a greater width (dimension perpendicular to the extension) than in other sections. In this way, the masking strip can be suitably adapted to the dimensions of the reflection layer.

The vehicle window preferably has an upper edge (also called roof edge), which faces the roof of the vehicle in the installed position, and a lower edge (also called engine edge), which faces the floor of the vehicle. The upper edge and the lower edge are connected to one another via two side edges that run essentially perpendicular to the upper and lower edges. In a preferred embodiment of the invention, the reflection layer extends over the entire width of the vehicle window. The reflective layer extends completely from one side edge to the other side edge. The reflection layer is arranged in a lower edge section directly adjacent to the lower edge. The width of the reflection layer is preferably 2 cm to 20 cm, particularly preferably 3 cm to 15 cm. In this embodiment, the vehicle window is preferably the windshield of a car. The reflection layer is arranged outside the area of the windshield intended for viewing. In the European Union market, this means that the reflective layer is arranged below the field of view A and B of the windshield according to ECE R43. Important information can be projected into a driver's field of vision, such as the current driving speed, navigation or warning information, which the driver can perceive without having to look far away from the road. As part of a head-up display, the reflective layer can also replace functions of a space-consuming generic display in the dashboard, thereby freeing up space in the vehicle.

The at least one pane preferably contains or consists of glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass, alumino-silicate glass, or clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate , polystyrene, polyamide, polyester, polyvinyl chloride and/or mixtures thereof. Suitable glasses are known, for example, from EP 0 847 965 B1.

The at least one pane can be clear, or tinted or colored. Windshields must have sufficient light transmission in the central viewing area, preferably at least 70% in the main viewing area A according to ECE-R43. The at least one disk is preferably curved, that is to say it has a curvature.

The at least one pane can have other suitable, known coatings, for example anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings or sun protection coatings or low-E coatings.

The thickness of one pane can vary widely and be adapted to the requirements of the individual case. Discs with standard thicknesses of 1.0 mm to 25 mm and preferably 1.4 mm to 2.1 mm are preferably used. The size of the discs can vary widely and depends on the use. The vehicle window can have any three-dimensional shape. Preferably, the at least one pane has no shadow zones, so that it can be coated, for example, by cathode sputtering. Preferably, the at least one disk is planar or slightly or strongly curved in one direction or in several directions of the room. The at least one disc can be colorless or colored.

The at least one thermoplastic intermediate layer contains or consists of at least one thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or polyurethane (PU) or copolymers or derivatives thereof, optionally in combination with polyethylene terephthalate (PET). The thermoplastic intermediate layer can also, for example, polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyacetate resin, casting resin, acrylate, fluorinated ethylene-propylene, polyvinyl fluoride and / or ethylene-tetrafluoroethylene, or contain a copolymer or mixture thereof.

The thermoplastic intermediate layer preferably contains or consists of polyvinyl butyral (PVB), particularly preferably polyvinyl butyral (PVB) and additives known to those skilled in the art, such as plasticizers. The thermoplastic intermediate layer preferably contains at least one plasticizer.

Plasticizers are chemical compounds that make plastics softer, more flexible, supple and/or elastic. They shift the thermoelastic range of plastics towards lower temperatures, so that the plastics have the desired more elastic properties in the operating temperature range. Preferred plasticizers are carboxylic acid esters, especially low-volatility carboxylic acid esters, fats, oils, soft resins and camphor. Other plasticizers are preferably aliphatic diesters of tri- or tetraethylene glycol. Particularly preferred plasticizers used are 3G7, 3G8 or 4G7, where the first number denotes the number of ethylene glycol units and the last digit denotes the number of carbon atoms in the carboxylic acid part of the compound. So 3G8 stands for triethylene glycol bis-(2-ethylhexanoate), ie for a compound of the formula C4H9CH (CH2CH3) CO (OCH ₂ CH ₂ )3O ₂ CCH (CH ₂ CH ₃ ) C4H9. The thermoplastic intermediate layer preferably contains at least 3% by weight, preferably at least 5% by weight, particularly preferably at least 20% by weight, even more preferably at least 30% by weight and in particular at least 40% by weight of a plasticizer. The plasticizer preferably contains or consists of triethylene glycol bis-(2-ethylhexanoate).

More preferably, the thermoplastic intermediate layer contains at least 60% by weight, particularly preferably at least 70% by weight, in particular at least 90% by weight and, for example, at least 97% by weight, of polyvinyl butyral.

The thermoplastic intermediate layer can be formed by a single film or by more than one film.

The thermoplastic intermediate layer can be formed by one or more thermoplastic films arranged one above the other, the thickness of the thermoplastic intermediate layer preferably being from 0.25 mm to 1 mm, typically 0.38 mm or 0.76 mm. However, it would also be conceivable that the thickness of transparent adhesives is approx. 10 pm.

The thermoplastic intermediate layer can also be a functional thermoplastic intermediate layer, in particular an intermediate layer with acoustically dampening properties, an intermediate layer that reflects infrared radiation, an intermediate layer that absorbs infrared radiation and/or an intermediate layer that absorbs UV radiation. For example, the thermoplastic intermediate layer can also be a band filter film that blocks out narrow bands of visible light.

The head-up display comprises an image display device assigned to the reflection layer with an image display directed onto the reflection layer, the image of which is reflected by the reflection layer into the vehicle interior. If multiple reflective layers are provided, a corresponding number of image display devices may be provided.

The invention further extends to a vehicle with a head-up display according to the invention. The image display device is preferably supplied with power via the vehicle's on-board electrical system. The electricity from the on-board electrical system can be generated, for example, via solar cells on the vehicle roof. The invention further relates to a method for producing a head-up display according to the invention. The procedure includes:

(a) at least one masking strip is applied in the edge area of at least one pane,

(b) the reflection layer is arranged in the area of the masking strip on the vehicle interior side and

(c) the image display device is arranged in relation to the vehicle window and its geometry.

The masking strip is preferably applied to the at least one pane using a printing process, in particular a screen printing process, or via other common application processes such as brushing, rolling, spraying and the like, and then preferably baked. The reflective layer is preferably applied to the pane using a printing process and baked.

To produce a composite pane, at least two panes are preferably connected (laminated) to one another by at least one thermoplastic adhesive layer under the influence of heat, vacuum and/or pressure. Methods known per se can be used to produce a composite pane. For example, so-called autoclave processes can be carried out at an increased pressure of about 10 bar to 15 bar and temperatures of 130 ° C to 145 ° C for about 2 hours. Known vacuum bag or vacuum ring processes work, for example, at around 200 mbar and 130 ° C to 145 ° C. The two disks and the thermoplastic intermediate layer can also be pressed into a composite disk in a calender between at least one pair of rollers. Systems of this type are known for producing composite panes and usually have at least one heating tunnel in front of a press shop. The temperature during the pressing process is, for example, from 40 °C to 150 °C. Combinations of calender and autoclave processes have proven particularly useful in practice. Alternatively, vacuum laminators can be used. These consist of one or more heatable and evacuable chambers in which the first pane and second pane can be laminated within, for example, about 60 minutes at reduced pressure of 0.01 mbar to 800 mbar and temperatures of 80 ° C to 170 ° C.

Furthermore, the invention extends to the use of the head-up display according to the invention with a vehicle window in vehicles for traffic on land, in the air or on Water, especially in motor vehicles. According to the invention, the use of the vehicle window as a vehicle windshield is preferred.

The composite pane can advantageously be the windshield or roof pane of a vehicle or other vehicle glazing, for example a separating pane in a vehicle, preferably in a rail vehicle or a bus. In principle, a composite pane with the characteristics of the vehicle pane can also be architectural glazing, for example in an outer facade of a building or a separating pane inside a building.

The various embodiments of the invention can be implemented individually or in any combination. In particular, the features mentioned above and to be explained below can be used not only in the specified combinations, but also in other combinations or on their own, without departing from the scope of the present invention.

The invention is explained in more detail below using exemplary embodiments, with reference being made to the attached figures. It shows in a simplified, not true-to-scale representation:

1 shows a cross-sectional view of an exemplary embodiment of the head-up display according to the invention,

2 shows a top view of the vehicle window from FIG. 1,

3-4 cross-sectional views of various designs of the vehicle window,

5 shows a further exemplary embodiment of the head-up display according to the invention with a view of the vehicle window with a curved image display device and

6 shows a further exemplary embodiment of the head-up display according to the invention with a view of the vehicle window with three curved image display devices and

Figure 1 shows a cross-sectional view of an exemplary embodiment of the head-up display 100 according to the invention in a vehicle in a highly simplified, schematic representation. A top view of the vehicle window 1 of the head-up display 100 is shown in Figure 2. The cross-sectional view of Figure 1 corresponds to the section line AA of the vehicle window 1, as indicated in Figure 2.

The vehicle window 1 is designed in the form of a composite window (see also Figures 3 to 4) and comprises a first window 2 (e.g. outer window) and a second window 3 (e.g. inner window), which are firmly connected to one another by a thermoplastic intermediate layer 4. The vehicle window 1 is installed in a vehicle and separates a vehicle interior 12 from an external environment 13. For example, the vehicle window 1 is the windshield of a motor vehicle. Alternatively, the vehicle window only has a single pane, preferably in the form of thermally toughened toughened safety glass (not shown). The first pane 2 and the second pane 3 each consist of glass, preferably thermally toughened soda-lime glass, and are transparent to visible light. The thermoplastic intermediate layer 4 consists of a thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and/or polyethylene terephthalate (PET).

The outer surface I of the first pane 2 faces the external environment 13 and is at the same time the outer surface of the vehicle window 1. The inner surface II of the first pane 2 and the outer surface III of the second pane 3 each face the intermediate layer 4. The inner surface IV of the second pane 3 faces the vehicle interior 12 and is at the same time the inner surface of the vehicle pane 1. It is understood that the vehicle pane 1 can have any suitable geometric shape and/or curvature. As a vehicle window 1, it typically has a convex curvature.

In the edge region 11 of the vehicle window 1 there is a frame-shaped first masking strip 5 on the inside (side II) of the first window 2. The first masking strip 5 is opaque and prevents the view of structures arranged on the inside of the vehicle window 1, for example an adhesive bead for gluing in Vehicle window 1 into a vehicle body. The first masking strip 5 is preferably black. The first masking strip 5 consists of an electrically non-conductive material conventionally used for masking strips, for example a black-colored screen printing ink that is baked.

Furthermore, the vehicle window 1 has a second masking strip 6 made of an electrically non-conductive material in the edge region 11 on the outside IV of the second window 3. The second masking strip 6 is designed in a frame-shaped circumferential manner. Like the first masking strip 5, the second masking strip 6 consists of an electrically non-conductive material conventionally used for masking strips, for example a black-colored screen printing ink that is baked.

On the outside IV of the second disk 3 there is a reflection layer 9, which is applied to the disk 3 and baked, for example by means of magnetron sputtering or as a paste in the printing process. The reflection layer is a metal oxide coating containing at least one metal oxide or, for example, a nickel-chromium alloy. The reflection layer 9 is arranged in a vertical view through the vehicle window 1 in overlap with the first masking strip 5, with the first masking strip 5 completely covering the reflection layer 9, ie the reflection layer 9 has no section that is not in overlap with the first masking strip 5. Here, for example, the reflection layer 9 is only arranged in the lower (engine-side) section 11 'of the edge region 11 of the vehicle window 1. However, it would also be possible to arrange the reflection layer 9 in the upper (roof-side) section 11" or in a side section of the edge area 11. Furthermore, several reflection layers 9 could be provided, which are arranged, for example, in the lower (engine-side) section 11′ and in the upper (roof-side) section 11″ of the edge region 11. For example, the reflection layers 9 could be arranged in such a way that a (partially) rotating image is generated.

The first masking strip 5 is widened in the lower (engine-side) section 11' of the edge region 11, i.e. the first masking strip 5 has a greater width in the lower (engine-side) section 11' of the edge region 11 than in the upper (roof-side) section 11'' of the edge region 11 (as well as in the side sections of the edge region 11 that cannot be seen in FIG. 1) of the vehicle window 1. The “width” is understood to be the dimension of the first masking strip 5 perpendicular to its extension. The reflection layer 9 is here, for example, arranged above the second masking strip 6 (i.e. not in overlap), although it would equally be possible for there to be an overlap for aesthetic reasons.

The head-up display 100 also has an image display device 8 arranged in the dashboard 7 as an image generator. The image display device 8 is used to generate light 10 (image information), which is directed onto the reflection layer 9 and is reflected by the reflection layer 9 as reflected light 10 'into the vehicle interior 12, where it can be seen by an observer, for example a driver. The reflection layer 9 is designed to reflect the light of the image display device, ie an image of the image display. It would also be possible, for example, to arrange the image display device 8 in the A-pillar of a motor vehicle or on the roof (in each case on the vehicle interior side), if the reflection layer 9 is positioned in a suitable manner for this purpose. If several reflection layers 9 are provided, each reflection layer 9 can be assigned a separate image display device 8, ie several image display devices 8 can be arranged. If more than one virtual image is to be displayed on the reflection layer 9, these can also be generated by more than one image display device 8. It would also be possible, for example, for the vehicle window 1 to be a roof window, side window or rear window. The vertical distance of the image display device 8 to the area of the reflection layer 9, which is provided for reflecting the light 10 of the image display device 8, is preferably 0.1 to 10 cm, for example 2 cm. The image display device 8 is, for example, a TFT display and the amount of light emitted is, for example, 600 lumens. The image display device 8 is, for example, electrically connected to the vehicle's on-board electrical system and is supplied with power therefrom (not shown). The inventive design of the one or more image display devices 8 is described in Figures 5 or 6.

In the top view of Figure 2, the reflection layer 9 is shown extending along the lower section 11 ' of the edge region 11.

Reference is now made to Figures 3 to 4, in which cross-sectional views of various embodiments of the vehicle window 1 are shown. The cross-sectional views of Figures 3 to 4 correspond to the section line AA in the lower section 1T of the edge region 11 of the vehicle window 1, as indicated in Figure 2.

In the variant of the vehicle window 1 shown in Figure 3, the first (opaque) masking strip 5 is located on the inside (side II) of the first pane 2. The reflection layer 9 is applied to the outside (side IV) of the second pane 3. Light 10 from the image display device 8 is reflected into the vehicle interior 12 by the reflection layer 9 as reflected light 10 '. The polarizations of the light 10, 10' (s-polarization, p-polarization) are illustrated schematically. This variant has the advantage that a relatively large proportion of the incident light 10 is reflected. In addition, the image is clearly visible against the background of the opaque (first) masking layer 5 with high contrast.

The variant of the vehicle window 1 shown in Figure 4 differs from the variant of Figure 3 only in that the reflection layer 9 is applied to the (first) masking layer 5. This variant has the particular advantage that a relatively large proportion of the incident light 10 is reflected with p-polarization. In addition, the image is clearly visible against the background of the opaque (first) masking layer 5 with high contrast. The reflection layer 9 is well protected from external influences inside the composite pane. In all exemplary embodiments, the reflection layer 9 is arranged on the vehicle interior side of the first masking strip 5, that is, when viewed from the inside of the vehicle window 1, the reflection layer 9 is located in front of the first masking strip 5.

Figure 5 shows a top view of the vehicle window 1 and a side view of the image display device 8 of the head-up display 100. The top view shows the interior side of the vehicle window 1, which faces the vehicle interior (outside IV). The vehicle window 1 is designed, for example, as described for Figure 1 and Figure 2. The vehicle window 1 has, for example, the geometric shape and curvature usual for windshields. The vehicle window 1 is installed in a vehicle as a windshield, for example.

The image display device 8 projects an image 14 onto the reflection layer 9 of the vehicle window 1 by means of emitted light 10. The image display device 8 is curved in the horizontal direction in a top view of the display area of the image display device 8. In the side view of the image display device 8 shown, it is therefore vertically curved. The image display device 8 is curved convexly in front of the vehicle window 1 in a side view; but it can also be concavely curved. The curvature of the image display device 8 is adapted to the horizontal curvature of the vehicle window 1 in the area of the reflection layer 9 intended for the projected image 14. The image display device 8 is preferably curved in such a way that the display edge of the image display device 8 which is further away from the vehicle window root has the same radius of curvature as the vehicle window 1 at the upper edge O of the projected image 14. In this way, a straight and uniform upper edge O of the virtual Image 14 can be achieved, while the lower edge U of the projected image 14 can be straightened by correcting the image distortion. Particularly preferably, there is a fixed correlation of the radius of curvature of the vehicle window 1 in the area of the projection of the projected image 14 to the radius of curvature of the image display device 8. The curvature of the image display device 8 is preferably selected so that the projected image 14 is clearly visible to a driver or passenger over a vehicle Majority (>90%) of the width of the vehicle window 1 extends.

Due to the image display device 8 adapted to the curvature of the vehicle window 1, there is greater design freedom with regard to the image 14 generated. The projected image 14 can be visually perceived from more viewing directions and angles. Disturbing gaps between projected images 14, which would occur with several smaller image display devices 8, can be avoided. By having fewer image display devices 8, energy costs and material costs can be saved. Due to the curvature of the image display device 8, less image correction is necessary. Image corrections mean that the projected image 14 can only be imaged on a smaller area of the reflection layer 9 than would actually be possible due to the design of the image display device 8.

The variant of the head-up display 100 shown in FIG. 6 only differs from the variant of FIG on the vehicle window 1. The head-up display 100 instead of a curved image display device 8 _n contains horizontally curved image display devices, each of which projects an image 14 _n onto the reflection layer 9 of the vehicle window 1. The first image display device 81 projects a first image 14i, the second image display device 82 projects a second image 142 and the third image display device 83 projects a third image 14s onto the reflection layer 9 of the vehicle window 1. The three image display devices 81, 82, 83 are arranged next to one another, wherein the second projected image 142 is located between the first and second images 14i, 14s and centrally near the disk root. Viewed together, the three image display devices 81, 82, 83 result in a similar geometry to the one image display device 8 shown in FIG. 5, i.e. a convex curvature. This means that the individual image display devices 81, 82, 83 are also adapted to the curvature of the vehicle window 1.

Gaps occur between the projected images 14i, 142, 14s. However, these gaps can also be used, for example, to separate the driver and passenger sides as well as a shared central image display device 82, which enables more flexibility in the selection and integration of the image display devices 81, 82, 83. Easier independent operation of the individual image display devices is also possible 81, 82, 83. Due to the curvature of the individual image display devices 81, 82, 83, the gaps that occur between the projected images 14i, 142, 14s can also be compared to projected images from generic image display devices be reduced. The gaps that occur can be reduced even further if an edge region that typically surrounds the image display devices 81, 82, 83 and is not suitable for radiating light 10 is designed with the smallest possible width. The image display devices 81, 82, 83 particularly preferably have no peripheral edge area. From the above statements it follows that the invention provides an improved vehicle window or a head-up display equipped with it, which enables good image representation with high contrast to the masking strip. Unwanted secondary images can be avoided. The head-up display according to the invention can be produced easily and inexpensively using known manufacturing processes.

Show it:

1 vehicle window

2 first slice

3 second slice

4 intermediate layer

5 first masking strips

6 second masking strip

7 dashboard

8 image display device

81 first image display device

82 second image display device

83 third image display device

9 reflective layer

10, 10' light

11, 11', 11" edge area

12 vehicle interior

13 external environment

14 projected image

141 first projected image

142 second projected image

14s third projected image

100 head-up display

I, II Outside of the first pane 2, inside of the first pane 2

III; IV Inside of the second disk 3, outside of the second disk 3 n an integer from 1 to 10

O Top edge of the projected image 14

U Bottom of the projected image 14

A-A’ cutting line

Claims

Patent claims

1. Head-up display (100) for a vehicle window (1) with an outside (I) facing an external environment (13) in the installed state and an inside (IV) facing a vehicle interior, comprising:

- at least one transparent pane (2, 3),

- at least one masking strip (5) in an edge region (11) of the pane (2, 3),

- at least one reflection layer (9), in particular applied using the printing process, for reflecting light, which is arranged in the area of the masking strip (5), on the vehicle interior side of the masking strip,

- at least one image display device (8) assigned to the reflection layer (9) with an image display directed onto the reflection layer (9), the projected image (14) of which is reflected by the reflection layer (9) into the vehicle interior (12), the image display device (8 ) is curved in the horizontal direction in plan view.

2. Head-up display (100) according to claim 1, wherein the horizontally curved image display device (8) contains 1 to 10 image display devices (8 _n ) and n is an integer from 1 to 10.

3. Head-up display (100) according to claim 1 or 2, wherein the horizontally curved image display device (8) contains 1 to 5 image display devices (8 _n ).

4. Head-up display (100) according to claim one of claims 1 to 3, wherein the horizontally curved image display device (8) contains 1 to 3 image display devices (8 _n ).

5. Head-up display (100) according to one of claims 1 to 4, wherein an image (14 _n ) is reflected from the reflection layer (9) into the vehicle interior (12) by an image display device (8 _n ).

6. Head-up display (100) according to one of claims 1 to 5, wherein the image display devices (8) have no peripheral edge area which is not suitable for radiating light.

7. Head-up display (100) according to one of claims 1 to 6, wherein the image display device (8) is curved in accordance with the horizontal curvature of the vehicle window (1) in an area irradiated with the projected image (14).

8. Head-up display (100) according to one of claims 1 to 7, wherein the amount of light which the image display device (8) emits is at least 50 lumens, preferably at least 200 lumens, particularly preferably at least 600 lumens.

9. Head-up display (100) according to one of claims 1 to 8, wherein the image display device (8) is an LED display, OLED display or pLED display.

10. Head-up display (100) according to one of claims 1 to 9, wherein the vehicle window (1) is designed in the form of a composite window and a first window (2) with an outside facing the external environment (13) in the installed state (I) and an inside (II) and a second pane (3) with an inside (III) facing the vehicle interior (12) in the installed state and an outside (IV), which are firmly connected to one another by at least one thermoplastic intermediate layer (4). are included.

11. Head-up display (100) according to one of claims 1 to 10, wherein the vehicle window (1) has at least one masking strip (5) which is designed in the shape of a frame and in particular in a section (11 ') which overlaps to the reflection layer (9), has a greater width than in sections (11") different therefrom.

12. Head-up display (100) according to one of claims 1 to 11, wherein the vehicle window (1) has a reflection layer (9) which contains at least one elemental metal or a metal oxide, selected from the group consisting of aluminum, Tin, titanium, copper, nickel, chromium, cobalt, iron, manganese, zirconium, cerium, yttrium, silver, gold, platinum and palladium, or mixtures thereof.

13. Head-up display (100) according to one of claims 1 to 12, wherein the reflection layer (9) has a reflectivity of p-polarized light in the visible wavelength range, measured at an angle of incidence of 65 ° to the normal, of greater than 5%, preferably greater than 15%.

14. Head-up display (100) according to one of claims 1 to 13, wherein the reflection layer (9) is applied as a paste in the printing process to the pane (2, 3) or a film and baked.

15. Head-up display (100) according to one of claims 1 to 14, wherein the projected image (14) is displayed from pillar to pillar.

16. Head-up display (100) according to one of claims 10 to 15, wherein the masking strip (5) is applied to the inside (II) of the first pane (2).

17. A method for producing the head-up display (100) according to one of claims 1 to 16, wherein

(a) at least one masking strip (5) is applied in the edge region (11) of at least one pane (2, 3),

(b) the reflection layer (9) is arranged in the area of the masking strip (5), on the vehicle interior side and

(c) the image display device (8) is arranged in relation to the vehicle window (1) and its geometry.

18. A method for producing the head-up display (100) according to claim 17, wherein the reflection layer (9) is applied as a paste in the printing process to the pane (2, 3) or a film and baked.

19. Use of the head-up display (100) according to one of claims 1 to 16 in vehicles for traffic on land, in the air or on water, in particular as a vehicle windshield.