Composite sheet material for projection components that can be locally heated

Abstract

The present invention relates to a composite sheet (1), particularly for a projection assembly (100), the composite sheet comprising at least: - an outer sheet (2), an inner sheet (3), and a thermoplastic interlayer (4) disposed between the outer sheet (2) and the inner sheet (3), wherein the outer sheet (2) and the inner sheet (3) have outer sides (I, III) and inner sides (II, IV), respectively, and the inner side (II) of the outer sheet (2) and the outer side (III) of the inner sheet (3) face each other, and - the thermoplastic interlayer (4) comprises at least A masking layer (5) or consisting of at least one masking layer, wherein the masking layer (5) is opaque in at least one region (5'), a heating element (6) arranged within the opaque region (5') of the masking layer (5), and a reflective layer (11) adapted to reflect visible light (12), wherein the reflective layer (11) is spatially arranged in front of the masking layer (5) and at least partially overlaps with the opaque region (5') of the masking layer (5) in the viewing direction from the inner sheet (3) to the outer sheet (2).

Description

Technical Field

[0001] This invention relates to a composite sheet for projection components that can be locally heated, a method for manufacturing the same, its uses, and projection components. Background Technology

[0002] Head-up displays (HUDs) are now commonly used in vehicles and aircraft. The principle behind an HUD is that it operates by using an imaging unit that projects an image using optical modules and a projection surface. This image is perceived as a virtual image by the driver. If this image is reflected onto, for example, a windshield panel of the vehicle serving as the projection surface, important information can be presented to the user, significantly improving traffic safety.

[0003] Vehicle windshields typically consist of two glass sheets laminated together by at least one thermoplastic film. In the case of commonly used head-up displays (HUDs), a problem arises where the projected image is reflected at both surfaces of the windshield. Therefore, the driver perceives not only the desired primary image, caused by reflections from the inner surface of the windshield (primary reflection), but also a slightly offset and generally less intense secondary image caused by reflections from the outer surface of the windshield (secondary reflection). This problem is typically solved by arranging the reflective surfaces at a selectively chosen angle so that the primary and secondary images overlap, thus reducing the distracting appearance of the secondary image.

[0004] The illumination from head-up display (HUD) projectors is typically predominantly S-polarized because windshield sheets have better reflective properties compared to P-polarized light. However, if the driver wears polarization-selective sunglasses that only transmit P-polarized light, the driver will perceive the HUD image almost entirely or not at all. Therefore, there is a need for HUD projection components that are compatible with polarization-selective sunglasses. Thus, the solution to this problem is to apply projection components that use P-polarized light.

[0005] Another issue is the perceptibility of information transmitted through reflected images regardless of weather conditions and lighting. Important and safety-related information must be fully perceptible to drivers at any time of day or night, and in strong sunlight or rain. Therefore, when designing displays based on head-up displays, projectors must therefore have correspondingly high power to ensure that the projected image is sufficiently bright, especially in sunlight, and easily recognizable by the observer. This requires a projector of a certain size and incurs corresponding current consumption.

[0006] DE102014220189A1 discloses a head-up display (HUD) projection assembly that operates with p-polarized radiation to produce a HUD image. Since the angle of incidence is typically close to the Brewster angle, and therefore the p-polarized radiation is reflected by the glass surface to a small extent, the windshield sheet has a reflective structure that can reflect the p-polarized radiation towards the driver. As the reflective structure, a single metal layer with a thickness of 5 nm to 9 nm, for example made of silver or aluminum, is proposed, which is applied to the outer side of the inner sheet facing away from the interior space of the car.

[0007] US2004 / 0135742A1 also discloses a head-up display projection assembly that operates with p-polarized radiation to generate a head-up display image and has a reflective structure that reflects p-polarized radiation toward the driver. As a reflective structure, a multilayer polymer layer disclosed in WO96 / 19347A3 is proposed.

[0008] When designing displays based on head-up display technology, it is also essential to ensure that the projector has sufficiently high power to provide adequate brightness for the projected image, especially under sunlight, and to ensure it is easily recognizable by the observer. This requires a certain size for the projector and results in corresponding current consumption and heat emission.

[0009] A display, essentially based on the same principle as a HUD, can also be generated in the masked area. Therefore, the masked area is also illuminated by a projector and reflected there, thereby creating a display for the driver. Information, such as clock time, vehicle speed, engine speed, or navigation system indications, currently displayed in the dashboard area, or an image from a rear-facing camera (replacing a classic exterior or rearview mirror), can then be presented directly onto the windshield sheet in a practical and aesthetically pleasing manner, for example, in the section of the masked area adjacent to the lower edge of the windshield sheet. This type of projection assembly is known, for example, from DE102009020824A1.

[0010] Another major challenge while driving is heating the windshield sheet to prevent it from icing or fogging, which can obstruct visibility. This is especially true in the area near the lower edge of the windshield sheet within the vehicle's interior, where moisture often condenses due to intrusion. Sheet heating is typically achieved by heating air, which is then blown onto the sheet through an inlet. This type of heating is classified under Heating, Ventilation, and Air Conditioning (HVAC) methods. In addition to the significant energy consumption, the inlet, which delivers hot air and blows it onto the sheet, requires considerable space. Furthermore, the exhaust nozzles must be geometrically positioned relative to the sheet, which significantly limits design and structural freedom.

[0011] Alternatively, the sheet itself can have an electrically heating function. For example, a composite glass sheet is known from DE10352464A1, in which an electrically heated wire is placed between two glass sheets. The specific heating power can be adjusted by the ohmic resistance of the wire. For design and safety reasons, the number and diameter of the wire must be kept as small as possible. The wire must not be visually imperceptible or nearly imperceptible in daylight or at night under headlight illumination. Summary of the Invention

[0012] Therefore, the objective of this invention is to provide an improved composite sheet for a projection assembly based on HUD technology.

[0013] According to the present invention, the objective of the invention is achieved by the composite sheet according to the invention. Preferred embodiments are known from the present invention.

[0014] According to the present invention, a composite sheet is described, which is particularly configured for projection assemblies. The composite sheet comprises at least: -Outer sheet, inner sheet, and thermoplastic interlayer disposed between the outer sheet and the inner sheet, - Heating element, and -Reflective layer.

[0015] The outer sheet and inner sheet each have an outer side and an inner side, with the inner side of the outer sheet and the outer side of the inner sheet facing each other. A reflective layer is designed to reflect visible light. The thermoplastic interlayer includes or is composed of at least one masking layer, which is opaque in at least one region. A heating element is arranged within the opaque region of the masking layer. The reflective layer is spatially arranged ahead of the masking layer in the viewing direction from the inner sheet to the outer sheet and at least partially overlaps with the opaque region of the masking layer.

[0016] "The reflective layer is suitable for reflecting visible light" means that the reflective layer can reflect visible light to a certain extent and is configured to reflect visible light from the image display device. Preferably, the reflective layer reflects at least 1% of the visible light hitting the reflective layer.

[0017] The reflective layer can be disposed on the inner or outer side of the inner sheet. The reflective layer may have sections that do not overlap with the opaque areas of the masking layer. In the context of this invention, "viewing direction from the inner sheet to the outer sheet" refers to the viewing direction in the orthogonal direction from the plane of the inner sheet to the outer sheet.

[0018] The composite sheet is configured to separate the interior space from the external environment. The inner side of the inner sheet faces the interior space, and the outer side of the outer sheet faces the external environment.

[0019] The opaque areas of the reflective layer and the masking layer partially or completely overlap. For this reason, good image rendering with high contrast results in the opaque areas of the masking layer appearing bright and thus easily identifiable. This advantageously reduces the power consumption of the image display device configured to project imaging light onto the reflective layer. Consequently, reduced energy consumption and heat generation occur. The arrangement of heating elements in the opaque areas of the masking layer allows for heating of the composite sheet, thereby reducing fogging (condensation on the inner or outer sheet) in the generally opaque areas and in the opaque areas overlapping with the reflective layer. Therefore, when the composite sheet is installed in a vehicle as a vehicle sheet, the space in the dashboard area can be significantly reduced. This leads to the possibility of thinner designs within the vehicle's interior space. The image rendering via the reflective layer before the opaque areas can replace displays typically mounted on the dashboard, such as speedometers, tachometers, warning indicators, and fuel tank displays. Heating the composite sheet via a heating element replaces the input conduit that typically guides air heated by engine heat to the windshield sheet. If current flows through the heating element, it is heated due to its resistance and by means of Joule heating. Furthermore, eliminating the air exhaust nozzle, which is usually positioned in a specific geometry relative to the glass assembly, provides additional geometric freedom in the design of the vehicle's interior space. Moreover, heating the composite sheet via electrical energy is more energy efficient than heating it via engine-heated air. The composite sheet according to the invention can be manufactured simply and cost-effectively using known manufacturing methods. The following describes different preferred layer sequences of the composite sheet according to the present invention: -Outer sheet-Mask layer-Reflective layer-Inner sheet -Outer sheet -Mask layer -Inner sheet -Reflective layer The composite sheet is configured to separate the interior space from the external environment. The inner side of the inner sheet faces the interior space, while the outer side of the outer sheet faces the external environment. In the context of this invention, "the reflective layer is spatially arranged ahead of the masking layer in the viewing direction from the inner sheet to the outer sheet" means that the reflective layer is spatially closer to the interior space than the masking layer. Therefore, when viewed through the composite sheet from the interior space, the reflective layer is spatially arranged ahead of the masking layer. The composite sheet preferably has two opposing side edges, an upper edge, and a lower edge. The upper edge is configured to be positioned in the upper region in the mounting position, while the opposing lower edge is configured to be positioned in the lower region in the mounting position. The entire surface of the composite sheet is obtained by calculating the area using the side edges, the upper edge, and the lower edge. The entire surface size of the composite sheet is the same as the outer and inner sides of the inner and outer sheets.

[0020] In the context of this invention, "transparent" means that the total transmittance of the composite sheet meets the legal requirements for windproof sheets (e.g., EU regulation ECE-R43) and preferably has a transmittance of more than 30%, and especially more than 60%, such as more than 70%, for visible light (according to ISO 9050:2003). Correspondingly, "opaque" means a light transmittance of less than 15%, preferably less than 10%, particularly preferably less than 5%, and especially 0%.

[0021] In another preferred embodiment of the invention, the masking layer further has transparent areas, and the opaque areas preferably extend over less than 30% of the entire surface of the composite sheet, particularly preferably over less than 20% of the entire surface of the composite sheet, and especially over less than 10% of the entire surface of the composite sheet. In this case, the masking layer is constructed as at least one thermoplastic composite film that partially has transparent areas and partially has opaque areas. If the composite sheet is used as an observation sheet, for example as a transportation sheet, the proportion of the transparent area is advantageously larger than the proportion of the opaque area.

[0022] Alternatively, the thermoplastic interlayer may include at least a masking layer and at least one transparent layer. Furthermore, the masking layer is preferably completely opaque. The masking layer preferably extends over less than 30% of the entire surface of the composite sheet, particularly preferably over less than 20% of the entire surface of the composite sheet, and especially over less than 10% of the entire surface of the composite sheet. The thermoplastic interlayer may also be constructed from multiple masking and transparent layers. Therefore, a variety of composite films with different properties can be used in the manufacture of the composite sheet. Furthermore, fully colored composite films are technically easier to manufacture than composite sheets with only partial coloring. The masking and transparent layers are constructed as thermoplastic composite films. In the manufacture of the composite sheet according to the invention, the thermoplastic composite films may slightly overlap due to manufacturing processes. Preferably, the transparent layer and the masking layer overlap by 1 cm or less.

[0023] The masking layer and / or transparent layer comprises or is composed of at least one thermoplastic, preferably polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and / or polyurethane (PU), or copolymers or derivatives thereof, and may be combined with polyethylene terephthalate (PET) if possible. However, the masking layer and / or transparent layer may also comprise, for example, polypropylene (PP), polyacrylate, polyethylene (PE), polycarbonate (PC), polymethyl methacrylate, polyvinyl chloride, polyacetic acid resin, casting resin, acrylate, fluorinated ethylene propylene, polyvinyl fluoride, and / or ethylene tetrafluoroethylene, or copolymers or mixtures thereof.

[0024] The masking layer and / or transparent layer are preferably configured as at least one thermoplastic composite film and contain or constitute polyvinyl butyral (PVB), particularly preferably composed of polyvinyl butyral (PVB) and additives known to those skilled in the art, such as plasticizers. The masking layer and / or transparent layer preferably contain at least one plasticizer.

[0025] The masking layer and / or transparent layer can be constructed using a single composite film or also using more than one composite film. The masking layer and / or transparent layer can be constructed using one or more stacked thermoplastic composite films, wherein the thickness of the thermoplastic intermediate layer is preferably 0.25 mm to 1 mm, typically 0.38 mm or 0.76 mm.

[0026] The masking layer and / or transparent layer can also be a functional thermoplastic interlayer, especially an interlayer with acoustic attenuation properties, an interlayer that reflects infrared radiation, an interlayer that absorbs infrared radiation, and / or an interlayer that absorbs UV (ultraviolet) radiation. For example, the transparent layer can also be a bandpass filter that blocks a narrow band of visible light.

[0027] The masking layer has at least one opaque area or is completely opaque. The opaque area is preferably made opaque by coloring or dyeing, preferably by dyeing with black. The coloring or dyeing of the opaque area of ​​the masking layer is of free choice, but is preferably black.

[0028] In another preferred embodiment of the composite sheet according to the invention, the masking layer is arranged at least adjacent to the lower edge of the composite sheet and preferably extends over at least 5% of the entire surface of the composite sheet, and particularly preferably over at least 10% of the entire surface of the composite sheet. In this example, the masking layer is preferably completely opaque. The masking layer is preferably arranged along and adjacent to the lower edge. When viewed from above, this creates a rectangular opaque strip arranged along the lower edge. For example, if the composite sheet is used as a windshield sheet in a vehicle, this arrangement enables a projection component with a high-contrast image in the masking layer area. Because the masking layer is arranged along the lower edge, the transparent area of ​​the composite sheet remains transparent.

[0029] In a particularly preferred embodiment of the invention, the opaque region of the masking layer is arranged in a frame-like manner around the edge region of the composite sheet, and particularly has a greater width in the section overlapping the reflective layer than in sections different from that section. The masking layer can be completely opaque. In this case, the transparent layer is preferably arranged within the opaque frame constructed by the masking layer. Alternatively, the region of the masking layer within the opaque frame is preferably transparent. In the sense of the invention, "having a greater width" means that the opaque region has a greater width perpendicular to the extension in that section than in other sections. In this way, the opaque region can be suitably adapted to the size of the reflective layer.

[0030] The reflective layer and the opaque region preferably each have equally arranged surfaces. Alternatively, the opaque region has a larger surface area than the reflective layer, and the reflective layer completely overlaps with the opaque region. Therefore, a high-contrast image can be obtained across the entire surface when light is reflected.

[0031] In the sense of this invention, a description such as element A and element B completely overlapping means that the orthogonal projection of the plane from element A to element B is completely arranged within element B.

[0032] In another particular embodiment of the invention, the reflective layer extends over at least 50%, preferably at least 70%, and particularly preferably at least 80% of the entire surface of the composite sheet. In particular, the reflective layer is arranged equidistantly over the entire surface of the composite sheet. This has the advantage that a large area of ​​the composite sheet is suitable for reflecting images. Multiple projection components can be provided, each generating a reflected image in a different area of ​​the composite sheet. If the composite sheet is used as a windbreak sheet, a head-up display area can be used in the perspective area of ​​the windbreak sheet. Simultaneously, a high-contrast reflected image can be generated in the overlapping area with the masking layer, which can also be visually perceived by the user.

[0033] The reflective layer is preferably partially translucent, which in the sense of the invention means that the reflective layer has an average transmittance of preferably at least 60%, particularly preferably at least 70%, and especially less than 85% in the visible spectrum (according to ISO 9050:2003), and therefore the visibility through the sheet is substantially unrestricted. The reflective layer preferably reflects at least 15%, particularly preferably at least 20%, and completely, particularly preferably at least 30%, of the light hitting the reflective layer. The reflective layer preferably reflects only p-polarized or s-polarized light. The reflective layer is configured to reflect light from the image display device. The light reflected by the reflective layer is preferably visible light, i.e., light in the wavelength range from about 380 nm to 780 nm. The reflective layer preferably has high and uniform reflectivity (at different angles of incidence) relative to p-polarized and / or s-polarized radiation, thereby ensuring high-intensity and color-neutral image presentation. Reflectivity describes the share of the total incident (light) radiation that is reflected. Reflectance is given as a percentage (relative to 100% of incident radiation) or as a unitless number from 0 to 1 (normalized to incident radiation). When described according to wavelength, this reflectance forms a reflection spectrum. The description of light reflection involves reflection measurements in the case of light source A, which radiates in the spectral range of 380 nm to 780 nm, where the radiation intensity is normalized to 100%. The share of radiation reflected by the reflective layer is measured, for example, using a spectrometer (e.g., PerkinElmer) and proportionally placed relative to the radiation intensity of light source A.

[0034] The reflective layer may also be opaque. The reflective layer is preferably opaque if the opaque areas of the reflective layer and the masking layer are arranged equally, or if the opaque areas of the reflective layer and the masking layer completely overlap. An opaque reflective layer preferably reflects at least 60%, particularly preferably at least 70%, and very preferably at least 80% of the light hitting the reflective layer.

[0035] The composite sheet according to the invention may additionally include a first masking strip, which is particularly made of dark, preferably black, enamel. The first masking strip is especially a peripheral, i.e., frame-like masking print. The peripheral first masking strip primarily serves as UV protection for the assembly adhesive used in the composite sheet. The first masking strip can be constructed opaquely and over its entire surface. The first masking strip can also be constructed at least partially translucent, for example, as a dot grid, strip grid, or square grid. Alternatively, the first masking strip can also have, for example, a gradient from opaque to translucent. Suitable methods for manufacturing the masking print and various variations of the masking print are known to those skilled in the art.

[0036] In addition to the first masking strip, there may be other masking strips, which may be designed independently of the first masking strip and constructed from the same materials and with the same structure as the first masking strip.

[0037] In a particularly preferred embodiment of the invention, a first masking strip is partially applied to the inner and / or outer side, preferably the inner side, of the outer sheet, wherein the heating element completely overlaps with the first masking strip. In other words, when viewed through the composite sheet in a direction from the outer sheet to the inner sheet, the heating element is completely covered by the first masking strip. Furthermore, an opaque masking layer or an opaque area of ​​the masking layer may completely or partially overlap with the first masking strip. With this arrangement, the heating element is invisible from the external environment, i.e., the environment facing the outer surface of the outer sheet. This improves the aesthetic properties of the composite sheet.

[0038] The explanation of polarization direction here refers to the plane of incidence of radiation on the composite sheet. P-polarized radiation is used to represent radiation whose electric field oscillates within the plane of incidence. S-polarized radiation is used to represent radiation whose electric field oscillates perpendicular to the plane of incidence. The plane of incidence is extended by the incident vector and the surface normal of the composite sheet at the geometric center of the irradiated area.

[0039] In other words, the proportions of polarization, particularly p- and s-polarized radiation, are determined at a point in the area irradiated by the image display device, preferably at the geometric center of the irradiated area. Since the composite sheet may be curved (e.g., when the composite sheet is constructed as a windproof sheet), this affects the incident plane of the radiation from the image display device, and therefore slightly different polarization proportions may appear in other areas, which is unavoidable due to physical reasons.

[0040] The reflective layer preferably comprises at least one metal selected from the group consisting of aluminum, tin, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, manganese, iron, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, or mixed alloys thereof. The reflective layer may also comprise silicon, either in combination with or independently of the aforementioned metals. Silicon can be readily deposited as a coating onto glass or a film using a spray coating process, which simplifies the fabrication of the reflective layer.

[0041] In a particularly preferred embodiment of the invention, the reflective layer is a cladding comprising a stack of thin layers, i.e., a sequence of thin individual layers. This stack of thin layers includes one or more silver-based conductive layers. The silver-based conductive layers impart basic reflective properties to the reflective cladding, as well as IR reflection effects and conductivity. The conductive layers are constructed based on silver. The conductive layers preferably contain at least 90% by weight of silver, particularly preferably at least 99% by weight of silver, and most preferably at least 99.9% by weight of silver. The silver layers may have dopants, such as palladium, gold, copper, or aluminum. Silver-based materials are particularly suitable for reflecting light, particularly preferably p-polarized light. The use of silver in the reflective layer has proven particularly advantageous in reflecting light. The thickness of the cladding is from 5 μm to 50 μm, and preferably from 8 μm to 25 μm.

[0042] If something is constructed "based on" a material, then it is mainly composed of that material, except for possible impurities or dopants, and in particular, it is essentially composed of that material.

[0043] The reflective layer can also be constructed as a coated or uncoated film that reflects light, preferably p-polarized light. The reflective layer can be a carrier film with a reflective coating or an uncoated reflective polymer film. The reflective coating preferably comprises at least one metal-based layer and / or a sequence of dielectric layers with alternating refractive indices. The metal-based layer preferably comprises or is composed of silver and / or aluminum. The dielectric layer can be based, for example, on silicon nitride, zinc oxide, tin-zinc oxide, silicon-metal mixed nitrides, such as zirconium silicon nitride, zirconium oxide, niobium oxide, hafnium oxide, tantalum oxide, tungsten oxide, or silicon carbide. The aforementioned oxides and nitrides can be deposited stoichiometrically, understoichiometrically, or overstoichiometrically. The oxides and nitrides can have dopants, such as aluminum, zirconium, titanium, or boron. The reflective uncoated polymer film preferably comprises or is composed of a dielectric polymer layer. The dielectric polymer layer preferably comprises PET. If the reflective layer is constructed as a reflective film, the reflective layer is preferably 30 μm to 300 μm thick, particularly preferably 50 μm to 200 μm thick, and especially 100 μm to 150 μm thick.

[0044] If the reflective layer is configured as a cladding, it is preferably applied to the inner sheet by physical vapor deposition (PVD), particularly preferably by cathodic spraying (“spraying”), and especially preferably by magnetic field-assisted cathodic spraying (“magnetron spraying”). However, in principle, the cladding can also be applied, for example, by chemical vapor deposition (CVD), plasma-assisted vapor deposition (PECVD), by vapor deposition, or by atomic layer deposition (ALD). The cladding is preferably applied to the sheet prior to lamination.

[0045] In a particular embodiment of the invention, a reflective layer is disposed on the outer side of the inner sheet, and a further reflective layer is additionally disposed on the inner side of the inner sheet. The reflective layer and the further reflective layer are arranged equidistantly in the viewing direction from the inner sheet to the outer sheet. Independent of the reflective layer, the further reflective layer may be made of the same material as the reflective layer and have the same structure as the reflective layer. By coating the outer and inner sides of the inner sheet, the total reflection of light hitting the reflective layer can be improved.

[0046] If a reflective coating is involved, it can also be manufactured using a coating method (vaporization coating or spraying) such as CVD or PVD.

[0047] In a particularly preferred embodiment of the invention, the reflective layer is a metal-free reflective film that reflects visible light beams, preferably p-polarized visible light beams. The reflective layer is a film that functions based on the cooperative interaction of a prism and a reflective polarizer. Such films for use with reflective layers are commercially available, for example, from 3M.

[0048] In another preferred embodiment of the invention, the reflective layer is a holographic optical element (HOE). An HOE is defined as an element based on the principle of holography. An HOE alters the light in the optical path by storing information typically stored as changes in refractive index in a hologram. Its function is based on the superposition of different planar or spherical light waves, the interference pattern of which causes the desired optical effect. HOEs have been used in transportation applications, for example, in head-up displays. Compared to simple reflective layers, the advantages of using HOEs arise from greater geometric design freedom in terms of the arrangement of the eye and projector positions, and, for example, the corresponding tilt angles of the projector and the reflective layer. Furthermore, in this variant, ghosting is particularly strongly reduced or even prevented. HOEs are suitable for presenting real images of varying widths or, however, virtual images of varying widths. Moreover, the geometric angles of the reflection can be adjusted using HOEs, so that, for example, when used in a vehicle, the information transmitted to the driver can be well presented from the desired viewing angle.

[0049] In a preferred embodiment of the invention, the reflective layer is configured as a coated or uncoated reflective film disposed between an opaque region of the masking layer and a transparent layer. The opaque region of the masking layer and the transparent layer partially overlap where the reflective layer is disposed. The transparent layer and the opaque region are constructed thinner in the overlapping region to prevent thickness variations in the composite sheet. The layer sequence in the region of the reflective layer is constructed as follows: -Outer sheet -Opaque area of ​​the masking layer -Reflective layer -Transparent layer -Inner sheet.

[0050] In another preferred embodiment, the composite sheet further includes a first current collector and a second current collector, configured for connection to a voltage source. The first and second current collectors are connected to the edge region of the heating element such that a current path for heating current through the heating element is formed between the current collectors. The first and second current collectors are preferably applied to the outer side of the inner sheet or the inner side of the outer sheet. The current collectors are particularly preferably arranged in the edge region of the composite sheet. The heating element and the first and second current collectors can be electrically connected to each other via wire. The wire preferably comprises or is made of copper and / or tungsten.

[0051] The current collector can be covered by the opaque area of ​​the masking layer, the first and / or the second masking strip toward the inner sheet and / or the outer sheet.

[0052] The first and second current collectors can be constructed as printed and baked conductive structures. The printed current collector preferably comprises at least one metal, metal alloy, metal compound, and / or carbon, particularly precious metals and especially silver. The printing paste preferably comprises metal particles, metal particles, and / or carbon, and especially precious metal particles, such as silver particles. Conductivity is preferably achieved through conductive particles. The particles can be in an organic and / or inorganic matrix, such as a paste or ink, preferably as a printing paste containing glass frit. Such current collectors are known to those skilled in the art.

[0053] The first and second current collectors can be connected to a voltage source via a connecting line. The connecting line is preferably a flat conductor (film conductor, flat strip conductor), which is based on a tin-plated copper, aluminum, silver, gold or its alloy.

[0054] The first and second current collectors are preferably connected to a voltage source that provides the on-board voltage common to motor vehicles, preferably from 12V to 15V and especially from about 14V. Alternatively, the voltage source may also have a higher voltage, preferably from 16V to 450V and especially from 40V to 100V.

[0055] The heating element may extend over the entire opaque area or may be arranged only partially within the opaque area. In the context of this invention, "opaque area" of the masking layer means that the heating element is completely surrounded by the opaque area of ​​the masking layer, i.e., in spatial contact with the opaque area of ​​the masking layer from all spatial directions. Preferably, the arrangement within the opaque area is achieved by arranging and laminating the heating element between at least two thermoplastic, at least partially opaque, composite films. Alternatively, the heating element may be embedded into at least one partially opaque thermoplastic composite film, preferably during the lamination process of forming the composite sheet according to the invention, by pressure and heat. The heating element may extend beyond the opaque area across the entire surface of the composite sheet.

[0056] Within the scope of this invention, the composite membrane can be a single membrane or a multilayer membrane, used to connect adjacent membranes, layers, sheets, etc.

[0057] In a particularly preferred embodiment of the invention, the heating element is completely embedded within the opaque region of the masking layer. Furthermore, the heating element preferably extends over the entire surface of the opaque region. Therefore, the heating element can be used to heat the entire opaque region and adjacent areas.

[0058] In a preferred embodiment of the invention, the heating element is arranged in the area where the reflective layer overlaps with the opaque area. The heating element is thus positioned behind the reflective layer when viewed through the composite sheet (starting from the inner sheet), so that the reflective layer completely covers the heating element. Alternatively, the reflective layer may only partially cover the heating element. This arrangement is particularly suitable when the reflective layer is, for example, arranged near the root of the sheet, i.e., near the lower edge of the composite sheet in its installed position. This is because condensation tends to condense, especially in this area, on the inner side of the inner sheet.

[0059] The heating element can be configured as a conductive coating applied to a carrier film. The carrier film is preferably based on a plastic structure, and particularly preferably based on a polyethylene terephthalate structure.

[0060] The conductive coating typically comprises one or more, for example, two, three, or four conductive functional layers. The functional layers preferably comprise at least one metal, such as silver, gold, copper, nickel, and / or chromium or a metal alloy. Particularly preferably, the functional layers comprise at least 90% by weight of metal, and especially at least 99.9% by weight. The functional layers can be composed of metal or metal alloys. Particularly preferably, the functional layers comprise silver or silver-containing alloys. Such functional layers exhibit particularly advantageous conductivity while maintaining high transmittance in the visible spectral range. The thickness of the functional layers is preferably from 5 nm to 50 nm, and particularly preferably from 8 nm to 25 nm. Within this range of thickness for the functional layers, high transmittance in the visible spectral range and particularly advantageous conductivity are advantageously achieved.

[0061] Preferably, at least one dielectric layer is disposed between two adjacent functional layers of the coating. Preferably, an additional dielectric layer is disposed below the first functional layer and / or above the last functional layer. The dielectric layer comprises at least one single layer made of a dielectric material, such as a nitride (e.g., silicon nitride) or an oxide (e.g., aluminum oxide). However, the dielectric layer may also comprise multiple single layers, such as a single layer of dielectric material, a smoothing layer, an adapter layer, a barrier layer, and / or an anti-reflective layer. The thickness of the dielectric layer is, for example, from 10 nm to 200 nm.

[0062] Such layered structures are typically obtained through a series of deposition processes performed on a carrier film using vacuum methods, such as magnetic field-assisted cathodic spraying.

[0063] Other suitable conductive coatings preferably include indium tin oxide (ITO), fluorine-doped tin oxide (SnO2:F), or aluminum-doped zinc oxide (ZnO:Al). The functional layer preferably has a thickness of 8 nm to 25 nm, particularly preferably 13 nm to 19 nm. This is particularly advantageous for the transparency, color neutrality, and areal resistivity of the conductive coating.

[0064] In an advantageous design, the conductive coating is a layer structure consisting of one or more individual layers with a total thickness of less than or equal to 2 μm, particularly preferably less than or equal to 1 μm.

[0065] The total thickness of all conductive layers is preferably 40 nm to 80 nm, and particularly preferably 45 nm to 60 nm. Within this range of total thickness, sufficiently high specific heating power P is advantageous, especially for transport vehicle sheets, particularly windshield sheets, given the typical spacing h between two current collectors and an operating voltage U in the range of 12 V to 15 V. Furthermore, the conductive coating exhibits particularly good reflectivity in the infrared range within this range of total thickness. If the total thickness of all conductive layers is too low, excessively high area resistivity R is generated. Quadrat This results in excessively low specific heating power P and reduced reflectivity for the infrared range.

[0066] In a particularly preferred embodiment of the invention, the heating element is constructed in the form of a thin heating wire, which is inserted at least into an opaque region of the masking layer. An advantage over conductive coatings is the relative simplicity of manufacturing and arrangement of the heating wire. For example, before joining sheets into a composite sheet, the heating wire can be placed on the surface of a thermoplastic composite film, which is configured as an opaque region for forming the masking layer of the composite sheet. During the manufacturing process of the composite sheet, the heating wire penetrates into the masking layer due to increased pressure and temperature. Depending on the thickness of the heating wire used, recesses can be cut into the masking layer using methods known to those skilled in the art (“cutter”), and the heating wire can be arranged within the recesses.

[0067] Alternatively, the heating wire can also be inserted into an opaque region of the thermoplastic interlayer, i.e., the masking layer, before connecting the outer and inner sheets, for example, by pressing in after the thermoplastic film has been heated. During the manufacturing process of the composite sheet, the heating wire can also be positioned between the two thermoplastic films. The heating wire preferably contains at least one metal, particularly preferably copper, tungsten, gold, silver, aluminum, nickel, manganese, chromium, and / or iron, as well as mixtures and / or alloys. The heating wire preferably has a thickness or diameter of 10 μm to 300 μm, particularly preferably 20 μm to 150 μm. This is particularly advantageous for the conductivity of the heating wire and the heat distribution in the composite sheet. The heating wire can be coated with an electrically insulating coating.

[0068] The heating wires are preferably arranged in a straight line within the opaque area of ​​the masking layer. Alternatively, the heating wires can be arranged partially or completely sinusoidally, zigzagly, zigzagly, or coiled, preferably zigzagly. Combinations of these arrangements are also possible. This means that, when viewed from above, the heating wires can extend through the composite sheet in a sinusoidal, zigzag, zigzag, or coiled manner. This arrangement allows for good heat distribution within the composite sheet. Furthermore, by artificially increasing the spacing between the current collectors, the desired heating power of the heating wires can be adjusted more precisely.

[0069] In a particular embodiment of the invention, a high-refractive-index coating is applied to the entire inner side or a region of the inner side of the inner sheet. The high-refractive-index coating is preferably in direct spatial contact with the inner side of the inner sheet. The high-refractive-index coating is hereby arranged at least in a region on the inner side of the inner sheet that completely overlaps with the reflective layer when viewed through the composite sheet. Therefore, compared to the high-refractive-index coating, the reflective layer is arranged spatially closer to the outer side of the outer sheet, but spatially farther from the inner side of the inner sheet. This means that light carrying a majority share of p-polarized light, preferably projected from the image display device onto the reflective layer, extends through the high-refractive-index coating before hitting the reflective layer.

[0070] The high-refractive-index coating has a refractive index of at least 1.7, more preferably at least 1.9, and very particularly preferably at least 2.0. The increased refractive index results in a high-refractive-index effect. The high-refractive-index coating causes a reduction in the reflection of light, especially p-polarized light, at the surface of the inner space side of the inner sheet, thereby allowing the desired reflection of the reflective coating to appear with higher contrast.

[0071] According to the inventors, this effect is based on the increased refractive index of the surface on the internal space side due to the high-refractive-index coating. This increases the Brewster angle α at the interface. Brewster Because the Brewster angle was determined to be Where n1 is the refractive index of air, and n2 is the refractive index of the material to which the radiation strikes. A high-refractive-index coating with a high refractive index results in an increased effective refractive index on the glass surface, and thus causes the Brewster angle to shift to a larger value compared to an uncoated glass surface. Therefore, in the common geometry of HUD-based projection components, the difference between the incident angle and the Brewster angle becomes smaller, thereby suppressing reflection of p-polarized light on the inner side of the inner sheet and reducing the resulting ghosting.

[0072] A high-refractive-index coating is preferably constructed from a single layer with no other layers below or above it. A single layer is sufficient to achieve good results and is technically simpler than applying a stack of layers. However, in principle, a high-refractive-index coating can also comprise multiple single layers, which may be desirable in individual cases for the optimization of specific parameters.

[0073] Within the scope of this invention, the refractive index is preferably given with respect to a wavelength of 550 nm. Methods for determining the refractive index are known to those skilled in the art. The refractive index given within the scope of this invention can be determined, for example, by means of ellipsometric analysis, wherein a commercially available ellipsometer (measuring instrument, such as a Sentech measuring instrument) can be used. Unless otherwise stated, the layer thickness or description of thickness relates to the geometric thickness of the layer.

[0074] Suitable materials for high-refractive-index coatings include silicon nitride (Si3N4), silicon-metal mixed nitrides (e.g., silicon-zirconium nitride (SiZrN), silicon-aluminum mixed nitrides, silicon-hafnium mixed nitrides, or silicon-titanium mixed nitrides), aluminum nitrides, tin oxide, manganese oxide, tungsten oxide, niobium oxide, bismuth oxide, titanium oxide, tin-zinc mixed oxides, and zirconium oxide. Additionally, transition metal oxides (e.g., scandium oxide, yttrium oxide, tantalum oxide) or lanthanide oxides (e.g., lanthanum oxide or cerium oxide) may also be used. The high-refractive-index coating preferably contains one or more of these materials or is based on their structure.

[0075] High-refractive-index coatings can be applied by physical or chemical vapor deposition, i.e., PVD or CVD coatings (PVD: Physical Vapor Deposition, CVD: Chemical Vapor Deposition). Suitable materials (preferably based on said materials to construct the coating) are in particular silicon nitride, silicon-metal mixed nitrides (e.g., silicon-zirconium nitride, silicon-aluminum mixed nitride, silicon-hafnium mixed nitride, or silicon-titanium mixed nitride), aluminum nitride, tin oxide, manganese oxide, tungsten oxide, niobium oxide, bismuth oxide, titanium oxide, zirconium oxide, zirconium nitride, or tin-zinc mixed oxides. High-refractive-index coatings are preferably applied by cathodic spraying (“sprayed”), especially by magnetic field-assisted cathodic spraying (“magnetron spraying”).

[0076] Alternatively, the high-refractive-index coating is a sol-gel coating. In the sol-gel method, a sol containing a coating precursor is first provided and allowed to mature. Maturation may include hydrolysis of the precursor and / or a (partial) reaction between the precursors. The precursor is typically present in a solvent, preferably water, an alcohol (especially ethanol), or a water-alcohol mixture. The sol preferably contains a silica precursor in the solvent. The precursor is preferably a silane, especially tetraethoxysilane or methyltriethoxysilane (MTEOS). However, alternatively, silicates may also be used as precursors, especially sodium silicates, lithium silicates, or potassium silicates, such as tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), tetraisopropyl orthosilicate, or organosilanes in general form R2nSi(OR1)4-n. Here, R1 is preferably alkyl, R2 is alkyl, epoxy, acrylate, methacrylate, amino, phenyl, or vinyl, and n is an integer from 0 to 2. Silicon halides or silanols can also be used. The silicon oxide precursor results in a sol-gel coating composed of silicon oxide. To increase the refractive index of the coating to that value, an additive to improve the refractive index is added to the sol, preferably titanium oxide and / or zirconium oxide, or precursors thereof. In the finished coating, the refractive index-improving additive is present in the silicon oxide matrix. The molar ratio of silicon oxide to the refractive index-improving additive can be freely chosen according to the desired refractive index, and is, for example, around 1:1.

[0077] If the reflective layer or the additional reflective layer is disposed on the inner side of the inner sheet, a high-refractive-index coating can also be applied to the reflective layer or the additional reflective layer. In particular, this arrangement is provided if the reflective layer is disposed on the outer side of the inner sheet and the additional reflective layer is disposed on the inner side of the inner sheet. The high-refractive-index coating improves the total reflection of light hitting the reflective layer and the additional reflective layer.

[0078] The outer and inner sheets preferably comprise or consist of glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass, aluminosilicate glass, or transparent plastic, preferably rigid transparent plastic, especially polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride, and / or mixtures thereof.

[0079] The outer and inner sheets may have other suitable coatings known by themselves, such as anti-reflective coatings, anti-stick coatings, scratch-resistant coatings, photocatalytic coatings, sun-protective coatings, or low-emissivity coatings.

[0080] The thickness of each sheet (outer and inner sheets) can vary widely and can be adapted to the requirements of individual cases. Preferably, sheets with a standard thickness of 0.5 mm to 5 mm, and more preferably 1.0 mm to 2.5 mm, are used. The size of the sheets can vary widely and depends on the application.

[0081] The composite sheet can have any three-dimensional shape. Preferably, the outer and inner sheets have no shaded areas, so that the outer and inner sheets can be coated, for example, by cathodic spraying. The outer and inner sheets are preferably flat or slightly or strongly curved in one or more spatial directions.

[0082] The invention further extends to a projection assembly comprising a composite sheet according to the invention and an image display device associated with a reflective layer. The image display device includes an image display pointing toward the reflective layer, the image of which is reflectible by the reflective layer and, after reflection, preferably exits the composite sheet according to the invention through the inside of an inner sheet, wherein at least a region of the reflective layer is illuminating the image display device, this region overlapping with an opaque region of a masking layer. A corresponding number of image display devices can be provided if multiple reflective layers are arranged staggered on their extensions.

[0083] The light emitted from the image display device is preferably visible light, that is, light in the wavelength range of about 380 nm to 780 nm.

[0084] According to a preferred design of the projection assembly according to the present invention, the image display, also referred to as a display, is constructed as a liquid crystal display (LCD), a thin-film transistor (TFT) display, a light-emitting diode (LED) display, an organic light-emitting diode (OLED) display, an electroluminescent (EL) display, a micro-LED display, a display based on light field technology, etc., preferably constructed as an LCD display. Due to the high reflectivity of p-polarized light, an energy-intensive projector is not required, as is commonly used in head-up display applications. The aforementioned display variants and other similar energy-efficient image display devices are sufficient. This results in reduced energy consumption and heat radiation.

[0085] In a preferred embodiment of the invention, at least 80% and preferably at least 90% of the light from the image display device is p-polarized. Alternatively, at least 80% and preferably at least 90% of the light from the image display device may be s-polarized.

[0086] Furthermore, the present invention extends to a method for manufacturing a composite sheet according to the invention. The method comprises the following steps in the given order: (a) The outer sheet, thermoplastic intermediate layer, heating element, reflective layer and inner sheet are arranged in a stacked manner.

[0087] A thermoplastic interlayer is arranged between the outer sheet and the inner sheet, and the heating element is arranged in the opaque area of ​​the masking layer.

[0088] The reflective layer is spatially positioned in front of the masking layer in the viewing direction from the inner sheet to the outer sheet, and at least partially overlaps with the opaque area of ​​the masking layer.

[0089] (b) Stacking and laminating the layers into a composite sheet.

[0090] The lamination of stacked layers is carried out under the action of heat, vacuum, and / or pressure, wherein the individual layers are connected to each other by at least one thermoplastic interlayer (lamination). Methods known per se can be used to manufacture composite sheets. For example, the so-called high-pressure laminar flow process can be performed for about 2 hours at an increased pressure of about 10 to 15 bar and a temperature of 130°C to 145°C. Vacuum bag or vacuum ring methods, also known per se, operate, for example, at about 200 mbar and 130°C to 145°C. The outer sheet, inner sheet, and thermoplastic interlayer can also be pressed into a composite sheet in a calender between at least one pair of rolls. This type of equipment is known for manufacturing composite sheets and typically has at least one heating passage before the press. The temperature during the pressing process is, for example, 40°C to 150°C. The combination of the calender and the high-pressure laminar flow method has been particularly proven in practice. Alternatively, a vacuum laminator can be used. The vacuum laminator consists of one or more heated and vacuum-ejectable chambers in which outer and inner sheets can be laminated within approximately 60 minutes under reduced pressure of 0.01 mbar to 800 mbar and at temperatures of 80°C to 170°C.

[0091] Furthermore, the invention extends to the use of the composite sheet according to the invention in vehicles used for land, air, or water transportation, particularly in motor vehicles, wherein the composite sheet can be used, for example, as a windshield sheet, rear sheet, side sheet, and / or roof sheet, preferably as a windshield sheet. Preferably, the composite sheet is used as a windshield sheet for a vehicle. The composite sheet according to the invention can also be used as a functional and / or decorative single piece, as well as as an integrated component in furniture, appliances, and buildings.

[0092] The invention is further extended to the use of a projection assembly according to the invention, the projection assembly comprising a composite sheet according to the invention and an image display device associated with a reflective layer. The image display device includes an image display pointing toward the reflective layer, whose image is reflected by the reflective layer and then preferably exits the composite sheet according to the invention through the inside of an inner sheet, wherein at least a region of the reflective layer is illuminated by the image display device, the region overlapping with an opaque region of a masking layer.

[0093] Different design schemes of the present invention can be implemented individually or in any combination. In particular, the features mentioned above and explained below can be used not only in the given combinations, but also in other combinations or individually, without departing from the scope of the present invention. Attached Figure Description

[0094] The invention is now explained in more detail with reference to the accompanying drawings. In the simplified, non-total-scale illustrations: Figure 1 A top view of an embodiment of the composite sheet according to the present invention is shown. Figure 1a The invention is shown to have Figure 1 A cross-sectional view of the projection assembly of the composite sheet in the image. Figure 2 Another cross-sectional view of a projection assembly having another embodiment of the composite sheet according to the invention is shown, and Figures 3-6 Enlarged cross-sectional views of different design schemes of the projection assembly according to the present invention are shown. Detailed Implementation

[0095] Figure 1 A top view of an embodiment of the composite sheet 1 according to the invention in a means of transport is shown in a highly simplified schematic diagram. Figure 1a This shows the projection component 100. Figure 1 Cross-sectional view of an embodiment. Figure 1a The cross-sectional view corresponds to the section line A-A' of composite sheet 1, as shown in... Figure 1 Like the simplified Chinese drawing.

[0096] The composite sheet 1 includes an outer sheet 2 and an inner sheet 3 together with a thermoplastic interlayer 4 disposed between the outer sheet and the inner sheets 2 and 3. The composite sheet 1 is installed in a vehicle and separates the interior space 14 of the vehicle from the external environment 15. For example, the composite sheet 1 is a windshield sheet for a motor vehicle.

[0097] The outer sheet 2 and the inner sheet 3 are both made of glass, preferably of heat-prestressed soda-lime glass, and are transparent to visible light. The thermoplastic interlayer 4 includes a masking layer 5 and a transparent layer 16.

[0098] The outer side I of the outer sheet 2 faces away from the thermoplastic interlayer 4 and is simultaneously the outer surface of the composite sheet 1. The inner side II of the outer sheet 2 and the outer side III of the inner sheet 3 face the interlayer 4, respectively. The inner side IV of the inner sheet 3 faces away from the thermoplastic interlayer 4 and is simultaneously the inner side of the composite sheet 1. It goes without saying that the composite sheet 1 can have any suitable geometry and / or curvature. As a composite sheet 1, the composite sheet typically has a convex arched portion. The composite sheet 1 also has an upper edge at the top in the mounting position and a lower edge at the bottom in the mounting position, as well as side edges on the left and right sides.

[0099] In the edge region 13 of the composite sheet 1, a frame-shaped surrounding first masking strip 7 is applied to the inner side II of the outer sheet 2. The first masking strip 7 is opaque and prevents the view of structures arranged inside the composite sheet 1, such as adhesive beads (Kleberaupe, sometimes also called adhesive tape or glue) used to bond the composite sheet 1 to the vehicle body. The first masking strip 7 is preferably black. The first masking strip 7 is made of a non-conductive material typically used for masking strips, such as baked black screen printing ink. The first masking strip 7 is arranged such that the masking layer 5 completely overlaps with the first masking strip. This means that when viewed through the composite sheet 1 from the external environment 15, the first masking strip covers the masking layer 5 and all other structures arranged behind the masking layer.

[0100] In addition, such as Figure 1 As shown in Figure A, the composite sheet 1 has a second masking strip 8 in the edge region 13 on the inner side IV of the inner sheet 3. The second masking strip 8 is constructed in a frame-like, surrounding manner. Like the first masking strip 7, the second masking strip 8 is made of a non-conductive material typically used for masking strips, such as baked black screen printing ink.

[0101] The transparent layer 16 is composed of a thermoplastic composite film, preferably of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and / or thermoplastic polyurethane (TPU). The transparent layer 16 extends planarly from the upper edge regions 13, 13'' (starting from the upper edge) along the upper and side edges over the largest area (e.g., 85% area) of the inner side II of the outer sheet 2 and the outer side III of the inner sheet 3. The transparent area of ​​the composite sheet 1 overlaps with the transparent layer 16. The transparent layer 16 is adjacent to the masking layer 5 in the lower region. The masking layer 5 is composed of an opaque thermoplastic composite film, preferably of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and / or thermoplastic polyurethane (TPU). For example, the masking layer 5 is colored black. The masking layer 5 extends planarly along the lower edge (in the edge regions 13, 13') and along the side edges of the composite sheet 1 until it is adjacent to the transparent layer 16. The transparent layer 16 and the masking layer 5 may slightly overlap (e.g., 5 mm) along the areas where they are adjacent.

[0102] A reflective layer 11 is partially disposed on the outer side III of the inner sheet 3. This reflective layer is deposited by vapor deposition using a PVD method. When viewed through the composite sheet 1 from the external environment 15, the reflective layer 11 is completely overlapped by the masking layer 5. Therefore, the reflective layer 11 is invisible when viewed from the external environment 15. Figure 1In the diagram, the area where the reflective layer 11 is disposed is indicated by a dashed line. The reflective layer 11 is disposed such that it is not obscured by the second masking strip 8 when viewed through the composite sheet 1 from the interior space 14 of the vehicle. In the example shown, the reflective layer 11 is disposed in a strip along the lower edge such that it is completely obscured by the mask layer 5 but not by the second masking strip 8. The reflective layer 11 is, for example, a metal cladding comprising at least one thin layer stack with at least one silver layer and a dielectric layer. Alternatively, the reflective layer 11 may also be configured as a reflective film and disposed on the outer side III of the inner sheet 3. The reflective film may comprise a metal cladding or, however, consist of a layered sequence of dielectric polymer layers.

[0103] The composite sheet 1 also includes a heating element 6 disposed within a masking layer 5. For example, during the manufacturing process, a heating element 2 is disposed between the outer sheet 2 and the masking layer 5. Due to pressure and heating during lamination, the heating element 6 is surrounded by the masking layer 5, so that in the illustrated embodiment, the heating element 6 is disposed closer to the inner surface II of the outer sheet 2 than the outer surface III of the inner sheet 3. The heating element 6 is constructed, for example, in the form of a heating wire. For example, the heating wire is based on a copper construction. The diameter of the heating wire 6 is, for example, approximately 100 μm. When viewed through the composite sheet 1 from the interior space 14 of the vehicle, the heating element 6 is disposed behind and largely covered by the reflective layer 11. The heating element 6 is generally orthogonal to the side edges and extends along the lower edge. The heating element 6 is not visible from the external environment 15 and the interior space 14 of the vehicle because the heating element is completely covered by the first masking strip 7 and by the masking layer 5.

[0104] For electrical contact, heating element 6 is connected to a first current collector in the left edge region of the heating element and to another second current collector in the right edge region of the heating element (in... Figure 1 and Figure 1a The material (not visible in the image) is connected and electrically connected. For example, the current collector contains silver particles, which are applied in a screen printing method and then baked. The length of the current collector roughly corresponds to the extension of the heating element 6 along the side edge of the composite sheet 1. When a voltage is applied to the current collector, a uniform current flows through the heating element 6 between the current collectors. The current collector is connected to a voltage source via an input line, which provides the on-board voltage commonly used in motor vehicles, preferably 12V to 15V, for example, about 14V. Alternatively, the 14V voltage source can also have a higher voltage, for example from 35V to 45V, and especially 42V. When current flows through the heating element 6, the heating wire is heated due to its resistance and Joule thermal development. Therefore, the area of ​​the composite sheet 1 in which the heating element 6 is arranged can be smoothly and energy-efficiently protected from icing and condensation.

[0105] The projection assembly 100 also includes an image display device 10 arranged in the dashboard 9 as an imager. The image display device 10 generates light 12 (image information) directed toward the reflective layer 11 and reflected by the reflective layer 11 as reflected light 12' into the vehicle interior space 14, where the reflected light can be seen by an observer, such as the driver. The reflective layer 11 is configured to reflect the light 12 of the image display device 10, i.e., the image of the image display device 10. The light 12 of the image display device 10 preferably strikes the composite sheet 1 at an angle of incidence of 50° to 80°, particularly 60° to 70°, typically about 65°, as is common in HUD projection assemblies. If the reflective layer 11 is positioned appropriately for this purpose, the image display device 10 can also be arranged, for example, in the A-pillars or on the roof of the vehicle (on the vehicle interior side, respectively). If multiple reflective layers 11 are provided, each reflective layer 11 can be associated with a separate image display device 10, i.e., multiple image display devices 10 can be arranged. The image display device 10 is, for example, a display such as an LCD display, an OLED display, an EL display, a μLED display, etc. Alternatively, the composite sheet 1 may be a top sheet, a side sheet, or a back sheet.

[0106] Figure 2 The variant shown is basically corresponding to Figure 1 and 1a The variations in [the text] are discussed here, but only the differences are considered, and further references should be made to [other aspects]. Figure 1 and 1a The description.

[0107] and Figure 1 and 1a The difference shown is not the same. Figure 2 The reflective layer 11 extends across the entire outer surface III of the inner sheet 3 and is applied thereon. However, unlike what is shown here, the reflective layer 11 may also be applied to the inner surface IV of the inner sheet 3. The reflective layer 11 is, for example, a metallic cladding comprising at least one thin layer stack with at least one silver layer and a dielectric layer. The reflective layer 11 is configured to be partially translucent, such that it reflects approximately 30% of the light 12 hitting the reflective layer and has approximately 70% transmittance for the light 12.

[0108] In this embodiment, the thermoplastic intermediate layer 4 is uniquely composed of the masking layer 5, and... Figure 1 and 1aIn contrast, the masking layer is not only arranged in the edge region 13' of the composite sheet 1 between the outer sheet 2 and the inner sheet 3, but is equally arranged on the entire inner side II of the outer sheet 2 and the outer side III of the inner sheet 3. The masking layer 5 here has a transparent region 5'' and an opaque region 5'. Although it involves a composite film bonded together before lamination, the composite film is constructed, for example, based on polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), and / or thermoplastic polyurethane (TPU), but the composite film is colored in the frame-shaped surrounding region 5' of the masking layer 5. For example, the color is black. And the region 5'' of the masking layer 5 within the frame-shaped surrounding section 5' is transparent and therefore suitable for see-through. The thickness of the masking layer 5 is, for example, 0.76 mm. When seen through the composite sheet 1, the first masking strip 7 is applied equally to the inner surface II of the inner sheet with the opaque region 5' of the masking layer 5.

[0109] The opaque region 5' of the masking layer 5 is widened in the lower (engine-side) section 13' of the edge region 13, that is, the opaque region 5' is wider in the lower (engine-side) section 13' of the edge region 13 and in the upper (roof-side) section 13'' of the edge region 13 of the composite sheet 1 (and in Figure 2 The lateral section of the edge area 13 that is not visible in the middle has a larger width compared to the inner sheet and outer sheets 2 and 3. "Width" is understood as the dimension of the opaque area 5' perpendicular to the lower edge of the inner sheet and outer sheets 2 and 3.

[0110] In this embodiment, the heating element 6 may also be arranged in the upper top side section 13' within the opaque region 5' of the masking layer 5. Additionally, in order to achieve a circumferential heating effect, the heating element 6 may also be arranged along the side edge region and in the side edge region in the extending direction from the upper edge to the lower edge.

[0111] Furthermore, multiple image display devices 10 may be provided, which, for example, illuminate the lower (engine-side) section 13' and the upper (roof-side) section 13'' of the edge region 13 with visible light 12. For example, the image display devices 10 can be arranged such that a (partially) surround, high-contrast image is produced.

[0112] Since the reflective layer 11 extends over the entire outer side III of the inner sheet 3, all areas of the composite sheet 1 can be used to reflect images. Additional image display devices can be used, for example, to illuminate areas of the reflective layer 11 that do not overlap with the opaque area 5' of the masking layer 5, i.e., within the transparent area of ​​the composite sheet 1. Therefore, the functionality of a head-up display can be used.

[0113] Now for reference Figures 3 to 6The diagram shows enlarged cross-sectional views of different designs of composite sheet 1. Figure 1a As shown, Figures 3 to 6 The cross-sectional view corresponds to the section line A-A' in the lower section 13' of the edge region 13 of the composite sheet 1.

[0114] Figure 3 Show Figure 1a An enlarged cross-sectional view of the edge region 13'. Figure 3 In the variant of the composite sheet 1 shown, a completely opaque masking layer 5 is arranged between the outer sheet 2 and the inner sheet 3. In the example shown, the masking layer 5 is in direct material contact with the reflective layer 11 and the first masking strip 7. The reflective layer 11 is arranged on the outer side III of the inner sheet 3. Light 12 of the image display device 10 is reflected as reflected light 12' from the reflective layer 11 into the interior space 14 of the vehicle. The light 12, 12' can have s-polarization and / or p-polarization. Since the incident angle of light 12 on the composite sheet 1 is close to the Brewster angle, the p-polarized portion of light 12 is hardly blocked in terms of transmission through the inner sheet 3. This variant has the advantage that a relatively large portion of the incident p-polarized light 12 is reflected and then, since the incident angle is equal to the exit angle (in Figures 3 to 6 (As shown by α) This fact allows the image to be transmitted into the interior space 14 of the vehicle essentially unobstructed by the inner sheet 3. Furthermore, the image is well-recognizable against the background of the opaque masking layer 5 with high contrast. The heating element 5 is not visually perceptible from the external environment 15 due to the first masking strip 7. Additionally, the heating element is not visually perceptible from the interior space 14 of the vehicle due to the opaque masking layer 5.

[0115] The heating wires of the heating element 6 are arranged within an opaque masking layer 5 with their extension direction orthogonal to the cross-sectional plane. The individual heating wires are spaced apart from each other, for example, by a spacing of approximately 1 mm, from the lower section to the upper section of the enlarged cross-section.

[0116] Figures 4 to 6 The variant shown is basically corresponding to Figure 1 ,1a and Figure 3 Variations of [the original text], therefore only the differences will be discussed here, and reference will be made elsewhere to [the relevant information]. Figure 1 and 2 The description.

[0117] and Figure 3 The difference shown is that in Figure 4In this configuration, the reflective layer 11 is not applied to the outer side III of the inner sheet 3, but rather to the inner side IV of the inner sheet 3. This variation has the advantage that the incident light 12 is not obstructed by transmission through the inner sheet 3. Furthermore, this is also preferably suitable for light 12 with a high s-polarization fraction, as it produces less ghosting caused by reflection at the inner sheet 3.

[0118] Figure 5 The variation of the composite sheet 1 shown is similar to Figure 3 The only difference in the variant is that a high-refractive-index coating 17 is arranged on the inner side IV of the inner sheet 3. The high-refractive-index coating 17 is applied, for example, by means of a sol-gel method and is composed of a titanium oxide coating. Due to the higher refractive index (e.g., 1.7) of the high-refractive-index coating 17 compared to the inner sheet 3, the Brewster angle (for soda-lime glass), which is normally around 56.5°, can be changed. This simplifies the application and reduces the interference of ghosting caused by reflections through the inner side IV of the inner sheet 3.

[0119] Figure 6 The variation of the composite sheet 1 shown is similar to Figure 3 The variation differs in that, in addition to the first reflective layer 11' on the outer side III of the inner sheet 3, an additional reflective layer 11'' is arranged on the inner side IV of the inner sheet 3. Furthermore, a high-refractive-index coating 17 is applied to this additional reflective layer 11''. This arrangement provides significant advantages when the reflective layers 11', 11'' each individually reflect a small portion (<10%) of the incident light 12. The overall reflection of the incident light 12 is improved by arranging them not only on the outer side III of the inner sheet 3 but also on the inner side IV of the inner sheet 3. The high-refractive-index coating 17 also helps to avoid interfering ghosting caused by reflections at the inner side IV of the inner sheet 3.

[0120] In all embodiments, the reflective layer 11 is arranged on the vehicle interior space side of the masking layer 5, that is, when viewed toward the inside of the composite sheet 1, the reflective layer 11 is in front of the masking layer 5.

[0121] As described above, this invention provides an improved composite sheet for projection components, achieving excellent image presentation with high contrast. Undesirable sub-images can be avoided. Because the heating element is used in conjunction with the composite sheet, the space in the dashboard area can be significantly reduced when installed in a vehicle, enabling the possibility of thinner designs for the vehicle's interior. Image presentation via a reflective layer before the masking layer can replace displays typically mounted on the dashboard, such as speedometers, tachometers, warning indicators, and fuel tank displays. Heating the composite sheet by the heating element replaces the input conduit that typically guides air heated by engine heat to the windshield sheet. Furthermore, by eliminating air exhaust nozzles that are typically positioned in a specific geometry relative to the glass assembly, additional geometric freedom is gained in the design of the vehicle's interior. The composite sheet according to the invention can be manufactured simply and cost-effectively using known manufacturing methods.

[0122] List of reference numerals 1 Composite sheet 2 outer sheets 3 inner sheets 4 thermoplastic intermediate layer 5 layers of shielding 5' opaque area 5'' transparent area 6 heating elements 7 First Covering Clause 8 Second Covering Article 9-Dashboard 10 Image Display Devices 11 reflective layer 12,12' light 13,13',13'' Edge region 14. Interior space of transportation vehicles 15 External Environment 16 transparent layers 17 High Refractive Index Coating 100 projection components The outer side of the outer sheet 2 II. Inner side of outer sheet 2 The outer side of inner sheet 3 of III The inner side of IV inner sheet 3 A-A' section line.

Claims

1. A composite sheet (1) for use in a projection assembly (100), the composite sheet comprising at least: -Outer sheet (2), inner sheet (3) and thermoplastic interlayer (4) disposed between the outer sheet (2) and the inner sheet (3), The outer sheet (2) and the inner sheet (3) each have an outer side (I, III) and an inner side (II, IV), and the inner side (II) of the outer sheet (2) and the outer side (III) of the inner sheet (3) face each other. The thermoplastic intermediate layer (4) includes at least one masking layer (5), and the masking layer (5) is opaque in at least one region (5'). - A heating element (6) is arranged within an opaque region (5') of the masking layer (5), wherein the heating element (6) is completely surrounded by the opaque region (5') of the masking layer (5), and - A reflective layer (11), which is suitable for reflecting visible light (12). The reflective layer (11) is spatially arranged in front of the masking layer (5) in the viewing direction from the inner sheet (3) to the outer sheet (2) and at least partially overlaps with the opaque area (5') of the masking layer (5).

2. The composite sheet (1) according to claim 1, wherein, The thermoplastic intermediate layer (4) is composed of at least one masking layer.

3. The composite sheet (1) according to claim 1, wherein, The masking layer (5) also has a transparent area (5'') and the opaque area (5') extends over 30% of the entire surface of the composite sheet (1).

4. The composite sheet (1) according to claim 3, wherein, The opaque area (5') extends over 20% of the entire surface of the composite sheet (1).

5. The composite sheet (1) according to claim 3, wherein, The opaque area (5') extends over 10% of the entire surface of the composite sheet (1).

6. The composite sheet (1) according to claim 1, wherein, The thermoplastic intermediate layer (4) includes the masking layer (5) and the transparent layer (16), and the masking layer (5) is completely opaque.

7. The composite sheet (1) according to claim 6, wherein, The masking layer extends over 30% of the entire surface of the composite sheet (1).

8. The composite sheet (1) according to claim 7, wherein, The masking layer extends over 20% of the entire surface of the composite sheet (1).

9. The composite sheet (1) according to claim 7, wherein, The masking layer extends over 10% of the entire surface of the composite sheet (1).

10. The composite sheet (1) according to any one of claims 1 to 8, wherein, The masking layer (5) is arranged adjacent to at least the lower edge of the composite sheet (1).

11. The composite sheet (1) according to claim 10, wherein, The masking layer (5) extends over at least 5% of the entire surface of the composite sheet (1).

12. The composite sheet (1) according to claim 10, wherein, The masking layer (5) extends over at least 10% of the entire surface of the composite sheet (1).

13. The composite sheet (1) according to any one of claims 1 to 9, wherein, The opaque area (5') of the masking layer (5) is arranged in a frame-like manner around the edge area of ​​the composite sheet (1).

14. The composite sheet (1) according to claim 13, wherein, The opaque region (5') of the masking layer (5) has a greater width in the section (13') that overlaps with the reflective layer (11) than in the section (13'') that is different from that section.

15. The composite sheet (1) according to any one of claims 1 to 9, wherein, - The reflective layer (11) and the opaque region (5') each have equally arranged surfaces, or - The opaque region (5') has a larger surface area than the reflective layer (11), and the reflective layer (11) completely overlaps with the opaque region (5').

16. The composite sheet (1) according to any one of claims 1 to 9, the composite sheet further comprising a first masking strip (7), the first masking strip being partially applied to the inner side (II) of the outer sheet (2), and wherein, At least the heating element (6) completely overlaps with the first shielding strip (7).

17. The composite sheet (1) according to any one of claims 1 to 9, wherein, The reflective layer (11) has an average transmittance of at least 60% in the visible spectrum.

18. The composite sheet (1) according to claim 17, wherein, The reflective layer (11) has an average transmittance of at least 70% in the visible spectrum.

19. The composite sheet (1) according to claim 17, wherein, The reflective layer (11) has an average transmittance of less than 85% in the visible spectrum.

20. The composite sheet (1) according to any one of claims 1 to 9, wherein, The reflective layer (11) reflects at least 15% of the light (12) that hits the reflective layer (11).

21. The composite sheet (1) according to claim 20, wherein, The reflective layer (11) reflects at least 20% of the light (12) that hits the reflective layer (11).

22. The composite sheet (1) according to claim 20, wherein, The reflective layer (11) reflects at least 30% of the light (12) that hits the reflective layer (11).

23. The composite sheet (1) according to any one of claims 1 to 9, further comprising a first current collector and a second current collector, the first current collector and the second current collector being configured for connection to a voltage source, in, The first and second current collectors are connected to the edge region of the heating element (6) such that a current path for heating current through the heating element (6) is formed between the current collectors.

24. The composite sheet (1) according to any one of claims 1 to 9, wherein, The heating element (6) is completely embedded in the opaque region (5') of the masking layer (5).

25. The composite sheet (1) according to any one of claims 1 to 9, wherein, The heating element (6) is constructed in the form of a heating wire.

26. The composite sheet (1) according to claim 25, wherein, The heating wire has a diameter of 10 μm to 300 μm.

27. The composite sheet (1) according to claim 25, wherein, The heating wire has a diameter of 20 μm to 150 μm.

28. The composite sheet (1) according to claim 25, wherein, The heating wire contains metal.

29. The composite sheet (1) according to claim 28, wherein, The heating wire is made of metal.

30. The composite sheet (1) according to claim 28, wherein, The heating wire contains copper and / or tungsten.

31. The composite sheet (1) according to claim 30, wherein, The heating wire is made of copper and / or tungsten.

32. The composite sheet (1) according to any one of claims 1 to 9, wherein, A high-refractive-index coating (17) having a refractive index of at least 1.7 is disposed at least in the region of the inner side (IV) of the inner sheet (3) that overlaps with the reflective layer (11), and wherein the high-refractive-index coating (17) is always spatially disposed in front of the reflective layer (11) when the inner side (IV) of the inner sheet (3) is observed.

33. A projection assembly (100), comprising: - The composite sheet (1) according to any one of claims 1 to 32, - An image display device (10) associated with the reflective layer (11), the image display device having an image display facing the reflective layer (11), the image of the image display being reflectable by the reflective layer (11), Among them, at least the area of ​​the reflective layer (11) that overlaps with the opaque area (5') of the masking layer (5) can be illuminated by the image display device (10).

34. A method for manufacturing a composite sheet (1) according to any one of claims 1 to 32, wherein: (a) The outer sheet (2), thermoplastic intermediate layer (4), heating element (6), reflective layer (11) and inner sheet (3) are arranged in a stacked manner. The thermoplastic intermediate layer (4) is arranged between the outer sheet (2) and the inner sheet (3), and the heating element (6) is arranged within the opaque area (5') of the masking layer (5). The reflective layer (11) is spatially arranged in front of the masking layer (5) in the viewing direction from the inner sheet (3) to the outer sheet (2) and at least partially overlaps with the opaque region (5') of the masking layer (5). (b) The obtained layers are stacked and laminated into a composite sheet (1).

35. Use of a composite sheet (1) according to any one of claims 1 to 32 in a means of transport for land, air or water transportation.

36. The use according to claim 35, wherein, The composite sheet (1) is used as a windshield sheet for transportation vehicles.

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