Composite pane with masking layer and electrically switchable functional foil
Patent Information
- Application Number
- EP2023761139
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-08-30
- Filing Date
- 2023-08-25
- Publication Date
- 2025-07-09
AI Technical Summary
Head-up displays in vehicles face challenges with reduced contrast and visibility due to superimposed external light, especially in varying weather and lighting conditions, as the windshield area intended for reflection must maintain high transparency, leading to poorer perceptibility of safety-relevant information.
A composite pane with a thermoplastic intermediate layer, a masking layer, and an electrically switchable functional film that can change its optical transparency by applying a voltage, combined with a reflection layer applied only in specific areas, allowing for adjustable opaque regions to enhance contrast and visibility.
The solution provides adjustable opaque areas to optimize visibility and contrast, ensuring safety-relevant information is clearly visible in all conditions while allowing maximum transparency when needed, thus enhancing road safety and reducing unwanted secondary images.
Smart Images
Figure 1.1
Abstract
Description
[0001] Composite pane with masking layer and electrically switchable functional film
[0002] The invention relates to a composite pane with a partially applied reflective layer and a masking layer in combination with an electrically switchable functional film, a method for its production and its use, as well as a projection arrangement.
[0003] Modern automobiles are increasingly being equipped with so-called head-up displays (HIDs). Using a projector, typically located in the dashboard, images are projected onto the windshield, reflected there, and perceived by the driver as a virtual image behind the windshield. This allows important information to be projected into the driver's field of vision, such as the current speed, navigation information, or warnings, which the driver can perceive without having to take their eyes off the road. Head-up displays can thus significantly contribute to improving road safety.
[0004] However, head-up displays often have the problem that the area of the windshield intended to reflect the light projected by the projector must have a high transparency of at least 70%. The reflected light from the projector is therefore overlaid by light from the outside environment, which, depending on the lighting conditions, can lead to a reduction in the contrast of the virtual image and thus to poorer visual perception for the driver. Adequate visual perception of safety-relevant information, such as lane departure warnings, speedometer, or engine speed, must be ensured in all weather and lighting conditions.It would be desirable to have a projection arrangement based on head-up display technology that does not produce any unwanted side images and whose arrangement is relatively easy to accomplish while ensuring good visibility and sufficient brightness and contrast of the displayed image information. To achieve this, it is necessary to increase the contrast in the reflective area of the windshield. The contrast increase can be achieved, for example, by making the background of the reflective area largely or completely opaque. Such solutions require that a reflective layer be applied only in a locally limited area of the windshield. The application of metallic coatings to glass panes is usually achieved by sputtering, in particular magnetron sputtering. During sputtering, atoms are released from a target by bombarding it with ions.Using physical vapor deposition, the glass pane is coated with atoms released from the target in an evacuated chamber. Guided by electric fields, the atoms move through the chamber toward the glass pane. They move from the cathode, on which the target is located, to the anode. Due to the positioning of the glass pane between the cathode and anode, the layer forms on the glass pane. In the case of magnetron sputtering, an additional magnetic field is placed behind the cathode, which leads to faster layer growth and a denser, i.e., less porous, layer. Processes in which sputtering is used to coat glass panes are known, for example, from WO 9900528 A1, DE 10126868 C1, and WO 2017198363 A1.
[0005] Magnetron sputtering is also suitable for coating glass panes because, unlike many other coating technologies, it can also be used on curved glass panes, as is the case with panes intended for the automotive sector, for example. Selective coating of only certain surface areas can be achieved, for example, by masking the areas that are not to be coated.
[0006] Cold gas spraying is also a suitable method for coating glass panes and is a coating process generally known to those skilled in the art. It involves applying a powder to a substrate at very high speed. Methods for coating using cold gas spraying are known, for example, from WO 2010 / 003396 A1, EP 3 845685 A1, and EP 2902530 A1.
[0007] A reflective layer in the masking layer area enables good visibility of the virtual image with high contrast and appropriate brightness. Currently, the dimensions of the masking layer and reflective layer are fixed during manufacturing, preventing any variability in the opaque area in practical applications.
[0008] The present invention is based on the object of providing an improved composite pane with a partially applied reflective layer, which overcomes the aforementioned disadvantage. In particular, the composite pane should be easy and reliable to manufacture in industrial series production.
[0009] The object of the present invention is achieved by a composite pane according to claim 1. Preferred embodiments are evident from the subclaims.
[0010] The composite pane according to the invention comprises an outer pane, a thermoplastic intermediate layer, at least one masking layer, and an inner pane. The thermoplastic intermediate layer is arranged between the outer pane and the inner pane. The masking layer is arranged between the outer pane and the inner pane.
[0011] The composite pane further comprises at least one electrically switchable functional film with a functional layer that can be switched between a first switching state with lower optical transmission and a second switching state with higher optical transmission by applying an operating voltage. According to the invention, the electrically switchable functional film is arranged, when viewed vertically through the composite pane, directly adjacent to the masking layer or overlapping an opening in the masking layer, wherein the masking layer and the switchable functional film are arranged in one region of the composite pane.
[0012] Furthermore, the composite pane comprises at least one reflective layer for reflecting light on the outside surface and / or on the inside surface of the inner pane, wherein the reflective layer, when viewed perpendicularly through the composite pane, is arranged entirely in the aforementioned region of the composite pane in which the masking layer and the switchable functional film are arranged.
[0013] If the electrically switchable functional film is directly adjacent to the masking layer, the dimensions of the opaque region of the composite pane, as defined by the masking layer, can be optionally expanded. The opaque region of the composite pane is preferably expanded seamlessly by the electrically switchable functional film in the first switching state. If the electrically switchable functional film is arranged to overlap an opening in the masking layer, the dimensions of the opaque region of the composite pane, as defined by the masking layer, can be optionally expanded, wherein the opening in the masking layer can be made opaque by the electrically switchable functional film in the first switching state. For this purpose, the electrically switchable functional film completely covers the opening in the masking layer when viewed perpendicularly through the composite pane.The electrically switchable functional film thus complements the masking layer in the first switching state, thereby enlarging the opaque area of the laminated pane. In other words, the masking layer and the electrically switchable functional film are used in combination to arbitrarily change the size of the opaque area of the laminated pane. In the first switching state of the electrically switchable functional film, the opaque area of the laminated pane results from the combination of the opaque areas of the masking layer and the electrically switchable functional film, based on a perpendicular view through the laminated pane. In the second switching state, the opaque area of the laminated pane results from the masking layer alone.
[0014] The electrically switchable functional film advantageously allows the dimensions of the opaque region of the composite pane to be changed when it is in the first switching state with lower optical transmission, i.e., the opaque region is enlarged. On the other hand, the dimensions of the opaque region of the composite pane can be reduced to those of the masking layer when it is in the second switching state with higher optical transmission, i.e., the opaque region of the composite pane is reduced. In this way, the size of the opaque region of the composite pane can be arbitrarily enlarged or reduced by electrically switching the electrically switchable functional film, and thus specifically adapted to the respective requirements.For example, in certain driving situations of a motor vehicle, such as parking, it may be desirable to have as large a transparent area of the windshield as possible, whereas in other driving situations, for example when the vehicle is stationary or during autonomous driving, it may be desirable to display as much information as possible with high contrast, so that the opaque area should be as large as possible.
[0015] The electrically switchable functional film thus serves to enlarge the dimension of the opaque region of the composite pane when the electrically switchable functional film is in the first switching state, while, on the other hand, leaving the opaque region unchanged when it is in the second switching state. For this purpose, the switchable functional film is opaque to visible light in the first switching state and transparent in the second switching state. For the purposes of the present invention, "transparent" means that the transmission for visible light is more than 30%. Accordingly, "opaque" means a light transmission of less than 5%, preferably less than 1.5%, in particular at most 0.1%, for example 0%. Particularly preferably, the switchable functional film has an optical transmission of less than 1.5% in the first switching state and an optical transmission of more than 30% in the second switching state.The electrically switchable functional film is opaque in the first switching state with lower optical transparency and transparent in the second switching state with higher optical transparency.
[0016] Electrically switchable functional films whose optical transparency can be changed are well known to those skilled in the art and are commercially available. These are generally planar electro-optical functional elements with a functional layer (active layer) between two planar electrodes, wherein the optical transparency of the functional layer is electrically adjustable. This means that the optical transparency of the functional film or functional layer can be controlled by applying an electrical voltage (operating voltage), whereby the functional layer is generally opaque without electrical voltage and transparent with electrical voltage. The applied voltage can thus be used to control the transmission of visible light through the electro-optical functional element, although such an adjustment of the optical properties generally does not allow for independent illumination of the composite panes.
[0017] The electrical contacting of functional layers is usually achieved via busbars, which are applied to the edge of the functional layer and provide electrical contact. By connecting the busbars to an external voltage source, typically via flat conductors attached to the busbars, a voltage is applied and the functional layer is switched.
[0018] In principle, any electrically switchable functional film can be used whose optical transparency can be changed by applying an operating voltage and can be switched between an opaque switching state and a transparent switching state. The electrically switchable functional film is preferably a guest-host functional film, an electrochromic functional film, an SPD functional film, or a PDLC functional film. Such functional films are easy to laminate into laminated panes. In particular, electro-optical functional films with a liquid crystal-based functional layer, which are based on the so-called "guest-host" effect, represent an interesting option for implementing an electro-optical switching function in a laminated pane in a simple, space-saving, cost-effective, and reliable manner.Here and in the following, electro-optical functional films with a liquid crystal-based functional layer based on the "guest-host" effect are referred to simply as "guest-host functional films." Guest-host functional films typically comprise a nematic liquid crystal (host) provided with an additive (guest), for example, dichroic dye molecules that absorb light anisotropically. Since the additive molecules have an elongated shape, their orientation can be controlled by the orientation of the liquid crystal molecules, i.e., the host. This is achieved in practice by applying an electric field to the liquid crystal. In this way, the optical transparency of the guest-host functional film can be very precisely controlled by an external electric field.Guest-host functional films with a functional layer made of a liquid crystalline material with an embedded additive are well known to those skilled in the art, so they need not be discussed in detail here. Guest-host functional films are commercially available, for example, under the term "Light Control Film," for example, from Dai Nippon Printing Co., Ltd., Japan, under the product name LCF005(EU).
[0019] Electrochromic functional films are known, for example, from US 20120026573 A1 and WO 2012007334 A1. SPD functional films (SPD = Suspended Particle Device) are known, for example, from EP 0876608 B1 and WO 2011033313 A1. PDLC functional films (PDLC = Polymer Dispersed Liquid Crystal) are known, for example, from DE 102008026339 A1. Such functional films are frequently used in the industrial series production of laminated glass and are well known to those skilled in the art, so they need not be discussed in detail here.
[0020] The composite pane according to the invention is generally intended to separate the interior of a vehicle window from the outside environment. For the purposes of the invention, the inner pane refers to the pane of the composite pane facing the vehicle interior. The outer pane refers to the pane facing the outside environment. The composite pane has, in particular, an upper edge and a lower edge, as well as two side edges running between them. The upper edge refers to the edge which is intended to point upwards in the installed position. The lower edge refers to the edge which is intended to point downwards in the installed position. In the case of a windshield, the upper edge is often also referred to as the roof edge and the lower edge as the engine edge.
[0021] The outer pane and the inner pane each have an outer side and an inner side surface and a circumferential side edge running between them. For the purposes of the invention, the term outer surface refers to the main surface which is intended to face the outside environment in the installed position. For the purposes of the invention, the term inner side surface refers to the main surface which is intended to face the interior in the installed position. The interior side surface of the outer pane and the outer side surface of the inner pane face each other and are connected to one another by the thermoplastic intermediate layer. The outer side surface of the outer pane is referred to as side I. The interior side surface of the outer pane is referred to as side II. The outer side surface of the inner pane is referred to as side III.The interior surface of the outer pane and the exterior surface of the inner pane face each other.
[0022] According to the invention, at least one reflective layer for reflecting light is arranged on the outer surface and / or on the inner surface of the inner pane. Thus, a single reflective layer can be provided, arranged on the outer surface of the inner pane or on the inner surface of the inner pane. Alternatively, two reflective layers can be provided, arranged on the outer surface and on the inner surface of the inner pane.
[0023] When the composite pane is installed in a vehicle, the reflective layer is closer to the vehicle interior than the masking layer, so that the imaging unit of a projection arrangement arranged in the vehicle interior has a direct view of the reflective layer and the reflective layer can reflect light emitted by the imaging unit (virtual image). The reflective layer is arranged in an area of the composite pane which, when viewed perpendicularly through the composite pane, lies entirely within the area in which the masking layer and the electrically switchable functional film are arranged. Thus, when viewed perpendicularly through the composite pane or in orthogonal projection through the composite pane, the reflective layer is arranged in overlap with the combination of masking layer and electrically switchable functional film.In other words, the reflective layer thus has no section that does not overlap the combination of masking layer and electrically switchable functional film. This means that the reflective layer is only formed where it is located in front of the combination of masking layer and electrically switchable functional film, as seen from the inside of the laminated pane. This ensures high contrast and brightness and thus good recognizability of the virtual image reflected by the reflective layer, especially when the electrically switchable functional film is in the first switching state (opaque).
[0024] The reflective layer serves to reflect light. The reflective layer is preferably opaque or partially translucent, which, within the meaning of the invention, means that it has an average transmission (according to ISO 9050:2003) in the visible spectral range of preferably at most 80%, particularly preferably at most 50%, and in particular less than 10%. The reflective layer preferably reflects at least 10%, particularly preferably at least 50%, and very particularly preferably at least 80%, and in particular at least 90% of the light incident on the reflective layer. The reflective layer preferably reflects p-polarized and s-polarized light in equal proportions, but it can also reflect p-polarized light and s-polarized light to different degrees.In one embodiment, the light reflected by the reflective layer is predominantly p-polarized light, so that the virtual image is clearly visible even when wearing s-polarized sunglasses. Methods for measuring light reflection are known to those skilled in the art. A light source (standard light source A) and a detector are arranged on the same side of the reflective layer, with the detector capturing the reflected light. The light from the light source strikes the reflective surface, for example, at an angle of 80° to the normal.
[0025] The light reflected by the reflective layer is preferably visible light, i.e. light in a wavelength range of approximately 380 nm to 780 nm. The reflective layer preferably has a high and uniform reflectance (over different angles of incidence) with respect to p-polarized and / or s-polarized radiation, so that a high-intensity and color-neutral image representation is ensured.
[0026] The polarization direction 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 defined by the incidence vector and the surface normal of the composite pane at the geometric center of the irradiated area.
[0027] In other words, the polarization, particularly the proportion of p- and s-polarized radiation, is determined at a point in the area irradiated by the image display device, preferably at the geometric center of the irradiated area. Since composite panes can be curved (for example, when designed as a windshield), which affects the plane of incidence of the image display device's radiation, slightly different polarization components may occur in the remaining areas, which is unavoidable for physical reasons.
[0028] In a preferred embodiment of the invention, the reflective layer is a metallic layer, i.e. a layer containing or consisting of metal.
[0029] The reflective layer preferably contains at least one metal selected from a group consisting of aluminum, magnesium, tin, indium, titanium, tantalum, niobium, nickel, copper, chromium, cobalt, iron, manganese, zirconium, cerium, scandium, yttrium, silver, gold, platinum, palladium, ruthenium, or mixtures thereof. Aluminum, titanium, and / or nickel are preferred because they can exhibit high reflection for p-polarized or s-polarized light. Aluminum is particularly preferred.
[0030] The reflective layer preferably has a thickness of 10 nm (nanometers) to 100 pm (micrometers), particularly preferably from 50 nm to 50 pm, in particular from 100 nm to 5 pm.
[0031] In a particular embodiment of the invention, the reflective layer is a coating comprising a thin-film stack, i.e., a sequence of thin individual layers. This thin-film stack contains one or more electrically conductive layers based on nickel, titanium, and / or aluminum. The electrically conductive layer based on nickel, titanium, and / or aluminum imparts basic reflective properties to the reflective layer, as well as an IR-reflecting effect and electrical conductivity. The electrically conductive layer is based on nickel, titanium, and / or aluminum. The conductive layer preferably contains at least 90 wt.% nickel, titanium, and / or aluminum, more preferably at least 99 wt.% aluminum, and most preferably at least 99.9 wt.% nickel, titanium, and / or aluminum.The layer based on aluminum, nickel and / or titanium can contain dopants, for example palladium, gold, copper or silver. Materials based on aluminum, nickel and / or titanium are particularly suitable for reflecting light, particularly preferably p-polarized light. The use of nickel, titanium and / or aluminum in metallic coatings has proven particularly advantageous for reflecting light. Aluminum, nickel and / or titanium are significantly cheaper than many other metals such as gold or silver. The individual layers of the thin-film stack preferably have a thickness of 10 nm to 1 pm. The thin-film stack preferably has 2 to 20 individual layers and in particular 5 to 10 individual layers.
[0032] As described above, at least one masking layer is arranged in the composite pane according to the invention. The masking layer is preferably arranged in an edge region of the composite pane, which typically borders the edge of the pane. The great advantage of this arrangement arises when the composite pane is used in a vehicle as a windshield, since the masking layer, when arranged in an edge region, lies outside the driver's primary field of vision.
[0033] The masking layer is preferably arranged at least along the lower edge and adjacent to the lower edge. This results in a rectangular opaque strip arranged along the lower edge in a plan view of the laminated pane.
[0034] In a particular embodiment of the composite pane according to the invention, the masking layer is designed in a frame-shaped manner all the way around. In a section in which the reflective layer is arranged so as to overlap with the masking layer, the frame-shaped masking layer is provided, for example, with a widening, i.e. it has a greater width (dimension perpendicular to the extension) than in other sections. In this way, the masking layer can be suitably adapted to the dimensions of the reflective layer (in combination with the electrically switchable functional film). In one embodiment, the masking layer is thus designed in a frame-shaped manner all the way around and, in particular, has a greater width in a section that overlaps with the reflective layer than in sections different therefrom.
[0035] For example, the reflective layer is essentially rectangular in shape, extending in an area near the bottom edge between the two side edges. For example, the edges of the reflective layer do not extend to the side edges and the bottom edge, but are spaced apart from them by, say, 2 cm to 5 cm.
[0036] The masking layer, in the sense of the invention, is a layer that prevents visibility through the composite pane. In this case, less than 5%, preferably less than 1.5%, in particular no more than 0.1%, of the light of the visible spectrum is transmitted through the masking layer. The masking layer is therefore an opaque masking layer, preferably a black masking layer. Methods for measuring light transmission are known to those skilled in the art. A light source (standard light source A) is arranged on one side of the masking layer, and a detector is arranged on the other side of the masking layer, with the transmitted light being detected by the detector.
[0037] The masking layer is preferably a coating consisting of one or more layers. Alternatively, the masking layer can also be a colored region of the thermoplastic intermediate layer. According to a preferred embodiment of the composite pane, the masking layer consists of a single layer. This has the advantage of particularly simple and cost-effective production of the composite pane, since only a single layer needs to be formed for the masking layer. The masking layer is, in particular, an opaque cover print made of a dark, preferably black, enamel.
[0038] Advantageously, the masking layer is formed as an opaque masking print arranged on the interior-side surface (side II) of the outer pane, in particular made of a dark, preferably black, enamel. Alternatively or additionally, the masking layer is formed as an opaque masking print arranged on the exterior-side surface (side III) of the inner pane, in particular made of a dark, preferably black, enamel. In particular, a first opaque masking print can be arranged on the interior-side surface (side II) of the outer pane and a second opaque masking print can be arranged on the exterior-side surface (side III) of the inner pane.
[0039] In an alternative embodiment, the masking layer is formed as an opaquely colored region of the thermoplastic intermediate layer. In one embodiment, the thermoplastic intermediate layer is formed in one piece and is opaquely colored in one region.
[0040] A masking layer formed as an opaque colored region of the thermoplastic intermediate layer can also be realized by using a thermoplastic intermediate layer composed of an opaque thermoplastic functional film and a transparent thermoplastic functional film. The transparent and opaque functional films consist of the same plastic or preferably contain the same plastic. The materials on which the opaque functional film and the transparent functional film can be formed are those also described for the thermoplastic intermediate layer. The opaque functional film is preferably a colored functional film, which can have various colors, in particular black.
[0041] In one embodiment of the composite pane according to the invention, a reflective layer for reflecting light is arranged on the interior-side surface of the glass pane, and a protective layer is arranged on this reflective layer. The protective layer is preferably transparent and applied flatly, in particular congruently, to the reflective layer. The protective layer is preferably a polymer based on polyacrylates, polyoximes, alkyd resins, polyurethanes, or mixtures thereof. The protective layer preferably has a thickness of 50 nm to 10 pm, and particularly preferably of 100 nm to 5 pm. The protective layer protects the reflective layer from mechanical damage such as scratches. It can also serve to increase the durability of the reflective layer.
[0042] In a preferred embodiment of the invention, the protective layer is an easy-to-clean layer and / or an anti-fingerprint layer. Within the meaning of the invention, an easy-to-clean layer means that dirt in the form of, for example, fingerprints, grease stains, and dirt particles on the protective layer can be removed from the protective layer using a cloth, preferably a microfiber cloth. Grease-dissolving or abrasive cleaning agents as well as solvents, for example, alcohol-based ones, are therefore largely avoided for cleaning the protective layer. Within the meaning of the invention, an anti-fingerprint layer means a layer in which fingerprints adhering to the protective layer are barely or not at all visually perceptible.Fingerprints are specifically the fatty components of a human finger that can remain on a surface when touching it and can have an unsightly effect.
[0043] The composite pane is preferably curved in one or more directions, as is common for automotive windows, with typical radii of curvature ranging from approximately 10 cm to approximately 40 m. However, the composite pane can also be flat, for example, if it is intended for use as a pane for buses, trains, or tractors.
[0044] The thermoplastic intermediate layer, via which the outer pane is connected to the inner pane, contains at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) or polyurethane (PU) or mixtures or copolymers or derivatives thereof, particularly preferably PVB. The thermoplastic intermediate layer is typically formed from a thermoplastic functional film (connecting film). The thickness of the thermoplastic intermediate layer is preferably from 0.2 mm to 2 mm, particularly preferably from 0.3 mm to 1 mm, for example 760 pm. The thermoplastic intermediate layer can be formed by a single film or by more than one film. The thermoplastic intermediate layer can also be a film with functional properties, for example a film with acoustically dampening properties.
[0045] The outer pane and inner pane preferably contain or consist of glass, particularly preferably flat glass, float glass, quartz glass, borosilicate glass, soda-lime glass, aluminosilicate glass, or clear plastics, preferably rigid clear plastics, in particular polyethylene, polypropylene, polycarbonate, polymethyl methacrylate, polystyrene, polyamide, polyester, polyvinyl chloride and / or mixtures thereof.
[0046] The outer pane and the inner pane can be clear and colorless, but also tinted or colored. In a preferred design, the total transmission through the windshield in the main viewing area is greater than 70% (illuminant A). The term "total transmission" refers to the procedure for testing the light transmittance of motor vehicle windows specified in ECE-R 43, Annex 3, Section 9.1. The outer pane and the inner pane can independently be untempered, partially tempered, or toughened. If at least one of the panes is to be tempered, this can be thermally or chemically toughened.
[0047] The thickness of the outer pane and the inner pane can vary widely and thus be adapted to the requirements of the individual case. The outer pane and the inner pane preferably have thicknesses of 0.5 mm to 5 mm, particularly preferably of 1 mm to 3 mm, and most preferably of 1.6 mm to 2.1 mm. For example, the outer pane has a thickness of 2.1 mm and the inner pane a thickness of 1.6 mm. However, the outer pane or, in particular, the inner pane can also be thin glass with a thickness of, for example, 0.55 mm.
[0048] The composite pane according to the invention can comprise one or more additional intermediate layers, in particular functional intermediate layers. An additional intermediate layer can, in particular, be an intermediate layer with acoustically dampening properties, an infrared-reflecting intermediate layer, an infrared-absorbing intermediate layer, a UV-absorbing intermediate layer, an at least partially colored intermediate layer, and / or an at least partially tinted intermediate layer. If several additional intermediate layers are present, these can also have different functions.
[0049] The invention also relates to a projection arrangement comprising a composite pane according to the invention and an imaging unit directed onto the reflection layer.
[0050] The invention therefore also relates to a projection arrangement which comprises: a composite pane, comprising an outer pane with an outer surface and an interior surface, a thermoplastic intermediate layer, an inner pane with an outer surface and an interior surface, at least one masking layer which is arranged between the outer pane and the inner pane, at least one electrically switchable functional film which can be switched between a first switching state with lower optical transmission and a second switching state with higher optical transmission by applying an operating voltage, wherein the electrically switchable functional film is arranged directly adjacent to the masking layer or in overlap with an opening in the masking layer when viewed perpendicularly through the composite pane,wherein the masking layer and the electrically switchable functional film are arranged in a region of the composite pane, at least one reflective layer for reflecting light on the outer surface and / or on the inner surface of the inner pane, wherein the reflective layer, when viewed perpendicularly through the composite pane, is arranged entirely in the region of the composite pane in which the masking layer and the electrically switchable functional film are arranged, and an imaging unit directed onto the reflective layer.
[0051] The reflective layer with the masking layer behind it from the perspective of a vehicle occupant, in combination with the electrically switchable functional film, ensures good visibility of the virtual image in a projection arrangement according to the invention, even in external sunlight and when using low-light imaging units. Even under these conditions, the image generated by the imaging unit appears bright and is clearly recognizable. This enables a reduction in the power of the imaging unit and thus reduced energy consumption.
[0052] From the perspective of a vehicle occupant, the reflective layer is positioned spatially in front of the combination of masking layer and electrically switchable functional film when viewed through the inner pane. The area of the composite pane where the reflective layer is located therefore appears opaque. The expression "viewing through the composite pane" means that the view through the composite pane starts from the interior-side surface of the composite pane. For the purposes of the present invention, "spatially in front" means that the reflective layer is positioned spatially further away from the outer surface of the outer pane than the masking layer and the electrically switchable functional film.
[0053] The imaging unit of the projection arrangement emits light and is arranged adjacent to the interior-side surface of the inner pane such that the imaging unit irradiates this surface, with the light being reflected by the reflective layer of the composite pane. The reflective layer preferably reflects at least 10%, more preferably at least 50%, most preferably at least 80%, and in particular at least 90% of the light incident on the reflective layer in a wavelength range from 400 nm to 700 nm and at angles of incidence from 55° to 80°. This is advantageous in order to achieve the greatest possible brightness of an image emitted by the imaging unit and reflected by the reflective layer.
[0054] The imaging unit is used to emit an image and can therefore also be referred to as a projector, display device, or image display device. A display or another device known to those skilled in the art can also be used as the imaging unit. The imaging unit is preferably a display, particularly preferably an LCD display, LED display, OLED display, or electroluminescent display, in particular an LCD display. Displays have a low installation height and are therefore easy and space-saving to integrate into the dashboard of a vehicle. Furthermore, displays are significantly more energy-efficient to operate than other imaging units. The comparatively lower brightness of displays is entirely sufficient in the inventive combination of the reflective layer with the underlying masking layer and electrically switchable functional film.The radiation from the imaging unit preferably strikes the composite pane in the region of the reflective layer at an angle of incidence of 55° to 80°, preferably 62° to 77°. The angle of incidence is the angle between the incidence vector of the radiation from the image display device and the surface normal at the geometric center of the reflective layer.
[0055] The imaging unit is advantageously designed such that either the entire area consisting of the masking layer and the electrically switchable functional film (as viewed vertically through the composite pane) or only the area of the masking layer alone is used for reflection at the reflective layer. In other words, the imaging unit can generate the image such that it is reflected by the reflective layer in an area that overlaps the combination of the masking layer and the electrically switchable functional film (as viewed vertically through the composite pane). The image is therefore also reflected by an area of the reflective layer that overlaps the electrically switchable functional film (as viewed vertically through the composite pane). In this case, the electrically switchable functional film is in the first switching state (opaque).On the other hand, the imaging unit can generate the image in such a way that it is reflected by the reflective layer in an area that only overlaps the masking layer and thus does not overlap the electrically switchable functional film (as viewed perpendicularly through the laminated pane). In this case, the electrically switchable functional film can be in the second switching state (transparent).
[0056] The above-described embodiments of the composite pane according to the invention also apply accordingly to the projection arrangement according to the invention and vice versa.
[0057] The invention also relates to a method for producing a composite pane according to the invention, comprising: a) providing an outer pane with an outer surface (I) and an interior surface (II), a thermoplastic intermediate layer, and an inner pane with an outer surface (III) and an interior surface (IV); b) steps i) to iii): i) forming at least one masking layer arranged between the outer pane and the inner pane, and ii) arranging at least one electrically switchable functional film, which can be switched between a first switching state with lower optical transmission and a second switching state with higher optical transmission by applying an operating voltage, such that, when viewed perpendicularly through the composite pane, it is arranged directly adjacent to the masking layer or overlapping an opening in the masking layer,wherein the masking layer and the electrically switchable functional film are arranged in one region of the composite pane, and iii) forming at least one reflective layer for reflecting light on the outer surface (III) and / or on the interior surface (IV) of the inner pane, wherein the reflective layer, when viewed perpendicularly through the composite pane, is formed entirely in the region of the composite pane in which the masking layer and the electrically switchable functional film are arranged, c) connecting the outer pane and the inner pane via the thermoplastic intermediate layer, wherein the thermoplastic intermediate layer is arranged between the outer pane and the inner pane.
[0058] The steps can be performed in the specified order, simultaneously, or in a different order. Step c) occurs after steps a) and b). If the composite pane is to be curved, a curved outer pane and a curved inner pane are used in step a). The composite in step c) can be produced using lamination processes familiar to those skilled in the art. When creating the reflective layer in step b), the reflective layer can be applied using generally known coating processes, such as magnetron sputtering or cold spraying.
[0059] The above-described embodiments of the composite pane according to the invention also apply accordingly to methods for producing a composite pane according to the invention.
[0060] The invention also relates to the use of a composite pane according to the invention as a vehicle pane in means of transport for traffic on land, in the air or on water, in particular in motor vehicles and in particular as a windscreen for a head-up display.
[0061] The various embodiments of the invention can be implemented individually or in any combination. In particular, the features mentioned above and those 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.
[0062] The invention is explained in more detail below using exemplary embodiments, with reference to the accompanying figures. They show, in simplified form and not to scale:
[0063] Fig. 1 is a plan view of an embodiment of the composite pane according to the invention,
[0064] Fig. 2 is a plan view of another embodiment of the composite pane according to the invention,
[0065] Fig. 3 is a cross-section through the embodiment shown in Figure 1,
[0066] Fig. 4 shows a cross section through an embodiment of the projection arrangement according to the invention, Fig. 5A shows a cross section through the embodiment shown in Figure 1 with an electrically switchable functional film in the transparent switching state,
[0067] Fig. 5B a cross-section through the embodiment shown in Figure 1 with an electrically switchable functional film in the opaque switching state,
[0068] Fig. 6A shows a cross section through the embodiment shown in Figure 2 with an electrically switchable functional film in the transparent switching state,
[0069] Fig. 6B a cross-section through the embodiment shown in Figure 2 with an electrically switchable functional film in the opaque switching state,
[0070] Fig. 7A shows a cross section through a further embodiment with an electrically switchable functional film in the transparent switching state,
[0071] Fig. 7B shows a cross section through a further embodiment with an electrically switchable functional film in the opaque switching state,
[0072] Fig. 8A is a plan view of the embodiment of the composite pane according to the invention of Figure 2 with electrically switchable functional film in the transparent switching state,
[0073] Fig. 8B is a plan view of the embodiment of the composite pane according to the invention of Figure 2 with electrically switchable functional film in the opaque switching state,
[0074] Fig. 9 shows an embodiment of the method according to the invention using a flow chart.
[0075] Figures 1 and 2 each show a plan view of an embodiment of the composite pane 100 according to the invention and Figure 3 shows the cross section through the composite pane 100 shown in Figure 1 along the section line XX'.
[0076] The composite pane 100 shown in Figures 1 and 2 has an upper edge O, a lower edge U and two side edges S. Furthermore, the composite pane 100 comprises an outer pane 1 with an outer surface I and an inner surface II, an inner pane 2 with an outer surface III and an inner surface IV, a thermoplastic intermediate layer 3, a first masking layer 4 and a second masking layer 8. The thermoplastic intermediate layer 3 is arranged between the outer pane 1 and the inner pane 2. The outer pane 1, the thermoplastic intermediate layer 3 and the inner pane 2 are arranged one above the other over their entire surface. The first masking layer 4 is arranged between the thermoplastic intermediate layer 3 and the inner pane 2 in a region of the composite pane 100 whose areal extent is smaller than the areal extent of the composite pane 100, i.e.the first masking layer 4 does not extend over the entire surface of the composite pane 100. The second masking layer 8 is arranged between the thermoplastic intermediate layer 3 and the outer pane 1 in a region of the composite pane 100 whose areal extent is smaller than the areal extent of the composite pane 100, i.e. the second masking layer 8 does not extend over the entire surface of the composite pane 100. In the embodiment shown in Figures 1 and 2, the two masking layers 4, 8 are each designed as an opaque cover print and are arranged only in an edge region of the composite pane 100 bordering the lower edge U. In the embodiment shown in Figures 1 and 2, the two masking layers 4, 8 extend between the two side edges S of the composite pane 100 and, starting from the lower edge U of the composite pane 100, have a width of 30 cm, for example.
[0077] The composite pane 100 further comprises an electrically switchable functional film 6, which can be switched between a first switching state with lower optical transmission (opaque) and a second switching state with higher optical transmission (transparent) by applying an operating voltage. In Figure 1, the electrically switchable functional film 6 is arranged, when viewed vertically through the composite pane 100, in (complete) overlap with an opening 7 in the first masking layer 4. The opening 7 in the first masking layer 4 can be made opaque by the electrically switchable functional film 6 in the first switching state. In Figure 2, the electrically switchable functional film 6 is arranged, when viewed vertically through the composite pane 100, directly adjacent to the first masking layer 4 in order to (completely) enlarge the opaque region of the composite pane 100.In Figure 2, the first masking layer 4 has no perforation. In other words, the first masking layer 4 and the electrically switchable functional film 6 are used in combination to arbitrarily change the size of the opaque region of the composite pane 100. In the first switching state of the electrically switchable functional film 6, the opaque region of the composite pane 100 results from the combination of the opaque regions of the first masking layer 4 and the electrically switchable functional film 6, based on a vertical view through the composite pane 100. In the second switching state, the opaque region of the composite pane 100 results from the first masking layer 4 alone. In Figures 1 and 2, the electrically switchable functional film 6 is in the transparent switching state.
[0078] The electrically switchable functional film 6 is a guest-host functional film, an electrochromic functional film, an SPD functional film, or a PDLC functional film. Typical values for the optical transparency (TL) and typical haze values of electrically switchable functional films are shown in the table below:
[0079] Furthermore, the composite pane 100 comprises a reflective layer 5 for reflecting light on the outer surface (III) of the inner pane 2, wherein the reflective layer 5, when viewed perpendicularly through the composite pane 100, is arranged entirely in the region of the composite pane 100 in which the first masking layer 4 and the electrically switchable functional film 6 are arranged.
[0080] Figure 3 shows a modification of the embodiment of Figure 1, in which the two masking layers 4, 8 are each formed in a frame-shaped circumferential manner, wherein the width of the region of the masking layers 4, 8 which is arranged in overlap with the reflection layer 5 (in a vertical view through the composite pane 100) is wider than the remaining part of the masking layers 4, 8. In Figures 1 and 2, the frame-shaped circumference of the masking layer 4 is not shown for the sake of simplicity.
[0081] The thermoplastic intermediate layer 3 contains, for example, PVB and has a thickness of 0.76 mm. The outer pane 1 consists, for example, of soda-lime glass and is 2.1 mm thick. The inner pane 2 consists, for example, of soda-lime glass and is 1.6 mm thick.
[0082] It is understood that the composite pane 100 may have any suitable geometric shape and / or curvature. Typically, the composite pane 100 is a curved composite pane. For example, the composite pane 100 is the windshield of a motor vehicle.
[0083] Fig. 4 shows a cross-section through an embodiment of the projection arrangement 101 according to the invention. The projection arrangement 101 shown in Figure 4 comprises a composite pane 100 and an imaging unit 9. The imaging unit 9 serves to generate p-polarized light and / or s-polarized light (image information), which is directed onto the reflective layer 5 and is reflected by the reflective layer 5 as reflected light into the vehicle interior, where it can be perceived by an observer, e.g. the driver. The reflective layer 5 is designed to reflect the light of the imaging unit 9. The light preferably strikes the reflective layer 5 at an angle of incidence of 55° to 80°, in particular of 62° to 77°. The imaging unit 9 is, for example, a display, in particular an LCD display.Preferably, the imaging unit 9 serves to generate only p-polarized light, which can be clearly seen, in particular, with polarizing sunglasses having an s-polarization filter.
[0084] The imaging unit 9 is designed such that the image is directed onto the reflection surface 5 such that either an area of the reflection layer 5 overlapping the area comprising the first masking layer 4 and the electrically switchable functional film 6 or an area of the reflection layer 5 overlapping only the first masking layer 4 is used for reflection (as viewed perpendicularly through the composite pane 100).
[0085] Figure 5A shows a cross-section through the embodiment shown in Figure 1, wherein the electrically switchable functional film 6 is in the transparent switching state (no applied operating voltage). In this case, the opaque region of the composite pane 100 is reduced to the first masking layer 4, i.e., the opening 7 is transparent. The image generated by the imaging unit 9 is generated such that it is reflected by the reflective layer 5 in a region that only overlaps the first masking layer 4 and therefore does not overlap the electrically switchable functional film 6 (as viewed perpendicularly through the composite pane). Figure 5B shows a cross-section through the embodiment shown in Figure 1, wherein the electrically switchable functional film 6 is in the opaque switching state (applied operating voltage).In this case, the opaque region of the composite pane 100 results from the first masking layer 4 in combination with the electrically switchable functional film 6, i.e., the entire aperture 7 is opaque. The image generated by the imaging unit 9 is generated such that it is reflected by the reflection layer 5 in an area that overlaps the combination of the first masking layer 4 and the electrically switchable functional film 6 (as viewed perpendicularly through the composite pane 100).
[0086] In the embodiment of Figure 1, in which the two masking layers 4, 8 each have an opening, the part of the masking layers 4, 8 located closer to the upper edge O can be used to arrange electrical connections of the electrically switchable functional film 6 in a concealed manner.
[0087] Figures 7A and 7B show further embodiments of the composite pane 100 according to the invention. The embodiment shown in cross section in Figure 7A (analogous to Figure 6A) differs from that shown in Figure 6A only in that the reflective layer 5 is not arranged on the outside surface (side III) of the inner pane 2, but rather on the inside surface (side IV) of the inner pane 2. The embodiment shown in cross section in Figure 7B (analogous to Figure 6B) differs from that shown in Figure 6B only in that the reflective layer 5 is not arranged on the outside surface (side III) of the inner pane 2, but rather on the inside surface (side IV) of the inner pane 2. In Figures 7A and 7B, the electrically switchable functional film 6 is again shown in the transparent switching state (Figure 7A) and in the opaque switching state (Figure 7B).
[0088] Figures 8A and 8B illustrate the change in the size of the opaque region of the composite pane 100 based on a top view of the embodiment of the composite pane according to the invention shown in Figure 2. In Figure 8A, the electrically switchable functional film 6 is in the transparent switching state, while in Figure 8B it is in the opaque switching state. The size of the opaque region of the composite pane 100 can be easily changed by switching the electrically switchable functional film 6. Figure 9 shows an embodiment of the method according to the invention using a flowchart.
[0089] In a step S1, an outer pane 1 having an outer surface I and an inner surface II, a thermoplastic intermediate layer 3 and an inner pane 2 having an outer surface III and an inner surface IV are provided.
[0090] In a step S2, which comprises several sub-steps, at least one masking layer 4 is formed, which is arranged between the outer pane 1 and the inner pane 2, at least one electrically switchable functional film 6, which can be switched between a first switching state with lower optical transmission and a second switching state with higher optical transmission by applying an operating voltage, is arranged, when viewed perpendicularly through the composite pane 100, directly adjacent to the masking layer 4 or in overlap with an opening 7 of the masking layer 4, wherein the masking layer 4 and the electrically switchable functional film 6 are arranged in one region of the composite pane 100, at least one reflective layer 5 for reflecting light is formed on the outer surface (III) and / or on the interior surface (IV) of the inner pane 2,wherein the reflection layer 5, when viewed perpendicularly through the composite pane 100, is formed entirely in the region of the composite pane 100 in which the masking layer 4 and the electrically switchable functional film 6 are arranged. In a step S3, the outer pane 1 and the inner pane 2 are connected via the thermoplastic intermediate layer 3, wherein the thermoplastic intermediate layer 3 is arranged between the outer pane 1 and the inner pane 2.
[0091] Steps S1, S2 and S3 can be performed in any order or simultaneously, with step S3 occurring after steps S1 and S2.
[0092] From the above, it can be seen that the invention provides an improved composite pane in which the size of the opaque region of the composite pane can be selectively changed by switching at least one electrically switchable functional film. The image from a projector can thus be reflected by a differently sized region of the reflective layer, whereby the virtual image is clearly visually perceptible with sufficient brightness and high contrast, so that good recognizability, in particular of safety-relevant information, is reliably ensured in all weather and lighting conditions. In particular, the opaque region of the composite pane can be selectively reduced to the opaque region of the masking layer if the largest possible view through the composite pane is desired. In addition, unwanted secondary images can be avoided.In industrial series production, the composite pane can be manufactured efficiently and cost-effectively, and the production of the composite pane can be easily implemented in common manufacturing processes.
[0093] List of reference symbols:
[0094] 100 composite panes
[0095] 101 Projection arrangement
[0096] 1 outer pane
[0097] 2 inner pane
[0098] 3 thermoplastic intermediate layer
[0099] 4 first masking layer
[0100] 5 Reflective layer
[0101] 6 Functional film
[0102] 7 Breakthrough
[0103] 8 second masking layer
[0104] 9 imaging unit
[0105] O Top edge of the composite pane 100
[0106] U Bottom edge of the laminated pane 100
[0107] S Side edge of the laminated pane 100
[0108] I outside surface of the outer pane 1
[0109] II Interior surface of the outer pane 1
[0110] III outer surface of the inner pane 2
[0111] IV Interior surface of the inner pane 2
Claims
Patent claims 1. A composite pane (100) comprising an outer pane (1) with an outer surface (I) and an interior surface (II), a thermoplastic intermediate layer (3), an inner pane (2) with an outer surface (III) and an interior surface (IV), at least one masking layer (4) arranged between the outer pane (1) and the inner pane (2), at least one electrically switchable functional film (6) which can be switched between a first switching state with lower optical transmission and a second switching state with higher optical transmission by applying an operating voltage, wherein the electrically switchable functional film (6) is arranged, when viewed perpendicularly through the composite pane (100), directly adjacent to the masking layer (4) or overlapping an opening (7) in the masking layer (4),wherein the masking layer (4) and the electrically switchable functional film (6) are arranged in a region of the composite pane (100), at least one reflective layer (5) for reflecting light is arranged on the outer surface (III) and / or on the inner surface (IV) of the inner pane (2), wherein the reflective layer (5) is arranged entirely in the region of the composite pane (100) in which the masking layer (4) and the electrically switchable functional film (6) are arranged when viewed vertically through the composite pane (100).
2. Composite pane (100) according to claim 1, wherein the electrically switchable functional film (6) has an optical transmission of less than 1.5% in the first switching state and an optical transmission of more than 30% in the second switching state.
3. Composite pane (100) according to claim 1 or 2, wherein the electrically switchable functional film (6) is selected from a guest-host functional film, an electrochromic functional film, an SPD functional film and a PDLC functional film.
4. Composite pane (100) according to one of claims 1 to 3, wherein the reflection layer (5) reflects visible light to at least 10%, preferably to at least 50%, particularly preferably to at least 80% and in particular to at least 90%.
5. Composite pane (100) according to one of claims 1 to 4, wherein the reflective layer (5) is a metallic layer.
6. Composite pane (100) according to claim 5, wherein the reflective layer (5) contains or consists of aluminum, titanium and / or nickel, in particular aluminum.
7. Composite pane (100) according to one of claims 1 to 6, in which the masking layer (4) is formed in a frame-like manner and has a greater width in a section which overlaps the reflection layer (5) than in sections different therefrom.
8. Composite pane (100) according to one of claims 1 to 7, wherein the masking layer (4) is formed as an opaque cover print arranged on the interior-side surface (II) of the outer pane (1) and / or on the exterior-side surface (III) of the inner pane (2).
9. Composite pane (100) according to one of claims 1 to 7, wherein the masking layer (4) is formed as an opaque colored region of the thermoplastic intermediate layer (3).
10. Composite pane (100) according to one of claims 1 to 9, wherein the composite pane (100) is a curved composite pane.
11. Projection arrangement (101) comprising a composite pane (100) according to one of claims 1 to 10, an imaging unit (9) directed onto the reflection layer (5).
12. A method for producing a composite pane (100) according to one of claims 1 to 10, comprising a) providing an outer pane (1) with an outside surface (I) and an inside surface (II), a thermoplastic intermediate layer (3) and an inner pane (2) with an outside surface (III) and an inside surface (IV); b) forming at least one masking layer (4) which is arranged between the outer pane (1) and the inner pane (2), arranging at least one electrically switchable functional film (6), which can be switched between a first switching state with lower optical transmission and a second switching state with higher optical transmission by applying an operating voltage, in a vertical view through the composite pane (100) directly adjacent to the masking layer (4) or in overlap with an opening (7) in the masking layer (4), wherein the masking layer (4) and the electrically switchable functional film (6) are arranged in one region of the composite pane (100), and forming at least one reflective layer (5) for reflecting light on the outer surface (III) and / or on the inner surface (IV) of the inner pane (2),wherein the reflection layer (5) is formed completely in the region of the composite pane (100) in which the masking layer (4) and the electrically switchable functional film (6) are arranged when viewed perpendicularly through the composite pane (100), c) connecting the outer pane (1) and the inner pane (2) via the thermoplastic intermediate layer (3), wherein the thermoplastic intermediate layer (3) is arranged between the outer pane (1) and the inner pane (2).
13. Use of the composite pane (100) according to one of claims 1 to 10 as a vehicle pane in means of transport for traffic on land, in the air or on water, in particular in motor vehicles and in particular as a windshield for a head-up display.