Composite disc with a holographic element and method for its production

Description

[0001] The invention relates to a composite disk with a holographic element, a method for manufacturing such a composite disk, and the use of such a composite disk.

[0002] Laminated glass is used in many places today, particularly in vehicle manufacturing. The term "vehicle" here includes, among other things, road vehicles, aircraft, ships, agricultural machinery, and construction equipment. Laminated glass is also used in other areas, such as building glazing and information displays, for example, in museums or as advertising displays.

[0003] In vehicles, laminated glass is also used as a head-up display (HUD) to project information. A head-up display is a system that allows the viewer to maintain their line of sight because the visual information is projected into their field of vision. A projection device projects an image onto the laminated glass pane to display information within the viewer's field of vision. In vehicles, the projection device is typically located on the dashboard, so that the projected image is reflected onto the nearest glass surface of the laminated glass pane, which is inclined towards the viewer (see, for example, European Patent EP 0 420 228 B1 or German Patent Application DE 10 2012 211 729 A1).

[0004] For head-up displays, reflective holograms laminated between the layers of a composite panel can be used. The reflective hologram can contain recorded information. The hologram can be activated by light emitted from a projector, thus displaying the recorded information to the viewer. Head-up displays comprising holographic optical elements are disclosed, for example, in publications WO 2012 / 156124 A1 and US 2019 / 0056596 A1.

[0005] In the production of laminated discs with a holographic optical element, a layer of photopolymers is typically laminated between two discs. This lamination usually requires two layers of thermoplastic polymers, such as polyvinyl butyral, with the photopolymer layer sandwiched between them. These thermoplastic polymers often contain plasticizers or other compounds that can diffuse into the photopolymer layer. This can cause the photopolymer layer to swell or shrink, negatively impacting the holographic optical element. This effect is particularly pronounced if the holographic optical element is already embedded in the photopolymer layer before lamination.This means that after lamination, the hologram is no longer visible under the same conditions (same laser and same eyebox) as intended during the creation of the holographic optical element. An additional layer may be placed between the photopolymer layer and the thermoplastic intermediate layers to protect the photopolymer layer. The adhesion between these two layers is often not very good. This can lead to delamination, i.e., the separation of the layers in the composite disc, rendering the composite disc unusable.

[0006] US 2019 / 0101865 A1 describes a process for manufacturing a laminated holographic display in which a photopolymer layer is laminated between two glass panes using polymer layers. The exposure of the photopolymer layer, which creates the holographic optical element, takes place after the lamination step, meaning the entire lamination of the composite pane must be carried out in the dark. This is technically challenging and expensive.

[0007] US 5066525 A describes a windshield with a holographic film laminated between two panes, wherein one or two PVB layers may be used to bond the panes.

[0008] JP H07315893 A describes a composite disc with two hologram films embedded between two individual discs by lamination with several intermediate layers. The construction with two hologram films is quite complex, as multiple carrier layers are required during manufacturing.

[0009] The present invention is based on the objective of providing an improved composite disk with a holographic optical element that is easy to manufacture and of providing a simple method for manufacturing the composite disk.

[0010] The object of the present invention is achieved according to the invention by a composite disk according to claim 1. A projection arrangement and a method for manufacturing the composite disk and its use are described in further independent claims. Preferred embodiments are described in the dependent claims.

[0011] The invention relates to a composite disc comprising at least a first disc, a first thermoplastic intermediate layer, a photopolymer layer with a holographic optical element, a second thermoplastic intermediate layer, and a second disc. According to the invention, the composite disc also has a separating layer arranged between the photopolymer layer and the first thermoplastic intermediate layer. This separating layer prevents plasticizers and other components from diffusing from the thermoplastic intermediate layer into the photopolymer layer with the holographic optical element and causing swelling or shrinkage of the photopolymer there. An adhesive layer is arranged between the separating layer and the photopolymer layer. This adhesive layer prevents delamination of the layers due to poor adhesion between the separating layer and the photopolymer layer.The adhesive layer is arranged directly adjacent to the photopolymer layer and the release layer; that is, there are no further layers between the photopolymer layer and the adhesive layer, nor between the adhesive layer and the release layer. The photopolymer layer is used in conjunction with a carrier layer, which in the composite disc according to the invention is arranged between the second thermoplastic intermediate layer and the photopolymer layer. This carrier layer serves both as a support film for a photopolymer layer and can simultaneously act as a diffusion barrier layer, preventing plasticizers from penetrating the photopolymer layer from the thermoplastic intermediate layer.Thus, according to the invention, a layer stack with the following sequence is obtained: (first disc) - first thermoplastic intermediate layer - separating layer - adhesive layer - photopolymer layer with holographic element - carrier layer - second thermoplastic intermediate layer - (second disc).

[0012] The stack of layers consists of only a single photopolymer layer. This simplifies the construction of the disc.

[0013] According to the invention, the composite disc comprises a first disc, a second disc, and an intermediate stack of layers consisting of the following layers in the order from the first disc to the second disc: a first thermoplastic intermediate layer, a release layer, an adhesive layer, a photopolymer layer with at least one holographic element, a support layer, and a second thermoplastic intermediate layer. The support layer contains polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC) and has a thickness of 20 µm to 100 µm. The support layer is arranged directly adjacent to the photopolymer layer. The release layer contains polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide (PA), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC) and has a thickness of 10 µm to 300 µm.The adhesive layer is arranged directly adjacent to the photopolymer layer and the release layer. Thanks to the combination of carrier layer, adhesive layer and release layer according to the invention, a stable composite disc is obtained after lamination without impairing the holographic element in the photopolymer layer, and which is easy to manufacture.

[0014] Preferably, the support layer consists essentially of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), or cellulose triacetate (TAC), particularly preferably polyethylene terephthalate (PET). These materials provide the photopolymer layer with the mechanical stability for easy further processing and simultaneously act as a barrier against the diffusion of plasticizers or other additives from the thermoplastic intermediate layer.

[0015] Preferably, the carrier layer has a thickness of 40 µm to 90 µm, more preferably 65 µm to 80 µm. These thicknesses are particularly suitable to provide an effective barrier function against plasticizers or other additives from the thermoplastic intermediate layer.

[0016] Preferably, the separating layer consists essentially of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide (PA), polyvinyl chloride (PVC), or cellulose triacetate (TAC), particularly preferably of polymethyl methacrylate (PMMA). These separating layers act as an excellent diffusion barrier for plasticizers or other additives from the first thermoplastic intermediate layer.

[0017] Preferably, the separating layer has a thickness of 40 µm to 200 µm, particularly preferably of 65 µm to 150 µm.

[0018] In an embodiment not claimed in the claims, the composite disc comprises at least a first disc, a second disc, and an intermediate stack of layers, comprising at least the following layers in the order from the first disc to the second disc: a first thermoplastic intermediate layer, a release layer, an adhesive layer, a photopolymer layer with at least one holographic element, a substrate layer, and a second thermoplastic intermediate layer. The substrate layer contains polyamide and has a thickness of 20 µm to 100 µm. The substrate layer is arranged directly adjacent to the photopolymer layer. The release layer contains polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC) and has a thickness of 10 µm to 300 µm. The adhesive layer is arranged directly adjacent to the photopolymer layer and the release layer.Thanks to the combination of carrier layer, adhesive layer and release layer, a stable composite disc is obtained after lamination without impairing the holographic element in the photopolymer layer, which is easy to manufacture.

[0019] Preferably, the support layer consists essentially of polyamide (PA). Polyamide provides the photopolymer layer with the necessary mechanical stability for easy further processing and simultaneously acts as an effective barrier against the diffusion of plasticizers or other additives from the thermoplastic intermediate layer.

[0020] Preferably, the carrier layer has a thickness of 40 µm to 90 µm, particularly preferably 65 µm to 80 µm. These thicknesses are particularly suitable to provide an effective barrier function against plasticizers or other additives from the thermoplastic intermediate layer.

[0021] Preferably, the separating layer consists essentially of polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), or cellulose triacetate (TAC), particularly preferably of polymethyl methacrylate (PMMA). These separating layers act as an excellent diffusion barrier for plasticizers or other additives from the first thermoplastic intermediate layer.

[0022] Preferably, the separating layer has a thickness of 40 µm to 200 µm, particularly preferably of 65 µm to 150 µm.

[0023] In an embodiment not claimed in the claims, the composite disc comprises at least a first disc, a second disc, and an intermediate stack of layers, comprising at least the following layers in the order from the first disc to the second disc: a first thermoplastic intermediate layer, a release layer, an adhesive layer, a photopolymer layer with at least one holographic element, a substrate layer, and a second thermoplastic intermediate layer. The substrate layer contains polycarbonate (PC) and has a thickness of 20 µm to 100 µm. The substrate layer is arranged directly adjacent to the photopolymer layer. The release layer contains polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC) and has a thickness of 10 µm to 300 µm.The adhesive layer is positioned directly adjacent to the photopolymer layer and the release layer. Thanks to the combination of substrate, adhesive layer, and release layer, a stable composite disc is obtained after lamination without impairing the holographic element in the photopolymer layer, and it is easy to manufacture.

[0024] Preferably, the support layer consists essentially of polycarbonate (PC). Polycarbonate provides the photopolymer layer with the necessary mechanical stability for easy further processing and simultaneously acts as an effective barrier against the diffusion of plasticizers or other additives from the thermoplastic intermediate layer.

[0025] Preferably, the carrier layer has a thickness of 40 µm to 90 µm, particularly preferably 65 µm to 80 µm. These thicknesses are particularly suitable to provide an effective barrier function against plasticizers or other additives from the thermoplastic intermediate layer.

[0026] Preferably, the separating layer consists essentially of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), or cellulose triacetate (TAC), particularly preferably of polymethyl methacrylate (PMMA). These separating layers act as an excellent diffusion barrier for plasticizers or other additives from the first thermoplastic intermediate layer.

[0027] Preferably, the separating layer has a thickness of 40 µm to 200 µm, particularly preferably of 65 µm to 150 µm.

[0028] The following explanations regarding the composite disc and its components refer to all previously described embodiments.

[0029] The adhesive layer positioned between the photopolymer layer and the release layer is preferably an optically clear adhesive (OCA) or a transparent adhesive. Such adhesives are characterized by high light transmission, low opacity, no double refraction, high UV resistance, and good aging resistance. This prevents uncontrolled and therefore undesirable impairments of light transmission or unsightly distortions. The adhesive layer preferably exhibits an absorption in the visible spectral range of less than 5%, particularly less than 2% or even 1%, and preferably a opacity of less than 5%, particularly less than 2% or even 1%.

[0030] The adhesive layer is preferably formed as a homogeneous layer.

[0031] The adhesive layer preferably has a thickness of 20 µm to 200 µm, particularly preferably 50 µm to 150 µm, and most preferably 60 µm to 100 µm. This effectively prevents delamination between the release layer and the photopolymer layer and ensures good optical properties. Furthermore, adhesive layers of these thicknesses are commercially available as adhesive films.

[0032] The adhesive is preferably a chemically acting, in particular a chemically curing, or UV-curing adhesive, most preferably an acrylate adhesive or a silicone-based adhesive. The adhesive layer is specifically not a thermoplastic adhesive film, i.e., not a thermoplastic film which, after heating, causes the optical filter to bond to the glass surface, such as the thermoplastic films of the thermoplastic interlayer of the laminated glass pane.

[0033] The first and second panes each have an outer surface, i.e., an outer face, and an inner surface, i.e., an inner face, and a circumferential side edge extending between them. For the purposes of the invention, the outer surface is defined as the main surface intended to face the external environment when installed. For the purposes of the invention, the inner surface is defined as the main surface intended to face the interior when installed. In the composite pane according to the invention, the inner surface of the first pane and the outer surface of the second pane face each other.

[0034] If the laminated glass is intended to separate an interior space from the outside environment in a window opening of a vehicle or building, then, for the purposes of this invention, the inner pane is the pane facing the interior (vehicle interior). The outer pane is the pane facing the outside environment. The first pane can be either the outer pane or the inner pane, and the second pane can also be either the outer pane or the inner pane. Preferably, the first pane is the outer pane and the second pane is the inner pane.

[0035] The photopolymer layer consists of a layer of photopolymer and includes a holographic element. The holographic element is recorded there by laser interference or introduced by an embossing process. Suitable photopolymers are known to those skilled in the art and are described, for example, in EP1438634B1, WO2011054797A1 and WO2018206503A1. Cross-linked polyurethanes are preferred.

[0036] The photopolymer layer preferably has a thickness between 5 µm and 70 µm, more preferably between 10 µm and 50 µm, and most preferably between 15 µm and 20 µm. These thicknesses are particularly advantageous for the optical quality of the holographic element. Furthermore, it is advantageous to reduce the thickness of the comparatively expensive photopolymer layer and to use it in combination with a more cost-effective substrate layer.

[0037] According to the invention, the photopolymer layer is directly adjacent to the substrate layer. The photopolymer layer is applied directly to the substrate layer to obtain a film with sufficient mechanical stability for further processing. This also prevents delamination effects without the need for additional adhesive layers between the photopolymer layer and the substrate layer.

[0038] According to the invention, the layer stack arranged between the first and second disks consists of the following layers: a first thermoplastic intermediate layer, a release layer, an adhesive layer, a photopolymer layer with at least one holographic element, a support layer, and a second thermoplastic intermediate layer. Such a structure advantageously contains few layers and does not exhibit undesirable delamination effects, which can occur more frequently with the addition of further layers.

[0039] The first thermoplastic intermediate layer and the second thermoplastic intermediate layer independently contain or consist of at least polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU) or copolymers or derivatives thereof, preferably polyvinyl butyral (PVB), particularly preferably polyvinyl butyral (PVB) and additives known to those skilled in the art, such as plasticizers.

[0040] The first thermoplastic intermediate layer and the second thermoplastic intermediate layer can be formed independently of each other by a single film or by more than one film.

[0041] The first thermoplastic intermediate layer and / or the second thermoplastic intermediate layer can also be functional intermediate layers independently of each other, in particular an intermediate layer with acoustic damping properties, an infrared radiation-reflecting intermediate layer, an infrared radiation-absorbing intermediate layer, a UV radiation-absorbing intermediate layer, an intermediate layer that is at least partially colored, and / or an intermediate layer that is at least partially tinted. For example, the first thermoplastic intermediate layer or the second thermoplastic intermediate layer can also be a bandpass filter film.

[0042] The thicknesses of the first thermoplastic intermediate layer and / or the second thermoplastic intermediate layer are independently between 30 µm and 1500 µm, preferably between 50 µm and 760 µm.

[0043] The first and second panes are preferably made of glass, particularly preferably soda-lime glass, as is common for window panes. However, the panes can also be made independently of each other from other types of glass, such as quartz glass, borosilicate glass, or aluminosilicate glass, or from rigid, clear plastics, such as polycarbonate or polymethyl methacrylate. The panes can be clear, tinted, or colored. If the laminated pane is used as a windshield, it should have sufficient light transmission in the central field of vision, preferably at least 70% in the main viewing area A according to ECE-R43.

[0044] The first pane, the second pane, the first thermoplastic interlayer, and / or the second interlayer may have suitable coatings known per se, for example, anti-reflective coatings, non-stick coatings, anti-scratch coatings, photocatalytic coatings, solar control coatings, or low-E coatings. For solar control coatings, spectrally neutral coatings are preferred, and / or these are preferably applied to the first thermoplastic interlayer or to the first pane, particularly to the inner surface of the first pane.

[0045] The thickness of the first and second panes can vary widely and thus be adapted to the specific requirements. The first and second panes preferably have thicknesses of 0.5 mm to 5 mm, more preferably 1 mm to 3 mm, and most preferably 1.6 mm to 2.1 mm. For example, an outer pane has a thickness of 2.1 mm and an inner pane has a thickness of 1.6 mm. However, the outer pane, or especially the inner pane, can also be made of thin glass with a thickness of, for example, 0.55 mm.

[0046] The composite panel 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 acoustic damping properties, an infrared radiation-reflecting intermediate layer, an infrared radiation-absorbing intermediate layer, a UV radiation-absorbing intermediate layer, an intermediate layer that is at least partially colored, and / or an intermediate layer that is at least partially tinted. If several additional intermediate layers are present, they can also have different functions.

[0047] The invention also includes a projection arrangement for displaying information to a viewer, comprising at least a composite disk according to the invention and a projector directed from the inside onto the holographic optical element. The composite disk according to the invention can be configured as described above in the various embodiments.

[0048] The projector emits light with wavelengths to which the holographic optical element responds.

[0049] Laser projectors are preferred because they allow for the achievement of very discrete wavelengths.

[0050] The features of the previously described embodiments of the composite disk also relate to the projection arrangement, which is thus disclosed with all three described embodiments of the composite disk.

[0051] The invention further relates to a method for manufacturing the composite disc according to the invention, wherein: a) a first disk with an outer surface and an inner surface, a first thermoplastic intermediate layer, a second thermoplastic intermediate layer, a release layer, an adhesive layer and a second disk with an outer surface and an inner surface are provided, b) a photopolymer layer with a holographic optical element is provided, wherein the photopolymer layer is applied to a substrate layer, c) a stack of layers is formed with the following sequence of layers and disks: first disk - first thermoplastic intermediate layer - release layer - adhesive layer - photopolymer layer with holographic element - substrate layer - second thermoplastic intermediate layer - second disk, d) the stack of layers is joined by lamination.

[0052] Lamination is preferably carried out under the influence of heat, vacuum and / or pressure. Known lamination processes can be used, for example, autoclave processes, vacuum bag processes, vacuum ring processes, calender processes, vacuum laminators or combinations thereof.

[0053] All composite discs according to the invention can be manufactured using this method. The descriptions of the preferred features of the composite disc are therefore also applicable to the method. Reference is hereby made to the above descriptions regarding the preferred features.

[0054] An advantage of this method is that the holographic optical element is already contained in the layer stack before lamination, so steps c) and d) can be carried out in the presence of daylight. This is a particular advantage compared to the prior art, where lamination must be carried out in the absence of light. Furthermore, thanks to the combination of the support layer and the release layer according to the invention, impairment of the holographic element in the photopolymer layer by diffusion of plasticizers into the photopolymer layer is prevented. The adhesive layer between the release layer and the photopolymer layer prevents delamination due to poor adhesion between these layers.

[0055] The invention also includes the use of the composite glass according to the invention as interior or exterior glazing in a vehicle or a building, in particular as a vehicle window 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 which serves as a projection surface.

[0056] The invention is explained in more detail with reference to drawings and exemplary embodiments. The drawings are schematic representations and not to scale. The drawings do not limit the invention in any way. They show: Fig. 1 shows a cross-section of an embodiment of the composite disk 100 according to the invention, Fig. 2 shows a cross-section through an embodiment of the projection arrangement 101 according to the invention, Fig. 3 shows a top view of an embodiment of the composite disk 100 according to the invention and Fig. 4 shows an embodiment of the method according to the invention based on a flowchart.

[0057] Fig. 1 shows a cross-section of an embodiment of the composite disk 100 according to the invention. In the Fig. 1In the illustrated embodiment, the composite disc 100 comprises a first disc as an outer disc 1 with an inner surface II and an outer surface I, a first thermoplastic intermediate layer 3, a photopolymer layer with a holographic element 4, a second thermoplastic intermediate layer 6, and a second disc as an inner disc 2 with an inner surface IV and an outer surface III. The photopolymer layer with the holographic element 4 is arranged between the first disc 1 and the second disc 2. The first thermoplastic intermediate layer 3 is arranged between the first disc 1 and the photopolymer layer 4.

[0058] The outer pane, for example, is made of soda-lime glass and is 2.1 mm thick. The inner pane 2, for example, is made of soda-lime glass and is 1.6 mm thick.

[0059] The first thermoplastic intermediate layer 3 and the second thermoplastic intermediate layer 6 consist of the components in the Fig. 1The embodiments shown are made, for example, of polyvinyl butyral (PVB) and are each 0.38 mm thick.

[0060] A separating layer 5 is arranged between the first thermoplastic intermediate layer 3 and the photopolymer layer 4. The separating layer 5 prevents plasticizers or other added compounds from diffusing from the first thermoplastic intermediate layer 3 into the photopolymer layer 4 and causing swelling of the photopolymer layer 4, which would impair the holographic element.

[0061] An adhesive layer 9 is arranged between the release layer 5 and the photopolymer layer 4. The adhesive layer 9 improves the adhesion between the photopolymer layer 4 and the release layer 5, thus preventing delamination between these layers. The adhesive layer 9 is directly adjacent to the photopolymer layer 4 and the release layer 5. No further layer is arranged between the adhesive layer 9 and the photopolymer layer 4, nor between the adhesive layer 9 and the release layer 5.

[0062] The adhesive layer 9 is preferably an optically clear adhesive (OCA). The adhesive layer preferably has a thickness of 20 µm to 200 µm, particularly preferably 50 µm to 150 µm, and most preferably 60 µm to 100 µm. This results in good optical properties. Furthermore, adhesive layers of these thicknesses are commercially available as adhesive films.

[0063] The adhesive is preferably a chemically acting, in particular a chemically curing or UV-curing adhesive, especially preferably an acrylate adhesive or a silicone-based adhesive.

[0064] The photopolymer layer 4 preferably has a thickness of 5 µm to 70 µm, more preferably of 10 µm to 50 µm, and particularly preferably of 15 µm to 20 µm, for example 15 µm. Since the photopolymer layer 4 is the most expensive component of the layer stack, it is advantageous to use the thinnest possible photopolymer layer and, to increase mechanical stability, to use the photopolymer layer in combination with a support layer 7 made of a more cost-effective material.

[0065] The photopolymer layer 4 consists of a suitable photopolymer and includes a holographic element. Suitable photopolymer films are commercially available, for example, under the name Bayfol® < HX.

[0066] A support layer 7 is arranged between the second thermoplastic intermediate layer 6 and the photopolymer layer 4. The support layer 7 serves as a base for the photopolymer layer 4 and simultaneously prevents plasticizers or other added compounds from diffusing from the second thermoplastic intermediate layer 6 into the photopolymer layer 4 and causing it to swell, which would impair the holographic element in the photopolymer layer. The support layer 7 is directly adjacent to the photopolymer layer 4; that is, there is no other layer between the support layer 7 and the photopolymer layer 4.

[0067] According to the invention, the support layer 7 is a polymeric layer and contains or consists of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC). The support layer is particularly preferably made of polyethylene terephthalate (PET). The support layer 7 has a thickness of 20 µm to 100 µm, preferably 40 µm to 90 µm, and particularly preferably 65 µm to 80 µm. These materials provide the photopolymer layer 4 with the necessary mechanical stability for processing into a composite disc. At the same time, they act as a diffusion barrier for plasticizers and other additives from the second thermoplastic intermediate layer 6. The support layer 7 and the photopolymer layer 4 are in direct contact with each other; that is, there is no further layer between the support layer and the photopolymer layer.

[0068] According to the invention, the separating layer 5 is a polymeric layer and contains or consists of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide (PA), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC). Preferably, the separating layer consists of polymethyl methacrylate (PMMA). The separating layer 5 has a thickness of 10 µm to 300 µm, preferably 40 µm to 200 µm, and particularly preferably 65 µm to 150 µm. These separating layers act as an excellent diffusion barrier for plasticizers from the first thermoplastic intermediate layer 3. In combination with the aforementioned support layers 7, a stable composite disk 100 is obtained after lamination without impairing the holographic element in the photopolymer layer 4.

[0069] Figure 1further shows an embodiment of a composite disc 100, which is not claimed in the patent claims, the layer components of which differ from those of the previously described composite disc 100 as follows.

[0070] The support layer 7 is a polymeric layer and contains or consists of polyamide (PA). The support layer 7 has a thickness of 20 µm to 100 µm, preferably 40 µm to 90 µm, and particularly preferably 65 µm to 80 µm. Polyamide provides the photopolymer layer 4 with the necessary mechanical stability for processing into a composite disc. At the same time, it acts as a diffusion barrier for plasticizers and other additives from the second thermoplastic intermediate layer 6.

[0071] The separating layer 5 is a polymeric layer and contains or consists of polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), or cellulose triacetate (TAC). Preferably, the separating layer consists of polymethyl methacrylate (PMMA). The separating layer 5 has a thickness of 10 µm to 300 µm, preferably 40 µm to 200 µm, and particularly preferably 65 µm to 150 µm. These separating layers act as an excellent diffusion barrier for plasticizers from the first thermoplastic intermediate layer 3. In combination with the aforementioned support layers 7, a stable composite disk 100 is obtained after lamination without impairing the holographic element in the photopolymer layer 4. Thanks to the adhesive layer 9, the adhesion between the separating layer 5 and the photopolymer layer 4 is excellent.

[0072] Figure 1further shows a cross-section of an embodiment of a composite disk 100, which is not claimed in the patent claims, the layer components of which differ from those of the composite disks 100 described above as follows.

[0073] The support layer 7 is a polymeric layer and contains or consists of polycarbonate (PC). The support layer 7 has a thickness of 20 µm to 100 µm, preferably 40 µm to 90 µm, and particularly preferably 65 µm to 80 µm. Polycarbonate provides the photopolymer layer 4 with the necessary mechanical stability for processing into a composite disc. At the same time, it acts as a diffusion barrier for plasticizers and other additives from the second thermoplastic intermediate layer 6.

[0074] The separating layer 5 is a polymeric layer and contains or consists of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC). Preferably, the separating layer consists of polymethyl methacrylate (PMMA). The separating layer 5 has a thickness of 10 µm to 300 µm, preferably 40 µm to 200 µm, and particularly preferably 65 µm to 150 µm. These separating layers act as an excellent diffusion barrier for plasticizers and other additives from the first thermoplastic intermediate layer 3. In combination with the aforementioned support layers 7, a stable composite disk 100 is obtained after lamination without impairing the holographic element in the photopolymer layer 4. Thanks to the adhesive layer 9, the adhesion between the separating layer 5 and the photopolymer layer 4 is excellent.

[0075] Fig. 2Figure 1 shows a cross-section through an embodiment of the projection arrangement 101 according to the invention. The projection arrangement 101 comprises a composite disk 100 according to the invention and a projector 18. The projector 18 is arranged in an interior space. The beam path for light emanating from a projector is indicated in the drawing by reference numeral 8. The light emanating from the projector 18 strikes the holographic element in the photopolymer layer 4 and activates the hologram. The light emitted by the projector 18 is reflected by the holographic optical element in the photopolymer layer 4, so that the holograms are perceived by a viewer 10 as virtual or real images on the side of the composite disk 100 facing away from him, provided his eyes are within the so-called eyebox E.

[0076] Fig. 3shows a top view of an embodiment of the composite disc 100 according to the invention. The area in which the at least one holographic element is arranged is shown in the Fig. 3 marked with the reference symbol B. Figures 1 and 2 The figures show cross-sections along section line XX' of various embodiments. Area B, for example, is the HUD area of ​​a composite glass 100 designed as a windshield according to the invention.

[0077] Fig. 4 An embodiment of the inventive method for producing the composite disk 100 according to the invention is shown in a flowchart comprising the steps: P1 Provision of a first disc 1, a first thermoplastic intermediate layer 3, a second thermoplastic intermediate layer 6, a separating layer 5, an adhesive layer 9 and a second disc 2. P2 Provision of a photopolymer layer with a holographic optical element 4, which is applied to a support layer 7. P3 Formation of a layer stack with the following sequence of layers and disks: first disk - first thermoplastic intermediate layer - separating layer - adhesive layer - photopolymer layer with holographic element - carrier layer - second thermoplastic intermediate layer - second disk. P4 Joining the stack of layers by lamination.

[0078] All to Figure 1The described embodiments can be produced according to the described method. Providing the photopolymer layer in conjunction with the carrier film contributes to the mechanical stability of the photopolymer layer and thus improves the lamination result, since the formation of the layer stack is considerably simplified thanks to the mechanically stable individual layers.

[0079] In an alternative embodiment of a method for manufacturing a composite disk 100, which is not claimed in the patent claims, steps P1 to P4 are designed as follows: P1 Provision of a first disc 1, a first thermoplastic intermediate layer 3, a second thermoplastic intermediate layer 6, a second disc 2. P2 Provision of a photopolymer layer with a holographic optical element 4, which is embedded in a film laminate between a separating layer 5 and a support layer 7. is arranged, wherein an adhesive layer 9 is arranged between the separating layer 5 and the photopolymer layer 4. P3 Formation of a layer stack with the following sequence of layers and disks: first disk - first thermoplastic intermediate layer - separating layer - adhesive layer - photopolymer layer with holographic element - carrier layer - second thermoplastic intermediate layer - second disk. P4 Joining the stack of layers by lamination.

[0080] All to Figure 1The described embodiments can be produced according to the described method. The provision of the photopolymer layer in conjunction with the substrate layer, the release layer, and the adhesive layer further contributes to the mechanical stability of the photopolymer layer. Moreover, the formation of the layer stack is further simplified thanks to the reduced number of individual layers compared to the previously described embodiment. In addition, the photopolymer layer is protected on both sides by the directly bonded release layer. Reference symbol list:

[0081] 1. First disc 2. Second disc 3. First thermoplastic interlayer 4. Photopolymer layer with holographic element, photopolymer layer with holographic optical element 5. Separating layer 6. Second thermoplastic interlayer 7. Carrier layer 8. Beam path for light emitted from a projector 9. Adhesive layer 10. Driver / Viewer 18. Projector 100. Composite disc 101. Projection arrangement I. Outer surface of the first disc 1 II. Inner surface of the first disc 1 III. Outer surface of the second disc 2 IV. Inner surface of the second disc 2 B. Area of ​​holograms E. Eyebox X-X' Intersection line

Claims

1. Composite pane (100), comprising a first pane (1), a second pane (2), a layer stack arranged therebetween, consisting of the following layers in order from the first pane (1) to the second pane (2): a first thermoplastic intermediate layer (3), a separating layer (5), an adhesive layer (9), a photopolymer layer (4) having at least one holographic element, a carrier layer (7), and a second thermoplastic intermediate layer (6), wherein - the carrier layer (7) contains polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC) and has a thickness of 20 µm to 100 µm, wherein the carrier layer (7) is arranged directly adjacent the photopolymer layer (4), - the separating layer (5) contains polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide (PA), polyvinyl chloride (PVC), and / or cellulose triacetate (TAC) and has a thickness of 10 µm to 300 µm, and - the adhesive layer (9) is arranged directly adjacent the photopolymer layer (4) and directly adjacent the separating layer (5).

2. Composite pane (100) according to claim 1, wherein the carrier layer (7) consists essentially of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polyvinyl chloride (PVC), or cellulose triacetate (TAC), preferably consists of polyethylene terephthalate (PET).

3. Composite pane (100) according to one of claims 1 or 2, wherein the carrier layer (7) has a thickness of 40 µm to 90 µm, preferably of 65 µm to 80 µm.

4. Composite pane (100) according to one of claims 1 through 3, wherein the separating layer (5) consists essentially of polyethylene terephthalate (PET), polyethylene (PE), polymethyl methacrylate (PMMA), polycarbonate (PC), polyamide (PA), polyvinyl chloride (PVC), or cellulose triacetate (TAC), preferably consists of polymethyl methacrylate (PMMA).

5. Composite pane (100) according to one of claims 1 through 4, wherein the separating layer (5) has a thickness of 40 µm to 200 µm, preferably of 65 µm to 150 µm.

6. Composite pane (100) according to one of claims 1 through 5, wherein the adhesive layer (9) is an optically clear adhesive.

7. Composite pane (100) according to one of claims 1 through 6, wherein the adhesive layer has a thickness of 20 µm to 200 µm, preferably of 50 µm to 150 µm, particularly preferably of 60 µm to 100 µm.

8. Composite pane (100) according to one of claims 1 through 7, wherein the thickness of the photopolymer layer (4) is between 5 µm and 70 µm, preferably between 10 µm and 50 µm, particularly preferably between 15 µm and 20 µm.

9. Composite pane (100) according to one of claims 1 through 8, wherein the first thermoplastic intermediate layer (3) and / or the second thermoplastic intermediate layer (6) contain polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), or copolymers thereof.

10. Composite pane (100) according to one of claims 1 through 9, wherein the first thermoplastic intermediate layer (3) and / or the second thermoplastic intermediate layer (6) consist essentially of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), or polyurethane (PU).

11. Composite pane (100) according to one of claims 1 through 10, wherein the first pane (1) and / or the second pane (2) are made of glass, preferably of soda lime glass.

12. Projection assembly (101) at least comprising a composite pane (100) according to one of claims 1 through 11 and a projector (18) that is aimed at the holographic optical element, wherein the projector (18) is preferably a laser projector.

13. Method for producing a composite pane (100) according to one of claims 1 through 11, wherein a) a first pane (1), a first thermoplastic intermediate layer (3), a second thermoplastic intermediate layer (6), a separating layer (5), an adhesive layer (9), and a second pane (2) are provided, b) a photopolymer layer (4) having a holographic element is provided, wherein the photopolymer layer (4) is applied on a carrier layer (7), c) a layer stack is formed with the following sequence of layers and panes: first pane (1) - first thermoplastic intermediate layer (3) - separating layer (5) - adhesive layer (9) - photopolymer layer (4) having a holographic element - carrier layer (7) - second thermoplastic intermediate layer (6) - second pane (2), d) the layer stack is joined by lamination.

14. Use of a composite pane (100) according to one of claims 1 through 11 as interior glazing or exterior glazing in a vehicle or a building, in particular as a vehicle pane in means of locomotion for travel on land, in the air, or on water, in particular in motor vehicles and in particular as a windshield that serves as a projection surface.