CN114585506A

CN114585506A - Composite glass pane for holographic head-up display

Info

Publication number: CN114585506A
Application number: CN202180003678.3A
Authority: CN
Inventors: A·戈梅尔; R·坎嫩吉塞尔; A·策里帕
Original assignee: Saint Gobain Glass France SAS
Current assignee: Saint Gobain Glass France SAS
Priority date: 2020-09-14
Filing date: 2021-09-03
Publication date: 2022-06-03
Also published as: EP4210943A1; WO2022053403A1

Abstract

Method of manufacturing a composite glass sheet (100) with a hologram, the method comprising at least the steps of: a) providing a first glass pane (1) and a second glass pane (2), b) -arranging a masking strip (4) on a surface (III) of the first glass pane (1) such that the masking strip (4) defines a cut (7) for a hologram element (5), -applying a photosensitive material (15) as hologram element (5) at least in the cut (7) defined by the masking strip (4), c) removing the masking strip (4) such that a surrounding edge (8) of the hologram element (5) is exposed, d) generating at least one hologram by exposing the hologram element (5), e) forming a layer stack from the first glass pane (1), a thermoplastic interlayer (3) and the second glass pane (2), wherein the hologram element (5) is arranged between the two glass panes (1, 2), f) arranging the first glass pane (1) and the second glass pane (2) via the thermoplastic interlayer (3) Are joined to form a composite glass sheet (100).

Description

Composite glass pane for holographic head-up display

The invention relates to a method for producing a composite glass pane, in particular for a holographic head-up display, to a composite glass pane for such a display, and to the use of such a composite glass pane.

Composite glass sheets are currently used in many places, particularly in vehicle manufacturing. The term vehicle here includes, inter alia, road vehicles, aircraft, ships, agricultural machines or work implements.

Composite glass sheets are also used in other fields. Including for example building glazings or information displays in for example museums or as advertising displays.

Composite glass panels are also commonly used to display information as head-up displays (HUDs). In this case, an image is projected onto the composite pane by means of a projection device in order to fade the information into the field of view to the observer. In the vehicle sector, projection devices are arranged, for example, on the dashboard in such a way that an image projected on the nearest glass face of the composite glass pane inclined toward the observer is reflected in the direction of the observer (see, for example, european patent EP 0420228B 1 or german laid-open document DE 102012211729 a 1).

For a head-up display, a hologram laminated between glass plates of a composite glass plate may be used. The hologram may contain information recorded therein. The hologram can be activated by means of light emitted by the projector and thus reproduce the information recorded in the hologram to the observer. Head-up displays comprising holographic optical elements are disclosed for example in publications WO 2012/156124 a1 and US 2019/0056596 a 1.

There are various types of holograms. These include, for example, reflection holograms or holograms based on the principle of light wave propagation in holograms, so-called waveguide bodies or waveguide holograms. Waveguide holograms are described, for example, in US 10394032B 2, US2015205138a1 or US10061069B 2.

The hologram may be produced in a photosensitive layer laminated between two glass plates of a composite glass plate. The recorded hologram may be damaged, for example, by moisture penetrating into the layer. In addition, chemicals used, for example, during installation into a vehicle or cleaning of the composite glass sheet may damage the hologram. Since the composite glass pane is fixed with an adhesive, depending on the installation situation, the constituents of the adhesive can diffuse into the intermediate layer via the edges of the glass pane and damage the hologram located there.

DE 68912246T2 discloses a method for producing laminated glass panes, in which a hologram is introduced between two glass panes by means of a carrier, wherein the carrier must be removed before the final lamination. This is a relatively complex method which can only be automated with difficulty.

JP 409113840 a describes a glass plate with hologram elements which are cut back along the edges and embedded in a thermoplastic intermediate layer. Here, a prefabricated photosensitive film is used which has to be fixed in/on a glass plate.

In US 5341230 a, a glass pane with a three-piece hologram is described, wherein a prefabricated layer is likewise used as the hologram film.

It is therefore an object of the present invention to provide an improved method for producing a composite glass pane with a hologram and to develop an improved composite glass pane which contains an optically defect-free hologram with a high resistance to ageing.

The object of the invention is achieved by a method according to independent claim 1. Preferred embodiments follow from the dependent claims. The composite glass pane according to the invention and its use result from the other independent claims.

The present invention relates to a method of making a composite glass sheet having a hologram. Here, a first glass plate and a second glass plate are provided in step (a). If necessary, these glass plates are washed and dried and are therefore ready for further processing.

In step (b), a masking strip is disposed on a surface of the first glass plate such that the masking strip defines a cut-out for the hologram element. In this case, the masking strip completely surrounds the area provided for the hologram element and therefore the size of the hologram element is predetermined. Subsequently, a photosensitive layer is applied as a hologram element at least in the cut-outs defined by the masking strip. The photosensitive layer can be applied over the entire surface of the first glass plate and thus also on the masking strip, if this is simpler in terms of process technology. Alternatively, the photosensitive layer can also be applied only in the cutouts for the hologram elements. The term surface here refers to one of the surfaces of the first glass plate and not to both surfaces of the first glass plate. This therefore means the surface on the side of the first glass plate to be coated.

In step (c), the masking strip is removed from the surface of the first glass plate so that the surrounding edges of the hologram element made of photosensitive material are exposed. Thus, a frame region is formed around the hologram element, in which frame region no photosensitive material is arranged. Thus, the hologram elements do not reach the edge of the glass sheet and are protected in the finished composite glass sheet from moisture, chemicals, or cleaning agents that the edge of the glass sheet may come into contact with.

In step (d), at least one hologram is produced in the hologram element by exposing the photosensitive layer. Step (d) is preferably performed before the lamination of step (f) so that the lamination can be performed without protective measures being performed on the unexposed photosensitive material. In particular, it is preferred to carry out step (d) directly before or directly after the removal of the masking strip in step (c). It is also possible, depending on the photosensitive material, that step (d) is carried out after lamination.

In step (e), the first glass sheet, the thermoplastic interlayer, and the second glass sheet are arranged to create a stack of layers such that the hologram element is disposed between the first glass sheet and the second glass sheet. The thermoplastic interlayer serves to join the first glass pane and the second glass pane and thus extends planarly over the entire surface of the first glass pane or the second glass pane. The thermoplastic intermediate layer thus has a larger area than the hologram element. If no additional barrier film surrounding the hologram element is arranged, the circumferential edge of the hologram element is sealed by the thermoplastic intermediate layer and is therefore protected from external influences.

In step (f), the first glass sheet and the second glass sheet are laminated via a thermoplastic interlayer into a composite glass sheet. This is usually achieved in a lamination process under the influence of pressure and temperature.

Other steps may be integrated into the method. The order of the steps may be changed.

The method thus provides the possibility of easily manufacturing a composite glass sheet with a hologram that is protected against the penetration of moisture, chemicals or cleaning substances. Furthermore, the method produces a clean surrounding edge of the hologram element. It is therefore also possible to use a method for applying a photosensitive layer which only makes it difficult to produce clean edges. This simplifies the step of applying the photosensitive material. Since the material is applied directly to the surface of the first glass plate, optical distortions due to a film or layer arranged between the hologram and the first glass plate are avoided. Since the photosensitive material is not arranged at least in the regions where the masking strips are arranged, the edges are filled with the material of the further layer or of the thermoplastic intermediate layer and thus seal the edges of the hologram element.

A hologram refers to a reflection hologram or waveguide hologram located within a hologram element. The hologram element refers to a holographic medium in which a hologram is contained. The hologram element is obtained by applying a photosensitive material comprising a matrix and a photosensitive substance. Holograms can be recorded in such photosensitive materials by exposure to a suitable light source. In the finished composite glass pane, the material of the hologram element is no longer photosensitive, since the photosensitive material is changed during the process in such a way that the recording of the reflection hologram can no longer be continued. The term hologram element refers not only to the unexposed hologram element made of photosensitive material, but also to the final hologram element with the recorded hologram. According to the invention, the hologram element comprises at least one hologram, however preferably a plurality of individual holograms.

The first and second glass sheets have outer (i.e., exterior) and inner (i.e., interior) side surfaces, respectively, and a peripheral side edge extending therebetween. In the sense of the present invention, an outer surface denotes a main surface which is provided for facing the outside environment in the mounted position. An inner surface within the meaning of the present invention means a main surface which is provided for facing the interior space in the mounted position. In the composite glass sheet according to the present invention, the outer surface of the first glass sheet and the inner surface of the second glass sheet face each other.

In the sense of the present invention, an inner glass pane denotes a glass pane facing an interior space (vehicle interior space) if the composite glass pane is provided for separating the interior space from the outside environment in a window opening of a vehicle or a building. The outer glass sheet represents a glass sheet facing the outside environment. The first glass sheet may be an outer glass sheet or an inner glass sheet and the second glass sheet may be an outer glass sheet or an inner glass sheet.

Preferably, the first glass sheet is an inner glass sheet and the second glass sheet is an outer glass sheet. Because the hologram element is applied to the first glass pane, the perception of the hologram by the vehicle occupant is not disturbed by the thermoplastic interlayer located therebetween.

The masking strip is arranged as a continuous border of the cut-out, wherein the masking strip may be constituted by a continuous frame or a combined frame.

The masking strip is preferably applied in liquid form to the inner surface of the first glass sheet, which can be peeled off again after the curing process. This also simplifies the continuous application in the case of curved geometries of the hologram elements.

Alternatively, the masking strip is preferably assembled from solid film pieces (strips) into a continuous border of the cut. This allows a flexible adaptation and is advantageous in particular in the case of low numbers of pieces and simple geometric shapes, preferably rectangular. Adhesive tapes of self-adhesive glue are preferably used, which are peeled off after the application of the photosensitive material. Adhesive tapes which can be peeled off again without residue are preferably used here. The adhesive tape is a plastic film or paper layer coated on one side with an adhesive material. When using masking strips applied to the glass sheet in solid or film form, it is alternatively preferred to apply a cut-fit edge. This is of interest in particular for larger pieces, for which it is desirable to produce the frame in a precisely adapted manner beforehand.

The masking strip defines a cut-out on the first glass plate for the hologram element. This means that the masking strip surrounds the area for the hologram element. The cut therefore represents the surface of the first glass plate provided for the hologram element. After the application of the photosensitive material, the hologram element completely fills the cut. The masking strip has the function of a delimiting strip in that it delimits the area for the hologram element. Furthermore, it covers or masks the area where it is arranged and prevents the photosensitive material from being applied there as well. In this connection, it additionally assumes the function of a cover strip.

Preferably, before removing the masking strip in step (c), the profile of the cut is passed along the masking strip on the side facing the hologram element with a cutting tool, such as a knife or laser, so as to produce a clean edge of the hologram element.

In a preferred embodiment, the surface of the first glass plate is pretreated at least in the cut-outs for the hologram elements to improve the adhesion of the photosensitive material. This can be a particularly thorough cleaning, or a pretreatment by adhesion promoters or primers, or an activation by means of plasma. The pre-treatment is performed before the application of the photosensitive material.

In a preferred embodiment, the photosensitive material is applied in a curtain coating process or a spray coating process or a blade coating process. These methods allow for the uniform application of photosensitive material at a constant thickness even over curved geometries. Particularly preferred are curtain coating and spray coating methods, since these methods can be automated well. In the curtain coating process, the first glass plate is passed under a curtain of a constant stream of the photosensitive material, wherein the thickness of the film layer depends on the speed at which the glass plate is passed under the curtain and the flow speed of the photosensitive material. The method provides a particularly uniform layer. In the spray method, a solution of a photosensitive material is sprayed or jetted onto a first glass plate. This is very well usable in industry and can easily be adapted to different sizes of hologram elements.

The photosensitive material preferably comprises a photopolymer, silver halide or dichromated gelatin. Photopolymers are advantageous because they can be cured by exposure to light, which is particularly simple in terms of process technology. Suitable photopolymers are known to the person skilled in the art, for example from EP1438634B 1.

Silver halide or dichromate is commonly used in gelatin matrices, which are first typically dried and then hologram recordable by exposure to light. The use of silver halides and dichromates as photosensitive materials is known, for example, from DE3909289a1 and DE69020975T 2.

In a preferred embodiment, the hologram is produced in step (d) by exposure to a laser. This results in particularly good holograms and can be automated well.

In a preferred embodiment of the method, in an additional step (g), a barrier film in the form of a surrounding frame is arranged directly adjacent to the surrounding edge of the hologram element. The surrounding frame completely surrounds the hologram element without interruption. The blocking film preferably has a thickness substantially equal to the thickness of the hologram element. Air inclusions in the region of the circumferential edge of the hologram element can thereby be avoided during lamination with the thermoplastic intermediate layer. Furthermore, in the subsequent composite glass pane, local differences in thickness between the region with the hologram elements and the surrounding region can be at least partially compensated by the barrier film. According to the invention, the barrier film does not overlap the hologram element but is only mounted in its immediate vicinity adjacent to the surrounding edge of the hologram element, whereby thickness differences can be compensated. The barrier film has a cut-out having a size equal to the size of the cut-out predetermined by the masking strip. Step (g) is performed after removing the masking strip in step (c), whereby the blocking film may be arranged there in the form of a frame in the same plane as the hologram element. Thus, the hologram element and the barrier film are located in the same plane of the stack of layers and are in contact along their edges, wherein their contact faces are substantially orthogonal to the glass pane faces of the composite glass pane.

Preferably, the barrier film is combined from separate sections of barrier film into a surrounding frame. This single-piece solution can be adapted relatively flexibly to different dimensions of the hologram element.

Alternatively, the barrier film is preferably used as a continuous frame-shaped film, which has no interruption in the surrounding frame. In this sense, continuous means that the respective barrier film surrounds the hologram element without interruption, i.e. without interruption. The frame is produced by a cut-out in the area of the hologram element. By means of continuous shaping without gaps, particularly good sealing can be achieved. In contrast, quality problems can arise when using individual sections of the barrier film, each of which is placed along an edge of the hologram element. For example, air inclusions may occur in the overlapping regions of the individual strip-shaped sections of the barrier film. Thus, a planar continuous frame-shaped barrier film embodiment along the circumferential edge of the hologram element is advantageous in terms of product quality.

In a particularly preferred embodiment of the method according to the invention, the barrier film is first combined with a thermoplastic intermediate layer into a pre-composite and then the pre-composite is inserted into the stack of layers in step (e) of the method. Thus, the step (g) of arranging the barrier film is performed directly when forming the stack of layers. This allows for a simple handling by using a pre-composite made of a thermoplastic intermediate layer and a barrier film. By using these films as pre-composites, the barrier films retain their inherent stability. In particular in large-area hologram elements, the barrier film adapted to the hologram element in terms of its size is an unstable frame, which however has to be applied in a precisely adapted manner in order to prevent slippage in the layer stack. This stability problem is avoided by using a pre-complex. In addition, electrostatic effects occur when a single barrier film is used, which further makes handling difficult. By using the pre-composite, the barrier film can be made into any shape. In this way, a rounded or rounded edge configuration of the hologram element can also be achieved.

Particularly advantageously, a continuous frame-shaped barrier film is combined with the use of a pre-composite made of a barrier film and a thermoplastic composite film. The frame-shaped formation is advantageous in terms of the shape stability of the barrier film in the pre-composite. Thereby simplifying the insertion of the frame-shaped barrier film and thus avoiding the occurrence of insertion defects, thereby improving the product quality.

The barrier film may be made of a single film layer or as a two, three or more layer film stack formed from a single film layer. This may be advantageous when the thickness of the individual film layers is too small compared to the thickness of the hologram element.

In another preferred embodiment, the surrounding frame is composed of an inner frame and an outer frame. Here, the inner frame is arranged directly adjacent to the surrounding edge of the hologram element, and the outer frame is arranged directly adjacent to the inner frame. Here, the terms inner and outer refer to hologram elements which are arranged in the center of a plane and around which a frame made of a barrier film is adjacently arranged. The inner frame and the outer frame preferably have different compositions, so that the inner frame is for example a good diffusion barrier for substances from the outer frame and/or the thermoplastic intermediate layer. The outer frame has, for example, particularly good adhesion properties to the first glass plate, which improves the stability of the glass plates and facilitates lamination.

In a preferred embodiment, both the inner frame and the outer frame are manufactured in the form of polymer films. They may be introduced into the layer stack simultaneously or successively in the process. This can be carried out particularly easily in terms of process technology.

In a preferred embodiment, in step (f), a frame-shaped barrier film is first placed on the first glass plate having the hologram element so that the hologram element is located in the cut-out of the barrier film. Next, possible other layers are placed on the hologram element and the barrier film and then the thermoplastic interlayer and the second glass sheet thereon are placed. This stack of layers is then joined by lamination. Alternatively, preferably, on the first glass plate with the hologram element, a barrier film in the form of a pre-composite made of a barrier film and a thermoplastic interlayer is placed onto the hologram element such that the barrier film surrounds the circumferential edge of the hologram element. Then, a second glass plate is finally placed and the stack of layers is joined in a lamination process.

Between the individual layers of the layer stack and the film, there may be a layer improving adhesion, in particular a tackifier. In particular, the barrier film is preferably fixed to the first glazing panel by means of a tackifier to prevent slipping during the method.

If the barrier film is applied as a pre-composite with the thermoplastic intermediate layer, it is preferably free of tackifiers, adhesion-improving coatings and/or adhesives. By using a pre-complex, the production process is less prone to errors, which enables a high degree of automation. Before combining the individual layers of the composite glass sheet together in step (e), a pre-composite made of a thermoplastic interlayer and a barrier film is produced. Preferably, the barrier film is joined to the thermoplastic intermediate layer by heating to form a pre-composite. Preferably, the barrier film and the thermoplastic intermediate layer, which are to be shaped to produce the pre-composite, are heated and pressed against one another. By applying this pressure in the heated state, a stable pre-composite is produced which does not detach even when the film cools. The steps of heating and pressing the films together may be performed sequentially, for example by passing the barrier film and the thermoplastic intermediate layer jointly through a heating zone and subsequently pressed against each other by a pair of rollers. In a particularly preferred embodiment, a heated pair of rollers is used which laminates the barrier film and the thermoplastic interlayer together and in one step joins the pre-composite. The use of a pair of rollers to join the membranes is particularly advantageous because air inclusions between the membrane modules are reliably removed. The pre-composite produced from the barrier film and the thermoplastic intermediate layer can be wound on a roll and thus optionally produced and stored beforehand.

Preferably, a pre-composite is first established from a thermoplastic intermediate layer and a barrier film arranged substantially congruent. The barrier film of the pre-composite is then removed in at least one cut. In which cut-out the hologram element is positioned when the stack of layers is put together in step (e). By implementing a cut in the barrier film, an inner edge of the barrier film is formed along the cut. The cut-out is dimensioned in such a way that the blocking film surrounds the hologram element in the form of a frame. The inner edge of the barrier film and the surrounding edge of the hologram element are in direct contact here. The barrier film is a continuous uninterrupted frame. This is advantageous in terms of a reliable sealing of the hologram element. In the case of the use of a pre-composite, the frame-shaped barrier film can be arranged particularly simply. The blocking film is therefore only present in the edge region of the hologram element, where the open edge of the hologram element needs to be sealed. Here, the hologram element and the barrier film do not show any overlap.

The printing that may be present, for example an opaque cover printing (black printing in the edge region of the glass plate), is preferably applied in a screen printing process.

The lamination is preferably performed under the influence of heat, vacuum and/or pressure. Lamination processes known per se, such as autoclave processes, vacuum bag processes, vacuum ring processes, calendering processes, vacuum laminators or combinations thereof, can be used.

The invention also relates to a composite glass sheet having a hologram. The statements made in the description of the method according to the invention with respect to the composite glass sheet obtained by the method also apply, of course, to the glass sheet itself and vice versa.

The composite glass sheet according to the invention comprises a hologram. The composite glass sheet according to the invention can be manufactured with the method according to the invention and is preferably manufactured in the method according to the invention. The composite glass sheet includes at least one stacking sequence made of a first glass sheet, a thermoplastic interlayer, and a second glass sheet. The hologram element is disposed between the first glass sheet and the thermoplastic interlayer. In this case, a hologram element with a circumferential edge is arranged directly on the surface of the first glass plate. The hologram element is here in direct contact with the surface of the glass plate and is not fixed to the first glass plate by means of a carrier film or a separate adhesive layer. The thermoplastic intermediate layer has protrusions beyond the hologram element on all sides. This means that the hologram element is smaller in area than the thermoplastic intermediate layer and is exceeded on all sides by the intermediate layer. The thermoplastic interlayer is used to glue the first and second glass sheets and is therefore identical in area to the first and second glass sheets. The hologram element does not reach the edge of the glass sheet, while the thermoplastic interlayer reaches all the way to the edge of the glass sheet. The hologram element is therefore sealed in the composite glass pane at its peripheral edge by the thermoplastic intermediate layer or another layer arranged there and is therefore protected from external influences, such as moisture and cleaning agents.

Preferably, a barrier film having a cut-out is arranged between the thermoplastic interlayer and the first glass sheet. A hologram element is disposed within and completely fills the cutout. The barrier film has a shape of a surrounding frame and is in direct contact with a surrounding edge of the hologram element. Thus, the hologram element and the barrier film are located in the same plane of the stack of layers and are in contact along their edges, wherein their contact faces are substantially orthogonal to the glass pane faces of the composite glass pane. In the composite glass pane according to the invention, the blocking film in the form of a surrounding frame compensates for local differences in thickness between the region with the hologram element and the surrounding region. According to the invention, the barrier film does not overlap the hologram element but is only mounted in its immediate vicinity adjacent to the surrounding edge of the hologram element, whereby thickness differences can be compensated. Accordingly, the composite glass sheet having the hologram element has not only improved aging resistance but also improved durability by minimizing stress and glass breakage.

In a preferred embodiment, the hologram element comprises a photopolymer, a silver halide or a dichromated gelatin. This is a material particularly suitable for recording age-resistant holograms.

In a preferred embodiment, a cover film is arranged between the hologram element and the thermoplastic intermediate layer. The cover film preferably serves as a diffusion barrier for plasticizers or other substances which can diffuse from the thermoplastic intermediate layer into the hologram element and impair the optical quality of the hologram there.

Particularly preferably, an adhesive layer is arranged between the cover film and the hologram element. The adhesive layer improves the adhesion between the hologram element and the cover film. Thus, delamination between these layers is prevented.

The cover film preferably comprises or consists essentially of polyethylene terephthalate (PET), Polyethylene (PE), polymethyl methacrylate (PMMA), Polycarbonate (PC), Polyamide (PA), polyvinyl chloride (PVC) and/or cellulose Triacetate (TAC). These cover films act as excellent diffusion barriers for the plasticizer from the thermoplastic interlayer. The cover film preferably has a thickness of from 10 μm to 300 μm, particularly preferably from 40 μm to 200 μm, very particularly preferably from 65 μm to 150 μm.

The adhesive layer is preferably a so-called optically clear adhesive (OCA, optically clear adhesive) or a clear adhesive. This adhesive is characterized by high light transmittance, low haze, no double light refraction, high UV resistance and good aging resistance. Uncontrolled and thus undesired impairment of the light transmission or unsightly distortion can thereby be avoided. The adhesive layer preferably has an absorption in the visible spectral range of less than 5%, in particular less than 2% or even 1%, and preferably has a haze of less than 5%, in particular less than 2% or even 1%.

The layer of adhesive is preferably designed as a uniform layer.

The layer of the adhesive preferably has a thickness of from 20 μm to 200 μm, particularly preferably from 50 μm to 150 μm, very particularly preferably from 60 μm to 100 μm. Therefore, delamination between the cover film and the hologram element is effectively prevented, and good optical performance is achieved. In addition, adhesive layers having these thicknesses are commercially available as adhesive films. Adhesives may alternatively be used as liquid adhesives.

The adhesive is preferably an adhesive of the chemical action type, in particular of the chemical curing type, or a UV curing agent, particularly preferably an acrylate adhesive or an adhesive based on silicone. The adhesive layer is in particular not an adhesive film of the thermoplastic action type, i.e. not a thermoplastic film which causes adhesion of the optical filter to the surface of the glass plate after heating, for example a thermoplastic film of a thermoplastic interlayer of a composite glass plate.

Particularly preferably, when the holographic element comprises a photopolymer as the main component, the stacking sequence comprises a cover layer and an adhesive layer. The hologram element made of photopolymer is significantly damaged by the diffusion of the plasticizer, so that the diffusion is prevented by the cover layer and the adhesion to the hologram element is improved by the adhesive layer.

The thermoplastic interlayer comprises or consists 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 the person skilled in the art, such as plasticizers. The thermoplastic intermediate layer preferably comprises at least one plasticizer.

Plasticizers are chemical compounds that make plastics softer, more flexible, more pliable, and/or more elastic. They move the thermoelastic region of the plastic to a lower temperature so that the plastic has the desired more elastic properties in the range of the use temperature. Preferred plasticizers are carboxylic acid esters, in particular the less volatile carboxylic acid esters, fats, oils, soft resins and camphor. The other plasticizers are preferably aliphatic diesters of tri-or tetraethylene glycol. It is particularly preferred to use 3G7, 3G8 or 4G7 as the plasticizer, where the first digit represents the number of ethylene glycol units and the last digit represents the number of carbon atoms in the carboxylic acid moiety of the compound. Thus, 3G8 represents triethylene glycol di (2-ethylhexanoate), i.e. formula C₄H₉CH (CH₂CH₃) CO (OCH₂CH₂)₃O₂CCH (CH₂CH₃) C₄H₉The compound of (1).

Preferably, the thermoplastic intermediate layer comprises at least 3 wt.%, preferably at least 5 wt.%, particularly preferably at least 20 wt.%, still more preferably at least 30 wt.%, in particular at least 40 wt.% of a plasticizer. The plasticizer comprises or preferably consists of triethylene glycol di (2-ethylhexanoate).

Further preferably, the thermoplastic interlayer comprises at least 60% by weight, particularly preferably at least 70% by weight, in particular at least 90% by weight and for example at least 97% by weight, of polyvinyl butyral.

The thermoplastic intermediate layer may be formed from a single film or also from more than one film.

The thermoplastic intermediate layer can also be a functional thermoplastic intermediate layer, in particular an intermediate layer having acoustic damping properties, an infrared radiation-reflecting intermediate layer, an infrared radiation-absorbing intermediate layer, a UV radiation-absorbing intermediate layer, an at least partially dyed intermediate layer and/or an at least partially pigmented intermediate layer. The thermoplastic intermediate layer can thus also be a band-pass filter membrane, for example.

The thickness of the thermoplastic intermediate layer is from 30 μm to 1500 μm, preferably from 50 μm to 780 μm, preferably from 380 μm to 760 μm.

In a preferred embodiment, the barrier film contains up to 0.5% by weight of a plasticizer and prevents diffusion of the plasticizer through the barrier film. This is particularly advantageous, since the diffusion of plasticizers and other components from the thermoplastic intermediate layer or other adjoining layers into the hologram element is prevented and the aging resistance of the hologram element is therefore significantly improved. It is preferred to use a barrier film without a plasticizer. The thermoplastic intermediate layer comprises at least 5 wt.%, preferably at least 20 wt.% of a plasticizer.

The barrier film is preferably a polymer layer and preferably comprises or consists essentially of polyvinyl butyral (PVB), polyethylene terephthalate (PET), Polyamide (PA), Polyethylene (PE), polymethyl methacrylate (PMMA), Polycarbonate (PC), polyvinyl chloride (PVC), cellulose Triacetate (TAC). These materials can be obtained without plasticizers or with a plasticizer content of up to 0.5 wt.%, and thus form a good barrier for plasticizers from the thermoplastic interlayer.

Particularly preferably, the barrier film consists essentially of polyvinyl butyral (PVB) having a plasticizer content of up to 0.5% by weight. The PVB of the barrier film adheres particularly well to the thermoplastic interlayer and adheres well to the first glass sheet.

Alternatively, it is preferred that the barrier film consists essentially of PET or PA, wherein in this case the adhesion promoter is preferably arranged on the side facing the first glass plate. PET and PA are preferably used without plasticizer and are therefore excellent diffusion barriers for plasticizers.

In a preferred embodiment, the barrier membrane is manufactured in two parts and consists of an inner frame and an outer frame. The inner frame is arranged here directly adjacent to the circumferential edge of the hologram element. The outer frame is directly connected with the inner frame such that there is no interruption in the form of a gap between the inner frame and the outer frame. The two-part manufacturing approach can reduce undesirable interactions between the components of the hologram element and the external frame. By means of the internal frame, a further barrier can thus be arranged with respect to the hologram element. Preferably, the material composition of the inner frame and the outer frame differ in the mass of the main component. Diffusion of chemical compounds from the outer frame into the hologram element is completely or almost completely prevented by selecting for the inner frame a material which differs from the material of the outer frame not only in its plasticizer content but also in its polymer main component. The thickness of the inner frame and the outer frame is preferably approximately the same. Preferably, the barrier film has a lower plasticizer content in the region of the inner frame than in the region of the outer frame.

The hologram element preferably has a thickness of 5 μm to 500 μm, preferably 10 μm to 200 μm, particularly preferably 15 μm to 150 μm. The hologram element can be formed here by a single layer or by a plurality of layers applied on top of one another.

The thickness of the barrier film and the thickness of the hologram element preferably differ from one another by up to 30%, particularly preferably up to 20%, in particular up to 15%. This is advantageous in terms of coverage of the surrounding edge of the hologram element along as wide a range of edge heights as possible. As the edge coverage of the hologram element by the barrier film increases, its resistance to aging also increases due to the improved edge sealing. However, the inventors have found that for good results the thickness of the hologram element and the barrier film need not be exactly uniform and therefore complete edge coverage is not required. Thus, in view of the advantageous use of standardized film thicknesses in the production process, it may be intentionally not necessary to completely cover the edges with a barrier film.

In a preferred embodiment, the thickness of the barrier film and the thickness of the hologram element are substantially the same. In this way, particularly good resistance to aging can be achieved. Therefore, the local height difference is completely compensated by the barrier film, and stress is not generated due to the height difference. Furthermore, air inclusions are prevented in the region of the circumferential edge of the hologram element.

The barrier film has a thickness of 40 μm to 750 μm, preferably 50 μm to 500 μm. Within these ranges, a variety of different barrier films having different thicknesses are commercially available. The actual thickness of the barrier film depends on the thickness of the hologram element.

The windshield has an upper edge and a lower edge and two side edges extending between the upper edge and the lower edge. The upper edge denotes an edge provided to point upward in the mounting position. Lower edge means an edge arranged to point downwards in the mounting position. The upper edge is also commonly referred to as the top edge and the lower edge as the engine edge.

The windscreen panels have a central field of view, which puts high demands on their optical quality. The central field of view must have a high light transmission (typically greater than 70%). The central field of view is in particular a field of view known to the person skilled in the art as B-field of view, B-field of view or B-field of view. The B field and its technical requirements are specified in european union economic commission (UN/ECE) No. 43 regulation (ECE-R43, "uniform conditions for approval of safety glazing materials and their installation in vehicles"). Here, the B-field is specified in appendix 18.

The hologram element is advantageously arranged in the windshield in the central field of view (B field of view). The hologram element may, but need not, cover the entire area and may also extend beyond that area. The position of the hologram/holograms in the hologram element is variable and determined according to the application. The hologram/holograms may be distributed over the entire surface of the hologram element or only in small sub-areas. Preferably, the hologram element extends over at least 30%, particularly preferably over at least 50%, and furthermore particularly preferably over at least 80% of the surface of the first glass plate. In this way, a visible transition between the hologram element and the section without the hologram element can be avoided in the visible region of the glass pane. It is particularly preferred to arrange the hologram element such that the circumferential edge of the hologram element is arranged in the region of the opaque cover print. This has the advantage that the opaque cover print masks the transition from the hologram element to the barrier film or surrounding layer. The cover print is usually located in the edge region of the glass pane and covers the view to the mounting or adhesive. The windshield panes usually have a circumferential outer cover print made of opaque enamel, which serves in particular to protect and visually shield the adhesive used for mounting the pane from UV radiation. The peripheral overlay print is preferably used to also mask the surrounding edges of the hologram element. Preferably, both the outer glass pane and the inner glass pane have a cover print, so that a two-sided perspective in the edge region is prevented.

The hologram element may also have a recess or a hole, for example in the region of a so-called sensor window or camera window. These areas are arranged to be equipped with sensors or cameras, the function of which may be impaired by the hologram elements in the light path.

The hologram elements (or all hologram elements) are preferably arranged over the entire width and the entire height of the composite glass pane, wherein the surrounding edge region with a width of, for example, 5 mm to 50 mm is subtracted. The hologram element is thus encapsulated within the thermoplastic interlayer and protected from contact with the surrounding atmosphere and corrosion. The width of the surrounding edge area may be constant or vary along the frame.

The first and second glass panes are preferably made of glass, particularly preferably soda lime glass, as is customary for window panes. However, these glass plates can also be made of other glass types, such as quartz glass, borosilicate glass or aluminosilicate glass, or of rigid clear plastics, such as polycarbonate or polymethyl methacrylate. These glass plates may be clear or may also be tinted or dyed. The windshield must have sufficient light transmission in the central viewing zone, preferably at least 70% in the main perspective area a according to ECE-R43. The first and second glass plates are preferably curved, i.e. they have a curvature.

The first glass plate and/or the second glass plate may have other suitable coatings known per se, for example anti-reflection coatings, anti-adhesion coatings, scratch-resistant coatings, photocatalytic coatings or sun-protective coatings or low-emissivity coatings.

The thickness of the first and second glass plates can vary widely and can therefore be adapted to the requirements in the respective case. The first and second glass plates preferably have a thickness of 0.5 mm to 5 mm, particularly preferably 1 mm to 3 mm.

The composite glass sheet may for example be a windscreen or roof glass sheet of a vehicle or other vehicle glazing, such as a dividing glass sheet in a vehicle, preferably a rail vehicle or a bus. Alternatively, the composite glass panel may be, for example, an architectural glazing in an facade of a building or a partition glass panel in the interior of a building.

The statements made in the description of the method according to the invention with respect to the composite glass sheet obtained by the method also apply, of course, to the glass sheet itself and vice versa.

The invention also comprises a projection device for displaying information to a viewer, comprising at least a composite glass sheet according to the invention and a projector directed from the inside towards the hologram element. The composite glass pane according to the invention is configured as described above.

The projector emits light having a wavelength to which the hologram of the hologram element responds. Laser projectors are preferred because very discrete wavelengths can be achieved thereby.

Features of the foregoing embodiments of the composite glass sheet also relate to the projection device.

The invention also includes the use of a composite glass sheet with a hologram according to the invention as an interior glazing or an exterior glazing in a vehicle or building.

The invention also includes the use of the composite glass sheet according to the invention as a windscreen panel for a vehicle.

The invention is further illustrated by means of the figures and examples. The figures are schematic and not to scale. The drawings are not intended to limit the invention in any way. Wherein:

figure 1 shows a cross-section of one embodiment of a composite glass sheet made by a method according to the invention,

figure 2 shows a cross-section of one embodiment of a composite glass sheet made by the method according to the invention,

figure 3 shows a cross-section of one embodiment of a composite glass sheet manufactured by the method according to the invention,

figure 4 shows a cross-section of one embodiment of a composite glass sheet with air inclusions,

figure 5 shows a top view of an embodiment of a composite glass sheet according to the invention as a windscreen sheet,

figure 6 shows a schematic view of the method according to the invention,

figure 7 shows a cross section through an embodiment of a projection device 101 according to the invention,

fig. 8 shows a schematic top view of an intermediate stage of the method.

FIG. 1 illustrates one embodiment of a composite glass sheet 100 according to the present invention. The composite glass sheet 100 comprises a first glass sheet 1, a second glass sheet 2, a thermoplastic interlayer 3 and a hologram element 5. Fig. 5 shows a top view of composite glass sheet 100. In fig. 1 a possible cross section through the composite glass sheet according to fig. 5 along cutting line B-B' is shown. The composite glass sheet 100 may be, for example, a windshield sheet. Here, the first glass pane 1 is an inner glass pane and the second glass pane 2 is an outer glass pane. The outer glass plate consists for example of soda-lime glass and is 2.1 mm thick. The inner glass plate 1 consists for example of soda lime glass and is 1.6 mm thick. In cross section, a black print 18 is shown, which is arranged on the inner side II of the outer glass pane 2 and therefore covers the line of sight to the circumferential edge 8 of the hologram element 5.

The first glass pane 1 and the second glass pane 2 are joined to one another via a thermoplastic interlayer 3. Between the thermoplastic interlayer 3 and the first glass pane 1, a hologram element 5 is arranged, which is likewise connected to the second glass pane 2 via the thermoplastic interlayer 3. The hologram element 5 is arranged on the outer surface III of the first glass plate 1. The hologram element 5 is arranged directly on the outer surface III without a separate carrier film or joining film, so that the hologram element 5 can be perceived by an observer on the side of the first glass pane without interference. The thermoplastic intermediate layer 3 extends beyond the hologram element 5 along the entire circumferential edge 8 of the hologram element. Since the thermoplastic intermediate layer 3 has projections beyond the hologram element 5 on all sides, the hologram element 5 does not reach the edge of the glass sheet. Since the thermoplastic interlayer 3 fills the region up to the edge of the glass plate, the hologram element 5 is sealed and protected from moisture or corrosive substances.

The thermoplastic interlayer 3 comprises a thermoplastic film having a thickness of 0.76 mm and comprises, for example, 78% by weight of polyvinyl butyral (PVB) and 20% by weight of triethylene glycol di (2-ethylhexanoate) as plasticizer. The hologram element 5 comprises dichromated gelatin and has a thickness of 10 μm to 45 μm, for example 20 μm. Due to the small thickness, no air inclusions appear when laminated along the circumferential edge 8 of the hologram element. In the case of thicker hologram elements, problems with air inclusions 30 are often observed, as this is schematically shown in fig. 4.

FIG. 2 shows another embodiment of a composite glass sheet 100 according to the present invention. The composite glass sheet 100 in fig. 2 differs from the composite glass sheet shown in fig. 1 in the hologram element 5 and the additional barrier film 6. The hologram element 5 has a circumferential edge 8. Along the circumferential edge 8 of the hologram element a barrier film 6 is arranged, which surrounds the circumferential edge 8. Because the surrounding edge 8 of the hologram element 5 is completely surrounded by the barrier film 6, the hologram element 5 is effectively protected from moisture or cleaning agents or other substances that come into contact with the edges of the glass sheets of the composite glass sheet. The hologram element 5 comprises silver bromide in a gelatin matrix and has a thickness of about 100 μm. Because the hologram element has a thickness greater than 50 μm, the probability of forming air inclusions 30 (see fig. 4) is relatively high. To suppress this, a barrier film 6 in the form of a surrounding frame 12 is arranged in the same plane as the hologram element 5 on the first glass plate 1. Thus, differences in thickness between the area with the hologram element 5 and the surrounding area are avoided, which results in less stress in the composite glass sheet. For example, the barrier film 6 is composed of two PVB frames 12 having a plasticizer content of at most 0.5 wt.% lying on top of each other in a plane. The barrier film 6 has a thickness of 100 μm and is composed of two film frames having a thickness of 50 μm each, which are stacked on each other. The barrier film 6 made of PVB has excellent adhesion to the first glass sheet 1 and the thermoplastic interlayer 3, also made of PVB. Therefore, the composite glass sheet has excellent stability and aging resistance.

The blocking film 6 has a cut-out 17 which is completely filled by the hologram element 5, i.e. the blocking film is in direct contact with the hologram element 5 all the way along the circumferential edge 8. The barrier film 6 does not exhibit any overlap with the surface of the hologram element 5, but rather a targeted selective edge sealing is achieved by direct contact of the side edges. In this sense, the surface of the hologram element 5 extending substantially parallel to the

glass plates

1, 2 is referred to as the surface of the hologram element, while the edges exhibit a substantially orthogonal course to the

glass plates

1, 2.

Fig. 3 shows another embodiment of a composite glass sheet 100. The structure of the composite glass pane with respect to the thermoplastic interlayer 3 and the first and second glass panes is the same as described in connection with fig. 1 and 2. The hologram element 5 in this case comprises a photopolymer in which the hologram is recorded. The hologram element 5 is surrounded by a frame-shaped barrier film 6 as described before, which is arranged in the same plane as the hologram element. The hologram element 5 and the barrier film 6 have approximately the same thickness, for example 75 μm. A cover film 11 is arranged between the hologram element 5 and the thermoplastic intermediate layer 3. The cover film 11 serves as a diffusion barrier for plasticizers or other substances which can diffuse from the thermoplastic intermediate layer 3 into the hologram element 5 and there impair the optical quality of the hologram. Here, the cover film 11 is composed, for example, substantially, i.e., at least 97% by weight of PET, and contains no plasticizer. An adhesive layer 10 made of a transparent optical adhesive (OCA) is arranged between the cover film 11 and the hologram element 5. The adhesive layer 10 improves the adhesion between the hologram element 5 and the cover film 11. Thus, delamination between these layers is prevented.

The barrier film 6 is manufactured in fig. 3 in two parts, i.e. it is composed of an inner frame 12.1 and an outer frame 12.2. The inner frame 12.1 is arranged here directly adjacent to the circumferential edge 8 of the hologram element 5. The outer frame 12.2 is directly connected with the inner frame 12.1 so that there is no gap between the frames. In this case, the inner frame 12.1 is a polyamide film without plasticizer. The internal frame inhibits the plasticizer from diffusing from the thermoplastic intermediate layer 3 located thereon into the hologram element 5 via the frame material. The outer frame 12.2 consists of PVB with a maximum of 0.5 wt% plasticizer. The outer frame 12.2 ensures optimum adhesion in the edge region, since PVB adheres particularly well to the first glass pane 1. Therefore, the material compositions of the inner frame and the outer frame differ in the quality of the main component. The diffusion of chemical compounds from the outer frame 12.2 to the hologram element 5 is completely or almost completely inhibited by the inner frame 12.1. The thickness of the inner frame and the outer frame is preferably approximately the same.

Fig. 4 shows a composite glass sheet 100 having a similar structure as in fig. 1. Unlike the embodiment of fig. 1, the hologram element has a thickness of 100 μm. Without the additional frame, air inclusions 30 occur in the region of the hologram element 5 surrounding the edge 8 during lamination. This impairs the optical properties of the composite glass sheet and reduces the stability of the glass sheet.

Fig. 5 shows a top view of a composite glass sheet 100. The composite glass sheet is manufactured as a windshield sheet. The windscreen panel comprises a trapezoidal composite glass panel 100 having a first glass panel 1 as inner glass panel and a second glass panel 2 as outer glass panel, which are joined to each other by a thermoplastic interlayer 3. The windscreen panel has an upper edge D facing the roof in the mounted position and a lower edge M facing the engine compartment in the mounted position. Fig. 1 to 3 show a cross section of a composite glass pane 100 in detail in various embodiments. The edge regions of the composite pane are covered by a circumferential black print 18 (circumferential peripheral cover print) which is applied at least on the inner side II of the outer pane. The black print 18 is formed by printing an opaque enamel on the surface II of the second glass plate 2 on the side of the interior space, which in the mounted position faces the vehicle interior space. On the inner side IV of the first glass pane 1, a black print 18 can optionally also be applied. The surrounding edge 8 of the hologram element 5 is located in the region of the black print 18, so that it is not visible when the composite pane is viewed from the outside. The spacing of the hologram element 5 from the surrounding edge of the glass plate is therefore less than the width of the black print 18.

Fig. 6 shows a schematic view of the inventive method of making a composite glass sheet 100, as shown in fig. 2. Here, a first glass plate 1 and a second glass plate 2 are provided in step (a) (not shown). In step (B) (stages a and B in the figure), masking strip 4 is arranged onto the outer surface III of the first glass plate 1 such that masking strip 4 defines a cut-out 7 for the hologram element 5. The masking strip 4 is an adhesive tape and completely surrounds the cut 7 provided for the hologram element 5 and thus predetermines the size of the hologram element 5. Fig. 8 is a schematic plan view of an intermediate stage shown in fig. 6 (a) with a rectangular glass plate as an example. There it is visible that the adhesive tape 4 reaches the edge of the glass sheet. The diagram in fig. 6 (a) corresponds to a section along the cutting line C-C'. The cut 7 is pre-treated by plasma in order to prepare for the subsequent steps to activate the surface for applying the photosensitive material (not shown).

Subsequently, a solution of dichromated gelatin is applied as a photosensitive material in the cut 7 defined by the adhesive tape 4. The photosensitive material is applied completely over the entire outer surface III of the first glass plate 1 and also over the adhesive tape, since this is simpler in terms of process technology. The photosensitive material is applied in a curtain coating process in a uniform layer thickness. The photosensitive material is then dried, which can be done at ambient conditions (25 ℃). The results of this intermediate stage are shown in stage (B).

The transition from stage (B) to stage (C) is indicated by two arrows. In this case, the tool 22 first passes the contour of the cut 7 along the adhesive tape 4. This facilitates the detachment of the adhesive tape 4 and results in a uniform circumferential edge 8 of the hologram element 5. The adhesive tape 4 is then removed from the inner surface III of the first glass plate 1 so that the surrounding edge 8 of the hologram element 5 made of photosensitive material is exposed. Thus, a frame region is formed around the hologram element 5, in which frame region no photosensitive material is arranged. Thus, the hologram element 5 does not reach the edge of the glass sheet and is protected from moisture or cleaning agents that may come into contact with the edge of the glass sheet in the finished composite glass sheet 100. Alternatively, the step of cutting and releasing the adhesive tape may be performed later after the exposure.

In the hologram element, at least one hologram is subsequently produced by exposing the photosensitive material of the hologram element. This is done by a laser and is shown by a second arrow. Exposure before lamination has the advantage that the hologram element is no longer photosensitive. After exposure, a washing operation is preferably carried out in which the soluble constituents are removed from the dichromated gelatin layer by immersing the glass plate in different washing solutions. Such post-treatments are known for photosensitive layers made of dichromated gelatin or comprising silver halides. Finally, the glass plate is dried at a slightly elevated temperature (50 ℃ to 120 ℃). Thus, an intermediate stage (C) shown in fig. 6 is obtained.

From the intermediate stage (C) there are two paths leading to the intermediate stage (D), which are shown by different arrows. The arrow on the left shows how a barrier film 6 in the form of a frame is applied to the first glass plate and the thermoplastic interlayer 3 is subsequently placed on the hologram element 5 and the barrier film 6. The arrow on the right shows how the barrier film 6 together with the thermoplastic intermediate layer 3 is placed in the form of a pre-composite onto the glass pane.

In both cases (these two arrows), a blocking film 6 in the form of a surrounding frame is arranged directly adjacent to the surrounding edge 8 of the hologram element 5. The surrounding frame completely surrounds the hologram element without interruption. The barrier film 6 has a thickness substantially equal to the thickness of the hologram element 5. Air inclusions 30 in the region of the hologram element surrounding the edge 8 can thus be avoided when laminating with the thermoplastic intermediate layer 3. The blocking film 6 has a cut 17 with a size equal to the size of the cut 7 predetermined by the adhesive tape 4. The barrier film 6 is manufactured as a continuous film, for example a prefabricated PET frame. Preferably, the surface of the PET frame 6 facing the surface III of the first glass pane 1 is coated with a thin adhesive layer so as to ensure good adhesion to the first glass pane 1 and to prevent the PET frame 6 from slipping during lamination. It is particularly advantageous to first place the barrier film 6 on the first glass pane 1 and subsequently place the thermoplastic interlayer 3.

In the variant illustrated by the right arrow, the barrier film 6 is first joined with the thermoplastic intermediate layer 3 to form a pre-composite and the pre-composite is then placed on the first glass pane 1 with the hologram element 5. By using the thermoplastic interlayer 3 and the barrier film 6 as a pre-composite, the barrier film 6 retains its inherent stability. In particular in the case of large-area hologram elements 5, the barrier film 6, which is adapted in terms of its dimensions to the hologram element 5, is an unstable frame, which however has to be applied with a precise adaptation in order to prevent slipping in the layer stack. In addition to this, an electrostatic effect occurs when a single barrier film is used, which makes the operation further difficult.

In the intermediate stage (D) in fig. 6, a layer stack is shown, onto which the second glass sheet 2 is now placed and which is laminated in a lamination process to a composite glass sheet 100.

The method thus offers the possibility of simply producing a composite glass pane with a hologram, which is protected against penetration by moisture or cleaning substances. Furthermore, the method produces a clean surrounding edge of the hologram element, which is sealed by the barrier film.

Fig. 7 shows a cross section through an embodiment of a projection device 101 according to the invention. The projection device 101 comprises a composite glass sheet 100 according to the embodiment shown in fig. 2 and a projector 19. The projector 19 is disposed in the internal space. The light path of the light emitted by the projector is provided with reference numeral 21 in the figure. The light emitted by the projector 19 impinges on the hologram element 5 and activates the hologram. The light emitted by the projector 19 is reflected by the hologram element 5 so that, when the eye of the observer 20 is located within the so-called eye movement range E, the hologram is perceived by the observer 20 as a virtual or real image of the side of the composite pane 100 facing away from him.

List of reference numerals:

1 first glass plate

2 second glass plate

3 thermoplastic interlayer

4 masking strip

5 hologram element

6 Barrier film

7 cut-outs delimited by masking strips

8 encircling edge of hologram element

10 adhesive layer

11 cover film

12 surround frame

12.1 internal frame

12.2 outer frame

15 photosensitive material

17 cut in Barrier film

18 black printed matter

19 projector

20 driver, observer of vehicle

21 light path of light emitted by the projector

22 cutting tool

I outer surface of the second glass plate 2

II inner surface of the second glass plate 2

III outer surface of the first glass pane 1

IV inner surface of the first glass pane 1

30 enclosed air

100 composite glass plate

101 projection device

BB' cutting line

S B field of view

M Engine edge

D top edge

E eye movement range.

Claims

1. Method of manufacturing a composite glass sheet (100) with a hologram, the method comprising at least the steps of:

a) providing a first glass plate (1) and a second glass plate (2),

b) -arranging a masking strip (4) on a surface (III) of the first glass plate (1) such that the masking strip (4) defines a cut (7) for the hologram element (5),

-applying a photosensitive material (15) as a hologram element (5) at least in the cut (7) defined by the masking strip (4),

c) removing the masking strip (4) so as to expose the surrounding edge (8) of the hologram element (5),

d) generating at least one hologram by exposing the hologram element (5),

e) forming a layer stack from a first glass plate (1), a thermoplastic interlayer (3) and a second glass plate (2), wherein a hologram element (5) is arranged between the two glass plates (1, 2),

f) -joining the first glass sheet (1) and the second glass sheet (2) via the thermoplastic interlayer (3) into a composite glass sheet (100) in a lamination process.

2. The method according to claim 1, wherein the first glass plate (1) is coated with an adhesion promoter or pretreated by plasma activation at least in the incisions (7) for the hologram elements (5).

3. The method of manufacturing a composite glass plate (100) with a hologram according to any of claims 1 or 2, wherein the photosensitive material (15) is applied in step (b) by curtain coating, spraying or doctor blading, preferably by curtain coating or spraying.

4. The method of manufacturing a composite glass sheet (100) with a hologram according to any of claims 1 to 3, wherein the photosensitive material (15) comprises a photopolymer, a silver halide or a dichromated gelatin.

5. Method of manufacturing a composite glass pane (100) with a hologram according to any of claims 1 to 4, comprising the following steps

g) Arranging a barrier film (6) in the form of a surrounding frame (12) directly adjacent to the surrounding edge (8) of the hologram element (5), wherein step (g) is performed after step (c).

6. Method of manufacturing a composite glass pane (100) with a hologram according to claim 5, in which

-the surrounding frame (12) is constituted by an inner frame (12.1) and an outer frame (12.2),

-the inner frame (12.1) is arranged directly adjacent to the surrounding edge (8) of the hologram element (5), and the outer frame (12.2) is arranged directly adjacent to the inner frame (12.1).

7. Method of manufacturing a composite glass pane with hologram (100) according to any of claims 5 or 6, wherein the barrier film (6) and the thermoplastic interlayer (3) are first joined into a pre-composite and then steps (e) and (g) are jointly performed.

8. Composite glass pane (100) comprising a hologram, comprising at least a stacking sequence made of a first glass pane (1), a thermoplastic interlayer (3) and a second glass pane (2), wherein

-arranging a hologram element (5) having a circumferential edge (8) at least in regions on a surface (III) of the first glass plate (1),

-the thermoplastic intermediate layer (3) has protrusions beyond the hologram element (5) on all sides,

-a hologram element (5) is arranged between the first glass plate (1) and the thermoplastic interlayer (3),

-the hologram element (5) is arranged directly on the surface (III) of the first glass plate (1).

9. The hologram containing composite glass sheet (100) according to claim 8, wherein a barrier film (6) having a cut-out (17) is arranged between the thermoplastic interlayer (3) and the first glass sheet (1), wherein the hologram element (5) is arranged in said cut-out (17), and wherein the barrier film (6) surrounds the hologram element (5) in the form of a surrounding frame (12) and is in direct contact with the surrounding edge (8).

10. The hologram containing composite glass sheet (100) according to any of claims 8 or 9, wherein a cover film (11) is arranged between the thermoplastic interlayer (3) and the hologram element (5), and an adhesive layer (10) is arranged between the cover film (11) and the hologram element (5).

11. The hologram containing composite glass sheet (100) according to any of claims 9 or 10, wherein the barrier film (6) is manufactured in two parts and consists of an inner frame (12.1) and an outer frame (12.2), wherein the inner frame (12.1) is arranged directly adjacent to the surrounding edge (8) of the hologram element (5).

12. The composite glass sheet (100) comprising a hologram according to any of claims 8 to 11, wherein the barrier film (6) contains up to 0.5 wt% of a plasticizer and the thermoplastic interlayer contains at least 5 wt%, preferably at least 20 wt% of a plasticizer.

13. Composite glass sheet (100) comprising a hologram according to any of claims 8 to 12, produced in a method according to any of claims 1 to 7.

14. Projection device (101) comprising at least a composite glass pane (100) according to the invention according to any of claims 8 to 13 and a projector (19) directed at the hologram element (5), wherein the projector (19) is preferably a laser projector.

15. Use of a composite glass pane (100) comprising a hologram according to any of claims 8 to 13 as an interior glazing or an exterior glazing in a vehicle or a building, in particular as a vehicle glazing in a land, water and air vehicle, in particular a motor vehicle, in particular as a windscreen pane serving as a projection surface.