Method for manufacturing an illuminable vehicle roof

Abstract

The present invention relates to a method for manufacturing an illuminable laminated glass roof (1) for a vehicle, comprising: - a first transparent sheet (2) made of mineral glass, with a first main face F1, a second opposing main face F2, intended to form an exterior glass, - a transparent polymeric interlayer (5-6), comprising a first thermoplastic interlayer sheet (5) and a second thermoplastic interlayer sheet (6), - a second transparent sheet (3) made of mineral glass or polymer, with a third main face F3 and an opposing fourth main face F4, with a refractive index n1 in the visible range, - an optical isolation layer (11), transparent, with a refractive index n2 in the visible range such that n2 < n1, - a light extraction layer (13), wherein the second thermoplastic interlayer sheet (6) extends between the first thermoplastic interlayer sheet (5) and the third main face F3, the light-extraction layer (13) being in contact with the second thermoplastic interlayer sheet (6) and arranged between the optical isolation layer (11) and the third main face F3, the method comprising: - an assembly step, comprising: - positioning of the first thermoplastic interlayer sheet (5) and the second thermoplastic interlayer sheet (6) on one of the first and second transparent sheets (2, 3), referred to as the transparent reference sheet, - positioning of the other one of the first and second transparent sheets (2, 3), referred to as the other transparent sheet, - laminating the sheets, characterized in that the assembly step comprises placing on the transparent reference sheet a functional laminate (23) including a laminated bilayer (15), said laminated bilayer (15) comprising: - one of the first thermoplastic interlayer sheet (5) and the second thermoplastic interlayer sheet (6), referred to as the thermoplastic reference interlayer sheet, - said optical isolation layer (11), which comprises or is supported by a transparent polymer film, referred to as the first film, with said optical isolation layer (11) being arranged between the thermoplastic reference interlayer sheet and the other one of the first thermoplastic interlayer sheet (5) and the second thermoplastic interlayer sheet (6), referred to as the other thermoplastic interlayer sheet.

Description

[0001] METHOD FOR MANUFACTURING AN ILLUMINABLE VEHICLE ROOF

[0002] The present invention belongs to the technical field of glazing manufacture and relates to a method for manufacturing an illuminable laminated glass roof for a vehicle having a functional laminate as well as the illuminable laminated glass roof obtainable by such method. It further relates to a functional laminate as well as its manufacture. The invention finds a particularly advantageous application, although by no means limiting, in the case of a road vehicle glazing.

[0003] Modern vehicles are increasingly equipped with illuminable (luminous) glass roofs, for example, to achieve certain design effects or to display information. For this purpose, light is coupled into the glass roof and guided therein by total internal reflection to reach scattering areas, where it is extracted from the glass roof by light scattering to then be perceived by an observer. Light-emitting diodes have been used for vehicle glass roofs such as panoramic laminated glass roofs illuminated by light-emitting diodes as described in document WO 2010049638. The light emitted by the diodes is introduced via the edge face into the interior glazing forming a guide by total internal reflection, with the light being extracted from the glazing by a light extraction layer on the glazing.

[0004] As is well-known to the skilled person, at the transition from an optically denser medium to an optically thinner medium, total internal reflection can only occur above a critical angle relative to the normal direction at the interface, which critical angle depends on the optical densities of the media involved. The critical angle can be determined from the ratio of the refractive indices of the media at the transition. For example, in soda-lime glass that has interfaces with air and polyvinyl butyral (PVB), as is often the case in laminated glazing, the critical angle is approximately 78° to the glass normal, so that only light with an angle of incidence greater than 78° will be totally reflected within the glass. As the critical angle is essentially determined by the interface with PVB, in order to reduce the critical angle and thus increase the amount of light which is totally reflected at the interfaces, it is known to provide a layer with a low refractive index (Rl) between glass and PVB, wherein the Rl of the low Rl layer must be lower than the Rl of PVB.

[0005] As the adhesion to glass typically is poor, the integration of a low Rl layer (e.g., deposited on a carrier layer such as a PET-film) usually requires additional adhesive layers often made of thermoplastic polymer. Such additional adhesive layers, however, may cause problems with increasing the thickness of the laminated compound too much, degassing and handling of the adhesive layers. These problems may be reduced by using adhesive layers which are relatively thin which, however, makes them very difficult to handle by robotics. Basically, thin adhesive films are prone to tearing when transported. In addition, marking folds and dents may occur when thin adhesive films are handled (e.g., sucked) on a plotter machine or the like.

[0006] Furthermore, unstacking of thin adhesive films or peeling them off a roll makes them very electrostatic, so that they may attract and catch dust, which requires to work in a very clean environment or to perform another step of discharging the films. Generally, by having a larger number and interfaces of interleaved sheets, the likelihood of trapping dust or fibers is increased.

[0007] Further, precise positioning of the various adhesive layers in the stack to be laminated may be rather difficult and dealignment is likely to occur.

[0008] Further, a layer with a low Rl layer should not extend until the glass edge as this creates edge sealing issues, lack of adhesion for the total glazing, water infiltration and oxidation.

[0009] US 2016349442 A1 discloses a luminous laminated vehicle roof incorporating, within the thermoplastic interlayer, a fluoropolymer film having a thickness of at least 600 nm and a refractive index n2. The internal glass acts as a light guide having a refractive index n1 , with n1 - n2 being at least 0.08, so that the fluoropolymer film (Rl layer) forms an optical isolation layer between the internal glass and a tinted element such as the exterior glass.

[0010] US 2018074251 A1 discloses a laminated glazing (see Fig. 2) comprising a light source for coupling light into the lower pane at an edge thereof. The light is internally reflected in the lower pane and reflected out of the glazing by microbeads.

[0011] US 2015298601 A1 discloses a light-conducting layer, e.g. made of PMMA or PC connected to a lamination layer which can be a refractive layer with a lower index of refraction than the lightconducting layer (see e.g. Fig. 2).

[0012] WO 2014167291 A1 and DE 202021100843 U1 disclose background art illustrating a glazing configured for internal reflection.

[0013] The object of the present invention is to overcome the disadvantages of the prior art as set out above by improving the manufacture of an illuminable laminated vehicle glass roof (throughput, reliability, etc.). Specifically, problems with handling, dust trapping, electrostatic charging and precise positioning of thin adhesive layers used sheet by sheet shall be avoided. Basically, it shall be possible to produce the illuminable laminated vehicle glass roof in an easy, time- and costefficient manner with high quality and low waste.

[0014] This and further objects are solved by a method for manufacturing an illuminable laminated glass roof for a vehicle according to the independent claim. Advantageous embodiments of the invention are disclosed in the dependent claims.

[0015] According to the invention, a method for manufacturing an illuminable laminated glass roof for a vehicle, in particular a road vehicle (car, truck, public transport: bus, coach, etc.) or a rail vehicle (train, metro, tramway) is disclosed. The laminated glass roof has a curved, transparent laminated glazing.

[0016] The curved, transparent laminated glazing comprises: a first (curved) transparent sheet made of mineral glass, transparent and possibly tinted, in particular gray or green, intended to form an outer pane, with a first main face F1 (intended to face the outside of the vehicle) and a second opposing main face F2, either bare or coated with a transparent functional coating, in particular with a thickness of no more than 1 pm or 200 nm, for a road vehicle and specifically a car, wherein the first transparent sheet preferably is no thicker than 4 mm, or even no thicker than 2.5 mm, even no thicker than 2.2 mm and in particular has a thickness of 1.9 mm, 1.8 mm, 1.6 mm and 1 .4 mm and even no thicker than 0.7 mm, for example, with a refractive index n3 of at least 1.5 in the visible range, a transparent polymeric (laminated) interlayer - in adhesive contact with the third main face F3 (see second transparent sheet) - bare or coated - and with the second main face F2 - bare or coated -, preferably exclusively thermoplastic, comprising a first thermoplastic interlayer sheet, clear or tinted, possibly an upper interlayer sheet, i.e. in adhesive contact with the second main face F2 or with a functional transparent coating on the main face F2, particularly with a thickness of at most 1 pm or 200 nm, single- or multi-layered, particularly if acoustic PVB, or an intermediate interlayer sheet, single- or multi-layered, and a second thermoplastic interlayer sheet also referred to as the lower thermoplastic interlayer sheet (clear or tinted, single- or multi-layered, particularly if acoustic PVB), a light extraction layer, preferably in the form of a light scattering (diffusing) coating comprising a matrix (preferably organic) and scattering particles, with refractive index n4 in the visible range, preferably n4 greater than or equal to n1 (optionally with a roof having a blur of at most 30% in the zone with scattering pattern) or with n4 - n1 of at most 0.1 or 0.05, a second (curved) transparent sheet, transparent and possibly tinted, made of mineral glass or polymer, preferably extra-clear, with a refractive index n1 in the visible, with a third main face F3 and an opposing fourth main face F4, preferably bare or coated with a functional (transparent) coating, in particular with a thickness of at most 1 pm or 200 nm, wherein the second transparent sheet is preferably made of mineral glass, with the third main face F3 facing the outside of the vehicle and the fourth main face F4 facing the passenger compartment, notably with a thickness of at least 0.7 mm (to promote light guidance), possibly less than that of the first transparent sheet, but no more than 2.2 mm - in particular with a thickness of 1.9 mm, 1.8 mm, 1 .6 mm and 1.4 mm - or even no more than 1.3 mm or no more than 1 mm.

[0017] A total thickness of the first and second transparent sheets preferably is less than 5 mm or 4 mm, or even 3.7 mm.

[0018] The lower thermoplastic interlayer sheet, i.e., the second thermoplastic interlayer sheet, extends between the first thermoplastic interlayer sheet and the third main face F3 (in adhesive contact with the third main face F3) of the second transparent sheet. The light extraction layer is in contact with the lower thermoplastic interlayer sheet.

[0019] The laminated glass roof according to the invention also comprises, between the second main face F2 of the first transparent sheet and the third main face F3 of the second transparent sheet, an optical isolation layer, with a refractive index n2 in the visible, such that n2 < n1 , in particular an optical isolation layer, which is transparent and has a thickness in the sub-millimeter range, preferably of at least 400 nm or 800 nm.

[0020] The method for manufacturing an illuminable laminated glass roof for a vehicle comprises an assembly step, comprising: positioning of the first thermoplastic interlayer sheet and the lower interlayer sheet (i.e. the second thermoplastic interlayer sheet) on one of the first and second transparent sheets, referred to as the transparent reference sheet (direct positioning, in contact with the transparent reference sheet or on one or more interlayer sheets (electroactive element, etc.), as detailed later, particularly if the transparent reference sheet is the first transparent sheet), positioning of the other one of the first and second transparent sheets, referred to as the other transparent sheet, laminating the stack of sheets. According to the invention, the assembly step comprises the positioning on the transparent reference sheet of a functional laminate, the functional laminate comprising a laminated bilayer, the laminated bilayer comprising: one of the first thermoplastic interlayer sheet and the lower interlayer sheet (i.e. the second thermoplastic interlayer sheet), referred to as the thermoplastic reference interlayer sheet, wherein the first thermoplastic interlayer sheet preferably has a thickness of at least 0.3 mm and more preferably of at most 0.9 mm or 0.5 mm, and, in particular, is based on a first polymer (in particular based on PVB with at least 20% plasticizers), and wherein the lower interlayer sheet (film or coating) preferably has a thickness of at least 25 pm, and preferably is based on a second polymer identical or similar to the first polymer (in particular PVB with at least 20% plasticizers or TPU or EVA preferably with a thickness of at least 0.3 mm or based on PVB with at most 10% or 5% plasticizers and preferably a thickness of at most 100 pm or 50 pm), the optical isolation layer (recessed or with a free edge), said optical isolation layer comprising or being supported by a transparent polymer film, referred to as the first film, (non-adhe- sive, in particular polyester or polyolefin) preferably of a thickness of at least 20 pm, 30 pm or 40 pm and preferably of at most 200 pm, or better 125 pm or 100 pm or 75 pm (chosen according to its rigidity to facilitate manufacture of the laminated bilayer).

[0021] In the assembly step, the optical isolation layer is encapsulated between the thermoplastic reference interlayer sheet being part of the laminated bilayer and the other one of the first thermoplastic interlayer sheet and the lower interlayer sheet (i.e. the second thermoplastic interlayer sheet), referred to as the other thermoplastic interlayer sheet.

[0022] As can be taken from the following considerations, the inventive method simplifies and makes more reliable the manufacturing of an illuminable glass roof:

[0023] A major advantage is the production of the functional laminate upstream, so that only one element (i.e., the laminated bilayer) and the other thermoplastic interlayer sheet need to be positioned on the transparent reference sheet, rather than proceeding sheet-by-sheet, which considerably facilitates production of the illuminable laminated glass roof. The functional laminate can be prepared to be ready-to-use, e.g., available in rolls that can be unwound. In addition, as the functional laminate includes the optical isolation layer, a functional coating may be added to the second main face F2 if required (solar control, etc.). Further, a more reliable optical isolation layer may be provided. Stated more particularly, controlling the thickness of the optical isolation layer by coating the flexible polymer is much easier than coating of one of the transparent sheets. In addition, with the functional laminate rather than the sheet-by-sheet procedure, it is possible to laminate roof glasses of greater complexity without wrinkles being generated by the lamination in the thermoplastic interlayers.

[0024] Further, with the functional laminate, (partly) degassing can already be carried out during the bilayer formation phase.

[0025] The first film is chosen to be thin, in particular to limit the effect of local volume increase. The first film with an optical isolation coating or the optical isolation layer itself can be available in roll or sheet form. An individual thin first film would be difficult to handle, with the risk of flying off because it is too light, and would be subject to tearing when transported by robots, or would be cutting crease-prone, with creases and bumps when cut (during suction on a glazing cutter, etc.). Further, unstacking the first film into a sheet or extracting it from a roll would make it highly electrostatic, so that it attracts and catches dust, making it necessary to work in a very clean environment (especially in a clean room), or to add another electrostatic discharge step to cancel out the electrostatic forces pressing dust onto the first film. Conversely, as the first film is already protected by the thermoplastic reference interlayer sheet of the laminated bilayer, the unstacking or roll removal step does not mechanically alter the first film or impair its optical isolation function or transparency. Handling problems could also arise with the thermoplastic reference interlayer sheet alone, which can be as thin as 20 pm, in particular functionalized by carrying the light extraction layer. In addition, the thicker thermoplastic reference interlayer sheet facilitates crease- free cutting and crease-free placement not only of the first film but also of a possibly thin thermoplastic reference interlayer sheet.

[0026] In addition, all the layers of the functional laminate can be precisely positioned on the transparent reference sheet at the same time. In particular, in a sheet-to-sheet process, if the first film were alone, it would have to be cut to the shape of the glazing, and positioned correctly which adds steps to the process.

[0027] The use of a functional laminate according to the invention also reduces quality problems by reducing the number and interfaces of interleaved sheets, thus reducing the likelihood of trapping dust or fibers, which would lead to the disposal of products for appearance defects, once they have reached complete transparency at the end of the laminating process (degassing, autoclave). In addition, the quality of the functional laminate can be easily controlled further upstream in the roof manufacturing process, without sacrificing sheets of glass.

[0028] For optimum integration, the functional laminate may also contain the light extraction layer, which may not only be on the F3 side as in the prior art but can also be part of the functional laminate (i.e., laminated bilayer), in particular deposited on the first film (especially on an optical isolation coating) or can be deposited on the thermoplastic reference interlayer sheet. In particular, it may be desirable not to weaken the third main face F3 with such a coating.

[0029] The proposed solution therefore consists in preparing the functional laminate with the laminated bilayer (and even a functional laminate with one or more other sheets and / or bonded to other elements as described later) prior to placement on the transparent reference sheet, in order to reduce the number of process steps and duration, particularly in the cleanroom, and to facilitate handling and quality control.

[0030] Once the laminated bilayer is ready, it can be placed on the transparent reference sheet or placed on another sheet or, better still, in a stack of other sheets (also pre-assembled, etc.), in particular with one or more functional (electroactive, etc.) thermoplastic polymer films (non-adhesive), which can be bonded together before being placed on the transparent reference sheet. If necessary, prior to placement on the transparent reference sheet, the laminated bilayer is cut (partially or totally) and bonded with an interlayer frame at its periphery (contouring to the shape of the glazing).

[0031] The first film combined with the thermoplastic reference interlayer sheet provides sufficient adhesion thereto to allow cutting and handling and maintain good adhesion after lamination.

[0032] The functional laminate comprises a laminated bilayer which comprises two layers (i.e. the thermoplastic reference interlayer sheet and the optical isolation layer). The functional laminate may comprise more than two layers such as 3, 4, 5, 6, 7 layers, either integral or possibly laminated (at the same time as the laminated bilayer is formed), and / or an electroactive element. Accordingly, in the sense of the claimed invention, the functional laminate can be a laminated compound comprising the laminated bilayer and further layers laminated with laminated bilayer. The laminated bilayer may be integral part of the laminated compound comprised of the laminated bilayer and further layers. The thickness of the functional laminate in combination with the other thermoplastic interlayer sheet can be up to 8 mm or 6 mm. The length of the functional laminate can be at least 600 mm and at most 2000 mm. The width of the functional laminate can be at least 600 mm and at most 1500 mm to make it easier to handle and to be more compatible with roll-by-roll manufacture. For example, care is taken to ensure that the roll carrying the wound laminate is not too heavy and / or long. The other thermoplastic interlayer sheet may have a same length and width as the functional laminate.

[0033] The shape of the functional laminate can be customized to fit to the shape of the glazing and can, e.g., be quadrilateral, in particular rectangular, or have a rounded contour. The longitudinal edges of the functional laminate, like those of the glass sheets, can be straight or curved, in particular flared. The other thermoplastic interlayer sheet may be cut to be adapted to the shape of the functional laminate.

[0034] Preferably, the functional laminate is free of any additional glue (pressure-sensitive adhesive, etc.), the cohesion of the assembly and the adhesion between elements being achieved solely by the laminating interlayer adhesive material.

[0035] It is possible that after lamination of the glazing: the interface between the first thermoplastic interlayer sheet and the lower interlayer sheet (i.e., the second thermoplastic interlayer sheet) may be indistinguishable (especially if made from the same material and with the same tint), any interface between a thermoplastic interlayer frame and the first thermoplastic interlayer sheet or lower interlayer sheet (i.e., the second thermoplastic interlayer sheet) is indistinguishable (especially if based on the same material and tint), any interface between layers of a multi-layer interlayer frame is indistinguishable (especially if based on the same material and the same tint).

[0036] Naturally, the laminated bilayer in combination with the other thermoplastic interlayer sheet is a multilayer sheet obtained from foils.

[0037] The transparent reference sheet is preferably the second (i.e., inner) transparent sheet and presented with its convex surface facing upwards, as this facilitates positioning of the functional laminate. Positioning the initially flat functional laminate on a concave surface forces the functional laminate to curl up, creating ripples, whereas positioning it on a convex surface allows it to expand and deform more freely. Alternatively, the transparent reference sheet is the first (outer) transparent sheet and presented with its concave surface facing upwards.

[0038] The thermoplastic reference interlayer sheet can be the lower interlayer sheet (i.e., the second thermoplastic interlayer sheet), with the other thermoplastic interlayer sheet being positioned on the laminated bilayer sandwiching the optical isolation layer. Alternatively, the thermoplastic reference interlayer sheet can be the first thermoplastic interlayer sheet, with the lower interlayer sheet (i.e., the second thermoplastic interlayer sheet) being positioned on the transparent reference sheet and the laminated bilayer including the first thermoplastic interlayer sheet being positioned on the lower interlayer sheet sandwiching the optical isolation layer.

[0039] Before laminating, a glass assembly is formed, comprising first transparent sheet I other thermoplastic interlayer sheet I functional laminate I second transparent sheet. Other sheets may, e.g., be present between the first transparent sheet and the other thermoplastic interlayer sheet. Alternatively, a glass assembly is formed, comprising first transparent sheet I functional laminate I other thermoplastic interlayer sheet I second transparent sheet. Other sheets may, e.g., be present between the first transparent sheet and the functional laminate.

[0040] The glass roof is laminated at suitable temperatures and pressures (e.g., for PVB-based laminating interlayers by pressurizing preferably to at least 5 bar and at most 14 bar and heating to at least 100°C and at most 150°C, in particular by autoclaving).

[0041] Laminating may involve subjecting the glass assembly to a vacuum at room temperature to evacuate the air (degassing operation) between the two transparent glass sheets, then heating the glass assembly to a suitable temperature while continuing to subject it to a vacuum. In a step consisting of heating the glass assembly while subjecting it to a vacuum, no additional external pressure is simultaneously applied to it, as in an autoclave, for example. When the glass assembly is subjected to vacuum, the entire periphery of the glass assembly is tightly confined and the confined peripheral volume is sucked in. For example, the glass assembly is evacuated using a vacuum chamber or vacuum bag.

[0042] For laminating, for example, a sealed elastomer envelope is fitted over the entire periphery of the glass assembly, with an opening through which a vacuum is applied by suction. The tight envelope is often referred to as a "vacuum ring". The air between the two transparent sheets of glass is evacuated by cold suction over a period of 15 to 45 minutes, followed by heating to a temperature of 80 °C to 120 °C over a period of 30 to 60 minutes. Alternatively, the glass assembly can be placed in a vacuum chamber or vacuum bag, at least part of the walls of which are rigid so as to protect any peripheral elements of the glass assembly from physical contact under excessive mechanical stress. One example of a peripheral element is a connecting element connected to an electroactive element between two sheets of glass. For example, such a connecting or other element is between the two sheets and extends outside the glass assembly.

[0043] Preferably, after lamination, the first film does not extend to the edge of the glass, in particular its edge is protected by the thermoplastic interlayer material, avoiding edge sealing problems, lack of adhesion for the total glazing, water infiltration and oxidation.

[0044] In the present invention, for each sheet between the first and second glass sheets, rear main face means the face which is or is intended to be oriented towards face F3, front main face means the face which is or is intended to be oriented towards face F2.

[0045] In particular embodiments, the method for manufacturing an illuminable laminated glass roof for a vehicle may additionally include one or more of the following features, taken alone or in any technically possible combination.

[0046] In one embodiment, when in the laminated bilayer the first film has a free edge, the method comprises, prior to laminating of the sheets, a preferably direct bonding, without additional adhesive, of a thermoplastic interlayer frame (material identical or chemically compatible with the material of the first thermoplastic interlayer sheet and the lower interlayer sheet), preferably a monolithic interlayer frame (from a single layer), for handling, monolithic (in one piece) or in several abutting parts (or spaced apart by no more than 1 mm), with the laminated bilayer, preferably joined by local (point) bonds of an interlayer frame edge and the thermoplastic reference interlayer sheet, in particular by (local) softening of interlayer material (of the interlayer frame and / or the laminated bilayer).

[0047] (Local) softening can be achieved by applying a chemical solution such as alcohol, or preferably by local heating (application of heat to create cohesion between interlayer frame I thermoplastic reference interlayer sheet. Local bonding, in particular spot welding, is preferably carried out after (or at a later stage) the thermoplastic interlayer frame has been brought into contact (or within a maximum of 5 mm or 1 mm if locally heated) with the functional laminate, or with a cut-out part of the functional laminate (cut-out sheet). Preferably, at least 1 , 2, 3, 4 local bonds are made, in particular at least one per edge, and preferably local connections are at least 1 mm or 5 mm long and at most 30 mm or 15 mm wide, spaced at least 10 or 15 cm apart and even at most 80 or 50 cm apart.

[0048] The thermoplastic interlayer frame can be at least 20 mm wide (for integrity, handling and watertightness) and preferably be no wider than 100 mm or 50 mm, preferably with a thickness of at least 0.3 mm. It can be of sufficient width to secure a functional element such as a light redirection element as detailed later.

[0049] The method preferably comprises positioning the laminated bilayer with the thermoplastic interlayer frame integral with the laminated bilayer and the other thermoplastic interlayer sheet on the transparent reference sheet, wherein during lamination the free edge of the first film is encapsulated by laminating thermoplastic interlayer material.

[0050] In this way, bonding is preferably achieved by adhesive contact, not involving the addition of adhesive material, by (local) softening of thermoplastic interlayer material leading to adhesive contact between surfaces.

[0051] Advantageously, bonding (adhesive contact) is achieved by local heating and possibly also by pressure, such as induction heating, hot air or radiation (laser).

[0052] A metal pen, a "soldering iron" with a flat tip (and preferably with a non-stick film (silicone, Teflon®, polytetrafluoroethylene (PTFE), elastomer, etc.) capable of transmitting heat), one or more heating fingers (made of non-stick material, in particular silicone, Teflon®, PTFE, elastomer, etc.) or a hot-air gun can be used as a local or even multi-local heating (and preferably pressure) tool. Temperature and pressure are adjusted to suit the thermoplastic interlayer material (preferably PVB) and the tool. With a soldering iron, the temperature is at least 200 °C or 250 °C, and the welds are fast and deep, with no pressure required. Typically, with a soldering iron, the temperature is at least 200 °C or 250 °C, with heating fingers at least 100 °C.

[0053] Contact zones for local bonds can be centered a few mm from the boundary (junction or gap of no more than 1 mm) between thermoplastic interlayer frame and laminated bilayer and on either side of the boundary. For example, a 10 mm heating finger is centered alternately 5 mm from the boundary and on the laminated bilayer, and 5 mm from the boundary and on the thermoplastic interlayer frame.

[0054] Bonding (adhesive contact) can be carried out in a single operation for all local connections. A heating tool can be chosen to perform the various local adhesive points in a single operation, e.g., using heated fingers. Local heating can be achieved by applying a heating tool on the front side of the functional laminate (towards face F2) and / or on the rear side. This type of bonding is preferred to glue beading or double-sided adhesive bonding, which may be spot bonding. To be more compatible with the speed of an industrial line, the various local connections can be made between two elements in a single operation.

[0055] The thermoplastic interlayer frame is preferably a single piece, and even of constant thickness, but, if necessary, it can have strips (abutting or spaced by no more than 1 mm) forming the frame, for example one or more strips carrying a light redirection element.

[0056] Preferably, all laminating thermoplastic interlayer material is based on the same polymer, notably PVB, and, in particular with (sufficient) plasticizers for the thermoplastic interlayer frame and the thermoplastic reference interlayer sheet.

[0057] The thermoplastic interlayer frame can be a clear or tinted or even opaque sheet (for light masking, etc.).

[0058] Local heating can be used not only to form local adhesive contact between two elements, but also to secure a stack of several sheets together in pairs.

[0059] Advantageously, the method comprises positioning on the transparent reference sheet the laminated bilayer with the thermoplastic interlayer frame in integral form (linked by local bonds). For example, the method comprises: positioning of the laminated bilayer (previously cut) inside the thermoplastic interlayer frame (previously cut from a thermoplastic interlayer sheet), e.g., on an assembly table, securing the functional laminate (laminated bilayer) to the thermoplastic interlayer frame so that the edges of the thermoplastic interlayer frame and functional laminate are locally contiguous, positioning of the functional laminate bonded to the thermoplastic interlayer frame on the transparent reference sheet, centered with respect to the latter, or the functional laminate connected to the thermoplastic interlayer frame is placed on a sheet or stack of sheets and locally connected to this stack, and the integral assembly is placed on the transparent reference sheet with centering relative to the latter.

[0060] The other thermoplastic interlayer sheet is positioned on top or below the functional laminate having the thermoplastic interlayer frame bonded thereto.

[0061] In another embodiment, when in the laminated bilayer thickness is at most 200 pm and even at most 150 pm or 100 pm and the first film is shorter (for example by at least 3 mm, or 5 or 10 mm and at most 30 mm (possibly depending on the extent of the peripheral masking frame, defining the clear view) than the thermoplastic reference interlayer sheet and the other thermoplastic interlayer sheet, then after lamination of the glass assembly the first polymer film is already encapsulated by these thermoplastic interlayer sheets in adhesive contact with each other. This design does not require a (protective) interlayer frame. However, such an interlayer frame can be added to help center the functional laminate in the clear glass by reducing its extent, etc.

[0062] During laminating, care is to be taken to ensure that any thermoplastic interlayer material extends sufficiently and flows correctly to avoid breakage and bubbling. In particular, any functional element (first film, other functional polymer film, electroactive element etc.) with a thickness of at least 200 pm sandwiched between two or shorter thermoplastic interlayer sheets is preferably surrounded by a thermoplastic interlayer frame between the two thermoplastic interlayer sheets.

[0063] In particular, in the assembly process (with autoclaving), the interlayer material (PVB etc.) may eventually have difficulty flowing over distances of more than a few millimeters. Any local thickening of the glazing would lead to deformation of the first and second transparent sheets of glass. As a result, various undesirable phenomena could occur, such as: breakage of one of the two glass sheets due to excessive deformation of the glass sheets, inducing excessive local extension stresses; bubbles introduced into the glazing, due to imperfect flow of the thermoplastic interlayer material when the glazing is laminated; in particular, this lack of thermoplastic interlayer material or low partial pressure in the material encourages the formation of bubbles (by outgassing of the small molecules present in the PVB, etc.). In one embodiment, the method includes a partial peripheral (circumferential) cut of the first film leaving a frame surface protruding preferably by at least 20 mm (and preferably by at most 200 mm) from the thermoplastic reference interlayer sheet, wherein by placement of a laminating (thermoplastic) interlayer frame on the protruding frame surface, during lamination, together with the other thermoplastic interlayer sheet, the first film is encapsulated by laminating (thermoplastic) interlayer material.

[0064] In one embodiment, the method includes a peripheral cut of the bilayer resulting in a frame surface protruding from the other thermoplastic interlayer sheet, wherein by placement of a laminating (thermoplastic) interlayer frame on the protruding frame surface, during lamination, together with the other thermoplastic interlayer sheet, the first film is encapsulated by laminating (thermoplastic) interlayer material

[0065] In order to limit the risks of breakage or bubbling, a thermoplastic interlayer frame (preferably with a thickness of at least 0.3 mm to make it easier to handle without folds etc., with a width of at least 20 mm) is placed on the protruding frame surface. The thermoplastic interlayer frame is in contact with the cut sheet or spaced by no more than 5 mm or 1 mm and is edge to edge with the other thermoplastic interlayer sheet or offset by no more than 5 mm or 1 mm.

[0066] This thermoplastic interlayer frame can be used to protect the free edge of the first film as described above and / or to arrange a functional element (light redirection element, etc.) close to the laminated bilayer, and / or can be tinted or even opaque (to eliminate stray light etc.).

[0067] In particular, when the rear (free) face of the lower interlayer sheet (i.e., second thermoplastic interlayer sheet) does not carry the extraction layer, having a lower interlayer sheet in particular based on PVB with at least 20% plasticizers, it may be desirable for the rear (free) face of the lower interlayer sheet to have minimal roughness, favoring degassing and satisfactory lamination.

[0068] In particular, with a PVB base with at least 20% plasticizers, it may also be desirable for the front (free) face of the first thermoplastic interlayer sheet (facing the face F2 after placement on the transparent reference sheet) to have a minimum roughness, favoring degassing and satisfactory lamination. In particular, the roughness parameter Rz is at least 10 pm.

[0069] The functional laminate, or at least the laminated bilayer (preferably before any local bonding), can also be cut to a predetermined shape. Preferably, an automatic cutting system is used, itself consisting of a table, possibly a belt, a blade supported in an adjustable tool which is itself integral with a horizontal movement system (in X- Y) of the carriage type mounted on a bridge and making it possible to cut a thermoplastic interlayer sheet to form the thermoplastic interlayer frame and / or to cut the functional laminate (laminated bilayer). By combining the different movements, it is possible to have the blade follow any number of cutting trajectories. For example, a blade moves along the X axis of a bar and the bar moves along the Y axis of the plane. Preferably, the element to be cut is clamped by suction through holes in the belt.

[0070] In particular, in a first configuration for making the edges of the interlayers, the complete block is sized and positioned so that the edges of the various layers each have an overhang of between 5 and 20 mm with respect to the edges of the glass sheets, and, after autoclaving, the process includes brushing (removal) of excess PVB from the edge of the roof.

[0071] In particular, in a second configuration for making the edges of the interlayer, the complete block is sized and positioned so that the edges of the various layers have a recess of 0 to 4 mm relative to the edges of the glass sheets. No trimming or brushing is required here. The second configuration is preferred because having the interlayer frame edge slightly recessed in relation to the glass edge limits slight leakage through the glass edge. Further, the edges of the glass sheets are preferably encapsulated so that the glass edges are not visible. Moreover, not having to deburr or brush avoids operations and therefore yield losses, and deburring and brushing of several layers is more complex.

[0072] In one embodiment, the method includes a further step of, preferably direct, bonding, without additional adhesive, of at least one light redirection element (light redirected to face F3) with a thermoplastic interlayer material of the laminated bilayer (first thermoplastic interlayer sheet or lower interlayer sheet), in particular by local bonding(s). Additionally or alternatively, it may include a step of pre-bonding a light redirection element (light redirected to face F3) with a thermoplastic interlayer material of a thermoplastic interlayer frame (thermoplastic interlayer frame already connected to the laminated bilayer or subsequently connected to the laminated bilayer). Specifically, bonding may be reached by local connection(s), in particular by (local) softening of thermoplastic interlayer material of the laminated bilayer or prebonding by (local) softening of the thermoplastic interlayer frame. In particular, the local connection(s) is / are at least 1 mm or 5 mm and at most 10 mm long and spaced at least 10, 15 cm and at most 80, 50 cm apart. It may be desirable to limit the number of local connections so as not to alter the optical function of the light redirection element (transparency, etc.). For example, two local bondings may be envisaged.

[0073] The light redirection element is preferably < 200 pm thick to avoid the need for a thermoplastic interlayer frame, and is preferably a reflective prismatic film.

[0074] (Local) softening is achieved by application of a chemical solution such as alcohol, or preferably by local heating (generating adhesion, adhesive contact between light redirection element and thermoplastic interlayer material).

[0075] Local bonding, in particular spot welding, is preferably carried out after (or at a later stage) the light redirection element has been brought into contact with the thermoplastic interlayer material (or within a maximum of 5 mm, or 1 mm if locally heated). Preferably, the further bonding and / or pre-binding takes place prior to placement on the transparent reference sheet. During the lamination, the light redirection element may be encapsulated by thermoplastic interlayer material.

[0076] The light redirection element is able to receive light (by diode row(s) etc., normal or inclined) on the F4 side, passing through the second transparent sheet, and redirecting it towards the second transparent sheet in total reflection. The light redirection element is elongated to receive light from, for example, a row of diodes (straight bar of at least 5 cm, in one or more sections, connected or not). Preferably, the light redirection element is a reflective prismatic film at least 1 cm wide and at most 5 cm wide, and at least 5 cm long, comprising a flat face and a face with reflective prisms (monolithic or embossed film design). The light redirection element (the reflective prismatic film) preferably has a thickness of at most 200 pm to avoid the addition of a dedicated thermoplastic interlayer frame surrounding it.

[0077] Preferably, the prismatic part of the prismatic film is in contact with the thermoplastic interlayer material to protect peaks and even sinks into the thermoplastic interlayer material during lamination in the event of a slight over-thickness. The thickness of this material is preferably at least 25 pm, particularly preferably at least 50 pm or at least 100 pm.

[0078] The (first) reflective prismatic film can extend along a (first) longitudinal edge, preferably at a constant distance from the clear glass (inner edge of the peripheral masking frame) or from a lateral edge (at the front or rear of the roof). Several reflective prismatic films can be joined or separated along an edge. At least one further (second) reflective prismatic film can be added on a further (second) edge, in particular an opposite edge, in particular a similar or identic film, facing the (first) reflective prismatic film.

[0079] The light redirection element, in particular a prismatic film, can, e.g., be located under the first film or adjacent to the first film, possibly slightly offset in height from the first film.

[0080] In one embodiment, the light redirection element is a reflective prismatic film with a thickness of at most 200 pm or 150 pm and preferably at least 70 pm, wherein the reflective prisms are oriented towards the first thermoplastic interlayer sheet and the reflective prismatic film is positioned so as to face, abut or be offset (distant) by no more than 4 mm or 1 mm from the first film (with its outer edge), and any optical insulating coating is preferably up to the edge of the first film or set back no more than 1 mm from the edge of the first film.

[0081] Specifically, prior to bonding with the laminated bilayer, the method may comprise a step of contacting (laying) the prismatic reflective film on a rear main face of the lower interlayer (i.e., second thermoplastic interlayer sheet) intended to be oriented towards face F3, wherein the prismatic reflective film is preferably positioned to be at least partly facing the first film and, in particular, before laminating, the so-called smooth face of the prismatic film opposite the prisms is on face F3 (preferably in contact with). Alternatively, before or at the same time as bonding with the laminated bilayer, the method may comprise a step of pre-bonding of the reflective prismatic film with a front main face of a thermoplastic interlayer frame (before laminating, the so-called smooth face opposite the prisms is preferably placed directly on face F3), or within a multi-layered thermoplastic interlayer frame, preferably based on plasticized PVB.

[0082] The reflective prismatic film may be under the first film or adjacent to the first film, possibly slightly offset in height from the first film.

[0083] When the prismatic reflector film is positioned adjacent to the first film, or at a distance of no more than 4 mm or 1 mm, preferably the base or apex of the reflective prisms (facing the first thermoplastic interlayer sheet) of the prismatic reflector film is at most 30 pm above (the front face of) the optical isolation layer, in particular (the front face of) the first film. In one configuration, the reflective prismatic film can be positioned straddling the free rear face of the laminated bilayer and the rear face of the thermoplastic interlayer frame (in particular already integral with the laminated bilayer).

[0084] In one embodiment, the light redirection element is a reflective prismatic film, being of thickness of at least 70 pm and at most 200 or 150 pm, the method comprises placing the reflective prisms of the reflective prismatic film on a protruding surface of the laminated bilayer, after partial (circumferential) cutting of the laminated bilayer, on the rear main face of a thermoplastic interlayer frame (attached to the laminated bilayer or attached thereafter), or within a multi-layered thermoplastic interlayer frame (bonded, integral with the laminated bilayer.

[0085] Specifically, the thickness of the thermoplastic interlayer material accommodating the reflective prisms is at least 25 pm, better at least 100 pm, and preferably at most 400 pm. The reflective prismatic film may be under the first film or adjacent to the first film, possibly slightly offset in height from the first film.

[0086] When the reflective prismatic film is positioned adjacent to the first film, or at a maximum distance of 4 mm or 1 mm from the first film, then the bases or peaks of the reflective prisms (oriented towards the lower interlayer, towards face F3) are preferably at most 30 pm above (the front face) the first film or even the optical isolation layer (in the direction of face F2).

[0087] Prior to lamination, the reflective prisms may be oriented towards face F3.

[0088] Alternatively, the light source is on the F4 side and coupled to an F4-side transmission light redirection element (prism, prismatic film, etc.). The prismatic film (reflector or transmission, F4 side) and the first film can be partially or totally superimposed.

[0089] In one embodiment, the method comprises: providing a third thermoplastic interlayer sheet, placing on the third thermoplastic interlayer sheet, preferably in this order: a laminating (thermoplastic) interlayer frame, an additional functional element, which is an electroactive system, in particular based on liquid crystals, or another functional polymer film, positioning of the functional laminate on the additional functional element so that the thermoplastic interlayer frame is on the periphery of both the additional functional element and the functional laminate, bonding of the thermoplastic interlayer frame with the functional laminate and the third thermoplastic interlayer sheet, preferably by forming local bonds through local softening of the interlayer material by local heating.

[0090] To ensure that the various elements remain firmly attached and positioned in relation to one another during the rest of the process, they can also be joined by local bonding, i.e. (local) softening of the interlayer material. When the reference sheet is the second transparent sheet, the lower interlayer comes into contact with the F3 face, preferably bare, or with a functional coating (electrically conductive, transparent, etc.) on the F3 face. The edge of the functional is preferably under a peripheral masking frame, e.g., black enamel on face F2 and / or black ink on the third thermoplastic interlayer sheet or the first thermoplastic interlayer sheet.

[0091] In one embodiment, the method comprises, on the transparent reference sheet, which is the second sheet, the positioning of a light redirection element such as a reflective prismatic film with a textured face and a smooth opposite face on the third main face F3. Specifically, a thermoplastic interlayer frame surrounding the light redirection element may be envisaged.

[0092] The light extraction layer is preferably a diffusing coating which is: between the optical isolation layer and the lower interlayer (i.e., second thermoplastic interlayer sheet) with a coverage rate preferably of at most 30% (for cohesion), on the rear face of the lower interlayer (F3 side) with a coverage rate of preferably no more than 30%, no more than 25%, 10% (for cohesion).

[0093] Each laminating (thermoplastic) interlayer sheet made of thermoplastic polymeric material may be selected from polyvinyl butyral (PVB), PVA, ethylene-vinyl acetate (EVA), polyurethane (TPU) alone or in blends of several varieties of one and / or several of these; the term "varieties" here refers to variations in plasticizer content, branching / linearity, average molecular weight of the molecules, and so on. It may be preferable for each thermoplastic interlayer sheet to be based on the same thermoplastic polymer (plasticized or not, tinted or not, etc.).

[0094] If required, one of the thermoplastic interlayer sheets can be an acoustic PVB, in particular the third thermoplastic interlayer sheet or the first thermoplastic interlayer sheet (outermost thermoplastic interlayer sheet, i.e. in contact with face F2, bare or coated) or the bottom thermoplastic interlayer sheet (in contact with face F3). In this configuration, therefore, the acoustic interlayer sheet is multi-layered. The lower interlayer is clear, while the first thermoplastic interlayer sheet can be clear or tinted. For a clear interlayer, a light transmission of at least 90% is preferred. The thermoplastic interlayer frame can be tinted (in whole or in part) or even opaque.

[0095] The electroactive element (or any additional film) need not be the same size as the interlayer (it may be longer or shorter along all or part of its edge). In any case, it is preferred that the edges of the laminated bilayer and of the electroactive element, of the third thermoplastic interlayer sheet (and even the interlayer frame(s) and any light redirection element, in particular a reflective prismatic film) be masked from the outside by a peripheral masking frame and even from the inside, for example by a trim.

[0096] In one embodiment, the optical isolation layer comprises an optical isolation coating, in particular a matrix with porosities or hollow spheres on a main, preferably rear, face of the first film, the first film is preferably a polyester film, in particular PET, or polyolefin, with thickness of 50 pm to 100 pm.

[0097] The invention further relates to a functional laminate, in particular, usable in the method according to the invention as described above, preferably with a thickness of no more than 8 mm or even no more than 6 mm including a laminated bilayer comprising: one of a first thermoplastic interlayer sheet and a second thermoplastic interlayer sheet, referred to as thermoplastic reference interlayer sheet, with the first thermoplastic interlayer sheet preferably having a thickness of at least 0.3 mm (single- or multi-layer, particularly if acoustic PVB), and the second thermoplastic interlayer sheet preferably having a thickness of at least 20 pm (single- or multi-layer, especially if acoustic PVB), an optical isolation layer comprising or supported by a transparent thermoplastic polymer film, referred to as the first film, preferably with a thickness of at least 20 or 50 pm and at most 200 pm or 125 or 100 pm. In one embodiment, the functional laminate carries a light extraction layer, preferably in the form of a diffusing coating on the rear face (intended to be oriented towards face F3 or between the optical isolation layer and the lower interlayer sheet, i.e. second thermoplastic interlayer sheet).

[0098] The first film, preferably PET, has an adhesion with the thermoplastic reference interlayer sheet preferably of at least 2 N / m. A light transmission of the first film (and of the thermoplastic reference interlayer sheet) of at least 90% is preferred, with a haze of at most 0.5% (measured according to ASTM D 1003).

[0099] The optical isolation coating can be an organic (cross-linked material etc.) or inorganic (silica etc.) matrix with porosities or hollow nanoparticles (silica etc.) or (sufficiently) low refractive index by its matrix itself. Preferably, the optical isolation coating is a hard coat, thanks to its matrix, in particular a hard coat that is not susceptible to damage by calender lamination. The optical isolation coating therefore preferably has a hardness of at least 1 H. If necessary, it is covered by a (more) hard, transparent protective coating, e.g. a dense layer, preferably at least 1 pm thick.

[0100] The first film can also be a fluoropolymer film preferably with a thickness of at most 100 pm, in particular FEP etc., preferably corona-treated, wherein the thermoplastic interlayer material of the laminated bilayer preferably is PVB-based for better adhesion.

[0101] In particular, the light extraction layer can, e.g., be a scattering coating (matrix with scattering particles) on the optical isolation coating with a possible protective overcoat on the optical isolation coating (porous etc.). Preferably, the scattering coating is a hard coat, thanks to its matrix, in particular one that is not susceptible to damage during calender lamination, and is not susceptible to sticking (by calender, roll-to-roll, etc.), e.g. an anti-stack varnish. In this way, the scattering coating preferably has a hardness H of at least 1 H.

[0102] In particular, the lower interlayer sheet (i.e. second thermoplastic interlayer sheet) can be based on, preferably made of, PVB with 0% to 15% plasticizers, with a thickness of at most 50 pm and can carry the scattering coating on the front or rear main face.

[0103] The functional laminate may comprise the laminated bilayer or even 3, 4, 5, 6, 7 laminated layers, preferably at most 1 or 2 additional interlayer sheets, 1 or 2 functional films, and / or an electroactive element. In particular, the multilayer is laminated and comprises a functional polymer film, e.g., a solar control film (e.g., with an electroconductive, solar control or coextruded coating etc.) and a third thermoplastic interlayer sheet. Laminating by calendering is preferred for certain electroactive systems, in particular those based on liquid crystals or solar cells. The laminated functional laminate can include a thermoplastic interlayer frame around the circumference of the multilayer and locally in adhesive contact with the multilayer.

[0104] The functional laminate may comprise at least one light redirection element (as already described), in particular with a thickness of at least 70 pm and at most 200 pm, and, in particular thermoplastic interlayer material (of the laminated bilayer and / or of a thermoplastic interlayer frame integral with the laminated bilayer) is locally in adhesive contact with the light redirection element.

[0105] The cut functional laminate may have an overhanging frame surface filled by a thermoplastic interlayer frame of variable tint, which may be opaque over all or part of its thickness. The thermoplastic interlayer frame carrying the light redirection element may comprise an opaque zone (in bulk, e.g. black PVB, or black coating) facing the light redirection element, between the prisms and face F2. The multi-layer carrying the light redirection element may comprise an opaque zone (opaque PET or coating, still black) facing the light redirection element, between the prisms and face F2.

[0106] The functional laminate can include any electroactive system suitable for calender lamination (electroactive system in sheet form upstream of the calender or by unwinding a roll), in particular an electroactive system comprising a first polymeric film (or thin glass), in particular polyester (PET etc.), with an electrically conductive layer (ITO, silver etc.), an electrochromic layer in allsolid technology and a second polymeric film (or thin glass).

[0107] The invention also relates to a roll comprising the functional laminate as described above in wound strip form (before cutting). Specifically, the functional laminate includes a laminated bilayer preferably with a width of at least 600 mm, a length of at most 500 mm or even 300 or 200 mm.

[0108] Further, the invention relates to a method for manufacturing a functional laminate according to the invention which optionally comprises forming a roll of the functional laminate as described above preferably via a roll-to-roll method. Embodiments of the method for manufacturing an illuminable laminated glass roof for a vehicle according to the invention as described above comprise the manufacturing of a functional laminate. Accordingly, one or more embodiments of the method for manufacturing a functional laminate may be part of the method for manufacturing an illuminable glass roof for a vehicle.

[0109] The method comprises: continuous pulling of the optical isolation layer in strip form, wherein the first film is a fluoropolymer film or a transparent polymer film carrying an optical isolation coating, continuous pulling of one of a first thermoplastic interlayer sheet in strip form and a second thermoplastic interlayer sheet in strip form, referred to as the thermoplastic reference interlayer sheet, preheating of the thermoplastic reference interlayer sheet in strip form, forming the functional laminate by calendering the preheated thermoplastic reference interlayer sheet and the first film, optionally, winding the functional laminate onto a winding roll.

[0110] Accordingly, manufacture of the bilayer starts with the provision of the sheets of the bilayer which may, for example, be made by extrusion. The thermoplastic reference interlayer sheet and / or first film could come directly from an extrusion or other manufacturing method eliminating the need for roll unwinding. Otherwise, the thermoplastic reference interlayer sheet and / or first film can be provided in wound form on one or more rolls.

[0111] Preferably, the steps are performed from roll to roll (from several rolls of sheets to the functional laminate roll, in a single continuous roll-to-roll process or several successive roll-to-roll processes), preferably at a speed of at least 1 or 10 or 20 m / min. It is highly advantageous to produce the functional laminate using a roll-to-roll method, rather than sheet-to-sheet assembly followed by lamination (by autoclave, etc.), as handling of thin films during roof manufacturing is improved, limiting the risk of pollution of thin films, limiting wrinkling, and reducing waste. Furthermore, the use of rolls is compatible with industrial production rates and can readily be automated. It is also preferable to use rolls of the thermoplastic reference interlayer sheet and polymer film rather than pre-cut sheets conveyed to the calender. A temporary polymeric protective film (e.g. polyethylene, PE, strip unwound from a PE roll) can be inserted before winding the functional laminate, so that the free face of the outermost interlayer sheet is not in contact with each other.

[0112] Preheating of the thermoplastic reference interlayer sheet serves to make the interlayer tacky (for adhesion to the fluoropolymer film or the transparent polymer film, respectively). Specifically, if the thermoplastic reference interlayer sheet is PVB-based, preheating of the thermoplastic reference interlayer sheet is at least 50 / 60°C and at most 120°C. For preheating of the thermoplastic reference interlayer sheet any means known to the skilled person can be used, such as, but not limited to, hot air, infrared lamps, in particular a plurality of IR lamps across the width of the sheet, in particular IR resistors, microwave and passage between heating rollers.

[0113] The functional laminate is formed by calendering, i.e., pressing the preheated reference interlayer sheet and the first film between two rotating, gap-adjusted contra rolls. Calendering takes place as soon as possible after the heating phase, e.g. < 5 sec, preferably at room temperature. Cooling of the functional laminate can be envisaged prior to winding, e.g., by passing over cooled roll(s).

[0114] Basically, the tension (in N / m) of the sheet unwind from a roll is controlled to unwind it correctly, maintaining the tension in the sheet to ensure that the sheet is held in place across its entire width, while avoiding elongation of the material. The (linear) pressure applied by the calender preferably is no more than 3500 N / m. The temperature of the PVB on arrival at the press roller, is minimum 70 °C.

[0115] In particular, the method may comprise pre-cutting on one or both free edges of the continuously laminated bilayer after calendering and before winding, and even followed by lateral cutting for storing and / or transporting the roll.

[0116] The method may further involve: unwinding a roll containing a thermoplastic film in strip form, liquid deposition of an isolation composition to form an optical isolation coating, notably porous or with hollow particles, optional liquid deposition of a hard protective overcoat, liquid deposition on the optical isolation coating (directly or on the overcoat) of a composition known as an extractant composition comprising a matrix that is notably organic, crosslinkable (in particular by UV, photo or thermo-crosslinking) and scattering particles, forming one or more patterns, to form the light extraction layer (after curing, crosslinking).

[0117] Due to the relaxation of the interlayer material (PVB with little or no plasticizer), deposition of the optical isolation coating takes place (at room temperature) before the calendering or even preheating process. The main known techniques for depositing a liquid composition are flow coating, dip coating, screen printing, and digital or inkjet printing. In particular, deposition can be carried out by spin coating, film puller, curtain or slot die, Meyer bar or gravure printing. In one embodiment, deposition is by means of a Meyer bar consisting of a cylindrical core surrounded by a spiral. The thickness of the deposit depends essentially on the spacing of the spirals and the diameter of the rod constituting these spirals, i.e. the depth of the cylindrical core in relation to the (outer) contact surface of the spirals. The result is a controlled thickness of liquid deposit.

[0118] In one embodiment, the method comprises a step of applying a light-extraction layer to the thermoplastic reference interlayer sheet or to the optical isolation layer in the form of a scattering coating preferably with a coverage rate of at most 30%. The extraction pattern can be carried either by the transparent polymer film (possibly already with isolation layer in the form of a coating), or by the lower interlayer sheet. Deposition of the extractant composition takes place in a clean environment so as not to trap particles (during curing). Preferred techniques for depositing the extractant composition include flexography, heliogravure and inkjet printing.

[0119] The invention further relates to an illuminable laminated glass roof obtainable (i.e. obtained) by the method according to the invention as described above.

[0120] Further features and advantages of the present invention will be apparent from the description below, with reference to the attached figures which illustrate non-limiting examples of its implementation. In the figures:

[0121] Figs. 1A-1 B show schematic sectional views of an illuminable laminated glass roof without (Fig. 1A) and with (Fig. 1 B) an optical isolation layer;

[0122] Fig. 2 shows a schematic roll-to-roll process for manufacturing the functional laminate;

[0123] Figs. 3A-3F show schematic sectional views of various embodiments of the functional laminate;

[0124] Figs. 4A-4C show schematic sectional views illustrating the creation of a recess in the func- tional laminate and the arrangement of an interlayer frame in the recess; Figs. 5A-5B show various embodiments of arranging the functional laminate in an interlayer frame;

[0125] Fig. 6 shows a schematic sectional views of an exemplary illuminable laminated glass roof;

[0126] Fig. 7 shows a schematic top view of the illuminable laminated glass roof of Fig. 6.

[0127] The invention is now described in more detail and in a non-limiting manner in the following description. The invention relates primarily to a method for manufacturing an illuminable laminated glass roof for a vehicle, in particular a road vehicle.

[0128] Reference is first made to Figs. 1A and 1 B illustrating the basic principle of using an optical isolation layer in an illuminable laminated glass roof, in total denoted by reference numeral 100, of a vehicle. The laminated glass roof 100 comprises an outer glass 101 , an inner glass 102 and a transparent polymeric interlayer 103 for bonding the outer glass 101 and inner glass 102 in a laminated manner. Specifically, as is known to the skilled person, the light of a diode 104 can be injected to the inner glass 102, e.g., located at the edge of the glass roof 100. The light can be reflected with an appropriate angle into the inner glass 102 by a light redirection element 105, e.g., configured as prismatic film and, e.g., positioned on face F3 of the inner glass 102. The light is then guided in the inner glass 102 by total internal reflection and extracted towards the vehicle interior by a light extraction layer 106, i.e. , an extraction pattern, e.g., configured as enamel, ink or texture, e.g., comprising plural light extraction areas 107 which scatter the light in various directions so that it can be seen in the interior of the vehicle.

[0129] When guiding the light into the inner glass 102 surrounded by air on face F4 and an interlayer 103 made of PVB on face F3 by total internal reflection, only light having an angle superior to 78° with regards to the glass normal direction is guided within the inner glass 102. As illustrated in Fig. 1 B, adding an optical isolation layer 108 having a lower refractive index relative to the inner glass 102 and relative to the interlayer 103 increases the admissible angles of total internal reflection and thus the amount of guided light. A technical solution for this is to, e.g., add a PET layer coated with a low Rl coating, or a layer of fluoropolymer. As the adhesion between the coated PET layer and glass is poor or non-existent, an additional bounding layer, e.g., made of PVB, is needed to guaranty the cohesion of the glazing. According to the invention, a method for manufacturing an illuminable glass roof for a vehicle comprising an optical isolation layer is disclosed.

[0130] With particular reference to Fig. 6 an exemplary embodiment of a glass roof 1 manufactured by the method according to the invention is disclosed. As is illustrated, the glass roof 1 comprises an outer glass 2 made of clear mineral glass, an inner glass 3 made of clear mineral glass and a transparent polymeric interlayer 4 comprising various thermoplastic interlayer sheets for bonding the outer glass 2 and the inner glass 3 in a laminated manner. Specifically, the polymeric interlayer 4 comprises a first thermoplastic interlayer sheet 5, which in this embodiment is an intermediate interlayer sheet, a second thermoplastic interlayer sheet 6 and a third thermoplastic interlayer sheet 7. An electro-optical element 8 such as a PDLC-layer allowing to regulate the optical transmission of the glass roof 1 based on an electric voltage applied is sandwiched between the third thermoplastic interlayer sheet 7 and the second thermoplastic interlayer sheet 6. The electro- optical element 8 is surrounded by a thermoplastic interlayer frame 9 with the electro-optical element 8 being accommodated in a cut-out of the interlayer frame 9. The second thermoplastic interlayer sheet 6 extends between the first thermoplastic interlayer sheet 5 and the third main face F3 of the inner glass 3.

[0131] The glass roof 1 further comprises several light redirection elements 10 for redirecting light into the inner glass 3 for total internal reflection therein as well as a light extraction layer 13 comprising plural light extraction areas 14. The glass roof 1 also comprises an optical isolation layer 11 , which in this embodiment is configured as coating on a carrier layer 12. The light extraction layer 13 is in contact with the second thermoplastic interlayer sheet 6 and arranged between the optical isolation layer 11 and the third main face F3 of the inner glass 3.

[0132] The first thermoplastic interlayer sheet 5 and the third thermoplastic interlayer sheet 7 may, e.g., be made of grey PVB having a thickness of 0.38 mm. The second thermoplastic interlayer sheet 6 and the frame layer 9 may, e.g., be made of clear PVB having a thickness of 0.38 mm. The carrier layer 12 may, e.g., be made of PET having a thickness of 100 pm. The optical isolation layer 11 is arranged on the face of the carrier layer 12 directed to the inner glass 3. The light extraction areas 14 may be configured as printed areas on the carrier layer 12 on the face directed to the inner glass 3. The optical isolation layer 11 has a refractive index in the visible range which is smaller than the refractive index of the first thermoplastic interlayer sheet 5. The method for manufacturing the glass roof 1 comprises an assembly step comprising positioning on one of the outer glass 2 and the inner glass 3 the first thermoplastic interlayer sheet 5, the second thermoplastic interlayer sheet 6, the third thermoplastic interlayer sheet 7, the electro- optical element 8 being sandwiched between the first thermoplastic interlayer sheet 5 and the third thermoplastic interlayer sheet 7, the light redirection elements 10, the carrier layer 10 with coating (optical isolation layer 11) and printed light extraction layer 13, positioning of the other one of the outer glass 2 and the inner glass 3, and laminating the sheets.

[0133] Specifically, the assembly step comprises positioning of a functional laminate 23 including a laminated bilayer 15, which comprises one of the first thermoplastic interlayer sheet 5 and the second thermoplastic interlayer sheet 6 and the carrier layer 12 with coating (optical isolation layer 11) and printed light extraction layer 13. In this embodiment, the functional laminate 23, i.e. , the laminated bilayer 15, e.g., comprises the first thermoplastic interlayer sheet 5 and the carrier layer 12 with coating (optical isolation layer 11) and printed light extraction layer 13. In this embodiment, the light redirection elements 10 are configured as reflective prismatic films and respectively comprise a flat base 16 and plural prisms 17 for reflecting the light and are bonded to the laminated bilayer 15 by means of the base 16.

[0134] With particular reference to Fig. 2, the functional laminate 23 (laminated bilayer 15) can be produced in a roll process. Stated more particularly, the first thermoplastic interlayer sheet 5 is pulled from a roll 18' and the carrier layer 12 coated with the optical isolation layer 11 and provided with the printed light extraction layer 13 is pulled from a roll 18", with the first thermoplastic interlayer sheet 5 being heated by a heater 19. Both the heated first thermoplastic interlayer sheet 5 and the carrier layer 12 are guided through a pair of nip rollers 20 which can be pressed against each other as illustrated by the arrows so that the sheets are bonded together to form the laminated bilayer 15. The first thermoplastic interlayer sheet 5 is, e.g., heated to a temperature of ca. 60 °C. The functional laminate 23 (bilayer 15) is wound to a roll 18.

[0135] Reference is now made to Figs. 3A through 3F illustrating various embodiments of the functional laminate 23. In Fig. 3A, the bilayer 15 comprises the first thermoplastic interlayer sheet 5 and the carrier layer 12 which is coated with the optical isolation layer 11. The optical isolation layer 11 is arranged at the side of the carrier layer 12 facing away from the first thermoplastic interlayer sheet 5. The first thermoplastic interlayer sheet 5 may, e.g., consist of grey PVB having a thickness of 0.38 mm. The carrier layer 12 may consist of coated PET having a thickness of or smaller than 100 pm. In Fig. 3B, the bilayer 15 differs from the bilayer 15 of Fig. 3A in having a carrier layer 12 which is provided with the light extraction layer 13 comprising plural light extraction areas 14. The light extraction areas 14 are printed on the carrier layer 12 at the side facing away from the first thermoplastic interlayer sheet 5.

[0136] In Fig. 3C, the bilayer 15 differs from the bilayer of Fig. 3B by being bonded to the second thermoplastic interlayer sheet 6. The second thermoplastic interlayer sheet 6 may, e.g., consist of clear PVB, having a thickness of 0.38 mm, with the carrier layer 12 consisting of coated and printed PET having a thickness of e.g. 125 pm. Alternatively, the second thermoplastic interlayer sheet 6 may, e.g., consist of clear PVB, having a thickness of 0.7 mm, with the carrier layer 12 consisting of coated and printed PET having a thickness of e.g. 75 pm.

[0137] In Fig. 3D, the bilayer 15 differs from the bilayer of Fig. 3C by having a carrier layer 12 consisting of coated PET, with the light extraction layer 13 comprising plural light extraction areas 14 being printed on the second thermoplastic interlayer sheet 6 at the side facing away from the carrier layer 12.

[0138] In Fig. 3E, the bilayer 15 comprises the second thermoplastic interlayer sheet 6 and the optical isolation layer 11 which in this embodiment is a layer of fluoropolymer having a thickness of, e.g., 50 pm. The second thermoplastic interlayer sheet 6 may, e.g., consist of clear PVB, having a thickness of 25 pm and is provided with the light extraction layer 13 comprising plural light extraction areas 14 being printed on the second thermoplastic interlayer sheet 6 at the side facing away from the optical isolation layer 11.

[0139] In Fig. 3F, the bilayer 15 differs from the bilayer of Fig. 3E by having a carrier layer 12 consisting of PET and being coated with the optical isolation layer 11 , with the optical isolation layer 11 being arranged at the side facing towards the second thermoplastic interlayer sheet 6.

[0140] In the bilayer 15, the coated and optionally printed carrier layer 12 can have a free edge or can be selectively cut to produce a recess. This is illustrated in Figs. 4A through 4C. Specifically, in the bilayer 15 as embodied in Fig. 3A the coated carrier layer 12 is cut by a blade 22 in order to create the recess 21. The adhesion between the different layers is chosen to allow both cutting and peeling without tearing-off the stack. If the peeled-off part is thin enough, there is no need to compensate the remaining thickness with an interlayer frame. If the peeled-off part is thick, it should be compensated by an interlayer frame 9'. Further, the interlayer frame 9' can be chosen such that it also has another function, for example be black so that it blocks parasitic light.

[0141] Alternatively, the bilayer 15 can be cut to shape and arranged in a cut-out of interlayer frame 9". Specifically, if the thickness of the bilayer 15 allows to be compensated by a standard thickness of PVB layer (0.38 mm or 0.51 mm or 0.76 mm or 0.81 mm), the bilayer 15 can be cut to shape and integrated inside the interlayer frame 9". This is illustrated in Figs. 5A and 5B. Specifically, the embodiment of the bilayer 15 of Fig. 3C is accommodated in interlayer frame 9". In the embodiment of Fig. 5A, the second thermoplastic interlayer sheet 6 may consist of clear PVB and have a thickness of 0.38 mm, with the coated and printed carrier layer 12 having a thickness of 125 pm. The interlayer frame 9" may consist of PVB and have a thickness of 0.51 mm. In the embodiment of Fig. 5B, the second thermoplastic interlayer sheet 6 may consist of clear PVB and have a thickness of 0.7 mm, with the coated and printed carrier layer 12 having a thickness of 75 pm. The interlayer frame 9" may consist of PVB and have a thickness of 0.76 mm.

[0142] In above embodiments, the interlayer frame 9', 9" can be bonded to the bilayer 15 by thermal (direct) bonding at one or plural spots without using further adhesive.

[0143] Fig. 7 shows a schematic top view of the illuminable laminated glass roof of Fig. 6. As can be seen, the width w1 of the thermoplastic interlayer sheets 5-7 is broader than the width w2 of the functional laminate 23, i.e., bilayer 15. In other words, the functional laminate 23, i.e., bilayer 15, is cut-back in relation to the thermoplastic interlayer sheets 5-7.

[0144] As can be seen from the above description, the present invention discloses a method for manufacturing an illuminable laminated glass roof for a vehicle, in particular a road vehicle, which is very effective in terms of improving handling of the thin sheets and avoiding problems related therewith. Further, the illuminable laminated glass roof for a vehicle can be manufactured in an easy, time- and cost-efficient manner. List of reference signs

[0145] 1 Glass roof

[0146] 2 Outer glass

[0147] 3 Inner glass

[0148] 4 Interlayer

[0149] 5 First thermoplastic interlayer sheet

[0150] 6 Second thermoplastic interlayer sheet

[0151] 7 Third thermoplastic interlayer sheet

[0152] 8 Electro-optical element

[0153] 9, 9', 9" Interlayer frame

[0154] 10 Light redirection element

[0155] 11 Optical isolation layer

[0156] 12 Carrier layer

[0157] 13 Light extraction layer

[0158] 14 Light extraction area

[0159] 15 Bilayer

[0160] 16 Base

[0161] 17 Prism

[0162] 18,18', 18" Roll

[0163] 19 Heater

[0164] 20 Nip roller

[0165] 21 Recess

[0166] 22 Blade

[0167] 23 Functional laminate

[0168] 100 Glass roof

[0169] 101 Outer glass

[0170] 102 Inner glass

[0171] 103 Interlayer

[0172] 104 Diode

[0173] 105 Light redirection element

[0174] 106 Light extraction layer

[0175] 107 Light extraction area

[0176] 108 Optical isolation layer

Claims

1 . A method for manufacturing an illuminable laminated glass roof (1) for a vehicle, comprising: a first transparent sheet (2) made of mineral glass, with a first main face F1 , a second opposing main face F2, intended to form an exterior glass, a transparent polymeric interlayer (5-6), comprising a first thermoplastic interlayer sheet (5) and a second thermoplastic interlayer sheet (6), a second transparent sheet (3) made of mineral glass or polymer, with a third main face F3 and an opposing fourth main face F4, with a refractive index n1 in the visible range, an optical isolation layer (11), transparent, with a refractive index n2 in the visible range such that n2 < n1 , a light extraction layer (13), wherein the second thermoplastic interlayer sheet (6) extends between the first thermoplastic interlayer sheet (5) and the third main face F3, the light-extraction layer (13) being in contact with the second thermoplastic interlayer sheet (6) and arranged between the optical isolation layer (11) and the third main face F3, the method comprising: an assembly step, comprising: positioning of the first thermoplastic interlayer sheet (5) and the second thermoplastic interlayer sheet (6) on one of the first and second transparent sheets (2, 3), referred to as the transparent reference sheet, positioning of the other one of the first and second transparent sheets (2, 3), referred to as the other transparent sheet, laminating the sheets, characterized in that the assembly step comprises placing on the transparent reference sheet a functional laminate (23) including a laminated bilayer (15), said laminated bilayer (15) comprising: one of the first thermoplastic interlayer sheet (5) and the second thermoplastic interlayer sheet (6), referred to as the thermoplastic reference interlayer sheet, said optical isolation layer (11), which comprises or is supported by a transparent polymer film, referred to as the first film, with said optical isolation layer (11) being arranged between the thermoplastic reference interlayer sheet and the other one of the first thermoplastic interlayer sheet (5) and the second thermoplastic interlayer sheet (6), referred to as the other thermoplastic interlayer sheet.

2. The method for manufacturing an illuminable laminated glass roof (1) of a vehicle according to claim 1 , characterized in that it comprises, prior to laminating the sheets, adhesive bondingof a thermoplastic interlayer frame (9', 9") to the laminated bilayer (15), with said thermoplastic interlayer frame (9', 9") surrounding the first film.

3. The method for manufacturing an illuminable laminated glass roof (1) of a vehicle according to claim 1 or 2, characterized in that it comprises i) a partial peripheral cut of the first film leaving a frame surface protruding from the thermoplastic reference interlayer sheet, wherein by placement of a thermoplastic interlayer frame on the protruding frame surface, during lamination, together with the other thermoplastic interlayer sheet, the first film is encapsulated by thermoplastic interlayer material, and / or ii) a peripheral cut of the laminated bilayer resulting in a frame surface protruding from the other thermoplastic interlayer sheet, wherein by placement of a thermoplastic interlayer frame on the protruding frame surface, during lamination, together with the other thermoplastic interlayer sheet, the first film is encapsulated by thermoplastic interlayer material.

4. The method for manufacturing an illuminable laminated glass roof (1) of a vehicle according to any one of claims 1 through 3, characterized in that it comprises: providing of at least one light redirection element (10), bonding of said light redirection element (10) with the laminated bilayer (15) by forming local bond(s) by local softening of the thermoplastic interlayer material of the laminated bilayer, preferably by local heating, preferably prior to placement on the transparent reference sheet, and / or bonding of said light redirection element (10) with an thermoplastic interlayer frame by forming local bond(s) by local softening of the thermoplastic interlayer frame, preferably by local heating, preferably prior to placement on the transparent reference sheet.

5. The method for manufacturing an illuminable laminated glass roof (1) of a vehicle according to claim 4, characterized in that the light redirection element (10) is a reflective prismatic film comprising a textured main face with reflective prisms (17) and an opposite main face referred to as the smooth face, preferably having a film thickness of at most 200 pm, with said textured main face being oriented towards the first thermoplastic interlayer sheet (5), wherein the reflective prismatic film is positioned so as to face, adjoin or be offset by at most 4 mm with the first film.

6. The method for manufacturing an illuminable laminated glass roof of a vehicle according to claim 4, characterized in that the light redirection element (10) is a reflective prismatic film having a textured main face with reflective prisms (17) and an opposite main face referred to asthe smooth face, the reflective prismatic film preferably being of thickness of at least 70 pm and at most 200 pm, the method comprising placing the reflective prismatic film: on a protruding frame surface of the laminated bilayer (15), after partial cutting of the laminated bilayer, or on a rear main face of an interlayer frame, the rear main face being intended to face the third main face F3, or within a laminated interlayer frame, in particular a multi-layered frame.

7. The method for manufacturing an illuminable laminated glass roof (1) of a vehicle according to any one of claims 1 through 6, characterized in that it comprises: providing a third thermoplastic interlayer sheet (7), placing on the third thermoplastic interlayer sheet (7), preferably in this order: a thermoplastic interlayer frame, an additional functional element (8), which is an electroactive system, in particular based on liquid crystals, or another functional polymer film, positioning of the functional laminate on the additional functional element (9) so that the thermoplastic interlayer frame is on the periphery of both the additional functional element (9) and the functional laminate, bonding of said thermoplastic interlayer frame with the functional laminate and the third thermoplastic interlayer sheet (7), preferably by forming local bonds through local softening of the interlayer material by local heating.

8. The method for manufacturing an illuminable laminated glass roof (1) of a vehicle according to any one of claims 1 through 7, characterized in that it comprises, on the transparent reference sheet, which is the second transparent sheet, the positioning of a light redirection element (10), such as a reflective prismatic film with a textured face and a smooth opposite face on the third main face F3.

9. The method for manufacturing an illuminable laminated glass roof (1) according to any one of the preceding claims 1 through 8, comprising for manufacturing of the functional laminate (23): continuous pulling of the optical isolation layer (11) in strip form, wherein the first film is a fluoropolymer film or a transparent polymer film (12) carrying an optical isolation coating,continuous pulling of one of the first thermoplastic interlayer sheet (5) in strip form and the second thermoplastic interlayer sheet (6) in strip form, referred to as the thermoplastic reference interlayer sheet, preheating of the thermoplastic reference interlayer sheet in strip form, forming the functional laminate (23) by calendering the preheated thermoplastic reference interlayer sheet and the first film, optionally, winding the functional laminate (23) onto a winding roll (18).

10. The method for manufacturing an illuminable laminated glass roof (1) according to claim 9, comprising applying of at least one light-extraction layer (10) to the thermoplastic reference interlayer sheet or to the optical isolation layer (11) in the form of a scattering coating preferably with a coverage rate of at most 30%.

11. The method for manufacturing an illuminable laminated glass roof (1) according to any one of the preceding claims 1 through 10, characterized in that the first film is configured as i) a fluoropolymer film, preferably corona-treated, preferably with a thickness of at most 100 pm, or ii) a transparent polymer film (12), in particular polyester (preferably PET), carrying an optical isolation coating.

12. The method for manufacturing an illuminable laminated glass roof (1) according to any one of the preceding claims 1 through 11 , characterized in that the first thermoplastic interlayer sheet (5) has a thickness of at least 0.3 mm.

13. The method for manufacturing an illuminable laminated glass roof (1) according to any one of the preceding claims 1 through 12, characterized in that the second thermoplastic interlayer sheet (6) has a thickness of at least 20 pm.

14. The method for manufacturing an illuminable laminated glass roof (1) according to any one of the preceding claims 1 through 13, characterized in that the transparent polymer film, referred to as first film of the optical isolation layer (11), has a thickness of at least 20 pm and at most 200 pm.

15. An illuminable laminated glass roof (1) for a vehicle obtainable by the method according to any one of the preceding claims 1 through 14.

16. Functional laminate (23), including a laminated bilayer (15), in particular for use in the method according to any one of the preceding claims 1 through 14, comprising: one of a first thermoplastic interlayer sheet (5) and a second thermoplastic interlayer sheet (6), referred to as the thermoplastic reference interlayer sheet, the first thermoplastic interlayer sheet (5) preferably having a thickness of at least 0.3 mm and the second thermoplastic interlayer sheet (6) preferably having a thickness of at least 20 pm, an optical isolation layer (11), which comprises or is supported by a transparent thermoplastic polymer film, referred to as the first film, preferably having a thickness of at least 20 pm and at most 200 pm.

17. Functional laminate (23) according to claim 16, characterized in that the first film is configured as i) a fluoropolymer film, preferably corona-treated, preferably with a thickness of at most 100 pm, ii) or a transparent polymer film (12), in particular polyester (preferably PET), carrying an optical isolation coating.

18. Functional laminate (23) according to any of claims 16 or 17, characterized in that it comprises at least one light redirection element (10), preferably having a thickness of at least 70 pm and at most 200 pm.

19. Roll (18) comprising the functional laminate (23) according to any one of claims 16 through 18, in wound strip form, preferably at least 600 mm wide and / or at most 300 mm long.

20. Method for manufacturing a functional laminate (23) according to any one of claims 16 through 18, comprising: continuous pulling of the optical isolation layer (11) in strip form, wherein the first film is a fluoropolymer film or a transparent polymer film (12) carrying an optical isolation coating, continuous pulling of one of a first thermoplastic interlayer sheet (5) in strip form and a second thermoplastic interlayer sheet (6) in strip form, referred to as the thermoplastic reference interlayer sheet, preheating of the thermoplastic reference interlayer sheet in strip form, forming the functional laminate (23) by calendering the preheated thermoplastic reference interlayer sheet and the first film,optionally, winding the functional laminate (23) onto a winding roll (18).

21. Method for manufacturing a functional laminate (23) according to claim 20, comprising applying of at least one light-extraction layer (10) to the thermoplastic reference interlayer sheet or to the optical isolation layer (11) in the form of a scattering coating preferably with a coverage rate of at most 30%.

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