Apparatus with illuminatable pane - Patent application

Abstract

The present invention relates to an apparatus (100) comprising: - an illuminatable pane (101) having a first major surface (102) and an opposite second major surface (103); - illumination means (5) for generating light (6), the illumination means (5) being configured such that at least a part of the light (6) generated by the illumination means (5) is incident on the first main surface (102) in such a way that it can pass through the illuminable pane (101) and can exit the illuminable pane (101) at a second main surface (103), - a reflective structure (8) arranged on the second main surface (103), the reflective structure (8) having a plurality of reflective surfaces (12) for reflection of the light (6), the reflective surfaces (12) being in the form of inclined surfaces coated with a reflective layer (11), the reflective surfaces (12) being configured so as to be able to reflect at least a portion of the light (6) leaving the second main surface (103) into the illuminable pane (101) at an angle such that total reflection of the reflected light (13-15) occurs within the illuminable pane (101).

Description

[Technical field]

[0001] The present invention relates to a device having an illuminatable pane, and methods for making and using the same. [Background technology]

[0002] Laminated composite panes are produced in large industrial quantities and in series, for example for windshields in automobiles. They have an outer pane, an inner pane, and a thermoplastic interlayer that connects the outer pane to the inner pane over the entire surface. Typical interlayers are films made of polyvinyl butyral, which, in addition to their adhesive properties, have high toughness and high acoustic damping. The interlayer prevents the laminated glass from crumbling when broken. The laminated pane only cracks and remains dimensionally stable. In addition to laminated panes, single panes are also used, which are tempered to improve their impact and crash resistance compared to ordinary flat glass. Such single panes are also commonly called "single pane safety glass" and are used, for example, as side or roof panes in automobiles.

[0003] Laminated panes with electrically switchable optical properties are known in the prior art. Such laminated panes generally comprise an electro-optical functional element, typically an active layer between two surface electrodes. The optical properties of the active layer can be changed by a voltage applied to the surface electrodes. Examples of this are electrochromic functional elements, known for example from US 20120026573 A1 and WO 2012 / 007334 A1. Other examples are SPD functional elements (SPD = suspended particle device), known for example from EP 0 876 608 A1 and WO 2011 / 033313 A1. The transmission of visible light through the electro-optical functional element may be controlled by the applied voltage, whereby such adjustment of the optical properties is related to the external light conditions, but does not allow for independent illumination of the composite pane.

[0004] Pane illumination is often desirable, such as in vehicle structures, where two-dimensional pane lighting, pane contour lighting, accent lighting, or function lighting can have a very attractive effect, and where function lighting is also necessary, as a result, to enable a user to control certain functions in the dark.

[0005] For decorative illumination of panes, such as backlighting of displays, it is known to couple light at the edge surfaces of the pane and to use the total internal reflection of the coupled light occurring at the optical boundary surfaces of the pane. In this way, the pane acts as a light guide for the coupled light. For example, WO 2007 / 077099 describes a composite pane in which light is coupled through a light guide into a polycarbonate layer at the edge surface, and the coupled light is totally internally reflected at the interfaces of the polycarbonate layer and scattered at dome-shaped scattering centers.

[0006] In practice, light coupling at the edge surface of a pane can be satisfactory, especially when the pane is illuminated homogeneously across its surface, since light can be efficiently coupled across the edge surface. However, in certain applications, such as panes that are glued into a pane frame, such as automobile roof panes, light cannot be coupled into the pane at the edge surface. Also, such panes typically have edge surfaces that are circularly ground ("C-ground"), which prevents efficient light coupling, since light coupling at the edge surface typically requires smooth or flat pane edges.

[0007] Another method of coupling light into the pane is described, for example, in US Patent Application Publication No. 2020 / 241189. Light may be coupled into the luminescent glazing, which comprises a pane and a light source. The light of the light source is incident into the pane through one of the main surfaces of the pane. A light deflection element is arranged on the other main surface of the pane opposite the light source. The light deflection element deflects the light emitted from the light source back into the pane, whereby the light is guided into the pane by total internal reflection. The light deflection element is, for example, a microprism film attached to the pane. Furthermore, the edges of the pane may be provided with a reflective coating to prevent loss of incident light through the edges of the pane.

[0008] US 2021 / 0132281 discloses a multicolor grating-coupled backlight for electronic displays, having a light guide plate configured to guide light, a light source, and a grating coupler configured to receive, diffract, split, and redirect the light of the light source into the light guide plate. The light source may be disposed on one major surface of the light guide plate, while the grating coupler is disposed on the other major surface of the light guide opposite the light source. The grating coupler preferably consists of ridges or grooves on or within the pane surface. Furthermore, the grating coupler may contain a grating material having a refractive index different from that of the pane. The grating material is, for example, filled into the grooves of the grating coupler.

[0009] US2015 / 0260994 discloses an optical device intended as part of a head mounted display, the optical device comprising a light guide, a light source, and a deflection unit having a holographic diffraction grating for directing the light of the light source into the light guide. Alternative illumination glazing is shown in WO2020 / 188078 and CN113940061. Summary of the Invention [Problem to be solved by the invention]

[0010] The invention is therefore based on the object of avoiding the above-mentioned drawbacks and of enabling planar homogeneous illumination in the case of panes in which lateral coupling of light at the end surfaces is not possible, or at least not possible in an efficient manner. The illuminated panes should be easy and cheap to manufacture in industrial series production. [Means for solving the problem]

[0011] These and further objects of the invention are solved according to the proposal of the invention by a device with an illuminatable pane as claimed in claim 1. Advantageous embodiments of the invention are evident from the dependent claims.

[0012] The present invention discloses a device with an illuminable pane, which is configured as a planar light guide and thus suitable for guiding light by total internal reflection within the pane. The pane is flat, for example the pane is a flat glass pane. The illuminable pane can be non-curved or curved. The two main surfaces of the pane are for example parallel.

[0013] If the pane is non-curved, it will have a non-curved plane as well. If the pane is curved, a local tangential non-curved plane may be constructed at each point of the two major surfaces of the pane.

[0014] The pane has a (circumferential) end surface that connects the two opposing main surfaces. The end surface is for example perpendicular to the two main surfaces, but can for example be rounded. The term "main surface" is used to clearly distinguish it from the circumferential end surface. Preferably, the illuminable pane is transparent. Preferably, the illuminable pane is suitable for and provides for planar homogeneous illumination.

[0015] In the device according to the invention, the illuminable pane functions as a planar light guide and is suitable for guiding light by total internal reflection of light coupled into the pane, whereby the two main faces or surfaces of the pane each form an optical interface with the surroundings (e.g. air or a thermoplastic material, such as polyvinyl butyral) where total optical internal reflection of light coupled into the pane can occur. Essential for functioning as an optical interface is a difference in the optical refractive index, related to the wavelength of the incident light, of the materials adjacent to the interface. Total internal reflection occurs when the angle of incidence of the light on the optical interface (measured relative to the normal direction of the interface) is large enough. In line with common usage of the term, "total internal reflection" refers to the reflection of light at an optical interface caused by a difference in the optical refractive index of the materials forming the optical interface. Total internal reflection is therefore not a reflection on a reflecting surface (mirror).

[0016] The device further comprises lighting means for generating light for illuminating the illuminable pane, the lighting means being configured such that light generated by the lighting means impinges on a first main surface of the illuminable pane. The lighting means is preferably arranged on the first main surface. The light generated by the lighting means preferably only impinges on the first main surface when it is coupled into the illuminable pane for the first time. In any case, the light generated by the lighting means is not coupled into the illuminable pane at an end surface of the illuminable pane, i.e. at a side end of the illuminable pane. Thus, the light generated by the lighting means is not coupled into the illuminable pane for the first time either at the second main surface.

[0017] Specifically, the light generated by the illumination means is coupled into the illuminable pane at the first major surface such that at least a portion of the light does not undergo total internal reflection within the pane, but passes through the illuminable pane and exits the illuminable pane at the second major surface. If the light generated by the illumination means strikes the first major surface in a divergent form (i.e. a beam cone), the center beam of the divergent beam cone is directed such that total internal reflection of the center beam does not occur within the illuminable pane, but the center beam passes through the illuminable pane and exits the illuminable pane at the second major surface. In this case, the center beam can be directed, for example, perpendicular to the first major surface. Similarly, it is also possible for the center beam to be directed at an angle other than 90° (i.e. obliquely) to the first major surface, as long as it is ensured that the center beam does not undergo total internal reflection at the illuminable pane when the light generated by the illumination means is coupled into the illuminable pane at the first major surface. When the light generated by the illumination means strikes the first main surface in collimated (directed) form, i.e. with a parallel beam path, the collimated light beam is directed such that no total internal reflection of the collimated light beam occurs within the illuminable pane, but the collimated light beam passes through the pane and leaves the illuminable pane at the second main surface. The collimated light beam can, for example, be directed perpendicular to the first main surface. Similarly, it is also possible for the collimated light beam to be directed at an angle different from 90° (i.e. obliquely) to the first main surface, as long as it is ensured that the collimated light beam does not undergo total internal reflection within the illuminable pane when the light generated by the illumination means is coupled into the illuminable pane at the first main surface.

[0018] The illumination means according to the invention may also include lenses, mirrors, reflectors or other light-conductive elements that serve to couple light into the illuminable pane at the first major surface. Particularly advantageously, the illumination means includes a collimator that is configured to direct the light generated by the illumination means in a collimated manner (i.e. in parallel beam paths) onto the first major surface.

[0019] The illumination means is configured such that at least a portion of the generated light, in particular all the generated light, is incident on the first major surface in such a way that it can pass through the illuminable pane and exit the illuminable pane at the second major surface. The light impinging on the first major surface of the illuminable pane may impinge on the first major surface at a right angle (perpendicular to the illuminable pane) and / or at an angle different to the right angle (oblique).

[0020] Advantageous lighting means include, for example, laser diodes, light emitting diodes (LEDs) or incandescent bulbs, and the invention encompasses any type of lighting means or specific application. The lighting means may be suitable for generating colored light or white light. In principle, the lighting means may also be designed to generate light in the ultraviolet or infrared range. Preferred light colors are, for example, red (due to its pronounced signal effect), green (due to the high sensitivity of the human eye to the green spectrum) and blue (due to its particularly aesthetic and low glare effect).

[0021] In the case of a movable pane, such as an openable roof pane of a motor vehicle, the lighting means is preferably connected to the illuminable pane and is also movably arranged, it being understood that the lighting means may also be installed independently of the illuminable pane and any panes connected thereto.

[0022] The device further comprises a reflective structure for reflecting light generated by the illumination means and leaving the illuminable pane at the second main surface after passing through the illuminable pane without prior total reflection within the illuminable pane. The reflective structure is arranged on the second main surface of the illuminable pane. Advantageously, the reflective structure has a thickness (dimension measured perpendicular to the illuminable pane) in the range of 5 μm to 2 mm, in particular 25 μm.

[0023] The reflective structure has a plurality of reflective surfaces, which are in the form of inclined surfaces coated with a reflective layer suitable for reflecting light, preferably light in the wavelength range of 400 nm to 800 nm. More precisely, the inclined surfaces are inclined with respect to the illuminable pane. This means that in the case of a non-curved pane, the inclined surfaces are inclined with respect to the plane of the pane. Otherwise, in the case of a curved pane, each of the inclined surfaces is inclined with respect to a local tangential plane that may be configured at each point of the second main surface adjacent to the inclined surface. Typically, the reflective surfaces have many different orientations with respect to the illuminable pane. Preferably, the reflective layer is an electrically conductive layer. The reflective layer is typically a layer of metallic material, such as silver (Ag) or aluminum (Al). The reflective layer is suitable for reflecting the light generated by the illumination means. Preferably, the reflective structure does not introduce strong diffraction to the reflected light. Therefore, the structure is preferably much larger than the longest wavelength of the light used in the system.

[0024] Preferably, the reflecting surfaces reflect the incident light by direct reflection thereon. In this way, the reflecting surfaces form smooth surfaces, on which a large part of the incident light, preferably at least 70%, particularly preferably at least 80%, more particularly preferably at least 90%, most particularly preferably at least 98%, is reflected and directed in a particular direction (direct reflection). This type of reflection is different from other types of reflection, for example reflection due to diffraction of light. The reflectance expresses the proportion of the total light that is reflected. It is given in % (relative to 100% irradiated light) or as a unitless numerical value between 0 and 1 (normalized relative to the irradiated light). In the context of the present invention, statements regarding the degree of reflection (or the percentage of reflection) with respect to light refer to the degree of reflection measured at an angle of incidence of 0° on the irradiable pane in the area of ​​the reflecting structure. The angle of incidence is measured relative to the surface normal at the illuminable first main surface. The reflectance or reflectance spectrum information refers to a reflectance measurement using a light source that emits uniformly in the considered spectral range, with a normalized light intensity taken as 100%.

[0025] According to an advantageous embodiment of the invention, the reflective surfaces have a diameter of 1 μm to 500 μm, preferably 10 μm to 100 μm, particularly preferably 20 μm to 35 μm. The diameter of the reflective surfaces may be uniform or may vary. The given value is the arithmetic mean of all diameters if the diameters of all reflective surfaces are not uniform. In a certain range, the light reflection is particularly high and uniform and there are no unwanted reflection effects, such as light diffraction.

[0026] The reflective structure is a planar (curved or non-curved) structure that provides a number of tilted reflective surfaces distributed across the area of ​​the reflective structure, the tilted reflective surfaces having a number of orientations relative to the illuminable pane.

[0027] As detailed above, at least a portion of the light generated by the illumination means is coupled into the illuminable pane at the first major surface such that it can pass through the illuminable pane (without total internal reflection at the optical interfaces of the pane) and then exit the illuminable pane at the second major surface. The reflective structure is configured such that at least a portion of the light that passes through the illuminable pane and exits the pane at the second major surface can be reflected back into the pane by the reflective surface. In this way, the light that exits the illuminable pane at the second major surface is coupled into the illuminable pane a second time.

[0028] Furthermore, the reflective structure is configured such that at least a portion of the light leaving the illuminable pane at the second major surface is reflected back into the illuminable pane at an angle such that total internal reflection occurs within the illuminable pane at the optical interfaces of the illuminable pane (i.e., at the first major surface and the second major surface). Thus, at least a portion of the light is coupled into the illuminable pane at one side of the illuminable pane, passes through the illuminable pane without total internal reflection, and is then reflected back into the illuminable pane by the reflective structure at the other side of the illuminable pane such that at least a portion of the light reflected back into the pane by the reflective structure subsequently undergoes total internal reflection within the illuminable pane, i.e., is reflected back into the illuminable pane in a manner such that the angular condition for total internal reflection within the illuminable pane is satisfied. Many orientations of the reflective surfaces relative to the illuminable pane may result in at least a large percentage of the light incident on the first major surface being reflected back into the illuminable pane at the second major surface satisfying the angular condition for total internal reflection.

[0029] The device according to the invention therefore advantageously allows the use of an illuminable pane as a planar (curved or non-curved) light guide, where light is coupled into the pane by the reflecting structure (reflected back) in such a way that the angular condition for total internal reflection in the pane is met for the light reflected back into the pane. If the light generated by the illumination means is incident divergently on the first main surface, most of the generated light will pass through the pane without undergoing total internal reflection and can be reflected back into the pane by the reflecting structure at an angle such that it undergoes total internal reflection at the optical interfaces of the pane. Thus, at least a part of the light incident on the reflecting structure can be reflected back into the pane due to total internal reflection. This is even more true if collimated light of the illumination means hits the first main surface of the pane. In this way, the illuminable pane acts as a light guide and can be illuminated in a particularly planar homogeneous manner. Particularly advantageously, light can be coupled into the pane at one of the two main surfaces, whereby no coupling at the end surfaces of the pane is necessary. These are great advantages of the device according to the invention.

[0030] The decoupling of the light guided into the illuminable pane from the illuminable pane can be achieved by scattering the light, for example in the region of the main surfaces. For example, one or both main surfaces may be provided with one or more scattering structures, respectively, at which scattering of the light totally reflected in the pane occurs, whereby the light can be scattered from the pane. In principle, the scattering structures are configured such that at the scattering structures the condition of total internal reflection no longer applies. For this purpose, one or both main surfaces of the pane may be provided with, for example, a local roughening acting as a scattering structure. Such scattering structures may be provided as desired at the first and / or second main surface. The skilled person is familiar with the means for decoupling the totally reflected light from the light guide (see, for example, WO 2007 / 077099), so that it is not necessary to explain them in more detail here.

[0031] Particularly preferably, the light generated by the lighting means is collimated by the collimator and impinges in collimated (directed) form on the first major surface, whereby a particularly high proportion of the generated light can be reflected back into the pane by the reflective structure (after passing through the pane without total internal reflection) and then undergoes total internal reflection within the pane.

[0032] According to an advantageous embodiment of the device according to the invention, the reflecting structure is arranged on the opposite side of the lighting means, seen vertically through the illuminable pane, so that the lighting means is arranged on one side of the illuminable pane and the reflecting structure is arranged on the other side of the illuminable pane, which allows a particularly simple practical implementation of the device according to the invention.

[0033] According to an advantageous embodiment of the device according to the invention, the reflecting structure is formed by a reflector, which is different from the illuminable pane. The reflector may therefore be individualized for the illuminable pane and can be provided in an assembled manner. In this way, the reflector is not partly formed by the illuminable pane (see below). The reflecting structure configured as a reflector is arranged on the second main surface and is preferably attached to the illuminable pane, for example by bonding. This measure allows a particularly simple design of the reflecting structure. The reflector does not necessarily have to be rigidly connected to the pane by a connection means (for example bonding). Instead, it can be envisaged that the reflector is not rigidly connected to the pane by a connection means, for example if the reflector is laminated in a composite pane (see below).

[0034] Preferably, the reflective structure configured as a reflector is in the form of a microprism film provided with a reflective layer suitable for reflecting light, which is bonded, for example, to the second main surface of the pane. Such microprism films are commercially available and are also known to the skilled person under the term "reflective film". Such microprism films have microscopic bodies, so-called microprisms, which serve to direct the light. The microprisms provide the inclined surface of the reflective structure. The surface of the microprism film is then coated with a reflective layer suitable for reflecting light, which may be done by a common coating process, whereby the microprisms are provided with a reflective layer on their surface. The microprism film coated with the reflective layer does not necessarily have to be firmly connected to the pane by a bonding agent (for example by bonding). Rather, it may not be firmly connected to the pane by a connecting means, for example when it is laminated in a composite pane (see below).

[0035] The reflective structure configured as a reflector is preferably arranged directly on the second main surface of the illuminable pane, the reflector and the pane may for example be in direct contact, optionally only separated by fastening means for fastening the reflective structure to the pane (for example adhesive bonding). Preferably, the microprisms are located between the reflective layer and the illuminable pane.

[0036] According to an alternative embodiment of the device according to the invention, the inclined surface of the reflective structure at the second main surface is formed by the illuminable pane itself, i.e. the inclined surface is formed by the pane in the area of ​​the reflective structure on the second main surface. To obtain the reflective structure, the inclined surface is coated with a reflective layer suitable for the reflection of light, which can be done by common coating methods. Preferably, the reflective structure is further inclined with respect to the illuminable pane. "With respect to the illuminable pane" in this context means that the reflective structure is formed such that it is inclined with respect to the general orientation of the plane of the illuminable pane. If the pane is not curved, the pane has a plane that is likewise not curved. If the pane is curved, a local tangential non-curved surface may be constituted at each point of the two main surfaces of the pane. For the purpose of determining the orientation of the plane, the contribution of the reflective structure can be neglected.

[0037] According to an embodiment of the device according to the invention, the planar (curved or non-curved) reflective structure is inclined with respect to the illuminable pane, i.e. the plane of the reflective structure is inclined with respect to the plane of the illuminable pane. As a result, the distance between the inclined reflective surface and the second main surface is increased along at least one direction, whereby light reflected from the reflective surface and having a directional component in at least one direction may not be shadowed by an adjacent reflective surface. Advantageously, the proportion of light that can be reflected into the illuminable pane and then totally reflected therein may be increased.

[0038] According to an advantageous embodiment of the device according to the invention, the reflecting structure consists of a material whose optical refractive index is equal or at least approximately equal to the optical refractive index of the material of the illuminable pane. This measure advantageously allows optical refraction in the reflecting structure to be avoided, or at least to a large extent avoided, when the light generated by the illumination means passes into the reflecting structure at the second main surface of the pane, so that reflection occurs only in the reflecting layer of the reflecting structure. In particular, total reflection at the optical interface between the illuminated pane and the reflecting structure configured as reflector (optical transition: pane - reflecting structure), due to differences in refractive index, can be avoided.

[0039] According to an advantageous embodiment of the device according to the invention, the illuminable pane is a glass pane.

[0040] The illuminable pane may, for example, be configured as a single pane that is not connected to further panes and may in particular be configured as toughened safety glass that is provided with particularly high impact strength and shatter resistance by tempering.

[0041] The illuminable pane can also be a part of a laminated pane. The laminated pane has an outer pane and an inner pane, which are joined together by lamination through an intermediate layer. The terms outer pane and inner pane are only used to distinguish the first pane from the second pane. When the composite pane is used as a vehicle pane or architectural pane, the outer pane preferably faces the outer space of the composite pane, and the inner pane faces the inner space, but this is not necessarily the case.

[0042] Preferably, the illuminable pane is the inner or outer pane of a composite pane, particularly preferably the inner pane of a composite pane, in which case it is preferred that the outer pane is colored, in particular opaque, and / or that the intermediate layer is colored, in particular opaque, which allows the design of very attractive composite panes, in which the inner pane is subjected to a particularly homogeneous planar illumination.

[0043] It is also possible and preferred that the illuminable pane is laminated between the inner and outer panes in a composite pane. During production, the illuminable pane is preferably sandwiched between two sheets of thermoplastic material (for example PVB sheets). In this case, it is preferred that the outer pane is colored and / or that the thermoplastic film that is arranged relatively close to the outer pane is colored, in particular opaque. The intermediate layer is therefore preferably partially colored, in particular opaque. This allows the design of very attractive composite panes, in which the inner pane receives a particularly homogeneous planar illumination.

[0044] The panes of the illuminable pane and / or composite pane are preferably made of glass, particularly preferably soda-lime glass, as is common for window panes. However, the panes may also be made of other types of glass, such as quartz glass, borosilicate glass or aluminosilicate glass, or of hard clear plastics, such as polycarbonate, polyethylene terephthalate (PET) or polymethyl methacrylate. The panes may be made of untempered glass, partially tempered glass or tempered glass. The thickness of the panes may vary widely and can be adapted to the requirements of the individual case. Preferably, the thickness of the panes is between 0.1 mm and 10 mm, in the case of glass it is preferably between 1 mm and 5 mm, most preferably between 1.4 mm and 3 mm.

[0045] Illuminatable panes made of a polymeric material, such as polyethylene terephthalate (PET), may for example be flexible and may have a low thickness, such as 0.2 mm or less. Such illuminatable panes are preferably laminated within a composite pane.

[0046] The illuminable pane and / or the panes of the composite pane may generally be clear and colorless, but may also be tinted, frosted, or tinted.

[0047] The intermediate layer is formed by at least one thermoplastic intermediate layer film. The thermoplastic intermediate layer film comprises at least one thermoplastic polymer, preferably ethylene vinyl acetate (EVA), polyvinyl butyral (PVB) or polyurethane (PU), or a mixture or copolymer or derivative thereof. The thickness of the intermediate layer, in particular the thickness of the thermoplastic bonding film, is preferably 0.2 mm to 2 mm, particularly preferably 0.3 mm to 1 mm, for example 0.38 mm or 0.76 mm.

[0048] According to an advantageous embodiment of the device according to the invention, the lighting means are arranged in an overlapping relationship with the black printing applied to the outer or inner sheet, when viewed vertically through the composite pane, which makes it possible to conceal the lighting means in an advantageous manner, whereby the composite pane as a whole can be designed in a very aesthetically pleasing manner.

[0049] According to an advantageous embodiment of the device according to the invention, an electrical functional layer, in particular an IR-reflective layer (reflective coating for the infrared range), or an electrical functional element is provided within the composite pane.

[0050] The electrical functional layer may be applied to the surface of the outer pane or to the surface of the inner pane, preferably on the surface facing the intermediate layer, thereby protecting the coating from corrosion and mechanical action. Alternatively, the coating may be incorporated into the composite pane in the form of a coated thermoplastic film, such as a coated polyethylene terephthalate (PET). In this case, the coated film is preferably disposed between the first and second thermoplastic interconnect films.

[0051] The infrared reflective coating typically has at least one electrically conductive layer. The coating may further have a dielectric layer, which serves, for example, to adjust the sheet resistance, to protect against corrosion, or to reduce reflection. The electrically conductive layer preferably contains silver or an electrically conductive oxide (transparent conductive oxide, TCO), such as indium tin oxide (ITO). The electrically conductive layer preferably has a thickness of 10 nm to 200 nm. To improve conductivity while maintaining high transparency, the coating may have multiple electrically conductive layers separated by at least one dielectric layer. For example, the electrically conductive coating may contain two, three, or four electrically conductive layers.

[0052] Typical dielectric layers include oxides or nitrides such as silicon nitride, silicon oxide, aluminum nitride, aluminum oxide, zinc oxide, or titanium oxide, etc. It will be appreciated that the electrically conductive coating may also serve to electrically heat the pane.

[0053] In a device according to the invention, the combination of a reflective structure with an IR-reflective layer can be particularly advantageous because this can allow a certain amount of light to be reflected back into the illuminatable pane by total internal reflection and therefore the light generated by the lighting means does not have to be collimated as much, thereby achieving the same effect as without the IR-reflective layer.

[0054] The functional layer may be an electrically heatable layer, thereby providing the laminated pane with a heating function. Such heatable layers are known per se to the person skilled in the art. They typically contain one or more, for example two, three or four, electrically conductive layers. These layers preferably contain or consist of at least one metal, for example silver, gold, copper, nickel and / or chromium, or a metal alloy, preferably containing at least 90% by weight of metal, in particular at least 99.9% by weight of metal. Such layers exhibit particularly advantageous electrical conductivity and at the same time a high transmittance in the visible spectral range. The thickness of a single layer is preferably 5 nm to 50 nm, particularly preferably 8 nm to 25 nm. At such a thickness, advantageously high transmittance in the visible spectral range and particularly advantageous electrical conductivity are achieved.

[0055] The electrical functional layer is preferably arranged on the surface of at least one pane, partially covering or covering the pane surface, but preferably over a large area. The term "over a large area" means that at least 50%, at least 60%, at least 70%, at least 75% or preferably at least 90% of the pane surface is covered by the functional layer. However, the functional layer may also extend over a relatively small part of the pane surface. The electrical functional layer is preferably transparent to visible light. In an advantageous embodiment, the functional layer is a single layer or a layer structure consisting of several individual layers, with a total thickness of less than or equal to 2 μm, particularly preferably less than or equal to 1 μm.

[0056] The electrically functional element can be an electro-optical component, such as an SPD or PDLC element, as explained at the beginning. Electro-optical components, such as an SPD or PDLC element, are commercially available as multilayer foils, in which the active layer is arranged between two surface electrodes, which are used to apply a voltage to control the active layer. Typically, the two surface electrodes are arranged between two carrier films, typically made of PET.

[0057] Moreover, commercially available multilayer films are covered on both sides with a protective film made of polypropylene or polyethylene, which also serves to protect the carrier film from dirt or scratches. When producing a laminated pane, the electro-optical components are cut out of the multilayer film to the desired size and shape and inserted between the interlayer films, whereby two glass panes are laminated together to form a laminated pane. A typical application is a windshield with an electrically adjustable sun visor, which are known for example from DE 102013001334 A1, DE 102005049081 A1, DE 102005007427 A1 and DE 102007027296 A1.

[0058] For the purposes of the present invention, "transparent" means a transmittance for visible light of at least 70%, in particular at least 75%. "Opaque" therefore means a light transmittance of less than 15%, preferably less than 5%, in particular 0%.

[0059] The laminated panes are made by lamination using conventional methods known per se to those skilled in the art, such as, for example, an autoclave process, a vacuum bag process, a vacuum ring process, a calendar process, a vacuum laminator, or a combination thereof. The bonding of the outer and inner panes, and optionally additional illuminable panes, is usually carried out under the action of heat, vacuum, and / or pressure.

[0060] The invention further extends to a method for manufacturing a device having an illuminable pane according to the invention as described above. The method according to the invention comprises at least the following steps: (a) providing an illuminatable pane having a first major surface and an opposing second major surface; (b) disposing an illumination means for generating light at the first major surface, whereby light generated by the illumination means is incident on the first major surface in a manner that it can pass through the illuminable pane and exit the illuminable pane at the second major surface; (c) providing a reflective structure on the second major surface comprising a reflective surface, the reflective surface in the form of an inclined surface that is inclined relative to the illuminable pane and is coated with a reflective layer, the reflective surface being configured to be able to reflect light generated by the illumination means into the illuminable pane at an angle such that total reflection of the reflected light occurs within the illuminable pane.

[0061] Furthermore, the invention extends to the use of a device according to the invention having an illuminable pane in land, air or water transport, in particular in trains, ships and vehicles, for example as a windshield, rear window, side window and / or roof window, in buildings, in particular in access areas, window areas, roof areas or facade areas, as a part to be integrated into fixtures and appliances.

[0062] The various embodiments of the invention may be realized individually or in any combination. In particular, the features mentioned above and below may be used not only in the combinations shown, but also in other combinations or alone, without departing from the scope of the invention.

[0063] The invention will now be explained in more detail by means of exemplary embodiments with reference to the attached figures, in which identical or identically acting elements are provided with the same reference symbols and are shown in a simplified, not to scale representation: [Brief description of the drawings]

[0064] [Figure 1] FIG. 1 is a cross-sectional view of an exemplary embodiment of a device according to the present invention having an illuminatable pane within a composite pane. [Diagram 2] FIG. 2a is an enlarged cross-sectional view of the device of FIG. [Diagram 3] FIG. 2b is a modified version of the device of FIG. 2a. [Figure 4] FIG. 3 is a further embodiment of a device according to the invention having an illuminatable pane within a composite pane. [Diagram 5] FIG. 4 is a further embodiment of a device according to the invention having an illuminatable pane within a composite pane. [Figure 6] FIG. 5 is a further embodiment of a device according to the invention having an illuminable pane within a composite pane. [Figure 7] FIG. 6 is a further embodiment of a device according to the invention having an illuminatable pane within a composite pane. [Figure 8] FIG. 7 is a further embodiment of a device according to the invention having an illuminatable pane within a composite pane. [Figure 9] FIG. 8 is a flow chart of a process according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] Figures 1 and 2a show an embodiment of a device according to the invention, generally designated by the reference number 100. The cross-sectional view corresponds to a section taken vertically through the pane.

[0066] The device 100 comprises a composite pane 1 having an outer pane 2 and an inner pane 3, which are connected to each other by a thermoplastic intermediate layer 4. The different faces of the outer pane 2 and inner pane 3 are designated by Roman numerals in the conventional notation.

[0067] Here, the surface of the outer pane 2 facing the outer environment is referred to as side I, the surface of the outer pane 2 facing the intermediate layer 4 is referred to as side II, the surface of the inner pane 3 facing the intermediate layer 4 is referred to as side III, and the surface of the inner pane 3 facing the inner environment is referred to as side IV.

[0068] In the embodiment of the device 100 shown in Fig. 1, the inner pane 3 of the laminated pane 1 serves as an illuminable pane 101 having a first main surface 102 (side IV) and an opposite second main surface 103 (side III). The two main surfaces 102, 103 are connected to each other by a front end surface 104. The term "main surface" is used to distinguish it from the end surface 104. In the exemplary embodiment of Fig. 1, the inner pane 3 is designed as an illuminable pane 101 in the sense of the present invention. To highlight this feature, the inner pane 3 is further provided with a reference number that refers to the illuminable pane 101.

[0069] Adjacent to or at the first main surface 102, lighting means 5 are arranged, which may generate light 6 that is collimated by a collimator 7 and impinges in a (directed) form on the first main surface 102 (side IV) of the illuminable pane 101 (i.e. the inner pane 3). The light 6 coupled into the illuminable pane 101 at the first main surface 102 passes through the illuminable pane 101 and exits it at the second main surface 103 (side III) without prior total internal reflection within the illuminable pane 101.

[0070] A reflecting structure 8 is located on the second main surface 103 of the illuminable pane 101, which is here formed, for example, in the form of a prefabricated reflector different from the illuminable pane 101. The reflecting structure 8 here comprises, for example, a microprism foil 9 (shown in FIG. 2a), which comprises a foil-like carrier, not shown in more detail, on which microprisms 10, for example glass bodies, are formed, which are shown here diagrammatically and even as triangles. The microprisms 10 essentially provide a number of inclined surfaces, which are arranged obliquely or non-parallel to the plane of the composite pane 1 and of the illuminable pane 101. As previously detailed, this may be understood as being inclined with respect to the plane of the illuminable pane 101, if the illuminable pane 101 is not curved, or as being inclined with respect to a local tangential plane that may be constituted at each point of the second main surface 102 adjacent to the inclined surface. Typically, the microprisms 10 have a reflecting surface with many different orientations with respect to the illuminable pane 101. The microprism film 9 is coated with a metallic reflective layer 11, such as silver or aluminum, suitable for reflecting light 6. In this way, the inclined surface becomes a reflective surface 12 for the incident light 6. The reflective layer 11 is located on the side of the microprisms 10 facing away from the illuminable pane 101.

[0071] The reflecting structure 8 is arranged such that the light 6 generated by the illumination means 5 is coupled into the illuminable pane 101 at a first main surface 102 and leaves the illuminable pane 101 at a second main surface 103 (without prior total internal reflection within the illuminable pane 101) impinges on the reflecting structure 8, i.e. on the reflecting surface 12, where the light 6 passes through microprisms 10. In this embodiment, the reflecting structure 8 is arranged opposite the illumination means 5, as viewed in a vertical direction through the composite pane 1 at the location of the reflecting structure 8.

[0072] At least a portion of the light 6 incident on the reflective surface 12 is reflected by the reflective surface 12 back into the illuminable pane 101 as a first reflected ray 13, i.e., coupled into the illuminable pane 101 a second time. Due to the oblique position of the reflective surface 12, the first reflected ray 13 is reflected into the illuminable pane 101 at an angle such that total internal reflection occurs within the illuminable pane 101. This is shown in Figure 1, where the first reflected ray 13 is totally internally reflected at an optical interface (e.g., glass-air) present at the first major surface 102 (side IV) to become a second reflected ray 14. The second reflected ray 14 may then be totally internally reflected at an optical interface (e.g., glass-PVB) present at the second major surface 103 (side III) to become a third reflected ray 15, and so on. By scattering, the reflected light may leave the illuminable pane 101, whereby local scattering structures (e.g. roughening of the first main surface 102 and / or the second main surface 103) may be provided for this purpose, which will not be described in more detail here. Essential to the invention is the coupling of the light 6 into the illuminable pane 101 at the first main surface 102 and the total internal reflection of the light 6 within the illuminable pane 101, thereby allowing a preferably homogeneous illumination of the illuminable pane 101. Thus, coupling of the light 6 into the illuminable pane 101 at the edge surface 104 is neither necessary nor intended.

[0073] In Fig. 1, the angle theta (θ) of the second reflected light 14 with respect to the normal through the composite pane 1 or illuminable pane 101 is illustrated as an example. This angle is such that total reflection of the second reflected light 14 occurs at the optical interface formed at the second major surface 103. It will be understood that the reflective surface 12 may employ multiple orientations whereby at least a portion of the light 6 may be reflected such that total internal reflection occurs within the illuminable pane 101. For example, when a pane 101 made of soda-lime glass and an interlayer 4 made of polyvinyl butyral (PVB) are used, the angle theta (θ) is about 78°.

[0074] The outer pane 2 is transparent or tinted, preferably tinted. The intermediate layer 4 is transparent or opaque, preferably tinted with a light transmission of more than 50%, so that the composite pane 1 with the illuminable inner pane 3 has a particularly attractive appearance.

[0075] Figure 2a shows an enlarged cross-section of the composite pane 1 of Figure 1. As explained above, the microprisms 10 are shown diagrammatically as triangular in cross-section, and the shape of the microprisms 10 may be regular or irregular. What is important is that the microprisms 10 provide many angled surfaces with different orientations, which results in total internal reflection of the reflected light within the illuminable pane 101.

[0076] With reference to FIG. 2b, a modification of the device of FIG. 1 and FIG. 2a is described. To avoid unnecessary repetition, only the differences are described. In FIG. 2b, the dimension d1 of the microprism 10, whose cross section is shown diagrammatically as a triangle, is depicted. The dimension d1 is intended to illustrate that the first reflected light 13 is not shadowed by the adjacent microprism 10 if the dimension d1 does not exceed a certain threshold value. As shown by FIG. 2b, the dimension d1 can advantageously be increased to a dimension d2 (d2>d1) if the microprism foil 9 is set obliquely with respect to the plane of the illuminable pane 101. In FIG. 2b, the flat microprism foil 9 is inclined with respect to the illuminable pane 101, whereby the end region of the microprism foil 9 (here, for example, relatively to the right) is at a greater distance from the illuminable pane 101 than the end region of the microprism foil 9 (here, for example, relatively to the left). It is understood that this applies only to microprisms 10 located in a direction with a greater distance from the illuminable pane 101. As a result, the proportion of light that can be reflected into the pane 101 satisfying the condition for total internal reflection may be advantageously increased.

[0077] In figure 3 an embodiment of the device 100 as described with reference to figures 1 and 2a is shown in a perspective view. The device 100 thus comprises an illumination means 5 with an associated collimator 7 for collimating the light 6 produced by the illumination means. The illumination means 5 with the collimator 7 is attached to a first main surface 102 (side surface IV) of an illuminable pane 101.

[0078] Figure 4 shows in a perspective view a further embodiment of the device 100 as described with reference to figures 1 and 2a. The device 100 thus comprises a plurality of lighting means 5 arranged in a row, each having an associated collimator 7. The lighting means 5 with their associated collimators 7 are attached to a first main surface 102 (side surface IV) of an illuminable pane 101. By means of the plurality of lighting means 5, the illuminable pane 101 can be illuminated relatively strongly and / or in a relatively good planar homogeneous manner.

[0079] Figure 5 shows in a perspective view a further embodiment of the device 100 as described with reference to figures 1 and 2a or 2b. The device 100 thus comprises a plurality of lighting means 5 associated with a common collimator 7 arranged in a row. The lighting means 5 with their associated collimators 7 are attached to a first main surface 102 (side surface IV) of an illuminable pane 101.

[0080] FIG. 6 shows a further embodiment of the device 100, which comprises a composite pane 1 with an outer pane 2 and an inner pane 3, connected to each other by an intermediate layer 4, and a lighting means 5. To avoid unnecessary repetition, only the differences from the embodiment of FIG. 1 are described. Thus, the composite pane 1 comprises, in addition to the inner and outer panes 2, 3, an illuminable pane 101, which is formed as a further pane. The illuminable pane 101 is located inside the intermediate layer 4 and is sandwiched between two lamination films 4a, 4b made of a thermoplastic material (for example PVB) during lamination. The lamination film 4b, which is located relatively closer to the inner pane 3, is transparent, while the lamination film 4a, which is located relatively further from the inner pane 3, has a light transmission preferably greater than 50%. This is shown by hatching in FIG. 6. The outer pane 2 is transparent or colored, preferably colored. In the embodiment of FIG. 6, the reflective structure 8, as shown in FIG. 1 and FIG. 2a, is formed as a separate reflector arranged on the second main surface 103.

[0081] In Fig. 7 an alternative is illustrated. Thus, in a device similar to Fig. 6, the inclined surface of the reflective structure 8 is formed by an illuminable pane 101 at its second main surface 103. A correspondingly formed area of ​​the illuminable pane 101 is then part of the reflective structure 8. The inclined surface is coated with a reflective layer 11.

[0082] In the illustrated embodiment, the composite pane 1 may be provided with an opaque coating (not shown), e.g. a black printing, on one of the sides I-IV, and the lighting means 5 are arranged in an overlapping manner in a direct view through the composite pane 1, whereby the lighting means 5 are hidden by the opaque coating. Furthermore, the composite pane 1 may have a functional layer (not shown), in particular an IR layer, preferably on side II.

[0083] Figure 8 illustrates by means of a flow chart the process according to the invention. Steps (a), (b) and (c) involve: (a) providing an illuminatable pane having a first major surface and an opposing second major surface; (b) disposing an illumination means for generating light at the first major surface, whereby light generated by the illumination means is incident on the first major surface in a manner that it can pass through the illuminable pane and exit the illuminable pane at the second major surface; (c) providing a reflective structure on the second major surface comprising a reflective surface, the reflective surface being in the form of an inclined surface that is inclined relative to the illuminable pane and is coated with a reflective layer, the reflective surface being configured such that it can reflect light generated by the lighting means into the illuminable pane at an angle such that total reflection of the reflected light occurs within the illuminable pane.

[0084] As can be seen from the above description, the present invention discloses a novel device with an illuminable pane, where light is coupled into the illuminable pane at one side of the illuminable pane and reflected back into the illuminable pane at the other side of the illuminable pane by a reflecting structure, whereby at least a portion of the reflected light undergoes total internal reflection within the illuminable pane. This eliminates the need to couple light at the edge surface of the illuminable pane into the pane, so that the illuminable pane can be illuminated even when the edge surface is not accessible by the installation of the pane (for example, by installing it in the body frame of a car). Furthermore, the edge surface does not have to be flat or even uniform, but in particular can have a circular grind (C grind). [Explanation of symbols]

[0085] 1. Composite pane 2 Outer Pane 3 Inner Pane 4. Middle Tier 4a, 4b Laminated film 5 light source 6 light 7 Collimator 8 Reflective structure 9 Micro Prism Foil 10 Microprism 11 Reflective layer 12 reflective surfaces 13 First Reflection 14 Second Reflection 15 The Third Reflection 100 devices 101 Illuminated pane 102 first main surface 103 Second main surface 104 End surface

Claims

1. An apparatus (100) comprising: an illuminable pane (101) having a first major surface (102) and an opposite second major surface (103); - illumination means (5) for generating light (6), said illumination means (5) being configured such that at least a part of said light (6) generated by said illumination means (5) is incident on said first main surface (102) in such a way that it can pass through said illuminable pane (101) and can exit said illuminable pane (101) at said second main surface (103); a reflecting structure (8) arranged on said second main surface (103), comprising a plurality of reflecting surfaces (12) for reflection of light (6), said reflecting surfaces (12) being in the form of inclined surfaces coated with a reflecting layer (11), said reflecting surfaces (12) being configured so as to be able to reflect at least a portion of said light (6) leaving said second main surface (103) into said illuminable pane (101) at an angle such that total reflection of the reflected light (13-15) occurs within said illuminable pane (101); An apparatus (100) having:

2. 2. The device (100) according to claim 1, wherein the reflective structure (8) is arranged facing the lighting means (5) when viewed perpendicularly through the illuminable pane (101).

3. 3. The device (100) according to claim 1 or 2, wherein the reflecting structure (8) is made of a material with an optical refractive index equal to the optical refractive index of a material of the illuminable pane (101).

4. The apparatus (100) according to any one of claims 1 to 3, wherein the illumination means (5) comprises a collimator (7) configured such that light (6) generated by the illumination means (5) impinges on the first main surface (102) in a collimated manner.

5. The device (100) according to any one of the preceding claims, wherein the reflecting structure (8) comprises a reflector arranged on the second main surface (103).

6. 6. The device (100) according to claim 5, wherein the reflector comprises a microprism film (9) coated with the reflective layer (11), which is in particular bonded to a second pane surface (103).

7. The device (100) according to any one of the preceding claims, wherein the inclined surface of the reflective structure (8) is formed by the illuminable pane (101).

8. The device (100) according to any one of the preceding claims, wherein the reflective structure is inclined with respect to the illuminable pane (101).

9. Device (100) according to any one of the preceding claims, wherein the illuminable pane (101) is a single pane not connected to further panes, in particular a single pane of safety glass.

10. The device (100) according to any one of claims 1 to 8, wherein the illuminatable pane (101) is part of a laminated composite pane (1), the composite pane (1) having an outer pane (2) and an inner pane (3) connected to each other via an intermediate layer (4).

11. The device (100) according to claim 10, wherein the illuminatable pane (101) is the inner or outer pane (2, 3) of the composite pane (1), in particular the inner pane (3) of the composite pane (1), or is laminated between the inner pane (2) and the outer pane (3).

12. 12. The device (100) according to claim 10 or 11, wherein the inner or outer pane (2, 3), in particular the outer pane (2), is a tinted pane and / or the intermediate layer (4) is a tinted intermediate layer that is at least partially tinted and / or the lighting means (5) is arranged so as to overlap a black printing arranged on the outer or inner pane (2, 3) when viewed vertically through the composite pane (1).

13. Device (100) according to any one of claims 10 to 12, wherein the composite pane (1) comprises a functional layer, in particular an IR-reflective layer.

14. A method for manufacturing a device (100) comprising an illuminable pane (101) according to any one of claims 1 to 13, comprising the steps of: (a) providing an illuminatable pane (101) having a first major surface (102) and an opposing second major surface (103); (b) arranging lighting means (5) for generating light on said first main surface (102), whereby light (6) generated by said lighting means (5) is incident on said first main surface (102) in such a manner that it can pass through said illuminable pane (101) and exit said illuminable pane (101) at said second main surface (103); (c) providing said second main surface (103) with a reflective structure (8) comprising a reflective surface (12), said reflective surface (12) being in the form of an inclined surface inclined with respect to said illuminable pane (101) and coated with a reflective layer (11), said reflective surface (12) being configured such that it is able to reflect the light (6) generated by said illumination means (5) into said illuminable pane (101) at an angle such that total internal reflection of reflected light (13-15) occurs within said illuminable pane (101); A manufacturing method comprising:

15. Use of a device (100) comprising an illuminable pane (101) according to any one of claims 1 to 14 in land, air or water transport, in particular in trains, ships and automobiles, for example as a windscreen, rear window, side window and / or roof window, in buildings, in particular in access areas, window areas, roof areas or facade rears, as components integrated into fixtures and appliances.

Images