Lighting vehicle glazing

Abstract

The present invention relates to a lighting vehicle glazing (1) comprising an external glass pane (11) having an outer surface (P1) and an inner surface (P2) and an internal glass pane (12) having an inner surface (P3) and an outer surface (P4), acting as a light guide layer, and the external and the internal glass panes (11, 12) being laminated together via at least a plastic interlayer (13), a light source (21) provided in the vicinity of the outer surface (P4) of the internal glass pane (12), at least one coupling element (22) provided in the vicinity of the light source (21), and optically bonded to the internal glass pane (12) on its outer surface (P4), that couples the light emitted from the light source (21) into the internal glass pane (12), the coupling element (22) having a short edge (221), a long edge (222) opposite to the short edge (221) and a tapered edge (223) connecting the short (221) and long edges (222).

Description

LIGHTING VEHICLE GLAZINGFIELD OF THE INVENTION

[0001] The present invention relates to a lighting glazing unit for vehicles, particularly a lighting glazing forming part of the roof of a vehicle. More particularly a light source provided therein illuminates the vehicle laminated glazing. Such a vehicle window is known from practice and can be used in particular in the field of a vehicle roof.BACKGROUND OF THE INVENTION

[0002] It is known from prior art that in lighting vehicle glazings, the glass pane acts as a light guide layer. It is also known that the light from a glazed roof provided with a light source can be coupled to a light guide layer. For safety of passengers of the vehicle, the glazing is a laminated glazing provided with an external and an internal glass pane. It is well known that a coupling element is provided on an edge of the internal glass pane acting as a light guide layer. The internal glass pane is thus generally smaller than the outer glass pane in order to have sufficient space to fix the coupling element against the lateral edge of the internal glass pane. Thus, light emitted by the light source can be coupled through the edge of the light guide layer.

[0003] It is also known that the coupling element is provided onto the internal glass pane from the bottom so that the light is enabled to couple the internal glass pane. In such configuration, the lighting unit comprising the light source and the coupling element occupy a nonnegligible space under the internal glass pane and usage of such configuration limits the usable area of the glazing, i.e. , the available area that can be illuminated by the lighting unit.

[0004] It is also known that the coupling element can be various shapes and materials, one of the materials used for the coupling element is glass since the glass has the same refractive index as the internal glass pane so that the light passes through without loss or minimum loss. The coupling element is fixed onto the bottom of the internal glass pane by optically clear adhesives which also have similar refractive indices like glass.

[0005] It is also known from EP3463869, a lighting glazing comprising a glazing with holes and into which the light source is provided, although the coupling of light isimproved with the collimation optics, such configuration with holes in the glazing makes the glazing difficult to produce.

[0006] It is also known from WO2021198262 to use a plastic coupling on the outer face (P4) of the roof. The coupling element described in WO’262 has a trapezoidal shape. Plastic material is often used for coupling element because it is easy to shape in the required shape and more particularly in complex shape in order to play the role of light guide. However, the coefficient of thermal expansion and the refractive index of plastic is different from the coefficient of thermal expansion and refractive index of the glass leading to reduced reliability of the assembly and a loss of light emitted by the light source through the glazing. Another issue with the plastic coupling is that the aging of the plastic material is beyond / faster than the glass, this one may lead to a decrease in the brightness or a color shift and eventually the plastic coupling element needs to be replaced.

[0007] It is also known from WO2023198638 to use a glass coupling element provided with a base surface and a light coupling region opposite to the base surface, and the coupling element is optically connected to the internal glass pane via its base surface, a top LED light source positioned onto the light coupling region to transmit light into the coupling element. Although a glass coupling element is disclosed, some embodiments requires plastic coupling element, since such a glass coupling element cannot be manufactured.

[0008] Additionally, more coupling elements are proposed by W02022030544, WO20231 60942 and WO2023198479 that the coupling element is trapezoid or wedge shaped or having tapered edge.

[0009] It is also known from WO2024017968 that the coupling element being glass and produced from the same float glass as the glazing, moreover the coupling element is shaped as strips in order to fit better onto the curved glazing. Moreover, said patent application discloses how light coupled into the internal glass pane, defines the total internal reflection condition, light coupling efficiency, how the coupling element is optically fixed onto the internal glass pane. The present invention provides an improved version of the said patent application.

[0010] Although there are many solutions in the prior art, there is still a need for such a coupling element that maximizes the amount of light coupled to internal glass pane,i.e. , maximizes the coupling efficiency and yet maximizes the usable glazing area by occupying minimum space. Moreover, even those conditions satisfied, such a solution also needs to be less prone to alignment tolerances and provide ease of production.

[0011] None of the prior art above suggest a solution to the aforementioned issues of the glazing.SUMMARY OF THE INVENTION

[0012] It is an object of the present invention to provide a lighting laminated glazing and more particularly a laminated glazed roof more simple to produce and with good aesthetic to eliminate the aforementioned problems.

[0013] According to the invention, this object is achieved by a lighting vehicle glazing comprising (a) an external glass pane, (b) an internal glass pane acting as a light guide layer, (c) the first and the second glass panes being laminated together via at least a first plastic interlayer, (d) a glass coupling element optically connected to the outer face of the internal glass pane and (e) a light source being positioned on the outer face of the internal glass pane facing the coupling element.

[0014] According to the present invention, the coupling element comprises a short edge, a long edge opposite to the short edge, and a tapered edge connecting the long and short edges, specifically the coupling element is fixed to the internal glass pane via its short edge. Such configuration allows positioning the light source facing the long edge of the coupling element, defining a larger coupling surface / area for the light emitted from the light source thereby enabling a higher coupling efficiency. A vehicle glazing is thus proposed in which the light emitted by the light source can be coupled into the light guide layer over a large area, specifically by means of the coupling element arranged on the outer surface of the glazing which facing the interior of the vehicle. Moreover the long edge of the coupling element facing the light source enables the positioning / alignment of the light source less prone to tolerances.

[0015] In another aspect of the present invention, the lighting glazing may require less light source for the same lighting effect since the coupling element proposed by the present invention enables a higher light coupling efficiency. Moreover, the energy consumption of the lighting glazing may reduce since more light can be injected into the internal glass pane by the same light source. Furthermore, the coupling elementof the present invention enables a more homogeneous / uniform lighting for the glazing.

[0016] In another aspect of the present invention, the glazing may be utilized more efficiently, meaning that more usable space and more visible area for the passengers. Moreover, the coupling element of the present invention enables integration of other functional elements like roller blind and etc. and yet the visible area for passengers is not compromised. In addition, the coupling element of the present invention may enable more head room for the passengers, especially for the tall passengers.

[0017] In another aspect of the present invention, the coupling element of the present invention may enable ease of production. Moreover, the coupling element of the present invention enables less malfunctioning for the lighting glazing. In addition, the coupling element of the present invention enables affordable lighting glazing since the production times reduce significantly.

[0018] According to one embodiment of the present invention, the light emitted from the light source is focused / directed on the projection of the tapered edge on the long edge, the projection of the tapered edge on the long edge defines a primary coupling area. This embodiment enables maximization of the light coupled to the internal glass pane satisfying the total internal reflection condition by guiding the light over the tapered edge surface, moreover, since the primary coupling area, i.e. , the projection of the tapered edge on the long edge, lies on the far side of the long edge and the light rays are slightly reflected over the tapered edge, a shorter width for the short edge is enough for the light rays to be able to couple into the internal glass pane. Therefore this embodiment enables a shorter width for the short edge of the coupling element, i.e., reduction of the size of the coupling element. In addition, the width of the primary coupling area is preferably larger than the beam size of the light source, therefore it is enabled to direct almost all the light emitted from the light source onto the tapered edge of the coupling element.

[0019] According to another embodiment of the present invention, the width of the short edge is larger than the width of the primary coupling area. Since light reflected from the tapered edge diverges, i.e., the reflected beam size enlarges while traveling through the internal glass pane, a wider short edge than the width of the primary coupling area enables no loss or less losses of the light reflected from the tapered edge. In particular, the width of the short edge is larger than 2.5 mm, specifically largerthan 3 mm, more specifically larger than 4 mm.

[0020] According to another embodiment of the present invention, the thickness of the coupling element is similar to width of the primary coupling area. Thanks to the fixation of the coupling element to the internal glass pane via its short edge, both high coupling efficiency and minimization of the width of the coupling element is realized, therefore the need for a thicker coupling element is eliminated and the thickness of the coupling element is kept in the order of the width of the primary coupling area.

[0021] According to another embodiment of the present invention, a textured layer is provided on the inner face of the internal glass pane in order to couple the light with smaller incident angle to the internal glass pane to satisfy total internal reflection condition by changing the reflected angle to be larger than the incident angle. The textured layer can have a random nonlinear profile that the light with lower / smaller and also higher incident angle, reflected to the outer face of the internal glass pane with larger reflected angle, thereby increasing the light coupled into the internal glass pane satisfying the condition of total internal reflection. The textured layer is aligned with the coupling element, i.e. , the textured layer being on top of the coupling element in the vertical axis and the textured layer being wider than the width of the long edge of the coupling element in order to reflect almost all light rays with smaller incident angle.

[0022] According to another embodiment of the present invention, an alignment means for the light source is provided on the long edge of the coupling element. As the light is mainly focused onto the primary coupling area, the part of the long edge opposite to the primary coupling area is subjected to none or less light rays. The alignment means is provided on said region of the long edge that the light source, preferably the board carrying the light source can be positioned accordingly. This embodiment makes use of the part / region of the coupling element which contributes none or less to the light coupling function.

[0023] With the coupling element proposed by the present invention, glazings with lighting units / systems can be realized as the coupling element fixed on the edge of outer face of the glazing that the lighting unit / system occupies minimum space possible and also the coupling element provides maximum light coupling efficiency possible. On top of that the coupling element of the present invention also provides alignment means for the light source and / or the board carrying the light source andpositioning of the light source can be easily facilitated.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will now be described further, byway of examples, with reference to the accompanying drawings, wherein like reference numerals refer to like elements in the various figures. These examples are provided by way of illustration and not of limitation. The drawings are a schematic representation and not true to scale. The drawings do not restrict the invention in any way. More advantages will be explained with examples. A better understanding of the present invention will be added upon reference to the following description in conjunction with the accompanying drawings.

[0025] Fig.1 is a view of a vehicle with glazing.

[0026] Fig.2 is a schematic top view of the lighting glazing according to one embodiment of the present invention.

[0027] Fig.3 is a schematic side view of the lighting glazing according to one embodiment of the present invention.

[0028] Fig.4 is an illustration of the light rays satisfying total internal reflection condition.

[0029] Fig. 5 and 6 is a schematic cross-section view of the coupling element according to different embodiments of the present invention.

[0030] The elements illustrated in the figures are numbered as follows:1 . Glazing11 . External glass pane12. Internal glass pane13. Interlayer14. Textured layer2. Lighting unit21 . Light source22. Coupling element221 . Short edge222. Long edge223. Tapered edge224. Primary coupling surface23. Optical adhesive24. Alignment meansV. Vehicle t. Thickness of the coupling element ws. Width of the short edge wl. Width of the long edge wp. Width of the primary coupling surfaceDETAILED DESCRIPTION OF THE INVENTION

[0031] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims.

[0032] While some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0033] As used herein, spatial or directional terms, such as "inner", "outer", "above", "below", "top", "bottom", and the like, relate to the invention as it is shown in the drawing figures. However, it is to be understood that the invention can assume various alternative orientations and, accordingly, such terms are not to be considered as limiting. Further, all numbers expressing dimensions, physical characteristics, processing parameters, quantities of ingredients, reaction conditions, and the like, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical values set forth in the following specification and claims are approximations that can vary depending upon the desired properties sought to be obtained by the present invention.

[0034] Moreover, all ranges disclosed herein are to be understood to be inclusive of the beginning and ending range values and to encompass any and all subranges subsumed therein. For example, a stated range of "1 to 10" should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1or more, e.g. 1 to 6.1 , and ending with a maximum value of 10 or less, e.g., 5.5 to 10. Further, as used herein, the terms "deposited over" or "provided over" mean deposited or provided on but not necessarily in surface contact with. For example, a coating "deposited over" a substrate does not preclude the presence of one or more other coating films of the same or different composition located between the deposited coating and the substrate.

[0035] Where the term “comprising” is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun e.g. "a" or "an", "the", this includes a plural of that noun unless something else is specifically stated. In this document, "configured to (or set to)" may be interchangeably used in hardware and software with, for example, "appropriate to", "having a capability to", "changed to", "made to", "capable of", or "designed to" according to a situation. In any situation, an expression "device configured to do" may mean that the device "can do" together with another device or component.

[0036] Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. When it is described that a constituent element (e.g., a first constituent element) is "(functionally or communicatively) coupled to" or is "connected to" another constituent element (e.g., a second constituent element), it should be understood that the constituent element may be directly connected to the another constituent element or may be connected to the another constituent element through another constituent element (e.g., a third constituent element).

[0037] In the following description, unless otherwise specified, expression “substantially” or “around” or “proximity” or “close to” preferably mean to within 10%, preferably to within 5% i.e. , in this context the terms should be understood as in the range of ± 10%, even more ± 5%. Tolerance may be selected depending on the nature of the intended applications.

[0038] In the following description, unless otherwise specified, expression “liquid adhesive”, “optical coupling material”, “optical resin”, “optical coupling adhesive”, “optical clear adhesive” and “liquid resin” are used interchangeably, further expression “functional film”, “film”, “electrically powered functional film” and “electrical functional film” are used interchangeably, further expression “flow”, “fluidic flow”, “liquid flow” and “liquid adhesive flow” are used interchangeably, further expression “external glass pane”, “first glass sheet” are used interchangeably, further expression “internal glass pane”, “second glass sheet” are used interchangeably, further expression “interlayer”, “bonding agent”, “PVB”, “PVB layer”, “plastic interlayer”, “thermoplastic interlayer” are used interchangeably, further expression “light source”, “LED” are used interchangeably, further expression “lighting vehicle glazing” and “lighting glazing” and “glazing” are used interchangeably, further expression “light”, “light beam”, “light ray(s)” are used interchangeably.

[0039] A lighting vehicle glazing (1 ) comprising an external glass pane (11 ) having an outer surface (P1 ) and an inner surface (P2) and an internal glass pane (12) having an inner surface (P3) and an outer surface (P4), acting as a light guide layer, and the external and the internal glass panes (11 , 12) being laminated together via at least a plastic interlayer (13), a light source (21 ) provided in the vicinity of the outer surface (P4) of the internal glass pane (12), at least one coupling element (22) provided in the vicinity of the light source (21 ), and optically bonded to the internal glass pane (12) on its outer surface (P4), that couples the light emitted from the light source (21 ) into the internal glass pane (12), the coupling element (22) having a short edge (221 ), a long edge (222) opposite to the short edge (221 ) and a tapered edge (223) connecting the short (221 ) and long edges (222). The light source (21 ) is provided under the coupling element (22) in the vertical direction, so the order follows as the light source (21 ), the coupling element (22), the internal glass pane (12), the interlayer (13) and the external glass pane (11 ) on top.

[0040] For simplicity, the numbering of the glass panes (11 , 12) in the continuation of the description refers to the numbering nomenclature conventionally used for glazing (1 ). Thus, the face of the laminated glass which is in contact with the environment external to the vehicle is known as being the face 1 (P1 ) and the surface in contact with the internal medium, that is to say the passenger compartment of the vehicle, is known as face 4 (P4).

[0041] In order to avoid any doubt, the terms “external” and “internal” refer to the orientation of the glazing during the installation as glazing in a vehicle. Anyhow, in the description below, these terms are used interchangeably, i.e. , the first glass sheet (11 ) may have face 1 and face 2 or face 3 and face 4 of the glazing, in the meantime the second glass sheet may (12) have face 3 and face 4 or face 1 and face 2, respectively which means first glass sheet (11 ) may be used as external side of the glazing (1 ) or the internal side of the glazing (1 ). Before going into the details of the coupling element (22), definitions for glazing (1 ), structure of the proposed glazing (1 ) will be explained herein.

[0042] According to the invention, the glass sheets (11 , 12) may be a glass of soda- lime-silica, aluminosilicate or borosilicate type, and the like, the composition of the glazing (1 ) is not crucial for the purpose of the present invention.

[0043] According to one example of the present invention, the Fig.2 shows a laminated automotive roof; the roof is intended to be fixed on the vehicle’s body. It is understood that the invention is not limited to a roof and in another preferred embodiment of the present invention, the laminated glazing (1 ) can be used in any glazing for a vehicle (V) and in another preferred embodiment of the present invention, the laminated glazing (1 ) can be used in outside or inside of automotive industry, i.e., anywhere where a laminated glazing (1 ) is needed.

[0044] The glazing (1 ) as shown in Fig.3 as an embodiment of the present invention comprises an external sheet of glass (11 ) having an external surface (P1 ) and an inner surface (P2), and an internal sheet of glass (12) having an inner surface (P3) and an outer surface (P4). Such glazing (1 ) is laminated. The first sheet of glass (11 ) of the glazing (1 ) is that sheet in contact with the exterior of the vehicle. The second sheet of glass (12) is that sheet in contact with the inner space of the vehicle. However, as explained above, the ordering can be changed and also the glazing (1 ) can be a triple glazing or any kind of glazing with at least two glass sheets (11 ,12).

[0045] For avoidance of doubt, the present invention is applicable for all means of transport such as automotive vehicle, vans, lorries, motorbikes, buses, trams, trains, airplanes, helicopters and the like... According to an embodiment of the present invention, the glazing may be a glazed roof, a sidelite, a backlite or a part of windshield of an automotive vehicle as shown in Fig.1 .

[0046] According to one embodiment of the present invention, the first and / or the second sheet of glass (11 , 12) are bent in a previous step before providing a coupling element (22) over at least one surface of the first or the second sheet of glass (11 , 12), i.e., before or after the lamination process. In a version of this embodiment, the curvature values of the first glass sheet (11 ) and the second glass sheet (12) are in line with each other, it has to be understood that the curvature values might not be the same. In another version of this embodiment, the first glass sheet (11 ) has a low curvature and the second glass (12) is flat, this type of glazing (1 ) can also be counted curved glazing. The glass sheets (11 , 12) before the lamination may be totally or partially curved to reach the requested curvature of the final glazing (1 ) to correctly fit with the particular design of the glass support, as the shape required for the application. In another embodiment, the sizes of the two glass sheets (11 , 12) may differ from each other, in common practice, the first glass sheet (11 ) with P1 and P2 surfaces is bigger than the second glass sheet (12) with P3 and P4 surfaces. In any embodiment where the glazing (1 ) having a curvature which can be in one direction or in two directions, the coupling element (22) of the present invention is also bended in order to conform with the curvature of the glazing (1 ), since the coupling element (22) is made of glass, bending of the coupling element (22) can be realized with the known conventional methods. However, the curvature or the sizes of the glazing (1 ) is not crucial for the present invention.

[0047] According the invention, the term "laminating" refers to a step of providing a layered structure in which one or more glass sheets (11 , 12) are separated by an interlayer (13) acting as a bonding agent extending across substantially the entire interface between the glass sheets (11 , 12). The glazing (1 ) is comprising at least one interlayer (13) as bonding layer for the substrate sheets (11 , 12). The interlayer (13) may be one of the conventional interlayers used in lamination processes, examples of the interlayer (13) are EVA, TPO, POE, PVB, TPU, Ionomers, and etc. which are widely known and used in both automotive and architecture industry. The interlayer (13) can be clear or transparent or colored. For the sake of the invention, the material or other properties of the interlayer (13) is not utmost important.

[0048] The light source (21 ) is provided in the vicinity of the outer surface (P4) of the internal glass pane (12), more specifically the light source (21 ) is being positioned on the outer face (P4) of the internal glass pane (12) facing the coupling element (22),such positioning of the light source (21 ) is illustrated in the figures 3 and 4, in other words, the light source (21 ) is provided under the coupling element (22) in the vertical direction that the lighting glazing (1 ) of the present invention is considered bottom-lit lighting glazing. The light source (21 ) can be designed in particular as a high- performance LED module, is an LED bar or an LED strip with a large number of LEDs, which emit their light directly into the coupling element (22) or a lightguide that can emit light from its sides at predetermined intervals. In another embodiment, the light source (21 ) is optical fibers to transmit light, a waveguide combined with LEDs or laser diodes. The light source (21 ) may also comprise a lens (not shown) to collimate and / or focus the light emitted onto the coupling element (22), in the preferred version the light beam hitting on the coupling element (22) is collimated. For the sake of the invention, the properties of the light source (21 ) is not utmost important.

[0049] The coupling element (22) is provided in the vicinity of the light source (21 ), and optically bonded to the internal glass pane (12) on its outer surface (P4), that couples the light emitted from the light source (21 ) into the internal glass pane (12). The coupling element (22) having a short edge (221 ), a long edge (222) opposite to the short edge (221 ) and a tapered edge (223) connecting the short (221 ) and long edges (222) and optically connected to the outer face (P4) of the internal glass pane (12) and is made of glass.

[0050] According to the present invention, the coupling element (22) may be arranged onto the outer face (P4) of the internal glass pane (12) in case of glazing is a laminated glazing or onto the inner face (P2) of the glazing in case of the glazing is a toughened safety glass and tempered safety glass, therefore the present invention is not limited to laminated glazings.

[0051] According to the present invention, the coupling element (22) can be attached directly to the outer face (P4) of the internal glass pane (12) via an optical adhesive (23), such optical adhesives (23) are widely known. The coupling element (22) may also have curvature in order to conform with the curvature of the glazing (1 ). The coupling element (22) is preferably coupled to the light source (21 ). Thus, the coupling element (22) is provided in the vicinity of the light source (21 ) and is preferably in contact with it (direct contact or not) to be able to couple the light coming out from the light source (21 ) to the coupling element (22). Moreover, the light source (21 ) and the coupling element (22) form a lighting unit (2), the lighting unit (2) may comprise otherelements such as the optical adhesive (23).

[0052] As shown in figures 3 to 6, the axis are defined as follows. Z-axis is the vertical axis that at any given point on the surface of the glazing (1 ), the z-axis is perpendicular to the glazing surface. X-axis is defined as the parallel axis to the edge of the glazing (1 ) where the lighting unit (2) extends. Y-axis is defined as the perpendicular axis to the x-axis and z-axis, wherein the edges and the width (ws, wi, wp) of the coupling element (22) and the light source (21 ) are defined. Therefore, the thickness (t) of the coupling element (22) should be understood as the length of the edge of the coupling element (22) in the z-axis, and the width (ws, wi, wp) of the coupling element (22) should be understood as the length of the edge of the coupling element (22) in the y-axis and the short (221 ) and long edge (222) of the coupling element (22) are also defined in the y-axis.

[0053] According to the present invention, the light emitted by the light source (21 ) is pointing towards the coupling element (22) and the light propagates into the coupling element (22) as the incident angle is almost zero degree, i.e., light beam is substantially perpendicular to the edge of the coupling element (22), the incident angle is defined as the angle between the incoming light ray and the normal of the surface light ray directed. Then the light inside the coupling element (22) hit the tapered edge (223) and the light rays are reflected towards the internal glass pane (12) as illustrated in Fig.4. Since the coupling element (22) is made of glass, the light directed towards the internal glass pane (12) propagates into the internal glass pane (12) almost without changing its direction. Then the light reflects from the inner surface (P3) of the internal glass pane (12) satisfying total internal reflection condition thanks to the structural design of the coupling element (22). Afterwards, the light coupled into the internal glass pane (12) illuminates the interior of the vehicle, in some embodiments the internal glass pane (12) may have a pattern (not shown) on its P4 or P3 surface that the users perceive an illuminated pattern, in other embodiments, the illumination can be achieved with a film layer laminated inside the glass panes, especially film layer facing the P3 surface of the internal glass pane. How the illumination of the glazing (1 ) works is very well known and the present invention is about the improvements related to the coupling element (22).

[0054] The lighting vehicle glazing (1 ) of the present invention comprises the short edge (221 ) of the coupling element (22) is attached onto the inner surface (P4) of theinternal glass sheet (12). The coupling element (22) is attached onto the glazing (1 ) via its short edge (221 ), such attachment may be realized by an adhesive (23) compatible for glass to glass contact. By providing the short edge (221 ) of the coupling element (22) fixed onto the inner surface (P4) of the internal glass sheet (12), it is provided that the long edge (222) of the coupling element (22) faces the light source(21 ) and enables more coupling surface for the light emitted. In addition to enabling more light to be coupled to the internal glass pane (12), provision of long edge (222) facing the light source (21 ) enables the light source (21 ) less prone to positioning with respect to the coupling element (22).

[0055] In one embodiment of the present invention, the lighting vehicle glazing (1 ) comprises a primary coupling surface (224) provided on the projection of the tapered edge (223) on the long edge (222) wherein the light source (21 ) is focused. The light source (21 ) is focused onto the primary coupling surface (224) defined as the part of the long edge (222) where the tapered edge (223) is projected. Therefore the light beams emitted from the light source (21 ) entered the coupling element (22) are reflected from the tapered edge (223) to the internal glass pane (12), enables the angle of incidence of the reflected beam on the inner surface (P3) of the internal glass pane (12) converging the critical angle for total internal reflection. Moreover realization of such primary coupling surface (224) maximizes the light being coupled into the internal glass pane (12) satisfying the total internal reflection condition. One another advantage of the primary coupling surface (224), i.e. , the light emitted focused onto the projection of the tapered edge (223), enables the reduction of the width (ws) of the short edge (221 ), in other words, with this embodiment a smaller coupling element(22) may be used without reducing the amount of light coupled into the internal glass pane (12).

[0056] In another embodiment of the present invention, the width (wp) of the primary coupling surface (224) is larger than the beam size of the light source (21 ). In order to capture most of the light emitted from the light source (21 ), the width (wp) of the primary coupling surface (224) is made as larger than the beam size of the light source (21 ). In a version of this embodiment, a converging lens (not shown) is provided inbetween the light source (21 ) and the coupling element (22). The lens provides a narrower beam size arriving the coupling element (22) even if the light emitted from the light source (21 ) has a larger beam size.

[0057] In another embodiment of the present invention, the width (ws) of the short edge (221 ) is larger than the width (wp) of the primary coupling surface (224). As the reflected light beam from the tapered edge (223) widens as it propagates, width (ws) of the short edge (221 ) is larger than the width (wp) of the primary coupling surface (224) to be able to direct most of the light into the internal glass pane (12).

[0058] In another embodiment of the present invention, the minimum width (ws) of the short edge (221 ) is larger or equal to 2.5 mm, preferably 3 mm, more preferably 4 mm. As disclosed in the above embodiments, the width (ws) of the short edge (221 ) should be larger than a predefined value, i.e., the short edge (221 ) cannot be minimized more than a limit value. In order not to compromise the amount of light coupled to the internal glass pane (12) satisfying total internal reflection condition and also satisfying the maximization of the usable area of the glazing (1 ), the width (ws) of the short edge (221 ) should be at least 2.5 mm. The given minimum values are preferably for a point source light source (21 ).

[0059] In another embodiment of the present invention, the maximum width (ws) of the short edge (221 ) is 25 times of the width (wp) of the primary coupling surface (224), preferably 20 times, more preferably 15 times, even more preferably 10 times of the width (wp) of the primary coupling surface (224). As the reflected light beam from the tapered edge (223) widens propagating through the internal glass pane (12), a wider short edge (221 ) enables more light to be coupled as satisfying the total internal reflection condition. When the width (ws) of the short edge (221 ) is more than a predefined maximum limit value, the light coupled into the internal glass pane (12) escapes through the coupling element (22) upon being reflected from inner surface (P3) of the internal glass pane (12).

[0060] In another embodiment of the present invention, the thickness (t) of the coupling element (22) is similar to the width (wp) of the primary coupling surface (224), i.e., in the order of the width (wp) of the primary coupling surface (224). More specifically the thickness (t) of the coupling element (22) is in the range of the width (wp) of the primary coupling surface (224) with ± 20% margin. The thickness (t) of the coupling element (22) should be large enough to enable a tapered edge (223) for light to be reflected and it has been found out through various experiments that a thickness value (t) in the order of the width (wp) of the primary coupling surface (224) as the minimum thickness (t) for the coupling element (22) enables an adequate amount oflight coupled to the internal glass pane (12).

[0061] In another embodiment of the present invention, the tapered edge (223) is an inclined edge with angle of 40 to 60 degree with the long edge (222) as shown in figure 3 and 4. Such configuration enables light rays incident on the P3 surface of the internal glass pane (12) to satisfy the total internal reflection condition for almost all interlayers(13) used in the automotive industry, as the critical angle for the total internal reflection is defined by the refractive indices of the interlayer (13) and the internal glass pane (12).

[0062] In another embodiment of the present invention, the tapered edge (223) is a curved edge as shown in figure 5. In a different version of this embodiment, the tapered edge (223) is segmented as shown in figure 6. Such configurations enable the beam reflected from the tapered edge (223) to approach to the P3 surface of the internal glass pane (12) with a converging incident angle close to the critical angle for the total internal reflection condition.

[0063] In another embodiment of the present invention, the lighting vehicle glazing (1 ) comprises a textured layer (14) provided on the P3 surface of the internal glass pane (12). The textured layer (14) may be realized by wet etching of the relevant area on the P3 surface or by laser patterning of the relevant area on the P3 surface or by coating of an appropriate material on the relevant area on the P3 surface or a textured film provided on the relevant area on the P3 surface or a paint layer provided on the P3 surface or application of pigments on the relevant area of the P3 surface or any other conventional method. The textured layer (14) enables light rays that cannot be coupled satisfying total internal reflection inside the internal glass pane (12) to be couple by alternating the reflected angle. Thus, the light rays with incident angle smaller than the critical angle of TIR condition can be coupled inside the internal glass pane (12), one example of a textured layer (14) is shown in Fig. 3.

[0064] In another embodiment of the present invention, the coupling element (22) is aligned with the textured layer (14). The textured layer (14) is provided on the P3 surface inline with the coupling element (22) in the z-axis, thus the light rays provided by the light source (21 ) hits to the textured layer (14).

[0065] In another embodiment of the present invention, the width of the textured layer(14) is larger than the width (wi) of the long edge (222). The light rays travelling insidethe internal glass pane (12) diverges and the total area illuminated on the P3 surface is larger than the original beam size. A larger textured layer (14) than the long edge (222) of the coupling element (22) enables almost all light rays with incident angle smaller than the critical angle for total internal reflection condition to hit onto the textured layer (14).

[0066] In a version of this embodiment, the textured layer (14) is at least partially surrounding the projection of the coupling element (22) on the P3 surface as illustrated in Fig. 4, i.e. , no textured layer (14) for the light rays hitting the P3 surface with incident angle inbetween critical angle and a predetermined angle larger than the critical angle and the textured layer (14) is present on the P3 surface for the light rays (dashed line in Fig.4) with the incident angle smaller than the critical angle and also for the light rays with incident angle larger than the predetermined angle. Apart from enabling the light with smaller incident angle to be coupled to the internal glass pane (12) by alternating the reflecting angle to satisfy the total internal reflection condition, the reflected angle of the light with a higher incident angle than the predetermined angle is also alternated to be smaller so that the distance on the P4 surface of the internal glass pane (12) inbetween the reflections of the same light ray get shortened, thus enabling a more tightly spaced pattern for illumination possible.

[0067] In another embodiment of the present invention, the lighting vehicle glazing (1 ) comprises a blocking layer (not shown) provided on the P3 surface of the internal glass pane (12) or on the P2 or P1 surface of the external glass pane (11 ) preferably aligned with the light source (21 ) in the vertical axis. The blocking layer is a layer that is totally opaque or totally reflective or totally absorbing that the blocking layer enables no light be seen from the outside of the vehicle, especially the light source (21 ). Implementation of such blocking layer can be achieved in various different methods.

[0068] In another embodiment of the present invention, the lighting vehicle glazing (1 ) comprises an alignment means (24) provided on the long edge (222). The alignment means (24) enables the light source (21 ) to be aligned with the coupling element (22) and facilitates the installation. The alignment means (24) may be a notch or a cavity or any other means helping alignment of the light source (21 ). The alignment means (24) is preferably situated on the opposite side of the primary coupling surface (224), i.e., the alignment means (24) and the primary coupling surface (224) are far away from each other in y-axis. The light source (21 ) may be on a circuit board and thecircuit board has a means to fit or align with the alignment means (24) on the coupling element (22). With this embodiment, the need of an alignment means (24) is realized on the non-used part of the long edge (222) of the coupling element (22).

[0069] In another embodiment of the present invention, the lighting vehicle glazing (1 ) of the present invention is a vehicle roof glazing.

[0070] In another embodiment of the present invention, the lighting glazing (1 ) may comprise a black enamel layer (not shown) provided on the periphery of the glazing (1 ). Such black enamel layer is also known as black band in the automotive industry and it is very well known.

[0071] In another embodiment of the present invention, the lighting glazing (1 ) may comprise a coating (not shown) for thermal management, preferably a low emissivity coating provided on P4 surface of the glazing (1 ) or a metallic coating provided on different surfaces (P1 , P2, P3, P4) of the glazing (1 ), provided the area where the coupling element (22) is fixed onto glazing (1 ) surface free of coating. Such thermal management coatings are effective to keep the internal heat inside the vehicle and / or keeping the outside heat away from the vehicle.

[0072] In another embodiment of the present invention, the lighting glazing (1 ) also comprises photovoltaic solar cells (not shown) laminated inbetween the external (11 ) and internal glass panes (12). The photovoltaic solar cells are producing electricity from the sun.

[0073] In another embodiment of the present invention, the lighting glazing (1 ) also comprises a functional film (not shown) laminated inbetween the external (11 ) and internal glass panes (12). The functional film may comprise liquid crystals and perform dimming function or else.

[0074] With this invention, the lighting glazings (1 ) can be realized more affordably and providing more room for the passengers and also the manufacturer to integrate elements like roller blind without compromising the aesthetics of the vehicle since the lighting glazing (1 ) is already a bottom-lit lighting glazing occupying narrow space and also the coupling element (22) of the present invention enables it to be even narrower and thinner. Moreover with the coupling element (22) of the present invention, the running costs for the lighting glazing (1 ) are reduced significantly since more light can be coupled into the internal glass pane (12) than prior art examples.

[0075] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention may be practiced in many ways.The invention is not limited to the disclosed embodiments.

Claims

Claims1 . A lighting vehicle glazing (1 ) comprising an external glass pane (11 ) having an outer surface (P1 ) and an inner surface (P2) and an internal glass pane (12) having an inner surface (P3) and an outer surface (P4), acting as a light guide layer, and the external and the internal glass panes (11 , 12) being laminated together via at least a plastic interlayer (13), a light source (21 ) provided in the vicinity of the outer surface (P4) of the internal glass pane (12), at least one coupling element (22) provided in the vicinity of the light source (21 ), and optically bonded to the internal glass pane (12) on its outer surface (P4), that couples the light emitted from the light source (21 ) into the internal glass pane (12), the coupling element (22) having a short edge (221 ), a long edge (222) opposite to the short edge (221 ) and a tapered edge (223) connecting the short (221 ) and long edges (222); characterized in that the short edge (221 ) of the coupling element (22) is attached onto the inner surface (P4) of the internal glass sheet (12).

2. A lighting vehicle glazing (1 ) according to claim 1 , characterized in that a primary coupling surface (224) provided on the projection of the tapered edge (223) on the long edge (222) wherein the light source (21 ) is focused.

3. A lighting vehicle glazing (1 ) according to claim 2, characterized in that the width (wp) of the primary coupling surface (224) is larger than the beam size of the light source (21 ).

4. A lighting vehicle glazing (1 ) according to claims 2 or 3, characterized in that the width (ws) of the short edge (221 ) is larger than the width (wp) of the primary coupling surface (224).

5. A lighting vehicle glazing (1 ) according to anyone of preceding claims, characterized in that the minimum width (ws) of the short edge (221 ) is larger or equal to 2.5 mm, preferably 3 mm, more preferably 4 mm.

6. A lighting vehicle glazing (1 ) according to claims 2 to 5, characterized in that the maximum width (ws) of the short edge (221 ) is 25 times of the width (wp) of the primary coupling surface (224).

7. A lighting vehicle glazing (1 ) according to claims 2 to 6, characterized in that the thickness (t) of the coupling element (22) is similar to the width (wp) of the primary coupling surface (224).

8. A lighting vehicle glazing (1 ) according to anyone of preceding claims, characterized in that the tapered edge (223) is an inclined edge with angle of 40 to 60 degree with the long edge (222).

9. A lighting vehicle glazing (1 ) according to anyone of claims 1 to 7, characterized in that the tapered edge (223) is a curved edge.

10. A lighting vehicle glazing (1 ) according to anyone of claims 1 to 7, characterized in that the tapered edge (223) is a segmented edge.

11. A lighting vehicle glazing (1 ) according to anyone of preceding claims, characterized in that a textured layer (14) provided on the P3 surface of the internal glass pane (12).

12. A lighting vehicle glazing (1 ) according to claim 11 , characterized in that the coupling element (22) is aligned with the textured layer (14).

13. A lighting vehicle glazing (1 ) according to claims 11 or 12, characterized in that the width of the textured layer (14) is larger than the width (wi) of the long edge (222).

14. A lighting vehicle glazing (1 ) according to any of the preceding claims, characterized in that an alignment means (24) provided on the long edge (222).

15. A vehicle roof glazing comprising the lighting vehicle glazing (1 ) according to any of the preceding claims.

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