LIGHTING GLAZING UNIT FOR A VEHICLE

Description

[0001] The present invention relates to an illuminating glazing for vehicles, comprising light-emitting diodes housed within a hole drilled in at least one sheet of the glazing. It also relates to a vehicle comprising such glazing.

[0002] It is known to incorporate light-emitting diode modules (LED modules) at the edge of single or laminated glazing, so that the light emitted by the LEDs enters through the edge of a sheet of glass and is guided by it to a diffusing element, also called a light extraction means.

[0003] These illuminated glazings essentially have an ambient lighting or light signaling function which is achieved with low-power LEDs. The luminous efficiency of such edge-lit glazings is generally limited due to light losses due to light absorption by the glass serving as a waveguide and / or the materials near it.

[0004] The approach of trying to overcome this problem by using more powerful LEDs, however, poses a problem of overheating. Indeed, the evacuation of the heat generated by LED modules during operation in a confined environment very often proves difficult. In the automotive and other vehicle sectors, it is often necessary to protect LED modules against the action of omnipresent humidity. This protection is commonly achieved either by encapsulation, i.e. overmolding the LED modules with an organic polymer injected in liquid form and then hardened, or by housing the LED modules, in a removable or non-removable manner, in more or less sealed housings. However, prolonged overheating of LEDs almost inevitably results in an undesirable reduction in their lifespan.

[0005] From DE 10 2004 039883 B3 a glass element is known, comprising at least a first transparent pane, a second, preferably transparent, pane, and an LED. From US 2008 / 117355 A1 a surface light source device comprising a light guide and horizontal point light sources and a liquid crystal display device comprising the surface light source device is further known.

[0006] The present invention is based on a very different approach than that described above. Rather than trying to use ever more powerful LEDs, the idea was to improve the overall light output of the glazing by shortening the optical path traveled by the light between the LED and the extraction means which extracts the light from the waveguide (glass sheet) and diffuses it towards the inside and / or outside of the vehicle.

[0007] Rather than moving the light extraction means closer to the peripheral edge of the sheet, the idea was to create an additional edge close to the extraction means by drilling a through hole in the illuminated glass sheet. This hole must be large enough to accommodate one or more LEDs which inject light through the additional edge, which is immediately extracted by the extraction means in the immediate vicinity of the hole.

[0008] This technical solution reduces the optical path traveled by the light before extraction to just a few centimeters. The luminous efficiency and lighting power of such glazing are independent of the distance between the extraction means and the edge of the glazing. The creation of one or more additional slices makes it possible to considerably enlarge the injection surface and multiply the number of light sources, whether low or high power.

[0009] The present invention therefore relates to illuminating glazing for a vehicle, as defined in claim 1.

[0010] Of course, the present invention also encompasses illuminating glazings that have several through holes containing LEDs. These holes can have various geometric shapes that are mainly limited by the technical feasibility of the drilling process and by the strength of the pierced glass sheets. At the time the invention was made, circular or rectangular shapes, preferably with rounded corners, gave the best results in terms of sheet strength and ease of drilling. However, other, more complex hole shapes, which would become technically easier to achieve in the coming years are of course also encompassed.

[0011] The through-hole(s) are large enough to accommodate several LEDs or several LED modules. However, they must not exceed a certain size beyond which the strength of the glazing may be significantly reduced. The extent of each through-hole preferably does not exceed 100 cm 2< , and is advantageously between 10 and 50 cm 2< .

[0012] The glazing according to the invention is a laminated glazing, that is to say it comprises, in addition to the first sheet, a second transparent sheet of mineral glass with a first main face, a second main face and a peripheral edge, and a lamination interlayer, also transparent, which is in adhesive contact with the two sheets of glass, and more precisely with the second main face of the first sheet and the first main face of the second sheet.

[0013] In the present application the term "first sheet" always designates the sheet pierced and illuminated by the internal edge of the hole. The second sheet is generally not illuminated. The glazing of the invention is preferably mounted on the vehicle so that the first sheet is the one in contact with the passenger compartment of the vehicle and the second sheet is the one located further towards the outside of the vehicle, often in direct contact with the atmosphere outside the vehicle.

[0014] The term "first main surface" designates, both in relation to the first and the second sheet, the face of the sheet facing the interior of the vehicle. Logically, the term "second main surface" then designates the surface of each sheet directed or intended to be directed towards the exterior of the vehicle.

[0015] Preferably, a colorless soda-lime mineral glass such as Planilux ® glass marketed by the Applicant will be used for the first sheet. The first sheet typically has a thickness of between 2.5 and 6 mm when it is single glazing, and a thickness of between 1.4 and 3.2 mm, preferably between 1.4 and 2.1 mm when it is laminated glazing.

[0016] The second sheet can of course be as transparent and colorless as the first sheet. In one embodiment, a laminated glazing according to the invention will consist of two colorless Planilux ® sheets.

[0017] Unlike the first sheet, the second sheet is advantageously made of tinted glass, for example Venus ®, TSA3+ or TSA4+ glass also marketed by the Applicant. The second sheet typically has a thickness of between 1.4 and 2.1 mm.

[0018] The second sheet may be larger than the first, thus extending beyond the latter over at least part of its circumference. This variant could be advantageous when the first sheet is illuminated not only by the through-hole but also by its peripheral edge. The additional lighting system, by the peripheral edge, comprising the LED modules can then be supported on the first face of the second sheet, where it extends beyond the first sheet.

[0019] The lamination interlayer used in laminated glazing can be made of any transparent polymer material commonly used for this purpose, for example poly(vinyl butyral) (PVB), thermoplastic polyurethane (TPU) or ethylene vinyl acetate copolymer (EVA). It typically has a thickness of between 0.2 and 1.1 mm and can be colorless or tinted.

[0020] In the case of laminated glazing not covered by the claims, the through hole may be limited to the first sheet. In the case of the laminated glazing according to the invention, the through hole extends through the lamination interlayer and the second transparent sheet. In this case, the drilling is preferably carried out on the glazing after lamination.

[0021] In the case where the hole extends through the entire thickness of the glazing, the through hole in the second sheet is advantageously filled with an obstruction element. This obstruction element has the function essentially of masking the LED modules located in the hole and of ensuring tightness against liquid water and preferably also against water vapor, so as to protect the LED modules and the passenger compartment from external humidity.

[0022] Any suitable material known and commonly used for this purpose may be used, preferably an opaque polymeric material, whether elastomeric or not, which may optionally be attached to the second sheet by means of a seal. This may include an encapsulating element formed by reaction injection molding (RIM, reaction injection moulding )

[0023] The light extraction element is located in the immediate vicinity of the through hole. Indeed, the light output decreases sharply as the distance between the light source and the light diffusion means increases. The distance separating the inner edge of the hole from the light extraction element is at most 20 cm, in particular at most 10 cm, and ideally at most 5 cm. This distance is that between the inner edge and the point of the extraction means closest to this inner edge.

[0024] As already indicated above, the light extraction means is located on one of the main faces of the illuminated sheet. When it comes to diffusing the light towards the interior of the vehicle, the extraction means is preferably an opaque diffusing coating, preferably white in color, located at the second main face of the first sheet. This embodiment is in fact more advantageous than a semi-opaque coating located on the first main face of the first sheet and which would only diffuse part of the light towards the interior of the vehicle, a significant part being diffused towards the exterior of the vehicle.

[0025] Conversely, when it is desired to diffuse the light mainly towards the outside of the vehicle, for example in the case of a traffic light, the opaque diffusing coating is advantageously located on the first main face of the illuminated sheet, that is to say on the innermost face of this sheet.

[0026] The light extraction element may be in the form of one or more diffusing zones, arranged around the through hole. It is particularly advantageously in the form of a centrally symmetrical pattern, the center of symmetry of this pattern preferably being superimposed on the center of symmetry of the through hole or in the form of an axially symmetrical pattern, the axis of symmetry preferably being superimposed on an axis of symmetry of the through hole.

[0027] This superposition of the centers of symmetry is not only very satisfactory from an aesthetic point of view, but also contributes to a uniform brightness of the light extraction medium.

[0028] The power supply to the LEDs located in the through hole can be provided by a power supply integrated into the laminated glazing, for example an electric wire incorporated in the lamination interlayer, or this electric wire can be applied to the first main face of the first sheet (passenger compartment side), and possibly be protected by a cover.

[0029] The through hole in the first sheet in which the LEDs are housed is advantageously closed by a cover, preferably a removable cover, fixed to the internal edge of the through hole or to the first main face of the first sheet by reversible fixing means.

[0030] This cover can be an opaque cover whose main function is to hide the LED modules from the eyes of the vehicle's passengers.

[0031] The Applicant has however also considered an embodiment, represented in the figure 2 , where the cover is translucent (diffusing) or transparent and where the through hole contains not only LEDs injecting their light into the internal edge, but also LEDs whose emitting face is not opposite the internal edge but opposite the cover.

[0032] This embodiment, which combines direct lighting through the transparent or translucent cover with indirect lighting via the light extraction means, is distinguished by a particularly advantageous light output.

[0033] The Applicant also considered an embodiment, shown in figure 3 , where additional LEDs send their light not towards the inside, but towards the outside of the vehicle, through a translucent enamel, i.e. diffusing and semi-transparent, applied to one of the main faces of the second sheet, preferably the first face of the second sheet.

[0034] This latter embodiment corresponds, for example, to a signal light such as a turn signal repeater, integrated into a vehicle window.

[0035] The present invention also relates to a vehicle comprising illuminating glazing as described above. As already explained above, in such a vehicle the first main face of the first sheet of glazing is in contact with the interior of the vehicle.

[0036] The vehicle may be an airplane, boat, or any land vehicle. The glazings of the present invention are preferably used in motor vehicles, particularly as part of the roof of a motor vehicle.

[0037] The present invention will now be described in more detail with reference to the accompanying drawings in which there figure 1 shows a first embodiment of illuminating glazing according to the invention. figure 2 shows a second embodiment which differs from that of the figure 1 by the fact that it also includes LEDs for direct lighting of the passenger compartment, and the figure 3 shows a third embodiment where direct-lighting LEDs diffuse their light towards the exterior of the vehicle.

[0038] The methods of realization of the figures 2 et 3 are not part of the invention.

[0039] The illuminating glazing shown in the figure 1 is a laminated glazing comprising a first sheet 1 with a first main face 11 facing the inside of the vehicle, a second main face 12 facing the outside of the vehicle and a peripheral edge (not shown). This first glass sheet is bonded via a laminating intermediary 5 to a second glass sheet 2 with a first main face 21, a second main face 22 and a peripheral edge (not shown).

[0040] A through hole 4 has been drilled through the second sheet 2, the lamination interlayer 5 and the first sheet 1, creating in the latter an internal slice 14. The through hole in the second sheet is obstructed by an opaque obstruction element 6 flush with the second surface 22 of the second sheet.

[0041] In the through hole 4 of the first sheet are housed LEDs 3 with their emitting face 31 facing the internal edge 14. The LED modules are supported by a removable opaque cover 9, fixed via clips 16 to the first main surface 11 of the first sheet. The light extraction means 7 is located in the immediate vicinity of the inner edge 14. This is a light-colored opaque enamel located on the second main face 12 of the first sheet. An opaque masking enamel 8 on the first main face 21 of the second sheet 2 is provided to prevent direct emission of light by the LEDs 3 to the outside of the vehicle.

[0042] Although not shown in this figure, the through hole 4, the LED module 3, the opaque cover 9 and the light extraction means 7 have a central circular symmetry.

[0043] There figure 2 shows an embodiment where the second sheet 2 does not have a through hole. An opaque black enamel 8 on the first main face 21 of the second sheet 2 here acts as a masking element towards the outside. On this enamel 8 is fixed an LED module comprising a plurality of LEDs 3 arranged so that their emitting faces 31 are opposite the internal edge 14 of the through hole 4 drilled in the first sheet 1. These side-emitting LEDs send the light into the first sheet 1 from where it is extracted by the extraction means 7 which is here a light-colored semi-transparent enamel, located on the first main face 11 of the first sheet. In addition to the side-emitting LEDs 3 for indirect lighting, a front-emitting LED module 15 is arranged in the center of the hole, its emitting face 18 oriented towards the interior of the vehicle.The light emitted by this LED 15 is diffused by the translucent diffusing cover 9 reversibly fixed to the first main face of the first sheet 11 by means of clips 16.

[0044] There figure 3 watch, like the figure 2 , an embodiment combining direct and indirect lighting, these two types of lighting being emitted here towards the outside of the vehicle. The through hole 4 has been drilled only in the first sheet and the lamination interlayer 5, while the second sheet is not drilled. The opaque cover 9 fixed to the first main face 11 of the first sheet by a bead of glue 16 carries a circular LED module with side-emitting LEDs 3, their emitting face 31 facing the internal edge 14 of the hole 4. The light injected by these LEDs 3 into the first sheet 1 is immediately extracted and diffused towards the outside by an opaque enamel 7 on the first main face 11 of the first sheet.

[0045] Front-emitting LEDs 15 are arranged, with their emitting face 18 directed towards the second sheet 2, in the centre of the LED module 3. The light emitted by these LEDs 15 is diffused by a semi-opaque diffusing enamel 19 on the first main face of the second sheet, towards the outside of the vehicle.

Claims

1. An illuminating glazing unit for vehicles, comprising - a first transparent sheet (1) of mineral glass with a first main face (11), a second main face (12), and a peripheral edge, - a second transparent sheet (2) of mineral glass with a first main face (21), a second main face (22), - a transparent lamination interlayer (5) which is in adhesive contact with the second main face (12) of the first sheet and the first main face (21) of the second sheet, - a plurality of light-emitting diodes (LEDs) (3), each having an emitting face (31), and - a light extraction element (7), located on one of the main faces of the first sheet, characterized in that the first sheet is pierced with a through hole (4) delimited by an internal edge (14), in that one or more LEDs (3) are housed in the through hole (4), with their emitting faces (31) turned toward the internal edge (14), in that in that the through hole (4) extends through the lamination interlayer (5) and the second transparent sheet (2) and in that the light extraction element (7) is located in the immediate proximity of the through hole, the distance separating the internal edge (14) from the light extraction element (7) is not more than 20 cm, or preferably not more than 10 cm, and particularly not more than 5 cm.

2. The illuminating glazing unit as claimed in claim 1, characterized in that the through hole in the second sheet (2) is filled with a blocking element (6), preferably an opaque polymer material.

3. The illuminating glazing unit as claimed in any one of the preceding claims, characterized in that the light extraction element (7) is an opaque diffusing coating, preferably white in color, located on the second main face (12) of the first sheet (1).

4. The illuminating glazing unit as claimed in any one of the preceding claims, characterized in that the light extraction element takes the form of one or more areas arranged around the through hole (4).

5. The illuminating glazing unit as claimed in claim 4, characterized in that the light extraction element (7) takes the form of a pattern with central symmetry, the center of symmetry of this pattern being preferably superimposed on the center of symmetry of the through hole (4), or the form of a pattern with axial symmetry, the axis of symmetry being preferably superimposed on an axis of symmetry of the through hole (4).

6. The illuminating glazing unit as claimed in any one of the preceding claims, characterized in that the through hole (4) in which the LEDs (3) are housed is closed by a cover (9).

7. The illuminating glazing unit as claimed in claim 6, characterized in that the cover (9) is an opaque cover.

8. The illuminating glazing unit as claimed in claim 6, characterized in that the cover (9) is made of a translucent or transparent material, and in that the glazing unit additionally contains LEDs (15) whose emitting faces (18) are turned toward the cover (9) instead of toward the internal edge (14).

9. The illuminating glazing unit as claimed in the preceding claim, characterized in that the cover (9) is a removable cover, fixed onto the first main face (11) of the first sheet (1) by reversible fixing means (10).

10. A vehicle having an illuminating glazing unit as claimed in any one of the preceding claims, characterized in that the first main face (11) of the first sheet (1) of the glazing unit is in contact with the inside of the vehicle.

11. The vehicle as claimed in the preceding claim, characterized in that it is a motor vehicle.

12. The vehicle as claimed in the preceding claim, characterized in that the illuminating glazing unit is part of the roof of the vehicle.