WO2013079832A1

WO2013079832A1 - Illuminating glazing unit

Info

Publication number: WO2013079832A1
Application number: PCT/FR2012/052060
Authority: WO
Inventors: Adèle VERRAT-DEBAILLEUL; Pascal BÄUERLE; Laurent Lamoureux; Pascal Lefevre; Mathieu Berard; Jean-Philippe Mulet
Original assignee: Saint-Gobain Glass France
Priority date: 2011-09-29
Filing date: 2012-09-14
Publication date: 2013-06-06
Also published as: FR2980833A1

Abstract

The present invention relates to an illuminating glazing unit, preferably an illuminating glazing unit for a vehicle, comprising: a first sheet (1), made of mineral or organic glass, with a first main face (11), a second main face (12), and an edge face (13); at least one waveguide (2) with -at least one first end face (21) where light enters, -at least one second end face (22) where light exits, facing the edge face (13) of the first sheet (1), -a first main guiding face (23), -a second main guiding face (24), and -a face (25) for bending light, connecting the second main guiding face (24) to the second end face (22) where light exits, and designed so as to change the main direction of propagation of the light by an angle at least equal to 90°; and one or more light sources (3) each comprising an emitting face (31) facing the end face (21) where light enters; one or more elements for extracting light (37); and at least one encapsulating element (6).

Description

GLAZING LIGHTING

The present invention relates to an illuminating vehicle glazing comprising a waveguide of a particular shape for moving the light source, in particular light-emitting diodes, to a position not covered by the encapsulation.

WO2006 / 128941 and WO2011 / 092419 disclose illuminating roofs for vehicles comprising light-emitting diodes (LEDs) located at the edge of the sheets forming the glazing and covered by the encapsulation.

Encapsulated LED systems have the main disadvantages

a low luminous efficiency with a loss of luminosity, following encapsulation, which can go up to almost 80%,

the impossibility, in the event of failure of the encapsulated LEDs, to replace them without destroying the encapsulation, and

The frequent existence of undesirable light spots on the outside of the glazing, vis-à-vis the light sources, due to light leakage on the side of the glazing opposite to the extraction face of the light.

The present invention aims to solve the above problems and in particular that of the impossibility of replacing encapsulated LEDs. This goal has been achieved thanks to a system where the light sources are located near the edge of the glazing, but outside the encapsulation zone or an area with premounted joint and / or a glazing area. to the bodywork, thus making the light sources accessible without dismantling the glazing beforehand or destroying the encapsulation. Moving the light sources not only facilitates access to them but also increases the space available for their integration, thus allowing greater design freedom (thermal management, use of higher performance components, etc.). ). The light sources can then also be positioned in an area not subject to the direct external environment (humidity, water, dust, etc.), especially on the inside of the vehicle.

Moving the light sources out of the encapsulation zone, however, requires the transport of the light emitted from the light source to the edge of the glazing.

An ideal waveguide for this function should

be robust, compact and mechanically resistant to withstand the mechanical stresses at the encapsulation area of the glazing,

have a sufficient thermal resistance to withstand the encapsulation temperatures and / or the temperatures of use, in particular under strong sunlight,

transport the light by minimizing the light loss by diffusion and / or absorption,

Can be securely attached to the glazing to ensure good optical coupling between the light exit face of the waveguide and the edge of the glass sheet, and finally

it should be able to receive and carry the light of a large number of light-emitting diodes to ensure a significant lighting power.

The light guide developed by the Applicant and used in the present invention meets all the above requirements and has thus enabled the Applicant to propose a vehicle glazing, illuminated by light sources, preferably light emitting diodes, replaceable without destruction of the encapsulation or disassembly of the glazing. The illuminating glazing unit of the present invention has a compact and robust structure with a small footprint at the encapsulation / fixing areas and can in principle be used as a replacement for any conventional vehicle glazing, illuminating or not.

The present invention therefore relates to an illuminating vehicle glazing comprising A first sheet, made of mineral or organic glass, with a first main face, a second main face and a slice,

• at least one waveguide with

at least one first light-input end face, at least one second light-output end face facing the edge of the first sheet,

a first main guide face,

a second main guide face, and

a light return face connecting the second main guide face to the second light output end face, and designed to modify the main direction of light propagation by at least an angle equal to 90 °, preferably at an angle of about 180 ° C, and

One or more light sources each having an emitting face opposite the input end face of the light of the waveguide

One or more elements for extracting light, and

At least one encapsulation element.

The invention also relates to a vehicle comprising at least one illuminating glazing unit as defined above.

The glazing of the present invention may be used in all kinds of vehicles, such as airplanes, trains, boats, trucks and motor vehicles, replacing the glazing usually used in these vehicles. The waveguide used in the present invention and described in detail below has indeed a small footprint and thus allows the glazing container to comply with all kinds of shape constraints related to the body of the vehicle.

In a preferred embodiment, the glazing according to the present invention is an automotive glazing and in particular a side glazing or is part of a car roof.

The first glass sheet into which the light will be injected and which may be extracted may be of any glass-transparent material sufficiently transparent to allow the propagation of visible light from the injection wafer to the extraction site. . This first sheet may be part of a multi-layer glazing, for example a laminated glazing unit, or laminated glazing unit, comprising two glass sheets bonded to one another by means of an interlayer film, for example made of polyvinyl butyral (PVB). This glazing can be flat or curved.

The first sheet is preferably made of a colorless, i.e., untinted, material having a visible light transmittance (VLT) of at least 80%, preferably at least 90%, and at least 91%. These include for example the non-tinted mineral glass SGG Planilux ^®, Diamond ^® SGG Albarino and SGG ^® company Saint-Gobain Glass or plastic lenses polycarbonate (eg, polycarbonate Makrolon ^® range of Bayer), poly (methyl methacrylate), ionomeric resin, polyolefin.

In the glazing unit of the present invention, the waveguide is located in close proximity to an edge of the first sheet, so that the light exit face faces the edge of the first sheet in which the light will be injected.

The optical coupling between the exit face of the light of the waveguide and the edge of the first sheet can be done in any known manner, for example by an air knife, a convergent lens (collimator) or by means of a transparent glue. The use of a transparent glue is particularly useful when the junction between the waveguide and the first sheet is likely to come into contact with the encapsulating material. The transparent adhesive then makes it possible to prevent this junction being filled by the opaque encapsulation material.

The waveguide has two main parts:

a first flat portion defined between the first main guiding face and the second main guiding face, and

- a second part, located at the end of the first part, and whose main function is to deflect the light by an angle of at least 90 °, generally close to an angle of 180 °, before the inject into the slice of the first leaf. The first portion of the waveguide preferably has a constant thickness, that is, the first main guide face is preferably substantially parallel to the second main guide face. Although it is not an essential technical feature of the present invention and that these two faces could for example converge towards the end in contact with the second part of the waveguide, there is generally no no particular advantage associated with the use of a waveguide where this first part has an increasing or decreasing thickness.

These two main guide faces and the return face are preferably very smooth surfaces, the absence of roughness to avoid or, at least, to reduce the loss of brightness by light scattering.

The light deflection function of the second part of the waveguide is fulfilled by what is called in the present application the "return" face.

This return face may have at least one curved portion or it may comprise a set of facets. When it has two facets this return face operates in the manner of a periscope. The number of facets composing the return face is in principle not limited and a combination of a large number of facets operates in a known manner as a curved face.

When the return face comprises a curved face or is a curved face, the radius of curvature defining this curved face is preferably constant and then defines for example a quarter circle or a semicircle. The radius of curvature is also substantially equal to the thickness of the first portion of the waveguide, defined between the first and second main guide faces.

In an advantageous embodiment, illustrated hereinafter with reference to the drawings, the deflection face may further comprise a flat portion, located between the curved portion and the light output end face. This flat part is mainly intended to allow the second part of the waveguide to be supported for example on a second glass sheet of a multi-layer glazing extending beyond the first sheet of glass, either directly or via a layer of encapsulating material as shown in Figures 1 - 3.

The extent of this flat portion of the return face should however be relatively limited so as not to unnecessarily lengthen the distance traveled by the light inside the waveguide.

In one embodiment, the illuminating glazing unit of the present invention further comprises a second sheet, made of organic or mineral glass, adhered to the first sheet, for example by means of an interlayer film. This second sheet preferably has larger dimensions than the first sheet. At its near edge of the waveguide, attached to the first sheet, it preferably extends beyond the deflection face of the waveguide.

This second sheet of glass, unlike the first, may be stained glass or diffusing glass.

The use of a waveguide reduces in a known manner the overall light output of the lighting system. Indeed, with respect to a direct injection of light from the emitting surface of the light source into the edge of the first sheet, as described in WO2006 / 128941 and WO2011 / 092419, the path traveled by the light is elongated and this is not only reflected by the walls of the waveguide but is inevitably absorbed and diffused by the waveguide material, the faces thereof and the materials in contact therewith.

Various measures make it possible to reduce the diffusion and absorption of the light emitted by the light sources and thus to limit the overall loss of luminous intensity due to the use of a waveguide.

A first step is to limit as much as possible the path traveled by the light in the waveguide. For this, the first portion of the waveguide, defined between the two main guide surfaces, is preferably just long enough to deport the light entry face outside the encapsulation or fixing area of the glazing. A second measure is to choose for the waveguide a material, usually an organic polymer, having the greatest possible transparency (VLT, visible light transmission) so as to limit the light loss by absorption.

A third measure is to use a waveguide with the smoothest possible surfaces to limit the light loss by diffusion.

Finally, a fourth measure consists in covering at least a portion of the main guide faces and / or the return face of a reflective layer, generally a metal layer, for example silver or aluminum.

The Applicant has encountered a certain difficulty in firmly fixing the waveguide to the glazing unit, in particular to the first sheet on which it bears on the first main guide face, without, however, increasing the light loss due to the contact between these two materials. having a similar refractive index, close to 1.5. A reflective layer, for example a metal layer, separating the first main face of the sheet from the first main guide face of the waveguide certainly solves this problem, but generally weakens the mechanical link. Another possibility is to insert between the first main face of the first sheet and the first main guide face of the waveguide a low refractive index layer. The term "low refractive index" refers to a layer of an organic or inorganic material having a refractive index of at least 0.1 units less than the refractive index of the waveguide material. with whom she is in contact. The difference in refractive index is preferably at least 0.2 units and even more preferably at least 0.3 units.

This low refractive index layer may be, for example, a low refractive index glue layer.

The thickness of the low-reflection layer is preferably at least 1 micron, more preferably at least 5 microns. The low refractive index layer is advantageously a layer of air. Indeed, the air has a refractive index equal to 1, that is to say less than that of solid materials.

When the low refractive index layer is an air layer, spacers are advantageously used, illustrated hereinafter in FIG. 3, to maintain a certain distance between the two surfaces and thus guarantee a sufficient thickness for the layer of air. air, preferably at least 10 microns, more preferably between 50 and 500 microns, ideally between 100 and 300 microns,

It is also possible to fix the waveguide by bonding the first main guiding surface to the first main face of the sheet by means of a multi-point or multi-line bonding.

As already explained above, the solid attachment of the waveguide to the glazing, without excessive reduction of the light output due to the absorption of light by materials in contact with the waveguide downstream of the surface of the glass. entry of light, has been a particular technical problem of the present invention.

An original solution to this problem is to give the first part of the waveguide, that is to say the one defined between the two main guide faces, a crenellated form with a plurality of end faces of light entry located at the vertices of the projecting parts of the crenellations and / or in the recesses between the projections. This embodiment is illustrated in Figures 4 and 5 attached.

The emitting faces of the light sources can then be opposite the light input end faces located in the recesses between the projecting parts or facing the light input end faces at the vertices of the parts. prominent. Of course, it is advantageous to place light sources opposite these two types of end faces, that is to say both in the hollows between the projecting parts and the tops thereof.

This embodiment thus allows "to advance" a portion of the input end face of the light, namely that (s) which is then in the recesses between the projecting portions. This "advanced" position of the input end surfaces of the light has the first effect technique interesting a shortening of the optical path to travel through the light emitted by light sources located opposite the end faces in the hollows.

A second technical effect resulting from the "advancement" of at least a portion of the light sources, is the possibility of fixing the waveguide to the glazing by the projecting parts or at the level of the gaps left between the projecting parts. Such a fixation will thus be back, "in the back" light sources located in the hollows and does not risk disturbing the propagation of light in the waveguide.

In a particularly preferred embodiment of the illuminating glazing unit of the present invention, the emitting faces of the light sources are therefore situated facing the end faces of the entrance of the light in the recesses between the projecting parts and the waveguide. is fixed to the first sheet and / or the body of the vehicle at the projecting parts of the crenellations. This embodiment will be illustrated in the accompanying drawings.

The illuminating glazing of the present invention further advantageously comprises, at its edges, an encapsulating element, generally consisting of an opaque material. This encapsulation element naturally does not occupy the light sources placed opposite the light input end face, or the plurality of light input end faces. In other words, at least a portion of the light sources must be located outside the encapsulation element and be accessible for replacement in case of failure. Although the illuminating glazing of the present invention preferably does not include any non-accessible light source, this is only a preferred embodiment, and the protection of the present invention also extends to glazings in which some fraction of the light sources, preferably less than 50%, are encapsulated.

In an advantageous embodiment, the encapsulating element is in contact with at least the second main guiding face and with the reflecting surface of the light of the waveguide. Of Preferably, it is further in contact with the first glass sheet and, if appropriate, with the second glass sheet of the glazing.

The encapsulating element may be any encapsulating material usually used for this purpose, for example in the automotive industry. It is preferably a crosslinked polyurethane obtained by injection molding (Reaction injection molding, RIM). This material has the advantage of not requiring injection pressures and excessively high reaction temperatures, thereby preserving the integrity and optical quality of the organic polymer waveguide.

The waveguide used in the present invention generally consists of a transparent organic glass, that is to say a transparent organic polymer. This polymer may in principle be any thermoplastic or thermoset polymer having a low linear absorption coefficient, preferably less than 10 ^-3 mm ^-1 , more preferably less than 10 ^-4 mm ^-1 . This polymer must also have good thermal resistance in the case where the glazing during manufacture is exposed to high temperatures, for example during the encapsulation step. Finally, it must not be excessively fragile and must have a certain aptitude for elastic and / or plastic deformation, preferably elastic, to be able to withstand the possible mechanical stresses to which it will be subjected once fixed to the glazing.

Nonlimiting examples of organic polymers that may be suitable as waveguide materials include poly (methyl methacrylate) (PMMA), thermoplastic or thermoset polycarbonates (PC), or copolymers of cycloolefins (COC).

Polycarbonate is particularly preferred because it combines a satisfactory transparency (VLT of 88%) with a good thermal resistance (Tg 150 ° C.).

However, when the glazing is not part of a car roof and encapsulation does not involve heating beyond a temperature at 80 ° C, PMMA is the best choice because of its high transparency.

The light sources used in the illuminating glazing of the present invention are preferably light emitting diodes (LEDs). In principle, any type of LED can be used inasmuch as it is sufficiently powerful and miniaturized to be able to be placed facing the input end face of the light of the waveguide.

The waveguide, thanks to its elongated shape and in particular due to the rather large extent of the light entry face, makes it possible, unlike an optical fiber for example, to carry the light of a large number of light sources placed opposite the light entry face.

In the illuminating glazing of the present invention, a large number of LEDs, for example at least three, preferably at least five and more preferably at least ten LEDs, are placed facing the light entry face or faces of the light guide. 'wave. These LEDs are arranged along the light entry end face over a length covering at least 50%, preferably at least 70% of the length of the end face.

Although light sources are an essential technical feature of the illuminating glazing of the present invention, it is important to note that these light sources are not necessarily mounted on the glazing itself. They indeed perform their function, interacting with the waveguide, in a perfectly equivalent manner when they are fixed on the vehicle body in a position facing their emitting faces with the input face of the guide light wave.

The waveguide preferably has dimensions relatively small compared to the dimensions of the illuminating glazing. It is indeed to design the waveguide with a minimum size, but sufficient to be able to deport the light sources outside the encapsulation area and / or mounting of the glazing. The dimension of the waveguide to be optimized is its length, that is to say the guide distance from the light input end face to the beginning of the face of the light. reference.

This length of the waveguide is preferably at most equal to 20%, in particular at most equal to 10% of the smallest dimension of the first sheet of the glazing.

On the other hand, the width of the waveguide, corresponding to the length of the input end face of the light, is not particularly limited if not by the dimension of the edge of the glazing at which the waveguide must be fixed.

Finally, the illuminating vehicle glazing of the present invention further comprises one or more light extraction elements. These elements are preferably applied to at least one of the main faces of the first sheet, preferably on the first major face of the first sheet, intended to be turned towards the inside of the vehicle. These extraction elements are formed by a thin diffusing layer formed of particles having a mean size of between about 50 nm and 1 μηη, these particles being fixed on the support by means of a mineral or organic binder.

The particles may be inorganic particles, for example based on oxides, carbides or metal nitrides. Examples of preferred particles include particles of silica, alumina, zirconia, titanium oxide and cerium oxide.

Such diffusing layers are described for example in the international application WO01 / 90787.

The present invention is now described in more detail with reference to the accompanying figures in which

FIG. 1 is a cross section of a waveguide according to the invention placed at the edge of a laminated and encapsulated glazing unit

FIGS. 2 and 3 are cross-sections of two embodiments of a waveguide according to the invention,

FIGS. 4 and 5 are views from above of a waveguide according to the invention having a crenellated form, and Figure 6 is a partial perspective view of an illuminating glazing according to the invention, showing the constituent elements in transparency.

Figure 1 shows, more particularly, the edge of a laminated glazing unit with a first glass sheet 1 and a second glass sheet 4, glued to each other by means of a spacer sheet 5. The first sheet of glass 1 has a first main face 11, a second main face 12 and a wafer 13. The waveguide 2 has a first end face 21 of entry of the light, a second end face 22 of exit light, a first main face 23 for guiding the light, a second main face 24 for guiding the light, and a return face 25 of the light. The first end face 21 receives the light emitted by the emitting face 31 of a light source 3, in this case a light-emitting diode, placed opposite the first end face 21 of the waveguide 2. The light input through the input face 21 of the waveguide is guided, in a first portion of the waveguide, by the first and second main guide faces 23, 24, to a second portion of the waveguide. wave, bounded by the deflection face 25. The return face comprises a curved portion having a constant radius of curvature r, substantially equal to the thickness of the first portion of the waveguide defined between the first and second main faces 23, 24. The deflection face further comprises a flat portion 26, connecting the curved portion to the second end face 22 of the output of the light. The second exit end face 22 of the light is located opposite the wafer 13 of the first glass sheet. The optical coupling between these two surfaces is provided by a transparent adhesive seal 27 which has the dual function of fixing the waveguide to the first sheet and preventing the junction between the faces 13 and 22 from being filled by the opaque material of the encapsulation element 6 overmolded after placement of the waveguide 2.

FIG. 2 shows an embodiment of the glazing unit of the present invention which differs from that shown in FIG. 1 only by the presence of a reflective layer 32 covering the first face main guide 23, the second main guide face 24, and the deflection face 25. As explained above, this layer has the main function of limiting or even eliminating light losses due to the refraction of light at the level of the waveguide surface and the absorption of light by the materials in contact with the guide surfaces 23, 24, 25 of the waveguide, i.e. the coating 6 and the first sheet of glass 1.

FIG. 3 shows another embodiment, similar to that of FIG. 2, but where the reflective layer 32 is present only at the level of the second main guiding face 24 and of the deflection face 25. At the level of the first main guiding face 23, it is replaced by an air layer 33. The thickness of this air layer 33, that is to say the spacing between the first main guide face 23 of the guide of wave and the first main face 11 of the first glass sheet 1, is determined and provided by spacers 34 which may also have a function of fixing the waveguide glazing.

FIG. 4 illustrates an embodiment of the glazing unit according to the present invention in which the first flat part of the waveguide has a "crenellated" shape, with projecting portions 29, here five in number. Slot cutting results in the creation of a plurality of input end faces of light at the apices 28a of the projecting portions 29 and in the recesses 28b between the protruding portions. Three light-emitting diodes 3 are placed in each of the four cavities between the five projecting portions 29, their emitting face 31 being opposite to the input end faces 28b of the light. The projections 29 are covered in part by an adhesive 35 for attaching the waveguide 2 to the vehicle body (not shown).

The embodiment shown in FIG. 5 differs from that of FIG. 4 mainly in that light sources 3 are placed at the vertices 28a of the projecting parts. An adhesive tape 36 extends parallel to the edge of the first glass sheet 1 on all the projections 29. It fixes the waveguide 2 to the first glass sheet 1 and / or the body of the glass. vehicle (not shown). Finally, FIG. 6 shows a general partial perspective view of the illuminating glazing unit of the present invention, with its main elements being the first glass sheet 1, the second glass sheet 4 of larger size than the first sheet of glass. 1 and glued to it by means of an interlayer film (not shown). The first flat part of the waveguide 2, between the main guide faces 23, 24, bears against the first glass sheet 1, while the return face 25 bears, with its flat part 26, on the second sheet of glass 4 in the part where it extends beyond the first sheet of glass. The encapsulation element 6 partially coats the waveguide 2 and the second glass sheet 4. The light-emitting diodes 3, on the other hand, are not covered by the encapsulation 6 and thus remain accessible for a possible replacement. They are advantageously covered with a cover or a removable cover (not shown)

Finally, a light extracting element 37 is applied to the first major face of the first sheet 1 and will diffuse the light extracted from the first sheet of glass towards the interior of the vehicle.

Claims

1. Glazing vehicle window, comprising

a first sheet (1) made of mineral or organic glass with a first main face (11), a second main face (12) and a wafer (13),

at least one waveguide (2) with

at least one first end face (21) for entering the light,

at least one second exit end face (22) facing the edge (13) of the first sheet (1),

a first main guide face (23),

a second main guide face (24), and

a deflection face (25) of the light connecting the second main guiding face (24) to the second exit end face (22) of the light, and designed so as to modify the main direction of propagation of the light; light at an angle of at least 90 °, and

one or more light sources (3) each having an emitter face (31) facing the light input end face (21), one or more light extraction elements (37), and

at least one encapsulation element (6).

2. illuminating vehicle window according to claim 1, characterized in that the first main guide face (23) is substantially parallel to the second main guide face (24).

Illuminating vehicle glazing according to claim 1 or 2, characterized in that the deflection face (25) is designed to change the main direction of propagation of the light by an angle of about 180 °.

4. illuminating vehicle glazing according to claim 3, characterized in that the return face (25) of the light comprises at least one curved portion or a set of facets.

5. illuminating vehicle glazing according to any one of the preceding claims, characterized in that the first main guide face (23) of the waveguide is separated from the first main face (11) of the first sheet (1) by a reflective layer, preferably a metal layer, or a low refractive index layer of an organic or inorganic material having a refractive index of at least 0, 1 unit at the refractive index of the material forming the waveguide.

Illuminating vehicle glazing according to claim 5, characterized in that the low refractive index layer is an air layer.

Illuminating vehicle glazing according to one of the preceding claims, characterized in that at least a portion of the main guide faces (23, 24) and / or the deflection face (25) is covered with a layer reflective material (32), preferably a metal layer.

Illuminating vehicle glazing according to one of the preceding claims, characterized in that the portion of the waveguide defined by the first and second guide faces (23, 24) has a crenellated form with a plurality of light-entry end at the peaks (28a) of the projecting portions (29) and / or in the recesses (28b) between the projecting portions.

Glazing vehicle glazing according to claim 8, characterized in that the emitting faces of the light sources are opposite the input end faces of the light at the vertices (28a) or facing the input end faces light in the recesses (28b), or opposite these two types of end faces (28a, 28b).

Illuminating vehicle glazing according to claim 9, characterized in that the emitting faces of the light sources are located facing the entrance end faces of the light in the recesses (28b) and the waveguide is fixed to the first sheet (1) and / or the vehicle body (30) at the projecting portions (29) of the crenellations.

Glazing vehicle glazing according to any one of the preceding claims, characterized in that it further comprises a second sheet (4) made of organic or mineral glass, adhered to the first sheet (1) by means of a film interlayer (5), the second sheet (4) extending preferably beyond the deflection surface (25) of the light. Illuminating vehicle glazing according to claim 11, characterized in that the encapsulating element (6) is in contact with at least the second main guide face (24) and the light return surface (25). , and possibly also with the first sheet (1). Illuminating vehicle glazing according to any one of the preceding claims, characterized in that the deflection face (25) of the light is a curved surface or has a curved surface having a radius of curvature substantially equal to the thickness of the guide wave (2). Illuminating vehicle glazing according to any one of the preceding claims, characterized in that the light sources are not fixed on the illuminating glazing itself.

Vehicle comprising at least one illuminating glazing unit according to any one of the preceding claims.