Luminois laminated glazing with enhanced solar and ambient light performance

Abstract

A laminated luminescent glazing with superior solar control and ambient lighting capability comprising at least two glass layers (201, 202), at least one plastic bonding layer (4), a lighting means (12), a light coupling means (14), a light decoupling means (16), a light conductive layer (40), and a darkening means (30). The darkening means (30) comprising: a dark solar control coating (42), a functional film (22), a dark plastic bonding layer separated from the light conductive layer (40) by a layer of clear plastic bonding layer (4) or any combination of.

Description

[0001] LUMINOIS LAMINATED GLAZING WITH ENHANCED SOLAR AND AMBIENT LIGHT PERFORMANCE

[0002] FIELD OF THE INVENTION

[0003] This disclosure relates to the field of automotive laminated glazing and, specifically, to luminous laminated automotive roof glazing with enhanced solar control and ambient lighting capability.

[0004] BACKGROUND OF THE INVENTION

[0005] Over the last decade, large automotive panoramic sunroofs have become a popular and fastgrowing option on new vehicles. One of the challenges of integrating large roof glazing has been providing ambient cabin lighting. A recent development takes advantage of the optical principle of total internal reflection, TIR, to provide ambient lighting. A lighting means is optically coupled to the glazing. The light is injected into the glazing where it is trapped by TIR. The transparent layers of the laminate serve as a light conductive layer, in the same manner that an optical fiber does. The light conductive layer must be made from a glass composition with high visible light transmission. A light decoupling means, applied to the light conductive layer, allows the light to exit the glazing. The resulting luminescent ambient lighting gives the glazing a very desirable, high tech and futuristic look and feel.

[0006] Another challenge is that with their large surface area, the load on the air conditioning of the vehicle can increase due to the solar energy entering the cabin. Therefore, a solar control means is often required.

[0007] One of the most effective solar control means is a coating, tuned to reflect in the infrared while transmitting in the visible. One drawback to such coatings is that they are fragile and not suitable for use on exposed surfaces. They must be applied to one of the inner surfaces 102, 103 of a laminate. It is also important to minimize the energy absorbed by the layers between the coating and the vehicle outer major surface 101 of the glazing. For maximum efficiency, a highly transparent glass composition must be used.

[0008] While highly effective automotive solar control coatings are known that can block better than 60% of the total solar energy (across the entire spectrum), these same coatings are designed to have a level of visible light transmission (VLT) of at least 70% so as to comply with regulatory requirements for windshields. Most automotive coaters were designed for and configured for this type of coating only. There has been little motivation to develop and to upgrade equipment to produce darker coating as tinted glass compositions and tinted plastic bonding layer are readily available and inexpensive. As a result, standard automotive coatings alone cannot lower the VLT to the range required. As tinted glass compositions cannot be used for a luminescent solar control laminate, the typical solution has been a dark tinted plastic bonding layer. Another challenge results from losses in the light conductive layer. The lighting means intensity must be increased to overcome losses. This can result in thermal management issues. It would be highly desirable to improve the efficiency of such glazing.

[0009] BRIEF SUMMARY OF THE INVENTION

[0010] The glazing of this disclosure is a luminous laminated glazing with enhanced solar and ambient light performance as illustrated in the generic cross section of Figure 1. The laminate comprises a first glass layer having an outer major surface, surface one, and an inner major surface, surface two, wherein the outer major surface is opposite to the inner major surface , and the first glass layer has an edge surface; a second glass layer, having an inner major surface, surface three, and an outer major surface, surface four, wherein the outer major surface is opposite to the inner major surface and the second glass layer has an edge surface; at least one plastic bonding layer arranged between the inner major surface of the first glass layer and the inner major surface of the second glass layer; a darkening means arranged between the inner major surface of the first glass layer and the at least one plastic bonding layer; a solar control means; a light conductive layer; and at least one lighting means configured to couple its light into the light conductive layer; wherein the second glass layer is the light conductive layer and wherein the solar control means is the darkening means or is arranged between the first glass layer and the darkening means or is the darkening means.

[0011] The darkening means 30 is selected from the group comprising a functional film 22, a dark polymeric film 2, a dark solar control coating 42, or any combination thereof.

[0012] Surprisingly, the intensity of the emitted light is increased over the same glazing with a dark tinted plastic bonding layer directly laminated to the light conductive layer.

[0013] BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0014] Figure 1 is a generic cross section of the panoramic laminated luminescent glazing of the disclosure having a darkening means.

[0015] Figure 2A is an exploded isometric view of a panoramic laminated luminescent roof with a dark solar control coating darkening means.

[0016] Figure 2B is an exploded isometric view of a panoramic laminated luminescent roof with a darkening means comprising a dark polymeric film. Figure 3A is an exploded isometric view of a panoramic laminated luminescent roof with a functional film darkening means.

[0017] Figure 3B is a top view of the panoramic laminated luminescent roof of Figures 2A, 2B and 3A.

[0018] Figure 4A shows Section XX of the panoramic laminated luminescent roof with a dark solar control coating darkening means of illustrated in Figure 2A.

[0019] Figure 4B shows Section XX of the panoramic laminated luminescent roof with a darkening means comprising a dark polymeric film illustrated in Figure 2B.

[0020] Figure 5A shows Section XX of the panoramic laminated luminescent roof with a functional film darkening means illustrated Figure 2A.

[0021] Figure 5B shows Section XX of a panoramic laminated luminescent roof with a dark solar control coating, functional film, dark polymeric film darkening means and a clear plastic bonding.

[0022] REFERENCE NUMERALS OF DRAWINGS

[0023] 2 Dark polymeric film

[0024] 4 Clear plastic bonding layer (interlayer)

[0025] 6 Obscuration / Black Paint

[0026] 12 Lighting means

[0027] 14 Light coupling means

[0028] 15 Light source

[0029] 16 Light decoupling means

[0030] 18 Additional coating

[0031] 20 Solar control means. 22 Functional film / switchable film

[0032] 24 Light bar

[0033] 30 Darkening means

[0034] 40 Light conductive layer

[0035] 41 Standard solar control coating

[0036] 42 Dark solar control coating

[0037] 91 Edge surface of first glass layer

[0038] 92 Edge surface of second glass layer

[0039] 101 Outer side of first glass layer 201 , surface one.

[0040] 102 Inner side of first glass layer 201 , surface two.

[0041] 103 Inner side of second glass layer 202, surface three.

[0042] 104 Outer side of second glass layer 202, surface four.

[0043] 200 Luminous laminated glazing

[0044] 201 First glass layer

[0045] 202 Second glass layer

[0046] DETAILED DESCRIPTION OF THE INVENTION

[0047] The present disclosure can be understood by reference to the detailed descriptions, drawings, examples, and claims, of this disclosure. However, it is to be understood that this disclosure is not limited to the specific compositions, articles, devices, and methods disclosed unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing aspects only and is not intended to be limiting. The focus of the embodiments and discussion is on an automotive roof laminate where the glazing of the disclosure is of particular advantage. However, this shall not be taken as a limitation. Embodiments of the disclosure may include any of the vehicle glazing positions and glazing of any size as well as flat or curved glazing. In addition, the immediate invention may be used in any glazing application including architectural and vehicles other than automotive.

[0048] The following terminology is used to describe the laminated glazing of the invention.

[0049] A glazing is an article comprised of at least one layer of a transparent material which serves to provide for the transmission of light and / or to provide for viewing of the side opposite the viewer and which is mounted in an opening in a building, vehicle, wall or roof or other framing member or enclosure.

[0050] The structure of the invention is described in terms of the layers comprising the glazing. The meaning of “layer,” as used in this context, shall include the common definition of the word: a sheet, quantity, or thickness, of material, typically of some homogeneous substance and one of several. The thickness of each layer is uniform and much less than the length and width of the layer. Each layer has two major surfaces and an edge. The two major surfaces of each layer are parallel and opposite to each other.

[0051] Unless otherwise stated in the description, all figures are to be considered as for illustrative purposes and are not drawn to scale and thus shall not be construed as a limitation.

[0052] Laminates, in general, are articles comprised of multiple layers of thin, relative to their length and width, material, with each thin layer having two oppositely disposed major faces, typically of uniform thickness, which are permanently bonded to one and other across at least one major face of each layer. The layers of a laminate may alternately be described as sheets or plies. In addition, the glass layers may also be referred to as panes.

[0053] Safety glass is glass that conforms to all applicable industry and government regulatory safety requirements for the application. Laminated automotive safety glass is made by bonding two glass layers, a first glass layer 201 and a second glass layer 202 together using at least one plastic bonding layer 4 comprised of a thin sheet of transparent thermoplastic 4 (interlayer). The first glass layer 201 has an outer major surface 101 , surface one, and an inner major surface 102, surface two, wherein the outer major surface 101 is opposite to the inner major surface 102, and the first glass layer has an edge surface 91. The second glass layer 202 has an inner major surface 103 and an outer major surface 104, surface four, wherein the outer major surface 104 is opposite to the inner major surface 103 and the second glass layer has an edge surface 92. The inner major surface of the first glass layer is arranged facing the inner major surface of the second glass layer. At least one plastic bonding layer 4 is arranged between the inner major surface 102 of the first glass layer 201 and the inner major surface 103 of the second glass layer 202. A process utilizing vacuum, heat and pressure is used to permanently bond the glass and plastic layers together. An obscuration 6 may also be applied to the glass.

[0054] In an embodiment, in an operating position of the glazing, with the glazing mounted as part of a vehicle, the outer major surface of the first glass layer is the surface of the glazing facing the exterior of the vehicle and the outer major surface of the second glass layer is the surface of the glazing facing the interior of the vehicle.

[0055] The laminated glazing may be flat or formed to a curved shape. The glass layers may be formed by any appropriate thermal process. In addition to thermal forming, one or more glass layer may be cold formed. Each glass layer may be annealed, partially heat strengthened, heat strengthened to full temper or chemically tempered.

[0056] The glass layers may have coatings applied. Methods of application include Magnetron Sputtered Vacuum Deposition (MSVD) as well as others known in the art that are applied via pyrolytic, spray, controlled vapor deposition (CVD), dip, sol-gel, and other methods.

[0057] On large glazing, a solar control means 20 is needed. A solar control means is any means method that limits the quantity of solar energy entering the vehicle passenger compartment. Solar control means are typically solar control coatings and are usually applied to the first glass layer 201 . In the context of this disclosure, standard solar control coatings are known in the state of the art, and typically comprise at least one silver inclusive layer. For example, a glass layer having a standard solar control coating deposited may have a VLT of at least 70%. In an embodiment of the invention, the solar control means are a solar control coating layer deposited onto the inner major surface of the first glass layer.

[0058] In an embodiment, the solar control means can also be selected from the group comprising an additional film having solar control properties and a solar control coating deposited onto the substrates of a switchable film

[0059] A variety of coatings are used for the second glass layer 202, particularly the inner major surface 104. These coatings 18 include but are not limited to low-E, anti-reflective, antifingerprint, or any combination thereof. Low-e can turn the interior of the vehicle into a greenhouse by trapping heat inside the vehicle, but, when a low-e coating is used in conjunction with a solar control coating, much of the solar energy is rejected which eliminates the green-house effect. This combination has proved useful in panoramic glass roofs. In cold weather, there is a tendency for occupants to become uncomfortably cold due to the cold uninsulated glass surface just a short distance from the tops of their heads. Low-e coating have been found to eliminate consumer complaints in this area.

[0060] Anti-reflective coatings have seen increased use in roof applications considering that the reflection of the roof may be distracting with all of the electronics in the instrument panel and mounted elsewhere as well as devices that passengers may be using.

[0061] An anti-fingerprint coating is desirable since fingerprints on the glass, with the decoupled light backlighting them, are more noticeable. In preferred embodiments, coatings that combine two or more of these three desired functionalities are included in the invention.

[0062] Obscurations 6 are commonly used on glazing, to hide the mounting adhesive and other features, and may be a black enamel frit printed or an insert. When included the obscuration is printed on either surface two 102 of the first glass layer 201 , surface four surface 104 of the second glass layer 202 or on both. Obscurations can be printed on top of other coatings, such as the solar control coatings, therefore a solar control coating 41 , 42 may be printed between the glass surface 102, 104 and the obscuration 6. The obstruction needs to be opaque in the sense of difficulty to see through rather than blocking all light. The typical light transmission is less than 5% and preferably less than 3% and more preferably still equal to 0%.

[0063] The plastic bonding layer 4, (interlayer) has the primary function of bonding the major faces of adjacent layers to each other. The material selected is typically a clear thermoset plastic. For automotive use, the most used bonding layer 4 (interlayer) is polyvinyl butyral (PVB). In addition to polyvinyl butyral, ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), polyolefin elastomers (PoE), polyethylene terephthalate (PET), optical adhesive resins (OCR), liquid optically clear adhesives (LOCA) or any combination thereof may be used.

[0064] Preferably, the thickness of the plastic bonding layer is comprised between 0.3 mm and 2.0 mm, such as between 0.5 mm and 1.0 mm, e.g., about 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm. Particular thicknesses for the plastic bonding layer are for instance 0.38 mm, 0.631 mm, and 0.76 mm The types of glass that may be used also include but are not limited to aluminosilicate, lithium aluminosilicate, borosilicate, glass ceramics, and the various other inorganic solid amorphous compositions which undergo a glass transition and are classified as glass.

[0065] Preferably, the thickness of the first 201 and second 202 glass layer may vary widely and thus be ideally adapted to the requirements of the individual cases. In an embodiment, the thickness of each glass layer of the glazing of the invention comprised between 0.5 mm and 4 mm, preferably the first glass layer 201 having a thickness between 1.6 to 4 mm and the second glass layer 202 having a thickness from 0.5 to 3.2 mm. More preferably, the first glass layer has a thickness of about 2.1 mm and the second glass layer has a thickness of about 2.1 mm. In an additional embodiment, the glazing may include additional glass layers between the first and second glass layer.

[0066] Preferably, in one embodiment the laminated glazing of the invention has a total visible light transmission from 0 to 25 %, preferably from 0 to 14%, more preferably from 4 to 10%. Clear glass is considered as one that has a VLT of at least 86%. There is also what is known as an ultra-clear glass which has a VLT of at least 89%. In another preferred embodiment the first glass layer 201 has a total visible light transmission of at least 80%, preferably of at least 86%, more preferably of at least 89%. In another preferred embodiment the second glass layer 202 has a total visible light transmission of at least 86%, preferably of at least 89%. Having clear and ultra clear glasses provides advantages when the curving of the glasses is performed.

[0067] VLT is calculated using a specialized measurement tool. A light source is placed on one side of the glazing and a photodetector on the other side. The amount of visible light passing through is measured. The value is typically expressed as a percentage. The higher the number the more visible light is able to pass through. Various instruments are sold that may be used to measure VLT provided that they conform to the standard ISO 9050 (2003).

[0068] The Lighting means 12 is any means that at a minimum is capable of producing the intensity of illumination required, in the desired frequency band, and that can be successfully packaged. The lighting means 12 comprises a light source 15. In one embodiment, the light source is at least an array of LEDs and is sometimes called a light bar 24. The LEDs are packed in an assembly 24 which is mounted such that the light is injected into the light conductive layer. The lighting components of the lighting means 12 may be disposed on a flexible printed circuit, a printed circuit board (PCB) and / or a semi-flexible PCB. In an embodiment, the light emitted from the lighting means 12 is coupled into an edge surface. The light may be injected into an edge 92 as illustrated in Figures 4A, 4B, 5A and 5B of the light conductive layer 202, 40, therefore the light conductive layer 40 is the second glass layer 202. The light bar 24 may be coupled in any edge of the glazing. In an embodiment, the first and second glass layer have substantially the same size when both are cured in the final position. In another embodiment, at least a part of the edge of the first glass layer is recessed relative to the edge of the second glass layer after being laminated together. In yet another embodiment, at least a part of the edge of the second glass layer is recessed relative to the edge of the first glass layer after being laminated together.

[0069] In another embodiment, the light emitted is coupled into a mayor surface of the second glass, particularly the light is injected into surface four 104 of the light conductive layer 202, 40 as shown in Figure 1. In some embodiments, the lighting means may be embedded within the laminate.

[0070] When multiple light bars 24 are included, they can be located in opposite sides of the glazing, in adjacent sides, in three sides, in four sides and along the perimeter of the glazing.

[0071] It should be noted that other lighting means may be used in place of the LEDs of the described embodiments and as discussed in this disclosure without departing from the concept of the invention. The lighting means 12 may include OLEDs, electro luminescent, fiber optics, light pipes and even means not yet invented.

[0072] Any frequency, band of frequencies, or combination of frequencies in the visible light range may be emitted by the lighting means 12. The light emitting components of the lighting means may comprise red, green, blue, white, LEDs (RGBW), and / or red, green, blue, LEDS (RGB), and / or single wavelength light sources and / or monochromatic light sources and / or a combination thereof.

[0073] Ordinary glazing, on which a low VLT is required, typically will make use of tinted glass compositions. However, such glass composition absorbs much of the solar energy and as a result get hot. The hot glass surface will transfer energy to the passenger compartment by reradiating and through convective transfer.

[0074] Infra-red reflecting solar control coatings are very effective as a solar control means. However, they need to be applied to highly transparent glass. Otherwise, some of the solar energy will be absorbed entering the glass and again after being reflected by the coating. So, solar coated laminates include a coating applied to surface two 102 of the first glass layer and a clear, or ultra-clear glass composition. In preferred embodiment of this invention, the solar control means 20 is a standard solar control coating 41 layer deposited onto the inner major surface 102 of the first glass layer 201.

[0075] Glazing that makes use of TIR to provides lighting requires a light conductive layer. The light conductive layer 40 also needs to be a clear or ultra-clear for the best light output. While the first glass layer could serve as a light conductive layer, the emitted decoupled light would be visible from outside of the vehicle. To have the light emitted on the vehicle interior side of the glazing, the light conductive layer is preferably the second glass layer. If more than two glass layers are used, the glass layer having a major surface adjacent to and comprising a portion of the vehicle interior is preferably used as light conductive layer 40.

[0076] The requirement to use highly transparent glass for both glass layers in the laminate limits the means used to reduce the visible light transmission to the plastic bonding layer. Dark tinted plastic boding layers are in common use and readily available. However, when used with a TIR light conductive layer, the tinted plastic bonding layer bleeds off and wastes a substantial portion of the injected light which is undesirable. This waste can be compensated by increasing the intensity of the injected light, but it presents issues. While LED light sources are much more efficient than incandescent, they still generate waste heat which must be managed. A 30% increase in intensity will have a corresponding 30% increase in heat. When LEDs are used, the LEDs are preferably mounted in a compact package and are surrounded by materials that are poor thermal conductors (plastic, adhesive, glass) thermal management can be challenging.

[0077] A means may be required to efficiently couple and inject light into the light conductive layer. The light coupling means 14 provides a path for the light from the lighting means 12 to travel through and be injected into the light conductive layer 40. A number of methods can be used to create the light coupling means 14 which include but are not limited to an index matched optical adhesive, an index matched transparent hot melt thermoplastic, and a plastic assembly. In some cases, direct coupling of the lightning means can be used without the need for coupling means.

[0078] The injected light trapped in the light conductive layer is emitted in a controlled manner. This is done by a light decoupling means 16. A light decoupling means is any means that will frustrate TIR in a light conducting layer allowing light to escape from the light conducting layer 40. This is accomplished by changing the angle of refraction to less than the critical angle or the index of refraction at the glass / air interface such that TIR no longer is possible. In one embodiment, the light decoupling means 16 is applied to the light conductive layer by a variety of methods including but not limited to a graphic printed on the glass, sandblasting, chemically etching, LASER etching; scattering particles embedded on or in an inorganic or organic matrix, glass edging, sanding, organic or inorganic enamels and plastic bonding layers with scattering particles. The light decoupling means is applied such that a graphic design appears when light is injected. In another embodiment, the light coupling means 14 may also be applied on the bonding layer or in any other the interlayer of the glazing optically compatible with the TIR. The light decoupling means is shown in the figures as a continuous layer for simplification.

[0079] When a dark tinted plastic bonding layer is used as the darkening means and is directly laminated to the light conductive layer, some of the injected light is absorbed by the dark tinted plastic bonding layer. The glazing of the disclosure does not utilize this dark tinted plastic bonding layer darkening means directly laminated to the light conductive layer i.e. a plastic bonding layer in direct contact with the light conducting layer is not a dark tinted one. Rather, the darkening means 30 is selected from a group comprising a functional film 22, a dark polymeric film 2, a dark solar control coating 42, and a combination of thereof. Such darkening means have a total visible light transmission from 0 to 60 %, preferably from 0 to 18%, more preferably from 0 to 10% according to ISO 9050 (2003). In a preferred embodiment, the darkening means is not provided by the glass layers.

[0080] In preferred embodiments, when the darkening means comprises a functional means, the total visible light transmission of the switchable films of the invention ranges from 0 to 60% and more preferably from 0 to 50% in either possible switchable state. It is measured according to ISO 9050 (2003) performing the measurement directly to the switchable films. In another embodiment, when the darkening means is a dark polymeric film 2, the total visible light transmission ranges from 0 to 18%, more preferably from 0 to 13% measured according to ISO 9050 (2003) performing the measurement to the dark polymeric layer laminated between two glass layers each of them having a VLT of at least 88%. In yet another embodiment, when the darkening means 30 is a dark solar control coating 42 the total visible light transmission ranges from O to 18%, more preferably from 0 to 10% measured according to ISO 9050 (2003), performing the measurement to the dark solar control coating 42 deposited onto the glass.

[0081] In an embodiment of the invention, the at least one plastic bonding layer is in direct contact with the light conductive layer; i.e the plastic bonding layer is in direct contact with the first major surface of the second glass layer and has a total visible light transmission of at least 80%, preferably from 80 to 90% and more preferably of at least 86% measured according to ISO 9050 (2003) performing the measurement to the plastic bonding layer laminated between two glass layers each of them having a VLT of at least 88%.

[0082] In an embodiment of the invention, a darkening means is arranged between the inner major surface of the first glass layer and the at least one plastic bonding layer.

[0083] In a first preferred embodiment the darkening means comprises functional films 22. Functional films 22 include various films, relative to the glass thickness, films that are laminated within the glazing, which provide additional functionality. The types of functional film utilized by the glazing of this disclosure are “switchable” which should be understood as a film that responds to external stimuli by changing optical, electrical and / or mechanical properties, thus providing dynamic control over light transmission. The switchable films 22 that can be employed in the context of this disclosure is not limited to, Suspended Particle Devices (SPD), Polymer Dispersed Liquid Crystal (PDLC), Polymer Network Liquid Crystal (PNLC), electrochromic (EC) films and Liquid Crystal (LC) films.

[0084] SPD goes from dark in the off state to less dark in the on state. In an SPD film, microscopic droplets of liquid containing needle like particles, light vales, are suspended in a matrix. In the off state the particles are in a random state of alignment and block the transmission of light. The degree of alignment and resulting tint can be varied in response to the applied AC voltage. The light transmittance in the on and off states can also be shifted through changes to the thickness and composition of the active material. In the off state, it is still possible to see clearly through SPD.

[0085] PDLC is a switchable light scattering technology which goes from opaque in the off state to clear in the on state. In a PDLC film, microscopic droplets of liquid crystal are suspended in a polymer matrix. In the off state the liquid crystals are in a random state of alignment and scatter the light providing privacy. In the off state, the film is substantially opaque. When an electric field is applied, the crystals align and allow light to pass. The degree of scattering can be varied by varying the amplitude of the applied voltage.

[0086] PNLC is very similar to PDLC except that the internal polymeric structure is an interconnected network instead of droplet suspension. LC is a glass or plastic cell containing liquid crystal and dyes that changes transmission when an electrical field is applied to the system.

[0087] Electrochromic switchable films comprise layers of a material that changes from dark to clear when a low direct current volage is applied to the electrodes. Reversing the electrical field polarity changes the system from clear back to dark. Switchable films 22 may be colored; these films are known as colored switchable films. The coloration may be performed by different methods known in the state of the art such as darkening of substrates, darkening of ITO, voltage modulation, cell gap change and changes to the physical-chemical properties of the active matrix. In a preferred embodiment, the darkening means is a colored switchable film, more preferably a black-PDLC. Colored switchable films are capable of providing the needed darkening, when used as darkening means, in either possible switchable state.

[0088] In a preferred embodiment, the total visible light transmission of the switchable films of the invention ranges from 0 to 60% and more preferably from 0 to 50% in either possible switchable state. It is measured according to ISO 9050 (2003) performing the measurement directly to the switchable films.

[0089] When a functional film is used as darkening means, the glazing comprises clear and / or ultraclear glasses and may include clear plastic bonding layers, a high VLT solar control means, and the switchable functional film. Particularly, the switchable film is arranged between at least two plastic bonding layers.

[0090] In a second preferred embodiment, the darkening means comprise a dark polymeric film 2 selected from PET, EVA, PVB and Pll and it is arranged between the first glass layer and the at least one plastic bonding layer. Preferably, the total visible light transmission ranges from 0 to 18%, more preferably from 0 to 13% measured according to ISO 9050 (2003) performing the measurement to the dark polymeric layer laminated between two glass layers each of them having a VLT of at least 88%. More preferably the dark polymeric film 2 is a grey PVB. In a preferred embodiment, the plastic bonding layer is in direct contact with the dark polymeric film. The clear plastic bonding layer 4 has a total visible light transmission of at least 80%, preferably from 80 to 90% and more preferably of at least 86%. When a dark polymeric film 2 is included in the configuration of the stack, the intensity of the emitted light is increased over the same glazing with a dark tinted plastic bonding layer directly laminated to the light conductive layer. This improvement effect may be confirmed by measuring either the light luminance, light leakage and / or reduction of optical effects at the edges of the glass where the light is injected, optical effects could have the shape of waves, patterns, or others. For example, the emitted light could be increased by at least 30%.

[0091] In a preferred embodiment, a switchable film is arranged between the dark polymeric film 2 and the at least one plastic bonding layer. In a more preferred embodiment, the switchable film is a colored switchable film as mentioned above. In another preferred embodiment, an additional polymeric film such as a PET film is arranged between the dark polymeric film and the at least one plastic bonding layer.

[0092] In a third preferred embodiment, the darkening means comprises a dark solar control coating 42. Solar control coatings have been made primarily for windshield applications where a VLT of at least 70% is required. Likewise, in architectural glass applications the VLT level is adjusted to admit the right portion of natural light into a building, and tinted glass is an inexpensive solution when darker glazing is desired. Thus, a suitable coating, with the required optical and aesthetic qualities was not readily available.

[0093] The dark solar control coating 42 disclosed can be tuned to have a low VLT, a high solar energy rejection, a low haze, and a neutral reflected and transmitted color at both normal and steep angles of incidence. In a preferred embodiment, when the darkening means comprises the dark solar control coating, the coating is deposited onto the inner major surface of the first glass layer

[0094] In a preferred embodiment of the invention, the darkening means 30 is a dark solar control coating 42 having a multilayer configuration. Preferably, the total visible light transmission ranges from O to 18%, more preferably from 0 to 10% measured according to ISO 9050 (2003), performing the measurement to the dark solar control coating 42 deposited onto the glass layer. In a preferred embodiment the darkening means 30 is the solar control means 20. The coating has the following layer configuration, the layers are listed in the order that they are deposited on the glass:

[0095] • an optional barrier layer serving to block sodium diffusion from glass 301 ,

[0096] • a first high index layer 302,

[0097] • a first optically matching layer 303,

[0098] • a first wetting layer 304,

[0099] • a first silver inclusive layer 305,

[0100] • a first blocker layer 306,

[0101] • a first blocker-overcoat layer 307,

[0102] • a first optical control layer 308,

[0103] • a first protective layer 320, and

[0104] • a second protective layer 321 .

[0105] When an additional silver inclusive layer is included in the stack, between the first optical control layer 308 and the first protective layer 320, the following layer configuration is included: • a second optically matching layer 309,

[0106] • a second wetting layer 310,

[0107] • a second silver inclusive layer 311 ,

[0108] • a second blocker layer 312,

[0109] • a second blocker-overcoat layer 313, and

[0110] • a second optical control layer 314.

[0111] When yet another additional silver inclusive layer is included in the stack, between the second optical control layer 314 and the first protective layer 320, the following layer configuration is included:

[0112] • a third optically matching layer 315,

[0113] • a third wetting layer 316,

[0114] • a third silver inclusive layer 317,

[0115] • a third blocker layer 318, and

[0116] • a third blocker-overcoat layer 319.

[0117] The optional sodium diffusion barrier layer 301 is selected from the group comprising SiOxNy or SisN4. The sodium diffusion barrier layer has a thickness from 10 to 50 nm, more preferably from 12 to 20 nm.

[0118] The high-index layer 302 is selected from the group comprising NbOx, TiSiOx, TiSrOx, TiOx. The high-index layer has a thickness from 0 to 15 nm, more preferably from 0 to 8 nm.

[0119] The first 303, second 309 and third 315 optically matching layer is selected from the group comprising ZnAIO, ZnSnOx. The optically matching layer has a thickness from 0 to 30 nm, more preferably from 7 to 20 nm.

[0120] The first 304, second 310 and third 316 wetting layer is selected from the group comprising pure metallics such as Ti, and metallic alloys as NiCr and NbZr. The wetting layer has a thickness from 0.8 to 30 nm. More preferably the first wetting layer has a thickness from 2 to 8 nm, the second wetting layer has a thickness from 5 to 18 nm and the third wetting layer has a thickness from 0.6 to 1.2 nm.

[0121] The first 305, second 311 and third 317 silver functional layer is selected from the group comprising Ag or an Ag alloy. The first and second silver functional layer has a thickness from 9 to 25 nm, more preferably from 12 to 20 nm. The third silver functional layer has a thickness from 5 to 25 nm, more preferably from 5 to 10 nm.

[0122] The first 306, second 312 and third 318 blocker layer is selected from the group comprising NiCrOx, NiCr. The first and second blocker layer has a thickness from 0.9 to 2.5 nm, more preferably from 1 .0 to 1.5 nm. The third blocker layer has a thickness from 0.9 to 25 nm, more preferably from 15 to 18 nm.

[0123] The first 307, second 313 and third 319 blocker overcoat layer is selected from the group comprising ZnAIOx and ZnSnOx. The blocker overcoat layer has a thickness from 0 to 30 nm. More preferably the first and second blocker overcoat layer has a thickness from 12 to 18 nm and the third blocker layer from 15 to 25 nm.

[0124] The first 308 and second 314 optical control layer is selected from the group comprising ZnSnOx, ZnAIOx. The first optical control layer has a thickness from 30 to 70 nm, more preferably from 45 to 60 nm. The second optical control layer has a thickness from 15 to 45 nm, more preferably from 17 to 30 nm.

[0125] The first 320 and second 321 protective layer is selected from the group comprising, Sisl^ , SiOxNy and SiC>2 The protective layer has a thickness from 0 to 50 nm, more preferably from 25 to 40 nm.

[0126] The three darkening means may each be used alone or in any combination. This has the advantage of allowing for dark solar coatings, polymeric films and functional films to be used that are not as dark as would otherwise be needed. This can help to reduce cost. Rather than having to use a coating with a very low VLT, as an example, a 60% VLT coating could be used with a 60% polymeric layer and a 60% VLT functional film to get a total VLT of 20%.

[0127] Examples

[0128] Preferred examples as illustrated in the figures include the following general configuration: The glazing is a large panoramic laminated roof, with a length of 1400 mm and a width of 1100 mm. The first glass layer 201 is comprised of a clear soda-lime glass composition with a thickness of 3.2 mm. The second glass layer 202 is an ultra-clear soda-lime glass with a thickness of 2.1 mm. A black obscuration 6 is printed on surface two 102 of the first glass layer 201 prior to the application of the coating. A black obscuration 6 is also printed on surface four 104 of the second glass layer 202. A clear PVB plastic bonding layer 4 is used with a thickness of 0.76 mm. The lighting means 12 comprises a set of two light bars 24 comprising an array of LEDs with each light bar emitting 1000 lumens and mounted to the edge of glass along the front to rear long edges of the glazing. The LEDs and associated components are mounted to a flexible printed circuit. Each light bar is optically coupled to the edge of glass 92 by means of an optically transparent adhesive 14.

[0129] The light decoupling means is comprised of a special ink containing microscopic particles of a transparent material with an index of refraction that allows the light trapped by TIR within the light conductive layer to decouple and be emitted. The ink is printed on surface four 104 of the light conductive layer 202,40 after the black obscuration 6 is printed but before the additional coating 18 a low-e coating is applied to surface four 104. The standard solar control coating 41 and the dark solar control coating 42 comprise an MSVD coating deposited upon surface two 102 of the first glass layer 201 .

[0130] In a first example, as mentioned in the first preferred embodiment, according to fig. 3A, 3B and 5A the laminated glazing of the invention depicts when the darkening means is a functional film. The layer sequence of the glazing is as follows:

[0131] • a first glass layer 201 of clear soda-lime glass with a thickness of 2.1 mm,

[0132] • a standard solar control coating with a VLT of greater than 75% 41 applied to surface two 102 of the first glass layer 201 ,

[0133] • a first plastic bonding layer 4 of clear PVB with a thickness of 0.76 mm,

[0134] • a functional film 22, 30 of a black switchable PDLC,

[0135] • a second plastic bonding layer 4 of clear PVB with a thickness of 0.76 mm,

[0136] • a second glass layer 202 of ultra-clear soda-lime glass with a thickness of 2.1 mm, and

[0137] • a low-E anti-reflective coating 18 applied to surface four 104 of the second glass layer 202:

[0138] The functional film has a VLT ranging from 10% to 20% with the full VLT of the laminated glazing ranging from 5% to 15%.

[0139] In a second example, as mentioned in the second preferred embodiment, according to fig. 2B, 3B, 4B, the laminated glazing of the invention depicts when the darkening means is a dark polymeric film. The layer sequence of the glazing is as follows:

[0140] • a first glass layer 201 of clear soda-lime glass with a thickness of 2.1 mm,

[0141] • a standard solar control coating with a VLT of greater than 75% 41 applied to surface two 102 of the first glass layer 201 • a dark polymeric film 2 of grey PVB with a thickness of 0,76mm,

[0142] • a plastic bonding layer 4 of clear PVB with a thickness of 0,76 mm,

[0143] • a second glass layer 202 of ultra-clear soda-lime glass with a thickness of 2,1 mm, and

[0144] • a low-E anti-reflective coating 18 applied to surface four 104 of the second glass layer 202:

[0145] The reduction of optical effects, such as shades and waves, at the edges of the glass where the light is injected was reduced in 53% in comparison to a glazing having the same sequence, but without including the clear PVB layer.

[0146] In a third example, as mentioned in the third preferred embodiment, according to fig. 2A, 3B, 4A the laminated glazing of the invention_depicts when the darkening means is the dark solar control 42 coating. The layer sequence of the glazing is as follows:

[0147] • a first glass layer 201 of clear soda-lime glass with a thickness of 2.1 mm,

[0148] • a dark solar control coating 42 applied to surface two 102 of the first glass layer 201 , comprising:

[0149] - a barrier layer layer 301 of SisN4 with a thickness of 13.6 nm,

[0150] - a first high index layer 302 of TiC>2 with a thickness of 4.5 nm,

[0151] - a first optically matching layer 303 of ZnAIO with a thickness of 15 nm,

[0152] - a first wetting layer 304 of NiCr with a thickness of 6 nm,

[0153] - a first silver inclusive layer (305) of Ag with a thickness of 16.7 nm,

[0154] - a first blocker layer 306 of NiCrOx with a thickness of 1.2 nm, and

[0155] - a first blocker-overcoat layer 307 of ZnAIO with a thickness of 15 nm,

[0156] - a first optical control layer 308 of ZnSnOx with a thickness of 55.3 nm,

[0157] - a second optically matching layer 309 of ZnAIO with a thickness of 8 nm,

[0158] - a second wetting layer 310 of NiCr with a thickness of 12.2 nm,

[0159] - a second silver inclusive layer 311 of Ag with a thickness of 10 nm,

[0160] - a second blocker layer 312 of NiCrOx with a thickness of 1.1 nm, and

[0161] - a second blocker-overcoat layer 313 of ZnAIO with a thickness of 15 nm,

[0162] - a second optical control layer 314 of ZnSnOx with a thickness of 20 nm,

[0163] - a third optically matching layer 315 of ZnAIO with a thickness of 13.7 nm,

[0164] - a third wetting layer 316 of NiCr with a thickness of 0.9 nm,

[0165] - a third silver inclusive layer 317 of Ag with a thickness of 7 nm,

[0166] - a third blocker layer 318 of NiCrOx with a thickness of 17.1 nm,

[0167] - a third blocker-overcoat layer 319 of ZnAIO with a thickness of 20 nm,

[0168] - a first protective layer 320 of SiOxNy with a thickness of 32 nm, and - a second protective layer 321 of SiO2with a thickness of 32 nm.

[0169] • a plastic bonding layer 4 of clear PVB with a thickness of 0.76 mm,

[0170] • a second glass layer 202 of ultra-clear soda-lime glass with a thickness of 2.1 mm, and

[0171] • a low-E anti-reflective coating 18 applied to surface four 104 of the second glass layer 202:

[0172] The key performance characteristics for the laminated full stack include visible light transmission, VTL, equal to 10%, reflectivity of the exterior facing surface, R_ext of approximately ~=15%, total transmitted solar energy, TTS measured according to 13837 (2021) of approximately 15%, and transmitted ultra-violet, Tuv of 0.9%. In addition, color is good, neutral at normal and angles of incidence.

[0173] Example four is similar to examples one, two and three and is illustrated in Figures 3B and 5B. A combination of dark solar control coating 42, dark polymeric film 2 and functional film 22 are used as solar control means. Each having a VLT that is higher than required when used alone as the darkening means.

[0174] Example five is similar to the second example. Rather than a functional film 22 is arranged between the dark polymeric film 2 and the plastic bonding layer 4.

[0175] Example six is similar to the first example. Rather than the solar control means 20 is the dark solar control coating 42.

[0176] Example seven is similar to the first example. Rather than the solar control means 20 is the dark solar control coating 42 and the functional film 22 is an PDLC or an PNLC.

[0177] Example eight is similar to example one. Rather than edge injection of light, the lighting means 12 injects light into surface four 104 as shown in Figure 1.

[0178] Example nine is similar to example two. Rather than edge injection of light, the lighting means 12 injects light into surface four 104 as shown in Figure 1.

[0179] Example ten is similar to example three. Rather than edge injection of light, the lighting means 12 injects light into surface four 104 as shown in Figure 1.

[0180] Example eleven is similar to example four. Rather than edge injection of light, the lighting means 12 injects light into surface four 104 as shown in Figure 1.

Claims

CLAIMS1. A luminous glazing, comprising: a first glass layer having an outer major surface, surface one, and an inner major surface, surface two, wherein the outer major surface is opposite to the inner major surface, and the first glass layer has an edge surface; a second glass layer having an inner major surface, surface three, and an outer major surface, surface four, wherein the outer major surface is opposite to the inner major surface and the second glass layer has an edge surface ; at least one plastic bonding layer arranged between the inner major surface of the first glass layer and the inner major surface of the second glass layer; a darkening means arranged between the inner major surface of the first glass layer and the at least one plastic bonding layer; a solar control means; a light conductive layer; and at least one lighting means configured to couple its light into the light conductive layer. wherein the second glass layer is the light conductive layer; and wherein the solar control means is the darkening means or is arranged between the first glass layer and the darkening means.

2. The luminous glazing of claim 1 wherein, the solar control means is a solar control coating layer deposited onto the inner major surface of the first glass layer.

3. The luminous glazing of any one of the preceding claims, wherein the first glass layer has a total visible light transmission of at least 80%, preferably of at least 86%, more preferably of at least 89% measured according to ISO 9050 (2003).

4. The luminous glazing of any one of the preceding claims, wherein the second glass layer has a total visible light transmission of at least 86%, preferably of at least 89%.

5. The luminous glazing of any one of the preceding claims, wherein the luminous glazing has total visible light transmission from 0 to 25%, preferably from 0 to 14%, more preferably from 4 to 10%.

6. The luminous glazing of any one of the preceding claims, wherein the light emitted from the at least one lighting means is coupled into the edge surface of the light conductive layer or is coupled into the outer major surface of the light conductive layer.

7. The luminous glazing of any one of the preceding claims, wherein the lighting means comprises a light source, preferably at least one light bar.

8. The luminous glazing of claim 7, wherein the light source of the lighting means is selected from the group comprising red, green, blue, white, LEDs (RGBW), and / or red, green, blue, LEDS (RGB), and / or single wavelength light sources and / or monochromatic light sources and / or a combination thereof.

9. The luminous glazing of claim 7, wherein the light source is disposed on a flexible printed circuit, a printed circuit board (PCB) and / or a semi-flexible PCB.

10. The luminous glazing of any one of the preceding claims, wherein the first glass layer and the second glass layer are selected from the group comprising aluminosilicate, soda lime, or borosilicate glass.

11. The luminous glazing of any one of the preceding claims, wherein the at least one plastic bonding layer is selected from the group comprising polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), thermoplastic polyurethane (TPU), polyolefin elastomers (PoE), polyethylene terephthalate (PET), optical adhesive resins (OCR) or a combination thereof.

12. The luminous glazing of any one of the preceding, wherein the plastic bonding layer is in direct contact with the light conductive layer and has a total visible light transmission of at least 80%, preferably from 80 to 90% according to ISO 9050 (2003) performing the measurement to the plastic bonding layer laminated between two glass layers each of them having a VLT of at least 88%.

13. The luminous glazing of any one of the preceding claims, wherein the at least one plastic bonding layer is a clear PVB having a total visible light transmission of at least 86% measured according to ISO 9050 (2003) performing the measurement to the plastic bonding layer laminated between two glass layers each of them having a VLT of at least 88%.

14. The luminous glazing of any one of the preceding claims, further comprising an additional coating selected from anti-reflective coating, LowE, anti-fingerprint and combinations thereof and is deposited on the outer major surface of the second glass layer.

15. The luminous glazing of any one of the preceding claims, wherein the darkening means is selected from the group comprising a functional film, a dark polymeric film, the solar control means and a combination of thereof.

16. The luminous glazing of any one of the preceding claims, wherein the darkening means has a total visible light transmission from 0 to 60 %, preferably from 0 to 18%, more preferably from 0 to 10%.

17. The luminous glazing of any one of the preceding claims, wherein the darkening means comprises a colored functional film selected from the group comprising suspended particle device (SPD), polymer dispensed liquid crystal (PDLC), Polymer Network Liquid Crystal PNLC, liquid crystal (LC) and electrochromic (EC) and having a total visible light transmission ranging from 0 to 60% measured according to ISO 9050 (2003) performing the measurement directly to the switchable films.

18. The luminous glazing of claim 17, wherein the colored functional film is selected from the group comprising black-PDLC and a black- PNLC.

19. The luminous glazing of claim 13, wherein the darkening means comprises a dark polymeric film selected from PET, EVA, PVB and PU; wherein said dark polymeric film has a total visible light transmission ranging from 0 to 18% measured according to ISO 9050 (2003) performing the measurement to the dark polymeric layer laminated between two glass layers each of them having a VLT of at least 88%; and wherein the darkening means is separated from the light conductive layer by the clear plastic bonding layer arranged between the second glass layer and the dark polymeric film.

20. The luminous glazing of claim 19, wherein the plastic bonding layer is in direct contact with the dark polymeric film.

21. The luminous glazing of claim 15, wherein the darkening means is the solar-control means deposited as a coating onto the inner major surface of the first glass layer; having a total visible light transmission from 0 to 18% measured according to ISO 9050 (2003), performing the measurement to the solar control coating 42 deposited onto the glass.

22. The luminous glazing of claim 21 , wherein the solar-control coating is multilayer coating comprising the following configuration:• a first high index layer,• a first optically matching layer,• a first wetting layer,• a first silver inclusive layer,• a first blocker layer,• a first blocker-overcoat layer,• a first optical control layer, and• at least one protective layer.

23. The luminous glazing of any one of the preceding claims, wherein the glazing is an automotive roof.

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