Laminated glazing with variable transmission

Abstract

Laminated glazing (1) with variable light transmission by liquid crystals comprising at least a first main glass substrate (10), a second main glass substrate (11), at least one liquid crystal cell (2) including dichroic dyes, the cell (2) being arranged between the first and second glass substrates (10, 11), and at least one UV filter (3) blocking UV up to 380 nm, characterized in that the laminated glazing further comprises a first filter element (5) which filters visible light in the wavelength range A from 380 to 450 nm, and a second filter element (6) which filters visible light in the wavelength range B from 451 to 700 nm, such that the laminated glazing, in its clear state at maximum light transmission, has an average transmission T(A) of less than 30% over the wavelength range A, an average transmission T(B) of 0.1 to 40% in the B wavelength range,and transmission colorimetric coordinates a* from -6 to 5, preferably from -4 to 0, and b* from -5 to 5, preferably from -3 to 3.,

Description

Title of the invention: Laminated glazing with variable transmission

[0001] The invention relates to the field of electrically controllable glazing with variable optical properties, in particular laminated glazing with variable transmission by liquid crystals and comprising dichroic dyes as well as a UV filter.

[0002] An electrically controllable glazing with variable optical properties has the ability to opacify the transparency of the glazing when an electrical voltage is applied to switchable functional elements integrated into the glazing. These functional elements are, for example, liquid crystals.

[0003] The invention will be more particularly described with regard to the use of a laminated glazing with variable transmission by liquid crystals in an application of exterior glazing (for vehicles such as motor vehicles, trains, aircraft), without however being limited thereto. It may in particular be applied to interior glazed surfaces (for buildings).

[0004] A laminated glazing with variable transmission by liquid crystals, comprises at least two main glass substrates, two interlayer lamination films made of plastic, very often polyvinyl butyral (PVB), and a liquid crystal cell placed between the two interlayer lamination films. The liquid crystal cell comprises liquid crystals in combination most often with dichroic dyes (such a host-guest cell is called "GHLC" for "Guest-Host Liquid Crystal" in English), encapsulated between two encapsulation substrates (generally polymeric encapsulation films) which are kept at a constant distance thanks to spacers such as glass or plastic beads. Each of the encapsulation substrates is provided with an electrode.When a voltage is applied to the electrodes, the liquid crystals change orientation and alter the light transmission through the cell, the glazing changing from a clear state to a dark state, or vice versa. The terms "clear state" and "dark state" refer to the state of the glazing at its maximum, or minimum, light transmission.

[0005] However, in certain applications, in particular for exterior glazing, the optical performance deteriorates over time because the dichroic dyes of the liquid crystal cell are sensitive to light irradiation and / or heat. The ultraviolet (UV) spectral component and the infrared (IR) spectral component in particular lead to a degradation of the dichroic dyes, manifesting itself for example by their change of color and causing an unsightly discoloration of the glazing as well as a reduced contrast between the two switching states.

[0006] In order to protect the dichroic dyes from UV rays (between 320 nm and 380 nm) and near IR rays (between 0.7 and 2.5 pm), the glazing may comprise UV blockers or absorbers or UV reflectors that filter out ultraviolet radiation and IR reflectors or IR absorbers. UV blockers or absorbers, for example, consist of intermediate layers in the glazing or liquid crystals loaded with UV-absorbing molecules. IR reflectors are layers integrated into the laminated glazing, which are capable of reflecting IR and are called low-emissivity layers or solar control layers. However, it has been found that the durability of liquid crystal cells with dichroic dyes is not yet as expected.

[0007] Furthermore, significant progress has been made in the light and / or temperature stability of GHLC cells by working on the chemical formulation of dichroic dyes. Thus, certain molecules are less sensitive to degradation by light and / or temperature, which can make it possible to dispense with the addition of UV filters. Nevertheless, these molecules have optical performances that are lower than those expected for glazing.

[0008] Consequently, liquid crystal cells which have high optical performance use dichroic dyes which unfortunately have limited stability to light and / or temperature, and the UV and IR filters which can be associated do not yet have sufficient performance with regard to the durability of liquid crystal cells with dichroic dyes.

[0009] The invention therefore aims to propose a laminated glazing with switchable functional elements of the liquid crystal and dichroic dye type (usually called a "guest-host" system), which does not have the aforementioned drawbacks, in particular a glazing whose switchable functional elements do not deteriorate rapidly over time.

[0010] According to the invention, the laminated glazing with variable light transmission by liquid crystals comprises at least a first main glass substrate, a second main glass substrate, at least one liquid crystal cell including dichroic dyes, the cell being arranged between the first and second glass substrates, and at least one UV filter blocking UV up to 380 nm, and is characterized in that the laminated glazing further comprises a first filtering element which filters visible light in the wavelength range A from 380 to 450 nm, and a second filtering element which filters visible light in the wavelength range B from 451 to 700 nm, such that the laminated glazing, in its clear state at maximum light transmission, has an average transmission T(A) of less than 30% over the wavelength range A, an average transmission T(B) of 0.1 to 40% over the wavelength range B waves,and transmission colorimetric coordinates a* from 6 to 5, preferably from -4 to 0, and b* from -5 to 5, preferably from -3 to 3. ,

[0011] The light transmission (TL) through a glazing is measured according to the ISO 9050:2023 standard with illuminant D65. An average transmission corresponds to the arithmetic mean of the transmissions over the wavelength range considered, considering for example a step of 1 nm.

[0012] In the remainder of the description, the term "which filters" means that part of the light radiation is blocked or attenuated, by absorption or by reflection, i.e. only part of the radiation, over the wavelength range considered, passes through the filtering element. In other words, an element which filters at least X% over a given wavelength range means that it has an average transmission of at most 100-X% over this range considered.

[0013] Hereinafter, the expression “liquid crystal cell” means a liquid crystal cell incorporating dichroic dyes.

[0014] By deliberately adding at least one element with a filter function in visible light, not only in visible light up to 450 nm but also up to 700 nm, while providing a transmission as mentioned above, the inventors have demonstrated that the durability of the liquid crystal glazing including dichroic dyes was significantly improved. In addition, the glazing retains its aesthetic appearance, that is to say that it does not exhibit any notable color deviation, in particular towards yellow. Finally, the choice of the combination of filter elements according to the invention makes it possible to maximize the light transmission of the glazing in the clear state, thus retaining its functional aspect: the provision of two states, clear and dark, with sufficiently differentiated light transmission.Thus, the solution of the invention makes it possible to retain a UV filter coupled to the liquid crystal cell (the UV filter being a simple and inexpensive means of protecting the glazing and therefore the liquid crystal cell from wavelengths up to 380 nm) and to further increase the durability of the liquid crystal glazing while preserving both the functional and aesthetic aspects of the glazing.

[0015] According to one characteristic, the second filter element has an absorption spectrum comprising at least one absorption peak having a half-maximum width L of at least 10 nm and at most 100 nm over the wavelength range B, in particular a half-maximum width L of less than or equal to 50 nm over the wavelength range B. In addition, according to one characteristic, the absorption peak has a maximum intensity Imax of between 5% and 100%. In particular, the ratio Imax / L is preferably between 10 1 nm 1 and 5.10 4 nm '.

[0016] According to one characteristic, the first filtering element filters at least 40% of the visible light in the wavelength range A, in particular at least 50%, or even at least 60% in the wavelength range A between 380 nm and 450 nm, in particular at least 90%, preferably at least 95%, or even at least 98%, over the wavelength range A of 380 to 450 nm.

[0017] It was not obvious how to achieve such a high-performance protection result for the liquid crystal cell incorporating dichroic dyes with the glazing of the invention. The gain in durability is indeed much greater than a simple relationship of proportionality of filtration percentage. For example, if 5% of the incident visible light is filtered in the wavelength range A, one would expect to reduce the degradation due to visible light by approximately 5%. However, filtration of less than 5% of the visible light in the wavelength range A, coupled with filtration in the wavelength range B, makes it possible to reduce the degradation of the liquid crystal cell by a factor of 4 or 5.The inventors have also demonstrated that the combination of the two filtering elements with the UV filter preserves the aesthetic appearance of the glazing (without color deviation), which is greatly appreciated, particularly for vehicle or building glazing.

[0018] In an exemplary embodiment, the first filter element further filters at least 99%, preferably 100%, of the wavelengths below 380 nm and thus also constitutes the UV filter. Alternatively, the first filter element is physically distinct from the UV filter.

[0019] According to one characteristic, the first filter element is a mass-colored glass substrate, or a thin layer deposited on a glass substrate providing coloring of said glass substrate, or a colored plastic film.

[0020] According to one characteristic, the second filter element is a mass-colored glass substrate, or a thin layer deposited on a glass substrate, or a colored plastic film.

[0021] Each of the first and second filter elements may be a colored element that includes one or more coloring agents in combination.

[0022] According to one characteristic, when the first main glass substrate is turned towards the external environment in the position of use of the glazing, the first filtering element is arranged between said first main glass substrate and the liquid crystal cell, while the second filtering element is arranged between the first filtering element and the liquid crystal cell, or between the liquid crystal cell and the second main glass substrate.

[0023] In an exemplary embodiment, the first filter element and the second filter element form a single film of plastic material. In particular, this single film absorbs, by the plastic material of which it is made or by the presence of additives, in the wavelength range A, in particular beyond 410 nm, so as to provide the first filter element and further comprises one or more agents dyes absorbing in the wavelength range B so as to provide the second filter element.

[0024] In another embodiment, the UV filter, the first filter element and the second filter element form a single film made of plastic. In particular, this single film comprises anti-UV agents and absorbs, by the plastic material of which it is made or by the presence of additives (including possibly the anti-UV agents), in the wavelength range A, in particular beyond 410 nm, so as to provide the first filter element and further comprises one or more coloring agents absorbing in the wavelength range B so as to provide the second filter element.

[0025] In a particular embodiment, the second filter element is a colored plastic film (comprising a polymer matrix and at least one coloring agent dispersed in the matrix).

[0026] In another embodiment, the first filter element is a mass-colored glass substrate and the second filter element is a colored polymer layer deposited on a glass substrate. In particular, the polymer layer constituting the second filter element has a thickness of between 0.1 mm and 2 mm, preferably at most 1 mm.

[0027] According to one characteristic, the glazing has, in its clear state at maximum light transmission, a light transmission (TL) greater than 5%. In particular, a laminated glazing according to the invention in the automobile, such as a glass roof or a windshield (lower and / or upper zones), the TL of the glazing is less than or equal to 5% in the dark state, preferably less than 2%, more preferably less than 1% or even less than 0.5%, and the TL is greater than or equal to 5% in the clear state, preferably at least between 15% and 20%, and the contrast of the TL between the dark and light states is between 2 and 100.

[0028] In an exemplary embodiment, the UV filter is a thin layer applied to the internal or external face of the first main glass substrate (glass substrate intended to be turned outwards in the position of use of the glazing), or is a plastic film arranged between the first main glass substrate and the liquid crystal cell.

[0029] According to one characteristic, the UV filter and / or the first filter element and / or the second filter element is a film made of polymeric material which is based on at least one polymer chosen from the following polymers: polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), polyethylene terephthalate (PET), polyethylene, polycarbonate, polymethylmethacrylate, polyacrylate, polyvinyl chloride, polyacetate resin, acrylate, fluorinated ethylene propylene, polyvinyl fluoride, ethylene tetrafluoroethylene, cyclic olefin copolymer (COC), material transparent adhesive (OCA for "Optical Clear Adhesive" in English). The OCA is in particular of the acrylic, polyvinyl acetate (PVA), polyurethane (PU), silicone, or epoxy type. The transparent adhesive material (OCA) can be deposited in the solid state of pressure-sensitive type (PSA film), or in the liquid state (resin) and cured during the lamination process forming after curing an interlayer film. The thickness of the polymeric film is preferably between 0.02 mm and 2 mm, preferably from 0.3 mm to 1 mm.

[0030] According to an exemplary embodiment, the liquid crystal cell comprises encapsulation substrates made of encapsulation films made of polymeric material.

[0031] According to another exemplary embodiment, the liquid crystal cell comprises encapsulation substrates made of encapsulation glass substrates, the cell being laminated so that each of the two encapsulation glass substrates is made integral with one of the two main glass substrates via at least one plastic interlayer, at least one interlayer being the UV filter and at least one interlayer being the first filter element and / or the second filter element.

[0032] According to another characteristic, the laminated glazing comprises at least one infrared protective coating, in particular the infrared protective coating being arranged on the internal or external face of the first main glass substrate and preferably on the external or internal face of the second main glass substrate. The infrared protective coating is for example a thin layer applied to the internal or external face of the first main glass substrate and / or an interlayer film arranged between the first main glass substrate and the liquid crystal cell. This configuration makes it possible to reflect the IR so that the heat and / or the IR radiation do not degrade the dichroic coloring agents of the liquid crystal cell.

[0033] According to another characteristic, the liquid crystal cell integrating dichroic dyes is a host-guest cell called “GHLC” (for “Guest-Host Liquid Crystal” in English) or a polymer-based cell such as a PDLC cell (for “Polymer-Dispersed Liquid Crystal” in English), or a PNLC cell (for “Polymer Network Liquid Crystal” in English) or a PSLC cell (for “Polymer stabilized liquid crystal”).

[0034] The laminated glazing may include other functionalities, which are added via coatings in direct contact with the main glass substrates and / or (the encapsulation substrates of) the liquid crystal cell and / or with interlayer films, or which are provided directly by one or more interlayer films. These various functionalities are, for example, acoustic, anti-reflective, non-stick, anti-scratch, photocatalytic, anti-fingerprint, anti-fog, light extraction properties, etc.

[0035] The laminated glazing of the invention can constitute building glazing.

[0036] The laminated glazing of the invention may constitute vehicle glazing, in particular a vehicle chosen from an automobile, a train, a truck, an aircraft, a military vehicle, a tractor and a bus.

[0037] If it is vehicle glazing, the laminated glazing is in particular chosen from roof glazing, a rear window, a side window, a windshield, and a gradient band of the upper part of the windshield.

[0038] Laminated glazing can be flat or curved.

[0039] Laminated glazing can be used in double glazing or in triple glazing.

[0040] The present invention is now described using examples which are purely illustrative and in no way limitative of the scope of the invention, and from figure [Fig.l] which represents a schematic sectional view of laminated glazing according to an exemplary embodiment of the invention.

[0041] For the sake of clarity, the various elements represented in the figures are not reproduced to scale.

[0042] The laminated glazing 1 of the invention illustrated in [Fig.l] is a laminated glazing with variable transmission by liquid crystals comprising a liquid crystal cell 2 integrating dichroic dyes. The glazing of the invention aims to effectively increase the durability and stability over time of the dichroic dyes of the liquid crystal cell 2. To this end, in addition to a UV filter blocking UV up to 380 nm, the glazing 1 comprises a first filtering element which filters visible light in the wavelength range A from 380 to 450 nm and a second filtering element which filters visible light in the wavelength range B from 451 to 700 nm.

[0043] The laminated glazing 1 is intended for a building application or a vehicle application. The laminated glazing 1 has its light transmission modified when an electrical voltage is applied to the electrodes of the liquid crystal cell 2. The glazing 1 can be normally clear (with maximum light transmission) in the absence of voltage, and it becomes dark (with minimum light transmission), by applying a voltage. Conversely, the glazing can be conceived as normally dark, without voltage; it then becomes clear by applying a voltage. The normally clear or normally dark state depends on the use of the glazing.

[0044] Depending on the uses made of the laminated glazing 1 described below with regard to [Fig. 1] or in envisaged variants not illustrated, it will be used in a single-piece manner as is as single glazing, or will be combined with one or more other laminated or spaced glass substrates.

[0045] The laminated glazing 1 illustrated in [Fig.l] comprises a first main glass substrate 10, a second main glass substrate 11 arranged at a distance and opposite the first substrate 10, the liquid crystal cell 2 arranged at the heart of the glazing, a UV filter 3 blocking UV up to 380 nm and interlayer elements, here 40, 41 and 42, for securing the liquid crystal cell 2 to the glass substrates 10 and 11 and / or to the first and second filter elements, and said first and second filter elements 5 and 6. Depending on the nature of the liquid crystal cell 2 and the constituent support (the matrix) of the filter elements, the intermediate securing elements may for example be a PVB film or an OCA layer. The intermediate securing elements have in particular a thickness of between 0.1 mm and 2 mm, in particular 0.38 mm or 0.76 mm.

[0046] The main glass substrates 10 and 11 have a thickness suitable for the use of laminated glazing. The thickness may be between 0.3 mm and 15 mm, preferably between 1 and 5 mm; it is for example 1.6 mm, 1.8 mm or 2.1 mm.

[0047] The liquid crystal cell 2 is for example a guest-host liquid crystal cell comprising a liquid volume of liquid crystals mixed with dichroic dyes. The liquid crystal cell 2 is of the known type.

[0048] The first glass substrate 10 being intended to be turned towards the external environment, the UV filter 3 is associated with it.

[0049] The UV filter 3 is made of a polymeric material such as PVB, having the property of cutting ultraviolet rays up to 380 nm. The ultraviolet cutting property is preferably provided by molecules dispersed in the polymeric matrix of the film, which are capable of blocking ultraviolet rays and which do not absorb visible radiation.

[0050] The UV filter 3 has a transmission for each wavelength in the wavelength range from 280 nm to 380 nm of less than 1%, preferably less than 0.1%, more preferably less than 0.01%, preferably equal to 0%.

[0051] In addition, the glazing 1 comprises the first filtering element 5 which filters visible light in the wavelength range A from 380 to 450 nm, and the second filtering element 6 which filters visible light in the wavelength range B from 451 to 700 nm, the first and second filtering elements 5 and 6 being such that the laminated glazing 1, in its clear state at maximum light transmission, has an average transmission T(A) of less than 30% over the wavelength range A, an average transmission T(B) of 0.1 to 40% over the wavelength range B, and colorimetric coordinates in transmission a* of -6 to 5, preferably of -4 to 0, and b* of -5 to 5, preferably of -3 to 3.

[0052] The first filter element 5 is a mass-colored glass substrate, or a thin layer deposited on a glass substrate, or a colored plastic film. The second filter element 6 is a mass-colored glass substrate, or a thin layer deposited on a glass substrate, or a colored plastic film. The coloring agents of the first and second filter elements 5 and 6 are selected to provide the aforementioned filtering properties for the glazing.

[0053] In order to protect the liquid crystal cell 2 against the heat of infrared radiation, the glazing 1 preferably comprises an infrared protective coating 70 (solar control) which is arranged on the internal face (called face F2) of the first main glass substrate 10 (when this first glass substrate is intended to be turned towards the outside, such as the outside of the passenger compartment of the vehicle). This IR protective coating protects the liquid crystal cell 2 from the heat that the glazing can undergo due to solar radiation.

[0054] The glazing 1 may comprise a low-emissive layer 71 on the external face of the second main glass substrate 11 (face intended to be turned towards the passenger compartment of the vehicle, called face F4) to minimize heat loss in the passenger compartment in winter and the sensation of a cold wall.

[0055] In the example illustrated in [Fig.l], stacked from the first glass substrate 10 and between said first glass substrate 10 and the liquid crystal cell 2 are the infrared protective coating 70, the UV filter 3, the first filter element 5 which is a colored glass substrate, an interlayer 40 such as a PVB film, a glass substrate 60 whose TL is preferably at least 91%, the second filter element 6 with a polymer matrix deposited on the glass substrate 60, and an OCA 4L. The interlayer 40 has made it possible to secure the first filter element 5 made of glass to the glass substrate 60. The OCA 41a has made it possible to secure the polymer matrix of the second filter element 6 to the liquid crystal cell 2 whose encapsulation substrates are polymeric. On the other side of the liquid crystal cell 2, said cell is secured to the second glass substrate 11 by an OCA 42.

[0056] In this illustrated example, - the UV 3 filter is a commercial PVB film that filters ultraviolet rays, for example the film sold under the name Saflex®PVB from the Eastman company, 0.76 mm thick, which filters 99% up to 380 nm; - the first filter element 5 is a glass substrate which is colored (the glass of the glass substrate comprising a coloring agent) and has a thickness of 0.38 mm. The colored glass substrate constituting the first filter element 5 is commercially available, for example the product marketed under the name GG435 from the company SCHOTT. This first filter element 5 filters visible light up to 435 nm, so that it has zero transmission for each wavelength up to 435 nm; - the second filter element 6 is a polymeric layer comprising a coloring agent. The coloring agent is for example the product marketed under the name FDG-005 from the company Yamada Chemicals. This dye FDG-005 has an absorbance peak at 580 nm, and a width at half maximum of 30 nm at a concentration of 0.26% relative to the total dry weight and for a film thickness of 8 pm; - the glass substrate 60 comprising the second filter element 6 is a clear glass such as the product marketed under the name PLANICLEAR® from the company SAINT-GOBAIN; its thickness is 2.1 mm.

[0057] More particularly, in the above-mentioned example for the second filter element 6, a solution is prepared comprising a solvent such as methyl ethyl ketone (MEK) at 70% by weight, polymethyl methacrylate acrylic (PMMA) at 29.3% by weight and FDG-005 at 0.7% by weight. After mixing, the solution is deposited on the glass substrate 60 by means of a film puller to obtain a layer of 8 μm. After coupling the second filter element 6 to the first filter element 5 by assembling the glass substrate 60 of the second filter element 6 to the first filter element 5 via the interlayer 40, the second filter element 6 is located on the side of the liquid crystal cell 2.

[0058] The combination of the UV filter 3 as well as the first filter element 5 and second filter element 6 acting respectively in the visible wavelength ranges A and B, makes it possible to effectively increase the durability and stability over time of the dichroic dyes of the liquid crystal cell 2, while preserving its aesthetic properties. The light transmission of the glazing of the aforementioned example remains entirely acceptable in the clear state with an average transmission T(A) of 3% over the wavelength range A, an average transmission T(B) of 17% over the wavelength range B, and colorimetric coordinates in transmission a* of -2 and b* of 1 according to the CIE illuminant D65 2° (CIE 1931).

[0059] Furthermore, the color variation AE of the glazing of the aforementioned example is less than 5, after an accelerated aging test which corresponds to 1400 hours of operation of the liquid crystal cell 2, whereas comparatively, a glazing with the same liquid crystal cell 2 protected by the single and same UV filter 3 has a color variation AE of 26 after the same accelerated aging test.

[0060] Thus, the inventors have surprisingly demonstrated that by adding to the UV filter which filters up to 380 nm, the first filtering element and the second filtering element according to the invention which filter respectively in the visible beyond 380 nm up to 450 nm and between 451 nm and 700 nm, it is possible to increase the durability and stability of the liquid crystal cell 2 and of the dichroic dyes, and therefore of the glazing 1, while preserving the aesthetic and functional aspects of the glazing.

Claims

Claims

1. Laminated glazing (1) with variable light transmission by liquid crystals comprising at least a first main glass substrate (10), a second main glass substrate (11), at least one liquid crystal cell (2) including dichroic dyes, the cell (2) being arranged between the first and second glass substrates (10, 11), and at least one UV filter (3) blocking UV up to 380 nm, characterized in that the laminated glazing further comprises a first filter element (5) which filters visible light in the wavelength range A from 380 to 450 nm, and a second filter element (6) which filters visible light in the wavelength range B from 451 to 700 nm, such that the laminated glazing, in its clear state at maximum light transmission, has an average transmission T(A) of less than 30% over the wavelength range A, a average transmission T(B) from 0.1 to 40% over the wavelength range B,and transmission colorimetric coordinates a* from -6 to 5, preferably from 4 to 0, and b* from -5 to 5, preferably from -3 to 3.,

2. Laminated glazing according to claim 1, characterized in that the second filter element (6) has an absorption spectrum comprising at least one absorption peak having a half-height width L of at least 10 nm and at most 100 nm over the wavelength range B, in particular a half-height width L of less than or equal to 50 nm over the wavelength range B.

3. Laminated glazing according to the preceding claim, characterized in that the absorption peak has a maximum intensity Imax of between 5% and 100%, the ratio Imax / L preferably being between 10 1 nm1 and 5.10 4 nm

4. Laminated glazing according to any one of the preceding claims, characterized in that the first filtering element (5) filters at least 40% of the visible light in the wavelength range A, in particular at least 50%, or even at least 60%, in particular at least 90%, preferably at least 95%, or even at least 98%, in the wavelength range A.

5. Laminated glazing according to one of the preceding claims, characterized in that the first filtering element (5) filters at least 99%, preferably 100%, of wavelengths below 380 nm and also constitutes the UV filter.

6. Laminated glazing according to one of claims 1 to 4, characterized in that the first filtering element (5) is physically distinct from the UV filter (3).

7. Laminated glazing according to any one of the preceding claims, characterized in that the first filtering element (5) is a mass-colored glass substrate, or a thin layer deposited on a glass substrate, or a colored plastic film.

8. Laminated glazing according to any one of the preceding claims, characterized in that the second filtering element (6) is a mass-colored glass substrate, or a thin layer deposited on a glass substrate, or a colored plastic film.

9. Laminated glazing according to any one of the preceding claims, characterized in that when the first main glass substrate (10) is turned towards the external environment in the position of use of the glazing, the first filtering element (5) is arranged between said first main glass substrate (10) and the liquid crystal cell (2), while the second filtering element (6) is arranged between the first filtering element (5) and the liquid crystal cell (2), or between the liquid crystal cell (2) and the second main glass substrate (11).

10. Laminated glazing according to any one of the preceding claims, characterized in that the first filter element (5) and the second filter element (6) form a single film of plastic material.

11. Laminated glazing according to any one of claims 1 to 5, characterized in that the UV filter (3), the first filter element (5) and the second filter element (6) form a single film of plastic material.

12. Laminated glazing according to any one of claims 1 to 9, characterized in that the first filter element (5) is a mass-colored glass substrate and the second filter element (6) is a colored polymeric layer deposited on a glass substrate.

13. Laminated glazing according to any one of the preceding claims, characterized in that it comprises at least one coating infrared protection (70, 71), in particular the infrared protection coating being arranged on the inner or outer face of the first main glass substrate (10) and preferably on the outer or inner face of the second main glass substrate (11).

14. Laminated glazing according to any one of the preceding claims, characterized in that it is flat or curved, able to be used as single glazing, or used in double glazing or in triple glazing.

15. Laminated glazing according to any one of the preceding claims, characterized in that it is a vehicle glazing chosen from an automobile, a train, a truck, an aircraft, a military vehicle, a tractor and a bus.

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