Electrically controllable device having an electroactive layer containing liquid crystals and a polymeric barrier between the electroactive layer and an electrode

Abstract

A device having a scattering which can be varied by liquid crystals includes a first electrode, an electroactive layer and a second electrode. It includes, between the first electrode and the electroactive layer, a first transparent polymeric barrier layer with a thickness of T.sub.1 and optionally, between the second electrode and the electroactive layer, a second transparent polymeric barrier layer with a thickness of T.sub.2, T.sub.1 being nonzero and at least 1 μm, and T.sub.1+T.sub.2 being at most 40 μm. The first polymeric barrier layer carries the first electrode or the first electrode is on a first dielectric substrate. The second optional polymeric barrier layer carries the second electrode or the second electrode is on a second dielectric substrate.

Claims

1. An electrically controllable device having a scattering which is variable by liquid crystals, comprising: a first transparent substrate; a second transparent substrate, and a stack of layers arranged between the first and the second transparent substrates, the stack of layer comprising in this order a first electrode comprising a first electrically conductive layer, an electroactive layer containing liquid crystals and a plurality of spacers, alternating reversibly between a scattering state and a transparent state, by application of an alternating electric field, the electroactive layer having a micronic thickness T.sub.0, the plurality of spacers arranged within the electroactive layer and spaced apart from one another to define the micronic thickness of the electroactive layer, a second electrode comprising a second electrically conductive layer, the electroactive layer being visible by transparency on a side of the first electrode or on a side of the second electrode, or both, wherein the stack comprises, between the first electrode and the electroactive layer, a first transparent polymeric barrier layer with a thickness of T.sub.1 and optionally, between the second electrode and the electroactive layer, a second transparent polymeric barrier layer with a thickness of T.sub.2, wherein the thickness T.sub.1 of the first transparent polymeric barrier layer is at least 7 μm, and T.sub.1+T.sub.2 being at most 40 μm, wherein the first transparent polymeric barrier layer carries the first electrode on a first main exterior face oriented on a side opposite the electroactive layer or the first electrode is on a first main internal face of a first dielectric substrate oriented toward the electroactive layer, and wherein the second optional polymeric barrier layer carries the second electrode on a second main exterior face oriented on the side opposite the electroactive layer or the second electrode is on a second main internal face of a second dielectric substrate oriented toward the electroactive layer.

2. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first polymeric barrier layer is a first transparent film based on polymeric material chosen from a polyester, a polycarbonate, a polyolefin, a polyurethane, a polyamide, a polyimide or a fluoropolymer.

3. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first transparent polymeric barrier layer is a transparent film with a thickness T.sub.1 of at most 25 μm and the second polymeric layer is absent.

4. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first transparent polymeric barrier layer is a transparent film with a thickness T.sub.1 of at most 20 μm and the second polymeric layer is a transparent film with a thickness T.sub.2 of at most 20 μm.

5. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first dielectric substrate is transparent and carries the first electrode and the first polymeric barrier layer chosen from the following polymers: polyacrylate, polyester, polyurethane, polyamide, polyethylene, polyalcohol, polyvinylpyrrolidone, polycarbonate, polystyrene, cellulose polymer or synthetic latex.

6. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first dielectric substrate is transparent and carries the first electrode which is transparent and is chosen from a first glass sheet or a first transparent polymeric sheet with on the side of the first external face opposite the first internal face an optional hard coat.

7. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 6, wherein the first electrode is mineral and the device comprises, between the first electrode and the first transparent polymeric barrier film, a transparent and polymeric adhesion layer which is electrically conductive or which is dielectric and with a thickness T.sub.3 of at most 10 μm.

8. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first dielectric substrate is a first glass sheet which is, on the side of the first external face opposite the first internal face, laminated via a thermoplastic lamination interlayer with another glass sheet.

9. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first polymeric barrier layer is a first film carrying the first electrode and optionally the second polymeric barrier layer is a second film carrying the second electrode.

10. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 9, further comprising a first additional transparent sheet, polymeric or made of glass, bonded to the first electrode by a first transparent dielectric adhesive layer or by a thermoplastic lamination interlayer.

11. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, wherein the first polymeric barrier layer is tinted.

12. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, further comprising a laminated glazing comprising: a first glass sheet formed by said first transparent substrate, a thermoplastic lamination interlayer, a second additional glass sheet or a plastic sheet formed by said second transparent substrate, wherein main internal faces of the first and second additional glass sheets face one another, the stack being between the main internal faces.

13. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, further comprising a glazing including said first and second transparent substrates and wherein the stack forms a strip over a portion of a main face of said glazing.

14. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 1, further comprising a laminated glazing including said first and second transparent substrates, and wherein the stack forms a peripheral strip over an upper portion of the laminated glazing, an external edge face of the stack being masked from the outside by a first opaque peripheral layer on an exterior glazing formed by one of the first and second transparent substrates, or an internal edge face of the stack being masked from the inside by a second opaque peripheral layer on the interior glazing formed by the other one of the first and second transparent substrates.

15. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 13, wherein the glazing is laminated and is bent and is chosen from a glazing of an automobile or rail or nautical vehicle.

16. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 13, wherein the glazing is a glazed door, a shop window or display case, a partition, a glazed portion of street or household furniture and/or forms part of a double or triple glazing.

17. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 2, wherein the polymeric material is a polyethylene terephthalate or a polyethylene naphthalate.

18. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 9, wherein the first polymeric barrier layer is a first transparent film and the second polymeric barrier layer is a second transparent film.

19. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 10, wherein the first transparent dielectric adhesive layer is an optically clear adhesive.

20. The electrically controllable device having a scattering which can be varied by liquid crystals as claimed in claim 13, wherein the glazing is a laminated or bent glazing, or both.

Description

(1) Other details and characteristics of the invention will become apparent from the detailed description which will follow, given with regard to the following appended drawings:

(2) FIG. 1, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a first embodiment of the invention,

(3) FIG. 2, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a second embodiment of the invention,

(4) FIG. 3, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a third embodiment of the invention,

(5) FIG. 4, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a fourth embodiment of the invention,

(6) FIG. 5, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a fifth embodiment of the invention,

(7) FIG. 6, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a sixth embodiment of the invention,

(8) FIG. 7, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a seventh embodiment of the invention,

(9) FIG. 8, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in an eighth embodiment of the invention,

(10) FIG. 9, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a ninth embodiment of the invention,

(11) FIG. 10, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a tenth embodiment of the invention,

(12) FIG. 11, representing a diagrammatic sectional view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in an eleventh embodiment of the invention,

(13) FIG. 12, representing a diagrammatic front view of a device having a scattering which can be varied by liquid crystals with polymeric barrier film in a twelfth embodiment of the invention,

(14) FIG. 12′, representing a diagrammatic sectional view of the device having a scattering which can be varied by liquid crystals with polymeric barrier film of FIG. 12.

(15) The elements in the figures are not represented to scale.

EXAMPLE 1

(16) Exemplary embodiment No. 1 represented in FIG. 1 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 100.

(17) Electrodes 2,2′ made of indium tin oxide (ITO) with a sheet resistance of 40 ohm/square, more broadly between 5 and 300 ohm/square, are deposited, on the main internal faces 11,11′, on two plastic substrates, in particular polyester substrates, and better still such as of PET, 1 and 1′ with a thickness of 50 to 300 μm, for example of 175 μm. And, for neutrality in colors, each electrode can also comprise at least two thin dielectric underlayers under the ITO layer.

(18) In order to supply electricity, conductive bands (not shown), in particular metallic conductive bands, for example made of copper, are fixed, for example by adhesive bonding, along and on peripheral edges of the internal faces 11,11′ and are in contact with the electrodes 2,2′ (one band per electrode, the bands preferably being on opposite edges), These bands can protrude over at least one side of the edge face of the substrate 1,1′ involved. These bands are subsequently connected to an electrical supply (not shown).

(19) The PET substrates 1,1′ can be of any shape, for example rectangular, round or square, and of any size, for example with a length of at least 1 m and even with a width of at least 10 cm (strip, and the like). They can have a thickness preferably of greater than 100 μm and of at most 300 μm for better mechanical strength of the assembly and/or for ease of processing or of handling but, if greater flexibility is desired, it is possible to go down, for example, to 50 μm.

(20) A layer 3 of liquid crystals is located between the electrodes 2,2′. More specifically, the layer 3 of liquid crystals is, for example, of PDLC type and contains liquid crystals in the form of microdroplets dispersed in a matrix 3a made of polymer. The layer 3 also contains spherical spacers 3′ made of transparent polymer. The thickness of the layer 3 is, for example, 15 μm and can vary from 5 to 45 μm typically.

(21) Use may be made of liquid crystals such as the compound 4-((4-ethyl-2,6-difluorophenyl)ethynyl)-4′-propylbiphenyl and 2-fluoro-4,4′-bis(trans-4-propylcyclohexyl)biphenyl, for example sold by Merck under the reference MDA-00-3506.

(22) In an alternative form which is less preferred, use is made of a layer of liquid crystals with spacers and without addition of polymer.

(23) The edge faces 20,20′ of the electrodes 2,2′ and the edge 30 of the electroactive layer are preferably set back with respect to the edge 10,10′ of the PET substrates 1,1′.

(24) In order to prevent short-circuits, a plastic barrier film, preferably made of PET, 4, which is transparent, with a thickness of 12 μm or even 25 μm, is present on the first ITO electrode 2 (which is on the first PET substrate 1) and under the layer of liquid crystals 3. The barrier film 4 can cover the first electrode 2 (at least the active part) and its edge 40 can be set back from the edge 10,10′ of the PET substrates 1,1′, be in their alignment or even extend beyond, for example over just one side of the edge 10,10′. The absorption of this PET barrier film 4 is less than 0.1% and it has a haze of less than 1.5%. The PET barrier film 4 can be a monolayer or a multilayer. For example, it is a trilayer (by coextrusion), such as the product Lumirror U60 from Toray, the core of which, made of PET, between two coextruded external layers (also made of PET).

(25) The PET barrier film 4 can have, on one or each main face, a conventional functional layer (adhesion promoter, and the like). One or each main face of the PET barrier film 4 may have undergone a chemical surface treatment, such as a grafting of molecular monolayers or an addition of surfactants.

(26) Preference is given to a PET barrier film 4 of at least 10 μm, which is more readily available.

(27) In the “OFF” state, that is to say before the application of an electric voltage, this glazing having liquid crystals 100 is scattering, that is to say that it transmits optically but is not transparent. As soon as a sinusoidal voltage is applied between the two electrodes, the layer 3 changes to the transparent state, that is to say the state in which the view is not impeded.

(28) The addition of the barrier film 4 causes the voltage to increase very slightly to 120 V approximately.

(29) By the application of a direct voltage of 100 V, the resistance of the device 100 is virtually infinite (10 gigaohms) versus ˜1 kiloohm for a similar device without barrier film. This demonstrates the absence of short-circuits by virtue of the invention.

(30) The layer of liquid crystals 3 is preferably set back with respect to the edge of first PET substrates 1, 1′ and also set back from the edge of the barrier film 4. Better still, the layer of liquid crystals 3 can be surrounded by an adhesive seal (not shown) made of crosslinked polymer which, on the main face 42 and the ITO layer 2′ (or directly the internal face 12′ of the second PET substrate 1′), serves at the same time to connect, in a closed and permanent manner, the second PET substrate 1′ and the barrier film 4.

(31) The PET barrier film 4 can extend beyond the edge of the PET substrates 1,1′ over one side, two sides, three sides or the four sides.

(32) The PET barrier film 4 can facilitate the electrical connection of the first electrode.

(33) The exterior face 12 of the first PET 1′ comprises a hard coat, for example formed by application of an acrylate-based mixture, such as the product SR344 and the product SR399 from Sartomer Company.

(34) The exterior face 12′ of the first PET 1′ comprises a temporary protective film which, after removal, leaves visible and ready-for-use a layer of adhesive 5a covering the face 12′ or forming a peripheral frame for fixing the stack to a portion or all of the surface of a transparent support (plastic sheet, single or laminated glazing on an internal or external surface of a glazing of a double or triple glazing, and the like).

(35) In an alternative to the self-supporting PET (or more broadly polyester) barrier film, a PP film, for example a multilayer PP film, is chosen.

(36) In an alternative to the self-supporting barrier film, a deposit by the liquid route, which has to have a thickness of at least 1 μm, is chosen as polymeric barrier layer.

(37) The advantage of a self-sporting film is its uniformity in thickness, the ease of tailor-making and its availability on a large scale at low cost.

(38) In an alternative, the PET barrier film is tinted and/or the first and/or second carrier substrate (plastic or other) is tinted.

(39) In an alternative to the choice of ITO, alone or in a multilayer, a silver-containing stack is chosen for one or both electrodes. It is even possible to choose, for one of the electrodes, a layer with a lower T.sub.L or even a reflecting layer.

(40) One or the external faces of the first and second carrier substrates 1,1′ can comprise one or more functional layers (antireflective, and the like) already known.

(41) One of the first and second carrier substrates 1,1′, and even the associated electrode, can be greater in size than the remainder of the stack. For example, the electrically conductive layer, such as ITO (or other), can act as solar control layer or else as heating layer. The ITO region acting as electrode can then be isolated by laser etching, for example, in order to form an ITO strip.

(42) One and/or other of the first and second carrier substrates 1,1′ can be replaced by a glass sheet, for example of 0.7 mm to 4 mm, with or without a layer on its external face, or else by a plastic sheet—with or without a layer on its external face—for example thicker (such as from 1 to 10 mm), a polycarbonate or else a PMMA.

(43) The manufacturing process of example No. 1 is described more precisely below.

(44) The following mixture is prepared in order to form the layer of liquid crystals: 0.45 g of photoinitiator A (MXM035-A, sold by Nematel), 3.8 g of monomer B (MXM035-B, sold by Nematel), 5.75 g of liquid crystals (MDA-00-3506, for example from Merck), 0.03 g of polymeric spacers with a diameter of 15 μm (SP-215 from Sekisui).

(45) Other examples of compositions, based on acrylate and on mercaptan, are described in the application U.S. Pat. No. 4,891,152.

(46) This mixture is deposited dropwise on the second PET substrate 1′ with the second ITO electrode 2′ (and preferably its already adhesively-bonded conductive strip) without extending as far as the edge face of the film, preferably. Preferably, a peripheral sealing seal is formed in an edge region with the ITO or even in a marginal region without ITO close to the edge face of the PET 1′. The seal can be interrupted by one or more vents. In order to form the seal, a “preseal” material containing precursors of the crosslinked polymer forming the seal, is likewise applied directly along the edge of the PET substrate after (indeed even before) the deposition of the composition of the layer having PDLC liquid crystals. The preseal forms a cord which is or will be in contact with the composition of the layer of PDLC liquid crystals. More specifically, the seal adhesive material contains, for example, a mixture of isobornyl acrylate, of 2-hydroxyethyl methacrylate phosphate and of acrylate oligomers, for example forming at least 10% by weight of the preseal, indeed even at least 30% by weight of the preseal, and which also contains a filler (mineral powder) and a photoinitiator for its polymerization and crosslinking with ultraviolet radiation.

(47) The barrier film 4 is affixed to the optional sealing seal and to the mixture using a roll, thus forming a continuous layer without extending as far as the edge face of the film, preferably.

(48) The UV treatment for the polymerization is carried out for 100 s (UV source), thus forming the polymeric layer with liquid crystals and also the optional seal.

(49) The first PET substrate 1 with the first ITO electrode 2 (and preferably its already adhesively-bonded conductive strip) is superimposed on the barrier film 4, preferably after the UV treatment.

(50) Alternatively to the application of the barrier film by a roll, a calendaring (or, in an alternative form, a pressing) is carried out.

(51) The preseal, having vents, and the layer of PDLC liquid crystals are compressed down to the thickness of the spacers. The vents are thus used to discharge the air as calendaring is carried out and/or to discharge the possible excess of layer of liquid crystals.

(52) The application of an additional material, forming a bridge between the ends of the seal, preferably based on acrylate polymer precursor and devoid of epoxy precursor and for example made of said seal material, thus forming material continuity, is subsequently provided for.

(53) The operation of polymerization of the matrix and of crosslinking of the adhesive seal and of the additional material is subsequently carried out by irradiation with UV light.

(54) It should be noted that the ITO layers 2,2′ are preferably deposited by magnetron cathode sputtering. The ITO layers 2,2′ are deposited, for example, using a ceramic target in an argon/oxygen atmosphere in an alternative form.

EXAMPLE 2

(55) Exemplary embodiment No. 2 represented in FIG. 2 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 200.

(56) The device 200 differs from the preceding one in that it comprises, between the barrier film 4 (PET, and the like) and the first electrode 2 (ITO, and the like), a layer for promoting contact, “adhesion layer”, 6 made of conducting polymer, such as PEDOT/PSS, or, in an alternative form, a dielectric layer made of hydrogel, with a main internal face 61 on the side of the electroactive layer 3 and a main external face 62 on the side opposite the electroactive layer.

(57) During manufacture, the barrier film 4 with the first electrode 2 can be preassembled with the adhesion layer 6 and the first substrate with the ITO 2 and then the assembly can be applied against the electroactive layer based on liquid crystals 3.

(58) In an alternative, the adhesion layer is deposited on the barrier film 4 already applied against the layer based on liquid crystals 3.

(59) In an alternative, the adhesion layer is deposited on the first electrode 2 and against the barrier film 4 already applied against the layer based on liquid crystals 3.

EXAMPLE 3

(60) Exemplary embodiment No. 3 represented in FIG. 3 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 300.

(61) The device 300 differs from the first device 100 in that: the barrier film 4 carries the first electrode layer 2, with the result that the first substrate is eliminated, optionally, the second substrate 1′ is chosen to be made of glass (which can be an ultrathin glass UTG, a thin glass or glass of standard thickness), for better strength, an additional glass sheet 8, for example made of clear or extra-clear glass and of at least 1 mm, which can be equal to or greater than the remainder of the stack in size, is adhesively bonded via an optically clear adhesive 7′ (of any thickness) based on polyester or acrylic or on silicone for example, starting from the Dow Adcote compositions mixing the product 76R44 (modified polyester) with the product (coreactant) 9L10, or else the PSAs from Oribain (BPS family, and the like).

(62) Neither is it necessary to retain a hard coat or a sheet of liner type.

(63) During manufacture, the carrier barrier film 4 of the first electrode 2 can be preassembled by adhesive bonding with the glass sheet and then applied against the electroactive layer 3 based on liquid crystals.

(64) In an alternative, the layer of adhesive 7′ is either deposited on the first electrode 2 and the glass 8 is assembled or on the glass 8 and the adhesive-treated glass is assembled.

EXAMPLE 4

(65) Exemplary embodiment No. 4 represented in FIG. 4 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 400.

(66) The device 400 differs from the first device 100 in that: the barrier film 4 carries the first electrode 2, with the result that the first substrate is eliminated, and also the hard coat, the first electrode 2 is optionally coated with a temporary protective adhesive film 5, in particular with a layer of adhesive, such as already described (OCA, pressure-sensitive, and the like) on the side of the first electrode 2, in order to fix the stack to a portion or the whole of the surface of a transparent support (glazing, plastic sheet, and the like), the second carrier substrate 1′ comprises a hard coat as already described, rather than a temporary adhesive film.

(67) Alternatively, the temporary adhesive film is maintained on the side of the second carrier substrate 1′ while optionally retaining that on the first electrode side, for example if the stack is between two transparent supports (glazing, plastic sheet, and the like) over a portion or the whole of their surfaces.

EXAMPLE 5

(68) Exemplary embodiment No. 5 represented in FIG. 5 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 500.

(69) The device 500 differs from the first device 100 in that: the barrier film 4 carries the first electrode layer 2, with the result that the first substrate is eliminated, a first plastic film, such as PET 1″, in particular with a thickness of 50 to 300 μm, is adhesively bonded by its internal face 11″ via an optically clear adhesive 7′ (such as already described) to the first electrode 2, it being possible for its external face 12″ to have a hard coat 5′, the first electrode 2 is optionally coated with a temporary protective adhesive film 5, in particular with a layer of adhesive, such as already described (OCA, pressure-sensitive, and the like) on the side of the first electrode 2, in order to fix the stack to a portion or the whole of the surface of a transparent support (plastic sheet, glazing, and the like), the second substrate 1′ is a glass sheet, the external face 12′ of which is laminated via a thermoplastic lamination interlayer 7, for example PVB or EVA or PU, with another glass sheet, indeed even plastic sheet (rigid, for example), 8.
The edge 70 of this interlayer can be set back from the edge 80 of the other sheet 8.

(70) The complete device 500 can act as partition.

(71) Preferably, the lamination occurs after the UV polymerization and before the application of the external plastic film 1″.

(72) The laminated glazing and also the associated electrode 2′ can have greater sizes than the remainder of the stack. For example, the electrode layer (ITO or other) can act as solar control layer or else as heating layer. The region acting as electrode can then be isolated by laser etching, for example, in order to form a strip.

EXAMPLE 6

(73) Exemplary embodiment No. 6 represented in FIG. 6 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 600.

(74) The device 600 differs from the first device 100 in that: the first substrate 1 carrying the first electrode 2 is a glass sheet, with a free external face (or with an antireflective layer, and the like), and, in an alternative form, the external face 12 is laminated via a thermoplastic lamination interlayer, for example PVB or EVA or PU, with another glass sheet, indeed even a plastic (rigid, and the like), a second polymeric barrier film, preferably of the same material (and sizes) as the first (PET), 4′, with a thickness T.sub.2, for example of 12 μm, is between the electroactive layer 3 and the second electrode and even in this instance the second barrier film 4′ carries the second electrode layer 2′, with the result that the second substrate is eliminated.

(75) The main external face 42′ of the second barrier film is in contact with the second electrode 2′ and its main internal face 41′ is in contact with the electroactive layer 3. The edge 40′ of the second barrier film can be aligned with that 40 of the first film 4 or the edge of the first substrate 1.

(76) It is possible to choose to reduce the thickness T.sub.1 (and to lower T.sub.2) by the addition of a second barrier film 7′. For example, T.sub.1 and T.sub.2 (which are not necessarily equal) are chosen between 2 and 10 μm. Like for the first film, the second can be tinted depending on the demands.

(77) The first carrier substrate, in this instance glazing 1, and also the associated first electrode 2 can have greater sizes than the remainder of the stack. For example, the ITO (or other) layer can act as solar control layer or else as heating layer. The ITO region acting as electrode can then be isolated by laser etching, for example, in order to form an ITO strip.

EXAMPLE 7

(78) Exemplary embodiment No. 7 represented in FIG. 7 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 700.

(79) The device 700 differs from the first device 100 in that: the first barrier film 4′ carries the first electrode layer 2′, with the result that the second substrate is eliminated, a temporary protective adhesive film 5 optionally being added, a second polymeric barrier film, preferably of the same material as the first (PET), 4′, with a thickness T.sub.2, for example of 12 μm, is between the electroactive layer 3 and the second electrode 2′ and even in this instance the second barrier film 4′ carries the second electrode layer 2′, with the result that the second substrate is eliminated.

(80) It is possible to choose to reduce the thickness T.sub.1 (and to thicken T.sub.2) by the addition of a second barrier film. For example, T.sub.1 and T.sub.2 (which are not necessarily equal) are chosen between 2 and 10 μm. Like for the first film, the second can be tinted depending on the demands.

(81) The device 700 can be flexible, can fit the curvatures of a support of the same size or of greater size (on the preferably external face of the shower wall, on the preferably internal face (face “F4”) of a bent vehicle glazing, in particular bent automobile glazing: roof, side window, windshield).

EXAMPLE 8

(82) Exemplary embodiment No. 8 represented in FIG. 8 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 800.

(83) The device 800 differs from the preceding device 700 in that the first electrode 2 is adhesively bonded, via an optically clear adhesive 7′, to a glass sheet 8 (flat, bent, tempered, and the like).

(84) The glass sheet 8 can be greater in size than the remainder of the stack.

EXAMPLE 9

(85) Exemplary embodiment No. 9 represented in FIG. 9 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 900.

(86) The device 900 comprises the second device 200 which is in a laminated glazing, that is to say in a lamination interlayer 7, for example PVB or EVA, which is submillimetric or of at most 2 mm, between a first and a second glazing 8,8′, for example of rectangular (or more broadly quadrilateral, polygonal) general shape, with identical or similar dimensions, for example with a thickness of at most 5 mm or 3 mm, with main internal faces 81,81′ on the interlayer side and main external faces 82,82′.

(87) During manufacture, it is possible to use three interlayer sheets: two full sheets 71,72 against the internal faces 81,81′ of the glazings 8,8′ and a central sheet 73 with an opening for housing the stack 200. After lamination, the interface between sheets (symbolized in dotted lines) is not necessarily discernible. It is preferable for the opening to be closed rather than completely emerging on one side. Thus, the entire edge of the stack is surrounded with lamination interlayer 7. Naturally, for the electrical supply, connections can exit from the device 200 and even protrude over one or more sides of the edges of the glazings. Alternatively, it is possible to use two interlayer sheets 71,72, the central hollowed-out sheet not being necessary if the stack is sufficiently thin, for example with a thickness of at most 0.2 mm.

(88) The first glazing 8 or 8′ can be tinted (gray, green, bronze, and the like) and the other glazing 8′ or 8 clear or extra-clear. A first interlayer sheet can be tinted (gray, green, bronze, and the like) and the other(s) clear or extra-clear. One of the first glazings 8 or 8′ can be replaced by a plastic sheet, such as a polycarbonate or a PMMA (in particular with a lamination interlayer made of PU).

(89) The edge 70 of the lamination interlayer can be set back (by at most 5 mm, for example) from the edge 80,80′ of the glazings 8,8′.

(90) The device 200 covers virtually the whole of the main faces 81 to 82′ and even in this instance is centered. There is the same width of PVB 7a,7b on either side of the device 200.

(91) The glazings 8,8′ are flat or bent, it being possible for the device 200 to fit the curvature(s) of the glazings.

(92) The device 900 can be a partition or else a vehicle roof. For example, for an automobile roof: the glazing 8 is the bent exterior glazing, which is a tinted glazing of 3 mm, the glazing 8′ is the bent interior glazing, which is a clear glazing of 3 mm or thinner, the lamination interlayer 8 is made of PVB, which can be acoustic, in particular bilayer or trilayer (sheet 71 or 72).

EXAMPLE 10

(93) Exemplary embodiment No. 10 represented in FIG. 10 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 101.

(94) The device 101 differs from the preceding device 900 in that the barrier film 4 carries the first electrode (ITO, and the like) 2; the main external face of the latter is thus in contact with the lamination interlayer (the first substrate being eliminated).

(95) During manufacture, it is possible to use three interlayer sheets: two full sheets 71,72 against the internal faces 81,81′ of the glazings 8,8′ and a central sheet 73 with an opening for housing the stack. Alternatively, it is possible to use two interlayer sheets 71,72, the central hollowed-out sheet not being necessary if the stack is sufficiently thin, for example with a thickness of at most 0.2 mm.

(96) After lamination, the interface between sheets (symbolized in dotted lines) is not necessarily discernible.

EXAMPLE 11

(97) Exemplary embodiment No. 11 represented in FIG. 11 shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 101.

(98) The device 110 differs from the preceding device 101 in that it comprises a second barrier film 4′ carries the second electrode (ITO, and the like) 2′; the main external face of the latter is thus in contact with the lamination interlayer (the second substrate being eliminated).

(99) During manufacture, it is possible to use three interlayer sheets: two full sheets 71,72 against the internal faces 81,81′ of the glazings 8,8′ and a central sheet 73 with an opening for housing the stack. Alternatively, it is possible to use two interlayer sheets 71,72, the central hollowed-out sheet not being necessary if the stack is sufficiently thin, for example with a thickness of at most 0.2 mm.

(100) After lamination, the interface between sheets (symbolized in dotted lines) is not necessarily discernible.

EXAMPLE 12

(101) Exemplary embodiment No. 12 represented in FIGS. 12 and 12′ shows an electrically controllable device having a scattering which can be varied by liquid crystals according to the invention 120.

(102) The device 120 differs from the ninth device 900 in that the stack 200 covers a surface portion, in particular a peripheral strip, for example along an upper longitudinal edge H of an automobile vehicle windshield (bent laminated glazing with the device 200), over virtually the whole length of the windshield.

(103) This strip 200 is in a marginal region in which the criteria of T.sub.L and of absence of haze are looser than in the central region ZB.

(104) As shown in FIG. 12′ (sectional view), the width 7a of central interlayer 73 between the device 200 and the lower longitudinal edge B is greater than the width 7b of central interlayer 73 between the device 200 and the upper longitudinal edge H.

(105) In an alternative form or simultaneously, it can be present along a lower longitudinal edge B of the windshield, over the entire length or a portion of length.

(106) As shown in FIG. 12 (front view, interior side of the vehicle), the windshield comprises a first opaque frame, for example made of enamel (black or other), 91′ to 94′ over the lateral and longitudinal edges of the free face (F4) 82′ of the internal glazing 8′ and a second opaque frame, for example made of enamel (black or other), 91 to 94 over the lateral and longitudinal edges of the free face (F1) 82 of the external glazing 8.

(107) The edge face of the device 200, which is on the side of the lower longitudinal edge, and even those on the sides of the lateral edges, can be between the layers 92, 92′, 93, 93′, 94, 94′ of the enamel frames. For example, the connections and other strips for conveying current can also be masked by these layers 92, 92′, 93, 93′, 94, 94′.