EP2404214A1

EP2404214A1 - Electrically controllable device with uniform coloration/discoloration over the entire surface thereof

Info

Publication number: EP2404214A1
Application number: EP10711862A
Authority: EP
Inventors: Fabienne Piroux; Emmanuel Valentin; Samuel Dubrenat; Gilles Bokobza
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2009-03-02
Filing date: 2010-03-02
Publication date: 2012-01-11
Also published as: FR2942665A1; WO2010100147A1; KR20110126125A; JP2012519308A; CN102341750A; FR2942665B1; US20110317243A1

Abstract

The invention relates to a device comprising a stack of the following layers, namely: a first substrate with a glazing function (V₁), a first electronically conductive layer (TCC₁) with an associated current supply, an electroactive layer (EA), a second electronically conductive layer (TCC₂) with an associated current supply, and a second substrate with a glazing function (V₂). According to the invention, each of the layers, TCC₁ and TCC₂, is selected to have a resistance per unit area R_ϵthat allows same to have an equipotential surface in terms of coloration and discoloration, each of said layers having a variable resistance R_ϵ that diminishes gradually from the periphery towards the centre of the electronically controllable device and R_ϵ being selected at the centre of the glazing in the zone(s) farthest from the current supplies, such that the ohmic drop across the central surface of the substrates of the glazing in the zone(s) farthest from the current supplies is at most equal to five percent of the value of the voltage applied at the terminals of the device.

Description

ELECTROCOMMANDABLE DEVICE HOMOGENEOUS COLORING / DECOLORIZING ON THE WHOLE SURFACE

The present invention relates to an electrically controllable device with variable optical / energy properties, comprising the following stack of layers:

a first glass-function substrate (V ₁ );

a first electronically conductive layer (TCCi) with an associated current supply; an electro-active system (EA) comprising or consisting of:

at least one electroactive organic compound (eai ⁺ ) capable of being reduced and / or of accepting electrons and cations acting as compensation charges;

at least one electroactive organic compound (ea ₂ ) capable of oxidizing and / or ejecting electrons and cations acting as compensation charges; at least one of said organic compounds electro ^¬ assets (ea ⁺ & ea ₂₎ being electrochromic in order to obtain a color contrast; and

ionic charges capable of allowing, under the action of an electric current, oxidation and reduction reactions of said electroactive organic compounds (eai ⁺ & ea ₂ ), which are necessary to obtain the color contrast;

a second electronically conductive layer (TCC ₂ ) with an associated current supply; and

a second substrate with a glass function (V ₂ ).

The electronically conductive layers are denoted "TCC", abbreviation of the English expression "Transparent Conductive Coating", an example of which is a transparent conductive oxide TCO ("Transparent Conductive Oxide".

The electroactive medium (EA) is a medium in solution or gelled. It can also be contained in a self-supported polymer matrix as described in the international application PCT / FR2008 / 051160 filed on

25/06/2008 or in the European patent application EP 1 786

O QQOJQ. In the case where the two electro-active materials are electrochromic materials, these may be identical or different. In the case where one of the electro-active materials is electrochromic and the other is not, the latter will act as a counterelectrode not participating in the coloring and discoloration of the system.

If it is supposed that the compound (eai ⁺ ) is electrochromic (being, for example, 1,1'-diethyl-4,4'-bipyridinium diperchlorate) and that the compound (ea ₂ ) is electrochromic (being, for example, 5, 10-dihydro-5,10-dimethylphenazine) or non-electrochromic being for example a ferrocene), the redox reactions which are established under the action of the electric current are as follows:

Colorful ea ₂ ≡ ea ₂ ⁺ + e ^"

Colorful if electrochromic Colorless if not electrochromic

In such known devices and according to a first state of the art, as illustrated by the

Figures 1 to 3 described in more detail below, each current supply consists of a thin conductive strip applied along a border of the associated electrically conductive layer, the two strips being located along two opposite edges of the electrically controllable device. In this case, and for small glazing, such as mirrors for example, the transition from faded to faded state can be uniform.

On the other hand, for larger glazings, such as building glazings, the transition from the faded state to the colored state will be done with a curtain effect of having a coloring starting at one or both brought current, then propagating to the rest of the glazing. This is schematically illustrated in Figure 7 of the accompanying drawing.

Moreover, for these large glazings, during the coloring step, but also when the colored state is maximum, the absorption of the glazing will be greater at one or both of the current leads than far from these leads. current.

According to a second state of the art, represented by the French patent application filed on 05/12/2008 under the number 08/58289 in the name of the applicant company and entitled "Electrically controllable device having an improved routing of electrical charges in electro-active medium ", the conductive strips used as current leads are applied all around the conductive layers, facing or substantially facing each other so as to avoid color segregation when the electrochromic device is maintained a long time in the colored state. Figures 4 and 5 below illustrate a glazing according to this second state of the art. As in the previous case, the transition from the faded state to the colored state may be homogeneous for small glazing.

On the other hand, for large glazings, the transition from the faded state to the colored state will be accompanied by a halo effect consisting in a start of the coloration at the level of the current leads. This is illustrated in Figure 9 of the accompanying drawing.

Again, for these large windows, during the coloring step, but also when the colored state is maximum, the absorption of the glazing will be greater at the periphery of the glazing, where are placed the current leads, that in the center of this glazing.

The Applicant Company has therefore sought an effective means to eliminate curtain or halo effects during the electrochromic glazing coloring process and to ensure a uniform absorption value over the entire surface of an electrochromic glazing in colored and discolored states, and when staining and fading steps, regardless of the size of this glazing.

These objectives have been achieved according to the present invention through the use of conductive layers specifically manufactured to limit the ohmic drop at the electrochromic glass electrodes. The results of the present invention can be visualized by comparing Figures 7 and 8 - which illustrate the suppression of the curtain effect - and Figures 9 and 10 - which illustrate the suppression of the halo effect.

The subject of the present invention is therefore an electrically controllable device with variable optical / energy properties, comprising the stack of layers as defined at the very beginning of this description. characterized by the fact that each of the TCCi and TCC ₂ layers is chosen to present a resistance per unit area R _n allowing it to present an equipotential surface in coloration and discoloration, each of the layers TCC1 and TCC2 having a variable resistance R _n gradually decreasing from the periphery to the inside of the electrically controllable device by choosing R _D at the center of the glazing, in the region or regions farthest from the current leads, so that the ohmic drop on the central surface of the substrates of the glazing, in the or the areas furthest away from the current leads, ie not more than five per cent of the value of the voltage applied across the device.

This makes it possible to obtain a homogeneous distribution of the current, the parts of the CBTs having lower value resistivities acting as electron wells. The result is that halo phenomena are avoided.

Indeed, the surface tension V _P at a point P of one of the conductive layers is defined by the equation:

Vp = V _ap pi _iqu e - Ri

in which :

- V _ap pi _ied is the voltage applied to the conductive layer - i is the current

- R is the resistance of the layer defined by the relation:

R = px L / A = px L / (Wxt) = R _D x L / W where

- p is the resistivity of the sample

- L is its length

- A is his section with A = Wxt - W is its width

- t is its thickness

- R _n is the resistance per unit area with R _n = p / t the ratio Ri being the ohmic drop.

Preferably, the two layers TCC1 and TCC2 facing each other are identical.

The TCC1 and TCC2 layers may have a variable resistance R _D gradually decreasing gradually along a gradient.

The grid or microgrid may be of a metal such as aluminum.

The TCCi or TCC ₂ layers may have a variable resistance R _n decreasing gradually in zones. A conducting layer TCCi or TCC ₂ of resistance

Variable R _D advantageously has a resistance that ranges from 20Ω / D or more at the periphery to 5Ω / D or less at the center of the layer.

A TCCl or TCC2 layer may be in the form of a continuous layer or in the form of a grid or a microgrid or in the form of grids or a microgrid coated with a continuous layer.

A TCCi or TCC ₂ layer with variable resistance R _n may have been obtained: by a plasma treatment, a flame or ablation of material from said layer to progressively degrade the conductivity or degrade it by zones;

by deposits, in particular under vacuum, successive conductive material on the glass substrate, the first deposit being made on the entire surface of the substrate, then the subsequent deposit being made on a central region thereof with masking of the region periphery, and so on if other zones must be formed, the deposits other than the first being able to be made in particular on circular regions so that the different zones of the layer are concentric zones, the center of which corresponds to that of the substrate;

by a network of identical or different conductive and / or insulative patterns, which have been formed on at least a portion of the conductive layer deposited on the substrate.

French patent application FR2875669 describes such networks of conductive and / or insulating patterns.

Thus, as indicated in this application, it is possible to create a network of insulating or weakly conductive patterns in the conductive layer (TCC1, TCC2), it is possible to form a network with conductive patterns by filling holes formed in the conductive layer

(TCC1, TCC2) by a more conductive material than the latter, by producing the conductive layer (TCC1, TCC2) with local extra thicknesses forming the pattern network, sufficient thicknesses to obtain the desired characteristics, or by producing portions of a second, more conductive layer (TCC1, TCC2), this second layer being deposited for example by spraying on the layer previously covered with a mask. The conductive patterns include silver points.

The electronically conductive layers TCCi and

TCC ₂ are in particular metal-type layers, such as layers of silver, gold, platinum and copper; or transparent conductive oxide (TCO) type layers, such as tin doped indium oxide layers

(In ₂ O ₃ : Sn or ITO), of indium oxide doped with antimony

(In ₂ O ₃ : S _b ), fluorine-doped tin oxide (SnO ₂ IF) and zinc oxide doped with aluminum (ZnO: Al); or TCO / metal / TCO multilayers, the TCO and the metal being in particular chosen from those enumerated above; or NiC _r / metal / NiC _r multilayers, the metal being in particular chosen from those enumerated above.

The layers TCC1 & TCC2 may each be connected to a current supply constituted by a conductive strip applied to the associated TCC1 or TCC2 layer, the conductive strip possibly being a metal, an alloy or an electrically conductive composite which is deposited directly on the substrate coated with its conductive layer or on a spacer separating the two spacer substrates using for example a vacuum deposition technique or screen printing with a metal paste, or which is welded to the substrate covered with its conductive layer or on a separating spacer the two substrates or else which is adhered by means of an electrically conductive adhesive, the conductive strip applied to a substrate which may be continuous or have discontinuous regions and connected to each other and which may be applied to all or part of each substrate.

The current leads comprise in particular continuous conductive strips applied to the layers TCC1 and TCC2 and disposed all around or substantially all around said conductive layers (TCC1 and TCC2).

The substrates with glass function can be chosen from glass and transparent polymers, such as poly (methyl methacrylate) (PMMA), polycarbonate (PC), poly (ethylene terephthalate) (PET), poly (ethylene naphthoate ) (PEN) and cyclosporin copolymers (COC). Furthermore, between a glass-function substrate, in particular a plastic substrate, and a TCCl or TCC2 layer may be arranged a layer or a stack of layers, this layer or these layers being chosen independently from among the inorganic, organic or organic-inorganic hybrids, and having been deposited on the substrate before the deposition of the associated TCC1 or TCC2 layer in order notably to improve the adhesion of TCC1 or TCC2 to the substrate or to provide an additional function such as impermeability to gases and to moisture. By way of example of such an intermediate layer, there may be mentioned a layer of Si ₃ N ₄ or SiO ₂ which in particular acts as a barrier to moisture and oxygen. According to a first variant, the electroactive system (EA) can comprise a self-supporting polymer matrix in which the electroactive organic compound (s) (eai ⁺ & ea ₂ ) and the ionic charges are inserted, said polymer matrix containing in its entirety in a liquid (L) solubilizing said ionic charges but not solubilizing said self-supporting polymer matrix, the latter being chosen to ensure a percolation path of the ionic charges to allow said oxidation and reduction reactions of said electroactive organic compounds (eai ⁺ & ea ₂ ), the ionic charges being carried by at least one of said electroactive organic compounds (eai ⁺ & ea ₂ ) and / or reduced and oxidized species which are respectively associated with them (eai and ea ₂ ⁺ ) and / or by at least one ionic salt and / or at least one acid solubilized in said liquid (L) and / or by said self-supporting polymer matrix; the liquid (L) being constituted by a solvent or a mixture of solvents and / or by at least one ionic liquid or molten salt at ambient temperature, the said ionic liquid or molten salt or the said ionic liquids or molten salts then constituting a liquid (L ) carrying ionic charges, which represent all or part of the ionic charges of said electro-active system.

According to a second variant, the electro-active system may comprise a solution or a gel containing the electroactive organic compounds (eai ⁺ & ea ₂ ).

The electroactive organic compound (s) (eai ⁺ ) may or may be chosen from bipyridiniums or viologenes such as 1,1'-diethyl-4,4'-bipyridinium diperchlorate, pyraziniums, pyrimidiniums, quinoxaliniums, pyryliums, pyridiniums, tetrazoliums, verdazyls, quinones, quinodimethanes, tricyanovinylbenzenes, tetracyanoethylene, polysulfides and disulphides, as well as all the electro-active polymeric derivatives of the electro-active compounds which have just been mentioned ; and the electroactive organic compound (s) (ea ₂ ) is or are chosen from metallocenes, such as cobaltocenes, ferrocenes, N, N, N ', N' -tetramethylphenylenediamine (TMPD), phenothiazines such as phenothiazine, dihydrophenazines such as 5,10-dihydro-5,10-dimethylphenazine, reduced methylphenothiazone (MPT), methylene violet bernthsen (MVB), verdazyls, and all electroactive polymeric derivatives of the compounds electro-actives that have just been mentioned.

The ionic salt or salts may be chosen from lithium perchlorate, the salts trifluoromethanesulfonates or triflates, trifluoromethanesulfonylimide salts and ammonium salts; the acid or acids are chosen from sulfuric acid (H ₂ SO ₄ ), triflic acid (CF ₃ SO ₃ H), phosphoric acid (H ₃ PO ₄ ) and polyphosphoric acid (H _{n + 2} P _n 0 _{3n +} 1); the one or more solvents may be chosen from dimethylsulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, propylene carbonate, ethylene carbonate and N-methyl-2-pyrrolidone (1-methyl-2); pyrrolidinone), gamma-butyrolactone, ethylene glycols, alcohols, ketones, nitriles and water, the ionic liquid (s) may be chosen from imidazolium salts, such as 1-ethyl-3- methylimidazolium tetrafluoroborate (emim-BF ₄ ), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (emim-CF ₃ SO ₃ ), 1-ethyl-3-methylimidazolium bis (trifluoromethylsulphonyl) imide (emim-N (CF ₃ SO ₂ ) ₂ or emim-TSFI) and 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (bmim-N (CF ₃ SO ₂ ) ₂ or bmim-TSFI). The autosupported polymer matrix may consist of at least one polymer layer in which said liquid has penetrated to the core.

The polymer constituting at least one layer may be a homo- or copolymer in the form of a non-porous film capable of swelling in said liquid, or in the form of a porous film, said porous film optionally being capable of swelling in the liquid having ionic charges and whose porosity after swelling is chosen to allow percolation of the ionic charges in the thickness of the liquid-impregnated film.

The polymeric material constituting at least one layer may also be chosen from: the homo- or copolymers which do not comprise ionic charges, in which case they are borne by at least one aforementioned electroactive organic compound and / or by at least one solubilized ionic or acidic salt and / or by at least one liquid ionic or molten salt;

the homo- or copolymers comprising ionic charges, in which case additional charges making it possible to increase the rate of percolation may be borne by at least one aforementioned electroactive organic compound and / or by at least one solubilized ionic or acidic salt and / or by at least one ionic liquid or molten salt; and

mixtures of at least one homo- or copolymer not carrying ionic charges and at least one homo- or copolymer containing ionic charges, in which case additional charges making it possible to increase the percolation rate may be carried by minus an electroactive organic compound mentioned above and / or by at least one ionic salt or solubilized acid and / or by at least one ionic liquid or molten salt.

The polymer matrix may consist of a film based on a homo- or copolymer comprising ionic charges, able to give by itself a film essentially capable of providing the desired percolation rate for the electro-active system or a higher percolation rate than this and a homo or copolymer with or without ionic charges, able to give itself a film that does not necessarily ensure the desired rate of percolation but essentially able to ensure the mechanical strength, the contents of each of these two homo- or copolymers being adjusted so that they are insured at the times the desired percolation rate and the mechanical strength of the resulting self-supporting organic active medium.

The polymer or polymers of the polymer matrix not comprising ionic charges can be chosen from copolymers of ethylene, vinyl acetate and possibly at least one other comonomer, such as ethylene-vinyl acetate copolymers. (EVA); polyurethane (PU); polyvinyl butyral (PVB); polyimides (PI); polyamides (PA); polystyrene (PS); polyvinylidene fluoride (PVDF); polyether ether ketones (PEEK); poly (ethylene oxide)

(POE); copolymers of epichlorohydrin and poly (methyl methacrylate) (PMMA); and the polymer (s) of the polymer matrix bearing ionic or polyelectrolyte charges may be chosen from sulphonated polymers which have been exchanged for the ions H ⁺ of the SO ₃ H groups by the ions of the desired ionic charges, this ion exchange having occurred before and / or simultaneously with the swelling of the polyelectrolyte in the liquid comprising ionic charges, the sulfonated polymers being especially chosen from sulfonated tetrafluoroethylene copolymers, sulfonated polystyrenes (PSS), sulfonated polystyrene copolymers, poly (2 acid -acrylamido-2-methyl-1-propanesulfonic acid (PAMPS), sulfonated polyetheretherketones (PEEK) and sulfonated polyimides.

The electrically controllable device of the present invention may also have current leads to the respective layers TCC1 and TCC2 consisting of conductive strips applied to the TCC1 and TCC2 layers. The conductive strip may be a metal, an alloy or an electrically conductive composite deposited directly on the substrates covered with a conductive layer, or spacers using for example a vacuum deposition technique, or screen printing with a metal paste or welded to the substrates covered with a conductive layer or spacers or glued with an electrically conductive adhesive. The conductive strips of each substrate may be continuous or discontinuous and interconnected and may be applied to all or part of each substrate. According to a preferred embodiment of the invention, the current leads consist of continuous conductive strips applied to the layers TCC1 and TCC2 and disposed all around or substantially all around said conductive layers (TCC1 and TCC2).

The electrically controllable device of the present invention is in particular configured to form: a roof for a motor vehicle, activatable independently, or a side window or a rear window for a motor vehicle or a rearview mirror; a windshield or a portion of a windshield of a motor vehicle or an airplane or a ship, an automobile roof; an airplane porthole; a display panel of graphical and / or alphanumeric information; indoor or outdoor glazing for the building; a roof window; a display stand, store counter; a protective glazing of an object of the table type; an anti-glare computer screen; glass furniture; a partition wall of two rooms inside a building.

To better illustrate the object of the present invention will be described in more detail below two particular embodiments, with reference to the accompanying drawing.

On this drawing : - Figure 1 is a schematic view of a face of a glazing according to the first prior art;

- Figures 2 and 3 are schematic sectional views respectively II-II and III-III of Figure 1;

- Figures 4 and 5 are schematic sectional views of two variants of a glazing according to the aforementioned French patent application No. 08/58289, representing the second prior state of the cited technique;

- Figure 6 is a sectional view along VI-VI of Figure 5;

- Figures 7 and 8 are schematic views illustrating, in a comparative manner, the development of the coloring symbolized by color rectangles, respectively according to the first prior art of the technique cited above and according to the invention;

- Figures 9 and 10 are schematic views illustrating, in a comparative manner, the development of the coloring symbolized according to the second prior art of the technique cited above and according to the present invention; and

- Figure 11 is a schematic front view of an ITO layer glass implemented according to Examples 2 and 4, showing the three different regions of this layer varying according to the value of R _n . With reference to FIGS. 1 to 3, it can be seen that the glazing unit shown therein comprises two glass plates V1, V2 arranged face to face, one of which is offset downwards in order to meet the objectives of FIG. mounting in the mirror frame. The internal faces of each of these plates V ₁ , V ₂ are coated with an electronically conductive layer, respectively TCC ₁ , TCC ₂ , constituted in particular by a TCO (abbreviation of "transparent conductive oxide"). Between the two regions facing the plates V ₁ , V ₂ and coated, there is a "reservoir" zone filled with an electroactive medium EA, in solution or gelled, this reservoir being closed over its entire periphery by a gasket J encapsulation, electrical insulation.

The current leads to the respective layers TCC ₁ , TCC ₂ are made by foils respectively 1, 2, each constituted by an L-shaped metal strip, one of the branches of which is applied to the edge of the coated glass Vi, V ₂ and the other leg of which is applied against the TCC1, TCC2 layer portion, protruding from the "reservoir" portion. The foils 1, 2 are applied respectively along the upper edge and along the lower edge of the mirror. For the following explanation, the eli ⁺ compound will be chosen from 1,1'-diethyl-4,4'-bipyridinium diperchlorate (electrochromic) and, as compound ea ₂ , 5,10-dihydro-5,10 dimethylphenazine (electrochrome) or ferrocene (non-electrochromic or counter-electrode not involved in the coloring process of the system).

In an ideal system, when no voltage is applied to the device, the active medium, in which the species eai ⁺ and ea _{2 are} , is colorless, and, when a voltage is applied, the species eai ⁺ are reduced to an eal species, the latter being uniformly distributed in the vicinity of the surface of the electrically conductive layer connected to the sign pole of the electrical supply, that is to say say to the cathode of the glazing, and, similarly, the species ea ₂ oxidize in species ea ₂ ⁺ , the latter being distributed uniformly in the vicinity of the surface of the electronically conductive layer connected to the pole of sign + of the power supply, that is to say the anode of the glazing, the panel then appearing in a uniform color corresponding to the uniform mixture of species eai and ea ₂ ⁺ .

However, in reality, it appears, during the application of an electric current and during the breaking of this current, a phenomenon of segregation of phases between the pairs of species (eai, ea /) and (ea ₂ , ea ₂ ⁺ ), and especially between the species eai and ea ₂ ⁺ . This phenomenon decreases over time once the process of discoloration started or during the coloring obtained after inversion of the poles of the power supply, but which can remain for a very long time, or even still remain when it is ordered again. change of state of the electrically controllable device, so that one never obtains in this case the desired uniform colors either in the colored state or in the faded state.

This phenomenon of segregation is due to the preferential reduction of the species eai ⁺ in species eai towards the zone of greater electrical intensity of the cathode, and, conversely, to the preferential oxidation of the species ea ₂ in species ea ₂ ⁺ towards the zone of greater electrical intensity of the anode, these two zones of greater electric intensity being those of foils. The figure 6 of the accompanying drawing, the upper part schematizes a cross section of the known electrically controllable device and its lower part, a front view of the panel tensioned, illustrates this phenomenon by showing the accumulation zones of eai and ea ₂ ⁺ when the electrically controllable device is put under tension, and, consequently, the appearance of a color mainly due to the eai species towards the cathode (on the right in the front view), this color gradually degrading a new color mainly due to the species ea ₂ ⁺ to the anode (left on the front view).

The phenomenon of segregation is moreover all the more important that the panel of the electrically controllable device is larger, and currently prevents the commercial use of large electrically controllable devices, such as electrically controllable glazing for the building.

With reference to FIGS. 4 to 6, it can be seen that a glazing unit according to the French patent application No. 0858289 is shown, this latter comprising two opposing glass sheets, Vi, V ₂ , each coated of their layers respectively TTC1 and TTC ₂ separated by a spacer frame 3 in double-sided adhesive with a polyester core and closed by an outer encapsulation seal J. The frame 3 and the two coated glass sheets delimit the internal receiving space from the EA medium.

On each of the coated glass sheets, there is applied a current conducting conductive strip, which has a length 1 along a border as in the case of the prior art of FIGS. 1 to 3, but extending by three successive lengths respectively la, Ib and Ic and 2a, 2b and 2c, each in the vicinity of one of the remaining three borders. The aforementioned thin strips are folded on themselves each time by 90 ° at the corners. They are opposite the spacer frame 3, facing each other in the variant of FIG. 4 but slightly offset from one another in the variant of FIG. 5.

The assembly of the glazing and the encapsulation of the EA medium is done in a conventional manner, the current supply strips having previously been welded or glued on the periphery of the corresponding coated glass sheet.

The following Examples illustrate the present invention without however limiting its scope. In these Examples, the following abbreviations have been used:

PVDF: polyvinylidene fluoride - ITO: indium oxide doped with tin In ₂ O ₃ : Sn

- PET: Polyethylene terephthalate

The "K-glass®" glass used in the examples is a glass coated with an electroconductive layer of SnO ₂ IF (glass marketed under this name by the company "Pilkington").

The "VG40" glass used in the examples is a tinted glass having a light transmission, TL, of 54%, of the Venus Thermocontrol® range from Saint Gobain Sekurit. In order to prepare the PVDF films, the polyvinylidene fluoride powder manufactured by the company "Arkema" under the name "Kynarflex® 2821" was used.

In the Tables: - Discolored TL means the light transmission of the discolored sample after applying zero voltage for 3 minutes, averaged over the spectrum visible, ie between 380 nm and 780 nm, and measured on a Minolta 3700D spectrometer;

- colored TL means the light transmission of the colored sample after applying a voltage of 1.5V for 3 minutes, averaged over the visible spectrum, ie between 380nm and 780nm, and measured on a Minolta 3700D spectrometer

- the fading time is the time required to change from TL colored to TL colored + 90% x (TL discolored - TL colored).

- the color time is the time required to change from discolored TL to discolored TL - 90% x (discolored TL - colored TL).

EXAMPLE 1 (Comparative) Preparation of an Electrochromic Cell

K-glass ® glass with R _n = 20.5Ω / _D

Electroactive system: PVDF + ferrocene + 1,1'-diethyl-4,4'-bipyridinium diperchlorate + lithium triflate + propylene carbonate

K-glass ® glass with R _n = 20.5Ω / _D

Supply strip of welded current on K-glass ® glass over the entire periphery of each K-glass ® glass according to the configuration of Figure 6

A self-supporting PVDF film was made by mixing 6.5 g of PVDF powder, 13.0 g of dibutyl phthalate, 0.5 g of nanoporous silica and 25 g of acetone. The formulation was stirred for two hours and cast on a glass plate. After evaporation of the solvent, the PVDF film was removed from the glass plate under a net of water. The film thus obtained has a thickness of about 200 microns.

An electroactive solution was prepared by mixing 0.17 g of ferrocene, 0.37 g of 1,1'-diethyl-4,4'-bipyridinium diperchlorate and 0.28 g of lithium triflate in 30 ml of propylene carbonate. The solution was stirred for 1 hour.

The PVDF film, about 200 microns thick, was immersed for 5 minutes in diethyl ether (to solubilize dibutyl phthalate) and then for 5 minutes in the electroactive solution before being deposited on a glass plate. "K-glass ®". A second "K-glass ®" plate was deposited on the electrolyte-impregnated film, a PET frame was used as a spacer around the electro-active medium and clamps were used to ensure a good contact between the glass and the movie.

The electrochromic device thus manufactured has an active surface of 22 × 23 cm ² and its performance is reported in Table 1 below:

Table 1

EXAMPLE 2 (of the invention): Preparation of an electrochromic cell

ITO layer glass with regions of different R _n : 20, 10 and 5Ω / π, as illustrated in Figure 11 Electro-active system of Example 1

ITO layer glass with different R _{D regions} : 20, 10 and 5Ω / _{D r} as shown in Figure 11

Supply strip of welded current on K-glass ® glass, over the entire periphery of each K-glass ® glass according to the configuration of Figure 6.

A variable surface resistance ITO conductive layer was made by performing three ITO sputter deposition on the same substrate.

During the first deposit, the ITO is deposited on the entire surface of the substrate and the deposited thickness of 180nm allows to have a R _n ~ 20Ω / _D.

During the second deposit, a PET mask is used to protect the substrate with the exception of a central circle of diameter 15cm. The thickness deposited during this second deposit is 90nm, which makes it possible to reach an R _n

~ 10Ω / π at the center of the substrate.

During the third deposit, a PET mask is used to protect the substrate except for a central circle of diameter 6cm. The thickness deposited during this third deposit is 240 nm, which makes it possible to reach a

R _D ~ 5Ω / _D at the center of the substrate.

An electrochromic device having an active surface area of 22 × 23 cm ^{2 was manufactured} as described in Example 1 and the performance of which is given in Table 2 below: Table 2

EXAMPLE 3 (comparative) Preparation of an electrochromic cell

K-glas s ® glass with R _D = 20, 5Ω / _D Electro-active system: PVDF + 5, 10-dihydro-5, 10-dimethylphenazine + 1,1'-diethyl-4,4'-bipyridinium diperchlorate + Lithium triflate + propylene carbonate

K-glass ® glass with R _n = 20.5Ω / _D

An electroactive solution was prepared by mixing 0.25 g of 5,10-dihydro-5,10-dimethylphenazine, 0.50 g of 1,1'-diethyl-4,4'-bipyridinium diperchlorate and 47 g of lithium triflate in 20 ml of propylene carbonate. The solution was stirred for 1 hour. An electrochromic device having an active surface area of 22 × 23 cm ^{2 was manufactured} as described in Example 1 and the performance of which is given in Table 3 below:

Table 3

EXAMPLE 4 (according to the invention): Preparation of an electrochromic cell

ITO layer glass with R _D varying between 20, 10 and 5Ω / _D of Example 2

Electroactive system of Example 2 ITO layer glass with R _D varying between 20, 10 and 5Ω / _D of Example 2

Welded nipples all around the coated glasses

Welding current supply strip on K-glass ® glass, all around the periphery of each K-glass ® glass according to Figures 4 and 5

An electrochromic device having an active surface area of 22 × 23 cm ^{2 was manufactured} as described in US Pat. Example 1 and whose performance is given in Table 4 below:

Table 4

Claims

1 - Electrically controllable device with variable optical / energy properties, comprising the following stack of layers:

a first glass-function substrate (V ₁ );

a first electronically conductive layer (TCCi) with an associated current supply;

an electro-active system (EA) comprising or consisting of:

at least one electroactive organic compound (eai ⁺ ) capable of being reduced and / or of accepting electrons and cations acting as compensation charges; at least one electroactive organic compound (ea ₂ ) capable of oxidizing and / or ejecting electrons and cations acting as compensation charges; at least one of said electroactive organic compounds (eai ⁺ and ea ₂ ) being electrochromic to obtain a color contrast; and

a second electronically conductive layer (TCC ₂ ) with an associated current supply; and a second glass-function substrate (V ₂ ), characterized in that each of the TCC ₁ and TCC ₂ layers is chosen to have a resistance per unit of surface R _n allowing it to present an equipotential surface in coloration and discoloration, each of TCCl and TCC2 layers having a variable resistance R _n gradually decreasing from the periphery to the inside of the electrically controllable device by choosing R _n in the center of the glazing, in the or the areas furthest away from the current leads, so that the ohmic drop on the central surface of the glazing substrates, in the zone or areas furthest from the current leads, is not more than five per cent of the value the voltage applied across the device.

2 - Electrically controllable device according to claim 1, characterized in that the two layers TCCl and TCC2 opposite are identical. 3 - Electrically controllable device according to one of claims 1 and 2, characterized in that the TCCl and TCC2 layers have a variable resistance R _D gradually decreasing gradually along a gradient. 4 - electrically controllable device according to one of claims 1 and 2, characterized in that the TCCi or TCC ₂ layers have a variable resistance R _n gradually decreasing in areas.

5 - Electrically controllable device according to one of claims 1 to 4, characterized in that a conductive layer TCCi or TCC ₂ variable resistance R _n has a resistance which ranges from 20Ω / D or more peripherally to 5Ω / D or less in the center of the layer.

6 - Electrically controllable device according to one of claims 1 to 5, characterized in that a layer

TCCi or TCC ₂ is in the form of a continuous layer or in the form of a grid or a microgrid or in the form of grids or a microgrid coated with a continuous layer.

7 - Electrically controllable device according to one of claims 3 and 5, characterized in that a TCCi or TCC ₂ layer with variable resistance R _n , has been obtained by plasma treatment, flame or ablation of material of said layer to progressively degrade the conductivity or degrade it by zones; by deposits, in particular under vacuum, successive conductive material on the glass substrate, the first deposit being made on the entire surface of the substrate, then the subsequent deposit being made on a central region thereof with masking of the region periphery, and so on if other zones must be formed, the deposits other than the first being able to be made in particular on circular regions so that the different zones of the layer are concentric zones, the center of which corresponds to that of the substrate; by a network of identical or different conductive and / or insulative patterns, which have been formed on at least a portion of the conductive layer deposited on the substrate.

8 - electrically controllable device according to one of claims 1 to 7, characterized in that the electronically conductive layers TCC1 and TCC ₂ are metal-type layers, such as layers of silver, gold, platinum and copper; or transparent conductive oxide (TCO) layers, such as tin - doped indium oxide (In ₂ O ₃ : Sn or ITO) layers, antimony - doped indium oxide ( In ₂ O ₃ : S _b ), fluorine-doped tin oxide (SnO ₂ : F) and zinc oxide doped with aluminum (ZnO: Al); or TCO / metal / TCO multilayers, the TCO and the metal being in particular chosen from those enumerated above; or multilayer type NiC _r / metal / NiC _r , the metal being in particular chosen from those listed above.

9 - Electrically controllable device according to one of claims 1 to 8, characterized in that the TCCl & TCC2 layers are each connected to a current supply constituted by a conductive strip applied to the associated TCCl or TCC2 layer, the conductive strip can be a metal, an alloy or an electrically conductive composite which is deposited directly on the substrate covered with its conductive layer or on a spacer separating the two spacer substrates, for example using a vacuum deposition technique or screen printing with a metal paste, or which is welded onto the substrate covered by its conductive layer or on a spacer separating the two substrates or which is adhered by an electrically conductive adhesive, the conductive strip applied to a substrate which can be continuous or have discontinuous and connected regions between them and can be applied to all or part of each ubstrat.

10 - Electrically controllable device according to claim 9, characterized in that the current leads consist of continuous conductive strips applied to the TCCl and TCC2 layers and disposed around the entire periphery or substantially all around said conductive layers (TCCl and TCC2 ).

11 - Electrically controllable device according to one of claims 1 to 10, characterized in that the substrates with glass function are selected from glass and transparent polymers, such as poly (methyl methacrylate) (PMMA), polycarbonate

(PC), poly (ethylene terephthalate) (PET), poly (ethylene naphthoate) (PEN) and copolymers of cycloolefins (COC).

12 - electrically controllable device according to one of claims 1 to 11, characterized in that between a substrate with a glass function, in particular a plastic substrate, and a TCCl or TCC2 layer is arranged a layer or a stack of layers this layer or layers being chosen independently from inorganic, organic or organic-inorganic hybrid layers, and having been deposited on the substrate before the deposition of the associated TCC1 or TCC2 layer, in particular in order to improve the adhesion of TCCl or TCC2 on the substrate or to provide an additional function such as impermeability to gases and moisture. 13 - electrically controllable device according to one of claims 1 to 12, characterized in that the electro-active system (EA) comprises a self-supporting polymer matrix in which are inserted the electro-active organic compound (s) (eai ⁺ & ea ₂ ) and the ionic charges, said polymer matrix containing within it a liquid (L) solubilizing said ionic charges but not solubilizing said self-supporting polymer matrix, the latter being chosen to ensure a percolation path of the ionic charges to allow said reactions to occur. oxidation and reduction of said electroactive organic compounds (eai ⁺ & ea ₂ ), the ionic charges being borne by at least one of said electroactive organic compounds (eai ⁺ & ea ₂ ) and / or reduced and oxidized species which are respectively associated with them (eai ⁺ ea ₂ ⁺ ) by at least one ionic salt and / or at least one acid solubilized in said liquid (L) and / or by the self-supporting polymer matrix; the liquid (L) being constituted by a solvent or a mixture of solvents and / or by at least one ionic liquid or molten salt at ambient temperature, the said ionic liquid or molten salt or the said ionic liquids or molten salts then constituting a liquid (L ) carrying ionic charges, which represent all or part of the ionic charges of said electro-active system.

14 - electrically controllable device according to one of claims 1 to 12, characterized in that the electro-active system comprises a solution or a gel containing the electroactive organic compounds (eai & ea ₂ ).

15 - Electrically controllable device according to one of claims 1 to 14, characterized in that the electroactive organic compound (s) (eai) is or are chosen from bipyridiniums or viologenes such as 1,1'-diethyl diperchlorate 4, 4'-bipyridinium, pyraziniums, pyrimidiniums, quinoxaliniums, pyryliums, pyridiniums, tetrazoliums, verdazyls, quinones, quinodimethanes, tricyanovinylbenzenes, tetracyanoethylene, polysulfides and disulfides, and all the electro-active polymeric derivatives of the electro-active compounds which have just been mentioned; and the electroactive organic compound (s) (ea ₂ ) is or are chosen from metallocenes, such as cobaltocenes, ferrocenes, N, N, N ', N' -tetramethylphenylenediamine (TMPD), phenothiazines such as phenothiazine, dihydrophenazines such as 5,10-dihydro-5,10-dimethylphenazine, reduced methylphenothiazone (MPT), methylene violet bernthsen (MVB), verdazyls, and all polymeric derivatives electroactive compounds of the electroactive compounds which have just been mentioned.

16 - Electrically controllable device according to claim 13, characterized in that: the ionic salt or salts are selected from lithium perchlorate, trifluoromethanesulfonate or triflate salts, trifluoromethanesulfonylimide salts and ammonium salts; the acid or acids are chosen from sulfuric acid (H ₂ SO ₄ ), triflic acid (CF ₃ SO ₃ H), phosphoric acid (H ₃ PO ₄ ) and polyphosphoric acid (H _{n + 2} P _n 0 _{3n +} 1); the solvent or solvents are chosen from dimethylsulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, propylene carbonate, ethylene carbonate, N-methyl-2-pyrrolidone (1-methyl-2- pyrrolidinone), gamma-butyrolactone, ethylene glycols, alcohols, ketones, nitriles and water; the ionic liquid or liquids are chosen from imidazolium salts, such as 1-ethyl-3-methylimidazolium tetrafluoroborate (emim-BF ₄ ), 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (emim-CF ₃ SO ₃ ) 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (emim-N (CF ₃ SO ₂ ) ₂ or emim-TSFI) and 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (bmim-N ( CF ₃ SO ₂ ) ₂ or bmim-TSFI).

17 - Electrically controllable device according to one of claims 1 to 16, characterized in that it configured to form: a roof for a motor vehicle, activatable autonomously, or a side window or a rear window for a motor vehicle or a rear-view mirror ; a windshield or a portion of a windshield of a motor vehicle or an airplane or a ship, an automobile roof; an airplane porthole; a sign displaying graphical and / or alphanumeric information; indoor or outdoor glazing for the building; a roof window; a display stand, store counter; a protective glazing of an object of the table type; an anti-glare computer screen; glass furniture; a partition wall of two rooms inside a building.