Electrically-controllable device with variable optical and/or energy properties

Electrically controllable device with variable optical and / or energy properties

The invention relates to electrically controllable devices with variable optical and / or energy properties. He is more particularly interested in devices that use electrochromic systems, which operate in transmission or reflection.

Examples of electrochromic systems are described in patents US-5,239,406 and EP-612,826.

As for US-A-4,488,780, an example of an electrochromic system according to the preamble of claim 1 is described.

The electrochromic systems have been very studied. They generally have two layers of electrochromic materials generally separated by an electrolyte and framed by two electrodes. Each of the electrochromic layers, due to the effect of a power supply, can reversibly insert charges, modifying its degree of oxidation following these insertions / disinsertions that lead to a modification of its optical and / or thermal properties (for example , by tungsten oxide, a step from a blue color to a colorless appearance).

It is usual to classify electrochromic systems into three categories:

<dl><dt>-</dt><dd>one in which the electrolyte is in the form of a polymer or a gel; for example a proton conduction polymer such as those described in patents EP-253,713 or EP-670,346, or a lithium ion conduction polymer such as those described in patents EP-382,623, EP-518,754 and EP-532,408, wherein the other layers of the system are generally mineral in nature; -one in which the electrolyte is an essentially mineral layer. This category is often referred to with the term "all-solid" system, and examples thereof can be found in EP-867,752, EP831,360, in French patent application FR-2,791,147, and in French patent application FR-2,781,084; -one in which the set of layers is based on polymers, a category that is often referred to by the term "all-polymer" system.</dd></dl>

Many applications have already been planned for these systems. It is, more generally, to use them as glazing for the building or as glazing for vehicles, especially for car roofs, or even, which then work in reflection and not in transmission, as anti-glare mirrors.

However, for all these applications, due to their sensitivity with respect to environmental aggressions, electrically controllable devices are generally not inserted in these conditions inside a substrate, but are protected within a sheet substrate that also incorporates at least one interleaving of foliation, which is generally a polymer film.

This polymer film may eventually have an antisolar function that is intended to protect the electrochromic system layers from eventual heating due to infrared radiation. In another configuration the antisolar function refers to the stacking layers of the electrochromic system.

However, whatever the origin of the antisolar function, the reliability of the electrochromic systems that can be experienced for example in terms of the durability of the switching cycles between a color state and a state of discoloration of the active layers depends of the temperature, and of any temperature variation (in particular an increase in the temperature of the active layers as a result of intense exposure to infrared radiation (electrochromic roof in full sun)) leads to an increase in the speed of degradation of said layers. active layers.

Classically, this antisolar function is carried out by means of an anti-reflective coating that is usually constituted by a stack of interferential thin layers, in general an alternation of layers based on a dielectric material, based on metallic oxide, especially of the oxide, nitride or oxinitride type of metals, with large and small refractive indexes.

Although it does not respond perfectly to its role of protection of the active layers of the electrochromic system with respect to infrared radiation, the antisolar layer that is eventually incorporated into the foliar interleaving must also withstand mechanical stresses as a result of foliation.

These tensions are all the more serious when the substrate when the sheet substrate has a complex profile (substrate with an important arrow in at least one direction, such as a double-domed substrate).

The present invention aims to alleviate these drawbacks by proposing an electrically controllable device that incorporates at least one polymer film that is adapted to complex substrate profiles.

The object of the invention is therefore an electrically controllable device with variable transmission / reflection optical / energy properties, such as that described in claim 1.

The invention will be described in more detail with respect to the drawings, in which:

<dl><dt>-</dt><dd>Figure 1 is a schematic view of an electrically controllable device according to the invention, Figure 2 gives the position of the different points necessary for the calculation of the complexity factor F. </dd></dl>

In the accompanying drawings certain elements can be represented with dimensions larger or smaller than in reality in order to facilitate the understanding of the figures.

Figure 1 represents a glass 1 provided with a lower conductive layer 2, an active stacking 3, an upper conductive layer 4 above, a first network of conductive wires 5 or an equivalent device that allows the electric current to be fed over of the upper conductive layer, of a second network of conductive wires 6 or of an equivalent device that allows an electric current to be supplied below the lower conductive layer 2. The power supplies are either conductive wires if the electrochromic active layer is sufficiently conductive, or a network of wires that go over or into a layer that forms an electrode, which is metallic or of the TCO (Transparent Conductive Oxide) type in ITO, SnO2: F, ZnO: Al, or just a conductive layer.

The conductive wires 5, 6 are metallic wires for example of tungsten (or copper), possibly coated with carbon, with a diameter between 10 and 100 μm and preferably between 20 and 50 μm, rectilinear or corrugated, arranged on a polymer sheet by a technique known in the field of windshields heated with wires, described for example in patents EP-785,700, EP-506,521, EP-496,669.

One of these known techniques consists in the use of a heated pressure roller that presses the thread on the surface of the polymer sheet, and said pressure roller is fed with thread from a feeding coil thanks to a guiding device of the thread

A lower conductive layer 2 is a double layer formed by a first 50 nm SiOC layer with a second layer above 400 nm SnO2: F (two layers preferably placed successively by CVD on the float glass before being cut).

Alternatively, it can be a double layer formed by a first layer based on SiO2 doped or not (especially doped with aluminum or boron) of approximately 20 nm with a second layer above ITO of approximately 100 to 350 nm (two layers preferably deposited successively in vacuum by sputtering assisted by a magnetic and reactive field in the presence of oxygen, if hot).

The upper conductive layer is an ITO layer of 100 to 300 nm, also deposited by reactive sputtering assisted by a magnetic field on the active stack, which is carried out analogously to the lower conductive layer 2.

The active stack 3 shown in Figure 1 decomposes as follows:

! a first layer of iridium oxide (hydrated) anodic electrochromic material Ir0xHx from 40 to 100 nm, (it can be replaced by a layer of hydrated nickel oxide), alloyed or not with other metals; ! a 100 nm tungsten oxide layer; ! a second layer of hydrated tantalum oxide or hydrated silicon oxide or zirconium oxide 100 nm hydrate; ! a second layer of a 370 nm tungsten oxide cathode electrochromic material based on 370 nm; This stack 3 is particularly stable, especially against UV rays, and works by insertion of lithium (Li +) ions or alternatively of H + ions.

The stack 3, the upper conductive layer and the lower conductive layer and the current feeds embedded in the surface of a polymer sheet f are deposited on the inner face of a first substrate. The glazing also has a second substrate above the polymer sheet. The two substrates and the polymer sheet are made solidary by a known technique of foliation or calendering by eventually heating under pressure.

The polymer sheet f is a birefringent dielectric multilayer film that reflects at least 50% of the light in a band of at least 100 nm in width in a spectral zone of interest and capable of adopting the shape of a domed substrate by effect of a uniform contraction.

This film is marketed under the “SRF” brand by the 3M company and forms a multilayer based on PET / coPMMA approximately 50 μm thick.

According to one characteristic of this film, it has a contraction rate clearly more important than that of the other polymer films that also have an antisolar function.

By way of comparison, below are the values ​​of the contraction rates after a heat treatment at 130 ° C for 1 hour.

These values ​​are compared with that of a traditional PET film marketed by the Southwall company that incorporates an antisolar coating.

For this film, the contraction values ​​are between 0.25% and 0.45%. For the film marketed by the 3M company, the contraction values ​​are between 0.8% and 1.5% for standard manufacturing, and between 1.6% and 4%, preferably between 1.9% and 2, 2% for a special manufacture that has been developed for the needs of the invention.

In the sense of the invention, the parameter F has been defined which allows characterizing the complexity of a glazing that incorporates the polymer film, for example that developed by the 3M company.

Parameter F is calculated as follows:

HY HZ

00 00

F ∀ x

CY0 CZ0

Reference can be made to the graph given in Figure 2 for the spatial situation of the various points mentioned in this formula.

This polymer film is integrated into a sheet substrate whose complexity F value is between 0.00215 and 0.00240 and preferably between 0.00219 and 0.00230.

The set of the three parts makes an electrically controllable device with variable optical and / or energy properties whose electrochromic material is protected from the outside, thereby increasing the service life of the electrically controllable device. The polymer film is specially adapted to protect the layer of functional material (electrochromic for example) from impacts, especially of gravels that can lead to a crashed state of the substrate. On the other hand, it can be seen that the polymer film constitutes a moisture barrier that effectively retards deterioration in terms of the impacts caused by the gravels.

On the other hand, the two glasses that form the electrically controllable device substrates described above are of a clear, normal, silico-sodium-calcium flat glass of approximately 2 mm thickness each, where at least one can be dyed in bulk. .

Therefore, an embodiment of the invention is constituted as follows: Glass (2.1 mm) / PU (0.76 mm) / polymer film / PU (0.76 mm) / functional layer / Gray Glass (2.1 mm).

When this functional layer is the previously intended electrochromic system, the measurements give:

<dl><dt>-</dt><dd>&gt; Colored state: </dd></dl>

TL = 1.1%; a * = - 2; b * = -1.4; TE = 0.7%; RE = 22%

<dl><dt>-</dt><dd>&gt; Discolored state: </dd></dl>

TL = 18%; a * = - 6; b * = 7; TE = 10%; RE = 21%

In this assembly configuration the polymer film has dimensions smaller than those of the substrates between which it is integrated, the polymer film follows the contours of the screen printing such that the edges of the film are embedded in the points of Screen printing. This configuration allows to achieve even higher values ​​of bulge complexity (of F).

The invention is applied in the same way to domed and / or tempered glass.

Likewise, at least one of the glasses can be tinted in mass, especially tinted blue or green, gray, bronze or brown.

The substrates used in the invention can also be polymer based (PMMA, PC ...). It is also observed that the substrates can have very varied geometric shapes: they can be squares or rectangles, but also any at least partially curved polygon or profile, defined by rounded or wavy contours (round, oval, "waves", etc.). .).

On the other hand, at least one of the two glasses (on the face that is not provided with the electrochromic system or equivalent) may be covered by a coating that has other functionality (this other functionality may be, for example, an antisolar stack, a anti-dirt stacking or other). As antisolar stacking it can be a stacking of thin layers deposited by sputtering and comprising at least one

10 silver cape You can thus have some combinations of the type

! glass / electrochromic system / antisolar layers / glass. ! glass / electrochromic system / glass / thermoplastic / glass. ! glass / electrochromic / thermoplastic system / glass.

fifteen ! glass / thermoplastic / electrochromic system / thermoplastic / glass.

In this way, the antisolar coating can be deposited not on one of the glasses but on a thin polymer sheet of the PET type (polyethylene ethylhetalate).

twenty For examples of antisolar coatings, reference may be made to patents EP 826.641, EP 844.219, EP 847.965, WO99 / ​​45.415 and EP 1.010.677.

The device object of the invention described above can also be integrated into a triple glass "substrate", the latter being advantageously usable in the production of glazing according to the

25 security requirements

On the other hand, it can be seen that the electrically controllable device such as the one described above has the advantage of being transparent to electromagnetic waves.

30 Indeed, these electrically controllable devices that incorporate electrochromic and antisolar functionalities are increasingly used in the automobile field, a field that often requires transparency to electromagnetic waves (portable telephone, various remote controls, automatic payment systems on barriers toll ...).