BACKGROUND OF INVENTION Electrochromic mirrors, particularly for motor vehicles, are known in the state of the art. The essential element of these electrochromic mirrors is a layer of electrochromic material. A material is termed electrochromic when it changes its optical constants (n, k) and hence its optical properties on application of an electric field. Typical examples of such electrochromic materials are W03 and MoO3, which are virtually colourless when applied to a substrate in thin layers. An electrochromic layer may change its optical properties by oxidation or reduction pro- cesses. If protons move in such a layer, in the case of tungsten oxide there is a reduction to blue tung- sten bronze. The intensity of colouration is deter- mined by the quantity of charge which has flowed in the layer. R Numerous electrochromic mirrors, particularly for motor vehicles, are now know from the state of the art and have electrochromic layers of this type in different layered structures.

German 3 008 768 describes an electrochromic mirror which essentially consists of a layer system built on

a glass substrate at least one electrochromic layer, at least two electrodes, at least one proton-conduct- ing layer and at least one proton-delivering and one proton-storing layerbeing present.

The optical change properties of a mirror of this type are determined, inter alia, by the proton con- ductivity of the proton-conducting layer. The higher the proton conductivity, the higher also the rate of change of reflection. In the mirrors of the state of the art, proton-conducting glass plates, which were soaked with sulphuric acid, have been used hitherto as proton-conducting layers (for example in German Offenlegungsschrift 2 504 905) or as in German 3 008 768 so-called aolid ion-conducting layers.

It has been shown all these ion-conducting layers from the state of the art used hitherto for the electrochromic glass components atill do not have satisfactory results with regard to ion conductivity.

Furthermore, it is disadvantageous for the mirrors of the state of the art, that the ion-conducting layers described there are either too thick or are too com- plex and expensive as regards their mode of manufac- ture.

SUMMARY OF INVENTION The object of the present invention is therefore, starting from the electrochromic mirror as described in german 3 008 768, to indicate a significantly improved embodiment which is characterised partic- ularly by an ion-conducting layer which is favourable to apply as regard to manufacture and processing and furthermore has a high ion conductivity, with which

it is possible to change the electrochromic layer quickly.

The invention is achieved by the characterising fea- tures of patent claim 1. The sub-claims show advan- tageous further developments.

According to the invention it is thus propose to use a doped ion-conducting basic polymer as the ion-con- ducting layer. It has been shown that these doped ion-conduction basic polymers are particularly well suited. The doped ion-conducting basic polymer is preferably selected from polybenzimidazoles (PBI), polypyridines, polyimidazolea, polybenzthiazolea, polybenzoxazoles, polyquinolines, polythiazoles, polyoxadiazoles and polytetrapyrenes. The ion-con- ducting layer ia thus a layer which preferably con- ducts protons. However, in principle the layer is also suitable for other ions, such as for example lithium.

DESCRIPTION OF THE DRAWINGS The invention is illustrated in more detail below using Figure 1 and Figure2.

Figure 1 shows an electrochromic glass component of the invention, here as a motor vehicle mirror.

Figure 2 shows the concrete structure of a mirror.

DESCRIPTION OF THE INVENTION The electrochromic glass component, which is used as a motor vehicle mirror, consists of a glass substrate

1 having a thickness oi 2 mm. A layer system which has the following successive layers is applied to this substrate 1.

An electrochromic layer 2 of tungsten oxide having a thickness of-700 nm, a mirror layer 3 of palladium having a thickness of-70 nm, a polymer membrane 4 of polybenzimidazols polymer having a thickness of 30 gm, a proton store 5 of tungsten trioxide having a thickness of 700 nm, a rear electrode 6 of gold hav- ing a thickness of 100 nm, a polyester film 7 having a thickness of about 175 gm as well as a sealing lay- er 8 of traditional plastics, which wraps around the entire coating system including the glass substrate 1 and thus seals the coating system comprising layers 2 to 7. Seal 8 is only interrupted by copper wires 5, which contact the mirror layer 3 on the one side and the rear electrode 6 on the other side to apply a voltage to the latter.

Figures 2a and 2b show the electrochromic glass com- ponent according to Figure 1, but the function of a glass component of this type becomes visible here. In the exemplary embodiment according to Figure 2, a primer 10 for better adhesion promotion is also applied between the electrochromic layer 2 and the mirror layer 3. Figure 2a thus shows the light posi- tion and Figure 2b the dark position.

It ia particularly preferable for the electrochromic glass component of the invention if the doped ion- conducting polymer is present in the form of a poly- mer membrane. A proton-conduction polymer membrane particulate preferred. It should be emphasised in particular for the ion-conducting layer according to

the invention that it may be applied easily using all conventional techniques. Examples of these are screen printing, immersion, spraying, blade coating or also application of a gel.

According to the present invention it is particularly preferable if the polymer membrane is a polybenzimidazole.

It should be emphasised in particular for the electrochromic glass component of the invention that the doped ion-conducting layer has particularly good properties with regard to its ion conductivity if the ion-conducting layer is doped with an acid, in par- ticular with a strong acid. It is preferable if the pKa value of the doping acid s 4.5, preferably s 3. 5 for the first dissociation stage at 25 °C. For acid it has proved to be particularly advantageous if the acid is a phosphoric acid, in particular a poly- phosphoric acid. Acid treatment of polybenzimidazoles is described in United States 5 599 639, to which reference is made expressly here.

It is particularly preferable for the electrochromic glass component of the invention if it contains a proton-conducting polymer membrane of polybenzimidazole.

Polymer membranes of this type, which are composed of polybenzimidazoles and are proton-conducting, are known from the state of the art, for example from United States 5 017 681. All named polybenzimidazoles in the above-mentioned United States patent specifi- cation may be used in principle for the proton-con- ducting layer of the invention. It is particularly

preferable if the polymer consists of a polybenzimidazole having a molecular weight between 1,000 and 500,000 which consists of repeating units of the following structural formula: It has proved to be particularly favourable for the electrochromic glass component if the ion-conducting layer described in more detail above is used at a layer thickness of 1 ym to 1 mm, preferably 5 ym to 100 ym. Application of the layer, in particular the polymer membrane, may thus be effected by screen printing, immersion, spraying, blade coating or even as a gel. Provision is thus made according to the invention in that the layer is applied either as a finished film or is even produced directly on the substrate or a layer lying underneath. These applica- tion procedures may also be used in combination.

The electrochromic layer, which preferably has a lay- er thickness of 300 nm to 8,000 nm, preferably 300 nm to 8,000 nm, preferably consists of W03, Mo03, IrO2 or mixed oxides thereof. The electrochromic layer is applied by sputtering, sol-gel or by vapour deposi- tion.

The electrodes, which are necessary for constructing the layer system of the invention, are preferably

metallic layers having a layer thickness of 50 nm to 10 m. Examples oS layers of this type are those which contain rhodium, palladium. platinum or alloys thereof.

According to a preferred embodiment, provision is made in that a metallic electrode layer at the same time forms a reflector which may accept protons This reflector preferably consists of a layer having a layer thickness of 30 nm to 500 nm, which contains rhodium, palladium, platinum or alloys thereof.

As already described in German 3 00B 768, it is also preferable for the electrochromic glass component of the invention if the ion-delivering layer and the ion-storing layer at the same time form a layer or a composite. According to a preferred embodiment of the invention, provision is thus made in that the proton- storing layer is the electrochromic layer at the same time. In this case, for example a W03 layer, thus functions at the same time as a hydrogen ion-storing layer and as an electrochromic layer. According to a preferred embodiment, the composite consists of the proton-storing and at the same time proton-delivering layer on a film, preferably a polyester film with metallisation which is the counter-electrode. Instead of the film of polyester, glass, metal or other plas- tics are suitable as substrate materials for the com- posite.

With regard to the possible layered structure vari- ants of the electrochromic glass component of the invention, reference is made to German 3 008 768 and the layered structure described therein.

However, it is preferable for the glass component of the invention if the glass component has been con- structed from two layered composites. Hence, in the manufacture of the electrochromic glass component according to a preferred embodiment, a first layer system is constructed on a glass substrate, an electrochromic layer applied thereto and metallisation as a reflector. These layers are pro- duced by means of sputtering processes.

The second part of the layer system is then a compos- ite which consists of a proton-storing layer, metallisation and a film arranged thereabove, in par- ticular a polyester film. This composite is manufac- tured in a separate process step and then joined to the above-mentioned first layered composite of the layer system. This procedure facilitates cost-effec- tive and simple manufacture of the electrochromic glass component.

A further favourable embodiment of the invention makes provision, if it is necessary, in that adhesion-promoting layers for better bonding are applied between the individual layers. Examples of this are chromium, titanium or even silicon oxides SiO. For application as motor vehicle mirrors, pro- vision is also made in that the layer system is tightly aealed externally. Hence the layer system may be sealed at the and-faces and a final layer, that is a layer opposite the glass substrate seen in the viewing direction, may be provided with a protective layer, for example a diffusion barrer. Diffusion barries of this type have a water permeability c 1,000, preferably c 100 cm3. For motor vehicle mir- rors it has proved to be particularly favourable if

the glass substrate is a reflection-reducing thin glass having a layer thickness of 0,1 to 3 mm. For motor vehicle mirrors it is also advisable if a transparent conductive layer for heating the mirror is applied in front of the substrate, seen in the viewing direction.