Nissan Motor Company Limited

Harutoshi Miyagi

Masazumi Ishikawa

Mikio Kawai

Yasuyuki Murofushi

Teruko Yoshimoto

Mikio Ura

The invention relates to a nonglaring mirror which is an electrochromic (EC) device in principle. The mirror comprises a transparent front substrate provided with a transparent first electrode layer, a back substrate provided with a second electrode layer opposite to the first electrode layer, first and second EC layers formed on the first and second electrode layers, respectively, an electrolyte liquid which fills up the space between the two substrates and reflecting means for providing a reflective surface to the second substrate. The material of the first EC layer is an organic polymer which is colorless or very pale in color in its electrochemically reduced state and undergoes electrochemical oxidation in two stages to assume a characteristic color in the first-stage oxidized state and another color in the second-stage oxidized state, and intermediate colors in intermediately oxidized states. It is very favorable to use a polymer made up of repeating structural units of N,N,N',N'-tetraphenyl-p-phenylenediamine. The second EC layer is usually formed of a transition metal oxide, e.g. WO.sub.3, which takes on color in its electrochemically reduced state.

Electrochromic variable color tone nonglaring mirror

The invention relates to a variable light transmittance glass board which is an electrochromic cell in principle and is comprised of oppositely arranged two transparent glass substrates each of which is laid with a transparent electrode film, first and second electrochromic layers formed on the two electrode films, respectively, by using tungsten trioxide for the first layer and Prussian blue for the second layer and an electrolyte liquid which fills up the space remaining between the two electrode films. The electrolyte liquid is a solution of a conventional supporting electrolyte such as lithium perchlorate in an organic polar solvent such as propylene carbonate. Durability of both electrochromic layers at elevated temperatures is greatly improved by adding 0.2-3.0 wt % of water to the organic polar solvent. By using one or two auxiliary electrode(s) comprising an electrochemically oxidizable and reducible material and being disposed in a marginal region of the space between the two glass substrates, it is possible to prevent the appearance of the glass board from being marred by partial decomposition of the electrolyte liquid at the initial reduction of one electrochromic layer. A polymer of a conjugated compound, e.g. polytriphenylamine, is very advantageous as the electrochemically active material in each auxiliary electrode.

Variable light transmittance glass board functional as electrochromic

The invention relates to an electrochromic (EC) device having oppositely arranged two substrates at least one of which is transparent and each of which is coated with an electrode film on the inside surface, a first EC layer which is formed on the electrode film of one substrate and is formed of a transition metal oxide that takes on color in its electrochemically reduced state, such as WO.sub.3, an opposite EC layer which is formed on the electrode film of the other substrate and is formed of another EC material, such as a polytriphenylamine that takes on color in its electrochemically oxidized state, and an electrolyte solution which uses a nonaqueous solvent and occupies the space between the two substrates. According to the invention, the transition metal oxide layer contains such an amount of adsorption water that the concentration of water in the electrolyte solution in the device becomes more than 0% and not more than 0.3% by weight. This is effective for enhancement of the durability of the transition metal oxide layer and also for improvements in the response characteristics of the metal oxide layer as an EC layer. The transition metal oxide layer is formed as a film by a usual deposition technique and then is immersed in a solution of an electrolyte in an organic solvent containing a suitable amount of water, which is usually not less than 0.5 vol % and not more than 30 vol %.

Electrochromic device using transition metal oxide and method of

Disclosed is a nonglaring mirror which is an electrochromic device in principle. The mirror comprises a transparent front substrate laid with a transparent first electrode film, a back substrate laid with a second electrode film which is opposite and spaced from the first electrode film, first and second electrochromic layers formed on the first and second electrode films, respectively, and an electrolyte liquid which fills up the space between the two substrates. A reflecting surface is provided by using a transparent sheet as the back substrate and coating the rear surface of the back substrate with a reflecting metal film, or by using a reflecting metal film as the second electrode film. One of the first and second electrochromic layers is formed of a polymer of a conjugated compound, such as substituted or unsubstituted triphenylamine, and the other is formed of a transition metal oxide such as WO.sub.3. In the initial state both the first and second electrochromic layers are colorless and transparent. For coloration, the conjugated polymer layer is oxidized and the transition metal oxide layer is reduced. In the colored state the reflectance of the mirror becomes 7-15% and is controllable.

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Yokohama, Japan

Harutoshi Miyagi