Electrochemical display element and electrochemical display

Abstract

An electrochemical display device and an electrochemical display apparatus, having preferable cycle properties and preferable display quality, and a method for producing the same. The electrochemical display device according to the present invention is characterized in that it has: a first transparent electrode; an electrolyte layer containing a coloring material which colors by a coloring means and electrochemical reduction or oxidation, accompanied by deposition or dissolution; a second electrode having the electrolyte layer disposed between the first transparent electrode and the second electrode; and a third electrode independent of the first transparent electrode and the second electrode.

Description

TECHNICAL FIELD [0001] The present invention relates to an electrochemical display device using a principle such that the color of a material is changed utilizing electrochemical oxidation or reduction. BACKGROUND ART [0002] In recent years, as the network widely spreads, documents, which have conventionally been delivered in the form of prints, are being delivered in the form of so-called electronic documents. Further, books, magazines and the like are frequently provided through so-called electronic publication. [0003] The information has been read conventionally from a CRT or liquid crystal display of a computer. However, it is pointed out that a light emission type display causes severe fatigue for the reasons of ergonomics, making long-time reading difficult. In addition, there is a drawback in that information can be read only at the place in which a computer is located. [0004] Laptop computers widely spread currently, and some of them are used as portable display, but they ca...

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Benefits of technology

[0011] In the electrochemical display device according to the present invention having the above configuration, by virtue of having the third electrode independent of the first transparent electrode and the second electrode, the reaction state during the deposition or dissolution of the coloring material is precisely detected without being affected by the first transparent electrode and second electrode. Therefore, a point in time when the deposition or electrochemical reaction satisfactorily proceeds at the electrode is precisely detected, and driving is controlled based on the result of detection, achieving precise control of the driving. In addition, the precise control of the driving prevents the reaction from proceeding to an excess extent, so that the occurrence of a side reaction due to the excess reaction is prevented.

[0013] In the electrochemical display apparatus according to the present invention having the above configuration, the electrochemical display device constituting the electrochemical display apparatus has the third electrode independent of the first transparent electrode and the second electrode, and hence the reaction state during the deposition or dissolution of the coloring material is precisely detected without being affected by the first transparent electrode and second electrode. Therefore, a point in time when the deposition or electrochemical reaction satisfactorily proceeds at the electrode is precisely detected, and driving is controlled based on the result of detection, achieving precise control of the driving. In addition, the precise control of the driving prevents the reaction from proceeding to an excess extent, so that the occurrence of a side reaction due to the excess reaction is prevented.

[0015] In the above method for producing an electrochemical display device according to the present invention, the third electrode independent of the first transparent electrode and the second electrode is formed, and therefore a device is produced in which the reaction state during the deposition or dissolution of the coloring material is precisely detected without being affected by the first transparent electrode and second electrode. Thus, there is produced an electrochemical display device advantageous in that driving is precisely controlled to prevent the occurrence of a side reaction due to the excess reaction.

[0017] In the above method for producing an electrochemical display apparatus according to the present invention, the third electrode independent of the first transparent electrode and the second electrode is formed when forming an electrochemical display device, and therefore a display apparatus is produced in which the reaction state during the deposition or dissolution of the coloring material is precisely detected without being affected by the first transparent electrode and second electrode. Thus, there is produced an electrochemical display apparatus advantageous in that driving is precisely controlled to prevent the occurrence of a side reaction due to the excess reaction.

Problems solved by technology

However, it is pointed out that a light emission type display causes severe fatigue for the reasons of ergonomics, making long-time reading difficult.

In addition, there is a drawback in that information can be read only at the place in which a computer is located.

Laptop computers widely spread currently, and some of them are used as portable display, but they cannot be used in reading for several hours or longer because they are of a light emission type using a back light and further consume the power soon.

Recently, a reflection type liquid crystal display is developed, and the use of this enables driving of a computer with low power consumption; however, the liquid crystal has only a reflectance of plain display (white display) as low as 30%, and hence has markedly poor visibility, as compared to printed paper, and is likely to cause fatigue, thus also making long-time reading difficult.

However, these methods have disadvantages in that spaces between the particles absorb a light to lower the contrast, and the driving voltage required for obtaining a practical writing speed (1 second or faster) is as high as 100 V or more.

However, the photochromic glass and clock display essentially have no need of matrix driving, and hence cannot be applied to display use of electronic paper, and they generally have poor black quality and low reflectance.

However, an organic material generally has poor light resistance and hence poses a problem in that black color is faded and the black density is lowered after being used for a long time.

However, the properties, especially cycle properties are unsatisfactory, and it is desired that the cycle properties are improved.

In addition, there is a problem in that appropriate control of the oxidation reduction reactions is not satisfactorily achieved and the image remains upon display switching, that is, afterimage is caused, thus lowering the image quality.

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