Electrochromic display device
US4850684A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 28, 1987 |
| Grant date | Jul 25, 1989 |
| Priority date | — |
| Expiry date | May 28, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/1533
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention relates to an electrochromic (EC) display device which comprises a display electrode made up of a transparent conductive layer and a patterned EC layer, a counter electrode having an EC layer laid on a conductive layer and an electrolyte which occupies the space between the two electrodes, and in which the display electrode employs a first type EC material that takes on color in its electrochemically oxidized state, such as Prussian blue, and the counter electrode a second type EC material that takes on color in its reduced state, such as WO.sub.3, or vice versa. The EC layer of the counter electrode is not patterned, and the patterned EC layer of the display electrode is made smaller in surface area than the EC layer of the counter electrode and an upper limit of the surface area ratio of the former EC layer to the latter EC layer is specified. WHen this EC display device is driven in the usual manner coloration of the patterned EC layer takes place without perceptible coloration of the EC layer of the counter electrode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.