Electrochromic device

Details Electrochromic device Electrochromic device

2000-06-19

2003-03-25

Jones, Deborah (Department: 1774)

Optical: systems and elements

Optical modulator

Light wave temporal modulation

C359S270000, C359S272000, C359S273000, C428S411100, C428S500000, C428S515000, C428S689000, C428S702000, C428S704000, C252S582000, C252S586000

Reexamination Certificate

active

06538792

ABSTRACT:

BACKGROUND OF THE INVENTION
This invention relates to electrochromic devices and more particularly electrochromic devices which are useful as light controllable windows for buildings, automobiles and passenger vehicles and various types of light controllable glasses to be used for indoor decoration or partitions; display devices; and antiglare mirrors for automobiles and other vehicles.
DESCRIPTION OF THE PRIOR ART
A conventional electrochromic device such as a light controllable glass of conventional type as disclosed in Japanese Patent Laid-Open Publication No. 63-18336 is known which glass comprises a chromogenic material in the form of a film obtained by sputtering or vacuum-depositing an inorganic oxide such as tungsten oxide (WO
3
) over a transparent electrically conductive film.
However, the conventional film formation techniques must be carried out under vacuum, resulting in increased production costs and a requirement of a large size vacuum apparatus if an electrochromic device of a large area is intended to be produced. Furthermore, since a substrate is heated at an elevated temperature during sputtering, it is necessary to select certain conditions if a substrate other than a glass, such as a synthetic resin made substrate is used, resulting in difficulties in reducing the weight of an electrochromic device.
There is also a problem that tungsten oxide can only make an electrochromic device exhibit blue color.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an electrochromic device which can be manufactured using an inexpensive color developing material with easy operations and can easily be changed in color tone.
DETAILED DESCRIPTION OF THE INVENTION
An electrochromic device proposed by the present invention solves the above-mentioned problems of the prior art by forming an ion conductive material layer containing a specified electrochromic material.
Namely, according to the present invention, there is provided an electrochromic device comprising two conductive substrates, at least one of which is transparent, and an ion conductive substance layer disposed therebetween and containing an electrochromic substance represented by the formula
wherein X
−
and Y
−
may be the same or different and are each a counter anion selected from the group consisting of a halogen anion, ClO
4
−
, BF
4
−
, PF
4
−
, CH
3
COO
−
and CH
3
(C
6
H
4
)SO
3
−
and R
1
and R
2
may be the same or different and are each a hydrocarbon group having from 1 to 20 carbon atoms.
In the present invention, two electrically conductive substrates, at least one of which is transparent, are used. The term “electrically conductive substrate” designates substrates which have a function as an electrode. Therefore, the conductive substrates used in the invention encompass those entirely formed from an electrically conductive material or formed with a non-electrically conductive substrate and an electrode layer disposed thereon. Regardless of whether a substrate is electrically conductive or not, it necessarily has a smooth surface at normal temperature but may have a flat or curved surface and may be deformable under stress.
At least of one of the two electrically conductive substrates is a transparent electrically conductive substrate and the other may be a transparent or opaque or reflective electrically conductive substrate.
Two conductive substrates both of which are transparent are suitable for a display device and a light controllable glass. A combination of a transparent conductive substrate and an opaque conductive substrate is suitable for a display device, while a combination of a transparent conductive substrate and a reflective substrate is suitable for an electrochromic mirror.
The transparent conductive substrate is generally formed by laminating a transparent electrode layer over a transparent substrate. The term “transparency” used herein designates an optical transmission ranging from 10 to 100 percent.
The opaque conductive substrate is may be a laminate obtained by laminating an electrode layer over one surface of a metal plate or a non-conductive opaque substrate such as various opaque plastics, ceramics, glasses, woods and stones.
The reflective electrically conductive substrate may be exemplified by (1) a laminate comprising a non-conductive transparent or opaque substrate and a reflective electrode layer formed thereon, (2) a laminate comprising a no-conductive transparent substrate having a transparent electrode layer on one of its surfaces and a reflective electrode layer on the other surface, (3) a laminate comprising a non-conductive transparent substrate having a reflective layer formed thereon and further a transparent electrode layer formed thereon, (4) a laminate comprising a reflective substrate and a transparent electrode layer formed thereon and (5) a plate-like substrate which itself functions as a reflective layer and an electrode.
No particular limitations is imposed on the transparent substrate which may thus be a color or colorless glass, a reinforced glass and a resin of color or colorless transparency. Specific examples of such a resin include polyethylene terephthalate, polyamide, polysulfone, polyether sulfone, polyether etherketone, polyphenylene sulfide, polycarbonate, polyimide, polymethyl methacrylate and polystyrene.
The substrates used in the present invention must have a smooth surface at normal temperature.
There is no particular restriction to the transparent electrode layer as long as it meets the requirements for achieving the purpose of the present invention. Specific examples of the electrode layer include electrically conductive film such as thin films of metals such as gold, silver, chrome, copper and tungsten or metal oxides such as ITO (In
2
O
3
—SnO
2
), tin oxide, silver oxide, zinc oxide and vanadium oxide.
The electrode has a film thickness in the range of usually 100 to 5,000 and preferably 500 to 3,000 angstrom. The surface resistance of the electrode is usually in the range of 0.5-500 and preferably 1-50 &OHgr;/sq.
No particular limitation is imposed on a method of forming the electrode layer. Any suitable conventional methods may be employed, depending upon the metal and metal oxide constituting the electrode. In general, the formation of the electrode layer is carried out by vacuum evaporation, ion plating, sputtering and a sol-gel method. The thickness of the electrode layer is selected within the range such that the transparency thereof is not affected. The electrode layer may be partially provided with an opaque electrode-activator for the purpose of imparting oxidation-reduction capability, electric conductivity and electric double layer capacitance, the electrode-activator being provided in an amount such that the transparency of the entire electrode layer is not harmed. Electrode activators eligible for the purpose of the invention are a metal such as copper, silver, gold, platinum, iron, tungsten, titanium and lithium, an organic material having oxidation-reduction capability such as polyaniline, polythiophen, polypyrrole and phthalocyanine, a carbon material such as active carbon and graphite and a metal oxide such as V
2
O
5
, MnO
2
, NiO and Ir
2
O
3
and mixtures thereof. A variety of resins may be used for integrating the electrode activator in the electrode. The opaque electrode activator may applied onto an electrode by forming on an ITO transparent electrode a composition comprising an active carbon fiber, graphite and an acrylic resin into a micro pattern in the shape of stripes or by forming on a thin-film of gold a composition comprising V
2
O
5
, acetylene black and butyl rubber in the shape of a mesh.
No particular limitation is imposed on the reflective electrode layer as long as it is stable electrochemically and has a specular surface. Eligible for the reflective electrode layer includes the films of metal such as gold, platinum, tungsten., tantalum, rhenium, osmium, iridium, silver, nickel and palladium and the film of an alloy such as platinum-p

Affiliated with

Also associated with

Rating

Electrochromic device does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Electrochromic device, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrochromic device will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3034543