Electrochromic mirror

An electrochromic mirror (10) comprises an reflective electrically conductive substrate and a transparent electrically conductive substrate, a layer of an ion conductive material (14) disposed therebetween and at least one electrochromic chromogenic layer (13) disposed either between the ion conductive material layer and the reflective electrically conductive substrate or between the ion conductive material layer and the transparent electrically conductive substrate, said electrochromic chromogenic layer containing a compound having a viologen structure represented by the formula ##STR1## wherein X.sup.- and Y.sup.- may be the same or different and each indicate a counter anion selected from the group consisting of a halogen anion, ClO.sub.4.sup.-, CH.sub.3 COO.sup.-, and CH.sub.3 (C.sub.6 H.sub.4)SO.sub.3.sup.-. The inventive mirror can be put in a various applications such as an antiglare mirror for an automobile and a decorative mirror for out door use.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to electrochromic mirrors and more particularly such 
an electrochromic mirror which can used as an antiglare mirror for an 
automobile or a decorative mirror for indoor use. 
2. Prior Art 
In Japanese Patent Laid-Open Publication No. 63-18336, there is disclosed 
an electrochromic antiglare mirror comprising a chromogenic material in 
the form of a film obtained by sputtering or vacuum-depositing an 
inorganic oxide such as tungsten oxide (WO.sub.3) over a transparent 
electrically conductive film. 
However, the production of such an electrochromic mirror becomes costly 
because of the film forming operation requiring a process carried out 
under vacuum. A demand has therefore been placed on an electrochromic 
mirror which can be manufactured with an inexpensive material and by a 
simple and easy method. 
SUMMARY OF THE INVENTION 
It is an object of the present invention made to solve the aforementioned 
problems by using a specific electrically conductive high molecular 
compound as a chromogenic film. 
According to the present invention, there is provided an electrochromic 
mirror comprising a reflective electrically conductive substrate, a 
transparent electrically conductive substrate, a layer of an 
ion-conductive material disposed therebetween and at least one 
electrochromic chromogenic layer disposed either between the 
ion-conductive material layer and the reflective electrically conductive 
substrate or between the ion-conductive material layer and the transparent 
electrically conductive substrate, the electrochromic chromogenic layer 
containing a compound having a viologen structure represented by the 
formula 
##STR2## 
wherein X.sup.- and Y.sup.- may be the same or different and each are a 
counter anion selected from the group consisting of an halogen anion, 
ClO.sub.4.sup.-, CH.sub.3 COO.sup.- and CH.sub.3 (C.sub.6 
H.sub.4)SO.sub.3.sup.-. 
One embodiment of an electrochromic mirror according to the present 
invention is characterized by all components thereof being solid.

DETAILED DESCRIPTION OF THE INVENTION 
In the present invention, an electrically conductive substrate used as a 
reflective electrically conductive substrate and a transparent 
electrically conductive substrate may be any types of substrates as long 
as they perform the function of an electrode. More specifically, the 
electrically conductive substrate may be that of which substrate itself is 
electrically conductive or that of which substrate is not electrically 
conductive but has the layer of an electrode disposed thereon. The 
electrochromic mirror according to the present invention includes a pair 
of such electrically conductive substrates one of which is the transparent 
and the other of which is reflective of light. Both these substrates may 
have a flat or curved surface and may be deformable under stress. 
The transparent electrically conductive substrate is generally a laminate 
comprising a transparent substrate and a transparent electrode layer 
formed thereon. The reflective electrically conductive substrate may be 1) 
a laminate comprising a transparent or opaque substrate and a reflective 
electrode layer formed thereon, 2) a laminate comprising a substrate 
having a transparent electrode layer on one surface and a reflective 
electrode layer on the other surface, 3) a laminate comprising a 
transparent substrate having a reflective layer formed thereon and further 
a transparent electrode layer formed thereon and 4) 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 term "transparency" used herein designates optical transmission ranging 
from 1 to 100 percent. The substrate used for the invention has a smooth 
surface at normal temperature. 
There is no particular limitation to the transparent electrode layer as 
long as it meets the requirements necessary for achieving the purpose of 
the present invention. Specific examples of the electrode layer include an 
electrically conductive membrane comprising a thin film of a metal such as 
gold, silver, chrome, copper and tungsten or a metal oxide such as ITO 
(In.sub.2 O.sub.3 --SnO.sub.2), tin oxide, silver oxide, zinc oxide and 
vanadium oxide. 
The electrode has a thickness in the range of usually 100 to 5,000, 
preferably 500 to 3,000 angstrom. The surface resistance of the electrode 
may be selected suitably depending upon the usage and applications but 
usually in the range of 0.5-500, preferably 1-50 .OMEGA./cm.sup.2. 
No particular limitation is imposed on the formation method of the 
electrode layer. Any suitable conventional methods may be selected 
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 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 include 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.sub.2 O.sub.5, WO.sub.3, MnO.sub.2, NiO and Ir.sub.2 O.sub.3 and 
mixtures thereof. These electrode activators may be integrated to the 
electrode with use of a variety of resins. 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.sub.2 O.sub.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 a film of a metal such as gold, platinum, 
tungsten, tantalum, rhenium, osmium, iridium, silver, nickel and palladium 
and a film of an alloy such as platinum-palladium, platinum-rhodium and 
stainless steel. The reflective electrode layer is necessarily disposed 
onto a substrate or a transparent substrate with the reflectiveness and 
specularity of the layer maintained. The reflective electrode layer is 
formed onto a substrate by any suitable conventional methods such as 
vacuum deposition, ion-plating and sputtering. 
There is no particular limitation to a substrate on which the reflective 
electrode layer is disposed. The substrate may be transparent or opaque. 
Specific examples of the substrate include those exemplified with respect 
to the transparent substrate described above, a variety of plastics, 
resins, glasses, woods and stones. 
No particular limitation is imposed on the above-mentioned reflective plate 
or layer as long as it has a specular surface. Silver, chrome, aluminum 
and stainless steel can be utilized. 
The plate-like substrate having a reflective layer and functioning as an 
electrode includes the substrates exemplified with respect to the 
reflective electrode among which are self-supportive. 
The ion conductive material used for the inventive electrochromic mirror is 
disposed so as to be sandwiched between the reflective electrically 
conductive substrate and the transparent electrically conductive substrate 
(these substrates are hereinafter referred to as counter-substrates). 
There is no particular limitation to a method of disposing the ion 
conductive material between the counter-substrates. The ion conductive 
material may be injected into the space provided between the substrates 
which are placed, facing each other and then sealed at the edges of the 
opposed surfaces, by vacuum injection, atmospheric injection or a meniscus 
method. Alternatively, the layer of the ion conductive material may be 
formed on the electrode layer of one of the electrically conductive 
substrates and then put together with the other electrically conductive 
substrate. Furthermore, a film-like ion conductive material is inserted 
between a pair of glasses to form a laminated glass. 
The term "ion conductive material" designates materials which can color, 
bleach and discolor an electrochromic material hereinafter described. The 
ion conductive material has preferably an ion conductivity of more than 
1.times.10.sup.-7 S/cm at room temperature. No particular limitation is 
imposed on the ion conductive material, which may thus be liquid, gel or 
solid. Solid ion conductive materials are particularly preferred for the 
purpose of the invention thereby obtaining an electrochromic mirror which 
is overall solid. 
Eligible liquid ion conductive materials are those dissolving a supporting 
electrolyte such as salts, acids and alkalis in a solvent. Any suitable 
solvents may be used as long as they can dissolve a supporting 
electrolyte. Preferred are those having polarity. Specific example of such 
solvents include water and an organic polar solvent such as methanol, 
ethanol, propylene carbonate, ethylene carbonate, dimethylsulfoxide, 
dimethoxyethane, acetonitrile, r-butyrolactone, r-valerolactone, sulforan, 
dimethylformamide, dimethoxyethane, tetrahydrofuran, propionnitrile, 
glutaronitrile, adiponitrile, methoxyacetonitrile, dimethylacetoamide, 
methylpyrrolidinone, dimethylsulfoxide, dioxolane, trimethylphosphate and 
polyethylene glycol. Preferred are propylene carbonate, ethylene 
carbonate, dimethylsulfoxide, dimethoxyethane, acetonitrile, 
r-butyrolactone, sulforan, dioxolane, dimethylformamide, tetrahydrofuran, 
adiponitrile, methoxyacetonitrile, dimethylacetoamide, 
methylpyrrolidinone, dimethylsulfoxide, trimethylphosphate and 
polyethylene glycol. These may be used singular or in combination. 
Although not restricted, salts used as a supporting electrolyte may be 
alkali metal salts, inorganic ion salts such as alkali earth metal salts, 
quaternary ammonium salts and cyclic quaternary ammonium salts. Specific 
examples of such salts include alkali metal salts of lithium, sodium or 
potassium such as LiClO.sub.4, LiSCN, LiBF.sub.4. LiAsF.sub.6, LICF.sub.3 
SO.sub.3, LIPF.sub.6, Lil, Nal, NaSCN, NaCIO.sub.4, NaBF.sub.4, 
NaAsF.sub.6, KSCN and KCl, quaternary ammonium salts or cyclic quaternary 
ammonium salts such as (CH.sub.3).sub.4 NBF.sub.4, (C.sub.2 H.sub.5).sub.4 
NBF.sub.4, (n-C.sub.4 H.sub.9).sub.4 NBF.sub.4, (C.sub.2 H.sub.5).sub.4 
NBR, (C.sub.2 H.sub.5).sub.4 NClO.sub.4 and (n-C.sub.4 H.sub.9).sub.4 
NClO.sub.4 and mixtures thereof. 
Acids used as a supporting electrolyte may be exemplified by inorganic 
acids and organic acids which include sulfuric acid, hydrochloric acid, 
phosphoric acid, sulfonic acid carboxylic acid. 
Alkalis used as a supporting electrolyte include sodium hydroxide, 
potassium hydroxide and lithium hydroxide. 
The gelatinized-liquid ion conductive material may be those which are 
gelatinized or made to be viscous by adding a polymer or a gelatinizer to 
the above-mentioned liquid ion conductive material. 
Preferred examples of such a polymer are polyacrylonitrile, 
carboxymethylcellulose, polyvinyl chloride, polyethylene oxide, 
polyurethane, polyacrylate, polyamide, polyacrylamide, cellulose, 
polyester, polypropyleneoxide and nation. 
Preferred examples of the gelatinizer are oxyethylenemethacrylate, 
oxyethyleneacrylate, urethaneacrylate, acrylamide and agar-agar. 
There is no particular limitation to the solid ion conductive material if 
it is solid at room temperature and ion conductive. Preferred examples of 
such solid ion conductive materials are polyethyleneoxide, the polymer of 
oxyethylenemethacrylate, nafion, polystyrene sulfonate, Li.sub.3 N, 
Na-.beta.-Al.sub.2 O.sub.3 and Sn(HPO.sub.4).sub.2 H.sub.2 O. Particularly 
preferred are polymer solid electrolytes derived from polymerization of a 
polyethyleneoxide-based compound, an oxyalkyleneacrylate-based compound or 
a urethaneacrylate-based compound. 
A first example of such polymer solid electrolytes is one derived form the 
solidification of a composition (hereinafter referred to as Composition A) 
containing the above-described organic polar solvent and supporting 
electrolyte and a urethaneacrylate of the formula 
##STR3## 
wherein R.sup.1 and R.sup.2 may be the same or different and each are a 
group of formula (III), (IV) or (V), R.sup.3 and R.sup.4 may be the same 
or different and each are a C.sub.1 -C.sub.20, preferably C.sub.2 
-C.sub.12 divalent hydrocarbon residue, Y is selected from a polyether 
unit, a polyester unit, a polycarbonate unit and the mixed unit thereof 
and n is an integer of 1-100, preferably 1-50, more preferably 1-20. 
Formulae (III), (IV) and (V) are represented by 
##STR4## 
wherein R.sup.5, R.sup.6 and R.sup.7 may be the same or different and each 
are a hydrogen atom or a C.sub.1 -C.sub.3 alkyl group and R.sup.8 is a 
C.sub.1 -C.sub.20, preferably C.sub.2 -C.sub.8 organic residue of divalent 
through quatervalent. 
Such organic residues may be a hydrocarbon residue such as alkyltolyl, 
alkyltetratolyl and alkylene of the formula 
##STR5## 
wherein R.sup.9 is a C.sub.1 -C.sub.3 alkyl group or hydrogen, p is an 
integer of 0-6 and if p is greater than 2 the groups of R.sup.9 may be the 
same or different. 
The hydrocarbon residue may be a group part of which hydrogen atoms are 
substituted by an oxygen-containing hydrocarbon group such as a C.sub.1 
-C.sub.6, preferably C.sub.1 -C.sub.3 alkoxy group and a C.sub.6 -C.sub.12 
aryloxy group. Specific examples of group R.sup.8 in formulae (III) 
thorough (V) are those represented by the following formulae: 
##STR6## 
Each of the divalent hydrocarbon residues represented by R.sup.3 and 
R.sup.4 in formula (II) is exemplified by a divalent chain-like 
hydrocarbon group, an aromatic hydrocarbon group and an 
alicyclic-containing hydrocarbon group. Specific examples of the 
chain-like divalent hydrocarbon group are those represented by formula 
(VI). 
Specific examples of the aromatic hydrocarbon group and 
alicyclic-containing hydrocarbon group are those represented by the 
following formulae: 
##STR7## 
wherein R.sup.10 and R.sup.11 may be the same or different and each are a 
phenylene group, a phenylene group having an alkyl subsutituent, a 
cycloalkylene group and a cycloalkylene group having an alkyl substituent, 
R.sup.12, R.sup.13, R.sup.14 and R.sup.15 may be the same or different and 
each are a hydrogen atom or a C.sub.1 -C.sub.3 alkyl group and q is an 
integer of between 1 and 5. 
Specific examples of the groups R.sup.3 and R.sup.4 in formula (II) are 
those represented by the following formulae: 
##STR8## 
In formula (II), Y indicates a polyether unit, a polyester unit, a 
polycarbonate unit and mixed unit thereof. Each of these units is 
represented by the following formulae: 
##STR9## 
wherein R.sup.16 through R.sup.21 may be the same or different and each 
are a C.sub.1 -C.sub.20, preferably C.sub.2 -C.sub.12 divalent hydrocarbon 
residue, C.sub.1 -C.sub.6 being particularly preferred for R.sup.21, m is 
an integer of 2-300, preferably 10-200, r is an integer of 1-300, 
preferably 2-200, s is an integer of 1-200, preferably 2-100, t is an 
integer of 1-200, preferably 2-100 and u is an integer of 1-300, 
preferably 10-200. 
R.sup.16 through R.sup.21 are preferably straight or branched alkylene 
groups among which methylene, ethylene, trimethylene, tetramethylene, 
pentamethylene, hexamethylene and propylene groups are preferred for 
R.sup.18, and ethylene and propylene groups are preferred for R.sup.16, 
R.sup.17 and R.sup.19 through R.sup.21. 
Each unit represented by formulae (a) through (d) may be a copolymer of the 
same or different units. In other words, if there exist a plurality of the 
groups of each R.sup.16 through R.sup.21, the groups of each R.sup.16, 
R.sup.17, R.sup.18, R.sup.19, R.sup.20 and R.sup.21 may be the same or 
different. Preferred examples of such copolymers include a copolymer of 
ethylene oxide and a copolymer of propylene oxide. 
The urethaneacrylate of formula (II) has a molecular weight in the range of 
2,500-30,000, preferably 3,000-20,000. 
The urethaneacrylate has preferably 2-6, more preferably 2-4 functional 
groups per molecule. 
The urethaneacrylate may be prepared by any suitable conventional methods. 
The organic polar solvent is added in an amount of 100-200, preferably 
200-900 weight parts per 100 parts of the urethaneacrylate. Too less 
amount of adding the organic polar solvent results in insufficient ion 
conductivity, while too much amount causes a reduction in mechanical 
strength. 
No particular limitation is imposed on the supporting electrolyte as long 
as it is not obstructive in achievement of the purpose of the invention. 
Preferred are those already exemplified above. The supporting electrolyte 
should be added in an amount of 0.1-30, preferably 1-20 weight percent of 
the organic polar solvent. 
Composition (A) is essentially obtained by solidifying the 
urethaneacrylate, the organic nonaqueous solvent and the supporting 
electrolyte. If necessary, Composition (A) may be added with any suitable 
components as long as they are not obstructive to the achievement of the 
purpose of the invention. Such components may be crosslinkers and 
polymerization initiators. 
The solid polymeric electrolyte of the first example may be inserted 
between the electrically conductive substrates disposed, facing each other 
by injecting Composition (A) into a selected space between the substrates 
in a conventional manner and curing the same. The term "curing" used 
herein designates a state where polymerizing or crosslinking component is 
cured with the progress of polymerization (polycondensation) or 
crosslinking and thus the composition does not flow at room temperature. 
The composition thus cured has the basic structure in the form of network. 
A second example of the polymeric solid electrolyte is obtained by 
solidifying Composition (B) comprising an organic polar solvent, a 
supporting electrolyte, a poly-functional acryloyle-modified polyalkylene 
oxide and a mono-poly-functional acryloyle-modified polyalkylene oxide 
represented by the formula 
##STR10## 
wherein R.sup.22, R.sup.23, R.sup.24 and R.sup.25 may be the same or 
different and each are hydrogen and an alkyl group having 1-5 carbon atoms 
and n is an integer of greater than 1. 
Specific examples of such alkyl group include methyl, ethyl, i-propyl, 
n-propyl, n-butyl, t-butyl and n-pentyl. Preferred for R.sup.22, R.sup.23 
and R.sup.24 are hydrogen and a methyl group. Preferred for R.sup.25 are 
hydrogen, a methyl and ethyl group. 
n in formula (XVII) is an integer of greater than 1, usually between 1 and 
100, preferably 2 and 50, more preferably 2 and 30. 
Specific examples of compounds represented by formula (XVII) are those 
having 1-100, preferably 2-50, more preferably 1-20 oxyalkylene units, 
such as methoxypolyethylene glycol methacrylate, methoxypolypropylene 
glycol methacrylate, ethoxypolyethylene glycol methacrylate, 
ethoxypolypropylene glycol methacrylate, methoxypolyethylene glycol 
acrylate, methoxypolypropylene glycol acrylate, ethoxypolyethylene glycol 
acrylate, ethoxypolypropylene glycol acrylate and mixtures thereof. 
If n is greater than 2, the compound may be those having different 
oxyalkylene units, that is, copolymerized oxyalkylene units which for 
instance have 1-50, preferably 1-20 oxyethylene units and 1-50, preferably 
1-20 oxypropylene units. Specific examples of such compounds are 
(ethylene. propylene) glycol methacrylate, ethoxypoly (ethylene.propylene) 
glycol methacrylate, methoxypoly (ethylene.propylene) glycol methacrylate, 
methoxypoly (ethylene.propylene) glycol acrylate, ethoxypoly methoxypoly 
(ethylene.propylene) glycol acrylate and mixtures thereof. 
The polyfunctional acryloyl-modified polyalkylene oxide may be a 
bifunctional acryloyl-modified polyalkylene oxide represented by the 
formula 
##STR11## 
wherein R.sup.26, R.sup.27, R.sup.28 and R.sup.29 each are hydrogen and a 
C.sub.1 -C.sub.5 alkyl group and m is an integer of greater than 1; 
or a polyfunctional acryloyl-modified polyalkylene oxide having more than 
three functional groups represented by the formula 
##STR12## 
wherein R.sup.30, R.sup.31 and R.sup.32 each are hydrogen and a C.sub.1 
-C.sub.5 alkyl group, p is an integer of greater than 1, q is an integer 
of 2-4 and L is a connecting group of valence indicated by q. 
Preferred alkyl groups for R.sup.26, R.sup.27, R.sup.28 and R.sup.29 are 
methyl, ethyl, i-propyl, n-propyl, n-butyl, t-butyl, t-butyl and n-pentyl 
among which hydrogen and methyl are particularly preferred. 
m in formula (XVIII) is an integer of greater than 1, usually 1-100, 
preferably 2-50, more preferably 2-30. Preferred examples of compounds of 
formula (XVIII) are those having 1-100, preferably 2-50, more preferably 
1-20 oxyalkylene units such as polyethylene glycol diacrylate, 
polypropylene glycol dimethacrylate, polyethylene glycol diacrylate, 
polypropylene glycol dimethacrylate and mixtures thereof. 
If m is greater than 2, the compounds of formula (XVIII) may be those 
having different oxyalkylene units, that is, polymerized oxyalkylene unit 
having 1-50, preferably 1-20 oxyethylene units and 1-50, preferably 1-20 
oxypropylene units, such as poly(ethylene.propylene)glycol dimethacrylate, 
poly(ethylene.propylene)glycol diacrylate and mixtures thereof. 
Preferred alkyl groups for R.sup.30, R.sup.31 and R.sup.32 are methyl, 
ethyl, i-propyl, n-propyl, n-butyl, t-butyl and n-pentyl. Particularly 
preferred are hydrogen and a methyl group. 
p is an integer of greater than 1, usually between 1 and 100, preferably 2 
and 50, more preferably 2 and 30. 
q is a number of connecting group "L" and an integer of between 2 and 4. 
Connecting group "L" is a divalent, trivalent or quatravalent hydrocarbon 
group having 1-30, preferably 1-20 carbon atoms. 
Such divalent hydrocarbon groups may be alkylene, arylene, arylalkylene, 
alkylarylene and hydrocarbon groups having those groups as the base 
skeleton. Specific examples of such hydrocarbon groups are those 
represented by the following formulae: 
EQU --CH.sub.2 -- 
EQU --CH.sub.2 CH.sub.2 -- 
and 
##STR13## 
(Bz represent a benzene ring). 
Such trivalent hydrocarbons groups may be alkyltryl, aryltryl, 
arylalkyltryl, alkylaryltryl and hydrocarbon groups having those groups as 
the base skelton. Specific examples of such hydrocarbon groups are those 
represented by the following formulae: 
##STR14## 
(Bz represents a benzene ring). 
Specific examples of compounds of formula (XIX) are those having 1-100, 
preferably 2-50, more preferably 1-20 of an oxyalkylene units such as 
trimethylolpropanetri(polyethylene glycol acrylate), 
trimethylolpropanetri (polyethylene glycol methaacrylate), 
trimethylolpropanetri (polypropylene glycol acrylate), 
trimethylolpropanetri (polypropylene glycol methaacrylate), 
tetramethylolmethanetetra(polyethylene glycol acrylate), 
tetramethylolmethanetetra (polyethylene glycol methaacrylate) 
tetramethylolmethanetetra(polypropylene glycol acrylate), 
tetramethylolmethanetetra(polypropylene glycol methaacrylate), 
2,2-bis[4-(acryloxypolyethoxy)phenyl]propane, 
2,2-bis[4-(methaacryloxypolyethoxy)phenyl]propane, 
2,2-bis[4- (acryloxypolyisopropoxy)phenyl]propane, 
2,2-bis[4- (methaacryloxypolyisopropoxy)phenyl]propane and mixtures 
thereof. 
If p is more than 2, compounds of formula (XIX) may be those having 
different oxyalkylene units, that is, polymerized oxyalkylene units having 
1-50, preferably 1-20 of oxyethylene units and 1-50, preferably 1-20 
oxypropylene units. Specific examples of such compounds include 
trimethylolpropanetri(poly(ethylene.propylene)glycol acrylate), 
trimethylolpropanetri(poly(ethylene.propylene)glycol methaacrylate), 
tetramethylmethanetetra(poly(ethylene.propylene)glycol acrylate), 
tetramethylolmethanetetra(poly(ethylene.propylene)glycol acrylate) and 
mixtures thereof. 
Needless to mention, there may be used the difunctional acryloyl-modified 
polyalkyleneoxide of formula (XVIII) and the polyfunctional 
acrylo-modified polyalkyleneoxide of formula (XIX) in combination. When 
these compounds are used in combination, the weight ratio of the compound 
of formula (XVIII) to that of formula (XIX) is in the range between 
0.01/99.9 and 99.9/0.01, preferably 1/99 and 99/1, more preferably 20/80 
and 80/20. The weight ratio of the compound of formula (XVII) to the 
polyfunctional acryloyl-modified polyalkyleneoxide is in the range of 
usually between 1/0.001 and 1/1, preferably 1/0.05 and 1/0.5. 
The above-described organic polar solvent should be added in an amount of 
50-800, preferably 100-500 weight percent based on the total weight of the 
compound of formula (XVII) and the polyfunctional acryloyl-modified 
polyalkyleneoxide. 
The above-described supporting electrolyte should be added in an amount of 
1-30, preferably 3-20 weight percent based on the total weight of the 
compound of formula (XVII), the polyfunctional acryloyl-modified 
polyalkyleneoxide and the organic polar solvent. 
If necessary, Composition (B) may be added with another components 
optionally as long as they do not give adverse effect on the inventive 
electrochromic mirror. Although not restricted, such components may be 
photopolymerization initiators or thermal polymerization initiators. These 
initiators should be added in an amount of 0.05-5, preferably 0.01-3 
weight percent based on the total weight of the compound of formula (XVII) 
and the polyfunctional acryloyl-modified polyalkylene oxide. 
The polymeric solid electrolyte described above as a second example may be 
inserted between electrically conductive substrates facing each other by 
injecting Composition (B) into a selected site therebetween by any 
suitable method. The "curing" used herein designates a state where a 
polymerizable or crosslinkable component such as monofunctional or 
polyfunctional acryloyl-modified polyalkyleneoxide is cured with the 
progress of polymerization or crosslinking and hence the composition 
entirely stays unfluidized. In this case, the monofunctional or 
polyfunctional acryloyl-modified polyalkyleneoxide has the basic structure 
in the form of networks. 
Needless to mention, ion conductive materials other than the above 
exemplified are also eligible. 
Description will now be made in detail of a compound used as the 
electrochromic chromogenic layer of the electrochromic mirror according to 
the invention which compound has a viologen structure represented by the 
formula 
##STR15## 
wherein X.sup.- and Y.sup.- indicate counter anions and may be the same 
or different and selected from the group consisting of a halogen anion, 
ClO.sub.4.sup.-, CH.sub.3 COO.sup.- and CH.sub.3 (C.sub.6 
H.sub.4)SO.sub.3.sup.-. The halogen anion may be F.sup.-, Cl.sup.-, 
Br.sup.- and I.sup.-. 
No limitation is imposed on the viologen structure-containing compound as 
long as it possesses electrochromic properties. Such compounds are 
exemplified by high molecular compounds having the viologen structural 
unit or units containing the viologen structure as repeating units, a high 
molecular weight substituent at the terminal end of the viologen structure 
or molecular chains part of which is substituted with a group having the 
viologen structure; and low molecular compounds having the viologen 
structure. The compound having the viologen structure-repeating units may 
be that having the viologen structure in the side chain or in the main 
chain. There is no limitation to repeating units in the main chain of such 
a compound having the viologen structure in the side chain. Such repeating 
units may be hydrocarbon units, oxygen-containing units, 
nitrogen-containing units, polysiloxane units and copolymerized units 
thereof. 
The compound having the viologen structure may be a polymer or copolymer 
represented by the formula 
##STR16## 
wherein m is an integer of more than 1, preferably between 1 and 1,000, n 
is an integer of more than 0, preferably between 0 and 1,000, R.sup.33 is 
a C.sub.1 -C.sub.20, preferably C.sub.1 -C.sub.12 divalent hydrocarbon 
residue or merely indicates the bond of the viologen group directly to a 
polymer chain not through the hydrocarbon residue, namely covalently bond, 
R.sup.34, R.sup.35 and R.sup.36 each are a C.sub.1 -C.sub.20, preferably 
C.sub.1 -C.sub.12 hydrocarbon group and a hetero atom-containing 
substituent and a halogen atom and X.sup.- and Y.sup.- indicate counter 
anions with respect to viologen and may be same or different. 
The divalent hydrocarbon may be a hydrocarbon group and an 
oxygen-containing hydrocarbon group. Specific examples of the hydrocarbon 
group include an aliphatic hydrocarbon group such as methylene, ethylene, 
propylene, tetramethylene, pentamethylene and hexamethylene and an 
aromatic hydrocarbon such as phenylene, biphenylene and benzylidene. 
Specific examples of the oxygen-containing hydrocarbon group include an 
aliphatic alkoxylene group such as --OCH.sub.2 --, --OCH.sub.2 CH.sub.2 -- 
and --OCH.sub.2 CH.sub.2 CH.sub.2 --, an aliphatic dialkoxylene group such 
as --OCH.sub.2 CH.sub.2 O-- and --OCH.sub.2 CH.sub.2 CH.sub.2 O--, an 
aromatic aryloxy group such as --O(C.sub.6 H.sub.4)-- and --OCH.sub.2 
(C.sub.6 H.sub.4)-- and an aromatic diaryloxy group such as --O(C.sub.6 
H.sub.4)O and --OCH.sub.2 (C.sub.6 H.sub.4)O--. 
Specific examples of X.sup.- and Y .sup.- include a halogen anion such as 
F.sup.-, Br.sup.- and I.sup.-, ClO.sub.4.sup.-, CH.sub.3 COO.sup.- and 
CH.sub.3 (C.sub.6 H.sub.4)SO.sub.3.sup.-. 
Preferred hydrocarbon groups for R.sup.34, R.sup.35 and R.sup.36 are an 
alkyl group such as methyl, ethyl, propyl and hexyl and an aryl group such 
as phenyl, tryl, benzyl and naphtyl. Preferred hetero atom-containing 
substituents are a C.sub.1 -C.sub.20, preferably C.sub.1 -C.sub.12 
oxygen-containing hydrocarbon group, amide, amino and cyano groups. Such 
oxygen-containing hydrocarbon groups include an alkoxyl group such as 
methoxy and ethoxy an aryloxy group such as phenoxy and triloxy, a 
carboxyl group and a residual carboxylic acid ester. 
In the case where the compound of formula (XX) is a copolymer, it may have 
the repeating units the mode of which polymerization is block-, random- or 
alternate. 
The compound having the viologen structure may also be a polymer or 
copolymer represented by the formula 
##STR17## 
wherein m, n and X.sup.- and Y.sup.- are the same as defined in formula 
(XX), n being preferably 0, R.sup.37 and R.sup.39 may be the same or 
different and each are the same as those as defined with respect to 
R.sup.33 in formula (XX) and R.sup.38 and R.sup.40 may the same or 
different and each are the same as those as defined with respect to 
R.sup.34 in formula (XX). 
In the case of the compound of formula (XXI) is a copolymer, it may have 
the repeating units the mode of which polymerization is block, random or 
alternate. 
Moreover, the compound having the viologen structure may also be a polymer 
or copolymer represented by the formula 
##STR18## 
wherein m, n and X.sup.- and Y.sup.- are the same as defined in formula 
(XX), n being preferably 0, R.sup.41 is the same as those as defined with 
respect to R.sup.33 in formula (XX) and R.sup.42, R.sup.43 and R.sup.44 
may be the same or different and each are the same as those as defined 
with respect to R.sup.34 in formula (XX). 
In the case of the compound of formula (XXII) is a copolymer, it may have 
the repeating units the mode of which polymerization is block, random or 
alternate. 
Furthermore, the compound having the viologen structure may be a copolymer 
represented by the formula 
##STR19## 
wherein p is an integer of more than 0, preferably between 0 and 20, q is 
an integer of 0-1,000 and R.sup.45 is the same as those as defined with 
respect to R.sup.33 in formula (XX). 
Further alternatively, the compound having the viologen structure may also 
be a polymer or copolymer of the formula 
##STR20## 
wherein r is an integer of more than 1, preferably between 1 and 1,000, 
R.sup.46 is the same as those as defined with respect to R.sup.33 in 
formula (XX) and R.sup.47 is the same as those as defined with respect to 
R.sup.33 in formula (XX). 
The typical examples of the compound having viologen structure used for the 
present invention has been exemplified by the compounds of formulae (XX) 
through (XIV). The specific examples of compounds which are included 
within the range of these formulae and which are not but eligible for the 
invention are give below. 
##STR21## 
The electrochromic chromogenic layer used for the present invention 
essentially contains the compound having a viologen structure represented 
by formula (I), but is usually formed from this compound only. The 
electrochromic chromogenic layer can be obtained by forming the membrane 
or film of the compound onto the above-described electrically conductive 
substrate. Although no particular limitation is imposed on the method for 
the formation of such a membrane or film, the membrane or film may be 
formed by drying the solution which has been obtained by dissolving the 
chromogenic compound in a solvent and coated onto the electrically 
conductive substrate or by cooling the chromogenic compound which has been 
melted on heating and casted over the substrate, the former being 
particularly preferred. 
The solvent used for the former method may be any types of solvents as long 
as they can dissolve the chromogenic compound and evaporate after being 
coated. Specific examples of the solvent include dimethylsulfoxide, 
dimethylacetamide, dimethylformamide, N-methylpyrrolidone, 
.gamma.-valerolactone, dimethoxyethane, acetnitrile, propionnitrile, 
tetrahydrofuran, dioxane, methanol, ethanol, propanol, chloroform, 
toluene, benzene, nitrobenzene and dioxolane. 
There may be employed any suitable coating method such as cast coating, 
spin coating, dip coating, spray coating, blade coating and flow coating. 
The electrochromic chromogenic layer thus formed is easily colored and 
bleached by oxidation-reduction reaction caused by applying an electrical 
voltage. 
The electrochromic chromogenic layer has a thickness in the range of 
0.01-50 .mu.m, preferably 0.1-20 50 .mu.m. 
If necessary, the compound having the viologen structure of formula (I) may 
be added with a compound which can facilitating coloration. 
As described above, the electrochromic mirror according to the invention 
comprises a reflective electrically conductive substrate, a transparent 
electrically conductive substrate, an ion conductive layer disposed 
therebetween and at least one electrochromic chromogenic layer disposed 
either between the reflective electrically conductive substrate and the 
ion conductive layer or between the transparent electrically conductive 
substrate and the ion conductive layer, the electrochromic chromogenic 
layer containing a compound having a viologen structure represented by 
formula (I). The basic arrangement of these components of the inventive 
mirror will be described below. 
FIG. 1 through 4 show the typical arrangements of the components of the 
inventive electrochromic mirror. 
The electrochromic mirror (10) shown in FIG. 1 comprises a first laminate 
comprising a transparent electrically conductive substrate including a 
transparent substrate (11) and the layer of a transparent electrode (12) 
formed on one surface of the substrate and an electrochromic chromogenic 
layer (13) formed on the electrode layer (12); a second laminate 
comprising a reflective electrically conductive substrate including a 
transparent or opaque substrate (17) and a reflective electrode layer (16) 
formed thereon; and an ion conductive layer disposed in sandwich relation 
in the space properly provided between the first and second laminates 
which are placed so that the electrochromic chromogenic layer (13) and the 
reflective substrate (16) face each other. 
The another example of the electrochromic mirror (10) shown in FIG. 2 
comprises a first laminate comprising a transparent electrically 
conductive substrate including a transparent substrate (11) and a layer of 
a transparent electrode (12) formed on one surface of the substrate and an 
electrochromic chromogenic layer (13) formed on the electrode layer (12); 
a second laminate comprising a transparent substrate (11) having a 
transparent electrode layer (12) formed on one surface of the substrate 
and a reflective layer (18) formed on the other surface; and an ion 
conductive material (14) disposed in sandwich relation in the space 
properly provided between the first and second laminates which are placed 
so that the electrochromic chromogenic layer (13) and the transparent 
electrode layer of the second laminate (16) face each other. 
The electrochromic mirror shown in FIG. 3 comprises a first laminate 
comprising a transparent electrically conductive substrate including a 
transparent substrate (11) and a transparent electrode layer (12) formed 
on one surface of the substrate; a second laminate comprising a 
transparent or opaque substrate (17) having a reflective electrode layer 
(16) formed thereon and an electrochromic chromogenic layer (13) formed on 
the reflective electrode layer (16); and an ion conductive material (14) 
disposed in sandwich relation in the space properly provided between the 
first and second laminates which are placed so that the transparent 
electrode layer and the electrochromic chromogenic layer (13) face each 
other. 
FIG. 4 shows another example of the inventive electrochromic mirror (10) 
comprises a first laminate including a transparent substrate (11) having a 
transparent electrode layer (12); a second laminate including a 
transparent substrate (11) having a transparent electrode layer (12) and 
an electrochromic chromogenic layer (13) formed one after another on one 
surface and a reflective layer formed on the other surface; and an ion 
conductive material (14) disposed in sandwich relation in the space 
properly provided between the first and second laminates which are placed 
so that the transparent electrode layer of the first laminate and the 
electrochromic chromogenic layer (13) of the second laminate face each 
other. 
Needless to mention, each of the electrochromic mirrors shown in FIG. 1 
thorough 4 can be colored or bleached by electrochromic phenomenon brought 
by an electric voltage applied over each electrode. An electric voltage 
can be applied by any conventional methods. 
There is no particular limitation to a method for forming each of the 
layers or films of the inventive electric mirror. Each of the layers or 
films can be formed in accordance with the methods described above. Taking 
an example from the electrochromic mirror shown in FIG. 1, the transparent 
electrode layer (12) is formed on the transparent substrate (11) by the 
above-described method and then the electrochromic chromogenic layer (13) 
is formed on the electrode layer (12) thus formed therby obtaining a 
laminate (referred to as laminate A). Another laminate (referred to as 
laminate B) is obtained by forming a reflective electrode layer (16) on a 
substrate (17) in accordance with the procedure described above. Laminates 
A and B are placed, facing each other and spaced 1-1,000 .mu.m apart and 
sealed at their edges with a sealant (15), leaving a portion used for an 
inlet, thereby forming a empty cell. An ion conductive material or the 
precursor thereof is injected from the inlet into the cell in a manner 
described above so as to form the layer of the ion conductive material 
thereby producing an electrochromic mirror. 
When laminates A and B are placed, facing each other, a spacer may be 
inserted therebetween so as to provide the space retained constantly. No 
particular limitation is imposed on such a spacer. There may be used one 
in the form of beads and a sheet. The spacer may be inserted between the 
electrically conducted substrates facing each other or provided by forming 
the protrusions of an insulate material of the electrode on an electric 
conductive substrate. 
The ion conductive material layer may be formed by injecting the precursor 
thereof the space between the electrically conductive substrates facing 
each other and curing the same. No particular limitation is imposed on a 
method for curing the precursor. Therefore, the precursor may be cured by 
lightning, on heating or by injecting a reactive liquid which cures with 
the progress of time before the precursor being injected. The inlet of the 
cell may be sealed suitably after completion of the injection of the 
precursor of the ion conductive material. 
Alternatively, a transparent electrode layer (17), an electrochromic 
chromogenic layer (13) and an ion conductive layer (14) are formed one 
after another in the order of mentioned in the above-described manner 
thereby forming a laminate (referred to as laminate A'). Another laminate 
(referred to as laminate B') is obtained by forming a reflective 
electrically conductive layer (16) on a substrate (17). Laminates A' and 
B' are placed, facing each other so that the ion conductive material layer 
of laminate A' contacts the reflective electrically conductive of laminate 
B' and then sealed at their edges with a sealant (15). 
The electrochromic mirror shown in FIG. 2 may be obtained by forming a 
transparent electrode layer (12) on one surface of a transparent substrate 
(11) and a reflective layer on the other surface and then following the 
same procedure as described for the electrochromic mirror shown in FIG. 1. 
The electrochromic mirrors shown in FIGS. 3 and 4 can be produced by 
following the same procedure as described for those shown in FIGS. 1 and 
2. 
Although FIGS. 1 through 4 illustrate the typical examples of the structure 
of the inventive electrochromic mirror, it is not limited to these 
structures and thus may contain additional components. Such additional 
components may be an ultraviolet blocking layer such as an ultraviolet 
reflective layer and an ultraviolet absorbing layer and an overcoat layer 
provided to protect the mirror entirely or the surface of each of the 
films or layers. The ultraviolet blocking layer is preferably disposed on 
the outer side of a transparent substrate (11) or on a transparent 
electrode layer formed on the transparent substrate. The overcoat layer is 
preferably disposed on the outer side of a transparent substrate (11) or 
the outer side of a reflective layer (18). 
The electrochromic mirror according to the invention is quick in response 
and possesses sufficient durability and is excellent memory function due 
to the electrochromic chromogenic layer containing a specific compound. 
Furthermore, the use of such an electrochromic chromogenic layer leads to 
the production of the inventive electrochromic mirror with ease and at low 
cost. The inventive mirror is advantageous because the density of 
coloration thereof can be adjusted easily by changing the specifications 
of the compound contained in the electrochromic chromogenic layer. 
Furthermore, in the present invention, it is possible to produce a mirror 
having a large size and improved in safety due to the capability of using 
a solid electrolyte as an ion conductive material layer which is free from 
scattering. 
With the forgoing advantage in view, the inventive electrochromic 
chromogenic mirror is useful for an antiglare mirror for an automobile or 
decorative mirror for illumination. 
The present invention will now be explained in further detail with 
reference to Examples, which are given only by way of illustration an are 
not intended for limiting the invention. 
EXAMPLE 1 
(1) Synthesis of Electrochromic Compound 
A 100 ml three-necked flask was charged with 5 grams (12.9 mmol) of 
N-methyl-p-styrylbipyridyl, 0.92 gram (13 mmol) of acrylamide and 30 ml 
pure water. The mixture was stirred with a magnetic stirrer and heated to 
50.degree. C. after being added with 0.1 ml of an aqueous solution 
containing 30% hydrogen peroxide. After 12 hours the reaction solution was 
added to acetone in order to precipitate a polymer. The polymer thus 
obtained had an average molecular weight of 3,500 and a structure 
represented by the formula given below in which m and n each are about 
7.5. 
##STR22## 
(2) Preparation of Electrochromic Mirror 
The compound produced in (1) was dissolved in dimethylformamide to make the 
10% solution, by weight, of the compound. The solution was applied onto 
the ITO(indium tin oxide)-coated surface of a glass substrate. The glass 
substrate was heated on a hot plate to remove nitrobenzene and then had 
the thin film (thickness of 5 .mu.m) of the copolymer formed thereon, 
thereby obtaining a transparent electrically conductive substrate with an 
electrochromic layer (designated as Laminate A). 
A substrate having a platinum film formed thereon was used as a high 
reflective electrode (designated as Laminate B). On the edges of the 
platinum-film side of the Laminate B except for a portion forming an inlet 
for injecting the solution of an electrolyte precursor, an epoxy-based 
adhesive was applied in the form of a line. Laminate A was superimposed on 
Laminate B such that the electrochromic layer and the platinum electrode 
layer face each other and then pressurized so as to cure the adhesive, 
thereby obtaining an empty cell with an inlet. 
Separately from these procedure, 0.4 gram of lithium perchlorate was added 
to the mixed solution of 1.0 gram of methoxypolyethylene glycol 
monomethacrylate (oxyethylene unit thereof is 4 in number) manufactured by 
Shin Nakamura Chemical Industry Co., Ltd under the name of ME04, 0.02 gram 
of polyethylene glycol dimethacrylate (oxyethylene unit thereof is 9 in 
number) manufactured by Shin Nakamura Chemical Industry Co., Ltd under the 
name of 9G and 4.0 grams of .gamma.-butylolactone. The resulting mixture 
was added with 0.02 gram of 
1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on (manufactured by Melk 
Co,. Ltd, under the name of "Diecure-1116") as a photopolymerization 
initiator in a dark room and then injected into the above-obtained cell 
through the inlet after being deaerated. 
After the inlet was sealed with an epoxy-based sealant, the electrolyte 
precursor in the cell was cured by being exposed to fluorescent through 
the trasnparent substrate to form a solid electrolyte, thereby obtaining a 
all solid type electrochromic mirror. 
The mirror when assembled was not colored and had a reflectance of 85%. 
Upon application of an electric voltage, the mirror was quick in response 
and excellent in electrochromic properties. The mirror was colored upon 
application of voltage of 1.5 V and was 10% in reflectance with respect to 
633 nm wavlength light. After 100 hours, the mirror still was colored and 
10% in reflectance. 
EXAMPLE 2 
(1) Synthesis of Electrochromic Compound 
4-(4'-bipyridine)pyridiniumbromide was reacted with 1,2-dibromoethane in 
dimetylformamide at a temperature of 100.degree. C. thereby obtaining 
1-propyl-1'-bromoethyl-4,4'-bipyridiumbromide. This reaction mixture was 
subjected to elimination of HBr with use of an NAOH solution, thereby 
obtaining 1-propyl-1'-vinyl-4,4'-bipyridiumbromide. 
The monomer thus obtained was subjected to bulk polymerization using 
di-t-butylperoxide as a catalyst at a temperature of 130.degree. C. 
thereby obtaining a polymer having an average molecular weight of about 
4,000 and a structure represented by the following formula wherein an is 
about 10. 
##STR23## 
(2) Preparation of Electrochromic Mirror 
The compound produced in procedure (1) was dissolved in nitrobenzene to 
make the 10% solution, by weight, of the compound. The solution thus 
obtained was applied onto the platinum-film-formed side (reflective 
electrode side) of Laminate B as used in Example 1 and then heated on a 
hot plate to remove nitrobenzene thereby obtaining a reflective 
electrically conductive substrate (designated as Laminate C) with the 
layer of the electrochromic thin film of the compound having a thickness 
of 5 .mu.m. 
A glass substrate with an electrically conductive layer of palladium was 
used as a transparent electrically conductive substrate (designated as 
Laminate D). An epoxy-based resin was applied in the form of lines on the 
edges other than a portion forming an inlet of an electrolyte precursor 
solution, of Laminate D. Laminate C was superposed on Laminate D such that 
the electrochromic layer faced the transparent electrode layer while being 
pressed to cure the adhesive thereby to provide an empty cell with an 
inlet. 
Separately from these procedures, 0.4 gram of lithium perchlorate was added 
to the mixed solution of 1.0 gram of methoxypolyethylene glycol 
monomethacrylate (oxyethylene unit thereof is 4 in number) manufactured by 
Shin Nakamura Chemical Industry Co., Ltd under the name of ME04, 0.02 gram 
of polyethylene glycol dimethacrylate (oxyethylene unit thereof is 9 in 
number) manufactured by Shin Nakamura Chemical Industry Co., Ltd under the 
name of 9G and 4.0 grams of .gamma.-butylolactone thereby obtaining a 
homogeneous solution. The solution thus obtained was added with 0.02 gram 
of 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on (manufactured by 
Melk Co,. Ltd, under the name of "Diecure-1116" as a photopolymerization 
initiator in a dark room and then injected into the above-obtained cell 
through the inlet after being deaerated. 
After the inlet port of the cell was sealed with an epoxy-based adhesive, 
the precursor of the electrolyte was cured by being exposed to a 
fluorescent through the transparent substrate to form a solid electrolyte 
layer, thereby obtaining an all solid type electrochromic mirror as shown 
in FIG. 3. 
Upon completion of assembling the mirror, it is not colored and 85% in 
reflectance. Upon application of electric voltage, the mirror was quick in 
response and excelled in electrochromic properties. More specifically, 
when an electric voltage of 1.5 V was applied to the mirror, it is colored 
and 15% in reflectance. Even after the application of such electric 
voltage was terminated, the mirror was still kept colored and 10% in 
reflectance 100 hours later.