BACKGROUND OF THE APPLICATION The present invention is directed to the Electro- optical device like liquid crystal or electrochromic cells and the variable transparent articles having the device along with appropriate battery components and control circuit elements.

Optically switchable solids, liquids, and gases are known in the art that exhibit reversible spectral coloration in the visible region by electrochromism, thermochromism, piezochromism or photochromism. A review of the subject relating to films is given in the article entitled"Optically Switchable Thin Films: A Review"by Charles B. Greenberg, Thin Solid Films, 251 (1994) pp. 81-93, Elsevier Science S. A, which is hereby incorporated by reference. Employing these materials in optically switchable products for limiting the transmittance of light is a challenging endeavor. Optically switchable eyewear employing photochromatic materials for glass and plastic substrates are available in the marketplace.

Also, mirrors employing electrochromic materials are available in the marketplace. Also, numerous recent patents indicate activity in the area of electrochromic materials for automotive and architectural windows and mirrors and eyewear.

An example of the variable transparency electro-optical devices for eyewear employing both electro-optical material to form a cell which also has a photochromic material as an additional element to the glasses or as one of the cell transparent plates is disclosed in U. S. Patent No. 5,608,567 (Grupp).

Additionally, electrochromic devices employing various composites like monolithic multilayer electrochromic

composites with interbuffer layers are disclosed in PCT publication WO 96/37809 and electrochromic eyewear with suitable electrochromic cells and power supply and circuitry are discussed in U. S. Patent Nos. 5,455,637 and 5,455,638.

Also, the art has disclosed liquid crystal displays having chiral nematic liquid crystal displays for a homeotropic alignment and negative dielectric anisotropy as indicated in U. S. Patent No. 5,477,358. All of the aforementioned documents and patents are hereby incorporated in toto by reference.

The industry strives to develop and extend these technologies into useful products, for instance eyewear, and windows for apertures and partitions in automobiles, housing, and/or buildings. For instance with photochromic substrates as eyewear these products require UV radiation or actinic radiation to initiate and develop the optical switching.

Therefore, in surroundings where this type of radiation is at a minimum, the switchability is impaired. For instance photochromic eyewear worn within motor vehicles such as automobiles do not receive sufficient UV radiation for switchability. While electrochromic eyewear is operable within automobiles, it requires a portable power source.

Also, photochromic switchability is not controllably variable in switchability to permit stopping the switching at various desired points.

It is an object of the present invention to provide an electro-optic device for a variable transparent article providing the ability to vary the percentage of transparency in the article where convenient given the power and circuitry requirements but which can also have optical switchability when such power and circuitry components are not available or when another power source is available.

SUMMARY OF THE INVENTION One aspect of the present invention is the electro optical device which constitutes an electro optical cell

having a chromogenic component in addition to the electro- optically switchable feature. The chromogenic component can be a photochromic, thermochromic, and/or dichroic material and mixtures of these. The chromogenic component as a coating, film or layer can be on one or more of the transparent substrates of the electro-optical cell with an electrochromic feature as the electro-switchable feature. Also the chromogenic component as a coating, film, or layer can be on one or more of the transparent substrates of the electro-optic device that is a liquid crystal cell with one or more dichroic dyes present with the liquid crystal material. In another aspect of the invention, the chromogenic component can be a chromogenic guest material with or within the electro-optic device such as a liquid crystal host material as the electro- switchable (including magneto-switchable) feature interstitially located between two or more electrodes in the electro optical device. The liquid crystal host undergoes molecular reorientation under the influence of an applied electric and/or magnetic field in the electro-optical device.

The reorientation is such that the chromogenic guest material provides enhanced optical switching or flexibility to the overall switching effect. One way that this may occur is from the forced orientation of the chromogenic guest molecule to incoming light, or by structural or coordination changes imposed by the reoriented host molecules. The chromogenic component as a photochromic or thermochromic coating, film or layer on the substrate of the electro-optical cell or device would also enhance optical switching or flexibility of the overall switching effect. The host and guest chromogenic approach can be accomplished with the use of polymeric or hybrid hard coat materials for at least glass or plastic substrates with transparency features by thin film deposition techniques. Application processes such as this do not require any separate glue-like adhesive material for coating the substrate, which may have additional functional coatings or layers. For instance, the guest material could be a dichroic

material such as cobalt (II) complex or a photochromic or thermochromic material. The electric or magnetic field can be provided in the electro optical device from electroconductive layers, films and/or coatings to effect a change in the guest material that is contained within the liquid crystal host material along with the change effected in the host material.

One or more of the liquid crystal materials of one or more smectic liquid crystal layers, one or more nematic liquid crystal layers, and/or one or more lyotropic liquid crystal layers or combinations and mixtures of these as the host material could already have been oriented. The photochromic and/or thermochromic material in the switchable material of the electro-optic cell would switch to a darker state upon exposure of the electro-optic cell to UV or actinic light sources or to heat.

The electro optical device with the chromogenic material is suitable for use with automotive transparencies such as privacy glass, shade bands, and passenger partition screens in vehicles; architectural window use such as skylights and other windows; and eyewear. For the electro optical device, the variable transparent or transmission articles for these uses are adaptable to receive the appropriate power from a power supply and control circuitry.

For eyewear the power supply could be from batteries in one or more frame members of the eyewear and the control circuitry could be located elsewhere, for instance in a motor vehicle.

Additionally, the power supply from or on the vehicle itself can be utilized where the control circuitry would be located in or within or from the vehicle. For example the control circuitry and/or power could be routed to the eyeglasses through a connection in the frame of the glasses from the seatbelt of the vehicle. This way the electro-optical feature of the eyewear could be used while in the vehicle where a photochromic response is limited. The eyewear could be disconnected from the power supply and control circuitry and

used outside the vehicle through the photochromic or thermochromic material.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side elevational view of the eyewear having the exploded section of the variable transparent lenses removed from the frame and the frame is sectioned to show conducting wires and a port or a battery in the stem.

Fig. 23 is a top view of the cross-section of the transparency lens of Fig. 1 along line A-A'which line is normal to the major surface of the transparency of Figures 2.

Fig. 3 is an alternative top view of Fig 2.

DETAILED DESCRIPTION OF THE INVENTION In the description and claims of this application the recitation of numerical ranges includes the word"about" at both the lower and the upper ends of the range unless expressly indicated to the contrary. Also specific references to patents and publications for specific disclosures and teachings incorporates those disclosures and teachings by reference into this patent application.

In Fig. 1 eyewear frame 11 can be any typical construction of eyewear frame having the lens holder section 13 engaged by a hinge or the like to side members 15 and 17.

Side member 15 is hingedly engaged through hinge 19 while side member 17 is hingedly engaged through hinge 21, respectively, to the lens holder section 13. For instance the side members hinged engagement can be via a leaf spring that biases the former into one of two orientations relative to the lens holder section. The cutaway section of side member 15 shows electrical connection 23 which is connected to port 25 and to the lens holder section to deliver electric current from the port 25 to the lenses 27 and 29. Side member 17 shows a cutaway view of electrical connection 31 which is electrically connected to the battery 33 inside member 17. When battery 33 is present in the eyewear of Figure 1, port 25 can be a

connection for electrical circuitry to control the electric power supply (current and/or voltage) to lenses 27 and 29. In this case an electrical connection between port 25 through electrical connection 23 at or around lenses 27 and 29 would also be present but is not shown in Figure 1. In the case where battery 33 is not present in the eyewear then port 25 is used for both the power supply and also the electrical control circuitry to provide for the appropriate power delivery and switching electronics to the lenses 27 and 29.

In Figure 1, lens 27 is shown with a cutaway section of a coating 35 on the exterior major surface of the transparency. Such a coating could also be present on lens 29 and the coating would be a photochromic coating having a photochromic material. A non-exclusive example would be a photochromic polyurethane coating composition that when exposed to activating light, radiation exhibits photochromic performance properties. That is the photochromic compound exhibits a reversible change in color when exposed to light radiation involving ultraviolet rays, such as the ultraviolet radiation in sunlight or in the light of a mercury of halogen type lamp. other polymeric materials can be utilized in the coating such as acrylics, polyesters, polyamides and the like.

The photochromic materials that are useful for the coating are those that are well known in the art and have been synthesized and suggested for use in applications in which a sunlight-induced reversible color change or darkening is desired. The most widely described classes of photochromic compounds are oxazines, pyrans and fulgides, any of which can be used. The general mechanism responsible for the reversible change in color, i. e., a change in the absorption spectrum in the visible range of light (400 to about 770 nanometers) exhibited by different types of photochromic compounds has been described and categorized in the article entitled "Chromogenic Materials (Photochromic)"in Kirk-Othemer Encyclopedia of Chemical Technology Fourth Edition, 1993, pp 321-332, by John C. Crano. Other classes of photochromic

compounds include indolino spirophrans and indolino spirooxazines. These types of materials upon activation by UV radiation transform from a colorless closed ring compound into a colored open ring species. For the fulgides photochromic compound an electro cyclic mechanism can involve the transformation of a colorless open ring form to a colored closed ring form. These types of compounds can be used in the coating applied to lens 27 or 29 of Figure 1 by any application technique known to those skilled in the art including thin film deposition techniques.

Other photochromic compounds that may be utilized with the coating composition of the present invention are the organic photochromic compounds generally having at least one activated absorption maxima within the range of between 400 to about 770 nanometers which can be incorporated, as in dissolved or dispersed in the coating composition. Any of the aforementioned photochromic compounds including such examples as spiro (indoline) naphthoxazines and like as described in U. S. Patent Nos. 3,562,172 ; 3,578,602; 4,215,010 and 5,405,958. Also spiro (indoline) pyridobenzoxazines and spiro (benindoline) naphthoxazines as described in U. S. Patent No.

4,931,219 can be used.. Other photochromic compounds as discussed in the following U. S. patents can also be used: 4,816,584; 4,880,667 ; 4,818,096 and the article entitled "Spiro (Indoline) Pyrans Techniques in Chemistry", Vol. III, "Photochromism"Chapter 3 by Glen H. Brown, editor, John Wiley and Sons, New York, 1971 can be used.

Other organic photochromic substances that can be used are those having at least one absorption maximum and preferably two absorption maxima, within the visible range of between 400 and less than 525 nanometers. Many of such chromines are described in the following U. S. Patents: 3, 567, 605 ; 4,826,977; 5,066,818 ; 5,238,931; 5,272,132; 5,384,077 ; 5,466,398 ; 5,552,090; 5,565,146; 5,573,712 and 5,578,252.

Another group of photochromic substances contemplated for use in the coating of the present invention can be those having an absorption maximum within the visible range of between 400 and 500 nanometers and another absorption maximum within the visible range of between 500 and 700 nanometers. An example of these substances includes certain benzopyran compounds having substituents at the two positions of the pyran ring including a dibenzo-fused five member heterocyclic compound and a substitute or unsubstituted heterocyclic ring such as a benzothieno or benzofurano ring fused to the benzene portion of the benzopyran. Such materials are disclosed in U. S. Patent Nos. 5,429,774 ; 5,514,817 ; 5,552,091 and WO 96/14596, Other photochromic compounds and substances that can be used in the coating include mercury dithizonates as in U. S. Patent No. 3,361,706.

The fulgides and fulgimides as described in U. S. Patent No.

4,931,220 at column 20, line 5, through column 21, line 38.

In addition to or in lieu of the photochromic material, thermochromic materials can be used. These materials can be those which exhibit changes in physical properties such as absorptance, reflectance and refractive index as the result of thermodynamic state changes such as between the semiconductor and metal state. These types of thermochromic materials include certain vanadium oxides and titanium oxides, which have relatively low absorptance in the semiconductor state and high absorptance and high reflectance in the metal state. The thermodynamic transitions between the semiconductor and metal states are reversible and take place fairly rapidly so that thin films of such materials are useful. For the invention other suitable thermochromic materials are those containing a known thermochromic dye, such as thermochromic liquid crystal, a three-component system consisting of an electron-donating color-developing organic compound, a color developer therefore and a compound inducing the color developing reaction between the two, or a thermochromic material containing the above-mentioned

components in resinous solid solution, as disclosed in the U. S. Patent Nos. 4,028, 118, and 4,732,810. The above- mentioned materials show at the normal temperature range, only one of the states before and after said color variation, while the other state being present only during the application of heat or cold while the state of the normal temperature range being restored when the application of such heat or cold-is terminated.

Photochromic compounds in coatings such as polyurethane coatings have been disclosed in patent document German Democratic Republic Patent No. 116,520 and in European Patent Application No. 0 146 136 and U. S. Patent No. 4,889,413 and Japanese Patent Application No. 3-269507 and 5-28753.

Suitable other polyurethanes that can be used in the coating are those produced by the reaction of an organic polyol component with an isocyanate or a polyisocyanate component that can provide a polyurethane component having a Fischer microhardness in the range of about 50 to 150 neutons per mm2.

Such polyurethane reactants and reactions are well known to those skilled in the art. For instance, methods for the preparations of polyurethanes are described in Ullmann's Encyclopedia of Industrial Chemistry, Fifth Edition, 1992, Vol. A21, pp 665-716. The polyurethane is one having soft block and hard block segments to produce the Fischer microhardness number within the aforementioned range. The relative amounts of the ingredients are typically expressed as a ratio of the available number of reactive isocyanate groups to the available number of reactive hydroxyl groups, i. e., an equivalent ratio of NCO: OH. A suitable example of a ratio is NCO: OH of 1.0: 1.0 but can range from 0.3: 1.0 to 3.0: 1.0.

Since free isocyanate groups at not stable since they react with water or compounds that contain reactive hydrogen atoms, it is preferred that the NCO groups are blocked with certain selected organic compounds that render the isocyanate group inert to react with hydrogen compounds at room temperature.

Suitable blocking compounds include volatile alcohols,

epsilon-caprolactam or ketoxime compounds and the like known to those skilled in the art. The isocyanate compounds can be aliphatic, aromatic or aralkyl isocyanates. The organic polyol useful in producing the polyurethane can be polyacrylic polyols, polyester polyols and/or polyether polyols or polyoxyalkylene polyols or organic polyols such as aliphatic diols, triols and polyhydric alcohols. Also suitable are apoxy polyols, polyhydric polyvinyl alcohols, urethane polyols, and mixtures of any of these polyols. Additionally, amide-containing polyols can be used.

The amount of the photochromic or thermochromic substance present in the composition alone or in ratio with a mixture of photochromic compounds is such that the coating composition to which the photochromic compound or compounds is applied or in which they are incorporated exhibits a desired resultant color. For example, a substantially neutral color such as shades of gray or brown when activated with unfiltered sunlight, i. e., as near a neutral color as possible given the colors of the activated photochromic compounds and exhibits the desired intensity as measured by the change in optical density (delta OD) of a delta OD of 0.4 or more when tested at 95°F after 15 minutes of activation using the standard photochromic response testing method. Generally the amount of the photochromic or thermochromic substance incorporated into the coating composition can range from 0.1 to 40 wt% based on the weight of the coating composition.

In addition, other additives such as compatible tints or dyes and adjuvant materials can be incorporated into the coating composition. Some of the latter materials can include rheology control agents, leveling agents, surfactants, initiators, cure inhibiting agents, free radical scavengers and adhesion promoting agents. Other adjuvants include UV absorbers and stabilizers such as hindered amine light stabilizers, asymmetric diaryloxalamide and the like stabilizers disclosed in U. S. Patent Nos. 4,720,356 and 5,391,327,.

The transparent substrate such as lenses 27 and 29 can be made from glass or transparent like plastic such as polymerization product of CR-39 monomer available from PPG Industries, Inc. Generally the transparency such as the transparent lenses 27 and 29 can be made of any ophthalmic glass and or plastic such as thermoset and thermoplastic organic polymeric materials like thermoplastic polycarbonate type polymers and copolymers and homopolymers or copolymers of polyol (allyl carbonate). In some embodiments the electro- optical cell can have one substrate which has in spaced apart facing, preferably matching, arrangement an encapsulating material rather than a second substrate. The encapsulating material can be that similar to the substrate or more flexible material than that of the substrate which merely encloses or envelops the substrate and switching material rather than provide support like a substrate.

Examples of organic polymeric materials that may be substrates for the coating composition of the present invention are polymers prepared from individual monomers or mixtures of monomers selected from the following groups: (a) diacrylate or dimethacrylate compounds represented by graphic formula I : I wherein Ri and R2 may be the same or different and are hydrogen or methyl, A is methylene (CH2) and n is an integer of from 1 to 20; (b) diacrylate or dimethacrylate compounds represented by graphic formula II:

wherein D is CH2CR1R2 and p is an integer of from 1 to 50; and (c) an acrylate or a methacrylate compound having an epoxy group represented by graphic formula III: III wherein R3is hydrogen or methyl.

In graphic formulae I, II and III, like letters used with respect to the definitions of different substituents have the same meaning.

Examples of diacrylate or dimethacrylate compounds represented by graphic formulae I and II include diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, etc., butanediol dimethacrylate and poly (oxyalkylene dimethacrylates), e. g., polyethylene glycol (600) dimethacrylate. Examples of acrylate or methacrylate compounds represented by graphic formula III include glycidyl acrylate and glycidyl methacrylate.

Further examples of organic polymeric materials which may be coated with the photochromic/thermochromic coating compositions described herein include: polymers, i. e., homopolymers and copolymers, of the monomers and mixtures of monomers represented by graphic formulae I, II and III,

bis (allyl carbonate) monomers, diisopropenyl benzene monomers, ethoxylated bisphenol A dimethacrylate monomers, ethylene glycol bismethacrylate monomers, poly (ethylene glycol) bis methacrylate monomers, ethoxylated phenol bis methacrylate monomers, alkoxylated polyhydric alcohol polyacrylate monomers, such as ethoxylated trimethylol propane triacrylate monomers, urethane acrylate monomers, such as those described in U. S. Patent 5,373,033, and vinylbenzene monomers, such as those described in U. S. Patent 5,475,074 and styrene; polymers, i. e., homopolymers and copolymers, of polyfunctional, e. g., mono-, di-or multi-functional, acrylate and/or methacrylate monomers, poly (Cl-Cl2 alkyl methacrylates), such as poly (methyl methacrylate), poly (alkoxylated phenol methacrylates), cellulose acetate, cellulose triacetate, cellulose acetate propionate, cellulose acetate butyrate, poly (vinyl acetate), poly (vinyl alcohol), poly (vinyl chloride), poly (vinylidene chloride), polyurethanes, thermoplastic polycarbonates, polyesters, poly (ethylene terephthalate), polystyrene, poly (alpha methylstyrene), copoly (styrene-methyl methacrylate), copoly (styrene-acrylonitrile), polyvinylbutyral and polymers, i. e., homopolymers and copolymers, of diallylidene pentaerythritol, particularly copolymers with polyol (allyl carbonate) monomers, e. g., diethylene glycol bis (allyl carbonate), and acrylate monomers, e. g., ethyl acrylate, butyl acrylate.

Transparent copolymers and blends of transparent polymers are also suitable as substrates. Preferably, the host material is an optically clear polymerized organic material prepared from a thermoplastic polycarbonate resin, such as the carbonate-linked resin derived from bisphenol A and phosgene, which is sold under the trademark, LEXAN; a polyester, such as the material sold under the trademark, MYLAR; a poly (methyl methacrylate), such as the material sold under the trademark, PLEXIGLAS; polymerizates of a polyol (allyl carbonate) monomer, especially diethylene glycol

bis (allyl carbonate), which monomer is sold under the trademark CR-39, and polymerizates of copolymers of a polyol (allyl carbonate), e. g., diethylene glycol bis (allyl carbonate), with other copolymerizable monomeric materials, such as copolymers with vinyl acetate, e. g., copolymers of from 80-90 percent diethylene glycol bis (allyl carbonate) and 10-20 percent vinyl acetate, particularly 80-85 percent of the bis (allyl carbonate) and 15-20 percent vinyl acetate, and copolymers with a polyurethane having terminal diacrylate functionality, as described in U. S. patents 4,360,653 and 4,994,208; and copolymers with aliphatic urethanes, the terminal portion of which contain allyl or acrylyl functional groups, as described in U. S. Patent 5,200,483; poly (vinyl acetate), polyvinylbutyral, polyurethane, polymers of members of the group consisting of diethylene glycol dimethacrylate monomers, diisopropenyl benzene monomers, ethoxylated bisphenol A dimethacrylate monomers, ethylene glycol bismethacrylate monomers, poly (ethylene glycol) bismethacrylate monomers, ethoxylated phenol bismethacrylate monomers and ethoxylated trimethylol propane triacrylate monomers; cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, thermoplastic polycarbonates, polystyrene and copolymers of styrene with methyl methacrylate, vinyl acetate and acrylonitrile.

Suitable coatings like photochromic polyurethane coating composition can be combined with organic polymeric materials such as optically clear polymerizates, i. e., materials suitable for optical applications, such as optical elements, e. g., plano and vision correcting ophthalmic lenses, windows, clear polymeric films, automotive transparencies, e. g., windshields, aircraft transparencies, plastic sheeting, etc. Such optically clear polymerizates may have a refractive index that may range from about 1.48 to about 1.75, e. g., from about 1.495 to about 1.66. Specifically contemplated are optical elements made of thermoplastic polycarbonates.

Application of the photochromic polyurethane coating

composition of the present invention to a polymeric film in the form of an"applique"may be accomplished using the methods describe in column 17, line 28, to column 18, line 57, of U. S. Patent 5,198,267.

The transparent substrate lenses 27 and 29 fit into the glass frame as lenses generally fit into glass frames as into apertures 37 and 39. In fitting into the glass frame the lenses can make connection with the electrical connection 23 and/or 31. This connection is to provide the electric or magnetic field for the electro-optical feature of lenses 27 and 29 as more fully described in Figure 2.

In Figure 2 the electro-optical device 29, which can be the transparent or variable transparent lens has the conductive substrates 37 and 39 each with two major surfaces.

The substrates 37 and 39 are in matched arrangement as shown in Figure 2 to form a space 41. For instance, space 41 can be in the range of distance of from 0.01 to 50 mm, more suitably from 0.01 to 15 mm. Space 41 contains a polymer-electrolyte or variable electro-optically switchable material 43 for the electrochromic electro-optical cell useful with the photochromic and/or thermochromic material described above.

For Substrate 37, which can be any of the aforementioned substrates, the major surface facing the other conductive substrate 39 can have at least an electrochromic layer 45.

Various known electrochromic materials for layer 45 include those such as the oxides of molybdenum (MoO3), tungsten (W03), vanadium (V205), niobium (Nb2Os), titanium (TiO2), chromium (Cr203), praseodymium (PRO2), and ruthenium (Ru02), tungsten oxide, and compounds of tungsten, where tungsten oxide is preferred. In addition, ternary metal oxides and tungsten bronzes, such as Mo1yWyO3, HXW03, HXMo03, KXW03 and NaxWO3, wherein x and y are less than 1 may be used. The major surface of conductive substrate 39 which faces conductive substrate 37 has a counter electrode layer 47 such as any of those known to those skilled in the art such as for example iridium oxide or Prussian blue. Space 41 which contains a

switchable material or polymer electrolyte 43 can be sealed between the two conductive substrates 37 and 39 by lamination or by seals or sealant 49 A&Bo Also the electrochromic cell has bus bars 51 and 53 to provide electrical current to the electrochromic and counter electrode layers, respectively.

When preparing an electrochromic device, the substrate is preferably first coated with an electroconductive film as part of layer 47 over which is deposited the electrochromic film. The electroconductive and the electrochromic films can be present on or over a substantial portion of the surfaces of the substrate and encapsulating material. Such a substantial portion is that portion of the substrate and encapsulating material that allows for the electro-optical variable transmission feature to be useful as a product. For instance the portions of the substrate and encapsulating material that are in a frame need not have such films, and such non-coated portions can be masked to avoid coating or have the film deleted. Preferably the films are present on the entire major surface of the substrates and/or encapsulating material in matched facing arrangement in the electro-optical cell of the present invention. The electroconductive film may be any of those known in the art that are used as electroconductive films in electrochromic devices. Such films can be transparent thin films of metal or metal oxide, e. g., fluorine-doped tin oxide or tin-doped indium oxide, commonly referred to as ITO (indium/tin oxide), preferably ITO comprising for instance a weight ratio of about 90: 10 indium to tin. Other materials such as antimony-doped tin oxide and aluminum-doped zinc oxide may also be used as the electroconductive film. A suitable sheet resistance for such a film can be in the range of 10 to 30 ohms per square.

A suitable thickness for the electroconductive film can be in the range of about 1300 to about 4000, e. g., 2000 to 4000, Angstroms. The electroconductive film may be deposited by a variety of methods known in the art so long as the substrate is not deleteriously affected by such method. High

temperature pyrolytic methods may be used to deposit electroconductive films on glass, but such methods generally are not suitable for lower melting polymeric substrates. A suitable method for depositing the electroconductive film, such as ITO, on polymeric substrates is direct current (DC) sputtering, for instance, DC magnetron reactive sputtering (MSVD), such as the MetaMode@ sputtering system, which is a high deposition rate, low temperature process that is described in U. S. Patent Nos. 4,851,095 and 5,225,057, and WO patent document 96/06203 (European Patent document 776383).

Vacuum web coating with a chilled drum is another method of coating ITO on plastic substrates. Using such techniques, ITO films having a visible transmittance of greater than 80% and a sheet resistance of 18-20 ohms/square may be prepared at about 20°C.

Additionally an adhesion improving polymeric primer can be disposed at the interface of the substrate and the electroconductive film: to improve the adhesion of the electroconductive film to the surface of the plastic substrate for improved environmental durability and long-term cycling (coloring/bleaching cycles) to aid in preventing crazing and/or cracking of the substrate and the electroconductive film. An acrylate copolymer primer of acrylic acid and a substituted acrylate, such as cyanoethylacrylate, hydroxyethylacrylate, methylmethacrylate and mixtures of such substituted acrylates can be used. The application and curing of the primer can be as disclosed in U. S. Patent 5,618,390.

The primed and electroconductive film coated transparent substrates are paired to prepare a transparent electrochromic device. Preferably the electrochromic film is deposited on the electroconductive film of one plastic substrate and a complementary electrochromic or counter electrode film is deposited on the electroconductive film of the other substrate. Tungsten oxide may be deposited on a substrate by thermal evaporation of tungsten oxide, but is preferably deposited by direct current (DC) magnetron

sputtering of tungsten in a rare gas/oxygen atmosphere at high total gas pressures (exceeding 20 milliTorr). Also the opposite facing substrate in addition to a primed layer has a counter electrode or an electrochromic layer coat over the electroconductive film. This additional film may be one of nitrogen-containing iridium oxide as disclosed in U. S. Patent 5,618,390.

In one embodiment, the configuration of the electrochromic cell 29 has three electrodes; namely a working electrode (WE), a reference electrode (RE), and a counter- electrode (CE). The working electrode can be the nitrogen- containing iridium oxide film ; the reference electrode can be a standard calomel electrode (SCE); and the counter-electrode can be platinum foil having an area of 25 square centimeters.

Using potentiostatic conditions with an applied voltage in the range of from-0.5 to-0.1 volts versus a standard calomel electrode, the amount of charge inserted and removed is about 13-40 mC/cm2. Also the electrochemical reduction can be conducted under galvanostatic conditions including an applied current of about 1.5X10-' amperes and a voltage limit set at 1.5 volts. The amount of charge inserted and removed under these conditions is about 23 millicoulombs per square centimeter (mC/cm2). A coulometer wired in series to the WE can be used to measure the charge. The accumulated charge may be in the range of about 1 to 40, preferably 15 to 29, more preferably 20 to 29, millicoulombs per square centimeter.

After the two substrates have been primed, if necessary, and coated with electroconductive and electrochromic or counter electrode film, the pair of substrates are assembled to form a cell with the electrochromic films in a face-to-face relationship. The cell 29 may be produced by disposing a preformed sheet of an ion- conducting polymer between the two half cells and laminating the resultant assembly in an autoclave. The layer of ion- conducting material, preferably an ion-conducting polymer, bonds with both coated surfaces to form a laminated article.

Also useful in the cell is an ion-conducting polymer electrolyte which is a proton-conducting polymer.

Homopolymers of 2-acrylamido-2-methylpropanesulfonic acid (AMPS@ from Lubrizol) and copolymers of AMPS material with various monomers may be utilized in the form of preformed sheets which can be laminated between the substrates, or in the form of a liquid reaction mixtures of monomers which are cast and cured in place. A suitable proton-conducting polymer electrolyte in accordance with the present invention is a copolymer of AMPS material and N, N-dimethylacrylamide (DMA), preferably cast and cured in place. A suitable example of copolymers of AMPS and DMA is prepared from AMPS and DMA monomers in a molar ratio range of about 1: 3 to 1: 2. The thickness of the polymer electrolyte can be in the range of about 0.001 to about 0.025 inch (0.0254 to 0.625 millimeter "mm"), more suitably 0.005 to 0.015 inch (0.127 to 0.381 mm.), or as described in U. S. Patent 5,327,281. The AMPS/DMA copolymer proton-conductive electrolyte is preferably cast in place as a solution of monomers in 1-methyl-2-pyrrolidinone (NMP) and water. The monomer solution comprises a photoinitiator to polymerize the monomers upon exposure to actinic radiation, preferably ultraviolet (UV) light.

Preferred UV initiators include benzoin, methyl ether, and diethoxyacetophenone. The monomer solution may be poured between two separate electroconductive and electrochromic coated substrates assembled together with a 0.005 to 0.025 inch (0.381 to 0.508 mm.) TEFLON@ spacer 49 A and 49B held in place with a commercially available sealant, e. g. Torr Seal@ from Varian Vacuum Products. Curved lenses are typically about 70 mm. in diameter and 1 to 2 mm. thick. For a pair of curved lens substrates, the monomer solution may be poured onto the concave surface of one lens substrate and the convex surface of the other lens substrate placed in contact with the monomer solution, thus forming the monomer solution into a thin film between the lens substrates. Exposure to UV light sufficient to cure the polymer electrolyte is typically about

30 minutes for a mercury lamp and about one to 3 minutes for a xenon lamp. In addition to the above-described ion-conducting polymer electrolytes, other materials, as for example materials comprising hydrogen uranylphosphate or polyethylene oxide/LiCl04, may also be employed. Also, inorganic films such as LiNbO3, LiBO3, LiTa03, LiF, Ta205, Na2AlF6, Sb205'nH2O+Sb203, Na20 multiplication dot 11 A1203, MgF2, Zr02, Nb205 and A1203 are contemplated for use as the electrolyte material. The resultant electrochromic lens is generally crack-free with insignificant haze (0.3 to 0.4%). The electrical connections to the electrochromic device are preferably made with electrically conductive bus bars. The optical transmittance of the lens at 550 nanometers"nm."can be typically about 75 percent or higher in the bleached state and has a minimum of about 10 percent in the darkened state in the voltage range of from about +1.5 to-1.5 volts for a charge in the range of about 23 to 29 millicoulombs per square centimeter (mC/cm2).

The charge capacity of such films may range from less than 3 to more than 30 millicoulombs per square centimeter. For electrochromic articles other than eyewear, the transmittance in the bleached state may be lower and in the darkened state may be higher or lower.

The bus bars 51 and 53 can be powered by the power source 33 which is the battery of the glasses frame or from the power source in or on the motor vehicle along with the proper adjustment of the voltage and amperage of the power source. The power source from the car can be the car battery with proper adjustment of the current and voltage and/or one or more solar power cells located on the automobile for instance in the windshield. The electric power is controlled by electronic circuit 55 for electrochromic or as later described liquid crystal operation. Circuit 55 can functionally control through its connection at port 25 as shown in Figure 1 along with electrical connection 31 and 23.

The power source and electronic circuitry for controlling the electrochromic cell can both be present in the side members 15

or 17 of the eyewear of Figure 1. Such an electrochromic cell can be produced by suspension lamination method as described in allowed U. S. Patent Application Serial No. 08/970,031 filed November 13,1997, for"Suspension Lamination Method and Device"and also the subject of published PCT patent application, Publication No. WO 97/43089.

The electrochromic cell shown as the solid state version in Figure 2 is a laminate of two substrates sandwiching a polymer-electrolyte in space 41. Figure 3 shows another solid state version of the electrochromic cell with complementary thin films utilizing a thin film stack on one substrate. In either Figure 2 or 3 one or the other electrode can be pre-charged, for cycling, with the insertion-extraction ion J+ of equation 1: MnOm. y H20 + Xe + Xi <==> JxMn°m H2O Equation 1 where the right side of the equation indicates the darkened state while the left side indicates the clear state. This equation is for the inorganic oxide films exhibiting cathodic coloration by the reversible double insertion of electrons and monovalent charge-compensating ions. In equation 1, M is a multivalent cation of the film with valence 2m divided by n.

Both m and n are integers nominally. The ion being inserted while forming the color center is J+. Typically X is greater than zero and less than 0.5 and as X approaches 0.5, the film changes reversibly from a clear transmitting state in normal lighting to increasingly darker shade of the same hue. In Figure 3 the conductive substrate 39 can have a tungsten oxide coating 45 which is electrically connected to a bus bar 53.

The tungsten oxide film is in contact with the electrolyte film 57. In contact with film 57 is the counter electrode film 47 and in electrical contact with the counter electrode film is an indium tin oxide coating 59. The coating 59 is a thin film coating which can be deposited by any thin film technique known to those skilled in the art as are the other coatings in the electrochromic cell. The coating 59 has bus bar 51 to carry the electrical power to the electrode film.

A suitable example of the power and control components are those for micro-electronics useful with lightweight, battery-powered electrochromic (EC) eyewear.

Such components can include a primary, lithium-type cell and a secondary, sealed lead acid-type cell in a hybrid, power- sharing configuration capable of supplying the low-energy, high-current (pulse) drain requirements of microelectronics, e. g. a switchable electrochromic ("EC") lens. A switch-mode power supply controller manages the power-sharing load on the hybrid battery system such that the secondary cell is charged by the primary cell. The system is capable of meeting short- term pulse drain requirements of switching EC lenses from clear to fully darkened at an acceptably fast rate and with a long-term operating life requirements of approximately 1500 cycles. A suitable lead acid-type battery can be elongate, of uniform, right-rectangular cross section and provide over 20 mA-hours capacity. A suitable lithium-type battery also can be elongate, of uniform, right-rectangular cross section and provides over 180 mA-hours'capacity, all in a tiny volume compatible with one or more volume-restricted spaces, like side members 15 and 17. The lithium-type and lead acid-type batteries can be of approximately equal form factor and volume, for symmetric placement thereof in a void within either side member. Dual like-cell battery configurations can be used in conjunction with a flexible circuit defining one or more frame-mounted transmissivity switches. The controller electronics can be a microcontroller that fits within a tiny void formed in the lens holder at the bridge. Finally an external, battery-powered battery charger case and circuit can also be used with EC eyewear powered by dual batteries. Such power supplies and controllers are those as described in U. S.

Patent 5,455,637 and 5,455,638.

The electro-optic cells of Figures 2 and 3 as described above for electrochromic cells with the photochromic coating can be modified as another form of electro optic device. Such a modified form is an electro-optic device with

a liquid crystal cell wherein the liquid crystal material has a photochromic, thermochromic and/or dichroic material. In this aspect of the invention a cell similar to one of those of Figures 2 and 3 has a liquid crystal material, compound or polymer with the dispersed photochromic, thermochromic and/or dichroic material. The latter can be formed by dispersing a smectic, nematic and/or lyotropic liquid crystal or the like in a polymer matrix or using liquid crystal polymers. These liquid crystal containing materials would be the switchable material 43 in space 41 rather than the polymer electrolyte discussed above. In addition to the liquid crystal material, the material 43 of space 41 could have one or more dichroic dyes, and/or thermochromic materials in a guest-host relationship with the liquid crystal. Alternatively the material 43 could have one or more photochromic material. This is facilitated by the orderly change in the orientation of the liquid crystal molecules changing between a homeotropic orientation state or a homogeneous orientation state and a random orientation state by heat, electric field and/or magnetic field. For the electro-optic device of Figures 2 and 3 a tungsten oxide or counter electrode coating, film, or layer would not be needed. The substrate or substrates would be conductive by composition and/or by the presence of one or more conductive coatings, layers, or films on the substrate.

Also the counter electrode coating or layer of Figures 2 and 3 for liquid crystal could be at least one polyimide coating, layer, or film to orient the liquid crystal or one or more other like orienting coatings.

Suitable examples of the photochromic and thermochromic materials are those as described above for the electrochromic cell. Suitable examples of dichroic materials are dichroic dyes useful alone or in a mixture with each other or in a mixture with photochromic and/or thermochromic materials as chromogenic materials. These materials have the ability to absorb light of a particular polarization when they are molecularly aligned within a liquid crystal material.

When used in a film or other material which predominantly scatters only one polarization of light, the dichroic dye causes the material to absorb one polarization of light more than another. Suitable dichroic dyes include Congo Red (sodium diphenyl-bis-alpha-naphthylamine sulfonate), methylene blue, stilbene dye Color Index (CI) =620), and 1,1'- diethyl-2,2'-canine chloride (CI=374 (orange) or CI=518 (blue)). The properties of these dyes, and methods of making them, are described in E. H. Land, Colloid Chemistry (1946).

These dyes have noticeable dichroism in polyvinyl alcohol and a lesser dichroism in cellulose. Other suitable dyes include those listed with their properties and the methods of making them, discussed in the Kirk Othmer Encyclopedia of Chemical Technology, Vol. 8, pp. 652-661 (4th Ed. 1993), and in the references cited therein.

The one or more chromogenic components with or without the dichroic dye may be used in the liquid crystal material in an amount of usually from 0.05 to 15% by weight, preferably from 0.5 to 5% by weight, based on the amount of a liquid-crystal material.

Other useful guest compounds include aromatic compounds, such as mono-substituted benzene derivative, di- substituted benzene derivative, tri-substituted benzene derivative, tetra-substituted benzene derivative, mono- substituted biphenyl derivative, di-substituted biphenyl derivative, tri-substituted biphenyl derivative, tetra- substituted biphenyl derivative, mono-substituted naphthalene derivative, di-substituted naphthalene derivative, tri- substituted naphthalene derivative, tetra-substituted naphthalene derivative, mono-substituted pyridine derivative, di-substituted pyridine derivative, tri-substituted pyridine derivative, tetra-substituted pyridine derivative, mono- substituted pyrazine derivative, di-substituted pyrazine derivative, tri-substituted pyrazine derivative, tetra- substituted pyrazine derivative, mono-substituted pyrimidine derivative, di-substituted pyrimidine derivative, tri-

substituted pyrimidine derivative, tetra-substituted pyrimidine derivative, mono-substituted azulene derivative, di-substituted azulene derivative, tri-substituted azulene derivative, tetra-substituted azulene derivative, mono- substituted pyrrole derivative, di-substituted pyrrole derivative, tri-substituted pyrrole derivative, tetra- substituted pyrrole derivative, mono-substituted thiophene derivative, di-substituted thiophene derivative, tri- substituted thiophene derivative, tetra-substituted thiophene derivative, mono-substituted furan derivative, di-substituted furan derivative, tri-substituted furan derivative, tetra- substituted furan derivative, mono-substituted pyrylium salt derivative, di-substituted pyrylium salt derivative, tri- substituted pyrylium salt derivative, tetra-substituted pyrylium salt derivative, mono-substituted quinoline derivative, di-substituted quinoline derivative, tri- substituted quinoneline derivative, tetra-substituted quinoline derivative, mono-substituted pyridazine derivative, di-substituted pyridazine derivative, tri-substituted pyridazine derivative, tetra-substituted pyridazine derivative, mono-substituted triazine derivative, di- substituted triazine derivative, tri-substituted triazine derivative, mono-substituted tetrazine derivative, di- substituted tetrazine derivative, mono-substituted anthracene derivative, di-substituted anthracene derivative, tri- substituted anthracene derivative, or tetra-substituted anthracene derivative. Examples of the electron donative group attached to the guest compound as described above may include: amino group, alkyl group (methyl, ethyl, isopropyl, n-propyl, n-butyl, t-butyl, sec-butyl, n-octyl, t-octyl, n- hexyl, cyclohexyl, etc.), alkoxy group (methoxy, ethoxy, propoxy, butoxy, etc.), alkylamino group (N-methylamino, N- ethylamino, N-propylamino, N-butylamino, etc.), hydroxyalkylamino group (N-hydroxymethylamino, N- (2- hydroxyethyl) amino, N- (2-hydroxypropyl) amino, N- (3- hydroxypropyl) amino, N- (4-hydroxybutyl) amino, etc.),

dialkylamino group (N, N-dimethylamino, N, N-diethylamino, N, N- dipropylamino, N, N-dibutylamino, N-methyl-N-ethylamino, N- methyl-N-propylamino, etc.), hydroxyalkyl-alkylamino group (N- hydroxymethyl-N-methylamino, N-hydroxymethyl-N-ethylamino, N- hydroxymethyl-N-ethylamino, N- (2-hydroxyethyl)-N-methylamino, N- (2-hydroxyethyl)-N-ethylamino, N- (3-hydroxypropyl)-N- methylamino, N- (2-hydroxypropyl)-N-ethylamino, N- (4- hydroxybutyl)-N-butylamino, etc.), dihydroxyalkylamino group (N, N-dihydroxymethylamino, N, N-di- (2-hydroxyethyl) amino, N, N-di- (2-hydroxypropyl) amino, N, N-di- (3-hydroxypropyl) amino, N-hydroxymethyl-N- (2-hydroxyethyl) amino, etc.), mercapto group and hydroxy group. On the other hand, examples of the electron attractive group may include: nitro group, cyano group, halogen atom (fluorine, chlorine, bromine), trifluoromethyl group, carboxyl group, carboxy ester group, carbonyl group and sulfonyl group. Specific examples of the guest compound which may be used may include the following: 3-nitro-4-hydroxy-3-sodiumcarboxy-azobenzene, 4-chloro-2- phenylquinazoline, aminoadipic acid, aminoanthracene, aminobiphenyl, 2-amino-5-bromobenzoic acid, 1-amino-5- bromobenzoic acid, 1-amino-4-bromonaphthalene, 2-amino-5- bromopyridine, amino-chlorobenzenesutfonic acid, 2-amino-4- chlorobenzoic acid, 2-amino-5-chlorobenzoic acid, 3-amino-4- chlorobenzoic acid, 4-amino-2-chlorobenzoic acid, 5-amino-2- chlorobenzoic acid, 2-amino-5-chlorobenzonitrile, 2-amino-5- chlorobenzophenone, amino-chlorobenzotrifluoride, 3-amino-6- chloromethyl-2-pyrazinecarbonitrile-4oxide, 2-amino-4-chloro- 6-methylpyridine, 1-amino-4-chloronaphthalene, 2-amino-3- chloro-1,4-naphthoquinone, 2-amino-4-chloro-5-nitrophenol, 2- amino-4-chloro-5-nitrotoluene, 2-amino-4-chloro-4-phenol, 2- amino-5-chloropurine, 2-amino-5-chloropyridine, 3-amino-2- chloropyridine, 5-amino-2-chloropyridine, aminochrysene, 2- amino-p-cresol, 3-amino-p-cresol, 4-amino-p-cresol, 4-amino-m- cresol, 6-amino-m-cresol, 3-aminocrotononitrile, 6-amino-3- cyano-2,4-dimethylpyridine, 5-amino-6-cyano-2-pyrazinyl acetate, 4- [N- (2-methyl-3-cyano-5-pyrazinylmethyl) amino]-

benzoic acid, 3,5-dinitroaniline, 4- (2,4- dinitroanilino) phenol, 2,4-dinitroanisol, 2,4- dinitrobenzaldehyde, 2,6-dinitrobenzaldehyde, 3,5- dinitrobenzamide, 1,2-dinitrobenzene, 1,3-dinitrobenzene, 3,4- dinitrobenzoic acid, 3,5-dinitrobenzoic acid, 3,5- dinitrobenzonitrile, 2,6-dinitro-p-cresol, 4,6-dinitro-o- cresol 2,4-dinitrodiphenylamine, dinitrodurene, 2,4-dinitro- N-ethylaniline, 2,7-dinitrofluorenone, 2,4- dinitrofluorobenzene, 1,3-dinitronaphthalene, 1,5- dinitronaphthalene, 1,8-dinitronaphthalene, 2,4-dinttrophenol, 2,5-dinitrophenol, 2,4-dinitrophenylhydrazine, 3,5- dinitrosalicylic acid, 2,3-dinitrotoluene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, 3,4-dinitrotoluene, 9-nitroanthracene, 4- nitroanthranilic acid, 2-amino-5-trifluoromethyl-1,3,4- thiazole, 7-amino-4- (trifluoromethyl)-coumarine, 9- cyanoanthracene, 3-cyano-4,6-dimethyl-2-hydroxypyridine, 5- cyanoindole, 2-cyano-6-methoxybenzothiazole, 9- cyanophenanthrene, cyanuric chloride, 1,2- diaminoanthraquinone, 3,4-diaminobenzoic acid, 3,5- diaminobenzoic acid, 3,4-diaminobenzophenone, 2,4-diamino-6- (hydroxymethy) pteridine, 2,6-diamino-4-nitrotoluene, 2,3- dicyanohydroquinone, 2,6-dinitroaniline, 2-amino-5-iodobenzoic acid, aminomethoxybenzoic acid 2-amino-4- methoxybenzothiazole, 2-amino-6-methoxybenzothiazole, 5-amino- 2-metoxyphenol, 5-amino-2-methoxypyridine, 2-amino-3- methylbenzoic acid, 2-amino-5-methylbenzoic acid, 2-amino-6- methylbenzoic acid, 3-amino-4-methylbenzoic acid, 4-amino-3- methylbenzoic acid, 2-amino-4-methylbenzophenone, 7-amino-4- methylcoumarin, (100) 3-amino-5-methylisoxazole, (101) 7- amino-4-methy-1,8-naphthylidene-2-ol. Suitable guest compounds include: 4-aminoacetophenone, 4-aminobenzoic acid, 4-amino-alpha, alpha, alpha-trifluorotoluene, 4-amino- benzonitrile, 4-aminocinnamic acid, 4-aminophenol, 4- bromotoluene, 4-bromoaniline, 4-bromoanisole, 4- bromobenzaldehyde, 4-bromobenzonitrile, 4-chlorotoluene, 4- chloroaniline, 4-chloroanisole, 4-chlorobenzaldehyde, 4-

chlorobenzonitrile, 4-chanobenzaldehyde, alpha-cyano-4- hydroxycinnamic acid, 4-cyanophenol, 4-cyanopyridine-N-oxide, 4-fluorotoluene, 4-fluoroaniline, 4-fluoroanisole, 4- fluorobenzaldehyde, 4-fluorobenzonitrile, 4-nitroaniline, 4- nitrobenzamide, 4-nitrobenzojc acid, 4-nitrobenzyl alcohol, 4- nitrocinnamaldehyde, 4-nitrocinnamic acid, 4-nitrophenol, 4- nitrophenetole, 4-nitrophenyl acetate, 4-nitrophenylhydrazine, 4-nitrophenyl isocyanate 4-nitrotoluene 4-nitro-alpha, alpha, alpha-trifluorotoluene.

Examples of the liquid-crystal compound for use in the present invention include the compounds shown in Table 1.

X-A-R-B-Y Formula IV wherein A and B can be aromatic and or aliphatic hydrocarbon six member rings, or substituted six member rings, or nitrogen or oxygen containing six member rings where either oxygen or nitrogen are in the ring along with carbon, and mixtures of any of these; and R is a single bond between the two rings A and B, or (-C=C-) which indicates triple bonded carbons, or CH2CH2 or COO. In formula IV, X and Y each represents an alkyl group, an alkoxy group, an alkoxyalkyl group, an alkylphenyl group, an alkoxyalkylphenyl group, an alkoxyphenyl group, an alkylcyclohexyl group, an alkoxyalkylcyclohexyl group, an alkylcyclohexylphenyl group, a cyanophenyl group, a cyano group, a halogen atom, a fluoromethyl group, a fluoromethoxy group, an alkylphenylalkyl group, an alkoxyphenylalkyl group, an alkylcyclohexylalkyl group, an alkoxyalkoxycyclohexylalkyl group, an alkoxyphenylalkyl group, or an alkylcyclohexylphenylalkyl group, wherein the alkyl chains and alkoxy chains each may have an optically active site therein; and the substituents for the rings can be in addition to hydrogen atoms, a halogen atom, or a cyano group. The phenyl or phenoxy group which may be contained in X and Y may be substituted with at least one substituent selected from a cyano group and halogen atoms, e. g., fluorine and chlorine.

The phenyl groups contained in Formula IV each may be substituted with up to four substituents selected from halogen atoms, e. g., fluorine and chlorine, and a cyano group.) Additionally, fluorinated liquid-crystal compounds having one or more fluorine atoms or fluorinated groups, e. g., --F,--CF sub 3, and--OCF sub 3, can be used in place of conventional cyano-containing liquid-crystal compounds.

The liquid-crystal composition according may also have various additives including ultraviolet absorbers and antioxidants.

Also useful as the guest host composition for space 41 in figure 2 or 3 is a solid solution of an organic guest compound having an electron donative group or an electron attractive group. The organic guest compound can be contained in the nonlinear optical material such as an oriented form through orientation under melting by application of a DC electric field or a magnetic field. An example of such a guest compound is a para-di-substituted benzene derivative where one substituent is an electron donating group and the other substituent located para to the first substituent is an electron withdrawing group.

Other suitable examples from the literature include the use of a polymer liquid crystal as a host and polar molecules as a guest and utilize the orientation under electric field of the polymer liquid crystal to align the polar molecules as noted at (Meredity, G. R., et al.; Macromolecules, 15,1385 (1982)).

Further, as an example of alignment of polar molecules in an amorphous polymer, a polymethyl methacrylate resin with an azo colorant dissolved therein was formed into a film, heated to a temperature above the glass transition point and supplied with a voltage to align the azo colorant molecules, followed further by cooling to fix the resultant structure. (Singer, K. D., Sohn, J. E. and Lalama, S. J.; Appl. Phys, Lett. 49, page 248 (1986)). Also useful can be a mixture of a nonlinear optical-responsive organic compound in

a polymer to obtain a polymer nonlinear optical material (U. S. Pat. No. 4,428,873 ; JP-A (Kokai) 57-45519). A nonlinear optical material comprising an acrylamide resin as a host polymer and a nonlinear optical-responsive organic compound as a guest is useful from (JP-A (Kokai) 62-84139). Also useful is to obtain crystalline growth of a compound having an asymmetric center in a polyoxyalkylene matrix as in (JP-A 62- 246962). Also a polyoxyalkylene matrix can be used composed of the polyoxyalkylene alone or in a mixture with other polymer like poly (methyl methacrylate), poly (vinyl acetate), polystyrene, poly (vinylidene fluoride), poly (vinylidene cyanide-vinyl acetate), poly (vinylidene fluoride- tetrafluoroethylene), poly (vinylidene cyanide-vinyl propionate), poly (vinylidene cyanide-vinyl benzoate), poly (vinyl alcohol), polyimide, etc., polymer liquid crystals, liquid crystals, and powders of inorganic compounds.

When the liquid-crystal composition with the chromogenic agent is the switchable material 43 placed in the space 41 of Figures 2 or 3 the electro-optical article is constituted.

A transparent electrode as coating, layer or films 45 and 47 of Figure 2 or 3 can be produced by forming a transparent electrode layer on the substrate which is either a glass plate or a plate of any of various synthetic resins including acrylic resins, polycarbonate resins, and epoxy resins as mentioned above. The transparent electrode layer can be made of a metal oxide such as, e. g., indium oxide, indium-tin oxide (ITO), or tin oxide. The surface of the transparent electrode layer which is to be in contact with a liquid crystal may be subjected to an alignment treatment if desired.

For the cell device of Figures 2 and 3 there is a difference that occurs as a result of the use of the liquid crystal approach rather than the electrochromic approach.

This is that the electrode layers, which are preferably transparent, located on both substrates or the substrate and

the encapsulating layer have electrode surfaces which have undergone an alignment treatment before the addition of the liquid crystal to space 41.

The alignment treatment can be accomplished, for example, by applying octadecyldimethyl [3- (trimethoxysilyl)- propyl] ammonium chloride, hexadecyltrimethylammonium bromide, or the like for vertical alignment, by applying a polyimide for parallel alignment, by rubbing the surface with a cotton cloth, absorbent cotton, or the like for parallel alignment, or by vapor-depositing an SiOX at a small tilt angle for parallel alignment. These alignment techniques may be suitably used. Another approach for alignment is disclosed and described in copending patent application filed the same day as this application by Patricia Ruzakowski Athey and entitled"Electrodes for Liquid Crystal Cells". Other methods for aligning can be used such as aligning a liquid crystalline compound containing a polymerizable functional group or a polymerizable liquid crystal composition containing such a compound in liquid crystalline state, and then irradiating the material with energy rays such as ultraviolet ray while maintaining in the liquid crystalline state.

As another method for semipermanently fixing the uniform orientation of the mesogenic core of liquid crystal, there has already been known a method which comprises the use of a liquid crystalline polymer compound. In some detail, the method comprises applying a solution of liquid crystalline polymer which exhibits a thermotropic liquid crystallinity to a substrate which is treated to align the liquid crystalline polymer, and then subjecting the material to heat at a temperature at which the liquid crystalline polymer compound exhibits a liquid crystalline phase to obtain a desired orientation of mesogenic core of liquid crystalline polymer.

The polymer compound thus oriented is kept in glass state so that the desired orientation is fixed therein.

EXAMPLES Several liquid crystal cells were constructed in accordance with the following procedure for the materials indicated in Table 1. The cells were fashioned into variable transparency apparatus and tested as indicated in Table 1.

1. Cut Sungate0 500 glass into 2"x 2"pieces. One pair of pieces is used to construct one liquid crystal cell. The Sungate0 500 glass functions as electrodes for the device, and also provides an alignment layer for the liquid crystal-dye mixture.

2. Clean Sungate 500 glass: Spray Sungate 500 glass with 50/50 v/v 2-propanol/deionized water and wipe dry with Technicloth (TEXWIPE) polyester/cellulose wiper.

3. Rubbing the conductive surface of the SungateO 500 glass: Unidirectionally rub the conductive side of one of two pieces of Sungate0 500 glass ten times with a cotton pad (VWR Scientific) wetted with 2-propanol and wrapped around an aluminum bar.

4. Spin coat spacer material onto conductive side of one piece of Sungate 500 glass: Prepare a dilute mixture of 8 micron glass fiber spacer material (EM Industries, Inc.) in 2- propanol (Fisher Optima grade). This mixture must appear cloudy when shaken. Before spin coating, blow off any dust from conductive surface of Sungate0 glass with compressed nitrogen. Mount glass sample onto vacuum chuck of spin coater (Headway Research, Inc.), and then place 5 drops of glass fiber spacer/2-propanol mixture/ (in) 2 of glass area onto the conductive side of glass. Set spin coater to rotate at 1090 rpm for 21 seconds. Remove piece of Sungate0 500 glass from spin coater.

5. Assemble Liquid Crystal cell/Initial sealing: Place the two pieces of Sungate0 500 glass (one with glass fiber

spacers; one without) together so that the conductive sides are facing and the rubbing directions are 180° opposed. Leave -1/4"offset at the pair of opposite edges for electrical connection and filling ; the other pair of opposite edges should be aligned evenly. Hold the cell together with two binder clips. Apply an UV-curable epoxy adhesive (LoctiteX 349) to the two flushly aligned edges for an initial seal.

Cure the UV epoxy by passing the cell through a high intensity UV reactor (RPC Industries). When the epoxy has hardened, remove the binder clips. This creates a cell with a filable volume of-1-3/4"x 2"x 8 microns.

6. Prepare liquid crystal/dichroic dye/photochromic dye mixtures: Mix E7 liquid crystal (EM Industries, Inc.) with G- 472 blue dichroic dye (Nippon, Kankoh, Shikiso, Kenkyusho) and 7-120 blue photochromic dye (PPG Industries Inc.) in glass vials at the following weight percentages: E7 liquid crystal, 95 wt%; G-472 blue dichroic dye, 1 wt%; 7-120 photochromic dye, 4.0 wt%. Heat mixture on a hotplate set at a temperature above the isotropic state of the E7 liquid crystal-i. e. 90°C -and occasionally agitate by shaking until all of the dye particles have dissolved.

7. Filling the Liquid Crystal cell: Place the unfilled cell onto a hot plate (Thermolyne Mirant^) set at 90° C. The cell should be positioned on the hotplate so to allow drop filling along one of the unsealed edges. Draw the warm liquid crystal/dichroic dye/photochromic dye mixture into a pipet, and starting at one corner along the filling edge and ending at the opposite corner, deposit a continuous line of the mixture along the open edge to begin capillary filling. The device is filled when the liquid crystal/dye mixture front has traveled across to the opposite unsealed edge of the cell.

8. Cooling the filled Liquid Crystal cell: Remove cell from hotplate and allow to cool to room temperature. As the

mixture cools, the E7 liquid crystal goes from an isotropic state to the nematic state.

9. Final Sealing of Liquid Crystal Device: Apply 5 minute epoxy (Loctite 100CL) to the two unsealed edges and allow to cure. This completes the fabrication of a guest-host liquid crystal device that incorporates a photochromic dye.

10. Electrical Switching of the Liquid Crystal Device: The liquid crystal device as fabricated above is in the darkened state [exhibits low visible light transmittance (-41% Lta) of a blue color when viewed under fluorescent lighting] when no electric field is supplied to the device. When an electric field is applied to this liquid crystal device, it bleaches [exhibits higher visible light transmittance (-63% Lta) of a light blue color when viewed under fluorescent lighting].

Initially 0-6VDC was used to switch these devices, but 0-6VAC is preferred to switch all liquid crystal devices in order to avoid any cell degradation that might result from use of DC voltage.

11. Photochromic Effect: The photochromic dye in the above described liquid crystal device is not activated by an electrical field, but requires exposure to UV light to bring about a photochromic response. The UV light is absorbed by the photochromic dye molecule which then undergoes a chemical structure change that brings about a visible color change of the dye from almost colorless to dark blue (when viewed under fluorescent lighting). When the above described liquid crystal device in the darkened state is exposed to longwave UV light for less than a minute, the device darkens even further to a lower visible transmittance value (not measured) of a deep blue color (under florescent lighting). When the longwave UV light source is removed, the device bleaches back to the transmittance value of the cell in the dark state in

less than a minute. This photochromic effect has been reproduced a number of times with the same device.

12. Results for several liquid crystal cells are presented in Table I A, B, and C.

Table 1 shows Liquid Crystal Devices Incorporating Photochromic Component where SG500: is Sungate0 500 available from PPG Industries Inc. and IPA is isopropylalcohol or 2- propanol TABLE 1 A Liquid Code Substrate 1 Surface Treatment 1 Crystal Dicroic Dye Ph@ A SG500 Cleaned by spraying with 50:50 v:v E7 - 7<BR> IPA:deionized water, and wiping dry<BR> with TechniCloth#wiper; then<BR> unidirectional-rubbed 10x with black<BR> velvet wetted with IPA<BR> B SG500 Cleaned by spraying with 50:50 v:v E7 - 7<BR> IPA:deionized water, and wiping dry<BR> with TechniCloth#wiper; then<BR> unidirectional-rubbed 10x with black<BR> velvet wetted with IPA<BR> C SC500 Cleaned by spraying with 50:50 v:v E7 Blue G-472 7<BR> IPA:deionized water, and wiping dry (Nippon 95-1),<BR> with TechniCloth#wiper; then 0.8%<BR> unidirectional-rubbed 10x with black<BR> velvet wetted with IPA<BR> D SG500 Cleaned by spraying with 50:50 v:v E7 Blue G-472 7<BR> IPA:deionized water, and wiping dry (Nippon 95-1),<BR> with TechniCloth#wiper; then 0.8%<BR> unidirectional-rubbed 10x with black<BR> velvet wetted with IPA<BR> AA SG500 Cleaned by spraying with 50:50 v:v E7 Purple G-471<BR> IPA:deionized water, and wiping dry (Nippon &num 95-1),<BR> with TechniCloth#wiper; then 1%<BR> unidirectional-rubbed 10x with black<BR> velvet wetted with IPA TABLE 1 A Liquid Code Substrate 1 Surface Treatment 1 Crystal Dicroic Dye Ph@ BB SG500 Cleaned by spraying with 50:50 v:v E7 Purple G-471<BR> IPA:deionized water, and wiping dry (Nippon &num 95-1),<BR> with TechniCloth#wiper; then 1%<BR> unidirectional-rubbed 10x with black<BR> velvet wetted with IPA<BR> CC SG500 Cleaned by spraying with 50:50 v:v E7 Purple G-471 7<BR> IPA:deionized water, and wiping dry (Nippon &num 95-1),<BR> with TechniCloth#wiper; then 1%<BR> unidirectional-rubbed 10x with black<BR> velvet wetted with IPA<BR> AAA SG500 Twice cleaned by spraying with 50:50 E7 7<BR> v:v deionized water, and wiping dry with<BR> TechniCloth#wiper; then unidirectional-<BR> stroked 5x with cotton pad wetted with<BR> IPA and finally unidirectional-stoked 5x<BR> with dry cotton pad<BR> BBB SG500 Twice cleaned by spraying with 50:50 E7 Blue G-472<BR> v:v deionized water, and wiping dry with (Nippon 95-1),<BR> TechniCloth#wiper; then unidirectional- 1.0%<BR> stroked 5x with cotton pad wetted with<BR> IPA and finally unidirectional-stoked 5x<BR> with dry cotton pad<BR> CCC SG500 Twice cleaned by spraying with 50:50 E7 Blue G0472 7<BR> v:v deionized water, and wiping dry with (nippon 95-1),<BR> TechniCloth#wiper; then unidirectional- 1.1%<BR> stroked 5x with cotton pad wetted with<BR> IPA and finally unidirectional-stoked 5x<BR> with dry cotton pad TABLE 1B Surtace Angie 1-2 Code Substrate 2 Treatment 2 (clockwise) Filling Spa A SG500 same as for 1 180 capillary 8<BR> B SG500 same as for 1 180 capillary 8<BR> C SG500 same as for 1 180 capillary 8<BR> D SG500 same as for 1 180 capillary 8<BR> AA SG500 same as for 1 180 capillary 8 TABLE 1B Surtace Angle 1-2 Code Substrate 2 Treatment 2 (clockwise) Filling Spa BB SG500. same as for 1 180 capillary 8<BR> CC SG500. same as for 1 180 capillary 8<BR> AAA SG500. same as for 1 180 capillary 8<BR> BBB SG500. same as for 1 180 capillary<BR> CCC SG500. same as for 1 180 capillary TABLE 1C Code Sub1 Sub 2 Comments A 1 1 weak photochromic effect<BR> B 1 1 weak photochromic effect<BR> C 1 1 too light in darkened state, weak photo-effect<BR> D 1 1 too light in darkened state, weak photo-effect<BR> AA 1 1 noticeable photochromic effect TABLE 1C Code Sub1 Sub 2 Comments BB 1 1 noticeable Photochromic effect<BR> CC 1 1 noticeable Photochromic effect<BR> AAA 2 2 noticeable photochromic effect, no bubbles upon filling<BR> BBB 2 2 bubbles upon filling<BR> CCC 2 2 noticeable photochromic effect, vacuum degassed<BR> liquid crystal-dye mixture for 5min., no bubbles upon<BR> filling